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Biomedical subjects

S Shima

Publications and source records attributed to S Shima.

At least 19 recordsLinked to original sources
PubMed1997

Formylmethanofuran: tetrahydromethanopterin formyltransferase from Methanopyrus kandleri - new insights into salt-dependence and thermostability.

BACKGROUND: Formylmethanofuran: tetrahydromethanopterin formyltransferase (Ftr) from the methanogenic Archaeon Methanopyrus kandleri (optimum growth temperature 98 degrees C) is a hyperthermophilic enzyme that is absolutely dependent on the presence of lyotropic salts for activity and thermostability. The enzyme is involved in the pathway of carbon dioxide reduction to methane and catalyzes the transfer of formyl from formylmethanofuran to tetrahydromethanopterin. RESULTS: The crystal structure of Ftr, determined to a resolution of 1:73 AE reveals a homotetramer composed essentially of two dimers. Each subunit is subdivided into two tightly associated lobes both consisting of a predominantly antiparallel beta sheet flanked by alpha helices forming an alpha/beta sandwich structure. The approximate location of the active site was detected in a region close to the dimer interface. CONCLUSIONS: The adaptation of Ftr against high lyotropic salt concentrations is structurally reflected by a large number of negatively charged residues and their high local concentration on the surface of the protein. The salt-dependent thermostability of Ftr might be explained on a molecular basis by ionic interactions at the protein surface, involving both protein and inorganic salt ions, and the mainly hydrophobic interactions between the subunits and within the core.

Amino Acid Sequence↗
PubMed1997

Premenstrual mood changes and maternal mental health in pregnancy and the postpartum period.

To investigate the relationship between premenstrual mood changes and maternal mental health in the perinatal period, a prospective questionnaire survey of 1,329 women was carried out. Women with a premenstrual mood changes (irritability) before pregnancy showed significantly higher Zung's Self-rating Depression Scale (SDS) scores than those without it, throughout pregnancy and the postpartum period (6 time points: early, middle, and late pregnancy, 5 days, 1 month, and 6 months after childbirth). In addition, women with premenstrual irritability had greater anxiety about pregnancy and delivery, were more reluctant to accept mother roles, and felt their babies (fetuses or neonates) were more vulnerable. These findings suggest that premenstrual mood change is correlated with unstable mental health throughout the perinatal period.

Adolescent↗
PubMed1997

Crystallization and preliminary X-ray diffraction studies of methyl-coenzyme M reductase from methanobacterium thermoautotrophicum.

Methyl-coenzyme M reductase isoenzyme I from the methanogenic Archaeon, Methanobacterium thermoautotrophicum (strain Marburg), was crystallized by vapor diffusion methods. Crystal form M obtained with 2-methyl-2,4-pentanediol as the precipitant displayed space group P2(1), with unit cell parameters of a=83.2 A, b=117.4 A, c=125.1 A, and beta= 92.6 degrees, and diffracted at better than 2.8 A resolution. Crystal form P grown from polyethylene glycol 400 belonged to space group P2(1), and had unit cell parameters of a=83.1 A, b=120.2 A, c=123.1 A, and beta=91.7 degrees, diffracting at least to 1.7 A resolution. Both crystal forms have one molecule per asymmetric unit and are suitable for X-ray structure analysis.

Crystallization↗
PubMed1997

The efficacy of antidepressants in post-stroke depression.

The aim of the present study was to confirm the efficacy of antidepressants in post-stroke depression and to identify the factors related to outcome. Subjects consisted of 20 inpatients suffering from post-stroke in a rehabilitation hospital. The subjects were treated with various antidepressants, mainly imipramine, amitriptyline, and amoxapine. After 4 weeks of treatment, 13 showed some improvement; significant improvement in 5, moderate improvement in 5, mild improvement in 3 by a clinical global impression. Whereas all the patients aged less than 65 yr were responders, only 3 of the 10 patients over 65 yr were responders. All of the male patients, but only half of the female patients, were responders. With regards to the presence of a spouse, 13 of the 16 patients with a spouse, but none of 4 patients without, showed a response. No significant correlation was found between the occurrence of each depressive symptom and outcome. Thus, the responders were younger and had better social support in comparison with the non-responders. This result implies that antidepressants are effective for post-stroke depression.

Adult↗
PubMed1996

Crystallization and preliminary X-ray diffraction studies of formylmethanofuran: tetrahydromethanopterin formyltransferase from Methanopyrus kandleri.

Formylmethanofuran:tetrahydromethanopterin formyltransferase from the hyperthermophilic methanogenic Archaeon Methanopyrus kandleri (growth temperature optimum 98 degrees C) was crystallized by vapor diffusion methods. Crystal form M obtained with 2-methyl-2,4-pentanediol as precipitant displayed the space group P2(1) with unit cell parameters of a = 87.0 A, b = 75.4 A, c = 104.7 A, and beta = 113.9 degrees and diffracted better than 2 A resolution. Crystal form P grown from polyethylene glycol 8000 belonged to the space group I4(1)22 and had unit cell parameters of 157.5 A and 242.1 A. Diffraction data to 1.73 A were recorded. Crystal form S which was crystallized from (NH4)2SO4 in the space group I4(1)22 with unit cell parameters of 151.3 A and 249.5 A diffracted at least to 2.2 A resolution. All crystal forms probably have four molecules per asymmetric unit and are suitable for X-ray structure analysis.

Archaea↗
PubMed1996

Adenoid cystic carcinoma of the esophagus: report of a case and review of the Japanese literature.

We report herein the case of a 79-year-old man with adenoid cystic carcinoma (ACC) of the esophagus. The tumor had a polypoid appearance and was covered by thin esophageal mucosa. As the biopsy specimens suggested a diagnosis of poorly differentiated adenocarcinoma, the patient underwent subtotal esophagectomy with reconstruction of the gastric tube via the posterior mediastinum. Histologically, the carcinoma contained basaloid cells, cribriform foci, and a certain amount of eosinophilic hyaline substance. Some of the basaloid cells were stained immunohistochemically for keratin, muscle actin, and S-100 protein, a pattern which was identical to the pattern of immunoreactivity of the myoepithelium. We reviewed 36 other cases of ACC of the esophagus reported in Japan, with special reference to the criteria for histological diagnosis.

Aged↗
PubMed1996

Primary structure and properties of the formyltransferase from the mesophilic Methanosarcina barkeri: comparison with the enzymes from thermophilic and hyperthermophilic methanogens.

The ftr gene encoding formylmethanofuran: tetrahydromethanopterin formyltransferase (Ftr) from Methanosarcina barkeri was cloned, sequenced, and functionally expressed in Escherichia coli. The overproduced enzyme was purified eightfold to apparent homogeneity, and its catalytic properties were determined. The primary structure and the hydropathic character of the formyltransferase from Methanosarcina barkeri were compared with those of the enzymes from Methanobacterium thermoautotrophicum, Methanothermus fervidus, and Methanopyrus kandleri. The amino acid sequence of the enzyme from Methanosarcina barkeri was 64%, 61%, and 59% identical to that of the enzyme from Methanobacterium thermoautotrophicum, Methanothermus fervidus, and Methanopyrus kandleri, respectively. A negative correlation between the hydrophobicity of the enzymes and both the growth temperature optimum and the intracellular salt concentration of the four organisms was observed. The hydrophobicity of amino acid composition was +21.6 for the enzyme from Methanosarcina barkeri (growth temperature optimum 37 degrees C, intracellular salt concentrationapproximately 0.3 M), +9.9 for the enzyme from Methanobacterium thermoautotrophicum (65 degrees C,approximately 0.7 M), -20.8 for the enzyme from Methanothermus fervidus (83 degrees C,approximately 1.0 M) and -31.4 for the enzyme from Methanopyrus kandleri (98 degrees C, > 1.1 M). Generally, a positive correlation between hydrophobicity and thermophilicity of enzymes and a negative correlation between hydrophobicity and halophilicity of enzymes are observed. The findings therefore indicate that the hydropathic character of the formyltransferases compared is mainly determined by the intracellular salt concentration rather than by temperature. Sequence similarities between the formyltransferases from methanogens and an open reading frame from Methylobacterium extorquens AM1 are discussed.

Amino Acid Sequence↗
PubMed1996

Clinical and psychosocial correlates of antenatal depression: a review.

In contrast to the considerable research on postnatal depression, less attention has been paid to that occurring during pregnancy-antenatal depression (AD). However, recent investigations have studied depression among pregnant women not necessarily requiring psychiatric hospitalization but needing psychological support and help. A controlled study showed that the rate of AD was significantly higher than that of depression among non-pregnant women: the reported incidence varies between 4 and 29%. AD was found to be associated with: (1) obstetric factors (first pregnancy, first delivery, and past history of abortion); (2) early experience (loss of father); (3) personality (high neuroticism score); (4) attitudes towards the present pregnancy (perplexity of the husband); (5) accomodation factors (non-detached housing, and expected crowdedness after birth of the child, and (6) social support (low level of intimacy with the husband). Differential effects of these factors in the development of AD are to be studied in future research, particularly in conjunction with investigation of hormonal variables.

Depressive Disorder↗
PubMed1996

Psychosocial study of depression in early pregnancy.

BACKGROUND: The psychosocial correlates of depression during pregnancy were explored. METHOD: Pregnant women attending the antenatal clinic of a general hospital (n = 1329) received a set of questionnaires including Zung's Self-Rating Depression Score (SDS). SDS high scores (> 49) (the cases: n = 179) were compared with low scores (< 38) (the controls; n = 343). RESULTS: The cases were characterised by: first delivery; more nausea, vomiting, and anorexia; more menstrual pains and premenstrual irritability; early paternal loss; lower maternal care and higher paternal overprotection; higher public self-consciousness score; more smoking and use of medication in pregnancy; unwanted pregnancy; negative psychological response to the pregnancy by the woman and husband; poor intimacy by the husband; and having remarried. CONCLUSIONS: Depression in early pregnancy is determined mainly by psychosocial factors.

Adult↗
PubMed1996

[Availability of the Alcohol Use Disorders Identification Test (AUDIT) for a complete health examination in Japan].

OBJECTIVE: The Alcohol Use Disorders Identification Test (AUDIT) is an instrument designed to identify hazardous drinkers, harmful drinkers and alchoholics. It was translated into Japanese using the WHOQOL method. The concurrent validity and reliability of the Japanese version of AUDIT were evaluated in a complete health examination. The instrument was also compared with the CAGE questionnaire. METHOD: The subjects were 93 applicants attending for health checks in a human dry dock. They completed self-report questionnaires containing the Core AUDIT and CAGE. and underwent a semi-structured interview conducted by a professional physician. RESULT: From the semi-structured interview, it was determined that 23 of the subjects were problem drinkers and 10 were alcoholics. Analyses indicated that the Core AUDIT was sufficiently sensitive and specific for discriminating problem drinkers and alcoholics. Core AUDIT was also superior to CAGE for discriminating problem drinkers from non-problem drinkers, as well as identifying alcoholics. CONCLUSION: The data suggest that the Japanese version of AUDIT is useful for early detection of hazardous or harmful drinkers.

Aged↗
PubMed1995

Formylmethanofuran:tetrahydromethanopterin formyltransferase (Ftr) from the hyperthermophilic Methanopyrus kandleri. Cloning, sequencing and functional expression of the ftr gene and one-step purification of the enzyme overproduced in Escherichia coli.

Methanopyrus kandleri is a methanogenic Archaeon that grows on H2 and CO2 at a temperature optimum of 98 degrees C. The gene ftr encoding the formylmethanofuran:tetrahydromethanopterin formyltransferase, an enzyme involved in CO2 reduction to methane, has been cloned, sequenced, and overexpressed in Escherichia coli. The overproduced enzyme could be purified in yields above 90% by simply heating the cell extract to 90 degrees C in 1.5 M K2HPO4 pH 8.0 for 30 min. From 1 g wet cells (70 mg protein) approximately 14 mg formyltransferase was obtained. The purified enzyme showed essentially the same catalytic properties as that purified from M. kandleri cells. The primary structure and properties of the formyltransferase are compared with those of the enzyme from Methanobacterium thermoautotrophicum (growth temperature optimum 65 degrees C) and Methanothermus fervidus (83 degrees C). Of the three enzymes that from M. kandleri had the lowest isoelectric point (4.2) and the lowest hydrophobicity of the amino acid composition. The enzyme from M. kandleri had the relatively highest content in alanine, glutamate and glutamine and the relatively lowest content in isoleucine, leucine and lysine. These properties, some of which are unusual for enzymes from other hyperthermophilic organisms, may reflect that the formyltransferase from M. kandleri is adapted to both hyperthermophilic and halophilic conditions.

Amino Acid Sequence↗
PubMed1995

PCNA immunostaining combined with AgNOR staining in esophageal squamous cell carcinoma to identify patients with a poor prognosis.

Immunostaining of the proliferating cell nuclear antigen (PCNA) provides important information about cell kinetics and is easily performed on routinely obtained formalin-fixed, paraffin-embedded materials. We report herein the results of a retrospective study on PCNA staining in esophageal cancer undertaken to determine its significance. As this study indicated that immunoreactivity was preserved in specimens fixed within 24h, only 31 specimens from surgical patients were available for this investigation. The mean PCNA index of the patients without invasion to the adventitia (35.7 +/- 17.9) was significantly lower than that of those with invasion to the adventitia or neighboring structures (49.7 +/- 14.5), while the PCNA index did not correlate with other clinicopathologic parameters such as histologic type, lymph node metastases, or prognosis. However, when an analysis of PCNA staining was combined with an analysis of argyrophilic nucleolar organizer region (AgNOR) staining, a correlation with prognosis was found. In fact, seven patients with a high PCNA index (> or = 44) and AgNOR count (> or = 6) had a significantly poorer prognosis than the remaining 22 (P = 0.0014), and six of these seven patients died within 2 years. These results indicate that this combined evaluation may be useful for the identification of patients with a poor prognosis among those undergoing surgery for esophageal squamous cell carcinoma.

Adult↗
PubMed1995

Paget's disease of the esophagus. A case report with review of the literature.

A 59-year-old Japanese man with Paget's disease of the esophagus is reported. The epithelium in the upper-to-middle portion of the esophagus was extensively infiltrated by Paget's cells. There was a minimal submucosal invasive area showing features of undifferentiated carcinoma. Histochemical and immunohistochemical studies showed glandular differentiation of the intraepithelial Paget's cells. Electron microscopic study demonstrated distinctive intraepithelial growth of the Paget's cells with the formation of desmosomes with nonneoplastic squamous cells, but there was no definitive evidence of glandular differentiation of the Paget's cells. These findings suggest that the entity in this case was probably adenocarcinoma in situ originating in the components of the esophageal epithelium, such as the intraepithelial or other portions of the esophageal gland ducts, with focal invasion and anaplasia. The additional control study of 154 cases of esophageal carcinoma revealed two other cases showing localized pagetoid extensions.

Esophageal Neoplasms↗
PubMed1995

[A case of small cell lung cancer that developed during therapy for myasthenia gravis].

A 56-year-old man had been complaining of progressive proximal muscle weakness and bilateral ptosis before his first admission to our hospital. He received an injection of edrophonium chloride, which resulted in remarkable improvement of muscle strength. Electromyographic studies revealed a compound muscle action potential that decreased after repetitive stimulation at a high rate (15 Hz). He was regarded as having myasthenia gravis (MG) rather than Eaton-Lambert syndrome because of these findings. Eighteen months after successful treatment of MG with oral anticholinesterase medication, he complained of an abdominal mass. The mass was found to be a tumor that had metastasized from a primary small cell carcinoma of the lung. Cases of MG with small cell carcinoma of the lung seem to be very rare, and the details of the relationship between them remain unknown. In this patient, MG may have developed by paraneoplastic mechanisms. This hypothesis is interesting, since it has been demonstrated recently by molecular biological techniques that small cell carcinomas of the lung express nicotinic acetylcholine receptors.

Carcinoma, Small Cell↗
PubMed1994

The phylogenetic position of Hydrogenobacter acidophilus based on 16S rRNA sequence analysis.

Hydrogenobacter acidophilus strain 3H-1 is a thermoacidophilic, obligately chemolithoautotrophic, hydrogen-oxidizer isolated from a Japanese solfataric field. Strain 3H-1 requires elemental sulfur for growth. We used PCR to amplify the 16S rRNA gene of strain 3H-1, and sequenced the amplification product directly. Phylogenetic analyses show strain 3H-1 is closely related to Aquifex pyrophilus and may be located in the deepest branch within the eubacterial phylogenetic tree. Sulfur-dependency of the ancestral eubacterium is also discussed.

Archaea↗
PubMed1994

Poststroke depression.

Sixty-eight patients with stroke were investigated to assess their mood state. Nearly half of them were found to be depressed; according to DSM-III-R, 6 of these were diagnosed as suffering from major depression and the rest from adjustment disorder with depressive mood. A significant relationship was found between mood state on the one hand, and daily living activities and Type A behavior pattern on the other.

Activities of Daily Living↗