bluuebunny/crossref_metadata_2025 huggingface dataset:
The effect of electrical stimulation of the corticospinal tract on motor units of the human biceps brachii
Authors: Petersen Nicolas T. , Taylor Janet L. , Gandevia Simon C.
Published: September 2002

In healthy human subjects, descending motor pathways including the corticospinal tract were stimulated electrically at the level of the cervicomedullary junction to determine the effects on the discharge of motoneurones innervating the biceps brachii. Post‐stimulus time histograms (PSTHs) were constructed for 15 single motor units following electrical stimulation of the corticospinal tract and for 11 units following electrical stimulation of large diameter afferents at the brachial plexus. Responses were assessed during weak voluntary contraction. Both types of stimulation produced a single peak at short latency in the PSTH (mean 8.5 and 8.7 ms, respectively) and of short duration (< 1.4 ms). In separate studies, we compared the latency of the responses to electrical stimulation of the corticospinal tract in the relaxed muscle with that in the contracting muscle. The latency was the same in the two conditions when the intensity of the stimulation was adjusted so that responses of the same size could be compared. Estimates of the descending conduction velocity and measurements of presumed peripheral conduction time suggest that there is less than 0.5 ms for spinal events (including synaptic delays). We propose that in response to electrical stimulation of the descending tract fibres, biceps motoneurones receive a large excitatory input with minimal dispersion and it presumably contains a dominant monosynaptic component.
The ethical problem of false positives: a prospective evaluation of physician reporting in the medical record
Authors: Dresselhaus T R , Luck J , Peabody J W
Published: September 2002

Objective:To determine if the medical record might overestimate the quality of care through false, and potentially unethical, documentation by physicians.

Design:Prospective trial comparing two methods for measuring the quality of care for four common outpatient conditions: (1) structured reports by standardised patients (SPs) who presented unannounced to the physicians’ clinics, and (2) abstraction of the medical records generated during these visits.

Setting:The general medicine clinics of two veterans affairs medical centres.

Participants:Twenty randomly selected physicians (10 at each site) from among eligible second and third year internal medicine residents and attending physicians.

Main measurements:Explicit criteria were used to score the medical records of physicians and the reports of SPs generated during 160 visits (8 cases × 20 physicians). Individual scoring items were categorised into four domains of clinical performance: history, physical examination, treatment, and diagnosis. To determine the false positive rate, physician entries were classified as false positive (documented in the record but not reported by the SP), false negative, true positive, and true negative.

Results:False positives were identified in the medical record for 6.4% of measured items. The false positive rate was higher for physical examination (0.330) and diagnosis (0.304) than for history (0.166) and treatment (0.082). For individual physician subjects, the false positive rate ranged from 0.098 to 0.397.

Conclusions:These data indicate that the medical record falsely overestimates the quality of important dimensions of care such as the physical examination. Though it is doubtful that most subjects in our study participated in regular, intentional falsification, we cannot exclude the possibility that false positives were in some instances intentional, and therefore fraudulent, misrepresentations. Further research is needed to explore the questions raised but incompletely answered by this research.
The validity of contracts to dispose of frozen embryos
Authors: Pennings G
Published: September 2002

The widespread abandonment of frozen embryos by the gamete providers or intentional parents urgently demands a solution. Most centres react by requiring patients to enter a prior agreement governing the future disposition of their embryos in all foreseeable circumstances. These dispositional directives are inappropriate and self defeating in the event of contingencies in which the patients remain competent to execute an updated directive. Internal and external changes may invalidate the prior directive by altering the situation as represented by the couple at the initiation of treatment to such an extent that it no longer corresponds with the actual situation at the time of the execution of the disposition. The prior agreement should only be considered binding if the agreement among the partners on a specific option was a material condition for one of the partners to start treatment.
Increasing use of DNR orders in the elderly worldwide: whose choice is it?
Authors: Cherniack E P
Published: September 2002

Most elderly patients die with an order in place that they not be given cardiopulmonary resuscitation (DNR order). Surveys have shown that many elderly in different parts of the world want to be resuscitated, but may lack knowledge about the specifics of cardiopulmonary resuscitation (CPR). Data from countries other than the US is limited, but differences in physician and patient opinions by nationality regarding CPR do exist. Physicians’ own preferences for CPR may predominate in the DNR decision making process for their patients, and many physicians may not want the participation of the elderly or believe that it is necessary. More complete and earlier discussions of a wider range of options of care for patients at the end of life have been advocated. The process ought to include education for patients about the process and efficacy of CPR, and for physicians on how to consider the values and levels of knowledge of their patients, whose preferences may differ from their own.
Why we should not seek individual informed consent for participation in health services research
Authors: Cassell J , Young A
Published: September 2002

Ethics committees now require that individuals give informed consent to much health services research, in the same way as for clinical research. This is misguided. Existing ethical guidelines do not help us decide how to seek consent in these cases, and have allowed managerial experimentation to remain largely unchecked. Inappropriate requirements for individual consent can institutionalise health inequalities and reduce access to services for vulnerable groups. This undermines the fundamental purpose of the National Health Service (NHS), and ignores our rights and duties as its members, explored here. Alternative forms of community consent should be actively pursued.
A review of functional status measures for workers with upper extremity disorders
Authors: Salerno D F , Copley-Merriman C , Taylor T N , Shinogle J , Schulz R M
Published: September 2002

In order to identify functional status measures for epidemiological studies among workers with mild to moderate disorders of the neck and upper extremity, a literature search was conducted for the years 1966 to 2001. Inclusion criteria were: (1) relevance to neck and upper extremity; (2) assessment among workers; and (3) relevance to mild to moderate disorders. Of 13 instruments reviewed, six measures were tested among workers. The three best measures, depending on the purpose of research, included the standardised Nordic Musculoskeletal Questionnaire, the Upper Extremity Questionnaire, and the Neck and Upper Limb Instrument. Development of a functional protocol is regarded as a realistic enhancement for research of neck and upper extremity disorders in the workplace. For research and clinical practice, measures of functional status, sensitive enough to measure the subtle conditions in mild to moderate disorders, may provide prognostic information about the risk of developing musculoskeletal disorders in apparently healthy patients. Appropriate use of functional status questionnaires is imperative for a meaningful portrayal of health.
Working hours spent on repeated activities and prevalence of back pain
Authors: Guo H-R
Published: September 2002

Background and Aims:Back pain is the most common reason for filing workers' compensation claims in the United States and affects large numbers of workers in many other countries. To evaluate the associations between working hours spent on repeated activities and back pain, data gathered through the 1988 National Health Interview Survey were analysed. The data were also used to identify high risk occupations.

Methods:A total of 30 074 workers participated in the survey. They were asked to provide information on their job, including the time spent on repeated strenuous physical activities (RSPA) and the time spent on repeated bending, twisting, or reaching (RBTR) on a typical job. A case of back pain was defined as a worker who had back pain every day for a week or more during the past 12 months. Each case was asked to report the cause of back pain. Those who attributed their back pain to repeated activities (RA) or a single accident or injury (AI) were asked to recall whether they performed RA or had the AI at work.

Results:Whereas the prevalence of back pain increased as the number of working hours spent on RSPA or RBTR increased, the dose–response relations were not linear for either factor, suggesting the involvement of other unmeasured factors. The estimated overall prevalence of RA back pain was 8.9% among male workers and 5.9% among female workers. “Carpenters” had the highest prevalence (19.2%) and most cases (338 000) among the major occupations of men, and “nursing aides, orderlies, and attendants” had the highest prevalence (15.2%) and most cases (217 000) among the major occupations of women.

Conclusions:The number of hours spent on repeated activities at work was associated with the prevalence of back pain. This study identified high risk occupations for future research and intervention.
Workers’ understanding of chemical risks: electroplating case study
Authors: Sadhra S , Petts J , McAlpine S , Pattison H , MacRae S
Published: September 2002

Background:There is limited research concerning how small companies in particular, respond to health and safety messages.

Aims:To understand individuals’ knowledge and beliefs about chemical risks and to compare these with those of experts.

Methods:The use of chromic acid in particular, and also other chemicals associated with chrome plating were studied. All chromium plating firms were based in the West Midlands. The methodology involved initial face to face interviews (n = 21) with chromium platers, structured questionnaires (n = 84) to test the prevalence of beliefs identified in the interviews, an expert questionnaire, and a workshop to discuss findings. The responses of platers were compared with those of occupational health and safety experts.

Results:Although chromium platers appeared to understand the short term adverse effects of the chemicals to which they are exposed, their understanding of long term, or chronic effects appeared to be incomplete. They had good knowledge of acute effects based primarily on experience. Platers were aware of the hazardous nature of the chemicals with which they work, but did not draw distinction between the terms “hazards” and “risks”. They had difficulties articulating the effects of the chemicals and how exposure might occur; although it is inappropriate to equate this with lack of knowledge. A significant minority of platers displayed deficiencies in understanding key technical terms used in Safety Data Sheets.

Conclusions:This study provides a method which can be used to gain some understanding of workers’ knowledge and beliefs about risks that they are exposed to in the workplace. The study also identifies gaps between the platers’ knowledge and beliefs and those of experts. New risk information needs to be designed which addresses the information needs of platers using language that they understand.
Effectiveness of the hands-free technique in reducing operating theatre injuries
Authors: Stringer B , Infante-Rivard C , Hanley J A
Published: September 2002

Background:Operating theatre personnel are at increased risk for transmission of blood borne pathogens when passing sharp instruments. The hands-free technique, whereby a tray or other means are used to eliminate simultaneous handling of sharp instruments, has been recommended.

Aims:To prospectively evaluate the effectiveness of the hands-free technique in reducing the incidence of percutaneous injuries, contaminations, and glove tears arising from handling sharp instruments.

Methods:For each of 3765 operations carried out in main and surgical day care operating theatres in a large urban hospital, over six months, circulating nurses recorded the proportion of use of the hands-free technique during each operation, as well as other features of the operation. The hands-free technique, considered to be used when 75% or more of the passes in an operation were done in this way, was used in 42% of operations. The relative rate of incidents (percutaneous injuries, contaminations, and glove tears) in operations where the hands-free technique was used and not used, with adjustment via multiple logistic regression for the different risk profiles of the two sets of operations, was calculated.

Results:A total of 143 incidents (40 percutaneous injuries, 51 contaminations, and 52 glove tears) were reported. In operations with greater than 100 ml blood loss, the incident rate was 4% (18/486) when the hands-free technique was used and 10% (90/880) when it was not, approximately 60% less. When adjusted for differences in type and duration of surgery, emergency status, noisiness, time of day, and number present for 75% of the operation, the reduction in the rate was 59% (95% CI 23% to 72%). In operations with less than 100 ml blood loss, the corresponding rates were 1.4% (15/1051) when the hands-free technique was used and 1.5% (19/1259) when it was not used. Adjustment for differences in risk factors did not alter the difference.

Conclusions:Although not effective in all operations, use of the hands-free technique was effective in operations with more substantial blood loss.
How informed is consent? Understanding of pictorial and verbal probability information by medical inpatients
Authors: Fuller R , Dudley N , Blacktop J
Published: September 2002

Understanding probability information about treatment risks and benefits is a vital component of patients’ decision making capacity. This study demonstrates extensive misunderstanding of verbal descriptions of probability by medical inpatients of all ages, questioning the extent of their capacity for giving informed consent. Pictorial descriptions of probability were well understood, suggesting their adoption into clinical practice.
Transient disappearance of left bundle branch block pattern: an unusual ECG presentation of acute pulmonary embolism
Authors: Athar S M , Chin B S P , Flint E J
Published: September 2002

A 61 year old man developed acute pulmonary embolism while in hospital. His previous and admission electrocardiograms (ECGs) showed a typical left bundle branch block (LBBB) pattern. Immediately after the onset of acute pulmonary embolism, LBBB disappeared from his body surface ECG with sinus bradycardia, normalisation of QRS duration, prolonged QT interval, and marked T abnormalities to the right precordial leads. Recovery from pulmonary embolism resulted in reappearance of his left bundle branch pattern. Delayed conduction of the previously unaffected right bundle branch resulting in roughly equivalent onset of ventricular activation is the most likely reason. Rate dependent LBBB is also discussed.
An unusual case of gestational diabetes mellitus
Authors: Shankar P , Sundarka M K , Sundarka A
Published: September 2002

The case of a woman, who developed gestational diabetes at six weeks in two successive pregnancies, is reported. She was in the high risk group to develop gestational diabetes. The first pregnancy terminated in abortion at 10 weeks. In the second pregnancy, institution of insulin therapy at diagnosis was associated with a successful outcome. This case highlights the need for screening for gestational diabetes at the first antenatal visit in the high risk group.
Enzyme replacement therapy in the management of longstanding skeletal and soft tissue salmonella infection in a patient with Gaucher’s disease
Authors: Margalit M , Ash N , Zimran A , Halkin H
Published: September 2002

A splenectomised patient with Gaucher’s disease who developed multiple foci of osteomyelitis and soft tissue abcesses, after a severe episode of group C salmonella sepsis, is described. Aggressive antibiotic treatment and surgical drainage had little effect and the patient’s condition continued to deteriorate. With initiation of enzyme replacement therapy (ERT) in addition to specific antibiotic treatment, defervescence and gradual healing occurred. Complete resolution of the infection was seen after 15 months. The possible role of ERT in healing bacterial infections in Gaucher’s disease is discussed.
Shear modulus and damping of soft Bangkok clays
Authors: Teachavorasinskun Supot , Thongchim Pipat , Lukkunaprasit Panitan
Published: September 2002

The shear modulus and damping ratio of undisturbed Bangkok clay samples were measured using a cyclic triaxial apparatus. Although abundant literature on this topic exists, selection of the most suitable empirical correlation for a seismic analysis cannot be done unless site specific data are obtained. The apparatus used in this research can measure the stressstrain relationships from strain levels of about 0.01%. The equivalent shear modulus measured at these strains was about 80% of the value obtained from the shear wave velocity measurements. The degradation curves of the equivalent shear modulus fell into the ranges reported in the literature, for clay having similar plasticity. The damping ratios varied from about 45% at small strains (0.01%) to about 2530% at large strains (10%). The effects of load frequency and cyclic stress history on the shear modulus and damping ratio were also investigated. An increase in load frequency from 0.1 to 1.0 Hz had no influence on the shear modulus characteristic, but it did result in a slight decrease in the damping ratio. The effects of the small amplitude cyclic stress history on the subsequently measured shear modulus and damping ratio were almost negligible when the changes in void ratio were taken into account.Key words: soft clay, shear modulus, damping ratio, cyclic triaxial test, cyclic stress history.
Effect of permeating solutions on complex permittivity of compacted clay
Authors: Rowe R K , Shang J Q , Xie Y
Published: September 2002

The complex permittivity of a natural clayey till (Halton Till) is measured before and after permeating with four different ionic contaminant solutions (CaCl2, MgCl2, NaCl, and acetic acid) to examine the effects of contaminant type and concentration on the complex permittivity of contaminated soil. The complex permittivity at 250 MHz is most sensitive to the concentration of the ions in the pore fluid, and a good linear correlation is obtained between the real and the imaginary parts of the complex permittivity and the concentrations of the anions, including chloride and acetate. These anions are distinguished by their own unique relationships for the simple solutions examined. Linear relationships also exist between the real and the imaginary parts of the complex permittivity and all of the cation species in the simple chloride salt solutions, namely Ca2+, Mg2+, and Na+. The results provide the evidence that the complex permittivity of soils may be used to identify changes in soil pore-water chemistry. As such, it may have potential for use in the detection of soil contamination.Key words: environmental, dielectric, detection, contamination, waste management.
Transition of soil friction during suction pile installation
Authors: Cho Y , Bang S , Preber T
Published: September 2002

A series of laboratory model tests on the suction pile installation in sand have been conducted to obtain the relationship between the applied suction pressure inside the pile and the resulting pile penetration. The relationships have been used to estimate the mobilized soil strength during the pile installation. This reduction in the soil strength due to the applied suction pressure is described as a function of a nondimensional parameter to characterize the variation and transition of the soil strength during the pile installation. The nondimensional parameter includes all pertinent pile and soil properties that are thought to affect the behavior of the suction pile during installation.Key words: suction pile, suction pressure, mobilized effective soil friction angle.
Influence of suction on the strength and stiffness of compacted sandbentonite
Authors: Blatz J A , Graham J , Chandler N A
Published: September 2002

This paper examines the constitutive behaviour of unsaturated mixtures of compacted sand-bentonite material. Two different techniques have been used to modify soil suction in laboratory specimens to examine the influence of suction on the behaviour of compacted materials. The two methods generated inherent differences in material fabric and therefore in stress-strain behaviour. The difference in microstructure generated by these two preparation techniques created different properties for the two series of specimens. This paper compares the behaviour of the two series of specimens and relates the observed mechanical behaviour to the initial soil fabric created by the two different preparation techniques. Specimens of similar compacted material were taken from two full-scale in-ground experiments conducted at Atomic Energy of Canada Limited's Underground Research Laboratory at Lac du Bonnet, Manitoba and sheared using the same triaxial equipment. The results are compared to the results of shearing laboratory compacted specimens. The research program demonstrates the need to understand the initial volume and suction states of plastic clays in order to predict the change in mechanical behaviour following a change in water content.Key words: constitutive relationships, unsaturation, laboratory tests, expansive soils, clays, shear strength.
Measurement of soil-water characteristic curves for fine-grained soils using a small-scale centrifuge
Authors: Khanzode R M , Vanapalli S K , Fredlund D G
Published: September 2002

Considerably long periods of time are required to measure soil-water characteristic curves using conventional equipment such as pressure plate apparatus or a Tempe cell. A commercially available, small-scale medical centrifuge with a swinging type rotor assembly was used to measure the soil-water characteristic curves on statically compacted, fine-grained soil specimens. A specimen holder was specially designed to obtain multiple sets of water content versus suction data for measuring the soil-water characteristic curve at a single speed of rotation of the centrifuge. The soil-water characteristic curves were measured for three different types of fine-grained soils. The three soils used in the study were processed silt (liquid limit, wL = 24%; plasticity index, Ip = 0; and clay = 7%), Indian Head till (wL = 35.5%, Ip = 17%, and clay = 30%), and Regina clay (wL = 75.5%, Ip = 21%, and clay = 70%). The soil-water characteristic curves for the above soils were measured in 0.5, 1, and 2 days, respectively, using the centrifuge technique for suction ranges from 0 to 600 kPa. Time periods of 2, 46, and 16 weeks were required for measuring the soil-water characteristic curves for the same soils using a conventional pressure plate apparatus. There is reasonably good agreement between the experimental results obtained by the centrifuge and the pressure plate methods. The results of this study are encouraging as soil-water characteristic curves can be measured in a reduced time period when using a small-scale centrifuge.Key words: unsaturated soils, soil-water characteristic curve, centrifuge technique, soil suction, matric suction, water content.
Hydraulic conductivity of compacted tills from northern Quebec
Authors: Leroueil Serge , Le Bihan Jean-Pierre , Sebaihi Samira , Alicescu Viad
Published: September 2002

The hydraulic conductivity of six compacted tills from northern Quebec with different grain-size distributions has been studied in saturated conditions in the laboratory. The results show that compaction conditions play an important role in hydraulic conductivity. When considering the hydraulic conductivities of specimens compacted at degrees of saturation greater than the optimum, there is a good correlation with the content of clay-size particles. This paper provides a good practical tool for evaluating preliminary hydraulic conductivity values of compacted tills from northern Quebec on the basis of their grain-size distribution and compaction conditions.Key words: till, hydraulic conductivity, grain-size distribution, compaction conditions.
ON ARCHIMEDEAN LINK COMPLEMENTS
Authors: AITCHISON IAIN R. , REEVES LAWRENCE D.
Published: September 2002

We study a subclass of alternating links for which the complete hyperbolic metric can be realised directly by pairwise identification of faces of two ideal hyperbolic polyhedra. Our main result is a characterization of these links: essentially, the corresponding polyhedra are exactly the Archimedean solids with trivalent vertices. Furthermore, we show that the only knots which arise are the two dodecahedral knots, and the figure eight knot.
CYCLIC AND FINITE SURGERIES ON PRETZEL KNOTS
Authors: MATTMAN THOMAS W.
Published: September 2002

We classify Dehn surgeries on (p,q,r) pretzel knots resulting in a manifold M(α) having cyclic fundamental group and analyze those leading to a finite fundamental group. The proof uses the theory of cyclic and finite surgeries developed by Culler, Shalen, Boyer, and Zhang. In particular, Culler-Shalen seminorms play a central role.
ARITHMETIC KNOTS IN CLOSED 3-MANIFOLDS
Authors: BAKER M. D. , REID A. W.
Published: September 2002

Let Od denote the ring of integers in [Formula: see text]. An orientable finite volume cusped hyperbolic 3-manifold M is called arithmetic if the faithful discrete representation of π1(M) into PSL(2,C) is conjugate to a group commensurable with some Bianchi group PSL (2,Od). If M is a closed orientable 3-manifold, we say a link L ⊂ M is arithmetic if M\L is arithmetic.

In the paper, we show that there exist closed orientable 3-manifolds which do not contain anarithmetic knot. Our methods give much more precise informations for non-hyperbolic 3-manifolds. For certain Lens Spaces, we can give fairly complete statements.
ORIENTED DIVIDES AND PLANE CURVE BRAIDS
Authors: GIBSON WILLIAM
Published: September 2002

This paper begins with a review of the extension of A'Campo's divides to the more general construction of oriented divides, using the same disk model of S3. It is shown that all links in S3 can be represented by oriented divides (in contrast with divide links) and simple methods are presented for moving between links and their oriented divide presentations.

Using the properties of the disk model, oriented divides are extended by three extra equivalence rules, and it is shown that this extended theory of oriented divides is equivalent to knot theory in S3. Fueled by this result, the concept of oriented divide braid is introduced, together with a group construction which parallels the classical braid group representation of geometric braids. This leads to results analagous to Alexander's well-known theorem concerning braid presentations, and also the Markov theorem.
Different Mechanisms of Increased Luminal Stenosis After Arterial Injury in Mice Deficient for Urokinase- or Tissue-Type Plasminogen Activator
Authors: Schäfer Katrin , Konstantinides Stavros , Riedel Carsten , Thinnes Therese , Müller Katja , Dellas Claudia , Hasenfuss Gerd , Loskutoff David J.
Published: September 2002

Background—

Tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) are thought to play critical roles in vascular remodeling after injury, with tPA mediating intravascular clot lysis and uPA modulating cell migration within the vessel wall. In human vascular disease, however, thrombus organization and neointimal formation are closely interrelated processes. This study examines the differential roles of tPA and uPA in these processes in mice.

Methods and Results—

Carotid artery injury and thrombosis were induced in wild-type (WT), uPA-deficient (uPA
−/−
), and tPA-deficient (tPA
−/−
) mice with the use of ferric chloride. The expression of uPA and tPA was significantly upregulated in the vessel wall of WT mice 1 week after injury, and compared with WT mice, uPA
−/−
and tPA
−/−
mice had lower carotid patency rates after injury. At 3 weeks, only 55% of uPA
−/−
mouse vessels were patent compared with 81% in tPA
−/−
mice and 100% in WT mice (
P
=0.014). Morphometric analysis of injured arterial segments revealed severe luminal stenosis (62±28%) in uPA
−/−
mice compared with their tPA
−/−
(16±12%) and WT (6.3±3.6%,
P
<0.001) counterparts. Moreover, although the vascular walls of WT mice and, particularly, tPA
−/−
mice developed a cell-rich multilayered neointima and media, the lumen of uPA
−/−
vessels remained obstructed with acellular unorganized thrombotic material, and their medial areas did not expand.

Conclusions—

These results indicate that the roles of uPA and tPA in the arterial response to injury are different and more complex than previously assumed and emphasize the critical role of thrombus organization and resolution in neointimal formation and vascular pathology.
Smooth Muscle Cells in Transplant Atherosclerotic Lesions Are Originated From Recipients, but Not Bone Marrow Progenitor Cells
Authors: Hu Yanhua , Davison Fergus , Ludewig Burkhard , Erdel Martin , Mayr Manuel , Url Manfred , Dietrich Hermann , Xu Qingbo
Published: September 2002

Background—

Smooth muscle cell (SMC) accumulation in the intima of vessels is a key event in the pathogenesis of transplant atherosclerosis. The traditional hypothesis that SMCs in the lesion are derived from the media of the donor vessel has been challenged by recent observations, but the cell origin is still not well established.

Methods and Results—

Here, we use a simplified model of artery allografts in transgenic mice to clearly identify the source of SMCs in transplant atherosclerosis. Aortic segments donated by BALB/c mice allografted to ROSA26 (C57B/6) mice expressing β-galactosidase (gal) in all tissues showed that neointimal cells derived exclusively from host cells. It was also demonstrated that SMCs of neointimal and atherosclerotic lesions in vessels allografted to mice expressing β-gal only in SMCs (SM-LacZ) or to apoE-deficient/SM-LacZ mice originated from the recipient, and not donor vessels. Interestingly, bone marrow transplantation of SM-LacZ β-gal–expressing cells into aortic allograft recipients revealed completely negative β-gal staining of neointimal and atherosclerotic lesions. However, a population of β-gal–positive cells in lesions of allografts was observed in chimeric mice with ROSA26 β-gal–expressing marrow cells. When bone marrow cells from both ROSA26 and SM-LacZ mice were cultured and stimulated with platelet-derived growth factor-BB, α-actin and β-gal double-positive cells were found, suggesting that bone marrow cells have an ability to differentiate into SMCs.

Conclusions—

Thus, we provide strong evidence that SMCs of neointimal and atherosclerotic lesions in allografts are derived from the recipients and that non–bone marrow–derived progenitor cells are a possible source of SMCs in atherosclerotic lesions.
Two Types of Ventricular Fibrillation in Isolated Rabbit Hearts
Authors: Wu Tsu-Juey , Lin Shien-Fong , Weiss James N. , Ting Chih-Tai , Chen Peng-Sheng
Published: September 2002

Background—

The combined effects of excitability and action potential duration (APD) restitution on wavefront dynamics remain unclear.

Methods and Results—

We used optical mapping techniques to study Langendorff-perfused rabbit hearts. In protocol IA (n=10), D600 at increasing concentrations was infused during ventricular fibrillation (VF). With concentration increased to 0.5 mg/L, fast VF (dominant frequency, 19.1±1.8 Hz) was consistently converted to ventricular tachycardia (VT). However, increasing D600 further to 2.5 or 5.0 mg/L converted VT to slow VF (11.9±2.3 Hz,
P
=0.0011). In an additional 4 hearts (protocol IB), tetrodotoxin converted a preexisting VT to slow VF (11.0±1.4 Hz). Optical maps show wandering wavelets in fast VF, organized reentry in VT, and spatiotemporal periodicity in slow VF. In protocol II, we determined APD and conduction time
−1
(CT
−1
) restitutions during D600 infusion. CT
−1
was used as an estimate of excitability. At 0.1 mg/L, APD and CT
−1
restitutions were steep and flat, respectively. APD restitution became flattened when D600 increased to 0.5 mg/L, converting fast VF to VT. Further increasing D600 to 2.5 or 5.0 mg/L steepened CT
−1
restitution and widened the range of S
1
pacing cycle lengths over which CT
−1
decreased, converting VT to slow VF.

Conclusions—

Two types of VF exist in isolated rabbit hearts. Fast (type I) VF is associated with a steep APD restitution, a flat CT
−1
restitution, and wandering wavelets. Slow (type II) VF is associated with a flat APD restitution, a steep CT
−1
restitution, and spatiotemporal periodicity. Both excitability and APD restitution are important in VF maintenance.
Urinary Albumin Excretion Predicts Cardiovascular and Noncardiovascular Mortality in General Population
Authors: Hillege Hans L. , Fidler Vaclav , Diercks Gilles F.H. , van Gilst Wiek H. , de Zeeuw Dick , van Veldhuisen Dirk J. , Gans Rijk O.B. , Janssen Wilbert M.T. , Grobbee Diederick E. , de Jong Paul E.
Published: September 2002

Background—

For the general population, the clinical relevance of an increased urinary albumin excretion rate is still debated. Therefore, we examined the relationship between urinary albumin excretion and all-cause mortality and mortality caused by cardiovascular (CV) disease and non-CV disease in the general population.

Methods and Results—

In the period 1997 to 1998, all inhabitants of the city of Groningen, the Netherlands, aged between 28 and 75 years (n=85 421) were sent a postal questionnaire collecting information about risk factors for CV disease and CV morbidity and a vial to collect an early morning urine sample for measurement of urinary albumin concentration (UAC). The vital status of the cohort was subsequently obtained from the municipal register, and the cause of death was obtained from the Central Bureau of Statistics. Of these 85 421 subjects, 40 856 (47.8%) responded, and 40 548 could be included in the analysis. During a median follow-up period of 961 days (maximum 1139 days), 516 deaths with known cause were recorded. We found a positive dose-response relationship between increasing UAC and mortality. A higher UAC increased the risk of both CV and non-CV death after adjustment for other well-recognized CV risk factors, with the increase being significantly higher for CV mortality than for non-CV mortality (
P
=0.014). A 2-fold increase in UAC was associated with a relative risk of 1.29 for CV mortality (95% CI 1.18 to 1.40) and 1.12 (95% CI 1.04 to 1.21) for non-CV mortality.

Conclusions—

Urinary albumin excretion is a predictor of all-cause mortality in the general population. The excess risk was more attributable to death from CV causes, independent of the effects of other CV risk factors, and the relationship was already apparent at levels of albuminuria currently considered to be normal.
Emotional and Physical Precipitants of Ventricular Arrhythmia
Authors: Lampert Rachel , Joska Tammy , Burg Matthew M. , Batsford William P. , McPherson Craig A. , Jain Diwakar
Published: September 2002

Background—

Observational studies have suggested that psychological stress increases the incidence of sudden cardiac death. Whether emotional or physical stressors can trigger spontaneous ventricular arrhythmias in patients at risk has not been systematically evaluated.

Methods and Results—

Patients with implantable cardioverter-defibrillators (ICDs) were given diaries to record levels of defined mood states and physical activity, using a 5-point intensity scale, during 2 periods preceding spontaneously occurring ICD shocks (0 to 15 minutes and 15 minutes to 2 hours) and during control periods 1 week later. ICD-stored electrograms confirmed the rhythm at the time of shock. A total of 107 confirmed ventricular arrhythmias requiring shock were reported by 42 patients (33 men; mean age, 65 years; 78% had coronary artery disease) between August 1996 and September 1999. In the 15 minutes preceding shock, an anger level ≥3 preceded 15% of events compared with 3% of control periods (
P
<0.04; odds ratio, 1.83; 95% confidence intervals, 1.04 to 3.16) Other mood states (anxiety, worry, sadness, happiness, challenge, feeling in control, or interest) did not differ. Patients were more physically active preceding shock than in control periods. Anger and physical activity were independently associated with the preshock period.

Conclusions—

Anger and physical activity can trigger ventricular arrhythmias in patients with ICDs. Future investigations of therapies aimed at blocking a response to these stressors may decrease ventricular arrhythmias and shocks in these patients.
7-Hexanoyltaxol–Eluting Stent for Prevention of Neointimal Growth
Authors: Kataoka Toru , Grube Eberhard , Honda Yasuhiro , Morino Yoshihiro , Hur Seung-Ho , Bonneau Heidi N. , Colombo Antonio , Di Mario Carlo , Guagliumi Giulio , Hauptmann Karl E. , Pitney Mark R. , Lansky Alexandra J. , Stertzer Simon H. , Yock Paul G. , Fitzgerald Peter J.
Published: September 2002

Background—

Inhibition of neointimal tissue growth has been demonstrated in preliminary human feasibility studies with a stent-based polymer sleeve delivering 7-hexanoyltaxol. The Study to COmpare REstenosis rate between QueST and QuaDS-QP2 (SCORE) trial is a human, randomized, multicenter trial comparing 7-hexanoyltaxol (QP2)-eluting stents (qDES) with bare metal stents (BMS) in the treatment of de novo coronary lesions. The purpose of this substudy was to evaluate the acute expansion property and long-term neointimal responses of qDES compared with BMS as assessed by intravascular ultrasound (IVUS).

Methods and Results—

A total of 122 (qDES 66, BMS 56) patients were enrolled into the IVUS substudy. All IVUS images (immediately after the procedure and at 6-month follow-up) were analyzed at an independent core laboratory in a blind manner. At baseline, qDES achieved stent expansion similar to BMS. At follow-up, qDES showed reduced neointimal growth by 70% at the tightest cross section and by 68% over the stented segment (
P
<0.0001 for both), resulting in a significantly larger lumen in qDES than in BMS. Unlike intracoronary brachytherapy, there was no evidence of negative edge effects, unhealed dissections, or late stent-vessel wall malapposition over the stented and adjacent references segments in either group.

Conclusions—

Detailed IVUS analysis revealed that qDES had comparable acute mechanical and superior long-term biological effects to BMS. Although the long-term benefits and limitations of this technology require further investigation, the reduction in neointimal thickenings demonstrated that local delivery of 7-hexanoyltaxol through polymer sleeves augments conventional mechanical treatment of atherosclerotic disease.
Ventricular Rate Control by Selective Vagal Stimulation Is Superior to Rhythm Regularization by Atrioventricular Nodal Ablation and Pacing During Atrial Fibrillation
Authors: Zhuang Shaowei , Zhang Youhua , Mowrey Kent A. , Li Jianbo , Tabata Tomotsugu , Wallick Don W. , Popović Zoran B. , Grimm Richard A. , Natale Andrea , Mazgalev Todor N.
Published: September 2002

Background—

Selective atrioventricular nodal (AVN) vagal stimulation (AVN-VS) has emerged as a novel strategy for ventricular rate (VR) control in atrial fibrillation (AF). Although AVN-VS preserves the physiological ventricular activation sequence, the resulting rate is slow but irregular. In contrast, AVN ablation with pacemaker implantation produces retrograde activation (starting at the apex), with regular ventricular rhythm. We tested the hypothesis that, at comparable levels of VR slowing, AVN-VS provides hemodynamic benefits similar to those of ablation with pacemaker implantation.

Methods and Results—

AVN-VS was delivered to the epicardial fat pad that projects parasympathetic nerve fibers to the AVN in 12 dogs during AF. A computer-controlled algorithm adjusted AVN-VS beat by beat to achieve a mean ventricular RR interval of 75%, 100%, 125%, or 150% of spontaneous sinus cycle length. The AVN was then ablated, and the right ventricular (RV) apex was paced either irregularly (i-RVP) using the RR intervals collected during AVN-VS or regularly (r-RVP) at the corresponding mean RR. The results indicated that all 3 strategies improved hemodynamics compared with AF. However, AVN-VS resulted in significantly better responses than either r-RVP or i-RVP. i-RVP resulted in worse hemodynamic responses than r-RVP. The differences among these modes became less significant when mean VR was slowed to 150% of sinus cycle length.

Conclusions—

AVN-VS can produce graded slowing of the VR during AF without destroying the AVN. It was hemodynamically superior to AVN ablation with either r-RVP or i-RVP, indicating that the benefits of preserving the physiological antegrade ventricular activation sequence outweigh the detrimental effect of irregularity.
Effectiveness of Coronary Artery Bypass Grafting With or Without Cardiopulmonary Bypass in Overweight Patients
Authors: Ascione Raimondo , Reeves Barnaby C. , Rees Karen , Angelini Gianni D.
Published: September 2002

Background—

Off-pump coronary artery bypass surgery has been demonstrated to reduce morbidity in elective patients. However, high-risk patients might benefit the most from this surgical procedure. Our goal was to investigate the effectiveness of on-pump and off-pump coronary artery bypass surgery on early clinical outcome in a consecutive series of overweight patients.

Methods and Results—

From April 1996 to April 2001, data on 4321 patients undergoing coronary surgery (mortality 1.4%) were prospectively entered into the Patient Analysis and Tracking System. Data were extracted for all patients with a body mass index ≥25 kg/m
2
. A risk-adjusted analysis was performed to assess the effect of surgical technique in the whole overweight cohort. 2844 patients were identified (2261 male, median age 63, interquartile range 56 to 68). Patients undergoing on-pump surgery (2170, 76.3%) were less likely than those undergoing off-pump surgery to have hypercholesterolemia or left main stem disease and were, on average, less obese. However, they were more likely to have unstable angina and to have had a previous myocardial infarction, and they had more extensive coronary disease and received more grafts (all
P
<0.05). Unadjusted analyses, taking account only of consultant team, showed significant benefits of off-pump surgery in terms of hospital deaths, arrhythmias, inotropic use, use of intra-aortic balloon pump, blood loss, transfusion requirement, postoperative hemoglobin, chest infections, neurological complications, intensive care unit and hospital stay (all
P
<0.05). After adjustment for confounding prognostic factors, the benefits of off-pump surgery were still significant for death in hospital, transfusion requirement, postoperative hemoglobin, neurological complications, intensive care unit and hospital stay (ORs 0.35 to 0.79,
P
<0.05).

Conclusions—

These results suggest that off-pump surgery is safe and effective and is associated with a reduced in-hospital mortality and morbidity in overweight patients when compared with conventional coronary surgery with cardiopulmonary bypass and cardioplegic arrest.
Different Effects of Oral Conjugated Equine Estrogen and Transdermal Estrogen Replacement Therapy on Size and Oxidative Susceptibility of Low-Density Lipoprotein Particles in Postmenopausal Women
Authors: Wakatsuki Akihiko , Okatani Yuji , Ikenoue Nobuo , Fukaya Takao
Published: September 2002

Background—

Postmenopausal estrogen replacement therapy (ERT) has an antioxidant effect that opposes the oxidation of LDL particles. Oral ERT-induced increases in plasma triglyceride, however, decrease LDL particle size, which may counteract this antioxidant effect. Because transdermal ERT decreases plasma triglyceride, it may not decrease LDL particle size and may preserve estrogen’s antioxidant effect. The present study investigates whether transdermal ERT can eliminate the adverse effects of oral ERT on the size and oxidative susceptibility of LDL in postmenopausal women.

Methods and Results—

Postmenopausal women received no treatment (n=12) or were treated with either 0.625 mg oral conjugated equine estrogen daily (n=16) or with transdermal estradiol (50 μg/d, n=16) for 3 months. Plasma lipids and the diameter of LDL particles were determined. Susceptibility of LDL to oxidation was analyzed by incubation with CuSO
4
and subsequent measurement of thiobarbituric acid reactive substance (TBARS) concentrations. Oral ERT significantly increased plasma triglyceride and decreased LDL diameter but did not affect LDL-derived TBARS concentrations. In contrast, transdermal ERT significantly decreased the concentrations of plasma triglyceride and LDL-derived TBARS and significantly increased LDL diameter. Estrogen-induced changes in LDL diameter correlated negatively with changes in plasma triglyceride (
r
=−0.51,
P
<0.001) and LDL-derived TBARS (
r
=−0.50,
P
<0.001).

Conclusions—

Because transdermal, but not oral ERT, decreases plasma triglyceride and produces larger LDL particles that are resistant to oxidation, the antioxidant effect of estrogen can be preserved.
A robust model-based control for uncertain systems
Authors: Hamamci S. E. , Ucar A.
Published: September 2002

A new robust control strategy coefficient diagram method (CDM), which is an algebraic approach applied to a polynomial loop in the parameter space, is studied in this paper. Here, a model-based CDM is developed and proposed for uncertain systems. A special diagram called a coefficient diagram, which is used as a vehicle to carry the necessary information and as the criteria of good performance, is designed and modified accordingly. The performance of this novel controller is illustrated through several examples, and numerical results are provided.
Functional communication skills of children with speech difficulties: Performance on Bishop’s Children’s Communication Checklist
Authors: Nathan Liz
Published: September 2002

This paper examines the functional communication skills of a group of children with speech difficulties. Using the Children’s Communication Checklist (CCC) (Bishop, 1998), the effects of a significant speech difficulty on wider social communication were measured and compared to a control group. It was found that teachers and speech and language therapists rated children with speech difficulties less highly than controls on a range of communication skills. In addition to expected perceived differences between the groups on speech and syntax subscales, children with speech difficulties were rated significantly less highly on aspects of their social communication, including the subscales of communicative coherence and use of conversational context.