麦冬类中药组织切片计算机三维重建图鉴

利用计算机技术实现麦冬类中药组织连续切片三维重建与动态显示,为计算机辅助生药学鉴定和教学提供了新的三维图像技术和研究资料。     

Gastro-oesophageal reflux disease: Medical or surgical treatment? Report of an interactive workshop

Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.     

Low-artifact intravascular devices: MR imaging evaluation

Flow-phantom magnetic resonance (MR) imaging, with use of both spin-echo (SE) and gradient-echo (GRE) techniques at 1.5 T, was performed on the percutaneous Greenfield (beta-III titanium alloy [TMA wire]), Amplatz (MP32-N alloy), and Simon nitinol filters and TMA wire facsimiles of the bird's nest, Gunther, new retrievable, and Amplatz vena caval filters. SE imaging allowed detection of thrombi as small as 5 X 5 mm trapped within the percutaneous Greenfield, Simon nitinol, and TMA-wire facsimile filters; with the MP32-N Amplatz filter, a larger volume of thrombus (10 X 20-mm clots) was necessary for clot detection. GRE imaging allowed detection of intraluminal tilting of the percutaneous Greenfield and facsimile Amplatz (TMA-wire) filters. GRE imaging was useful for demonstrating postfilter turbulence due to clots, which was greatest for the Amplatz filter. Imaging of facsimile vascular devices made of tantalum or TMA wire did not cause the severe "black-hole" MR artifacts typical of the stainless-steel devices. SE and GRE imaging were very useful for determining caval patency in two patients with previously placed Mobin-Uddin filters. Noninvasive MR evaluation of blood vessels in the presence of a variety of low-artifact intravascular devices appears feasible.     

Management of infectious waste by US hospitals

In July 1987 and January 1988, forty-six percent (441/955) of randomly selected US hospitals responded to a questionnaire intended to identify their waste disposal practices. Survey responses were received from hospitals in 48 states. United States hospitals generated a median of 6.93 kg of hospital waste per patient per day and infectious waste made up 15% of the total hospital waste. Most hospitals (greater than 90%) considered blood, microbiology, "sharps," communicable disease isolation, pathology, autopsy, and contaminated animal carcass waste as infectious. Other sources of hospital waste that were commonly (greater than 80%) designated infectious were surgical, dialysis, and miscellaneous laboratory waste. The infectious waste was normally (80%) treated via incineration or steam sterilization before disposal, whereas noninfectious waste was discarded directly in a sanitary landfill. Eight-two percent of these US hospitals are discarding blood, microbiology, sharps, pathology, and contaminated animal carcass waste in accordance with the Centers for Disease Control's recommendations, while the compliance rate for the Environmental Protection Agency's recommendations (excluding optional waste) is 75%. No hospital could identify an infection problem (excluding needle-stick injuries) that was attributable to the disposal of infectious waste. While the management of infectious waste by US hospitals is generally consistent with the Centers for Disease Control's guidelines, many hospitals employ overly inclusive definitions of infectious waste.     

Sequence comparison of human and yeast telomeres identifies structurally distinct subtelomeric domains

We have sequenced and compared DNA from the ends of three human chromosomes: 4p, 16p and 22q. In all cases the pro-terminal regions are subdivided by degenerate (TTAGGG)n repeats into distal and proximal sub- domains with entirely different patterns of homology to other chromosome ends. The distal regions contain numerous, short (<2 kb) segments of interrupted homology to many other human telomeric regions. The proximal regions show much longer (approximately 10-40 kb) uninterrupted homology to a few chromosome ends. A comparison of all yeast subtelomeric regions indicates that they too are subdivided by degenerate TTAGGG repeats into distal and proximal sub-domains with similarly different patterns of identity to other non-homologous chromosome ends. Sequence comparisons indicate that the distal and proximal sub-domains do not interact with each other and that they interact quite differently with the corresponding regions on other, non- homologous, chromosomes. These findings suggest that the degenerate TTAGGG repeats identify a previously unrecognized, evolutionarily conserved boundary between remarkably different subtelomeric domains.      

Incidence and occurrence of total (first-ever and recurrent) stroke

BACKGROUND AND PURPOSE: It has recently been hypothesized that the figure of approximately half a million strokes substantially underestimates the actual annual stroke burden for the United States. The majority of previously reported studies on the epidemiology of stroke used relatively small and homogeneous population-based stroke registries. This study was designed to estimate the occurrence, incidence, and characteristics of total (first-ever and recurrent) stroke by using a large administrative claims database representative of all 1995 US inpatient discharges. METHODS: We used the Nationwide Inpatient Sample of the Healthcare Cost and Utilization Project, release 4, which contains approximately 20% of all 1995 US inpatient discharges. Because the accuracy of International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) coding is suboptimal, we performed a literature review of ICD-9-CM 430 to 438 validation studies. The pooled results from the literature review were used to make appropriate adjustments in the analysis to correct for some of the inaccuracies of the diagnostic codes. RESULTS: There were 682 000 occurrences of stroke with hospitalization (95% CI 660 000 to 704 000) and an estimated 68 000 occurrences of stroke without hospitalization. The overall incidence rate for occurrence of total stroke (first-ever and recurrent) was 259 per 100 000 population (age- and sex-adjusted to 1995 US population). Incidence rates increased exponentially with age and were consistently higher for males than for females. CONCLUSIONS: We conservatively estimate that there were 750 000 first-ever or recurrent strokes in the United States during 1995. This new figure emphasizes the importance of preventive measures for a disease that has identifiable and modifiable risk factors and for the development of new and improved treatment strategies and infrastructures that can reduce the consequences of stroke.     

Bacterial and mammalian DNA alkyltransferases sensitize Escherichia coli to the lethal and mutagenic effects of dibromoalkanes

Here we confirm and extend our previous studies demonstrating that the mutagenic potency of 1,2-dibromoethane (DBE) and dibromomethane (DBM) is markedly enhanced (not prevented) in bacteria expressing the O6- alkylguanine-DNA alkyltransferase (ATase) encoded by the Escherichia coli ogt gene. We demonstrate that, in close parallel with mutagenesis, the Ogt ATase sensitizes the bacteria to the lethal effects of these carcinogens, suggesting that one or more of the potentially mutagenic lesions induced by DBE and DBM in the presence of Ogt has additional lethal capacity. We further demonstrate that the sensitization to both lethality and mutagenesis by DBE and DBM is a property shared by other DNA alkyltransferases. This objective was accomplished by quantifying the induction of mutations and lethal events in ogt- ada- E. coli expressing an exogenous bacterial or mammalian ATase from a multicopy plasmid. Mammalian recombinant ATases enhanced the lethal and mutagenic actions of DBE and suppressed the lack of sensitivity of the vector- transformed bacteria to DBM. In most cases the order of effectiveness of the ATases ranked: murine > human > Ogt > rat. Further comparisons included the full-length Ada ATase from E. coli and a truncated Ada version (T-ada) that retains the O6-methylguanine binding domain of the protein. The full-length Ada ATase was effective in enhancing the lethality but not the mutagenicity induced by DBE and DBM. The T-ada ATase provided less sensitization than Ada to lethality by DBE, but of the three bacterial ATases T-ada yielded the highest sensitization to mutagenesis by this compound. T-ada and Ada ATases were in general less effective than the mammalian versions, with the exception of the rat recombinant ATase. The effectiveness of the different mammalian and bacterial ATases in promoting the deleterious actions of dibromoalkanes was compared with the effectiveness of these proteins in suppressing the lethal and mutagenic effects induced by N-nitroso-N-methylurea. The ability to sensitize E. coli to the lethal and mutagenic effects of DBE and DBM seems restricted to DNA alkyltransferase, since overexpression of thioredoxin (Trx) or glutaredoxin (Grx1) in ogt- ada- cells showed no effect, in spite of the reported potential of bioactive dihaloethane- derived species to alkylate Trx.