高等医学院校计算机基础知识无纸化考试研究

我国高等医学院校计算机基础知识的教学,近年来有了很大的发展,但对应的考试测评相对滞后.对此,我们对无纸化考试应具备的条件、环境、考生、试题要求和安全性等几个方面进行了研究.     

Turbulent stress measurements downstream of three bileaflet heart valve designs in pigs

Objective: Mechanical heart valves can cause thromboembolic complications, possibly due to abnormal flow patterns that produce turbulence downstream of the valve. The objective of this study was to investigate whether three different bileaflet valve designs would exhibit clinically relevant differences in downstream turbulent stresses. Methods: Three bileaflet mechanical heart valves (Medtronic Advantage^®, CarboMedics© Orbis™ Universal and St. Jude Medical^® Standard) were implanted into 19 female 90 kg pigs. Blood velocity was measured during open chest conditions in the cross sectional area downstream of the valves with 10 MHz ultrasonic probes connected to a modified Alfred^® Pulsed Doppler equipment. As a measure of turbulence, Reynolds normal stress (RNS) was calculated at three different cardiac output ranges (3–4, 4.5–5.5, 6–7 L/min). Results: Data from 12 animals were obtained. RNS correlated with increasing cardiac outputs. The highest instantaneous RNS observed in these experiments was 47 N/m², and the mean RNS taken spatially over the cross sectional area of the aorta during systole was between 3 N/m² and 15 N/m². In none of the cardiac output ranges RNS values exceeded the lower critical limit for erythrocyte or thrombocyte damage for any of the valve designs. Conclusions: Reynolds normal stress values were below 100 N/m² for all three valve designs and the difference in design was not reflected in generation of turbulence. Hence, it is unlikely that any of the valve designs causes flow induced damage to platelets or erythrocytes.     

New perspectives for the use of contrast-enhanced liver ultrasound in clinical practice

The introduction of second-generation microbubble ultrasound contrast agents and the development of contrast specific ultrasound techniques have improved the ability of contrast enhanced ultrasound in detecting and characterising liver lesions, offering new perspectives for its exploitation in clinical hepatology. Indeed, several studies have demonstrated a high diagnostic accuracy in focal lesion characterisation (85-96%) in patients either with or without underlying chronic liver disease. This review article describes the basic principles of contrast enhanced ultrasound, defines the different vascular features of benign and malignant liver lesions, and assesses its clinical impact in different clinical scenarios, according to the guidelines of the European Federation of Societies for Ultrasound in Medicine and Biology, contrast enhanced ultrasound enables the characterisation of focal liver lesions, regardless of the presence or absence of underlying chronic liver disease. Contrast enhanced ultrasound is also useful in staging and follow-up of cancer patients and in monitoring local ablative treatment. Contrast enhanced ultrasound is expected to be considerably increased and replace many computed tomography and magnetic resonance imaging examinations in near future, according to the European Federation of Societies for Ultrasound in Medicine and Biology guidelines. Therefore, it is necessary to take measures in order to meet the demand for an increasing number of these procedures.     

Prevalence of elevated serum prostate-specific antigen in rural Nigeria

BACKGROUND: Recent hospital and cancer registry data show increasing prostate cancer incidence in Nigeria, which was previously regarded as a low incidence region. This study investigates the prevalence of prostate cancer risk in a previously unscreened cohort of rural Nigerians. METHODS: Rural Nigerian men, 40 years and older, were screened by serum prostate-specific antigen (PSA) and digital rectal examination (DRE) and those with PSA >/= 4 ng/mL and/or abnormal DRE were referred for prostate biopsy. RESULTS: Of 200 consecutive men invited, 151 (75.5%) presented for screening, the mean age was 56.45 + 15.1 and 95 (61.6%) were >/= 50 years of age. Of the 140 who consented to a blood test, PSA correlated with age (r = 0.3, P < 0.01), 14 (10.0%) had abnormal PSA >/= 4 ng/mL, increasing from 3 (3.6%) in men < 60 years to 4 (50%) in men >/= 80 years. The rate was 13 (15.7%) for men >/= 50 years and there was no evidence of increased incidence of prostatitis in the community. Mean (median) PSA in ng/mL increased from 1.17 (0.60) in the youngest to 13.75 (4.45) in the oldest cohort. Of those who accepted DRE, 38 (29.0%) had an enlarged prostate, including two who had nodular prostate, one-third with symptoms, increasing from 4 (5.4%) in those < 50 years to 6 (75.0%) in men >/= 80 years. The proportion of men with PSA >/= 4 ng/mL among those with enlarged vs normal prostate is 27.0 to 3.4%, P < 0.001, and the pattern was similar for men >/= 60 years and those < 60 years of age. The 40 (32.0%) men referred for prostate biopsy defaulted mainly because they did not fully understand the need for further investigation because they were symptom free or afraid of the possible side-effects of the procedure or diagnosis of cancer. CONCLUSION: The proportion of men with PSA >/= 4 ng/mL is comparable to that of previously unscreened populations with high incidence of prostate cancer such as African-American men. A larger study is required to confirm these findings and intensify efforts to determine the prostate cancer detection rate by biopsy in this population. A prostate cancer awareness and education campaign will be useful in this community.     

火针刺血疗法的临床应用心得

目的:探讨火针刺血疗法在临床的应用价值。方法:对实践经验和临床资料进行分析。结果:火针刺血疗法疗效快无不良反应。结论:火针刺血疗法对寒凝血瘀证疗效较好。     

Ultrasonographic findings in gastric cancer: in vitro and in vivo studies

Ultrasonography was performed in 45 cases of gastric cancer. Specimens from all 45 cases of gastric cancer were subjects to ultrasonographic study by the water immersion method for comparison with histology. In 32 of these 45 cases in vivo ultrasonographic evaluation was performed prospectively. The overall accuracy rates for the diagnosis of the depth of cancerous invasion were almost 80% in both in vitro and in vivo studies. In vivo ultrasonographic findings agreed well with those from the specimen studies. Ultrasonography was considered to be useful in the diagnosis of gastric malignancies.     

浙江省台州市路桥区从业人员乙肝病毒标志物检测的调查分析

目的：了解路桥地区2004年至2006年之间,从业人员健康人群HBsAg、HBsAb的阳性率及大、小三阳所占的比例。方法：对32 490人来体检的健康人群进行乙肝三系二对半检测,采用酶联免疫法（ELISA）测定HBsAg、HBsAb、HBeAg、HBeAb、HBcAb,按不同性别、城区与乡镇之间、两年之间进行比较。结果：不同性别之间HBsAg、HBsAb的阳性率无显著性差异。城区与乡镇之间HBsAg、HBsAb阳性率有显著性差异。两年之间HBsAg的阳性率有下降趋势。大小三阳的比例在各组之间也各不相同。结论：健康人群的乙肝病毒携带率比例偏高,易感者多,相关部门应督促乙肝疫苗的注射,减少乙肝发病率。     

Influence of Bone Quality on Precision of Calcaneal Ultrasonometry

This study was designed to determine the changes in precision of the ultrasound parameters speed of sound (SOS), broadband ultrasound attenuation (BUA), and stiffness index (SI) as a function of bone quality. The instrument used in this investigation was the LUNAR Achilles. Of the 608 female patients who had paired measurements with repositioning, 200 had t scores ≥−1 and 408 had t scores ≤−2.5, thus rendering a normal and a grossly abnormal group for comparison of precision results. It was found that the median precision error (CV%) for BUA was 1.99% for normal bone and 1.44% for abnormal bone (P= 0.02). No significant difference was obtained between median precision errors in normal and abnormal bone for the parameters SOS and SI, which were 0.23% and 0.19%, and 2.15% and 2.02%, respectively. In the interquartile range, the mean precision errors for SOS and BUA were significantly different in normal and abnormal bone: SOS was 0.25% and 0.21%, respectively, and BUA was 2.31% and 1.85%, respectively. No significant change was registered for SI. Precision error appears to decrease slightly at lower values for calcaneal variables. Received: 21 August 1996 / Accepted: 5 March 1997     

Diffuse liver disease: MRI with Gd-DTPA versus CT and ultrasound

Twenty-nine patients with diffuse liver disease were examined by ultrasound, CT and MRI. MRI was performed using T1- and T2-weighted spin-echo sequences as well as fast gradient-echo-sequences. The paramagnetic contrast agent Gd-DTPA was applied intravenously (0.1 mmol/kg). in patients with hepatitis, MRI could be used in guiding liver biopsies as inflammatory changes were clearly delineated. CT and ultrasound were superior to MRI in the detection of focal or diffuse fatty degeneration. On the other hand MRI was more helpful in differentiating fatty changes and neoplasm. In liver cirrhosis, fibrotic changes were most clearly demonstrated by MRI. In patients suffering from hemochromatosis MRI offers advantages over CT and ultrasound in the diagnosis and follow up due to the paramagnetic properties of iron, resulting in a reduction in signal intensity. In patients with Wilson's disease a characteristic pattern of parenchymal changes was seen. Administration of Gd- DTPA contributes additional information about perfusion conditions in the liver parenchyma, however this information was not of diagnostic relevance in the cases we studied. Correspondence to: T.J. Vogl     

X-linked hypophosphatemia: Normal renal function despite medullary nephrocalcinosis 25 years after transient vitamin D2-induced renal azotemia

Nephrocalcinosis (NC) detected by ultrasound is a recognized abnormality for some patients with X-linked hypophosphatemia (XLH) who received vitamin D₂ and inorganic phosphate therapy, but is commonly observed in XLH patients treated with 1,25-dihydroxyvitamin D₃ and inorganic phosphate supplementation. Nevertheless, long-term follow-up of kidney function in XLH patients with NC detected ultrasonographically has not been reported. We investigated two women with XLH, ages 31 (patient 1) and 39 (patient 2) years, each of whom had suffered at least one documented episode of vitamin D₂-induced hypercalcemia and renal azotemia during childhood. Patient 2 had also been treated with inorganic phosphate. No medications for XLH had been taken during adulthood. Renal ultrasonography at our institution demonstrated marked bilateral medullary NC in both women. No other explanation was found for their NC that apparently occurred several decades earlier from medical therapy for XLH. Detailed studies (including creatinine clearance, β₂-microglobulin excretion, and fasting urinary osmolality and acidification) revealed no impairment of kidney function in either patient. Our findings indicate that subradiographic medullary NC acquired during medical therapy for XLH may persist for decades, but with no adverse renal sequelae. Definitive (long-term) assessment of kidney function in the XLH population with NC, however, will be necessary to fully understand the risk of current medical treatment for this most common heritable form of rickets.