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Biomedical subjects

T Hata

Publications and source records attributed to T Hata.

At least 127 records · Page 7Linked to original sources
PubMed1999

Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes.

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17beta-estradiol (10-30 microM) significantly prolonged the action potential duration (APD) at 20% (APD(20)) and 90% repolarization (APD(90)) at stimulation rates of 0. 1-2.0 Hz. In the presence of 30 microM 17beta-estradiol, APD(20) and APD(90) at 0.1 Hz were prolonged by 46.2 +/- 17.1 and 63.4 +/- 11.7% of the control (n = 5), respectively. In the presence of 30 microM 17beta-estradiol the peak inward Ca(2+) current (I(CaL)) was decreased to 80.1 +/- 2.5% of the control (n = 4) without a shift in its voltage dependence. Application of 30 microM 17beta-estradiol decreased the rapidly activating component of the delayed outward K(+) current (I(Kr)) to 63.4 +/- 8% and the slowly activating component (I(Ks)) to 65.8 +/- 8.7% with respect to the control; the inward rectifier K(+) current was barely affected. The results suggest that 17beta-estradiol prolonged APD mainly by inhibiting the I(K) components I(Kr) and I(Ks).

Action Potentials↗
PubMed1999

Clinical application of intrauterine sonography with high-frequency, real-time miniature transducer in gynecologic disorders. Preliminary report.

Our purpose was to determine whether intrauterine sonography with high-frequency, real-time miniature transducer (20 MHz) is useful for the diagnosis of gynecologic disorders. The study consisted of 37 women: 8 normal volunteers, 2 with molar pregnancy, 4 fibromyoma, 4 endometrial polyp, 1 intrauterine adhesion, 1 septate uterus, 5 atypical hyperplasia, 8 endometrial cancer, and 4 with cervical cancer. Comparison of diagnostic efficacy for gynecologic disorders between transvaginal and intrauterine sonography was made. The probe was easily introduced into the endometrial cavity in all patients. No notable complications were encountered. In subjects with a normal uterus, higher resolution for endometrial texture was obtained with intrauterine sonography than with transvaginal scanning. In patients with molar pregnancy, typical vesicular echoes were clearly identified. In patients with fibromyoma, myoma nodules were not clearly visualized because of poor attenuation of ultrasound. In subjects with endometrial polyp, intrauterine adhesion, and septate uterus, intrauterine lesions were clearly identified. In patients with atypical hyperplasia, high echogenicity of the endometrium was characterized. Myometrial invasion of the endometrial cancer was estimated correctly in 6 of 8 patients (75%). Intrauterine sonography could clearly detect early cervical invasion of the cervical cancer in all 4 patients, but transvaginal sonography could not do it. Intrauterine sonography with a high-frequency, real-time miniature transducer might be a useful diagnostic modality in gynecologic disorders, especially in the evaluation of early cervical cancer, endometrial cancer, and possibly in infertility practice.

Adult↗
PubMed1999

Detection of small-for-gestational-age infants with poor perinatal outcomes using individualized growth assessment.

OBJECTIVE: Our objective was to evaluate individualized growth assessment using the Rossavik growth model for detection of small-for-gestational-age (SGA) infants with a poor perinatal outcome. METHODS: Rossavik growth models derived from second-trimester ultrasound measurements were used to predict birth characteristics of 47 singleton SGA infants. Individual fetal growth curve standards for head and abdominal circumference, and weight were determined from the data of two scans obtained before 25 weeks' menstrual age and separated by an interval of at least 5 weeks. Comparisons between actual and predicted birth characteristics were expressed by the Growth Potential Realization Index (GPRI) and Neonatal Growth Assessment Score (NGAS). The proportions of perinatal outcomes [mechanical delivery, low Apgar score, abnormal fetal heart rate (FHR) patterns, neonatal acidosis, meconium staining of amniotic fluid, neonatal intensive care unit (NICU) admission and maternal complications] were compared between SGA infants with normal NGAS and those with abnormal NGAS. RESULTS: Of the 47 fetuses studied, 27 had normal growth outcomes at birth and 20 showed evidence of intrauterine growth restriction, based on NGAS. There were significant increases in mechanical deliveries, abnormal FHR patterns and meconium staining of amniotic fluid in cases of growth-restricted neonates, determined using the NGAS classification, when compared with events related to normally grown infants. However, there were no significant differences in low Apgar score, neonatal acidosis, NICU admission and maternal complications between the 2 groups. CONCLUSION: Individualized growth assessment should be useful for detection of SGA infants with poor perinatal outcomes.

Abdomen↗
PubMed1999

Maternal circulating nitrite levels are decreased in both normal normotensive pregnancies and pregnancies with preeclampsia.

OBJECTIVE: To evaluate whether maternal nitric oxide synthesis in pregnancies with preeclampsia is different from that in normal normotensive pregnancies. MATERIALS: Maternal circulating combined nitrate and nitrite levels or nitrite level were compared between 10 normotensive nonpregnant women, 30 normotensive pregnant women (10 first-trimester, 10 second-trimester, and 10 third-trimester pregnancies), 20 normotensive postpartum women (10 at 1 week after delivery, and 10 at 4 weeks after delivery), and 13 preeclamptic women (32 to 40 weeks' gestation). End-products of nitric oxide synthesis were measured from maternal venous blood samples using a fluorometric assay. RESULTS: Maternal circulating nitrite levels in nonpregnant women (1.13 +/- 0.22 microM) were significantly higher than those in the first-trimester pregnant women (0.68 +/- 0.13 microM), second-trimester pregnant women (0.65 +/- 0.13 microM), third-trimester pregnant women (0.48 +/- 0.17 microM), first puerperal week women (0.36 +/- 0.16 microM), and fourth puerperal week women (0.67 +/- 0.17 microM), respectively (p < 0.05). Maternal circulating nitrite level was decreased with advancing gestation, still remained low just after delivery, and was increased 4 weeks later. There was no significant difference in maternal circulating nitrite level between preeclamptic women (0.40 +/- 0.17 microM) and third-trimester pregnant women (0.48 +/- 0.17 microM). However, there were no significant differences in maternal circulating combined nitrate and nitrite levels among the groups. CONCLUSION: These results suggest that the maternal nitric oxide synthesis is not changed in normal normotensive pregnancies and pregnancies with preeclampsia. However, plasma nitrite level, which has stronger spasmolytic activity than the activity of the nitrate, was decreased in both normal normotensive pregnancies and pregnancies with preeclampsia.

Adult↗
PubMed1999

Intrauterine sonographic visualization of embryonic genital tubercle.

OBJECTIVE: To visualize embryonic genital tubercle using intrauterine sonography with a 20-MHz flexible catheter-based high-resolution real-time miniature transducer in early first-trimester pregnancy. DESIGN: Randomized prospective study. METHODS: A total of 39 women about to undergo therapeutic abortion from 7 to 10 weeks' gestational age were studied with specially developed catheter-based high-resolution real-time miniature (2.4 mm in outer diameter) ultrasound transducer (20 MHz). Before the intrauterine sonographic procedure was performed, transvaginal sonographic assessment of the embryo was conducted. The percentage of embryonic genital tubercle (or phallus) visualized at each gestational age using intrauterine and transvaginal sonography is presented. RESULTS: The genital tubercle could not be identified at 7 weeks of gestation with intrauterine sonography. The genital tubercle was visualized in 30% of embryos at 8 weeks' gestation, and in 100% of embryos at 9 and 10 weeks. The genital tubercle was situated somewhat cranially to the sacral prominence at this gestational age. The genital tubercle could not be depicted with transvaginal sonography between 7 and 10 weeks of gestation. CONCLUSIONS: Intrauterine sonography provides a novel means for visualization of genital tubercle of the embryo. These results suggest that intrauterine sonography can become an important modality in future embryological research and in detection of embryonic developmental disorders in the early first-trimester pregnancy.

Catheterization↗
PubMed1999

Three-dimensional sonographic features of Hydrops fetalis.

OBJECTIVE: To describe three-dimensional (3-D) sonographic features of hydrops fetalis. METHODS: A total of 6 cases with hydrops fetalis from 15 to 32 weeks of gestation were studied with transabdominal 3-D sonography (3.5 MHz). RESULTS: Before around 20 weeks of gestation, the skin becomes a transparent-like structure, so internal organs can be clearly identified. After 25 weeks, skin edema, pleural effusion, and ascites were well depicted. In the case with pleural effusion, hypoplastic lungs were clearly recognized. CONCLUSION: These results suggest that 3-D sonography provides a novel means of visualizing hydrops fetalis in utero.

Ascites↗
PubMed1999

A new member of the GP138 multigene family implicated in cell interactions in Dictyostelium discoideum.

The cellular slime mold Dictyostelium discoideum reproduces sexually under submerged and dark conditions. Its mating system is polymorphic and particularly interesting with respect to mechanisms of cell recognition. The cell-surface glycoprotein gp138 has been implicated in sexual cell interactions, as it was identified as a target molecule for the antibodies that block sexual cell fusion in D. discoideum. Two mutually homologous genes, GP138A and GP138B, have been cloned, but gene disruption experiments to clarify their functional relationships suggested that there is at least one more gene for gp138. Further protein analysis including peptide mapping also revealed that gp138 exists as three isoforms, DdFRP1, DdFRP2, and DdFRP3. GP138A encodes DdFRP2 and GP138B, DdFRP3, and the presence of a third gp138 gene encoding DdFRP1 was suggested. Here, we isolated and characterized a third GP138 gene, GP138C. Although the deduced amino acid sequences of GP138C matched completely with those of peptide fragments of DdFRP1 in the N-terminal half, the rest did not give complete matches. Overexpression of GP138C caused an increase in the intensity of DdFRP1, but disruption of this gene did not diminish DdFRP1. Our results indicate that GP138C encodes a protein very similar to but distinct from DdFRP1. The GP138 multigene family is thus composed of more members than previously expected, and their functional relationships are of special interest.

Amino Acid Sequence↗
PubMed1999

Effect of long-term exercise training on regional myocardial perfusion changes in patients with coronary artery disease.

The cardiac rehabilitation of patients with coronary artery disease (CAD) promotes exercise tolerance, improves left ventricular function, and decreases the heart rate and systolic blood pressure at the same load intensity. Several studies have shown that cardiac rehabilitation improves myocardial perfusion in CAD patients. However, the long-term (> or = 1 year) effect of cardiac rehabilitation on myocardial perfusion is still controversial. The effect of long-term exercise training on myocardial perfusion in CAD patients was assessed using thallium-201 (201Tl) exercise studies at a baseline (4 months after the onset of CAD) and at a 1-year or more follow-up in 58 patients with stable CAD. The subjects had been divided into a training group (n=35) participating in supervised exercise 2 times per week for the follow-up period, and the control group (n=23). There was an improvement in the myocardial perfusion on stress 201Tl scintigraphy in 20 of the 35 (57.1%) trained patients and in 3 of the 23 (13.0%) of the control patients (p<0.001). The number of 201Tl stress myocardial perfusion defect segments was significantly decreased after the cardiac rehabilitation training (231 to 153 segments), but showed no change in the control group (158 to 156 segments) (p<0.01). In spite of no significant differences in the number of involved coronary arteries, it improved (12/17 patients: 70.6%) more in the patients who had trained for more than 2 years compared to the patients who had trained for less than 2 years. The exercise tolerance increased in 25 of the 35 training group patients (71.4%), and in only 3 of the 23 control group patients (13.0%). The peak double products increased from 20,131+/-6,010 to 28,370+/-5,600 (p<0.01) in the training group, and showed no change in the control group (20,567+/-5,112 to 20,964+/-7,728 (NS)). The results indicated that the long-term physical training increased exercise tolerance and the double products of CAD patients. In addition, the training resulted in improved cardiac perfusion as evidenced by 201Tl scintigraphy. The findings suggest that exercise training is an advisable and effective treatment for patients with CAD.

Aged↗
PubMed1999

Depressive state with anxiety in repeated cold-stressed mice in forced swimming tests.

The effects of various types of stress and drugs were studied to assess mouse performance in forced swimming tests, following characterization of SART (specific alternation of rhythm in environmental temperature) stress. Immobility time in the test decreased in mice subjected to SART, acute cold and restraint stress. No change was noted due to chronic cold stress or repeated fasting. The shortened time did not recover even 24 hr after the end of SART and chronic restraint stress. The time in SART-stressed mice finally recovered at 5-7 days. Shortening of immobility time in SART-stressed mice was inhibited by diazepam and repeated imipramine but not by lithium carbonate. In chronic restraint-stressed mice, this time was inhibited by repeated lithium carbonate but not diazepam or imipramine. SART stress would thus appear related to anxiety and depression and may be useful for detecting new types of antidepressants.

Animals↗
PubMed1999

HUB1 is an autoantigen frequently eliciting humoral immune response in patients with adult T cell leukemia.

The immunological screening of a cDNA phage expression library prepared from an adult T cell leukemia (ATL) cell line, ST1, was performed with IgG class antibodies in the serum of an ATL patient by the SEREX method to analyze the repertoire of antigen molecules in ATL. Ten different cDNAs, 7 previously reported and 3 newly identified, were isolated. One of the identified cDNAs was homologous to the recently reported gene, HTLV-I U5RE binding protein 1 (HUB1) encoding a protein binding to a possible repressor element of the long terminal repeat of the human T lymphotropic virus type I (HTLV-I). The obtained cDNA was expressed as a fusion protein with glutathione S-transferase. HUB1 protein was prepared by subsequent treatment of the fusion protein with thrombin. Reactivity of IgG serum samples from ATL patients, asymptomatic HTLV-I carriers and normal donors against the purified protein was examined by Western blot analysis. Twenty-one out of 30 samples (70.0%) from ATL patients, 10/24 samples (41.7%) from HTLV-I carriers and 9/24 samples (37.5%) from healthy donors showed positive reactivity, indicating the autoantigenicity of HUB1. The development of ATL may be related to higher production of antibodies against HUB1.

Adult↗
PubMed1999

The disposition of 14C-labeled tacrolimus after intravenous and oral administration in healthy human subjects.

Tacrolimus is a macrolide lactone with potent immunosuppressive properties. It has been shown in clinical studies to prevent allograft rejection. The pharmacokinetics of tacrolimus in healthy subjects and transplant patients has been described in earlier studies using immunoassay methods; however, detailed information on the absorption, distribution, metabolism, and excretion of tacrolimus using a radiolabeled drug is lacking. The objective of the present study was to characterize the disposition of tacrolimus after single i.v. (0.01 mg/kg) and oral (0.05 mg/kg) administration of 14C-labeled drug in six healthy subjects. Tacrolimus was absorbed rapidly after oral dosing with a mean Cmax and Tmax of 42 ng/ml and 1 h, respectively. The oral bioavailability was about 20%. After i.v. and oral dosing, most of the administered dose was recovered in feces, suggesting that bile is the principal route of elimination. Urinary excretion accounted for less than 3% of total administered dose. In systemic circulation, unchanged parent compound accounted for nearly all the radioactivity; however, less than 0.5% of unchanged drug was detectable in feces and urine. The excretion of the metabolites was formation-rate-limited. The mean total body clearance at 37.5 ml/min was equivalent to about 3% of the liver blood flow. Renal clearance was less than 1% of the total body clearance. The mean elimination half-life was 44 h.

Administration, Oral↗
PubMed1999

[New screening method for coagulation abnormality including AT III deficiency during CABG].

In our institute, 1 ml of heparin is administered to the patients undergoing CABG before dissection and mobilization of the internal thoracic arteries (ITAs) and/or right gastroepiploic artery (GEA) to prevent possible thrombosis or coagulation tendency. Two patients with AT III deficiency underwent CABG and one of them died. The aim of this study is to know whether ACT check before and after administration of 1 ml of heparin is useful as a screening test of coagulation abnormalities including AT III deficiency. One hundred patients (84 males and 16 females) undergoing CABG were studied. Age ranged from 41 to 79 years (mean 64.8 +/- 8.0 years). One ml of heparin was administered to all the patients before ITAs and/or GEA were dissected and mobilized. ACT was doubly checked before (control ACT: c-ACT) and after (heparinized ACT: h-ACT) administration of heparin. ACT extension was defined as follows: ACT extension = (c-ACT)-(h-ACT). Mean c-ACT was 124 +/- 12 sec., h-ACT 188 +/- 26 sec. and ACT extension 64 +/- 24 sec. There were only 3 cases which ACT extension were less than 30 sec.: two of them were combined with AT III deficiency and the other was due to insufficient administration of heparin. In conclusion, examination of ACT after 1 ml administration of heparin is new, simple and convenient screening method for coagulation abnormalities including AT III deficiency during CABG.

Adult↗
PubMed1999

[Clinical study of emergency coronary artery bypass surgery].

Between January, 1996 and December, 1998, 29 patients were undergone emergency coronary artery bypass grafting (CABG) in our institute. Age ranged 34 to 85 years (mean 65 +/- 11 years, male:female = 25:4). Of 29 emergency cases, 3 were hospital death. Hospital mortality rate was 10.7%, which was significantly higher than the hospital mortality of elective CABG (1.4%) during the same period. The necessity of IABP before CABG was 72% in emergency cases (elective surgery: 0%). Thus the use rate of arterial grafts were 86.2% in emergency cases (elective surgery: 100%), the patency of the arterial grafts were 100%. It is important to make stable condition of the patients before the operation, and therefore it is important to make contact closely with the cardiologists for making stable condition and for lowering the operative mortality. And, we should use arterial grafts for the long term result as much as possible if it is an urgent operation.

Adult↗
PubMed1999

[The anesthetic management of a patient with a congenital mediastinal cyst undergoing video-assisted thoracoscopic surgery (VATS)].

We recently conducted video-assisted thoracoscopic surgery (VATS) on an 8-day-old boy in whom a congenital mediastinal cyst had caused obstruction of the left main bronchus. After the surgery, the cyst recurred and caused reobstruction of the airway. When he was 51-day-old, we conducted VATS again. We could not perform cystectomy by VATS because the left lung was inflated, and we conducted cystectomy by thoracotomy.

Airway Obstruction↗
PubMed1999

High dose rate microselectron mould ratiotherapy of a widespread superficial oral cancer.

Treatment of a case of widespread superficial oral squamous cell carcinoma with external beam irradiation, followed by high dose rate Microselectron mould radiotherapy, is reported. The tumor disappeared macroscopically after treatment, but there was infield recurrence in the buccogingival sulcus where the radiation dose might have been inadequate. Apart from some radiation mucositis within the treated area, edema and a superficial ulcer were observed in the tongue. These were considered to be due to radiation overdose. Although there is room for improvement, this mode of treatment has something to offer patients with hard-to-cure cancer.

Aged↗
PubMed1998

Motor and learning dysfunction during postnatal development in mice defective in dopamine neuronal transmission.

Mice lacking expression of tyrosine hydroxylase (TH), the first and rate-limiting enzyme of the catecholamine biosynthetic pathway, in dopaminergic neuronal cell types were generated by a transgenic rescue approach to clarify the role of dopamine signaling during postnatal development. Introduction of the TH transgene directed by the dopamine beta-hydroxylase gene promoter into TH knockout mice restored noradrenaline and adrenaline synthesis, preventing perinatal lethality and cardiac dysfunction in the knockout mice. Lack of TH expression in the cells that normally express the dopaminergic phenotype resulted in a marked reduction of dopamine accumulation in the tissues, which led to multiple behavioral abnormalities at the juvenile stage. These abnormalities were characterized by a reduction in spontaneous locomotor activity, blockade of methamphetamine-induced hyperactivity, cataleptic behavior, and defects in active avoidance learning. In contrast, development of the pituitary gland as well as production and secretion of the pituitary peptide hormones dependent on hypothalamic dopaminergic control were normally maintained, despite defective dopamine synthesis. These results demonstrate that dopamine neurotransmission is essential for controlling spontaneous and voluntary movement and associative learning during postnatal development through the nigrostriatal and mesocorticolimbic pathways.

Animals↗