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991.
Two laboratories exchanged and rescreened a large sample of cases with cervicovaginal smears they had consecutively accessioned to examine the reproducibility of gynecologic cytodiagnosis under optimum conditions. At least a "working agreement" (diagnoses within +/- 1 category on a ten-category scale) was achieved in diagnoses of normal, benign reaction and squamous abnormality (from minimal dysplasia though invasive cancer) in 18,859 cases (96.8%), of endometrial abnormality in 21 cases (42%) and of "unsatisfactory" in 99 cases (20.7%). Larger differences occurred in greater than or equal to 30% of cases except in the categories of "normal" and "benign reaction," reaching a maximum of 82% for moderate dysplasia. Reexamining 382 cases decreased disagreement by category to the 20% to 65% range only in the five categories of dysplasia plus carcinoma in situ. Agreement was not predicated on the presence of endocervical cells or squamous metaplasia; the basis for "unsatisfactory" calls was not uniform. Comparison of the laboratories' diagnoses with referee diagnoses or, on 178 cases, with tissue diagnoses also demonstrated differences in diagnostic criteria.  相似文献   
992.
Plasma lipid and lipoprotein concentrations from 3,074 nuclear families in the multiethnic Jerusalem Lipid Research Clinic study population were analyzed for possible involvement of major genes in determination of high levels of these traits. Complex segregation analysis under a mixed model including major gene and multifactorial transmissible components was performed on transformed-plasma lipids and lipoproteins after covariance adjustment for age, sex and environmental measures. Likelihood analysis provided evidence for recessive major genes influencing plasma triglyceride, and low-density lipoprotein cholesterol (LDL-C). The estimated gene frequencies for triglyceride and for hyperbetalipoproteinemia in our study population were about 0.1. Our positive results for total cholesterol and high-density lipoprotein cholesterol (HDL-C) were nonconclusive and the major effects could result from causes other than major genes. The mixed-model parameters were homogeneous across origin groups for LDL-C and HDL-C and heterogeneous for total plasma cholesterol and triglyceride. The multifactorial-transmission heritability index was similar in all origin groups for all the traits. The origin heterogeneity in the major gene parameters appeared to be mainly due to the North African group which favored a multifactorial transmission for all traits except for LDL-C.  相似文献   
993.
The presence of endometrial cells in cervical smears was studied in a large series of women participating in a population screening program for cervical cancer, in relation to different time periods of the menstrual cycle and to the method of contraception practiced. In the total group of women studied, endometrial cells were present in an average of 12% of the cervical smears. In women who were menstruating cyclically, the percentage of cervical smears containing endometrial cells was not age dependent. Only in women over 52 years was a lower number of endometrium-positive cervical smears found: in postmenopausal women, 0.6% of smears were found to contain endometrial cells. In menstruating women, the frequency of endometrial cells in cervical smears was highest during the menses. After day four, through the proliferative phase, the percentages of cervical smears containing endometrial cells markedly decreased. During the secretory phase, an average of 2% of the smears contained endometrial cells; in the premenstrual phase (after day 25), the percentages of endometrial cell-positive smears rose again. When related to the method of contraception practiced, significant differences in the percentages of cervical smears with endometrial cells appeared. In women using oral hormonal contraceptives, the average numbers of smears containing endometrial cells for the whole cycle as well as for each period of the cycle were significantly lower. This phenomenon might be due to endometrial atrophy on the basis of prolonged use of oral hormonal contraceptives. In women wearing an intrauterine device, at any moment the frequencies of smears with endometrial cells present were significantly higher than the values found in women using any other method of contraception or not using contraceptives. The evaluation of cells originating from the endometrium requires considerable experience. The identification of endometrial cells can be made with greater confidence when the cytologist is aware of the exact date of the menstrual cycle and of the impact on the presence of endometrial cells in cervical smears caused by different methods of contraception.  相似文献   
994.
Diastereomers of the title compound were obtained and absolute configuration was assigned by means of stereochemical correlation. Their reaction with 3'-O-methoxyacetylthymidine in the presence of triisopropylbenzenesulphonyl (4-nitro) triazole is neither chemo- nor stereo-selective and leads to diastereomeric pairs of dithymidyl (3',5')methanephosphonate and -methanephosphonothioate. Obtained results are discussed in terms of mechanism of activation of phosphodiesters under conditions known as "phosphotriester approach to oligonucleotide synthesis".  相似文献   
995.
The adrenergic and cholinergic innervation of the epididymal duct in the mouse has been investigated using histochemical methods and electron microscopy. This study demonstrates that the epididymal innervation of the mouse does not really differ from that of other mammals. Cholinergic nerves are mainly vascular, even in the cauda where cholinesterase activity is increased within the tubular musculature. Catecholamine fibres ensure the motricity of the wall of the canalicular system, particularly the terminal segment where the smooth muscle fibres are specifically differentiated.  相似文献   
996.
The development of the bovine ileal mucosa was studied with particular reference to maturation during the fetal and neonatal period. In this region, by 4-5 months of fetal development, vacuolation of the epithelial cells had occurred on the villi, and the goblet and absorptive cells in the crypts were present. By 6-9 months, the villi were longer and more numerous than in the previous stages. At the same time, the vacuolated cells could be seen predominantly on the upper half of each villus. The absorptive cells and goblet cells were more distinct in the crypt and lower half of each villus. Moreover, the goblet cells showed differences in mucin, while in the submucosa the lymphoid follicles were seen to have enlarged to become a prominent feature of the Peyer's patches at this stage. At birth, in suckled animals, the ileal cells on the lower area of each villus and in the crypt appeared more like mature cells. In contrast, there were numerous inclusion bodies in epithelial cells on the upper half of each villus. They appeared in the apical portion of the cytoplasm as vacuoles with stainable or dense contents. By 1 week, however, epithelial cells no longer contained inclusion bodies, and absorptive and goblet cell populations had begun to emerge from the crypts. These histological results suggest that the bovine ileal mucosa has two distinct turning points during its development in the fetus and the neonate. Initially all the mucosal structures are present in fetuses at 6-7 months of gestation, and then the vacuolated cells covering the ileal villi are replaced by mature, nonpinocytosing epithelium which emerges from the crypts on or before the 7th day after birth (ileal closure).  相似文献   
997.
Y Hayashi 《Acta anatomica》1987,129(4):279-288
Cementum crystals and matrix vesicles on the root surface of partially formed teeth in dogs were examined with a transmission electron microscope. Fine filamentous crystals were observed in the cementum calcifying fronts. The running pattern was mainly parallel to the root surface in the apical region and perpendicular to the root surface in lateral and coronal regions. Matrix vesicles were observed at the apical half of the periodontium, but not observed at the coronal region. These findings suggest that the parallel-arranged cementum would become the light-microscopic lamellar type and the perpendicular one the light-microscopic dense-line structure when fully developed. Moreover, cementum formation occurs due to two kinds of mechanisms: participation of matrix vesicles and secondary calcification (= additional cementogenesis).  相似文献   
998.
A simplified procedure for the isolation and purification of 124-kDa phytochrome from etiolated Avena seedlings has been developed using the method of ammonium sulfate back-extraction. After hydroxyapatite chromatography of seedling tissue extracts, the pooled phytochrome was subjected to ammonium sulfate back-extraction instead of the usual application to an Affi-Gel Blue column. The resulting phytochrome had specific absorbance ratios (SAR = A666/A280) ranging from 0.85 to 0.95. Subsequent Bio-Gel filtration chromatography yielded highly pure 124-kDa phytochrome with SAR values ranging from 0.99 to 1.13. The absorption maxima of 124-kDa phytochrome were at 280, 379, and 666 nm for the red absorbing form of phytochrome (Pr) and at 280, 400 and 730 nm for the far-red absorbing form (Pfr). The A730/A673 ratio in Pfr was found to be 1.5 to 1.6. The mole fraction of Pfr under red light photoequilibrium was 0.88. No dark reversion was detected within 5 h at 3 degrees C. A photoreversible far-uv-circular dichroism was observable with all phytochrome preparations examined. Fluorescence and phosphorescence lifetimes were measured to further characterize the differences between the phytochromes prepared under different conditions. The Trp fluorescence and phosphorescence lifetimes of Pr and Pfr with the chromophore "X", probably polyphenolic in nature, were significantly shorter than those of phytochrome without the contaminant X. The short lifetime of the fluorescence of the Pr chromophore is attributable to X in the former.  相似文献   
999.
Wilms tumor, a common childhood renal tumor, occurs in both a heritable and a nonheritable form. The heritable form may occasionally be attributed to a chromosome deletion at 11p13, and tumors from patients with normal constitutional chromosomes often show deletion or rearrangement of 11p13. It has been suggested that a germinal or somatic mutation may occur on one chromosome 11 and predispose to Wilms tumor and that a subsequent somatic genetic event on the normal homologue at 11p13 may permit tumor development. To study the frequency and mechanism of such tumor-specific genetic events, we have examined the karyotype and chromosome 11 genotype of normal and tumor tissues from 13 childhood renal tumor patients with different histologic tumor types and associated clinical conditions. Tumors of eight of the 12 Wilms tumor patients, including all viable tumors examined directly, show molecular evidence of loss of 11p DNA sequences by somatic recombination (four cases), chromosome loss (two cases), and recombination (two cases) or chromosome loss and duplication. One malignant rhabdoid tumor in a patient heterozygous for multiple 11p markers did not show any tumor-specific 11p alteration. These findings confirm the critical role of 11p sequences in Wilms tumor development and reveal that mitotic recombination may be the most frequent mechanism by which tumors develop.  相似文献   
1000.
Conventional fractionation methods are time consuming, thus they prolong the time required to process low-stability restriction enzymes. We now report a rapid and effective two-step chromatographic method that affords high purity endonucleases in a short time. Accordingly, an inexpensive chromatographic adsorbent such as phosphocellulose or dyed agarose in the first step is coupled to a high-performance ion exchanger, namely, MonoQ, in the second step. The purification schemes reported here are now in routine use to prepare high-purity BanII, SacI, and SphI as judged by the "overdigestion" and "cut-ligate-recut" stringent quality tests.  相似文献   
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