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Biomedical subjects

I Stewart

Publications and source records attributed to I Stewart.

At least 91 records · Page 5Linked to original sources
PubMed1984

Infusion cholecystography in the early diagnosis of acute gallbladder disease.

The value of infusion cholecystography 99mTc HIDA cholescintigraphy and ultrasonography was compared in 51 patients presenting with a clinical diagnosis of acute cholecystitis. Of the 35 patients with proven gallbladder disease, the presence of gallstones was correctly predicted in 31 (88 per cent) by infusion cholecystography, 32 (90 per cent) by 99mTc HIDA cholescintigraphy and 27 (77 per cent) by ultrasonography. There were no false positive investigations. Infusion cholecystography may be of particular interest to surgeons with no ready access to isotope scanning techniques.

Acute Disease↗
PubMed1984

The differentiation of granulated metrial gland cells in chimeric mice and the effect of uterine shielding during irradiation.

The differentiation of granulated metrial gland (GMG) cells has been investigated during deciduomata formation in radiation-induced chimeric mice reconstituted with rat or mouse bone marrow. The extent of the decidual reaction was apparently normal in regions of the uterine horns shielded from the irradiation but was impaired in, or absent from, the irradiated horns. The numbers of GMG cells which differentiated varied but were greater in the larger decidual swellings. The distinct morphological differences between rat and mouse GMG cells were used to analyse the GMG cells which differentiated in mice reconstituted with rat bone marrow. Only rat GMG cells were identified in the unshielded horns showing that bone marrow cells provide precursors for GMG cells. However, both rat and mouse GMG cells were found in the horns shielded from the irradiation. This indicates that some precursors for mouse GMG cells are present in the uterus at the time of the irradiation and are protected by the lead shield to survive and differentiate in situ. Furthermore they do not circulate to replace the precursors killed in the unshielded horn.

Animals↗
PubMed1984

A morphological study of granulated metrial gland cells and trophoblast cells in the labyrinthine placenta of the mouse.

A study has been made, using light and electron microscopy, of GMG cells in the labyrinthine placenta of the mouse. GMG cells were found lying within the lumina of the maternal blood spaces showed degenerative changes and GMG cells were usually found close to these degenerate trophoblast cells. Sometimes the GMG cells also showed degenerative changes. The observations suggest that an interaction may take place between GMG cells and layer 1 trophoblast cells and support the idea that the labyrinthine placenta is a site of functional significance to GMG cells.

Animals↗
PubMed1983

An investigation into the differentiation of granulated metrial gland cells in the early pregnant mouse uterus.

A study has been made of the influence of semen, blastocysts and the nidatory hormones on the differentiation of mouse granulated metrial gland cells in the peri-implantation period. The results indicate that the nidatory hormones, but not semen or blastocysts, are associated with the differentiation of granulated cells in the peri-implantation period. The possibility that the differentiation of granulated cells is under the control of the hormone-sensitive stromal cells rather than under the direct control of ovarian hormones is discussed.

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↗
PubMed1982

Changes in the cell population of the pregnant rodent uterus in relation to the differentiation of granulated metrial gland cells.

A time-lapse autoradiographic study has been made of changes in the cell population of the decidua basalis during its development in the mouse, in order to investigate the origin of granulated metrial gland cells. Granulated metrial gland cells initially formed less than 1% of the cells but during the period of study they increased in number to form 14% of the cells. The proportion of unlabelled lymphocyte-like cells and granulated metrial gland precursor cells fell significantly during the period of study. One hour after a single injection of tritiated thymidine on day 4 1/2 of pregnancy the proportion of labelled cells which were granulated cells was not significantly different from the proportion of total cells which were granulated cells. However, 84 hours after the injection of thymidine the proportion of labelled cells which were granulated cells was significantly lower than the proportion of total cells which were granulated cells. Similar results were obtained from studies of the developing metrial gland of the mouse and rat. The significance of the results in relationship to an extrauterine origin for granulated metrial gland cells is considered.

Animals↗
PubMed1982

Granulated metrial gland cells in the uterus and labyrinthine placenta of inbred and outbred pregnancies in mice.

The sectional area of the labyrinthine placenta, the number of granulated metrial gland cells in the labyrinth and the number of granulated metrial gland cells in the decidua basalis + metrial gland were investigated in mice following inbred, randombred or outbred matings. The sectional area of the labyrinth in mice of the inbred LAC129 strain was greater after an outbred mating than after an inbred mating, but no such difference was detected in pregnant mice of the inbred CBA/Ca strain. However, significantly more granulated cells were found per unit area in the labyrinths of outbred pregnancies than in those of corresponding inbred pregnancies and more granulated cells were found in the decidua basalis + metrial gland of the outbred pregnancies in pregnant mice of both inbred strains. These results support the suggestion, made by previous workers, that granulated metrial gland cells are involved in the immunology of pregnancy. The number of granulated cells found in the labyrinthine placenta appears to be at its highest during the growth period of the labyrinth.

Animals↗
PubMed1981

Granulated metrial gland cells in the virgin and early pregnant mouse uterus.

A study has been made of the distribution of granulated metrial gland cells in the non-pregnant uterus, in the pre-implantation uterus and in the post-implantation interconceptual uterus of pregnant albino mice. Granulated cells were only rarely seen in the non-pregnant uterus. In the pre-implantation uterus, they were regularly seen after day 2 1/2 of pregnancy and were randomly distributed within the endometrium although there was considerable variation in numbers between animals. In interconceptual regions of the post-implantation uterus, granulated cells were found in the endometrium and, in each animal at day 5 of pregnancy, appeared to be present in smaller numbers in those regions more distant from the implantation sites. No granulated metrial gland cells were found in the interconceptual uterus at day 6 of pregnancy or later.

Animals↗
PubMed1980

Granulated metrial gland cells at implantation sites of the pregnant mouse uterus.

A study has been made of the distribution of, and synthesis of DNA by, granulated metrial gland cells at implantation sites in the pregnant mouse uterus. Granulated cells were found in small numbers randomly distributed throughout the endometrium on day 4 1/2 of pregnancy. Subsequently cells of this type were lost from the antimesometrial and lateral decidua but increased dramatically in number in the developing decidua basalis. From day 7 1/2 granulated cells populated the mesometrial triangle to form the metrial gland. A high proportion of granulated cells was found to incorporate tritiated thymidine and the distribution of such cells is described. However, no granulated cells were found to incorporate tritiated thymidine at or after day 12 of pregnancy. In addition the loss of granulated metrial gland cells from the implantation site is described and is accounted for by degeneration in situ and also by migration via vascular channels. It is suggested that this latter route could be of functional significance.

Animals↗
PubMed1979

Changes in the metrial gland of the rat uterus following ovariectomy on day 10 of pregnancy.

Rats were subjected to ovariectomy or a control operation on day 10 of pregnancy and light and electron microscope studies carried out to examine the cells of the decidua basalis and the mesometrial triangle. Degeneration of the decidua basalis was rapid but proliferation in the mesometrial triangle and differentiation of the typical granulated cells continued for some time, and resulted in the formation of a metrial gland. The earliest effect noted in the metrial gland was the appearance of inclusions in the fibroblast-like stromal cells one day after ovariectomy. During the next four days many stromal cells became packed with a variety of inclusions and it is suggested that some of these may represent phagocytosed cellular debris. Some debris appeared to be in intercellular spaces and was probably derived from granulated cells. Some granulated cells appeared to develop apparently empty vacuoles and this may be a preliminary stage in degeneration. Although granulated cells decreased to become very few in number five days after ovariectomy, the precise mechanism of their loss and the relationship of this to the hormonal environment could not be established.

Animals↗
PubMed1979

Ultrastructural changes in the rat metrial gland in the latter half of pregnancy.

The ultrastructural changes occurring in the metrial gland in the latter half of pregnancy in the rat have been studied. Typical palely stained granulated cells are present in the metrial gland up to day 20 but many granulated cells show variations in appearance which may be associated with degeneration. In some the cytoplasm is more darkly stained and such cells often have apparently empty areas of cytoplasm adjacent to the granules. From day 14 onwards many areas of the gland show cellular debris, apparently resulting from lysis of the granulated cells. However, occasionally normal granulated cells are present in blood vessels and have been observed apparently penetrating the vascular endothelium. A variety of changes was also noted in the stromal cell population. Inclusions became apparent in many of these cells; some of these consisted of lipid while others resembled granules from the typical granulated cells. Other cells with numerous inclusions appeared to be macrophages. Lysis of granulated cells in situ is compatible with suggestions that the metrial gland produces a holocrine secretion, though some normal granulated cells enter blood vessels. The stromal cells may have a phagocytic role in late pregnancy but evidence for this was inconclusive.

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↗
PubMed1978

The demonstration of cells bearing Fc receptors in the metrial gland of the pregnant rat uterus.

Cells obtained by collagenase treatment of metrial gland tissue from rats of day 12, 13, 14 and 15 of pregnancy were examined for the presence of surface membrane receptors for immunoglobulin (Fc receptors). Using an EA rosetting technique in which sheep red blood cells (SRBC) were sensitized with a rabbit anti-SRBC immunoglobulin preparation, Fc receptors were found on a proportion of the cells. The majority of the granulated metrial gland cells were not included in the rosetting cell population, suggesting that they do not possess the type of Fc receptor detected by this method. A comparison was made between results obtained when cells were counted in suspension and those obtained from cell counts on sections of fixed material. Both methods were found to yield similar results.

Animals↗
PubMed1978

The differentiation of the decidua and the distribution of metrial gland cells in the pregnant mouse uterus.

A study was made with the light microscope of the cellular changes involved in the formation of the decidua in the pregnant mouse uterus up to day 11 of pregnancy. The differentiation sequence was similar to that found by previous workers but the morphology and development of the basal zone is described in more detail. In addition, the morphology of glycogen rich cells in an area termed the lateral decidual zone is described. The distribution of granulated metrial gland cells and their precursors is described. These cells are first found in the uterine stroma before the blastocyst has implanted. Later they occur in the decidua and in the circular smooth muscle zone beneath the mesometrial triangle prior to the formation of the metrial gland. Granulated metrial gland cells are also found in the maternal blood spaces of the implantation site.

Animals↗
PubMed1978

Nonlinear modeling of multistable perception.

Multistable figures show that the stimulus-percept relation is not a single valued function. We therefore propose a tentative nonlinear model on the hypothesis that the graph of this relation is the equilibrium set of a dynamic system. For simplicity and to obtain testable predictions, we consider a system whose bifurcations are gradient-like and thus generically described by the elementary catastrophes. We motivate this general model, and then show how, in conjunction with the principle of minimal singularity, it implies cusp catastrophe geometry in a specific perceptual example. Indeed, we argue for canonical cusp geometry in this case. The model incorporates naturally certain observed features of multistable perception, such as hysteresis and bias effects. Despite being a continuum model it is naturally compatible with the subjective dichotomy of bistable perception. The model makes testable predictions which may easily be extended to other specific examples of multistable perception.

Humans↗