Evaluación de posibles métodos internacionales de referencia para la prueba de inhibición de la hemaglutinación para la rubéola: informe de un estudio en colaboración / Evaluation of candidate international reference methods for the rubella hemagglutination inhibition test: report of a collaborative study

Existen varios procedimientos en todo el mundo para efectuar la prueba de la inhibición de la hemaglutinación (IH) para detectar anticuerpos de la rubéola en sueros humanos. En este artículo se presenta un proyecto internacional patrocinado por la OMS para seleccionar uno de dichos procedimientos como método internacional de referencia (AU)

Evaluación de posibles metodos internaciónales de referencia para la prueba de inhibición de la hemaglutinación para la rubéola: informe de un estudio en colaboración / Evaluation of candidate international reference methods for rubella hemagglutination inhibition test: report of a collaborative study

Existen varios procedimientos en todo el mundo para efectuar la prueba de la inhibición de la hemaglutinación (IH) para detectar anticuerpos de la rubéola en sueros humanos. En este artículo se presenta un proyecto internacional de investigación patrocinado por la OMS para seleccionar uno de dichos procedimientos como método internacional de referencia

Strategies for prevention and control of hepatitis B and hepatocellular carcinoma.

Hepatitis B represents a serious public health problem in all parts of the world, and particularly in hyperendemic areas, where the majority of infections occur in childhood. As this infection in early life leads frequently to chronic infection, the prevalence rates of long-term sequelae, such as chronic active hepatitis and cirrhosis, are high. In addition, recent epidemiological, virological and molecular biological studies have provided evidence that persistent or past infection with hepatitis B virus plays an important role in the development of hepatocellular carcinoma (HCC). Although environmental control and the use of passive immunization have proved useful in reducing hepatitis B infections, the most important method of achieving widespread prevention of hepatitis B and its chronic sequelae is active immunization. Vaccines containing purified hepatitis B surface antigen (HBsAg) have been prepared and shown to be both highly immunogenic and efficacious. Depending on the different geographical patterns of hepatitis B prevalence and the availability of vaccine, a variety of vaccination strategies have been proposed ranging from limited to large-scale vaccine administration. Targeted vaccination of selected high-risk groups, including infants of HBsAg-carrier mothers, might be reserved for areas of low prevalence of infection, while large-scale vaccination should be considered for intermediate- and high-endemicity areas. In the latter case, effective control of hepatitis B could be achieved when sufficiently large population groups can be immunized prior to exposure, e.g., during infancy or early childhood. The prerequisite for large-scale vaccination campaigns is the production of large quantities of low-cost vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional response of lymphatic tissue in bronchogenic cancer.

The limiting factors in the treatment of bronchogenic cancer consist, from the bronchological point of view, in the possibility to estimate the advanced macromorphological stage of the disease with the determination of the degree of the affection of regional intrathoracic nodes. By the perbronchial route it is possible to obtain also a sufficient amount of material from unaffected nodes for purposes of testing their function. The testing of the spontaneous E-rosette formation is shortened, with the use of this method, by three quarters of an hour, but the possibility of obtaining a sufficient quantity of lymphocytes by the perbronchial puncture with the use of a fine needle is on average smaller than 50% in all types of bronchogenic cancer. It will be probably possible to introduce gradually also other immunological and biochemical methods of testing the function of the regional lymphatic tissue, as confirmed by the authors' experiences with immunological and biochemical investigations of bronchial washings with the use of 4 ml of the saline washing liquid. Experiences are thus far only preliminary and not unequivocal. Different alkaline under study, with better treatment results in patients treated with Cis-Platine, indicate phosphatase levels in patients with Penberol and Cis-Platine monotherapy in the series under study, with better treatment results in patients treated with Cis-Platine, indicate the possibility of using a further limiting aspect of cytostatic therapy.

Prevalence of markers of hepatitis B virus infection in various countries: a WHO collaborative study.

A WHO collaborative study on viral hepatitis B in which 21 laboratories in 20 countries participated is described. The aim of the study was to define the prevalence of hepatitis B surface antigen (HBsAg), its subtypes, and its antibody (anti-HBs) by age and sex and urban or rural residence in normal populations in different parts of the world. High-risk groups in the populations and patients with various diseases were also investigated. The results of the study confirmed that HBsAg and anti-HBs prevalence rates were higher in African and Asian countries than in the Americas, Australia, and northern and central Europe. Some eastern and southern European countries, however, were also shown to have high HBsAg and anti-HBs prevalence rates, comparable with those in Africa and Asia. In countries with low HBsAg and anti-HBs prevalence, there seems to be a gradual build-up during late childhood or early adolescence, whereas in countries with high HBsAg and its antibody prevalence, they were frequently detected in preschool children. Although the trend was towards a higher frequency of HBsAg and anti-HBs in urban than in rural and in male than in female populations, the differences were in most cases not significant. On the other hand, a significantly higher prevalence of markers of hepatitis B virus infection was seen in high-risk population groups than in normal populations. This was, however, clearly defined only in areas with low HBsAg and anti-HBs prevalence in the normal population. The geographical distribution of HBsAg subtypes showed a higher prevalence of the ad subdeterminant over ay in central European countries, whereas in eastern and southern Europe the ay subtype predominated. In West Africa, ayw was the only variant found, whereas in East Africa ad occurred more frequently than ay. In Australia, both adw and ayw subtypes were detected, whereas in the Far East and South-east Asia only adw and adr were seen.

The viral etiology of acute respiratory infections in children in Uganda.

The role of viruses in respiratory diseases of young children in Uganda was studied. A viral etiology was established in 36% of the infections investigated. The most important pathogens were found to be respiratory syncytial virus and parainfluenza viruses, which were responsible for 26% of infections investigated. They caused both upper and lower respiratory tract diseases. There was little or no seasonal variation in the etiology of these infections. Adenoviruses were found to be less important and were etiologically related to only 4% of respiratory disease cases. Influenza viruses and enteroviruses were also found to be associated with respiratory infections. However, they were less frequent and their role was insignificant. The role of multiple virus infections was also insignificant.

The program of the World Health Organization in the international surveillance of viral hepatitis B.

Viral hepatitis represents one of the important public health problems throughout the world. However, from the very inadequate and sometimes considerably inaccurate world data on the incidence, severity, and mortality of the disease, only tentative conclusions can be drawn. There is, however, reasonably good evidence derived from HB antigen testing that it is more common in tropical countries than in temperate zones. The need for introducing more complete reporting of hepatitis by age and sex, and differential reporting of hepatitis type A, type B and type unspecified is stressed. In addition, information on the WHO program on hepatitis B is presented.

Adsorption of Mycoplasma pneumoniae to neuraminic acid receptors of various cells and possible role in virulence.

Monkey, rat, and chicken tracheal epithelial cells, as well as monkey, rat, guinea pig, and chicken erythrocytes, adsorbed firmly to colonies of Mycoplasma pneumoniae and M. gallisepticum. Colonies of M. pulmonis also adsorbed erythrocytes but with less avidity than M. pneumoniae or M. gallisepticum; unlike the latter organisms, M. pulmonis did not adsorb tracheal epithelial cells. Colonies of M. orale type 1 and M. orale type 3 adsorbed only chicken red cells. Other mycoplasma species tested, including four of human origin and one of animal origin, did not adsorb red cells or epithelial cells. M. pneumoniae and M. gallisepticum appeared to attach to erythrocytes or tracheal epithelial cells by neuraminic acid receptors on these cells, whereas M. orale types 1 and 3 and M. pulmonis seemed to utilize another type or other types of receptors. Pretreatment of red cells or tracheal epithelial cells with receptor-destroying enzyme, neuraminidase, or influenza B virus removed the adsorption receptors for M. pneumoniae. Similarly, pretreatment of M. pneumoniae colonies with neuraminic acid-containing materials prevented adsorption of erythrocytes or respiratory tract cells. The adsorption sites on M. pneumoniae were specifically blocked by homologous but not heterologous antisera. This property made it possible to study the nature of the mycoplasma adsorption sites by testing the capacity of different fractions of the organism to block the action of adsorption-inhibiting antibodies. Such studies suggested that the mycoplasma binding sites were probably lipid or lipoprotein in nature. The glycerophospholipid hapten was implicated as one such site, since this serologically active hapten blocked the action of hemadsorption-inhibiting antibodies in M. pneumoniae rabbit antiserum. The affinity of M. pneumoniae for respiratory tract epithelium, unique among the mycoplasmas that infect man, may play a role in virulence, since this type of attachment provides an unusual opportunity for peroxide, secreted by the organism, to attack the tissue cell membrane without being rapidly destroyed by catalase or peroxidase present in extracellular body fluids.