Introduction: noise is one of the elements that defines the everyday environment at workplaces, it is the risk factor with the greatest impact on the working population. Objective: to evaluate the level of noise exposure in the Sanitary Hygienic Material Factory of Sancti Spíritus. Methodology: a descriptive study was made in 23 workplaces of the factory and measurements of noise exposure were performed in the month of October 2011, according to the methodology set out in the Cuban Standard (CS 19-01-14/83), for this purpose a Class 2 integrating sound level meter was used. Results: it was determined that the Equivalent Continuous Level (Leq.) of noise for 8 hours of work is higher than 85 dB(A) which is established in the CS 871/11 Safety and health at work. It was established that the rubber and miller are the workplaces reaching levels above 90 decibels noise. Conclusions: 100 % of the workers are exposed to noise levels above what is established by the current legislation in Cuba and work more than 8 hours daily, due to these reasons this factory is considered to be dangerous for its workers.

Introducción: el ruido es uno de los elementos que define el entorno cotidiano en el ámbito laboral, es el factor de riesgo con mayor incidencia en la población trabajadora. Objetivo: evaluar el nivel de exposición al ruido en la Fábrica de Materiales Higiénico Sanitarios de Sancti Spíritus. Metodología: se realizó un estudio descriptivo en el que se evaluaron 23 puestos de trabajo en la fábrica y se realizaron mediciones de exposición al ruido en el mes de octubre de 2011, según la metodología establecida en la norma cubana ( NC 19-01-14/83), para ello se utilizó un sonómetro integrador Clase 2. Resultados: se determinó que el Nivel Equivalente Continuo (Leq.) de ruido para 8 horas de trabajo es superior a los 85 dB(A) que es lo establecido en la NC 871/11 de Seguridad y salud en el trabajo. S e pudo establecer que el gomero y el molino son los puestos de trabajo que alcanzan niveles de ruido superiores a 90 decibeles. Conclusiones: el 100 % de los trabajadores están expuestos a niveles de ruido por encima de lo que establece la legislación vigente en Cuba y trabajan más de 8 horas diarias, por lo que se considera que esta fábrica constituye un centro riesgoso para la salud de sus trabajadores.

Las células de Schwann (CS) son la glía de sistema nervio periférico. El diseño de prótesis nerviosas se ha centrado en la producción de CS autólogas cultivadas a partir de nervios ciáticos (NC) y de ganglios de la raíz dorsal (GRD). Muy poca literatura reporta cultivo de células perineurales (CP) y fibroblastos endoneurales (FE), y no son consideradas como elementos a incluir en una prótesis. En este trabajo, se describe la importancia de la microdisección del nervio ciático y de los GRD para obtener cultivos de CS, FE y CP con 98%±2 de purificación. Las CS crecen sobre diferentes soportes, con y sin mitógenos. Se obtuvo un porcentaje de CS elevado cuando se elimina el epineuro y perineuro de los NC 90%±3 y la cápsula de los GRD 94%±3 antes de la disociación enzimática, comparado a 70%±4,2 sin microdisección u 80%±3,5 sin epineuro. Los FE se adhieren preferencialmente en las primeras 24 h y 20% de suero favorece su crecimiento. En el primer sub-cultivo, son 99% CS o FE, siendo confluentes a los 6 y 8 días respectivamente. Las CP o de la cápsula de GRD no se disocian y no crecen en sub-cultivos, únicamente crecen a partir de explantes de perineuro; no forman monocapa sino una "lámina" de múltiples capas celulares. En conclusión, la microdisección del GRD y del NC y su disociación son indispensables para obtener en pocos días CS, FE y CP de animales adultos en cultivos altamente purificados.

The Schwann cells (SC) are glial of system peripheral nerve. The nervous prostheses are related to the production of autologous SC obtained from the peripheral nervous and from the dorsal root ganglia (DRG). There is a small amount of literature that reports perineural cells (PC) and endoneural fibroblast (EF) cultures as elements to take account of prostheses. In this work, the micro dissection importance is described in the sciatic nerve (SN) and in the DRG to achieve SC, EF and PC culture with a purity of 98%. The SC grows up on different supports with and without mitogens. An elevated percentage of SC was obtained when the epineurium and the perineurium were removed in the SN (90%±3) and in the GRD (94%±3) before the enzymatic dissociation compared to seventy percentage when the micro dissection was omitted or eighty percentage without the epineurium micro dissection. The EF was adhered in the first twenty four hours and the twenty percentage of serum improved their growth. In the first passage, there is 99 percentage SC or EF, and they get the confluence in the six and eight day, respectively. The PC or the cells of the DRG don´t have neither a good dissociation, nor a growth in subcultures, they only grow from the perineurium explants that forms a lamina of several cellular layers more than a monolayer. In conclusion, the DRG and SN micro dissection and dissociated are indispensable to acquire in few days SC, EF and PC cultures with a high purity from adult animals.

Plasmid and chromosomal genes encode determinants of virulence for Yersinia pestis, the causative agent of plague. However, in vitro, Y. pestis genome is very plastic and several changes have been described. To evaluate the alterations in the plasmid content of the cultures in vitro and the impact of the alterations to their pathogenicity, three Y. pestis isolates were submitted to serial subculture, analysis of the plasmid content, and testing for the presence of characteristic genes in each plasmid of colonies selected after subculture. Different results were obtained with each strain. The plasmid content of one of them was shown to be stable; no apparent alteration was produced through 32 subcultures. In the other two strains, several alterations were observed. LD50 in mice of the parental strains and the derived cultures with different plasmid content were compared. No changes in the virulence plasmid content could be specifically correlated with changes in the LD50.

O objetivo deste trabalho foi avaliar a produção e composição do leite de vacas de corte das raças Charolês (C), Nelore (N), mestiças CN filhas de touros C e mestiças NC filhas de touros N, mantidas em pastagem nativa e submetidas a diferentes manejos no pré-desmame: suplementadas com farelo de arroz integral (0,7% do peso vivo) e que desmamaram aos 42 ou 63 dias pós-parto, ou não suplementadas e que desmamaram aos 63 dias. A idade das vacas variou de 3 a 12 anos, sendo agrupadas em quatro classes: primíparas, jovens, adultas e velhas. Os dados foram submetidos à análise de variância, cujo modelo estatístico incluiu os efeitos de manejo, grupo genético e idade da vaca, período e as interações entre esses fatores. Os teores de lactose e gordura não foram influenciados pelos fatores estudados. Houve interação significativa entre idade da vaca e período para a produção de leite e entre manejo e idade da vaca para o teor de proteína. Vacas suplementadas apresentaram maior produção de leite (3,85 contra 3,25 L/dia), teor de extrato seco total - EST (12,18 contra 11,83%) e teor de extrato seco desengordurado - ESD (8,75 contra 8,57%). A produção de leite decresceu com o avanço do período de lactação, sendo a queda mais acentuada nas vacas não suplementadas. Vacas CN produziram mais leite (4,17 L/dia) do que as puras, não diferindo das NC (3,76 L/dia). Vacas N apresentaram produção de leite similar (3,76 L/dia) às C (3,11 L/dia). No entanto, as primeiras apresentaram leite com melhor qualidade, incluindo proteína (3,16 contra 2,86%), EST (12,52 contra 11,46%) e ESD (8,87 contra 8,49%). Vacas adultas apresentaram maior teor de ESD, seguidas das vacas jovens, das primíparas e das velhas, com valores de 8,86; 8,62; 8,62; e 8,54%, respectivamente.

The objective of this work was to evaluate the production and composition of milk of beef cows of four genetic groups, including Charolais (C), Nellore (N), CN crossbreds daughters of C bulls, and NC crossbreds, daughters of N bulls, maintained on native pasture and submitted to different managements during pre-weaning: supplemented with rice bran (.7% of the body weight) and weaned at 42 or 63 days postpartum, or non supplemented and weaned at 63 days. The cow age varied from 3 to 12 years, being classified as: first calf, young, adult and old cows. The data were submitted to variance analysis, the statistic model included management, cow genetic group, cow age and period effects and the interactions among these factors. Lactose and fat contents were not influenced by the factors studied. There was a significant interaction between cow age and period for milk production and between management and cow age for protein content. Supplemented cows showed higher milk production (3.85 vs 3.25 L/day), total dry extract content - EST (12.18 vs 11.83%) and nonfat dry extract content - ESD (8.75 vs 8.57%). The milk production declined as the lactation period advanced, and the reduction was more accentuated in the non supplemented cows. CN crossbred cows produced more milk (4.17 L/day) than the straigthbreds, not differing from the NC crossbred (3.76 L/day). N cows showed milk production similar to the C cows, respectively, 3.16 and 3.11 L/day. However, N cows milk was of better quality, including protein (3.16 vs 2.86%), EST (12.52 vs 11.46%) and ESD (8.87 vs 8.49%). Adult cows showed higher ESD content, followed by the young cows, first calf and old cows, being 8.86; 8.62; 8.62 and 8.54%, respectively.