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Biomedical subjects

T G Wilson

Publications and source records attributed to T G Wilson.

At least 127 records · Page 7Linked to original sources

Isolation and characterization of pteridines from heads of Drosophila melanogaster by a modified thin-layer chromatography procedure.

An improved thin-layer chromatography technique is described for the separation of fluorescent compounds found in extracts of heads of Drosophila melanogaster. Eighteen to twenty fluorescent spots are resolved, two of which are xanthurenic acid and 3-hydroxykynurenine, and the remaining spots are presumably pteridines. Of these, nine have been identified and quantitated directly on the chromatograms with a fluorometer. One of the spots present on the chromatogram apparently has not been described previous to this work. Characteristics of this substance, termed "quench spot," are presented, several of which indicate that it may be a pteridine or pteridine derivative.

Animals↗

Mechanism of suppression in Drosophila. V. Localization of the purple mutant of Drosophila melanogaster in the pteridine biosynthetic pathway.

The suppressible eye color mutant purple (pr) of Drosophila melanogaster is known to be unable to synthesize a wild-type complement of pteridine eye pigments. This study measures the reduced levels of drosopterins, sepiapterin, and an unidentified presumed pteridine in pr and prbw. Pteridine analyses in double mutants combining pr with one of three other eye color mutants sepia, Henna-recessive3, and prune2, suggest that the metabolic block in pr occurs prior to sepiapterin biosynthesis. Measurements of GTP and GTP cyclohydrolase in pr showed wild-type levels and indicate the metabolic block in pr to be at one of the steps converting dihydroneopterin triphosphate to sepiapterin. Quantitation of pteridines in suppressed purple [su(s)2; pr and pr; su(pr)e3] shows restoration of pteridines to wild-type or nearly wild-type levels.

Aging↗

Men in nursing.

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New Zealand↗

Joseph Toynbee.

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England↗

Sir Astley Cooper.

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General Surgery↗

Minimizing the risk of bile duct injury at laparoscopic cholecystectomy.

The introduction of laparoscopic cholecystectomy (LC) has been associated with an increase in the incidence of operative bile duct injuries. An operative technique that involves commencing the laparoscopic dissection on the body of the gallbladder and dissecting toward the cystic duct has been developed that minimizes the risk of major duct injury. The aim of this study was to assess prospectively the safety of this dissection technique. A group of 410 patients underwent LC for symptomatic cholelithiasis from January 1991 to December 1992. There was a single common hepatic duct injury: a small (1 mm) side hole in a patient with acute cholecystitis and choledocholithiasis. It was managed at open operation with exploration of the common bile duct and insertion of a T-tube. There were no partial or complete common bile duct transections in this series. We concluded that the technique of commencing the dissection on the gallbladder is safe and minimizes the risk of serious common bile duct injury at LC.

Bile Ducts↗

Percutaneous cystogastrostomy with a new catheter for drainage of pancreatic pseudocysts and fluid collections.

We describe a new catheter for the initial percutaneous drainage of large symptomatic pancreatic fluid collections and abscesses using a transgastric approach to allow fluid drainage into the gastric lumen. A double-mushroom stent is placed secondarily for long-term internal drainage to the stomach, avoiding the need for an extended period of external catheter drainage. This technique, termed percutaneous cystogastrostomy (PCG), has been used in 19 consecutive patients with one recurrent symptomatic pseudocyst in the follow-up period fo 9-43 months. There was one death within 30 days of PCG and 1 patient proceeded to surgical necrosectomy. After evidence of resolution of the pseudocysts, the internal stent was retrieved in 17 patients by endoscopic snare.

Abscess↗

Prospective randomized comparison of open versus laparoscopic appendectomy in men.

A prospective, randomized trial was performed to compare open appendectomy with laparoscopic appendectomy in men with a clinical diagnosis of acute appendicitis. Sixty-four patients with a median age of 25 years (range 18-84 years) were randomized to open appendectomy (n = 31) or laparoscopic (n = 33) appendectomy. Of the 64 men, 56 (87.5%) had appendicitis (27 open, 29 laparoscopic procedures). The mean operating times were 50.6 +/- 3.7 minutes (+/- SEM) for open and 58.9 +/- 4.0 minutes for laparoscopic appendectomy (p = 0.13). Five (15%) patients randomized to laparoscopic appendectomy had an open operation. The mean postoperative hospital stay was significantly longer for open appendectomy (3.8 +/- 0.4 days) than for laparoscopic appendectomy (2.9 +/- 0.3 days) (t = 2. 05,df = 62,p = 0.045). The complication rate after open appendectomy (25.8%) was not significantly different from that after laparoscopic appendectomy (12.1%). There was a single postoperative death due to a pulmonary embolus in the laparoscopic group and a single death due to cardiac and renal failure in the open group. The mean time to return to normal activities was significantly longer following open appendectomy (19.7 +/- 2.4 days) than after laparoscopic appendectomy (10.4 +/- 0.9 days), (t = 3.75,df = 49,p = 0.001). In conclusion, laparoscopic appendectomy in men has significant advantages in terms of a more rapid recovery compared to open appendectomy. There were no significant disadvantages to laparoscopic appendectomy compared to open appendectomy.

Adolescent↗

Stress-reactivity and juvenile hormone degradation in Drosophila melanogaster strains having stress-related mutations.

Juvenile hormone (JH) degradation was studied under normal and stress conditions in young and matured females of Drosophila melanogaster strains having mutations in different genes involved in responses to stress It was shown that (1) the impairment in heat shock response elicits an alteration in stress-reactivity of the JH system; (2) the impairment JH reception causes a decrease of JH-hydrolysing activity and of stress-reactivity in young females, while in mature ones stress reactivity is completely absent; (3) the absence of octopamine results in higher JH-hydrolysis level under normal conditions and altered JH stress-reactivity; (4) the higher dopamine content elicits a dramatic decrease of JH degradation under normal conditions and of JH stress-reactivity. Thus, the impairments in any component of the Drosophila stress reaction result in changes in the reponse of JH degradation system to stress. The role of JH in the development of the insect stress reaction is discussed.

Animals↗