表面活性剂用于黄酮药物的薄层色谱分离鉴定的研究

以表面活性剂的胶束溶液为流动相的胶束色谱技术已引人重视,并已成功地应用于药物的薄层色谱分离鉴定。黄酮类化合物是中草药中广泛存在的一类有效成分。本文以十余种表面活性剂的胶束溶液为流动相研究了槲皮素、桑色素和芦丁的胶束薄层色谱行为,拟出了以4％Zeph—乙酰丙酮—水(5:1.5:1.5)溶液为流动相,聚酰胺薄膜为固定相分离此三种黄酮的层析体系,并对槐花进行分离和鉴定,得到了良好效果。     

In vivo comparison of three different porous materials intended for use in a keratoprosthesis

AIM—The goal was to compare the biological response of the corneal stroma with three porous materials: a melt blown microfibre web of polybutylene:polypropylene (80:20); a polyester spun laced fabric (polyethylene terephthalate), and an expanded polytetrafluoroethylene. Fifty per cent of each of the materials were modified using argon radio frequency.
METHODS—Discs (6 mm in diameter) were inserted into interlamellar stromal pockets and followed for a period of 12 weeks. Clinical evaluations were performed weekly. At 6 and 12 weeks, fibroplasia and the distribution of matrix proteins and growth factors (bFGF and TGF-β) were evaluated immunohistochemically. The characterisation of glycosaminoglycans was determined after selective extraction and digestion.
RESULTS—The response to the disc resembled that of a wound with a decrease in keratan sulphate and an increase in dermatan sulphate. Pretreatment of the discs reduced corneal oedema and neovascularisation. Heparan sulphate, not normally detected in the corneal stroma, was detected in the region immediately surrounding the disc and in the discs of some materials. The presence of glycosaminoglycans and collagens in the disc indicated that cells had migrated into the disc and deposited a complex matrix in all three materials. The collagen response was not surface specific. bFGF and TGF-β were detected in the region between the disc and the stroma in the polybutylene material and became diffuse with time.
CONCLUSION—Fibroplasia occurred most rapidly into the polyester discs but was accompanied by a large number of inflammatory cells. While the distribution of collagens was not altered by the material, the expression and distribution of growth factors was material dependent. bFGF was expressed transiently and occurred before that of TGF-β. It is predicted that the transient expression of growth factors mediates the regulation of matrix proteins.

Keywords: synthetic cornea; basic fibroblast growth factor; glycosaminoglycans; wound healing; cornea     

Mitochondrial HSP70, HSP40, and HSP60 bind to the 3' untranslated region of the Murine hepatitis virus genome

We have previously shown that mitochondrial-aconitase binds specifically to the 3' terminal 42 nucleotides of the Murine hepatitis virus (MHV) RNA along with three additional proteins of 70, 58 and 40 kDa to form a stable RNA-protein complex. Supershift and western blot assays have identified these three proteins as mitochondrial HSP70 (mtHSP70), HSP60, and HSP40. A series of co-immunoprecipitation assays have established that these four MHV RNA binding proteins are associated, even in the absence of MHV RNA. However, the presence of a synthetic RNA containing the sequence bound by these four proteins does increase the amount of co-precipitated protein, in particular the amount of HSP60 which is brought down with antibodies directed against HSP40 and mtHSP70. We have provided evidence for the interaction of these four proteins with the 3' end region of MHV RNA in infected cells by a series of immunoprecipitation RT-PCR assays. We believe it is likely that MHV RNA interacts with m-aconitase prior to its import into mitochondria in cooperation with extra-mitochondrial mtHSP70, HSP60, and HSP40.     

Endothelial findings in cryopreserved corneal transplants

Specular microscopy of the corneal endothelium was performed on 16 eyes that had undergone corneal transplantation using cryopreserved donor material seven months to nine years previously. The average cell count was 817 cells/mm2 with a range of 360 cells/mm2 to 1808 cells/mm2. Grafts from donors under 30 years of age which had a very short death to freezing time showed a higher endothelial cell density than grafts from older donors with a longer death to freezing time. The most prominent findings were very large, multinucleated endothelial cells that are thought to be the result of cell fusion.     

Development of a biopolymeric keratoprosthetic material. Evaluation in vitro and in vivo

Based on the results of in vitro and in vivo experiments, we have determined that the optimal material for the central transparent portion of a perforating keratoprosthesis is a polyvinyl alcohol copolymer hydrogel. The material supports the maintenance and growth of corneal epithelium in vitro as shown by population doublings and transmission electron microscopy. Discs preseeded with epithelial cells were cultured in vitro and transplanted into rabbit corneas. The proliferation of these cells in vivo was demonstrated using 3H-thymidine. Other experiments showed that the preseeded cells not only migrated from the central disc onto the peripheral rim of the host cornea but also that host peripheral epithelial cells migrated onto the anterior surface of the disc. The experiments described in this paper demonstrate that corneal epithelial cells preseeded onto hydrogel discs and transplanted into rabbit corneas remain adherent and are capable of proliferating.     

A systematic review of the effect of different models of after-hours primary medical care services on clinical outcome,medical workload,and patient and GP satisfaction

BACKGROUND: The organization of after-hours primary medical care services is changing in many countries. Increasing demand, economic considerations and changes in doctors' attitudes are fueling these changes. Information for policy makers in this field is needed. However, a comprehensive review of the international literature that compares the effects of one model of after-hours care with another is lacking. OBJECTIVE: The aim of this study was to carry out a systematic review of the international literature to determine what evidence exists about the effect of different models of out-of-hours primary medical care service on outcome. METHODS: Original studies and systematic reviews written since 1976 on the subject of 'after-hours primary medical care services' were identified. Databases searched were Medline/Premedline, CINAHL, HealthSTAR, Current Contents, Cochrane Reviews, DARE, EBM Reviews and EconLit. For each paper where the optimal design would have been an interventional study, the 'level' of evidence was assessed as described in the National Health and Medical Research Council Handbook. 'Comparative' studies (levels I, II, III and IV pre-/post-test studies) were included in this review. RESULTS: Six main models of after-hours primary care services (not mutually exclusive) were identified: practice-based services, deputizing services, emergency departments, co-operatives, primary care centres, and telephone triage and advice services. Outcomes were divided into the following categories: clinical outcomes, medical workload, and patient and GP satisfaction. The results indicate that the introduction of a telephone triage and advice service for after-hours primary medical care may reduce the immediate medical workload. Deputizing services increase immediate medical workload because of the low use of telephone advice and the high home visiting rate. Co-operatives, which use telephone triage and primary care centres and have a low home visiting rate, reduce immediate medical workload. There is little evidence on the effect of different service models on subsequent medical workload apart from the finding that GPs working in emergency departments may reduce the subsequent medical workload. There was very little evidence about the advantages of one service model compared with another in relation to clinical outcome. Studies consistently showed patient dissatisfaction with telephone consultations. CONCLUSIONS: The rapid growth in telephone triage and advice services appears to have the advantage of reducing immediate medical workload through the substitution of telephone consultations for in-person consultations, and this has the potential to reduce costs. However, this has to be balanced with the finding of reduced patient satisfaction when in-person consultations are replaced by telephone consultations. These findings should be borne in mind by policy makers deciding on the shape of future services.     

A socioeconomic profile of older adults with HIV

The objective of this study was to assess the socioeconomic circumstances of older patients with HIV and acquired immunodeficiency syndrome (AIDS). The investigators compared subjects from a national probability sample of 2,864 respondents from the HIV Cost and Services Utilization Study (HCSUS, 1996) with 9,810 subjects from Wave 1 (1992) of the Health and Retirement Survey (HRS). Bivariate analyses compare demographic characteristics, financial resources, and health insurance status between older and younger adults and between older adults with HIV and the general population. It was found that nearly 10% of the HIV-positive population is between the ages of 50 and 61 years. Older whites with HIV are mostly homosexual men who are more well educated, more often privately insured, and more financially stable than the HIV population as a whole. In contrast, older minorities with HIV possess few economic resources in either absolute or relative terms. The success of new drug therapies and the changing demographics of the HIV population necessitate innovative policies that promote labor force participation and continuous access to antiretroviral therapies.