Biomedical subjects
Publications and source records attributed to L Weeks.
The scanning tunnelling microscopy imaging of [3 x 3] Mn(II) nonanuclear grids on gold substrates is described. Self-assembled behaviour is observed at both high and low coverage, with submolecular resolution of individual molecules displayed at low deposition concentrations. The importance of proper image processing techniques is demonstrated in resolving the layer structure at high coverage.
Clinical studies have indicated that high plasma levels of fibrinogen, or decreased fibrinolytic potential, are conducive to an increased risk of cardiovascular disease. Other investigations have shown that insoluble fibrin promotes atherosclerotic lesion formation by affecting smooth muscle cell proliferation, collagen deposition, and cholesterol accumulation. To directly assess the physiological impact of an imbalanced fibrinolytic system on both early and late stages of this disease, mice deficient for plasminogen activator inhibitor-1 (PAI-1(-/-)) were used in a model of vascular injury/repair, and the resulting phenotype compared to that of wild-type (WT) mice. A copper-induced arterial injury was found to generate a lesion with characteristics similar to many of the clinical features of atherosclerosis. Fibrin deposition in the injured arterial wall at early (7 days) and late (21 days) times after copper cuff placement was prevalent in WT mice, but was greatly diminished in PAI-1(-/-) mice. A multilayered neointima with enhanced collagen deposition was evident at day 21 in WT mice. In contrast, only diffuse fibrin was identified in the adventitial compartments of arteries from PAI-1(-/-) mice, with no evidence of a neointima. Neovascularization was observed in the adventitia and was more extensive in WT arteries, relative to PAI-1(-/-) arteries. Additionally, enhanced PAI-1 expression and fat deposition were seen only in the arterial walls of WT mice. The results of this study emphasize the involvement of the fibrinolytic system in vascular repair processes after injury and indicate that alterations in the fibrinolytic balance in the vessel wall have a profound effect on the development and progression of vascular lesion formation.
We studied the molecular basis of low hepatic lipase (HL) activity in normolipidemic male patients with angiographically documented coronary artery disease (CAD). In 18 subjects with a lowered HL activity (< 225 mU/mL), all nine exons of the HL gene and part of the promoter region (nucleotides -524 to +7) were sequenced. No structural mutations in the coding part of the HL gene were found, but 50% of the subjects showed a C-to-T substitution at nucleotide -480. Screening for the base substitution in 782 patients yielded an allele frequency of 0.213 (297 heterozygotes, 18 homozygotes). In a group of 316 nonsymptomatic control subjects, the allele frequency was 0.189, which is significantly less than in the CAD patients (P = .035). In the CAD patients, the C-to-T substitution was associated with a lowered lipase activity (heterozygotes -15%, homozygotes -20%). The patients were divided into quartiles on the basis of HL activity. Sixty percent (allele frequency 0.32) of the patients in the lowest quartile (HL activity < 306 mU/mL) had the gene variant against 27% (allele frequency 0.14) in the highest quartile (HL activity > 466 mU/mL). In the noncarriers, but not in the carriers, HL activity was related with plasma insulin, being increased at higher insulin concentration. Homozygous carriers had a significantly higher HDL cholesterol level-than noncarriers (1.13 +/- 0.28 mmol/L versus 0.92 +/- 0.22 mmol/L, P < .02). Our results show that a C-to-T substitution at -480 of the HL promoter is associated with a lowered HL activity. The base substitution, or a closely linked gene variation, may contribute to the variation in HL activity and affect plasma lipoprotein metabolism.
In 1989, Hermann Hospital and University of Texas-Houston Health Science Center School of Nursing applied for and received approval to implement a 5-year demonstration project funded by the Health Care Finance Administration using Medicaid pass-through funds to educate nurses at the graduate level. The project aimed to evaluate the impact of advanced practice nurses and researchers on the practice of professional nursing at a 655-bed acute-care hospital in a large metropolitan area. The authors describe the factors that served to galvanize the two institutions to apply for such a grant, discuss the barriers encountered along the course of the project, and list the outcomes achieved by 1994 or project end. Predictions regarding the second 5-year segment (phase 2) are summarized as well. The article includes suggestions to other institutions interested in replicating such a project.
Previous reports documenting the essentially identical spectra of activity of ceftizoxime, cefotaxime, and ceftriaxone prompted our hospital formulary committee to replace the latter two drugs with ceftizoxime on the basis of cost differences. However, we subsequently observed that every one of 60 isolates of Streptococcus pneumoniae tested was less susceptible to ceftizoxime than to either cefotaxime or ceftriaxone. The difference between minimal inhibitory concentrations (MICs) was greatest for strains moderately or fully resistant to penicillin, which at our institution represent approximately 32% of all isolates of S. pneumoniae. Ten isolates with cefotaxime and ceftriaxone MICs of 2.0-6.0 micrograms/mL had ceftizoxime MICs of > or = 256 micrograms/mL. Time-kill kinetic studies assessing bactericidal activity confirmed the diminished activity of ceftizoxime against penicillin-resistant isolates of S. pneumoniae. Ceftizoxime should not be used to treat proven or suspected pneumococcal infection in areas where resistance to penicillin is prevalent.
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The incidence of long-term pain (between 1 and 48 weeks and at 2 year follow-up) unrelated to the surgical site following either regional brachial plexus or general anaesthesia was determined. In 834 patients with regional anaesthesia, the incidence (11.1%) was significantly higher than in the 86 patients with general anaesthesia (3.6%; P = 0.03). The incidence of pain was not significantly different among four common techniques of positioning the needle tip in the axillary sheath (9.9 to 11.1%). Parascalene blocks had a slightly but not significantly higher rate (16.3%). A regional re-block was not associated with a higher incidence when compared to those blocked only once. A more distal local re-block was associated with a higher incidence of pain (23%). 2 years post-operatively, 0.5% of patients had pain related to the regional block. A significant proportion of patients developed some long-lasting post-operative pain following regional brachial plexus anaesthesia, although ultimate morbidity was minimal.
In 26 type 2 diabetic patients with failure to diet and sulphonylureas (fasting blood glucose levels greater than 8.0 mmol/l) the effects of insulin therapy on blood glucose control, islet B-cell function and plasma lipids were studied. Age was 58 +/- 11 (SD) yr, median duration of diabetes 6.5, range 1-24 yr, and body mass index 24.5, range 18.9-36.3 kg/m2. Six patients were obese. Therapy comprised twice daily injections of intermediate-acting insulin with additional fast-acting insulin when necessary. After six months, insulin dose was 39 +/- 10 U in the non-obese patients. Their fasting (14.0 +/- 2.7 mmol/l) and post-prandial blood glucose (17.9 +/- 4.5 mmol/l) and glycosylated haemoglobin (HbA1, 13.0 +/- 2.0%) declined to 7.7 +/- 1.6 mmol/l, 10.6 +/- 2.6 mmol/l and 9.5 +/- 1.0%, respectively (p less than 0.001). Median body weight increased by 3.7 kg (p less than 0.001). The changes in body weight correlated well with the changes in fasting blood glucose (r = -0.75, p less than 0.01) and HbA1 (r = -0.73, p less than 0.01). Fasting plasma insulin increased (p less than 0.01), whereas fasting plasma C-peptide and C-peptide release after glucagon did not change. Free fatty acids, LDL-cholesterol, total and VLDL-triglycerides showed a significant (p less than 0.05) decrease during insulin treatment. In the six obese patients insulin dose after six months was 44 +/- 18 U. Fasting blood glucose fell from 11.3 +/- 2.2 to 8.8 +/- 2.7 mmol/l (p less than 0.01), and HbA1 decreased from 10.7 +/- 1.1% to 9.8 +/- 1.3% (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
In 13 non-obese patients with Type 2 diabetes mellitus who failed to achieve adequate blood glucose control on dietary treatment (fasting blood glucose 13.4 +/- 2.7 (+/- SD) mmol l-1, glycosylated haemoglobin 13.0 +/- 1.7%), the effects of 6 months insulin or sulphonylurea therapy on blood glucose control and lipid metabolism were compared in a randomized crossover study. Three patients, who showed a clear improvement on insulin (median glycosylated haemoglobin fell from 14.7 to 8.6%), withdrew from the study prematurely because of subjective and objective signs of hyperglycaemia after crossover from insulin to sulphonylurea. Daily dose after 6 months was 2000 mg tolbutamide (n = 3), 18 +/- 1 mg glibenclamide (n = 7), or 34 +/- 3 U insulin. On insulin, fasting (8.0 +/- 1.9 mmol l-1) and postprandial blood glucose (10.4 +/- 2.7 mmol l-1), and glycosylated haemoglobin (9.5 +/- 1.1%) were lower than on sulphonylurea (11.0 +/- 3.4 mmol l-1, 14.4 +/- 4.8 mmol l-1 and 11.0 +/- 2.5%, respectively, p less than 0.05 in each case). Median increase in body weight was greater on insulin (4.2 vs 1.1 kg, p less than 0.05). Six patients experienced improved well-being on insulin compared with sulphonylurea. Median plasma non-esterified fatty acids decreased from 825 mumol l-1 to 476 mumol l-1 (sulphonylurea) and 642 mumol l-1 (insulin, both p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
The adversarial relationships existing in 1982 among medical students, nurses, and hospital staff members were recognized at Hermann Hospital, a private, nonprofit teaching hospital in Houston, Texas, to be potentially detrimental to patient care. A joint communications committee--composed of medical students, faculty members, and hospital and nursing administrators--was developed to identify ways to improve relations between medical students and hospital personnel. The results of the committee's efforts have been an orientation program offered to medical students by the hospital prior to their third-year clerkships; elective workshops for second-year students on skills such as venipuncture, ventilatory management, and physiologic monitoring taught by practicing nurses and other health care personnel; and roundtable seminars for all medical students. Three years after its inception, the committee continues to offer and refine the orientation program and skills workshops. In the authors' opinion, the success of the committee can be attributed to the fact that medical students have been instrumental in directing and evaluating the programs.
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At the 2001 MHA Annual Corporate Membership Meeting in June, the Michigan Association of Hospital Auxiliaries (MAHA) saw one president step down and a new one begin a one-year appointment. The following are the thoughts of each woman as they assume their respective positions as counselor and president.
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