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Biomedical subjects

T Aoki

Publications and source records attributed to T Aoki.

At least 721 records · Page 40Linked to original sources
PubMed1993

Pituitary carcinoma of pars distalis as a common neoplasm in Fischer-344 rats.

The incidence of invasive spontaneous pituitary carcinomas in Fischer-344 rats were studied. The pituitaries were examined histopathologically together with surrounding tissues including sphenoid bone. The incidence of carcinoma was higher than that previously reported in Fischer-344 rats. All the carcinomas observed in this study showed evidence of local invasion either ventrally into bone and bone marrow or laterally into peripheral nerves and blood vessels. No dorsal infiltration into the brain was recognized. Pituitary carcinoma with local invasion is a relatively common neoplasm when examined histopathologically together with the surrounding tissues.

Adenocarcinoma↗
PubMed1993

Human colorectal carcinoma-specific glycoconjugates detected by pokeweed mitogen lectin.

Pokeweed mitogen (PWM) lectin, known to bind branched poly-N-acetyllactosamines, has a highly selective affinity for human colorectal carcinomas. We performed light microscopic (LM) histochemistry with PWM lectin on paraffin sections of human colorectal tissues. In histological sections, normal mucosae and adenomas with mild dysplasia exhibited negative reaction (0/10, 0/13, respectively) with or without neuraminidase pre-digestion, whereas adenomas with moderate dysplasia showed a small increase in PWM lectin reactivity after neuraminidase digestion (4/23). In contrast, we observed a high incidence of positive reactivity in colorectal carcinoma without neuraminidase pre-digestion (38/44). After digestion with neuraminidase, there was increased reactivity of colorectal carcinomas in situ (7/12) and invasive carcinomas (13/32). These results imply that human colorectal carcinomas consistently contain substantial amounts of PWM-reactive branched poly-N-acetyllactosamine glycoconjugates structures. We also compared the staining patterns of PWM lectin and monoclonal antibodies (MAb) directed to Lewis X (LeX) or Lewis Y (LeY) antigen. PWM lectin reactivity was largely confined to the apical membranes of carcinoma tissues. MAb-LeX or MAb-LeY immunoreactivity was seen on the apical membranes and in the cytoplasm of both adenomas and carcinomas. Therefore, histochemical studies with this lectin should be useful for identification of carcinoma tissues and analysis of glycoconjugates associated with colorectal carcinoma.

Adenoma↗
PubMed1993

Detection of tetracycline resistance protein encoded by Bacillus subtilis plasmid pNS1.

Tetracycline resistance protein (TET) of Bacillus subtilis plasmid pNS1 was detected by immunoblot analysis using a specific antibody to TET-chloramphenicol acetyltransferase (CAT) fusion protein. In two-dimensional electrophoresis, one major spot which seemed to be the pNS1-encoded TET (pNS1-TET), was detected by immunostaining. Its molecular weight and isoelectric point were approximately 52 kDa and 6.2, respectively. Judging from the nucleotide sequence, the pNS1-TET is a very hydrophobic, 50 kDa protein. Therefore, the 52 kDa protein is thought to be an intact form of the pNS1-TET produced by B. subtilis cells.

Antibodies, Monoclonal↗
PubMed1993

Does hypertension or aging modulate directional shortening of the left ventricular midwall?

It is unclear whether aging or hypertension modulates directional contractile function of the left ventricular (LV) wall. We investigated LV midwall shortening and thickening in 35 normal subjects and in 15 patients with mild-to-moderate systemic hypertension (HT) using 2-dimensional echocardiography. The normal subjects were divided into 3 subgroups according to age: 13 subjects below 30 years, 12 subjects over 31 and below 59 years, and 10 subjects over 60 years. In normal subjects of all ages, no significant difference was observed between meridional shortening (%Lm = 16.3 +/- 2.4) and circumferential shortening (%Lc = 17.1 +/- 4.0), and a significant increase in the short-axis cross-sectional area (CSA) of the LV wall at end-systole was observed (p < 0.001). No significant differences with age were found in the measurements, except that %Lc/%Lm was reduced (p < 0.05) in the elderly subgroup. In HT, all measured parameters, i.e., %Lm, %Lc, %Lc/%Lm, wall thickening, and the change in CSA, showed no difference from those of normal subjects. We conclude that the shortening of the normal LV midwall is similar in both meridional and circumferential directions, and that aging and mild-to-moderate HT do not significantly affect this characteristic, when echocardiographic measurements are taken at rest at end-diastole and end-systole. This observation may be applied to simulation analyses of basic LV mechanics, such as the finite element method.

Adolescent↗
PubMed1993

Ischemic heart disease showing unusual angiographic findings.

Atherosclerotic lesions usually occur in the proximal and middle portion of the coronary arteries. Multiple obstructive lesions appearing only in the peripheral branches without lesions in the proximal or distal portion have not been reported. We encountered a patient with ischemic heart disease showing multiple obstruction in the peripheral branches of the right and left coronary arteries without significant stenotic lesions in the proximal or middle portion. This 49-year-old male was admitted to Yamada Red Cross Hospital due to angina pectoris. Coronary risk factors for him included hypertension, abnormal glucose tolerance, smoking habit, and obesity. Laboratory studies showed a complete blood count and normal blood chemistries, as well as thromboplastin and prothrombin times. Coronary angiography showed multiple obstruction or marked stenosis in the distal portion and peripheral branches; there was no stenosis in the proximal and middle portions. Left ventriculography showed severe hypokinesis in the diaphragmatic segment. Biopsy of the left ventricular endocardium showed interstitial fibrosis but showed no abnormalities in the myocardial fibers or cell infiltration to perivascular areas and vascular walls. Coronary angiography after two months showed multiple lesions, as previously observed. Although ischemic heart disease is caused by various types of vasculitis, embolism, coronary spasm, and fibromuscular dysplasia, in this patient, there were no findings suggestive of causes other than atherosclerosis. This case is interesting in terms of rare angiographic findings and its cause.

Coronary Angiography↗
PubMed1993

A case of dilated cardiomyopathy manifested by exercise-induced left bundle branch block.

We report an extremely rare case of dilated cardiomyopathy manifested by exercise-induced left bundle branch block. A 63-year-old female came to our hospital because supraventricular arrhythmia had been detected at a check-up. A treadmill exercise test induced left bundle branch block. However, chest X-ray and echocardiography revealed no abnormal finding. Two years later, the patient experienced exertional dyspnea. A chest X-ray examination showed cardiomegaly, and echocardiography showed a moderate impairment of left ventricular function with left ventricular dilatation. The diagnosis of dilated cardiomyopathy was made by left ventricular myocardial biopsy. No previous cases have initially shown exercise-induced left bundle branch block which was followed by left ventricular dysfunction due to dilated cardiomyopathy. Careful long-term observation of the clinical course is necessary in patients with exercise-induced left bundle branch block which shows no significant underlying disease.

Bundle-Branch Block↗
PubMed1993

[Effects of various histamine H2-receptor antagonists on gastrointestinal motility and gastric emptying].

Effects of various histamine H2-receptor antagonists (H2-RA) on gastrointestinal motility and gastric emptying were investigated. Ranitidine, nizatidine and cimetidine dose dependently induced contractions over the entire gastrointestinal tract, and the order of their effects was ranitidine > nizatidine > cimetidine. Roxatidine or famotidine had no effects on motility of the gastrointestinal tract. Ranitidine and nizatidine also induced contractions during the postprandial period and facilitated gastric emptying, while cimetidine, roxatidine or famotidine did not influence gastric emptying. Since acid reduction is thought to be the most important element of the treatment of peptic ulcer and reflux esophagitis, it was inferred that administration of a H2-RA selected with consideration of its property of facilitating gastrointestinal motility is effective in the treatment of patients with abnormal gastrointestinal motility.

Animals↗
PubMed1993

Changes in gastric hormones associated with gastric outlet obstruction. An experimental study in rats.

To determine the effect of persistent narrowing of the gastric outlet on peptic ulcer disease, changes in gastric hormones induced by pyloric stenosis were studied in an experimental model in the rat. Pyloric stenosis was created by constricting the pylorus to a 4-mm channel. Changes in serum gastrin and plasma somatostatin concentrations, in the length of the lesser curvature, in the size of the fundic and pyloric regions, and in the G-cell and D-cell counts were determined after 4 and 8 weeks (PS4W and PS8W) and compared with those of control groups. The size of the stomach, the serum gastrin concentration, and the corrected G-cell count (indexed to stomach size) were greater in PS8W than in PS4W rats, and both were greater than in respective controls (p < 0.005). Serum somatostatin concentrations were not different, but the total D-cell count and the corrected D-cell count were higher in PS4W and PS8W rats than in controls. Moreover, the total D-cell count and the corrected D-cell count were greater in PS8W than in PS4W (p < 0.05, p < 0.005).

Animals↗
PubMed1993

Bronchial hyperresponsiveness changes after 5 months of regular procaterol inhalation therapy in asthmatic children.

It is well known that procaterol has more potent antiallergic properties than previous beta-stimulants. Thirteen children with asthma who could be controlled for 2 months with a regular procaterol aerosol given 4 times/day (10 micrograms/dose) were studied. Histamine challenges were performed before and an average of 5 months after the consecutive treatment. No significant differences were seen in peak expiratory flow values. PC20 increased significantly from 132.9 +/- 127.7 micrograms/ml to 762.4 +/- 1205.7 micrograms/ml after 5 months. These results suggest that asthmatic children who can be controlled with regular use of the beta-stimulant procaterol are likely to have a decreased bronchial hyperresponsiveness.

Administration, Inhalation↗
PubMed1993

[The differences in role expectations of adolescent men and women for various others].

Everyday discourse patterns of adolescents were examined to clarify differences in their implicit expectations for various other people. Subjects were asked to complete 50 questionnaires on self-disclosing behaviors (Study 1) and which person in whom they would talk (Study 2) in everyday life. In both studies importance about each question is also scored by seven point scale. Total preferred percentage was calculated about each selected person. The results were as follows: same-sex friends were most frequently chosen as the person, to talk to while parents were selected for more important matters. Males comparatively tended to choose their father, while females their mother, to talk important matters with. Males had a tendency to talk about only important matters, while females tended to ignore importance. Males had a tendency to talk with girl friends about things they told no one else, while females tended to share with same-sex friends the same information as with boy friends. Gender differences in implicit role expectations for various others were discussed.

Adolescent↗
PubMed1993

[Interaction between vecuronium and pancuronium].

Interaction between vecuronium bromide (VB) and pancuronium bromide (PB) with regard to a change in duration of action was investigated in 32 elective surgical patients divided into four groups. Initial and supplemental drugs were as follow; group I: VB-->VB, group II: PB-->VB, group III: VB-->PB, group IV: PB-->PB. The muscle response was quantified electromyographically. Anesthesia was induced with thiopental. VB or PB 0.08 mg.kg-1 (initial dose) was given to facilitate endotracheal intubation. Anesthesia was maintained with 66% nitrous oxide and 2% sevoflurane in oxygen. Supplemental dose (0.015 mg.kg-1) of the muscle relaxants was administered at 10% recovery of twitch height. Duration of action was defined as the interval between administration and 10% recovery. Duration of action of supplemental doses of VB was significantly longer in group II than in group I. That of PB was significantly shorter in group III than in group IV. Therefore, it should be noticed that duration of action of supplemental relaxant is largely modified by the initial one.

Adult↗
PubMed1993

[A comparison of two delivery devices on the bronchodilatory effects of procaterol from a metered dose inhaler].

The bronchodilatory response to procaterol delivery by a metered dose inhaler with a spacer device (Volumatic) and a corniced extension tube was studied in a double blind manner in 18 asthmatic children, who were brought to our emergency room with acute attacks. The mean percent increase in forced expiratory volume in 1 second (FEV1) with the Volumatic was 55.6 +/- 39.3%, and 46.2 +/- 37.4% with the extension tube. There were no significant differences in the mean percent increase in FEV1, forced vital capacity (FVC), maximal flow rate at 50% of vital capacity (V50), maximal flow rate at 25% of vital capacity (V25) and peak expiratory flow rate (PEFR) between the two devices. It is concluded that there is no difference in the bronchodilatory effects of the two devices. The corniced extension tube has the advantage of being less expensive and more convenient to carry around.

Acute Disease↗
PubMed1993

Cloning and sequence analysis of the major cysteine protease expressed in the trematode parasite Fasciola sp.

A cDNA encoding the Fasciola cysteine protease precursor has been cloned and sequenced. The deduced precursor contains 325 amino acid residues (M(r) 36,768) consisting of a signal sequence (pre-region, 15 residues), pro-region (90 residues), and mature protease (220 residues, M(r) 24,371). Cys27, His164, and Asn184 form the catalytic triad in the active site of the mature enzyme, and their adjacent regions are highly conserved. The parasite enzyme showed 50, 44, and 27% amino acid sequence homologies, compared with mammalian lysosomal cathepsins L, H, and B, respectively. N-linked glycosylation sites which are thought to be targeting signals for cathepsins into lysosomes is absent in any region of the Fasciola protease precursor.

Amino Acid Sequence↗
PubMed1993

[Two cases of intralobar pulmonary sequestration--demonstration of the aberrant artery by magnetic resonance imaging].

Diagnosis of intralobar pulmonary sequestration has required demonstration of systemic blood supply by arteriography. We report two cases in which retrocardiac abnormal shadows were observed on chest radiographs and aberrant arteries arising from the descending aorta toward the sequestrum were demonstrated by magnetic resonance imaging (MRI). The sequestra were observed as high intensity area suggesting cystic lesions on T2-weighted MRI. In both cases, the sequestra were excised and aberrant arteries (5 mm and 10 mm in diameter) arising from the aorta were recognized at surgery. Both cases were diagnosed as intralobar sequestrations histopathologically. MRI is a safe noninvasive alternative for diagnosis of pulmonary sequestration instead of arteriography in some cases with a larger aberrant artery.

Adult↗
PubMed1993

Effect of nicotine on cognitive disturbance in animals with acetylcholine deficient brain.

The effect of nicotine on learning disturbance was tested in rats fed with a choline-deficient diet (Ch free) or in senescence-accelerated mice (SAM). Concentration of acetylcholine in the brain was significantly lower in rats fed with Ch free and SAM. Passive avoidance learning shows that rats fed with Ch free and SAM showed significantly impaired learning, compared to controls. Nicotine (0.04 mg/kg) administered intraperitonealy significantly improved learning in animals with learning disturbances, as well as in controls. Vitamin B12 facilitated acetylcholine synthesis or release in the brain and improved the cognitive disturbance. We therefore suggest that acetylcholine contributes to learning and that nicotine may improve learning in an acetylcholine deprived rats.

Acetylcholine↗