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41.
V af Geijersstam C Eklund Z Wang M Sapp JT Schiller J Dillner L Dillner 《Canadian Metallurgical Quarterly》1999,80(4):489-493
The importance and natural history of HPV infections in childhood is incompletely understood. We performed a survey for presence of serum antibodies to HPV capsids among 1031 children aged 0 to 13 years, resident in Stockholm, Sweden. The HPV seroprevalence among these children was 3.0% for HPV16, 0.6% for HPV18 and 2.7% for HPV33. By comparison, among simultaneously analyzed positive control panels comprising women with CIN or healthy women with type-specific cervical HPV DNA, seroprevalence of HPV 16, 18 and 33 was 69%, 58% and 63% respectively. The results suggest that HPV infection in childhood is not common. 相似文献
42.
Fluoride's role in decreasing dental caries has been recognized for decades. The professional fluoride treatment has recently been augmented with home-use fluoride products. The introduction of many attractive products makes it difficult for dental professionals to know which are effective. Both professional and home-use products are described, as are proven techniques for their use. Recognition of fluoride toxicity, and its prevention and treatment, are also discussed. 相似文献
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CK Sites MD Tischler JA Blackman J Niggel JT Fairbank M O''Connell T Ashikaga 《Canadian Metallurgical Quarterly》1999,71(1):137-143
This study examined the effects of neonatal cocaine exposure on the rewarding properties of play in a modified T-maze. Animals were artificially reared from postnatal day (PND) 4-9 with drug concentrated in four daily feeds. There were four treatment groups, 40 mg/kg/day cocaine, 20 mg/kg/day cocaine, an artificially reared control and a surgery control. From PND 38-42, subjects were tested with a food reward (EXP 1) or a play reward (EXP 2). No deficits in learning were seen when the reward was food. The 20 mg/kg/day cocaine group, however, showed impaired learning and altered play behavior when the reward was access to a play partner. Neonatal cocaine exposure thus appears to differentially affect learning based on the type of reward presented. 相似文献
46.
JT Barr KB Schechtman BA Fink GE Pierce CD Pensyl K Zadnik MO Gordon 《Canadian Metallurgical Quarterly》1999,18(1):34-46
Fibroblast growth factor-16 (FGF-16) is the most recent member of the FGF family to be cloned. Since the biologic activity of rat FGF-16 (rFGF-16) was unknown, and this protein has no apparent signal sequence, we transformed its entire cDNA into Escherichia coli for high-level expression and further characterization of this novel protein. An attempt was made to purify the expressed protein from the supernatant of mechanically lysed cells using sequential cation-exchange chromatography. This resulted in a gradual loss of the protein as precipitate throughout the purification process. In addition to precipitation during purification, sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the partially purified materials showed a cluster of protein bands around 20k to 29k. Sequence analysis of the major bands indicated that two N-terminal truncations had occurred, during E. coli fermentation, purification, or both. The largest truncation resulted in the removal of the 34 N-terminal amino acids, including the initiation codon methionine. We cloned d34 rFGF-16, expressed the gene in E. coli, and developed a purification process for this form. Even with this truncated form, precipitation was a problem. We were largely able to overcome this problem, however, by including EDTA throughout the purification process. We have characterized the structure of purified d34 rFGF-16 extensively using circular dichroism, Fourier transform infrared spectroscopy, and sedimentation velocity analysis. These studies revealed that the protein has a distinct tertiary structure, consists primarily of beta-strands, has a weak tendency to self-associate, and is fairly extended. We then performed biologic assays which showed that d34 rFGF-16 induces oligodendrocyte proliferation in vitro, and induces hepatocellular proliferation and increased liver weight in vivo. In summary, FGF-16, a novel FGF family member, has both unique structural and biological properties. 相似文献
47.
Camilo García Diego Villagra Francesco Caruso Miriam Rossi Betty Matsuhiro Leonora Mendoza María J. Aguirre Mauricio Isaacs 《Inorganic chemistry communications》2009,12(5):392-395
The complex [FeII(Imz-phen)3](PF6)2, (Imz-phen = imidazolidine-[4,5-f]-1,10-phenanthroline) has been prepared and characterized using X-ray diffraction, UV–vis and IR spectroscopy, elemental analysis, fast atomic bombardment (FAB) mass spectrometry, and cyclic voltammetry. Its crystal lattice includes acetonitrile (π–π bound to phenanthroline), methanol, and water molecules. Scanning continuously between 1000 mV and 1650 mV in CH3CN, a modified electrode that includes the iron (II) complex is obtained; after the 25th continuous cycle a stable film is formed that is electrocatalytically active in the reduction of sulfur oxoanions. When the electrocatalytic properties are evaluated in ethanol/water solution, the current achieved from the electroreduction of these sulfur species is linearly dependent on the respective concentrations, suggesting potential application in sulfite determination. 相似文献
48.
Osteopetrosis or Albers-Schonberg disease is a rare hereditary disorder of osteoclast function in which resorption of bone is diminished, resulting in abnormally dense bones. The condition is known to occur in at least four recognizable clinical patterns, each of which is variable. The optimal treatment of fractures and of bone deformity in these patients has not previously been made clear. To determine appropriate orthopedic management of the condition, we conducted a survey of the membership of the Pediatric Orthopedic Society of North America. The combined experience of 57 surgeons who treated 79 patients with osteopetrosis was compiled. Four femoral neck fractures treated by closed reduction and internal fixation had a satisfactory result, but three treated nonoperatively developed varus and required osteotomy. A total of 20 hips was treated for coxa vara by various means, none of which was free of complications. Valgus osteotomy, when used as the primary treatment for coxa vara, was the most consistently satisfactory procedure, whereas in situ pinning failed in two of three hips. Fourteen subtrochanteric fractures and 31 other fractures of the femur were treated. Good results were reported with traction or casting or both in the majority of those fractures. Twenty-nine tibia fractures were treated successfully, the majority by nonoperative means. Upper extremity fractures healed well with closed reduction and casting. Vertebral fractures, spondylolysis, and back pain were most frequently treated without surgery. 相似文献
49.
Retrospective analysis of the Beijing family of Mycobacterium tuberculosis in preserved lung tissues
L Qian JD Van Embden AG Van Der Zanden EF Weltevreden H Duanmu JT Douglas 《Canadian Metallurgical Quarterly》1999,37(2):471-474
Direct repeat spoligotyping of 85 paraffin-embedded lung biopsies was used to investigated the occurrence around Beijing of the Beijing family of Mycobacterium tuberculosis. Samples ranged in time from 1956 to 1990. Hybridization patterns were found with 49 (58%) samples, and 45 (92%) produced typical Beijing family patterns extending over the 34-year period. 相似文献
50.
BK Ganser S Li VY Klishko JT Finch WI Sundquist 《Canadian Metallurgical Quarterly》1999,283(5398):80-83
The genome of the human immunodeficiency virus (HIV) is packaged within an unusual conical core particle located at the center of the infectious virion. The core is composed of a complex of the NC (nucleocapsid) protein and genomic RNA, surrounded by a shell of the CA (capsid) protein. A method was developed for assembling cones in vitro using pure recombinant HIV-1 CA-NC fusion proteins and RNA templates. These synthetic cores are capped at both ends and appear similar in size and morphology to authentic viral cores. It is proposed that both viral and synthetic cores are organized on conical hexagonal lattices, which by Euler's theorem requires quantization of their cone angles. Electron microscopic analyses revealed that the cone angles of synthetic cores were indeed quantized into the five allowed angles. The viral core and most synthetic cones exhibited cone angles of approximately 19 degrees (the narrowest of the allowed angles). These observations suggest that the core of HIV is organized on the principles of a fullerene cone, in analogy to structures recently observed for elemental carbon. 相似文献