Suppression of erythropoiesis by actinomycin D. 3. The effect of actinomycin D on the hemoglobin level of bone marrow erythrocytes and erythroblasts

For the purpose of revealing whether or not hemoglobin synthesis is inhibited by the AMD, the author estimated the hemoglobin level of AMD treated anilmals by microspectrophotometer, and found that the hemoglobin levels of all the developmental stages of erythroid cells were not inhibited by the AMD. The data indicated that about one half of mRNA for hemoglobin is synthesized in the early stage of specialization with the supplementary synthesis at the later stages and all these mRNA is stable and insensitive to AMD.</p

Suppression of erythropoiesis by actinomycin D. II. The change in RNA metabolism by actinomycin D administration

For the purpose of revealing whether AMD inhibits the RNA synthesis of erythroblasts in an effective dose in vivo to eradicate erythroid cells in rabbit bone marrow, the author observed the RNA synthesis by H3-uridine incorporation in vitro and RNA level on the cells from the anemic animals taken at a certain period after a single injection of AMD in a small dose of 50 and 100&#956;g/kg body weight. The data revealed that by such a small dose of injection of AMD the RNA synthesis of erythroid precursors, early basophilic and proerythroblast stages, was successfully suppressed without any suppressing effect on the RNA synthesis of erythroblasts in the later stages of specialization, indicating that there are at least two kinds of RNA synthesis: one seen mainly in the earlier stages of specialization and the other one seen mainly in the later stages, and they can be distinguished from each other by the AMD sensitivity.</p

Suppression of erythropoiesis by actinomycin D. I. Evolutional change of hemopoiesis by actinomycin D

For the purpose of revealing whether the sensitivity of the erythropoiesis to actinomycin D (AMD) differs among different animal species, and to see the acting site of AMD on erythroid cell specialization stage, the author observed the hourly change of the blood cell counts and bone marrow cells after AMD administration to mice, rats and rabbits, and obtained the following results: 1. The data indicated that the erythropoiesis of ra bbit is sensitive to AMD, as much as that of mice, while the rat is resistant to AMD, and its erythropoiesis is not affected by the similar dose of AMD as in the case of mouse and rabbit. 2. The morphologic observations on the eradication process of erythroblasts in the bone marrow of mice and rabbits indicates that AMD acts as to inhibit the transformation of the stem cell to the proerythroblast but not on the erythroblast in the course of specialization. The time required for the eradication coincided with the time of the proerythroblast to the mature red cell. 3. Discussion has been made on the possibility of the common stem cell to erythroid and granulocytic cells in relation to the lymphoid cells in bone marrow and their blast form.</p

Serum bleomycin-detectable iron in patients with thalassemia major with normal range of serum iron.

&#34;Free&#34; iron, a potentially radical-generating low mass iron, and not found in normal human blood, was increased in the serum of blood-transfused thalassemia major patients seen in the Yangon General Hospital, Yangon, Myanmar (Burma). The low mass iron was detected by the bleomycin assay. Fifty-one blood samples were analyzed (from 28 males and 23 females). High &#34;free&#34; iron was detected in 47 sera samples from thalassemia patients. Serum ferritin, which reflects the body store iron, was higher than the normal range (10-200 ng/ml) in 49 patients. On the other hand, serum iron of 39 sera samples fell within the normal range (50-150 micrograms/dl). Four were less than 50 micrograms/dl and eight were more than 150 micrograms/dl. Almost all the patients' sera of normal or higher serum iron level contained &#34;free&#34; iron. Thus, almost all the sera from thalassemic patients from Myanmar contain bleomycin-detectable iron, even when serum iron is within the normal range. In developing countries where undernutrition is prevalent (serum albumin in these patients was 3.6 +/- 0.4 g/dl, P &#60; 0.0001 vs. control value of 4.0 - 4.8 g/dl), normal serum iron does not preclude the presence of free iron in the serum.</p

Effects of phlebotomy on the growth of ferric nitrilotriacetate-induced renal cell carcinoma.

The ferric nitrilotriacetate-induced carcinogenesis model is unique in that reactive oxygen species-free radicals are involved in the carcinogenic process. But the effects of iron-withdrawal in the progression of renal cell carcinoma are not well understood. We performed repeated phlebotomies on animals that had been administered ferric nitrilotriacetate in the initiation stage of renal cell carcinoma (phlebotomy group), and compared the development of renal tumors with those not receiving repeated phlebotomies (non-phlebotomy group). Ferric nitrilotriacetate-treated male Wistar rats were randomly divided into 2 groups: a phlebotomy group (21 rats) and a non-phlebotomy group (17 rats). Ten age-adjusted normal rats were also observed as a normal group. Hematocrit was maintained under 25% in the phlebotomy group. Hematocrit levels in the normal group and in the non-phlebotomy group were not significantly different. As a result, the incidence of renal cell carcinoma was not significantly different between phlebotomy and non-phlebotomy animals. However, the total weight of the renal cell carcinoma was significantly heavier in the animals from non-phlebotomy group than in those from the phlebotomy group (23.64 g +/- 18.54 vs. 54.40 g +/- 42.40, P &#60; 0.05). The present study demonstrated that phlebotomy after the administration of ferric nitrilotriacetate did not reduce the incidence of renal cell carcinoma. In addition, we showed that iron withdrawal at the promotion stage of carcinogenesis will retard tumor growth.</p

Specific antigen of tumor cell transformed by DNA extracted from SV-40 virus

In the immunofluorescent study it has been revealed that rabbit sera immunized with transformed cells induced by SV-40 DNA, produce circulating antibody capable of re:lcting with intranuclear antigens synthesized by SV-40 complyte virus transforming process, In addition, the result confirmed that SV-40 DNA replicates DNA-containing viruses in the host cell and that also the genome coding for the synthesis of SV-40 tumor antigen is resposible for viral DNA.</p

Monochloramine inhibits ultraviolet B-induced p53 activation and DNA repair response in human fibroblasts

AbstractMonochloramine (NH2Cl) is one of the inflammation-derived oxidants, and has various effects on cell cycle, apoptosis and signal transduction. We studied the effects of NH2Cl on DNA repair response induced by ultraviolet B (UVB) irradiation in normal human diploid fibroblasts, TIG-1. TIG-1 irradiated with 20 mJ/cm2 UVB showed marked increase in thymine dimer, which decreased by about 50% after 24 h. This decrease in thymine dimer was significantly attenuated (P<0.05) by the pretreatment of NH2Cl (200 μM), which indicated DNA repair inhibition. UVB induced p53 phosphorylation at Ser15, Ser20 and Ser37, and p53 accumulation, and NH2Cl also inhibited these changes. Consequently, UVB-induced increase in the downstream effectors of p53, namely p21Cip1 and Gadd45a, were almost completely inhibited by NH2Cl. Immunoprecipitation study indicated that the association of p53 and MDM2, an E3 ubiquitin ligase for p53, did not change substantially by NH2Cl and/or UVB. The phosphorylation of p53 (Ser15 and Ser37) by UVB is catalyzed by ATR (ataxia telangiectasia mutated and Rad3 related kinase), which works as DNA damage sensor, and ATR also phosphorylates checkpoint kinase 1(Chk1) at Ser345. NH2Cl also inhibited the phosphorylation of Chk1 (Ser345). As UVB-induced DNA damage is repaired by nucleotide excision repair (NER) in human cells, these findings indicated that NH2Cl inhibited NER through the inhibition of p53 phosphorylation and accumulation, and NH2Cl probably impaired DNA damage recognition and/or ATR activation. NH2Cl may facilitate carcinogenesis through the inhibition of NER that repairs DNA damages from various carcinogens

\u3cem\u3eBotryoccocus Braunii\u3c/em\u3e Triterpene Synthase Proteins and Nucleic Acid Molecules, and Methods for Their Use

This application relates to the functional identification and characterization of a nucleic acid molecule encoding a triterpene synthase, in particular botryococcene synthase. Also described are host cells comprising the nucleic acid molecules of this invention, proteins encoded by the nucleic acid molecules and methods for using the nucleic acid molecules, transformed hosts and encoded proteins to produce high levels of triterpene hydrocarbons