Low-frequency noise effects on the parotid gland of the Wistar rat.

BACKGROUND: Long-term low-frequency noise (LFN) (

[The occurrence of hepatitis B and delta virus infection within seven Amerindian ethnic groups in the Brazilian western Amazon]. / Ocorrência da infecção pelo vírus da hepatite B (VHB) e delta (VHD) em sete grupos indígenas do Estado do Amazonas.

HBV and HDV infections are a major health problem in the Amazon. This study evaluates the prevalence of these viruses within Indians groups, measuring the frequency of serological markers. The prevalence of past infection was 54.5% and HBsAg was found in 9.7%. An important variation of those markers was detected between villages, inclusively within the same ethnic group. None showed evidence of an acute infection. All HBeAg reactive were Apurinã, living in the same village and three of them from the same family. The prevalence of anti-HDT was 13.4% in HBsAg positive individuals. The authors observed high prevalence of HBV and HDV infection with the following pattern: low degree of infectivity, marked transmission in early ages, intra-familial dissemination, and lack of importance of vertical transmission. However, the results suggest that these viruses were not yet introduced effectively in some of the studied groups.

[Hepatitis A and hepatitis B seroprevalence in 4 centers in Brazil]. / Soroprevalência para hepatite A e hepatite B em quatro centros no Brasil.

The prevalence of antibodies to hepatitis A and B virus was assessed in 3,653 subjects across four regions of Brazil. The anti-HAV and anti-HBc seroprevalence were 64.7% and 7.9%, respectively. The highest anti-HAV (92.8%) and anti-HBc (21.4%) rates were seen in the Northern region. In other regions, anti-HAV seroprevalence over 90% was only reached in the more elderly, indicating an intermediate endemicity and a significantly higher anti-HAV prevalence was seen in the low socioeconomic group between 1-30 years. With respect to anti-HBc seroprevalence an increase was seen in adolescents and there was a significantly higher anti-HBc prevalence in the lower socioeconomic group between 1-20 years. A 3.1% anti-HBc prevalence was seen in one-year-old infants, suggesting a vertical transmission. The major findings of this study indicate that the pre-adolescent and adolescent population in some Brazilian cities are at greatest risk from both hepatitis A and B infection, but for different reasons.

Hepatitis B seroprevalence in Latin America.

The seroprevalence of hepatitis B was investigated in over 12,000 subjects in six countries of Latin America: Argentina, Brazil, Chile, the Dominican Republic, Mexico, and Venezuela. Each study population was stratified according to age, gender, and socioeconomic status. Antibodies against hepatitis B core antigen (anti-HBc) were measured in order to determine hepatitis B infection. The highest overall seroprevalence was found in the Dominican Republic (21.4%), followed by Brazil (7.9%), Venezuela (3.2%), Argentina (2.1%), Mexico (1.4%), and Chile (0.6%). In all the countries an increase in seroprevalence was found among persons 16 years old and older, suggesting sexual transmission as the major route of infection. In addition, comparatively high seroprevalence levels were seen at an early age in the Dominican Republic and Brazil, implicating a vertical route of transmission.

[Multicenter study of isolated micro-organisms resistant to antimicrobials in 10 Portuguese hospitals in 1994]. / Estudo multicêntrico de microrganismos isolados e de resistência aos antimicrobianos em dez hospitais Portugueses em 1994.

In 1994, Microbiology Laboratories of ten Portuguese hospitals analysed isolated microorganisms found in blood and urine samples and studied antimicrobial susceptibilities of the most frequent bacterial pathogens. From 63780 blood samples, the most frequent were Staphylococcus spp. and from 69189 urine samples significant numbers of Escherichia coli, Enterococcus spp., Pseudomonas aeruginosa and Candida spp. were isolated. Escherichia coli strains (c.7000) revealed a low percentage of resistance to antibiotics with the exceptions of ampicillin (48%) and co-trimoxazol (25%). Klebsiella pneumoniae isolates (c.2000) revealed important resistance to ampicillin (98%), cephalotin (31%), co-trimoxazol (38%) and gentamicin (28%), while values for 3rd generation cephalosporins varied among hospitals, with several strains showing phenotype of extended-spectrum beta-lactamase. A great variation in resistance values of P. aeruginosa (c.4000) was found in relation to the antibiotics as well as to the hospitals. Resistance to methicillin in S. aureus (c.6000) was high, reaching an average of 47%, and it was even higher with S. epidermidis (c.3000) and S. haemolyticus (c.650). Only vancomycin was always active against these strains. In E. faecalis (c.2500) resistance was of 2% to ampicillin, 35% to gentamicin, 45% to streptomycin and 1% to vancomycin. E. faecium isolates (c.300) showed the most worrying results with 70% resistance to ampicillin, 42% to gentamicin, 59% to streptomycin and 9% (30 strains isolated in 5 hospitals) to vancomycin. Vancomycin resistant strains were also resistant to all other antibiotics.

Articular cartilage changes mechanically induced "in vivo". An experimental method approach in animals.

A machine designed upon the principles of a crank lever mechanism was built to produce excessive use of the joints of small animals by means of continuous flexion-extension movements. Articular cartilage changes could be consistently produced after 5 to 10 days of exercise. Histochemical studies of the articular cartilage demonstrated a decrease in proteoglycan and an increase in acid phosphatase. These findings suggest that this animal model may be of value for the analysis of the earliest degenerative stages of the articular cartilage.

Measurements of stress and strain in live bone by electrical strain gage method.

Measurements of stress and strain in parts of musculokeletal system has been extensively studied in recent years. "In vitro" tests have contributed important information. The present study is an attempt to assess "in vivo" measurements using electrical extensometers attached to the bone with biocompatible adhesives permitting accurate measurements of strain over long periods of time. Even though its seems to be an adequate method there are some limitations to be considered. The problem involving tissue reaction, protections and isolation of the measuring unit, validity of measurements and determination of the principal directions of the strain are discussed. When adequately used the method may contribute to the knowledge and understanding of biomechanics of the musculokeletal system.