Bone mineral density in pediatric patients with idiopathic hypercalciuria

Between October 1993 and April 1995, a total of 77 neonates requiring mechanical ventilation were enrolled in this study and were randomly divided into two groups. Group A consisted of 31 premature infants (mean birthweight 1.36 +/- 0.29 kg) with respiratory distress syndrome (RDS) and seven neonates (mean birthweight 3.2 +/- 0.5 kg) with meconium aspiration syndrome (MAS). Group B consisted of 31 premature infants (mean birthweight 1.31 +/- 0.3 kg) with RDS and eight neonates (mean birthweight 3.3 +/- 0.5 kg) with MAS. Infants in group A received synchronized intermittent mandatory ventilation (SIMV) and infants in group B received conventional intermittent mandatory ventilation (CIMV) therapy. In premature infants with RDS, our data showed: (i) the duration of ventilation was significantly shorter (P < 0.05) in the synchronized group (156 +/- 122 h) compared to the conventional group (242 +/- 175 h); (ii) significantly fewer (P < 0.05) patients required reintubation in the synchronized group than in the conventional group (three vs 11 patients); (iii) incidence of severe intraventricular hemorrhage (grades 3 and 4) was significantly lower (P < 0.05) in the synchronized group compared to the conventional group (one vs seven patients); (iv) incidence of bronchopulmonary dysplasia was significantly lower (P < 0.05) in the synchronized group than in the control group (one vs seven patients). In neonates with MAS, our data showed no significant difference (P < 0.05) on duration of ventilation, incidence of reintubation, incidence of pneumothorax or mortality rate between synchronized and control groups.     

Bone mineral density assessment in children with inflammatory bowel disease

BACKGROUND & AIMS: Children with inflammatory bowel disease (IBD) are at risk for osteoporosis because of undernutrition, delayed puberty, and prolonged corticosteroid use. The aim of this study was to compare bone mineral density (BMD) in children with IBD with that in normal children and to assess the effects of nutritional and hormonal factors and corticosteroid dosages on BMD. METHODS: One hundred sixty-two subjects (99 with IBD and 63 healthy sibling controls) were enrolled. Patients underwent anthropometric assessment, pubertal staging, bone age radiography, and BMD assessment by dual energy x-ray absorptiometry of the lumbar spine, femoral neck, and radius. Laboratory evaluations included serum calcium, phosphate, alkaline phosphatase, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, parathyroid hormone, osteocalcin, urinary N-telopeptides, albumin, insulin-like growth factor I, and testosterone or estradiol. Cumulative corticosteroid doses were calculated. RESULTS: BMD Z scores at the lumbar spine and femoral neck were lower in patients with IBD, and lower in those with Crohn's disease compared with those with ulcerative colitis. Low BMD persisted after correction for bone age in girls with Crohn's disease (lumbar spine, P = 0.004; femoral neck, P = 0.002). Cumulative corticosteroid dose was a significant predictor of reduced BMD. BMD did not correlate with measures of calcium homeostasis, except elevated serum phosphate and urine calcium levels in girls. CONCLUSIONS: Low BMD occurs in children with IBD (more in Crohn's disease than in ulcerative colitis), especially pubertal and postpubertal girls. Cumulative corticosteroid dose is a predictor of low BMD, but other factors in Crohn's disease remain undetermined.     

Bone mineral density in periodontally healthy and edentulous postmenopausal women

(Osteoporosis is the most common metabolic disease among postmenopausal women. Reduced masticatory function caused by tooth loss may be a contributing risk factor of osteoporosis. The present study examined the effect of dentate state on skeletal bone mineral density (BMD) in postmenopausal women. Fourteen periodontally healthy dentate subjects (group H; mean age: 64.0 + 5.5 years) and 12 edentulous subjects (group E; mean age: 67.1 + 2.9 years) were randomly selected from the clinics of the departments of Periodontology and Gerodontology, respectively. Informed consent was obtained from all participants. BMD of the lumbar spine (L2-L4) was measured by dual energy x-ray absorptiometry. In addition, occlusal force was measured in 11 group H subjects and 8 group E subjects by using an occlusal diagnostic system. Risk factors associated with osteoporosis including age, calcium intake, physical activity, and cigarette smoking and causes of tooth loss were assessed by interview and questionnaire sent to all participants. The BMD of group H was 1.07 t 0.21 g/cm2 and that of group E was 0.89 + 0.17 g/cm2, which was significantly different(P< 0.05). The occlusal force of group H and E patients was 312.4 + 148 Nand 56.3 + 36 N, respectively, which was significantly different (P< 0.05). Risk factors such as calcium intake, physical activity, and smoking did not differ significantly between the 2 groups. Thus, the periodontally healthy dentate women, who showed about 6 times higher occlusal force than edentulous women, maintained significantly higher BMD of the lumbar spine than edentulous women. Our results suggest that sufficient masticatory function with periodontally healthy dentition may inhibit or delay the progress of osteoporotic change in skeletal bone or that edentulous women may be more susceptible to osteoporosis.     

Bone mineral density in patients on long-term therapy with levothyroxine

The aim of the study was to determine the influence of replacement and suppressive thyroxine therapy on bone mineral density (BMD). 30 postmenopausal women; 19 on replacement therapy (dose 1.22 +/- 0.35 micrograms/kg; duration 11.4 +/- 7.2 years) and 11 on suppressive therapy (dose 1.45 +/- 0.71 micrograms/kg; duration 9.5 +/- 7.2 years). Controls were 60 healthy women matched for age and menopausal status. BMD at the lumbar spine (L2-L4), femoral neck, Ward's triangle and trochanter was measured by dual-energy absorptiometry. Forearm BMD at distal site was measured by single-photon absorptiometry. Mean thyroid hormone values and TSH were within normal limits, although the patients on suppressive therapy had significantly higher T3 (p < 0.05) than the patients on replacement therapy. BMD on each site was significantly lower in the replacement treated group than in controls. BMD in patients on suppressive therapy was lower, but not significantly, compared to controls. Thyroxine therapy could have an adverse effect on BMD. The magnitude of bone loss depends on the serum level of thyroid hormones and on the functional state of thyroid hormone receptor in bone tissue, as well.     

Bone mineral density in women using depot medroxyprogesterone acetate for contraception

OBJECTIVE: To evaluate the possible effects of depot medroxyprogesterone acetate injectable contraception on bone mineral density in reproductive-age women. METHODS: We conducted a population-based cross-sectional comparison of bone mineral density levels in women using depot medroxyprogesterone acetate contraception and in women of similar age not using this method. The study recruited 457 nonpregnant women aged 18-39 years who were enrollees of a Washington state health maintenance organization. One hundred eighty-three women were receiving injections and 274 were not. Bone mineral density at several anatomic sites (spine, femoral neck, greater trochanter, and whole body) was measured using dual-energy x-ray absorptiometry. Data on other factors potentially related to bone density were collected through questionnaire and examination. RESULTS: Overall, age-adjusted mean bone density levels were lower for users of this method than for nonusers at all anatomic sites: The mean difference was 2.5% for the spine (P = .03) and 2.2% for the femoral neck (P = .12). Exposure to depot medroxyprogesterone acetate continued to be significantly (P < .01) associated with decreased bone density at the femoral neck, spine, and trochanter after multivariate adjustment for other risk factors related to bone density. Age-specific comparisons indicated that the major differences in bone density between users and nonusers occurred in the youngest age group (women 18-21 years); the mean femoral neck bone density was 10.5% lower (P < .01) for the exposed women, and differences were consistent (P < .01) across all anatomic sites. We also noted a significant dose-response relation between longer use of depot medroxyprogesterone acetate and decreased bone density levels in this age group (P < .01 for all sites). CONCLUSION: These results provide evidence that contraception with depot medroxyprogesterone acetate, particularly long-term use, may adversely affect bone mineral density levels in young women aged 18-21 years. The implications for future bone health need further study.     

Bone mineral density in patients undergoing bone marrow transplantation for myeloid malignancies

Hitherto the biology of proteolysis in prokaryotes, particularly in archaea, is only poorly understood. We have used the tri-peptide vinyl sulfone inhibitor carboxybenzyl-leucyl-leucyl-leucine vinyl sulfone (Z-L3VS) to study the in vivo function of proteasomes in Thermoplasma acidophilum. Z-L3VS is a potent inhibitor of the Thermoplasma proteasome and is capable of modifying 75 to 80% of the proteasomal beta-subunits in cell cultures. Inhibition of proteasomes has only marginal effects under normal growth conditions. Under heat shock conditions, however, the effects of proteasome inhibition are much more severe, to the extent of complete cell growth arrest. These data suggest that other proteolytic systems may exist that can compensate for the loss of proteasome function in T. acidophilum.     

Bone mineral density and turnover in children with systemic juvenile chronic arthritis

OBJECTIVE: To assess bone mineral status in a group of children with systemic type juvenile chronic arthritis (JCA), which places them at high risk to develop osteoporosis. METHODS: Bone mineral density (BMD) was measured in 17 children aged 6-18 yrs (mean 14.9 +/- 4.5) with systemic JCA and in 18 matched controls by dual energy x-ray absorptiometry. Bone turnover was determined by quantitative bone scintigraphy, using quantitative single photon emission computed tomography based on skeletal uptake of methylene diphosphonates (MDP uptake). Serum concentrations of minerals, osteocalcin, and bone alkaline phosphatase were determined. Nutrient intake was assessed by a 24 hour dietary recall. RESULTS: Patients with systemic JCA who received corticosteroid therapy had significantly reduced BMD in both the lumbar spine (p < 0.05) and the femoral neck (p < 0.05) compared to controls, whereas BMD values of the non-steroid systemic JCA patients were not different from controls. Bone turnover measurement by MDP uptake showed no difference between patients with JCA and controls. Levels of calcium, phosphorus, alkaline phosphatase. and osteocalcin were within normal limits in all patients. CONCLUSION: Patients with systemic JCA receiving longterm steroid treatment may develop a significant decrease in BMD. The normal MDP uptake values together with normal osteocalcin levels that we observed in our patients indicate that their disease is not associated with enhancement of bone turnover rates. These observations might have therapeutic implications for prevention and management of osteoporosis in JCA.     

Antecedents of pre-competition achievement goals in elite junior tennis players

The aim of this study was to integrate both dispositional and situational factors to examine their interactive ability to predict pre-competitive goal states of task and ego involvement in a sample of National junior tennis players. The Task and Ego Orientation in Sport Questionnaire (Chi and Duda, 1995) and a set of single-item assessments of match goal orientation represented the dispositional measures in the study. These were administered at home, away from the tennis environment. The situational antecedents of pre-match task and ego involvement were assessed by an 11-item Match Context Questionnaire, which was administered to the players (n = 119) within 1 h of their singles match start time at the National Junior Championships. The Match Context Questionnaire also measured the personal task- and ego-involved goal states of the player with respect to the upcoming singles match (i.e. 'state' goals). Factor analysis of this questionnaire revealed three situational factors which cumulatively accounted for 64.7% of variance in the match context: social/personal perceptions of ability; perceived state goal preference of significant others; and match value. Moderated hierarchical regression analyses revealed significant main effects of the dispositional and situational factors on the different goal types. Specifically, perceptions of significant others, the achievement value of the match and perceptions of ability were the major predictors of task involvement. The pre-match intensity of ego involvement was predicted by ego orientation combining with perceptions of significant others and match value. These findings reinforce the need for researchers to consider the importance of both dispositional and situational variables when predicting goal involvement in competitive contexts.     

Bone mineral density of the internal auditory meatus by quantitative computed tomography

The bone mineral density of the internal auditory meatus was investigated by means of quantitative computed tomography in 20 normal subjects (40 ears). Investigated portions of the internal auditory meatus were the porus anterior and posterior and the fundus anterior and posterior. Two other portions of the ear, the bony vestibule and lateral wall of the mastoid, were also investigated. The bone density values (calcium carbonate equivalent value) for each portion were analyzed statistically. The following results were obtained: 1) There was no significant difference between the right and left values in any portion. 2) The highest mean value was found in the fundus posterior, the lowest in the porus anterior. There was a significant difference between the values of the fundus and porus. Bone hardness generally correlates with bone density. Thus, the bone hardness of the porus of the internal auditory meatus was appraised to be lower than that of the fundus. These results suggest that this is one of the factors promoting enlargement of the internal auditory meatus in acoustic neuroma.     

Bone mineral density in thyroxine treated females with or without a previous history of thyrotoxicosis

Alterations in lipid metabolism characterized in major part by a decrease in lipoprotein lipase (LPL) activity in adipose tissue are a central feature of cachexia from chronic infection or malignancy. These metabolic derangements may be mediated in large part through endogenous host proteins produced in response to various pathological stimuli. Differentiation factor/leukaemia inhibitory factor (D-factor) is a cytokine whose functions overlap those of tumour necrosis factor-alpha (TNF), IL-6 and IL-1. Recombinant murine D-factor produced a dose- and time-dependent inhibition of heparin-releasable LPL activity in differentiated 3T3-L1 adipocytes. Although 2-10 fold less potent than recombinant murine TNF, D-factor inhibited LPL activity at concentrations of 1-10 ng/ml. When added together, D-factor and TNF produced a synergistic inhibition of LPL activity. Interleukin 6 (IL-6) was 100-fold less potent than D-factor; 0.1 ng/ml of D-factor or 10 ng/ml of IL-6 caused a 50% inhibition of LPL activity. D-factor and TNF increased IL-6 production in 3T3-L1 cells. Ten ng/ml of D-factor or 1.0 ng/ml of TNF stimulated the release of < 1 ng/ml of IL-6 and inhibited LPL activity to 11 +/- 3% and 3 +/- 2% of control, respectively, whereas 50 ng/ml of recombinant IL-6 was required to decrease LPL activity to 24 +/- 19% of control. TNF produced a marked decrease in LPL mRNA, whereas D-factor had minimal or no effect at doses which inhibited LPL activity almost completely. Western blot analysis of cell extracts showed that TNF caused a greater decrease in LPL protein production than D-factor.2+ with TNF, may contribute to the manifestations of cachexia.     

Bone lesion in multiple myeloma--bone mineral density measured by dual energy X-ray absorptiometry in multiple myeloma]

The paper discusses some of the factors that affect the onset of osteoporosis, and provides an original model for rehabilitation procedure in this disorder. The type of motor exercises used are indicated, and the sequence in which they are done. There is also a discussion of the significance of the application of physiotherapy equipment. Attention is also drawn in the paper to the possibility of the patient applying rehabilitation procedures independently, under only periodic supervision by the physician.     

Bone mineral density and the results of chiari pelvic osteotomy for osteoarthritis of the hip

We present yotari, a novel neurological mutant mouse whose mutation is transmitted in an autosomal recessive manner. The phenotype of yotari is very similar to that of reeler. yotari mutants are recognizable by their unstable gait and tremor and by their early deaths at around the time of weaning. The cerebella of homozygous yotari are hypoplastic and have no foliation. A molecular and a granular cell layer can be identified, but Purkinje cells are scattered throughout both the granular layer and white matter. The laminar structure of the cerebral cortex and the hippocampal formation are also distorted. To test whether the mutated gene in yotari is the reeler gene, reelin, yotari heterozygotes were mated with reeler homozygotes or heterozygotes. The absence of abnormal offspring indicated that the yotari gene is distinct from reelin. Furthermore, expression of mRNA and protein of reelin was verified by Northern blotting and immunohistochemistry using a CR-50 monoclonal antibody (mAb) which is specific to Reelin, the reelin gene product. Although the mutation of several genes, including cyclin-dependent kinase 5 (Cdk 5), p35 and LIS1, 45 kDa subunits of platelet-activating factor acetylhydrolase (PAF-AH) Ib, in Miller-Dieker lissencephaly syndrome (MDS) has been reported to cause abnormal laminar structure in the brain, no abnormality was found in yotari by Western blotting with antibodies (Ab's) against these molecules. The close similarity of the phenotypes of yotari and reeler and the expression of reelin in yotari may suggest that the gene mutated in yotari encodes a molecule that is on the same signaling pathway as Reelin, the product of reelin. yotari will provide valuable clues to explore the molecular mechanism of neuronal migration and orderly laminar structure formation of the brain.     

Bone mineral density and bone markers in relation to vitamin D receptor gene polymorphisms in Chinese men and women

Whether vitamin D receptor gene (VDRG) polymorphism can be used as a predictor for bone turnover rate or bone mass remains controversial. Its role within various ethnic populations are also unsettled. We examined VDRG polymorphism using restrictive enzymes Bsm-I, Apa-I, and Taq-I in 155 men aged 22-88 and 113 premenopausal women aged 40-53. The bone mineral density (BMD) of the vertebrae (L2-4), proximal femur, and total body bone mineral content (tb-BMC) (women only), as well as urinary N-terminal crosslinked fragment of type I collagen (NTX), serum osteocalcin, bone isozyme of alkaline phosphatase, and caboxyterminal propeptide of type I procollagen levels were measured. Chinese men and women exhibited a low prevalence for B (absence of Bsm-I restriction site) phenotypes than white and Japanese. Within the tested samples there were 0.4% BB homozygotes, 6.7% Bb heterozygotes, and 93% bb homozygotes. The distributions of Apa-I polymorphism (9.0% AA, 42.5% Aa, and 48.5% aa) also differed from those reported for the white populations. Most of the Chinese men and women were TT homozygous (96.6%). A comparison of actual values and values adjusted for age and weight of tb-BMC and BMD at the lumbar spine, Trochanter, Ward's triangle, and femoral neck showed no significant difference among three subgroups in each of the three sets of polymorphism. Furthermore, the actual values and adjusted values (adjusted for age) of the four bone markers, respectively, showed no significant differences. We conclude that given the very low prevalence of the suspected high risk genotypes (B, A, and t), and the lack of difference among the polymorphic subgroups, VDRG polymorphism may not be an important determinant of the bone turnover rate and bone mass of Chinese men and women.     

Exercise and bone mineral density

A decrease in physical activity may lead to an increased loss of bone and an increase in the incidence of osteoporotic fractures. Studies have demonstrated increases in bone formation in animals and increases in bone mineral density in humans. Studies of animals show that bone has enhanced physical and mechanical properties following periods of increased stress. Strains which are high in rate and magnitude, and of abnormal distribution, but not necessarily long in duration, are best for inducing new bone formation, resulting in the strengthening of bone by increased density. Cross-sectional studies show that athletes, especially those who are strength-trained, have greater bone mineral densities than nonathletes, and that strength, muscle mass and maximal oxygen uptake correlate with bone density. Longitudinal training studies indicate that strength training and high impact endurance training increase bone density. Strain induction, the deformation that occurs in bone under loading, may cause a greater level of formation and an inhibition of resorption within the normal remodelling cycle of bone, or it may cause direct activation of osteoblastic bone formation from the quiescent state. Various mechanisms have been proposed for the transformation of mechanical strain into biochemical stimuli to enhance bone formation. These include prostaglandin release, piezoelectric and streaming potentials, increased bone blood flow, microdamage and hormonally mediated mechanisms. These mechanisms may act on their own or in concert, depending on the loading situation and the characteristics of the bone.