几种抗炎药对白三烯B_4生物合成的影响

白三烯B_4为花生四烯酸5-脂氧酶代谢产物,是炎症反应中的重要介质。目前抑制白三烯B_4生物合成的药物尚不多见。本文建立了测定白细胞来源白三烯B_4的反相高效液相色谱法,并初步探讨了几种抗炎药对白三烯B_4生物合成的影响。结果表明阿斯匹林、消炎痛、炎痛喜康、氢化可的松及麝香第一色带对白三烯B_4生物合成几无影响,而氟灭酸可明显抑制白三烯B_4生成,提示它可能是5-脂氧酶抑制剂。     

Tutoring in a problem-based curriculum: expert versus nonexpert

Many studies have examined whether being an "expert" influences the success of a tutor in a problem-based learning curriculum. There are, however, no established standards by which to determine expertise. The purpose of this study was to examine whether students evaluate expert and nonexpert tutors comparably and to determine whether setting different standards to determine expertise influences the outcome of the above findings. Tutor evaluations, consisting of eight Likert-type questions completed by first-, second-, and third-year dental students, were analyzed. Tutors were ranked by the authorswithin three different categories of expertise based on the highest educational degree they had attained, familiarity with the specific subject matter, and previous problem-based learning (PBL) experience. Linear regression analyses were then performed between each category and student evaluation results. A statistically significant difference was found in the way students evaluated experts, but only when expertise was defined by the tutor's previous tutorial experience. The findings of this study underscore the importance of the retention of dental faculty with PBL experience in a PBL-based curriculum.     

Hospital emergency department visits attributed to pulpal and periapical disease in the United States in 2006

Background

Relatively localized conditions such as infection of the pulp or periapical tissues if left untreated could spread and require hospital care. The objectives of this study were to assess the prevalence of such hospital-based emergency department (ED) visits, to quantify hospital charges associated with those visits, and to identify characteristics of those members of the population who are likely to make such visits.

Methods

The experimental design of this study involves the use of The Nationwide Emergency Department Sample for the year 2006. All discharges with a primary diagnosis code for pulpal and periapical diseases (International Classification of Disease, Clinical Modification [ICD-9-CM] code of 522) were selected for analysis. All estimates were projected to national levels using the discharge weight variables.

Results

In the United States, during the year 2006, a total of 403,149 ED visits had a primary diagnosis code for pulp and periapical diseases. The average patient age was 32.9 years. The mean hospital charge for ED visits was $480, and the total charges for all the ED visits in the United States was $163,692,957. Among the ED visits, 5,721 were admitted to the same hospital for inpatient care. The mean length of stay after hospitalization was 2.95 days. The uninsured (39.92%) constituted the largest proportion of all ED visits.

Conclusions

This study identifies high-risk groups that are likely to present to hospital-based EDs for the treatment of pulp and periapical diseases. This highlights the need for significant resources to treat such patients in a hospital care setting.     

Relationship between dental students' performance on standardized multiple-choice examinations and OSCEs

The purpose of this study was to examine the relationship among dental students' performance on the National Board Dental Examination (NBDE Parts I and II), comprehensive written multiple-choice question examinations (MCQ examinations), and objective structured clinical examinations (OSCEs) administered at the Harvard School of Dental Medicine (HSDM). Outcomes were measured during the third and fourth years at HSDM for the classes of 2006 and 2007. Three separate OSCE exams and two comprehensive MCQ examinations are administered during years 3 and 4 at HSDM per class. The study group was made up of sixty-two students (thirty-two females and thirty males). The average NBDE Parts I and II scores of the study population were 93.32 +/-4.02 and 84.63 +/-4.25, respectively, and were associated with outcomes on all three OSCE examinations (p相似文献   

Expression and functionality of the trkA proto-oncogene product/NGF receptor in undifferentiated hematopoietic cells

The expression of the low-affinity NGF receptor (p75) and the trkA proto-oncogene product was analyzed in a series of human hematopoietic cell lines at protein and RNA levels. We did not detect any form of NGF receptor in cell lines displaying a myelomonocytic phenotype (HL60 and U937). In contrast, cells displaying a more immature erythroleukemic phenotype (TF1 and K562) expressed TrkA in the absence of detectable p75. Scatchard analysis showed a single high-affinity site for NGF (kd = 10(-10) mol/L), with a copy number ranging from 300 to 3,000 sites per cell depending on the studied cell line. In addition, NGF induced autophosphorylation of TrkA and could substitute for granulocyte- monocyte colony-stimulating factor to trigger the proliferation of the TF1 cell line, with a half-maximal signal observed at 50 pmol/L, indicating that p75 is not required for DNA synthesis in this cell line. The physiologic relevance of NGF in early hematopoiesis was confirmed by showing that 12% to 15% of progenitor blood cells from mice treated with 5-fluorouracil expressed TrkA and that these cells could be induced to proliferate and differentiate in response to NGF in association with macrophage colony-stimulating factor. Our study demonstrates for the first time that trkA proto-oncogene expression and activation is not restricted to the nervous system, but is also an important element in early hematopoiesis.     

天然有机化合物质谱研究——Ⅺ.苯丙型苷快原子轰击质谱MNa+的MIKES谱

研究了六种苯丙型苷与Na⁺加合离子的快原子轰击质谱(FAB—MS)和质量分离离子动能谱(MIKES)。结果表明:在FAB谱中[M+Na]⁺加合离子的丰度要比[M+H]⁺离子高得多。由此可给出糖苷的分子量信息,[M+Na]⁺离子的MIKES谱可给出糖基序列信息。     

Hyperlipidaemia in renal transplantation—risk factor for long-term graft outcome

Abstract. The role of hyperlipidaemia for the outcome of renal transplantation was evaluated in a prospective study involving 151 patients. Graft losses were associated with more pronounced pre-transplant lipid abnormalities. An increased risk of graft loss during the first two post-transplant years was found in patients with marked pre-transplant hypercholestero-laemia (≥6.9 mmol L^-1, P = 0.014; relative risk 2.2). Hypercholesterolaemia ≥6.9mmol L^-1 at 6 months after transplantation, present in 41/115 patients, was associated with a lower GFR ( P = 0.007) and more pronounced albuminuria ( P = 0.009) at 2 years. In patients with graft dysfunction (serum creatinine >160μmol L^-1) at 2 years, more pronounced lipid abnormalities before and at 6 months after transplantation were found. Between 6 months and 2 years, total and LDL cholesterol did not change significantly, but HDL cholesterol decreased ( P = 0.03). In conclusion, hyperlipidaemia is also a risk factor for the long-term outcome in renal transplantation. Further investigations are needed to determine whether graft losses and late graft failure can be prevented or ameliorated by treating hyperlipidaemia in renal transplantation.     

几种抗炎药对白三烯B4生物合成的影响

白三烯B₄为花生四烯酸5-脂氧酶代谢产物,是炎症反应中的重要介质。目前抑制白三烯B₄生物合成的药物尚不多见。本文建立了测定白细胞来源白三烯B₄的反相高效液相色谱法,并初步探讨了几种抗炎药对白三烯B₄生物合成的影响。结果表明阿斯匹林、消炎痛、炎痛喜康、氢化可的松及麝香第一色带对白三烯B₄生物合成几无影响,而氟灭酸可明显抑制白三烯B₄生成,提示它可能是5-脂氧酶抑制剂。     

GC/FTIR联用分析麝香风湿油

本文用气相色谱/富里叶变换红外光谱联用对中成药麝香风湿油作了分析研究,鉴定了其中的十个主要组分。并对其中三个组分用气相色谱内标法做了含量测定。平均回收率为100±1.0%,变异系数<2.0%。     

Learning disabilities in dental education: trends,management, and concerns in U.S. dental schools

The prevalence of learning disabilities (LD) in higher education has drawn significant attention at the undergraduate level. College freshmen reporting learning disabilities have increased significantly in the past twenty years. Although anecdotal evidence suggests an increase in the number of dental students with learning disabilities, nothing has been published regarding how dental education is affected by this general trend. The purpose of this study was to obtain information from U.S. dental school administrators regarding the incidence and prevalence of learning disabilities in dental education. We hypothesized that there has been an increase in diagnosed cases of learning disabilities in dental education. Following a pilot study to identify individuals responsible for working with students with learning disabilities in U.S. dental schools (response rate 91 percent, n = 49), a eighteen-item survey instrument was distributed to specific contact individuals (response rate 81 percent, n = 44). Mean cumulative incidence of diagnosed cases of learning disabilities was 0.3 percent; mean prevalence of identified diagnosed cases of LD 0.7 percent. Pearson analysis revealed a statistically significant weak positive correlation between mean prevalence and year, suggesting an increase in identified diagnosed cases of LD in U.S. dental schools over the past seven years (r = 0.24, p = 0.002). We conclude that the presence of learning disabilities in dental education is silent, pervasive, and deserves increased attention.