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Biomedical subjects

K Kono

Publications and source records attributed to K Kono.

At least 199 records · Page 11Linked to original sources
PubMed1988

Postsynaptic arch in the frog neuromuscular junction: paramembranous protuberances coating the inner surface of the postjunctional membrane.

The frog neuromuscular junction was fixed and processed for electron microscopy according to the method of rapid freezing followed by freeze-substitution. The synaptic structures, including cleft material, paramembranous cytoplasmic coating on the postsynaptic membrane, and subsynaptic cytoplasmic elements, were examined in thin sections. The basal lamina, about 50 nm thick, was seen to bisect a synaptic cleft approximately 100 nm wide. The lamina consists of two parts: the central dense line and the fine filaments protruding from it in the direction of the apposing postjunctional membrane. Present on the cytoplasmic surface of the postjunctional membrane are electron-dense protuberances, 41 +/- 5 nm in width and 27 +/- 5 nm in height (top to membrane centre). They are arranged in regular parallel rows, at 54 +/- 4 nm intervals (centre to centre). The paramembranous protuberance coats the inner surface of the postjunctional membrane at its apex as well as at the middle portion of the junctional process, pointing to its probable hairpin-like course in a transverse plane of the process. From its location and three-dimensional arrangement, this protuberance was termed the 'postsynaptic arch'. A filamentous meshwork is present just beneath the postjunctional membrane and extends into the cell interior. The submembranous meshwork appears to connect to the underlying bundles of cytoskeletal filaments. The possibility is discussed that the postsynaptic, electron-dense arch corresponds to the 43-kDa protein, a major alkaline-extractable protein thought to be associated with the cholinergic receptor molecules in the postsynaptic membrane.

Animals↗
PubMed1988

Serum zinc and copper changes after gastrectomy in aged patients with gastric cancer.

Serum zinc and copper levels were evaluated in patients with gastric cancer who had undergone gastrectomy. These patients were divided into two age categories; namely, the aged group, comprising 39 patients over the age of 70 years, and the younger group, comprising 23 patients younger than 50 years. The data before and after surgery were compared between the two groups. Serum zinc levels in the aged group were significantly lower than those in the younger group, both before and after surgery. Serum copper levels, however, did not differ significantly between the two groups. The serum Cu/Zn ratio was also analyzed according to the histological stages of cancer (stages I to IV), and compared between the two age-classified groups. The aged group showed a higher Cu/Zn ratio at all stages, whereas in the younger group, the ratio was significantly higher at stage IV than in the earlier stages. Preoperative serum zinc, copper, and the Cu/Zn ratio were studied in relation to the complication of anastomotic leak after surgery. The Cu/Zn ratio in the aged patients with this complication was significantly higher than that in the aged patients without it. These results suggest that the Cu/Zn ratio may be an important factor in determining nutritional parameters in the aged.

Adult↗
PubMed1988

Experimental portal fibrosis produced by intraportal injection of killed nonpathogenic Escherichia coli in rabbits.

An attempt was made to develop an animal model for the study of the etiology of noncirrhotic portal fibrosis or idiopathic portal hypertension based on the assumption that it is related to chronic abdominal infection. Rabbits were given killed nonpathogenic Escherichia coli intraportally or intravenously. The animals to which a mixture of killed E. coli and rabbit antiserum (aggregated E. coli) was given intraportally developed remarkable histologic changes in the liver. The early inflammatory reactions in the portal area and parenchyma were followed by rapid disappearance of inflammation and development of portal fibrosis with bile duct proliferation. Three intraportal challenges with aggregated E. coli were sufficient to produce pronounced portal fibrosis, although there was considerable variation in response among individual animals. This procedure also produced splenomegaly, and in some animals marked portal hypertension. Injection of nonaggregated killed E. coli into the portal vein or aggregated E. coli into the ear vein also caused similar hepatic changes, but they were milder in degree. These histologic changes resemble portal fibrosis seen in idiopathic portal hypertension and, less closely, pericholangitis associated with inflammatory bowel disease in humans.

Animals↗
PubMed1988

Cholesterol metabolism in inherently scorbutic rats (ODS rats).

We observed the cholesterol metabolism of a colony of Wistar rats with a hereditary defect in vitamin C synthesizing ability (the ODS (osteogenic disorder-Shionogi) rats) in six kinds of experiments. Female ODS rats aged 36 days had a low HDL (high-density lipoprotein)-cholesterol level in serum as compared with age-matched control rats in spite of the absence of scorbutic symptoms. Female ODS rats aged 63 days which revealed severe scorbutic symptoms had a very low HDL-cholesterol level (mean value; 17 mg/dl). And male ODS rats, whose lives had been prolonged by supplementing with L-ascorbic acid, also had lower serum HDL-cholesterol and had increased total cholesterol in serum and liver when the acid supplement dose was relatively insufficient. On the other hand, we examined HDL2- and HDL3-cholesterol levels in serum to determine the mechanism of low HDL-cholesterol. As a result, we observed a low HDL2-cholesterol level in ODS rats but normal HDL3-cholesterol level. But the authors observed no decrease of LCAT (lecithin: cholesterol acyltransferase) activity in serum of ODS rats. These results could be due to disturbance of lipid metabolism in a vitamin C-deficient condition, that is to say, there might be abnormalities of the cholesterol excretion pathway of bile acid from liver, and maturity of the HDL-cholesterol particle due to other factors except that of LCAT activity.

Animals↗
PubMed1988

[Hyperfunctioning follicular carcinoma of the thyroid. A case report].

A 76-year-old female patient with a large neck lump of 15-year duration, was accompanied by palpitation and tremor. The lump was 9 x 5cm in size and the lower half of it was not palpable because the lower pole was located in the mediastinum. Physical examination revealed two enlarged lymph nodes in the right supraclavicular area. Chest X-ray film showed a coin lesion in the right lung that seemed to be a metastasis. The patient was apparently thyrotoxic with elevated serum concentrations of 15.7 micrograms/dl thyroxin and 359 ng/dl triiodothyronine. A neck scintigraphy using 123Iodine showed a thyroid hot nodule in accordance with this lesion. A total thyroidectomy with a modified neck dissection was carried out. This was followed by 131Iodine therapy. Specimen of the primary lesion weighed 147 g. Pathology of this tumor was follicular carcinoma of the thyroid. The patient was doing well 14 months after surgery. In the literature, three cases of similar hyperfunctioning thyroid carcinoma have been reported, all of which had a large primary lesion. The histological features proved to be of follicular or papillofollicular type. The treatment in these cases was administration of an antithyroid drug followed by surgical removal.

Adenocarcinoma↗
PubMed1987

Urinary fluoride monitoring of industrial hydrofluoric acid exposure.

Preworkshift and postworkshift urinary fluoride concentrations were measured in 142 hydrofluoric acid (HF) workers and 82 unexposed workers aged 18 to 59. Postshift urinary fluoride concentration in HF workers was significantly higher than that in preshift or control workers. A linear relationship was observed between the mean values in urinary fluoride concentration and the HF concentration in the air. The mean urinary fluoride concentration of 4 ppm and its lower fiducial limit (95%, P = 0.05) of 2 ppm (specific gravity 1.024) were estimated corresponding to the atmospheric HF concentration of 3 ppm, which is the maximal allowable concentration recommended by the Japanese Association of Industrial Health and also the threshold limit value suggested by the American Conference of Governmental Industrial Hygienists. The results suggest that exposure to HF can be monitored by determining the urinary fluoride concentration.

Adolescent↗
PubMed1987

Risk factors of atherogenicity in inherently scorbutic rats (OD rats).

We observed the pathophysiological state of a colony of Wistar rats with a hereditary defect in vitamin C-synthesizing ability (the OD rat) in three kinds of experiments. In experiment 1, OD rats that were not supplemented with L-ascorbic acid (ASA) were killed 36 days after birth. In experiment 2, OD rats that were not supplemented with AsA were killed 63 days after birth. In experiment 3, OD rats that were supplemented with sufficient ASA (100 mg/100 g body weight/day) for 16 days from 47 days after birth were assayed 63 days after birth. From analyses of serum chemistry, platelet aggregability and counts of blood cells, some atherogenic risk factors were elucidated, that is, there was a decrease of high density lipoprotein in serum and an increase of platelet aggregability. Furthermore, it was observed that OD rats have some characteristics different from latent vitamin C-deficient animals from the viewpoint of malnutrition.

Alanine Transaminase↗
PubMed1986

Effect of intrahepatic arterial infusion of 131I-labelled lipiodol on hepatocellular carcinoma of rat.

Intrahepatic arterial infusion of 131I-labelled lipiodol was performed to study the intrahepatic distribution of lipiodol and to determine the radiation effect on 3'-Methyl-4-Dimethylaminobenzene (DAB) induced hepatocellular carcinoma (HCC) in rats. From the findings of the softex films and scintigrams of the liver, according to the time course, lipiodol was found to accumulate in the tumour tissues parallel with the degree of perfusion, and it remained in the tumour tissues for an extended period probably due to the delay of the degradation of lipiodol compared to that in non tumour tissues. It was noticed that the lipiodol, accumulated and deposited selectively in the tumour tissues, existed mostly in the extracellular space but not in the intracellular space. In histological studies of the resected specimens of the tumours, complete necrosis of hepatocellular carcinoma was recognized 2 to 8 weeks after the infusion of 131I-labelled lipiodol, while there was none in the control group where cold lipiodol was employed. These results suggest that the most effect on hepatocellular carcinoma in this study is caused by the radiation effect of 131I-labelled lipiodol.

Animals↗