Inter- and intra-individual variability of non-invasive tear break-up time in Hong Kong Chinese

Non-invasive tear break-up time (NITBUT) has been proposed as a measure of tear film integrity which is superior to the more commonly used tear break-up time (TBUT), since it does not alter the volume or the physicochemical properties of the tear layer by the addition of fluorescein. We measured NITBUT by measuring the time taken for distortions or discontinuities to appear in the reflected image of a grid pattern which covered about 80 per cent of the corneal surface. NITBUT measures were made 100 times on seven Hong Kong Chinese subjects with up to 20 consecutive measures being made on a single day. We also measured NITBUT on one occasion on an unselected population of 52 Hong Kong Chinese subjects. NITBUT shows a skewed distribution in all subjects, with many shorter values and some extremely long values. There are statistically significant variations in NITBUT from day to day, and from subject to subject. The group of 52 subjects also had a skewed NITBUT distribution with many short values and some very long values. The arithmetic mean does not adequately represent NITBUT data, either for individual subjects or for this group of subjects. As many as five to eight measures may be necessary to gain a stable estimate of the NITBUT and stability of the measure is improved if extreme values are omitted. We recommend the use of nonparametric statistics to compare NITBUT values from day to day in or between subjects.     

Periodontal conditions among the middle-aged and the elderly in Hong Kong

Abstract The aim of this study was to describe the periodontal conditions in 372 35–44-yr-old and 537 noninstitutionalized 65–74-yr-old Hong Kong Chinese who were examined clinically for loss of attachment, recession, probing depth, calculus, and bleeding after probing. Community Periodontal Index (CPI) data and treatment need indications were compiled from index teeth or their substitutes. The prevalence of loss of attachment varied considerably in both cohorts according to the definition of the threshold (≥6, ≥9, and ≥12 mm, respectively). The mean numbers of teeth with loss of attachment at the ≥6-mm threshold and at higher thresholds were small. In both age cohorts, about one-fifth of subjects had probing depths ≥6-mm, while al the ≥9-mm threshold only 2–3% were so affected. Although recession was an important component of loss of attachment in the younger cohort, in the older cohort the prevalence and extent of recession were greater than for probing depths at thresholds ≥4 mm. All subjects had one or more teeth with calculus, bleeding, or both, most teeth being so affected. Eighty-four of the 537 65–74-yr-old subjects were excluded either because of edentulousness or because extractions indicated for the remaining teeth would have rendered the subjects edentulous. The distribution of subjects according to their highest CPI score was remarkably similar for the two cohorts. No subjects in either age group were assessed as “healthy” (CPI code 0) or had “bleeding only” (code 1) as their highest score. While most subjects scored CPI code 2 or 3 us their highest score, only 17% of the younger and 15% of the older cohort scored Community Periodontal Index of Treatment Needs (CPITN) code 4. Differences in the mean number of sextants affected by CPI codes between the two cohorts were mainly due to a greater number of excluded sextants in the older cohort. CPI findings for 35–44-yr-olds differed little from those reported in 1984.     

Morphological types of ganglion cells in the dog and wolf retina.

The morphological types of ganglion cells in the dog and wolf retina were studied by intracellular staining with Lucifer Yellow. These retinae contain a range of ganglion cell types that closely correspond to those found in cat retina: alpha cells with large somata and large, relatively densely branched dendritic trees; beta cells with medium-sized somata and small, densely branched dendritic trees; and a variety of other types with smaller somata and varying dendritic branching patterns and dendritic field sizes. The correspondence of canine and cat ganglion cell types strengthens the view that there is a common set of ganglion cell types in carnivores. Alpha and beta cell dendritic trees of dog and wolf are monostratified in either the inner or the outer part of the inner plexiform layer, suggesting an on/off dichotomy in the response to light. Dendritic field sizes of dog alpha and beta cells increase from the central area to peripheral retina: alpha cell fields from 160-200 microns to about 1,100 microns diameter, and beta cell fields from 25 microns to about 360 microns diameter. These sizes are quantitatively very similar to those found in cat retina. The close qualitative and quantitative morphological correspondence of cat and dog ganglion cells suggests that they are also functionally very similar. It is likely that dog alpha cells have brisk-transient (Y), and dog beta cells brisk-sustained (X) concentric receptive fields. From the smallest beta cell sizes it is concluded that the visual acuity of the dog may be as good as that of the cat.     

Influences of context on early writing development

Research on children's early writing development in the past has focused primarily on product and process. In reviewing the more recent research on early writing development, however, a new focus of context emerges. Occurrences of literacy are now being observed in the home, the school, and the community. With this new emphasis, comes the task of defining context. A definition of context reflects theoretical perspectives, areas of research interests, and types of methodologies employed in conducting research. Therefore, the purpose of this article is to address the following aspects of context: #op1#cp multidiscipline perspectives and definitions of context, #op2#cp contextual shifts observed between the home and the school, #op3#cp contextual factors present when learning how to write, and #op4#cp pedagogical implications for curriculum development.     

Surface behavior of axolemma monolayers: Physico-chemical characterization and use as supported planar membranes for cultured Schwann cells

The axolemma membrane forms a stable and reproducible monomolecular layer at the air-aqueous interface. The major lipids and proteins are present in this monolayer in molar ratios similar to the original membrane. Acetylcholinesterase and Na-K-ATPase activities are preserved in the monolayer to levels of 64% and 25%, respectively. The total lipid fraction forms a homogeneously mixed phase. The presence of proteins in the monolayer introduces surface inhomogeneties. Among other features, this is revealed by the presence of two values of lateral pressure at which the monolayer shows partial or total collapse: a broad partial collapse at surface pressures between 13 to 30 mN/m and a sharp collapse point at 46 mN/m. The average molecular areas, the broad collapse point, and the variation of the surface potential per molecule suggest the relocation of protein components at surface pressures between 13 to 30 mN/m. The behavior is consistent with the extrusion and exposure of proteins toward the aqueous medium that depends on the lateral pressure. Schwann cells grown on coverslips coated with axolemma monolayers at 13 mN/m (beginning of the broad collapse) and 34 mN/m (above the broad collapse) recognize the difference in the surface organization of axolemma caused by the lateral pressure which affects their proliferation, morphology, and spatial pattern of organization. Our results show for the first time that response of Schwann cells depends on the intermolecular organization of the axolemma surface with which they interact. These results suggest that the local expression of putative surface molecules of axolemma that may mediate membrane recognition and the signalling of morphological and proliferative changes can be modulated by long range supramolecular properties. © 1993 Wiley-Liss, Inc.     

重组人红细胞生成素治疗肾性贫血的临床分析

目的　观察重组人红细胞生成素 (RhEPO)对肾性贫血的治疗作用。方法　根据使用EPO剂量的不同将 39例慢性肾衰竭并血液透析病人分成 4组 ,观察治疗后 2、4、12个月时与治疗前 (0月 )相比红细胞数 (RBC)、红细胞比积 (Hct)及血红蛋白含量 (Hb)的变化。结果　 2 4例使用EPO10 0 - 15 0IU/ (kg·w) (6 0 0 0IU/w - 90 0 0IU/w) ,治疗后RBC、Hct、Hb较治疗前有显著升高 (P≤ 0 .0 0 1) ;5例使用EPO5 0IU/ (kg·w) (30 0 0IU/w) +间断输血患者 ,其RBC、Hct、Hb升高不显著 ;10例不用EPO而单纯输血患者 ,其RBC、Hct、Hb无明显变化 (P >0 .0 5 )。结论　EPO能较好地纠正肾性贫血 ;单纯输血不能治疗肾性贫血     

铲状电极经尿道前列腺电汽化切割术120例报告

目的：探讨铲状电极经尿道前列腺电汽化切割术中的手术经验及疗效。方法：总结了120例经尿道前列腺电汽化切割手术的治疗资料。结果：术后随访1月～2年，120倒手术患者118例治愈，2例于术后出现急性肾衰，经保守对症治疗痊愈，2例出现压力性尿失禁，经对症治疗好转。结论：铲状电极行前列腺组织的汽化切割，优于滚轮汽化电极或电极弧，术中术后出血少，术中术野清晰，安全可靠。