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R Cisterna

Publications and source records attributed to R Cisterna.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Historical cohort study on bacterial pneumonias as predictors of the progression of the human immunodeficiency virus disease].

BACKGROUND: Recognition of the importance of bacterial pneumonias in the context of HIV infection has continuously grown throughout the pandemia. It has recently been suggested that these may be predictors of progression of the disease. PATIENTS AND METHODS: The evolution of an historic cohort of patients with HIV infection who were studied in 1989 with pneumonia regarding the presentation of AIDS or death was investigated. A control cohort was established, being age matched for sex, CD4 lymphocyte count, previous HIV disease and the use of zidovudine. Kaplan-Meier curves of survival without AIDS were made and compared by the logarythmic range test. Other predictors of progression were studied by the Cox models. RESULTS: Forty-nine patients were studied in each group, with a total of 121 and 153 patients/year of follow up. Final events were counted in 33 and 27 cases, respectively (p = 0.11). The relative risk of progression was 1.55 (confidence interval of 95%, 0.93 to 2.56) for the group of pneumonias. The estimated relative risk (hazard) performed by a Cox model of proportional risks was however 1.85 (confidence interval of 95%: 1.05 to 3.25, p < 0.05) when the lymphocyte count adjustment was carried out according to the real values rather than by categories. CONCLUSIONS: The results of this historic cohort study support the existence of an association between history of bacterial pneumonia and the risk of HIV disease progression.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Relationship between outer membrane protein profiles and resistance to ceftazidime, imipenem, and ciprofloxacin in Pseudomonas aeruginosa isolates from bacteremic patients.

Outer membrane protein (OMP) profiles of 122 Pseudomonas aeruginosa isolates recovered from the blood of bacteremic patients were analyzed to relate alterations in the expression of OMPs with porin activity to resistance to imipenem, ceftazidime, and ciprofloxacin. Imipenem-resistant isolates lacked or expressed reduced amounts of porin OprD. In contrast, alterations of OMP profiles were absent in most ceftazidime-resistant isolates. Six of 12 ciprofloxacin-resistant isolates had normal OMP profiles. The remaining isolates showed alterations in the expression of either OprC, OprF, or OprD. In addition, imipenem- and ceftazidime-resistant isolates displayed a beta-lactamase activity compatible with that of a group 1 chromosomal cephalosporinase.

Anti-Infective Agents↗
PubMed1996

Detection of hepatitis C virus RNA in serum and peripheral blood mononuclear cells in patients with chronic hepatitis C treated with interferon alpha.

PCR was used to detect hepatitis C virus (HCV) RNA in serum and peripheral blood mononuclear cells (PBMCs) for evaluation of a six-month course of interferon therapy in 18 patients with histologically confirmed chronic hepatitis C. At follow-up six months after the end of therapy positive-stranded (genomic) and negative-stranded (anti-genomic, presumptive replicative intermediate) HCV RNA could be detected in PBMCs of all ten patients who either did not respond to therapy or suffered a relapse; genomic strand RNA was detected in five patients who responded but then relapsed. The study confirms that interferon therapy leads to inhibition of HCV replication but not eradication of the virus. Persistence of the virus at extrahepatic sites may explain its reactivation after cessation of interferon therapy.

Adult↗
PubMed1996

Emergence of resistance to beta-lactam agents in enterobacteriaceae species with group I beta-lactamases in Spain.

The contribution of induction and stable derepression of chromosomal group I beta-lactamases to beta-lactam antibiotics resistance was studied in clinical isolates of Enterobacteriaceae, collected from patients treated with these antibiotics. Multiple isolates of the same species from the same patient were characterized by different typing methods. Sonicated extracts of cells were assayed for chromosomal and plasmid-mediated beta-lactamases by isoelectric focusing and cloxacillin inhibition studies. The specific beta-lactamase activity, basal and induced with cefoxitin, was determined to differentiate strains with inducible or derepressed production of the enzyme. Induction of beta-lactamases was performed in each strain against the beta-lactams used in the therapy of each patient. Older penicillins resulted in a moderate to strong increase in beta-lactamase activity, whereas the results obtained with first-generation cephalosporins were species dependent. Expanded-spectrum cephalosporins were weak inducers of beta-lactamases. Indeed, the use of cefotaxime for treatment preceded the appearance of strains that produced chromosomal group I beta-lactamases constitutively. These strains showed a remarkable reduction in sensitivity to ureidopenicillins, carboxipenicillins, expanded-spectrum cephalosporins, and monobactams, but not to carbapenems.

Anti-Bacterial Agents↗
PubMed1996

Serratia rubidaea as an invasive pathogen.

Serratia rubidaea biotype 1 was isolated from the bile and blood of a patient with a bile tract carcinoma obstructing the common bile duct and who underwent invasive procedures. The infection was cleared after adequate treatment with antibiotics.

Anti-Bacterial Agents↗
PubMed1995

Association between HIV and other DNA viruses in vitro.

To investigate the association of human immunodeficiency virus (HIV) with various DNA viruses, including hepatitis B virus (HBV), cytomegalovirus (CMV) and Epstein-Barr virus, (EBV), simultaneous detection of HIV p24 antigen, HBV surface antigen and DNA, CMV-DNA and EBV-DNA expression was performed in phytohemagglutinin-stimulated peripheral blood mononuclear (PBMC) culture supernatants obtained from 54 individuals at risk for HIV infection. HIV expression in PBMC culture supernatants never occurred alone; expression of other viruses was always detected in the 24 samples expressing HIV antigen in vitro. Furthermore, in 16 patients expression of other viruses was detected without HIV expression, and in 14 patients none of the tested viruses were detected. These results indicate a strong association between the presence of HIV antibody and expression of DNA viruses in vitro (p = 0.0001). The coexpression of these viruses could be related to the evolution of HIV infection and AIDS.

Cells, Cultured↗
PubMed1995

Emergence of resistance to beta-lactam agents in Pseudomonas aeruginosa with group I beta-lactamases in Spain.

The contribution of induction and stable derepression of chromosomal class I beta-lactamases to beta-lactam antibiotic resistance was studied in clinical isolates of Pseudomonas aeruginosa collected from patients treated with beta-lactam antibiotics. Multiple isolates from the same patient were characterized by O-serotyping as a primary screen, combined with pyocin typing. Sonicated extracts of cells were assayed for chromosomal and plasmid-mediated beta-lactamases by isoelectric focusing and cloxacillin inhibition studies. The specific beta-lactamase activity, basal and induced, with cefoxitin was determined to differentiate strains with inducible or derepressed production of the enzyme. Beta-lactamase induction was performed in each strain against the beta-lactam agents used in the therapy of each patient. The observations showed that induction against older penicillins such as penicillin, amoxicillin, and amoxicillin/clavulanate resulted in a moderate to strong increase in beta-lactamase activity, whereas the results obtained with first-generation cephalosporins varied with the beta-lactam agent tested. Third-generation cephalosporins were weak inducers of beta-lactamases, and their use as therapy preceded the appearance of strains that produce chromosomal group I beta-lactamases constitutively. These strains showed a remarkable reduction in sensitivity to ureidopenicillins, carboxipenicillins, third-generation cephalosporins, and monobactams, but not to carbapenems.

Anti-Bacterial Agents↗
PubMed1995

Five-year survey of cefotaxime resistance in Spain.

During 1991-1995 a Spain collaborative study group surveyed the resistance to cefotaxime both in community as well as in hospital isolates of bacteria. The isolates tested during the study period of 5 years were 813, 875, 3631, 3184, and 3050 strains, respectively. Antimicrobial activity of cefotaxime was assayed by broth or agar microdilution, in accordance with criteria of the National Committee of Clinical Laboratory Standards (NCCLS). Cefotaxime resistance included 2.5% of all isolates: 2.6% Enterobacteriaceae, 1.7% Streptococcus pneumoniae, 0.5% Haemophilus influenzae, 0.0% Haemophilus spp., and 0.0% Moraxella catarrhalis. The overall incidence of resistance to cefotaxime decreased fro member of Enterobacteriaceae from 3.6% in 1991 to 2.5% in 1995. The incidence of resistance varied with the species and was highest in Enterobacter and in Citrobacter freundii.

Bacterial Infections↗
PubMed1994

Detection of hepatitis B virus DNA and determination of surface antigen expression in peripheral blood mononuclear cells from patients with AIDS.

The polymerase chain reaction (PCR) was used to analyze the presence of hepatitis B virus (HBV) DNA in serum and peripheral blood mononuclear cells (PBMCs) from 20 patients with AIDS with and without conventional HBV serological markers. DNA sequences of HBV were detected in PBMCs from 13 patients, nine of whom were positive for anti-HBc only and four of whom were also positive for anti-HBs. When PBMCs from patients were activated in culture with phytohemagglutinin, the presence of HBsAg could be detected in the culture supernatants from four of 13 patients with HBV DNA in their PBMCs; for two of the four, HBV DNA could also be detected in the culture supernatant after DNA amplification. It was observed that HBV DNA sequences found in PBMCs can be reactivated by mitogen stimulation in some HIV-1 infected patients.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Detection of human immunodeficiency virus type 1 by PCR before seroconversion in high-risk individuals who remain seronegative for prolonged periods.

HIV-1 seronegative patients at high risk for HIV infection were followed up. In 1990 PCR was positive for HIV DNA sequences in samples of 17 seronegative patients who continued to report for surveillance of HIV infection. There was clear evidence of seroconversion in four of these 17 seronegative patients, while in one patient an indeterminate result for HIV was repeatedly obtained in different samples. The other 12 patients continue to be seronegative without any evidence of HIV infection except the presence of provirus in peripheral blood mononuclear cells. It is important to apply the PCR technique together with tests to detect other virological and immunological markers, in order to identify seronegative carriers and thus avoid HIV transmission by them.

Adult↗