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S Cusack

Publications and source records attributed to S Cusack.

At least 55 records · Page 3Linked to original sources
PubMed1993

The introduction of automatic blood pressure monitoring to an accident & emergency resuscitation room.

Machines for automatic non-invasive blood pressure (BP) monitoring are increasingly available in British accident and emergency departments. Our department recently acquired two machines with this capability for use in the resuscitation room. This provided us with an opportunity to compare the speed and frequency of automatic BP recording with the previously used manual method. We found no significant difference in either the median time to the first recording of BP or in the median number of documented recordings in the first hour. However, the overall frequency of BP recording did show a statistically significant increase. We conclude that automation alone does not improve standard practice in this area greatly.

Automation↗
PubMed1992

A new crystal form of the complex between seryl-tRNA synthetase and tRNA(Ser) from Thermus thermophilus that diffracts to 2.8 A resolution.

Two distinct complexes between seryl-tRNA synthetase and tRNA(Ser) from Thermus thermophilus have been crystallized using ammonium sulphate as a precipitant. Form III crystals grow from solutions containing a 1:2.5 stoichiometry of synthetase dimer to tRNA. They are of monoclinic space group C2 with unit cell dimensions a = 211.6 A, b = 126.8 A, c = 197.1 A, beta = 132.4 degrees and diffract to about 3.5 A. Preliminary crystallographic results show that the crystallographic asymmetric unit contains two synthetase dimers. Form IV crystals grow from solutions containing a 1:1.5 stoichiometry of synthetase dimer to tRNA. They are of orthorhombic space group P2(1)2(1)2(1) with unit cell dimensions a = 124.5 A, b = 128.9 A, c = 121.2 A and diffract to 2.8 A resolution. Preliminary crystallographic results show that these crystals contain only one tRNA molecule bound to a synthetase dimer.

Crystallization↗
PubMed1992

New triple-helical model for the shaft of the adenovirus fibre.

The adenovirus fibre is a trimeric protein with a globular head on a long thin shaft that projects from the twelve fivefold vertices of the virion. The shaft region of the fibre primary sequence has a unique pseudo-repeating motif of 15 residues. Using constraints derived from sequence analysis, the trimeric nature of the fibre, the experimental determination of the shaft length and general knowledge about protein structure, an atomic model of the fibre shaft has been constructed by computer modelling techniques. In the final model the three monomers form a left-handed triple-helical structure with threefold symmetry and with successive 15-residue repeats on the same chain related by an axial rise of 13.1 A and a left-handed azimuthal rotation of close to 300 degrees. Three threefold related beta-sheets with short strands are formed by inter-monomer main-chain hydrogen bonds giving rise to superhelical ribbons covering the surface of the shaft. The model satisfies criteria of extensive hydrogen bonding, reasonable backbone torsion angles, burial of most hydrophobic residues and good packing of the hydrophobic core. Furthermore, the model is consistent with the observed shaft length of about 290 A and its calculated X-ray fibre diffraction patterns shows the characteristic features found in the diffraction pattern of crystals of fibre, notably layer lines with a spacing of about 1/26 A-1 and strong meridional intensity at 1/4.4 A-1.

Adenoviruses, Human↗
PubMed1992

Crystallization of the seryl-tRNA synthetase-tRNA(Ser) complex from Thermus thermophilus.

The complex between seryl-tRNA synthetase and its cognate tRNA from the extreme thermophile Thermus thermophilus has been crystallized from ammonium sulphate solutions. Two different tetragonal crystal forms have been characterized, both diffracting to about 6 A using synchrotron radiation. One form grows as large bipyramids and has cell dimensions a = b = 127 A, c = 467 A, and the second form occurs as long, thin square prisms with cell dimensions a = b = 101 A, c = 471 A. Analysis of washed and dissolved crystals demonstrates the presence of both protein and tRNA.

Crystallization↗
PubMed1992

The 2.2 A resolution crystal structure of influenza B neuraminidase and its complex with sialic acid.

Influenza virus neuraminidase catalyses the cleavage of terminal sialic acid, the viral receptor, from carbohydrate chains on glycoproteins and glycolipids. We present the crystal structure of the enzymatically active head of influenza B virus neuraminidase from the strain B/Beijing/1/87. The native structure has been refined to a crystallographic R-factor of 14.8% at 2.2 A resolution and its complex with sialic acid refined at 2.8 A resolution. The overall fold of the molecule is very similar to the already known structure of neuraminidase from influenza A virus, with which there is amino acid sequence homology of approximately 30%. Two calcium binding sites have been identified. One of them, previously undescribed, is located between the active site and a large surface antigenic loop. The calcium ion is octahedrally co-ordinated by five oxygen atoms from the protein and one water molecule. Sequence comparisons suggest that this calcium site should occur in all influenza A and B virus neuraminidases. Soaking of sialic acid into the crystals has enabled the mode of binding of the reaction product in the putative active site pocket to be revealed. All the large side groups of the sialic acid are equatorial and are specifically recognized by nine fully conserved active site residues. These in turn are stabilized by a second shell of 10 highly conserved residues principally by an extensive network of hydrogen bonds.

Amino Acid Sequence↗
PubMed1992

Flying squad response to out-of-hospital cardiac arrest--a decade of experience.

The Flying Squad (MEDIC I) based at the Royal Infirmary, Edinburgh, commenced operation in 1980. The MEDIC I response to out of hospital non-traumatic cardiac arrest over the past decade is reported. On-scene resuscitation was attempted in 384 patients. A total of 149 (39%) patients were successfully resuscitated and transferred to hospital. Thirty-six (9.4%) patients survived to discharge from hospital. Patients receiving basic life support prior to the arrival of MEDIC I and in ventricular fibrillation had a survival rate of 14.5% (25/174). During 1988-89, 21 patients were initially attended by ambulance crews equipped with semi-automatic external defibrillators and eight (38%) of these patients survived. The response of a hospital-based flying squad to support trained ambulance crews, especially when equipped with a defibrillator may provide an economically and operationally feasible alternative to training all first responders in the full range of paramedic skills.

Adolescent↗
PubMed1992

Exposure of the hands to ionizing radiation in the resuscitation room of an accident & emergency department.

Exposure of the hands to ionizing radiation in the resuscitation room of an A&E department was measured in eight health care personnel over 3 consecutive months. The radiation levels did not exceed those limits currently recommended by the International Commission on Radiological Protection 1990. The level recorded in one individual did exceed the level set at the Lothian Health Boards investigation limit. In only five of 85 occasions were lead gloves worn by the doctor during cross table lateral cervical radiographs. Recommendations are made for reducing the radiation exposure to the hands.

Emergency Service, Hospital↗
PubMed1991

Sequence, structural and evolutionary relationships between class 2 aminoacyl-tRNA synthetases.

Class 2 aminoacyl-tRNA synthetases, which include the enzymes for alanine, aspartic acid, asparagine, glycine, histidine, lysine, phenylalanine, proline, serine and threonine, are characterised by three distinct sequence motifs 1,2 and 3 (reference 1). The structural and evolutionary relatedness of these ten enzymes are examined using alignments of primary sequences from prokaryotic and eukaryotic sources and the known three dimensional structure of seryl-tRNA synthetase from E. coli. It is shown that motif 1 forms part of the dimer interface of seryl-tRNA synthetase and motifs 2 and 3 part of the putative active site. It is further shown that the seven alpha 2 dimeric synthetases can be subdivided into class 2a (proline, threonine, histidine and serine) and class 2b (aspartic acid, asparagine and lysine), each subclass sharing several important characteristic sequence motifs in addition to those characteristic of class 2 enzymes in general. The alpha 2 beta 2 tetrameric enzymes (for glycine and phenylalanine) show certain special features in common as well as some of the class 2b motifs. In the alanyl-tRNA synthetase only motif 3 and possibly motif 2 can be identified. The sequence alignments suggest that the catalytic domain of other class 2 synthetases should resemble the antiparallel domain found in seryl-tRNA synthetase. Predictions are made about the sequence location of certain important helices and beta-strands in this domain as well as suggestions concerning which residues are important in ATP and amino acid binding. Strong homologies are found in the N-terminal extensions of class 2b synthetases and in the C-terminal extensions of class 2a synthetases suggesting that these putative tRNA binding domains have been added at a later stage in evolution to the catalytic domain.

Adenosine Triphosphate↗
PubMed1991

Sequence and crystallization of influenza virus B/Beijing/1/87 neuraminidase.

Influenza B/Beijing/1/87 neuraminidase heads were isolated from virus via trypsin digestion and characterized by PAGE, N-terminal sequencing, electron microscopy, and enzyme activity. The heads were crystallized into two crystal forms; tetragonal plates, like other neuraminidase crystals described before, that diffract to medium resolution (3 A) and a new form consisting of trigonal prisms or needles that diffract to high resolution (at least 2 A). The gene segment coding for neuraminidase was sequenced and compared with the neuraminidase sequence of B/Lee/40. The deduced amino acid sequences for neuraminidase showed only a 7% difference, whereas those for the NB proteins differed by 20%.

Amino Acid Sequence↗
PubMed1990

Structure of adenovirus fibre. I. Analysis of crystals of fibre from adenovirus serotypes 2 and 5 by electron microscopy and X-ray crystallography.

An analysis by electron microscopy in amorphous ice and X-ray diffraction of four types of three-dimensional crystals of adenovirus fibre is presented. Fibre from adenovirus type 2 (Ad2) crystallizes in two forms depending on whether it is native or cleaved near the N terminus at Tyr17. Fibre from Ad5 also crystallizes in two forms, both of which contained fibre cleaved at Tyr17. Analysis of the packing of the fibres in each of these crystals suggests that the overall length of the fibre may be considerably longer (about 350 to 370 A) than previously reported. Crystals of cleaved Ad2 fibre are of sufficient quality to be characterized by X-ray diffraction. They are of space group C2 and cell dimensions a = 134.4 A, b = 77.6 A, c = 539.4 A, beta = 92.7 degrees. These crystals are remarkable in that, despite being monoclinic, the ab plane forms a perfect hexagonal lattice. This is explained by a trigonal packing of the trimeric fibre heads in the crystal. A similar feature is found for one type of Ad5 crystal, although the hexagonal lattice is 12% smaller. The crystals of cleaved Ad2 show very strong meridional intensity at a Bragg spacing of 4.4 A and weaker diffuse intensity corresponding to layer-lines of spacing 26.4 A. This must reflect the quasiperiodicity of the structure of the fibre shaft, which is apparent in the primary sequence. The occurrence of these features combined with the new determination of the length of the fibre (see also the accompanying paper) require a reappraisal of the cross-beta model of the fibre shaft proposed by Green et al.

Adenoviridae↗
PubMed1990

A second class of synthetase structure revealed by X-ray analysis of Escherichia coli seryl-tRNA synthetase at 2.5 A.

The three-dimensional crystal structure of seryl-transfer RNA synthetase from Escherichia coli, refined at 2.5 A resolution, is described. It has an N-terminal domain that forms an antiparallel alpha helical coiled-coil, stretching 60 A out into the solvent and stabilized by interhelical hydrophobic interactions and an active-site alpha-beta domain based around a seven-stranded antiparallel beta sheet. Unlike the three other known synthetase structures, the enzyme contains no classical nucleotide-binding fold, and is the first representative of a second class of aminoacyl-tRNA synthetase structures.

Amino Acid Sequence↗
PubMed1990

Temperature dependence of the low frequency dynamics of myoglobin. Measurement of the vibrational frequency distribution by inelastic neutron scattering.

Inelastic neutron scattering spectra of myoglobin hydrated to 0.33 g water (D2O)/g protein have been measured in the low frequency range (1-150 cm-1) at various temperatures between 100 and 350 K. The spectra at low temperatures show a well-resolved maximum in the incoherent dynamic structure factor Sinc(q, omega) at approximately 25 cm-1 and no elastic broadening. This maximum becomes gradually less distinct above 180 K due to the increasing amplitude of quasielastic scattering which extends out to 30 cm-1. The vibrational frequency distribution derived independently at 100 and 180 K are very similar, suggesting harmonic behavior at these temperatures. This result has been used to separate the vibrational motion from the quasielastic motion at temperatures above 180 K. The form of the density of states of myoglobin is discussed in relation to that of other amorphous systems, to theoretical calculations of low frequency modes in proteins, and to previous observations by electron-spin relaxation of fractal-like spectral properties of proteins. The onset of quasielastic scattering above 180 K is indicative of a dynamic transition of the system and correlates with an anomalous increase in the atomic mean-squared displacements observed by Mössbauer spectroscopy (Parak, F., E. W. Knapp, and D. Kucheida. 1982. J. Mol. Biol. 161: 177-194.) and inelastic neutron scattering (Doster, W., S. Cusack, and W. Petry, 1989. Nature [Lond.]. 337: 754-756.) Similar behavior is observed for a hydrated powder of lysozyme suggesting that the low frequency dynamics of globular proteins have common features.

Deuterium↗
PubMed1990

Non-traumatic chest pain in young adults: a medical audit.

Four hundred consecutive young patients who attended an accident and emergency department with non-traumatic chest pain as their primary complaint were reviewed. They represented 0.7% of total new attendances. Most were self-referrals, but ambulance transport was requested for over 25%. The majority of investigations (mainly chest radiography and electrocardiography) performed in this group of patients were normal; however, almost one in six investigations was judged to be abnormal. Although this group of patients is at low risk for serious cardiorespiratory disease, a small but significant number of underlying (mainly non-cardiac) disorders was found and 22.5% (90) required in-patient admission. In contrast, almost one-fifth of patients received no specific diagnosis, while almost 40% were deemed to require no follow-up.

Adolescent↗
PubMed1989

Dynamical transition of myoglobin revealed by inelastic neutron scattering.

Structural fluctuations in proteins on the picosecond timescale have been studied in considerable detail by theoretical methods such as molecular dynamics simulation, but there exist very few experimental data with which to test the conclusions. We have used the technique of inelastic neutron scattering to investigate atomic motion in hydrated myoglobin over the temperature range 4-350 K and on the molecular dynamics timescale 0.1-100 ps. At temperatures below 180 K myoglobin behaves as a harmonic solid, with essentially only vibrational motion. Above 180 K there is a striking dynamic transition arising from the excitation of nonvibrational motion, which we interpret as corresponding to torsional jumps between states of different energy, with a mean energy asymmetry of 12 kJ mol-1. This extra mobility is reflected in a strong temperature dependence of the mean-square atomic displacements, a phenomenon previously observed specifically for the heme iron by Mössbauer spectroscopy, but on a much slower timescale (10(-7) s). It also correlates with a glass-like transition in the hydration shell of myoglobin and with the temperature-dependence of ligand-binding rates at the heme iron, as monitored by flash photolysis. In contrast, the crystal structure of myoglobin determined down to 80 K shows no significant structural transition. The dynamical behaviour we find for myoglobin (and other globular proteins) suggests a coupling of fast local motions to slower collective motions, which is a characteristic feature of other dense glass-forming systems.

Algorithms↗