Daniel Dempsey - Academia.edu (original) (raw)
Papers by Daniel Dempsey
Journal of Parenteral and Enteral Nutrition, 1986
To evaluate the temporal pattern of urea excretion in chair-adapted primates (Macaque fasciculari... more To evaluate the temporal pattern of urea excretion in chair-adapted primates (Macaque fascicularis) on continuous total parenteral nutrition (TPN), two groups of five animals were studied. Group I received continuous TPN (75 glucose kcal; 0.56 g nitrogen; and 100 ml fluid per kg per day) while Group II received a single morning isonitrogenous oral meal along with a continuous isovolemic intravenous infusion of 0.45% saline. Urine was collected hourly in group I for 2 days and every 4 hr in group II for 5 days and analyzed for urea content. Time series analysis revealed no periodicity of urea excretion in either group. Six animals were then studied for a total of 46 TPN days to define the relationship between the urea content of a single 3-hr morning urine aliquot and its respective content in a 24-hr collection. A significant linear relationship was found (r = +0.76, p less than 0.01). However, using this relationship, a reasonable estimate (+20%) of measured 24-hr urea output was achieved only 50% of the time using a single 3-hr urea output. Chair-adapted primates maintained on continuous TPN or a single oral meal with continuous saline infusion do not exhibit a periodic pattern of urea excretion. The variability in 3-hr urinary urea output in the chaired primate on continuous TPN does not consistently permit accurate estimation of the coincident 24-hr urinary urea output.
Journal of Surgical Research, 1985
Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The... more Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The objective of this study was to evaluate the level of stress and metabolic alterations associated with surgical placement and subsequent maintenance and use of an indwelling intravenous cannula as measured by resting energy expenditure (REE), respiratory quotient (RQ), urinary nitrogen excretion, and substrate utilization pattern. Nine rats underwent SVC cannulation and six rats underwent sham operation. Postoperatively, animals were starved for 48 hr and then refed either parenterally or orally for 48 hr. Sham-operated animals adapted appropriately to starvation within 24 hr by decreasing REE 14% and increasing utilization of fat (RQ:0.89 -0.78). Hypometabolic adaptation to starvation was delayed in cannulated animals until the second postoperative day, but appropriate alterations in energy substrate utilization were not affected by the presence of cannulae. Cannulae did not affect the metabolic response to oral refeeding with similar increases in REE and similar patterns of substrate utilization in sham-operated and cannulated animals. Animals refed parenterally demonstrated higher REE and apparent fat deposition (RQ > 1) consistent with continuous bypercaloric glucose administration. Urinary nitrogen excretion was not affected by the presence of cannulae. Cannula-associated metabolic alterations are minimal and transient and do not preclude detection and quantification of alterations associated with composition or utilization of exogenous substrates. 0 1985 Academic FTW, IX.
Journal of Parenteral and Enteral Nutrition, 1987
To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requir... more To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.
Journal of Parenteral and Enteral Nutrition, 1986
This paper describes the construction of an indirect calorimeter for measurement of respiratory g... more This paper describes the construction of an indirect calorimeter for measurement of respiratory gas exchange in the chaired primate. Preliminary determinations of energy expenditure and respiratory quotient in five animals under a variety of dietary conditions suggest that this system will prove useful in the laboratory study of primate nutrition, energy metabolism, and cardiorespiratory physiology. Other possible uses and limitations are discussed.
The American Journal of Surgery, 1992
Journal of Surgical Research
Journal of Surgical Oncology, 2015
When performed at select centers, minimally invasive gastrectomy (MIG) for gastric adenocarcinoma... more When performed at select centers, minimally invasive gastrectomy (MIG) for gastric adenocarcinoma is associated with reduced perioperative morbidity, and similar oncologic outcomes as compared to open gastrectomy (OG). Utilization of, and outcomes associated with, MIG in the United States have not been characterized. The National Cancer Database (2010-2011) was queried for AJCC pStage IB-IIIC patients who underwent curative-intent OG (n = 2,303) or MIG (n = 331). Multivariable models identified factors associated with MIG utilization, R0 resection rates, and adequate lymph node staging (LNS). MIG was more frequently utilized for T1/T2 (P < 0.001), N0 (P = 0.022), and stage IB (P = 0.001) tumors. MIG was associated with shorter hospital stay (P < 0.001), equivalent lymph node examination (P = 0.337) and superior rates of R0 resection (P = 0.011) compared with OG. In patients undergoing MIG, R0 resection was associated with performance of near-total/total gastrectomy (OR 3.90, 95%CI 1.10-13.9) and tumors < 5 cm (OR 2.78, 95%CI 1.07-7.26). Adequate LNS was associated with surgery at academic (OR 1.99, 95%CI 1.19-3.32) or high-volume facilities (OR 2.97, 95%CI 1.59-5.54), tumor size ≥ 5 cm (OR 1.85, 95%CI 1.10-3.11), and node positivity (OR 1.75, 95%CI 1.04-2.93). MIG is selectively utilized in cases with favorable tumor characteristics. In such cases, short-term oncologic outcomes are equivalent to those achieved with OG. Worse oncologic outcomes in specific subgroups underscore opportunities for quality improvement. J. Surg. Oncol. 2015;112:616-621. © 2015 Wiley Periodicals, Inc.
Surgical Endoscopy, 2015
Several case series have demonstrated that laparoscopic transhiatal esophagectomy (LTHE) is assoc... more Several case series have demonstrated that laparoscopic transhiatal esophagectomy (LTHE) is associated with favorable perioperative outcomes compared to historical data for open transhiatal esophagectomy (OTHE). Contemporaneous evaluation of open and laparoscopic THE is rare, limiting meaningful comparison of techniques. All patients who underwent OTHE (n = 32) and LTHE (n = 41) during the introduction of the latter procedure at our institution (1/2012-4/2014) were identified, and patient charts were retrospectively reviewed. Indications for operation included 69 patients with esophageal malignancy (adenocarcinoma: 64; squamous cell carcinoma: 4; melanoma: 1) and 4 patients with benign disease. There were no significant differences in clinicopathologic variables between OTHE and LTHE cohorts, except for an increased rate of cardiovascular disease in the LTHE cohort (p = 0.04). There was no significant difference in median operative time or operative complications, yet LTHE was associated with a lower incidence of intraoperative blood transfusion (p < 0.01). There were no 30-day mortalities. LTHE was associated with a reduced time to reach 24-h tube feeding goals (p = 0.02), shorter length of hospital stay (p = 0.01), and 6 % reduced median direct cost (p = 0.04). There were no significant differences in rates of major perioperative morbidities. Patients were followed for a median of 11.0 months during which there were no significant differences between cohorts in disease-free survival or overall survival. When compared to OTHE, LTHE improves surgical outcomes and decreases hospital costs; short-term oncologic outcomes are similar. LTHE is preferable to OTHE in patients requiring transhiatal esophagectomy.
Surgery
The purpose of this study was to determine whether adaptive cytoprotection of gastric mucosa coul... more The purpose of this study was to determine whether adaptive cytoprotection of gastric mucosa could be demonstrated with concentrations of bile acid, which is normally found in the human stomach, and whether cyclooxygenase inhibition, in turn, could blunt the response. Surface epithelial cell exfoliation and ion fluxes were used as end points. A transduodenal gastric cannula was placed, and the pylorus/gastroesophageal junction was ligated in adult male Sprague-Dawley rats that had been anesthetized. In experiment 1 (N = 30), rat stomachs were exposed for 15 minutes to 5 ml of either a neutral test solution (160 mmol/L NaCl, pH 7) or 1 mmol/L acidified taurocholate (ATC) (100 mmol/L HCl, 60 mmol/L NaCl, 1 mmol/L taurocholic acid; pH 1.2). All rats were subsequently exposed for 15 minutes to 5 mmol/L ATC during which time mucosal injury was assessed by measuring net flux of H+, Na+, and K+, volume, and DNA efflux. In experiment 2 (N = 35), all stomachs were pretreated for 15 minutes with 1 mmol/L ATC before mucosal injury with 5 mmol/L ATC (15 minutes). Eighteen rats were pretreated with indomethacin (5 mg/kg) subcutaneously 75 minutes before the experiment was begun, and the same parameters were measured. Pretreatment of rat gastric mucosa with 1 mmol/L ATC significantly attenuated the mucosal injury that was seen with subsequent exposure to 5 mmol/L ATC, resulting in significantly (p less than 0.05) less luminal H+ loss (-16 +/- 4 vs -32 +/- 4 mEq/15 min) and DNA efflux (181 +/- 21 vs 270 +/- 25 micrograms/15 min) than the nonadapted group. Indomethacin pretreatment significantly attenuated the adaptive protective response, resulting in greater loss of H+ (-29 +/- 4 vs -18 +/- 3) and DNA efflux (190 +/- 35 vs 110 +/- 18, both p less than 0.05) after exposure to 5 mmol/L ATC. These studies demonstrate that adaptive cytoprotection of gastric mucosa occurs with physiologic concentrations of an irritant that is normally present in the stomach. Indomethacin blunts this effect, which suggests that adaptive cytoprotection in this setting may be mediated by production of endogenous prostaglandins.
The American surgeon
Leukotrienes C4 and D4 are potent vasoconstrictors and have been proposed as mediators of the sev... more Leukotrienes C4 and D4 are potent vasoconstrictors and have been proposed as mediators of the severe gastric mucosal injury caused by a variety of necrotizing agents. The purpose of this study was to investigate the role of leukotrienes on the less severe gastric mucosal injury caused by low concentrations of bile acid. Prior to injury with 5 mM acidified taurocholate (pH 1.2), rat stomachs were pretreated with either normal saline, leukotrienes C4 or D4 (10(-6), 10(-8), and 10(-9) M), or SKF-104353 (a leukotriene D4 receptor antagonist 10(-7) M). Injury was assessed by measuring net transmucosal hydrogen ion flux, luminal appearance of DNA, and histologic injury. Topical pretreatment with LTC4 and LTD4 significantly increased bile acid-induced luminal hydrogen ion loss and DNA accumulation in a dose-dependent manner. Leukotriene receptor blockade with SKF-104353 significantly decreased these parameters. Thus, both LTC4 and LTD4 exacerbate the gastric mucosal injury caused by the application of low concentrations of bile acid while leukotriene receptor blockade reduces this injury (corroborated by histologic injury analysis). This study suggests that leukotrienes may be mediators of bile acid-induced gastric mucosal injury.
The American Journal of Gastroenterology
The American surgeon
Topical isoproterenol protects the gastric mucosa from the severe necrosis induced by 100 per cen... more Topical isoproterenol protects the gastric mucosa from the severe necrosis induced by 100 per cent ethanol. Its effect on gastric mucosal blood flow is unknown. The purpose of this study was to determine the effect of topical isoproterenol on gastric mucosal blood flow and on the less severe gastric mucosal injury caused by dilute bile acid. Prior to injury with topical 5 mM acidified taurocholate (pH 1.2), stomachs were pretreated with either saline or isoproterenol (low dose = 50 micrograms/kg; high dose = 500 micrograms/kg). Mucosal injury was assessed by measuring net transmucosal ion fluxes (H, K) and the appearance of DNA into the gastric lumen (DNAE). Gastric mucosal blood flow was determined by using laser doppler. Pretreatment with isoproterenol significantly decreased bile acid-induced net transmucosal ion fluxes and luminal accumulation of DNA, suggesting mucosal protection. Furthermore, this effect was dose-dependent on H and DNAE but not K. Pretreatment with topical hig...
Surgery
Sensory neurons have been proposed to play a critical role in the protection of the gastric mucos... more Sensory neurons have been proposed to play a critical role in the protection of the gastric mucosa from a variety of necrotizing agents. The purposes of this study were (1) to investigate the effect of topical capsaicin, a sensory neuron stimulant, on the gastric mucosal injury caused by the topical application of low concentrations of bile acid and (2) to determine whether local neuronal blockade with topical lidocaine or cyclooxygenase blockade with systemic indomethacin has any effect during pretreatment with capsaicin. Before injury with topical 5 mmol/L acidified taurocholate (pH 1.2) rat stomachs were pretreated with either vehicle or capsaicin (160 mmol/L), both with and without prior administration of either lidocaine (1%) or indomethacin (5 mg/kg subcutaneously). Injury was assessed by measuring net transmucosal ion fluxes, the appearance of deoxyribonucleic acid into the gastric lumen, and gross and histologic injury scores. Pretreatment with topical capsaicin significantl...
The American journal of physiology
Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined ... more Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined how time after injury and lesion severity contribute to the decreased contractility and how colitis alters the calcium-handling properties of the affected muscle. Distal colitis was induced in rats by intrarectal administration of 4% acetic acid. Contractile responses to acetylcholine, increased extracellular potassium, and the G protein activator NaF were determined for circular muscle strips from sham control and colitic rats at days 1, 2, 3, 7, and 14 postenemas. Acetylcholine stimulation of tissues from day 3 colitic rats was performed in a zero calcium buffer, in the presence of nifedipine, and after depletion of intracellular stores of calcium. The colitis was graded macroscopically as mild, moderate, or severe. Regardless of agonist, maximal decrease in force developed 2 to 3 days posttreatment, followed by a gradual return to control by day 14. The inhibitory effect of colitis on...
Annals of surgery, 2015
To compare the efficacy of adjuvant chemoradiotherapy (CRT) and chemotherapy alone (CA) in gastri... more To compare the efficacy of adjuvant chemoradiotherapy (CRT) and chemotherapy alone (CA) in gastric adenocarcinoma patients undergoing gastrectomy in the United States (US). A majority of US gastric adenocarcinoma patients are inadequately staged (<15 nodes examined). Despite this, and limited data comparing adjuvant CRT with CA in US patients, national guidelines endorse CA in selected patients undergoing D2 lymphadenectomy. Resected stage IB-III gastric adenocarcinoma patients receiving adjuvant CRT or CA (n = 3008) were identified in the National Cancer Database (1998-2006). Cox regression identified covariates associated with overall survival (OS). CRT and CA cohorts were matched (3:1) by propensity scores based on the likelihood of receiving CA. OS was compared by Kaplan-Meier estimates. Adjuvant CA was associated with an increased risk of death (HR 1.29, P < 0.001) relative to CRT. Inadequate lymph node staging (LNS) and nodal positivity were strong predictors of risk-adj...
Surgery for Obesity and Related Diseases, 2015
Robotic technology is increasingly prevalent in bariatric surgery, yet there are national deficie... more Robotic technology is increasingly prevalent in bariatric surgery, yet there are national deficiencies in exposure of surgical residents to robotic techniques. The purpose of this study is to accurately characterize the perioperative outcomes of a resident teaching model using the robotic-assisted sleeve gastrectomy. University Hospital. We identified 411 consecutive patients who underwent robotic sleeve gastrectomy at our institution from a prospectively maintained administrative database. Perioperative morbidity, operative time, and supply cost of the procedure were analyzed. Mean operative time was 96.4±24.9 minutes; mean robot usage time was 63.9 minutes (range 30.0-122.0 min). Ninety-day morbidities included reoperation (0.72%), major bleeding complications (0.48%), staple line leak (0.24%), stricture (0.97%), need for blood transfusion (3.86%), surgical site infection (1.69%), deep vein thrombosis (0.48%), and pulmonary embolism (0.48%). Mortality was nil. The resident cohort achieved operative time plateaus after five consecutive cases. Subset analysis for fiscal year 2014 demonstrated significantly increased supply cost for robotic sleeve gastrectomy compared with its laparoscopic equivalent. Robotic-assisted sleeve gastrectomy can be instituted as a model for resident robotic education with rates of morbidity and operative times equivalent to historical laparoscopic controls. The robot&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s enhanced ergonomics and its opportunity for resident education must be weighed against its increased supply cost.
The American Journal of Surgery, 1992
Pretreatment with the mild irritant 1 mmol acidified taurocholate protects the gastric mucosa fro... more Pretreatment with the mild irritant 1 mmol acidified taurocholate protects the gastric mucosa from the injury induced by the subsequent application of 5 mmol acidified taurocholate, a phenomenon referred to as "adaptive cytoprotection." How this occurs remains an enigma. The purpose of this study was to investigate the role of sensory neurons and mucus secretion in this phenomenon. Prior to injury with 5 mmol acidified taurocholate (pH 1.2), the stomachs of six groups of rats were subjected to the following protocol. Two groups were topically pretreated with either saline or the mild irritant 1 mmol acidified taurocholate. Two other groups received the topical anesthetic 1% lidocaine prior to pretreatment with either saline or 1 mmol acidified taurocholate. The last two groups got the mucolytic agent 10% N-acetylcysteine (NAC) after pretreatment with either saline or 1 mmol acidified taurocholate. Injury was assessed by measuring net transmucosal ion fluxes, luminal appearance of deoxyribonucleic acid (DNA), and gross and histologic injury. Pretreatment with the mild irritant 1 mmol acidified taurocholate significantly decreased bile acid-induced luminal ion fluxes and DNA accumulation, suggesting mucosal protection (corroborated by gross and histologic injury analysis). This effect was negated by lidocaine but not by NAC. Thus, it appears that sensory neurons, and not increased mucus secretion, play a critical role in adaptive cytoprotection.
The American Journal of Surgery, 1993
ABSTRACT Topical isoproterenol is a potent protective agent against bile acid-induced gastric muc... more ABSTRACT Topical isoproterenol is a potent protective agent against bile acid-induced gastric mucosal injury in hypotensive and normotensive rats. This study was undertaken to ascertain what role endogenous prostaglandins and gastric mucosal blood flow play in isoproterenol-induced protection. Accordingly, anesthetized, fasted rats were given the cyclooxygenase inhibitor, indomethacin (5 mg/kg subcutaneously), 30 min prior to topical pretreatment with 3 ml of intragastric saline, isoproterenol (3 microM), or 16,16-dimethyl prostaglandin E2 (3 microM) for 15 min. Gastric injury was induced with topical 5 mM acidified taurocholate and damage assessed by measuring net transmucosal ion fluxes, the appearance of DNA into the gastric lumen, and histology of the gastric epithelium. In a separate set of experiments, the effects of topical isoproterenol on gastric mucosal blood flow (laser Doppler flowmetry) and luminal PGE2 concentrations (125I radioimmunoassay) were examined. Pretreatment with topical isoproterenol or 16,16-dimethyl prostaglandin E2 significantly decreased bile acid-induced net luminal ion fluxes and DNA accumulation, suggesting mucosal protection. The protective effect of isoproterenol, but not 16,16-dimethyl prostaglandin E2, was negated by indomethacin (corroborated by histology). Further, isoproterenol did not significantly alter gastric mucosal blood flow, but did augment luminal PGE2 concentrations, an effect also abolished by indomethacin. Thus, isoproterenol appears to protect the gastric mucosa from the damaging effects of bile acid through a mechanism that requires the synthesis and release of cytoprotective endogenous prostaglandins.
Surgical Endoscopy, 1999
Minimally invasive esophagomyotomy is replacing open surgery for achalasia, but data comparing th... more Minimally invasive esophagomyotomy is replacing open surgery for achalasia, but data comparing these procedures performed by the same surgical team are sparse. The purpose of this study was to compare the morbidity and clinical outcome following laparoscopic and open esophagomyotomy. Twelve consecutive patients referred for elective surgery between August 1995 and August 1997 underwent laparoscopic myotomy and partial fundoplication. They were compared to a group of 10 patients chosen from a larger pool of 20 patients who had open surgery during the same period performed by our own group. The mean length of follow-up in the laparoscopic group was 16 months; in the open group, it was 60 months. Both groups had similar demographics and clinical features. Each patient had at least one previous pneumatic dilatation. Inpatient records were reviewed. Patients were interviewed using a symptom assessment and patient satisfaction questionnaire. As compared to the open operation, laparoscopic esophagomyotomy with partial fundoplication resulted in significantly (p &amp;lt; 0.05) less blood loss (50 +/- 26 cc versus 220 +/- 127 cc), parenteral narcotic use (2.1 +/- 1.0 days versus 5.3 +/- 1.4 days), time in hospital (2.7 +/- 1.0 days versus 8.8 +/- 2.6 days), and time off work (19 +/- 16 days versus 85 +/- 60 days). There were similar results for the laparoscopic and open groups in the improvement in dysphagia (92% versus 90%) and patient satisfaction with surgery (84% versus 80%). Laparoscopic esophagomyotomy for achalasia results in symptomatic improvement and high patient satisfaction comparable to the open procedure but with significantly less morbidity.
Journal of Surgical Research, 1994
In shocked animals, topical application of bile acids at low pH to gastric mucosa results in gros... more In shocked animals, topical application of bile acids at low pH to gastric mucosa results in gross mucosal injury. Both systemic prostaglandins and isoproterenol reduce this injury, but side effects may limit their clinical usefulness. The purpose of this study was to determine the effect of topical pretreatment with isoproterenol and prostaglandin E2 on gastric mucosal injury induced by low concentrations of bile acid in shocked and normotensive rats. Mucosal injury was assessed by measuring net transmucosal ion fluxes (H+,K+) and luminal accumulation of DNA (DNAE), a sensitive and specific indicator of gastric mucosal cell exfoliation. In this model of mucosal injury, pretreatment with prostaglandin E2 or isoproterenol significantly and dose dependently decreased luminal hydrogen loss, potassium gain, and DNA accumulation in both shocked and normotensive animals. Thus, both topical prostaglandin E2 and isoproterenol reduce gastric mucosal injury caused by low concentrations of bile acid in shocked and normotensive rats, findings corroborated by histology. These findings provide a physiologic basis for the possible use of these agents as prophylaxis or treatment of stress gastritis and gastroduodenal ulcer in the critically ill patient.
Journal of Parenteral and Enteral Nutrition, 1986
To evaluate the temporal pattern of urea excretion in chair-adapted primates (Macaque fasciculari... more To evaluate the temporal pattern of urea excretion in chair-adapted primates (Macaque fascicularis) on continuous total parenteral nutrition (TPN), two groups of five animals were studied. Group I received continuous TPN (75 glucose kcal; 0.56 g nitrogen; and 100 ml fluid per kg per day) while Group II received a single morning isonitrogenous oral meal along with a continuous isovolemic intravenous infusion of 0.45% saline. Urine was collected hourly in group I for 2 days and every 4 hr in group II for 5 days and analyzed for urea content. Time series analysis revealed no periodicity of urea excretion in either group. Six animals were then studied for a total of 46 TPN days to define the relationship between the urea content of a single 3-hr morning urine aliquot and its respective content in a 24-hr collection. A significant linear relationship was found (r = +0.76, p less than 0.01). However, using this relationship, a reasonable estimate (+20%) of measured 24-hr urea output was achieved only 50% of the time using a single 3-hr urea output. Chair-adapted primates maintained on continuous TPN or a single oral meal with continuous saline infusion do not exhibit a periodic pattern of urea excretion. The variability in 3-hr urinary urea output in the chaired primate on continuous TPN does not consistently permit accurate estimation of the coincident 24-hr urinary urea output.
Journal of Surgical Research, 1985
Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The... more Nonrestraining" superior vena cava (SVC) cannulae are commonly used in rat metabolic studies. The objective of this study was to evaluate the level of stress and metabolic alterations associated with surgical placement and subsequent maintenance and use of an indwelling intravenous cannula as measured by resting energy expenditure (REE), respiratory quotient (RQ), urinary nitrogen excretion, and substrate utilization pattern. Nine rats underwent SVC cannulation and six rats underwent sham operation. Postoperatively, animals were starved for 48 hr and then refed either parenterally or orally for 48 hr. Sham-operated animals adapted appropriately to starvation within 24 hr by decreasing REE 14% and increasing utilization of fat (RQ:0.89 -0.78). Hypometabolic adaptation to starvation was delayed in cannulated animals until the second postoperative day, but appropriate alterations in energy substrate utilization were not affected by the presence of cannulae. Cannulae did not affect the metabolic response to oral refeeding with similar increases in REE and similar patterns of substrate utilization in sham-operated and cannulated animals. Animals refed parenterally demonstrated higher REE and apparent fat deposition (RQ > 1) consistent with continuous bypercaloric glucose administration. Urinary nitrogen excretion was not affected by the presence of cannulae. Cannula-associated metabolic alterations are minimal and transient and do not preclude detection and quantification of alterations associated with composition or utilization of exogenous substrates. 0 1985 Academic FTW, IX.
Journal of Parenteral and Enteral Nutrition, 1987
To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requir... more To determine the prevalence of abnormal vitamin levels in an adult hospitalized population requiring total parenteral nutrition (TPN) and to assess the effect of routine parenteral vitamin therapy on vitamin levels, we studied 35 general surgical patients. Assays for 12 vitamins were performed both before and after a standard 10-day course of TPN. Patients were given nothing by mouth. The first 25 patients received a daily parenteral vitamin mixture tailored to the recommendations of the Nutrition Advisory Group of The American Medical Association (maintenance dose). The final 10 patients were given a parenteral multivitamin dose providing substantially greater amounts of most vitamins (repletion dose). Only 58% (190/324) of pre-TPN vitamin levels were normal, 25% were low, and 17% were high. No patient had fewer than two abnormal baseline levels. Vitamin levels did not correlate with serum albumin, body weight, or nitrogen balance. After 10 days of treatment, only 39% of low pre-TPN vitamin levels improved; most (45/62) of the low posttreatment levels were low at baseline. The higher repletion dose resulted in a significantly (p less than 0.01) greater percent increase in vitamin A, C, and pyridoxine levels. The prevalence of abnormal vitamin levels in this population is high (42%). Standard parenteral vitamin therapy leads to marginal improvement in abnormally low pre-TPN vitamin levels.
Journal of Parenteral and Enteral Nutrition, 1986
This paper describes the construction of an indirect calorimeter for measurement of respiratory g... more This paper describes the construction of an indirect calorimeter for measurement of respiratory gas exchange in the chaired primate. Preliminary determinations of energy expenditure and respiratory quotient in five animals under a variety of dietary conditions suggest that this system will prove useful in the laboratory study of primate nutrition, energy metabolism, and cardiorespiratory physiology. Other possible uses and limitations are discussed.
The American Journal of Surgery, 1992
Journal of Surgical Research
Journal of Surgical Oncology, 2015
When performed at select centers, minimally invasive gastrectomy (MIG) for gastric adenocarcinoma... more When performed at select centers, minimally invasive gastrectomy (MIG) for gastric adenocarcinoma is associated with reduced perioperative morbidity, and similar oncologic outcomes as compared to open gastrectomy (OG). Utilization of, and outcomes associated with, MIG in the United States have not been characterized. The National Cancer Database (2010-2011) was queried for AJCC pStage IB-IIIC patients who underwent curative-intent OG (n = 2,303) or MIG (n = 331). Multivariable models identified factors associated with MIG utilization, R0 resection rates, and adequate lymph node staging (LNS). MIG was more frequently utilized for T1/T2 (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), N0 (P = 0.022), and stage IB (P = 0.001) tumors. MIG was associated with shorter hospital stay (P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.001), equivalent lymph node examination (P = 0.337) and superior rates of R0 resection (P = 0.011) compared with OG. In patients undergoing MIG, R0 resection was associated with performance of near-total/total gastrectomy (OR 3.90, 95%CI 1.10-13.9) and tumors &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 5 cm (OR 2.78, 95%CI 1.07-7.26). Adequate LNS was associated with surgery at academic (OR 1.99, 95%CI 1.19-3.32) or high-volume facilities (OR 2.97, 95%CI 1.59-5.54), tumor size ≥ 5 cm (OR 1.85, 95%CI 1.10-3.11), and node positivity (OR 1.75, 95%CI 1.04-2.93). MIG is selectively utilized in cases with favorable tumor characteristics. In such cases, short-term oncologic outcomes are equivalent to those achieved with OG. Worse oncologic outcomes in specific subgroups underscore opportunities for quality improvement. J. Surg. Oncol. 2015;112:616-621. © 2015 Wiley Periodicals, Inc.
Surgical Endoscopy, 2015
Several case series have demonstrated that laparoscopic transhiatal esophagectomy (LTHE) is assoc... more Several case series have demonstrated that laparoscopic transhiatal esophagectomy (LTHE) is associated with favorable perioperative outcomes compared to historical data for open transhiatal esophagectomy (OTHE). Contemporaneous evaluation of open and laparoscopic THE is rare, limiting meaningful comparison of techniques. All patients who underwent OTHE (n = 32) and LTHE (n = 41) during the introduction of the latter procedure at our institution (1/2012-4/2014) were identified, and patient charts were retrospectively reviewed. Indications for operation included 69 patients with esophageal malignancy (adenocarcinoma: 64; squamous cell carcinoma: 4; melanoma: 1) and 4 patients with benign disease. There were no significant differences in clinicopathologic variables between OTHE and LTHE cohorts, except for an increased rate of cardiovascular disease in the LTHE cohort (p = 0.04). There was no significant difference in median operative time or operative complications, yet LTHE was associated with a lower incidence of intraoperative blood transfusion (p &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.01). There were no 30-day mortalities. LTHE was associated with a reduced time to reach 24-h tube feeding goals (p = 0.02), shorter length of hospital stay (p = 0.01), and 6 % reduced median direct cost (p = 0.04). There were no significant differences in rates of major perioperative morbidities. Patients were followed for a median of 11.0 months during which there were no significant differences between cohorts in disease-free survival or overall survival. When compared to OTHE, LTHE improves surgical outcomes and decreases hospital costs; short-term oncologic outcomes are similar. LTHE is preferable to OTHE in patients requiring transhiatal esophagectomy.
Surgery
The purpose of this study was to determine whether adaptive cytoprotection of gastric mucosa coul... more The purpose of this study was to determine whether adaptive cytoprotection of gastric mucosa could be demonstrated with concentrations of bile acid, which is normally found in the human stomach, and whether cyclooxygenase inhibition, in turn, could blunt the response. Surface epithelial cell exfoliation and ion fluxes were used as end points. A transduodenal gastric cannula was placed, and the pylorus/gastroesophageal junction was ligated in adult male Sprague-Dawley rats that had been anesthetized. In experiment 1 (N = 30), rat stomachs were exposed for 15 minutes to 5 ml of either a neutral test solution (160 mmol/L NaCl, pH 7) or 1 mmol/L acidified taurocholate (ATC) (100 mmol/L HCl, 60 mmol/L NaCl, 1 mmol/L taurocholic acid; pH 1.2). All rats were subsequently exposed for 15 minutes to 5 mmol/L ATC during which time mucosal injury was assessed by measuring net flux of H+, Na+, and K+, volume, and DNA efflux. In experiment 2 (N = 35), all stomachs were pretreated for 15 minutes with 1 mmol/L ATC before mucosal injury with 5 mmol/L ATC (15 minutes). Eighteen rats were pretreated with indomethacin (5 mg/kg) subcutaneously 75 minutes before the experiment was begun, and the same parameters were measured. Pretreatment of rat gastric mucosa with 1 mmol/L ATC significantly attenuated the mucosal injury that was seen with subsequent exposure to 5 mmol/L ATC, resulting in significantly (p less than 0.05) less luminal H+ loss (-16 +/- 4 vs -32 +/- 4 mEq/15 min) and DNA efflux (181 +/- 21 vs 270 +/- 25 micrograms/15 min) than the nonadapted group. Indomethacin pretreatment significantly attenuated the adaptive protective response, resulting in greater loss of H+ (-29 +/- 4 vs -18 +/- 3) and DNA efflux (190 +/- 35 vs 110 +/- 18, both p less than 0.05) after exposure to 5 mmol/L ATC. These studies demonstrate that adaptive cytoprotection of gastric mucosa occurs with physiologic concentrations of an irritant that is normally present in the stomach. Indomethacin blunts this effect, which suggests that adaptive cytoprotection in this setting may be mediated by production of endogenous prostaglandins.
The American surgeon
Leukotrienes C4 and D4 are potent vasoconstrictors and have been proposed as mediators of the sev... more Leukotrienes C4 and D4 are potent vasoconstrictors and have been proposed as mediators of the severe gastric mucosal injury caused by a variety of necrotizing agents. The purpose of this study was to investigate the role of leukotrienes on the less severe gastric mucosal injury caused by low concentrations of bile acid. Prior to injury with 5 mM acidified taurocholate (pH 1.2), rat stomachs were pretreated with either normal saline, leukotrienes C4 or D4 (10(-6), 10(-8), and 10(-9) M), or SKF-104353 (a leukotriene D4 receptor antagonist 10(-7) M). Injury was assessed by measuring net transmucosal hydrogen ion flux, luminal appearance of DNA, and histologic injury. Topical pretreatment with LTC4 and LTD4 significantly increased bile acid-induced luminal hydrogen ion loss and DNA accumulation in a dose-dependent manner. Leukotriene receptor blockade with SKF-104353 significantly decreased these parameters. Thus, both LTC4 and LTD4 exacerbate the gastric mucosal injury caused by the application of low concentrations of bile acid while leukotriene receptor blockade reduces this injury (corroborated by histologic injury analysis). This study suggests that leukotrienes may be mediators of bile acid-induced gastric mucosal injury.
The American Journal of Gastroenterology
The American surgeon
Topical isoproterenol protects the gastric mucosa from the severe necrosis induced by 100 per cen... more Topical isoproterenol protects the gastric mucosa from the severe necrosis induced by 100 per cent ethanol. Its effect on gastric mucosal blood flow is unknown. The purpose of this study was to determine the effect of topical isoproterenol on gastric mucosal blood flow and on the less severe gastric mucosal injury caused by dilute bile acid. Prior to injury with topical 5 mM acidified taurocholate (pH 1.2), stomachs were pretreated with either saline or isoproterenol (low dose = 50 micrograms/kg; high dose = 500 micrograms/kg). Mucosal injury was assessed by measuring net transmucosal ion fluxes (H, K) and the appearance of DNA into the gastric lumen (DNAE). Gastric mucosal blood flow was determined by using laser doppler. Pretreatment with isoproterenol significantly decreased bile acid-induced net transmucosal ion fluxes and luminal accumulation of DNA, suggesting mucosal protection. Furthermore, this effect was dose-dependent on H and DNAE but not K. Pretreatment with topical hig...
Surgery
Sensory neurons have been proposed to play a critical role in the protection of the gastric mucos... more Sensory neurons have been proposed to play a critical role in the protection of the gastric mucosa from a variety of necrotizing agents. The purposes of this study were (1) to investigate the effect of topical capsaicin, a sensory neuron stimulant, on the gastric mucosal injury caused by the topical application of low concentrations of bile acid and (2) to determine whether local neuronal blockade with topical lidocaine or cyclooxygenase blockade with systemic indomethacin has any effect during pretreatment with capsaicin. Before injury with topical 5 mmol/L acidified taurocholate (pH 1.2) rat stomachs were pretreated with either vehicle or capsaicin (160 mmol/L), both with and without prior administration of either lidocaine (1%) or indomethacin (5 mg/kg subcutaneously). Injury was assessed by measuring net transmucosal ion fluxes, the appearance of deoxyribonucleic acid into the gastric lumen, and gross and histologic injury scores. Pretreatment with topical capsaicin significantl...
The American journal of physiology
Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined ... more Distal colitis decreases the contractility of the underlying circular smooth muscle. We examined how time after injury and lesion severity contribute to the decreased contractility and how colitis alters the calcium-handling properties of the affected muscle. Distal colitis was induced in rats by intrarectal administration of 4% acetic acid. Contractile responses to acetylcholine, increased extracellular potassium, and the G protein activator NaF were determined for circular muscle strips from sham control and colitic rats at days 1, 2, 3, 7, and 14 postenemas. Acetylcholine stimulation of tissues from day 3 colitic rats was performed in a zero calcium buffer, in the presence of nifedipine, and after depletion of intracellular stores of calcium. The colitis was graded macroscopically as mild, moderate, or severe. Regardless of agonist, maximal decrease in force developed 2 to 3 days posttreatment, followed by a gradual return to control by day 14. The inhibitory effect of colitis on...
Annals of surgery, 2015
To compare the efficacy of adjuvant chemoradiotherapy (CRT) and chemotherapy alone (CA) in gastri... more To compare the efficacy of adjuvant chemoradiotherapy (CRT) and chemotherapy alone (CA) in gastric adenocarcinoma patients undergoing gastrectomy in the United States (US). A majority of US gastric adenocarcinoma patients are inadequately staged (<15 nodes examined). Despite this, and limited data comparing adjuvant CRT with CA in US patients, national guidelines endorse CA in selected patients undergoing D2 lymphadenectomy. Resected stage IB-III gastric adenocarcinoma patients receiving adjuvant CRT or CA (n = 3008) were identified in the National Cancer Database (1998-2006). Cox regression identified covariates associated with overall survival (OS). CRT and CA cohorts were matched (3:1) by propensity scores based on the likelihood of receiving CA. OS was compared by Kaplan-Meier estimates. Adjuvant CA was associated with an increased risk of death (HR 1.29, P < 0.001) relative to CRT. Inadequate lymph node staging (LNS) and nodal positivity were strong predictors of risk-adj...
Surgery for Obesity and Related Diseases, 2015
Robotic technology is increasingly prevalent in bariatric surgery, yet there are national deficie... more Robotic technology is increasingly prevalent in bariatric surgery, yet there are national deficiencies in exposure of surgical residents to robotic techniques. The purpose of this study is to accurately characterize the perioperative outcomes of a resident teaching model using the robotic-assisted sleeve gastrectomy. University Hospital. We identified 411 consecutive patients who underwent robotic sleeve gastrectomy at our institution from a prospectively maintained administrative database. Perioperative morbidity, operative time, and supply cost of the procedure were analyzed. Mean operative time was 96.4±24.9 minutes; mean robot usage time was 63.9 minutes (range 30.0-122.0 min). Ninety-day morbidities included reoperation (0.72%), major bleeding complications (0.48%), staple line leak (0.24%), stricture (0.97%), need for blood transfusion (3.86%), surgical site infection (1.69%), deep vein thrombosis (0.48%), and pulmonary embolism (0.48%). Mortality was nil. The resident cohort achieved operative time plateaus after five consecutive cases. Subset analysis for fiscal year 2014 demonstrated significantly increased supply cost for robotic sleeve gastrectomy compared with its laparoscopic equivalent. Robotic-assisted sleeve gastrectomy can be instituted as a model for resident robotic education with rates of morbidity and operative times equivalent to historical laparoscopic controls. The robot&amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s enhanced ergonomics and its opportunity for resident education must be weighed against its increased supply cost.
The American Journal of Surgery, 1992
Pretreatment with the mild irritant 1 mmol acidified taurocholate protects the gastric mucosa fro... more Pretreatment with the mild irritant 1 mmol acidified taurocholate protects the gastric mucosa from the injury induced by the subsequent application of 5 mmol acidified taurocholate, a phenomenon referred to as "adaptive cytoprotection." How this occurs remains an enigma. The purpose of this study was to investigate the role of sensory neurons and mucus secretion in this phenomenon. Prior to injury with 5 mmol acidified taurocholate (pH 1.2), the stomachs of six groups of rats were subjected to the following protocol. Two groups were topically pretreated with either saline or the mild irritant 1 mmol acidified taurocholate. Two other groups received the topical anesthetic 1% lidocaine prior to pretreatment with either saline or 1 mmol acidified taurocholate. The last two groups got the mucolytic agent 10% N-acetylcysteine (NAC) after pretreatment with either saline or 1 mmol acidified taurocholate. Injury was assessed by measuring net transmucosal ion fluxes, luminal appearance of deoxyribonucleic acid (DNA), and gross and histologic injury. Pretreatment with the mild irritant 1 mmol acidified taurocholate significantly decreased bile acid-induced luminal ion fluxes and DNA accumulation, suggesting mucosal protection (corroborated by gross and histologic injury analysis). This effect was negated by lidocaine but not by NAC. Thus, it appears that sensory neurons, and not increased mucus secretion, play a critical role in adaptive cytoprotection.
The American Journal of Surgery, 1993
ABSTRACT Topical isoproterenol is a potent protective agent against bile acid-induced gastric muc... more ABSTRACT Topical isoproterenol is a potent protective agent against bile acid-induced gastric mucosal injury in hypotensive and normotensive rats. This study was undertaken to ascertain what role endogenous prostaglandins and gastric mucosal blood flow play in isoproterenol-induced protection. Accordingly, anesthetized, fasted rats were given the cyclooxygenase inhibitor, indomethacin (5 mg/kg subcutaneously), 30 min prior to topical pretreatment with 3 ml of intragastric saline, isoproterenol (3 microM), or 16,16-dimethyl prostaglandin E2 (3 microM) for 15 min. Gastric injury was induced with topical 5 mM acidified taurocholate and damage assessed by measuring net transmucosal ion fluxes, the appearance of DNA into the gastric lumen, and histology of the gastric epithelium. In a separate set of experiments, the effects of topical isoproterenol on gastric mucosal blood flow (laser Doppler flowmetry) and luminal PGE2 concentrations (125I radioimmunoassay) were examined. Pretreatment with topical isoproterenol or 16,16-dimethyl prostaglandin E2 significantly decreased bile acid-induced net luminal ion fluxes and DNA accumulation, suggesting mucosal protection. The protective effect of isoproterenol, but not 16,16-dimethyl prostaglandin E2, was negated by indomethacin (corroborated by histology). Further, isoproterenol did not significantly alter gastric mucosal blood flow, but did augment luminal PGE2 concentrations, an effect also abolished by indomethacin. Thus, isoproterenol appears to protect the gastric mucosa from the damaging effects of bile acid through a mechanism that requires the synthesis and release of cytoprotective endogenous prostaglandins.
Surgical Endoscopy, 1999
Minimally invasive esophagomyotomy is replacing open surgery for achalasia, but data comparing th... more Minimally invasive esophagomyotomy is replacing open surgery for achalasia, but data comparing these procedures performed by the same surgical team are sparse. The purpose of this study was to compare the morbidity and clinical outcome following laparoscopic and open esophagomyotomy. Twelve consecutive patients referred for elective surgery between August 1995 and August 1997 underwent laparoscopic myotomy and partial fundoplication. They were compared to a group of 10 patients chosen from a larger pool of 20 patients who had open surgery during the same period performed by our own group. The mean length of follow-up in the laparoscopic group was 16 months; in the open group, it was 60 months. Both groups had similar demographics and clinical features. Each patient had at least one previous pneumatic dilatation. Inpatient records were reviewed. Patients were interviewed using a symptom assessment and patient satisfaction questionnaire. As compared to the open operation, laparoscopic esophagomyotomy with partial fundoplication resulted in significantly (p &amp;lt; 0.05) less blood loss (50 +/- 26 cc versus 220 +/- 127 cc), parenteral narcotic use (2.1 +/- 1.0 days versus 5.3 +/- 1.4 days), time in hospital (2.7 +/- 1.0 days versus 8.8 +/- 2.6 days), and time off work (19 +/- 16 days versus 85 +/- 60 days). There were similar results for the laparoscopic and open groups in the improvement in dysphagia (92% versus 90%) and patient satisfaction with surgery (84% versus 80%). Laparoscopic esophagomyotomy for achalasia results in symptomatic improvement and high patient satisfaction comparable to the open procedure but with significantly less morbidity.
Journal of Surgical Research, 1994
In shocked animals, topical application of bile acids at low pH to gastric mucosa results in gros... more In shocked animals, topical application of bile acids at low pH to gastric mucosa results in gross mucosal injury. Both systemic prostaglandins and isoproterenol reduce this injury, but side effects may limit their clinical usefulness. The purpose of this study was to determine the effect of topical pretreatment with isoproterenol and prostaglandin E2 on gastric mucosal injury induced by low concentrations of bile acid in shocked and normotensive rats. Mucosal injury was assessed by measuring net transmucosal ion fluxes (H+,K+) and luminal accumulation of DNA (DNAE), a sensitive and specific indicator of gastric mucosal cell exfoliation. In this model of mucosal injury, pretreatment with prostaglandin E2 or isoproterenol significantly and dose dependently decreased luminal hydrogen loss, potassium gain, and DNA accumulation in both shocked and normotensive animals. Thus, both topical prostaglandin E2 and isoproterenol reduce gastric mucosal injury caused by low concentrations of bile acid in shocked and normotensive rats, findings corroborated by histology. These findings provide a physiologic basis for the possible use of these agents as prophylaxis or treatment of stress gastritis and gastroduodenal ulcer in the critically ill patient.