Farhad Navab - Academia.edu (original) (raw)
Papers by Farhad Navab
PubMed, Oct 1, 1985
Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leu... more Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leukocyte scan and 10 patients with negative scan showed no significant difference between the two groups for the Crohn's disease activity index, sedimentation rate, survival, complications, number of days in hospital, outpatient visits, or readmissions. Despite the apparent lack of statistical significance in Crohn's disease activity index, the scan was positive in nine of 16 patients with a Crohn's disease activity index more than 150, and none of three patients with Crohn's disease activity index less than 150. In the patients studied, there were no false-positive leukocyte scans. In nine of 10 patients with ileocolonic disease, scanning results correctly predicted the proper management. Six patients with positive scan and enteroclysis responded to medical treatment. Four patients had positive enteroclysis and negative scan; of these, three had radiographic features of chronic ileal stricture which was confirmed at operation. The results suggest that a negative delayed indium-111 leukocyte scan may be useful in diagnosis of chronic fibrotic ileal stricture.
PubMed, Nov 1, 1995
Objectives: Large gastric folds may result from infectious, inflammatory, neoplastic, vascular, a... more Objectives: Large gastric folds may result from infectious, inflammatory, neoplastic, vascular, and infiltrative disorders involving a part or the entire gastric wall. Helicobacter pylori infection of the gastric mucosa is associated with an active gastritis characterized by infiltration of the mucosa and submucosa with neutrophils, eosinophils, macrophages, and lymphocytes. The purposes of the study were: 1) to study patients with large gastric folds noted on computed tomography, upper gastrointestinal series, or endoscopy, with endoscopy and biopsies and endoscopic ultrasound to determine the prevalence of H. pylori infection and the location of the thickening within the gastric wall; 2) to reexamine H. pylori-infected patients with EUS after antimicrobial therapy to determine whether resolution of the wall thickening accompanied eradication of H. pylori and improvement of histological gastritis. Methods: Thirty-two patients with thickened gastric folds were studied. Eighteen patients had H. pylori infection and were treated with amoxicillin 1 g b.i.d. and omeprazole 40 mg b.i.d. x 14 days. One month after antimicrobial therapy, patients were reexamined by EUS, and gastric biopsies were obtained. Results: Eighteen of 32 patients had H. pylori infection and gastritis. In the H. pylori-infected patients with gastritis, EUS demonstrated diffuse thickening of the inner three layers (mucosa-lumen interface, deep mucosa, submucosa) without thickening of the 4th and 5th layers of the gastric wall. After antimicrobial therapy and resolution of gastritis, EUS demonstrated concomitant resolution of this thickening and normalization of layers 1-3. Conclusions: H. pylori gastritis is a common cause of gastric wall thickening. EUS allows intrinsic localization of the gastric wall thickening in patients with large gastric folds and H. pylori infection and documents the resolution of this wall thickening upon eradication of H. pylori and resolution of gastritis.
Radiology, 1986
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precise... more The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Muller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large-and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.
The New England Journal of Medicine, Jun 12, 1997
The American journal of gastroenterology, 1995
Recent observations have suggested that stress ulcer prophylaxis should not routinely be used to ... more Recent observations have suggested that stress ulcer prophylaxis should not routinely be used to prevent upper gastrointestinal hemorrhage in critically ill patients. This is because our understanding of stress ulcer pathogenesis has shifted from a problem limited to back diffusion of acid to a phenomenon of gastric ischemia. The purpose of this article is to review the proposed mechanism of stress ulcer bleeding and to discuss prophylaxis.
Gut, Mar 1, 1970
S U M MARY Serum concentrations of ,B-alanine and L-histidine are compared in five normal adults ... more S U M MARY Serum concentrations of ,B-alanine and L-histidine are compared in five normal adults after ingestion of the dipeptide carnosine (/-alanyl-L-histidine) and after equivalent amounts of the constituent free amino acids. The results indicate that absorption is significantly more rapid after the ingestion ofthe amino acids than after the dipeptide. The use of the test in a case of Hartnup disease suggests that carnosine is taken up by intestinal cells as the dipeptide, but subsequent hydrolysis and delivery of the constituent amino acids to the portal blood is a slower process than transport of the free amino acids themselves.
Gut, May 1, 1970
A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nic... more A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nicotinamide. This supports the view that all the clinical features, except reduced stature from general nutritional defect, are secondary to tryptophan and nicotinamide deficiency rather than to an unknown toxic factor. Severe malabsorption of both tryptophan and phenylalanine was demonstrated. The dipeptide carnosine was absorbed normally whereas when the two constituent amino acids, f-alanine and L-histidine, were ingested, absorption of the former was normal but that of the latter was grossly defective. The suggestion is advanced that in cases of Hartnup disease protein nutrition is maintained by intestinal uptake of amino acids as oligopeptides rather than as free amino acids. By contrast, both modes of absorption are probably important in normal subjects. Radiology of the small intestine is abnormal
The Lancet, Sep 1, 1980
Everson (July 19, p. 123) suggests that persons exposed transplacentally to tobacco carcinogens m... more Everson (July 19, p. 123) suggests that persons exposed transplacentally to tobacco carcinogens may be at increased cancer risk. This prompted us to examine our data on women smokers and cancer rates of children and young adults among the several ethnic groups living in Hawaii. The data on smoking were obtained by personal interviews of over 5000 women, selected as a representative population sample of the State during 1975-76. The cancer incidence rates were obtained using data from the Statewide population-based Hawaii Tumor Registry, in operation since 1960. In the table, we present the ethnic-specific age and sex adjusted cancer incidence rates for all sites combined for persons age 0-24 during 1973-77. Also presented are the ethnic-specific, ageadjusted percentages of women smokers, age 18-64 during 1975-76. This age-range was chosen to include all women who would be likely to have offspring age 0-24 during 1973-77.
Clinical Science, 1971
1. The uptake of l-methionine and glycine as free amino acids, and from their dipeptides by evert... more 1. The uptake of l-methionine and glycine as free amino acids, and from their dipeptides by everted rings of rat small intestine in vitro has been investigated. The concentrations used covered a wide range, including values likely to be near those found in the lumen of the intestine. 2. Though no intact peptides were found in the mucosal cells, evidence was obtained which showed that hydrolysis of the peptides was cellular at all concentrations. Total hydrolysis of peptides by the intestine was very great in relation to amino acid uptake over very short incubation times, suggesting that much hydrolysis took place superficially. 3. Except at the lowest concentrations, the rates of uptake of amino acids from the peptides were more rapid than from the equivalent amino acid mixtures. Competition for uptake between glycine and methionine was avoided when they were presented in the form of l-methionylglycine. 4. Anoxia inhibited uptake of methionine from free l-methionine and from l-methi...
Gut, 1970
Asatoor, 1970). The disease, therefore, provides an almost unique opportunity for the study of th... more Asatoor, 1970). The disease, therefore, provides an almost unique opportunity for the study of the importance of intestinal absorption of oligopeptides in man. This paper describes tests of absorption of two dipeptides and of the corresponding amino acids in a patient suffering from Hartnup disease and in normal control subjects. Methods The methods used in this investigation were not ideal, but were conditioned by the following difficulties. Oligopeptides are difficult to prepare in bulk and commercial samples are extremely expensive. Throughout the investigation, therefore, a compromise had to be adopted using the minimum dose of oligopeptide which would be expected to give an increase of plasma amino acids sufficient in amount to avoid appreciable experimental error.
Southern Medical Journal, 1984
An analysis of the records of 300 patients who had had 370 small-bowel radiologic examinations an... more An analysis of the records of 300 patients who had had 370 small-bowel radiologic examinations and a subsequent 102 patients examined by fluoroscopy and enteroclysis suggests that enteroclysis (small-bowel enema) is extremely valuable in the radiologic evaluation of small intestinal disease. Our results suggest that best results are obtained if the radiologist spends adequate time to participate in and observe the studies carefully. We believe that the fluoroscopic observation of low-density barium passing through distended small bowel gives a much clearer picture of its status than routine follow-through examinations. Disagreement exists concerning the choice of Sellink's method, using dilute barium, and Herlinger's technique, using a somewhat denser barium followed by methylcellulose. We prefer the latter. Enteroclysis probably should not be done in the presence of a high small-bowel obstruction because of the danger of reflux and aspiration. If intubation is unsuccessful, an oral study should be postponed until the effects of the topical anesthesia disappear. A controlled prospective study of the accuracy of fluoroscopic enteroclysis versus a good detailed independent follow-through examination is needed.
Abstract: Objective: Sleeping on the right side (right lateral decubitus position) is associated ... more Abstract: Objective: Sleeping on the right side (right lateral decubitus position) is associated with increased acid reflux. It is unknown how sleep position during young adulthood affects patients with Barrett's Esophagus (BE), a precursor to esophageal adenocarcinoma. Material and Methods: This retrospective study examined 58 adult men enrolled from 2001 to 2008 with a new diagnosis of BE who did not have esophageal adenocarcinoma or prior esophageal or gastric surgery. Detailed medical history included questions on sleep position during young adulthood (age 19-29). Quantile regression was used for multivariable adjustment. Results: The median age at presentation was 55 with a range of 33-91. 28 patients (48.3%) had BE lengths of at least 3 cm. Most patients (69.0%) reported sleeping on their right side only. Sleep position was associated with the age at presentation (p = 0.009). Patients who slept on their left side were the oldest at diagnosis (adjusted median age = 68.7 ye...
Gut, 1970
A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nic... more A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nicotinamide. This supports the view that all the clinical features, except reduced stature from general nutritional defect, are secondary to tryptophan and nicotinamide deficiency rather than to an unknown toxic factor. Severe malabsorption of both tryptophan and phenylalanine was demonstrated. The dipeptide carnosine was absorbed normally whereas when the two constituent amino acids, f-alanine and L-histidine, were ingested, absorption of the former was normal but that of the latter was grossly defective. The suggestion is advanced that in cases of Hartnup disease protein nutrition is maintained by intestinal uptake of amino acids as oligopeptides rather than as free amino acids. By contrast, both modes of absorption are probably important in normal subjects. Radiology of the small intestine is abnormal
The American journal of gastroenterology, 1985
Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium... more Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leukocyte scan and 10 patients with negative scan showed no significant difference between the two groups for the Crohn's disease activity index, sedimentation rate, survival, complications, number of days in hospital, outpatient visits, or readmissions. Despite the apparent lack of statistical significance in Crohn's disease activity index, the scan was positive in nine of 16 patients with a Crohn's disease activity index more than 150, and none of three patients with Crohn's disease activity index less than 150. In the patients studied, there were no false-positive leukocyte scans. In nine of 10 patients with ileocolonic disease, scanning results correctly predicted the proper management. Six patients with positive scan and enteroclysis responded to medical treatment. Four patients had positive enteroclysis and negative scan; of these, three had radiographic features o...
The Journal of the Arkansas Medical Society, 1982
PubMed, Oct 1, 1985
Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leu... more Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leukocyte scan and 10 patients with negative scan showed no significant difference between the two groups for the Crohn's disease activity index, sedimentation rate, survival, complications, number of days in hospital, outpatient visits, or readmissions. Despite the apparent lack of statistical significance in Crohn's disease activity index, the scan was positive in nine of 16 patients with a Crohn's disease activity index more than 150, and none of three patients with Crohn's disease activity index less than 150. In the patients studied, there were no false-positive leukocyte scans. In nine of 10 patients with ileocolonic disease, scanning results correctly predicted the proper management. Six patients with positive scan and enteroclysis responded to medical treatment. Four patients had positive enteroclysis and negative scan; of these, three had radiographic features of chronic ileal stricture which was confirmed at operation. The results suggest that a negative delayed indium-111 leukocyte scan may be useful in diagnosis of chronic fibrotic ileal stricture.
PubMed, Nov 1, 1995
Objectives: Large gastric folds may result from infectious, inflammatory, neoplastic, vascular, a... more Objectives: Large gastric folds may result from infectious, inflammatory, neoplastic, vascular, and infiltrative disorders involving a part or the entire gastric wall. Helicobacter pylori infection of the gastric mucosa is associated with an active gastritis characterized by infiltration of the mucosa and submucosa with neutrophils, eosinophils, macrophages, and lymphocytes. The purposes of the study were: 1) to study patients with large gastric folds noted on computed tomography, upper gastrointestinal series, or endoscopy, with endoscopy and biopsies and endoscopic ultrasound to determine the prevalence of H. pylori infection and the location of the thickening within the gastric wall; 2) to reexamine H. pylori-infected patients with EUS after antimicrobial therapy to determine whether resolution of the wall thickening accompanied eradication of H. pylori and improvement of histological gastritis. Methods: Thirty-two patients with thickened gastric folds were studied. Eighteen patients had H. pylori infection and were treated with amoxicillin 1 g b.i.d. and omeprazole 40 mg b.i.d. x 14 days. One month after antimicrobial therapy, patients were reexamined by EUS, and gastric biopsies were obtained. Results: Eighteen of 32 patients had H. pylori infection and gastritis. In the H. pylori-infected patients with gastritis, EUS demonstrated diffuse thickening of the inner three layers (mucosa-lumen interface, deep mucosa, submucosa) without thickening of the 4th and 5th layers of the gastric wall. After antimicrobial therapy and resolution of gastritis, EUS demonstrated concomitant resolution of this thickening and normalization of layers 1-3. Conclusions: H. pylori gastritis is a common cause of gastric wall thickening. EUS allows intrinsic localization of the gastric wall thickening in patients with large gastric folds and H. pylori infection and documents the resolution of this wall thickening upon eradication of H. pylori and resolution of gastritis.
Radiology, 1986
The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precise... more The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Muller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large-and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.
The New England Journal of Medicine, Jun 12, 1997
The American journal of gastroenterology, 1995
Recent observations have suggested that stress ulcer prophylaxis should not routinely be used to ... more Recent observations have suggested that stress ulcer prophylaxis should not routinely be used to prevent upper gastrointestinal hemorrhage in critically ill patients. This is because our understanding of stress ulcer pathogenesis has shifted from a problem limited to back diffusion of acid to a phenomenon of gastric ischemia. The purpose of this article is to review the proposed mechanism of stress ulcer bleeding and to discuss prophylaxis.
Gut, Mar 1, 1970
S U M MARY Serum concentrations of ,B-alanine and L-histidine are compared in five normal adults ... more S U M MARY Serum concentrations of ,B-alanine and L-histidine are compared in five normal adults after ingestion of the dipeptide carnosine (/-alanyl-L-histidine) and after equivalent amounts of the constituent free amino acids. The results indicate that absorption is significantly more rapid after the ingestion ofthe amino acids than after the dipeptide. The use of the test in a case of Hartnup disease suggests that carnosine is taken up by intestinal cells as the dipeptide, but subsequent hydrolysis and delivery of the constituent amino acids to the portal blood is a slower process than transport of the free amino acids themselves.
Gut, May 1, 1970
A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nic... more A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nicotinamide. This supports the view that all the clinical features, except reduced stature from general nutritional defect, are secondary to tryptophan and nicotinamide deficiency rather than to an unknown toxic factor. Severe malabsorption of both tryptophan and phenylalanine was demonstrated. The dipeptide carnosine was absorbed normally whereas when the two constituent amino acids, f-alanine and L-histidine, were ingested, absorption of the former was normal but that of the latter was grossly defective. The suggestion is advanced that in cases of Hartnup disease protein nutrition is maintained by intestinal uptake of amino acids as oligopeptides rather than as free amino acids. By contrast, both modes of absorption are probably important in normal subjects. Radiology of the small intestine is abnormal
The Lancet, Sep 1, 1980
Everson (July 19, p. 123) suggests that persons exposed transplacentally to tobacco carcinogens m... more Everson (July 19, p. 123) suggests that persons exposed transplacentally to tobacco carcinogens may be at increased cancer risk. This prompted us to examine our data on women smokers and cancer rates of children and young adults among the several ethnic groups living in Hawaii. The data on smoking were obtained by personal interviews of over 5000 women, selected as a representative population sample of the State during 1975-76. The cancer incidence rates were obtained using data from the Statewide population-based Hawaii Tumor Registry, in operation since 1960. In the table, we present the ethnic-specific age and sex adjusted cancer incidence rates for all sites combined for persons age 0-24 during 1973-77. Also presented are the ethnic-specific, ageadjusted percentages of women smokers, age 18-64 during 1975-76. This age-range was chosen to include all women who would be likely to have offspring age 0-24 during 1973-77.
Clinical Science, 1971
1. The uptake of l-methionine and glycine as free amino acids, and from their dipeptides by evert... more 1. The uptake of l-methionine and glycine as free amino acids, and from their dipeptides by everted rings of rat small intestine in vitro has been investigated. The concentrations used covered a wide range, including values likely to be near those found in the lumen of the intestine. 2. Though no intact peptides were found in the mucosal cells, evidence was obtained which showed that hydrolysis of the peptides was cellular at all concentrations. Total hydrolysis of peptides by the intestine was very great in relation to amino acid uptake over very short incubation times, suggesting that much hydrolysis took place superficially. 3. Except at the lowest concentrations, the rates of uptake of amino acids from the peptides were more rapid than from the equivalent amino acid mixtures. Competition for uptake between glycine and methionine was avoided when they were presented in the form of l-methionylglycine. 4. Anoxia inhibited uptake of methionine from free l-methionine and from l-methi...
Gut, 1970
Asatoor, 1970). The disease, therefore, provides an almost unique opportunity for the study of th... more Asatoor, 1970). The disease, therefore, provides an almost unique opportunity for the study of the importance of intestinal absorption of oligopeptides in man. This paper describes tests of absorption of two dipeptides and of the corresponding amino acids in a patient suffering from Hartnup disease and in normal control subjects. Methods The methods used in this investigation were not ideal, but were conditioned by the following difficulties. Oligopeptides are difficult to prepare in bulk and commercial samples are extremely expensive. Throughout the investigation, therefore, a compromise had to be adopted using the minimum dose of oligopeptide which would be expected to give an increase of plasma amino acids sufficient in amount to avoid appreciable experimental error.
Southern Medical Journal, 1984
An analysis of the records of 300 patients who had had 370 small-bowel radiologic examinations an... more An analysis of the records of 300 patients who had had 370 small-bowel radiologic examinations and a subsequent 102 patients examined by fluoroscopy and enteroclysis suggests that enteroclysis (small-bowel enema) is extremely valuable in the radiologic evaluation of small intestinal disease. Our results suggest that best results are obtained if the radiologist spends adequate time to participate in and observe the studies carefully. We believe that the fluoroscopic observation of low-density barium passing through distended small bowel gives a much clearer picture of its status than routine follow-through examinations. Disagreement exists concerning the choice of Sellink's method, using dilute barium, and Herlinger's technique, using a somewhat denser barium followed by methylcellulose. We prefer the latter. Enteroclysis probably should not be done in the presence of a high small-bowel obstruction because of the danger of reflux and aspiration. If intubation is unsuccessful, an oral study should be postponed until the effects of the topical anesthesia disappear. A controlled prospective study of the accuracy of fluoroscopic enteroclysis versus a good detailed independent follow-through examination is needed.
Abstract: Objective: Sleeping on the right side (right lateral decubitus position) is associated ... more Abstract: Objective: Sleeping on the right side (right lateral decubitus position) is associated with increased acid reflux. It is unknown how sleep position during young adulthood affects patients with Barrett's Esophagus (BE), a precursor to esophageal adenocarcinoma. Material and Methods: This retrospective study examined 58 adult men enrolled from 2001 to 2008 with a new diagnosis of BE who did not have esophageal adenocarcinoma or prior esophageal or gastric surgery. Detailed medical history included questions on sleep position during young adulthood (age 19-29). Quantile regression was used for multivariable adjustment. Results: The median age at presentation was 55 with a range of 33-91. 28 patients (48.3%) had BE lengths of at least 3 cm. Most patients (69.0%) reported sleeping on their right side only. Sleep position was associated with the age at presentation (p = 0.009). Patients who slept on their left side were the oldest at diagnosis (adjusted median age = 68.7 ye...
Gut, 1970
A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nic... more A severely affected case ofHartnup disease is reported,where the patient responded rapidly to nicotinamide. This supports the view that all the clinical features, except reduced stature from general nutritional defect, are secondary to tryptophan and nicotinamide deficiency rather than to an unknown toxic factor. Severe malabsorption of both tryptophan and phenylalanine was demonstrated. The dipeptide carnosine was absorbed normally whereas when the two constituent amino acids, f-alanine and L-histidine, were ingested, absorption of the former was normal but that of the latter was grossly defective. The suggestion is advanced that in cases of Hartnup disease protein nutrition is maintained by intestinal uptake of amino acids as oligopeptides rather than as free amino acids. By contrast, both modes of absorption are probably important in normal subjects. Radiology of the small intestine is abnormal
The American journal of gastroenterology, 1985
Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium... more Comparison of nine patients with Crohn's disease who had a positive delayed (24 hr) 111indium leukocyte scan and 10 patients with negative scan showed no significant difference between the two groups for the Crohn's disease activity index, sedimentation rate, survival, complications, number of days in hospital, outpatient visits, or readmissions. Despite the apparent lack of statistical significance in Crohn's disease activity index, the scan was positive in nine of 16 patients with a Crohn's disease activity index more than 150, and none of three patients with Crohn's disease activity index less than 150. In the patients studied, there were no false-positive leukocyte scans. In nine of 10 patients with ileocolonic disease, scanning results correctly predicted the proper management. Six patients with positive scan and enteroclysis responded to medical treatment. Four patients had positive enteroclysis and negative scan; of these, three had radiographic features o...
The Journal of the Arkansas Medical Society, 1982