Objective assessment of the cryoprotective effects of dimethylformamide for freezing goat semen

AbstractThe aim of this work was to assess the cryoprotective effects of dimethylformamide (DMF) for freezing goat semen, using an objective analysis by computer-assisted sperm analysis (CASA). Twenty-one ejaculates (seven per animal) were collected from three stud bucks with the aid of an artificial vagina and immediately evaluated for gross and microscopic characteristics. The semen was diluted in two steps with a Tris–egg yolk extender containing 6% glycerol or 6% DMF, frozen in 0.50-mL straws, and stored in liquid nitrogen. Samples were accessed for sperm morphology, sperm membrane structural and functional integrity, and by CASA, immediately after thawing. There were differences (P<0.05) between glycerol and DMF with regard to subjective progressive motility (23.9±2.2% vs. 16.6±2.0%), objective progressive motility (3.5±0.4% vs. 1.8±0.3%), linearity (53.9±1.6% vs. 48.1±1.4%) and amplitude of lateral head (2.3±0.1 vs. 2.9±0.1mm), which confirmed the efficiency of glycerol. In conclusion, dimethylformamide could be used as an alternative cryoprotectant for goat semen freezing. However it was showed that no benefits were derived by using dimethylformamide to replace glycerol at an equal 6% concentration

Osteopenia Due to Enhanced Cathepsin K Release by BK Channel Ablation in Osteoclasts

BACKGROUND: The process of bone resorption by osteoclasts is regulated by Cathepsin K, the lysosomal collagenase responsible for the degradation of the organic bone matrix during bone remodeling. Recently, Cathepsin K was regarded as a potential target for therapeutic intervention of osteoporosis. However, mechanisms leading to osteopenia, which is much more common in young female population and often appears to be the clinical pre-stage of idiopathic osteoporosis, still remain to be elucidated, and molecular targets need to be identified. METHODOLOGY/PRINCIPAL FINDINGS: We found, that in juvenile bone the large conductance, voltage and Ca(2+)-activated (BK) K(+) channel, which links membrane depolarization and local increases in cytosolic calcium to hyperpolarizing K(+) outward currents, is exclusively expressed in osteoclasts. In juvenile BK-deficient (BK(-/-)) female mice, plasma Cathepsin K levels were elevated two-fold when compared to wild-type littermates. This increase was linked to an osteopenic phenotype with reduced bone mineral density in long bones and enhanced porosity of trabecular meshwork in BK(-/-) vertebrae as demonstrated by high-resolution flat-panel volume computed tomography and micro-CT. However, plasma levels of sRANKL, osteoprotegerin, estrogene, Ca(2+) and triiodthyronine as well as osteoclastogenesis were not altered in BK(-/-) females. CONCLUSION/SIGNIFICANCE: Our findings suggest that the BK channel controls resorptive osteoclast activity by regulating Cathepsin K release. Targeted deletion of BK channel in mice resulted in an osteoclast-autonomous osteopenia, becoming apparent in juvenile females. Thus, the BK(-/-) mouse-line represents a new model for juvenile osteopenia, and revealed the BK channel as putative new target for therapeutic controlling of osteoclast activity

A systematic review of the literature examining the diagnostic efficacy of measurement of fractionated plasma free metanephrines in the biochemical diagnosis of pheochromocytoma

BACKGROUND: Fractionated plasma metanephrine measurements are commonly used in biochemical testing in search of pheochromocytoma. METHODS: We aimed to critically appraise the diagnostic efficacy of fractionated plasma free metanephrine measurements in detecting pheochromocytoma. Nine electronic databases, meeting abstracts, and the Science Citation Index were searched and supplemented with previously unpublished data. Methodologic and reporting quality was independently assessed by two endocrinologists using a checklist developed by the Standards for Reporting of Diagnostic Studies Accuracy Group and data were independently abstracted. RESULTS: Limitations in methodologic quality were noted in all studies. In all subjects (including those with genetic predisposition): the sensitivities for detection of pheochromocytoma were 96%–100% (95% CI ranged from 82% to 100%), whereas the specificities were 85%–100% (95% CI ranged from 78% to 100%). Statistical heterogeneity was noted upon pooling positive likelihood ratios when those with predisposition to disease were included (p < 0.001). However, upon pooling the positive or negative likelihood ratios for patients with sporadic pheochromocytoma (n = 191) or those at risk for sporadic pheochromocytoma (n = 718), no statistical heterogeneity was noted (p = 0.4). For sporadic subjects, the pooled positive likelihood ratio was 5.77 (95% CI = 4.90, 6.81) and the pooled negative likelihood ratio was 0.02 (95% CI = 0.01, 0.07). CONCLUSION: Negative plasma fractionated free metanephrine measurements are effective in ruling out pheochromocytoma. However, a positive test result only moderately increases suspicion of disease, particularly when screening for sporadic pheochromocytoma

Trypanosoma vivax nos tecidos testicular e epididimário de ovinos experimentalmente infectados

Quatro ovinos machos, com cerca de 12 meses de idade (Ovinos 1-4), foram infectados por via intravenosa com aproximadamente 1,25x10(5) tripomastigotas de Trypanosoma vivax, outros quatro ovinos (Ovinos 5-8) destinaram-se ao grupo controle. Após a infecção, exames clínicos visando avaliar temperatura retal, freqüências cardíaca e respiratória e parasitemia foram realizados diariamente por 30 dias, tempo estabelecido para o término do experimento. A avaliação do hematócrito foi realizada a cada cinco dias. Ao final do período experimental, os animais foram castrados e os testículos e epidídimos submetidos ao exame anatomopatológico. Amostras destes órgãos dos Ovinos 1, 4 e 5 foram tomadas para a realização da reação em cadeia da polimerase (PCR). Os parâmetros clínicos (hipertermia, aumento das freqüências cardíaca e respiratória, aumento de volume dos linfonodos e palidez das mucosas) mantiveram-se para o grupo infectado acima dos valores mostrados pelo grupo controle durante todo o período experimental. A parasitemia foi observada a partir do 3º dia pós-infecção (dpi) com picos nos 6-10os dpi e nos 15-18os dpi. Os Ovinos 1 e 4 apresentaram, a partir do 25º dpi, anemia acentuada. Macroscopicamente, todos os testículos dos animais do grupo infectado apresentaram-se flácidos e com coloração pálida. Microscopicamente, observaram-se degeneração testicular moderada a acentuada, epididimite multifocal e hiperplasia do epitélio epididimário. A análise por PCR de T. vivax nos tecidos testicular e epididimário resultou em 100% de positividade para ovinos infectados experimentalmente. As lesões epididimárias e testiculares associadas à presença do parasita nesses órgãos, detectada por PCR, sugerem a participação do parasita no mecanismo etiopatogênico de danos reprodutivos