Aspects of the protein and the lipid composition of myelinoid marchi-positive bodies from mammalian spinal cord

The fraction floating on 0.32 M sucrose was isolated from normal mammalian spinal cord and analyzed with regard to protein and lipid composition. Comparisons were made with the myelin fraction isolated from the same spinal cord. A close relationship between the two fractions was indicated by a similar protein banding on SDS-polyacrylamide gel electrophoresis. The relative amounts of various proteins however were different and some high molecular weight proteins appeared unique to the floating fraction. The phospho- and galactolipid patterns, as revealed by thin-layer chromatography, were similar in the floating and the myelin fractions. The proportion of hydrophobic lipids, such as sterols and isoprenyl derivatives, was higher in the floating fraction. Bands co-migrating with cholesterol esters were detected only in the floating fraction from guinea pigs. Marchi-positive material of possible paranodal origin is enriched in the floating fraction. The present findings of a biochemical composition of the floating fraction closely resembling that of myelin is in line with the view that myelin turnover includes a step of degradation localized to the paranodal regions.     

Detection of FP Plasmids in Hospital Isolates of Pseudomonas aeruginosa

A simple method of detection of FP plasmids with chromosome-mobilizing ability in Pseudomonas aeruginosa has been developed.     

Involvement of L-type calcium channels and mitochondria in post-tetanic potentiation: Is it a general rule for different types of synapses?

Our experiments and studies of a few other authors demonstrated that L-type calcium channels and mitochondria are involved in the induction of post-tetanic potentiation (PTP) in a number of preparations (Aplysia central nervous system, hippocampal cell cultures, crayfish neuromuscular junctions, etc.). We extend this conclusion on cortical synapses by the demonstration that inhibitors of mitochondrial Ca²⁺ uptake and release suppress PTP in rat neocortical cell cultures. Neirofiziologiya/Neurophysiology, Vol. 39, Nos. 4/5, pp. 403–404, July–October, 2007.     

Western Notions of Informed Consent and Indigenous Cultures: Australian Findings at the Interface

Despite the extensive consideration the notion of informed consent has heralded in recent decades, the unique considerations pertaining to the giving of informed consent by and on behalf of Indigenous Australians have not been comprehensively explored; to the contrary, these issues have been scarcely considered in the literature to date. This deficit is concerning, given that a fundamental premise of the doctrine of informed consent is that of individual autonomy, which, while privileged as a core value of non-Indigenous Australian culture, is displaced in Indigenous cultures by the honouring of the family unit and community group, rather than the individual, as being at the core of important decision-making processes relating to the person. To address the hiatus in the bioethical literature on issues relating to informed consent for Aboriginal peoples, the following article provides findings from a two-year research project, funded by Australia’s National Health and Medical Research Council (NHMRC), conducted in the Northern Territory. The findings, situated in the context of the literature on cultural safety, highlight the difference between the Aboriginal and biomedical perspectives on informed consent.     

Multiple phenotypic changes in mice after knockout of the <Emphasis Type="Italic">B3gnt5</Emphasis>gene,encoding Lc3 synthase—a key enzyme in lacto-neolacto ganglioside synthesis

Background  

Ganglioside biosynthesis occurs through a multi-enzymatic pathway which at the lactosylceramide step is branched into several biosynthetic series. Lc3 synthase utilizes a variety of galactose-terminated glycolipids as acceptors by establishing a glycosidic bond in the beta-1,3-linkage to GlcNaAc to extend the lacto- and neolacto-series gangliosides. In order to examine the lacto-series ganglioside functions in mice, we used gene knockout technology to generate Lc3 synthase gene B3gnt5-deficient mice by two different strategies and compared the phenotypes of the two null mouse groups with each other and with their wild-type counterparts.     

Functional Imaging of Auditory Cortex in Adult Cats using High-field fMRI

Current knowledge of sensory processing in the mammalian auditory system is mainly derived from electrophysiological studies in a variety of animal models, including monkeys, ferrets, bats, rodents, and cats. In order to draw suitable parallels between human and animal models of auditory function, it is important to establish a bridge between human functional imaging studies and animal electrophysiological studies. Functional magnetic resonance imaging (fMRI) is an established, minimally invasive method of measuring broad patterns of hemodynamic activity across different regions of the cerebral cortex. This technique is widely used to probe sensory function in the human brain, is a useful tool in linking studies of auditory processing in both humans and animals and has been successfully used to investigate auditory function in monkeys and rodents. The following protocol describes an experimental procedure for investigating auditory function in anesthetized adult cats by measuring stimulus-evoked hemodynamic changes in auditory cortex using fMRI. This method facilitates comparison of the hemodynamic responses across different models of auditory function thus leading to a better understanding of species-independent features of the mammalian auditory cortex.     

Serum-converted platelet lysate can substitute for fetal bovine serum in human mesenchymal stromal cell cultures

Background aimsFetal bovine serum (FBS) is commonly used as a serum supplement for culturing human mesenchymal stromal cells (hMSCs). However, human cells grown in FBS, especially for extended periods, risk potential exposure to bovine immunogenic proteins and infectious agents. To address this issue, we investigated the ability of a novel human platelet serum supplement to substitute for FBS in hMSC cultures.MethodsPlatelet lysate-serum (PL-serum) was converted from platelet lysate-plasma (PL-plasma) that was manufactured from pooled platelet-rich plasma (PRP) apheresis units. Growth factor levels and the number of residual intact platelets in PL-serum and PL-plasma were compared with enzyme-linked immunosorbent assays and flow cytometry, respectively. Proliferation responses of hMSCs cultured in PL-serum, PL-plasma, or FBS were assessed with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, the immunophenotype of harvested hMSCs was evaluated by flow cytometry and tri-lineage differentiation potential was evaluated by assessing adipogenic, osteogenic and chondrogenic development.ResultsSelected growth factor levels in PL-serum were not significantly different from PL-plasma (P > 0.05). hMSC cultures supplemented with PL-serum had comparable growth kinetics to PL-plasma, and hMSC yields were consistently greater than with FBS. hMSCs harvested from cultures supplemented with PL-serum, PL-plasma or FBS had similar cell surface phenotypes and maintained tri-lineage differentiation potential.ConclusionsPL-serum, similar to PL-plasma, can substitute for FBS in hMSC cultures. Use of PL-serum, in contrast to PL-plasma, has an added advantage of not requiring addition of a xenogeneic source of heparin, providing a completely xeno-free culture medium.