Russell Kerschmann

Tumor Angiogenesis Correlates with Lymph Node Metastases in Invasive Bladder Cancer

Neovascularization of tumor tissue (tumor angiogenesis) is considered essential for tumor growth, proliferation and eventually metastasis. Microvessel density or count, a measure of tumor angiogenesis, correlates with clinical outcome in skin, breast, lung and prostate carcinomas. To determine whether an association of tumor angiogenesis and nodal metastasis exists in invasive bladder cancer, microvessel counts in 41 primary invasive stages (T2 to 4,NX,M0) bladder cancers were assessed. Microvessels were identified by immunostaining of endothelial cells for factor VIII-related antigen. Microvessels were scored in selected areas showing active neovascularization, either counting a 200 x field (0.74 mm.2) or by using a 10 x 10 square ocular grid (0.16 mm.2). The microvessel count correlated with the presence of occult lymph node metastases (p < 0.0001) by both techniques. The mean microvessel count in 27 patients without lymph node metastases was 56.2 microvessels per 200 x field (standard deviation [SD] 29.5, range 7 to 130) or 28.6 microvessels per grid (SD 14.4, range 4 to 65). The 14 patients with histologically proved lymph node metastases showed mean 138.1 microvessels per 200 x fields (SD 37.9, range 82 to 202) or 74.7 microvessels per grid (SD 14.4, range 43 to 115). Good correlation was noted between area and grid counting (r = 0.97). Tumor T stage, grade and the presence of vascular or lymphatic invasion did not correlate with the presence of lymph node metastases (p = 0.41, 0.59 and 0.26, respectively). Microvessel count may provide important information regarding the risk of occult metastasis in patients with invasive bladder carcinomas.

Comparison of five histopathologic methods to assess cellular proliferation in transitional cell carcinoma of the urinary bladder

Transitional cell carcinomas of the urinary bladder vary in their biologic potential, which may be correlated with the grade and stage of the tumor. Cellular proliferation may prove to be another measure of predicting tumor biologic potential. We have compared five different methods to assess proliferation in 26 tumors and correlated these results with tumor grade and stage. A portion of each tumor was incubated in vitro with bromodeoxyuridine (BrdUrd). For each tumor this was compared with at least three of the following four other markers of proliferation: mitotic count, silver-stained nucleolar organizer regions, immunohistochemical staining with Ki67, and proliferating cell nuclear antigen. Statistical correlations were seen between tumor grade and stage and these markers. There were strong correlations between the BrdUrd labeling index (LI) and both the Ki67 LI and proliferating cell nuclear antigen LI. The correlation between the BrdUrd LI and mitotic count was more tenuous; no significant correlation was found between BrdUrd LI and silver-stained nucleolar organizer region count. The correlation between these measurements of proliferation and tumor grade and stage was less strong. Our data suggest that cellular proliferation of transitional cell carcinomas can be reliably assessed with several different markers and that most of these markers can be correlated with tumor grade but not with stage.

Frequent homozygous deletion of cyclin-dependent kinase inhibitor 2 (MTS1, p16) in superficial bladder cancer detected by fluorescence in situ hybridization.

Deletion of all or part of chromosome 9 is a well‐described genetic alteration in bladder tumors. It has been proposed that inactivation of a tumor‐suppressor gene on chromosome 9, is an important event in tumor development. Recent reports have supported cyclin‐dependent kinase inhibitor 2 (CDKN2, also known as MTS1, INK4, p16) at 9p21 as a candidate tumor‐suppressor gene in solid tumors. However, the prevalence of CDKN2 mutations in primary bladder tumors has been controversial. Therefore, we applied gene‐specific probes for CDKN2 and the interferon alpha gene (IFNA), also located at 9p21, to characterize further the genomic deletions at this locus in bladder cancer. Seventeen superficial (pTa or pTI) bladder tumor specimens were examined for gene deletion by fluorescence in situ hybridization. Dual‐labeling hybridization with a repetitive pericentromeric probe for chromosome 9 and a gene‐specific probe for CDKN2 was performed to characterize the gene copy number in relation to the chromosome 9 copy number on a cell‐by‐cell basis. Homozygous deletion for CDKN2 without homozygous IFNA deletion was found in 5 of 17 tumors tested. Both genes were deleted in one additional case, and one tumor showed deletion of IFNA without deletion of CDKN2. Homozygous deletion at the 9p21 locus was found only in tumors having monosomy for the chromosome 9 centromeric signal. These results indicate that the homozygous deletion of the CDKN2 gene is a frequent and early event in superficial bladder cancer. Genes Chromosom. Cancer 19:84–89, 1997.

High Resolution Radiography of Cadaveric Kidneys: Unraveling the Mystery of Randall's Plaque Formation

PURPOSE We used high resolution radiography to identify and characterize Randalls plaques in cadaveric kidneys. MATERIALS AND METHODS A total of 50 consecutive sets of cadaveric kidneys was fixed, bivalved and imaged with micro-focal spot magnification radiography. Papillary calcifications were identified, localized and processed for light microscopy. Special immunohistochemical stains were implemented to aid localization of ectopic calcifications. Patient medical records and autopsy results were retrospectively evaluated and correlated with radiographic papillary calcifications. RESULTS Of the 92 renal units with complete data 52 (57%) had radiographic evidence of renal medullary calcifications consistent with Randalls plaques. Unlike the original description of this condition, calcifications extended deep into the papilla. A history of hypertension was the only clinical parameter correlating with papillary calcifications. Calcium deposition was localized to the basement membrane of collecting tubules and vasa recta, and papillary interstitium. CONCLUSIONS Randalls plaques are not merely subepithelial deposits. Rather, they appear to extend deep within the papilla, and are intimately associated with collecting tubules and vasa recta. An association between papillary calcifications and urinary stone formation has yet to be proved but is under investigation.

Metabolism of compound A by renal cysteine-S-conjugate β-lyase is not the mechanism of compound A-induced renal injury in the rat

Compound A [CF2 double bond C(CF3)OCH2 F], a vinyl ether produced by CO2 absorbents acting on sevoflurane, can produce corticomedullary junction necrosis (injury to the outer stripe of the outer medullary layer, i.e., corticomedullary junction) in rats. Several halogenated alkenes produce a histologically similar corticomedullary necrosis by converting glutathione conjugates of these alkenes to halothionoacetyl halides. To test whether this mechanism explained the nephrotoxicity of Compound A, we blocked three metabolic steps which would lead to formation of a halothionoacetyl halide: 1) we depleted glutathione by administering dl-buthionine-S,R-sulfoximine (BSO); 2) we blocked cysteine S-conjugate formation by administering acivicin (AT-125); and 3) we inhibited subsequent metabolism by renal cysteine conjugate beta-lyase to the nephrotoxic halothionoacetyl halides by administering aminooxyacetic acid (AOAA). These treatments were given alone or in combination to separate groups of 10 or 20 Wistar rats before their exposure to Compound A. We hypothesized that blocking these metabolic steps should decrease the injury produced by breathing 150 ppm of Compound A for 3 h. However, we found either no change or an increase in renal injury, suggesting that this pathway mediates detoxification rather than toxicity. Our findings suggest that the cysteine-S-conjugate-mediated pathway is not the mechanism of Compound A nephrotoxicity and, therefore, observed interspecies differences in the activity of this activating pathway may not be relevant in the prediction of the nephrotoxic potential of Compound A in clinical practice. (Anesth Analg 1996;82:770-4)

Acetaminophen predisposes to renal and hepatic injury from compound A in the fasting rat.

Results of previous studies of Compound A, a degradation product of sevoflurane, suggested that decreases in glutathione stores may increase potential Compound A nephrotoxicity.By depleting these stores, fasting and various drugs may augment such nephrotoxicity. To test this possibility, we pretreated fasted Fisher rats with intraperitoneal 0 (vehicle only), 250, 500, or 1000 mg/kg of acetaminophen, a commonly used drug that depletes glutathione stores. After pretreatment, we administered Compound A for 3 h at concentrations ranging from 0 to 200 ppm. The larger doses of acetaminophen predisposed to greater renal and hepatic injury. For example, at 100 ppm Compound A, no rats had renal cortical injury when given vehicle only or 250 mg/kg acetaminophen, but 90% (9 of 10 rats) had injury at 500 mg/kg and 100% (13 of 13) at 1000 mg/kg. Similarly, at 100 ppm Compound A, hepatic injury was not evident with vehicle only or 250 mg/kg, but occurred in 30% of rats at 500 mg/kg, and in 69% at 1000 mg/kg. Given the considerable differences between humans and rats, and given the large doses of acetaminophen required, the clinical relevance of these findings is unclear. If clinically relevant, circumstances producing glutathione depletion (e.g., ingestion of drugs such as acetaminophen, or nutritional deficiencies) may predispose to renal or hepatic injury from Compound A in patients given sevoflurane at low fresh gas flow rates. (Anesth Analg 1997;84:169-72)