Transmission electron microscopy study of a dental gallium alloy

Analytical transmission electron microscopy (TEM) studies of a dental gallium alloy have been carried out. This commercial Ga alloy was made by triturating a Ag-Sn-Cu-rich alloy powder with a liquid Ga alloy containing Ga, In and Sn. Ga alloys are of increasing interest as an alternative to amalgam. The dental material studied in the present work was found to be a composite consisting of remaining, undissolved particles from the Ag-based alloy powder in a matrix of reaction products with the liquid Ga alloy. The phases in the matrix and the remaining Ag-based alloy particles have been identified by electron diffraction, high resolution electron microscopy and energy dispersive X-ray spectroscopy. the following phases were identified: orthorhombic Ag₃Sn, cubic -Cu₉Ga₄, cubic Ag₉In₄, tetragonal -Sn and hexagonal Ag₂Ga. In addition to these well-known phases Ga-rich regions of Cu-Ga were observed consisting of an intergrowth of the tetragonal CuGa₂ and one of the cubic -Cu₉Ga₄ phases.     

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.     

Biochemical markers in acute myocardial infarct

Exact and early diagnosis of acute myocardial infarction is essential for the subsequent routine management of this frequent cardiovascular disease. At present, the clinical biochemistry possesses a set of more or less cardiospecific protein markers for early detection of myocardial ischemic damage. After the admission of patient to the hospital, serial estimations of rather non-specific enzyme activities (creatine kinase, its MB-izoenzyme, lactate dehydrogenase, hydroxybutyrate dehydrogenase) are currently used for the detection of acute myocardial infarction and for the further monitoring of the patient and managing his therapy. In the past decade, many cardiospecific biochemical markers were discovered and gradually introduced into the routine clinical practice. The most perspective markers are some molecules of contractile proteins of heart myofibrils (troponins, myosin chains) as well as "rediscovered" myoglobin. The aim of this review article is to inform about the commonly used, as well as about the new biochemical markers, to discuss some problems of diagnostic strategy in the early and exact detection of ischemic myocardial damage and to attract attention to the difficulties. However its disadvantage resides in its presence in both myocardium and skeletal muscles which arise when the diagnosis of acute myocardial infarction is prematurely excluded from consideration and such patients are discharged too soon from hospital. (Fig. 1, Tab. 1, Ref. 72.)     

Structural organization of the major autolysin from Streptococcus pneumoniae

LytA amidase is the best known bacterial autolysin. It breaks down the N-acetylmuramoyl-L-alanine bonds in the peptidoglycan backbone of Streptococcus pneumoniae and requires the presence of choline residues in the cell-wall teichoic acids for activity. Genetic experiments have supported the hypothesis that its 36-kDa chain has evolved by the fusion of two independent modules: the NH2-terminal module, responsible for the catalytic activity, and the COOH-terminal module, involved in the attachment to the cell wall. The structural organization of LytA amidase and of its isolated COOH-terminal module (C-LytA) and the variations induced by choline binding have been examined by differential scanning calorimetry and analytical ultracentrifugation. Deconvolution of calorimetric curves have revealed a folding of the polypeptide chain in several independent or quasi-independent cooperative domains. Elementary transitions in C-LytA are close but not identical to those assigned to the COOH-terminal module in the complete amidase, particularly in the absence of choline. These results indicate that the NH2-terminal region of the protein is important for attaining the native tertiary fold of the COOH terminus. Analytical ultracentrifugation studies have shown that LytA exhibits a monomer <--> dimer association equilibrium, through the COOH-terminal part of the molecule. Dimerization is regulated by choline interaction and involves the preferential binding of two molecules of choline per dimer. Sedimentation velocity experiments give frictional ratios of 1.1 for C-LytA monomer and 1.4 for C-LytA and LytA dimers; values that deviated from that of globular rigid particles. When considered together, present results give evidence that LytA amidase might be described as an elongated molecule consisting of at least four domains per subunit (two per module) designated here in as N1, N2, C1, and C2. Intersubunit cooperative interactions through the C2 domain in LytA dimer occur under all experimental conditions, while C-LytA requires the saturation of low affinity choline binding sites. The relevance of the structural features deduced here for LytA amidase is examined in connection with its biological function.     

Severe facial clefting, limbic dermoid, hypoplasia of the corpus callosum, and multiple skin appendages: severe frontofacionasal "dysplasia" or newly recognised syndrome?

We report on a child with severe midline facial cleft, bilateral cleft lip and palate, telecanthus, S-shaped palpebral fissures, limbic dermoid, midface hypoplasia, hypoplastic corpus callosum, and multiple skin appendages. This case may be an example of severe frontofacionasal "dysplasia" or a newly recognised syndrome.     

Combination of the vertical and periareolar mammaplasty

Two female and three male patients with acquired "tufted angioma" are presented. The age of these patients ranged from 10 to 62 years. Two lesions were sited in the head and neck region, two in the upper extremities, and one on the trunk. Clinically, the angiomatous lesions appeared as elevated plaques, flat lesions with papular and macular areas, or erythematous plaques with small nodules. In four cases a biopsy was done, and in one case the tumour was excised. Histologically, the neoplasms were characterized by irregularly distributed vascular tufts in the dermis, and, in one case, in the upper subcutis. The vascular tufts were composed of plump endothelial cells and spindle-shaped pericytes surrounded by crescent-shaped vascular spaces. The positive staining for CD 31 and for CD 34 and alpha-smooth muscle actin, and the negative staining of endothelial cells for factor VIII underline both the existence of two cellular components in tufted angioma and the immaturity of endothelial cells. Evidence of regular mitotic figures in two cases and increased proliferative activity in three out of four cases tested, emphasize the neoplastic nature of slowly growing tufted angioma. Benign tufted angioma is a distinct entity in the spectrum of capillary haemangiomas and must be distinguished from other vascular neoplasms.     

Influence of serotonergic neurons and of pineal gland on the development of the neonatal androgen sterilization syndrome in the rat

The effect of the removal of pineal gland, performed in adult age or during perinatal life, was investigated in the neonatal androgen sterility (NA-CEA) syndrome, in combination with drugs acting on serotonergic neurons. Perinatal pinealectomy (Px) was more potent in preventing the development of NA-CEA state than Px performed in the adult age. These data indicate that the masculinized hypothalamus becomes less sensitive to pineal influences during the lifespan. Effect of Px was potentiated by drugs increasing the central serotonergic tone. The results lead to the assumption that pineal hormones are influential on the maturation of serotonergic neurons, which might interfere with the sterilizing property of neonatal androgen treatment during the "critical" period of sexual differentiation.     

Monoclonal antibodies against potato virus A -- immunoblot analysis

Monoclonal antibodies (MoAbs) against potato virus A (PVA) were examined in their reactivity with PVA and its denatured capsid protein (PVA-CP) bound to the nitrocellulose membrane. Five MoAbs reacted with native PVA, three of them also with PVA-CP. One MoAb gave no reaction in dot-blot test. In polyacrylamide electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE) PVA-CP migrated as two major bands. In immunoblot analysis, two MoAbs reacted only with the slower band, one only with the faster one. We presume that those bands do not correspond to the intact CP but they do to truncated N- and C-terminal CP molecules, respectively, and that the corresponding epitopes reacting with MoAbs are localized near to both termini of CP molecules. After mild trypsinolysis of PVA particles no MoAb reacted with resulting "core" CP.     

The menopause: women's psychology and health care

Menopause has often been described as a time of loss and decay in the lay and medical literature. The present research aims at defining women's perception of themselves and their health care needs in this period of life. Through a community-based sample of women, participative assessments were performed and their conclusions contrasted with the opinions of male and female gynecologists. Though both groups coincided concerning the relevance of loneliness, partnership, beauty and the "empty nest" syndrome, several items showed a marked difference between both groups. Gynecologists tended to perceive women as much more striving for an active sex-life, depressed, lacking projects for the future and worried about their health care than they actually were. Women, instead, stressed the relevance of menopause as a life crisis laden with opportunities for self-accomplishment and positive changes in life-style towards greater autonomy.     

Parallel algorithms for image enhancement and segmentation by region growing, with an experimental study

This paper presents efficient and portable implementations of a powerful image enhancement process, the Symmetric Neighborhood Filter (SNF), and an image segmentation technique that makes use of the SNF and a variant of the conventional connected components algorithm which we call -Connected Components. We use efficient techniques for distributing and coalescing data as well as efficient combinations of task and data parallelism. The image segmentation algorithm makes use of an efficient connected components algorithm based on a novel approach for parallel merging. The algorithms have been coded in Split-C and run on a variety of platforms, including the Thinking Machines CM-5, IBM SP-1 and SP-2, Cray Research T3D, Meiko Scientific CS-2, Intel Paragon, and workstation clusters. Our experimental results are consistent with the theoretical analysis (and provide the best known execution times for segmentation, even when compared with machine-specific implementations). Our test data include difficult images from the Landsat Thematic Mapper (TM) satellite data.Also affiliated with the Department of Electrical Engineering.Also affiliated with the Department of Computer Science and the Center for Automation Research.