Suppression of the dwarf phenotype of an Arabidopsis mutant defective in thermospermine biosynthesis by a synonymous codon change in the SAC51 uORF

Thermospermine plays a critical role in negatively regulating xylem development in angiosperms. A mutant of Arabidopsis thaliana that is defective in thermospermine biosynthesis, acaulis5 (acl5), exhibits a dwarf phenotype with excessive xylem formation. Mechanistically thermospermine acts in attenuating the inhibitory effect of an evolutionarily conserved upstream open reading frame (uORF) on the main ORF of SAC51, which encodes a basic helix-loop-helix protein involved in xylem repression. Here, we revealed that a semidominant suppressor of acl5, sac503, which partially restores the acl5 phenotype, has a point mutation in the conserved uORF of SAC51 with no amino acid substitution in the deduced peptide sequence. In transgenic lines carrying the β-glucuronidase (GUS) reporter gene fused with the SAC51 5' region containing the uORF, the mutant construct was shown to confer higher GUS activity than does the wild-type SAC51 construct. We confirmed that sac503 mRNA was more stable than SAC51 mRNA in acl5. These results suggest that the single-base change in sac503 positively affects the translation of its main ORF instead of thermospermine. We further found that the uORF-GUS fusion protein could be synthesized in planta from the wild-type and sac503 translational fusion constructs.

Effects of mechanical stress and deficiency of dihydrotestosterone or 17β-estradiol on Temporomandibular Joint Osteoarthritis in mice

OBJECTIVE

To observe and analyze the interaction between excessive mechanical stress (MS) and decreased sex hormones on Temporomandibular Joint Osteoarthritis (TMJ-OA), and to discover TMJ-OA disease susceptibility genes by molecular biological analysis to elucidate part of the mechanism of TMJ-OA onset.

DESIGN

For experimental groups, orchiectomy (ORX) or ovariectomy (OVX) was performed on sexually mature 8-week-old mice. A metal plate was attached to the posterior surface of the maxillary incisors to apply excessive MS on mandibular condyles. Male mice were divided into control, ORX, MS, and ORX + MS groups, while female mice were divided into control, OVX, MS, and OVX + MS groups. Mandibular condyles were evaluated by histology and molecular biology.

RESULTS

Histomorphometric analysis of the TMJ in ORX + MS and OVX + MS groups revealed the thinnest chondrocyte layers, highest modified Mankin scores, and significant increases in the number of osteoclasts. Gene expression analysis indicated upregulation of Angptl7 and Car1 genes in the mandibular condyles of mice subjected to the combined effects of excessive MS and reduced sex hormones. In vitro analysis suggested that cartilage-like cells overexpressing Angptl7 enhanced calcification, and osteoblast-like cells overexpression Car1 suppressed cell proliferation and calcification.

CONCLUSIONS

A severe TMJ-OA mouse model was successfully developed by applying excessive MS on the mandibular condyle of male and female mice with reduced sex hormones. Disease-susceptibility genes Angptl7 and Car1 were newly discovered in the experimental groups, suggesting their involvement in the onset mechanism of TMJ-OA.

Easy-to-Use InDel Markers for Genetic Mapping between Col-0 and Ler-0 Accessions of Arabidopsis thaliana

Map-based gene cloning has played a key role in many genetic studies using the model plant, Arabidopsis thaliana. In the post- next generation sequencing era, identification of point mutations and their corresponding genes is increasingly becoming a powerful and important approach to define plant gene function. To perform initial mapping experiments efficiently on Arabidopsis mutants, enrichment of easy-to-use and reliable polymorphic DNA markers would be desirable. We present here a list of InDel polymorphic markers between Col-0 and Ler-0 accessions that can be detected in standard agarose gel electrophoresis.

A novel synthetic vitamin D3 analogue, 2-beta-(3-hydroxypropoxy)-calcitriol (ED-71): its biological activities and pharmacological effects on calcium metabolism

A novel vitamin D3 analogue, [2 beta-(3-hydroxypropoxy)-calcitriol: ED-71] showed a similar Ca-regulating activity as calcitriol in the in vivo and in vitro Ca mobilization test and ex vivo intestinal Ca absorption assay using vitamin D-deficient rats. The differentiation-inducing activity of ED-71 in mouse myeloid leukemia cell line (WEHI-3 cell) was slightly less than that of calcitriol. ED-71 distributes predominantly in plasma as an intact form and its half-life plasma was twice as long as that of calcitriol. Further study revealed that the higher binding potency of ED-71 to plasma-specific vitamin D-binding protein (DBP) compared with that of calcitriol accounts for its stability in the blood circulation. The pharmacological effect of ED-71 for the animal models with osteoporosis seemed to be better than that calcitriol. These results suggest that ED-71 should become a valuable therapeutic long-acting drug for patients with osteoporosis.

The noncalcemic analogue of vitamin D, 22-oxacalcitriol, suppresses parathyroid hormone synthesis and secretion

OCT, a non-calcemic analogue of 1,25(OH)2D3 has been found to have a more potent activity than that of 1,25(OH)2D3 regarding cell differentiation and immunopotentiation activity, and to prolong the average life span of MRL/l mice. Recently, we found that OCT effectively suppressed the secretion and synthesis of PTH without inducing hypercalcemia. In primary cultures of bovine parathyroid cells, OCT was capable of suppressing PTH release in a dose-dependent manner. OCT was also active in vivo, and, like 1,25(OH)2D3, decreased the pre-pro(PTH) mRNA levels. In a group of rats with CRF, daily administration of OCT, 8 ng i.p. for 2 weeks returned PTH levels to normal without changes in serum calcium. Preliminary results in dogs with CRF indicated that after the administration of OCT 5 micrograms i.v., N-terminal PTH decreased by 76% without changes in Ca. In conclusion, OCT may provide a unique contribution to the treatment of secondary hyperparathyroidism.

Metabolism and transporting system of 22-oxacalcitriol

The binding potencies of OCT to chick intestinal calcitriol receptor and vitamin DBP were approximately 1/8 and 1/600 of the respective values of calcitriol. OCT is circulating mainly as an intact form bound to chylomicrons and/or lipoproteins. Intravenously injected [3H]-OCT to normal rats was quickly decreased from blood and rapid excretion of OCT as a glucuronate into bile was observed. However, significant amounts of radioactivities were recovered in the intact form in liver and intestine even after 24 h. The separation of calcemic and immune and/or differentiation activities may be derived from the rapid turnover and the nonspecific transporting system.

Vitamin D and parathyroid hormone degradation by the kidney

Parathyroid function is controlled by the regulation of hormone secretion as well as degradation, through the action of calcium and vitamin D derivatives. In order to clarify the relationship between vitamin D metabolism and parathyroid degradation system, parathyroid hormone (PTH)-degrading activities of the kidney were measured in vitamin D repleted and depleted rats given various derivatives of vitamin D. Kidney calcium content rose markedly in animals given 10 microgram/kg 1 alpha(OH) vitamin D3 and 1,000 microgram/kg dihydrotachysterol and PTH-degrading activity rose only in these animals, indicating a parallelism between kidney calcium content and PTH-degrading activity of the kidney tissue. These vitamin D derivatives also increased the PTH-degrading activity of kidney tissue when they were added in vitro.

Vitamin D and vitamin D dependency

Administration of large doses of vitamin D2 brought about a marked increase of 25-hydroxyvitamin D in both the patients with vitamin D dependency and hypophosphatemic vitamin D-resistant rickets. During the administration of vitamin D2, increment of 1,25-dihydroxyvitamin D was marked in hypophosphatemic vitamin D-resistant rickets, but far smaller in vitamin D dependency. In the latter, however, the 1,25-dihydroxyvitamin D reached the level close to the normal adult values. 1 alpha-hydroxyvitamin D3 was found 50 approximately 100 times as effective as vitamin D2 in 2 patients with vitamin D dependency (optimum maintenance dose: 0.05 micrograms/kg/day). It was concluded that 1 alpha-hydroxylation in the renal tubules is markedly defective in the patients with vitamin D dependency, but that a large dose of vitamin D2 is able to cause a definite increase in serum concentration of 1,25-dihydroxyvitamin D resulting in improvement of the rickets.

Metabolites of 24,25-dihydroxyvitamin D3 made in the kidney of chicks supplemented with vitamin D3

Metabolism of 25-hydroxyvitamin D3 (25-OH-D3) was examined in chicks supplemented with vitamin D3. Kidney homogenates metabolized in vitro [3H]-25-OH-D3 to 3 new metabolites (peaks A, C and E) by way of 24,25-dihydroxyvitamin D3. The enzymes responsible for the synthesis of these metabolites appeared to be induced by 1 alpha,25-dihydroxyvitamin D3. Production of these metabolites was increased in parallel with the increase of the supplemented levels of vitamin D3, while recovery of the radioactivity in the chloroform phase was sharply decreased. The production of peak C was considered to be closely related to the transfer of the radioactive metabolites to the water-soluble phase. These results may indicate that 24-hydroxylation is a degradation step in the 25-OH-D3 metabolism.

Protective role of protein C inhibitor in monocrotaline-induced pulmonary hypertension

BACKGROUND

Protein C inhibitor (PCI) plays a role in multiple biological processes including fertilization, coagulation, fibrinolysis and kinin systems.

OBJECTIVES

We hypothesized that PCI participates in the pathogenesis of pulmonary hypertension. To demonstrate this, we compared the development of pulmonary hypertension in mice overexpressing PCI in the lung with wild-type (WT) mice. Pulmonary hypertension was induced by s.c. injection of 600 mg kg-1 of monocrotaline weekly for 8 weeks.

RESULTS

Right ventricular arterial pressure was significantly increased in monocrotaline-treated WT mice compared with that in monocrotaline-treated transgenic mice. Bronchoalveolar lavage fluid (BALF) levels of thrombin-antithrombin complex, monocyte chemoattractant protein-1 and platelet-derived growth factor, and the plasma level of tumor necrosis factor-alpha were significantly increased in monocrotaline-treated WT mice as compared with monocrotaline-treated PCI transgenic mice. Increased level of PCI-thrombin complex was detected in BALF from monocrotaline-treated PCI transgenic mice as compared with saline-treated PCI transgenic mice.

CONCLUSIONS

This study showed that increased expression of PCI in the lung is protective against monocrotaline-induced pulmonary hypertension, suggesting a potential beneficial effect of PCI for the therapy of this disease.

Biodesulfurization of dibenzothiophene and its derivatives through the selective cleavage of carbon-sulfur bonds by a moderately thermophilic bacterium Bacillus subtilis WU-S2B

Heterocyclic organosulfur compounds such as dibenzothiophene (DBT) in petroleum cannot be completely removed by hydrodesulfurization using chemical catalysts. A moderately thermophilic bacterium Bacillus subtilis WU-S2B, which could desulfurize DBT at 50 degrees C through the selective cleavage of carbon-sulfur (CS) bonds, was newly isolated. At 50 degrees C, growing cells of WU-S2B could degrade 0.54 mM DBT within 120 h to produce 2-hydroxybiphenyl, and the resting cells could also degrade 0.81 mM DBT within 12 h. The DBT-desulfurizing ability of WU-S2B is high over a wide temperature range from 30 to 50 degrees C, and highest at 50 degrees C for both the growing and resting cells, and this is an extremely advantageous property for the practical biodesulfurization. In addition, WU-S2B could also desulfurize DBT derivatives such as 2,8-dimethylDBT, 4,6-dimethylDBT and 3,4-benzoDBT. Therefore, B. subtilis WU-S2B is considered to have more beneficial properties than other desulfurizing bacteria such as Rhodococcus strains previously reported, particularly from the viewpoint of its capacity for thermophilic desulfurization through the CS bond cleavage.

[Recurrent lung cancer with interstitial pneumonia treated with percutaneous radiofrequency ablation]

We performed computed tomography (CT)-guided percutaneous radiofrequency ablation (RFA) for postoperative recurrent pulmonary metastases developed in a 77-year-old man with interstitial pneumonia. He had received left upper segmentectomy with ND 2a nodal dissection. RFA was safely performed for pulmonary metastases in right S6 and left S6. There was no evidence to suggest any deterioration on interstitial pneumonia, including KL 6 and CT findings. Autopsy revealed residual cancer cells in peripheral lesion in 1 of 2 tumors treated by RFA. Although RFA is palliative, it is a promising treatment for local control of pulmonary malignancy in high-risk patients.

History of the development of new vitamin D analogs: studies on 22-oxacalcitriol (OCT) and 2beta-(3-hydroxypropoxy)calcitriol (ED-71)

In 1981 Suda and his colleagues first reported the new activity of calcitriol namely its ability to differentiate the myeloid leukemia cells into normal monocytes-macrophages. However, the possibility of using calcitriol as an antileukemic drug was not feasible because of its potent calcemic effects. Based on these observations, several pharmaceutical companies initiated the synthesis of vitamin D analogs with the aim to separate the calcemic actions of calcitriol from its actions on regulating the cell growth and differentiation. As a result, numerous noncalcemic analogs with a potential for the treatment of leukemia and other cancers were synthesized. The group at Chugai introduced two characteristic analogs of opposite type namely, 22-oxacalcitriol (OCT) and 2beta-(3-hydroxypropoxy)calcitriol (ED-71) which have been shown to have therapeutic value and are already being used clinically. The work on OCT and ED-71 together with the work on calcipotriol and KH-1060 by Leo Laboratories, and 1alpha,25(OH)(2)-16-ene-23-yne-D(3) by Hoffmann-La Roche, vigorously stimulated research world-wide in the development of vitamin D analogs into pharmaceutical products. More recently new impressive vitamin D analogs such as 3-epi analogs, 19-nor analogs, 18-nor analogs, 2-methyl-20-epi-calcitriol, non-steroidal vitamin D analogs are being developed. The authors are convinced that various vitamin D analogs will become highly effective therapeutic agents at the clinical level in the new century, and also that a new theory on the mechanism of vitamin D action will be generated.

Synthesis and stereostructure-activity relationship of three asymmetric center pyrethroids: 2-methyl-3-phenylcyclopropylmethyl 3-phenoxybenzyl ether and cyanohydrin ester

2-Methyl-3-phenylcyclopropylmethyl 3-phenoxybenzyl ether 2 and cyanohydrin ester 3, a couple of pyrethroids with three asymmetric centers, were synthesized. Of each of the four diastereomers of 2 and 3, only the (1R*,2R*,3R*)-2a and 3a showed significant insecticidal activities. Dual sets of enantiomers [(1R,2R,3R)-(-)-2a and (1S,2S,3S)-(+)-2a] and [(1R,2R,3R)-(-)-3a and (1S,2S,3S)-(+)-3a] were synthesized through the asymmetric cyclopropanation using the Aratani catalyst. Significant separations of insecticidal activities were observed between both the enantiomers against the tobacco cutworm (Spodoptera litura) and the common mosquito (Culex pipiens pallens); (1S,2S,3S)-(+)-2a and (+)-3a showed higher activities than their antipodes (1R,2R,3R)(-)-2a and (-)-3a. This result is the second example of such synthetic pyrethroids with three asymmetric centers.

Synthesis and pharmacokinetics of 1 alpha-hydroxyvitamin D3 tritiated at 22 and 23 positions showing high specific radioactivity

A novel synthesis of a radioactive compound of 1 alpha-hydroxyvitamin D3 (1 alpha OHD3) (1) and its pharmacokinetics are described. Radioactive 1 alpha OHD3 tritiated at 22 and 23 positions ([22,23-(3)H4]1 alpha OHD3) (5) was prepared via key reactions of the reduction of acetylenic side chain in the ketone (12) with tritium gas in the presence of palladium-charcoal and the subsequent Wittig reaction with the A-ring synthon (16). [22,23-(3)H4]1 alpha OHD3 (5) showed high specific radioactivity (111.5 Ci/mmol) and was used successfully in pharmacokinetics studies with rats. In the pharmacokinetics studies, the plasma concentration level of the active form of vitamin D3, 1 alpha,25-dihydroxy-vitamin D3 [1 alpha,25(OH)2D3], after oral or intravenous administration of [22,23-(3)H4]1 alpha OHD3 (5), showed longer half-life, lower maximum concentration, and lower area under the curve than those after treatment of 1 alpha,25(OH)2D3 tritiated at 26 and 27 positions (4). These results might suggest a beneficial therapeutic utility of 1 alpha OHD3 (1) over the treatment of 1 alpha,25(OH)2D3 (2).

CROP/Luc7A, a novel serine/arginine-rich nuclear protein, isolated from cisplatin-resistant cell line

A novel putative SR protein, designated cisplatin resistance-associated overexpressed protein (CROP), has been cloned from cisplatin-resistant cell lines by differential display. The N-half of the deduced amino acid sequence of 432 amino acids of CROP contains cysteine/histidine motifs and leucine zipper-like repeats. The C-half consists mostly of charged and polar amino acids: arginine (58 residues or 25%), glutamate (36 residues or 16%), serine (35 residues or 15%), lysine (30 residues, 13%), and aspartate (20 residues or 9%). The C-half is extremely hydrophilic and comprises domains rich in lysine and glutamate residues, rich in alternating arginine and glutamate residues, and rich in arginine and serine residues. The arginine/serine-rich domain is dominated by a series of 8 amino acid imperfect repetitive motif (consensus sequence, Ser-Arg-Ser-Arg-Asp/Glu-Arg-Arg-Arg), which has been found in RNA splicing factors. The RNase protection assay and Western blotting analysis indicate that the expression of CROP is about 2-3-fold higher in mRNA and protein levels in cisplatin-resistant ACHN/CDDP cells than in host ACHN cells. CROP is the human homologue of yeast Luc7p, which is supposed to be involved in 5'-splice site recognition and is essential for vegetative growth.

Three cases of pustulotic arthro-osteitis associated with episcleritis

Three cases of pustulotic arthro-osteitis (PAO) associated with episcleritis were described. In each patient, the episcleritis developed more than 10 years after the onset of PAO. These episcleritis were treated with topical corticosteroids. PAO is classified as a member of the seronegative spondylarthritis group of diseases. Though complications of seronegative spondylarthritis include uveitis and episcleritis. PAO associated with episcleritis was not reported. Episcleritis should be considered as a complication of PAO.

Sustained osteoblast nuclear receptor binding of converted 1alpha, 25-dihydroxyvitamin D3 after administration of 3H-1alpha-hydroxyvitamin D3: a combined receptor autoradiography and radioassay time course study with comparison to 3H-1alpha, 25-dihydroxyvitamin D3

The present study was undertaken to clarify the receptor distribution and the pharmacokinetics of 3H-1alpha(OH)D3, and 3H-1alpha,25(OH)2D3 for comparison. Receptor autoradiography was used after intravenous injection to 3-day-old neonatal rats and radioassay-HPLC after oral application to young adult rats. Corresponding results were obtained from both receptor autoradiography and radioassay. After 3H-1alpha(OH)D3 administration, uptake was delayed but sustained over a long period of time and the concentration of silver grains (autoradiography) or recovered 3H-1alpha,25(OH)2D3 (radioassay) peaked at a lower level. After 3H-1alpha,25(OH)2D3 administration, osteoblast nuclear, whole bone uptake and retention of radiolabeled compound were relatively rapid and short in duration. Nuclear uptake in osteoblasts after administration of 3H-1alpha(OH)D3 was abolished in competition studies with 10-fold unlabeled 1alpha,25(OH)2D3. These results indicate that 1alpha(OH)D3 continuously supplies osteoblasts with converted 1alpha,25(OH)2D3 and would not spread to the cells because of the low binding affinity of the receptor. Accordingly, 1alpha(OH)D3 appears to have some therapeutic properties different from 1alpha,25(OH)2D3 because of a relatively slow and sustained accumulation of the receptor and less Cmax (pharmacokinetics) compared with 1alpha,25(OH)2D3.

Sarcomatoid renal cell carcinoma with widespread metastases to liver and bones in a kidney transplant recipient

A case of sarcomatoid renal cell carcinoma with widespread metastases to liver and bones in a cadaver renal transplant recipient is reported in this article. The patient underwent a kidney transplant at the age of 43 and was treated with various immunosuppressive agents after surgery. Twelve months after the transplantation, multiple tumors were found in the liver, and the patient died 8 months later. Pathological examination at autopsy revealed renal cell carcinoma with a sarcomatoid component in the right native kidney and metastases to liver and bones. It is unusual for renal cell carcinoma to undergo sarcomatous transformation and to metastasize to the liver before reaching other organs. We speculate that immunosuppressants may have altered malignant cell proliferation, invasion, and the form of metastasis in this case.

Elevation of serum creatine kinase during treatment with antithyroid drugs in patients with hyperthyroidism due to Graves disease. A novel side effect of antithyroid drugs

We describe 4 patients with Graves disease who had abnormal increases of serum creatine kinase (CK) concentrations during treatment with antithyroid medications. Three of the patients experienced myalgia and muscle cramps. All of the patients manifested an increase in serum CK levels 1 to 3 months after the administration of antithyroid drugs. Thyrotropin concentrations and cardiac systolic time indexes during the elevation of serum CK concentrations were not consistent with hypothyroidism. The mechanisms are not obvious, but it is likely that the rapid decrease of thyroid hormones in tissues may temporarily cause hypothyroid states, resulting in alterations in CK concentrations. It is suggested that hasty correction of thyrotoxicosis should be avoided in susceptible patients, unless the thyrotoxic conditions are critical.

Inhibition of peroxisome proliferator signaling pathways by thyroid hormone receptor. Competitive binding to the response element

Peroxisome proliferators (e.g. clofibric acid) and thyroid hormone play an important role in the metabolism of lipids. These effectors display their action through their own nuclear receptors, peroxisome proliferator-activated receptor (PPAR) and thyroid hormone receptor (TR). PPAR and TR are ligand-dependent, DNA binding, trans-acting transcriptional factors belonging to the erbA-related nuclear receptor superfamily. The present study focused on the convergence of the effectors on the peroxisome proliferator response element (PPRE). Transcriptional activation induced by PPAR through a PPRE was significantly suppressed by cotransfection of TR in transient transfection assays. The inhibition, however, was not affected by adding 3,5,3'-triiodo-L-thyronine (T3). Furthermore, the inhibition was not observed in cells cotransfected with retinoic acid receptor or vitamin D3 receptor. The inhibitory action by TR was lost by introducing a mutation in the DNA binding domain of TR, indicating that competition for DNA binding is involved in the molecular basis of this functional interaction. Gel shift assays revealed that TRs, expressed in insect cells, specifically bound to the 32P-labeled PPRE as heterodimers with the retinoid X receptor (RXR). Both PPAR and TR bind to PPRE, although only PPAR mediates transcriptional activation via PPRE. TR.RXR heterodimers are potential competitors with PPAR.RXR for binding to PPREs. It is concluded that PPAR-mediated gene expression is negatively controlled by TR at the level of PPAR binding to PPRE. We report here the novel action of thyroid hormone receptor in controlling gene expression through PPREs.

History of vitamin D treatment of renal osteodystrophy

Vitamin D treatment was tried when renal osteodystrophy was first recognized in the early 20th century, using vitamin D2, D3, or dihydrotachysterol. Large doses of vitamin D2 or D3 (150,000-500,000 IU) were prescribed by monitoring serum calcium, phosphate, and alkaline phosphatase. After the discovery of 1,25-dihydroxycholecalciferol, this compound or 1 alpha-hydroxycholecalciferol was applied to the treatment of renal osteodystrophy. In a preclinical study, especially of 1 alpha-hydroxycholecalciferol, nephritogenoside nephritis was the most responsive condition. These active vitamin D preparations are now widely used in patients with chronic renal failure under hemodialysis. Other active vitamin D compounds, such as hexafluoro-1,25-dihydroxycholecalciferol and 22-oxacalcitriol, are also under investigation.

Acromegaly associated with Chiari-I malformation and polycystic ovary syndrome

We report a 19-year-old female case of acromegaly associated with Chiari-I malformation and polycystic ovary syndrome. She also had syringomyelia and thoracic scoliosis. Although the association of acromegaly and Chiari-I malformation was by chance, exaggerated secretion of growth hormone may have aggravated the scoliosis. The incidence of polycystic ovary in acromegalic patients remains to be elucidated. However, elevation of plasma insulin and insulin-like growth factor, that is usually observed in patients with acromegaly, could stimulate androgen production in the ovaries. The patient was successfully treated with transsphenoidal adenomectomy for pituitary tumor and correction surgery for thoracic scoliosis.

1,25-dihydroxyvitamin D3 and 22-oxacalcitriol prevent the decrease in vitamin D receptor content in the parathyroid glands of uremic rats

Decreased content of the 1,25-dihydroxyvitamin D3 receptor (VDR) in parathyroid glands from patients and animals with chronic renal failure has been implicated in the pathogenesis of secondary hyperparathyroidism. In these studies, we examined the regulation of VDR by 1,25-dihydroxyvitamin D3 (1,25-D3) and 22-oxacalcitriol (OCT) in parathyroid glands of uremic rats. After eight weeks of renal failure, VDR content in parathyroid glands of uremic rats was decreased (400 +/- 42 vs. 729 +/- 47 fmol/mg protein in normal control rats, P < 0.05) and strongly correlated with serum 1,25-D3 levels (r = 0.829, P = 0.0001). Treatment with either 1,25-D3 or OCT prevented the decrease in VDR. We conclude that low serum 1,25-D3 levels, at least in part, account for the decrease in VDR content in parathyroid glands of uremic rats and that treatment with 1,25-D3 or OCT prevents this decrease ameliorating the development of secondary hyperparathyroidism.

Molecular cloning and expression of human caldecrin

Earlier we reported the primary structure of serum calcium-decreasing factor (caldecrin) from rat pancreas, a protein which is considered to be a member of the elastase family. In this report, we describe the isolation of the two homologous cDNA clones encoding caldecrin from human pancreas, the structures of which are identical except for one base and the corresponding amino acid residue. These human caldecrin isoforms are composed of a signal peptide of 16 amino acids, a propeptide of 13 amino acids, and a mature form of 239 amino acids. Both recombinant caldecrins showed the same chymotrypsin-type protease activity and hypocalcemic activity. The hypocalcemic activity of both remained intact even after treatment with PMSF to abolish their protease activity. These results suggest that human caldecrin possesses hypocalcemic activity that has no connection with its protease activity.

In vitro metabolism of the vitamin D analog, 22-oxacalcitriol, using cultured osteosarcoma, hepatoma, and keratinocyte cell lines

Using four cultured cell models representing liver, keratinocyte, and osteoblast, we have demonstrated that the vitamin D analog, 22-oxacalcitriol is degraded into a variety of hydroxylated and side chain truncated metabolites. Four of these metabolic products have been rigorously identified by high pressure liquid chromatography, diode array spectrophotometry, and gas chromatography-mass spectrometry analysis as 24-hydroxylated and 26-hydroxylated derivatives as well as the cleaved molecules, hexanor-1alpha,20-dihydroxyvitamin D3 and hexanor-20-oxo-1alpha-hydroxyvitamin D3. Comparison with chemically synthesized standards has revealed the stereochemistry of the biological products. Although differences exist in the amounts of products formed with the different cell types, it is apparent that 22-oxacalcitriol is subject to metabolism by both vitamin D-inducible and noninducible enzymes. Time course studies suggest that the truncated 20-alcohol is derived from a side chain hydroxylated molecule via a hemiacetal intermediate and the 20-oxo derivative is likely formed from the 20-alcohol. Biological activity measurements of the metabolites identified in our studies are consistent with the view that these are catabolites and that the biological activity of 22-oxacalcitriol is due to the parent compound. These results are also consistent with recent findings of others that the biliary excretory form of 22-oxacalcitriol is a glucuronide ester of the truncated 20-alcohol.

Effects of a synthetic vitamin D analog, ED-71, on bone dynamics and strength in cancellous and cortical bone in prednisolone-treated rats

To determine the action of corticosteroid on bone metabolism and assess the effects of a synthetic vitamin D analog, ED-71, on them, 56 SD rats, 8 weeks of age, were assigned to seven groups of eight animals each. Group 1 was the basal control. Group 2 was the nontreated control. Groups 3-7 were given prednisolone at 30 mg/kg of body weight (BW) twice a week and concomitantly administered ED-71 with respective doses of 0, 0.0125, 0.025, 0.05, and 0.1 micrograms/kg of BW for 12 weeks. In group 3, urinary calcium (U-Ca) and deoxypyridinoline (U-Dpy) were significantly increased compared with group 2. In groups 4-7, U-Ca values were increased but U-Dpy values were dose-dependently decreased. Age-dependent increases in the parameter values of BMD, compressive strength, trabecular bone volume (BV/TV), and trabecular thickness (Tb.Th) of the lumbar body were significantly suppressed in group 3 but dose-dependently increased in groups 4-7, and the values of group 7 exceeded those of group 2. The parameters of bone mineral density (BMD) and the bending strength of the femur in groups 4-7 were larger than the values in group 3 but did not reach the levels of group 2. The trabecular bone formation rate (BFR/BS) of the lumbar body measured by calcein labeling in group 3 was reduced when compared with group 2, but the values were not further decreased in groups 4-7. The perimeter ratios of double labels over single labels (dLS/sLS) greatly decreased by prednisolone, were dose-dependently increased to the level of the normal control by ED-71. Double-labeled perimeters and the dLS/sLS ratios were also increased in the periosteal envelope of the midfemur. These findings clearly demonstrate that prednisolone administration affects the age-related changes in bone metabolism, and ED-71 administration counteracts the effects by increasing intestinal calcium absorption, reducing bone resorption, and enhancing mineralization. The action of ED-71, however, seems to be less potent in the cortical bone.

Molecular cloning and expression of serum calcium-decreasing factor (caldecrin)

We previously reported on the purification of a serum calcium-decreasing factor, referred to as caldecrin, from porcine pancreas, that is thought to be a serine protease (Tomomura, A., Fukushige, T., Noda, T., Noikura, T., and Saheki, T. (1992) FEBS Lett. 301, 277-281). In the present study, we purified caldecrin from rat pancreas and determined its primary structure by cDNA cloning. The predicted caldecrin protein is presumed to be synthesized as a preproenzyme of 268 amino acids with a signal peptide of 16 amino acids and an activation peptide of 13 amino acids, and is, with the exception of a central region, almost identical to the reported rat pancreatic elastase IV sequence. The caldecrin gene is selectively expressed in the pancreas, as judged by Northern blot analysis. After expression in BMT-10 cells, immunoreactive caldecrin was found in the culture supernatant, and it inhibited the parathyroid hormone-stimulated 45Ca release from cultured fetal long bones. Catalytic site mutants were synthesized in a baculovirus system, and recombinant mutants also decreased the serum calcium level of mice. These data implicate caldecrin, a protease closely related to elastase IV, in the regulation of blood calcium levels.

[An autopsy care of hemophagocytic syndrome associated with miliary tuberculosis]

A 56-year-old female with chronic renal failure secondary to diabetic glomerulosclerosis was hospitalized and had a fluminant clinical course with pancytopenia, abnormal liver function tests, and coagulopathy. Bone marrow aspirate findings were typical of reactive hemophagocytosis. The patient died after 21 days of hospitalization and autopsy findings showed disseminated miliary tuberculosis. To our knowledge, only eight cases of miliary tuberculosis with bone marrow hemophagocytosis have previously been described. The presence of reactive hemophagocytosis requires a prompt and thorough search for treatable infections.

Mouse primary osteoblasts express vitamin D3 25-hydroxylase mRNA and convert 1 alpha-hydroxyvitamin D3 into 1 alpha,25-dihydroxyvitamin D3

We examined whether 1 alpha-hydroxyvitamin D3 (1 alpha(OH)D3) is metabolized into 1 alpha,25-dihydroxyvitamin D3 (1 alpha,25(OH)2D3) in bone. Northern blot analysis indicated that the expression of vitamin D3 25-hydroxylase mRNA was highest in the liver, followed by the duodenum, calvaria, lung, kidney, skin and long bone, and lowest in the spleen. Of the bone cell fractions isolated from fetal mouse calvaria by a sequential enzymatic digestion, fraction 3, which consisted of mostly osteoblastic cells, showed the highest expression of vitamin D3 25-hydroxylase mRNA. When either cultured bone cells of fraction 3 or mouse calvaria were incubated with [3H]-1 alpha (OH)D3, a radioactive peak which comigrated at the same position as authentic 1 alpha,25(OH)2D3 was found on an HPLC chromatogram. The radioactive fraction obtained from the conditioned media of fetal mouse calvaria was tentatively identified as 1 alpha,25(OH)2D3 by cochromatography with authentic 1 alpha,25(OH)2D3 on three different HPLC systems and a thermal isomerization analysis. These results indicate that 1 alpha(OH)D3 is hydroxylated at the 25-position in bones, resulting in the local synthesis of 1 alpha,25(OH)2D3 from 1 alpha(OH)D3 in the skeletal tissues.

Response of hepatic proteins to 3,5,3'-tri-iodo-L-thyronine in diabetic rats

In order to study whether peripheral action of thyroid hormones is altered in insulin deficiency and to elucidate the biological consequences of alteration of the cytosolic 3,5,3'-tri-iodo-L-thyronine (T3) binding protein (CTBP), we measured malic enzyme, T3-responsive nuclear n protein, CTBP and nuclear thyroid hormone receptor in the liver and kidney of streptozotocin (STZ)-induced diabetic rats that were treated with or without insulin and/or a receptor-saturating dose of T3. The following results were obtained. 1. Induction of malic enzyme by T3 was apparently diminished in diabetic rats. However, supplementary injection of insulin enabled previously given T3 to take effect in diabetic rats. 2. T3-responsiveness of other hepatic proteins (n protein and CTBP) was not altered by insulin in diabetic rats. 3. The level of n protein was increased by insulin in diabetic rats in vivo and in perfused rat liver, indicating that the hepatic n protein is a novel insulin-responsive protein. T3 and insulin increased the level of n protein non-synergistically in diabetic rat liver. 4. Hepatic nuclear receptor levels were not altered in diabetic rats. 5. Hepatic CTBP levels were decreased in diabetic rats. This was not due to the toxic effect of STZ. Low CTBP level was only partially increased by insulin after 30 days of diabetic period. Renal CTBP levels were not altered in diabetic rats with or without insulin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The binding properties, with blood proteins, and tissue distribution of 22-oxa-1 alpha,25-dihydroxyvitamin D3, a noncalcemic analogue of 1 alpha, 25-dihydroxyvitamin D3, in rats

The binding properties, with blood proteins, and tissue distribution of 22-oxa-1 alpha,25-dihydroxyvitamin (22-oxacalcitriol; OCT), a noncalcemic analogue of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3], in rats were investigated. The binding affinity of OCT to plasma vitamin D binding protein (DBP) is extremely low and OCT mainly circulates in the blood as an intact form nonspecifically bound to lipoproteins especially to chylomicrons and low density lipoprotein (LDL). OCT intravenously injected into normal rats rats rapidly disappeared from the blood, and rapidly appeared in the bile as glucuronides of intact OCT and 1 alpha, 3 beta,20(S)-trihydroxy-9,10-secopregna-5,7,10(19)-triene (23,24,25,26, 27-pentanorOCT; pentanorOCT) as an OCT metabolite. When OCT or 1,25(OH)2D3 was injected into normal rats, significant amounts of OCT and 1,25(OH)2D3 were quickly detected in the thyroid and parathyroid glands, thymus, adrenals, liver, plasma, small intestine, kidneys, and calvaria. The detected amounts of OCT in the parathyroid glands, thymus, adrenals, liver, small intestine, and kidneys were significantly higher than the respective values for 1,25(OH)2D3 2 and/or 10 min after injection, while those of OCT in the plasma and calvaria were significantly lower than those of 1,25(OH)2D3. The in vivo rapid turn-over, nonspecific transportation, and incorporation of detectable amounts into the tissues are typical characteristics of OCT which may account for its specific activities.

A novel synthetic vitamin D analogue, 2 beta-(3-hydroxypropoxy)1 alpha, 25-dihydroxyvitamin D3 (ED-71), increases bone mass by stimulating the bone formation in normal and ovariectomized rats

We performed dosing experiments to evaluate the bone mass increasing action of a novel, synthetic vitamin D derivative, 2 beta-(3-hydroxypropoxy)-1 alpha,25(OH)2D3 (ED-71), in normal and estrogen-deficient rats. The first experiment consisted of 31 Sprague-Dawley rats, 28 weeks of age. The second experiment consisted of 44 animals who were ovariectomized (OVX) or sham operated at the age of 12 weeks. ED-71 was given twice a week for the duration of 12 weeks. At the end of the experiments, serum chemistries were examined and lumbar vertebrae were assessed histomorphometrically. Serum alkaline-phosphatase levels tended to decrease by ED-71 administration in the first experiment and their elevated values after ovariectomy were also depressed by ED-71 in the second experiment. Serum osteocalcin levels, however, increased by the agent. In the first experiment, cancellous bone volume (BV/TV) increased dose dependently. Bone formation rates (BFR/BS) also increased. In the second experiment, BV/TV significantly decreased by ovariectomy and it increased in ED-71-treated groups, but not in 1 alpha-(OH)D3-treated group. BFR/BS increased by ED-71. Activation frequency did not decrease by ED-71 in either experiment. These data clearly demonstrated that ED-71 administration was capable of increasing the bone mass by stimulating bone formation in normal and estrogen-deficient rats.

1 alpha-hydroxyvitamin D3 inhibits type II collagen-induced arthritis in rats

The effects of 1 alpha-hydroxyvitamin D3 and 24,25-dihydroxyvitamin D3 on Type II collagen-induced arthritis in rats, an experimental model of rheumatoid arthritis, were examined. Oral administration of 1 alpha-hydroxyvitamin D3 significantly suppressed the incidence of arthritis and inhibited hind paw swelling. The level of anti-Type II collagen antibodies was decreased in the 1 alpha-hydroxyvitamin D3 treated-group. In contrast, 24,25-dihydroxyvitamin D3, indomethacin, and gold had no effect on either the incidence of arthritis or the antibody levels. These findings demonstrate a beneficial effect of 1 alpha-hydroxyvitamin D3 on Type II collagen-induced arthritis in rats and indicate that it has an antirheumatic effect.

Caldecrin proform requires trypsin activation for the acquisition of serum calcium-decreasing activity

Proform serum calcium-decreasing factor (procaldecrin) was purified from porcine pancreas acetone powder. Procaldecrin showed chymotrypsin activity after trypsin treatment in a time- and dose-dependent manner. Procaldecrin did not possess serum calcium-decreasing activity but acquired serum calcium-decreasing activity as well as protease activity after trypsin treatment. However, PMSF treatment after activation of procaldecrin by trypsin did not affect the serum calcium-decreasing activity, even though protease activity was nullified by treatment with PMSF. These findings suggest that the serum calcium-decreasing activity acquired by procaldecrin requires conformational change caused by trypsin treatment.

Differential catabolism of 22-oxacalcitriol and 1,25-dihydroxyvitamin D3 by normal human peripheral monocytes

22-Oxacalcitriol [1,25-(OH)2-22oxa-D3] mimics the action of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] in a variety of target tissues, including the systemic control of calcitriol metabolism. Similar to 1,25-(OH)2D3, 1,25-(OH)2-22oxa-D3 decreases the rate of 1,25-(OH)2D3 synthesis and accelerates its metabolic clearance rate. We have previously shown that in normal human monocytes, physiological concentrations of 1,25-(OH)2D3 and 1,25-(OH)2-22oxa-D3 determine identical suppression of 1,25-(OH)2D3 synthesis. Moreover, both sterols have a similar potency to induce vitamin D degradation through stimulation of the C24-hydroxylation pathway. In this study, we examined the ability of normal human monocytes to metabolize 1,25-(OH)2-22oxa-D3 and whether the enzymes involved are the same as those that catabolize 1,25-(OH)2D3. Time-course experiments demonstrated no detectable basal catabolic activity. However, exogenous 1,25-(OH)2D3 at physiological concentrations induced 1,25-(OH)2-22oxa-D3 degradation by normal human monocytes. Competition experiments showed that a 10-fold molar excess of unlabeled 1,25-(OH)2D3 inhibited tritiated-1,25-(OH)2-22oxa-D3 catabolism by 85%, whereas a 10-fold excess of unlabeled 1,25-(OH)2-22oxa-D3 reduced tritiated-1,25-(OH)2-22oxa-D3 catabolism by 33%. In contrast, although a 10-fold excess of unlabeled 1,25-(OH)2D3 reduced tritiated 1,25-(OH)2D3 catabolism by 60%, a 1000-fold excess of 1,25-(OH)2-22oxa-D3 was required to reduce tritiated 1,25-(OH)2D3 catabolism to this degree. The apparent Km for 1,25-(OH)2-22oxa-D3 was significantly higher than that of 1,25-(OH)2D3 (2.0 +/- 0.8 0.9 +/- 0.2 nM, respectively; P < 0.001) for the catabolic pathway induced by physiological concentrations of 1,25-(OH)2D3. Moreover, the presence of 0.65 nM 1,25-(OH)2D3 caused an additional increase in the Km for 1,25-(OH)2-22oxa-D3 (3.2 +/- 0.8 nM). These data suggest that 1,25-(OH)2-22oxa-D3 may be less accessible than 1,25-(OH)2D3 to the hydroxylases involved in vitamin D catabolism. The resulting prolonged biological half-life of the analog in certain target tissues may be involved in its selectivity.

22-Oxacalcitriol: dissection of 1,25(OH)2D3 receptor-mediated and Ca2+ entry-stimulating pathways

22-Oxa-1,25-dihydroxyvitamin D3 (oxacalcitriol, or OCT) is a bioactive analogue of 1 alpha,25-dihydroxyvitamin D3 [1,25(OH)2D3] with lower calcemic activity than the parent compound. We investigated the ability of OCT to stimulate 1) genomic pathways mediated by nuclear receptors for 1,25(OH)2D3 versus 2) nongenomic pathways mediated by voltage-sensitive Ca2+ channels in growth phase rat osteosarcoma cells (ROS 17/2.8) and in chick intestine. Effects on nuclear receptor-mediated pathways were evaluated by measuring the ability of OCT to compete with [3H]1,25(OH)2D3 for soluble receptors. We also measured the ability of OCT to increase mRNA encoding osteoblast marker proteins osteopontin (OPN) and osteocalcin (OCN), which are both increased by 1,25(OH)2D3. Effects on Ca2+ entry into osteoblasts were measured using 45Ca2+ influx assays. The rapid stimulation of calcium absorption (transcaltachia) in chick intestine treated with OCT also was measured. We found that OCT bound to the nuclear receptor with lower binding affinity [relative competitive index (RCI) = 48.1 for ROS 17/2.8; RCI = 14.8 for chick intestine] than 1,25(OH)2D3 (RCI = 100). Like 1,25(OH)2D3, OCT increased mRNA levels of OPN and OCN in ROS 17/2.8 cells over a 48-h period. In contrast, OCT had no effect on transmembrane influx of 45Ca2+ across ROS cell membranes, whereas uptake was stimulated within 1 min by 1 nM 1,25(OH)2D3. In transcaltachia assays in perfused duodenum, OCT stimulated absorption with a maximum response at 6.5 nM.(ABSTRACT TRUNCATED AT 250 WORDS)

n-Butyrate enhances induction of thyroid hormone-responsive nuclear protein

Effects of n-butyrate on nuclear thyroid hormone receptors and on thyroid hormone-responsive nuclear protein were investigated by means of a perfusion system in rat liver. Treatment with 5 mM n-butyrate resulted in an increase (150%) in the maximal binding capacity of 3,5,3'-L-triiodothyronine (T3) nuclear receptors without altering the affinity of receptor for T3. However, further perfusion for 4 h decreased the number of the receptors to the control level. n-Butyrate increased the amount of acetylated histone H4. The ability of nuclear T3 receptors to bind to core histones was diminished by acetylation of the core histones. Thyroid hormone-responsive nuclear protein (n protein) was increased by T3. The induction of the n protein by T3 was augmented by n-butyrate. These results suggested that n-butyrate modulates thyroid hormone-responsive gene expression in rat liver via the increased number of nuclear receptors or changes in the chromatin constitution.

The mechanism for the disparate actions of calcitriol and 22-oxacalcitriol in the intestine

22-Oxacalcitriol (OCT) is one of several new analogs of vitamin D that retain many of the therapeutically useful properties of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3], but have much less calcemic activity. In the present study we examined the actions of OCT on intestinal calcium absorption and calbindin D9k mRNA in vitamin D-deficient rats. After ip injection of OCT (1 microgram/kg), calcium absorption increased significantly by 2 h and was maximal at 4 h (2.5-fold above control), but returned to pretreatment levels by 16 h. In contrast, the same dose of 1,25-(OH)2D3 caused a 3-fold increase in calcium absorption, which lasted more than 48 h. The transient effect of OCT on calcium absorption was also observed when the analog was infused at a dose of 1 micrograms/kg.day for 3 days. At the end of the infusion period, calcium absorption was 3-fold higher than that in vehicle-infused controls, but fell to pretreatment levels by 24 h after removing the minipumps. The time courses for induction of calbindin D9k mRNA were similar for OCT and 1,25-(OH)2D3, with no change observed until more than 4 h after injection. However, calbindin mRNA levels returned to pretreatment values more rapidly in the OCT-treated rats. Consistent with these findings, we observed that a 1 microgram/kg dose of [3H] OCT was completely cleared by 4-6 h after injection. This was paralleled by a loss of [3H]OCT associated with the intestinal vitamin D receptor. The rapid clearance of OCT is probably due to its low affinity for the serum vitamin D-binding protein. This low affinity would also be expected to allow greater accessibility to target cells. In support of this, we found that higher amounts of OCT than 1,25-(OH)2D3 were associated with the intestinal vitamin D receptor after the injection of several doses of these tritiated ligands. In summary, our results indicate that the pharmacokinetic properties of OCT are responsible at least in part for its low calcemic activity. Furthermore, comparison of the transient elevation of calcium absorption by OCT with its more prolonged effects on PTH and calbindin D9k indicates that each action of vitamin D compounds has a distinct biological half-life. The short circulating half-life of OCT can exploit these differences to provide a therapeutic advantage in the treatment of vitamin D-responsive diseases.

Induction of cytosolic triiodo-L-thyronine (T3) binding protein (CTBP) by T3 in primary cultured rat hepatocytes

Cytosolic 3, 5, 3'-triiodo-L-thyronine (T3)-binding protein (CTBP) plays an important role in the regulation of intracellular T3 translocation from cytoplasm to the nuclear T3 receptor. We examined whether the CTBP activity could be induced by T3 or not in cultured hepatocytes prepared from thyroidectomized rats. CTBP activity was not detected in primary cultured hepatocytes from thyroidectomized rats. However, the protein was induced by the addition of T3 to the culture medium. The increase in the activity of CTBP was time dependent and the maximal level was obtained by 48 h in the presence of 300 nM T3. CTBP activity was also increased by retinol (35 microM) or by 1,25-(OH)2-vitamin D3 (10 nM). On the other hand, the activity of malic enzyme (ME) was induced by the addition of T3 to the culture medium. The maximal activity of ME was obtained by 48 h in the presence of 300 nM T3. The increase in ME activity was also induced by retinol or 1,25-(OH)2-vitamin D3. These results suggested that not only ME activity but also CTBP activity is induced by T3. Further, retinol and vitamin D3 have similar effects on the induction of CTBP activity and ME activity.

Antitumor effect of 22-oxa-calcitriol, a noncalcemic analogue of calcitriol, in athymic mice implanted with human breast carcinoma and its synergism with tamoxifen

The antitumor effect of 22-oxa-calcitriol (OCT), a newly developed noncalcemic analogue of calcitriol, was examined in vivo in athymic mice implanted with human breast carcinoma with or without estrogen receptor (ER). In ER-positive MCF-7 tumor, the growth of which was dependent on exogenous estrogen, administration p.o. of OCT as well as the antiestrogen tamoxifen five times a week for 4 weeks suppressed tumor growth in a dose-related fashion. The antitumor effect of 1.0 microgram/kg body weight (BW) OCT (mean +/- SEM of tumor weight in 6 mice: 28 +/- 4% of vehicle-treated group) was comparable to that of 2.0 mg/kg BW tamoxifen (25 +/- 6% of control group). In addition, a synergistic antitumor effect of submaximal doses of OCT and tamoxifen was observed in MCF-7 tumor in vivo as well as in ER-positive breast carcinoma cell lines (MCF-7 and ZR-75-1) in vitro. Administration of OCT p.o. three times a week for 4 weeks also suppressed the growth of ER-negative MX-1 tumor in a dose-dependent manner without raising serum calcium concentrations. The antitumor effect of 1.0 microgram/kg BW OCT (mean +/- SEM of tumor weight in 10 mice: 44 +/- 6% of vehicle-treated group) was greater than that of 500 micrograms/kg BW Adriamycin (71 +/- 6% of control group). These results indicate that OCT suppresses the growth of ER-negative as well as ER-positive breast carcinoma in vivo without causing hypercalcemia and that the antitumor effect of OCT can be enhanced by tamoxifen in an ER-positive tumor. It is suggested that OCT may provide a new strategy, either alone or in combination with other anticancer drugs, for systemic adjuvant therapy of breast carcinoma regardless of ER status.