Biomedical subjects
I Herrera
Publications and source records attributed to I Herrera.
Effect of maternal rotavirus immunization on milk and serum antibody titers.
This prospective study evaluated human milk and serum antirotavirus antibody concentrations following maternal rotavirus immunization. Postpartum women (33) were randomized into 3 groups and received a single oral dose of rhesus rotavirus monovalent reassortant vaccine (10(4) pfu), tetravalent vaccine (10(4) pfu), or placebo. Milk (secretory [s] IgA) and serum (IgA and IgG) specimens were tested for antirotavirus isotype-specific antibody. Sera also were tested for G1- to G4-specific antibody. Prevaccine milk and serum isotype-specific antibody concentrations were not significantly different in the 3 groups. Postvaccine sIgA log titers were significantly greater in the 2 vaccine groups than the placebo group (P = .002). Mean log10 titers at 1 week were 2.1 (95% confidence interval [CI], 2.0-2.3) in the 2 vaccine groups and 1.7 (95% CI, 1.5-1.9) in the placebo group. Milk titers did not differ between vaccine groups. There was no difference in reactogenicity between groups. The significantly higher milk concentrations of antibody to rotavirus in postpartum women who received rotavirus immunization persisted for 4 months.
Enhanced susceptibility of Staphylococcus aureus pretreated with cefepime and cefpodoxime to leukocyte activity.
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Rufloxacin enhances susceptibility of Escherichia coli to leukocyte activity.
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[Isolation, sequencing and ultrastructure of HTLV-I and HTLV-II retroviruses. Presence of the HTLV-II subtype b among Spanish intravenous drug addicts].
BACKGROUND: Six cases of HTLV-I/II infection were selected for isolation and characterization of these retrovirus. METHODS: Detection of anti-HTLV antibodies was carried out by enzyme immunoassay (EIA), immunofluorescence (IFI), and Western blot (WB). Analysis of proviral DNA was performed by PCR. Viral culture and partial sequencing of the pol and pX genes were carried out. Electron microscopy morphologically characterized the viral particles. RESULTS: Serologic study demonstrated four cases of HTLV-II, one of HTLV-I, and one non-typeable HTLV infections. This last case was confirmed as positive for HTLV-II by PCR. Five new HTLV-II and one HTLV-I infected cell lines have been established by co-culture. Electron microscopy allowed morphologic characterization of the viral particles found in the infected cells. The sequence of the five strains of HTLV-II was identical demonstrating a divergence of 0.49% in the pX region and of 4.5% in the pol region compared with the HTLV-II Mo prototype. Comparison of these sequences with those corresponding to different strains of HTLV-II isolates from American Indians (subtypes b) suggest that these Spanish strains are more closely related with the subtype b than with the subtype a (HTLV-II Mo). Genetic variability study did not reveal any change in the sequence of these stains suggesting that the variability of these retroviruses in very infrequent in the regions studied. The analysis of the pol region of the HTLV-I strain demonstrated a divergence of 3.4% with respect to the sequence of the ATK-1 prototype (Japan) and of 1.7% of the strain HS-35 (Caribbean) showing a greater relation with the Caribbean strains than with those from Japan. CONCLUSIONS: The presence of HTLV-II subtype has been confirmed among intravenous drug addicts in Spain. Isolation and characterization of the HTLV-I strain demonstrated that this also circulating around Spain despite its South American origin.
Fecal antibody responses to symptomatic and asymptomatic rotavirus infections.
The role of anti-rotavirus fecal IgA (RVflgA) in protecting children against natural rotavirus infections is unclear. Rotavirus outbreaks occurred in each of four day care centers attended by 129 children; 42% of the infections were asymptomatic. RVflgA titers were measured by EIA before infection and 4 weeks later in 50 children who excreted rotavirus (excretors) and in two samples 4 weeks apart from 50 children without detected virus excretion (nonexcretors). Forty-three (86%) excretors and 18 (36%) nonexcretors had a fourfold or greater RVflgA titer rise. Preexposure RVflgA titers were higher in not infected than symptomatic (P = .002), asymptomatic than symptomatic (P = .036), and not infected than asymptomatic children (P = .07). RVflgA titers after asymptomatic infections were slightly than after symptomatic infections (P = .087). In summary, higher RVflgA titers were associated with protection against infection and illness and increased fourfold or more in both asymptomatic and symptomatic children.
[Effect of ciprofloxacin on the phagocytosis of Escherichia coli by human polymorphonuclear leukocytes].
BACKGROUND: Brief exposure of bacteria to high concentrations of some antimicrobials enhanced their susceptibility to phagocytic killing by human polymorphonuclear leucocytes. This effect was defined as Post Antibiotic Leukocyte Enhancement or PALE. In this study we have investigated the effect of prior exposure of E. coli for ten minutes to 0.99 mg/l of ciprofloxacin and 0.40 mg/l of meropenem. METHODS AND RESULTS: The pretreated bacteria were incubated for three hours in a mixture containing leukocytes and leukocytes plus serum (10% v/v). Leukocytes were prepared from blood of healthful volunteers and were extracting with ammonium chloride and differential centrifugation. At one hour intervals, aliquots were taken and added to basic water to dispute leukocytes and spread onto agar plates. Viable bacteria were counted. PALE of ciprofloxacin was higher than meropenem. CONCLUSION: Whether PALE is confirmed, it must be taken into consideration in dosage schedules.
Nonenzymatic glycosylation of hemoglobin and total plasmatic proteins in end-stage renal disease.
In order to ascertain whether there are abnormalities of nonenzymatic glycosylation in uremia, the levels of nonenzymatically glycosylated hemoglobin (GHb), and total plasmatic glycosylated proteins (PGP) were studied using the thiobarbituric acid (TBA) method, a procedure not interfered with by carbamylation. Total hemoglobin A1 (HbA1) and the A1c fraction were also determined by ion exchange chromatographic methods. Sixty-six end-stage renal disease patients (29 nondiabetic and 8 diabetic uremic patients on conservative treatment, 29 nondiabetic hemodialysis patients) and 56 controls (32 nonuremic diabetic patients and 24 healthy controls) were studied. High levels of GHb and total PGP were found in the nondiabetic uremic group on conservative treatment with all the methods used, but the persistence of high chromatographically determined HbA1 levels in hemodialysis patients contrasts with the results obtained with the other techniques, which showed lower values on hemodialysis. Nondiabetic uremic patients with abnormal oral glucose tolerance curves had significantly higher levels of TBA-determined GHb and PGP. Uremic diabetic patients had the highest glycosylation levels of all the studied groups. We conclude that there is an abnormal nonenzymatic glycosylation of proteins in uremia, independent of carbamylation reactions and partially corrected by hemodialysis.
[Milker's nodes: transmission by fomites and virological identification].
We report a case of milker's nodules in a male who was not a professional cattle raiser with indirect and accidental transmission by fomites. A parapoxvirus was demonstrated from cutaneous lesions by electron microscopy with negative stain.
Comparative study of different methods for measuring blood cyclosporine A levels in kidney transplantation.
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[Bacterial localization in apical cementum at the epithelial insertion using scanning electron microscopy].
Extracted teeth due to consequence of chronic periodontitis of adult are fractured and the apical cementum to junction epithelium is examined under S.E.M. (scanning electron microscopy) being found bacterias forms inside niches of the apical cementum.
[Acute hepatitis in childhood. Study of 96 cases and 1-year follow-up].
Authors studied 96 children, 56 boys and 40 girls, aged 1 to 16 years, with acute viral hepatitis. 53 patients were diagnosed of hepatitis a virus (HAV) detecting antibodies to HAV of the IgM class; 11 patients were diagnosed of hepatitis B virus (HBV) detecting serologic markers; 32 patients were diagnosed of non A-non B hepatitis. There were no serologic evidence of infection with cytomegalovirus and Epstein-barr virus. They report an analytical and clinical comparative study of acute viral hepatitis, and their evolution during a year, not finding any significative statistic difference. Two patients with HBV remained chronically infected.
Framework for biorthogonal Fourier series.
Biorthogonal Fourier series occur when applying separation of variables to many problems. Here an approach which possesses considerable advantages with respect to the standard one is explained.
Boundary methods: A criterion for completeness.
The application of methods which constitute an alternative to boundary integral equations to specific problems depends on development of complete systems of solutions, convergence of approximating procedures, and formulation of variational principles. This paper establishes a criterion for completeness. In this manner, greater flexibility of the theory is achieved; for example, systems of functions which are complete for different types of boundary conditions are developed.
[Effects of carbon tetrachloride on liver lipids (author's transl)].
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Connectivity as an alternative to boundary integral equations: Construction of bases.
In previous papers Herrera developed a theory of connectivity that is applicable to the problem of connecting solutions defined in different regions, which occurs when solving partial differential equations and many problems of mechanics. In this paper we explain how complete connectivity conditions can be used to replace boundary integral equations in many situations. We show that completeness is satisfied not only in steady-state problems such as potential, reduced wave equation and static and quasi-static elasticity, but also in time-dependent problems such as heat and wave equations and dynamical elasticity. A method to obtain bases of connectivity conditions, which are independent of the regions considered, is also presented.
Theory of connectivity for formally symmetric operators.
A previous paper introduced the notion of complete connectivity conditions and developed variational principles for diffraction problems subjected to such restrictions. Here, an abstract definition of formally symmetric operators is given and it is shown that the problem of connecting solutions of equations associated with this kind of operators leads to complete connectivity conditions. The variational principles previously developed as well as a present more general one are thus applicable. The problem of connecting solutions defined in different regions is basic for finite element formulations. Formally symmetric operators occur in many branches of science and engineering. Applications are given here to potential theory, wave propagation, elasticity, and a general class of boundary integral equations.
General variational principles applicable to the hybrid element method.
Functional valued operators are used to formulate diffraction problems in a general abstract form. Variational principles for this formulation are developed. They are then applied to derive results on the linearized theory of free surface flows previously reported. Applications are also made to potential theory and elasticity.