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Biomedical subjects

T Tachi

Publications and source records attributed to T Tachi.

9 recordsLinked to original sources
PubMed2001

Heterodimer formation between the antimicrobial peptides magainin 2 and PGLa in lipid bilayers: a cross-linking study.

The antimicrobial peptides magainin 2 and PGLa, isolated from the skin of the African clawed frog Xenopus laevis, show marked synergism [Westerhoff, H. V., Zasloff, M., Rosner, J. L., Hendler, R. W., de Waal, A., Vaz Gomes, A., Jongsma, A. P. M., Riethorst, A., and Juretic, D. (1995) Eur. J. Biochem. 228, 257-264]. We suggested previously that these peptides form a potent heterodimer composed of either parallel or antiparallel helices in membranes [Matsuzaki, K., Mitani, Y., Akada, K., Murase, O., Yoneyama, S., Zasloff, M., and Miyajima, K. (1998) Biochemistry 37, 15144-15153]. To detect the putative heterodimer by chemical cross-linking, analogues of magainin 2 and PGLa with a Cys residue at either terminus were synthesized. These cross-linking experiments suggested that both peptides form a parallel heterodimer in membranes composed of phosphatidylglycerol/phosphatidylcholine but not in either buffer or a helix-promoting 2,2,2-trifluoroethanol/buffer mixture. The isolated parallel heterodimers exhibited an order of magnitude higher membrane permeabilization activity compared with the monomeric species, indicating that the observed synergism is due to heterodimer formation.

Amino Acid Sequence↗
PubMed2001

Effects of peptide dimerization on pore formation: Antiparallel disulfide-dimerized magainin 2 analogue.

To elucidate the effects of peptide dimerization on pore formation by magainin 2 (MG2), a covalently linked antiparallel dimer of the MG2 analogue [(F5Y, L6C, F16W, I20C-MG2)(2): II] was synthesized based on the dimer structure revealed by our NMR study. The interactions of the dimer with lipid bilayers were investigated by CD and fluorescence in comparison with a monomer analogue (F5Y, F16W-MG2: I). Similar to I, II was found to form a peptide-lipid supramolecular complex pore accompanied with lipid flip-flop and peptide translocation. The pore formed by II was characterized by a slightly larger pore diameter and a threefold longer lifetime than that of I, although the pore formation rate of the dimer was lower than that of the monomer. The coexistence of the dimer and the monomer exhibited slight but significant synergism in membrane permeabilization, which was maximal at a monomer/dimer ratio of 3. Therefore, we concluded that a pentameric pore composed of one pore-stabilizing dimer and three monomers maximized the overall leakage activity in keeping with our kinetic prediction.

Amino Acid Sequence↗
PubMed2001

Affective states associated with bingeing and purging behaviours in Japanese patients with bulimia nervosa.

This study investigated the relationship between binge-purge episodes and the affective state by analysing the changes in affective states during the binge-purge cycle. Thirty-seven Japanese patients with bulimia nervosa were surveyed for 22 types of affective states. Some negative affects were alleviated by bingeing or purging, while others were exacerbated by these behaviours. These findings suggest that one has to differentiate the temporal situations in the binge-purge cycle in considering the relationship between the affective states and binge-purge behaviours. The escape hypothesis and hopelessness hypothesis proposed by Beebe (1994) suggest some possible mechanisms. Binge and purge behaviours should be examined separately as defence functions to regulate negative moods and as acting out in response to intense negative affects.

Adult↗
PubMed1999

[Family environment in eating disorders: a study of the familiar factors influencing the onset and course of eating disorders].

OBJECTIVE: This study investigated the association of family environment and symptomatic characteristics in eating disorders. METHOD: The subjects studied were 180 eating disorder patients who sought treatment at Tokai University Hospital and whose diagnoses were made using the SCID (Structured Clinical Interview for DSM-III-R) modified for DSM-IV. The subjects consisted of 52 Anorexia Nervosa Restricting Type (AN/R), 40 Anorexia Nervosa Binge-Eating/Purging Type (AN/BP), 57 Bulimia Nervosa Purging Type (BN/P), 17 Bulimia Nervosa Nonpurging Type (BN/NP) and 14 Binge-Eating Disorder (BED). All subjects were given the Family Adaptability & Cohesion Evaluation Scales III (FACES-III). Seventy eight female college students were administered the FACES-III, as normal controls. RESULTS: On the cohesion (CO) dimensions of FACES-III, most AN/R perceived their families as significantly enmeshed (high CO), whereas most BN and BED perceived their families as disengaged (low CO). The families of AN/BP rated lower CO than AN/R, and higher CO than BN. On the adaptability dimension of FACES-III, most AN/BP and BED perceived their families as rigid, and most BN/P perceived their families either rigid or chaotic. DISCUSSION: 1) The family environment of eating disorder patients exist, on a continuum of cohesion, from AN/R (enmeshed), through AN/BP (intermediate cohesion) and BN (disengaged), to BED (most disengaged). It's suggested that there might be an association of enmeshed family environment and severity of restrict-eating. In addition, the disengaged family environment might have an association with the onset of binge-eating. 2) It's also suggested that the two extremes on the adaptability dimension, rigid and chaotic, were the characteristic features of the family environment, which might precipitate and maintain binge-eating and purging symptoms. 3) The two hypotheses were proposed with regard to the familiar contribution on the outcome of AN/R. (a) AN/R, whose family environment are enmeshed, would not develop bulimic symptoms in the future. (b) AN/R, whose family environment are disengaged, particularly with rigid or chaotic atmosphere, have high risks of developing bulimia later. 4) The author discussed that dividing AN/BP into the two categories: binge subtype and non-binge subtype, should be recommended in the future diagnostic classification of the eating disorders, on the basis of analyzing both groups' family environments. 5) Comparing the family environment of the Japanese BED and the western BED suggested that the Japanese BED might be more severe in psychopathology. The author discussed the comorbidity of BED and the Borderline Personality Disorder, as well as the social influence on the clinical features of BED.

Adult↗
PubMed1991

Couple therapy with parents whose youngest daughter had a psychotic episode: impairment of a child and marital conflict.

An 18-year-old girl developed a withdrawn state with suicidal ideas. The therapist gave 8 sessions of conjoint family therapy, with her parents and two sisters. In the course of conjoint therapy, she became psychotic and some structural features of the disturbed family system seemed to get more rigid. The therapist therefore, changed the therapeutic modality from conjoint therapy to couple therapy with her parents. During the sessions of couple therapy, the therapist tried to help her parents gain an understanding of his or her respective family of origin. The girl, as a result, got through the psychotic state and her condition stabilized. The author discussed the following points: 1) The girl's symptoms were understood to be the result of chronic tension between her parents, and disappeared when her parents became involved with their couple therapy. 2) Each parent transmitted many unresolved issues in the context of his or her original family to their nuclear family. 3) In couple therapy, when the marital conflict is so great, the couple tend to involve the therapist in triangulation. Therefore, it is very important for the therapist to keep himself in a position of distriangulation with the couple.

Adolescent↗
PubMed1984

[A case of malignant clear cell hidradenoma of the skin presumably arising from adenoma].

A left parietal skin tumor showing rapid enlargement in a 33-year-old woman was excised. The cut surface of the skin revealed a whitish tumor 4 cm in diameter associated with a cyst formation. Histologically, the whitish tumor was mucinous carcinoma in which large clear cells were conspicuous. Because nests of clear cell hidradenoma (CCH) were seen in the cyst wall, this carcinoma was diagnosed as malignant CCH presumably arising from a part of benign CCH. Malignant CCHs are thought to be malignant from their onset. Those proved to have developed from benign CCHs like the present case are extremely rare.

Adenoma↗