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Biomedical subjects

N Kawashima

Publications and source records attributed to N Kawashima.

At least 109 records · Page 6Linked to original sources
PubMed1978

Late effects of fetal mice x-irradiated at middle or late intrauterine stage.

Mice of F1 hybrids of (C57BL/6xWHT) strains were exposed in utero to 200 R of X-rays at 12 or 16 approximately 18 days post coitum. Mice of both sexes were allowed to liver through their life span, and the induction of tumors, growth retardation, and induction of degenerative diseases were examined. A significant enhancement of lung, pituitary gland, and ovary tumorigenesis was observed in mice irradiated at the late intrauterine stage. Also, incidence of liver and skin tumors was increased slightly in this group, whereas thymic lymphomas were not induced. Persistent growth retardation, several congenital malformation, and amyloid degeneration were found in mice irradiated at the middle intrauterine stage. However, no increases incidence of tumors was seen in this group. Moreover, incidnece of lymphoreticular tissue tumors, lung tumors, and leiomyosarcomas of uterus was significantly decreased by irradiation at the middle intrauterine stage from the unirradiated control and the late intrauterine irradiated group.

Adenocarcinoma↗
PubMed1976

Origin of sequence heterogeneity of the small subunit of fraction 1 protein from Nicotiana tabacum.

The partial amino acid sequences of the small subunit of Fraction 1 protein from N. sylvestris, N. tomentosiformis and N. tabacum were determined. The sequence of N. sylvestris is NH2. Gln-Val-Trp-Pro-Pro-Ile-Asn-----Tyr COOH. In the sequence up to the 7th amino acid and C-terminus, differences were only found at the 6th position in the three species, where N. sylvestris and N. tomentosiformis show Ile and Tyr, respectively. N. tabacum show both Ile and Tyr in almost equal amount at this position. These results confirmed a previous hypothesis that N. tabacum had been evolved through the hybridization of N. sylvestris and N. tomentosiformis.

Amino Acid Sequence↗
PubMed1976

Origin of Nicotiana tabacum detected by primary structure of fraction I protein.

Nicotiana tabacum is believed to have arisen after hybridization of Nicotiana sylvestris with a species in the Tomentosae section of the genus Nicotiana. Recent biochemical experiments have confirmed the conclusions from previous cytogenetic studies that N. sylvestris was the maternal parent and have indicated that Nicotiana tomentosiformis was the paternal parent. However, these studies did not take into account the possibility that a new species of Nicotiana, called K-12, discovered in South America in 1968, could also have been one of the parents. Fraction I proteins were purified from N. tabacum and its putative progenitors, and separated into large and small subunits. Chymotryptic peptides of each subunit were analyzed by ion exchange column chromatography with a gradient elution system. Among 38 resolved peaks of the large subunits, 2 peaks were found to be different among the putative species. Since only N. sylvestris showed an identical chromatogram with N. tabacum, N. sylvestris was concluded to be the maternal progenitor, as the genetic information for the large subunit of Fraction I protein was known to be inherited by the cytoplasmic mode. On the other hand, the small subunit of Fraction I protein is inherited by the Mendelian mode and therefore N. tabacum, an allopolyploid, could be expected to contain two types of small subunits, one derived from N. sylvestris and the other from a paternal progenitor. N. sylvestris lacks two of the 25 chymotryptic peptides of the small subunit of N. tabacum. Among 3 putative paternal progenitors, these two peaks appeared only in N. tomentosiformis, but not in Nicotiana otophora or K-12. Thus, N. tomentosiformis was concluded to be a paternal progenitor of N. tabacum. The conclusion was verified by comparing chymotryptic peptides of small subunits from three amphidiploids of N. sylvestris crossed with N. tomentosiformis, N. sylvestris crossed with N. otophora snd N. sylvestris crossed with K-12. The analytical results showed that only the progeny of N. sylvestris crossed with N. tomentosiformis contained the same small subunits as N. tabacium.

Chymotrypsin↗
PubMed1976

Prediction of radiosensitivity of individual mice by multidimensional analysis.

Ten physiological indices on each mouse were measured before an exposure to ionizing radiation. The exposure of mice to 700R of X-rays induced 45% mortality within 30 days. A prediction of death or life of each mouse was done by a multidimensional quantification. The highest success rate of prediction was obtained by using all ten indices and it resulted in 74.1%. Accordingly, it was possible to predict death of individual mice exposed to a dose around LD50 (30) with a high rate of success. When one selected five indices out of the ten indices by some criterion, the success rate of prediction decreased to 67.1%.

Animals↗