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Y Nishii

Publications and source records attributed to Y Nishii.

At least 37 records · Page 2Linked to original sources
PubMed1995

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.

Amino Acid Sequence↗
PubMed1995

[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.

Female↗
PubMed1995

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.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed1994

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.

Animals↗
PubMed1994

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.

Alkaline Phosphatase↗
PubMed1994

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.

Animals↗
PubMed1994

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)

Animals↗
PubMed1993

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.

Amino Acid Sequence↗
PubMed1993

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.

Animals↗
PubMed1993

Effects of two new vitamin D3 derivatives, 22-oxa-1 alpha-25-dihydroxyvitamin D3 (OCT) and 2 beta-(3-hydroxypropoxy)-1 alpha, 25-dihydroxyvitamin D3 (ED-71), on bone metabolism in organ culture.

We have tested two new vitamin D3 derivatives, 22-oxa-1 alpha, 25-dihydroxyvitamin D3 (OCT) and 2 beta-(3-hydroxypropoxy)-1 alpha, 25-dihydroxyvitamin D3 (ED-71), for their effects on bone metabolism compared with 1 alpha, 25-dihydroxyvitamin D3 (1,25(OH)2D3) in two organ-culture systems. In a previous study (Abe et al. 1987), it was reported that OCT had weak activity in stimulating bone resorption in vitro. In the present study, however, OCT stimulated bone resorption in cultured fetal rat long bones and inhibited collagen synthesis in cultured neonatal mouse calvariae in a dose-dependent manner with significant effects at 10(-10) M and maximal responses at 10(-8) M. Its potency and effectiveness were identical to 1,25(OH)2D3. On the other hand, ED-71, which has been found to prevent bone loss in vivo (Okano et al. 1989b), was less active in vitro. The activity of ED-71 at 10(-8) M on bone resorption was similar to 1,25(OH)2D3, but it did not stimulate resorption at 10(-10) M. Its inhibitory effect on collagen synthesis was weaker than for OCT of 1,25(OH)2D3. The activity of all three compounds on bone resorption was not inhibited by indomethacin or cortisol. 1,25(OH)2D3 and OCT significantly inhibited [3H]-thymidine incorporation into mouse calvariae at 10(-9) M, while ED-71 inhibited [3H]-thymidine incorporation only at 10(-8) M. These results indicate that OCT and 1,25(OH)2D3 have similar effects on bone in organ culture. Pharmacokinetic differences may explain the marked difference in response to those two agents in vivo. ED-71 is less potent, particularly in inhibiting bone formation. Such differences may have importance in the development of vitamin D analogs for clinical use.

Animals↗
PubMed1993

Differential effects of 1,25-(OH)2D3 and 22-oxacalcitriol on phosphate and calcium metabolism.

1,25-dihydroxyvitamin D3 has been used with success in the treatment of secondary hyperparathyroidism associated with chronic renal failure. However, frequently 1,25-(OH)2D3 induces hypercalcemia, especially in those patients ingesting large doses of calcium carbonate, precluding the administration of therapeutic doses of 1,25-(OH)2D3. In addition, control of serum phosphorus is a persistent problem in patients maintained on chronic hemodialysis and 1,25-(OH)2D3 treatment can aggravate the hyperphosphatemia. Thus, ideally an analog of 1,25-(OH)2D3 that can suppress PTH with minor effects on calcium (Ca) and phosphate (PO4) metabolism would be an ideal tool to control secondary hyperparathyroidism. We have shown that 22-oxa-1,25-(OH)2D3 (OCT), an analog of 1,25-(OH)2D3 with little calcemic activity, can suppress PTH mRNA in normal rats and in cultured bovine parathyroid cells with equipotency to 1,25-(OH)2D3. To further characterize the differential effects of 1,25-(OH)2D3 and OCT on Ca and PO4 metabolism we performed several experiments in intact and parathyroidectomized (PTX) rats. In metabolic studies in four groups of normal rats 1,25-(OH)2D3 treatment (8 ng/day) significantly increased the intestinal Ca absorption from 15.2 +/- 2.68% to 30.5 +/- 2.85% (P < 0.01), while the same dose of OCT had no effect. A dose of 200 ng/day of OCT increased intestinal Ca absorption similarly to the 8 ng/day dose of 1,25-(OH)2D3, from 10.6 +/- 2.49% to 24.8 +/- 2.35% (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

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)

Animals↗
PubMed1993

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.

Animals↗
PubMed1993

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.

Binding, Competitive↗
PubMed1993

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.

Animals↗
PubMed1993

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.

Acetylation↗