Karl Pope - Academia.edu (original) (raw)

Papers by Karl Pope

Dermatologic Surgery, 2006

Lasers in Surgery and Medicine, 2005

Background and Objective: To determine the efficacy and safety of the ThermaCool 1 TC radiofreque... more Background and Objective: To determine the efficacy and safety of the ThermaCool 1 TC radiofrequency system for treatment of hypertrophic and keloid scars and evaluate treatment associated collagen changes. Materials and Methods: Six subjects with hypertrophic and four with keloid scars were treated with the Therma-Cool 1 device: one-third of the scar received no treatment (control), one-third received one treatment and one-third received two treatments (4-week interval). Scars were graded before and then 12 and 24 weeks after treatment on symptoms, pigmentation, vascularity, pliability, and height. Biopsies were taken from four subjects with hypertrophic scars and evaluated with hematoxylin and eosin (H & E) staining, multiphoton microscopy, and pro-collagen I and III immunohistochemistry. Results: No adverse treatment effects occurred. Clinical and H & E evaluation revealed no significant differences between control and treatment sites. Differences in collagen morphology were detected in some subjects. Increased collagen production (type III > type I) was observed, appeared to peak between 6 and 10 weeks posttreatment and had not returned to baseline even after 12 weeks. Conclusion: Use of the Thermage radiofrequency device on hypertrophic scars resulted in collagen fibril morphology and production changes. ThermaCool 1 alone did not achieve clinical hypertrophic scar or keloid improvement. The collagen effects of this device should be evaluated further in order to optimize its therapeutic potential for all indications.

Proceedings of SPIE, Jun 27, 2003

This study presents a finite element model of a non-ablative RF tissue heating system for dermato... more This study presents a finite element model of a non-ablative RF tissue heating system for dermatological applications. The Thermage ThermaCool TC System consists of a capacitively coupled treatment tip, handpiece, RF generator, and cryogen delivery system. Various electrode geometries were created to generate uniform thermal profiles at specific depths in the tissue. The optimal thermal treatment depth for a clinical indication is influenced by factors such as tissue thickness for a given anatomical location, the desired target for heating in that tissue, and anesthesia factors. Electrodes of ¼, 1, and 1½cm2 area were evaluated for depth of treatment. A 3D multi-physics finite element model was developed to simulate RF heating in tissue. The program coupled electrical and thermal models to predict the electric field produced and the consequent heating. The electrical portion of the model was verified using an electric field mapping system. The thermal section of the model was confirmed via thermocouple measurements for cooling and infrared imaging measurements for RF heating. The FEM model produced electrical and thermal predictions that were verified with experimental measurements. The finite element model shows significant potential as a predictive R&D tool to assist in RF electrode design and reduce product development time.

C45. EFFECTS OF THE ENVIRONMENT ON PULMONARY HEALTH, 2019

Gene, 1986

We have synthesized, cloned, and expressed the coding region for the C-terminal 159 amino acids (... more We have synthesized, cloned, and expressed the coding region for the C-terminal 159 amino acids (aa) of the human active interleukin polypeptide hormone IL-la. The sequence was assembled in stages and includes preferred Escherichia coli codons and unique restriction sites. The coding region was cloned on a multicopy plasmid vector adjacent to signals for transcription and translation that directed synthesis of 6 % of total E. cali protein as IL-la. Active IL-la mutants that have a C-terminal additional eleven aa and that have N-terminal deletions of six and fourteen aa are described. Plasmids expressing /I-galactosidase fusion proteins with various parts of IL-lc(at their N-termini were constructed.

Demand-Driven Innovation means understanding customers in poor communities and paying attention t... more Demand-Driven Innovation means understanding customers in poor communities and paying attention to the channels that move goods and services to these markets. Demand-Driven Innovation (DDI) requires a shi in thinking about how to tackle global poverty. It challenges commonly held assumptions about the needs and wants of poor communities, integrates information from customers into the design and development of products and services, and calls for careful consideration of how to reach these underserved markets. For many years, the international development community has been criticized for its lack of on-the-ground impact. Now donors must answer hard questions, such as: How many people are actually using the products and services we've spent so many decades and dollars creating? Why aren't we reaching more people? In the elds of health, agriculture, energy, education, water, and sanitation, many innovations have enormous potential. For example, mobile phone services inform sma...

NeuroToxicology, 2019

Automotive technicians are commonly exposed to organic and chlorinated solvents, particularly thr... more Automotive technicians are commonly exposed to organic and chlorinated solvents, particularly through use of cleaning products. Mainly during the period 1989 to 2002, n-hexane was a component of some of these products. In other occupational contexts, n-hexane has been shown to be a cause of peripheral neuropathy. The purpose of the present study was to investigate whether previous exposures to low concentrations of n-hexane were a cause of persistent peripheral neuropathy in automotive technicians. Enrolled in the study were 830 San Francisco Bay Area automotive technicians. Each participant underwent a battery of tests to investigate peripheral nervous system impairment. Test results regressed against estimated hexane and total solvent exposures showed only limited evidence of association with solvent exposures. Exposures to both hexane and general solvents were well below their occupational exposure limits. Generally, our results provide reassurance about persistent peripheral neuropathic effects in automotive technicians who previously used hexane-containing automotive cleaning products. This may reflect repair processes, since the exposures occurred some years previous to the study. However, we cannot exclude the possibility that the absence of observed effect in this study may be attributable to low exposures, exposure misclassification and/or the healthy worker survivor effect.

Journal of the American College of Nutrition, 2017

Background: Myofascial pain that has been associated with cancer and increased risk of morbidity ... more Background: Myofascial pain that has been associated with cancer and increased risk of morbidity and mortality in cancer patients is intrinsically associated with low magnesium and low 25-hydroxyvitamin D (25(OH)D). Therefore, this physical finding was used as a clinical diagnostic proxy. Objective: The objective of this study was to assess the association and prevalence of disease in individuals with myofascial pain and low 25(OH)D in a county with low magnesium in the drinking water. Design: This is a retrospective cross-sectional study of a chart review of 269 subjects to assess subjects presenting with myofascial pain (assessed by tender trigger points) and 25(OH)D concentrations below 30 ng/mL or a history of 25(OH)D deficiency compared to those without these exposures. Results: The association between the exposure of low 25(OH)D levels and myofascial pain was compared to all cancers, colon polyps, and tendon ruptures. The odds of having cancer with the combined exposures was 10.14 times the odds of not having either exposure (95% confidence interval [CI], 5.08, 20.25, p < 0.001). For adenomatous colon polyps, the odds ratio (OR) was 7.24 (95% CI, 3.83, 13.69, p < 0.001), and for tendon rupture, the OR was 8.65 (95% CI, 3.76, 19.94, p < 0.001). Of 80 subjects who had both myofascial pain and 25(OH)D less than 30 ng/mL, 74 were tested for red blood cell (RBC) magnesium. Half of those subjects had RBC magnesium concentrations < 4.6 mg/dL, and 23% had levels below the reference range (4.0-6.4 mg/dL). Conclusion: Myofascial pain as assessed by tender trigger points and 25(OH)D deficiency showed a significant association with cancer, adenomatous colon polyps, and tendon rupture. Further studies to verify these results are needed, especially in areas where there is low magnesium in the drinking water.

Neurotoxicology, 2017

The mechanism of toxicity of hydrogen sulfide (H2S) gas is thought mainly to operate through effe... more The mechanism of toxicity of hydrogen sulfide (H2S) gas is thought mainly to operate through effects on the nervous system. The gas has high acute toxicity, but whether chronic exposure causes effects, including peripheral neuropathy, is yet unclear. The city of Rotorua, New Zealand, sits on an active geothermal field and the population has some of the highest measured ambient H2S exposures. A previous study in Rotorua provided evidence that H2S is associated with peripheral neuropathy. Using clinical methods, the present study sought to investigate and possibly confirm this association in the Rotorua population. The study population comprised 1635 adult residents of Rotorua, aged 18-65. Collected data relevant to the peripheral neuropathy investigation included symptoms, ankle stretch reflex, vibration sensitivity, as measured by the timed-tuning fork test and a Bio-Thesiometer (Bio-Medical Instrument Co., Ohio), and light touch sensitivity measured by monofilaments. An exposure me...

deposition, water condensation and frost formation is studied in relationship to cooling rate and... more deposition, water condensation and frost formation is studied in relationship to cooling rate and efficiency of cryogen spray cooling (CSC) in combination with laser dermatologic surgery. Study Design/Materials and Methods: A high-speed video camera was used to image the surface of human skin during and after CSC using a commercial device. The influence of ambient humidity on heat extraction dynamics was measured in an atmosphere-controlled chamber using an epoxy block with embedded thermo-couples. Results: A layer of liquid cryogen may remain on the skin after the spurt termination and prolong the cooling time well beyond that selected by the user. A layer of frost starts forming only after the liquid cryogen retracts. Condensa-tion of ambient water vapor and subsequent frost forma-tion deposit latent heat to the target site and may significantly impair the CSC cooling rate. Conclusion: Frost formation following CSC does not usually affect laser dosage delivered for therapy of sub-...

for cooling human skin during various laser treatments. Since characteristics of such sprays have... more for cooling human skin during various laser treatments. Since characteristics of such sprays have not been com-pletely understood, the optimal atomizing nozzle design and operating conditions for cooling human skin remain to be determined. Materials and Methods: Two commercial cryogenic spray nozzles are characterized by imaging the sprays and the resulting areas on a substrate, as well as by measurements of the average spray droplet diameters, velocities, temperatures, and heat transfer coef®cients at the cryogen-substrate interface; all as a function of dis-tance from the nozzle tip. Results: Size of spray cones and sprayed areas vary with distance and nozzle. Average droplet diameter and velocity increase with distance in the vicinity of the nozzle, slowly decreasing after a certain maximum is reached. Spray temperature decreases with distance due to the extraction of latent heat of vaporization. At larger distances, tem-perature increases due to complete evaporation of spray dro...

La presente invention concerne divers procedes et systemes permettant de proceder a un traitement... more La presente invention concerne divers procedes et systemes permettant de proceder a un traitement cutane par rayonnement impliquant un refroidissement dynamique de tissus, ces procedes et systemes etant egalement destines a minimiser ou a prevenir toute apparition d'eclats lumineux au cours dudit traitement.

L'invention concerne un procede de traitement d'un site de tissus qui consiste a coupler ... more L'invention concerne un procede de traitement d'un site de tissus qui consiste a coupler une surface de distribution d'energie d'un dispositif de distribution d'energie electromagnetique a une surface de la peau. Une zone de tissus sous-jacents situee sous la surface de la peau est creee. Le refroidissement cree un gradient thermique inverse, selon lequel une temperature de la surface de la peau est inferieure a une temperature de la zone de tissus sous-jacents. L'energie est distribuee depuis ledit dispositif de distribution d'energie electromagnetique a ladite zone de tissus sous-jacents. La distribution d'energie modifie la zone de tissus sous-jacents et reduit les irregularites de la surface de la peau.

Zoonoses and Public Health, 2021

This case–control study sought to confirm and investigate in more depth protective associations p... more This case–control study sought to confirm and investigate in more depth protective associations previously found of bovine (cattle and water buffalo) ownership with reduced risk of both pulmonary tuberculosis (PTB) and latent tuberculosis infection (LTBI) in humans. The study recruited male and female PTB cases from a diagnostic centre and a frequency‐matched community‐based control group in Kaski District, Nepal. Controls were tested for LTBI status and a separate nested case–control study was conducted based on LTBI status. Data were collected on participant household animal ownership. Using logistic regression, animal ownership was investigated for associations with both PTB and LTBI. Data were obtained from 570 PTB cases and 1,224 controls, the latter group providing 396 LTBI‐positive and 692 LTBI‐negative subjects. Results provided evidence of decreased odds of both PTB and LTBI positivity associated with owning bovines. The evidence was strongest for protection against infection, rather than activation of infection to PTB. Effects were strongest in women, who usually manage the animals in Nepal, and there were exposure‐response relationships with numbers of bovines owned. Results suggest that exposure to bovines is protective against LTBI and PTB. A possible mechanism involves boosting the effect of BCG (Bacillus Calmette‐Guerin) vaccination, particularly in protecting against tuberculous infection. Additional studies with more extensive data collection are needed to confirm the observed associations.

Global Heart, 2020

Background: Exposure to household air pollution (HAP) from cooking with biomass fuel affects bill... more Background: Exposure to household air pollution (HAP) from cooking with biomass fuel affects billions of people. We hypothesized that HAP from woodsmoke, compared to other household fuels, was associated with adverse cardiovascular outcomes, of which there have been few studies. Methods: A cross-sectional study was completed in 299 females aged 40-70 years in Kaski District, Nepal, during 2017-18. All participants underwent a standard 12-lead ECG, ankle and brachial systolic blood pressure measurement, and 2D color and Doppler echocardiography. Current stove type was confirmed by inspection. Blood pressure, height, and weight were measured using a standardized protocol. Hypertension was defined as ≥140/90 mmHg or prior diagnosis. Hemoglobin A1c (HbA1c) was obtained, with diabetes mellitus defined as a prior diagnosis or HbA1C ≥ 6.5%. We used adjusted linear and logistic multivariable regressions to examine the relationship of stove type with cardiac structure and function. Results: The majority of women primarily used liquified petroleum gas (LPG) stoves (65%), while 12% used biogas, and 23% used wood-burning cook-stoves. Prevalence of major cardiovascular risk factors was 35% with hypertension, 19% with diabetes mellitus, and 15% current smokers. After adjustment, compared to LPG, wood stove use was associated with increased indexed left atrial volume (β = 3.15, 95% CI 1.22 to 5.09) and increased indexed left ventricular end diastolic volume (β = 7.97, 95% CI 3.11 to 12.83). There was no association between stove type and systemic hypertension, left ventricular mass, systolic dysfunction, diastolic dysfunction, pulmonary hypertension, abnormal ankle-brachial index, or clinically significant ECG abnormalities. Conclusion: Biomass fuel use was associated with increased indexed left atrial volume and increased indexed left ventricular diastolic volume in Nepali women, suggesting subclinical adverse cardiac remodeling from HAP in this cross-sectional study. We did not find evidence of an association with hypertension or typical cardiac sequelae of hypertension. Future studies to confirm these results are needed.

Environmental Research, 2019

Optometry and Vision Science, 2017