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Biomedical subjects

M Higashi

Publications and source records attributed to M Higashi.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Optimization of pulse sequences for MR cholangiopancreatography with FASE].

Various types of pulse sequences for MR cholangiopancreatography (MRCP) have been developed in the past ten years. FASE (fast advanced spin echo) is one of the single-shot fast spin-echo sequences developed by Toshiba. By using this sequence, 2D single slice, 2D multiple slice and 3D methods can be provided. We routinely employ 2D single slice and 3D methods. The merit of 2D single slice method is conveniently obtained projection imaging within short data acquisition time. On the other hand, 3D method can yield detailed evaluation of various anatomical structures and abnormalities by using thin-slice source images. O2-inhalation study is especially recommended in case of 3D method. With the proper knowledge of sequence characteristics, MRCP using FASE can provide valuable informations of pancreatico-biliary diseases.

Biliary Tract↗
PubMed1998

[Elimination of artifacts in MRCP: technical consideration].

Artifacts of MR cholangiopancreatography (MRCP) include fluid-filled gastrointestinal tracts, respiratory motion artifacts, spasm of Oddi's sphincter, vascular compression of bile ducts, overlapping of various anatomical structures and bright signal of surrounding fatty tissue. In this article, various technical considerations to eliminate these artifacts were described for the better imaging analysis of MRCP. The use of high-concentration ferric ammonium citrate (Ferriseltz) is recommended to reduce bright signal of fluid-filled gastrointestinal tracts. In case of long breathhold sequences, O2-inhalation study is useful to eliminate respiratory motion artifacts. Careful attention should be paid to the spasm of Oddi's sphincter and the vascular compression of bile ducts to avoid erroneous interpretation of MRCP findings.

Arteries↗
PubMed1997

Effects of ginsenosides on maze performance and brain choline acetyltransferase activity in scopolamine-treated young rats and aged rats.

In young adult rats with scopolamine-induced cognitive impairment, choline acetyltransferase activity was increased in the medial septum, but not in the diagonal band, caudate and hippocampus, 30 min after the injection of ginsenosides Rg1 or Re. Rb1 and Rd had no effect on choline acetyltransferase activity. Aged rats showed a smaller number of initial correct responses in the radial-arm maze and a lower choline acetyltransferase activity in the medial septum, diagonal band, caudate and hippocampus than did young adult rats. Repeated i.p. injections of Rg1 increased the number of initial correct responses and the activity of choline acetyltransferase in the medial septum, but not in the diagonal band, caudate and hippocampus, in aged rats. These results suggest that Rg1 and Re may contribute the ameliorative effects through an increase of choline acetyltransferase activity in the medial septum.

Aging↗
PubMed1997

Therapeutic value of neoadjuvant intra-arterial chemotherapy (cisplatin) and irradiation for locally advanced uterine cervical cancer.

We analyzed long-term treatment results in 51 patients with locally advanced uterine cervical carcinoma (IIB, 4; IIIB, 43; IVA, 4) treated with neoadjuvant intra-arterial (I-A) chemotherapy (cisplatin) via the uterine artery and irradiation. Thirty patients (58.8%) developed recurrence. Twelve had pelvic recurrence alone, 8 had distant metastases alone, and 10 had both pelvic and distant failure. The 5-year cumulative pelvic control rate, absolute survival rate, and disease-free survival rate were 55.3, 47.1, and 39.4%, respectively. Eight of 51 patients (15.7%) suffered late complications. These results suggest that our neoadjuvant I-A chemotherapy prior to irradiation has limited additional value for long-term prognosis in patients with locally advanced uterine cervical carcinoma.

Adult↗
PubMed1997

[Fast cine MR coronary angiography compared with conventional coronary angiography: criteria for coronary artery stenosis].

Magnetic resonance coronary angiography (MRA) was performed in 5 healthy volunteers and 13 patients to evaluate its diagnostic capability. Ten to 15 continuous cross sections were obtained for each coronary artery using fast cardiac cine MR (FASTCARD) with breath-hold, and reconstructed images were made. The control study showed good demonstration of the left main, proximal left anterior descending (Seg. 6) and proximal right (Seg. 1, 2) coronary arteries. Abnormal findings were classified as interruption, stenosis (severe or mild), irregularity, or decreased signal, and they were compared with the findings of conventional angiography in proximal segments (Seg. 1,2,5,6). Twelve of 15 lesions with significant stenosis (> 75%) were depicted as interruption or severe stenosis (sensitivity 80%). The sensitivity was 100% (6 of 6 lesions) in the right coronary artery and 67% (6 of 9 lesions) in the left coronary artery. The positive predictive value was 75% (12 of 16). Comparison at each segment revealed that the sensitivity, specificity and accuracy for interruption or severe stenosis were 92%, 79%, and 86%, respectively, for severe stenosis (> 90%), and 85%, 79%, and 83% for significant stenosis (> 75%). Interruption or severe stenosis on MRA is presumed to be an appropriate criterion for the detection of significant stenosis in the proximal coronary artery.

Adult↗
PubMed1997

[Noninvasive hemodynamic assessment of internal thoracic artery grafts using duplex echocardiography from supraclavicular fossa--a comparison with Doppler catheter method].

We evaluated the usefulness of noninvasive hemodynamic assessment of internal thoracic artery grafts (ITAGs) using duplex Doppler echocardiography from the supraclavicular fossa (transcutaneous pulsed Doppler method: PD method). Eighteen ITAGs were examined by PD method in comparison with Doppler catheter method using Doppler flowire (DC method). The hemodynamic indices used were the diastolic/systolic peak velocity ratio (DSVR) and the diastolic fraction of time-velocity integral (DF) in the ITAGs. A significant linear correlation was seen both in DSVR and DF between these two methods (p < 0.01). The subjects were assigned to two groups according to angiographic findings Group A (Gr-A: 5 grafts) with string sign including significant graft stenosis and group B (Gr-B 13 grafts) with good patency. In both PD and DC methods, DSVR and DF were significantly lower in Gr-A than in Gr-B (p < 0.01). The blood flow pattern was thus systolic dominant in the grafts with string sign, while it was diastolic dominant in the grafts with good patency. In some grafts in Gr-B, however, both DSVR ad DF were as low as that in Gr-A. Responding to pacing, Gr-B further increased both DSVR and DF, but Gr-A did not. As a result, the difference between both groups was further distinguished. In summary, ITAG function can be assessed by the noninvasive PD method. Interventions such as exercise, dobutamine infusion may make it more accurate, particularly in evaluating borderline data.

Aged↗
PubMed1996

Effects of ginsenosides on impaired performance caused by scopolamine in rats.

The effects of five structurally different ginsenosides on the performance impaired by scopolamine in rats were studied in a radial-arm maze. Ginsenoside Re had an ameliorating effect, but the ginsenosides, 20-O-glucosyl-protopanaxadiol, F2, Rf, and Rh1, did not. We reported previously that ginsenoside Rg1 had an ameliorating effect but that ginsenosides Rb1 and Rd did not (Yamaguchi et al., 1995, Psychoneuroendocrinology 20, 645). The sugar moieties at C(6) and C(20), which are possessed by Re and Rg1, seem to be indispensable for an ameliorating effect on the performance impaired by scopolamine.

Animals↗
PubMed1996

[Bowel injury caused by a catheter for Intraperitoneal chemotherapy--a case report].

A case of bowel perforation caused by a catheter used for intraperitoneal chemotherapy is reported. A 46-year-old woman underwent bilateral salpingo-oophorectomy, total hysterectomy and infracolic omentectomy for treatment of stage II c endometrioid carcinoma of ovary. Subsequently, the patient was treated with intraperitoneal administration of CBDCA through Port-A-Cath as well as intravenous CPA infusion every 5-6 weeks. Ten days after the 5th course of chemotherapy, she complained of low abdominal pain and fever of 37.9 degrees C, which resolved during a 6-day hospital stay, although her appetite remained poor. In the 6th course, CBDCA was administrated intravenously, because the intraperitoneal catheter became obstructed. Secondary cytoreductive laparotomy, which was performed 14 months after the primary surgery, revealed that the catheter of Port-A-Cath had penetrated the descending colon. Although intraabdominal injury by the catheter may be rare, it should be noted as one of complications when a patient is treated with intraperitoneal chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1995

Prognostic value of cervical size and pelvic lymph node status assessed by computed tomography for patients with uterine cervical cancer treated by radical radiation therapy.

PURPOSE: To determine the prognostic impact of cervical size and pelvic lymph node status assessed by computed tomography (CT) in uterine cervical carcinoma treated with irradiation alone. METHODS AND MATERIALS: Seventy patients with International Federation of Gynecology and Obstetrics (FIGO) Stage IIB and IIIB uterine cervical squamous cell carcinoma treated with a combination of external and high dose-rate intracavitary irradiation were entered into analyses. Univariate and multivariate analyses using the Cox regression model were performed to determine statistical significance of some tumor-related factors. RESULTS: There were no significant differences in pelvic control rate (PC), distant metastases-free rate (DMF), cause-specific disease-free survival rate (CSDFS) among subgroups with cervix < 60 mm in diameter. However, PC (p = 0.023), DMF (p = 0.000025), and CSDFS (p = 0.0023) were significantly lower for patients with cervix > or = 60 mm than < 60 mm. The 5-year CSDFS was 77.5% for < 60 mm, and 28.6% for > or = 60 mm. Pelvic node status assessed by CT scans had significant prognostic impact on outcome. the 5-year CSDFS rate was 84.9% for patients with no enlarged nodes, and 58.9% for those with enlarged nodes greater than 1 cm in minimum diameter (p = 0.023). Whereas PC was not significantly affected, the DMF was strongly correlated with nodal status (p = 0.00027). Pelvic node status was taken as an independent predictor for DMF (p = 0.019) on multivariate analysis. CONCLUSION: Although cervical size assessed by CT had limited prognostic value, pelvic node status assessed by CT is the significant prognostic factor for patients with uterine cervical carcinoma treated with radical irradiation.

Adult↗
PubMed1995

[Anesthetic management of cesarean section in a patient with dilated cardiomyopathy].

We report the anesthetic management of Cesarean section in a pregnant (31 weeks) woman with dilated cardiomyopathy. She had dyspnea and chest pain which were signs of congestive heart failure. The left ventricular ejection fraction was 38%. Anesthesia was induced and maintained with fentanyl, midazolam and vecuronium. There was no significant cardiovascular changes in the mother during the operation. The baby was apneic and showed no movement at birth, but he was immediately intubated and his condition became almost normal on the following day. In the anesthesiological management of Cesarean sections with cardiac disease, general anesthesia with fentanyl can be used to minimize cardiovascular changes in the mother as long as the baby is immediately resuscitated after delivery.

Adult↗
PubMed1995

Activin induces the expression of the Xenopus homologue of sonic hedgehog during mesoderm formation in Xenopus explants.

The Xenopus homologue of sonic hedgehog (Xhh) was detected in Xenopus embryos at stages 13 and 31 by RT-PCR, but it was not expressed in explants isolated from the animal hemisphere of Xenopus embryos at stage 8-9. Treatment of the animal cap with activin (1-100 ng/ml) induced the expression of Xhh. However, it was not induced by 100 ng/ml basic fibroblast growth factor (bFGF). Whole mount in situ hybridization confirmed the expression of Xhh in the animal cap treated with activin. The expression of Xhh induced by activin was not inhibited in the presence of cycloheximide, suggesting that Xhh is an early response gene induced by activin.

Activins↗
PubMed1995

Intra-arterial chemotherapy with cisplatin followed by radical radiotherapy for locally advanced cervical cancer.

Locally advanced cervical cancer has a dismal prognosis, with a high local failure rate and a poor survival rate. To improve the cure rate for advanced carcinoma of the cervix, we initiated a study of intra-arterial (I-A) chemotherapy with cisplatin via the uterine artery prior to definitive radiotherapy. I-A chemotherapy via the internal iliac artery has been used to treat advanced cervical cancer; however, access by way of the uterine artery has not been tested for this purpose. Thirty-four patients with central tumor > or = 5 cm in anteroposterior diameter observed on CT scans were treated with I-A chemotherapy. I-A chemotherapy consisted of unilateral catheterization of the uterine artery using 120 mg/m2 cisplatin. After assessment of I-A chemotherapy, all but 3 patients were treated with a combination of whole-pelvis external irradiation and intracavitary irradiation. The 3 patients underwent external radiotherapy alone. Twenty-seven of 34 patients treated were evaluable for response to I-A chemotherapy. Eleven patients (41%) experienced a partial response. Seventy-six percent of the 34 patients treated with I-A chemotherapy followed by radiotherapy exhibited a complete response by the end of treatment. Toxicity was well tolerated and no death due to treatment occurred. The 2- and 5-year actuarial survival rates were 64 and 55%, respectively. The crude incidences of pelvic recurrence and distant metastasis observed at a median follow-up of 54 months were both 47%. This study for locally advanced cervical cancer suggests there is benefit to be derived from our I-A chemotherapy followed by radical radiotherapy.

Adult↗
PubMed1995

Indirect effects in ecological interaction networks. II. The conjugate variable approach.

A new method called the conjugate variable approach for the analysis of indirect effects propagating through an ecosystem network is developed. For a given ecosystem of n species, the 2n variables representing the inflows and abundances of the n species are related in the n equations that define the system's steady states. There are 2n alternative ways of designating, for each species, either an inflow or an abundance variable as an independent variable and the other (i.e., its conjugate variable) as a dependent variable. Each of these alternative ways defines a unique configuration of constraints in the influence propagation through the ecosystem network. In particular, designating as independent variables the inflow variables of all but two focal species leaves their abundance variables free to change, thus leading to the evaluation of the total effect between the two focal species. On the other hand, choosing their abundance variables as independent variables to fix prohibits influence to pass through any of these intermediate species, thus selectively evaluating the direct effect between the two focal species. Any other way between these two extreme cases sets partial constraints on influence propagation, thus evaluating a partial effect between the two species. Four categories of effects between two species--inflow to abundance, abundance to abundance, inflow to inflow, and abundance to inflow--can be distinguished and explicitly evaluated in terms of community matrix elements.

Animals↗
PubMed1995

Indirect effects in ecological interaction networks. I. The chain rule approach.

A mathematical method for evaluating indirect effects propagated through ecosystems consisting of multiple species is developed. The time-backward expansion of the sensitivity matrix of a system at steady state represents the tracking back of the total effects received by species. Aggregating those portions of the total effect between two species that travel through a common path with various schedules gives the path partitioning of the total effect. From this path partitioning, a chain rule is derived that expresses the indirect effect transmitted through an individual path as the products of direct effects associated with the links constituting the path. The evaluation of indirect effects by this chain rule is applied to example systems to reveal the entire structure of influence propagation through the systems. The results of this application suggest three basic mechanisms through which indirect effects contribute to the complexity and contingency of species interactions: (i) the globalization of influence by bundles of long indirect paths, (ii) the amplification (or reduction) of effects by positive (or negative) cycles, and (iii) the alteration in sign of interactions between a pair of species due to the change in dominance among the effects carried by parallel paths connecting the species.

Animals↗
PubMed1995

Malignant trophoblastic neoplasms with different modes of origin.

The genetic origin of 24 trophoblastic neoplasms was determined using PCR polymorphisms. Based on pregnancy history, these tumors included nine postmolar trophoblastic tumors, 12 tumors preceded by live birth or abortion, and three nongestational tumors. Androgenetic origin was defined in eight post-molar trophoblastic tumors, and the remaining one might have arisen from a normal fertilization. Six tumors retained genetic features carried by the homozygous complete mole. Two tumors showed PCR polymorphism compatible with that of the heterozygous complete mole. All 12 tumors in the second class had alleles of both paternal and maternal contribution. However, discordance of sex between the antecedent pregnancy product and the tumor was recognized in three choriocarcinomas. The absence of paternal contribution suggested a parthenogenetic origin of three nongestational choriocarcinomas. The findings that PCR polymorphisms were either homozygous in certain loci or heterozygous in others may mean that the tumor was derived from a germ cell after meiosis I. As a result, at least three subtypes with different modes of origin were demonstrated in the 24 trophoblastic tumors. These findings underscore the importance of precise genetic marker analyses in a large series to clearly identify clinical and biologic characteristics of each subset of tumors.

Base Sequence↗
PubMed1994

[Role of postoperative irradiation for carcinoma of the uterine cervix: multivariate analysis of prognostic factors and patterns of failure].

We retrospectively analyzed the patterns of recurrence in 48 patients who underwent postoperative irradiation following surgery for carcinoma of the uterine cervix. The end points of pelvic control, distant metastases and disease-free survival were analyzed for parameters including FIGO stage, nodal status, degree of stromal invasion, histology and tumor size. Univariate and multivariate analyses showed that some prognostic parameters had little influence on pelvic control rate, but had a marked impact on the incidence of distant metastases and disease-free survival rate. These results suggest that postoperative irradiation improves pelvic control rate, but has little therapeutic benefit in preventing distant metastases or improving survival rate. In conclusion, we should give more consideration to adjuvant systemic therapy in addition to postoperative irradiation for high-risk patients.

Adult↗