优选最佳数学模型用于固体制剂体外溶出实验数据处理程序的设计

程序由BASIC语言编写。对于固体制剂的体外溶出实验数据能从几种常用的数学拟合方法中提供最佳的数学模型予以拟合,用户选择或微机自选均可,使处理结果所提取的有关参数(T_50%,T_d等)与实验值更接近;并根据需要自行给出最恰当的时滞值。     

Seasonal variation and weather effects on road traffic accidents in Riyadh City

The monthly variation of Road Traffic Accidents (RTAs) in Riyadh city in the period 1989–1993 has been studied with reference to time of day, lighting conditions and prevalent weather conditions.Total RTA accidents were significantly more common, being directly correlated, with increased dry and wet bulb temperatures and significantly less common, being inversely correlated, with increased relative humidity and amount of precipitation of rain, snow, hail etc. However, RTAs recorded on rainy days only were significantly more common and directly correlated with precipitation (Note days of snow and hail are very rare in Riyadh city).Seasonal variation in RTAs was evident being maximal during the summer season particularly between 12 noon and 3 pm. This period is characterized by heavy traffic and intense sunlight. The role of hot weather prevalent in Saudi Arabia, where average temperatures of 34.4–34.7°C with maximum of 40–42.7°C are common in summer, have been suggested to be an important factor leading to increased stress and decreased performance of intellectual tasks which require considerable physical effort and motor skills. Increased heart rates, exacerbation of existing pathologic conditions such as heart disease and emphysema and loss of visual acuity have been reported. Consequently, prolonged exposure to heat must be considered as a hazard to the safety and health of drivers and a factor leading to an increased incidence of RTAs.     

Origins and implications of frequency-doubling in the visual evoked potential

The origins and implications of frequency-doubling (i.e., the dominance of the 4th-harmonic response instead of the reversal response) in the visual evoked potential (VEP) were investigated. Previous research demonstrated that frequency-doubling occurs in humans when sinusoidal but not square-wave luminance modulation is used to elicit the VEP, but little else is known about this intriguing phenomenon. Six adult humans viewed luminance and chromatic gratings that were presented using three different spatiotemporal combinations: 4 c/deg-3 Hz, 4 c/deg-6 Hz, and 12 c/deg-3 Hz. VEP's were recorded monopolarly from Oz using an ear reference and were subjected to a Fourier analysis. The results showed that frequency-doubling occurred only using sinusoidal luminance contrasts at 4 c/deg-3 Hz, although the relative strength of higher harmonic responses was greater for both sine- and square-wave luminance contrasts relative to their chromatic counterparts. Many hypotheses can be put forth to account for VEP frequency-doubling (none of which is entirely satisfactory); however, a plausible view is that this phenomenon is related to the magnocellular-parvocellular distinction. In general, the presence of frequency-doubling and other harmonic distortions may preclude the scalp-recorded steady-state VEP to suprathreshold luminance contrasts from describing accurately the spatiotemporal transfer characteristics of the human visual system.     

Vitamin D receptor and PCNA expression in severe parathyroid hyperplasia of uremic patients

Objective　To clarify the role of vitamin D receptor (VDR) expression in parathyroid proliferation and resistance of parathyroid glands to 1,25(OH)2D3 with secondary hyperparathyroidism (SHPT). Methods　This study used archive parathyroid with 7 uremic patients. The expression of proliferation cell nuclear antigen (PCNA) and VDR was evaluated in nineteen-surgically excised parathyroid tissues, including 11 diffuse hyperplasia (DH-type) and 8 nodular hyperplasia (NH-type) of parathyroid glands, by immunohistochemistry (avidin-biotin complex method). Results　The weight of parathyroid in SHPT was remarkably increased by 16.1 times. The numbers of parathyroid cells were increased by 1.86 times. The rate of PCNA was remarkably increased in parathyroid hyperplasia with SHPT compared with that in control group ［(6.35±3.36)‰ vs (1.73±1.31)‰, P<0.001］. The number of PCNA in DH-type was lower than that in NH-type (P<0.001). The density of VDR in the parathyroid with SHPT was significantly decreased ［(40.28±13.13)% vs (83.79±3.77)%, P<0.001］, VDR immunoreactivity expression in NH-type was lower than that in DH-type ［(27.14±4.12)% vs (49.84±7.33)%, P<0.001］. A significantly negative correlation was found between VDR density and the weight of the parathyroid (r=-0.46, P<0.05), the same as VDR and PCNA (r=-0.75, P<0.001). Conclusion　VDR density was significantly decreased in parathyroid tissue of uremic patients showing nodular hyperplasia compared with that in diffuse hyperplasia and there was significantly negative correlation between VDR density and the weight of the parathyroid, and this may contribute to the progression of SHPT. Furthermore, VDR deficiency may cause the resistance of parathyroid cells to 1, 25(OH)2D3, in part.     

阿司匹林锌的研制(Ⅰ)

目的研究阿司匹林锌的化学合成方法.方法以阿司匹林和硫酸锌为原料,经两步反应合成阿司匹林锌.结果得到的样品经IR、NMR、MS等波谱分析及元素分析、热分析证明该化合物为阿司匹林锌.总收率为80%.结论该合成方法收率稳定,合成周期短,合成路线完全可行.     

The fractionation, characterization, and subcellular localization of colony-stimulating activities released by the human monocyte-like cell line, GCT

GCT, a human monocyte-like cell line, has been shown to release biochemically distinct colony-stimulating activities (CSAs) for mouse and human marrows. These appear to be periodate-sensitive proteins with critical disulfide bonds. One, of molecular weight 145,000 daltons, stimulates macrophagic colony growth and is related to a 30,000-dalton molecule that also stimulates mouse growth. A 30,000-dalton CSA for human marrow can be separated from the 30,000-dalton mouse CSA by isoelectric focusing and gradient polyacrylamide gel electrophoresis. This distinction agrees with our previous finding of differential neutralization with anti-human urinary CSF antibody. The 30,000-dalton CSAs stimulate neutrophil, neutrophil-monocyte, and eosinophil colony growth in human marrow but only neutrophil and neutrophil-monocyte colonies in the mouse. Subcellular fractionation of GCT cells indicates that there are pools of preformed CSAs primarily associated with the cell cytosol that have similar apparent molecular weights to their secreted counterparts.