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Investigation Support (investigation + support)
Selected AbstractsMatrix Regulation of Skeletal Cell Apoptosis II: Role of Arg-Gly-Asp-Containing PeptidesJOURNAL OF BONE AND MINERAL RESEARCH, Issue 1 2002Robert L. Perlot Jr. Abstract This investigation was based on the assumption that arg-gly-asp (RGD)-containing peptides are released from the extracellular matrix of bone and cartilage during the remodeling cycle. We asked the question: Can RGD peptides influence skeletal cell viability? Primary human osteoblasts, mouse MC-3T3-E1 cells, and chick chondrocytes were incubated with purified RGD-containing peptides and cell viability was determined. The RGD peptide did not kill osteoblasts, chondrocytes, or MC-3T3-E1 cells. In contrast, RGDS and GRGDSP peptides killed all three cell types. Osteoblast death was quite rapid, occurring within 6 h of treatment. transferase uridyl mediated nick end labeling (TUNEL) and transmission electron microscopy (TEM) analysis indicated that death was mediated by apoptosis. To learn if mitochondria transduced the death signal, cells were treated with RGDS and organelle function was evaluated using a voltage-sensitive fluorescent probe. It was observed that there was no net loss of fluorescence and, hence, it was concluded that mitochondria were not the primary effectors of the apoptotic response. Experiments were performed with enzyme inhibitors to determine the import of the caspase pathway on RGDS-mediated osteoblast apoptosis. Results of these studies, as well as a study conducted using a fluorescent substrate, pointed to caspase 3 mediating the effector stage of the apoptotic process. Finally, using a purified labeled-RGDS peptide, we showed that the molecule was not restricted by the plasma membrane because it was accumulated in the cytosolic compartment. Results of the investigation support the view that resorption of the extracellular matrix generates peptide products that can induce apoptosis of vicinal cells. [source] Long distance migration and marine habitation in the tropical Asian catfish, Pangasius krempfiJOURNAL OF FISH BIOLOGY, Issue 3 2007Z. Hogan A synthesis of catch data from southern Laos and life-history information indicate that adult Pangasius krempfi, an important Asian catfish, migrates up the Mekong River from the South China Sea in Vietnam past Cambodia, arriving in southern Laos each year in May. Strontium concentrations in the otoliths of river-caught P. krempfi are, on average, three to four times higher than the levels of strontium in the otoliths of related freshwater species, indicating marine and estuary habitation for fish caught in southern Laos. Pangasius krempfi muscle tissue samples from the same fish also exhibit stable isotope (,15N and ,13C) values characteristic of marine environments. The results of this investigation support the conclusion that P. krempfi is anadromous, spending a part of its life at sea and in the brackish water of the Mekong Delta before returning to spawn in fresh water. The fish travels at least 720 km to the Khone Falls in southern Laos, and possibly further. Spawning probably occurs in fresh water from June to August at which time young fish move down the Mekong River to the Mekong Delta. The data answer a previously unresolved question (the long-distance migratory behaviour of P. krempfi) and have important implications for the management and conservation of Mekong River fishes. [source] Communication skills in blind children: a preliminary investigationCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 1 2007D. M. James Abstract Background, There are anecdotal reports that blind children sometimes use language inappropriately, but there has been no recent systematic investigation of the communication skills of children with congenital blindness. The aim of the present study was to conduct a preliminary investigation of the communication skills of a group of children with congenital blindness. Methods, The parents of eight congenitally blind children completed the Children's Communication Checklist-2. Results, The checklist ratings showed that the communication profiles of a large proportion of the group warranted clinical investigation or were indicative of a communication disorder. Conclusions, The results from this preliminary investigation support the need for a larger study on the communication skills of children with congenital blindness. [source] Smoking, periodontal disease and the role of the dental professionINTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 2 2004KK Hilgers Abstract:, Epidemiological investigations support a firm relationship between smoking and periodontal disease. The likely benefits of smoking cessation programmes are considerable for periodontal disease, cancers and nearly all chronic systemic diseases. The mechanisms by which smoking may influence the development and progression of periodontal disease are as yet unclear, but may include changes in the vasculature, the immune and inflammatory systems, tissue oxygenation and the healing processes. Unfortunately, although dental professionals have more opportunities to encourage smokers to quit (most people visit their dentist more frequently than their doctor), dentists claim that they are not well informed on this subject. The purpose of this review is to describe the evidence for a link between smoking and periodontal disease, the possible pathology induced by smoking on the periodontal tissues and its impact on therapy, and to outline the smoking cessation techniques that are currently available. [source] Validity of species status of the parasitic mite Otodectes cynotisMEDICAL AND VETERINARY ENTOMOLOGY, Issue 2 2002J. Lohse Abstract A combined molecular and phenotypic approach was used to determine whether ear mites of the genus Otodectes (Acari: Psoroptidae) belong to a single species. The second internal transcribed spacer (ITS 2) of the rDNA of 16 isolates from 11 cats, two dogs, one arctic fox and two ferrets originating from four different continents was characterized. In addition, mites from dog, cat and arctic fox were investigated morphologically. Sequence comparisons revealed five different, but closely related genotypes which did not segregate according to host species or geographical origin. Morphologically, mites of the three host species did not differ significantly in their body or leg sizes. These investigations support the view that ear mites of the genus Otodectes from different hosts and geographical origins belong to a single species, Otodectes cynotis (Hering). [source] | ||||||||||