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Biomedical subjects

R Burrows

Publications and source records attributed to R Burrows.

At least 19 recordsLinked to original sources
PubMed2005

Effect of glycemic index on whole-body substrate oxidation in obese women.

BACKGROUND: Glycemic index is hypothesized to determine fuel partitioning through serum plasma insulin modifications induced by dietary carbohydrates, thereby modulating fat accretion or oxidation. OBJECTIVE: To assess the glycemic effects on postprandial fuel oxidation and blood response. DESIGN: In all, 12 obese women were fed on a randomized crossover design with two test meals (breakfast+lunch). High- or low-glycemic meals were provided on separate days. Energy intake on high-glycemic meal was 7758+/-148 kJ and for low-glycemic meal was 7806+/-179 kJ. Carbohydrates supplied were 273+/-5 and 275+/-6 g, respectively. Macronutrient distribution was 55% carbohydrates, 30% fat and 15% protein. Fuel oxidation was measured continuously in a respiratory chamber for 10 h. Serum glucose, free fatty acids (FFA), insulin and glucagon samples were taken for 5 h after breakfast. RESULTS: Glucose AUC changed significantly in response to different glycemic breakfast. Low- vs high-glycemic breakfast was 211+/-84 and 379+/-164 mmol/l (P<0.05). Similarly, insulin changed from 94+/-37 and 170+/-87 nmol/l (P<0.05), respectively. The rate of increment for serum glucose and insulin reached by the high- vs low-glycemic meal was 1.8 times more with the high-glycemic breakfast. Serum FFA were similarly suppressed by both meal types by 3 h after meal intake, but then raised significantly more with the low-glycemic meal by the fourth and fifth hour (P<0.05). Plasma glucagon did not show a significant variation with glycemic index. Carbohydrate and fat oxidation was not modified by glycemic meal characteristics, being virtually the same for low- vs high-glycemic comparisons in the 5 h following breakfast and lunch (P=NS). CONCLUSION: This study demonstrates that dietary glycemic characteristics were unable to modify fuel partitioning in sedentary obese women.

Adult↗
PubMed2003

The utilisation of engineered invert traps in the management of near bed solids in sewer networks.

Large existing sewers are considerable assets which wastewater utilities will require to operate for the foreseeable future to maintain health and the quality of life in cities. Despite their existence for more than a century there is surprisingly little guidance available to manage these systems to minimise problems associated with in-sewer solids. A joint study has been undertaken in the UK, to refine and utilise new knowledge gained from field data, laboratory results and Computational Fluid Dynamics (CFD) simulations to devise cost beneficial engineering tools for the application of small invert traps to localise the deposition of sediments in sewers at accessible points for collection. New guidance has been produced for trap siting and this has been linked to a risk-cost-effectiveness assessment procedure to enable system operators to approach in-sewer sediment management pro-actively rather than reactively as currently happens.

Cities↗
PubMed2002

Erosion mechanisms in combined sewers and the potential for pollutant release to receiving waters and water treatment plants.

The problems associated with solids in sewerage systems result in common difficulties such as blockages and flooding and the subsequent maintenance requirements have been well documented. Concerns regarding pollutant release have also been demonstrated, with the contribution from in-sewer solids to the quality of the flow during a storm event being especially significant. These events known as "foul flushes" in combined sewers typically occur in the initial period of storm flows, when the concentration of suspended sediments and other pollutants are significantly higher than at other times. Traditionally impacts from these events have been related to the suspended solids phase of the flow passing through a CSO structure. It is now apparent that much of the suspended load originates from solids eroded from the bed. The "near bed solids" which are re-entrained into the flow, together with solids eroded from the bulk bed, account for large changes in the suspended sediment concentration under time varying flow conditions. The influence of these eroded solids and their potential impact on receiving waters and treatment plants will be reviewed using data obtained from field studies carried out in the main Dundee interceptor sewer in Scotland. This paper describes some of the methods employed to investigate the characteristics of the pollutants associated with solids erosion in combined sewers.

Equipment Failure↗
PubMed2001

A question of care...

Explore the source record for details and available documents.

General Practice, Dental↗
PubMed2001

Novel boom/skirt systems for improvement of water quality in estuarial impoundments subject to saline influx.

The recent popularity of esturial barrage construction in the UK has been driven largely by commercial and amenity interests arising from the need to rehabilitate tracts of derelict urban land. Formation of a permanent water body to replace the tidal regime hides unsightly mud banks and facilities ready access for water based recreation. Unfortunately, in most cases, and presumably arising from upstream extreme flood risk assessment, the barrier is designed to overtop under the highest (spring) tidal peaks so allowing a substantial influx of heavier saltwater into the impoundment on a regular basis. This might well substantially exceed influx via any navigational lock operations. The problem created by the salt water is that its greater density causes stratification in the impounded water body. In times of low freshwater flow little mixing takes place and the normal action of the wind, in circulating and aerating the water body, will only extend within the lighter and often thin surface freshwater layer. The consequence is that little reoxygenation of the lower layers takes place leading to depressed dissolved oxygen levels and possible anoxia. Sluice provision in the barrage may be ineffective in expelling the saline layers, so this water remains near stagnant and deteriorates in quality due to sediment oxygen demands until a major fluvial flood, or new saline influx, is able to effectively mix the waters. Conventional continuous surface releases through fish pass and/or by crest overspill ensure the preferential release of the freshwater rather than the problematic saltwater. Retrofitting of novel low cost floating boom/skirt baffle system is proposed here for alleviation of the problem.

Animals↗
PubMed2001

Marine-based waste stabilisation ponds: an evaluation of the hydraulic viability.

Marine-Based Waste Stabilisation Ponds, formed by floating boom/skirt curtain enclosures anchored in sheltered waters, have recently been proposed for provision of low-cost effluent treatment facilities where land availability is limited in rapidly expanding coastal cities in the Third World. This paper outlines findings from a viability assessment, which drew on a preliminary site evaluation and baseline environmental survey (for a site in sheltered waters in the Far East), laboratory studies involving scale model tests in wave/wind/current flumes, and a structural and design loading study. It focuses on hydraulic and hydrodynamic considerations and reports the study's conclusions.

Industrial Waste↗
PubMed2001

[Biological, familial and metabolic characteristics of infantile and juvenile obesity].

BACKGROUND: Obesity is the most prevalent nutritional disease in people of less than 20 years old. AIM: To report biological, familial and metabolic characteristics in obese children. PATIENTS AND METHODS: A retrospective review of 187 children seen at obesity clinics and that had a complete metabolic study. RESULTS: Ninety five prepuberal and 92 puberal children, aged 8.7 +/- 2.2 and 12.6 +/- 2.2 years old respectively, were studied. Body mass index was over 4 standard deviations in 48.4% of prepuberal children and in 39.1% of puberal children. Paternal obesity was twice more prevalent (30.2%) than in the general population. The daily caloric intake and basal metabolic rate (BMR) were within the normal range; nevertheless there was a positive caloric balance due to minimal physical activity. The mean daily fat intake was normal (26.4 +/- 8.5 and 25.3 +/- 9.1% of total calories in prepuberal and puberal children respectively). The daily fiber intake was under 70% of recommendation. The total cholesterol was over 200 mg/dl in 26.6 and 23.9% of prepuberal and puberal children. LDL cholesterol was over 130 mg/dl in 27.3 and 26.6% and triacylglycerol was over 150 mg/dl in 16.9 and 25% of prepuberal and puberal children respectively. Basal serum insulin was over 20 uIU/ml in 27.7 and 42.2% of prepuberal and puberal children, respectively. Post glucose serum insulin was over 60 uIU/ml in 40 and 63% of prepuberal and puberal children, respectively. CONCLUSIONS: Infantile and juvenile obesity is a chronic disease with a high incidence of metabolic alterations.

Adolescent↗
PubMed2000

Safety of withholding heparin in pregnant women with a history of venous thromboembolism. Recurrence of Clot in This Pregnancy Study Group.

BACKGROUND: Women with a history of venous thromboembolism may be at increased risk for venous thromboembolic events during pregnancy. In these women, the decision to give or withhold heparin in the antepartum period is controversial, because accurate estimates of the frequency of recurrent thromboembolic events if antepartum heparin is withheld are not available. METHODS: We prospectively studied 125 pregnant women with a single previous episode of venous thromboembolism. Antepartum heparin was withheld, but anticoagulant therapy was given for four to six weeks post partum. Our primary objective was to determine the rate of antepartum recurrence of venous thromboembolism. Laboratory studies were performed to identify thrombophilia in 95 women. RESULTS: Three of the 125 women (2.4 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 0.2 to 6.9 percent). There were no recurrences in the 44 women who had no evidence of thrombophilia and who also had a previous episode of thrombosis that was associated with a temporary risk factor. Among the 51 women with abnormal laboratory results or a previous episode of idiopathic thrombosis, or both, 3 (5.9 percent) had an antepartum recurrence of venous thromboembolism (95 percent confidence interval, 1.2 to 16.2 percent). CONCLUSIONS: The risk of recurrent antepartum venous thromboembolism in women with a history of venous thromboembolism is low, and therefore routine antepartum prophylaxis with heparin is not warranted.

Adult↗
PubMed2000

An exploration of inter-relationships between contact angle, inverse phase gas chromatography and triboelectric charging data.

Surfaces of pharmaceutical powders have been assessed using contact angle, inverse phase gas chromatography (IGC) and triboelectric (electrostatic) charging techniques. The suitability of the Dynamic Angle Tester (DAT), an instrument based on the sessile drop technique, in determining contact angles and then the surface energy of pharmaceutical powders was assessed. The dispersive components of the surface energy of powders determined from the DAT and IGC method ranked the powders in the same order. The dispersive component values obtained by IGC were, as expected, higher than those from the DAT, due to IGC probing the highest energy sites on the powder surface. IGC and triboelectric studies allow materials to be characterised in terms of their electron donating-accepting tendencies, so inter-relationships between the data from the two techniques were explored. Although the data set was limited, there appeared to be a correlation between the charges developed by the powders on contact with stainless steel and the ratio of the electron-donating to electron-accepting tendencies of the materials as obtained from IGC.

Chemistry, Pharmaceutical↗
PubMed2000

Abdominal content containment: practicalities and outcome.

BACKGROUND: Alternatives to fascial closure of the abdominal wall are increasingly used in critically ill patients. They pose practical and logistical problems in management which are described in this single-institution study. METHODS: Between January 1994 and December 1997, 157 predominantly young male patients (100 trauma and 57 non-trauma) underwent temporary abdominal content containment (t-ACC) using plastic bags or polyglactin mesh. Indications for t-ACC were severe sepsis requiring reoperation, abdominal compartment syndrome, abdominal wall tissue loss or a combination of these. A total of 385 laparotomies were performed. RESULTS: Two t-ACC procedures failed owing to technical error and two were complicated by enteric fistulas. Six patients underwent early definitive abdominal closure within 15 days. The remaining survivors had a protracted hospital stay (mean(s.d.) 44.6(26.6) days) and all developed incisional hernias which were challenging to repair. The overall mortality rate was 44 per cent. CONCLUSION: Plastic bags were cheaper and as effective as polyglactin mesh for t-ACC. Survivors require a multidisciplinary approach in management, undergo a protracted hospital stay and later need complex incisional hernia repairs.

Abdominal Injuries↗
PubMed2000

CxGELSIX: a novel preparation of type VI collagen with possible use as a biomaterial.

PURPOSE: This study was initiated to evaluate tissue acceptance and stability of a novel type VI collagen preparation (CxGelsix) as a biomaterial in the rabbit corneal stroma. We hypothesized that CxGelsix, embedded intrastromally, does not have any adverse affect on surrounding corneal tissues, and remains intact in the presence of an acute inflammatory reaction during corneal wound healing. METHODS: Type VI collagen was extracted and purified from rabbit corneal stroma under nondenaturing conditions. This preparation, Gelsix, was concentrated and cross-linked with polyethylene glycol to produce a transparent film (CxGelsix). Discs of CxGelsix, 4.0-mm diameter, 9- to 35-microm thick were implanted intrastromally and clinically examined periodically for 4 months. In another experiment, implantation of CxGelsix, 2.0-mm-diameter, was followed by corneal wounding adjacent to the implant and examined clinically for 30 weeks. At the end of these periods, the tissues from these experiments were processed for light and transmission electron microscopy. RESULTS: An intralamellar 4.0-mm-diameter disc of CxGelsix does not alter the structure of corneal epithelium above the implant, suggesting normal transport of nutrients through CxGelsix. Moreover, no structural abnormalities were seen in the rest of the cornea, and the cornea remains transparent. Although the cornea accepts the presence of CxGelsix disc as judged by clinical criteria, gradual degradation of the implant is seen ultrastructurally. CxGelsix is remarkably stable despite its exposure to endogenous enzymes during inflammation and wound healing. Partial degradation of the implant occurs only after many months, and it is gradually replaced with bundles of fine collagen fibrils reminiscent of normal cornea. CONCLUSION: The results of this study suggest that CxGelsix is potentially useful as a biomaterial.

Animals↗
PubMed2000

[Prevention and treatment of obesity since childhood: strategy to decrease the non transmissible chronic diseases in adult].

The prevalence of obesity among children and teenagers is increasing by 1.5% per year, probably due to a higher consumption of highly caloric foods and to physical inactivity. Hypercholesterolemia, increased insulin levels and high blood pressure of childhood obesity, precede atherosclerosis, coronary artery disease, diabetes and hypertension in adulthood. The prevention of childhood obesity is an efficient strategy to decrease the prevalence of non transmissible chronic diseases in the adult. The recommendations of experts committees for the prevention, diagnosis and treatment of childhood obesity are reviewed. They aim at a change in dietary habits and increasing physical activity. A well balanced healthy diet and a decrease in physical inactivity time will result in a successful treatment approach for obesity.

Adult↗
PubMed1999

Potential roles of metalloprotease mediated ectodomain cleavage in signaling by the endothelial receptor tyrosine kinase Tie-1.

The orphan receptor tyrosine kinase Tie-1 is expressed predominantly in endothelial cells. Expression of this receptor is increased in physiologic angiogenesis and pathologic situations including tumor growth and arteriovenous malformations. Tie-1 is essential for vascular development where it acts in later stages of angiogenesis to suppress endothelial activation and stabilize the newly formed vessel. Stimulation of protein kinase C in endothelial cells results in endoproteolytic cleavage of Tie-1, releasing the extracellular ligand-binding domain of the receptor. We show that this is mediated by a metalloprotease. Immunoprecipitation and immunoblotting of lysates prepared from human placentas confirm that Tie-1 truncation occurs in vivo. We propose cleavage of this receptor may be a mechanism for inducing vessel destabilization by preventing ligand-activated signaling through Tie-1. Using an antibody that recognizes the carboxy terminus of the intracellular domain, we show that the Tie-1 endodomain formed on cleavage persists as a cell-associated fragment for several hours. Subcellular fractionation reveals this tyrosine kinase containing receptor fragment to be localized in the membrane fraction of the cell. Immunoprecipitation with antibodies recognizing phosphotyrosine demonstrates that cleavage of Tie-1 stimulates association of newly generated endodomain with cellular phosphoproteins. Furthermore, there was a marked induction of tyrosine phosphorylation of several proteins after PMA-induced endodomain generation. These data indicate that ectodomain cleavage may be a mechanism for down-regulating ligand-induced signaling through Tie-1 while activating an alternative ligand-independent signaling pathway in endothelial cells. Ectodomain cleavage occurs in some other receptor tyrosine kinases. We suggest that rather than solely being a means of down-regulating receptor activity, ectodomain cleavage may be a novel way for a receptor to switch between two alternative signaling pathways.

Cells, Cultured↗
PubMed1998

Mivacurium compared with three different doses of suxamethonium for nasotracheal intubation.

Suxamethonium in the doses of 1.0, 0.5 and 0.25 mg/kg was compared with mivacurium 0.15 mg/kg in 80 patients requiring nasotracheal intubation for maxillofacial surgery in a double-blind randomized controlled trial. Anaesthesia was induced with thiopentone 5 mg/kg and alfentanil 15 micrograms/kg. Patients were randomly allocated to one of the four relaxant groups. Anaesthesia was maintained with enflurane in 70% nitrous oxide and 30% oxygen and analgesia provided with intravenous pethidine 0.5 to 1.5 mg/kg and rectal indomethacin 100mg. All patients given mivacurium or suxamethonium 1 mg/kg had acceptable intubating conditions. Significantly fewer patients given suxamethonium 0.5 mg or 0.25 mg/kg had acceptable intubating conditions (90% and 70% respectively) (P = 0.003). Poor intubating conditions requiring additional relaxation were seen in two patients given suxamethonium 0.25 mg/kg and two given 0.5 mg/kg, while no patients given suxamethonium 1.0 mg/kg or mivacurium 0.15 mg/kg required additional relaxation (P = 0.004). Only four patients had postoperative myalgia, all of whom were given suxamethonium 0.5 mg/kg or more but no significant difference between groups could be demonstrated.

Adult↗
PubMed1997

Beta-ig. Molecular cloning and in situ hybridization in corneal tissues.

PURPOSE: To identify a protein that copurifies with type VI collagen from rabbit cornea and to determine its cell source in rabbit corneal tissues by in situ hybridization. METHODS: Type VI collagen was extracted from cornea with urea and purified by ammonium sulfate precipitation and gel chromatography. The purity of the collagen was assessed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). On reduction with mercaptoethanol or dithiothreitol, the alpha chains of type VI collagen ran into the gel. In addition to the type VI collagen polypeptides, an extra 68-kDa protein band appeared, suggesting that this protein is present as a large molecular weight component before reduction. Amino acid sequencing indicated that protein was related to beta ig-h3 from humans. Western blot analysis was used to determine immunologic similarity to this human protein. A rabbit stromal cell cDNA library was screened with human beta ig-h3 cDNA probe. Positive clones were sequenced and analyzed for sequence homology. Oligonucleotide probes prepared from rabbit cDNA sequences were used for Northern blot analysis and in situ hybridization of corneal tissues. RESULTS: Electroblotting of the SDS-PAGE and amino acid sequence analysis of the first 10 N-terminal amino acids of the 68-kDa band gave 100% homology with a known protein produced by human adenocarcinoma cells, beta ig-h3. This 68-kDa protein was identical immunologically to beta ig-h3 by Western blot analysis. Sequence analysis of a rabbit cDNA clone contained the whole coding region and had high identity with both human beta ig-h3 and mouse beta ig-m3. The deduced amino acid sequence had 92% identity with these species. An oligonucleotide probe from the rabbit cDNA sequence detected a single band of mRNA from cultures of stromal cells consistent in size with human beta ig-h3 mRNA. The authors refer to the rabbit form of beta ig-h3 as beta ig because the protein was obtained from normal rabbit cornea and the mRNA comes from primary cultures of rabbit stromal cells and not from a cloned cell line. In situ hybridization of rabbit corneal tissue indicated that the beta ig mRNA is located primarily in the epithelium of normal adult cornea, in fetal stromal cells, and both endothelium- and stroma-derived cells in healing corneal wounds. Normal adult endothelium and stroma did not show beta ig mRNA label. CONCLUSIONS: The highly conserved amino acid sequence homology between the human, mouse, and rabbit proteins and the temporal expression of beta ig message during corneal healing and development suggest this protein plays an important role in the morphogenesis of corneal tissues.

Amino Acid Sequence↗