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D Boda

Publications and source records attributed to D Boda.

At least 19 recordsLinked to original sources
PubMed2000

Density Functional Theory and the Capillary Evaporation of a Liquid in a Slit.

Density functional theory is applied to a Lennard-Jones fluid near a single hard wall and in a slit formed by two walls. We use some simplified versions of the Weeks-Chandler-Andersen (WCA) and the Barker-Henderson (BH) theories. Only the most crude mean field version of the WCA theory, in which the hard-sphere correlation function is set equal to unity for all distances, seems useful. Use of the full WCA approximation is impractical because the effective hard-sphere diameter is density dependent. Generally, the best results are obtained using the BH macroscopic compressibility approximation. Our earlier study of "evaporation" of Lennard-Jones molecules in a slit is extended to other densities using the mean field theory. Copyright 2000 Academic Press.

Journal Article↗
PubMed1999

The caffeine metabolic ratio as an index of xanthine oxidase activity in clinically active and silent celiac patients.

BACKGROUND: The xanthine oxidoreductase system has been identified as one of the main sources of free radicals responsible for various forms of tissue injury. Because the intestinal villi are an important location of this enzyme, it was of interest to study the role of xanthine oxidase in gluten-sensitive celiac enteropathy, associated with characteristic villous atrophy. Measured by a noninvasive method, the ratio of caffeine metabolites excreted in the urine after a caffeine challenge had previously been shown to be indicative of the total xanthine oxidase activity of the patient. METHODS: The study involved 22 children with gluten-challenged celiac disease, exhibiting subtotal villous atrophy in specimens from the third intestinal biopsy in accordance with ESPGHAN criteria. Ten of the patients displayed overt clinical symptoms (active form), whereas 12 had no symptoms (silent form). Urinary caffeine metabolites were determined by high-pressure liquid chromatography. The total in vivo xanthine oxidase activity was expressed as the caffeine metabolite index. RESULTS: In patients with active celiac disease the xanthine oxidase activity index was considerably higher, whereas in those with silent disease it was significantly lower than the control value. A significant negative correlation was shown between the index indicative of xanthine oxidase activity and the serum iron level of the patients. CONCLUSIONS: Activation of xanthine oxidase may play a role in the pathogenesis of active celiac disease with definite malabsorption, gastrointestinal symptoms, and anemia. The caffeine test reflects the difference in the pathogenetic mechanism leading to the mucosal lesion and clinical symptoms of active and silent forms of celiac disease.

Caffeine↗
PubMed1998

[Possible pitfalls in giving expert opinion in legal actions against medical services].

The authors report their experience in cases under legal action against medical service needing expert opinion. By the rapid development and differentiation of medical science in the recent years the possibility of making mistake in every day practice increased, on the other hand this circumstance includes also occurrence of the pitfalls in giving expert opinion in legal actions against medical service.

Expert Testimony↗
PubMed1998

Surface tension, glutathione content and redox ratio of the tracheal aspirate fluid of premature infants with IRDS.

OBJECTIVE: Determination of the surface tension (ST), the total glutathione (GL) content and the ratio of oxidized glutathione (GSSG) to reduced glutathione (GSH) in the tracheal aspirate (TA) of newborn infants with IRDS. METHODS: The ST of the TA was determined by monitoring the fluid level pulsated in a capillary glass tube by means of a digitalized videocomputerized picture analysis program, a technique developed in our laboratory. The concentrations of GSSG and total GL in the TA were determined enzymatically with glutathione reductase. All results of laboratory tests were referred to the total phospholipid (PL) concentration. Patients, Experimental Material: TA samples were collected from 32 intubated premature and newborn infants admitted to the NICU with IRDS during the first 2 weeks of their lives. Control samples were obtained from 11 children prior to elective surgery. RESULTS: The ST relative to the PL content (surface tension index, STI) was significantly lower in the newborns with IRDS than in the control group, and the concentration of GSH in the TA was also markedly decreased in all IRDS infants studied. The concentration of GSSG and the ratio of GSSG to GSH were significantly higher in the severe cases and in those with an unfavourable prognosis. Surfactant treatment had a protective effect against oxidative stress, it induced a decrease in both the GSSG concentration and in the GL redox ratio (GSSG/GSH) in the TA. There was a close correlation between the GSH content and the STI value of the samples studied. CONCLUSION: Oxidation and consequent depletion of GSH in the TA may be an aggravating factor in the development of the insufficient surface activity in intubated newborns with IRDS.

Body Fluids↗
PubMed1997

Oxidative stress induced by bloodless limb surgery on humans.

Measure of oxidative stress were studied in blood samples from 10 patients undergoing bloodless lower limb surgery. Ischaemia induced a significant increase in plasma hypoxanthine concentration and xanthine oxidase activity both in the operated leg and in the systemic circulation. Five minutes after reperfusion, ratio of xanthine oxidase/total xanthine oxidase and dehydrogenase activities rose moderately, whereas at 20 min xanthine oxidase accounted for all xanthine oxidoreductase activity in the systemic circulation. A significant increase in blood glutathione redox ratio, enhanced oxidation of haemoglobin to methaemoglobin and rise in plasma haemoglobin concentration were present only in the operated limb. Thus, although the level of the potential free radical generators rose significantly both locally and in the systemic circulation, oxidative stress, as indicated by blood glutathione and erythrocyte injuries, remained limited to the reperfused leg.

Aged↗
PubMed1997

Measurement of surface tension in biological fluids by a pulsating capillary technique.

Ever since the discovery of the antiatelectatic function of the pulmonary surfactant, the measurement of surface tension (ST) has been of increasing importance in respiration physiology and clinical research. For the determination of ST, the elevation of the level of a fluid artificially pulsated in a capillary glass tube was monitored, and ST was calculated with the digitalized video-computerized picture analysis program Surftens. The biological relevance of the method is given by the Gibbs-Thomson principle, according to which surface-active lipids stream towards the surface by an adsorptive process; on pulsation of the fluid in a capillary glass tube, therefore, ST is gradually decreased to a minimal value. ST values of 60 amniotic fluid samples collected from pregnancies with different gestation times were determined. A multiple regression analysis of the results, including other parameters (total protein content, total lipid content, phospholipid content and microviscosity), indicated that this method may enhance the precision of the determination of gestation time. Precision analysis of various samples proved that this technique gives well-reproducible results under the given standardized conditions. The main field of application of the method may be in clinical practice and in studies on as yet inadequately known factors affecting the ST of biological fluids.

Adsorption↗
PubMed1996

[Rh alloimmunization].

Explore the source record for details and available documents.

Blood Transfusion, Intrauterine↗
PubMed1995

[Misunderstandings and pitfalls on the narrow pathway of medical ethics].

Due to the scientific progress and the rapid changes in social circumstances, medical ethics became a complicated and difficult science. On the basis of fundamental and simple principles of medical ethics (salus aegroti suprema lex) the author tries to take standpoint in questions arisen in his practice in which the medical aspect was not necessarily obvious. It can be ethically faulty when more then necessary is provided to the patients (in prescribing medicine, in welfare, in performing examinations). It is necessary that the steadily increasing medical specialization goes together with the better cooperation between the medical disciplines and with wider distribution of special experience. The system of the medical honorarium should be entirely open and publicly regulated. It is a medical ethical obligation to place the organs of brain death cases suitable for transplantation at the disposal of patients requiring it. In the field of reproduction not the suspicion alone but the undoubtebly proven injury of fetus only can be a sufficient medical indication for the termination of pregnancy. The medical person by his attitude in creating optimal conditions for the perinatal care has to do his best in avoiding any heartlessness, contralily, in promoting willingness in the parents to have children.

Ethics, Medical↗
PubMed1994

Blood glutathione redox ratio as a parameter of oxidative stress in premature infants with IRDS.

Oxygen toxicity is thought to play an important pathogenic role in several neonatal diseases, including idiopathic respiratory distress syndrome (IRDS). Therefore, the development of a reliable measure of the actual oxidative stress status of patients would be of great clinical significance. In order to obtain information about the oxidative stress during the first week of life in premature infants with IRDS, the blood concentrations of oxidized and reduced glutathione, as well as their molar ratios, were determined by a highly sensitive, specific enzymic assay. The fractional inspired oxygen concentrations needed to maintain adequate arterial oxygen tension and the arterio-alveolar oxygen ratios were chosen as parameters indicating the severity of illness in premature infants at a given time. There was a highly significant positive correlation between the glutathione redox ratios and the fractional inspired oxygen concentrations. A maturity-related difference was also found; the oxidized glutathione concentrations were the highest in the least mature infants, accompanied by a pronounced compensatory rise in the reduced glutathione concentrations as well. A significant negative correlation was found between the arterio-alveolar oxygen ratio and the glutathione redox ratio: i.e., an improvement in oxygenation was accompanied by a decrease in the glutathione redox ratio. The efficient recycling of reduced glutathione in erythrocytes providing antioxidant protection for premature infants, permits the use of the blood glutathione redox ratio as a noninvasive measure of in vivo oxidative stress.

Antioxidants↗