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Biomedical subjects

D Bulmer

Publications and source records attributed to D Bulmer.

At least 19 recordsLinked to original sources
PubMed1993

Characterization of a new bacteriophage which infects bacteria of the genus Acidiphilium.

A novel bacteriophage, termed phi AC1, that infects strains of the genus Acidiphilium (acidophilic, heterotrophic, aerobic, Gram-negative eubacteria) most commonly isolated from acidic mine drainage environments, has been discovered and several of its properties have been determined. This is the first report of a bacteriophage infecting such cells. The virion has a lambdoid morphology and is larger than lambda, as shown by electron microscopy and sucrose gradient centrifugation. The sedimentation coefficient of the virion is approximately 615S. The nucleic acid of phi Ac1 is dsDNA, approximately 102 kb in length. Several experimental results show that phi Ac1 is a temperate phage. The plaques are turbid, and most cells isolated from plaques produced on sensitive cells by filter-sterilized phage preparations contain the phage and are resistant to further phage infection. Southern blot analysis shows that phi Ac1 prophage DNA is integrated into the bacterial genome during the temperature growth phase.

Bacteriophages↗
PubMed1987

The metrial gland.

The information available about the metrial gland of the pregnant rodent uterus with its content of granulated metrial gland (GMG) cells is reviewed. Recent research shows that GMG cells differentiate from bone marrow cells and supports the suggestion that GMG cells are involved in the immunological relationship between mother and foetus. There is probably a complex association between GMG cells and stromal cells of the metrial gland, and it is suggested that the association between GMG cells and the placental labyrinthine cells represents a functional interaction.

Animals↗
PubMed1986

Effects of exogenous progesterone following ovariectomy on the metrial glands of pregnant mice.

The numbers of granulated metrial gland cells, the percentage of them incorporating tritiated thymidine and the numbers of granulated metrial gland cell precursors in a defined area of the metrial gland, and the cross sectional area of the metrial gland, have been determined in mice ovariectomised on Day 8 of pregnancy. The effects, on these parameters and on fetal survival, of progesterone treatment, given at two levels (0.5 mg or 1 mg twice daily) and started immediately after ovariectomy or after 6, 10 or 24 hours delay, have been studied. Granulated metrial gland cell number, DNA synthetic activity and metrial gland size decreased rapidly after ovariectomy but there was a significant increase in the number of granulated metrial gland cell precursors in the first 24 hours. Progesterone treatment, at the higher dose level started immediately after ovariectomy, resulted in significantly more granulated metrial gland cells in the area analysed two days after ovariectomy although a normal proportion of them were in DNA synthesis. Immediate progesterone treatment, at the higher dose level, was able to prolong the DNA synthetic activity of granulated metrial gland cells until Day 19 and this probably accounted for the significantly greater numbers of granulated metrial gland cells in these mice than in control mice, at this time. Delaying progesterone treatment at the higher level by 24 hours significantly reduced the size of the metrial glands at Day 10 but there was no effect on the cellular composition of the area analysed. Delaying the lower dose of progesterone treatment by 24 hours also resulted in small metrial glands and was associated with significantly fewer granulated metrial gland cells in the area analysed but significantly more of them were synthesising DNA. The observations are discussed and an attempt is made to relate the effects on individual fetal and placental survival to the effects on the corresponding metrial glands.

Animals↗
PubMed1983

Experimental evidence for the bone marrow origin of granulated metrial gland cells of the mouse uterus.

The clear morphological differences between the granulated metrial gland (GMG) cells which develop in the uteri of rats and mice have been used to assess the origin of GMG cells in radiation chimaeras. Lethally irradiated mice were reconstituted with either rat or mouse bone marrow cells. Control mice were ovariectomised. A schedule of steroid injections was carried out allowing deciduoma formation to be induced in the irradiated and control animals. Deciduoma formation was impaired, and there were few GMG cells in the irradiated, bone marrow-reconstituted mice in comparison with the ovariectomised controls. However, it was possible to identify, by their distinctive morphology, 1) rat GMG cells in the mice reconstituted with rat bone marrow cells, and 2) mouse GMG cells in the mice reconstituted with mouse bone marrow cells. Conversely, no typical mouse or rat GMG cells were identified in mice reconstituted, respectively, with rat or mouse bone marrow cells. The observations indicate that GMG cells differentiate from a precursor derived from bone marrow.

Animals↗
PubMed1983

The effects of ovariectomy and subsequent progesterone replacement on the uterus of the pregnant mouse.

The effects of ovariectomy at day 8 of pregnancy were studied on the granulated metrial gland cells of the mouse uterus, with and without subsequent progesterone replacement. By one day after the ovariectomy the fetuses were dead and there was extensive decidual necrosis. Though numerous granulated cells were still present after one day, accompanied by an extensive polymorphonuclear leucocytosis in the mesometrial triangle, granulated cells virtually disappeared within three days. In animals injected with 1 mg progesterone twice daily over five days, starting at the time of ovariectomy, the pregnancies survived. There was no decidual necrosis, and the numbers, morphology and distribution of the granulated metrial gland cells were normal. In ovariectomised animals injected with 0.5 mg progesterone twice daily most implantation sites after three, four and five days were associated with fetal death, though numerous granulated metrial gland cells survived. In implantation sites where the fetus had survived to thirteen days, there were markedly fewer granulated cells than in implantation sites either from control animals or from animals treated with the higher dosage of progesterone. Cytoplasmic granules in stromal cells of the metrial gland were prominent in the ovariectomised animals. They were much less numerous in animals given the lower dosage of progesterone and absent from those given the higher dosage.

Animals↗
PubMed1983

Endometrial granulocytes of the pregnant hamster.

The appearance and distribution of endometrial granulocytes in the pregnant hamster were studied by light and electron microscopy. They first appeared in the tissue spaces of the mesometrial decidua and in the decidual sheaths of the spiral arteries. At the base of the mesometrial triangle they were restricted to the cellular sheaths of the arterial channels supplying the chorio-allantoic placenta and were not diffusely distributed throughout the mesometrial triangle. The endometrial granulocytes of the pregnant hamster uterus appear to be similar in structure and distribution to the granulated metrial gland cells of rats and mice and are not restricted, as previous literature suggests, to the walls of arterial channels.

Animals↗
PubMed1981

The persistence of placental remnants, beyond the normal period of gestation, in rats ovariectomised at day 12 of pregnancy.

The uterus, mammary glands and vaginal epithelium were examined in rats ovariectomised at day 12 of pregnancy and killed between 10 and 16 days later, and in a group of normal post partum rats. All the animals were injected with tritiated thymidine one hour before death. Some placental remnants persisted in all the ovariectomised animals and were associated with incorporation of tritiated thymidine in the uterine epithelium and smooth muscle. A pronounced cellular infiltration occurred in the endometrium and metrial gland of the normal post partum animals, with a marked increase in nuclear labelling. In comparison, the cellular reaction in the endometrium of the ovariectomised animals was delayed and very much reduced, and there was no reaction in the metrial gland. The breasts of the ovariectomised animals were secreting up to 12 days after operation; in all the ovariectomised animals the vaginal epithelium was of low, stratified squamous form, with nuclear labelling in the basal layers. The results are discussed in relation to the possible endocrine environment prevailing in the ovariectomised animals, and in relation to the possible factors affecting the influx of blood-borne cells to the uterus.

Animals↗
PubMed1979

The effects on the rat uterus and placenta of ovariectomy at day 10 of pregnancy.

A study was made of the changes in morphology and in nuclear incorporation of tritiated thymidine in the rat uterus and placenta after ovariectomy at day 10 of gestation. There was some individual variation between different animals in the results of the ovariectomy, but in general the effects on both maternal and fetal tissues were more severe than those reported to follow ovariectomy at later stages of pregnancy. Even in the animals where there was extensive placental survival 2 or 3 days after the ovariectomy, normal differentiation of the placental labyrinth did not occur and the fetuses failed to survive. Ovariectomy had a pronounced effect on the proliferative activity of uterine epithelial cells. The high labelling index in the control animals up to day 12 was markedly reduced in the ovariectomized animals; after day 13, however, the labelling index of the controls was reduced to a level lower than that of the ovariectomized animals. Nuclear labelling occurred in the glandular epithelium from two days after ovariectomy, but was never present in the controls. There was a marked reduction in the percentage of labelled nuclei in the uterine muscle and in the metrial gland after ovariectomy. In the metrial gland this was associated with a reduction in the number of typical granulated cells and with the appearance of numerous small round cells. It is suggested that the latter represented metrial gland cell precursors which had undergone impairment of their normal differentiation process.

Animals↗
PubMed1979

Metrial gland cells in deciduomata of pseudopregnancy.

Light and electron microscope studies were carried out on the metrial gland cells of deciduomata of pseudopregnancy in the rat. At the light microscope level these cells were characterised by a comparatively pale staining cytoplasm with numerous glycoprotein granules. Some also had extensive cytoplasmic deposits of glycogen. In electron micrographs the metrial gland cell cytoplasm as a whole was much less electron-dense than that of fibroblasts and decidual cells, but it contained densely stained pleomorphic granules. There were stacks of rough endoplasmic reticulum, oval or round profiles of fibroblasts and decidual cells, but it contained densely stained pleomorphic granules. There were stacks of rough endoplasmic reticulum, oval or round profiles of mitochondria, and an extensive Golgi network. The metrial gland cells were roughly spherical in appearance, with irregular surface projections. In all these features, and in the sequence of their appearance, first in the decidua basalis, and later in the mesometrial triangle, the granulated metrial gland cells of deciduomata resembled the metrial gland cells of pregnancy. In addition to granulated metrial gland cells, decidual cells and fibroblasts, a number of other cell types were identified. These cells could be placed in a series, with each member of the series minimally different in morphological appearances from its neighbours. It is proposed that the series represents the differentiation of granulated metrial gland cells, in situ, from lymphocyte-like cells. The differentiation from a lymphocyte precursor appears to follow a sequence in deciduomata formation similar to that previously described in pregnancy.

Animals↗
PubMed1977

Proliferation and differentiation of trophoblast in the establishment of the rat chorio-allantoic placenta.

The morphological differentiation of the elements contributing to the chorioallantoic placenta of the rat was studied between days 6 and 16 of gestation, and DNA synthetic activity was investigated in animals killed 1 hour after injection of tritiated thymidine. The chorionic lamina is formed from the epithelial cells lining the ectoplacental cavity, though it is possible that a contribution is made by ectoplacental cone cells at the mesometrial pole of the cavity. From day 8 onwards a high proportion of cells was labelled in both cone and lamina, with the labeliing index reaching a peak of about 80% at 10-11 days. There was no corresponding peak in mitotic activity, which remained at a high level in all regions up to day 12. The amount of thymidine incorporation, as judged by grain count per nucleus, varied. At 9 days a significantly higher grain count was obtained in a central core of cells in the ectoplacental cone, and at day 10 the grain density of labelling in the cone was very much heavier than in the lamina. This difference in labelling intensity was maintained until day 12, and there was no evidence of any influx of heavily labelled cells from the cone into the developing labyrinth.

Allantois↗
PubMed1977

The fine structure of the rat metrial gland in relation to the origin of the granulated cells.

The fine structure of the metrial gland of the rat was examined at days 12, 14, 16, 18 and 20 of pregnancy and at all these stages two well differentiated cell types were seen. A relatively pale-staining cell which contained numerous dense granules was readily distinguished from a darkly stained fibroblast-like cell. Numerous cells could be identified, however, which did not fit either of these categories. On the basis of their morphological appearances these cells were placed in a series, with the members of the series showing a transition from a small cell with a high nuclear/cytoplasmic size ratio to a readily identifiable metrial gland cell containing a few typical granules. The small cell, apparently the precursor of the granulated metrial gland cell, was characterized by a markedly heterochromatic nucleus and few cytoplasmic organelles, although there were occasional mitochondria and Golgi bodies. On morphological grounds this cell appeared to be from the lymphocyte series and was probably a small lymphocyte.

Animals↗
PubMed1976

Bromodeoxyuridine induced variations in the level of alkaline phosphatase in several human heteroploid cell lines.

The level of alkaline phosphatase in a number of established cell lines of human origin can be modified by exposure to non-lethal concentrations of bromodeoxyuridine (BRdU). In the several cell lines examined an inverse relationship between amount of induction and constitutive level of the enzyme was observed. Thus, the H.Ep 2 line, which had the highest basal level of enzyme, was reversibly repressed following exposure to the drug, whereas other cell lines with relatively low constitutive enzyme levels were induced to a maximum of 10-fold following exposure. Initiation of induction required from 24 to 48 hours, and as short an exposure ("pulse") as five hours was sufficient to produce induction. Exposure to visible light had no effect upon the repression of alkaline phosphatase in H.Ep 2 by BRdU. Induction did not occur in non-dividing, serum starved cells. The time course of induction by BRdU and hydrocortisone was similar, and simultaneous exposure of the cells to both agents resulted in no greater induction than that observed with either drug alone. Experiments utilizing mitomycin C yielded significant induction in the presence of this agent alone, and somewhat less induction when both mitomycin C and BRdU were added simultaneously. These results suggest that DNA synthesis is required for BRdU were added simultaneously. These results suggest that DNA synthesis is required for BRdU-mediated induction of alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1975

The effects of late ovariectomy on the proliferation and differentiation of the uterus of the pregnant rat.

The effects of ovariectomy at day 12 of pregnancy on the proliferative activity of the uterine epithelium, metrial gland and uterine muscle in the rat were studied by autoradiography in animals killed one hour after a single injection of tritiated thymidine. The results were amplified by histological and histochemical studies. One day after operation epithelial proliferation was impaired in the ovarectomized animals. From 16 days onwards, however, proliferative activity was at a lower level in controls than in the ovariectomized animals. Three days after ovariectomy uptake of tritiated thymidine by metrial gland cells was less than in the controls. The metrial gland became smaller after ovariectomy and showed histological and histochemical changes from the normal pattern. The increased thickness of the uterine muscle in the ovariectomized animals from the 16 day stage onwards was not associated with any significant change in the labelling index of the muscle cells. The results are discussed in relation to the changes in endocrine environment which may occur after ovariectomy.

Animals↗