Soluble tumor necrosis factor alpha receptors (sTNF-Rs) in HIV-1-infected intravenous drug users: change in circulating sTNF-R type II level and survival for AIDS patients.

UNLABELLED: This study in intravenous drug users (IVDUs) investigated differences in serum soluble tumor necrosis factor types I and II (sTNFR-I and II) concentrations in HIV-1-infected IVDUs and controls. This study also investigated whether changes of sTNFRs concentration affect the risk of death among patients with AIDS. A cross-sectional study of 54 subjects with AIDS, 47 HIV-seropositive IVDUs, 47 HIV-seronegative IVDUs, and 21 healthy subjects showed that sTNFRs concentration increases from healthy controls to AIDS patients through HIV-seronegative and HIV-seropositive subjects (p < 0.01). sTNFR-I concentration, however, was shown to be similar in HIV-seronegative IVDUs and healthy controls. In the longitudinal study, serum concentration of sTNFRs was determined near AIDS diagnosis in 21 IVDUs and 1 year later (start for the survival study). Cox proportional hazards regression was performed to assess the prognostic value of percent change of sTNFR level alone and in combination with T lymphocyte subsets, HIV-p24 antigenemia and opportunistic infections for death within 240 days. Uni- and multivariate Cox modelling for dichotomised variables according to its median showed an increase of sTNFR-II by at least 30% to be single significant predictor of death: crude relative risk 3.69, p = 0.03; adjusted relative risk 5.67, p = 0.02. Mean survival was 126 days in 11 patients whose sTNFR-II level increased by at least 30%, and 176 days in 10 patients with less change in sTNFR-II (p = 0.02). CONCLUSIONS: sTNFRs concentration is higher in IVDUs than in healthy controls and is highest in AIDS patients. Survival of patients with AIDS is associated with variation in the concentration of sTNFR-II.

The changing pattern of human immunodeficiency virus type 1 infection in intravenous drug users. Results of a six-year seroprevalence study in Palermo, Italy.

A cross-sectional seroepidemiologic study was carried out between 1985 and 1990 in 1,567 heterosexual intravenous drug users who had been seen at the AIDS Regional Reference Center in Palermo, Italy, to evaluate the rate of human immunodeficiency virus type 1 (HIV-1) seroprevalence in this group and its long-term trend. Sixty serum samples collected from drug users in 1980 and 1983, before the founding of the Center (1985), were tested as well. Some demographic and behavioral risk factors were studied in a subgroup of intravenous drug users enrolled in 1985, 1987, and 1990 for their possible association with HIV-1. These factors were also studied in relation to hepatitis B virus infection, since both viruses share the same modes of spread. These drug users had a higher prevalence of markers for hepatitis B virus than of HIV-1 antibodies, and the prevalence rates in sera collected declined over time for both infections. The presence of both antibodies to HIV-1 and markers for hepatitis B virus was independently associated with the age of the drug user, the duration of drug use, and the year of serum collection. Antibodies to HIV-1 were observed more frequently in females than in males. No relation was found between education or employment status and the presence of HIV-1 antibodies or hepatitis B virus markers. Although new HIV-1 infections still occur, the decline in seroprevalence observed at the end of the 1980s might be related to modifications in social behavior among newer drug users, partial exhaustion of the susceptible population, and increasing risk awareness in more experienced users.

Free and antibody-complexed antigen and antibody profile in apparently healthy HIV seropositive individuals and in AIDS patients.

The pattern of free and antibody-complexed HIV antigen and the antibody profile were investigated retrospectively in 305 serum samples taken from 22 AIDS patients before and during the development of AIDS and from 40 apparently healthy seropositive individuals. Most AIDS patients were found positive for both free and complexed antigen and had high gp41 antibody titres but low or undetectable p24 antibody. Four different patterns of HIV antigenaemia were observed: 1) positive for both free and complexed antigen; 2) negative for free HIV antigen at first, but always positive for complexed antigen; 3) positive for free antigen without complexed antigen; and 4) negative for both free and complexed antigen. The development of immune complexes preceded the appearance of free antigen and might reflect the ongoing viral replication with antigen excess and binding of anticore antibodies. No correlation was found between the development of AIDS symptoms and either the duration of free antigen positivity or the level of antigenaemia. A different pattern was observed in apparently healthy seropositive individuals: 90% of whom had high antibody titres to p24 and gp41 and were persistently negative for free and complexed HIV antigen. This study demonstrates that testing HIV markers in sequentially collected serum samples from HIV seropositive individuals is a useful and simple tool for early identification of persons at risk of developing AIDS.

No evidence of HIV 2 infection in Sicily.

A seroepidemiological survey was carried out with the aim of establishing whether or not HIV 2 infection could be detected in Western Sicily. Two groups of sera were tested by EIA and WB assay against HIV 1 and HIV 2. 200 sera taken from North African immigrants in the Mazara del Vallo area, and 297 samples taken from AIDS-high risk groups individuals living in Palermo. None of the North African sera was positive to HIV 1 and/or HIV 2 by either techniques. 118 of the 297 sera from Palermo were HIV 1 positive by both techniques; 69 thereof also reacted to HIV 2 by EIA. Only six of these were confirmed by WB assay, showing a clear reactivity against the 140 and 105 HIV 2 glycoproteins. However, all six sera were considered merely cross-reactive to HIV 2, since none of them had neutralizing antibody to HIV 2 and the cross reactivity to glycoproteins of HIV 2 could be removed by absorbing them with HIV 1 infected cells. It seems therefore that HIV 2 has not yet reached our area. Early detection of the possible presence of this virus in our country could be obtained by improving both the surveillance and the effectiveness of laboratory tools for HIV 2 diagnosis.

Energy production in Ureaplasma urealyticum.

Ureaplasma urealyticum lacks the conventional mechanisms for adenosine 5-triphosphate (ATP) generation, such as glycolysis or arginine breakdown, present in other mycoplasmas. The possibility that ATP may be generated in these organisms through the formation of an ion gradient coupled to urea hydrolysis has been suggested by Masover and Hayflick (Ann NY Acad Sci 225:118-130, 1973). Our data have proved that ATP is produced when urea is added to resting ureaplasmal cells and its formation requires the concomitant activity of both cytoplasmic urease and membrane-bound ATPase and is drastically reduced by carbonylcyanide-m-chlorophenylhydrazine. Analysis of the optimal conditions for ATP synthesis in ureaplasmas indicates that this energetic process depends upon phosphate, urea, pH and ammonium ions in the reaction mixture. Particularly ammonium ions can interfere with the production of energy only when the starting pH is kept slightly basic. We have also shown that the changes in fluorescence intensity are directly related to the concentrations of the added urea and are inhibited by the presence of acetohydroxamic acid, carbonycyanide-m-chlorophenylhydrazine, and ammonium ions. It appears that urea hydrolysis can generate an electrical potential through NH4+ diffusion across the Ureaplasma membranes, but this diffusion is also dependent upon the external acidic pH of the reaction mixture.

Effects of urea phosphate, ammonium ions and pH on Ureaplasma ATP synthesis.

The effects of various reaction conditions and the influence of urea and its hydrolysis products on Ureaplasma ATP synthesis were assayed using of a pH stat system which avoids the unfavourable changes of the external pH. The results proved that ATP synthesis required the presence of an optimal phosphate concentration and was dependent on the urea content of the reaction mixture. The data suggest that urea is the energetic source for ureaplasma growth and ammonium ions and pH could interfere in an additive way with the production of energy, only when the starting pH of the medium is kept in a slightly basic range.

Influence of urease present in non viable organisms on the decline phase of Ureaplasma growth.

Broth cultures infected with ureaplasmas for 48 hrs were unable to support further growth of reinoculated ureaplasmas even when reconstituted with fresh ureaplasma medium. The apparent toxicity of spent cultures was ascribed to the presence of non viable ureaplasmas still containing a fully active urease since all the procedures adopted to abolish or reduce the urease activity restored the ability of these spent cultures to support ureaplasma growth. However, if the cause of the steep decline phase of ureaplasma cells could be reasonably ascribed to the enzymatic activity of urease present in the dead cells, the reasons for the poor field and the low titers achieved by the organisms during the logarithmic phase of growth remain an enigma.

Adenosine triphosphatase activity of Ureaplasma urealyticum.

Adenosine triphosphatase activity of U. urealyticum is an integral membrane-bound protein which cannot be detached from the membrane by mild treatment with EDTA in low-ionic strength media nor by ionic detergents which rapidly inactivated the enzyme. The enzyme was Mg++ dependent; Mn++ and Co++ could replace Mg++ to some extent. A slight stimulatory effect was also exerted by sodium and lithium. The enzyme showed a nucleotide triphosphatase activity, but ADP was hydrolyzed at close to 40% the rate of ATP and other nucleotide monophosphatase were hydrolyzed at a very slow rate. Oubain and oligomycin did not inhibit the adenosine triphosphatase activity, whereas DCCD, NBD-Cl and several sulfhydryl-blocking reagents strongly reduced its activity. The enzyme could not be stimulated by trypsin pretreatment. It seems that the complex enzyme is tightly linked to the lipid bilayer of the membrane and differs in many aspects from the F0-F1 (Mg++, Ca++)-ATPase of bacteria.

Adenosine 5'-triphosphate synthesis induced by urea hydrolysis in Ureaplasma urealyticum.

Although considerable attention has been devoted to the urea-hydrolyzing activity of Ureaplasma urealyticum, there is as yet no firmly established function for this enzyme. Present results support the idea that its activity generates a chemical gradient across the membrane which drives adenosine 5'-triphosphate synthesis through a chemiosmotic type of mechanism.

Cell fractions and enzymatic activities of Ureaplasma urealyticum.

The localization of some enzymic activities in cell fractions of Ureaplasma urealyticum was studied. A quantitative evaluation of the effectiveness of several cell lysis procedures was obtained by using labeled membranes and sucrose density gradient centrifugation. Ultrasonic treatment was found to be the most effective procedure for lysing the cells, whereas digitonin and osmotic shock caused the lysis of only 70 and 50% of the cells, respectively. The localization of selected enzymes in Ureaplasma cells resembled that found in other Mycoplasma species. Adenosine triphosphatase, ribonuclease, deoxyribonuclease, and p-nitrophenylphosphatase activities were located exclusively in the membrane fraction, whereas urease and L-histidine ammonia-lyase were located in the cytoplasm.

[Studies of influenza in Palermo, 1970-75]. / Indagini sull'influenza a Palermo, 1970-75.

Epidemiological surveillance of influenza was carried out in Palermo betwen 1970 and 1975. Antigenic structure of viral strains A/H3N2 isolated from influenza patients during winter outbreaks was studied in comparison with reference strains circulating in the same periods in other parts of the world. Antigenic drift of hemagglutinin, of neuraminidase, or of both, was observed in Palermo isolates, which were progressively different from Hong Kong/68 strain; 1973 and 1975 isolates were similar to A/England/72 and A/Port Chalmers/73. HI antibodies against Palermo isolates were titered in serum samples obtained from adults living in Palermo. Seronegativity for each strain progressively decreased from 1971 to 1975.

[Studies of diseases caused by hepatitis B virus on the island of Favignana]. / Indagini sulle affezioni da HBV nell'isola di Favignana.

731 serum samples were drawn from inhabitants of Favignana (Egadi Islands, total population 3,000). Presence of HBsAg and anti HBs was tested by R.I.A. Although only two cases of B Virus Hepatitis had been observed in the last 3 years, the overall positivity for HBsAg was 4.8% and for anti HBs 31.6%, showing a distribution by age and sex comparable to that observed in similar studies. The rather high prevalence of HBsAg in males over 70 deserves further investigations.

Immunological analysis of plasma membranes of a T-strain of mycoplasma (Ureaplasma urealyticum).

The cell membranes of a T-strain of mycoplasma, obtained by ultrasonic disruption, were as effective as whole organisms in eliciting metabolism-inhibiting and complement-fixing antibodies. The soluble fraction separated from cell membranes by centrifugation at 35,000 X g showed a minor ability to elicit an antibody response as measured by metabolism inhibition and complement fixation tests. After a further centrifugation at 100,000 X g, the immunogenic activity of the soluble fraction was completely lost. Immunogenic determinants in mycoplasma membranes could also be demonstrated by adsorption tests; cell membranes were more effective than soluble fractions in adsorbing antibody capacity from the immune sera against whole cells. It has been shown by further experiments that cell membranes have at least two major antigenic determinants, which differ either in chemical nature or in capacity to adsorb and evoke antibodies, characterized by different serological behaviors.

[The antigenic structure of Toxoplasma gondii. III. Behavior of human sera as compared with purified antigens]. / Sulla struttura antigene di Toxoplasma gondii. III. Comportamento di sieri umani nei confronti di antigeni purificati

263 human serum samples obtained from 9 controls and 42 patients with clinical diagnosis suggestive for toxoplasmosis were examined by means of Sabin and Feldman's dye test (DT) in comparison with complement fixation test (CF) with a whole toxoplasma antigen. 6 out of 9 controls and 21 out of 42 patients showed analogous behaviour in both methods while the remaining ones behaved differently. 24 out of the 42 patients as well as the 9 controls were chosen between these two groups (showing concordant or discordant DT/CF behaviour) to determine the presence or absence of anti-"polysaccharide" and anti-"protein" antibodies against purified antigens by means of CF test. Presence of anti-polysaccharide antibodies was shown in 15 subjects (4 out of 17 "DT/CF discordant" groups) and antiprotien antibodies in 8 patients (2 and 6 respectively in the two groups). Antibodies against these two purified antigens were never shown in the 9 normal people. Critical as well as hypothetical implications concerning the results so far obtained are discussed.