Multivariate comparison of elemental concentrations in human teeth

R-mode factor analysis was applied to characterize the chemical composition of human teeth investigated by particle induced X-ray emission (PIXE), Rutherford backscattering spectrometry (RBS) and X-ray fluorescence (XRF) techniques. The approach developed in this study enabled the separation between essential mineral teeth components and the pollutants deposited in teeth tissues during the human life. The three independent sources of metals incorporated in human teeth were found. The first source, representing about 43% of the variance of the concentration data, was characterized by pollutant elements of power industry emissions. The second factor was loaded with toxic elements of general urban pollution. The third factor represented the tooth source as it contained mainly large fractions of the mineral components of the tooth tissue as Ca and K.     

Cross-cultural invariance of the Academic Expectations Stress Inventory: Adolescent samples from Canada and Singapore

We provide further evidence for the two-factor structure of the 9-item Academic Expectations Stress Inventory (AESI) using confirmatory factor analysis on a sample of 289 Canadian adolescents and 310 Singaporean adolescents. Examination of measurement invariance tests the assumption that the model underlying a set of scores is directly comparable across groups. This study also examined the cross-cultural validity of the AESI using multigroup confirmatory factor analysis across both the Canadian and Singaporean adolescent samples. The results suggested cross-cultural invariance of form, factor loadings, and factor variances and covariances of the AESI across both samples. Evidence of AESI's convergent and discriminant validity was also reported. Findings from t-tests revealed that Singaporean adolescents reported a significantly higher level of academic stress arising from self expectations, other expectations, and overall academic stress, compared to Canadian adolescents. Also, a larger cross-cultural effect was associated with academic stress arising from other expectations compared with academic stress arising from self expectations.     

Vascular endothelial growth factor in psoriasis: an indicator of disease severity and control

Background  Psoriasis is a chronic disease characterized by abnormal epidermal proliferation, inflammation and angiogenesis. It has been reported that vascular endothelial growth factor (VEGF) is overexpressed in lesional psoriatic skin and its serum levels are significantly elevated in patients with moderate to severe disease.
Objective  This study aims to evaluate the possible role of VEGF in the pathogenesis of psoriasis, and its significance as an indicator of disease severity and control.
Methods  Thirty patients with moderate to severe psoriasis and 10 healthy controls were subjected to baseline evaluation of VEGF. Patients were divided into three groups according to the received treatment: psoralen plus ultraviolet A (PUVA) thrice weekly (group 1), acitretin 50 mg daily (group 2), and combined PUVA twice weekly and acitretin 25 mg daily (group 3).Treatment continued for 16 weeks or up to clinical cure. Every patient was subjected to severity evaluation by Psoriasis Area and Severity Index (PASI) and measurement of serum VEGF before and after treatment.
Results  Mean serum levels of VEGF were significantly elevated in patients (327 ± 66.2 pg/mL) than control subjects (178 ± 83.4 pg/mL). A highly significant correlation was found between VEGF and PASI score, but not with other variables. The best clinical response, the least side-effects and the highest reduction of VEGF serum levels were achieved by the combined therapy.
Conclusion  The present study supported the proposed role of VEGF in the pathogenesis of psoriasis, and suggested that it could serve as a good indicator of disease severity and control.     

学习障碍患儿血清BDNF水平的研究

目的探讨学习障碍血清脑源性神经营养因子(BDNF)水平的变化,及其与学习障碍病理基础的关系。方法患者组为22例未治疗过且不共患其他疾病的学习障碍患儿,对照组为16例年龄性别匹配正常儿童,以瑞文标准推理测验(SPM)测定智商,BDNF采用酶联夹心免疫吸附法检测。结果LD患者血清BDNF浓度为:平均(4.603±3.620)ng/ml高于对照组(1.843±0.728)ng/ml(t=3.326,P=0.003<0.01)。边缘智商组(4.523±4.618)ng/ml,与正常对照组比较差异有非常显著性(P=0.008<0.01)。结论学习障碍患儿血清BDNF浓度高于正常儿童,边缘智商者升高更明显。     

The high prognostic value of the histologic grade at the deep invasive front of tongue squamous cell carcinoma

BACKGROUND: Although many histopathologic factors in squamous cell carcinoma of the tongue predict the prognosis, the major predictive factors have not been identified clearly. This study analyzed the prognostic value of the histologic grade at the deep invasive front of tongue squamous cell carcinoma. METHODS: The clinicopathologic features of 124 consecutive patients seen between January 1985 and December 1999 with previously untreated squamous cell carcinoma of the tongue were reviewed. Their mean age was 58.5 years (range: 23-90) and the male-female ratio was 1.8: 1 (79 men and 45 women). There were 41, 40, 30, and 13 cases at stage I to stage IV, respectively. The clinicopathologic factors, especially the histologic grade at the deep invasive front (invasive front grade, IFG), were analyzed to determine factors predicting prognosis. RESULTS: The 5-year disease-free survival rate of the patients treated with curative aim only was 66.7%. Clinicopathologic factors significantly associated with the prognosis were T classification, tumor size, stage classification, tumor depth, macroscopic appearance, cervical lymph node metastasis (nodal metastasis), microvascular invasion, and IFG. In a multivariate analysis, patients with tumor depth >/=4 mm, IFG >/=8 points, and nodal metastasis had a reduced disease-free survival and IFG >/=11 points had a predictive value for nodal metastasis (odds ratio: 7.34; P = 0.0019). CONCLUSION: This study found that a high IFG malignancy score had a high prognostic value for squamous cell carcinoma of the tongue.     

碳纤维根管桩的研制

目的研究高强度碳纤维增强复合树脂根管桩的加工成型工艺.方法用湿法制备碳纤维预浸料,在预成型模具中预成型,然后在成型模具中经特殊的工艺进行成型,最后用车床加工成预定形状的桩钉;并测试其弯曲强度、剪切强度和碳纤维含量.结果随着碳纤维含量的增加,根管桩的弯曲强度和剪切强度均逐渐增加.碳纤维含量达到67.13%时,弯曲强度和剪切强度分别达到406MPa和653.86MPa.结论高强度的碳纤维根管桩可以满足临床需要.     

11^C-蛋氨酸的体内生物学分布和初步临床应用

目的研究新型脑肿瘤显像剂：11^C-蛋氨酸（11^C-MET）的体内生物学分布，探讨11^C—MET的临床显像方法及其在脑肿瘤显像中的应用．方法测定11^C—MET在小鼠体内的分布，对健康志愿者和病理证实胶质瘤患者进行PET脑显像．结果小鼠体内分布实验和脑PET显像发现，11^C—MET在血液中清除较慢，在肿瘤内有较长的滞留时问，平台期位于30—45min之间，延迟相对有利于脑瘤的显像，其余放射性主要集中在消化系统．结论11^C—MDT有较高的肿瘤／脑比值，是理想的脑肿瘤显像剂．     

脐血单核细胞对VD大鼠认知功能及脑组织BDNF的影响

目的观察颈内动脉输注脐血单核细胞(Human cord blood mononuclear cells,HCMNCs)对血管性痴呆(Vascular dementia,VD)大鼠认知功能及脑组织脑源性神经营养因子(Brain-derivedneurotrophicfactor,BDNF)含量的影响。方法改良Pulsinellis四血管阻断法建立VD大鼠模型;体外分离HCMNCs,术后24h颈内动脉输注数量为3×106/0.5ml的BrdU标记细胞;利用穿梭箱系统和ELISA法检测注射HCMNCs后2、4、8周VD大鼠学习记忆能力以及脑组织BDNF含量的变化。结果模型组大鼠主动回避反应比率明显低于对照组(P<0.01),治疗组较模型组显著提高(P<0.01)。术后2周模型组大鼠脑组织BDNF含量较对照组明显增高(P<0.01),4周时达到高峰(P<0.01),8周时则明显下降,与2周时相比有显著性差异(P<0.05);颈内动脉输注HCMNCs后治疗组大鼠脑组织BDNF含量较模型组显著升高(P<0.01),4周时最高(P<0.01),8周时略有下降,但仍维持在较高水平,与4周时相比无显著性差异(P>0.05)。结论颈内动脉输注HCMNCs可显著改善VD大鼠学习记忆能力,增加VD大鼠脑组织BDNF含量,具有脑保护作用。     

Angiolipoma of the buccal mucosa: a possible role of mast cell-derived VEGF in its enhanced vascularity

A case of angiolipoma occurring in the buccal mucosa of a 69-year-old male is described. The patient had noticed a painless mass in his buccal mucosa for 2 years. The surgically removed tumor, measuring 9 mm in diameter, was mainly located in the submucosal layer with focal expansion into the muscle layer. Histologically, the tumor was well-demarcated and composed of proliferations of mature fat cells and fibrous connective tissue containing many small blood vessels, which were evenly distributed. There was diffuse infiltration of a large number of mast cells, which were immunopositive for vascular endothelial growth factor (VEGF) especially around blood vessels, suggesting that VEGF produced by mast cells in angiolipomas plays an important role in the vascular proliferation in this particular tumor.