Vesicle-associated brain myosin-V can be activated to catalyze actin-based transport

Myosin-V has been linked to actin-based organelle transport by a variety of genetic, biochemical and localization studies. However, it has yet to be determined whether myosin-V functions as an organelle motor. To further investigate this possibility, we conducted a biochemical and functional analysis of organelle-associated brain myosin-V. Using the initial fractionation steps of an established protocol for the purification of brain myosin-V, we isolated a population of brain microsomes that is approx. fivefold enriched for myosin-V, and is similarly enriched for synaptic vesicle proteins. As demonstrated by immunoelectron microscopy, myosin-V associates with 30–40% of the vesicles in this population. Although a majority of myosin-V-associated vesicles also label with the synaptic vesicle marker protein, SV2, less than half of the total SV2-positive vesicles label with myosin-V. The average size of myosin-V/SV2 double-labeled vesicles (90+/−45 nm) is larger than vesicles that label only with SV2 antibodies (60+/−30 nm). To determine if these vesicles are capable of actin-based transport, we used an in vitro actin filament motility assay in which vesicles were adsorbed to motility assay substrates. As isolated, the myosin-V-associated vesicle fraction was nonmotile. However, vesicles pre-treated with ice-cold 0.1% Triton X-100 supported actin filament motility at rates comparable to those on purified myosin-V. This dilute detergent treatment did not disrupt vesicle integrity. Furthermore, while this treatment removed over 80% of the total vesicle proteins, myosin-V remained tightly vesicle-associated. Finally, function-blocking antibodies against the myosin-V motor domain completely inhibited motility on these substrates. These studies provide direct evidence that vesicle-associated myosin-V is capable of actin transport, and suggest that the activity of myosin-V may be regulated by proteins or lipids on the vesicle surface.

A 3-month, double-blind, controlled trial of feeding with sucrose polyester in human volunteers

Sucrose polyester (SPE) is a tasteless, odourless substance which reduces plasma cholesterol concentrations and may therefore be valuable as a fat substitute in human foodstuffs. It has recently been approved for use in snack foods by the United States Federal Drug Administration. The current study was designed to investigate its effects on gastrointestinal physiology and nutrient absorption in human subjects. A 6-month (2 x 3-month periods) double-blind, placebo-controlled, randomized, cross-over trial of SPE and control fat was performed in healthy free-living volunteers. Subjects consumed 20-40 g of SPE daily (mean 26.8 (SE 6.8) g) which reduced the intake of total and saturated fat but had no effect on energy intake or body weight. Plasma cholesterol and triacylglycerols were reduced. The frequency of bowel movements and their urgency were increased and anal leakage occurred in 7.2% of subjects. Abdominal pain was more frequent in subjects receiving SPE and was significantly greater than in the control group after 8 weeks feeding. The plasma concentrations of vitamin E and six carotenoids were significantly reduced. Routine haematology and biochemistry, other vitamins, intestinal biopsies, bile-salt retention, rectal prostaglandins, fractional Ca absorption and aminopyrine metabolism were unaffected. The ingestion of foods containing 20-40 g SPE daily provoked significant gastrointestinal problems. This intake is greater than that to be expected from the use of SPE in savoury snack foods, for which it has been approved by the United States Federal Drug Administration. However, the favourable effects on lipid profiles must be balanced against the reduction in the concentrations of vitamins and carotenoids, as these compounds may have beneficial effects on health through protection from free-radical oxidative stress.

Smoking, hemorheologic factors, and progression of peripheral arterial disease in patients with claudication

PURPOSE

The purpose of the current study was to determine whether hemostatic and rheologic factors are associated with the deterioration of peripheral arterial disease in patients with intermittent claudication and the influence of smoking and severity of underlying disease on these relationships.

METHODS

We conducted a prospective cohort study with a 6-year follow-up period of a consecutive series of 607 patients with uncomplicated intermittent claudication. The study setting was the Peripheral Vascular Clinic, Royal Infirmary of Edinburgh. The main outcome measures were peripheral vascular intervention or onset of severe chronic leg ischemia (rest pain, ulceration, gangrene).

RESULTS

A total of 210 patients died during follow-up. Two hundred three patients did not have a vascular event or deterioration of limb ischemia, 45 patients underwent a peripheral vascular intervention, and 64 progressed to severe chronic leg ischemia. Median levels (interquartile ranges) of whole blood viscosity were significantly higher in the vascular intervention group (3.75 mPa/sec; range, 3.38 to 4.13 mPa/sec) than in those who did not deteriorate 3.48 mPa/sec; range, 3.06 to 3.83 mPa/sec) (p < or = 0.05), and plasma von Willebrand factor was higher in those with severe chronic leg ischemia (154.0 IU/dl; range, 122.0 to 187.0 IU/dl) than in those who did not deteriorate (131.0 IU/dl; range, 106.0 to 165.0 IU/dl) (p < or = 0.01). After adjustment for age, sex, cigarette smoking, and ankle brachial pressure index, the levels of plasma fibrinogen and blood and plasma viscosities were each associated with an increased risk of vascular intervention (all p < or = 0.05). There were no significant associations between any of the hemorheologic factors and the risk of severe chronic leg ischemia on multivariate analyses.

CONCLUSION

Elevations in rheologic factors may have important effects on further reduction of blood flow in the legs of patients with claudication and promote worsening ischemia and clinical progression of symptoms.

Escape from vasopressin-induced antidiuresis: role of vasopressin resistance of the collecting duct

Previously, we demonstrated that escape from vasopressin-induced antidiuresis ("vasopressin escape") in rats is associated with a large, selective decrease in whole kidney expression of aquaporin-2, the vasopressin-regulated water channel. Here, we show that isolated perfused inner medullary collecting ducts (IMCDs) from vasopressin-escape rats desamino-[D-arginine]vasopressin (DDAVP)/water-loaded have dramatically reduced vasopressin-dependent osmotic water permeabilities [46% of control rats (DDAVP alone)], which coincides with a fall in inner medullary aquaporin-2 protein abundance as measured by immunoblotting in the opposite kidney. Furthermore, we demonstrate in IMCD suspensions that cAMP accumulation in response to DDAVP is substantially reduced in the vasopressin-escape rats both in the presence and absence of the phosphodiesterase inhibitor IBMX. By immunoblotting, we show that the abundance of two proteins important in cAMP generation: the stimulatory heterotrimeric G protein subunit Gs and adenylyl cyclase type VI, do not change. We conclude that vasopressin escape is associated with relative vasopressin resistance of the collecting duct cells manifested by decreased intracellular cAMP levels. The decreased cAMP levels can contribute to the demonstrated decrease in collecting duct water permeability in two ways: 1) by causing a decrease in aquaporin-2 expression and 2) by limiting the acute action of vasopressin to increase collecting duct water permeability.

Mathematical modelling of the release of drug from porous, nonswelling transdermal drug-delivery devices

A general model is presented for the release of drug from porous nonswelling, transdermal drug-delivery devices and it is shown to reduce to previously proposed models in suitable limits. The processes which govern the release of drug are considered to be diffusion of dissolved drug and dissolution of dispersed drug, both in the body of the device and in the device pores, and transfer of drug between the two domains. In the classical limit of large dissolution rates, the problem reduces to one of the moving-boundary type, and solution of this problem in the case where the initial drug loading is much greater than the drug solubility in the device yields expressions for the flux of drug to a perfect sink (modelling in vitro conditions). It is shown that behaviour greatly differing from the classical first-order drug delivery (alpha t 1/2) may be exhibited, depending upon the parameter regime. In some situations the dissolution rates may not be so large and solutions of the general model are derived in the case where the dispersed drug is considered to be undepleted and the diffusivity in the solvent-filled pores is much larger than in the body of the delivery device. Numerical studies are undertaken, and the coupling of delivery device and skin-diffusion models (in order to model the complete transdermal drug-delivery process) is also considered.

The dispersions of estimates of sensitivity obtained from four psychophysical procedures: implications for experimental design

The dispersions of estimates of sensitivity obtained from the yes-no, two-alternative forced-choice (2AFC), matching-to-sample, and same-different tasks were examined to determine which task would be more appropriate to use in a given experimental context. Consideration was given to the effects of corrections for extreme sampled proportions. These corrections result in biased estimators, and hence the mean-square deviation of the sampled values about the population mean [MSD(d')], rather than that about the mean of the estimates [VAR(d')], indicates more completely the extent of the error in the estimator. For barely discriminable events (d' approximately equal to 0.5), the yes-no and 2AFC tasks had the lowest values of MSD(d'). However, for very discriminable events(d > 3), the same-different and matching-to-sample tasks had lower values of MSD(d').

Blood viscosity and elevated carotid intima-media thickness in men and women: the Edinburgh Artery Study

BACKGROUND

Several hemostatic and rheological factors have been associated with incident cardiovascular events. However, there have been no reports on the relationship of rheological factors with early atherosclerosis and very few on hemostatic factors. We therefore studied the relationship between these factors and carotid intima-media thickness (IMT).

METHODS AND RESULTS

The Edinburgh Artery Study measured fibrinogen, tissue plasminogen activator (tPA), fibrin D-dimer, von Willebrand factor (vWF), blood and plasma viscosities, and hematocrit as part of its baseline examination during 1988-1989. At the 5-year follow-up, valid measurements of IMT had been recorded in 1106 men and women 60 to 80 years old. In men, blood viscosity (P< or =.001) and its major determinants, plasma viscosity, fibrinogen (both P< or =.01), and hematocrit (P< or =.05), were all linearly related to IMT. Furthermore, blood viscosity, fibrinogen (both P< or =.01), and plasma viscosity (P< or =.05) remained significantly associated on multivariate analysis. Correcting blood viscosity to a standard hematocrit of 45% had little effect on its association. In men, there was a significantly increased risk of having an IMT above versus below the upper quartile of its distribution (1.05 mm) for SD increases in blood viscosity (P< or =.01), fibrinogen, corrected blood viscosity, and plasma viscosity (all P< or =.05). With the exception of plasma viscosity, these risks were unaffected by adjustment for other common cardiovascular risk factors. No significant associations were found between any of the hemorheological factors and IMT in women or for tPA, fibrin D-dimer, or vWF in either sex.

CONCLUSIONS

These findings suggest that in men, blood viscosity and its major determinants are associated not only with incident cardiovascular events but also with the early stages of atherosclerosis. This may be one explanation for the link between rheological factors and events.

Methane output and lactation response in Holstein cattle with monensin or unsaturated fat added to the diet

We measured effects of continuous vs twice-daily feeding, the addition of unsaturated fat to the diet, and monensin on milk production, milk composition, feed intake, and CO2-methane production in four experiments in a herd of 88 to 109 milking Holsteins. Methane and CO2 production increased with twice-daily feeding, but the CO2:CH4 ratio remained unchanged. Soybean oil did not affect the milkfat percentages, but fatty acid composition was changed. All saturated fatty acids up to and including 16:0 decreased (P < .01), whereas 18:0 and trans 18:1 increased (P < .001). The 18:2 conjugated dienes also increased (P < .01) when the cows were fed soybean oil. Monensin addition to the diet at 24 ppm decreased methane production (P < .01); the CO2:CH4 ratios reached 15, milk production increased (P < .01), and milkfat percentage and total milkfat output decreased (P < .01), as did feed consumption, compared with cows fed diets without monensin (P < .05). Milk fatty acid composition showed evidence of depressed ruminal biohydrogenation: saturated fatty acids (P < .05) decreased and 18:1 increased (P < .001); most of the increase was seen in the trans 18:1 isomer. As with soybean oil feeding, addition of monensin also increased (P < .05) the concentration of conjugated dienes. The monensin feeding trial was repeated 161 d later with 88 cows, of which 67 received monensin in the diet in the first trial and 21 cows were newly freshened and had never received monensin. Methane production again decreased (P < .05), but this time the CO2:CH4 ratio did not change and all other monensin-related effects were absent. The ruminal microflora in the cows that had previously received monensin seemed to have undergone some adaptive changes and no longer responded as before.

Haemostatic factors and prediction of ischaemic heart disease and stroke in claudicants

Thrombotic risk factors may be important in determining cardiovascular outcome in patients with symptomatic peripheral arterial disease. A cohort study with a 6-year follow-up period was established to determine the relationships between haemostatic and rheological factors and incident ischaemic heart disease (IHD) and stroke events in patients with peripheral arterial disease. A consecutive series of 607 patients with intermittent claudication was examined between 1989 and 1990 at the Peripheral Vascular Clinic, Royal Infirmary of Edinburgh. Main outcome measures were combined fatal and non-fatal stroke, non-fatal myocardial infarction (MI), coronary death and total coronary events. A total of 210 patients died during follow-up. 203 patients did not experience a vascular event or deterioration of limb ischaemia. Median levels of fibrinogen, von Willebrand factor (VWF), tissue plasminogen activator (t-PA) antigen, fibrin D-dimer and whole blood viscosity were significantly higher in those who experienced an event compared with those who did not. After adjusting for age and sex, fibrin D-dimer was significantly associated with risk of non-fatal myocardial infarction (RR 1.50, 95% CI 1.09-2.06, P < or = 0.01). Both fibrinogen and fibrin D-dimer were associated with risk of total coronary events (P < or = 0.05). The risk of stroke was related to baseline levels of t-PA antigen (RR 1.87, 95% CI 1.04-3.34, P < or = 0.05) and whole blood viscosity (RR 1.33, 95% CI 1.07-1.65, P < or = 0.01). All the relationships became weaker and statistically non-significant after further adjustment for cigarette smoking, systolic blood pressure, glucose and baseline IHD. The associations of these factors to IHD and stroke may therefore be partly related to cardiovascular risk factors, but are likely to be important in the pathogenesis of future atherothrombotic events in subjects with peripheral arterial disease.

Modulation of intracellular transport by transported proteins: insight from regulation of COPI-mediated transport

Intracellular transport is best understood for how proteins are shuttled among different compartments of the secretory pathway by membrane-bound transport carriers. However, it remains unclear whether regulation of this transport is modulated by the transported (cargo) proteins in the lumen of transport pathways. In the early secretory pathways that connect the endoplasmic reticulum (ER) and the Golgi complex, the small GTPase ADP-ribosylation factor 1 (ARF1) recruits a cytosolic coat protein complex named COPI onto membranes as a key step in the formation of transport vesicles. Transport of newly synthesized proteins that leave the ER includes a class of cargo proteins with a sequence motif of KDEL. When these KDEL proteins leave the ER to reach the Golgi complex, they are recognized by their receptor and transported retrograde in COPI-coated vesicles back to the ER. We now demonstrate that stimulation of the KDEL receptor by a KDEL protein enhances an interaction between the KDEL receptor and a GTPase-activating protein for ARF1. As a result, more cytosolic GTPase-activating protein is recruited to membranes to inactivate ARF1. Thus, the KDEL proteins are examples of luminal cargo proteins that regulate transport by activating their receptor. Most likely, this regulation affects retrograde transport from the Golgi complex to the ER, as activated KDEL receptor appears to reside only in retrograde COPI-coated vesicles.

Patterns of hepatitis G viraemia and liver disease in haemophiliacs previously exposed to non-virus inactivated coagulation factor concentrates

Hepatitis G virus (HGV), a novel flavivirus, has been implicated as a cause of posttransfusion hepatitis. We have performed a longitudinal study in a cohort of haemophiliacs (n = 68) who previously received non-virus inactivated coagulation factor concentrates to assess both patterns of HGV viraemia and any associated liver disease. Hepatitis C virus (HCV) RNA was present in 58/68 and co-infection with human immunodeficiency virus (HIV) was present in 15/68. HGV RNA was detected in 17/68 (25%) samples from the mid-1980s. There was no association between either HIV infection (p = 0.74) or co-infection with a particular HCV genotype (p = 0.62). However, there was a relationship between HGV viraemia and the severity of haemophilia (p = 0.0004) with HGV RNA detected in 5/19, 9/16 and 3/32 patients with mild, moderate and severe haemophilia respectively. A longitudinal study was performed in 15/17 haemophiliacs with HGV viraemia using stored serum samples from the 1980s and 1990s. HGV viraemia persisted in 8/15 and cleared in 7/15 over a variable period of time. A Weibull model was constructed to estimate the duration of HGV viraemia in the study group. The 75th and 90th percentiles for the duration of HGV were estimated to be 8.7 years (95%, confidence interval 4.8-15.7) and 23.6 years (95% confidence interval 11.8-47.1) respectively. Laparoscopic liver inspection/biopsy was performed in 25/68. There was no association between severity of liver disease and HGV viraemia (p = 0.43). This study demonstrates considerable variation in patterns of HGV viraemia in haemophiliacs. We found little evidence to implicate HGV as a major cause of chronic liver disease in haemophiliacs.

The role of rheological and haemostatic factors in hypertension

Research into the pathogenesis of hypertension has, in the past, tended to concentrate on changes in vascular geometry, cardiac output and blood volume. However, patients with hypertension are known to be at an increased risk of both coronary heart disease and cerebrovascular disease; complications which are thrombotic in origin. Since rheological and haemostatic factors are known to be involved in thrombogenesis, their potential role in the pathogenesis of patients with hypertension has received increasing attention. The purposes of this review are to update previous reviews and to summarise the relationship between hypertension, its complications and treatment and a range of haemorheological factors.

Steroid sex hormones and peripheral arterial disease in the Edinburgh Artery Study

Although treatment with high dose exogenous sex hormones affects cardiovascular risk, the role of physiological levels of endogenous sex hormones in the development of atherosclerotic disease in men and women is unknown. Forty men and 43 women wit peripheral arterial disease and 88 age- and sex-matched controls were selected from participants in the Edinburgh Artery Study, a random survey of 1592 men and women ages 55-74 years from the general population. Compared with sex-matched controls, male cases had higher systolic blood pressure (155.5 mmHg vs. 138.7 mmHg; p < or = 0.01) and waist hip ratio (0.92 vs. 0.89; p < or = 0.05) and female cases had higher lifetime smoking (square root of packyears 2.14 vs. 1.03; p < or = 0.05). Mean estrone levels were slightly higher in male cases than controls (101.9 pmol/Liter vs. 92.1 pmol/Liter; p = 0.09), but this association lost significance after multivariate adjustment for age and body mass index. Mean levels of total and free testosterone, estradiol, and sex hormone binding globulin were not significantly different in cases compared with controls in either sex (p > 0.1). These results, in accordance with previous prospective studies on coronary artery disease, do not support a role for physiological levels of endogenous sex hormones in the development of peripheral arterial disease in men or postmenopausal women.

Medicare treatment differences for blacks and whites

OBJECTIVES

This study investigated racial differences in procedure use among elderly Medicare beneficiaries. It is hypothesized that providers do not discriminate inappropriately in treating black and white patients and that the apparent differences in black-white treatment could be attributed to other differences between the two populations.

METHODS

Rates of use for selected procedures were examined among two patient groups: (1) the universe of Medicare beneficiaries in 10 states and the District of Columbia and (2) a subset of this sample created by matching beneficiaries on the basis of zip code of residence to neutralize the effects of black-white differences in provider access and regional practice patterns. Because all Medicare beneficiaries have a common core of standard benefits, the importance of financial access differences in accounting for black/white utilization differences is diminished.

RESULTS

Three major findings were indicated from this study: (1) area-controlled comparisons find even larger black-white disparities than those shown from uncontrolled comparisons, (2) the disparities are larger in southern states, and (3) the disparities vary substantially with procedure cost.

CONCLUSIONS

Although no clinical data were analyzed, providers appeared to be giving less intensive treatment to otherwise similar black Medicare beneficiaries.

Hemostatic factors as predictors of ischemic heart disease and stroke in the Edinburgh Artery Study

Plasma fibrinogen is a consistent predictor of ischemic heart disease (IHD) in prospective studies, but there are fewer data relating other hemostatic variables to IHD and also to stroke. We therefore studied the relationships of plasma fibrinogen, von Willebrand factor antigen, tissue plasminogen activator (TPA) antigen, factor VII, and fibrin D-dimer to incidence of IHD and stroke and determined whether any associations could be explained by conventional risk factors and baseline heart disease. In the Edinburgh Artery study, 1592 men and women aged 55 to 74 years, randomly sampled from the general population, were followed prospectively over 5 years to detect fatal and nonfatal IHD and stroke events. During the 5 years, 268 new vascular events were identified. Baseline plasma fibrinogen was independently related to risk of stroke in multivariate analysis that adjusted for cigarette smoking, LDL-cholesterol, systolic blood pressure, and preexisting IHD (relative risk [RR] 1.52, 95% confidence interval [CI] 1.17, 1.98). TPA antigen, and fibrin D-dimer were also independently associated with risk of stroke (RR 1.69,95% CI 1.22,2.35 and RR 1.96, 95% CI 1.12,3.41, respectively). Significant relationships were found between TPA antigen and myocardial infarction (P < or = .05). In older men and women, increased coagulation activity and disturbed fibrinolysis are predictors of future vascular events (both IHD and stroke).

Randomized controlled trial of antioxidants in intermittent claudication

Epidemiological evidence suggests that antioxidants protect against the development of atherosclerosis. To determine the effectiveness of antioxidant therapy in patients with lower limb atherosclerosis, a randomized placebo-controlled trial was performed in 120 men and women with intermittent claudication and an ankle/brachial pressure index (ABPI) < or = 0.9. The study was analysed on an intention-to-treat basis. After 2 years, there were no significant differences between antioxidant and placebo groups in plasma cholesterol, lipoproteins, haemostatic or rheological factors. However, after 6 months, low density lipoprotein cholesterol was significantly lower in those taking antioxidant (108.0 mg/dl compared with 120.1 mg/dl, p < 0.05). There were no differences in the ABPI or walking distance, although both groups improved slightly with time. The incidence of cardiovascular events and death was nonsignificantly lower in the antioxidant compared with the placebo group: event rates per year were 5.5% (95% CI 2.4-8.6) in the first year and 9.6% (95% CI 6.8-12.4) in the second year for those on antioxidants; and 7.7% (95% CI 5.1-10.3) and 13.3% (95% CI 8.9-17.7) respectively for those on placebo. Significantly fewer serious adverse events occurred in the antioxidant than the placebo group: 21.8% (95% CI 16.2-27.4) compared with 40.0% (95% CI 33.9-46.1). This study therefore suggests that although antioxidants may prevent cardiovascular events in patients with peripheral atherosclerosis, they do not improve lower limb function.

The role of financial incentives in shaping clinical practice patterns and practice efficiency

The US healthcare system is evolving from one in which most providers have been paid on some variation of a fee-for-service basis to one in which many or most providers will be paid on a capitated basis. Will this change in financial incentives make a difference in how coronary artery disease and heart failure are treated and managed? Although the evidence is equivocal and limited, two recent studies suggest that capitation and other global payment incentives may dramatically alter clinical practice patterns in treating cardiovascular disease and substantially reduce cardiac-care costs. Clinical cost-effectiveness research efforts must be intensified. Thought leaders in the field of cardiology must move forcefully in developing, disseminating, and encouraging cardiac-care providers to accept and implement evidence-based clinical practice guidelines. The alternative may be ill-advised tradeoffs decided in a decentralized, competitive marketplace, with algorithms being developed de facto by individual practitioners or groups in response to capitated reimbursement constraints. The resulting practice could reduce healthcare use and spending without being cost-effective. Unexpected and undesirable health outcomes could ensue.

Cardiovascular risk factors for early carotid atherosclerosis in the general population: the Edinburgh Artery Study

BACKGROUND

Recent attempts to identify cardiovascular risk factors affecting early-stage carotid atherosclerosis, measured by ultrasonographically assessed intima-media thickness, have been inconclusive.

OBJECTIVE

To study the relationship between traditional cardiovascular risk factors and intima-media thickness.

METHODS

Ultrasonic evaluation of the intima-media thickness of the common carotid artery was included in the 5-year follow-up examination of participants of the Edinburgh Artery Study. We had valid readings of intima-media thickness for 1106 men and women aged 60-80 years. Information on a range of cardiovascular risk factors had been collected during the baseline examination.

RESULTS

For men, in addition to age, lifetime smoking (measured in terms of pack years) was the only cardiovascular risk factor associated with increased intima-media thickness (P< or = 0.01) in the univariate analysis. Both systolic blood pressure (P < or = 0.001) and the high-density lipoprotein (HDL: total cholesterol ratio (P < or = 0.01) were correlated with intima-media thickness for women. When all the variables had been included in a multivariate analysis, pack years of smoking and the HDL:total cholesterol ratio were associated with early atherosclerotic development in men. In an equivalent analysis for women, alcohol consumption, systolic blood pressure and the HDL:total cholesterol ratio were associated with intima-media thickness.

CONCLUSION

These data suggest that risk factors affecting intima-media thickness differ for men and women. Further sex-specific analyses of prospective population studies are required in order to clarify the role of 'traditional' cardiovascular risk factors in the early stages of carotid atherosclerosis.

Is intermittent claudication improved by percutaneous transluminal angioplasty? A randomized controlled trial

PURPOSE

Percutaneous transluminal angioplasty (PTA) is an increasingly popular invasive treatment for peripheral arterial disease, but there have been very few controlled trials to justify its use. This randomized controlled clinical trial was performed to determine in patients with mild and moderate intermittent claudication differences in outcome between PTA and conventional medical treatment after 2 years.

METHODS

Six hundred patients with claudication were screened at the Peripheral Vascular Clinic, Royal Infirmary of Edinburgh. Sixty-two patients with short femoral artery stenoses or occlusions (47 patients) and iliac stenoses (15 patients) were randomized to either PTA plus medical treatment (PTA group, 30 patients) or to medical treatment alone (control group, 32 patients). Medical treatment consisted of daily low-dose aspirin and advice on smoking and exercise. Outcome measures studied were patient-reported maximum walking distance, exercise treadmill distance until onset of claudication, treadmill maximum walking distance, ankle-brachial pressure index (ABPI), quality of life (Nottingham Health Profile), and duplex ultrasound-measured extent of occlusive disease.

RESULTS

At 2 years of follow-up, the PTA group and control subjects did not differ significantly in patient-reported maximum walking, treadmill onset to claudication, treadmill maximum walking distances, or ABPI (p > 0.05). However, the PTA group had significantly fewer occluded arteries (p = 0.003) and a lesser degree of stenosis (expressed in terms of the velocity ratio; p = 0.004) in patent arteries. Quality of life was not demonstrably different between the two groups (p > 0.05).

CONCLUSIONS

Two years after PTA, patients had less extensive disease than medically treated patients, but this did not translate into a significant advantage in terms of improved walking or quality of life. There are important implications for patient management and future clinical research.

Submissiveness and protection from coronary heart disease in the general population: Edinburgh Artery Study

BACKGROUND

Type A behaviour and, more specifically, hostility and anger have been associated with increased risk of coronary heart disease (CHD). But less attention has been paid to other features of personality. Our aim was to assess whether a submissiveness trait, which is independent of hostility, was related to future risk of CHD in the general population.

METHODS

The Edinburgh Artery Study is a cohort study of a random sample of 809 men and 783 women aged 55 to 74 years. At the baseline examination in 1988, we administered the Bedford-Foulds Personality Deviance Scales. The participants were followed up for 5 years for cardiovascular events. Criteria to define events were adapted from the American Heart Association. Events were ascertained from the information and Statistics Division of the Scottish Office Home and Health Department, general practitioners, the UK National Health Service Central Register, annual questionnaires to the participants, and the second examination at the end of follow-up.

FINDINGS

During follow-up, 57 (7.0%) men and 28 (3.6%) women had non-fatal myocardial infarctions; 25 (3.1%) men and 8 (1.0%) women had fatal myocardial infarctions; and 48 (5.9%) men and 41 (5.2%) women developed angina pectoris. We found that mean submissiveness scores were significantly higher in men and women who did not have a non-fatal myocardial infarction than in those who did (18.88 [SE 0.15] vs 17.70 [0.40], p = 0.023 in men; 20.76 [0.17] vs 18.18 [0.86], p = 0.002 in women). In multiple logistic-regression models, submissiveness remained independently associated with risk of myocardial infarction in women only; a decreased risk of both non-fatal myocardial infarction (relative risk 0.59 [95% CI 0.40-0.85]) and, to a lesser extent, total myocardial infarction (0.69 [0.27-0.96]), was associated with an increase of 1 SD in submissiveness.

INTERPRETATION

The personality trait of submissiveness may be protective against non-fatal myocardial infarction, particularly in women. A better understanding is required of the complicated effects of personality on CHD development.

Selective amplification of T-cell receptor variable region species is demonstrable but not essential in early lesions of psoriasis vulgaris: analysis by anchored polymerase chain reaction and hypervariable region size spectratyping

Several groups have investigated the role of T cells in the pathogenesis of psoriasis by determination of T-cell receptor (TCR) B-chain variable (V) region usage, both in chronic plaque (psoriasis vulgaris) and guttate forms, with various results. Because there are no data on TCR expression in early psoriasis vulgaris, when specific cellular immune events may be expected to be most pronounced, we have analyzed early lesions (less than 3 wk old) of ten patients, with highly reproducible results. We have developed a highly controlled anchored polymerase chain reaction (PCR) method in which TCR beta chain species are all amplified with the same primer pair and products are quantified by dot blot hybridization with BV family-specific oligonucleotide probes. Overexpression of certain TCR BV genes was observed in the majority of lesional biopsies, but in samples in which the expanded BV family formed more than 10% of total lesional BV (half of the samples analyzed), BV2 and BV6 predominated. The consistency of overexpression of these BV species between patients was much less than in previous studies of TCRBV usage in established chronic plaque psoriasis lesions. Complementarity-determining region 3 (CDR3) size spectratyping demonstrated evidence for selective clonal T cell accumulation in less than half of the lesional samples showing BV expansion. These results indicate that selective amplification of TCRBV species occurs in early psoriasis vulgaris but is not essential to the pathogenic process and may be more important in the maintenance or expansion of chronic lesions.

Re-using data from case-control studies

Despite its ability to maximize statistical power while keeping data collection costs to a minimum, case-control sampling provides a non-representative sample of the population. When fitting a logistic regression model to data obtained in such a study, using the variable stratifying the population as the response, it is well known that the estimate of the constant term will be biased, but those of the coefficients of the covariates will not. However, subsequent to the case-control study, it is often desired to conduct a secondary analysis, using a variable that was previously a covariate in the main study as the response. If this new response is associated with the original variable used to stratify the population into cases and controls, a conventional logistic regression analysis will usually result in biased estimates of all the regression coefficients, not just the constant. This situation has recently been studied by Nagelkerke et al. who describe some situations where no bias occurs. In this paper we discuss how to calculate maximum likelihood estimates of all the regression coefficients, in the situation where the sampling rates for cases and controls are known. An example using data from the New Zealand Cot Death Study is presented.

Influence of players' physique on rugby football injuries

OBJECTIVES

To determine whether there is an association between a player's physique and injuries incurred while playing rugby football.

METHODS

A cohort study was carried out involving all senior rugby clubs in the Scottish Borders during the 1993-1994 rugby season. Somatotype estimates were determined for 1152 (95%) of the 1216 eligible players. Body mass index (BMI), chest to waist ratio, and the ponderal index (PI) were used to classify players' physique as endomorphic (obese), mesomorphic (muscular), and ectomorphic (linear).

RESULTS

A strong association was found between physique and age (chi 2 test: chi 2 = 317.2, df = 10, P < 0.0001). More younger players were ectomorphs. Older players were more often endomorphic. The physiques of forwards and backs were significantly different (chi 2 test: chi 2 = 58.6, df = 2, P < 0.0001), with forwards being of a heavier build than three-quarters, even after adjustment for age. Endomorphic players were more likely than ectomorphs to be injured in a match after adjustment for age (age-adjusted mean BMI for players who were injured in a match was 25.4 compared with 24.6 for players who were not injured in a match, P < 0.0001; adjusted chest to waist ratio means were 1.136 and 1.125 respectively, P = 0.0307; adjusted PI means were 0.414 and 0.417 respectively, P = 0.0056). Increased risk of injury may occur when players play out of position, since one fifth of all injuries occurred in this circumstance.

CONCLUSIONS

Further research needs to be conducted using a more objective method of measuring somatotype on a further cohort of players so that the risk of injury for different body types can be examined more closely and related to other potential confounding factors. The level of increased risk for individuals playing out of their usual playing position needs to be established with a greater degree of certainty.

Trimethoprim/sulfamethoxazole-induced hypoglycemia in a patient with acute renal failure

OBJECTIVE

To report a case of trimethoprim/sulfamethoxazole (TMP/SMX)-induced hypoglycemia in a patient with acute renal failure.

DATA SOURCES

English-language references identified via a MEDLINE search from January 1966 to August 1996 and a bibliographic review of pertinent articles.

DATA SYNTHESIS

Similar to sulfonylureas, sulfonamides are thought to cause hypoglycemia by increasing pancreatic secretion of insulin. To date, nine cases of TMP/SMX-induced hypoglycemia have been reported in the literature. This case represents the second report in which a patient experienced TMP/SMX-induced hypoglycemia that resolved after the dosage was adjusted for the patient's decreased renal function. This case involved a 73-year-old comatose white man initiated on high-dose TMP/SMX for nosocomial pneumonia caused by Stenotrophomonas maltophilia. After 5 days of therapy, the patient presented with severe hypoglycemia that persisted over 8 hours despite multiple intravenous bolus doses and infusions of dextrose. The patient had several risk factors that may have compounded his risk for hypoglycemia, including food deprivation and acute renal failure. After management with dextrose and dose adjustment of the patient's TMP/SMX regimen according to renal function, the hypoglycemia resolved.

CONCLUSIONS

TMP/SMX may cause reversible hypoglycemia that may be prolonged (approximately 12 h), particularly in patients with risk factors for hypoglycemia. Common risk factors include compromised renal function, prolonged fasting conditions, malnutrition, and the use of excessive doses. Patients with these risk factors should be monitored closely and, more importantly, initiated on a dosing regimen adjusted for renal impairment.

Factors contributing to practice variation in post-stroke rehabilitation

OBJECTIVE

To analyze geographic variability in the utilization and cost of post-stroke medical care using multiple linear regression.

DATA SOURCES/STUDY SETTING

A 20 percent random sample of Medicare beneficiaries with an admission to an acute care hospital for stroke during the first six months of 1991, supplemented by data from their Medicare claims and beneficiary records, the Medicare Cost Reports for hospitals and nursing homes, and the Area Resource File.

STUDY DESIGN

Weighted least squares regression is used to analyze variations in post-stroke practice patterns across 151 MSAs (Metropolitan Statistical Areas). Average post-stroke costs, utilization rates, and facility lengths of stay are regressed on patient and market characteristics.

DATA COLLECTION/EXTRACTION METHODS

For a six-month post-stroke interval, beneficiary-level post-stroke costs and service utilization are averaged by MSA. Variables describing market conditions are then added to these MSA-level records.

PRINCIPAL FINDINGS

Patient variables rarely explain more than a third of practice variation, and often they explain substantially less than that. Market variables (with some exception) tend to be relatively less important. Finally, one-half to two-thirds of the practice variation across MSAs is unexplained by the patient and market factors measured in our data.

CONCLUSIONS

A substantial portion of inter-MSA variability in utilization and intensity of post-stroke rehabilitation services cannot be explained by differences in patient characteristics. Given the large practice differences observed across MSAs, it seems unlikely that unmeasured patient differences can account for much more of the practice differences.

Neuropsychological functioning following fetal striatal transplantation in Huntington's chorea: three case presentations

Neurotransplantation has been proposed as a potential treatment for the neurodegenerative disorder of Huntington's disease (HD), which currently has no effective therapy. While patients with Parkinson's disease have received neurotransplantation, until recently no HD patients have undergone transplantation for HD with standardized evaluations of their progress following surgery. The current report presents the cognitive changes in three patients with HD who underwent bilateral transplantation of human fetal striatal tissue. As part of the pre- and postsurgical evaluation, all three patients were administered a neuropsychological battery sensitive to the cognitive effects of HD within 2 mo prior to surgery and at 4-6 mo following transplantation. Four to 6 mo subsequent to surgery, all patients demonstrated increased scores on some measures of cognitive functioning. However, the pattern of changes was not uniform across subjects. These findings suggest that fetal striatal transplantation may improve some of the cognitive symptoms associated with HD in the three reported patients.

Hostility, cigarette smoking and alcohol consumption in the general population

Hostility has been associated with coronary heart disease, and hostility may affect coronary risk through its influence on risk factors such as cigarette smoking and alcohol consumption. The objective of this study was to determine relationships between hostile personality, cigarette smoking and alcohol consumption in the general population. The Edinburgh Artery Study comprises a cross-sectional survey of 1592 men and women aged 55-74 years sampled from age-sex registers of 10 general practices throughout the city. The Bedford-Foulds Personality Deviance Questionnaire was used to elicit extrapunitiveness (including hostile thoughts), dominance (including hostile acts) and intropunitiveness. Social class, age and deprivation score were controlled for in multivariate analyses. The hostile thoughts scale emerged as a significant independent predictor of alcohol consumption in men and women (P < or = 0.01), and the models accounted for 4-9% of the variance in alcohol consumption. Hostile acts were independently predictive of smoking in men (P < or = 0.001), with the model accounting for 5% of the variance in smoking. Hostile thoughts were independently predictive of smoking in women (P < or = 0.001), and the model accounted for 4% of the variance in their smoking. We conclude that hostility may affect coronary risk through its influence on lifestyle-related coronary risk factors, although in future further elucidation of hostility type and standard measurement of hostility are necessary.

Smoking, atherosclerosis and risk of abdominal aortic aneurysm

AIMS

The role of cardiovascular risk factors and atherosclerosis in the aetiology of abdominal aortic aneurysms is not well understood. The aim of this study was to determine the association between atherosclerosis and aortic aneurysm in the general population and the extent to which cardiovascular risk factors might increase the risk of aneurysm independently of an effect on atherosclerotic disease.

METHODS AND RESULTS

In the Edinburgh Artery Study, 1592 men and women aged 55-74 years were followed prospectively over a period of 5 years. Forty subjects were identified as having an abdominal aortic aneurysm and, for each, five controls were randomly selected. Case showed a higher prevalence of cardiovascular disease (P < or = 0.001) and had a lower ankle brachial pressure index (P < or = 0.01). Current and recent ex-cigarette smokers had an increased risk of aortic aneurysm compared with long time ex-smokers and never smokers (odds ratio 3.08, 95% CI 1.53 to 6.21). Adjustment for concurrent atherosclerotic disease reduced the odds ratio to 2.63 (95% CI 1.26 to 5.45). The risk of aortic aneurysm was not related to elevation in diastolic blood pressure or in serum cholesterol.

CONCLUSIONS

These findings indicate that atherosclerotic disease is associated with risk of aortic aneurysm in the general population. In addition, cigarette smoking appears to have a direct effect on the risk of aortic aneurysm which is independent of atherosclerosis.

Impact of angioplasty and arterial reconstructive surgery on the quality of life of claudicants. The Scottish Vascular Audit Group

Claudicants usually die from concomitant conditions. Therefore, surgical interventions are aimed at improving quality of life, rather than survival. This study compared the impact of percutaneous transluminal angioplasty (PTA), arterial reconstruction and conservative management on quality of life. SF36 questionnaires were completed by 201 newly referred claudicants prior to treatment and six months later. Multiple regression was used to compare the quality of life scores following the three treatments after adjustment for baseline scores, age, sex, site of disease and disease severity. Follow-up data were available on 81% of the 195 patients alive. Nineteen (10%) of these had undergone PTA and 19 (10%) reconstruction. All aspects of quality of life deteriorated following conservative treatment. PTA and arterial reconstruction produced significant improvements in both pain and physical functioning after adjustment for case-mix. Although unlikely to improve survival, PTA and arterial reconstruction are associated with significant improvements in quality of life.

Indications for arterial reconstruction and major amputation in the management of chronic critical lower limb ischaemia. The Scottish and Northern Vascular Audit Groups

OBJECTIVES

The aim of this study was to derive specific clinical indications for surgery in patients with chronic critical lower limb ischaemia and to determine the extent to which practice in Scotland conformed to these indications.

DESIGN, MATERIALS AND METHODS

Consensus on indications was achieved using a modified Delphi method in which a postal questionnaire was completed by 29 vascular surgeons on two occasions, with feedback between the rounds. Respondents indicated the appropriateness of arterial reconstruction and primary major amputation for 218 case scenarios comprising all possible combinations of clinical and angiographic findings.

RESULTS

Agreement was reached on 31 appropriate indications for major amputation and 65 for arterial reconstruction. In 10 hospitals in Scotland, 400 primary amputation and arterial reconstruction operations were reviewed retrospectively and compared with the indications. The clinical findings for 7 (4%) arterial reconstructions and 48 (24%) major amputations did not conform to the indications agreed by the Delphi method. The proportion of operations conforming to the agreed indications differed significantly by size of unit (p < 0.025).

CONCLUSIONS

This study shows that consensus can be reached on indications for surgery. However, in practice some operations performed do not conform with these indications. This discrepancy may be due to inappropriate practice.

The interplay of feeding and genetics on heifer rearing and first lactation milk yield: a review

Weight gain of young dairy replacement heifers, even over several months, is highly variable, lowly heritable, and a poor indicator of either weight at calving or first lactation milk yield. Voluntary forage consumption is much less variable, more heritable, and a better predictor of weight at calving and milk yield. Weight at calving is highly heritable but not correlated genetically with milk yield. Heavier weight at first calving due to feeding and management does increase milk yield. When grain is fed according to milk yield, weight loss during the first month or two after calving and milk yield are under strong genetic control and tightly genetically correlated to each other and to energy intake. The feed to milk ratio is managementally determined. Better-grown heifers eat more forage and can tolerate more grain consumption without digestive or metabolic disorders. Good body condition at calving seems essential for high milk yield. Genetic ability to mobilize body condition to increase milk yield justifies more grain and results in greater total efficiency up to the point of causing digestive disorders. Good heifer rearing is essential to high milk yield and feed efficiency. Realizing genetic potential for high yield demands excellence of feeding and management during lactation.

The conformational change responsible for AT1 receptor activation is dependent upon two juxtaposed asparagine residues on transmembrane helices III and VII

A model of the angiotensin AT1 receptor and site-directed mutagenesis were used to identify key residues involved in ligand binding. Receptors were stably expressed in human embryonic kidney 293 cells, and their binding properties compared. Wild type receptors exhibited low and high affinity binding sites for peptides. Substitution of Asn111, situated in the third transmembrane helix, resulted in a significant alteration in ligand binding with only high affinity binding of the peptides, angiotensin II, angiotensin III, and [p-amino-Phe6]angiotensin II and a marked loss in the binding affinity of the AT1 receptor selective non-peptide antagonist losartan. From our model it was apparent that Asn111 was in close spatial proximity to Asn295 in the seventh transmembrane helix. Substitution of Asn295, produced identical changes in the receptor's pharmacological profile. Furthermore, the Ser111AT1A and Ser295AT1A mutants did not require the association of a G-protein for high affinity agonist binding. Finally, the Ser295AT1A mutant maintained higher basal generation of inositol trisphosphate than the wild type, indicating constitutive activation. We propose that substitution of these residues causes the loss of an interaction between transmembrane helices III and VII, which allows the AT1 receptor to "relax" into its active conformation.

Relationship between carotid intima-media thickness and symptomatic and asymptomatic peripheral arterial disease. The Edinburgh Artery Study

BACKGROUND AND PURPOSE

Ultrasonic evaluation of intimamedia thickness (IMT) is one method of assessing the development of early atherosclerosis. This report describes the distribution of IMT within the general population and is one of the first to investigate its association with noninvasively assessed symptomatic and asymptomatic peripheral arterial disease.

METHODS

Ultrasonic evaluation of IMT was included in the 5-year follow-up examination of participants of the Edinburgh Artery Study. Valid readings of IMT were recorded in 1106 subjects aged 60 to 80 years, and the maximum from the right and left sides of the neck was used in the analysis. Existing symptomatic and asymptomatic peripheral arterial disease and coronary heart disease were also assessed at follow-up using previously validated noninvasive techniques.

RESULTS

IMT increased continuously with age (P < or = .01), and its distribution was positively skewed in both sexes. The results suggest that levels of atherosclerotic development in the common carotid artery are 5 to 10 years more advanced in men than in women. In this population, the overall prevalence of moderate to severe disease was very low (only 1.2% of study participants had IMT values > 2 mm). The presence of symptomatic (intermittent claudication) or asymptomatic (ankle brachial pressure index < or = 0.9) peripheral arterial disease was significantly associated with increased IMT (P < or = .05).

CONCLUSIONS

Although the prevalence of advanced atherosclerosis was very low, small changes in IMT were associated with clinically significant development of atherosclerosis in the peripheral arteries. However, further longitudinal studies are needed that standardize measurement techniques and would allow accurate comparisons across studies.

Impact of Medicare SELECT on cost and utilization in 11 states

In this article, the authors evaluate the cost and utilization effects of the SELECT implementations in 11 States. In particular they compare the before-and-after enrollment experiences of Medicare beneficiaries newly enrolled in SELECT plans with the experiences of those newly enrolled in traditional medigap plans. Using Medicare claims data for 1991 through 1994, the authors find that Medicare SELECT increased costs in five States, decreased costs in three States, and had no effect in three States. Cost increases were generally related to Part B utilization.

Blood viscosity and risk of cardiovascular events: the Edinburgh Artery Study

We examined the relationships of whole blood viscosity and its major determinants to incident cardiovascular events (ischaemic heart disease and stroke) in a prospective study of a random population sample of 1592 men and women aged 55-74 years (the Edinburgh Artery Study). 272 fatal and non-fatal cardiovascular events occurred during 5 years of follow-up (cumulative incidence 17.1%). Age and sex adjusted mean levels of blood viscosity (3.70 v 3.55 mPa.s), haematocrit (46.2 v 45.7%), haematocrit-corrected blood viscosity (3.57 v 3.48 mPa.s), plasma viscosity (1.35 v 1.33 mPa.s) and fibrinogen (2.88 v 2.67 g/l) were significantly higher in subjects who experienced events than in subjects who did not. The relationships of these rheological variables to cardiovascular events were at least as strong as those of conventional risk factors (smoking habit, diastolic blood pressure, and low-density lipoprotein cholesterol). After adjustment for these conventional risk factors, the associations of blood viscosity and haematocrit remained significant for stroke, but not for total events; whereas the associations of plasma viscosity and fibrinogen remained significant for total events and for stroke. These findings suggest that increased blood viscosity may be one plausible biological mechanism through which increases in haematocrit and fibrinogen may promote ischaemic heart disease and stroke. Randomized controlled trials of viscosity reduction in the prevention of cardiovascular events (e.g. by lowering high levels of haematocrit or plasma fibrinogen) are suggested.

Use of ankle brachial pressure index to predict cardiovascular events and death: a cohort study

OBJECTIVE

To determine whether a low ankle brachial pressure index is associated with an increased risk of cardiovascular events and death, and whether the prediction of such events could be improved by including this index.

DESIGN

Cohort study.

SETTING

11 practices in Edinburgh, Scotland.

SUBJECTS

1592 men and women aged 55-74 years selected at random from the age-sex registers of 11 general practices and followed up for 5 years.

MAIN OUTCOME MEASURES

Incidence of fatal and non-fatal cardiovascular events and all cause mortality.

RESULTS

At baseline 90 (5.7%) of subjects had an ankle brachial pressure index < or = 0.7, 288 (18.2%) had an index < or = 0.9, and 566 (35.6%) < or = 1.0. After five years subjects with an index < or = 0.9 at baseline had an increased risk of non-fatal myocardial infarction (relative risk 1.38, 95% confidence interval 0.88 to 2.16), stroke (1.98, 1.05 to 3.77), cardiovascular death (1.85, 1.15 to 2.97), and all cause mortality (1.58, 1.14 to 2.18) after adjustment for age, sex, coronary disease, and diabetes at baseline. The ability to predict subsequent events was greatly increased by combining the index with other risk factors--for example, hypertensive smokers with normal cholesterol concentrations had a positive predictive value of 25.0%, increasing to 43.8% in subjects with a low index and decreasing to 15.6% in those with a normal index.

CONCLUSION

The ankle brachial pressure index is a good predictor of subsequent cardiovascular events, and improves on predictions by conventional risk factors alone. It is simple and accurate and could be included in routine screening of cardiovascular status.

Hyperinsulinaemia: a risk factor for peripheral arterial disease in the non-diabetic general population

BACKGROUND

Peripheral arterial disease is a common complication of diabetes mellitus, and hyperinsulinaemia has been associated with an increased incidence of intermittent claudication in diabetic subjects. Our aim was to investigate the relationship between hyperinsulinaemia and peripheral arterial disease in the non-diabetic general population.

METHODS

Eighty-three cases with peripheral disease and 88 age- and sex-matched controls were selected from non-diabetic participants in the Edinburgh Artery Study, a survey of 1,592 men and women aged 55-74 years of randomly selected from the general population.

RESULTS

Mean plasma insulin, 1 h after a 75 g oral glucose load, was higher in cases than in controls (73.6 versus 59.8 mU/l; P < 0.05). The relationship between insulin and disease was independent of blood pressure [odds ratio (OR) 2.04; 95% CI 1.11-3.74; P < or = 0.05] and partially independent of low- and high-density lipoprotein cholesterol and triglycerides (OR 1.86; 95% CI 0.99-3.48; P < or = 0.1). Mean 1 h insulin was higher in current or ex-smokers than in those who had never smoked (P < or = 0.05) and when smoking was added to the multivariate model, the relationship between insulin and disease diminished (OR 1.64; 95% CI 0.83-3.23; P > 0.1).

CONCLUSIONS

In the non-diabetic general population, peripheral arterial disease is associated with post-glucose hyperinsulinaemia, independently of blood pressure, lipoproteins and triglycerides. Some of this association may be mediated by a relationship between hyperinsulinaemia and smoking.

Incidence, natural history and cardiovascular events in symptomatic and asymptomatic peripheral arterial disease in the general population

BACKGROUND

Intermittent claudication is associated with a poor prognosis, but less is known of the risks associated with asymptomatic peripheral arterial disease. The aims of this study were to determine the incidence and natural history of claudication, and the incidence of cardiovascular events in symptomatic and asymptomatic peripheral arterial disease.

METHODS

In 1988, 1592 subjects aged 55-74 years were selected randomly from the age-sex register of 10 general practices in Edinburgh, Scotland. The presence of peripheral arterial disease was determined by the World Health Organization questionnaire on intermittent claudication, the ankle brachial pressure index and a reactive hyperaemia test. This cohort was followed prospectively over 5 years for subsequent cardiovascular events and death.

RESULTS

One hundred and sixteen new cases of claudication were identified (incidence density 15.5 per 1000 person-years). Of those with claudication at baseline, 28.8% and still had pain after 5 years, 8.2% underwent vascular surgery or amputation, and 1.4% developed leg ulceration. Claudicants had a significantly increased risk of developing angina compared with normals (RR: 2.31, 95% CI: 1.04-5.10), and asymptomatic subjects had a slightly increased risk of myocardial infarction and stroke. Deaths from cardiovascular disease were more likely in both claudicants (RR: 2.67, 95% CI: 1.34-5.29) and subjects with major (RR: 2.08, 95% CI: 1.13-3.83) or minor asymptomatic disease (RR: 1.74, 95% CI: 1.09-2.76). Subjects with major asymptomatic disease also had an increased risk of non-cardiovascular death (RR: 2.19, 95% CI: 1.33-3.59), and therefore had the highest overall risk of death (RR: 2.44, 95% CI: 1.59-3.74).

CONCLUSIONS

Subjects with asymptomatic peripheral arterial disease appear to have the same increased risk of cardiovascular events and death found in claudicants.

Review of the nutrition policy of the Arnhem Land Progress Association

The process of implementation and the effect of the nutrition policy of the Arnhem Land Progress Association (ALPA) were reviewed three years after implementation of the policy in five remote Aboriginal community retail stores in May 1990. In 1993, compliance with the policy varied among stores. Recommended foods were available regularly in most communities; however, promotional and educational components of the policy were not widely implemented. Dietary improvements were evident in those communities where stores most complied with the policy. Some aspects of the ALPA nutrition policy require modification, and renewed commitment to the policy is likely to improve further the diet in the Aboriginal communities involved. The ALPA nutrition policy is a potential model for the development of other local food and nutrition policies in remote Aboriginal communities.

Haemostatic factors, atherosclerosis and risk of abdominal aortic aneurysm

Abdominal aortic aneurysms have traditionally been thought to be a consequence of severe atherosclerosis of the arterial wall. To date, the role of haemostatic factors in aneurysmal disease has not been extensively researched. The aim of this study was to see if such factors were independently related to the occurrence of aortic aneurysm. Furthermore, were the associations maintained after taking into account the presence of underlying atherosclerotic disease? Using data from the Edinburgh Artery Study, a nested case-control design was used involving 40 cases of aortic aneurysm, each being matched to five controls by sex and within a 5-year age band. After adjustment for age and sex, both fibrinogen (P < or = 0.01) and fibrin D-dimer (P < or = 0.001) were each associated with a significant increased risk of aneurysm. Further adjustment for packyears, history of cardiovascular disease and the ankle brachial pressure index resulted in odds ratios of 1.51 (95% CI 1.05 to 2.16, P < or = 0.05) for fibrinogen and 3.75 (95% CI 1.80 to 7.82, P < or = 0.001) for fibrin D-dimer. These associations probably arise as a consequence of fibrin deposition and turnover within the aneurysmal sac, although further prospective studies are needed before thrombotic factors can be used in the identification of a group who are at high risk of developing an abdominal aortic aneurysm.

Epidemiological comparison of injuries in school and senior club rugby

OBJECTIVE

To determine the frequency, nature, circumstances, and outcome of schoolboy rugby injuries and to compare these injuries with those occurring in senior rugby clubs.

METHODS

The study was a prospective cohort study, conducted on 1705 (98%) of 1736 eligible players from nine Edinburgh schools and 1169 (96%) of 1216 eligible players from all 26 senior Scottish Rugby Union clubs (South District) who provided personal details before the 1993-1994 rugby season. Adult linkpersons were appointed to notify the circumstances of all injury episodes occurring in matches or in rugby related training.

RESULTS

154 school players (9%) experienced 210 separate injuries in 186 injury episodes, 80% of which arose in matches. The prevalence rate of schoolboy match injuries was 86.8 (95% confidence interval 73.4 to 100.2) per 1000 player-seasons. Senior club match injury prevalence was much higher at 367.0 (339.4 to 394.6) per 1000 player-seasons. Club players had a higher rate of match injury than school-boys for all injury types. One third of schoolboy match injury episodes occurred in September and the majority of match injury episodes were associated with tackling (40%) or with being tackled (24%). Nine per cent of schoolboy match injury episodes were classified as severe, compared to 13% for clubs. Sixteen per cent (n = 23) of all schoolboy match injury episodes resulted in missed school attendance compared with 27% (n = 117) of all senior club match injury episodes which involved loss of employment or education.

CONCLUSIONS

Schoolboy rugby is much safer than senior club rugby and the outcome of injuries that do occur is less disruptive. The relatively high rate of match injury in September migh be reduced by a more intensive period of preseason training.

Randomised controlled trial of percutaneous transluminal angioplasty for intermittent claudication

OBJECTIVES

To determine differences between PTA and conventional medical treatment in treadmill distance until onset of claudication, treadmill maximum walking distance, patient reported maximum walking distance, ankle brachial pressure index (ABPI), quality of life (Nottingham Health Profile, NHP) and Duplex measured extent of occlusive disease.

DESIGN

Randomised controlled clinical trial.

METHODS

Six hundred claudicants were screened. Fifty-one men and 11 women with intermittent claudication due to short femoral stenoses or occlusions (n = 47) and iliac stenoses (n = 15) were randomised to either PTA plus medical treatment (PTA group, n = 30) or to medical treatment alone (control group, n = 32). Medical treatment consisted of daily low dose aspirin and advice on smoking and exercise.

RESULTS

At 6 month follow up: In the PTA group more patients reported no claudication (p < or = 0.05) and were asymptomatic on the treadmill (p < or = 0.01) compared to the control group. The ABPI was significantly higher in the PTA group. More of the PTA group reported lower NHP pain scores (p < or = 0.05). In the control group there were more occluded arteries (p < or = 0.001), and the stenosis velocity ratio of patient arteries was significantly higher (p < or = 0.001).

CONCLUSIONS

Only 10% of claudicants had discrete lesions suitable for PTA. Treatment of these patients with PTA produces a greater short-term improvement in walking and quality of life than medical treatment alone and is associated with less progression of disease.

Poststroke rehabilitation in older Americans. The Medicare experience

OBJECTIVES

This study examines the poststroke rehabilitation experience for a 20% sample of Medicare patients age 65 years and older admitted to an acute-care hospital with a stroke diagnosis during the 6-month interval, January 1, 1991 to June 30, 1991. Their Medicare claims data are used for two purposes: to identify current poststroke rehabilitation practice in the US population age 65 years and older, and to evaluate the importance of practice variation within this population.

METHODS

Regarding the first objective, the authors develop estimates for many poststroke rehabilitation use and cost parameters that formerly were unmeasured. With respect to the second objective, the authors construct and compare average service use rates across all stroke patients in a census division and across all stroke patients residing in the 30 largest metropolitan statistical areas.

RESULTS

The authors' Medicare claims analysis indicates that 73% of stroke survivors received either postacute institutional or ambulatory rehabilitation care during the first 6 months poststroke. The published stroke literature, on the other hand, focuses on the minority of stroke survivors, 16.5% in the Medicare data, who were admitted to an inpatient rehabilitation hospital. Regarding the second study objective, the Medicare analysis provides graphic evidence that poststroke rehabilitation practice varies substantially from one geographic area to another and that practice differences translate into large geographic-related differences in the cost of poststroke rehabilitation.

CONCLUSIONS

The authors believe the findings demonstrate a problem with inconsistent poststroke rehabilitation practice.

Inter-relationships of plasma fibrinogen, low-density lipoprotein cholesterol, cigarette smoking and the prevalence of cardiovascular disease

BACKGROUND

The magnitude of the cardiovascular risk associated with plasma fibrinogen concentration is influenced separately by cigarette smoking and by low-density lipoprotein (LDL) cholesterol levels. The effects of combinations of these factors on risk and the extent to which inclusion of the plasma fibrinogen level further refines the risks associated with smoking and high LDL cholesterol levels are not known.

OBJECTIVE

To determine the inter-relationships among all of the three factors smoking, LDL cholesterol level and fibrinogen level with respect to the occurrence of cardiovascular disease.

METHODS

The study was part of the Edinburgh Artery Study, which was a cross-sectional random sample survey of 1592 men and women aged 55-74 years. The assessment of cardiovascular disease included recall of diagnosis by a doctor of angina or myocardial infarction, intermittent claudication determined by a questionnaire and measurement of ankle systolic blood pressure.

RESULTS

The odds ratio for disease in smokers in the top tertiles of plasma fibrinogen and LDL cholesterol levels was 7.7 (95% confidence interval 3.0-19.8; P < or = 0.001). Neither a multiplicative nor a synergistic effect of the three factors on the odds of disease was observed but the level of each contributed to the risk. For example, in current smokers in the bottom tertile of LDL cholesterol level, the odds of disease were 6.1 (95% confidence interval 2.2-17.0; P < or = 0.001) in the top tertile, 2.9 (95% confidence interval 1.0-8.6; P < or = 0.05) in the middle tertile and 1.6 (95% confidence interval 0.5-4.8; P > 0.05) in the bottom tertile of plasma fibrinogen level. Subjects in the bottom tertile of plasma fibrinogen level did not have significantly elevated (P < 0.05) risks irrespective of LDL cholesterol levels and smoking status.

CONCLUSION

The incorporation of plasma fibrinogen level permitted more precise delineation of the odds of disease within categories of smoking and LDL cholesterol concentration. These relationships need to be investigated further in prospective studies.

Perceptions of urinary symptoms and health-care-seeking behaviour amongst men aged 40-79 years

BACKGROUND

Little is known about why men fail to seek medical help for urological symptoms.

AIM

This study was designed to document men's perceptions of urinary symptoms and to increase understanding of health-care-seeking behaviour.

METHOD

A stratified random sample of men aged 40-79 years was drawn from the age-sex register of a health centre in Central Scotland. Two hundred men were interviewed using semi-structured qualitative techniques and asked to complete a symptom questionnaire. The response rate was 65%.

RESULTS

Urinary symptoms reported to be most bothersome were dribbling, hesitancy and straining. All but the youngest age group (40-49 years) associated developing urinary symptoms with ageing. This was considered to be a reason not to consult a doctor. Most symptoms were not thought to be serious. Pain, haematuria and acute retention gave cause for concern, and were perceived as reasons for seeking medical help. Although urinary symptoms interfered with selected activities in daily life, this was not a worry to the men and was not seen to be a sufficient reason alone to consult their general practitioner.

CONCLUSION

The insidious development of urinary problems over time reinforces the belief that it is part of getting older and accounts for the accommodation of symptoms within men's everyday living experiences. Bothersomeness associated with urinary symptoms was not synonymous with worry or problems. Doctors must be prepared to initiate discussion about urinary function in order to assess the impact of symptoms on an individual's daily life.

Association between milk protein genetic variants and genetic values of Canadian Holstein bulls for milk yield traits

The kappa-casein, beta-casein, and beta-lactoglobulin genotypes of 566 bulls were identified by polymerase chain reaction. The associations of these milk protein types with the daughter yield deviations of the 566 bulls for milk, fat, and protein were examined with a mixed model analysis using an animal model. The results suggest that kappa-casein and beta-casein loci had no significant effects on ETA of the bulls for milk, fat, and protein. The effect of beta-lactoglobulin on ETA of protein approached significance. Results suggest that increasing the frequency of the A variant of beta-lactoglobulin in young bulls entering progeny testing improves ETA for protein of the bulls, but the expected improvement is limited.

A multiple-pathway model for the diffusion of drugs in skin

A mathematical model for the diffusion of drugs in skin is presented. The penetration of the drug by both transcellular and intercellular pathways, as well as its interchange between these pathways, is considered. A pharmacologically motivated asymptotic limit is identified and analysed to obtain, in particular, an analytical expression for the flux of drug to the blood at steady state. Relevant model data is discussed, and some numerical results are also presented.

Metformin in noninsulin-dependent diabetes mellitus

Metformin is an oral antihyperglycemic agent that is approved by the Food and Drug Administration for the treatment of noninsulin-dependent diabetes mellitus. It differs from the sulfonylureas in that it is does not enhance insulin secretion and normally does not produce hypoglycemia. Metformin acts to decrease preprandial and postprandial blood glucose concentrations by increasing skeletal muscle uptake of glucose, decreasing gluconeogenesis, and decreasing absorption of glucose. The addition of metformin to maximum dosages of a sulfonylurea may synergistically improve glucose control. The drug may offer other potential benefits, such as weight loss or minimal weight gain, improved blood flow in patients with peripheral vascular disease, reduction of tissue plasminogen activator inhibitor, and improved lipid profiles. It is relatively safe if taken appropriately. Its most common side effects are gastrointestinal (nausea, diarrhea, anorexia), metallic taste, and vitamin B12 malabsorption. Lactic acidosis may also occur, but it is rare if metformin is avoided in patients with contraindications to its use. With careful monitoring, the agent may be considered for the initial treatment of obese patients who fail dietary measures, and those whose disease is refractory to maximum dosages of sulfonylureas or who do not tolerate them.

Variation in cardiovascular risk factors by angiographic site of lower limb atherosclerosis

OBJECTIVE

To determine differences in the levels of the cardiovascular risk factors, cigarette smoking, serum lipids and blood pressure, between three groups of patients with different sites of lower limb atherosclerosis.

DESIGN

Cross-sectional survey of a consecutive series of patients with symptoms of either intermittent claudication or rest pain.

METHODS AND MATERIALS

One hundred and ninety-two men and women who had undergone angiography were classified using the Bollinger scoring system into groups with predominantly aortoiliac, femoropopliteal or dual-site disease. History of cigarette smoking, serum cotinine, serum thiocyanate, total cholesterol and HDL cholesterol were estimated. Systolic and diastolic pressures were measured and the ankle brachial pressure index (ABPI) was calculated.

RESULTS

Eighty-five patients were classified as having femoropopliteal disease, 34 aortoiliac disease and 73 dual-site disease. After adjusting for age, sex and severity of disease, aortoiliac patients were significantly younger (p </- 0.001), more likely to be female and current smokers, and had the highest levels of diastolic blood pressure. Life time cigarette consumption (pack-years) and total cholesterol concentrations were highest in femoropopliteal disease. Patients with dual-site disease were more likely to have had a myocardial infarction and angina pectoris (p </- 0.05). Systolic blood pressure was also highest in this group.

CONCLUSION

different levels of cardiovascular risk factors may predispose individuals to atherosclerosis at different sites in the lower limb. Large population studies would be required to delineate the risks more precisely.