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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A case of Feuerstein-Mims syndrome (naevus sebaceous, convulsions and mental retardation) is described in association with vitamin D resistant reckets.
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PMID:Feuerstein and Mims syndrome with resistant rickets. 18 80

Screening of three human hepatoma-derived cell lines revealed the presence of an immunologically similar plasma binding protein for vitamin D and its metabolites in media from Hep 3B cells. Approximately 3% of protein synthesized and secreted by these cells was immunoprecipitated by specific antiserum to the D-binding protein. Medium content of the protein increased over 11 days following cell seeding, and negligible amounts of 125I-labeled binding protein added to cultures were degraded over 48 h. The hepatoma-derived binding protein was indistinguishable from plasma binding protein or reference pure protein in gel filtration, sucrose gradient ultracentrifugation, and polyacrylamide gel electrophoresis systems. The Hep 3B cell product was found to bind mole/mol with monomeric actin, and bind vitamin D sterols with an affinity and specificity characteristic of the human plasma binding protein. The findings argue strongly for the identity of the Hep 3B cell product and the human plasma protein. The continuous availability of the Hep 3B cell line provides a reasonable model for investigations of biosynthesis and release of this important plasma protein.
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PMID:Characterization of the human plasma binding protein for vitamin D and its metabolites synthesized by the human hepatoma-derived cell line, Hep 3B. 630 61

The role of vitamin D in mineral uptake in the gastrointestinal tract (GIT) of mole-rats (Heterocephalus glaber and Cryptomys damarensis; family Bathyergidae), animals with a naturally impoverished vitamin D status, was investigated. We measured relative rates of passage of radioactive markers, mode of calcium (Ca) uptake, paracellular movement and the opening of voltage-sensitive Ca channels (VSCCs) along the GIT with and without oral vitamin D3 supplementation. The ratio of relative absorption of labelled 45Ca to [14C]polyethylene glycol ([14C]PEG) indicated that within 24 h more than 88% of the Ca in the diet had been absorbed. Most absorption occurred in the duodenum within 12 h. The contribution of the hindgut (caecum and proximal and distal colon) to total Ca absorption was small (approximately 11%). Only passive uptake occurred in the duodenum (serosal (S): mucosal (M) ratios approximately 1). Active uptake occurred in the hindgut (S:M > 2), although hindgut absorption appears to play a secondary role to passive uptake in the duodenum. Vitamin D3 supplementation had no effect on the mode of Ca uptake in either the small intestine or the hindgut. Although we found VSCCs in mole-rat intestinal epithelial cells, they occurred in very low concentrations. Calcium influx through VSCCs did not change following vitamin D stimulation. Furthermore, mole-rats pretreated with intraperitoneal (I.P.) 1,25(OH)2D3 showed no enhancement of VSCC Ca uptake, indicating that active uptake plays a minor role, if any, in GIT mineral absorption. Our data support the hypothesis that intestinal Ca transport in mole-rats is independent of both genomic and non-genomic vitamin D mediation.
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PMID:Intestinal calcium transport in mole-rats (Cryptomys damarensis and Heterocephalus glaber) is independent of both genomic and non-genomic vitamin D mediation. 757 99

Naked mole-rats have no access to obvious sources of vitamin D and therefore have an impoverished vitamin D status. In an investigation into the effects of vitamin D supplementation, inadvertently supraphysiological doses of 130,000 times the normal dose of vitamin D were administered. Within 5 days animals appeared lethargic, with reduced food intake. All but one of the seven animals were killed and blood was collected. Plasma vitamin D metabolites 25(OH)D and 1,25(OH)2D and calcium were determined. Both vitamin D metabolite concentrations exceeded the upper limits of sensitivity of the assays (> 100 ng/ml 25(OH)D and > 210 pg/ml 1,25(OH)2D). Active calcium uptake in the intestine was evident along with concomitant increases in calcium concentration in plasma, bone, and teeth. The remaining animal survived, but showed scab-like formations in the skin around the lower jaw and along the nipple line. X-ray analyses revealed calcium deposition in these cornified regions, although there was no evidence of metastatic calcification in other tissues. Deposition of excess calcium in skin that is regularly sloughed off and in teeth that are continuously worn down and replaced may reduce the vitamin D-induced hypercalcaemia and thus alleviate the effects of vitamin D intoxication.
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PMID:Vitamin D3 intoxication in naked mole-rats (Heterocephalus glaber) leads to hypercalcaemia and increased calcium deposition in teeth with evidence of abnormal skin calcification. 765 55

The Damara mole-rat, Cryptomys damarensis, has no access to obvious dietary or endogenous sources of vitamin D. We tested the hypotheses that mineral metabolism in these animals is independent of vitamin D status but rather is affected by dietary calcium (Ca) content. Furthermore, we questioned whether bone and teeth assist in plasma mineral homeostasis. Mole-rats increased Ca intake when dietary Ca content increased; however, mode of gastrointestinal uptake, vitamin D metabolite and plasma Ca concentrations were not altered. Similarly, oral vitamin D supplementation did not affect gastrointestinal Ca absorption or alter plasma Ca concentration, although significant increases in plasma concentrations of vitamin D were evident. Bone and teeth mineral (Ca and Pi) content were augmented with vitamin D supplementation. Mineral homeostasis was primarily maintained by manipulating mineral deposition in teeth, for mineral content in teeth increased significantly when dietary Ca content changed from 1.3 g/kg to 2.6 g/kg and higher. Mineral homeostasis in these subterranean rodents does not appear to be regulated at the level of the intestine, but rather by manipulating bone and teeth mineral reservoirs.
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PMID:The effect of dietary calcium content and oral vitamin D3 supplementation on mineral homeostasis in a subterranean mole-rat Cryptomys damarensis. 771 22

The vitamin D hormone 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is generated by a series of hydroxylation steps in the liver and kidneys. We investigated whether naturally vitamin D-deficient subterranean mammals (naked mole rats, Heterocephalus glaber) employ the same enzymatic pathways, and whether these are regulated in a similar manner to that established for other mammals. Vitamin D3-25-hydroxylase in the liver and both 25-hydroxyvitamin D3-1-hydroxylase and 25-hydroxyvitamin D3-24 hydroxylase (1-OHase and 24-OHase) in the kidney were detectable in mole rats. As expected for vitamin D-deficient mammals, the 1-OHase activity predominated over the 24-OHase. After mole rats received a supraphysiological supplement of vitamin D3, 1-OHase activity was suppressed and 24-OHase activity was enhanced. Irrespective of vitamin D status, forskolin (a protein kinase A activator) and dibutyryl cyclic AMP did not alter the activity of either 1-OHase or 24-OHase. These findings suggest that the response of renal hydroxylases to parathyroid hormone was blunted. Phorbol esters, 12-O-tetradecanoylphorbol 13-acetate (TPA) and 1-oleoyl-2-acetylglycerol (OAG) (protein kinase C activators), suppressed 1-OHase activity. 24-OHase activity was induced by TPA but not by OAG. These effects were similar to those illicited by vitamin D3 supplementation but were additive in that they increased the responses shown in vitamin D-replete mole rats. These data confirm that naturally vitamin D-deficient mole rats can convert vitamin D3 to the hormone, 1,25(OH)2D3.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vitamin D hydroxylases and their regulation in a naturally vitamin D-deficient subterranean mammal, the naked mole rat (Heterocephalus glaber). 785 93

Calcitriol [1,25(OH)2D3] actions on intestinal calcium transport involve genomic and nongenomic pathways. Whether nongenomic 1,25(OH)2D3-mediated actions are employed was investigated using isolated intestinal epithelial cells of naturally vitamin D-deficient underground-dwelling damara mole-rats (Cryptomys damarensis). 1,25(OH)2D3-mediated nongenomic pathways of intestinal calcium uptake, measured by opening of 1,25(OH)2D3-activated voltage-sensitive Ca2+ channels (VSCC), did not occur. Rapid (1 min) 45Ca2+ transmembrane influx in intestinal cells was not significantly increased by the addition of 1,25(OH)2D3 (at concentrations from 10(-12) to 10(-6) nM), when compared to opening of VSCC in the presence of a depolarizing (elevated K+) buffer. Furthermore, even after 30 min calcium uptake was not significantly enhanced by the hormone. These findings support earlier reports that duodenal calcium absorption is independent of vitamin D and is a highly adaptive feature of a subterranean existence.
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PMID:Absence of calcitriol-mediated nongenomic actions in isolated intestinal cells of the damara mole-rat (Cryptomys damarensis). 792 52

1,25-dihydroxyvitamin D3 (1,25(OH)2D3), the hormonally active metabolite of vitamin D3 interacts with its nuclear/cytosolic receptor to induce biological responses in target tissues. Naked mole rats appear to be naturally deficient in vitamin D. The questions arise whether these animals possess the 1,25(OH)2D3 receptor (VDR) and whether they are capable of responding to 1,25(OH)2D3 via receptor-mediated pathways. Various tissues (intestine, kidney, Harderian glands, and skin) were examined for the presence and biochemical characterization (as indicated by saturation, sucrose density gradient, DNA binding, and ligand-competitive analysis) of VDRs. In addition homologous upregulation of VDRs in these tissues and induction of 25-hydroxyvitamin D3-24-hydroxylase (24-OHase) in the kidney was studied as indicators of the VDR-mediated biological responses. Naked mole rats have VDRs in the intestine, kidney, and Harderian gland but not in skin. Biochemical characterization of VDRs and VDR-mediated biological responses in the intestine and kidney correspond to those found in similar target tissues of other mammals. Harderian gland VDR is at a lower concentration yet shows a markedly higher affinity and selectivity to 1,25(OH)2D3 than that of the intestine and kidney. Vitamin D3 supplementation resulted in VDR upregulation in the intestine and kidney and induced renal 24-OHase but had no effects on VDRs in Harderian glands. These data demonstrate that naked mole rats possess VDRs in intestine, kidney, and Harderian glands; these VDRs differ in their biochemical characteristics.
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PMID:Vitamin D receptors in a naturally vitamin D-deficient subterranean mammal, the naked mole rat (Heterocephalus glaber): biochemical characterization. 822 60

beta-Lactoglobulin was isolated directly from acidic whey by bioselective adsorption on N-retinyl-Celite, yielding preparations of > or = 96% purity. Interactions of these preparations with vitamin D2, vitamin D3, ergosterol, cholesterol, and 7-dehydrocholesterol were examined by following changes in the fluorescence spectra. Both the excitation and emission spectra indicated that energy was transferred between the tryptophanyl residues of the protein and the chromophore of the ligand. Analyses of the fluorescence changes that occurred upon titration of beta-LG with the various ligands allowed determination of the dissociation constant for the complex and the number of moles bound per mole of protein. The affinity for vitamin D2 (dissociation constant of 4.91 nM) was 10-fold higher than that of the other compounds, except for ergosterol, which was 5-fold larger than the others. Also, the affinity was 10-fold higher than that typically reported for the retinoids. Furthermore, the value obtained for the number of moles bound per mole of protein was 2 mol.mol-1 for each of the ligands examined in this study; it has been well established that all of the retinoids are bound with a stoichiometry of 1.0. These results suggest that beta-LG may be a better carrier of vitamin D than of vitamin A.
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PMID:Binding of vitamin D and cholesterol to beta-lactoglobulin. 920 74

Epidermal nevus syndrome is characterized by congenital anomalies affecting multiple body systems, especially the skin, skeleton and central nervous system. A form of rickets/osteomalacia that is markedly resistant to treatment with vitamin D has been reported in children with this syndrome. We report the clinical and laboratory observations in a child with epidermal nevi and severe hypophosphatemic rickets/osteomalacia.
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PMID:Hypophosphatemic vitamin-D resistant rickets associated with epidermal nevus syndrome. A case report. 922 23


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