On the susceptibility of human platelets to aggregation by concanavalin A and the effect of this lectin on their response to ADP

Concanavalin A aggregated gel-filtered platelets in 0.9% NaCl solution signifying cross-bridging by the lectin. Aggregation of these platelets by concanavalin A was temperature dependent; it did not occur at 0-4 degrees C unless the platelets were previously trypsinized. The level of aggregation of trypsinized platelets by concanavalin A at 0-4 degrees C was similar to that of untreated platelets at 37 degrees C. It is suggested that trypsin facilitates platelet aggregation by concanavalin A at 0-4 degrees C by causing a configurational change in membrane glycoproteins which orientates concanavalin A receptor sites into positions that favour lectin cross-bridging. Concanavalin A failed to aggregate platelets in plasma. Radioisotope studies showed that the amount of [3H]concanavalin A which combined with platelets in plasma was extremely low compared with gel-filtered platelets in saline. The aggregation of Ehrlich ascites cells by concanavalin A was considerably reduced when platelet-free plasma was added to the medium suggesting that it was due to the presence of concanavalin A-reactive components in the plasma. Concanavalin A inhibited the ADP-induced aggregation of platelets suspended in plasma or in a salts solution supplemented with calcium and fibrinogen, although the inhibitory effect was more conspicuous in the latter case. The results suggests that concanavalin A produces its inhibitory effect on ADP-induced platelet aggregation by interacting with membrane glycoproteins, and this further suggests their involvement in aggregation.     

A set of electrophoretic molecular markers for strain typing and population genetic studies of Histoplasma capsulatum

A set of eleven biallelic and three multiallelic molecular markers have been developed to analyze populations of Histoplasma capsulatum. All markers are amplified by polymerase chain reaction (PCR) and can be readily scored using minimal amounts of template DNA. The 11 biallelic loci have polymorphic restriction endonuclease sites or small insertions or deletions which may be assessed by agarose gel electrophoresis. These markers are inherited in an unambiguous manner and are ideal for assessing structure and gene flow within US populations of H. capsulatum, but are monomorphic in non-US populations. Both length and sequence variation are present in the multiallelic loci, which can be scored by direct sequencing, polyacrylamide gel electrophoresis, or single-strand conformation polymorphism (SSCP): As they are hypervariable, the multiallelic loci can be used to type isolates and to assess the level of genetic variation within populations. Preliminary results indicate that the three multiallelic markers presented are sufficient to distinguish isolates at the individual level and are polymorphic in both US and non-US populations. This collection of molecular markers will be a useful tool in population and epidemiology studies of H. capsulatum.     

过期药呋塞米在醋酸溶液中对冷轧钢的缓蚀作用

通过电导率测量、pH测量、同步热分析(STA)、Tafel极化曲线法和电化学交流阻抗谱法研究了不同浓度和温度下过期药呋塞米在1 mol/L的醋酸溶液中对冷轧钢缓蚀作用。实验结果表明:过期药呋塞米在1 mol/L的醋酸溶液中对冷轧钢有较好的缓蚀效果,且缓蚀率随着缓蚀剂浓度和温度的增加而增大。该缓蚀剂在醋酸中对钢是一种抑制阴极和阳极的混合型缓蚀剂。缓蚀剂在冷轧钢表面的吸附符合Langmuir吸附等温式,其吸附是自发、物理吸附过程。同步热分析还说明了该缓蚀剂易稳定吸附在冷轧钢表面。     

PASAT performance and the pattern of uptake of 99mTc-exametazime in brain estimated with single photon emission tomography

The effect of the paced auditory serial addition test (PASAT) on the regional uptake of 99mTc-exametazime was determined by single photon emission computed tomography. Twenty insulin-treated diabetic outpatients were scanned at rest and during the performance of the PASAT task using split-dose injection of tracer. When resting and activation scans were compared there were significant decreases in tracer uptake in the right anterior cingulate and left posterior cingulate areas during PASAT activation. The findings are compared with previous studies which had implicated the anterior cingulate area in the mechanisms of attention in humans and other animals. The potentially confounding role of anxiety during attentional tasks is discussed.     

Synergistic cooperation between phorbol ester and IFN-gamma for induction of nitric oxide synthesis in murine peritoneal macrophages

The role of protein kinase C (PKC) in the induction of nitric oxide (NO) synthesis in murine peritoneal macrophages was examined. Phorbol ester, a PKC activator, had no effect on NO synthesis by itself, whereas IFN-gamma alone had modest activity. When phorbol ester was used in combination with IFN-gamma, there was a marked cooperative induction of NO synthesis in a dose-dependent manner. This increase in NO synthesis was reflected as increased amount of inducible NO synthase (iNOS) mRNA, as determined by Northern blotting. The optimal effect of phorbol ester was shown at 6 h after treatment with IFN-gamma. Phorbol ester also induced the release of NO to the incubation medium by bacillus Calmette-Guerin-infected peritoneal macrophages. Prolonged incubation of cells with phorbol ester, which down-regulates PKC activity, abolished the synergistic cooperative effect on NO production with IFN-gamma. In addition, such PKC inhibitors as staurosporin or polymyxin B reduced NO production induced by IFN-gamma plus phorbol ester. When the cells were treated with both actinomycin D and phorbol ester after IFN-gamma stimulation, more NO was produced and more iNOS mRNA was expressed than in the cells treated with actinomycin D alone. On the basis of these observations, we conclude that PKC might not be directly involved in the expression of NO synthase, but, instead, might be involved in the stabilization of the iNOS mRNA already expressed by the treatment of IFN-gamma.     

Allergic contact dermatitis to quinones in Paphiopedilum haynaldianum (Orchidaceae)

An eczematous eruption developed on the hands and forearms of a 68-year-old man after frequent contact with homebred specimens of the lady slipper Paphiopedilum haynaldianum. Patch tests with leaves, petals, and stems, as well as with two quinones isolated from the plant by thin-layer chromatography, gave strongly positive reactions. The results demonstrated that the recurrent skin lesions were the expression of an allergic contact dermatitis due to the quinoid constitutnets, which are the main contact allergens in this orchid species.     

Acute cocaine results in rapid rises in intracellular free calcium concentration in canine cerebral vascular smooth muscle cells: possible relation to etiology of stroke

We report the outcome of 177 consecutive primary Charnley total hip arthroplasties inserted with Boneloc cement between November 1991 and November 1993. There were 107 women and 70 men. The mean age at the time of the operation was 71 years. 11 patients (13 hips) died during the follow-up period and 3 patients were too weak to attend a follow-up examination. Of the 161 remaining hips, 4 had been revised because of deep infection. The mean follow-up time for the remaining 157 hips was 2 (0.5-3) years. 24 hips had been revised and 6 are waiting for revision because of stem loosening. Of the remaining 127 hips, 72 showed radiographic signs of stem loosening and 2 hips were probably loose. Osteolysis was seen around the femoral component in 56 hips.     

Measures of postural steadiness: differences between healthy young and elderly adults

Measures of postural steadiness are used to characterize the dynamics of the postural control system associated with maintaining balance during quiet standing. The objective of this study was to evaluate the relative sensitivity of center-of-pressure (COP)-based measures to changes in postural steadiness related to age. A variety of time and frequency domain measures of postural steadiness were compared between a group of twenty healthy young adults (21-35 years) and a group of twenty healthy elderly adults (66-70 years) under both eyes-open and eyes-closed conditions. The measures that identified differences between the eyes-open and eyes-closed conditions in the young adult group were different than those that identified differences between the eye conditions in the elderly adult group. Mean velocity of the COP was the only measure that identified age-related changes in both eye conditions, and differences between eye conditions in both groups. The results of this study will be useful to researchers and clinicians using COP-based measures to evaluate postural steadiness.     

Legal framework of postgraduate nursing education in spain

Being part of the first report of the SEEIUC Forum on the training of nurses in critical care units, this article shows the different postgraduation training paths which Spanish legislation establishes. The "Titulos Oficiales de Especialización Profesional" ("Official Degrees on Professional Specialization") settle the seven nursing specialties regulated by the Decreto 992/1987. Following a second path, "Titulos de Postgraduado no Oficiales" ("Non-official postgraduation degrees"), every University acknowledged by the LRU and creating them as their Own Degrees, may organize Master courses, University experts, University specialists and Postgraduation university degrees, according to their autonomy. So that this autonomous offer is as homogeneous as possible, there is an interuniversity agreement which encompasses 24 national universities and gathers the general criteria for the academic organization of such courses. The report is completed by an analysis of the training offer for critical care nursing, developed during the 1995/1996 course in Spain.