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Biomedical subjects

M W Stewart

Publications and source records attributed to M W Stewart.

At least 55 records · Page 3Linked to original sources
PubMed1994

Differential relationships between stress and disease activity for immunologically distinct subgroups of people with rheumatoid arthritis.

Immunologically distinct subgroups of patients with rheumatoid arthritis (RA)--those with the autoantibody rheumatoid factor (seropositive RA) and those without (seronegative RA)--were compared on a variety of clinical and self-report measures in a consecutive series of women with disease of 7 years' or less duration. The groups were comparable on clinical, pain, functional, and psychosocial variables. However, the seronegative RA group reported elevated levels of preonset negative life event stress. Postonset life event stress and disease activity were significantly correlated for the seronegative RA group, but not for the seropositive RA group. Results suggest that stress factors may be more important in the etiology and maintenance of seronegative RA and that the seronegative RA group may possibly derive particular benefit from psychological techniques to enhance stress management skills.

Adult↗
PubMed1994

The contribution of lipids to coronary heart disease in diabetes mellitus.

Cardiovascular disease is two to three times more common in diabetic patients than in the non-diabetic population. Although risk factors that affect the general population such as age, cigarette smoking, hypertension, obesity and hypercholesterolaemia also affect diabetic subjects, the increased prevalence of hypertension and obesity in non-insulin-dependent diabetes mellitus (NIDDM) only partially explains the increased morbidity and mortality from coronary heart disease (CHD). Other factors must therefore be considered in this group of patients. Triglyceride concentrations, particularly post-prandial levels, may be important. Diabetic subjects have increased very-low-density-lipoprotein (VLDL), increased intermediate-density-lipoprotein (IDL) and low high-density-lipoprotein (HDL) concentrations, and differences in lipoprotein composition may partly explain increased atherogenesis. Although LDL levels of diabetic patients are not different from those of control subjects. LDL particles are potentially atherogenic as they are smaller, more dense and prone to oxidative modification. NIDDM subjects also have altered apolipoprotein concentrations, including increased apoB, apoC-III, and decreased apoA-I; in addition, apoE-2 may be over-represented in diabetic populations. Thus, apart from the traditional risk factors, there are several lipoprotein compositional abnormalities that may contribute to the increased prevalence of CHD in diabetes.

Apolipoproteins↗
PubMed1993

Detection of antiphospholipid antibodies by flow cytometry: rapid detection of antibody isotype and phospholipid specificity.

Laboratory diagnosis of antiphospholipid antibodies is important in patients with clinical features of the antiphospholipid syndrome, such as thrombosis and fetal loss. We have developed a novel method for the detection of antiphospholipid antibodies using flow cytometry. Anionic phospholipids cardiolipin, phosphatidylserine and phosphatidylinositol are coated onto polystyrene beads of different sizes, allowing detection and semiquantitation of their respective phospholipid antibody isotypes. The results of the flow cytometric method closely correlate those of the standardised anticardiolipin enzyme-linked immunosorbent assay (ELISA), but the method is quicker and is versatile in its ability to detect IgG, IgM and IgA antibody isotypes at the same time. The method promises to be useful in evaluating the significance of phospholipid specificity and antibody isotypes in patients with the antiphospholipid syndrome.

Antibodies, Antiphospholipid↗
PubMed1993

A self-report articular index: relationship to variations in mood and disease activity measures.

Self-report can provide an inexpensive method for monitoring disease activity or treatment response in RA, but may be affected by confounding variables such as the patient's mood. The relationship of a self-report articular index (AI) to other relevant parameters was assessed from data gathered at approximately monthly intervals from 16 women with RA. Statistical analysis showed that the AI covaried most strongly with other measures of disease activity and functional disability, while mood variables and ESR covaried separately. These results indicated that responses on the self-report AI paralleled disease activity, and were not merely an artifact of variations in the patient's mood.

Adult↗
PubMed1993

Lipoprotein compositional abnormalities and insulin resistance in type II diabetic patients with mild hyperlipidemia.

Lipoprotein composition was determined using ultracentrifugation in 20 non-insulin-dependent (NIDDM) diabetic patients on diet only (D), 20 NIDDM patients on diet and sulfonylurea therapy (T), and 20 nondiabetic control subjects (C), all of whom had total plasma cholesterol concentrations < 6.5 mmol/L and total plasma triglyceride concentrations < 3.0 mmol/L. Although the groups were well matched for age, body mass index, total triglyceride levels, and total cholesterol concentrations, there were significant compositional abnormalities in the low-density lipoprotein (LDL) fractions of diabetic subjects. The LDL total lipid to apolipoprotein B weight ratio (representing the density distributions of LDL particles) was reduced in both diabetic groups: 3.75 +/- 0.3, 3.50 +/- 0.28, and 3.54 +/- 0.22 in C, D, and T groups, respectively (mean +/- SD; P < .05). This was associated with a significant shift in the hydrated density distributions of LDL in the diabetic groups, with the average peak densities being 1.0320 g/mL (in C), 1.0365 g/mL (in D), and 1.0380 g/mL (in T) (P < .05). The LDL particles were also smaller in the NIDDM patients: 21.1 +/- 0.7, 20.4 +/- 0.5, and 20.6 +/- 0.5 nm in C, D, and T groups, respectively (P < .05). When the NIDDM groups were analyzed together, the LDL peak density was found to correlate with both insulin resistance (measured by a modified Harano technique; r = 0.37, P < .015) and total triglyceride concentrations (r = 0.40, P < .01). The results show that diabetic patients have small, dense LDL particles, which may be related to insulin resistance, and that these occur with minimal elevations of total triglyceride concentrations. These potentially atherogenic changes may contribute to the increased coronary heart disease in diabetic patients with mild hyperlipidemia.

Aged↗
PubMed1993

Subretinal hemorrhage after grid laser photocoagulation for idiopathic juxtafoveolar retinal telangiectasis.

A 56-year-old man had decreased vision secondary to bilateral idiopathic juxtafoveolar retinal telangiectasis. One month after grid laser photocoagulation for macular edema in the right eye, a subretinal hemorrhage developed. Over the next 2 months, the hemorrhage spontaneously resorbed and vision improved to 20/50. At 2-year follow up, without further treatment, vision was still 20/50.

Fluorescein Angiography↗
PubMed1992

Management of dislocated lens fragments during phacoemulsification.

BACKGROUND: Dislocation of nuclear lens fragments during phacoemulsification can lead to a high incidence of glaucoma, uveitis, and poor visual acuity. The correct approach to these patients is uncertain. The authors report on eight patients who underwent pars plana vitrectomy with removal of lens fragments. METHODS: Charts of eight consecutive patients who developed dislocation of nuclear lens fragments into the vitreous cavity during phacoemulsification were retrospectively reviewed. All patients underwent a standard three-port pars plana vitrectomy with removal of the dislocated nuclear fragments by pars plana fragmentation. After the vitrectomy, the retina was inspected with indirect ophthalmoscopy. Tears were treated with cryopexy. A fluid-air exchange and scleral buckle were performed when indicated. RESULTS: Retinal tears were located at the vitreous base in four of eight patients. After vitrectomy, visual acuity improved in all patients, with 7 of 8 patients achieving visual acuity of 20/40 or better. The type of pseudophakia did not influence the final visual acuity. There were no cases of glaucoma, uveitis, or macular edema with up to 22 months of follow-up. CONCLUSIONS: These results suggest that large nuclear fragments dislocated into the posterior segment during phacoemulsification can be removed safely with pars plana vitrectomy and lensectomy with an excellent visual prognosis. Attempts to remove lens fragments during the phacoemulsification through an anterior wound should be avoided because of excessive vitreous traction, leading to retinal break formation.

Aged↗
PubMed1992

An experimental model of ectropion uveae and iris neovascularization in the cat.

Neovascularization of the iris (NVI) is one of the most frequently studied intraocular vascular proliferations in animal models. Ectropion uveae has not been a consistent finding in these studies. In this study, a surgical model of ectropion uveae and iris neovascularization was developed that involved lensectomy, vitrectomy, bipolar cautery and transection of all three principal branch veins in the cat eye. Twelve of 14 eyes that received this procedure developed postoperative retinal detachments with a clinical picture of hemorrhagic retinopathy. These eyes progressed to a clinical picture of NVI within 1-7 wk. Eight eyes developed ectropion uveae for as much as 300 degrees. At the light microscopic level, a fibrovascular membrane was apparent on the anterior iris stroma in 9 of 14 eyes and further involved the angle in six eyes.

Animals↗
PubMed1991

Coping strategies and affect in rheumatoid and psoriatic arthritis. Relationship to pain and disability.

Affective state and utilization of coping strategies are factors that may be related to pain and disability in chronic disease, but may also be interrelated. The relationship of coping strategies and affect to both concurrent and 18-month follow-up pain and disability was studied in 60 women with rheumatoid or psoriatic arthritis of < 8 years' duration. The type of coping strategy used was not associated with concurrent mood level. After accounting for physical variables, mood and strategy use were significantly, and largely independently, related to concurrent pain and disability measures. Future disability was not predicted by either mood or coping strategy use. These results show that mood and use of coping strategies are significantly related to concurrent function but, perhaps due to the variable nature of the disease process, are not predictive of future function. The clinical implications of this study are that interventions to promote better adjustment for people with rheumatoid or psoriatic arthritis should target both mood and coping strategies, as both may contribute independently to adjustment.

Adaptation, Psychological↗
PubMed1991

Modification of sleep respiratory patterns by auditory stimulation: indications of a technique for preventing sudden infant death syndrome?

Sudden infant death syndrome (SIDS) has been associated with premorbid respiratory irregularities that may contribute to the subsequent occurrence of SIDS (e.g. by chronic hypoxia). Conventional apnea alarms will detect periods of extended apnea but not other chronic respiratory irregularities that could contribute to SIDS. The effect of a brief, quiet, repetitive auditory stimulus on the sleep respiratory behavior of infant dogs and pigs was assessed. Stimulus presentation was associated with an increase in the sleep respiration rate irrespective of the stimulus presentation rate being faster or slower than the baseline respiratory rate, and irrespective of the pattern of presentation being regular or random. These results suggest that apnea monitoring systems may be improved by an additional function in which less extreme respiratory irregularities initiate the time-limited presentation of a quiet, repetitive, auditory stimulus, aimed at normalizing the respiratory pattern. This function could enhance the preventative role of the alarm systems by reducing the development of pathology that may promote some instances of SIDS.

Acoustic Stimulation↗
PubMed1991

Sudden blindness associated with central nervous symptoms in a hemodialysis patient.

Purtscher's-like retinopathy as a cause of sudden blindness in hemodialysis patients is not widely known. This is believed to occur secondary to leukoembolization to retinal arterioles following complement activation. We describe a patient who developed sudden but reversible loss of vision on hemodialysis associated with varying reversible neurological signs and symptoms which we felt may have been a manifestation of leukoembolic aggregates lodging in the arterioles of the retina and central nervous system circulations.

Adult↗