Showing papers by "Free University of Berlin published in 1981"

The Role of Cell-Mediated Immunity in Bacterial Infections

Abstract: A. Macrophage-Dependent Resistance in the Absence of Specific Immune Responses.... 1223 B. Augmentation of Macrophage Numbers by Local Proliferation and Influx of Monocytes from the Blood 1223 C. Granuloma Formation 1224 D. Macrophage Activation 1224 E. The Genetic Basis of Mononuclear Phagocyte-Dependent Resistance ......... 1226 F. Role of Polymorphonuclear Leukocytes .... 1226

The nonexistence of 8-transitive graphs

Abstract: We prove that the inequalitys≦7 holds for finites-transitive graphs assuming that the list of known 2-transitive permutation groups is complete.

Effect of service-levels on order-points or order-levels in inventory models

Abstract: Obtaining the desired service-level is one of the most important problems in inventory control. The term ‘service-level’ has been interpreted in several ways. This paper presents a survey of the three most common service measures and the mathematical calculations pertaining to each.

The ultrastructure of the interface between a glass ceramic and bone.

Abstract: The interface of alkali-poor glass ceramic implanted in femora of male Sprague-Dawley rats shows soft tissue, chondroid, osteoid, and bone in connection with the implant. The ultrastructure of the interface with soft tissue mainly exhibits a corrosion process, during which the dissolution of the crystalline phase of the glass ceramic precedes the dissolution of the glassy phase. Macrophages are involved in this process phagocytosing debris of the glassy phase and removing as well as dissolving the remainders of the glass ceramic. Under circumstances not yet fully understood, the corrosion stops, and ground substance like material is deposited, which can be, at least partially, mineralized. After the disappearance of macrophages, chondroblasts, and/or osteoblasts lay down collagen fibrils and ground substance in which matrix vesicles are discernible, representing initial foci of mineralization. Areas with bone connection display collagen fibers and deposits of apatite crystals in close relationship to the bulk glass ceramic as well as small particles mainly derived from the glassy phase of the implant, providing the micromorphological substrate for the shearing and tensile strength of the interface between glass ceramic and bone.

Pharmacological interference with in vitro tests of thyroid function.

Abstract: Numerous drugs may cause changes in the serum concentrations of T4 and of T3. If such alterations are not recognized an incorrect diagnosis may result. In moderate degrees of hypo- and hyperthyroidism thyroid hormone levels may be spuriously normal, or the influence of pharmacological substances may lead to false diagnosis of thyroid disease in euthyroid patients. Since prediction of such alterations remains uncertain, it may be necessary to perform additional investigations when a potential artefact is recognized. On the other hand many pharmacological agents, especially those which interact with neurotransmitters, may influence TSH secretion, too. The TRH-test may show an increased or decreased TSH response, although complete suppression is only rarely seen during high-dose glucocorticoid treatment when low TRH doses are applied. Because the TRH-test gives such wide separation between different clinical states false interpretations are generally less likely than with drug-induced changes in T4 and T3 values.

Shake-up Excitations and Core-Hole Screening in Eu Systems

Abstract: X-ray photoemission (XPS) spectra of the Eu $3d$ and Eu $4d$ core levels in Eu metal and in divalent and trivalent Eu compounds exhibit splittings into two components, caused by the occurrence of $4{f}^{6}$ and $4{f}^{7}$ final-state configurations. The observed phenomena are described in terms of final-state shake-up and shake-down processes accompanied by a decrease, respectively, increase of the $4f$ occupation number. An extension of the Kotani-Toyozawa model to $f$ and $d$ states gives a consistent description of both processes.

On the neuropharmacology of harmane and other beta-carbolines.

Abstract: β-Carbolines have been recently proposed as candidates for the unknown endogenous ligand of the benzodiazepine receptor. Out of the β-carboline derivatives already found in the mammalian CNS, harmane is clearly the most potent inhibitor of benzodiazepine receptor binding. Therefore, it has been considered as possible endogenous ligand for this new receptor system. However, a certain degree of specificity might be a basic condition to accept the hypothesis of harmane as the endogenous ligand. Thus, the effects of harmane as well as other β-carbolines on several neurotransmitter receptor binding systems in vitro and on some neuropharmacological tests in vivo were investigated. Harmane developed the highest affinity towards the benzodiazepine binding site among all systems investigated. Its IC50-values for inhibiting opiate and muscarinic cholinergic receptor binding were about four times lower than those for dopamine and serotonin receptor binding but were about four times higher than that found for the benzodiazepine receptor binding. Norharmane exerted a remarkable displacing activity only at the benzodiazepine binding site. Harmine affected mainly the opiate and cholinergic muscarinic system, whereas tetrahydronorharmane turned out to be a potent inhibitor of serotonin and dopamine receptor binding. Doses of harmane needed to produce convulsions as indication of its possible benzodiazepine receptor agonistic properties are also sufficient to diminish nociception and decrease body temperature whereas the apomorphine-induced licking rate was affected at higher doses. The data demonstrate that harmane affects not only the benzodiazepine binding site but also other neuronal mechanisms. Furthermore, only minor changes of the β-carboline structure lead to substantially different effects. Therefore, the search for other β-carbolines with higher affinity for the benzodiazepine binding site as harmane seems to be promising.

Repertoire sharing and song-post distance in nightingales (Luscinia megarhynchos B.)

Abstract: The relationship was studied between song-post distances and the extent of vocal repertoire sharing in 34 territorial nightingales settling in six homogeneously structured habitats. Repertoires were compared on the basis of shared song types and distances were measured between nocturnal song posts of first-order and higher-order neighbours. Our results showed that male nightingales shared fewer song types with very close and more distant neighbours than with neighbours at intermediate distances. This distribution is explained by the interaction betwee repelling and attracting components, which depends on the distance between song posts.

Effect of inhibitors of GABA aminotransferase on the metabolism of GABA in brain tissue and synaptosomal fractions.

Abstract: Five inhibitors of the GABA degrading enzyme GABA-aminotransferase (GABA-T), viz., gabaculine, gamma-acetylenic GABA, gamma-vinyl GABA, ethanolamine O-sulphate, and aminooxyacetic acid, as well as GABA itself and the antiepileptic sodium valproate were administered to mice in doses equieffective to raise the electroconvulsive threshold by 30 V. The animals were killed at the time of maximal anticonvulsant effect of the respective drugs and GABA, GABA-T and glutamate decarboxylase (GAD) were determined in whole brain and synaptosomes, respectively. The synaptosomal fraction was prepared from brain by conventional ultracentrifugation procedures. All drugs studied brought about significant increases in both whole brain and synaptosomal GABA concentrations, and, except GABA itself, inhibited the activity of GABA-T. Furthermore, all drugs, except GABA and gamma-acetylenic GABA, activated GAD in the synaptosomal fraction. This was most pronounced with ethanolamine O-sulphate, which induced a twofold activation of this enzyme but exerted only a weak inhibitory effect on GABA-T. The results suggest that activation of GAD is an important factor in the mechanism by which several inhibitors of GABA-T and also valproate increase GABA concentrations in nerve terminals, at least in the relatively non-toxic doses as used in this study.

Achromatic vision in the honeybee at low light intensities

Abstract: 1. Dark adapted honeybees (Apis mellifera camica) were trained in a T-maze to discriminate spectral light stimuli (λ=533, 430, and 413 nm) from dark or from an achromatic white light stimulus. 2. Bees trained to discriminate a spectral stimulus from an equally bright white light respond to the spectral stimulus as if it were the white stimulus within a certain range of intensities. This range lies between the threshold for detection of light (the achromatic threshold) and that for determination of color (the chromatic threshold); it is termed the achromatic interval. Thus the detection of spectral stimuli has two thresholds; a lower one for the absolute detection of the stimulus and a higher one for the perception of color hue. The achromatic interval for wavelengths λ=533, 430, and 413 nm is≃1.5 log10 units of light intensity. 3. Trained responses to spectral stimuli disappear at high stimulus intensities. Also, bees can not be trained to spectral lights of high intensity (>2 log10 intensity units above color vision threshold). This bright light effect is attributed to the specific response function of the lamina monopolar cells. 4. Achromatic vision is explicable in terms of known characteristics of receptor and neural organization in the bee color vision system. It is concluded that bees pool output of all receptors from a single ommatidium in a neural strategy which produces an achromatic signal. Bees use this neurally derived achromatic signal for orientation at light intensities near visual threshold.

Neurophysiological background of central neural cardiovascular-respiratory coordination: basic remarks and experimental approach.

Abstract: This paper is comprised of a review of past contributions and their theoretical consequences and a presentation of new results in studies of the origin of sympathetic rhythms and tone. Two basic mechanisms are involved: a primary intracentral coupling with the main cardiovascular—respiratory rhythm (MCRR) generator and a secondary reflex coupling. It was found that the activity and rhythms of certain sympathetic efferents, such as the cervical sympathetic, are closely related to the MCRR. Other efferents, such as the renal sympathetics, are loosely linked and follow drives from other circuits in the genesis of their rhythms and tone. New experimental evidence is given that rhythmic and tonic activity in sympathetic nerves originates from several sources. Hence central respiratory—autonomic systems interaction is not explained by simplistic concepts.

Surgical therapy of hyperinsulinism

Abstract: Organic hyperinsulinism is rare: the incidence is 1:100,000. In newborns, often of diabetic mothers, there may be islet cell hyperplasia. Rare cases may require partial pancreatectomy. In adults, the condition is always due to an insulinoma.

Spontaneous dissecting aneurysm of cervical cerebral arteries. Report of six cases and review of the literature.

Abstract: Six cases of spontaneous dissecting aneurysm of the internal carotid and vertebral arteries are reported. The angiographic findings and the clinical aspects of this disease are described. The lesion is not as rare as generally assumed.

Concentration of metabolites of valproic acid in plasma of epileptic patients.

Abstract: Summary: With the help of synthetic reference substances, five metabolites of valproic acid (VPA) could be quantitated by gas chromatography in the plasma of 26 epileptic patients undergoing chronic therapy with sodium valproate. The products of β-oxidation, i.e., 2-en-VPA, 3-hydroxy-VPA, and 3-keto-VPA were found to be the major metabolites of VPA in plasma, whereas the intermediates of ω-oxidation, 4-hydroxy-VPA and 5-hydroxy-VPA, were present only in markedly lower concentrations. It was thus confirmed that in addition to the excretion of VPA as the glucuronide, β-oxidation is the preferred metabolic pathway of VPA in man. However, taking the anticonvulsant activity of the metabolites as derived from animal experiments into consideration, none of the metabolites found in human plasma seems to contribute markedly to the therapeutic effect of VPA. Thus, in most patients, VPA seems responsible for more than 90% of the antiepileptic activity during continued medication in man. RESUME En utilisant des substances synthetiques de reference, cinq metabolites de l'acid valproique (VPA) ont pu etre determines par chromatographie en phase gazeuse chez 26 patients epileptiques soumis a une therapeutique continue par le valproate de sodium. Les produits de β-oxydation, 2-en VPA, 3-hydroxy-VPA et 3-keto-VPA, s'averent etre les metabolites majeurs du VPA dans le plasma alors que les substances intermediates d'ω-oxydation, 4-hydroxy et 5-hydroxy-VPA, ne sont presents qu'a de tres faibles concentrations. Ceci confirme que, en plus de l'excretion du VPA sous forme glucuro-noconjuguee, la β-oxydation est la voie metabolique principale chez l'homme. Neanmoins, si l'on considere l'activite antiepileptique des metabolites par rapport a l'experimentation animate, aucun des metabolites detectes dans le plasma humain ne semble contribuer de facon primordiale a l'effet therapeutique du VPA. Par consequent, chez la plupart des malades, le VPA seul parait etre a plus de 90% responsable de l'activite antiepileptique observee chez l'homme lors de traitement chronique. RESUMEN Con la ayuda de sustancias sinteticas como referenda, se han podido cuantificar mediante cromatografia de gases, 5 metabolitos de acido valproico (VPA) en el plasma de 26 epilepticos sometidos a terapia cronica con valproato sodico. Los productos de la beta-oxidacion, es decir, 2-en VPA, 3-hidroxi-VPA y 3-ceto VPA se identificaron como los metabolitos mayores del VPA existentes en plasma mientras que los productos intermedios de la omega-oxidacion (4-hidroxi-VPA y 5-hidroxi-VPA) se detectaron solo con concentraciones muy reducidas. Asi pues, se ha confirmado que, ademas de la excrecion del VPA como glucoronido, la beta-oxidacion es la via metabolica preferida en el hombre. Sin embargo, considerando la actividad de los metabolitos como se deriva de los experimentos animates, ninguno de los que existen en el plasma humano contribuye, de modo importante, al efecto terapeutico del VPA. Asi pues, en la mayoria de los enfermos, el VPA parece ser responsable de mas del 90% de la actividad antiepileptica durante el tratamiento continuado en el hombre. ZUSAMMENFASSUNG Mit Hilfe synthetischer Referenzsubstanzen konnten 5 Metaboliten der Valproinsaure (VPA) durch Gas-chromatographie im Plasma von 26 epileptischen Patienten quantifiziert werden, die chronisch mit Nat-riumvalproat therapiert wurden. Die Produkte der Beta-Oxidation (2-en VPA, 3-Hydroxy-VPA und 3-Keto-VPA) wurden als Hauptmetabolite des VPA im Plasma gefunden, wahrend die Zwischenprodukte der ω-Oxidation (4-Hydroxy-VPA und 5-Hydroxy-VPA) nur in deutlich niedrigerer Konzentration vorkamen. Es wurde also bestatigt, das zusatzlich zur Ausscheidung des glukuronierten VPA die Beta-Oxidation den bevorzugten metabolischen Stoffwechselweg des VPA beim Menschen darstellt. Bedenkt man jedoch die antikonvulsive Aktivitat der Metaboliten, wie sie im Tierexperiment zu erkennen ist, so scheint keiner der Metaboliten, der im menschlichen Plasma gefunden wurde, wesentlich zur therapeutischen Wirkung des VPA beizutragen. Damit scheint VPA fur mehr als 90% der antiepileptischen Aktivitat wahrend kontinuierlicher Medikation bei Menschen verantwortlich.

Two‐dimensional electrophoresis of membrane and cytosol proteins of mouse liver and brain

Abstract: Membrane proteins and cytosol proteins from organs (liver, brain) of inbred mice were separated by two-dimensional electrophoresis (2DE). The 2DE technique revealed high resolution of complex protein solutions by staining the proteins. The 2DE patterns of membrane proteins showed about 660 protein spots (polypeptides) for both liver and brain. The protein patterns of the cytosols revealed about 800 polypeptides for the liver and about 680 for the brain. The membrane proteins and cytosol proteins of the 2DE patterns represented two protein populations specific for these two cell components. They matched in 7 % (liver) or 23 % (brain) of the total number of membrane protein spots. The matched spots represented dissociable membrane proteins rather than contamination of the isolated membrane fractions by cytosol proteins. Protein patterns of the same cell fraction but from the two different organs investigated contained more than 50 % organ-unspecific polypeptides. Several conditions of our 2DE standard procedure were reinvestigated to test the usefulness for our technique of some methodical steps employed in 2DE by other authors. We found that many steps often used in sample preparations impaired rather than improved the 2DE pattern. In particular, addition of SDS to the protein sample resulted in a considerable loss of proteins during isoelectric foucing. The 2DE itself could be simplified by omitting several steps such as prefocusing, equilibration of focusing gels, forming gel gradients, autoradiography. This has some implications for the development of 2DE to a routine method.

Effects of sleep deprivation on depressed patients of different nosological groups

Abstract: In a study of 80 patients who received 164 treatments with sleep deprivation, the following questions were addressed: Do depressive patients of different subgroups respond differently to sleep deprivation? what complications arise? does the same patient react in the same way to multiple treatments? are there differences between responders and nonresponders? Results indicate that: (1) Endogenous depressions (unipolar, bipolar, and involutional) and psychotic depressions in schizophrenic patients improve significantly the day after sleep deprivation. However, on the second day, after a night's recovery sleep, a significant improvement occurs in neurotic depressives, whereas the endogenous and psychotic depressions worsen again. (2) Schizophrenic patients with a postpsychotic depression respond as well to sleep deprivation as patients with bipolar depression. (3) Complications arise very rarely in sleep deprivation therapy. (4) Patients in all the diagnostic categories studied can respond very differently to multiple treatments with sleep deprivation. (5) Responders and nonresponders do not differ in age, sex, or psychopathological state before sleep deprivation, and psychotropic drugs have no apparent effect on the therapeutic response.