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Biomedical subjects

H Sawada

Publications and source records attributed to H Sawada.

At least 595 records · Page 33Linked to original sources

Genome complexity and in vivo transcription in human leukemic leukocytes.

Human DNA contains 35 percent repetitive and 65 percent nonrepetitive sequences. Eight satellite DNAs have now been identified in human DNA. The highly repetitive non-satellite sequences are arranged in blocks 1,100 nucleotides long and interspersed with intermediate repetitive and nonrepetitive sequences greater than 2,500 nucleotides long. Approximately 2.5-3.9 percent of the nonrepetitive sequences are represented in total cellular RNA of normal and leukemic leukocytes.

Base Sequence↗

Unscheduled DNA synthesis in human lymphocytes treated with neocarzinostatin.

In an attempt to quantitate DNA repair induced by Neocarzinostatin, the incorporation of labeled thymidine into the human peripheral lymphocytes after exposure to the agent was studied by autoradiography. The exposure of lymphocytes to Neocarzinostatin for 60 min at the concentrations as low as 0.05 mug/ml caused a significant increase in the number of grains per cell within 2 hr of incubation with 10 muCi/ml of 3H-thymidine in the presence of 2mM of hydroxyurea. The number of grains increased with the increasing dose of the agent up to the concentration of around 2.5 mug/ml and then fell at higher concentrations. The extent of maximum incorporation induced by Neocarzinostatin was found to be almost comparable to that induced by 100 erg/mm2 of UV irradiation. Hydroxyurea or caffeine in the labeling medium showed little or no effect on the grain count, but acriflavine at 0.1 mM reduced the grain count by a factor of about 6. These results indicate that relatively high level of repair synthesis occurred in human lymphocytes after exposure to Neocarzinostatin and provide further evidence for the direct damage of cellular DNA induced by the antibiotic.

Antibiotics, Antineoplastic↗

[Spread of acute haemorrhagic conjunctivitis virus in virgin soil (Hokkaido, Japan): observation with serological surveys (author's transl)].

Acute haemorrhagic conjunctivitis (AHC), a novel disease caused with a new type of enterovirus, occurred for the first time in Sapporo City and other areas of Hokkaido in October of 1971. During first 4 months, 1,000 or more cases of AHC were reported in Sapporo and 2,300 cases in other areas. Thereafter, there are no epidemic of AHC in any areas, though there are sporadic cases up to date. To know the spread of exogenous agent, AHC virus, in Hokkaido, the neutralizing antibody was measured with sera of healthy adults resident in 12 separated districts of Hokkaido in 1973 and 1974. It was revealed that the positive reactors to AHC virus were found in 5 to 35% in all districts but one in 1974, and AHC virus was distributed in almost all the areas of Hokkaido within a period of two and half years after invasion. In addition, a sequential sero-survey to detect the spread of AHC virus has been carried out in Sapporo. A rate of neutralizing antibody positives in healthy adults did not show a clear increase on sera withdrawn one year after epidemic of AHC in comparison with those before epidemic, but show a remarkable increase on sera withdrawn later in spite of non-epidemic. An increase of antibody positive rate in non-epidemic period was also obtained from sera of healthy adults resident in districts other than Sapporo. These findings made doubt the changes in transmission on mode and/or in clinical pictures, and the viral mutation in biological character, such as temperature for propagation, may be supposed.

Adolescent↗