中草药在光合细菌开发中的应用

在培养基中添加一定浓度的木瓜,栝楼,女贞子,郁金等中草药的浸提液,可明显促进光合细菌的生长,其中以栝楼的效果最明显。某些中草药除本身有一定的抑菌作用外,不对光合细菌的抑菌作用有一定程度的提高。指出在水产养殖等实际应用中,添加某些中草药既能促进光合细菌的生长,又可增强其抑制其它细菌生长的能力。     

补偿曲线曲度与弦斜度相关性分析

①目的　统一平衡牙合 ５ 个因素的衡量标准平面和单位,探讨弦斜度与补偿曲线曲度的相关关系。②方法　应用 Ｘ 线立体摄影测量结合计算机技术,对哈尔滨市９９ 例青年的补偿曲线进行测量分析,并以圆心角代表补偿曲线曲度。③结果　弦斜度与圆心角呈高度正相关（ｒ＝ ０．９４７１, Ｐ＜ ０．０１）。方差分析示弦斜度性别差异有极显著性（ Ｆ＝ ７．７９１４, Ｐ＜ ０．０１）。④结论　用弦斜度代替补偿曲线曲度是可行的。     

用MTTp和F-V曲线形状对吸烟者肺通气功能的对比研究

为评价部分平均通过时间（ＭＴＴｐ）和Ｆ－Ｖ曲线形状对检查吸烟者小气道功能的临床意义,作者对１１６例被动和轻、重度主动吸烟者进行了常规肺通气功能、ＭＴＴｐ和Ｆ－Ｖ曲线形状的探讨。常规肺通气功能和Ｆ－Ｖ曲线形状用常规法测定。ＭＴＴｐ用“简易计算法”公式计算。结果显示凸型Ｆ－Ｖ曲线的分布随吸烟程度而上升。·Ｖ５０、·Ｖ２５下降及ＭＴＴ４５％～５５％、ＭＴＴ７０％～８０％延长在凸型与重度吸烟组一致。ＭＴＴ４５％～５５％与ＭＴＴ７０％～８０％延长的范围在两者都是预计值的１１０％～１２０％,表明小气道功能已有轻度障碍。因而凸型Ｆ－Ｖ曲线、ＭＴＴ４５％～５５％及ＭＴＴ７０％～８０％延长、·Ｖ５０、·Ｖ２５下降都是检查小气道功能的敏感指标。用“简易计算法”计算ＭＴＴｐ简便准确,宜于临床推广应用     

Abbreviated cyclosporine AUCs on Neoral – the search continues!

 Cyclosporine is a powerful immunosuppressant with a narrow therapeutic window and considerable inter- and intrapatient variability. The pre-dose trough concentration (C_min) is commonly used for therapeutic drug monitoring. With the new microemulsion (Neoral), intrapatient variability was reduced. However, the usefulness of Neoral C_min was questioned. Firstly, because of the improved and more-rapid absorption, accidental intake before blood sampling has a greater impact on C_min than with classic cyclosporine. Secondly, C_min may be low despite high drug exposure, due to rapid clearance in children. A full pharmacokinetic (PK) profile with determination of the area under the curve (AUC) is expensive and cumbersome, and therefore a search for an abbreviated AUC began. Here, we present a retrospective analysis of 84 PK profiles from 78 pediatric renal transplant recipients. By analysis of rejection episodes and toxicity, we estimated a target AUC above 5,000 ng×h/ml in the early post-transplant period and 3,900 ng×h/ml beyond 100 days. The abbreviated AUC using the 2- and 6-h concentrations (C2 and C6) and a simple estimate derived from the 3-h concentration (C3) were equally well correlated with the AUC. From our data, we recommend a target C3 at approximately 800 ng/ml early after transplantation and 450–550 ng/ml beyond 100 days. Received: 28 January 1998 / Revised: 10 June 1998 / Accepted: 15 June 1998     

Active vs. passive resistance, dose-response relationships, high dose chemotherapy, and resistance modulation: a hypothesis

Summary With chemotherapy, the in vitro and clinical dose-response curve is steep in some situations, but is relatively flat in others, possibly due to the mechanism by which tumors are resistant to chemotherapy. For tumors with resistance due to factors that actively decrease chemotherapy efficacy (e.g., p-glycoprotein, glutathione, etc.), one would predict that high dose chemotherapy and therapy with some resistance modulating agents would increase therapeutic efficacy. Such active resistance would most likely generally arise from gene amplification or over expression, and would be characterized by a shoulder on the log response vs. dose curve, with eventual saturation of the protective mechanism. On the other hand, one would expect that high dose chemotherapy and most resistance modulating agents would be of little value for rumors with resistance due to defective apoptosis or due to a deficiency in or decreased drug affinity for a drug target, drug activating enzyme, drug active uptake system, or essential cofactor. Such passive resistance would most likely generally arise from gene down regulation, deletion, or mutation, and would probably be characterized by a relatively flat log response vs. dose curve, or by a curve in which a steep initial section is followed by a plateau, as target, etc., is saturated. (If response were plotted vs. log dose, then compared to the curve for a sensitive cell line, the curve for active resistance would be analogous to the pharmacodynamic curve seen with competitive antagonism [i.e., a sigmoid curve shifted to the right], and the curve for most types of passive resistance would be analogous to the pharmacodynamic curve seen with noncompetitive antagonism [i.e., a sigmoid curve with reduced maximal efficacy]. As such, one might also refer to active vs. passive resistance as competitive vs. noncompetitive resistance, respectively.) Many tumor types probably possess a combination of active and passive mechanisms of resistance. New in vivo strategies could be helpful in defining dose-response relationships, mechanisms of resistance, and targets for resistance modulation. Such in vivo studies would be conducted initially in animals, but might also be tested clinically if animal studies demonstrated them to be feasible and useful. These in vivo studies would be conducted by randomizing 5–25 subjects to one of 10–20 dose levels over a potentially useful therapeutic range. Nonlinear regression analysis would then be used to define the characteristics of a curve generated by plotting against dose the log percent tumor remaining after the first course of therapy. While this might offer insight into the nature of resistance mechanisms present initially, plotting further tumor shrinkage vs. dose-intensity vs. course number for each later treatment course (or plotting dose-intensity vs. time to tumor progression) might provide information on how tumors become increasingly resistant to drugs following treatment.     

Epidemiological aids to clinical decision making in primary open angle glaucoma

We have described the epidemiological analysis of one aspect of the King's College Hospital computerised data base; namely initial intraocular pressure as an indicator of visual field loss. The methods involved the use of the four-fold table to determine sensitivity and specificity at different pressure levels. From these results (1) the changes in the pre and post test probability of field loss are calculated and (2) a sensitivity/specificity trade off curve or decision curve is constructed. In this way the optimal cut-off level or operating point for a population of specific type and composition can be determined. The factors concerned in decision making are always complex but such an approach allows a rational and quantifiable alternative to reliance on clinical impression and intuition. The results have significance in relation to decisions on the management of patients and on population screening programmes for glaucoma.     

Properties of hemoglobin and dextran-hemoglobin rightshifted by oxidized inositol tetrakisphosphate

Phytate was digested by wheat bran phytase to yield inositol tetrakisphosphate. Periodate-oxidized inositol tetrakisphosphate (oxyIP4) was coupled by means of reductive alkylation to hemoglobin and the covalent dextran-hemoglobin conjugate to yield the rightshifted (rs) compounds rsHb and rsDxHb, respectively. The variations of the oxygen dissociation curves of these molecules with pH and temperature were compared to those of hemoglobin. The variations with pH were found to be less pronounced for these rightshifted forms. An extensive decrease in the half-saturation oxygen tension was observed, however, with both rsHb and rsDxHb, as in the case of unmodified Hb. Modification of hemoglobin by oxyIP4 at the polyphosphate site was suggested by the lack of a further rightshifting effect of phytate on rsHb, and by the similarity between the difference spectrum of rs-methemoglobin and the difference spectrum induced by the addition of phytate.     

Distribution of lithium elimination rates in a selected population of psychiatric patients

Summary Chronic treatment with conventional lithium carbonate was interrupted in a selected group of 40 psychiatric patients of mixed sex and race. All patients had normal renal function. Serum samples were taken 12, 24, 36 and 48 h after the last dose and lithium was assayed by atomic absorption spectrophotometry. Decay rates calculated for the 12–24 h and 36–48 h periods yielded different values. This was ascribed to the presence of an incomplete redistribution phase during the earlier period. The distribution of elimination rates determined during the later period gave a more symmetrical spread and approximated a normal distribution. The mode, median, mean and standard deviation of the lithium elimination half-lives were 12.5, 14, 18.2 and 7.3 h and 22.5, 24.5, 29.8 and 10.1 h for the two periods, respectively. The results contrast sharply with another report of the distribution spread of elimination half-lives in a much larger sample. The current values have implications for dosage prediction, serum level monitoring and dosage formulation, especially sustained-release preparations. The evidence was against the possibility that some individuals retain lithium.     

胎儿生长的数学模型

根据孕 16～ 2 8周胎儿双顶径、头围、腹围及股骨长等的超声测量值拟合 Rossavik数学模型 [P=c(t) k+ s( t) ]建立胎儿个体生长曲线。结果显示 ,2 0例正常单胎的超声参数与 Rossavik模型的拟合效果好 ,孕 2 8～ 41周胎儿各项参数的模型预测值与实测值比较均无显著差异