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Biomedical subjects

M R Banerjee

Publications and source records attributed to M R Banerjee.

At least 55 records · Page 3Linked to original sources
PubMed1976

Reduced DNA repair in mouse satellite DNA after treatment with methylmethanesulfonate, and N-methyl-N-nitrosourea.

We have measured DNA repair in mouse satellite and main band DNA as resolved by Ag+-Cs2SO4 centrifugation in response to treatment with the alkylating agents, methyl methanesulfonate, and N-methyl-N-nitrosourea. We find that there is a statistically significant lower incorporation of 3H-Tdr into the satellite DNA as compared to the main band at varying periods after treatment with the alkylating agents. This suggests a reduced repair activity in the satellite DNA. We have measured the extent of binding of 14C-methyl methanesulfonate to the satellite, and main band DNA, and no difference in binding was observed, indicating that the reduced repair activity of satellite DNA is not due to a difference in binding of alkylating agents. We believe that the reduced incorporation of 3H-Tdr into satellite DNA may be due to its location in the condensed chromatin fraction.

Animals↗
PubMed1976

Cell cycle-related hormone carcinogen interaction during chemical carcinogen induction of nodule-like mammary lesions in organ culture.

The immature mammary glands of BALB/c female mice were treated with 7,12-dimethylbenz[a]anthracene (DMBA), 2 micrograms/ml, or 3-methylcholanthrene (10 micrograms/ml) for a 24-hr period at different times during the inital six days of lobuloalveolar growth in hormone-supplemented organ culture. Nodule-like alveolar lesions (NLAL) were detectable in 80% of the glands treated with DMBA (40% in 3-methylcholanthrene-treated glands) in the presence of insulin + prolactin + aldosterone + cortisol in the medium. No NLAL were present in dimethyl sulfoxide-treated control glands cultivated with the same hormones. The hormone combination insulin + prolactin + cortisol was unfavorable for NLAL induction by DMBA, and the combination of aldosterone + insulin + prolactin was only moderately conducive. Thus, the presence of cortisol with insulin + prolactin + aldosterone enhances NLAL incidence of mammary cells by DMBA. The highest incidence was found in glands that were treated with DMBA for 24 hr between the third and fourth day of culture, the period corresponding to the onset of the second wave of DNA synthesis in the gland. Cytotoxicity of DMBA was pronounced between 24 and 48 hr, when a high frequency of cells were in DNA synthesis, and survival of the cells after the cytotoxic effect of DMBA appeared to play a role in NLAL incidence. This suggests that DMBA-induction of NLAL in mammary glands in organ culture involves a complex carcinogen-hormone-cell cycle interaction. We emphasize that, although NLAL morphologically resembles the hyperplastic alveolar nodules of mouse mammary gland in vivo, the abilitity of NLAL to produce typical hyperactive alveolar outgrowth and mammary tumor after transplantation iv vivo remains to be determined.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1975

An indirect radioimmunoassay for mouse casein using 125I-labeled antigen.

A new indirect radioimmunoassay was developed for detection of casein in mouse milk and in mammary tissue extract. Preincubation of rabbit gamma globulin to mouse milk casein (Ca2+-rennin precipitate) with unlabeled casein, milk, extracts of mammary tissues of late pregnancy and lactation, virtually blocked subsequent binding of 125I-labeled mouse milk casein to the antibody. Preincubation with mouse serum, bovine serum albumin, rennin, extracts of liver or immature mammary tissue had little effect on [125I]casein binding to the antibody. The inability of [125I]casein to bind to the antibody after preincubation with protein samples, which are likely to contain casein, is indicative of a specific antigen-antibody reaction. The assay is capable of detecting 0.2 mug casein, 1 mug milk proteins and 10 mug lactating mammary tissue extract. The application of the assay was also demonstrated using organ culture of the entire mammary gland. The glands treated with the lactogenic hormones, insulin + prolactin + cortisol, showed a saturation level of antibody-antigen reaction, indicating hormonal induction of casein; whereas, no reaction was observed with the non-treated gland.

Animals↗
PubMed1975

Murine mammary gland RNA directed synthesis of casein in a heterologous cell-free protein synthesis system.

A cell-free protein synthesis system derived from Ehrlich ascites tumor cell ribosomes (S30) plus rabbit reticulocyte tRNA was developed and the activity of the system was dependent on rabbit reticulocyte ribosomal salt (0.5 M KC1) wash factors, The exogenous mRNAs from BALB/c mouse liver and the mammary gland were translated with a high efficiency in this heterologous cell-free system. Furthermore, the RNA from the lactating mammary gland faithfully directed the synthesis of casein. The presence of mouse casein in the reaction product was identified by radioimmunoprecipitation with mouse casein antiserum, co-electrophoresis of the reaction product and mouse casein the urea-polyacrylamide gel and by electrophoresis in sodium dodecyl sulfate (SDS) polyacrylamide gel. The major portion of the lactating mammary gland RNA directed synthesis of the milk protein in the cell-free system appeared to be analogous to alphas casein,

Animals↗
PubMed1975

Action of growth-promoting hormones on macromolecular biosynthesis during lobulo-alveolar development of the entire mammary gland in organ culture.

The entire 2nd thoracic mammary gland of the immature virgin BALB/c mouse was stimulated to full lobulo-alveolar (LA) growth after 120 h organ culture in hormone supplemented medium. The minimal hormonal combination required was insulin (I) + prolactin (Prl) + aldosterone (A). The corticosteroid was replaceable by oestradiol-17beta (E) + progesterone (P). The combination I alone or I + the steroid hormone(s) failed to induce the LA development and similar results were also evident in presence of Prl + the steroids. Incubation of the glands in medium with I + Prl + A activated a sequential rise of RNA, protein and DNA synthesis. A near maximal increase of RNA synthesis was present at 48 h in the medium with I + Prl, addition of the steroid hormones did not show further stimulatory effect. Supplementation of the medium with I + Prl and the adrenal or the ovarian steroids was needed for maximal activation of protein synthesis at 72 h and DNA replication at 96 h. The medium with I alone did not show a substantial rise of macromolecular biosynthesis in the mammary gland in organ culture. The highest level of DNA polymerase activity was observed at 72 h in glands cultivated in medium with I + Prl and A or E + P. Only a modest increase of DNA polymerase activity was present in glands cultivated with I alone or I + Prl. Prior treatment of the glands (cultivated with I + Prl + A) with actinomycin D or puromycin resulted into 44 and 40% reduction of DNA polymerase activity suggesting hormone-induced synthesis of the enzyme before the rise of DNA synthesis in the mammary cells at 96 h in organ culture. Significance of these results with respect to the action of the "growth-promoting" hormones in the mammary gland in organ culture and in the animal has been discussed.

Aldosterone↗
PubMed1975

Hormonal regulation of lobulo-alveolar growth, functional differentiation and regression of whole mouse mammary gland in organ culture.

The entire second thoracic mammary glands of 4-week-old BALB/c female mice primed with oestradiol plus progesterone were cultivate in organ culture medium containing the "growth-promoting" hormone combinations: insulin, prolactin, growth hormone, oestradiol, progesterone and aldosterone or insulin, prolactin and aldosterone. Full lobulo-alveolar development was induced after 5-6 days of incubation and could be maintained for 15-16 days in organ culture in medium containing either hormone combination. After the initial 5-6 days in the "growth-promoting" medium, subsequent cultivation of the glands in a medium with the "lactogenic hormones", insulin, prolactin plus cortisol, led to accumulation of "milk-like" secretory material in the ductal and alveolar lumina. Incubation of the lobulo-alveolar gland in medium with insulin alone for 7-9 days resulted in complete regression of the alveoli leaving only a ductal parenchyma. Incubation in insulin, prolactin, growth hormone or insulin plus the steriod hormones for 7-9 days led to considerable alveolar degeneration without a complete regression. The results indicate that both pituitary and steroid hormones are essential for development and maintenance of mammary alveoli; insulin can only sustain the basal ductal structure.

Aldosterone↗