Insulin-like immunoreactivity in the human brain

Summary The localization and regional distribution of insulin-like immunoreactivity (IRI) was studied in human brain autopsy material using the indirect immunofluorescence technique. A positive reaction for IRI could be observed in many neurons of the hypothalamus, the hippocampus, corpus amygdaloideum, medulla oblongata (especially within the nuclei of cranial nerves IX, X and XII), and the cerebral cortex, whereas the cerebellar cortex was lacking in immunohistochemically detectable insulin-like material. No nerve fibres containing polypeptides could be revealed. Additionally, the inuslin content of various brain regions was estimated by radioimmunosassay. Insulin concentrations in human nervous tissue were found to be elevated in comparison to blood plasma levels.The present investigation was supported by the HFR Neurobiologie und Hirnforschung and the HFR Diabetes mellitus und Fettstoffwechselstörungen of the GDR (Ministries of Higher Education and Health respectively) and the Finnish Ministry of Education     

Effects of suprofen and other prostaglandin synthstase inhibitors in a new animal model for myometrial hyperactivity

An model for studying factors related to dysmenorrhea and for evaluating drugs for their inhibitory effects on uterine contractility induced by arachidonic acid and prostaglandins has been developed. Intravenous administration of arachidonic acid and PGF₂α to guinea pigs during the late stage of the estrous cycle, induced dose related uterine contractions and an elevation in uterine basal pressure similar that seen in patients with dysmenorrhea. Pretreatment with prostaglandin synthetase inhibitors inhibited the response to arachidonic acid. The order of relative potency was suprofen (1) > indomethacin (0.65) > naproxen (0.52) > ibuprofen (0.43) > aspirin (0.31). The effectiveness of maximal response for suprofen was significantly greater than that of the other compounds tested. Simultaneous administration of suprofen with PGF₂α also blocked induction of uterine contractions, suggesting the possibility that suprofen also antagonizes PGF₂α receptor binding. Bradykinin also induced uterine constractions, an effect blocked by pretretment with suprofen. Finally, histochemical studies demonstrated stimulation of uterine catecholamine levels (norepinephrine) by arachidonic acid, PGF₂α and bradykinin. These effects were blocked by suprofen.These data suggest that suprofen, an analgesic prostaglandin synthetase inhibitor, may be of use in the clinical tretment of the uterine contractions associated with primary dysmenorrhea.     

Isolation of RNA polymerases from the water mold Achlya

The DNA-dependent RNA polymerases I, II, and III (ribonucleosidetriphosphate: RNA nucleotidyl-transferase, EC 2.7.7.6) from Achlya ambisexualis E87 (male), have been isolated. The highly purified RNA polymerase I was found to be composed of polypeptides with the following molecular weights (·10^-4): 18.5, 14, 11.8, 7.3, 6.1, 4.9, 4.4, 2.8. RNA polymerase II showed a 400-fold higher resistance against -amanitin than mammalian or higher plant RNA polymerase II.     

The role of energy in hyperthermia-induced mammalian cell inactivation: A study of the effects of glucose starvation and an uncoupler of oxidative phosphorylation

When cultured Chinese hamster cells were exposed to 43°C hyperthermia, effects due to glucose deprivation and to the presence of the uncoupler of oxidative phosphorylation, carbonylcyanide-3-chlorophenylhydrazone, during the 43°C treatment proved to be strongly accelerated compared to the effects at normal temperature (37°C). This strongly indicates that the availability of energy plays an important role in the response of these cells to hyperthermia. One of the reasons cells die after hyperthermia may be a lethal lack of energy. Cells heated before glucose deprivation were able to maintain viability for a longer period during deprivation than cells without the preheat treatment. As the cells might develop thermotolerance after the heat exposure, this suggests that cells in the thermotolerant state use energy in a more economical way.     

Direct in vitro evidence for different susceptibilities to 4-hydroperoxycyclophosphamide of antigen-primed T cells regulating humoral and cell-mediated immune responses to sheep erythrocytes: a possible explanation for the inverse action of cyclophosphamide on humoral and cell-mediated immune responses

Suppressor T cells of humoral immune responses, effector T cells mediating DTH, suppressor T cells of DTH, and helper T cells of humoral immune responses, all with specificity to SRBC, were produced in mice. The biologic activity was tested in adoptive transfer experiments. In vitro treatment with different doses of 4-hydroperoxycyclophosphamide (4-HPCy) yielded the result that the various activities tested were not uniformly sensitive to the action of this drug: Suppressor T cells of humoral immune responses and effector T cells mediating DTH were resistant to doses of 4-HPCy that eliminated the activities of suppressor T cells of DTH and helper cells of the humoral immune response. These findings help to explain the various effects cyclophosphamide has on the in vivo immune response and may help to form a basis for the rational manipulation of the immune response by drugs that selectively affect different subgroups of immune cells.     

Inhibitory effects of pergolide on peripheral adrenergic neurotransmission in spontaneously hypertensive rats

Intraperitoneal injection of pergolide (12.5–500 μg/kg) produced dose-related and sustained arterial hypotension in anesthetized spontaneously hypertensive rats (SHR) which was accompanied by bradycardia at higher tested doses. During the time frame of hypotension produced by pergolide (50 μg/kg, i.p.), diastolic blood pressure and cardiac rate responses to electrical stimulation of the sympathetic outflow in pithed SHR were attenuated, whereas comparable responses induced by exogenous norepinephrine were unaffected. Pretreatment of SHR with sulpiride abolished pergolide-induced hypotension and prevented its inhibitory effect on neurogenic vasoconstrictor responses. Sulpiride alone had no effect on responses to electrical stimulation or injected norepinephrine. Yohimbine or vagotomy plus atropine did not attenuate the hypotensive effect of pergolide while hexamethonium or pithing reversed it; increments in pressure produced by pergolide after each of the latter interventions were probably mediated by postsynaptic alpha receptors, since vasoconstrictor responses to pergolide (10?100 μg/kg, i.v.) in pithed preparations were attenuated by phentolamine.The data suggest that pergolide lowers arterial blood pressure and cardiac rate by inhibiting peripheral sympathetic nerve function through a dopaminergic mechanism. The probable site of action of pergolide is at presynaptic (neuronal) dopamine receptors which are known to mediate inhibition of neurogenic release of norepinephrine.     

Inhibition of peripheral adrenergic neurotransmission by lergotrile in spontaneously hypertensive rats

Intraperitoneal injection of lergotrile (0.5 mg/kg) produced arterial hypotension and bradycardia for 120 and 90 minutes, respectively, in anesthesized spontaneously hypertensive rats (SHR). During this time frame, lergotrile (0.5 mg/kg, i.p.) greatly attenuated diastolic blood pressure and cardiac rate responses to electrical stimulation (0.062-4 Hz) of the sympathetic outflow in pithed SHR, but had no significant effect on comparable increments in pressure and rate produced by exogenous norepinephrine (0.01–10 μg/kg, i.v.). Pretreatment of SHR with haloperidol (2 mg/kg, i.p.) prevented lergotrile-induced hypotension and partially reversed its inhibitory effect on neurogenic vasoconstrictor responses. Haloperidol alone had no significant effect on baseline arterial blood pressure or responses to sympathetic nerve stimulation. Administration of hexamethonium (20 mg/kg, i.v.) to SHR antagonized the hypotensive response to lergotrile (0.5 mg/kg, i.p.), although hydralazine (2 mg/kg, i.p.) still produced a marked reduction in pressure.These results suggest that lergotrile produces arterial hypotension and bradycardia primarily by inhibiting peripheral sympathetic nerve function through a dopaminergic mechanism. The probable site of action of lergotrile is at presynaptic (neuronal) dopamine receptors which are known to be inhibitory to neurogenic release of norepinephrine.     

Reversal of diabetes by isogeneic transplantation of cultured pancreatic islets

Pancreatic islets were isolated by collagenase digestion from female Wistar rats and cultured at 20 mmol/l glucose. The enhancement of Mg++ concentration from 0.8 mmol/l up to 5.3 mmol/l had a protecting effect on the glucose-induced insulin release in the subsequent short-time incubation and prevented the age-depending decrease of B-cell function. About 1,000 cultured islets injected into portal vein normalized the plasma glucose of streptozotocin-diabetic rats. The plasma glucose patterns during the glucose load were nearly identical to healthy controls. These findings suggest that the cultured islets maintain the ability to secrete insulin in response to glucose in vitro as well as in vitro and that such islets can reverse an experimentally induced diabetes.     

Zur sozialen Organisation des BienenfressersMerops apiaster

Zusammenfassung Beobachtungen zur sozialen Organisation wurden in einer Bienenfresserkolonie (16 Paare) in Nordost-Griechenland von April bis August 1979 vorgenommen:Die zeitliche Abstimmung der Brutaktivitäten wurde während der einzelnen Stadien des Brutzyklus ermittelt. Die Synchronisation verbesserte sich signifikant zwischen der Fertigstellung der Höhle und dem Beginn der Eiablage.Balzfütterungen und Kopulationen häufen sich wenige Tage vor der Eiablage, werden gegen Ende der Eiablage wieder seltener und treten danach nicht mehr auf.Jedes Paar verteidigt einen Abschnitt der Uferböschung, obwohl es darin nur die Höhle und wenige Sitzplätze benutzt. Territoriale Auseinandersetzungen treten vor allem zwischen angesiedelten Paaren und Neuankömmlingen auf. Obwohl die Angriffe um ein Mehrfaches häufiger von den Territoriumsbesitzern ausgehen, ziehen sich diese später aus einem Teil des Territoriums zurück, und ein neues Paar rückt nach. Diese Streitigkeiten halten nur wenige Tage an.

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On the social organization of the European Bee-eater(Merops apiaster)

Summary Several aspects of the social organization have been studied in a breeding colony (16 pairs) in North-eastern Greece from April until August 1979:Colony synchronization was measured at the beginning and at the end of nest-hole excavation, egg-laying and incubation. The degree of synchrony increased between the end of excavation and the onset of laying.The rates of courtship-feeding and copulation increased a few days before the first egg was layed and decreased again at the end of the laying period.Every pair defended a part of the river bank although it only used the burrow and one or some perches there. Territorial conflicts especially appeared between a settled and an intruding pair. Although the attacks were performed several times more frequently by the territory owners, that pair withdrew from a part of its territory and the other moved up. These territorial conflicts only lasted a few days.