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Biomedical subjects

N Cox

Publications and source records attributed to N Cox.

At least 91 records · Page 5Linked to original sources
PubMed1987

Diagnosis of murine mycoplasmal infections by enzyme-linked immunosorbent assay (ELISA).

ELISA is the currently accepted method for screening rodent colonies for Mycoplasma pulmonis infection. While this assay has greatly improved mycoplasmal detection, it suffers from major defects. Cross-reactions with M. arthritidis are the major technical problem, and prevent definitive diagnosis. Current methods for obtaining a definitive diagnosis are accurate in about 80% of cases, and include ELISA testing for both organisms, immunoblot analysis, and blocking of the murine reaction with heterologous serum. Another technical difficulty is the inherent variability in the assay, which can be overcome by rigid quality control measures and careful attention to detail. The difficulties that arise from the natural history of mycoplasmal infection in barrier-maintained colonies, i.e., low incidence of infected animals and delayed antibody response in animals infected with low numbers of organisms, seriously limit the usefulness of the ELISA. While the assay can be extremely useful in screening breeding colonies and in eliminating mycoplasmas from such colonies, it cannot easily be used to screen potential sources of weanling animals for experimental use.

Animals↗
PubMed1984

Characterization of the rat mutant dystonic (dt): a new animal model of dystonia musculorum deformans.

An inherited neurological disorder characterized by sustained twisting movements during waking has been discovered in Sprague-Dawley rats. The mutation follows an autosomal recessive pattern of inheritance and has been named dystonic (dt). The rat mutants are indistinguishable from normal littermates in open field behavior and climbing activity prior to postnatal days 9 to 10. Clinical signs begin to appear on day 10 and include twisting of the axial musculature, hyperflexion of the trunk, self-clasping of forelimbs and hindlimbs, and poor placement of the limbs during locomotion. No morphological lesions of neural or non-neural tissues have been observed with routine light microscopy. Dystonic rats demonstrate significantly elevated cerebellar norepinephrine levels, although levels in other terminal fields of the locus ceruleus are similar to those of normal littermates. No differences in the pattern or density of noradrenergic innervation were apparent in cerebellar tissue from dt rats examined with histochemical fluorescence techniques. These mutants were less sensitive than unaffected littermates to the akinesic effects of the dopamine blocker haloperidol. However, striatal dopamine levels were not reliably different from normal in dt rats, and their response to the movement-stimulating effects of apomorphine appeared normal. These findings suggest the presence of biochemical disturbances in the extrapyramidal system of dt rats. The dt rat may provide a useful model for human dystonia musculorum deformans.

Aging↗
PubMedDate not supplied

Variation of apolipoprotein-B gene is associated with obesity, high blood cholesterol levels, and increased risk of coronary heart disease.

A random sample of 290 white men was examined for association between restriction fragment length polymorphism (RFLP) haplotypes (closely linked RFLPs on a single chromosome) of the apolipoprotein-B gene and serum levels of cholesterol, triglyceride, and high-density lipoprotein, obesity, smoking, alcohol consumption, and coronary heart disease. Haplotype or single RFLP frequencies differed significantly for obesity (p less than 0.005), serum cholesterol (p less than 0.005), and coronary heart disease (p less than 0.05), but for no other variable. Obesity was associated with haplotypes involving minimum PvuII and XbaI RFLPs are likely to be in linkage disequilibrium with nearby functional variation predisposing to obesity. Significant variation in serum cholesterol levels was associated with three functional alleles defined by MspI and EcoRI RFLP pairs (p less than 0.03). These RFLPs correspond to charged aminoacid variants at positions 3611 (arginine to glutamine) and 4154 (glutamic acid to lysine), which lie near the low-density-lipoprotein (LDL) receptor binding region of apolipoprotein-B. The three alleles showed stratification of serum cholesterol between low, normal, and high levels. Coronary heart disease was associated with minimum haplotypes involving XbaI and MspI RFLPs. Together these results suggest that inherited variations of the apolipoprotein-B gene, probably in the form of charged aminoacid substitutions, influence circulating cholesterol concentration, and that these and other functional variants of the apolipoprotein-B gene affect susceptibility to coronary heart disease and obesity.

Aged↗
PubMedDate not supplied

[Production of interleukin-2 in vitro and in vivo in elderly people, vaccinated with live and inactivated flu vaccines separately and combined].

Forty-three elderly individuals were immunized with Russian trivalent live cold-adapted influenza vaccine (LIV) and US trivalent influenza vaccine (IIV) administered separately or in combination. IL-2 production in vitro (in supernatants of cultures of lymphocytes stimulated with homologous viral antigens and PHA) and in vivo (in blood serum) and other factors of specific antiinfluenza immunity were compared. Vaccination of elderly subjects with commercial vaccines induced T-helper immunological memory, which manifests by increased secretion of IL-2 in vitro and in vivo. Simultaneous vaccination with LIV + IIV and revaccination (in 1 month) with LIV was the most effective method stimulating IL-2 production. The levels of IL-2 production in vitro were in good correlation with the secretion of this cytokin in vivo, lymph proliferation, and serum antibody production. No correlation between IL-2 production in vitro and the formation of local immune response (IgA in nasal swabs) was detected.

Aged↗
PubMedDate not supplied

[In vitro proliferative activity of lymphocytes from elderly persons after separate and combined immunization with live and inactivated flu vaccines].

Cellular (lymphocyte proliferation activity--LPA), humoral (serum antibodies), and secretory (IgA antibodies from the upper respiratory tract) immune responses were compared in 45 subjects aged 66-95 years, vaccinated with two influenza trivalent A(H1N1) + A(H3N2) + B vaccines: Russian live attenuated cold-adapted reassortant (LIV) and USA inactivated split-virus (IIV) vaccines. None of immunization protocols suppressed LPA after in vitro stimulation of cell culture with homologous virus antigens and nonspecific polyclonal mitogen (PHA). Simultaneous LIV + IIV vaccination was the most effective method of immunization, inducing humoral, secretory, and cellular immunity. LIV more actively than IIV stimulated the lymphoproliferative immune responses. Fluctuations in the mean values of cellular, humoral, and secretory immunity were in good correlation over the entire period of observation (19 weeks). Analysis of individual immune responses showed that a significant increase in quantitative parameters of LPA was observed only in 39-52% vaccinees.

Aged↗
PubMedDate not supplied

[Analysis of the antigenic structure of influenza A/USSR/90/77 virus hemagglutinin].

Evolution of the antigenic structure of influenza virus hemagglutinin with the antigenic formula HA1 was studied by the determination of the capacity for interaction with monoclonal antibody and aminoacid substitutions in the protein. Consecutive changes in protein epitopes were found in isolates accumulating from the time of isolation of H1 influenza viruses in 1977.

Amino Acid Sequence↗