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Biomedical subjects

R Davies

Publications and source records attributed to R Davies.

At least 307 records · Page 17Linked to original sources
PubMed1976

Beta adrenergic blockade and diuretic therapy in benign essential hypertension: A dynamic assessment.

Beta adrenergic receptor antagonists (beta blockers) differ greatly in their cardioselectivity and intrinsic sympathomimetic activity, and these differences may have important therapeutic consequences. We have therefore studied the effect on blood pressure, heart rate and plasma renin activity of the beta blocking drug oxprenolol (Trasicor) which has considerable intrinsic sympathomimetic activity, both alone and in combination with the benzothiadiazine cyclopenthiazide. Eleven patients with mild to moderate benign essential hypertension were randomly allocated to one of two treatment groups. Oxprenolol was given as the first drug to Group 1, and cyclopenthiazide as the first drug to Group 2. The patients were assessed before the start of treatment, after 2 to 3 weeks of treatment with one drug and after a further 2 to 3 weeks of treatment with both drugs. Heart rate, blood pressure and plasma renin activity were measured with the patients recumbent and after a standardized tilt to 85 degrees to provide a reflection of day to day cardiovascular stress. Oxprenolol reduced arterial blood pressure without inducing significant bradycardia. The addition of cyclopenthiazide had little further effect. Oxprenolol alone suppressed plasma renin activity both at rest and during tilt and also abolished the increase in plasma renin activity after administration of cyclopenthiazide. The combination of (1) moderate reduction of blood pressure. (2) inhibition of the otherwise inevitable increase in plasma renin activity with the use of a diuretic drug, and (3) only moderate inhibition of overall sympathetic activity indicates that it is possible to achieve physiologic balance with the appropriate beta blocking drug.

Adrenergic beta-Antagonists↗
PubMed1976

Analysis of butaclamol in serum by fluorescence induction.

A sensitive TLC-fluorometric method was developed for the analysis of butaclamol, a benzo[6,7]cyclohepta[1,2,3-de]-pyrido[2,1-a]isoquinoline derivative, in serum. The method involves cyclohexane extraction of serum samples followed by TLC of the concentrated extracts. The developed TLC plates were sprayed with an oxidizing reagent and heated at 110 degrees. Highly fluorescent spots were produced for butaclamol, which was well separated from metabolites and serum components. Fluorometric densitometry permitted quantitation with a sensitivity of 10 ng/spot application.

Adult↗
PubMed1976

Egg allergy, influenza vaccine, and immunoglobulin E antibody.

In a study of 70 patients with asthma, rhinitis, and eczema, those giving a definite history of allergic reactions to egg more frequently showed positive skin tests to egg extracts (p = less than 0.003), the wheal diameters of which were significantly larger (p = less than 0.01) than in patients with only a possible or no such history. Patients with a definite history of egg allergy had significantly higher levels of specific IgE antibody against egg yolk, egg white, and allantoic fluid than patients in the other two groups (p = less than 0.005). Seven patients, all of whom had given a definite history of allergy to egg, were found to have positive skin prick tests to influenza vaccine, at the concentration used in medical practice. Two of these patients had previously been given influenza vaccine and both had developed adverse reactions. Of the 22 patients giving a definite history of allergy to egg, the 7 (35 per cent) with positive skin tests to influenza vaccine had significantly larger skin tests and higher levels of specific IgE antibody to the egg extracts than the group as a whole (p = less than 0.001). Allergic reactions to influenza vaccine are likely to occur in patients who have a definite history of allergy to egg and large skin prick test reactions or high levels of specific IgE antibody to egg extracts. Those at risk can best be identified by skin prick testing with egg extracts and undiluted influenza vaccine.

Adolescent↗
PubMed1976

A role for antibody in the expression of cellular immunity to Salmonella typhimurium C5.

Immunisation of mice with alcohol-killed Salmonella typhimurium C5 vaccine before infection with Salmonella enteritidis 11RX enhanced the ability of these mice to control and eliminate a challenge dose of Salmonella typhimurium C5, compared to mice which only received live Salmonella enteritidis 11RX organisms. When alcohol-killed Salmonella enteritidis Se795 vaccine was used instead of the Salmonella typhimurium C5 vaccine, this effect was not observed. These observations imply that both humoral and cellular responses are important in the expression of immunity to slamonella infections. The bearing of these results on the observations of other workers is discussed.

Animals↗
PubMed1976

The role of thymus-derived cells in immunity to salmonella infection.

The ability of thymus-derived (T) cell depleted mice to eliminate a dose of the normally avirulent 11RX strain of Salmonella enteritidis was compared to that of normal mice by following the fate of the challenge organisms in the liver and spleen of both types of mice. Although the mice did not require normal numbers of T cells to survive infection with Salmonella enteritidis 11RX, T cell depletion reduced the ability of mice effectively to eliminate the organism from their tissues. In addition, T cell depletion abolished the ability of live Salmonella enteritidis 11RX vaccine to protect mice against a subsequent challenge with the virulent C5 strain of Salmonella typhimurium.

Animals↗
PubMed1976

The response of arginine vasopressin and plasma renin to postural change in normal man, with observations on syncope.

1. Fourteen mildly hydropenic normal volunteers were slowly tilted at a constant rate from the horizontal to the 85 degrees head-up position in order to study the interrelationship between plasma arginine vasopressin concentration, plasma renin activity and the change of plasma volume. 2. Nine subjects did not develop vaso-vagal symptoms and were studied for 45-60 min. Arginine vasopressin rose biphasically in all subjects: a small initial rise, which was seen at 3 min and persisted for 30 min, was followed by a striking rise between 30 and 45 min, when the fall of plasma volume had reached its maximum (17%). 3. Plasma renin activity reached a maximum at 30 min but fell by 45 min, as plasma concentration of arginine vasopressin rose. 4. Five subjects developed vaso-vagal symptoms 4-24 min after reaching 85 degrees when the study was terminated. A striking increase of arginine vasopressin concentration was seen within 4 min of syncope, but there was no change of plasma osmolality, cortisol concentration or renin activity.

Adult↗
PubMed1976

An international haematological survey.

Haematological surveys of adult population samples were conducted simultaneously in 12 countries, all but one of which are in Europe. Haematological estimations on samples from nine of the countries were made in one central laboratory. Differences between countries in the mean levels of haemoglobin (and haematocrit and red cell count) were found to be relatively small, and the prevalence of levels below the arbitrary WHO levels for anaemia were, on the whole, low. In males, the evidence suggests a fall in haemoglobin level throughout adult life, which increases slightly in advanced age. In females, there is no evidence of any important relationship between age and haemoglobin level.

Adolescent↗
PubMed1975

The effect of thiols on Saccharomyces fragilis.

Treatment of cell suspensions of Saccharomyces fragilis with 0.01 M beta-mercaptoethanol or dithiothreitol released a variety of substances of high and low molecular weight. Twenty-two high-molecular-weight glycoproteins were separated by a combination of chromatography on DEAE cellulose and polyacrylamide gel electrophoresis in presence of sodium dodecylsulphate. The carbohydrate components consisted of at least 95% mannose and the protein components had threonine and serine as the major amino acids. Only very small amounts of phosphorus were associated with the high-molecular-weight components. The low-molecular-weight substances werr probably released from the internal cell pool and uracil and hypoxanthine were identified as components of this fraction. It is suggested that in addition to breaking disulphide bridges in the cell wall the thiols may also render the plasmalemma permeable to certain low-molecular-weight substances. Such effects are not lethal since the yeast can be trained to grow in presence of 0.01 M mercaptoethanol.

Acid Phosphatase↗