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排序方式: 共有1639条查询结果,搜索用时 15 毫秒
101.
Madden MC Dailey LA Stonehuerner JG Harris BD 《Journal of toxicology and environmental health. Part A》2003,66(24):2281-2297
Epidemiologic evidence suggests that increased morbidity and mortality are associated with the concentrations of ambient air particulate matter (PM). Many sources contribute to the particulate fraction of ambient air pollution, including diesel exhaust particulates (DEP). Diesel exhaust also contributes gas-phase pollutants to the atmosphere, and gaseous copollutants may influence the toxicity of PM. The composition of diesel exhaust varies greatly depending on the engine load conditions as well as other factors. To determine whether different diesel exhaust composition can affect lung cell resposes, the effects of of diesel exhaust extracts derived from different engine loads were examined on normal human bronchial epithelial cells (NHBE) in vitro. Diesel exhaust was collected into chilled impingers containing phosphate-buffered saline (PBS). Cultured NHBE cells were treated with 0 to 500 microg/well extract from approximately 0% engine load (termed low load or LL) or extract from approximately 75% engine load (termed high load or HL) for 24 h. The HL extract was cytotoxic at 500 microg compared to controls as measured by (51)Cr release. Production of the neutrophil chemotaxin interleukin 8 (IL-8) was decreased 4.7-fold in cells treated with 500 microg LL extract, whereas cells treated with 500 microg HL extract showed a 2.4-fold increase in IL-8 release. Production of the inflammatory and immune system mediator prostaglandin E(2) (PGE(2)) was increased up to 2.5-fold in cells treated with HL extract, but unchanged with other treatments. Melittin stimulation of cells showed that the LL extract had an inhibitory effect on PGE(2) release at 500 microg. Differences in carbonyl content of the extracts were found by high performance liquid chromatography/mass spectroscopy HPLC/MS, with the HL extract having more intermediate size carbonyls (i.e. with six to nine carbons). The data suggest that the response of NHBE cells to treatment with diesel exhaust will vary depending on the constituent components of the exhaust. 相似文献
102.
PURPOSE: Infantile myofibromatosis is an uncommon tumor that occurs rarely in the periorbit and orbit. This article reports two cases of infantile myofibromatosis of the orbital adnexa and describes the associated clinical, histopathologic, and immunohistochemical findings. DESIGN: Two retrospective, interventional case reports with clinicopathologic correlation. INTERVENTION: Treatment consisted of excision of the tumors. MAIN OUTCOME MEASURES: Histologic and immunohistochemical evaluation and clinical evaluation for tumor recurrence. RESULTS: The first patient was a newborn male with a large tumor extending from his eyelid that was excised at day 2 of life. Histologic and immunohistochemistry analyses were used to make a diagnosis of infantile myofibromatosis. He remains disease free at age 7 years. The second case was a 6-year-old boy with a 1-month history of proptosis resulting from an orbital mass. Incisional biopsy revealed a tumor consistent with infantile myofibromatosis. He remains tumor free 12 months after complete gross surgical resection. CONCLUSIONS: Infantile myofibromatosis is an uncommon tumor that is rare in the orbit. Differential diagnosis can be difficult based solely on histologic analysis. Immunohistochemistry evaluation demonstrating cytoplasmic actin filaments within neoplastic spindle cells confirms the diagnosis. As soon as the diagnosis is made, chest and abdominal imaging is of value to define the prognosis and to direct further treatment. After the diagnosis of nonvisceral infantile myofibromatosis, complete gross resection, if possible, is the treatment of choice. 相似文献
103.
PURPOSE: To compare graft contraction rates of acellular dermis versus hard palate mucosa when used as free spacer grafts in lower eyelid surgery and to provide clinical outcome data. METHODS: A prospective, nonrandomized clinical trial involving the placement of 19 spacer grafts in the lower eyelids of 14 patients was performed. Indications for spacer graft placement included lower eyelid retraction and mildly contracted socket. Patients with lower eyelid retraction also underwent an endoscopic subperiosteal midface lift. For all procedures, the height of each graft was measured during and after surgery. The amount of contraction was measured for each graft, and a mean was calculated for each spacer material. The clinical success was evaluated for all procedures, based on improvement of the functional concern being addressed. RESULTS: The mean graft contraction rate was 57% for the acellular dermis and 16% for the hard palate mucosal grafts (P <0.005). Of the 7 procedures using acellular dermis for lower eyelid retraction, 6 were considered a success, and 1 was considered a partial success. Of the 6 procedures using hard palate for lower eyelid retraction, 5 were considered a success, and 1 was considered a failure unrelated to the graft. Of the 5 procedures with acellular dermis used for mildly contracted socket, 2 were considered a success, 2 were considered a partial success, and 1 was considered a failure because of graft contraction. The one case using hard palate for mildly contracted socket was considered a success. CONCLUSIONS: Acellular dermis contracts significantly more than hard palate mucosa when used as a lower eyelid spacer graft. Acellular dermis and hard palate mucosa were both associated with a high rate of clinical success in all categories except for patients with a mildly contracted socket who received acellular dermis; more than 60% of these patients (n=5) had only partial success or failure caused by graft contraction. 相似文献
104.
105.
Effect of estrogen plus progestin on global cognitive function in postmenopausal women: the Women's Health Initiative Memory Study: a randomized controlled trial 总被引:23,自引:2,他引:21
Rapp SR Espeland MA Shumaker SA Henderson VW Brunner RL Manson JE Gass ML Stefanick ML Lane DS Hays J Johnson KC Coker LH Dailey M Bowen D;WHIMS Investigators 《JAMA》2003,289(20):2663-2672
Context Observational studies have suggested that postmenopausal hormone treatment may improve cognitive function, but data from randomized clinical trials have been sparse and inconclusive. The Women's Health Initiative Memory Study (WHIMS) is an ancillary study of the Women's Health Initiative (WHI) hormone therapy trials. On July 8, 2002, the estrogen plus progestin therapy in the WHI trial was discontinued because of certain increased health risks for women. Objective To determine whether estrogen plus progestin therapy protects global cognitive function in older postmenopausal women. Design, Setting, and Participants A randomized, double-blind, placebo-controlled clinical trial, WHIMS is an ancillary study of geographically diverse, community-dwelling women aged 65 years or older from 39 of 40 clinical centers within the WHI estrogen plus progestin trial that started in June 1995. Of 4894 eligible postmenopausal women aged 65 years or older and free of probable dementia at baseline, 4532 (92.6%) were enrolled in the estrogen plus progestin component of WHIMS. A total of 4381 participants (96.7%) provided at least 1 valid cognitive function score between June 1995 and July 8, 2002. Interventions Participants received either 1 daily tablet containing 0.625 mg of conjugated equine estrogen with 2.5 mg of medroxyprogesterone acetate (n = 2145) or matching placebo (n = 2236). Main Outcome Measure Global cognitive function measured annually with the Modified Mini-Mental State Examination. Results The Modified Mini-Mental State Examination mean total scores in both groups increased slightly over time (mean follow-up of 4.2 years). Women in the estrogen plus progestin group had smaller average increases in total scores compared with women receiving placebo (P = .03), but these differences were not clinically important. Removing women by censoring them after adjudicated dementia, mild cognitive impairment, or stroke, and nonadherence to study protocol, did not alter the findings. Prior hormone therapy use and duration of prior use did not affect the interpretation of the results, nor did timing of prior hormone therapy initiation with respect to the final menstrual period. More women in the estrogen plus progestin group had a substantial and clinically important decline (2 SDs) in Modified Mini-Mental State Examination total score (6.7%) compared with the placebo group (4.8%) (P = .008). Conclusions Among postmenopausal women aged 65 years or older, estrogen plus progestin did not improve cognitive function when compared with placebo. While most women receiving estrogen plus progestin did not experience clinically relevant adverse effects on cognition compared with placebo, a small increased risk of clinically meaningful cognitive decline occurred in the estrogen plus progestin group. 相似文献
106.
107.
Cefalu WT; Wagner JD; Bell-Farrow AD; Edwards IJ; Terry JG; Weindruch R; Kemnitz JW 《Toxicological sciences》1999,52(2):49-55
Caloric restriction (CR) has been observed to retard aging processes and
extend the maximum life span in rodents. In an effort to evaluate the
effect of this nutritional intervention on physiologic variables in higher
species, several nonhuman primate trials are ongoing. In particular, a
study evaluating the independent effect of CR on the extent of
atherosclerosis was initiated in 1993 in 32 adult cynomolgus monkeys.
Therefore, the trial was designed to achieve identical cholesterol intake
after animals were randomized to a control group or a calorie-restricted
group (30% reduction from baseline caloric intake). The animals were
routinely evaluated for glycated proteins, plasma insulin and glucose
levels, insulin sensitivity, and specific measures for abdominal fat
distribution by CT scans over a 4-year interval. The results from 4 years
of intervention demonstrate that CR improves cardiovascular risk factors
(such as visceral fat accumulation) and improves insulin sensitivity. In
contrast to other primate studies with normolipidemic animals, CR had no
independent effects on plasma lipid levels and composition in the presence
of equivalent amounts of dietary cholesterol intake. Preliminary analysis
of atherosclerotic lesion extent in the abdominal aorta has failed to
demonstrate differences between control animals and CR animals. Follow- up
studies are being conducted to determine the effect of CR on
atherosclerosis extent in coronary and carotid arteries.
相似文献
108.
109.
JV Leonard JW Seakins K Bartlett J Hyde J Wilson B Clayton 《Archives of disease in childhood》1981,56(1):53-59
The clinical course of 4 patients who had reduced activities of 3-methylcrotonyl CoA carboxylase (also called 3-methylcrotonylglycinuria) is described. Two children presented with a metabolic acidosis, one in the neonatal period and the other with episodes of acidosis that started in the second year of life. In the other 2 children neurological symptoms were prominent, one having infantile spasms and the other developmental regression with a skin rash and alopecia. Three of the children responded well to oral biotin and dietary protein restriction but the fourth, despite a biochemical response to biotin, has a severe neurological handicap. The clinical presentation of inborn errors of 3-methylcrotonyl CoA carboxylase is variable. Metabolic acidosis may not be conspicuous and instead neurological features may predominate. 相似文献
110.
The distinction between true and suspected poisoning in children has not been made clear in previous work on childhood poisoning. A study of suspected poisoning in children under 15 years of age in a defined population of North East Bristol from November 1970 to July 1973 carried out by the Health Education Council Medical Research Division included 53,000 child-years at risk. The number of suspected poisonings was 3-4/1000 population aged under 15 years per year, with a higher incidence in younger age groups. Detailed investigation of the circumstances of the accidents carried out by a multidisciplinary team showed that at least 65%, and possibly as many as 78% were poisoning scares and not true poisoning. The evidence used by the casualty doctor and by the parents to diagnose poisoning was explored, and in many cases was circumstantial. Children with fathers in nonmanual occupations were over-represented. This may reflect differences in patterns of utilization behaviour rather than true differences in incidence. 相似文献