Search PubMed⌕ Search

Biomedical subjects

J M Murray

Publications and source records attributed to J M Murray.

At least 127 records · Page 7Linked to original sources
PubMed1983

Chemical and antigenic characterization of the carbohydrate side chains of an Asian (N2) influenza virus neuraminidase.

The Pronase-released neuraminidase heads from the Asian influenza virus A/Tokyo/3/67 contain four oligosaccharide units attached at asparagine residues 86, 146, 200, and 234. Chemical analysis of the isolated tryptic, chymotryptic, or thermolytic glycopeptides shows that the oligosaccharide side chains attached at residues 86 and 200 are essentially of the oligomannoside (simple or Type II) variety containing two residues of N-acetylglucosamine, five residues of mannose, and less than molar ratios of galactose and fucose. The carbohydrate side chains attached at residues 146 and 234 are of the N-acetyllactosamine (complex or Type I) type and contain N-acetylglucosamine, mannose, galactose, and fucose. The complex oligosaccharide unit at residue 146 is unusual in that it also contains N-acetylgalactosamine, a sugar residue rarely found in N-glycosidically linked carbohydrates. Antigenic analysis of these four isolated glycopeptides showed that only the N-acetyllactosamine oligosaccharide unit at asparagine residue 146 was capable of binding to antibodies raised against uninfected chick chorioallantoic membranes and is hence antigenically related to chick embryo host antigen.

Amino Sugars↗
PubMed1983

Genetic linkage relationship between the Xg blood group system and two X chromosome DNA polymorphisms in families with Duchenne and Becker muscular dystrophy.

The existence of linkage has been investigated between the Xg blood group system, two DNA restriction fragment length polymorphisms (RFLPs) located on the short arm of the X chromosome, Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). No linkage was found between the Xg locus and the more proximal RFLP (L 1.28); close linkage between Xg and the more distal RFLP (lambda RC8) was also excluded. Both RFLPs show linkage with DMD but are not closely linked with each other. Analyses of 11 families with DMD and ten with BMD, informative for the Xg blood group, reinforce the conclusions of others that there is no measurable linkage between the loci for Xg and for the X-linked forms of muscular dystrophy.

Blood Group Antigens↗
PubMed1983

Absence of genetic heterogeneity in Duchenne muscular dystrophy shown by a linkage study using two cloned DNA sequences.

A linkage study using two different restriction fragment length polymorphisms (RFLPs) identified with cloned DNA sequences has failed to provide evidence for genetic heterogeneity in Duchenne muscular dystrophy (DMD) when tested against intelligence quotient (IQ). Analysis of data for age of confinement to a wheelchair against IQ gave no evidence for heterogeneity. These results are of a practical as well as theoretical significance, since the existence of multiple loci causing DMD would make it more difficult to apply linkage data to genotype prediction in this disease.

Child↗
PubMed1982

Potentiated state of the tropomyosin actin filament and nucleotide-containing myosin subfragment 1.

The main purpose of this study was to determine whether potentiation of acto-S-1 ATPase activity (activity higher than that obtained with tropomyosin-free actin) could be caused by nucleotide-containing acto-S-1 complexes. In addition, we wanted to know whether these complexes also have a positive cooperative effect on their own apparent binding constant under conditions where nucleotide-free acto-S-1 complexes cause potentiation of ATPase activity. Using calcium-saturated troponin-tropomyosin actin filaments, we observed potentiation of ATPase activity in the presence of 5.0 mM magnesium 5'-adenylyl imidodiphosphate (MgAMPPNP) and calculated that the ability of acto-S-1-AMPPNP complexes to cause potentiation must have been very similar to that of nucleotide-free acto-S-1 complexes. In extension of earlier studies, potentiated acto-S-1 ATPase activity was characterized by an increase in Vmax and, as observed before, a lowering of the apparent Km for subfragment 1 (S-1). Under conditions similar to those that produce the potentiation of acto-S-1 ATPase activity, the apparent actin binding constant of nucleotide-free S-1 was increased about 3-5 fold while the apparent binding constant of AMPPNP to actin-bound S-1 was reduced to (2.5-10) x 10(2) M-1 compared to that of about (1-5) x 10(3) M-1 for S-1 bound to tropomyosin-free actin. Under the same conditions, the apparent binding constant of S-1-AMPPNP to actin was not increased. We suggest that a potentiated state of the tropomyosin actin filament is produced by the cooperative action of acto-S-1 or acto-S-1-AMPPNP complexes. The potentiated state is characterized by an increase in the Vmax of the acto-S-1 ATPase activity, increased binding constants for S-1 and S-1-ADP, and increased binding of tropomyosin to actin.

Actins↗
PubMed1982

Enumeration of antigenic sites of influenza virus hemagglutinin.

The antigenic sites on the hemagglutinin of X-31 (H3) influenza virus have been defined by using a competitive radioimmunoassay with a panel of monoclonal antibodies which includes those known to select variants with substitutions of particular amino acids. The capacity of each monoclonal antibody to block the binding of other radioiodinated monoclones to purified hemagglutinin permitted classification of the panel into four separate groups, each of which defined a particular antigenic site on the hemagglutinin molecule. Three of these are located on the polypeptide backbone and correspond to the "hinge," the "loop," and the "tip/interface" of the X-ray crystallographic model of Wiley et al. (Nature [London] 289:373-378, 1981). Nonreciprocal blocking of certain anti-interface antibodies by anti-loop antibody suggests that much of the exposed surface of the head of the hemagglutinin molecule extending from the loop to the interface may be a continuum of epitopes. A fourth antigenic site is carbohydrate in nature, presumably situated on the antigenic oligosaccharide side chains. These four domains are in addition to two antigenic sites defined by monoclonal antibodies that inhibit neither hemagglutination nor infectivity (Breschkin et al., Virology 113:130-140, 1981;' Yewdell et al., Nature [London] 279:246-248, 1979).

Antibodies, Monoclonal↗
PubMed1981

Cooperativity of the calcium switch of regulated rabbit actomyosin system.

The concentration range required for calcium activation of skeletal myofibrillar ATPase activity has previously been attributed to simultaneous binding of two calcium ions to each troponin. We present data representative of the majority of myofibrillar preparations and data with acto subfragment-1 (S-1) whose calcium activation of ATPase activity occurs over a much too narrow range of calcium concentrations to be so explained. S-1 binding significantly broadened the range of Ca2+ concentrations over which activation occurred but not to the extent that is associated with simultaneous binding of 2 calcium ions.

Actins↗
PubMed1981

Control of cell shape by calcium in the euglenophyceae.

The euglenoid flagellates are able to change their shape rapidly in response to a variety of stimuli, or sometimes spontaneously. Two extremes of shape can be identified: the "relaxed" form is cylindrical; the contracted form is a somewhat distorted disc. These 2 forms can be interconverted by treatments that alter the Ca2+ concentration of the entire cell. The level of Ca2+ is believed to be normally controlled by a system of calcium-accumulating membranes, identified in Astasia longa by the technique of calcium oxalate precipitation. The system forms a set of parallel tubes of endoplasmic reticulum, one of which lies immediately below each of the ridges of the pellicle. The individual ridges, each with its associated reticulum, microtubules and other elements are suggested to be independent motor units. Local activation of a small number of these units by Ca2+ is made possible by the arrangement of Ca2+ -sequestering reticulum, producing the characteristic squirming euglenoid movement. Uniform activation or suppression of all units produces the 2 extremes of shape. The pellicle of A. longa with its associated microtubules has been purified and shown to contain a Ca2+ -binding site and ATPase activity.

Adenosine Triphosphatases↗
PubMed1980

Cholecystectomy and abdominal hysterectomy.

Cholelithiasis is a common disease in women and can lead to serious complications. At Wilford Hall USAF Medical Center, we have performed 21 cholecystectomies at the time of abdominal hysterectomy. All patients had been asymptomatic with regard to gallbladder disease, but showed either preoperative or intraoperative evidence of gallbladder disease. The mean surgical time was 3.3 hours, mean blood loss was 474 mL, and only one patient had febrile morbidity (> 38.3 degrees C). Because of the low morbidity, we recommend that this combined surgical approach be considered by both the gynecologist and general surgeon.

Adult↗