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Biomedical subjects

A Skinner

Publications and source records attributed to A Skinner.

53 records · Page 3Linked to original sources
PubMed1984

An investigation of the effects of maltose and sucrose in the diet on the microbiology of dental plaque in man.

In a double-blind cross-over study, 24 dental students consumed 150 g of sucrose or maltose a day in various foods. After 15 days, plaque samples were collected from the distal surface of upper right first premolars; post-diet samples were collected four months later. The median total anaerobic count of plaque exposed to sucrose was significantly lower compared with maltose samples (p less than 0.05). Glucan-producing organisms per 100 anaerobes in the sucrose samples compared with the maltose (p less than 0.05). Streptococcus sanguis and Streptococcus mitior were the most frequently-isolated streptococci.

Adult↗
PubMed1982

The influence of the replacement of dietary sucrose by maltose on the formation and biochemistry of human dental plaque.

Samples of 2-day plaque were collected before and during two 25-day diet periods from 24 subjects taking part in a double-blind cross-over study involving sucrose- and maltose-rich diets. The mean change in plaque pH measured after exposure to the respective sugar during the 3rd week of both diet periods was similar. The dry weight of plaque did not vary significantly as either diet progressed but the lowest mean value obtained was in the 4th week of the maltose diet. The extracellular polysaccharide content of plaque was lower in the maltose group than in the sucrose group (p = 0.052). Plaque-invertase activity was not affected significantly by the diets but maltase activity was significantly higher in the 2nd and 4th weeks of the maltose diet (p = 0.039; p = 0.012). The results suggest that the polysaccharide matrix of plaque formed in the presence of maltose as opposed to sucrose is different, which could be explained by the known effect of maltose in vitro on plaque glucosyl transferases.

Adult↗
PubMed1979

General anaesthesia in sickle-cell disease.

General anaesthesia was administered on 284 occasions to 200 patients with sickle-cell disease at one hospital during July 1958 to June 1978. No intraoperative but six postoperative deaths occurred. The management of anaesthesia may have contributed to two of the postoperative deaths. Clinically uneventful anaesthesia did not appear to provoke severe sickling crises or to be responsible for mortality, but a contribution to postoperative morbidity could not be excluded. A simple, careful anaesthetic technique and selective but not routine blood transfusion appears to be associated with minimal anaesthetic morbidity and mortality in patients with sickle-cell disease.

Adolescent↗
PubMed1977

A comparison of three rapid methods for the detection of beta-lactamase activity in Haemophilus influenzae.

Three methods for rapidly detecting beta-lactamase activity in Haemophilus influenzae are compared. The chromogenic cephalosporin method was found to be the most easily performed and the reagents could be stored for up to three weeks. The phenol red method was simple to perform but the iodometric method was more time consuming. All three tests gave identical results.

Cephalosporins↗
PubMed1972

Excretion of deoxyribonucleic acid by lymphocytes stimulated with phytohemagglutinin or antigen.

When human lymphocytes are cultured in the presence of phytomitogens, 70-90% of the cells undergo blast transformation and synthesize DNA. However, less than 40% of these lymphocytes actually undergo mitosis while 35-90% of the newly synthesized DNA is excreted into the media. The release of DNA by the cells is selective since experiments with [(14)C]uridine indicate that RNA is not lost into the culture media. DNA excretion occurs under many culture conditions. The excreted DNA has an estimated molecular weight of 3 to 12 x 10(6) as determined by gel filtration on Sepharose 2B. It forms a single sharp peak at a density of 1.055 g/cm(3) when examined by sucrose density gradient centrifugation, suggesting that the DNA is complexed to protein or lipid.

Antigens↗
PubMed1971

Influence of pH on aggregation and protein binding of barbituric acid and amylobarbitone.

1. Cryoscopic methods indicated that barbituric acid exists in aqueous solution as a monomer. Amylobarbitone is a monomer at pH 8, but appears to be polymerized at pH 2. The size of the oligomers increases with drug concentration.2. Using a non-equilibrium dialysis technique supportive evidence for the monomeric form of barbituric acid and the polymerization of amylobarbitone was obtained. The degree of polymerization appeared to increase with fall in pH. Binding constants for these barbiturates with bovine serum albumin were derived, but in acid media no binding was observed.

Amobarbital↗
PubMed1971

The rapid induction by phytohemagglutinin of increased alpha-aminoisobutyric acid uptake by lymphocytes.

The effect of phytohemagglutinin (PHA) on the ability of human lymphocytes to transport the nonutilizable amino acid, alpha-aminoisobutyric acid (AIB) has been studied. PHA binds rapidly to plasma membrane receptor sites with half maximal binding requiring approximately 7.5 min. During the first 30 min after PHA addition to lymphocytes no change was detected in AIB transport, but then a linear increase in the initial rate of AIB transport occurred over the next 9 hr. Subsequently, the rate of AIB transport stabilized at a level 6-7 times greater than that found in control lymphocytes. The change in membrane function developed even when de novo protein synthesis was inhibited by 85-90% with puromycin or cycloheximide. However, the PHA effect did not occur when the lymphocytes were maintained at 4 degrees C. Studies of the kinetics of AIB uptake by control and PHA-treated lymphocytes demonstrated that PHA increases the V(max) of AIB uptake by 6-7-fold (0.7 mmumole AIB per 10(6) lymphocytes/15 min versus 0.1 mmumole per 10(6) lymphocytes/15 min) without affecting the Km (Michaelis constant) of the transport system (2mM in both cases).When fetuin was added to lymphocyte cultures to remove bound PHA, the PHA-induced increase in the rate of AIB uptake was arrested at the rate achieved during the time of prior incubation with PHA. This level of AIB transport persisted for at least 3 hr after 80% of the PHA was removed from the cell membrane. These data demonstrate that PHA rapidly induces a change in a lymphocyte cell membrane transport function, and that the continued presence of PHA on the cell membrane is required for the full stimulatory effect to be reached. The data do not distinguish between a direct action of PHA upon the lymphocyte membrane or the possibility that PHA slowly enters into the cell where it then exerts its effect.

Alpha-Globulins↗
PubMed1969

The influence of psychotropic drugs on aldole, mitochondrial malic dehydrogenase and Mg++na+K+ adenosine triphosphatase.

1. The experiment investigated the effects of psychotropic drugs on enzymes in vitro.2. Chlorpromazine inhibits mitochondrial malate dehydrogenase in concentrations of 1.4x10(-4)M and above. No effect was observed below this concentration.3. A sharp inflection in the [unk]/drug plot was also seen with chlorpromazine (1.4 x 10(-4)M), trifluoperazine (1 x 10(-5)M), prochlorperazine (1 x 10(-4)M), and amylobarbitone (8 x 10(-3)M) acting on rat brain (Na(+)-K(+)-) Mg(++)-ATPase and with chlorpromazine (10(-4)M) and imipramine (3 x 10(-4)M) acting on aldolase.

Adenosine Triphosphatases↗
PubMed1968

The effect of chlorpromazine on cerebral glucose, ATP, ADP, AMP and ATPase in the mouse.

1. Administration of chlorpromazine 10 mg/kg intraperitoneally to mice produced no alteration in cerebral adenosine triphosphate (ATP), adenosine diphosphate (ADP) or adenosine monophosphate (AMP). In these animals there was an increase in the glucose content of the supernatants of homogenates of liver and brain following acid hydrolysis.2. Chlorpromazine 40 mg/kg intraperitoneally did not affect Mg(++) activated adenosine triphosphatase (ATPase) activity in the brain.

Adenine Nucleotides↗
PubMedDate not supplied

An immunoelectron microscopic study of human placenta using three monoclonal antibodies.

An immunoelectron microscopic technique was used to analyse the distribution in term human placentae at the ultrastructural level of three antigens recognized by recently developed monoclonal antibodies. Two of the antigens (recognized by NDOG-1 and NDOG-2) were present only on the outer villous membrane of the syncytiotrophoblast. The other (HLA-A, B, C) was absent from syncytiotrophoblast and present on some capillary endothelial cells and on Hofbauer cells in the villous stroma.

Antibodies, Monoclonal↗