bluuebunny/crossref_metadata_2025_split huggingface dataset:
Severe Cortical and Trabecular Osteopenia in Secondary Hyperparathyroidism
Authors: Brancaccio Diego , Di Leo Claudio , Bestetti Alberto , Carpani Paola , Tagliabue Luca , Cozzolino Mario , Galassi Andrea , Luigi Tarolo Gian , Gallieni Maurizio 
Published: May 2003

Background:  Peripheral quantitative computed tomography (pQCT) provides real volumetric bone density values, not only of the total, but also of trabecular and cortical bone, separately. In addition, it provides data on bone geometry that can be related to the risk of fracture.Methods:  Total, cortical, and trabecular volumetric bone mineral densities (BMD), as well as the main geometric parameters (cross‐sectional area, cortical area, trabecular area, and cortical thickness) were assessed by pQCT at the distal radius in 24 hemodialysis patients affected by severe secondary hyperparathyroidism (PTH, mean ± SD: 1444 ± 695 pg/mL). The strength‐strain index (SSI), a biomechanical parameter describing bone fragility, was also determined.Results:  Compared with a control group of 64 healthy age‐matched subjects, volumetric BMD (mg/cm3) was significantly reduced in all patients (total BMD: 243 ± 87 vs. 405 ± 138, cortical BMD: 605 ± 218 vs. 856 ± 204, trabecular BMD: 95 ± 51 vs. 182 ± 75). Cortical area and cortical thickness showed significant modifications, while cross‐sectional area did not. SSI was significantly reduced (547 ± 125 vs. 927 ± 306 mm3). PTH levels showed a significant inverse correlation with cortical BMD (r = −0.56), cortical thickness (r = −0.46), cortical area (r = −0.61), and SSI (r = −0.54). Quantitative analysis of bone demonstrated cortical porosity.Conclusions:  In dialysis patients with severe secondary hyperparathyroidism, pQCT showed a significant cortical osteopenia, associated with geometric and mechanical bone impairment. Interestingly, we also found a comparable deficit of trabecular bone, which may be related to the very high PTH levels. Generalized cortical thinning, intracortical porosity and cortical‐endosteal resorption (“trabecularization” of the cortical bone) are major determinants of reduced bone strength, which may be quantitated by pQCT.
Efficacy of Tissue Plasminogen Activator for Thrombolysis in Central Venous Dialysis Catheters
Authors: O'Mara Neeta B. , Ali Samina , Bivens Kathleen , Sherman Richard A. , Kapoian Toros 
Published: May 2003

Background:  Low blood flow is a frequent complication of central‐vein (CV) dialysis catheters. Since thrombotic occlusion accounts for many cases of reduced blood flow, it is common practice to administer empiric thrombolytic therapy in an attempt to restore catheter patency and improve function.Methods:  We prepared tissue plasminogen activator (tPA) from 50 mg lyophilized powder, which was diluted (1 mg/mL) in sterile water for injection. A volume of 1 mL was frozen in 3 cc polystyrene syringes at −20 °C and thawed at room temperature when needed. tPA was then administered into the arterial and venous ports of the central venous catheter in a volume equal to the manufacturer's stated luminal volume and was allowed to dwell for 30 minutes.Results:  tPA was administered 62 times in 25 patients with 30 catheters (11 Tesio, 17 PermCath, 2 Shiley) for treatment of low blood flow (pump speed < 250 mL/min). Complete restoration of patency was achieved in 23 episodes (mean blood flow pre‐tPA 130 mL/min; post‐tPA 320 mL/min); partial restoration of patency was achieved in 20 episodes (mean blood flow pre‐tPA 69 mL/min; post‐tPA 233 mL/min). tPA was just as likely to be effective in patients with complete catheter occlusion (i.e., no blood flow) as it was when some initial blood flow was present. Nineteen episodes failed to respond to tPA. These episodes occurred in 13 catheters, 12 of which ultimately underwent radiologic evaluation; an extraluminal cause for low blood flow was found in all 12 catheters (6 malpositioned, 6 fibrin sheaths).Conclusions:  tPA at a dose of 1 mg/mL is effective for restoring patency in CV dialysis catheters. Failure to respond to tPA strongly suggests an extraluminal cause of catheter malfunction.
Extracellular Volume Changes and Blood Pressure Levels in Hemodialysis Patients
Authors: Katzarski Krassimir S. , Divino Filho José C. , Bergström Jonas 
Published: May 2003

Background:  Despite the use of highly efficient antihypertensive drugs (AHD), blood pressure (BP) is poorly controlled in the vast majority of hemodialysis (HD) patients. Many of them show no reduction in nocturnal BP, a finding that is associated with left ventricular hypertrophy. The aim of the study was to investigate the effect of the removal of a fluid overload on BP by monitoring the ambulatory BP during 48 hours in 16 hypertensive HD patients treated with AHD. Our aim was to obtain a gradual reduction in post‐HD body weight (BW) over a period of 3 to 4 months.Methods:  During a period of 3–4 months, the postdialysis BW was reduced as the minimal tolerable BW was gradually achieved by slightly increasing the ultrafiltration volume. The Na concentration in the dialysate was reduced from 143–141 mmol/L to 139–138 mmol/L. Extracellular volume (ECV) was measured with a multiple‐frequency bioimpedance analyzer (Xitron 4000B, Xitron Technologies Inc., San Diego, CA, USA). Based on the change in ECV, the patients were subdivided into two groups: group 1 with a reduction in ECV (n = 10), and group 2 with no reduction (n = 6). At the start of the study, BW, BP, and AHD in group 1 and group 2 were virtually identical.Results:  Group 1 showed a significant reduction during the entire 48‐hour period in systolic (156 ± 16 mmHg vs. 140 ± 14 mmHg, P = 0.030) and diastolic BP (97 ± 12 mmHg vs. 87 ± 9 mmHg, P = 0.026) as well as in mean arterial pressure (MAP, 117 ± 13 vs. 105 ± 10 mmHg, P = 0.027). This reduction was more marked during the night (systolic BP 156 ± 15 mmHg vs. 138 ± 14 mmHg, P = 0.007; diastolic BP 97 ± 12 mmHg vs. 85 ± 9 mmHg, P = 0.009) than during the day (157 ± 18 mmHg vs. 142 ± 15 mmHg, P = 0.067; diastolic BP 97 ± 13 mmHg vs. 90 ± 9 mmHg, P = 0.126). A significant reduction in systolic load also occurred during the entire 48‐hour period (76 ± 24% vs. 46 ± 28%, P = 0.043) as well as in night systolic load (75 ± 21% vs. 41 ± 30%, P = 0.015) and night diastolic load (67 ± 32% vs. 39 ± 31%, P = 0.030). AHD were stopped in eight and reduced in two patients. There were no significant reductions in BP and AHD in group 2.Conclusions:  The removal of excess fluid is necessary for adequate BP control and especially for the reduction in elevated BP during the night.
Vascular Access in the Hemodialysis Patient – Personal Experience and Review of the Literature
Authors: Konner Klaus 
Published: May 2003

There is consensus that arteriovenous (AV) fistulae represent the best choice for initial vascular access in patients suffering from chronic renal insufficiency (CRI) or end‐stage renal disease (ESRD) approaching the need of initiating hemodialysis therapy.However, this is a challenging task in the rapidly growing population of diabetic, aged, and hypertensive patients. The preexisting damage of the vascular anatomy and the high cardiovascular comorbidity hinder construction of a well functioning arteriovenous fistula. Late referrals to the nephrologist delay access surgery and increase the use of temporary and cuffed tunneled catheters with all their potential risks.Nevertheless, various strategies and tools exist to overcome these problems. Early referral results in venous preservation and early selection of side, site, and type of initial vascular access. Ultrasound findings are essential components of preoperative investigations. Special attention should be paid to the quality of the arteries at each section along the forearm, the elbow region, and the upper arm. Dedicated, meticulous surgery is mandatory. Fistula monitoring and elective revision of the failing AV fistula will result in increasing longevity of the blood access, and will reduce morbidity and costs.
Fallacies of High‐Speed Hemodialysis
Authors: Twardowski Zbylut J. 
Published: May 2003

Chronic hemodialysis sessions, as developed in Seattle in the 1960s, were long procedures with minimal intra‐ and interdialytic symptoms. Financial and logistical pressures related to the overwhelming number of patients requiring hemodialysis created an incentive to shorten dialysis time to four, three, and even two hours per session in a thrice weekly schedule. This method spread rapidly, particularly in the United States, after the National Cooperative Dialysis Study suggested that time of dialysis is of minor importance as long as urea clearance multiplied by dialysis time and scaled to total body water (Kt/Vurea) equals 0.95–1.0. This number was later increased to 1.3, but the assumption remained unchanged that hemodialysis time is of minimal importance as long as it is compensated by increased urea clearance. Patients accepted short dialysis as a godsend, believing that it would not be detrimental to their well‐being and longevity.However, Kt/Vurea measures only removal of low molecular weight substances and does not consider removal of larger molecules. Besides, it does not correlate with the other important function of hemodialysis, namely ultrafiltration. Whereas patients with substantial residual renal function may tolerate short dialysis sessions, the patients with little or no urine output tolerate short dialyses poorly because the ultrafiltration rate at the same interdialytic weight gain is inversely proportional to dialysis time. Rapid ultrafiltration is associated with cramps, nausea, vomiting, headache, fatigue, hypotensive episodes during dialysis, and hangover after dialysis; patients remain fluid overloaded with subsequent poor blood pressure control, left ventricular hypertrophy, diastolic dysfunction, and high cardiovascular mortality.Short, high‐efficiency dialysis requires high blood flow, which increases demands on blood access. The classic wrist arteriovenous fistula, the access with the best longevity and lowest complication rates, provides “insufficient” blood flow and is replaced with an arteriovenous graft fistula or an intravenous catheter. Moreover, to achieve high blood flows, large diameter intravenous catheters are used; these fit veins “too tightly,” so predispose the patient to central‐vein thrombosis.Longer hemodialysis sessions (5–8 hrs, thrice weekly), as practiced in some centers, are associated with lower complication rates and better outcomes. Frequent dialyses (four or more sessions per week) provide better clinical results, but are associated with increased cost. It is my strong belief that a wide acceptance of longer, gentler dialysis sessions, even in a thrice weekly schedule, would improve overall hemodialysis results and decrease access complications, hospitalizations, and mortality, particularly in anuric patients.
Growth Hormone Administration and Exercise Effects on Muscle Fiber Type and Diameter in Moderately Frail Older People
Authors: Hennessey James V. , Chromiak Joseph A. , DellaVentura Shirley , Reinert Steven E. , Puhl Jacqueline , Kiel Douglas P. , Rosen Clifford J. , Vandenburgh Herman , MacLean David B. 
Published: May 2003

OBJECTIVE: Reduced muscle mass and strength are characteristic findings of growth hormone deficiency (GHD) and aging. We evaluated measures of muscle strength, muscle fiber type, and cross sectional area in response to treatment with recombinant human growth hormone (rhGH) with or without a structured resistance exercise program in frail older subjects.DESIGN: Placebo‐controlled, randomized, double blind trial.SETTING: Outpatient clinical research center at an urban university‐affiliated teaching hospital.PARTICIPANTS: Thirty‐one consenting older subjects (mean age 71.3 ± 4.5 years) recruited as a subset of a larger project evaluating rhGH and exercise in older people, who underwent 62 quadricep‐muscle biopsies.INTERVENTION: Random assignment to a 6‐month course of one of four protocols: rhGH administered subcutaneously daily at bedtime, rhGH and a structured resistance exercise program, structured resistance exercise with placebo injections, or placebo injections only.MEASUREMENTS: Muscle biopsy specimens were obtained from the vastus lateralis muscle. Isokinetic dynamometry strength tests were used to monitor individual progress and to adjust the weights used in the exercise program. Serum insulin‐like growth factor‐I (IGF‐I) was measured and body composition was measured using a Hologic QDR 1000W dual X‐ray densitometer.RESULTS: The administration of rhGH resulted in significant increase in circulating IGF‐I levels in the individuals receiving rhGH treatment. Muscle strength increased significantly in both the rhGH/exercise (+55.6%, P = .0004) as well as the exercise alone (+47.8%, P = .0005) groups. There was a significant increase in the proportion of type 2 fibers between baseline and six months in the combined rhGH treated subjects versus those not receiving rhGH (P = .027).CONCLUSIONS: Our results are encouraging in that they suggest an effect of growth hormone on a specific aging‐correlated deficit. IGF‐I was increased by administrating rhGH and muscle strength was increased by exercise. The administration of rhGH to frail older individuals in this study resulted in significant changes in the proportions of fiber types. Whether changes in fiber cross‐sectional area or absolute number occur with long‐term growth hormone administration requires further study.
A Randomized Trial of Exercise Programs Among Older Individuals Living in Two Long‐Term Care Facilities: The FallsFREE Program
Authors: Nowalk Mary Patricia , Prendergast John M. , Bayles Constance M. , D'Amico Frank J. , Colvin Gerald C. 
Published: May 2003

OBJECTIVE: To use two different exercise programs over a 2‐year period to reduce falls and their sequelae among residents of two long‐term care facilities.DESIGN: Randomized, controlled trial.SETTING: The study took place at two long‐term care facilities with services ranging from independent living to skilled nursing.PARTICIPANTS: One hundred and ten participants whose average age was 84 and who were capable of ambulating with or without assistive devices and could follow simple directions.INTERVENTION: Participants were randomized to one of two exercise groups (resistance/endurance plus basic enhanced programming or tai chi plus basic enhanced programming) or to a control group (basic enhanced programming only). Exercise classes were held three times per week throughout the study.MEASUREMENTS: Participants were evaluated for cognitive and physical functioning at baseline and 6, 12, and 24 months. Falls were determined from incident reports filed by the nursing staffs at the facilities.RESULTS: Time to first fall, time to death, number of days hospitalized, and incidence of falls did not differ among the treatment and control groups (P> .05). Among all participants, those who fell had significantly lower baseline Folstein Mini‐Mental State Examination and instrumental activities of daily living scores and experienced significantly greater declines in these measures over the 2‐year program.CONCLUSION: There were no significant differences in falls among the two exercise groups and the control group. Lack of treatment differences and low adherence rates suggest that residents of long‐term care facilities may require individualized exercise interventions that can be adapted to their changing needs.
Deriving a Risk‐Adjustment Model for Pressure Ulcer Development Using the Minimum Data Set
Authors: Berlowitz Dan R. , Brandeis Gary H. , Morris John N. , Ash Arlene S. , Anderson Jennifer J. , Kader Boris , Moskowitz Mark A. 
Published: May 2003

OBJECTIVE: To use the Minimum Data Set (MDS) to derive a risk‐adjustment model for pressure ulcer development that may be used in assessing the quality of nursing home care.DESIGN: Perspective observational study using MDS data from 1997.SETTING: A large, for‐profit, nursing home chain.PARTICIPANTS: Our unit of analysis was 39,649 observations made on 14,607 nursing home residents who were without a stage 2 or larger pressure ulcer on an index assessment.MEASUREMENTS: Pressure ulcer status was determined at an outcome assessment approximately 90 days after an index assessment. Potential predictors of pressure ulcer development were examined for bivariate associations, contributing to the development of a multivariate logistic regression model.RESULTS: A stage 2 or larger pressure ulcer developed in 2.3% of the observations. Seventeen resident characteristics were found to be associated with pressure ulcer development. These included dependence in mobility and transferring, diabetes mellitus, peripheral vascular disease, urinary incontinence, lower body mass index, and end‐stage disease. A risk‐adjustment model based on these characteristics was well calibrated and able to discriminate among residents with different levels of risk for ulcer development (model c‐statistic = 0.73).CONCLUSION: A clinically credible risk‐adjustment model with good performance properties can be developed using the MDS. This model may be useful in profiling nursing homes on their rate of pressure ulcer development.
Evaluation of a Risk‐Adjustment Model for Pressure Ulcer Development Using the Minimum Data Set
Authors: Berlowitz Dan R. , Brandeis Gary H. , Anderson Jennifer J. , Ash Arlene S. , Kader Boris , Morris John N. , Moskowitz Mark A. 
Published: May 2003

OBJECTIVE: To validate a previously derived risk‐adjustment model for pressure ulcer development in a separate sample of nursing home residents and to determine the extent to which use of this model affects judgments of nursing home performance.DESIGN: Retrospective observational study using Minimum Data Set (MDS) data from 1998.SETTING: A large, for‐profit, nursing home chain.PARTICIPANTS: Twenty‐nine thousand and forty observations were made on 13,457 nursing home residents who were without a pressure ulcer on an index assessment.MEASUREMENTS: We used logistic regression in our validation sample to calculate new coefficients for the 17 previously identified predictors of pressure ulcer development. Coefficients from this new sample were compared with those previously derived. Expected rates of pressure ulcer development were determined for 108 nursing homes. Unadjusted and risk‐adjusted rates of pressure ulcer development from these homes were also calculated and outlier identification using these two approaches was compared.RESULTS: Predictors of pressure ulcer development in the derivation sample generally showed similar effects in the validation sample. The model c‐statistic was also unchanged at 0.73, but it was not calibrated as well in the validation sample. On applying the model to the nursing homes, expected rates of ulcer development ranged from 1.1% to 3.2% (P < .001). The observed rates ranged from 0% to 12.1% (P < .001). There were 12 outliers using unadjusted rates and 15 using adjusted performance. Ten nursing homes were identified as outliers using both approaches.CONCLUSIONS: Our MDS risk‐adjustment model for pressure ulcer development performed well in this new sample. Nursing homes differ significantly in their expected rates of pressure ulcer development. Outlier identification also differs depending on whether unadjusted or risk‐adjusted performance is evaluated.
Serum and Urine Markers of Bone Metabolism During the Year After Hip Fracture
Authors: Yu‐Yahiro Janet A. , Michael Roger H. , Dubin Norman H. , Fox Kathleen M. , Sachs Myron , Hawkes William G. , Hebel J. Richard , Zimmerman Sheryl I. , Shapiro Jay , Magaziner Jay 
Published: May 2003

OBJECTIVE: As part of a larger study to describe indices of recovery during the year after hip fracture, the current prospective study investigated longitudinal changes in serum and urine markers of bone metabolism for the year after hip fracture and related them to bone mineral density (BMD).DESIGN: A representative subset of participants provided serum and urine samples and had bone density measured at 3, 10, 60, 180, and 365 days postfracture.SETTING: Two Baltimore hospitals.PARTICIPANTS: The subjects were 205 community‐dwelling, white women age 65 and older with fresh proximal femur fractures.MEASUREMENTS: Samples were assayed for specific bone‐related proteins and bone turnover markers, including serum osteocalcin (OC), procollagen type 1 carboxy‐terminal extension peptide (PICP), bone‐specific alkaline phosphatase (BAP), and urinary deoxypyridinoline (DPD) cross‐links. Selected hormonal regulators of bone metabolism, including parathyroid hormone (PTH), calcitonin (CT), 1,25‐dihydroxy vitamin D3 (1,25 (OH)2D), and estrone (E1) were measured from serum samples. Repeated measures analyses were used to evaluate postfracture changes in each of the markers.RESULTS: BAP, OC, and PICP were most active during the early postfracture period (3–60 days). BAP and OC remained elevated at 365 days compared with 3 days. DPD rose 48% from 3 days to 60 days, but this difference was not statistically significant. PTH and 1,25 (OH)2D increased steadily and significantly from 3 to 365 days. E1 was highest at baseline and decreased at each time point, whereas CT showed no significant changes. When subjects were stratified into high‐, medium‐, and low‐BMD groups based on their measurement at 3 days, both osteoclastic and osteoblastic markers in the low‐BMD group displayed exaggerated and different patterns over time compared with the other groups.CONCLUSION: Currently, the standard treatment of care for hip fractures still results in high morbidity and mortality and failure to regain prefracture quality of life. Gaining an understanding of bone cell activity in these patients after hip fracture, derived by measuring markers longitudinally during recovery, provides a baseline by which to measure the effectiveness of new interventions to improve recovery from hip fracture.