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Biomedical subjects

I Balogh

Publications and source records attributed to I Balogh.

At least 37 records · Page 2Linked to original sources
PubMed2000

The Leiden mutation of coagulation factor V in Hungarian SLE patients.

We studied the prevalence and the effect of coagulation factor V Leiden mutation on the occurrence of thrombotic episodes in 120 Hungarian patients having systemic lupus erythematosus (SLE) with or without antiphospholipid antibody. The frequency of the factor V Leiden mutation in Hungarian SLE patients was 13%, which is comparable with those found previously in a healthy Caucasian population. The incidence of venous thrombosis among factor V Leiden carriers has been found to be higher (odds ratio [OR] 1.7) than it is in patients without Leiden mutation (38% vs 29%). In addition, the frequency of venous thrombosis in the heterozygous SLE patients (OR 8.4 [confidence interval (CI) 0.8-83.9] P = 0.06) is dependent on the coexistence of other risk factors, such as antiphospholipid antibody. Moreover, among heterozygous factor V SLE patients, the Leiden mutation could explain the tendency to have significantly higher prevalence of fetal losses (OR 3.9 [CI 1.2-12.0] P = 0.02) and higher prevalence of cerebrovascular lesions, cardiac valvular abnormalities, and Raynaud's syndrome than that found in individuals without factor V Leiden mutation of those having antiphospholipid antibody. Systemic lupus erythematosus patients with combined defects suffer more severely from thrombosis than those with a single risk factor do, suggesting that thrombophilia is a multifactorial disorder in SLE, also. Although, the factor V Leiden mutation does not seem to be a significant risk factor for venous thrombosis in SLE, these data demonstrate that Leiden mutation can be regarded as an additive thrombogenic factor providing higher predisposition to several vasoocclusive disorders in SLE.

Abortion, Spontaneous↗
PubMed2000

Effect of Val34Leu polymorphism on the activation of the coagulation factor XIII-A.

Coagulation factor XIII (FXIII) is a protransglutaminase involved in the last step of the coagulation cascade by stabilising the fibrin clot. Recently, a common variation (FXIII Val34Leu) has been associated with a decreased risk of myocardial infarction and deep venous thrombosis. Val34Leu is critically located near the thrombin activation site of FXIII-A. In this study we investigated its effects on the activation of FXIII. Both recombinant and platelet-derived FXIII Val34Leu variants were shown to be more susceptible to thrombin cleavage than the wild type FXIII. The rate of enzymatic activation of FXIII Val34Leu was found increased, however, the specific activity of fully activated wild type FXIII and the Val34Leu mutant did not differ. During the course of thrombin-induced activation of FXIII fibrin gamma-chain dimerisation and alpha-chain polymerisation developed more rapidly with the Val34Leu mutant. The increased rate of fibrin stabilisation brought about by the Val34Leu FXIII seems to be paradoxically associated with a protective effect against pathological thrombosis.

Animals↗
PubMed2000

A modified, optimized kinetic photometric assay for the determination of blood coagulation factor XIII activity in plasma.

BACKGROUND: Blood coagulation factor XIII (FXIII) is a zymogen that is transformed into an active transglutaminase by thrombin and Ca(2+). FXIII plays an essential role in fibrin stabilization and in the protection of fibrin from proteolytic degradation. No convenient method has been available for the measurement of FXIII activity in plasma. The aim of the present study was to improve and optimize a kinetic photometric FXIII assay originally developed in our laboratory. METHODS: In the assay, FXIII was activated by thrombin and Ca(2+). Fibrin polymerization was prevented by an inhibitory tetrapeptide. Glycine-ethyl ester and a glutamine residue of a synthetic dodecapeptide served as acyl acceptor and acyl donor transglutaminase substrates, respectively. The amount of ammonia released during the reaction was monitored using glutamate dehydrogenase and NADPH. RESULTS: The use of a new glutamine substrate and optimization of activator and substrate concentrations increased sensitivity. Substitution of NADPH for NADH and introduction of an appropriate blank eliminated systemic overestimation of FXIII activity. The recovery of FXIII was 96%, the assay was linear up to 470 U/L, the detection limit was 1 U/L, and the imprecision (CV) was <8% even at very low FXIII activities. A reference interval of 108-224 U/L (69-143%) was established. The results correlated well with results obtained by an immunoassay specific for plasma FXIII. CONCLUSIONS: The optimized FXIII assay is a simple, rapid method for the diagnosis of inherited or acquired FXIII deficiencies and increased FXIII concentrations. It can be easily adapted to clinical chemistry analyzers.

Adult↗
PubMed2000

The role of platelet-activating factor (PAF) antagonists and nitric oxide in cardiac actions of PAF. Electrophysiological and morphological study.

Electrophysiological and ultrastructural effects of platelet-activating factor (PAF) antgonists, WEB 2086 and BN 52021 were compared in isolated guinea-pig hearts preparations. We studied the possible role of nitric oxide (NO) in electromechanical actions of PAF. Isometric twitches and intracellular action potentials (APs) were recorded from guinea-pig right ventricular papillary muscles and left atria. For electron microscopic study the hearts were perfused according to Langendorff technique. WEB 2086 (5 x 10(-9)-5 x 10(-7) M) significantly shortened the duration of atrial AP without changing the ventricular one, however, BN 52021 decreased both of them. The shortening of atrial and ventricular AP duration (APD) by both PAF antagonits were abolished by 4-aminopyridine (10(-3) M), a blocker of one type of K+ channels (IKto). Glibenclamide (10(-6) M) the blocker of ATP-dependent K channels prevented the shortening effect of BN 52021 (10(-6) M) on ventricular APD. Electron microscopic study of myocardial samples from hearts subjected to 30 min hypoxia/reoxygenation showed intracellular oedema, intramitochondrial swelling and fragmentation of mitochondrial christae, separation of intercalated disc. Pretreatment with WEB 2086 (5 x 10(-7) M) warded off nearly all damage caused by hypoxia/reoxygenation. Both WEB 2086 and NO synthase inhibitor NG-nitro-L-arginine methyl esther (L-NAME) (10(-3) M) abolished the negative inotropic effect of PAF (10(-7), 10(-6) M). L-NAME prevented the shortening of APD induced by 10(-7) M PAF. These results suggest that PAF may be responsible for myocardial ischemia and the beneficial effects of PAF antagonists in this pathological process could be due to their possible K+ channel stimulator property. These data support the possibility that NO contributes to the cardiac electromechanical alterations induced by PAF.

4-Aminopyridine↗
PubMed2000

Membranous glomerulonephritis in a patient with inherited activated protein C resistance.

We present a patient with membranous glomerulonephritis, several clinical complications of the antiphospholipid syndrome and ulcerative colitis, but without lupus anticoagulant and antiphospholipid/cofactor antibodies. Immunological studies--other antibodies--were negative and failed to show enough criteria for any autoimmune diseases. Evaluation of her laboratory tests for hereditary thrombophilia revealed a heterozygous form of the Leiden mutation that might be associated with widespread vasculopathy. An interesting possibility is that the inherited activated protein C resistance could be an additional risk factor for vaso-occlusive manifestations appearing as a clinical sign of cardiovascular diseases and nephropathy.

Activated Protein C Resistance↗
PubMed1999

Fish processing work: the impact of two sex dependent exposure profiles on musculoskeletal health.

OBJECTIVES: To evaluate the impact of work tasks, physical exposure, and psychosocial factors on the risk of musculoskeletal disorders in men and women, in a defined industrial setting. METHODS: 116 male and 206 female fish industry workers were compared with 129 men and 208 women with more varied work. Physical and psychosocial work load as well as musculoskeletal complaints were recorded by a questionnaire. A physical examination was performed and an observation method was used for work evaluation. 196 male and 322 female former fish processing workers received a postal questionnaire. RESULTS: The women workers in the fish industry had worse working conditions than the men for repetitiveness, constrained neck postures, and psychosocial work environment. They also had higher prevalences of complaints of the neck and shoulder (prevalence odds ratio (POR) 1.9; 95% confidence interval (95% CI) 1.1 to 3.2), neck and shoulder and elbow and hand complaints (POR 2.9; 95% CI 1.8 to 4.7 and POR 2.8; 95% CI 1.6 to 4.7, respectively). The women more often than the men left the industry because of neck and upper limb complaints. Also, women in other work had a higher prevalence of complaints of the neck and shoulder (POR 2.3; 95% CI 1.1 to 5.1) than the men. The men in the fish processing industry had a higher prevalence of complaints of the neck and shoulder than the men in other work (POR 3.6; 95% CI 1.6 to 8.0). This difference was not shown up by the questionnaire. CONCLUSIONS: Despite superficially similar work, there were clear sex differences in physical exposure and psychosocial work environment. Work in the fish processing industry was associated with a high risk of neck and upper limb disorders in women, which was probably mainly due to their extremely repetitive work tasks; the corresponding men had less repetitive work and less disorders. Also, a healthy worker effect on neck and upper limb disorders was found. The advantage of a physical examination compared with a questionnaire is clearly shown.

Adult↗
PubMed1999

Interindividual variation of physical load in a work task.

OBJECTIVES: This study analyzed the variation in physical work load among subjects performing an identical work task. METHODS: Electromyographs from the trapezius and infraspinatus muscles and wrist movements were recorded bilaterally from 49 women during a highly repetitive industrial work task. An interview and a physical examination were used to define 12 potential explanatory factors, namely, age, anthropometric measures, muscle strength, work stress, and musculoskeletal disorders. RESULTS: For the electromyographs, the means of the 10th percentiles were 2.2% and 2.8% of the maximal voluntary electrical activity (%MVE) for the trapezius and infraspinatus muscles, respectively. However, the interindividual variations were very large [coefficients of variation (CV) 0.75 and 0.62, respectively]. Most of the variance could not be explained; only height, strength, and coactivation of the 2 muscles contributed significantly (R2(adj)0.20-0.52). The variation was still large, though smaller (CV < or =0.63), for values normalized to relative voluntary electrical activity (RVE). For the wrist movements, the median velocity was 29 degrees per second, and the interindividual variations were small (CV < or =0.24). Six factors contributed to the explained variance (R2(adj)0.12-0.55). CONCLUSIONS: The interindividual variation is small for wrist movements when the same work tasks are performed. In contrast, the electromyographic variation is large, even though less after RVE normalization, which reduces the influence of strength, than when MVE is used. Because of these variations, several electromyographs are needed to characterize the exposure of a specific work task in terms of muscular load, and individual electromyographs are preferable when the worker' s risk of myalgia is being studied.

Adult↗
PubMed1998

[Prevention of thromboembolic side effects of oral contraceptives: methodologic recommendations].

The authors analyse the incidence of thromboembolic complications during combined oral contraception. Among genetic factors predisposing to venous thrombosis and thromboembolic disease, they present, with the help of three case histories, the molecular biology of activated protein-C resistance, the newly discovered and most frequently implicated pathogenetic factor of inherited thrombophilia. Among 350 asymptomatic women requesting prescription for an oral contraceptive they found a 9.1% frequency of heterozygote Leiden-mutation carriers. For the prevention of a rare, however, almost always life-threatening complication the authors recommend activated protein C-resistance analysis to be carried out whenever an oral contraceptive is prescribed for the first time. Positive results will provide life-time aid in avoiding factors which increase the risk of thromboembolic disease. Negative results may help reducing the number of those who, risking an unwanted pregnancy, are hesitant to start on oral contraceptives for their implication in thromboembolic disease.

Adolescent↗
PubMed1998

Changes in cardiac electrophysiology, morphology, tissue biochemistry and vascular reactions in glutathione depleted animals.

The effects of acute and chronic glutathione depletion (single i.p. injection of 3 mmol/kg L-buthionine-S,R-sulphoximine and 2 mmol/kg for 4 days) on heart action potential (AP) characteristics, electronmicroscopy, cytochemistry and biochemistry and vascular contractility and nitric oxide-mediated relaxation were studied in rats and guinea pigs. In guinea pig cardiac preparations both acute and chronic glutathione depletion caused a significant decrease of maximum rate of rise of depolarization phase and duration of action potential AP(APD) at 25, 50, and 90% of repolarization but did not modify the other AP parameters. The contractile responses of helically cut aortic strips to norepinephrine were not altered by chronic glutathione depletion but the relaxing responses of precontracted preparations to acetylcholine were significantly reduced both in rats and guinea pigs. Morphologically there were indications of permeability changes, intracellular and interstitial edema and myofilament damage in the myocardium. There was also a decrease in cytochromoxydase and succinyl dehydrogenase activities both in rats and guinea pigs. The present data suggest that glutathione depletion may influence the Na+ and K+ channel activities, causes morphological and biochemical changes in cardiac preparations and may interfere with nitric oxide generation or its action in aortic strips.

Action Potentials↗
PubMed1997

Quantifying work load in neck, shoulders and wrists in female dentists.

OBJECTIVE: To assess the work load in neck and upper limbs of dentists. METHODS: Twelve right-handed female dentists (six with and six without a history of definite neck/shoulder disorders, pair-wise matched for age) were studied when performing authentic dental work. Electromyography (EMG) was used to quantify the muscular load of the shoulders bilaterally and of the right forearm. Positions and movements of the head and wrists were measured, using inclinometers and electrogoniometers. RESULTS: During work, the median load for the right upper trapezium muscle was 8.4% of the maximal voluntary EMG activity (MVE); during 90% of the time the load was > or = 3.3% MVE ("static" load). The figures were somewhat lower on the left side (7.0% and 2.5% MVE, respectively). Subjects with disorders had over all lower load levels for the trapezius muscles, although not statistically significant at < 0.05, than those without disorders. During a standardized reference contraction for the trapezius, the load was 17% MVE, and the quotient between MVE and torque [normalized to maximal voluntary torque (MVC)] was 0.5. These figures may be used for transformations. The muscular load on the right forearm was similar to the loads on the trapezius. The head was, on average, forward tilted > or = to 39 degrees, and during 10% of the time > or = 49 degrees. The left hand was held in more static positions, with palmar flexion and ulnar deviation, also reflected by lower angular velocities and repetitiveness, as compared with the right one, which was dorsiflexed. CONCLUSIONS: Dentists are exposed to high load on the trapezius muscles bilaterally, and steep, prolonged forward bending of the head. Further, for the wrists the postures were constrained, but the dynamic demands were low.

Adult↗
PubMed1996

Knee moment at work: validation of a questionnaire based on knee moment in working life.

Classifications of occupations, such as those of the International Labor Organization, have previously been constructed with respect to the physical strain and joint moment to be expected in conjunction in a profession. To detect which occupational activities specifically induce high knee moments, we designed a questionnaire to analyze walking, knee bending, climbing of stairs and ladders, and jumping during three consecutive 15-year exposure periods in the professional lives of 920 consecutive residents [329 men with a mean age of 72 (range 47-96) and 561 women with a mean age of 77 (range 47-96)] drawn from the population records of the City of Malmö. The answers, classified into three categories with respect to knee joint moment, were compared with a classification of the occupations of all probands according to the same principles by three independent specialists in industrial hygiene. The two classifications showed a high degree of agreement, with Cramer's V ranging from 0.49 to 0.6, suggesting a co-variance with a common variable, i.e. the true work-related knee moment.

Age Distribution↗