m-Hydroxyphenylacetic acid formation from L-dopa in man: suppression by neomycin

The increased excretion of m-hydroxyphenylacetic acid in the urine of patients with parkinsonism being treated with L-dopa was reduced by gut sterilization with neomycin. The p-de-hydroxylation step is thus brought about solely by the action of gut flora; the pathway is unlikely to be involved in the events within the brain leading to the therapeutic benefit effected by L-dopa.     

农科论文中有效数字位数的准确表达

对农科论文中原始数据、计算数据等有效数字及其位数的准确表达进行了分析，认为不同类型数据的有效数字位数应依据相应的确定原则准确表达。     

Sleep: suppression of rapid eye movement phase in the cat after electroconvulsive shock

Electroconvulsive shock, administered for 5 to 7 days, reduced the daily rapid eye movement sleep time of seven cats to as little as 28 percent of base line levels. After day 4, eye movements during periods of cortical activation without tonic electromyographic activity were greatlyreduced. Although partially deprived of rapid eye movements for as long as 7 days, the cats showed no compensatory rise in rapid eye movement time during the recovery period, but controls equally deprived gave significant rebounds. Rapid eye movement time of anesthetized cats was not affected by current that usually produces con vulsions; it was lowered in animals convulsed with metrazol, but the same dosage of this drug, administered so as to avoid convulsions, had little eflect.It appears that some aspect of the convulsion is responsible for lowering the rapid eye movement time.     

Cognitive interaction after staged callosal section: evidence for transfer of semantic activation

Sensory and cognitive functions were assessed in a right-handed male before and after partial and complete callosal commissurotomy. After the initial posterior section was made, there was no evidence of interhemispheric sensory transfer, although the left hemisphere did have access to stimulus-related semantic and episodic information from the right hemisphere. After the callosum was completely sectioned, this exchange was no longer observed.     

手术间空气消毒后不同时间与手术切口感染的关系

观察手术间紫外线消毒后不同时间与手术切口感染的关系。方法从１９９１－１９９６年对１２间年监测达普通Ⅱ类空气标准的手术间及１２４１２例无菌手术病例刊物进行手术切口感染观察。以空气消毒后≤２ｈ内无毕手术的病例为甲组，〉２ｈ为乙组。结论空气消毒后时间的长短与手术切口感当关系密切。离消毒时间越长感染机会越大。     

Disposition of morphine in man

The disposition of morphine was investigated by means of radioimmunoassay after a single intravenous dose (10 milligrams per 70 kilograms) was administered to 10 adult normal male subjects who had not received other drugs for 2 weeks preceding the study. A multiphasic decline in serum concentrations of morphine occurred. Detectable blood concentrations of morphine, or of a metabolite, or of both persisted for 48 hours after a single intravenous dose.     

Variability of tooth formation in man

It has been demonstrated that liquid hydrocarbons, under the influence of gamma radiation, react with "high-surface sodium" to form metal alkyls. The nature of these metal alkyls has been determined, and possible mechanisms for their formation are discussed.     

Stress-induced suppression of immunity in adrenalectomized rats

Stress-induced suppression of lymphocyte stimulation by phytohemagglutinin was demonstrated in Isolated lymphocytes and in cultures of whole blood from adrenalectomized rats. The results demonstrate that corticosteroid independent mechanisms participate in the suppression of lymphocyte function by stressors. Stress-induced lymphopenia, however, was found to be adrenal dependent, indicating that the modulation of immunity by stress is complex and multidetermined.     

Temporary abolition of pain in man

In eight patients with intense chronic cutaneous pain, sensory nerves or roots. supplying the painful area were stimulated. Square-wave 0.1-millisecond pulses at 100 cycles per second were applied, and the voltage was raised until the patient reported tingling in the area. During this stimulation, pressure on previously sensitive areas failed to evoke pain. Four patients, who had diseases of their peripheral nerves, experienced relief of their pain for more than half an hour after stimulation for 2 minutes.     

Genetic suppression of polyglutamine toxicity in Drosophila

A Drosophila model for Huntington's and other polyglutamine diseases was used to screen for genetic factors modifying the degeneration caused by expression of polyglutamine in the eye. Among 7000 P-element insertions, several suppressor strains were isolated, two of which led to the discovery of the suppressor genes described here. The predicted product of one, dHDJ1, is homologous to human heat shock protein 40/HDJ1. That of the second, dTPR2, is homologous to the human tetratricopeptide repeat protein 2. Each of these molecules contains a chaperone-related J domain. Their suppression of polyglutamine toxicity was verified in transgenic flies.     

长江安庆江段春禁前后渔业生物多样性变化

1999-2004年4-6月份长江下游安庆江段渔获中出现鱼、虾、蟹种类共7目13科41种.春禁前(1999-2001)多样性特征值年间平均指标为:Shannon指数1.91,Margalef指数0.76,Pielou指数0.81,McNaughton指数0.53;春禁后(2002-2004)各指标为:Shannon指数2.42,Margalef指数1.38,Pielou指数0.79,McNaughton指数0.36.研究表明,春禁后安庆江段渔业生物群落结构正逐步趋于复杂化,多样性逐步回升.     

Osmolar control of prolactin secretion in man

To study the effect of changing serum osmolality on serum prolactin concentration 11 volunteers were given oral and intravenous hypotonic and hypertonic fluids. Mean serum prolactin fell to 10.5 percent of baseline after oral water loading and to 15 percent of baseline after intravenous hypotonic saline infusion. Conversely, mean prolactin rose to 417 percent of baseline after intravenous hypertonic saline administration. The correlation coefficient of simultaneously determined serum prolactin and osmolality was highly significant (P .001). Isoosmolar changes in extracellular fluid volume did not consistently affect the concentration of prolactin in the serum. Thus, prolactin may be involved in the physiologic regulation of osmolar balance and the kidney may be an important farget organ for prolaction.     

Skin-pigment regulation of vitamin-D biosynthesis in man

The known correlation between the color of human skin and latitude (Fig. 2) is explainable in terms of two opposing positive adaptations to solar ultraviolet radiation, weak in northern latitudes in winter yet powerful the year around near the equator. In northern latitudes there is selection for white skins that allow maximum photoactivation of 7-dehydrocholesterol into vitamin D at low intensities of ultraviolet radiation. In southern latitudes, on the other hand, there is selection for black skins able to prevent up to 95 percent of the incident ultraviolet from reaching the deeper layers of the skin where vitamin D is synthesized. Selection against the twin dangers of rickets on the one hand and toxic doses of vitamin D on the other would thus explain the world-wide correlation observed between skin pigmentation and nearness to the equator.     

弧脚梯形衬砌渠道抗冻胀及水力合理断面的分析

【目的】推导出适宜于季节性冻土区弧脚梯形衬砌渠道的断面形式。【方法】根据冻土力学、水力学、工程力学理论,分析弧脚梯形渠道砼衬砌冻胀破坏机理及破坏特征,指出对季节性冻土区弧脚梯形渠道最优断面的设计,要从结构抗冻胀和水力学两方面考虑,以砼衬砌体同时满足水力最佳及抗冻胀性能最优为原则,对弧脚梯形渠道断面的最优形式进行推导。【结果】根据工程实践中常用的取值范围,在综合考虑水力最佳断面及砼衬砌板抗冻胀性能最优的基础上,得到最优断面的几何参数,即水力最佳和抗冻胀性能最优的弧脚梯形最优断面为:渠底宽是设计水深的0.53倍,坡脚圆弧半径是设计水深的0.3倍,坡脚圆弧中心角即边坡板的倾角为51°。【结论】此断面形式不但能适应季节性冻土区渠道防渗抗冻胀工程的实践要求,而且便于机械化施工。