V Paradis

In situ detection of lipid peroxidation by-products as markers of renal ischemia injuries in rat kidneys.

PURPOSEnLipid peroxidation is an autocatalytic mechanism leading to oxidative destruction of cellular membranes. In renal transplantation, this mechanism is triggered by ischemia/reperfusion and may be of relevance in graft failure.nnnMATERIALS AND METHODSnUsing specific antibodies directed against malondialdehyde (MDA) and 4-hydroxynonenal (HNE) adducts, major aldehydic metabolites of lipid peroxidation, we investigated, in situ, by means of an immunohistochemical procedure, the occurrence of lipid peroxidation during different warm ischemic periods of 0, 15, 30, 45 and 60 minutes in rat kidneys prior to reperfusion. The same experiments included followup of the rats after nephrectomy and reperfusion for 10 days.nnnRESULTSnWe observed superficial and deep cortex immunostaining with both antibodies against MDA and HNE after 30 minutes of warm ischemia. This immunostaining was observed in the absence of any histological lesions, as assessed by routine staining. After 45 and 60 minutes of warm ischemia, lipid peroxidation byproducts were detected both in the cortex and in the medulla, which is associated with 33% and 66% of rat deaths respectively.nnnCONCLUSIONSnThis study confirms the involvement of the lipid peroxidation process in kidney damage during anoxia before reperfusion, and its extension to the whole organ. Lipid peroxidation byproducts were detectable in warm ischemic kidney, and the presence of medulla immunostaining was associated with the animals death. Lipid peroxidation immunostaining might thus be useful as a sensitive tool to detect ischemic damage after warm ischemia prior to reperfusion, as well as in the decision to carry out kidney transplantation in humans.

Molecular expression of PSMA mRNA and protein in primary renal tumors.

Human prostate‐specific membrane antigen (PSMA), a 100‐kDa integral transmembrane glycoprotein, is considered to be a highly specific marker of the prostate gland, and has successfully been used as a marker of circulating prostatic epithelial cells. Extended PSMA homology has been demonstrated with a cDNA found in rat cerebral and renal tissues. In this study, we aimed to evaluate the expression of PSMA mRNA in a variety of human renal cancer tissues (n = 20) and cell lines (n = 12). Using reverse transcriptase‐polymerase chain reaction, DNA sequencing, blottings, and specific anti‐PSMA labelling with CYT 351 antibody, we identified PSMA mRNA and protein in normal and in neoplastic renal tissue. The sequence of the polymerase‐chain‐reaction products is identical to that of PSMA cDNA derived from prostate tissue. Immunological staining with the CYT 351 reveals that PSMA is expressed mainly in tubular cells. Since PSMA does not appear to be restricted to prostatic tissue, this novel biomarker may prove useful in the staging of renal cancer and in the search for the hematogenous spread of renal cells. Int. J. Cancer 80:799–803, 1999.

In situ detection of telomerase enzymatic activity in human hepatocellular carcinogenesis.

Telomerase enzymatic activity has been detected in most human malignant tumours including hepatocellular carcinoma. In order to assess the cellular source, the topographic distribution, and the chronology of telomerase re‐expression during human liver carcinogenesis, an in situ technique derived from the standard TRAP (telomeric repeat amplification protocol) assay was set up that allowed the detection of telomerase enzyme activity at the cellular level on frozen liver tissue sections. In situ TRAP (ISTRAP) was performed on 27 hepatocellular carcinomas (HCCs) and 57 non‐tumour livers, including normal liver without HCC, liver samples adjacent to tumour with and without hepatic cirrhosis, and biopsies of chronic hepatitis. In HCC, telomerase was detected in the nuclei of liver tumour cells in 23/27 cases (85%), with a heterogeneous distribution within the tumour. This signal was also detected in clusters of hepatocytes in 16/26 (61%) samples of liver adjacent to HCC, in 10/23 (43%) cases of chronic viral hepatitis without adjacent HCC, and in scattered nuclei of 2/8 histologically normal livers. Comparison of the results obtained with ISTRAP and standard TRAP assays on tissue extracts suggests a gain in sensitivity with the in situ technique. This study confirms that telomerase is expressed in most HCCs and suggests that focal telomerase reactivation is an early event during human liver carcinogenesis. ISTRAP is a sensitive technique that allows the study of telomerase expression in the morphological context. Copyright

Successful treatment of encrusted pyelitis in a renal transplant with local acidification and surgical ileocaliceal anastomosis.

Encrusted pyelitis was initially described in 1993. The incidence has increased with the increasing number of patients with immunodeficiency, particularly those with a renal transplant. This condition is secondary to urinary tract infection due to ureolytic microorganisms. More than 45 microorganisms have been implicated as etiological factors of encrusted cystitis and pyelitis. The treatment of encrusted cystitis or pyelitis includes specific antibiotics, urinary acidification and endoscopic excision of the calcified lesions. When treatment is not rapidly instituted, excision of the transplant is necessary. Nevertheless, in some cases the renal transplant may be surgically and medically treated. Such therapy may be beneficial to the renal transplant, which may be functional after infection. We report a case of renal transplant salvage after the development of encrusted pyelitis.

Expression of aldehydic lipid peroxidation products in rat kidneys during warm ischemia

Abstract DURING warm ischemia (WI), liberation of metabolites such as superoxide anions and hydroxyl radicals induce severe tissue damage. 1 Stress resulting from oxygen-derived free radical is highly involved in WI damage to kidney. The main targets of these molecules are membrane lipids. 2 The two prominent lipid degradation products are malondialdehyde (MDA) and 4-hydroxynonenal (HNE). They can be detected with biochemical assays or immuno-staining using antibodies against protein-linked MDA and HNE. This article describes the study to determine qualitatively and quantitatively the liberation of MDA and HNE. These molecules measured in kidney biopsies reflect kidney damage and could be considered as significant markers especially after WI.