激光上皮下角膜磨镶术后角膜上皮瓣临床观察

目的 观察及探讨准分子激光上皮下角膜磨镶术(Laser subepithel ialkeratomileusis，LASEK)后，角膜上皮瓣的成活率及其影响因素。方法 对行LASEK治疗的42例(80眼)于术后1、2、3天，1、2、3、4周在裂隙灯显微镜下进行角膜上皮瓣的观察。结果 34例(68眼)，角膜上皮瓣成活，成活占85％(68／80)；未成活8例(12眼)，未成活占15％(12／80)。结论 LASEK术后角膜上皮瓣成活率的高低，决定着LASEK的临床疗效，影响其成活的因素是多方面的。其中角膜上皮瓣边缘不整齐、破裂、对位不良、操作时间过长可能是其主要原因。     

计算法测定肾小球滤过率的临床应用价值

目的 :探讨采用 WCP公式计算方法测定肾小球滤过率 (GFR)的临床应用价值。方法 :采用 99m Tc DTPA清除率测定 6 6例不同疾病住院患者 GFR(Tc GFR) ,并测血清肌酐 (SCr)及尿素氮 (BU N) ,同时以 WCP公式、Robert公式计算 GFR(WCP GFR,Robert GFR) ,以 Cockcroft/ Gault公式计算内生肌酐清除率 (CG CCr) ,所得数据进行对比研究及相关性分析。结果 :除肾功能正常者 CG CCr与 BU N无显著相关外 ,肾功能不全及肾功能正常者的 WCP GFR、Robert GFR、CG CCr均分别与 Tc GFR呈显著正相关(P均 <0 .0 1) ,与 BU N、SCr呈显著负相关 (P<0 .0 1或 P<0 .0 5 ) ;与 Robert GFR、CG CCr比较 ,WCPGFR始终与 Tc GFR最接近 (P均 >0 .0 5 ) ;WCP GFR、Robert GFR、CG CCr与 Tc GFR的平均差绝对值逐渐增大 ,三者间差异显著 (P均 <0 .0 5 )。结论 :WCP GFR、Robert GFR、CG CCr均能在一定程度上准确反映 GFR,而以 WCP GFR更准确 ,且简便、快速、安全而廉价 ,可代替 Tc GFR应用于临床     

Effects of low-dose transdermal scopolamine on autonomic cardiovascular control in healthy young subjects

We studied how posture influences the effects of transdermal scopolamine on autonomic cardiovascular regulation in a randomized, double-blind, placebo-controlled crossover study of 10 healthy young volunteers. We recorded the electrocardiogram and auscultatory sphygmomanometric and continuous non-invasive finger arterial pressure (Finapres device) to obtain signals for the beat-by-beat R–R interval and systolic, mean and diastolic pressures. R–R interval and arterial pressure variabilities were characterized by power spectral analysis. Scopolamine increased the mean R–R intervals and reduced arterial pressure in both the supine and the standing positions, but did not affect blood pressure variability. Scopolamine increased the total variability of R–R interval and its mid- (0·07–0·15 Hz) and high- (0·15–0·40 Hz) frequency band power in the standing position during controlled breathing at 0·25 Hz. In the supine position, scopolamine did not affect R–R interval variability. In the deep breathing test, scopolamine increased the maximal expiratory–inspiratory R–R interval ratio. This study showed that low-dose scopolamine increases vagal cardiac inhibition in both supine and standing positions in healthy volunteers. However, scopolamine increases heart rate variability only in the standing position during partial vagal withdrawal. The study also demonstrates that transdermal scopolamine decreases blood pressure in healthy young subjects.     

中华按蚊感染马来丝虫后蚊存活率的变化

实验室驯化的中华按蚊，通过人胎盘膜，吸取含马来丝虫微丝蚴的新鲜兔血而获感染。在温度为２８℃，相对湿度为７５－８５％的实验条件下，观察了中华按蚊感染马来丝虫主存活率的变化。结果表明，感染微丝蚴密度最高组蚊的存活率比其它各组明显下降。     

化学染发剂和冷烫精的毒性及对人体健康影响的调查研究

本文通过化学染发剂和冷烫精对大白鼠骨髓多染红细胞，毛囊细胞的微核实验及人群健康影响调查，结果表明化学染发剂，冷烫清具有较强致突变作用，两者同时使用致突变明显增强，并提出研制高效无毒染发剂和加强防护的重要性。     

直线加速器十年故障分析总结

目的分析和总直线加速器十多年来的故障。方法根据十多年来的故障维修记录，统计和分析直线加速器各阶故障率及故障特点。结果直线加速器使用早期由于机器不稳定故障率比较高，使用中期及其比较稳定，故障率比较低，使用后期由于零部件老化，故障率比较高。     

Renal regulation of salt balance: a primer for non-purists

The greater than 40-fold range of voluntary salt intake in humans requires corresponding adjustments in renal excretion to maintain balance. Although many mechanisms have been implicated in the regulation of salt output by the kidney, surprisingly little consideration has been given to their quantitative significance and possible interaction. This survey summarizes the effects of changes in glomerular filtration rate, proximal peritubular physical factors, and plasma concentrations of aldosterone and atrial natriuretic factor (ANF), singly and in combination, on the level of salt excretion. Contrary to expectation, even large increases in filtration or decreases in proximal reabsorption have only minor natriuretic effects, due to constancy of fractional reabsorption in downstream nephron segments. Lack of aldosterone release increases salt excretion as much or more than the upstream mechanisms, whereas ANF-induced inhibition of reabsorption in the medullary collccting duct has the largest effect. It may be concluded, therefore, that the potency of these natriuretic factors increases with distance along the nephron, even though each is operating on a progressively small tubular load. However, none of the mechanisms, in isolation, is sufficient to explain salt balance over the range of voluntary intake. Combination of factors demonstrates synergism rather than simple additivity, resulting in more than enough reserve capacity for salt excretion.     

Effect of Central Muscarine Receptor Blockade with DKJ-21 on the Blood Pressure and Heart Rate in Stress-Induced Hypertensive Rats

Da-Nian Zhu, Long-Mei Xue, Peng Li. Effect of central muscarine receptor blockade. with DKJ-21 on the blood pressure and heart rote in stress-induced hypertensive rats.

The experiments were performed on Wistar or Sprague-Dawley rats of both sexes divided at random into stress and control groups. The rats in the stress groups were put into cages and subjected to electric foot-shocks and noises for 9-15 days, which caused an increase in blood pressure (BP) and heart rate (HR). In hypertensive rats DKJ-21 (4mg/lml) was injected intravenously (i.v.), and 0.5-1.0h after administration the BP and HR dropped from the high level to normotensive level. In normotensive rats, however, administration of DKJ-21 had no effect on BP or HR. In separate groups of normotensive rats, pretreatment of DKJ-21 (4 mg/l ml, i.v.) blocked the pressor and tachycardiac effect induced by microinjection of physostigmine (0.4μg/0.1 /μl/site), corticosterone (40μg/0.1μl/site) or aldosterone (40 μg/0.1 μl/site) into the rostral ventrolateral medulla (rVLM). Furthermore, DKJ-21 also attenuated the enhancement of the pressor response to stimulation of the defense area in the midbrain, which was induced by microinjection of drugs (mentioned above) into the rVLM. These results indicate that i.v. DKJ-21 can selectively block the muscarinic receptors in the rVLM in stress-induced hypertensive rats, which suggests that abnormal enhancement of cholinergic mechanism in the rVLM may be related to hypertensive effects of corticoids in this area.     

Menstrual-Linked Asthma

This study was conducted to determine the occurrence of menstrual-linked asthma (MLA) in India in 100 consecutive female asthmatics in the reproductive age group. The patients were required to respond to a questionnaire concerning the relationship between their asthma and the menstrual cycle. Twenty-three patients had subjective perception of deterioration in symptoms of asthma in relation to the menstrual cycle. Ten patients from both groups were also required to maintain a daily peak expiratory flow rate (PEFR) diary for 2 consecutive menstrual cycles. The mean total duration of illness in patients with MLA was significantly longer than in patients without cyclic exacerbation. Cough and breathlessness were also significantly more severe as was the disease. This was evidenced by the more frequent emergency room visits and hospitalizations in these patients. Menstrual-linked worsening of asthma was most common in the premenstrual week (17 patients). In 8 of these 17 patients, this phenomenon continued to occur during the menstrual week also. Interestingly, 1 patient complained of deterioration of asthma 2 days after menstruation was over. Such an observation is yet to be recorded. Fourteen patients reported an increase in symptoms with almost every cycle while 3 had worsening related to specific season only. Sixteen patients often required extra medication during the premenstrual and/or menstrual weeks. A significant association was also observed between severity of premenstrual syndrome and MLA. The mean PEFR values over 2 cycles revealed a significant fall in the morning as well as evening values in the premenstrual and menstrual weeks as compared to the midcycle week in patients with MLA. This fall was maximal in the premenstrual week. Such a fall was not observed in asthmatics without menstrual exacerbation of symptoms. MLA was detected in about a fourth of the female asthmatics in India and it appears to represent a more severe form of the disease. This study also documented that MLA was associated with an increase in airway resistance and was not simply due to an increased perception of symptoms during the premenstrual or menstrual weeks.     

Decreased R-R variation: A criterium for overdosage of tricyclic psychotropic drugs

Objective Since intoxication with tricyclic antidepressants is common, a supplementary screening method for differentiation between therapeutic and supratherapeutic ranges would be a valuable diagnositc tool, particularly in delirious and unconscious patientsSetting 109 patients treated with amitriptyline, 8 patients treated with doxepin, 10 patients treated with clozapine, and 72 normal control subjects matched for age and sex were tested for heart rate variability while resting.Results Considering time and frequency derived measures, which are rather independent of heart rate, the patients showed significantly decreased heart rate variability parameters (p<0.0001), as compared with the normal subjects. Of the patients presenting delirious symptoms 6 showed coefficients of variation more than 4 standard deviations below the mean control value.Conclusions As heart rate variability can be easily calculated, this measurement is suggested as a useful tool to quickly exclude or support the diagnosis of chronic intoxication with tricyclic antidepressants or clozapine.