Search PubMed⌕ Search

Biomedical subjects

N Shaw

Publications and source records attributed to N Shaw.

70 records · Page 4Linked to original sources
PubMed1968

The lipid composition of Mycoplasma laidlawii strain B.

1. Total lipid was extracted from Mycoplasma laidlawii strain B with chloroform-methanol mixtures and fractionated into neutral lipid, glycolipid and phospholipid components by chromatography on silicic acid. 2. Saponification of the glycolipid fraction, which represented nearly half of the total lipid, yielded two glycosides for which the structures O-alpha-d-glucopyranosyl-(1-->1)-d-glycerol and O-alpha-d-glucopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-d-glycerol were established. 3. The ratio of monoglucosyl diglyceride to diglucosyl diglyceride increased with the age of the culture, though the total glycolipid concentration remained virtually constant. The glycolipid concentration was unaffected by the addition of cholesterol to the culture medium. 4. The phospholipid fraction consisted of two components, phosphatidylglucose and phosphatidylglycerol. Organisms harvested at acidic pH also contained O-amino acyl esters of phosphatidylglycerol. No lipids containing inositol could be detected.

Cholesterol↗
PubMed1968

The glycolipids of Lactobacillus casei A.T.C.C. 7469.

1. The lipids were extracted from Lactobacillus casei A.T.C.C. 7469 with chloroform-methanol mixtures. The glycolipids were obtained by chromatography on silicic acid and DEAE-cellulose (acetate form). 2. Hydrolysis of the glycolipids with alkali gave two glycerol glycosides and a mixture of fatty acids. 3. The glycosides were separated and their structures elucidated. The major component was O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-glycerol and the minor component O-alpha-d-glucopyranosyl-(1-->6)-O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-glycerol. 4. Analysis of the fatty acids by gas-liquid chromatography showed that they were predominantly palmitic acid, octadecenoic acid and lactobacillic acid.

Chloroform↗
PubMed1967

The phospholipids of Pneumococcus I-192R, A.T.C.C. 12213. Some structural rearrangements occurring under mild conditions.

1. The phospholipids from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213, were separated into three fractions by chromatography on columns of silicic acid and DEAE-cellulose (acetate form). 2. The water-soluble phosphate esters produced by deacylation of each fraction were separated by chromatography on columns of DEAE-cellulose (HCO(3) (-) form). 3. Three deacylated products, diglycerol phosphate, glycerylphosphorylglycerol phosphate and bis(glycerylphosphoryl)glycerol, were identified by analysis, by chemical degradations and by comparison with synthetic materials. 4. From a study of freshly isolated lipids prepared and worked up under conditions where exposure to acid was minimal, it was concluded that the Pneumococcus contains phosphatidylglycerol and bisphosphatidylglycerol, in the molar proportion 1:2.5-3.0, and that the deacylation product glycerylphosphorylglycerol phosphate was probably an artifact of the isolation procedure. 5. Acid-catalysed isomerization (phosphodiester migration) of diglycerol phosphate and bis(glycerylphosphoryl)glycerol and transesterification (glycerol phosphate transfer) of diglycerol phosphate were observed. The structures of the products were established by degradation. 6. A novel mechanism for the biosynthesis of bisphosphatidylglycerol is presented.

Cellulose↗
PubMed1967

The structure and possible function of the glycolipid from Staphylococcus lactis I3.

1. The total lipid was extracted from Staphylococcus lactis I3 with chloroform-methanol mixtures and the glycolipid component was isolated by chromatography on silicic acid. 2. Saponification yielded a non-crystalline glycoside for which the structure O-beta-d-glucopyranosyl-(1-->6)-O-beta-d-glucopyranosyl-(1-->1)-d-glycerol has been established by chemical degradations and by comparison with synthetic material. 3. The role of the glycosyl diglycerides in bacterial membranes is discussed.

Chromatography↗
PubMed1966

Bacterial glycolipids. Glycosyl diglycerides in gram-positive bacteria.

1. The lipids of ten Gram-positive bacteria have been isolated and the presence in each of a glycosyl diglyceride was established. 2. The glycolipid fractions were isolated and deacylated to give water-soluble glycosides which were purified by paper chromatography. Partial structures for the glycosides have been deduced from chemical and enzymic studies. 3. Nine of the glycosides were disaccharides glycosidically linked to the 1-position of glycerol: the remaining glycoside contained a trisaccharide similarly linked to glycerol.

Bacillus subtilis↗
PubMed1965

The glycolipids from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213.

1. The total lipid was extracted from the non-capsulated strain of Pneumococcus I-192R, A.T.C.C. 12213, with chloroform-methanol mixtures. Two glycolipids were isolated by chromatography on silicic acid and DEAE-cellulose (acetate form). 2. The major glycolipid was obtained pure in a yield of 640mg./34g. dry wt. of cells and represents about 34% of the total lipid. It contained galactose, glucose, glycerol and fatty acid ester residues in the proportions 1:1:1:2, and yielded on saponification a crystalline non-reducing glycoside. 3. The structure of the glycoside was shown to be O-alpha-d-galactopyranosyl-(1-->2)-O-alpha-d-glucopyranosyl-(1-->1)-d-glycerol. The fatty acids obtained on saponification were identified by gas-liquid partition chromatography of their methyl esters. 4. The minor glycolipid was obtained as a 1:1 (w/w) mixture with the major component, but after saponification the two glycosides were separated by paper chromatography. Evidence was obtained for the structure of the glycoside derived from the minor glycolipid as 1-O-alpha-d-glucosylglycerol. 5. A general method is described for determining the stereochemistry of the glycerol moiety in 1-linked glycerol glycosides.

Journal Article↗
PubMedDate not supplied

A mechanical comparison of first metatarsal diaphyseal osteotomies for the correction of hallux abducto valgus.

The purpose of this study was to perform a mechanical comparison of four commonly performed diaphyseal first metatarsal osteotomies. Fifty first metatarsal-first cuneiform sawbone models were divided equally into five groups: control, offset V, inverted Z, Mau, and Ludloff osteotomy groups. All osteotomies were fixated with two 2.7-mm Synthes cortical screws. Each specimen was then stressed through a computer-controlled hydraulic tensile testing machine while recording the maximum load, energy, stiffness, and fracture pattern. The offset V was superior in terms of maximum load (137.8 N) and energy (0.86 J), as compared to the inverted Z (maximum load 74.7 N and energy 0.24 J), the Mau (maximum load 74.3 N and energy 0.15 J), and the Ludloff (maximum load 67.0 N and energy 0.32 J). The offset V (16.6 N/mm) demonstrated no significant difference in stiffness with the Mau (19.7 N/mm), and was stiffer to the inverted Z (14.4 N/mm) and the Ludloff (9.4 N/mm). We conclude that one could expect a safer and immediate return to weightbearing postoperatively with the offset V osteotomy as compared to the inverted Z, Mau, and Ludloff osteotomies.

Analysis of Variance↗
PubMedDate not supplied

Spatial and temporal accumulation of defense gene transcripts in bean (Phaseolus vulgaris) leaves in relation to bacteria-induced hypersensitive cell death.

Primary leaves of 7- to 9-day-old Red Mexican bean plants were inoculated with virulent or avirulent isolates of Pseudomonas syringae pv. phaseolicola, or saprophytic P. fluorescens either by vacuum infiltration of the whole leaf lamina, or by syringe-inoculation of selected leaf panels. In the incompatible combination, resistance was associated with a hypersensitive response (HR). Syringe-inoculated leaves were sampled in three zones: zone 1, the inoculated leaf area; zone 2, the surrounding 0.5-0.7 cm of leaf tissue; and zone 3, the remainder of the leaf. Northern blots of RNA from zones 1, 2, and 3 were probed with bean cDNAs for phenylalanine ammonia-lyase (PAL), chalcone synthase (CHS), chitinase (CHT), and lipoxygenase (LOX). Accumulation of PAL, CHS, and CHT transcripts was more rapid and generally of greater magnitude in the incompatible than in the compatible interaction and, in both cases, was observed essentially only in zone 1 tissues. Similarly, antibacterial phytoalexins were only detected in zone 1 from the incompatible interaction. Young primary leaves have a background level of LOX transcripts, which declines as leaves age. This decline was accelerated over the first 12 hr postinoculation (hpi) with avirulent bacteria, whereas a weak transient induction, peaking at 5-6 hpi, was observed in the compatible interaction. A subsequent, strong accumulation of LOX transcripts was seen in both the compatible and incompatible interactions outside the inoculation site starting about 14 hpi. LOX transcripts did not accumulate at the inoculation site itself in the incompatible interaction compared to a relatively strong induction in the compatible interaction. Interestingly, inoculation of leaves with cells of the saprophyte P. fluorescens also induced the accumulation of transcripts for CHS, CHT, and LOX, but generally to a lesser degree than in the incompatible interaction. No HR occurred and no macroscopic cell damage was apparent in leaves inoculated with P. fluorescens. However, at the microscopic level individual, trypan blue-stained, necrotic plant cells were visible. In spite of this and the accumulation of CHS transcripts, no phytoalexin accumulation was found up to 48 hr after inoculation. The spatial and temporal relationship of the hypersensitive reaction to defense gene transcript and phytoalexin accumulation is discussed.

Acyltransferases↗
PubMedDate not supplied

Massive gastric hemorrhage induced by buffered aspirin in a greyhound.

A 13-year-old, neutered male greyhound was presented with severe hematemesis and hematochezia following only three doses of buffered aspirin that were within therapeutic recommendations. Transfusion of seven units of whole blood was required to stabilize the patient. Diagnostic evaluation failed to reveal an underlying disease state that could have predisposed the dog to massive gastric hemorrhage. This is the first report of buffered aspirin causing clinically significant disease during routine administration.

Animals↗
PubMedDate not supplied

The portfolio: how was it for you? Views of F2 doctors from the Mersey Deanery Foundation Pilot.

A study was conducted between August 2004 and August 2005 to explore the experiences of Foundation year 2 (F2) trainees who used the learning portfolio on the Mersey Deanery pilot scheme. Seventy-three trainees (77%) reported receiving their portfolio during their induction. In their first four-month placement, 90 trainees (96%) completed the two case-based discussions, 80 (87%) the three mini clinical examinations and 92 (97%) the two direct observation of practical procedures. The number of trainees who felt there was an opportunity to make a record of and analyse clinical critical incidents and critical incidents related to professional behaviour was only 32 (35%) and 13 (15%) respectively. Free text responses suggested that trainees appreciate the portfolio but that an understanding of its content and purpose, particularly by educational supervisors, is paramount to its success.

Clinical Competence↗