安氏Ⅱ类1分类患者拔牙或非拔牙矫治后长期面形变换

通常认为Ⅱ1错拔除4个第一前磨牙后,面形会变平或凹陷,但有些研究不支持这种观点.本实验目的就是评价拔牙与非拔牙治疗后和长期保持期间的面部软组织变化. 材料和方法63名美国白人,23名拔牙者(男11,女12),平均年龄12.6岁,40名非拔牙者(男19,女21),平均年龄11.3岁,牙列完整,均采用方丝弓矫治器治疗.开始时采用颈牵引抑制上颌生长,内收切牙.拍摄治疗前(T1)、治疗后(T2)和长期保持后(T3)13～14年期间的颅颌定位X线侧位片,进行有关测量比较各个时期治疗和生长的关系、切牙和唇的变化、拔牙与否的影响. 结果治疗前拔牙与非拔牙组LI-APg、LI-NB(mm)、LI-NB、NAPg有显著差异,显示拔牙组下切牙位置更靠前,颏部更突出.治疗期间以关节点位置变化表示的下颌生长,T1-T2期间6.24 mm,T2-T3期间4.62 mm. 矫治前后拔牙与非拔牙组比较,LI-APg、LI-NB(mm)、LI-NB、LL-E、LL-S等指标两组间差异有显著性,说明拔牙组治疗期间下唇及下切牙更向后移动,而上唇后移、下颌及鼻部生长、颏部向前,两组间差异无显著性. 矫治保持阶段,拔牙与非拔牙组均显示上下唇位置后移,软组织颏部更向前,两组间比较差异无显著性;鼻部生长、下颌生长两组间测量也无差异. 结论经拔牙或不拔牙成功治疗的安氏Ⅱ类1分类患者治疗后及保持期间面形持续变平,面部软组织突度进一步减小,这是由于下颌和鼻部生长所致,而不是拔牙与否的影响.长期保持后,唇的位置比Ricketts等倡导的理想位更后移,但与未治疗的同年龄组成人相似,治疗前下唇位置和厚度及上下颌骨关系可作为预测治疗后及长期保持期间下唇位置的因素. [蔡留意摘 丁寅校]     

Effects of platelet inhibitors on the platelet aggregation induced by plasma from patients with thrombotic thrombocytopenic purpura

Antiplatelet drugs have been used in the treatment of thrombotic thrombocytopenic purpura (TTP) but there in vivo efficacy remains controversial. It has been shown that, in vitro, the plasmas obtained from patients with TTP induced the aggregation of washed platelets from normal donors as well as patients in remission. The effects of platelet inhibitors on the TTP plasma-induced platelet aggregation were examined. It was found that aspirin, indomethacin, ibuprofen, sulfinpyrazone, 5, 8, 11, 14-eisacotetraynoic acid, prostaglandin E1, prostaglandin I2, dBcAMP, apyrase, creatine phosphate/creatine phosphokinase, antimycin, 2-deoxy-D-glucose, dipyridamole, clofibrate, dextran 40, dextran 70, dibucaine, xylocaine, methylmaleimide, and ethylenediamine tetraacetic acid had little or no effect at all. These data lead us to conclude that at least in certain cases, antiplatelet drugs probably play a limited role in the treatment of patients with TTP.     

Blood transfusion costs: a multicenter study

The cost of delivering a unit of blood (whole blood or red cells) to a hospitalized patient was examined in 19 United States teaching hospitals. The average hospital acquisition cost was calculated by using the prices charged by regional blood centers for blood products. To this cost was added an estimate of costs incurred by hospitals for handling, testing, and administering blood. Across study sites, the average hospital cost per unit transfused was $155 and the average charge to the patient was $219. Acquisition cost, the price that hospitals pay for blood, was 37 percent of the total cost to the hospital; the other 63 percent of the hospital cost included costs for blood bank handling (13%), laboratory tests (43%), and blood administration (7%). Significant variations in blood transfusion cost were found within our sample. Most of the variability can be attributed to geographic location of the blood supply source, type of red cell product transfused, prices charged by blood transfusion services, and the frequency of laboratory tests. The results of this transfusion cost study may be helpful in determining the costs of health care delivery, especially when blood transfusions are indicated.     

Palpable prostatic nodules: comparison of US and digital guidance for fine-needle aspiration biopsy

This study was undertaken to evaluate the use of transrectal sonographically guided fine-needle aspiration biopsy and to compare sonographic with digital guidance for biopsy. In 62 patients in whom prostatic carcinoma was suspected at digital rectal examination, fine-needle aspiration biopsies were performed transperineally under sonographic guidance and transrectally under digital guidance. These patients had 89 nodules, 73 of which were sampled with both techniques. Malignant cells were obtained under digital guidance in 17 of 73 nodules (23%) and under sonographic guidance in 16 (22%). An additional seven nodules, which were not seen sonographically, were sampled under digital guidance and proved to be negative. In nine other nodules that were nonpalpable and evident only with sonography, malignant cells were obtained under sonographic guidance in three. These findings indicate that sonographic guidance for fine-needle aspiration biopsy is as good as digital guidance for palpable lesions.     

Spinal cord compression due to metastatic disease: diagnosis with MR imaging versus myelography

To determine the efficacy of magnetic resonance (MR) imaging and myelography for the diagnosis of spinal cord compression due to metastatic disease, the authors prospectively examined 70 patients who had known or suspected spinal involvement by malignancy. Most MR examinations consisted of T1-weighted sagittal imaging of the entire spine, with additional sequences as needed for clarification. Extradural masses were found in 46 patients, 25 of whom had cord compression. For extradural masses causing cord compression, the sensitivity and specificity of MR imaging was .92 and .90, respectively, compared with .95 and .88 for myelography. For extradural masses without cord compression the sensitivity and specificity of MR imaging was .73 and .90, versus .49 and .88 for myelography. MR imaging was much more sensitive for metastases to bone (.90 vs .49), as expected. MR imaging is an acceptable alternative to myelography for diagnosing spinal cord compression and is preferable as a first study because it is noninvasive and better tolerated.     

Pharmacokinetics in obese patients

One of the many problems in providing anaesthesia for morbidlyobese patients is the influence of obesity on pharmacokineticsand pharmacodynamics. Drug administration in obese patientsis difficult because recommended doses are based on pharmacokineticdata obtained from individuals with normal weights; therefore,mistakes in the determination of the appropriate dose are oftenmade. Because of comorbidity in these patients, the functionof organs involved in drug elimination (e.g. kidney, liver)can be affected making pharmacokinetics more difficult and complex.     

Serial lung scintigraphy: utility in diagnosis of pulmonary embolism

Pairs of sequential perfusion lung scans and pulmonary angiograms obtained in 45 patients were reviewed to investigate the utility of short-term, sequential scintigraphy in the diagnosis of pulmonary embolism (PE). Forty-six sequential scan pairs were reviewed; 13 were ventilation-perfusion (V-P) pairs. Angiograms were obtained within 48 hours of either the first (65%) or second (35%) perfusion scan in each pair. Sequential scintigraphic patterns were classified as showing change (i.e., improvement in defects, new defects), no change, or as being indeterminate. A changing perfusion pattern was associated with a high (20/23) likelihood of PE, but seven of 16 patients with stable perfusion patterns also had PE. The sensitivity of a changing perfusion pattern for PE was 0.74 (20/27) and its specificity was 0.75 (9/12). In two of six patients who had serial V-P studies that showed changing perfusion defects, there were matched changes in regional ventilation and angiograms were negative. The findings suggest that short-term serial perfusion lung scanning may aid the scintigraphic diagnosis of PE in certain circumstances. Serial V-P imaging is needed, however, to maximize diagnostic specificity.     

Erosive potential of beverages sold in Australian schools

Background:  Dental erosion is an increasingly prevalent problem in Australia. The aim of this study was to analyse the composition and erosive potential of beverages sold for consumption in Victorian schools.
Methods:  Fifteen drinks were selected and analysed to determine their pH, titratable acidity and ionic composition (calcium, fluoride and inorganic phosphate). The erosive potential of the beverages was measured by analysing weight loss, surface loss and the release of calcium ions from human enamel following a 30-minute or 24-hour exposure. The association of the chemical parameters with the measures of erosion was determined using Spearman's rank correlation.
Results:  All beverages tested except the milks and the bottled water produced significant dental erosion in vitro . The only chemical parameter that correlated significantly with all measures of erosion was the initial pH of the beverage (p < 0.01). Levels of fluoride similar to those of Australian reticulated water were found in the carbonated beverages.
Conclusions:  The majority of the tested beverages sold from school canteens exhibited erosive potential.