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Biomedical subjects

B Tiran

Publications and source records attributed to B Tiran.

At least 19 recordsLinked to original sources
PubMed1999

Humoral immune response to human cytomegalovirus in patients undergoing percutaneous transluminal coronary angioplasty.

Possible causal relations between prior human cytomegalovirus (HCMV) infection and atherosclerosis and between HCMV reactivation and restenosis after coronary angioplasty have been suggested. We investigated patterns of antibodies directed to HCMV in 112 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) and in a group of sex- and age-matched controls (blood donors without evidence of atherosclerosis). Levels of antibodies to HCMV were measured by enzyme-linked immunosorbent assay (ELISA) of serum samples drawn before and 5 weeks after PTCA. To further differentiate the humoral immune response, we specifically tested antibody reactivity towards four single HCMV proteins (IE2, p52, pp150, and pp65) by recombinant ELISAs. We found that 73% of PTCA patients and 69% of sex- and age-matched controls were seropositive for HCMV (odds ratio, 1.2 [not significant]). The corresponding odds ratios for matched pairs ranged in the recombinant ELISAs from 1.2 to 1.4. Patients had more often high titers of anti-HCMV antibodies (11 versus 4%; odds ratio = 3.3 [0.9 to 15.2]; P = 0.052) and high titers of anti-pp150 antibodies (13 versus 4%; odds ratio = 6.0 [1.3 to 38.8]; P = 0.008). Anti-HCMV immunoglobulin M antibodies were not detected in any patient. There was no evidence of acute HCMV reactivation after PTCA, since the titers of antibodies to the investigated recombinant proteins did not increase at 5 weeks after PTCA. Our results show a limited association between prior HCMV infection and coronary artery disease. We infer that positive anti-HCMV titers are not a major risk factor at the time of disease manifestation. However, this study cannot rule out a possible role of HCMV at earlier stages of the atherosclerotic process. Recombinant ELISAs provide a valuable tool for investigating the antiviral immune response.

Adult↗
PubMed1999

Coronary angioplasty induces rise in Chlamydia pneumoniae-specific antibodies.

Chlamydia pneumoniae is frequently found in atherosclerotic lesions, and high titers of specific antibodies are associated with increased risk for acute myocardial infarction. However, a causative relation has not been established yet. We performed a prospective study of 93 patients undergoing percutaneous transluminal coronary angioplasty (PTCA) to investigate whether angioplasty influences Chlamydia-specific antibody titers and whether there is an association with restenosis. Blood samples were obtained before and 1 and 6 months after angioplasty. Antibodies against chlamydial lipopolysaccharide and against purified C. pneumoniae elementary bodies were measured by enzyme-linked immunosorbent assay (ELISA). After angioplasty, the prevalence of antibodies to lipopolysaccharide rose from 20 to 26% for immunoglobulin A (IgA), from 53 to 64% for IgG, and from 2 to 7% for IgM (P = 0.021, 0.004, and 0.046, respectively). There was a rapid increase of mean antibody titers of all antibody classes within 1 month of PTCA. During the following 5 months, antibody titers decreased slightly but were still higher than baseline values. Results of the C. pneumoniae-specific ELISA were essentially the same. The rise of anti-Chlamydia antibodies was not caused by unspecific reactivation of the immune system, as levels of antibodies against cytomegalovirus did not change. Neither seropositivity nor antibody titers were related to restenosis. However, increases in mean IgA and IgM titers were restricted to patients who had suffered from myocardial infarction earlier in their lives. In conclusion, we show that PTCA induces a stimulation of the humoral immune response against C. pneumoniae. These data support the idea that plaque disruption during angioplasty might make hidden chlamydial antigens accessible to the immune system.

Adult↗
PubMed1998

Effects of pancreatic enzyme preparations on erythrocyte glutathione peroxidase activities and plasma selenium concentrations in cystic fibrosis.

To substitute for exocrine pancreatic insufficiency, patients with cystic fibrosis (CF) take pancreatic enzymes (PE) originating from porcine pancreas. Five different pancreatic enzyme preparations used by our patients contained 0.5-1.4 microg selenium per g tablet. In patients taking PE in doses that were gradually increased to improve fat absorption during a 48-month period, the effects of PE dose on erythrocyte selenium-dependent glutathione peroxidase (SeGSH-Px) activities and plasma selenium concentrations were studied. At baseline, erythrocyte SeGSH-Px activities were significantly lower in patients (p=.01), while plasma selenium concentrations did not differ between patients and healthy subjects. When PE dose and, consequently, selenium intake from PE was increased, erythrocyte SeGSH-Px activities (p < .001) and plasma selenium concentrations (p=.02) increased. Changes in SeGSH-Px activities during the initial 8 months correlated with those in selenium intake from PE (r=0.67, p < .001). Plasma selenium concentrations plateaued at 12 months and erythrocyte SeGSH-Px activities did so at 36 months, when patients had reached SeGSH-Px activities similar to those of healthy subjects. At 48 months, patients took an average lipase dose of 17400 U x kg(-1) x d(-1) and selenium dose from PE of 0.53 microg x kg(-1) x d(-1). We conclude that selenium content of PE preparations has a significant effect on SeGSH-Px activity in patients with CF. This form of selenium supply needs to be taken into account when selenium supplements are given to patients with CF.

Administration, Oral↗
PubMed1998

Prior cytomegalovirus infection does not predict clinical outcome after percutaneous transluminal coronary angioplasty.

BACKGROUND: A direct association between human cytomegalovirus (HCMV) infection and the development of restenosis after coronary angioplasty has been suggested. The aim of this prospective study was to evaluate the value of HCMV serology in predicting the clinical outcome after percutaneous transluminal coronary angioplasty (PTCA). METHODS AND RESULTS: 112 patients undergoing elective PTCA were included in the study. HCMV antibody levels were measured by ELISA. Cardiac events within a follow-up period of 6 months after PTCA were defined as (1) progression or recurrence of anginal complaints and/or a positive exercise test; (2) restenosis that required repeat revascularization. 73% of PTCA patients were seropositive for HCMV. Successful PTCA was achieved in a total of 94 patients, who were followed for 6 months. In 31/94 patients (33%) cardiac events occurred and in 15/94 (16%), this could be related to restenosis. We found no statistically significant difference between seropositive and negative patients with respect to anginal complaints or the need for revascularization. There was no evidence of acute reactivation, since titers of anti-HCMV antibodies did not increase after PTCA. CONCLUSION: This study shows that the clinical outcome after PTCA is not related to the HCMV serostatus of the patient. Therefore, our data do not support the hypothesis that serological markers of HCMV infection are of clinical importance for the assessment of a patient's individual risk after PTCA. This does not preclude a role for local reactivation of HCMV at the site of angioplasty.

Acute Disease↗
PubMed1997

Antioxidant status in patients on chronic hemodialysis therapy: impact of parenteral selenium supplementation.

Reactive oxygen species may be involved in a broad pattern of tissue injury in patients on regular hemodialysis therapy and, in fact, increasing evidence suggests that the antioxidative system is compromized in these patients. One factor contributing to this reduction of antioxidative capacity is selenium deficiency. The present investigation was undertaken to further define the extent and type of impairment of the oxygen radical scavenger system in chronic hemodialysis patients and to evaluate the impact of selenium supplementation. Twelve non-wasted patients (6 male, 6 female, mean age of 58 years) on chronic hemodialysis for a minimum of 5 months (mean 46 months) were supplemented intravenously with 400 mg selenium (as sodium selenite) thrice weekly after each hemodialysis session over 8 weeks. Blood samples were taken before the start, at intervals of 2 weeks during, and 4 weeks after termination of supplementation. Concentrations were evaluated of selenium and alpha-tocopherol in plasma and erythrocytes, of retinol and ascorbic acid in plasma, of glutathione and the activities of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and, catalase (CAT) in erythrocytes. Lipid peroxidation endproducts were measured as malondialdehyde (MDA) in plasma. In patients on hemodialysis multiple alterations of the antioxidative system were present and the concentrations of selenium in plasma, of glutathione and the activity of GSH-Px in erythrocytes were profoundly decreased (p < 0.001). Selenium supplementation improved the selenium status of the patients, as indicated by an increase in selenium concentrations in plasma and erythrocytes and erythrocyte GSH-Px activity. Improvement in antioxidative capacity was further documented by an increase in alpha-tocopherol in erythrocytes. Plasma MDA showed a transient decrease after 6 weeks and increased activities of SOD and CAT were dampened. No effect was seen on plasma concentrations of ascorbic acid, a-tocopherol and retinol. We conclude that patients on chronic hemodialysis therapy manifest a profound depression in antioxidative potential and a selenium deficiency. Selenium supplementation improves the oxygen radical scavenger system and increases selenium concentrations in plasma and erythrocytes and the activity of selenium dependent glutathione peroxidase. Thus, selenium should also be considered for micronutrient supplementation in patients on chronic hemodialysis therapy.

Adult↗
PubMed1995

Effects of the bradykinin antagonist, icatibant (Hoe 140), on pancreas and liver functions during and after caerulein-induced pancreatitis in rats.

It has been found earlier that the bradykinin antagonist, icatibant (Hoe 140), prevents the pancreatic oedema and the ensuing hypotension and haemoconcentration, and facilitates the removal of activated enzymes form the tissue during caerulein-induced acute pancreatitis. For a potential therapeutic use of the compound in clinical situations it is essential to investigate whether the associated increase in enzyme activities in the blood serum has any adverse effects on the pancreas itself or on other organs. Normal amylase secretion into the biliopancreatic duct stimulated by a low dose of caerulein (0.4 nmol kg-1 h-1, i.v.) was not affect by icatibant (100 nmol kg-1, s.c.) Acute pancreatitis, induced by a high dose of caerulein (4 nmol kg-1 h-1 for 2 h, i.v.), resulted in elevations in the activities of amylase and lipase in the pancreatic tissue and in the blood serum lasting for at least 4 h after the end of the caerulein infusion. While the rise in enzyme activities in the blood serum was augmented in icatibant-treated rats only at the end of the caerulein-infusion, the enzyme accumulation in the pancreas was significantly reduced by icatibant for at least 4 h after the end of the caerulein infusion. The secretion of amylase and lipase into the biliopancreatic duct was significantly increased only during the first 20 min of acute pancreatitis; in rats pre-treated with icatibant, no significant increase could be observed. Twenty-four hours after induction of pancreatitis, a low-dose caerulein stimulation of the exocrine function of the pancreas led to a reduced but sustained secretion of amylase regardless of whether the animals had received icatibant or not. During the first 45 min of pancreatitis, blood glucose concentrations were significantly reduced, but returned to values not different from those obtained in saline-infused controls. This effect was not affected by icatibant. No changes in the response to an i.v. glucose tolerance test were found on the day after induction of acute pancreatitis. The serum activities of glutamic pyruvic transaminase and gamma-glutamyl transpeptidase determined up to 24 h after induction of pancreatitis were not different from saline controls. icatibant had no effect on the activities of these enzymes. It is concluded that during caerulein-induced acute pancreatitis normal exocrine secretion of pancreatic enzymes into the pancreatic duct ceases almost immediately. Pre-treatment with icatibant significantly reduces the accumulation of activated enzymes in the pancreatic tissue for several hours after induction of pancreatitis while a concomitant augmentation in enzyme activities in the blood serum lasts much shorter. There is no indication of adverse effects on the function of the endocrine or exocrine pancreas and that of the liver, either during the acute stages of pancreatitis or during the recovery period.

Acute Disease↗
PubMed1994

[Photometric determination of HbA1c levels in clinical practice].

This study was undertaken to evaluate the routine use of a new immunological photometer to measure the concentration of HbA1c in whole blood from 155 patients. The basis of the measurement is a latex agglutination reaction in which a monoclonal antibody as epitope recognizes glucose bound to HbA1c. The result is available within 9 min. High-pressure liquid chromatography (HPLC) served as control method. The photometer proved to be very precise (all coefficients of variant < 2.5%), and the values obtained agreed well with those by HPLC (y = 0.952x-0.12; r = 0.986; P < 0.001). The reference ranges for the photometrically measured HbA1c values (4.4-5.9%), obtained for 40 patients, agreed well with those by HPLC (4.6-6.2%). Interference study discovered no effect on the measured value by anaemia, polycythaemia or high rheuma factor (n = 31). In 12 patients on dialysis the photometer recorded significantly lower values than HPLC (P < 0.0005). It is possible that in these cases the photometer values are more accurate because the method is not affected by carbamylated haemoglobin. False results were obtained by the photometer in two patients with leucocytosis (79,000 and 216,000/microliters, respectively) due to chronic lymphocytic leukaemia.

Adult↗
PubMed1994

Automated determination of glycated hemoglobin: comparative evaluation of five assay systems.

We evaluated four newly introduced assays for determination of glycated hemoglobin allowing the processing of large amounts of samples in a clinical routine laboratory. These methods were compared to the Bio-Rad Diamat system. The investigated methods were the Merck Hitachi L-9100, a fully automated HPLC analyser, the Abbott IMx glycated hemoglobin ion capture assay, the DAKO HbA1c enzyme linked immunosorbent assay (ELISA), and the Boehringer-Mannheim HbA1c Tinaquant turbidimetric assay. All methods showed generally acceptable precision and good accordance with the Diamat system. Interference study showed influence of anaemia, polycythemia, rheumatoid factor, and chronic hemodialysis on the values of the DAKO ELISA and of anaemia and polycythemia on the values of the Boehringer-Mannheim Tinaquant assay. All of the investigated methods allow referring of results either as measured or standardized HbA1c values, the latter obtained after calibration with reference to an ion exchange high-pressure liquid chromatography method. Our data confirm the feasibility of this kind of standardisation of glycated hemoglobin assays, allowing direct comparison of results from various determination methods.

Adult↗
PubMed1993

Immunoquantification of lipoprotein(a): comparison of nephelometry with electroimmunodiffusion.

A new fully automated nephelometric immunoassay for lipoprotein(a) quantification in human serum was evaluated using the Behring Nephelometer Analyzer. The assay exhibited a good linearity in the concentration range of 110-1,770 mg/l; at higher concentrations, samples were automatically diluted by a factor of 4. The method is simple, robust, and shows an excellent stability of the calibration curve over several weeks. Intra-assay and day-to-day coefficients of variation were 2% and 4.5%, respectively. The method correlated well with electroimmunodiffusion (r = 0.977; n = 123; P = 0.0001). Unspecific turbidity as expressed by an elevated blank value occurred in 3% of all freshly measured samples (n = 392). Storage of the samples for 1 week at 4 degrees C had no significant influence on the results. Frozen sera, on the other hand, cannot be assayed by this method. We believe that this assay is well suited for use in clinical routine work.

Calibration↗
PubMed1993

Pathological events in experimental acute pancreatitis prevented by the bradykinin antagonist, Hoe 140.

1. In a previous investigation, Hoe 140, a specific and potent bradykinin B2 receptor antagonist, prevented the pancreatic oedema and the hypotension observed during acute experimental pancreatitis; however, it augmented the associated rises in the serum activities of pancreatic enzymes. Therefore, we have now investigated the consequences of the pancreatic oedema for the fate of activated enzymes released into the tissue during the course of acute pancreatitis. 2. Acute oedematous pancreatitis was induced in rats, pretreated with captopril (50 mumol kg-1, i.p.), by hyperstimulation of the exocrine function of the pancreas with the cholecystokinin analogue, caerulein (4 nmol kg-1 h-1, i.v.), for up to 120 min. 3. Pancreatic oedema began to develop 10 min after the start of the caerulein infusion, reached a maximum within about 45 min, and then declined slightly. The development of the oedema parallelled the second phase of the caerulein-induced fall in blood pressure found in earlier experiments. No further extravasation of plasma proteins occurred during the 2nd hour of the caerulein infusion. The oedema formation was completely blocked in animals pretreated with the bradykinin receptor antagonist, Hoe 140 (100 nmol kg-1, s.c.). Pretreatment with aprotinin or soy bean trypsin inhibitor did not result in a significant inhibition of the oedema. 4. The haematocrit of animals with experimental pancreatitis showed a pronounced increase which started 10 min after the start of the caerulein infusion and reached maximal values at 60 min. The changes in haematocrit showed a reduction in total blood volume of 28% due to a 48% loss of plasma. This effect was completely blocked by Hoe 140. 5. In rats with caerulein-induced pancreatitis, there was a time-dependent increase in the activities of amylase and lipase in blood serum as well as in the pancreas. Pretreatment with Hoe 140 greatly augmented the caerulein-induced rise in enzyme activities in blood serum but potently attenuated it in the pancreas. The activities of trypsin in both the blood serum and the pancreas were below or near the limit of detection in all experimental groups.6. It is concluded that the second phase of hypotension in this model of acute pancreatitis is due to the liberation of kinins which cause a massive loss of blood plasma into the pancreas and into the retroperitoneal space. Activated enzymes are trapped in the pancreas, at least in part, by the oedema of the gland. Treatment with Hoe 140 prevents the oedema formation and greatly facilitates the egress of activated enzymes from the pancreas.

Acute Disease↗
PubMed1993

Comparison of direct versus indirect determination of zinc concentration in erythrocytes in euthyroid and hyperthyroid subjects.

Zinc concentration in erythrocytes is a suitable marker of peripheral tissue response to thyroid hormones. Therefore, the determination of erythrocyte zinc concentration has become an important marker for duration of preexisting hyperthyroidism in the clinical laboratory. We compared a new indirect erythrocyte zinc determination method with a commonly used direct method in 42 euthyroid and 14 hyperthyroid subjects. Zinc concentrations (median and range) obtained by direct and indirect methods were 172.8 (134.4-241.1) and 176.8 (143-243.9) mumol/l erythrocytes in the euthyroid group and 117.1 (71-141.9) and 118.5 (73-137) mumol/l erythrocytes in the hyperthyroid group. Values measured by the indirect method were slightly higher in both groups. Regression analysis showed a good correlation (r = 0.967, p = 0.0001). The influence of the anticoagulants, potassium EDTA and heparin, on erythrocyte and plasma zinc values was studied, and zinc concentrations in serum and plasma were compared. No statistically significant differences were found. Thus, the indirect determination of erythrocyte zinc concentration is a simple and rapid technique well suited for use in clinical laboratory work, yielding accurate and reliable results. For the indirect method reference concentrations were established in a collective of 102 thyroid healthy subjects. An erythrocyte zinc concentration of 176.3 +/- 23.9 mumol/l (mean +/- SD) was found with a cut-off limit of 138 mumol/l to hyperthyroidism.

Biomarkers↗
PubMed1993

Simple decomposition procedure for determination of selenium in whole blood, serum and urine by hydride generation atomic absorption spectroscopy.

A digestion procedure for selenium determination by hydride generation atomic absorption spectroscopy (AAS) in whole blood, serum and urine is described, it employs sulfuric acid, hydrogen peroxide and vanadium (V) sulfuric acid reagent solution. The method is rapid, uses no explosive reagents and can be performed at a constant temperature of 100 degrees C. Therefore, it is easily applicable in a routine clinical laboratory for a large amount of samples. The coefficient of intra-assay variation was 4.3-5.6%, the coefficient for inter-assay variation was 5-5.9% in the medium and high concentration range, and 5.8-8.6% in the low range. In analyzing several commercial reference materials our results showed good agreement with the target values. Analytical recovery by addition of sodium selenite and seleno-DL-methionine to samples ranged between 97 and 104%. The correlation between the described digestion procedure and the nitric, sulfuric and perchloric acid digestion procedure recommended by the International Union of Pure and Applied Chemistry showed good agreement for whole blood, serum and for urine. We determined selenium in serum (n = 58) and whole blood (n = 50) in a collective of healthy children from 1 to 5 years living in Styria, Austria. The low values in serum (35 +/- 11 micrograms/L) and whole blood (42 +/- 6 micrograms/L) at one year of life increased significantly to 48 +/- 13 mu/L (p = 0.033) and 55 +/- 6 micrograms/L (p = 0.004) at three years of life in serum and whole blood, respectively. The selenium concentration showed no further increase up to five years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Austria↗
PubMed1993

[Iodine content of infant food in Austria].

An adequate iodine supplementation is essential for the normal and intellectual development in premature birth and in newborns. The ceric arsenite reaction method modified by the authors was applied to examine whether a sufficient iodine content in milk samples of four manufacturers ensured the iodine supply of bottlefed preterms and fullterms. Only very few of 23 preparations examined contained the required iodine content recommended by the Food and Drug Nutrition Board of the National Academy of Sciences, the National Research Council of the United States, the European Society of Pediatric Gastroenterology and Nutrition, and the German Society of Nutrition. It could be demonstrated that the majority of the commercially available baby food-milk preparations contained insufficient quantities of iodine. To assure a sufficient iodine supply in this bottlefed group it would be necessary to add a varied quantity of iodine to formula milk or to prepare baby food with iodine containing mineral water. Moreover, manufacturers might use milk from cows fed with iodinated salt. The results show clearly that an improvement in iodine content of commercial baby food is essential for the cerebral development of solely bottlefed newborns.

Austria↗
PubMed1993

[TBG isoforms in the course of hyperthyroidism].

In 7 hyperthyroid patients on the one hand thyroxine-binding globulin (TBG) was determined by commercially available radioimmunoassay and on the other hand TBG-isovariants were established by means of isoelectric focusing. For assessment blood samples were taken upon admittance to our hospital and 2 and 4 weeks thereafter, respectively, during antithyroid drug treatment. A comparative series of 10 euthyroid subjects were equally evaluated. Both groups showed no significant differences of TBG values at onset and in the course of antithyroid treatment. However, TBG isovariants showed significant decreases in anionic bands (pH 4.25 to 4.45) whereas a significant increase in cathodic bands (pH 4.55 to 4.65) at onset of treatment compared to the euthyroid control group could be observed. During the course of antithyroid treatment the values of TBG-isobands reversed reaching the pattern of normal group. In contrast to the recent research by Hashizume et al. we observed no reduction in TBG level in hyperthyroid patients although a significant shift in the TBG isovariants could be established. Due to the antithyroid treatment prescribed, the TBG isovariants finally reached the normal pattern of euthyroid controls.

Female↗
PubMed1993

[Iodine content of thyroid tissue in the Styrian population].

The iodine concentration was determined in 89 thyroid tissue samples of post-mortem examination material of thyroid healthy persons in dependency to the age. Before the 22nd week little iodine is stored in the fetal thyroid gland (median and range: 24 micrograms/g wet weight [0 to 27 micrograms/g]). From the 23rd week on the concentration is significantly higher (p = 0.004). There is a further increase of iodine concentration in the first 6 months of life, with a median concentration of 171 micrograms/g (75 to 808 micrograms/g). With a median of 599 micrograms/g (464 to 699 micrograms/g) the iodine concentration in the second year of life is comparable with that of adults (640 micrograms/g [218 to 2772 micrograms/g]). From the 60th year of life the median concentration is 462 micrograms/g (155 to 2100 micrograms/g), but this decrease is not statistically significant. Additionally the iodine concentration was determined in 7 topographically defined regions of 28 thyroid glands. The median iodine concentration did not differ in the 7 regions, but the iodine content in one and the same thyroid gland differed from region to region. Therefore in the healthy thyroid gland no regions exist, which have generally stored less iodine than others. However, no conclusion can be drawn from the iodine concentration of one biopsy to the whole iodine concentration of the organ.

Adolescent↗
PubMed1991

Simple determination of iodine in small specimens of thyroid tissue.

This work describes a simple photometric determination of the iodine concentration in thyroid tissue, a method based on the well-known catalytic Sandell-Kolthoff reaction. The modified ceric arsenite reaction is very sensitive and does not require complicated laboratory equipment. It can be performed in any routine clinical laboratory if instructions are followed strictly. By means of this method iodine concentration can be determined even in small specimens, for instance puncture samples of thyroid tissue or thyroid glands of small animals (mouse). Previous to the analysis, the tissue is digested in a mixture of sodium chlorate and perchloric acid at 100 degrees C. Using this manner of digestion between 94 and 110% of iodine in the sample were recovered. Comparison with neutron activation analysis showed excellent agreement of the obtained values.

Humans↗