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Biomedical subjects

N Suganuma

Publications and source records attributed to N Suganuma.

At least 19 recordsLinked to original sources
PubMed2003

The Lotus japonicus Sen1 gene controls rhizobial differentiation into nitrogen-fixing bacteroids in nodules.

A Lotus japonicus mutant, Ljsym75, which forms ineffective symbiotic nodules and defines a new locus involved in the process of nitrogen fixation, was characterized in detail in order to identify the stage of developmental arrest of the nodules. No nitrogen-fixing activity was detectable in Ljsym75 nodules at any stage during plant development, and plant growth was markedly retarded. Ljsym75 plants formed twice as many nodules as the wild-type Gifu, and this phenotype was not influenced by the application of low concentrations of nitrate. Although the ineffective nodules formed on Ljsym75 were anatomically similar to effective Gifu nodules, Ljsym75 nodules senesced prematurely. Microscopic examination revealed that bacteria endocytosed into Ljsym75 nodules failed to differentiate into bacteroids. Moreover, the bacteria contained no nitrogenase proteins, whereas leghemoglobin was detected in the cytosol of the nodules. These results indicate that Ljsym75 is required for bacterial differentiation into nitrogen-fixing bacteroids in nodules, and thus the Ljsym75 gene was renamed sen1 (for stationary endosymbiont nodule). Linkage analysis using DNA markers showed that Sen1 is located on chromosome 4.

Chromosome Mapping↗
PubMed2002

A survey of vaginal hysterectomy ending in laparotomy.

We did a retrospective study of 1,736 vaginal hysterectomies at Handa City Hospital from 1990 to 1999 with special reference to those 24 cases ending in laparotomy. The duration of operation, estimated blood loss, and uterine (with adnexal) weight of the failed vaginal hysterectomies were 139.1+/-42.9 min, 1,176.8+/-699.8 mL, 564.5+/-357.6 g, respectively. These values were significantly higher than those for the successful vaginal hysterectomies. Adhesions were seen in 14 cases (58.3%). Blood transfusion was required in 9 cases (37.5%). The most frequent cause for laparotomy was adhesions, followed by non-descent of the uterus. The decision to convert a vaginal hysterectomy into an abdominal procedure should be prompt because delay means the increased blood loss and a greater need for blood transfusions.

Adult↗
PubMed2002

Successful pregnancy in a patient having high basal serum levels of sex steroid hormones.

A 25-year-old infertile woman who had higher basal levels of serum progesterone (P) and estradiol (E(2)) was examined. Ultrasonography and gonadotropin-releasing hormone test suggested polycystic ovarian syndrome. The high serum E(2) and P concentration increased even more along follicle growth and after ovulation, respectively. Although the source of the higher levels of steroids was unclear, she became pregnant with artificial insemination of husband's sperm and luteal support with human chorionic gonadotropin administration, and delivered a healthy newborn. Through the present study, we can conclude that the high basal level of P in follicular phase may not always impair reproduction, although several reports stress that it adversely affects oocyte maturation and fertilization, and is harmful to endometrial receptivity.

Adult↗
PubMed2002

Pregnancy following placental abruption.

The aim of the present study by a retrospective chart review was to examine the recurrence rate after placental abruption. Between 1985 and 1998, 81 patients had a placental abruption. We had 2-year follow-up information about 31 patients and 27 of them had a total of 34 subsequent pregnancies. Recurrent placental abruption was observed in 6 pregnancies in 6 patients (6/27, 22.2%). Of the 6 recurrent placental abruptions, the gestational age was 1-3 weeks earlier than that of previous abruption in 4 patients. One patient delivered a healthy baby after her first abruption and then experienced a second abruption. We conclude that careful management is needed after 30 weeks in pregnant women with a previous history of placental abruption.

Abruptio Placentae↗
PubMed2001

Association of gastroesophageal reflux disease with weight gain and apnea, and their disturbance on sleep.

Obesity is a common predisposition to gastroesophageal reflux disease (GERD) and obstructive sleep apnea syndrome (OSAS). By statistical analysis of the respondents to a questionnaire that was distributed to members of the Kansai Rugby Association, we examined whether weight gain increased the incidence of these diseases and whether GERD alone disturbs sleep. Prevalence distribution of GERD by age differed from another survey, which suggests that predispositions other than age may contribute to GERD. Weight gain tended to increase the incidence of GERD. In our epidemiological study, both GERD (particularly nocturnal reflux) and OSAS significantly contributed to sleep disturbance. Although GERD alone seemed to be one of several independent factors of sleep disturbance, it was not a weak factor.

Adult↗
PubMed2001

Two types of pea leghemoglobin genes showing different O2-binding affinities and distinct patterns of spatial expression in nodules.

Five distinct cDNA clones for leghemoglobin (Lb) were isolated from pea (Pisum sativum) nodules. They were classified into two groups designated PsLbA and PsLbB according to sequence homology, O(2)-binding affinities of the recombinant proteins, and in situ localization of the mRNAs. The PsLbB group was comprised of four cDNA clones: PsLb120-1, -8, -29, and -34. They showed a high similarity of deduced amino acid sequences and O(2)-binding affinities of their recombinant proteins. Among them, the spatial expression pattern of PsLb120-1 was investigated in great detail, indicating that its transcripts were localized in the region from infection zone II to the distal part of nitrogen fixation zone III in effective nodules. PsLb5-10, which is the only cDNA clone of the PsLbA type, differed considerably from the PsLbB type in amino acid sequence, and the recombinant protein had a higher O(2)-binding affinity than those of the PsLbB type. The transcripts of PsLb5-10 were detected throughout the central tissue of effective nodules. However, in ineffective nodules on the pea mutant E135 (sym13), transcripts of PsLb5-10 were restricted to the distal portion of the central tissue as well as those of PsLb120-1. These findings indicate that the pea genome contains two types of Lb genes and suggest that they have different roles in the development of nitrogen-fixing symbiosis in pea nodules.

Amino Acid Sequence↗
PubMed2000

Additional N-glycosylation at Asn(13) rescues the human LHbeta-subunit from disulfide-linked aggregation.

CG, LH, FSH, and TSH are a family of heterodimeric glycoprotein hormones that contain a common alpha-subunit, but differ in their hormone-specific beta-subunits. Despite the considerable homology between LHbeta and CGbeta, we previously demonstrated that, when expressed in GH(3) cells, the secreted form of LHbeta showed mispaired disulfide-linked aggregation in addition to monomer, whereas no aggregation was observed in CGbeta. To determine the domains which are associated with the LHbeta-aggregation and which prevent CGbeta-aggregation, mutant beta-subunits in glycosylation and carboxy-terminus were expressed in GH(3) cells, and the occurrence of aggregation was assessed by continuous labeling with [35S]methionine/cysteine, immunoprecipitation with anti-hCGbeta serum, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a non-reducing condition. No aggregation was seen when N-linked oligosaccharides were attached to the Asn(13) of LHbeta. Removal of the carbohydrate unit at the Asn(13) of CGbeta caused aggregation, although the amount was less than 10% of monomer. The carboxy-terminal regions of neither LHbeta nor CGbeta were associated with their aggregation. Both CGbeta wild-type (WT) and CGbeta lacking N-glycosylation at Asn(13) (CGbeta-N13) showed aggregates in lysate. However, in contrast to CGbeta-N13, CGbetaWT revealed no aggregation in medium. These results indicate that the backbone structure consisting of 114 amino acids and N-linked glycosylation at Asn(30) is involved in the aggregation of LHbeta. Moreover, N-glycosylation at Asn(13) does not prevent such aggregation, but instead plays an important role in correct folding for both LHbeta- and CGbeta-subunits to be secreted as monomer.

Amino Acid Sequence↗
PubMed2000

Human chorionic gonadotropin beta-subunit affects the folding and glycosylation of alpha-cys mutants.

Human chorionic gonadotropin (hCG) is a member of a family of heterodimeric glycoprotein hormones that contain a common alpha-subunit but differ in their hormone-specific beta-subunits. Both subunits have five and six disulfide bonds, respectively, which consist of cystine knot structure. It is evident from numerous studies that the structure of beta-subunits is rigid, whereas that of alpha-subunit is flexible and can be molded by a beta-subunit. Previously, we reported that secreted forms of a mutants where either cysteine residue in the disulfide bond 7-31 or 59-87 was converted to alanine contained a disulfide-linked homodimer in addition to a monomer. To study whether the hCGbeta-subunit affects the conformations of alpha mutants, alpha-subunits lacking either the 7-31 or 59-87 disulfide bond were expressed with wild-type (WT) hCGbeta in Chinese hamster ovary cells, and homodimer formation and glycosylation of dimerized alpha-subunit were assessed by continuous labeling with [35S]methionine/cysteine, immunoprecipitation with anti-alpha or -hCGbeta serum, digestion with endoglycosidase-H or -F, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a non-reducing condition. Our data showed that a homodimer was not observed in the half-Cys mutants except one, where cysteine at position 7 was converted to alanine, in the presence of beta-subunit. This finding indicated that hCGbeta-subunit rescued the a half-Cys mutants from the formation of intermolecular disulfide-linked homodimer by preferentially combining with the alpha mutants. In both free WT and all mutants treated with endoglycosidase-H, no or faint bands were recognized as the same migration as seen in endoglycosidase-F treatment. Even in the endoglycosidase-H sensitive cases, the amount of sensitive alpha-subunits was less than 5% of total alpha-subunits. In contrast to free alpha-subunits, distinct endoglycosidase-H sensitive bands were seen in both WT and mutants, although the ratio was various. We concluded that hCGbeta-subunit affects the folding and glycosylation of the alpha-subunit mutants.

Amino Acid Substitution↗
PubMed2000

Epidemiological studies of coincidental outbreaks of enterohemorrhagic Escherichia coli O157:H7 infection and infectious gastroenteritis in Niimi City.

A sharp rise in the number of patients with infectious gastroenteritis was observed in the 25th week of year 1996 in the Takahashi-Ashin district by researchers with the Infectious Disease Surveillance Program for tuberculosis and other infectious diseases in the Okayama Prefecture. This sharp rise occurred coincidentally with an outbreak of enterohemorrhagic Escherichia coli O157:H7 (EHEC O157) infection in Niimi City of the Takahashi-Ashin district. However, this phenomenon of coincidental outbreaks was not observed during the outbreak of EHEC O157 infection in Oku Cho. By reviewing outpatients' charts in a sentinel hospital in Niimi City for the Infectious Disease Surveillance Program, it was noted that patients with acute gastrointestinal infection visiting the hospital during the increased incidence of infectious gastroenteritis may have been included as misclassified cases of EHEC O157 infection. On the other hand, the exponential probability plotting of symptomatic patients with EHEC O157 infection in Niimi City revealed a breaking point which suggested a dual exposure to contaminated food or an overlap with other acute gastrointestinal infections. The latter possibility was discounted, because stool culture-positive patients with EHEC O157 infection also exhibited a similar breaking point, and furthermore, the coincidental increase in infectious gastroenteritis in the same area was attributable to the EHEC O157 infection. The present study demonstrates the association between the sharp rise in gastroenteritis and the outbreak of EHEC O157 in the Takahashi-Ashin district. A careful analysis of the cases of infectious gastroenteritis by the Infectious Disease Surveillance Program would have predicted the outbreak of EHEC O157.

Disease Outbreaks↗
PubMed2000

The relationship between esophageal pressure and apnea hypopnea index in obstructive sleep apnea-hypopnea syndrome.

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in 34 patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). The OSAHS patients were diagnostically classified as having obstructive sleep apnea syndrome (OSAS) or upper airway resistance syndrome (UARS). Diagnosis of OSAS was based on an AHI of more than 5, and that of UARS on an AHI of less than 5, EEG arousals which were associated with apnea, hypopnea and/or respiratory effort occurring more than 10 times per hour, and daytime sleepiness. Negative Pes was represented by the greatest peak (NPes Max) and the number of increased (more than 13.5 cmH2O) episodes per hour (NPesI13.5). There was no significant correlation between the AHI and Pes indices, but NPes Max and NPesI13.5 showed significant correlation (p<0.01). NPes Max and NPesI13.5 showed no significant differences among the severe OSAS (AHI>50; 8 cases), moderate OSAS (50>AHI>15; 10 cases), mild OSAS (15>AHI>5; 9 cases) and UARS (7 cases) groups. We conclude that AHI does not reflect the severity of the increase in negative Pes, which is an important aspect of the pathophysiology of OSAHS. Assessment of OSAHS based on AHI alone may therefore underestimate the risk of increased negative Pes in cases with reduced AHI.

Electroencephalography↗
PubMed1999

Expression of asialoglycoprotein receptor in human fetal liver.

Asialoglycoprotein (ASGP) receptor, which exists in hepatic parenchymal cells, plays important roles in the clearance of desialylated glycoproteins from the circulation. To study the expression of ASGP receptor in human fetal liver, specimens were obtained after therapeutic/spontaneous abortion or at autopsy with informed consent. Reverse transcription polymerase chain reaction and immunohistochemical staining showed that ASGP receptor was present as early as 15 weeks of gestation in human fetal liver. In liver at 15 weeks-gestation it was stained uniformly in cytoplasm as seen in HepG2 cells. As gestation proceed the ASGP receptor was frequently observed on the cell surface and intracellular staining showed a spotted distribution. We conclude that the expression of ASGP receptor is an early event in the developmental process of fetal liver. Furthermore, the distribution of ASGP receptor changes as the liver develops.

Asialoglycoprotein Receptor↗
PubMed1999

Seroepidemiologic studies of hepatitis C virus infection in a population of Okayama Prefecture screened for liver disease.

To better understand the spread of hepatitis C virus (HCV) infection, we studied the association of HCV infection with similarly transmissible hepatitis B virus (HBV) infection and with hepatitis A virus (HAV) infection, which is supposed to be related to a nosocomial transmission of HCV. This was done by studying the presence or absence of antibodies to these viruses, as well as hepatitis B surface antigen, in a population of 1,398 inhabitants with abnormal liver function tests or history of liver disease and/or blood transfusion. This group was drawn from a group of 7,905 examinees screened for liver disease in 26 districts of Okayama prefecture, Japan. The prevalence of antibody-positive cases increased with age for those viruses. Small but significantly increased odds ratios were obtained among anti-HCV antibodies (HCVAb), anti-hepatitis B core antibodies (HBcAb) and anti-hepatitis A antibodies (HAVAb). After adjusting odds ratios by logistic regression analysis, a significant association was present only between HCVAb and HBcAb. The distribution of age-adjusted prevalences (AAP) of HCVAb in 26 districts was significantly wider than those of HBcAb or HAVAb. The district-based AAP of HCVAb, but not of HBcAb and HAVAb, correlated significantly with the district-based prevalence of infectious hepatitis having a tendency of chronicity reported in 1953-1955. Adjusted odds ratios calculated by logistic regression analysis of the virus markers showed that HCVAb was significantly associated with a past history of blood transfusion. Thus, the spread of HCV infection is speculated to have been triggered by blood transfusion, particularly from paid donors initially, followed by transmission by nosocomial or close person-to-person contact.

Adult↗
PubMed1998

Diagnosis of squamous cell carcinoma arising from mature cystic teratoma of the ovary.

BACKGROUND: The prognoses of patients with squamous cell carcinoma of the ovary are quite poor. However, preoperative diagnosis is difficult due to the rarity of this tumor and its similarity to mature cystic teratoma (MCT). The objective of this study was to assess the value of tumor markers and clinical characteristics in making a differential diagnosis between MCT and squamous cell carcinoma arising from MCT. METHODS: Between September 1979 and June 1996, 37 patients with ovarian squamous cell carcinoma arising from MCT were treated by the Tokai Ovarian Tumor Study Group. The authors evaluated tumor markers, tumor size, and age as parameters for differentiation between MCT and squamous cell carcinoma arising from MCT. Diagnostic efficiency was calculated as the sensitivity multiplied by the specificity. RESULTS: There were significant differences (P < or = 0.0002) in age, tumor size, and levels of squamous cell carcinoma antigen (SCC), CA125, and CEA, as well as a significant difference (P < or = 0.0396) in the CA19-9 level between MCT and squamous cell carcinoma arising from MCT. Diagnostic efficiency was highest for SCC (63.0%), followed by CA125 (50.7%). Receiver operating characteristic (ROC) curves demonstrated that CEA was the best screening marker for squamous cell carcinoma arising from MCT, whereas age and tumor size were better markers than CA125 or CA19-9. The optimal cutoff values for age and tumor size were 45 years and 99 mm, respectively, according to ROC analysis. CONCLUSIONS: These findings demonstrate that age and tumor size are important factors in making a differential diagnosis. In addition, SCC and CEA levels should be measured in patients age 45 years or older who have an MCT-like ovarian tumor larger than 99 mm in greatest dimension.

Adult↗
PubMed1998

Hepatocyte growth factor in human amniotic fluid promotes the migration of fetal small intestinal epithelial cells.

OBJECTIVE: Previously we reported on the abundant existence of hepatocyte growth factor in amniotic fluid. This study was conducted to clarify the effects of hepatocyte growth factor in amniotic fluid on fetal intestinal epithelial cells. STUDY DESIGN: Amniotic fluid samples were obtained from 22 cases at various gestational ages. The effects of amniotic fluid and recombinant human hepatocyte growth factor on proliferation, migration, and morphogenesis of intestine 407 cells (a cell line derived from fetal intestinal epithelial cells) were investigated. RESULTS: The mobility of intestine 407 cells was stimulated by amniotic fluid in proportion to the concentration of hepatocyte growth factor in amniotic fluid with the same effect observed with recombinant human hepatocyte growth factor. This activity was neutralized by addition of antihuman hepatocyte growth factor antibody. Neither increased deoxyribonucleic acid synthesis nor morphogenesis in response to amniotic fluid was identified under the conditions used. CONCLUSION: Amniotic fluid stimulates intestinal epithelial cell migration by way of hepatocyte growth factor in amniotic fluid during development of the fetal intestine.

Amniotic Fluid↗
PubMed1998

Inductions of immediate early genes (IEGS) and ref-1 by human chorionic gonadotropin in murine Leydig cell line (MA-10).

The effect of human chorionic gonadotropin (hCG) on the expression of immediate early genes (IEGs) including all members of fos and jun family, and c-myc was studied using mouse Leydig cell line (MA-10 cells) by Northern blot analyses. In addition, the induction of ref-1 which enhances DNA binding of fos/jun proteins was also analyzed. HCG induced a rapid and transient expression of c-fos, fosB, c-jun, junB, junD and c-myc with a peak at 30 min to 1 h. In contrast, induction of fra-1 mRNA was delayed with a peak at 3 hr. However, fra-2 mRNA was immediately increased by hCG with a peak at 1 h. The ref-1 mRNA was expressed before the stimulation and its level was not altered by hCG at least for 8 hr. The differential induction of IEGs and continuous expression of ref-1 mRNA suggest an important role of their gene products on the regulation of Leydig cell function by hCG.

Animals↗