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Biomedical subjects

H Yoshimura

Publications and source records attributed to H Yoshimura.

At least 379 records · Page 21Linked to original sources
PubMed1989

Mechanism of biological formation of cannabielsoin from cannabidiol in the guinea-pig, mouse, rat and rabbit.

Biological formation of cannabielsoin (CBE) from cannabidiol (CBD) was studied in the guinea pig, mouse, rat and rabbit in vitro. Emphasis was placed on the elucidation of this formation mechanism. The enzyme activity of CBE formation was localized in hepatic microsomes. The enzymatic reaction required nicotinamide adenine dinucleotide phosphate (NADPH) and molecular oxygen, and showed an optimal pH around 7.3. The microsomal CBE-forming activities decreased in the following order; guinea pig greater than mouse greater than or equal to rabbit greater than or equal to rat. The CBE formation in the guinea pig hepatic microsomes was suppressed with various inhibitors of cytochrome P-450 such as SKF 525-A, alpha-naphthoflavone and carbon monoxide, but not by disodium ethylenediamine tetraacetate. When incubated with the microsomes either in the presence or absence of NADPH, a synthetic epoxide of CBD, 1S, 2R-epoxy-CBD-2',6'-diacetate was easily and exclusively converted to CBE. On the other hand, 1R, 2S-epoxy-CBD was not changed to CBE at all, but to several oxidized metabolites. These results suggest that CBD is biotransformed to 1S,2R-epoxy-CBD with hepatic microsomal monooxygenase system including cytochrome P-450, and the epoxide is immediately converted to CBE.

Animals↗
PubMed1989

Characteristics of the gastrointestinal absorption of morphine in rats.

The absorption characteristics of morphine were investigated by using rat gastrointestine. Absorption and transport experiments were carried out by the in situ loop and the in vitro everted sac methods, respectively. Brush border membrane vesicles (BBMVs) were used for uptake experiments. Morphine and its metabolites, morphine-3-glucuronide (M-3-G), and morphine-6-glucuronide (M-6-G), in biological samples were simultaneously determined by high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection and electrochemical detection. In the in situ loop method, morphine was well absorbed in the order of jejunal site greater than duodenal site greater than ileal site greater than middle intestinal site greater than rectal site, but it was poorly absorbed from the stomach. In each of the everted duodenal and jejunal sacs, 2,4-dinitrophenol, a metabolic inhibitor, inhibited the transport of morphine from the mucosal side to the serosal side. Further, HgCl2 pretreatment reduced the absorption of morphine from the duodenal and the jejunal loops. The initial uptake of morphine by BBMVs was stimulated in the presence of an H+ gradient (inner pH 7.5 and outer pH 5.0) and an overshoot phenomenon was observed. The initial uptake showed concentration dependence, i.e., it was saturable. Results obtained in this study indicate that carrier-mediated transport stimulated by the H+ gradient is partly involved in the duodeno-jejunal absorption of morphine, although morphine is passively absorbed from other sites.

Animals↗
PubMed1989

Synthesis and analgesic effect of normorphine-3- and -6-glucuronides.

Normorphine-3- and -6-glucuronides were synthesized, and their analgesic effects were examined. Normorphine-3-glucuronide was obtained by condensation of normorphine with acetobromoglucuronate in the presence of sodium hydroxide in acetone. On the other hand, normorphine-6-glucuronide was synthesized by condensing N,O3-biscarbobenzoxynormorphine with acetobromoglucuronate in the presence of silver carbonate, and removing the protecting groups from the resultant reaction product by catalytic hydrogenation and solvolysis with sodium methoxide and barium hydroxide. The analgesic effect of normorphine-6-glucuronide (ED50 0.036 nmol/mice) was 125-fold more potent than that of normorphine in mice injected i.c.v. Normorphine-3-glucuronide was shown to be 37% effective at a dose of 2 nmol/mice, but induced convulsion at higher doses when given by i.c.v. injection.

Analgesics, Opioid↗
PubMed1989

Peroxidase activities in autonomously functioning nodules and adjacent non-tumorous portions of thyroids.

Peroxidase activities of autonomously functioning thyroid tumors (T) and surrounding non-tumorous tissue (N) in 5 patients were determined by employing guaiacol or iodide as the second substrates. The mean values for specific activities of T were 30 times (in iodide oxidation assay) or 4 times (in guaiacol oxidation assay) as high as those in N, being significantly higher than those of non-functioning tumors. The thyroglobulin-iodination activity of thyroid peroxidase in T was also found to correlate well to the iodide oxidation activity. These results suggest that the enhanced peroxidase activity in the nodules plays an essential role in the function of autonomously functioning thyroid nodules.

Adenoma↗
PubMed1989

Metabolic fate of strychnine in rats.

1. The urinary and faecal excretions of radioactivity, in rats dosed with 3H-strychnine at 0.5 mg/kg subcutaneously, were approx. 30% and 65% of the dose in 7 days, respectively. The radioactivity was mostly excreted within 24 h. 2. Approx. 6% and 3% dose was excreted into urine and faeces, respectively, as unchanged strychnine. 3. Urinary metabolites were extracted from rat urine and purified by silica gel column, t.l.c. and h.p.l.c. Six urinary metabolites, namely, strychnine N-oxide, 21 alpha,22 alpha-dihydroxy-22-hydrostrychnine, 21 alpha,22 beta-dihydroxy-22-hydrostrychnine, 2-hydroxy-strychnine, strychnine 21,22-epoxide and 16-hydroxystrychnine, were identified by comparison with authentic samples by g.l.c.-mass spectrometry. The major metabolites of strychnine in vivo was strychnine 21,22-epoxide.

Animals↗
PubMed1989

Further studies on metabolism in vivo of 3,4,3',4'-tetrachlorobiphenyl in rats: identification of minor metabolites in rat faeces.

1. Metabolism in vivo of 3,4,3',4'-tetrachlorobiphenyl (TCB) was investigated in male Wistar rats. 2. Five new minor metabolites in addition to two previously identified major metabolites (5-hydroxy-3,4,3',4'-TCB and 4-hydroxy-3,5,3',4'-TCB) were isolated as methylated derivatives from faeces of rats treated with 3,4,3',4'-TCB, by silica gel column chromatography and subsequent preparative t.l.c. 3. Among these methylated metabolites, three were identified as dimethoxy-TCB, and one as monomethoxy-trichlorobiphenyl (TriCB), by g.l.c.-mass spectrometry. By comparison with synthetic standards they were fully identified as 2,5-dimethoxy-3,4,3',4'-TCB, 4,4'-dimethoxy-3,5,3',5'-TCB, 5,6-dimethoxy-3,4,3',4'-TCB, and 4-methoxy-3,3',4'-TriCB, respectively. The structures of these metabolites in rat faeces should therefore be 2,5-dihydroxy-3,4,3',4'-TCB, 4,4'-dihydroxy-3,5,3',5'-TCB, 5,6-dihydroxy-3,4,3',4'-TCB, and 4-hydroxy-3,3',4'-TriCB. 4. One further metabolite was isolated, which was shown to be an oxepin, existing in a state of equilibration with the 4',5'-oxide of the major metabolite, 4-hydroxy-3,5,3',4'-TCB, by mass and 1H-n.m.r. spectra. On standing for several months, this metabolite isomerized to a new compound with a different g.l.c. retention time, which on methylation yielded a product identical with synthetic 4,4'-dimethoxy-3,5,3',5'-TCB by g.l.c.-mass spectrometry. From these results this metabolite was assumed to be an oxepin, equilibrated with 4-hydroxy-4',5'-epoxy-3,5,3',4'-TCB.

Animals↗
PubMed1989

[Cerebral blood flow imaging in patients with moyamoya disease].

The usefulness of IMP-SPECT and rCBF image by 133Xe inhalation method on rCBF in patients with moyamoya disease was studied. Six patients with moyamoya disease were diagnosed by cerebral angiogram, and STA-MCA anastomosis technique and EMS were done to reconstruct the rCBF. Low perfusion areas were detected around the cerebral infarction and hemorrhage and that of anterior and middle cerebral arteries by IMP-SPECT and 133Xe-rCBF image met by X-ray CT. After surgery, 4 out of 6 cases showed the improvement of rCBF by IMP-SPECT and 133Xe-rCBF image, as for clinical symptoms, there were reduction of TIA in 3 cases, and no rehemorrhage in 3 cases. In summary IMP-SPECT and 133Xe-rCBF image may be useful method to evaluate the rCBF in moyamoya disease and the change of rCBF post STA-MCA anastomosis technique and EMS.

Adult↗
PubMed1989

Zoonotic Onchocerca in a Japanese child.

A female Onchocerca was found in histopathological sections of a nodule removed from the foot of a 2-year-old girl in southern Japan. As in previously reported cases in Switzerland, Crimea, Canada, and the USA, evident morphological features of the worm resembled those of Onchocerca gutturosa and O. cervicalis, which are known to exist in cervical ligaments of cattle and horses, respectively, in Japan and elsewhere.

Animals↗
PubMed1989

[Distribution of pulsed intra arterial infusion chemotherapy in hepatic carcinomas].

Evaluation of "Gianturco-Wallace chemotherapy pulser," which was developed to produce a more homogeneous drug distribution of the tumors in intra-arterial infusion chemotherapy, was assessed by comparative study of pulsed and nonpulsed arterial radionuclide infusion using Tc-99m pertechnetate for 18 cases of hepatic carcinomas (11 cases of hepatocellular carcinomas and 7 cases of metastatic hepatic carcinomas). Tc-99m pertechnetate, 740 MBq (20 mCi) diluted with saline (30 mL) was infused with or without pulse through the catheter into the hepatic artery at a rate of 1mL per minute. The intrahepatic dynamic radionuclide distribution was analyzed by the time activity curves of ROIs in the tumor and nontumor areas. Pulsed infusion interrupted laminar flow and produced more homogeneous radionuclide distribution in the liver, and combination of pulsed and nonpulsed infusion also produced better radionuclide distribution in the areas of the tumors. This method using Tc-99m pertechnetate was very useful as a simulation to determine the dynamic drug distribution of the tumor and non-tumor region in intraarterial infusion methods.

Antineoplastic Agents↗
PubMed1989

[Ultrasonic detectability of multiple small hepatic nodules].

We analyzed the ultrasonic detectability of multiple daughter nodules accompanied by 18 hepatocellular carcinomas and multiple small nodules in 11 metastatic liver tumors identified by infusion hepatic angiography. In the cases of hepatocellular carcinoma, ultrasonic detectability of daughter nodules was remarkably limited. If any daughter nodules are detected by US, there is the great possibility that many other daughter nodules are undetected. However, US is effective in detecting small nodules in the metastatic liver tumor.

Carcinoma, Hepatocellular↗
PubMed1989

[The evaluation of the bone marrow accumulation of Ga-67 citrate].

The bone marrow distribution of Ga-67 citrate may be influenced by various elements in serum. In order to make these points clear, 1,955 whole body images were reviewed on the relationship between the accumulation of bone marrow and laboratory examination data of each patients. Increasing accumulation in the bone marrow was determined as positive when the bones of lower extremities were deposited on the images, because these bones was not visualized in normal gallium image. Laboratory data of 20 patients without having bone marrow accumulation was used as control. The positive findings of bone marrow accumulation was observed in 38 patients (2%) including 23 malignancies and 15 benign disease. The malignant tumor infiltration to the bone marrow was demonstrated by bone marrow aspiration biopsy in 2 out of 7 patients with bone marrow accumulation of Ga-67. Seven out of 15 patients with benign disease were collagen disease such as aortitis syndrome or SLE. The values of hemoglobin, hematocrit, serum iron and creatinine clearance were significantly lower in the patients with positive findings in comparison with control. These results suggest that the lower level of serum iron and anemia may cause increasing bone marrow accumulation of Ga-67 citrate.

Bone Marrow↗
PubMed1989

[Clinical cerebral perfusion scintigraphy with 123I-IMP].

At the first place, some experimental knowledges on the biodistribution of IMP were described for the understand of this agent. And on the basis of our clinical experience, the usefulness of cerebral perfusion imaging using SPECT and IMP was reviewed. The patients with possible ischemic cerebral diseases such as infarction, TIA and RIND are main candidates for this examination. Clinical significance of the so-called "redistribution" of IMP was discussed in detail. Dementia and epilepsy are considered to be the other indication. With improvement of the method, cerebral perfusion imaging may be accepted as essential test in the hospital dealing with the patient with neuropsychiatric deficits.

Amphetamines↗
PubMed1989

[A case of pulmonary mucormycosis accompanied by lymphocytic leukemia successfully treated by pulmonary lobectomy].

A 51 years old man with acute lymphocytic leukemia who was treated with antileukemic chemotherapy, developed sepsis and pneumonia. Secondary infection with Mucor intervened with abscess formation cured by lobectomy. The patient is doing well without evidence of recurrence, and treated successfully with anti-leukemic chemotherapy. Surgical treatment offers the last chance of survival in similar cases.

Humans↗
PubMed1989

[Tissue distribution, inductive effect on liver enzymes and acute toxicity of 2,3,4,7,8-pentachlorodibenzofuran in Golden Syrian hamsters].

The hamsters have been known to be the least sensitive mammalian species to the acute toxicity of highly toxic polyhalogenated hydrocarbons such as 2,3,7,8-tetrachlorodibenzo-p-dioxin. In the present study, the tissue distribution, inductive effect of liver enzymes and acute toxicity of 2,3,4,7,8-pentachlorodibenzofuran (PenCDF) in male Golden Syrian hamsters were examined. The highest content (about 48% of dose) of PenCDF was found in the liver 5 days after a single i.p. dose of 1.0 mg/kg. The amount ranging about 5 to 10% of dose was also distributed to mesentery, skin and muscle. In liver, the distribution of PenCDF was just parallel to that of cytochrome P-450 (P-450), marker enzymes of liver endoplasmic reticulum, suggesting that PenCDF binds to P-450. The mode of inductive effects of PenCDF in hamsters was 3-methylcholanthrene-type as reported previously in rats. However, the typical enzymes such as benzo(a)pyrene 3-hydroxylase and DT-diaphorase were induced to a relatively less extent than did in rats. In hamsters pretreated with PenCDF at a dose of 0.5 mg/kg, the potent atrophy of thymus and the 3-fold increase of liver lipid peroxide were observed, whereas the body weight gain was not suppressed at all. These results suggest that the induction of liver enzymes and the atrophy of thymus might not be the direct cause of PenCDF-induced lethality in hamsters.

Animals↗
PubMed1989

[Studies on distribution, excretion and subacute toxicity of squalane in dogs].

In the previous papers, we demonstrated, by using rats, that squalane (2,6,10,15,19,23-hexamethyltetracosane) could stimulate the fecal excretion of 2,3,4,7,8-pentachlorodibenzofuran, which was regarded as the most important etiologic agent of yusho among PCB and PCDF congeners found in the causal rice oil. We also reported that, in rats, squalane was not essentially absorbed from the gastrointestinal tract, and did not show any appreciable side effects during the 3-month treatment. In the present paper, we have investigated the distribution, excretion and subacute toxicity of squalane in beagle dogs. The fecal excretion of squalane accounted for about 83% of dose during the initial 2 days after administration at a single oral dose of 1,200 mg/kg to male dogs. On day 3, absorbed squalane was mostly distributed to the hair and the skin, and the concentrations in these tissues were decreased on day 6. These results suggested that most of squalane administered orally was not absorbed from the gastrointestinal tract, but a part was absorbed and excreted through the hair. In addition, squalane distributed into the liver was found to be eliminated rather slowly. A long-term (13-week) treatments with squalane orally at doses of 400 mg/kg/day or 1,200 mg/kg/day in male and female dogs, resulted also in accumulation of squalane in the liver at a level of about 3% (400 mg/kg) or about 6% (1,200 mg/kg) of the daily dose. This accumulation of squalane in the liver was highest among all the tissues. Nevertheless, no appreciable toxic signs were observed in the serum biochemical tests and the hepatic functional test for squalane groups. Therefore, squalane accumulating in the liver, did not seem to disturb the hepatic physiological functions. It was suggested also in a long-term treatment that the skin and the hair played the most important role in the elimination of squalane. In conclusion, the present studies on subacute toxicity tests suggested that squalane did not give any significant toxic effects on dogs as well as rats.

Animals↗
PubMed1989

[Non-vascular interventional radiology expandable metallic biliary endoprosthesis and afterloading intracavitary irradiation for malignant biliary obstruction].

Biliary endoprostheses (EMBE) using expandable metallic stents or intracavitary irradiation with remote afterloading (RALS) were carried out in eighteen patients with malignant biliary obstruction. There were 11 patients with bile duct cancer, 3 patients with gallbladder cancer, 2 patients with pancreas cancer and 2 patients with metastatic gastric cancer. The favourable results were obtained. Placement of stents was successful in all 17 cases in which the EMBE was conducted, and in all cases but one, the duct was cleared. At the follow-up of 2 to 59 weeks, all stents maintained patency and there were no severe complications, although only one patient had jaundice due to obstruction at the stented duct 4 months after EMBE. In nine cases, intracavitary irradiation with RALS was performed using a newly developed 14 Fr applicator. The bile duct walls at the irradiation site were smooth and expansion of the constricted area was seen. These results indicate that the combined use of EMBE and intracavitary irradiation with RALS could form a new part of treatment of malignant tumors of the bile duct in which radical surgery is not possible.

Bile Duct Neoplasms↗