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Biomedical subjects

T A Anderson

Publications and source records attributed to T A Anderson.

At least 37 records · Page 2Linked to original sources
PubMed1993

Immunoreactive and receptor-active insulin-like growth factor-I (IGF-I) and IGF-binding protein in blood plasma from the freshwater fish Macquaria ambigua (golden perch).

The presence of insulin-like growth factor-I (IGF-I)-related molecules and IGF-binding factors in blood from golden perch, Macquaria ambigua, an Australian native freshwater fish, was investigated. Serum was acidified to dissociate IGF and IGF-binding protein complexes that might be present, and fractionated by size-exclusion high-performance liquid chromatography at pH 2.8. Fractions were neutralized and their activities assessed by (i) an immunoassay for mammalian IGF-I which also detects chicken IGF-I but in which all known forms of IGF-II react very poorly, (ii) a receptor assay for IGF-II in which all known forms of IGF-I react poorly, and (iii) a type-I IGF receptor assay in which mammalian IGF-I and IGF-II polypeptides are amost equivalent. No IGF-II-like activity was detected. Three peaks of IGF-I-like activity were detected by IGF-I immunoassay and type-I IGF receptor assay. The major peak of activity was similar in molecular size to human IGF-binding protein-3, 45-55 kDa ('large IGF'), and a minor peak of activity which was similar in size to mammalian IGFs, 7.5 kDa. A third peak of activity was observed eluting at a time which indicates that it is a smaller molecule than any previously described IGF. The large IGF was temperature-sensitive, but was not a binding protein for 125I-labelled human IGF-I (hIGF-I). This material therefore was able to bind to anti-hIGF-I antibodies and to human type-I IGF receptors, and may represent the fish equivalent of mammalian prepro-IGFs.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Medicine for a sick immunization system.

The United States has recently experienced a rise in the incidence of measles and other preventable infectious diseases. Studies have linked the problem to a growing number of inadequately vaccinated preschoolers. The Minnesota Department of Health estimates that only 61.4% of the state's 2-year-olds have completed the basic primary series on schedule. Coverage rates are worse in the Twin Cities, where the number of poor and minority "at-risk" children has skyrocketed in the last 10 years. Two different assessments in St. Paul revealed that only 24% to 32% of the 2-year-olds in the survey populations had received the basic series of immunizations. Public and private health care providers need to work together to eliminate barriers to immunization.

Child, Preschool↗
PubMed1991

Induction of self-tolerance in T cells but not B cells of transgenic mice expressing little self antigen.

Self-tolerance to a transgene-encoded protein, hen egg lysozyme, was examined in the T and B cell repertoires of a series of lines of transgenic mice that expressed different serum concentrations of soluble lysozyme. T cells were tolerant in all lines in which lysozyme was expressed irrespective of the antigen concentration, whereas B cell tolerance did not occur when the serum lysozyme concentration was less than 1.5 nanograms per milliliter (0.1 nM). Induction of elevated transgene expression could restore B cell tolerance. These findings support the hypothesis that autoimmune disease may in some instances arise through a bypass of T cell tolerance.

Animals↗
PubMed1991

Crystallization and preliminary analysis of telokin, the C-terminal domain of myosin light chain kinase.

Telokin, an acidic protein related to the C-terminal portion of smooth muscle myosin light chain kinase from turkey gizzard has been crystallized in a form suitable for a high-resolution diffraction analysis. The crystals were grown from solutions of polyethylene glycol 8000 using the hanging-drop vapor diffusion method. They belong to the trigonal space group P3(1)21 or P3(2)21 with cell parameters a = 64.0 A, c = 59.4 A and diffract to at least 2.7 A resolution.

Animals↗
PubMed1990

Microbial degradation of trichloroethylene in the rhizosphere: potential application to biological remediation of waste sites.

The possibility that vegetation may be used to actively promote microbial restoration of chemically contaminated soils was tested by using rhizosphere and nonvegetated soils collected from a trichloroethylene (TCE)-contaminated field site. Biomass determinations, disappearance of TCE from the headspace of spiked soil slurries, and mineralization of [14C]TCE to 14CO2 all showed that microbial activity is greater in rhizosphere soils and that TCE degradation occurs faster in the rhizosphere than in the edaphosphere. Thus, vegetation may be an important variable in the biological restoration of surface and near-surface soils.

Biodegradation, Environmental↗
PubMed1983

Stimulation of neuronal Na+, K+-ATPase by calcium.

The effect of calcium on ATP-phosphohydrolase activity of rat brain homogenates has been investigated. In both the presence and absence of the chelating agent EDTA, free calcium within the concentration range 1.2 x 10(-7) to 5.0 x 10(-4) moles/l consistently affected only the activity of Na+, K+-ATpase; the activities of Mg2+-ATPase and Na+-ATPase were essentially unchanged by Ca2+; Ca2+-ATPase could not be demonstrated. In either the presence or absence of EDTA, concentrations of free-Ca2+ above 3 x 10(-6) moles/l caused an inhibition of Na+,K+-ATPase activity. In the presence of EDTA, concentrations of free-Ca2+ below 3 x 10(-6) moles/l were ineffective at altering Na+, K+-ATPase activity but, in the absence of EDTA, free-Ca2+ in this concentration range caused a marked stimulation of the enzyme. Evidence is presented to show that the stimulation of Na+, K+-ATPase by calcium is modulated by the regulatory protein calmodulin. Since the stimulation occurs over the range of concentrations at which calcium would be expected to be encountered within the cell, it is suggested that this is the major physiological effect of calcium on Na+, K+-ATPase.

Animals↗
PubMed1981

Ruthenium red-insensitive calcium transport in ascites-sarcoma 180/TG cells.

1. Ruthenium Red-insensitive Ca2+ transport in the mouse ascites sarcoma 180/TG is enriched in a 'heavy' microsomal fraction (microsomes) sedimented at 35 000 g for 20 min. The subcellular distribution of this Ca2+ transport differed from that of Ruthenium Red-sensitive Ca2+ transport and (Na+ + K+)-dependent ATPase activity, but was similar to that of glucose 6-phosphatase. 2. The affinity of this transport system for 'free' Ca2+ is high (Km approx. 6 microM) and that for MgATP somewhat lower (Km approx. 100 microM). Ca2+ transport by the tumour microsomes, by contrast with that by liver microsomes, was greatly stimulated by low concentrations of P1. 3. Although incubation of intact ascites cells with glucagon led to an increase in intracellular cyclic AMP, no stable increase in the initial rate of Ca2+ transport in the subsequently isolated 'heavy' microsomes could be detected as in similar experiments carried out previously with rat liver cells. Reconstitution experiments suggest that a deficiency exists in the tumour microsomal membrane such that an action of glucagon that is normally present in rat liver microsomes is not evoked.

Animals↗
PubMed1980

Effect of feeding frequency on growth and body composition of gastrostomized rat pups.

Two groups of rat pups were gastrostomized at 24 hours of age and formula-fed each hour or once every 6 hours a daily intake equal to 33% of their body weight. They were killed at age 5 to 7 days when body weight had reached twice that at time of gastrostomy; organ weights, body composition and hepatic activity of glucose-6-phosphate-dehydrogenase (G-6-PD) and alpha-glycerophosphate dehydrogenase (alpha-GPD) were determined. The stomach, small intestine, liver and spleen of pups fed 4 times each day were significantly larger than those of pups fed hourly. Food efficiency (gain/kcal) of pups fed each hour was significantly greater than that of pups fed every 6 hours; however, because pups fed each hour gained more water and less fat, an estimate of the percentage of energy intake utilized for growth was significantly less for these animals than for those fed every 6 hours. Concentration of calcium was greater and concentration of sodium was less in the carcasses of pups fed each hour than in the carcasses of pups fed 4 times daily. Total liver activities of G-6-PD and alpha-GPD were significantly less in pups fed each hour but the activity of these enzymes expressed per milligram of liver protein did not differ significantly between the two feeding groups.

Animals↗