Evidence for synergistic and complementary roles of Bassoon and darkness in organizing the ribbon synapse.

Ribbon synapses are tonically active high-throughput synapses. The performance of the ribbon synapse is accomplished by a specialization of the cytomatrix at the active zone (CAZ) referred to as the synaptic ribbon (SR). Progress in our understanding of the structure-function relationship at the ribbon synapse has come from observations that, in photoreceptors lacking a full-size scaffolding protein Bassoon (Bsn(ΔEx4/5)), dissociation of SRs coincides with perturbed signal transfer. The aim of the present study has been to elaborate the role of Bassoon as a structural organizer of the ribbon synapse and to differentiate it with regard to the ambient lighting conditions. The ultrastructure of retinal ribbon synapses has been compared between wild-type (Wt) and Bsn(ΔEx4/5) mice adapted to light (low activity) and darkness (high activity). The results obtained suggest that Bassoon and environmental illumination synergistically and complementarily act as organizers of the ribbon synapse. Thus, light-dependent and Bassoon-independent regulation involves initial SR tethering to the membrane and a basic shape transition of ribbon material from spherical to rod-like, since darkness induces these features in Bsn(ΔEx4/5) rod spherules. However, the tight anchorage of the SR via an arciform density and the proper assembly of SRs to the full-sized horseshoe-shaped complex depend on Bassoon, as these steps fail in Bsn(ΔEx4/5) rod spherules.

Classification of prosthetics used in hernia repair based on weight and biomaterial.

PURPOSE: The aim of this study was to classify the polymeric prosthetics used for hernia repair based on biomaterial composition and weight in an effort to clarify to surgeons what kinds of material they are dealing with and to provide a standardized system of categorization. MATERIALS AND METHODS: An intensive research effort was carried out on prosthetics that are commercially available worldwide. We conducted a search of the medical literature and companies' websites to find the weights and thicknesses of commercially available prosthetics. Where these data were lacking, we contacted manufacturers directly in order to render the research more complete. A total of 166 products were considered for classification based on biomaterial properties. Among these, a homogeneous group of 80 polypropylene monofilament knitted or woven prosthetics was selected for classification based on weight. Weights were provided for 70 prosthetics (87%), and both the weight and thickness was provided for 40 prosthetics (50%). RESULTS: Classification based on weight: Ultra-light <35 g/m(2), Light ≥35 < 70 g/m(2), Standard ≥70 < 140 g/m(2), Heavy ≥140 g/m(2). Classification based on biomaterial composition: simple (prosthetics made of one pure biomaterial); composite (prosthetics made of two or more different layers); combined (prosthetics made of two materials knitted or woven together); and biologic. CONCLUSION: Weight and biomaterial classifications were proposed after an extensive analysis of commercially available prosthetics. The need for a common terminology is important to avoid misunderstandings among clinicians and technicians.

Hydatidosis in the province of La Pampa, Argentina, 1998.

Echinococcus granulosus is the agent that causes the classical hydatidosis or cystic echinococcosis. The most spread cycle in South America is the sheep-dog cycle, and offers favorable conditions for the development of the parasite. As the province of La Pampa shows an endemic presence with notification of cases and infected dogs, the present work has the aim of contributing to the study of the distribution and prevalence of the disease in the district of Maracó, La Pampa, Argentina. Dogs of 36 farms that had ovines, were dosed with arecoline hydrobromide at a dose of 3.5 mg/kg. Dogs from 27 (75%) farms resulted positive to Tenia sp. and 3 (8.3%) to E. granulosus. Blood samples were taken to all the people living in all the inquired farm and were processed by the ELISA test for hydatidosis. A retrospective survey on cases of human hydatidosis attended in the Hospital of General Pico, head if the sanitary region, and in two private clinics was performed. Analysis of clinical records indicated 11 cases operated during the period 1996/1997 (annual incidence rate of 6.8 per 100,000 inhabitants). It is of public health interest to fulfill epidemiologic investigations in other districts of the Province of La Pampa with the aim of delimitating the endemic distribution within the province and also organizing surveillance systems on human hydatidosis.

[Hydatidosis/echinococcosis in General Acha, La Pampa Province, Argentina]. / Hidatidosis/equinococosis en el área de General Acha, Provincia de la Pampa, Argentina.

Hydatidosis situation in the General Acha area (La Pampa Province) is described herein. The work comprises a retrospective compilacion of new hydatidosis human cases, the findings in seroepidemiological surveys with enzyme immuno assay (EIA) for hydatidosis in human population, and investigation on dog Echinococcus granulosus infection prevalence carried out on the basis of arecoline bromhydrate application. Sixteen human cases were detected during 1994 (incidence rate: 26.7/100,000), founding a serological prevalence of 1.3%. Studies on dog echinococosis have shown a prevalence rate of 2.3%. The epidemiological situation of hydatidosis is analyzed by comparison with values from other endemic areas. These results suggest the necessity of completing surveys in the whole provincial territory, and the implementation of educational and sanitary measures aimed to controlling this zoonosis.

Low-dose heparin as an antithrombotic agent.

Heparin, after subcutaneous administration, has been found to be able to bind to endothelial receptors both in rabbits and in humans. N-sulphonate 35S-heparin remains bound in rabbits for at least 24 h and is able to enhance the inactivation process of thrombin and factor Xa. Heparin subcutaneously (200 U/kg) injected for 2 weeks resulted in an enhanced inactivation of thrombin and factor Xa by the endothelium. The antithrombin-enhancing activity persists longer than the anti-Xa activity. In man, daily subcutaneous administration of heparin (12,500 U/day) for 2 weeks significantly reduces the increased fibrinopeptide A plasma levels and normalizes the increased 125I-fibrinogen turnover. The present work indicates that heparin administration at a low dose represents a treatment able to remarkably enhance the antithrombotic properties of the vessel wall, independently of the presence of detectable heparin levels in the circulating blood.