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Biomedical subjects

M Elliott

Publications and source records attributed to M Elliott.

At least 73 records · Page 4Linked to original sources
PubMed1998

Repeatability and comparability of automated keratometry: the Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer.

This study assessed the repeatability of the Nikon NRK-8000, the Nidek KM-800 and the Bausch and Lomb keratometer. In addition, the comparability of the Nikon NRK-8000 and the Nidek KM-800 are evaluated relative to the Bausch and Lomb keratometer. Measurements were taken with all three techniques on two separate occasions with a test-retest separation of at least 24 hr. The right eyes of 30 normal subjects were used. Repeatability and comparability statistics and plots were generated using matrix representations of dioptric power. The Nidek KM-800 coefficient of repeatability values were found to be 0.345, 0.187, and 0.321 in the vertical, torsional, and horizontal meridians while the Nikon NRK-8000 values were 0.346, 0.232, and 0.276 respectively.

Adult↗
PubMed1997

A networking approach to clinical supervision.

Clinical supervision offers support in clinical and professional development. This article discusses a number of approaches to supervision and describes the use of a networking model when a nursing development unit was created.

Education, Nursing, Continuing↗
PubMed1997

Pilot study of the combination of interferon alfa and ribavirin as therapy of recurrent hepatitis C after liver transplantation.

Recurrent hepatitis C virus (HCV) in liver transplant patients is a major cause of graft loss, liver failure, and need for retransplantation. The results available to date with the use of interferon alfa (IFN-alpha) in the treatment of recurrent HCV in liver transplant patients have been disappointing. The aim of this study was to evaluate the efficacy and clinical utility of post-transplant combination therapy with IFNalpha2b (3 million units 3 times weekly) and oral ribavirin (1,200 mg/d) for a duration of 6 months, followed by maintenance with ribavirin alone for an additional 6 months. Twenty-one liver transplant recipients with recurrent hepatitis C infection (HCV-RNA-positive; active hepatitis without rejection on biopsy) were enrolled in this study. Pretreatment serum alanine transaminase (ALT) levels were at least two times the upper limit of normal. Before treatment, all patients were HCV-RNA-positive and mean HCV-RNA titers were 125 million genome-equivalents/mL. Mean pretreatment histological score was 6.3 +/- 2. After 6 months of combination therapy, all 21 patients had normal ALTs. Ten patients (48%) cleared HCV-RNA from their serum, as assessed by polymerase chain reaction (PCR), and HCV-RNA levels decreased significantly in the others (P = .0001). Improvement in histological score was seen in all patients after combination therapy (P = .0013). During maintenance ribavirin monotherapy, ALT remained normal in all but 1 of the 18 patients who tolerated therapy. HCV-RNA reappeared in 5 patients, but HCV-RNA levels did not return to pretreatment levels (P = .0004). Comparison of pretreatment and postribavirin monotherapy liver biopsies revealed improvement in all but 1 of the 18 patients who tolerated ribavirin (P = .0002). Side effects were restricted to anemia, which necessitated cessation of ribavirin therapy in 3 patients. No patient experienced graft rejection during the study period. These results are significantly better than those reported with IFN-alpha monotherapy. Most importantly, there was a complete absence of graft rejection. These results suggest that the combination of IFN-alpha and ribavirin is effective in reducing HCV-RNA levels and ameliorating hepatocellular injury in recurrent HCV after liver transplantation, and that maintenance therapy with ribavirin monotherapy can maintain the biochemical and histological response.

Adult↗
PubMed1997

Context dependency of conditioned aversions to water and sweet tastes.

Three experiments exposed rats (Rattus norvegicus) to a discriminative conditioning procedure whereby a specific fluid was followed by lithium in one environment but not in another. This produced context-specific aversion to water, as detected by 2-bottle tests in Experiment 1, and a context-dependent saccharin aversion, which was unaffected by context extinction, in Experiment 2. Experiment 3 found that sucrose preexposure increased contextual control over the aversion established by sucrose-lithium pairings but had no effect on the target context. By contrast, target context exposure during conditioning reduced aversion to this context but did not affect contextual control of the sucrose aversion. In conclusion, depending on the conditioning procedures, contextual control of a taste aversion can be independent of the context's Pavlovian properties.

Animals↗
PubMed1997

Repeatability and accuracy of automated refraction: a comparison of the Nikon NRK-8000, the Nidek AR-1000, and subjective refraction.

This study assessed the repeatability of the Nikon NRK-8000, the Nidek AR-1000, and subjective refraction. In addition, the accuracy of the Nikon and the Nidek were evaluated in comparison to subjective refraction. Measurements were taken with all 3 techniques on 2 separate occasions with a test-retest separation of at least 24 h. The right eyes of 30 normal subjects were used. Repeatability and accuracy statistics and plots were generated using matrix representations of dioptric power. Subjective refraction was the most repeatable method, with the coefficient of repeatability (COR) found to be 0.611, 0.224, and 0.490 in the vertical, torsional, and horizontal meridians. The autorefractors' COR was found to range from 0.712 to 0.826 for the vertical and horizontal meridians, whereas the torsional meridian ranged from 0.224 to 0.319.

Adult↗
PubMed1997

TNF blockade in rheumatoid arthritis: implications for therapy and pathogenesis.

The role of the immune response in rheumatoid arthritis (RA) is a subject of debate, although it is widely believed to be a T-cell-driven disease. Progress is being hindered by lack of convincing evidence of a defined specific antigen initiating or perpetuating the response. Clinical trials using monoclonal antibodies directed against T-cell surface molecules such as CD4. CD5, and CD7 have thus far not provided evidence of efficacy. The negative data may reflect inadequate dosing or could suggest that indiscriminate depletion of T cells is insufficient by itself as a therapeutic strategy. Blocking proinflammatory cytokines (e.g. TNF alpha, IL-1) or augmenting anti-inflammatory cytokines (e.g. IL-10) offers an alternative approach to therapy. Clinical trials using monoclonal anti-TNF alpha have been particularly successful in controlling inflammation and markedly reducing acute phase proteins and cellular ingress. However, because disease invariably relapses, repeated therapy is necessary. Preliminary experience suggests that this is possible. Anti-TNF therapy for RA has defined a molecular target and new approach for treating immuno-inflammatory disorders.

Animals↗
PubMed1997

Regulation of heme biosynthesis in Salmonella typhimurium: activity of glutamyl-tRNA reductase (HemA) is greatly elevated during heme limitation by a mechanism which increases abundance of the protein.

In Salmonella typhimurium and Escherichia coli, the hemA gene encodes the enzyme glutamyl-tRNA reductase, which catalyzes the first committed step in heme biosynthesis. We report that when heme limitation is imposed on cultures of S. typhimurium, glutamyl-tRNA reductase (HemA) enzyme activity is increased 10- to 25-fold. Heme limitation was achieved by a complete starvation for heme in hemB, hemE, and hemH mutants or during exponential growth of a hemL mutant in the absence of heme supplementation. Equivalent results were obtained by both methods. To determine the basis for this induction, we developed a panel of monoclonal antibodies reactive with HemA, which can detect the small amount of protein present in a wild-type strain. Western blot (immunoblot) analysis with these antibodies reveals that the increase in HemA enzyme activity during heme limitation is mediated by an increase in the abundance of the HemA protein. Increased HemA protein levels were also observed in heme-limited cells of a hemL mutant in two different E. coli backgrounds, suggesting that the observed regulation is conserved between E. coli and S. typhimurium. In S. typhimurium, the increase in HemA enzyme and protein levels was accompanied by a minimal (less than twofold) increase in the expression of hemA-lac operon fusions; thus HemA regulation is mediated either at a posttranscriptional step or through modulation of protein stability.

Acclimatization↗
PubMed1997

Investigation of the association between the presence of cytoplasmic residues on the human sperm midpiece and defective sperm function.

Defective sperm function has been identified as one of the most common causes of human infertility. The aim of this investigation was to identify whether the presence of retained cytoplasm on the human sperm midpiece is associated with defective sperm function. Statistical analysis of data demonstrated a strong negative correlation between the presence of residual cytoplasm on the midpiece of spermatozoa in the inseminate and fertilization rate during IVF. Significant negative correlations were also identified between the percentage of spermatozoa in the ejaculate bearing cytoplasmic residues and (i) spermatozoa having membrane integrity and (ii) sperm concentration. A highly significant positive correlation was also revealed between the percentage of spermatozoa in the ejaculate with membrane integrity and the percentage of motile spermatozoa. These correlations suggest that retained cytoplasm is a cause of subfertility. Measurements of the percentage of spermatozoa bearing residual cytoplasm in the IVF inseminate could provide the basis for a simple predictive test before IVF.

Cytoplasm↗
PubMed1996

Understanding the conflicts of patient empowerment.

In line with the emphasis placed by nursing development units on critical scrutiny and practice evaluation, the authors review the patient empowerment nursing literature to identify its practical implications for their clinical area and staff. This article presents some early conclusions arising out of this process and highlights the conflicts which nurses face in ensuring that patients are empowered while maintaining their rights and privacy.

Conflict, Psychological↗
PubMed1996

Effects of inhibition of complement activation using recombinant soluble complement receptor 1 on neutrophil CD11b/CD18 and L-selectin expression and release of interleukin-8 and elastase in simulated cardiopulmonary bypass.

The inflammatory response to cardiopulmonary bypass includes activation of complement and induction of several neutrophil activation pathways. A recombinant soluble form of complement receptor 1 was used as a specific inhibitor of complement activation in simulated cardiopulmonary bypass circuits. Substantial complement activation was observed in these circuits with progressive accumulation of both plasma C3a and terminal complement complex. Soluble complement receptor 1 resulted in a significant reduction in C3a levels (p < 0.01) but did not inhibit terminal complement complex generation. A marked rise in neutrophil CD11b/CD18 expression, simultaneous loss of L-selectin expression, and a progressive accumulation of plasma elastase-alpha 1-antitrypsin occurred and were not affected by soluble complement receptor. However, generation of interleukin-8 in the circuits was inhibited (p < 0.05) by pretreatment with soluble complement receptor. These data suggest that changes in neutrophil activation seen during cardiopulmonary bypass may not be induced directly by anaphylatoxin generation.

CD11 Antigens↗
PubMed1996

Intracardiac repair of lesions associated with atrioventricular discordance.

OBJECTIVE: Discordant atrioventricular (AV) connection is a rare congenital cardiac anomaly. Associated cardiac defects modify the physiology, clinical presentation, and surgical management of these patients. We have reviewed our overall experience with 90 patients operated for lesions associated with AV discordance between 1975-1990. METHODS: 90 patients, consecutively operated between 1975-1990, were reviewed. Patients' charts, angiograms and echocardiograms were studied. Follow-up was obtained from our records or was requested from referring cardiologists/paediatricians. It was completed in December 1992. For the analysis of risk factors of early death we used P values by chi-squared and Fisher's exact test. For the analysis of the triangulated events, we used the Kaplan-Meier method. Variables associated with P value over 0.20 were eliminated. RESULTS: 90 patients aged 6 months-30 years (mean 9.1 year) underwent repair of cardiac anomalies associated with AV discordance. Three patients had total cavopulmonary connection; the remainder received biventricular repair. Most important associated malformations were ventricular septal defect (77), subpulmonary obstruction (68) and tricuspid valve anomaly (21). 59 patients received extracardiac valved conduit, 10 had tricuspid valve replacement. Thirteen patients died in hospital (14%). One year and 10 year actuarial survival rate was 84% and 70% respectively. The most significant factors for early death were: anatomically abnormal tricuspid valve (P < 0.0001), tricuspid valve regurgitation (P < 0.002), date of operation (P < 0.012), preoperative or perioperative complete heart block (P < 0.015), and tricuspid valve surgery (P < 0.05). Complete heart block developed in 17 (20%) out of 85 patients who did not have it preoperatively. During the follow-up, 22 intracardiac reoperations were necessary (4 died). 63 patients of 73 survivors (86%) remain in NYHA Class 1, 6 in Class 2 and 4 in Class 3. CONCLUSIONS: The operative mortality was 14%. Twenty per cent of patients developed complete heart block. These results improved in the later part of the series (1985-1990); mortality decreased to 5% and incidence of heart block to 14%. Cardiac anomalies associated with AV discordance still present a surgical challenge. The data reported in our study should serve as a useful baseline for evaluation of newer surgical techniques, such as the "double switch" operation.

Adolescent↗
PubMed1996

Closure of muscular ventricular septal defects through a left ventriculotomy.

OBJECTIVE: To evaluate the results of closure of muscular ventricular septal defects through a left thoracotomy. METHODS: Records of 23 children operated consecutively between 1972 and 1990 were studied. Age of patients was 2.8 +/- 3 years (2 months-10 years), weight 8.9 +/- 5.7 kg (2.6-22 kg). Ten patients (43%) had undergone one and 4 patients (17%) two previous cardiac operations. Late follow-up was obtained from direct examination of patients or from reports of their referring physicians. Bypass time was 89 +/- 28 min (66-167 min). The aorta was cross-clamped for 44 +/- 15 min (21-66 min). Until 1977 operations were performed with moderate hypothermia and intermittent aortic cross-clamping. After 1978 deep hypothermia (20-25 degrees C) and cold crystalloid cardioplegia was used. Ventricular septal defects not accessible from other approaches were closed through a small fish-mouth incision in the apex of the left ventricle. Patients' data were sampled and stored in a computerised database. Risk factors were evaluated by stepwise logistic regression. RESULTS: Four patients died in the hospital (17%); two died later. Two required reoperation for residual/recurrent defects. All patients, except two from abroad, were available for follow-up, which ranged from 36 months to 18 years (mean 11.3 years). All were in NYHA class I. Only two risk factors were identified: the number of ventricular septal defects (P < 0.05) and associated atrial septal defect (P < 0.02). Early echocardiographic evaluation showed good LV size and function in all except one patient, who had a perioperative septal infarction. Late echocardiography performed in six patients demonstrated normal LV shortening without evidence of regional wall abnormality. CONCLUSIONS: Left ventriculotomy is a useful approach for closure of low muscular ventricular septal defects in selected patients.

Cardiac Catheterization↗
PubMed1996

T-cell mediated rejection of gene-modified HIV-specific cytotoxic T lymphocytes in HIV-infected patients.

The introduction and expression of genes in somatic cells is an innovative therapy for correcting genetic deficiency diseases and augmenting immune function. A potential obstacle to gene therapy is the elimination of such gene-modified cells by an immune response to novel protein products of the introduced genes. We are conducting an immunotherapy trial in which individuals seropositive for human immunodeficiency virus (HIV) receive CD8+ HIV-specific cytotoxic T cells modified by retroviral transduction to express a gene permitting positive and negative selection. However, five of six subjects developed cytotoxic T-lymphocyte responses specific for the novel protein and eliminated the transduced cytotoxic T cells. The rejection of genetically modified cells by these immunocompromised hosts suggests that strategies to render gene-modified cells less susceptible to host immune surveillance will be required for successful gene therapy of immunocompetent hosts.

Antigen Presentation↗
PubMed1996

Midazolam following open heart surgery in children: haemodynamic effects of a loading dose.

Our objective was to establish the safety and effectiveness of a loading dose of midazolam for postoperative sedation of children recovering from open heart surgery; a prospective randomized placebo-controlled double-blind study was done with subjects randomized to three groups according to loading dose. I = 0.08 mg.kg-1; II = 0.04 mg.kg-1; and III = 0.00 mg.kg-1 (placebo). An open label continuous midazolam infusion protocol followed. Haemodynamic parameters were monitored. The study was discontinued following an adverse event involving the 23rd subject. When data for all 23 subjects were combined, there was a mean decrease of 10% in blood pressure (BP) 30 min after the loading dose (P < 0.001). Heart rate change was less significant. Clinicians identified four hypotensive episodes as temporally associated with the midazolam load, two each in Groups I (0.08 mg.kg-1) and III (placebo). One subject in Group I (the 23rd) became hypotensive within five min of receiving the loading dose, had a difficult clinical course and died four weeks postoperatively. We cannot conclude that the loading dose of midazolam had any systematic haemodynamic effect in our study population. Although the clinical course of the 23rd subject suggests a subset of more susceptible children (those who receive opioid analgesia with midazolam, are volume-restricted, and/or undergo more complex forms of surgical correction), many critical care patients are inherently physiologically unstable, and concluding clinically that blood pressure fluctuation is drug related may be erroneous.

Blood Pressure↗