Biomedical subjects
Publications and source records attributed to A Davies.
Concentrations of nitrate and nitrite have been determined in a range of foods and the dietary intake estimated from the MAFF Total Diet Study. The estimated dietary intake of nitrate ion for the UK population was 54 mg/day and the estimated dietary intake of nitrite ion was in the range 2.4-4.2 mg/day in 1985. The main source of nitrate in the diet is from the consumption of vegetables.
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Thirty-one patients with acute cerebral infarction were treated with the thrombolytic agent urokinase for either a single or a double infusion period, each of ten hours. The effects of urokinase therapy administered at dosage rates of 1,200, 1,500 or 1,700 CTA urokinase units per pound of body weight per hour were followed by serial blood coagulation and other biochemical studies. In the dosage used, urokinase produced a prompt sustained increase, 20-fold to 40-fold, of plasma thrombolytic activity with relatively minor disturbance of the blood coagulation system. Nevertheless, hemorrhagic complications occurred in several patients and distinctly favorable therapeutic effects were not observed.
Plasma fibrinogen chromatography is a method for quantification of high molecular weight fibrinogen complexes (HMWFC), native fibrinogen and other fibrinogen derivatives in plasma. Enchanced formation of fibrin, intravascular coagulation, thrombus formation, etc., are reflected by elevation of plasma HMWFC, and the method distinguishes between subjects with normal and pathological rates of fibrin formation. Serial standard blood coagulation assays, including plasma fibrinogen chromatography, and neurological studies were performed on 220 patients admitted to a stroke unit. Findings from patients with cerebral infarction were compared against those of three control groups: (1)normals, (2)a stroke control group and(3)a stroke risk factor group. Plasma HMWFC findings were significantly (p less than 0.001) higher in the stroke risk factor group than in the normals. Plasma HMWFC values were significantly higher (p less than 0.001) in the cerebral infarction patients than in any of the control groups, and plasma fibrinogen, plasminogen, alpha1-antitrypsin and alpha2-macroglobulin also were significiantly higher (p less than 0.001) in the patients. The greater the degree of initial neurological deficit, the greater were plasma HMWFC values (p less than 0.001), and high HMWFC values were associated with poor clinical outcome. Plasma HMWFC values were significantly higher (p less than 0.001) in patients with intracerebral hemorrhage, subarachnoid hemorrhage and cerebral embolism. These findings docunment the fact that a high proportion of stroke patients have coagulopathy, characterized by pathological enhancement of fibrin formation.
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The results of a collaborative study are reported for the determination of 3-chloro-1,2-propanediol (3-monochloropropane-1,2-diol; 3-MCPD) in a wide range of foods and food ingredients, using gas chromatography with mass spectrometric detection and incorporating the use of a deuterated internal standard. After a pretrial study, 12 laboratories (6 United Kingdom, 1 Switzerland, 1 Japan, 2 United States, 1 The Netherlands, and 1 from the European Commission) were asked to analyze 12 test materials (as known duplicates or split-level samples) by using a prescribed procedure. The test materials consisted of duplicate samples of acid-hydrolyzed vegetable protein (containing 3-MCPD at 0.029 mg/kg), malt extract (0.055 mg/kg), wholemeal bread crumbs (0.030 mg/kg), salami (0.016 mg/kg), cheese alternative (0.043 mg/kg), and soup powder (split levels at 0.045 and 0.041 mg/kg). Repeatability ranged from 0.005 to 0.013 mg/kg and reproducibility, from 0.010 to 0.027 mg/kg, for the samples tested. Precision values were well within statistically predicted levels (HORRAT values of <1 for 5 of the 6 matrixes tested) and within method criteria prepared by a joint working group composed of the United Kingdom Ministry of Agriculture, Fisheries and Food and industry representatives. The study demonstrated the satisfactory validation of the method for quantifying 3-MCPD at levels of > or = 0.010 mg/kg. The limit of detection derived from separate in-house studies was estimated to be 0.005 mg/kg. The method was adopted First Action by AOAC INTERNATIONAL.
Thousands of ostomies are performed on children every year to treat a variety of acquired conditions and congenital anomalies. The parents of children with ostomies are faced with the challenge of successfully living with and managing their child's ostomy. These families need practical information and support, both from the professional community and from parents who have shared the responsibility of a child with an ostomy. A parental support network has been developed throughout the country to address some of the needs of these families. This article provides current information about the status of these networks: what they have to offer and how they can be accessed. These groups, which continue to evolve, demonstrate a trend within this unique population. The parents of a child with an ostomy no longer need to feel alone in their experience.
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In nine greyhound dogs, anaesthetized with chloralose-urethane, total lung resistance, volume of an isolated cervical tracheal segment and resistance of the isolated larynx were simultaneously measured. Three stimuli were tested: inhalation of a CO2-enriched gas mixture; histamine injected intravenously or administered by aerosol to stimulate primarily lung irritant receptors; and intravenous injection of capsaicin to stimulate primarily lung C-fibre receptors. The stimuli were applied in three successive conditions: neurally-intact animals; denervation of the right lung plus cold block of myelinated fibres in the left cervical vagus nerve; and further blockade of non-myelinated fibres in this nerve. Histamine and capsaicin increased lung and laryngeal resistances, and reduced tracheal volume, and the responses after denervation are consistent with the drugs acting by lung vagal reflexes. In neurally-intact animals, hypercapnia increased total lung resistance, decreased tracheal volume and lowered laryngeal resistance. After elimination of conduction in all myelinated fibres, CO2-induced changes in lung resistance and in tracheal volume were still present. However, the dilating effect of hypercapnia on the larynx diminished markedly. Elimination of all vagal pulmonary afferents abolished the residual laryngeal response to hypercapnia, lowered and delayed changes in tracheal volume and greatly reduced the increase in lung resistance. The results indicate that the laryngeal response to hypercapnia depends on vagal integrity, but the tracheobronchial constrictor effect of CO2 is less affected by vagal denervation.
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Sulphur dioxide inhalation (200 ppm) suppresses the inflation apnea in rabbits, but not in dogs. In rabbits, SO2 blocks airway slowly adapting stretch receptors (SAR) while rapidly adapting irritant receptors (RAR) remain largely unaffected. We studied cough elicited by mechanical irritation of the extrapulmonary airways and larynx in 13 rabbits and 4 dogs, anesthetized and spontaneously breathing, before and after SO2 inhalation. In rabbits, once SO2 had blocked the Hering-Breuer inflation reflex, mechanical stimulation of the trachea and carina failed to elicit cough; laryngeal stimulation was still effective though the response was attenuated. In dogs, SO2 inhalation (even up to 1,000 ppm) did not abolish either inflation apnea or cough to tracheobronchial mechanical stimulation. We recorded the response to mechanical probing of tracheal RAR, before and after SO2 exposure, in 6 rabbits. We found that the activity of these RAR was still present after cough and inflation apnea had disappeared. These results suggest a significant role of slowly adapting airway receptors in the cough reflex.
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