Treatment Effects and Risk Factors Evaluation in Longitudinal Studies : A Statistical Help for Data Analysis

This paper was inspired by the experience of the Authors research group composed by oncologist veterinarians and a biostatistician to evaluate treatments and prognostic factors with the aim to help veterinarians involved in longitudinal studies into evaluating and writing prognostic results. Longitudinal studies are commonly analysed by techniques for survival data, taking into account for the time elapsed from the beginning of observation and the occurrence of an event related to treatment effect or disease course. The presence of incomplete follow-up information for some subjects requires specific descriptive and inferential statistical methods. Two literature datasets were analysed to show statistical models implementation techniques and to discuss statistical issues: I) A multicentre clinical trial on remission maintenance of children with acute Lymphoblastic leukaemia and II) A randomized clinical trial on advanced inoperable lung cancer. Data sets concerned studies on \u201chumans\u201d, nevertheless the peculiar data structure allowed to discuss some aspects which are common to survival analysis studies, regardless on subject\u2019s characteristics. Log-rank test was used to compare survival curves for treatments and the relationship between Log-Rank test and univariate Cox model results was explained. As the evaluation of prognostic impact cannot be based only on p-values, the strength of the association between treatments and prognosis was estimated to take into account for the clinical relevance of results. On the second data set, beside of treatment, other clinical variables were available and a multivariate Cox model was applied. Model implementation was discussed concerning the coding of categorical variables and the relationship between continuous variables and model response. Suggested rules for the maximum number of covariates to be included in order to obtain reliable results were cited. Finally, the predictive ability of the model was discussed based on a measure of the area under ROC curve specific for survival data

Nefopam, an analogue of orphenadrine, protects against both NMDA receptor-dependent and independent veratridine-induced neurotoxicity

Nefopam hyghochloride is a potent analgesic compound commercialized in most Western Europe for 20 years, which possesses a profile distinct from that of opioids or anti-inflammatory drugs. Previous evidence suggested a central action of nefopam but the detailed mechanisms remain unclear. While, nefopam structure resembles that of orphenadrine, an uncompetitive NMDA receptor antagonist, here we report that differently from orphenadrine, nefopam (100 microM) failed to protect cultured cerebellar neurons from excitotoxicity following direct exposure of neurons to glutamate. Moreover, nefopam failed to displace MK-801 binding to hippocampal membranes. Nefopam effectively prevented NMDA receptor-mediated early appearance (30 min) of toxicity signs induced by the voltage sensitive sodium channel (VSSC) activator veratridine. The later phase (24 h) of neurotoxicity by veratridine occurring independently from NMDA receptor activation, was also prevented by nefopam. Nefopam effect was not mimicked by the GABA receptor agonist muscimo

Novel effect of nefopam preventing cGMP increase, oxygen radical formation and neuronal death induced by veratridine

Nefopam hydrochloride is a potent analgesic compound that possesses a profile distinct from that of opiods or anti-inflammatory drugs. Previous evidence suggested a central action of nefopam but the detailed mechanisms remain unclear. Here we have used cultured cerebellar neurons to test the hypothesis that nefopam may modulate voltage sensitive sodium channel (VSSC) activity. Nefopam (100 microM) effectively prevented NMDA receptor-mediated early appearance (30 min) of toxicity signs induced by the VSSC activator veratridine. Delayed neurotoxicity by veratridine occurring independently from NMDA receptor activation, was also prevented by nefopam. In contrast, excitotoxicity following direct exposure of neurons to glutamate was not affected. Neuroprotection by nefopam was dose-dependent. 50% protection was obtained at 57 microM while full neuroprotection was achieved at 75 microM nefopam. Veratridine-induced sodium influx was completely abolished in nefopam-treated neurons. Intracellular cGMP and oxygen radical formation following VSSC stimulation by veratridine were also effectively prevented by nefopam. Our data are consistent with an inhibitory action of nefopam on VSSC and suggest that nefopam may modulate the release of endogenous glutamate following activation of these channels. This novel action of nefopam may be of great interest for the treatment of neurodegenerative disorders involving excessive glutamate release and neurotransmission

Evaluation of short‐term safety of ultrasound‐guided foetal fluid sampling in the dog (Canis lupus familiaris)

Background: In humans, analysis of amniotic fluid is widely used for diagnostic and prognostic purposes. Amniocentesis has scarcely been used in veterinary medicine to date, despite a tremendous potential for clinical and research applications in dogs. Our study aimed to establish a safe method for foetal fluid sampling in female dogs. Methods: Two transabdominal ultrasound-guided methods were assessed: the "free hand" and the needle-guided bracket sampling. In addition, through a subsequent routinely scheduled ovariohysterectomy, fluid was directly collected. Samples from 98 conceptuses were collected at day 46.7 +/- 7.5 of pregnancy. Results: The amount of fluid retrieved varied between 0.5 and 5.0 ml per collection. Macroscopic examination of the uterus and conceptuses identified 53% of the puncture sites. Neither fluid leakage nor foetal injury was detected, and six hematomas (5.8%) were visible. Ultrasound-guided foetal fluid collection was found to be potentially safe, and it can be performed by using either transabdominal method. Conclusion: Foetal fluid collection is possible with relative ease and low short-term risk, and may open paths for diagnostic, therapeutic and research purposes in dogs. The procedure can provide new insights into prenatal clinical medicine, including diagnostics of foetal deaths, early identification of heritable diseases and so on

On a Genetic Multiobjective Approach for the Integration and Optimization of Assembly Product Design and Process Planning

2nonenoneR. GROPPETTI; MUSCIA R.R., Groppetti; Muscia, Robert