Study of the transdentinal diffusion of bioactive molecules.

In this work the mass transfer characteristics in a µ-tube that simulates a simplified dentinal tubule geometry are numerically investigated. The aim is to assess the key features that affect transdentinal diffusion of substances and consequently to define the necessary quantitative and qualitative issues related to a specific bioactive agent before its potential application in clinical practice. CFD simulations were performed in an S-shaped tapered micro-tube, while the code was validated using the non-intrusive optical measuring technique Laser Induced Fluorescence (LIF). As the phenomenon is one-dimensional, diffusion dominated and strongly dependent on the molecular size, the time needed for the concentration of released molecules to attain a required value can be controlled by their initial concentration. Thus, we propose a model, which is successfully verified by experimental data using a dentinal disc and which given the type of applied molecules and their critical pulpal concentration is able to estimate the initial concentration to be imposed.

A global reference for caesarean section rates (C-Model): a multicountry cross-sectional study.

OBJECTIVE: To generate a global reference for caesarean section (CS) rates at health facilities. DESIGN: Cross-sectional study. SETTING: Health facilities from 43 countries. POPULATION/SAMPLE: Thirty eight thousand three hundred and twenty-four women giving birth from 22 countries for model building and 10,045,875 women giving birth from 43 countries for model testing. METHODS: We hypothesised that mathematical models could determine the relationship between clinical-obstetric characteristics and CS. These models generated probabilities of CS that could be compared with the observed CS rates. We devised a three-step approach to generate the global benchmark of CS rates at health facilities: creation of a multi-country reference population, building mathematical models, and testing these models. MAIN OUTCOME MEASURES: Area under the ROC curves, diagnostic odds ratio, expected CS rate, observed CS rate. RESULTS: According to the different versions of the model, areas under the ROC curves suggested a good discriminatory capacity of C-Model, with summary estimates ranging from 0.832 to 0.844. The C-Model was able to generate expected CS rates adjusted for the case-mix of the obstetric population. We have also prepared an e-calculator to facilitate use of C-Model (www.who.int/reproductivehealth/publications/maternal_perinatal_health/c-model/en/). CONCLUSIONS: This article describes the development of a global reference for CS rates. Based on maternal characteristics, this tool was able to generate an individualised expected CS rate for health facilities or groups of health facilities. With C-Model, obstetric teams, health system managers, health facilities, health insurance companies, and governments can produce a customised reference CS rate for assessing use (and overuse) of CS. TWEETABLE ABSTRACT: The C-Model provides a customized benchmark for caesarean section rates in health facilities and systems.

Acute chagasic myocardiopathy after orthotopic liver transplantation with donor and recipient serologically negative for Trypanosoma cruzi: a case report.

Chagas disease (American trypanosomiasis) is caused by the protozoan parasite Trypanosoma cruzi. Chagas disease following solid-organ transplantation has occurred in Latin America. This report presents the occurrence of Chagas disease despite negative serological tests in both the donor and the recipient, as well as the effectiveness of treatment. A 21-year-old woman from the state of Sao Paulo (Brazil) underwent cadaveric donor liver transplantation in November 2005, due to cirrhosis of autoimmune etiology. Ten months after liver transplantation, she developed signs and symptoms of congestive heart failure (New York Heart Association functional class IV). The echocardiogram, which was normal preoperatively, showed dilated cardiac chambers, depressed left ventricular systolic function (ejection fraction = 35%) and moderate pulmonary hypertension. Clinical investigation discarded ischemic heart disease and autoimmune and other causes for heart failure. Immuno fluorescence (immunoglobulin M and immunoglobulin G) and hemagglutination tests for T cruzi were positive, and abundant T cruzi amastigotes were readily identified in myocardial biopsy specimens. Treatment with benznidazole for 2 months yielded an excellent clinical response. At the moment of submission, the patient remains in functional class I. This case highlighted that more appropriate screening for T cruzi infection is mandatory in potential donors and recipients of solid-organ transplants in regions where Chagas disease is prevalent. Moreover, it stressed that this diagnosis should always be considered in recipients who develop cardiac complications, since negative serological tests do not completely discard the possibility of disease transmission and since good results can be achieved with prompt trypanocidal therapy.

[Survival and infectious processes in pacients with AIDS: analysis based on initial serum vitamin A levels]. / Sobrevida e processos infecciosos em pacientes com AIDS: análise de acordo com os níveis séricos iniciais de vitamina A.

Patients with Aids (n = 39) were followed up for a maximum period of 36 weeks, after which the types and topographies of infectious complications presented and patient survival were analyzed and correlated with the vitamin A levels presented by the patients at the beginning of clinical follow-up. Twenty-one (53,8%) patients presented serum retinol levels below 1.6 micromol/L, 12 (57%) of whom had values lower than 1.05 micromol/L. There was no correlation between low serum vitamin A levels and the types or topographies of the infectious complications that occurred during the follow-up period. Although mean survival at the end of the 36 months follow-up period was similar for the two groups, patients with retinol deficiency presented a lower probability of survival during the first 24 months of follow-up compared to patients without hypovitaminosis A (8.44 x 1.42 months; p = 0.003).

[Survival of AIDS patients in a city in southeastern Brazil]. / Sobrevivência de pacientes com AIDS em uma cidade do sudeste brasileiro.

OBJECTIVE: To assess survival in patients diagnosed with AIDS in the city of Ribeirão Preto, Brazil, between 1986 and 1997. METHODS: The epidemiological records of 2,214 patients diagnosed during the study period were retrospectively reviewed. From those, 1,231 patients with at least 30 days of follow-up after the date of diagnosis were included in the study. Information concerning deaths was obtained from hospitals and vital-records offices. RESULTS: Survival for the group as a whole was 310 days (10.3 months) over the period of 1986 through 1997. Median survival was 362 days for 1986 to 1990, 260 days for 1991 to 1995, and 864 days for 1996 and 1997. The Kaplan-Meier survival curves and the log-rank test showed significant differences for the following variables: sex, age, period when diagnosis was made, and presence of candidiasis and of cerebral toxoplasmosis. Cox's regression showed an association between reduction of survival and the following variables: age (in comparison to individuals younger than 15 years, hazard ratio = 1.435 for age between 15 and 34 years, and 1.681 for age above 35 years); period of diagnosis (in comparison to the period of 1996 and 1997, hazard ratio = 1.682 for the period from 1986 to 1990, and 2.324 for the period from 1991 to 1995); and presence of candidiasis (hazard ratio = 1.391). The hazard ratio for the presence of cerebral toxoplasmosis was 1.063, with a probability value close to the limit of significance. CONCLUSIONS: Our results show a striking increase in survival in 1996 and 1997, coinciding with the availability and utilization of highly active antiretroviral drugs.

[Serological markers of hepatitis B in users of services at an HIV Testing Center]. / Marcadores sorológicos da hepatite B em usuários de um Centro de Testagem para o HIV.

The objective of this investigation was to study the prevalence of serological markers of hepatitis B and possible risk factors for this disease in a sample of 404 people who attended a Testing and Couseling Center for HIV in the city of Ribeirão Preto, São Paulo State, Brazil. The overall prevalence of serologic hepatitis B markers was 14.6%, equal to that obtained for anti-HBc. HBsAg and anti-HBc IgM showed prevalences of 1%. After adjustment using logistic regression, hepatitis B markers showed association with the following variables: age, place of residence, use of injectable drugs and positivity to anti-HIV. The overall prevalence of human immunodeficiency virus infection was 6.9%. Hepatitis B markers were detected in 55.6% among intravenous drug users and in 42.9% among those who tested positive for HIV, confirming literature findings which indicates high levels of infection in these specific population groups.

Marcadores sorológicos da hepatite B em usuários de um Centro de Testagem para o HIV / Serological markers of hepatitis B in users of services at an HIV Testing Center

The objective of this investigation was to study the prevalence of serological markers of hepatitis B and possible risk factors for this disease in a sample of 404 people who attended a Testing and Couseling Center for HIV in the city of Ribeirão Preto, São Paulo State, Brazil. The overall prevalence of serologic hepatitis B markers was 14.6%, equal to that obtained for anti-HBc. HBsAg and anti-HBc IgM showed prevalences of 1%. After adjustment using logistic regression, hepatitis B markers showed association with the following variables: age, place of residence, use of injectable drugs and positivity to anti-HIV. The overall prevalence of human immunodeficiency virus infection was 6.9%. Hepatitis B markers were detected in 55.6% among intravenous drug users and in 42.9% among those who tested positive for HIV, confirming literature findings which indicates high levels of infection in these specific population groups.

Esta investigação objetivou estudar a prevalência de marcadores sorológicos de infecção pelo vírus da hepatite B e analisar possíveis fatores de risco em 404 usuários submetidos à sorologia anti-HIV no Centro de Testagem e Aconselhamento de Ribeirão Preto, SP, Brasil. A prevalência global dos marcadores para o vírus da hepatite B foi de 14,6%, idêntica à encontrada para o anti-HBc, com valores de 1% para o HBsAg e anti-HBc IgM. Após ajuste por regressão logística, os marcadores de infecção do vírus B mostraram associação com as variáveis: idade, local de residência, uso de drogas endovenosas e positividade para o HIV. A prevalência de infecção pelo vírus da imunodeficiência humana foi de 6,9%. Marcadores do vírus B foram detectados em 55,6% dos usuários de drogas endovenosas e em 42,9% dos positivos ao vírus da imunodeficiência humana, confirmando altos índices de infecção nestes grupos específicos.

Transformation and trends in preventive and social medicine education at the undergraduate level in a Brazilian medical school.

In the present study we discuss some transformations in undergraduate training in Preventive and Social Medicine in the Department of Social Medicine of the Faculty of Medicine of Ribeiro Preto, University of So Paulo, from 1993 to 1999. Aspects of the relationship between medical training and the reorganization of local services of the Brazilian national health system, and between graduate teaching in Preventive and Social Medicine and medical education as a whole are discussed. The crisis in Preventive and Social Medicine and its influence of medical training are evaluated. Trends for the application of a body of knowledge of the specialty and for the relationship between the department and the medical school are discussed.

[Serological markers of hepatitis B in people submitted to blood testing in health care clinics]. / Marcadores sorológicos de hepatite B em indivíduos submetidos a exames de sangue em unidades de saúde.

OBJECTIVE: To study some of the epidemiological aspects of hepatitis B in a non-representative sample of patients seen in health care clinics. METHODS: The study population comprised 632 patients who were seen at health care clinics in the city of Ribeirão Preto, Brazil, for the purpose of blood testing, regardless the reason. After signing a written consent, an additional amount of blood was drawn from the same venous puncture site used to collect the original sample for the testing assigned to the patient at the health care clinic. A questionnaire was applied to each participant, looking for the presence of risk factors for hepatitis B. The blood samples were tested for HBV markers, using immunoenzimatic techniques. RESULTS: The prevalences of HBsAg and anti-HBcAg were 0.3% and 13.9%, respectively. By a logistic regression model, the following variables were significantly associated with the infection: age, time of residency in the city (higher risk among those living for a period less than one year), past history of hepatitis, incarceration and sexual behavior (higher risk among homosexual and bisexual males). CONCLUSIONS: The growing difficulties in obtaining blood samples from a representative group of patients, as done in classic surveys, make it necessary to look for alternative methodologies which can provide information concerning the presence of infectious agents in a community. Though the results cannot be generalized to the population as a whole, the methodology used conveyed some knowledge regarding the circulation of hepatitis B virus. In addition, it makes much easier to obtain agreement from the participants, since it does not add any invasive procedure. Despite the limitations, this methodology may be helpful in epidemiological surveillance of infectious agents known as producing asymptomatic infections in much of the population.

Abnormal uroporphyrin levels in chronic hepatitis C virus infection.

A strong association between hepatitis C virus (HCV) infection and porphyria cutanea tarda (PCT) has been observed, but the implications of the viral infection in the metabolism of porphyrins in patients without clinical manifestations of PCT are not known. The levels of porphyrin in plasma and uroporphyrin (URO) and coproporphyrin (COPRO) in 24-hour urine were measured in 156 patients with chronic HCV infection showing no clinical evidence of PCT. Levels of URO higher than the upper limit were observed in 35 of 156 patients (22.4%). The range and the mean values +/- standard deviation were 26-1,196 microg/24 hours and 82 +/- 204 microg/24 hours. Increased levels of COPRO and plasma porphyrin were observed in 12 of 156 patients (7.7%) and 2 of 156 patients (1.3%) respectively. There were no differences between patients with increased URO levels and patients with normal URO levels in terms of gender, age, risk factors for HCV infection, alcohol abuse, or hepatitis B viral infection. Transferrin saturation (p = 0.040), gamma glutamyl transpeptidase (p < 0.0001), aspartate aminotransferase (p = 0.006), and alanine aminotransferase (p = 0.040) were significantly higher in patients with abnormal URO than in patients with normal URO. The frequency of cirrhosis was higher, but not significantly different, in patients with increased URO (16.7%) compared with patients with normal URO (3.8%). The authors demonstrated that even without a clinical manifestation of PCT it is possible to detect abnormalities in the metabolism of porphyrins in patients with chronic HCV infection. The implications of these findings deserve additional investigation.

[Availability of voluntary prenatal HIV screening in primary health centers]. / Disponibilidade de sorologia anti-HIV como um teste voluntário na rotina do atendimento pré-natal em unidades básicas de saúde.

A summary of the main steps towards the implementation of anti-HIV testing for pregnant women in the city is presented. Starting from August 1996, voluntary HIV testing became available to pregnant women seen at primary health centers in Ribeirão Preto, SP (Brazil), as part of the Prenatal Care Program. By the end of 1998, 68.3% of the 17,589 women seeking prenatal care had been tested, resulting in a positivity rate of 0.76%.

Dengue control in Ribeirão Preto, São Paulo, Brazil.

Following an epidemic of type I dengue in late 1990, the municipality of Ribeirão Preto (State of São Paulo, Brazil) assumed direct responsibility for the control of Aedes aegypti larvae. Control activities are presented in this report and are based on popular participation in environmental management. Massive use of the communications media, participation by schoolchildren, constant contact with the population, and integration of various public agencies are the program's priorities. Although the drop in the number of susceptibles may have played a role in the reduction of cases after the initial epidemic, the intense preventive campaign certainly helped quell the disease in the city, since changes were observed in the behavior of the population towards potential breeding sites. The occurrence of new cases in recent years appears to be related to greater circulation of the virus in both the State of São Paulo and Brazil as a whole, indicating the need for control measures at the national and continental level, without which it will be difficult to maintain low transmission rates, even in areas submitted to intense preventive work

[Rabies epizootic in the urban area of Ribeirão Preto, São Paulo, Brazil]. / Epizootia de raiva na área urbana de Ribeirão Preto, SP, Brasil.

This report describes some epidemiological aspects of a rabies epizootic that started in 1995 in the urban area of Ribeirão Preto, SP, Brazil, and discusses its main causes. All laboratory confirmed cases were described according to a set of epidemiological variables. Simultaneously, information was raised concerning rabies vaccine coverage and epidemiological surveillance activities. In addition to one human case, 58 rabid animals were confirmed in 1995 (54 dogs, 3 cats. and 1 bat). There were 20 cases in 1996 (18 dogs and 2 cats). Geographical distribution was uneven in the city, with higher concentrations observed in the Western, Northern, and Southwestern sections, corresponding to the poorest areas. No seasonal variation was observed. The main reasons for the epizootic were low rabies vaccine coverage in animals and severe failures in epidemiological surveillance activities in the years immediately prior to 1995. This epizootic illustrates the risk of neglecting such activities, even in a city with a reasonably good health system, located in one of the most economically developed areas of the country. Vigorous preventive measures markedly reduced the number of cases.

[Analysis of agreement between self-reported and observed information on pubertal development among school girls]. / Análise de concordância entre informações referidas e observadas acerca do estadiamento pubertário entre escolares do sexo feminino.

AIM: To test the reliability of the self-classification concerning levels of breast and public hair development among female adolescents of different socioeconomic groups. MATERIAL AND METHOD: A total of 445 female adolescents attending three secondary schools located in Ribeirão Preto, State of S. Paulo, Brazil, were studied. After being familiarised with Tanner's tables of breast and public hair development, the adolescents were asked to self classify themselves according to these variables. The results were compared to those obtained by a physical examination carried out soon after. RESULTS: Agreement rates between referred and observed information on breast development varied from 57.3% to 65.2%. For public hair the values varied from 65.4% to 73.5%. Total agreement rates for breast and public hair development, when considered simultaneously, reached values below 50.0% in the three schools. However, high agreement rates were observed for some critical degrees, such as B2, B4 and PH4. CONCLUSIONS: Significant events, such as the beginning of pubertal development, the menarche and the showing down of the body's development growth could be determined with acceptable levels of agreement. The low agreement rates observed for the simultaneous analysis of the degree of both breast and public hair show the need for the perfecting of methodologies that can replace the physical examination of adolescents, once reliable information about pubertal development is obtained in field studies.

A case of human rabies in the urban area of Ribeirã Preto, SP, Brazil.

A 39-year old male patient was admitted to the University Hospital of the Faculty of Medicine of Ribeirão, Preto with signs and symptoms of sudden dyspnea, generalized myalgia and behavioral disorders. The initial suspicion was alcohol abstinence syndrome and the patient was referred for psychiatric and neurologic care. The evolution of the patient with a worsening of signs and symptoms, presence of crises of tachypnea, agitation, difficulty to swallow, irritability and hydrophobia, and his report of having been bitten by a suspected dog raised the hypothesis of rabies. The diagnosis was confirmed by examination of a corneal impression, biological tests in the cerebrospinal fluid (CSF) and saliva and visualization of Negri bodies in nervous tissue (direct immunofluorescence). The patient evolved with agitation, aggressiveness, and worsening tachypnea intercalating with apnea, and died on the 4th day after admission.