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Biomedical subjects

T Takano

Publications and source records attributed to T Takano.

At least 145 records · Page 8Linked to original sources
PubMed2000

Serum dehydroepiandrosterone, dehydroepiandrosterone sulfate, and pregnenolone sulfate concentrations in patients with hyperthyroidism and hypothyroidism.

BACKGROUND: Dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEA-S) have been suggested to have protective effects against cardiovascular disease, cancer, immune-modulated diseases, and aging. We examined serum concentrations of DHEA, DHEA-S, and pregnenolone sulfate (PREG-S) in patients with thyroid dysfunction. METHODS: Steroids extracted with methanol from serum sample were separated into an unconjugated fraction (DHEA) and a monosulfate fraction (DHEA-S and PREG-S), using a solid-phase extraction and an ion-exchange column. After separation of unconjugated steroids by HPLC, the DHEA concentration was measured by enzyme immunoassay. The monosulfate fraction was treated with arylsulfatase, and the freed steroids were separated by HPLC. The DHEA and PREG fractions were determined by gas chromatography-mass spectrometry, and the concentrations were converted into those of DHEA-S and PREG-S. RESULTS: Serum concentrations of DHEA, DHEA-S, and PREG-S were all significantly lower in patients with hypothyroidism (n = 24) than in age- and sex-matched healthy controls (n = 43). By contrast, in patients with hyperthyroidism (n = 22), serum DHEA-S and PREG-S concentrations were significantly higher, but the serum DHEA concentration was within the reference interval. Serum concentrations of these three steroids correlated with serum concentrations of thyroid hormones in these patients. Serum albumin and sex hormone-binding globulin concentrations were not related to these changes in the concentration of steroids. CONCLUSIONS: Serum concentrations of DHEA, DHEA-S, and PREG-S were decreased in hypothyroidism, whereas serum DHEA-S and PREG-S concentrations were increased but DHEA was normal in hyperthyroidism. Thyroid hormone may stimulate the synthesis of these steroids, and DHEA sulfotransferase might be increased in hyperthyroidism.

Adult↗
PubMed2000

[Clinical significance of pressure measurement in the infarct-related coronary artery in acute myocardial infarction: evaluation of variables predicting recovery of left ventricular function in the convalescent stage].

Early reperfusion and good antegrade flow are essential in restoring better regional left ventricular function in acute myocardial infarction, but they do not always correlate with the extent of recovery. This study evaluated coronary circulation using the new "pressure wire" technique to measure the direct pressure of the coronary circulation including antegrade and collateral flow before and after reperfusion in patients with acute myocardial infarction, and to clarify the influence of these variables on recovery of left ventricular function in the convalescent stage. Fifty six consecutive patients with first acute myocardial infarction underwent percutaneous transluminal coronary angioplasty(PTCA) for totally occluded or severely narrowed infarct-related lesion and evaluation of coronary circulation using pressure wire. Left ventriculography was analyzed at 1 month after the onset in 41 patients. Treatment variables including reperfusion time, reperfusion modality, Thrombolysis in Myocardial Infarction(TIMI) grade after PTCA, and pressure wire variables were compared with parameters of left ventricular function. Reperfusion time was not related to regional wall motion evaluated by the SD chord of left ventriculography in the infarcted zone. Pressure wire measurements showed a correlation between fractional flow reserve measured after PTCA and infarcted regional wall motion(r = 0.558, p < 0.01). Patients with infarct-related lesion in the right coronary artery showed the magnitude of left ventricular regional wall motion was related to fractional collateral flow reserve(maxQc/Qn) during PTCA(r = 0.768, p < 0.05), but no such relationship was observed in patients with infarct-related lesion in the left anterior descending artery. Fractional flow reserve measured after PTCA varied widely in patients with the same TIMI flow grade, so did not vary with it. The pressure wire technique enables assessment of the collateral circulation distal to infarct-related lesion quantitatively before reperfusion in patients with acute myocardial infarction. The fractional flow reserve derived by coronary pressure after reperfusion was significantly related to the recovery of regional wall motion in the infarcted area in the convalescent stage. The fractional flow reserve after reperfusion with PTCA is a better parameter than TIMI flow grade for predicting recovery of regional left ventricular function after myocardial infarction.

Angioplasty, Balloon, Coronary↗
PubMed2000

[Molecular-based diagnosis of thyroid carcinomas by detecting cancer-specific mRNAs].

Molecular-based diagnosis of thyroid carcinomas can be more easily established by utilizing specific mRNAs that are restrictedly expressed in cancer tissues. In light of this aspect, we searched for cancer-specific mRNAs using sequence specific-differential display(SS-DD) and serial analysis of gene expression(SAGE). By these techniques, we found several mRNAs that efficiently distinguished benign and malignant tissues. Among these, oncofetal fibronectin(onfFN) mRNA was expressed only in thyroid papillary and anaplastic carcinomas and it was considered the most preferable target for molecular-based diagnosis of these carcinomas. In a previous study, we introduced a new method of preoperative diagnosing thyroid carcinomas. This technique, aspiration biopsy-RT-PCR(ABRP), allows us to simultaneously perform cytological and molecular-based diagnoses by extracting RNA from leftover cells within the needle used for fine needle aspiration biopsies(FNABs). ABRP provides both RNA information and cytological diagnosis without further invasion to the patient. We demonstrated that by ABRP detection of onfFN mRNA in FNABs, papillary and anaplastic carcinomas may be accurately diagnosed preoperatively. Further, by real-time monitoring RT-PCR measurement of onfFN mRNA, a fully automated system was established.

Humans↗
PubMed2000

[Nation-wide survey on hemimegalencephaly in Japan].

We report here 38 Japanese patients with hemimegalencephaly collected by a national survey study. All the patients were sporadic. There was no familial occurrence or sex difference. Some patients had basic diseases: hypomelanosis of Ito in 3 cases and organic nevus syndromes in 8. Most patients had hemiparesis, and 11 were bed-ridden. All except for 3 patients had mental retardation, being profound in half of them. There was no correlation between the side of hemimegalencephaly and clinical symptoms. All patients had epileptic seizures, which first appeared within 24 hours after birth in 4 cases, within 7 days in 7, within a month in 2, within 6 months in 10, and within a year in 4. Antiepileptic drugs were not very effective for controlling seizures. In 7 patients, however, functional hemispherectomy resulted in seizure control and improved development. The patients whose epileptic symptom occurred earlier tended to be more severe in clinical symptoms.

Adolescent↗
PubMed2000

Serum soluble fas level as a prognostic factor in patients with gynecological malignancies.

The Fas-Fas ligand system is important in apoptosis mediated by CTLs and natural killer cells. The suppression of apoptosis contributes to carcinogenesis, as well as to a resistance to chemotherapy and radiotherapy. Circulating soluble Fas (sFas), which is generated by alternative mRNA splicing, can antagonize cell-surface Fas function. We investigated sFas levels in 64 patients with gynecological malignancies (28 cervical carcinomas, 18 endometrial carcinomas, and 18 ovarian carcinomas) and in 24 healthy female donors by using a Fas-specific ELISA. In each carcinoma group, serum sFas demonstrated a statistically significant elevation relative to levels in normal controls (P < 0.0001). Levels of serum sFas in patients with advanced cancer (FIGO stages III and IV) significantly exceeded those in patients with localized cancer (FIGO stages I and II) or those in normal control subjects (P < 0.0001). We divided the patients into two groups based on the level of serum sFas and examined the relationship between serum sFas levels and survival. No deaths occurred in the groups with cervical and endometrial cancer with a serum sFas level < 1.5 ng/ml. Survival rates in groups with cervical carcinoma, endometrial carcinoma, and ovarian carcinoma with a serum sFas level < 1.5 ng/ml exceeded those in groups with sFas levels of 21.5 ng/ml (P < 0.001, P = 0.128, and P = 0.012, respectively). Proportional hazard models demonstrated that serum sFas level was a statistically significant factor (P = 0.0196) for survival, as well as histological grade (P = 0.0168) in ovarian carcinoma.

Adult↗
PubMed2000

Control system for an implantable rotary blood pump.

Rotary blood pumps can be used for long-term left ventricular assist devices. These pumps have several advantages over the conventional pulsatile pumps including smaller size, higher efficiency, and simple design and construction. However, one of the difficulties associated with the rotary blood pump is the proper control method to maintain an optimum flow rate in different physiological conditions. The rotary blood pump can be controlled by two methods. The first is to utilize the measured pump flow rate from its servo signal. The second is to detect and avoid abnormal pumping conditions such as; back flow and sudden increase in the pressure head. This abnormal situation typically occurs from excessive suction of blood when there is a functional or mechanical occlusion in the inflow cannula. The ultrasound flow meter is durable and reliable but it is difficult to continually monitor the blood flow rate of an implantable pump. Therefore, another method is needed instead of the continuous flow monitoring. One chronic calf having an LVAD was subjected for the development of this control system. This calf survived more than 6 months. Voltage, current, motor speed, heart rate and the pump flow rate were recorded and stored at 30-min intervals in a computer. Utilizing these parameters, attempts were made (1) to achieve indirect flow assessments and (2) to reveal abnormal operating parameters of the centrifugal pump (1). Indirect flow measurement, the predicted pump flow rate was calculated from these pump derived parameters (required power, motor speed and heart rate). The value of the coefficient of determination (R) between the measured and estimated pump flow rate was 0.796. (2) Abnormal operating indicator, there was an association between the required current and pump flow waves. The current was differentiated, and then calculated to the power of the differentiated current. The normal range of this value was 0.02+/-0.54. In abnormal conditions, this abnormal operating indicator increased 500 times. The predicted flow estimation method and abnormal operating indicator were available from intrinsic operating parameters of the pump and need no sensors. These two methods were simple, yet they are possibly effective and reliable servo control methods for a rotary blood pump.

Animals↗
PubMed2000

[Clinical investigation of inhomogeneity of washout rate in dipyridamole stress thallium scintigraphy: implication of new parameter for the indication of coronary intervention].

OBJECTIVES: The standard deviation of the washout rate in dipyridamole stress thallium-201 myocardial single photon emission computed tomography (SPECT) was correlated with the severity of coronary artery lesions and the viability of ischemic myocardium to provide a new quantitative parameter for judging indications for coronary intervention therapy. METHODS: Dipyridamole stress thallium-201 SPECT was performed in 233 patients for differential diagnosis of angina pectoris during the 40 months beginning in October 1995, and 57 patients were investigated who underwent coronary angiography within 6 months of the SPECT. The washout rate standard deviation (WRSD) in 720 fractions in the bull's-eye view of the SPECT was determined. The conventional washout rate extent score (WRES) and washout rate severity score (WRSS) on the washout rate map were also determined. Based on the coronary angiography findings, patients were divided into 3 groups: zero-vessel group (zero-vessel disease, n = 20), one-vessel group (one-vessel disease, n = 18), and multivessel group (two- or three-vessel disease, n = 19). The patients were also divided into 2 other groups: Int group (n = 21), who underwent coronary intervention therapy, and Med group (n = 36), in whom intervention therapy was not indicated. RESULTS: All 3 parameters, WRSD, WRES and WRSS, showed significant differences between the 3 groups, and more coronary arteries affected by coronary artery stenosis were associated with higher WRSD (zero-vessel group: 5.4 +/- 1.5, one-vessel group: 7.0 +/- 3.7, multivessel group 11.4 +/- 6.7; p < 0.001), WRES (3.3 +/- 5.0, 15.5 +/- 18.1, 23.0 +/- 25.4; p < 0.01), and WRSS (1.4 +/- 2.8, 25.4 +/- 40.2, 84.8 +/- 114.5; p < 0.01). WRSD (Med group: 5.9 +/- 2.7, Int group: 11.3 +/- 6.4; p < 0.001), WRES (7.3 +/- 12.0, 24.7 +/- 24.9; p < 0.01), and WRSS (9.9 +/- 29.3, 82.9 +/- 108.2; p < 0.01) were all significantly higher in the Int group compared with the Med group. There were significant correlations between Gensini's score and WRSD (r = 0.51, p = 0.00005), WRES (r = 0.37, p = 0.005), and WRSS (r = 0.29, p = 0.03). The cutoff values for the indications for coronary intervention therapy were established for each of the 3 parameters as the maximum value of average sensitivity and specificity as follows: WRSD > 9.0 (sensitivity 0.62, specificity 0.89, positive predictive value 0.76, negative predictive value 0.24); WRES > 10.0 (0.62, 0.69, 0.54, 0.46, respectively); WRSS > 13.0 (0.62, 0.83, 0.68, 0.32, respectively). WRSD > 9.0 had the highest specificity and positive predictive value for judging indications. CONCLUSIONS: A new quantitative parameter, WRSD > 9.0, suggests the presence of viable and curable ischemic myocardium as an indication for coronary intervention therapy.

Aged↗
PubMed2000

Focal nodular hyperplasia of the liver: direct evidence of circulatory disturbances.

Focal nodular hyperplasia of the liver is a lesion characterized by a well-circumscribed region of hyperplastic liver parenchyma and contains a stellate fibrous scar. The lesion is thought to be because of liver-cell hyperplasia that is caused by focal circulatory disturbances. We describe here a pediatric case of this lesion that provided direct histopathologic evidence of circulatory disturbances. We identified arterial and portal thrombi, as well as recanalization of arteries in the nodule. Hepatic necrosis was also seen in the lesion. We speculate that thrombosis of the hepatic artery and/or portal vein was the cause of hepatic necrosis and that reperfusion following hepatic arterial recanalization resulted in nodule formation. Although there was no stellate scar present in our case, the presence of bile ductular proliferation at the periphery of the nodule was helpful in distinguishing this lesion from adenoma and hepatocellular carcinoma. The early stage of nodular formation may explain the lack of a stellate scar in our case. The patient was treated earlier with actinomycin D and vincristine following surgical excision of Wilms' tumor. It is possible that such chemotherapy contributed to thrombosis in our case.

Antineoplastic Agents↗
PubMed2000

Development of a new silicone membrane oxygenator for ECMO.

Two types small and efficient ECMO oxygenators were developed utilizing the most up to date hollow fiber technology. Newly silicone hollow fibers possess sufficient mechanical strength while maintaining ultra thin walls of 50 micro meter. Two types of oxygenators were made with this fiber. The fiber length for the type 1 module is 150mm with a priming volume 194 cc (surface area 1.3 m(2)) and type 2 has a fiber length of 100 mm with a 144 cc priming volume (the surface area 0.8 m(2)). The studies were performed at 0.5, 1.0 and 2.0 L/min of blood flow and these oxygenators demonstrated. O(2) gas transfer rate of 69+/-4 ml/min/L for type 1 and 68+/-6 ml/min/L for type 2. The CO(2) gas transfer rate was 25+/-2 ml/min/L for type 1 and 32+/-2 ml/min/L for type 2. These results demonstrate type 2 oxygenator has similar gas exchange capabilities to those of Kolobows' oxygenator which has about 2.0 times larger surface area. Additionally, comparative hemolysis tests were preformed with this new oxygenator and the Kolbow. The NIH value was 0.006 (g/100 L) for the type 1 oxygenator and 0.01 (g/100 L) for the Kolbow oxygenator. These results suggested that this ECMO oxygenator had sufficient gas exchange performance in spite of being smaller and induced minimal blood damage.

Equipment Design↗
PubMed2000

[A Warthin's tumor showing extensive necrosis].

Warthin's tumors are one of the most easily recognizable tumors using light microscopy. However, histopathological diagnosis is difficult in a few cases when characteristic cystic cavities with papillary walling and underlying lymphoid stroma are obscured by reactive changes. We describe a case of an extirpated Warthin's tumor of the right parotid gland which demonstrated extensive necrosis, squamous metaplasia and xanthomatous inflammation. No characteristic structure for this tumor was noticed in a section of an initially sampled specimen. As a result, a destroyed fistula was suspected. An additional sampling was performed to confirm the diagnosis and the sampled specimen fortunately demonstrated the diagnostic structure of a Warthin's tumor excluding malignancy. An awareness of the morphological variation seen in this tumor should lead to additional sampling of specimens, thereby preventing erroneous interpretation.

Adenolymphoma↗
PubMed2000

Changes in the lifestyle of Mongolian pastoralists in China in connection with urbanization.

The objective of this study was to elucidate changes in the health-related lifestyle of Mongolian pastoralists in China in connection with their urbanization. A total of 592 people participated in a survey that included a medical examination and an interview questionnaire. Files of 72 pastoral Mongolians, 78 urban Mongolians, 380 urban Han/Man and 21 urban Hui were used for this analysis. Urban Mongolians consumed meat and milk products less frequently than did pastoral populations (p < 0.001), and consumed fish and vegetables more frequently than did pastoral populations (p < 0.001). Urban Mongolian consumed mutton, beef, rengyo fish, milk, milk tea, curd, butter, yogurt, and sheep milk less frequently (p < 0.05) and pork, sword fish, and dried milk more frequently (p < 0.05) than pastoral Mongolian. Male pastoral Mongolians were more likely to drink and smoke than were urban Mongolians (p < 0.01), urban Han/Man (p < 0.01), or urban Hui (p < 0.01). The lifestyles of pastoral Mongolians in Inner Mongolia, China have changed in connection with urbanization. Understanding of the traditional pastoral lifestyle and the urban-living acculturation process will contribute to maximizing the positive impacts of urbanization on people's health in Inner Mongolia.

Acculturation↗
PubMed1999

Method for the simultaneous determination of losartan and its major metabolite, EXP-3174, in human plasma by liquid chromatography-electrospray ionization tandem mass spectrometry.

A liquid chromatography-electrospray ionization tandem mass spectrometric method was developed for the simultaneous determination of losartan and its major active metabolite, EXP-3174, in human plasma. The two analytes and the internal standard (DuP-167) were extracted from plasma under acidic conditions by using solid-phase extraction cartridges containing a sorbent of copolymer, poly(divinylbenzene-co-N-vinylpyrrolidone). The analytes were separated by LC equipped with a reversed-phase C18 column, and introduced into the mass spectrometer via the electrospray ion source with pneumatically-assisted nebulization. For LC-MS-MS samples, an isocratic mobile phase consisting of [0.1% triethylamine-0.1% acetic acid (pH 7.1)]-acetonitorile (65:35, v/v) was used, and the assay was monitored for the negative fragment ions of the analytes. The method demonstrated linearity from 1 to 1000 ng/ml for both losartan and EXP-3174. The limit of quantification for both compounds in plasma was 1 ng/ml. This assay method may be useful for the measurement of levels of the two compounds in clinical studies of losartan.

Antihypertensive Agents↗
PubMed1999

Experimental schizencephaly induced by Kilham strain of mumps virus: pathogenesis of cleft formation.

The pathogenesis of cleft formation in schizencephaly was analyzed by examining the brain lesions produced by the infection of the Kilham strain of mumps virus during the period of neuronal migration in hamsters. Mumps virus antigen was detected in the neuroepithelial cells within the ventricular zone, the choroid plexus in the lateral ventricles, and vimentin-immunoreactive radial glial fibers. The main pathological findings were cerebral hemorrhage, neuronal necrosis, microsulci on the cerebral cortex and cleft formation through the entire thickness of the cerebral mantle. The clefts seen in these experiments were lined by embryonal elements such as neuroepithelial cells and germinal cells. Based on these results and the original definition by Yakovlev and Wadsworth, the following two conclusions were suggested. First, the mumps virus localized to the neuroepithelial cells within the ventricular zone and the radial glial fibers may induce a destructive process and subsequent anomalous neuronal migration, resulting in cleft formation. Second, the formation of the ventricular cleft extending to the pial surface, which should be complete before the cortical infolding appears, is necessary in order to produce the characteristic cleft in schizencephaly which is associated with the pial-ependymal seam.

Animals↗
PubMed1999

Preoperative diagnosis of thyroid papillary and anaplastic carcinomas by real-time quantitative reverse transcription-polymerase chain reaction of oncofetal fibronectin messenger RNA.

The restricted expression of oncofetal fibronectin (onfFN) mRNA in thyroid papillary and anaplastic carcinomas was recently reported. In this study, we measured the copy number of onfFN mRNA in RNAs extracted from fine needle aspiration biopsies by real-time quantitative reverse transcription-PCR using thyroglobulin mRNA as an internal control. By measuring the onfFN:thyroglobulin mRNA ratio, preoperative aspirates from 31 papillary carcinomas and an anaplastic carcinoma can be distinguished from those from 5 adenomatous goiters, 5 follicular adenomas, and 4 follicular carcinomas. Thus, quantification of onfFN by real-time quantitative reverse transcription-PCR may be useful for the preoperative diagnosis of papillary and anaplastic carcinomas.

Base Sequence↗