Search PubMed⌕ Search

Biomedical subjects

B Morris

Publications and source records attributed to B Morris.

At least 73 records · Page 4Linked to original sources
PubMed1986

Localisation of [3H] clonidine binding in rat neurohypophysis by means of electron-microscopic autoradiography.

Electron-microscopic autoradiography of rat neurohypophyses treated with [3H] clonidine, an alpha 2-agonist, showed that binding apparently occurred preferentially at the neurosecretory endings and blood vessels rather than on the pituicytes. Since it is known that clonidine has a high affinity for plasma proteins, the distribution over the neurosecretory nerve endings would suggest the existence of presynaptic alpha 2-binding sites on neurosecretory neurones, which could indicate a regulatory function for catecholamines in neurohypophysial hormone release.

Animals↗
PubMed1986

Herbalism and divination in southern Malawi.

Although contemporary anthropological studies of African medical systems have indicated their pluralistic and complex nature, many studies still suggest a stark contrast between folk and cosmopolitan medicine, implying that ethnomedicine is primarily concerned with mystical causation. The present paper outlines ethnomedical practices in southern Malawi, stressing the distinctiveness of herbalists and diviners, and the important role of herbal remedies in the empirical treatment of all illnesses.

Adult↗
PubMed1986

The role of gut-associated lymphoid tissues in the generation of immunoglobulin-bearing lymphocytes in sheep.

Experiments were designed to examine the relative contributions of Peyer's patches and mesenteric lymph nodes to the population of circulating immunoglobulin-bearing lymphocytes in sheep. The ileum, with more than 90% of the total Peyer's patches, the mesenteric lymph nodes, or both, were removed from lambs at different stages of development and the composition of the cell populations in lymph from different sources and in the blood was examined. Lambs which had had the ileum removed before or within a few days of birth were deficient in small lymphocytes bearing membrane immunoglobulin. This deficit remained for at least the first year of the animals' lives. Neither the removal of mesenteric lymph nodes nor removal of the ileum had any statistically significant effect on the total output of cells or on the population of IgA-producing cells in lymph draining from the gut.

Aging↗
PubMed1986

Release of i-r metenkephalin from rat amygdala slices in vitro.

Release of immuno-reactive metenkephalin has been demonstrated from slices of rat amygdala in vitro. This release was calcium dependent and the amount released was related to the concentration of potassium ions in the releasing stimulus. The effect of drugs such as clonidine, an alpha 2 adrenoceptor agonist, and idazoxan, an antagonist, on this release was measured. Neither drug had a significant effect on the amount of ir-metenkephalin released. Thus although release of noradrenaline can be affected by opioids it seems that release of endogenous opioids is not affected by drugs which interact with noradrenaline.

Adrenergic beta-Antagonists↗
PubMed1985

The lymph-borne response of foetal lamb lymph nodes to challenge with Brucella abortus in utero.

The cannulated prescapular lymph node of the foetal lamb was challenged with killed Brucella abortus. Usually, both efferent prescapular ducts were cannulated and one node left as a control. Nodes were given primary or secondary challenges with doses of 10(9) - 2 X 10(10) brucella organisms and the lymph-borne response of the nodes followed. The foetal lymph node produced a vigorous cellular response to the injected brucella, restricted to the challenged side. The total cell output and, more strikingly, large cell output increased to reach a peak value 4-5 days after challenge. This cellular response was seemingly dose-dependent. The output of antibody after a primary challenge was delayed considerably and could not be detected in the lymph until well after the cellular response had subsided. The concentrations of antibody produced were quite low and almost all mercaptoethanol-sensitive. With secondary challenges the output of antibody occurred much more quickly, in phase with the cellular response, and appreciable amounts of mercaptoethanol-resistant antibody were produced. Under exceptional circumstances, high titre, highly specific anti-brucella antibody has been produced in foetal lymph. The foetal lymph node provides a powerful tool for further studies of the ontogeny of the immune response, and might help elucidate the failure of newborn animals to respond to some important bacterial antigens.

Animals↗
PubMed1985

The long-term collection of lymph from single lymph nodes of foetal lambs in utero.

Surgical techniques are described for the long-term collection of lymph from both prescapular efferent lymph ducts of foetal lambs in utero. Lymph ducts in foetal lambs 95 to 136 days post-conception were cannulated with a high rate of success. Lymph flow from the cannulas was not compromised by deliberate primary or secondary challenge of the lymph nodes with a wide variety of antigens, and often continued for long periods after the lambs were born naturally. The techniques allow cellular and humoral lymph-borne immune responses of foetal lambs to authentic primary antigenic challenge to be studied in utero, uncomplicated by any previous experience of antigens. Loss of lymphocytes from the cannulated ducts depleted the numbers of cells in the lymph, but lymph protein concentrations were unaffected by lymph drainage.

Animals↗
PubMed1985

Child abuse manifested as factitious apnea.

A 6-week-old male infant was admitted for near-miss SIDS documented in the hospital. The episodes were subsequently found to be factitious apnea that occurred as a result of the father suffocating the child. Apnea monitoring did not prevent, and in fact perpetrated the illusion of SIDS in this infant.

Airway Obstruction↗
PubMed1984

Multiple forms of hepatic cytochrome P-450. Purification, characterisation and comparison of a novel clofibrate-induced isozyme with other major forms of cytochrome P-450.

In the present studies, a novel form of highly purified cytochrome P-450 (cytochrome P-452) isolated from the hepatic microsomes of clofibrate-pretreated rats has been compared to the major isozymes isolated from the hepatic microsomes of rats pretreated with phenobarbital (cytochrome P-450) and 2-naphthoflavone (cytochrome P-447) using a number of biochemical criteria. The results show that these three isozymes exhibit marked structural differences from each other as judged by a complete lack of immunochemical cross-reactivity between the isozymes and the heterologous rabbit serum antibodies using Ouchterlony double diffusion, and non-identity between the limited proteolytic digestion maps of the three isozymes obtained in the presence of chymotrypsin, papain and Staphylococcus aureus V8 proteases. Furthermore, the three isozymes exhibited clear differences in their monomeric molecular weights determined on calibrated sodium dodecyl sulphate/polyacrylamide gel electrophoresis in gels of varying acrylamide concentration. Substantial differences were also observed in the substrate specificities of the isozymes, which were reflected in differences in the turnover rates and positional selectivities of the hemoproteins for some model substrates. In addition, the isozymes differed in their substrate binding affinities and their ability to interact with purified hepatic microsomal cytochrome b5, as judged using difference spectrophotometry. Finally, subtle differences were detected in the ultraviolet visible absorbance spectra of the hemoproteins in the ferric, ferrous, and carbonmonoxyferrous states. Taken collectively, the above data provides compelling evidence that fundamental differences exist between these cytochrome P-450 isozymes, further establishing the uniqueness of the major form of cytochrome P-450 induced by clofibrate pretreatment.

Animals↗
PubMed1984

The effect of antigen on the development of Peyer's patches in sheep.

The proposition that the development of Peyer's patches (PP) is influenced by antigenic stimulation has been examined in sheep. Terminal lengths of ileum containing about half of the ileocecal PP were isolated from the intestinal tracts of fetal lambs during the last month before birth. Antigen was injected into some of these segments and the subsequent development of the PP studied before and after birth. The injection of either killed B. abortus, ferritin or maternal colostrum into the lumens of the isolated ileal segments did not cause premature growth of the PP follicles, nor did it effect the content of lymphoblasts in them. In contrast, the injection of these antigens into the isolated segments caused the development of germinal centers and plasma cells in the regional mesenteric lymph nodes. Plasma cells also appeared in the lamina propria along the intestinal tract in response to these antigens. These results provided experimental evidence that lymphopoiesis in the follicles of the PP of fetal lambs is not dependent on antigen. The PP in ileal segments that were not injected with antigen and had no contact with antigen subsequently grew at the normal rate before and for the first 2 weeks after birth; after this the growth of the follicles became significantly slower than normal. The follicles in these isolated ileal segments had almost completely disappeared by 3-4 months of age, whereas the follicles in the normal functional ileum did not undergo involution until around 15 months of age. The premature involution in the PP in the isolated segments was prevented by reconnecting the segment to the functional intestinal tract before 3 months of age.

Animals↗
PubMed1984

Autoradiographic demonstration of alpha 2 adrenoceptors in the bovine neurohypophysis.

Autoradiography of sections from neurohypophyses treated with tritiated clonidine has shown specific binding to alpha 2-adrenoceptor sites in the neurohypophysis but not in the intermediate lobe. Other studies have shown that alpha 2 agonists such as clonidine can cause a fall in circulating antidiuretic hormone; it is therefore possible to speculate that this action could be a direct one on the neurohypophysis since the appropriate binding sites have been shown to exist.

Animals↗
PubMed1984

Binding of [3H]clonidine to membranes from cow neurohypophysis and cerebral cortex of the rat.

The binding of [3H]clonidine to membranes prepared from rat cerebral cortex and cow neurohypophysis was compared. Both tissues showed a high affinity site and a low affinity site when examined using a variety of techniques. The binding data, together with displacement studies using a variety of alpha 2-adrenoceptor agonists and antagonists, indicated that the binding activity of clonidine in the two tissues was very similar, however when the putative sigma opiate compound SKF 10,047 was examined it was found to have only a weak activity in displacing clonidine on the cortical membranes but a much stronger activity on the neurohypophysial membranes, other opiates showed little activity on binding of clonidine in either tissue. It is proposed that the binding of clonidine to neurohypophysial membranes may explain in part the various reports of suppression by clonidine of release of hormones from the neurohypophysis and that the effects of SKF 10,047 may be similarly associated with the reports of diuresis induced by phencyclidine.

Adrenergic alpha-Agonists↗