Some observations on genetic factors in urolithiasis

Distribution of Langerhans cells and HLA class II molecules in prostatic carcinomas of different histopathological grade

We have investigated Langerhans cell (LC) distribution in 38 prostatic carcinomas, of various degrees of differentiation, by immunohistochemistry with a polyclonal anti-S-100 serum, furthermore evaluating the expression of HLA class II-DR by neoplastic cells using a monoclonal antibody (MoAb) that reacts with a monomorphic determinant in formalin-fixed paraffin-embedded tissue. Antiserum to S-100 protein identified LCs mostly in carcinomas ranging from grade 1 to grade 2, while LCs were inconspicuous in grade 4 and virtually absent in grade 5 cancers. Moreover, sections stained with the anti -HLA-DR MoAb displayed an immunoreactivity, both cytoplasmic and apical, especially confined to neoplastic glands of low grade (1-2) carcinomas. Although we did not find a direct correlation between the two parameters under investigation and lymphoid infiltrate, we were able to document an increased number of HLA class II-positive interstitial cells in low-grade carcinomas, corresponding mostly to macrophages. Our results indicate that LC number is inversely correlated to the histopathological grade and directly to the expression of HLA class II-DR molecules by tumor cells; we believe that this might be important in understanding the more favorable biological behavior of low-grade prostate carcinomas as opposed to the higher grades, since LCs and HLA class II molecules may provide a means of eliciting the immune response, both LCs and epithelial cells expressing HLA class II molecules being capable of direct antigen presentation to immune cells. In this context macrophages might play a primary role in controlling tumor progression. To the best of our knowledge this is the first time that an attempt is made to correlate LCs and HLA class II expression to histopathological grading of prostatic carcinomas. We would also suggest that the presence of LCs and HLA class II molecules, either singly or in combination, in carcinoma of the prostate represents a good prognostic indicator, being constantly associated with the clinically less aggressive low-grade tumors. The evaluation of these two parameters might prove useful in the assessment of intermediate grades where no valid histologic criteria have been found to predict the clinical course of the disease.

Heterozygous cystinuria and urinary lithiasis

Cystinuria is a recessively inherited transport disorder, with at least three mutant alleles (I, II, and III) demonstrable. I/I, II/II, and III/III homozygotes and I/II, I/III, and II/III compound heterozygotes (cystinuric patients) have high urinary concentrations of cystine, lysine, arginine, and ornithine and frequently form cystine stones. +/I heterozygotes (nondetectable) are phenotypically normal, whereas +/II and +/III heterozygotes (detectable) show variable increases in urinary cystine and lysine concentration and at times increases in urinary arginine levels. The objectives of the present study were to determine the frequency of +/II heterozygotes among stone-forming and nonstone-forming individuals from the same region of Brazil and to evaluate the possible relationship between heterozygous cystinuria and urinary lithiasis. When urine samples from 5,150 individuals (5,000 nonstone-forming individuals and 150 stone-forming individuals) were screened by the qualitative cyanide-nitroprusside cystine test, by thin-layer amino acid chromatography, and by quantitative amino acid determination by ion-exchange chromatography, 32 +/II or +/III heterozygotes (26 nonstone-forming and six stone-forming individuals) were detected. The frequency of detectable heterozygotes among the stone-forming individuals (1:25) was significantly higher than that among nonstone-forming individuals (1:104), which provides additional evidence that heterozygosity for +/II and +/III cystinuria is a risk factor in the formation of urinary stones. No significant difference was detected in urinary cystine concentration or in terms of the various characteristics of urolithiasis when stone-forming heterozygotes were compared to nonstone-forming heterozygotes. These data suggest that the tendency towards stone-forming among heterozygotes is probably owing to a complex and multifactorial mechanism.

Pathogenesis of renal calculi

Urolithiasis involving the upper urinary tract is a multifactorial disease that remains a significant health problem. A variety of intrinsic and extrinsic factors influence the incidence of disease in individuals and in all populations. At the level of the kidney, natural physicochemical processes result in crystalluria and the formation and growth of stones. Urinary supersaturation of some degree must be present but its significance may be altered by changes in urinary volume, pH, epitaxial relationships, and the presence or absence of naturally occurring inhibitors. A variety of environmental parameters acting through effects on the local urinary conditions determine which patients among a group of people inherently at risk will form stones. The above factors are considered herein with regard to the four major types of stone disease encountered today.

Thiol-disulfide interchange between cystine and N-2-mercaptoethyl-1, 3-diaminopropane as a potential treatment for cystinuria

The radioprotective compound WR2721 is a thiophosphate, which, when administered orally, is activated at the acid pH of the stomach to its free thiol (MDP). The free thiol is a mucolytic compound which acts via the reduction of disulfide bonds of mucin molecules. An equimolar mixture of MDP and cysteine, in urine at pH 6.0 and 37 degrees C, when oxidized by molecular oxygen, preferentially forms the soluble mixed disulfide between MDP and cysteine. The disulfide cystine will undergo thiol-disulfide interchange with MDP; as a result, cystine crystals are effectively dissolved. Moreover, in the presence of catalytic amounts of free thiol, the disulfide of MDP will undergo thiol-disulfide interchange with cystine to dissolve cystine crystals. The mixed disulfide of MDP with cysteine is soluble in urine at pH 6.0 and 37 degrees C to at least 100 mg/ml. Chromatographic procedures which permit the analysis of MDP and its mixed disulfide derivatives as MDP-sulfonic acid are described. By these procedures, it was demonstrated that 20% of a single oral dose of WR2721 was excreted as MDP derivatives in the urine of normal volunteers. These procedures will permit the evaluation of WR2721 in the treatment of cystinuria.

Histologic grading and the practicing urologist

Over the past 60 years, pathologists have identified three histologic features, tumor volume, glandular differentiation, and nuclear anaplasia, as important prognosticators of the malignant potential of prostatic adenocarcinoma. Several histologic grading systems have emerged to assess these morphological and cytological features, but problems with objectivity and reproducibility have been encountered. The failure of grading systems to predict accurately the malignant potential of individual tumors and the paucity of therapeutic options available have prevented many urologists from adopting these systems. Recent progress among stage A lesions has highlighted the clinical relevance of histologic grading systems, but advances are needed in prognostic techniques and therapeutic modalities before the practicing urologist can apply histologic information clinically among the majority of his patients.

Some questions raised by histologic study of RTOG protocols 75-06 and 77-06 as illustrated by selected samples

Histologic study of about 700 biopsy specimens from patients with prostate cancers collected by the Radiation Therapy Oncology Group (RTOG) reemphasized the difficulty in accurately predicting biologic behavior of the carcinoma in individual cases. Some well-differentiated carcinomas metastasized to regional lymph nodes. Histologic proof of lymph node metastases may be difficult to detect. Some duct carcinomas do not readily fit a Gleason pattern. A variety of histologic grades may be seen either in a single sample or after the passage of time in the same case. Some prostatic epithelial proliferations may closely simulate carcinomas by routine light microscopy, but are biologically benign. Some of these prostate lesions have histologic similarities to breast lesions.

Cancer of the prostate and aging: an autopsy study in black men from Washington, DC, and selected African cities

Age-related changes of arteries, veins, glands, and stroma in the prostate of black men from Washington, DC, and from Ibadan, Nigeria, and Accra, Ghana, West AFrica, were studied in a total of 795 consecutive, unselected prostate specimens removed at autopsy during a 7-year period (1973-1980). Except for age group 80 and over, aging changes in the prostate were more severe in all age groups in black men from Washington, DC, than in black men from Ibadan and Accra (P less than 0.01). However, when the intensity of age-dependent alterations was compared in either US or African black men with carcinoma and with no carcinoma, no significant differences were found. These findings do not support the idea that the aging process per se increases susceptibility to cancer.