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Biomedical subjects

T Nonaka

Publications and source records attributed to T Nonaka.

At least 127 records · Page 7Linked to original sources
PubMed1989

Ultrasonically guided percutaneous ethanol injection therapy for hepatocellular carcinoma.

Ultrasonically guided percutaneous ethanol injection therapy (US-PEIT) was performed in 26 patients with hepatocellular carcinomas (HCC) in whom neither surgery nor transcatheter arterial embolization (TAE) was indicated, or TAE had proved ineffective. Comparison of results by various diagnostic imaging techniques with histopathological findings revealed that tumor necrosis after US-PEIT was correlated with increased echogenicity of the tumor by US, decreased density of the tumor and disappearance of contrast enhancement by computed tomography (CT), and change to a lower signal in the tumor by magnetic resonance imaging [MRI, 0.15 T permanent magnet, spin-echo sequence, repetition time (TR)/echo time (TE) = 2000/80 ms]. Thus, findings by imaging are useful in evaluating the initial effect of US-PEIT. Of three specimens obtained by liver resection and three obtained at autopsy, four showed complete necrosis after US-PEIT (maximum tumor diameter, 3 cm). This method also appeared to be effective in cases of capsular invasion. In this study, the 2-yr survival rate of patients with HCC was 75%. Although this study was not a controlled clinical trial, we conclude that US-PEIT may be a potentially effective treatment for HCC.

Administration, Cutaneous↗
PubMed1988

Phenotypic expression of photoreceptor and endocrine cell properties by cultured pineal cells of the newborn rat.

Pineal glands of newborn rats were dissociated and maintained under cell culture conditions. The phenotypic expression of both photoreceptor and endocrine cell properties was investigated using immunohistochemical techniques (specific antibodies against opsin or serotonin). After one week in culture, a number of small round cells appeared on top of a sheet of flat epithelium. Among those cells, opsin-like immunoreactive cells were observed. These cells showed a neuron-like morphology with neuritic processes and often formed rosettes. Immunoreactivity was found on the plasma membrane of both the soma and cell processes. Serotonin-like immunoreactive cells were also differentiated in culture with two different morphological types of cells being found. One type resembled cultured serotonin-containing amacrine cells of the retina, and the other type had a flat, polygonal shape similar to that of pinealocytes. Both types of immunoreactive cells possessed fine neuritic processes. These results indicated that cell culture of rat pineal gland cells allowed expression of some properties, such as opsin synthesis and neuron-like morphology with long neuritic processes, that were not expressed in the intact rat pineal gland.

Animals↗
PubMed1987

[Vascular compression neuropathy of the optic nerve by sclerotic internal carotid artery].

Although mechanical compression of the optic nerve by a dilated and/or tortuous sclerotic intracranial internal carotid artery is occasionally reported as an etiology for impairment of vision and visual field, early diagnosis of such condition has been hampered by the lack of characteristic neuro-ophthalmological and neuroradiological findings. The review of 35 previously reported cases (60 eyes) including ours showed that 41% out of the 34 operated eyes were improved neurologically by the decompressive procedure, while it was in 27% out of the 26 undecompressed or non-operated eyes. These unsatisfactory operative results are considered mainly due to the failure of early diagnosis. In order to investigate the relationship between the carotid artery and optic nerve, we proposed a method of angiographical projection consisting of the straight view along the long axis of the optic canal. By this projection, it is possible to detect a supero-medial enlargement and/or dislocation of the cisternal portion of the internal carotid artery. The addition of metrizamide CT cisternography which clarifies the relationship of the optic nerve, chiasm and internal carotid artery in the supersellar cistern may further provide an useful clue for the diagnosis of this condition.

Aged↗
PubMed1984

Identification of vasopressin and determination of its corticomedullary levels in rat kidney tissue.

To investigate the kidney tissue level of arginine vasopressin (AVP), tissue AVP was extracted, identified and assayed. Rat kidney tissue was separated into the papilla (P), medulla (M), and cortex (C). After homogenization, AVP was extracted with acetone and determined by radioimmunoassay. Fractionation of the tissue extract by Sephadex G25 column chromatography showed that the peak of immunoreactive AVP was identical to that of synthetic AVP. There was good correlation between bioassayable and immunoassayable AVP for the tissue extracts. Tissue AVP concentrations (pg/g wet weight) after 36 hr of dehydration were: P, 164.3 +/- 13.0; M, 93.8 +/- 8.4; and C, 28.9 +/- 3.9 with a plasma AVP (pg/ml) of 11.7 +/- 1.0 (mean +/- SE, N = 18). Thus, the papilla/plasma AVP concentration ratio was high. When 125I-AVP was administered, the papilla/plasma ratio was very low. Under water diuresis, the tissue AVP level was very low. The kidney tissue level of dDAVP, which was administered exogenously, was much higher than that of AVP when compared at similar plasma levels. Thus, the present study demonstrated the existence of a corticomedullary concentration gradient of AVP with a medullary level much higher than the plasma level. The accumulation of AVP seemed to result from receptor-mediated processes, since 125I-AVP, which is biologically inactive and does not bind to hormone receptors, showed only a slight accumulation. The higher tissue level of dDAVP suggested that the tissue level was determined by the balance between accumulation and inactivation, since dDAVP is known to be scarcely inactivated in the kidney.

Animals↗
PubMed1984

Freeze-fracture observations of the cell walls and peribacillary substances of various mycobacteria.

Ultrastructure of the cell wall and peribacillary substances of various mycobacteria (32 strains of 18 species) grown in vitro was studied by a freeze-fracture technique. Peribacillary substances differed in shape among species and even among strains of the same species, and were classified into five types: (1) amorphous substances; (2) multi-layered sheaths with no filamentous units; (3) structures composed of filaments of 2-4 nm diameter, which were further classified into three subtypes according to the arrangement of the filaments; (4) helical fibres; and (5) single fibres, or networks of fibrous structures, with no visible substructures. No strains revealed peribacillary structures resembling those of uncultivable Mycobacterium leprae. These results have implications for the mechanism of freeze-fracturing in mycobacterial walls.

Cell Wall↗
PubMed1982

[Chemotherapy of hepatocellular carcinoma--with special reference to one-shot intra-arterial infusion of a high dose of adriamycin].

Twenty-two cases of non-operable hepatocellular carcinoma (HCC) were treated with three types of chemotherapy mainly with Adriamycin (ADM). In the group (A), one shot intraarterial infusion of 100 mg ADM into the hepatic artery (9 cases), group (B), one shot intraarterial infusion of 30 mg ADM (3 cases), and group (C), 20-60 mg of systemic administration of ADM (10 cases) were examined. The therapeutic effects and side effects were studied comparatively among these three groups. In terms of tumor regression, RR was 4 cases (44.4%), and MR was 4 (44.4%) in group (A), and PR was 1 (10%) in group (C). The average survival time was 8.3 months (5 cases are still alive) in group (A), 5.7 months in group (B), and 4.2 months in group (C), respectively As side effects, alopecia was found 100% in (A), 33% in (B); leukocytopenia was found 100% in (A), 33% in (B); but no serious complication due to leukocytopenia was observed in any of them. One shot of 100 mg of ADM intraarterial infusion therapy seemed to be superior in therapeutic effects against HCC over other therapies.

Aged↗