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Biomedical subjects

J Stuart

Publications and source records attributed to J Stuart.

At least 91 records · Page 5Linked to original sources
PubMed1991

Checking of unit dose cassettes by pharmacy technicians at three Minnesota hospitals.

A pilot project in which pharmacy technicians were trained to check unit dose cassettes filled by other technicians is described. With the approval of the state board of pharmacy, the Minnesota Society of Hospital Pharmacists (MSHP) conducted the nine-month project in three hospitals with different types of unit dose drug distribution systems. Twenty-seven technicians underwent didactic and practical training and were then validated as checkers if they scored 99.8% accuracy in checking carts into which errors had been deliberately introduced by the pharmacist auditor. The performance of validated technicians was audited monthly, and failed audits had to be repeated. Participating technicians did not check the preparation of first doses or extemporaneously prepared doses. In 100,000 doses audited, 60 errors by the validated checkers were identified. Of six technicians who failed a monthly audit, five passed a repeat audit. Pharmacists at the participating hospitals documented time they spent on clinical activities that would have been spent checking cassettes. In December 1990 a one-year extension of the project, expanded to 10 hospitals, began. With strict quality control measures, specially selected and trained pharmacy technicians performed unit dose cassette checking with an accuracy of at least 99.94%.

Humans↗
PubMed1991

Rheological action of drugs that prevent erythrocyte dehydration.

The water content of the human erythrocyte is a major determinant of its cytoplasmic viscosity and thus deformability. Loss of cell water may be either primary or secondary to loss of erythrocyte cations (K+). Several existing drugs (cetiedil citrate, pentoxifylline and piracetam) have recently been shown to inhibit K+ loss from erythrocytes and thus have the potential to prevent erythrocyte dehydration. Further studies of cation flux pathways in the erythrocyte membrane are of importance for the development of new drugs that maintain cell hydration.

Azepines↗
PubMed1990

Red cell deformability and haematological disorders.

Blood rheology is the science of the flow and deformation of blood. Clinically, blood rheology is important because circulatory resistance has two major components, vascular and rheological. In large vessels, blood rheology should be considered in terms of bulk flow, the viscosity of blood depending mainly on red cell concentration and plasma viscosity and, to a lesser extent, on red cell deformability and aggregation. In the microcirculation, where cells must deform to pass through narrow capillaries, cellular rheology (i.e. the deformability of individual cells) is a major determinant of resistance to flow. This ability to deform is also a determinant of the cell's survival time in the circulation. The deformability of the red cell is essentially linked to its structure (i.e. its cellular geometry, membrane properties and cytoplasmic viscosity); thus structural abnormalities, as found in some haematological disorders, can be expected to affect blood flow in the microcirculation and/or red cell lifespan. Blood rheology is a relatively new discipline as applied to the practice of haematology. In 1985 the International Committee for Standardization in Haematology (ICSH) established an Expert Panel on Blood Rheology which has subsequently issued guidelines on the measurement of blood viscosity and erythrocyte deformability and on tests such as erythrocyte sedimentation rate and plasma viscosity that are used to monitor the acute phase response in inflammatory disease. Rheological methods now have sufficiently good sensitivity and specificity for their application to a wide variety of clinical disorders. This review illustrates their potential application to haematological disorders that cause abnormal deformability of red cells.

Erythrocyte Deformability↗
PubMed1990

Object relations in borderlines, depressives, and normals: an examination of human responses on the Rorschach.

Recently, researchers and clinicians have become increasingly interested in diagnostic distinctions between borderline and mood disorders. Object relations theory provides a useful framework for the comparison of these two overlapping diagnostic categories. In our study, a measure of object relations as represented on the Rorschach, developed by Blatt, Brenneis, Schimeck, and Glick (1976), was applied to data produced by borderline and depressive inpatients and by normal comparison subjects. Portions of the Blatt measure that tap the subject's experience of human action and interaction distinguish among the three diagnostic groups. Specifically, borderlines tend to understand human action as more highly motivated and human interaction as more malevolent in nature than do either depressive or normals. The data indicate that borderlines experience the object-relational world in a way that is fundamentally different from the way normals and depressives perceive it. Implications are discussed for theories of borderline object relations.

Adult↗
PubMed1990

Postural consistency in skilled archers.

The consistency of an archer's postural set at the moment of loose (arrow release) is commonly perceived to be an important determinant of success. The coach seeks, among other things, to provide the archer with information about postural consistency, details of which he acquires by eye or occasionally by video-recordings. The gains that might be achieved from more precise information are examined here. Nine skilled archers, classified into either skilled or elite groups according to their officially computed handicap, were continuously monitored and measured with a three-dimensional co-ordinate analyser (Charnwood Dynamics Coda-3 Scanner) while shooting two ends (series) of three arrows each. Considerable variability was observed in the precision with which the positions of head, elbow and bow at the moment of loose were replicated by archers of similar levels of skill. These results are interpreted to suggest that precise postural consistency may not be the primary feature distinguishing between the performance of archers at the higher skill levels.

Analysis of Variance↗
PubMed1990

Technological advances in blood rheology.

The science of blood rheology (study of the flow and deformability of blood) is of increasing practical importance to the investigation of blood disorders. In diagnostic laboratories, rheological tests such as the erythrocyte sedimentation rate, zeta sedimentation ratio, and plasma viscosity are used to monitor patients with an acute-phase response of greater than 24 h duration. In sickle-cell anemia, new methods for measuring erythrocyte deformability can be used to investigate the pathogenesis of vaso-occlusion, to test potential anti-sickling drugs, and to monitor drug efficacy in clinical trials. Genetic defects in the structure of the red cell membrane can have rheological consequences, monitoring of which may be useful for diagnosis. Rheological analysis of red cells infected by Plasmodium falciparum has indicated that their abnormal flow behavior may be an important pathological factor in malaria. Finally, the flow behavior of white blood cells, particularly neutrophils, is also important, as these cells, once activated, have the potential to occlude microvessels. The authors have reviewed the laboratory methodology and clinical applications that have led to recent advances in these aspects of blood rheology.

Acute-Phase Reaction↗
PubMed1989

Efficacy of tests used to monitor rheumatoid arthritis.

The relative efficacy of clinical and laboratory tests used to monitor disease activity in rheumatoid arthritis was determined by consensus analysis in a study of 21 patients treated for 6 months. Erythrocyte sedimentation rate (ESR), which is influenced by the anaemia of chronic disease and by variation in the blood concentration of acute-phase proteins, was the most effective single test. ESR was a better guide to disease severity than measurement of plasma viscosity, serum C-reactive protein, and serum orosomucoid--tests that reflect the blood concentration of acute-phase proteins only. Clinical tests performed poorly unless combined with laboratory data in a numerical index. Consensus analysis can be used to assess the efficacy of clinical and laboratory tests and to identify redundant tests.

Adult↗
PubMed1989

Pharmacological modification of oxygen affinity improves deformability of deoxygenated sickle erythrocytes: a possible therapeutic approach to sickle cell disease.

1. The formation of polymerized haemoglobin S in sickle cells is critically dependent on the concentration of deoxygenated haemoglobin so that compounds which increase the oxygen affinity of haemoglobin S are potential anti-sickling agents. 2. BW12C [5-(2-formyl-3-hydroxyphenoxy)pentanoic acid] and BWA589C [4-(2-formyl-3-hydroxyphenoxymethyl)benzoic acid] are aromatic benzaldehydes that cause a dose-dependent left-shift of the oxygen saturation curve of haemoglobin S by stabilization of its oxy-(R)-conformation. 3. A 5 micron pore filtration method, which is highly sensitive to polymerization of haemoglobin S, was used to demonstrate a significant improvement in the deformability of deoxygenated sickle erythrocytes at concentrations (0.75-1.5 mmol/l] of BW12C and BWA589C that are achievable in vivo. Both compounds may therefore be of value for the treatment of sickle cell disease. 4. Filtration of sickle cells through pores of 5 microns diameter is a sensitive technique for evaluating the rheological effects of potential anti-sickling compounds.

Anemia, Sickle Cell↗
PubMed1989

Bepridil protects sickle cells against the adverse rheological effects of cyclical deoxygenation.

Calcium influx into sickle cells, with consequential activation of the Ca2(+)-activated K+ efflux (Gardos) channel, is a potential cause of cellular dehydration and loss of deformability. Bepridil, a recently described inhibitor of the Gardos channel, was found at pharmacological concentration (1 mumol/l) to inhibit significantly (P less than 0.01) the loss of deformability when sickle cells were subjected to cycles of oxygenation-deoxygenation for 15 h at 37 degrees C. Bepridil also inhibited significantly (P less than 0.005) the formation of irreversibly sickled cells. Drugs that preserve the K+ and therefore water content of erythrocytes are of potential value for hydrotherapy of sickle cell disease.

Anemia, Sickle Cell↗
PubMed1989

Effect of polymerization tendency on haematological, rheological and clinical parameters in sickle cell anaemia.

The polymerization tendency of sickle haemoglobin was estimated as a function of oxygen saturation in 30 patients with homozygous sickle cell anaemia. The deformability of their erythrocytes was also measured, by initial-flow-rate filtration at 37 degrees C through pores of 5 microns diameter, and clinical severity was assessed using a visual analogue scale. By means of partial correlation analysis, it was found that correlations between haematological, rheological, and clinical parameters in sickle cell anaemia could be explained on the basis of an association of each variable with polymerization tendency. Patients with the greatest tendency to form polymer had the least deformable erythrocytes and perceived their disease to be more severe as judged by the visual analogue scale. Polymer formation also appeared to be a determinant of the number of dense cells which, in turn, determine haemolytic rate and erythrocyte deformability.

Anemia, Sickle Cell↗
PubMed1989

Erythrocyte heterogeneity in sickle cell disease: effect of deoxygenation on intracellular polymer formation and rheology of sub-populations.

Erythrocytes from 12 patients with homozygous sickle cell disease in the steady state were fractionated on a Percoll-Stractan density gradient. Erythrocyte deformability was measured by initial-flow-rate filtration through pores of 5 microns diameter and erythrocyte polymer content was calculated as a function of oxygen saturation. Density fractionated sub-populations of sickle cells showed distinct rheological characteristics, the filterability of dense cells being impaired by minimal oxygen desaturation with the apparent formation of little or no intracellular polymer. Lighter cell fractions required a greater degree of deoxygenation and polymer formation to impair deformability, although this occurred prior to morphological sickling. Dense cells therefore exert a disproportionate effect on blood rheology in sickle cell disease and are likely to have an adverse rheological effect in vivo at arterial oxygen tension.

Anemia, Sickle Cell↗
PubMed1989

Evaluation of sealed vacuum extraction method (Seditainer) for measurement of erythrocyte sedimentation rate.

A sealed vacuum extraction method (Seditainer) for determining the erythrocyte sedimentation rate (ESR) was compared with the standard Westergren ESR technique. The Seditainer method was particularly easy to use, showed acceptable precision, reduced the biohazard risk to laboratory staff and, on storage of sealed blood specimens for 24 hours at 4 degrees C, gave ESR values that had decreased by a mean of only 1.9% (95% CI + 0.2 to -4.0%). Seditainer tubes are shorter (100 mm) than Westergren tubes (200 mm) and this reduced test sensitivity at ESR values above 55 mm/first hour. After application of the manufacturer's correction formula to adjust for tube length there was improved correlation (n = 150, r = 0.936, p less than 0.001), but still considerable scatter, between the Seditainer and Westergren results. Seditainer ESR values above 55 mm/first hour should therefore be regarded as semiquantitative. This vacuum extraction method offers a simple and safe technique for measuring the ESR and specimens can be stored overnight at 4 degrees C.

Blood Sedimentation↗
PubMed1989

Acquired immunodeficiency syndrome.

A report entitled "Kaposi's Sarcoma and Pneumocytosis Carinii Pneumonia among homosexual men in New York City and California" in the MMWR in July 1981 alerted the world to the appearance of a completely new disease. The opportunistic infections and cancers occurring in these patients had previously only been seen in patients who were immunosuppressed. Homosexual men were the first as a major risk group to be identified. Others quickly followed. The pattern of occurrence clearly indicated an infectious agent as the likely cause, and within two years the virus had been identified in Europe and the USA. In Europe it was named Lymphadenopathy Associated Virus (LAV) by Montagnier its discover, and in the USA, Human T cell Lymphotrophic Virus III (HTLV III). It is now known as Human Immunodeficiency Virus (HIV).

Acquired Immunodeficiency Syndrome↗
PubMed1988

Adenine nucleotides stimulate oxidation-induced calcium efflux from sarcoplasmic reticulum vesicles.

Micromolar concentrations of copper (Cu2+) and cysteine induce rapid efflux of calcium from sarcoplasmic reticulum (SR) vesicles. This effect appears to be due to a Cu2+-catalyzed oxidation of the added cysteine to a critical sulfhydryl group on the release protein from sarcoplasmic reticulum (J. L. Trimm, G. Salama, and J. J. Abramson (1986) J. Biol. Chem. 261, 16092-16098). The data presented here indicate that adenine nucleotides synergistically stimulate copper/cysteine (oxidation)-induced calcium efflux from SR vesicles. The order of effectiveness in stimulating calcium efflux is ATP greater than AMP-PCP greater than cAMP greater than AMP greater than adenine approximately NAD approximately NADH. Non-adenine-containing nucleotides such as GTP, CTP, UTP, and ITP and the high energy phosphate compound, acetyl phosphate, were ineffective in stimulating oxidation-induced calcium efflux. The relative effectiveness of various adenine nucleotides in stimulating calcium-induced calcium efflux and oxidation-induced calcium efflux are identical, suggesting that a common mode of action is involved when calcium release is triggered by either method. The stimulatory effect of the adenine nucleotides on oxidation-induced efflux is independent of external magnesium concentration and independent of the magnesium gradient across the SR membrane.

Adenine Nucleotides↗