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Biomedical subjects

K Takeuchi

Publications and source records attributed to K Takeuchi.

At least 1,027 records · Page 57Linked to original sources
PubMed1988

Intracellular processing of mumps virus glycoproteins.

Using newly isolated monoclonal antibodies (MoAb) directed to the hemagglutinin-neuraminidase (HN) and the fusion (F) glycoproteins of mumps virus, we have analyzed post-translational modification of both glycoproteins. The HN glycoprotein synthesized as a monomer slowly acquires immunoreactivity with a monoclonal antibody (MoAb) to the HN in conjunction with the formation of oligomers. The oligomerization of the HN protein appeared to take place during transport of the protein through the Golgi apparatus. The immunoreactivity of the F protein evolved quickly in the rough endoplasmic reticulum, and the precursor of the F protein appeared to be proteolytically cleaved into F1 and F2 at the trans Golgi cisternae.

Animals↗
PubMed1988

Lithium increases dynorphin A(1-8) and prodynorphin mRNA levels in the basal ganglia of rats.

The aim of this study was to understand the possible influence of the antimanic drug, lithium, and the neuroleptic, haloperidol, alone or in combination, on the regulation of dynorphin biosynthesis in the striatum. The study was done using male Fisher-344 rats subjected to a regimen of subchronic administration of lithium chloride (4 mEq/kg/day for 1,2,4 or 6 days, i.p.) or a regimen of chronic oral administration of a diet containing lithium carbonate (1.5 g/kg of the diet). Subchronic administration of lithium increased striatal dynorphin A(1-8)-like immunoreactivity (DN-LI) in a time-related fashion. Immunocytochemistry revealed an increase in DN-LI in fibers and cells clustered in 'patches' throughout striatum. The increase in DN-LI was reversible on cessation of lithium administration. Concurrent administration of lithium and an opiate antagonist, naltrexone, or a dopamine receptor antagonist, haloperidol, did not influence the changes induced by lithium. Chronic oral administration of lithium for 21 days led to an increase in DN-LI in the striatum. Co-administration of haloperidol with the 21 day regimen of lithium administration failed to affect the increase in DN-LI. The prodynorphin mRNA abundance in the striatum was quantitated by a molecular hybridization procedure using a prodynorphin 32P-cRNA probe generated from the Riboprobe system. Evidence from the Northern blot analysis reveals that lithium increases the prodynorphin mRNA abundance in the striatum. These results indicate that lithium affects the dynamics of prodynorphin biosynthesis in the striatum, presumably increasing transcription and/or translational processes.

Animals↗
PubMed1988

Generation of multiple troponin T isoforms is a common feature of the muscles in various chordate animals.

1. Troponin T (TNT) expressed in various vertebrate skeletal and ascidian smooth muscles was examined by two-dimensional electrophoresis in combination with immunoblotting. 2. A monoclonal anti-TNT antibody, NT-302, exhibited binding ability to various TNT variants in the vertebrate and protochordate animals. 3. TNT isoform pattern differed among the animals, but the existence of multiple TNT isoforms in a single muscle tissue was the general feature of all the animals examined.

Animals↗
PubMed1988

Necessity for ICP monitoring to supplement GCS in head trauma cases.

The necessity for ICP monitoring together with GCS findings to detect deterioration in head trauma cases and determine the treatment required was studied. There were 18 subjects (14 males, 4 females) aged from 11 to 61. Cases of primary brain stem damage were excluded. Eight cases had GCS of 6-10, and 10 cases scores of 11-15. Initial CTs of these cases indicated the following conditions: thin acute extradural haematoma (A-EDH), thin acute subdural haematoma (A-SDH), brain contusion, and single or multiple intracerebral haematoma (ICH). However, in no case was any mass effect clearly shown. Medical decompression (osmotherapy, barbiturate, steroid and mechanical hyperventilation) was carried out with simultaneous ICP monitoring. Based upon our cases which showed a GCS score of 10 or less, ICP monitoring should accompany medical decompression. Where the ICP cannot be maintained below 20 mm Hg, there is a high risk (about 60%) of haematoma enlargement, delayed haematoma, or increasing brain oedema. ICP monitoring in these cases should be maintained for at least one week. Timely surgical decompression is necessary when the ICP stays above 20 mm Hg, the GCS score drops below 10, and repeat CT scan indicates progress of the mass effect.

Adolescent↗
PubMed1988

Hereditary hemorrhagic telangiectasia with growing pulmonary arteriovenous fistulas followed for 24 years.

A 47-year-old man was admitted for follow-up of an abnormal chest x-ray. He had a history of epistaxis and a brain abscess and a family history of pulmonary arteriovenous fistulas. Physical examination showed clubbed fingers and telangiectasia of the tongue. Laboratory data revealed evidence of polycythemia and hypoxia. Contrast echocardiography and pulmonary perfusion scintigraphy were suggestive of a right-to-left shunt. From the oxygen tension and content of blood taken at cardiac catheterization, the shunt ratio was calculated to be 57.8%. Multiple bilateral pulmonary arteriovenous fistulas were confirmed by angiography, and the patient was diagnosed as having hereditary hemorrhagic telangiectasia. A review of x-ray films taken over a 24-year period demonstrated that the fistulas in both lungs had been increasing gradually in size at different rates. A right lower lobectomy relieved the hypoxia, but the patient died unexpectedly on the twelfth postoperative day. There was no evidence of fistula rupture on chest film, but no autopsy was performed.

Arteriovenous Fistula↗
PubMed1988

Effects of water-immersion restraint stress on rat gastric epithelial cell loss and migration.

The effect of water-immersion restraint stress on cell loss and migration was studied in rats. In order to label the proliferating cells, tritiated thymidine was injected 72 h prior to the stress. Histoautoradiography was prepared for the measurement of cell migration and residual mucosal DNA-bound radioactivity by means of liquid scintillation count for cell loss. Residual DNA-bound radioactivity was significantly decreased in fundic mucosa, but not in antral mucosa, after 60-90 min of water-immersion restraint stress. Cell migration was also found to be accelerated in fundic mucosa after 90 min of stress. These results indicate that water-immersion restraint stress results in an increase of cell loss, which is accompanied by compensated acceleration of cell migration, in fundic mucosa of rats before the development of gastric erosions. In view of the previous observation that stress for the same short-term duration inhibits fundic epithelial proliferation in rats, this combination, increased cell loss with depressed epithelial proliferation, may contribute to stress-related gastric mucosal lesions in rats.

Animals↗
PubMed1988

Papillary collecting tubule responsiveness to vasoactive hormones in spontaneously hypertensive rats.

Renal papillary collecting tubule (RPCT) hormone responsiveness was compared between cultured RPCT cells from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY). Unstimulated cells from 4-week-old SHR produced less prostaglandin E2 (PGE2) and cyclic (c)AMP than comparable cells from WKY, while cells from both stains synthesized similar amounts of PGE2 after stimulation with arachidonate, A23187 or bradykinin and similar amounts of cAMP after stimulation with vasopressin or PGE2. There was no difference in basal or stimulated levels of cyclic (c)GMP between the strains. In RPCT cells from 16-week-old rats, basal levels of cAMP, cGMP and PGE2 were significantly lower than those from 4-week-old rats, but they did not differ between the strains. These results suggest that RPCT cells of SHR and WKY at the post-weaning period may differ in the metabolism of PGE2 and cAMP. This difference may be attributed to the possible defect in arachidonate availability in SHR.

Age Factors↗
PubMed1988

Molecular cloning and sequence analysis of the mumps virus gene encoding the P protein: mumps virus P gene is monocistronic.

The nucleotide sequence of the P (phosphoprotein) gene of two strains of mumps virus has been determined from overlapping cDNA clones. The P gene contained a single open reading frame coding for a protein of 391 amino acids with a calculated Mr of 41,587, in good agreement with the value (40K to 45K) estimated from electrophoretic mobility on SDS-polyacrylamide gels. No open reading frame analogous to the C gene of other paramyxoviruses existed in the mumps virus P gene region. Comparison of the amino acid sequence of the mumps virus P protein with that of Newcastle disease virus showed a limited sequence homology.

Amino Acid Sequence↗
PubMed1988

Duodenal ulcers induced by indomethacin plus histamine in the dog. Involvement of the impaired duodenal alkaline secretion in their pathogenesis.

Mongrel dogs of either sex, weighing 14.0 +/- 0.7 kg, were given indomethacin orally in a dose of 70 mg/dog, and they were deprived of food thereafter. Twelve hours later, the animals were given histamine-2HCl intramuscularly 4 times every hour in a dose of 40 or 80 micrograms/kg. Indomethacin followed by histamine treatment produced well-defined ulcers in the proximal duodenum within 18 h with a few lesions in the stomach, although either of these agents alone did not induce any damage in the mucosa. Both the severity and incidence of the duodenal lesions were increased dose-dependently by histamine; the lesion index was 38.8 +/- 8.4 mm2 (n = 7) with an incidence of 100% at the dose of 80 micrograms/kg of histamine. The duodenal lesions mostly consisted of 2-4 round or elongated lesions which penetrated to the muscularis mucosae in some cases (42.8%). Histamine caused a marked increase in acid secretion in dogs with a vagally innervated total pouch, while indomethacin significantly inhibited the increased alkaline secretion caused by acid (50 mM HCl for 10 min) in the duodenal pouch (10 cm distal to the pylorus). Both cimetidine (20 mg/kg) and 16,16-dimethyl prostaglandin E2 (3 micrograms/kg), given subcutaneously, prevented these lesions in the duodenum as well as in the stomach by inhibiting acid secretion and/or increasing duodenal alkaline secretion. These results suggest that (a) indomethacin consistently produced ulcers in the duodenum of the dog when acid hypersecretion was induced by histamine, and (b) an impaired duodenal alkaline secretion may be an important pathogenetic element in this model.

Acid-Base Equilibrium↗
PubMed1988

Repair of mucosal damage induced by ethanol in the rat stomach. Effects of concentration, exposure period and prostaglandins.

We investigated the relationship between the severity of acute injury and the rapidity of mucosal repair in stomachs of anesthetized rats, and examined the influence of prostaglandins (PGs) on the process of restoration. Different degrees of mucosal damage were produced using ethanol and by varying the concentration (5-100%) and the exposure period (1-60 min). Exposure of the stomach for 10 min to ethanol induced hemorrhagic lesions and a reduction in the transmucosal potential difference (PD); its severity and its magnitude were increased in a concentration-related manner. After removal of ethanol, the reduced PD recovered quickly in the case of 5-25% ethanol, but it normalized slowly or did not show any recovery in the case of 50 or 100% ethanol, respectively. Histologically, ethanol at 5-25% produced various degrees of damage in the superficial epithelial cells, while the damage was deeper into the mucosa beyond the basal lamina after exposure to ethanol at 50% or greater. Similar phenomena were observed after exposure to 50% ethanol for various periods; the rapidity of PD recovery and mucosal restoration was faster when the exposure period was less than 2 min, and these parameters became slower as it was increased. Moreover, the PD recovery was significantly expedited or delayed, respectively, by 16,16-dimethyl PGE2 (30 micrograms/kg) or indomethacin (5 mg/kg), and the former counteracted the inhibitory effect of indomethacin. These results suggest that the process of mucosal regeneration may largely depend on the severity of damage initially formed, and probably involves factors sensitive to endogenous PGs.

Administration, Cutaneous↗
PubMed1988

Relationship between cardiac function and the sympathetic nervous system during exercise in patients with essential hypertension.

The relationship between echographical cardiac function and sympathetic nerve activity during dynamic exercise was examined in patients with essential hypertension. Nine normotensives (Group N), 11 hypertensive patients without cardiac hypertrophy (Group NH) and 13 hypertensive patients with cardiac hypertrophy (Group HH) were studied during multistage exercise using a supine bicycle ergometer. The shortening fraction (SF) and the peak negative dD/dt in Group HH, being within the normal range, tended to be smaller than those in Group N at the 75-watt load. The mean value of the peak positive dD/dt (+dD/dt) in Group HH was significantly smaller than that in Group N at rest and during the 75-watt load. The percent increase of plasma norepinephrine (NE) levels (% delta NE) at the 75-watt load was significantly greater in Group HH than in Group N. Plasma NE, in some patients with cardiac hypertrophy and compromised cardiac function, markedly increased (% delta NE greater than or equal to 186) during exercise. % delta NE was directly related to the left ventricular mass index among all of the groups, but it was inversely related to the SF, -dD/dt, and to +dD/dt at the 75-watt load. We conclude that the augmented sympathetic nerve activity may contribute to preserving left ventricular systolic function during exercise within the normal range in hypertensive patients with cardiac hypertrophy.

Adult↗
PubMed1988

Physiological significance of atrial natriuretic peptides in essential hypertension.

To investigate the significance of atrial natriuretic peptides (ANP) in essential hypertension, plasma ANP concentrations in 43 essential hypertensives, 16 borderline hypertensives and 17 normotensive controls were measured. Furthermore, effects of high-sodium and low-sodium intakes on plasma ANP concentration were examined in "salt-sensitive" [SS] and "nonsalt-sensitive" [NSS] patients with essential hypertension. Plasma ANP concentration was significantly higher in hypertensives than in borderline hypertensives and in normotensive controls. No significant difference in plasma ANP concentration was observed between borderline hypertensives and normotensive controls. Plasma ANP concentration increased with the high-sodium diet in both the SS and NSS patients, but the mean increment was significantly greater in the SS than the NSS patients. Urinary excretion of sodium was lower in the SS patients taking the high-sodium diet than the corresponding value in the NSS patients. These findings suggest that an increased level of circulating ANP in hypertensive patients represents a compensatory mechanism to offset further elevation of blood pressure and sodium retention.

Atrial Natriuretic Factor↗
PubMed1988

[Anti-inflammatory activity of the dry distillation tar of delipidated soybean (Glyteer) (2)].

The anti-inflammatory effects of Glyteer (GL) were investigated by its local administration using the CMC-pouch method in rats, and the effects were compared with those of betamethasone 17-valerate (BV, 1 mg), phenylbutazone (PB, 10 mg), flufenamic acid (FA, 10 mg), bufexamac (BM, 10 and 20 mg), bendazac (BZ, 10 and 20 mg), icthammol (IT, 10 mg) and pine tar (PT, 10 mg). At three hours after CMC-treatment, GL (10 mg) significantly inhibited not only the protein exudation, but also the leucocyte migration. The inhibitory activity of GL on the leucocyte migration had the same potency as that of FA, but was stronger than those of PB, BV, BM, BZ, IT and PT. Furthermore, in relation to the leucocyte migration, GL markedly inhibited not only the neutrophil, but also the macrophage migration. At three hours after CMC-treatment, the inhibitory activity of GL on the neutrophil migration had the same potency as those of PB and FA, but was stronger than those of BV, BM, BZ, IT and PT. On the other hand, GL, BM, BZ, FA, IT and PT had an inhibitory activity on the macrophage migration, and the activity was more potent in GL, FA and IT. From these results, it is suggested that the inhibition of GL on increased vascular permeability and leucocyte migration is one of the mechanisms of its anti-inflammatory action.

Administration, Topical↗
PubMed1988

Dissolution of antisecretory and cytoprotective action of PGE2 in rats.

Oral administration of 60% ethanol in 150 mM HCl (HCl.ethanol) to rats produced gastric mucosal lesions within 1 hr. PGE2 given s.c. at 0.1 to 3 mg/kg 0.5 hr before HCl.ethanol significantly prevented the lesion formation. The protection afforded with 3 mg/kg of PGE2 persisted for 6 or 12 hr after administration. PGE2 given s.c. at 3 mg/kg significantly inhibited gastric secretion in pylorus-ligated and intact rats, but the action disappeared 6 hr later.

Animals↗
PubMed1988

Effects of topical application of acidified omeprazole on acid secretion and transmucosal potential difference in anesthetized rat stomachs.

Effects of topical application of omeprazole on transmucosal potential difference (PD), luminal pH and histamine-stimulated acid secretion were examined in anesthetized rat stomachs, and they were compared with those of systemic administration. Omeprazole was suspended in 1% CMC with NaHCO3 (pH 9.0) or dissolved in 0.1 N HCl (pH 1.0). Both omeprazole (30 mg/kg, pH 9.0) and cimetidine (100 mg/kg), given i.d., increased the pH and inhibited acid secretion induced by histamine (8 mg/kg/hr, i.v.), while basal gastric PD was markedly elevated only by the former. Similar responses in PD, pH and acid output were obtained dose-dependently after brief exposure of the stomach (10 min) to omeprazole (0.3-30 mg/kg), even in acidic conditions, but the effects of acidified omeprazole disappeared depending upon the latency period in 0.1 N HCl; there was no effect when applied at more than 30 min after dissolution. Of interest, subsequent exposure of the stomach to a mercaptane compound (cysteine, 100 mg/kg) for 30 min significantly reversed the antisecretory effect of omeprazole (both i.d. and i.g.) but not of cimetidine. These results suggest that omeprazole has a local antisecretory action even in acidic stomachs, probably through an inhibition of the H+/K+ATPase activity, and the increase of PD caused by omeprazole may be a characteristic phenomenon seen after the blockade of H+/K+ ATPase, but is not associated with acid inhibition itself.

Administration, Cutaneous↗
PubMed1988

Cyclic GMP accumulation by atriopeptins in cultured rat renal and vascular smooth muscle cells.

To evaluate the role of cyclic guanosine monophosphate (cGMP) in the vascular and renal action of atrial natriuretic peptide (ANP), we compared the effects of atriopeptins (APs) on cGMP accumulation in cultured cells from rat mesenteric vascular smooth muscle (VSM), glomerular mesangium (GM) and renal papillary collecting tubule (RPCT), and also evaluated the relationship between renal sodium or water excretion and urinary cGMP in AP-infused rats. Both AP I and AP III increased intracellular cGMP levels dose-dependently in all types of cells, while they did not affect intracellular cAMP levels or prostaglandin synthesis. AP III was 100 times more potent than AP I. The magnitude change in cGMP levels was largest in GM cells. The sensitivity of VSM and GM cells to AP III were greater than that of RPCT cells. There were significant positive relationships between urinary excretion of sodium or water and that of cGMP levels in AP-infused rats. These results may suggest that GM and VSM cells are the principal targets for ANP to stimulate cGMP synthesis and, possibly, to exert the renal sodium and water excretion, and also support the hypothesis that cGMP mediates the cellular action of ANP.

Animals↗