bluuebunny/crossref_metadata_2025 huggingface dataset:
Videophotometric capillaroscopy for evaluating drug effects on skin microcirculation—a double‐blind study with nifedipine
Authors: Östergren Jan , Fagrell Bengt
Published: April 2008

Summary. By videophotometric capillaroscopy, blood flow dynamics in the nutritional skin capillaries of man can be quantified. In this double‐blind crossover study the acute effect of nifedipine on finger nailfold capillary blood cell velocity (CBV) was investigated in 10 healthy subjects. At the moment of administration of 10 mg nifedipine or placebo sublingually, a transitory but significant increase in heart rate and reduction of digital pulse amplitude (DAPA) were seen. Subsequent measurements of DAPA and heart rate were not significantly different from the baseline ones. CBV however increased after 10 min to a maximum of 49% above baseline values (P<O‐OS) after nifedipine but was unaffected by placebo. The reactive hyperaemia response in the capillaries were unaffected by both placebo and nifedipine. The decrease in DAPA and increase in heart rate upon administration of the drug or placebo are compatible with an increase in sympathetic activity. The subsequent increase in CBV indicates that nifedipine diminishes precapillary vascular tone. However, the drug seems to affect arterio‐venous shunt flow to a lesser extent since DAPA did not increase significantly. Videophotometric capillaroscopy is a suitable method for studying the effects of pharmacological compounds on nutritional circulation in human skin.
51Cr‐EDTA clearance determined by one plasma sample in children
Authors: Groth Steffen , Aasted Michael
Published: April 2008

Summary. 51Cr‐EDTA clearance was determined in 50 children from the activity in one plasma sample by means of two methods. The calculation of 51Cr‐EDTA clearance by method I (ClI) was based on a transformation of the biexponential time‐activity curve into a monoexponential with identical area below the time‐activity curve. The calculation of 51Cr‐EDTA clearance by method II (ClII) was based on a close relation between 51Cr‐EDTA clearance and the reciprocal apparent volume of distribution normalized with respect to body surface area. It was demonstrated that the two methods were closely related. To test the accuracy of the two methods, the results of ClI and CIII, were compared to 51‐EDTA clearance calculated by means of a standard, multiple plasma sample method (ClSM). The correlations between ClSM and ClI, and between and ClII were almost identical (r= 0·993 and r = 0·992). The accuracy of 51Cr‐EDTA clearance calculated as ClI and ClII did not differ significantly from each other.
Plasma 3‐methyIbutanal in man and its relationship to hepatic encephalopathy
Authors: Marshall Alex W , DeSouza Marlette , Morgan Marsha Y
Published: April 2008

Summary. . 3‐Methylbutanal is a volatile aldehyde which in the rat is derived, at least in part, from colonic bacterial breakdown of leucine. It has been proposed as a toxin of importance in the pathogenesis of hepatic encephalopathy in man. A rapid, reliable and highly reproducible method for estimating 3‐methylbutanal in plasma is described using a gas‐chromatograph with a head space‐sampler. The mean plasma 3‐methylbutanal concentration in non‐fasting patients with hepatic encephalopathy, 0–244 umol/litre (range 0–1‐30) was not significantly different from the mean value in controls, 0–116 umol/litre (0‐0‐349). Oral leucine feeding resulted in significant increases in plasma 3‐methylbutanal concentrations in both control subjects and patients with cirrhosis. Peak leucine and 3‐methylbutanal values occurred at approximately the same time and usually within 120 min of leucine ingestion. Pre‐treatment with neomycin had no effect on the results of leucine feeding. No changes occurred in the clinical condition or psychometric performance of patients with cirrhosis fed leucine despite increases in plasma 3‐methylbutanal of up to 700% over basal values. In man plasma 3‐methylbutanal, at least in part, derives from ingested leucine independently of the action of colonic bacteria. The role of this compound in the pathogenesis of hepatic encephalopathy in man needs further exploration.
Cardiovascular responses to circulating catecholamines in normal pregnancy and in pregnancy‐induced hypertension
Authors: Nisell Henry , Hjemdahl Paul , Linde Birgitta
Published: April 2008

Summary. Patients with pregnancy‐induced hypertension (PIH) and healthy pregnant and non‐pregnant women were compared with regard to cardiovascular responses to i.v. infusions of noradrenaline (NA) and adrenaline (ADR). This resulted in physiologically relevant concentrations in arterial plasma (maximally 10 nmol/litre for NA and 6 nmol/litre for ADR). Non‐pregnant women responded to NA with concentration‐dependent increases in blood‐pressure, which were caused by peripheral vasoconstriction, as systemic vascular resistance (SVR) was increased by 21%. Cardiac output was reduced by 6%. ADR caused concentration‐dependent decreases in SVR (to values 36% below basal) and calf vascular resistance (CVR), as well as increases in cardiac output. Healthy pregnant women responded to NA with similar increases in blood‐pressure, but this was due to stroke volume‐dependent increases in cardiac output (11%) and not due to vasoconstriction. ADR‐induced vasodilatation was attenuated in this group. Cardiac responses to ADR were unaffected by pregnancy. PIH patients demonstrated an enhanced systolic blood‐pressure response to NA (19% increase vs 7–8% in the other groups) due to the combined effects of vasoconstriction (11% increase in SVR) and an essentially unchanged cardiac output. ADR‐induced decreases in CVR and diastolic blood‐pressure were similar to those found in the non‐pregnant group. Increases in heart rate were less pronounced, but cardiac output increased as normal.

These results indicate that normal pregnancy is associated with attenuated vascular responses to circulating catecholamines. PIH patients do not seem to have undergone this normal adaptation of the vascular system to pregnancy.
Heat and water respiratory exchanges: comparison between mouth and nose breathing in humans
Authors: VaréGne Pierre , Ferrus Lydia , Manier GéArard , Gire Jany
Published: April 2008

Summary. The temperatures(T1 TE) of inspired and expired gas and the mass of expired water (MEH2O) have been measured in four subjects at rest during mouth and nose breathing of dry air at room temperature. T1 and TE were measured by copper‐constantan thermocouples, MEH2O by freezing and ventilatory parameters by total body plethysmography. During mouth breathing, temperatures are significantly higher (T1= 28·1°C, TE= 31·5°C) and the amount of expired water larger (MEH2O = 27·8 mg dm‐3 BTPS) than during nose breathing (T1, = 24·8°C; TE= 29·6°C; MEH2O =26·6 mg dm‐3 BTPS). From these experimental data the appropriate computations show clearly that in humans, while either nose or mouth breathing, (1) the expired air is not water saturated; (2) the latent heat exchanges represent the larger part of the respiratory heat exchanges; (3) the counter current expiratory heat recovery is imperfect; (4) in terms of heat and water respiratory exchanges, no large difference exists between the oral and nasal routes. This last point is confirmed by the calculation of a difference less than 10% in the total respiratory heat losses between mouth and nose breathing.
Spectral analysis with digital presentation of C‐W Doppler signals in the evaluation of carotid stenosis
Authors: Jungquist G. , Olivecrona H. , Kendrup I. , Bornmyr S. , Norrving B. , Takolander R. , Lindell S. E.
Published: April 2008

Summary. Using a continuous‐wave ultrasound Doppler system with spectral analysis (FFT) and digital processing and presentation, the Doppler shift characteristics of the carotid arteries were studied in 40 healthy subjects (20 men and 20 women; average age 69 years). The reference values, thus obtained, were applied to the analysis of sonograms from 46 carotid arteries, which were also studied angiographically. Stenoses which reduced the diameter of the internal carotid artery by more than 30% could be identified with a sensitivity of 97% and a specificity of 100%. The results extend previous experience that spectral analysis improves the usefulness of the ultrasound Doppler system in the evaluation of carotid artery disease. The addition of digital processing and presentation of the Doppler shift characteristics increases the diagnostic precision and provides a permanent record.

The importance of well‐trained sonographers and adequate reference values is emphasized.
Skeletal muscle characteristics in children 9–15 years old: force, relaxation rate and contraction time
Authors: Bäckman E. , Henriksson K. G.
Published: April 2008

Summary. Relaxation rate (RR), half contraction time to tetanus (CTT1/2) and force‐frequency curves were investigated in 77 children, aged 9–15 years, using supramaximal stimulation of the ulnar nerve and recording from the adductor pollicis muscle. No sex differences were found in these variables. The RR was independent of age and similar to that in adults. The CTT1/2 was least at the age of 15. The only age‐dependent parameter in the force‐frequency curves was the relative force developed at a stimulus frequency of 10 Hz, which increased with increasing age. A fatiguability test was performed in 25 children. Reference values for the different parameters are given.
Thermography and laser‐Doppler flowmetry for monitoring changes in finger skin blood flow upon cigarette smoking
Authors: Bornmyr S. , Svensson H.
Published: April 2008

Summary. Haemodynamic changes after smoking two 1·1 mg nicotine cigarettes were monitored in 24 smokers on two different occasions. Smoking caused an increase in heart rate and arterial blood pressure, whereas finger temperature as measured by thermography and finger skin blood flow as measured by laser‐Doppler flowmetry (LDF) decreased. Lowest values were seen within 15 min by LDF, and after 30 min by thermography. Changes in the two methods correlated closely, however, when maximum responses during a 45‐min period after smoking were compared. The wider distribution of LDF values would seem to be due to the small measuring volume which is susceptible to differences in vascular anatomy and reactivity. In both methods, responses showed a high degree of reproducibility.
Endothelial mediated enhancement of noradrenaline induced vasoconstriction in normal and varicose veins
Authors: Thulesius O. , Said S. , Shuhaiber H. , Neglen P. , Gjores J. E.
Published: April 2008

Summary. The role of the endothelium to influence smooth muscle contraction in normal and varicose veins was investigated in vitro using saphenous vein preparations obtained at vascular surgery. Paired control and endothelium‐denuded rings were tested simultaneously and contracted with noradrenaline (10‐9‐10‐4 M). Identical experiments were also performed on sheep femoral veins and arteries. Noradrenaline induced maximal tension was 30% lower in varicose compared to normal veins. In normal veins removal of endothelium significantly reduced the maximal response to noradrenaline by 40% whereas in varicose veins no significant reduction could be seen. In the sheep femoral vein removal of the endothelium also resulted in decrease of noradrenaline‐induced contraction. It can be concluded that in the human saphenous vein the endothelium has a contraction facilitating effect in response to stimulation with noradrenaline. In varicose veins the endothelial‐mediated enhancement of noradrenaline‐induced vasoconstriction is reduced probably because of endothelial damage. This observation may be of importance in the pathogenesis of varicose veins.
A comparison of Doppler ankle pressures and skin perfusion pressure in subjects with and without diabetes
Authors: Quigley F. G. , Faris I. B. , Duncan H. J.
Published: April 2008

Summary. Doppler ankle pressure measurements may be misleading in some patients because medial calcification has made the arteries of the leg incompressible. This problem is especially common in diabetics. Medial calcification that is not severe enough to make an artery clinically incompressible may cause an increased stiffness of the arterial wall that will limit the accuracy of Doppler ankle pressure measurements. A comparison of skin perfusion pressure, using an isotope technique, and Doppler ankle pressures was made in 226 subjects, diabetic and non‐diabetic. Patients with incompressible arteries were excluded from the study. The slopes of the regression lines relating skin perfusion pressure to Doppler ankle pressure in diabetic and non‐diabetic subjects were significantly different (P= 0.03). This result was consistent with the hypothesis that diabetic subjects have arteries that are less compressible than normal arteries and may make Doppler ankle pressure measurements in diabetic subjects misleading over th whole range of pressures recorded.
Relationships between skin temperature and perfusion in the arm and leg
Authors: Stoner H. B. , Barker P. , Riding G. S. G. , Hazlehurst D. E. , Taylor L. , Marcuson R. W.
Published: April 2008

Summary. Relationships between skin temperature (Tsk) and perfusion have been studied to provide a basis for the use of Tsk in the non‐invasive assessment of limb circulation in peripheral vascular disease.

Raising the ambient temperature (Ta) from 20 to 30°C increased the perfusion of the glabrous skin of the hands and feet without changing that of the skin of the forearm or calf. On a fractional basis the response in the hand and foot was the same. Tsk was higher in the arms than the legs and in the proximal than distal parts of the limbs. A fall in Tsk was often seen when Ta rose from 20 to 25°C and was attributed to counter‐current cooling. Subsequently Tsk rose even in regions where there was no increase in skin perfusion. Tsk can only be related to its perfusion in the fingers, palm and toes. Forearm Tsk was related to the perfusion of the digits. This relationship implies a link with the arterial inflow to the limb which determines the size of its thermal core. Heat conduction from the core seemed important for the skin of areas like the forearm and calf where the constant, low perfusion limited the amount of heat which could be transported to it directly by the blood.

The importance of conduction was supported by studies, at Ta 20°C, on subjects during calf muscle exercise and on patients with arterio‐venous fistulae. Here an increase in the arterial inflow to the limb was associated with a rise in Tsk of the forearm/calf unrelated to the perfusion of its skin.
Cardiac contractility, central haemodynamics and blood pressure regulation during semistarvation
Authors: Stokholm K. H. , Breum L. , Astrup A.
Published: April 2008

Eight obese patients were studied before and after 2 weeks of treatment by a very‐low‐calorie diet (VLCD). Cardiac output and central blood volume (pulmonary blood volume and left atrial volume) were determined by indicator dilution (125I‐albumin) and radionuclide angiocardiography (first pass and equilibrium technique by [99Tcm]red blood cells). Cardiac output decreased concomitantly with the reduction in oxygen uptake as the calculated systemic arteriovenous difference of oxygen was unaltered. There were no significant decreases in left ventricular contractility indices, i.e. the ejection fraction, the peak ejection rate and changes in end‐systolic volume. Also the diastolic function evaluated by the peak filling rate remained normal. Furthermore, no sign of backward failure could be demonstrated since the central blood volume was not significantly increased. Both systolic and diastolic blood pressure (BP) declined. The fall in BP was caused by the reduction in cardiac output as the total peripheral resistance was unchanged. Finally, the decline in total blood volume was not significant. These findings together with a reduction in heart rate indicated that a reduced sympathetic tone via increased capacitance of the venous bed was the main operator of a reduced venous return. Thus, the haemodynamic alterations in obese patients during short‐term semistarvation may be caused by the fall in oxygen uptake and produced mainly by changes in the sympathetic tone.
Blood volume distribution during head‐up tilt induced central hypovolaemia in man
Authors: MatZen S. , Perko G. , Groth S. , Friedman D. B. , Secher N. H.
Published: April 2008

Summary. We evaluated regional electrical impedance (Z°) at 2.5 and 100 kHz to separate intra‐ and extracellular fluid changes and correlated Z° over the thorax (TI) to relative changes in the central blood volume (CBV) induced by head‐up tilt. In nine experiments head‐up tilt resulted in normotensive central hypovolaemia associated with a 3·7 & 0·4 Ohm (mean f SE) increase in TI100 kHz after 60 min. In 24 experiments presyncopal symptoms were induced after 43±2 min, when TI100kHz had increased 4·2 ± 0·2 Ohm. Head‐up tilt instantly decreased the activity of technetium labelled erythrocytes (99Tcm) over the thorax by 24 ± 2%, and increased 99Tcm over the thigh by 68±10% (P< 0·01, n = 8) with no further changes during the sustained tilt. Haematocrite increased during head‐up tilt from 43·1 ± 0·3 to 47·9 ± 0·6% (P<0·01, n= 8). Accordingly, the increase in TI (6·3 ± 0·6 vs. 4·5 0·4 Ohm, n= 6) and the decrease in Z° through one leg (7·2 ± 1·2 vs. 2·8 ± 0·5 Ohm, n= 6) at 2·5 kHz was more pronounced than at 100 kHz. Also the changes in TI were correlated to CBV as calculated from 99Tcm and haematocrite (r = 0.90, P < 0·01). The results suggest that:

(1) Hypovolaemic shock is associated with a faster increase of TI than normotensive head‐up tilt.

(2) Head‐up tilt is characterized by an initial decrease in CBV followed by a further decrease in plasma volume, which eventually leads to hypovolaemic shock.

(3) Blood volume changes during head‐up tilt are reflected in regional Z°.
Effect of acute acidosis and alkalosis on leucine kinetics in man
Authors: Straumann E. , Keller U. , Kury D. , Bloesch D. , Thélin A. , Arnaud M. J. , Stauffacher W.
Published: April 2008

Summary. The effects of acute pH changes on whole body leucine kinetics (1‐13C‐leucine infusion technique) were determined in normal subjects. Plasma insulin, glucagon, and growth hormone concentrations were kept constant by somatostatin and replacement infusions of the three hormones.

When acidosis was produced by ingestion of NH4CI (4 mmol kg‐1 p. os; n = 8) arterialized pH decreased within 3 h from 7.39±0.01 to 7.31 ±0.01 (P<0.001) and leucine plasma appearance increased by 0.13 ±0.04 μmol kg‐1 min‐1 (P<0.02); in contrast, when alkalosis was produced by intravenous infusion of 4 mmol kg‐1 NaHCO3 (n= 1, pH 7.47 ±0.01), leucine plasma appearance decreased by ‐0.09 ± 0.04 (xmol kg‐1 min‐1 (P<0.01 vs. acidosis). Whole body leucine flux also increased during acidosis compared to alkalosis (P<0.05), suggesting an increase in whole body protein breakdown during acidosis. Apparent leucine oxidation increased during acidosis compared to alkalosis (P=0.05). Net forearm leucine exchange remained unaffected by acute pH changes.

Plasma FFA concentrations decreased during acidosis by ‐107 ±67 μmol l‐1 (P<0.05) and plasma glucose increased by 1.90±0.25 mmol l‐1 (P<0.02); in contrast, alkalosis resulted in an increase in plasma FFA by 83 ± 40 (μmol 1‐1 (P<0.02; P<0.01 vs. acidosis), suggesting an increase in lipolysis; plasma glucose decreased compared to acidosis (P<0.01).

The data demonstrate that acute metabolic acidosis and alkalosis, as they occur in clinical conditions, influence protein breakdown, and in the opposite direction, lipolysis.
Haemodynamic and neurohumoral effects of cold pressor test in severe heart failure
Authors: Westheim A. , Os I. , Thaulow E. , Kjeldsen S. E. , Eritsland J. , Eide I. K.
Published: April 2008

Summary.The effect of a cold pressor test (CPT) on haemodynamics in relation to general and regional sympathetic activity and arginin vasopressin (AVP), was studied in eleven patients with severe congestive heart failure (CHF). Compared to an age‐matched control group (C), resting arterial plasma noradrenaline (NA) (419 ±77 vs. 182 ±15 pg ml‐1), and adrenaline (A) (142 ±28 vs 54 ±10 pg ml‐1) were higher (P<0.05) in CHF. AVP showed no significant difference (14±4 vs. 9±4 pg ml‐1). During CPT systolic and diastolic blood pressure and systemic vascular resistance increased (P<0.01), as did NA (δ 114±39 pg ml‐1, P<0.01), A (δ 33 ± 10 pg ml, P<0.01) and heart rate (δ 10 beats min‐1, P<0.01). The myocardial v‐a difference of NA decreased (P<0.05), but was unchanged across the renal vascular bed during CPT. The a‐v difference of NA in the hepatic vascular bed, and fractional extraction of A in the coronary sinus, renal and hepatic vascular beds remained unchanged during CPT. AVP did not change significantly and no change in cardiac index or left ventricular filling pressure was observed during CPT.

These data suggest that despite an increased activation of the sympathetic nervous system at rest, a further increase in blood pressure and catecholamines took place during CPT. Thus, the effect of a CPT which activates the central sympathetic system seems not to be altered in patients with severe CHF.
Oesophageal dysfunction in familial amyloidosis with polyneuropathy
Authors: Bjerle P. , Ek B. , Linderholm H. , Steen L.
Published: April 2008

Summary. Sixteen patients with familial amyloidosis and polyneuropathy (FAP) and 14 healthy subjects underwent oesophageal manometry. Six of the patients had a severe oesophageal dysmotility with almost completely abolished propulsive pressure waves on swallowing in the lower 2/3 of the oesophagus. Ten patients had moderate dysfunction with reduced propulsive pressure wave amplitudes. Neostigmine increased the pressure wave amplitudes in healthy subjects but less so in the FAP patients. Scopolamine (Scopyl)‐terbutaline (Bricanyl) almost abolished the propulsive pressure waves in healthy subjects and all patients in the lower 2/3 of the oesophagus. Oesophageal distensibility, tested by inflating a rubber balloon in the oesophagus, was similar in FAP patients and healthy subjects. Thus, it is unlikely that amyloid deposits in the mucosal wall increased the oesophageal stiffness. An autonomic, predominantly vagal, denervation probably explains the disturbed function.
Electrical impedance measured changes in thoracic fluid content during thoracentesis
Authors: Petersen J. R. , Jensen B. V. , Drabaek H. , Viskum K. , Mehlsen J.
Published: April 2008

Summary. In patients (seven females and 11 males) with pleural effusion due to pulmonary (n= 13) or cardiac disease (n= 5) the change in baseline transthoracic impedance (Z0) was measured by electrical impedance (BoMed's NCCOM‐3, 70 kHz) during thoracentesis. Data were obtained before and after withdrawal of each 500 ml, and at the end of the thoracentesis. We found a close linear correlation (r= 0–97) between changes in Z0 and the volume of aspirated pleural effusion (y= 0–415 x+0–093). The variability of the estimated thoracic fluid volumes was analysed with a plot of the residuals from the regression line, and we found that changes in thoracic fluid volume estimated by impedance technique would be within ± 302 ml (=2 SD). However, the absolute value of Z0 before thoracentesis could not differentiate the group of patients with pleural effusion from normal subjects (n= 28).
Effects of mental state on heart rate and blood pressure variability in men and women
Authors: Madden K. , Savard G. K.
Published: April 2008

Summary. The effect of different mental states on autonomic modulation of the cardiovascular system was assessed in healthy, normotensive men (n=18) and women (n=12). Heart rate variability (HRV), systolic blood pressure variability (BPV) and arterial baroreflex function were assessed during 4 tests at rest ((10 min+5 min recovery)×4):

Control (spontaneous breathing, (SB)

Mental distraction (SB+word puzzle)

Conscious control of breathing (paced at SB rate) and

Mental stress (SB+computer quiz).

There were no significant gender differences in the responses to the interventions in terms of arterial (spontaneous) baroreflex (SPBX) control of HR, and indices of time and frequency domains of HRV and BPV, with the exception of the sympathetic indicator of HRV (low frequency power/total power; P<0.01) which was lower in women during control and mental stress tests. Conscious control of breathing at SB did not alter HRV, BPV or SPBX in either men or women. Mental distraction and mental stress led to decreases in indices of time and frequency domains of HRV and BPV in all subjects, as well as increases in HR during distraction and in systolic BP during stress. These findings suggest that in studies of cardiovascular control:

Paced breathing at SB can be used for individuals with irregular breathing patterns

The extent of mental stress achieved is intervention‐specific and for the most part, independent of gender and

Resting assessment of HRV, BPV and SPBX can be made by having subjects sit quietly without interventions in a controlled laboratory setting.
Exercise‐induced changes in neuropeptide Y, noradrenaline and endothelin‐1 levels in young people with type I diabetes
Authors: Ahlborg G. , Lundbergt J. M.
Published: April 2008

SUMMARY. In search of early signs of autonomic and vascular dysfunction in diabetic subjects, six young men with type I diabetes and six healthy subjects were investigated regarding arterial levels of noradrenaline (NA), neuropeptide Y‐ (NPY) and endothelin‐1‐ (ET‐1) like immunoreactivity (Li) during and after 1 h of exercise at 70% of peak oxygen uptake. Basal NA, NPY‐Li and ET‐l‐Li levels did not differ between groups. NA and NPY‐Li rose during exercise in diabetic subjects to only 60% of the control values (P < 0–05, interaction groupxtime P < 0–001). Disappearance rates for NA and NPY‐Li did not differ between groups. Plasma ET‐l‐Li did not differ between groups during exercise. Values returned to basal levels within 5 min in the diabetic but not in the control group.
Rotating maps and readers: praxiological aspects of alignment and orientation
Authors: Laurier Eric , Brown Barry
Published: April 2008

A longstanding topic in our notions of what geographic knowledge could be is the mental map, or, in its most recent form, mental spatial representations. In this paper we draw upon ethnomethodological critiques of cognition, and mind more generally, to re‐specify navigation, orientation and alignment in terms of human practices of navigating, orienting and aligning in particular settings. Our ambition in the paper is less to dismantle notions of cognition still present in geographers’ studies of map use; instead we offer the beginnings of a way of analysing ordinary practices of wayfinding that treats matters of reasoning as publicly available in gestures and conversation rather than indirectly accessible inner processes of mental map consultation. To do so we describe what occurs during two video fragments involving consultation of maps in commonplace situations. The first is a group of tourists on foot trying to find an old building in Edinburgh and the second daytrippers travelling out for a day in the countryside locating some recommended places to visit in a road atlas.
Multimethod Evaluation of Health Policy Change: An Application to Medicaid Managed Care in a Rural State
Authors: Waitzkin Howard , Schillaci Michael , Willging Cathleen E.
Published: April 2008

Objective. To answer questions about the impacts of Medicaid managed care (MMC) at the individual, organizational/community, and population levels of analysis.

Data Sources/Study Setting. Multimethod approach to study MMC in New Mexico, a rural state with challenging access barriers.

Study Design. Individual level: surveys to assess barriers to care, access, utilization, and satisfaction. Organizational/community level: ethnography to determine changes experienced by safety net institutions and local communities. Population level: analysis of secondary databases to examine trends in preventable adverse sentinel events.

Data Collection/Extraction Methods. Survey: multivariate statistical methods, including factor analysis and logistic regression. Ethnography: iterative coding and triangulation to assess documents, field observations, and in‐depth interviews. Secondary databases: plots of sentinel events over time.

Principal Findings. The survey component revealed no consistent changes after MMC, relatively favorable experiences for Medicaid patients, and persisting access barriers for the uninsured. In the ethnographic component, safety net institutions experienced increased workload and financial stress; mental health services declined sharply. Immunization rate, as an important sentinel event, deteriorated.

Conclusions. MMC exerted greater effects on safety net providers than on individuals and did not address problems of the uninsured. A multimethod approach can facilitate evaluation of change in health policy.
Effect of Eliminating Behavioral Health Benefits for Selected Medicaid Enrollees
Authors: McConnell K. John , Wallace Neal T. , Gallia Charles A. , Smith Jeanene A.
Published: April 2008

Objective. To determine the extent to which the elimination of behavioral health benefits for selected beneficiaries of Oregon's Medicaid program affected general medical expenditures among enrollees using outpatient mental health and substance abuse treatment services.

Data Source/Study Setting. Twelve months of claims before and 12 months following a 2003 policy change, which included the elimination of the behavioral health benefit for selected Oregon Medicaid enrollees.

Study Design. We use a difference‐in‐differences approach to estimate the change in general medical expenditures following the 2003 policy change. We compare two methodological approaches: regression with propensity score weighting; and one‐to‐one covariate matching.

Principal Findings. Enrollees who had accessed the substance abuse treatment benefit demonstrated substantial and statistically significant increases in expenditures. Individuals who accessed the outpatient mental health benefit demonstrated a decrease or no change in expenditures, depending on model specification.

Conclusions. Elimination of the substance abuse benefit led to increased medical expenditures, although this offset was still smaller than the total cost of the benefit. In contrast, individuals who accessed the outpatient mental health benefit did not exhibit a similar increase, although these individuals did not include a portion of the Medicaid population with severe mental illnesses.
Seed Market Privatisation and Farmers’ Access to Crop Technologies: The Case of Hybrid Pearl Millet Adoption in India
Authors: Matuschke Ira , Qaim Matin
Published: April 2008

In India, pearl millet is a typical subsistence crop. Nonetheless, use of hybrid seeds is widespread. The first pearl millet hybrids were introduced in 1965 by the public sector. Yet, starting in the late 1980s, market liberalisation led to an increasing role of private companies in seed development and distribution. Although several studies showed that proprietary pearl millet hybrids are more productive than public hybrids and open‐pollinated varieties, the impacts of privatisation on farmers’ technology access and overall innovation rates are not yet well understood. This paper analyses the dynamics of adoption using duration models and farm survey data collected in the state of Maharashtra. The results show that education, short distances to main information sources and good market infrastructure speeded up the adoption of pearl millet hybrids. Likewise, the increasing role of private seed companies had a positive and accelerating effect on technology diffusion in the small farm sector.
Hepatitis B Virus Infection and the Dialysis Patient
Authors: Fabrizi Fabrizio , Messa Piergiorgio , Martin Paul
Published: April 2008

Prevention of nosocomial transmission of hepatitis B virus (HBV) has been a signal achievement in the management of chronic kidney disease. The rate of serum hepatitis B surface antigen (HBsAg) seropositivity in patients on maintenance hemodialysis in the developed world is currently low (0–10%) but outbreaks of acute HBV infection continue to occur in this setting. The prevalence of HBV infection within dialysis units in developing countries appears higher (2–20%) based on relatively few reports. Although data are limited, HBV infection in dialysis population diminishes survival; HBV viral load in HBsAg‐positive dialysis patients is reportedly low and stable over time. Updated recommendations for the management of HBsAg chronic carriers on maintenance dialysis have been issued. No rigorously controlled treatment trials for treatment of hepatitis B with either interferon or lamivudine therapy in dialysis patients are currently available.
Determining Care Management Activities Associated with Mastery and Relationship Strain for Dementia Caregivers
Authors: Connor Karen I. , McNeese‐Smith Donna K. , Vickrey Barbara G. , Van Servellen Gwen M. , Chang Betty L. , Lee Martin L. , Vassar Stefanie D. , Chodosh Joshua
Published: April 2008

OBJECTIVES: To identify specific care management activities within a dementia care management intervention that are associated with 18‐month change in caregiver mastery and relationship strain.

DESIGN: Exploratory analysis, using secondary data (care management processes and caregiver outcomes) from the intervention arm of a clinic‐level randomized, controlled trial of a dementia care management quality improvement program.

SETTING: Nine primary care clinics in three managed care and fee‐for‐service southern California healthcare organizations.

PARTICIPANTS: Two hundred thirty‐eight pairs: individuals with dementia and their informal, nonprofessional caregivers.

MEASUREMENTS: Care management activity types extracted from an electronic database were used as predictors of caregiver mastery and relationship strain, which were measured through mailed surveys. Multivariable linear regression models were used to predict caregiver mastery and relationship strain.

RESULTS: For each care manager home environment assessment, caregiver mastery increased 4 points (range 0–100, mean±standard deviation 57.1±26.6, 95% confidence interval (CI)=2.4–5.7; P=.001) between baseline and 18 months. For every action linking caregivers to community agencies for nonspecific needs, caregiver mastery decreased 6.2 points (95% CI=−8.5 to −3.9; P<.001). No other care management activities were significantly associated with this outcome, and no specific activities were associated with a change in caregiver relationship strain.

CONCLUSION: Home assessments for specific needs of caregivers and persons with dementia are associated with improvements in caregivers' sense of mastery. Future work is needed to determine whether this increase is sustained over time and decreases the need for institutionalization.
The Confusion Assessment Method: A Systematic Review of Current Usage
Authors: Wei Leslie A. , Fearing Michael A. , Sternberg Eliezer J. , Inouye Sharon K.
Published: April 2008

OBJECTIVES: To examine the psychometric properties, adaptations, translations, and applications of the Confusion Assessment Method (CAM), a widely used instrument and diagnostic algorithm for identification of delirium.

DESIGN: Systematic literature review.

SETTING: Not applicable.

MEASUREMENTS: Electronic searches of PubMED, EMBASE, PsychINFO, CINAHL, Ageline, and Google Scholar, augmented by reviews of reference listings, were conducted to identify original English‐language articles using the CAM from January 1, 1991, to December 31, 2006. Two reviewers independently abstracted key information from each article.

PARTICIPANTS: Not applicable.

RESULTS: Of 239 original articles, 10 (4%) were categorized as validation studies, 16 (7%) as adaptations, 12 (5%) as translations, and 222 (93%) as applications. Validation studies evaluated performance of the CAM against a reference standard. Results were combined across seven high‐quality studies (N=1,071), demonstrating an overall sensitivity of 94% (95% confidence interval (CI)=91–97%) and specificity of 89% (95% CI=85–94%). The CAM has been adapted for use in the intensive care unit, emergency, and institutional settings and for scoring severity and subsyndromal delirium. The CAM has been translated into 10 languages where published articles are available. In application studies, CAM‐rated delirium is most commonly used as a risk factor or outcome but also as an intervention or reference standard.

CONCLUSION: The CAM has helped to improve identification of delirium in clinical and research settings. To optimize performance, the CAM should be scored based on observations made during formal cognitive testing, and training is recommended. Future action is needed to optimize use of the CAM and to improve the recognition and management of delirium.
Association Between Unmet Needs for Medication Support and All‐Cause Hospitalization in Community‐Dwelling Disabled Elderly People
Authors: Kuzuya Masafumi , Hirakawa Yoshihisa , Suzuki Yusuke , Iwata Mitsunaga , Enoki Hiromi , Hasegawa Jun , Iguchi Akihisa
Published: April 2008

OBJECTIVES: To clarify the association between unmet medication management need and 3‐year mortality and hospitalization for community‐dwelling older people with various levels of disabilities.

DESIGN: Prospective cohort study (the Nagoya Longitudinal Study for Frail Elderly).

SETTING: Community‐based.

PARTICIPANTS: One thousand seven hundred seventy‐two community‐dwelling elderly subjects (611 men, 1,161 women).

MEASUREMENTS: Data included the clients' demographic characteristics, a rating for basic and instrumental activities of daily living (ADLs), number of prescribed medications and physician‐diagnosed chronic diseases, medication adherence, ability to manage medication, and presence or absence of medication assistance. Cox proportional hazard models and the Kaplan‐Meier method were used to assess the association between the medication management at baseline and mortality or hospitalization during a 3‐year period.

RESULTS: Of 1,772 participants, 681 reported no difficulty with self‐medication management, and 1,091 experienced difficulty with self‐medication. Of participants with difficulty with self‐medication management, 929 had medication assistance, and 162 did not. During a 3‐year follow up, 424 participants died, and 758 were admitted to hospitals. The baseline data demonstrated that participants not receiving medication assistance were younger and had better ADL status and fewer comorbidities. Multivariate Cox regression models adjusting for potential confounders showed that the lack of assistance in those who needed medication assistance was associated with hospitalization but not mortality during the study period.

CONCLUSION: In community‐dwelling disabled elderly people, lack of medication assistance in those needing medication support was associated with higher risk of hospitalization.
Dual Use of Bladder Anticholinergics and Cholinesterase Inhibitors: Long‐Term Functional and Cognitive Outcomes
Authors: Sink Kaycee M. , Thomas Joseph , Xu Huiping , Craig Bruce , Kritchevsky Steven , Sands Laura P.
Published: April 2008

OBJECTIVES: To determine the cognitive and functional consequences of dual use of cholinesterase inhibitors (ChIs) and the bladder anticholinergics oxybutynin or tolterodine.

DESIGN: Prospective cohort study.

SETTING: Nursing homes (NHs) in the state of Indiana.

PARTICIPANTS: Three thousand five hundred thirty‐six Medicaid‐eligible NH residents aged 65 and older taking a ChI between January 1, 2003, and December 31, 2004. Residents were excluded if they were taking an anticholinergic other than oxybutynin or tolterodine.

MEASUREMENTS: Indiana Medicaid claims data were merged with data from the Minimum Data Set (MDS). Repeated‐measures analyses were performed to assess the effects of dual therapy on change in cognitive function measured using the MDS Cognition Scale (MDS‐COGS; scored 0–10) and change in activity of daily living (ADL) function using the seven ADL items in the MDS (scored 0–28). Potential covariates included age, sex, race, number of medications, and Charlson Comorbidity Index score.

RESULTS: Three hundred seventy‐six (10.6%) residents were prescribed oxybutynin or tolterodine concomitantly with a ChI. In residents in the top quartile of ADL function, ADL function declined an average of 1.08 points per quarter when not taking bladder anticholinergics (ChI alone), compared with 1.62 points per quarter when taking dual therapy, a 50% greater rate in quarterly decline in ADL function (P=.01). There was no excess decline attributable to dual therapy in MDS‐COGS scores or in ADL function for residents who started out with lower functioning.

CONCLUSION: In higher‐functioning NH residents, dual use of ChIs and bladder anticholinergics may result in greater rates of functional decline than use of ChIs alone. The MDS‐COGS may not be sensitive enough to detect differences in cognition due to dual use.
The Effects of Total Hip Arthroplasty on Physical Functioning in the Older Population
Authors: George Linda K. , Ruiz David , Sloan Frank A.
Published: April 2008

OBJECTIVES: To estimate the effects of total hip arthroplasty (THA) on three levels of physical functioning in a representative national sample of older adults.

DESIGN: Survey.

SETTING: Participants were interviewed in their homes.

PARTICIPANTS: Participants consisted of stratified random samples of Medicare beneficiaries interviewed between 1992 and 2003.

METHODS: Data from the Medicare Current Beneficiary Survey from 1992 to 2003 and merged Medicare claims data identified participants who received (n=131) or did not receive (n=257) THA. Outcomes were three measures of physical functioning: Nagi items, instrumental activities of daily living, and activities of daily living. Baseline and follow‐up measures were obtained approximately 6 months apart. Logistic regression was used to predict the effects of THA on functioning, with a wide range of covariates controlled.

RESULTS: Persons who received THA significantly improved in two of three levels of physical functioning; the no‐treatment group experienced declines in physical functioning.

CONCLUSION: Receipt of THA is associated with significant improvements in two levels of physical functioning. These benefits are broadly applicable in that a wide variety of covariates had minimal effects on THA receipt and outcome.
Which Shorts Are Informed?
Authors: BOEHMER EKKEHART , JONES CHARLES M. , ZHANG XIAOYAN
Published: April 2008

We construct a long daily panel of short sales using proprietary NYSE order data. From 2000 to 2004, shorting accounts for more than 12.9% of NYSE volume, suggesting that shorting constraints are not widespread. As a group, these short sellers are well informed. Heavily shorted stocks underperform lightly shorted stocks by a risk‐adjusted average of 1.16% over the following 20 trading days (15.6% annualized). Institutional nonprogram short sales are the most informative; stocks heavily shorted by institutions underperform by 1.43% the next month (19.6% annualized). The results indicate that, on average, short sellers are important contributors to efficient stock prices.
Do Bankruptcy Codes Matter? A Study of Defaults in France, Germany, and the U.K.
Authors: DAVYDENKO SERGEI A. , FRANKS JULIAN R.
Published: April 2008

Using a sample of small firms that defaulted on their bank debt in France, Germany, and the United Kingdom, we find that large differences in creditors' rights across countries lead banks to adjust their lending and reorganization practices to mitigate costly aspects of bankruptcy law. In particular, French banks respond to a creditor‐unfriendly code by requiring more collateral than lenders elsewhere, and by relying on collateral forms that minimize the statutory dilution of their claims in bankruptcy. Despite such adjustments, bank recovery rates in default remain sharply different across the three countries, reflecting very different levels of creditor protection.
An Empirical Analysis of the Pricing of Collateralized Debt Obligations
Authors: LONGSTAFF FRANCIS A. , RAJAN ARVIND
Published: April 2008

We use the information in collateralized debt obligations (CDO) prices to study market expectations about how corporate defaults cluster. A three‐factor portfolio credit model explains virtually all of the time‐series and cross‐sectional variation in an extensive data set of CDX index tranche prices. Tranches are priced as if losses of 0.4%, 6%, and 35% of the portfolio occur with expected frequencies of 1.2, 41.5, and 763 years, respectively. On average, 65% of the CDX spread is due to firm‐specific default risk, 27% to clustered industry or sector default risk, and 8% to catastrophic or systemic default risk.
Identification of Maximal Affine Term Structure Models
Authors: COLLIN‐DUFRESNE PIERRE , GOLDSTEIN ROBERT S. , JONES CHRISTOPHER S.
Published: April 2008

Building on Duffie and Kan (1996), we propose a new representation of affine models in which the state vector comprises infinitesimal maturity yields and their quadratic covariations. Because these variables possess unambiguous economic interpretations, they generate a representation that is globally identifiable. Further, this representation has more identifiable parameters than the “maximal” model of Dai and Singleton (2000). We implement this new representation for select three‐factor models and find that model‐independent estimates for the state vector can be estimated directly from yield curve data, which present advantages for the estimation and interpretation of multifactor models.
Competition from Specialized Firms and the Diversification–Performance Linkage
Authors: SANTALO JUAN , BECERRA MANUEL
Published: April 2008

In this study, we show that the effect of diversification on performance is not homogeneous across industries and explore analytically and empirically the implications of this finding for the diversification literature. Diversified firms perform better in industries with a small number of nondiversified competitors or, equivalently, when specialized firms have a small combined market share, but worse as the presence of specialized firms increases in the industries in which they compete. The results are robust to the use of methods that alleviate the self‐selection problem and call for a reassessment of the diversification–performance relationship.
Correlated Trading and Returns
Authors: DORN DANIEL , HUBERMAN GUR , SENGMUELLER PAUL
Published: April 2008

A German broker's clients place similar speculative trades and therefore tend to be on the same side of the market in a given stock during a given day, week, month, and quarter. Aggregate liquidity effects, short sale constraints, the systematic execution of limit orders (coordinated through price movements) or the correlated trading of other investors who pick off retail limit orders do not fully explain why retail investors trade similarly. Correlated market orders lead returns, presumably due to persistent speculative price pressure. Correlated limit orders also predict subsequent returns, consistent with executed limit orders being compensated for accommodating liquidity demands.
Earnings Management and Firm Performance Following Open‐Market Repurchases
Authors: GONG GUOJIN , LOUIS HENOCK , SUN AMY X.
Published: April 2008

Both post‐repurchase abnormal returns and reported improvement in operating performance are driven, at least in part, by pre‐repurchase downward earnings management rather than genuine growth in profitability. The downward earnings management increases with both the percentage of the company that managers repurchase and CEO ownership. Pre‐repurchase abnormal accruals are also negatively associated with future performance, with the association driven mainly by those firms that report the largest income‐decreasing abnormal accruals. The study suggests that one reason firms experience post‐repurchase abnormal returns is that post‐repurchase realized earnings growth exceeds expectations formed on the basis of pre‐repurchase deflated earnings numbers.