Biomedical subjects

S T West

Publications and source records attributed to S T West.

3 recordsLinked to original sources

PubMed2000

The effect of pantethine and ultraviolet-B radiation on the development of lenticular opacity in the emory mouse.

PURPOSE: Few studies have examined the impact of long-term treatments or exposures on the development of cataract in maturity-onset animal models. We studied the effect of treatment with D-pantethine and exposure to ultraviolet-B (UVB) radiation on the development of lenticular opacity in the Emory mouse. METHODS: A total of 164 Emory mice were randomized by litter at weaning to exposure to UVB light at 12 mJ/cm(2) for 6 hr/day (UV) or usual room light (A), and within litter, were further randomized to bi-weekly intra-peritoneal injections of 0.8 g/kg pantethine (T) or no treatment (C). Retro illumination lens photos were taken at 2, 4, 6, 8, and 10 months after weaning, and graded in masked fashion. The animals were sacrificed at 10 months and the lenses analyzed for total pantethine and total cysteamine. RESULTS: Lens pantethine and cysteamine levels were significantly (P < 0.001) higher for the T as compared to C litters. Mean cataract grade increased monotonically over time for all four groups. Unadjusted mean grade for the AT group at 8 (1.32) and 10 (1.86) months appeared lower than for the other groups (AC: 2.17, 2.39; UVC: 1.77, 2.40; UVT: 1.88, 2.37). However, the mean grade for the pantethine-treated litters did not differ significantly from the untreated litters except at 2 months (when untreated litters had significantly lower grades), when adjusting for UV treatment, gender and litter effect. No significant difference in cataract score existed between UV-exposed and ambient litters. Mortality was higher among pantethine-treated (hazard ratio = 1.8, p = 0.05) and UV-exposed animals (hazard ratio = 1.8, p = 0. 03) than among the untreated and unexposed litters. CONCLUSION: Significantly increased lens levels of pantethine are achieved with long-term intra-peritoneal dosing. The impact of pantethine on the progression of lenticular opacity in the Emory mouse is less than has been reported in other models. This level of chronic UVB exposure appeared to have no effect on the development of cataract in this model.

Animals↗

PubMed1993

Laparoscopy explosion hazards with nitrous oxide.

BACKGROUND: During laparoscopic surgery utilizing carbon dioxide as the insufflating agent, nitrous oxide will diffuse into the peritoneal cavity if it is used as part of the anesthetic. Bowel perforation and the subsequent release of volatile bowel gas could create a explosion hazard. METHODS: Two related studies were undertaken. The first quantified the transfer of nitrous oxide, over time, in 19 female patients undergoing laparoscopy. The second established the lower limits of flammability of a range of concentrations of methane and hydrogen diluted with nitrogen (simulated bowel gas) in a range of concentrations of nitrous oxide diluted with carbon dioxide (simulated peritoneal gas). RESULTS: The mean concentrations of N2O at 10, 20, and 30 min from the time of insufflation were 19.9 +/- 4.8%, 30.3 +/- 6.8%, and 36.1 +/- 6.9%, respectively. The maximum reported concentrations of methane and hydrogen in bowel gas are 56% and 69%, respectively. The concentration of nitrous oxide necessary to support combustion of 56% methane is approximately 47%. By contrast, the concentration of nitrous oxide needed to support combustion of 69% hydrogen is approximately 29%. CONCLUSIONS: The authors have shown that it is possible for nitrous oxide to reach concentrations in the peritoneal cavity that can support combustion of bowel gas.

Adult↗

PubMedDate not supplied

Successful term pregnancies after tubal anastomosis utilizing contralateral tubal segments.

In performing reversal of tubal sterilization, the microsurgeon sometimes has to face difficult anatomical situations due to extensive tubal damage, particularly after laparoscopic unipolar cauterization. In a recent case report, a technique of utilization of contralateral fallopian tube segments in tubal reanastomosis has been described. An intrauterine pregnancy followed, which resulted in a spontaneous abortion at 8 weeks' gestation. We report here our experience in ten cases utilizing a similar technique. Three patients achieved a term pregnancy. One patient achieved three intrauterine pregnancies that ended in first-trimester abortions. It is felt by the authors that this technique should be kept in mind by the practicing microsurgeon for selected cases.

Adult↗