Surface Morphology and Structural Modification Induced by Femtosecond Pulses in Hydrogenated Amorphous Silicon Films

This work investigates the modification, resulting from fs-laser irradiation (150 fs, 775 nm and 1 kHz), on the structure and surface morphology of hydrogenated amorphous silicon (a-Si:H) thin films. The sample morphology was studied by performing a statistical analyzes of atomic force microscopy images, using a specially developed software that identifies and characterizes the domains (spikes) produced by the laser irradiation. For a fluence of 3.1 MJ/m2, we observed formation of spikes with smaller average height distribution, centered at around 15 nm, while for fluencies higher than 3.7 MJ/m2 aggregation of the produced spikes dominates the sample morphology. On the other hand, Raman spectroscopy revealed that a higher crystalline fraction (73%) is obtained for higher fluences (> 3.1 MJ/m2), which is accompanied by a decrease in the size of the produced crystals. Therefore, such results indicate that there is a trade-off between the spike distribution, crystallization fraction and size of the nanocrystals attained by laser irradiation, which has to be taken into account when using such approach for the development of devices.

Effect of ischemic preconditioning on injuries caused by ischemia and reperfusion in rat intestine

To study whether ischemic preconditioning (IPC) attenuated intestinal dysfunction caused by ischemia (I) and reperfusion (R), rats were underwent 60 minutes of I which was produced by occlusion of the superior mesenteric artery, and/or 120 minutes R. The IPC group had the I procedure previously stimulated for 5 minutes and the R for 10 minutes. IPC and sham groups were injected with saline solution (SS) via the femoral vein 5 minutes before the I and R, and for R. After I or I/R, 2-cm jejunal segments were mounted in an organ bath to study neurogenic contractions stimulated by electrical pulses or KCl using a digital recording system. Thin jejunal slices were stained with hematoxylin and eosin for optical microscopy. Compared with the sham group, jejunal contractions were similar in the IPC + I and the IPC + I/R groups, but reduced in the I + SS and the I/R + SS groups. The jejunal enteric nerves were damaged in the I + SS and the I/R + SS groups, but not in the IPC groups. These results suggested that ischemic preconditioning attenuated intestinal dysfunction caused by I and I/R.

Phase I trial of DNA-hsp65 immunotherapy for advanced squamous cell carcinoma of the head and neck

Considering that mycobacterial heat-shock protein 65 (hsp65) gene transfer can elicit a profound antitumoral effect, this study aimed to establish the safety, maximum-tolerated dose (MTD) and preliminary efficacy of DNA-hsp65 immunotherapy in patients with advanced head and neck squamous cell carcinoma (HNSCC). For this purpose, 21 patients with unresectable and recurrent HNSCC were studied. Each patient received three ultrasound-guided injections at 21-day intervals of: 150, 600 or 400 microg of DNA-hsp65. Toxicity was graded according to CTCAE directions. Tumor volume was measured before and after treatment using computed tomography scan. The evaluation included tumor mass variation, delayed-type hypersensitivity response and spontaneous peripheral blood mononuclear cell proliferation before and after treatment. The MTD was 400 microg per dose. DNA-hsp65 immunotherapy was well tolerated with moderate pain, edema and infections as the most frequent adverse effects. None of the patients showed clinical or laboratory alterations compatible with autoimmune reactions. Partial response was observed in 4 out of 14 patients who completed treatment, 2 of which are still alive more than 3 years after the completion of the trial. Therefore, DNA-hsp65 immunotherapy is a feasible and safe approach at the dose of 400 microg per injection in patients with HNSCC refractory to standard treatment. Further studies in a larger number of patients are needed to confirm the efficacy of this novel strategy.

[Secular trends in respiratory diseases of childhood in the city of São Paulo, Brazil (1984-1996)]

OBJECTIVE

Data from two consecutive household surveys undertaken in mid-80s and mid-90s allow to characterize and analyse secular trends in infant and child respiratory diseases in the city of S. Paulo, Brazil.

METHODS

The two surveys included random population samples aged from zero to 59 months (1,016 in the period of 1984-85 and 1,280 in 1995-96). In both surveys the instant prevalence of high respiratory diseases (above the epiglottis) and low respiratory diseases with or without wheezing were calculated. All sampled children were examined in their household at a random day by trained pediatricians using standardized procedures. The examinations included medical history, past respiratory diseases and a complete physical examination. In both surveys the examinations were distributed throughout a period of almost 12 months to assure a uniform coverage of the various areas of the city along the four seasons of the year. For each survey, the study of the social distribution of the diseases took into account tertiles of the per capita family income. For the study of the determinants of secular trends, hierarchical causal models, multivariate regression analyses and calculations analogous to the ones used to assess population attributable risks were applied.

RESULTS/CONCLUSIONS

In the time span from the first to the second survey, there was a substantial increase in the prevalence of both low (from 22.2% to 38.8%) and high respiratory diseases (from 6.0% to 10.0% and from 0.8% to 2.8%, without and with wheezing, respectively). In the case of high respiratory disease and low respiratory disease without wheezing, an increase in prevalence was observed among all social strata, which did not interfere with the slightly less favourable situation of the lower income groups. In the case of low respiratory disease with wheezing, the increase was only observed among middle and low-income groups, being particularly high among the lower income group, yielding a significant inverse gradient between income and respiratory disease. Positive changes in distal (family income and maternal schooling) and in intermediate determinants related to housing characteristics would have resulted in a decline, not an increase, in the prevalence of respiratory diseases in the city. The duplication in the attendance rate to day care nurseries seen in the period could have counterbalanced the positive effect due to socioeconomic and housing variables but would not be enough to explain an increase in the disease.

Diagnosis and prognosis of wheezing disorders in young children in the city of São Paulo, Southeast Brazil

Three-hundred-and-ninety-seven children aged 2-59 mo presenting to the paediatric emergency departments of five public hospitals in São Paulo, Brazil, with an acute episode of lower respiratory disease were examined. The children were classified into the following diagnostic categories: acute bronchitis, acute bronchiolitis, pneumonia, asthma, post-bronchiolitis wheezing and wheezing of uncertain aetiology. Three years after the initial study, the homes of the children diagnosed as asthmatic or as having wheezing of uncertain aetiology were visited to collect information on subsequent episodes of lower respiratory disease. This paper reports the proportional incidence of different categories of lower respiratory disease and the results of an analysis to investigate clinical features that might distinguish wheezing children between those with asthma and those with an infectious disease. The predictions made for children with wheezing of uncertain aetiology were then compared with the follow-up data. Recurrent wheezing disorders (asthma, post-bronchiolitis wheezing) were common in the study sample (47% of children). Thirty-six percent of children with an initial diagnosis of wheezing of uncertain aetiology were diagnosed as asthmatic by another doctor over the next 3 y. We were unable to identify any clinical features that were useful in identifying those children likely to be diagnosed subsequently as asthmatic.

CONCLUSIONS

The use of a diagnostic category similar to that which we have called "wheezing of uncertain aetiology" might help to alert physicians early to the possibility of asthma without interfering in the management of the illness. Such a classification might also be useful in epidemiological investigations of the aetiology of lower respiratory diseases.

[Referred morbidity and the utilization of health services in Brazilian urban areas: methodology]

The reorganization of the Brazilian health system in the last few years has been based on the decentralization of the services and the integration of preventive and curative medicine, then creating new needs in term of the health information needed for health planning. The planning and administration of a regionalized and integrated health system calls for information about the population's morbidity profile, and the description of the pattern of the utilization of the health services, which can be obtained by means of household health surveys. The methodology utilized in a household health survey carried out in the Metropolitan Area of S. Paulo, Brazil, from July 1989 to June 1990, is described. This survey has some distinct methodological characteristics, such as the sampling process that defined the domains by age and sex, allowing an analysis of populational groups less well represented in the general population, as that of less than one year of age and that of aged people, as well as the use of the results of the latest Brazilian Census in 1991 for adjusting the sample.

Rubella seroepidemiology in a non-immunized population of São Paulo State, Brazil

A rubella serological survey of 476 individuals selected by cluster sampling technique from Caieiras, a small town located in the outskirts of São Paulo city, southeastern Brazil, was carried out over the period November 1990-January 1991. The aim of the study was to characterize rubella epidemiology in a representative non-immunized community in south east Brazil. The survey comprised a seroprevalence study, stratified by age (0-40 years) and a seroconversion study of rubella vaccine in non-infected children below 2 years of age. Mathematical techniques were applied to resultant data sets to determine the age dependent rates of decay in the proportion of individuals with maternally derived antibodies, vaccine seroconversion, and infection of susceptibles, termed the force of infection, and to estimate the average age at first infection.