Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “MINERALS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1985

Intrinsic mineral labeling of edible plants: methods and uses.

The fate of minerals can be conveniently studied through intrinsic labeling techniques. The mineral of interest is biologically incorporated into the food in a form that can be distinguished analytically from the natural form of the element. Radiolabels have traditionally been used to study such problems as the uptake of minerals by plants, the gross and subcellular mineral distribution in plant tissues, the form and associations of the deposited mineral, and the bioavailability of minerals to animals and humans. The use of stable (nonradioactive) isotopes as a label offers the potential of safely studying bioavailability of minerals from individual foods in human population groups of all ages using foods processed in normal food handling and processing facilities.

Agriculture↗
PubMed1995

[Contents and deposition of major minerals in tissues and in the whole bodies of growing young bulls German Simmental breed].

54 bulls of the German Simmental breed were fed either on a high energy level (maize silage ad libitum and 1.8 kg concentrate) or on a low energy level (maize silage restrictively and 1.0 kg concentrate). In dependence on feeding intensity a mean daily weight gain of 870 or 1210 g was obtained. Animals were slaughtered with a live mass of 200 kg, 350 kg, 500 kg, 575 kg and 650 kg. Empty body was divided into 13 cuts and afterwards separated into lean, bone and adipose tissues and tendons. Major mineral element content was determined in these tissues as well as in the noncarcass parts. In the lean tissue the mean content (200 kg) of 0.3 g calcium, 10 g phosphorus, 1 g magnesium, 2.3 g sodium and 14.8 g potassium/kg dry matter decreased slightly with rising live mass (200-650 kg). The contents of major mineral elements were much higher in bone tissue. For the fattening period from 200 to 650 kg of live mass mean contents of 151.5 g calcium, 71.3 g phosphorus, 3.2 g magnesium, 5.1 g sodium and 1.1 g potassium per kg DM were analysed. Mineral element content of bone tissue increased with rising live mass as well as animals on low feeding intensity showed a higher mineral content than on high energy level. In all, major mineral element content in fat tissue was very low. In noncarcass parts head and legs calcium and phosphorus had analogous to bone tissue the highest concentration. Hide showed a high content of sodium, whereas organs and digestive tract had a high content of potassium and phosphorus. Total mass of major mineral elements in the different tissues increased above all in the fattening period of 200 to 350 kg. In carcass as well as in empty body, mass of calcium and phosphorus was much higher than magnesium, sodium and potassium. Also animals on low feeding intensity showed a higher mass of major mineral elements in carcass and empty body than animals on high energy feeding intensity. The intensively fed bulls had a mean deposition of 12.7 g calcium, 6.9 g phosphorus, 0.37 g magnesium, 1.2 g sodium and 2.1 g potassium per 1000 g of empty body weight gain, whereas restrictively fed bulls deposited in average 15.0 g calcium, 7.8 g phosphorus, 0.4 g magnesium, 1.2 g sodium and 2.4 g potassium per 1000 g of empty body weight gain.

Animals↗
PubMed1997

Effect of mineral oil on porcine urothelium.

Mineral oil has been used to facilitate ureteral stone extraction and to treat selected patients with infected residual urine. The purpose of this study was to evaluate the effect of mineral oil on the urothelium. Twelve adult female farm pigs underwent bilateral ureteral catheter placement under general endotracheal anesthesia. Retrograde pyelograms were performed and the ureteral diameters measured. Using a randomization protocol, six animals underwent injection of 10 mL of normal saline into one ureteral catheter and 50 mL of normal saline instillation into the bladder. In the remaining six animals, 10 mL of mineral oil was injected into one ureteral catheter and 50 mL of mineral oil into the bladder. The instillation was maintained for 30 minutes, and then the catheters were removed. One week later, under general endotracheal anesthesia, cystoscopy and retrograde pyelography were performed to measure the diameter of the ureters, and the animals were euthanized. The bladder, ureters, and kidneys were harvested for macroscopic and histopathologic evaluation. There was no significant difference in the diameter of the ureters injected with normal saline, the uninjected ureters, or the mineral oil-injected ureters. The bladders, ureters, and kidneys were grossly normal in all animals. No significant histopathologic changes were noted in the ureteral or bladder urothelium or the renal parenchyma in the animals injected with mineral oil. In conclusion, the instillation of mineral oil within the urinary tract does not have any significant long-term functional or histopathologic effect on the urothelium.

Animals↗
PubMed2005

Mineral particles of varying composition induce differential chemokine release from epithelial lung cells: importance of physico-chemical characteristics.

Presently, little is known about the potential health effects of mineral particles other than asbestos and quartz. In this study, a human epithelial lung cell line (A549), primary human small airway epithelial cells (SAECs) and primary rat type 2 (T2) cells were exposed to stone quarry particles of two size fractions (<10 and <2.5 microm) from nine different rock samples. The ability to induce the release of chemokines from lung cells was investigated and compared with the particles' mineral and element composition and the amount of soluble elements. The stone particles induced the release of only low levels of interleukin (IL)-8 from A549 cells. In contrast, some of the other particles induced the release of high levels of macrophage inflammatory protein (MIP)-2 from T2 cells, and high levels of IL-8 from SAECs. Differences in particle surface area could account for differences in activity between the <10 and <2.5 microm fractions of six out of the nine rock samples. For two samples the <2.5 microm fraction was most active and for one sample the <10 microm fraction was most active. Content of the mineral plagioclase displayed a strong, negative correlation with the potential to induce MIP-2, whereas the mineral pyroxene was positively correlated with MIP-2 induction. However, neither plagioclase nor pyroxene content was sufficient to explain differences in bioactivity between the particles. No statistically significant correlation was found between the amounts of total or soluble elements and MIP-2 release. In conclusion, the results suggest that mineral particles with a high content of plagioclase have a low potential to induce a pro-inflammatory response. However, a particular mineral or element responsible for eliciting strong increases in chemokine release could not be identified. Thus, at present it appears that analysing mineral and element content is insufficient to predict stone particle bioactivity, and that biological testing is a necessity.

Animals↗
PubMed2001

Short-term orlistat treatment does not affect mineral balance and bone turnover in obese men.

Orlistat is a gastrointestinal lipase inhibitor that is used to reduce dietary fat absorption and to enhance weight loss in subjects consuming a hypocaloric diet. To assess whether orlistat has an effect on the metabolism of six minerals, a 21-d, double-blind, randomized, parallel-group, placebo-controlled mineral balance study was conducted in obese (body mass index > 30 kg/m(2)) men. Subjects consumed a hypocaloric diet with a constant daily mineral content and received daily oral treatment with orlistat (120 mg three times daily) (n = 14) or placebo (three times daily) (n = 14) for 21 d. After a 14-d equilibration period, calcium, phosphorus, magnesium, iron, copper and zinc balances were assessed for d 15-21. In addition, the effect of diet and orlistat treatment on bone metabolism was estimated from measurement of biomarkers of bone formation and bone resorption. Serum and urine electrolytes were also measured at baseline and at the end of treatment. Orlistat inhibited fat absorption by approximately 33% (P < 0.05). There were no significant differences in mineral apparent absorption, urinary mineral loss or mineral balance between the orlistat and placebo groups. Markers of bone turnover and serum and urine electrolytes did not differ between the orlistat and placebo groups. Orlistat was well tolerated; adverse events were of mild or moderate intensity, and the majority of these events were unrelated or remotely related to study treatment. In obese men consuming a hypocaloric diet, the administration of orlistat had no significant effect on the balance of six selected minerals. In addition, biomarkers of bone turnover, as well as serum and urine electrolytes, were not affected by orlistat treatment.

Adult↗
PubMed1990

Regional distribution of mineral and matrix in the femurs of rats flown on Cosmos 1887 biosatellite.

We combined biochemical measurements with novel techniques for image analysis in the rat femur to characterize the location and nature of the defect in mineralization known to occur in growing animals after spaceflight. Concentrations of mineral and osteocalcin were low in the distal half of the diaphysis and concentrations of collagen were low with evidence of increased synthesis in the proximal half of the diaphysis of the flight bones. X-ray microtomography provided semiquantitative data in computer-generated sections of whole wet bone that indicated a longitudinal gradient of decreasing mineralization toward the distal diaphysis, similar to the chemistry results. Analysis of embedded sections by backscattered electrons in a scanning electron microscope revealed distinct patterns of mineral distribution in the proximal, central, and distal regions of the diaphysis and also showed a net reduction in mineral levels toward the distal shaft. Increases in mineral density to higher fractions in controls were less in the flight bones at all three levels, with the most distal cross-sectional area most affected. The combined results from these novel techniques identified the areas of femoral diaphysis most vulnerable to the mineralization defect associated with spaceflight and/or the stress of landing.

Animals↗
PubMedDate not supplied

Vertebral mineral determination by quantitative computed tomography (QCT): accuracy of single and dual energy measurements.

Quantitative CT (QCT) studies of trabecular vertebral bone tissue have been carried out in vitro on a GE CT/T 9800 scanner. Results of both single energy (SE) 80 kVp and dual energy (DE) 80/140 kVp QCT data are compared with chemical mineral analysis to determine accuracy. We examined 62 vertebral specimens, from 28 cadavers (19 male and 9 female with an age range of 19-93 years, mean = 60.4). Averaging the results of all vertebral bodies of the same individual for SEQCT versus ashweight, we found a correlation coefficient (r) of 0.94 (p less than 0.0001), a standard error of the estimate (SEE) of 12.2 mg/cm3 (calibrated to K2HPO4), with a coefficient of variation (CV) of 13.2% and an average underestimation of bone mineral content of 18.7 mg/cm3. The corresponding DEQCT results were r = 0.98 (p less than 0.0001), SEE = 7.4 mg/cm3, CV = 7.0%, and an average underestimation of 4.9 mg/cm3. The SE and DE results are correlated with r = 0.98 (p less than 0.0001), SEE = 8.0 mg/cm3, and CV = 8.7%. From our SEQCT data and the results of the chemical analysis of bone mineral and fat content we calculated a fat sensitivity of 7.7 mg/cm3 K2HPO4 per 100 mg/cm3 fat change for our scanner. Using an average fat variability of 87.5 mg/cm3, this leads to a fat-related uncertainty for the normative SEQCT data of 6.7 mg/cm3, which is far lower than the normal biological variation of 29.4 mg/cm3. Using tabulated normative data on fat content versus age and versus mineral content of 188 vertebral specimens from five collaborating centers, we derived a correction algorithm for QCT measurement that reduces our average underestimation to 0.88 mg/cm3 with an SEE of 12.1 mg/cm3. Hence, this correction procedure can be used to estimate the fat corrected absolute mineral density for research purposes or for scanners with high fat sensitivity. For the GE CT/T 9800 scanner, with a relatively low fat to mineral sensitivity at 80 kVp, the correction procedure is generally not recommended for clinical studies since it minimizes the average fat induced error but does not reduce the residual, partially fat related uncertainty. Finally, since the fat related uncertainty is small compared to biological variation, the correlation is high between SEQCT and DEQCT, and the radiation dose is lower and the precision higher for SEQCT, we suggest that most clinical diagnostic studies using the GE CT/T 9800 scanner for bone mineral determination employ SEQCT at 80 kVp.

Adult↗
PubMed1994

Mineral distribution in the enamel of teeth with amelogenesis imperfecta as determined by quantitative microradiography.

The aim of the present investigation was to determine the mineral distribution in the enamel of teeth with amelogenesis imperfecta (AI) by quantitative microradiography. A further aim was to correlate the findings to clinical manifestations and inheritance patterns for AI. Included in the study were a total of 29 teeth with AI, 28 primary and one permanent, and seven unaffected teeth, five primary and two permanent. Quantitative microradiography was applied to sagittally ground sections, 70-90 microns, of the teeth. The mineral content of the enamel, expressed as percentage by volume, was lower in most of the teeth with AI than in the unaffected teeth. The largest range for the mineral distribution was found in the enamel of the variants clinically characterized by hypomineralization. These teeth showed a mineral distribution pattern that reflected an extremely low mineral content in the bulk of the enamel. In the AI teeth clinically characterized by hypoplasia, the mineral distribution pattern was similar to that of the unaffected teeth, although with larger local variations in mineral content. Apart from the teeth connected with X-linked inheritance, no differences were found among teeth with similar clinical variants connected with different inheritance patterns.

Amelogenesis Imperfecta↗
PubMed2006

Differential adsorption of occluded and nonoccluded insect-pathogenic viruses to soil-forming minerals.

Soil represents the principal environmental reservoir of many insect-pathogenic viruses. We compared the adsorption and infectivity of one occluded and two nonoccluded viruses, Helicoverpa armigera single nucleopolyhedrovirus (HaSNPV) (Baculoviridae), Cricket paralysis virus (CrPV) (Dicistroviridae), and Invertebrate iridescent virus 6 (IIV-6) (Iridoviridae), respectively, in mixtures with a selection of soil-forming minerals. The relative infective titers of HaSNPV and CrPV were unchanged or slightly reduced in the presence of different minerals compared to their titers in the absence of the mineral. In contrast, the infective titer of IIV-6 varied according to the mineral being tested. In adsorption studies, over 98% of HaSNPV occlusion bodies were adsorbed by all the minerals, and a particularly high affinity was observed with ferric oxide, attapulgite, and kaolinite. In contrast, the adsorption of CrPV and IIV-6 differed markedly with mineral type, with low affinity to bentonites and high affinity to ferric oxide and kaolinite. We conclude that interactions between soil-forming minerals and insect viruses appear to be most important in nucleopolyhedroviruses, followed by invertebrate iridescent viruses, and least important in CrPV, which may reflect the ecology of these pathogens. Moreover, soils with a high content of iron oxides or kaolinite would likely represent highly effective reservoirs for insect-pathogenic viruses.

Adsorption↗
PubMed1987

Explanations for the acclimation period preceding the mineralization of organic chemicals in aquatic environments.

A study was conducted of possible reasons for acclimation of microbial communities to the mineralization of organic compounds in lake water and sewage. The acclimation period for the mineralization of 2 ng of p-nitrophenol (PNP) or 2,4-dichlorophenoxyacetic acid per ml of sewage was eliminated when the sewage was incubated for 9 or 16 days, respectively, with no added substrate. The acclimation period for the mineralization of 2 ng but not 200 ng or 2 micrograms of PNP per ml was eliminated when the compound was added to lake water that had been first incubated in the laboratory. Mineralization of PNP by Flavobacterium sp. was detected within 7 h at concentrations of 20 ng/ml to 2 micrograms/ml but only after 25 h at 2 ng/ml. PNP-utilizing organisms began to multiply logarithmically after 1 day in lake water amended with 2 micrograms of PNP per ml, but substrate disappearance was only detected at 8 days, at which time the numbers were approaching 10(5) cells per ml. The addition of inorganic nutrients reduced the length of the acclimation period from 6 to 3 days in sewage and from 6 days to 1 day in lake water. The prior degradation of natural organic materials in the sewage and lake water had no effect on the acclimation period for the mineralization of PNP, and naturally occurring inhibitors that might delay the mineralization were not present. The length of the acclimation phase for the mineralization of 2 ng of PNP per ml was shortened when the protozoa in sewage were suppressed by eucaryotic inhibitors, but it was unaffected or increased if the inhibitors were added to lake water.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1992

Mineralization of glucose and lignocellulose by four arctic freshwater sediments in response to nutrient enrichment.

Microbial biomass and activity were examined in four different arctic sediments: littoral lake sediment and profundal lake sediment from Toolik Lake, Alaska, thaw pond sediment, and eroding river bank peat. The thaw pond sediment had the largest viable microbial biomass, while the profundal sediment had the smallest. Rates of glucose or acetate incorporation into lipids, glucose mineralization, and lignocellulose mineralization (all normalized per unit of biomass) were highest in the river peat sample, however. The kinetics of glucose mineralization in the profundal sediment were very different from those in the other three samples: although the initial rate of mineralization was five times lower than that in the peat and two times lower than that in the littoral and thaw pond sediments, the maximum amount of 14CO2 evolved from [14C]glucose eventually equaled that in the peat and exceeded that in the littoral and thaw pond sediments by 2.0 and 3.5 times, respectively. Carex aquatilis [14C-cellulose]- and [14C-lignin]lignocellulose mineralization rates in the profundal sediment equaled or exceeded those in the littoral sediment after 16 and 46 days, but the pattern of nutrient limitation differed: the profundal sediment was the only one sampled that exhibited nitrogen limitation, while the other three sediments appeared to be limited primarily by phosphorus. The addition of nitrogen and phosphorus together had no cumulative effects on lignocellulose mineralization. When the rates of mineralization or incorporation of glucose are compared with those of lignocellulose, the results of this study indicate that profundal sediment communities may be better able to utilize the more recalcitrant substrates relative to the labile substrates than microbial communities from sediments rich in detritus and standing macrophytes.

Acetates↗
PubMed1994

Aerobic and anaerobic degradation and mineralization of 14C-chitin by water column and sediment inocula of the York River estuary, Virginia.

Potential rates of chitin degradation (Cd) and mineralization (Cm) by estuarine water and sediment bacteria were measured as a function of inoculum source, temperature, and oxygen condition. In the water column inoculum, 88 to 93% of the particulate chitin was mineralized to CO2 with no apparent lag between degradation and mineralization. No measurable dissolved pool of radiolabel was found in the water column. For the sediment inocula, 70 to 90% of the chitin was degraded while only 55 to 65% was mineralized to CO2. 14C label recoveries in the dissolved pool were 19 to 21% for sand, 17 to 24% in aerobic mud, and 12 to 21% for the anaerobic mud. This uncoupling between degradation and mineralization occurred in all sediment inocula. More than 98% of the initial 14C-chitin was recovered in the three measured fractions. The highest Cd and Cm values, 30 and 27% day-1, occurred in the water column inoculum at 25 degrees C. The lowest Cd and Cm values were found in the aerobic and anaerobic mud inocula incubated at 15 degrees C. Significant differences in Cd and Cm values among water column and sediment inocula as well as between temperature treatments were evident. An increased incubation temperature resulted in shorter lag times before the onset of chitinoclastic bacterial growth, degradation, and mineralization and resulted in apparent Q10 values of 1.1 for water and 1.3 to 2.1 for sediment inocula. It is clear that chitin degradation and mineralization occur rapidly in the estuary and that water column bacteria may be more important in this process than previously acknowledged.

Aerobiosis↗
PubMed1989

Local bone mineral response to brief exercise that stresses the skeleton.

OBJECTIVE: To compare grip strength and bone mineral content in the forearm in women and to test the effects on bone mineral content of short periods of exercise that stresses the skeleton. DESIGN: Assessment of both wrists in 69 volunteers and of the non-fractured wrist in 30 patients followed by an exercise regimen entailing squeezing a tennis ball as hard as possible for 30 seconds each day for six weeks. SETTING: Old people's homes and outpatient departments of Hammersmith and Northampton general hospitals. PATIENTS: 99 Women, of whom 69 were volunteers and 30 had a fractured forearm. MAIN OUTCOME MEASURE: Grip strength and bone mineral content after six weeks and at six months after the exercises had stopped. RESULTS: The bone mineral content of the women's forearms was measured with a densitometer and the grip strength with a semi-inflated bag connected to an anaeroid barometer. Measurements before exercise showed that the two variables correlated closely, irrespective of age, and that there were significant differences in both between the dominant and non-dominant arms of the volunteers. After six weeks of exercise there was a mean increase in grip strength of 14.5% (95% confidence interval 9.9 to 19.2%) and in bone mineral content of 3.4% (1.4 to 5.3%) in the stressed forearms of the 77 women who attended for examination. After six months without exercise the improvements in the 33 women who attended for follow up had reversed. Women who had had a fractured forearm (n = 13), however, had continued to gain grip strength and bone mineral content in the arm that had not been injured. CONCLUSIONS: Grip strength in the forearm is a good indicator of bone mineral content. Both variables may be increased by brief periods of stressful exercise. If this principle can be applied to the whole skeleton it may provide a means of reversing osteoporosis.

Bone and Bones↗
PubMed1986

Single photon absorptiometry for the measurement of bone mineral content in horses.

A safe, non-invasive method for the accurate measurement of bone mineral content in the third metacarpal bone of the horse is described. The technique involves scanning the bone with a single photon beam from an Americium-241 source. Data were obtained from the excised metacarpal bones from both forelimbs of 50 normal and seven lame horses. Measurements were made in vivo on eight normal and seven lame horses and on one experimental horse with osteopenia induced by partial weightlessness in a flotation tank. In the normal horses bone mineral content altered with age, particularly in the first six months of life. There were also differences according to the site of scanning on the metacarpus. The contribution of the splint bones to the total bone mineral content was less than 2 per cent distal to the mid-point of the metacarpus, but in the proximal shaft it increased to 12 per cent. No significant differences were noted either between right and left limbs, or between male and female animals. A reduction in bone mineral content was demonstrated in the affected leg of horses with chronic lameness and with osteopenia induced by weightlessness. The bone mineral content (g/cm) correlated well with the ash content (mg/100 mg dry bone weight), the specific gravity and the apparent transverse velocity of ultrasound (m/sec) through the bone. A measure of bone mineral density (g/cm3) was calculated from the bone mineral content and cross sectional area of the bone to overcome the individual differences in size of the metacarpus.

Age Factors↗
PubMed1993

Mineral induction in vivo by dentine proteins.

The mineral-inductive capacity of polyanionic noncollagenous proteins, isolated from calcified tissues, has earlier been demonstrated in vitro. These macromolecules possess this capacity, provided that they are immobilized on a solid support, whereas in solution they inhibit crystal mineral induction and growth. The present study demonstrates this capacity also in vivo. Phosphoprotein, proteoglycan and gamma-carboxyglutamate-containing protein (Gla-protein) of the osteocalcin type were covalently coupled to AH-Sepharose beads, and these were implanted subcutaneously in minipigs for periods between 3 and 24 weeks. Similarly, demineralized rat incisor dentine was implanted for 3 weeks, as was predentine dissected from dentinogenically active bovine incisors. The results were analyzed by scanning electron microscopy and energy dispersive X-ray analysis. Dentine proteoglycan and phosphoprotein coupled to beads were found to be inducers of calcium/phosphate-containing mineral, whereas the efficacy of Gla-protein was negligible. Dissected predentine did not induce any mineral, but demineralized dentine preparations, still containing some noncollagenous anionic components, were found to induce mineral. The results indicate that macromolecules such as proteoglycan and phosphoprotein may be responsible for mineral induction during mineralization of calcified tissues. The results further imply that such molecules may be of importance for the remineralization of dentine in conjunction with the caries process.

Animals↗
PubMed1976

Age and activity effects on rate of bone mineral loss.

It has been postulated that the rate of mineral loss in postmenopausal women remains constant with aging and that the decreased activities of daily living associated with aging contribute to mineral loss. These hypothese were examined by measuring the bone mineral content at the midshaft of the radius with the photon absorption technique. The estimated rate of loss was calculated in a cross-sectional study as the regression coefficient of bone mineral content vs. age and in a longitudinal study as the regression coefficient of bone mineral content vs. time. In the cross-sectional study, Group A, which consisted of 264 women aged 50-72 yr, had an estimated rate of loss of -0.0114 +/- 0.0014 (SE) g/cm per yr. Group B, which consisted of 266 women aged 73-96 yr, had an estimated rate of loss of -0.0055 +/- 0.0017 g/cm per yr. In the longitudinal study, Group C consisted of 33 women aged 51-65 yr who were followed for an average of 4.5 yr with a mean number of 16 visits per subject; they were found to have a mean rate of loss of -0.00990 +/- 0.00107 g/cm per yr. Group D consisted of 38 women aged 70-91 yr who were followed for an average of 3.8 yr with a mean number of 31 visits per subjects; they were found to have a mean rate of loss of -0.00020 +/- 0.00236 g/cm per yr. The estimated and directly measured rates of loss were more rapid in the younger groups than in the older groups (A vs. B, P less than 0.001; C vs. D, P less than 0.001). These data demonstrate that the mean rate of mineral loss is not constant with aging and that in elderly subjects it is significantly slower than that of the earlier postmenopausal years. Since the elderly women were the less active, these findings suggest that factors other than decreased physical activity are more important in determining the rates of mineral loss.

Activities of Daily Living↗
PubMed1996

Enamel mineral composition of normal and cystic fibrosis transgenic mice.

The ability of ameloblasts and the enamel organ to control the influx of ions into the developing enamel is of considerable interest. The development of transgenic mice lacking a cAMP-regulated chloride channel, the cystic fibrosis transmembrane conductance regulator (CFTR), provides a model that may prove valuable for the study of ion regulation in developing teeth. The purpose of this investigation was to characterize the mineral content of normal and CF mice. Five homozygous and five heterozygous adult mice having the CFTR knockout transgene were evaluated. The mice were killed with CO2 and their mandibular incisors removed, embedded in methacrylate, and sectioned, and enamel particles from the incisal region were then dissected for analysis. Each particle was analyzed for its calcium, phosphorus, and magnesium content. The normal mice had a mean mineral content of 80.5%, in contrast to the CF mice, that had markedly hypomineralized enamel (mean = 51.5%). The calcium/phosphorus ratios were similar for both groups of mice and were compatible with the enamel consisting primarily of hydroxyapatite mineral. The enamel magnesium content was significantly elevated in the CF mice (mean = 3560 ppm) compared with the normal mice (mean = 2280 ppm). Normal mouse enamel was highly mineralized, while the CF mouse enamel mineral content was significantly reduced and had an elevated level of magnesium. The altered mineral content of CF mouse enamel indicates that CFTR could play an important role in ion regulation and consequently mineralization of mouse enamel.

Ameloblasts↗
PubMed2005

Association between occupational exposure to mineral oil and rheumatoid arthritis: results from the Swedish EIRA case-control study.

The aim of the present study was to investigate the association between exposure to mineral oil and the risk of developing rheumatoid arthritis (RA), and in addition to perform a separate analysis on the major subphenotypes for the disease; namely, rheumatoid factor (RF)-positive RA, RF-negative RA, anticitrulline-positive RA and anticitrulline-negative RA, respectively. A population-based case-control study of incident cases of RA was performed among the population aged 18-70 years in a defined area of Sweden during May 1996-December 2003. A case was defined as an individual from the study base who for the first time received a diagnosis of RA according to the American College of Rheumatology criteria of 1987. Controls were randomly selected from the study base with consideration taken for age, gender and residential area. Cases (n = 1,419) and controls (n = 1,674) answered an extensive questionnaire regarding lifestyle factors and occupational exposures, including different types of mineral oils. Sera from cases and controls were investigated for RF and anticitrulline antibodies. Among men, exposure to any mineral oil was associated with a 30% increased relative risk of developing RA (relative risk = 1.3, 95% confidence interval = 1.0-1.7). When cases were subdivided into RF-positive RA and RF-negative RA, an increased risk was only observed for RF-positive RA (relative risk = 1.4, 95% confidence interval 1.0-2.0). When RA cases were subdivided according to the presence of anticitrulline antibodies, an increased risk associated with exposure to any mineral oil was observed only for anticitrulline-positive RA (relative risk = 1.6, 95% confidence interval = 1.1-2.2). Analysis of the interaction between oil exposure and the presence of HLA-DR shared epitope genes regarding the incidence of RA indicated that the increased risk associated with exposure to mineral oil was not related to the presence of shared epitope genotypes. In conclusion, our study shows that exposure to mineral oil is associated with an increased risk to develop RF-positive RA and anticitrulline-positive RA, respectively. The findings are of particular interest since the same mineral oils can induce polyarthritis in rats.

Adolescent↗