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Morgan A, Holmes A. Solubility of rockwool fibres in vivo and the formation of pseudo-asbestos bodies. THE ANNALS OF OCCUPATIONAL HYGIENE 1984; 28:307-14. [PMID: 6508081 DOI: 10.1093/annhyg/28.3.307] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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302
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Morgan A, Holmes A. The distribution and characteristics of asbestos fibers in the lungs of Finnish anthophyllite mine-workers. ENVIRONMENTAL RESEARCH 1984; 33:62-75. [PMID: 6692815 DOI: 10.1016/0013-9351(84)90009-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Measurements of the concentrations and dimensions of uncoated and coated fibers in blocks of tissue taken at the periphery and elsewhere from slices of lungs obtained from two anthophyllite-mine workers are reported. A single block from the lung of a third worker was also analyzed. For the subject examined in most detail, the mean peripheral fiber concentration was greatest in the lower lobe. In the other subject there did not appear to be much variation in fiber concentration with distance from the periphery. The count median lengths of uncoated fibers ranged from about 8 to 12 micron and for coated fibers from 40 to 50 micron. It was apparent that dicing tissue samples, before hypochlorite digestion, led to fracture of the longer uncoated and coated fibers. The results are compared with similar measurements made on the lung of an insulation worker and reported previously.
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303
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Sykes SE, Morgan A, Moores SR, Holmes A, Davison W. Dose-dependent effects in the subacute response of the rat lung to quartz. I. The cellular response and the activity of lactate dehydrogenase in the airways. Exp Lung Res 1983; 5:229-43. [PMID: 6319111 DOI: 10.3109/01902148309061517] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The response of the rat lung to a range of doses of quartz at 50 and 100 days after its administration by intratracheal instillation was investigated by bronchopulmonary lavage. The effects on the numbers of polymorphonuclear leucocytes, lymphocytes and macrophages recovered are described. In addition, the size distribution of the recovered macrophages was followed and measurements of total numbers of macrophages in the lung were made using a radioactive tracer technique. Finally, the activity of the cytoplasmic enzyme, lactate dehydrogenase, in lavage fluid supernatants was recorded. There was a dose-dependent increase in the recovery of all three cell types and an increase in the total numbers of macrophages in the lungs which showed no signs of resolution over the 100 day period studied. Increasing levels of lactate dehydrogenase were also dose-dependent and well correlated with the numbers of polymorphs and lymphocytes recovered. The importance of this prolonged inflammatory reaction in relation to the fibrogenic action of quartz is discussed.
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304
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Sykes SE, Morgan A, Moores SR, Davison W, Beck J, Holmes A. The advantages and limitations of an in vivo test system for investigating the cytotoxicity and fibrogenicity of fibrous dusts. ENVIRONMENTAL HEALTH PERSPECTIVES 1983; 51:267-273. [PMID: 6315369 PMCID: PMC1569310 DOI: 10.1289/ehp.8351267] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The acute response of the rat lung to a range of fibrous materials has been investigated by bronchopulmonary lavage, at dose levels of 0.5 and 1.0 mg, 1 and 7 days after their administration by intratracheal instillation. The materials chosen for study included UICC chrysotile A, amosite, crocidolite and anthophyllite, and samples of S. African "long" amosite and glass fiber. In addition, the subacute response to 1, 2 and 3 mg of chrysotile and amosite has been studied at 50 and 100 days after instillation. In the acute phase at 1 day after instillation, the response to chrysotile was greater than that to any of the other materials, but by 7 days there was no gradation in the response to different dusts. In the subacute phase, cell recoveries were low, and it was not possible to assess the long-term cytotoxic or fibrogenic effects of amosite and chrysotile by analyses of lung washes, even though biochemical and histological methods indicated gross changes in lung pathology.
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305
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Sykes SE, Morgan A, Moores SR, Jones ST, Holmes A, Davison W. Evidence for a dose-dependent inflammatory response to quartz in the rat lung and its significance in early changes in collagen metabolism. ENVIRONMENTAL HEALTH PERSPECTIVES 1983; 51:141-146. [PMID: 6315354 PMCID: PMC1569287 DOI: 10.1289/ehp.8351141] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The response of the rat lung to a range of doses of quartz at 50 and 100 days after its administration by intratracheal instillation has been assessed by bronchopulmonary lavage. The effects on the number of polymorphonuclear leukocytes (PMN), lymphocytes and macrophages are described. In addition the concentrations of soluble protein and hydroxyproline and the activities of lactate dehydrogenase, PZ peptidase and collagenase in lavage fluid supernatants were measured and an assessment of the hydroxyproline content of recovered cells was made. Finally PZ peptidase and collagenase were assayed in PMN-enriched cell fractions and in samples obtained from short-term culture of recovered macrophages. There was a dose-dependent increase in the recovery of all three cell types, and in the amounts of lactate dehydrogenase, protein and hydroxyproline in lavage fluids, which showed no signs of resolution over the 100-day period studied. Measurements of PZ peptidase and collagenase suggested that the PMN, not the macrophages, are the major source of these degradative enzymes. The relevance of these findings with regard to the importance of PMN in quartz-induced fibrosis is discussed.
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306
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Demarco de Hormaeche R, Thornley MJ, Holmes A. Surface antigens of gonococci: correlation with virulence and serum resistance. JOURNAL OF GENERAL MICROBIOLOGY 1983; 129:1559-67. [PMID: 6413645 DOI: 10.1099/00221287-129-5-1559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Encapsulated and non-encapsulated variants of one strain of gonococcus were compared for their capacity to produce infection in chambers implanted subcutaneously in mice, for their reactions with specific antibody and for their precipitation with wheat germ agglutinin. Only the encapsulated variant could infect implanted chambers. Specific rabbit antiserum raised against the non-encapsulated variant killed both variants. Saline extracts and lipopolysaccharide preparations of the encapsulated variant differed from those of the non-encapsulated one in their reactions with wheat germ agglutinin and antibody in diffusion and electrophoresis tests. Preparations from infective encapsulated gonococci reacted with wheat germ agglutinin while those from the non-encapsulated variant did not. Immunodiffusion tests showed that lipopolysaccharides from both variants share a common antigenic determinant, but saline extracts and lipopolysaccharides from encapsulated gonococci possess an additional determinant. The significance of these findings is discussed.
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307
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Morgan A, Holmes A. Distribution and characteristics of amphibole asbestos fibres, measured with the light microscope, in the left lung of an insulation worker. BRITISH JOURNAL OF INDUSTRIAL MEDICINE 1983; 40:45-50. [PMID: 6824599 PMCID: PMC1009116 DOI: 10.1136/oem.40.1.45] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Concentrations of uncoated and coated amphibole fibres were measured postmortem in samples taken from the periphery of both upper and lower lobes of the left lung of an insulation worker. Similar measurements were made on a more limited range of samples from elsewhere in the lung and on a hilar lymph node. The mean concentration of uncoated fibres in the upper lobe was twice that in the lower. Significant differences were observed in the mean concentration of uncoated fibres in different regions of the periphery, the diaphragmatic region having the lowest value. Variations in the concentrations of both uncoated and coated fibres in the costal region of the lower lobe may have been related to the effect of rib structures on ventilation. Concentrations of fibrous and non-fibrous dust were well correlated in the peripheral samples. The length distributions of uncoated and coated fibres were also measured and differences detected in fibres from the various regions of the lung. This work emphasises the care required in sampling lung tissue in order to obtain representative material for the determination of fibre concentration.
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308
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Holmes A, Morgan A, Davison W. Formation of pseudo-asbestos bodies on sized glass fibres in the hamster lung. THE ANNALS OF OCCUPATIONAL HYGIENE 1983; 27:301-13. [PMID: 6638764 DOI: 10.1093/annhyg/27.3.301] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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309
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Morgan A, Holmes A, Davison W. Clearance of sized glass fibres from the rat lung and their solubility in vivo. THE ANNALS OF OCCUPATIONAL HYGIENE 1982; 25:317-31. [PMID: 7181257 DOI: 10.1093/annhyg/25.3.317] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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310
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Holmes A. Survey of critical care nursing practice. Part V. Type of equipment and responsibilities of personnel with regard to equipment. Heart Lung 1982; 11:242-7. [PMID: 6918390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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311
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Morgan A, Holmes A. Concentrations and characteristics of amphibole fibres in the lungs of workers exposed to crocidolite in the British gas-mask factories, and elsewhere, during the second world war. BRITISH JOURNAL OF INDUSTRIAL MEDICINE 1982; 39:62-9. [PMID: 7066222 PMCID: PMC1008929 DOI: 10.1136/oem.39.1.62] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Concentrations and length distributions of uncoated and coated amphibole fibres in the lungs of 27 workers at the Leyland, Nottingham, and Blackburn gas-mask factories were measured after death with the light microscope using the membrane filter technique. Measurements were also made on a worker exposed to crocidolite at the Chemical Defence Experimental Establishment, Porton, and on three miners from the Wittenoom mine in Western Australia where the crocidolite used in the manufacture of military respirators is reputed to have originated. In selected cases, fibre concentrations and dimensions were also measured with the electron microscope. All but two subjects died with a mesothelial tumour. Fibre concentrations ranged from 7 x 10(4) to almost 10(9) fibres/g dry weight. There appeared to be no relation between latent period and fibre concentration. The significance of the wide range of fibre concentrations which was associated with the development of mesothelial tumours is discussed and also the relation between the relative frequency and dimensions of uncoated and coated fibres.
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312
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Sykes SE, Morgan A, Evans JC, Evans N, Holmes A, Moores SR. Use of an in vivo test system to investigate the acute and sub-acute responses of the rat lung to mineral dusts. THE ANNALS OF OCCUPATIONAL HYGIENE 1982; 26:593-605. [PMID: 7181291 DOI: 10.1093/annhyg/26.5.593] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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313
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Meyer RF, Nicolaides ED, Tinney FJ, Lunney EA, Holmes A, Hoefle ML, Smith RD, Essenburg AD, Kaplan HR, Almquist RG. Novel synthesis of (S)-1-[5-(benzoylamino)-1,4-dioxo-6-phenylhexyl]-L-proline and analogues: potent angiotensin converting enzyme inhibitors. J Med Chem 1981; 24:964-9. [PMID: 6173481 DOI: 10.1021/jm00140a010] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
A new approach was developed for the synthesis of (S)-1-[5-(benzoylamino)-1,4-dioxo-6-phenylhexyl]-L-proline (1) and 23 analogues. The delta-(acylamino)-gamma-keto acid intermediates were obtained by a modified Dakin--West reaction using 3-carbomethoxypropionyl chloride. Acylation of L-proline and recrystallization of the mixture of diastereomers gave the optically pure title compound in three reaction steps. The in vitro angiotensin converting enzyme (ACE) inhibitory activity of 1 was confirmed. Some of the novel analogues (6, 11, 13, and 17) were also found to be potent inhibitors of ACE in vitro with an IC50 of 1.4-8.8 x 10(-9) M (IC50 for captopril = 0.9 x 10(-8) M). In vivo these compounds (6, 11, 17, and 18) were much less active than captopril, especially by the oral route. Against angiotensin I (AI) challenge in normotensive conscious rats, 1 and 6 produced less than 50% inhibition at 30 mg/kg po but 57 to 82% inhibition at 3 mg/kg iv. Inhibition by both routes lasted less than 1 h. In renal hypertensive rats, 1 and 15 of its analogues failed to produce significant blood pressure lowering effects, in contrast to the marked effects of captopril. Near maximum inhibition of AI was achieved by continuous intravenous infusions of 1 and 20, suggesting that limited oral activity may by due to degradation and/or clearance.
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314
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Abstract
Our purpose was to investigate the influence of acoustic radiation produced by bone vibrators at 4000 Hz on bone conduction (BC) testing. In one study, BC thresholds were obtained with a Radioear B-70A, B-71, and B-72 vibrator when the subject's ear canal was unoccluded and occluded. In another study, probe-tube microphone measurements were made just inside the entrance to the ear canal for each vibrator and for an air conduction source at comparable sensation levels. Results of both studies were interpreted to indicate that the B-70A and B-71 produced minimal acoustic radiation. However, the B-72 was found to have excessive acoustic radiation which would be sufficient to influence BC thresholds and produce an invalid high-frequency air-bone gap.
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315
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Taylor GA, Peacock M, Pelc B, Brown W, Holmes A. Purification of plasma vitamin D metabolites for radioimmunoassay. Clin Chim Acta 1980; 108:239-46. [PMID: 6969637 DOI: 10.1016/0009-8981(80)90010-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The ability of four solvent systems to extract tritiated 25-hydroxy vitamin D3, 24,25-dihydroxy vitamin D3, 25,26-dihydroxy vitamin D3 and 1 alpha, 25-dihydroxy vitamin D3 from plasma was compared. Diethyl ether gave the highest yield of metabolites and lowest yield of "lipid" materials, the dihydroxylated metabolites were more readily extracted than 25-hydroxy vitamin D3. Following extraction with ether the vitamin D metabolites could be separated, without prior purification, on a 6.2 mm X 250 mm Zorbax-Sil high pressure liquid chromatography (HPLC) column, a simplification of previous methods. Plasma 1 alpha, 25-dihydroxy vitamin D levels measured after purification by this method were not significantly different from those obtained by an established, more complex method.
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316
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Morgan A, Black A, Evans N, Holmes A, Pritchard JN. Deposition of sized glass fibres in the respiratory tract of the rat. THE ANNALS OF OCCUPATIONAL HYGIENE 1980; 23:353-66. [PMID: 7258930 DOI: 10.1093/annhyg/23.4.353] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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317
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Juhl YH, Alpert MY, Holmes A, Perrizo CH, Roberts RW, Thornton LK. Semiautomated Method for Analysis of Nitroglycerin in Sublingual Tablets: Collaborative Study. J AOAC Int 1980. [DOI: 10.1093/jaoac/63.4.696] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
This method is a semiautomated version of the current USP XX method for content uniformity testing of nitroglycerin tablets. Nitroglycerin is hydrolyzed to nitrite in aqueous alkali. The nitrite thus formed diazotizes procaine, which then is coupled with Bratton-Marshall reagent; the absorbance of the resultant color is read at 550 nm. Six collaborators were supplied with 6 composites of sublingual tablets, representing 3 different dosage levels. Results agreed with those obtained by the author using the USP composite assay method. The coefficients of variation ranged from 0.20 to 0.70%. The method is sensitive enough for individual tablet assays (0.15 mg nitroglycerin). The method has been adopted as official first action.
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318
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Holmes A, Morgan A. Clearance of anthophyllite fibers from the rat lung and the formation of asbestos bodies. ENVIRONMENTAL RESEARCH 1980; 22:13-21. [PMID: 7418671 DOI: 10.1016/0013-9351(80)90114-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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319
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Morgan A, Moores SR, Holmes A, Evans JC, Evans NH, Black A. The effect of quartz, administered by intratracheal instillation, on the rat lung. I. The cellular response. ENVIRONMENTAL RESEARCH 1980; 22:1-12. [PMID: 6252009 DOI: 10.1016/0013-9351(80)90113-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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320
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Morgan A, Holmes A. Concentrations and dimensions of coated and uncoated asbestos fibres in the human lung. BRITISH JOURNAL OF INDUSTRIAL MEDICINE 1980; 37:25-32. [PMID: 7370190 PMCID: PMC1008641 DOI: 10.1136/oem.37.1.25] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Concentrations and length distributions of uncoated and coated amphibole-type fibres in samples of human lung taken at necropsy were measured by optical microscopy using the membrane filter technique that enables fibres with diameters down to about 0.2 micron to be detected. The subjects included 10 who died with mesothelial tumours, three with lung cancer, and eight of other causes. Measurements of fibre concentrations are compared with those of other workers. It can be deduced from the length distributions that fibres less than 5 microns long are cleared from the lung more efficiently than longer ones. The clearance of short fibres appears to be inhibited in subjects with asbestosis, however. The length distributions of uncoated and coated fibres were dissimilar. In general, few fibres less than 10 microns in length were coated and few greater than 40 microns in length were uncoated. The probability of a fibre of given length, however, becoming coated varied considerably from subject to subject. Possible reasons for this are discussed.
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321
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Holmes A, Carlisle I. Axial muscle and myocutaneous flaps: a recent concept in wound closure. THE AUSTRALIAN AND NEW ZEALAND JOURNAL OF SURGERY 1979; 49:531-45. [PMID: 292401 DOI: 10.1111/j.1445-2197.1979.tb05870.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Until the last decade, the greatest advances in reconstructive surgery have been skin grafting and the advent of pedicle flaps. More recently a new understanding of the discrete vascular anatomy of the skin and other composite tissues has enabled the transfer of these tissues with far more reliability, either locally or--using microvascular techniques--to a distance. The axial and random concept of blood supply of flaps will be outlined. A brief historical background of the development of axial flaps is included. A synopsis of the anatomy, uses and limitations of the commonly used and proven muscle and myocutaneous flaps in our experience is reported. In the final discussion, a new and simple classification of wound closure is proposed which encompasses all the recent developments in this field.
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322
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Drysdale HC, Emerson PM, Holmes A. An improved method for the measurement of red cell survival using non-radioactive chromium. J Clin Pathol 1979; 32:655-9. [PMID: 500836 PMCID: PMC1145771 DOI: 10.1136/jcp.32.7.655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
An improved technique for the measurement of red cell survival is described in which non-radioactive 50Cr is used in patients for whom radioactive labels are not advisable. The 50Cr was measured by neutron activation analysis using a high resolution germanium (lithium) diode gamma-ray spectrometer. In adult controls, the values obtained were in the range accepted as normal for the 51Cr method, and double labelling experiments showed close agreement. The application of this technique to the measurement of red cell survival in pregnant women suspected of having haemolytic anemia is described.
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323
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Tomasko MG, Doose LR, Palmer J, Holmes A, Wolfe W, Castillo ND, Smith PH. Preliminary Results of the Solar Flux Radiometer Experiment Aboard the Pioneer Venus Multiprobe Mission. Science 1979; 203:795-7. [PMID: 17833001 DOI: 10.1126/science.203.4382.795] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The solar flux radiometer aboard the Pioneer Venus large probe operated successfully during its descent through the atmosphere of Venus. Upward, downward, and net fluxes from 0.4 to 1.0 micrometers were obtained at more than 390 levels between 185 millibars (at an altitude of approximately 61 kilometers) and the surface. Fluxes from 0.4 to 1.8 micrometers were also obtained between 185 millibars and about the level at which the pressure was 2 atmospheres. Data from 80 to 185 millibars should be available after additional decoding by the Deep Space Network. Upward and downward intensities in a narrower band from 0.59 to 0.66 micrometers were also obtained throughout the descent in order to constrain cloud properties. The measurements indicate three cloud regions above the 1.3-atmosphere level (at an altitude of approximately 49 kilometers) and a clear atmosphere beneath that level. At the 67 degrees solar zenith of the probe entry site, some 15 watts per square meter are absorbed at the surface by a dark ground, which implies that about 2 percent of the solar energy incident on the planet is absorbed at the ground.
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324
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Morgan A, Talbot RJ, Holmes A. Significance of fibre length in the clearance of asbestos fibres from the lung. BRITISH JOURNAL OF INDUSTRIAL MEDICINE 1978; 35:146-153. [PMID: 656339 PMCID: PMC1008368 DOI: 10.1136/oem.35.2.146] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Rats were exposed by inhalation to radioactive anthophyllite asbestos. Animals were then killed serially over a period of 205 days and the fibre content of the lungs measured radiometrically. The lungs were subjected to selective bronchopulmonary lavage and the mean fibre content determined of free cells recovered from the alveolar spaces. The length distributions of fibres recovered from the lungs by lavage, and of those remaining in the lungs following lavage, were measured. Short (less than 5 micrometer) fibres are cleared from the lung via the conducting airways more efficiently than longer fibres and fibres exceeding 50 micrometer in length are not removed from the lungs by this route. Although fibres of about 200 micrometer in length were present in all the lungs examined, the longest which could be recovered by lavage, once fibre deposited in the airways had been cleared, was only about 100 micrometer decreasing to 60-70 micrometer after 205 days. It is suggested that long fibres are more liable than short to penetrate the alveolar wall as they tend to bridge the alveolar ducts and alveoli.
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325
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Morgan A, Davies P, Wagner JC, Berry G, Holmes A. The biological effects of magnesium-leached chrysotile asbestos. BRITISH JOURNAL OF EXPERIMENTAL PATHOLOGY 1977; 58:465-73. [PMID: 588440 PMCID: PMC2041255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Chrysotile asbestos was leached in N hydrochloric acid for varying times to produce a range of magnesium-depleted samples. The protein adsorptive capacity, the haemolytic activity, and the capacity to cause selective release of acid hydrolases from macrophages were measured for the various samples in vitro. The carcinogenicity of the same materials was determined following intrapleural inoculation in rats. The adsorptive capacity for albumin decreased linearly with magnesium removal. The haemolytic activity also declined until about half the magnesium had been removed, after which there was little further change. The selective release of acid hydrolases from macrophages in culture increased up to the point at which half the magnesium had been removed but by 90% depletion had declined rapidly. The carcinogenicity of 50% -depleted chrysotile was similar to that of intact, but at 90% depletion the incidence of mesothelial tumours had fallen considerably. There was no evidence that the leached samples fragmented more than the unleached in vivo.
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