Avaliação de alterações histopatológicas da próstata e séricas do PSA em ratos tratados com N-Metil-N-Nitrosureia e testosterona

A testosterona tem sido cada vez mais usada em homens na fase do envelhecimento como prevenção e tratamento de doenças metabólicas, melhora do desempenho sexual, proteção cardiovascular e manutenção da cognição. Porém ainda há conflito sobre seus efeitos na próstata com relação às doenças benignas e malignas. O presente estudo avaliou o efeito do tratamento com duas formas de testosterona sobre carcinoma de próstata induzido por N-Metil-N-Nitrosureia (NMU) a partir de análises histopatológicas e séricas do antígeno prostático específico (PSA). Para tal foram utilizados 80 ratos Wistar jovens, sadios, divididos em dois grupos (40 animais cada) tratados ou não com NMU intraperitoneal. Cada grupo foi dividido em quatro subgrupos iguais e tratados durante 16 semanas: 1) tratado com cipionato de testosterona a cada sete dias via intramuscular; 2) tratado com cipionato de testosterona a cada 14 dias via intramuscular; 3) tratado com undecanoato de testosterona oral diariamente; 4) tratado com óleo mineral. Após 16 semnanas e tratamento, os níveis do PSA não alteraram em nenhum grupo ou subgrupo e não houve desenvolvimento de tumores em nenhum deles. Portanto, as duas formas distintas de testosterona associada ao uso de NMU em curto espaço de tempo por via intraperitoneal não alteraram as dosagens séricas do PSA e não induziram a formação de tumores na próstata em ratos Wistar jovens e saudáveis. As alterações histopatológicas acinares encontradas nas próstatas foram projeção, secreção, congestão e inflamação, e as epiteliais foram: epitélio normal, redução do epitélio e redução na altura do mesmo. Tais achados colaboram para que outros estudos sejam realizados de maneira a orientar o uso de testosterona na prática clinica diária sem receio de indução do câncer na próstata.

Dwell time effect in peeling PSA laminates

Air, trapped interfacially between the adhesive and the substrate, can have a detrimental effect on the peel strength of bonds formed by a PSA and relatively impermeable adherends. If the adhesive wets the substrate surface so that the contact angle is small then the forces of the surface tension within the adhesive can lead to the gradual expulsion of these pockets of air and thereby to the enhancement of the peel strength-the dwell-time effect. Using a high-performance PSA transfer tape it has been found that this strengthening effect may operate over many thousands of hours. With increasing hydrophobicity of the surfaces, this effect can be suppressed and a poor peel strength remains essentially constant with time. The observed rates at which the peel strength increases are quantitatively consistent with diffusion of entrapped air out of the interface. © 2012 Copyright Taylor and Francis Group, LLC.

胚胎期光照和皮质酮对小鸡记忆影响的作用机制

It has been shown that prenatal light exposure and corticosterone improve memory retention of dark hatched chicks. The object of this study was to explore the neural mechanisms underlying the effect of prenatal light exposure and corticosterone on memory retention of chicks. To detect the effect of different prenatal treatments on memory retention of chicks, we used one-trial passive avoidance model. To examine the expression of glucocorticoid receptor (GR), neural cell adhesion molecule (NCAM), growth-associated protein 43 (GAP-43) and polysialic acid (PSA) in HV and LPO of chick brain, we used immunohistochemical method. Prenatal light exposure and glucocorticoid (corticosterone, dexamthesone) administered in embryonic day 20 (E20) markedly improve memory retention in dark hatched chicks. Light plays a critical role in improving memory. The critical exposure period is E19 and E20. The effect of these two hormones and light exposure can be significantly blocked by their receptor antagonist administration respectively. The light, corticosterone and particularly darkness significantly up-regulated the level of GR; the expression of NCAM and GAP-43 in HV and LPO peaked in E20 in normal hatched chicks and was significantly increased by light exposure and corticosterone. Protein synthesis inhibitor anisomycin markedly reduced the effect of light exposure but partially reduced the effect of corticosterone; light exposure and corticosterone in E20 significantly up-regulated PSA expression. Removing PSA from NCAM significantly retarded the effect of corticosterone on memory retention in chicks. Therefore, The effects of prenatal light exposure and corticosterone on memory retention are mediated via both corticosteroid receptors. The effects of both prenatal light and corticosterone might at first change the plasticity of the brain by up-regulation the synthesis and modification of proteins, and then influence the behavior performance of the chicks.

Failure to Achieve PSA Level ≤I ng/ml Following Neo-Adjuvant LHRHa Therapy Predicts for a Lower Biochemical Control Rate and Overall Survival in Localized Prostate Cancer Treated with Radiotherapy

PURPOSE: To investigate whether failure to suppress the prostate-specific antigen (PSA) level to /=2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy in patients scheduled to undergo external beam radiotherapy for localized prostate carcinoma is associated with reduced biochemical failure-free survival. METHODS AND MATERIALS: A retrospective case note review of consecutive patients with intermediate- or high-risk localized prostate cancer treated between January 2001 and December 2002 with neoadjuvant hormonal deprivation therapy, followed by concurrent hormonal therapy and radiotherapy was performed. Patient data were divided for analysis according to whether the PSA level in Week 1 of radiotherapy was 1 ng/mL in 52. At a median follow-up of 49 months, the 4-year actuarial biochemical failure-free survival rate was 84% vs. 60% (p = 0.0016) in favor of the patients with a PSA level after neoadjuvant hormonal deprivation therapy of 1 ng/mL at the beginning of external beam radiotherapy after >/=2 months of neoadjuvant luteinizing hormone-releasing hormone agonist therapy have a significantly greater rate of biochemical failure and lower survival rate compared with those with a PSA level of

Impact of PSA testing and prostatic biopsy on cancer incidence and mortality: comparative study between the Republic of Ireland and Northern Ireland

Objectives: To investigate the impact of different PSA testing policies and health-care systems on prostate cancer incidence and mortality in two countries with similar populations, the Republic of Ireland (RoI) and Northern Ireland (NI).

Methods: Population-level data on PSA tests, prostate biopsies and prostate cancer cases 1993–2005 and prostate cancer deaths 1979–2006 were compiled. Annual percentage change (APC) was estimated by joinpoint regression.

Results: Prostate cancer rates were similar in both areas in 1994 but increased rapidly in RoI compared to NI. The PSA testing rate increased sharply in RoI (APC = +23.3%), and to a lesser degree in NI (APC = +9.7%) to reach 412 and 177 tests per 1,000 men in 2004, respectively. Prostatic biopsy rates rose in both countries, but were twofold higher in RoI. Cancer incidence rates rose significantly, mirroring biopsy trends, in both countries reaching 440 per 100,000 men in RoI in 2004 compared to 294 in NI. Median age at diagnosis was lower in RoI (71 years) compared to NI (73 years) (p < 0.01) and decreased significantly over time in both countries. Mortality rates declined from 1995 in both countries (APC = -1.5% in RoI, -1.3% in NI) at a time when PSA testing was not widespread.

Conclusions: Prostatic biopsy rates, rather than PSA testing per se, were the main driver of prostate cancer incidence. Because mortality decreases started before screening became widespread in RoI, and mortality remained low in NI, PSA testing is unlikely to be the explanation for declining mortality.