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Biomedical subjects

J Hamilton

Publications and source records attributed to J Hamilton.

At least 19 recordsLinked to original sources
PubMed1992

A survey examining nurses' knowledge of pain control.

Three hundred and eighteen (318) nursing staff members at an acute care teaching hospital in Montreal, Canada, were surveyed to identify their knowledge of pain assessment and management. Two pain instruments were combined and adapted for use. The final instrument consisted primarily of true/false responses and took about 10 min to complete. The mean score was 63.9%. Overall results indicated that nurses lacked knowledge and understanding of opioid addiction, equivalent dosing, properties of opioids, and differences in acute and chronic pain. No statistically significant differences were found in the scores by level of educational preparation or by years of experience. Presentation of the results unit by unit demonstrated that the instrument is suitable as an educational tool as well as an effective strategy to introduce nursing staff to nursing research.

Adult↗
PubMed1992

Distribution of cholecystokinin forms in intestinal secretory granule subtypes.

Peptides and proteins destined to be released in response to stimuli are found in the regulated secretory pathway. Substances in this pathway are packaged into secretory granules, wherein they are often rendered osmotically inactive by complexing to an oppositely charged molecule. The complexing mechanism employed by members of the cholecystokinin (CCK) peptide family is unknown, but the heterogenous charges of CCK peptides makes it possible that different CCK peptides have different abilities to form intragranular complexes. If the number of osmotically active intragranular CCK peptides varies, corresponding variations in secretory granule density should result, and when intestinal CCK secretory granules were purified on isotonic density gradients, four granule peaks were observed. Granules containing greater proportions of short CCK forms tended to have the lowest buoyant densities, suggesting that they contain a greater number of osmotically active molecules than granules of lower density and that short or all intragranular CCK forms are osmotically active. CCK secretory granules also contained novel CCK forms; in addition to previously characterized forms, granules contained a CCK form that appears to be CCK-6 and a form that could arise from cleavage of CCK-58 at position 4, 10, or 12. Because intragranular enzymes are responsible for peptide posttranslational processing, the intragranular CCK forms observed in the present study are likely to be authentic CCK-processing products. Finally, CCK sorting in intestine apparently differs from that in a rat medullary thyroid carcinoma cell line, in which CCK-22 and CCK-33 are not found in the regulated secretory pathway.

Animals↗
PubMed1992

The effect of cytokines on the expression of MHC antigens and ICAM-1 by normal and transformed synoviocytes.

We report the expression on synovial cells of cell surface molecules known to be involved in T cell activation by antigen presenting cells. Normal human synovial fibroblasts and a human synovial cell line transformed with the SV40 large T antigen were used for in vitro stimulation studies with recombinant cytokines. We demonstrate an increase in MHC-A, B, C expression in normal synovial cells in response to recombinant interferon gamma (r gamma IFN), tumour necrosis factor alpha and beta (rTNF alpha and beta) and interleukin-1 (rIL-1 alpha). Intercellular adhesion molecular-1 (ICAM-1) expression was increased in parallel with MHC Class I. The combination of r gamma IFN and rTNF alpha was additive in its effect on ICAM-1 expression. Northern blot analysis suggests that ICAM-1 expression in synovial cells is controlled at the level of transcription. In contrast, MHC Class II (HLA-DR) was only significantly induced by r gamma IFN. Other stimuli including interleukin-4 (IL-4), interleukin 6 (IL-6), granulocyte macrophage colony stimulating factor (GM-CSF) and prostaglandin E2 (PGE2) did not affect the expression of ICAM-1 or MHC Class I and II. Leucocyte function antigen 3 (LFA-3) expression was not affected by any of the stimuli tested. Immunoperoxidase staining of rheumatoid synovial tissue confirmed enhanced in vivo expression of ICAM-1 in rheumatoid arthritis. These changes are discussed in the context of T cell activation in inflammatory arthritis.

Arthritis, Rheumatoid↗
PubMed1991

Preparation and crystallization of human transthyretin (prealbumin) variants.

Naturally occurring variants of human serum transthyretin (prealbumin) have been prepared by recombinant DNA methods and crystallized from ammonium sulfate solutions to give crystals suitable for x-ray crystallographic analysis. Included are variants which are known to be associated with familial amyloidotic polyneuropathy. Dyes which have been used as histochemical stains to identify amyloid tissue deposits: Congo Red, Methylene Blue and Bromophenol Blue, have been co-crystallized with the transthyretin variants. Congo Red was found to be very selective while Methylene Blue actually assisted in the formation of crystals. All crystal forms which were examined were isomorphous to the structure of normal transthyretin.

Base Sequence↗
PubMed1991

On the relationship between self-focused attention and psychological disorder: a critical reappraisal.

A recent review of the literature on the role of self-focused attention in psychological dysfunction (Ingram, 1990) is critically examined. This article (a) reexamines the evidence relevant to Ingram's proposal that self-awareness is a nonspecific factor involved in virtually all forms of psychopathology and argues that this conclusion is not warranted by the existing evidence; (b) takes issue with his premise that the fact that self-awareness is associated with a variety of psychological dysfunctions poses a conceptual dilemma; (c) corrects several important inaccuracies and mischaracterizations in his presentation of Carver and Scheier's (1981) cybernetic control theory and Pyszczynski and Greenberg's (1987) self-regulatory perseveration theory; and (d) critiques the "self-absorption" model that he proposed as an alternative to extant theories and concludes that this conceptualization does not add to the understanding of either self-awareness processes or psychopathology.

Attention↗
PubMed1991

Equine neural angiostrongylosis.

Verminous encephalomyelitis due to Angiostrongylus cantonensis larvae was diagnosed in 2 foals at necropsy. The principal clinical feature was tetraparesis, although history and neurological examination revealed progressive and multifocal neurological disease. At presentation, a tentative diagnosis of parasitic larval migration involving the central nervous system (CNS), presumably due to Strongylus vulgaris, was proposed. Dissection of the spinal cord in one case resulted in recovery of intact larvae of both sexes of A. cantonensis. In both foals, histopathology of the brain and spinal cord revealed nematode sections which were consistent with A. cantonensis larvae.

Angiostrongylus↗
PubMed1991

Measuring the efficiency of an artificial lung: 1. Carbon dioxide transfer.

The performance of a hollow fibre artificial lung ('Capiox E') was analysed by measurement of the 'parallel deadspace' of the device under varying conditions in 21 patients. The efficiency with which carbon dioxide was exchanged was determined by the time available for equilibration between the blood and gas phases. When this equilibration coefficient was less than 12 seconds per litre of blood flow per litre of gas flow, there was a marked reduction in the efficiency of gas exchange. Under certain conditions, the 'counter-current' design of the device apparently permitted the clearance of carbon dioxide at a partial pressure greater than that which was found in the mixed venous blood. This anomalous behaviour may represent in vivo confirmation of the Haldane effect.

Adult↗
PubMed1990

The isolation and partial characterization of bovine parathyroid secretory granules.

We have developed a procedure which allows the isolation of secretion granules from fresh parathyroid glands. Following collagenase digestion of the tissue, the cells were broken with osmotic shock and a crude granule/mitochondrial pellet was obtained by differential centrifugation. Before loading this fraction onto a metrizamide density gradient it was subjected to brief sonication to disrupt the mitochondria. This procedure was necessary in order to achieve separation of the granules from the mitochondria during ultracentrifugation of the gradient. When the fractionated gradient was analysed for PTH by radioimmunoassay, three bands containing parathyroid hormone were found, at densities of 1.0, 1.05 and 1.18. Upon electron microscopic examination of the gradient fractions, granules were found only in those fractions containing hormone. A typical granule appearance was observed for two of the populations, but the third population (density 1.18), consisted of granules without membranes and which appeared less electron dense than those of populations 1 (density of 1.0) and 2 (density of 1.05). Moreover, the lack of a limiting membrane imparted a fuzzy appearance to the population 3 granules. When fresh tissue sections were examined as control samples, granules with and without membranes were also observed. Standard marker enzyme assays further confirmed that populations 2 and 3 were relatively free of other cellular contaminants, but population 1 contained endoplasmic reticulum and lysosomal material. Because the number of granules contained in this population is very small, we have not been successful in achieving further purification of population 1. Based on radioimmunoassay of extracts of each granule population, PTH was concentrated in population 3, while the other two contained lesser amounts. Interestingly, results obtained with a radioimmunoassay for SP-1 revealed a striking difference in the distribution of SP-1 in the three granule populations. This protein, which is also secreted by the parathyroid gland, was concentrated in population 1 and 2. Only very low levels were found in population 3. Thus, the two major secretory products are localized in different granule populations. The isolated granules were stable to pH changes, cycles of freeze/thaw and sonication. The yields of PTH extracted from each of the granule populations by freezing and thawing in buffer or by Triton containing solutions were low. PTH was completely extracted from each population only by using 8 M urea in HCl. Lower concentrations of urea were less effective. These results indicate that the molecular architecture of the granules is highly resistant to disruption.

Animals↗
PubMed1979

The use of the diving reflex to terminate supraventricular tachycardia in a 2-week-old infant.

The use of the diving reflex to terminate a case of paroxysmal supraventricular tachycardia (PST) is described in a 2-week-old infant who presented in severe congestive heart failure with supraventricular tachycardia at a rate of 300. The infant's face was placed in a basin of ice water at 5 degrees C. for 5 seconds with manual occlusion of the infant's nostrils to prevent aspiration. The PST converted to a sinus rhythm of 120 within 3 seconds of facial immersion. The physiology of the diving reflex is reviewed and the uses and hazards of this reflex in terminating attacks of PST in infants is discussed.

Diving↗
PubMed1979

Adrenergic- and cyclic nucleotide-induced glycerol release from brown adipocytes.

Previous work has shown that although both alpha- and beta-agonists stimulate brown fat heat production, the beta agonist is quantitatively more effective. The finding in the present study that isoproterenol, a beta-agonist, significantly stimulates net glycerol release from isolated hamster brown adipocytes while the alpha-agonist, phenylephrine does not, may account (at least in part) for the differential thermogenic response to the two types of agents. The present study also compared lipolytic responses to AMP, cAMP, cGMP and theophylline, with the results indicating a greater rate of net glycerol release being induced by AMP and by cAMP than by theophylline or cGMP plus theophylline.

Adenosine Monophosphate↗
PubMed1979

Successful coping styles in professional women.

This paper describes the experiences of seven women mental health professionals who met in a leaderless group over a period of a year and a half. There is a discussion of the conflicts for women in four major areas--competition, dependency needs, economic success and the search for role models, and the suggestion of possible successful resolutions in these conflict areas. The resolutions are a result of individual experiences and discussions in the group.

Adaptation, Psychological↗
PubMed1978

Type B hepatitis after needle-stick exposure: prevention with hepatitis B immune globulin. Final report of the Veterans Administration Cooperative Study.

Hepatitis B immune globulin (HBIG) and immune serum globulin (ISG) were examined in a randomized, double-blind trial to assess their relative efficacies in preventing type B hepatitis after needle-stick exposure to hepatitis B surface antigen (HBsAG)-positive donors. Clinical hepatitis developed in 1.4% of HBIG and in 5.9% of ISG recipients (P = 0.016), and seroconversion (anti-HBs) occurred in 5.6% and 20.7% of them respectively (P less than 0.001). Mild and transient side-effects were noted in 3.0% of ISG and in 3.2% of HBIG recipients. Available donor sera were examined for DNA polymerase (DNAP) and e antigen and antibody (HBeAg; anti-HBE). Both DNAP and HBeAg showed a highly statistically significant correlation with the infectivity of HBsAg-positive donors. Hepatitis B immune globulin remained significantly superior to ISG in preventing type B hepatitis even when the analysis was confined to these two high-risk subgroups. The efficacy of ISG in preventing type B hepatitis cannot be ascertained because a true placebo group was not included.

Adolescent↗