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Biomedical subjects

A Muñoz

Publications and source records attributed to A Muñoz.

At least 505 records · Page 28Linked to original sources
PubMed1983

Effect of interferon treatment on blockade of protein synthesis induced by poliovirus infection.

Treatment of HeLa cells with lymphoblastoid interferon leads to a drastic inhibition of infective poliovirus. Even relatively high concentrations of human lymphoblastoid interferon HuIFN-alpha (Ly) (400 IU/ml) do not prevent destruction of the cell monolayer after most of the cells have been infected with poliovirus. Analysis of macromolecular synthesis in a single step growth cycle of poliovirus in interferon-treated cells detected no viral protein synthesis. In spite of this inhibition of viral translation, the shut-off of host protein synthesis in interferon-treated cells is apparent when they are infected both at low and high multiplicities. Although viral RNA synthesis is inhibited considerably in cells treated with interferon, a certain amount is detected, suggesting that some viral replication takes place. Analysis of membrane permeability after poliovirus infection shows a leakage to 86Rb+ ions and modification of membrane permeability to the translation inhibitor hygromycin B at the moment when the bulk of virus protein synthesis occurs. These changes are delayed and even prevented if cells are pretreated with interferon. A situation is described in which host protein synthesis is shut-down with no major changes in membrane permeability, as studied by the two tests mentioned above. Prevention of viral gene expression by inactivation with ultraviolet light of the input virus or by treatment with cycloheximide blocks the shut-off of protein synthesis. This does not occur in the presence of 3 mM guanidine. These observations are in agreement with the idea that some poliovirus protein synthesis takes place in interferon-treated cells and this early gene expression is necessary to block cellular protein synthesis.

Cell Membrane Permeability↗
PubMed1983

Longitudinal study of the effects of maternal smoking on pulmonary function in children.

We investigated the effects of maternal cigarette smoking on pulmonary function in a cohort of children and adolescents observed prospectively for seven years. A multivariate analysis revealed that after correction for previous forced expiratory volume in one second (FEV1), age, height, change in height, and cigarette smoking in the child, or adolescent, maternal cigarette smoking significantly lowered the expected average annual increase in FEV1 (P = 0.015). On the basis of this analysis, it is estimated that if two children have the same initial FEV1, age, height, increase in height, and personal cigarette-smoking history, but the mother of one has smoked throughout the child's life whereas the mother of the other has not, the difference in the change in FEV1 over time in the exposed child, as compared with that in the unexposed child, will be approximately 28, 51, and 101 ml after one, two, and five years, respectively, or a reduction of 10.7, 9.5, and 7.0 per cent, respectively, in the expected increase. These results suggest that passive exposure to maternal cigarette smoke may have important effects on the development of pulmonary function in children.

Adolescent↗
PubMed1983

Cellular RNA is not degraded in interferon-treated HeLa cells after poliovirus infection.

A drastic inhibition of protein synthesis occurs in HeLa cells treated with human lymphoblastoid interferon and infected with poliovirus. At the time when this inhibition has been established no degradation of 32P-labelled ribosomal RNA can be detected. Isolation of the mRNAs from poliovirus-infected cells plus or minus interferon treatment, followed by translation in a reticulocyte lysate indicates that cellular mRNAs remain active. These results suggest that gross degradation of cellular RNA does not occur in interferon-treated poliovirus-infected HeLa cells and that a non-specific nuclease induced by 2'-5' A is not responsible for the inhibition of protein synthesis observed.

Cell Transformation, Viral↗
PubMed1983

Benefit-cost analysis of antimicrobial prophylaxis in abdominal and vaginal hysterectomy.

We performed a benefit-cost analysis of antimicrobial prophylaxis for hysterectomy using data from a randomized, placebo-controlled clinical trial of the efficacy of three doses of cefazolin sodium. The excess cost per patient with either operative site or urinary tract infection, or febrile morbidity diagnosed during hospitalization, was +1,777 for vaginal and +716 for abdominal hysterectomy. In patients undergoing vaginal hysterectomy, prophylactic cefazolin reduced in-hospital infectious morbidity from 52% to 23% (preventive fraction, 56%), resulting in an average net benefit of +492 per patient. In abdominal hysterectomy, cefazolin decreased in-hospital morbidity from 43% to 25% (preventive fraction, 42%), resulting in an average net savings of +102 per patient. These benefits would be eroded by use of newer, more expensive cephalosporins unless they were considerably more effective than cefazolin. The benefits also would be diminished by inappropriate prolongation of the duration of prophylaxis.

Cefazolin↗
PubMed1983

Spirometry in children. Methodology for obtaining optimal results for clinical and epidemiologic studies.

Spirometric methodology for clinical and epidemiologic use in children was evaluated in 123 third and fourth grade school children 8 and 9 yr of age. They performed spirometric testing in the middle of October and again in the middle of November 1979. The results demonstrated that spirometric standards developed from adult studies can be applied to children. In addition, a minimum of 5 and a maximum of 8 maneuvers should be attempted to provide at least 3 acceptable tracings. In children, the allowable difference between the 2 best acceptable tracings of 5% or 100 ml, whichever is greater, was demonstrated to be a reasonable guideline. The results are equally reproducible when the maximal values, the mean of the 2 or 3 best values, or the values from the "best sum" tracing (the tracing with the highest value for the sum of the FVC and FEV1) are used.

Child↗
PubMed1983

Enhancement of susceptibility of HSV-1-infected cells to natural killer lysis by interferon.

The effect of interferon (IFN) on the natural killer (NK) activity of human PBL against HSV-1-infected HeLa cells was studied. Human PBL from several individuals did not consistently show a preferential lysis of HSV-1-, vaccinia-, or adenovirus type 5-infected cells with respect to uninfected HeLa cells. Treatment with IFN of effector PBL increased their lytic activity but did not alter the degree of preference on the lysis of the target cells shown by untreated PBL. Pretreatment with IFN of HSV-1-infected HeLa cells increased their susceptibility to lysis 5- to 10-fold. In contrast, identical pretreatment of the uninfected, adenovirus type 5- or vaccinia virus-infected HeLa cells before the assay decreased their susceptibility to NK lysis. This effect was not likely to be due to a block of the viral replication because other inhibitors like mitomycin C did not have the same effect. All target cells induced IFN synthesis in effector PBL cells. A similar level of IFN was induced by HSV-1-infected or uninfected HeLa cells. Pretreatment with IFN of HSV-1-infected, but not uninfected, HeLa cells induced 5 to 10 times more IFN by PBL, in good correlation with the increase in lytic activity. PBL treated with IFN, however, in conditions to give maximal stimulation of NK activity, presented the same preferential lysis of HSV-1-infected HeLa cells and synthesized similar levels of IFN as untreated PBL. In addition, HSV-1-infected HeLa cells were killed through different target structures than uninfected cells. Taken together, our results indicate an effect of IFN at the level of the NK target structures in HSV-1-infected HeLa cells by increasing either their number or, more likely, their affinity for NK cells independent of the effect of IFN in the effector cells or as an antiviral agent.

Cytotoxicity, Immunologic↗
PubMed1983

Enzyme-linked immunosorbent assay for the detection of antibody to Chlamydia trachomatis and Chlamydia psittaci.

An enzyme-linked immunosorbent assay (ELISA) was developed with use of a strain of Chlamydia trachomatis, lymphogranuloma venereum serotype 2. The ELISA reactions were monitored by absorbance at 492 nm in a spectrophotometer. A positive control method based on one serum dilution was used to assign ELISA titers to the sera. Sera that had been tested with use of complement fixation (CF) and microimmunofluorescence (MIF) tests were examined with ELISA. ELISA was more sensitive than the CF test and as sensitive as the MIF test. Serum pairs that had diagnostic titer rises in the other tests also had such rises in ELISA. ELISA is a simple, sensitive assay for detection of antibody to C. trachomatis.

Antibodies, Bacterial↗
PubMed1983

[Physical growth during adolescence].

Authors review principal manifestations of physical growth in adolescence: adolescent growth spur, body composition and chemical maturation. A cross-sectional study performed in Madrid area (92 females and 113 males normal adolescents) showed that serum alkaline phosphatase concentrations and urinary total hydroxyproline excretion had a close relation with height velocity and sex maturity ratings in adolescents. Factorial analysis showed variable correlation between 43 anthropometric and biochemical parameters.

Adolescent↗
PubMed1982

Risk factors for infection at the operative site after abdominal or vaginal hysterectomy.

We studied risk factors for postoperative infections at the operative site after hysterectomies. Data were collected prospectively on all women undergoing vaginal hysterectomies (323 patients) or abdominal hysterectomies (1125 patients) at the Boston Hospital for Women between February 1976 and April 1978. Logistic-regression analysis indicated that factors significantly associated (P less than 0.05) with a higher risk of infection at the operative site were increased duration of operation, lack of antibiotic prophylaxis, younger age, being a clinic patient, and an abdominal approach. After these variables were accounted for, the variables of obesity, preoperative functional and anatomical diagnoses, postoperative anatomical and pathological diagnoses, estimated blood loss, menopausal status, and operation by a specific surgeon did not add predictive power. An increasing duration of operation was associated with a decreasing effect of antibiotic prophylaxis, the preventive fraction of which diminished from 80 per cent at one hour to an unmeasurable effect at 3.3 hours.

Adult↗
PubMed1982

Randomized clinical trial of perioperative cefoxitin in preventing maternal infection after primary cesarean section.

To determine the efficacy of perioperative cefoxitin in preventing infections after primary cesarean section, a randomized placebo-controlled, double-blind clinical trial was performed. Among 266 participants, those who received three perioperative 2 gm doses of cefoxitin (138) had significantly fewer serious infections (19.5% vs. 4.3%), fewer urinary tract infections (10.7% vs. 4.4%), less standard febrile morbidity (9.4% vs. 3.6%), and fewer courses of antibiotics postoperatively (23.4% vs. 11.6%). There was no reduction in the length of hospitalization. Use of perioperative cefoxitin umbilical cord is clamped are safe and efficacious in preventing infection after primary cesarean section.

Cefoxitin↗
PubMed1981

[Fever of unknown origin with a prolonged course (author's transl)].

Out of 110 cases of fever of unknown origin (FUO) that met Petersdorf and Beeson's criteria 15 patients were selected because of prolonged FUO with more than six months elapsed between admission and the final diagnosis. In this group of chronic FUO an etiological diagnosis was reached in 11 cases, distributed as follows: four cases with infections (two with toxoplasmosis, one with brucellosis, and another with a brain abscess); one with colon carcinoma; two with collagen-vascular diseases (systemic lupus erythematosus, temporal arteritis); and four with different diseases (two with familial mediterranean fever, one with idiopathic granulomatous disease, and another with factitious fever). In four cases no cause for the FUO could be determined. The procedures used to obtain the diagnosis were non-invasive in five cases (clinical course and serological tests), and invasive in another five (angiography, biopsies, and exploratory laparotomy). In one case the ethology could only be ascertained at autopsy. In the FUO with a prolonged course the peculiar etiological spectrum, the lesser yield of invasive procedures, and a mortality inferior to that of FUO in general all deserve special emphasis.

Adenocarcinoma↗
PubMed1981

Protein synthesis and membrane integrity in interferon-treated HeLa cells infected with encephalomyocarditis virus.

The survival of interferon (IFN)-treated cells after encephalomyocarditis (EMC) virus infection depends on both the concentration of interferon and the multiplicity of infection (m.o.i.) used. The cell survived EMC infection if a high IFN/m.o.i. ratio was used in the experiment, whereas cell death took place at low IFN/m.o.i. ratios, even if IFN is also present during infection. Analysis by polyacrylamide gel electrophoresis of the proteins synthesized in IFN-treated cells subsequently infected with EMC indicated that no virus proteins were detected at either low or high multiplicities of infection. However, at low m.o.i. the cell survived and continued synthesizing cellular proteins exclusively, whereas at high m.o.i. a drastic shut-off of host protein synthesis took place. Virus which had been inactivated by u.v. irradiation was unable to cause the shut-off of host protein synthesis, either in control or in IFN-treated cells. This result suggests that some virus gene expression occurs in cells treated with IFN, although no virus protein synthesis was detected. The synthesis of virus RNA was also strongly inhibited after treated of cells with IFN. The integrity of the cell membrane in control and in IFN-treated cells was studied by analysing the 86Rb+ ion leakage, the thymidine pool, the chronic uptake and the entry of the translation inhibitor hygromycin B, to which cells are impermeable, at different times after EMC infection. The results obtained indicate that the early membrane leakiness observed after virus infection is not prevented by IFN treatment. However, the development of late leakiness to 86Rb+ ions, thymidine and hygromycin B was not observed in IFN-treated cells.

Cell Membrane↗
PubMed1981

Reversal by hypotonic medium of the antiviral state induced by lymphoblastoid interferon in human HeLa cells.

The induction kinetics of the antiviral state in HeLa cells treated with human lymphoblastoid interferon (IFN) was studied. In cells treated with 4-200 U/ml IFN, the antiviral state was fully established in 7-9 h. Inhibition of virus multiplication was more rapid if the concentration of IFN was increased to 1,000 U/ml. This antiviral state gradually disappeared during the 48 h after IFN removal. Several compounds known to act on the cell membrane or on the cytoskeleton were tested for their influence on the establishment and reversal of the antiviral state. None of them were found to influence these two parameters to a significant extent. In contrast, placing HeLa cells in medium lacking NaCl partially reversed the blockade to virus multiplication induced by IFN treatment. Cells treated with IFN and later placed in hypotonic medium synthesized virus proteins after encephalomyocarditis virus infection, although at a reduced level compared to cells that had not been treated with IFN.

Alkaloids↗