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Objective To study the reproductive history of patients with hereditary 1,25-dihydroxyvitamin D–resistant rickets (HVDRR) who have a nonfunctioning vitamin D receptor (VDR). Design Retrospective cohort study. Setting Tertiary university-affiliated medical center. Patient(s) Sixteen HVDRR patients and six spouses, four female and two male. Intervention(s) None. Main Outcome Measure(s) The data on age at menarche, time of conception, and number of pregnancies, abortions, and healthy newborns as reported by HVDRR women and partners of HVDRR men were analyzed, as were the results of semen sample analyses from HVDRR men. Result(s) All 16 patients had normal puberty. The mean age at menarche was 13.8 ± 0.8 years. Two married HVDRR women reported four normal pregnancies and four healthy newborns. Four married HVDRR men reported 15 pregnancies and nine healthy newborns. The wives of two of these men, who are brothers, gave birth to three healthy newborns and had six natural miscarriages during the second trimester of pregnancy. Time to conceive for all the female study patients was Conclusion(s) The VDR is expressed throughout the organs of reproduction, suggesting a role for vitamin D in reproduction. However, the reproductive potential of HVDRR patients with a mutant VDR gene with a nonfunctioning VDR appears to be normal.

Background and AimsThe role of hepcidin in inflammatory bowel disease [IBD] in children with anaemia is poorly understood. However, it has been shown that vitamin D suppresses hepcidin expression. We aimed to assess serum hepcidin levels and the effect of vitamin D treatment on those levels in newly diagnosed IBD paediatric patients.MethodsEighty-five children were prospectively recruited in the Dana-Dwek Children’s Hospital [40 newly diagnosed IBD, 45 healthy controls, 47% female, mean age 13.5 ± 3.4 years]. Blood samples for measurement of interleukin 6 [IL-6], C-reactive protein [CRP], hepcidin, iron parameters and 25-hydroxyvitamin D [25-(OH)-D] levels were obtained at baseline. Patients with mild-to-moderate signs and symptoms of IBD were treated with 4000 units of vitamin D daily for 2 weeks, after which the blood tests were repeated.ResultsBasal hepcidin, IL-6, CRP and platelet counts were significantly higher, and haemoglobin, serum iron and transferrin levels were significantly lower in the IBD children compared to controls [p < 0.001]. Eighteen patients completed 2 weeks of treatment with vitamin D. Following treatment, serum 25-(OH)-D concentrations increased by 40% [from 22.5 to 32.5 ng/mL], and serum hepcidin, CRP and ferritin levels decreased by 81%, 81% and 40% [from 33.9 to 6.7 ng/mL, from 23.9 to 4.7 mg/L, and from 27 to 16 ng/mL, respectively] [p ≤ 0.001].ConclusionSerum hepcidin levels were significantly higher in IBD paediatric patients compared to controls. Following vitamin D treatment, serum hepcidin concentration decreased significantly. These findings suggest a potential role for vitamin D in treating anaemia in IBD children.ClinicalTrials.gov numberNCT03145896

Hepcidin is a master regulator of iron metabolism. Recently, it has been shown that vitamin D suppresses hepcidin expression. Our hypothesis was that hepcidin levels inversely correlate with vitamin D levels in anemic children during acute infection. A prospective study was performed on 90 patients (45 females, 45 males, mean age 7.3 ± 5 years) who were admitted to the pediatric ward. Sixty-two patients had infectious disease (32 with coexisting anemia, 30 without anemia), and 28 patients were hospitalized for noninfectious causes. Blood samples for IL-6, hepcidin, iron status parameters, and 25-hydroxyvitamin D (25-OHD) were obtained within 72 h after admission. Serum concentrations of IL-6 and hepcidin were significantly higher and 25-OHD, iron, and transferrin were significantly lower in anemic children with infectious disease compared with controls. Children with a serum 25-OHD level 20 ng/ml (OR: 6.1, CI: 1.15–32.76). Correlation analyses found positive associations between hepcidin levels and ferritin (R2 = 0.47, P

Two siblings (a 15-year-old boy and an 11-year-old girl) who presented with hypocalcemic seizure at the age of 2 years and 2 months (boy) and 2 years and 4 months (girl) were diagnosed with hypoparathyroidism. At the age of 3 years, the girl developed central diabetes insipidus with good response to desmopressin acetate treatment. The family history was unremarkable, and there was no consanguinity between the parents. The father is of Iraqi/Egyptian Jewish origin and the mother is of Iranian/Romanian Jewish origin. Sequence analysis of the candidate genes for isolated hypoparathyroidism encoding calcium-sensing receptor, parathyroid hormone, and glial cells missing homolog B did not reveal any mutations. Whole-exome sequencing identified a homozygous mutation in the autoimmune regulatory gene (AIRE), c.374A>G;p.Y85C, characteristic for Jewish Iranians with autoimmune polyendocrine syndrome type 1 (APS1), which was confirmed by the Sanger sequencing. Antibodies against the adrenal, pancreatic islet cell, ovary, thyroid, pituitary, celiac, and parietal cell were negative in both siblings, while anti-diuretic hormone antibodies were positive only in the girl. No other symptoms or signs of APS1 developed during all the years of follow-up. Conclusion: APS1 should be part of the differential diagnosis in children presenting with isolated hypoparathyroidism or hypoparathyroidism with central diabetes insipidus (CDI). These cases show that the AIRE mutation characteristic of Iranian Jews can also be found in non-Iranian Jews.

Israel is a country with a sunny climate; however, vitamin D deficiency and insufficiency are common findings in certain populations whose exposure to sunlight is limited. Medical residency is known for long indoor working hours, thus theoretically limiting the opportunities for sun exposure.To evaluate whether the vitamin D status among residents in a single medical center in Tel Aviv is below the normal range.Forty-six residents (28 females, 18 males, average age 33.9 ± 2.8 years) in three residency programs (internal medicine, general surgery/obstetrics and gynecology, pediatrics) were recruited. Demographic data, personal lifestyle, physical activity details and sun exposure duration were obtained by a questionnaire. Serum levels for 25(OH)D were analyzed by a radioimmunoassay.The mean serum 25(OH)D concentration was 29.8 ± 5.8 ng/ml. According to Institute of Medicine definitions, none of the residents were vitamin D deficient and only two residents (4%) were vitamin D insufficient (15 ng/ml each). The level of 25(OH)D was similar among the various medical specialties. The 25(OH)D levels correlated with the duration of sun exposure and the number of offspring (regression analysis: R2 = 9.2%, P0.04 and R2 = 8.9%, P0.04, respectively), but not with nutritional data, blood chemistry, or extent of physical activity.Most of the residents maintained normal or near normal 25(OH)D levels, indicating that the residency program itself did not pose a significant risk for vitamin D deficiency.

Previous studies have reported an association between vitamin D deficiency and asthma. Hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR) patients provide a natural model to assess the role of the vitamin D receptor (VDR) in regulating human lung immune responses and airway hyperreactivity.The aim of the study was to determine the role of the VDR on lung functions, airways, and systemic markers of inflammation and allergy in HVDRR patients.Thirteen HVDRR patients (aged 6-37 y) and 17 normal controls (aged 6-38 y) underwent spirometry, a methacholine challenge test (MCT), blood tests, allergy skin tests, determination of fractional exhaled nitric oxide, and measurement of serum and exhaled breath condensate cytokines, including IL-4, IL-5, IL-10, IL-17, and interferon-γ levels.All HVDRR patients had negative MCT results, whereas six controls (35.3%) had positive MCT results (P.014). Serum IgE levels, eosinophil counts, and fractional exhaled nitric oxide and allergy skin test results were similar for the HVDRR patients and controls, as were the serum cytokine concentrations. The HVDRR patients had different cytokine levels in their exhaled breath condensate (increased IL-4 and IL-17 and decreased IL-5, IL-10, and interferon-γ levels) compared to the controls (P.005).HVDRR patients show diverse exhaled cytokine profiles but seem to be protected against provoked bronchial hyperreactivity and clinical asthma. These findings suggest that an intact VDR has an important role in asthma pathophysiology.

Vitamin D has regulatory effects on innate and adaptive immunity. Curiously, hereditary vitamin D-resistant rickets (HVDRR) patients show no increased incidence of infectious or autoimmune diseases.The aim of the study was to investigate the role of vitamin D and the vitamin D receptor (VDR) in innate and adaptive immune responses in monocytes and lymphocytes from HVDRR patients.Fifteen HVDRR patients and 17 controls participated in the investigation. Activated monocytes (lipopolysaccharides) and lymphocytes (anti-CD3, CD28, and α-GalCer) were incubated with and without 25(OH)D3 (100 nM). The mRNA expressions of CYP27B1 and VDR; vitamin D response (TLR2); vitamin D response elements binding protein (hnRNP); antimicrobial peptides cathelicidin and β-defensin; the transcription factor enhancer binding proteins C/EBPα, C/EBPβ, and C/EBPε and enzymes involved in NO generation, Nos2, and Arginase1 were analyzed by RT-PCR. TNF-α, interferon-γ, IL-4, IL-10, and IL-17 concentrations in lymphocyte cultures media were measured by ELISA.Cathelicidin expression was lower in HVDRR monocytes than in control monocytes. 25(OH)D3 increased significantly the expression of cathelicidin in control monocytes (2.3-fold) but only slightly in HVDRR monocytes. 25(OH)D3 increased the expression of VDR (2-fold), C/EBPε (2-fold), C/EBPβ (1.7-fold), and hnRNP and suppressed TLR2 only in control monocytes. Unexpectedly, 25(OH)D3 increased the expression of CYP27b1, C/EBPα, Nos2, and Arginase1 in HVDRR monocytes. TNFα and IL-17 concentrations were significantly higher in HVDRR lymphocyte cultures than in controls. 25(OH)D3 suppressed IL-17 only in control lymphocyte. 25(OH)D3 increased IL-4, IL-10, and interferon-γ concentrations in control lymphocyte media but not in HVDRR.Our results demonstrate impairments in various components of innate immunity in HVDTRR patients' monocytes and a proinflammatory cytokine profile in their lymphocytes. The underlying VDR-independent compensatory mechanisms that protect HVDRR patients from infections and autoimmune diseases remain undetermined.

Hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR) is caused by mutations in the vitamin D receptor gene. Children with HVDRR suffer from severe hypocalcemia and rickets that are treatable with extremely high-dose calcium supplements. Surprisingly, spontaneous recovery of calcium metabolism occurs after the end of puberty without the need for further calcium supplementation.To evaluate the role of vitamin D receptor in intestinal calcium absorption and bone, we investigated intestinal fractional calcium absorption (FCA), bone calcium accretion (Vo+), bone mineral density (BMD), and bone structure parameters in HVDRR patients from infancy into adulthood.Seventeen HVDRR patients aged 1.5-37 yr were investigated. FCA and Vo+ were determined by stable-calcium isotopes. BMD was determined by dual-energy x-ray absorptiometry and bone structure by high-resolution magnetic resonance imaging.FCA in patients aged 1.5-17 yr was 34.9 ± 11.2% compared with 57.3 ± 2.0% in age-matched controls (P0.00004), whereas in patients aged 18-26 yr, it was 82.0 ± 7.8 and 53.6 ± 1.2% in controls (P0.001). FCA of patients older than 29 yr was comparable to controls. Patients aged 18-26 yr had higher Vo+ than controls (P0.02). Patients under 18 and over 29 yr of age had Vo+ comparable to controls. Femoral-neck BMD Z-score was -2.38 ± 0.3 in patients under 18 yr and 0.28 ± 0.87 in postpubertal patients (P0.0001). Bone structure by high-resolution magnetic resonance imaging and bone parameters of HVDRR patients and controls were similar.Evidence from HVDRR patients reveals that calcium absorption is highly vitamin D dependent during infancy until the end of puberty, after which there is a period of about 10 yr in which mechanisms other than vitamin D-dependent ones are substantially involved in calcium absorption.

Vitamin D deficiency has been linked to hypertension and an increased prevalence of cardiovascular risk factors and disease. Studies in vitamin D receptor knockout (VDR KO) mice revealed an overstimulated renin-angiotensin system (RAS) and consequent high blood pressure and cardiac hypertrophy. VDR KO mice correspond phenotypically and metabolically to humans with hereditary 1,25-dihydroxyvitamin D-resistant rickets (HVDRR). There are no data on the cardiovascular system in human HVDRR. To better understand the effects of vitamin D on the human cardiovascular system, the RAS, blood pressure levels, and cardiac structures were examined in HVDRR patients. Seventeen patients (9 males, 8 females, aged 6 to 36 years) with hereditary HVDRR were enrolled. The control group included age- and gender-matched healthy subjects. Serum calcium, phosphorous, creatinine, 25-hydroxyvitamin D [25(OH)D],1,25-dihydroxyvitamin D(3) [1,25(OH)(2) D(3) ], parathyroid hormone (PTH), plasma rennin activity (PRA), aldosterone, angiotensin II (AT-II), and angiotensin-converting enzyme (ACE) levels were determined. Ambulatory 24-hour blood pressure measurements and echocardiographic examinations were performed. Serum calcium, phosphorus, and alkaline phosphatase values were normal. Serum 1,25(OH)(2) D(3) and PTH but not PRA and ACE levels were elevated in the HVDRR patients. AT-II levels were higher than normal in the HVDRR patients but not significantly different from those of the controls. Aldosterone levels were normal in all HVDRR patients. No HVDRR patient had hypertension or echocardiographic pathology. These findings reveal that 6- to 36-year-old humans with HVDRR have normal renin and ACE activity, mild but nonsignificant elevation of AT-II, normal aldosterone levels, and no hypertension or gross heart abnormalities.

Background : The infl ammatory marker, high-sensitivity C-reactive protein (HsCRP), is known to be related to non- allergic asthma, obesity, cardiovascular disease and smoking in adults. The aim of the present study was to determine whether HsCRP is related to respiratory symptoms and pulmonary function test fi ndings in asthmatic children. Methods : HsCRP was measured in 63 asthmatic children aged 2 - 12 years. The measurements were performed in 37 children during an episode of acute exacerbation and in 42 children during remission. Results : HsCRP level (14.28 ± 8.45 mg/L) during exacerbation was signifi cantly higher than the mean level (1.92 ± 3.16 mg/L) during remission ( P < 0.0001), with the decrease being more prominent in children with a low body mass index percentile ( P < 0.05). A reciprocal relationship was found between forced expiratory volume in 1 s and high-sensitivity C-reactive protein values ( P 0.049). Conclusion : Elevated HsCRP levels were signifi cantly associated with respiratory impairment in children.

Human osteoblasts (hOB) produce and respond to 1,25(OH)(2)D(3) (1,25D), suggesting an autocrine/paracrine system. We therefore examined hormonal modulation of the expression and activity of 25 hydroxy-vitamin D(3)-1alpha hydroxylase (1-Ohase) in hOB. Cells from pre- and post-menopausal women or men, were treated with estrogenic compounds and 1-OHase expression and activity were measured. 1-OHase mRNA expression was highest in pre-menopausal women hOB and was increased by all hormones tested. In post-menopausal hOB all hormones except biochainin A (BA) and genistein (G) increased 1-OHase mRNA expressions to less extent. In male-derived hOB only dihydrotestosterone (DHT) and carboxy BA (cBA) increased 1-OHase mRNA expression. 1,25D production from 25(OH)D(3) had a K(m) of approximately 769-400 ng/ml (1.92-1.07 microM) and V(max) of 31.3-17.4 ng/ml (0.078-0.044 microM/60 min/5 x 10(6)cells) respectively, and was increased by all hormones except raloxifene (Ral) with higher stimulation in pre- than in post-menopausal cells. Only BA was almost five times more potent in pre- rather than post-menopausal hOBs. In male hOB only DHT and cBA increased 1,25D production whereas estradiol-17beta (E(2)) had no effect and BA decreased it. These results provide evidence for the expression of 1-OHase mRNA and production of 1,25D in hOBs, which are age and sex dependent and are hormonally modulated. The role of this local autocrine/paracrine 1,25D system in bone physiology deserves further investigation.

Vitamin D metabolites and analogs exert a variety of biological activities, such as regulation of cellular proliferation, differentiation and energy metabolism, exerted through the brain type isozyme of creatine kinase (CK) specific activity, serving to provide ATP generation. In the present study we assess the role of vitamin D in induction of CK in rat epiphyseal cartilage (Ep) and diaphyseal bone (Di). Skeletal tissues from female or male vitamin D-depleted rats showed lower CK than in vitamin D-replete rats in both Ep and Di. Moreover, estradiol-17beta (E2) or dihydrotestosterone (DHT), which increased CK in Ep and Di of intact female or male rats, respectively, stimulated CK in vitamin D-depleted rats to a much lower extent. Treatment of intact female rats for 1, 2 or 8 weeks with the less-calcemic vitamin D analogs JKF 1624F2-2 (JKF) or QW 1624F2-2 (QW) and the non-calcemic analog CB 1093 (CB), slightly affected CK, although there was an up-regulation of the E2- and DHT-induced CK response in Ep and Di from these rats. In intact female rats, all vitamin D analogs potentiated CK response to the SERM raloxifene (Ral) and tamoxifen (TAM) in these organs but the inhibitory effect of Ral or TAM on E2-induced CK was lost after this pre-treatment. CB induced a significant increase in estradiol receptor alpha (ERalpha) protein in both Ep and Di from intact female rats. Collectively, these results indicate that vitamin D analogs modulate CK in skeletal tissues and up-regulate its response and sensitivity to E2 and to SERM in these tissues, possibly via an increase in ERalpha protein. These results corroborate our previous studies in human bone cells, and further suggest that the vitamin D system plays an important physiological role in maintaining normal cell energy reservoir in the skeleton.

Context: Puberty is associated with increased dietary calcium absorption. However, little is known about the metabolic adaptations that enhance calcium absorption during puberty. Objectives: To investigate duodenal 25-hydroxy vitamin D-1α-hydroxylase (CYP 27B1) mRNA expression and duodenal 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) production in children, adolescents, and adults. Design and Methods: CYP27B1and IGF1 mRNA expression and 1,25(OH)2D3 production were determined in duodenal biopsies. CYP27B1 expression was also determined after IGF1R inhibitor treatment of human and mice duodenal explants. mRNA expression was determined by RT-PCR, and CYP27B1 activity was determined by incubating duodenal explants with 25(OH)D3 and measuring 1,25(OH)2D3 production by radioimmunoassay. Results: CYP27B1 mRNA expression was 13.7 and 10.4 times higher in biopsies from adolescents compared to adults and children, respectively. IGF1 mRNA expression was 30% and 45% higher in explants from adolescents and children, respectively, compared to adults. Inhibition of IGF1 receptor activity decreased CYP27B1expression in explants from both mice (85%) and humans (24%). 1,25(OH)2D3 production reached a maximum velocity of 768 ± 268 pmol/l/mg protein at 748.8 nmol/l of 25(OH)D3 in children and adolescents, whereas the maximum velocity was 86.4 ± 43.2 pmol/l/mg protein in adults. The substrate concentration at which the enzyme shows half of its maximum activity was similar in all groups, ranging between 624 and 837 nmol/L of 25(OH)D3. Conclusions: Increased CYP27B1 expression and local duodenal 1,25(OH)2D3 production during puberty may be a metabolic adaptation that promotes dietary calcium absorption. IGF1, a major factor in skeletal growth, is also involved in the modulation of CYP27B1 expression in the gut and may increase calcium supply for the growing bone.

1,25(OH)2D3, the active form of vitamin D, has an antiproliferative and antifibrotic effect on hepatic stellate cells. Our aim was to investigate the potential of 1,25(OH)2D3 to inhibit the development of liver fibrosis and to ameliorate established fibrosis in vivo. The antifibrotic effect of 1,25(OH)2D3 was investigated in a thioacetamide (TAA) model (as a preventive treatment and as a remedial treatment) and in a bile duct ligation model. In the preventive model, rats received simultaneously intraperitoneum injection of TAA and/or 1,25(OH)2D3 for 10 wk. In the remedial model, rats were treated with TAA for 10 wk and then received 1,25(OH)2D3 or saline for 8 wk. Fibrotic score was determined by Masson staining. Collagen I, α-smooth muscle actin (α-SMA), tissue inhibitor of metalloproteinase-1 (TIMP1), platelet-derived growth factor (PDGF), and transforming growth factor-β (TGF-β) expression were measured by Western blot analysis and real-time PCR. Hypercalemia was detected by chemistry measurements. Preventive treatment of 1,25(OH)2D3 significantly suppressed liver fibrosis both macroscopically and microscopically and significantly lowered the fibrotic score of the TAA + 1,25(OH)2D3 group compared with the TAA group. 1,25(OH)2D3 significantly inhibited expression of PDGF and TGF-β by ∼50% and suppressed the expression of collagen Iα1, TIMP1, and α-SMA by approximately three-, two-, and threefold, respectively. In contrast, 1,25(OH)2D3 was inefficient in amelioration of established liver fibrosis. Administration of 1,25(OH)2D3 to bile duct ligation rats led to a high mortality rate probably caused by hypercalcemia. We conclude that 1,25(OH)2D3 may be considered as a potential preventive treatment in an in vivo model but failed to ameliorate established cirrhosis.

We demonstrated previously that vitamin D metabolites modulate the response of bone and cartilage cells to 17β-estradiol (E2) and dihydrotestosterone (DHT) both in cell cultures and in vivo. In the present study, we investigated to what extent pretreatment with 1,25(OH)2D3 or 24,25(OH)2D3 would reduce the minimal effective dose of E2, DHT or progesterone (P) required for stimulation of DNA synthesis and creatine kinase specific activity in cultured osteoblast-like ROS 17 2.8 cells and in rat embryo epiphyseal cartilage cells, and to what extent such pretreatment would increase the maximal response. We measured responses to sex steroids after pretreatment of the cells for 5 days with 0.02% ethanol vehicle or with the vitamin D metabolites 1,25(OH)2D3 (0.12 nM), or 24,25(OH)2D3 (1.2 nM) singly or in combination. Pretreatment of ROS 17 2.8 cells with 1,25(OH)2D3, but not 24,25(OH)2D3, increased synergistically their response to E2 but not to P, and did not affect their lack of response to DHT. Pretreatment of epiphyseal cartilage cells with either 1,25(OH)2D3 or 24,25(OH)2D3 increased synergistically their DNA synthetic response to all three steroids, but their CK response only to E2 or DHT. The minimal dose for causing a significant response to E2 in ROS 17 2.8 cells or to either E2 or DHT in epiphyseal cartilage cells was reduced 10-fold after pretreatment with vitamin D metabolites. After pretreatment, the maximal response was more than doubled in ROS 17 2.8 cells; epiphyseal cartilage cells showed a similar 10-fold decrease in the dose required for maximal response to E2 or DHT; the improvement in the response to P was significant only for DNA synthesis. We conclude that pretreatment with the appropriate vitamin D metabolite(s) both reduces by an order of magnitude, or more, the amount of sex steroids needed to stimulate skeletal derived cells and increases synergistically the maximal response of the cells.

In the past three decades, our understanding of the physiologic functions of vitamin D1 has extended and includes many unexpected non-classic biological actions. Vitamin D receptors (VDR) and 25-hydroxyvitamin D-1αhydroxylase, the enzyme responsible for the production of 1,25(OH)2D3, the active form of vitamin D, are present in many tissues which are not associated with calcium or bone metabolism. Indeed, 1,25(OH)2D regulates cell proliferation, differentiation and apoptosis in many normal and cancer cells. Epidemiologic studies have shown that vitamin D deficiency increases the risk of cancer, cardiovascular disease and autoimmune disease. However, large scale randomized controlled intervention trials are needed to prove the effects of vitamin D on the prevention and treatment of these diseases. Expression of vitamin D or its metabolites without a subscript refer to both vitamin D2 and vitamin D3 or their metabolites.

Parathyroid hormone-related protein (PTHrP) expressed by human cancer cells enhances tumor cell growth and metastasis in vivo and it is considered as the major factor responsible for humoral hypercalcemia of malignancy. Hypoxia is a widespread feature of most solid tumors. Here, we studied the effects of hypoxia on PTHrP expression. We found that PTHrP is transcriptionally induced by prolonged (48 h) hypoxia in multiple human cancer and endothelial cell lines. Pharmacological up or downregulation of hypoxia-inducible factor (HIF) resulted in induction or reduction of PTHrP levels, respectively, implying that PTHrP hypoxic induction is mediated by HIF pathway. Analysis of PTHrP promoter revealed that both HIF-1α and HIF-2α subunits bind to specific hypoxia-responsive elements (HRE) within the P2 promoter of PTHrP. However, only HIF-2α can drive direct transcriptional activation, which can be abolished by mutation in the specific HRE. To the best of our knowledge, these results provide for the first time evidence that PTHrP is regulated by hypoxia in cancer and endothelial cells through the HIF-2 pathway. We suggest that HIF-2 induced by intratumoral hypoxia or by other genetic alterations may contribute to the pathogenesis of hypercalcemia of malignancy and cancer aggressiveness by stimulation of PTHrP expression.

Parathyroid hormone-related protein (PTHrP) has the ability to activate parathyroid hormone receptors and cause hypercalcemia. High concentrations of PTHrP are found in human breastmilk of mothers of term-infants. It is not known whether PTHrP is excreted in preterm human milk. This study tested the hypothesis that PTHrP concentrations in milk obtained from mothers of preterm infants are similar to those found in milk from mothers of term infants.We collected samples of expressed human milk obtained from 27 mothers of preterm infants (27-34 weeks' gestation) and from 16 mothers of full-term infants. Samples were collected within the first 72 hours postpartum (colostrum) and again at 1 and 2 weeks postpartum. PTHrP concentrations in these samples were measured by two-site immunoradiometric assay.PTHrP concentrations were significantly higher in samples obtained after 1 week postpartum than in samples obtained during the first 72 hours of life in breastmilk obtained from mothers of both term and preterm infants (P0.0001). PTHrP concentrations were similar in colostrum and after 1 week in term and preterm milk. PTHrP concentrations after 2 weeks of lactation were significantly higher in samples obtained from mothers of term infants (P0.006).Human milk expressed by mothers of preterm infants contains amounts of PTHrP similar to those measured in milk expressed by mothers of term infants.

We have demonstrated previously that 17 beta-estradiol (E2) stimulates proliferation of skeletal tissues, both in vivo and in vitro, as measured by increased DNA synthesis and creatine kinase (CK) specific activity. The effect of E2 on bone is sex specific. E2 is active only in females and androgens only in males. By contrast, in cartilage of both sexes, dihydrotestosterone (DHT) as well as E2 stimulates CK specific activity and DNA synthesis. In bone, we find that sex steroids stimulate skeletal cell proliferation in gonadectomized as well as in immature rats. Ovariectomized (OVX) rats, between 1 and 4 weeks after surgery, show stimulation of CK by E2. The basal activity and response of CK changes with the varying endogenous levels of E2 in cycling rats, in which the highest basal activity is at proestrus and estrus and the highest response is in diestrus. In rats of all ages tested, both the basal and stimulated specific activity of CK is higher in diaphysis and epiphysis than in the uterus, or in the adipose tissue adjacent to the uterus, which has a response similar to that of the uterus itself. The effect of E2 in vivo, and in chrondroblasts and osteoblasts in vitro, is inhibited by high levels of the antiestrogen tamoxifen which, by itself, in similar high concentrations, shows stimulatory effects. In addition to the sex steroids, skeletal cells are also stimulated by secosteroid and peptide calciotrophic hormones. The interactions of the sex steroids with these hormones modulate the response of cartilage and bone cells to both sex steroids and the other calciotrophic hormones. These results provide the first steps towards understanding the regulation of bone cell proliferation and growth by the concerted action of a variety of hormones and growth factors.

In vitro and in vivo studies have shown that 1α,25-dihydroxyvitamin D3 [1,25(OH)2D3] inhibits angiogenesis in cancer. We now examined whether the antiangiogenic effects of 1,25(OH)2D3 are mediated by the hypoxia-inducible factor (HIF)-1 pathway. Our results showed that 1,25(OH)2D3 reduces the protein expression of both the regulated HIF-1α subunit and the vascular endothelial growth factor (VEGF) in various human cancer cells. 1,25(OH)2D3 also inhibited HIF-1 transcriptional activity (measured by reporter gene assay) as well as HIF-1 target genes, including VEGF, ET-1, and Glut-1. We also showed that 1,25(OH)2D3 inhibits cell proliferation under hypoxia. Using HIF-1α knockout colon cancer cells, we show that the inhibition of the hypoxia-induced VEGF by 1,25(OH)2D3 is mediated through a HIF-dependent pathway. Because HIF-1 is a major positive contributor in human tumorigenesis and angiogenesis, we believe that its inhibition by 1,25(OH)2D3 strengthens the rationale to use vitamin D and its low-calcemic analogues in cancer chemoprevention and therapy. [Mol Cancer Ther 2007;6(4):1433–9]

The article addresses the clinical query whether a casual determination of 24-hour urinary calcium excretion by the end of first-year treatment with alendronate in osteoporotic postmenopausal women correlates with the change in bone mineral density achieved during that year. The study included 2 arms: a prospective arm (n = 31) with women on long-term hormone replacement therapy were followed for 1 year after addition of alendronate (10 mg/daily); a retrospective arm (n = 33) with women using alendronate for 1 year. Bone mineral density and urine deoxypyridinoline were measured at baseline and 1 year, 24-hour urine calcium was obtained at 1 year. All patients used supplemental calcium, but the exact intake values were not determined. The results demonstrated no correlation between the annual increase in both spine and femur bone density and urinary calcium. Assuming that urinary calcium correlates with calcium intake and absorption, a casual measurement of urinary calcium excretion seems irrelevant for the titration of optimal calcium supplementation in this clinical setup.

aMeyer Children Hospital, Haifa, Israel; bMarmara University, Istanbul, Turkey; cUniversity of North Carolina, Chapel Hill, N.C., USA; dVrije Universiteit, Amsterdam, The Netherlands; eAcademic Hospital V.V.B., Brussels, Belgium; fJohns Hopkins University, Baltimore, Md., USA; gBirmingham Children’s Hospital, Birmingham, UK; hUniversitatskinderklinik, Cologne, Germany; iDana Children’s Hospital, Tel Aviv, Israel; jKaplan Hospital Rehovot, Israel

In vitro studies and animal experiments suggest that the production of 1,25-dihydroxyvitamin D [1,25-(OH)(2)D] and 24,25-(OH)(2)D is reciprocally controlled by 1,25-(OH)(2)D. To investigate the role of the vitamin D receptor (VDR) in controlling vitamin D metabolism in humans, we studied 10 patients with vitamin D-dependent rickets type II due to a defective VDR. After a period of high dose calcium therapy, 7 of the patients had normal serum calcium, phosphorus, alkaline phosphatase, and plasma PTH levels (PTH-N), and 3 showed increased serum alkaline phosphatase and plasma PTH (PTH-H). Serum calcium, phosphorus, alkaline phosphatase, PTH, vitamin D metabolites, urinary calcium/creatinine, and renal phosphate threshold concentration were compared with unaffected family members that comprised the control group. Vitamin D metabolites were measured before and after an oral load of 50,000 U/m(2) cholecalciferol. Compared with the control group, 1,25-(OH)(2)D levels were significantly higher and 24,25-(OH)(2)D levels were lower in the PTH-N group and even more so in the PTH-H group. 1alpha-Hydroxylase (1-OHase) and 24-OHase activities were estimated by the product/substrate ratio. In the PTH-N group, 1-OHase activity was higher and 24-OHase activity was lower than in controls. In the PTH-H group, 1-OHase activity was even higher, probably due to an additive effect of PTH. Thus, 1,25-(OH)(2)D-liganded VDR is a major control mechanism for vitamin D metabolism, and PTH exerts an additive effect. Assessment of the influence of 1,25-(OH)(2)D shows reciprocal control of enzyme activity in man, suppressing 1-OHase and stimulating 24-OHase activity.

We have established previously that rat bone tissue, as well as rat and human-derived bone cells in culture, show a sex-specific response to gonadal steroids in stimulation of the specific activity of the BB isozyme of creatine kinase (CK) and DNA synthesis. This response could be modified by manipulation of the endocrine environment during early stages in rat development. To further examine the influence of changing hormonal steroid milieu and vitamin D status on the action of gonadal steroids in developing bone tissue, we used two models of ectopic bone formation: demineralized tooth matrix (DTM) implanted under the skin, and femoral bone marrow (BM) transplanted under the kidney capsule of a syngeneic recipient mouse. The response to gonadal steroids in ossicles developed from implanted DTM depended on the recipient's gender; injection of estradiol 17beta (E2; 5 microg) into young female mice 21 days after DTM implantation increased, 24 h later, CK activity in the newly formed ossicles by approximately 60%, whereas injection of dihydrotestosterone (DHT; 50 microg) had no effect on CK activity. In contrast, in male mice, DHT but not E2 increased CK activity in the ossicles by approximately 50%. This sex-specific response was abolished in gonadectomized mice resulting in a similar response of the ossicles to both E2 and DHT. When DTM was implanted into vitamin D- deficient female mice, there was a lower basal CK activity and a significantly diminished response to E2 in the newly formed bone tissues. When BM, which contains mesenchymal and stromal cells and committed osteoprogenitor cells, was transplanted into 6-week-old intact or gonadectomized female or male mice, the response of the newly formed bone ossicles, 21 days after transplantation, to E2 or to DHT was according to the gender of the donor. Bone formed from BM obtained from female mice responded to E2 only and those formed from male BM responded to DHT only. Ossicles developed from BM obtained from gonadectomized mice showed lack of response to either gonadal steroid. Furthermore, only approximately 25% of the BM transplants obtained from castrated (CAST) male donors developed into ossicles. Ossicles formed from BM obtained from vitamin D-deficient female donors showed lack of response to gonadal steroids. These findings suggest that the manipulation of the hormonal milieu in early stages of the differentiation sequence of bone cells modifies the subsequent selective responsiveness of the developing bone tissue to gonadal steroids.

Pseudohypoparathyroidism type Ia (PHP-Ia) is a hereditary disease characterized by resistance to PTH and other hormones that act via cAMP. Patients have deficient activity of Gs alpha, the alpha subunit of the G protein, which couples hormone receptors to stimulation of adenylate cyclase. We describe two new mutations discovered in two sporadic patients with PHP-Ia. Using genomic DNA, we have amplified exons 2-13 of the Gs alpha gene (GNAS1) by PCR, and sequenced the resulting products. Both patients had Albright's hereditary osteodystrophy, resistance to multiple hormones, and deficient Gs alpha activity. In the first patient, a deletion of a C in exon 5 at codon 115 was found. In the second patient, an insertion of a C in exon 10 at codon 267 was detected. Both these heterozygous mutations cause frameshift, and predict decreased production of Gs alpha. This report adds two new Gs alpha mutations to the known ten mutations recently described.

Dvir R, Golander A, Jaccard N, Yedwab G, Otremski I, Spirer Z, Weisman Y. Amniotic fluid and plasma levels of parathyroid hormone-related protein and hormonal modulation of its secretion by amniotic fluid cells. Eur J Endocrinol 1995;133:277–82. ISSN 0804–4643 Parathyroid hormone-related (PTHrP), the major mediator of humoral hypercalcemia of malignancy, may also regulate placental calcium flux, uterine contraction and fetal tissue development. In the present study, we demonstrated that the mean immunoreactive PTHrP concentrations in amniotic fluid at mid-gestation (21.2 ± 3.7 pmol/l) and at term (19.0 ± 2.7 pmol/l) were 13-16-fold higher than levels measured in either fetal (1.6 ± 0.1 pmol/l) or maternal plasma (1.4 ± 0.3 pmol/l) at term and equal to levels found in plasma of patients with humoral hypercalcemia of malignancy. In vitro studies pointed to three possible sources of PTHrP in amniotic fluid: cultured amniotic fluid cells, cells derived from the amniotic membrane overlying the placenta and placental villous core mesenchymal cells. Treatment of cultured amniotic fluid cells with human prolactin, human placental lactogen (hPL) or human growth hormone (100 μg/l) increased PTHrP secretion after 24 h by 43%, 109% and 90%, respectively. Insulin-like growth factors I and II(100 μg/l), insulin (100 μg/l) and epidermal growth factor (EGF) (10 μg/l) increased PTHrP secretion by 53%, 46%, 68% and 118%, respectively. The stimulation of PTHrP secretion by EGF or by hPL was both time- and dose-dependent. In contrast, calcitriol and dexamethasone (10 nmol/l) decreased PTHrP secretion by 32% and 75%, respectively. Estradiol, progesterone, dihydrotestosterone and human chorionic gonadotropin had no effect on PTHrP secretion. These findings support the notion that PTHrP may play a physiological role in the uteroplacental unit and demonstrate that human amniotic fluid cells could be a useful model for studying the regulation of PTHrP production and secretion by hormones and growth factors. Y Weisman, Bone Disease Unit, Tel Aviv Medical Center, 6 Weizman Street, Tel Aviv 64239, Israel

Administration of GnRH agonist analogs to women may result in a hypoestrogenic state and bone mass reduction. In the present study we examined bone mineral density (BMD) and parameters of mineral metabolism in elderly men with benign prostatic hyperplasia before and during a hypoandrogenic state induced by the long-acting GnRH agonist D-Trp6-LHRH (decapeptyl). Our results showed that decapeptyl treatment caused a significant decrease in serum testosterone concentrations in all patients and resulted in a significant decrease in individual vertebral BMD in 10 of 17 patients. A significant decrease in BMD was observed in 5 patients after 6 months of treatment. Another 5 patients showed a decreased BMD only after 12 months. The mean serum concentrations of osteocalcin, phosphorus, and alkaline phosphatase activity increased after 6-12 months of treatment with decapeptyl. Serum calcium, vitamin D metabolites, and PTH concentrations remained unchanged during treatment. Urinary calcium excretion was slightly, but not significantly, increased after 6 months of treatment. These results demonstrate that long-acting GnRH agonist treatment may cause high turnover accelerated bone loss in some men during the first year of GnRH agonist treatment, as has been previously shown in women.

OBJECTIVE Since it is not clear whether testosterone or dihydrotestosterone is the active hormone in bone metabolism, we wished to assess the effect of finasteride, a 5α-reductase inhibitor, on vertebral bone mineral density and parameters of bone and mineral metabolism. DESIGN Patients were treated in a randomized, double-blind controlled study with either placebo, 1 or 5 mg/day finasteride. PATIENTS Twenty-three men with benign prostatic hyper-plasla (BPH) were included in this study; eight received placebo, seven were allocated to treatment with 1 mg/day, and eight to 5 mg/day finasteride for 12 months. MEASUREMENTS Vertebral bone mineral density was measured at the lumbar spine by dual energy X-ray bone densltometry. Serum calcium, phosphorus, parathyroid hormone, osteocalcln and vitamin D metabolites were measured regularly. Urinary calcium and creatinlne excretion were monitored as well. RESULTS Finasteride caused a significant decrease in serum dlhydrotestosterone after 6 and 12 months, but no effect on serum testosterone. Vertebral bone mineral density remained unaltered. None of the other parameters monitored were affected except for a small unexplained increase in 1,25-dihydroxyvitamin D in the group receiving 5 mg finasteride/day. CONCLUSIONS Testosterone is probably the active hormone in bone metabolism. However, oestradiol, the product of testosterone aromatization (which remains unaltered under finasteride) may yet be another possible responsible steroid in the maintenance of bone density. We can also not rule out that the small amount of dihydrotestosterone remaining under finasteride administration is sufficient for maintaining normal bone metabolism.

We have demonstrated previously that 17β-estradiol (E 2 ) stimulates cell proliferation in skeletal tissues, as measured by increased DNA synthesis and creatine kinase (CK) specific activity, and that calciotrophic hormones modulate E 2 activity in rat osteoblastic sarcoma cells (ROS 17/2.8). Moreover, E 2 failed to stimulate DNA synthesis in vitamin D-depleted female rat bone in the absence of prior i.p. injections of 1,25(OH) 2 D 3 . We have, therefore, studied the effects of pretreatment of cells by one hormone on their response to challenge by a second hormone. We now report reciprocal interactions of sex steroids and other hormones modulating bone formation on cell proliferation parameters in primary bone and cartilage cell cultures; these interactions can selectively augment or diminish cell responsiveness to a given hormone. Pretreatment of rat epiphyseal cartilage cell cultures with 1,25(OH) 2 D 3 , 24,25(OH) 2 D 3 or parathyroid hormone (PTH) for 5 days, followed by E 2 treatment for 24 h, resulted in increased DNA synthesis compared to cultures pretreated with vehicle. Prostaglandin (PGE 2 ) pretreatment blocked further response to E 2 . In the reciprocal case, rat epiphyseal cartilage cells, pretreated with E 2 , showed an increased response to PTH, a loss of the response to PGE 2 or 24,25(OH) 2 D 3 and an inhibition of CK activity and DNA synthesis by 1,25(OH) 2 D 3 , similar to the characteristic inhibitory action of 1,25(OH) 2 D 3 in osteoblasts. By contrast, rat epiphyseal cartilage cells pretreated with testosterone showed no changes in response to PTH, 24,25(OH) 2 D 3 or PGE 2 and a decreased response to E 2 , but were stimulated by 1,25(OH) 2 D 3 . Rat embryo calvaria cell cultures behaved similarly to epiphyseal cartilage cultures except that 24,25(OH) 2 D 3 pretreatment did not increase the response to E 2 . Reciprocally, pretreatment with E 2 before exposure to calciotrophic hormones did not change the responses of rat embryo calvaria cell cultures to 1,25(OH) 2 D 3 or 24,25(OH) 2 D 3 . These findings suggest that the mutual interactions between calciotrophic hormones and E 2 , demonstrated here in vitro , could selectively affect the responses of bone and cartilage cells to E 2 by several mechanisms. These possibilities include increased E 2 receptors and E 2 -stimulated differentiation of cartilage cells to more E 2 responsive cells showing some characteristics of osteoblasts.

The recent demonstration of estrogen receptors in bone derived cells has stimulated the study of direct effects of sex steroids on bone. We have shown direct stimulation of proliferation by 17 beta-estradiol (E2) of ROS 17/2.8 rat osteogenic osteosarcoma cells, and other bone-derived cells in culture, as well as sex-specific stimulation of diaphyseal bone in vivo by estrogen and testosterone, using [3H]thymidine incorporation into DNA and stimulation of the specific activity of creatine kinase as markers. ROS 17/2.8 cells were used as models of osteoblast-like cells to study the reciprocal modulation of stimulation of bone cell proliferation by sequential treatment by sex steroid and calciotrophic hormones. Pretreatment with 1,25(OH)2D3 and PTH augmented stimulation by E2, while pretreatment with PGE2 followed by E2 resulted in no additional stimulation. Reciprocally, pretreatment with E2 significantly reduced the response to PGE2 while showing an insignificant effect on the response to the other hormones. Gonadectomized Wistar-derived rats provided a useful model system for study of postmenopausal osteoporosis. In diaphyseal bone, [3H]thymidine incorporation and creatine kinase activity decreased 4 weeks after gonadectomy. At that time, a single i.p. injection of E2 in females, and testosterone in males, resulted in a highly significant increase in both these parameters within 24 h.

Vitamin D-dependent rickets type II (VDDR-II; hereditary resistance to 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]), an autosomal recessive genetic disease that results from a failure to respond to 1,25-(OH)2D3, is characterized by severe rickets, hypocalcemia, growth retardation, and high prevalence of alopecia. We used amniotic fluid cells in the 17th week of gestation to detect VDDR-II in fetuses at risk for the defect. First, we demonstrated in cells obtained from 15 control pregnancies the presence of a specific high affinity 1,25-(OH)2D3 receptor (Kd = 0.3 x 10(-11) mol/L; maximal number of binding sites, 6.1 fmol/mg protein) and 1,25-(OH)2D3-induced 25-hydroxyvitamin D3-24-hydroxylase activity (up to 30-fold increase). Amniotic fluid cells from a woman who had already given birth to a child with VDDR-II contained receptors that bound [3H]1,25-(OH)2D3 normally and responded to 1,25-(OH)2D3 stimulation with a 10-fold increase in 24-hydroxylase activity. The fetus was, therefore, judged unaffected, and a normal baby girl was born. At the age of 16 months she did not demonstrate clinical or biochemical features of VDDR-II. Amniotic fluid cells from another mother of a child with VDDR-II were unable to bind [3H]1,25-(OH)2D3, and the hormone failed to stimulate 24-hydroxylase activity. VDDR-II in this fetus was confirmed after termination of pregnancy by the total inability of 1,25-(OH)2D3 to stimulate 24-hydroxylase activity in tissue explants and cell cultures prepared from the fetus's kidney and skin. In contrast, tissues from dead control fetuses responded to stimulation by 1,25-(OH)2D3 with a 3- to 10-fold increase in 24-hydroxylase activity. Fetal kidney and skin explants and cell cultures also synthesized a [3H]1,25-(OH)2D3-like metabolite from [3H]25-OHD3 as early as the 17th week of gestation. 1,25-(OH)2D3 (10 nM) decreased the in vitro synthesis of the [3H]1,25-(OH)2D3-like metabolite in tissues from dead control fetuses, but not from the affected fetus. Thus, human fetuses at midgestation already have the regulatory mechanisms responsive to 1,25-(OH)2D3 present postnatally. The prenatal diagnosis of VDDR-II is now possible and is indicated in a high risk family.

The present study examined the effect of long-term, moderate physical exercise on trabecular bone volume (TBV), calcium content, 3H-proline uptake, and the activities of alkaline and acid phosphatases in lumbar vertebrae of aging and senescent mice. It became apparent that if physical activity starts at an early stage of life, i.e., prior to middle age and is extended until old age, it exerts beneficial effects on trabecular bone mass and mineralization. Such a positive effect is not obtained if the training program is initiated after middle age. The training-induced reduction in bone loss was accompanied by a significant decrease in acid phosphatase activity whereas no changes took place with regard to the activity of alkaline phosphatase. Long-term physical exercise also enhanced the uptake of 3H-proline by lining cells along the bone trabecules. In spite of its moderate nature, the endured training program served as a stress factor for the involved animals, a fact that was manifested by an increase in the serum levels of corticosterone. Thus, it seems that whereas young animals respond favorably to such a stimulatory stress, older animals lose this ability of adaptation.

The active metabolite of vitamin D, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), has been shown to enhance the growth of human granulocyte/macrophage haemopoietic progenitors in vitro and to induce these cells to differentiate along the monocyte/macrophage pathway. In order to evaluate the relationship between specific receptors for 1,25(OH)2D3 and the role of 1,25(OH2D3 in the regulation of haemopoietic cell differentiation, we examined the effect of haemopoietic cell differentiation, we examined the effect of 1,25(OH)2D3 on the in vitro growth and differentiation patterns of marrow myeloid progenitor cells from two patients with 1,25(OH)2D3 resistant rickets, resulting from defective receptors to vitamin D. A significant rise in the frequency of myeloid colonies in control marrow cell cultures was induced by 2 X 10(-9) to 2 X 10(-7)M 1,25(OH)2D3. This rise reached a plateau at 2 X 10(-9)_2 X 10(-8) M 1,25(OH)2D3, resulting in a maximal 54 +/- 9% increase in colony numbers. In contrast, no stimulatory effect could be detected when 1,25(OH)2D3 was added to cultured marrow cells from the patients with 1,25(OH)2D3 resistance. Analysis of colony composition revealed that 2 X 10(-8) and 2 X 10(-7) M, 1,25(OH)2D3 induced a 50 +/- 26% increase in the frequency of colonies composed only of monocytes/macrophages in control, but not in the patients' marrow cell cultures. The effect of 2 X 10(-8) and 2 X 10(-7) M 1,25(OH)2D3 on progenitor cell differentiation towards monocytes/macrophages was also observed in marrow cell suspension cultures. Whereas 1,25(OH)2D3 induced a 81-136% increase in the frequency of monocytes in control marrow cells, no effect could be detected on the generation of mature monocytes in marrow cells of the 1,25(OH)2D3 resistant patients. Our results show that marrow granulocyte/macrophage progenitor cells from patients with 1,25(OH)2D3 resistance fail to respond to 1,25(OH)2D3. We thus demonstrate that the effect of 1,25(OH)2D3 on the proliferation and differentiation of haemopoietic progenitor cells is mediated through its binding to specific cytoplasmic receptors.

Two unrelated kindreds with four affected children having 1,25-dihydroxyvitamin D resistance, rickets, and alopecia are described. The children exhibited early onset of severe rickets with hypocalcemia, hypophosphatemia, elevated serum alkaline phosphatase levels, and secondary hyperparathyroidism. Radiography showed diffuse demineralization and classic changes of rickets. All affected children had total-body alopecia. Serum levels of 1,25-dihydroxyvitamin D3 were elevated and rose to extremely high values during treatment, with no apparent change in the mineral disorder. However, secondary hyperparathyroidism and hypophosphatemia did remit during treatment despite persistently low calcium levels. Skin biopsy was performed in the parents and affected children in one kindred. Analysis of 1,25-dihydroxyvitamin D3 receptors in cultured fibroblasts indicated apparent normal receptors in the parents and undetectable receptors in both affected children. After long periods of treatment with vitamin D metabolites and mineral replacement, healing took place in the older child in each kindred. These data suggest that the healing occurred spontaneously as the children reached seven to nine years of age rather than as a result of the treatment. The biochemical lesion in these children appeared to be a genetically transmitted defect in the 1,25-dihydroxyvitamin D3 receptor. The mechanisms by which healing was initiated and maintained remain to be elucidated.

Serum 25-hydroxyvitamin D (25-OHD) levels were measured in 338 elderly patients admitted to the Geriatric Medicine Departments of a general hospital in Israel in the course of one year. The mean (+/- SD) serum 25-OHD levels were significantly lower (P less than .01) in the elderly patients (13.5 +/- 8.9 ng/mL) than in healthy young controls (24.7 +/- 6.1 ng/mL). One hundred ten patients (35.5%) were either vitamin D deficient (25-OHD less than 5 ng/mL) or had borderline serum levels of 25-OHD (5-9 ng/mL). The mean (+/- SD) serum 25-OHD concentration of patients who were completely mobile before hospitalization was 15.5 +/- 8.8 ng/mL (n = 239). In patients mainly immobilized but able to leave the house occasionally, it was 10.2 +/- 6.3 ng/mL (n = 84) and of bed-ridden patients, it was 5.2 +/- 3.2 ng/mL (n = 15). No correlation was found between serum 25-OHD levels and the patients' age or serum calcium, phosphorus, alkaline phosphatase, and albumin values. Thus, in order to detect vitamin D deficiency in the elderly, it is necessary to measure serum 25-OHD concentration. The results demonstrate that vitamin D deficiency is common among elderly patients even in sunny climates and indicate the need for development of effective programs of prevention and treatment.

The concentrations of unconjugated 25-OHD, 24, 25(OH)2D, and 1,25(OH)2D were measured in human milk by competitive protein-binding radioassays following successive preparative Sephadex LH-20 chromatography and HPLC. The mean (+/- SE) concentration of 25-OHD was 0.37 +/- 0.03 ng/ml, of 24,25(OH)2D was 24.8 +/- 1.9 pg/ml, and of 1,25(OH)2D was 2.2 +/-0.1 pg/ml. The concentration of 25-OHD3 in milk as determined by HPLC and UV detection at 254 nm was 0.27 +/- 0.08 ng/ml. The milk concentrations of vitamin D metabolites did not correlate with the maternal serum 25-OHD levels. The total amounts of unconjugated vitamin D metabolites correspond to the known low bioassayable vitamin D antirachitic activity in human milk.

Pregnant rats were maintained on diets either adequate or deficient in vitamin D. On the 20th day of gestation, animals were either nephrectomized bilaterally or sham operated. Immediately therafter, four groups of nephrectomized or sham-operated pregnant rats received iv [26,27-3H]25-hydroxyvitamin D3 ([26,27-3H]25OHD3), while two groups received [1,2-3H,4-14C]D3. The animals were sacrificed 10-24 h later. The distribution of the radiolabeled metabolites of vitamin D3 was determined in extracts of maternal plasma, maternal intestinal tract, placentae, and fetuses after Sephadex LH-20 column chromatography. Both vitamin D3 and 25OHD3 crossed the placenta and entered the fetus. In anephric animals receiving [26,27-3H]-25OHD3, 24,25-dihydroxyvitamin D and a polar peak eluting in the position of 1,25-dihydroxyvitamin D [1,25(OH)2D] and 25,26-dihydroxyvitamin D were identified in extracts of maternal plasma and intestinal tracts and of placentae and fetuses. The identities of 24,25-dihydroxyvitamin D and 1,25 (OH)2D were confirmed by high pressure liquid chromatography. In rats receiving [1,2-3H,4-14C]D3, approximately 50% of the polar metabolite consisted of 1,25(OH)2D. We conclude that the anephric pregnant rat is able to synthesize 1,25(OH)2D, that the fetal portion of the feto-placental unit is the most likely site of production of this hormone, and that this metabolite of vitamin D is able to cross the placenta from the fetus to the mother.

To characterize the action of hPRL and human placental lactogen on the amnion, decidua and placenta, we examined the effects of these hormones on the brain type isozyme of creatine kinase in cultured explants of these tissues from normal deliveries. In the amnion, hPRL (1 mg/l) caused a 1.8-fold increase in creatine kinase specific activity in 24 h, whereas hGH (1 mg/l) or human placental lactogen (1 mg/l) had no effect; oPRL (1 mg/l) also caused a 2.5-fold increase in creatine kinase activity. Neither hPRL, human placental lactogen nor hGH had a significant effect on creatine kinase activity in the placenta or decidua. [3H]thymidine incorporation into DNA increased in parallel to the stimulation of creatine kinase activity. The predominant isozyme of creatine kinase in both the unstimulated and stimulated explants was the brain type isozyme. Creatine kinase activity in the amniotic tissue increased significantly 2 h after hPRL treatment and reached its highest value at 4 h. The enzyme activity in the amnion rose with increasing hPRL dose and showed a significant increase at physiologic concentrations as low as 0.01 mg/l. This study, therefore, provides evidence for biological action of prolactin in amniotic tissue, suggesting that the amnion is physiologically responsive to prolactin.

We have demonstrated that epiphyseal chondroblasts contain specific receptors for 24R,25-dihydroxy vitamin D3(24,25(OH)2D3) while diaphyseal osteoblasts contain specific receptors for 1α25-dihydroxy vitamin D3(1,25(OH)2D3). Both metabolites induce DNA synthesis and creatine kinase (CKBB) activity. We have also found that the responsiveness of rat kidney to these metabolites changes during development. In embryonic and early postnatal stages, the kidney responds to 24,25(OH)2D3, later to both 24,25(OH)2D3 and 1,25(OH)2D3, and the mature kidney only to 1,25(OH)2D3. These responses correlate with changes in the specific receptors present in the kidney. Furthermore, we have compared developmental changes in skeletal (epiphysis, diaphysis and mandibular condyle) and non-skeletal (kidney, cerebellum, cerebrum, liver and pituitary) tissue in both rat (a postnatal developer) and rabbit (a perinatal developer). Epiphyseal or diaphyseal chondroblasts at any stage of development were predominantly responsive to 24,25(OH)2D3, whereas osteoblasts were responsive to 1,25(OH)2D3. In contrast, condylar chondroblasts, kidney, cerebellum and pituitary responded to 24,25(OH)2D3 during early development and subsequently developed responsiveness to 1,25(OH)2D3. Using primary cell cultures from kidneys at different stages of maturation, we showed the same developmental pattern as in vivo. Chronic treatment of the cells with 24,25(OH)2D3, but not 1,25(OH)2D3, caused precocious development of responsiveness to 1,25(OH)2D3 in culture. We suggest that 24,25(OH)2D3 acts as a maturation factor, during early development in kidney, and probably in other tissues, possibly by induction of receptor to 1,25(OH)2D3, accompanied by down-regulation of its own receptor.

There is emerging evidence for specific binding sites and biologic action for 24,25(OH)2D3 in the epiphyseal cartilage. The present study was undertaken to identify the target cells of 24,25(OH)2D3 in the epiphyses of rat bone using an autoradiographic technique. Pieces of epiphyseal cartilage obtained from 4-day-old vitamin D-deficient rats were incubated for 15 or 60 min with [3H]-24,25(OH)2D3 in the presence or absence of 100-fold excess of 25(OH)D3, 1,25(OH)2D3, or 24R,25(OH)2D3. The pieces were prepared for autoradiographic study by a new modified fixation method. Cytoplasmic and nuclear concentration of radioactivity was observed in all cell layers of the epiphyseal cartilage except for the hypertrophic cartilage zone. The highest concentration of radioactivity was seen in the proliferating chondroblasts of the columnar zone. After 15 min of incubation the radioactivity was seen mainly in the cell membrane and cytoplasm, whereas at 60 min radioactivity was also prominent in the nuclei. The competition with excess of cold metabolites revealed that only 24R,25(OH)2D3 caused a significant decrease in cytoplasmic and nuclear radioactivity. These data support the biochemical studies showing that the epiphyseal cartilage is a target tissue for 24,25(OH)2D3.

A direct in vitro effect of 17 beta-estradiol (E2) was demonstrated on bone and cartilage cell energy metabolism. Sex-specific stimulation by E2 and testosterone was shown in diaphyseal bone of weanling rats. E2 (30 nM) caused, within 24 hr, a 70-200% increase in creatine kinase (CK; ATP:creatine N-phosphotransferase, EC 2.7.3.2) specific activity in ROS 17/2.8 rat osteogenic sarcoma cells, MC3T3-E1 mouse calvaria-derived cells, and rat fetal calvaria cells, and a 40% increase in rat epiphyseal cartilage cells. Stimulation of CK activity by E2 was dose and time dependent: in ROS 17/2.8 cells, a highly significant increase was found at 3 nM E2 and a greater than 100% increase in CK activity was found 1 hr after E2 administration. In female 20-day-old Wistar-derived rats, E2 (5 micrograms per rat) increased CK activity in diaphyseal bone by 82% within 1 hr of i.p. injection, with a maximal increase of 200% after 24 hr; neither the weakly estrogenic agonist 17 alpha-estradiol, testosterone, nor progesterone showed this effect. Conversely, in male rat diaphyseal bone, testosterone or dihydrotestosterone increased CK activity after 24 hr by approximately 100%, while E2 was ineffective. In epiphyseal cartilage, both E2 and testosterone increased CK activity. Stimulation of CK activity by sex hormones was paralleled by significant increases in [3H]thymidine incorporation into DNA. Therefore, it is possible that direct sex-specific actions of gonadal steroids may contribute to stimulating bone growth and maintaining balanced bone turnover.

We have previously demonstrated that gonadal steroids stimulate [3H]thymidine incorporation and creatine kinase specific activity in skeletal tissues. In the present study we report that in 20-day-old vitamin D-deficient Wistar-derived rats, 17 beta-estradiol (E2; 5 micrograms/rat) or testosterone (50 micrograms/rat) failed to stimulate [3H]thymidine incorporation into diaphyses of long bones and that the response to these hormones in terms of increased creatine kinase specific activity was less than half the value in normally fed rats. Two daily ip injections of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3; 0.5 ng/g BW], but not 24,25-(OH)2D3 (5 ng/g BW), partially restored the biological responses to E2 in bone of 21-day-old vitamin D-deficient female rats. Vitamin D deficiency did not impair the responsiveness to gonadal steroids in the epiphysis of long bones, uterus, or prostate, in contrast to its effect on diaphysis. In 21-day-old normally fed female rats, neither vitamin D metabolite enhanced the response to E2. When cultures of rat epiphyseal cells were treated daily for 5 days with either 1,25-(OH)2D3 (1 nM) or 24,25-(OH)2D3 (10 nM), followed by E2 (30 nM) for 24 h, creatine kinase activity was significantly higher than in cultures treated daily for 5 days with vehicle alone, and then with E2. The same treatment of rat embryo calvaria bone cells showed that 1,25-(OH)2D3, but not 24,25-(OH)2D3, significantly increased the creatine kinase activity response to E2. These findings suggest that vitamin D metabolites selectively affect the biological responses of skeletal tissues to gonadal steroids.

To provide further data on vitamin D metabolism in pregnancy, the concentrations of 25-hydroxyvitamin D (25OHD; n = 72), 24,25-dihydroxyvitamin D [24,25-(OH)2D; n = 70], and 1,25-(OH)2D (n = 59) were measured in amniotic fluid by competitive protein-binding radioassays. At term, the mean (+/- SE) concentrations of 25OHD and 24,25-(OH)2D in amniotic fluid (810 +/- 76 and 37.5 +/- 5.4 pg/ml, respectively) were significantly lower (P less than 0.01) than those at 16-18 weeks gestation (1707 +/- 2.67 and 149 +/- 3 pg/ml, respectively). Similarly, the concentrations of 25OHD in pooled amniotic fluid samples, as determined by high pressure liquid chromatography and UV absorbance detection at 254 nm, were 664 +/- 188 pg/ml at term and 1240 +/- 294 pg/ml at midgestation. In comparison, no difference could be found between the mean concentrations of 1,25-(OH)2D at term (4.3 +/- 0.8 pg/ml) and those at midgestation (3.3 +/- 0.4 pg/ml). However, in 14 of 39 amniotic fluid samples obtained at term (35.9%), the concentration of 24,25-(OH)2D was undetectable, while the level of 1,25-(OH)2D was increased. The reciprocal relationship between 24,25-(OH)2D and 1,25-(OH)2D found in more than a third of the amniotic fluid samples at term may be due to a regulatory mechanism responding to the increased fetal demand for calcium in the final stages of pregnancy.

may signal the invasiveness of an amp-R strain that previously was carried only in the nasopharynx. Whether it would prove useful to monitor throat or nasopharyngeal cultures obtained from patients with H. influenzae type b meningius prior to initiating antibiotic therapy is unknown In the laboratory the presence of a heterogeneous population ofH. influenzae type b creates the potential for reports of false sensitivity to ampicillin. When the KirbyBauer disc method is utilized, agar plates must be inspected carefully for the presence of "breakthrough" colonies within the 20-mm zone of inhibition. 1 It also seems possible that. on rare occasions, only amp-S colonies could be subcultured from the original culture to sensitivity plates or utilized for the beta-lactamase assay. Furthermore. if the clinical isolate contains a small percentage of amp-R colonies, the color change may not be easily observed in the one-minute beta-lactamase test. since this reqmres greater than 97 units of penicillinase. 7 REFERENCES 1. Gray BM, Hubbell CA, and Dillon HD: Manner and meaning of susceptibility testing of ampicillin resistant