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Biomedical subjects

T Furuta

Publications and source records attributed to T Furuta.

At least 343 records · Page 19Linked to original sources
PubMed1987

Distribution of cholinesterase in canine venous system.

Cholinesterase (ChE) activity was examined in 15 veins from dogs by pharmacological and histochemical procedures. Potentiation of acetylcholine (ACh)-induced contractile response by neostigmine was observed in helical and longitudinal strips of portal, mesenteric veins and middle segment of the inferior vena cava, but not in the other 12 veins. Histochemical studies with an electron-microscope (the method of Karnovsky-Roots) revealed that ChE activity was identified as high density granules around the smooth muscle cells only in the former three veins. The visible ChE activity was abolished by pretreatment with neostigmine.

Animals↗
PubMed1987

A regional difference in endothelium-dependent relaxation responses to acetylcholine in the canine venous system.

Endothelium-dependent relaxations of canine veins isolated from 15 different sites were examined. Acetylcholine (ACh, 10(-10)-10(-6) M) caused marked endothelium-dependent relaxations in the external jugular vein, superior vena cava, brachiocephalic vein, segment A (supradiaphragmatic portion) and D (infrarenal portion) of the inferior vena cava. However, only contractile responses were induced by ACh in the portal, mesenteric veins and the segment C of the inferior vena cava (between liver and renal veins) with or without endothelium. The other 7 veins showed only small endothelium-dependent relaxations (10-20%). These results indicated that the endothelium-dependent responses of canine veins to ACh are regionally different.

Acetylcholine↗
PubMed1987

Independent occurrence of hepatocellular and cholangiocellular cancer nodules in the liver.

We treated a patient in whom hepatocellular and cholangiocellular cancer nodules in the liver were of independent occurrence. A 57-year-old Japanese male was admitted with a diagnosis of liver tumour, detected by a scan on a follow-up study of chronic liver disease. Computed tomography and hepatic angiography demonstrated two nodules located on different sites of the right lobe of the liver and which were suggestive of primary liver cancers. He underwent hepatic resection and each tumour was histologically proved to arise independently from hepatocellular and bile duct origins. This may be the first report of patient surgically treated for two different types of carcinoma in the liver.

Adenoma, Bile Duct↗
PubMed1987

[Successful treatment of advanced gastric cancer by combined cisplatinum, mitomycin C and 5-FU administration. A case report].

A 55-year-old woman with gastric cancer underwent laparotomy and was found to have an unresectable tumor at the MC region, characterized by S3 (invasion into the pancreas), N3, P0, H0, Borrmann-II and moderately differentiated tubular adenocarcinoma. She was then treated by combined administration of cis-dichlorodiammine platinum (CDDP), mitomycin C and 5-fluorouracil (5-FU). A complete response was confirmed by upper gastrointestinal roentgenography and endoscopy. Upon reoperation 4 months after the initial laparotomy, a successful total radical gastrectomy with R2 (partially R3) lymph node dissection was performed. Histological examination of the specimens, including the stomach and lymph nodes, revealed no cancer cells in any region.

Adenocarcinoma↗
PubMed1987

[Experience with CDDP therapy in advanced and recurrent gastric cancer cases].

For 3 years beginning in 1984, 14 advanced and recurrent gastric cancer cases with measurable lesions (8 unresected cases, 3 cases of recurrence, 2 cases with non-curative resection, 1 case of no operation) were treated by CDDP therapy alone or in combination with other chemotherapies. CR was obtained in 2 of the 8 non-resected cases, radical gastrectomy being feasible in these 2 cases by second-look operation. Five of the 8 cases showed PD, and in 1 case the effect was rather obscure. One of the 2 non-curative resection cases achieved PR, and the other case was MR. One of the 3 recurrent cases was NC, the remaining cases being PD. The one case given no operation showed PD. Overall effectiveness of CDDP therapy for advanced and recurrent gastric cancer cases was seen in 3 (21.4%) of the 14 cases. All of these 3 cases showing effective CDDP therapy was elevated serum CEA values before the therapy, which was markedly reduced after starting the therapy, the reduction rate being very remarkable.

Adult↗
PubMed1987

Intra- and inter-species transmission and antigenic difference of Pneumocystis carinii derived from rat and mouse.

Pneumocystis carinii (Pc) derived from nude mice (MPc) and hypercorticonized rats (RPc) was subjected to transmission experiments via intranasal (i.n.) route into athymic nu/nu mice (BALB/c background) and run/rnu rats (Rowett hooded strain) and their euthymic heterozygotes rnu/+ rats. Although all these recipient animals received intensive cortisone treatment, MPc propagated only in nu/nu mice. In contrast, RPc strains from three different sources were transmitted successfully to both rats and mice irrespective of their athymicity. The MPc strain could not be transmitted to the other three rat strains used. When RPc organisms were successively propagated in nu/nu mice they lost their pathogenicity to rats after five passages. An antigenic difference between MPc and RPc was suggested by cross reaction of rabbit-raised antiMPc and antiRPc sera against MPc and RPc organisms. An absorption experiment of the sera with both MPc and RPc revealed cross reactivity as well as specific reactivity. The mouse passaged RPc seemed to change the antigenic characteristic to that of MPc.

Animals↗
PubMed1987

[Fundamental study of differential hypothermia treatment of brain tumor using an interstitial microwave antenna].

An interstitial microwave antenna system was devised for differential hypothermia treatment. It was evaluated for its ability to induce localized brain hyperthermia in hypothermic monkey. Ten brain hyperthermia trials have been performed in 6 monkeys. Under general anesthesia, the animals were put into ice water bath to keep the total body temperature at 30 degrees C. Following parieto-occipital craniectomy, a microwave antenna of 1.5 mm in diameter was inserted into the brain at depth of 2 cm, and the brain tissue was heated by 2450 MHz microwave irradiation. Thermal distribution was measured by thermistor probes and local cerebral blood flow (1-CBF) before and after heating was simultaneously measured by hydrogen clearance method. After the experiment, the animals were sacrificed and histopathological changes of the heated brain tissue were studied. Under total body hypothermia of 30 degrees C, the maximum cross-sectional diameter of the heated brain to 37 degrees C or above was about 4 cm. The temperature profile on the vertical plane presented a bell-shaped distribution. The 1-CBF of the heated brain increased with the elevation of the brain temperature and the blood flow at 37 degrees C is nearly twice as much as that of 30 degrees C. After one hour DH treatment, necrotic tissue was noted along the antenna axis where the temperature was maintained more than 50 degrees C, and this change was not recognized at a distance of 1 cm from the antenna where the temperature was maintained at 42 degrees C. This study indicates that interstitial microwave hyperthermia system can be used effectively to heat the localized brain tissue.

Animals↗
PubMed1987

Alagille's syndrome. A case with a hamartomatous nodule of the liver.

A male case of Alagille's syndrome associated with a hamartomatous nodule of the liver is described. The patient developed jaundice soon after birth, and was diagnosed as the syndrome with signs such as paucity of the intrahepatic bile ducts, pulmonary stenosis and embryotoxon in the cornea at 15 years of age. The liver was examined in recurrent biopsies and other tests. However, no evidence of liver cirrhosis was confirmed until his 15th year. The patient died of hepatic dysfunction when he was 17 years old. At autopsy, a large hamartomatous nodule was found in the liver showing biliary cirrhosis. Morphology of the nodule resembled that of focal nodular hyperplasia. Abnormalities of the large vessels were noted around the liver. Vascular abnormalities were also seen in the mass. The relation of these vascular abnormalities to etiological background of the syndrome and occurrence of the nodular lesion is discussed.

Adolescent↗
PubMed1987

Action of 7-ethylcamptothecin on tumor cells and its disposition in mice.

Some biological effects of camptothecin (CPT) and its new derivative 7-ethylcamptothecin (ECPT) were studied. The drugs were effective against murine leukemia; ECPT was more effective than CPT. Ip administration of ECPT or CPT gave maximum treated/control values of 325% and 232%, respectively. The drugs also inhibited the growth of KB cells in vitro, 50% effective doses of 3.5 ng/ml of ECPT and 8.6 ng/ml of CPT, indicating the stronger activity of ECPT. Pharmacokinetic studies of the drugs in mice showed that ECPT had a longer biological half-life in the terminal phase and a larger amount remained in the plasma compared with CPT. After iv administration of ECPT, the drug accumulated in the intestine, suggesting that the main route of excretion of the drug is through the biliary tract. The study on cell cycle progression by flow cytometry suggested that the main effect of both drugs on L1210 cells was the blocking of G2-M phase. These results suggest that the main reasons for the superior antitumor activity of ECPT compared with CPT are as follows: (a) ECPT had a stronger growth-inhibiting activity against tumor cells, and (b) ECPT remained in the intestinal tract for a longer time and in higher amounts when administered in vivo.

Animals↗
PubMed1986

The plasmin heavy chain-urokinase conjugate: a specific thrombolytic agent.

Low molecular weight urokinase (LMW-UK) was coupled to the heavy chain of plasmin to make it able to bind to fibrin. The purified conjugate (PHC-UK conjugate), which consisted of equimolar concentrations of each starting material had a molecular weight of 93,600, bound tightly to fibrin-monomer-Sepharose and was not washed off with 1 M NaCl, but was eluted specifically with epsilon-amino caproic acid. The conjugate showed higher fibrinolytic activity than HMW-UK. A control conjugate prepared by coupling human serum albumin to LMW-UK (HSA-UK conjugate) showed the same fibrinolytic activity as HMW-UK. The half-lives of these two conjugates in rabbits were about 3 times that of HMW-UK. In an experimental pulmonary embolism model in rabbits, the PHC-UK conjugate showed about 10 times higher thrombolytic activity than HMW-UK, while the HSA-UK conjugate showed similar thrombolytic activity as HMW-UK, and moreover caused severe systemic fibrinogen breakdown. Thus the significant increase in thrombolytic activity after injection of PHC-UK conjugate into rabbits may be due to its newly acquired fibrin binding activity, and not to increase in its half-life. It is concluded that the PHC-UK conjugate may be useful in treatment of thrombosis.

Animals↗
PubMed1986

Different types of relationship between beta-adrenergic relaxation and activation of cyclic AMP-dependent protein kinase in canine saphenous and portal veins.

We examined the relationships between the relaxation mediated by beta-adrenoceptor and either the associated cyclic AMP production or the activation of cyclic AMP-dependent protein kinase (A-PK) in canine saphenous and portal veins. In the saphenous vein constricted with methoxamine, isoproterenol caused concentration-dependent relaxation (maximum relaxation 92.7%), and concomitant increases in cyclic AMP and A-PK activity ratio (from 52.8 to 73.5%). The portal vein was only slightly relaxed by isoproterenol (14.7% in the longitudinal strips) after constriction with methoxamine, while cyclic AMP and A-PK activation increased significantly. Isoproterenol markedly activated A-PK of the portal vein after KCl constriction (from 52.6 to 74.6%) but the maximum relaxation was only slight (13.3%). The portal vein also showed a smaller relaxation response to either forskolin or dibutyryl cyclic AMP than the saphenous vein. These results indicated that the relationship between the relaxation response to isoproterenol and either cyclic AMP production or A-PK activation was different in the saphenous and portal veins.

Animals↗
PubMed1986

Quantitative estimation of quaternary ammonium neuromuscular blocking agents in serum by direct insertion probe chemical ionization mass spectrometry.

A new method based on selected ion monitoring chemical ionization mass spectrometry was developed to measure the quaternary ammonium neuromuscular blocking agents, pancuronium and vecuronium, in serum. An ion-pair extraction procedure is utilized to separate the compounds of interest from biological fluids. The intensities of the ion currents produced by the bisamines formed from the drugs and the corresponding deuterated internal standards through thermolytic dequaternization are monitored. The assay shows good linearity over the range of 1-500 ng/ml. This assay has been utilized in a variety of clinical pharmacokinetic studies involving surgical pediatric, geriatric and obstetric patients requiring anesthesia.

Chemical Phenomena↗
PubMed1986

Intracranial hypertension and cerebrospinal fluid production in dogs: effects of furosemide.

A method using chronically prepared, anesthetized dogs was devised for studying the effects of treatments of intracranial hypertension induced by applying a reversible extradural mass lesion while simultaneously measuring production of cerebrospinal fluid. This was measured with a ventricular-cisternal perfusion technique in which the rate of cisternal outflow could be controlled by a pump and matched to the inflow, allowing intracranial pressure to fluctuate despite simultaneous measurement of cerebrospinal fluid formation. Elevations of intracranial pressure to the range 20 to 35 Torr were induced and maintained during perfusion, but elevations above 35 Torr would not permit continued perfusion. At normal intracranial pressure, 10 Torr or less, rates of cerebrospinal fluid formation were the same whether the outflow controlling pump or free outflow was used. Formation of cerebrospinal fluid decreased progressively as intracranial pressure increased above 20 Torr. It also decreased with time after the start of perfusion during the course of 5 h, but returned to the initial range during the control phase of subsequent experiments in the same animal. Furosemide, 3 mg kg-1, i.v., had no significant effect on rate of formation but did induce a small decrease in ICP in time-controlled experiments in which i.v. fluid replacement limited net fluid losses to 20 ml kg-1 with no change in mean arterial or central venous pressures.

Animals↗
PubMed1986

Acute liver failure in rats inhibited by intrasplenic administration of OK-432.

Intrasplenic administration of OK-432, an immunostimulant derived from Streptococcus, prevented hepatic failure induced in rats by D-galactosamine. When OK-432 was given 1.0 K.E. (Group I) or 0.1 K.E. (Group II) into the subcutaneously transpositioned spleen three times prior to dosing with D-galactosamine, survival rates were 100 and 87%, respectively. On the contrary, with a splenic injection of saline (Group III), the survival rate was 47 and 32% in rats given OK-432 1.0 K.E. intraperitoneally (Group IV). The poisoned rats given no pretreatment (Group V) survived at a rate of 26%. These results show that intrasplenic administration of OK-432 leads to a significant enhancement of survival. Metabolic data and histological findings were compatible with survival rates, in each group. Activation of the reticuloendothelial function by the intrasplenic administration of this immunostimulant seems to have prevented acute liver failure.

Acute Disease↗
PubMed1986

Regional variation in beta-adrenoceptor-mediated relaxation of canine veins.

Three types of vasorelaxants were used to test the responses of canine veins isolated from 13 different sites: isoproterenol, papaverine and nitroglycerin. Strips were preconstricted with methoxamine (5 X 10(-6)-10(-5) M), KCl (50 mM) and PGF2 alpha (1 microgram/ml), and were relaxed by cumulative addition of relaxants. Isoproterenol caused more than 80% relaxation after preconstriction with methoxamine in cephalic, external jugular, azygos, renal, femoral, lateral saphenous veins and the supradiaphragmatic and infrarenal portions of the inferior vena cava, all of which are veins of the body wall. Pulmonary and splenic veins also showed marked relaxation with isoproterenol. However, maximal relaxation responses of portal, mesenteric veins and segment C of the inferior vena cava (a portion between liver and renal veins), which are embryologically related to the digestive tube, were less than 30%. Similar regional differences in the relaxation responses to isoproterenol were obtained after preconstriction with KCl or PGF2 alpha. Papaverine and nitroglycerin caused nearly uniform relaxation in all veins, although relaxations of segment C of the inferior vena cava were slightly less than those of other veins. These results indicated that there is a regional difference in the relaxation responses of the canine venous system to isoproterenol, and such a difference may be related to its embryogenesis.

Animals↗