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Biomedical subjects

G E Wilson

Publications and source records attributed to G E Wilson.

At least 37 records · Page 2Linked to original sources
PubMed1992

Desmoplastic malignant mesothelioma: a review of 17 cases.

AIMS: To identify the histological features of desmoplastic mesothelioma, and to determine its incidence and prognosis. METHODS: Two hundred and fifty five cases of malignant mesothelioma were examined over seven years (1982-9) to identify the desmoplastic variant. Sections were cut at 5 microns and stained with haemotoxylin and eosin and with CAM 5.2 (Dakopatts). Asbestos fibre counts were carried out by light microscopy in 14 cases using the potash digestion method. RESULTS: Seventeen cases were identified as desmoplastic mesothelioma giving an incidence of 6.6%. In 11 cases the cell type in more cellular areas was sarcomatous and in six others it was biphasic. The mean survival time from onset of symptoms to death was 5.8 months for the sarcomatous variant and 6.8 months for the biphasic variant. Twelve of 16 patients had had previous occupational exposure to asbestos, ranging from five months to 43 years. The diagnosis of desmoplastic mesothelioma was only accepted if acellular connective tissue comprised 50% or more of the tumour bulk. Also seen was collagen necrosis, anastomosing bands of often hyalinised collagen with a prominent storiform pattern, and where cellular detail was present there were hyperchromatic nuclei. CONCLUSIONS: Desmoplastic mesothelioma is a rare variant of malignant mesothelioma with a storiform collagen pattern, collagen necrosis, bland acellular collagen and focal cytological features of malignancy. Though rare, it is important to recognise this variant and distinguish it from a pleural plaque, nonspecific reactive pleural fibrosis, pleurisy, rheumatoid disease, or, rarely, spindle cell sarcomas.

Adult↗
PubMed1991

Characterization of cross-linking of cell walls of Bacillus subtilis by a combination of magic-angle spinning NMR and gas chromatography-mass spectrometry of both intact and hydrolyzed 13C- and 15N-labeled cell-wall peptidoglycan.

Cross-polarization magic-angle spinning 13C and 15N NMR, rotational-echo double resonance 13C NMR, and delays alternating with nutation for tailored excitation-difference 13C NMR spectra have been obtained from lyophilized cell walls of Bacillus subtilis grown on a synthetic medium containing D,L-[2-13C, 15N]aspartate and D-[1-13C]alanine. Label from aspartate is incorporated into D-glutamic acid and m-diaminopimelic acid of cell-wall peptidoglycan, while label from alanine appears in the C-1 positions of both D- and L-alanyl residues. The cross-link index (the fraction of peptide stems joined by an isopeptide covalent bond) is obtained directly from analysis of the results of the 13C NMR experiments. However, specific isotopic enrichments of cell-wall components cannot be obtained from NMR data alone. The latter are determined either from a gas chromatographic-mass spectrometric analysis of the amino acids derived from hydrolysis of cell-wall peptidoglycan, or from a combination of NMR and gas chromatographic-mass spectrometric results. The combined analysis is overdetermined and so involves the least error for evaluations of both the cross-link index and the isotopic enrichments. The cross-link index is 0.33 +/- 0.03 for cell walls of B. subtilis grown in the presence of the antibiotic, cephalothin.

Amino Acids↗
PubMed1991

A multiple mass spectral line method for determining positional specific activities in stable isotope-labeled amino acids.

A method for determining the position and enrichment of isotope labels in amino acids using gas chromatography/mass spectrometry is described. [alpha-15N]- and [epsilon-15N]lysine, [1-13C]- and [15N]alanine and -leucine, and [1-13C]-, [2-13C]-, [3-13C]-, and [4-13C]aspartic acid were investigated. Standards for each isotope label were prepared and analyzed under scan conditions, and line pairs characteristic for the label were identified. The standards were reanalyzed under selective ion monitoring conditions to verify the behavior of the line pairs. Mixtures of amino acids containing different isotope labels or the same label in different positions were prepared and analyzed under selective ion monitoring conditions. Enrichments were determined with high precision and relative errors ranging from 0.14 to 36%.

Amino Acids↗
PubMed1990

The use of multiple mass spectral line pairs for enhanced precision in isotope enrichment studies of 15N-labeled amino acids.

A method for enhancing the precision in the calculation of isotope enrichment for 15N-labeled amino acids is presented. The method utilizes multiple line pairs for the calculation of isotope enrichment. Using multiple line pairs allows the evaluation of calibration curves for nonlinear behavior and permits differentiation among sites containing more than one labeled nitrogen. The increase in precision is related to the number of isotopically shifted line pairs used in calculating the isotopic enrichment and varies with the amino acid of interest.

Amino Acids↗
PubMed1990

Severe granulomatous arthritis due to spinous injury by a "sea mouse" annelid worm.

A case of destructive arthritis and soft tissue granulomatous inflammation occurred in a 25 year old man who had injured his right index finger while snorkelling in the Mediterranean. It was initially thought that he had fallen on a sea-urchin. He removed some spines at the time of injury but the finger became stiff, swollen, and painful, and after eight months with no symptomatic improvement amputation through the proximal phalanx was performed. Examination showed an exuberant granulomatous and foreign body type inflammation in the dermis and subcutaneous tissues and affecting the bone, with erosion of the cartilaginous surfaces of the proximal interphalangeal joint. Spines present in soft tissue sections contained no calcium but did contain chitin as shown by a von Wisseling reaction for chitosan. It is concluded that the chitinous spines almost certainly came from a sea-mouse (Phylum Annelida, family Aphroditidae). Sea mice are inconspicuous creatures which live on the sea floor and which may cause some injuries thought to be attributable to sea-urchins.

Adult↗
PubMed1986

Characterization of peptidoglycan stem lengths by solid-state 13C and 15N NMR.

Lyophilized whole cells of Aerococcus viridans (Gaffkya homari) grown on a synthetic medium containing D-[2-13C, 15N]Ala, or containing both L-[1-13C]Lys and D-[15N]Ala, have been examined by double cross-polarization magic-angle spinning 13C and 15N nuclear magnetic resonance. Results from the double-labeled alanine experiment confirm the absence of metabolic scrambling of alanine by A. viridans. Results from the combined single-label experiment can be used to count directly the number of adjacent L-Lys and D-Ala units in peptide chains of cell-wall peptidoglycan. This count leads to the conclusion that there are no terminal D-Ala or D-Ala-D-Ala units in uncross-linked chains of the peptidoglycan of A. viridans.

Alanine↗
PubMed1986

Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: quasi-elastic light scattering studies.

The effects of hydrochloric acid on mixed gels of aluminum and magnesium hydroxide and on magaldrate have been examined using quasi-elastic light scattering. Particles of magaldrate and mixed gels behave differently. The magaldrate particles initially decrease in size in response to increasing amounts of hydrochloric acid up to that sufficient to neutralize all the magnesium hydroxide present, then increase in size to approximately 2 microns. The composition of the mixed gels appears to be particularly important in determining the reaction with limited amounts of acid. For these particles, which are thought to consist of a magnesium hydroxide core surrounded by an aluminum hydroxide sheath, slow erosion of the aluminum hydroxide was apparently followed by complete disintegration of the particles. Particles which remain grow in size to approximately 3 microns.

Aluminum Hydroxide↗
PubMed1985

Solid-state 13C and 15N nuclear magnetic resonance studies of alanine metabolism in Aerococcus viridans (Gaffkya homari).

Transport and metabolism of D- and L-alanine by Aerococcus viridans (Gaffkya homari) have been studied using cross-polarization magic-angle spinning 13C and 15N NMR spectroscopy of lyophilized whole cells, isolated cell walls, and crude extracts. For equimolar concentrations in the growth medium, about 10 times more D-alanine than L-alanine is transported into the cells. Examination of cells labeled with D-[13C]alanine and L-[epsilon-15N]lysine by double cross-polarization magic-angle spinning 15N NMR indicates that only about 20% of the D-alanine present in cell-wall peptidoglycan comes directly from the growth medium. The rest is produced by de novo synthesis. Most of the labeled D-alanine is found within peptidoglycan precursors or inverted to L-alanyl residues of soluble proteins.

Alanine↗
PubMed1985

Solid-state 15N NMR studies of the effects of penicillin on cell-wall metabolism of Aerococcus viridans (Gaffkya homari).

Lyophilized whole cells and isolated cell walls from Aerococcus viridans (Gaffkya homari) grown on a synthetic medium containing benzylpenicillin, and either L-[epsilon-15N]lysine or 15N-ammonium ion as the only source of label, have been studied using cross-polarization magic-angle spinning 15N nuclear magnetic resonance. The lysine is incorporated directly into protein and cell-wall peptidoglycan and was used to measure cell-wall cross-links. The ammonium ion acts as a non-specific label monitoring general metabolism. Inhibition of cell-wall cross linking by penicillin occurs, but may not be the exclusive cause of cell death and lysis in this microorganism. Instead, the disruption of the mechanism for control of peptidoglycan synthesis probably is a contributing factor.

Cell Wall↗
PubMed1985

Action of hydrochloric acid on aluminum hydroxide-magnesium hydroxide gels and magaldrate: 27Al NMR and pH-stat studies.

Neutralization of mixtures of aluminum hydroxide-magnesium hydroxide gels and of magaldrate by hydrochloric acid were studied by 27Al NMR under conditions of both equilibrium and kinetic control. Under conditions where equilibrium has been attained, an aluminum NMR signal is detectable for suspensions of the mixed gels and magaldrate only after enough acid has been added to exhaust the acid-neutralizing capacity of the magnesium hydroxide. Mixed gels seem to form several soluble aluminum-containing species as neutralization proceeds. Under the conditions of the modified Beekman neutralization procedure, in which the species concentrations reflect neutralization kinetics, mixed gels show a sharp burst of the hexaaquoaluminum cation as acid is added followed by a slow loss of that cation from solution and an accompanying slow rise in pH. Magaldrate shows a steady increase in the hexaaquoaluminum cation with added acid. Differences between magaldrate and mixed gels are also apparent in pH-stat titrations in which magaldrate displays a biphasic response, contrasting to the two burst phases with an intervening lag phase observed for mixed gels. The results of the 27Al NMR and pH-stat titrations are consistent with the hypotheses that magaldrate is a homogeneous substance with a hydrotalcite-like structure and that mixed gels consist of a magnesium hydroxide core surrounded by aluminum hydroxide.

Aluminum↗
PubMed1983

Direct measurement of peptidoglycan cross-linking in bacteria by 15N nuclear magnetic resonance.

Cross-polarization magic angle spinning 9.12-MHz 15N nuclear magnetic resonance was used to measure the extent of peptidoglycan cross-linking within intact bacterial cells and isolated cell walls of Aerococcus viridans ATCC 10400 grown in the presence of L-[epsilon-15N]lysine. A value of 49% for the cross-linking index was found for normal cells, while for those grown in the presence of low levels of penicillin G (0.1 micrograms/ml), the cross-linking index was reduced to 35%.

Magnetic Resonance Spectroscopy↗
PubMed1980

Characterization of rabbit myocardial phospholipids with 31P nuclear magnetic resonance.

To reduce chemical modifications of phospholipids during extraction and analysis, we developed and evaluated a method for analyzing tissue phospholipids with 31P NMR. Our results indicate: (1) 31P NMR of chloroform/methanol tissue extracts is a convenient and rapid technique for characterizing myocardial phospholipids. (2) Normal rabbit myocardium contains little, if any, lysoglycerophospholipid. (3) Conventional extraction and chromatography of phospholipids may convert choline and ethanolamine plasmalogens to lysoglycerophospholipids by acid-catalyzed hydrolysis.

Animals↗