Norepinephrine turnover and metabolism in rat brain after long-term administration of imipramine

The rate of disappearance of intracisternally administered tritiated norepinephrine from rat brain is decreased after a single dose of the tricyclic antidepressant imipramine. During long-term administration of imipramine, however, the rate of disappearance of tritiated norepinephrine from brain gradually increases, and there is a concurrent decrease in the content of endogenous norepinephrine in brain. These findings may help to explain why antidepressant effects are observed clinically only after long-termn treatment with imipramine.     

Hematuria following administration of ethanol

Hematuria, with some erythrocytes also appearing in the urine, was observed in male albino rats given 20 percent and 40 percent ethanol in lieu of drinking water for several weeks. However, the amounts of hemoglobin in the blood of the treated group did not change relative to those of the control group; this finding indicates that the degree of hematuria was not sufficient to produce an anemia.     

Angiogenic properties of Kaposi's sarcoma-derived cells after long-term culture in vitro

Cells derived from lung biopsies and pleural effusions from AIDS patients with Kaposi's sarcoma (KS) of the lungs were established in long-term culture with the aid of conditioned medium from HTLV-II-transformed T cells (HTLV-II CM). These AIDS-KS cells were similar to the so-called spindle cells in KS lesions and had some of their features. They produced factors that supported their own growth (autocrine) and the growth of other cells (paracrine), including umbilical vein endothelium and fibroblasts. That the AIDS-KS cells also expressed potent angiogenic activity was demonstrated by the chorioallantoic membrane assay and by subcutaneous inoculation of AIDS-KS cells into nude mice, which resulted in the development of angiogenic lesions composed of mouse cells and showing histological features similar to those of human KS lesions. These data suggest that AIDS-associated KS and possibly other types of KS may be initiated by signals that induce the growth of particular cells (spindle cells of lymphatic or vascular origin) and the expression of autocrine and paracrine activities.     

17种植物醇提物体外抗松木蓝变菌活性的研究

采用菌丝生长速率法对17种植物乙醇提取物进行体外抗松木蓝变菌——可可球二孢活性研究,结果表明:黄荆、马尾松、阴香、湖北海棠、羊耳菊等5种植物提取物对可可球二孢具有明显的抑制活性,且抑制率随浓度的升高而增强,其中马尾松、阴香、湖北海棠抑制效果增强最明显,在10 mg/mL的药剂浓度下分别达到69.96％、87.30％和66.07％,是抗可可球二孢引起的木材蓝变的植物源药剂开发潜力植物,可为进一步筛选具有较高抑制活性的植物源、新型、无污染的防木材蓝变剂提供科学依据.     

Decreased hippocampal inhibition and a selective loss of interneurons in experimental epilepsy

The occurrence of seizure activity in human temporal lobe epilepsy or status epilepticus is often associated with a characteristic pattern of cell loss in the hippocampus. An experimental model that replicates this pattern of damage in normal animals by electrical stimulation of the afferent pathway to the hippocampus was developed to study changes in structure and function that occur as a result of repetitive seizures. Hippocampal granule cell seizure activity caused a persistent loss of recurrent inhibition and irreversibly damaged adjacent interneurons. Immunocytochemical staining revealed unexpectedly that gamma-aminobutyric acid (GABA)-containing neurons, thought to mediate inhibition in this region and predicted to be damaged by seizures, had survived. In contrast, there was a nearly complete loss of adjacent somatostatin-containing interneurons and mossy cells that may normally activate inhibitory neurons. These results suggest that the seizure-induced loss of a basket cell-activating system, rather than a loss of inhibitory basket cells themselves, may cause disinhibition and thereby play a role in the pathophysiology and pathology of the epileptic state.     

减产后贮木场的对策

对调产后的贮木场生产现状进行诊断，剖析了贮木场生产状况和存在的问题，找出了制约贮木场活力的因素，提出调产后贮木场经营措施，为贮木场管理提供对策。     

Lipoprotein uptake by neuronal growth cones in vitro

Macrophages that rapidly enter injured peripheral nerve synthesize and secrete large quantities of apolipoprotein E. This protein may be involved in the redistribution of lipid, including cholesterol released during degeneration, to the regenerating axons. To test this postulate, apolipoprotein E-associated lipid particles released from segments of injured rat sciatic nerve and apolipoprotein E-containing lipoproteins from plasma were used to determine whether sprouting neurites, specifically their growth cones, possessed lipoprotein receptors. Pheochromocytoma (PC12) cells, which can be stimulated to produce neurites in vitro, were used as a model system. Apolipoprotein E-containing lipid particles and lipoproteins, which had been labeled with fluorescent dye, were internalized by the neurites and their growth cones; the unmetabolized dye appeared to be localized to the lysosomes. The rapid rate of accumulation in the growth cones precludes the possibility of orthograde transport of the fluorescent particles from the PC12 cell bodies. Thus, receptor-mediated lipoprotein uptake is performed by the apolipoprotein B,E(LDL) (low density lipoprotein) receptors, and in the regenerating peripheral nerve apolipoprotein E may deliver lipids to the neurites and their growth cones for membrane biosynthesis.     

Glycerol metabolism in the human liver: inhibition by ethanol

Glycerol is metabolized predominantly in the liver, the first step presumably being phosphorylation to alpha-glycerophosphate. When ethanol is present in the blood the rate of glycerol uptake by the splanchnic organs is reduced to about one-third of the control value. At the same time glycerophosphate accumulates in the liver. Hepatic blood flow and oxygen consumption are not influenced by the combined infusion of glycerol and ethanol. The phenomenon may be connected with the increased concentration of the reduced form of diphosphopyridine nucleotide present in the liver during ethanol metabolism.     

Poliomyelitis in Monkeys: Decreased Susceptibility after Avoidance Stress

Eleven monkeys were subjected to avoidance stress for 24 hours followed immediately by intravenous inoculation with type I poliovirus. Twelve control monkeys not so stressed were similarly inoculated. Seven of 11 stressed animals survived the infection while only one of the controls lived and their average incubation period was significantly longer than the average for controls. The number of circulating lymphocytes decreased significantly in experimental animals during and immediately after exposure to stress.     

Excitation and inhibition of neuronal firing in visual cortex by reticular stimulation

The frequency of action potentials of about one-third of the neurons sampled in the striate cortex of awake rabbits was clearly modified by mild stimulation of the reticular core of the brain stem. Reticular stimulation often brought about enhancement of firing in units activated by light, while it usually had the contrary effect upon light-inhibited units.     

Lesion-induced sprouting in the rat dentate gyrus is inhibited by repeated ethanol administration

The effect of ethanol on hippocampal axonal sprouiting was studied with a histochemical technique for identifying acetylcholinesterase. Unilateral lesion of the entorhinal cortex in adult rats produced an increase in the density of acetylcho-linesterase staining in the outer molecular layer and a concomitant increase in the width of the pale-staining commissural-associational zone of the dentate gyrus. Other rats were given ethanol (11.3 +/- 0.45 grams per kilogram) for 2 weeks before and 9 days after receiving the lesion. Ethanol abolished the expansion of the commissural-associational zone. The effect of ethanol on sprouting axons suggests that it may inhibit recovery of function after brain injury.     

Hepatic microsomal enzymes in man and rat: induction and inhibition by ethanol

The feeding of ethanol increased significantly the activities of hepatic pentobarbital and benzpyrene hydroxylases in rats, and, in human volunteers, doubled pentobarbital hydroxylase activity. In vitro ethanol inhibited aniline, pentobarbital, and benzpyrene hydroxylases. These data may explain, at least in part, the increased tolerance of alcoholics to sedatives when sober, and the enhanced sensitivity to sedatives when inebriated.     

Frog cerebellum: absence of long-term inhibition upon Purkinje cells

Electrophysiological studies of the cerebellar cortex of the frog demonstrate a lack of long-term inhibition upon the Purkinje cells. This lack of inhibition correlates well with the absence of stellate and basket cells in the molecular layer of this cerebellum and strongly supports the idea that these interneurones are the agents responsible for the prolonged inhibition seen in the Purkinje cells of other species.     

Recovery of neuronal function after prolonged cerebral ischemia

Cats were submitted to complete cerebral ischemia by clamping the innominate and subclavian arteries and simultaneously lowering the systemic blood pressure. Neuronal function was assessed by recording the electroencephalogram and the anti- and orthodromic activation of the pyramidal tract. A full recovery of the pyramidal response and even of evoked electroencephalographic activity occurred after ischemia of more than 1 hour's duration.     

Intracellular injection of cAMP induces a long-term reduction of neuronal K+ currents

Intracellular signals that trigger long-term (24-hour) changes in membrane currents in identified neurons of Aplysia have been examined in order to understand the cellular mechanisms underlying long-term sensitization. Adenosine 3',5'-monophosphate (cAMP) was directly injected into individual sensory neurons to mimic the effects of sensitization training at the single cell level. Potassium currents of these cells were reduced 24 hours after injection of cAMP; these currents were similar to those reduced 24 hours after behavioral sensitization. These results suggest that cAMP is part of the intracellular signal that induces long-term sensitization in Aplysia.     

Progesterone administration in vivo stimulates release of luteinizing hormone-releasing hormone in vitro

The release of luteinizing hormone-releasing hormone (LHRH) from tissue from the mediobasal hypothalamic-anterior hypothalamic-preoptic area of prepuberal female rats was measured in a perfusion system. Measurements were also made of the concentrations of LHRH in these tissue fragments and of luteinizing hormone in serum obtained when the rats were killed. Four groups of immature rats were studied: intact, ovariectomized, ovariectomized and implanted with estradiol-containing capsules, and ovariectomized rats primed with estradiol and injected with progesterone. The release of LHRH from the tissue of ovariectomized animals was significantly less than that of intact females and was not modified when the ovariectomized rats received estradiol. However, there was a four- to fivefold increase in LHRH release from tissue of ovariectomized rats primed with estradiol when they were killed 6 hours after they received an injection of progesterone. The concentrations of LHRH in tissue and of luteinizing hormone in serum varied among groups and with the time of day that the animals were killed. The interactions among luteinizing hormone, gonadal steroids, and the photoperiod seem to set the appropriate conditions for neural processes triggering a complete and normal release of luteinizing hormone.     

Drug-induced teratogenesis in vitro: inhibition of calcification by different tetracyclines

Inhibition of calcification in embryonic bone rudiments was studied in the presence of several tetracyclines at three different concentrations. Different criteria for calcification and different concentrations of tetracyclines yielded parallel results and showed significant differences in the inhibitory action of the various compounds. The clear-cut results indicate that the test-system that was developed may be useful for the comparison of various teratogens under simplified controllable conditions.     

关于构建权力运行监督与制约长效机制的思考

治理权力运行中的腐败问题,关键环节是构建监督与制约的长效机制。要完善各项制度,强化党政组织内和群众的民主监督,深入开展持之以恒、行之有效的反腐倡廉教育,构建监控权力不想腐败、不能腐败、不敢腐败的长效机制,以推动反腐倡廉建设深入开展。     

Detection, stimulation, and inhibition of neuronal signals with high-density nanowire transistor arrays

We report electrical properties of hybrid structures consisting of arrays of nanowire field-effect transistors integrated with the individual axons and dendrites of live mammalian neurons, where each nanoscale junction can be used for spatially resolved, highly sensitive detection, stimulation, and/or inhibition of neuronal signal propagation. Arrays of nanowire-neuron junctions enable simultaneous measurement of the rate, amplitude, and shape of signals propagating along individual axons and dendrites. The configuration of nanowire-axon junctions in arrays, as both inputs and outputs, makes possible controlled studies of partial to complete inhibition of signal propagation by both local electrical and chemical stimuli. In addition, nanowire-axon junction arrays were integrated and tested at a level of at least 50 "artificial synapses" per neuron.     

Gut reactions of radioactive nitrite after intratracheal administration in mice

Intratracheal administration to mice of radioactive nitrite labeled with nitrogen-13 (13NO2-) (half-life, 9.96 minutes) in dosages that do not cause pharmacological perturbation reveals that oxidative and reductive reactions occur in different organs. Oxidation of 13NO2- to radioactive nitrate (13NO3-) predominates in the blood and liver. Reduction of 13NO2- occurs in those mice that harbor intestinal microflora; this reduction does not occur in germ-free mice. The intestinal reduction products include ammonium, glutamate, glutamine, and urea. With a detection limit of about 0.01 percent of the instilled nitrogen-13, no labeled nitrosamines were detected within 30 minutes. Reduced nitrogen-13 is transported out of the intensive into the circulatory system and appears in the urine along with 13NO3-. The biological half-period for 13NO2- destruction is about 7 minutes, and both oxidation and reduction products are formed.