A Synaptic Mechanism for Temporal Filtering of Visual Signals

The visual system transmits information about fast and slow changes in light intensity through separate neural pathways. We used in vivo imaging to investigate how bipolar cells transmit these signals to the inner retina. We found that the volume of the synaptic terminal is an intrinsic property that contributes to different temporal filters. Individual cells transmit through multiple terminals varying in size, but smaller terminals generate faster and larger calcium transients to trigger vesicle release with higher initial gain, followed by more profound adaptation. Smaller terminals transmitted higher stimulus frequencies more effectively. Modeling global calcium dynamics triggering vesicle release indicated that variations in the volume of presynaptic compartments contribute directly to all these differences in response dynamics. These results indicate how one neuron can transmit different temporal components in the visual signal through synaptic terminals of varying geometries with different adaptational properties

Hepatitis B virus infection among pregnant women in Taiwan: Comparison between women born in Taiwan and other southeast countries

<p>Abstract</p> <p>Background</p> <p>Taiwan's national vaccination program has successfully decreased the prevalence of hepatitis B infection after twenty years of implementation and might be indirectly beneficial to the second generation. In this study, we compared the hepatitis B infection status of two groups: pregnant Taiwanese women and other Southeast Asian women, who because they had immigrated later in life to Taiwan by marriage to a Taiwanese man, had not been exposed to that vaccination program to evaluate the effect of hepatitis vaccination program on women of child-bearing age and further explored the potential impact of immigration on the hepatitis B public health policy in Taiwan.</p> <p>Methods</p> <p>Data was collected from 10,327 women born in Taiwan and 1,418 women born in other Southeast Asian countries, both groups receiving prenatal examinations at Fooyin University Hospital between 1996 and 2005. The results of serum hepatitis B s-Antigen (HBsAg) and hepatitis B e-Antigen (HBeAg) tests and other demographic data were obtained by medical chart review.</p> <p>Results</p> <p>The pregnant women from Taiwan had a higher HBsAg positive rate (15.5%) but lower HBeAg(+)/HBsAg(+) ratio (32.1%) than the women from other countries (8.9% and 52.4%). For those born before July, 1984, the period of no national vaccination program, Taiwanese women had a higher HBsAg positive rate than other Southeast Asian women (15.7% vs. 8.4%), but for women born after that day and before June 1986, the period of vaccination for high risk newborns, the HBsAg positive rates found to be slightly lower for Taiwanese women than for other Southeast Asian women (11.4% vs. 12.3%) and the difference was more significant (3.1% vs. 28.6%) after June 1986, the period of vaccination for all newborns. While the HBeAg(+)/HBsAg(+) ratios decreased with age in both groups, they were consistently higher in women from other Southeast Asian countries than in women born in Taiwan after age 20.</p> <p>Conclusion</p> <p>In Taiwan, the neonatal vaccination program that was implemented in 1984 has successfully reduced hepatitis B infection among pregnant women in present day, and is likely to indirectly prevent hepatitis B infection in the next generation. However, the increasing number of pregnant women from other Southeast Asian countries without a national neonatal vaccination program or with a program that was introduced later than the one in Taiwan will likely lessen the positive impact of this program and should be further assessed.</p

Cardiomyocyte-specific inactivation of thyroid hormone in pathologic ventricular hypertrophy: an adaptative response or part of the problem?

Recent studies in various rodent models of pathologic ventricular hypertrophy report the re-expression of deiodinase type 3 (D3) in cardiomyocytes. D3 inactivates thyroid hormone (T3) and is mainly expressed in tissues during development. The stimulation of D3 activity in ventricular hypertrophy and subsequent heart failure is associated with severe impairment of cardiac T3 signaling. Hypoxia-induced signaling appears to drive D3 expression in the hypertrophic cardiomyocyte, but other signaling cascades implicated in hypertrophy are also capable of stimulating transcription of the DIO3 gene. Many cardiac genes are transcriptionally regulated by T3 and impairment of T3 signaling will not only reduce energy turnover, but also lead to changes in gene expression that contribute to contractile dysfunction in pathologic remodeling. Whether stimulation of D3 activity and the ensuing local T3-deficiency is an adaptive response of the stressed heart or part of the pathologic signaling network leading to heart failure, remains to be established

Technique of spinal cord compression induced by inflation of epidural balloon catheter in rabbits (Oryctologus cuniculus): efficient and easy to use model

ABSTRACT The most common cause of spinal cord injury are high impact trauma, which often result in some motor impairment, sensory or autonomic a greater or lesser extent in the distal areas the level of trauma. In terms of survival and complications due to sequelae, veterinary patients have a poor prognosis unfavorable. Therefore justified the study of experimental models of spinal cord injury production that could provide more support to research potential treatments for spinal cord injuries in medicine and veterinary medicine. Preclinical studies of acute spinal cord injury require an experimental animal model easily reproducible. The most common experimental animal model is the rat, and several techniques for producing a spinal cord injury. The objective of this study was to describe and evaluate the effectiveness of acute spinal cord injury production technique through inflation of Fogarty(r) catheter using rabbits as an experimental model because it is a species that has fewer conclusive publications and contemplating. The main requirements of a model as low cost, handling convenience, reproducibility and uniformity. The technique was adequate for performing preclinical studies in neuro-traumatology area, effectively leading to degeneration and necrosis of the nervous tissue fostering the emergence of acute paraplegia

Autologous haematopoietic stem cell transplantation for treatment of multiple sclerosis

Autologous haematopoietic stem cell transplantation (AHSCT) is a multistep procedure that enables destruction of the immune system and its reconstitution from haematopoietic stem cells. Originally developed for the treatment of haematological malignancies, the procedure has been adapted for the treatment of severe immune-mediated disorders. Results from ~20 years of research make a compelling case for selective use of AHSCT in patients with highly active multiple sclerosis (MS), and for controlled trials. Immunological studies support the notion that AHSCT causes qualitative immune resetting, and have provided insight into the mechanisms that might underlie the powerful treatment effects that last well beyond recovery of immune cell numbers. Indeed, studies have demonstrated that AHSCT can entirely suppress MS disease activity for 4–5 years in 70–80% of patients, a rate that is higher than those achieved with any other therapies for MS. Treatment-related mortality, which was 3.6% in studies before 2005, has decreased to 0.3% in studies since 2005. Current evidence indicates that the patients who are most likely to benefit from and tolerate AHSCT are young, ambulatory and have inflammatory MS activity. Clinical trials are required to rigorously test the efficacy, safety and cost-effectiveness of AHSCT against highly active MS drugs

Assessment of age-related changes in pediatric gastrointestinal solubility

PurposeCompound solubility serves as a surrogate indicator of oral biopharmaceutical performance. Between infancy and adulthood, marked compositional changes in gastrointestinal (GI) fluids occur. This study serves to assess how developmental changes in GI fluid composition affects compound solubility.MethodsSolubility assessments were conducted in vitro using biorelevant media reflective of age-specific pediatric cohorts (i.e., neonates and infants). Previously published adult media (i.e., FaSSGF, FeSSGF, FaSSIF.v2, and FeSSIF.v2) were employed as references for pediatric media development. Investigations assessing age-specific changes in GI fluid parameters (i.e., pepsin, bile acids, pH, osmolality, etc.) were collected from the literature and served to define the composition of neonatal and infant media. Solubility assessments at 37°C were conducted for seven BCS Class II compounds within the developed pediatric and reference adult media.ResultsFor six of the seven compounds investigated, solubility fell outside an 80–125% range from adult values in at least one of the developed pediatric media. This result indicates a potential for age-related alterations in oral drug performance, especially for compounds whose absorption is delimited by solubility (i.e., BCS Class II).ConclusionDevelopmental changes in GI fluid composition can result in relevant discrepancies in luminal compound solubility between children and adults.<br/