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Biomedical subjects

M Winkler

Publications and source records attributed to M Winkler.

At least 55 records · Page 3Linked to original sources
PubMed2001

The PlA1/A2 polymorphism of platelet glycoprotein IIIa is not associated with deep venous thrombosis.

BACKGROUND: Platelet glycoprotein (GP) IIb/IIIa, a fibrinogen and von Willebrand factor binding membrane receptor, has an important role in platelet aggregation. A common leucine33-proline polymorphism (PlA1/A2) of the gene encoding the GP IIIa subunit is associated with platelet reactivity and has been proposed as a risk factor for atherothrombotic disease. The aim of this study was to investigate the role of this polymorphism for deep venous thrombosis (DVT). METHODS: We performed a case-control study including 206 patients with documented DVT and a sex- and age-matched group of 310 control subjects. GP IIIa genotypes were determined by restriction fragment analysis of amplimers containing the polymorphic site. RESULTS: A1/A1, A1/A2 and A2/A2 genotypes were found in 67.0, 31.6 and 1.5 percent of patients and 72.3, 25.8 and 1.9 percent of controls (p=0.35), PlA2 allele frequencies were 0.17 in patients and 0.15 in controls (p=0.92). Odds ratio of the PlA2 allele for DVT was 1.21 (95 percent CI 0.85-1.71, p=0.29) and remained insignificant after adjustment for factor V Leiden and prothrombin 20210A genotypes (1.22, 95 percent CI 0.86-1.75, p=0.27). CONCLUSIONS: Our data suggest that the PlA1/A2 polymorphism of GP IIIa is not associated with DVT.

Adult↗
PubMed2000

Drastic enhancement of energy-loss straggling of relativistic heavy ions due to charge-state fluctuations

Stopping power and energy-loss straggling of 197Au, 208Pb, and 209Bi projectiles have been measured in different solids (4</=Z2</=82) in the energy range (100-1000) MeV/u. The experimental results clearly demonstrate the influence of the different charge states of the ions. Because of charge-state fluctuations the energy-loss straggling is up to 7 times larger than the pure collisional straggling. The selected energy domain in combination with the heavy projectiles allows for the first time an unambiguous interpretation of the long-standing problem of charge-changing collisions in energy-loss straggling.

Journal Article↗
PubMed2000

Influence of cold ischemia time, pretransplant anti-porcine antibodies, and donor/recipient size matching on hyperacute graft rejection after discordant porcine to cynomolgus kidney transplantation.

Organs transplanted between phylogenetically disparate species, such as from the pig into the primate, are subject to hyperacute rejection (HAR). This form of xenograft rejection is mediated by preformed natural antibodies and is believed to occur invariably in discordant xenografts thus leading to rapid destruction and complete thrombosis of the graft. Recent data, however, have shown that in the porcine to cynomolgus monkey setting, HAR is not inevitably seen after porcine kidney transplantation. The influence of preoperative antiporcine antibody levels in the recipient, cold ischemia time, and donor organ weight on the onset of HAR was investigated by using unmodified large white pigs (aged 3-12 weeks) as organ donors and adult cynomolgus monkeys (aged 1.5-3.5 years) as recipients. Porcine kidney xenotransplantation was performed in either a non-life-supporting model (n=7) or in a life-supporting model (n=8). In both models, no correlation was found between cold ischemia time and HAR. When preoperative anti-porcine antibody levels were investigated, a significant increase in incidence of HAR was observed in animals with elevated anti-porcine IgM (P<0.05) but not IgG levels (P=NS). Interestingly, although 5 of 12 grafts with an organ weight of less than 50 g underwent HAR, none of three grafts with a donor organ weight of more than 70 g showed signs of HAR. In addition, all three larger grafts showed intraoperative and postoperative urine production, although only in 1 (48 g) of the 12 grafts weighing less than 50 g primary graft function was observed. In one animal, a second porcine kidney (23 g) was successfully transplanted (without HAR) immediately after HAR and subsequent removal of a first porcine kidney (20 g). These results indicate that in the porcine to cynomolgus monkey setting anti-porcine IgM rather than IgG anti-porcine antibody levels seem to be of predominant importance for the induction of HAR. By increasing the donor organ size and weight the frequency of the onset of HAR can be at least reduced. This is most likely due to immunoabsorption of the recipients preformed antibodies in the porcine kidney without lethal damage for the graft.

Acute Disease↗
PubMed2000

Solid-phase microextraction-gas chromatography-mass spectrometry of biologically active substances in water samples.

A solid-phase microextraction (SPME) method for determining trace amounts of polar, biologically active substances in water systems was developed and compared with solid-phase extraction followed by derivatization and GC-MS. SPME was examined with respect to the simultaneous determination of pharmaceuticals such as ibuprofen, paracetamol, phenazone, carbamazepine, and nonylphenols known to be xenoestrogens. The extraction performance of different SPME fibre coatings was studied. Coatings like polyacrylate and Carbowax-divinylbenzene proved to be the best suited. The optimum extraction time was found to be 30 min and the detection limits were between 0.2 and 50 microg/l. Low concentrations of accompanying organic matter did not impair these limits. One of the main pharmaceutical contaminants found in ground and river water around Leipzig (Germany) was ibuprofen, with a concentration in the ng/l range. The enantioselective metabolism of ibuprofen was investigated.

Estrogens↗
PubMed2000

Two-year clinical performance of two primer adhesives on class V restorations.

The prime purpose of this clinical trial was to examine the clinical quality and retention rate of resin composite in connection with two recently developed acetone-based primer adhesives in Class V lesions according to ADA Clinical Protocol Guidelines for Dentin and Enamel Adhesive Materials. All cavities were nonretentive and predominantly in dentin (mixed Class V lesions). Total bonding was not limited either by sub-base or by base materials. All the trial restorations were placed under rubber dam. Group 1 (Version 16-135-1) and group 2 (Version 17-17-1) consisted of 42 patients with 46 trials and 38 patients with 43 fillings, respectively. The mean follow-up period and the recall response at the end of the study of group 1 were 22.8 months and 92.9% and of group 2 were 22.4 months and 94.7%. The trial restorations of both groups maintained their predominantly rated USPHS-Code Alpha level within the follow-up period. The cumulative failure rate of two trials in group 1 and four in group 2 determined a failure percentage of 4.4% and 9.3%, respectively, which is within the ADA-18 month limit of <10% Charlie. The Version KL 16-135-1 came into the market as Prime & Bond(R) 2.1, and the other one turned out to be Dyract Adhesive(R) PSA, which was primarily introduced as a single-component adhesive for compomer restorative Dyract(R) (Dentsply DeTrey, Germany).

Acetone↗
PubMed2000

Induction of labor by prostaglandin E(2) in relation to the Bishop score.

OBJECTIVE: To compare the effectiveness of prostaglandin E(2) intravaginal gel with the intracervical gel in patients with an unfavorable cervix. METHOD: In a prospective multicenter trial 470 patients with unfavorable Bishop scores (3-4) were randomized to receive prostaglandin vaginal gel (2 mg) or intracervical gel (0.5 mg). RESULTS: In patients with unfavorable Bishop scores the intravaginal application route resulted in a better cervical ripening, a shorter induction to delivery interval and a higher cumulative rate of deliveries during 24 h (P=0.01). CONCLUSION: Intravaginal instillation of prostaglandin E(2) gel for induction of labor is effective in patients with an unfavorable Bishop score of 3-4.

Administration, Intravaginal↗
PubMed2000

Optimization of solid-phase microextraction for the gas chromatographic-mass spectrometric determination of synthetic musk fragrances in water samples.

Described is a solid-phase microextraction-gas chromatography-mass spectrometric procedure for the determination of three polycyclic musk fragrances (galaxolide, tonalide, celestolide) and a nitro musk fragrance (musk ketone) in natural river water. Both classes of the musk fragrances could be extracted reproducibly from water samples with a recovery in the range of 45-50% and relative standard deviation of 11-18% for fragrances at 25-260 ng/l levels. Detection limits were between 14 and 22 ng/l. To achieve this reproducibility it was necessary to use an internal standard, pentachloronitrobenzene, for all substances. Best recoveries were achieved with polydimethylsiloxane (PDMS)-divinylbenzene fibers (compared to recoveries obtained with PDMS, polyacrylate or carboxen fibers) and extraction times of 45 min at 30 degrees C, with no need for attainment of equilibrium conditions. The latter was achieved at about 2 h. For Elbe River water, in the vicinity of Magdeburg, no matrix effects were observed. While the average levels of celestolide and musk ketone for samples investigated were below the detection limits, 14 and 22 ng/l, respectively, and for tonalide below the limit of quantification, 22 ng/l, the ambient levels of galaxolide in the Elbe River were 117 ng/l.

Fatty Acids, Monounsaturated↗
PubMed2000

Tissue concentrations of endothelial cell adhesion molecules in the lower uterine segment during term parturition.

OBJECTIVE: To determine the concentration of endothelial cell adhesion molecules in the lower uterine segment during parturition at term. METHODS: We analyzed protein extracts from the lower uterine segments of 38 women who had nonelective cesareans at term. We measured concentrations of intercellular adhesion molecule-1, endothelial leukocyte adhesion molecule-1, vascular cell adhesion molecule-1, and platelet endothelial cell adhesion molecule-1 by enzyme-linked immunosorbent assay. Subjects were grouped according to cervical dilatation (less than 2 cm, n = 10; 2 to less than 4 cm, n = 9; 4-6 cm, n = 9; more than 6 cm, n = 10) and duration of labor (up to 6 hours, n = 14; 6-12 hours, n = 10; 12-24 hours, n = 9; longer than 24 hours, n = 5) at the time of cesarean. RESULTS: The median concentration of intercellular adhesion molecule-1 increased significantly with increasing dilatation (from 2.24 ng/mg total protein at less than 2 cm to 6.73 ng/mg at 4-6 cm) and increasing duration of labor (from 2.53 ng/mg up to 6 hours to 5.90 ng/mg at 12-24 hours). However, this study did not have adequate statistical power to identify differences in concentrations of the other endothelial adhesion molecules. CONCLUSION: The results indicate that parturition at term is associated with expression of intercellular adhesion molecule-1.

Adult↗
PubMed2000

Regulation of interleukin-8 synthesis in human lower uterine segment fibroblasts by cytokines and growth factors.

OBJECTIVE: To investigate the influence of lipopolysaccharide, cytokines, growth factors, and progesterone on the synthesis of interleukin-8 by human lower uterine segment fibroblasts. METHODS: Fibroblasts derived from a lower uterine segment biopsy specimen obtained from a woman undergoing elective cesarean delivery at term were exposed to lipopolysaccharide, interleukin-1beta, transforming growth factor-beta(1), platelet-derived growth factor-AB, and combinations of these substances. All experiments were performed in the absence and presence of progesterone. The concentration of interleukin-8 in the culture medium was determined by enzyme immunoassay after 24 hours. RESULTS: Compared with controls (0.71 +/- 0.04 ng interleukin-8/10(6) cells), fibroblasts exposed to lipopolysaccharide, transforming growth factor-beta(1), or platelet-derived growth factor-AB exhibited no increase, or at most, only a minor but significant increase, in interleukin-8 secretion. Incubation with interleukin-1beta led to a moderate increase, whereas the combinations interleukin-1beta/transforming growth factor-beta(1) (105.0 +/- 7.5 ng interleukin-8/10(6) cells) and interleukin-1beta/platelet-derived growth factor-AB (387.3 +/- 25.6 ng interleukin-8/10(6) cells) increased interleukin-8 secretion dramatically. No further increase was observed with the combination interleukin-1beta/platelet-derived growth factor-AB/transforming growth factor-beta(1). When progesterone was added, interleukin-8 secretion decreased significantly by 16-34%, depending on the stimulator, or did not change. CONCLUSION: The findings indicate that interleukin-8 secretion by human lower uterine segment fibroblasts in vitro is upregulated by interleukin-1beta, transforming growth factor-beta(1), and platelet-derived growth factor-AB in a synergistic fashion. Because interleukin-8 mediates the invasion of neutrophils into the cervical stroma, this may be an important mechanism controlling cervical dilatation during parturition.

Adult↗