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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 469 records · Page 26Linked to original sources
PubMed1987

A model of high-affinity antibody binding to type III group B Streptococcus capsular polysaccharide.

We recently reported that the single repeating-unit pentasaccharide of type III group B Streptococcus (GBS) capsular polysaccharide is only weakly reactive with type III GBS antiserum. To further elucidate the relationship between antigen-chain length and antigenicity, tritiated oligosaccharides derived from type III capsular polysaccharide were used to generate detailed saturation binding curves with a fixed concentration of rabbit antiserum in a radioactive antigen-binding assay. A graded increase in affinity of antigen-antibody binding was seen as oligosaccharide size increased from 2.6 repeating units to 92 repeating units. These differences in affinity of antibody binding to oligosaccharides of different molecular size were confirmed by immunoprecipitation and competitive ELISA, two independent assays of antigen-antibody binding. Analysis of the saturation binding experiment indicated a difference of 300-fold in antibody-binding affinity for the largest versus the smallest tested oligosaccharides. Unexpectedly, the saturation binding values approached by the individual curves were inversely related to oligosaccharide chain length on a molar basis but equivalent on a weight basis. This observation is compatible with a model in which binding of an immunoglobulin molecule to an antigenic site on the polysaccharide facilitates subsequent binding of antibody to that antigen.

Antibodies, Bacterial↗
PubMed1987

Quantitative assessment of vaginal microflora during use of tampons of various compositions.

Although the effect of vaginal tampons on the microbial flora during menstruation has recently been studied by several investigators, quantitative effects attributable to particular tampon fibers have received less attention. The purposes of the present study were (i) to determine and then to compare the effects of polyacrylate rayon tampons and viscose rayon tampons on the normal vaginal flora, (ii) to compare quantitative bacterial counts obtained from these tampons with those obtained from concomitant vaginal swabs, and (iii) to determine whether either of these tampon types alters the vaginal microflora when compared with the microflora in the same women using all-cotton tampons or external catamenial pads. Tampon and swab samples were obtained at predetermined times from 18 women for an average of seven menstrual cycles. Samples consisting of swabs from women wearing menstrual pads were compared with swab and tampon samples taken at predetermined times during the menstrual cycle from women using cotton, polyacrylate rayon, or viscose rayon tampons. Samples were analyzed for total aerobic, facultative, and anaerobic bacterial counts. Statistical evaluation of the results indicated that, on the whole, total bacterial counts decreased during menstruation and that the numbers of bacteria in tampons tended to be lower than those in swab samples taken at the same time. The tampon type had little effect on the vaginal microflora.

Adult↗
PubMed1987

Qualitative assessment of vaginal microflora during use of tampons of various compositions.

The effect of vaginal tampons on the microbial flora during menstruation has recently been studied by several investigators. However, little information regarding the qualitative effects attributable to particular tampon fibers is available. The purpose of the present study was to compare the effects of polyacrylate rayon tampons and cotton-viscose rayon blend tampons on the qualitative bacterial counts obtained from tampons and concomitant vaginal swabs and to determine whether either of these tampon types alters the qualitative makeup of the vaginal microflora when compared with the microflora in the same women using all-cotton tampons or external catamenial pads. Tampon and swab samples were obtained as described previously (A. B. Onderdonk, G. R. Zamarchi, M. L. Rodriguez, M. L. Hirsch, A. Muñoz, and E. H. Kass, Appl. Environ. Microbiol. 53:2774-2778). The genus and species of the six dominant bacterial species in each sample were identified, if possible. A statistical evaluation of the qualitative makeup of the microflora revealed that the same numerically dominant phenotypes were present regardless of sample type, sample time, or catamenial product. Predictable changes in total numbers among the dominant species were also noted when the data were evaluated by day of menstrual cycle. The correlation between the total numbers of each dominant species present was evaluated by day of cycle, and the findings are discussed.

Adult↗
PubMed1987

A case-control study of lung cancer and diesel exhaust exposure in railroad workers.

A case-control study of deaths among U.S. railroad workers was conducted to test the hypothesis that lung cancer is associated with exposure to diesel exhaust. Employed and retired male workers with greater than or equal to 10 yr of service who were born on or after January 1, 1900 and who died between March 1, 1981 and February 28, 1982 were eligible. We collected 87% of the death certificates from 15,059 deaths reported to the U.S. Railroad Retirement Board (RRB). Cases of lung cancer (1,256) were matched to controls by age (+/- 2.5 yr) and date of death (+/- 31 days). Potential exposure to diesel exhaust was assigned based on an industrial hygiene evaluation of jobs and work areas. Each subject's work history was determined from a yearly job report filed by his employer with the RRB from 1959 until death or retirement. Asbestos exposure prior to 1959 was categorized by the job held in 1959, the end of the steam locomotive era, or by the last job held if retirement occurred before 1959. Smoking histories were obtained by questionnaire from next of kin. Using multiple conditional logistic regression analysis to adjust for smoking and asbestos exposure, workers 64 yr of age or younger at the time of death with work in a diesel exhaust exposed job for 20 yr had a significantly increased relative odds (odds ratio = 1.41, 95% Cl = 1.06, 1.88) of lung cancer. No effect of diesel exhaust exposure was seen in workers 65 yr of age or older because many of these men retired shortly after the transition to diesel-powered locomotives.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1987

Isolation of Salmonella using three selective enrichment broths from sausages naturally contaminated. Its relationship with other microorganisms that produce food toxi-infections.

Recently a great number of cases of human salmonellosis has been observed, and contaminated foods are the most important source of gastro-intestinal diseases by Salmonella. A comparative study of the efficiency of Salmonella spp. isolation from different kinds of sausage was carried out, using selenite-cystine (SC), Müller-Kauffmann tetrathionate (MK) and Rappaport-Vassiliadis (RV/43) broths. In addition, other microorganisms that produced food toxi-infections were investigated. The percentage of Salmonella detection using RV/43 broth is superior to those obtained by the MK/43 and SC/36 procedures. The first medium cited produces a higher recovery of different Salmonella strains and serotypes, and the inhibitory effects observed on the interferent competitive organisms are higher than the other broths.

Animals↗
PubMed1986

The relationship of blood lead to blood pressure in a longitudinal study of working men.

The relationship of lead exposure to blood pressure has been examined in a longitudinal study of a cohort of 89 Boston, Massachusetts, policemen. At the baseline examination, subjects had a blood lead determination and three consecutive blood pressure measurements. Triplicate blood pressure measurements were also taken at years 3, 4, and 5. Multivariate analysis revealed that, after correction for previous systolic blood pressure, body mass index, age, and smoking, a high level of blood lead was a significant predictor of subsequent elevation of systolic pressure. Bootstrap simulations of these models provided supporting evidence for the observed associations. These data suggest that lead exposure can significantly affect systolic pressure.

Blood Pressure↗
PubMed1986

Potentiation by levamisole, methisoprinol, and adenine or adenosine of the inhibitory activity of human interferon against encephalomyocarditis virus.

The antiviral action of different human interferons against encephalomyocarditis virus in HeLa cell cultures was analyzed. Cell treatment with levamisole (200 micrograms/ml), methisoprinol (1 mg/ml), or adenine or adenosine (33 or 100 micrograms/ml, respectively) potentiated the anti-encephalomyocarditis virus activity of human interferon by 8- to 32-fold. A higher level of potentiation (256-fold) was achieved either by combined treatments with levamisole plus methisoprinol or by treatment with one of these compounds plus adenine or adenosine.

Adenine↗
PubMed1986

Methods for quantitative and qualitative evaluation of vaginal microflora during menstruation.

The quantitative and qualitative changes in the bacterial flora of the vagina during menstruation have received inadequate study. Similarly, the effect of vaginal tampons on the microbial flora as well as the relationship between the microbial flora of the vagina and that of the tampon has not been adequately evaluated. The purposes of the present study were (i) to develop quantitative methods for studying the vaginal flora and the flora of tampons obtained during menstruation and (ii) to determine whether there were differences between the microflora of the tampon and that of the vaginal vault. Tampon and swab samples were obtained at various times from eight young healthy volunteers for 8 to 10 menstrual cycles. Samples consisted of swabs from women wearing menstrual pads compared with swab and tampon samples taken at various times during the menstrual cycle. Samples were analyzed for total facultative and anaerobic bacterial counts, and the six dominant bacterial species in each culture were identified. Statistical evaluation of the results indicates that total bacterial counts decreased during menstruation and that swab and tampon samples yielded similar total counts per unit weight of sample. The numbers of bacteria in tampons tended to be lower than in swabs taken at the same time. Overall, during menstruation, the concentrations of lactobacilli declined, but otherwise there was little difference among the species found during menstruation compared with those found in intermenstrual samples. Cotton tampons had little discernible effect on the microbial flora.

Adult↗
PubMed1986

A population-based case-control study of mesothelioma deaths among U.S. railroad workers.

We have completed a case-control analysis of mesothelioma deaths among current and retired U.S. railroad employees. Cause-specific death certificates were obtained for 87% of 15,059 deaths reported by the railroad retirement board, and 20 mesotheliomas were identified according to death certificate diagnosis. A 10:1 matched analysis with railroad workers dying of nonmalignant, nonaccidental causes yielded a very strong association with prior railroad work in jobs with potential asbestos exposure (odds ratio = 7.2, 95% lower confidence limit = 3.3). Consideration of railroad occupations with regular asbestos exposures (e.g., skilled trades, steam locomotive repair) yielded an odds ratio of 21.4 (95% lower confidence limit = 8.7), but the occupations with potential intermittent exposure (e.g., engineers, firemen, carmen) yielded a nonsignificant odds ratio of 2.3 (95% lower confidence limit = 0.5). Applying mesothelioma mortality rates from this study to the population of U.S. railroad workers at risk yields an estimate of 416 cases of mesothelioma occurring among U.S. railroad workers between 1981 and 2000.

Adult↗
PubMed1986

Determinants of response to eucapneic hyperventilation with cold air in a population-based study.

A population-based, epidemiologic investigation conducted in children, adolescents, and young adults analyzed the response to eucapneic hyperventilation with cold air as a continuous variable to better define factors that influence the expression of bronchial responsiveness. Among respiratory illness/symptom variables, only the report of asthma or persistent wheeze in the previous year and the report of a respiratory illness that led to activity restriction were significantly associated with response to cold air. Furthermore, a low, prechallenge FEF/FVC ratio was a significant predictor of response, especially among those subjects who reported a respiratory illness that led to activity restriction. This relationship was not observed for a low prechallenge FEF.

Adolescent↗
PubMed1986

Translocation (4;11) in ALL: a new morphologic aspect?

We have observed three patients with t(4;11)(q21;q23) among the 50 cases of ALL studied. Two were classified as L1 and the third as L3. We comment on the relationship between the morphologic classification of leukemias and the association with a t(4;11).

Bone Marrow↗
PubMed1986

Regression analysis in the presence of heterogeneous intraclass correlations.

In the statistical analysis of twinship and familial data, one often encounters the need for regression methods that control for the possibly different aggregation of the twins and the members of the families according to their type (e.g., monozygotic, dizygotic for twinship data). We present the maximum likelihood solution for the regression analysis of data in the presence of heterogeneous intraclass correlations. This work extends previous results for the case of a homogeneous intraclass correlation. An application of the methods for the analysis of twinship data is included.

Adult↗
PubMed1985

Cloning and expression of human interleukin 2 in Streptomyces lividans using the Escherichia coli consensus promoter.

Streptomyces lividans was transformed with a plasmid containing the structural gene that specifies human interleukin 2. The expression of interleukin 2 in this plasmid is controlled by both the consensus promoter and a consensus ribosome binding site characteristic of Escherichia coli. We have detected production of active human interleukin 2 in liquid cultures of the transformed Streptomyces by both, biological assay and immuno-blotting analysis.

Base Sequence↗
PubMed1985

Modification of membrane permeability during Semliki Forest virus infection.

Modification of membrane permeability has been analyzed in Semliki Forest virus (SFV)-infected cells by means of translation inhibitors not permeable to normal cells. A higher inhibition of protein synthesis in the infected cells is only observed with those antibiotics that do not easily pass the cell membrane, but not with others, permeable to cells, such as anisomycin, cycloheximide, trichodermin, etc. It does not, therefore, seem that the suggestion of M. A. Gray, K. J. Micklem, and C. A. Pasternak [Eur. J. Biochem. 135, 299-302, (1983)] that protein synthesis in virus-infected cells is more susceptible to translation inhibitors in general is correct. Both low- and high-molecular weight compounds enter the cell very early during SFV infection. This permeabilization is blocked by compounds known to increase the pH of coated vesicles, such as NH4Cl and chloroquine. Inhibition of energy production by means of N3Na and 2'-deoxyglucose also blocks this process. The optimal external pH for this early permeabilization is around 7-8. Acidic pH inhibits the entry of these impermeant antibiotics promoted by SFV. Analysis of 86Rb+ content in SFV-infected HeLa cells also indicates that a drastic decline in this cation takes place, in agreement with previous findings, but disagreeing with the previous results. A parallel between the decrease in this cation and the blockade of protein synthesis is apparent, throughout the course of infection. In addition to the early permeabilization that takes place during virus entry, increased entry of hygromycin B and alpha-sarcin also occurs in SFV-infected cells from 2 to 3 hr postinfection, but not when late viral replication is blocked by means of interferon treatment.

Ammonium Chloride↗
PubMed1985

A role for adrenaline and calmodulin in modulating cyclic AMP levels during the lactogenic cycle.

The effect on lactose production of several external modulators of intracellular cyclic AMP was studied in rat mammary gland tissue slices and explants. Adrenaline, a beta-adrenergic receptor effector, forskolin, a direct adenylate cyclase activator and fluphenazine, a calmodulin inhibitor, all produced an increase in the intracellular level of cyclic AMP and a concomitant inhibition of lactose production. These results suggest a role for adrenaline and calmodulin in modulating cyclic AMP levels in mammary tissue during the lactogenic cycle.

Animals↗