Thyroid gangliosides with high affinity for thyrotropin: potential role in thyroid regulation

Thyroid cell membranes contain a multiplicity of gangliosides, some of which inhibit thyrotropin binding to thyroid membranes. The most potent inhibitor is a ganglioside which is present in only trace amounts and appears to have a novel structure. Thyroid gangliosides may play a role in relaying the hormonal message to the thyroid cell.     

Axonal transport of gangliosides in the goldfish optic nerve

Radioactive glucosamine and N-acetylmannosamine injected into the goldfish eye are incorporated into gangliosides that undergo rapid axonal transport to the optic nerve terminals. All ganglioside fractions are labeled. These data provide the first evidence that axonal transport has a role in neuronal ganglioside function and metabolism.     

Nucleohistone dissociation by ganglioside micelles

The sialic acid-containing glycosphingolipids known as gangliosides can reverse the heat stabilization of DNA by histones. The ability of pure mono-and disialogangliosides to dissociate reconstituted nucleohistone is directly dependent on their sialic acid content; they are effective in concenitrations above their critical micelle concentration.     

Direct evidence that endogenous GM1 ganglioside can mediate thymocyte proliferation

The B subunit of cholera toxin, which is multivalent and binds exclusively to a specific ganglioside, GM1, was mitogenic for rat thymocytes. When exposed to the B subunit, the cells proliferated, as measured by 3H-labeled thymidine incorporation. Mitogenesis depended on the direct interaction of the B subunit with GM1 on the surface of the cells. This demonstrates that endogenous plasma membrane gangliosides can mediate proliferation in lymphocytes.     

当前农村凋敝状况的调查与分析——以鄂西南百福司土家族社区为个案

以鄂西南百福司土家族社区为个案,对当前农村人力资源亏空、村落虚空、田园荒芜等凋敝状况进行了调查分析。认为当前农村凋敝的原因表现在3个方面:一是农业的效益差、农民收入低,而在城市务工收益高见效快。这种比较利益驱使农民弃农厌农,越来越多的农户举家外出,甚至一些村庄出现了举村外出的现象,结果是大量耕地因无人耕种而荒芜,村落社区也因此而日益破败、萧条。二是农村市场发育不良,农产品不能顺利地进入市场。三是农业与非农业、农村与城镇在收入分配上的悬殊使人们不再珍视土地。土地不再是农民的最爱,农业、农村失去了往昔的吸附力和凝聚力。     

钢制拱顶油罐罐壁凹陷原因分析

针对某石油三厂的两座5000m3拱顶柴油罐在开泵倒油时发生罐壁凹陷的问题,对钢制拱顶油罐罐内油气空间压力变化进行了定性和定量分析,并根据短桶压力容器有关理论对其进行数据处理。分析结果表明,油罐的内外压差大于油罐失稳时的临界压力是导致油罐罐壁瞬间凹陷的主要原因。     

Growth hormone responses to L-dopa in depressed patients

Plasma human growth hormone responses to oral administration of 500 milligrams of L-dopa were analyzed in three groups of subjects: normals, age 20 to 32; normals, age 48 to 68; and unipolar depressed patients, age 45 to 68. While only 7 percent of the young normals had deficient human growth hormone responses to this stimulus, 36 percent of the older normals and 77 percent of the depressed patients failed to have adequate responses, suggesting an effect of age and a further effect of depressive illness. Because the release of human growth hormone appears to be closely related to brain catecholamine metabolism, the deficient responses in the depressed patients may provide further support to the concept of a neurochemical defect in depressive illness.     

罗坎柑橘高接换头品种改良

由于罗坎柑橘的果实品质一直停滞不前,以至于曾经辉煌一时的罗坎柑橘一蹶不振,果品滞销,果农沮丧。为转变这一不良局面,镇雄县采取高接换头的方式对罗坎柑橘进行品种改良。共换接塔罗科血橙品种接穗20000个,改良罗坎柑橘4900株,惠及果农186户。换接第二年试果,新枝试果品质优良,重新燃起了果农对柑橘产业发展的新希望。     

Vascular Smooth Muscle: Dual Effect of Calcium

The first part of the contractile response of rabbit aorta to epinephrine is depressed by elevation of calcium concentration; the second is potentiated. These observations suggest that the rate-limiting factor for the former is membrane excitability (depressed by increased calcium), while that for the latter is the role that calcium plays in coupling membrane excitation with the development of tension by the contractile protein (a function that is augmented by increased calcium).     

Soil-water potential: direct measurement by a new technique

Current methods of measuring the potential of water in soil are inadequate. It is proposed to depress the reference free energy of water by a predetermined amount from the standard level of pure free water at atmospheric pressure by use of a solute. The specific free-energy difference of soil water from the depressed reference can be measured as a pressure.     

Urinary adenosine 3',5'-monophosphate in the switch process from depression to mania

Marked elevations of urinary adenosine 3',5'-monophosphate occurred on the day of rapid switch from a depressed into a manic state in patients with manic-depressive illness. It is suggested that this increase might serve a trigger function for the process by which catecholamines are elevated during the manic phase of the illness.     

蛋鸡无豆粕日粮的试验研究

用玉米蛋白、豌豆蛋白、菌丝蛋白等全部替代蛋鸡日粮中的豆粕,并经特制预混料添加剂调整营养,其产蛋率与豆粕日粮差异不显著(P>0.05),而每Kg无豆粕日粮比豆粕日粮降低成本3.22％(0.05元),每Kg蛋的饲料成本降低5.83％(0.20元)。     

UV-B增强对作物生产影响的研究回顾与展望

大气平流层臭氧耗损引起的地表紫外辐射(UV-B)增强是气候变化问题之一。UV-B辐射增强对作物生长、生理代谢、产量及品质的影响受到人们普遍关注。通常借助两种方法开展模拟试验研究,即平方波模型法和太阳追踪模型法。UV-B辐射增强引起作物生长受阻、分蘖数减少、株高下降、叶面积和叶绿素含量下降、光系统Ⅱ受抑、光合效率降低;UV-B辐射增强导致活性氧代谢失衡、叶片气孔器受到破坏、叶绿体结构变形、基粒片层排列紊乱;UV-B辐射增强使作物有效穗数、穗粒数、千粒重下降,导致产量下降;UV-B辐射增强对籽粒蛋白质影响因作物、品种而异。未来应加强UV-B辐射增强影响作物内源激素代谢分子机制研究、区域和全球模拟及其应对措施研究。     

Species specific effect of acetylcholine on bivalve rectums

The pharmacology of acetylcholine and 5-hydroxytryptamine on the rectums of Katelysia rhytiphora and K. scalarina was found to be similar, in general, to that of other bivalves. However, while acetylcholine causes a fast twitch in the rectum of K. rhytiphora, the activity and tone of the K. scalarina rectum are depressed except at high concentrations of the drug. The two species can be distinguished by these responses, and, therefore, these rectums are useful experimental objects for studying the physiology of molluscan visceral muscle.     

月季花药理研究概况

月季花是一种常见的中草药,具有活血调经、疏肝解郁、消肿解毒等功效.本文对月季花的药理作用进行了综述,其有效成分主要为以槲皮苷、山奈黄素为主的黄酮类及以没食子酸为主的萜醇类化合物,阐述了月季花在天然色素资源、天然保健品及医学临床上的应用,为进一步开发月季花的药用功效提供理论依据.     

Gamma-aminobutyric acid antagonism in visual cortex: different effects on simple, complex, and hypercomplex neurons

Intravenous bicuculline was used to examine how removing gamma-aminobutyric acid-mediated inhibition affects the visual response properties of single cortical neurons. Simple neurons were depressed and complex neurons showed increase in the vigor and range of responses. Hypercomplex cells were no longer inhibited by elongated stimuli. The results are consistent with present evidence concerning the origin and distribution of inhibitory connections within the cortex.     

双草醚对土壤呼吸作用及土壤酶活性的影响

通过模拟试验研究了除草剂双草醚对土壤呼吸强度和土壤酶活性的影响。结果表明,双草醚施用初期刺激土壤呼吸作用但随后产生抑制作用,施用20d后,浓度愈大对土壤呼吸作用的抑制愈明显;双草醚轻微抑制土壤中过氧化氢酶活性,21d后基本恢复正常;双草醚对脲酶活性有刺激作用,且低浓度处理酶活性明显高于高浓度处理。统计分析结果表明双草醚属于低毒农药。     

Long-term amphetamine treatment decreases brain serotonin metabolism: implications for theories of schizophrenia

Long-term amphetamine administration to cats (a mean of 8.75 milligrams per kilogram twice daily for 10 days) produced large decreases (40 to 67 percent in serotonin and its major metabolite, 5-hydroxyindoleacetic acid, in all brain regions examined. This treatment also produced several behaviors that are dependent on depressed central serotonergic neurotransmission, and which normally are elicited exclusively by hallucinogenic drugs. Short-term amphetamine administration (15 mg/kg) did not produce these behaviors and resulted in small decreases in brain serotonin and no change in 5-hydroxyindoleacetic acid. These data are discussed in the context of monoamine theories of schizophrenia.     

Contracture and catecholamines in mammalian myocardium

Contractures induced by KCl are produced in cat ventricular muscle after depletion of catecholamine stores by previous treatment with reserpine or by selective blocking of adrenergic receptor sites with propranalol. Contractures are reproducible for 2 to 3 hours and are markedly depressed by the addition of epinephrine. The relaxation of contracture induced by epinephrine parallels the eftect of this compound of shortening the duration of the normal twitch. The failure of the normal mammalian myocardium to maintain tension in solutions of high KCI concentration appears to be related to the endogenous amounts of catecholamines in the tissue.     

Supraoptic neurosecretory cells: adrenergic and cholinergic sensitivity

Adrenergic and cholinergic agonists and antagonists were applied microelectrophoretically to over 700 neurons in the cat supraoptic nucleus, 20 percent of which were antidromically identified as neurosecretory cells. Norepinephrine uniformly depressed all sensitive cells. Acetylcholine caused both muscarinic depression and nicotinic excitation which were antagonized by atropine and dihydro-beta-erythroidine, respectively. These results support the hypothesis that norepinephrine and acetylcholine are directly involved in controlling the release of antidiuretic hormone.