Biomedical subjects
H Kitano
Publications and source records attributed to H Kitano.
The relationship between vasopressin and endolymphatic hydrops in the guinea pig.
Clinical studies have shown that plasma vasopressin level is significantly elevated in patients with Meniere's disease. Other reports indicated that histamine induced a very quick and high elevation of vasopressin level and caused nystagmus in experimentally produced endolymphatic hydrops. We became interested in further investigating the details of this relationship by studying the effect of experimental endolymphatic hydrops and histamine upon plasma vasopressin level in the guinea pig. The results are as follows: 1) Histamine increased the plasma vasopressin level in normal guinea pigs. 2) There was no statistically significant difference in the plasma vasopressin level between the hydrops model and normal guinea pigs. 3) Histamine increased the plasma vasopressin level more in the hydrops model group than in normals. 4) Plasma vasopressin level was elevated in the vertiginous model caused by inner ear anesthesia. Our results support those of clinical investigators who reported that the plasma vasopressin level was elevated more in the Meniere's disease group than any other equilibrium disorder group. It is possible that vasopressin is in someway involved in the development of endolymphatic hydrops.
[Structure and diversity of yeast mitochondrial genomes].
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Effect of alcohol on the endotoxin binding protein produced in the liver.
The Kupffer cell-hepatocyte interaction in the process of endotoxin clearance and the effect of alcohol on it were investigated in a newly developed rat Kupffer cell-hepatocyte culture system. The hepatic production of endotoxin binding protein was increased when the Kupffer cells were preincubated in the medium containing ethanol, and the resultant culture supernatant was added to the hepatocyte culture system. The amount of endotoxin binding protein produced by the hepatocytes was increased as the ethanol concentration in the culture medium of Kupffer cells was increased. This endotoxin binding protein was proved to enhance the uptake of endotoxin and suppressed the production of tumor necrosis factor in the Kupffer cells. When Kupffer cells and hepatocytes were isolated from chronically alcohol-fed rats, further addition of ethanol to the culture medium of Kupffer cells did not affect the hepatic production of endotoxin binding protein. The increase in hepatic production of endotoxin binding protein may serve as a defence mechanism against endotoxicity. There is a possibility that an impairment of the defence mechanism has a pivotal role in the development of endotoxemia and endotoxicity in chronic alcoholics.
[Effect of high dose nicardipine in patients with ruptured cerebral aneurysm].
We studied the effect of high dose nicardipine in patients with ruptured cerebral aneurysm. Seventeen patients were treated with intravenous infusion of nicardipine, 23.0-124.4 mg/day, for 15 days, which was started within 72 hours after onset of subarachnoid hemorrhage (SAH). Aneurysmal neck was clipped within 96 hours after SAH. Five patients were excluded because of discontinuation of treatment due to hypotension and intra- or postoperative complication. Among the 12 patients, symptomatic vasospasm was observed in 6, and one of them had a permanent deficit. Severe angiographic vasospasm was observed in 3 patients, but two of them did not show symptomatic vasospasm. From this study we can't draw any conclusion about effect of nicardipine on prevention of symptomatic and angiographic vasospasm after SAH, because of small number of cases.
Metabolic fate of endotoxin and blood tumour necrosis factor levels in rats with acute and chronic alcohol loading.
To investigate the metabolic fate of endotoxin in alcoholics and its possible relationship to cytokines and liver injury, we administered a low-dose radiolabelled endotoxin to rats given alcohol in various conditions and studied the organ distribution of endotoxin and measured plasma levels of tumour necrosis factor (TNF). In the chronic alcohol-fed rats (Lieber-DeCarli liquid diets for 6 weeks) 3H-endotoxin was rapidly cleared by the liver and excreted into faeces. However, the endotoxin clearance was decreased after an acute ethanol load to rats (5 mg/g body wt ethanol i.p.) or in the chronic ethanol-fed rats with an additional 5 mg/g body wt ethanol load. Plasma TNF was not elevated in the control or in the acute ethanol load rats, slightly elevated in the chronic ethanol-fed rats and markedly elevated in the chronic ethanol-fed rats with an additional high-dose ethanol load. Serum GPT was elevated only in the chronic ethanol-fed rats with an additional high-dose ethanol. In conclusion, an additional administration of a high dose ethanol to chronic alcohol-fed rats led to decrease of endotoxin clearance and elevation of plasma TNF, which may play an important role in the pathogenesis of alcoholic hepatitis.
Effect of alcohol on the functions of Kupffer cells and splenic macrophages in rats.
Uptake of endotoxin and production of tumor necrosis factor (TNF) by Kupffer cells and splenic macrophages were measured in chronically alcohol-fed rats. Twenty male Sprague-Dawley rats, weighing 200-250 g, were pair-fed by isocaloric control and ethanol-containing Lieber-DeCarli liquid diets for 6 weeks. Endotoxin uptake and TNF production of Kupffer cells and splenic macrophages in the chronic ethanol load-group were significantly (P < 0.001) greater than those in the control group. The increase in endotoxin uptake was more prominent in Kupffer cells and the increase in TNF production was more marked in splenic macrophages in the chronic ethanol group. When these cells were precultured in the medium containing 10-100 mM ethanol, the endotoxin uptake and TNF production of Kupffer cells isolated from control and chronic ethanol-fed rats were decreased in proportion to the concentration of ethanol in the culture medium. However, the addition of ethanol to the culture medium did not affect the endotoxin uptake and TNF production of splenic macrophages. These results support the hypothesis that the splenic macrophages are important for endotoxin uptake, and excessive production of TNF in rats given large amounts of alcohol.
Inhibition by squalene of the tumor-promoting activity of 12-O-tetradecanoylphorbol-13-acetate in mouse-skin carcinogenesis.
Squalene inhibited the effect of tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA), such as increased 32Pi incorporation into phospholipids of HeLa cell membrane, induction of Epstein-Barr-virus early antigen in Raji cell and induction of ornithine decarboxylase in mouse skin. Squalene also markedly suppressed the promoting activity of TPA on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice.
Potent preventive action of alpha-carotene against carcinogenesis: spontaneous liver carcinogenesis and promoting stage of lung and skin carcinogenesis in mice are suppressed more effectively by alpha-carotene than by beta-carotene.
Although beta-carotene has been considered to be a key cancer preventive agent in green and yellow vegetables, other types of carotenoids, such as alpha-carotene, may also contribute to anticarcinogenic action, since these carotenoids usually coexist with beta-carotene and are detectable in human blood and tissues. In this study, we compared the inhibitory effect of natural alpha-carotene, obtained from palm oil, with that of beta-carotene on spontaneous liver carcinogenesis in C3H/He male mice. The mean number of hepatomas per mouse was significantly decreased by alpha-carotene supplementation (per os administration in drinking water at a concentration of 0.05%, ad libitum) as compared with that in the control group (P < 0.001, Student's t test). On the other hand, beta-carotene, at the same dose as alpha-carotene, did not show any such significant difference from the control group. Furthermore, we also compared the antitumor-promoting activity of alpha-carotene with that of beta-carotene against two-stage mouse lung carcinogenesis (initiator, 4-nitroquinoline 1-oxide; promoter, glycerol). alpha-Carotene, but not beta-carotene, reduced the number of lung tumors per mouse to about 30% of that in the control group (P < 0.001, Student's t test). The higher potency of the antitumor-promoting action of alpha-carotene compared to beta-carotene was confirmed in other experimental systems; e.g., alpha-carotene was also found to have a stronger effect than beta-carotene in suppressing the promoting activity of 12-O-tetradecanoylphorbol-13-acetate on skin carcinogenesis in 7,12-dimethylbenz[a]anthracene-initiated mice. These results suggest that not only beta-carotene, but also other types of carotenoids, such as alpha-carotene, may play an important role in cancer prevention.
D-galactosamine-induced cell damage enhances specific binding of prostaglandin E1 to rat hepatocytes.
Specific bindings of [3H]prostaglandin E1 ([3H]PGE1), 125I-glucagon and [3H]norepinephrine to D-galactosamine (GalN)-treated rat hepatocytes in primary culture were investigated. After a two hour-treatment with GalN (1 and 10mg/ml), hepatocytes showed an enhanced specific binding to [3H]PGE1, whereas 125I-glucagon binding was little affected and [3H]norepinephrine binding was strongly diminished. Scatchard plot analysis indicated an increase of binding sites of [3H]PGE1. This unusual manner of [3H]PGE1 binding is suggested to indicate a special property of PGE1 receptor and may be associated with the cytoprotective effect of prostaglandins.
Mutual recognition between polymerized liposomes. IV. Polysaccharide-lectin system.
As a model of cell-cell recognition processes, the association processes of a polysaccharide (mannan)-carrying liposome with a lectin (Concanavalin A, Con A)-carrying polymerized liposome were followed by turbidimetry. The association process was strongly inhibited by the addition of a low molecular weight sugar, methyl-alpha-D-mannopyranoside, which shows that the association between the liposomes is due to the specific interaction between Con A and mannan. The association rate constant obtained was much smaller than the theoretical value for a diffusion-controlled binary association process. This implies that the association rate of liposomes is limited by the recognition between complementary ligands bound on the liposome surfaces. Another reason for the smaller association rate constant in the liposome-liposome system is the repulsive hydration effect. The effect of the surface density of the lectin immobilized on the liposome on the recognition was also examined.
Abscess within a glioblastoma multiforme--case report.
A rare case of abscess within a glioblastoma with an unusual presentation occurred in a 46-year-old female who developed right hemiparesis and seizure. Computed tomography and magnetic resonance imaging demonstrated hemorrhage which mimicked hemorrhagic infarction. However, the lesions developed ring enhancement. Aspiration showed one to be an abscess, which collapsed by drainage but later re-expanded. The mass was removed, and histological examination revealed glioblastoma.
Anticancer gelatin microspheres with multiple functions.
Biodegradable, hydrophilic gelatin microspheres (GM) with an average diameter of 70 microns were prepared by cross-linking gelatin with glutaraldehyde for hepatic intra-arterial infusion. An anticancer agent, mitomycin C (MMC), together with a radioisotope, 131I, were bound to the GM for chemotherapy and local internal radiotherapy. The 131I-labelled MMC-GM (131I-MMC-GM) could accumulate in the specific site and embolize the hepatic arteries after the hepatic intra-arterial infusion, while it caused various effects to the liver cells. The 131I-MMC-GM remained within the hepatic arteries for at least one month. In vitro release of drugs from the GM was also quantified using a dynamic dialysis method.
Mutual recognition between polymerized liposomes. III. Association processes between avidin and biotin on polymerized liposome surfaces.
Association processes between avidin and biotin in various liposome systems were studied. By incorporating biotin onto the polymerized liposome surface, association processes with free avidin were largely decelerated. When the number of binding sites on the liposome surface was taken into account, the corrected association rate constant was 4.3% of the theoretical value for binary collision. The association rate constant between avidin- and biotin-carrying polymerized liposomes was much smaller than those for both the free avidin-free biotin system and the free avidin/biotin-liposome system, probably due to the repulsive hydration phenomenon. The results are discussed both in terms of our understanding of cell-cell recognition phenomena and for the development of drug delivery systems.
Effect of anoxia on spontaneous discharges of the cochlear single unit in guinea pigs.
The present experiment examined the effect of anoxia on the spontaneous discharges of cochlear single units in guinea pigs; several additional animals were tested for the combined effect of anoxia and sodium salicylate. Following the induction of anoxia, initial increases in the number of spontaneous discharges were seen in 19 of the 34 cochlear single units tested. Neurons showing high frequencies during normal respiration tended toward increased rates of discharge during anoxia. In the 5 animals pretreated with sodium salicylate, remarkable increases in the spike rates were noted following the induction of anoxia.
Direct examination of chemical kinetic laws by visual imagery. IV. Association processes between antigen- and fragmented antibody carrying fluorescent latex particles.
The binary association process was further examined by direct visual observation using a fluorescence microscope connected to an image-processing system and by a spectrophotometric method. In the present paper, we used human serum albumin (HSA)- and fragmented anti-HSA antibody-carrying fluorescent latex particles in order to attain higher sensitivities and exclude complexities that might be caused by dissociation of the association product. The rate constant of the binary association process was estimated to be 6.0 x 10(8) M-1 s-1 at 30 degrees C and pH 7.6. The activation parameters of the association process were evaluated. The effects of pH and viscosity of the suspension on the association process were also examined.
Kinetic study of the effects of solvation on the dimerization process of alpha-chymotrypsin.
The dimeric association process of alpha-chymotrypsin has been studied with the aid of a stopped-flow spectrophotometer at various temperatures and pH values. From the temperature dependences of the forward reaction rate constant (kf) and the equilibrium dimerization constant (KD), the reaction system observed here is concluded to be entropy-driven. The increase in entropy can be attributed to the release of water molecules from both the active site and the surface part of the protein molecule during the course of dimerization. From the pH dependences of the reaction rate constants and the equilibrium constant, the reaction is concluded to depend strongly on the dissociations of the site between the carboxyl group of the aspartic acid and imidazolyl group of the histidine residues (in the higher pH region), and the site between the imidazolyl group of the histidine and the carboxyl group of the tyrosine residue (in the lower pH region), respectively.