Search Results - (Author, Cooperation:J. Carson)

2018-08-02

The American Society for Microbiology (ASM)

0099-2240

1098-5336

Biology

2018-10-02

The Society of Nuclear Medicine (SNM)

0022-3123

Medicine

2015-10-10

Nature Publishing Group (NPG)

0028-0836

1476-4687

Biology

Chemistry and Pharmacology

Medicine

Natural Sciences in General

Physics

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

We investigate the solvent density driven changes in polymer conformation and phase behavior that occur in a supercritical fluid, with a particular emphasis on conditions near the lower critical solution temperature (LCST) phase boundary. Using continuous space Monte Carlo simulations, the mean square end-to-end distance (R) and radius of gyration (Rg) are calculated for a single chain with 20 Lennard-Jones segments in a monomeric solvent over a broad range of densities and temperatures. The chains collapse as temperature increases at constant pressure, or as density decreases at constant temperature. A minimum in R and Rg occurs at a temperature slightly above the coil-to-globule transition temperature (C-GTT), where the chain adopts a quasi-ideal conformation, defined by the balance of binary attractive and repulsive interactions. Expanded ensemble simulations of finite-concentration polymer–solvent mixtures reveal that the LCST phase boundary correlates well with the single chain C-GTT. At temperatures well above the LCST, the chain expands again suggesting an upper critical solution temperature (UCST) phase boundary above the LCST. © 1997 American Institute of Physics.

Electronic Resource

0004-3249

Art History

Book Reviews

0004-3249

Art History

Book Reviews

0004-3079

Art History

DOCUMENTATION

0004-3249

Art History

2018-01-09

Wiley-Blackwell

0022-3042

1471-4159

Medicine

2018-09-19

National Academy of Sciences

0027-8424

1091-6490

Biology

Medicine

Natural Sciences in General

Artificial Molecular Machines Special Feature

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Myelin was isolated from the brains of mice 15, 20, 30, and 60 days after birth. The total amount of basic protein present in the isolated myelin was determined by radioimmunoassay. The 4 myelin basic proteins, with molecular weights of 21,500, 18,500, 17,000 and 14,000, were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis and their relative amounts were determined densitometrically. The absolute amount of each of the basic proteins was calculated from its relative amount on the gel and from the total amount of myelin basic protein in the sample as determined by radioimmunoassay. The results show that between 10 and 30 days after birth each protein accumulates at a characteristic rate so that the molar ratios among the 4 basic proteins are (in descending order according to their molecular weights) 1:5:2:10 during this period. Between 30 and 60 days after birth the 14 K and 18.5 K proteins continue to accumulate at reduced rates while the 21.5 K and 17 K proteins begin to disappear from the myelin membrane; 60 days after birth the molar ratios among the 4 basic proteins are 1:10:3.5:35. These developmental patterns of accumulation are discussed in relation to the possible role of each of the 4 myelin basic proteins in myelination.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract: We have used tissue culture methods to study the capacity of sensory and sympathetic neurons to synthesize gangliosides. Under appropriate culture conditions, explants of dorsal root or superior cervical ganglia generate an extensive halo of ncurites, which is substantially free of contaminating cells. The cultures incorporate enough [3H]glucosamine into glycolipids to allow biochemical characterization. Gangliosides synthesized by the cells are extracted and freed of radioactive precursors and other lipids by column chromatography. Synthesized material comigrates on (thin-layer chromatograms with the gangliosides, GQ, GT, GD1a, GD1b, and GM1, In addition, a substantial amount of unidentified labeled material migrates in a region between the mono- and disialo bands. The ganglioside profiles show that a similar spectrum of gangliosides is found on the neurites and somata of a particular class of neuron. Furthermore, the ganglioside compositions of the two types of neuron studied appear to be similar. We conclude that both sensory and adrenergic autonomic neurons synthesize gangliosides of each of the major classes and that representatives of each class are found in both somata and neurites. Dispersed cell cultures of the superior cervical ganglion synthesize a repertoire of gangliosides similar or identical to that of explant cultures.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have investigated the role of zinc peptidases in metabolism of the amyloid precursor protein (APP) and the effects of hypoxia. Two peptidase families have been studied: the neprilysin (NEP) family which includes, in the brain: NEP, endothelin converting enzyme (ECE) and secreted endopeptidase (SEP). Reactive oxygen species can regulate enzyme activity via modulation of the zinc ion at the active site. Both NEP and ECE can prevent accumulation of amyloid beta peptide by hydrolyzing the peptide. As acute and chronic hypoxia can modulate APP processing, we have investigated the effects of hypoxia in cell culture on the expression and activity of NEP, ECE and SEP. In parallel, we have monitored the expression of another zinc peptidase, alpha-secretase, that mediates the nonamyloidogenic processing of APP. Overall, zinc peptidases appear neuroprotective and modulation of these activities in pathological states could lead to neurodegeneration.Acknowledgements:  This work was supported by the UK MRC, The Royal Society, INTAS, The Biochemical Society.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Abstract— Brains from 20 day old normal and 20 day old Jimpy mice were fractionated by a modification of the procedure described by Eichberget al. (1964). Each of the fractions obtained was subjected to radioimmunoassay (RIA) for myelin basic protein (MBP). From both the normal brain and the Jimpy brain MBP was recovered in three separate membrane fractions designated P1A. P2A. and P3A. which differed in their sedimentation properties but which had similar densities (less than 1.08 g'ml). In the Jimpy brain compared to normal brain the amounts of P1A and P2A were greatly reduced but the amount of P3A was increased. During development in the normal brain the amount of MBP in the PIA fraction increased in parallel with the accumulation of myelin. The amount of MBP in P2A increased gradually during active myelination and decreased slightly in the adult. The amount of MBP in P3A increased sharply during the period of most active myelination and decreased approx 10-fold as the rate of myelination in the brain declined. Electron microscopic examination revealed that the P1A and P2A fractions from normal brain contained myelin fragments while the P1A and P2A fractions from Jimpy brain contained numerous vesicular membranous structures with little if any identifiable myelin. The P3A fraction from both normal and Jimpy brain contained small vesicles of uniform size, some with polyribosomes attached. Each of the fractions was analyzed by a technique combining sodium dodecyl sulfate polyacrylamide gel electrophoresis with RIA for MBP in order to identify and quantitate the four different forms of MBP with molecular weights of 21.5 K. 18.5 K. 17 K and 14 K dalton. The proportions of the four MBPs were characteristic for each fraction. The relative proportions of the four proteins were 14 K 〉 18.5 K 〉 17 K 〉 21.5 K daltons in all the fractions except P1A Jimpy in which 21.5 K dalton protein was the predominant form of MBP present. The cellular origin of the MBP containing fractions from normal and Jimpy brain is discussed.

Electronic Resource

1467-9310

Blackwell Publishing Journal Backfiles 1879-2005

Economics

This paper describes a management aid devised to illustrate the inter-relationships between present company business activities and the investigational activities of the various company R&D functions. It is based on the- construction of a three-dimensional model in which the raw material, process and market parameters are the axes. Use of the model can facilitate project definition and selection in R and D departments and can be extended as a management aid in studies of R & D resource allocation and acquisition studies.

Electronic Resource

1365-2303

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Introduction  Fine needle aspiration cytology is regarded as the gold standard investigation in diagnosis of thyroid swellings. Published data suggest an overall accuracy rate of 75%1 in the detection of thyroid malignancy. The aim of this study was to determine the accuracy of FNA cytology in detection of thyroid malignancy in our surgical unit.Methods  Between 1989–2002, 144 patients who underwent thyroid resection by single consultant surgeon and who had pre-operative FNA were enrolled in this retrospective study. The pre-operative FNA results were compared with definitive histological diagnosis following thyroid resection. Fine needle aspiration cytology was performed using aspirate and non-aspirate techniques on each thyroid swelling. The cytological sample was assessed by a single cytopathologist and was classified as inadequate, non-neoplastic, neoplastic, suspicious or indeterminate. The histology was classified as non-neoplastic (benign) and neoplastic (malignant).Results  Fine needle aspiration cytology analysis revealed 94 (13.88%) non-neoplastic, six (65.27%) neoplastic and 20 (4.16%) suspicious aspirates. Twenty (13.88%) samples were inadequate and four (2.77%) samples were indeterminate. Histological analysis showed 118 (81.94%) benign, 26 (18.05%) malignant specimens. Fine needle aspiration cytology had a sensitivity, specificity and accuracy rate of 52.6%, 86.6% and 79.1%, respectively for diagnosing thyroid malignancy.Conclusion  The results are comparable with the current published data and demonstrate that FNA cytology in our hands is accurate investigation for pre-operative diagnosis for the detection of thyroid malignancy.

Electronic Resource

1471-4159

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We report (a) that the shiverer mutation has pleiotropic phenotypic effects on myelin basic protein expression in the CNS of homozygous (shi/shi) mice and (b) that each of the effects of the shiverer allele is expressed co-dominantly with the wild-type allele in heterozygous (+/shi) animals. First, the total amount of myelin basic protein, as determined by radioimmunoassay, that accumulates in the CNS is approximately 0.1% of the wildtype amount in shi/shi animals and approximately 50% in +/shi animals. Second, the four major forms of myelin basic protein, with molecular weights of 21,500, 18,500, 17,000, and 14,000, that are present in wild-type mouse CNS are undetectable in either whole brain or purified myelin of shi/shi animals, and each of the four proteins is reduced commensurately in brain and myelin of +shi animals. Third, the small amount of myelin basic protein-related material that does accumulate in the shi/shi brain consists of several polypeptides, with molecular weights ranging from 25,000 to 100,000, the pattern of which is different from that found in wild-type brain. The pattern of myelin basic protein-related polypeptides in +lshi brain is a composite of the wild type and the shiverer mutant. Fourth, messenger RNA from shi/shi brain, when translated in vitro, encodes a set of myelin basic protein-related polypeptides qualitatively similar to that encoded by wild-type messenger RNA, except that the 18,500 and 14,000 translation products are greatly reduced, while other myelin basic protein-related translation products are spared. The pattern of myelin basic protein-related translation products for +/shi messenger RNA is intermediate between the patterns for +/+ and shi/shi messenger RNAs. The results suggest that the genetic lesion in the shiverer mutation impinges on the structural gene (or genes) encoding myelin basic protein or on a cis-acting regulatory element controlling that gene (or genes).

Electronic Resource

1365-2222

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

We have investigated the prevalence of atopy within families of cystic fibrosis (CF) patients and compared its frequence in CF patients, their parents and their non-CF siblings. By studying families with two CF patients it was also possible to evaluate the factors influencing the development of atopy in one CF patient relative to the other patient within the same family. A significant correlation with age (P 〈 0.001) for skin test positivity to common allergens within CF sibling pairs was observed. In 14/18 families studied, only the older CF patient was atopic. The presence of atopy in CF patients was independent of the atopic status of their parents.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Previous studies have indicated that when Atlantic salmon, Salmo salar L., are exposed to Neoparamoeba sp. the fish produce anti-Neoparamoeba sp. antibodies. It appears unlikely that these antibodies elicit any specific protection against amoebic gill disease (AGD) as fish with demonstrable activities have been affected by AGD. Experiments were conducted on Atlantic salmon cultured throughout Tasmania to assess the natural production of antibodies towards Neoparamoeba sp. Fish were sampled from areas where AGD was prevalent and from areas where there had been no reported cases. An enzyme-linked immunosorbent assay (ELISA) was used to measure anti-Neoparamoeba sp. antibody activities in serum. All fish from sea water had antibody activities greater than the negative control fish, including fish from areas with no reported cases of AGD. Time trial samples indicated that time after transfer to sea water did not appear to be a significant (P 〉 0.05) factor in antibody activity, however location was (P 〈 0.05). There was no agreement (corrected κ value, 0.16) between the ELISA result and the isolation of Neoparamoeba sp. from the gills of the same fish. The results suggest that Atlantic salmon in seawater culture in Tasmania produce anti-Neoparamoeba sp. antibodies regardless of infection history, suggesting the presence of Neoparamoeba sp. in the environment.

Electronic Resource

1365-2761

Blackwell Publishing Journal Backfiles 1879-2005

Biology

Medicine

Amoebic gill disease is the main disease affecting the salmonid industry in Tasmania, but no information on the distribution of the causative pathogen, Neoparamoeba pemaquidensis, in the aquatic environment is available. This pilot study aimed to determine temporal and spatial distributions of paramoebae species in the water column, using an immuno-dot blot technique. Water samples were collected from inside fish cages at various depths (0.5, 5.5 and 11.0 m) in both summer and winter, as well as various distances (0, 0.5, 240, 280, 750 and 1100 m) away from the sea cage and farming site. Paramoebae densities were estimated using the most probable number technique (MPN). Temperature, salinity, dissolved oxygen, turbidity, nitrite and nitrates, and bacterial counts were measured for each water sample. Data were analysed using a residual maximum likelihood test and significant associations between paramoebae densities and environmental factors were analysed. Results showed that densities were significantly higher in summer (P = 0.017), at 5.5 m depth (P = 0.029), and reduced to the lowest density at 1100 m away from the cage sites (P = 0.008). Bacterial counts, turbidity and temperature were found to be significantly associated with paramoebae densities.

Electronic Resource