An electrostatic and probabilistic simulation model to describe neurosecretion at the synaptic scale.

A hybrid simulation model (macro-molecular dynamics and Monte Carlo method) is proposed to reproduce neurosecretion and exocytosis. A theory has been developed for vesicular dynamics based on quasi-static electric interactions and a simple transition-state model for the vesicular fusion. Under the non-equilibrium electric conditions in an electrolytic fluid, it is considered that the motion of each synaptic vesicle is influenced by electrostatic forces exerted by the membranes of the synaptic bouton, other vesicles, the intracellular and intravesicular fluids, and external elements to the neuron. In addition, friction between each vesicle and its surrounding intracellular fluid is included in the theory, resulting in a drift type movement. To validate the vesicle equations of motion, a molecular dynamics method has been implemented, where the synaptic pool was replaced by a straight angle parallelepiped, the vesicles were represented by spheres and the fusion between each vesicle and the presynaptic membrane was simulated by a Monte Carlo type probabilistic change of state. Density profiles showing clusters of preferential activity as well as fusion distributions similar to the Poisson distributions associated with miniature end-plate potentials were obtained in the simulations.

Prevalence of human papillomavirus, Chlamydia trachomatis, and Trichomonas vaginalis infections in Amazonian women with normal and abnormal cytology.

Sexually transmitted infections are an important cause of morbidity among sexually active women worldwide, and have been implicated as cofactors in the pathogenesis of cervical cancer. We investigated the prevalence of human papillomavirus (HPV), Chlamydia trachomatis (CT), and Trichomonas vaginalis (TV), and accessed the diversity of HPV in women with normal and abnormal cytology in Manaus, Brazil. We used polymerase chain reaction and HPV genotyping by direct sequencing. The chi-square test was used to calculate the absolute and relative frequencies of the categorical variables, and Fisher's test was used when P < 0.05. The level of significance was set at 5%. All statistical analyses were performed using R 2.9.0. There were statistically significant differences in age (P = 0.0395), education level (P = 0.0131), sexual partners (P = 0.0211), condom use (P = 0.0039), marital status (P < 0.0001), and pregnancy (P = 0.0003) between the normal and abnormal groups. HPV DNA was found in 36.56 and 93.88% of subjects in the normal and abnormal groups, respectively. A total of 19 genotypes were detected; HPV16 was the most common, followed by HPV58. The percentages of TV and CT DNA were 18.04 and 9.02% in the normal group, respectively. The percentages of HPV/TV and HPV/CT coinfection were 12.5% each in women with normal cytology. These findings improve our understanding of HPV, CT, and TV, and the distribution of HPV types, which may be relevant to vaccination strategies for protecting women from the north of Brazil from cervical cancers and precancerous lesions.

Mechanisms of epithelial fusion and repair.

One of the principal functions of any epithelium in the embryonic or adult organism is to act as a self-sealing barrier layer. From the earliest stages of development, embryonic epithelia are required to close naturally occurring holes and to fuse wherever two free edges are brought together, and at the simplest level that is precisely what the epidermis must do to repair itself wherever it is damaged. Parallels can be drawn between the artificially triggered epithelial movements of wound repair and the naturally occurring epithelial movements that shape the embryo during morphogenesis. Recent in vitro and in vivo wound-healing studies and analysis of paradigm morphogenetic movements in genetically tractable embryos, like those of Drosophila and Caenorhabditis elegans, have begun to identify both the signals that initiate these movements and the cytoskeletal machinery that drives motility. We are also gaining insight into the nature of the brakes and stop signals, and the mechanisms by which the confronting epithelial sheets knit together to form a seam.

Morphogenesis: unravelling the cell biology of hole closure.

Recent studies show that the underlying amnioserosa works actively to help bring together the two epithelial sheets and close the embryonic hole during dorsal closure in fruitfly development.

Dynamic actin-based epithelial adhesion and cell matching during Drosophila dorsal closure.

BACKGROUND: The adhesion of two epithelial sheets is a fundamental process that occurs throughout embryogenesis and during wound repair. Sealing of the dorsal epidermis along the midline of the Drosophila embryo provides a genetically tractable model to analyse the closure of such holes. Several studies indicate that the actin cytoskeleton plays a critical role in dorsal closure. Although many components of the signalling cascade directing this process have been identified, the precise cell-biological events upon which these signals act remain poorly described. RESULTS: By confocal imaging of living fly embryos expressing green fluorescent protein (GFP)-tagged actin, we found that dorsal closure relies on the activity of dynamic filopodia and lamellipodia that extend from front-row cells to actively zipper the epithelial sheets together. As these epithelial fronts approach one another, we observed long, thin filopodia, apparently 'sampling' cells on the opposing face. When the assembly of these actin-based protrusions was blocked (by interfering with the activities of Cdc42 and Jun N-terminal kinase signalling), the adhesion and fusion of opposing epithelial cells was prevented and their ability to 'sense' correct partners was also blocked, leading to segment misalignment along the midline seam. CONCLUSIONS: Dynamic, actin-based protrusions (filopodia and lamellae) are critical, both in the mechanics of epithelial adhesion during dorsal closure and in the correct 'matching' of opposing cells along the fusion seam.

Secretion of the amino-terminal fragment of the hedgehog protein is necessary and sufficient for hedgehog signalling in Drosophila.

BACKGROUND: The Drosophila segment polarity gene hedgehog encodes a member of a family of secreted proteins that are involved in a variety of patterning processes, in both vertebrates and invertebrates. Some of these processes depend upon short-range or contact-dependent interactions, whereas others seem to involve long-range signalling. Two different models have been proposed to account for the execution of these contrasting processes by the same proteins: one postulates that Hedgehog acts exclusively over short distances, its long-range influences being effected through regulation of other signalling factors; the second postulates that different aspects of Hedgehog activity are mediated by distinct forms of the protein that are generated by autoproteolysis. RESULTS: We have investigated these models by mutating the hedgehog coding region such that only the amino-terminal or carboxy-terminal half of the protein is secreted. Deletion of the carboxy-terminal portion has little effect on the signalling activity of the protein, whereas abolishing the secretion of the amino-terminal half leads to a complete loss of signalling. In addition, we find that increases in the level of expression within the normal hedgehog transcriptional domain of either the wild-type protein or the carboxy-terminal-deleted form expand the range of activity to a limited extent, but have only minor effects on cell identity. CONCLUSIONS: In Drosophila, all of the signalling activity of Hedgehog resides in the amino-terminal portion of the protein, the secretion of which is essential for its function. The range of Hedgehog is limited by the close association of the amino-terminal peptide with the cell surface but can be extended by elevating the level of its expression.

Cloning and characterization of two ubiquitin::79-amino-acid extension protein-encoding fusion genes from Lupinus albus.

Two different ubiquitin::79-amino-acid (aa) extension protein-encoding fusion genes were isolated from a Lupinus albus nuclear DNA library and sequenced. Both genes have 465-nucleotide open reading frames encoding a single ubiquitin (Ub) monomer fused in frame to a 79-aa extension (Ext) protein. The deduced aa sequences of the encoded Ub are identical to the aa sequences of Ub from other plants. The encoded Ext proteins are putative ribosomal proteins, highly basic, differing by 2 aa from each other, and have a high degree of similarity to Ext proteins from other plants.

Whole blood manganese concentrations in dogs with primary hepatitis.

OBJECTIVES: Increased whole blood manganese concentrations have been reported in humans with primary liver disease. Due to the neurotoxic effects of manganese, altered manganese homeostasis has been linked to the development of hepatic encephalopathy. Whole blood manganese concentrations are increased in cases of canine congenital portosystemic shunts, but it remains unclear whether dogs with primary hepatopathies also have altered manganese homeostasis. METHODS: Whole blood manganese concentrations were measured by graphite furnace atomic absorption spectrometry in 21 dogs with primary hepatitis, 65 dogs with a congenital portosystemic shunt, 31 dogs with non-hepatic illnesses and 18 healthy dogs. RESULTS: The whole blood manganese concentrations were significantly different between dogs with primary hepatitis, dogs with non-hepatic illnesses and healthy dogs (P=0·002). Dogs with primary hepatitis had significantly increased whole blood manganese concentrations compared with healthy dogs (P<0·05) and dogs with non-hepatic illnesses (P<0·01). Dogs with primary hepatitis had significantly lower whole blood manganese concentration compared with dogs with congenital portosystemic shunts (P=0·0005). CLINICAL SIGNIFICANCE: Dogs with primary hepatopathies have increased concentrations of whole blood manganese although these concentrations are not as high as those in dogs with congenital portosystemic shunts. The role of altered manganese homeostasis in canine hepatic encephalopathy is worthy of further study.

Urine concentrations of xanthine, hypoxanthine and uric acid in UK Cavalier King Charles spaniels.

OBJECTIVES: Xanthine urolithiasis and asymptomatic xanthinuria have been diagnosed in Cavalier King Charles spaniel dogs suggesting that primary xanthinuria may be a breed-related disorder, although its prevalence remains unclear. The hypothesis of this study was that asymptomatic xanthinuria is common in Cavalier King Charles spaniel dogs. METHODS: Free catch urine samples were collected from 35 client-owned Cavalier King Charles spaniel dogs and from 24 dogs of other breeds. The purine metabolites were measured by high-performance liquid chromatography. The urine ratios of xanthine/creatinine and hypoxanthine/creatinine were calculated and compared between the two groups of dogs. RESULTS: The urine concentrations of purine metabolites were not significantly different between the two groups and were very low in both. The urine concentrations of xanthine in all 35 Cavalier King Charles spaniel were markedly lower than in the previously reported case of xanthine urolithiasis in a UK Cavalier King Charles spaniel dog. CLINICAL SIGNIFICANCE: Asymptomatic xanthinuria was not detected in this UK Cavalier King Charles spaniel population. This data may be used as a reference for urinary purine metabolite concentrations in the dog.

JuRoLap: A resilient and economical home-made specimen retrieval bag

OBJECTIVE@#Specimen retrieval bags were used to remove cysts and masses in minimally invasiveurologic surgeries for more than 3 decades. This study aims to describe the steps in making a home-made specimen retrieval bag named JuRoLap and its safety and resiliency.@*MATERIALS AND METHODS@#The bag’s name was taken from the initials of the institution combined withthe department's short-name (uro) and laparoscopy (Lap). The bag is composed of a non-toxicpolyvinyl chloride (PVC) urine bag custom fitted according to the expected specimen size. The sideswere sealed using an impulse sealer leaving one side open. The bag ways rolled and introducedintracorporeally via the 12mm port. It was opened followed by specimen placement using standardlaparoscopic instruments. Purse-string suture at the one-side opening was tightened and extractedthrough the umbilical port extending the incision as necessary.@*RESULTS@#JuRoLap was used in 33 cases removing various organs such as adrenals, kidney, ureter,bladder and prostate. It was easily prepared, safe, resilient and economical costing approximatelyUSD 0.68. It was essential to routinely check its durability by doing a leak test prior to sterilization.Proper rolling, transparent plastic component of the bag and the use of two laparoscopic graspersprovided ease in bag deployment and specimen entrapment. It was also observed that smaller incisionon extraction site as compared to the specimen size was needed due to the resiliency of the bag.Despite the required learning curve in organ entrapment and extraction, there were no complicationsand specimen leakage noted.@*CONCLUSION@#JuRoLap specimen retrieval bag is organ size specific, safe, resilient and low cost specimenretrieval bag innovation.

Transcriptional activation of hedgehog target genes in Drosophila is mediated directly by the cubitus interruptus protein, a member of the GLI family of zinc finger DNA-binding proteins.

Members of the Hedgehog (Hh) family of secreted proteins have been identified recently as key signaling molecules that regulate a variety of inductive interactions central to the development of both Drosophila and vertebrates. Despite their widespread importance, the way in which Hh signals are transduced inside the cell remains poorly understood. The best candidate for a transcription factor that mediates Hh signaling in Drosophila is the product of the cubitus interruptus (ci) gene, a zinc finger protein that exhibits significant homology to protein products of the vertebrate GLI gene family. Here, we show that elevated levels of Ci are sufficient to activate patched (ptc) and other hh target genes, even in the absence of hh activity. We also show that Ci can function as a transcriptional activator in yeast and demonstrate that the zinc finger domain of the protein is sufficient for its target specificity. Finally, we identify sequences in the promoter region of the ptc gene, a primary target of Hh signaling, that are identical to the consensus-binding sequence of the GLI protein and are required for reporter gene expression in response to Hh activity. Taken together, our results strongly support the role for Ci as the transcriptional activator that mediates hh signaling.

Fístulas enterocutáneas: tratamiento quirúrgico / Enterocutaneous fistulas: surgical treatment

Entre 1971 y 1986 se atendió en el Instituto Nacional de Pediatría a 55 niños con diagnóstico de fístulo enterocutánea; la edad de los sujetos iba de tres a 17 años. El 80% de los pacientes fueron enviados de otros hospitales para tratamiento. Los factores desencadenantes más frecuentes fueron: apendicitis perforada, perforación intestinal pos Salmonella, enfermedad isquémica intestinal, vólvulo por Ascaris e invaginación intestinal. En 38 enfermos se diagnóstico fístula de gasto alto y en 17, de gasto bajo. De los 55 pacientes, en 41 se dió tratamiento conservador con dieta elemental, alimentación parenteral, o ambas, y en 30 (73%) se logró cierre espontáneo. En los 14 restantes se requirió intervención quirúrgica y se logró el cierre en 12 (86%). La mortalidad fué de 25% por septisemia y sus complicaciones; los enfermos que murieron tenían fístulas de gasto alto

Frecuencia de infecciones nosocomiales: I.M.S.S. (Jalisco, 1979-1985) / Frecuency of nosocomiales infections: I.M.S.S. (Jalisco, 1979-1985)

Perfil epidemiológico de las infecciones nosocomiales ocurridas en el Hospital General Regional 46 del Instituto Mexicano del Seguro Social en Jalisco, de 1979 a 1985. En este sentido, se ha observado un índice muy bajo de 1.6 por 100 egresos, debido principalmente al subregistro efectuado por el sistema de vigilancia epidemiológica en lo relativo a infecciones y reducida estancia hospitalaria, así como a la escasa notificación del personal operativo. Tales acontecimientos se pueden modificar con un sistema que permita mayor atención y empleo del equipo de salud en el estudio de dichas enfermedades nosocomiales

Reflexiones sobre la organización de servicios de neonatología en el marco de la situación neonatal en el país / Reflections on neonatal services organization in the context of the situation in the country neonatal

El presente documento describe un modelo de organización de servicios neonatales por niveles de atención neonatal y se plantean los componentes en la atención integral del recién nacido en el marco de un sistema regionalizado y sistematizado de atención perinatal(AU)

Reflexiones sobre la organización de servicios de neonatología en el marco de la situación neonatal en el país / Reflections on neonatal services organization in the context of the situation in the country neonatal

El presente documento describe un modelo de organización de servicios neonatales por niveles de atención neonatal y se plantean los componentes en la atención integral del recién nacido en el marco de un sistema regionalizado y sistematizado de atención perinatal