The central dusty torus in the active nucleus of NGC 1068.

Active galactic nuclei (AGNs) display many energetic phenomena--broad emission lines, X-rays, relativistic jets, radio lobes--originating from matter falling onto a supermassive black hole. It is widely accepted that orientation effects play a major role in explaining the observational appearance of AGNs. Seen from certain directions, circum-nuclear dust clouds would block our view of the central powerhouse. Indirect evidence suggests that the dust clouds form a parsec-sized torus-shaped distribution. This explanation, however, remains unproved, as even the largest telescopes have not been able to resolve the dust structures. Here we report interferometric mid-infrared observations that spatially resolve these structures in the galaxy NGC 1068. The observations reveal warm (320 K) dust in a structure 2.1 parsec thick and 3.4 parsec in diameter, surrounding a smaller hot structure. As such a configuration of dust clouds would collapse in a time much shorter than the active phase of the AGN, this observation requires a continual input of kinetic energy to the cloud system from a source coexistent with the AGN.

Incidence of Chlamydia pneumoniae infection in vertically HIV-1 infected children.

The rate of seroconversion for antibody to Chlamydia pneumoniae was analysed in blood samples of 26 vertically HIV-1 infected children and 14 seroreverter children (HIV-negative children born to HIV-positive mothers) during a 3-year study period. Seroconversion for Chlamydia pneumoniae was found in 13 of 26 HIV-1 infected children and in 1 of 14 in the seroreverter group (P=0.013). A lower mean CD4+ cell count and p24 antigen positivity at enrolment were significantly associated with seroconversion for Chlamydia pneumoniae. Signs and symptoms of acute respiratory infection were recorded in the 30 to 40 days preceding collection of the blood samples showing seroconversion for Chlamydia pneumoniae in 8 of 13 HIV-1 infected children and in the single seroreverter. This study confirms the potential role of Chlamydia pneumoniae in the pathogenesis of respiratory tract infections in HIV-1 infected subjects.

Granulocyte-colony stimulating factor and erythropoietin therapy in children with human immunodeficiency virus infection.

To determine whether granulocyte-colony stimulating factor and erythropoietin are effective in the therapy of neutropenia and anaemia related to human immunodeficiency virus (HIV) infection and to anti-retroviral agents, we recruited 11 HIV-infected children (mean age 4 years 10 months). All the children were given granulocyte-colony stimulating factor at a dosage of 5 micrograms/kg twice or three times a week while erythropoietin was administered additionally to three patients at a dosage of 50 U/kg twice a week. Both agents were administered subcutaneously for at least 4 months. Leukocyte and neutrophil counts significantly increased during the treatment (after 1 months, P = 0.003 and P = 0.009, respectively). Erythropoietin prevented blood transfusions and increased haemoglobin levels in the three children treated. No side-effects were recorded during the administration of either agent. Granulocyte-colony stimulating factor and erythropoietin appear to be safe and useful agents in the management of HIV-infected children.

Opioid availability in Latin America: the Declaration of Florianópolis.

This declaration was formulated by consensus of the various government agencies and other organizations involved. It is hoped that it will be widely circulated.

Chlamydia pneumoniae seroprevalence in immunocompetent and immunocompromised populations in Milan.

BACKGROUND: Chlamydia pneumoniae is drawing increasing attention as an agent of respiratory tract infection. Specific antibody prevalence in western countries is low in preschool children and reaches more than 50% in adults. However, little is known about the prevalence of this infection in immunocompromised subjects such as HIV-I infected patients. The aim of this study was to evaluate the seroprevalence of Chl pneumoniae in immunocompetent and immunocompromised (HIV-1 infected) paediatric and adult populations. METHODS: Between March 1991 and September 1992 764 healthy subjects (421 men and 343 women, age range six months-81 years), 96 HIV-I infected (73 men and 23 women, age range 18-35 years) and 126 HIV-I negative intravenous drug users (92 men and 34 women, age range 18-37 years), and 50 children (23 boys and 27 girls, age range 8-123 months) with vertically transmitted HIV-I infection were studied. For each subject an HIV-I test (ELISA and Western blot) was performed, together with a microimmunofluorescence test for IgG and IgM antibodies to Chl pneumoniae specific antigen (TW-183). RESULTS: In the healthy population a low prevalence (11%) was observed in children under 10 years of age, which increased progressively to 58% in adults over 70 years. In the HIV-I infected population Chl pneumoniae seroprevalence was higher than in immunocompetent controls (children, 26% v 11%; drug users, 60% v 40%). Moreover, in drug users this difference was also observed in comparison with HIV-1 negative intravenous drug users (60% v 33%). CONCLUSIONS: Our data on Chl pneumoniae seroprevalence in a healthy population are consistent with those reported by others in western countries. Moreover, HIV-I infected subjects seem to be at higher risk of developing Chl pneumoniae infections.

Comparison of variable region 3 sequences of human immunodeficiency virus type 1 from infected children with the RNA and DNA sequences of the virus populations of their mothers.

We have compared the variable region 3 sequences from 10 human immunodeficiency virus type 1 (HIV-1)-infected infants to virus sequences from the corresponding mothers. The sequences were derived from DNA of uncultured peripheral blood mononuclear cells (PBMC), DNA of cultured PBMC, and RNA from serum collected at or shortly after delivery. The infected infants, in contrast to the mothers, harbored homogeneous virus populations. Comparison of sequences from the children and clones derived from DNA of the corresponding mothers showed that the transmitted virus represented either a minor or a major virus population of the mother. In contrast to an earlier study, we found no evidence of selection of minor virus variants during transmission. Furthermore, the transmitted virus variant did not show any characteristic molecular features. In some cases the transmitted virus was more related to the virus RNA population of the mother and in other cases it was more related to the virus DNA population. This suggests that either cell-free or cell-associated virus may be transmitted. These data will help AIDS researchers to understand the mechanism of transmission and to plan strategies for prevention of transmission.

Immunization in children with HIV seropositivity at birth: antibody response to polio vaccine and tetanus toxoid.

OBJECTIVE: To evaluate the humoral response to routine childhood immunization of HIV-infected children. DESIGN: Response rate, antibody titres and persistence after polio and tetanus vaccination were compared in 72 children with HIV seropositivity at birth and divided according to HIV infection status as determined by clinical and laboratory tests. METHODS: Polio antibodies were titred in a microneutralization test (positive titres, > or = 1:4), and antibody to tetanus toxoid with a passive haemagglutination method (protective titres, > or = 1:1024). RESULTS: The response rates to polio and tetanus vaccination (> 80 and > 75%) were similar in the HIV-infected and non-infected children, as were antibody levels. In the subgroup with sera obtained some months after the last dose of vaccine, polio antibody levels decreased in all four HIV-infected and in three of the seven non-infected children; protective tetanus antitoxin levels were detected in three of the six infected and in all three non-infected children. CONCLUSIONS: This study demonstrates the ability of children with HIV infection to respond adequately to the two vaccines considered, although tetanus antitoxin levels were inferior, compared with those in the seroreverted children. The unsatisfactory antibody levels observed in the admittedly few HIV-positive children studied some months after the last vaccination could be the result of a lower initial protective level and not necessarily an expression of severely impaired immunocompetence. The administration of booster doses in addition to the traditional immunization schedule could be useful in children with HIV infection.

Mother-to-child transmission of human immunodeficiency virus type 1: risk of infection and correlates of transmission.

One thousand eight hundred eighty-seven children born to human immunodeficiency virus type 1 (HIV-1) seropositive mothers, including 1045 infants prospectively followed up from birth, were studied. Intravenous drug use was the most frequent maternal risk factor, although the percentage of women infected by sexual contact increased from 5.8% in 1985 to 28.5% in 1990. Of the 551 first children followed up from birth and older than 15 months of age, 101 (18.3%) acquired infection and seroconverted to HIV-1. Another 31 (5.6%) asymptomatic seronegative children showed the presence of viral markers, for an apparent mother-to-offspring transmission rate of 23.9%. Overlapping results were seen in 22 second-born children followed up from birth. Of 59 sibships with definite infection status, when the first child was infected, 14 (40%) of 35 second children were infected, whereas when the first child was not infected, only 2 of 24 (8.3%) second children were infected. Discordance in HIV-1 transmission was found in 1 of 18 pairs of twins. Univariate and multivariate analyses of possible risk factors for HIV-1 transmission performed on the entire population of children and in the cohort of those followed up from birth were basically in agreement in indicating that the development of symptoms in the mother before delivery and breast-feeding (indeed adopted in only 22 infants in whom HIV-1 infection was identified at birth) were significantly and independently associated with a higher transmission rate. In addition, girls were more frequently infected than boys.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody response to inactivated polio vaccine (E-IPV) in children born to HIV positive mothers.

In order to evaluate the response to immunization of HIV-infected children we studied the humoral response to an enhanced potency inactivated poliovaccine (E-IPV) of 43 children born of HIV seropositive mothers. All these subjects have been followed for 32 (15-48) months in order to ascertain their infection status. After a course of 2 doses of E-IPV, 88% of children had neutralizing antibody (n.a.) titers greater than 1:4 to the 3 poliovirus serotypes and 100% to at least 2 polio strains. No statistically significant differences both as rates of n.a. positive subjects and as antibody levels were found between HIV infected children and those who lost HIV antibodies. The poorest response was observed in subjects with full-blown immunodeficiency (CD4 less than 1000/mm3, reduced response to PWM). Sixteen children also received a booster dose of vaccine one year after the completion of the primary cycle. Infected and non-infected subjects responded to the same extent with high levels of n.a. to this immunization. Interestingly, the recall dose was also able to induce high n.a. titers in those HIV infected children who showed significant decreases of n.a. titers in the months following the end of the primary cycle.

Myelokathexis associated with multiple congenital malformations: immunological study on phagocytic cells and lymphocytes.

A 5-year-old boy was first seen at the age of 11 months when he presented with growth retardation, skeletal dysmorphisms and neutropenia. Since then he has remained leukopenic except when he has pulmonary infections with a marked leukocytosis. Despite his neutropenia, marked myeloid hyperplasia was evident on marrow smear examination; many cells showed abnormally hypersegmented nuclei, with unusual shape or pyknotic nuclei. Phagocytic cells showed impaired phagocytosis, candidacidal activity, metabolic burst and chemotaxis. Moreover, the patient's serum generated less chemotactic activity than normal serum. These data indicate a selectively complex defect of the neutrophil during differentiation associated with the presence of an inhibitor of chemotactic factors in the patient's serum.