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Biomedical subjects

J Mendoza

Publications and source records attributed to J Mendoza.

At least 19 recordsLinked to original sources
PubMed1995

Growth inhibition of human cancer metastases by camptothecins in newly developed xenograft models.

Several metastatic models have been developed using clonal selection of human malignant cells metastasizing into a specific organ in NIH-I Swiss immunodeficient mice. The organs of choice were the central nervous system (CNS), targeted by metastases of malignant melanoma, and the liver, with metastases of colon adenocarcinoma. Additional models of adrenal metastases by malignant melanoma, and CNS involvement by implanted human lung squamous carcinoma or lymphoblastoid cells, are also available. Organ metastases, as well as the effects of treatment, were confirmed by autopsies and histological examination of the tissues or by a surgical inspection of the liver. The treatment end points were established as the increases in survival times of treated mice relative to placebo-treated controls. Camptothecins injected i.m. or delivered via gastrointestinal tract inhibit the growth of CNS metastases and increase the survival of treated animals. 9-Amino-20(S)-camptothecin was effective in the CNS model and in the model of liver metastases. The drug increased 3.3- and 5.7-fold the survival rates relative to untreated controls with metastases of colon adenocarcinoma to the liver, and all camptothecins were significantly more effective than 5-fluorouracil, currently a drug of choice in treatment of this disease. The xenograft models of metastases are available for studies of drug passage through the blood-brain barrier optimization of drug delivery to the liver, and for the development of new camptothecin-based treatment strategies.

Adenocarcinoma↗
PubMed1995

Sensitivity of camptothecin-resistant human leukemia cells and tumors to anticancer drugs with diverse mechanisms of action.

Human leukemia U-937 cell clones resistant to 9-nitrocamptothecin (9NC) appear after exposure to increase 9NC-concentrations. Drug resistance is irreversible, regardless of whether the 9NC-resistant (U-937/CR150) cells grow in media with or without 9NC. U-937/CR150 cells are more sensitive than wild type U-937 (U-937/wt) cells to topoisomerase II-directed drugs, amsacrine, daunorubicin, and etoposide. The mitotic inhibitor, vincristine, induces hyperdiploidy in U-937/wt, but not in U-937/CR150 cells, whereas the antimetabolites, cytarabine and methotrexate, and the nitrosourea, carmustine, elicit similar responses in both U-937/wt and U-937/CR150 cells. U-937/CR150-generated tumors in nude mice are sensitive to etoposide. The clinical implications of increased sensitivity of 9NC-resistant tumors to some anticancer drugs are discussed.

Animals↗
PubMed1994

Development of resistance to 9-nitro-camptothecin by human leukemia U-937 cells in vitro correlates with altered sensitivities to several anticancer drugs.

We have recently reported that exposure of human leukemia U-937 cells to progressively increasing concentrations of 9-nitro-camptothecin (9NC) resulted in cell sublines exhibiting various levels of resistance to 9NC. Here, we report responses of wild-type (U-937/wt) and 9NC-resistant (U-937/CR) cells to various anticancer drugs used extensively in cancer chemotherapy. U-937/CR cells were more sensitive than U-937/wt cells to several commonly used drugs of diverse origin including the topoisomerase II-directed drugs amsacrine, etoposide and daunorubicin; the vinca alkaloid vincristine; and the antimetabolite methotrexate. No responses were induced by carmustine in either cell type, whereas similar responses were induced by cytarabine. The sensitivity to the drugs was investigated by monitoring cell proliferation, by determining cell cycle perturbations assessed by flow cytometry analysis of DNA content and by microscopy of stained cells. The results in this report indicate that development of 9NC resistance by the U-937 cells is accompanied by increased sensitivities to other anticancer drugs in vitro and very likely in vivo.

Antineoplastic Agents↗
PubMed1992

Evaluation of three rapid enzyme immunoassays and cell culture for detection of respiratory syncytial virus.

Three rapid enzyme immunoassay techniques for the detection of respiratory syncytial virus antigen (Becton Dickinson Directigen RSV, Abbott RSV Testpack and Abbott RSV EIA) and cell culture were evaluated in a total of 250 nasal washings. The sensitivity and specificity were 62% and 76% respectively for Directigen, 64% and 86% for RSV Testpack, and 76% and 81% for RSV EIA, taking cell culture as the reference method. Agreement between cell culture and EIA techniques was 79% (70 positive and 128 negative results). All three EIA techniques gave positive results in 69 samples (52 positive and 17 negative in the cell culture). In 121 samples all three EIA techniques gave negative results (103 negative and 18 positive in the cell culture). Using the cell culture technique 46 strains other than respiratory syncytial virus were isolated.

Animals↗
PubMed1992

[Prevalence of antibodies against CMV in Grenada].

The prevalence of anti-CMV antibodies was studied on 1,552 serum samples by means of latex passive haemagglutination method. Of all the sera studied, 1,084 were positive (69.8%). Amongst them, 523 samples came from women and 561 from men, which represent 74.7% and 65.8%, respectively. Regarding to age, 62.3% of the positive samples were from people under 30 years and 91.3% from subjects over that age. The screening of anti-CMV antibodies is especially important in blood and organ donors, where the high percentage of positivity makes it difficult to select negative blood donations. Thus, taking into account the cost-effectiveness, and the results of this study, the search for CMV-negative blood must be exerted preferentially on the group of blood donors under 30 years of age, regardless of sex.

Adolescent↗
PubMed1992

Prevalence of asthma in a tropical city of Colombia.

Four thousand subjects from Cartagena, Colombia were surveyed in order to establish the prevalence of asthma in this city. They were considered to have asthma when they had consulted their physicians for shortness of breath accompanied with wheezing during the last year and had received asthma medications. Point and cumulative prevalence were 8.8% and 12.2%, respectively. Seventy percent of the affected population was less than 15 years old. There were no significant differences in the prevalence of asthma between sexes. Forty-five percent of asthmatic subjects had family histories of asthma. The prevalence of rhinitis was 16.4% and 30.6% of the patients with asthma. The asthma prevalence of this study is high, indicating that this respiratory disease is a significant health problem in this tropical city.

Adolescent↗
PubMed1991

[Evaluation of IgG and IgA type antibodies to capsid and early antigens of the Epstein-Barr virus in the diagnosis of nasopharyngeal carcinoma].

BACKGROUND: The Epstein-Barr virus (EBV) is related with nasopharyngeal carcinoma (NPC) in that, in this neoplasm, high levels of antibodies are found vs different EBV antigens. METHODS: The determinations of IgG and IgA type antibodies were evaluated vs capsid antigens (VCA) and early antigen (EA) of the EBV by indirect immunofluorescence in 14 patients diagnosed with NPC, in 12 patients with other tumors of the head and neck and in 61 blood donors. RESULTS: The detection of IgA type antibodies with a sensitivity and specificity of 100% and 92% for the VCA antigen and of 86% and 100% for the EA antigen are the most useful tests in the early diagnosis of nasopharyngeal carcinoma. The determination of IgG type antibodies were of a more limited usefulness with sensitivities and specificities of 86% and 67% for IgG anti-VCA and 100% and 83% of IgG anti-EA. CONCLUSIONS: The detection of antibodies vs VCA and EA antigens is useful in the differential diagnosis of NPC with other tumors of the head and neck.

Adult↗
PubMed1991

Quantitative culture of bronchoalveolar lavage from patients with anaerobic lung abscesses.

The study of anaerobic infections of the lung is usually limited to the use of invasive techniques such as transtracheal aspiration (TTA) to avoid contamination by oral flora. Bronchoalveolar lavage (BAL) has been used successfully in the study of the etiology of pneumonia in immunocompromised patients. This study evaluated the role of the quantitative culture of BAL in the diagnosis of lung abscess. Four episodes of lung abscess in three patients were studied, and the results of quantitative culture of BAL were compared with those of the standard technique of TTA. Nineteen anaerobic bacterial species were recovered from the BAL fluid, all but one at concentrations greater than 10(3) cfu/ml. Culture of BAL fluid yielded 18 of 22 of the isolates cultured from TTA, including 12 of 16 of the anaerobic bacteria. This study suggests that quantitative culture of BAL fluid may be useful in the bronchoscopic evaluation of lung abscess.

Adult↗
PubMed1991

[Etiologic diagnosis of pneumonia in adults: usefulness of bronchoalveolar lavage].

Quantitative evaluation of bacteria in bronchoalveolar lavage fluid from 15 patients with pneumonia was compared to that in 29 healthy controls. Aerobic and anaerobic cultures were used as well as cultures and staining for fungi and mycobacteria. A total of 1000 colony forming units per ml was considered a cutoff mark between colonization and infection. A positive result was obtained in 13 of 15 patients with pneumonia, allowing the identification of the causing agent. Counts below the indicated level were observed in 23 of 29 controls. There was no morbidity associated to the procedure. Thus, an 85% sensitivity and 87% specificity for bronchoalveolar lavage in the etiologic diagnosis of pneumonia may be estimated from this study.

Adult↗
PubMed1991

[Effect of the extraction of LPS (R) on the demonstration of the serological response in acute brucellosis by immunoblotting].

In order to establish the possible influence of Brucella melitensis rough strains protein extracts contamination using LPS (R) in the immunoblotting evaluation of serologic response, we have studied sera samples from 41 patients with acute brucellosis before treatment was started and also from 62 healthy individuals (control group). A whole-cell B. melitensis 115 strain extract with an without LPS (R) was used. Extraction was carried using ether-chloroform of oil-phenol. Overall, more than 50% of patients showed an antibody response (protein bands 85, 53, 50, 47, 41, 38 and 28 kD) to both antigenic products. Less than 6.4% of the control group sera showed response to any of these protein bands. There were no significant differences in the frequency of response development against these proteins using the two antigen types. However, there was some disagreement when each individual band response was compared to its homologous band.

Acute Disease↗
PubMed1991

[Evaluation of 2 serological techniques in the diagnosis of neurocysticercosis: complement fixation reaction and Western blot].

Evaluation of two serological techniques for diagnosis cysticercosis: complement fixation reaction and Western blot. Comparative study that includes 49 sera samples and 30 CSF samples belonging to 35 patients with clinical diagnosis of cysticercosis of the CNS. As a control group we used 10 sera samples of patients with Trichinella spiralis infection, 33 sera samples of patients with hydatid cyst disease, 9 sera samples from patients with oxyuriasis, 52 sera samples of healthy blood donors and 22 additional CSF samples from patients with different CNS disorders. Thirty-one samples were positive by Western blot technique and 21 samples by complement fixation reaction technique. Agreement between both techniques was 76%. Gathering clinical and laboratory information we believe that a total of 11 patients had cysticercosis of the CNS (33 samples), and three additional patients remain with indeterminate diagnosis. We have also detected cross-reactions with Western blot techniques (reactivity to more than one band) in 43% of patients with hydatid disease and in 20% of patients with Trichinella spiralis infection, but none in oxyuriasis patients. The CFR technique had cross-reaction with 33% of sera samples from hydatid disease patients and 20% of those from oxyuriasis patients. No cross-reactions were seen in any of control patients with both techniques. The two different techniques tested can be of help, together with clinical and radiology data, in the diagnosis of cysticercosis of the CNS. However, both techniques showed strong cross-reactions with hydatid disease.

Animals↗
PubMed1990

Treatment of primary pulmonary hypertension with continuous intravenous prostacyclin (epoprostenol). Results of a randomized trial.

STUDY OBJECTIVE: To determine the efficacy of continuous intravenous infusion of prostacyclin (epoprostenol) in primary pulmonary hypertension. DESIGN: Randomized trial with 8-week treatment periods and nonrandomized treatment for up to 18 months. SETTING: Four referral centers. PATIENTS: Sequential sample of 24 patients with primary pulmonary hypertension. Nineteen patients completed the study. Four patients died and one left the study because of adverse effects (pulmonary edema). INTERVENTIONS: Continuous intravenous prostacyclin administered by portable infusion pump at doses determined by acute responses during baseline catheterization in ten patients. Nine patients were treated with anticoagulants, oral vasodilators, and diuretics. MEASUREMENTS AND MAIN RESULTS: Starting with a baseline value for total pulmonary resistance of 21.6 units, there was a decrease of 7.9 units (95% CI, -13.1 to -2.2; P = 0.022) in the prostacyclin-treated group after 8 weeks; there was virtually no change in the conventional therapy group (from 20.6 to 20.4 units, not significant). Six of ten prostacyclin-treated patients who completed the 8-week study period had reductions in mean pulmonary artery pressure of greater than 10 mm Hg, whereas only one of nine in the conventional treatment group had a similar response (P = 0.057). Nine patients receiving prostacyclin for up to 18 months have persistent hemodynamic effects, although dose requirements have increased with time. Complications have been attributable to the drug delivery system. CONCLUSIONS: Prostacyclin produces substantial and sustained hemodynamic and symptomatic responses in severe primary pulmonary hypertension and may be useful in the management of some patients with this disease.

Adolescent↗
PubMed1990

Australia: perspectives in school health.

Australia, a predominantly industrialized, urban-based nation, has health problems similar to most developed countries. The federal and state relationship in Australia perpetuates a similarity between programs and practices across the country, especially in health and education. During the past decade, several research programs related to the primary prevention of Australia's major health issues were conducted. Determinations of program success have been established from these programs and their international counterparts. Guidelines and principles are discussed in the context of two recent health initiatives and are presented as indicative of current developments in Australia. For this article, a one-in-five sample of South Australian schools was surveyed regarding the health education programs and practices. Survey results and two initiatives are presented against a background of Australian health data.

Australia↗
PubMed1990

[Pattern of antibodies in acute human brucellosis defined by Western blotting].

We have evaluated with Western blotting the serologic response of 144 patients with acute brucellosis and 62 healthy controls to identify a useful antibody pattern to confirm the diagnosis of acute brucellosis. The antigen that we used was a protein extract of whole cells of the strain 115 (rough) of B. melitensis. Patients sera were obtained at the time of diagnosis and before the start of specific therapy. There was antibody response to 21 protein bands. The molecular weights (MW) and frequencies of the most significant bands were the following: 85 Kd (60.4%), 70 Kd (54.1%), 53 Kd (63.9%), 50 Kd (65.3%), 47 Kd (71.5%), 41 Kd (74.3%), 38 Kd (68.7%), 33 Kd (56.2%), 28 Kd (52.8%). At the time of diagnosis, 90.3% of the patients with acute brucellosis had antibody response to 2 or more protein bands of Mw of 47 Kd, 41 Kd, 38 Kd and 33 Kd. In none of the 62 negative control sera there was a response to more than one of the mentioned bands.

Acute Disease↗