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RN Shain JM Piper ER Newton ST Perdue R Ramos JD Champion FA Guerra 《Canadian Metallurgical Quarterly》1999,340(2):93-100
Using annual bite-wing radiographs, the incidence and progression of approximal caries (4d-7m) were assessed longitudinally in teenagers and adolescents whose treatment had been based on remineralizing rather than restorative strategies. A closed cohort of 536 children initially was followed from 11 to 22 years of age. The scoring system was: 0 = no visible radiolucency; 1-2 = radiolucency in the enamel up to the enamel-dentin border; 3 = radiolucency with a broken enamel-dentin border but with no obvious progression in the dentin; 4 = radiolucency with obvious spread in the outer half of the dentin, and 5 = radiolucency in the inner half of the dentin. Caries rates were estimated as the number of new lesions/100 tooth surface-years, and the Kaplan-Meier estimate was used to calculate the cumulative survival time of each approximal surface. Three events were used: the transitions from states 0 to 2, 2 to 4 and 3 to 4. The results showed a considerable variation between the surfaces in both caries rates and survival time. For all surfaces combined, the median caries rate from state 0 to 2 was 3.9 new lesions/100 tooth surface-years; from state 2 to 4, the rate was 5.4, and from state 3 to 4 it was 20.3. Of the sound surfaces (state 0), 75% survived 6.3 years without reaching state 2. Given state 2, 75% survived 4.8 years without reaching the outer half of the dentin (state 4), while given a lesion at the enamel-dentin border (state 3), 75% survived 1.3 years without doing the same. The median survival time of lesions from state 3 to 4 was 3.1 years. The group with DMFSappr>1 at the age of 11-12 years had a risk of new approximal enamel lesions (state 0-2) that was 2.5 times greater than that of the group with DMFSappr = 0-1. 相似文献
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M LeBeau W Andollo WL Hearn R Baselt E Cone B Finkle D Fraser A Jenkins J Mayer A Negrusz A Poklis HC Walls L Raymon M Robertson J Saady 《Canadian Metallurgical Quarterly》1999,44(1):227-230
The recent increase in reports of drug-facilitated sexual assaults has caused alarm in the general public and prompted forensic toxicologists from across North America to address the toxicological issues surrounding this matter. The authors have developed recommendations and guidelines to inform law enforcement, medical, and scientific personnel of the requirements for performing successful toxicological examinations in cases of drug-facilitated rape. 相似文献
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Purification and crystallization of complexes modeling the active state of the fragile histidine triad protein 总被引:1,自引:0,他引:1
Brenner C; Pace HC; Garrison PN; Robinson AK; Rosler A; Liu XH; Blackburn GM; Croce CM; Huebner K; Barnes LD 《Protein engineering, design & selection : PEDS》1997,10(12):1461-1463
Fragile histidine triad protein (Fhit) is a diadenosine triphosphate
(ApppA) hydrolase encoded at the human chromosome 3 fragile site which is
frequently disrupted in tumors. Reintroduction of FHIT coding sequences to
cancer cell lines with FHIT deletions suppressed the ability of these cell
lines to form tumors in nude mice even when the reintroduced FHIT gene had
been mutated to allow ApppA binding but not hydrolysis. Because this
suggested that the tumor suppressor activity of Fhit protein depends on
substrate-dependent signaling rather than ApppA catabolism, we prepared two
crystalline forms of Fhit protein that are expected to model its
biologically active, substrate-bound state. Wild-type and the His96Asn
forms of Fhit were overexpressed in Escherichia coli, purified to
homogeneity and crystallized in the presence and absence of ApppA and an
ApppA analog. Single crystals obtained by vapor diffusion against ammonium
sulfate diffracted X-rays to beyond 2.75 A resolution. High quality native
synchrotron X-ray data were collected for an orthorhombic and a hexagonal
crystal form.
相似文献
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JF de Kroon RA de Paus HC Kluin-Nelemans PM Kluin CA van Bergen AJ Munro G Hale R Willemze JH Falkenburg 《Canadian Metallurgical Quarterly》1996,24(8):919-926
Severe combined immunodeficient (Scid) mice inoculated with the human (t(14;18)-positive B cell lines DoHH2 and BEVA develop lethal systemically disseminated lymphoma (de Kroon et al., Leukemia 8:1385, and Blood 80 [suppl 1]:436). These models were used to study the therapeutic effect of rat-anti-human CD52 (Campath-1G) or CD45 monoclonal antibodies (mAbs) on systemically disseminated tumor cells and on tumor cells present in solid tumor masses. Both mAbs were effective in inhibiting growth of systemically disseminated malignant cells. When treatment with anti-CD52 or anti-CD45 mAbs at a dose of 30 micrograms/mouse/d for 4 days was started 24 hours after intravenous inoculation of human DoHH2 or BEVA cells, a 3-log kill of tumor cells was observed as measured by prolonged survival. After treatment, surviving animals injected with high numbers of BEVA cells showed tumor masses in liver, kidney, and mesenteric lymph nodes. In contrast to nontreated animals, however, only low numbers of malignant cells were found in peripheral blood, and bone marrow was free of tumor cells. Similarly, after mAb treatment of mice inoculated subcutaneously (sc) with DoHH2 cells, no tumor cells could be found in the bone marrow, and few DoHH2 cells could be detected in the peripheral blood, spleen, liver, kidney, or lung. In contrast, tumor cells present in subcutaneous tumors and axillary lymph nodes were relatively unaffected by mAb therapy. The presence of rat immunoglobulin (Ig) could be demonstrated on surviving tumor cells. The presence of murine macrophages in areas in these tumors that were depleted of DoHH2 cells suggested that the mAb-mediated antitumor effect observed in the Scid mouse model is mediated by cellular mechanisms. Apparently these mechanisms were not sufficient to eliminate the fast-growing tumor cells present in the protected sites. Our results indicate that treatment with anti-CD52 or anti-CD45 mAbs potentially may be useful as adjuvant immunotherapy for systemically disseminated B cell lymphoma. 相似文献