Search PubMed⌕ Search

Biomedical subjects

R Nakano

Publications and source records attributed to R Nakano.

At least 127 records · Page 7Linked to original sources
PubMed1995

Sources of inhibin in early pregnancy.

Inhibin is a glycoprotein which suppresses the release of follicle stimulating hormone (FSH) from the pituitary. Plasma immunoreactive inhibin levels during pregnancy have been reported to be higher than those during the normal menstrual cycle. In the present study, we investigated the cellular localization of inhibin alpha-, beta A-, and beta B-subunits in the human corpus luteum and placenta during early pregnancy. Luteal cells and theca luteal cells in the corpus luteum of pregnancy exhibited positive staining for all three inhibin subunits. We also observed positive staining with antisera against each inhibin subunit in the syncytiotrophoblast, but not in the cytotrophoblast, in the villi during early pregnancy. The staining with antisera against inhibin alpha- and beta A-subunits was clearly observed, whereas the staining for the beta B-subunit was faint. These results suggest that the gestational corpus luteum and the villous tissue may be major sources of inhibin during early pregnancy.

Corpus Luteum↗
PubMed1994

A novel mutation in Cu/Zn superoxide dismutase gene in Japanese familial amyotrophic lateral sclerosis.

Recently, several missense mutations in the Cu/Zn superoxide dismutase gene (SOD1) have been reported as a putative cause of chromosome-21q-linked familial amyotrophic lateral sclerosis (FALS). We have discovered a novel missense mutation (substitution of Thr for Ala4) in exon 1 (GCC to ACC) in two FALS patients from one Japanese FALS family. No mutations were found in 17 cases of sporadic ALS. The enzyme activity of recombinant fusion protein containing the Cu/Zn superoxide dismutase (SOD) with the Ala4-to-Thr mutation was significantly reduced in E. coli. On the other hand, in the expression system in insect cells using Baculovirus, the mutant SOD expressed an enzyme activity as high as wild-type SOD. These results suggest that the stability of SOD with the Ala4-to-Thr mutation is disrupted especially in the fusion protein. Autopsy was carried out on one of the two patients, and the pathological findings were typical of FALS with posterior column involvement. These results raise the possibility that mutation of the SOD1 is responsible for FALS with broader pathological involvement.

Amino Acid Sequence↗
PubMed1994

Phosphorylation-dependent interaction of adenovirus preterminal protein with the viral origin of DNA replication.

Adenovirus preterminal protein (pTP) exists as a heterodimer with the viral DNA polymerase (AdPol) and becomes covalently linked to a dCMP residue during initiation of DNA replication. The in vivo phosphorylation of pTP could be demonstrated when pTP is overproduced using recombinant vaccinia viruses, or by a large scale metabolic labeling of adenovirus 2 (Ad2)-infected HeLa cells. Phosphoserine was the only phosphoamino acid obtained by acid hydrolysis of 32P-labeled pTP immunoprecipitated from metabolically labeled HeLa cells infected with either Ad2 or recombinant vaccinia virus. Tryptic peptide maps of pTP expressed using recombinant vaccinia virus system in HeLa cells revealed that phosphorylation of pTP occurred on multiple sites. Dephosphorylation of pTP with calf intestinal alkaline phosphatase resulted in a significant decrease in its activity in the in vitro DNA replication initiation assays. Further characterization of the phosphatase-treated pTP indicated that although dephosphorylation did not affect its interaction with AdPol, the specific recognition of the DNA replication origin by pTP was significantly reduced as determined by gel electrophoresis-based DNA mobility shift assays.

Adenoviruses, Human↗
PubMed1994

Ambient pressure stimulates immortalized human aortic endothelial cells to increase DNA synthesis and matrix metalloproteinase 1 (tissue collagenase) production.

In the present study, we investigated the effect of ambient pressure on [3H]-thymidine incorporation and on the production of matrix metalloproteinase 1 (tissue collagenase/proMMP-1) using human aortic endothelial cells immortalized with simian virus 40 (SE-1). Incubation of cells at ambient pressures of 50 and 100 mmHg for 24 h slightly increased [3H]-thymidine incorporation when directly compared with normal culture conditions. The amount of [3H]-thymidine incorporated in SE-1 reached a maximum at 150 mmHg, while a further increase in pressure to 200 mmHg decreased incorporation. The same ambient pressure slightly stimulated human aortic intimal smooth muscle cells (SMC) to increase [3H]-thymidine incorporation but not medial SMC. Immunoblot analysis also showed that ambient pressure, ranging from 50 to 200 mmHg, like 12-O-tetradecanoyl-phorbol-13-acetate stimulated SE-1 to produce proMMP-1, an effect not seen with either intimal or medial SMC. The amount of proMMP-1 produced also reached a maximum level at 150 mmHg. We postulate that human endothelial cells are ambient pressure sensitive and that relatively lower ambient pressures play an important role in the growth of endothelial cells, while higher pressures injure endothelial cells, resulting in the initiation of atherosclerosis. This cell line may prove useful in the investigation of both the physiological and pathological roles of blood pressure on endothelial cell function.

Aorta↗
PubMed1994

Familial amyotrophic lateral sclerosis with a mutation in the Cu/Zn superoxide dismutase gene.

Several missense mutations within exons 1, 2, 4 and 5 of the gene for Cu/Zn-binding superoxide dismutase (SOD1) have been discovered to be involved in the development of chromosome 21q-linked familial amyotrophic lateral sclerosis (FALS). We describe here an autopsied patient with FALS, in whom we have recently identified a novel missense mutation in exon 1 of the SOD1 gene. The neuropathological findings were compatible with those described previously in patients with FALS with posterior column involvement. This suggests that mutations of the SOD1 gene may be responsible for this form of FALS.

Adult↗
PubMed1994

Purification of high-molecular-weight follicle-stimulating hormone binding inhibitor in porcine follicular fluids.

We performed the purification of high-molecular-weight follicle-stimulating hormone binding inhibitor (FSHBI) from porcine follicular fluids. The FSHBI activities of high-molecular-weight fractions acquired by ultrafiltration of follicular fluids from small, medium and large follicles with Centriflo CF25 membrane cone were 277.2 +/- 24.6, 176.7 +/- 3.0 and 141.3 +/- 3.6 U, respectively. By affinity chromatography of CF25 retentate with a column of Blue Sepharose CL6B, 94.1 +/- 5.3% of FSHBI activity was recovered in the unretained fraction. The FSHBI in the unretained fraction was purified by anion-exchange chromatography with a column of Mono Q and gel filtration on Sephacryl S300HR. As a result of sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) of the final purified fraction, a single silver-stained band was observed at 310 kD under the non-reducing conditions. On the other hand, under the reducing conditions, SDS-PAGE revealed three bands at 178, 101 and 55 kD. A double reciprocal plot analysis of this substance showed competitive inhibition in FSH binding. The results of the present study suggest the existence of a 310 kD FSHBI composed of three subunits of 178, 101 and 55 kD in porcine follicular fluids.

Animals↗
PubMed1994

FSH and LH up-regulate epidermal growth factor receptors in rat granulosa cells.

Epidermal growth factor (EGF) modulates ovarian folliculogenesis and steroidogenesis and its binding sites have been demonstrated in the ovary. We investigated the localization of EGF-binding sites in the rat ovary, and the effects of FSH and LH on EGF binding to cultured granulosa cells. Autoradiographic localization of 125I-labelled mouse EGF-binding sites was demonstrated in the granulosa and luteal cells. Displacement study and Scatchard analysis showed that a single class of specific binding sites for 125I-labelled mouse EGF was present in the granulosa cells, obtained from the ovaries of immature rats treated with diethylstilbestrol. The number of binding sites and the apparent dissociation constant were 4336 binding sites/cell and 3.42 pmol/l respectively. The granulosa cells were cultured for 48 h at 37 degrees C in medium alone or with increasing amounts of ovine FSH (oFSH; 1-1000 micrograms/l). FSH treatment increased 125I-labelled mouse EGF binding to the granulosa cells in a dose-dependent manner. After culture with oFSH (100 micrograms/l) for 48 h, the cells were cultured in medium alone or with increasing amounts of ovine LH (oLH; 1-1000 micrograms/l) for an additional 48 h. LH treatment also increased 125I-labelled mouse EGF binding in a dose-dependent manner, compared with the control. However, neither FSH nor LH altered receptor-binding affinity. Furthermore, after culture with oFSH (FSH-primed) or oFSH followed by oLH (LH-primed), tissue plasminogen activator (tPA) activities in the conditioned media were examined by fibrin autography.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

[A patient with aneurysm of extracranial internal carotid artery presenting lower cranial polyneuropathy similar to Tapia's syndrome].

Tapia's syndrome, first described in 1904 by A.G. Tapia, is considered to be a syndrome consisting of ipsilateral hemiplegia of larynx and tongue with spared movement of soft palate. A 61-year-old Japanese woman had been in good health until August 1991, when she developed hoarseness and atrophy of the left side of her tongue. Although she also showed mild disturbance of elevation of bilateral soft palates and loss of taste in the posterior third of her tongue as well, the main symptoms were the paralyses of the ipsilateral larynx and tongue without involvement of the ipsilateral sternocleidomastoid and trapezius muscles. We concluded that she had cranial polyneuropathy similar to that of Tapia's syndrome. A carotid angiography revealed that she has a large aneurysm, which originated from the extracranial internal carotid artery in the region near the skull base. No other abnormal findings were detected by any computed tomography, magnetic resonance imaging or 67Ga-scintigraphy. The patient's lower cranial polyneuropathy was considered to be caused by the aneurysm. A survey of the literature indicates that extracranial carotid aneurysm is an extremely rare cause of Tapia's syndrome. In this case, the location of the aneurysm, which was present considerably distant from the skull base, seems to be the reason for the sparing of the accessory nerve.

Aneurysm↗
PubMed1994

[Paraneoplastic cerebellar degeneration].

Paraneoplastic cerebellar degeneration (PCD) is a rare manifestation of cancer, characterized clinically by subacute progressive ataxia, dysarthria and nystagmus. The pathological hallmark of PCD is a severe, diffuse loss of Purkinje cells. PCD occurs most frequently in association with small cell carcinoma of the lung and adenocarcinoma of the ovary, but it has also developed in patients with carcinoma of the breast, malignant lymphoma, and various cancers. Autoantibodies against cerebellar Purkinje cells have been frequently observed in the serum or cerebrospinal fluid (CSF) from patients with PCD. The cause of PCD is unknown, but the presence of these autoantibodies in some patients suggests that the pathogenesis may be immune mediated. The potential role of the autoantibody in the pathogenesis of PCD is discussed.

Autoantibodies↗
PubMed1993

Adenovirus DNA polymerase is a phosphoprotein.

Biological activities of many of the eukaryotic DNA replication proteins are modulated by protein phosphorylation. Investigations of the phosphorylation of adenovirus DNA polymerase (AdPol) have been difficult mainly because of its low level of synthesis in adenovirus-infected HeLa cells. However, when AdPol was overproduced using the recombinant vaccinia virus (RV-AdPol) and the baculovirus expression systems, or by a large scale metabolic labeling of adenovirus 2-infected HeLa cells (native AdPol), in vivo phosphorylation of AdPol could be demonstrated. Phosphoamino acid analysis of [32P]AdPol indicated the presence of phosphoserine independent of the source of AdPol. Comparison of tryptic peptide maps of native AdPol and RV-AdPol revealed that the majority of phosphopeptides were common. Fractionation by high performance liquid chromatography and sequencing of one of the major phosphopeptides revealed serine 67 as a site of phosphorylation. Interestingly, this site is located close to the nuclear localization signal of AdPol and has a consensus substrate recognition sequence for histone H1 (cdc2-related) kinases and mitogen-activated protein kinases. Dephosphorylation of AdPol with calf intestinal alkaline phosphatase resulted in significant decrease in its activity in the in vitro DNA replication initiation assay, suggesting that phosphorylation is important for its biological activity.

Adenoviruses, Human↗
PubMed1993

Expression of the large myelin-associated glycoprotein isoform in rat oligodendrocytes around cerebral infarcts.

An immunohistochemical method that uses two specific antisera-distinguishable myelin-associated glycoprotein (MAG) isoforms showed an expression of large MAG isoform (L-MAG) protein in the oligodendrocyte cytoplasms in the white matter around experimental cerebral infarcts produced by occlusion of the left middle cerebral artery in the rat. L-MAG protein also was detected in the white matter on the contralateral side. This protein appears prior to S-MAG protein in myelination and remyelination in the central and peripheral nervous systems, and is believed to function in myelin formation. Because L-MAG protein has been found in the oligodendrocyte cytoplasm only in the early development period, its appearance in this cytoplasm after ischemic insult is evidence of MAG regeneration.

Animals↗
PubMed1993

Expression of myelin-associated glycoprotein isoforms after sciatic nerve crush injury in mice.

The large myelin-associated glycoprotein isoform (L-MAG) protein and small myelin-associated glycoprotein isoform (S-MAG) protein were demonstrated after sciatic nerve crush injury in mice by an immunoblotting technique using specific antibodies to the L-MAG protein and the S-MAG protein, respectively. Immunoblots indicated a rapid decrease in expression of both isoform proteins in the crushed sciatic nerves to < 10% of the control side. By 13 d after injury, L-MAG protein expression had quickly recovered to 100% of the control level. Following the increase in L-MAG protein expression, S-MAG protein expression recovered to 100% by 20 d after injury. It has been reported that the developmental maximum expression of L-MAG protein precedes that of S-MAG protein in both central and peripheral nervous system (CNS and PNS). Our previous work demonstrated that L-MAG mRNA was characteristically induced at the time of most active myelination, including remyelination in the CNS. We here have shown the expression of L-MAG protein precedes that of S-MAG protein during active remyelination in the PNS. This suggests that it plays an important role in the early stage of myelin formation.

Animals↗
PubMed1993

Production of matrix metalloproteinase 9 (92-kDa gelatinase) by human oesophageal squamous cell carcinoma in response to epidermal growth factor.

We demonstrated that four human oesophageal squamous cell carcinoma cell lines (TE8, TE9, TE10 and TE11) produced matrix metalloproteinase-1 (proMMP-1/tissue collagenase), 2 (ProMMP-2/'type IV collagenase'), 3 (proMMP-3/stromelysin), and 9 (proMMP-9/92-kDa gelatinase) as members of a matrix metalloproteinase (MMP) family, which degrades extracellular matrix macromolecules. Under normal culture conditions, in immunoblot analysis, proMMP-1 of M(r) = 53,00 was detected in one cell line (TE8), proMMP-2 of M(r) = 72,000 in three cell lines (TE9, TE10, and TE11), and proMMP-3 of M(r) = 57,000 in all four cell lines. In addition to these enzymes, in enzymography, a gelatinolytic activity around M(r) = 92-kDa, likely to be proMMP-9, was detected in only one cell line (TE10) under normal culture conditions. When these cell lines were treated with epidermal growth factor (EGF), however, the agent stimulated three cell lines (TE8, TE10 and TE11) to produce proMMP-9 in a dose-dose dependent manner. Oesophageal carcinoma-conditioned medium stimulated oesophageal fibroblasts to produce proMMP-1, -2, and -3, suggesting that the interaction between oesophageal carcinoma and stromal fibroblasts also plays a role in the production of MMPs by the latter. Our present study illustrates that oesophageal squamous cell carcinoma produces a variety of MMPs including proMMP-1, -2, -3, and -9 in vitro, suggesting that the ability of MMP production of the tumour may play an important role in its malignant behaviour and that the production of proMMP-9 may be regulated by EGF via overexpression of EGF receptors.

Carcinoma, Squamous Cell↗
PubMed1993

In vitro effects of ethanol on gonadotropin-binding sites in porcine granulosa cells.

In this study, we examined the in vitro effects of ethanol on [125I]human follicle-stimulating hormone (hFSH) and [125I]human luteinizing hormone (hLH) binding to porcine granulosa cells (GCs). The GC suspensions and [125I]hFSH or [125I]hLH were incubated in the presence or absence of 1-50% (vol/vol) ethanol until steady state binding was attained for 2 h at 37 degrees C. The presence of 1-4% ethanol significantly enhanced the specific binding of hFSH to porcine GCs, with a maximal effect at 4% ethanol, however, had no effect on hLH binding. Higher concentration of ethanol (8-50%) significantly decreased both specific hFSH and hLH binding to porcine GCs. Scatchard analyses revealed that ethanol increased the number of FSH-binding sites without changing the affinity for FSH. The data suggest that porcine GCs contain a population of masked FSH-binding sites exposed by in vitro treatment with ethanol. Furthermore, the membrane fluidity may play an important role in the masking/unmasking mechanism of FSH-binding sites within the porcine GCs.

Animals↗
PubMed1993

Diagnosis and treatment of proximal tubal obstruction by fluoroscopic transcervical fallopian tube catheterization.

The efficacy of fluoroscopic transcervical Fallopian tube catheterization in treating patients with proximal tubal obstruction was investigated. In 11 (15.9%) of the 69 patients who entered the study, patency of the proximal Fallopian tubes was shown by a pre-treatment hysterosalpingogram or an ostial selective salpingogram. Transcervical Fallopian tube catheterization attested to the success of recanalization in at least one of the obstructed tubes in 41 of our 58 patients (70.7%). Of 92 obstructed tubes, 56 (60.9%) were successfully recanalized. However, normal tubal visualization was possible in only 13 tubes (23.2%). Most of the recanalized tubes were considered to be peritubal adhesions (64.3%). Eight of 36 (22.2%) patients who had been successfully recanalized achieved pregnancies; 12 patients demonstrated normally appearing salpingograms after the procedure, and five (41.7%) had an intra-uterine pregnancy. Suspected peritubal adhesions were exhibited on post-operative salpingograms of 24 patients, one of whom had an intra-uterine pregnancy, while two had tubal pregnancies. Transcervical Fallopian tube catheterization is a simple and effective method for evaluating and treating proximal tubal obstruction. Most of the patients (70.7%) in whom recanalization was successful showed significant signs of distal tubal damage. This procedure can also be used to arrive at a prognosis regarding conception.

Adult↗
PubMed1993

Possible involvement of protein kinase C in gonadotropin-induced ovulation in the rat ovary.

Recent reports indicate that protein kinase C may play an important role in the process of gonadotropin-induced ovulation in the ovary. In the present study, we examined the effect of the protein kinase C inhibitor, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7), on LH-stimulated tissue type plasminogen activator (tPA) activity in cultured rat granulosa cells. Granulosa cells were obtained from PMSG-treated rats and cultured for 48 h in the presence or absence of H-7 (0.1-60 microM) with ovine LH (30 ng/ml), phorbol 12-myristate 13-acetate (10(-8) M), phorbol 12,13-dibutyrate (10(-8) M), or (Bu)2cAMP (5 mM). After culture, tPA activity in the conditioned medium was assayed by fibrin autography technique after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. H-7 (1.0-60 microM) inhibited LH-, phorbol 12-myristate 13-acetate-, or phorbol 12,13-dibutyrate-stimulated tPA activity dose dependently, and each ID50 was approximately 8 microM. However, H-7 did not inhibit (Bu)2cAMP-stimulated tPA activity. To investigate the effect of H-7 on the ovulatory process in vivo, PMSG-treated immature rats were injected with H-7 (10(-9)-10(-3) M) into the unilateral ovarian bursa just before human CG administration. After 24 h, the number of oocyte-cumulus complexes in the oviduct was counted. H-7 suppressed the number of oocytes released from treated ovaries dose-dependently. The light microscopical observation revealed that ovaries treated with H-7 contained a few corpora lutea and many large unruptured follicles. The results of the present study suggest that the suppressive effects of H-7 on human CG-induced ovulation might be partly due to the inhibition of tPA secretion by rat granulosa cells via protein kinase C inhibition.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗