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Biomedical subjects

S Tsuda

Publications and source records attributed to S Tsuda.

At least 253 records · Page 14Linked to original sources
PubMed1984

[Secondary leukemia following chemotherapy of various malignancies].

Recently, there has been much concern that cancer chemotherapy may have undesirable consequences in the form of secondary malignancies. At present, secondary leukemia or therapy-linked leukemia constitutes a well delineated clinical syndrome characterized by several distinct symptoms, that was illustrated by the presentation of cases recently observed. In an attempt to understand the basis for this therapy-linked leukemia, mutagenic activity of various anticancer agents were studied by the induction of sister chromatid exchanges and risk of a certain drug as a possible candidate causing secondary leukemia was discussed from the molecular cytogenetic point of view. From both clinical and cytogenetic aspects it seemed that bifunctional alkylating agents were potentially relevant to the development of secondary leukemia.

Alkylating Agents↗
PubMed1983

Chemical modification of cytosine residues of U6 snRNA with hydrogen sulfide (nucleosides and nucleotides. Part 49 [1]).

Sulfhydrolysis of cytosine residues to 4-thiouracil residues in mouse U6 snRNA was carried out to examine the secondary structure of U6 snRNA. The cytosine residues at positions 6, 42 and 68 were modified significantly, and at positions 11, 19 (or/and 25), 61 and 66 in moderate extent. Based on the result, the plausible secondary structure of U6 snRNA is discussed.

Animals↗
PubMed1983

Chemical modification of guanine residues of mouse 5 S ribosomal RNA with kethoxal. (Nucleosides and nucleotides 46).

Chemical modification of mouse 5 S rRNA with kethoxal was carried out to examine the secondary structure. The guanine residues located at positions 37, 41, 56, 66, 75 and 89 were modified. The relative rates of reaction are in the order G37, G56, G89, G66, G41, G75 at 28 degrees C and G37, G41, G56, G89, G75, G66 at 35 degrees C. These results support a secondary structure model containing 5 helices and 5 loops and indicate that the region around position 37 is the most exposed in higher-order structure.

Aldehydes↗
PubMed1983

Chemical modification of cytosine residues of mouse 5 S ribosomal RNA with hydrogen sulfide. (Nucleosides and nucleotides 43).

Cytosine residues of nucleic acids were converted to 4-thiouracil residues with hydrogen sulfide in pyridine and water to examine the secondary and tertiary structures of mouse 5 S rRNA. The cytosine residues at positions 10, 24, 34 (or 36), 39, 44 (or 46) and 63 were converted preferentially when the treatment was carried out at 28 degrees C. This result supports the model of the secondary structure of 5 S rRNA of Nishikawa, K. and Takemura, S. ((1974) FEBS Lett. 40, 106-109) consisting of five helices and five loops. As the temperature was increased to 35 degrees C, additional cytosine residues in positions 26, 52 and 78 were modified to moderate extents.

Animals↗
PubMed1983

[Primary adenosquamous carcinoma of the ileum--a case report].

A 41-year-old woman with a mass of the right lower abdominal quadrant was admitted to our hospital. Ileocecal resection was performed on December 30, 1975; and she is in good health at present. The resected specimen showed a protruded tumor with a central excavation at the terminal ileum; there was a small cyst in the submucosal layer. Histologically, most of the tumor consisted of squamous cell carcinoma. A small nest of squamous metaplasia and adenocarcinoma was observed at the cyst wall. The pathological diagnosis was adenosquamous carcinoma arising from an enterogenous cyst of the ileum.

Adenocarcinoma↗
PubMed1983

Chemical modification of adenine residues in mouse 5S rRNA with monoperphthalate: the secondary structure of 5S rRNA.

The chemical modification of adenine residues in mouse 5S rRNA with monoperphthalate was carried out to investigate the higher ordered structure of 5S rRNA. The adenine residues at positions 11, 22 (or/and 23), 49 (or/and 50), 54 (or/and 55), 77, 83, 88, 90 and 100 (or/and 101) were modified. This result further confirmed the secondary structure of 5S rRNA constituted of 5 helices and 5 loops postulated by other chemical modifications.

Animals↗
PubMed1982

Pale eosinophilic inclusions simulating ground-glass appearance of cells of hepatocellular carcinoma.

Pale eosinophilic inclusions simulating ground-glass appearance were observed in cells of hepatocellular carcinoma. They were round or elliptical in shape, and their size was about 14 micrometers in diameter. Light eosinophilia and fine granulation with homogeneous appearance were delineated from other cellular materials. They were negative for HBsAg, blood plasma proteins including alpha 1-antitrypsin, and alpha-fetoprotein by immunohistochemical stainings. Ultrastructurally, they were well-demarcated and consisted of homogeneous finely granular matrix. Histological, histochemical and ultrastructural features were different from several intracellular inclusions hitherto reported on hepatocellular carcinoma. These changes may represent a deposition of secretory proteinous materials in cells of hepatocellular carcinoma, but their chemical and antigenetical content could not be identified.

Antigens↗
PubMed1982

[Right and left ventricular systolic time intervals in patients with atrial septal defect measured by the ultrasonic Doppler method].

Noninvasive measurement of right and left ventricular systolic time intervals (STIs) was made utilizing ultrasonic Doppler method in 35 patients with secundum atrial septal defect (ASD) to evaluate their hemodynamic states. Using the Doppler signals relating to the opening and closure of the pulmonary and aortic valves, both right and left ventricular preejection periods (RPEP, LPEP) and ejection times (RVET, LVET) were measured. The same studies were carried out in 50 control healthy subjects. In patients of ASD without pulmonary hypertension (mean pulmonary arterial pressure less than 20 mmHg), RPEP did not differ significantly from that of healthy subjects, while RVET was significantly prolonged reflecting right ventricular volume overloading. In patients with pulmonary hypertension (mean pulmonary arterial pressure greater than or equal to 20 mmHg), RPEP was prolonged and RPEP/RVET was significantly higher than those in healthy subjects. These two parameters were correlated well with pulmonary arterial pressure. In both groups LVET was shorter and LPEP/LVET was larger than those of normal, suggesting low output state of the left ventricle. In 5 surgical cases, LVET was prolonged and LPEP/LVET decreased after operation, while the right ventricular STIs did not change significantly. With the pulmonary to systemic flow ratio (Qp/Qs), only RVET/LVET was correlated significantly, but with poor correlation coefficient (r = 0.47, p less than 0.01). These data may suggest that noninvasive measurement of combined right and left ventricular STIs is useful to assess the hemodynamic states of ASD, especially for evaluation of associated pulmonary hypertension.

Adolescent↗