合欢皮中三萜皂甙元的研究

合欢皮中三萜皂甙元的研究陈四平张如意（北京医科大学植化教研室，北京１０００８３）中药合欢皮（Ａｌｂｉｚｚｉａｅｃｏｒｔｅｘ）为合欢（ＡｌｂｉｚｚｉａｅｊｕｌｉｂｒｉｓｉｎＤｕｒａｚｚ）树皮。具解郁安神，活血消肿功能。用于心神不安，忧郁失眠，肺痈疮肿...     

AUTACOID INTERACTIONS IN THE REGULATION OF BLOOD FLOW IN THE HUMAN PLACENTA

1. Interactions between autacoids may play important roles in the regulation of blood flow in the foetal placenta. In order to investigate this aspect of placental haemodynamics, human normal-term placentae were perfused in vitro and the responses of the foetal vessels to various combinations of vasoactive agents were determined. 2. Vasoconstriction responses to 5-hydroxytryptamine (5-HT) were potentiated in the presence of endothelin-1 (ET-1), the thromboxane A₂-mimetic U46619 and a nitric oxide synthase inhibitor, N-nitro-l -arginine (NOLA), but not in the presence of angiotensin II. 3. N-Nitro-l -arginine caused vasoconstriction of the perfused placenta and indomethacin attenuated this effect and blocked the potentiation of the 5-HT response by NOLA. 4. Indomethacin did not affect ET-1-induced pressure increases and infusion of U46619 had no effect on release of ET-Iike immunoreactivity into the foetal placental circulation. 5. The present study provides evidence of interactions between several autacoids in human perfused placentae in vitro. These interactions may play important roles in foetal placental haemodynamics in normal or pathological situations.     

Induction of an anomalous blue-green wavelength discrimination by reduced viewing time

Wavelength discrimination was studied on three colour-normal human observers for open viewing and for reduced time viewing. All three observers show a loss of blue-green wavelength discrimination when viewing time is reduced to 3.75 msec. This loss is shown to be an effect of viewing time alone and not of reduced retinal illuminance. The results confirm those reported by Foster, Scase and Taylor¹ although the target size and methodology are different.     

Attention deficit hyperactivity disorder: Perceptions, practice and politics

Abstract: Some of the issues related to the doubts and complexities involved in the diagnosis and treatment of attention deficit hyperactivity disorder (ADHD) are reviewed. While some writers claim that it is clear that all children presenting with ADHD should be treated by pharmacological means, there are associated risks and politics. However, in the absence of well established and research-supported alternative understandings of the aetiology and treatment of the disorder, many practitioners feel unable to offer a useful service. Resulting frustrations have led some parents to form their own support networks, which make strong demands for increased services. More creative and innovative therapeutic interventions focusing on the broader impact of ADHD must be developed to deal with this disorder.     

Cerebral oxygenation during cardiopulmonary bypass

Cerebral fractional oxygen extraction (FOE) was monitored in 30 children, using near infrared spectroscopy during cardiopulmonary bypass, to investigate the effect of hypothermia and circulatory arrest. One group of children (n = 15) underwent profound hypothermia with total circulatory arrest (n = 8) or continuous flow (n = 7). Another group (n = 15), of whom only one had circulatory arrest, underwent mild (n = 6) or moderate (n = 9) hypothermia. The mean FOE (SD) before bypass was 0.35 (0.12) and this correlated negatively with the preoperative arterial oxygen content (r = -0.58). Between the stage of cooling on bypass and cold bypass there was a reduction in FOE in all groups. Between cold bypass and rewarming there was an increase in FOE only in the groups with continuous flow. In the circulatory arrest group, the FOE remained low during rewarming and was significantly lower than that of the continuous flow group. No patients died and none had neurological abnormalities postoperatively. Apparent changes in oxidised cytochrome oxidase concentration were also monitored using near infrared spectroscopy. There was a fall in cytochrome aa3 on starting cardiopulmonary bypass, but there were no significant differences in the changes in cytochrome aa3 between any stage in any of the patient groups. Using this non-invasive technique, cooling was shown to reduce cerebral FOE. During rewarming on bypass there was an increase in cerebral FOE only in patients who had had continuous flow bypass. In contrast, the cerebral FOE in those with circulatory arrest remained constant after arrest and during the duration of the study. This may have implications for the timing of hypoxic brain injury.     

MULTIDRUG RESISTANT TUBERCULOSIS – BIOMECHANISM,EPIDEMIOLOGY AND MANAGEMENT STRATEGIES

Muitidrug resistant tuberculosis has shown an alarming increase and this assumes added importance in view of the increasing number of HIV infected patients. This article reviews the biomechanism of resistance and discusses the present stategies that are available and recommended to tackle the rising incidence of tuberculosis due to resistant mycobacteria.KEYWORDS: Antitubereular drugs, Drug resistance, Mycobacterium tuberculosis     

Vitamin A intake and xerophthalmia among Indian children

OBJECTIVE: To estimate prevalence of xerophthalmia and to assess dietary intake of vitamin A in Indian children aged under 6 y. DESIGN: Cross sectional study. STUDY SETTING: Urban slums under Urban Health Centre affiliated to Department of Preventive and Social Medicine, Government Medical College, Nagpur, India. PARTICIPANTS: The study included 1094 all children under 6 y of age, from two randomly selected urban slums. METHODS: Xerophthalmia was diagnosed on the basis of ocular signs and symptoms (WHO recommendations). Dietary intake of vitamin A was assessed by using one year recall method recommended by International Vitamin A Consultative Group. RESULTS: Prevalence of xerophthalmia was estimated to be 8.7%. Nine hundred and ninety-five (90.9%) study subjects were identified as inhabitants consuming dietary vitamin A at below recommended levels. (UPF score < 210). Five hundred and ninety-three (54.2%) study subjects were consuming dietary vitamin A at approximately less than 200 RE/d (UPF score < 120) while 402 (36.2%) were consuming approximately 200-300 RE/d (UPF score 120-210). The prevalence of xerophthalmia was found to be decreasing as the score of usual pattern of food consumption (UPF) increased. CONCLUSIONS: Children with a dietary intake represented by a UPF score of less than 120 were at high risk of developing xerophthalmia, whereas, those consuming vitamin A equal to a UPF score greater than 120 were at comparatively less risk despite being below the recommended levels.