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Biomedical subjects

T Oki

Publications and source records attributed to T Oki.

At least 19 recordsLinked to original sources
PubMed1996

Relationship between sonographic endometrial thickness and progestin-induced withdrawal bleeding.

OBJECTIVE: To determine whether the response to the progestin challenge test can be predicted from the endometrial thickness measured sonographically. METHODS: Progestin challenge tests were performed on 44 women with secondary amenorrhea, each of whom also had her endometrial thickness measured by transvaginal ultrasonography and her serum estradiol (E2) levels determined. The relationships between the response to the challenge test, endometrial thickness, and serum E2 levels were studied, as well as whether the presence or absence of withdrawal bleeding could be predicted from the endometrial thickness and serum E2 levels. RESULTS: The endometrium was significantly thicker in 32 women who had withdrawal bleeding (10.3 +/-4.1 mm) than in the 12 who did not bleed (5.0 +/- 1.3 mm) (P < .001). The serum E2 level was also significantly higher in the positive group: 45.3 +/- 19.4 versus 18.6 +/- 8.0 pg/mL (P < .001). Endometrial thickness of 6.0 mm or more predicted the occurrence of withdrawal bleeding with an accuracy of 95.5%. Endometrial thickness was superior to the serum E2 level in predicting withdrawal bleeding. CONCLUSION: Progestin-induced withdrawal bleeding can be predicted from the endometrial thickness measured sonographically.

Adult↗
PubMed1996

Angelmicin B, a new inhibitor of oncogenic signal transduction, inhibits growth and induces myelomonocytic differentiation of human myeloid leukemia HL-60 cells.

Angelmicin B is a new microbial substance which inhibits src tyrosine kinase activity and oncogenic signal transduction. We investigated the effect of angelmicin B on the proliferation and differentiation of the HL-60 human myeloid leukemia cell line. Angelmicin B caused the dose-dependent inhibition of cell proliferation and induction of differentiation along the myelomonocytic pathway, as determined by morphological changes, nitroblue tetrazolium (NBT) reduction, and non-specific esterase and lysozyme activities at concentrations ranging from 0.1 to 0.5 microgram/ml. Also, it induced significantly the differentiation of mouse myeloid leukemia M1 cells. A similar concentration of angelmicin B inhibited the growth of the myeloid leukemia cell lines K562, HEL, KU812, ML-1, U937 and THP-1, but did not induce differentiation of these cells significantly. The differentiation of HL-60 cells was enhanced by combined treatment with angelmicin B and 1 alpha, 25-dihydroxyvitamin D3 (VD3), retinoic acid or tumor necrosis factor-alpha (TNF alpha). Angelmicin analogs (A1, A2, B, C and D) had almost equivalent effects on the differentiation of HL-60 cells, although angelmicins C and D inhibited src tyrosine kinase activity less than the other analogs. The effective concentrations of angelmicin B in src kinase inactivation was about 100-fold higher than those required for the growth inhibition and differentiation induction. These findings indicate that the differentiation-inducing activity of angelmicins is not associated with their src kinase-inhibiting activity, and may be associated with the modulation of other signal pathway(s).

Animals↗
PubMed1996

Changes in transmitral and pulmonary venous flow velocity patterns after cardioversion of atrial fibrillation.

To examine the recovery time of left atrial mechanical function after electrical cardioversion of atrial fibrillation, we recorded transmitral flow, pulmonary venous flow velocities, and interatrial septal motion during atrial systole within 24 hours (16 +/- 5 hours) and 10 days after cardioversion in 25 patients with atrial fibrillation, including 6 patients with hypertension, 4 with ischemic heart disease, 2 with alcoholic heart disease, 5 with dilated cardiomyopathy, and 8 with no evidence of underlying heart disease. With the exception of the five patients with dilated cardiomyopathy, the peak atrial systolic transmitral and pulmonary venous flow velocities, peak first systolic velocity of pulmonary venous flow, duration of both atrial systolic waves, and amplitude of the interatrial septal motion during atrial systole decreased markedly within 24 hours after cardioversion and increased 10 days after cardioversion. These results suggest that active atrial systolic and relaxant variables obtained from transmitral and pulmonary venous flow velocities may reflect left atrial mechanical function after cardioversion of atrial fibrillation.

Atrial Fibrillation↗
PubMed1995

Predisposing factors for severe mitral regurgitation in idiopathic mitral valve prolapse.

To elucidate predisposing factors for severe mitral regurgitation (MR) in idiopathic mitral valve prolapse (MVP), 124 MVP patients were classified into the following categories: 55 with isolated clicks (click group), 35 with a late-systolic murmur (late-SM group), and 34 with a holosystolic murmur (holo-SM group). Their clinical and echocardiographic findings were compared with those of 26 patients with spontaneous chordal rupture (rupture group). In 22 patients in the click group, 24 in the late-SM group, and 22 in the holo-SM group, follow-up studies were performed for a mean of 4.5 years (range 1 to 13.5). The mean age was youngest in the click group and oldest in the rupture group. The click and late-SM groups showed a female predominance, but the holo-SM and rupture groups showed a male predominance. There was no difference in the incidence of systemic hypertension among the 4 groups. Most patients in the click and late-SM groups had anterior leaflet prolapse. In the holo-SM and rupture groups, however, the incidence of posterior leaflet involvement was significantly increased. The incidence of thickened mitral valve increased in order of the click (8%), late-SM (21%), holo-SM (38%), and rupture (50%) groups. Six patients in the holo-SM group developed chordal rupture with severe MR during the follow-up period. In the click and late-SM groups, however, there were no complications and no development into a holo-SM. Thus, aging, male sex, posterior leaflet prolapse, thickened mitral valve, and holo-SM were found to be important predisposing factors for severe MR in idiopathic MVP.

Adult↗
PubMed1995

High-resolution solution structure of siamycin II: novel amphipathic character of a 21-residue peptide that inhibits HIV fusion.

The 21-amino acid peptides siamycin II (BMY-29303) and siamycin I (BMY-29304), derived from Streptomyces strains AA3891 and AA6532, respectively, have been found to inhibit HIV-1 fusion and viral replication in cell culture. The primary sequence of siamycin II is CLGIGSCNDFAGCGYAIVCFW. Siamycin I differs by only one amino acid; it has a valine residue at position 4. In both peptides, disulfide bonds link Cys1 with Cys13 and Cys7 with Cys19, and the side chain of Asp9 forms an amide bond with the N-terminus. Siamycin II, when dissolved in a 50:50 mixture of DMSO and H2O, yields NOESY spectra with exceptional numbers of cross peaks for a peptide of this size. We have used 335 NOE distance constraints and 13 dihedral angle constraints to generate an ensemble of 30 siamycin II structures; these have average backbone atom and all heavy atom rmsd values to the mean coordinates of 0.24 and 0.52 A, respectively. The peptide displays an unusual wedge-shaped structure, with one face being predominantly hydrophobic and the other being predominantly hydrophilic. Chemical shift and NOE data show that the siamycin I structure is essentially identical to siamycin II. These peptides may act by preventing oligomerization of the HIV transmembrane glycoprotein gp41, or by interfering with interactions between gp41 and the envelope glycoprotein gp120, the cell membrane or membrane-bound proteins [Frèchet, D. et al. (1994) Biochemistry, 33, 42-50]. The amphipathic nature of siamycin II and siamycin I suggests that a polar (or apolar) site on the target protein may be masked by the apolar (or polar) face of the peptide upon peptide/protein complexation.

Amino Acid Sequence↗
PubMed1995

Body fat distribution in women with polycystic ovary syndrome.

OBJECTIVE: To investigate body fat distribution in women with polycystic ovary syndrome (PCOS). METHODS: Body weight, body mass index (BMI), and six indices of body fat measured by dual-energy x-ray absorptiometry were compared in 40 women with PCOS and 97 age-matched controls. The possible correlations between the body fat characteristics and serum androgen levels were evaluated in the 40 PCOS women. Body fat distribution was classified into upper- (N = 24) and lower-half body type (N = 16), and androgen levels and the incidence of hirsutism were compared in the two types. RESULTS: The BMI, body fat ratio, upper-half body fat ratio, and upper-half/lower-half body fat ratio were significantly higher in PCOS women than in controls. After adjustment for age, height, and body weight, the upper-half/lower-half body fat ratio was still significant (P < .001). The PCOS subjects exhibited a significant positive correlation between the upper-half/lower-half body fat ratio and dehydroepiandrosterone-sulfate (DHEA-S) levels (r = 0.607, P < .01) as well as testosterone levels (r = 0.585, P < .05). Dehydroepiandrosterone-sulfate and testosterone levels were significantly higher in those with the upper-half body type than in those with the lower-half body type (P < .001). After adjustment for confounding variables, only DHEA-S was still significantly higher in this body type (P < .05). CONCLUSION: Serum DHEA-S levels seem to be associated with upper-half body fat distribution in women with PCOS, irrespective of body weight.

Adipose Tissue↗
PubMed1995

A maternal risk factor for mother-to-child HTLV-I transmission: viral antigen-producing capacities in culture of peripheral blood and breast milk cells.

We examined the relationship between productivity of HTLV-I antigen-positive cells in cultured peripheral blood mononuclear cells (PBMC) and breast milk mononuclear cells (BMMC) and the incidence of mother-to-child transmission of HTLV-I. Among 61 cases of HTLV-I carrier mothers, 17 cases were revealed to produce large numbers of HTLV-I antigen-positive cells (high HTLV-I antigen-producing mothers) whose positive rate was 9.6% in PBMC and 10.2% in BMMC, while the remaining 44 cases produced small numbers of HTLV-I antigen-positive cells (low HTLV-I antigen-producing mothers) whose positive rate was 0.3% in PBMC and 0.5% in BMMC. The HTLV-I transmission rate among children born to the high HTLV-I antigen-producing mothers was 37.5% (6/16 children from 11 mothers), while that of the low HTLV-I antigen-producing mothers was 3.2% (1/31 children from 20 mothers). The transmission rate of HTLV-I was significantly different between high and low HTLV-I antigen-producing mothers (P < 0.05). However, there was no positive relationship between anti-HTLV-I antibody titers and productivity of HTLV-I antigen-positive cells (P = 0.11). These results suggested that mother-to-child transmission of HTLV-I might be influenced by a maternally determined factor to produce HTLV-I antigen-positive cells in PBMC and BMMC of HTLV-I carrier mothers.

Adult↗
PubMed1995

Changes of bone mineral density in pregnant and postpartum women.

OBJECTIVE: To explore the effects of pregnancy and postpartal lactation on bone mineral density (BMD). METHODS: In this study, the BMD of 22 pregnant women in a longitudinal study, and of 75 pregnant and 111 puerperant women in a cross-sectional study was estimated at the distal radius of the forearm by dual energy X-ray absorptiometry. BMD was measured on 8 separate occasions from the first trimester of pregnancy to 24 months' postpartum. RESULTS: In none of 22 pregnant women was there any noticeable change in BMD during pregnancy. Whereas no significant change in BMD occurred during the 12-month postpartum period in 11 non-lactating women, 11 women who breastfed had a significant decrease in BMD at 1, 3, and 6 months' postpartum, with all of them showing a further decrease in BMD at 12 months' postpartum. The BMD of the radius was significantly lower in the breast-feeders than in the formula-feeders at all postpartal times of evaluation except at 24 months' postpartum. CONCLUSION: It can be recommended that lactating women receive appropriate treatments for saving BMD during lactation.

Adult↗
PubMed1995

Screening and production of arylsulfatases for target therapy with etoposide 4'-sulfate, an antitumor prodrug.

Two arylsulfatase-producing streptomycetes that desulfated etoposide 4'-sulfate were isolated from soil samples. Taxonomical study identified one soil isolate as Streptomyces griseorubiginosus S980-14 (Es-1 arylsulfatase producer), while the other was considered new and tentatively designated Streptomyces sp. T109-3 (Es-2 arylsulfatase producer). Both strains produced extracellular arylsulfatase activities, provided that cultivation media were prepared with distilled water. Unlike the two known types of arylsulfatases, which had significant activity on p-nitrophenyl sulfate but none on etoposide 4'-sulfate, the crude streptomycete arylsulfatases efficiently desulfated etoposide 4'-sulfate and p-nitrophenyl sulfate, which supports the establishment of a new type of arylsulfatases.

Antineoplastic Agents↗
PubMed1995

Arylsulfatase from Streptomyces griseorubiginosus S980-14.

A new arylsulfatase designated Es-1, which desulfated etoposide 4'-sulfate and p-nitrophenyl sulfate, was isolated from Streptomyces griseorubiginosus S980-14 and purified to protein homogeneity by ammonium sulfate fractionation, ion exchange column chromatography, and chromatofocusing. The enzyme was active in monomeric form with an approximate molecular weight of 45,000, had a pI value of 4.95, and required calcium for full activity. At an optimum reaction pH of 8.5, iodoacetate, mercurous chloride, and EDTA severely inhibited the activity of Es-1 arylsulfatase.

Arylsulfatases↗
PubMed1995

A new type of Streptomycete arylsulfatase with high affinity to the sulfuryl moiety of the substrate.

Streptomyces sp. T109-3 arylsulfatase (Es-2), which desulfated p-nitrophenyl sulfate as well as etoposide 4'-sulfate, was purified to protein homogeneity by sulfated cellulose affinity and DEAE-cellulose column chromatographies. Es-2 required calcium for enzyme activity and was severely inhibited by SH and chelating reagents. Comparative characterization showed that, although distinct in recognition of the binding moiety of substrate, Es-1 (Streptomyces griseorubiginosus S980-14 arylsulfatase) and Es-2 shared high desulfating activity on etoposide 4'-sulfate and many other common enzymological characteristics, which suggested they would be acceptable as the enzyme component of antitumor antibody-enzyme conjugates for target chemotherapy.

Amino Acid Sequence↗
PubMed1995

Evaluation of left ventricular diastolic hemodynamics from the left ventricular inflow and pulmonary venous flow velocities in hypertrophic cardiomyopathy.

We evaluated the characteristics of left ventricular diastolic hemodynamics in hypertrophic cardiomyopathy (HCM) by measuring left ventricular inflow (LVIF) and pulmonary venous flow (PVF) velocities in 62 patients with asymmetric septal hypertrophy and 34 normal controls. The patients were divided into four groups according to the LVIF pattern and left ventricular end-diastolic pressure (LVEDP): 1) the pseudonormalization group; 13 patients with the ratio of peak atrial systolic (A) to early diastolic (E) LVIF velocity (A/E) < or = 1 and LVEDP > or = 15 mm Hg, 2) the normal pattern group; 10 patients with the A/E < or = 1 and LVEDP < 15 mm Hg, 3) the relaxation failure group; 25 patients with the A/E > 1, and 4) the mid-diastolic wave group; 14 patients with a mid-diastolic wave. The peak early diastolic LVIF velocities in the pseudonormalization, relaxation failure and mid-diastolic wave groups were significantly smaller than in the control group. The deceleration time from the peak of the E wave and the isovolumic relaxation time were significantly prolonged in the relaxation failure and mid-diastolic wave groups. The peak diastolic PVF velocity in the relaxation failure and mid-diastolic wave groups was significantly decreased, and was significantly increased in the pseudonormalization group. The peak atrial systolic PVF velocity was significantly increased in all patients with HCM, particularly in the pseudonormalization group. LVEDP was the highest in the pseudonormalization group, followed by the mid-diastolic wave, relaxation failure and normal pattern groups, in that order. In conclusion, combined analysis of the LVIF and PVF provides useful information regarding various abnormalities of left ventricular diastolic hemodynamics in patients with HCM.

Adult↗
PubMed1995

The first heart sound in atrial septal defect with reference to atrioventricular valve motion and hemodynamics.

To clarify the characteristics of the first heart sound in atrial septal defect (ASD) and its pathophysiological basis, 17 patients with ASD associated with incomplete right bundle branch block (IRBBB) and 7 with isolated IRBBB were studied using phonoechocardiography and Doppler echocardiography. Fifteen of the 17 ASD patients also were studied following surgical closure of the defect. Indices were compared among the preoperative ASD, postoperative ASD, and IRBBB groups including: P-Q intervals, loudness of the mitral and tricuspid component of the first heart sound (IM, IT), end-diastolic closing excursions of the mitral and tricuspid valves (Mx, Tx), and mitral and tricuspid inflow velocities during early diastole and atrial contraction. There were no significant differences in the P-Q intervals among these 3 groups. IM was attenuated, and IT was accentuated in ASD compared with IRBBB. Postoperatively, IM was augmented in all but 1 patient and IT was attenuated in all patients. Mx was significantly smaller, and Tx was significantly larger in ASD than in IRBBB. Postoperatively, Mx was significantly increased and Tx was significantly reduced; the maximal mitral inflow velocity during atrial contraction was increased while the maximal tricuspid inflow velocity was significantly reduced. Thus, the first heart sound in ASD is characterized by an attenuated mitral component and an accentuated tricuspid component. Hemodynamic alterations and consequent changes in closing energies of the atrioventricular valves probably account for these features.

Adolescent↗