Comparison of Aminoglycoside Antibiotics and Cobalt Chloride for Ablation of the Lateral Line System in Giant Danios.

The mechanoreceptive lateral line system in fish is composed of neuromasts containing hair cells, which can be temporarily ablated by aminoglycoside antibiotics and heavy metal ions. These chemicals have been used for some time in studies exploring the functional role of the lateral line system in many fish species. However, little information on the relative effectiveness and rate of action of these chemicals for ablation is available. In particular, aminoglycoside antibiotics are thought to affect canal neuromasts, which sit in bony or trunk canals, differently from superficial neuromasts, which sit directly on the skin. This assumed ablation pattern has not been fully quantified for commonly used lateral line ablation agents. This study provides a detailed characterization of the effects of two aminoglycoside antibiotics, streptomycin sulfate and neomycin sulfate, and a heavy metal salt, cobalt (II) chloride hexahydrate (CoCl2), on the ablation of hair cells in canal and superficial neuromasts in the giant danio (Devario aequipinnatus) lateral line system, as a model for adult teleost fishes. We also quantified the regeneration of hair cells after ablation using CoCl2 and gentamycin sulfate to verify the time course to full recovery, and whether the ablation method affects the recovery time. Using a fluorescence stain, 4-Di-2-ASP, we verified the effectiveness of each chemical by counting the number of fluorescing canal and superficial neuromasts present throughout the time course of ablation and regeneration of hair cells. We found that streptomycin and neomycin were comparably effective at ablating all neuromasts in less than 12 h using a 250 µM dosage and in less than 8 h using a 500 µM dosage. The 500 µM dosage of either streptomycin or neomycin can ablate hair cells in superficial neuromasts within 2-4 h, while leaving those in canal neuromasts mostly intact. CoCl2 (0.1 mM) worked the fastest, ablating all of the hair cells in less than 6 h. Complete regeneration of the neuromasts in the lateral line system took 7 days regardless of chemicals used to ablate the hair cells. This study adds to the growing knowledge in hearing research about how effective specific chemicals are at ablating hair cells in the acoustic system of vertebrates.

El sistema de la línea lateral mecanorreceptora en los peces está compuesto de neuromastos que contienen células ciliadas, que pueden ser ablacionadas temporalmente con antibióticos aminoglucósidos e iones de metales pesados. Estos productos químicos se han utilizado durante algún tiempo en estudios que exploran el papel funcional del sistema de línea lateral en muchas especies de peces. Sin embargo, se dispone de poca información sobre la eficacia relativa y la tasa de acción de estos productos químicos para la ablación. En particular, se cree que los antibióticos aminoglucósidos afectan a los neuromastos de canal, que están posicionados en los canales de hueso o del tronco, de manera diferente a los neuromastos superficiales, que están posicionados directamente sobre la piel. Este supuesto patrón de ablación no se ha cuantificado por completo para los agentes de ablación de la línea lateral de uso común. Este estudio proporciona una caracterización detallada de los efectos de dos antibióticos aminoglucósidos, sulfato de estreptomicina y sulfato de neomicina, y una sal de metal pesado, hexahidrato de cloruro de cobalto (II) (CoCl2), en la ablación de las células ciliadas en neuromastos superficiales y de canal en el sistema de línea lateral en el danio gigante (Devario aequipinnatus), como un modelo para peces teleósteos adultos. También cuantificamos la regeneración de las células ciliadas después de la ablación con CoCl2 y sulfato de gentamicina para verificar el curso del tiempo hasta la recuperación completa y si el método de ablación afecta el tiempo de recuperación. Usando una tinción de fluorescencia, 4-Di-2-ASP, verificamos la efectividad de cada químico contando el número de fluorescentes neuromastos superficialises y de canal presentes a lo largo del tiempo de ablación y regeneración de las células ciliadas. Encontramos que la estreptomicina y la neomicina fueron comparablemente efectivas en la ablación de todos los neuromastos en menos de 12 horas usando una dosis de 250 µM y en menos de 8 horas usando una dosis de 500 µM. La dosis de 500 µM de estreptomicina o neomicina puede eliminar las células ciliadas en los neuromastos superficiales dentro de 2 a 4 horas, dejando las celulas de los neuromastos de canal casi intactas. CoCl2 (0,1 mM) funcionó más rápido, eliminando todas las células ciliadas en menos de 6 horas. La regeneración completa de los neuromastos en el sistema de la línea lateral tomó siete días, independientemente de los productos químicos utilizados para extirpar las células ciliadas. Este estudio se suma al creciente conocimiento en la investigación auditiva sobre cuán efectivos son los químicos específicos para eliminar las células ciliadas en el sistema acústico de los vertebrados.

Health care risk factors among women and personal behaviours among men explain the high prevalence of hepatitis C virus infection in Karachi, Pakistan.

To estimate the prevalence and identify factors associated with hepatitis C virus (HCV) infection among men and women in Karachi, Pakistan. We conducted a cross-sectional study of adult men and women in a peri-urban community of Karachi (Jam Kandah). Households were selected through systematic sampling from within all villages in the study area. All available adults within each household were interviewed about potential HCV risk factors. A blood specimen was collected to test for anti-HCV antibodies by enzyme immunoassay. We used generalized estimating equations while accounting for correlation of responses within villages to identify the factors associated with HCV infection. Of 1997 participants, 476 (23.8%) were anti-HCV positive. Overall, HCV infection was significantly associated with increasing age, ethnicity, and having received > or =2 blood transfusions, > or =3 hospitalizations, dental treatment and >5 injections among women. Among women, > or =2 blood transfusions [adjusted odds ratio (aOR) = 2.32], >5 injections during the past 6 months (aORs = 1.47), dental treatment (aOR = 1.31) and increasing age(aOR = 1.49), while among men, extramarital sexual intercourse (aOR = 2.77), at least once a week shave from barber (aOR = 5.04), > or =3 hospitalizations (aOR = 2.50) and increasing age (aOR = 1.28) were associated with HCV infection. A very high prevalence of HCV was found in the study population. Among women, unsafe health care practices, while among men extramarital sex, shaving from a barber and hospitalizations were associated with HCV infection. Efforts are needed to improve the safety of medical procedures to reduce the transmission of HCV in Pakistan [Corrections made in Summary after initial online publication.].

Morning report: a forum for reporting adverse drug reactions.

BACKGROUND: Most hospitals that monitor adverse drug reactions (ADRs) through reporting by nurses, pharmacists, medical record technicians, and quality improvement staff experience low rates of reporting. In teaching hospitals, inadequate orientation about the hospital activities, frequent changes in rotations between hospitals, and time commitments to educational pursuits may all undermine house staff's ability to perform ADR monitoring. The authors describe their experience since 1989 at the Department of Veterans Affairs Medical Center in Amarillo, Texas, in the use of verbal ADR reporting by physicians (mostly house staff) during the morning report in the medical service. ADR MONITORING PROGRAM: The morning report begins with a discussion of adverse outcomes of medications, usually from the previous 24 hours. The staff physicians use the opportunity to address the nature of the ADRs and the clinical circumstances leading up to them. Some ADR episodes require further peer review by a physician before being forwarded to the Pharmacy and Therapeutics Committee. EFFECT OF THE PROGRAM: Since the start of the ADR monitoring program in 1989, the number of self-reported ADRs in the medical service has increased over historical controls, even though no special training was given to house staff to detect ADRs. The surgical and psychiatric services, which did not hold morning reports, did not experience the same increase in ADR reports. CONCLUSIONS: The ADR monitoring program is notable for the simplicity of the reporting mechanism, the integration of the reporting into the regular work flow activities, the concurrent nature of the reporting, the educational opportunities, and the potential benefit for quality improvement of patient care.