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Biomedical subjects

A R Dennison

Publications and source records attributed to A R Dennison.

At least 91 records · Page 5Linked to original sources
PubMed1987

Absorptive and motor function of orthotopically vascularized segmental ileal autografts.

In 24 dogs a 100 cm length of terminal ileum was autografted as an orthotopically vascularized Thiry-Vella segment. In six dogs absorption, motility and histology were studied in detail and in two intestinal myo-electrical activity was recorded. At a second operation 5 weeks after autotransplantation the Thiry-Vella segment was returned to its normal anatomical position in the intestinal stream and 2 months later all the non-transplanted intestine was resected. Eighteen grafts were technically successful. Intestinal myo-electrical activity was normal by the second day after transplantation while intestinal transit and contractile activity recovered within 10 days. Mucosal morphology and intestinal absorption had largely recovered by 10 days after grafting but absorption of oleic acid was impaired for 4 weeks. Ten dogs with severe short, bowel syndrome but intact ileocaecal valve were maintained in good health for more than 7 months by a 100 cm ileal autograft.

Animals↗
PubMed1987

Use of a lipid containing medium chain triglycerides in patients receiving TPN: a randomized prospective trial.

Lipid emulsions which contain long chain triglycerides (LCTs) provide a valuable energy source for patients requiring total parenteral nutrition (TPN). We have investigated the use of a new lipid emulsion containing both long and medium chain triglycerides (MCTs) in a randomized prospective trial. Sixty patients received TPN including 500 ml of either 20 per cent Lipofundin S (LCT) or Lipofundin 10 per cent MCT/10 per cent LCT for at least 6 days. Patients with renal or hepatic impairment, or major trauma, were excluded from the study. The MCT/LCT emulsion was found to be as safe and as effective a source of calories as LCT but the differences in metabolic parameters did not differ significantly between the two groups of patients. A lipid emulsion containing MCTs may have important advantages for seriously ill patients, but appears to have no obvious advantages for the majority of patients receiving TPN who are not severely stressed.

Adult↗
PubMed1987

Segmental small intestinal allografts in the dog. I. Morphological and functional indices of rejection.

Fourteen dogs received an orthotopically vascularized allograft of a 100-cm length of terminal ileum as a Thiry-Vella segment. Absorption, motility, myoelectrical activity and morphology of the allograft were studied to determine the most reliable indices of rejection. The earliest histological evidence of rejection occurred at a mean of 6.2 +/- 0.9 days and was coincident with significant deterioration in the absorption of water, alanine, lauric acid, sodium, and glucose. Intestinal motility did not decrease until 7-8 days after transplantation, and intestinal myoelectrical activity was unchanged for a further 2-3 days, by which time graft necrosis was imminent. Reduced intestinal motility occurs only after rejection is established, and is therefore of little use as an index of rejection, while recording intestinal myoelectrical activity is valueless and serves only to confirm graft death. Decreased intestinal absorption of water, sodium, glucose, alanine, and lauric acid are present as early as the first changes in mucosal histology and are useful indices of rejection of intestinal allografts.

Animals↗
PubMed1987

Segmental small intestinal allografts. II. Inadequate function with cyclosporine immunosuppression: evidence of a protein-losing enteropathy.

Terminal ileum was autografted (24 dogs) or allografted (18 dogs) as a 100-cm Thiry-Vella segment, and absorption, motility, and histology were studied. Dogs with allografts were given cyclosporine (CsA) 20 mg/kg/day. At a second operation 5 to 6 weeks after transplantation continuity of the nontransplanted intestine with the Thiry-Vella segment was restored. At a third operation 3 months after autografting, all the non-transplanted small intestine was excised. All technically successful autografts survived indefinitely, and the dogs weights were maintained at 88 +/- 0.6% (mean +/- SE) of preoperative weights by absorption from the autografted intestine. Administration of cyclosporine to dogs with intestinal autografts produced a reversible impairment of intestinal absorption. Dogs with allografts survived 63.3 +/- 15.5 days (mean +/- SE). Death within 9 weeks of transplantation was from peritonitis secondary to graft rejection. Death in long survivors was a consequence of inadequate intestinal absorption. In the first 4 weeks after transplantation absorption and motility of allografted Thiry-Vella segments was comparable to the intestinal autografts but allografts showed evidence of a protein losing enteropathy. Large volumes of high protein-content fluid were lost from the allografted Thiry-Vella segments, and dogs with allografts became hypoalbuminemic.

Animals↗
PubMed1986

Varicocele and varicose veins compared. A basis for logical surgery.

In the past only large symptomatic varicoceles were treated surgically, but this has changed now that they are believed to be a cause for infertility. Ten patients have been studied using the Doppler flowmeter and phlebography to compare varicoceles and varicose veins in the legs and to decide whether or not the same principles apply in their surgical treatment. These studies have confirmed a similar mechanism of retrograde flow from above a pumping mechanism to below it. Surgery must aim at effective and complete interruption of the source of the downflow. This requires ligation of the testicular vein either at sufficiently high level to insure that it is above any major branches or that these are included in the ligation. There is no danger of causing venous obstruction because a varicocele would not develop without the existence of a massive alternative venous outlet.

Humans↗
PubMed1986

The metabolic consequences of infusing emulsions containing medium chain triglycerides for parenteral nutrition: a comparative study with conventional lipid.

In order to test the hypothesis that medium chain triglycerides (MCT's) are a safe and potentially superior energy source during parenteral nutrition 13 patients were entered into a randomised cross over trial. They received either a long chain triglyceride emulsion (LCT) or a 50% medium chain (MCT)/50% LCT mixture as part of their energy supply. Nitrogen balance was significantly better when MCT/LCT was infused and the greater levels of plasma ketones and lower plasma triglyceride levels suggested that MCT was more readily metabolised in these patients. Routine haematology, biochemistry and liver function tests gave no indication of harmful side effects from MCT.

Adult↗
PubMed1985

Simple mastectomy under local anaesthesia.

Nine patients with locally advanced carcinoma of the breast underwent simple mastectomy under regional anaesthesia (1% lignocaine and 1:100,000 adrenaline). Preoperative sedation was provided by oral lorazepam. There were no technical problems, evidence of lignocaine toxicity or excessive operative blood loss and no wounds became infected.

Aged↗
PubMed1984

What has happened to perforated peptic ulcer?

The number of elective operations for chronic peptic ulceration has decreased substantially with the widespread use of H2-receptor antagonists. We have reviewed all cases of perforated peptic ulcer in Oxford over the last 18 years (1965-82) to see if a similar change in the incidence of this major complication of peptic ulceration has occurred. Since 1976 there has been a fall in the incidence of perforated peptic ulcer from 8.7 to 6.9 cases per 100 000 population per year. The male to female ratio decreased over the review period from 4.9:1 to 1.9:1 owing to a reduced incidence of perforation in men and an increased incidence in women. The mean age of men with perforated duodenal ulcer increased from 52.3 years in 1965-70 to 59.0 years in 1977-82. One hundred and sixty-six patients treated between 1977 and 1982 have been reviewed in detail. The overall mortality in this 6 year period was 12.7 per cent with an operative mortality rate of 8.9 per cent. The majority of perforations (65 per cent) are now of acute ulcers and therefore are unlikely to be prevented by improved therapy for chronic peptic ulceration.

Aged↗
PubMed1984

Sigmoid volvulus: new thoughts on the epidemiology.

Sigmoid volvulus usually affects the elderly, but it is being increasingly described in a younger age group. In these patients the diagnosis is often delayed, due to a prolonged and intermittent history. Three patients, of 31,36, and 67 years, are described here, and they demonstrate an increased incidence within families, which has not been previously recognized. Awareness of this possibility may allow earlier diagnosis when investigating young patients with intermittent abdominal symptoms, whose relatives are known to be affected.

Adult↗
PubMedDate not supplied

Augmenting the ablative effect of liver electrolysis: using two electrodes and the pringle maneuver.

Several methods of liver tumor ablation have been investigated, and these include the novel technique of electrolysis. Electrolysis is slower than other forms of ablative therapy. This study determined methods of increasing the ablative effect of electrolysis. Domestic white pigs were divided. One group received electrolysis using two electrode catheters, and in the other group a concurrent intermittent Pringle maneuver was performed to induce intermittent ischemia. The effect of two electrode catheters versus a single electrode catheter was compared, and the effect of the Pringle maneuver versus no Pringle was examined with two electrode catheters. The livers were harvested, and the volume of each lesion was calculated. There was a linear relationship between the volume of hepatic necrosis and the electrolytic dose in (p <.005) in both the single-electrode-catheter and two-electrode-catheter groups. Comparison between the single- and multiple-electrode groups showed a highly significant difference in the dose response (p <.0000002) when more than one electrode was used. Use of the Pringle maneuver during electrolysis produced larger volumes of hepatic necrosis over all doses when using two electrode catheters. Rates of necrosis were 3.8 cm(3)/100 C for a single electrode catheter, 5.46 cm(3)/100 C for two electrode catheters without Pringle, and 6.17 cm(3)/100 C for electrolysis with two electrode catheters coupled with intermittent Pringle maneuver. Thus, electrolysis was both reliable and predictable in producing hepatic necrosis in a dose-dependent manner. The time delay in achieving tumor ablation via electrolysis can be overcome by using two electrodes combined with the Pringle maneuver to increase the volume of the lesion produced.

Animals↗