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Biomedical subjects

Y Mishima

Publications and source records attributed to Y Mishima.

At least 217 records · Page 12Linked to original sources
PubMed1989

[Heterogeneity of palmo-plantar malignant melanomas--comparative analysis of acral lentiginous melanoma and nodular melanoma on palm or sole].

We analysed and discussed clinico-pathologically 16 cases of malignant melanoma and 4 cases of their precancerosis occurring on the palm or sole of Japanese patients. In contrast to previous reports from the US and Europe, which emphasize the almost exclusive preponderance of acral-lentiginous melanoma (ALM) on volar skin, our series consisted of eight cases each of acral-lentiginous and nodular melanoma. We investigated the clinical and cytopathological findings of 4 representative ALM and 2 representative nodular melanomas, as well as the detailed clinical behaviour of all 16 cases, including precancerosis. In every case of ALM, we have found the presence of a three-phase pattern, namely A-(nodule phase), B-(plaque phase), and C-(macule phase) phases, representing focal and progressive melanoma genesis both clinically and pathologically. A- and B-phases of ALM shared many common features with pagetoid melanoma and pagetoid premalignant melanosis frequently occurring on the trunk. It was also found that nodular melanoma on the palm or sole also possesses common features with that occurring on non-volar areas and exhibits the highest malignancy of all melanoma types. In addition, we discussed ALM precancerous lesions called plantar premalignant melanosis, which consist of B- and C-phases only.

Adult↗
PubMed1989

[Proposal of revised criteria for malignant rheumatoid arthritis].

The diagnostic criteria for malignant rheumatoid arthritis (MRA), which was proposed by the Research Group of MRA and periarteritis nodosa supported from the Ministry of Health and Welfare has been widely used since 1973. This diagnostic criteria was established for selecting RA patients with life-threatening extraarticular manifestations caused by vasculitis. However, in practice, RA patients with extraarticular involvements related to vasculitis, as well as, cases which were not related to vasculitis were diagnosed as MRA in this criteria. Because of the aforementioned and after research, we revised the diagnostic criteria for MRA. At first, we defined MRA as RA patients having intractable and severe extraarticular manifestations by various causes including vasculitis. One hundred and sixty-nine patients with MRA and 227 patients with RA from 39 medical facilities were analysed. Sixteen extraarticular clinical manifestations and 9 laboratory findings were compared between MRA and RA patients. Comparison of specificity in each criterion for MRA was made by using the Second quantitative analysis. Thereafter, the combinations of the variables which were most specific to MRA were studied. At the same time, sensitivity and specificity for MRA were also studied. The revised criteria are as follows: A. Clinical and Laboratory Findings--(1) visceral infarction, (2) myocarditis, (3) skin ulcer or skin infarction, (4) episcleritis or iritis, (5) polyneuritis, (6) high titers of rheumatoid factor, (7) immune complexes or low complement levels, (8) subcutaneous nodule, (9) pleuritis or pericarditis, (10) interstitial pneumonitis or lung fibrosis. B. Histopathological Findings from Biopsy Specimens--necrotizing vasculitis and/or granulomatous vasculitis and/or endoarteritis obliterans in small and/or medium size arteries.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗
PubMed1989

[Portal vein infusion therapy of the prevention of liver metastasis from colorectal carcinomas].

For patients who underwent curative resections for primary colorectal carcinomas, locally recurrent tumors and metastatic liver tumors, we applied portal vein infusion therapy to prevent further metastases to the liver. Following radical resection of the tumor, dissecting the umbilical vein from the falciform ligament made it possible to recanalize and insert a 18 G catheter into the portal vein. Intraportal chemotherapy (5-FU 750 mg/day) was carried out for the first 7 postoperative days. There were 17 patients who received this therapy, 10 with curative resection for the primary cancers, 1 with curative resection for the locally recurrent tumor and 7 with the curative resection for the metastatic liver tumors. The follow-up period is rather short (17 months) but no patients have had the liver metastases. So we suggest that this adjuvant liver infusion may reduce the liver metastases without any mortality or morbidity.

Adult↗
PubMed1989

Histologic features of gastric cancer in relation to patterns of spread.

The modes for growth and spread of gastric cancer were investigated in a surgical series of 115 cases--88 of early disease, and 27 involving the muscular layer. In addition, 93 autopsy cases with advanced disease were examined in order to analyze metastatic spread. In cancers of differentiated type in the mucosal layer, changes in histologic features towards the undifferentiated type were observed in the deeper layers, but no histologic transformation was seen in cancers of undifferentiated type. At autopsy distant metastases were common in cases with primary tumor of differentiated type, whereas peritoneal dissemination predominated when the primary lesion was undifferentiated. From the clinical standpoint, follow-up and recommendations to the patient should focus mainly on risk of peritoneal dissemination when adenocarcinoma of the stomach is of undifferentiated type, whereas metastases to distant organs should be taken into consideration if the malignancy is histologically differentiated.

Autopsy↗
PubMed1988

A model for regulation of mammalian ribosomal DNA transcription. Co-ordination of initiation and termination.

Based on recent experimental data about transcription initiation and termination, a model for regulation of mammalian ribosomal DNA transcription is developed using a simple kinetic scheme. In this model, the existence of the transition pathway from the terminator to the promoter increases the rate of ribosomal RNA precursor synthesis. In addition to this 'non-transcribed spacer' traverse of RNA polymerase I, the co-ordination of initiation and termination allows a rapid on/off switch transition from the minimum to the maximum rate of ribosomal RNA precursor synthesis. Furthermore, taking account of the participation of two factors in the termination event, we propose a plausible molecular mechanism for the co-ordination of initiation and termination. This co-ordination is emphasized by repetition of the terminator unit.

Animals↗
PubMed1988

Postoperative acute cholecystitis: a collective review of 494 cases in Japan.

The clinical course and management of 494 patients with postoperative acute cholecystitis, encountered at 122 hospitals in Japan during the last decade, were reviewed. The incidence of the disease from the total operations was 0.06 per cent, and 445 patients (90 per cent) were acalculous. The mean age of the patients was 60 years, and the ratio of male to female was 2.8:1. Total gastrectomy, subtotal gastrectomy, and esophagectomy were the most common operations precipitating postoperative acute cholecystitis. Vagotomy, dissection of the upper abdominal lymph nodes, and prolonged fasting were prevalent among the risk factors. Clinical diagnosis was confirmed in most patients by ultrasonography. Among the various treatments, cholecystectomy brought the lowest mortality rate; the overall mortality rate being 23 per cent. When this disease is suspected, ultrasonography should be performed repeatedly and percutaneous transhepatic gallbladder drainage or cholecystectomy are recommended as being the treatments of choice.

Acute Disease↗
PubMed1988

Acute mesenteric ischemia.

Acute mesenteric ischemia is becoming an increasing cause of death in old patients with generalized atherosclerosis. Pathogenetically, this condition presents as poor splanchnic perfusion, with or without occlusion of the major visceral vessels. Because the patient manifests such nondescript abdominal pain and the physical examination reveals few abdominal signs, it is therefore extremely difficult to make an accurate diagnosis in the early stage of the disease. Furthermore, laboratory studies and X-ray examinations are usually noncontributory. It is therefore necessary to keep this lesion in mind, whenever examining the old patient with severe unexplained abdominal pain. Selective arteriography is essential for differentiating occlusive ischemia from non-occlusive, however, the recent advances in medical imaging and minute flowmetry make it possible to detect intestinal lesions and the state of visceral perfusion, transcutaneously, in the early stage of the disease. Emergency revascularization is mandatory for an occlusive lesion, but it is not indicated in the early stage of non-occlusive disease, and requires support of cardiac failure, hypovolemia, septic shock and lowered splanchnic perfusion.

Acute Disease↗
PubMed1988

Synthesis and hypolipidemic activity of 2-substituted isobutyric acid derivatives.

A series of 2-substituted isobutyric acid derivatives have been synthesized and evaluated as hypolipidemic agents. Compounds 11 and 20 were found to decrease the level of plasma total cholesterol in experimental hyperlipidemic rats to a greater extent than clofibrate (CF) and to increase the level of plasma high-density lipoprotein cholesterol to the same extent as gemfibrozil (GF). Increase in liver weight caused by these compounds were less than those with CF and GF.

Animals↗
PubMed1988

In vitro sequence-specific cleavage in transcribed spacer of mouse precursor ribosomal RNA.

When we compared the sequences near four terminal sites of transcripts including two endoribonucleolytic cleavage sites in external transcribed spacer 1 upstream of the 5' end of the mouse 18S rRNA (Mishima, Y., Mitsuma, T., & Ogata, K. (1985) EMBO J. 4, 3879-3886), a seven-nucleotide consensus sequence, GGPyUUGPy (Py is C or U), was obtained. The results of both in vitro pulse-chase experiments and S1 nuclease mappings using the mouse rDNA fragment of the transcription initiation region indicated that ribonucleolytic cleavages take place in the sequence matching the consensus sequence at more than five nucleotides out of the seven positions. Furthermore, effective ribonucleolytic cleavages in vitro were observed in a sequence, GGCUUGU, in the internal transcribed spacer 2 located between 5.8S and 28S rRNA. These results demonstrate that the ribonucleolytic cleavages occur preferentially in the sequence of GGPyUUGPy in the transcribed spacer regions of the mouse pre-rRNA. From this information, we infer the existence of processing steps for the pre-rRNA maturation involving the sequence-specific ribonucleolytic cleavages.

Animals↗
PubMed1988

Identification of a protein factor and the nucleotide sequence required for processing of mouse precursor rRNA.

We have studied the protein components and nucleotide sequence involved in the endonucleolytic cleavage at 105 bp upstream of the 5' end of mouse 18S rRNA. By fractionating the mouse S100 extract into four fractions by phosphocellulose chromatography, we separated and characterized the processing factor which participated in in vitro coupled and uncoupled transcription-processing systems. Processing activity was recovered in the flow-through fraction (fraction A), while the transcription initiation was supported by the combination of fractions C and D. This endonucleolytic cleavage activity was heat-labile and resistant to micrococcal nuclease. By constructing deletion fragments, we found that the sequence between 219 bp upstream and 26 bp downstream of the processing site was required for the processing. This sequence does not include the 18S rRNA coding region and can form a stem-loop secondary structure.

Animals↗
PubMed1988

Melanin monomers within coated vesicles and premelanosomes in melanin synthesizing cells.

We have found substantial amounts (6.6-143 and 0.5-13 micrograms/mg. protein, respectively) of 5,6-dihydroxyindole (5,6-DHI) and 5,6-dihydroxyindole-2-carboxylic acid (5,6-DHI2C), which are key intermediate monomers for the formation of the eumelanin polymer, within coated vesicle fraction of pigment cells. In addition, the amounts of these eumelanin monomers have been found to decrease along with the process of eumelanin polymer formation from coated vesicles to premelanosomes and finally to melanosomes among melanogenic subcellular compartments. Our present findings seem to indicate that coated vesicles transfer not only highly glycosylated T1-tyrosinase but also eumelanin monomers into premelanosomes.

Animals↗
PubMed1988

Induction of melanogenesis suppression: cellular pharmacology and mode of differential action.

Recent elucidation of regulatory mechanisms of eu- and pheomelanogenesis has led us towards an exciting new era of melanogenesis control. I will chiefly address our progress on inhibitory control of melanogenesis from the macromolecular level to human skin colour. In the past, the exploration and search for skin depigmenting agents has been focussed on and initiated from substances which can suppress isolated tyrosinase in vitro. Now, as I have classified below, many new melanogenic inhibitors have been discovered which, in spite of their non-suppressive effect on isolated naked tyrosinase, suppress melanin formation in the living pigment cell in vitro as well as in the natural world. I will also discuss a recently found unique disorder: unilateral suppression of mixed melanogenesis.

Animals↗
PubMed1988

Comparative analysis of oncogene expression and chromosome abnormalities between metastatic and nonmetastatic B16 melanoma clones.

We have established nonmetastatic mouse B16 melanoma clone, C1-2, and metastatic variant, C4-1, by subcloning the 30th passage of nonmetastatic W1-4 cells. We have investigated oncogene expression and chromosomal abnormalities to see whether there is some correlation with tumor progression and phenotypic diversification in melanoma cells. Not only metastatic C4-1 but also nonmetastatic C1-2 showed similarly high expression of c-Ha-ras and c-myc oncogenes by Northern blotting method. The chromosome numbers of both clones were distributed mainly within the range of 48-52. C1-2 had about 20 biarmed chromosomes and C4-1 had 13 or 14, which made real ploidy of C1-2 and C4-1, hypotetraploidy and triploidy, respectively. 21 marker chromosomes were commonly observed, while 9 marker chromosomes peculiar to C1-2 and 4 peculiar to C4-1 were constantly recognized. In partial accordance with a previous report, chromosomes 4, 5, 6, 8, 10, 13, 18, 19, and X were additionally observed in nonmetastatic C1-2 cells, compared with metastatic C4-1 cells. Furthermore, in our study, the increase of chromosomes 1, 15, and 16 was found to be greater in metastatic C4-1.

Animals↗
PubMed1988

Heterogeneity of primary malignant melanomas in oral mucosa: an analysis of 43 cases in Japan.

In contrast to Caucasians, Japanese people have a relatively high incidence of malignant melanoma in the oral cavity and volar-subungual skin. The classification of oral melanoma has not been established. We report 7 new cases of oral melanoma, with a review of 36 cases, published in Japan, between 1970 and 1984. Most of the cases reviewed have radial growth phases, and their gross and microscopic features seem to correspond to those of acral lentiginous melanoma of the skin. However, 1 of our cases and 3 previously reported cases of oral nodular melanoma suggest the presence of melanoma heterogeneity in the oral cavity.

Adult↗