Mineral losses

LT4 doses sufficient to suppress tumor growth may result in a suppressed TSH and mild hyperthyroidism. These patients must be monitored closely for complications of the mild hyperthyroid state, such as bone mineral loss and development of atrial fibrillation. 

Calcium Metabolism, Bone Mineral Loss, and Soft Tissue Calcification in Rodents... 

The problem of bone mineral loss, which accompanies aging of both men and women, has recently received much attention of the scientific community because the proportion of the elderly in the population is increasing especially in Western Europe and North America (J, 2). Among the various factors which affect the integrity of the skeleton are habitual intakes of mineral nutrients such as calcium, phosphorus and fluoride. Here we report the results of our investigations on the interactions between these minerals in relation to bone and soft tissues. 

Formation of incipient lesions. Specimens were exposed alternately to acid and collagenase (fig. 1). Erosive lesions were formed by demineralization in HAc (pH 5.0 and pH 5.5), subsurface lesions by demineralization in HLac-MHDP (pH 4.5 and pH 5.0). All specimens were incubated separately in 1.0 ml acidic solutions for six hours and 1.0 ml collagenase or buffer for 18 hours daily. Under these conditions, the amount of degradable organic matrix is proportional to mineral loss (Klont and Ten Cate, 1991). Between the incubations, the specimens were rinsed briefly with distilled water and dried with paper. Each acid/collagenase and acid/buffer group contained five specimens. The experimental period was ten days. All incubations were carried out at 37°C without stirring. 

High mineral content of cheese curd at draining promotes the development of elastic texture. Minimum mineral loss from the curd occurs after draining. Cheese varieties with eyes (Swiss, Gouda) require elastic curds to permit round eye formation. These cheeses are drained... 

Henderson NK, Sambrook PN, Kelly PJ, Macdonald P, Keogh AM, Spratt P, Eisman JA. Bone mineral loss and recovery after cardiac transplantation. Lancet 1995 346(8979) 905. 

Early dental caries (incipient lesions) are non-cavitated and limited to the outer enamel surface. Clinically, these lesions are identified as visible white spots when the tooth is air-dried (Fig. 11.1). The incipient lesion is known as a subsurface lesion since the surface appears intact. However, histological investigations have shown that below the surface, there are zones that vary in porosity (voids from mineral loss) as well as biochemical composition (e.g. fluoride, water and carbonate content) [29]. The enamel caries can vary from a depth of 100-250 J.m (for incipient caries) to entirely through the enamel ( 1.5mm deep), at which point the cavitated lesion has extended into the underlying dentin [35]. The diagnostic challenge remains early caries detection and the focus has been on caries lesions that form on the tooth crown affecting the enamel. The remainder of the discussion will therefore concentrate on enamel caries. 

Several investigators have diagnosed bone mineral loss, with features of osteopenia/osteoporosis on radiography, quantitative computed tomography, or absorptiometry, in patients receiving long-term G-CSF for severe congenital... 

In another child, who had osteoporotic vertebral collapse, extensive investigations showed reduced bone mineral content, reduced concentrations of osteocalcin, and features of osteoporosis on bone biopsy (SEDA-19, 344). The role of G-CSF was unclear, because bone mineral loss is a possible complication of the underlying disease. Indeed, improvement or stabilization during G-CSF treatment was noted in several patients (6). Furthermore, there was no apparent effect on height, head circumference, or weight in patients under 18 years of age (6). In another study, there was bone mineral loss with features of osteopenia/osteoporosis in 15 of 30 patients treated with G-CSF for a mean of 5.8 years for severe chronic neutropenia (65). However, six of nine patients investigated before G-CSF treatment had evidence of osteopenia/osteoporosis. 

Tebas P, Powderly WG, Claxton S, Marin D, Tantisiriwat W, Teitelbaum SL, Yarasheski KE. Accelerated bone mineral loss in HIV-infected patients receiving potent antiretroviral therapy. AIDS 2000 14(4) F63-7. 

Rosenfeld JA. Can the prophylactic use of raloxifene, a selective estrogen-receptor modulator, prevent bone mineral loss and fractures in women with diagnosed osteoporosis or vertebral fractures West J Med 2000 173(3) 186-8. 

Brommage, R., and DeLuca, H. F. (1985). Regulation of bone mineral loss during lactation. Am. J. Physiol. 248, E182-E187. 

Fig. 3. Mean mineral density profiles of two artificial caries lesions. Mineralisation, as a percentage of sound enamel, assumed to be 87% mineral by volume, is expressed as a function of depth into the lesion. The two mineral distributions are clearly different but the amount of mineral loss is almost identical in each case. In the text, the terms shallow and deep refer to lesion depth, whereas the terms small lesion and Targe lesion refer to amount of mineral loss, regardless of depth. The heavy line represents a lesion with a high R parameter and the lighter line, a lesion with a lower R parameter (see 4.6).

Fig. 4. Mineral loss data expressed as a percentage of AZbase and in absolute terms ( = percentage = absolute). 

Lesions created in both bovine and human enamel, in an acidified methyl cellulose gel system, displayed many of the same qualitative trends [Lynch, unpubl. data]. After an initial period of approximately 3 days when dissolution was negligible, mineral loss was typically found at a series of discrete locations, with no apparent mineral loss between these pockets of demineralisation. Surface zones were typically poorly defined or absent. After 5 or more days, the isolated pockets had coalesced and lesions were uniform in terms of both depth and mineral loss across the bulk of the lesion body, with well-defined surface zones. When observed under polarised light, these initial pockets of demineralisation were very often coincident with Hunter-Schreger banding. This was particularly noticeable in bovine enamel. Shellis [64] reported variations in solubility related to enamel microstructure and suggested that structure/solubility relationships are likely to influence lesion formation. 

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