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31.
化学染发剂和冷烫精的毒性及对人体健康影响的调查研究 总被引:7,自引:1,他引:6
本文通过化学染发剂和冷烫精对大白鼠骨髓多染红细胞,毛囊细胞的微核实验及人群健康影响调查,结果表明化学染发剂,冷烫清具有较强致突变作用,两者同时使用致突变明显增强,并提出研制高效无毒染发剂和加强防护的重要性。 相似文献
32.
LYNDA E ALBERTYN 《Journal of Medical Imaging and Radiation Oncology》1992,36(1):17-22
Both systemic and local therapy, for conditions of the breast and unrelated to it, may produce manuno-graphic changes. Some of these are characteristic, such as the pattern of scarring seen in reduction mammo-plasty. In many other instances, however, the changes produced overlap features commonly seen in malignancy. A knowledge of the timing, natural history and spectrum of these changes will aid mammographic interpretation. 相似文献
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34.
Systolic and diastolic blood pressures were measured on 254 monozygotic (MZ) and 260 dizygotic (DZ) male twin pairs, during middle age (average age 48 years) and at two later age points. Genetic and environmental components of covariation were modeled by time series. For both measures, shared environmental influences were absent and specific environmental influences were largely time-specific. Although heritability was about 0.5 at each time point, genetic variation present at middle age contributed only about 60% to that present 9 years later, the remaining 40% being new. Fifteen years later, at the third time point, no new genetic variation was evident, variation in individual differences being entirely attributable to genetic differences laid down at the two earlier ages. © 1993 Wiley-Liss, Inc. 相似文献
35.
Stuart A. Batterman Alfred Franzblau Nanzheng Zhou 《International archives of occupational and environmental health》1996,68(4):268-274
Dermal exposures of methanol were administered in a clinical study designed to compare several biological indicators. Four
subjects were exposed in five exposure sessions of varying length. In each session, a sequence of measurements of methanol
concentrations in blood, breath, and headspace samples of air at exposed and unexposed skin were collected before and after
dermal exposures. Skin headspace samples, collected in gas sampling bags, were designed to reflect equilibrium skin: air partitioning.
At exposed skin, headspace samples were highly elevated for at least 8 h following exposure, indicating the presence of a
methanol reservoir in skin. After exposure, methanol concentrations at exposed skin showed a rapid initial decline, then a
slower first-order decrease. Methanol concentrations were clearly detectable in headspace samples at unexposed skin. Substantial
transfer from exposed skin occurred due to mechanical contact and washing. When transfer was restricted, surface concentrations
at unexposed skin were similar to levels in breath and were strongly correlated to methanol concentrations in blood. While
results are preliminary due to the small sample sizes and several unresolved experimental issues, the simple, rapid, and noninvasive
skin headspace measurements appear useful as a biological exposure indicator that clearly shows the presence and site of a
dermal exposure, and measurements at unexposed skin reflect concentrations in blood.
Received: 14 March 1995/Accepted: 3 November 1995 相似文献
36.
M N Martinez F R Pelsor V P Shah J P Skelly I L Honigberg S M Hemingway J M Gallo J A Kotzan R Zaman W J Brown 《Biopharmaceutics & drug disposition》1990,11(1):17-29
Quinidine gluconate 324 mg sustained release tablets (Quinaglute) was administered as a single dose to 15 healthy male subjects following an overnight fast, immediately following a high fat (HF) breakfast or immediately following a low fat (LF) breakfast. Serum samples were obtained over a 48 h period and analyzed for quinidine content using a high performance liquid chromatographic assay. Under the conditions of the study, both the rate and extent of quinidine bioavailability was significantly affected by food. The extent of bioavailability was statistically significantly greater (p less than 0.05) following both the HF and LF meals as compared to that in the fasted state. Rate of bioavailability was significantly enhanced following the LF meal as compared to that of the other two treatment groups. Although peak concentrations were greater and time to peak concentrations somewhat later following the HF meal versus those under fasting conditions, these differences were not statistically significant. In addition, the characteristics of the serum concentration-time profile (as defined by the number, magnitude, and time of occurrence of the multiple absorption maxima) was unique for each of the three treatment groups. Possible mechanisms underlying these results are explored. 相似文献
37.
Automatic assessment of levodopa-induced dyskinesias in daily life by neural networks. 总被引:1,自引:0,他引:1
We developed an objective and automatic procedure to assess the severity of levodopa-induced dyskinesia (LID) in patients with Parkinson's disease during daily life activities. Thirteen patients were continuously monitored in a home-like situation for a period of approximately 2.5 hours. During this time period, the patients performed approximately 35 functional daily life activities. Behavior of the patients was measured using triaxial accelerometers, which were placed at six different positions on the body. A neural network was trained to assess the severity of LID using various variables of the accelerometer signals. Neural network scores were compared with the assessment by physicians, who evaluated the continuously videotaped behavior of the patients off-line. The neural network correctly classified dyskinesia or the absence of dyskinesia in 15-minute intervals in 93.7, 99.7, and 97.0% for the arm, trunk, and leg, respectively. In the few cases of misclassification, the rating by the neural network was in the class next to that indicated by the physicians using the AIMS score (scale 0-4). Analysis of the neural networks revealed several new variables, which are relevant for assessing the severity of LID. The results indicate that the neural network can accurately assess the severity of LID and could distinguish LID from voluntary movements in daily life situations. 相似文献
38.
39.
Porcine models have been used extensively for skin flap research because of the established similarity between the cutaneous
blood supply of the swine and humans. The Yucatan minipig provides an excellent model for researching the properties of random
cutaneous flaps, offering several advantages over other breeds of swine. In this study, a total of 67 random cutaneous dorsal
flank flaps measuring 4 × 14 cm were raised on nine Yucatan minipigs. The mean survival length (10.03 ± 1.60 cm) of the nondelayed
flaps was greater than others reported in the literature. The well-defined plane between the subcutaneous tissue and the panniculus
carnosus facilitated flap elevation consistently above the level of the panniculus carnosus thereby ensuring the creation
of a true random cutaneous flap. Furthermore, the hairless nature of the skin, particularly beneficial in studying chemical
peels, permits easy visualization and monitoring of any external skin changes. These advantages make the Yucatan minipig a
more desirable alternative to other breeds of swine for use in skin flap research. 相似文献
40.
L. Paczek J. Pazik M. Teschner R. M. Schaefer W. Rowinski J. Szmidt K. Abgarowicz L. Gradowska M. Morzycka-Michalik A. Heidland 《Transplant international》1994,7(S1):311-313
Abstract The major reason for late graft losses is chronic rejection. Recently, a large number of studies have indicated that proteolytic enzymes play an important role as mediators of glomerular injury. The cysteine proteinases cathepsins B and L degrade structural matrix proteins such as type I collagen and laminin. We investigated intraglomerular protease activities in 12 patients after kidney graftectomy because of end-tage renal disease following chronic rejection. A group of 12 patients undergoing nephrectomy because of cancer served as controls using only non-involved parts of the kidney. The activities of cathepsins B and L in homogenates of isolated glomeruli were measured fluorometrically methylcoumarylamidc substrates and related to DNA content. In rejected kidney allografts we observed significantly enhanced intraglomerular cathepsin B activity and cathepsin B + L activity. 相似文献