Diet effects on mouse meiotic recombination: a warning for recombination studies.

Meiotic recombination is a critical process for sexually reproducing organisms. This exchange of genetic information between homologous chromosomes during meiosis is important not only because it generates genetic diversity, but also because it is often required for proper chromosome segregation. Consequently, the frequency and distribution of crossovers are tightly controlled to ensure fertility and offspring viability. However, in many systems, it has been shown that environmental factors can alter the frequency of crossover events. Two studies in flies and yeast point to nutritional status affecting the frequency of crossing over. However, this question remains unexplored in mammals. Here, we test how crossover frequency varies in response to diet in Mus musculus males. We use immunohistochemistry to estimate crossover frequency in multiple genotypes under two diet treatments. Our results indicate that while crossover frequency was unaffected by diet in some strains, other strains were sensitive even to small composition changes between two common laboratory chows. Therefore, recombination is both resistant and sensitive to certain dietary changes in a strain-dependent manner and, hence, this response is genetically determined. Our study is the first to report a nutrition effect on genome-wide levels of recombination. Moreover, our work highlights the importance of controlling diet in recombination studies and may point to diet as a potential source of variability among studies, which is relevant for reproducibility.

Immunohistochemical analysis of low-grade and high-grade prostate carcinoma: relative changes of parathyroid hormone-related protein and its parathyroid hormone 1 receptor, osteoprotegerin and receptor activator of nuclear factor-kB ligand.

AIM: To investigate multiple bone cytokines produced by prostate carcinoma (PCa) as a novel strategy to differentiate potential aggressiveness in localised PCa using immunohistochemical analysis. METHODS: A total of 47 cases of PCa undergoing radical prostatectomy or transurethral prostatic resection at our institution (Fundación Jiménez Díaz (Grupo Capio), Madrid, Spain) between January 1991 and June 1998 were identified as low-grade (< or =4; n = 22) or high-grade (> or =7, excluding 7 (3+4) cases; n = 25) PCa according to Gleason grade. PCa specimens were immunostained for: parathyroid hormone (PTH)-related protein (PTHrP), the PTH1 receptor, osteoprotegerin and receptor activator of nuclear factor-kappa B ligand (RANKL), as well as Ki67 (a proliferation marker) and CD34 (an angiogenesis marker). RESULTS: PCa samples showed an increased immunostaining for both osteoprotegerin and RANKL, associated with tumour grade and PTHrP positivity, in the tumoral epithelium. Using a score value of 4-corresponding to moderate staining - as cut-off, the best sensitivity value was for PTHrP (with C-terminal antiserum C6; 100 %); wheras the best specificity value was for RANKL (95 %). CONCLUSIONS: All the evaluated factors are overexpressed mainly in the high-grade tumours. Our findings indicate that, in most patients with PCa (with Ki67 values between 1% and 9%), sequential determination of C-terminal PTHrP and RANKL immunoreactivities is a useful approach to discriminate low-grade and high-grade tumours.

Nodular herpes zoster with herpetic syringitis and no epidermal involvement in a patient with Burkitt lymphoma.

Herpes zoster (HZ) occurs with an increased incidence in immunosuppressed patients, in whom it frequently displays atypical clinical presentations. Herpetic syringitis, the involvement of the eccrine epithelium by herpes virus infection, is an infrequently described histologic pattern that has been rarely and almost exclusively reported in HIV-infected patients. We report the case of a woman with Burkitt lymphoma who developed 2 nodular, asymptomatic lesions while receiving treatment with chemotherapy and radiotherapy for her hematological disease. Histology showed viropathic changes in the epithelium of eccrine glands not in the epidermis. PCR was positive for varicella-zoster virus (VZV). Nodular herpes zoster seems to be an exceptional clinical presentation. We report another such case which is, as far as we know, the first report of herpetic syringitis with no concomitant epidermal involvement.

[Bladder leiomyoma in a male patient]. / Leiomioma vesical en un varón.

OBJECTIVES: Bladder leiomyoma is an uncommon mesenchymal benign tumor. It is generally asymptomatic and incidentally detected. METHODS: We report a new case managed with transurethral resection without evidence of relapse. A bibliographic search was performed to evaluate the diagnostic techniques, clinical features and treatment options of this rare disease. CONCLUSIONS: Bladder leiomyoma is a benign mesenchymal tumor originating from smooth muscle. Biopsy and histological study are required for definitive diagnosis. Surgery is the treatment of choice, and it has an excellent prognosis if resection is complete.

[Localized amyloidosis of the seminal vesicles]. / Amiloidosis localizada de vesículas seminales.

Amyloidosis of the seminal vesicles is a common finding in autopsies, with increased incidence in older population. It is usually asymptomatic. We report a case of symptomatic localized amyloidosis of the seminal vesicles, with hemospermia and suprapubic pain. Diagnosis was achieved through ultrasound-guided transrectal biopsy. Systemic amyloidosis must be ruled out through proper evaluation. Seminal vesicle enlargement secondary to amyloid deposit may be misdiagnosed as carcinomatous invasion.