Influenza A infections: predictors of disease severity

Influenza affects approximately 10% of the world's population annually. It is associated with high morbidity and mortality rates due to its propensity to progress to severe acute respiratory infection, leading to 10-40% of hospitalized patients needing intensive care. Characterizing the multifactorial predictors of poor prognosis is essential for developing strategies against this disease. This study aimed to identify predictors of disease severity in influenza A-infected (IFA-infected) patients and to propose a prognostic score. A retrospective cross-sectional study was conducted with 142 IFA-infected out- and inpatients treated at a tertiary hospital between 2010 and 2018. The viral subtypes, hemagglutinin mutations, viral load, IL-28B SNPs, and clinical risk factors were evaluated according to the patient's ICU admission. Multivariate analysis identified the following risk factors for disease severity: neuromuscular diseases (OR = 7.02; 95% CI = 1.18-41.75; p = 0.032), cardiovascular diseases (OR = 5.47; 95% CI = 1.96-15.27; p = 0.001), subtype (H1N1) pdm09 infection (OR = 2.29; 95% CI = 1.02-5.15; p = 0.046), and viral load (OR = 1.43; 95% CI = 1.09-1.88; p = 0.009). The prognosis score for ICU admission is based on these predictors of severity presented and ROC curve AUC = 0.812 (p < 0.0001). Our results identified viral and host predictors of disease severity in IFA-infected patients, yielding a prognostic score that had a high performance in predicting the IFA patients' ICU admission and better results than a viral load value alone. However, its implementation in health services needs to be validated in a broader population.

The association of breastfeeding and other factors on respiratory virus positivity and severity in hospitalized children

Acute respiratory infections (ARIs) are the most prevalent diseases in children under five years old, and viruses are the leading cause. ARIs arise due to numerous factors, including age, contact with siblings or other children in daycare centers, and environmental pollution. Breastfeeding reportedly confers protection against ARIs through bioactive components related to mucous epithelial immunity. This study aimed to evaluate the frequency and severity of viral ARIs in hospitalized children, together with the status and duration of exclusive breastfeeding (EBF) and other associated factors. It comprised an epidemiological surveillance study to investigate respiratory viruses in hospitalized children, in which demographic and clinical data were collected. Overall, 279 patients were included, 190 (68%) had positive viral results, and 132 (47%) were exclusively breastfed. In an adjusted analysis, it was observed that older children, parents' educational level, and the presence of chronic disease were significantly related to EBF for more than six months. No significant differences were observed in viral positivity and disease severity concerning EBF. Whereas EBF status was associated with the positive rate of virus detection, the significance did not remain after adjustment, and it was not considered a protective factor against ARIs. On the other hand, young age and exposure to tobacco were confirmed as risk factors of frequency and severity, respectively. Such confounding factors can impact the analysis and should be considered in future studies. This article is protected by copyright. All rights reserved.

Standardization of a high-performance RT-qPCR for viral load absolute quantification of influenza A

Influenza is an acute viral infectious respiratory disease worldwide, presenting in different clinical forms, from influenza-like illness (ILI) to severe acute respiratory infection (SARI). Although real-time quantitative polymerase chain reaction (qPCR) is already an important tool for both diagnosis and treatment monitoring of several viral infections, the correlation between the clinical aspects and the viral load of influenza is still unclear. This lack of clarity is primarily due to the low accuracy and reproducibility of the methodologies developed to quantify the influenza virus. Thus, this study aimed to develop and standardize a universal absolute quantification for influenza A by reverse transcription-quantitative PCR (RT-qPCR), using a plasmid DNA. The assay showed efficiency (Eff%) 98.6, determination coefficient (R₂⁾ 0.998, linear range 10^¹ to 10^¹⁰, limit of detection (LOD) 6.77, limit of quantification (LOQ) 20.52 copies/reaction. No inter and intra assay variability was shown, and neither was the matrix effect observed. Serial measurements of clinical samples collected at a 72h interval showed no change in viral load. By contrast, immunocompetent patients have a significantly lower viral load than immunosuppressed ones. Absolute quantification in clinical samples showed some predictors associated with increased viral load: (H1N1)pdm09 (0.045); women (p = 0.049) and asthmatics (p = 0.035). The high efficiency, precision, and previous performance in clinical samples suggest the assay can be used as an accurate universal viral load quantification of influenza A. Its applicability in predicting severity and response to antivirals needs to be evaluated.

Genetic progress estimation strategy for upright common bean plants using recurrent selection

Common bean producers in Brazil tend to grow plants as upright as possible. Because the control of this trait involves a large number of genes, recurrent selection (RS) is the best approach for successful plant improvement. Because plant architecture (PA) is evaluated using scores and usually has high heritability, RS for PA is performed through visual selection in generation S₀. The aim of the present study was to evaluate selection progress and investigate whether this progress varies with the number of selected progenies or the generation evaluated. In addition, the effect of RS for the upright (PA) trait on progeny grain yield (GY) was investigated. Data of progenies S_0:3 and S_0:4 of the fifth, eighth, and twelfth cycles were used. A combined analysis of variance was performed using the adjusted means of the 47 best progenies from each generation and cycle, using two control cultivars as reference. A joint analysis of the two generations used during the evaluation of progenies for the different cycles was also performed. The genetic progress (GP) was estimated by fitting a linear regression equation to the relationship between the adjusted mean of each cycle and the number of cycles. We found that RS was efficient and the estimated GP of the evaluated progenies was 4.5%. Based on the GY heritability estimates, in more advanced generation selection for GY can be successfully performed on progenies. Thus, the selection already done for PA in F₂ could be associated to the most productive progenies.

Traditional Periodization versus Optimum Training Load Applied to Soccer Players: Effects on Neuromuscular Abilities

It is unknown whether traditional periodization of strength-power training involving accumulation, transformation and realization blocks is superior to other simpler and more practical training schemes. The purpose of this study was thus to investigate changes in strength/power/speed characteristics of elite soccer players in response to either classic strength-power periodization (TSP) or optimum power load (OPL). 23 professional soccer players were randomly assigned to TSP or OPL for 6 weeks in-season regular training (3 times per week). TSP involved half squats or jump squats, depending on the respective training block, while OPL involved only jump squats at the optimum power load. Results revealed that both groups presented similar significant (P<0.05) improvements in squat one repetition maximum, squat and countermovement jump heights and change of direction speed. In addition, although both groups reported significant increases in sprinting speed (P<0.05); delta change scores demonstrated a superior effect of OPL to improve 10- and 20-m speed. Similarly, OPL presented greater delta change in mean propulsive power in the jump squat. Therefore, training continuously at the optimum power zone resulted in superior performance improvements compared to training under classic strength-power periodization.

Effects of far infrared rays emitting clothing on recovery after an intense plyometric exercise bout applied to elite soccer players: a randomized double-blind placebo-controlled trial

The aim was to investigate the effects of far infrared (FIR) ray emitting clothes on indirect markers of exercise-induced muscle damage and physical performance recovery after a plyometric bout applied to soccer players. Twenty-one male players (18.9±0.6 years; 70.8±5.01 kg; 178.3±0.06 cm) performed 100 drop-jumps. Six hours after the bout, athletes put on FIR clothes (FIR) (density of 225 g·m^-2, 88% far infrared rays emitting polyamide 66 Emana yarn (PA66) fibre, 12% Spandex, emissivity of 0.88 and power emitted of 341 W/m2µm at 37°C in the 5-20 µm wavelength range, patent WO 2009/077834 A2) (N = 10) or placebo clothes (PLA) (N = 11). Mid-thigh circumferences, creatine kinase (CK), and delayed-onset muscle soreness (DOMS) were assessed before, immediately after and 24, 48, and 72 h after the bout. Squat (SJ) and countermovement jump (CMJ) heights were measured before and at 24, 48, and 72 h after, while 1RM leg press (maximum strength) was measured before and at 72 h after the plyometrics. No differences between groups were found in mid-thigh circumferences, SJ, CMJ or 1RM. CK increased significantly 24 h after the plyometrics in comparison to before (p < 0.05) in both groups. PLA showed significant DOMS increases at 24, 48, and 72 h, while FIR showed significant increases at 24 and 48 h (p < 0.05). DOMS effect sizes were greater in FIR (moderate at 48 h, ES = 0.737 and large at 72 h, ES = 0.844), suggesting that FIR clothes may reduce perceived DOMS after an intense plyometric session performed by soccer players.

Multiple cutaneous lipomatous neurofibromas

Cutaneous lipomatous neurofibroma is a rare variant of neurofibroma with a little known pathogenesis; its presence has never been described in Brazil. A 61- year-old woman complaining scalp papules for one year, presented with skin colored to yellowish papules on the scalp. She noted that they were sometimes itchy and occasionally bled. Dermoscopy showed amorphous material, milky white, with a small poorly delimited yellowish area. Histopathological examination revealed spindle cell proliferation associated with mature adipocytes. Cutaneous lipomatous neurofibroma appears to be an underdiagnosed condition owing to the low index of suspicion and lack of knowledge of its existence. Few cases have been reported in the literature.

Effects of detraining on neuromuscular performance in a selected group of elite women pole-vaulters: a case study

AIM

to determine the effects of 28 days of inactivity on neuromuscular performance of elite women pole-vaulters.

METHODS

Four athletes undertook measurements of rate of force development (RFD), unloaded and loaded vertical jump tests, drop jumps and a 45 m sprint test before and after a transition period of planned inactivity.

RESULTS

The RFD and the ability to accelerate over very short distances (5 m) while sprinting improved after training cessation. Acceleration over longer distances (5-45 m) was impaired, while unloaded and loaded vertical jump tests suffered trivial to small changes.

CONCLUSIONS

Therefore, we conclude that detraining periods of approximately one month or even longer may be implemented in elite pole-vaulters without significantly impairing performance. In addition, given that some neuromechanical capacities are enhanced after training reduction, our results can help coaches to implement tapering strategies in order to induce neuromuscular improvements and/or to achieve peak performance.

Fatal Nocardia cyriacigeorgica spontaneous bacterial peritonitis

We report the first case of fatal spontaneous bacterial peritonitis and fulminant hepatitis caused by Nocardia cyriacigeorgica in a patient with hepatitis C-related liver cirrhosis.

Giant pseudoaneurysm of the left ventricular outflow tract: a rare disease

Pseudoaneurysm of the left ventricular outflow tract (LVOT) is a rare disease with high morbidity and mortality, resulting from left ventricular damage due to myocardial infarction, infective endocarditis or surgical trauma. A case of giant pseudoaneurysm of the LVOT, even more rarely reported in the literature, is described. The lesion was detected 12 years after aortic valve replacement for infective endocarditis in a young patient, a former intravenous drug user. As it is an uncommon disease, little is known about its clinical presentation and treatment.

Testing liver allocation in São Paulo, Brazil: the relationship of model for end-stage liver disease implementation with a reduction in waiting-list mortality

INTRODUCTION

In 2006, the model for end-stage liver disease (MELD) was launched as a new liver allocation system in Sao Paulo, Brazil. We designed this study to assess the results of the new allocation policy on waiting list mortality.

METHODS

We reviewed the state of Sao Paulo liver transplant database from July 2003 through July 2009. Patients were divided in those who were transplanted before (pre-MELD group) and those who were transplanted after (post-MELD group) the implementation of the MELD system. Included were adult liver transplant candidates. Waiting list mortality was the primary endpoint.

RESULTS

The unadjusted death rate in patients on the waiting list decreased significantly after the implementation of the MELD system (from 91.2 to 33.5/1000 patients/year, P < .0001). Multivariate analysis has shown a significant drop of the risk of waiting list death for post-MELD patients (odds ration 0.34, P < .0001).

CONCLUSION

There was a reduction in waiting time and list mortality after the implementation of the MELD system in Brazil. Patients listed in the post-MELD era had a significant reduction of death risk on the waiting list. Future studies should assess posttransplant outcomes.

Increasing the donor pool reduces the severity of liver disease: lessons learned from São Paulo, Brazil

INTRODUCTION

A new liver allocation system driven by the model for end-stage liver disease (MELD) score was implemented in Brazil in 2006. In association with the new allocation policy, there was a concomitant expansion of the number of donors. We designed this study to assess whether a potential expansion of the donor pool with these educational campaigns had reduced the severity of liver disease at transplantation.

METHODS

We retrospectively reviewed the state of São Paulo liver transplant database from July 2003 through July 2009. Patients were divided into groups: those who were transplanted before (pre-MELD group) and those who were transplanted after (post-MELD group) the implementation of the MELD system. The number of transplantations and the severity of liver disease were the endpoints of the study.

RESULTS

There has been a significant shift towards an older donor population, mainly those who are dying of cerebrovascular accidents. The average MELD score has changed over time. Approximately one quarter of the patients have been transplanted with a MELD score of more than 30 in the post-MELD era. However, this number has decreased over the past 3 years (P = .012). Currently, it has been possible to transplant patients with a MELD score from 25 to 30. The number of transplantations due to hepatocarcinoma (HCC) has increased 8-fold.

CONCLUSION

An aggressive educational campaign has successfully expanded the donor pool with a concomitant yearly reduction of the average MELD score at the time of transplantation. Patients with HCC have been benefited tremendously with the new allocation system.

Liver recipient survival rate before and after model for end-stage liver disease implementation and use of donor risk index

BACKGROUND

The progressive increase in the demand for liver transplantation has led to changes in donor selection and allocation, such as the Model for End-Stage Liver Disease Score (MELD). Characteristics related to the donor, recipient, and transplantation procedure influence the results. The use of expanded-criteria donors (ECDs) and the donor risk index (DRI) are strategies that have been proposed to increase the donors pool.

OBJECTIVE

We sought to study liver recipient survival before and after MELD implementation as well as the use of DRI.

METHODS

This retrospective study of prospectively collected data analyzed 1,786 liver recipients and their donors according to gender, age, cause of brain death, intensive care unit time, split liver, infection, ECD, cardiac arrest, cold ischemia time, waiting list time, and donor origin. MELD (without special scoring) and DRI were calculated from the recorded data. The periods of this study were 2004-2006 (pre-MELD) and 2006-2008 (post-MELD). For survival times, we performed the Kaplan-Meier method with log-rank tests and Cox regression analysis (prediction). The Kolmogorov-Sminorv test was used for sample comparisons.

RESULTS

The 1-year survivals were similar in the 2 periods (65.4% vs 67.6%). The predictive factors for death among the whole population were DRI >1.5, cold ischemia time ≥9 hours, MELD ≥25, female recipient, and longer waiting list time.

CONCLUSIONS

MELD is an important tool for allocation, resulting in a reduced waiting list, increased number of split-liver procedures, and use of ECDs without deterioration of survival times. DRI >1.7 was associated with shorter survival.

Human metapneumovirus infection in hematopoietic stem cell transplant recipients

Human metapneumovirus (hMPV) was described in 2001 and has been associated with both upper and lower respiratory tract infection (URTI and LRTI, respectively), especially in children, the elderly, and in immunocompromised patients. The objective of this study was to identify hMPV as the etiological agent of acute respiratory infection in hematopoietic stem cell transplant (HSCT) patients and to determine the clinical features of hMPV infection in these patients.

METHODS

The study was performed retrospectively in 769 respiratory samples obtained from immunocompromised patients submitted to HSCT over a period of 6 years. RNA was extracted by the guanidinium thiocyanate method, and reverse transcription polymerase chain reaction assay was performed to amplify a 928pb fragment of the hMPV N gene.

RESULTS

hMPV was present in 19 (2.5%) samples. The mean age of infected patients was 18.3+/-10.8 (range, 3-41). Sixty-six percent of hMPV infections occurred during autumn, winter, and spring months. Three episodes showed co-infection with more than 1 virus. Two patients (11.1%) were infected a few days into the conditioning period and 9 (50%) in the first 3 months after the transplant. The majority of patients (72.2%) presented URTI alone with flu-like symptoms (cough, fever, headache, wheezing), while 5 patients (27.8%) had LRTI (pneumonia). No patient died from complications associated with the hMPV infection.

CONCLUSIONS

hMPV has been reported as a respiratory pathogen in HSCT patients. We suggest that hMPV infection should be routinely investigated in this population, mainly in children, to prevent nosocomial transmission during transplant proceedings and to avoid the risk of progressing to complications due to LRTI.

Impact of respiratory infections by influenza viruses A and B in pediatrics patients from Federal University of Paraná, Brazil

The objective of the present study was to determine the impact of influenza virus on pediatric hospitalized patients. We retrospectively reviewed records of children with laboratory diagnoses, by cell culture and/or indirect immunofluorescence assay, of influenza virus seen in a period of 6 years. A total of 1,033 samples were analyzed, 45 (4.3%) of them being reactive to influenza virus. Thirty-one samples were positive to influenza A virus and 14 to influenza B. The frequency of hospitalization in intensive care and medical emergency was found to be high. Three (8.6%) patients died, two of them due to respiratory failure. Low frequency of influenza virus infection was observed in the study. The data suggest the need of more efficient epidemiological surveillance measures in order to obtain reliable information to better assess the impact of the virus on our region and determine the need of preventive measures, such as immunization.

Results of urgent liver retransplantation in the state of São Paulo, Brazil

The treatment of end-stage liver disease includes transplantation as a life-saving procedure although it has serious complications of hepatic artery thrombosis, liver dysfunction, or primary nonfunction, which frequently lead to the need for retransplantation. According to various reports, the incidence of retransplantation is around 10%. Given the critical organ shortage, the chance for a second transplant remains a controversial discussion in medical, ethical, and economic grounds because patient and graft survival rates after retransplantation are lower than those for primary transplantations. We retrospectively reviewed all of the urgent liver retransplants from October 2001 to February 2005 (52 months) by analyzing the number of retransplants, blood group, time between first and second liver transplantation, age, sex, and mortality. Data were obtained from the Transplantation System, State of Sao Paulo Health Secretariat. Among 1252 liver transplants performed during this period, 98 (7.82%) were urgent retransplantations. The primary procedure employed 955 (76.28%) deceased donors and 297 (23.72%) living donors. All 98 retransplants were performed using an organ from the pool of deceased donors. The retransplant rate was acceptable according to the literature, although we observed high rates of early mortality (<60 days), leading to a discussion of which patients had a better chance of survival and the best time to perform the second transplantation to use this scarce and precious resource in the best possible way.

Aphaereta sp. (Hymenoptera: Braconidae: Alysiinae) as a natural enemy to Peckia chrysostoma (Wiedemann) (Diptera: Sarcophagidae), in Brazil

This paper reports the first occurence of the parasite Aphaereta sp. (Hymenoptera: Braconidae: Alysiinae) which was collected from Peckia chrysostoma pupae (Diptera: Sarcophagidae) by means of traps containing some fish baits in a wood area close to the Agronomy college (Faculdade of Agronomia) in Itumbiara, Goiás, in the period from March to September, 2001. A total of 362 gregarious specimens of parasitoids from 26 pupae of P. chrysostoma. Aphaereta sp. was collected, with several individuals emerging from the same pupae.

TAF(II)170 interacts with the concave surface of TATA-binding protein to inhibit its DNA binding activity

The human RNA polymerase II transcription factor B-TFIID consists of TATA-binding protein (TBP) and the TBP-associated factor (TAF) TAF(II)170 and can rapidly redistribute over promoter DNA. Here we report the identification of human TBP-binding regions in human TAF(II)170. We have defined the TBP interaction domain of TAF(II)170 within three amino-terminal regions: residues 2 to 137, 290 to 381, and 380 to 460. Each region contains a pair of Huntington-elongation-A subunit-Tor repeats and exhibits species-specific interactions with TBP family members. Remarkably, the altered-specificity TBP mutant (TBP(AS)) containing a triple mutation in the concave surface is defective for binding the TAF(II)170 amino-terminal region of residues 1 to 504. Furthermore, within this region the TAF(II)170 residues 290 to 381 can inhibit the interaction between Drosophila TAF(II)230 (residues 2 to 81) and TBP through competition for the concave surface of TBP. Biochemical analyses of TBP binding to the TATA box indicated that TAF(II)170 region 290-381 inhibits TBP-DNA complex formation. Importantly, the TBP(AS) mutant is less sensitive to TAF(II)170 inhibition. Collectively, our results support a mechanism in which TAF(II)170 induces high-mobility DNA binding by TBP through reversible interactions with its concave DNA binding surface.

Behaviour of oligodendrocytes and Schwann cells in an experimental model of toxic demyelination of the central nervous system

Oligodendrocytes and Schwann cells are engaged in myelin production, maintenance and repairing respectively in the central nervous system (CNS) and the peripheral nervous system (PNS). Whereas oligodendrocytes act only within the CNS, Schwann cells are able to invade the CNS in order to make new myelin sheaths around demyelinated axons. Both cells have some limitations in their activities, i.e. oligodendrocytes are post-mitotic cells and Schwann cells only get into the CNS in the absence of astrocytes. Ethidium bromide (EB) is a gliotoxic chemical that when injected locally within the CNS, induce demyelination. In the EB model of demyelination, glial cells are destroyed early after intoxication and Schwann cells are free to approach the naked central axons. In normal Wistar rats, regeneration of lost myelin sheaths can be achieved as early as thirteen days after intoxication; in Wistar rats immunosuppressed with cyclophosphamide the process is delayed and in rats administered cyclosporine it may be accelerated. Aiming the enlightening of those complex processes, all events concerning the myelinating cells in an experimental model are herein presented and discussed.

Health effects of air pollution exposure on children and adolescents in São Paulo, Brazil

Children and adolescents have been considered more susceptible to the effects of air pollution than adults. In order to investigate the responses of children of different ages to air pollution exposure, daily records of hospital admissions for children in five age groups (equal or less than 2 years of age, 3-5, 6-13, 14-19, and all ages together, i.e., from 0-19 years of age) were obtained from January 1993 to November 1997 in São Paulo, Brazil, and were compared to daily records of PM10, O3, SO2, CO and NO2 concentrations in ambient air. For each age group a generalized additive Poisson regression was fitted controlling for smooth functions of time, temperature, humidity, and days of the week, with an additional indicator for holidays. Polynomial distributed lag models were used to estimate the 7-day cumulative effect of each pollutant. Children 2 years or less were the most susceptible to the effects of all five pollutants with an increase of 9.4% (95% CI: 7.9,10.9) in respiratory admissions associated with each interquartile range increase in PM10. The oldest group was the second most susceptible to air pollutants, with each interquartile range increase in PM10 associated with a 5.1% (95% CI: 0.3,9.8) increase in respiratory admissions. An interquartile range increase in CO was associated with an 11.3% (95% CI: 5.9,16.8) increase in respiratory hospitalizations. When a multipollutant model was used, the effect of PM10 on respiratory admissions for all ages together was unchanged, while the SO2 and the other pollutants effect was substantially reduced. This study showed that daily respiratory hospital admissions for children and adolescents in São Paulo increased with air pollution, and that the largest effects were found for the youngest (2 years or less) and oldest (14-19 years) age groups.

Health effects of air pollution exposure on children and adolescents in São Paulo, Brazil

Children and adolescents have been considered more susceptible to the effects of air pollution than adults. In order to investigate the responses of children of different ages to air pollution exposure, daily records of hospital admissions for children in five age groups (equal or less than 2 years of age, 3-5, 6-13, 14-19, and all ages together, i.e., from 0-19 years of age) were obtained from January 1993 to November 1997 in São Paulo, Brazil, and were compared to daily records of PM10, O3, SO2, CO and NO2 concentrations in ambient air. For each age group a generalized additive Poisson regression was fitted controlling for smooth functions of time, temperature, humidity, and days of the week, with an additional indicator for holidays. Polynomial distributed lag models were used to estimate the 7-day cumulative effect of each pollutant. Children 2 years or less were the most susceptible to the effects of all five pollutants with an increase of 9.4% (95% CI: 7.9,10.9) in respiratory admissions associated with each interquartile range increase in PM10. The oldest group was the second most susceptible to air pollutants, with each interquartile range increase in PM10 associated with a 5.1% (95% CI: 0.3,9.8) increase in respiratory admissions. An interquartile range increase in CO was associated with an 11.3% (95% CI: 5.9,16.8) increase in respiratory hospitalizations. When a multipollutant model was used, the effect of PM10 on respiratory admissions for all ages together was unchanged, while the SO2 and the other pollutants effect was substantially reduced. This study showed that daily respiratory hospital admissions for children and adolescents in São Paulo increased with air pollution, and that the largest effects were found for the youngest (2 years or less) and oldest (14-19 years) age groups.

The effect of cyclophosphamide on brainstem remyelination following local ethidium bromide injection in Wistar rats

Long-term cyclophosphamide (CY) treatment was used in male Wistar rats submitted to ethidium bromide (EB) demyelinating model to investigate ultrastructurally the drug effects on remyelination and on central nervous system (CNS) tissue repair. Demyelination was induced by a single 10 microl intracisternal injection of 0.1% EB solution and the rats anaesthetized and perfused through the heart from the 15th to the 31st day after injection. Brainstem sections were collected and processed for light and transmission electron microscopy studies. At different times after EB injection, it was observed the presence of macrophages in phagocytic activity and non-degraded myelin debris in the extracellular space, as well as remyelinated and demyelinated axons. Remyelination was carried out by both oligodendrocytes and Schwann cells, the latter notably around blood vessels and in areas of expanded extracellular space. It was also noted groups of infiltrating meningeal cells and astrocytes showing hypertrophic processes with numerous bundles of glial filaments. The rats treated with CY showed greater amounts of myelin-derived membranes than non-treated rats, suggesting a delay in the macrophage activity of removing myelin debris. Additionally oligodendrocyte remyelinating activity showed an incipient and restricted pattern, with clear predominance of naked axons. Rare lymphocytes were also found, as well as decreased neovascularization.

Environmental epidemiology applied to urban atmospheric pollution: a contribution from the Experimental Air Pollution Laboratory (LPAE)

Systematic investigation on the effects of human exposure to environmental pollution using scientific methodology only began in the 20th century as a consequence of several environmental accidents followed by an unexpected mortality increase above expected mortality and as a result of observational epidemiological and toxicological studies conducted on animals in developed countries. This article reports the experience of the Experimental Air Pollution Laboratory at the School of Medicine, University of São Paulo, concerning the respiratory system and pathophysiological mechanisms involved in responses to exposure to pollution using toxicological and experimental procedures, complemented by observational epidemiological studies conducted in the city of São Paulo. It also describes these epidemiological studies, pointing out that air pollution is harmful to public health, not only among susceptible groups but also in the general population, even when the concentration of pollutants is below the limits set by environmental legislation. The study provides valuable information to support the political and economic decision-making processes aimed at preserving the environment and enhancing quality of life.

A compilation of cellular transcription factor interactions with the HIV-1 LTR promoter

The human immunodeficiency virus type 1 (HIV-1) long terminal repeat (LTR) represents a model promoter system and the identification and characterisation of cellular proteins that interact with this region has provided a basic understanding about both general eukaryotic and HIV-1 proviral transcriptional regulation. To date a large number of sequence-specific DNA-protein interactions have been described for the HIV-1 LTR. The aim of this report is to provide a comprehensive, updated listing of these HIV-1 LTR interactions. It is intended as a reference point to facilitate on-going studies characterising the identity of cellular proteins interacting with the HIV-1 LTR and the functional role(s) of specific regions of the LTR for HIV-1 replication.

[Remuneration and productivity: the case of the Minas Gerais Hospital Foundation, Brazil, 1992-1995]

This article presents an analysis of the Minas Gerais State Hospital Foundation immediately after the introduction in its health services units in early 1993 of a new system of rewards for good performance and productivity, as a complement to salaried remuneration. Analysis was based on a cross-sectional study of changes in indicators of production and productivity in the Foundation during the 1992-1995 period. Data were obtained from hospitalization authorization forms, payment authorization guides, and bulletins from the Human Resource Administration. The strategy of conditional remuneration and incentives was adopted not only to step up production and productivity, but also to increase the employees' commitment to the institution. Analysis of the selected indicators appears to confirm other study results in that remuneration based on results (conditional incentives) leads to a positive change in the production level of services and productivity, even if it does not last for the long term. Study results also support the notion that such alternatives may be deliberately used as part of a more general strategy of organizational development and not only as an isolated element for concrete improvements in productivity.

Inflammatory response of the spinal cord to multiple episodes of blood-brain barrier disruption and toxic demyelination in Wistar rats

Multiple episodes of blood-brain barrier disruption were induced by sequential intraspinal injections of ethidium bromide. In addition to the barrier disruption, there was toxic demyelination and exposure of myelin components to the immune system. Twenty-seven 3-month-old Wistar rats received 2, 3 or 4 injections of 1 microliter of either 0.1% ethidium bromide in normal saline (19 rats) or 0.9% saline (8 rats) at different levels of the spinal cord. The time intervals between the injections ranged from 28 to 42 days. Ten days after the last injection, all rats were perfused with 2.5% glutaraldehyde. The spinal sections were evaluated macroscopically and by light and transmission electron microscopy. All the lesions demonstrated a mononuclear phagocytic infiltrate apparently removing myelin. Lymphocytes were not conspicuous and were found in only 34% of the lesions. No perivascular cuffings were detected. In older lesions (38 days and older) they were found only within Virchow-Robin spaces. This result suggests that multiple blood-brain barrier disruptions with demyelination and exposure of myelin components to the immune system were not sufficient to induce an immune-mediated reaction in the central nervous system.

Dynamics of remyelination in the brain of adult rats after exposure to ethidium bromide

Diseases of the central nervous system with limited prognosis, as multiple sclerosis, have led to the development of experimental models to study the pathophysiology of such diseases. The present investigation deals with the ethidium bromide (EB) model of demyelination with the objective to study the pathogenesis of encephalic demyelinating lesions. A single 10 microliters injection of 0.1% EB in 0.15 M saline was inoculated in the ventral surface of the pons of adult Wistar rats and after times ranging from 24 h to 30 days, the animals were anaesthetized and perfused with Karnovsky fixative for light and electron microscopy studies. From 3 to 7 days after the EB injection the tissue had developed a spongiotic aspect with intra- and extracellular swelling, demyelinating fibers and a number of necrotic glial cells. By 11 days the reactive phase had begun, and a large number of macrophages had migrated to the foci of the lesion, initiating the absorption of the necrotic tissue. In addition, there were oligodendrocyte-remyelinating nerve fibers and astrocytic gliosis. At 15 days Schwann cells-remyelinating fibers were first seen at the periphery of the lesion while the central area acquired a cystic pattern. The results obtained with the EB-demyelinating model in brain of adult rats showed that 1) remyelination by oligodendrocytes surpassed that by Schwann cells and 2) astrocytic processes were present at the areas remyelinated by the former and absent from those remyelinated by the latter.

Association between air pollution and intrauterine mortality in São Paulo, Brazil

The associations among daily counts of intrauterine mortality and pollutant concentrations (NO2, SO2, CO, O3, and particulate matter (3/4)10 microm) were investigated for the period ranging from January 1991 to December 1992 in the city of São Paulo, Brazil. We used Poisson regression techniques, adjusted for season and weather. The association between intrauterine mortality and air pollution was strong for NO2 (coefficient = 0.0013/ microg/m3; p<0.01) but lesser for SO2 (coefficient = 0.0005/ microg/m3; p<0.10) and CO (coefficient = 0.0223/ppm; p<0.10). A significant association was observed when an index that combined these three pollutants was considered in the models instead of considering each pollutant individually (p<0.01). These associations exhibited a short time lag, not over 5 days. In addition, some evidence of fetal exposure to air pollution was obtained by disclosing a significant association between the levels of carboxyhemoglobin of blood sampled from the umbilical cord and ambient CO levels in children delivered by nonsmoking pregnant women in the period from May to July 1995. Our results suggest that air pollution in São Paulo may promote adverse health effects on fetuses.

Association between air pollution and intrauterine mortality in São Paulo, Brazil

The associations among daily counts of intrauterine mortality and pollutant concentrations (NO2, SO2, CO, O3, and particulate matter (3/4)10 microm) were investigated for the period ranging from January 1991 to December 1992 in the city of São Paulo, Brazil. We used Poisson regression techniques, adjusted for season and weather. The association between intrauterine mortality and air pollution was strong for NO2 (coefficient = 0.0013/ microg/m3; p<0.01) but lesser for SO2 (coefficient = 0.0005/ microg/m3; p<0.10) and CO (coefficient = 0.0223/ppm; p<0.10). A significant association was observed when an index that combined these three pollutants was considered in the models instead of considering each pollutant individually (p<0.01). These associations exhibited a short time lag, not over 5 days. In addition, some evidence of fetal exposure to air pollution was obtained by disclosing a significant association between the levels of carboxyhemoglobin of blood sampled from the umbilical cord and ambient CO levels in children delivered by nonsmoking pregnant women in the period from May to July 1995. Our results suggest that air pollution in São Paulo may promote adverse health effects on fetuses.

Characterization and expression of a stage specific antigen by monoclonal antibody TRA 54 in testicular germ cells

To study the mechanism of spermatogenesis, we have isolated many monoclonal antibodies (mAb) which recognize specific steps of mouse germ cell differentiation and then have evaluated the specific expression and characterization of antigenic molecules using immunohistochemistry and Western blotting. Monoclonal antibody TRA 54 recognized specific organelles in germ cell cytoplasm from spermatocytes to spermatids; that is, a large granule was stained in mid-late pachytene, diplotene and secondary spermatocytes and in round spermatids at stage I while the acrosome of spermatids at steps 2-3 to step 12 were also positive. Thereafter, the antigens disappeared from spermatids at more advanced stages of differentiation. Western blots using TRA 54 revealed broad bands with approximate molecular weights of >200, 190 and 85 kDa in the testis. The expression of these antigens during testicular germ cell development should be of interest in relation to the biogenesis of organelles such as the chromatoid body and acrosome and will be a useful stage-specific molecular marker for the study of spermatogenesis.

A germ cell-specific nuclear antigen recognized by a monoclonal antibody raised against mouse testicular germ cells

A monoclonal antibody (mAb TRA 104) raised against mouse testicular germ cells was able to recognize the nuclei of testicular germ cells at all the stages of differentiation from embryonic gonocytes to spermatids and did not react with any somatic cells. The antigen recognized by mAb TRA 104 was exclusively present in testicular extracts. The molecular weights and isoelectric point (pI) of the antigens determined by Western blotting analysis were 60-110 kDa and 7.2, respectively. This antigen(s) is referred to as a germ cell-specific nuclear antigen(s) (GENA) since GENA was first detected specifically in the genital ridge at around 12 days of gestation by Western blotting analysis. In the testis, the expression increased gradually until adulthood whereas it was lost in the ovary by postpartum day 5. Thus, GENA is a molecule(s) exclusively present in the nuclei of germ cells and may be a useful marker with which to study the mechanism of germ cell development and differentiation at the molecular level.

[Demyelination and remyelination after multiple intramedullary injections of ethidium bromide in Wistar rats]

The ethidium bromide model of demyelination has been employed to study the central nervous system response to several episodes of demyelination. Twenty-seven Wistar rats received 2 to 4 intraspinal injections of 1 microliter of either 0.1% ethidium bromide in normal saline (19 rats) or saline 0.9% (8 rats) in different anatomical locations. The intervals between the injections ranged from 28 to 42 days. Ten days after the last injection all the rats were perfused with 2.5% glutaraldehyde. The spinal sections were evaluated macroscopically and by light and transmission electron microscopy. The lesions were typical of focal primary demyelination with preserved vascular structures and followed by remyelinization and varied in size and histological aspects. After multiple sequential ethidium bromide injections, the central nervous system seems to modify its response capacity to an inflammatory challenge although there is no change in its pattern of remyelination.