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Biomedical subjects

T Furuta

Publications and source records attributed to T Furuta.

At least 19 recordsLinked to original sources
PubMed1992

Stable isotope dilution mass spectrometry for the simultaneous determination of cortisol, cortisone, prednisolone and prednisone in plasma.

A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of cortisol, cortisone, prednisolone and prednisone in human plasma is described. [1,1,19,19,19-2H5]Cortisol, [1,1,19,19,19-2H5]cortisone, [1,19,19,19-2H4]prednisolone and [1,19,19,19-2H4]prednisone were used as internal standards. Formation of the bismethylenedioxy-3-heptafluoro-n-butyryl (BMD-HFB) derivatives made possible the separation of the four corticosteroids with good gas chromatographic behaviour. The new double derivatization has been demonstrated to be of value for sensitive and selective quantification by this technique. Detection was performed by monitoring the molecular ion (M+) of the BMD-HFB derivatives for cortisone and prednisolone, the [M - 18]+ ion for cortisol, and the [M - 30]+ ion for prednisone. The method requires no complex corrections for contributions and provides good accuracy and precision.

Cortisone↗
PubMed1992

Reversible stepwise mechanism involving a carbanion intermediate in the elimination of ammonia from L-histidine catalyzed by histidine ammonia-lyase.

L-Histidine labeled with deuterium at the C-5' position of the imidazole ring, L-[5'-2H]histidine (His-5'-D), was used as a probe for investigating a stepwise reversible mechanism via a carbanion intermediate in the elimination of ammonia catalyzed by histidine ammonia-lyase (EC 4.3.1.3). The labeled L-histidine (His-5'-D) (2.45 mM) was incubated with histidine ammonia-lyase (200 units) from Pseudomonas fluorescens at pH 7.0 or 9.0 at 25.0 degrees C for 24 h. The time course of the reaction was examined to determine the rates of enzyme-catalyzed hydrogen exchange at C-5' of L-histidine and urocanic acid. The finding of the enzyme-catalyzed hydrogen exchange at C-5' of both L-histidine and urocanic acid in the presence of L-histidine provided a rational explanation for a stepwise reversible mechanism via a carbanion intermediate in the elimination reaction. The rate of increase in the concentration of urocanic acid exchanged with hydrogen (UA-5'-H) did not depend on the formation rate of urocanic acid and UA-5'-H was continuously formed at a constant rate (25.6 microM/h) even after the completion of urocanic acid formation. These observations suggested the presence of the reversible reaction of urocanic acid and a carbanion intermediate. Since there was only a minor contribution for the formation of UA-5'-H from L-histidine exchanged with solvent hydrogen (His-5'-H), the main pathway in the enzymatic reaction of His-5'-D must be the formation of UA-5'-D via a carbanion intermediate (carbanion-D). Regeneration of the carbanion-D from UA-5'-D by its reverse reaction and subsequent hydrogen incorporation at C-5' would contribute to a large extent for the formation of UA-5'-H. The stability of carbanion was also demonstrated to be approximately three times higher at pH 7.0 than at pH 9.0.

Ammonia↗
PubMed1992

Simultaneous determination of stable isotopically labelled L-histidine and urocanic acid in human plasma by stable isotope dilution mass spectrometry.

A capillary gas chromatographic-mass spectrometric method for the simultaneous determination of stable isotopically labelled L-histidine (L-[3,3-2H2,1',3'-15N2]histidine, L-His-[M + 4]) and urocanic acid ([3-2H,1',3'-15N2]urocanic acid, UA-[M + 3]) in human plasma was developed using DL-[2,3,3,5'-2H4,2'-13C,1',3'-15N2]histidine (DL-His-[M + 7]) and [2,3,5'-2H3,2'-13C,1',3'-15N2]urocanic acid (UA-[M + 6]) as internal standards. L-Histidine and urocanic acid were derivatized to alpha N-(trifluoroacetyl)-imN-(ethoxycarbonyl)-L-histidine n-butyl ester and imN-(ethoxycarbonyl)urocanic acid n-butyl ester. Quantification was carried out by selected ion monitoring of the molecular ions of the respective derivatives of L-His-[M + 4], DL-His-[M + 7], UA-[M + 3] and UA-[M + 6]. The sensitivity, specificity, precision and accuracy of the method were demonstrated to be satisfactory for measuring plasma concentrations of L-His-[M + 4] and UA-[M + 3] following administration of trace amounts of L-His-[M + 4] to humans.

Gas Chromatography-Mass Spectrometry↗
PubMed1992

Simultaneous determination of cortisol and cortisone in human plasma by stable-isotope dilution mass spectrometry.

A method for the simultaneous determination of cortisol and cortisone in human plasma was developed using capillary gas chromatography-mass spectrometry-selected ion monitoring. [2H5]Cortisol and [2H5]cortisone were used as internal standards. Cortisol and cortisone in plasma were determined from the peak-height ratios of the [M-31] fragment ions of the methoxime-trimethylsilyl derivatives of cortisol and [2H5]cortisol (m/z 605 and 610) and of cortisone and [2H5]cortisone (m/z 531 and 536). Sensitivity, specificity, precision, accuracy and reproducibility of the method were demonstrated to be satisfactory for measuring the circulating concentrations of cortisol and cortisone.

Cortisone↗
PubMed1992

Hepatic resection for a hepatocellular carcinoma larger than 10 cm.

Twenty-one patients with hepatocellular carcinoma (HCC) larger than 10 cm diameter were treated during the 18 year period from 1971 to 1988. The mean tumor size was 13 cm (range 10-18 cm). Nineteen patients (90.5%) had subjective symptoms. Eight patients (38.1%) had alpha-fetoprotein (AFP) levels over 10,000 ng/ml, and in 18 patients (85.7%) the levels were over 20 ng/ml. Nevertheless, only three (14.3%) were detected by AFP. Scintigraphy before 1981 and ultrasonography after 1982 appears to be most helpful for detection of HCC. Nineteen lesions (90.5%) were localized in the right hepatic lobe. Large HCC showed a low incidence of histologically verified concomitant cirrhosis (33%; 7 of 21) and a relatively well preserved hepatocellular function (indocyanine green test; 13.9 +/- 6.6%). Curative resection could be done for all 21 patients. There were three (14.3%) operative deaths. The 1-, 3-, and 5-year survival rates were 72.2, 32.9, and 8.2%, respectively. One patient who underwent a left hepatic lobectomy has survived for over 5 years, with recurrence. There were 14 recurrences (66.7%) in 21 patients: 11 were hepatic and three were in the lungs. In patients with large HCC, surgical resection should be done, provided the clinical status and hepatocellular reserves are adequate.

Carcinoma, Hepatocellular↗
PubMed1992

Preparation of multiply deuterium-labeled cortisol.

Cortisol labeled with four deuterium atoms at chemically stable sites ([9,11,12,12-(2)H4]cortisol, cortisol-d4) was prepared by hydrogen-deuterium exchange and reductive deuteration reactions. After protecting the C-17 dihydroxyacetone side chain of cortisone (cortisone-BMD), hydrogen-deuterium exchange was carried out with 6.5% NaOD in MeOD, which was followed by protection of the C-3 carbonyl as the semicarbazone. Subsequent reductive deuteration at C-11 with NaBD4 followed by removal of exchangeable deuterium under the same exchange-reaction conditions in a medium of 6.5% NaOH in MeOH and deprotection afforded the desired cortisol-d4 with high isotopic content (d3, 21.2%; d4, 78.1%; d5, 0.74%). The method was applied to the synthesis of cortisol labeled with nine deuterium atoms [( 1,1,9,11,12,12,19,19,19-(2)H9]cortisol, cortisol-d9) starting from [1,1,19,19,19-(2)H5]cortisone (cortisone-d5).

Cortisone↗
PubMed1992

Trigeminal neurinoma presenting with intratumoral hemorrhage: report of two cases.

We report 2 cases of trigeminal neurinoma presenting with spontaneous intratumoral hemorrhage. There are only 2 similar cases reported in the literature. Presenting symptoms were headache, diplopia, disturbed consciousness and trigeminal disturbance with sudden onset. CT scan showed a typical fluid-fluid level within low-density mass in the cerebellopontine angle in one case. On MRI, one case showed a typical fluid-fluid level on T2-weighted image and another one had mixed signal intensities including hyper- and hypointensities on both T1- and T2-weighted images. Histologically, increased vascularity, consisting of dilated and thin-walled vessels presenting telangiectatic or cavernous angiomatous appearances were observed in the specimens in both cases. The size of these tumors was about 3 cm each in diameter. Risk factors for hemorrhage appear to be large tumor size and increased vascularity.

Aged↗
PubMed1992

Neurinomas presenting as spontaneous intratumoral hemorrhage.

Massive intratumoral or subarachnoid hemorrhage from neurinomas is very rare. The authors report on six patients, four men and two women, with neurinomas that presented as spontaneous intratumoral hemorrhage. The average age of the patients was 56.8 years (range, 31-74 years). Neurinomas originated from the acoustic nerve in four patients and from the trigeminal nerve in two. Four cases were accompanied by the sudden occurrence of clinical symptoms such as headache, double vision, and hemisensory or motor disturbance. The maximum diameter of the tumors ranged from 2.8 to 3.8 cm (average, 3.1 cm). Histological examinations showed massive hemorrhage and increased vascularity, with dilated, thin-walled vessels, in all cases. The size of the tumor and the increase in vascularity with dilated, thin-walled vessels within neurinomas are important pathogenetic factors of hemorrhage. When sudden onset of symptoms or rapid worsening of chronic symptoms occurs in neurinomas, intratumoral or subarachnoid hemorrhage should be considered as a possible cause, and magnetic resonance imaging can be an important tool in obtaining correct diagnosis.

Adult↗
PubMed1992

Relationship between the effects on bacterial activity of selected disinfectants and the hydrophobic characters of dibasic acid diesters.

We prepared test solutions which contained 80% (v/v) ethanol and 0.2% (w/v) chlorhexidine (CH) or benzalkonium chloride (BC) with or without a dibasic acid diester. After complete evaporation of the ethanol from the solution on filter paper, an overnight broth culture (Staphylococcus aureus) was repeatedly inoculated onto the filter paper, and viable bacterial counts were measured at 5 min after the last inoculation. By comparison with viable counts for CH or BC alone, we estimated the potentiating effects of dibasic acid diester on the bactericidal activity of CH or BC, and confirmed that this activity of the two disinfectants was potentiated in the presence of certain compounds in the homologs of di-n-butyl esters of aliphatic dibasic acid, and di-alkyl esters of adipic and phthalic acid. Diisobutyl adipate, one of the most effective diesters, substantially enhanced the bactericidal activities of benzethonium chloride, cetyl pyridinium chloride and didecyl dimethyl ammonium chloride, as well as CH and BC, but not those of polyhexamethylene biguanide or alkyldiaminoethyl glycinate. The potentiating effects of dibasic acid diesters observed for both CH and BC seemed to be affected by the hydrophobic character of these diesters themselves and are also expressed well by a particular quadratic equation as a function of these characters: namely, capacity factors, as determined by high-performance liquid chromatography.

Chemical Phenomena↗
PubMed1992

Chemical modification of an antitumor alkaloid, 20(S)-camptothecin: glycosides, phosphates and sulfates of 7-ethyl-10-hydroxycamptothecin.

Water-soluble derivatives having the lactone ring intact were synthesized starting from 7-ethyl-10-hydroxycamptothecin (1). Glycosides (2) of the phenolic hydroxyl group of 1 were obtained by reaction with acetylated alpha-bromosugars in acetone or aqueous acetone in the presence of potassium carbonate, followed by deprotection. Phosphates (3) were prepared by reaction of 1 with phosphoryl chloride in pyridine or with dibenzylchlorophosphoridate. Sulfates (4) were obtained by reaction of 1 with sulfur trioxide-pyridine complex in the presence of a tertiary amine. The organic ammonium salts of monophosphate (3p) and sulfates (4a and 4b) showed significant activity against L1210 in vivo.

Animals↗
PubMed1992

Long-term changes of infarct-related lesions. Comparison of angiograms in recent and remote phases.

Coronary angiograms recorded in the recent phase of an acute myocardial infarction in 73 patients were compared with those taken in the remote phase at least 12 months from the onset of the infarction. The infarct-related lesions of 23 patients (32%) showed a regression of 20% or more. Analysis of recent-phase angiograms proved that any one of several features (long-segment narrowing, intraluminal thrombus, flap-like structure or atheromatous ulceration) was present more frequently in the lesions showing a marked regression (18/23, 78%) than in the lesions without regression (15/40, 38%) (p less than 0.01). Thus, the narrowings of infarct-related lesions seen on the recent-phase angiograms regress frequently. The possibility of regression can be predicted from the angiographic features.

Coronary Angiography↗
PubMed1992

Clinical significance of residual collaterals immediately after successful coronary angioplasty.

The clinical significance of collaterals visible on angiography immediately after successful percutaneous transluminal coronary angioplasty (PTCA) was analyzed in 221 patients who underwent successful PTCA for coronary arteries receiving collaterals. Filling of the collaterals was classified as good; filling the entire epicardial segment of the stenosed site, fair; partially filling the epicardial segments distal to the stenosed site, and faint; visible but not filling the epicardial segments of the diseased vessel. Fifteen of 41 good collaterals remained good or fair on angiography immediately after PTCA. Among the 114 fair collaterals, 26 remained fair and 20 of 66 faint collaterals remained visible on the angiogram immediately after PTCA. There was no relationship between the degree of residual stenosis after PTCA and the degree of residual collaterals. Repeat coronary angiography was obtained in 156 patients. There was no correlation between the presence, absence or degree of collaterals observed on angiography immediately after successful PTCA and the rate of restenosis. Thus, collaterals to the vessels dilated by PTCA often remain on the angiogram immediately after PTCA and are dependent primarily on their degree before dilation. They do not indicate inadequate dilation or predict restenosis.

Aged↗
PubMed1992

Preliminary results of interstitial 192Ir brachytherapy for malignant gliomas.

Twenty-six patients with recurrent or unremovable malignant gliomas were treated by interstitial brachytherapy with iridium-192 seeds. Stereotactic implantation of the afterloading catheters using the Brown-Roberts-Wells computed tomography (CT)-guided stereotactic system was performed in 24 patients and surgical implantation in two patients with pontine glioma. The response to therapy was measured by serial CT, magnetic resonance imaging, and clinical examination. Tumor regression was seen in 17 patients 1-3 months after implantation. Tumor progression was seen in only three patients. After interstitial brachytherapy, the most commonly observed CT finding was central low density. Median survival time was 18 months after implantation. Autopsies in five patients revealed the delayed effects of radiation injury such as typical vascular changes, microcalcification, and coagulative necrosis in the implant area and tumor recurrence at the periphery. The results suggest that brachytherapy is not curative but prolonged the median survival time by 6 months.

Adult↗
PubMed1992

[Evaluation of proposed criteria of disk susceptibility testing for tosufloxacin and lomefloxacin in NCCLS guidelines and WHO standards].

Disk diffusion zone diameter breakpoint criteria for Tosufloxacin and Lomefloxacin were tentatively established by correlating MICs with 1-, 5- and 10 micrograms of Tosufloxacin disk inhibitory zone diameters and with 10 micrograms of Lomefloxacin disk of those to 418 clinical isolates representing 32 species. We recommend 5 micrograms disks for Tosufloxacin with the following breakpoints: Susceptible (MIC, less than or equal to 0.5 microgram/ml), greater than or equal to 22 mm; intermediate, 17 to 21 mm; and resistant (MIC, greater than or equal to 2.0 micrograms/ml), less than or equal to 16 mm. We recommend 10 micrograms disks for Lomefloxacin with the following breakpoints: Susceptible (MIC, less than or equal to 2.0 micrograms/ml), greater than or equal to 21 mm; intermediate, 16 to 20 mm; and resistant (MIC, greater than or equal to 8.0 micrograms/ml), less than or equal to 15 mm. Using these criteria for Tosufloxacin and Lomefloxacin, the occurrence rate of major errors in judging susceptibility and resistance was 0.48%.

Anti-Infective Agents↗
PubMed1992

[Left ventricular volume decrease during isovolumic relaxation period in gated blood pool scintigraphy: observations in patients with old myocardial infarction].

We studied left ventricular (LV) volume decrease, namely, the downward displacement of the LV volume curve, during the isovolumic relaxation period on the time-activity curves obtained from gated blood pool scintigraphy in patients with old myocardial infarction (OMI). To evaluate the mechanism and clinical significance of this phenomenon, 113 consecutive patients with OMI undergoing gated blood pool scintigraphy, left ventriculography, and Doppler echocardiography were studied. 1. This phenomenon was observed only in patients with anterior OMI (13 of 51 patients: 25%). Presence (Group I) or absence (Group II) of this phenomenon was examined. 2. On left ventriculography, dyskinetic or aneurysmal wall motion was observed in the anterior or apical region more frequently in Group I (11 of 13 patients: 85%) than in Group II (20 of 51 patients: 39%) (p < 0.001). 3. Doppler echocardiography showed that the presence of abnormal LV reversed flow over 20 cm/sec from the apex to the base during the isovolumic relaxation period is more frequent in Group I (7 of 13: 54%) than in Group II (4 of 51: 8%) (p < 0.001). These results suggested that this blood shift in the left ventricle is attributed to asynchronous LV relaxation occurring simultaneously with LV volume decrease on gated blood pool scintigraphy. In conclusion, this phenomenon suggests the presence of asynchronous LV relaxation.

Echocardiography, Doppler↗
PubMed1992

[Cool storage of fetal rat brain for neural transplantation].

The availability, storage and transportation of donor tissue are major practical problems associated with the potential use of grafted neural cell replacements in neurodegenerative diseases. The capacity to collect and maintain viable fetal neural tissue would facilitate possible clinical applications, and provide opportunities to study various neural diseases. In the present study, we examined the effect of cool storage on the survivability of intraventricular rat fetal ventral mesencephalic grafts (gestational days 15). In all experiments, fetal ventral mesencephalons were dissected out under a dissecting microscope in calcium-free magnesium-free buffer (CMF: 0.15 M NaCl, 0.008 M Na2HPO4, 0.0027 M KCl, 0.0015 M KHPO4, 0.026 M NaHCO3, with 0.1% glucose, 100 micrograms/ml streptomycin, 2.5 micrograms/ml fungizone). Fetal mesencephalic tissue was grafted into the lateral ventricle following pregraft refrigeration in calcium-free magnesium-free buffer at 4 degrees C. Fetal mesencephalic tissue was hibernated for 5, 12, 16, 20, 24, 28, 32 hours (group A, B, C, D, E, F and G, respectively). As a control group, fetal mesencephalic tissue was grafted into the lateral ventricle immediately after dissection. Grafted fetal mesencephalic tissue which had been hibernated for 16 hours or less survived well. There were no significant decreases in the size of grafts among group A, B, C and the control group. In group A, B, C and the control group, clusters of TH-positive neurons and dense networks of neuritic profiles within the grafts provided a morphological appearance reminiscent of the dendritic bundles that characterize the zone reticulate of the substantia nigra in situ.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Successful treatment with steroid pulse therapy in a case of dilated cardiomyopathy associated with mesangial proliferative glomerulonephritis].

A 28-year old male was admitted to our hospital because of heart failure, chronic renal failure and nephrotic syndrome. Light microscopic findings of his kidney biopsy showed proliferation of mesangial cell and marked narrowing the lumina of small arteries and arterioles. The changes of these small vessels were not those of typical vasculitis, when we considered his age and his past history. The diagnosis of dilated cardiomyopathy was made by the findings in echocardiography and cardiac catheterization. Since the heart failure and renal disease seemed to be simultaneous initiated, it was supposed that the diseases in two organs were caused by a common pathogenesis related to that of vasculitis. When steroid pulse therapy was adopted, both of cardiac and renal function responded to this treatment (ejection fraction from 26% to 52%, creatinine clearance from 48 to 62 ml/min). Increase of CD56 positive cells (natural killer cells) in peripheral blood was ameliorated after the treatment. These findings suggest that cellular immunity may be concerned with the pathogenesis of the combination of dilated cardiomyopathy and renal disease in this case.

Adult↗