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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 253 records · Page 14Linked to original sources
PubMed1990

Anticonvulsant effects of zonisamide and phenytoin on seizure activity of the feline visual cortex.

The acute anticonvulsant effects of zonisamide (ZNS) and phenytoin (PHT) on seizure activity produced by electrical stimulation of the feline visual cortex were studied. The intravenous administration of ZNS 60 mg/kg reduced kindled generalized seizures into partial seizures, with marked reduction in the afterdischarge duration. ZNS also suppressed focal seizure activity of the visual cortex and produced a dose-related increase in the afterdischarge threshold. The anticonvulsant effect of ZNS (60 mg/kg) was comparable to that of PHT (15 mg/kg) and was observed in the absence of neurological toxicity and background EEG changes. The present findings demonstrated that ZNS possesses potent anticonvulsant action against focal seizure and its secondary generalization from the visual cortex.

Animals↗
PubMed1990

Studies on insulin-like substances in Korean red ginseng.

Korean red ginseng powder was found to contain adenosine and an acidic substance which inhibited epinephrine-induced lipolysis and stimulated insulin-mediated lipogenesis from glucose (3, 4). In the present experiment, the chemical structure of this acidic substance is determined to be pyro-glutamic acid. Pyroglutamic acid exhibits selective modulations toward the opposite metabolic pathways in rat adipocytes; it inhibits the lipolysis but rather stimulates the lipogenesis. Based on these results, we suggest to call these substances (adenosine and pyro-glutamic acid) "selective modulators".

Adenosine↗
PubMed1990

Inhibitory effect of tumor necrosis factor on gene expression of hormone sensitive lipase in 3T3-L1 adipocytes.

Recombinant human tumor necrosis factor (TNF) depressed the activities of both lipoprotein lipase (LPL) and hormone sensitive lipase (HSL) in 3T3-L1 adipocytes, 3 to 24 h after its introduction to the cells. HSL gene expression, as measured by Northern blotting analysis with 32P-labeled cloned HSL-cDNA, was also suppressed. These results suggested that the reduction in HSL activity caused by TNF resulted from inhibited gene expression of the enzyme.

Adipose Tissue↗
PubMed1990

Plastic injection method for preparing microvascular corrosion casts for SEM and its practical application.

This paper examines the application of the acryl plastic injection to the preparation of vascular corrosion microcasts for scanning electron microscopy (SEM). The original injection method using acryl plastic was described by Taniguchi, Ohta et al. in 1952 and 1955, under the title of "New improved method for injection of acrylic resin". Three dimensional observations were undertaken in our laboratory on the angiology at the macro- and microscopic levels of various organs from various mammals employing the original method. Based on this extensive experience, an injection method for preparing corrosion microcasts for use in SEM was devised in our laboratory. Microcasts prepared by the present method were able to demonstrate the fine vascular architecture of each organ. In general, although applications for preparing vascular microcasts of isolated and parenchymal organs are not so difficult, the method can be used to be applicable for demonstrating the fine vascular architecture related to or within hard tissues, as well as for investigating the morphological relations between changes of vascular patterns and restorative changes in the surrounding tissues affected by experimental operations. SEM microphotographs are also presented to illustrate actual practical applications.

Animals↗
PubMed1990

The facial artery of the common marmoset (Callithrix jacchus).

The facial artery and its ramifications in 7 adult common marmosets (Callithrix jacchus) were studied by the plastic injection method. The findings obtained are discussed in comparison with those for other primates. In the submandibular region, the facial artery arose from the external carotid artery at the height of the atlas via the linguofacial trunk on 10 of the total of 14 sides examined and independently on the other 4 sides. This common trunk always gave rise to the superior thyroid artery. The facial artery passed anterolaterally between the styloglossus muscle and the intermediate tendon of the digastricus muscle, giving off the styloglossal and the submandibular glandular branches, and anteroinferiorly medial to the pterygoideus medialis muscle. In a position anterior to this muscle, the submental artery and masseteric branch were derived. The submental artery gave off the medial pterygoid, the digastric, the cutaneous, the sublingual glandular and the mylohyoid branches, and then continued up to the median line, where it terminated to supply the genioglossus muscle. In the facial region, the facial artery passed anterosuperiorly along the anterior margin of the masseter muscle on 12 sides and away from it forwards on 2 sides, giving off the premasseteric branch in one of these 2 sides. It gave rise to the cutaneous, the buccal and the buccinator branches, the inferior labial artery and the communicating branch with the zygomatic artery. It terminated to divide into the superior labial and the naris lateral arteries, although the latter was lacking on 4 sides. The inferior labial artery gave off the mandibular marginal, the inferior labial marginal and the inferior labial glandular branches and terminated to anastomose with the mental artery. The superior labial artery divided into the superficial and deep branches, each of which continued as a nasal septal branch. The facial artery of the common marmoset usually ascended along the anterior margin of the masseter muscle and did not reach the medial angle of the eye.

Animals↗
PubMed1990

[Clinical characteristics of bronchial asthma in the elderly in relation to cell component in the airways].

Cellular responses in the airways of bronchial asthma, which might be affected with aging, were compared between 28 elderly (60 years old or more) and 28 younger (40 years old or less) patients with bronchial asthma. The cellular responses were observed to differentiate 500 cells in bronchoalveolar lavage fluid (BALF), excluding epithelial cells. The average frequency of each type of cell in the BALF of the elderly asthmatics was 65.7% for macrophages, 15.5% for lymphocytes, 8.9% for neutrophils and 9.5% for eosinophils. In the younger asthmatics the average frequency was 61.8% for macrophages, 17.1% for lymphocytes, 4.1% for neutrophils and 16.1% for eosinophils. A significant increase in the frequency of neutrophils in BALF of the elderly cases was observed in steroid-dependent intractable asthmatics compared to the younger cases (p less than 0.05). An increase in frequency of eosinophils in the younger cases was also observed, although the difference in the frequency was not significant between the elderly and the younger intractable cases. A significant difference in the frequency of each type of cell in the clinical type of bronchial asthma was not present between the elderly and the younger cases. However, the frequency of neutrophils in elderly cases was significantly increased in Ib. bronchospasm + hypersecretion type compared to Ia. bronchospasm type (p less than 0.05), and was more elevated in II. bronchiolar obstruction type (p less than 0.01). The frequency of neutrophils was markedly more increased in the elderly cases with poor prognosis than in the younger cases (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[A case of the right subclavian artery as the last branch of the aortic arch in the human fetus and a new classification on these variations].

An anomalous case of the right subclavian artery arising from the aortic arch as the last branch, in which the first branch was the right common carotid, the second the left common carotid and the third the left subclavian artery, was found in a 10 months human fetus among 173 fetuses. The right subclavian artery arose from the posterior wall of the aortic arch at the level of the Th4 and passed obliquely between the esophagus and the thoracic vertebrae. The right and the left vertebral arteries arising from the subclavian arteries on the same side entered the transverse foramen of the C6 of each side. This case belonged to type G of Adachi's classification and as well type 5 of Holzapfel's. The present authors wish to offer a new trial classification on these variations, including the origins and numbers of the vertebral arteries, by investigating many original reports in Japanese, as follows: 1) A new classification is fixed on the basis of the type G and H of Adachi-Williams et al.-Nakagawa in the classification of the branching types of the aortic arch. The type G represents that the right common carotid, the left common carotid, the left subclavian and the right subclavian arteries arise from the aortic arch in this order. The type H represents that the bicarotid trunk, the left subclavian and the right subclavian arteries arise from the aortic arch. 2) When the left vertebral artery arising from the aortic arch is found in the type G and H, "C" is prefixed G or H, as type CG, type CH. 3) When the right vertebral artery arising from the right common carotid artery is found, a prime mark, ""', is put on G or H, as type G', type H'. 4) In order to represent a compound type of the above 2) and 3), both "C" and ""' are put, as type CG', type CH'. 5) When the bilateral vertebral arteries arising from the respective subclavian artery are found in the above 2), 3) and 4) "2" postfixed "C" and the prime mark ""', as type G'2, type C2G, type CG'2, type C2G', type C2G'2, type H'2, type C2H, type CH'2, type C2H', type C2H'2. According to the above new classification, Adachi's type G can be arranged into 18 branching types. This classification may be helpful and sufficient to provide more than 100 cases of the type G and H reported on Japanese.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Rat liver cytosolic hydroxysteroid sulfotransferase (sulfotransferase a) catalyzing the formation of reactive sulfate esters from carcinogenic polycyclic hydroxymethylarenes.

Female rat liver cytosol contained at least three sulfotransferases (STs) that were separable on a DEAE-Sephadex A-50 column and transformed the carcinogen 5-hydroxymethylchrysene (5-HCR) to the potent mutagen 5-HCR sulfate. The STs also catalyzed sulfation of dehydroepiandrosterone (DHA), a typical substrate for hydroxysteroid STs. Of these three isozymes, the one (STa) with the highest 5-HCR-sulfating activity was isolated and purified (100-fold) as a homogeneous protein, in 15% yield, by successive column chromatography on agarose modified with 3'-phosphoadenosine 5'-phosphate as an affinity ligand and on Sephadex G-100. Purified STa was classified as a hydroxysteroid ST because the 5-HCR- and DHA-sulfating activities were inseparable from each other throughout the purification steps. Sulfation of 5-HCR by purified STa was competitively inhibited by DHA. STa also catalyzed sulfation of other potent carcinogens, 7-hydroxymethylbenz[a]anthracene, 7-hydroxymethyl-12-methylbenz[a]anthracene, and 7,12-dihydroxymethylbenz[a], anthrocene, to produce sulfate esters with high reactivity and mutagenicity. However, STa had no activity with 4-nitrophenol, a typical substrate for phenol STs, or with N-hydroxy-2-acetylaminofluorene. STa had a pl value of 6.4 and existed on a gel filtration column as a homooligomer of a subunit protein with Mr 30,500, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of STa was as follows: Pro-Asp-Tyr-Thr-Trp-Phe-Glu-Gly-Ile-Pro-Phe-Pro-Ala-Phe-Gly-Ile- Pro-Lys-Glu-Thr-. Immunoblot analysis of female and male rat liver cytosol, carried out by using rabbit antiserum raised against the purified enzyme STa and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicated that the female liver contained a much higher level of the enzyme than did the male liver. The marked sex difference in STa level was in good accordance with the previous demonstration that cytosol from the liver of female rats catalyzed sulfation of 5-HCR to a greater extent than did cytosol from the liver of male rats.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1990

Relationship between lipase and esterase.

There are at least two sites on the lipase which are concerned with catalysis: the catalytic site and the hydrophobic recognition site (lipid-binding site). The recognition site may be destroyed by mild proteolytic digestion, but the catalytic site may not be changed by this treatment. Mild treatment with trypsin caused change in the catalytic properties of hepatic triglyceride lipase; the water-insoluble ester-hydrolyzing activity of hepatic triglyceride lipase decreased, whereas the water-soluble ester-hydrolyzing activity did not change. After proteolytic digestion, hepatic triglyceride lipase resembles esterase since it hydrolyzes the water-soluble substrate better than the water-insoluble substrate. Conversely, esterase was converted to lipase by treatment with phospholipid. Cardiolipin in a concentration-dependent fashion enhanced triolein-hydrolysis of human serum carboxylesterase and this effect was associated with a dose-dependent decrease in water-soluble tributyrin hydrolysis. Based on these results, we propose the hypothesis that lipase and esterase have similar catalytic sites and that addition of a hydrophobic recognition site to esterase causes conversion of esterase to lipase (Fig. 9).

Animals↗
PubMed1990

[Relationship between molecular structure of halogenated methane compounds and their hypotensive effect in rats].

In this study gases of twelve halogenated methane compounds were administered by inspiration to Wistar rats in order to elucidate the relationship between molecular structure of the compounds and their hypotensive effect, and to develop new inhalational circulatory control agents. The correlation between the hypotensive effect of the compounds evaluated from the experimental data and computed van der Waals volume as well as surface area following molecular mechanics calculations of structure and energy, was investigated. The results showed that the compounds with van der Waals volume and surface area more than 73 A3 and 100 A2, respectively, had the hypotensive effect. In conclusion, our data suggest that the hypotensive effect of inhalational agents requires greater molecular sizes than regular ones.

Administration, Inhalation↗
PubMed1990

Effect of bile salts on the interfacial inactivation of pancreatic carboxylester lipase.

Pig pancreatic carboxylester lipase (cholesterol esterase, E.C. 3.1.1.13) was inactivated at a tributyrin/water interface. The apparent rate constant for inactivation increased with increase in the particle surface area of the tributyrin emulsion. The large energy of activation and entropy change for inactivation (33.7 Kcal.mol-1 and 35.8 cal.mol-1.deg-1, using 5 mM sonicated tributyrin at 37 degrees C, respectively) suggest that the observed inactivation reflects denaturation of the enzyme at the tributyrin/water interface. Bile salts protected the enzyme from irreversible inactivation at the tributyrin/water interface. The protection by bile salts was related both to their concentration and to the tributyrin concentration (substrate surface area). The protection by bile salts was not related to their concentration below or above their critical micellar concentration; the binding of bile salts to enzyme was probably the dominant protection factor. Similar stabilization was observed with other detergents such as Brij-35, Triton X-100, and sodium dodecyl sulfate. These results suggest that inactivation of carboxylester lipase occurs at a high-energy lipid-water interface and that an important role of bile salts in vivo is to stabilize carboxylester lipase at interfaces.

Animals↗
PubMed1989

A case of biliary cystadenocarcinoma with morphologic and histochemical features of hepatocytes.

A case of biliary cystadenocarcinoma is presented in which the lesion seemed to partially differentiate into hepatocellular carcinoma. This patient had a cystic tumor in the left lobe of the liver, the interior being filled with papillary tumors. Histologic examination disclosed papillary growth of columnar tumor cells, together with tumor cells akin to hepatocytes (they had a distinct cell boundary, nuclear membrane, and nucleolus) showing a cobblestone appearance in some areas. Electron microscopic examination of this area showed bile canalicular structures. Histochemically, the tissue stained positively with the Luna-Ishak canalicular (LIC) technique; periodic acid-Schiff (PAS) staining demonstrated coexisting glycogen granulo-positive cells and mucus-producing cells. Thus, in this biliary cystadenocarcinoma, some tumor cells demonstrated the morphologic and histochemical features of hepatocytes.

Aged↗
PubMed1989

Sulphotransferase-mediated activation of the carcinogen 5-hydroxymethyl-chrysene. Species and sex differences in tissue distribution of the enzyme activity and a possible participation of hydroxysteroid sulphotransferases.

Sulphation of the carcinogen 5-hydroxymethyl-chrysene (5-HCR) to the active metabolite 5-HCR sulphate occurred at significant rates in all of hepatic cytosols prepared from the male and female experimental animals, rats, mice, guinea-pigs and hamsters. The 5-HCR-sulphating activity was also found in kidney cytosols of all the experimental animals used, while their activities were much less than those of hepatic cytosols. In the male mice, the enzyme activity of testis was higher than any other examined tissue. Small intestine and adrenal of male and female guinea-pigs had relatively high enzyme activities. Small enzyme activities were also found in a variety of extrahepatic tissues of some of these animals. Marked species and sex differences (female much greater than male in the rat and mouse) were observed in the hepatic enzyme activity. In the female rat liver which showed the highest 5-HCR-sulphating activity among the examined tissues of all the animals, a typical hydroxysteroid sulphotransferase inhibitor, dehydroepiandrosterone (DHA) sulphate (1 mM), potently and competitively inhibited the sulphation of 5-HCR as well as that of DHA, a typical substrate for hydroxysteroid sulphotransferases. On the contrary, the phenol sulphotransferase inhibitors, pentachlorophenol and 2,6-dichloro-4-nitrophenol, had only a little effect on these enzyme activities even at a concentration of 50 microM that showed a potent inhibition of the phenol sulphotransferase activity. These results suggest that 5-HCR be sulphated in the female rat liver by hydroxysteroid sulphotransferases, but not by phenol sulphotransferases.

Animals↗
PubMed1989

Toxicity to medaka of solutions of fenitrothion degraded by strong alkali.

Various experiments were conducted to examine the effects of degradation products on organisms. Fenitrothion (MEP) emulsions adjusted to pH 10 or 14 were degraded by exposure to natural sunlight in winter with heat. Medaka eggs were exposed to various concentrations of the degraded solutions and an untreated MEP emulsion for 5 days starting 4-5 h following fertilisation. The eggs were then allowed to develop in dechlorinated tap water until the fish reached 3 months of age. The hatching rate and rate of survival in the degraded solutions tended to be lower than those in the untreated MEP emulsion, and the incidence of abnormal fry in the degraded solutions was higher than that of the untreated MEP emulsion. It thus appears that degradation products formed by MEP have toxic effects on medaka.

Journal Article↗
PubMed1989

Effects of active compounds isolated from Angelica shikokiana on lipid metabolism in fat cells.

It was found that the EtO Ac fraction of the roots of Angelica shikokiana inhibited adrenaline-induced lipolysis in rat fat cells, while having no effect on ACTH-induced lipolysis. On the other hand, the MeOH fraction was found to inhibit ACTH-induced lipolysis but not to inhibit adrenaline-induced lipolysis. The active substances isolated from this root were elucidated to be psoralen (I), bergapten (II), isopteryxin(3'-angeloyloxy-4'-acetoxy-3',4'-dihydroseseli n) (III) and 3'-epoxyangeloyloxy-4'-acetoxy-3',4'-dihydroseselin (IV), respectively. The two furocoumarins, psoralen and bergapten, were found to enhance ACTH- and adrenaline-induced lipolysis in fat cells respectively. In contrast, a coumarin derivative of khellactone type, isopteryxin (III), was found to inhibit the adrenaline-induced lipolysis but with no effect on ACTH-induced lipolysis and insulin-induced lipogenesis from glucose. The other coumarin of khellactone type, 3'(R), 4'(R)-3'-epoxyangeloyloxy-4'-acetoxy-3',4'-dihydroseseline (IV), was found to inhibit the insulin-induced lipogenesis from glucose but it had no effect on adrenaline- and ACTH-induced lipolysis.

5-Methoxypsoralen↗
PubMed1989

Immunoglobulin classes of antibody for human T-lymphotropic virus type-I (HTLV-I) in healthy donors and HTLV-I-associated disorders.

Healthy blood donors, patients with adult T-cell leukemia (ATL) and HTLV-I-associated myelopathy (HAM) and recipients of unscreened blood (SR) who had seroconverted and were followed-up for more than 2 years were examined for HTLV-I antibodies of immunoglobulin G (IgG) and M(IgM) classes. The overall infection rate in donors was 4.9%, as determined by screening with a particle agglutination method (PA). The rate increased with increasing age. Positive sera with a low titer in the PA test (1/16, 1/32 and 1/64) contained IgM antibodies in 32.5% (titer 1/16) to 36.1% (titer 1/64) of the cases, but IgG antibodies were detected in only 5.6% of the sera with a titer of 1/16 and in 36.1% of the sera with a titer of 1/64. Conversely, in high titer sera (1/128 or higher) IgG antibodies were almost always detectable (99.0%) and IgM antibodies less frequently (25.5%). Sera from acute, chronic and pre-ATL, HAM and SR patients contained IgG antibodies in high titer in all cases. The incidence of IgM antibodies was 7.7, 30.0, 53.3, 72.3, and 77.8%, respectively. IgM antibodies were demonstrated repeatedly in some cases who were followed up for a year. Only IgM antibodies from HAM patients occurred in high titers and had strong reactivity to the p24 antigens of HTLV-I in Western blot testing. It is concluded that it is important to detect IgM antibodies not only in primary infections but also in persistent infections of HTLV-I.

Adolescent↗
PubMed1989

Kindling of the visual cortex in cats: comparison with amygdaloid kindling.

Kindling of the primary visual cortex (VC) was compared with that of the amygdala in cats. VC kindling was basically similar to kindling of the amygdala in that daily electrical stimulation can lead to the development of a generalized convulsion in most subjects, a growth of afterdischarges in their configuration and duration, and a reduction of the afterdischarge threshold. The kindling response of the VC differed from that of the amygdala in a number of respects, i.e., a high afterdischarge threshold, a different pattern of behavioral seizure development, an abrupt growth of electroclinical seizures coincident with the onset of a generalized convulsion, an intersubject variability in seizure susceptibility, and a marked seizure instability. In VC kindling the afterdischarge propagation into the amygdala was not observed until the generalized convulsion developed, and the early involvement of afterdischarge was seen in the pulvinar, lateral geniculate body, and superior colliculus. These data suggest that a neural mechanism different from amygdaloid kindling may participate in VC kindling, and that the subcortical structures of the visual system are involved in the preferential pathway for a seizure generalization from the VC.

Amygdala↗