PubMed Health⌕ Search

Biomedical subjects

W Petek

Publications and source records attributed to W Petek.

At least 19 recordsLinked to original sources
PubMed1997

Rapid, sensitive high-performance liquid chromatographic method for the determination of cyclosporin A and its metabolites M1, M17 and M21.

Cyclosporin A (CyA) and its metabolites seem to have nephro-, hepato- and neurotoxic side effects. Immunosuppressive therapy is a narrow path between the risk of rejection by underimmunosuppression and toxic organ damage by overdosage. Thus CyA dosage must be calculated to avoid the risks of organ rejection through underdosage and toxic organ damage through overdosage or accumulation of metabolites. In routine monitoring of CyA therapy, it can be important to measure not only the parent drug but also the metabolites. We describe a rapid and isocratic high-performance liquid chromatographic method for measurement of CyA and its metabolites M1, M17 and M21 in whole blood. CyA was detected by ultraviolet absorption at 212 nm with a CN analytical column maintained at 50 degrees C and recycling of hexane-isopropanol as mobile phase for improved long-term column stability and efficiency. The minimum detectable concentration of CyA and the three metabolites was 10 ng/ml blood. Our modified HPLC method for the determination of CyA and its metabolites is a simple (isocratic), rapid (the retention times were 7.1 min for CYD, internal standard, 8.9 min for CyA, 11.0 min for M21, 12.9 min for M17 and 16.3 min for M1) and economical method suitable for measuring the concentration of the major metabolite, M17, and for routine monitoring of CyA-treated patients.

Chromatography, High Pressure Liquid↗
PubMed1997

Microalbuminuria and borderline-increased albumin excretion determined with a centrifugal analyzer and the Albumin Blue 580 fluorescence assay.

We report a new automated fluorescence assay for determination of albumin in urine. The dye Albumin Blue 580 specifically binds to albumin with exhibition of strong red fluorescence. The albumin concentration is calculated from emission intensity at 616 nm (excitation at 590 nm) and a calibration curve. Two Cobas Fara programs cover working ranges of 2-200 and 1-50 mg/L with detection limits of 1.4 and 0.4 mg/L, respectively. Within-run CVs (n = 10) ranged from 1.7% (189 mg/L) to 8.9% (7.2 mg/L) for 2-200 mg/L and from 2.9% (43.3 mg/L) to 5.7% (2.3 mg/L) for the 1-50 mg/L range. A test of urine samples (n = 100) submitted to routine analysis gave results that agreed well with those by the Behring nephelometric assay: AB 580 = 0.922 (+/-0.010) BNA + 4.16 (+/-0.78). No interference was detected from other urine components, including several proteins and 46 drugs. The high specificity and sensitivity make the method ideal for determination of microalbuminuria. In addition, the method is fast, inexpensive, and well-suited for clinical laboratory application and thus may be used instead of immunoassays.

Albumins↗
PubMed1996

[Hypertrophic callus formation and craniocerebral trauma: early diagnosis and behavior of basic fibroblast growth factor].

Hypertrophic callus formation in patients with severe head injury leads to an early fracture consolidation, whereas in joint fractures the enhanced ossification can even end in ankylosis of the injured joint. It is already known that these ossifications can be at least partly prevented by non-steroid anti-inflammatory drugs. Therefore, serum parameters have been determined that could predict this phenomenon. The mean values for alkaline phosphatase (ALP) and its bone isoenzyme were significantly increased in patients with severe head injury and bone fractures as soon as the 2nd week (reaching peak values in the 3rd week after injury) compared with patients with isolated fractures or head injury only and with normal healthy subjects. Procollagen I (PICP) was significantly increased even in the 1st week, reaching its peak during the 2nd week after injury. Compared with the callus volume at the time of fracture consolidation the size was determined from the X-rays--it was even possible to predict the volume of callus with the aid of these serum parameters as early as in the first few weeks after injury. A possible link between head injury and the increased bone formation could be the basic fibroblast growth factor (bFGF). In our study, bFGF was determined in serum by an immunoassay (ELISA), and an unusual pattern of dynamic change was observed in the patients with head injury and bone fractures. Compared with patients with isolated bone fractures bFGF immunoreactivity was significantly increased in patients with brain and bone lesions even in the 1st week after injury, with further peaks in the 2nd, 4th and 7th-8th weeks, with sudden decreases in between. In patients with isolated bone fractures a transient increase of bFGF was observed only during the 2nd week after injury. A similar increase was also determined in the sera of patients with head injury only, but it lasted longer. Thus, a posttraumatic increase of the serum bFGF was induced by bone as well as by brain injury, but was not causally related with the growth-promoting effects of the sera, as was proven by an in vitro analysis of the effects of the patients sera on L929 fibroblast growth.

Adult↗
PubMed1995

Released PMN elastase: an indicator of postsurgical uneventful wound healing and early inflammatory complications. A contribution to the search for objective criteria in wound healing monitoring.

Monitoring of postoperative wound healing is important for the early diagnosis of postoperative infective complications in order to decrease morbidity. The purpose of this study was to search for a discriminatory time point between uneventful wound healing and early wound infections after operations for orthopaedic trauma using PMN elastase. This proteolytic enzyme is a biochemical marker for pathological granulocyte stimulation. The two groups of injured patients comprised persons with 'per priman' (pp) wound healing without complications--group 1 (N = 31)--and the early manifestation of a bacterial wound infection 'per secundam' (ps) during the healing phase--group 2 (N = 4). In group 1, surgical trauma was accompanied by an increase in PMN elastase levels reaching the maximum within the first 3 postoperative days; values returned to normal on day 10. In group 2 PMN elastase median levels showed recurring increases throughout. No normal values were observed. There was a highly significant difference (P < 0.01) on days 4 and 5 in group 2 compared with the control group 1. Since PMN elastase can be determined on an autoanalyser, and the enzyme is of proven discriminatory value, it is suggested that this marker should become part of the daily diagnostic routine in the care of the injured.

Adult↗
PubMed1995

Lipoprotein(a) serum concentration and apolipoprotein(a) phenotype correlate with severity and presence of ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: Serum lipoprotein(a) [Lp(a)] levels are genetically determined and considered to be an independent risk factor for atherosclerosis. The aim of this study was to provide a complete analysis of Lp(a) serum levels, apolipoprotein(a) phenotypes, and other lipid parameters for different forms of severity of symptomatic ischemic cerebrovascular disorders as well as for different stages of carotid atherosclerosis. METHODS: Lp(a) concentration, apolipoprotein(a) phenotype, triglyceride, low-density lipoprotein, high-density lipoprotein, and total cholesterol levels of blind-coded specimens as well as degree of carotid artery stenosis were assessed in a consecutive series of patients with ischemic cerebrovascular disease. We evaluated 265 male (34%) and female (66%) patients (mean age, 51 +/- 7.4 years) with transient ischemic attack (55.8%), prolonged reversible ischemic neurological deficits (28.3%), and cerebral infarction (15.9%) as well as 288 male (30%) and female (70%) control subjects (mean age, 51 +/- 7.1 years). All subjects were white. RESULTS: Lp(a), total, and low-density lipoprotein cholesterol were statistically significantly elevated in all patients compared with control subjects. Lp(a) correlated with the severity of symptomatic cerebrovascular disease and the degree of carotid stenosis. Logistic regression analysis revealed Lp(a) as the best single marker for the presence of cerebrovascular disease (P < .001) followed by high-density lipoprotein cholesterol (P = .003) and triglycerides (P = .049). With a cutoff of 20 mg/dL of Lp(a), the odds ratio for a subject to have had ischemic stroke with elevated Lp(a) was 20.3 and 23.7 depending on the method of the Lp(a) estimation, whereas the odds ratio when the sonography score was > 0 was 15.4. The investigation of the distribution of the apo(a) phenotypes revealed that 16.73% of the control subjects had major isoforms < or = 580 kD molecular weight (B, F, S1, S2) versus 42.65% of the patients' group (P < .001). These isoforms were also present in 14.71% of all individuals with a sonography score of 0 but in 52.30% of all individuals with a sonography score > 0 (P < .001). CONCLUSIONS: This case-control study shows that an elevated Lp(a) level is the primary factor associated with the presence of ischemic cerebrovascular disease and that the increased portion of the smaller-molecular-weight apo(a) isoforms in patients and individuals with a sonography score > 0 points toward an inherited predisposition for this disease.

Adult↗
PubMed1995

Comparison of the values of basic fibroblast growth factor determined by an immunoassay in the sera of patients with traumatic brain injury and enhanced osteogenesis and the effects of the same sera on the fibroblast growth in vitro.

In patients with severe traumatic brain injury, the early healing of fractures is accompanied by hypertrophic callus formation or heterotopic ossifications, which might even result in ankylosis of the affected joints. Analysis of the sera of patients with traumatic brain injury revealed post-traumatic dynamic changes of basic fibroblast growth factor immunoreactivity, similar to those observed during fracture healing associated with enhanced osteogenesis. The aim of this study was to determine whether such changes in basic fibroblast growth factor concentrations could be related to the phenomenon of enhanced osteogenesis. Basic fibroblast growth factor immunoreactivity was determined (using an IEMA kit) in the sera of patients with traumatic brain injury and bone fractures (n = 8) and in the sera of patients with either traumatic brain injury alone (n = 10) or bone fractures alone (n = 7), and the effects of these sera on L929 fibroblast growth were analysed in vitro. The results did not prove a causative relationship between the changes of basic fibroblast growth factor immunoreactivity and in vitro growth promoting effects of the sera. However, it is apparent that, in addition to changes in the growth-promoting activity and basic fibroblast growth factor concentration of serum, other as yet unknown post-traumatic changes can cause enhanced osteogenesis.

Adolescent↗
PubMed1995

System identification of the low-dose kinetics of p-aminohippuric acid.

The renal clearance of p-aminohippuric acid, due to tubular secretion in addition to glomerular filtration, can only be determined by kinetic experiments. Maximal information can be gained from observed temporal marker concentration profiles by fitting dynamic mathematical models of the processes involved, such as absorption, distribution, and elimination, to the kinetic data. Thereby the values of the system constants, such as fractional elimination or fractional distribution rates, and their accuracy measures are determined by methods which are based firstly on measured time-dependent data elicited in an individual test object by perturbing inputs and secondly, on mathematical formulations of prior knowledge of the underlying physiological system. Such methods of model adaptation are called system identification. In this context a computer-based method of system identification and error estimation for the system constants of two-compartment models matched a dynamic concentration profiles of p-aminohippuric acid is presented. The method is used of single-injection experiments to demonstrate that such a technique is able to correctly estimate the clearance of p-aminohippuric acid if sufficiently long experimental protocols are chosen, and to ascertain the sufficient length of a protocol for an individual subject. The renal clearance of p-aminohippuric acid is known to exhibit concentration-dependence generally, but to achieve its maximal value when low doses are applied. The present study deals with the low-dose kinetics of p-aminohippuric acid.

Adult↗
PubMed1995

Determination of the glomerular filtration rate by identification of sinistrin kinetics.

A computer-based method of system identification and estimation of parameter variance for two-compartment models matched to dynamic sinistrin concentration profiles for the determination of glomerular filtration rate is described. Thereby a procedure for the judgment of the optimal sampling time horizon is presented. Since single-injection techniques are suspected of yielding systematic overestimation of the glomerular filtration rate, a method is demonstrated confirming that such a technique employing sinistrin kinetics can be used to correctly determine the glomerular filtration rate. The validation of the system parameters gained by the single-injection method is made through prediction of the concentration contour under a constant infusion regimen in the same subject on a different occasion. This was performed in healthy controls and in patients with various degrees of renal insufficiency. Upon consideration of the dependence of the clearance estimates and their variances on the protocol duration in test subjects examined from four to ten hours, an adaptive design of the protocol length is developed.

Adult↗
PubMed1994

[Scurvy after a suicide attempt by starvation].

A 29-year-old man was admitted to hospital, unconscious and with extensive bleedings in skin and muscles. For many weeks he had been practically starving himself with suicidal intent. Physical examination revealed signs of anaemia and gingivitis with hypertrophy of the tooth borders and bleeding gums, as well as bright blood on rectal examination. There were extensive ecchymoses and petechiae, especially in the legs. Some of the body hair was corkscrew-curly. Haemoglobin level was 7.2 g/dl, mean corpuscular volume 93 fl, reticulocyte count 29/1000. The Rumpel-Leede test was abnormal (60 petechiae/4 cm2), as were the vitamin C level (0.026 mg/dl whole blood) and the ascorbic acid tolerance test. As these findings indicated scurvy, vitamin C was administered, 1 g daily intravenously for 5 days, followed by 500 mg daily by mouth. Remarkable improvement was apparent as early as 72 hours after onset of treatment. The endogenous depression, the underlying cause of the suicide attempt, was treated with clomipramine. When the patient was discharged after 13 days his physical and mental state was much improved.

Adult↗
PubMed1994

Post-traumatic dynamic change of carboxyterminal propeptide of type I procollagen, alkaline phosphatase and its isoenzymes as predictors for enhanced osteogenesis in patients with severe head injury.

Patients suffering from severe head injury and fractures of long bones or large joints often show enhanced osteogenesis, with hypertrophic callus formation and/or heterotopic ossifications. The advantage of this phenomenon is early consolidation of the fractures. An extreme disadvantage is extensive periarticular calcification, resulting in complete ankylosis of the affected joint. In spite of numerous efforts aimed at clarifying the way in which severe head injury can influence osteogenesis at a distant site, this phenomenon is still not understood. The process, once started, seems irreversible, but if diagnosed in time, could be prevented with non-steroid anti-inflammatory drugs that inhibit development of heterotopic ossifications. The major prerequisite for testing this possibility is to define parameters of an early diagnosis of enhanced osteogenesis. Thus, the aim of this study was to test whether serum values of some parameters related to bone regeneration could allow an early prediction of enhanced ossification following bone fracture in patients with severe head injury. Samples of sera were obtained from three groups of injured patients: fractures of long bones or large joints only (n = 6), severe head injury only (n = 8), severe head injury and fractures of long bones and large joints (n = 7) and from a group of apparently healthy volunteers (n = 10). The values for alkaline phosphatase (ALP), the bone isoenzyme, and the carboxy terminal propeptide of type I procollagen (PICP) were significantly higher (5-20 times as high) in patients with severe head injury and bone or joint fractures than in any other group. Significantly increased concentrations of PICP were already found in the 1st week after injury, and those of ALP and of the bone isoenzyme increased during the 2nd week after injury. Results show that these parameters are helpful for an early diagnosis of enhanced osteogenesis and heterotopic ossifications in patients with severe head injury and bone fractures. Further studies are necessary to verify these findings, while analysis of reasons for the specific patterns of dynamic change of these parameters could lead to better understanding of the mechanisms underlying the uncontrolled bone formation.

Adolescent↗
PubMed1994

Basic fibroblast growth factor (BFGF) immunoreactivity as a possible link between head injury and impaired bone fracture healing.

Healing of fractures of long bones or large joints is often accelerated in patients with severe traumatic brain injury (TBI). However, in these patients an early fracture healing is accompanied by hypertrophic callus formation or heterotopic ossifications which might even result in an ankylosis of the affected joints. It seems that enhanced osteogenesis in patients suffering from TBI could be caused by some humoral factors, since the sera of these patients strongly promote the growth of osteoblast cells in vitro. However, humoral growth promoting factors which could perhaps induce enhanced osteogenesis are not yet identified. Hence, the aim of this study was to analyse if basic fibroblast growth factor (bFGF) could be related to the phenomenon of enhanced osteogenesis, since bFGF stimulates the growth of osteoblasts in vitro and could be found both in the brain and the bone tissue. For that purpose the values of bFGF immunoreactivity were determined in the sera of patients with TBI and bone fractures (n = 8) as well as in the sera of patients with either TBI alone (n = 10) or bone fractures alone (n = 7), during a period of three months after injury. Quantification of the bFGF immunoreactivity was done using the ELISA based on monoclonal antibodies raised against the recombinant human bFGF. The bFGF immunoreactivity values obtained were also compared with the values determined in the sera of normal, healthy persons (n = 9). In the group of patients with bone fractures alone only a transient increase of bFGF immunoreactivity (threefold above the normal values) was observed in the second week after injury. A similar increase of the values of bFGF immunoreactivity was also determined in the sera of patients with TBI only, but it lasted longer (from the 1st until the 7th to 8th week after injury). In the case of patients with TBI and bone fractures a specific pattern of post-traumatic dynamic change of the values of serum bFGF immunoreactivity was observed. Namely, the increase of bFGF immunoreactivity (up to seven-fold above the normal values) was determined even during the first week after injury. Afterwards, periods of high values of bFGF immunoreactivity observed during the 2nd, 4th and the 7-10th weeks after injury were interrupted by sudden decreases even to the normal values (during the 3rd and the 5-6th week after injury).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1993

Determination of renal clearance of neopterin by a pharmacokinetic approach.

Pharmacokinetic modelling was used to determine the glomerular filtration rate and tubular secretion of neopterin, a marker for cellular immune activation. The method involves parameter identification employing the transient venous plasma concentration profiles of marker substances. By combined i.v. injection of neopterin and inulin which is excreted exclusively via glomerular filtration, neopterin was shown to be excreted in addition to glomerular filtration, by tubular secretion: clearance of inulin, 112 (S.D. 2.2) ml/liter; clearance of neopterin, 499 (S.D. 79.7) ml/min. A pilot experiment using in addition p-amino hippuric acid suggests that neopterin and p-amino hippuric acid may employ the same carrier system for tubular secretion.

Adult↗
PubMed1993

Detection and evaluation of persisting stress-induced hormonal disturbances by a post stress provocation test in humans.

Eighteen healthy army officers were subjected after prolonged rest to exhaustive ergometric work for about 15 minutes. Before and afterwards blood was taken from the cannulated antecubital vein for determination of free and sulfoconjugated catecholamines, cortisol, glucose, and white blood cell count. One week later, the same procedure was repeated with the same subjects with the difference that the probands underwent about 2.5 hours of difficult mountain climbing and a subsequent rest of 1.5 hours before ergometry. The most important results were: 1) total and bound fractions of catecholamines showed some significant differences between the first and second ergometry due to the previous mountain climbing stress; 2) serum cortisol did not increase after the first ergometry but did so significantly after the second ergometry due to the previous stress; low cortisol is not always indicative of the absence of stress; 3) the absolute number of white blood cells increased in both situations, correlated significantly with the severity of the stress and the individual increases were more person than situation specific and; 4) blood glucose remained unaffected in both situations. We conclude that a previous stress experience can affect a second stress response and that such a post stress provocation test can uncover persistent hormonal alterations. This procedure may be useful for the evaluation of inaccessible stress situations from subsequent stress measures.

Adult↗
PubMed1993

[Biochemical wound monitoring. PMN elastase in different healing stages after trauma surgery-orthopedic interventions].

Laboratory parameters are of proven value in the diagnosis of early postsurgical infections, since clinical aspects cannot always be clearly defined. Neutrophil granulocytes (PMN) are major inflammatory cells taking effect following ingestion and degradation of foreign material, such as bacteria and cell debris, for example after mechanical trauma. In patients who had undergone surgery we monitored the course of plasma PMN elastase in uncomplicated wound healing (n = 22), in uncomplicated wound healing associated with secondary infections (n = 6), and in defective wound healing (manifestation of a bacterial wound infection: n = 3; wound infection already manifest at the time of entry on study: n = 11). Surgical trauma was accompanied by an increase in PMN elastase and C-reactive protein (CRP) in all patients studied, reaching a maximum within the first 3 postsurgical days. When a bacterial wound infection became manifest during the course of healing there was a highly significant difference on the 4th postsurgical day (p < 0.01) compared with the group with uncomplicated healing. Since PMN elastase can now be determined automatically with an autoanalyser and a commercial kit and its discriminatory time point is as soon as 4-5 days after surgery, it is suggested that this marker should be determined routinely together with CRP in traumatology.

Adult↗
PubMed1992

Dissociation-enhanced lanthanide fluorescence immunoassay of lipoprotein(a) in serum.

Lipoprotein(a), a human serum lipoprotein structurally related to low-density lipoprotein (LDL), contains in addition to apolipoprotein B (apo B) apolipoprotein(a) [apo(a)], a glycoprotein with a strong homology to plasminogen. Lp(a) is a risk factor for coronary heart disease and ischemic cerebrovascular disease. Several immunological techniques are used to quantify Lp(a) in human serum, including radioimmunoassays, rocket immunoelectrophoresis, and enzyme-linked immunosorbent assays. Only the last method is suitable for large-scale clinical studies. We describe another solid-phase immunoassay, based on the dissociation-enhanced lanthanide fluorescence system Delfia (Wallac Oy), and outline the technical details. A polyclonal antiserum directed against Lp(a) was used as the capture antibody. Two kinds of detection antibodies were applied, a polyclonal antiserum against apo B and the polyclonal antiserum against Lp(a). The results agree excellently with the values estimated by rocket immunoelectrophoresis. This assay is easily established, measures Lp(a) in a wide concentration range, and is suitable for screening large populations.

Enzyme-Linked Immunosorbent Assay↗
PubMed1990

[Iodine supplementation in the province of Styria].

As far back as 1898 the Austrian Nobel price winner Wagner von Jauregg was the first to recommend iodination of salt as prophylaxis against endemic goitre (prevalence 48%) and cretinism (greater than 10%). In 1923 he achieved in a voluntary iodine supplementation of 5 mg KJ/kg table salt, which only lasted for a number of years. It was in 1963 when finally a mandatory iodized salt prophylaxis was introduced at the rate of 10 mg KJ/kg. In this study the effect of 25 years of iodine supplementation is investigated: Endemic cretinism, hypothyroidism, and goitre in newborns disappeared generally and endemic goitre in pupils was significantly reduced. However, due to epidemiological studies at elementary and secondary schools and army recruitment examinations we still found out endemic goitre grade I (according to WHO) mainly in female juveniles. Examinations were done by palpation, ultrasonography and urinary iodine excretion. In the above as well as in the urine of newborns and in mother's milk the iodine content was significantly lower than in iodine rich countries. Consequently a higher iodination of salt at the rate of 20 mg KJ/kg was recommended by the Austrian Society of Nuclear Medicine in 1985. This suggestion was taken up by the Austrian authorities and it will finally be instituted by law in May 1990 for the benefit of coming generations.

Adolescent↗
PubMed1990

Serum selenium levels in distinct manifestations of coronary artery disease.

The trace element selenium plays an important role in the oxidation of lipids and is therefore closely associated with atherosclerosis. In a series of 49 unselected male patients having undergone coronary angiography, the serum selenium level was determined using flameless atomic absorption spectrometry (Zeeman technique), and compared to a standard (Seronorm; Nycomed). In the whole series the serum selenium levels were markedly decreased with no significant difference between patients with or without coronary artery disease. The severity of the coronary artery disease (CAD) did not correlate with the selenium level. However, patients with prior myocardial infarction had a significant higher selenium level than those without. Thus, the level of selenium does not appear to be a marker or a risk factor for coronary artery disease.

Aged↗