Biomedical subjects
Publications and source records attributed to E A Hall.
Immobilized reagent phase flow injection analysis can be configured as discrete reagent cells upstream of the sensor element or as an integral reagent/transduction system (flow injection analysis-biosensor). The former approach has attracted greater attention because several assays can be assembled with greater versatility in reagent column units employing a single sensor, than can be co-immobilized on the surface of a transducer.
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The biosensor exploits the unique specificity of biological recognition events by coupling an enzyme, antibody or other biorecognition species to a transducing device. Interaction of the biocomponent with substrate or antigen is thus converted into a suitable quantitative output. The development of these biosensors is a multidisciplinary effort, exploiting many of the emerging semiconductor and optics technologies and integrating many traditional assay techniques. The impact of these biosensors is likely to be wide-ranging, with applications in medical and industrial environments as well as a variety of other fields.
This review introduces the multidisciplinary subject of biotechnology and the exploitation of the 'biomolecule'. The author describes practical applications of micro-organisms and biologically derived molecules. Some of these processes have been known for many years but recent developments have led to very rapid expansion of understanding and knowledge of the subject. Areas of the technology discussed include monoclonal antibodies, gene manipulation, enzymes, cell cultures, biosensors and biological processing products.
The role of electrode materials in the reduction of halothane and oxygen mixtures at rotating and stationary electrodes is considered. Halothane is found to be electroactive within the available electrode-potential range on silver and on gold. Double potential step experiments are considered in order to isolate the individual halothane and oxygen signals. A double integration, single potential step technique is evaluated for the quantitative simultaneous measurements of oxygen and halothane on gold. The influence of electrode purity is discussed in terms of a reaction mechanism and electrode output error.
Forty patients were selected to participate in a double-masked comparative study of the Seiko Plax 3 (P-3) and Varilux 2 progressive addition lenses. The study was designed to determine patient preference for either lens design. The patients wore each lens for 1 month. Following each period, a questionnaire relating to the patient's impressions of the lenses was completed. After both wearing periods, the patient's preference was determined. The results show that 89.7% of the patients preferred the Seiko lens over the Varilux. Further, 82.4% chose the Seiko lens and 44.1% chose the Varilux lens over their habitual multifocal design. The results of this study show that, in addition to a preference for the Seiko P-3 design, both progressive addition lenses are viable alternatives to the conventional multifocal lens.
Previous results have demonstrated that liver membranes possess two distinct lipoprotein receptors: a low density lipoprotein (LDL) receptor that binds lipoproteins containing either apolipoprotein (apo-) B or apo-E, and an apo-E-specific receptor that binds apo-E-containing lipoproteins, but not the apo-B-containing LDL. This study reports the isolation and purification of apo-B,E(LDL) and apo-E receptors from canine and human liver membranes. The receptors were solubilized with the zwitterionic detergent 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate and were partially purified by DEAE-cellulose chromatography. The apo-B,E(LDL) receptor was isolated by affinity chromatography on LDL-Sepharose. The apo-E receptor, which did not bind to the LDL-Sepharose column, was then purified by using an HDLc (cholesterol-induced high density lipoprotein)-Sepharose affinity column and an immunoaffinity column. Characterization of the receptors revealed that the hepatic apo-B,E(LDL) receptor is similar to the extrahepatic LDL receptor with an apparent Mr = 130,000 on non-reducing sodium dodecyl sulfate-polyacrylamide gels. The apo-E receptor was found to be distinct from the apo-B,E(LDL) receptor, with an apparent Mr = 56,000. The purified apo-E receptor displayed Ca2+-dependent binding to apo-E-containing lipoproteins and did not bind to LDL or chemically modified apo-E HDLc. Antibodies raised against the apo-B,E(LDL) receptor cross-reacted with the apo-E receptor. However, an antibody prepared against the apo-E receptor did not react with the apo-B,E(LDL) receptor. The apo-E receptor also differed from the apo-B,E(LDL) receptor in amino acid composition, indicating that the apo-E receptor and the apo-B,E(LDL) receptor are two distinct proteins. Immunoblot characterization with anti-apo-E receptor immunoglobulin G indicated that the apo-E receptor is present in the hepatic membranes of man, dogs, rats, and mice and is localized to the rat liver parenchymal cells.
Erythroid burst-forming units (BFU-E) from mouse bone marrow were grown for 7 days in agar or serum-free methylcellulose cultures in the presence or absence of erythropoietin (Ep) and/or interleukin 3 (IL-3). It was found that IL-3, even in the absence of serum and detectable Ep, was able to stimulate the full development of many erythroid bursts. This IL-3 effect was cell-dose dependent and did not appear to correlate with Ep dose. Spontaneous bursts and those stimulated by Ep only were rare and when seen were very small relative to those produced by IL-3 or IL-3 plus Ep. When addition of IL-3 or Ep to 7-day cultures was delayed, IL-3 but not Ep was shown to maintain BFU-E. No evidence was found by radioimmunoassay that Ep was produced or released in 7-day, "serum-free" cultures of bone marrow nor was Ep activity detected in culture media except those to which it had been added deliberately.
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Citrinin has an inhibitory effect on growth of T. pyriformis. Citrinin also caused a shift to smaller cell size, particularly at the higher concentrations (25, 50 and 100 mug/ml). The mycotoxin exerted only a marginal effect on the respiration of T. pyriformis; but citrinin (25 mug/ml) induced an inhibitory effect on DNA, RNA and protein content. The greatest decrease was in RNA, while smaller decreases in protein and DNA were observed. A bioassay employing T. pyriformis was determined; the lower limit of citrinin detection was between 1 and 5 mug/ml.
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1. The linkage between the polysaccharide and mucopeptide components of the cell wall of Lactobacillus casei is rapidly hydrolysed under mild acid-hydrolysis conditions. 2. The release of the polysaccharide is accompanied by the hydrolysis of an N-acetylhexosaminide linkage. The N-acetylhexosamine residue readily forms chromogen and it is concluded that it is substituted on C((3)) by the adjacent sugar. 3. Continued heating of the polysaccharide in acid results in a slower release of reactive N-acetylhexosamine due to the hydrolysis of glycosidic linkages within the polysaccharide. 4. After the linkage between the polysaccharide and mucopeptide has been hydrolysed, acid phosphatase will release approx. 40% of the total phosphorus as inorganic phosphate. 5. It is concluded that the polysaccharide component of the cell wall is joined through its reducing end group to a phosphate grouping in the mucopeptide.
1. The polysaccharide and mucopeptide components of the cell wall of Lactobacillus casei have been separated by mild conditions of acid hydrolysis. 2. Removal of the polysaccharide renders the mucopeptide susceptible to lysozyme. 3. The mucopeptide and polysaccharide components have been analysed and the results compared with those obtained previously. 4. The polysaccharides responsible for group specificity have a terminal reducing N-acetylgalactosamine residue substituted on C((3)) by the adjacent sugar; estimation of this component gave an indication of the molecular weight of the polysaccharides. 5. Evidence has been obtained for the presence of rhamnosyl-(1-->3)-N-acetylgalactosamine among the products of acid hydrolysis of the group B polysaccharide.
Immunologic and hematologic effects of continuous, chronic exposure of mice to ozone are reported. A consistent decrease was found in ability of spleen cells from exposed mice to engage in primary antibody formation. Results from an investigation of the possible presence of suppressor cells were inconclusive Separation of spleen cells into adherent and nonadherent populations revealed suggestive differences between normal and ozone-exposed mice. Among myelopoietic progenitors examined, CFU-S, CFU-GM, CFU-E, CFU-ME, and BFU-E, only the last two named were found to be altered after ozone exposure. The possible bases and implications of these findings are discussed.
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