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Biomedical subjects

J Nagel

Publications and source records attributed to J Nagel.

At least 73 records · Page 4Linked to original sources
PubMed1982

Interaction of staphylococcal protein A in enzyme-linked immunosorbent assays for detecting staphylococcal antigens.

ELISA procedures for detecting staphylococcal antigens may be subject to interference by reactions between staphylococcal protein A (SPA) and IgG molecules. It was found that rabbit IgG reacted with SPA, both in the native state and after conjugation with peroxidase. Sheep IgG, however, did not react with SPA if conjugated with peroxidase. Peroxidase conjugated SPA reacted with rabbit IgG but not with sheep IgG. These results demonstrate that the source of IgG used in an ELISA system is of major importance to correct quantitation of staphylococcal antigens.

Animals↗
PubMed1982

Measurement of O6-ethyldeoxyguanosine and N-(deoxyguanosin-8-yl)-N-acetyl-2-aminofluorene in DNA by high-sensitive enzyme immunoassays.

Antibodies raised in rabbits against the bovine serum albumin conjugates of O6-ethylguanosine and N-(guanosin-8-yl)-N-acetyl-2-aminofluorene have been used to develop a high-sensitive enzyme-linked immunosorbent assay (HS-ELISA) for the quantification of adducts in DNA modified by ethylating agents and N-acetyl-2-aminofluorene. Linear dose-response relations were obtained in the non-competitive HS-ELISA between 0.5 fmol and 50 fmol O6-ethyldeoxy-guanosine per 2.8 microgram DNA, and between 0.1 fmol and 20 fmol N-(deoxyguanosin-8-yl)-N-acetyl-2-aminofluorene per 0.8 microgram DNA. The sensitivity of an ultrasensitive radioimmunoassay was in the same order of magnitude. Modification levels as low as 0.1 mumol of adduct/mol DNA-nucleotides (1: 10(7)) can be detected by each assay.

2-Acetylaminofluorene↗
PubMed1982

Comparison of the induction of immunoglobulin M and G antibodies in mice with purified pneumococcal type 3 and meningococcal group C polysaccharides and their protein conjugates.

The nature and kinetics of the serum antibody response to pneumococcal type 3 and meningococcal group C polysaccharides and their protein conjugates were studied in mice. Bovine serum albumin and diphtheria and tetanus toxoids were used as carrier proteins. The purified polysaccharides induced only immunoglobulin M (IgM) antibodies in thymus-bearing as well as congenic athymic (nude) mice. The polysaccharides covalently conjugated to proteins produced IgM and IgG antibodies in normal mice, but only IgM antibodies in nude mice. A second dose of the polysaccharide-protein conjugates resulted in a booster effect in the IgG response to the polysaccharides. Moreover, memory B-cells, generated after a primary injection with the polysaccharide-protein conjugates, could be triggered to the production of IgG antibodies after a second injection with the pure polysaccharides alone. These data indicate that the antibody response to the pure polysaccharides is thymus independent and that this response can be changed into a thymus-dependent response by covalent conjugation of the polysaccharide to a thymus-dependent protein.

Animals↗
PubMed1982

Immunoglobulin M and G antibody responses and persistence of these antibodies in adults after vaccination with a combined meningococcal group A and group C polysaccharide vaccine.

Adult volunteers were injected with a combined meningococcal group A and group C polysaccharide vaccine. Immunoglobulin M (IgM) and IgG antibody levels against both polysaccharides were measured in serum samples taken 14 days as well as 3 years after vaccination. For both group A and group C polysaccharides, the IgM and IgG antibody levels at 14 days postvaccination were positively related. The IgM-to-IgG antibody ratio at 14 days postvaccination was an indicator for the persistence of both IgM and IgG antibodies during the next 3 years; a high ratio meant a short persistence, whereas a low ratio was associated with a long persistence.

Adult↗
PubMed1982

Immunological detection and quantification of the reaction products of 2-acetylaminofluorene with guanine in DNA.

Rabbits were immunized with N-(guanosin-8-yl)-N-acetyl-2-aminofluorene bound to bovine serum albumin. The presence of specific antibodies was determined in a radioimmunoassay by competing N-([5'-3H]-guanosin-8-yl)-N-acetyl-2-aminofluorene (specific radioactivity, 25 Ci/mmol) as tracer against various carcinogen-modified and normal DNA components. Highly specific antibodies were obtained (affinity constant, 6.0 X 10(9) l/mol) and have been employed in a sensitive radioimmunoassay to determine N-(deoxyguanosin-8-yl)-N-acetyl-2-aminofluorene directly in enzymatic hydrolysates of DNA modified with N-acetoxy-N-acetyl-2-aminofluorene. In a similar fashion, the modified nucleoside could be detected in hydrolysed rat liver DNA following administration of N-acetyl-2-aminofluorene, with a detection limit of one carcinogen-modified deoxyguanosine moiety per 10(6) deoxynucleotides in 150 micrograms of DNA.

2-Acetylaminofluorene↗
PubMed1982

[Regulation of erythropoiesis in the rat fetus: role of spleen and bone marrow in case of deficiency of hepatic erythropoietic activity].

At the end of intra-uterine life in the rat, hepatic erythron evolution is governed by corticosteroids and it is experimentally possible to prematurely deprive the foetus of a large part of its hepatic erythropoietic tissue by inflicting repeated stress in the pregnant animal. This experimentally induced deficiency of the hepatic erythron leads to an anticipated erythroid activity in the bone marrow. Splenectomy in such fetuses has shown that the spleen does not play a major role in producing circulating anucleated erythroid cells before term.

Animals↗
PubMed1981

Factor structure of the Faschingbauer Abbreviated MMPI (FAM) in a psychiatric population.

Factor analysis of the Faschingbauer Abbreviated MMPI (FAM) identified factors of Absence of Distress, Depression, Low Morale, Feminine Interests, Somatization, and Extroversion. These results are consistent with previous MMPI factoranalytic studies, with the first factor being a reflected factor of major psychopathological disturbance. This reflected factor is explained as a function of the elimination of clinically invalid profiles from the analysis. Implications concerning standard profile selection procedures are discussed in light of these results.

Adult↗
PubMed1981

Immunity to diphtheria, pertussis, tetanus, and poliomyelitis in children with acute lymphocytic leukemia after cessation of chemotherapy.

Antibody titers to diphtheria, pertussis, tetanus, and poliomyelitis (types I to III) were measured in previously vaccinated children with acute lymphocytic leukemia in remission after cessation of therapy. The response to revaccination one year after therapy was stopped was also studied. The patients' antibody titers were compared with those of healthy children, matched for age and sex. Two groups of patients were studied: one group (group A, N = 30) was given two drugs (6-mercaptopurine, methotrexate); the other group (group B, N = 19) was given three drugs (6-mercaptopurine, methotrexate, and cyclophosphamide) for maintenance treatment. In general, the patients' antibody titers were lower than those of healthy children, but in most patients they were still at levels considered to be protective. No significant differences in antibody levels between the two patient groups were found. A spontaneous rise in antibody titers in the first year after termination of therapy was not observed. After revaccination the rise in antibody titers was correlated with preexisting antibody titers in the same way in patients as in healthy children, and the antibody titers in patients and in healthy control subjects were on roughly the same level.

Adolescent↗
PubMed1981

Early erythropoiesis in foetal rat bone marrow: evidence for a liver-to-bone marrow relay.

Erythropoietic activity of foetal rat femoral marrow was examined during the last four days of intra-uterine life. Insignificant at day 18, it develops slowly thereafter until birth. In the non-suckled neonate (not older than two hours), it appears notably enhanced. In order to test the potential of the foetal marrow to develop precocious or increased erythropoiesis, the activity of the erythropoietic organ predominant at this time, the liver, was altered by modifying the level of circulating corticosteroids, which govern its function. Maturation and involution of the hepatic erythron wee prevented by corticosteroid deprivation of the foetus (maternal adrenalectomy and foetal hypophysectomy). Precocious maturation and exhaustion of the hepatic erythron was induced by submitting foetuses to corticosteroids excess from day 14. Both corticosteroid deprivation and excess increase the erythropoietic activity of the femoral marrow. This activity can reach and even exceed by day 20 of intrauterine life that in neonatal marrow. Foetal hepatic erythron misfunction can therefore initiate and stimulate bone marrow erythropoiesis. The study of circulating red blood cells demonstrates that : (1) anaemia initiates medullary erythropoietic activity; (2) this anaemia is largely corrected by the bone marrow. The regulatory mechanism is presumably erythropoietin mediated.

Adrenalectomy↗
PubMed1978

Antitoxin responses in the elderly to tetanus-diphtheria (TD) immunization.

A high per centage of reported cases of tetanus and diphtheria in the United States occurs in persons over 60 years old. The sera of 69 elderly persons, mean age 80 years, were tested for prevalence of tetanus and diphtheria antibodies, and only 51% and 59%, respectively, had protective levels (greater than or equal to .01 AU/ml). In a prospective study 27 elderly volunteers were given 0.5 ml tetanus-diphtheria (Td) toxoid twice, seven months apart. Before toxoid 26% and 59% of persons had protective antitoxin levels against tetanus and diphtheria. After one dose the per cent protected rose to 42 and 88. After the second dose all persons immunized had protective levels. No subjects had significant side effects after either dose. These data demonstrate that many elderly persons lack protection against tetanus and diphtheria and document that two doses of Td toxoid would confer immunity to virtually all such persons.

Aged↗
PubMed1978

A two-dose schedule for immunization of infants using a more concentrated DPT-vaccine.

In a controlled field-trial in infants in the Philippines, a two-dose schedule with an interval of 6 months between injections using a concentrated adsorbed DPT-vaccine was evaluated. The serologic response against the three components in the vaccine was satisfactory, whereas the side-effects in the concentrated vaccine group did not differ from those observed in a control DPT group. After two injections, the coverage percentage with DPT-vaccine was shown to be higher than 70%. Two implications of the introduction of the two-dose DPT-immunization schedule are discussed, i.e. (a) the possibility of using it as the nucleus of a complete schedule including immunization against poliomyelitis, BCG, smallpox and measles, and (b) the consequences which the interval of 6 months might have on the epidemiological spread of B. pertussis infections.

Age Factors↗