The relationship between the Stiles–Crawford effect of the first kind (SCE-I) and myopia

The Stiles-Crawford effect of the first kind (SCE-I) was measured on both emmetropic and myopic subjects at six different retinal locations. The results revealed a number of significant discrepancies in receptor alignment between the groups of different refractive errors. In myopic subjects, the receptors in the nasal retina (i.e. between the fovea and the optic nerve head) were found to be aligned nasally towards the optic nerve head, whereas the receptors in the temporal retina were aligned towards the centre of the exit pupil. In emmetropic subjects, the receptors across the retina were finely tuned towards the centre of the exit pupil. The magnitude of the receptor displacement in myopic subjects was found to be directly associated with the length of the eyeball.     

心脏营养素-1治疗失神经骨骼肌萎缩过程中对正常肌肉组织的影响

目的 探讨应用心脏营养素-1(cardiotrophin-1,CT-1)治疗失神经骨骼肌萎缩的有效剂量和安全剂量,观察不同剂量的CT-1对正常骨骼肌、心肌和血管平滑肌的副作用.方法 取Swiss小鼠80只,随机分成8组,每组分别于胫神经切断术后连续腹腔注射重组小鼠CT-1(rmCT-1)40、60、80、100、120、140、160μg·kg-1·d-1,剩余1组腹腔注射等体积CT-1溶媒,28d后称量失神经侧腓肠肌、正常侧腓肠肌和心脏的湿重;测量胸主动脉平滑肌厚度;检测正常腓肠肌中α-actin和MHC Ⅱa以及心肌中β-MHC的表达、胸主动脉血管平滑肌细胞中α-actin的含量.结果 采用腹腔注射给药,当CT-1用量达到60μg·kg-1·d-1时,开始对失神经骨骼肌产生营养作用,并呈剂量依赖性增强,当给药剂量超过100 μg·kg-1·d-1后,出现对正常骨骼肌、心肌和血管平滑肌的影响.给药剂量达到120μg·kg-1·d-1时,开始促进心肌β-MHCmRNA的表达,增加正常心脏的湿重.当给药剂量达到140μg·kg-1·d-1时,开始促进正常骨骼肌α-actin和MHC Ⅱ amRNA的表达,以及骨骼肌湿重的增加,同时提高了主动脉血管平滑肌α-actin的含量,增加了血管平滑肌的厚度.结论 腹腔注射CT-1防治失神经骨骼肌萎缩的有效剂量为60 μg·kg-1·d-1,最高安全剂量为100 μg·kg-1·d-1.当给药剂量达到120 μg·kg-1·d-1时,开始出现心肌肥厚,当给药剂量达到140 μg·kg-1·d-1时,可导致正常骨骼肌的肥大和血管平滑肌的增厚.     

尼尔雌醇和左炔诺孕酮对人成骨肉瘤 MG-63细胞株雌激素受体亚型的作用

目的：观察不同浓度的尼尔雌醇(NYL)和左炔诺孕酮(LNG)对人成骨肉瘤MG-63细胞株ERα和ERβ表达的作用，探讨旁分泌效应对ERα和ERβ基因表达的影响。方法：人成骨肉瘤MG-63细胞株分为（1）空白对照组：用含1% BSA无血清MEM培养液培养48 h；（2）阳性对照组：培养液中加入10-8 mol/L的17β-estradiol (E2) 培养48 h；（3）药物处理组：培养液中分别加入10-10，10-8，10-6 mol/L的NYL或LNG培养48 h；（4）药物处理+换液组：培养液中分别加入10-10 mol/L的NYL或10-8 mol/L LNG培养48 h，每12 h更换新的含有相应药物的培养液。用半定量RT-PCR检测各组细胞ERα和ERβmRNA的表达。结果：NYL及LNG均能诱导ERα和ERβ亚型mRNA表达上调，诱导ERαmRNA表达的最强作用浓度均为10-6 mol/L。NYL，LNG对ERβ mRNA表达最强作用浓度分别为10-10，10-8 mol/L。每12 h更换干预培养液对ERα表达无影响，但可抑制ERβ的表达。结论：NYL和LNG均可诱导MG-63细胞株ERα和ERβ mRNA表达上调，且2种亚型的表达存在相互制约关系；在NYL和LNG诱导ER亚型表达上调过程中ERβ的表达可能受到旁分泌作用的影响。     

Physiological pharmacokinetics of solutes in the isolated perfused rat hindlimb: Characterization of the physiology with changing perfusate flow,protein content,and temperature using statistical moment analysis

Distribution of Evans Blue (EB), sucrose, and water into the isolated perfused rat hindlimb was studied under various conditions using the multiple indicator dilution (MID) technique. Statistical moment analyses of the outflow profiles for the EB, sucrose, and water were used to define the vascular, extravascular, and total water spaces, respectively. The varied perfusion conditions included albumin content (2, 4.7, and 7%), temperature (25, 37, and 42 C), perfusate flow rate (2, 4, 8, and 12 ml/min) and the presence/absence of red blood cells. The range of studies undertaken were chosen to represent the variety of conditions used in the preparation of both isolated animal and human limbs, the latter being particularly important in cytotoxic therapy for recurrent malignant melanoma. The distribution volumes of EB, sucrose, and water were dependent on the flow rate and the albumin content of perfusate. The normalized variances (CV ² ) of the markers were of the following order: sucrose (2.18) > water (1.58) > EB (0.68), indicating that some disequilibrium occurs during the capillary exchange of water and sucrose. It is suggested that a Krebs-Henseleit buffer containing 2% BSA is a suitable perfusate for most studies of the isolated rat hindlimb perfusion. The effect of albumin concentration manifests itself only at higher flows.We acknowledge the support of the National Heart Foundation (Queensland) and the Mayne Bequest Foundation. This study was conducted while the investigator (Z.Y. Wu) was in receipt of a WHO Research Training Grant. Professor M. S. Roberts also acknowledges the support of the Queensland and Northern New South Wales Lions Kidney & Medical Research Foundation.     

Validity of a hinged constant force probe and a similar, immobilised probe in untreated periodontal disease

The validity of a hinged constant force probe (0.25 N) was compared with that of a similar but immobilised instrument, using the same interchangeable tip for both (0.64 mm diameter; 2 mm divisions). 60 sites were measured on teeth which were extracted subsequently, in patients with untreated periodontal disease, and the connective tissue attachment level was used as validity criterion. The clinical measurements of both probes correlated well with each other, but they differed significantly from the post-extraction connective tissue attachment level measurements, indicating a point 1.2 mm coronally to this, on average. A companion investigation of intra-operator probing depth reproducibility with the 2 probes, was undertaken in 14 patients, at 2 visits separated by 1 week in each case. All patients had untreated periodontal disease. A difference between probes was found at the first visit, but not at the second; the immobilised probe showed a difference between visits, reducing mean probing depth slightly at the second; when the immobilised probe was used first, there was a difference between probes. Further analysis of the results indicated that there was greatest agreement between probes when the constant force probe had been used before the immobilised probe at the second visit. The results suggested that these probes indicated a point above the connective tissue attachment level, related to pocket morphology, and that there was a moderate learning effect due to operator use of the constant force probe, which modified use of the immobilised probe.     

Chronotropic and inotropic effects of histamine in developing chick heart: differential mechanisms before and after hatching

Chronotropic and inotropic effects of histamine were examined in isolated atrial and ventricular preparations from embryonic and hatched chicken hearts. Histamine produced positive chronotropic and inotropic responses both in embryonic and hatched hearts. The responses to histamine in middle embryonic myocardia, which were observed in the micromolar range, were antagonized by H₂ antagonists but not by H₁, H₃ antagonists and propranolol. Isobutylmethylxantine, an inhibitor of phosphodiesterase, produced a leftward shift of the concentration-response curve for the chronotropic effect of histamine in the embryo. The responses to histamine in myocardia from hatched chicks, which were observed in the milimolar range, appeared concurrently with the responses to tyramine during development and were antagonized by beta adrenoceptor antagonists but not by any of the histamine antagonists. The positive inotropic response to histamine in hatched ventricular preparations were greatly attenuated by reserpine pretreatment or in the presence of desipramine. Thus, we demonstrated that exogenously applied histamine produces positive chronotropic and inotropic responses in developing chicken hearts and that the mechanisms are different between embryonic and hatched chicks: direct action on H₂ receptors in the embryonic heart and release of norepinephrine from sympathetic nerve terminals in hatched hearts.     

龙眼参提取物对耐药口腔上皮样癌细胞株KB／MIT及耐药乳腺癌细胞株MCF-7／ADR的逆转作用

目的：研究龙眼参提取物XCKB／MIT细胞及MCF-7／ADR细胞株的耐药逆转作用。方法：设计4个不同浓度的龙眼参提取物组，采用MTT方法．测定体外培养的阿霉素敏感株MCF-7及其耐药株MCF-7／ADR以及米托蒽醌敏感株KB及其耐药株KB／MIT的IC50。结果：MCF-7／ADR耐药株及KB／MIT耐药株在龙眼参提取物与阿霉素或米托蒽醌的联合用药中其IC50值分别接近于单独用约于敏感株MCF-7和KB的水平．而与单独用药于耐药株其IC50有显著性差异。结论：龙眼参提取物可以逆转MCF7／ADR和KB／MIT的耐药性。     

H^＋—ISFET的性能特点及应用研究

本文报道由我们研制的氢离子半导体传感器的性能特点，并与普通离子选择电极（玻璃电极）比较。Ｈ＾＋－ＩＳＦＥＴ具有体积小、取样少、快速、稳定、全固体化、不用预先活化等优点，对氢离子的敏感性也优于普通玻璃电极。本文还成功地将Ｈ＾＋－ＩＳＦＥＴ应用于有复杂成分并存的尿、血及其他生物材料的ｐＨ值测试，并改进胆碱酯酶活力测定方法，将Ｈ＾＋－ＩＳＦＥＴ应用于有机磷中毒后胆碱酯酶活力的快速定量测定。     

Modeling the pharmacokinetics and pharmacodynamics of dexamethasone in depressed patients

Summary Changes in time course effected by cortisol suppression and the relationship of these changes to the plasma dexamethasone concentration of suppressor and non-suppressor patients are described in this report on a combined pharmacokinetic-pharmacodynamic model.Thirteen depressed patients (8 suppressors and 5 non-suppressors) received an intravenous dose (1.5 mg) of dexamethasone. The drug-induced effect changes are found to lag behind, in time, the plasma drug level changes. To accurately relate the temporal relationship of effect changes to plasma dexamethasone levels, a pharmacodynamic model (sigmoid-Emax) was combined with a pharmacokinetic model that incorporated an effect compartment. The magnitude of the time-lag was quantified by the half-time of equilibration between concentrations in the hypothetical effect compartment and the plasma dexamethasone levels (t_&frac;k_eo).The t_&frac;k_eo of the nonsuppressing group was about 50 of that of the suppressing group, indicating that for a given plasma level the onset and termination of effect for the nonsuppressing group is about two times more rapid than for the suppressing group. Moreover, the model can estimate the effect-site concentration that causes one-half of the maximal predicted effect (EC₅₀), a measure of an individual's sensitivity to dexamethasone. The receptor sensitivity (as determined from the EC₅₀ ratio) of the suppressing group was about twice that of the nonsuppressing group.