Die Bedeutung der Glutathionkonzentration der Erythrocyten für die Diagnose der Osteomyelofibrose

Zusammenfassung Bei 16 von 17 Patienten mit Osteomyelofibrose wurden in den Erythrocyten erhöhte Konzentrationen an reduziertem Glutathion nachgewiesen. Die Bestimmung des Glutathions kann als differentialdiagnostisch wertvolles Kriterium für die Charakterisierung der Osteomyelofibrose angesehen werden.

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Summary In 16 of 17 patients with osteomyelofibrosis the concentration of erythrocyte reduced glutathione was increased. It is concluded that the determination of erythrocyte glutathione is of differential diagnostic value in the characterization of osteomyelofibrosis.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.     

Incidence of chromosomal imbalances in advanced colorectal carcinomas and their metastases

Comparative genomic hybridization (CGH) was used to screen 54 advanced colon carcinomas. i.e., 24 primary tumors and 30 metastases, for chromosomal alterations. Using a sensitive statistical method for the determination of DNA imbalances and histograms for analysis of the incidence of changes, we identified the DNA over-representation of chromosome 20q as the most common alteration being present in 100% of cases. High incidence deletions were observed on 18q21-18q23 (96%), 4q27-4q28 (96%), 4p14 (87%), 5q21 (81%), 1p21-1p22 (72%), 21q21 (74%), 6q16 (72%), 3p12 (66%), 8p24-8p21 (66%), 9p21 (64%), 11q22 (64%), and 14q13-14q21 (64%). Further frequent over-representation was found on 7q12-7q11.2 (75%), 16p11-16p12 (70%), 19p13 (70%), 9q34 (67%), 19q13 (67%), 13q34 (64%), 13q13 (64%), 17q21 (59%), 22q11 (61%), 8q24 (57%), and 1q21 (57%). Pronounced DNA gains and losses being defined as regions in which the ratio profiles exceeded the values of 1.5 and 0.5, respectively, frequently colocalized with peaks of incidence curve. The use of difference histograms for the comparison of tumor subgroups as well as case-by-case histogram for the analysis of 15 paired tumor samples identified several of the above alterations as relevant for tumor progression and metastasis formation. The study identified additional loci and delineates more precisely those that have been previously reported. For comparative purposes, we have made our primary data (ratio profiles, clinicopathological parameters, histograms) available at the interactive web site http://amba.charite.de/cgh, where the incidence of changes can be determined at individual loci and additional parameters can be applied for the analysis of our CGH results.     

Ionic conductances of cultured principal cell epithelium of renal collecting duct

The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10^–6 mol/l) and bathed on either surface with isotonic HCO ₃ ^– -free Ringer's solution, the transepithelial voltage,V _te, varied between –21 and –72 mV (apical surface negative) while the transepithelial resistance,R _te, ranged from 0.4 to 1.5 kcm². By 10:1 step-changes in Na⁺ concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10^–6 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity ofV _te even at 10^–4 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba²⁺ (5 mmol/l). 10:1 reduction of apical Cl^– concentration strongly hyperpolarizedV _te with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl^–. In addition there may be a small Cl^– conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10^–7 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl^– concentration caused a biphasic change inV _te (initial depolarization, followed by repolarization) which indicates the presence of a large Cl^– conductance in the basolateral cell membrane. The latter was not inhibitable by 10^–7 mol/l NPPAB. Higher concentrations of this and of an other Cl^– channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents.Dedicated to Prof. Dr. H. Sitte, Homburg, FRG, upon his 60th birthday.     

Untersuchungen zur Behandlung der endogenen Hyperlipoproteidämie mit β-Pyridyl-carbinol

Zusammenfassung Es wird über erste Ergebnisse einer Therapie der Hyperlipoproteidämie mit einer Retardpräparation des ß-Pyridyl-carbinol (Ronicol retard®) berichtet. Neben einer ausgeprägten Senkung der Gesamtesterfettsäuren und des Cholesterins im Serum wurde ein Rückgang der Leberepithelverfettung erreicht. Als Wirkungsmechanismus wird neben der bekannten Hemmung der Acylierung durch Nicotinsäure eine Hemmung der Fettmobilisierung (Hemmung einer adrenalinsensiblen Fettgewebslipase) diskutiert.Versuchspräparat der Firma Hoffman-La Roche AG; inzwischen als Ronicol-retard im Handel.     

Verfahren zur automatischen Messung von Enzymkinetiken

Zusammenfassung Es wird ein neues Verfahren zur automatischen Untersuchung von Enzymkinetiken angegeben. Die Umsatzgeschwindigkeit einer Enzymreaktion in Abhängigkeit von jeweils einer veränderlichen Größe wird hierbei am durchlaufenden Reaktionsgemisch kontinuierlich gemessen und registriert. Unabhängige Veränderliche kann eine Konzentration (z. B. Substrat-, Coenzym-, Wasserstoffionenkonzentration) oder die Temperatur sein. Am Beispiel der Ermittlung einer Aktivitäts-pS-Kurve (Koordinaten:v=Umsatzgeschwindigkeit;pS=negativer Logarithmus der Substratkonzentration) wird das Verfahren im Einzelnen beschrieben. Unsere Methode eignet sich bisher zur Untersuchung von Enzymen, deren Umsatz durch Messung der Lichtabsorption erfaßbar ist. Als Beispiel werden Aktivitäts-pS-Kurven von Lactatdehydrogenase aus menschlichem Herzmuskel- und Leberhomogenisat sowie von Kaninchenmuskel-LDH gezeigt und die ermittelten Michaeliskonstanten angegeben.     

Analysis of gene expression patterns in small amounts of human ventricular myocardium by a multiplex RNase protection assay

 End-stage human heart failure is associated with changes in expression of steady-state messenger RNA (mRNA) levels. These changes correspond to alterations in protein levels and myocardial function and may have clinical implications regarding etiology, clinical state, or prognosis. However, analysis of mRNA levels in endomyocardial biopsies can be accomplished only by the quantitative polymerase chain reaction, which is difficult to standardize. The aim of the study was to evaluate whether the RNase protection assay is applicable to measure mRNAs of multiple genes simultaneously in small amounts of ventricular myocardium comparable to myocardial biopsies. Total RNA was prepared from left ventricular myocardium from terminally failing hearts with idiopathic (n=9) or ischemic cardiomyopathy (n=7) and from nonfailing control hearts (n=10). mRNA was measured by an optimized RNase protection assay for the β₁-adrenoceptor, the stimulatory G protein α-subunit (G_sα), phospholamban, the calcium ATPase of the sarcoplasmic reticulum (SERCA), β-myosin heavy chain (β-MHC), and the atrial natriuretic peptide (ANP). We extracted 10.7±2.1 μg total RNA from three myocardial biopsies taken in vitro. All of the six genes were measurable in duplicate in a total of 7 μg RNA. mRNAs of β₁-adrenoceptor, phospholamban, and SERCA were lower in failing than in nonfailing myocardium by 50%, 33%, and 42% respectively, whereas β-MHC and G_sα mRNAs were unchanged. mRNA of ANP was expressed at high levels only in the failing myocardium, providing a highly specific and sensitive marker for discriminating nonfailing and failing hearts. A direct comparison with ANP and G_sα levels obtained by Northern blot analysis with 7.5 μg total RNA showed a good correlation between the two methods. The RNase protection assay is thus a suitable method for simultaneous measurements of multiple mRNA levels in human myocardial biopsies. Changes in mRNA levels closely reflected those identified by other methods using larger amounts of RNA. Increased myocardial ANP mRNA levels determined by the RNase protection assay may serve as a molecular marker of heart failure. Received: 12 May 1997 / Accepted: 8 September 1997     

Heterogeneity in the complement-dependent bacteriolysis within the species of Borrelia burgdorferi

Sixteen Borrelia burgdorferi strains, including all three species, were compared in a colorimetric bactericidal assay for their ability to escape the complement-dependent bacteriolysis on incubation in normal human serum free of specific antibodies (NHS). The species B. afzelii was found to be serum resistant (EB1, EB3, FEM1, FEM2, Pko), whereas strains of the species B. garinii were found to be serum sensitive (1/B29, G1, G2, PSth, PBr, PTrob). Six strains, mainly B. burgdorferi sensu stricto, were only partially sensitive (Z25, 297, B31, PKa-I, PBi). All strains activated the complement cascade in NHS, whereas only four strains (G1, G2, PBr, PSth) could activate complement in the presence of EGTA-Mg. After complement activation, covalently bound C3 fragments (C3b, iC3b) were detected on serum-sensitive as well as serum-resistant borrelial strains. Heterogeneity, however, was observed between serum-resistant and serum-sensitive strains with respect to deposition of C6 and C9. Whereas serum-sensitive strains were strongly positive for C6 and C9 and were, therefore, killed by the terminal complement complex (TCC), serum-resistant strains were devoid of C6 and C9 on their cell surface. The serum resistance may, therefore, be due to an absent or only transient formation of TCC on the bacterial surface. Received: 17 September 1996     

Ectopic ACTH secretion due to a bronchopulmonary carcinoid localized by somatostatin receptor scintigraphy

We present the case of a 65-year-old woman with an adrenocorticotropic hormone (ACTH) secreting bronchopulmonary carcinoid. This patient showed the typical long history of Cushing's syndrome, including hypokaliemia, impaired glucose tolerance, high levels of ACTH and -endorphin, and coproduction of other peptides. At the onset of clinical symptoms in 1979 an adrenal adenoma was suspected, and left-sided adrenalectomy was performed. The symptoms soon recurred, and the diagnosis of ACTH-dependent Cushing's syndrome was made. As no ACTH-secreting tumor was found, the right adrenal was resected, and the patient was followed up regularly. Fourteen years later chest roentgenography and computed tomography revealed a para-aortic pulmonary lesion, which was suspicious for a bronchopulmonary carcinoid. ACTH and -endorphin were excessively, pancreatic polypeptide slightly elevated at that time. The final diagnosis was made using somatostatin receptor scintigraphy which confirmed the hormonal activity of the suspicious lesion; no additional focus was found. This method turned out to be not only a useful additional localization technique but also a promising tool for characterization and staging of a suspected ACTH-producing carcinoid. The tumor was resected curatively, and the diagnosis was confirmed histologically.Abbreviations ACTH adrenocorticotropic hormone - DST dexamethasone suppression test - CRH corticotropin-releasing hormone - SRS somatostatin receptor scintigraphy - CT computed tomography - MRI magnetic resonance imaging