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Biomedical subjects

M Zabel

Publications and source records attributed to M Zabel.

At least 55 records · Page 3Linked to original sources
PubMed2001

Preliminary immunohistochemical study of C cells of the thyroid and endocrine cells of the parathyroid glands in rats after prolonged exposure to cadmium.

The effect of cadmium (Cd) on the thyroid and parathyroid glands was examined following a 12-week exposure of rats to 5 or 50 mg Cd/dm3. Immunohistochemical methods were used to determine calcitonin (CT), calcitonin-gene related peptide (GGRP), parathormone (PTH), somatostatin (ST), synaptophysin (SPh) and neuron-specific enolase (NSE). Calcium and cadmium concentrations in the femoral bone were assayed. The animals exposed to cadmium showed attenuation of all reactions, which was most distinct after 50 mg Cd/dm3. Exposure-dependent cadmium accumulation and a decrease in calcium concentration in the femoral bone were noted.

Animals↗
PubMed2001

Immunolocalization of PTHrP in the European bison and pine vole testis and epididymis.

The present study deals with immunohistochemical localization of PTHrP in European bison and pine vole testis and epididymis. PTHrP immunoreactivity was observed in spermatogenic cells of seminiferous tubules in European bison and pine vole testis, with the strongerst reaction occurring in spermatozoa of pine vole testis and epididymal duct. We also observed PTHrP expression in vascular smooth muscle of epididymis and testis in both animal species, as well as slightly weaker reaction in endothelial cells of European bison epididymis. PTHrP was also expressed in the smooth muscle of the epididymal duct in European bison and pine vole. In conclusion, PTHrP is a multifunctional peptide showing both paracrine and autocrine action. Its presence in vascular endothelium and smooth muscle of testis and epididymis is connected with the regulation of vascular muscle tone, thus affecting blood flow in the vessels. PTHrP expression depends on a number of local factors. Moreover, we suppose that PTHrP also contributes to the proliferation and differentiation of spermatogenic cells.

Animals↗
PubMed2001

Techniques of molecular biology in morphological diagnosis of DNA and RNA viruses.

Recognition of virus structure and biology as well as the increasingly more complete understanding of pathogenesis in infectious diseases have been possible due to the rapid development of the molecular biology techniques. In the recent few years, most of the studies employing those techniques in diagnosis of infectious diseases concerned the detection of novel viruses, clarification of the virus role in diseases of unknown aetiology and determination of the effect of virus mutants on the course of the infection. The pathogenetic mechanisms of chronic infections, oncogenesis and fibrogenesis are continued to be studied. This paper presents the advantages of using in situ hybridisation in the microscopical diagnosis of viruses. Moreover, principal techniques of amplifying the level of virus detection (in situ PCR and its variants, Immunomax) have been described. Direct application of the Immunomax technique in combination with the in situ hybridisation and with immunocytochemistry have been illustrated with our own studies on tissue expression of selected DNA viruses (HBV and HCMV).

Animals↗
PubMed2001

Immunolocalization of PTHrP in the submandibular glands of three rodent species.

The present study deals with immunohistochemical localization of PTHrP in bank vole, pine vole and white mouse submandibular glands. PTHrP immunoreactivity was observed in epithelial cells of all ductal segments (intercalated, striated, interlobular and main excretory ducts) of the salivary glands in all the three animal species tested. We also found PTHrP expression in myoepithelial cells surrounding the mucous alveoli of submandibular glands in those animals. The reaction was less intense than that found in the epithelial cells of excretory ducts. We occasionally observed a very slight positive reaction for PTHrP in smooth muscle cells of small blood vessels. We also found PTHrP expression in the neurons of ganglion in the submandibular gland.

Animals↗
PubMed2001

Correlation of morphological alterations of light and electron microscopy in chronic type B and C hepatitis.

Chronic type B and C hepatitis involves inflammatory lesions of a variable intensity and variably advanced fibrosis. Considering current, progressively growing requirements for correct evaluation of lesions in liver biopsies, an attempt was made to appraise suitability of selected techniques for a broadened histopathological diagnosis. The lesions were evaluated at the level of light and electron microscopy. Material for the study consisted of liver biopsies obtained from adults and children (n = 60) with serological markers of chronic type B or type C hepatitis. Routine techniques of staining for light and electron microscopy, as well as the techniques of Brachet and Feulgen, were applied. HBcAg expression and HBV-DNA detection in children with chronic type B hepatitis were studied employing the avidin-biotin peroxidase complex (ABC) technique and in situ hybridisation with the ImmunoMax signal amplification. Slight or moderately intense inflammatory lesions (grading of 1 to 2 points) and a low level of fibrosis advancement (staging of 1 to 2 points) prevailed in the material, independently of the etiologic agent involved and age of the patient. Both in children and in adults, extensive lesions in the nuclear chromatin represented the common trait of chronic type B and type C hepatitis examined by light microscopy. Ultrastructural patterns confirmed the lesions and demonstrated virus-resembling particles in the cell nuclei. In HCV infection, hepatocyte cytoplasm contained tubular and horseshoe-shaped structures with lesions of mitochondria, while in HBV infection Dane's particles and tubular forms of HBsAg were detected. For cognitive reasons and due to frequently equivocal literature data, our data on ultrastructural lesions in chronic type C hepatitis seem to be of particular interest. Using the ImmunoMax signal amplification, we were able to diagnose HBV infection under light microscope and to define stage of the infection. Their sensitivity, specificity and relatively short time required for performing the tests makes them advisable in the routine diagnosis of the two infections.

Biopsy↗
PubMed2000

Rate-dependence of QT dispersion and the QT interval: comparison of atrial pacing and exercise testing.

OBJECTIVES: The study was done to determine whether variables of QT dispersion from the 12-lead electrocardiogram (ECG) are dependent on heart rate. BACKGROUND: The dispersion of the QT interval is under evaluation as a risk marker in patients at risk for ventricular arrhythmias. Assuming that a similar rate correction is necessary as for the QT interval itself, investigators have frequently reported QTc-dispersion values utilizing the Bazett formula. It is not known whether there is a physiologic basis for such a rate correction in the human heart. METHODS: In 35 patients referred for evaluation of ventricular arrhythmias, digital 12-lead ECGs recorded at various heart rates during submaximal exercise testing and again during atrial pacing upon electrophysiologic testing were submitted to computerized interactive analysis of several ECG dispersion variables. RESULTS: Data from 11 patients were excluded due to incomplete high-quality analysis possible at all heart rates. From the remaining 24 patients, a total of 193 ECG recordings at various heart rates (ranging from 76 +/- 17 beats/min to 117 +/- 14 beats/min during atrial pacing and from 78 +/- 18 beats/min to 110 +/- 14 beats/min during exercise testing) were available. A highly significant linear relationship with heart rate was found for both the QT interval and the Q-to-T-peak interval. By contrast, standard QT interval dispersion (QTmax - QTmin), the T-peak-to-T-end interval, and the average area under the T wave did not change with increasing heart rates. CONCLUSIONS: Dispersion of the QT interval and other ECG variables of dispersion of ventricular repolarization are independent of heart rate. Therefore, it is not necessary to rate-correct these measurements.

Electrocardiography↗
PubMed2000

Analysis of 12-lead T-wave morphology for risk stratification after myocardial infarction.

BACKGROUND: The stratification of post-myocardial infarction (MI) patients at risk of sudden cardiac death remains important. The aim of the present study was to assess the prognostic value of novel T-wave morphology descriptors derived from resting 12-lead ECGs. METHODS AND RESULTS: In 280 consecutive post-MI patients, a 12-lead ECG was recorded before discharge, optically scanned, and digitized. For the present study, 5 T-wave morphology descriptors were automatically calculated after singular value decomposition of the ECG signal. The total cosine R-to-T (TCRT [describes the global angle between repolarization and depolarization wavefront]) and the T-wave loop dispersion were univariately associated (P:=0.0002 and P:<0.002, respectively, U: test) with 27 prospectively defined clinical events in 261 patients (mean follow-up 32+/-10 months). Kaplan-Meier event probability curves for strata above and below the median confirmed the strong risk discrimination by TCRT and T-wave loop dispersion (P:<0.003 and P:<0.001, respectively, log-rank test). On Cox regression analysis, with the entering of age, left ventricular ejection fraction, heart rate, QRS width, reperfusion therapy, beta-adrenergic-blocker treatment, and standard deviation of R-R intervals on 24-hour Holter monitoring, TCRT (P:<0.03) yielded independent predictive value, whereas T-wave loop dispersion was of borderline independence (P:=0.064). Heart rate (P:<0.02), left ventricular ejection fraction (P:<0.02), and reperfusion therapy (P:<0.02) also remained in the final model. CONCLUSIONS: Computerized T-wave morphology analysis of the 12-lead resting ECG permits independent assessment of post-MI risk and an improved risk stratification when combined with other risk markers.

Analysis of Variance↗
PubMed2000

Predictive value of T-wave alternans for arrhythmic events in patients with congestive heart failure.

Measurement of microvolt level T-wave alternans in the surface electrocardiogram is a novel way to assess the risk of ventricular arrhythmias. Seven tests of arrhythmic risk, including T-wave alternans, were undertaken in 107 consecutive patients with congestive heart failure and no history of sustained ventricular arrhythmias; the patients were followed up for arrhythmic events during the next 18 months. Of the patients with events, 11 had positive and two indeterminate T-wave alternans results; there were no arrhythmic events among patients with negative T-wave alternans results. Of the seven tests, only T-wave alternans was a significant (p=0.0036) and independent predictor of arrhythmic events.

Arrhythmias, Cardiac↗
PubMed2000

Is bisacodyl absorbed at all from suppositories in man?

A HPLC procedure was developed to determine free BHPM in human plasma and urine after prior deconjugation of its glucuronides with glucuronidase. A single dose administration of a 10 mg bisacodyl suppository from Glaxo Wellcome, Poznań (Poland) to 16 volunteers each resulted in its low active metabolite (BHPM) plasma levels (10-55 microgram l(-1)) according to general assumptions. Its prompt laxative effect appeared within 56.6+/-10.8 min. The calculated serum half-life time of BHPM glucuronide excretion in urine was approximately 7.32+/-0.99 h. BHPM was excreted in urine in only 3. 36+/-0.52% if compared with the above bisacodyl rectal dose administered. Any relationship between BHPM plasma and/or urine levels and its laxative action does not occur. These results confirm the thesis that the laxative action of bisacodyl suppositories is initiated through a direct interaction of the drug in the rectum.

Adolescent↗
PubMed2000

Metal telluride clusters composed of niobocene carbonyl, telluride, and cobalt carbonyl units: syntheses, structures, and reactivity

Abstract: The reaction of [Cp#2NbTe2H] (1#; Cp# = Cp* (C5Me5) or Cp(x) (C5Me4Et)) with two equivalents of [Co2(CO)8] gives a series of cobalt carbonyl telluride clusters that contain different types of niobocene carbonyl fragments. At 0 degrees C, [Cp#2NbTe2CO3(CO)7] (2#) and [Co4Te2(CO)10] (3) are formed which disappear at higher temperatures: in boiling toluene a mixture of [cat2][Co9Te6(CO)8] (5#) (cat= [Cp#2Nb(CO)2]+) and [cat2][Co11Te7(CO)10] (6#) is formed along with [cat][Co(CO)4] (4#). Complexes 6# transform into [cat][Co11Te7(CO)10] (7#) upon interaction with HPF6 or wet SiO2. The molecular structures of 2(Cp(x)), 4(Cp(x)), 5(Cp*), 6(Cp*) and 7(Cp*) have been determined by X-ray crystallography. The structure of the neutral 2(Cp(x)) consists of a [Co3(CO)6Te2] bipyramid which is connected to a [(C5Me4Et)2Nb(CO)] fragment through a mu4-Te bridge. The ionic structures of 4(Cp(x)), 5(Cp*), 6(Cp*) and 7(Cp*) each contain one (4, 7) or two (5, 6) [Cp#2Nb(CO)2]+ cations. Apart from 4, the anionic counterparts each contain an interstitial Co atom and are hexacapped cubic cluster anions [Co9Te6(CO)8]2- (5) or heptacapped pentagonal prismatic cluster anions [Co11Te7(CO)10]n- (n=2: [6]2- , n=1: [7]-), respectively. Electrochemical studies established a reversible electron transfer between the anionic clusters [Co11,Te7(CO)10]- and [Co11Te7(CO)10]2in 6# and 7# and provided evidence for the existence of species containing [Co11Te7(CO),0] and [Co11Te7(CO)0]3-. The electronic structures of the new clusters and their relative stabilities are examined by means of DFT calculations.

Journal Article↗
PubMed2000

[Mechanism of induction and termination of ventricular fibrillation--significance of dispersion of ventricular repolarization].

It has been known for many years that ventricular fibrillation may be induced and terminated by electrical field stimuli. Recent experimental studies have shown that both fibrillation and defibrillation have a common electrophysiologic mechanism that is based on the interaction between the electrical field stimulus and ventricular repolarization. Ventricular fibrillation will be induced if the field stimulus is applied with the area of vulnerability, this area of vulnerability is defined two dimensionally by the shock coupling interval and shock strength, and is modified by the configuration of the shock. A field shock that is applied within the area of vulnerability causes heterogeneity of ventricular repolarization immediately after the shock (postshock dispersion), thereby enabling the development of circuit movements and reentry, and resulting in ventricular fibrillation. High energy shocks, however, that are applied above the area of vulnerability (i.e., above the upper limit of vulnerability) will not induce ventricular fibrillation due to homogeneous prolongation of repolarization and a resulting small postshock dispersion. In analogy, ventricular fibrillation will continue after unsuccessful low-energy defibrillation shocks due to high postshock dispersion, whereas a high-energy shock will synchronize ventricular repolarization, thereby causing small postshock dispersion and termination of ventricular fibrillation. This paper describes the relation between fibrillation, defibrillation and ventricular repolarization based on experimental findings. A possible clinical application of these findings is that the upper limit of vulnerability may be used as a surrogate for the defibrillation threshold. Thus, defibrillation threshold testing may not be necessary during future implantations of automatic cardioverter defibrillators.

Defibrillators, Implantable↗
PubMed2000

Subtypes of thymic epithelial cells defined by neuroendocrine markers.

The study attempted to define characteristics of thymic epithelial cells within rat thymus based on the expression of neuroendocrine markers. Using an immunohistochemical approach, the following markers were localised: protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE) and chromogranin A (ChA). It was shown that cells displaying immunostaining typical for individual markers reside in distinct regions of the thymus and represent subtypes within various populations of thymic epithelial cells. An immunoreactivity for PGP 9.5 was found exclusively in a subtype of cortical epithelial cells, located mostly within the inner zone of the cortex. On the other hand, NSE represented a marker of most epithelial cells located in the medulla. Few such cells which were negative for NSE proved positive for ChA. Among the cells with a strong reaction for NSE some cells also manifested a positive reaction for ChA. While the pattern of neuroendocrine marker distribution may reflect functional properties of thymic epithelial cells which might be different within distinct areas of the thymus, the differential expression of individual markers seems to reflect biological activity of the cells and/or distinct stages of their differentiation.

Animals↗
PubMed2000

Detection of DNA, mRNA and early antigen of the human cytomegalovirus using the immunomax technique in autopsy material of children with intrauterine infection.

The present study focuses on the immunomax technique in association with the avidin-biotin-peroxidase complex (ABC) technique and a non-isotopic variation of in situ hybridisation (ISH) for optimal microscopical detection of human cytomegalovirus (HCMV). The studies were performed on an archival paraffin material originating from five children deceased due to intrauterine infection. The results of immunocytochemical and hybridocytochemical studies, with or without amplification using biotinylated tyramine, were compared with the routine histopathological results and results obtained using the polymerase chain reaction (PCR). Early antigen (EA)-HCMV was demonstrated in approximately twice as many cells as detected in the routine staining and also in cells that seemed morphologically intact. The hybridocytochemical studies confirmed the presence of HCMV DNA in cells that were positive in the immunocytochemical tests and, in addition (using the ISH-immunomax technique), in cell nuclei of intact myocardial myocytes. In general, fewer cells manifested the presence of HMCV mRNA than the presence of HCMV DNA. The immunomax technique was found to be more sensitive than the techniques of classical immunocytochemistry or of ISH. The former technique permitted the documentation of a higher number of HCMV replication sites than could be detected using the latter techniques. However, the clinical course of HCMV infection or the cause of death of the children was not directly related to the intensity of HCMV expression in tissues.

Antigens, Viral↗
PubMed2000

[The analysis of estrogen and pregesterone receptors in leiomyomas cell in different phases of menstrual cycle].

The aim of a study was immunocytochemical analysis of estrogen (ER) and progesterone (PgR) receptors in uterine leiomyomas cells derived from patients who underwent an operation in three different phases: in the follicular phase of the menstrual cycle (12 cases), in the luteal phase (20 cases) and in the postmenopausal age (18 cases). The examined receptors reflect the tissue sensibility to activity of sex steroid hormones and play an important role in the pathogenesis of uterine leiomyomas. Performed studies showed that expression of ER and PgR does not depend on the phase of the menstrual cycle and that it seems to be similar like in the postmenopausal stage. In all groups PgR expression was significantly higher then the expression of ER. In the group of patients in which the surgery was performed during the luteal phase of the menstrual cycle was demonstrated negatively correlation (-0.4846) between the expression of ER in relation to the expression of PgR.

Female↗
PubMed2000

Immunocytochemical evaluation of reorganisation of keratinocyte cytoskeleton induced by change in Ca2+ concentration in culture medium.

Ca2+ level-induced changes in the arrangement of cytoskeleton of cultured keratinocytes were estimated immunocytochemically, by evaluating expression of specific cytokeratins, desmoplakin and tubulin. Keratinocytes were isolated from fragments of skin of dead human foetuses. Culture of epidermal cells was performed in two phases: phase I yielded cells of high proliferation abilities in serum-free Keratinocyte SFM of low Ca2+ level (0.03 mM); in phase II differentiated cells were obtained in Dulbecco medium of a high Ca2+ concentration (1.2 mM). Immunocytochemical evaluation of phase I and II cells revealed an array of differences which involved mainly expression and distribution of specific cytokeratins, distribution of tubulin, testifying to a different microtubule arrangement and distribution of desmoplakin and indicating a tendency to form desmosomes. The changes were induced by the changes in Ca2+ level in the culture medium.

Calcium↗
PubMed2000

S-100 protein immunoreactivity in mammalian testis and epididymis.

The present study deals with immunohistochemical localization of S-100 protein in mouse, bank vole and pine vole testis and epididymis. S-100 protein immunoreactivity was observed in the endothelia of capillaries and lymphatic sinusoids of pine vole testis. A reaction to S-100 protein of the same intensity as that noted in the endothelia of testicular capillaries was found in myoid cells of pine vole and bank vole seminiferous tubules. Moreover, a positive reaction to S-100 protein was observed in bank vole and mouse Leydig cells. In the epididymis, a weaker reaction to S-100 occurred in smooth muscles of pine vole and mouse epididymal duct. Despite difficult interpretation of physiological role of S-100 protein we suggest that it may be a part of the blood-testis barrier. It may also participate in the processes of transcytosis and contractility; its cellular expression is regulated by local factors. However, location of S-100 is not specific to the representatives of the same order.

Animals↗