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PubMed1995

Vasectomy in the rat--effects on mineral metabolism, with emphasis on renal tissue minerals and occurrence of urinary stones.

An increased stone frequency and hypotestosteronemia after vasectomy were reported and suggest development of some disturbance of homeostasis of minerals and hormones. The objective of the present study in the rat was to assess the effects of vasectomy (n = 14) and vasovasostomy (n = 12) on gonadal state, intestinal absorption of minerals and mineral concentrations in serum, urine and 3 renal tissue regions. Sham-operated animals (n = 12) served as controls. Seven months after surgery the combined results show that vasectomy induced a significant decrease in gonadal weight, but not in serum and urinary testosterone; serum magnesium was decreased (p = 0.014 versus controls) and phosphaturia was increased (p = 0.025), whereas serum calcium, parathyroid hormone and urinary cyclic AMP were unchanged. Also, after vasectomy there was a significant accumulation of phosphorus, calcium and magnesium in renal papillae and additionally of phosphorus in the renal cortical and medullary region; oxalate was unchanged. Renal stones containing calcium phosphate were found in 2 vasectomized rats, but in none of the vasovasostomized ones. In contrast, in vasovasostomized rats, mineral accumulation in renal tissues was abolished, and the associated concentration of serum free testosterone was 3 times higher (p = 0.018) than in control rats. It was concluded that vasectomy in the rat 1) may not be neutral to gonadal function in terms of gonadal weight; 2) disturbs the homeostasis of magnesium, calcium and phosphorus at the level of the kidney; and 3) induces mild hypomagnesemia and marked hyperphosphaturia in the presence of normal parathyroid gland function. It is suggested that these sequelae of vasectomy and vasovasostomy may be traced back to a disturbance of autonomous nerve tone.

Animals↗
PubMed1978

Histologic findings in the tracheobronchial tree of uranium miners and non-miners with lung cancer.

The remaining tissue of the tracheobronchial tree from 210 men who died from lung cancer was studied to compare the histologic alterations leading to further sites of primary cancer. These men were uranium miners matched with nonminers for age and smoking habits. In the examination of a total of 28,928 cross-sections carcinoma in situ was found in 96% of the miners and in 92% of the nonminers. The number of slides from miners showing degree 2 or 3 atypia in areas of carcinoma in situ was about double the number found from the nonminers. Although the difference was not statistically significant, 32% of the miners had at least one section showing early primary invasive carcinoma compared with 22% of the nonminers. The data indicate that the synergistic effect of the exposure to uranium dust along with cigarette smoking increases the risk of lung cancer and that in addition to a main tumor mass, other sites of tissue alterations leading to tumor development are frequently already present in the lung.

Adult↗
PubMed1994

Bone mineral density, sex steroids, and mineral metabolism in premenopausal smokers.

Smoking is related to decreased bone mass and increased risk of osteoporotic fractures. However, the harmful effects of smoking on bone have not been well characterized. The purpose of this study was to assess the repercussions of smoking on bone mass in premenopausal women, and the relationship between these effects and parameters of mineral metabolism and hormone profile. We measured bone mineral density (BMD) in 101 premenopausal women (47 smokers, 54 nonsmokers) with dual-energy X-ray absorptiometry (DeXA) of the proximal femur and lumbar spine. In a subgroup of the sample (16 smokers, 15 nonsmokers) we measured biochemical indicators of mineral metabolism and hormone profile. BMD in the femoral neck, Ward's triangle, and the intertrochanter region was significantly lower in smokers (P < 0.05) than in nonsmokers. Concentrations of sex hormone-binding globulin were higher, and free testosterone index (FTI) was lower (P < 0.05) in smokers. We found no significant differences between the groups in parameters of mineral metabolism. Concentrations of dehydroepiandrosterone sulfate and free testosterone index were directly correlated with values of BMD in different sites. Our findings show that smoking by premenopausal women is associated with decreased BMD and characteristic changes in the hormone profile.

Absorptiometry, Photon↗
PubMed1992

Bone mineral density and abstention-induced changes in bone and mineral metabolism in noncirrhotic male alcoholics.

BACKGROUND AND PURPOSE: Abuse of alcohol may derange bone metabolism and cause osteoporosis. Due to confounding factors associated with alcohol abuse, however, the effect of alcohol itself on bone loss remains obscure. The influence of alcohol intake on bone and mineral metabolism is rather well known, but how the metabolism normalizes during withdrawal has rarely been investigated. The aims of the present study were to evaluate the alcohol-induced changes of bone and mineral metabolism and their recovery during abstention, and to reassess any possible link between alcohol abuse and osteoporosis. PATIENTS AND METHODS: We studied 27 non-cirrhotic male alcoholics hospitalized for 2 weeks for withdrawal. For comparison, three groups of control subjects were examined. Serum and urinary parameters of bone and mineral metabolism as well as intestinal absorption of calcium were determined at the beginning and end of the treatment period. Bone mineral density (BMD) was measured by dual-energy x-ray absorptiometry at four axial sites (lumbar spine, femoral neck, Ward's triangle, trochanter). RESULTS: On admission, bone formation in the alcoholics was reduced as reflected by decreased serum levels of osteocalcin (-28%; p < 0.05) and procollagen I carboxyterminal propeptide (-17%; p < 0.05). Both parameters normalized within 2 weeks of abstention (p < 0.0001 and p < 0.01, respectively). Urinary hydroxyproline, a parameter of bone resorption, was at the control level on admission and increased slightly during abstention (p < 0.05). Serum ionized calcium increased by 3% (p < 0.0001) during withdrawal. Concomitantly, serum free fatty acids (FFA) decreased by 38% (p < 0.001), and there existed an inverse correlation (r = -0.50, p < 0.05) between changes in ionized calcium and FFA. Serum levels of intact parathyroid hormone and vitamin D metabolites were similar in patients and controls throughout the whole observation period. Intestinal absorption of calcium measured by stable strontium was 37% higher in alcoholics than in controls (p < 0.001); it decreased to nearly normal toward the end of the treatment period. Mean axial BMD did not differ between patients and controls at any of the four measurement sites. However, BMD decreased parallel with duration of drinking history in the alcoholics at all axial sites (p < 0.05 to < 0.01, analysis of covariance with age and weight as covariates). CONCLUSIONS: Decreased bone formation, which is uncoupled from ongoing bone resorption, recovers completely during 2 weeks of abstention. In the absence of confounding factors, the central BMD is normal in noncirrhotic male alcoholics, although the negative effect of alcohol on BMD is evident when duration of excessive drinking is taken into account.

Absorptiometry, Photon↗
PubMed1987

Effect of alkaline-phosphatase inhibition by 1-p-bromotetramisole on the formation of trichloroacetic acid-[32P]-insoluble phosphate from inorganic [32P]-phosphate and [32P]-pyrophosphate in non-mineralizing and mineralizing hamster molar tooth-germs in vitro.

In culture, 1-p-bromotetramisole (pBTM), a specific inhibitor of alkaline phosphatase, significantly inhibited the formation of trichloroacetic acid (TCA)-insoluble [32P]-phosphate from inorganic [32P]-phosphate in the proliferating non-mineralizing second (M2) maxillary molar germs but had no effect in the actively mineralizing first (M1) germs. Addition of 10(-5) M inorganic pyrophosphate in the culture medium with a [32P]-phosphate label increased the inhibition of the formation of TCA-insoluble [32P]-phosphate in the M2. pBTM almost completely inhibited the formation of TCA-insoluble [32P]-phosphate from inorganic [32P]-pyrophosphate in the non-mineralizing M2. In the actively mineralizing M1, the compound significantly inhibited but did not abolish the formation of TCA-insoluble phosphate. These results confirm earlier biochemical findings that alkaline phosphatase possesses a pyrophosphatase activity probably related to the turnover of phosphorylated macromolecules necessary for cell differentiation and proliferation.

Alkaline Phosphatase↗
PubMed1992

The influence of high dietary protein, energy and mineral intake on deficient young camel (Camelus dromedarius)--II. Changes in mineral status.

1. Mangrove Avicennia marina is poor in some trace elements such as copper, zinc and manganese. In a trial we used 32 young camels divided into four groups. 2. Groups 1 and 3 were supplemented with copper and zinc in drinking water after 1 month of mangrove feeding. 3. Groups 2 and 3 received concentrate rich in protein and energy. The supplementation was stopped after 2 months. 4. All the camels were deficient in trace elements at the beginning of mineral supplementation. 5. The plasma concentration of copper increased significantly up to normal levels (less than 70 micrograms/100 ml) in energy protein supplemented groups, but the quantity supplied (100 mg of copper sulphate/day) was not sufficient to maintain this level after the end of supplementation. 6. The original zinc deficiency was too severe to observe a significant effect of the mineral supplementation. 7. Calcium, magnesium and phosphorus levels were improved during the supplementation period in protein-energy supplemented groups. 8. A high interaction between mineral absorption and quality of the diet was observed. A well-balanced diet seems essential to avoid deficient mineral status.

Animals↗
PubMed2004

Bone mineral density and total body bone mineral content in 18- to 22-year-old women.

One hundred sixty-four (164) healthy, young Caucasian women enrolled as midshipmen at the United States Naval Academy with no known disease or bone injury were followed for 3.6 years. Change in bone mineral density (BMD) of the hip, lumbar spine and distal tibia, and total body bone mineral content (TBMC) was measured by dual energy X-ray absorptiometry (DXA). Bone mineral density and TBMC of these women were measured within 2 months (60 +/- 4 days) of entering the Academy and annually. Over the study period, hip BMD increased 2.26% (P < 0.001), lumbar spine BMD increased 3.27% (P < 0.001) and distal tibia BMD increased 5.2% (P < 0.001). Total body bone mineral content showed a 5.25% (P < 0.001) increase during the study period. In this group of young women, gain in BMD and TBMC continued until age 22. These results suggest that bone mass may accrue in certain groups of women beyond age 22. The significance of this increase in bone mass during early adulthood on risk for osteoporotic fractures in later life and its impact on exercise-related bone injuries are unknown and warrant further examination.

Adolescent↗
PubMed1995

Mineral bioavailability and bone mineral contents in pigs given calcium carbonate postprandially.

We have further investigated the "meal effect" on mineral bioavailability in pigs by mineral balance studies and measurements of bone ash contents and bending moment. A group of seven pigs (CAA) was given all its dietary Ca as CaCO3 5 h after the first daily meal for 8 weeks. The control group of seven pigs received CaCO3 in the meal. Both groups were given normal P within the meals. Ca and P absorption and retention were evaluated by a 10-day balance trial. Several bones were collected at slaughter to determine bone ash, Ca, and P contents and bending moment (three-point bending test). Ingesting Ca after the meal did not affect Ca bioavailability or phosphorus absorption, but did reduce P retention, which in turn decreased the bone scores. Osteopenia, indicated by decreased total mineral contents of bones (and decreased ash:bone volume ratio), was associated with elevated plasma osteocalcin in the CAA group. Thus, CaCO3 need not be incorporated into a meal for high Ca absorption, provided that Ca is given after a meal, but simultaneous intakes of Ca and P are required for the best mineral retention.

Absorption↗
PubMed2000

Factors affecting newborn bone mineral content: in utero effects on newborn bone mineralization.

Several factors have been found recently to have a significant impact on newborn bone mineral content (BMC) and developing fetal bone. Recently we showed that maternal vitamin D deficiency may affect fetal bone mineralization. Korean winter-born newborn infants had extremely low serum 25-hydroxyvitamin D (25-OHD), high serum cross-linked carboxy-terminal telopeptide of type I collagen (ICTP; a bone resorption marker), and markedly lower (8 %) total body BMC than summer-born newborn infants. Infant total body BMC was positively correlated with cord serum 25-OHD and inversely correlated with ICTP, which was also negatively correlated with vitamin D status. In three separate studies on North American neonates we found markedly lower (8-12 %) BMC in summer newborn infants compared with winter newborn infants, the opposite of the findings for Korean neonates. The major reason for the conflicting BMC results might be the markedly different maternal vitamin D status of the North American and Korean subjects. Recently, we found evidence of decreased bone formation rates in infants who were small-for-gestational age (SGA) compared with infants who were appropriate-for-gestational age; we reported reduced BMC, cord serum osteocalcin (a marker of bone formation) and 1,25-dihydroxyvitamin D (the active metabolite of vitamin D), but no alterations in indices of fetal bone collagen metabolism. In theory, reduced utero-placental blood flow in SGA infants may result in reduced transplacental mineral supply and reduced fetal bone formation. Infants of diabetic mothers (IDM) have low BMC at birth, and infant BMC correlated inversely with poor control of diabetes in the mother, specifically first trimester maternal mean capillary blood glucose concentration, implying that factors early in pregnancy might have an effect on fetal BMC. The low BMC in IDM may be related to the decreased transplacental mineral transfer. Cord serum ICTP concentrations were higher in IDM than in control subjects, implying increased intrauterine bone resorption. BMC is consistently increased with increasing body weight and length in infants. Race and gender differences in BMC appear in early life, but not at birth. Ethanol consumption and smoking by the mother during pregnancy affect fetal skeletal development.

Animals↗
PubMed1994

Investigation of the relative contributions of cigarette smoking and mineral dust exposure to activation of circulating phagocytes, alterations in plasma concentrations of vitamin C, vitamin E, and beta carotene, and pulmonary dysfunction in South African gold miners.

OBJECTIVES: To determine the relative effects of cigarette smoking and mineral dust exposure on numbers and activity of circulating phagocytes, plasma nutritional antioxidant state, and pulmonary function in South African gold miners. METHODS: Pulmonary function was assessed spirometrically, whereas reactive oxidant generation by circulating phagocytes, and plasma concentrations of the nutritional antioxidative nutrients vitamin C and vitamin E and beta carotene were measured with chemiluminescence, spectrophotometry, or high performance liquid chromatography respectively. RESULTS: Cigarette smoking, but not mineral dust exposure, was associated with increased numbers and pro-oxidative activity of circulating neutrophils and monocytes, decreased plasma concentrations of vitamin C, and pulmonary dysfunction. DISCUSSION: In this study group occupational exposure to mineral dust has not been found to promote increases in the numbers or reactivity of circulating phagocytes or to be a significant cause of pulmonary dysfunction, the changes found being due primarily to cigarette smoking.

Adult↗
PubMed1987

Risk of lung cancer among iron ore miners: a proportional mortality study of 1,075 deceased miners in Lorraine, France.

A proportional mortality study of 1,075 iron ore miners in Lorraine, France, who died between 1960 and 1976 showed a significant excess of lung cancer mortality (proportionate mortality ratio = 2.25). Moreover, proportionate lung cancer mortality increased with the duration of work underground (proportionate mortality ratio = 4.24 for subjects who worked underground for more than 30 years) and was higher among pneumoconiotic (siderotic) miners (proportionate mortality ratio = 3.85) than among nonpneumoconiotic miners. These results were confirmed by a case-control study nested in the mortality study. Smoking habits could not be estimated retrospectively with sufficient accuracy to be taken into account. Although the proportion of smokers among contemporary iron ore miners is larger than in the French male population, occupational factors may also play a role; radiation exposure can be ruled out because there is no detectable radioactivity in the Lorraine mines, but dust exposure may be considered as an etiologic factor owing to the relationship between siderosis and lung cancer.

Adult↗
PubMed1987

Soluble minerals in chemical evolution. II. Characterization of the adsorption of 5'-AMP and 5'-CMP on a variety of soluble mineral salts.

The adsorption of 5'-AMP and 5'-CMP was studied in saturated solutions of several soluble mineral salts (NaCl, Na2SO4, MgCl2 X 6H2O, MgSO4 X 7H2O, CaCl2 X 2H2O, CaSO4 X 2H2O, SrCl2 X 6H2O, SrSO4, and ZnSO4 X 7H2O) as a function of pH, ionic strength, and surface area of the solid salt. The adsorption shows a pH dependence; this can be correlated with the charge on the nucleotide molecule which is determined by the state of protonation of the N-1 nitrogen of 5'-AMP or N-3 nitrogen of 5'-CMP and the phosphate oxygens. The adsorption which results from the binding between the nucleotide molecule and the salt surface is proposed as being due to electrostatic forces. It was concluded that the adsorption was reversible in nature. The adsorption shows a strong dependence upon ionic strength and decreases with increasing ionic strength. Surface area is shown to be an important factor in evaluating and comparing the magnitude of adsorption of nucleotides onto various mineral salts. The implications of the results of the study are discussed in terms of the importance of soluble mineral salts as adsorption sites in the characterization of the adsorption reactions of an adsorbed template in biogeochemical cycles.

Adenosine Monophosphate↗
PubMed1987

Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust.

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.

Aged↗
PubMedDate not supplied

Lung mineral fibers of former miners and millers from Thetford-Mines and asbestos regions: a comparative study of fiber concentration and dimension.

Fiber dimension and concentration may vary substantially between two necropsy populations of former chrysotile miners and millers of Thetford-Mines and Asbestos regions. This possibility could explain, at least in part, the higher incidence of respiratory diseases among workers from Thetford-Mines than among workers from the Asbestos region. The authors used a transmission electron microscope, equipped with an x-ray energy-dispersive spectrometer, to analyze lung mineral fibers of 86 subjects from the two mining regions and to classify fiber sizes into three categories. The most consistent difference was the higher concentration of tremolite in lung tissues of workers from Thetford-Mines, compared with workers from the Asbestos region. Amosite and crocidolite were also detected in lung tissues of several workers from the Asbestos region. No consistent and biologically important difference was found for fiber dimension; therefore, fiber dimension does not seem to be a factor that accounts for the difference in incidence of respiratory diseases between the two groups. The greater incidence of respiratory diseases among workers of Thetford-Mines can be explained by the fact that they had greater exposure to fibers than did workers at the Asbestos region. Among the mineral fibers studied, retention of tremolite fibers was most apparent.

Aged↗
PubMed2006

Radiogenic argon distribution within a mineral grain: implications for dating of hydrothermal mineral-forming event in Sludyanka complex, Siberia, Russia.

Usually, in age-determination procedures, the experimenter is interested in the mean concentrations of parent and daughter substances. However, the structure of a solution of the Fick's diffusion equation enables one to specify a procedure, allowing, through macroscopic experiments, one to determine the distribution of radiogenic argon (as well as any of other isotopes) within a mineral grain. Argon, influenced in the geological past by a metamorphic event, has a half-sinusoidal distribution, whereas argon preserved in geological time has a rectangular distribution. The ratio of the quantity of argon of the first type to the total argon is called an alpha-factor. It is believed that this coefficient can be of great interest for geochronological studies, being a symptom of virtual Ar losses and the time instant, at which they happened. A laboratory procedure and a mathematical algorithm to determine the alpha-factor are developed. As an example, a determination of the alpha-factor on a vein-phlogopite from the well-studied Sludyanka deposit, Southern Baikal, Siberia, Russia, is described. Rb-Sr isochron age on phlogopite-calcite-apatite paragenetic assemblage yielded 460+/-7 Ma and is constrained by U-Pb zircon ages of 471+/-1 and 447+/-2 Ma, respectively, on an emplacement of early syenites and monzonites and later 'post-phlogopitic' pegmatites [E.B. Salnikova, S.A. Sergeev, A.B. Kotov, S.Z. Yakovleva, R.H. Steiger, L.Z. Reznitskiy, E.P. Vasil'ev. U-Pb zircon dating of granulite metamorphism in the Sludyanskiy complex, Eastern Siberia. Gondwana Res., 1, 195-205 (1998). L.Z. Reznitskii, G.P. Sandimirova, Y.A. Pakhol'chenko, S.V. Kuznetsova. The Rb-Sr age of phlogopite deposits in Sludyanka, southern Baikal region. Dokl. Earth Sci., 367, 711-713 (1999). L.Z. Reznitskii, A.B. Kotov, E.B. Salnikova, E.P. Vasil'ev, S.Z. Yakovleva, V.P. Kovach, A.M. Fedoseenko. The age and time span of the origin of phlogopite and lazurite deposits in the Southwestern Baikal area: U-Pb geochronology. Petrology, 8, 66-76 (2000).]. In this study, the phlogopite gave an apparent K-Ar age of 365.6+/-10.4 Ma which has no geological meaning. The alpha-factor of 0.27 was derived from a laboratory kinetic experiment. The age determined by the rectangularly distributed argon corresponded to alphax0.129 nmm3/g (total radiogenic argon in the sample)=94.17 nmm3/g, and an age of approximately 274 Ma (e.g. a period without any argon losses). Here, at the first sight, we deal with common argon losses not conjugated with any geological event, because after 447 Ma only lower temperature (in a range of 50-300 degrees C) hydrothermal processes were recorded. A paragenetic phlogopite-bearing vein mineral, hyalophane, having a disturbed Rb-Sr isotopic system, however, yielded 40Ar/39Ar subplateau age of 271+/-2 Ma [V.V. Ivanenko, M.I. Karpenko, M.A. Litsarev. Age of the Sludyanka phlogopite deposits (in Russian; data of the 39Ar-40Ar method). In Geological Series 5, pp. 92-98, Izvestiya Akademii Nauk SSSR, Moskva (1990).], marking similar timing of the K-Ar isotopic system closure. This indicates that K-Ar isotopic system in the phlogopite was not closed (or was partially reset) long after its crystallisation and closing of the Rb-Sr system, in spite of the fact that the crystal was not affected by processes having temperatures above the accepted closure temperatures for micas. There seems to have acted an exchange mechanism of OH-groups between surrounding fluid and hydrocrystal structure. Thus the argon loss did not occur, spontaneously, but argon particles seem to have been captured and carried to the mineral surface by vacancies formed during displacements of OH-groups.

Argon↗
PubMed1989

Bone mineralization and mineral homeostasis in very low-birth-weight infants fed either human milk or fortified human milk.

Abnormalities in bone mineral metabolism are frequently found in very low-birth-weight infants, especially if fed breast milk. To assess the efficacy of a breast-milk fortifier in the feeding of these very small infants, very low-birth-weight babies (between 1,000 g-1,500 g at birth) were randomly assigned to one of two groups on day 4 of life. The fortified group received the fortifier mixed in equal proportions with their own mother's milk, while the breast-milk group received only their own mother's milk. All infants received an oral vitamin D supplement of 750 IU/day. The study was continued until the infants weighed 1,800 g, at which stage breast feeding was encouraged. Thirty infants in the breast-milk group and 29 in the fortified group completed the study. Infants in the fortified group had significantly lower alkaline phosphatase values, a greater bone mineral content (BMC) and BMC/bone width ratio, and lower urinary calcium excretion than the breast-milk group at a weight of 1,800 g. At follow-up study 3 months after delivery, when most of the infants in both groups had been breast fed for at least 6 weeks, the breast-milk group's biochemical and BMC abnormalities were almost totally corrected and were now similar to those of the fortified group. Thus, the addition of the fortifier to breast milk during the first 4-6 weeks of life decreased the biochemical evidence of abnormal bone mineral homeostasis and increased BMC in very low-birth-weight infants. By 3 months of age, however, the breast-milk group had almost totally corrected its abnormalities.

Body Weight↗
PubMed1987

Bisphosphonate whole body retention test: relations to bone mineralization rate, renal function and bone mineral content in osteoporosis and metabolic bone disorders.

The bisphosphonate whole body retention test (WBR) has been used to estimate bone mineralization rate (bone turnover). Bisphosphonates given i.v. are taken up by bone or excreted in urine. The aim of the present investigation was to test the efficacy of WBR in estimating bone mineralization rate (m) and to evaluate the influence of renal function (Clcr) and bone mass (forearm bone mineral content; BMC) on WBR. The 24-h retention of 3.7 MBq 99mTc-HMBP (1-hydroxymethylene-1,1-bisphosphonate) (Osteoscan) given i.v. was measured by a medium sensitive whole body counter in thirty-one patients with hyperparathyroidism (n = 14), hyperthyroidism (n = 8) or hypothyroidism (n = 9) (group 1) and in seventy-six females with postmenopausal spinal crush fracture osteoporosis (group 2). In the same individuals m was calculated from a 7-day 47Ca-kinetic study using the expanding calcium pool model. Multiple regression analysis of WBR vs. m and Clcr in group 1 disclosed that WBR correlated positively to m [rp = 0.49, P less than 0.01 (rp = partial correlation coefficient)] and inversely to Clcr (rp = -0.44, P less than 0.02). Inclusion of BMC in the analysis did not reveal any significant partial correlation between WBR and BMC (rp = -0.33, 0.05 less than P less than 0.10). In group 2 WBR correlated inversely to Clcr (rp = -0.48, P less than 0.001) but showed no significant relation to m (rp = 0.10, NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Mineral balance and whole body bone mineral content in very low-birth-weight infants.

Fat and mineral metabolic balance studies were performed in 25 normal very low-birth-weight infants (< or = 1500 g at birth) fed either pooled pasteurized human milk supplemented with calcium, phosphorus and magnesium, or a preterm formula. Calcium, phosphorus and magnesium intake were similar in both groups and averaged 100 mg/kg/day, 72 mg/kg/day and 8 mg/kg/day, respectively. Calcium and phosphorus retention was higher in the subjects fed fortified human milk than in those receiving a preterm formula (65 +/- 14 and 62 +/- 9 mg/kg/day versus 55 +/- 12 and 47 +/- 7 mg/kg/day respectively). The difference was only significant for phosphorus. Magnesium retention was similar in the two groups and averaged 3 mg/kg/day. Fat intake and absorption was significantly higher in the preterm formula fed group than in the one fed fortified human milk (5.5 +/- 0.4 g/kg/day and 88 +/- 4% versus 4.2 +/- 1 g/kg/day, 79 +/- 6% respectively). Assessment of the whole body bone mineral content by dual energy X-ray absorptiometry was performed at 3 and 6 months of age in another group of 25 low-birth-weight infants fed either fortified human milk or a preterm formula. Whole body bone mineral content (BMCt) was low (43.3 +/- 30.8 g of hydroxyapatite) at 3 months of age (theoretical term) compared to normal full-term newborns at birth. There was no significant influence of the diet. At 6 months of age, BMCt reached 168.6 +/- 36.6 g, a value similar to that of full-term newborns, with no significant difference between the two regimen groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Density↗