Neurofibromas: location by scanning with Tc-99m DTPA. Work in progress

The accumulation of technetium-99m diethylenetriamine pentaacetic acid (Tc-99m DTPA) in benign soft-tissue neurofibromatosis tumors is reported. In a series of 16 patients with clinical stigmata of neurofibromatosis, 28 sites of abnormal soft-tissue localization of the isotope observed scintigraphically were documented to be sites of soft-tissue tumor by clinical and/or radiographic (predominantly computed tomographic) correlations. The smallest lesion detected was a 1.5-cm subcutaneous neurofibroma. Normal physiologic nonrenal distribution of the Tc-99m DTPA was established by scintigraphic imaging of a control population.     

Central nervous system lesions in pediatric patients: Gd-DTPA-enhanced MR imaging

Twenty pediatric patients, aged 2-18 years, with known or suspected masses in the brain and/or spinal cord were studied with magnetic resonance imaging at 0.6T with and without use of 0.1 mmol/kg gadolinium diethylenetriaminepentaacetic acid (Gd-DTPA). The multisection, multiecho imaging mode was utilized. Surgically proved mass lesions included astrocytoma (n = 6), medulloblastoma (n = 2), ependymoma (n = 1), craniopharyngioma (n = 1), oligodendroglioma (n = 1), germinoma (n = 1) and fibrosarcoma (n = 1). Presumptive diagnoses included astrocytoma (n = 3), arachnoid cyst (n = 1), tuberous sclerosis (n = 1), cryptic vascular malformation (n = 1), and normal (n = 1). There was dramatic enhancement in 11 of 20 patients, with improved definition of the presence and extent of lesions in six patients. No adverse effects were noted in any of the 20 patients. It is concluded that Gd-DTPA is useful in delineating the presence, extent, and number of certain lesions of the central nervous system in children.     

Early gastric cancer. Recent experience

Early gastric cancer (EGC) is defined as carcinoma in which malignant invasion is limited to the mucosa or submucosa. Records of pathologic examinations from the Hospital of the University of Pennsylvania show that EGC comprised 6% of all gastric carcinomas diagnosed between 1977 and 1983 (7/118 cases) compared with 8.2% of gastric carcinomas diagnosed between 1965 and 1977 (12/147 cases). Double contrast radiographic techniques and fiberoptic endoscopy became widely available at our institution in 1976. Thus, the application of these techniques to symptomatic patients has not improved our ability to diagnose EGC. In contrast, the incidence of EGC in Japan has risen from 5% to 35% with the widespread use of these diagnostic techniques. This discrepancy can be attributed to mass screening of asymptomatic patients in Japan because of the unusually high prevalence of gastric carcinoma in that country. American radiologists and endoscopists should therefore recognize that they are unlikely to experience a significant increase in the detection of EGC as long as these examinations are performed predominantly on symptomatic patients.     

Behaviour of a population of partially duplicated mitochondrial DNA molecules in cell culture: segregation, maintenance and recombination dependent upon nuclear background

We have studied the dynamics of mitochondrial DNA maintenance and segregation in human cells using serial cybrid transfer of partially duplicated mitochondrial DNA, from a mitochondrial myopathy patient, to two distinct recipient cell types. The results indicate two radically different outcomes dependent upon nuclear background. In one case (lung carcinoma) there is systematic loss of the partial duplication by an implied recombinational mechanism. In another nuclear background (osteosarcoma) the duplicated molecules can survive, having only a marginal effect on mitochondrial respiratory function. Moreover, in the osteosarcoma nuclear background further disturbances of mtDNA maintenance frequently follow from cybrid transfer. These are progressive, catastrophic loss of mtDNA and further rearrangement to generate partially triplicated molecules. The results imply differential expression of nuclear genes regulating mtDNA copy number, replication and recombination in different human cell types.      

O04 Four-Year experience of Pharmacology Teaching in the Integrated Curriculum at Taipei Yang-Ming University

National Yang-Ming University was established in 1971 at Taipei. We mainly train 7- year medical students immediately after high school education. Originally, the 4^th year students received their pharmacology teaching by an intensive course within one semester （4 hours/wk）. We covered all 66 chapters in ＂Basic ＆ Clinical Pharmacology＂, with a total 72 lecture hours. In order to design a problem-based learning course for all the courses of previous 4^th year students, our pharmacology teaching must re-organize in this integrated curriculum from the year of 2001. The major changes include： decreasing total lecture hour （from 72 to 58）, one semester course becoming one-year course （roughly 2 hours/wk）, merely covering 80% of all 66 chapters in the textbook. We did student survey each year and the results will be presented in our presentation. Also, the advantages and disadvantages for this reform will be discussed.     

HIV and risk of venous thromboembolism: a Danish nationwide population‐based cohort study

Objective

The association between HIV infection and the risk of venous thromboembolism (VTE) is controversial. We examined the risk of VTE in HIV‐infected individuals compared with the general population and estimated the impact of low CD4 cell count, highly active antiretroviral therapy (HAART) and injecting drug use (IDU).

Methods

We identified 4333 Danish HIV‐infected patients from the Danish HIV Cohort Study and a population‐based age‐ and gender‐matched comparison cohort of 43 330 individuals. VTE diagnoses were extracted from the Danish National Hospital Registry. Cumulative incidence curves were constructed for time to first VTE. Incidence rate ratios (IRRs) and impact of low CD4 cell count and HAART were estimated by Cox regression analyses. Analyses were stratified by IDU, adjusted for comorbidity and disaggregated by overall, provoked and unprovoked VTE.

Results

The 5‐year risk of VTE was 8.0% [95% confidence interval (CI) 5.78–10.74%] in IDU HIV‐infected patients, 1.5% (95% CI 1.14–1.95%) in non‐IDU HIV‐infected patients and 0.3% (95% CI 0.29–0.41%) in the population comparison cohort. In non‐IDU HIV‐infected patients, adjusted IRRs for unprovoked and provoked VTE were 3.42 (95% CI 2.58–4.54) and 5.51 (95% CI 3.29–9.23), respectively, compared with the population comparison cohort. In IDU HIV‐infected patients, the adjusted IRRs were 12.66 (95% CI 6.03–26.59) for unprovoked VTE and 9.38 (95% CI 1.61–54.50) for provoked VTE. Low CD4 cell count had a minor impact on these risk estimates, while HAART increased the overall risk (IRR 1.93; 95% CI 1.00–3.72).

Conclusion

HIV‐infected patients are at increased risk of VTE, especially in the IDU population. HAART and possibly low CD4 cell count further increase the risk.     

Rapid Preparation of High-Quality Frozen Sections Using a Membrane and Vacuum System Embedding Machine

BACKGROUND A wide variety of embedding techniques have been employed to process frozen sections for Mohs micrographic surgery. Prospective data comparing different techniques are lacking.
OBJECTIVE The purpose of this study was to compare tissue processing times and slide quality using the three embedding techniques.
METHODS Seventy-five consecutive Mohs surgery tissue specimens, measuring 1 cm in diameter, were prospectively randomized to processing with the CryoHist, the Cryocup, or the Miami Special. Tissue preparation times were recorded, and slide quality was evaluated. Tissue specimen preparation was standardized to exclude the use of relaxing incisions or other tissue manipulations. In a separate evaluation, slide quality was retrospectively evaluated for 50 large specimens (>2.5 cm) processed with the CryoHist machine.
RESULTS The mean tissue processing time was 11.4 minutes using the CryoHist, 12.9 minutes using the Cryocup, and 12.6 minutes using the Miami Special. Slide quality, using epidermal edge as a primary end point, was superior with the CryoHist compared to the other methods. For large (>2.5 cm) en bloc Mohs specimens processed using the CryoHist, the slide quality was excellent with 92.3% of epidermal edge obtained.
CONCLUSIONS The fully automated CryoHist embedding machine enables high-quality frozen sections to be processed in less time than the Cryocup or the Miami Special. Slide quality is excellent, even for larger specimens.     

Effects of dietary calcium on atherosclerosis, aortic calcification, and icterus in rabbits fed a supplemental cholesterol diet

Background  

Vascular calcification is implicated in myocardial infarction, instability and rigidity of the aortic wall, and bioprosthetic failures. Although an increase in the calcium (Ca) content in atherogenic diets has been shown to decrease atherosclerosis in rabbits, whether Ca supplementation and deficiency can affect atherosclerosis-related aortic calcification remains unknown.