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Biomedical subjects

D Nelson

Publications and source records attributed to D Nelson.

At least 271 records · Page 15Linked to original sources
PubMed1984

Suppressor cell number and function in alopecia areata.

Several values of immunologic function were studied and correlated with disease activity and extent in 14 patients with alopecia areata, alopecia totalis, or alopecia universalis and in a concurrently studied age- and sex-matched control group. As compared with the control group, the patients showed a significantly increased incidence of autoantibody formation, increased concanavalin A-induced suppression of the normal lymphocyte response to mitogens, an increased proportion of suppressor-cytotoxic cells in the peripheral blood, and a decrease in the absolute B-cell count. Absolute total T-cell counts, quantitative serum immunoglobulin determinations, and lymphocyte proliferation after exposure to the mitogens--concanavalin A, phytohemagglutinin, and pokeweed--and to tetanus antigen were comparable for both groups. Neither the percentage of concanavalin A-induced suppression of the normal lymphocyte response to mitogens nor the helper-suppressor ratio correlated significantly with the extent of hair loss. However, patients, particularly those who demonstrated spontaneous regrowth of hair, had increased concanavalin A-induced suppression in conjunction with an increase in the proportion of peripheral suppressor cells.

Adolescent↗
PubMed1983

A recording viscometer for assaying mammalian collagenase.

A recording viscometer for monitoring the action of mammalian collagenase on soluble collagen is described. For this system, where only one peptide bond is cleaved per subunit, it is shown theoretically that the decrease in viscosity is proportional to the fraction of molecules cleaved. Experimental confirmation was obtained by parallel monitoring of hydrolysis by using the fluorescamine assay of liberated amino groups. The initial velocity of reaction is proportional to substrate concentration and enzyme concentration.

Collagen↗
PubMed1983

Inhibition of SV40-induced cellular DNA synthesis by microinjection of monoclonal antibodies.

The region of the SV40 large T-antigen molecule recognized by a panel of monoclonal antibodies has been determined using hybrid Adeno-SV40 viruses, and manual microinjection of cloned deletion mutants. In addition, an investigation was made of how monoclonal antibodies microinjected into the nucleus can affect the ability of the T-antigen coding gene to stimulate cell DNA synthesis. The monoclonal antibody Pab 14, that recognized the -COOH terminal half of large T, was comicroinjected into quiescent cells together with plasmid pCl-1. This plasmid contains only that part of the T-antigen coding gene that extends from nucleotide residue 120, counterclockwise to nucleotide residue 4002, and makes a truncated T antigen 33,000 in molecular weight and missing the last 435 amino acids on the -COOH terminal side. Monoclonal antibody Pab 14 did not inhibit the stimulation of cellular DNA synthesis caused by microinjection of pCl-1, although it did inhibit cell DNA synthesis induced by microinjection of pSV2G, a recombinant plasmid that contains the entire T-antigen coding gene of SV40.

Adenoviruses, Human↗
PubMed1983

Surveillance for California encephalitis group virus illness in Wisconsin and Minnesota, 1978.

During the summer and fall of 1978, active surveillance for encephalitis in southwestern Wisconsin and southeastern Minnesota resulted in the detection of the largest number of cases of California encephalitis group (CEG) virus infections ever documented in that region, where CEG virus is known to be endemic. A total of 75 laboratory-confirmed and eight presumptive cases of CEG virus infections were identified as a result of serologic testing completed in the Wisconsin and Minnesota State Laboratories. Cases included 46 residents of Wisconsin, 25 of Minnesota, 10 residents of Iowa and two from Illinois. The outbreak peaked during the last half of August and the first half of September. Eighty percent of patients were less than 10 years of age; only one case was documented in an adult (greater than or equal to 18 years). The clinical picture in patients ranged from mild aseptic meningitis to encephalitis with coma; convulsions occurred in 31% (22/72) of patients. One patient, a 3-year-old girl, died. The high incidence of infection detected in this investigation may be representative of the endemic incidence of CEG illness in the region and suggests that CEG infections in children residing in endemic areas in Wisconsin and Minnesota may be a greater public health problem than previously recognized.

Adolescent↗
PubMed1983

Identification of a human pancreatic duct tissue-specific antigen.

Antiserum raised against a pancreatic duct mucin was absorbed with type AB red blood cells and used in the indirect immuno-glucose oxidase procedure to examine tissue specificity. All mucin-producing organs were stained by this antiserum. Absorption of the antiserum with mucinous ovarian cystadenocarcinoma fluid eliminated generalized mucin staining, and only pancreatic ducts and colonic goblet cells were positive. Further absorption with purified colonic mucin revealed a pancreatic duct tissue-specific determinant(s). This tissue-specific determinant(s) was detected in the RIP-1 and RIP-2 human pancreatic adenocarcinomas carried as xenografts in athymic nude mice. Because the majority of pancreatic adenocarcinomas are believed to arise from ductal tissue, pancreatic duct mucin may have a useful role as a marker in detection and differential diagnosis.

Animals↗
PubMed1983

Erythrocyte contents of electrolytes (Na, K, Mg, Zn) in healthy male controls and offspring to established hypertensive patients: a follow-up study.

Erythrocyte sodium, potassium, zinc and magnesium were measured in 56 male offspring to essential hypertensive patients and compared with 46 matched controls. The same parameters were measured again 4-6 months apart in 31 offspring and eight controls. Intracellular sodium was significantly higher in offspring (P less than 0.001). There was a highly significant correlation between the two intra-individual measurements of intracellular sodium, potassium and zinc but not for magnesium. Sodium in erythrocytes is probably an indicator of the activity of the sodium-pump and could possibly be used as a genetic marker in the future investigations of individuals with heredity for severe, essential hypertension.

Adolescent↗
PubMed1982

Protein antigens of the RNA-protein complexes detected by anti-SM and anti-RNP antibodies found in serum of patients with systemic lupus erythematosus and related disorders.

Evidence has been obtained previously indicating that the antigens reacting with the anti-Sm and anti-RNP sera are present as a large complex, and similar protein bands are obtained with both types of sera. Inthe present study, it proved possible to break up this complex using SDS treatment before immunoprecipitation. After such treatment, different protein bands were immunoprecipitated by the two antisera; Sm determinants resided, at least partially, in a 19-kd protein. Sequential immunoprecipitation with and without prior SDS treatment provided further evidence for these specificities and suggested that two classes of particles exist in different tissues, one containing proteins immunoreactive with the Sn and RNP antisera and the other containing proteins immunoreactive only with the Sm antisera. The latter particle contained all the bands seen with the first type except for the absence of the 19-kd band. Nitrocellulose blot analyses confirmed the assignment of the 25- and 16-kd polypeptides to Sm antigenic determinants; analyses for RNP proved les informative by this technique. Some differences in the banding patterns were obtained using cells from different species: the 25-kd Sm band was usually double in human cells and single in rat and rabbit tissue. Methods of extraction also caused some differences which was especially true for the rabbit thymus extract widely used for Sm and RNP studies. Additional immunoreactive bands at 68 and 70 kd also were detected when the Sm and RNP antisera were used in nitrocellulose blot analyses. Furthermore, evidence was obtained for a number of other antibodies in lupus sera which have not as yet been detected by serological methods.

Antibody Specificity↗
PubMed1982

Coulometric and potentiometric evaluation of the redox components of cytochrome c oxidase in situ.

A new coulometric-potentiometric titration cuvette is described which permits accurate measurements of oxidation-reduction components in membranous systems. This cuvette has been utilized to measure the properties of cytochrome c oxidase in intact membranes of pigeon breast muscle mitochondria. The reducing equivalents accepted and donated by the portion of the respiratory chain with half-reduction potentials greater than 200 mV are equal to those required for the known components (cytochrome a3 and the high-potential copper plus cytochrome a, 'visible copper', cytochrome c1, cytochrome c, and the Rieske iron-sulfur protein). Titrations in the presence of CO show that formation of the reduced cytochrome a3-CO complex requires two reducing equivalents per cytochrome a3 (coulometric titration). Potentiometric titrations indicate (Lindsay, J.G., Owen, C.S. and Wilson, D.F. (1975) Arch. Biochem. Biophys. 169, 492--505) that both cytochromes a3 and the high-potential copper must be reduced in order to form the CO complex (n = 2.0 with a CO concentration-dependent half-reduction potential, Em). By contrast, titrations in the presence of azide show that the Em value of the high-potential copper is unchanged by the presence of azide and thus azide binds with nearly equal affinity whether the copper is reduced or oxidized.

Animals↗