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Biomedical subjects

G Kootstra

Publications and source records attributed to G Kootstra.

At least 145 records · Page 8Linked to original sources
PubMed1988

Nucleotides, nucleosides, and oxypurines in human kidneys measured by use of reversed-phase high-performance liquid chromatography.

An HPLC technique is presented for determining adenine nucleotides and related substances in renal cortical tissue. Nineteen metabolic substances can be resolved in a single 25-min run, with use of a gradient-elution system. The mean intra-assay CV is 2.4%, the interassay CV 5%. The lower detection limit for substances commonly present in kidney tissue--such as ATP, ADP, AMP, GTP, GDP, GMP, IMP, inosine, adenosine, hypoxanthine, and xanthine--ranges from 0.6 to 3.6 mumol/L, corresponding to 18 and 107 pmol applied to the column. For reliable analysis, a specimen of renal cortex weighing at least 5 mg (wet weight), taken during donor nephrectomy, during cold storage of the kidney, and 1 h after the onset of reperfusion, can be used. The method presented provides a rapid, reproducible diagnostic tool for assessing the chemical energy status of human kidneys in renal surgery and transplantation.

Adenine Nucleotides↗
PubMed1987

Immunohistological observations in rat kidney allografts after local steroid administration.

In this report we investigated local regulatory mechanisms in graft rejection and their response to local immunosuppressive therapy. For this purpose local immunosuppression was induced in rat kidney allografts by intrarenal infusion of prednisolone. Intrarenal drug delivery resulted in high drug levels within the graft and low systemic drug levels. Systemic drug levels were by themselves not sufficiently immunosuppressive to induce graft survival, and local prednisolone levels within the graft proved to be responsible for prolongation of graft survival. During intrarenal drug delivery, systemic responsiveness to the renal allograft proved normal, since intrarenally treated grafts were infiltrated by MHC class II-positive host cells and, except for a somewhat lower percentage of macrophages, cellular infiltration in intrarenal treated grafts was comparable to untreated grafts. However, T cells and macrophages present in intrarenally treated grafts were not able to destroy the grafted tissue. Local immunosuppressive therapy resulted in inhibition of IL-2-R expression, absence of IFN-gamma, and prevention of MHC class II induction on grafted tissue. These observations strongly indicate the presence of local regulatory mechanisms in graft rejection. The experimental model described can be used for further analysis of these intragraft events. Moreover, the results demonstrate that local immunosuppressive therapy can contribute to effective inhibition of cellular immune response in graft rejection.

Animals↗
PubMed1987

In vivo dynamic 99mTc-HIDA scintigraphy after hepatocyte transplantation: a new method for the monitoring of graft function.

In vivo dynamic 99mTc-HIDA scintigraphy was tested as a method for graft function monitoring after hepatocyte transplantation (HTX). Bilirubin uridyldiphosphate glucuronyl transferase-deficient rats received 10(7) viable isolated hepatocytes from congenic nondeficient donors by intrasplenic injection. The transplanted rats were divided into 2 groups. Three months after HTX, one group underwent 99mTc-HIDA scintigraphy, the other was subjected to bile analysis for the detection of bilirubin glucuronides (the presence of which would indicate biochemical activity of transplanted hepatocytes). Histological examination of the spleen of all animals was performed at the end of the experiment. The same experimental protocol was applied to 10 sham-treated enzyme-deficient rats serving as controls. The scintigraphic studies showed that spleens of transplanted rats did accumulate 99mTc-HIDA, this in contrast to sham-treated rats. Furthermore, time-activity curves of liver and spleen of HTX-treated rats showed similar kinetic patterns, suggesting a biologically normal function of the hepatocytes grafted in the spleen. Bilirubin glucuronides were excreted by transplanted rats, not by control rats. Histological examination of the spleen revealed hepatocyte survival in all HTX-treated rats. These findings demonstrated a correlation between increased splenic uptake of 99mTc-HIDA and biochemical activity and morphological survival of intrasplenic donor hepatocytes. In conclusion, in vivo dynamic 99mTc-HIDA scintigraphy appears to be an ideal method for noninvasive graft function monitoring after intrasplenic HTX.

Animals↗
PubMed1987

Appearance of enzymes in plasma or urine following renal injury.

The present study evaluates the relevance of plasma enzyme activity in the quantitative assessment of renal injury. In a canine model, enzyme release from kidneys to plasma and urine was studied following an artificial parenchymal enzyme infusion in healthy and ischaemic kidneys. The cumulative enzyme activity in plasma and urine was calculated. Within 1 h of the start of the infusion, 80% of the infused enzyme was recovered in plasma, whereas urinary accumulation was negligible. A similar enzyme distribution between these compartments was obtained if the kidneys were ischaemically damaged before the start of the infusion. Thus enzymes released into the renal cortical interstitium are very rapidly transported to the vascular system and are quantitatively recovered in plasma. Experimental renal infarction revealed that cell death due to ischaemia also resulted in enzyme accumulation in plasma.

Alanine Transaminase↗