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PubMed2001

Dietary boron supplementation enhances the effects of estrogen on bone mineral balance in ovariectomized rats.

The present study investigated whether boron would enhance the action of 17beta-estradiol (E2) or parathyroid hormone (PTH) on bone mineral balance in ovariectomized (OVX) rats. Forty-three days after OVX, the rats were treated for 5 wk with vehicle, boron (5 ppm as boric acid), E2 (30 microg/kg/d, sc), PTH (60 microg/kg/d, sc), or a combination of boron and E2 or PTH. Bone mineral balance was assessed by measuring apparent absorption, excretion, and retention of calcium (Ca), phosphorus (P), and magnesium (Mg). Serum Ca, P, Mg, and osteocalcin were also measured in this experiment. Boron alone had no effects on food consumption, weight gain, bone mineral balance, and serum levels of Ca, P, Mg, and osteocalcin. E2 alone increased serum P and Mg and decreased serum osteocalcin, but it had no effect on bone mineral balance. The combination of boron and E2 markedly improved apparent absorption of Ca, P, and Mg. In addition, the combination treatment increased the apparent retention of Ca and Mg (but not P) and also increased serum Ca and Mg but not serum P. On the other hand, boron cotreatment did not prevent the E2-induced reduction in serum osteocalcin in OVX rats. PTH alone significantly increased serum Ca, P, Mg, and osteocalcin concentrations, although it had no effect on bone mineral balance. Contrary to the boron-E2 combination treatment, the combination of boron and PTH did not enhance bone mineral balance. However, inasmuch as boron-PTH cotreatment did not enhance the stimulatory action of PTH on serum Ca, P, and osteocalcin, boron completely abolished the stimulatory effect of PTH on serum Mg. In conclusion, we have demonstrated for the first time that although boron by itself has no effect on bone mineral homeostasis, it appears to have synergistic enhancing effects on the action of E2 on Ca and Mg homeostasis in OVX rats.

Animals↗
PubMed2006

In vitro re-mineralization of demineralized bone matrix in human serum.

The aim of this study was to develop an in vitro re-mineralization model in human serum. For this purpose a commercially produced demineralized human bone matrix (DBM) was incubated in samples of human serum pools obtained from two physiologically different groups. The first group consisted of young males and the second of older females. After incubation periods of 4 and 7 days at 37 degrees C, changes in the levels of calcium and inorganic phosphate content of the serum and DBM samples were measured. The results of the study showed that the change in mineral content of serum and DBM samples in both study groups was statistically significant. The decrease in serum calcium content and increase in DBM inorganic phosphate content were significant in the young group for longer incubation times. In the older group, both serum calcium and inorganic phosphate decreased and DBM mineral content increased for the same incubation time. When the two physiological groups were compared, statistically significant differences were identified for changes in mineral levels in both serum and the DBM samples. These data indicate that the mineral content of human serum decreases and that of DBM increases when these two materials are incubated together. These changes provide evidence for the re-mineralization of DBM. The model described here could also detect a difference in re-mineralization capability between two different groups of human sera.

Adult↗
PubMed1993

Reduced bone mineral content in adult patients with growth hormone deficiency.

Bone mineral content was measured in a follow-up study of adult patients with hypopituitarism and growth hormone deficiency. There were 95 patients (59 males, mean age 54.0 years, range 21-74 years; 36 females, mean age 53.5 years, range 31-73 years). Routine replacement therapy with cortisone acetate and L-thyroxine was given. All males that were gonadal deficient were on proper testosterone therapy, except in four patients who were treated separately. Bone mineral content (g/cm) was measured using dual-photon absorptiometry in the third lumbar vertebra. Bone mineral content in the patients was compared with a control population (N = 413, 25-74 years of age). Bone mineral content was significantly lower in males (N = 55, p < 0.05) compared with controls. In females, bone mineral content was significantly lower both among the subjects with untreated gonadal deficiency (p < 0.001) and among those with treated gonadal deficiency and normal premenopausal gonadal function (p < 0.005) compared with controls. To summarize, patients with hypopituitarism on routine replacement therapy but not growth hormone have a lower bone mineral content than the controls. The reduced bone mineral content might be a result of untreated growth hormone deficiency.

Adult↗
PubMed1998

Effects of testosterone replacement therapy on cortical and trabecular bone mineral density, vertebral body area and paraspinal muscle area in hypogonadal men.

Loss of bone and muscle mass are major findings of male hypogonadism. In order to determine the long-term effect of testosterone replacement therapy on spinal bone and muscles, the trabecular and cortical bone mineral density, vertebral body area and paraspinal muscle area were assessed by quantitative computed tomography in 32 testosterone-substituted patients, aged 18-74 years, with idiopathic hypogonadotropic hypogonadism (n=6), pituitary insufficiency (n=5), Klinefelter syndrome (n=12) or other forms of primary hypogonadism (n=9). They were followed for a mean period of 3.2+/-1.7 years (mean+/-S.D.), ranging from 1 to 7 years. A significant correlation between initial serum testosterone levels and bone mineral density was found in patients with congenital forms (r=0.58; P<0.05) but not in those with acquired forms. A significant increase in trabecular and cortical bone mineral density (P<0.001) was documented in the course of replacement therapy in all patients regardless of the type of hypogonadism and age of patients. A slight but significant increase in paraspinal muscle area was observed if all patients were taken together (P<0.01). The area of paraspinal muscle correlated with body weight (r=0.58; P<0.001) and moderately with trabecular bone mineral density (r=0.4; P<0.01). Its increase did not correspond to the change observed for trabecular and cortical bone mineral density. Vertebral body area did not change over time. It correlated only with height and weight but not with bone mineral density. In conclusion, testosterone therapy of hypogonadal men improves both trabecular and cortical bone mineral density of the spine independently of age and type of hypogonadism while vertebral area remains unchanged. The effects seen on paraspinal muscles emphasize the clinical benefit of adequate replacement therapy for the physical fitness of hypogonadal men.

Adolescent↗
PubMed2001

A study to verify a reported excess of chromosomal aberrations in blood lymphocytes of Namibian uranium miners.

This report describes a study to verify an earlier report of excess chromosomal damage in the blood lymphocytes of uranium miners. Coded blood samples from 10 miners and 10 controls were analyzed conventionally for unstable aberrations and by FISH for translocations. Conventional analysis, scoring 1000 metaphases per subject, showed no significant difference between miners and controls in the frequencies of chromosome- and chromatid-type aberrations. Investigators at two laboratories undertook FISH analyses, each scoring 4000 metaphases per subject. When the data from each laboratory were examined separately, one found slightly more translocations in the miners while the other found fewer. In neither case was the difference significant at the 95% level of confidence. Combining the data likewise showed no significant excess of damage in the miners. This applied to simple one- and two-way translocations and to cells with complex exchanges. There was no correlation between levels of translocations and total lifetime doses from occupational and/or background irradiation. A borderline significant excess of rogue cells was found in the miners. This may be a chance observation, as these rare, highly abnormal cells are considered to be unrelated to radiation exposure and are probably due to a virus. The overall conclusion is that the frequency of chromosomal damage in the miners did not exceed that in the controls. Therefore, the result of the earlier study was not confirmed.

Chromosome Aberrations↗
PubMed1999

Enhanced production of mineralized nodules and collagenous proteins in vitro by calcium ascorbate supplemented with vitamin C metabolites.

BACKGROUND: Vitamin C or ascorbate is important in wound healing due to its essential role in collagen synthesis. To study wound healing in the periodontium, cells adherent to expanded polytetrafluoroethylene (ePTFE) augmentation membranes, recovered from edentulous ridge augmentation procedures, have been established in culture in our laboratories. The objective of this study was to determine whether treatment of these cells with a calcium ascorbate, which contains vitamin C metabolites (metabolite-supplemented ascorbate), would increase the production of collagenous protein and mineralized tissue in vitro, as compared to unsupplemented calcium ascorbate (ascorbate). METHODS: Cells derived from ePTFE membranes were cultured with beta-glycerophosphate and the test agents for 2 to 5 weeks, and the surface areas of the cell cultures occupied by mineralized nodules were measured using computerized image analysis. One experiment tested the effects of calcium threonate, one of the vitamin C metabolites in metabolite-supplemented ascorbate. Incorporation of radioactive proline and glycine was used as a measure of total protein (radioactivity precipitated by trichloracetic acid) and collagenase-digestible protein (radioactivity released by collagenase digestion.) Co-localization of collagen and fibronectin was examined by immunofluorescence. RESULTS: In vitro treatment of these cells with metabolite-supplemented ascorbate increased the area of the cell cultures occupied by mineralized nodules after 5 weeks. Cell cultures treated with metabolite-supplemented ascorbate also exhibited significant increases in total protein. The increase in collagenous proteins in these cultures accounted for 85% of the increase in total protein. The greatest difference between treatment groups was observed in the cell-associated fraction containing the extracellular matrix. The additional collagen exhibited normal co-distribution with fibronectin. In cultures treated with ascorbate spiked with calcium threonate, the area of mineralized tissue was significantly greater than in ascorbate-treated cultures, but was less than that observed in cultures treated with metabolite-supplemented ascorbate. CONCLUSIONS: In vitro treatment with ascorbate containing vitamin C metabolites enhanced the formation of mineralized nodules and collagenous proteins. Calcium threonate may be one of the metabolites influencing the mineralization process. Identifying factors which facilitate the formation of mineralized tissue has significant clinical ramifications in terms of wound healing and bone regeneration.

Alveolar Ridge Augmentation↗
PubMed2000

Platelet-derived growth factor enhancement of a mineral-collagen bone substitute.

BACKGROUND: Anorganic bovine bone-collagen matrix is commercially available for bone regeneration procedures. Platelet-derived growth factor-BB (PDGF-BB) has been demonstrated to stimulate bone formation in vivo and in vitro. It was the aim of these studies to examine 1) the interaction of this mineral-collagen matrix with PDGF-BB and 2) determine if the adsorption of PDGF-BB to the mineral-collagen matrix stimulates osteoblastic cell proliferation above that of the untreated matrix. METHODS: Measurement of PDGF-BB adsorption and release was accomplished using 125I radiolabeled growth factor. The PDGF-BB was incubated with the anorganic bovine bone-collagen matrix and the amount which adsorbed was determined. In the release studies, radiolabeled PDGF-BB was adsorbed to the matrix material, then the samples were incubated in buffer for various time periods. The amount of PDGF-BB retained on the matrix was measured and the percent of growth factor released calculated. The biological activity was tested in an in vitro assay with primary culture neonatal rat osteoblastic cells. Osteoblastic cells were cultured on bone mineral-collagen matrix with known amounts of adsorbed PDGF-BB. Proliferation of the cells was assessed by 3H-thymidine incorporation and cell attachment measured by prelabeling cells with 3H-leucine. RESULTS: PDGF-BB adsorbed to the mineralized-collagen matrix material in a rapid, concentration-dependent fashion. The growth factor was slowly released from the matrix such that approximately 30% of the adsorbed protein was liberated over 10 days. PDGF-BB treated mineralized-collagen matrix displayed significantly (P < 0.05, ANOVA) enhanced proliferation of cultured osteoblastic cells compared to the mineralized-collagen matrix alone. CONCLUSIONS: These results suggest that PDGF-BB is rapidly adsorbed then slowly released from the anorganic bovine bone-collagen matrix. PDGF-BB adsorbed to this material is able to stimulate proliferation of the attached osteoblastic cells. These data suggest that it may be clinically feasible to adsorb PDGF to this bone-collagen matrix and that this combination of bone growth factor and mineral-collagen matrix has the potential for clinical applications.

Adsorption↗
PubMed2001

Extraction separation and electrothermal atomic absorption spectrometric determination of thallium in some sulfide minerals.

A method for thallium determination in some sulfide minerals (sphalerite, galena, orpiment and realgar) by electrothermal atomic absorption spectrometry has been proposed. Mineral samples were dissolved in a mixture of HNO3 and HCl. The effect of interfering elements (Zn, Pb and As) on the determination of Tl in the investigated minerals was studied. These investigations show that it is not possible to determine thallium directly from solutions obtained by dissolution of minerals in mineral acids, because these matrix elements tend to decrease the absorbance of thallium. Also, it was found that the investigated minerals contain iron that tends to increase the absorbance of thallium. Therefore, a method for extraction of thallium with isoamyl acetate from 10 mol/l HCl media was proposed. In these conditions, Zn, Pb and As remain in the inorganic phase, but iron and thallium are extracted into organic phase. Reextraction of iron from the organic layer was performed with 4 mol/l H2SO4. The determination of thallium was performed in the organic phase using Pd as modifier. The investigated sulfide minerals originated from different mines from the Republic of Macedonia. The relative standard-deviation range was between 2.20 to 3.92%. The detection limit of the method (calculated as 3SD of the blank) was found to be 0.05 microg/g.

Journal Article↗
PubMedDate not supplied

Coupled abiotic-biotic mineralization of 2,4,6-trinitrotoluene (TNT).

Munitions wastes such as TNT are widespread contaminants in soils and ground waters. We investigated a coupled abiotic-biotic treatment scheme for remediation of aqueous solutions of TNT. Mineralization of aqueous TNT (0.22 mM) was initially optimized with minimum reactant use (Fe3+ and H2O2) in light-assisted and dark, modified Fenton reactions at acidic and neutral pH. Complete TNT degradation occurred under all reaction conditions within 24 h. Using the optimum reactant concentrations, coupled abiotic-biotic reactions showed an increase in TNT mineralization, from 47 to 80%, after biomass addition to the acidic, dark Fenton-like reaction. Comparable increases of TNT mineralization were observed under neutral pH with similar reaction conditions. In light-assisted Fenton-like reactions at neutral pH, no increase in cumulative TNT mineralization (66%) was seen in coupled abiotic-biotic reactions. Abiotic photo-Fenton-like reactions alone, at acidic pH, produced complete TNT mineralization and required no biotic assistance. While light-enhanced Fenton reactions alone can provide high levels of TNT mineralization, the dark abiotic-biotic reaction scheme has perhaps a wider use due to a similar extent of TNT mineralization in the absence of light, leading to possible applications in soil slurry and in situ processes in the subsurface.

Biodegradation, Environmental↗
PubMedDate not supplied

A comparison of in situ methods for measuring net nitrogen mineralization rates of organic soil amendments.

In situ incubation methods may help provide site-specific estimates of N mineralization from land-applied wastes. However, there are concerns about the reliability of the data generated by the various methods due to containment artifacts. We amended a sandy soil with either poultry manure, biosolids, or yard-waste compost and incubated the mixtures using four in situ methods (buried bags, covered cylinders, standard resin traps, and "new" soil-resin traps) and a conventional laboratory technique in plastic bags. Each incubation device was destructively sampled at 45-d intervals for 180 d and net N mineralization was determined by measuring the amount of inorganic N that accumulated in the soil or soil plus resin traps. Containment effects were evaluated by comparing water content of the containerized soil to a field-reference soil column. In situ incubation methods provided reasonable estimates of short-term (< 45 d) N mineralization, but long-term (> 45 d) mineralization data were not accurate due to a variety of problems specific to each technique. Buried bags and covered cylinders did not retain mineralized N due to water movement into and out of the containers. Neither resin method captured all of the mineralized N that leached through the soil columns, but the new soil-resin trap method tracked field soil water content better than all other in situ methods evaluated. With further refinement and validation, the new soil-resin trap method may be a useful in situ incubation technique for measuring net N mineralization rates of organic soil amendments.

Animals↗
PubMedDate not supplied

[Bone mineral density: correlation with body weight, height, bone age and insulin-like growth factor].

OBJECTIVE: To evaluate bone mineral density and bone mineral content of skeleton and lumbar spine of pre-pubertal children and to correlate results thus found with sex, bone age, body weight, height and insulin-like growth factor 1 serum level. METHODS: 26 boys and 12 girls aged between 7 and 8 years old, students from a São Paulo public school, were studied. They all presented weight and height between 2.5 and 97.5 percentiles of the Brazilian childreńs curve, lack of secondary sex characteristics, no reports on chronic diseases and normal physical examination. Bone age was determined from radiograms of the left hand and wrist. Serum levels of insulin-like growth factor 1 were measured by radioimmunoassay. Bone mineral density and bone mineral content were measured in skeleton and lumbar spine using a dual X-ray absorptiometry equipment. RESULTS: The mean values of skeleton bone mineral density found were 0.812 -/+ 0.057 g/cm(2) in the girls and 0.839 -/+0.053 g/cm(2) in the boys, while the respective mean lumbar values were 0.649 -/+ 0.092 g/cm(2) and 0.657 -/+ 0.062 g/cm(2). The mean values of skeleton bone mineral content found were 840 -/+ 181g in the girls and 919 -/+ 133 g in the boys, while the respective lumbar values were 13.3 -/+ 3,0g and 14.5 -/+ 2,4. It was found that the bone mass of children at this age corresponds to about 50% of the bone mass pick found in the young adult. No significant bone mass differences between sexes were found. No correlation was found between bone mass and insulin-like growth factor 1 serum levels. Positive correlations between bone mass and body weight and bone age were found. CONCLUSIONS: In pre-pubertal children (1) the analysis of bone mass should be interpreted mainly as a function of body weight and (2) bone mineral density of the lumbar spine and skeleton correlate with bone age and may represent an additional parameter of skeleton maturation.

English Abstract↗
PubMed1993

Bone mineral normative data in Malmö, Sweden. Comparison with reference data and hip fracture incidence in other ethnic groups.

The bone mineral mass was measured in 324 residents of the city of Malmö, Sweden, by dual energy roentgen absorptiometry (DEXA) using the Lunar DPX equipment--total body, hip, and lumbar vertebrae. The bone mineral content of the wrist was also measured with single photon absorptiometry (SPA) in 88 of the individuals. Weight, height, and vertebral height, as well as body fat, lean body mass, menarcheal age, menopausal age, and hand grip strength were determined. Measurements were compared with reference bone mineral content values from the United States, Japan, and France--also hip fracture incidence was compared. All bone mineral values decreased with age. A good correlation was found between the DEXA technique of total body bone mineral and the forearm SPA values. The bone mineral content was correlated with lean body mass and weight. The Malmö bone mineral content was on the same level as in the United States, but higher than in Japan and France. The comparatively high risk of fragility fractures in the Scandinavian countries compared with most other settings cannot be explained by low bone mass.

Adult↗
PubMed2005

[Bone mineral density in leukemic children after completing one month of chemotherapy].

BACKGROUND: An important loss of bone mineral density, associated to pain and fractures, has been reported in children with acute lymphoblastic leukemia (ALL). AIM: To measure bone mineral density among children with acute lymphoblastic leukemia (ALL) that completed the remission induction phase with chemotherapy, that lasts 30 days. PATIENTS AND METHODS: children with ALL, admitted to the oncology unit of a general hospital were considered eligible for the study. body composition and bone mineral density were measured by dual energy x ray absorptiometry (DEXA). each child with ALL was paired with a healthy control. RESULTS: Fourteen children age 1 to 11 years, completed the study, Spine and femoral bone mineral densities were significantly lower than in their matched controls. No differences in total body bone mineral density or content were observed. Children with ALL had a lower fat free mass and a higher fat mass than their matched controls. There was a significant correlation between fat free mass and bone mineral content. CONCLUSIONS: After one month of chemotherapy, children with ALL had a lower bone mineral density in the spine and femur and a lower fat free mass.

Absorptiometry, Photon↗
PubMed1994

Effect of glucocorticoid replacement therapy on bone mineral density in patients with Addison disease.

OBJECTIVE: To study the influence of glucocorticoid replacement therapy on bone mineral density. DESIGN: Cross-sectional. SETTING: University hospital in the Netherlands. PATIENTS: 91 patients with Addison disease who had been receiving glucocorticoid replacement therapy for a mean of 10.6 years (range, 0.5 to 36.5 years). MEASUREMENTS: Bone mineral density of the lumbar spine and both femoral necks using a dual-energy x-ray absorptiometer and basal serum concentrations of adrenocorticotropin, gonadal hormones, and adrenal androgens. RESULTS: Decreased bone mineral density (less than 2 standard deviations [SD] of the mean value of an age-matched reference population) was found in 10 of 31 men (32%; 95% Cl, 17% to 51%) and in 4 of 60 women (7%; Cl, 2% to 16%). No statistically significant differences were found between men and women with regard to age, duration of glucocorticoid substitution, or glucocorticoid dose, either in absolute quantities or when expressed per kilogram of body weight. However, in men with decreased bone mineral density, the daily hydrocortisone dose per kilogram of body weight (0.43 +/- 0.08 mg/kg; mean +/- SD) was significantly (P = 0.032) higher than in men with normal bone mineral density (0.35 +/- 0.10 mg/kg). After correction for possible confounding variables, a significant linear correlation was found between hydrocortisone dose per kilogram of body weight and bone mineral density of the lumbar spine in the men (regression coefficient, -0.86; Cl, -1.60 to -0.13; P = 0.029) but not in the women. CONCLUSIONS: Long-term treatment with standard replacement doses of glucocorticoids may induce bone loss in men with Addison disease. Adjustment of glucocorticoid therapy to the lowest acceptable dose is mandatory in Addison disease, and regular measurement of bone mineral density may be helpful in identifying men at risk for the development of osteoporosis.

Addison Disease↗
PubMed1996

Effect of hormone replacement therapy on bone mineral density in postmenopausal women with mild primary hyperparathyroidism. A randomized, controlled trial.

BACKGROUND: Most patients with primary hyperparathyroidism are postmenopausal women. The presence of osteopenia in persons with mild primary hyperparathyroidism is considered an indication for parathyroidectomy. No prospective, controlled trials have assessed medical therapies for osteopenia in primary hyperparathyroidism. OBJECTIVE: To examine the effects of estrogen-progestin therapy (hormone replacement therapy) on bone mineral density and biochemical indices in postmenopausal women with mild primary hyperparathyroidism. DESIGN: Double-blind, randomized, placebo-controlled trial. SETTING: University teaching hospital. PATIENTS: 42 postmenopausal women with mild primary hyperparathyroidism. INTERVENTION: Patients were randomly assigned to receive either conjugated estrogens, 0.625 mg/d, and medroxyprogesterone, 5 mg/d, or placebo. MEASUREMENTS: Bone mineral densities of the total body, lumbar spine, proximal femur (femoral neck, Ward triangle, trochanter), and proximal forearm were measured every 6 months using dual-energy x-ray absorptiometry. Biochemical indices of bone turnover and calcium metabolism were measured at baseline, 6 months, and 2 years. RESULTS: In the placebo group, bone mineral densities of the total body and the proximal forearm decreased significantly from baseline (mean +/- SE, -2.3% +/- 0.7% [p = 0.005] and -3.5% +/- 1.2% [p = 0.01], respectively). At the other sites, bone mineral density also tended to decline. In the hormone replacement therapy group, bone mineral density increased from baseline in the total body (1.3% +/- 0.4%; P = 0.004), lumbar spine (5.2% +/- 1.4%; p = 0.002), and femoral neck (3.4% +/- 1.5%; p = 0.05). The between-group differences in bone mineral density at the end of the study ranged from 3.6% to 6.6% and were significant at all sites (P > 0.001 and P < 0.05) except for the Ward triangle (p = 0.06). In the hormone replacement therapy group, serum alkaline phosphatase levels decreased by 22% (p = 0.0004 compared with baseline), urinary hydroxyproline excretion decreased by 42% (p = 0.0004), urinary N-telopeptide excretion decreased by 54% (p = 0.001), and urinary calcium excretion decreased by 45% (p = 0.007). Hormone replacement therapy did not change levels of serum ionized calcium or intact parathyroid hormone. CONCLUSIONS: Although hormone replacement therapy has little effect on serum calcium levels, it suppresses bone turnover, reduces urinary calcium excretion, and increase bone mineral density throughout the skeleton in postmenopausal women with mild primary hyperparathyroidism. This therapy is thus an important management option for these patients.

Aged↗
PubMed2000

[Change in maternal bone mineral density during pregnancy and relationship between the density and foetus growth--a prospective study].

In order to study change in maternal bone mineral density during pregnancy and its relationships with bone metabolism and maternal perinatal factors including foetus growth, bone mineral density and bone metabolic markers were measured in 45 pregnant women aged 26-35 years. Specifically, bone mineral density was measured twice, first at 8-20 weeks of gestation and secondly within two weeks postpartum by ultrasonic bone densitometry, while bone metabolic markers were assessed at 8-20 and 26-30 weeks of gestation and at one week postpartum. Bone mineral density and metabolic markers were also examined in 35 non-pregnant controls, twice with a six-month interval. The results of the measurements and subsequent examinations based thereon were as follows: 1. Stiffness as an index of bone density decreased significantly during pregnancy (mean: -4.3%), with wide variation among individuals (-20%-(+)11%). Stiffness in controls did not show any significant change within the 6 months. 2. During pregnancy, bone alkaline phosphatase and osteocalcin levels were significantly lower while urinary hydroxyproline levels (H.P/Cre) were significantly higher than in controls. Significant negative correlations were found between change rate in stiffness and HP/Cre measured at second trimester and postpartum. These results indicate that bone formation is reduced while bone resorption is increased during pregnancy, and that stiffness index reflects the extent of bone resorption. 3. Pre-pregnancy BMI and weight gain during pregnancy could not be linked with change in bone mineral density. 4. The women with greater bone density demonstrated a greater extent of loss postpartum. 5. Postpartum bone mineral density showed a significant, positive correlation with baby birth weight and height. Higher preservation of maternal bone mass is important not only for the mother's health but also for the baby's. Ultrasonic bone densitometry was found to be useful for measuring bone mineral density because it could detect small changes during pregnancy reflecting bone metabolism.

Adult↗
PubMed1975

Sexual dimorphism in dentition mineralization.

This study determined for 121 boys and 111 girls of the serial experimental group of the Burlington Growth Centre the age, time interval and age sequence of 14 stages of mineralization of all tooth types. The two sexes differed significantly in the age at which the stages of tooth mineralization appeared, and in the length of the interstage intervals. In the canines, there was maximum sex difference in mineralization, which was almost 20 per cent and resulted from a delay in the boys. Changes in sequence of mineralization were due to delay rather than to acceleration. Sex differences in tooth mineralization manifested themselves before puberty, and mineralization was not accelerated at puberty. In contrast, post-pubertal mineralization of third molars appeared to be accelerated in both sexes and occurred earlier in the boys.

Age Factors↗
PubMed1998

[The role of basic fibroblast growth factor on expression of mineralization of periodontal ligament cell population and clones].

OBJECTIVE: To determine the effect of basic fibroblast growth factor (bFGF) on mineraliztion of PDL cell clone. METHODS: The PDL tissue that derived from three human donors was cultured and cells were cloned. The mineralizing ability were detected with or without bFGF treatment in the presence of dexamethasone. Cloned progenitor populations were assayed for their constitutive capacity to bind CAP and express ALP. RESULTS: The results show that bFGF increases clone mineralization (11%), but not in PDL cell population. The cell clones that mineralized only in the presence of bFGF have higher CAP binding ability and lower ALP expression compared with other mineralized clone cells. CONCLUSION: bFGF enhances mineralizing expression of PDL clone. The clones that mineralized only with bFGF treatment are different cell types from the bFGF-undependent mineralized clones.

Adult↗