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A Okuyama

Publications and source records attributed to A Okuyama.

At least 19 recordsLinked to original sources
PubMed1998

Molecular cloning of a murine homologue of membrane cofactor protein (CD46): preferential expression in testicular germ cells.

Human membrane cofactor protein (MCP, CD46) has been suggested, although no convincing evidence has been proposed, to be a fertilization-associated protein, in addition to its primary functions as a complement regulator and a measles virus receptor. We have cloned a cDNA encoding the murine homologue of MCP. This cDNA showed 45% identity in deduced protein sequence and 62% identity in nucleotide sequence with human MCP. Its ectodomains were four short consensus repeats and a serine/threonine-rich domain, and it appeared to be a type 1 membrane protein with a 23-amino acid transmembrane domain and a short cytoplasmic tail. The protein expressed on Chinese hamster ovary cell transfectants was 47 kDa on SDS/PAGE immunoblotting, approximately 6 kDa larger than the murine testis MCP. It served as a cofactor for factor I-mediated inactivation of the complement protein C3b in a homologous system and, to a lesser extent, in a human system. Strikingly, the major message of murine MCP was 1.5 kb and was expressed predominantly in the testis. It was not detected in mice defective in spermatogenesis or with immature germ cells (until 23 days old). Thus, murine MCP may be a sperm-dominant protein the message of which is expressed selectively in spermatids during germ-cell differentiation.

Amino Acid Sequence↗
PubMed1998

Expression of Tamm-Horsfall protein in stone-forming rat models.

OBJECTIVES: To examine the expression of Tamm-Horsfall protein (THP) and calcium oxalate deposition in three rat models to clarify whether THP plays an active role in crystal formation or whether crystals induce the secretion of this protein. MATERIALS AND METHODS: A stone-forming rat model (model 1) with marked tubular dilatation in an entire kidney was produced by rendering Wistar rats (aged 8 weeks) hyperoxaluric and hypercalciuric, through compulsorily feeding with 0.12 mL of 5% ethylene glycol (in two doses daily) and 0.5 microgram of vitamin D3 every other day. Two other rat models were also produced. Model 2 comprised stone-forming rats with minimal tubular dilatation, achieved by giving rats the same dose of ethylene glycol once daily, and model 3 comprised stone-free rats with marked tubular dilatation achieved by unilateral ureteric ligation. The rats' kidneys were resected after 4 weeks and all resected kidneys immunohistochemically stained with an antibody to THP. Simultaneously, the location of calcium oxalate (CaOx) crystals was established with von Kossa staining. The relation between crystals and the secretion of THP was also assessed in vitro. Cultured renal epithelial cells (NRK-52E) were stained with an antibody to THP after they had been cultured for 72 h in a medium containing CaOx crystals. RESULTS: In model-1 kidneys with both tubular dilatation and many crystals, there was local and intense expression of THP in many renal tubules. CaOx crystals and the intense expression of THP tended to occur in the same renal tubules. In model 2 kidneys with little tubular dilatation, only a few renal tubules expressed THP strongly and the location of the crystals rarely coincided with that of THP expression. In model 3 kidneys with marked tubular dilatation but no crystals, THP was expressed strongly in many renal tubules. The expression of THP in cultured NRK-52E cells was not stimulated by CaOx crystals. CONCLUSIONS: The results from the in vivo models suggest that THP did not initiate crystal formation and the strong expression of THP was induced not by crystals but by renal tubular damage caused by tubular dilatation. From the close association of THP and crystals in model 1 kidneys, this protein might play a secondary role as an adhesive, promoting stone formation.

Adjuvants, Immunologic↗
PubMed1998

Expression of selenoprotein-P messenger ribonucleic acid in the rat testis.

It has been suggested that a plasma protein, selenoprotein P, functions as an antioxidant and that its mRNA is expressed ubiquitously, including in the testis. To determine its physiological function, we have investigated the expression of selenoprotein-P mRNA in the rat testis. Northern blot analysis showed that selenoprotein P was exclusively expressed in the Leydig cell fraction. In situ hybridization experiments further supported this observation. Testes of rats administered ethylene dimethane sulfonate (EDS) were also examined by Northern blot analysis. Selective degeneration of Leydig cells by EDS treatment resulted in disappearance of selenoprotein-P mRNA from the testis. Furthermore, upon recovery, in association with regenerative differentiation of Leydig cells, reappearance of the selenoprotein-P mRNA was observed. These results indicated that selenoprotein-P mRNA was predominantly expressed in the interstitial Leydig cells.

Animals↗
PubMed1998

Investigation of the possible role of sialic acid in calcium oxalate urolithiasis.

OBJECTIVE: It is considered that sialic acid in urine comprises two different types of sialic acid, that is, the free sialic acid and the bound one which exists as a basic component of urinary macromolecules. The present studies were performed to clarify the role of sialic acid in urine and compare the excretion and concentrations of sialic acid in urine between calcium oxalate (CaOx) stone formers and healthy subjects. METHODS: First, we prepared the crystal surface binding substances from whole human urine. The crystal surface binding substances were digested with sialidase and both the inhibitory activity on CaOx crystal growth and concentrations of sialic acid before and after sialidase digestion were measured. The inhibitory activity of free sialic acid in ultrafiltered urine was also measured. The excretion and concentration of sialic acid in urine from patients with CaOx urolithiasis and healthy controls were determined and compared. RESULTS: The inhibitory activity of crystal surface binding substances on CaOx crystal growth did not show any significant difference before and after sialidase digestion. The free sialic acid had also no effect on CaOx crystal growth. There was no statistically significant difference between CaOx stone formers and healthy controls on the excretion and concentration of sialic acid in urine. The free:bound sialic acid ratio in urine was considered 1:0.97 and 1:1.33 for healthy controls and CaOx stone formers respectively (p = NS). CONCLUSIONS: It is suggested that neither the free sialic acid nor the bound one in urine has a significant inhibitory effect on CaOx crystal growth.

Calcium Oxalate↗
PubMed1997

MAP4 is the in vivo substrate for CDC2 kinase in HeLa cells: identification of an M-phase specific and a cell cycle-independent phosphorylation site in MAP4.

We reported previously that cdc2 kinase decreased the microtubule-stabilizing ability of a major HeLa cell microtubule-associated protein, MAP4, by phosphorylation in vitro [Ookata, K., et al. (1995) J. Cell Biol. 128, 849-862]. An important question raised by this study is whether MAP4 is indeed phosphorylated by cdc2 kinase at mitosis in vivo. We present here evidence that cdc2 kinase is the major M-phase MAP4 kinase, and, further, we identify two phosphorylation sites within the proline-rich domain of MAP4. Metabolic 32P labeling showed the increased phosphorylation of MAP4 at mitosis. A specific inhibitor of cdc2 kinase, butyrolactone I, inhibited phosphorylation of MAP4 both in mitotic HeLa cells and in the mitotic HeLa cell extract. The phosphopeptide map analysis revealed the high similarity of in vivo labeled mitotic MAP4 to that phosphorylated by cdc2 kinase in vitro. Ser-696 and Ser-787, both of which lie within SPXK consensus sequences for cdc2 kinase, were identified as phosphorylation sites in the proline-rich region of MAP4 in vivo and in vitro. Immunoblotting with antibodies that recognize the phosphorylation state of Ser-696 or Ser-787 showed that Ser-787 in the SPSK sequence was specifically phosphorylated at mitosis while Ser-696 in the SPEK sequence was phosphorylated both at mitosis and in interphase. These results suggest that cdc2 kinase directly regulates microtubule dynamics at mitosis through phosphorylation of MAP4 at a number of sites, including Ser-787.

4-Butyrolactone↗
PubMed1997

Incidence of prostatic intra-epithelial neoplasia in Osaka, Japan.

High-grade prostatic intra-epithelial neoplasia (HGPIN) is the most likely precancerous lesion for prostatic carcinoma. A high incidence of its association with cancer has been reported in Western countries. On the other hand, information regarding its incidence is limited in Japan, where the mortality due to prostate cancer is much lower. We reviewed 53 clinical stage T2 or T3 prostatic cancers of Japanese patients living in Osaka, Japan (mean age, 67.2 years). These cases were subdivided into a pre-operatively non-castrated group (34 cases) and a medically or surgically castrated group (19 cases). HGPIN was found in 27 cases. The incidence of HGPIN was significantly lower in the castrated group (21.0%) compared with the non-castrated group (67.6%). In the non-castrated group, patient age, pathological stage, Gleason score, tumor size and serum prostate-specific antigen showed no significant correlation with HGPIN. Advanced pathological stage and tumor size tended to decrease the incidence of HGPIN, although this was not statistically significant. When the study group was limited to stage T2 tumors of the non-castrated group, the incidence of HGPIN was 81.0%. HGPIN in Japan may also be clinically and etiologically significant as a precursor of clinical cancer.

Aged↗
PubMed1997

Mapping of eight testis-specific genes to mouse chromosomes.

We previously identified eight testis-specific genes using antibodies raised against testicular germ cells. They are expressed during spermatogenesis and are presumed to be involved in testicular germ cell differentiation and sperm formation. We have mapped the genomic loci for these testis-specific genes using restriction fragment length variants in interspecific backcross mice. The calmegin gene (Clgn) was mapped to Chr 8. The synaptonemal complex protein gene 1 (Sycp1) probe hybridized with two sequences on different chromosomes; Sycp1-rs2 was mapped to Chr 3, whereas Sycp1-rs3 was mapped to Chr 7. The relaxin-like factor gene (Rlnl) was mapped to Chr 8, and collapsin response mediator protein 1 (Crmp1) was mapped to Chr 5. Three novel genes encoding testis-specific proteins A2 (Tsga2), A8 (Tsga8), and A12 (Tsga12) were mapped to chromosomes 3, X, and 10, respectively.

Animals↗
PubMed1997

Inhibition of osteoblastic cell differentiation by conditioned medium derived from the human prostatic cancer cell line PC-3 in vitro.

Human prostatic carcinoma frequently metastasizes to bone tissue and activates bone metabolism, especially bone formation, at the site of metastasis. It has been reported that an extract of prostatic carcinoma and conditioned medium (CM) of a human prostatic carcinoma cell line, PC-3, established from a bone metastastic lesion, stimulate osteoblastic cell proliferation. However, there is little information about the effect of PC-3 CM on the differentiation of osteoblastic cells. In this study, we investigated the effect of PC-3 CM on the differentiation of two types of osteoblastic cells, primary fetal rat calvaria (RC) cells containing many undifferentiated osteoprogenitor cells, and ROS 17/2.8, a well-differentiated rat osteosarcoma cell line. PC-3 CM inhibited bone nodule formation and the activity of alkaline phosphatase (ALPase), an osteoblastic marker enzyme, on days 7, 14, and 21 (RC cells) or 3, 6, and 9 (ROS 17/2.8 cells) in a dose-dependent manner (5-30% CM). However, the CM did not affect cell proliferation or cell viability. PC-3 CM was found to markedly block the gene expression of ALPase and osteocalcin (OCN) mRNAs but had no effect on the mRNA expression of osteopontin (OPN), the latter two being noncollagenous proteins related to bone matrix mineralization. These findings suggest that PC-3 CM contains a factor that inhibits osteoblastic cell differentiation and that this factor may be involved in the process of bone metastasis from prostatic carcinoma.

Alkaline Phosphatase↗
PubMed1997

Loss of imprinting of the insulin-like growth factor II gene in renal cell carcinoma.

Loss of imprinting (LOI) has been implicated in the pathogenesis of embryonal malignancies as well as adult cancers. Insulin-like growth factor II (IGF2) gene is an imprinted gene, normally transcribed only from the paternal allele. We investigated allele-specific expression of the IGF2 gene in 22 cases of renal cell carcinoma (RCC), a common adult-onset renal tumor. Sixteen cases (72%) were informative for IGF2 gene expression, and 9 (56%) of these cases showed biallelic expression of the IGF2 gene. Additionally, in four cases with biallelic expression from which uninvolved kidney tissue was available, LOI of the IGF2 gene was also demonstrated in the normal tissue. All cases with LOI of IGF2 were low-grade and low-stage tumors. LOI of the IGF2 gene in RCC was not associated with overexpression of IGF2 mRNA, whereas IGF2 overexpression was frequently observed in high-stage tumors. These results suggest that LOI of IGF2 predisposes to low-grade and low-stage tumors, whereas IGF2 overexpression may have a role in RCC tumor progression.

Adult↗
PubMed1997

Malignant lymphoma of the kidney.

BACKGROUND: Primary renal lymphoma (PRL) is a rare disease, making information including etiologic factors for PRL extremely limited. METHODS: Clinical and pathologic findings of PRL in Japan are presented and compared with those from Western countries. The presence of Epstein-Barr virus (EBV) genomes in the tumor was also evaluated. Eight cases of PRL were collected from a review of the "Annual of the Pathological Autopsy Cases in Japan (1976-1992)". These cases fulfilled the following criteria: (1) presence of renal mass without extrarenal lymphomatous involvement at admission and (2) absence of a leukemic blood picture. For histologic and immunohistochemical studies, 10% formalin-fixed and paraffin-embedded histologic specimens were used. Presence of Epstein-Barr virus (EBV) genome was examined by polymerase chain reaction (PCR) and in situ hybridization (ISH). RESULTS: There were five males and three females; age at admission ranged from 15 to 79 years (median 57 yr). Abdominal and/or flank pain were the most common presenting symptoms. No particular past history was present in any of the patients. Histologically, tumor cells in all cases showed a diffuse pattern of proliferation: large cell type in six cases, mixed cell type and small lymphocytic type in 1 each. Immunohistochemistry revealed B-cell nature of lymphoma cells in all cases. Neither PCR nor ISH showed the presence of EBV genome in any cases. CONCLUSIONS: PRL is non-Hodgkin's lymphoma of predominantly large cell type with a B-cell immunophenotype. EBV etiology is unlikely in PRL.

Adolescent↗
PubMed1997

Effect of pre-induction of heat shock proteins on indomethacin-induced small-intestinal lesion in rats.

Systemic hyperthermia induces the synthesis of heat shock proteins (HSPs) in several organs. However, the mechanism of induction and the functions of HSPs in the small-intestinal mucosa have not been established. We examined the expression of HSPs in the small-intestinal mucosa after systemic hyperthermia, and evaluated the cytoprotective function of pre-induced HSPs on experimentally induced mucosal damage. HSP expression was investigated by Western blot and densitometric analysis before and after hyperthermia (42.5 degrees C; 20 min). Expression of a 72-kDa heat shock protein (HSP72) and a 73-kDa heat shock protein (HSP73), both of which are endogenous cytoprotectants in vitro significantly increased, peaking 6-9 h after hyperthermia, without any pathologic alterations, whereas the expression of a 60-kDa heat shock protein (HSP60) did not increase. To investigate the influence of pre-induction of HSPs on small-intestinal damage, rats received indomethacin (10 mg/kg; orally) with or without pre-treatment with hyperthermia. Small-intestinal damage caused by indomethacin was not influenced by pre-induction of HSP72 and HSP73. We demonstrated that systemic hyperthermia induced HSP72 and HSP73, although pre-induction of these proteins did not have a cytoprotective function in the small-intestinal damage caused by indomethacin.

Animals↗
PubMed1997

Characterization of protein components of human urinary crystal surface binding substance.

We previously extracted crystal surface binding substance (CSBS) from human urine and showed that it appeared to constitute a substantial proportion of urinary macromolecular inhibitors of calcium oxalate crystallization. CSBS was isolated from human urine and fractionated by three consecutive chromatography procedures in order to characterize protein inhibitors of calcium oxalate crystallization. Sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and NH2-terminal amino acid sequencing revealed that inhibitory fractions eluted from a final, hydroxyapatite column contained prothrombin and osteopontin. Hydroxyapatite column fractions also contained other, unidentified protein inhibitors of calcium oxalate crystallization. CSBS contained also human serum albumin, alpha 1-acid glycoprotein, alpha 1-microglobulin, alpha 2-HS glycoprotein, retinol-binding protein, transferrin, and Tamm-Horsfall protein, but these proteins seemed to play no direct role in inhibitory activity.

Adult↗
PubMed1997

Possible association of infertility with sperm-specific abnormality of CD46.

Three infertile patients fulfilling normal or subnormal criteria on routine semen analysis showed abnormal sperm CD46 (membrane cofactor protein of complement) by SDS-PAGE/immunoblotting analysis using a panel of monoclonal antibodies. The sperm CD46 isoform has been reported to be associated with sperm-egg interaction. These three patients expressed normal CD46 isoforms on their lymphocytes and granulocytes. Sperm-specific abnormalities in these proteins thus parallel male infertility, suggesting a new category of infertility, probably due to aberrations in the molecules related to sperm-egg interaction.

Acrosome↗
PubMed1997

Effect of preinduction of heat shock proteins on acetic acid-induced colitis in rats.

In order to study the cytoprotective function of heat shock proteins (HSPs) in vivo, the effect of preinduction of HSPs by hyperthermia on acetic acid-induced colitis was investigated. Expression of 60-kDa, 72-kDa, and 90-kDa heat shock proteins (HSP60, HSP72, and HSP90, respectively) in rat colonic mucosa was investigated by Western blot analysis and immunohistochemical study before and after hyperthermia. Following pretreatment with or without hyperthermia, the rats received intrarectal infusion of various doses of acetic acid. The colonic mucosal damage was evaluated by macroscopic and microscopic assessments 24 hr after the intrarectal infusion of acetic acid. Expression of HSPs was significantly increased by hyperthermia in rat colonic mucosa. Immunohistochemical study also showed the increments of HSPs in the colonic mucosal cells after hyperthermia. Acetic acid-induced colitis was dramatically prevented by pretreatment with hyperthermia when HSP72 and HSP90 were preinduced. On the other hand, induction of HSP60 did not correlate with mucosal protection. Our findings suggest that HSP72 and HSP90 may have cytoprotective function against acetic acid-induced mucosal damage. These results may be important for understanding the mechanism of "adaptive cytoprotection" mediated by HSPs.

Acetic Acid↗
PubMed1997

Differential induction of HSP60 and HSP72 by different stress situations in rats. Correlation with cerulein-induced pancreatitis.

We previously reported that water-immersion stress specifically induced the synthesis of a 60-kDa heat-shock protein (HSP60, chaperonin homolog) in pancreatic cells and preinduction of HSP60 completely prevented development of cerulein-induced pancreatitis in the rat in an HSP60 quantitatively dependent manner. In order to study the cytoprotective function of a 72-kDa heat-shock protein (HSP72, stress-inducible hsp70), the effect of specific preinduction of HSP72 by hyperthermia on cerulein-induced pancreatitis was investigated and compared with the effect of preinduction of HSP60 in this study. Expression of HSP60 and HSP72 in the pancreas was investigated by immunoblot before and after water immersion or hyperthermia. Following pretreatment with water-immersion stress or hyperthermia, the rats were injected with cerulein (40 micrograms/kg, intraperitoneally). The pancreas wet weight and serum amylase concentration were measured before and after cerulein injection. Hyperthermia (42.5 degrees C, 20 min) specifically induced HSP72 in the pancreas. The synthesis of HSP60 was specifically induced by water-immersion stress in the pancreas. Cerulein-induced pancreatitis was clearly prevented by specific preinduction of HSP60 by water-immersion stress. However, preinduction of HSP72 by hyperthermia had no preventive effect on cerulein-induced pancreatitis. Our findings suggest that HSP60 and HSP72 have distinct functions in the pancreas, and their induction mechanisms are also different in vivo. These results could be important for understanding the mechanism of "adaptive cytoprotection" in the pancreas mediated by heat-shock proteins.

Amylases↗
PubMed1997

Induction of a 72-kDa heat shock protein and cytoprotection against thioacetamide-induced liver injury in rats.

Heat shock proteins are ubiquitous intracellular proteins induced by various physiological stress-related events. A 72-kDa heat shock protein (HSP72) has been reported to be an endogenous cytoprotectant in variety of cells in vitro. In order to study the cytoprotective function of HSP72 in the liver, the effect of preinduction of HSP72 in rat liver by systemic hyperthermia on thioacetamide-induced hepatic injury was investigated in this study. Expression of HSP72 in the liver was investigated by immunoblot and densitometric analysis. Rats were injected with thioacetamide (100 mg/kg, subcutaneously) with or without preinduction of HSP72 by hyperthermia. Serum AST and ALT concentrations were measured before and after thioacetamide injection in both group. Histologic alteration of the liver was evaluated also. Systemic hyperthermia (42.5 degrees C, 20 min) significantly induced HSP72 in the liver. Thioacetamide-induced hepatic injury was clearly prevented by preinduction of HSP72 by hyperthermia. Prevention of hepatocyte damage was more clear in the area around central veins where HSP72 induction was apparent. Our findings might suggest that HSP72 has an important function in the liver with respect to cytoprotection. These results might be important for understanding the mechanism of "adaptive cytoprotection" in the liver mediated by the function of heat shock proteins as "molecular chaperons" as reported in vitro.

Alanine Transaminase↗