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Biomedical subjects

J F Kennedy

Publications and source records attributed to J F Kennedy.

At least 19 recordsLinked to original sources
PubMed2003

Isolation of a trypsin inhibitor from Echinodorus paniculatus seeds by affinity chromatography on immobilized Cratylia mollis isolectins.

A highly purified trypsin inhibitor was obtained from Echinodorus paniculatus when an extract prepared from E. paniculatus seed flour (25 gl(-1), with 0.1 M ammonium acetate buffer, pH 8.3, under agitation for 6 min at 28 degrees C) was chromatographed on Sephadex G-25 (12 mlh(-1)), followed by affinity chromatography on immobilized Cratylia mollis isolectins (Cra Iso 1,2,3-Sepharose). The column chromatography was performed at 24 degrees C; the matrix was washed (30 mlh(-1)) with 0.1 M sodium phosphate buffer, pH 7.4 or with the same buffer containing 0.2 M glucose, followed by application of inhibitor sample and elution with 0.015 M sodium borate buffer, pH 7.4, or 1.0 M NaCl. A purified fraction of inhibitor was obtained by gel filtration chromatography (GF-450/HPLC column). Trypsin inhibitory activity was eliminated when the inhibitor was treated with metaperiodate showing that the carbohydrate moiety was important for trypsin inhibition. Binding of inhibitor was also evaluated on immobilized concanavalin A (Con A-Sepharose) using previously described chromatographic conditions with results similar to Cra Iso 1,2,3-Sepharose chromatography.

Alismataceae↗
PubMed2002

Advanced wound care materials: developing an alginate fibre containing branan ferulate.

OBJECTIVE: This laboratory-based study set out to establish whether branan ferulate--a polysaccharide compound available in gels such as as Sterigel (SSL International, UK)--could be successfully added to the fibre of an alginate dressing to provide a superior wound-care dressing. METHOD: A wet extruder (Howden Engineering Services, UK) was used to produce the fibres. Researchers examined the effect of spinning-bath calcium chloride concentration (used as the coagulant in the fibre-spinning process) on the tensile and absorption properties of alginate fibres containing 25% w/w branan ferulate. Sodium alginate and branan ferulate were separately dissolved in de-ionised water and then stirred together to make up a 5% dope solution. The dope was then forced through a spinneret and into the calcium chloride bath, where fibres were precipitated and then carried over the first set of rollers. The fibres were washed in the next bath and drawn at different rates to enhance their tensile properties. At the 'winding-up' stage the filaments were either passed over a contact heater and into a furnace (dry pick-up) or transferred into acetone baths of increasing concentrations of 50, 80 and 100% aqueous acetate to remove the water (wet pick-up). The moisture content of standard alginate fibres and those with branan ferulate were measured and compared. Breaking load, tenacity and breaking extension, and the quantity of branan ferulate in the fibres were also measured. The process was repeated four times, using different strengths of calcium chloride. Using various draw ratios, the effects of liquid uptake were measured using water, saline and a solution called A (to mimic human blood and exudate-type fluids). RESULTS: Out of the four calcium chloride concentrations used, 1% concentration appeared to give the highest and most conclusive results for fibre-breaking load, tenacity and breaking extension. CONCLUSION: A 1% w/v concentration of calcium chloride provides the optimum conditions for achieving suitably strong fibres with adequate absorption capacity, while allowing the least branan ferulate loss during wash and post-production treatments. In a laboratory setting the product showed promise. Research is now needed in a clinical setting and for comparison with existing wound-care products.

Alginates↗
PubMed2000

Immobilization of pneumococcal polysaccharide vaccine on silicon oxide wafer for an acoustical biosensor.

One the most important aspects of a biosensor is related to immobilization and maintenance of specific reference compounds on sensing surfaces. A method for the immobilization of polysaccharides to a silicon oxide surface intended for Surface Acoustical Waves (SAW) sensors is described. Silicon oxide is a hydrophobic inorganic support used for the fabrication of many electronic devices. The pneumococcal polysaccharide (PPS) vaccine is immobilized via Protein A after pre-treatment of the surface with hydrochloric acid. The effects of non-specific binding are discussed. The results indicate that the immobilization of PPS via Protein A increases the sensitivity of detecting Streptococcus pneumoniae antibodies in human sera and offers greater reproducibility of response compared with ELISA methods. The principles of this technique are simple and are applicable to the immobilization of many capsular polysaccharides.

Acoustics↗
PubMed2000

Public involvement.

Explore the source record for details and available documents.

Community Health Planning↗
PubMed1999

Carbon dioxide transport by proteic and facilitated transport membranes.

Membrane separation of gases is governed by the permeability of each species across the membrane. The ratio of permeabilities yields the selectivity. Use of certain organic carriers in facilitated transport membranes and the CO2 converting enzyme carbonic anhydrase (CA) in proteic and facilitated transport membranes allows a dramatic increase in CO2 selectivity over other gases. CA has a low Km (9 mM), which we predicted would allow it to scavenge CO2 to very low partial pressures. Our goal was to determine if CA could remove CO2 from an environment at levels of 0.1% or less. Prior measurements of CO2 transport across thin supported liquid membranes showed that addition of CA enhanced CO2 flux by 3- to 100-fold. Proteic films use bifunctional reagents (e.g., glutaraldehyde) to cross-link the enzyme forming a gel. Bovine serum albumin (BSA) is often added for structural stability. Using such a preparation we examined the ability of proteic films to improve CO2 selectivity and to scavenge CO2 from a mixed gas stream. Proof-of-concept results, measured by mass spectrometry, showed a fivefold improvement in CO2 capture rate with maximal improvement at CO2 values of 1% partial pressure difference in the presence of 0 atm absolute difference. At 0.1% CO2 the membrane exhibited a 76% improvement over controls. At 0.3% CO2 the improvement is about threefold. CA proteic membranes exhibit selectivity for CO2 over oxygen and nitrogen in excess of three orders of magnitude. A CA-based proteic or facilitated transport membrane should readily achieve CO2 partial pressures of 0.05% under CELSS conditions. In addition to proteic membranes we are exploring direct immobilization of engineered CA to ultra-high-permeability teflon membranes. Site-directed mutagenesis was used to add functional groups while retaining full enzymatic activity. These results provide a basis for development of far more efficient CO2 capture proteic and facilitated transport membranes with increased selectivity to values closer to 100-fold at 1% CO2. The result will be CO2 selectivity at 0.1% on the order of 400-fold. These results exceed those obtained with other technologies.

Biological Transport↗
PubMed1997

Enteral feeding for the critically ill patient.

This article challenges nurses to examine their practice and procedure when establishing enteral feeding. The author suggests that discontinuation for 'complications' such as diarrhoea may not be appropriate, and recommends that nurses take more responsibility for patient nutrition.

Critical Care↗
PubMed1997

Rheological studies on the solubilization by the surfactant SDS of complexes between three acidic polysaccharides and an organic base chloride.

Developments in the solubilization of complexes between the cationic polymer, poly(hexamethylenebiguanidinium chloride) (PHMBH+Cl-) and acidic polysaccharides are reported. It was discovered that the anionic detergent sodium dodecyl sulphate (SDS) is an excellent solubilizer for these complexes, enabling several multi-component systems to be studied. SDS itself was shown to interact with PHMBH+Cl- to form a highly viscous solution. Maximum viscosity was obtained with a SDS:PHMBH+Cl- molar ratio of 15.6. SDS:PHMBH+Cl- at this ratio served as a good solubilizer for the acidic polysaccharides (sodium alginate, sodium carboxymethyl cellulose, and xanthan), forming highly viscous fluids. The effect of temperature on the viscosity of these solutions was also examined.

Alkalies↗
PubMed1996

Key strategic challenges facing purchasers of health care--a Scottish perspective.

This paper describes the key strategic challenges facing a purchaser of health care services in central Scotland. The paper describes a number of key issues including influencing the health of the local population, the financial constraints, the development of alliances and the involvement of service users in planning. It highlights the importance of organizational development and the management of the external environment. Long-term challenges associated with the purchase of health care are suggested and the paper concludes that achieving health status targets and the desires of the local population could well conflict. It suggests that health boards/authorities will need to enhance their planning and developmental work for the future.

Contract Services↗
PubMed1996

Kinetic analysis of ethanol production from glucose fermentation by yeast cells immobilized onto ceramic supports.

Porous ceramic supports have been developed and utilized for the immobilization of yeast cells to produce ethanol by the fermentation of glucose. The relationship between the porous structure of the ceramic support and the quantity of yeast cells immobilized and the production of ethanol by the fermentation have been investigated. A comparison of the properties of the ceramic supports with those of a calcium alginate gel indicated that the ceramics are the better of the two types of material and have potential for industrial application.

Absorption↗
PubMed1996

Glycoproteins: a consideration of the potential problems and their solutions with respect to purification and characterisation.

Glycoproteins, as a class of biomolecules, present a number of differences in structure and function from non-glycosylated proteins. This makes their purification and characterisation a potentially daunting prospect. This article provides a brief summary of the occurrence, structure and composition of glycoproteins and the main areas where these factors may complicate the purification and characterisation process. There follows a review of the range of techniques available, an insight into the choices of ways forward in considering glycoprotein purification and characterisation. Appropriate prominence is given to lectins; their application to the purification, identification and characterisation of glycoproteins, and the major contribution they have made to the study of this class of biomolecules.

Animals↗
PubMed1995

High-alkaline protease from Bacillus PB92 entrapped in calcium alginate gel. Physicochemical and microscopic studies.

High-alkaline protease (HAP) has been entrapped in Manugel DMB (an alginate gel) and assayed with two sizes and types of substrates: neutral protein casein and synthetic chromogenic tripeptide substrate, Z-Gly-Pro-Cit-PNA. Increasing the concentration of calcium chloride used for capsule formation decreased the measured enzyme activity with both substrates. Capsules were found to be stable in water for long periods of time, but they dissolved in both phosphate and carbonate-bicarbonate buffers. The pH vs activity profiles of encapsulated enzyme showed pH optima between 10 and 11 with both substrates. The calcium alginate matrix surrounding the enzyme was quite effective in stabilizing the enzyme at 20-25 degrees C and even more so at 4 degrees C. Enzyme stability at 50 degrees C was quite impressive, some enzyme activity being evident even after remaining for 1 wk at this temperature in water. Increasing concentrations of sodium dodecyl sulfate (SDS) were also found to inhibit the protease progressively, whereas a polyhexamethylene biguanidium chloride (PHMBH+Cl-) and SDS:PHMBH+Cl- combination showed the opposite effect. Optical microscopy, especially polarized light microscopy, provided a sensitive physical means of ascertaining some of the structural properties (sphericity, disorganization or organization, distinct layer enveloping the capsules, intensity of the maltese cross) of the capsules with and without enzyme before and after different chemical treatments and the presence or absence of the substrate.

Alginates↗
PubMed1995

Perspectives for biophysicochemical modifications of enzymes.

This article reviews the strategies and successes of modifying enzymes by means of biophysicochemical transformations. By judicious choice of methods, it has been possible to modify enzymes through physical interactions, chemical reactions and/or mutagenesis to alter a very wide range of properties ranging from stability and solubility on the one hand to catalytic activity and selectivity on the other.

Antibody Formation↗
PubMed1995

A model study on rate of degradation of L-ascorbic acid during processing using home-produced juice concentrates.

The rate of degradation of L-ascorbic acid in solution has been investigated under varying conditions, such as temperature, level of dissolved oxygen, pH, amino acids, sugars and processing conditions. Changes in pH between pH 1.5 and 7.0 accelerate L-ascorbic acid degradation. The most important factor that determines its stability is storage temperature, on which the rate of degradation of L-ascorbic acid is directly dependent. Similarly, the deleterious effect of variables such as oxygen and pH are influenced by temperature. Therefore, low temperature storage is imperative in order to regard L-ascorbic acid delay. A definite role of amino acids in L-ascorbic acid degradation has not been identified.

Amino Acids↗
PubMed1994

Expression of the merozoite surface protein gp195 in vaccinia virus.

The DNA sequence coding for the merozoite protein gp195 was inserted into the vaccinia virus expression plasmid pvHAX31. This recombinant plasmid was used to integrate the gp195 DNA into the vaccinia virus genome by homologous recombination. The resulting chimeric virus was tested for gp195 expression in CV-1 cells by Western blotting. The virus that gave positive results was then grown on a large scale and used to infect rabbits. The animal antibody response towards gp195 was analysed in detail. The possibility of using gp195 as a component in a multivalent malaria vaccine is discussed.

Animals↗
PubMed1994

Immobilization of carbohydrases on epoxide-, isocyanate-, acid chloride-, and carboxylic acid-activated plastic supports.

Methods for the covalent immobilization of alpha-amylase and glucoamylase on to epoxide-, isocyanate-, acid chloride-, and carboxylic acid-activated plastic supports have been optimized. The effects of the following parameters have been examined: coupling time, pH, and temperature; availability of the free essential reacting groups on the supports; porosity of the supports; and enzyme loading. Properties of the immobilized enzymes, such as coupled activity and operational stability were assessed.

Acids↗