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Biomedical subjects

G Claes

Publications and source records attributed to G Claes.

At least 55 records · Page 3Linked to original sources
PubMed1979

Successful kidney transplantation in a man with Dacron "trouser" prosthesis.

The case history of a male patient, 62 years old, in preterminal uremia at transplantation with a cadaveric kidney is described. Twelve years before the transplantation he was operated on because of an aortic aneurysm where the abdominal aorta and both iliac arteries were substituted with a Dacron prosthesis. The kidney was anastomosed to this vessel substitute and functioned excellently for more than five years and the patient was completely rehabilitated.

Aorta, Abdominal↗
PubMed1978

Collagenase isolation and 45Ca efflux studies of human islets of Langerhans.

22 human pancreases were removed soon after circulatory arrest from donors aged 15--63 years. Part of the pancreas was used for isolation of islets by the collagenase technique. The mean yield +/- SEM, expressed as the number of islets isolated from 4 g pancreas was 79 +/- 15. The yield varied considerably even when the pancreas was removed immediately after circulatory arrest and the histology was normal, and there was no correlation with the age of the donors. The islet content of insulin (ng/microgram dry islet) was 8.5 +/- 1.2 (mean +/- SEM). Isolated islets were loaded with 45Ca in the presence of 20 mM glucose and placed in a perfusion apparatus for further studies of the 45Ca washout. The decrease of washout of radioactivity in Ca2+-deficient medium offers support for the existence of a Ca2+-Ca2+ exchange process. When added in a concentration of 20 mM, glucose tended to stimulate 45Ca efflux in perfusion medium of ordinary ionic composition but inhibited this process when the medium was deficient in Ca2+. Exposure to the calcium ionophore X-537A resulted in immediate stimulation of of 45Ca efflux from human islets as previously observed for islets from rats and mice. This suggests that Ca2+ has a direct regulatory role for insulin release also in humans.

Adolescent↗
PubMed1977

Metabolic response to isologous transplantation of small numbers of isolated islets of Langerhans in the rat.

Pancreatic islets from adult donors were transplanted intraportally into 32 inbred, adult AGUS rats with streptozotocin diabetes. The islets were isolated with collagenase and counted individually. A relationship between the number of islets transplanted and the metabolic response could be demonstrated. Transplantation of less than 200 islets did not change the diabetic state. Rats receiving 200-220 improved, while recipients of 240-800 islets all exhibited normal values of blood glucose, plasma insulin, urine volume and urine glucose. The glucose tolerance, however, remained abnormal in all animals.

Animals↗
PubMed1977

Use of trypsin for isolation of islets of Langerhans in the rat.

A new technique for pancreatic islet isolation, based on trypsin administered into the pancreatic duct system and a reduced amount of collagenase for digestion of the removed and chopped pancreatic tissue, yielded viable islets as judged by the metabolic response of 27 inbred, streptozotocin-diabetic rats after intraportal transplantation of the islets: all recipients of greater than 240 islets normalized their blood glucose, plasma insulin, urine volume and urinary glucose. The number of islets isolated was the same as with the conventional collagenase technique.

Animals↗
PubMed1977

Viability of the islets of Langerhans after warm ischemia as judged by isologous transplantation.

The influence of warm ischemia on pancreatic islet viability was studied by means of 63 isologous transplantations in adult AGUS rats. The pancreases were harvested 0, 20 and 40 min after circulatory arrest. The islets were isolated with collagenase and transplanted intra-portally in known numbers into streptozotocin-diabetic recipients. The islet-dose-metabolic-response relationships in three groups of recipients were compared. No significant difference was found in the quantitative yield. The smallest number of islets which reversed diabetes increased by 25% after a period of warm ischemia regardless of its duration.

Animals↗
PubMed1976

The risk of renal allograft rejection following angiography.

In a retrospective study of 173 immediately functioning primary kidney transplants, correlation between agiography and renal allograft rejection was studied during the first 14 days. It was found that rejection was more frequent in kidneys undergoing angiography than in those not undergoing angiography. It was also found that in kidneys undergoing angiography an overwhelming number of the rejections started the day after angiography. These differences in rejection frequency could not be explained by differences in HLA matching or the origin of the kidneys. These findings suggest a possible connection indicating that the angiography might elicit an acute rejection episode. A possible mechanism for starting this reaction might be activation of the complement system which was found in 50% of the patients undergoing angiography in peripheral blood and in 100% when studied in vitro.

Angiography↗
PubMed1976

Metabolism in the hypothermically perfused kidney. Production and utilization of lactate and utilization of acetate in the dog kidney.

The mechanism for the high lactate production during hypothermic kidney perfusion has not been clarified previously. The metabolism of lactate and acetate was studied in 23 dog kidneys during continuous hypothermic perfusion. The perfusions were performed in a Gambro machine with a perfusate based on human serum albumin. With a perfusate containing fatty acid extracted albumin, which was almost free of fatty acids, the glucose uptake of the kidney was more pronounced than during perfusion with a fatty acid-rich perfusate. The high glucose uptake under this perfusion condition was associated with a lower lactate production and a higher glucose oxidation rate. In perfusions with a perfusate containing lactate at a concentration of 2.5 mmol/l a considerable lactate uptake of the kidney was shown. By isotope dilution technique the production and uptake rate of lactate was estimated at 4.4 and 8.0 mumol/g kidney and day in two experiments. The labeled lactate carbon was recovered in CO2, and glucose in the perfusate indicating a continuous oxidation and gluconeogenesis. Acetate was used by the kidney both for oxidation and for gluconeogenesis. Addition of acetate to the ordinary fatty acid-rich perfusate caused an enhanced lactate production from the perfused kidney. The results indicate that the high lactate production during hypothermic perfusion of kidneys is mainly dependent on a metabolic blockade at the level of pyruvate dehydrogenase.

Acetates↗
PubMed1976

Extracorporeal renal surgery for renovascular hypertension.

Nine cases of renovascular hypertension caused either by lesions in the distal part of the renal artery or by proximal renal atery stenosis where local reconstruction was considered dangerous were treated by extracorporeal reconstructive surgery and autotransplantation. The kidney were removed, cooled and preserved by simple hypothermia during workbench reconstruction on a separate side table. After reconstruction the kidneys were reimplanted to the groin. One kidney was lost due to infection and bleeding. All patients were preoperatively severely hypertensive. Blood pressure was normalized in all cases but one with a homotransplanted kidney which also was undergoing chronic rejection. The method is simple and safe and offers new possibilities to treat lesions in the kidney which previously were impossible or very risky to treat surgically. It is a safe alternative to conventional methods in case of anatomical structures making local reconstruction difficult.

Adult↗
PubMed1976

Kidney preservation by continuous hypothermic albumin perfusion without membrane oxygenation.

Continuous hypothermic albumin perfusion in the new Gambro device utilising surface oxygenation of the perfusate was studied in 20 consecutive human kidneys at the Transplantation Clinic in Gothenburg. The results were compared with previous results of kidney storage using simple hypothermia and continuous perfusion with membrane oxygenation. The mean preservation time was increased from eight and 24 hours in the previous material to 30 hours in the studied group. Immediate onset of function occurred more frequently after surface oxygenation and all kidneys perfused for the longest period of 30 to 48 hours, had immediate onset of function. No increased LDH release was observed after prolonged perfusion. Delayed onset of function could in most cases be attributed to prolonged warm ischaemia time in which cases also increased LDH release was observed. Continuous albumin perfusion using surface oxygenation was found to be equally efficient in clinical practice as the previously used system with membrane oxygenation.

Albumins↗
PubMed1976

Multiple arterial occlusions and hypertension probably caused by an oral contraceptive: a patient in whom the development of renovascular hypertension has been followed.

An 18-year-old woman taking an oral contraceptive was admitted to hospital because of a stroke due to occlusion of three branches of the right middle cerebral artery. She later developed renovascular hypertension due to occlusion of one of two renal arteries on the right side. Occlusion of the ceoliac artery was also found. The circumstances suggest that the occlusions were caused by multiple emboli, the source of which could not be identified. The kidney with the circulatory disturbance was shown to have a persistent abnormal renin secretion three and six months after the stroke, but the peripheral renin level was lower at the second investigation. Cardiac function studies revealed an alarming degree of left ventricular hypertrophy, and satisfactory blood pressure control could not be maintained despite increasing antihypertensive therapy. Surgical corrrction of the circulatory disturbance promptly led to normotension without drugs, and the patient has remained normotensive during the postoperative observation period of twelve months. The oral contraceptive was probably responsible for precipitating the vascular occlusions, but no predisposing factors or warning symptoms were present to identify this patient as being at risk.

Adolescent↗
PubMed1975

Glucagon and insulin release from the allografted canine pancreas.

Six previously pancreatectomized dogs were transplanted with duct-ligated, pancreatic allografts. Glucagon and insulin levels in the venous outflow from the graft and in the systemic circulation were determined during the first 60 minutes after transplantation. Two of the dogs were subjected to L-arginine stimulation 5 days after transplantation and the glucagon levels in the venous outflow from the graft were determined. The glucagon and insulin concentrations increased rapidly after transplantation, describing a biphasic curve. In response to L-arginine stimulation, an increased glucagon release was observed.

Animals↗
PubMed1975

Function of the duct-ligated canine pancreatic allograft.

Heterotopic transplantation of a duct-ligated canine pancreas was performed in 20 previously pancreatectomized, non-related recipient dogs. A technical procedure was elaborated for this grafting. It was found that early, fatal postoperative bleeding in the recipient could be avoided when the interval between pancreatectomy and transplantation was reduced from 7 to 2-4 days. The early endocrine function was studied in 15 surviving animals by determination of blood glucose and serum insulin during fasting and during glucose load. 24 h after transplantation the blood glucose values were normal and 4-8 days after transplantation the glucose tolerance was within normal limits. The serum insulin was on a supranormal level, also during glucose load. The early endocrine capacity of the transplanted duct-ligated pancreas after transplantation was found to be satisfactory, restoring the blood glucose in the pancreatectomized recipients to normal levels.

Animals↗
PubMed1975

Behaviour of the duct-ligated canine pancreas during hypothermic albumin perfusion.

The behaviour of eight duct-ligated canine pancreata was studied during 23 hours of continuous, hypothermic perfusion, with an albumin electrolyte solution. The organs developed a considerable oedema during perfusion. This did not seem to influence on the vascular resistance of the organs. A continuous insulin release, a moderate increase in LDH concentration and only small changes in the electrolyte concentrations were observed in the perfusate, indicating only a moderate degree of cellular damage.

Albumins↗