bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of repeated isometric contractions on muscle deoxygenation and pulmonary oxygen uptake kinetics in humans
Authors: Bringard Aurélien , Perrey Stéphane 
Published: July 2004

SummaryThe purpose of the present study was to compare simultaneously vastus lateralis (VL) deoxygenation and pulmonary O2 uptake (O2) kinetics during fatiguing knee extension exercise with minimal cardiac load. Eight healthy subjects realized an intermittent bilateral knee‐extension exercise (3‐s contraction/3‐s relaxation) at 40% of maximum voluntary contraction for 10 min. VL deoxygenation was recorded by near infrared spectroscopy at 2 Hz (NIRO‐300, Hamamatsu Photonics, Japan) and O2 was determined breath‐by‐breath (K4b2, Cosmed, Italy). After a time delay of 16 ± 5 s, deoxygenation kinetics at the onset of exercise followed an exponential time course at a significant faster rate than O2 (time constant of 5·4 ± 4·0 s vs. 31·6 ± 10·4 s, P<0·01) reflecting a mismatch between local O2 consumption and perfusion. Thereafter, a rise in O2 of 223 ± 123 ml min−1 (consistent with the mathematical model, 259 ± 126 ml min−1) was observed between minutes 2 and 10. During the same exercise time, changes in tissue oxygenation index decreased significantly and were individually correlated with the corresponding increased O2 (P<0·05), suggesting that the majority of the slow rise of O2 arose from the exercising limbs. Averaged heart rate increased from 67 ± 11 to 116 ± 20 beats min−1 during exercise. Knee extension exercise may be relevant to estimate the cardiopulmonary and deoxygenation of working skeletal muscle responses for assessment of exercise limiting factors in clinical settings or in the exercise physiology.
Brain glucose and lactate levels during ventilator‐induced hypo‐ and hypercapnia*
Authors: van Hulst R. A. , Lameris T. W. , Haitsma J. J. , Klein J. , Lachmann B. 
Published: July 2004

SummaryObjective:  Levels of glucose and lactate were measured in the brain by means of microdialysis in order to evaluate the effects of ventilator‐induced hypocapnia and hypercapnia on brain metabolism in healthy non‐brain‐traumatized animals.Design and setting:  Prospective animal study in a university laboratory.Subjects:  Eight adult Landrace/Yorkshire pigs.Interventions:  The microdialysis probe was inserted in the brain along with a multiparameter sensor and intracranial pressure (ICP) probe. The animals were ventilated in a pressure‐controlled mode according to the open lung concept with an inspired oxygen fraction of 0·4/1·0. Starting at normoventilation (PaCO2 ±40 mmHg) two steps of both hypercapnia (PCO2 ± 70 and 100 mmHg) and hypocapnia (PaCO2 ± 20 and 30 mmHg) were performed. Under these conditions, brain glucose and lactate levels as well as brain oxygen (PbrO2), brain carbon dioxide (PbrCO2), brain pH (brpH), brain temperature and ICP were measured.Results:  At hypercapnia (PaCO2 = 102·7 mmHg) there were no significant changes in brain glucose and lactate but there was a significant increase in PbrCO2, PbrO2 and ICP. In contrast, at hypocapnia (PCO2 = 19·8 mmHg) there was a significant increase in brain lactate and a significant decrease in both brain glucose and PbrCO2.Conclusions:  Hypocapnia decreases brain glucose and increases brain lactate concentration, indicating anaerobic metabolism, whereas hypercapnia has no influence on levels of brain glucose and brain lactate.
Developing an integrated paediatric low vision service*
Authors: Rudduck Gillian , Corcoran Helen , Davies Kay 
Published: July 2004

AbstractA survey of usage of low vision aids (LVAs) by 56 children with visual impairment, who were attending mainstream schools in Wirral, was undertaken. A total of 25% of children owned an LVA and 5% were using these on a regular basis. These low levels of ownership and usage led to the development of a low vision service involving the collaboration of education and health care. This paper describes the development of that service, its elements and implementation. The results from the new service show that of the 29 children issued with an LVA, 82.7% are using them on a regular basis. Having an integrated service is shown to significantly improve LVA usage in the group of children seen so far. The service results are discussed with suggestions for future service development.
Multihospital System Membership and Patient Treatments, Expenditures, and Outcomes
Authors: Madison Kristin 
Published: July 2004

Objective. To determine the relationship between hospital membership in systems and the treatments, expenditures, and outcomes of patients.Data Sources. The Medicare Provider Analysis and Review dataset, for data on Medicare patients admitted to general medical‐surgical hospitals between 1985 and 1998 with a diagnosis of acute myocardial infarction (AMI); the American Hospital Association Annual Survey, for data on hospitals.Study Design. A multivariate regression analysis. An observation is a fee‐for‐service Medicare AMI patient admitted to a study hospital. Dependent variables include patient transfers, catheterizations, angioplasties or bypass surgeries, 90‐day mortality, and Medicare expenditures. Independent variables include system participation, other admission hospital and patient traits, and hospital and year fixed effects. The five‐part system definition incorporates the size and location of the index admission hospital and the size and distance of its partners.Principal Findings. While the effects of multihospital system membership on patients are in general limited, patients initially admitted to small rural system hospitals that have big partners within 100 miles experience lower mortality rates than patients initially admitted to independent hospitals. Regression results show that to the extent system hospital patients experience differences in treatments and outcomes relative to patients of independent hospitals, these differences remain even after controlling for the admission hospital's capacity to provide cardiac services.Conclusions. Multihospital system participation may affect AMI patient treatment and outcomes through factors other than cardiac service offerings. Additional investigation into the nature of these factors is warranted.
Adoption of Liquid‐Based Cervical Cancer Screening Tests by Family Physicians and Gynecologists
Authors: Rappaport Karen M. , Forrest Christopher B. , Holtzman Neil A. 
Published: July 2004

Objective. To examine reasons for the adoption of liquid‐based cervical cancer screening tests.Data Sources/Study Setting. A mailed survey of 250 family physicians and 250 gynecologists in Maryland in 2000. Additional data were obtained from the AMA Master File of Physicians.Study Design. Key outcome variables in this cross‐sectional survey were early adoption of a liquid‐based test by the end of 1997 and overall adoption by the time of the survey. Adoption was viewed in terms of a supply and demand theoretical framework with marketing influencing physician and patient demand as well as supply by insurance companies and laboratories.Data Collection. Random samples of family physicians and gynecologists were selected from the AMA Master File of Physicians. The overall response rate was 61.9 percent.Principal Findings. By 2000, 96 percent of gynecologists and 75 percent of family physicians in Maryland were using liquid‐based cervical cancer screening tests, most commonly the ThinPrep® Pap Test™. Gynecologists were more likely than family physicians to have been early adopters (34 percent versus 5 percent, p<.01). Part of this variation in adoption was due to aggressive marketing to gynecologists, who were more likely than family physicians to receive information in the mail from the test manufacturer (89 percent versus 56 percent, p<.01) and to have been informed by the manufacturer that a patient had inquired about physicians' use of the test (22 percent versus 8 percent, p<.01).Conclusions. The rapid diffusion of liquid‐based cervical cancer screening tests occurred despite general agreement that the Pap smear has been one of the most successful cancer prevention interventions ever. Commercial marketing campaigns appear to contribute to the more rapid rate of diffusion of technology among specialists compared with generalists.
Development of the Patient Activation Measure (PAM): Conceptualizing and Measuring Activation in Patients and Consumers
Authors: Hibbard Judith H. , Stockard Jean , Mahoney Eldon R. , Tusler Martin 
Published: July 2004

Background. Controlling costs and achieving health care quality improvements require the participation of activated and informed consumers and patients.Objectives. We describe a process for conceptualizing and operationalizing what it means to be “activated” and delineate the process we used to develop a measure for assessing “activation,” and the psychometric properties of that measure.Methods. We used the convergence of the findings from a national expert consensus panel and patient focus groups to define the concept and identify the domains of activation. These domains were operationalized by constructing a large item pool. Items were pilot‐tested and initial psychometric analysis performed using Rasch methodology. The third stage refined and extended the measure. The fourth stage used a national probability sample to assess the measure's psychometric performance overall and within different subpopulations.Study Sample. Convenience samples of patients with and without chronic illness, and a national probability sample (N=1,515) are included at different stages in the research.Conclusions. The Patient Activation Measure is a valid, highly reliable, unidimensional, probabilistic Guttman‐like scale that reflects a developmental model of activation. Activation appears to involve four stages: (1) believing the patient role is important, (2) having the confidence and knowledge necessary to take action, (3) actually taking action to maintain and improve one's health, and (4) staying the course even under stress. The measure has good psychometric properties indicating that it can be used at the individual patient level to tailor intervention and assess changes.
A new Bayesian method to forecast and fine tune individual hemodialysis dose
Authors: Pfister M , Uehlinger D E , Hung A M , Schaedeli F , Sheiner L B 
Published: July 2004

AbstractBackground:  The most commonly used formulas for hemodialysis dose are based on single‐pool urea kinetics; i.e., they consider the body as a single compartment and use an ad hoc adjustment for postdialysis urea rebound. We present a new urea kinetic modeling approach, individualized Bayesian urea kinetic modeling (IBKM), which incorporates prior knowledge. This method uses measurements made during previous treatments to forecast a patient's postdialysis urea rebound and clearance and provides a choice of possible dialysis parameters to achieve a desired clearance goal.Methods:  We used data from 18 patients (a total of 38 hemodialysis sessions) to build the model. All patients had been on thrice‐weekly hemodialysis for at least 1 year before enrollment, and their dialysis prescription remained unchanged during the study period. Recorded variables included blood urea nitrogen (BUN) measurements and dialysis prescription parameters (dialyzer size, KoA, treatment time, blood and dialysis flow). The population distribution of urea kinetic parameters—derived from the 18 patients' data—and individual urea kinetic data (i.e., pre‐ and postdialysis BUN) are used in the IBKM method to make individual predictions.Results:  Estimates (mean±SE) of population urea kinetic parameters are generation rate 0.17±0.01 mmol/min, clearance between extracellular and intracellular compartments 646±60 mL/min, and total volume of distribution 31.5±1.5 L, of which the extracellular volume is 36±4%. The effective dialysis clearance is estimated to be 9.0±1.7%, less than the expected dialyzer clearance. IBKM predictions of postdialysis equilibrated BUN concentrations are accurate: a root mean squared error of 3.4% of the “postrebound” BUN concentration at 30 min, a value in the range of urea measurement error itself.Conclusions:  IBKM can estimate not only the urea kinetics of an actual hemodialysis, but it can also predict a patient's target hemodialysis dose for any desired, flexible hemodialysis treatment. The method should prove useful for bedside monitoring, forecasting, and fine tuning of hemodialysis dose.
Coronary and aortic calcifications in patients new to dialysis
Authors: Spiegel David M , Raggi Paolo , Mehta Ravindra , Lindberg Jill S , Chonchol Michel , Ehrlich James , James George , Chertow Glenn M , Block Geoffrey A 
Published: July 2004

AbstractBackground:  Vascular calcification has been associated with all cause and cardiovascular mortality in patients with end‐stage kidney disease (ESRD). Whether vascular calcification is present in persons with advanced chronic kidney disease starting dialysis or develops in patients on dialysis is unknown. The purpose of this study was to examine the prevalence of vascular and coronary calcification in patients new to hemodialysis.Methods:  A total of 129 subjects new to dialysis were evaluated using electron beam computed tomography. The primary outcome was the presence and extent of coronary artery, aortic, and valvular calcification.Results:  Forty‐three percent of subjects had no significant coronary artery calcification (total score ≤ 30) and 27% had no detectable aortic calcification. Thirty‐four percent had coronary artery scores that placed them above the 90th percentile for age and sex. Coronary artery calcification was significantly associated with a history of coronary artery disease and atherosclerotic vascular disease (ASVD) whereas aortic calcification was significantly associated with ASVD. Age (p < 0.0001), pulse pressure (p = 0.004), diabetes mellitus (p = 0.009), and a history of smoking (p = 0.026) were independently associated with the extent of coronary artery calcification. Age (p < 0.0001) and pulse pressure (p = 0.0003) were independently associated with the extent of aortic calcification.Conclusions:  A large fraction of patients new to hemodialysis had no evidence of coronary artery or aortic calcification. Coupled with the extensive vascular calcification reported by others in prevalent dialysis patients these findings suggest that dialysis‐specific factors contribute to calcific vascular disease in ESRD.
Prevention of hemodialysis‐related muscle cramps by intradialytic use of sequential compression devices: A report of four cases
Authors: Ahsan Muhammad , Gupta Mini , Omar Irfan , Frinak Stanley , Gendjar Suzette , Osman‐Malik Yayha , Yee Jerry 
Published: July 2004

AbstractBackground:  Hemodialysis (HD)‐related lower extremity (LE) muscle cramps are a common cause of morbidity in end‐stage renal disease patients on maintenance HD. Numerous pharmacologic and physical measures have been tried with variable success rates.Methods:  Sequential compression devices (SCD) improve venous return (VR) and are commonly used to prevent LE deep venous thrombosis in hospitals. We hypothesized that LE cramps are triggered by stagnant venous flow during HD and are preventable by improving VR. We prospectively studied four adult patients (mean age 61 ± 14 years) on thrice‐weekly HD who experienced two or more episodes of LE cramping weekly in the month before the study. SCD were applied before each HD on both legs and compressions were intermittently applied at 40 mmHg during treatment.Results:  All four patients reported complete resolution of cramping during the study period that lasted 1 month or 12 consecutive dialysis treatments.Conclusion:  Application of SCD to LE may prevent the generation of LE HD‐related cramping in a select group of patients. Larger, controlled studies are needed to establish the utility of this noninvasive alternative for the prevention of LE HD‐related cramps.
Rapid evaluation of risk of white particulate matter in blood components by a statewide survey of transfusion reactions
Authors: Iwamoto M. , Curns A.T. , Blake P.A. , Jernigan D.B. , Holman R.C. , Lance‐Parker S.E. , Chamberland M.E. , Kuehnert M.J. 
Published: July 2004

BACKGROUND:  In January 2003, white particulate matter (WPM) was detected in blood components. Because the composition and cause of WPM was not understood at that time, there was uncertainty about whether WPM could endanger patient safety. To investigate possible adverse patient events associated with WPM, transfusion reaction rates were examined.STUDY DESIGN AND METHODS:  A questionnaire was distributed to Georgia medical centers. Data collected included the number of components transfused and reported adverse reactions by component type from January 2002 through January 2003, and date, reaction type, and blood supplier for events in January 2003.RESULTS:  Of 124 transfusion services contacted, 108 (87%) responded. During the survey period, there were 1213 reported transfusion reactions and 528,412 units transfused, or 2.3 reactions per 1000 units transfused; for RBCs, 2.4 (range, 1.8‐3.1); plasma, 1.5 (range, 0.6‐3.5); and PLTs, 3.4 (2.1‐5.4) per 1000 units. Transfusion reaction rates by component for January 2003 did not differ significantly from the rate for January 2002 or for the calendar year. The 86 reported reactions that occurred in January 2003 were attributed to bacterial contamination (n = 2, 2.3%), other febrile nonhemolytic (n = 49, 57.0%), allergic (n = 14, 16.3%), and “other” reactions (n = 21, 24.4%); the proportions of reaction types did not differ significantly during the month.CONCLUSION:  No overall changes in reported adverse reaction rates occurred over the survey period or in the proportion of reaction types during January 2003 when WPM was detected. Statewide surveillance of transfusion reactions could be useful to evaluate potential threats to blood safety.
Different susceptibility of B19 virus and mice minute virus to low pH treatment
Authors: Boschetti Nicola , Niederhauser Isabel , Kempf Christoph , Stühler Albert , Löwer Johannes , Blümel Johannes 
Published: July 2004

BACKGROUND:  Parvoviridae are small nonenveloped viruses that are known to be highly resistant to physico‐chemical treatments. Because low pH is frequently applied to process intermediates or final products, the impact of such conditions on the human erythrovirus B19 (B19V) and the mouse parvovirus (mice minute virus, MMV) was assessed, which is often used as a model for B19V. Owing to the lack of a suitable cultivation and/or detection system for B19V no such data exist so far.STUDY DESIGN AND METHODS:  Virus inactivation was monitored by decrease of infectivity and loss of capsid integrity. Infectious B19V was quantified by dete‐ction of virus‐specific messenger RNA from Ku812Ep6 cells. To measure capsid integrity, endonucleases were added after exposure to low pH and the encapsidated (endonuclease‐protected) virus DNA was quantified by real‐time PCR.RESULTS:  B19V was inactivated greater than 5 log after 2 hours at pH 4, whereas MMV was resistant over 9 hours. Infectivity data strongly correlated with data obtained by the endonuclease assay. Capsid disintegra‐tion was observed in immunoglobulin G as well as in different albumin solutions. Temperature and pH showed concerted impact on B19V capsid disintegration.CONCLUSION:  Our data show that B19V is much more vulnerable toward low pH conditions than MMV. Together with the previously reported susceptibility of B19V toward wet heat conditions, low pH is the second treatment where erythrovirus B19V is less resistant than viruses from the parvovirus genus.
A new hybrid RHCE gene (CeNR) is responsible for expression of a novel antigen
Authors: Westhoff Connie M. , Storry Jill R. , Walker Phyllis , Lomas‐Francis Christine , Reid Marion E. 
Published: July 2004

BACKGROUND:  The red blood cells (RBCs) of a patient, known to have the probable DCW(e)/D‐‐ phenotype, typed as DW– and Rh32– but were unexpectedly agglutinated by an anti‐DW/Rh32 serum. The reactivity suggested that the RBCs carried a novel antigen and that the molecular background of this DCW(e)/D‐‐ phenotype might be different from those reported. The purpose of this study was to determine the molecular basis of the Rh phenotype. STUDY DESIGN AND METHODS: Samples were obtained for family studies. Standard hemagglutination methods were used. RH mRNA transcripts were isolated by reverse transcription‐polymerase chain reaction and sequenced.RESULTS:  Sequence analysis revealed that the probond had three different RH transcripts: a normal RHD and two different hybrid transcripts from the RHCE locus, a RHCE‐D hybrid with exon 1 from RHCE associated with the D‐‐ haplotype, and a new RHCE‐D hybrid. In this new hybrid, exons 1 to 5 are RHCe‐specific and exons 6 to 10 correspond to RHD. The CW antigen is also encoded by this hybrid gene. Family studies confirmed that the new RHCE‐D hybrid is linked in cis to conventional RHD.CONCLUSION:  A new RHCE‐D structure is associated with altered expression of C and e antigens in this family and the generation of a novel low‐prevalence antigen (CENR).
Capillary blood cell velocity in periulcerous regions of the lower leg measured by laser Doppler anemometry
Authors: Stücker Markus , Huntermann Christina , Bechara Falk Georges , Hoffmann Klaus , Altmeyer Peter 
Published: July 2004

Background: The capillary blood flow of the nailfold can be measured by means of modern non‐invasive techniques like the videocapillary microscope in vivo. To quantify the capillary blood cell velocity, apart from the nailfold capillaries, we used a new technique, the so‐called laser Doppler anemometry (LDA).Objective: The present study investigated how far laser Doppler fluxmetry (LDF), transcutaneous partial pressure of oxygen (tcpO2), and LDA are capable of quantifying differences of cutaneous microcirculation between patients with leg ulcera and a healthy control group. The effects of intravenous prostaglandin E1 and pentoxifylline were also investigated.Patients and methods: Ten patients with venous leg ulcers and 10 patients with mixed venous/arterial ulcers were investigated with LDF, tcpO2, and LDA before and after injection of prostaglandin E1 and pentoxifylline. We measured the resting capillary blood cell velocity (rCBV), the maximum hyperemia, and the time to peak capillary blood cell velocity (tpCBV) during hyperemia after 4 min of suprasystolic occlusion and compared them with the results of a contol group of 20 patients.Results: Laser Doppler flow was increased in all patients during resting period, whereas the tcpO2 was significantly decreased. LDF did not show an extension of tpCBV during reactive hyperemia after suprasystolic occlusion compared to the control group (73.6±31.1 vs. 164.1±52.5 s, P=0.003). TcpO2 revealed significantly dereased tpCBV in patients with venous and mixed venous/arterial ulcers (90.1±61.7 vs. 162.7±65.5 s, P≤0.0001). LDA showed no significant differences between patients and control group (P>0.8). After application of prostaglandin E1, LDA revealed a significant increase of erythrocyte velocity (0.5±0.18 to 0.74±0.28 mm/s [P=0,01]), whereas pentoxifylline had no significant effect. Capillary density increased significantly after application of prostaglandin E1 (5,1±2.7/mm2 to 8.9±3/mm2 [P=0.001]) and pentoxifylline (5.3± 1.8/mm2 to 8±2.1/mm2 [P=0.006]).Conclusion: The LDA is an important additional investigation tool for cutaneous microcirculation.