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991.
Human dental pulp cells were cultured in fluoridated mediums (0, 1, 10, 25 ppm) in order to study the biological effect of the ion regarding the cellular metabolism: cell growth, alkaline phosphatase (ALP) activity, and protein synthesis. The results indicated a decrease of the cell growth at 25 ppm and a dose-dependent decrease of the ALP activity. Type I collagen immunoperoxidase staining, radioimmunoassay quantitation, and analysis of type I and III collagens mRNA levels showed an inhibition of collagen production and gene expression. In contrast, fibronectin production and gene expression were not affected by fluoride. The treatment did not influence the qualitative pattern of the different mRNA species. Of the three collagen chains, the alpha 1(I) was the most affected. These data suggest that fluoride does not exert a general depletive effect on human dental pulp cells but rather a selective inhibition on collagen production. 相似文献
992.
L Riles JE Dutchik A Baktha BK McCauley EC Thayer MP Leckie VV Braden JE Depke MV Olson 《Canadian Metallurgical Quarterly》1993,134(1):81-150
Physical maps of the six smallest chromosomes of Saccharomyces cerevisiae are presented. In order of increasing size, they are chromosomes I, VI, III, IX, V and VIII, comprising 2.49 megabase pairs of DNA. The maps are based on the analysis of an overlapping set of lambda and cosmid clones. Overlaps between adjacent clones were recognized by shared restriction fragments produced by the combined action of EcoRI and HindIII. The average spacing between mapped cleavage sites is 2.6 kb. Five of the six chromosomes were mapped from end to end without discontinuities; a single internal gap remains in the map of chromosome IX. The reported maps span an estimated 97% of the DNA on the six chromosomes; nearly all the missing segments are telomeric. The maps are fully cross-correlated with the previously published SfiI/NotI map of the yeast genome by A. J. Link and M. V. Olson. They have also been cross-correlated with the yeast genetic map at 51 loci. 相似文献
993.
A computer simulation method is suggested which uses the microwave negative resistance distribution profile within the depletion layer of an ATT device to calculate the phase distortion due to tunnel injected current. The method has been applied to explain the deterioration of device performance in GaAs/GaInAs heterostructure IMPATTs for high frequency operation.<> 相似文献
994.
995.
Endemic skeletal fluorosis is characterized by bone, joint and muscle pain, progressive ankylosis of various joints and crippling deformities. Whole body skeletal scintigraphy with 99Tcm-methylene diphosphonate was performed for 17 symptomatic subjects suffering from this disorder. The fluoride content of drinking water ranged from 4.1 to 12.9 mg l-1 (normal < 1 mg l-1). Urinary and serum fluoride levels were markedly elevated. Serum calcium (total and ionized), inorganic phosphorus, creatinine and albumin were essentially normal while serum alkaline phosphatase was elevated in six subjects (mean +/- S.D. 206 +/- 106; range 22-1072 IU l-1). Skeletal radiology revealed a wide spectrum of bony abnormalities. Skeletal scintigraphy revealed a picture similar to metabolic 'superscan' in all subjects, i.e. increased tracer uptake in axial and appendicular skeleton, reduced soft tissue uptake, poor or absent renal images, prominent costochondral junction and 'tie' sign in sternum. Increased uptake was present in all subjects irrespective of age, water fluoride content, serum alkaline phosphatase level and radiological abnormalities. Our findings suggest the presence of a high bone turnover state in endemic skeletal fluorosis irrespective of other variables. 相似文献
996.
Many nurse scientists consider caring to be the core concept of nursing practice. This article describes the caring process that occurs when a nurse and a client interact in a nursing care situation. This interactional process has five integrating phases: co-presence, experience-sharing, caring acts, caring-perception, and mutual care-receiving. The authors provide a specific example that illustrates this caring process. The difficulties inherent in the caring process relate to one, or a combination of, three factors: the nurse, the client, and/or the circumstances. Nurses must be cognizant of the client's expression of subtle clues that indicate the need for caring. They also need to learn to recognize their own personal signals that might prevent them from engaging in the caring process. For caring, in its full context, can only occur when nurses know how to care for themselves. Nurses face unpredictability and challenges in their practice on a daily basis. In order to promote caring they must learn to promote an environment that nurtures this process. The authors discuss the essential characteristics of a favorable caring environment and present the conditions that can enhance quality nursing. The challenges that caring nurses face are counterbalanced by the value they attribute to this basic human need and the profound human benefits that caring brings. 相似文献
997.
TH Strong MW Howard BK Wade CS Miura JP Elliott 《Canadian Metallurgical Quarterly》1993,38(5):397-399
Amnioinfusion is an intrapartum technique that is not usually attempted in twin gestations. This report describes infusion of normal saline into the amniotic sacs of three twin gestations with oligohydramnios. All the twins were safely delivered vaginally. No untoward effects were noted. Ultrasound is advised following amnioinfusion to assess the increase in the amniotic fluid volume. 相似文献
998.
999.
R Thun H Kündig K Zerobin H Kindahl BK Gustafsson W Ziegler 《Canadian Metallurgical Quarterly》1993,135(11-12):333-344
In the present study the effect of Flunixin meglumine (FM), a cyclooxygenase inhibitor, was investigated on postpartal prostaglandin production and uterine activity in the cow. For that purpose 8 cows were given FM in a dose of 2.2 mg/Kg b.w. twice daily (08.00 and 16.00 h) for the first 10 days p.p. Blood samples were collected at various times before, during and after parturition and the concentrations of 15-keto-13,14-dihydro-PGF2 alpha (PGFM), progesterone as well as adrenaline and noradrenaline determined. Eight cows served as controls. Uterine activity was measured by means of pressure microsensors and electrodes which were surgically implanted into the uterine wall before parturition. During the whole treatment period FM inhibited endogenous PG-production by more than 80% (p < 0.05). The suppressive effect of FM was maximal 4 h after the last injection and lasted no longer than 8 h. PGF2 alpha-suppression clearly decreased spontaneous uterine motility and reduced the myometrial response to ocytocin (5 IU i.v.) and PGF2 alpha (15 mg i.v.). Treatment with FM did not interfere with uterine involution, the return to cyclicity and the first postpartal cycle length. Also, no obvious effects were seen on catecholamine concentrations which fluctuated during parturition without regularly representing the actual stress situation. Our results demonstrate that FM is able to effectively inhibit PGF2 alpha-secretion as well as uterine activity in the cow. Further evaluation of FM as a tocolyticum or in the treatment of uterine infections is required. 相似文献
1000.