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Biomedical subjects

T Usui

Publications and source records attributed to T Usui.

At least 19 recordsLinked to original sources
PubMed1992

Determination of a new bisphosphonate, YM175, in plasma, urine and bone by high-performance liquid chromatography with electrochemical detection.

A high-performance liquid chromatographic method for the determination of disodium dihydrogen(cycloheptylamino)methylene-bisphosphonate monohydrate (YM175) in plasma, urine and bone is described. Plasma obtained in high-dose animal studies is pretreated by Method A, a simple method using 1 ml of plasma, which is based on deproteinization of plasma followed by coprecipitation of the drug with calcium phosphate and removal of excess calcium ions by AG 50W-X8 resin. Plasma obtained in lower-dose clinical studies is treated by Method B, a more sensitive method using 10 ml of plasma, which is based on solid-phase extraction using a Sep-Pak C18 cartridge coupled with Method A. Urine and bone are treated similarly to Method B. The chromatographic system consists of a mobile phase at pH 11, an alkali-stable column and an electrochemical detector operating in the oxidation mode. The determination limit is 5 ng/ml for Method A and 0.5 ng/ml for Method B in plasma, 1 ng/ml in urine, and 25 ng/g in bone.

Animals↗
PubMed1992

Propolypeptide and mature portions of von Willebrand factor of bovine origin recognize different sites on type-I collagen obtained from bovine tendon.

We compared the binding of propolypeptide and mature portions of von Willebrand factor of bovine origin to fibrillar type-I collagen obtained from bovine tendon. The propolypeptide (pp-vWF) and the mature portion (m-vWF) of human origin consist of 741 and 2050 amino acids, respectively, and are rather large proteins. The collagen-binding properties of the two proteins of bovine origin were similar in that both bound more avidly to native collagen than to heat-denatured collagen. Bindings was affected similarly by ionic strength but was not modified either by divalent cations or a synthetic peptide containing Arg-Gly-Asp. However, the binding sites in the fibrillar type-I collagen molecule for pp-vWF and m-vWF seem to be different: the two proteins did not effectively compete with each other for binding to collagen. Furthermore, pepsin treatment of fibrillar type-I collagen resulted in a drastic decrease in the binding of pp-vWF, while only a moderate decrease in the binding of m-vWF was observed after the treatment.

Amino Acid Sequence↗
PubMed1992

Reconsideration of Bell's phenomenon using a magnetic search coil method.

The exact direction, amplitude and time course of Bell's phenomenon is still controversial. We evaluated the eye movements associated with spontaneous blinks, voluntary blinks and prolonged eyelid closure using a magnetic search coil method. Spontaneous blinks were accompanied by transient downward and nasalward eye movements, and similar movement accompanying voluntary blinks were often followed by upward movements. The eye positions occurring immediately after blinks often differed from the initial positions and were followed by corrective saccades, which disappeared when the subjects did not fixate. Prolonged eyelid closure was accompanied by tonic eye elevation and voluntary blinks were accompanied by marked transient eye elevation when eyelid closure was mechanically impeded. Under normal conditions Bell's phenomenon does not occur during blinks.

Adult↗
PubMed1992

Immunohistochemical demonstration of a new thiamine diphosphate-binding protein in the rat digestive tract.

We purified a new thiamine diphosphate-binding protein (ThDP-BP), produced an antiserum against it, and examined its immunohistochemical distribution in the rat gastrointestinal tract using the avidin-biotin complex method. Positive staining for ThDP-BP was found in the epithelial glands of the stomach, small intestine and large intestine, and in the nuclei of hepatocytes. Measurement of the content of thiamine and its phosphate esters in extracts from the gastric and intestinal mucosa also indicated the presence of ThDP-BP in the stomach and intestinal mucosa. ThDP-BP may be useful for investigating the absorption and metabolism of the thiamine in metabolic disorders.

Animals↗
PubMed1992

Factors affecting the outcome of patients with advanced urothelial cancer following chemotherapy with methotrexate, vinblastine, adriamycin, and cisplatin.

Attempts were made to identify factors related to the response of patients treated with intravenous methotrexate, vinblastine, Adriamycin, and cisplatin (M-VAC). The subjects consisted of 54 patients with advanced urothelial cancer whose histological type was transitional-cell carcinoma. The effects of various factors on the response were studied using univariate analysis and a multiple logistic regression model. The following factors were included in the analyses: (1) age, (2) sex, (3) performance status (PS), (4) primary site, (5) histological grade, (6) T category, (7) N category, (8) M category, (9) tumor status, and (10) dose of drugs. In all, 9 patients achieved a complete response and 23 showed a partial response, for an overall response rate of 59% (95% confidence limits, 46%-72%). Univariate analysis revealed that the PS, M category, and dose of drugs were related to the response, and there was a significant correlation among these three factors. In the multiple logistic regression model, the absolute value of t was high for the M category. The presence of distant metastases is an important factor in predicting poor efficacy for the present regimen. The management of metastatic disease will be the subject of further study in the treatment of advanced urothelial cancer.

Adult↗
PubMed1992

Enzymatic synthesis of p-nitrophenyl 4(5)-O-beta-D-galactosyl-alpha-maltopentaoside as a substrate for human alpha-amylases.

Enzymatic modification at the nonreducing end D-glucosyl residue of p-nitrophenyl alpha-maltopentaoside was developed by using the transglycosylation of beta-D-galactosidase from Bacillus circulans. The enzyme regioselectively synthesized p-nitrophenyl 4(5)-O-beta-D-galactosyl-alpha-maltopentaoside (a yield of 12.0% based on the amount of p-nitrophenyl alpha-maltopentaoside added) on a preparative scale from lactose as a donor and p-nitrophenyl alpha-maltopentaoside as an acceptor. It revealed that the nonreducing end galactosyl group of p-nitrophenyl 4(5)-O-beta-D-galactosyl-alpha-maltopentaoside did not prohibit the action of human salivary and pancreatic alpha-amylases. This derivative was shown to be very suitable as a novel substrate for analytical use of human alpha-amylase assay in serum through a conjugated reaction involving glucoamylase and alpha-D-glucosidase.

Amylases↗
PubMed1992

A modified technique for endoscopic mucosal resection of small early gastric carcinomas.

Endoscopic gastric mucosal resection (EGMR) is increasingly employed in early gastric cancer to remove the tumour with the surrounding mucosa and part of the submucosa after submucosal saline injection and staining to define the extent of the lesion. This study presents preliminary experience with a modified EGMR technique in five patients which allows more precise targeting and resection of the lesions. The time required for this procedure was less than 30 minutes in each case. All lesions were completely removed. In two patients, however, tumour growth invaded the submucosa and these patients therefore underwent subsequent surgery. Three patients with carcinoma confined to the mucosa were tumour-free at follow-up with repeat endoscopy and biopsy after 7 to 23 months.

Adenocarcinoma↗
PubMed1992

Diastolic mitral regurgitation in patients with first-degree atrioventricular block.

Diastolic mitral regurgitation has been observed in patients with DDD pacemakers when the atrioventricular (AV) delay was prolonged. However, diastolic mitral regurgitation associated with first-degree AV block has not been fully studied. We examined transmitral blood flow in 24 patients with first-degree AV block and normal cardiac function (ages 35.3 +/- 17.4 years), and in nine patients with DDD pacemakers and normal cardiac function (ages 73.1 +/- 8.1 years), using pulsed Doppler echocardiography. Diastolic mitral regurgitation was observed in 19 of 24 patients with first-degree AV block. Although PQ interval was shortened from 0.32 +/- 0.06 to 0.20 +/- 0.05 seconds (P < 0.01) after 1 mg atropine sulfate IV, the interval between P wave (ECG) and the beginning of diastolic mitral regurgitation did not change, while the duration of diastolic mitral regurgitation was shortened from 0.15 +/- 0.03 to 0.05 +/- 0.03 seconds (P < 0.01). There was a significant correlation between changes in PQ interval and changes in the duration of diastolic mitral regurgitation (r = 0.92, P < 0.001). Although cardiac output (3.9 +/- 0.05 L/min) and pulmonary capillary wedge pressure (5.1 +/- 1.5 mmHg) were normal in all patients with pacemakers, diastolic mitral regurgitation was observed when the AV delay was prolonged. The critical PQ interval for the appearance of diastolic mitral regurgitation was 0.23 +/- 0.01 seconds. In patients with prolonged PQ intervals, delayed ventricular contraction following atrial contraction may be associated with mitral regurgitation in the presence of a reversed AV pressure gradient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Finger blood flow in patients with low tension glaucoma and primary open-angle glaucoma.

Finger blood flow was studied by means of laser Doppler flowmetry in 12 patients with low tension glaucoma (LTG), 12 patients with primary open-angle glaucoma (POAG) and 12 normal subjects. Baseline flow, flow after immersion of the hand in warm water (+40 degrees C), and flow after exposure of the hand in cold water (+4 degrees C) were measured. Statistically significant differences were not found in each flow between the three groups of the patients (p greater than 0.05). Vasospastic response to warm and cold water was observed in 25% of LTG patients, 17% of POAG patients, and 25% of normal subjects. There was no significant difference between LTG, POAG, and normal subjects in finger blood flow.

Adult↗
PubMed1992

Simple method for measuring the antibiotic concentration required to kill adherent bacteria.

A simple method was developed for measuring the antibiotic susceptibility of bacteria adherent to plastic surfaces. Staphylococcus aureus cells adhered to the bottom of a 96-well plastic tissue culture plate were incubated in serially diluted antibiotic solutions. After a 24-hour-incubation the solutions were removed, and fresh medium without antibiotics was added to each well. The viability of the cells was judged by their growth after a further 24-hour-incubation. The antibiotic concentration required to kill adherent bacteria was far higher than that required for planktonic cells, although we used bactericidal drugs; beta-lactam, quinolone, and aminoglycoside antibiotics. The tolerance demonstrated by adherent cells is likely to play a role in the difficulties encountered in the chemotherapy of biofilm infections.

Anti-Bacterial Agents↗
PubMed1992

Ischemic optic neuropathy in a female carrier with Fabry's disease.

We report ocular findings of a patient with anterior ischemic optic neuropathy (AION) and cilioretinal artery occlusion in a female carrier of Fabry's disease. Fluorescein angiography revealed delayed filling of the upper and temporal part of peripapillary choroidal vessels and capillaries of the right optic disk and late filling of the cilioretinal artery. CT scanning was performed several times in early stages and demonstrated thickening of the intraorbital optic nerve due to ischemic edema. About 5 months later, the fellow eye showed optic disk edema, an early sign of AION, and was treated by systemic corticosteroid and urokinase whereby AION did not progress.

Adult↗
PubMed1992

Difference of spatial summation property between b and d waves in focal electroretinogram of the cat.

A new system for focal electroretinogram (ERG) using a charge-coupled device camera was developed. With this device, focal ERGs to on-off luminance modulation of uniform fields with different area (circle diameter; 16, 12, 8, 6 and 3 degrees) centered on the area centralis were recorded in 12 eyes of 6 cats. With a decrease of the stimulus area, the reduction of the amplitude in both b and d waves was observed, however, the implicit times of these waves were almost same. The amplitude ratio (12 degrees stimulus/16 degrees stimulus, 8/16, 6/16, and 3/16) of b and d waves showed statistically significant differences between the b wave and d wave (8/16, 6/16 and 3/16; p < 0.01). The difference in spatial summation property was demonstrated between the b wave and the d wave.

Animals↗
PubMed1992

Usefulness of ophthalmic examination in postnatal observation in teratology studies.

Pregnant rats were irradiated with soft x-ray at a dose of 635 r or 1270 r on Day 9 or 11 of gestation. The eyes of F1 offspring were examined by indirect ophthalmoscopy and slit lamp biomicroscopy in postnatal weeks 3 to 7. Ophthalmoscopic examination of offspring irradiated at a dose of 635r or 1270r on Gestational Day 9 revealed iris and choroidal coloboma together with microphthalmia and anophthalmia at Postnatal Week 3 or later. Choroidal coloboma, an anomaly that cannot be detected by the common external observation method, was found ophthalmoscopically in one rat without any external ocular abnormalities. This fact suggests that ophthalmoscopy in postnatal observation can be useful to detect ocular teratogenic potential of test compounds in preclinical safety studies.

Abnormalities, Radiation-Induced↗
PubMed1992

[Prophylactic effect of UFT in combination with intravesical chemotherapy on the recurrence of superficial bladder tumor].

The influence of N1-(2-tetrahydrofuryl)-5-fluorouracil plus uracil (UFT) on the recurrence of superficial bladder tumors was evaluated in a randomized clinical study. Group A (n = 196) underwent transurethral resection (TUR) and the intravesical chemoprophylaxis, while group B (n = 193) received 400 mg per a day of UFT orally for 6 months in addition to the instillation therapy. These adjuvant therapy was started one week after TUR. Consequently, 30 patients in group B showed UFT-related toxicity and administration of UFT was discontinued in 10 of them. In addition, 87 patients in group B did not complete the 6-month course of UFT administration. Comparison of 2-year actuarial non-recurrence curves revealed no significant difference between groups A and B. However, UFT seemed to have a favorable prophylactic effect when recurrence rates were compared among those patients with recurrent tumors (generalized Wilcoxon: p = 0.1277), and those with recurrent multiple tumors (p = 0.0847).

Administration, Intravesical↗
PubMed1992

Effects of repetitive administration of recombinant human interleukin-1 beta, an analog or corticotropin-releasing hormone combined with lysine vasopressin on rats with glucocorticoid-induced secondary adrenocortical insufficiency.

We investigated effects of corticotropin-releasing hormone (CRH), lysine vasopressin and interleukin (IL)-1 beta[1-148], a less pyrogenic analog of human IL-1 beta, on the hypothalamo-pituitary-adrenal axis in a rat model of secondary adrenocortical insufficiency. After 2 weeks of corticosterone 21-sodium succinate treatment, hypothalamic CRH, anterior pituitary adrenocorticotropic hormone (ACTH) and the adrenal weight of the rats decreased significantly and their plasma ACTH showed a significantly smaller response to ether stress, as did plasma corticosterone level. A mixed solution of CRH (10 micrograms) and lysine vasopressin (2 micrograms) or recombinant human IL-1 beta[1-148] (1 micrograms), administered to these rats for 7 days, apparently accelerated the recovery of the pituitary and adrenocortical responsiveness to ether stress and significantly increased the recovery rate of anterior pituitary ACTH contents and adrenal weight. The IL-1 beta analog also increased hypothalamic CRH. These data indicated that, in a rat model with glucocorticoid-induced adrenocortical insufficiency, synthesis and release of hypothalamic CRH, pituitary ACTH and adrenal glucocorticoid were all considerably affected. CRH combined with lysine vasopressin or a less pyrogenic IL-1 beta analog, when administered to these rats, accelerated the recovery of the pituitary and the adrenocortical functions significantly, suggesting the potential clinical usefulness of these peptides.

Adrenal Insufficiency↗
PubMed1992

[Evaluation and selection of normal range calculation methods].

There are many methods for normal range calculation, and they give different values even with the same normal data sample. I proposed three parameters, accuracy, precision and robustness, for evaluating the calculation methods. A complicated calculation method, the distribution selection method, seems to be theoretically correct, but it shows unstable precision and inadequate robustness when the normal data contain a small amount of abnormal data. A method called "Clinical reference range program (CRRP)" is a robust method, and is applicable to the data which contains abnormal data. I also proposed a condition which defines the sample size required for the calculation using the precision parameter.

Algorithms↗