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Biomedical subjects

B Morris

Publications and source records attributed to B Morris.

At least 109 records · Page 6Linked to original sources
PubMed1980

The effect of exogenous steroids and steroid inhibitors on IgG transmissions in young rats.

The transmission of labelled IgG by the proximal small intestine was assessed in 16- and 18-day-old rats. Closure had commenced by 18 days and in some animals was well advanced by this age. The injection of large doses of cortisone acetate, hydrocortisone sodium succinate, deoxycorticosterone acetate and corticosterone induced precocious closure of the small intestine by 16 days; and all but the latter steroid also induced precocious cell replacement in the ileum. Maternal deprivation for about 18 h daily led to closure of the proximal small intestine but did not induce precocious replacement in the ileum. The injection of metopirone, aminoglutethimide and ACTH resulted in partial closure of the proximal small intestine but did not induce precocious cell replacement in the ileum. Maternal deprivation for about 8 h daily produced a similar result.

Adrenocorticotropic Hormone↗
PubMed1980

The physical and functional heterogeneity of circulating lymphocyte populations.

There is a considerable heterogeneity amongst populations of both fixed and circulating lymphocytes other than that determined by the organs from which these cells originate. The functional differences with which these cells are endowed during their primary differentiation are further modified by the changing environments they encounter during their life and by reassortitive processes occurring during their migration. The range of inductive and modulating stimuli applied to the free-floating and fixed lymphoid cell populations in different parts of the lymphatic apparatus is changing continually and this leads to patterns of cell differentiation which persist for variable periods of time. The experience of a variety of environmental interactions gives the lymphocyte a range of reactive options which are denied to those cells held in fixed relationships with other cells. As a consquence there is no predictable equivalence in the morphological or functional attributes of different lymphocyte populations present in different parts of the lymphatic system.

Animals↗
PubMed1978

Humoral immune responses in foetal sheep.

A total of fifty-two foetal sheep between 49 and 126 days gestation were injected with polymeric and monomeric flagellin, dinitrophenylated monomeric flagellin, chicken red blood cells, ovalbumin, ferritin, chicken gamma-globulin and the somatic antigens of Salmonella typhimurium in a variety of combinations. Immune responses were followed in these animals by taking serial blood samples from them through indwelling vascular cannulae and measuring the circulating titres of antibody. Of the antigens tested, ferritin induced immune responses in the youngest foetuses. A short time later in gestation, the majority of foetuses responded to chicken red blood cells, polymeric flagellin, monomeric flagellin and dinitrophenylated monomeric flagellin. Only older foetuses responded regularly to chicken gamma-globulin and ovalbumin. However, antibodies to all these antigens were first detected over the relatively short period of development between 64 and 82 days gestation and this made it difficult to define any precise order in the development of immune responsiveness. Of the antigens tested only the somatic antigens of S. typhimurium failed to induce a primary antibody response during foetal life. The character and magnitude of the antibody responses in foetuses changed throughout in utero development. Both the total amount of antibody produced and the duration of the response increased with foetal age. Foetuses younger than 87 days gestation did not synthesize 2-mercaptoethanol resistant antibodies or IgG1 immunoglobulin to any of the antigens tested, whereas most foetuses older than this regularly did so.

Animals↗
PubMed1977

The traffic of mononuclear phagocytes through renal allografts in sheep.

Five to ten per cent of the cells in lymph draining renal allografts in sheep have the morphology of mononuclear phagocytes (MNP). These cells have been examined by light and electron microscopy and their functional characteristics investigated. The vast majority of MNP were of recipient origin. Their traffic increased from about 10(6)/hr immediately after grafting to between 2 and 4 X 10(7)/hr just prior to rejection. During the 1st 2 to 3 days, the majority of MNP had the morphology of monocytes, but the proportion of mature macrophages increased steadily to 30%. During the later stages, many of these large macrophages showed features of activation in terms of their spreading and phagocytic capacities. No NDA synthesis was observed in MNP until the latest stages, when a small proportion (less than 1%) of MNP labelled in vitro. Short-term cultures of lymph cells from kidneys undergoing rejection gave rise to numerous giant cells. It is suggested that there is continual traffic of MNP through the grafted kidney and that a proportion of MNP differentiate within the kidney and show features of activation.

Animals↗
PubMed1977

Fractionation studies on the absorption of labelled immunoglobulin G by the gut of young rats.

1. Centrifugation in density gradients was used to study the fragments produced during intraluminal and intracellular digestion, after the injection of 125I-labelled immunoglobulin G (IgG) into different regions of the small intestine of 14 to 15-day-old (pre-closure) and 24-day-old (post-closure/ rats. 2. After injection into the proximal small intestine and into the ileum of pre-closure animals, the bulk of the radioactivity recorded for gut washes and gut homogenates was located at 4S-7S. The serum from animals which had received injections into the proximal small intestine had high radioactivity and one peak at 7S; the serum from animals which had received injections into the ileum had low radioactivity and no activity in the 7S region. 3. After injection into the proximal small intestine of post-closure animals, the bulk of the radioactivity recorded for gut wash samples was located at 3-5S--5S. Gut homogenates had peak activity at 2-5S--4S. Thus large molecular weight products can be absorbed by the proximal enterocytes of post-closure rats and degraded. The sera of these animals had low radioactivity. 4. After injection into the distal small intestine of post-closure animals, the bulk of the radioactivity recorded for gut wash and gut homogenate samples was located at 4S-7S and in this respect the radioactivity plots resembled those for (2) above. Serum radioactivity was low. 5. The effect of precipitation with trichloroacetic acid and incubation with specific antiserum upon the radioactivity of gut washes, gut homogenates and serum samples was recorded. 6. The relevance of these findings to studies on the transmission of protein by the rat small intestine is discussed.

Animals↗
PubMed1977

The digestion and transmission of labelled immunoglobulin G by enterocytes of the proximal distal regions of the small intestine of young rats.

Density gradient centrifugation of samples prepared from proximal gut homogenates after intra-lumenal injection of 125I-labelled IgG, was used to prepare batches of IgG fragments according to sedimentation coefficients. 2. Ultrafiltration was employed to partition the radioactivity in the vascular compartments, viscera and carcasses of rats aged 14-15 days, 2 hr after the injection of standard doses of labelled IgG into the proximal and distal regions of the small intestine. 3. Radioactive samples prepared by these methods were re-introduced into young rats by intra-cardiac injection, and the rate at which they were removed from the vascular compartment was assessed. 4. Proximal enterocytes transmitted about 39% of the IgG which had been removed from the intestine in intact form. Most of this was retained in the vascular compartment; they degraded up to about 57% of the total removed into fragments less than 1000 mol. wt. and about 4% into intermediate sized fragments. 5. Distal enterocytes degraded almost 90% of the IgG processed into fragments less than 1000 mol. wt., about 8% as fragments greater than 100,000 mol. wt. 6. Fragments, of all sizes, were cleared rapidly from the circulation into the viscera and carcass. 7. The relevance of these results to protein transmission and digestion by the rat small intestine is discussed.

Animals↗
PubMed1977

Cartilage hair hypoplasia.

Six cases of cartilage hair hypoplasia from five kindreds are described. They demonstrate variation in the expression of clinical features such as sparsity of hair, hair calibre, radiological changes, short stature and the extent of the disproportion between sitting height and stature.

Age Factors↗
PubMed1977

Cells and immunoglobulins in lymph.

Studies of the free-floating lymphocytes and of the immunoglobulins in lymph collected over long periods of time from ducts draining individual tissues of the body as well as from the thoracic duct of the fetus in utero have been reviewed. The findings show that stimuli within the internal milieu act on different classes of lymphocytes to alter their migration pattern, morphology, metabolic activity, and range of immunological potentialities. As the lymphoid cells migrate between the blood, tissue fluid, and lymph, a continual process of reassortment occurs leading to the establishment of heterogeneous lymphoid cell populations in different regions of the lymphatic apparatus. It seems that the biological activities of these cells are not decided only in terms of a thymus or a bone-marrow origin. The immunoglobulins, like other proteins in lymph, are mainly derived by filtration from the circulating plasma. Some of the immunoglobulins and specific antibodies are synthesized, however, by lymphoid cells and secreted directly into the lymph.

Antibody-Producing Cells↗