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Biomedical subjects

D Moss

Publications and source records attributed to D Moss.

At least 55 records · Page 3Linked to original sources
PubMed1991

Resistance to Leishmania major infection correlates with the induction of nitric oxide synthase in murine macrophages.

Inbred strains of mice differ considerably in their innate resistance to leishmanial infection. BALB/c mice are highly susceptible to cutaneous leishmaniasis caused by Leishmania major, whereas CBA mice are resistant. We now show that this resistance correlates with the ability of macrophages to synthesize nitric oxide (NO) following activation with interferon-gamma or tumor necrosis factor alpha. Furthermore, the larger amounts of NO generated by resistant macrophages are related to higher levels of NO synthase activity, a difference which is not attributable to the number or the affinity of the receptors for interferon-gamma on these cells. The level of NO synthesis by activated macrophages was also correlated to the resistance in a number of other inbred mouse strains tested; macrophages from the resistant B10.S, C57BL and C3H mice produced significantly higher levels of NO than the macrophages from the susceptible BALB.b and DBA/2 mice.

Amino Acid Oxidoreductases↗
PubMed1990

Redox-linked conformational changes in proteins detected by a combination of infrared spectroscopy and protein electrochemistry. Evaluation of the technique with cytochrome c.

We have developed a new technique for the study of redox-linked conformational changes in proteins, by the combination of two established techniques. Fourier-transform infrared spectroscopy has been used together with direct electrochemistry of the protein at a modified metal electrode surface. The technique has been evaluated with cytochrome c, because of its well-characterized electrochemistry and because the availability of X-ray crystallographic and NMR studies of both redox states of the protein provides a reference against which our data can be compared. In electrochemical control experiments, it was confirmed that the spectroelectrochemical cell design allows fast, accurate and reproducible control of the redox poise of the protein. The resulting reduced-minus-oxidized infrared difference spectra show the changes in the frequencies and intensities of molecular vibrations which arise from the redox-linked conformational change. In contrast to the absolute infrared spectra of proteins, such difference spectra can be sufficiently straightforward to allow interpretation at the level of individual bonds. A complete interpretation of the spectra is beyond the scope of the present paper: however, on the basis of the data presented, we are able to suggest assignments for all except one of the major bands between 1500 cm-1 and 1800 cm-1.

Animals↗
PubMed1989

The use of in vivo 2H NMR spectroscopy to investigate the effects of obesity and diabetes mellitus upon lipid metabolism in mice.

In vivo deuterium magnetic resonance spectroscopy was used to measure fat utilization rates in diabetic and non-diabetic obese and non-obese mice. Monosodium glutamate-treated mice were used as a model for obesity, and diabetes was induced by administration of streptozotocin. Deuterium levels were enhanced by addition of D2O to drinking water (10% v/v) for a period of 14 days. The deuterium magnetic resonance signals of the body water and adipose tissue were then monitored to measure the rate of deuterium loss from the body. The rates of fat utilization for obese mice were significantly lower (75%, p less than 0.05) (halflife, t1/2 = 113 +/- 13 days) than the rates for non-obese mice (t1/2 = 30.0 +/- 9.0 days). The induction of diabetes caused a large (90%) but proportionally similar increase in fat utilization for both groups of mice (obese, t1/2 = 11.0 +/- 5.2; non-obese, t1/2 = 3.0 +/- 0.9). The results suggest that the induction of diabetes in obese mice does not affect the utilization of fat as a metabolic fuel. These preliminary studies indicate that deuterium magnetic resonance spectroscopy may be a useful technique for non-invasive determination of the rates of fat utilization in vivo.

Animals↗
PubMed1989

Identification of H- and L-ferritin subunit binding sites on human T and B lymphoid cells.

Monoclonal antibodies to the H and L subunits of ferritin were used in indirect immunofluorescent studies to investigate the subunit specificity of ferritin binding to transformed T and B lymphoid cell lines. Pre-incubation of cells with recombinant H ferritin followed by antibodies to the H subunit produced a labelling pattern in which all cells showed strong fluorescent stippling. Corresponding experiments with liver ferritin and an antibody to the L subunit revealed that most cells were lightly stippled, but 3-5% of the cells were intensely labelled. These two labelling patterns were distinct as assessed by cross-blocking experiments with recombinant H and liver ferritins. These results imply that different binding sites exist for each subunit.

Antibodies, Monoclonal↗
PubMed1989

From the treatment of a nearly psychotic man: a Lacanian perspective.

In 'The unconscious', Freud's distinction between neurosis and psychosis rests upon a distinction in the functional utilization of word and thing representations in the two categories. This relation of word to thing parallels the relation of signifier to signified initially developed by Saussure and then taken up by Lacan in his re-reading and re-working of Freud. Lacan triangularizes Saussure's two-termed scheme by introducing the concept of the Father (The-Name-of..., The-Law-of..., The Paternal Function). The Father is a logical-structural term which permanently segregates signifier from signified and thus transforms erotic life from a search for the original 'real thing' to a represented substitute. Segments of a clinical narrative are presented to demonstrate this triangularity and to illuminate the particular volatility of that triangulated logical structure in near-psychotic states.

Adult↗
PubMed1986

Pseudoquotes in psychoanalytic interventions.

The syntactical structure of any psychoanalytic intervention is itself overdetermined. As such, when the syntax of an analyst's intervention seems out of the ordinary, it may mark a moment of particular difficulty. One syntactical form used frequently by psychoanalysts is a pseudoquote. In this form, the analyst speaks for the patient, uses the pronoun "I," as though he were, for the moment, the voice of the patient. Three such interventions are presented here from audio-recorded material. The interventions are examined in context, and some probable determinants are sketched. These determinants cluster around wishes and fears associated with "the difficult moment of self-other relatedness." This somewhat empirical portion of the paper is followed by a theoretical discussion in which the development of thought, speech, and the ego are related to the question of whether pseudoquotes actually serve the psychoanalytic process.

Humans↗
PubMed1985

Defective thermoregulatory thermogenesis in monosodium glutamate-induced obesity in mice.

We have studied thermoregulatory thermogenesis in mice rendered obese by neonatal administration of monosodium glutamate (MSG) and in saline treated controls. At 12 weeks of age MSG-treated mice maintained on a chow diet and housed at 24 degrees C, exhibited hypertrophy of brown adipose tissue (BAT) compared to controls (65% increase in wet weight and lipid content, no difference in DNA content). Acute cold exposure (4 degrees C for two hours) resulted in a significantly greater fall in core temperature in MSG-treated than control mice. After cold exposure to 4 degrees C for six hours, control animals mobilized BAT lipid whereas MSG-treated animals did not. Both groups showed comparable increments in oxygen consumption in response to exogenous norepinephrine. The above changes were qualitatively the same for both male and female animals. The following conclusions were reached: (1) MSG-treated mice have defective cold induced thermogenesis, indirect evidence suggests this results from impaired activation of thermogenic mechanisms in BAT; (2) the defect responsible for this lies extrinsic to BAT; and (3) the quantitative significance of defective thermoregulatory thermogenesis for the development of obesity in these mice is uncertain.

Adipose Tissue↗
PubMed1985

Cafeteria feeding promotes diet-induced thermogenesis in monosodium glutamate-treated mice.

We studied diet-induced thermogenesis (DIT) in cafeteria fed monosodium glutamate (MSG) and saline-treated mice. From 12 weeks of age MSG and saline-treated mice were fed a diet of either standard chow or a cafeteria diet of standard chow supplemented with chocolate or biscuits on alternate days for six weeks. There was a significant weight gain in cafeteria fed MSG-treated mice but not in cafeteria fed saline-treated mice. In cafeteria fed MSG-treated mice there was a significant increase in resting oxygen consumption. The response to exogenous norepinephrine was significantly increased in cafeteria fed saline-treated mice. The level of specific tritiated guanosine 5'-diphosphate binding to isolated mitochondrial fractions was significantly increased in both cafeteria fed MSG and saline-treated mice. It is concluded that (1) cafeteria feeding is capable of promoting DIT, within brown adipose tissue (BAT), in MSG-treated mice and (2) the mechanisms for the induction of thermoregulatory thermogenesis (TRT) and DIT are distinct since cold-induced TRT has previously been shown to be defective in MSG-treated mice.

Adipose Tissue, Brown↗
PubMed1985

Neuraminidase activity in Trypanosoma rangeli.

Supernatants of cultures and extracts of Trypanosoma rangeli readily release N-acetyl neuraminic acid from a variety of substrates. The activity in both supernatant and cell extract is precipitated between 30 and 50% ethanol, and between 40 and 70% ammonium sulfate. Fractionation of the culture supernatant by gel exclusion gives a single peak of neuraminidase activity of molecular weight 48 000. The culture supernatant releases sialic acid at different rates from the following substrates:fetuin, sialyllactose and orosomucoid but not from bovine submaxillary mucin and ovomucoid. The enzyme in the culture supernatant is also active against human erythrocytes of all ABO types. The enzyme showed an optimum pH of 5.0 for sialyllactose and erythrocyte substrates. Large amounts of the enzyme are preferentially secreted during growth in vitro.

Animals↗
PubMed1985

Comparison of nutrient calculation systems.

A set of 54 24-hour dietary recalls collected in 1975-1976 from males aged 35-57 years who were participating in a cardiovascular risk factor intervention program was submitted to three different nutrient calculation systems to investigate how much of a difference exists among systems in calculating nutrient intakes. The three computerized systems were of varying levels of sophistication. Among differences found, one system reported 1.4% more calories derived from polyunsaturated fat than the other two. For studies investigating the effects of dietary fat intake, this difference between systems may be important. Other significant group differences were seen for carbohydrate and alcohol. Although mean differences among the three systems were not great, dramatic differences were encountered when evaluating individual recalls. Nutrient intake data obtained from dietary recalls for individuals and for groups for whatever purpose are subject to the bias of the nutrient calculation system used. These biases should be considered when interpreting results, comparing results with other studies, and when developing treatment plans in the clinical setting. Recommendations for enhanced standardization include: 1) thorough descriptions in research reports of the particular system used; 2) exchange of standard menus between systems; 3) enhanced quality control of the coding process; 4) periodic updating of the nutrient data base to accommodate new food products and changes in composition of foods.

Adult↗
PubMed1985

High-resolution gradient polyacrylamide electrophoresis of isozymes of the mosquito, Aedes aegypti.

A procedure for high resolution electrophoresis of isozymes of the mosquito Aedes aegypti using nonlinear (2.5%-20%) polyacrylamide gradient gel slabs is described. Crude mosquito homogenates were electrophoresed on gradient and on homogeneous (7%) polyacrylamide gels and stained for esterase (EST), isocitrate dehydrogenase (IDH) and malate dehydrogenase (MDH). The resulting zymograms were compared to demonstrate the high resolving power of the polyacrylamide gradient gel system.

Aedes↗
PubMed1984

The molecular structures and interactions of bovine and human gamma-crystallins.

Knowledge of the three-dimensional structure of bovine gamma II-crystallin has provided the basis for building molecular models using computer graphics of two human gamma-crystallins, the sequences of which have recently been determined. The tertiary structures of these gamma-crystallins are predicted to be highly conserved. They have extensive networks of interacting charges on their surfaces, which may contribute to their thermodynamic stability and partially define the degree of water retention in the lens. The human crystallins appear to be more hydrophobic than the bovine molecule. All have arrangements of cysteine thiols which may be important as electron sinks and reserve redox potential in the normal lens but which may contribute to protein aggregation in cataract.

Amino Acid Sequence↗
PubMed1983

X-ray analysis of the eye lens protein gamma-II crystallin at 1.9 A resolution.

We report the X-ray structure analysis and refinement at 1.9 A resolution of calf gamma-II crystallin, a lens-specific protein. The sequence of Croft (1972) has been modified to give a polypeptide chain of 174 residues (cf. 165). The protein has a symmetrical, hierarchical structure of two globular domains each comprising two similar "Greek key" motifs, consecutive along the polypeptide chain, and related by a pseudo 2-fold axis. The two domains pack together with a single connection and are related by a further pseudo 2-fold axis which bisects the angle between the intra-domain dyads. Forty-two pairs of C alpha positions for the two most similar motifs have root-mean-square separation at best fit of 0.69 A. The N and C-terminal domains gave root-mean-square separation of 0.89 A for 82 pairs of C alpha atoms at best fit. In each domain the two Greek key motifs form a pair of four-stranded antiparallel beta-pleated sheets, each sheet composed of three stands from one motif and one from the other. The sheets pack together in a wedge shape, closed at the top by the loops connecting the third and fourth strands of each motif. The first two strands of each motif form an extended beta-hairpin which is folded on to the beta-sheet. The packing of each motif into the globular domains involves a staggered bilayer of side-chains between each pair of beta-sheets which does not preserve the pseudo 2-fold axes observed in the C alpha position topology. In the core of each domain there are interactions between polarizable aromatic groups and sulphur-containing residues which may contribute to stability and may also serve to protect aromatic side-chains from ultraviolet light damage in the lens. At the surface of the molecule over half the ionic side-chains are closely paired, which probably stabilizes the tertiary fold and may reduce the water bound. Crystal lattice interactions are described which may be similar to those occurring in vivo in the lens between crystallins. Seven cysteine residues have been identified in the structure and these may have a role in the thermodynamic stability of the molecule, its intermolecular interactions under the normal reducing conditions of the lens, and also in the aggregation and cross-linking which occur in some forms of cataract. Three of these residues, Cys18, Cys23 and Cys74, form a cluster in the N-terminal domain.(ABSTRACT TRUNCATED AT 400 WORDS)

Amino Acid Sequence↗