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Biomedical subjects

A B Mukherjee

Publications and source records attributed to A B Mukherjee.

At least 127 records · Page 7Linked to original sources
PubMed1983

Double minutes and other chromosomal aberrations in two malignant cell lines of the German cockroach Blattella germanica.

Structural anomalies of mitotic chromosomes from two tumorigenic cell lines of the German cockroach (Blattella germanica) is described. Aberrations, such as unpairable marker chromosomes, double minutes, di- and tricentrics, ring chromosomes, tri- and quadriradials, and chromosome and chromatid gaps and breaks, were observed in varying proportions. This study reports that the double minute chromosomes (DMs) are associated with insect tumor cells, similar to the findings in both murine and human tumor cells.

Animals↗
PubMed1983

Liposome-mediated transfer of simian virus 40 DNA and minichromosome into mammalian cells.

We have investigated the use of liposomes as carriers for the transfer of simian virus 40 (SV40) DNA into mammalian cells. The amount of DNA entrapped in liposomes was dependent on the input DNA concentration and lipid composition. DNA remained intact after liposome encapsulation and was resistant to deoxyribonuclease digestion. Combined transfer to and expression of liposome-entrapped SV40 DNA in monkey kidney cells was assayed by infectious plaque formation. Negatively-charged liposomes containing phosphatidylserine were more effective in DNA transfer and expression than neutral liposomes. The inclusion of carrier salmon sperm DNA inhibited liposome-entrapped SV40 DNA infectivity. Infectivity of liposome-entrapped DNA was directly related to both liposome DNA concentration and number of vesicles added. Liposome-entrapped SV40 minichromosome was 20-fold more infective than free minichromosome, but only 20% more infective than liposome-entrapped SV40 DNA. Thus, the presence of hyperacetylated histones on the DNA failed to enhance liposome-mediated DNA transfer appreciably. Incubation of cells with various modulators of endocytosis implicated the endocytotic pathway in the mechanism of liposome-mediated DNA transfer. These studies show that liposomes are suitable carriers for the introduction of viral DNA and chromatin into mammalian cells.

Animals↗
PubMed1982

Maternal ethanol exposure induces transient impairment of umbilical circulation and fetal hypoxia in monkeys.

When ethanol was administered intravenously to pregnant monkeys, a transient but marked collapse of umbilical vasculature was observed uniformly within about 15 minutes. The ethanol-induced impairment of umbilical circulation produced severe hypoxia and acidosis in the fetus; recovery occurred during the succeeding hour. This striking interruption of feto-placental circulation may explain one of the mechanisms of mental retardation, a frequent manifestation in children afflicted with fetal alcohol syndrome.

Acetaldehyde↗
PubMed1982

Transfer of murine leukaemia and murine sarcoma virus genetic information by transfection with isolated metaphase chromosomes.

Chromosome-mediated transfer of murine leukaemia (MuLV) and murine sarcoma (MuSV) virus genetic information to uninfected recipient cells was investigated. Metaphase chromosomes from AKR MuLV-infected SC-1 mouse cells were incubated with NIH/3T3 cells. After several passages (1 to 3 weeks), infectious virions exhibiting reverse transcriptase activity and the characteristic host range of ecotropic, N-tropic AKR virus appeared in the supernatant fluids of the treated cells. Restriction endonuclease analysis of genomic DNA from transfected cells indicated that AKR proviral DNA was associated with the high molecular weight DNA of the host. These results demonstrate that the AKR MuLV genome can be stably transferred to uninfected recipient cells via isolated metaphase chromosomes. Although AKR virions are not able to infect heterologous cells, chromosome-mediated transfection resulted in the establishment of productive AKR MuLV infection in mink cells. Thus, the use of chromosomes to transfer virus genes can circumvent the natural host restriction barrier. In other experiments, it was shown that normal NIH/3T3 cells were transformed after exposure to metaphase chromosomes isolated from an MuSV-infected, non-producer line. Foci were detected 14 to 21 days after chromosome treatment and were shown to contain true viral transformants since transforming virus was produced after superinfection with MuLV.

Animals↗
PubMed1982

Role of uteroglobin and transglutaminase in masking the antigenicity of implanting rabbit embryos.

Using rabbit as a model, the roles of uteroglobin (UG) and transglutaminase (TG) in masking the antigenicity of early developing mammalian embryo have been investigated. Maternal lymphocytes in vitro, when mixed with mitomycin-C inactivated blastomeres, incorporated H3-thymidine, suggesting recognition of embryonic antigens by these cells. However, pretreatment of blastomeres with pregnant uterine fluid (PUF) or with UG alone or in combination with TG (coagulation factor XIIIa), resulted in a significant and dose-dependent suppression of H3-thymidine incorporation into these lymphocytes. A complete suppression was achieved at a concentration of 250 micrograms of UG/ml, in the absence of TG. However, in the presence of TG, only 1.0 micrograms of UG/ml was required for total suppression. Neither nonpregnant uterine fluid (NPUF), nor myoglobin, a nonspecific protein similar in molecular weight to UG, had any suppressive effect. Incubation of uteroglobin with anti-UG or TG with its antiserum prior to the pretreatment of blastomeres eliminated the suppressive effect of these proteins. Inhibition of TG by neopentyl chloroethyl nitrosourea (NPCNU) also eliminated the suppressive effects of uteroglobin on H3-thymidine incorporation into maternal lymphocytes. These results suggest that in the pregnant uterus UG in conjunction with TG may play a specific role in masking the antigenicity of developing embryos during implantation.

Animals↗
PubMed1981

Superovulation-induced intrauterine growth retardation in mice.

Existing animal models for inducing intrauterine growth retardation (IUGR) involve severe maternal compromise or acute fetal insult. We postulated that superovulation would produce IUGR gradually by enhancing fetal competition for nutrients. Mice were superovulated with pregnant mare serum and human chorionic gonadotrophin and killed on day 19 of gestation. Compared to controls, the mean number of fetuses was significantly increased; body, brain, liver, and placental weights were reduced; and brain/liver weight ratios were increased. Additional mice underwent partial unilateral oophorectomy before superovulation. Marked asymmetry in the number of fetuses in the two uterine horns of the same mother was produced, and the fetuses on the more crowded side manifested smaller brains and livers an increased brain/liver ratios. In the mouse, superovulation is a simple, preconceptual method for achieving IUGR and may be combined with partial unilateral oophorectomy to permit comparisons between fetuses with different growth characteristics within the same mother.

Animals↗
PubMed1981

Dysplastic cutaneous osteomatosis. A unique case of true osteoma.

A unique cas of dermal calcification occurred in a 14-month-old femal infant. Results of all pertinent laboratory data obtained on this patient were within normal limits except for an elevation of the heat labile fraction of alkaline phosphatase. A skin biopsy specimen showed irregularly shaped deposits of calcified osteoid with osteoblasts. As yet, neither the cause nor the prognosis of this disease has been delineated.

Calcinosis↗
PubMed1981

Lipochromosome mediated gene transfer: identification and probable specificity of localization of human chromosomal material and stability of the transferents.

Using lipochromosomes (phospholipid-entrapped chromosomes) were have transferred the human HGPRT gene into HGPRT deficient mouse cells (A9) with a frequency of approximately 1 x 19(-5) (Mukherjee et al. Proc. Natl. Acad. Sci. USA 75: 1361-1365; 1978). Two other genes located on the long arm of the human X-chromosome were also expressed two independently derived populations of transferents (A9/GT3 and A9/GT4). We report here the chromosomal and enzymatic composition of human HGPRT-positive clones from each subpopulation analyzed in detail with alkaline Giemsa-11 staining. All the clones expressed human PGK and HGPRT, but one (A9/GT4C6) lacked human G6PD. In each of four clone examined microscopically, a small piece of presumptive human chromatin was visible in the karyotypes of most cells. The chromatin fragment was free or attached in each cell of an individual clone. When integrated, the human chromosomal fragment in each clone appeared associated with the centromere of the same telocentric A9 chromosome (No. 6 Q-banding). These data suggest that: (a)substantial human chromosomal fragments can be transferred into recipient cell using the lipochromosome technique; (b) clones from human HGPRT positive A9 transferent subpopulations may or may not possess other human X-linked markers: (c) the stability of lipochromosomally transferred genes varied from clone to clone and stability is generally poor in the absence of continuous selection pressure (e.g., HAT); (d) when multiple X-linked human genes were transferred to mouse cells a cytologically detectable human chromosomal fragment was identified free or attached to a host chromosome; and (e) integration of transferred human chromosomal material into mouse chromosomes may occur at preferential site(s) in the recipient genome.

Animals↗
PubMed1981

Pantetheinase activity and cysteamine content in cystinotic and normal fibroblasts and leukocytes.

Cysteamine is the most effective agent known for the reduction of the elevated cystine content of cells from patients with cystinosis. A defect in endogenous cysteamine generation could account for many of the metabolic features of this disorder. To test this hypothesis, we have developed improved methods for measuring pantetheinase (cysteamine-generating) activity and intracellular cysteamine levels and used these methods to measure such parameters in cystinotic and normal leukocytes and cultured skin fibroblasts. Pantetheinase activity as defined in the test was similar in extracts of cystinotic and normal cells [leucocytes, normal, 78 +/- 15 (S.E.), cystinotic, 56+/- 6.4; fibroblasts, normal, 9.4 +/- 1.5; cystinotic, 7.7 +/- 1.7]. Cysteamine levels were normal in leukocytes from cystinotics receiving no cysteamine or doses of oral cysteamine too low to reduce leukocyte cystine content. The results indicate that the cause of cystinosis is unlikely to be related to a failure to generate of sustain normal intracellular cysteamine levels.

Amidohydrolases↗
PubMed1980

Cystinotic and normal fibroblasts: differential susceptibility to cysteine toxicity in vitro.

Extracellular cysteine concentrations between 0.5 and 2.5 mM resulted in death of normal but not cystinotic cells grown in Eagle's minimal essential medium containing supplemental fetal bovine serum and antibiotics. Differential cell survival was determined by viable cell counting using Trypan Blue dye exclusion. In cocultivation experiments of [3H]thymidine-labelled cystinotic fibroblasts with nonradioactive normal fibroblasts, autoradiography confirmed the selective survival of cystinotic cells in medium containing 1 mM cysteine. At this concentration of 1 mM cysteine, intracellular cystine content increased slightly in surviving normal cells but not in cystinotic cells, which normally contain a high level of intracellular cystine. This comparative resistance of cystinotic fibroblasts to elevated extracellular cysteine concentrations forms the basis for an in vitro selective system for these mutant human cells. Further exploration of this resistance phenomenon may well expand the understanding of the molecular defect in cystinotic cells.

Cell Count↗
PubMed1980

Possible mechanism of success of an allotransplantation in nature: mammalian pregnancy.

A new hypothesis is presented to explain the mechanism of non-rejection of a natural allograft: the mammalian fetus during early development. Using the rabbit as a model, it is proposed here that uteroglobin (UG., MW. 15,800) synthesized in the uterus during early pregnancy, crosslinks with beta 2-microglobulin (part of the H-2 and HL-A antigens) on the embryonic cell surface. This crosslinking is achieved by the enzyme transglutaminase (coagulation factor XIIIa), which has a 4--5 fold increased activity in the uterus during early pregnancy. The conversion of pre-uteroglobin (Pre-UG) to uteroglobin (UG) and pro-transglutaminase (factor XIII) to active transglutaminase (factor XIIIa) is achieved by the concurrent increased activity of proteases present in the uterus at this time. UG is a dimeric protein with two alpha-helices running in parallel and connected by two disulfide bonds. We propose that UG molecules crosslink with beta 2-microglobulin in the presence of transglutaminase (factor XIIIa). A crosslinked beta 2-microglobulin-uteroglobin complex is formed which masks the H-2 or HL-A antigen of the implanting embryo. Thus, the maternal lymphocytes do not recognize the fetal cells as foreign. This mechanism may also explain the non-immunogenicity of ejaculated sperm in the uterus, as well as the non-immunogenicity of fetal cells found in the maternal circulation during pregnancy. At later stages of pregnancy, other proteins and/or hormones as well, may play a role in non-rejection of the fetus. However, the beta 2-microglobulin-uteroglobin complex masking the transplantation antigens of the embryo may be the major mechanism for immunological protection and non-rejection of the implanting embryo.

Animals↗
PubMed1979

Survival of transplanted normal hepatic cells in bilirubin UDP-glucuronyl transferase deficient Gunn rat liver.

The survival of H3 thymidine labelled normal rat hepatic cells after transplantation into the Gunn rat liver has been investigated. It was found that 0.9% of the cells survived at least 12 weeks after transplantation. This suggests that the observed uridine diphosphoglucuronyl transferase (UDPGT) activity in the genetically deficient Gunn rats after transplantation of normal liver may be partially due to these cells. Time required for the transplantation procedure has a profound effect on the survival of such cells in the recipient liver.

Animals↗
PubMed1978

Entrapment of metaphase chromosomes into phospholipid vesicles (lipochromosomes): carrier potential in gene transfer.

Transfer of genes from one type of cultured mammalian cell to another by using isolated metaphase chromosomes has been reported with a frequency of one per 10(6)-10(8) cells. Very recently a rate of 16/10(6) has been reported with Chinese hamster ovary cells [Spandidos, D. A. & Siminovitch, L. (1977) Proc. Natl. Acad. Sci. USA 74, 3480-3484]. To increase the frequency of gene transfer, we isolated metaphase chromosomes from hypoxanthine guanine phosphoribosyltransferase (HGPRT) positive cells, entrapped them in liposomes, and fused the lipochromosomes with HGPRT-negative cells. Lipochromosomes were prepared with cholesterol and egg lecithin, using isolated metaphase chromosomes from a mouse-human somatic hybrid cell line (A9/HRBC2); the entire X chromosome, including the HGPRT, glucose-6-phosphate dehydrogenase, and phosphoglycerate kinase genes, is the only recognizable human genetic material retained by the hybrids. Enclosure of the chromosomes in the lipid envelope was confirmed by electron and fluorescence microscopy and differential centrifugation. These lipochromosomes were fused with HGPRT(-) mouse cells (A9) in the presence or absence of polyethylene glycol and transferents were selected in hypoxanthine/aminopterin/thymidine (HAT) medium. The frequency of transfer was at least once per 10(5) cells, a minimum 10-fold improvement over previous methods. The selected cells contained HGPRT activity similar to the amount found in the A9/HRBC2 cells. Starch gel electrophoresis verified that the observed HGPRT activity in the transferents is due to the human enzyme. Human glucose-6-phosphate dehydrogenase and phosphoglycerate kinase were also identified electrophoretically in the transferents. Karyotyping with C and Q banding did not reveal the presence of the whole human X chromosome or a visible extra fragment of a human chromosome associated with the mouse genome. The biochemical data strongly suggest, however, that transfer of a portion of the human X chromosome has occurred in these transferents. Thus, at least three X-linked genes have been transferred from one cell to another with high frequency, using metaphase chromosomes.

Cell Line↗
PubMed1978

The cell cycle of an established cell line of the mosquito Aedes aegypti.

The duration of the cell cycle and its four phases was determined for a cell line of the mosquito, Aedes aegypti (L.), using high-resolution autoradiography. The total cell cycle time is 12.5 h, with G1 comprising 1.66 h, S--4.5 h, M--3 h, and G2 3.33 h. These results are compared with those of other mosquito species.

Aedes↗