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Biomedical subjects

V G Daniels

Publications and source records attributed to V G Daniels.

16 recordsLinked to original sources
PubMed1984

General practitioner surveillance of azatadine maleate/pseudoephedrine sulphate ('Congesteze') for the treatment of upper respiratory tract congestion.

A post-marketing, general practitioner surveillance programme involving 12,679 patients with upper respiratory congestion was carried out to assess how well tolerated was symptomatic treatment with a combination oral preparation containing azatadine maleate (1 mg) and pseudoephedrine sulphate (120 mg) given twice daily for up to 15 days. The improvement which patients experienced in the symptoms of sneezing, running nose, stuffy nose, watery eyes and itchy eyes was also evaluated. Analysis of the results showed that 97% of the patients experienced some relief. The incidence of drug-related side-effects was 4% but only 253 (2%) patients discontinued treatment for this reason. The side-effect most frequently reported was drowsiness and this was considered to be probably or possibly due to treatment in 332 (3%) of the patients.

Adolescent↗
PubMed1979

Postnatal amino acid uptake by the rat small intestine. Changes in membrane transport systems for amino acids associated with maturation of jejunal morphology.

The uptake of a number of amino acids by the developing small intestine of the rat was investigated in vitro. L-valine, L-leucine, L-methionine, L-phenylalanine, L-arginine and L-lysine were all taken up by active transport and concentrated within the jejunal mucosa. GABA was not actively transported by the jejunum. The kinetics of carrier transport of amino acids was determined from birth to maturity. The Michaelis constant (Km) of the L-leucine, L-methionine, L-arginine and l-lysine transport systems was found to be low postnatally and increased with age, particularly after the time of weaning. The rate of l-leucine, L-methionine, L-phenylalanine and L-lysine transport (Vmax) was high postnatally but decreased after weaning. Neutral amino acids were transported at higher rates than basic amino acids. l-arginine was poorly transported by the jejunum. The specificity of transport systems for amino acids was investigated in inhibition studies. Amino acid transport systems appeared to be polyfunctional in the postnatal period but were more specific in post-weaned animals. The changes in kinetics and specificity of amino acid transport in the small intestine are discussed with reference to their possible functional significance and to the maturational changes in the jejunum, particularly with the appearance of a functionally distinct absorptive cell lining the intestinal villi during the third postnatal week (the time of weaning).

Aging↗
PubMed1979

Postnatal amino acid uptake by the rat small intestine. Energetics of membrane transport systems for amino acids in the developing jejunum.

The energetics of amino acid uptake by the developing small intestine was investigated in vitro. L-valine, L-leucine, L-phenylalanine, L-methionine, L-lysine and L-arginine were all actively transported by the newborn rat jejunum. Metabolic inhibitors (e.g. 2,4-dinitrophenol) significantly reduced uptake of all amino acids but uptake against a concentration gradient was not totally abolished. Uptake of all amino acids was reduced at low[Na+]. Inhibition of transport of neutral amino acids by reduced luminal [Na+] was greater than that of basic amino acids, and the tissue was barely able to concentrate the neutral amino acids. [Na+] affected the Michaelis constant (Km) of neutral transport systems for their substrates; for the basic amino acids Km values were unaffected by the presence or absence of Na+. Ouabain significantly inhibited neutral amino acid uptake but had no effect on L-lysine or L-arginine uptake. These results are discussed in terms of the Na+ gradient hypothesis for amino acid transport, and the site of energy input to active transport. The role of glycolysis in providing energy for intestinal transport in the neonatal rat and the efficiency of Na+ dependent and independent transport mechanisms are considered. It is concluded that the energetics of amino acid transport systems in neonatal and adult rats are essentially similar.

Amino Acids↗
PubMed1973

The influence of exogenous steroids on macromolecule uptake by the small intestine of the new-born rat.

1. Plasma concentrations of cortisol and corticosterone measured by competitive protein binding in rats between 5 and 28 days after birth have been related to the intestinal uptake of [(125)I]polyvinyl pyrrolidone (PVP).2. Plasma cortisol concentration was consistently low throughout the period studied, but there was an increase in plasma corticosterone concentration at the time (18-21 days) when PVP uptake declined to zero (closure).3. Injection of a large dose of cortisone acetate 5 days after birth resulted in precocious closure; PVP uptake declined progressively to zero during the 6 days following the injection. Injection of this steroid at 12 days of age caused closure within 4 days.4. Precocious closure induced by cortisone acetate was closely comparable histologically with natural closure; the decline in PVP uptake was associated with the progressive displacement of vacuolated cells from the villi of the terminal intestine.5. Injection of corticosterone at either 5 or 12 days after birth also reduced PVP uptake. However, the reduction was transient and uptake returned to control levels some days after the injection.6. The temporary reduction in PVP uptake following corticosterone injection was not associated with any change in the histological appearance of the small intestine at the light microscope level.7. The injection of either cortisone acetate or corticosterone was followed by a period of impaired body growth and also a reduction of adrenal weight in animals injected at 12 days but not in animals injected at 5 days.

Adrenal Glands↗
PubMed1973

The effect of adrenalectomy or pharmacological inhibition of adrenocortical function on macromolecule uptake by the new-born rat intestine.

1. Bilateral adrenalectomy in 18-day-old rats resulted in an extension by approximately 4 days of the period during which the villous epithelial cells of the small intestine took up polyvinyl pyrrolidone (PVP) of mean mol. wt. 160,000.2. The eventual termination of PVP uptake (;closure') closely resembled normal closure in control animals: the time course of the decline in uptake and the histological changes indicated that more mature ;PVP-impermeable' cells progressively ascended the villi.3. Injection of Metopirone was ineffective in animals 10 days after birth, but when injected after day 13 caused closure within 3 days.4. Metopirone injection significantly reduced the plasma concentration of corticosterone and caused a marked rise in the plasma concentration of deoxycorticosterone.5. Aminoglutethimide injection also produced precocious closure and had an effect similar to Metopirone on the plasma concentrations of corticosterone and deoxycorticosterone.6. Injection of Metopirone or aminoglutethimide increased the relative adrenal weight compared with control animals. Aminoglutethimide was more effective and caused approximately a 100% increase in adrenal weight.

Adrenal Glands↗