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Biomedical subjects

C Barnes

Publications and source records attributed to C Barnes.

At least 55 records · Page 3Linked to original sources
PubMed2003

The angiogenic receptor KDR is widely distributed in human tissues and tumours and relocates intracellularly on phosphorylation. An immunohistochemical study.

AIMS: Angiogenesis is an important factor in tumour growth and metastasis. Vascular endothelial growth factor receptor 2 (VEGFR-2) or KDR plays a crucial role in angiogenesis. The aim of this study was to raise and characterize antibodies against phosphorylated KDR which could be used for studies on human tissues to assess KDR activation and novel inhibitors of KDR activation in clinical trials. METHODS AND RESULTS: Three monoclonal antibodies and one rabbit polyclonal antiserum were produced. The specificity of the antibodies was confirmed by ELISA. One of the mouse antibodies and the rabbit polyclonal antiserum reacted with a 200-kDa band on a Western blot of human umbilical vein endothelial cell (HUVEC) lysates, the molecular weight of KDR. Immunohistochemical staining showed that phosphorylated KDR is present in a wide variety of normal tissues including liver, colon and placenta, and is not restricted to endothelium. It was also present in a number of human tumours including breast carcinomas, colonic carcinomas and non-Hodgkin's lymphomas. The pattern of staining was membranous, cytoplasmic and nuclear. CONCLUSIONS: This study has shown that phosphorylated KDR is present in a wide variety of tumour and tissue types and is not confined to endothelium.

Animals↗
PubMed2003

Velcroholism.

Explore the source record for details and available documents.

Anemia, Iron-Deficiency↗
PubMed2003

Survey of the growth characteristics and body composition of Fulani children in a rural hamlet in northern Nigeria.

This paper reports the results of a cross-sectional study of the growth of Fulani children, aged 1-16 years, living in the Jos Plateau of northern Nigeria. This particular population of Fulani are semi-nomadic pastoralists whose economy and culture are centered on cattle. We measured the heights and weights of 176 girls and 164 boys and determined their body composition parameters (fat content, fat-free mass, and phase angle) using bioelectrical impedance analysis. The body mass index values for the boys and girls were 14.9 and 15.0 kg/m2, respectively. When the heights and weights of the Fulani children were compared against World Health Organization standards, the incidence of stunting and underweight was high: 46 per cent of the girls and 57 per cent of the boys, respectively, had weight Z-scores below -1.0, and 42 per cent and 57 per cent had height Z-scores below -1.0. Even when weight was adjusted for height, the boys and girls fell well below their age- and gender-matched standards. The percentage fat content of the children declined with age such that by age 16 years the fat content of the boys was 10 per cent and that of the girls 20 per cent. Although the Fulani children were significantly shorter and lighter than the international standards, their phase angle value (determined by bioelectrical impedance analysis), which is a measure of body cell mass and the overall vitality and health of tissue membranes, was comparable to those of similarly aged healthy children in the United States. These results indicate that although a large proportion of the Fulani children who inhabit the Jos Plateau are stunted and underweight, the bioelectrical properties of their tissue membranes suggest that they are relatively healthy. It is not known if the slow growth of the Fulani children has a genetic basis or if it is the result of nutritional shortcomings.

Adolescent↗
PubMed2002

Sedation practices for Australian and New Zealand paediatric oncology patients.

OBJECTIVES: Paediatric oncology patients often require repeated bone marrow aspirates and lumbar punctures. These procedures commonly require sedation and analgesia. The Australian and New Zealand College of Anaesthetists and the American Academy of Pediatrics have published guidelines that provide recommendations on monitoring and staffing requirements during sedation of paediatric patients. A survey was conducted of the oncology units in Australia and New Zealand in order to compare current practices with published guidelines. METHODS: Telephone interviews were conducted with nursing or medical staff members. RESULTS: Fourteen oncology units collectively perform approximately 130 procedures each week, of which 74% are performed under general anaesthesia. Of the remainder, most are performed using conscious sedation. Most units adhere to published recommendations regarding equipment and staffing during procedures performed under sedation. Only a minority of units follow guidelines regarding documentation; fasting requirements; observation and documentation of vital signs during and after the procedure; and obtaining informed consent for procedures performed using sedation. CONCLUSION: Sedation practices among paediatric oncology units in Australia and New Zealand vary. None of the units fully adhere to published guidelines on childhood sedation. Paediatric oncology units should be familiar with the content of these guidelines and make an informed decision as to their usefulness, both in directing best clinical practice, and in supporting current practice in the event of medico-legal challenge.

Analgesics↗
PubMed2002

A method for measuring particle number emissions from vehicles driving on the road.

Earlier research has demonstrated that the conditions of dilution of engine exhaust gases profoundly influence the size distribution and total number of particles emitted. Since real world dilution conditions are variable and therefore difficult to simulate, this research has sought to develop and validate a method for measuring particle number emissions from vehicles driving past on a road. This has been achieved successfully using carbon dioxide as a tracer of exhaust gas dilution. By subsequent adjustment of data to a constant dilution factor, it is possible to compare emissions from different vehicles using different technologies and fuels based upon real world emission data. Whilst further optimisation of the technique, especially in terms of matching the instrument response times is desirable, the measurements offer useful insights into emissions from gasoline and diesel vehicles, and the substantial proportion of particles emitted in the 3-7 nanometre size range.

Air Pollutants↗
PubMed2002

Post-thrombotic syndrome.

Post-thrombotic syndrome (PTS) is a potentially disabling complication occurring in up to 67% of adult patients following deep venous thrombosis (DVT). PTS has recently been recognised in children. We present three cases of symptomatic PTS in children, which occurred following the use of central venous lines (CVLs). In two cases, no symptoms of acute thrombosis were noted. The cases highlight the clinical presentation of this syndrome. A review of the literature revealed two reports describing PTS occurring in children following DVT with an estimated incidence of 7-12%. It is concluded that PTS is an important complication of DVT in children. The clinical findings of pain, swelling, and brawny induration are similar to adult patients. The effect on growing limbs is not known. Paediatricians should be aware of the potential of PTS in all children who are at risk of DVT, including patients with malignancy, congenital heart disease, and children who have had previous CVLs, even in the absence of documented acute DVT.

Adolescent↗
PubMed2001

Laryngo-pharyngeal carcinoma in childhood.

Laryngo-pharyngeal carcinoma is rare in children. We present two cases of squamous cell carcinoma of the laryngopharynx in children less than 15 years of age. Both patients presented with a prolonged history of symptoms and extensive disease at diagnosis. Early visualisation the vocal cords with flexible larygnoscopy is important in children presenting with symptoms suggestive of laryngeal pathology. Long-term complications of definitive local therapy for laryngopharyngeal carcinoma are important in young children. Evidence from studies in adult patients suggests that adjuvant chemotherapy may play a role in laryngeal preservation in a select group of patients.

Carcinoma, Squamous Cell↗
PubMed2001

Aspergillus laryngotracheobronchial infection in a 6-year-old girl following bone marrow transplantation.

Localised fungal infection of the larynx and tracheobronchial tree is extremely uncommon. We report the case of a 6-year-old girl with acute lymphocytic leukaemia, who developed symptoms of upper airways obstruction 6 months after a cord blood transplant. Bronchoscopy showed a pale plaque lesion in the larynx and tracheobronchial tree. Aspergillus fumigatus was cultured from a biopsy of the lesion. The patient was treated successfully with a prolonged course of amphotericin B and assessed with multiple surveillance bronchoscopies.

Amphotericin B↗
PubMed2001

Hourly variation of airborne ragweed pollen in Kansas City.

INTRODUCTION: Ragweed pollen is one of the major causes of allergic rhinitis in the midwest United States. Previous studies have demonstrated that ragweed pollen production begins after sunrise and airborne pollen levels peak several hours later. Variations in this pattern that may be of clinical importance within a small region and the effect of weather on these variations have not been investigated. METHODS: Volumetric pollen collectors were stationed at four sites around the metropolitan area. Ten-minute grab samples were taken at each location every 2 hours for continuous 24-hour periods during the 1997 ragweed season. The downtown location had a weather station that logged meteorological conditions at hourly intervals during this time. Ragweed pollen grains were counted microscopically at 400 x. Uninterrupted data covering at least 20 days during the season were evaluated for each collection site. RESULTS: The lowest ragweed pollen counts occur at 6:00 AM and the highest occur at noon for both suburban and urban sites. Rainfall was seen to be the most influential weather-related factor. Significant rainfall events effectively removed pollen grains from the air. CONCLUSIONS: Though ragweed pollen emission begins at 6:00 AM, peak pollen exposure occurs at midday. This observation is in agreement with many other studies. The myth that highest ragweed exposure occurs in the early morning hours is not supported by this or previous studies.

Air Pollution↗
PubMed2001

Allergenic materials in the house dust of allergy clinic patients.

INTRODUCTION: Environmental agents including animal, fungal, tree, and weed antigens are known to cause allergic rhinitis and asthma. The following study was performed to measure the antigen concentration of several of these in house dust of children seen in an allergy clinic. Comparisons are made between household allergen levels of children seen for asthma and children seen for other reasons. METHODS: Dust samples were solicited from patients in a pediatric allergy specialty clinic and other individuals associated with the clinic. Persons submitting dust were asked to complete a questionnaire describing their house. Samples were extracted, centrifuged, and filtered for sterility. Samples were stored in 50% glycerol at -20 degrees C. Specific antigens for Alternaria, Cladosporium, Aspergillus, Candida, Dermatophagoides farinae, cat, dog, oak, fescue, ragweed, plantain, and cockroach were measured using inhibition assays developed with whole antigen extract. Allergens Der p1, Der f 1, Alt a 1, and Alt a 70 kD were measured using double monoclonal antibody assays. RESULTS: Significant concentrations of whole antigen from cat, dog, oak, Alternaria, and Cladosporium were detected. Between 0.1 and 18 microg of Der f1 and Der p1 per gram of dust were also measured. Alt a 1 and Alt a 70 kD levels varied between 3.0 and 1000 U/g of dust. Significant positive correlations were observed in levels of dust mite and Alternaria allergen for patients with an evaluation of asthma. CONCLUSIONS: We found measurable levels of fungal antigens (Alternaria, Cladosporium), mite antigens, and animal antigens (dog and cat) in the majority of dust samples in this self-selected set of allergy clinic patients. Specific allergens Alt a 1, Alt a 70kD, and Der p 1 were significantly higher in the homes of asthmatic patients when compared with patients seen for reasons other than asthma. These studies support the hypothesis that fungal allergen exposure is an important component in the pathogenesis of the clinical condition known as asthma.

Air Pollution, Indoor↗
PubMed2001

Helicobacter pylori and tonsillectomy.

Tonsillar tissue is a component of mucosa-associated lymphoid tissue (MALT), which has evolved to protect vulnerable mucosal surfaces. Helicobacter pylori, implicated as an aetiological factor in duodenal ulcers and gastritis, induces the appearance of lymphoid aggregates (MALT) in the stomach. This organism is cytotoxic via a nitric oxide synthase cascade. The possibility that tonsillar tissue processes Helicobacter pylori or that Helicobacter pylori can colonize the palatine tonsils is explored. The study design was that of a prospective study. We determined if Helicobacter pylori (i) forms part of the normal microenvironment of the tonsil, (ii) plays a role in the pathogenesis of tonsillitis and (iii) is associated with increased expression of inducible nitric oxide synthase (iNOS) in macrophages of the tonsil. Serology for Helicobacter pylori was performed on 50 patients undergoing tonsillectomy. Tonsillar specimens were monitored for urease activity by CLO test (a sealed plastic slide holding an agar gel, which contains urea and detects the urease enzyme of Helicobacter pylori), and immunocytochemically probed for Helicobacter pylori and iNOS expression. The mean age of this patient group was 17.2 years (3-36 years). Fourteen (28%) were sero-positive for Helicobacter pylori but no evidence of this pathogen was found in any tonsillar specimen. The number of macrophages staining for iNOS, per field, under a magnification of x40, was increased in sero-positive patients (13.3 +/- 1.3 versus 9.9 +/- 0.7; P = 0.01). Helicobacter pylori does not appear to colonize the tonsil. We believe that Helicobacter pylori primes the tonsils by inducing macrophage iNOS expression. The higher expression in sero-positive patients is a reflection of a pro-inflammatory reaction to Helicobacter pylori that is both local and systemic.

Adolescent↗
PubMed2001

Spore germination increases allergen release from Alternaria.

Allergen released from individual spores of the fungus Alternaria has not been investigated. Germination of spores has been suggested to increase allergen release. This study examined allergen released from individual spores and the effect of germination on allergen availability. Allergen release was determined with the Halogen (Inhalix, Sydney, Australia) immunoassay, by use of serum IgE from Alternaria -sensitized subjects and 3 Alt a 1-specific antibodies. Not all spores released allergen. Germination of the spores significantly increased the proportion that released allergen (P < .0001 for all antibodies). Alt a 1 may be a minor contributor to the total allergen released from spores except when spores have germinated. How these results reflect the allergen content of spores in the air that we breathe requires investigation.

Alternaria↗
PubMed2000

Microbial iron transport via a siderophore shuttle: a membrane ion transport paradigm.

A mechanism of ion transport across membranes is reported. Microbial transport of Fe(3+) generally delivers iron, a growth-limiting nutrient, to cells via highly specific siderophore-mediated transport systems. In contrast, iron transport in the fresh water bacterium Aeromonas hydrophila is found to occur by means of an indiscriminant siderophore transport system composed of a single multifunctional receptor. It is shown that (i) the siderophore and Fe(3+) enter the bacterium together, (ii) a ligand exchange step occurs in the course of the transport, and (iii) a redox process is not involved in iron exchange. To the best of our knowledge, there have been no other reports of a ligand exchange mechanism in bacterial iron transport. The ligand exchange step occurs at the cell surface and involves the exchange of iron from a ferric siderophore to an iron-free siderophore already bound to the receptor. This ligand exchange mechanism is also found in Escherichia coli and seems likely to be widely distributed among microorganisms.

Aeromonas hydrophila↗
PubMed2000

Comparison of the Burkard and Allergenco MK-3 volumetric collectors.

BACKGROUND: The Burkard sampler is a widely used volumetric pollen and spore collector, in part, because it is wind-oriented, it has consistent flow characteristics, and it permits time-discrimination of collected particles. Its main disadvantages are that it is heavy, expensive, and visual counting is very time-consuming. A less-expensive volumetric collector with time discrimination capabilities could permit more widespread particle counting which would enhance our understanding of aerobiology. OBJECTIVE: The objective of this study is to compare the collection recoveries of the Burkard sampler with a less-expensive non-wind oriented collector, the Allergenco MK-3, under various wind speeds. METHODS: Pollen and spore counts were compared on 20 sampling days during the spring pollen season using a Burkard and Allergenco MK-3 located next to each other on the roof of a 5-story hospital building. A weather station was placed nearby and wind velocity was concurrently measured. RESULTS: The median wind velocity was 6 miles/hour with a maximum of 35 miles/hour. The Burkard and Allergenco MK-3 collectors displayed similar collection characteristics at all wind velocities for both pollen and spores. The Burkard gave lower counts than the Allergenco when absolute particle counts were low and similar values at higher absolute counts. CONCLUSIONS: Given our data, we conclude that ambient wind speed has no significant effect on collection efficiency at velocities commonly found on the roof of our hospital and that the collection characteristics of the Burkard and Allergenco MK-3 are comparable.

Air Pollutants↗
PubMed2000

Comparison of outdoor allergenic particles and allergen levels.

INTRODUCTION: Spore and pollen counts have been used traditionally to determine aeroallergen exposure. Using a liquid based collector and enzyme immunoassays, we have developed methods for measuring airborne allergen concentrations. In this work we test the hypothesis that airborne allergen concentrations are directly related to spore and pollen counts. METHODS: Test samplers used included a high-volume cyclonic liquid impinger (SpinCon) and a standard spore trap (Burkard). Samples were collected on a weekly basis from May to October and were analyzed microscopically for spores and pollen grains. The liquid samples were analyzed by enzyme-linked immunoassay for the presence of allergens from Alternaria, Cladosporium, Aspergillus, oak, fescue, ragweed, and plantain. Specific Alternaria allergens Alt al and GP70 also were measured. RESULTS: Pollen counts for the SpinCon and Burkard collectors were similar, though spore counts were lower with the SpinCon. Detectable amounts of three of the seven allergenic species including fescue, ragweed, and Alternaria were present in air samples. Concentrations of pollens were seen in their respective seasons while fungal allergen levels varied throughout the period. Allergen levels generally agreed with particle counts, however peak allergen levels and peak particle counts for individual species did not correlate well. CONCLUSIONS: At flow rates of 236 L/min, the SpinCon is comparable to the Burkard for counting airborne pollen and spores. Samples collected by the SpinCon permit quantitative determination of allergen levels in outdoor air. The poor correlation between measured airborne allergen and related particles indicates the potential for significant allergen exposure in the absence of identifiable particles in air.

Air Pollutants↗