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Biomedical subjects

M R Buhl

Publications and source records attributed to M R Buhl.

36 records · Page 2Linked to original sources
PubMed1980

The effect of cooling rate during perfusion on function and morphology of rabbit kidney grafts.

The effect of cooling of rabbit kidneys during the initial flush with Collins' solution for simple hypothermic storage was studied. After cooling at an average rate of 3.7 degrees C/min. graft function was found to be immediately life-sustaining, and renal morphology after perfusion as well as 30 min. and 24 hours posttransplant was found to be normal. Posttransplant function after cooling at a rate of 7.2 degrees C/min. was significantly lower, permitting survival of only 30% of recipient animals, and damage was seen in proximal tubular cells.

Animals↗
PubMed1979

Urid acid accumulated in isolated kidney grafts: an assessment of agonal ischaemia.

Hypoxanthine-xanthine washed out from kidney tissue during preservation has previously been found to be a reliable measure of the in vitro assessment of the deleterious effect of ischaemia on the functional regenerative ability of the graft. We have now studied the question: can uric acid accumulation in the isolated kidney graft be employed as a retrospective measure of the agonal ischaemia? We have found that uric acid alone accumulates in renal tissue during the agonal phase, in an amount that remains unchanged during the subsequent in vitro ischaemia. The determination of hypoxanthine-xanthine and uric acid in kidney perfusate samples during preservation must thus be presumed to be an optimal clinical-chemical method of assessing the graft ischaemia.

Adenosine Diphosphate↗
PubMed1979

The predictive value of 5'-adenine nucleotide depletion and replenishment in ischaemic rabbit kidney tissue.

Renal ischaemia produced by clamping of the blood vessels in situ for periods of 10 to 150 minutes resulted in a progressive depletion of the total content of adenylates in the kidney tissue (sigma ATP, ADP, AMP). Initial dephosphorylation of ATP and ADP, resulting in further catabolism of AMP to hypoxanthine and xanthine, accumulated in the ischaemic tissue. The postischaemic ability of the kidney tissue to functional regeneration was in correlation with the ischaemic adenylate loss (r = +0.94, P less than 0.001) as well as the accumulation of hypoxanthine and xanthine (r = -0.90, P less than 0.001). The initial adenylate resynthesis rate was constant during recovery (0.5--0.8 mumol/g . h-1), independent of the duration of the preceding ischaemia. Determination of the postischaemic adenylate regeneration thus gave no additional prediction of the reversibility of the ischaemic parenchymal damages.

Adenosine Diphosphate↗
PubMed1976

Hypoxanthine excretion during preservation of rabbit kidneys for transplantation. An assessment of the ischaemic damage.

The loss of 5'-adenine nucleotides from kidney tissue subjected to acute ischaemia can be indirectly estimated by washing out the end product of catabolism, hypoxanthine, from the ischaemic tissue to the perfusate. As a correlation has previously been demonstrated between the duration of the previous normothermic ischaemia and the washout of hypoxanthine during preservation, hypoxanthine has been studied as a prospective measurement of ischaemic renal damage, by transplantation of rabbit kidneys. The results were compared to the already established parameters L-lactate and lactate dehydrogenase. Different ischaemic traumata and methods of preservation have been employed in order to determine the relationship of these parameters to the ischaemic kidney damage as evaluated by the functional regeneration of the grafts after autotransplantation. The wash-out of hypoxanthine was found to be correlated to such a degree to the reversibility of the ischaemic cell degeneration that a certain in vitro exclusion of the irreversibly damaged kidney grafts was possible. It is concluded that hypoxanthine can function as a reliable and sensitive measurement for the in vitro establishment of the ischaemic kidney parenchymal damage, and that it can be employed clinically with advantage.

Animals↗
PubMed1976

The postanoxic regeneration of 5'-adenosine nucleotides in rabbit kidney tissue during in vitro perfusion.

The adenylate metabolism in rabbit kidney tissue was investigated, by isolated normothermic bloodless perfusion, during anoxic cell deterioration and postanoxic recovery in vitro. The amounts of hypoxanthine washed out during continuous anaerobic perfusion were shown to represent a definite loss of intracellular purine. No salvage of the endogenic liberated oxypurine was found to occur during postanoxic reoxygenation. The ability to restore the content of 5'-adenosine nucleotides failed after 60-120 min of anaerobic perfusion. Adenosine, adenine, inosine, hypoxanthine, and D-ribose added to the perfusate during reoxygenation were investigated with regard to their ability to stimulate postanoxic adenylate regeneration. Adenosine alone added in a concentration of more than 1 mmol/l showed a significant stimulation of the adenylate synthesis, with complete regeneration of the adenylate content after 180 min of preceding anoxia. In can be concluded that anoxia kidney deterioration is associated with a progressive loss of intracellular oxypurine, and a decreasing ability to regenerate adenylates after reoxygenation, which could be prevented by exogenic addition of adenosine. It appears reasonable to assume that the results obtained reflect the adenylate metabolism of a kidney graft during the postischaemic phase immediately after implantation.

Adenine↗
PubMed1976

Oxypurine excretion during kidney preservation: an indicator of ischaemic damage.

The loss of 5'-adenine nucleotides in ischaemic kidney tissue is related to the postischaemic survival of the organ. It has previously been demonstrated that the catabolism of 5'-adenine nucleotides in ischaemic tissue can be evaluated indirectly by the washout of the final products: hypoxanthine, xanthine, and inosine. The present study indicates a relationship between postischaemic renal function and the duration of normothermic ischaemia. It further demonstrates a linear correlation between the duration of normothermic ischaemia and the quantity of hypoxanthine/xanthine recovered from the perfusate. Thus the method may be used for the evaluation of possible renal grafts.

Adenine Nucleotides↗
PubMed1975

Breakdown of 5'-adenine nucleotides in ischaemic renal cortex estimated by oxypurine excretion during perfusion.

The catabolism of 5'-adenine nucleotides in the cortex of the rabbit kidney was studied during normothermic and hypothermic ischaemia. Changes were found in the cortical content of ATP, ADP, AMP, and SAN (the sum of 5'-adenine nucleotides) during ischaemia; those changes were delayed by hypothermia. The loss of SAN was found to be significantly correlated to the duration of normothermic as well as hypothermic ischaemia. The oxypurines hypoxanthine and xanthine and the nucleoside inosine were shown to be the final products of the catabolism of 5'-adenine nucleotides. An accumulation of hypoxanthine-xanthine and inosine in the tissue and a corresponding excretion in the perfusion fluid occurred simultaneously with the catabolism of 5'-adenine nucleotides, in equivalent amounts. It is concluded that determination of the amount of oxypurines excreted during kidney preservation is an indirect measure of the loss of SAN in the tissue, and a reflection of the changes in the metabolic state.

Adenine Nucleotides↗
PubMed1975

Preservation of kidneys for transplantation. Assessment of ischemic damage by renal autoperfusion.

Autoperfusion of canine kidneys was investigated as an alternative method to determinate the ischmic organ damage following various preservation procedures. As a compromise between implantation of the donor kidney and normotherimic isolated perfusion, autoperfusion is shown to offer some advantages in the study of the pathophysiology of the ischemic damaged kidney. Within 3 hours of autoperfusion, we obtained detailed information about the immediate regenerative ability of the glomerular, tubular, and vascular functions following various sorts of ischemic trauma.

Animals↗
PubMedDate not supplied

Prevalence of antibodies to hepatitis C virus among Omani patients with renal disease.

The prevalence of hepatitis C virus (HCV) infection in Omani patients with renal disease was determined using a second-generation enzyme immunoassay which detects antibodies to three HCV antigens. Based on the results of this assay, 27 of 102 (26.5%) sera from patients on haemodialysis, 11 of 82 (13.4%) sera from kidney transplant patients, and 1 of 103 (1%) sera from non-dialysed, non-transplanted patients with various renal diseases had antibodies to HCV. Among healthy subjects, none of 134 medical students and 5 of 564 (0.9%) blood donors were anti-HCV positive. Thus, the prevalence of HCV infection in dialysis and renal transplant patients was significantly higher than that found in patients with renal disease who had been neither dialysed nor transplanted (p < 0.05). In the latter group of patients, the frequency of anti-HCV was low, and comparable to that of healthy Omani subjects.

Adolescent↗
PubMedDate not supplied

Temporofacial zygomycosis in a pregnant woman.

A 38-year-old Omani woman, seven months pregnant, developed extensive zygomycosis involving maxillary and temporal bones. No evidence of any underlying immune deficiency was detected except that which may be attributed to pregnancy. After delivery the patient was treated with repeated courses of amphotericin B, which resulted in a complete clinical resolution. Zygomycosis in uncomplicated pregnancy has not been previously described.

Adult↗
PubMedDate not supplied

Use of medical chemoprophylaxis and antimosquito precautions in Danish malaria patients and their traveling companions.

BACKGROUND: The number of malaria cases imported to Denmark has been increasing for some years. To analyze the background for this we assessed the use of protective measures in Danish travelers visiting malarious areas. METHOD: Post-travel questionnaires were given during hospitalization to malaria patients, and sent by mail to their traveling companions. RESULTS: In total, 142 persons participated. Only 32% of the travelers used chemoprophylaxis correctly, according to Danish recommendations. Twelve percent of the travelers did not use chemoprophylaxis. Average compliance was 52%. Insufficient drug dosage was reported by 13%, and use of nonrecommended drugs by 7% of the travelers. Thirty-seven percent used insufficient antimosquito precautions, a problem which often coincided with irregular use of chemoprophylaxis. Malaria patients, sole travelers, and travelers with other ethnical background than Danish, were subgroups using insufficient malaria prophylaxis more frequently than healthy traveling companions. CONCLUSION: Insufficient use of the available antimalaria precautions by Danish travelers contributes greatly to maintaining a high incidence of imported malaria. Increased attention from physicians in educating travelers is important for optimizing malaria prophylaxis.

Adult↗