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Biomedical subjects

Y Yuasa

Publications and source records attributed to Y Yuasa.

At least 55 records · Page 3Linked to original sources
PubMed1988

Intraarterial digital subtraction angiography with carbon dioxide: superior detectability of arteriovenous shunting.

Intraarterial digital subtraction angiography (IADSA) with carbon dioxide (CO2) was performed on 41 patients with liver or renal diseases. CO2 produced no hypersensitivity reactions, and the pain or feeling of warmth was relatively mild compared with iodinated contrast media. Although the image quality of the arterial or capillary phase was inferior to that with iodinated contrast media, the detectability of arteriovenous shunting was excellent. IADSA with CO2 may become an effective method for detecting arteriovenous shunting which cannot be demonstrated with conventional angiography or DSA with iodinated contrast medium.

Adult↗
PubMed1988

Multi-step neoplastic transformation of normal human fibroblasts by Co-60 gamma rays and Ha-ras oncogenes.

As reported previously (Namba et al., 1985; Namba, 1985), normal human fibroblasts were transformed into immortal cells with abnormal karyotypes by Co-60 gamma-ray irradiation. These immortally transformed cells (KMST-6) showed no clonability in soft agar and were not tumorigenic. However, by treatment with Ha-ras oncogenes derived from a human lung carcinoma or Harvey murine sarcoma virus, the KMST-6 cells acquired elevated clonability in soft agar and transplantability in nude mice. All the tumors produced grew progressively without showing regression and killed the mice. The tumors were also serially transplantable into other mice. The Ha-ras oncogene alone did not convert normal human fibroblasts into either immortal or tumorigenic cells. Our current data suggest that gamma rays worked as an initiator of carcinogenesis in normal human cells, giving rise to chromosome aberrations and immortality, and the Ha-ras oncogene played a role in the progression of the immortally transformed cell population to a neoplastic one showing enhanced colony formation in soft agar and tumorigenicity in nude mice.

Cell Line↗
PubMed1988

[Long-term maintenance of human gall-bladder epithelia as xenografts following explant organ culture].

The purpose of present study is to establish a method that should enable us to keep a human gall-bladder epithelial tissue alive for a period long enough to observe morphological change after an exposure to a certain carcinogenic agents. Human gall-bladder epithelia obtained from surgically resected specimen were kept as an explant organ culture in vitro for the first 2 weeks. They were, then, xenotransplanted to the subcutaneous (S.C.) space of the athymic nude mice. The gall-bladder tissues obtained from 7 cases of cholecystolithiasis and 1 case of cholecysto-choledocholithiasis were used as materials in the present study. And the longest survivor among them in the nude mice was extensively studied in the present paper. After an interval of 4 to 27 weeks, the xenografts were recovered from the recipient mice and studied by light microscopy and histochemistry. The morphological changes of the explant epithelia during the organ culture were also studied. Parts of the explants were implanted in 6 nude mice. Each of the mice received 3 pieces of explants on the s.c. space in both of their flanks. All xenografts showed subcutaneous cyst formation. The cyst obtained 4 weeks after the implantation was consisted of a monolayer of cuboidal epithelial cells and those recovered from the recipient mice 24 and 27 weeks after the implantation were consisted of well growing columnar and cuboidal epithelial cells. In addition, sinus-like structures were observed beneath the cystic epithelia. The viability of the cells was excellent.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Distribution of basal lysosomes in exocrine acinar cells.

We examined the distribution of trimetaphosphatase (TMPase)-positive basal lysosomes in pancreas, parotid, submandibular, sublingual, and exorbital lacrimal glands from rats, rabbits, and guinea pigs. The location of the basal lysosomes was compared to that of the acid phosphatase (AcPase)-positive lysosomes. In all of the tissues examined from rat and rabbit, AcPase activity was localized primarily to the Golgi region. Reaction product was localized in GERL, immature secretory granules, and lysosomes lying adjacent to the Golgi apparatus. TMPase activity was found in basal lysosomes and in occasional elongated lysosomes adjacent to the Golgi apparatus. In guinea pig, the distribution of TMPase activity was identical to that seen in the other two species, but a significant number of lysosomes in the basal region of the cells also contained AcPase activity. These results confirm and extend our previous finding (J Histochem Cytochem 31:1209, 1983) that exocrine acinar cells possess two distinct populations of lysosomes. The lysosomes in the Golgi region contain both AcPase and TMPase activity, whereas those in the basal portion of the cells are reactive predominantly for TMPase. The functional significance of the two populations of lysosomes is not understood at present.

Acid Anhydride Hydrolases↗
PubMed1987

Transforming genes in human hepatomas detected by a tumorigenicity assay.

Two transforming sequences in human hepatomas were detected by means of a tumorigenicity assay in nude mice using transfected NIH3T3 cells. Through hybridization with known oncogene probes, the transforming gene in one hepatoma was found to be the human hst gene. The transforming sequence in the other hepatoma showed no sequence homology with any of the oncogenes examined.

Animals↗
PubMed1986

Effects of interventricular shunt on indices of left ventricular function.

The accuracies of indices of left ventricle function were examined in an open-chest model in dogs with and without a ventricular septal defect, in which the ventricular shunt was opened and reclosed by a specially designed flowmeter probe with a cap. The systolic time interval, the maximal rate of pressure development in the left ventricle (+LV dP/dt), +LV dP/dt corrected for the isometric pressure (+LV dP/dt/Pd), and the time to +LV dP/dt (t-dP/dt) were determined by recording the aortic flow, ventricular shunt flow, aortic pressure, pulmonary arterial pressure, and left ventricular pressure. The isometric contraction time, the preejectional period, and the ejection time shortened with decrease of the mean aortic pressure and aortic flow, and the mean pulmonary arterial pressure increased after opening the ventricular shunt. When the pulse was varied by atrial pacing, the systolic time interval was affected in dogs both with and without a ventricular septal defect, but "isometric contraction time" was not affected in animals with a ventricular septal defect. Dopamine and methoxamine were used to evaluate the effects of the inotropic state and afterload on these indices. The extents of the changes in the systolic time interval and +LV dP/dt were different in animals with and without a ventricular septal defect, but the changes in preejectional period/ejection time, +LV dP/dt/Pd and t-dP/dt were similar in the two conditions. These results suggest that the systolic time interval and the indices of left ventricular pressure are useful in assessment of cardiac function only in certain conditions.

Animals↗
PubMed1986

Change in pulmonary and systemic circulation in acute ventricular septal defect.

The correlation between left to right ventricular (L-R) shunt flow and other hemodynamic changes was studied in 16 dogs with an acute ventricular septal defect (VSD) and normal pulmonary vascular bed. The interventricular shunt flow was measured directly with a specially designed electromagnetic flowmeter probe, where the area of the VSD was constant. The sudden presentation of VSD increased pulmonary arterial pressure, pulmonary flow and left ventricular end-diastolic pressure. L-R shunt flow was not changed significantly by atrial pacing except when the rate was increased to over 200/min. Dogs with a VSD were treated with isoproterenol and dextran to vary the shunt flow and hemodynamic parameters. L-R shunt flow was decreased by isoproterenol and increased by dextran loading. The percentage changes of L-R shunt flow from pre-drug values correlated well with the change in left ventricular end-diastolic pressure (r = 0.75) and the ratio of pulmonary to systemic vascular resistance (r = -0.73). Change in total pulmonary vascular resistance had a greater effect on L-R shunt flow than did a change in systemic vascular resistance, whereas a change in aortic flow had less effect (r = 0.35) on L-R shunt flow than did a change in preload and afterload. The time to peak LV dP/dt, as an index of cardiac contractility, and heart rate were not correlated with the relative change in L-R shunt flow. These results indicate that L-R shunt flow induced by the sudden presentation of a VSD varied with changes in the pulmonary and systemic circulation.

Animals↗
PubMed1986

Activated N-ras in a human rectal carcinoma cell line associated with clonal homozygosity in myb locus-restriction fragment polymorphism.

An N-ras transforming gene was detected in human rectal carcinoma-derived cells (7060) and molecularly cloned. The genetic lesion responsible for the transforming activity of the 7060 oncogene was localized to a single nucleotide transition from A to T in codon 61 of the predicted protein. This lesion in the second exon results in substitution of histidine for glutamine at this position. We also found an EcoRI restriction fragment length polymorphism, consisting of two alleles, of the human c-myb gene. The 7060-transformed epithelial cells showed the homozygous phenotype, while normal fibroblasts of the same patient showed the heterozygous phenotype. This suggests a relationship between the phenotypic change in the c-myb locus and the induction of the 7060 tumor.

Carcinoma↗
PubMed1986

Colon carcinoma K-ras 2 oncogene of a familial polyposis coli patient.

The DNA of a colon carcinoma-derived cell line (KMS-4) and that of skin fibroblasts from a familial polyposis coli patient were transfected into NIH3T3 cells in order to detect oncogenes associated with the disease. No transformation was observed with the normal skin fibroblast DNA, while the KMS-4 cell DNA was able to transform NIH3T3 cells. Through hybridization with known oncogene probes, the KMS-4 transforming gene was found to be a human activated c-K-ras 2 oncogene. Sequence analysis of the molecularly cloned KMS-4 c-K-ras 2 oncogene showed a single nucleotide transition from G to T at the 12th codon. This results in substitution of cysteine for glycine at this position. On using labeled synthetic oligonucleotides to detect the mutation in codon 12, we found the G to T transition in colon carcinoma cells. This suggests that activation of the c-K-ras 2 oncogene could be associated with colon carcinoma induction.

Adenomatous Polyposis Coli↗
PubMed1986

[Clinical studies on cefixime in pediatrics].

A clinical study of cefixime (CFIX), a new oral cephalosporin, was carried out to evaluate its therapeutic effectiveness on bacterial infections in children. CFIX was orally administered to 13 patients including 6 with upper respiratory tract infection (RTI), 3 with pneumonia, and 1 each with bronchitis, otitis media, skin abscess, and urinary tract infection (UTI). The daily dosage per kg bodyweight ranged from 5.1 to 17.4 mg (average: 8.7 mg), and was given in 2 or 3 divided doses per day for 3 to 10 days (average: 5.8 days). The clinical response was excellent in 4 (30.8%), good in 7 (53.8%) and poor in 2 (15.4%), with an overall efficacy rate of 84.6%. Bacteriological efficacy was good, and 6 of the 8 identified causative organisms were eradicated. Side effects were observed in 3 children, i.e., loose stool in 1 and transient elevations of GOT and GPT in 2. The above results suggest that CFIX is a useful new oral cephalosporin for the treatment of bacterial infections in children.

Bacteria↗