scholarly journals Bone marrow and serum concentrations of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, and 1.ALPHA.,25-dihydroxyvitamin D in patients with leukemia and normal subjects.

1989 ◽  
Vol 35 (4) ◽  
pp. 211-223 ◽  
Author(s):  
Sonoko MASUDA ◽  
Toshio OKANO ◽  
Kyoko NOMA ◽  
Mika HAMASAKI ◽  
Tadashi KOBAYASHI ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Normal Subjects ◽  
Serum Concentrations ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

Determinants of the serum concentration of 1,25-dihydroxyvitamin D in primary hyperparathyroidism

1989 ◽  
Vol 76 (1) ◽  
pp. 81-86 ◽  
Author(s):  
B. C. Lalor ◽  
E. B. Mawer ◽  
M. Davies ◽  
G. A. Lumb ◽  
L. Hunt ◽  
...  
Keyword(s):  
Vitamin D ◽  
Serum Concentration ◽  
Primary Hyperparathyroidism ◽  
Serum Concentrations ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Relevant Variables ◽  
Biological Determinants ◽  
25 Hydroxyvitamin D

1. The serum concentrations of 25-hydroxyvitamin D and 1,25-dihydroxyvitamin D were measured in 44 patients with primary hyperparathyroidism. 2. In 14 patients the serum concentration of 1,25-dihydroxyvitamin D was greater than normal (142–337 pmol/l). One patient had a subnormal concentration of 1,25-dihydroxyvitamin D (36 pmol/l) but no other evidence of vitamin D deficiency. 3. The possible biological determinants of the serum concentration of 1,25-dihydroxyvitamin D were sought by multivariate analysis of relevant variables. The serum concentration of 1,25-dihydroxyvitamin D was found to be significantly and positively correlated with the serum concentrations of 25-hydroxyvitamin D (P < 0.001) and parathyroid hormone (P < 0.003), and with the glomerular filtration rate (P < 0.03), and negatively correlated with the serum concentrations of calcium (P < 0.02) and phosphate (P = 0.055) (multiple R = 0.638,P < 0.002). 4. In primary hyperparathyroidism the major determinant of serum 1,25-dihydroxyvitamin D is the availability of precursor 25-hydroxyvitamin D. 5. The finding that serum 1,25-dihydroxyvitamin D is commonly normal in patients with primary hyperparathyroidism despite an adequate state of vitamin D nutrition, can be explained in terms of the constraining influences of hypercalcaemia and variable degrees of renal dysfunction on the biosynthesis of 1,25-dihydroxyvitamin D.

scholarly journals Influence of physical mobility and season on 25-hydroxyvitamin D-parathyroid hormone interaction and bone remodelling in the elderly

2000 ◽  
pp. 673-679 ◽  
Author(s):  
R Theiler ◽  
HB Stahelin ◽  
M Kranzlin ◽  
G Somorjai ◽  
L Singer-Lindpaintner ◽  
...  
Keyword(s):  
Vitamin D ◽  
The Elderly ◽  
Serum Concentrations ◽  
Institutionalized Elderly ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
1,25 Dihydroxyvitamin D ◽  
Physical Mobility ◽  
25 Hydroxyvitamin D ◽  
Mobility Status

OBJECTIVE: To investigate influences of physical mobility and season on 25-hydroxyvitamin D-intact parathyroid hormone (iPTH) interaction in the elderly. DESIGN: We examined 188 frail institutionalized elderly at the expected nadir of their serum vitamin D concentrations (winter). This group was compared with 309 healthy ambulatory elderly at the expected time of maximum vitamin D repletion (summer), to accentuate the influences of season and physical activity. METHODS: Serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, iPTH and urinary deoxypyridinoline (DPD) were measured. RESULTS: Vitamin D metabolites were significantly lower in the institutionalized elderly (P<0.0001), with an 82.5% prevalence of vitamin D deficiency (25-hydroxyvitamin D <12ng/ml) in institutionalized elderly in wintertime and 15.5% in ambulatory elderly in summertime. Overall, median iPTH did not differ between groups. However, median iPTH secretion in the presence of low vitamin D serum concentrations (5-30ng/ml) was greater in ambulatory elderly. This could be explained by lower mobility status being correlated with greater serum calcium concentrations (r=0.24, P=0.02 in women; r=0.35, P=0. 001 in men) and greater urinary excretion of DPD (r=0.41, P=0.0001 in women; r=0.42, P=0.0002 in men), independent of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D and iPTH. CONCLUSIONS: These data support the hypothesis that immobility, even in the presence of vitamin D deficiency, acts as an overriding influence on bone metabolism by promoting bone resorption (measured as urinary DPD) and increasing serum calcium independent of iPTH. Therefore mobility status may substantially affect 25-hydroxyvitamin D threshold values and the degree to which patients benefit from vitamin supplementation.

Serum Calcium and Vitamin D Status of Patients with Sickle Cell Disease in Curaçao

1997 ◽  
Vol 34 (2) ◽  
pp. 170-172 ◽  
Author(s):  
Fey P L van der Dijs ◽  
Fiona R M van der Klis ◽  
Fred D Muskiet ◽  
Frits A J Muskiet
Keyword(s):  
Vitamin D ◽  
Serum Calcium ◽  
Calcium Concentration ◽  
Vitamin D Status ◽  
Serum Concentrations ◽  
Cell Disease ◽  
Serum Calcium Concentration ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
25 Hydroxyvitamin D

We measured parameters of calcium homeostasis and vitamin D status in HbSS patients (median age 8 years, range 3–19; 8 females, 10 males) and matched HbAA controls living in the tropical island of Curaçao. Serum calcium concentration in HbSS patients [2·32(0·07) mmol/L] was lower (ANCOVA, P = 0·002) than that of HbAA controls [2·44(0·14)]. None of the subjects had hypocalcaemia. There were no differences in serum concentrations of phosphate, total protein, albumin, intact parathyroid hormone (PTH), 25-hydroxyvitamin D [87(27) nmol/L in patients, 86(15) nmol/L in controls) and 1,25-dihydroxyvitamin D. There were no significant relations between PTH and 25(OH)D. We conclude that vitamin D status of HbSS patients in Curaçao is adequate.

scholarly journals Vitamin D upregulates the macrophage complement receptor immunoglobulin in innate immunity to microbial pathogens

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Annabelle G. Small ◽  
Sarah Harvey ◽  
Jaspreet Kaur ◽  
Trishni Putty ◽  
Alex Quach ◽  
...  
Keyword(s):  
Vitamin D ◽  
Innate Immunity ◽  
Surface Expression ◽  
Microbial Pathogens ◽  
Cell Surface Expression ◽  
Complement Receptor ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Multistep Process ◽  
25 Hydroxyvitamin D

AbstractVitamin D deficiency remains a global concern. This ‘sunshine’ vitamin is converted through a multistep process to active 1,25-dihydroxyvitamin D3 (1,25D), the final step of which can occur in macrophages. Here we demonstrate a role for vitamin D in innate immunity. The expression of the complement receptor immunoglobulin (CRIg), which plays an important role in innate immunity, is upregulated by 1,25D in human macrophages. Monocytes cultured in 1,25D differentiated into macrophages displaying increased CRIg mRNA, protein and cell surface expression but not in classical complement receptors, CR3 and CR4. This was associated with increases in phagocytosis of complement opsonised Staphylococcus aureus and Candida albicans. Treating macrophages with 1,25D for 24 h also increases CRIg expression. While treating macrophages with 25-hydroxyvitamin D3 does not increase CRIg expression, added together with the toll like receptor 2 agonist, triacylated lipopeptide, Pam3CSK4, which promotes the conversion of 25-hydroxyvitamin D3 to 1,25D, leads to an increase in CRIg expression and increases in CYP27B1 mRNA. These findings suggest that macrophages harbour a vitamin D-primed innate defence mechanism, involving CRIg.

scholarly journals Vitamin D-Mediated Hypercalcemia: Mechanisms, Diagnosis, and Treatment

2016 ◽  
Vol 37 (5) ◽  
pp. 521-547 ◽  
Author(s):  
Peter J. Tebben ◽  
Ravinder J. Singh ◽  
Rajiv Kumar
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Active Form ◽  
Elevated Serum ◽  
Diagnosis And Treatment ◽  
Vitamin D Metabolites ◽  
Hydroxyvitamin D ◽  
Dihydroxyvitamin D ◽  
Stone Formers ◽  
25 Hydroxyvitamin D

AbstractHypercalcemia occurs in up to 4% of the population in association with malignancy, primary hyperparathyroidism, ingestion of excessive calcium and/or vitamin D, ectopic production of 1,25-dihydroxyvitamin D [1,25(OH)2D], and impaired degradation of 1,25(OH)2D. The ingestion of excessive amounts of vitamin D3 (or vitamin D2) results in hypercalcemia and hypercalciuria due to the formation of supraphysiological amounts of 25-hydroxyvitamin D [25(OH)D] that bind to the vitamin D receptor, albeit with lower affinity than the active form of the vitamin, 1,25(OH)2D, and the formation of 5,6-trans 25(OH)D, which binds to the vitamin D receptor more tightly than 25(OH)D. In patients with granulomatous disease such as sarcoidosis or tuberculosis and tumors such as lymphomas, hypercalcemia occurs as a result of the activity of ectopic 25(OH)D-1-hydroxylase (CYP27B1) expressed in macrophages or tumor cells and the formation of excessive amounts of 1,25(OH)2D. Recent work has identified a novel cause of non-PTH-mediated hypercalcemia that occurs when the degradation of 1,25(OH)2D is impaired as a result of mutations of the 1,25(OH)2D-24-hydroxylase cytochrome P450 (CYP24A1). Patients with biallelic and, in some instances, monoallelic mutations of the CYP24A1 gene have elevated serum calcium concentrations associated with elevated serum 1,25(OH)2D, suppressed PTH concentrations, hypercalciuria, nephrocalcinosis, nephrolithiasis, and on occasion, reduced bone density. Of interest, first-time calcium renal stone formers have elevated 1,25(OH)2D and evidence of impaired 24-hydroxylase-mediated 1,25(OH)2D degradation. We will describe the biochemical processes associated with the synthesis and degradation of various vitamin D metabolites, the clinical features of the vitamin D-mediated hypercalcemia, their biochemical diagnosis, and treatment.

scholarly journals Hormonal Contraceptive Use Is Associated With Higher Total but Unaltered Free 25-Hydroxyvitamin D Serum Concentrations

2018 ◽  
Vol 103 (6) ◽  
pp. 2385-2391 ◽  
Author(s):  
Stefan Pilz ◽  
Rima Obeid ◽  
Verena Schwetz ◽  
Christian Trummer ◽  
Marlene Pandis ◽  
...  
Keyword(s):  
Contraceptive Use ◽  
Hormonal Contraceptive ◽  
Serum Concentrations ◽  
Hydroxyvitamin D ◽  
25 Hydroxyvitamin D
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