PubMed Health⌕ Search

Biomedical subjects

M J King

Publications and source records attributed to M J King.

At least 19 recordsLinked to original sources
PubMed1992

Novel bovine heart calmodulin-dependent protein kinase which phosphorylates a high molecular weight calmodulin-binding protein.

A novel calmodulin-dependent protein kinase has been isolated from bovine cardiac muscle by successive chromatography on DEAE-Sepharose 6B, Calmodulin-Sepharose 4B affinity and Sepharose 6B chromatography columns. The protein kinase was shown by gel filtration chromatography to have a molecular mass of 36,000 daltons. The highly purified protein kinase stoichiometrically phosphorylated the high molecular weight calmodulin-binding protein from cardiac muscle [Sharma RK (1990) J Biol Chem 265, 1152-1157] in a Ca2+/calmodulin-dependent manner. The phosphorylation resulted in the maximal incorporation of 1 mol of phosphate/mol of the high molecular weight calmodulin-binding protein. Other Ca2+/calmodulin-dependent protein kinases failed to phosphorylate the high molecular weight calmodulin-binding protein. The distinct substrate specificity of this protein kinase indicates that it is not related to the known calmodulin-dependent protein kinases and therefore constitutes a novel protein kinase.

Animals↗
PubMed1992

Demonstration of multiple forms of bovine brain myristoyl CoA:protein N-myristoyl transferase.

Four distinct N-myristoyl transferase (NMT) activity peaks, designated I, II, III, and IV, were separated from the cytosolic fraction of bovine brain by DEAE-Sepharose column chromatography. Peaks I, II, III and IV were characterised biochemically with respect to substrate specificity: with cAMP-dependent protein kinase and pp60src derived peptides, and by their apparent molecular mass. The apparent molecular mass of peaks I, II, III and IV were 190 kDa, 224 kDa, 390 kDa and 76 kDa, respectively. These results indicate that bovine brain contains multiple forms of NMT.

Acyltransferases↗
PubMed1992

Growth enhancement in transgenic Atlantic salmon by the use of an "all fish" chimeric growth hormone gene construct.

We have developed an "all fish" growth hormone (GH) chimeric gene construct by using an antifreeze protein gene (AFP) promoter from ocean pout linked to a chinook salmon GH cDNA clone. After microinjection into fertilized, nonactivated Atlantic salmon eggs via the micropyle, transgenic Atlantic salmon were generated. The presence of the transgene was detected by polymerase chain reaction (PCR) using specific oligonucleotide primers. A number of these transgenic fish showed dramatic increases in their growth rate. At one year old, the average increase of the transgenic fish was 2 to 6 fold and the largest transgenic fish was 13 times that of the average non-transgenic control.

Animals↗
PubMed1992

Effect of fentanyl on the circulatory responses to orotracheal fibreoptic intubation.

The effectiveness of fentanyl in attenuating the pressor and heart rate response to orotracheal fibreoptic intubation under general anaesthesia was assessed in 60 healthy patients undergoing elective surgery. Patients were randomly assigned to receive either fibreoptic intubation with or without fentanyl 6 micrograms.kg-1 or traditional Macintosh intubation with fentanyl 6 micrograms.kg-1. A standardised general anaesthetic was administered which included temazepam premedication, thiopentone, atracurium, oxygen, nitrous oxide and isoflurane. The pressor response to fibreoptic intubation was suppressed in those patients who received fentanyl and was similar to that seen in the Macintosh-fentanyl group of patients. The heart rate response to fibreoptic intubation was also significantly reduced in the patients who received fentanyl, but, in contrast, was still significantly greater than that in the Macintosh-fentanyl group. Fentanyl 6 micrograms.kg-1 appears to have a useful place in attenuating the cardiovascular effects of fibreoptic intubation under general anaesthesia.

Adolescent↗
PubMed1992

Point mutation in the glycophorin C gene results in the expression of the blood group antigen Dha.

The blood group Duch (Dha) antigen is located on glycophorin C (GPC). Total RNA prepared from the reticulocyte fraction of two Dh(a+) individuals were used in the synthesis of first-strand cDNA. The first-strand cDNA served as templates for the amplification of GPC-related DNA by polymerase chain reaction (PCR). The expected PCR product consisted of 412 base pairs. On sequencing the PCR-amplified DNA, a base change (cytosine----thymidine) at nucleotide 40 of the GPC cDNA was detected. Thus, the variant GPC (GPC.Dha) on Dh(a+) red cells has a substitution of leucine by phenylalanine at amino acid residue 14.

Base Sequence↗
PubMed1991

Site-specific dephosphorylation and deactivation of the human insulin receptor tyrosine kinase by particulate and soluble phosphotyrosyl protein phosphatases.

Insulin receptor tyrosine kinase activation, induced by insulin-stimulated autophosphorylation, was measured using a synthetic peptide containing residues 1142-1153 of the insulin receptor and shown to be reversed by both particulate and soluble phosphotyrosyl protein phosphatases from rat liver. Deactivation of the tyrosine kinase was highly sensitive to phosphatase action and was correlated best with disappearance of insulin receptors triphosphorylated in the tyrosine-1150 domain. Dephosphorylation of the di- and mono-phosphorylated forms of the tyrosine-1150 domain generated during dephosphorylation or of phosphorylation sites in the C-terminal or putative juxta-membrane domains occurred 3- greater than 10-fold more slowly than deactivation of the tyrosine kinase, and these phosphorylated species did not appear to appreciably (less than 20%) contribute to tyrosine kinase activation. These results indicate that the transition from the triply to the doubly phosphorylated form of the tyrosine-1150 domain acts as an important switch for deactivation of the insulin receptor tyrosine kinase during dephosphorylation. The exquisite sensitivity of this dephosphorylation/deactivation event to phosphotyrosyl protein phosphatase action, combined with the high affinities of this phosphatases for substrates and the high activities of the phosphatases in cells, suggests that the tyrosine kinase activity expressed by insulin-stimulated insulin receptors is likely to be stringently regulated.

Amino Acid Sequence↗
PubMed1991

N-myristoyl transferase assay using phosphocellulose paper binding.

N-myristoyl-CoA:protein N-myristoyl transferase is the enzyme that catalyzes the covalent transfer of myristic acid to the NH2-terminal glycine residue of a protein, or peptide, substrate. We have established a new, rapid, reliable, and inexpensive myristoyl-CoA:protein N-myristoyl transferase assay. This N-myristoyl transferase assay is based on the binding of the [3H]myristoylated peptide to a P81 phosphocellulose paper matrix and is more convenient for assaying multiple samples than existing procedures. Two peptides, derived from the N-terminal sequences of the type II catalytic subunit of cAMP-dependent protein kinase and pp60src, were used as substrates. A survey of rat and bovine tissue extracts demonstrated that in both cases brain contained the highest NMT activity (i.e., brain greater than spleen greater than heart greater than liver). Under the assay conditions used, the rate of myristoylation was linear for 10 min and with up to 4.0 mg/ml of brain extract.

Acyltransferases↗
PubMed1991

Immunochemical studies on the differential binding properties of two monoclonal antibodies reacting with Tn red cells.

Two monoclonal antibodies (MoAbs), BRIC 66 (IgM) and BRIC 111 (IgG1), were produced by immunizing mice with ovarian cyst blood group A1 glycoprotein and Tn red cells (RBCs), respectively. Their specificities were determined by inhibitions using Tn sialoglycoproteins (SGPs), mucins (armadillo [ASG] and ovine [OSG] submaxillary glycoproteins), and monosaccharides. BRIC 66 agglutinated both Tn and group A RBCs and reacted immunohistochemically with both the vascular endothelium and tumor cells from a group A adenocarcinoma, BRIC 66 was inhibited by N-acetylgalactosamine (GalNAc), Tn SGPs, and mucins on both hemagglutination inhibition tests and radioimmunoassay. BRIC 111 agglutinated Tn RBCs only, and it specifically stained tumor cells from a group O patient's breast carcinoma and a group A patient's adenocarcinoma. In hemagglutination inhibition tests, BRIC 111 was readily inhibited by Tn SGPs, only partially inhibited by GalNAc, and not inhibited by mucins. In a sensitive radioimmunoassay, BRIC 111 was inhibitable by GalNAc. Tn SGP was 2000-fold more effective as an inhibitor than the mucins (ASG and desialized OSG), which contain a high content of terminal alpha-GalNAc-O-serine (threonine) residues. It is postulated that BRIC 66 is specific for terminal alpha-GalNAc units in carbohydrate chains. The exclusive reaction of BRIC 111 with Tn SGP indicates a combining site larger than GalNAc alpha-1, which probably includes amino acid residues in juxtaposition to GalNAc in Tn SGP. In view of its specific agglutination of Tn RBCs, BRIC 111 is a useful reagent for the examination of polyagglutinable RBCs.

ABO Blood-Group System↗
PubMed1991

Evaluation of bovine serum albumin preparations and Ficoll addition in capillary tube hemagglutination.

Eighteen commercial bovine serum albumin (BSA) preparations were evaluated for their efficacy in hemagglutination enhancement by the capillary tube method. Their physicochemical variables (pH, conductivity, free fatty acids, total protein, and polymer content) were quantified. The results showed that a BSA preparation which consistently performed well in hemagglutination enhancement contained some albumin polymer and had a low free fatty acid content. We also found that the addition of Ficoll (final concentration of 1.24%) could convert BSA preparations producing mediocre hemagglutination enhancement into good enhancers, provided that these preparations did not have high free fatty acid content. Hence, the addition of Ficoll can obviate the requirement for selecting a polymer-enhanced albumin for use in capillary tube tests.

Animals↗
PubMed1990

Dephosphorylation of insulin-receptor autophosphorylation sites by particulate and soluble phosphotyrosyl-protein phosphatases.

Insulin stimulates autophosphorylation of the insulin receptor on multiple tyrosines in three domains: tyrosines 1316 and 1322 in the C-terminal tail, 1146, 1150 and 1151 in the tyrosine-1150 domain, and possibly 953, 960 or 972 in the juxtamembrane domain. In the present work the sequence of dephosphorylation of the various autophosphorylation sites by particulate and cytosolic preparations of phosphotyrosyl-protein phosphatase from rat liver was studied with autophosphorylated human placental insulin receptor as substrate. Both phosphatase preparations elicited a broadly similar pattern of dephosphorylation. The tyrosine-1150 domain in triphosphorylated form was found to be exquisitely sensitive to dephosphorylation, and was dephosphorylated 3-10-fold faster than the di- and monophosphorylated forms of the tyrosine-1150 domain or phosphorylation sites in other domains. The major route for dephosphorylation of the triphosphorylated tyrosine-1150 domain involved dephosphorylation of one of the phosphotyrosyl pair, 1150/1151, followed by phosphotyrosyl 1146 to generate a species monophosphorylated mainly (greater than 80%) at tyrosine 1150 or 1151. Insulin receptors monophosphorylated in the tyrosine-1150 domain disappeared slowly, and overall the other domains were completely dephosphorylated faster than the tyrosine-1150 domain. Dephosphorylation of the diphosphorylated C-terminal domain yielded insulin receptor in which the domain was singly phosphorylated at tyrosine 1322. Triphosphorylation of the insulin receptor in the tyrosine-1150 domain appears important in activating the receptor tyrosine kinase to phosphorylate other proteins. The extreme sensitivity of the triphosphorylated form of the tyrosine-1150 domain to dephosphorylation may thus be important in terminating or regulating insulin-receptor tyrosine kinase action and insulin signalling.

Animals↗
PubMed1990

Monoamine and amino acid content in brain regions of Brattleboro rats.

Monoamine and amino acid content were measured in brain regions from 12 week old male, homozygous Brattleboro (DI, n = 12) and Long-Evans control (LE, n = 12) rats. Norepinephrine (NE) content was significantly elevated (16-25%) in the spinal cord, pons-medulla and anterior hypothalamus of DI rats when compared to LE controls. NE content of the neurointermediate lobe of pituitary in DI rats was almost twice that of LE controls. Serotonin content was also significantly elevated in the spinal cord, pons-medulla, anterior hypothalamus and forebrain of DI rats relative to the LE controls. Taurine content in DI rats was increased (31-42%) above that of LE rats in the anterior hypothalamus, striatum and forebrain. Glutamine content was also greater in DI rats than LE in the spinal cord, pons-medulla, anterior hypothalamus, striatum, hippocampus and forebrain. The changes in monoamine and amino acid content were discussed in relation to the cardiovascular and osmoregulatory deficits that are present in DI rats due to arginine vasopressin (AVP) deficiency. The possible role of AVP in modulating NE turnover was also discussed. The increase in brain TAU content in DI rats may be a physiological response to hypernatremia.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1990

A study of HLA (Bg) on red cells and platelets by immunoblotting with monoclonal antibodies.

HLA class I antigens (Bg) on red cells (RBCs) are expressed by some normal donors and by many patients with systemic lupus erythematosus (SLE). To identify the membrane components previously detected by hemagglutination with HLA class I-specific monoclonal antibodies (MoAbs), RBC membrane preparations were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotted with the HLA class I MoAbs. Two components were obtained that reacted with the MoAbs: a heavy chain of 45 kDa and a light chain termed beta2-microglobulin (beta2-M) of 11 kDa. The effect of chloroquine and acid elution in stripping HLA antigens is shown to be due to the removal of beta2-M, as only that component was detected in eluates from reactive RBCs. Neither antibody elution method affected the heavy chain expression assessed by immunoblotting. It is concluded that HLA class I antigens on RBCs are integral membrane components of the type normally found and wisely distributed on many nucleated cells. Platelets, which have stronger HLA class I antigen expression, were also studied, and their membrane preparations yielded heavy chain and beta2-M molecules; the effect of chloroquine treatment was harder to assess than that of acid elution, owing to the sensitivity with which both components are detected in immunoblotting. In eluates obtained from acid treatment only beta2-M is detected.

Antibodies, Monoclonal↗
PubMed1990

Epidural fentanyl and 0.5% bupivacaine for elective caesarean section.

Either 100 micrograms fentanyl or 2 ml saline was added to 0.5% bupivacaine administered epidurally for elective Caesarean section in 30 patients, in a double-blind randomised study. Bupivacaine 0.5% was administered until a complete sensory block was established extending to the 4th thoracic dermatome. One of the patients who received epidural fentanyl required intravenous alfentanil and Entonox and another, Entonox only briefly during surgery, compared with seven in the control group who required intravenous alfentanil and Entonox and one who required Entonox only. Postoperative analgesia was of longer duration in those who received epidural fentanyl (p less than 0.01). There were no deleterious effects on neonatal or maternal outcome.

Adult↗
PubMed1989

Regulation of antifreeze protein production in winter flounder: a unique function for growth hormone.

Salmon pituitary extract and the protein fraction unabsorbed on concanavalin A-Sepharose, the carbohydrate-poor fraction, depressed plasma levels of antifreeze proteins (AFP) when the pituitary fractions were administered to flounder in late fall or winter. The active pituitary protein occurred in the fraction with a mean molecular weight of 25,000. The two major isohormones of growth hormone (GH) were the only biologically active proteins identified from the pituitary. Hypophysectomized flounder synthesize AFP in the spring and the two isohormones of GH suppress the synthesis. The fraction of flounder pituitaries containing putative GH depressed flounder plasma levels of AFP in late fall.

Acclimatization↗
PubMed1989

An application of immunoblotting in the classification of the Miltenberger series of blood group antigens.

A simple scheme is described for the classification of Miltenberger cell classes I to VI, which is consistent with the serologic definition of the determinants. The scheme is based on the reaction patterns obtained by immunoblotting the normal and abnormal sialoglycoproteins (SGPs) found in these cells with several murine monoclonal antibodies that recognize different epitopes on alpha-SGP (Glycophorin A). The abnormal alpha found in MiI and MiII cells is easily identified with these antibodies, as is the abnormal alpha-delta SGP found in MiV cells. Certain alpha-SGP antibodies recognize epitopes on the abnormal SGPs found in MiIII, MiIV, and MiVI cells, although the mode of inheritance of these abnormal SGPs suggests that they are related to delta-SGP (Glycophorin B). Antibody R18 reacts with the abnormal SGP of MiIII cells but not that of MiIV or MiVI cells, whereas antibody BRIC 119 reacts with MiIII, MiIV, and MiVI cells. None of the abnormal components in these three cell classes react with antibody R10 or with an antibody (BRIC 163) that recognizes an epitope on the cytoplasmic portion of alpha-SGP. The immunostaining of membranes from persons heterozygous for the MiVII and MiVIII classes revealed patterns identical to those of normal red cell membranes. However, antibody R18 did not react with any of the SGP components of homozygous MiVII cells.

Antibodies, Monoclonal↗
PubMed1989

Effects of halothane on somatosensory evoked potentials recorded in the extradural space.

We studied the effects of supplementing anaesthesia with halothane (up to 1.5%, inspired) on the somatosensory evoked potential recorded in the extradural space of six patients before corrective surgery for idiopathic adolescent scoliosis. A further six patients in whom anaesthesia was supplemented with thiopentone acted as a control group. Halothane 1.5% resulted in a significant decrease in overall amplitude (P less than 0.05) from the left leg only. Halothane had no significant effect on overall amplitude, first peak amplitude, second peak amplitude and first peak latency. We conclude that halothane is unlikely to alter the interpretation of somatosensory evoked potentials recorded extradurally during scoliosis surgery. A possible unilateral effect of halothane on the concave side in idiopathic adolescent scoliosis needs further investigation.

Adolescent↗
PubMed1989

House dust mites in naval ships, military barracks, and homes in the Hampton Roads area of Virginia.

This survey was undertaken to determine the possible exposure of military personnel to house dust mites in ships, barracks, and homes in the Hampton Roads area of Virginia. During the period from April 1, 1982 through August 31, 1983, 524 dust samples were collected with vacuum cleaners. Mites were extracted from aliquots of dust, counted, and identified as to species and life stage. Dermatophagoides pterynssinus (European house dust mite) was more common in private homes, while Dermatophagoides farinae (North American house dust mite) was more common on ships. Berthing compartments had the highest density of mites of areas sampled aboard ships. There appears to be a trend between the density of personnel and mites. Ships had a smaller percentage of mite-infested samples than houses.

Animals↗