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Biomedical subjects

R A Peters

Publications and source records attributed to R A Peters.

At least 19 recordsLinked to original sources
PubMed1997

The management of high-grade hilar strictures by endoscopic insertion of self-expanding metal endoprostheses.

BACKGROUND AND STUDY AIMS: Treatment options for unresectable hepatic hilar strictures include percutaneous or endoscopic stent insertion, using either standard Teflon or self-expanding metal endoprostheses. The use of Teflon stents is complicated by stent migration and high occlusion rates. Published series of endoscopically placed metal stents have not concentrated on their use in the treatment of high-grade hilar strictures (Bismuth grades II and III). We therefore undertook a prospective and open pilot study to evaluate the efficacy of endoscopically placed metal endoprostheses in the palliation of jaundice due to high-grade hilar strictures. PATIENTS AND METHODS: Self-expanding metal stents were placed endoscopically in 17 patients (nine women, eight men; median age 64 years, range 33-77). Of the 17 malignancies 11 patients (65%) had a diagnosis of cholangiocarcinoma, and 12 (71%) had Bismuth grade III strictures. RESULTS: The stents were inserted successfully in all 1 patients. Adequate drainage, as demonstrated by a significant reduction in bilirubin, was achieved in 1: (88%); the two patients in whom drainage failed had extensive intrahepatic disease. Early complications (cholangitis) developed in one patients (6%), and there were seven late complications (41%) in five patients (four occluded stents and three cases of duodenal compression). The stent patency appeared to be prolonged (median stent patency 12 months, range 1.5-24 months, in patients surviving five months or more). The median survival was ten months (range 1-48 months) after stent insertion. All of the patients died during follow-up. CONCLUSIONS: These results suggest that endoscopically placed metal stents offer effective palliation for high grade hilar malignancies, although controlled trial comparing the use of metal and Teflon endoprostheses in this patient group are required.

Bile Duct Neoplasms↗
PubMed1996

Randomised study of endoscopic biliary endoprosthesis versus duct clearance for bileduct stones in high-risk patients.

BACKGROUND: The value of an endoprosthesis for long-term management of bileduct stones has not been formally established. The main theoretical advantage of endoprosthesis insertion (BE) over conventional endoscopic duct clearance (DC) is the prevention of stone impaction, with obstruction and consequent cholangitis or pancreatitis. In a randomised study we compared the results of these two methods in patients with symptomatic bileduct stones who were at high risk because of old age (> 70 yr) or serious debilitating disease. METHODS: 43 high-risk patients were randomised to BE with a 7F double-pigtail endoprosthesis and < 0.75 cm sphincterotomy, and 43 to DC with standard 1.25-1.50 cm sphincterotomy and stone extraction by balloon or basket, with or without mechanical lithotripsy. The principal endpoint was the rate of biliary related complications. FINDINGS: In the BE group biliary drainage was achieved in the first session in all but one patient (who required 2 sessions). In the DC group, 24 patients had duct clearance at the first attempt and 35 (81%) after a median of 2 sessions (range 2-4); eight of this group had an endoprosthesis inserted to maintain long-term drainage. At 72 h the complication rates were 7% in the BE group and 16% in the DC group (p = 0.18). However, the long-term complication rate for BE was higher: by Kaplan-Meier analysis, at a median of 20 months the proportions free of biliary complications were 64% BE and 86% DC (p = 0.03, log-rank test). INTERPRETATION: For immediate bileduct drainage, endoprosthesis insertion proved a safe and effective alternative to duct clearance. Because of the risk of subsequent cholangitis, its use as a definitive treatment should be confined to highly selected cases.

Aged↗
PubMed1994

Thrombin--an effective treatment for gastric variceal haemorrhage.

The optimum treatment of gastric varices has still to be defined. Lesser curve gastric varices may be treated by injection sclerotherapy, but this has a limited role in the treatment of fundal gastric varices. Surgical intervention is commonly needed but carries a high mortality in patients with advanced liver disease. This study evaluated the use of thrombin for the treatment of gastric varices in 11 consecutive patients (nine with fundal, two with high lesser curve varices), identified as having bled from this site. Bovine thrombin (1000 U/ml) was injected intravariceally (mean volume 5.5 ml, range 2-10 ml) producing initial haemostasis in all 11 cases. Varices were considered thrombosed or obliterated in all patients after a median of two injection episodes (range 1-3). After a median follow up of nine months only one patient had rebled from a gastric varix. Thrombin may represent a valuable alternative injectate for the treatment of gastric varices.

Acute Disease↗
PubMed1994

Primary amyloidosis and severe intrahepatic cholestatic jaundice.

Liver involvement in systemic amyloidosis is frequent but is rarely of clinical importance. Five patients with severe cholestatic jaundice are described and an additional 20 from published reports are reviewed. The most frequent presenting symptoms were lethargy and abdominal pain, which were present for a median of 11 months before the onset of jaundice. Hepatomegaly, usually marked, was present in 92%, with ascites in 56% of the cases. The serum bilirubin concentration was noticeably high and the serum globulin low. Histology of the liver showed considerable perisinusoidal deposition with a slight predilection for the periportal area. Two patients presented with predominant centrilobular deposition. Congo red staining was not uniformly positive. A variety of treatment regimens was tried but median survival was only three months from the onset of jaundice.

Aged↗
PubMed1991

Automatic measurements of fetal long bones. A feasibility study.

We investigated whether it would be possible for a computer to propose values for measurements commonly obtained (femur and humerus) during obstetrical sonography. In this preliminary study, the images were scanned and analyzed off-line using morphological operators. The procedure described allowed us to measure the long bones and has a very high coefficient of correlation with measurements obtained by humans. Ideally, the whole procedure could probably be part of the computer instructions that are built into the machine.

Algorithms↗
PubMed1988

The influence of resident surgical training on outcome of carotid endarterectomy in a teaching hospital.

Eighty-two consecutive patients who underwent 101 consecutive carotid endarterectomies (CEA) between 1982 and the first half of 1986 were evaluated. All of the operations were performed by fourth and fifth year general surgical residents under direct staff supervision. Hemispheric symptoms were present in 75 percent, and 64 per cent had a stenosis of 70 per cent or greater. In 24 per cent of the CEA, the indication for operation was a completed stroke. The operative stroke rate was 3 per cent and the mortality rate, 1 per cent. At a mean follow-up period of 17.4 months, no strokes had occurred, and the restenosis rate was 4 per cent over-all and 1 per cent in primary simple CEA. These results of CEA in a teaching hospital are excellent and indicate no compromise in patient care related to resident surgeons performing the procedures.

Carotid Artery Diseases↗
PubMed1981

Subacute fluoroacetate poisoning.

Fluoroacetic acid and some other monofluoro-compounds are among the most poisonous substances known. In man symptoms of poisoning begin after a latent period of one-half to several hours and death follows rapidly. Convulsions and arrhythmia are common terminal signs. No specific changes have been found at postmortem. It is suggested, but unproven, that sudden death of the patient whom this case report concerns was due to subacute fluoroacetate poisoning.

Adult↗
PubMed1980

Ether-O-oxidase.

Explore the source record for details and available documents.

Animals↗
PubMed1977

Further observations on an ether-O-oxidase, formerly called alkyl etherase, from liver tissue.

1. The microsomal enzyme from liver previously called an "etherase" is now described more accurately as an ether-O-oxidase. It has been investigated further to free it from the membranes in aqueous solution and to try to define its physiological substrate. 2. After a variety of attempts with detergents, etc., the enzyme was obtained in impure solution from precipitation with 35-45% (NH4)2SO4 solution after a short digestion at room temperature. 3. When a suitably reinforced the enzyme in solution forms citrate from added ethyl ether, as it does in membranous form. This indicates the intermediary formation of acetyl CoA. 4. The enzyme in solution is unstable, though some activity remains after standing at 0degrees C for 2-3 days. Activity is lost rapidly by deep freezing, exposure to 2M-NaCl and at a pH more acid than pH 5-0. 5. The enzyme does not appear to be a known oxidase obtainable from liver microsomes; it is not for instance part of the inducible mixed oxygenase system, nor a peroxidase or catalase. 6. Since there were some similarities in stability with enzymes dealing with protozoal plasmalogens, or with lanosterol or cholesterol, we were led to explore these substrates in detail, with negative results. But a specimen of cholesterol oxidase from the branching bacterium Nocardia gave O-oxidation with diethylether. 7. The enzyme is present in the livers of all four animals examined, namely the rat, pig, guinea-pig and pigeon, but not in kidney or brain. 8. The enzyme takes up O2 with some compounds containing O-me groups. 9. The hypothesis is advanced that this normal oxidase in liver membranes exists to deal with some substances from plant sources which might prove toxic upon entering the circulation.

Animals↗
PubMed1977

Intraoral extranodal Hodgkin's disease.

A case of extranodal Hodgkin's disease that was limited to the maxillary alveolus has been presented. A team approach was used to diagnose and treat the lesion. After appropriate staging procedures, treatment consisted of local excision and cobalt teletherapy. Follow-up examinations for the past three years have failed to disclose recurrent or new disease.

Aged↗
PubMed1976

A technique for open reduction of subcondylar fractures.

Described is a safe and efficient technique for open reduction of the subcondylar fracture. The technique utilizes a Risdon incision to expose the fracture site and a stab incision in the preauricular region. A University of Tennessee drill guide or bone screw is introduced through the stab incision to facilitate placement of drill holes in the fragments, threading of the transosseous wires, and repositioning of the condyle within the fossa.

Fracture Fixation↗
PubMed1975

An alkyl etherase in rat liver.

1. Diethyl ether, which is known to be partly metabolized in vivo, has been found to show an O2 uptake with the rat liver microsomal membranes; a similar reaction is given with other short chain aliphatic ethers, isoproply and n-butyl ether. 2. The "etherase" reaction is optimal at pH 7.2-7.4 and is not accompanied by an increased formation of malondialdehyde. 3. When CoA is added to the microsomes together with a source of oxaloacetate and the consensing enzyme synthase, the etherase present forms citrate from diethyl ether, indicating an acetylation of CoA, which then enters the citric acid cycle. 4. Similarly to 3, fluorocitrate is formed from methyl fluoroethyl ether. 5. Differing from plasmalogens, a tetrahydropteridine does not have to be added as a co-factor.

Acetylation↗