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Biomedical subjects

J B Thomas

Publications and source records attributed to J B Thomas.

At least 73 records · Page 4Linked to original sources
PubMed1993

The Drosophila bendless gene encodes a neural protein related to ubiquitin-conjugating enzymes.

The bendless (ben) mutation of Drosophila alters synaptic connectivity between a subset of CNS neurons. Here, we show that ben also causes morphological abnormalities within the visual system, suggesting that ben functions in a number of different developmental processes. We show that the ben gene encodes a protein which is closely related to ubiquitin-conjugating enzymes and that a missense mutation in the highly conserved active site region is associated with the ben mutation. High levels of ben expression are restricted to the nervous system during development. These results suggest a role for ubiquitin-mediated protein modification in nervous system development, including, but not exclusive to, the regulation of synaptic connectivity.

Amino Acid Sequence↗
PubMed1993

Single-minded regulation of genes in the embryonic midline of the Drosophila central nervous system.

Proper development of the midline cells within the Drosophila central nervous system is controlled by the single-minded (sim) gene. The sim protein defines a new subclass of bHLH transcription factors and as such, is predicted to function as a transcriptional regulator of other genes important for midline development. Here we identify two potential targets of sim regulation: the sim gene itself, and the 47F gene, which is expressed specifically in the sim-expressing midline cells. Using a transgene containing sim regulatory sequences fused to beta-galactosidase, we show that the sim gene uses two distinct promoters with overlapping temporal specificities, and that expression from the late promoter is autoregulated by sim itself. By expressing sim protein in salivary gland nuclei using the heat-shock inducible Hsp70 gene promoter, we show that sim protein associates with the sim late promoter on polytene chromosomes. In addition, sim protein binds to a small number of additional chromosomal sites, among which are the sites of the 47F gene, and two other genes, Tl and cdi, whose expression also depend on sim function.

Animals↗
PubMed1993

Strategic sensemaking and organizational performance: linkages among scanning, interpretation, action, and outcomes.

This study investigated the strategic "sensemaking" processes of scanning, interpretation, and action and how those activities are linked to organizational performance. Using path analyses on data from 156 hospitals, we tested the direct and indirect effects among these sensemaking processes and performance outcomes and developed a model of their relationships. In a more general sense, the research represents an attempt to provide insight not only into relationships between cognition and action, but also into the links between those fundamental processes and organizational performance outcomes.

Adult↗
PubMed1992

Apterous is a Drosophila LIM domain gene required for the development of a subset of embryonic muscles.

The recently discovered LIM motif is found in a set of homeodomain-containing proteins thought to mediate the generation of particular cell types. Of the four LIM domain family members described to date, mec-3 and lin-11 determine cell lineages in C. elegans. Isl-1 and Xlim-1 may play similar roles in vertebrates. We have identified a Drosophila member of this class, the product of the apterous (ap) gene. During embryogenesis, ap is expressed in a small subset of fusing mesodermal precursors that give rise to 6 muscles in each abdominal hemisegment and in 5 neurons within each corresponding CNS hemisegment. Lack of ap function results in loss of ap-expressing muscles, while misexpression of ap using a heterologous promoter produces ectopic muscles.

Amino Acid Sequence↗
PubMed1992

Developing interorganizational relationships in the health sector: a multicase study.

Because of the wide diversity among health care organizations, interorganizational relationships (IORs) among them are difficult to manage. This article describes three case studies that, taken together, suggest that IOR performance is related to IOR development processes. Specifically, IOR performance is related to the way managers process information to manage uncertainty and ambiguity.

Chief Executive Officers, Hospital↗
PubMed1992

Cryptococcosis in seven horses.

The clinical, radiographic and post-mortem findings in 6 horses with cryptococcal pneumonia and one horse with an abdominal cryptococcal granuloma are described. In pulmonary cryptococcosis, the lesions were either diffuse and multiple, with bilateral lung involvement, or localised mainly to the dorsocaudal region of one lung. The cases of diffuse multiple cryptococcosis were thought to be associated with haematogenous spread of the fungus after gastrointestinal infection and dissemination from regional lymph nodes. The localised form of the disease was thought to have been associated with inhalation of cryptococci. In all cases of pulmonary cryptococcosis, encapsulated yeast-like organisms were demonstrated in Wright's-stained sediment of tracheal washes. In the horse with the abdominal granuloma, cryptococci were present in a fine needle aspirate sample. Isolates of Cryptococcus neoformans var gattii were recovered from 2 of the 5 horses in which cultures were attempted. In addition to a history of previous illness that may have predisposed to infection, most horses in this report had been in areas in which Eucalyptus camaldulensis, or the closely related E rudis, were growing. In humans, an epidemiological relationship between E camaldulensis and infection with C neoformans var gattii has been suggested. Cases of equine cryptococcosis carry a poor prognosis and treatment was not attempted in any of these cases.

Abdomen↗
PubMed1992

Aligning business and information technology domains: strategic planning in hospitals.

This article develops a framework for strategic information technology (IT) management in hospitals, termed the Strategic Alignment Model. This model is defined in terms of four domains--business strategy, IT strategy, organizational infrastructure, and IT infrastructure--each with its constituent components. The concept of strategic alignment is developed using two fundamental dimensions--strategic fit and integration. Different perspectives that hospitals use for aligning the various domains are discussed, and a prescriptive model of strategic IT planning is proposed.

Commerce↗
PubMed1991

Experimental copper and heliotrope intoxication in sheep: morphological changes.

Young Merino wethers were used to determine the effects of copper and heliotrope, fed together or separately, on the development of toxicity and the concentration of trace elements in the liver and kidney. In one experiment copper and heliotrope were given concurrently, in a second experiment heliotrope was fed for 12 weeks and copper administration commenced 8 weeks later. The 10 sheep fed heliotrope alone did not show signs of clinical illness but one died and was found to have severe liver damage. Eleven sheep were given copper alone and three developed the clinical signs and lesions of haemolysis. Fourteen sheep were given copper and heliotrope and 13 became ill. Of these, three developed haemolysis, eight became jaundiced and two became weak without developing jaundice. The concentrations of copper in the livers of control and heliotrope-treated sheep, were comparable. In the animals given copper alone, the concentration of copper in the liver was twice as high as that in controls and in those given heliotrope and copper, it was three times as high as in the liver of control sheep. Feeding heliotrope alone induced the histological changes of pyrrolizidine alkaloid toxicity in the liver, but this was not associated with an excessive accumulation of copper or the development of clinical illness. However, it did predispose the animals to the effects of a second toxin since giving heliotrope and copper concurrently, or giving copper subsequent to feeding heliotrope, markedly enhanced the toxicity of the two substances and caused an excessive accumulation of copper in the liver.

Animals↗
PubMed1991

The thinking hospital.

Explore the source record for details and available documents.

Decision Making, Organizational↗
PubMed1991

Hospitals as interpretation systems.

In this study of 162 hospitals, it was found that the chief executive officer's (CEO's) interpretation of strategic issues is related to the existing hospital strategy and the hospital's information processing structure. Strategy was related to interpretation in terms of the extent to which a given strategic issue was perceived as controllable or uncontrollable. Structure was related to the extent to which an issue was defined as positive or negative, was labeled as controllable or uncontrollable, and was perceived as leading to a gain or a loss. Together, strategy and structure accounted for a significant part of the variance in CEO interpretations of strategic events. The theoretical and managerial implications of these findings are discussed.

Decision Making, Organizational↗
PubMed1990

Molecular genetics of neuronal development in the Drosophila embryo.

Making a functional nervous system involves the production of specific types of neurons in characteristic locations and their ability to find and synapse with appropriate target cells. By capitalizing on the advanced genetics and molecular biology of Drosophila, a rapidly growing number of genes have been identified that control these events. Studies of the expression and function of these genes in single, uniquely identified cells is possible because of the relative simplicity of the Drosophila embryonic nervous system. A class of neurogenic genes, including N, Dl, and E(spl), controls the emergence of the entire neuronal precursor population, whereas some of the segmentation genes, such as ftz and eve, control the fates of individual neurons. Later in development, genes encoding cell-surface molecules, called fasciclins, may be involved in the ability of growing neurons to recognize and elongate axons along specific pathways to reach their synaptic targets.

Animals↗
PubMed1990

Generalised protothecosis in a collie dog.

A case of generalised protothecosis in a Collie dog is discussed. A long-standing history of severe colitis was the major clinical sign. Dissemination to many organs was confirmed histologically. Possible pathogenesis is discussed along with a review of the literature. The possibility of a breed disposition in Collie dogs is discussed. The organisms are ubiquitous in the environment and generalised disease suggests the possibility of immune competence.

Animals↗
PubMed1990

Immunohistochemical demonstration of canine distemper virus antigen as an aid in the diagnosis of canine distemper encephalomyelitis.

Brain tissue from 33 dogs with non-suppurative encephalitis was examined for evidence of canine distemper virus (CDV) encephalitis. Sections were examined for lesions, inclusion bodies, syncytial cells and CDV antigen using a double bridge unlabelled antibody enzyme technique. Histopathological lesions considered to be typical of granulomatous meningoencephalomyelitis were found in seven dogs. They all lacked inclusion bodies, syncytial cells and CDV antigen. The remaining 26 dogs all had histopathological lesions typical of CDV encephalitis. Inclusion bodies were found in 24 dogs, four of which also had syncytial cells and CDV antigen was detected immunocytochemically in 25. One dog had no inclusion bodies or syncytial cells and was immunohistochemically negative. Syncytial cells have been found to be of limited diagnostic value for the diagnosis of CDV encephalitis. While inclusion bodies proved to be a good diagnostic criterion for the confirmation of CDV infection, the immunohistochemical demonstration of CDV antigen proved to be superior. CDV antigen was more prevalent than inclusion bodies in tissue sections and much more easily detectable.

Animals↗