Biomedical subjects
Publications and source records attributed to R C Bowyer.
Failure to detect a pneumothorax may have serious complications. A case of a pneumothorax, which may have been overlooked if thoracic computed tomography had not been performed, is discussed.
Malignant stromal tumours of the duodenum are rare. The efficacy of surgical resection for duodenal leiomyosarcoma was assessed in 5 patients treated over an 11-year period, probably the largest series treated by a single surgeon. There were 3 women and 2 men with an age range of 27-52 years. Tumours were large (8.5-21 cm diameter) and partly cystic (4 cases). They arose from the second (2), third (2) and fourth parts of the duodenum. Resection was a major undertaking and comprised either partial duodenectomy (n = 4) or Whipple resection. Two patients required a right hemicolectomy in addition. Two patients with positive resection margins had adjuvant radiotherapy. Operative time ranged from 4.0 to 6.25 h and blood loss from 1.8 to 4.5 litres. Two patients developed complications: a transient low-output biliary fistula and an infected haematoma requiring percutaneous drainage. The 2 patients with incomplete resection died of recurrent disease at 3 and 15 months. The 3 survivors are free of disease at 24, 60 and 66 months. The results support a policy of aggressive resection despite the technical difficulties posed by these large and vascular tumours.
Explore the source record for details and available documents.
This study of thyroid histopathological data from hospitals in the South West Thames region was undertaken to assess current practice and the scope for improvement. Over a 6 month period, 186 thyroid operations were performed on 179 patients at eight hospitals serving almost 1.7 million people. The frequency of thyroidectomy in different hospitals varied from 13 to 35 per 100,000 per year and 6.4% of the operations were second thyroidectomies. Benign multinodular goitre was the most common histological finding (34%). A benign solitary nodule was found in 36% and malignancy in 8.4% of the specimens. Correlation of histological analysis and type of operation suggested that a variety of operations were performed for the same pathological condition and that some operations were diagnostic procedures only. Overall, 63 of the 186 operations (34%) might have been avoided by a firm preoperative diagnosis. Only 67 thyroid fine needle aspiration biopsies (FNAC) were performed at the eight hospitals during the study period. Only 15 (8%) of the patients who underwent thyroid operation had been investigated by FNAC. Reduction in thyroid surgery through more widespread use of FNAC could result in savings of 100,000 pounds per million population per year. Regional activity data show that more than 50 surgeons currently undertake a workload of less than 500 thyroidectomies each year. Increased subspecialisation may be required to reduce costs and raise standards.
Explore the source record for details and available documents.
As efforts to curtail costs in surgical practice increase, we have attempted to identify savings that might be achieved by altering knot tying techniques. Instrument-tied knots utilise less suture material than do hand-tied knots. This may translate into a significant annual cost reduction.
Enterostatin, the procolipase activation peptide, has been suggested in previous studies to act as a satiety signal for food intake, with a specificity for fat intake. In this study, by use of a competitive enzyme-linked immunosorbent assay with a detection limit of 4.115 nmol/L and within 6% intra- and interassay variation, the immunoreactive and chromatographic characterization of enterostatin in intestinal content was undertaken in Sprague-Dawley rats. Following intravenous infusion of cholecystokinin octapeptide (CCK-8; 200 pmol/kg/h) for 60 min, the concentration of intestinal enterostatin increased from a basal level of 2.0 +/- 0.7 microM to 5.64 +/- 1.1 microM at time point 60 min. The enterostatin level remained at 4.24 +/- 0.54 microM for 120 min after the CCK infusion had ceased. Pancreatic lipase and colipase activities in rat intestinal content also increased during the CCK-8 infusion. The enzyme activities reached the maximal level after 30 min of CCK infusion and thereafter progressively decreased to basal levels, remaining there during the following 2 h. The basal level of intestinal enterostatin in rats fed with standard pellets was found to be increased from 1.42 +/- 0.14 to 3.86 +/- 0.4, 3.17 +/- 0.54, and 5.02 +/- 1.6 microM on days 1, 3, and 7, respectively, after high-fat feeding. Parallel to the increase in intestinal enterostatin, there was a significant increase in pancreatic lipase and colipase activities in the intestine during the ingestion period of high-fat diet as compared with the control group. The estimated molecular mass of enterostatin immunoreactivity of intestinal content was similar to that of the synthetic pentapeptide. These results suggest that immunoreactive enterostatin (Val-Pro-Gly-Pro-Arg) is normally present in rat intestinal content, is significantly increased after stimulation with CCK-8, and is also increased after prolonged high-fat feeding.
Cystogastrostomy or cystojejunostomy at open operation has been the usual treatment for symptomatic pancreatic pseudocyst. The aim of this study was to assess prospectively the results of percutaneous cystogastrostomy (PCG) for the treatment of symptomatic pseudocysts. The technique of PCG comprised initially of drainage of the pseudocyst with a 10 Fr percutaneous, transgastric catheter. This initial drainage catheter had two components; the first, between the pseudocyst and the stomach, drained the pseudocyst and the second, between the stomach and exterior, acted as a percutaneous gastrostomy. The initial drain was left in situ for 14 days, at which time it was exchanged percutaneously for the definitive PCG; a double ended Mallecot type catheter that drained between the pseudocyst and the stomach. The latter catheter was left in situ until there was no residual pseudocyst demonstrated on computerized tomography scan and was removed endoscopically. Eleven patients with large (> 6 cm), symptomatic pseudocysts have been treated with PCG. All patients were treated successfully without the need for surgical intervention. The median time to radiological resolution was 24 days. There were four episodes of sepsis, two related to central venous line infections nad two related to catheter blockage. Percutaneous, cystogastrostomy blockage was managed by either replacing the initial drain or inserting a second catheter. The median follow up after successful treatment was 9 months (range 2-17). There were no symptomatic recurrences and one small (2 cm) asymptomatic recurrent pseudocyst. This preliminary experience with PCG demonstrates the efficacy of this procedure for treating symptomatic pancreatic pseudocysts.
The effect of a satiating meal on the serum and urinary concentrations of procolipase propeptide (Ala-Pro-Gly-Pro-Arg, APGPR) immunoreactivity, as measured by enzyme linked immunosorbent assay (ELISA) specific for free APGPR, has been studied in normal and morbidly obese human subjects. The normal subjects displayed a biphasic response with coordinate increases in both serum and urine APGPR immunoreactivity both occurring within the first two hours after the meal. In two of three of the morbidly obese subjects, this early rise in APGPR concentration in urine was not seen but was followed by a slow rise in urinary APGPR immunoreactivity at four to six hours. In both the normal and obese groups, the urinary immunoreactive signal was found to coelute with synthetic APGPR on gel chromatography. In rats, procolipase propeptide (Val-Pro-Asp-Pro-Arg, VPDPR) specifically inhibits fat intake early in the postprandial period when given peripherally or centrally. This study suggests that in humans APGPR reaches the circulation shortly after feeding and is excreted in the urine. These findings are consistent with the hypothesis that human procolipase propeptide may also act as a satiety signal. In addition the late appearance of the peptide in some of the morbidly obese patients could be associated with perturbation of appetite control in these subjects.
It has been suggested that surgery for abdominal aortic aneurysm (AAA) be confined to designated centres. A prospective audit of 200 consecutive AAA repairs at a district general hospital was performed between 1981 and 1990. The 30-day mortality rates for elective, symptomatic and ruptured aneurysm repair were 1.4%, 3.5% and 30%, respectively. The major factor affecting outcome after the mode of presentation was the age of the patient, with 30-day mortality rates for emergency treatment increasing from 21% (age range 60-69 years) to 42% (age range 70-79 years). This mortality rate for ruptured aneurysms is an underestimate, with two-thirds of patients with rupture dying before reaching hospital and some patients dying in hospital undiagnosed. The major contribution to improved overall mortality would therefore be detection before rupture (usually by ultrasound) and improved diagnostic accuracy. Many patients with ruptured aneurysms had symptoms for only a short period before presentation (42% for less than 6 h) and required urgent surgery (26% reached theatre within 1 h). These two factors make long-distance transfer of these patients an unrealistic option. The concentration of this type of surgery in relatively few centres will distance the patient from their relatives and reduce the opportunity for the majority of junior doctors to acquire an understanding of the presentation, natural history and management of aortic aneurysms. This understanding when combined with a screening programme is likely to have a far greater impact on the overall mortality from AAA than restricting the centres for surgical treatment.
Human pancreatic colipase is secreted as the inactive form procolipase. Activation involves tryptic cleavage of an N-terminal pentapeptide Ala-Pro-Gly-Pro-Arg (APGPR) which is known as procolipase activation peptide (CLAP). N-terminally haptenised synthetic APGPR was used to generate specific C-terminally directed anti-APGPR antibodies. The antiserum was used to develop a competitive enzyme linked immunosorbent assay (ELISA) specific for free CLAP with a detection limit of 12 nmol/l and an intra-assay coefficient of variation (CV) of 3.28% and an inter-assay CV of 5.82%. The release of immunoreactive CLAP from human pancreatic juice and chicken pancreas upon trypsinisation was demonstrated, as well as the absence of reactivity of the antisera with procolipase from which the CLAP is released. APGPR was found to be unstable in biological fluids. Immunoreactivity is rapidly lost with half life of 5 min and 4 h in human serum and urine respectively. This loss of reactivity can be significantly slowed by the addition of 20 mmol/l Zinc ions (Zn2+), while ethylenediaminetetra-acetic acid (EDTA) and other protease inhibitors were ineffective. In serum the moiety responsible for loss of immunoreactivity was found to have an estimated molecular mass of 200,000-300,000 Da. CLAP assay specifically reports procolipase activation and may help elucidate the mechanism of satiety as well as contribute to the recognition and understanding of the role of procolipase activation in diseases states such as pancreatitis.
There are several forms of the enzyme phospholipase A2 (PLA2) in human tissues. In the pancreas the enzyme is produced as a zymogen, pro-phospholipase A2 (pro-PLA2). The active form is generated upon proteolytic cleavage of the N-terminal prophospholipase A2 activation peptide (PLAP), with the sequence Asp-Ser-Gly-Ile-Ser-Pro-Arg (DSGISPR). Antisera specific for free PLAP were produced by immunization with the synthetic peptide, N-terminally conjugated to bovine thyroglobin. Affinity purified antibodies were used to develop a radioimmunoassay with a detection limit of 5 nmol/L. Competitive inhibition studies with amino-terminally truncated sequences showed that, at least, the C-terminal pentapeptide (GISPR) was required for significant inhibition. Anti-PLAP antibodies did not react with native human pancreatic homogenate (a source of pro-PLA2). A large immunoreactive signal was generated upon trypsinization, which coeluted with synthetic PLAP when chromatographed on Sephadex-G25. Likewise, Sephadex-G50 chromatograph fractions of the untrypsinized homogenate reacted with the antibodies only after trypsinization. The immunoreactive signal appeared at a molecular weight of 14,500 which corresponds to the reported molecular weight of pancreatic pro-PLA2. This demonstrates that the assay is specific for the free peptide and reports pro-PLA2 activation. PLAP assay may therefore contribute to the study of the role of the PLA2 activation event in disease states such as pancreatitis.
Historical review shows that the treatment of popliteal aneurysm has developed by trial and error and there is disagreement about the proper management of the symptomless patient. In 1981 a policy of conservative management for asymptomatic popliteal aneurysm was adopted in this unit. Since that time we have also managed nine patients with thrombosed popliteal aneurysms by arteriography and low-dose intra-arterial streptokinase. Six patients treated within 72 h of occlusion achieved significant (70-100 per cent) lysis, but streptokinase was ineffective in those treated 10 or more days after the thrombosis. Of the six patients with significant lysis, three were treated by elective reconstruction and two by anticoagulation. One patient who had significant lysis died. Vascular patency of all five successfully treated limbs was maintained and no limb loss occurred in those who presented late and failed to achieve significant lysis. These results reinforce the view that thrombolysis is the treatment of choice for thrombosed popliteal aneurysms. The low complication rate for asymptomatic popliteal aneurysms and the advent of safe, effective thrombolysis indicate that operation for symptomless popliteal aneurysm is no longer required.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The relationships between urinary oxalate, calcium and magnesium were investigated in 81 patients with idiopathic calcium oxalate urolithiasis on their regular diets. A significant relationship was established between calcium and oxalate excretion in the analysis of recurrent stone-formers (n = 44, P less than 0.01), though there was no significant difference between the two in the analysis of the patients overall or in single stone-formers. This suggests that recurrent stone-formers may have some abnormality of oxalate absorption in relation to calcium absorption. The role of calcium-oxalate interaction in the gut as a cause of mild hyperoxaluria is discussed.
Explore the source record for details and available documents.
Explore the source record for details and available documents.