Search PubMed⌕ Search

Biomedical subjects

P Kemp

Publications and source records attributed to P Kemp.

At least 37 records · Page 2Linked to original sources
PubMed1987

A comparison of retrobulbar block produced by etidocaine 1% and by a mixture of lidocaine 2% and bupivacaine 0.75%.

In this double-blind study, retrobulbar block for cataract surgery was produced in 43 patients with etidocaine 1% and in 37 patients with a mixture of equal volume of lidocaine 2% and bupivacaine 0.75% (final concentrations of 1% and 0.375%, respectively). While a greater proportion of etidocaine-treated patients needed supplemental drug for block, the times of onset of sensory and motor block were not different for the two groups. Compared to treatment with etidocaine, patients treated with the mixture had a slower recovery of motor function. While the proportion of patients reporting postoperative pain was about the same in each group, both the onset of pain and the use of analgesic agents occurred earlier in the group treated with etidocaine. Thus retrobulbar blocks produced by the combination of lidocaine and bupivacaine occurred as rapidly as those produced by etidocaine but had a longer duration.

Acetanilides↗
PubMed1984

Snail shape and growth rates: Evidence for plastic shell allometry in Littorina littorea.

The periwinkle Littorina littorea exhibits morphological variation among southern New England populations that appear to be genetically continuous. In dense populations, individuals have relatively elongate shells in comparison to individuals in sparse populations, which have rounder, globose shells. We experimentally demonstrate that this shell variation is a function of snail growth rate. Rapidly growing snails develop thin, globose shells that accommodate more body mass than thicker, more elongate shells. The implications of these results are discussed in relation to interpreting morphological variation in extant gastropods and in the molluscan fossil record.

Journal Article↗
PubMed1984

The hydrogenation of some cis- and trans-octadecenoic acids to stearic acid by a rumen Fusocillus sp.

The hydrogenation of a range of double-bond positional and configurational octadecenoic acid isomers (cis (delta 2 and delta 4 to delta 13) and trans (delta 2 and delta 5 to delta 13] to stearic acid by a rumen Fusocillus sp. were examined. The cis and trans delta 5 to delta 13 isomers were all hydrogenated to some extent by late-log-phase cultures added to suspensions of individual isomers and incubated for a further 3 h. Of the cis-isomers, delta 5 to delta 11 (79-73% conversion to stearic acid) were the preferred substrates. delta 12-cis- (30%) and delta 13-cis-isomers (5%) were poorly hydrogenated. Of the trans-isomers, delta 8, delta 9 and delta 10 were 45% converted to stearic acid, the other isomers were poorly hydrogenated. These results are in agreement with less extensive studies using sheep rumen micro-organisms. When cultures were grown from small inocula in media containing individual isomers more extensive hydrogenation was found than with late-log-phase cultures. At 24 h, cis delta 2, delta 4 and delta 5 gave the highest conversions to stearic acid (90%) followed by the cis delta 6 to delta 12 and trans delta 8 to delta 10 isomers (approximately 75%), although at 6 and 12 h delta 9-trans gave higher yields of stearic acid than delta 9-cis, probably because the growth of the cis cultures showed a longer log-phase.

Animals↗
PubMed1984

The hydrogenation of the series of methylene-interrupted cis,cis-octadecadienoic acids by pure cultures of six rumen bacteria.

The hydrogenation of all the methylene-interrupted cis,cis-octadecadienoic acids was examined using pure cultures of six rumen bacteria able to hydrogenate linoleic acid to stearic acid or its immediate precursor, trans-11-octadecenoic acid, after first conjugating the linoleic acid to cis,trans-9,11-octadecadienoic acid. Only the delta 14-cis,17-cis-isomer was not hydrogenated by at least one of the bacteria and no evidence was found that conjugation was necessary before hydrogenation except for the delta 2-cis,5-cis- and delta 9-cis,12-cis-isomers. Several isomers were hydrogenated to an extent close to that achieved with linoleic acid (delta 9-cis,12-cis). Those bacteria only able to hydrogenate linoleic to trans-11-octadecenoic acid gave only octadecenoic acid products and those bacteria able to hydrogenate linoleic acid to stearic gave variable yields of octadecenoic acids and stearic acid except with the isomers delta 12-cis,15-cis and delta 13-cis,16-cis when only octadecenoic acids were detected. At the substrate levels used (20 micrograms/ml), both inhibition and stimulation of growth were found but no common pattern emerged, nor was the growth consistently related to the extent of hydrogenation.

Animals↗
PubMed1984

The lipids of the rumen fungus Piromonas communis.

The major phospholipids of the anaerobic rumen phycomycete Piromonas communis were phosphatidylethanolamine (38%), phosphatidylcholine (26%) and phosphatidylinositol (13%); no sphingolipids, glycolipids, plasmalogens or phosphonyl lipids were detected. Free fatty acids, triacylglycerols, 1:2 diacylglycerols and a variable amount of 1:3 diacylglycerol were identified, as were minor amounts of squalene and a triterpenol which is probably tetrahymanol. Approximately half the fatty acids were straight chain, even 12 to 24 carbon, saturated acids, the remainder being even 16 to 24 carbon, mono-unsaturated fatty acids. The double bonds in all except the 16 carbon acid were in the omega 9 position. The unsaturation is introduced by a delta 9 desaturase which uses stearic acid as substrate and which does not use oxygen as a terminal electron acceptor. 14C from acetate and glucose was incorporated into the fatty acids of all complex lipids, as were lauric, myristic, palmitic, stearic and oleic acids. [14C]Choline was incorporated into phosphatidylcholine and [14C]ethanolamine into phosphatidylethanolamine and phosphatidylcholine. Label from [14C]serine was recovered in phosphatidylserine and phosphatidylethanolamine, but was not detected in phosphatidylcholine.

Animals↗
PubMed1984

Polystyrene sulphonates and aspiration pneumonia: a histochemical study.

The histochemical characteristics of a sulphonated polystyrene resin were investigated and compared with those of sulphonic acid residues derived from intrinsic tissue components. The major features of the resin particles were their direct Schiff positivity and basophilia. Unlike the tissue sulphonic acids, the resin particles failed to stain with alcian blue. Because of their acid nature, the particles may be responsible for the onset of an aspiration pneumonia if they are accidentally inhaled by debilitated patients.

Aged↗
PubMed1983

The hydrogenation of gamma-linolenic acid by pure cultures of two rumen bacteria.

Two species of rumen bacteria that have been previously shown to partially hydrogenate alpha-linolenic acid have been examined for their ability to hydrogenate gamma-linolenic acid. Free gamma-linolenic acid is hydrogenated in vitro to stearic acid by a rumen Fusocillus sp. (N.C.I.B. 11026), but only to cis,trans-octadec-6,11-enoic acid by a Butyrivibrio sp. The sequential hydrogenations are preceded by a delta 12-cis-delta 11-trans isomerization identical with that observed in the hydrogenation of alpha-linolenic acid and linoleic acid.

Animals↗
PubMed1980

Identification, properties, and differential counts of cell populations using electron microscopy of dry cows secretions, colostrum and milk from normal cows.

Differential counts of electron microscope sections of cell pellets isolated from bovine udder secretions showed that no secretory epithelial cells and very few ductal epithelial cells were present at any stage. The predominant cell type was the macrophage in dry and lactating cows or the polymorphonuclear leucocyte (PMNL) in colostrum. Lymphocytes were also present but no plasma cells were found. The macrophages took up polystyrene latex particles (as did the PMNL) and adhered to glass in culture. Neither macrophage- nor PMNL-rich cell suspensions produced any increase in free fatty acid levels when incubated with fresh milk.

Animals↗
PubMed1979

A new series of long-chain dicarboxylic acids with vicinal dimethyl branching found as major components of the lipids of Butyrivibrio spp.

1. Some members of the genus Butyrivibrio, including a general fatty acid auxotroph (strain S2), contain as a major part of their complex lipids a high-molecular-weight component that is probably formed by the union of two fatty acid chains [Hazlewood & Dawson (1979) J. Gen. Microbiol. 112, 15--27]. 2. Proton and 13C n.m.r. and i.r. and mass spectroscopy were used to examine a homologous series of these moieties and, in addition, the hydrocarbon derivative of one homologue and several synthetic compounds. 3. The results indicate that the high-molecular-weight components are a series of long-chain dicarboxylic acids containing vicinal dimethyl branching, located near the centre of the chain.

Chemical Phenomena↗
PubMed1976

C18 unsaturated fatty acid hydrogenation patterns of some rumen bacteria and their ability to hydrolyse exogenous phospholipid.

1. A number of rumen bacteria isolated because of their ability to deacylate phosphatidyl choline, were found, in addition, to hydrogenate polyunsaturated fatty acids. 2. The most active lipolytic organisms had an unusual pattern of hydrogenation of dietary fatty acids in that alpha-linolenic acid was hydrogenated only as far as trans-11, cis-15-octadecadienoic acid.

Animals↗
PubMed1975

Ultrastructure of the milk fat globule membrane with and without triglyceride.

The primary milk fat globule membrane (MFGM) around freshly secreted milk fat globules consists of a unit membrane separated from the triglyceride core by a dense material. This dense material may widen to include cytoplasmic organelles or may form small blebs. Preincubation and fixation of the globules at temperatures between 4 degrees C and 60 degrees C has no effect on the width or appearance of the dense material. Isolated MFGM profiles show structures identical to those found on intact globules. The dense material on the isolated MFGM profiles is unaffected by extractions which remove essentially all the triglyceride present in the pellets of MFGM. The structure of the primary MFGM is therefore independent of any triglyceride content and the earlier suggestions that the dark material represented a triglyceride layer of high melting point adsorped during cooling of the globules after milking are not supported by the work described in this paper.

Animals↗
PubMed1975

The activation of phospholipase C from Clostridium Welchii by quinine: an absolute requirement for calcium ions.

Quinine activates the hydrolysis of phosphatidyl choline suspensions by phospholipase C (E.C. 3.1.4.3) obtained from Clostridium welchii. Low levels of calcium are an absolute requirement for this activation: Mg2+, Ba2+, Sr2+, and Zn2+ are ineffective. The induction period, or lag phase for this enzyme is dependent upon both calcium concentration and substrate interfacial surface area. At low concentrations (less then 50 muM) calcium ions affect the induction period but not the maximal rate of hydrolysis, whereas guinine predominantly affects the rate of hydrolysis by alterations in the surface charge carried by the substrate.

Calcium↗