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991.
This report discusses the rationale for and implications of the implementation of a new population standard for the age standardization (age adjustment) of death rates. The new standard is based on the year 2000 population and beginning with data year 1999, will replace the existing standard based on the 1940 population. This report also includes a technical discussion of direct and indirect standardization and statistical variability in age-adjusted death rates. Currently, at least three different standards are used among Department of Health and Human Services agencies. Implementation of the year 2000 standard will reduce confusion among data users and the burden on State and local agencies. Use of the year 2000 standard will also result in age-adjusted death rates that are substantially larger than those based on the 1940 standard. Further, the new standard will affect trends in age-adjusted death rates for certain causes of death and will narrow race differentials in age-adjusted death rates. Although age standardization is an important and useful tool, it has some limitations. As a result the examination of age-adjusted death rates should be the beginning of an analysis strategy.  相似文献   
992.
BACKGROUND: Susceptibility to head and neck cancer in a particular individual may depend in part on the metabolic balance between Phase 1 enzymes, such as cytochromes P450 (CYPs), and Phase II enzymes, such as glutathione S-transferases (GSTs). Genetic variability in CYP and GST isoenzymes may contribute to individual differences in susceptibility to chemical carcinogenesis. GSTM1 and GSTT1 null genotypes as well as polymorphic variants in the CYP1A1 gene that may help determine the risk for head and neck cancer have been described in previous reports. METHODS: Polymorphisms of GSTM1, GSTT1, and CYP1A1 in whole blood were detected by polymerase chain reaction (PCR) in 185 patients with head and neck squamous cell carcinoma (HNSCC), 78 patients with benign head and neck lesions (BHNL), and 207 blood donors. RESULTS: GSTM1 null genotype was demonstrated to be equally frequent in patients with HNSCC (50.8%), patients with BHNL (47.4%), and blood donors (51.7%). GSTT1 null genotype occurred significantly more often in patients with BHNL (33.3%) as compared with blood donors (20.3%), demonstrating that lack of GSTT1 may be a risk factor for BHNL. Presence of the rare valine in the CYP1A1/Nco1 site was found in 33 patients with HNSCC (17.8%), in 20 patients with BHNL (25.6%), and in 34 blood donors (16.4%). The frequencies with which the presence of the rare cytosine nucleotide in the CYP1A1/Msp1 site was detected were 17.8%, 15.4%, and 15.9%, respectively. CONCLUSIONS: The occurrence of polymorphic variants in the GSTM1, GSTT1, and CYP1A1 genes did not differ between the groups investigated, therefore indicating no significant contribution to the development of head and neck cancer.  相似文献   
993.
The conformational changes of the active site of creatine kinase (ATP: creatine N-phosphotransferase EC 2.7.3.2.) during thermal denaturation was followed by changes in fluorescence at the active site of the enzyme labeled by o-phthalaldehyde. Conformational changes of the active site occurred at the same time as inactivation of the enzyme. The active site changes occurred before the denaturation of the enzyme molecule as a whole was detected. The above results showed that the thermal inactivation of the creatine kinase was due to the conformational changes of its active sites.  相似文献   
994.
This study examined the prevalence of consistent condom use among inner-city women at risk for HIV, measured the distribution of these women across the stages of change for condom use, determined psychosocial factors associated with the stages, and suggested intervention strategies based on the results. The 5-city sample of women aged 15-34 years consisted predominantly of African Americans. Only 18% reported consistent condom use with main partners and 45% with other partners. Logistic regressions compared women in each stage of change with those in higher stages for each partner type. Results indicated that women who practice or intend to practice consistent condom use were more likely to talk with others about condoms, acknowledge the advantages of condoms, have higher self-efficacy for condom use, and indicate that people important to them favored condom use. Intervention approaches are suggested for women in different stages of change for condom use.  相似文献   
995.
In patients presenting with diarrhoea and vitamin deficiency even years after gastro-intestinal surgery, the possibility of fistulas should be considered. Four patients with persistent diarrhoea years after gastric surgery are described. Diagnosis of cholecystocolic and gastrocolic fistulas were made by barium enema and resection of the fistulas was performed.  相似文献   
996.
997.
998.
Primary brain tumours are usually assessed by computed tomography (CT) and magnetic resonance imaging (MRI), sometimes in conjunction with positron emission tomography (PET). We used cobalt-55 (55Co) as a calcium (Ca) tracer to visualize decaying tumour tissue, based on the fact that Ca-influx is essential in both cell death and leukocyte activation. Net 55Co uptake may be the result of cell decay, leukocyte infiltration, (re)perfusion and the pharmacological profile of 55Co. Three patients with primary malignant brain tumours (first presentation) were studied with CT, MRI and Co-PET after the intravenous administration of 0.5 mCi 55Co. Histopathological diagnosis was obtained by biopsy or resection. Co-PET demonstrated each of the brain tumours and showed good topographical agreement with CT and MRI. Co-PET provided additional detail as to the site and size of the necrotic core and the perinecrotic rim of decaying tumour. The 55Co uptake indices varied between 2.6 and 5.3. 55Co demonstrated uptake in decaying tissue, irrespective of the integrity of the blood-brain barrier. Neither necrotic nor viable tumour tissue showed affinity for 55Co. Since 55Co is readily applicable to both PET and single photon emission tomography (SPET), differences in the uptake mechanism and functional significance of the 55Co tracer are discussed in relation to 201Tl SPET. We present a (limited) pilot series of three patients to forward the claim of this new functional technique in nuclear neurology.  相似文献   
999.
1000.
Ethanol has been reported to exacerbate psoriasis. Since immunological mechanisms are considered to be important for the pathogenesis of psoriasis, we compared the effects of ethanol on lymphocyte proliferation in 15 healthy control individuals and 15 patients with psoriasis. We employed the spontaneous and phytohemagglutin in (PHA)-induced uptake of 3H-TdR to measure lymphocyte proliferation. Ethanol was added to cultures at concentrations ranging from 0.5 to 0.0005% (vol./vol.). We found that both spontaneous and PHA-driven lymphocyte proliferations were significantly lower in patients with psoriasis (P < 0.002). Spontaneous blastogenesis in both controls and patients remained stable under ethanol. In controls, ethanol suppressed the PHA-driven lymphocyte proliferation in a dose-dependent fashion. By contrast, in patients with psoriasis ethanol significantly increased lymphocyte proliferation by 2-3 times (p < 0.002). Our data indicate that in psoriasis the lower lymphocyte transformation is abnormally enhanced by minimal doses of ethanol.  相似文献   
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