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Biomedical subjects

D Mori

Publications and source records attributed to D Mori.

16 recordsLinked to original sources
PubMed2006

Spin gap in Tl2Ru2O7 and the possible formation of Haldane chains in three-dimensional crystals.

Dimensionality is one of the most important parameters of physical phenomena. Only two things determine the universality class of a phase transition: the dimensionality of a given system and the symmetry of the order parameter. In most cases, the dimensionality of a substance is predetermined by its crystal structure. Examples in which the effective dimensionality is reduced are quite rare. Here we show that the three-dimensional cubic system of Tl(2)Ru(2)O(7) most probably evolves into a one-dimensional spin-one Haldane system with a spin gap below 120 K, accompanied by anomalies in the structure, resistivity and susceptibility. We argue that these anomalies are due to an orbital ordering of Ru 4d electrons, with a strong coupling among three degrees of freedom: orbital, spin and lattice. Our work provides a unique example of the spontaneous formation of Haldane system with an insight into the intriguing interplay of different degrees of freedom.

Journal Article↗
PubMed2000

Membrane fusion proteins are required for oskar mRNA localization in the Drosophila egg chamber.

We used a genetic screen in Drosophila to identify mutations which disrupt the localization of oskar mRNA during oogenesis. Based on the hypothesis that some cytoskeletal components which are required during the mitotic divisions will also be required for oskar mRNA localization during oogenesis, we designed the following genetic screen. We screened for P-element insertions in genes which slow down the blastoderm mitotic divisions. A secondary genetic screen was to generate female germ-line clones of these potential cell division cycle genes and to identify those which cause the mislocalization of oskar mRNA. We identified mutations in ter94 which disrupt the localization of oskar mRNA to the posterior pole of the oocyte. Ter94 is a member of the CDC48p/VCP subfamily of AAA proteins which are involved in homotypic fusion of the endoplasmic reticulum during mitosis. Consistent with the function of the yeast ortholog, ter94-mutant egg chambers are defective in the assembly of the endoplasmic reticulum. We tested whether other membrane biosynthesis genes are required for localizing oskar mRNA during oogenesis. We found that ovaries that are mutant for syntaxin-1a, rop, and synaptotagmin are also defective in oskar mRNA localization during oogenesis. We suggest a pathway for the role of membrane assembly proteins on oskar mRNA localization.

Animals↗
PubMed2000

Studies on the genotype-phenotype relation in the hph-1 mouse mutant deficient in guanosine triphosphate (GTP) cyclohydrolase I activity.

The guanosine triphosphate (GTP) cyclohydrolase I (GTP-CHI) catalyses the rate-limiting step in the de novo synthesis of tetrahydrobiopterin, a cofactor of three aromatic amino acid hydroxylases, one of which is phenylalanine hydroxylase. The hph-1 mouse mutant deficient in GTP-CHI activity exhibits hyperphenylalaninemia which peculiarly disappears at 3 weeks of age, thus corresponding to the increase in liver GTP-CHI activity. The present gas chromatographic-mass spectrometric analysis of the phenylalanine and catecholamine metabolisms demonstrated the former metabolism to remain disturbed even in adult hph-1, which demonstrated a metabolic basis for sensitivity to the phenylalanine challenge in adult hph-1. A Northern blot analysis showed the hepatic GTP-CHI RNA expression in hph-1 at 2, 3 and 4 weeks of age to parallel the peculiar time course of the enzyme activity previously reported. No mutation was detected in either the coding region or the 5' flanking region (nt.-1 to -746) of the GTP-CHI gene of the hph-1. Further molecular genetic analyses are therefore required to elucidate the mechanism of the peculiar phenotype of hph-1.

Animals↗
PubMed1999

Relevance of ER to the Development of Endometrial Hyperplasia and Adenocarcinoma.

Estrogen has an important role in both the etiology and treatment of hormone-dependent endometrial cancers, although the mechanism remains elusive. To definethe role of estrogen-mediated signaling we investigated the biological significance of estrogen receptors (ER) in NIH3T3 cell transformation via the [ &sup12; Val ] K-Ras mutant. This mutant enhanced the steady state level and transcriptional activity of ER. In addition, overexpression of both wild type K-Ras and ER transformed NIH3T3 cells. Co-expression of the progesterone receptor (PR) with mutant K-Ras led to suppression of tumorigenicity and inhibition of ER activation. The antisense oligomers complementary to ER suppressed proliferation and transformed phenotypes of K12V cells. These observations support the importance of ER in Ras-mediated cell transformation. To address whether ER activation is also important in the development of human endometrial cancers, we investigated ER and PR expression levels in premalignant and malignant endometrial lesions. The results suggested the implication of ER abundance in endometrial hyperplasias, though modulation of PR expression by ER was retained. G1 adenocarcinoma also expressed higher levels of ER while PR modulation by ER was abrogated. These data implied the importance of ER activitiesin endometrial hyperplasia and G1 adenocarcinoma development.

Journal Article↗
PubMed1999

A novel follicle-cell-dependent dominant female sterile allele, StarKojak, alters receptor tyrosine kinase signaling in Drosophila.

We describe a new dominant allele, StarKojak, that alters receptor tyrosine kinase signaling in the follicle cells and in the eyes in Drosophila. We isolated StarKojak in a screen for follicle-cell-dependent dominant female sterile mutations. We show that StarKojak and revertants of StarKojak do not complement Star loss-of-function mutations. We propose that StarKojak is a novel type of allele of Star that has both dominant gain-of-function phenotypes early in development and dominant loss-of-function phenotypes later in development. Star encodes a putative transmembrane protein that has previously been shown to be a critical component of the epidermal growth factor receptor tyrosine kinase signaling pathway. Early in oogenesis, Star mRNA expression is higher in StarKojak egg chambers than in wild-type egg chambers, consistent with its gain-of-function phenotype. Later in oogenesis, Star mRNA expression is lower in StarKojak follicle cells than in wild-type follicle cells, consistent with its loss-of-function phenotype. By genetically analyzing StarKojak and its revertants, we present evidence that Star is involved in anterior-posterior axis formation both in the female germline cells and in the somatic follicle cells. We also demonstrate that at least part of the dominant female sterile phenotype of StarKojak is restricted to the posterior-pole follicle cells. We propose that Star functions by processing pro-Gurken to mature Gurken, which is thereby released in the region between the oocyte and the follicle cells and binds to the epidermal growth factor receptor in the follicle cells.

Alleles↗
PubMed1997

Frontal midline theta rhythm in young healthy adults.

In this study, we examined the relationship between the frontal midline (Fm) theta rhythm that appears when a healthy subject is engaged in mental tasks and the theta rhythm which appears in the frontal region of healthy subjects during light drowsiness. The samples for this study were obtained from 465 EEGs of healthy Japan Air Self Defense Force personnel. The 39 who had frontal theta rhythm during light drowsiness were selected to be included in the theta group. For the control group, 34 subjects were randomly selected from the remaining 426 without frontal theta rhythm. When these subjects were reexamined, the rate of appearance of the frontal midline theta rhythm which appears during light drowsiness was 87.2% in the theta group and 0% in the control group. The rate of appearance of the Fm theta was 94.9% in the theta group and 3.0% in the control group. The two types of frontal theta rhythms closely resembled each other in frequency (94.6%) and distribution (83.8%). Except for the results of the hypomania (Ma) scores, there was no remarkable difference between the two groups when the MMPI was administered. The results of our study suggest that there is a close correlation between the frontal theta rhythm that appears during light drowsiness and the Fm theta.

Adolescent↗
PubMed1995

[Outcome of schizophrenia--extended observation (more than 30 years) of 129 typical schizophrenic cases [III]].

We had already made a report on outcome of schizophrenia (1986). The patients, 129 typical schizophrenia, were continuously observed over 30 years in the Kawagoe Dojinkai Hospital. Recently, we again evaluated their prognoses according to the same criteria as adopted in the first report, and divided them into the following five groups. [symbol: see text]: completely remitted group (21 persons, 16.3%), [symbol: see text]: almost remitted cases now holding jobs (23 persons, 17.8%), [symbol: see text]: Slightly remitted group showing good adjustment at home or hospital (41 persons, 31.8%), [symbol: see text]: maladjusted cases always showing an unfavorable condition (25 persons, 19.4%), x : incurable cases (19 persons, 14.7%). 1) In the last 8 years, there were 30 persons (23.3% of the whole patients) who showed prognostic changes (10 persons improved, 20 persons worsen). While the second group ([symbol: see text]) has seen fewer persons (12 persons down) than previous study, the third group ([symbol: see text]) has seen more persons (9 persons up). Each three groups, that is, the first two groups ([symbol: see text] + [symbol: see text], 44 persons, 34.1%), the third group ([symbol: see text], 41 persons, 31.8%), and the forth and fifth groups ([symbol: see text] + x, 44 persons, 34.1%) accounted for a third of the whole patients. It is after 32 years on the average (extending from 21 to 50 years) from the onset of illness that they showed prognostic changes. 2) Generally speaking, catatonic patients had favorable prognoses, hebephrenic patients unfavorable ones, and paranoid patients medium ones. But 4 improved persons in the forth and fifth groups were all hebephrenic type. 3) 17 among the 30 persons who showed prognostic changes were unstable type. They took a wave-like course. 4) 27 of all the 129 patients were dead. 25 were dead from disease mentioned below. Malignancy (8 persons), Cerebral vascular disease, Pneumonia and Diabetes (3 persons), Heart-failure (2 persons), Ileus, Myocardial infarction, Hepato-cirrhosis, Gastric ulcer, Tuberculosis and Natural death (1 person). 2 persons committed suicide. 5) Outcome of 45 patients who discontinued our medical therapy became clear as follows. [symbol: see text] + [symbol: see text]: 18 persons (40.0%), [symbol: see text]: 9 persons (20.0%), [symbol: see text] + x : 18 persons (40.0%). A smaller percentage of the patients belongs to the third group ([symbol: see text]) than that of our patients who were continuously followed by us.

Adult↗
PubMed1987

"Eating lightly" and the self-presentation of femininity.

In Experiment 1, male and female subjects were given an opportunity to snack as they participated in a "get-acquainted study" with a same-sex or opposite-sex partner (confederate) whose social desirability was manipulated. Consistent with the hypothesis that women may eat less when motivated to present themselves in a feminine light, female subjects ate significantly less with a desirable male partner than in the remaining three conditions. In contrast, male subjects did not eat more (or less) with a desirable woman, although they did show an overall tendency to eat less with female (vs. male) partners. In Experiment 2, female subjects snacked as they got acquainted with a desirable male partner (confederate). Before this interaction, subjects received feedback indicating that they had either very masculine or very feminine interests. In addition, subjects believed either that their male partner was aware of their gender feedback or that he was unaware. Consistent with predictions derived from Schlenker's (1982) analytic-identity theory of social conduct, subjects in the partner-aware conditions ate less when they had received masculine (vs. feminine) feedback, whereas subjects in the partner-unaware conditions ate less when they had received feminine (vs. masculine) feedback. Implications for understanding eating disorders such as anorexia and bulimia are discussed.

Adult↗
PubMed1980

Effect of retraction procedures on the periodontium in humans.

On the basis of wound healing and gingival recession caused by the three procedures, the copper-band retraction method was the most satisfactory. This tentative conclusion is based on the following reasons: 1. Retraction methods must be evaluated relative to the impression procedure and fit of the restoration. The long-range effects of the marginal fit are probably the most important factor for enhancing periodontal health. 2. This study involved only healthy periodontia of adolescent patients. Different healing might be observed in tissues characterized by gingivitis or periodontitis. 3. A broader study involving a greater range of procedures and conditions is recommended to evaluate each retraction technique. 4. This study involved teeth which had an adequate zone of attached gingiva. More complicated healing and perhaps altered sequences might be observed if the procedures were performed on gingival margins of alveolar mucosa, thin gingival walls, or areas of root prominence and thin cortical bone.

Adolescent↗