Steroid 5-alpha reductase type 2 activity in biopsies from malignant and normal prostatic tissues.

BACKGROUND: The conversion of testosterone (T) to the more potent metabolite dihydrotestosterone (DHT) by prostate-specific steroid 5 alpha-reductase isoenzymes is a key mechanism in the action of androgens in the prostate and it is important in the promotion and progression of prostate diseases. We described an adaptation of a sensitive method for evaluation of the 5 alpha-reductase type 2 (5 alpha-R2) activity using a small quantity of protein. METHODS: We used 29 human prostate transrectal ultrasound-guided core biopsies obtained from patients (median age 70, range 55-86 y) undergoing this procedure for diagnostic purposes. 4-[(14)C]testosterone and NADPH were incubated with biopsy homogenate. Reaction products were extracted, separated by thin layer chromatography and revealed by autoradiography. Areas correspondent to T and DHT were scraped into vials and their radioactivity determined. RESULTS: The 5 alpha-R2 activity was expressed as ln (natural logarithm). The assay was validated according to the protein concentration and incubation time linearities. The 5 alpha-R2 activity showed a significant difference between normal and neoplastic tissues with significance level set at P<0.05, mainly in the left prostate lobe. This was independent from the PSA levels. CONCLUSIONS: Determination of 5 alpha-R2 activity, using the conditions reported herein, could be utilized as an efficient biochemical parameter of prostate neoplastic processes.

Neonatal hypoxia-ischemia reduces ganglioside, phospholipid and cholesterol contents in the rat hippocampus.

Hypoxia-ischemia is a common cause of neonatal brain damage producing serious impact on cerebral maturation. This report demonstrates that rats submitted to hypoxia-ischemia present a marked decrease in hippocampal gangliosides, phospholipids and cholesterol contents as from 7 days after the injury. Although chromatographic profiles of the different ganglioside species (GM1, GD1a, GD1b, and GT1b) from the hippocampus of hypoxic-ischemic hippocampi groups (HI) were apparently unaffected, as compared with controls, there were quantitative absolute reductions in HI. The phospholipid patterns were altered in HI as from the 14th to the 30th day after the injury, where phosphatidylcholine (PC) quantities were higher than phosphatidylethanolamine (PE); additionally, the cardiolipin band was detected only in hippocampi of control adult rats. In general, the absolute quantities of phospholipids were lower in HI than in correspondent controls since 7th day after the injury. Considering that reported effects were maintained, we suggest they express a late biochemical response triggered by the neonatal hypoxic-ischemic episode; the consequences would be cell death and a delay on brain development, expressed by a reduction on synaptogenesis and myelinogenesis processes.

Adaptation of an evaluation method of 5 alpha-reductase type 1 and type 2 enzyme activities in prostate tissue

Objectives: We are proposing the adaptation of a method for the assessment of the activity of 5 alpha-reductase type 1 and type 2 isoenzymes in human prostate tissue to be used in studies of the relationship of enzymatic activity and cancer. Material and Methods: We have been developing a method, based on Thomas et al., 2003 which consists of collecting human prostate samples and performing 5 alpha-reductase activity assessment. We are proposing a method based on samples obtained from prostate biopsies, according to a pilot study developed by Oliveira et al. 2006. We have obtained two samples of the same prostate area, and our idea is to send one of these samples for pathological examination and another for 5 alpha-reductase evaluation. Herein we have showed the feasibility of this assay. Through a thin layer chromatography with 14C-testosterone and NADPH (nicotinamide adenine dinucleotide phosphate) cofactor, we have obtained radioactive spots which were detected by autoradiography. The areas associated with testosterone and its metabolite DHT (dihydrotestosterone) were scrapped and counted with a scintillation chamber. Results: We believe that it is possible to demonstrate the activity of 5 alpha-reductase through the adaptation of this biochemistry method. Conclusions: This method is feasible and can be utilized to assess 5 alpha-reductase type 1 and type 2 activity in prostate tissue samples.

Efeito da leucocitospermia na análise do sêmen / Effect of polymorphonuclear leucocites on semen analisys

A infertilidade conjugal é um problema que afeta muitos casais e há diversos procedimentos clínicos e laboratoriais para investigar sua etiologia. O exame do sêmen é um procedimento comumente adotado nesta investigação, pois sua análise contribui significativamente para avaliar o fator masculino. Este estudo visou verificar o efeito dos leucócitos em parâmetros rotineiramente analisados no espermograma, que incluiem a concentração, motilidade e morfologia dos espermatozóides. Os polimorfonucleares (PMN) foram marcados pela técnica de peroxidase, e as 90 amostras de sêmen de homens submetidos à triagem de infertilidade foram divididas em dois grupos, de acordo com a concentração de leucócitos: as de pacientes leucocitospérmicos (concentração superior a 1x10 6/ml de sêmen). Observou-se um aumento da concentração de espermatozóides com a presença de leucócitos e o percentual de espermatozóides móveis/imóveis e anormais não foi alterado. De maneira geral, a leucocitospermia não altera a qualidade do sêmen.