Acute dose-effect relationships of caffeine and mental performance,EEG, cardiovascular and subjective parameters

The present study investigated the dose-effect relationship of caffeine on mental performance using a caffeine-sensitive rapid information processing task (RIP) in a pre/post cross-over design. Twenty female nonsmoking regular coffee drinkers received 0, 1.5, 3 and 6 mg/kg caffeine in a balanced order and the measurements were extended to cardiovascular, EEG and mood parameters. Surprisingly, the dose-effect curves for the different parameters were rather heterogeneous. Whereas increasing effects with increasing caffeine doses were observed for - and -EEG frequencies, anxiety, wakefulness, and some coffee ratings, negative dose-effect relationships were obtained for RIP processing rate and blood pressure. No apparent dose-effect relationships were seen for reaction time and motor activity. Thus, it was concluded that the dose-response relationships are rather shallow and heterogeneous and that the different parameters have different ranges in which they are sensitive to caffeine. The caffeine doses which might have beneficial behavioral effects are at the lower end of the tested dose range and comparable to those found in caffeine-containing beverages.     

Pharmacodynamics of Phenobarbital Anesthesia and Pentylenetetrazol-Induced Maximal Seizures in a Rat Model of Neoplastic Spinal Cord Compression

The purpose of this investigation was to determine whether paraplegia induced by neoplastic cord compression affects the pharmacodynamics of phenobarbital general anesthesia or of pentylenetet-razol (PTZ)-induced convulsions. Paraplegic rats harboring a thora-columbar epidural tumor, or an identical hindlimb tumor mass, received an i.v. infusion of phenobarbital until the onset of anesthesia. At that point, the phenobarbital concentrations in the CSF and serum were measured. Similarly, PTZ was infused until the onset of maximal seizures. It was found that changes related to systemic tumor growth and newly developed paraplegia due to neoplastic spinal cord compression did not attenuate the pharmacodynamics of phenobarbital. However, sustained paraplegia of 4 days duration reduced CNS sensitivity to the hypnotic action of the barbiturate as evidenced by the higher cerebrospinal fluid phenobarbital concentration required to induce anesthesia (170 ± 31 vs 125 ± 20 mg/L; P < 0.05). On the other hand, sustained paraplegia did not affect brain threshold concentration for PTZ-induced seizures.     

Structure-activity relationships and conformational features of antiherpetic pyrimidine and purine nucleoside analogues. A review

A rational approach to the design of antiherpetic nucleoside analogues is based in part on the broad specificity ol virus- coded thymidine kinases. Herpes virus thymidine kinase activates many 5-substituted 2-deoxyuridines, analogues ol thymidinc (e.g., idoxuridine, trifluridine, edoxudine, brivudine), 5-substituted arabinofuranosyluracil derivatives (e.g., 5-Et-Ara-U, BV-Ara-U, Cl-Ara-U), acyclonucleosides of guanine (e.g., aciclovir, ganciclovir, penciclovir), and purine nucleosides with the penlafuranosyl ring replaced by a cyclobutane ring (e.g., cyclobut-G, cyclobut-A). Activation involves selective, and frequently regiospecific, phosphorylation ol these analogues to the 5-monophosphales. These are further phosphorylated by cellular enzymes to the 5-triphosphates, which are usually competitive inhibitors of the viral-coded DNA polymerases. Some analogues are also incorporated into viral, and to a lesser extent cellular, DNA. A recent, unusual, exception is human cytomegalovirus, which does not code for a thymidine kinase, but for a protein with the sequence characteristics of protein kinase and which phosphorylates ganciclovir to its 5-monophosphate. The interaction of the analogues with cellular catabolic enzymes such as uridine and thymidine nucleoside phosphorylases is also discussed, as is the relationship between physicochemical properties (configuration, conformation, electronic and hydrophobic parameters) and antiviral activities, with particular reference to those drugs that are licensed, or under consideration, for clinical use.     

Law-like relationship between height and weight of school children

Ehrenberg’s Law-like relationship between height and weight [log was applied to a group of public school and Govt. school children in New Delhi. It was found that the model log was comparatively a good fit for public school children and the model log for Govt. school children. On fitting the model to the sample data it was found that the value of ‘a’ was 0.8, with some minor variation in the second decimal point and the value of ‘b’ was 0.39 & 0.36 respectively for public school boys and girls and 0.32 & 0.29 respectively for Govt. school boys & girls. These results corroborates with the findings of the earlier studies that the intercept constant ‘b’ in the Law-like relationship equation is influenced by the nutrition of children. This model is recommended because of its simplicity and practical usefulness using only already available information.     

Isovelocity investigation of the lengthening behaviour of the erector spinae muscles

The purpose of this study was to investigate the force-velocity (F/) relationship for the erector spinae muscles in submaximal activation movements, with particular attention to their response during lengthening movements and at lower shortening contraction velocities. Dynamic models that predict lower back muscle forces require reasonable representations of the modulating effect of instantaneous velocity. Ten males were observed performing trunk flexion and extension in the sagittal plane under constant load. Contraction velocities were measured as the first derivative from a devise sensitive to changes in spine curvature, and controlled by a visual feedback system while a constant load was applied through a chest harness. The erector spinae exhibited a yielding phenomenon which causes an abrupt drop in force during constant velocity stretching under constant, submaximal, stimulation. The findings were consistent with previous isovelocity muscle lengthening experiments. Yielding appeared dependent on the level of load/activation supporting the theory of a state-variableF/ relationship. The eccentric behaviour of the lower erectors (L3) seemed independent of velocity and length, while that of the upper erectors (T9) showed a dependence on length. At lower concentric velocities, concavity in torque-velocity curves was noted after a threshold velocity. The findings of this study strongly reinforce the notion that theF/ length relationship is not a continuous hyperbolic relationship during muscle shortening and that the commonly modelled force augmentation effect of lengthening is incorrect, at least for submaximal activation of the extensors of the lower back.     

Towards an ethics of immediacy A defense of a noncontractual foundation of the care giver—patient relationship

In this article, I argue that the relationship between patients and their health care providers need not be construed as a contract between moral strangers. Contrary to the (American) legal presumption that health care providers are not obligated to assist others in need unless the latter are already contracted patients of record, I submit that the presence of a suffering human being constitutes an immediate moral commandment to try to relieve such suffering. This thesis is developed in reference to the French philosopher Levinas and the Dutch theologian Schillebeeckx. An expanded version of the biblical parable of the Good Samaritan serves as test case.This revised version was published online in October 2005 with corrections to the Cover Date.     

二硫化碳作业女工早期胚胎损伤的剂量反应关系

目的 探讨女工二硫化碳（ＣＳ２）接触水平与胚胎早期发育障碍之间的剂量－反应关系。方法 前瞻观察生育女工妊娠所需的月 经周期数;收集每个月经周期胚胎植入期尿样,检测绒毛膜促性腺激素含量;监测女工作业地点ＣＳ２浓度。结果 ２５７名接触组经临床确诊妊娠的女工,各月经周期妊娠机率低于３６６名对照组女工,时间妊娠率随女工ＣＳ２接触水平（ＣＳ２接触浓度以ＣＳ２接触工龄）升高而降低：妊娠率＝０．７０３３－０．０     

云南拉祜族六个基因座的遗传多态性研究

目的：了解云南拉祜族６ 个短串联重复序列基因座遗传多态性分布。方法：应用复合扩增技术对ＣＳＦ１ＰＯ、ＴＰＯＸ、ＴＨ０１ 、Ｆ１３Ａ０１、ＦＥＳＦＰＳ和ｖＷＡ等６ 个ＳＴＲ基因座进行分析,采用高分辨率的聚丙烯酰胺凝胶电泳分离、银染法显影技术,对云南拉祜族上述６ 个ＳＴＲ基因座进行遗传多态性调查。结果：ＣＳＦ１ＰＯ基因座,观察到８ 个等位基因,２０ 个基因型;ＴＰＯＸ 基因座,观察到５ 个等位基因,１４ 个基因型;ＴＨ０１ 基因座,观察到６ 个等位基因,１７ 个基因型;Ｆ１３Ａ０１ 基因座,观察到６ 个等位基因,１３ 个基因型;ＦＥＳＦＰＳ基因座,观察到７ 个等位基因,１５ 个基因型;ｖＷＡ基因座,观察到７ 个等位基因,１７ 个基因型。结论：上述６ 个短串联重复序列基因座基因频率分布与Ｈａｒｄｙ Ｗｅｉｎｂｅｒｇ 平衡吻合良好。     

具强杀菌活性的兔Ⅱ型磷脂酶A2互补DNA克隆及其顺序确定的研究

目的:确定具强杀菌活性的兔Ⅱ型磷脂酶A2(PLA2)cDNA和蛋白质的一级结构,了解其杀菌功能与蛋白质一级结构的关系.方法:用PCR方法从兔骨髓cDNA库中克隆出Ⅱ型磷脂酶A2 cDNA并确定DNA顺序,推断出它的蛋白质一级结构;并与其它一些动物PLA2的结构进行比较.结果:成功获得了该磷脂酶A2的cDNA和蛋白质一级结构.它是目前上百种已知蛋白质一级结构的磷脂酶A2中碱性最强的蛋白,氨基酸组成中碱性氨基酸较丰富.其它具杀菌活性的哺乳动物Ⅱ型磷脂酶A2也都是碱性强的蛋白.结论:磷脂酶A2一级结构中富于碱性氨基酸是其具有杀菌功能的关键,而杀菌活性的强弱与其分子碱性强度呈正相关.     

解剖型钢板治疗肱骨远端粉碎性骨折

目的：探讨解剖Ｙ型钢板的临床应用价值。方法：报告３６例解剖Ｙ型钢板内固定肱骨远端粉碎性骨折,进行临床分析讨论,其中列,女８例,平均年龄３６．８岁。３６例中均行肘后标准切口尽骨鹰嘴截骨暴整个肱骨远端,Ｙ型钢板、螺钉内固定。结果：本组随访１～５年,其中优良率８６．２％。结论：解剖Ｙ型钢板治疗治疗肱骨远端粉碎骨折,效果确切,术后有利早期活动关节,减少并发症。