Tape-stripping method in man: comparison of evaporimetric methods

BACKGROUND/PURPOSE: If the occlusion time of a closed chamber evaporimeter on the skin is too long, saturation might occur. We previously compared an open chamber and a closed chamber device on healthy volunteers. Comparable data on stripped skin with higher evaporation rates are not available. This study compares the sensitivity and correlation of open and closed chamber devices in a tape-stripping human model. The amount of tape removed SC was also quantified with a protein assay method. METHODS: Ten healthy volunteers (six male and four female; seven Caucasians and three Asian; mean age 38+/-16) were enrolled. In a randomized manner, one forearm was measured by an open chamber device and the opposite by a closed chamber device. After recording baseline measurements, 20 strippings were taken on each test site with tape disks. Transepidermal water loss (TEWL) was measured at the end of 10 and 20 tape strippings at each test site. Stratum corneum (SC) aggregates in the strips was assayed. RESULTS: The mean values obtained from two devices were similar after 10 trips and 20 strips. There was no statistically significant difference. The closed chamber device showed a slightly higher (but not significant) inter-individual coefficient of variation. SC aggregates in the strips were similar and without a statistically significant difference. CONCLUSION: The study suggests that both devices might yield similar TEWL values on stripped human skin in vivo.     

Modifications of the hydrophilicity of heterocyclic methacrylate copolymers for protein release

A series of copolymers comprising ethyl methacrylate (EM) and tetrahydrofurfuryl methacrylate (THFMA) gelled with either THFMA monomer or hydroxyethyl methacrylate (HEMA) monomer have been developed. In this paper, we examine the water uptake characteristics of the polymer systems and address the possibility of increasing the hydrophilicity of the systems by changing the ratios of the copolymers. We have investigated whether protein release from the polymers is related to the composition of the polymer systems. More protein was released from the polymers gelled with the more hydrophilic monomer (HEMA) than with THFMA. This was consistent with the calculated diffusion coefficients, which were 10 times greater for the polymers gelled with HEMA than those gelled with THFMA. Interestingly, the water uptake and protein release profiles were not dependent on the ratio of EM and THFMA in the copolymers. This is probably due to the conflicting roles of THFMA in the copolymer; it is both the more hydrophilic component as well as a cross-linking agent. In addition, it would appear that the structural and surface topography of these polymers had more significant effects on protein release than copolymer composition.     

Structure and Behavior in Hydrophilic Matrix Sustained Release Dosage Forms: 4. Studies of Water Mobility and Diffusion Coefficients in the Gel Layer of HPMC Tablets Using NMR Imaging

Purpose. The purpose of this study was to characterise the water mobility in the gel layer of hydrating HPMC tablets. Water mobility in the gel layer of different HPMCs was studied. Methods. NMR imaging, a non-invasive technique, has been used to measure the spatial distribution of self-diffusion coefficient (SDC) and T₂ relaxation times across the gel layer. Results. It has been shown that there is a water mobility gradient across the gel layer of HPMC tablets. Although SDC and T₂ relaxation times in the outer parts of the gel layer approached that of free water, in the inner parts they decreased progressively. Water mobility and SDC in the gel layer of different HPMCs appeared to vary with degree of substitution of the polymer and the lowest values were obtained across the gel layer of K4M tablets. Conclusions. Water mobility varies across the gel layer of hydrating HPMC tablets and it is dependent on the degree of substitution of the polymer.     

Inhibition of IgE formation in mice by glycoproteins from corn silk

The inhibitory effects of glycoproteins separated from a hot water extract of corn silk (U-CSE) on the formation of IgE antibodies after primarily and secondarily challenged responses with dinitrophenyl (DNP)-ovalbumin (OVA) antigen in mice were investigated using the passive cutaneous anaphylaxis (PCA) test. When U-CSE was given intranasally or intraperitoneally the day before primary immunization, IgE antibody production was strongly inhibited. Furthermore, it was found that new formation of IgE antibodies was readily inhibited by U-CSE administration in mice with high levels of IgE after primary immunization. It was also found that U-CSE markedly suppressed IgE antibody formation in secondarily challenged responses with the antigen. U-CSE may be clinically applicable to type I allergic diseases.     

Endotoxin transfer through dialysis membranes: small- versus large-pore membranes.

In this in-vivo study, dialysate and serum endotoxin was evaluated before and after haemodialysis with small-pore (PS400) and large-pore (PS600) polysulphone dialysers, and before and after haemodiafiltration with the PS600 filter. The source of the endotoxin was the presence in dialysate of Pseudomonads at a concentration of 10(3)-10(4) CFU/ml. Endotoxin was measured by a modified chromogenic limulus amoebocyte lysate (LAL) assay. In spite of dialysate endotoxin concentrations greater than 100 pg/ml, no changes in pre- versus posttreatment LAL reactivity were observed in PS400 dialysis and PS600 haemodiafiltration. In contrast, PS600 haemodialysis was related to an increase in serum LAL reactivity from 1.3 +/- 1.5 to 3.8 +/- 2.0 pg/ml (n = 15, P less than 0.01), and five patients (33.3%) showed a post-dialysis value in excess of 5 pg/ml. Our data are consistent with the absence of in-vivo endotoxin transfer during haemodialysis with small-pore dialyser membranes, and during haemodiafiltration with membranes with larger pores. An increase in LAL reactivity during haemodialysis with membranes with larger pores is, however, present, presumably due to the occurrence of backdiffusion/filtration with that specific strategy.     

苯DNA加合物研究进展(综述)

苯ＤＮＡ加合物研究进展（综述）李桂兰，常平综述徐伯洪审校（中国预防医学科学院劳动卫生与职业病研究所，北京１０００５０）我国职业接触苯的工人约有５０万，长期接触苯可引起白血病。苯与其它实质性肿瘤的问题也有报道［１，２］。世界癌症研究机构（ＩＡＲＣ）１９...     

Incidence of childhood diabetes mellitus in Yorkshire, northern England, is associated with nitrate in drinking water: an ecological analysis

Summary The relationship between the incidence of childhood-onset insulin-dependent diabetes mellitus and levels of nitrate in drinking water in the former Yorkshire Regional Health Authority was investigated by means of an ecological analysis. A population-based register contributed 1797 0–16-year-olds diagnosed with diabetes between 1978 and 1994. Nitrate data were based on 9330 samples of drinking water tested between 1990 and 1995 in 148 water supply zones, for which 1991 census small area statistics were taken on population density, ethnicity and socio-economic status. Diabetes incidence was positively associated with raised mean nitrate levels with a standardised incidence ratio of 115 in zones with greater than 14.85 mg · l^–1 (χ² = 26.81, 1 df, p < 0.001). Significant negative trends were found between standardised incidence ratios and proportion of non-whites in the population (χ² = 33.57, 1 df, p < 0.001), childhood population density (χ² = 30.81, 1 df, p < 0.001) and the Townsend deprivation score (χ² = 33.89, 1 df, p < 0.001). Poisson regression modelling, adjusting for the other factors, showed a significant increase in relative incidence rate ratio from a baseline of 1 at nitrate levels below 3.22 mg · l^–1 to 1.27 (95 % confidence interval 1.09,1.48) for mean nitrate levels above 14.85 mg · l^–1. An association between higher nitrate levels in domestic drinking water and incidence of childhood diabetes has been demonstrated. This was not explained by the ethnic composition of the population, population density or socioeconomic status. Nitrate in drinking water may be a precursor of chemicals which are toxic to the pancreas. [Diabetologia (1997) 40: 550–556] Received: 24 October 1996 and in revised form: 20 December 1996     

新型饮水对小鼠繁殖及抗氧化酶活性的影响

目的　探讨新型饮水对健康的影响及其保健作用。方法　将矿溶生态水、活化水、纯净水、矿泉水、碱性离子水等 5种新型饮水作为唯一水源分别喂饲亲代及子代小鼠 3个月 ,对照给予天然水。观察它们对小鼠体重、繁殖及抗氧化酶活性的影响。结果　与天然水比较 ,活化水、矿溶生态水促进亲代雄性小鼠体重增长 (P <0 0 5) ;矿溶生态水使子代小鼠、矿泉水和碱性离子水使子代雄性小鼠体重增长缓慢 (P <0 0 5) ;纯净水使新生仔鼠体重减轻 (P <0 0 5) ,活化水、矿溶生态水使小鼠窝产仔数增多 (P <0 0 5) ,5种水对小鼠受孕率、妊娠率、出生存活率无影响 ;矿溶生态水、活化水、纯净水、矿泉水使小鼠肝组织SOD活力升高 (P <0 0 5) ,碱性离子水使肝组织SOD活力降低 (P <0 0 5)。结论　 5种新型饮水对小鼠体重有影响 ,对受孕率、妊娠率、出生存活率无影响 ;矿溶生态水、活化水、纯净水、矿泉水有提高SOD活力作用