PubMed Health⌕ Search

Biomedical subjects

S Firth

Publications and source records attributed to S Firth.

12 recordsLinked to original sources
PubMed2001

Raman spectroscopy as a means for the identification of plattnerite (PbO2), of lead pigments and of their degradation products.

The Raman spectra of plattnerite [lead(IV) oxide, PbO2] and of the lead pigments red lead (Pb3O4), lead monoxide [PbO, litharge (tetragonal) and massicot (orthorhombic)], lead white [basic lead carbonate, 2PbCO3.Pb(OH)2] and of their laser-induced degradation products were recorded using a range of different excitation lines, spectrometer systems and experimental conditions. The degradation of PbO2 is more extensive along the pathway PbO2-->Pb3O4-->PbO (litharge)-->PbO (massicot) the shorter the wavelength of the excitation line and the higher its power. The Raman spectrum of PbO2, which is black and of the rutile structure, is particularly difficult to obtain but three bands, at 653, 515 and 424 cm-1, were identified as arising from the b2g, a1g and e(g) modes respectively, by analogy with the corresponding modes of isostructural SnO2 (776, 634 and 475 cm-1). A further oxide was identified, PbO1.55, the Raman spectrum of which does not correspond to that of any of the laser-induced degradation products of PbO2 at any of the wavelengths used. The Raman results are critical to the future use of Raman microscopy for the identification of lead pigments on artworks.

Journal Article↗
PubMed2000

Rotavirus VP7 epitope mapping using fragments of VP7 displayed on phages.

cDNA copies of the complete porcine rotavirus CRW-8 VP7 gene were randomly digested to fragments of about 30-60 or 30-500 base pairs by DNase1 in the presence of Mn(2+). The fragments were cloned and expressed in a filamentous phage fd-tet-derived vector to create specific-gene-related peptide libraries. Polyclonal antibodies were then used to pan the SGRP libraries for antibody-binding phages. Analysis of the phage isolates revealed that the majority (86%) of them only had a single insert. However, phages displaying composite inserts containing the VP7 antigenic regions A, B, and C, originally defined by neutralising monoclonal antibody escape mutants, were also isolated. Inserts containing A or C region peptide were found to contain extra sequences from the C region, while the B region epitope was linear and had additional sequence from either upstream or downstream. In addition a dominant and possibly non-neutralising VP7 epitope was identified around amino acids 263-270. One of the recreated antigenic epitopes has also been fused to the outer membrane protein A (OmpA) of Escherichia coli and shown to maintain its antigenicity. The results in this study may have significant implication for recreation of conformational epitopes and vaccine development.

Amino Acid Sequence↗
PubMed1999

Counseling model: creating a healing environment in hospitals.

There are ways in which more holistic approaches to medicine can be achieved through the establishment of alternative hospitals and health-care centers, as has happened in the United States, and changes in midwifery and care for the dying through a more compassionate approach and the use of prescriptive music. Transformations of medical care in The Netherlands are also taking place, with existing hospitals gradually developing more patient-centered approaches and organizations like the Helen Dowling Institute providing tailor-made forms of psycho-social counseling for those with cancer and life-threatening illness.

Counseling↗
PubMed1996

Periplasmic expression of part of the major rotavirus capsid protein VP7 containing all the three antigenic regions in Escherichia coli.

Part of the porcine rotavirus outer capsid protein VP7 containing all the three antigenic regions was expressed as a chimeric protein with bacterial alkaline phosphatase (AP) in E. coli. The construct contains an ompF promoter, the DNA encoding the signal sequence and the first 12 amino acids of mature OmpF, part of vp7 and the DNA encoding mature AP. The chimeric protein is stable, retains the biological property of AP and ability to react with polyclonal antiserum against the virus, and can be exported through the bacterial inner membrane into the periplasm.

Alkaline Phosphatase↗
PubMed1995

Role of intracellular calcium in the regulation of phospholipase A2 in fMet-Leu-Phe-challenged human polymorph neutrophils.

In the present study, we have shown that the protein kinase C (PKC) inhibition by staurosporine augmented fMet-Leu-Phe-(FMLP)-induced arachidonic acid (AA) release in human polymorph neutrophils (PMN). This effect is in contradiction to a recently reported mechanism that besides Ca2+, the phosphorylation of cytosolic phospholipase A2 (cPLA2) is essential for the enzyme activation. In addition, we found that staurosporine elevated the basal concentration of intracellular Ca2+, although initial Ca2+ release was not affected. Since thapsigargin, a blocker of endogenous Ca2+ ATPase, also increased AA release dose-dependently, we believe that the elevation of intracellular Ca2+ is the most essential step and not the phosphorylation of enzyme for the activation of cPLA2.

Arachidonic Acid↗
PubMedDate not supplied

Caregivers of people with multiple sclerosis: a survey in New Zealand.

A survey carried out in the Manawatu and Wanganui area of New Zealand was designed to locate all those known to have multiple sclerosis; as part of the research, 31 primary caregivers (20 males, 11 females) of MS patients in the study were interviewed to gain information about their roles, self-defined tasks, and life situations.

Adaptation, Psychological↗
PubMedDate not supplied

Dimolybdenum bis((S,S,S)-triisopropanolaminate(3-)): a blue compound with an unusual Mo-Mo triple bond.

Mo2(OtBu)6 and Mo2(NMe2)6 each react with (S,S,S)-triisopropanolamine (2 equiv) in benzene to yield dimolybdenum bis((S,S,S)-isopropanolaminate(3-)), Mo2[(OC-(S)-HMeCH2)3N]2 (M identical to M), as a blue crystalline solid. Cell parameters at -160 degrees C: a = 17.389(6) A, b = 10.843(3) A, c = 10.463(3) A, beta = 125.28(1) degrees, Z = 2 in space group C2. The molecular structure involves an Mo2 unit inside an O6N2 distorted cubic box. The Mo2 axis is disordered about three positions with occupancy factors of ca. 45%, 45%, and 10%. Despite this disorder, the molecular structure is shown to contain a central Mo identical to Mo unit of distance 2.15(3) A coordinated to two triolate ligands which each have two chelating arms and one that spans the Mo identical to Mo bond. The local Mo2O6N2 moiety has approximate C2h symmetry, and the Mo-N distances are long, 2.4 A. The 1H and 13C(1H) NMR spectra recorded in benzene-d6 are consistent with the geometry found in the solid-state structure. The blue color arises from weak absorptions, epsilon approximately 150 dm3 mol-1 cm-1, at 580 and 450 nm in the visible region of the electronic absorption spectrum. Raman spectra recorded in KCl reveal pronounced resonance effects with excitation wavelengths of 488.0, 514.5, and 568.2 nm, particularly for the 322 cm-1 band, which can probably be assigned to nu(Mo identical to Mo). The electronic structure of this compound is investigated by B3LYP DFT calculations, and a comparison is made with the more typical ethane-like (D3d) Mo2(OR)6 compounds is presented. The distortion imposed on the molecule by the triisopropanolaminate(3-) ligands removes the degeneracy of the M-M pi molecular orbitals. The HOMO and SHOMO are both M-M pi and M-O sigma* in character, while the LUMO is M-M pi* and the SLUMO is predominantly M-O sigma* with metal sp character. The calculated singlet-singlet transition energies are compared with those implicit in the observed electronic spectrum.

Journal Article↗