PubMed Health⌕ Search

Biomedical subjects

I Morgan

Publications and source records attributed to I Morgan.

33 records · Page 2Linked to original sources
PubMed1994

INTRACELLULAR ION CONCENTRATIONS IN BRANCHIAL EPITHELIAL CELLS OF BROWN TROUT (SALMO TRUTTA L.) DETERMINED BY X-RAY MICROANALYSIS

The intracellular concentrations of sodium, chloride, phosphorus and potassium under normal conditions in pavement epithelial (PE) cells of brown trout (Salmo trutta) gill were 66, 51, 87 and 88 mmol l-1 respectively. The concentrations of these elements under identical conditions in mitochondria-rich (MR) cells were not significantly different, except for that of chlorine, which was lower in MR cells (40 mmol l-1). The concentration of sodium in the PE cells decreased slightly after exposure of the fish to low external [Na+] (25 µmol l-1) for 7 days but increased greatly within 5 min of subsequent exposure to 1 mmol l-1 external Na+. These changes in external [Na+] had no significant effect on MR cells. Exposure of fish to low [Cl-] (25 µmol l-1) had no effect on PE or MR cells, but on exposure to 1 mmol l-1 Cl- the concentrations of chlorine, phosphorus and potassium in both types of cells increased, whilst the intracellular sodium concentration decreased only in MR cells. The PE cells were little affected by exposure of the fish to the carbonic anhydrase inhibitor acetazolamide. In contrast, 0.5 mmol l-1 external acetazolamide caused a significant decrease in intracellular phosphorus, chlorine and potassium concentrations in MR cells. This suggests that the PE cells are the sites of sodium uptake in the gills of the brown trout and that chloride uptake occurs via the MR cells. These results are discussed with respect to the sites and possible mechanisms of ionic exchange in freshwater vertebrates.

Journal Article↗
PubMed1990

The genetics of jun.

Mutational analyses of Jun show that the leucine zipper mediates dimerization with other Jun molecules or with the Fos protein and determines the three-dimensional orientation of the adjacent basic region, facilitating interaction with DNA. The basic region of Jun is the DNA contact surface. Substitution of certain basic residues in this region leads to loss of DNA binding. Some basic region mutants also act as transdominant lethals: they are able to tie up wild type protein in inactive complexes. The definition of transactivator domains with deletion mutants of Jun appears to depend on the assay for transcriptional activation. CAT assays suggest multiple transactivator regions in the N-terminal third of Jun, while in vitro transcription assays detect a negative regulator of transcription in this region. Another transactivator domain appears to be located close to the basic region in both c-Jun and JunD. The genetics of Jun supports a hierarchical order of Jun functions in which dimerization is a prerequisite for both DNA binding and transcriptional activation, and DNA binding is needed for transcriptional activation.

Amino Acid Sequence↗
PubMed1989

Characterization of paramyxoviruses isolated from penguins in Antarctica and sub-Antarctica during 1976-1979.

Nine paramyxovirus isolates obtained from penguins were tested for antigenic relationships amongst themselves and to other avian paramyxoviruses. One of the isolates was shown to be a lentogenic Newcastle disease virus (NDV), i.e., of PMV-1 serotype. By serological tests and analysis of structural polypeptides the other penguin isolates could be placed into three groups. No relationship with other avian paramyxoviruses could be determined except that six of the penguin viruses, representing two of the groups, showed reaction with a monoclonal antibody raised against NDV Ulster 2C and three of the isolates, representing one of the penguin groups, also reacted with another PMV-1 directed monoclonal antibody.

Animals↗
PubMed1982

Insulin clearance by perfused rat lung.

The clearance of insulin has been demonstrated in the perfused in situ rat lung. Porcine insulin added to the perfusion medium at 50 microunits/l was cleared at 6.3 U/h in lungs from fed animals, 6.1 U/h in fasted animals and 15.7 U/h in diabetic rat lungs. At a higher concentration of insulin (500 microunits/l) increased clearance was observed in lungs from both fed, fasted and diabetic animals, 33.0, 36.0 and 56.5 U/h respectively. It is suggested that the clearance of insulin by the lung is dependent on metabolic state of the animal.

Animal Nutritional Physiological Phenomena↗
PubMed1978

Metronidazole treatment in pregnancy.

Vaginal trichomoniasis was treated with standard courses of oral metronidazole in 597 pregnant women. In 283 other pregnant women, the infection remained untreated. The incidences of low-birth-weight infants, stillbirths and congenital abnormalities were not affected by metronidazole treatment of trichomoniasis in pregnancy.

Abnormalities, Drug-Induced↗
PubMed1977

The effect of insulin on lung metabolism in the rat.

A new model has been established for the perfused in situ rat lung. During perfusion with glucose at 4 mmol/l, physiological concentrations of insulin (50 mu/l) caused an initial 1.5 fold increase in lactate production; the increase being sustained at 30% for the 4 h of perfusion. The observation that the lung responds to physiological concentrations of insulin could have important implications with respect to whole body carbohydrate metabolism.

Animals↗
PubMed1976

Distribution of protein kinase activities in subcellular fractions of rat brain.

The subcellular distribution of histone and phosvitin kinase activities in brain has been studied and the ability of the various fractions to catalyse the phosphorylation of their endogenous proteins (intrinsic protein kinase activity) also examined. Synaptosome membrane fragments have little or no histone or phosvitin kinase activity but contain the highest concentration of cyclic AMP-stimulated intrinsic protein kinase activity. Homogenisation of the membrane fragments in Triton X-100 increased the histone kinase activity but on centrifugation it was all recovered in the supernatant, while the insoluble material contained all the intrinsic protein kinase activity. These results indicate that the intrinsic protein kinase activity of cerebral membrane fragments is due to the presence of a kinase enzyme which is specific to certain membrane proteins. The intrinsic protein kinase activity of synaptosome membrane fragments is a rather slow reaction which takes several minutes to saturate all the acceptor proteins.

Animals↗