Inactivating mutations in the 25-hydroxyvitamin D3 1alpha-hydroxylase gene in patients with pseudovitamin D-deficiency rickets.

BACKGROUND: Pseudovitamin D-deficiency rickets is characterized by the early onset of rickets with hypocalcemia and is thought to be caused by a deficit in renal 25-hydroxyvitamin D3 1alpha-hydroxylase, the key enzyme for the synthesis of 1alpha,25-dihydroxyvitamin D3. METHODS: We cloned human 25-hydroxyvitamin D3 1alpha-hydroxylase complementary DNA (cDNA) using a mouse 1alpha-hydroxylase cDNA fragment as a probe. Its genomic structure was determined, and its chromosomal location was mapped by fluorescence in situ hybridization. We then identified mutations in the 1alpha-hydroxylase gene in four unrelated patients with pseudovitamin D-deficiency rickets by DNA-sequence analysis. Both the normal and the mutant 1alpha-hydroxylase proteins were expressed in COS-1 cells and were assayed for 1alpha-hydroxylase activity. RESULTS: The gene for 25-hydroxyvitamin D3 1alpha-hydroxylase was mapped to chromosome 12q13.3, which had previously been reported to be the locus for pseudovitamin D-deficiency rickets by linkage analysis. Four different homozygous missense mutations were detected in this gene in the four patients with pseudovitamin D-deficiency rickets. The unaffected parents and one sibling tested were heterozygous for the mutations. Functional analysis of the mutant 1alpha-hydroxylase protein revealed that all four mutations abolished 1alpha-hydroxylase activity. CONCLUSIONS: Inactivating mutations in the 25-hydroxyvitamin D3 1alpha-hydroxylase gene are a cause of pseudovitamin D-deficiency rickets.

The effect of CV-3988 and CV-6209 on the acute gastric erosions of rats due to water-immersion and restraint stress.

CV-3988 and CV-6209 inhibited gastric erosions in rats due to water-immersion and restraint stress in a dose-dependent manner. The above inhibitory effects of CV-3988 were observed in the presence of indomethacin, which may indicate that the inhibition is not prostaglandin dependent. The studies indicate that platelet-activating factor may be involved in the formation of erosions in rats under water-immersion and restraint stress.

Experimental hypersensitivity pneumonitis in the mouse: histologic and immunologic features and their modulation with cyclosporin A.

A murine model of hypersensitivity pneumonitis (HP) was established with transnasally administered Thermoactinomyces vulgaris (Tv) bacilli. Bronchoalveolar lavage (BAL) of experimental animals revealed marked increase in the total cell, lymphocyte, and macrophage numbers; the findings were similar to those in human HP. The BAL lymphocytes were mostly Thy 1.2 positive. Lyt-1 positive cells predominated Lyt-2 positive cells. Anti-Tv IgG antibodies and delayed-type hypersensitivity footpad reactions against Tv were detected in animals with HP. Cyclosporin A (CyA), a potent immunosuppressive drug, had marked effects on the development of HP in this model. When CyA was administered throughout the course of Tv inoculations, the granulomatous pneumonitis was markedly suppressed, and an increase in BAL lymphocytes, Thy 1.2 positive cells, was suppressed. When CyA was administered only during the first half period of the Tv treatment, suppression of the disease was minimal; when CyA was administered in the latter half, both the HP lesions and the increase in BAL cell lymphocyte numbers were significantly suppressed. These results indicate that a series of transnasal administration of Tv in mice may provide a good model for human HP.