Biomedical subjects

K Fujimoto

Publications and source records attributed to K Fujimoto.

At least 649 records · Page 36Linked to original sources

PubMed1990

A novel cardio-excitatory peptide isolated from the atria of the African giant snail, Achatina fulica.

An undecapeptide which potentiates the beat of the ventricle in the African giant snail, Achatina fulica Ferussac, was purified from the atria of the snail. Its primary structure was determined to be H-Ser-Gly-Gln-Ser-Trp-Arg-Pro-Gln-Gly-Arg-Phe-NH2. This peptide was found to have excitatory actions not only on the ventricle but also on the penis retractor muscle, the buccal muscle and the identified neurons controlling the buccal muscle movement of Achatina.

Amino Acid Sequence↗

PubMed1990

Hypothalamic histamine modulates adaptive behavior of rats at high environmental temperature.

Histamine content in the rat hypothalamus was lower at 4 degrees C and higher at 31 degrees C compared to that at 21 degrees C. Pretreatment with alpha-fluoromethylhistidine, a 'suicide' inhibitor of histamine decarboxylase, attenuated both the increased level of hypothalamic histamine and rat adaptive behavior at 31 degrees C. Increase of histamine content in the hypothalamus appears to be an important factor contributing to rat adaptive behavior to high environmental temperature.

Adaptation, Physiological↗

PubMed1990

[Selective segmental sclerotherapy of the liver by transportal ethanol injection--a complete remission case of hepatocellular carcinoma].

Selective segmental sclerotherapy of the liver by transportal ethanol injection (SSS) was devised and evaluated in a case of hepatocellular carcinoma. The patient was a 72-year-old man suffering from unresectable hepatoma. Injected ethanol with an amount of 20 ml into the portal branch under occluding the portal flow by balloon catheter produced complete necrosis of the liver proportional to the injected liver segment including the tumor on CT. Because of ethanol perfusion into sinusoid level by wedge injection, its cytotoxicity maybe affected liver cells directly. In this case, there has been no evidence of inadvertent liver damage and a significant rise in the blood ethanol level. The present technique of SSS in this clinical case and our past animal experience seemed to yield the same condition as resection without surgical disadvantages and be apparently a safe method, which is suggested for clinical use for several hepatic tumors.

Aged↗

PubMed1990

Hepatic subsegmentectomy with segmental hepatic vein sacrifice.

There is no clinical disorder in partial Budd-Chiari syndrome or in a major hepatic vein ligation in hepatic trauma. When considering these findings, it is significant to investigate hepatic subsegmentectomies in which a major hepatic vein is sacrificed. We performed such hepatic subsegmentectomies in nine cases of hepatocellular carcinoma. With the sacrifice of the right hepatic vein, S7, S8 resection was done in three patients, S7 resection in two patients, S8 resection in one patient, and S5 resection in one patient. With the sacrifice of the middle hepatic vein, S8 resection was done in two patients. These resections were successfully performed with no postoperative problem. Further, there were no significant differences in postoperative liver function tests of the patients from those of a control group of the commonly performed systematic segmentectomy and subsegmentectomy. By performing such resections, resection was made possible in three cases and curative resection was made feasible in six cases.

Aged↗

PubMed1990

Determination of lipid hydroperoxides in low density lipoprotein from human plasma using high performance liquid chromatography with chemiluminescence detection.

A high performance liquid chromatographic system with chemiluminescence detection (HPLC-CL) was used for determining phospholipid hydroperoxides in human plasma low density lipoprotein (LDL). This system involved separation of phospholipids from LDL-total lipids with normal phase silica gel HPLC and post-column detection of hydroperoxide-dependent chemiluminescence produced by luminol oxidation during the reaction of hydroperoxide with cytochrome c-haeme. By using HPLC-CL, we could detect phosphatidylcholine hydroperoxide (PCOOH) in human plasma LDL, and the LDL-PCOOH concentration was significantly higher in patients with atherosclerosis and hyperlipidemia than that of healthy volunteers. The LDL-PCOOH level was proportional to the plasma total cholesterol concentration.

Adolescent↗

PubMed1990

Rat urinary bladder carcinomas induced by N-butyl-N-(4-hydroxybutyl)-nitrosamine and N-methyl-N-nitrosourea.

The present investigation was conducted to examine the combination effect of N-butyl-N-(4-hydroxy-butyl)nitrosamine(BBN) and N-methyl-N-nitrosourea(MNU) in rat urinary bladder carcinogenesis. Experiment 1 was performed in the groups treated by oral BBN administration in combination with MNU intravesical instillation and their control groups. In the groups given both BBN and MNU, the ratio of rats with the nonpapillary type to carcinoma-bearing rats was significantly higher than in the controls. Since most of the carcinomas were non-invasive, the observation period was prolonged in the groups given both BBN and MNU in experiment 2. However, even after a longer observation period, no invasive carcinoma was observed. These results suggest that high-grade and invasive carcinomas similar to those induced by BBN and MNU in the heterotopically transplanted rat bladder cannot be induced in the natural bladder of the rat.

Animals↗

PubMed1990

Ca2(+)-ATPase cytochemistry in the spinal cord microvasculature of prenatal rats.

Membrane-bound Ca2(+)-ATPase activity was localized cytochemically in the blood vessels of the spinal cord of rat embryos to obtain a better understanding of the membrane activities of vascular cells. The cytochemical method revealed a growth of the parenchymal vasculature. In the parenchyma, reaction product was dense over the entire plasma membrane of voluminous endothelial cells provided with large nuclei and enriched cytoplasmic organelles, suggesting that the endothelial cells may be of a vascular sprout. The parenchymal vessels with a wide lumen were frequently associated with pericytes, and the Ca2(+)-ATPase activity was diminished in intensity on the luminal surface of the flattened endothelial cells. On the other hand, the endothelium of extraparenchymal capillaries exhibited Ca2(+)-ATPase activity primarily on the luminal surface of the plasma membrane. Quercetin, a Ca2(+)-transporting ATPase inhibitor, considerably decreased the abluminal activity in the voluminous endothelial cells with slit-like vascular lumen and the luminal activity of functioning capillary endothelium as well. Thus, a dual activity of Ca2(+)-ATPase, postulating for the activities of Ca2(+)-transporting ATPase and ecto-ATPase, was closely correlated with the maturation processes of the capillary endothelium.

Animals↗

PubMed1990

High reproducibility of regional abnormalities on interictal 123I-IMP SPECT brain scans in adults with partial epilepsy.

The reproducibility of two N-isopropyl-(iodine 123) p-iodoamphetamine (123I-IMP single photon emission computed tomography (SPECT) scans both taken during interictal periods was studied in 13 adult patients with partial epilepsy who had normal CT scans. The frequency of the seizures and the nature of the ictal symptoms were virtually unchanged during the interval between the two SPECT scans performed in each case. In 8 (72.7%) of 11 patients who had abnormal images consisting of focal hypofixation images of 123I-IMP, i.e. zones of decreased regional cerebral blood flow on the first scans, complete or partial regional reproduction of the SPECT abnormalities was observed. This high reproducibility supports the usefulness of SPECT scans in the regional diagnosis of epileptic foci.

Amphetamines↗

PubMed1990

Evidence for feeding elicited through antihistaminergic effects of tricyclic antidepressants in the rat hypothalamus.

We studied central mechanisms of antidepressants that affect feeding behavior in rats. The tricyclic compounds amitriptyline, doxepin and imipramine significantly induced feeding after their infusion into the third cerebral ventricle in the light phase, but the tricyclic, desipramine, and the dicyclic zimelidine, did not. Drinking was not affected by any compound tested. The relative order of potency in eliciting feeding was: amitriptyline and doxepin greater than imipramine greater than desipramine and zimelidine. To clarify the involvement of neuronal histamine in antidepressant-induced feeding, alpha-fluoromethylhistidine (FMH), a "suicide" inhibitor of histidine decarboxylase, was intraperitoneally administered before infusion of amitriptyline. FMH attenuated the amitriptyline's effect. Bilateral microinfusion of amitriptyline into the ventromedial hypothalamus or the paraventricular nucleus verfied that these are loci for the modulation of feeding by amitriptyline. In the lateral hypothalamus, amitriptyline was less effective. These findings indicate that tricyclic antidepressants directly facilitate feeding, which is, at least in part, mediated by histamine in the hypothalamus.

Amitriptyline↗

PubMed1990

Liver phosphatidylcholine hydroperoxidation provoked by ethionine-containing choline-deficient diet in mice.

It is shown that peroxidation of phosphatidylcholine (PC) is enhanced in liver of mice fed a hepatocarcinogenic choline-deficient diet containing 0.1% w/w ethionine. Mice were divided into 4 groups and fed for 4 weeks one of the following diets: choline-supplemented; choline-supplemented containing ethionine; choline-deficient; and choline-deficient containing ethionine. Phosphatidylcholine hydroperoxide (PCOOH) of liver lipids was measured by high performance liquid chromatography using a chemiluminescence detector. Mice fed a choline-deficient diet containing ethionine showed 6-fold higher PCOOH levels than the choline-supplemented control mice: the PCOOH/PC molar ratios of liver lipids were 32.3 X 10(-5) and 5.6 X 10(-5), respectively. In addition to this remarkable degree of lipid peroxidation in liver of mice fed the choline-deficient diet containing ethionine, we also observed a significant liver fatty infiltration, a decrease in plasma and liver alpha-tocopherol, and an increase in liver injury-indicative enzyme activities. Also, marker enzymes for hepatocarcinogenesis, glucose-6-phosphatase and gamma-glutamyl transpeptidase were affected. These data suggest that enhanced hydroperoxidation of phosphatidylcholine may participate in hepatocarcinogenesis provoked by choline deficiency in the presence of ethionine.

Animals↗

PubMed1990

Effect of cyclic guanosine monophosphate on hypoxic and angiotensin-II-induced pulmonary vasoconstriction.

We examined, in isolated blood perfused rat lungs, the effect of the cell permeable 8-bromo derivative of cGMP on pulmonary vasoconstriction induced by either alveolar hypoxia or angiotensin II. 8-Bromo cGMP dose-dependently reduced both hypoxia-(IC50 = 2.2 X 10(-5) M) and angiotensin-II-induced pulmonary vasoconstriction (IC50 = 5.0 X 10(-5) M). This effect of 8-bromo cGMP on pulmonary vasoconstriction was not affected by cyclooxygenase blockade. M & B 22948 (0.1 mM), an inhibitor of cGMP-phosphodiesterase, reduced synergistically with 8-bromo cGMP the hypoxia or angiotensin-II-induced vasoconstriction. The cGMP-phosphodiesterase inhibitor M & B 22948, by itself, selectively reduced hypoxia-induced vasoconstriction, suggesting a modulating effect of endogenous cGMP during hypoxic vasoconstriction.

3',5'-Cyclic-GMP Phosphodiesterases↗

PubMed1990

Lymphoepithelial cyst in the pancreas: a case report.

A case of lymphoepithelial cyst in the pancreas was reported. A 64-year-old man without any specific complaints was found to have a cystic lesion in the anterior portion of the pancreas, as revealed by ultrasonography of the abdomen at an annual medical examination in 1988. This was dissected easily from the pancreas. Histologically, it was diagnosed to be a benign lymphoepithelial cyst in the pancreas. Cysts of this type are rare, and their histogenesis is also not well understood.

Branchioma↗

PubMed1990

Decrease and recovery of choline acetyltransferase activity in medial thalamus and ventral tegmental area after destruction of pedunculopontine nucleus areas in the rat.

Choline acetyltransferase activities were measured in various forebrain regions 3, 7, 14, 21 and 28 days after bilateral lesions of the pedunculopontine nucleus area with ibotenic acid. The decrease was predominant in the ventral tegmental area and medial thalamus (especially at the caudal level). The decrease recovered as rapidly as 21 days after the lesions. It is concluded that the ascending cholinergic pedunculopontine projection is topographically organized within the thalamus and it appears that the effect of the experimental destruction of the projection recovered within a month.

Animals↗

PubMed1990

Pharmacological differentiation of presynaptic M1 muscarinic receptors modulating acetylcholine release from postsynaptic muscarinic receptors in guinea-pig ileum.

1. Effects of three muscarinic antagonists on electrically evoked ACh release and contractile response were investigated in longitudinal muscle strips of guinea-pig ileum suspended in an organ-bath and superfused with Krebs solution. ACh release was determined by a specific radioimmunoassay. 2. Telenzepine, a selective M1 muscarinic antagonist, increased the ACh release at a concentration of 100-fold less than that inhibiting the contractile response (10 vs 1000 nM). 3. AF-DX 116, a cardioselective M2 muscarinic antagonist, inhibited the contractile response at 10 microM, but did not affect the ACh release at this concentration. 4. (-)N-Methylscopolamine (NMS) did not affect the ACh release, but inhibited the contractile response at all concentrations tested (1-1000 nM), indicating (-)NMS can be used as an ileal specific postsynaptic muscarinic antagonist. 5. These data demonstrate that presynaptic muscarinic receptors modulating ACh release are distinct from postsynaptic ones involved in the contractile response and can be classified as M1 subtype.

Acetylcholine↗

PubMed1990

Structure and hypotensive activity relationships of tetrandrine derivatives in stroke-prone spontaneously hypertensive rats.

1. Structure and hypotensive activity relationships of tetrandrine (TD), an alkaloid isolated from the Chinese herb Radix stephaniae tetrandrae and its derivatives were investigated in conscious stroke-prone spontaneously hypertensive rats (SHRSP). 2. Derivatives substituted at the 7-O position with various types of alkyl group produced varying degrees of hypotensive effect. 3. While the demethylated derivative, fangchinoline (FC), and its acetylated compound had no effect on blood pressure, 7-O-methyl FC (TD), and 7-O-ethyl and 7-O-isopropyl FC at oral doses of 25 and 50 mg/kg produced a gradual and sustained hypotensive effect without any significant effects on heart rate and plasma renin concentration. 4. Substitution at the 7-O position with longer side chains such as n-propyl, n-butyl and n-pentyl groups reduced both the degree and duration of hypotensive activity. 5. Substitution of N-methyl groups at the 2 and 2' positions with quaternary ammonium or N-oxide attenuated the hypotensive activity. 6. The results of this study suggest a possibility that 7-O-ethyl and 7-O-isopropyl derivatives as well as TD can be considered as potential antihypertensive drugs because of the gradual onset and long duration of their hypotensive action in SHRSP.

Alkaloids↗

PubMed1990

Phospholipid hydroperoxide accumulation in liver of rats intoxicated with carbon tetrachloride and its inhibition by dietary alpha-tocopherol.

The formation and accumulation of phospholipid hydroperoxides, especially of phosphatidylcholine hydroperoxide (PCOOH), a primary peroxidation product of phosphatidylcholine (PC), in livers of carbon tetrachloride-intoxicated rats was investigated. PCOOH in liver and blood plasma was measured by a chemiluminescence-high-performance liquid chromatography procedure originally developed by Miyazawa et al. (Anal. Lett. 20, 915, 1987; Free Radical Biol. Med. 7, 209, 1989). Male Sprague-Dawley rats (120 g body wt., 5 weeks of age) were used in the experiments. The amount of PCOOH in the liver of control rats (CCl4-untreated) was 160 +/- 20 pmol/100 mg protein (mean +/- SD) and the PCOOH/PC molar ratio was 1.1 +/- 0.1 X 10(-5). In CCl4 (0.1 ml/100 g body wt.)-dosed rats, the liver PCOOH was 289 +/- 65 pmol/100 mg protein (PCOOH/PC = 2.4 +/- 0.4 X 10(-5], 764 +/- 271 pmol/100 mg protein (PCOOH/PC = 5.2 +/- 1.7 X 10(-5], and 856 +/- 165 pmol/100 mg protien (PCOOH/PC = 6.0 +/- 0.8 X 10(-5] at 6 h, 24 h, and 1 week after the dose, respectively. Under such conditions, the liver phosphatidylethanolamine hydroperoxide (PEOOH) level was not altered and the concentration was less than 100 pmol/100 mg protein even after the dose. The increments of liver PCOOH were suppressed 56% by the oral supplementation of DL-alpha-tocopherol (5 mg/100 g body wt./day) for a week before CCl4 administration. A relatively larger amount of PEOOH was found after stimulation of PC hydroperoxidation in the liver of rats with a large amount of CCl4 (0.25 ml/100 g body wt.) rather than with the small amount of CCl4 (0.1 ml/100 g body wt.).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

Comparative antitumor activity and intestinal toxicity of 5'-deoxy-5-fluorouridine and its prodrug trimethoxybenzoyl-5'-deoxy-5-fluorocytidine.

N4-Trimethoxybenzoyl-5'-deoxy-5-fluorocytidine (Ro 09-1390), a prodrug of the cytostatic 5'-deoxy-5-fluorouridine (5'-DFUR), was synthesized with the aim of reducing of the dose-limiting toxicity of 5'-DFUR, which is diarrhea. In mice bearing Lewis lung carcinoma, 5'-DFUR given po produced a substantial amount of 5-fluorouracil (5-FU) in the intestinal tract as well as tumors, where the enzyme pyrimidine nucleoside phosphorylase, essential for conversion of 5'-DFUR to 5-FU, is predominantly located. With the oral administration of Ro 09-1390 only a small amount of 5-FU was formed in the intestine; however, the administration of Ro 09-1390 and 5'-DFUR at the same dose produced similar amounts of 5-FU in tumor tissues. These differences in metabolism were reflected in their toxicity and antitumor efficacy. The administration of 5'-DFUR resulted in damage to the intestinal mucosal membrane and diarrhea in normal mice, whereas Ro 09-1390 was much less toxic to the intestinal tract. As regards antitumor activity, Ro 09-1390 and 5'-DFUR at equivalent doses inhibited the growth of Lewis lung carcinoma to similar extents. Since Ro 09-1390 was much less toxic to the intestinal tract than 5'-DFUR, mice bearing Lewis lung carcinoma could be given Ro 09-1390 daily over a longer period and at a higher dose, resulting in a longer survival time.

Animals↗

PubMed1990

Fat feeding increases size, but not number, of chylomicrons produced by small intestine.

To test the regulatory effect of dietary triglyceride (TG) on rat lymphatic apolipoprotein B (apo B) transport, lymph-fistula rats were infused intraduodenally for 8 h at 3 ml/h with a lipid emulsion containing 40 mumol TG labeled with glycerol [9,10-3H(N)]triolein, 7.8 mumol egg phosphatidylcholine, and 57 mumol sodium taurocholate in phosphate-buffered saline with or without 1 mg/h Pluronic L81 (L81). L81 is known to prevent lipid transport in the intestine by inhibiting the formation of chylomicrons (CM). This action of L81 is quickly reversible by merely replacing L81 infusion by saline infusion. In the control rats (without L81 added to the infusate), the amount of apo B secreted in either whole lymph, CM, or the very-low-density lipoprotein (VLDL) fractions did not change significantly during lipid infusion compared with fasting. Compared with the fasting, the apo B output in lymph during L81 plus lipid or saline infusion in the experimental rats did not change significantly. The lymphatic apo B output data were also supported by the incorporation studies using [3H]leucine. In summary, these data demonstrate that the absorption of a physiological load of lipid into lymph does not affect the apo B synthesis in the mucosa or the secretion of apo B in lymph. Furthermore, the action of L81 is probably not by inhibiting intestinal apo B production because apo B secretion was not affected by the presence of L81. This study also demonstrates that the number of CM particles made by the small intestine remains relatively constant during fasting or active lipid uptake and transport. During active lipid absorption, instead of increasing the number of CM, the enterocytes expand the size of the CM particles. Lastly, the number and TG content of VLDL particles synthesized and secreted by the small intestine also seems to remain relatively constant during fasting and active lipid absorption.

Animals↗