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PubMed1984

A quantitative microradiographic study of mineral content of supragingival and subgingival dental calculus.

This study was undertaken to determine the distribution and concentration of mineral in supragingival and subgingival dental calculus. Extracted incisors and premolars with attached dental calculus were used. After fixation the specimens were dehydrated and embedded in methylmethacrylate and 100-micrometers-thick ground sections were made. Microradiographs were produced and the mineral content in the sections was determined photometrically, using an aluminum step-wedge as a reference system. The distribution of the mineral varied considerably within the specimens and between different specimens. Supragingival calculus appeared heterogeneous and often stratified, containing areas that seemed to be non-calcified. The average mineral content was 37% by volume. By contrast subgingival calculus appeared homogeneously calcified, with an average mineral content of 58%. No differences in mineral content between surface areas and portions close to the tooth were seen. This indicates that once the calculus is formed no changes occur in the mineral content, i.e. no maturation occurs with age. Local variations in mineral content within the calculus might be explained by periodic differences in the fluid environment of the microbial plaque.

Absorption↗
PubMed2003

Effect of bone mineral content on the tensile properties of cortical bone: experiments and theory.

The effect of mineral volume fraction on the tensile mechanical properties of cortical bone tissue is investigated by theoretical and experimental means. The mineral content of plexiform, bovine bone was lowered by 18% and 29% by immersion in fluoride solutions for 3 days and 12 days, respectively. The elastic modulus, yield strength and ultimate strength of bone tissue decreased, while the ultimate strain increased with a decrease in mineral content. The mechanical behavior of bone tissue was modeled by using a micromechanical shear lag theory consisting of overlapped mineral platelets reinforcing the organic matrix. The decrease in yield stress, by the 0.002 offset method, of the fluoride treated bones were matched in the theoretical curves by lowering the shear yield stress of the organic matrix. The failure criterion used was based on failure stresses determined from a failure envelope (Mohr's circle), which was constructed using experimental data. It was found that the model predictions of elastic modulus got worse with a decrease in mineral content (being 7.9%, 17.2% and 33.0% higher for the control, 3-day and 12-day fluoride-treated bones). As a result, the developed theory could not fully predict the yield strain of bones with lowered mineral content, being 12.9% and 21.7% lower than the experimental values. The predicted ultimate stresses of the bone tissues with lower mineral contents were within +/- 10% of the experimental values while the ultimate strains were 12.7% and 26.3% lower than the experimental values. Although the model developed in this study did not take into account the presence of hierarchical structures, voids, orientation of collagen molecules and micro cracks, it still indicated that the mechanical properties of the organic matrix depend on bone mineral content.

Animals↗
PubMed1985

Effects of chemical speciation on the mineralization of organic compounds by microorganisms.

The mineralization of 1.0 to 100 ng each of four complexing compounds-oxalate, citrate, nitrilotriacetate (NTA), and EDTA-per ml was tested in media prepared in accordance with equilibrium calculations by a computer program so that the H, Ca, Mg, Fe, or Al complex (chemical species) was predominant. Sewage microorganisms mineralized calcium citrate more rapidly than iron, aluminum, or hydrogen citrate, and magnesium citrate was degraded slowest. Aluminum, hydrogen, and iron oxalates were mineralized more rapidly than calcium oxalate, and magnesium oxalate was decomposed slowest. Sewage microorganisms mineralized calcium NTA but not aluminum, magnesium, hydrogen, or iron NTA or any of the EDTA complexes. Pseudomonas sp. mineralized calcium and iron citrates but had no activity on hydrogen, aluminum, or magnesium citrate. Pseudomonas pseudoalcaligenes mineralized calcium, iron, hydrogen, and aluminum citrates but had little activity on magnesium citrate. Pseudomonas alcaligenes used calcium, iron, hydrogen, and aluminum oxalates readily, but it used magnesium oxalate at a slower rate. Listeria sp. destroyed calcium NTA but had no effect on hydrogen, iron, or magnesium NTA. Increasing the Ca concentration in the medium enhanced the breakdown of NTA by Listeria sp. The different activities of the bacterial isolates were not a result of the toxicity of the complexes or the lack of availability of a nutrient element. NTA mineralization was not enhanced by the addition of Ca to Beebe Lake water, but it was enhanced when Ca and an NTA-degrading inoculum were added to water from an oligotrophic lake. The data show that chemical speciation influences the mineralization of organic compounds by naturally occurring microbial communities and by individual bacterial populations.

Journal Article↗
PubMed1986

Kinetics of mineralization of organic compounds at low concentrations in soil.

The kinetics of mineralization of 14C-labeled phenol and aniline were measured at initial concentrations ranging from 0.32 to 5,000 ng and 0.30 ng to 500 micrograms/g of soil, respectively. Mineralization of phenol at concentrations less than or equal to 32 ng/g of soil and of aniline at all concentrations began immediately, and the curves for the evolution of labeled CO2 were biphasic. The patterns of mineralization of 4.0 ng of 2,4-dichlorophenol per g of soil and 20 ng of nitrilotriacetic acid per g of soil were similar to the patterns for phenol and aniline. The patterns of mineralization of 1.0 to 100 ng of p-nitrophenol and 6.0 ng of benzylamine per g of soil were also biphasic but after a short apparent lag period. The curves of CO2 evolution from higher concentrations of phenol and p-nitrophenol had increasing apparent lag phases and were S-shaped or linear. Cumulative plots of the percentage of substrate converted to CO2 were fit by nonlinear regression to first-order, integrated Monod, logistic, logarithmic, zero-order, three-half-order, and two-compartment models. None of the models of the Monod family provided the curve of best fit to any of the patterns of mineralization. The linear growth form of the three-half-order model provided the best fit for the mineralization of p-nitrophenol, with the exception of the lowest concentrations, and of benzylamine. The two-compartment model provided the best fit for the mineralization of concentrations of phenol below 100 ng/g, of several concentrations of aniline, and of nitrilotriacetic acid. It is concluded that models derived from the Monod equation, including the first-order model, do not adequately describe the kinetics of mineralization of low concentrations of chemicals added to soil.

Aniline Compounds↗
PubMed1990

Supplemental substrate enhancement of 2,4-dinitrophenol mineralization by a bacterial consortium.

A Janthinobacterium sp. and an actinomycete, both capable of mineralizing 2,4-dinitrophenol (DNP), were used to construct a consortium to mineralize DNP in nonaxenic bench-scale sequencing batch reactors (SBRs). Average K(m) values for DNP mineralization by pure cultures of the Janthinobacterium sp. and the actinomycete were 0.01 and 0.13 mug/ml, respectively, and the average maximum specific growth rate (mu(max)) values for them were 0.06 and 0.23/h, respectively. In the presence of NH(4)Cl, nitrite accumulation in pure culture experiments and in the SBRs was stoichiometric to initial DNP concentration and the addition of nitrogen enhanced DNP mineralization in the SBRs. Mineralization of 10 mug of DNP per ml was further enhanced in SBRs by the addition of glucose at concentrations of 100 and 500 mug/ml but not at 10 mug/ml. Possible mechanisms for this enhanced DNP mineralization in SBRs were suggested by kinetic analyses and biomass measurements. Average mu(max) values for DNP mineralization in the presence of 0, 10, 100, and 500 mug of glucose per ml were 0.33, 0.13, 0.42, and 0.59/h, respectively. In addition, there was greater standing biomass in reactors amended with glucose. At steady-state operation, all SBRs contained heterogeneous microbial communities but only one organism, an actinomycete, that was capable of mineralizing DNP. This research demonstrates the usefulness of supplemental substrates for enhancing the degradation of toxic chemicals in bioreactors that contain heterogeneous microbial communities.

Journal Article↗
PubMed2002

Rhodanobacter sp. strain BPC1 in a benzo[a]pyrene-mineralizing bacterial consortium.

A bacterial consortium which rapidly mineralizes benzo[a]pyrene when it is grown on a high-boiling-point diesel fuel distillate (HBD) was recovered from soil and maintained for approximately 3 years. Previous studies have shown that mobilization of benzo[a]pyrene into the supernatant liquid precedes mineralization of this compound (R. Kanaly, R. Bartha, K. Watanabe, and S. Harayama, Appl. Environ. Microbiol. 66:4205-4211, 2000). In the present study, we found that sterilized supernatant liquid filtrate (SSLF) obtained from the growing consortium stimulated mineralization of benzo[a]pyrene when it was readministered to a consortium inoculum without HBD. Following this observation, eight bacterial strains were isolated from the consortium, and SSLF of each of them was assayed for the ability to stimulate benzo[a]pyrene mineralization by the original consortium. The SSLF obtained from one strain, designated BPC1, most vigorously stimulated benzo[a]pyrene mineralization by the original consortium; its effect was more than twofold greater than the effect of the SSLF obtained from the original consortium. A 16S rRNA gene sequence analysis and biochemical tests identified strain BPC1 as a member of the genus Rhodanobacter, whose type strain, Rhodanobacter lindaniclasticus RP5557, which was isolated for its ability to grow on the pesticide lindane, is not extant. Strain BPC1 could not grow on lindane, benzo[a]pyrene, simple hydrocarbons, and HBD in pure culture. In contrast, a competitive PCR assay indicated that strain BPC1 grew in the consortium fed only HBD and benzo[a]pyrene. This growth of BPC1 was concomitant with growth of the total bacterial consortium and preceded the initiation of benzo[a]pyrene mineralization. These results suggest that strain BPC1 has a specialized niche in the benzo[a]pyrene-mineralizing consortium; namely, it grows on metabolites produced by fellow members and contributes to benzo[a]pyrene mineralization by increasing the bioavailability of this compound.

Bacteria↗
PubMed1995

A controlled study of bone mineral density in patients with inflammatory bowel disease.

To assess the prevalence of and risk factors for low bone mineral density in inflammatory bowel disease (IBD), 152 IBD patients and 73 healthy controls were studied. Sixty seven patients had ulcerative colitis, 78 had Crohn's disease (52 of them (66.7%) had ileal disease), and seven had indeterminate colitis. Bone mineral density values (g/cm2) measured by dual energy x ray absorbtiometry at the spine (L2-L4), the femoral neck, Ward's triangle, and the trochanter were 1.177, 0.948, 0.850, and 0.838 in the patients and 1.228 (p = 0.034), 1.001 (p = 0.009), 0.889 (NS), and 0.888 (p = 0.012) in the control group, respectively. The type or extent of the disease or previous small bowel resection did not have any significant effect on the bone mineral density values. There was a weak, but statistically significant negative correlation between bone mineral density and the total lifetime corticosteroid dose (in the lumbar spine r = -0.164, p = 0.04, the femoral neck r = -0.185, p = 0.02, Ward's triangle r = -0.167, p = 0.04, and the trochanter r = -0.237, p = 0.003). The patients whose lifetime corticosteroid dose (prednisone/prednisolone) was more than 10 g had especially low bone mineral density (p < 0.05 compared with the groups with no or less than 5 g of corticosteroid). The patients who had never taken peroral corticosteroids did not have decreased bone mineral density. In conclusion, IBD patients have significantly lower bone mineral density values than healthy controls, but the difference is not so great as has been reported previously. Low bone mineral density values in these patients are related to high lifetime corticosteroid doses.

Adrenal Cortex Hormones↗
PubMed1997

Relationship of serum elastin peptide level to single breath transfer factor for carbon monoxide in French coal miners.

BACKGROUND: Clinical and epidemiological studies have given discordant results on the usefulness of the level of circulating elastin peptide (EP), a potential marker of both elastin destruction (a key phenomenon in pulmonary emphysema) and neosynthesis, for assessing structural changes in the lung extracellular matrix. The aim of the present study was to explore the relationship between levels of EP and forced expiratory volume in one second (FEV1) and single breath transfer factor for carbon monoxide (TLCO and KCO) in coal miners. METHODS: The study population comprised 227 working coal miners aged 34-50 years consisting of 75 miners heavily exposed to underground coal dust with pulmonary radiographs classified as 0/1 or 1/0 by the International Labour Office classification, 75 exposed miners with radiographs classified as normal (0/0), and 77 miners slightly exposed to coal dust with normal radiographs. The subjects answered a standardised questionnaire and performed spirometric tests and a carbon monoxide (CO) transfer test. RESULTS: No association was observed between EP levels and % predicted FEV1 (or FEV1/FVC). The level of EP increased significantly with decreased % predicted TLCO (r = -0.20). Miners in the lowest % predicted KCO quintile had higher EP levels than the rest (3.28 (1.37) vs 2.47 (1.16)). A significantly lower EP level was observed in miners with radiographs classified as 1/0 or 0/1, especially in those with round opacities, compared with miners with a normal radiograph, and in current smokers compared with the rest. CONCLUSIONS: The results of this study suggest that the level of EP may reflect some remodelling activity in emphysema and lung fibrosis.

Adult↗
PubMed1993

Correlates and determinants of bone mineral content and density in healthy adolescent girls.

The relationships between whole-body and lumbar spine bone mineral content and density, and measures of chronologic age, body composition, physical activity, cardiorespiratory and strength fitness, gynecologic attributes, sexual maturity, and endocrine status were studied in 35 healthy menarcheal girls (14-18 years of age). Body mass (0.464 < r < 0.704), growth hormone (-0.34 < r < -0.42), and one-repetition maximum double-leg press strength (0.343 < r < 0.467) were significantly (p < 0.05) correlated with each of the five bone mineral measures. Multiple regression analysis indicated that body mass accounted for the largest significant proportion of the explained variance (30.2-68.2%) in each of the five bone mineral measures. Age at first menses accounted for a smaller but still significant proportion of the variance in whole-body bone mineral content (4.05%) and lumbar spine bone mineral content (8.06%). Growth hormone entered the regression model as an important predictor of whole-body bone mineral content, accounting for 3.51% of the explained variance in this variable. Age, cardiorespiratory fitness, level of habitual activity, and strength did not contribute significantly to the explained variance in any of the bone mineral measures. Body mass appears to be the single most important determinant of bone mineral among females during this developmental period.

Adolescent↗
PubMedDate not supplied

Increased bone volume and bone mineral content in xylitol-fed aged rats.

BACKGROUND: Our previous studies have shown that dietary xylitol supplementation protects against the loss of bone mineral after ovariectomy. The ovariectomy-induced decrease in trabecular bone volume is significantly retarded by dietary xylitol. OBJECTIVE: To study whether dietary xylitol can protect against bone loss also during aging, a long-term experimental study was performed with rats. METHODS: Twenty-four male Sprague-Dawley rats were divided into two groups. The rats in the control group were fed a basal RM1 diet, while the rats in the experimental group were continuously fed the same diet supplemented with 10% (w/w) xylitol. The rats were killed after 20 months. Their tibiae were used for the analyses of bone density and trabecular bone volume, and their femurs were used for the scanning analyses with peripheral quantitative computed tomography (pQCT). RESULTS: The tibial density of the xylitol-fed aged group (1.73 +/- 0.14 g/mm(3)) was significantly greater than that of the aged group without xylitol (1.56 +/- 0.14 g/ mm(3)). The trabecular bone volume of the xylitol-fed rats was 21.2 +/- 4.0%. It was significantly greater than that of the rats not receiving xylitol (9.3 +/- 4.3%). The pQCT-measured cortical bone mineral density and the pQTC-measured cortical bone mineral content of the femoral diaphysis were significantly greater in the xylitol-fed group than in the control group. The trabecular bone mineral density and the trabecular bone mineral content of the femoral distal metaphysis were also significantly greater in the xylitol-fed group than in the non-xylitol group. The total bone mineral density and the total bone mineral content of the femoral neck in the xylitol-fed aged group significantly exceeded those in the aged group without xylitol supplementation. CONCLUSIONS: A continuous moderate dietary xylitol supplementation leads to increased bone volume and increased bone mineral content in the long bones of aged rats. This indicates a xylitol-induced protection against aging-related osteoporotic changes.

Aging↗
PubMed2005

Role of matrix Gla protein in parathyroid hormone inhibition of osteoblast mineralization.

Parathyroid hormone (PTH) exerts biphasic effects on bone, dependent on the frequency and dose of administration. The catabolic actions of PTH on bone have been associated with continuous treatment, an increase in osteoblast-mediated resorption of bone via osteoclast activation, and inhibition of osteoblast activity and mineralization. Downregulation of differentiation markers and inhibition of mineralization by PTH have been reported in primary calvarial explants and osteoblast cell lines. Using MC3T3-E1 osteoblast-like cells, we have shown that matrix Gla protein (MGP) can be induced by PTH, and that this induction may explain the PTH-mediated inhibition of osteoblast biomineralization. MGP is a known inhibitor of mineralization, and mice deficient in Mgp show severe vascular calcification and premature bone mineralization. This review discusses the role of MGP in mineralization, comparing bone and vascular mineralization. In addition to MGP, the regulation and possible role of osteopontin, another known regulator of osteoblast mineralization, in PTH-mediated regulation of bone and vascular mineralization is discussed.

Animals↗
PubMed1980

Effects of 1 alpha-OH-D3 on bone mineral content in the forearm of chronic hemodialyzed patients.

The bone mineral content in the forearm of 99 male and 62 female patients who had never been treated with vitamin D on hemodialysis was measured to elucidate the relationship between bone mineral content and duration of hemodialysis. We found that reduction in bone mineral content related to the duration of hemodialysis in both sexes. 1--2 microgram/day of 1 alpha-OH-D3 was administered to 35 hemodialysis patients for 2 years. Bone mineral content in the forearm of both patient groups treated with and without 1 alpha-OH-D3 was measured every 3 months. Although bone mineral content in the forearm of the hemodialysis patients decreased, serum Ca, serum-ionized Ca, and serum phosphate levels increased and serum ALK-Pase and serum immunoreactive PTH decreased significantly after administration of 1 alpha-OH-D3. When bone mineral content in the forearm of patients treated with 1 alpha-OH-D3 was compared with that of untreated patients, the loss of bone mineral content in patients treated with 1 alpha-OH-D3 was less than that of the untreated group. In addition to uremic metabolic derangements, intermittently repeated humoral derangement on hemodialysis seems to cause loss of bone mineral content.

Adolescent↗
PubMed1973

Inhibition of bone matrix formation, mineralization, and resorption in thyroparathyroidectomized rats.

In previous work we found that vitamin D-deficient and also calcium-deficient rats developed hypocalcemia and an impairment of bone formation and mineralization. The present study of thyroparathyroidectomized (TPTX) rats was undertaken to determine the effect of hypocalcemia without secondary hyperparathyroidism. TPTX rats fed a normal diet developed hypocalcemia and hyperphosphatemia in association with impairment of osteoblastic bone matrix formation and of mineralization of newly formed matrix. The serum calcium x phosphorus product was not decreased. The decreased formation was largely due to a reduction in matrix apposition indicating decreased synthetic activity of individual ostcoblasts. In contrast to the above results, when TPTX rats were fed a high-calcium diet to prevent hypocalcemia, no impairment of either formation or mineralization was found. From the results of these two experiments, it is reasonably certain that hypocalcemia was responsible for the inhibition of formation and mineralization. Moreover, based on the magnitude of the changes in serum calcium and bone parameters in TPTX rats, hypocalcemia could have accounted for the inhibition of formation and mineralization in calcium-deficient as well as vitamin D-deficient rats. In TPTX rats the mineralization defect was manifested by decreases in both the rate of osteoid maturation (indicating a delayed onset of mineralization) and the rate of mineralization. A strong correlation (r = 0.95, P < 0.001) was observed between these two rates suggesting a tight coupling of these two aspects of mineralization.TPTX rats also had lower bone resorption rates and higher serum phosphorus levels than sham-operated animals when the normal calcium diet was fed but not when the high-calcium diet was fed. Thus the inhibition of bone resorption in TPTX rats was at least partially prevented by correction of hyperphosphatemia. This is consistent with previous work showing an inverse relationship between serum phosphorus and bone resorption. Accordingly, the depression of bone resorption in TPTX rats was probably due to hyperphosphatemia as well as to hypoparathyroidism.

Animals↗
PubMed1993

The role of phospholipase A2 in interleukin-1 alpha-mediated inhibition of mineralization of the osteoid formed by fetal rat calvaria cells in vitro.

Interleukin-1 (IL-1) may be an important mediator of bone remodeling, since it is a potent stimulator of bone resorption and has biphasic effects on bone formation. Continuous exposure of fetal rat calvaria (RC) cells to IL-1 alpha or IL-1 beta results in a dose-dependent inhibition of both bone nodule formation and mineralization of the organic matrix. In this study, the effects of recombinant human IL-1 alpha on the mineralization process were examined by the addition of IL-1 alpha late in the culture period, after osteoid nodules had formed and when they were induced to mineralize by the addition of organic phosphate. By means of a quantitative 45calcium radiolabeling assay, it was shown that short-duration exposures of fully-formed bone nodules to IL-1 alpha also inhibited mineralization, and that the duration of treatment directly correlated with the degree of inhibition. Because our earlier studies had demonstrated that IL-1 stimulated the release of PLA2 and PGE2 from RC cells, the effects of PLA2 and of inhibition of PGE2 synthesis on mineralization were investigated. Exogenous Naja naja group I PLA2 had little effect on the mineralization of bone nodules; however, Crotalus adamanteus group II PLA2 inhibited mineralization at concentrations similar to those found in the media from IL-1 alpha-treated cultures. Although PLA2 is thought to stimulate PGE2 synthesis by releasing arachidonic acid from membrane phospholipids, PGE2 release by RC cells accounted for only part of the IL-1 alpha-mediated inhibition, suggesting the presence of other mechanisms of exogenous PLA2 action in inhibiting mineralization.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed2005

Bone mineral and collagen quality in iliac crest biopsies of patients given teriparatide: new results from the fracture prevention trial.

CONTEXT: Evidence suggests that both bone mineral density and bone quality should be taken into account when assessing bone strength and fracture risk. Bone quality is a multifactor entity, of which bone architecture and material properties are two important components. Matrix mineralization, hydroxyapatite characteristics, and collagen cross-link ratio are key determinants of material properties. Fourier transform infrared imaging (FTIRI) yields data on these characteristics from bone sections. OBJECTIVE: We sought to determine collagen cross-link ratios and matrix mineralization of bone from patients randomized to teriparatide [recombinant human PTH (1-34)] treatment using FTIRI. DESIGN: The Fracture Prevention Trial was randomized, double blind, and placebo-controlled. SETTING: The trial was conducted at global clinical research centers. PATIENTS: Patients consisted of postmenopausal women with osteoporosis. INTERVENTIONS: Patients were randomized to receive daily sc injections of placebo (n = 12) or 20 microg (n = 13) or 40 microg (n = 13) teriparatide. Biopsies were obtained after 12 months of treatment or at the end of treatment (range, 19-24 months for end of treatment paired biopsies). MAIN OUTCOME MEASURES: Biopsies were analyzed by FTIRI to determine the matrix mineralization (mineral to matrix), mineral crystallinity, and collagen cross-link ratio (pyridinoline/dehydrodihydroxylysinonorleucine) with a spatial resolution of approximately 6.3 microm. RESULTS: Patients administered teriparatide 20 and 40 microg/d exhibited significantly lower matrix mineralization, mineral crystallinity, and collagen cross-link ratio when compared with placebo. CONCLUSIONS: These findings indicate that the bone-forming effect of teriparatide results in bone with a molecular profile reminiscent of younger bone.

Aged↗
PubMed1990

Negative correlation between the change in bone mineral density and serum osteocalcin in patients with hyperthyroidism.

To assess the changes in bone mineral density and osteoblastic activity in patients with hyperthyroidism and to investigate the relationship between those changes, we measured bone mineral density and serum osteocalcin in 109 patients with Graves' disease, comprising 75 untreated patients and 34 patients under treatment, and 200 normal controls. The degree of change in bone mineral density was quantified with Z transformation, in which we used means and SDs of bone mineral densities obtained in the process of age- and sex-matched 1:1 pairing developed by ourselves. Bone mineral density was low in female patients with hyperthyroidism in the spine, femur neck, trochanter, and Ward's triangle, but was not low in male patients. Serum osteocalcin was elevated in patients with untreated Graves' disease and correlated negatively with the Z values of bone mineral densities of the spine, femur neck, and trochanter. In conclusion, indices of osteoblastic activity were elevated in patients with hyperthyroidism, probably secondary to a thyroid hormone-induced increase in bone resorption which resulted in reduced bone mineral density. Quantification of the change in bone mineral density by using the parameters derived in the process of age- and sex-matched pairing seems to be an efficient method for statistical analyses.

Adolescent↗
PubMed2006

[Relationship of changes in radius bone mineral density during seven years in working women around thirty years old with lifestyle, body measurement data and laboratory data].

OBJECTIVES: A longitudinal study was conducted to investigate the relationships of the change in radius bone mineral density for seven years with lifestyle, body measurement data and laboratory data. METHODS: The subjects of this study were 191 female employees working in an LSI manufacturing factory in Japan. Bone mineral density was measured on the radius of their nondominant side using DXA (dual energy X-ray absorptiometry) in 1995 and 2002. Other medical examinations were performed at the same time. Multiple regression analysis was also performed with the change in radius bone mineral density as the dependent variable. RESULTS: As a result of the multiple regression analysis, a significant positive correlation was observed between the change in body mass index (BMI) and the change in bone mineral density among the subjects aged 30 years and over and those under 30 years. A significant positive correlation was observed between daily milk intake and the change in bone mineral density among those aged under 30 years. A significant negative correlation was observed between daily alcohol intake and the change in bone mineral density among those aged under 30 years, and also between parity and the change in bone mineral density among those aged 30 years and over. CONCLUSIONS: BMI, parity, daily milk intake and daily alcohol intake are considered as significant factors that contribute to a change in bone mineral density. It is necessary that the recommended timing for medical examination be set according to age, and that a well-balanced guidance be provided from young adulthood.

Adult↗
PubMed1993

Monitoring genotoxic exposure in uranium miners.

Recent data from deep uranium mines in Czechoslovakia indicated that in addition to radon daughter products, miners are also exposed to chemical mutagens. Mycotoxins were identified as a possible source of mutagenicity present in the mines. Various methods of biomonitoring were used to examine three groups of miners from different uranium mines. Cytogenetic analysis of peripheral lymphocytes, unscheduled DNA synthesis (UDS) in lymphocytes, and lipid peroxidation (LPO) in both plasma and lymphocytes were studied on 66 exposed miners and 56 controls. Throat swabs were taken from 116 miners and 78 controls. Significantly increased numbers of aberrant cells were found in all groups of miners, as well as decreased UDS values in lymphocytes and increased LPO plasma levels in comparison to controls. Molds were detected in throat swabs from 27% of miners, and 58% of these molds were embryotoxic. Only 5% of the control samples contained molds and none of them was embryotoxic. The following mycotoxins were isolated from miners' throat swab samples: rugulosin, sterigmatocystin, mycophenolic acid, brevianamid A, citreoviridin, citrinin, penicilic acid, and secalonic acid. These data suggest that mycotoxins are a genotoxic factor affecting uranium miners.

Adult↗