砷的致癌性研究进展

地方性砷中毒对人体造成的远期致癌效应,一直是世界各国广泛关注的问题。本文就砷的致癌机制研究中的一些热点问题,从遗传学机制和拟遗传学机制两个方面进行了综述,对砷影响免疫分子和细胞缝隙连接间通讯作用的有关研究进行了总结,并提出了今后研究工作的一些设想。     

Inhibition of BFU-E in vitro growth and of burst-promoting activity of T lymphocytes by serum of chronic uremic patients receiving hemodialysis

The effects of uremic serum on the in vitro growth of normal BFU-E and on the burst-promoting activity by normal T-lymphocytes were evaluated separately. The effect of hemodialysis on the removal of possible serum inhibitor(s) was also tested. Sera of 12 uremic patients were shown to provoke a 60% inhibition of the in vitro growth of normal BFU-E and almost complete abolition of burst-promoting activity by T lymphocytes. While hemodialysis significantly removed the inhibition of uremic sera on BFU-E growth, it was rather ineffective in removing the inhibitor(s) of T lymphocytes. The different effects of uremic serum on BFU-E and on T lymphocytes are discussed.     

Observations of the mechanism of action of the sulfonylureas under clinical conditions

Eight adult-onset diabetics were tested after 4 days stabilization on each of four regimens: no drug, oral chlorpropamide, glibenclamide, and tolbutamide during a fasting and a fed day. The overall mean plasma glucose levels were reduced by $\text{68}\text{mg}\text{100}\text{ml}$ on fasting, by 87 mg on the sulfonylureas and by 120 mg on fasting plus sulfonylureas. The overall mean fasting serum insulin (IRI) level of 12 μU per ml was increased by 5 μU on sulfonylureas, by 10μU on the fed day, and by 20 μU on the fed day with sulfonylureas. The sulfonylureas halved the mean rise in glucose level caused by food, while the mean rise in IRI levels was no greater on drugs than on no drugs. In all situations the potency of chlorpropamide and glibenclamide was similar and rather greater than that of tolbutamide, but there was no qualitative difference between the three drugs and the IRI levels were very similar on each. Plasma tolbutamide levels did not relate to IRI levels; tolbutamide was associated with a reduction in glucose levels 24 hr after the last dose. The increase in IRI levels on sulfonylureas was variable and irregular and did not correlate well with glucose levels. The pattern of change in plasma glucose and insulin and the lack of correspondence between glucose and tolbutamide levels appear to be explained best by an increased effectiveness of endogenous insulin rather than increased output even at this early stage (fifth to sixth day).     

Comparative study of the antihypertensive effect of verapamil and atenolol

A clinical trial in 24 patients with essential arterial hypertension (14 women and 10 men, mean age 47.5) was conducted on a double-blind basis using a placebo, 240-mg verapamil and 100-mg atenolol daily. The total duration of the trial was 12 weeks: a 2-week washout period on placebo, a 4-week period on one of the trial drugs, a second 2-week weaning period and a further 4-week treatment period on the other trial drug. Stabilization of the hypertension was obtained in 80% of the patients on verapamil and 71% of the patients on atenolol both in the supine and upright positions; there was no significant difference between the 2 drugs. A moderate decrease in heart rate was obtained. Sinus bradycardia was observed in 3 patients on verapamil and 4 patients on atenolol. No instances of atrioventricular block were observed on electrocardiogram. No adverse effects were reported with verapamil and in only 1 patient taking atenolol. Adequate stabilization of hypertension appears possible in most patients with both verapamil and atenolol.     

Impact of Medical Residency on Knowledge of Asthma

Objectives. To assess resident physician knowledge of pathophysiology, diagnosis, and management of asthma and to assess the impact of an interactive curriculum on that knowledge. Participants. A total of 720 resident and attending physicians at 15 internal medicine residency programs. Methods. An educational module and two multiple choice tests were developed using established methods of curriculum development and knowledge assessment, then disseminated online to 15 internal medicine residency programs. Baseline and post-intervention knowledge was analyzed according to year of training using Chi square to detect differences in group performance. Results. Baseline knowledge on asthma was poor. The average baseline score on all questions was 54.2%, and was worst on questions on diagnosis of asthma (47.5% correct) and questions on management of asthma (54.8% correct). Baseline knowledge was best on questions on the pathophysiology of asthma (71.5% correct). On specific concepts, only 41.9% correctly knew which pharmacotherapeutic agents were used as controller agents, and only 43.5% were able to correctly diagnose asthma severity. Knowledge on questions on diagnosis of asthma was no better in post-graduate year (PGY) 3 residents than in PGY1 residents (p = 0.054), but PGY3 residents performed better on questions about management of asthma than did PGY1 residents (p < 0.001). Knowledge improved for all concepts and at all levels of training after completion of an interactive module on asthma guidelines (p < 0.001). Conclusion. Resident physician knowledge of asthma guidelines is poor and can be improved by an interactive curriculum.     

Echocardiography diagnosis of a chronic course of myocarditis

It is reported on the results of echocardiographic investigations at rest and under ergometric exercise in 36 patients in whom in particular on account of an insufficiency of physical ability under everyday conditions which appeared after an infection the suspicion of a myocarditis arose. While the echocardiographic findings at rest were not indicative, the parameters SVI and mVCFn proved to be significant on exertion. Obviously, a decrease of these values is a particularly sensitive indicator for the detection of a latent damage of the myocardium. Echocardiographic investigations on exertion are of importance particularly in adolescents, since, on the one hand, above all in adolescents the danger of a physical overstrain is given, and, on the other hand, the prerequisites for the performance of echocardiographic are particularly favourable also under conditions of exertion. Since the in general usual and accessible investigation methods such as X-ray examination of the thorax, ECG at rest and on exertion, which practically fail in the diagnostics of myocarditis, completely new prospects open in the application of the echocardiography on exertion.     

Evaluation of immunochromatography method for rapid detection of Shigatoxin

The Shigatoxin detection kit based on the immunochromatography system is commercially available. To obtain the identification result rapidly, we devised the improved method (ICG-Imp) replaced to an original method (ICG). Modification provided that Shigatoxins extracted directly from the strains grown on TSI medium without centrifugation. ICG-Imp was compared with ICG, RPLA and PCR. Comparing with RPLA, the sensitivity, specificity, and concordance rate of Shigatoxin 1 showed 77.5, 100 and 90.5%, respectively on ICG, 93.8, 100 and 97.4%, respectively on ICG-Imp, and 100, 99.1 and 99.5%, respectively on PCR. On the other hand, the patterns of Shigatoxin 2 showed 95.3, 100 and 96.3%, respectively on ICG, 100, 100, and 100%, respectively on ICG-Imp, and 100, 100 and 100%, respectively on PCR. The time required from TSI medium to the final result are 24 h, 30-60 min, 48 h, and 6 h, respectively by ICG, ICG-Imp, RPLA, and PCR. It seems that the ICG-Imp is recommended for the identification by means of the accuracy and rapidness.     

珍珠提取物对氟在大鼠骨和牙沉积作用的影响

目的 探讨珍珠提取物对氟在大鼠骨、牙组织沉积作用的影响，为进一步研究其抗氟作用奠定基础。方法 两部分实验分别采用２种经饮水染毒给药方式：①每日饮水中同时加氟、给药（每升去离子水中含５０ｍｇ氟与６ｇ珍珠提取物）；②饮氟化水（每升去离子水中含氟１００ｍｇ）、给药（每升去离子水中含６ｇ珍珠提取物）隔日交替进行。用微波高压消解法和氟离子选择电极测氟。结果 实验１个月后，实验组动物股骨与门齿氟含量均远低于阳     

阿胶对体外培养大鼠成骨细胞增殖、分化功能的影响

目的 观察阿胶含药血清对体外培养大鼠成骨细胞增殖、分化功能的影响.方法 应用MTT法观察阿胶对体外培养成骨细胞增殖功能的影响,ELISA法观察阿胶对体外培养成骨细胞ALP含量的影响.结果 三个剂量组的阿胶含药血清对体外培养大鼠成骨细胞的增殖无促进作用,但对体外培养大鼠成骨细胞内ALP的合成有明显的促进作用.结论 阿胶对体外培养大鼠成骨细胞的增殖无促进作用,但能促进体外培养大鼠成骨细胞的分化功能.     

A selective phenomenology of the seismicity of Southern California

Predictions of earthquakes that are based on observations of precursory seismicity cannot depend on the average properties of the seismicity, such as the Gutenberg-Richter (G-R) distribution. Instead it must depend on the fluctuations in seismicity. We summarize the observational data of the fluctuations of seismicity in space, in time, and in a coupled space-time regime over the past 60 yr in Southern California, to provide a basis for determining whether these fluctuations are correlated with the times and locations of future strong earthquakes in an appropriate time- and space-scale. The simple extrapolation of the G-R distribution must lead to an overestimate of the risk due to large earthquakes. There may be two classes of earthquakes: the small earthquakes that satisfy the G-R law and the larger and large ones. Most observations of fluctuations of seismicity are of the rate of occurrence of smaller earthquakes. Large earthquakes are observed to be preceded by significant quiescence on the faults on which they occur and by an intensification of activity at distance. It is likely that the fluctuations are due to the nature of fractures on individual faults of the network of faults. There are significant inhomogeneities on these faults, which we assume will have an important influence on the nature of self-organization of seismicity. The principal source of the inhomogeneity on the large scale is the influence of geometry--i.e., of the nonplanarity of faults and the system of faults.     

A systematic review of the use of aromatherapy in treatment of behavioral problems in dementia

We aimed to fill the literature gap by identifying the clinical benefits of aromatherapy in older adults with dementia, and its efficacy in reducing behavioral and psychological symptoms of dementia (BPSD) based on available randomized controlled trials (RCT). A systematic review of 11 clinical trials shortlisted from electronic databases from 1995 to 2011 was carried out. The RCT showed that aromatherapy had positive effects on reduction of BPSD, improvement in cognitive functions, increasing quality of life, enhancing independence of activities of daily living and so on. However, adverse effects were noted in some studies. Limitations on methodology are discussed and suggestions on directions of further studies are made. It is recommended that aromatherapy shows the potential to be applied as a therapeutic and safe complementary and alternative therapy for the management of BPSD on more evidence collected from better designed RCT. Geriatr Gerontol Int 2012; 12: 372–382.     

Direct and indirect costs of osteoarthritis of the knee

BACKGROUND: Rheumatic diseases have an economic impact of 1-2.5% of GDP in industrialized countries and osteoarthritis is the most common joint disorder. Osteoarthritis of the knee is especially common and is a major cause of disability requiring extensive utilization of health care resources. OBJECTIVE: To estimate the burden of osteoarthritis of the knee in Italy, we studied retrospectively a cohort of 254 patients over a period of 12 months in 2000-2001. METHODS: Twenty-nine rheumatology institutes took part in the study. A bottom-up approach was used, analytically measuring pro capita consumption. We considered medical (hospitalization, diagnosis, and therapies) and non-medical costs (transport, temporary caregivers, and auxiliary devices) as direct costs. We calculated losses of productivity borne by patients and caregivers, and informal care provided by caregivers as indirect costs. RESULTS: Direct costs came to Euros 934 per patient per year: Euros 233 were spent on hospitalization, Euros 209 on diagnostic procedures (56% on visits and 44% on instrumental and laboratory tests), Euros 146 on therapy (58% on physiotherapy and 42% on drugs), and Euros 346 on non-medical costs (73% on salaries to temporary caregivers, 14% on transport, and 13% on auxiliary devices). It is interesting to point out that at least 37% of costs were charged directly to patients. Indirect costs were almost 30% higher and came to Euros 1236 per patient per year: 31% was due to loss of productivity of patients, 60% due to informal care provided by primary caregivers, and 9% by other caregivers. CONCLUSIONS: This study confirms that the direct and indirect costs attributable to osteoarthritis of the knee are substantial.     

Ultrasonic diagnosis of aneurysmal rupture of the sinus of Valsalva

Echocardiographic findings in 8 patients operated on for Valsalva's sinus aneurysm rupture are summed up: aneurysm and the site of its rupture shown on two-dimensional echocardiogram, abnormal diastolic blood flow through the aneurysm, evidenced by Doppler cardiography, and dilatation of cardiac chambers, dependent on the direction of blood discharge through the aorto-cardiac fistula.     

Vascular effects of estrogen and progestins and risk of coronary artery disease: importance of timing of estrogen treatment

The effects of estrogen and progestins on the vascular wall have drawn major medical attention, and significant controversy over various studies has been developed. Several experimental and observational studies have shown cardioprotective effects; however, prospective randomized trials showed an increase in cardiovascular events in postmenopausal women on estrogen/ medroxyprogesterone acetate treatment. The most significant parameter for cardiovascular benefit of estrogen seems to be the interval since the onset of menopause. In the early postmenopausal years, estrogen has beneficial effects on the vascular wall by inhibition of atherosclerosis progression, whereas in the late postmenopause, adverse effects like upregulation of the plaque inflammatory processes and plaque instability may develop. The effects of progestins on the cardiovascular system are not as clear and may differ according to the choice of progestins that is used. The aim of this review is to summarize the effects of estrogen and progestins on the vascular wall and their clinical implications.     

离子对日本血吸虫毛蚴趋向的影响

目的研究几种常见离子对日本血吸虫毛蚴趋向作用的影响。方法采用改良的Roberts比较法,以不同浓度的Fe3 、Ca2 、Fe2 、Na 、NH4 、Mg2 、Al3 溶液为实验组,等量去离子水作为对照组,检测这些离子对日本血吸虫毛蚴趋向作用的影响。结果Fe3 、Mg2 、Al3 对日本血吸虫毛蚴趋向的影响为显著吸引作用;Fe2 、Ca2 为排斥作用;NH4 和Na 对日本血吸虫毛蚴趋向的影响依离子浓度不同而有差异。结论不同的离子对日本血吸虫毛蚴趋向运动有不同的影响。     

Physiopathologic bases of the treatment of systemic scleroderma

Numerous drugs have been suggested for the treatment of systemic scleroderma. They may be studied and classified according to their site of action on the chain of events that leads from vascular abnormalities to sclerosis of the skin. Thus, proline analogues, colchicine, lathyrogenic agents, D-penicillamine, coagulation factor XIII and oestrogens are thought to act on collagens and their metabolism. Ketanserin has been suggested by the discovery of tryptophan abnormalities. Corticosteroids exert an inhibitory effect on fibroblasts. The use of calcium antagonists, angiotensin-converting enzyme inhibitors, prostacyclin and anti-platelets rests on the presence of vascular abnormalities. The purpose of treatments with immunosuppressive drugs or plasma exchanges is to act on possible lymphocytic and/or macropageal factors.     

Inhibition of some activities of thrombin by a collagen-derived octapeptide

The effect of a collagen-derived octapeptide on some properties of thrombin is presented. This peptide provoked a dose- and time-dependent prolongation of the thrombin-induced plasma and fibrinogen clotting time and inhibited the polymerization of fibrin generated from fibrinogen by thrombin. It did not affect the polymerization of fibrin monomers; it was also without effect on the coagulation of plasma or fibrinogen by reptilase. The prolongation of the fibrinogen clotting time depended on the duration of the incubation of thrombin and the octapeptide and not on the duration of the incubation of fibrinogen and the octapeptide. The inhibition was therefore ascribed to an interference with thrombin, rather than with fibrinogen. A preincubation of the octapeptide with thrombin resulted in an inhibition of the thrombin-induced platelet aggregation. The effect of the octapeptide on thrombin has been related to the presence of positively and negatively charged groups, because uncharged analogue sequences were without effect on these activities of thrombin.     

The impact of the use of statins on the prevalence of dementia and the progression of cognitive impairment

BACKGROUND: Previous evidence suggests that treatment with 3-hydroxy-3-methylglutaryl-coenzyme-A reductase inhibitors (statins) has a positive impact on dementia. We decided to investigate the association between the use of statins and the prevalence of dementia and statins' impact on the progression of cognitive impairment. METHODS: This is a case-control and a retrospective cohort study of a community-based ambulatory primary care geriatric practice. We included a convenience sample of all patients (N = 655, mean age 78.7 +/- 0.3 years, 85% Caucasian, 74% women) with hypercholesterolemia or dementia, or using statins. We compared those using statins with those who do not with respect to the clinical diagnosis of dementia and its subtypes and the progression of cognitive impairment. RESULTS: At the initial visit, 35% had dementia, and 17% were using statins. After covariate adjustments, patients on statins were less likely to have dementia (odds ratio [OR] for dementia based on composite definition = 0.23; 95% confidence interval [CI] [0.1-0.56], p =.001, OR Alzheimer's disease = 0.37; 95% CI [0.19-0.74], p =.005, OR vascular dementia = 0.25; 95% CI [0.08-0.85], p =.027). At follow-up, patients on statins showed an improvement on their Mini-Mental Status Examination score by 0.7 +/- 0.4 compared to a decline by 0.5 +/- 0.3 in controls, p =.025 (OR for no change or improvement on statins = 2.81; 95% CI [1.02-8.43], p =.045) and scored higher on the Clock Drawing Test (difference of 1.5 +/- 0.1, p =.036). CONCLUSIONS: The use of statins is associated with a lower prevalence of dementia and has a positive impact on the progression of cognitive impairment.