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K Fujiyama

Publications and source records attributed to K Fujiyama.

At least 37 records · Page 2Linked to original sources
PubMed1998

Inhibitory effect of glucocorticoid for osteoblast apoptosis induced by activated peripheral blood mononuclear cells.

Recent studies suggest a protective effect of glucocorticoid against progression of bone erosion and periarticular osteoporosis in patients with rheumatoid arthritis (RA), although this steroid hormone itself is believed to increase bone loss. To understand the antagonistic effect of glucocorticoid for osteopenic process in RA patients, we examined the effect of dexamethasone on Fas-mediated apoptosis of cultured human osteoblasts induced by either anti-Fas IgM or activated peripheral blood mononuclear cells (PBMC). Human osteoblastic cell line MG63 and primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMC isolated from healthy donors were cultured with or without recombinant interleukin-2 (rIL-2) followed by 12-O-tetradecanoyl-phorbol 13-acetate (PMA) with ionomycin in the presence or absence of dexamethasone. Fas was functionally expressed on MG63 and primary osteoblast-like cells, and treatment of these cells with dexamethasone affected neither Fas expression nor anti-Fas IgM-induced apoptosis. Activated PBMC expressing membrane-type Fas ligand (mFasL) efficiently killed both MG63 and primary osteoblasts-like cells, and the addition of human Fas chimeric protein (hFas-Fc) significantly diminished the cytotoxicity, indicating that interactions between mFasL of activated PBMC and Fas on human osteoblasts induce apoptosis of the latter. Although dexamethasone did not affect apoptosis of MG63 and primary osteoblast-like cells induced by anti-Fas IgM, treatment of activated PBMC with dexamethasone markedly inhibited both mFasL expression and cytotoxicity of these cells against human osteoblasts, suggesting that dexamethasone preferentially acts not on osteoblasts but PBMC. Cultured supernatants from activated PBMC induced apoptosis of human osteoblasts and the addition of hFas-Fc also inhibited the cytotoxicity of the supernatants. In addition, soluble form FasL (sFasL) was detected in the supernatants of activated PBMC. Furthermore, both the cytotoxicity and sFasL concentration of cultured supernatants of activated PBMC incubated with dexamethasone was significantly lower than that in the absence of dexamethasone. Our data suggest that glucocorticoid suppresses the apoptotic process of osteoblasts by inhibiting the expression of both mFasL and sFasL derived from activated PBMC, mediating a protective effect against periarticular bone loss and bone erosion in inflammatory arthritis such as RA.

Apoptosis↗
PubMed1998

[Bone changes in thyrotoxicosis].

Thyroid hormone (T3) is essential for normal bone growth and bone metabolism. T3 stimulates bone formation directly through T3 receptors in osteoblasts. T3 also stimulates bone resorption by osteoclasts probably secondary through osteoblasts. In thyrotoxicosis accelerated bone formation and resorption resulted in high turn-over bone loss. Bone metabolic markers elevate reflecting thyrotoxic state. Normalizing thyroid hormone level at least partially restore bone mineral content. In patients under thyroid hormone replacement therapy or TSH suppression therapy TSH and free thyroid hormones should be monitored to prevent unnecessary bone loss. Especially in postmenopausal women with thyrotoxicosis or thyroid hormone therapy the assessment of bone mineral content is required.

Bone Resorption↗
PubMed1997

Fas and Fas ligand interaction is necessary for human osteoblast apoptosis.

We investigated the cellular and humoral interactions between peripheral blood mononuclear cells (PBMCs) and human osteoblasts, leading to apoptosis of osteoblasts. Human osteoblastic cell line MG63 and human primary osteoblast-like cells obtained from biopsy specimens were used in this study. PBMCs were isolated from healthy donors and cultured with or without stimulation by recombinant interleukin-2 followed by 12-o-tetradecanoylphorbol 13-acetate with ionomycin. Fas was functionally expressed on MG63 and primary osteoblast-like cells. Activated PBMCs expressed Fas ligand (FasL) strongly on their surface and killed MG63 and primary osteoblast-like cells. Cultured supernatants of activated PBMCs also induced apoptotic cell death of MG63 and primary osteoblast-like cells. In contrast, both unstimulated PBMCs and cultured supernatants of unstimulated PBMCs did not induce apoptosis of these cells. Furthermore, the cytotoxic effect and induction of apoptosis against MG63 and primary osteoblast-like cells by activated PBMCs and cultured supernatants were inhibited significantly by human Fas chimeric protein. Our data showed that human osteoblasts expressed Fas fuctionally and both membrane-type and soluble form FasL from activated PBMCs induced apoptosis of these cells, providing the one possible mechanism of bone loss in inflammatory diseases such as rheumatoid arthritis.

Antigens, Surface↗
PubMed1995

High gene expression in Escherichia coli of recombinant alginate lyase as a fused protein with beta-galactosidase alpha-peptide.

Escherichia coli LE392 (pAL28) was previously isolated as a positive clone harboring the alginate lyase gene (aly) from an alginate-degrading strain, Pseudomonas sp. OS-ALG-9. The plasmid pAL205, one of the constructs obtained after successive subcloning of pAL28, gave the highest expression of aly in E. coli cells. A 8-fold increase in the alginate lyase (Aly) activity in E. coli JM109 (pAL205) was induced with isopropyl-beta-D-thiogalactoside, which was 210 times higher than that in E. coli LE392 (pAL28). The highly significant increase in the expression of the Aly enzyme with pAL205 was investigated through the nucleotide sequence around the 5' region of aly as well as the N-terminal sequence of the purified enzyme. It was found that the Aly expressed in E. coli (pAL205) was a fused protein containing 7 residues from the N-terminus of beta-galactosidase alpha-peptide and the mature protein found in the Pseudomonas sp. except for three residues in the N-terminal.

Alginates↗
PubMed1995

Purification and characterization of the recombinant alginate lyase from Pseudomonas sp. leaked by Escherichia coli upon addition of glycine.

The plasmid pAL205 encodes an alginate lyase gene of Pseudomonas sp. OS-ALG-9, fused in frame to the beta-galactosidase alpha-peptide gene. The alginate lyase (Aly) expressed in Escherichia coli (pAL205) was significantly secreted into the medium by the addition of glycine. The extracellular enzyme isolated from the culture of E. coli JM109 (pAL205) was purified over 15,000-fold by successive chromatography and subjected to amino acid sequence analysis. The sequence determined was identical to that of the intracellular protein. Since the activity and molecular size of the extracellular Aly is identical to the intracellular protein and to the Aly isolated from Pseudomonas, the glycine does not affect or modify the Aly during its leakage into the medium.

Alginates↗
PubMed1995

Effects of Helicobacter pylori infection on gastric mucosal defense factors in Japanese monkeys.

The pathogenic role played by Helicobacter pylori in gastric mucosal defense was investigated in Japanese monkeys infected with H. pylori. Serum gastrin levels and ammonia concentrations in gastric juice were compared in H. pylori-infected (n = 6) and control (n = 7) groups. The gastritis score, the intracellular content of periodic acid-Schiff (PAS)-positive substance and hexosamine, and the bromodeoxyuridine (BrdU) labeling index in the gastric mucosa were compared in the two groups in the antrum and the corpus. The ammonia concentration in the gastric juice was significantly higher in the infected group (P < 0.01). The gastritis scores were significantly higher in the antrum and corpus in the infected group (P < 0.01, and P < 0.05, respectively). The content of PAS-positive substance and hexosamine was significantly decreased in the antrum of the infected group compared with that in the controls (P < 0.01, and P < 0.05, respectively), but there was no significant difference between the two groups in the corpus. The BrdU labeling indices were significantly higher in the antrum and corpus of the infected group (P < 0.01, and P < 0.01, respectively). Colonization by H. pylori injures the gastric mucosa by depressing the gastric mucosal defense factors, and, consequently, the cell kinetics are accelerated.

Ammonia↗
PubMed1995

Effects of ethanol on the pancreas of disulfiram-treated rats.

To study the effects of ethanol on disulfiram-treated rats, we administered ethanol orally at a does of 2000 mg/kg, twice daily for 5 days. The administration of ethanol or disulfiram alone produced no recognizable changes in pancreatic acinar cells. Ethanol administration, in disulfiram-treated rats resulted in a decrease in the content of zymogen granules in acinar cells, and the appearance of intraplasmic vacuolization. Electron microscopically, these vacuoles appeared on the basal side of nuclei. In addition, similar vacuoles appeared in liver cells, and these vacuolizations seemed to show lipid inclusions. However, ethanol administration to disulfiram-treated rats did not cause inflammatory changes or edema in the pancreas. A comparison of blood ethanol levels in rats receiving ethanol alone and disulfiram plus ethanol showed no significant difference, but acetaldehyde levels in rats receiving ethanol plus disulfiram rats were significantly higher than those in rats receiving ethanol alone. These findings suggested that acetaldehyde caused a decrease of zymogen granules and the presence of lipid inclusions in pancreatic acinar cells.

Acetaldehyde↗
PubMed1995

Suppressive doses of thyroxine do not accelerate age-related bone loss in late postmenopausal women.

To examine whether suppressive doses of thyroxine have any adverse effects on bone, we evaluated various bone metabolic markers (lectin-precipitated alkaline phosphatase, osteocalcin, carboxyl-terminal region of type I collagen propeptide, tartrate-resistant alkaline phosphatase, and urinary excretion of hydroxyproline and pyridinium crosslinks), incidence of vertebral deformity, total body and regional (lumbar spine and radius) bone mineral densities (BMDs), and rates of bone loss in 24 late postmenopausal (more than 5 years after menopause) women who were treated with levothyroxine (L-T4) after total thyroidectomy for differentiated carcinoma. Depending on the clinical records, including serum TSH levels measured by immunoradiometric assay, these patients were divided into two groups. One group of patients was given suppressive doses of L-T4 (TSH < 0.1 mU/L, n = 12) and the other group was given nonsuppressive doses of L-T4 (TSH > 0.1 mU/L, n = 12). There was no difference in bone metabolic markers and incidence of vertebral deformity between the groups. In patients with TSH suppression, Z-scores of BMDs calculated from age-matched healthy women (n = 179, aged 55 to 80) were nearly in the zero range of values (0.077 at total body, 0.228 at lumbar spine, and -0.117 at trabecular region of lumbar spine). The rate of bone loss in TSH-suppressed patients (-0.849 +/- 0.605%/year) was not significantly different from that of nonsuppressed patients (-0.669 +/- 0.659). These prospective and cross-sectional data suggest that long-term levothyroxine therapy using suppressive doses has no significant adverse effects on bone.

Aged↗
PubMed1995

Attenuation of postmenopausal high turnover bone loss in patients with hypoparathyroidism.

To elucidate the role of PTH in postmenopausal bone loss, we studied 33 postmenopausal patients who received total thyroidectomy due to thyroid carcinoma. Among these patients, 13 were patients with hypoparathyroid function (HPf), and 20 retained normal parathyroid function (NPf) after thyroidectomy. Bone mineral density (BMD), the rate of BMD loss, and incidence of spinal deformity as well as varying bone metabolic markers were analyzed in all patients. The age-matched BMD was clearly higher, and the incidence of spinal deformity was significantly lower in HPf than in NPf. The rate of BMD loss in HPf was significantly lower than in NPf during the early postmenopausal period (within 5 yr after menopause; mean +/- SD, -0.567 +/- 3.05% vs. -2.49 +/- 1.86%/yr, P < 0.05). In contrast, the rates were similar between the two groups during the late postmenopausal period (> 5 yr after menopause). Bone metabolic markers indicated that an accelerated bone turnover occurred during the early postmenopausal period in NPf, but not in HPf. These results suggest that the hypoparathyroid condition provides protection against age-related bone loss. This is due in part to attenuation of the high turnover bone loss that occurs early in menopause.

Adult↗
PubMed1995

[Serum pepsinogen response to therapy for Helicobacter pylori associated gastro-duodenal disease].

We investigated the effect of H. pylori therapy on serum concentrations of pepsinogens on 87 patients of gastro-duodenal disease. In addition, we intended to see whether serum pepsinogen can serve as markers of response to H. pylori eradication. In 48 successfully eradicated cases, there was a significant decrease in gastritis score, and was a significant fall in serum pepsinogen II (PG II) level, and was a significant increase in pepsinogen I/II ratio (PG I/II ratio). In contrast, no change in gastritis score, PG II, and PG I/II ratio were observed in 39 unsuccessfully eradicated patients. No change in serum pepsinogen I (PG I) level was observed in both groups. In provisional successfully eradicated cases in PG II of decrease greater than 30% in after treatment, there was a sensitivity of 83.3% and a specificity of 89.7%. For the PG I/II ratio of increased greater than 30% in after treatment, the sensitivity was 95.8%, and the specificity was 94.9%. These findings suggest that PG II, PG I/II ratio can be useful for clinical evaluation of eradication therapy.

Adolescent↗
PubMed1995

Influence of Helicobacter pylori infection and the effects of its eradication on gastric emptying in non-ulcerative dyspepsia.

AIM: The aim of the present study was to clarify the effects of Helicobacter pylori infection and its eradication on gastric emptying. SUBJECTS AND METHODS: Out of a total of 52 patients with non-ulcerative dyspepsia, 34 H.pylori-positive patients were enrolled. Antimicrobial drugs for the eradication of H. pylori were administered to 19 out of the 34 H. pylori-positive patients. Gastric emptying was evaluated according to the acetaminophen method. Inflammatory changes and intracellular periodic acid-Schiff-positive substances in the antral mucosa were examined in biopsy specimens. RESULTS: Although gastric emptying was significantly prolonged in the patients with non-ulcerative dyspepsia compared with the control group (P < 0.01), there was no difference in gastric emptying between H. pylori-positive and -negative patients, with all patients showing significantly less gastric emptying than the control group. The H. pylori eradication rate was 58% (11 out of 19) and gastric emptying improved significantly in seven patients whose infection was eradicated and whose dyspeptic symptoms disappeared. The ammonia concentration in gastric juice, inflammatory changes in the gastric mucosa and the index of periodic acid-Schiff-positive substances improved significantly when H. pylori was successfully eradicated compared with patients in whom eradication was unsuccessful. As gut hormones may affect gastroduodenal motility associated with H. pylori infection, we also studied the levels of serum gastrin and cholecystokinin. In the patients whose infection was eradicated, serum gastrin decreased significantly, but the cholecystokinin level did not change significantly, although there was a non-significant trend for cholecystokinin to increase. CONCLUSIONS: These results suggest that delayed gastric emptying is partly associated with H. pylori infection and that the infection may contribute to the development of non-ulcerative dyspepsia.

Adult↗
PubMed1994

Inhibitory effect of fatty acids on glucose and insulin uptake in the perfused rat hindquarter.

To elucidate the effects of fatty acids on the uptake of glucose and insulin in the muscle, the effects of oleic and palmitic acids on the uptake of glucose and insulin were investigated in perfused hind-quarters of rats. In the absence of insulin, glucose uptake in the hindquarter was slightly, but not significantly, decreased by the addition of oleic and palmitic acids. In the presence of 100 or 500 microU/ml insulin, glucose uptake in the hindquarter (243 +/- 58 or 282 +/- 65 mumol/30 min) was significantly decreased by the addition of 1000 microM oleic acid and 500 microM palmitic acid (175 +/- 50 or 207 +/- 47 mumol/30 min). The decrease in insulin uptake rate, although not significant at 500 microU/ml insulin, is of similar magnitude to the decrease in glucose uptake. In the presence of 1000 microU/ml insulin, glucose and insulin uptake was not significantly altered by the addition of fatty acids. These results indicate that fatty acids directly inhibit the muscular glucose uptake via the decrease in muscular insulin uptake at a physiological concentration of insulin.

Adenosine Triphosphate↗
PubMed1994

The nylon oligomer biodegradation system of Flavobacterium and Pseudomonas.

This review article is a compendium of the available information on the degradation of a man-made compound, 6-aminohexanoate-oligomer, in Flavobacterium and Pseudomonas strains, and discusses the molecular basis for adaptation of microorganisms toward these xenobiotic compounds. Three plasmid-encoded enzymes, 6-aminohexanoate-cyclic-dimer hydrolase (EI), 6-aminohexanoate-dimer hydrolase (EII), and endo-type 6-aminohexanoate-oligomer hydrolase (EIII) are responsible for the degradation of the oligomers. Two repeated sequences, designated RS-I and RS-II, are found on plasmid pOAD2, which is involved in 6-aminohexanoate degradation in Flavobacterium. RS-I appears 5 times on the pOAD2, and all copies have the same sequences as insertion sequence IS6100. RS-II appears twice on the plasmid. RS-IIA contains the gene encoding EII, while RS-IIB contains the gene for the analogous EII' protein. Both EII and EII' are polypeptides of 392 amino acids, which differ by 46 amino acid residues. The specific activity of the EII enzyme is 200-fold higher than that of EII'. Construction of various hybrid genes demonstrated that only the combination of two amino acid residues in the EII' enzyme can enhance the activity of the EII' to the same level as that of EII enzyme.

Amino Acid Sequence↗
PubMed1994

Acquired nephrogenic diabetes insipidus secondary to distal renal tubular acidosis and nephrocalcinosis associated with Sjögren's syndrome.

A 52-year-old woman was referred to our hospital because of 16-year history of polyuria and polydipsia. Hyposthenuria, hyperchloremic metabolic acidosis and the inabilities to acidify the urine after acid-loading test and to concentrate the urine in responses to water-deprivation and antidiuretic hormone administration allowed us to diagnose renal tubular acidosis and nephrogenic diabetes insipidus. Radiographic examinations revealed bilateral nephrocalcinosis. The patient was also found to have clinical and laboratory findings characteristic for Sjögren's syndrome. Thus the longstanding, poorly monitored distal renal tubular acidosis associated with Sjögren's syndrome was considered to result in very rare renal complications-nephrocalcinosis and nephrogenic diabetes insipidus. In patients with renal tubular acidosis and/or nephrogenic diabetes insipidus of unknown etiology, therefore, Sjögren's syndrome should be considered as one of primary disorders.

Acidosis, Renal Tubular↗
PubMed1994

Locked-in syndrome and abnormal orientation of the right vertebral artery in a young man.

A 35-year-old man developed a cerebral infarction and experienced transient ischemic attacks originating from the vertebrobasilar artery, as well as locked-in syndrome. He recovered with minimal neurological deficit. On cerebral angiography, the orientation of the right vertebral artery was markedly abnormal as it entered the foramina of the transverse process at the level of the third cervical vertebra. We concluded that the abnormal orientation of the vertebral artery caused the thrombosis and that the transient ischemic attacks, locked-in syndrome and cerebral infarction were brought about by thromboemboli originating in this artery.

Adult↗
PubMed1994

Combination therapy with clarithromycin and sofalcone for eradication of Helicobacter pylori.

OBJECTIVE: To clarify the efficacy of combination therapy with clarithromycin and sofalcone for eradication of Helicobacter pylori. DESIGNS: We studied 42 patients with H. pylori-positive gastroduodenal diseases, who were divided into two groups according to treatment period. Group 1 comprised 27 patients (seven with gastric ulcers, 14 with duodenal ulcers and six with gastritis) treated with a combination of clarithromycin (200 mg, three times a day) + sofalcone (100 mg, three times a day) for 3 weeks. Group 2 comprised 15 patients with chronic active gastritis treated with the same doses of clarithromycin + sofalcone but for only 2 weeks (group 2). The H. pylori status of all patients was assessed by culture, rapid urease test and histological examination at the end of treatment and 4 weeks after the end of treatment. The gastritis score, the index of intracellular periodic acid-Schiff-positive substance in the antral mucosa and the ammonia concentration in gastric secretions were also estimated before and after treatment. RESULTS: In group 1, with over half the patients excluded from the follow-up, H. pylori was eradicated in nine out of 13 patients (69.2%) compared with six out of the complete group of 15 (40.0%) patients in group 2, without serious side effects. In these patients, significant improvements were seen in the gastritis score (P < 0.025), the index of periodic acid-Schiff-positive substances in the antral mucosa (P < 0.025) and the ammonia concentration in gastric secretions (P < 0.02) after treatment. CONCLUSION: These results suggest that modification of the treatment regimen is needed, with higher doses of clarithromycin and combination therapy with proton-pump inhibition.

Ammonia↗