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Biomedical subjects

K W Lyles

Publications and source records attributed to K W Lyles.

At least 37 records · Page 2Linked to original sources
PubMed1995

Functional and mobility impairments associated with Paget's disease of bone.

OBJECTIVE: To determine if patients with Paget's disease of bone involving the tibia, femur, and/or acetabular portion of the ilium had more impairments in function and mobility than age- and sex-matched control subjects. PATIENTS AND METHODS: A case control study with Paget's disease patients selected from a center for bone disease at a tertiary medical center; control subjects were volunteers from the Duke University Aging Center subject registry. Demographic characteristics, physical examination and serum alkaline phosphatase levels were obtained. Radiographs of the pelvis and lower extremities were evaluated by a radiologist. All participants completed a Functional Status Questionnaire (FSQ). Mobility measures included mobility skills protocol, 10-foot walk time, 360-degree turn left (number of steps), and 6-minute walk distance. RESULTS: The 12 Paget's disease patients were no different in age (70.7 +/- 6.2 years) than the 12 control subjects (69.5 +/- 6.2 years). Serum alkaline phosphatase levels were elevated in Paget's patients (539 +/- 530 IU/L), and normal in control subjects (85 +/- 17 IU/L). In addition to Paget's disease, radiographs showed joint space loss in joints proximate to the diseased bone. On the FSQ scales Paget's disease patients had significantly lower scores in basic activities of daily living (P < .05), instrumental activities of daily living (P < .001), and social activity than control subjects (P < .05). There was no difference between the groups on scales measuring mental health and quality of social interaction. On mobility measurements, Paget's disease patients showed significant impairments when compared with control subjects: mobility skills protocol score (22.5 +/- 2.5 vs 25.6 +/- 0.7, P < .001); 10-foot walk (3.96 +/- 1.3 vs 2.55 +/- 0.5 seconds, P < .001); 360 degree turn left (8.0 +/- 1.0 vs 5.9 +/- 0.6 steps, P < .001); and 6-minute walk (342.0 +/- 108.5 vs 519.4 +/- 100 meters, P < .001). CONCLUSION: When compared with control subjects, patients who have Paget's disease of bone involving the tibia, femur, or acetabular portion of the ilium have clinically and statistically significant functional and mobility impairments compared to age- and gender-matched controls.

Activities of Daily Living↗
PubMed1994

Drug-induced bone disease.

Drugs can cause accelerated bone loss as well as disturbances in serum calcium levels. This article focuses on chemically induced bone diseases that commonly affect the elderly and result in either osteoporosis, osteomalacia, hypercalcemia or hypocalcemia. Also discussed are drugs that increase the risk of falls, putting those patients with osteoporosis at a greater risk for future.

Bone Diseases, Metabolic↗
PubMed1993

Association of osteoporotic vertebral compression fractures with impaired functional status.

PURPOSE: To determine if vertebral compression fractures in elderly women were associated with impairments in physical, functional, and psychosocial performance. SUBJECTS AND METHODS: Ten white women with confirmed vertebral compression fractures were age- and race-matched with 10 control subjects without fractures in a case-control design. All subjects invited to participate in this study were patients of the Geriatrics Division of the Department of Medicine at Duke University Medical Center. All study participants lived either in the community or in the independent-living sections of local retirement communities in and around Durham, NC. Subjects with fractures (mean age = 81.9 years, SD = 5.9 years) had two or more vertebral compression fractures in their medical records, whereas control subjects (mean age = 79.6 years, SD = 6.5 years) had no history of vertebral fractures. Spinal radiographs of all women confirmed group assignment. Physical, functional, and psychosocial performances were evaluated. Physical performance was assessed by measurements of maximal trunk extension torque and thoracic and lumbar spinal motion in the sagittal plane, functional reach, mobility skills, 10-ft timed walk, and 6-minute walk test. Thoracic and lumbar spinal configurations were also determined. Functional performance was assessed using the Functional Status Index. Psychosocial performance was assessed with the following scales: Hopkins Symptom Checklist 90 Revised, Rosenberg Self-Esteem Scale, West Haven-Yale Pain Inventory, Beck Depression Inventory, and single-item health-belief questions. RESULTS: Control subjects were not significantly different from patients with fractures in age, weight, number of current illnesses, number of prescribed medications, number of pain medications, ratings of lumbar spine degenerative disc disease, or lumbar spine facet joint arthritis. Activity levels and exercise participation were similar in both groups. Control subjects had no vertebral fractures, whereas fracture subjects had 4.2 +/- 2.6 fractures (range: 2 to 10). Thoracic kyphosis was increased and lumbar lordosis was reduced in fracture subjects. Fracture subjects had reduced maximal trunk extension torque, thoracic and lumbar spine sagittal plane motion, functional reach, mobility skills, and 6-minute walk test. The Functional Status Index showed reduced levels of functional performance in fracture subjects compared with controls with increased levels of assistance, pain with activity, and difficulty in activities. Psychosocial performance was limited in fracture subjects with increased psychiatric symptoms, increased pain, and greater perception of problems caused by health. CONCLUSION: Vertebral compression fractures are associated with significant performance impairments in physical, functional, and psychosocial domains in older women.

Activities of Daily Living↗
PubMed1993

Salmon calcitonin reduces vertebral bone loss in glucocorticoid-treated beagles.

Glucocorticoids induce bone loss by increasing bone resorption and decreasing bone formation. In this study we have investigated the potential of salmon calcitonin to attenuate glucocorticoid-induced bone loss in a dog model. Male beagles were divided into three groups: 1) untreated controls, 2) prednisone-treated dogs (1 mg.kg-1.day-1 orally), and 3) prednisone-calcitonin-treated dogs (1.5 U.kg-1.day-1 calcitonin subcutaneously and 1 mg.kg-1.day-1 prednisone orally). Assessment of bone mass by dual energy X-ray absorptiometry demonstrated that bone density remained stable in controls throughout 48 wk. Prednisone-treated dogs lost 13.2% of their initial bone mass by 48 wk. Concomitant calcitonin treatment attenuated prednisone-induced bone loss to only 3.2% at 48 wk. Bone histomorphometry of the spine showed reduced trabecular bone volume in prednisone-treated dogs, whereas control and prednisone-calcitonin-treated animals maintained normal trabecular bone volume. Both prednisone- and prednisone-calcitonin-treated dogs acquired a defect in osteoblastic function as evidenced by a reduction in mean wall thickness and trabecular thickness. Thus calcitonin attenuates the early bone loss induced by glucocorticoids. However, calcitonin failed to prevent glucocorticoid-induced osteoblast dysfunction.

Absorptiometry, Photon↗
PubMed1991

Uremic tumoral calcinosis: preliminary observations suggesting an association with aberrant vitamin D homeostasis.

Periarticular tumoral calcification is a unique form of soft tissue calcification that occurs infrequently in patients with end-stage renal disease. The mechanism underlying such massive periarticular calcifications is unknown. The radiographic similarity between uremic tumoral calcifications and those found in hereditary tumoral calcinosis, a disorder of calcitriol and phosphorus homeostasis, caused us to examine whether abnormalities in vitamin D metabolism were associated with uremic calcinosis as well. We examined two uremic subjects with massive periarticular tumoral calcifications and found that they had inappropriately high serum calcitriol levels for the degree of renal function, hyperparathyroidism, and hyperphosphatemia. The source of calcitriol could not be identified in one subject, but likely was derived from granulomatous tissue in the other. In the subject with marrow granulomas, we found that calcitonin administration further stimulated calcitriol production. Although epidemiological studies are needed to confirm this preliminary association between calcitriol and uremic tumoral calcinosis, our observations suggest that normal serum calcitriol levels in association with hyperphosphatemia may be a contributing factor in the development of this rare disorder.

Adult↗
PubMed1991

The metabolic effects of calcium supplementation in the elderly.

Because the value of calcium supplementation in age-related bone loss is controversial, we conducted a study to examine the effects of six months of calcium supplementation on parathyroid hormone (PTH) and other indices of bone metabolism. Calcium carbonate (1.2 grams elemental calcium/day) or placebo was administered for 6 months to a group of 42 healthy, ambulatory men and women with a mean age of 71. Fasting blood samples and 2-hour urine collections were performed at baseline and at 1 and 6 months. The decline in serum PTH levels from baseline in the calcium-supplemented group was significant in comparison with the placebo group changes (for the calcium group: 40.9 pg/mL at baseline to 34.0 pg/mL at 1 month and 33.2 at 6 months). This drop in PTH was associated with a decline in 1,25 OH-Vitamin D levels from a mean of 38.3 pg/mL to 30.4 pg/mL at 1 month and 31.9 at 6 months. During calcium supplementation, no changes were observed in serum bone Gla protein values. A decline in urinary hydroxyproline excretion was observed at 6 months, but this did not reach significant levels. The present study demonstrates suppression of PTH levels with calcium supplementation, an effect which lasts at least 6 months. This change was accompanied by a decrease in serum 1,25 OH-Vitamin D. The lack of significant changes in either serum bone gla protein or urine hydroxyproline excretion fails to support any significant change in bone turnover occurring with this decrease in PTH.

Administration, Oral↗
PubMed1991

Effects of short-term administration of glucocorticoids on bone metabolism in healthy elderly men.

OBJECTIVE: To determine the effects of short-term glucocorticoid administration in healthy elderly men on bone GLA protein (BGP) levels, as well as levels of calcium, phosphorus, immunoreactive parathyroid hormone (PTH), and alkaline phosphatase. DESIGN: Subjects served as own control before and after prednisone treatment. SETTING: Male subjects were recruited by telephone from the Duke University Aging Center Volunteer Registry and the Department of Veterans Affairs Medical Center Gerofit Program (a supervised exercise program). PARTICIPANTS: Healthy males age greater than 60 years with no history of diabetes mellitus, glucose intolerance, or prior glucocorticoid use. Subjects could not be taking diuretic agents and could not have osteoporosis. The seven subjects mean age +/- std dev was 68.6 +/- 5.3 years. INTERVENTIONS: Prednisone 40 mg orally for 5 days. Fasting serum was obtained at baseline, on days 7 through 11, 13, 15, and 17. Assays of BGP, calcium, phosphorus, PTH, and alkaline phosphatase were performed. MAIN OUTCOME MEASURES: Changes in serum BGP levels was the primary outcome measure. Changes in serum calcium, phosphorus, PTH, and alkaline phosphatase levels were secondary outcome measures. RESULTS: Treatment caused reduction in BGP levels within 24 hours of first dose of prednisone, with levels dropping an average of 78% during the 5 days of treatment (P = 0.004). Within 24 hours of stopping treatment, BGP was no different from baseline. Other variables did not change with treatment. CONCLUSION: Glucocorticoid treatment suppresses BGP production in healthy elderly men in the same fashion as it does in younger healthy men.

Administration, Oral↗
PubMed1991

Osteoporosis in late life: does health locus of control affect psychosocial adaptation?

Osteoporosis, a metabolic bone disease most prevalent in older adults, is a major public health problem. Although management of osteoporosis through diet, exercise, and medication has improved, little is known about the psychosocial consequences of this disabling disease. In an attempt to identify patient characteristics that would provide physicians with insight into appropriate management styles for older osteoporotics, we assessed 103 patients with osteoporosis for their health locus of control (HLOC) orientation. We examined the relationship between HLOC and patient outcomes after participation in the Duke University Preventive and Therapeutic Program for Osteoporosis (DUPATPO) to determine whether HLOC was associated with functioning after program participation. More specifically, we asked whether internal or external HLOC was associated with decreases in depression, psychiatric symptoms, and stress symptoms, or with increases in self-esteem, exercise, and disease knowledge. We have shown in our earlier work (Gold et al, J Am Geriatr Soc 1989; 37:417) that program participation is associated with improved functioning in older adults. We now asked whether knowledge of a patient's HLOC would help predict these improvements. A comparison group (ie, older osteoporotics who did not participate in DUPATPO) was also assessed for HLOC to examine the possible association between HLOC and health behaviors regardless of the DUPATPO intervention. Our findings indicate that HLOC provided little useful information regarding patient outcomes. Although improvements were seen in the mental health of program participants, no association between these improvements and HLOC could be found.

Adaptation, Psychological↗
PubMed1991

Dental lesions in tumoral calcinosis.

Tumoral calcinosis (TC) is a rare inherited autosomal dominant metabolic disease manifested by elevated serum phosphorus and 1,25 dihydroxyvitamin D levels and periarticular cystic and solid tumorous calcifications. The dental findings in a large family have been critical in determining the genetic transmission of the condition. Radiographically the teeth have short bulbous roots, pulp stones and partial obliteration of the pulp cavity. Histologically, coronal dentin and a variable amount of radicular dentin appears to be deposited regularly. At nonspecific points the developing radicular dentin appears to encounter a mass of calcified material and proceed to grow around it. This mass has a unique histologic pattern with ovoid spaces surrounded by amorphous calcification. At levels of further root development the radicular dentin has an irregular bending tubule arrangement. The dental lesion of TC appears to be different from that of radicular dentin dysplasia in histologic structure and in the method of initiation of the dentin defect. These data suggest that the specific dental lesion is a new phenotypic marker for TC.

Adolescent↗
PubMed1990

Glucocorticoid-induced osteoporosis: mechanisms for bone loss; evaluation of strategies for prevention.

Osteoporosis is a common complication of chronic glucocorticoid therapy, especially in older patients who already are at risk of having a reduced bone mass. Glucocorticoids cause bone loss by altering the bone remodeling sequence: bone resorption by osteoclasts is increased, and bone formation by osteoblasts is decreased. Serum levels of osteocalcin, a protein made by osteoblasts, are decreased with glucocorticoid therapy, further evidence of decreased osteoblast function. Glucocorticoids decrease calcium absorption by the gastrointestinal tract and increase renal calcium excretion. Several recent studies suggest that low-dose glucocorticoid therapy is not associated with bone loss. Calcium supplementation with vitamin D is recommended. Several short-term studies have shown prevention of glucocorticoid-induced bone loss with bisphosphonates, calcitonin, and progesterone. Long-term clinical trials should be undertaken to determine strategies to prevent this type of osteoporosis.

Aged↗
PubMed1990

Calcium supplementation lowers serum parathyroid hormone levels in elderly subjects.

To determine the effect of calcium supplementation on parathyroid hormone levels (PTH) in a group of elderly subjects at risk for developing Type II (senile) osteoporosis, 40 healthy volunteers participated in a randomized double-blind crossover study. Calcium carbonate or placebo was administered for 4 weeks, followed by a 4-week administration of the alternative intervention. Fasting blood samples and 24-hour urine collections were obtained at baseline, and at the end of each intervention period. Calcium supplementation (1000 mg/day) decreased serum PTH levels from a mean of 50.1 +/- 3.0 pg/ml to 41.9 +/- 2.4 pg/ml (p less than .001). Additionally, urine calcium excretion significantly increased during calcium administration (from 3.64 mmol/mmol creatinine at baseline to 4.28 mmol/mmol creatinine), but creatinine clearances and serum calcium levels remained unchanged. Type II osteoporosis has been associated with age-related increases in PTH levels. We have demonstrated the ability of increased calcium intake to decrease these levels, which may have implications for the management of a subset of patients with involutional osteoporosis.

Aging↗
PubMed1990

Imaging of tumoral calcinosis: new observations.

Five patients with tumoral calcinosis were evaluated with radiography, bone scintigraphy, computed tomography (CT), and magnetic resonance (MR) imaging. The arthropathy of calcium pyrophosphate dihydrate deposition disease was seen in two of the patients and pseudoxanthoma elasticum-like syndrome in three. Identification of calcific particular masses on radiographs is characteristic of tumoral calcinosis. Marrow lesions could be identified as patchy areas of calcification (calcific myelitis) in long bones and the calvarium. Bone scintigraphy appears to be the best modality for detection of the masses and marrow lesions and for monitoring therapy. At CT the masses demonstrated a varied appearance, from small and solid to large and cystic. The marrow abnormality appears as an area of increased attenuation and spotty calcification that in the skull may be associated with dural and vascular calcifications. MR imaging of the particular masses was remarkable in that the masses displayed high signal intensity on T2-weighted images despite a large calcific component. Marrow lesions also showed increased signal intensity on T2-weighted images. When calcified particular masses are present the diagnosis is rarely in question. The diagnosis may be overlooked, however, when calcific myelitis is the only manifestation.

Adult↗
PubMed1989

Geriatrics.

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Age Factors↗
PubMed1989

Treatment of osteoporosis. The psychological impact of a medical education program on older patients.

Participants in a therapeutic program for osteoporosis were studied to determine if program participation improved psychological outcomes. The 4-day program included intensive education about the disease and its prognosis, physical therapy education, nutritional counseling, and medical evaluation and treatment. All therapeutic patients enrolled in the program over a one-year period (N = 38) were interviewed individually pre- and post-participation. Knowledge of osteoporosis, level of social support, coping styles, and perceptions of the impact of pain and chronicity were assessed. Patients reported improved future outlook despite continued concern about pain and chronicity. Mention of depression was reduced, and knowledge of osteoporosis increased significantly. In addition, there were meaningful changes in patients' understanding of disease management. These included knowing when to make specific changes and avoid harmful actions. The findings suggest that an educational program can have a positive impact on patients' coping. Educational efforts may be an important component in the management of chronic disease.

Adaptation, Psychological↗
PubMed1988

Correlations of serum concentrations of 1,25-dihydroxyvitamin D, phosphorus, and parathyroid hormone in tumoral calcinosis.

The inherited metabolic disorder tumoral calcinosis is characterized by elevated serum phosphorus and 1,25-dihydroxyvitamin D [1,25-(OH)2D] levels and paraarticular calcific tumors. The pathogenesis of this disease is obscure, but an elevated renal phosphate reabsorption threshold and increased production of 1,25-(OH)2D are postulated as defects. We studied nine affected patients and found that both serum phosphorus and renal phosphate reabsorption threshold (TmP/GFR) were positively correlated with serum 1,25-(OH)2D levels. Since tumoral calcinosis is a disorder with abnormal renal phosphate transport, we compared the TmP/GFR and serum 1,25-(OH)2D levels to values obtained in patients with two other diseases with renal phosphate transport defects: oncogenic osteomalacia and X-linked hypophosphatemic rickets. We found a significant correlation between TmP/GFR and 1,25-(OH)2D levels in all three diseases, suggesting that in these diseases 1,25-(OH)2D production is regulated in some manner by phosphate transport. Furthermore, previous work indicated that in tumoral calcinosis broad variation exists in serum phosphorus levels. In our patients a negative correlation was found between the serum PTH concentrations and both serum phosphorus levels and TmP/GFR values, respectively. We postulate that although the basic defect in tumoral calcinosis most likely resides in the proximal renal tubular cell, the variation in serum phosphorus levels and possibly disease expression is modulated in part by PTH.

Absorption↗
PubMed1987

Skeletal disorders in malignant disease.

When the elderly are afflicted by malignancy, chances are good that at some point in the course of their illness the skeleton will be involved. Bone metastases, hypercalcemia, and other paraneoplastic syndromes are commonly encountered and require definitive diagnosis and management. In general, the therapy for the elderly patient with these disorders is the same as that for younger individuals. The diagnostic and therapeutic approach must often be tempered, however, by coexistent chronic disease, which may also affect the skeleton.

Aged↗