Immunomicroscopy: resin techniques and on-section labelling with immunocolloidal gold or immunoperoxidase--planning a protocol

On-section immunocytochemistry is divided into two parts: (i) processing of biological tissue for section microscopy and (ii) immunolabelling of sections. Many of the more successful microscopical methods employ delicate aldehyde fixation of biological tissue followed by "sympathetic" processing into an acrylic resin. Processing regimens do not have to be complicated. Simple and cost effective room temperature protocols utilising partial dehydration have been devised and they can be as effective as the more complex low temperature techniques in preserving both ultrastructure and antigenic reactivity. The embedded material can be investigated by either light or electron microscopy. Frozen sections can be cut and immunolabelled but only if the tissue is chemically fixed first, as in resin embedding. Fixation with low concentrations of aldehyde will normally better preserve tissue immunoreactivity but this may be at the expense of good ultrastructure with these protocols. If so, low temperature resin embedding methods or rapid freezing and cryosubstitution can be tried. The choice of processing protocol will determine which acrylic resin to use, as will the preference for subsequent immunolabelling with either colloidal gold or peroxidase/diaminobenzidine (DAB). Both types of labelling system offer advantages to localisation studies and can be used in combination for double or even triple labelling. Silver enhancement of the colloidal gold or DAB allows for improved observation by light microscopy.     

Direct Visualization of Deformation in Volumes

Deformation is a topic of interest in many disciplines. In particular in medical research, deformations of surfaces and even entire volumetric structures are of interest. Clear visualization of such deformations can lead to important insight into growth processes and progression of disease.
We present new techniques for direct focus+context visualization of deformation fields representing transformations between pairs of volumetric datasets. Typically, such fields are computed by performing a non-rigid registration between two data volumes. Our visualization is based on direct volume rendering and uses the GPU to compute and interactively visualize features of these deformation fields in real-time. We integrate visualization of the deformation field with visualization of the scalar volume affected by the deformations. Furthermore, we present a novel use of texturing in volume rendered visualizations to show additional properties of the vector field on surfaces in the volume.     

Evaluating meeting support tools

Many attempts are underway for developing meeting support tools, but less attention is paid to the evaluation of meetingware. This article describes the development and testing of an instrument for evaluating meeting tools. First, we specified the object of evaluation—meetings—by means of a set of input, process, and outcome factors. Then, we designed the process of evaluation, consisting of, first, the generation of meeting behavior in the form of a controlled series of meetings within the context of a project and, second, the measurement of the identified meeting factors. To measure these factors, a rating scale, questionnaires, and information flow analysis were used. Next, the instrument was tested, and the factors for successful meetings were determined in 13 projects in which four participants had to meet four times. The evaluation instrument proved to be a reliable and useful aid for the development and improvement of meeting tools.     

Gastric and biliary excretion of meperidine in man

The role and importance of enterogastric secretion in the disposition and elimination of the weak base, meperidine (pKa 8.63), was studied after intravenous administration (50 mg) of the drug to 6 normal volunteers. Continuous collection of the gastric fluid over a 4-hr period demonstrated the establishment of high gastric fluid/plasma concentration ratios for meperidine (mean about 50, range, 10 to 200). However, the total amount of drug recovered, even after correction for incomplete collection, was only a small percentage of the administered dose. Under basal conditions a mean +/- SE of 1.9 +/- 0.3 mg, equivalent to 3.7% of the administered dose, was found in the total gastric aspirate. Stimulation of gastric secretion by subcutaneous injection of betazole (1.5 mg/kg) increased this recovery to 3.6 +/- 0.3 mg (7.2%) primarily due to the increase in gastric volumen output. Aspiration of the gastric fluid in either the basal or stimulated situation had no observable effect upon the plasma concentration/time profile of meperidine whether assessed by the terminal half-life, t 1/2 beta, or the plasma clearance; control values were 3.8 +/- hr and 1,190 +/- 130 ml/min, respectively. In 2 subjects "bile fluid" was also collected for 2.5 hr and found to contain less than 0.2% of the administered dose. Enterosystemic recycling is therefore of minor importance in the disposition and elimination of meperidine in man.     

The heroin epidemic in San Francisco: estimates of incidence and prevalence

Much attention has recently been focused on the question of the extent of heroin use in America. In a worthwhile effort to call public attention to the problem, many estimates of its size have evidenced a tendency toward exaggeration and aggrandizement. This paper presents methods of estimation of the extent of heroin addiction which, when carefully employed, should effectively correct such distorted estimates. Two general types of estimation are employed, incidence and prevalence. Incidence estimates are concerned with new cases of heroin addiction that occur in a specific population within a given amount of time. These estimates are based upon self-report data from addicts regarding date of first addiction. When corrected for the "lag phase" (that period of time between onset of first addiction and eventual visit to a treatment program), these data permit accurate retrospective charting of incidence trends. Prevalence estimates focus on all known cases of heroin addiction in a specific population within a given amount of time. Three separate types of prevalence estimates from three separate sources are outlined in this article: estimates based on overdose death data, estimates based on crime statistics, and estimates of "unknown" addicts. In outlining these methods, this article describes the fluctuations in heroin addiction in one major American city, San Francisco, California. After analyzing data gathered from a sample of 2,367 addicts contacted over a 3-year period, this study suggests that the incidence of heroin addiction seems to have declined after 1970. Possible factors underlying this apparent decline in heroin addiction are then discussed, including the post-1970 maturation of the "population at risk," the effectiveness of antidrug media messages, the changing drug fashions in the heroin subculture, and the gradual deterioration of the quality and potency of street heroin.     

Percutaneous radiologic drainage of pancreatic abscesses

OBJECTIVE: The purpose of our study was to review and report the patient selection, techniques, and results of percutaneous drainage of pancreatic abscesses by retrospective review. MATERIALS AND METHODS: Fifty-nine patients (46 men and 13 women) with a mean age of 44 years old had 80 pancreatic abscesses that were drained percutaneously under radiologic guidance (CT, n = 77; sonography, n = 2; and fluoroscopy, n = 1). Abscesses had a wide spectrum of causes, with alcoholic pancreatitis being most common, trauma second most common, and gallstones third. Ten patients had undergone surgery for pancreatic necrosis or abscess. Patients with pancreatic pseudocysts, necrosis, or acute fluid collections were excluded from this study. RESULTS: Of the 59 patients, 51 (86%) were cured with percutaneous drainage and antibiotic therapy. Of the patients who were not cured with percutaneous drainage, seven required surgery and one underwent repeat percutaneous drainage. In the 59 patients, complications included non-life-threatening bleeding in three patients. Ten of 59 patients (17%) had fistulas that spontaneously formed into the gastrointestinal tract. The duration of catheterization ranged from 4 to 119 days, with a mean duration of 33 days. The rate of mortality at 30 days after completion of percutaneous drainage was 8% (5 of 59). CONCLUSION: Percutaneous drainage was an effective therapy for this defined group of patients with pancreatic abscesses. Factors leading to the relatively high success rate described in this study likely included selection of patients; catheters of adequate size, number, and location; careful follow-up with appropriate catheter manipulations; and an integrated, cooperative approach whereby surgeons were willing to permit drainage to effect its benefits, rather than operating prematurely.     

美国的下一代航空运输系统——发展愿景、成就与未来方向

1. Introduction The US Federal Aviation Administration (FAA) manages the lar-gest air traffic control system in the world. This system controls approximate...     

PRACTICAL INCONSISTENCY MANAGEMENT FOR CRITICAL-TASKS DECISION-SUPPORT SYSTEMS

Abstract

In this paper, the problem of logical consistency in critical-tasks decision systems is addressed. It is shown how local search techniques can be used to check the (in)consistency of very large propositional knowledge bases (KBs). Using new heuristic findings. we can now implement efficient forms of diagnostic reasoning in the context of very large ICBs modeling deep models of complex devices and including patterns of default reasoning.     

超音速喷嘴变工况性能分析与试验研究

采用数值模拟方法对超音速喷嘴的变工况性能进行了分析,研究了不同压比下速度系数以及喷嘴内部流场的变化规律得到了,设计工况下喷嘴的速度系数(0.96)和总压恢复系数(0.87)。为进一步掌握超音速喷嘴的气动性能,进行了平面叶栅风洞试验,测量了不同压比下叶片表面马赫数分布,结合数值模拟结果,分析了叶栅通道内的流场特性。在超音速喷嘴出口截面处,由于膨胀波组等因素的影响,吸力面将产生马赫数拐点,并随着压比的减小逐渐后移;当偏离设计压比时,叶栅吸力面将出现汽流分离;通过叶栅S1流面纹影照片,观察到了叶栅槽道内的波系构成,与数值模拟结果具有较高的一致性。试验结果验证了数值计算的准确性。