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Biomedical subjects

A F Jones

Publications and source records attributed to A F Jones.

96 records · Page 6Linked to original sources
PubMed1979

Growth-stimulating factor in regenerating canine liver.

Extracts from dog livers which had been regenerating for 24, 48, and 72 h after hepatectomy were infused for 6 h into the left portal vein of animals which had fresh portacaval shunts (Eck fistula) and which were killed 2 and 3 days later. The brief exposure to the 48-h and especially the 72-h regenerating liver extracts induced a delayed proliferative response predominantly in the left liver lobes, with a slight spillover effect to the right liver lobes but none to the kidney. The response reached its peak 3 days later. In the left but not the right liver lobes, both the 48-h and the 72-h regenerating liver extract reversed the atrophy ordinarily caused by Eck fistula in 3 days and partly prevented the ultrastructural hepatocyte deterioration characteristic of Eck fistula. The active liver extracts apparently contained a growth-control factor or factors which is (are) not insulin or glucagon.

Animals↗
PubMed1979

Immediate operation for ectopia cordis.

Forty-one infants with thoracoabdominal ectopia cordis have been reported to date; 9 of them survived. Among the patients with an omphalocele as the abdominal wall defect, however, only 2 survived. Death in this group of patients occurred almost exclusively as a consequence of either attempted coverage of the heart or secondary to the associated intracardiac lesion. We report here the case of a patient recently treated in whom coverage with a temporary Silastic prosthesis protected the exposed heart from infection and rupture of the sac, thus permitting full cardiac investigation before operation.

Abdominal Muscles↗
PubMed1978

The effect of splanchnic viscera removal upon canine liver regeneration.

The influence of portal blood factors on canine liver regeneration was studied with graded nonhepatic splanchnic evisceration, coupled with 44 and 72 per cent hepatectomies. In one type of experiment, the pancreas was retained while the rest of the intra-abdominal gastrointestinal tract was removed. In a second variety, total pancreatectomy was performed with preservation of the intra-abdominal organs. In a third kind of experiment, total nonhepatic splanchnic evisceration was performed. Liver regeneration after hepatectomy was decreased by all three kinds of viscera removed as judged by deoxyribonucleic acid synthesis, autoradiography and mitotic index. Pancreatectomy and nonpancreatic splanchnic evisceration caused almost equal decreases in the regenerative response. Total nonhepatic splanchnic evisceration essentially halted regeneration during the first three postoperative days and intraportal infusions of insulin or glucagon, or both together, did not reverse this effect. The decrease in liver membrane bound adenyl cyclase activity and biphasic change in liver cyclic 3', 5' -adenosine monophosphate concentrations normally seen after partial hepatectomy were disrupted after the various eviscerations. Adenyl cyclase activity and cyclic 3', 5' -adenosine monophosphate concentrations tended to be higher than normal in the eviscerated dogs. These observations provide more support for our previously proposed hypothesis that control of liver regeneration is by multiple factors. Pancreatic hormones are important modifiers of this response but, by no means, exercise exclusive control. Other substances of gastrointestinal origin, presumably including hormones and nutrient supply apparently play important specific roles. The volume of portal flow is a secondary and nonspecific, but possibly significant, factor.

Adenylyl Cyclases↗
PubMed1978

Cyclic AMP metabolism and adenylate cyclase concentration in patients with advanced hepatic cirrhosis.

Glucagon was tested for its effect on plasma adenosine 3',5'-cyclic monophosphate (cyclic AMP), insulin, and glucose in healthy subjects and in patients with advanced cirrhosis of the liver. In the normal subjects, intravenous infusion of glucagon caused a significant increase in plasma cyclic AMP, glucose, and insulin. In advanced cirrhotics, plasma cyclic AMP, glucose, and insulin did not increase. Adenylate cyclase concentration was measured in liver tissue from end stage cirrhotic patients and from brain-dead organ donors whose cardiovascular function was maintained in a stable state. Basal and total adenylate cyclase concentration were not different in the two groups. Adenylate cyclase from the livers of advanced cirrhotics was, however, significantly less responsive to glucagon stimulation than was that from donor livers. Hepatocytes in advanced cirrhosis have abnormal metabolic behavior characterized by abnormal adenylate cyclase-cyclic AMP response to hormonal stimulation.

Adenylyl Cyclases↗
PubMedDate not supplied

Increased diene conjugates in diabetic subjects with microangiopathy.

Free radicals are highly reactive unstable chemical species which have been implicated in the vascular damage associated with several disease states. Diene conjugates, probable products of free radical activity on lipids, were measured spectrophotometrically in 26 diabetic patients with microangiopathy, 36 uncomplicated diabetic patients, and 36 healthy controls. Total diene conjugates and diene conjugate to triglyceride ratios were significantly elevated in diabetic patients with microangiopathy (0.57 +/- 0.08 and 0.31 +/- 0.14 OD units/ml respectively; mean +/- SD) when compared with patients without complications (0.32 +/- 0.10, p less than 0.001, and 0.17 +/- 0.06, OD units/ml, p less than 0.011). There was no difference in total diene conjugation and their ratio to triglycerides between healthy controls and uncomplicated diabetic patients and the results were not influenced by the type of diabetes or level of diabetic control. Diene conjugate ratios repeated in 14 patients on two occasions, 6 weeks apart, with stable metabolic control were consistent. Increased diene conjugation suggesting increased free radical activity is associated with microangiopathy and this may have pathogenetic implications.

Adult↗