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Biomedical subjects

L Morgan

Publications and source records attributed to L Morgan.

At least 37 records · Page 2Linked to original sources
PubMed2001

Occurrence of pulmonary thromboembolism immediately after arthroplasty.

INTRODUCTION: Respiratory complications are common after arthroplasty, with pulmonary thromboembolic disease (PTE) and fat emboli being the most serious. A scintigraphic study was designed to assess the occurrence of both diseases. A prospective tomographic study of perfusion was performed within 24 h of arthroplasty. Details of the detection of fat embolism will be presented elsewhere. METHODS: Patients with previous PTE were excluded. Tomographic lung studies were acquired after 99mTc-macroaggregated albumin injection. Pre- and post-operative arterial blood gases (ABGs) and relevant chest radiography/computed tomography scans were obtained. ABGs were analysed as the difference in alveolar-arterial oxygen gradients, pre- and post-operatively (DA-a). RESULTS: Forty patients were studied (16F, 24M) with a mean age of 71 years (range 36-88 years). Of these, 16 were hip and 24 knee arthroplasties. PTE was detected in 25 of 38 (66%) patients evaluated. The value of DA-a was significantly different between patients with PTE and without PTE (P>0.05). Administration of prophylactic pre-operative low molecular weight heparin makes no difference to the early onset of PTE. CONCLUSION: There is a high incidence of PTE immediately after arthroplasty.

Arthroplasty, Replacement, Hip↗
PubMed2001

Postprandial triacylglycerol responses in simulated night and day shift: gender differences.

A number of reports suggest that shift workers have an increased risk of coronary heart disease (CHD). One contributing factor may be the consumption of meals at night with consequent altered postprandial responses. This study investigated circulating triacylglycerol (TAG), a possible risk factor for CHD, after meals during a simulated day and night shift. Twenty-five healthy participants (10 women and 15 men) were studied. They were given a pre-meal at 0800 h and a test meal at 1330 h on a simulated day shift and then an identical pre-meal at 2000 h and test meal at 0130 h, respectively, on a simulated night shift with maintained wakefulness. Blood was sampled for 9 h after the test meal for analysis of basal and postprandial plasma TAG levels. ANOVA for repeated measures indicated higher TAG in men compared with women (p < 0.0001) and higher responses at night in both genders (p = 0.027). Incremental area under the curve (IAUC) analysis indicated that men had significantly increased postprandial TAG levels at night compared with the day: (IAUC 0-540 min, mean +/- SEM) 253.29 +/- 28.73 versus 148.33 +/- 17.28 mmol/L x min, respectively, p = 0.025. In women, night and day responses (61.16 +/- 8.93 versus 34.09 +/- 7.87 mmol/L x min, respectively, p = 0.457) were not significantly different. Circulating TAG remained elevated for longer at night in the men compared with the women (p = 0.009). This study demonstrates the existence of gender and time-of-day differences in TAG responses to a meal. These raised TAG levels at night, for a prolonged time in men, may be relevant to the increased risk of CHD in shift workers.

Adult↗
PubMed2000

Vascular endothelial growth factor stimulates dephosphorylation of the catenins p120 and p100 in endothelial cells.

Vascular endothelial growth factor (VEGF) is an endothelium-specific mitogen that induces angiogenesis and increases vascular permeability. These processes involve regulation of cell-cell adhesion, but molecular mechanisms have yet to be fully established. p120, also termed p120(ctn), and its variant p100 are catenins which associate with cadherins and localize to adherens junctions. VEGF was reported to stimulate tyrosine phosphorylation of catenins in endothelial cells. In contrast, we have found that VEGF potently stimulated a rapid and dose-dependent decrease in serine/threonine phosphorylation of p120 and p100. VEGF acted via VEGF receptor 2 to achieve this effect which was independent of activation of the extracellular-signal-regulated kinase pathway. Histamine and activators of protein kinase C had a very similar effect to that of VEGF on phosphorylation of p120 and p100, suggesting that these diverse stimuli may converge on a common signalling element regulating p120/p100 serine/threonine phosphorylation. These data raise the possibility that the dephosphorylation of p120 and p100 triggered by VEGF may contribute to mechanisms regulating permeability and/or motility through modulation of cadherin adhesiveness.

Cadherins↗
PubMed2000

Effect of a comprehensive infection control program on the incidence of infections in long-term care facilities.

BACKGROUND: Control of infection within the long-term care facility is a daunting problem. Elderly patients are at high risk for contracting infection because of reduced innate immunity, malnutrition, and the presence of chronic medical conditions. This small study tested the effect of developing and implementing a comprehensive preventive infection control program in the long-term care setting and examined the resultant incidence of infections. METHODS: Eight private, freestanding, long-term care facilities in urban and suburban settings were selected for the study. The 4 test sites had a total of 443 beds; there were 447 beds in 4 matched control sites. Data on infection rates were accrued in both preintervention and intervention years. The control homes maintained their existing infection control policies and procedures. The test homes were provided with an infection control educational program and replaced all currently used germicidal products with single-branded products for a 12-month period. A criteria-based standardized infection control surveillance system was used to monitor and report infections in all facilities. RESULTS: In the preintervention year, the test sites experienced 743 infections (incidence density rate, 6.33) and the control homes experienced 614 infections (incidence density rate, 3.39). In the intervention year, the test homes reported 621 infections, a decrease of 122 infections (incidence density rate, 4.15); in the control homes, the number of infections increased slightly, to 626 (incidence density rate, 3.15). The greatest reduction in infections in the test homes was in upper respiratory infections (P =.06). CONCLUSIONS: This study provides additional evidence that a comprehensive infection control program that includes handwashing and environmental cleaning and disinfecting may help reduce infections among the elderly residing in long-term care settings.

Age Distribution↗
PubMed2000

Polymorphism in oestrogen response element associated with variation in plasma angiotensinogen concentrations in healthy pregnant women.

OBJECTIVE: To investigate the hypothesis that the genotype at nucleotide A(-20)C in the 5' flanking region of the angiotensinogen gene, which lies within a sequence with high homology to an oestrogen response element, affects plasma angiotensinogen levels in pregnancy. DESIGN: Prospective observational study METHODS: Seventy-two healthy pregnant women were recruited in the second half of pregnancy from hospital and primary care antenatal clinics in Nottingham, UK. Plasma angiotensinogen concentrations were measured by radioimmunoassay of angiotensin I generated from endogenous angiotensinogen in the presence of excess human renin. DNA was extracted from peripheral venous blood, and angiotensinogen genotype determined at A(-20)C, G(-6)A and Met235Thr. Associations between genotype and plasma angiotensinogen concentration were assessed by analysis of variance. RESULTS: Women homozygous for the -20C allele had the lowest mean plasma angiotensinogen concentration of 1.7 +/- 0.3micromol/l. Women homozygous for -20A had significantly higher plasma angiotensinogen concentrations (2.6 +/- 0.1 micromol/l), and intermediate levels (2.0 +/- 0.1 micromol/l) were observed in women heterozygous for A(-20)C (P = 0.002, ANOVA). The polymorphisms at nucleotide -6 and codon 235 were in almost complete linkage disequilibrium, and nucleotide -20C was found only in a subset of -6A/235Thr alleles. Conclusion The low plasma angiotensinogen levels associated with the -20C/-6A/235Thr haplotype in pregnant women contrast with the high concentrations associated with the 235Thr allele in the non-pregnant state. A possible explanation lies in the presence of a motif with high homology to an oestrogen response element between the TATA box and transcription initiation site. Previous in vitro studies of reporter gene constructs have demonstrated thatthe A(-20)C polymorphism affects oestrogen responsiveness. The results of this study support the hypothesis that the oestrogen response element of the angiotensinogen gene is of functional importance in pregnancy, and that oestrogen responsiveness in pregnancy is influenced by the genotype at nucleotide - 20.

Alleles↗
PubMed2000

Hyperproinsulinaemia in elderly subjects: evidence for age-related pancreatic beta-cell dysfunction.

We investigated whether pancreatic beta-cell dysfunction has a role in the pathogenesis of glucose intolerance in the elderly by comparing plasma glucose, immunoreactive insulin, C-peptide and proinsulin concentrations during a 100-g oral glucose load in six healthy older male volunteers [aged 69 (65.9-74.9) years; median (95% confidence limits)] and seven young male controls [aged 24.0 (21.9-26.3) years]. Fasting and integrated concentrations of glucose and C-peptide were similar in the elderly and young. Although fasting, insulin and proinsulin levels were similar, integrated insulin (P=0.05) and proinsulin (P<0.05) concentrations were higher in the elderly than in controls. Insulin resistance, measured as homeostasis model assessment, was greater (P<0.05) in the elderly than in controls. Elderly men had greater molar ratios of integrated insulin:C-peptide (P<0.05) and proinsulin:C-peptide (P<0.01) but their respective fasting molar ratios were similar when compared with controls. Pancreatic beta-cell secretion in older subjects, as assessed by C-peptide concentrations, was inappropriately low in the presence of insulin resistance. Their post-prandial 'hyperinsulinaemia' is probably due to a combination of hyperproinsulinaemia and reduced metabolic clearance of insulin. Older subjects had disproportionately high proinsulin to C-peptide levels, suggesting pancreatic beta-cell dysfunction. These results are consistent with the notion that decreased insulin sensitivity and pancreatic beta-cell dysfunction may predispose the elderly to glucose intolerance.

Adult↗
PubMed2000

Achieving a credible health and safety approach to increasing seat belt use among African Americans.

African American youth are 60 percent less likely than children from other racial or ethnic backgrounds to be buckled up. Seat belt use among African American males has largely remained stagnant while that for other groups has increased. Overall, African Americans buckle up less often than other racial or ethnic populations. Seat belt use is a preventive health care action within public health. Clearly, a credible health and safety message is not being communicated effectively to African American communities. This paper proposes a number of possible solutions, including: recognition of the role that health care providers play in shaping patient or consumer attitudes and subsequent behavior in terms of prevention of disease and injury, educating physicians and health care providers to routinely recommend seat belt use especially for children, culturally appropriate educational safety programs, an improved relationship between law enforcement and communities, and zero tolerance for nonuse of seat belts.

Adolescent↗
PubMed2000

A decade review: methods to improve adherence to the treatment regimen among hemodialysis patients.

Hemodialysis patients are asked to adhere to a very difficult treatment regimen consisting of fluid and diet restrictions, many daily medications, and, usually, 3- or 4-hour hemodialysis sessions three times each week. Many hemodialysis patients fail to adhere to their prescribed treatment. Although this regimen is difficult, it is necessary for patients to adhere to the prescribed regimen for optimal health and well-being. It is important for nephrology nurses to know what interventions help patients overcome the barriers that keep them from adhering to the prescribed treatment. The purpose of this paper is to review the literature to examine the research that has been published on methods to improve adherence to the treatment regimen among hemodialysis patients. Behavioral approaches, education, and primary nursing are interventions that have been researched. More research has been reported on the demographics of noncompliant hemodialysis patients than on effective methods that help patients improve adherence to the treatment regimen. Demographic characteristics do not consistently predict compliance for individual patients. Each patient is unique. Research supports the idea that the nephrology nurse should spend time with the patient on a regular basis in order to understand the factors that hinder the individual patient from adhering to the treatment regimen. The nurse who knows the patient well is empowered to develop individualized interventions aimed at reducing barriers that interfere with the patient's ability to adhere the prescribed treatment regimen.

Humans↗
PubMed1999

Evaluation of polymorphisms in the presenilin-1 gene and the butyrylcholinesterase gene as risk factors in sporadic Alzheimer's disease.

The E4 allele of the apolipoprotein E gene (APOE) is a major risk factor for late-onset Alzheimer's disease (LOAD) but is neither necessary nor sufficient to cause the disease. In this study, we investigated polymorphisms in the presenilin-1 (PS-1), and butyrylcholinesterase (BChE) genes, which have been implicated as risk factors for LOAD. Our data-set comprised 177 AD and 118 control patients, all of whom had been histopathologically confirmed following autopsy. We have tested homozygosity for the PS-1 allele 1 and possession of the BChE-K variant in association with APOE epsilon4 as risk factors in LOAD. Our findings support an association between the PS-1 polymorphism and LOAD, finding homozygosity for allele 1 associated with an approximately two-fold increased risk. Our data also show that in subjects greater than 75 years of age possession of both BChE-K and APOE-epsilon4 alleles is associated with an increased risk of LOAD, whilst the risk associated with APOE-epsilon4 allele alone is not significant.

Aged↗
PubMed1999

Inhibition of carbohydrate-mediated glucagon-like peptide-1 (7-36)amide secretion by circulating non-esterified fatty acids.

Two studies were performed to assess the entero-insular axis in simple obesity and the possible effect of variations in the level of circulating non-esterified fatty acids (NEFA) on one of the components of the entero-insular axis, glucagon-like peptide-1 [(7-36) amide]. In the first study, we compared the entero-pancreatic hormone response to oral carbohydrate in obese and lean women. Obese subjects demonstrated hyperinsulinaemia and impaired glucose tolerance but this was not associated with an increased secretion of either glucose-dependent insulinotropic polypeptide or glucagon-like peptide-1 (GLP-1). These findings therefore provide no support for the hypothesis that overactivity of the entero-insular axis contributes to the hyperinsulinaemia seen in obesity. Indeed, the plasma GLP-1 response to carbohydrate was markedly attenuated in obese subjects, confirming previous observations. In the second study, in which carbohydrate-stimulated GLP-1 responses were again evaluated in obese and lean women, circulating NEFA levels were modulated using either heparin (to increase serum NEFA) or acipimox (to reduce serum NEFA). Treatment with acipimox resulted in complete suppression of NEFA levels and in a markedly higher GLP-1 response than the response to carbohydrate alone or to carbohydrate plus heparin. We suggest that higher fasting and postprandial NEFA levels in obesity may tonically inhibit nutrient-mediated GLP-1 secretion, and that this results in attenuation of the GLP-1 response to carbohydrate. However, although serum NEFA levels post-acipimox were similarly suppressed in both lean and obese subjects, the GLP-1 response was again significantly lower in obese subjects, suggesting the possibility of an intrinsic defect of GLP-1 secretion in obesity. The reduction of GLP-1 levels in obesity may be important both in relation to its insulinotropic effect and to its postulated role as a satiety factor.

Adult↗