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Biomedical subjects

D S Brown

Publications and source records attributed to D S Brown.

At least 127 records · Page 7Linked to original sources
PubMed1985

The efficiency of utilization of metabolizable energy and apparent absorption of amino acids in sheep given spring- and autumn-harvested dried grass.

Three experiments were conducted with sheep given spring-harvested dried grass (SHG) and autumn-harvested dried grass (AHG). The first was a calorimetric trial to determine the metabolizable energy (ME) content of each grass and the efficiency with which sheep utilize their extra ME intakes above the maintenance level of intake. The second examined the relative amounts of extra non-ammonia-nitrogen (NAN) and individual amino acids absorbed from the small intestine per unit extra ME intake as the level of feeding was raised from energy equilibrium (M) to approximately 1.5 M. The third was a further calorimetric trial to investigate the effect of an abomasal infusion of 30 g casein/d on the efficiency of utilization of AHG. The ME content of the SHG (11.8 MJ/kg dry matter (DM] was higher than that of AHG (10.0 MJ/kg DM). The efficiency of utilization of ME for productive purposes (i.e. above the M level of intake; kf) was higher when given SHG (kf 0.54 between M and 2 M) than when given AHG (kf 0.43 between M and 2 M). As the level of intake of each grass was raised from M to 1.5 M there was a greater increment in the amounts of NAN (P less than 0.001) and the total amino acid (P less than 0.05) absorbed from the small intestines when sheep were given the SHG (NAN absorption, SHG 5.4 g/d, AHG 1.5 g/d, SED 0.54; total amino acid absorption SHG 31.5 g/d, AHG 14.3 g/d, SED 5.24). Infusion of 30 g casein/d per abomasum of sheep given AHG at M and 1.5 M levels of intake increased (P less than 0.05) the efficiency of utilization of the herbage from kf 0.45 to kf 0.57. Consideration is given to the possibility that the higher efficiency of utilization of ME in sheep given SHG may be related to the amounts of extra glucogenic amino acids absorbed from the small intestine which provide extra reducing equivalents (NADPH) and glycerol phosphate necessary for the conversion of acetate into fatty acids.

Absorption↗
PubMed1984

Observations on Schistosoma intercalatum in south-east Gabon.

Observations were made in the field and laboratory to determine the strain characteristics of Schistosoma intercalatum in south-east Gabon. For an isolate from Franceville, data are given for egg shape, behaviour of cercariae, seven enzyme systems separated by isoelectric focusing, and intermediate host specificity. Isolates from Cameroun (Edea) and Zaire (Kisangani) were included in a comparative study of the enzymes; Franceville and Edea isolates resembled each other but differed from the Zaire isolate in hexokinase and phosphoglucomutase. The Franceville isolate was polymorphic in phosphoglucomutase and glucosephosphate isomerase. The sum of characters indicates that S. intercalatum as known from south-east Gabon belongs to the strain found in Cameroun and western Gabon, rather than to the strain known from Zaire. More information is needed on strain distribution, particularly for an area including western Zaire and the Republic of the Congo, which appears to separate the two known strains.

Acid Phosphatase↗
PubMed1984

Gamma-aminobutyric acid stimulates the release of endogenous ascorbic acid from rat striatal tissue.

Gamma-aminobutyric acid (GABA) was found to induce the release of ascorbic acid from rat striatal homogenates and minces. This release was studied with the use of a rapid superfusion system with an on-line amperometric detector that monitors for the presence of easily oxidized substances (i.e., ascorbate, 3,4-dihydroxyphenylethylamine). The release was found to be calcium-independent and depolarization-dependent. This releasable pool of ascorbate could be replenished through nonstereospecific uptake. The releasing action of GABA was mimicked by the GABA agonist, muscimol, and was completely inhibited by the GABA antagonist, picrotoxin. The structural analogues of GABA, beta-alanine and gamma-hydroxybutyric acid, had no effect. These data indicate that ascorbate release is GABA-receptor mediated and synaptically localized.

Animals↗
PubMed1983

The nutritive value of rumen micro-organisms in ruminants. 3. The digestion of microbial amino and nucleic acids in, and losses of endogenous nitrogen from, the small intestine of sheep.

An experiment was conducted with three sheep maintained entirely by intragastric nutrition to estimate the digestibility of isolated individual constituents and amino acids (AA) of rumen micro-organisms (RMO) in the small intestine. Five levels of RMO were infused into the abomasum. The apparent and true disappearance of the individual components were measured by regression of abomasal input on the passage at the ileum. The true digestibility values of N, AA-N, DNA and RNA were 0.82, 0.85, 0.81 and 0.87, respectively. The digestibility of individual AA varied between 0.80 and 0.88, the only exceptions being diaminopimelic acid (0.37), histidine (0.68) and cystine (0.73), which were significantly lower than the average (0.847). The endogenous components in the ileal fluid in sheep given protein-free infusions, expressed in mg/kg live weight0.75 per d, were total N 42 and AA-N 20.

Amino Acids↗
PubMed1982

Impotence--the team approach to investigation and surgical treatment.

A multidisciplinary study group was established to assess impotent patients. One hundred and forty-eight patients were fully assessed and 25 potent volunteers underwent measurement of nocturnal penile tumescence (NPT). This report describes the selection process and results of surgical implantation of the American Medical Systems (AMS) inflatable and the Jonas silver-silicone prostheses.

Adult↗
PubMed1981

Distribution in Kenya of intermediate hosts of Schistosoma.

A major factor in the geographical distribution of endemic schistosomiasis in Kenya is the discontinuous distribution of intermediate hosts. Biomphalaria pfeifferi is the main transmitter of S. mansoni and is found in the altitude zone 300-2,300 m; its absence from the costal region results in the absence of endemic schistosomiasis mansoni amongst the large human population in the coastal region. Snails belonging to the Bulinus africanus group appear to be responsible for all transmission of S. haematobium; they occur from near sea-level to an altitude of about 1,800 but are discontinuously distributed. There appears to be considerable potential for increase in the areas in which each form of schistosomiasis is endemic, taking into account existing patterns of snail distribution and likely developments in irrigation and water conservation. New localities reported here considerably extend the known distribution in western Kenya of B. truncatus, which could serve as an effective intermediate host for S. haematobium if a suitable strain were to become established in Kenya.

Animals↗
PubMed1979

The Personality Research Form as a therapy outcome measure of social behavior.

Reported two studies that examined the efficacy of the Personality Research Form (PRF) as an outcome measure for interventions designed to increase social competence. In the first study (N = 83), the degree to which PRF scales can predict criteria frequently used in social skills training outcome research was examined, and the PRF was shown to be sensitive to such criteria. The second study (N = 24) assessed the relative degree to which the PRF scales and more frequently used outcome measures, including the above criteria, are affected by factors non-specific to social skills training interventions (suggestion for improvement). While three PRF scales were affected significantly, demand effects were much more pervasive on the other measures, which suggests that those measures can be used to obtain valid estimates of treatment effects only when experimental control of non-specific effects is possible. Two PRF scales, Affiliation and Exhibition, were shown to be both sensitive to criteria and resistant to demand effects, and as such may be useful as outcome measures in non-controlled clinical settings.

Behavior Therapy↗
PubMed1978

Layered membranes: a diffusion barrier to gases in teleostean swimbladders.

Flattened cells are dispersed in an overlapping fashion within the submucosa of closed (physoclistous) swimbladders. Within the cells are located round platelets best seen by phase or interference type microscopy. At the electron microscope level the platelets are revealed as repeated, numerous layers of membranous discs. Each disc is a bilayer with an enlarged rim. The bilayer is strongly and preferentially reactive to osmium tetroxide. Swimbladder walls are known to be highly resistant to passage of gases. The randomly disposed platelets with the highly ordered layering of membranes may provide that physical resistance to gas movement.

Air Sacs↗