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Biomedical subjects

I Ruiz

Publications and source records attributed to I Ruiz.

At least 55 records · Page 3Linked to original sources
PubMed1997

Treatment of experimental pneumonia due to penicillin-resistant Streptococcus pneumoniae in immunocompetent rats.

A model of pneumonia due to Streptococcus pneumoniae resistant to penicillin was developed in immunocompetent Wistar rats and was used to evaluate the efficacies of different doses of penicillin, cefotaxime, cefpirome, and vancomycin. Adult Wistar rats were challenged by intratracheal inoculation with 3 x 10(9) CFU of one strain of S. pneumoniae resistant to penicillin (MICs of penicillin, cefotaxime, cefpirome, and vancomycin, 2, 1, 0.5, and 0.5 microg/ml, respectively) suspended in brain heart broth supplemented with 0.7% agar. The rats experienced a fatal pneumonia, dying within 5 days and with peak mortality (70 to 80%) occurring 48 to 72 h after infection, and the bacterial counts in the lungs persisted from 8.87 +/- 0.3 log10 CFU/g of lung at 24 h of the infection to 9.1 +/- 0.3 log10 CFU/g at 72 h. Four hours after infection the animals were randomized into the following treatment groups: (i) control without treatment, (ii) penicillin G at 100,000 IU/kg of body weight every 2 h, (iii) penicillin G at 250,000 IU/kg every 2 h, (iv) cefotaxime at 100 mg/kg every 2 h, (v) cefpirome at 200 mg/kg every 2 h, and (vi) vancomycin at 50 mg/kg every 8 h. Two different protocols were used for the therapeutic efficacy studies: four doses of beta-lactams and one dose of vancomycin or eight doses of beta-lactams and two doses of vancomycin. Results of the therapy for experimental pneumonia caused by penicillin-resistant S. pneumoniae showed that initially, all the antimicrobial agents tested had similar efficacies, but when we prolonged the treatment, higher doses of penicillin, cefotaxime, and cefpirome were more effective than penicillin at lower doses in decreasing the residual bacterial titers in the lungs. Also, when we extended the treatment, vancomycin was more efficacious than penicillin at lower doses but was less efficacious than higher doses of penicillin or cefpirome. The model that we have developed is simple and amenable for inducing pneumonia in immunocompetent rats and could be used to explore the pathophysiology and to evaluate optimal therapy of this infection in the immunocompetent host.

Animals↗
PubMed1997

Six cycles of ABVD in the treatment of stage I and II Hodgkin's lymphoma: a pilot study.

PURPOSE: Chemotherapy is the standard treatment in advanced Hodgkin's lymphoma and a therapeutic alternative for early stages. Although polychemotherapy with doxorubicin, bleomycin, vinblastine, and dacarbazine (ABVD) is equivalent or superior to mechloretamine, vincristine, procarbazine, and prednisone (MOPP) in advanced disease, no series have been published using ABVD without associated radiotherapy in early stages. We report the results obtained with the administration of six cycles of ABVD alone in clinical stage I and II disease. PATIENTS AND METHODS: From January 1990 to October 1994, 23 patients with stage I or II Hodgkin's lymphoma were treated with six cycles of ABVD; six patients who met the criteria for mediastinal bulky disease also received radiotherapy to the mediastinum. RESULTS: After six cycles, 20 complete responses (CRs) and three partial responses (PRs), which became CRs after radiotherapy, were obtained. Toxicity was moderate and manageable. With a median follow-up duration of 37 months (range, 12 to 75), three patients have relapsed and one has died. Overall and progression-free survival rates at 42 months are 95% and 84%, respectively. CONCLUSION: Six cycles of ABVD are effective and safe in the treatment of stage I and II Hodgkin's lymphoma, at least in the short term, but long-term observation data are not yet available.

Adolescent↗
PubMed1997

Structure-activity relationships in quinoline Reissert derivatives with HIV-1 reverse transcriptase inhibitory activity.

The relationship between the chemical structure and the HIV-1 RT inhibitory activity has been studied for a series of quinoline derivatives. Two methods were used: a standard QSAR analysis, by combining the methods of Hansch and Free-Wilson, and an analysis using quantum chemistry indices as descriptor parameters, by the semiempirical method AM1. The equations obtained lead to the proposal that the activity of the compounds increases, mainly, with the presence of electron-withdrawing substituents in position 6 of the quinoline ring that cause a decrease in the energy from the molecular orbital LUMO. In turn, this fact leads to the proposal that the most important interaction of these compounds with the HIV-1 RT is a charge transfer type interaction, with the quinoline aromatic ring acting as acceptor.

Anti-HIV Agents↗
PubMed1997

Synthesis and evaluation of new Reissert analogs as HIV-1 RT inhibitors. 2. Benzo[f]quinoline and pyridine derivatives.

The synthesis and preliminary evaluation of new benzo[f]quinoline and pyridine derivatives, obtained by application of the Reissert method and its modifications, as HIV-1 RT inhibitors and anti-infectives are presented. The most active products against HIV-1 RT wild type are the ethyl 2-cyano-1,2-dihydrobenzo[f]quinoline-1-carboxylate 2b, propyl 2-cyano-1,2-dihydrobenzo[f]quinoline-1-carboxylate 2c, and 2-cyano-1-(2'-furoyl)-1,2-dihydrobenzo[f]quinoline 2n, which maintain their activity against the mutant type P236L, resulting inactive against the Y181C type. Using the data previously obtained by our research team for analogous series derived from quinoline as reference, the compounds which have now been obtained present an increase in the cytotoxic character attributable to the introduction of a benzene ring fused with the quinoline base nucleus, as well as a decrease of the activity as HIV-1 RT inhibitors when the quinoline benzenic ring is eliminated.

Anti-HIV Agents↗
PubMed1997

Synthesis and evaluation of new Reissert analogs as HIV-1 reverse transcriptase inhibitors. 1. Quinoline and quinoxaline derivatives.

The synthesis and preliminary evaluation of new quinoline and quinoxaline derivatives (obtained by applying the original Reissert method, conveniently modified) as HIV-1 Reverse Transcriptase (RT) inhibitors are presented in this paper; likewise, the first structure-activity relationships are also proposed. Propyl 2-cyano-1(2H)-quinolin-carboxylate 2e, isopropyl 2-cyano-1 (2H)-quinolincarboxylate 2f, butyl 2-cyano-1 (2H)-quinolincarboxylate 2g and isobutyl 2-cyano-1 (2H)-quinolincarboxylate 2h have been selected as lead compounds. These compounds are active against the HIV-1 RT mutant type P236L (2f, IC50 = 1.2 microM) and present activity as anti-infective agents in HLT41acZ-1IIIB cells, showing no cytotoxicity at the active concentrations.

Anti-HIV Agents↗
PubMed1996

[Pleural cryptococcosis in patients with human immunodeficiency virus infection].

Four cases of pleural cryptococcosis as the form of onset of cryptococcosis in patients with human immunodeficiency virus (HIV) infection are reported. In two out of the four cases cryptococci were simultaneously isolated in other localizations (blood and meninges). In the two remaining patients the pleura was the only site of the disease, with serum determination of the cryptococci antigen being negative in one. The four patients evolved favourably, with three being exclusively treated with fluconazol. Pleuritis is an infrequent manifestation in cryptococcosis although it may be the form of onset and the only localization of the disease. Only 10 cases have been reported in patients with HIV infection. The present four cases represent 11% of the authors' series of cryptococcosis in AIDS patients. The diagnostic possibility of cryptococcosis should be considered in patients with human immunodeficiency virus infection presenting pleural effusion.

Acquired Immunodeficiency Syndrome↗
PubMed1996

Prevalence of antibiotics to hepatitis C in a population of intravenous drug users in Valencia, Spain, 1990-1992.

BACKGROUND: Hepatitis C has been related to other viral diseases such as the human immunodeficiency virus infection (HIV) or hepatitis B (HBV). The objective of this study was to estimate the prevalence and determinants of antibodies to hepatitis C virus (HCV) in intravenous drug users (IVDU) in Valencia (Spain) and to compare the seroprevalence between the HCV, HIV and HBV in this high risk group. METHODS: A cross-sectional study was conducted in a sample of 1056 current IVDU from the Valencia area who attended the city's AIDS Information Centre between January 1990 and December 1992. Information on sociodemographic, sexual behaviour, and drug use variables was collected by means of a structured questionnaire. Antibodies to HCV, HIV and HBV were assayed by ELISA test. RESULTS: The seroprevalence of HCV for the whole period was 85.5% (95% confidence interval [CI]: 83.2-87.5%), ranging from 76.5% in 1990 (95% CI: 71.9-81.1%) to 87.8% in 1992 (95% CI: 82.5-93.1%). Year of testing and prevalence of HBV markers showed an independent association with HCV seroprevalence. When only IVDU aged < 25 years were analysed, sharing of needles also appeared as an independent dominant. Of those IVDU with less than one year of addiction, 69% were HCV seropositive compared with 41% for HBV and 14% for HIV. CONCLUSIONS: Intravenous drug users in Valencia showed one of the highest reported hepatitis C seroprevalences (85.5%). A more efficient parenteral transmission of hepatitis C virus than HBV or HIV is suggested.

Adult↗
PubMed1996

Benzodiazepine use in Chile: impact of availability on use, abuse, and dependence.

This study tested the hypothesis whether over-the-counter benzodiazepine availability influenced patterns of benzodiazepine use, abuse, and dependence in Chile. If over-the-counter availability represents a major risk factor leading to benzodiazepine substance use disorders, rates of abuse, and dependence would be significantly higher among over-the-counter benzodiazepine users than among prescription drug users. The study was a household survey of a stratified sample (N = 1,500) of the Santiago (Chile) population performed by trained interviewers. Data were collected by structured questionnaires on demographic characteristics, drug use, psychoactive substance use disorders, and other psychosocial variables. Past-year prevalence of benzodiazepine use was 31.4%, daily use of benzodiazepines for > or = 12 months, 5.9%, and subjects who met DSM-III-R criteria for dependence, 3.3%. Seventy-four percent of subjects obtained the benzodiazepine over-the-counter (always 45%; sometimes 29%). No subject acknowledged recreational benzodiazepine use or met criteria for benzodiazepine abuse. Use, long-term use, and dependence occurred equally frequently among both over-the-counter and prescription benzodiazepine users. Results suggest that although over-the-counter availability increases benzodiazepine use, it is not a major risk factor that leads to benzodiazepine abuse and/or dependence.

Adolescent↗
PubMed1996

Water quality parameters associated with Aeromonas spp-affected hatcheries.

This study investigates the role of water quality parameters as possible risk or protection factors in Aeromonas spp-affected rainbow trout hatcheries in northeastern Spain. The results revealed an association between oxygen concentration, ammonia concentration and total dissolved solids (TDS) with the prevalence of Aeromonas spp cases on the affected fish farms. The oxygen and ammonia concentrations acted as risk factors when their values were lower than 7.06 mg/L or higher than 0.05 mg/L, respectively, generating odds ratio (OR) values of 2.0 and 2.3. TDS levels, however, acted as a protective factor (OR = 0.39), from an epidemiological point of view but not statistically, when the values were outside the normal range, 199-261 mg/L. On a multivariate level, fish farms exposed to all the associated factors at the same time, had a risk of being affected by Aeromonas spp that was 1.74 times higher than farms with normal quality parameters; the risk increased when TDS had a normal value and it decreased when oxygen and/or ammonia concentrations had normal values.

Aeromonas↗
PubMed1996

Furunculosis control using a paraimmunization stimulant (Baypamun) in rainbow trout.

The effect of Baypamun, a non-specific immune system stimulant, on the treatment and control of furunculosis was studied in experimentally infected rainbow trout. A statistically significant association between the Baypamun treatment and a reduction in cumulative incidence of the clinical symptoms of Furunculosis and the infection level, despite the presence of the bacteria in blood and organs was observed. A reduction in the mortality rate in Baypamun-treated fish was also observed but this was not statistically significant. The results suggest that the treatment of fish diseases with non-specific immune stimulants could be, in the future, a good defense strategy leading to a reduction in disease symptoms and a greater control of the asymptomatic carriers after an outbreak.

Adjuvants, Immunologic↗
PubMed1995

Trends in incidence and prevalence of HIV-1 infection in intravenous drug users in Valencia, Spain.

Our objective was to describe and compare the trends of incidence and prevalence of HIV-1 infection in intravenous drug users (IDUs) in Valencia, Spain in 1987-1992. A cohort study was carried out in AIDS Information Centers located in the Valencia Region (Spain). Point seroprevalence was calculated for in each year according to HIV status at the first contact. Incidence annual rates were calculated from those IDUs identified as seronegative in their first visit and who returned for a new testing. From a total of 4,207 IDUs who contacted these centers, 4,131 (98.2%) asked voluntarily for HIV-1 testing. The seroprevalence for the whole period was 48.4% (95% C.I., 46.88, 49.92). Follow-up information was available for 604 subjects of the total 2,130 subjects who were seronegative in their first visit. The incidence rate for the 1988-1992 period was 12.02/100 person-years (95% C.I., 9.62, 14.41). Prevalence showed an overall decreasing pattern with a minimum corresponding to the year 1992 (43.6%). Incidence rates increased mildly until 1990 (13.93 per 100 person-years), to stabilize beyond at approximately 10 per 100 person-years. Our incidence rates are very high regardless of the decline of prevalence. Effective risk reduction programs among IDUs have been almost nonexistent in Spain up to now and should become an immediate priority.

Adult↗