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Biomedical subjects

H Metzner

Publications and source records attributed to H Metzner.

At least 19 recordsLinked to original sources
PubMed2003

Fibrin sealants in supporting surgical techniques: strength in factor XIII.

Factor XIII has a well-established role in natural coagulation and clot stabilization. It is often added back to fibrin sealants that are used in a wide range of surgical settings to achieve successful hemostasis, tissue adhesion and wound healing. Factor XIII is the final enzyme to be activated in the blood coagulation cascade. It plays an important role in maintaining the balance between coagulation and fibrinolysis. Factor XIII facilitates the formation of covalent cross-links within the fibrin network, forming a loose mesh after activation by thrombin. It adds significant resilience to fibrin clots, augmenting strength by as much as 5-fold. Both fibrin cross-linking and the factor XIII-catalyzed ligation of the fibrinolysis inhibitor alpha(2)-antiplasmin to the fibrin clot contribute to the increased proteolytic resistance of factor XIII-stabilized clots. Preclinical studies indicate that the inclusion of factor XIII in fibrin sealants used for vascular grafting significantly reduces suture-hole blood loss. This has important implications for the successful control of bleeding in comparable clinical situations. The advantages of factor XIII stabilized clots (increased strength, resistance to proteolysis, promotion of wound healing) suggest that the presence of factor XIII in fibrin sealants may optimize their performance in the clinical setting. The aim of this paper is to review preclinical data that provide evidence for a potentially positive role for factor XIII in fibrin sealants.

Animals↗
PubMed2000

Prevention of suture hole bleeding using fibrin sealant: benefits of factor XIII.

BACKGROUND: Suture hole bleeding is a frequent complication in vascular surgery. The use of fibrin sealants (FSs) during surgery is reported to reduce blood loss by enhancing hemostasis. OBJECTIVES: Using a pig vascular graft model we investigated: (1) the use of FSs in vascular surgery and measured blood loss with and without the use of FSs; (2) the effect of factor XIII in FSs on hemostasis and blood loss; and (3) the effect of increasing FS incubation time on hemostasis and blood loss. MATERIALS AND METHODS: During surgery, a 3-cm incision was made in the carotid artery wall. Incisions were covered with a Gore-Tex (PTFE) patch sutured with Ethicon monofil 5/0 or 3/0. The resulting suture holes were treated according to study protocol. Study 1: Nine pigs received either FS treatment (n = 5) or no treatment (n = 4). Study 2: Twenty pigs underwent bilateral surgery; right (n = 20) and left (n = 20) patches received either FS with factor XIII (FS + FXIII) or FS depleted of factor XIII (FS - FXIII). Study 3: Bilateral surgery was carried out on 24 pigs; PFTE patches secured with Ethicon 3/0 were treated with FS and allowed to polymerize for 120 s (n = 12), 180 s (n = 12), or 240 s (n = 12) or with solid support/thrombin (n = 12). RESULTS: Study 1: Mean blood loss was significantly lower in the FS-treated group compared with untreated controls (9.2 +/- 10.6 mL vs 178.8 +/- 125.5 mL, mean +/- SD, P = 0.016). Study 2: Significantly less blood was lost in the FS + FXIII group than in the FS - FXIII group (Delta = 9.6 mL, P = 0. 02). Study 3: Blood loss was significantly higher from patches treated with solid support/thrombin compared with those treated with FS (P < 0.01). CONCLUSIONS: FSs containing factor XIII, such as Beriplast P, are effective in reducing suture hole bleeding and improving hemostasis during vascular graft procedures. The presence of factor XIII contributes to the efficacy of FSs and reduces the time to hemostasis. During vascular surgery, blood loss can be reduced significantly by the use of fibrin sealant compared with absorbable gelatin sponges coated with thrombin.

Animals↗
PubMed1996

The hypothetical N-glycan charge: a number that characterizes protein glycosylation.

The production of recombinant glycoprotein therapeutics requires characterization of glycosylation with respect to the lot-to-lot consistency. Here we introduce the ¿hypothetical N-glycan charge Z' as a parameter that allows to characterize the protein glycosylation in a simple, however, efficient manner. The hypothetical N-glycan charge of a given glycoprotein is deduced from the N-glycan mapping profile obtained via HPAE-PAD. In HPAEC, N-glycans are clearly separated according to their charge, i.e., their number of sialic acid residues, providing distinct regions for neutral structures as well as for the mono- di-, tri, and tetrasialylated N-glycans (Hermentin et al., 1992a). Z is defined as the sum of the products of the respective areas (A) in the asialo, monosialo, disialo, trisialo, tetrasialo, and pentasialo region, each multiplied by the corresponding charge: [formula: see text] Thus, a glycoprotein with mostly C4-4* structures will provide Z approximately equal to 400 (e.g., rhu EPO (CHO), Z = 361), a glycoprotein carrying largely C3-3* structures will amount to Z approximately equal to 300 (e.g., bovine fetuin, Z = 290), a glycoprotein with mostly C2-2* structures will have Z approximately equal to 200 (e.g., human serum transferrin, Z = 207, or human plasma AT III, Z = 180), and a glycoprotein carrying only high-mannose type or trunkated structures will provide Z approximately equal to 0 (e.g., bovine pancreas ribonuclease B, Z = 15, and hen ovomucoid, Z = 15, respectively). The determination of Z was validated in multiple repetitive experiments and proved to be highly accurate and reliable. Z may therefore be regarded as a new and characteristic parameter for protein N-glycosylation.

Amidohydrolases↗
PubMed1987

[Coronarography findings following systemic short-term lysis of acute myocardial infarct].

In 50 patients with acute infarction who were admitted within 6 hours after the beginning of the complaints randomizedly an intravenous streptokinase short-term lysis or a conventional heparin phenprocoumon treatment was performed and 4 weeks later the results were objectified by coronarography and ventriculography. The patients were subdivided into 3 groups: 1. control group (without fibrinolysis), 2. early lysis (within 4 hours) and 3. late lysis (4-6 hours). Four weeks after the infarction the proportions of the open infarction vessels are approximately of the same size in all three groups, the functional results are best (end-diastolic pressure and kinetics of the cardiac wall) in the group of patients who underwent an early lysis. Successfully lysed patients with remaining residual stenosis must be regarded as particularly threatened by infarction and remain under special control (residual angina, ergometrically objectified exercise tolerance, perhaps coronarography) in the phase of rehabilitation.

Aspirin↗
PubMed1986

[Clinical experiences with systemic high-dosage short-term fibrinolysis in acute myocardial infarct].

In 50 patients with acute myocardial infarction the systemic highly dosed short-term lysis with streptokinase took place within the 6-hour limit. 27 patients showed a normalisation of the ST-distance still during the treatment, 16 of whom did not develop any signs of necrosis in the ECG also in the further course. Pre-existing disturbances of rhythm receded under the infusion of streptokinase in 8 of 9 patients. In 11 patients arrhythmias appeared under the lysis, which could be brought under control in intensive-medical conditions. 4 patients died, 1 patient suffered a re-infarction. The results of the treatment were better, when the fibrinolysis began within 3 hours after the acute onset. Severe side effects did not appear.

Adult↗
PubMed1980

Studies of blood pressure in Tecumseh, Michigan. I. Blood pressure in young people and its relationship to personal and familial characteristics and complications of pregnancy in mothers.

Relationships between blood pressures (BPs) of young people and a number of personal, parental and familial characteristics have been assessed in the population of Tecumseh, Michigan. Systolic and fifth phase diastolic BPs were measured in 4500 persons under 20 years of age at the time of their first examination. Body size, fatness and heart rates of the subjects themselves were significantly related to their age- and sex-adjusted BP scores. The parents' BP scores were also correlated with those of the young subjects, and scores were significantly higher in those whose mothers had had high BP or toxemia in pregnancy of a stillbirth. A weak association between BP and socioeconomic circumstances was suggested by the slightly higher mean BP scores found in sons and daughters of men in blue collar jobs and of men and women with the least education. BP levels were not associated with birth order, sibship size or birth weight nor with the numbers of pregnancies, live births or abortions experienced by the mothers of young subjects. In a stepwise multiple regression, the most important determinants of BP were weight/height ratios of the subjects themselves and BP levels of their parents; a small additional effect of complications of pregnancy in the mother was detectable in the offspring 0--19 years laters.

Adolescent↗
PubMed1979

Isotope ratios in photosynthetic oxygen.

Axenic suspensions of the fresh water green alga Ankistrodesmus braunii were illuminated under aerobic conditions. The released gas mixture was introduced into the ion source of an isotope mass spectrometer, which recorded the 18O/16O ratio. The 18O content of the photosynthetic oxygen (approximately 0.199%) exceeded that of the cell water (approximately 0.197%) significantly.

Aerobiosis↗
PubMed1977

Habitual physical activity and glucose tolerance. Males age 16-64 in a total community.

The data being reported are part of an epidemiologic study of health and disease in an entire community, Tecumseh, Michigan. Approximately 1,300 males age 16-65 were classified into three groups on the basis of their habitual leisure and occupational physical activity. A blood sample was drawn one hour after a glucose challenge and analyzed for glucose concentration. A measure of body fatness (sun of four skinfolds) was also available on the men. Glucose concentration of the three physical activity groups was compared by analyses of variance within narrow age group. There was no significant relationship between glucose tolerance and habitual physical activity. There was a slight, but in some age groups significant, relationship between glucose tolerance and body fatness. The population was then divided within each age group into subgroups (thirds) by sum of skinfolds. The analysis was repeated in each age-fatness group. Glucose tolerance was better in the active men but only among the leanest subgroup of subjects.

Adipose Tissue↗