Definition of valid proteomic biomarkers: a bayesian solution

Clinical proteomics is suffering from high hopes generated by reports on apparent biomarkers, most of which could not be later substantiated via validation. This has brought into focus the need for improved methods of finding a panel of clearly defined biomarkers. To examine this problem, urinary proteome data was collected from healthy adult males and females, and analysed to find biomarkers that differentiated between genders. We believe that models that incorporate sparsity in terms of variables are desirable for biomarker selection, as proteomics data typically contains a huge number of variables (peptides) and few samples making the selection process potentially unstable. This suggests the application of a two-level hierarchical Bayesian probit regression model for variable selection which assumes a prior that favours sparseness. The classification performance of this method is shown to improve that of the Probabilistic K-Nearest Neighbour model

Comparação entre duas concentrações de glicerol para a criopreservação de sêmen de suçuarana (Puma concolor)

O desenvolvimento de biotécnicas de reprodução é uma importante ferramenta para a conservação de animais silvestres ameaçados de extinção. Procedimentos de reprodução assistida em suçuarana, no entanto, são escassos na literatura, em especial aqueles relacionados à criopreservação de sêmen. Neste sentido, o presente trabalho objetivou avaliar a congelabilidade do sêmen de suçuaranas adultas mantidas em cativeiro, por meio da comparação entre duas concentrações de glicerol no meio de congelamento. Foram usados cinco machos adultos de suçuarana, mantidos no Centro de Reabilitação de Animais Silvestres do Mato Grosso do Sul (CRAS/MS). As amostras foram coletadas por eletroejaculação e avaliadas quanto ao seu aspecto físico, volume, vigor, motilidade, concentração e índice espermático. De cada ejaculado duas alíquotas foram diluídas em meio Tris-citrato-gema de ovo, em concentrações finais de 5 e 7,5% de glicerol, resfriadas a uma taxa de -0,55ºC/min e congeladas a uma taxa de -5,8ºC/min. Depois de descongeladas, as amostras foram reavaliadas e submetidas aos testes de termorresistência e hiposmótico. O protocolo de criopreservação e descongelamento de sêmen proposto se mostrou eficiente em ambas as concentrações de glicerol testadas, não havendo diferença (p>0,05) entre estas

Snoring, sleep disturbance, and behaviour in 4-5 year olds.

Parents of 996 children aged 4-5 years identified consecutively from the Oxford health visitor register were asked to complete a questionnaire about breathing disorders during sleep. A total of 782 (78.5%) was returned. Ninety five (12.1%) children were reported to snore on most nights. Habitual snoring was significantly associated with daytime sleepiness, restless sleep, and hyperactivity. The questionnaire responses were used to select two subgroups, one at high risk of a sleep and breathing disorder and a control group. These children (132 in total) were monitored at home with overnight video recording and oximetry, and had formal behavioural assessment using the Conners scale. Seven (7/66) children from the high risk group and none from the control group had obvious sleep disturbance consequent on snoring and upper airway obstruction. Thus our estimate of the prevalence of sleep and breathing disorders in this age group is 7/996 or 0.7%. The high risk group had significantly higher nocturnal movement, oxygen saturation dip rates, and overnight pulse rates than the controls. Maternal but not paternal smoking was associated with the high risk group. Parents and teachers thought those in the high risk group were more hyperactive and inattentive than the controls, but only their parents thought them more aggressive. Significant sleep and breathing disorders occur in about 0.7% of 4-5 year olds. Children whose parents report snoring and sleep disturbance have objective evidence of sleep disruption and show more behaviour problems than controls

RNA Interference: Its Use as Antiviral Therapy

RNA interference (RNAi) is a sequence-specific gene-silencing mechanism that has been proposed to function as a defence mechanism of eukaryotic cells against viruses and transposons. RNAi was first observed in plants in the form of a mysterious immune response to viral pathogens. But RNAi is more than just a response to exogenous genetic material. Small RNAs termed microRNA (miRNA) regulate cellular gene expression programs to control diverse steps in cell development and physiology. The discovery that exogenously delivered short interfering RNA (siRNA) can trigger RNAi in mammalian cells has made it into a powerful technique for generating genetic knock-outs. It also raises the possibility to use RNAi technology as a therapeutic tool against pathogenic viruses. Indeed, inhibition of virus replication has been reported for several human pathogens including human immunodeficiency virus, the hepatitis B and C viruses and influenza virus. We reviewed the field of antiviral RNAi research in 2003 (Haasnoot et al. 2003), but many new studies have recently been published. In this review, we present a complete listing of all antiviral strategies published up to and including December 2004. The latest developments in the RNAi field and their antiviral application are describe