Search PubMed⌕ Search

Biomedical subjects

M Winkler

Publications and source records attributed to M Winkler.

At least 181 records · Page 10Linked to original sources
PubMed1994

Enzyme-linked immunosorbent assay for detection of immunoglobulin G antibodies to Escherichia coli Vero cytotoxin 1.

The frequency of Vero cytotoxin 1 (VT1)-neutralizing antibody (NAb) in serum specimens from 790 age-stratified (0 to 70 years) control individuals from Toronto was 61 of 790 (7.7%), with a peak of 19% in the 20- to 30-year-old age group and a second peak of 16.7% in the 60- to 70-year-old age group. A total of 568 serum specimens, including 538 from the 790 Toronto control subjects, 21 from patients from three outbreaks of VT-producing Escherichia coli (VTEC) infection, and 9 known VT1-NAb-positive serum specimens from patients with hemolytic-uremic syndrome (HUS), were then tested for the presence of anti-VT1 immunoglobulin G (IgG) by an enzyme-linked immunosorbent assay (ELISA). The mean ELISA values of 522 VT1-NAb-negative serum specimens and 46 VT1-NAb-positive serum specimens were 0.09 +/- 0.06 (range, 0 to 0.56) and 0.78 +/- 0.66 (range, 0.16 to 2.91), respectively (P < 0.001; Student's t test). With a breakpoint of 0.21 (mean ELISA value of the VT1-NAb-negative sera + 2 standard deviations), the sensitivity, specificity, positive predictive value, and negative predictive value of the VT1 IgG ELISA compared with those of the VT1-NAb assay were, respectively, 95.7, 98.7, 86.3, and 99.6%. There were nine discrepant serum specimens, of which seven were anti-VT1 IgG positive and VT1-NAb negative and two were anti-VT1 IgG negative and VT1-NAb positive. The ELISA was also used for testing 238 control serum specimens from The Netherlands, Japan, and India and acute- and convalescent-phase serum specimens from 42 Toronto patients with HUS. The frequencies of anti-VT1 IgG (with VT1-NAb frequencies in parantheses) in control sera from the Netherlands, Japan, and India were 6% (3%), 1.1% (0%), and 12% (10%), respectively, with no age clustering. The frequencies of anti-VT1 IgG seropositivity in HUS patients were 5 of 14 (35.7%) in patients with unknown toxin exposure, 2 of 22 (9.1%) in individuals with known exposure to VT1 plus VT2 or VT1 alone, and 0 of 6 (0%) in patients exposed to only VT2. Development of serum anti-VT1 IgG response appears to be the exception rather than the rule in sporadic HUS patients infected with VTEC expressing VT1. However, in two family outbreaks associated with VTEC strains expressing VT1 alone and VT1 plus VT2, respectively, the presence of anti-VT1 IgG in virtually all exposed individuals who remained symptom free suggests that the presence of antibody was associated with protection.

Adolescent↗
PubMed1994

UL69 of human cytomegalovirus, an open reading frame with homology to ICP27 of herpes simplex virus, encodes a transactivator of gene expression.

The UL69 open reading frame of human cytomegalovirus (HCMV) is homologous to the immediate-early protein ICP27 of herpes simplex virus, an essential viral regulatory protein involved in the transition from early to late gene expression. Genes with homology to ICP27 have been detected in all subclasses of herpesviruses so far. While the respective proteins in alpha- and gammaherpesviruses have been defined as trans-regulatory molecules, nothing is known about these genes in betaherpesviruses. This study was therefore undertaken in order to investigate expression from the UL69 gene locus of HCMV. Northern (RNA) blot experiments revealed a complex pattern of transcripts that changed during the time course of the HCMV replicative cycle: two transcripts of 2.7 and 3.5 kb that were regulated differentially could be detected as early as 7 h after infection. However, these transcripts could not be detected in the presence of cycloheximide. Additional, larger transcripts were present exclusively at late times after infection. To analyze protein expression from the UL69 gene region, the UL69 open reading frame was expressed as a histidine-tagged protein in Escherichia coli. A specific antiserum was generated and used to detect the UL69 protein in HCMV-infected cells which revealed its localization within the intranuclear inclusions that are characteristic for HCMV infection. In cotransfection experiments, an HCMV true late promoter could not be activated by UL69, whereas an early promoter and several heterologous promoters were stimulated about 10-fold. Complementation studies showed that the UL69 protein cannot substitute for ICP27 in the context of the HSV infection, suggesting functional differences between these two proteins. In summary, these experiments define a novel regulatory protein encoded by HCMV that is expressed as an early-late gene and appears to exert a broad stimulatory effect on gene expression.

Amino Acid Sequence↗
PubMed1994

Effects of inhaled nitric oxide on pulmonary hemodynamics and gas exchange in an ovine model of ARDS.

Inhaling low concentrations of nitric oxide (NO) gas causes selective pulmonary vasodilation of ventilated lung regions. NO activates soluble guanylate cyclase, increasing guanosine 3',5'-cyclic monophosphate (cGMP). Inhibition of NO synthesis enhances hypoxic pulmonary vasoconstriction. Therefore we examined independent and combined effects of NO inhalation and infusion of NG-nitro-L-arginine methyl ester (L-NAME), an NO synthesis inhibitor, on pulmonary vascular pressure-flow relationships, gas exchange, and plasma cGMP levels in anesthetized and mechanically ventilated sheep with acute lung injury induced by bilateral lavage. After lavage, inhaling 60 ppm by volume of NO decreased pulmonary arterial pressure (PAP) and resistance without any systemic hemodynamic effects, increased arterial PO2, and decreased venous admixture (Qva/QT; all P < 0.05) without altering cardiac output (QT), mixed venous PO2, or O2 uptake, major determinants of intrapulmonary shunt. During NO inhalation, PAP-left atrial pressure gradient (PAP-LAP) and Qva/QT were reduced (both P < 0.05) independently of QT, which was varied mechanically. L-NAME infusion produced systemic and pulmonary vasoconstriction and increased PAP-LAP gradient across the entire range of QT, whereas Qva/QT, was not changed. NO inhalation after L-NAME infusion produced pulmonary vasodilation and decreased Qva/QT to the same degree as NO inhalation alone. Five to 10 min after inhalation of 60 ppm NO, before and after L-NAME infusion, arterial plasma cGMP levels were increased by 80% (both P < 0.05). With NO breathing after L-NAME, we measured a consistent transpulmonary cGMP arteriovenous gradient [31 +/- 8 and 33 +/- 7 (SE) pmol/ml at 5 and 10 min, respectively; both P < 0.05]. NO inhalation before or after L-NAME administration in this acute lung injury model reduced Qva/QT, most likely by increasing cGMP concentration in ventilated lung regions and causing selective pulmonary vasodilation.

Administration, Inhalation↗
PubMed1994

Plasma vs whole blood for therapeutic drug monitoring of patients receiving FK 506 for immunosuppression.

By retrospective analysis of 13,000 blood samples obtained from 248 patients receiving FK 506 therapy, we compared the suitability of plasma with that of whole blood as the matrix for therapeutic drug monitoring of FK 506. The plasma concentrations did not correlate with the concentrations in whole blood (r = 0.56). In contrast to plasma samples (analyzed by enzyme immunoassay), FK 506 was detectable in all whole-blood samples (analyzed by enzyme immunoassay/microparticle enzyme immunoassay). The inter- and intraindividual variations of FK 506 measurements were greater in plasma than in whole blood. Moreover, plasma concentrations correlated only poorly with clinical events. There was a tendency to greater plasma concentrations being measured during episodes of toxicity, but no clear difference was evident between stable course and rejection. In whole-blood specimens, a correlation between reduced or increased FK 506 concentrations and rejection or toxicity, respectively, was observed. The discriminatory power of whole-blood values was greater for the differentiation between toxicity and stable course than between rejection and stable course. We therefore recommend whole blood rather than plasma as the matrix for therapeutic monitoring of FK 506 concentrations.

Drug Monitoring↗
PubMed1994

[Puerperium after threatened premature labor--positive effects of infection screening by determination of CRP in pregnancy].

Silent intrauterine infection as cause of preterm labour should be recognised early by measuring C-reactive protein (CRP) levels in the maternal serum. Ensuing antibiotic therapy may not only cause gestational prolongation, but also has a positive effect on pathology during the puerperal period. Consequently, we examined the rate of infectious puerperal complications of 181 patients who suffered from so-called idiopathic preterm labour. 84 patients showed normal CRP-levels at the onset of tocolysis (< 5 mg/l); an elevated level was found in 97 patients (> 5 mg/l). Patients with elevated CRP-levels and supplemented antibiotic therapy during pregnancy (n = 51) showed significantly fewer symptoms of postpartal endometritis than women with similarly elevated CRP-levels but without antibiotics (n = 46). This effect was not produced when preterm labour was associated with normal CRP-levels. Patients with premature contractions and elevated CRP-values at the onset of tocolysis seem to benefit from the antibiotic therapy during pregnancy because they show reduced infectious complications throughout the puerperal period.

Adult↗
PubMed1994

Human dental plaque formation on plastic films. A quantitative SEM study.

The initial colonization of bacteria in previously clean teeth or artificial surfaces inserted in mouth has been reported to occur at various periods of time. Rönström et al., using light microscopy, saw that bacteria were present 10 seconds after prophylaxis. Bacterial culture studies have shown that microorganisms associated with the surface coating on tooth surfaces appeared within minutes after prophylaxis. Furthermore, Rönström et al. noted that the number of bacteria increased over a period of four hours. In contrast, ultrastructural investigations of early plaque have demonstrated bacterial colonization only within the first two hours of plaque development in a few samples obtained on a smooth surface and in most samples on a rough surface. However, microorganisms have been found regularly after four hours of plaque accumulation in subjects with healthy gingiva. The aim of the present investigation was to determine the earliest occurrence of bacterial colonization in situ and to observe the pattern of the initial formation of human dental plaque.

Adult↗
PubMed1993

An outbreak of Corynebacterium pseudotuberculosis infection in an Israeli dairy herd.

An outbreak of Corynebacterium pseudotuberculosis infection in an Israeli dairy herd appeared in four clinical forms: cutaneous, mastitic, visceral and a mixed form. Only cows were affected and susceptibility increased with age. Most cases occurred during a short period in the summer months. The total morbidity rate was 13.7 per cent involving 41 cows. Thirty cows were affected by the cutaneous form, five by the mastitic form, four by the mastitic and cutaneous forms, one by the mastitic and visceral forms and one by the visceral form. The cutaneous form appeared as one or two pyogranulomatous lesions affecting the body or head. Subclinical to severe clinical mastitis was found in the mastitic form. In the visceral form the upper and lower respiratory system were affected by multiple purulent lymphadenitis. All the cutaneous lesions recovered irrespective of treatment. Mastitis did not respond to treatment and severely affected milk production in most cases. All the isolates of C pseudotuberculosis were nitrate reductase negative. Most isolates were sensitive to norfloxacin, cephalothin, methicillin, kanamycin and furazolidone and resistant to ampicillin, lincomycin and neomycin.

Age Factors↗
PubMed1993

Conversion from cyclosporin to FK 506 after liver transplantation.

Thirty-seven liver-grafted patients with steroid-resistant acute or chronic graft rejection or with cyclosporin-related complications were converted from CyA to FK 506. The clinical outcome of the patients primarily depended on the degree of liver dysfunction present at initiation of FK 506 treatment. In patients switched to FK 506 for treatment of acute or early chronic graft rejection, CyA nephrotoxicity, or CyA malabsorption, the FK 506 therapy was associated with a clear improvement in the clinical course. In contrast, in patients with advanced chronic graft rejection, a lower response rate to the conversion in immunosuppression was observed. The lower response rate was associated with a higher patient mortality. These studies demonstrate that FK 506 represents a valuable alternative immunosuppressant for liver-grafted patients. The conversion from CyA to FK 506 should take place before serious--and potentially irreversible--disturbances in liver function are observed.

Acute Disease↗
PubMed1993

Neck cannulation for the repair of thoracic artery aneurysms in the infant.

Thoracic aneurysms are relatively rare in infancy. We report our experience with two such patients, one with a false aneurysm of the ascending aorta and the other with a mycotic aneurysm of the main pulmonary artery. Neck cannulation prior to sternotomy, using cannulae designed for extracorporeal membrane oxygenation, allowed entry into the mediastinum under controlled circumstances and permitted the successful repair of the aneurysms.

Aneurysm, False↗