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Biomedical subjects

A Itoh

Publications and source records attributed to A Itoh.

At least 163 records · Page 9Linked to original sources
PubMed1994

Tissue specificity of mitochondrial F0F1-ATPase activity of Lilium longiflorum plant.

A large difference was found in the activities of oligomycin-sensitive mitochondrial F0F1-ATPase isolated from different tissues of Lilium longiflorum plants. The enzyme activity of F0F1-ATPase in pollen was the highest, while that in bulbs was the lowest. When ATPases were cross-reconstituted from F1-ATPases and F1-depleted submitochondrial particles (SMP), ATPases reconstituted from F1-depleted pollen SMP showed the higher activity regardless of the source of F1-ATPase. Fatty acid compositions of phospholipids in SMP were also different between bulbs and pollen. These suggest that the F0 portion and/or its environment are important for regulation of F0F1-ATPase activity in L. longiflorum plant.

Enzyme-Linked Immunosorbent Assay↗
PubMed1994

Ischemia-induced changes in catecholamine release and their mechanisms: a study using cultured bovine adrenal chromaffin cells.

Ischemia-induced changes in neurotransmitter release and their mechanisms were examined using cultured bovine adrenal chromaffin cells. When the cells were incubated in glucose-free media equilibrated with 0% O2/100% N2 (ischemia), ATP content decreased and reached the minimum level within 40 min. Control incubation was done in media equilibrated with 21% O2 in N2. After 10-min incubation under ischemic conditions, basal catecholamine (CA) release was elevated and the elevation persisted up to 90 min. High K(+)-evoked CA release was transiently enhanced at 10 min, but after that, it decreased to reach the minimum level at 60 min. At 10 min, cytosolic free Ca2+ concentration ([Ca2+]i) and 45Ca2+ uptake of the resting cells (basal values) and high K(+)-evoked increases in these two parameters were unchanged, but CA release from permeabilized cells in response to Ca2+ in media was augmented. After 60-min incubation under ischemic conditions, basal [Ca2+]i was elevated: the elevation was observed even in the absence of extracellular Ca2+. In contrast, high K(+)-evoked increases in [Ca2+]i and in 45Ca2+ uptake were suppressed, but basal 45Ca2+ uptake into intact cells and CA release from permeabilized cells were unchanged. These results suggest that in an early phase (10 min) of ischemia, both basal and stimulation-evoked CA release are augmented because of increased sensitivity of exocytotic machinery to Ca2+. In the late phase (60 min), basal CA release is augmented because of an increase in basal [Ca2+]i, which is due to accumulation of Ca2+ derived from intracellular Ca2+ pools: stimulation-evoked CA release is suppressed because of inhibition of stimulation-evoked increase in [Ca2+]i, which is due to functional disturbance of voltage-dependent Ca2+ channels.

Adenosine Triphosphate↗
PubMed1994

beta-Amyloid protein-induced Alzheimer's disease animal model.

To investigate the toxicity of beta-amyloid protein which consisted of senile plaques of Alzheimer's disease (AD), this was infused into cerebral ventricle for 14 days by using mini-osmotic pump. The performance of the water maze task in beta-amyloid protein-treated rats was impaired. Choline acetyltransferase activity significantly decreased in the frontal cortex and hippocampus. These results suggest that the deposition of beta-amyloid protein in the brain is related to the impairment of learning and cholinergic neuronal degeneration, and that beta-amyloid protein-treated rats could be used as an animal model for AD.

Alzheimer Disease↗
PubMed1994

Histamine modulates three types of K+ current in a human intestinal epithelial cell line.

K+ conductance species in a human intestinal epithelial cell line (Intestine 407) were studied in connection with their sensitivities to an intestinal secretagogue, histamine, using the tight-seal whole-cell patch-clamp technique. Applications of positive command pulses rapidly induced outward K+ currents. The conductance became progressively larger with increasing command voltages, exhibiting an outwardly rectifying current voltage relation. Inward K+ currents were also rapidly activated upon applications of hyperpolarizing pulses at potentials negative to the equilibrium potential of K+ (EK), and the conductance inwardly rectified. Application of a Ca2+ ionophore, ionomycin, brought about activation of additional K+ currents. An inhibitor of protein kinase C, polymyxin B, did not affect the ionomycin-induced response. Histamine (10-200 microM) also activated a similar K+ current which was abolished by cytosolic Ca2+ chelation. Under conditions where Ca2+ mobilization was minimized, histamine was found to significantly augment inwardly rectifying K+, but suppress outwardly rectifying K+, currents. Polymyxin B blocked these effects of histamine. An activator of protein kinase C, 1-oleoyl-2-acetylglycerol, mimicked the histamine effects. It is concluded that the intestinal epithelial cell has three distinct types of K+ conductance and that histamine modulates not only Ca(2+)-activated K+ conductance via Ca2+ mobilization, but also inward- and outward-rectifier K+ conductances via activation of protein kinase C.

Calcium↗
PubMed1994

Effects of subacute administration of methamphetamine and nicotine on locomotor activity in transgenic mice expressing the human tyrosine hydroxylase gene.

We produced transgenic (Tg) mice carrying the human tyrosine hydroxylase (TH) gene. To investigate differences in the dopaminergic (DAergic) neuronal activity between the Tg and nTg mice, we examined changes in the locomotor activity induced by methamphetamine (MAP) and nicotine (NIC), which enhances DA release and induces TH enzyme activation, respectively. Surprisingly, however, the intensity of MAP (2.5 mg/kg, once a day for 14 days)-induced hyperlocomotion in the nTg mice was greater than that in the Tg mice, and, furthermore, the Tg mice were less sensitive to subacute administration of NIC (0.5 mg/kg, once a day for 14 days) than the nTg mice. These results suggest that DAergic neuronal function is suppressed in Tg mice to compensate for the overexpression of TH.

Animals↗
PubMed1994

Nicotine reverses scopolamine-induced impairment of performance in passive avoidance task in rats through its action on the dopaminergic neuronal system.

Interest has recently focused on tobacco and/or nicotine in relation to senile dementia of the Alzheimer type because the population of patients with this disease among tobacco smokers is significantly smaller than in nonsmokers. We investigated whether, in relation to the dopaminergic neuronal system, nicotine was effective in ameliorating the impairment of performance in passive avoidance tasks in rats induced by scopolamine, an inhibitor of muscarinic acetylcholine receptors. Scopolamine and nicotine were coadministered to rats 30 min before the acquisition trial. Some rats received scopolamine alone; they showed much shorter step-through latency (STL) than the control group in the retention test. Nicotine significantly prolonged the decreased STL induced by scopolamine. The effects of nicotine were inhibited by the preadministration of mecamylamine, SCH 23390, and (-)sulpiride, which are nicotinic acetylcholine, D1, and D2 receptor antagonists, respectively. These results suggest that nicotine, by activating the nicotinic acetylcholinergic and dopaminergic neuronal systems, ameliorates the impairment of performance in the passive avoidance task induced by a muscarinic acetylcholine receptor blocker.

Animals↗
PubMed1994

Preparation of agglomerated crystals for direct tabletting and microencapsulation by the spherical crystallization technique with a continuous system.

Adhesive and cohesive properties of chlorpromazine hydrochloride (CP) crystals were modified to improve their powder processing, e.g., direct tabletting and microencapsulation, by agglomeration. Moreover, sustained-released gelling microcapsules of CP were devised to prolong the pharmacological effect. The spherical crystallization technique was applied to prepare agglomerates for direct tabletting and microencapsulation to use them as core materials. The ethanolic solution dissolving CP was poured into a stirred cyclohexane, yielding spherically agglomerated crystals. The resultant agglomerates were free-flowing and easily packable spheres with average diameters of 200 to 1000 microns. The agglomerates reserved the high compressibility of the original powder having a small particle size (14 microns). The compression behavior represented by Heckel's equation suggested that the agglomerates were disintegrated to individual primary crystals at low compression pressures, and then they were closely repacked and plastically deformed at higher pressures. After agglomeration, microencapsulation was continuously performed in the same batch by a phase separation method. Coacervate droplets produced by pouring cyclohexane into a dichloromethane solution, dissolving polyvinyl acetate as a coating polymer, were added to the crystallization system under stirring, to prepare the microcapsules. By filling the microcapsules in gelatin hard capsules or tabletting them, their drug release rates became retarded compared with the physical mixture treated in the same way, having the same formulation as the microcapsules. This phenomenon was due to the gelation of polyvinyl acetate of the microcapsules in the dissolution medium, whose glass transition temperature is very low. This novel sustained-release dosage form is termed "gelled microcapsules."

Adhesiveness↗
PubMed1994

A seroepidemiological study of hepatitis C virus (HCV) in an area with a high prevalence of chronic liver disease in the Kyushu district of Japan.

The incidence of hepatitis virus type C (HCV) in an area, Futase, of Iizuka city in Chikuho province in the northeastern part of Fukuoka prefecture in Kyushu, Japan, was estimated by screening sera for anti-HCV antibodies. Titers of anti human T-lymphotropic virus type I (HTLV-I) antibodies and hepatitis virus type B surface antigens (HBs) were also determined. The area of the present study is known to have a particularly high prevalence of chronic liver diseases, because coal mining was the key industry until a few decades ago. Also, in the old days it was rather isolated from the neighboring vicinities by surrounding mountains. The subjects of the present survey were 310 patients (117 males and 193 females) with various chronic diseases who visited Futase Social Insurance Hospital during a two year period from 1991 to 1992. Anti-HCV antibodies were detected in the sera of 55 patients, which is an overall positive rate of 18% (26% in male and 14% in female patients). This is extremely high compared to an estimated nationwide average positive rate of 1.6%. Even in 270 patients with normal liver function, the incidence was as high as 10%. The incidences were particularly high in groups of patients aged 40 through 49, 50 through 59 and 60 through 69, ranging from 20 to 23%, while they were as low as 13 and 17% in those aged 70 through 79 and 80 through 89 years, respectively. A high incidence, 57% was estimated for the patients with impaired liver function due to chronic liver diseases, especially in those concomitantly having diabetes mellitus (DM), 91%. The incidence of anti-HCV antibodies was the highest, 100%, in patients having both liver cirrhosis (LC) and DM. This was followed by those having chronic hepatitis (CH) and DM concomitantly and by those with LC alone, 86% each, and by those with CH alone 44%. Furthermore, the genotypes of the HCV in the sera of nine randomly selected carrier patients who had anti-HCV antibodies, even though they had diseases other than hepatic diseases and their liver functions were normal, were examined by the polymerase chain reaction method employing type-specific primers for DNA amplification. As a result, all the HCV strains were type II. On the other hand, there were no apparent differences in the incidences of HTLV-I in the area of the present study and in neighboring provinces of the same prefecture, Fukuoka.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1994

Intraductal ultrasonography for the examination of duodenal papillary region.

The purpose of this study was to provide basic criteria for interpreting images of the normal duodenal papillary region obtained by intraductal ultrasonography at the frequency of 20 MHz. Our in vitro examination of autopsy specimens from 15 patients revealed that the images could be classified into three patterns according to the spatial relationships between the duodenal muscularis propria and the bile duct, or the common duct. Oddi's muscle was clearly demonstrated surrounding the mucosa of the bile duct or the common duct, which was visualized as a hypoechoic layer. The images obtained using in vivo examination of 60 patients with pancreato-biliary disease via either the percutaneous or the peroral approach were similar to the images obtained in vitro. In eight patients with cancer of the papilla of Vater, the tumor was demonstrated clearly on intraductal sonograms. The intraductal imaging features of the normal papillary region were clarified, and the clinical usefulness of this technique in the evaluation of the tumor extent in patients with cancer of the papilla of Vater is suggested.

Ampulla of Vater↗
PubMed1994

Deficiency of the fourth component of complement (C4): a family case.

In this report, an apparently healthy 38-year-old woman with a remarkably low serum C4 value is described together with other family members who had moderately low serum C4. Plasma C4 typing disclosed that the proband inherited two C4B "null" haplotypes. In addition, Southern blot analysis of the C4 gene indicated that the C4A gene was partially deleted on one of these two haplotypes in the proband. We thus concluded that a de novo deletion on the inherited half-null haplotype was the likeliest cause of the low C4 level.

Adult↗
PubMed1994

[Diagnosis of the pancreatic diseases by intraductal ultrasound of the pancreas--with special reference to clinical cases difficult to diagnose differentially pancreatic diseases by the endoscopic retrograde pancreatography].

We examined the usefulness of the intraductal ultrasound (IDUS) examinations by comparing the IDUS images with the endoscopic retrograde (ER) pancreatograms. We inserted an IDUS probe with 30 MHz at frequency transpapillary into the main pancreatic duct (MPD) in 105 cases with pancreatic diseases (30 cancers, 30 mucin-producing tumor, 3 islet cell tumor, 1 pancreatic serous cyst adenoma, 1 pancreatic teratoma, 1 pancreatic solid and cystic tumor and 39 chronic pancreatitis). All 105 cases were performed ER pancreatography. Sixty-four of 105 cases (22 cancers, 20 mucin-producing tumor, 3 islet cell tumor, 1 pancreatic serous cyst adenoma, 1 pancreatic teratoma, 1 pancreatic solid and cystic tumor and 16 chronic pancreatitis) were operated and the IDUS images were compared with the corresponding histopathological sections. The usefulness of the IDUS examinations of the pancreatic diseases were the following cases; differential diagnosis between benign and malignant cases with localized stenosis of the MPD, differential diagnosis of the cases with displacement of the MPD, and the diagnosis of the intraductal extent and of invasion of the tumor in the mucin-producing tumor of the pancreas with the dilation of the MPD. IDUS examinations are performed by the IDUS probe with high frequency, so the indications of the IDUS examinations are to detect the small lesions in the pancreas.

Cholangiopancreatography, Endoscopic Retrograde↗
PubMed1994

[Mucin-producing tumor of the pancreas: surgery or follow-up?].

Clinicopathological studies were carried out in 35 cases of mucin-producing tumor of the pancreas. In addition, natural history and serial pancreatogram changes were studied in 12 long-term follow-up cases. 83% of the main duct type and branch duct type greater than 4 cm were malignant, whereas hyperplasia cases were found in the branch duct type of 3 cm or less in size without marked dilation of the main duct and excrescent nodules. 33% of carcinoma cases were accompanied by parenchymal invasion and all those cases were of polypoid type of 2.5 cm or more in size. In long-term follow-up cases, all 3 cases of the main duct type showed progression of pancreatograms. In contrast, 8 of 9 cases of the branch duct type remained unchanged. These results suggest that surgical resection is mandatory in the main duct type and that the branch duct type where hyperplasia is highly suspected can be followed up.

Adenocarcinoma, Mucinous↗
PubMed1993

Correlation of GM-CSF mRNA in bronchoalveolar fluid with indices of clinical activity in sarcoidosis.

BACKGROUND: Granulocyte-macrophage colony stimulating factor (GM-CSF) has several proinflammatory effects, some of which potentially favour granuloma formation. Its mRNA expression by the inflammatory cells recovered from lungs of patients with pulmonary sarcoidosis has been previously reported. In this study an association between GM-CSF expression and manifestations of the disease was explored. METHODS: GM-CSF mRNA was detected by reverse transcription polymerase chain reaction in the cells of bronchoalveolar lavage (BAL) fluid of 20 patients with pulmonary sarcoidosis. RESULTS: GM-CSF mRNA expression was positive in 15 of 20 patients with sarcoidosis. Fourteen of the 15 patients with positive mRNA expression had worsening or unchanged disease during the year preceding this study, on the basis of radiographic or physical findings, or both, whereas all five "negative" patients were judged to be improving. Similarly, serum levels of angiotensin converting enzyme, the proportion of lymphocytes in BAL fluid, and the CD4+/CD8+ ratio of lymphocytes in BAL fluid were significantly higher in the positive patients. CONCLUSIONS: There was an association between the presence of GM-CSF mRNA in the cells in BAL fluid and other indices of disease activity in sarcoidosis.

Adult↗
PubMed1993

Factors relating to coagulation, fibrinolysis and hepatic damage after liver resection.

A survey of the blood of twenty-two patients who had undergone hepatic resection was performed. Serum levels of alpha-2 plasmin inhibitor-plasmin complex initially decreased from 1.58 +/- 0.31 microgram/ml on the preoperative day (PREOP), to 0.92 +/- 0.14 mu/ml on the first postoperative day (POD 1), and then increased to 3.13 +/- 0.92 micrograms/ml on the seventh postoperative day (POD 7) (mean +/- SE)). Thrombin-anti-thrombin III complex (14.2 +/- 4.3 ng/ml on PREOP and 26.0 +/- 4.1 ng/ml on POD 7 (mean +/- SE)) and D-dimer (335 +/- 96 ng/ml on PREOP and 1859 +/- 258 ng/ml on POD 7 (mean +/- SE)) increased in the early postoperative stage. The level of 6-keto-prostaglandin F1 alpha increased after the operations (from 13.2 +/- 1.8 pg/ml on PREOP to 37.8 +/- 12.8 pg/ml on POD 7 (mean +/- SE)). The level of thromboxane B-2 decreased at first, and then gradually increased and returned to its preoperative level on POD 7 (144.7 +/- 43.8 pg/ml on PREOP, 57.6 +/- 27.5 pg/ml on POD 1 and 152.5 +/- 58.4 pg/ml on POD 7 (mean +/- SE)). Superoxide dismutase activity increased at first, and then gradually decreased, postoperatively (2.8 +/- 0.5 NU/ml on PREOP, 4.8 +/- 0.8 NU/ml on POD 1 and 2.6 +/- 0.3 NU/ml on POD 7 (mean +/- SE)). That is, biodefensive reactions which protect patients against the shift to disseminated intravascular coagulation (DIC) were inferred with by the increase in antiplatelet aggregation, despite the activation of coagulation and fibrinolytic mechanisms after hepatic resection.

Adult↗