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1.
刺梨酸的分离与结构研究 总被引:5,自引:0,他引:5
从刺梨中分离出一种新的五环三萜酸,命名为刺梨酸。通过光谱分析和衍生物的制备,确定其化学结构为2β,3α,7β,19α-四羟基乌苏-12-烯-28-羧酸。 相似文献
2.
刺梨汁对慢性氟中毒的影响及机理研究 总被引:1,自引:0,他引:1
用高氟饲料喂养大鼠6个月,复制出慢性氟中毒模型,再自由饮用刺梨汁3个月,探讨刺梨汁对慢性氟中毒的影响及机理。结果表明:刺梨汁可明显改善氟中毒的一般状况,对已形成的氟斑牙影响不大,但可促进尿氟排泄,降低血清和骨氟含量及尿羟脯氦酸含量,提高血清中维生素C、维生素E和血清、肝、肾GSH含量,增强血、肝、肾GSH-Px和SOD活性,降低血清、肝和肾LPO含量,降低尿γ-GT和血清GPT活性及肝TG含量,提示:刺梨汁具有明显桔抗慢性氟中毒作用,其机理可能是通过促进尿氟排泄和抗氧化作用。 相似文献
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A comprehensive survey was carried out to asses the Vitamin A status of pre-school (0–6 yrs.) and school age (6–12 yrs.) children
of socio-economically backward families from slums of Bombay and its suburbs. The Vitamin A, protein, calories and iron from
the rice and dal based diet was found to be below recommended dietary allowances (RDA). Among the 1956 children surveyed 20%
of the children showed low (<20 μg/dl) serum vitamin A levels. 4.8% of the children were suffering from one or the other signs
of Vitamin A deficiency. Rose Bengal stain test (RBST) and conjuctival impression cytology (CIC) indicted the signs of mild
conjuctival xerosis and of early epithelial changes which were correlated with serum vitamin A levels. Serum iron, PCV, Hb
and RBC levels were below normal. The anthropometric measurements of these children were below 50th percentile of Indian Council
of Medical Research (ICMR) standards. Due to lack of proper nutrition, the overall growth of children is either retarded or
not upto the standard levels as was noted in majority of the children. 相似文献
5.
Objective
Retrograde intubation of canaliculi during dacryocystorhinostomy can restore canalicular patency in cases otherwise managed with bypass tubes. The surgical technique and success for this procedure are discussed.Design
A retrospective, noncomparative case series with clinic or telephone interview for long-term follow-up of patients’ symptoms.Participants
One hundred two patients who had undergone this particular lacrimal drainage surgery at Moorfields Eye Hospital between 1992 and 1997.Intervention
All patients underwent a dacryocystorhinostomy and retrograde canaliculostomy while under general anesthetic.Main outcome measures
Relief or reduction of epiphora and discharge.Results
One hundred twenty-three lacrimal systems of 102 patients were included. There were 53 females and 49 males, with ages at surgery ranging from 6 to 83 years (mean, 49 years). The etiology was idiopathic (30%), herpetic canaliculitis (24%), punctal agenesis (18%), and trauma (11%); less-common causes included dacryocystitis, Stevens-Johnson syndrome, eczema, and prior radiation therapy. Both upper and lower canalicular systems were involved in the majority (73%) of patients, and in 13 (11%) systems a dacryocystorhinostomy had previously been performed. The silicone tube was placed for a mean of 2 months (range, 1 week–9 months), and the mean postoperative follow-up was 8 months (range, 2–24 months). Epiphora subjectively improved in 90 (73%) of 123 systems, of which 27 (22%) of 123 were asymptomatic. In 33 systems (27%) in which epiphora persisted, 14 (11%) have undergone closed placement of a Jones canalicular bypass tube with control of symptoms.Conclusions
Retrograde canaliculostomy and intubation can spare a significant number of patients the long-term inconvenience of Jones tubes. Failure of this technique does not, however, compromise or complicate the future placement of a bypass tube. 相似文献6.
7.
BackgroundIron oxide (Fe3O4) nanoparticles (IO-NP) were recently employed in medical applications as a diagnostic tool and drug carrier. Photofrin (PF) is a photosensitizer that clinically is used in Photodynamic therapy (PDT).Study designThe photosensitivity of PF and Rose Bengal (RB) mixed with (IO-NP) on red blood cells (RBCs) lysis was investigated. Second, Photohemolysis for post-irradiation (delayed) and during irradiation (continuous) with PF, RB and IO-NP combinations at different concentrations was investigated. Third, the photohemolysis rate, relative lysis steepness and power-concentration dependant parameter were evaluated by modeling and fitting the data using Gompertz function and power law.MethodsRBCs were isolated from healthy male human volunteer. Washed cells (7.86 × 106 cells/mm3) were incubated with PF only or with IO-NP for 45 min at 37 °C then irradiated to a range of temperatures (4–41 °C). CPH results were recorded and evaluated using Gompertz function.ResultsThe relative steepness of the photohemolysis curves was approximately independent on light dose for delayed irradiation. The presence of IO-NP increases the rupturing time for 50% of the RBCs. Photohemolysis rate for delayed irradiation using the power law, led to 1.7 and 2.3 power dependence, respectively, for PF only and PF mixed with IO-NP. The power dependence of continuous irradiation measurements showed inverse proportionality for different concentrations of IO-NP combined with 2 μg/ml PF concentration and 1.5 μg/ml for RB concentration.ConclusionPhotosensitization of RBC with PF or RB mixed with IO-NP inhibited rupturing erythrocyte membrane and therefore a consideration should be taken against their combination in clinical applications. 相似文献
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10.
In this article we review the mechanism of ocular surface staining. Water-soluble dyes are excluded from the normal epithelium by tight junctions, the plasma membranes and the surface glycocalyx. Shed cells can take up dye. A proportion of normal corneas show sparse, scattered time-dependent, punctate fluorescein uptake, which, we hypothesise, is due to a graded loss of the glycocalyx barrier, permitting transcellular entry into pre-shed cells. In pathological staining, there is little evidence of ‘micropooling’ at sites of shedding and the term ‘punctate erosion’ may be a misnomer. It is more likely that the initial event involves transcellular dye entry and, in addition, diffusion across defective tight junctions. Different dye-staining characteristics probably reflect differences in molecular size and other physical properties of each dye, coupled with differences in visibility under the conditions of illumination used. This is most relevant to the rapid epithelial spread of fluorescein from sites of punctate staining, compared to the apparent confinement of dyes to staining cells with dyes such as lissamine green and rose bengal. We assume that fluorescein, with its lower molecular weight, spreads initially by a paracellular route and then by transcellular diffusion. Solution-Induced Corneal Staining (SICS), related to the use of certain contact lens care solutions, may have a different basis, involving the non-pathological uptake of cationic preservatives, such as biguanides, into epithelial membranes and secondary binding of the fluorescein anion. It is transient and may not imply corneal toxicity. Understanding the mechanism of staining is relevant to the standardisation of grading, to monitoring disease and to the conduct of clinical trials. 相似文献