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R Hamdy

Publications and source records attributed to R Hamdy.

15 recordsLinked to original sources
PubMed2006

The prevalence of significant left-right differences in hip bone mineral density.

INTRODUCTION: We determined the prevalence of left-right differences in hip bone mineral density (BMD) by dual-energy x-ray absorptiometry (DXA) and the resultant consequence, namely: the frequency at which patients would be classified differently if lumbar spine and only one hip (rather than both hips) were measured. METHODS: This was a retrospective DXA scan reanalysis of 3012 white women >or=50 yrs who had scans of both hips using Hologic DXA systems. The difference between left and right hips was considered significant if it exceeded the least significant change (LSC) for any of three hip subregions (total hip, femoral neck, trochanter). The number of women with osteoporosis in both hips, the left hip only, or the right hip only was determined by lowest T-score from total hip, femoral neck, or trochanter. RESULTS: Despite high left-right correlations of subregion BMD, significant left-right differences in BMD were common: the difference exceeded the LSC for 47% of women at total hip, 31% at femoral neck, and 56% at trochanter. Left-right differences in BMD that exceeded the LSC affected the percent agreement of left-right hip classification: for all women irrespective of spine status, there was 77% classification (diagnostic) agreement in hip pairs in which the left-right hip BMD difference exceeded the LSC versus 87% agreement in which LSC was not exceeded (significant difference in proportions, P<0.0001). The greatest risk of different classification would occur in women with normal spines as the diagnosis might be determined by hip T-scores. Using L1-4 lumbar spine T-scores, 1229 women were normal at the spine. Twenty-four (2%) were osteoporotic at both hips. However, 12 women (1%) were osteoporotic only in the left hip (significantly different from zero, P<0.001) and 11 (1%) only in the right hip (P<0.001); of these 23 women, the difference in BMD between the osteoporotic hip and the contralateral hip exceeded the LSC in 16 (70% of those with osteoporosis in only one hip). Using L1-4 lumbar spine T-scores, 1159 women were osteopenic at the spine. Of these, 126 (11%) were osteoporotic at both hips, 54 (5%) only in the left hip (P<0.001), and 42 (4%) only in the right hip (P<0.001); of these 96 women, the difference in BMD between the osteoporotic hip and the contralateral hip exceeded the LSC in 56 (58% of those with osteoporosis in only one hip). CONCLUSIONS: A statistically significant number of women with osteoporosis are potentially classified differently when scanning only one hip as a result of the high prevalence of left-right differences in BMD. Although the percentages are low, the total number of women affected may be large. From a public health perspective, the practice of scanning both hips could potentially identify more women with osteoporosis and may help prevent future hip fractures.

Absorptiometry, Photon↗
PubMed2000

Temporal and spatial expression of bone morphogenetic protein-2, -4, and -7 during distraction osteogenesis in rabbits.

The Ilizarov method of limb lengthening makes use of the fact that osteogenesis is induced at an osteotomy site when distraction is applied. It is unknown at present how the mechanical forces created by distraction are translated into biological signals. Because bone morphogenetic proteins (BMPs) are potent inducers of osteogenesis in many experimental systems, they are obvious candidates for playing a role in this process. In this study, we investigated the temporal and spatial expression of BMP-2, -4, and -7 proteins during distraction osteogenesis using immunohistochemistry. An osteotomy was performed on the right tibiae of white New Zealand rabbits. After a delay of 7 days, distraction was started at a rate of 0.25 mm/12 h for 3 weeks, followed by a 3 week consolidation phase. Each week after osteotomy one rabbit was killed for immunohistochemical studies. Staining for BMP-2, -4, and -7 was evident before distraction was applied and was mainly localized to mesenchymal cells and osteoblastic cells in the periosteal region. After distraction was started, the typical fibrous interzone developed between the osteotomy fragments, where both intramembranous and endochondral ossification were noted. In this area, cells resembling fibroblasts and chondrocytes, but not mature osteoblasts, showed intense staining for all three BMPs. This high level of expression was maintained during the entire distraction phase and then gradually disappeared during the consolidation phase. These results are compatible with the hypothesis that BMPs play an important role in the signaling pathways that link the mechanical forces created by distraction to biological responses.

Animals↗
PubMed2000

Effects of locally applied transforming growth factor-beta1 on distraction osteogenesis in a rabbit limb-lengthening model.

In this study we tested the effect of locally applied transforming growth factor-beta1 (TGF-beta1) on distraction osteogenesis in rabbits. A total of 61 rabbits were studied. Seven days after tibial osteotomy, distraction was started at a rate of 0.25 mm/12 h for 3 weeks. Starting with distraction, TGF-beta1 was applied in four different dosages (0, 10, 20, and 40 ng/day) at the site of osteotomy through a catheter connected to a subcutaneously implanted miniosmotic pump. Rabbits were killed at the end of the distraction period or 3 weeks later, and histological, densitometric, and biomechanical parameters were assessed. TGF-beta1 treatment had no detectable effect on bone mineral density or histologically determined bone volume in the distraction gap but it increased the amount of fibrous tissue in the callus region. Load to failure in uniaxial tension tended to be lower in TGF-beta1-treated animals. In conclusion, TGF-beta1 treatment during distraction osteogenesis did not have a beneficial effect in this model.

Absorptiometry, Photon↗
PubMed2000

Temporal and spatial expression of bone morphogenetic protein-2, -4, and -7 during distraction osteogenesis in rabbits.

The Ilizarov method of limb lengthening makes use of the fact that osteogenesis is induced at an osteotomy site when distraction is applied. It is unknown at present how the mechanical forces created by distraction are translated into biological signals. Because bone morphogenetic proteins (BMPs) are potent inducers of osteogenesis in many experimental systems, they are obvious candidates for playing a role in this process. In this study, we investigated the temporal and spatial expression of BMP-2, -4, and -7 proteins during distraction osteogenesis using immunohistochemistry. An osteotomy was performed on the right tibiae of white New Zealand rabbits. After a delay of 7 days, distraction was started at a rate of 0.25 mm/12 h for 3 weeks, followed by a 3 week consolidation phase. Each week after osteotomy one rabbit was killed for immunohistochemical studies. Staining for BMP-2, -4, and -7 was evident before distraction was applied and was mainly localized to mesenchymal cells and osteoblastic cells in the periosteal region. After distraction was started, the typical fibrous interzone developed between the osteotomy fragments, where both intramembranous and endochondral ossification were noted. In this area, cells resembling fibroblasts and chondrocytes, but not mature osteoblasts, showed intense staining for all three BMPs. This high level of expression was maintained during the entire distraction phase and then gradually disappeared during the consolidation phase. These results are compatible with the hypothesis that BMPs play an important role in the signaling pathways that link the mechanical forces created by distraction to biological responses.

Animals↗
PubMed1999

Lessons learned about research on premenstrual syndrome.

We discuss specific problems in implementing research to evaluate exercise treatment for premenstrual syndrome (PMS). Modifications of lifestyle, such as implementing exercise regimens, frequently are recommended as treatment for PMS, but evidence supporting this treatment is largely anecdotal. Originally, we designed a study to examine the effects of physical exercise on the symptoms of PMS. Despite initial enthusiasm, the majority of participants dropped out before beginning the active intervention segment of the study. This unexpected attrition resulted in a review of methodology, including recruitment and study design, in an attempt to understand factors related to research on exercise-based treatments of PMS so future researchers would be cognizant of the obstacles inherent in such research. Such understanding will allow research to advance more efficiently by enabling investigators to avoid the pitfalls we identified.

Exercise↗
PubMed1996

Long-term effects of antidepressants on balance, equilibrium, and postural reflexes.

To assess the long-term effects of antidepressant medication on balance, equilibrium, and postural reflexes, we studied 30 patients, ages 20-76 years, who had a diagnosis of depressive disorder (as defined by DSM-III-R criteria) and had been treated with tricyclic antidepressants (TCAs) or selective serotonin reuptake inhibitors (SSRIs) for > or = 1 year. They were assessed by a Balance Master System. The assessment included three tasks: static balance, rhythmic weight shift, and limits of stability. When compared with 30 nonhospitalized healthy controls (of comparable age and the same sex), patients who took TCAs showed impaired balance function in all main indices. The results suggest that the impairment of balance function includes motor coordination, fine-motor control, postural reflexes, maintaining equilibrium, and reaction time. No obvious impairment of balance function was observed in patients who took SSRIs.

Adult↗
PubMed1982

Antihypertensive therapy in patients above age 60 with systolic hypertension. A progress report of the European Working Party on High Blood Pressure in the Elderly (EWPHE).

1. Although systolic blood pressure elevation is responsible for increased incidence of cardiovascular accidents in old people, the preventive benefit of lowering systolic hypertension in elderly has not been confirmed. 2. A double blind study comparing the effects of a placebo and of an active regimen (hydrochlorothiazide-triamterene with or without methyldopa) in people over 60 years with isolated systolic hypertension has been undertaken by the European Working Party on High blood pressure in the Elderly (EWPHE). 3. The actively treated group shows a lowered sitting blood pressure (-15/6 mm Hg), a mild increase of serum creatine, serum uric acid and blood glucose and a mild decrease of serum potassium after two years of treatment when compared to the spontaneous changes observed in the placebo treated group. 4. The study is continuing to evaluate if the blood pressure reduction prevents or reduces the incidence of cardiovascular accidents, although some biochemical changes were provoked by the treatment.

Aged↗
PubMed1982

Influence of anti-hypertensive therapy on serum cholesterol in elderly hypertensive patients. Results of trial by the European Working Party on High blood pressure in the Elderly (EWPHE).

In the European Working Party trial on High blood pressure in the Elderly, patients over 60 are randomly allocated either to receive diuretic capsules containing 25 mg hydrochlorothiazide and 50 mg triamterene or matching placebos. If the blood pressure remains high those receiving active diuretic treatment also receive methyldopa. Those receiving a placebo diuretic area given placebo methyldopa tablets. The study is double blind, started in 1974 and is still in progress. Three hundred and thirty-one patients have now been followed for 1 year and of these 190 have been followed for 2 and 90 for 3 years. After 1 year the serum cholesterol in the placebo group fell by an average of 10.4 mg/100 ml; over 2 years the fall was 16.0 mg/100 ml and over 3 years 20.8 mg/100 ml (6.7%). The corresponding results for the actively treated group were falls of 3.1 mg/100 ml; 20.3 mg/100 ml and 17.3 mg/100 ml (6.6%). Over a period of up to 3 years the average fall in cholesterol was 5.9 mg/100 ml/year in the placebo group and 5.0 mg/100 ml/year in the actively treated group. Thus the changes in serum cholesterol were similar whether the patients received active or placebo medication. In particular there was no evidence for an increase in cholesterol nor for a smaller decrease during diuretic therapy. In the actively treated group the fall in blood pressure in the more hypertensive patients was accompanied by a fall both in haematocrit and serum cholesterol. In patients with less severe hypertension, active treatment was not accompanied by a fall in either hematocrit or cholesterol. These different responses of serum cholesterol in the more and less severe hypertensives in the present study could explain some of the previous conflicting reports on the influence of diuretic treatment on serum cholesterol.

Aged↗
PubMed1977

Detecting the early stages of osteomalacia with the intravenous vitamin D test.

Studies of calcium levels in 400 elderly patients in a hospital geriatric unit showed that many patients (42 percent) had hypocalcemia when referred to the unit and that the incidence of hypocalcemia rises proportionately with advancing age; however, in men, the frequency decreases after age 90. Although hypocalcemia is caused by vitamin D deficiency in a number of patients, in most it is caused by malnutrition. The intravenous vitamin D tests is a simple and reliable procedure for differentiating hypocalcemia due to specific vitamin D deficiency from that due to other causes. We suggest that a 15 percent rise in the serum phosphate level after the intravenous administration of 40,000 units of vitamin D3 indicates the presenceof osteomalacia. Little is known about the sequence of development of detectable bone changes and disturbance of serum calcium, phosphate, and alkaline phosphatase levels in the natural course of osteomalacia. Early treatment of osteomalacia is simple and very rewarding. No effort should be spared in detecting it as soon as possible.

Aged↗
PubMedDate not supplied

Effect of a single botulinum toxin injection on bone development in growing rabbits.

Intramuscular injections with botulinum toxin A (BTX-A) lead to a rapid decrease in muscle mass and force, but the effect of this drug on bone development is unclear. In the present pilot study we evaluated the effect of a one-time injection of BTXA in growing rabbits. Twelve young (weight 1.5 kg) New Zealand rabbits were randomly assigned to receive either BTX-A (total dose 8 units per kg body weight) or sodium chloride 0.9% injections into the left quadriceps and gastrocnemius muscles. Both groups continued to gain weight in a similar manner following the injection. However, when the animals were sacrificed at five weeks after the injection, the group receiving BTX-A had a significant deficit (of 10%) in gastrocnemius muscle mass on the injected side, whereas no significant side-difference was found for the quadriceps. BTX-A injections did not affect the length of the tibia. Nevertheless, bone mineral content of the whole tibia, as measured by dual-energy X-ray absorptiometry, was 7% lower in the BTX-A injected side than on the contralateral side. Peripheral quantitative computed tomography showed that this bone mass deficit was larger in the metaphysis than in the epiphysis or diaphysis. In the diaphysis, the bone mass deficit was due to a reduction in cross-sectional bone dimensions, which equally affected the cross-section of the entire bone, the cortical compartment and the marrow space. BTX-A injections did not have a detectable effect on cortical bone mineral density. The bone mass deficit in the diaphysis thus appeared to be caused by a lack of periosteal bone apposition rather than increased endocortical or intracortical resorption. These preliminary data suggest that intramuscular BTX-A injections can have a deleterious effect on the development of bones that are loaded by the injected muscles.

Animals↗