Brightness discrimination and contrast sensitivity in chronic glaucoma--a clinical study.

The visual acuity, the difference in sensitivity of the two eyes to light (brightness ratio), and contrast sensitivity were assessed in 28 patients with chronic open angle glaucoma and compared with those of 41 normal controls of similar ages and visual acuity. The results obtained were related to the results of Tübingen visual field analysis in patients with glaucoma. Twenty-four of the 28 glaucoma patients (86%) had a significant disparity in brightness ratio between the two eyes. This was found to match the frequency of visual field loss. Moreover, there was a significant relationship between the interocular differences in brightness sense and the difference in the degree of visual field loss between the two eyes. Of the glaucoma patients 39% had sum contrast sensitivities outside the normal range for age-matched normal controls. No significant correlation was found between the interocular difference in brightness sense and the visual acuity or the interocular difference in sum contrast sensitivity. It is concluded that, in the presence of a normal visual acuity, the brightness ratio test warrants evaluation as a potential screening test for chronic open angle glaucoma.     

亚硒酸钠诱导白内障的机理研究

在pH8.0-8.5条件下,谷胱甘肽、氧或过氧化氢过量时,微量的10~(-4)mol·L~(-1)亚硒酸钠能使鲁米诺产生稳定的化学发光。发光强度依赖于酸度、谷胱甘肽浓度、氧及过氧化氢的浓度。超氧化物歧化酶(SOD)对鲁米诺发光有明显的抑制作用。SeO_3~(2-)在眼内催化产生活性氧可能是产生白内障的原因。     

Immunogold localisation of laminin in normal and exfoliative iris.

Immunoelectron microscopic studies of exfoliative iris tissue (seven specimens) revealed the presence of laminin in the fibrillar component of exfoliation material. The immunogold label was uniformly distributed on the exfoliation fibres. Deposition of laminin labelled exfoliation material in the dilator muscle was a noteworthy feature, as was an apparent depletion of laminin in the basement membranes of ostensibly unaffected vessels. In control iris tissue (five enucleated eyes) laminin was identified in the basement membrane round vascular contractile cells, but not beneath the endothelium.     

Biocatalytic synthesis of acrylates in supercritical fluids: tuning enzyme activity by changing pressure.

Supercritical fluids are a unique class of nonaqueous media in which biocatalytic reactions can occur. The physical properties of supercritical fluids, which include gas-like diffusivities and liquid-like densities, can be predictably controlled with changing pressure. This paper describes how adjustment of pressure, with the subsequent predictable changes of the dielectric constant and Hildebrand solubility parameter for fluoroform, ethane, sulfur hexafluoride, and propane, can be used to manipulate the activity of lipase in the transesterification of methylmethacrylate with 2-ethyl-1-hexanol. Of particular interest is that the dielectric constant of supercritical fluoroform can be tuned from approximately 1 to 8, merely by increasing pressure from 850 to 4000 psi (from 5.9 to 28 MPa). The possibility now exists to predictably alter both the selectivity and the activity of a biocatalyst merely by changing pressure.     

Increased prevalence of undernutrition in Parkinson's disease and its relationship to clinical disease parameters

Summary An anthropometric study was performed in 95 subjects (53 male, 42 female) with Parkinson's disease. Weight, height, triceps and biceps skin-fold thicknesses, and mid-arm circumference were recorded. A high incidence of undernutrition was found (23.6% of males and 22.5% of females, as defined by recent British guidelines). A subgroup of severely disabled patients with Parkinson's disease had a significantly lower mean body mass index than a similarly disabled control group with chronic pyramidal upper motor neuron lesions (males 20.6v 23.2 kg/m² p<0.05; females 20.6v 26.6 kg/m² p<0.01), suggesting that the undernutrition is not due to chronic illness or immobility alone. Correlation between anthropometric indices and clinical features of disease demonstrated that the presence of moderate or severe dyskinetic movements was the clinical parameter most strongly related to undernutrition. The reduction in anthropometric indices was most marked for skin fold thickness (related to percentage body fat) and least for arm muscle circumference (related to lean body mass); therefore the weight loss seen in Parkinson's disease is primarily due to fat loss rather than muscle loss.     

大鼠气管上皮细胞体内—体外转化模型的研究

本研究建立了大鼠气管上皮细胞体内－体外转化模型，大鼠气管内滴注苯并芘，三天后处死大鼠，消化气管上皮细胞，接种于无血清完全培养基。细胞形成集落后，换为选择培养基继续培养五周，统计转化率。结果显示，２５ｍｇ／ｋｇ和５０ｍｇ／ｋｇ的苯并芘可诱导大鼠气管上皮细胞转化及微核增加，用同样方法研究了煤焦沥青提取物，结果表明，剂量为８ｍｇ／ｋｇ和２５ｍｇ／ｋｇ的煤焦沥青提取物能明显诱导大鼠气管上皮细胞转化。