The cell kinetic, tumorigenic and carcinogenic effects of the short acting, alkylating carcinogen N-methyl-N-nitrosourea (MNU) on hairless mouse epidermis were investigated. The epidermal mitotic rate, the mitotic index, and the number of basal and suprabasal cells were scored in histological sections. Incorporation of [3H]thymidine and flow cytometric analysis of cellular DNA and protein content were performed on isolated basal cells at intervals for up to 10 days after a single application of either 1 or 10 mg MNU. The ensuing tumor rates and yields were observed for up to 48 weeks after 1 mg MNU and 30 weeks after 10 mg MNU. Generally, MNU induced an initial delay in epidermal cell cycle progression with an accumulation of cells in the S and G2 phases. Some days after treatment the delayed cells were released and entered mitosis. One milligram MNU caused a moderate delay of cells in S and G2, lasting for 2-3 days, and this was followed by a release leading to an increased number of suprabasal cells on day 7. The highest dose of MNU caused a more pronounced delay in transit through S and G2 and seemed to be followed by rapid regenerative proliferation. The subsequent tumor crop after 10 mg was significantly higher than that seen after the lowest dose. The present cell kinetic results are consistent with previous data from the study of other carcinogens, all showing a carcinogen-induced initial reduction in DNA synthesis after appropriate doses. A delay in transit through G2 phase was found as well, indicating that a general delay in cell cycle progression may follow the application of most (or all) carcinogens.
SUMMARY A fatal case of generalized BCG infection following vaccination is reported. The patient, a girl BCG‐vaccinated at the age of six weeks, developed septic fever and leucocytosis at 5 1/2 months of age and died at 7 months of age in a poor condition with extensive edemas, icterus and severe attacks of general convulsions. Autopsy revealed disseminated tuberculosis. The histological picture showed little tendency to tuberculoid structure, marked caseous necrosis and myriads of acid‐fast bacilli in the affected areas. By bacteriological examination the acid‐fast bacilli were indistinguishable from BCG. Increased virulence or other changes in the BCG vaccine which might explain the fatal complication has not been found. Two of the patient's three siblings had previously shown definite signs of reduced resistance to infection, and both died at an early age from infections. Adding this to the patient's case history, one feels justified in concluding that a familial resistance impairment to infection is present. The cause of this deficiency is discussed. There are at present five known cases of fatal BCG infection following vaccination in Scandinavia, and the number of persons vaccinated is estimated to be between 6 and 7 millions. The probable incidence of fatal complications can thus be put at less than one case per million vaccinated. As the protective effect of BCG vaccination is beyond doubt and the serious complications extremely rare, there seems to be no ground at present for objecting to continued BCG vaccination.
Study question How does glycolytic pathway-related protein A1 (GPRPA1) relate to the pathogenesis of recurrent pregnancy loss (RPL)? Summary answer GPRPA1 was found as a substrate of ITI-H4 to modulate the inflammatory response and was down-expressed in the sera of RPL patients. What is known already Thus far, the pathogenesis of RPL was not fully understood. In a previous study, the short isoform ITI-H4 cleaved by kallikrein B1 was detected in the sera of RPL patients and would be an important inflammatory factor for RPL by increasing pro-inflammatory cytokines. GPRPA1, a new binding partner of ITI-H4, was known to relate with pre-eclampsia and human decidualization by regulating angiogenesis and glycolysis. Also, GPRPA1 affects placental cell motility and cancer cell proliferation. Study design, size, duration Through immunoprecipitation (IP) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF/MS) analyses, we found new binding partners of ITI-H4. Of these, GPRPA1 was selected, and direct binding between GPRPA1 and ITI-H4 was confirmed by IP and GST pull-down assay. Differential expression of GPRPA1 in sera and cellular functions of GPRPA1 in the placental cell line were investigated by molecular and cellular analyses. Participants/materials, setting, methods The Flag-tagged full-length ITI-H4 and the short isoform ITI-H4 were transfected into HEK293T cells and IP has proceeded with the Flag antibody. Spots showing differential expression were analyzed by MALDI-TOF/MS analysis and peptide sequence alignment was performed. The binding between GPRPA1 and ITI-H4 was confirmed using IP and GST pull-down assay. The effects of GPRPA1 on cellular functions in the placental cell were investigated by CCK–8 assay, invasion assay, and colony-forming assay. Main results and the role of chance Through IP, MALDI-TOF/MS analysis, and peptide sequence alignment, we found new substrates of ITI-H4 related to glycolysis, T cell activation, and production of thyroid hormones. Of these, we selected GPRPA1 which is secreted in the serum to utilize a serum biomarker of RPL. GPRPA1 directly binds to the full-length ITI-H4 and also binds to the short isoform ITI-H4 shown by IP and GST pull-down assay. Besides, GPRPA1 as a protein kinase increases serine phosphorylation of ITI-H4 and inhibits the cleavage by KLKB1. GPRPA1 is expressed significantly lower in the sera of PRL patients than the control group and knockdown of GPRPA1 negatively regulates cell motility in the placental cell. Therefore, down-expressed GPRPA1 would be one of the causes of RPL and can be utilized as a serum biomarker of RPL. Limitations, reasons for caution Additional in vivo study is needed to specifically investigate the effect of GPRPA1 on the pathogenesis of RPL. Wider implications of the findings: By investigating the cellular functions of GPRPA1 in the placental cell, we found that it is an important key factor for the pathogenesis of RPL, and down-regulation of GPRPA1 can be utilized as a biomarker of RPL. Trial registration number Not applicable
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