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排序方式: 共有128条查询结果,搜索用时 15 毫秒
1.
Pigment changes in human skin after cryotherapy 总被引:2,自引:0,他引:2
We have investigated the changes in pigmentation and melanocyte distribution in human skin after a standardized freeze injury. All lesions developed hypopigmentation with a peripheral rim of hyperpigmentation. Abnormalities in pigmentation persisted for at least 6 months. Hyperpigmentation was predominantly an epidermal phenomenon. After brief freezes, hypopigmentation persisted despite the presence of functional melanocytes. After prolonged freezes, the consistent finding was an absence of melanosomes in keratinocytes, although melanocytes were present. We conclude that prolonged changes in skin color are frequent after brief freezes and that hypopigmentation is not synonymous with an absence of melanocytes. This suggests that hypopigmentation after the cryosurgical treatment of malignant melanocytic tumors may not equate with cure. 相似文献
2.
G A Conder L F Mayberry J R Bristol G A Castro B L Lee D D Kratzer S D Folz D L Rector 《Prostaglandins》1987,34(6):817-827
PGE1 and PGE2 have been reported to enhance natural expulsion of Nippostrongylus brasiliensis, a nematode parasite, from the intestine of the rat. Mucus production may also be a key element of worm rejection. Our study attempts to determine if 1) PGE1 or PGE2 alter the normal course of infection with N. brasiliensis in rats, 2) a known mucous enhancing drug, acetazolamide, can augment the rate of worm expulsion, and 3) combinations of prostaglandins and acetazolamide affect N. brasiliensis in the rat. Rats were inoculated with approximately 1,000 infective larvae of N. brasiliensis. Animals were administered, intraduodenally, one of the following: 0.2 ml 0.9% NaCl; 0.2 ml 100% ethanol; 250 micrograms PGE1/0.2 ml 100% ethanol; 250 micrograms PGE2/0.2 ml 100% ethanol; 250 micrograms acetazolamide/0.2 ml 100% ethanol; 250 micrograms PGE1 or PGE2 + 250 micrograms acetazolamide/0.2 ml 100% ethanol. These solutions were given in a single bolus on day 6 postinoculation (PI) or twice daily on days 6-9 PI. Following these treatments the number of parasite ova per gram feces per day for days 6-10 PI and numbers of worms present at necropsy on day 10 PI were determined. Treatment with prostaglandins or acetazolamide or both failed to adversely affect egg deposition by adult female worms or the number of worms in the small intestine. These results do not support the involvement of prostaglandins in the expulsion of N. brasiliensis from the host intestine. 相似文献
3.
J B Bristol P M Emmett K W Heaton R C Williamson 《BMJ (Clinical research ed.)》1985,291(6507):1467-1470
The habitual diet of 50 patients with large bowel cancer, as assessed by a dietary history method, was compared with that of 50 closely matched controls. Patients were included only if their symptoms were unlikely to have changed previous eating habits. The mean daily intakes of all major nutrient classes and of dietary fibre were estimated. Patients with large bowel cancer consumed 16% more energy than controls (mean (SEM) daily intake 9.92 (0.41) v 8.56 (0.32) MJ (2370 (98) v 2046 (76) kcal), respectively; p less than 0.0001), mainly in the form of carbohydrate (21% more; 282.6 (13.7) v 233.4 (10.5) g; p less than 0.0001) and fat (14% more; 100.8 (4.3) v 88.4 (3.2) g; p less than 0.001). The extra carbohydrate was largely in the form of sugars depleted in fibre and the extra fat as combinations of fat and such sugars. As the selection criteria used make it unlikely that this eating pattern was caused by the disease the data suggest that a high intake of sugars depleted in fibre and fat predisposes to the development of large bowel cancer. 相似文献
4.
5.
The long arm of chromosome 4D of wheat (Triticum aestivum L.) contains a gene (or genes) which influences the ability of wheat plants to discriminate between Na+ and K+. This discrimination most obviously affects transport from the roots to the shoots, in which less Na+ and more K+ accumulate in those plants which contain the long arm of chromosome 4D. Concentrations of Na+ and K+ in the roots, and Cl− concentrations in the roots and shoots, are not significantly affected by this trait, but Na+, K+ and Cl− contents of the grain are reduced. The trait operates over a wide range of salinities and appears to be constitutive. At
the moment it is not possible to determine accurately the effect of this trait on growth or grain yield because the aneuploid
lines which are available are much less vigorous and less fertile than their euploid parents. 相似文献
6.
Eighty-four 18-month-old crossbred beef heifers, 3 to 4 months pregnant, were assigned by stratified randomization to either a high or low (control) beta-carotene (B-car) diet to determine the effect of long-term supplementation of B-car on reproductive performance. The heifers were followed through pregnancy, calving and subsequent breeding. The basal diet consisted of barley, canola meal and barley straw. Heifers supplemented by B-car received 625 mg B-car per day in the concentrate. Vitamin A and D complex injections were given monthly to all heifers. Heifers were bred by artificial insemination after Day 60 postpartum. Throughout the study heifers fed the B-car supplement had higher levels of B-car in plasma (> 300 ug/dl) (P < 0.01) than the heifers fed the control diet (< 50 ug/dl). Vitamin A status was satisfactory in all heifers throughout the study. Birth weight of calves, weight gain, and incidence of mortality were not influenced by B-car. For the control and B-car treatments, days postpartum to first normal luteal phase were 67.5 and 62.6 days; days postpartum to first detected estrus were 70.1 and 65.3, and services per conception were 1.24 and 1.29, respectively. Long-term supplementation of B-car increased prepartum plasma progesterone but had no effect on postpartum fertility. 相似文献
7.
Rachel M. Bristol Rachel Tucker Deborah A. Dawson Gavin Horsburgh Robert P. Prys‐Jones Alain C. Frantz Andy Krupa Nirmal J. Shah Terry Burke Jim J. Groombridge 《Molecular ecology》2013,22(18):4644-4662
Re‐introduction is an important tool for recovering endangered species; however, the magnitude of genetic consequences for re‐introduced populations remains largely unknown, in particular the relative impacts of historical population bottlenecks compared to those induced by conservation management. We characterize 14 microsatellite loci developed for the Seychelles paradise flycatcher and use them to quantify temporal and spatial measures of genetic variation across a 134‐year time frame encompassing a historical bottleneck that reduced the species to ~28 individuals in the 1960s, through the initial stages of recovery and across a second contemporary conservation‐introduction‐induced bottleneck. We then evaluate the relative impacts of the two bottlenecks, and finally apply our findings to inform broader re‐introduction strategy. We find a temporal trend of significant decrease in standard measures of genetic diversity across the historical bottleneck, but only a nonsignificant downward trend in number of alleles across the contemporary bottleneck. However, accounting for the different timescales of the two bottlenecks (~40 historical generations versus <1 contemporary generation), the loss of genetic diversity per generation is greater across the contemporary bottleneck. Historically, the flycatcher population was genetically structured; however, extinction on four of five islands has resulted in a homogeneous contemporary population. We conclude that severe historical bottlenecks can leave a large footprint in terms of sheer quantity of genetic diversity lost. However, severely depleted genetic diversity does not render a species immune to further genetic erosion upon re‐introduction. In some cases, the loss of genetic diversity per generation can, initially at least, be greater across re‐introduction‐induced bottlenecks. 相似文献
8.
Emilie M. M. Santos Wiro J. Niessen Albert J. Yoo Olvert A. Berkhemer Ludo F. Beenen Charles B. Majoie Henk. A. Marquering MR CLEAN investigators 《PloS one》2016,11(1)
Background and Purpose
In acute ischemic stroke (AIS) management, CT-based thrombus density has been associated with treatment success. However, currently used thrombus measurements are prone to inter-observer variability and oversimplify the heterogeneous thrombus composition. Our aim was first to introduce an automated method to assess the entire thrombus density and then to compare the measured entire thrombus density with respect to current standard manual measurements.Materials and Method
In 135 AIS patients, the density distribution of the entire thrombus was determined. Density distributions were described using medians, interquartile ranges (IQR), kurtosis, and skewedness. Differences between the median of entire thrombus measurements and commonly applied manual measurements using 3 regions of interest were determined using linear regression.Results
Density distributions varied considerably with medians ranging from 20.0 to 62.8 HU and IQRs ranging from 9.3 to 55.8 HU. The average median of the thrombus density distributions (43.5 ± 10.2 HU) was lower than the manual assessment (49.6 ± 8.0 HU) (p<0.05). The difference between manual measurements and median density of entire thrombus decreased with increasing density (r = 0.64; p<0.05), revealing relatively higher manual measurements for low density thrombi such that manual density measurement tend overestimates the real thrombus density.Conclusions
Automatic measurements of the full thrombus expose a wide variety of thrombi density distribution, which is not grasped with currently used manual measurement. Furthermore, discrimination of low and high density thrombi is improved with the automated method. 相似文献9.
Towards a framework for the evolutionary genomics of Kinetoplastids: what kind of data and how much?
The current status of kinetoplastids phylogeny and evolution is discussed in view of the recent progresses on genomics. Some ideas on a potential framework for the evolutionary genomics of kinetoplastids are presented. 相似文献
10.