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Results for “quantitative complementation”

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At least 19 recordsLinked to original sources
PubMed2004

How good are quantitative complementation tests?

Several recent studies have used quantitative complementation tests to identify relatively short chromosome regions that contain genes that influence life span and to screen for candidate life-span genes in flies. The methodology and logic of quantitative complementation tests are described. Arguments are presented that suggest that these tests may be misleading because there is a substantial, but unknown, likelihood of false positive results. The arguments are supported by the published results of quantitative complementation tests.

Animals↗
PubMed1980

A large-scale radiometric micro-quantitative complement fixation test for serum antibody titration.

A micro-quantitative complement fixation (CF) procedure based on 51Cr release is described. The method employs 50% hemolysis as end point and the alternation equation to calculate the amount of complement involved in the hemolytic reaction. Compared to the conventional CF tests, the radiometric procedure described here is very precise and consistently reproducible. Also, since only 3 4-fold dilutions of sera are used for the titration of antibodies over a wide range of concentrations, the test is very concise and is economical to perform. Its format is amenable to automation and computerization. This radiometric CF procedure is thus most useful for large-scale immunological research and epidemiological surveillance studies.

Animals↗
PubMedDate not supplied

[Detection of new antigens, induced by retrovirus D, by a quantitative complement fixation micromethod using radioactive chromium].

The additional evidence of the existence of antigenic differences between the early virus-induced antigen and structural retrovirus D antigens as well as antigens from human fetus normal tissues was obtained by quantitative complement fixation micromethod using radioactive chromium (51Cr-CFT). In examinations of 13 specimens of cancer tumours and fibroadenomas of the female mammary glands the new antigen was found in 8 cases, including 4 cancer tumours where this antigen could not be detected by the conventional CFT.

Adenofibroma↗
PubMed1966

Murine leukemia viruses: antigenic studies by quantitative complement fixation.

The murine leukemia viruses of Rauscher and Friend, derived from plasnma of infected Balb/c mice, was purified. Their antigenic relationship was studied by quantitative complement-fixation reactions with the virion antigen and homologous antiserums. The complement-fixation curves observed in cross-reactions indicated close antigenic similarity between these two leukemia viruses. Highly purified viral preparations contained detectable amounts of host antigens.

Animals↗
PubMed1971

A carotenogenic enzyme aggregate in Phycomyces: evidence from quantitive complementation.

Wild-type Phycomyces blakesleeanus accumulates beta-carotene, while the mutant strain C2 is unable to synthesize carotenoids, and the mutant strain C9 accumulates lycopene. Heterokaryons containing a proportion, p, of C2 nuclei and (l - p) of C9 nuclei accumulate lycopene, gamma-carotene, and beta-carotene in the relative amounts (l - p), p(l - p), and p(2), respectively, for different values of p. It is shown that these results are expected from the operation of a carotenogenic enzyme aggregate that works as an assembly line and contains two copies of a cyclase, which is defective in strain C9, as well as other enzymes.

Carotenoids↗
PubMed2000

Focus groups: a qualitative method complementing quantitative research for studying culturally diverse groups.

CONTEXT: Focus groups are becoming an important method for conducting qualitative research in health care. This strategy enables information to be gathered on the perceptions, beliefs, and values of a group's participants and is particularly well suited to addressing cultural characteristics that impact on a population's health status. As nations become more culturally diverse, qualitative research will likely play a growing role in helping health professions educators develop appropriate educational programs and in helping researchers better understand the needs of minorities and other vulnerable populations who are experiencing disparities in health care. OBJECTIVES: The purposes of this paper are to introduce the usefulness of a qualitative research strategy as an adjunct to quantitative survey research, and to describe briefly how researchers and educators at the Charles R. Drew University of Medicine and Science (Drew) have utilized this strategy when conducting combined qualitative and quantitative research. DISCUSSION: Focus group research has been successfully used to develop culturally adapted surveys, to develop educational programs, and to conduct needs assessments at Drew, which serves a culturally diverse urban population.

Journal Article↗
PubMed2006

Plasma Epstein-Barr viral deoxyribonucleic acid quantitation complements tumor-node-metastasis staging prognostication in nasopharyngeal carcinoma.

PURPOSE: To evaluate the effect of combining circulating Epstein-Barr viral (EBV) DNA load data with TNM staging data in pretherapy prognostication of nasopharyngeal carcinoma (NPC). PATIENTS AND METHODS: Three hundred seventy-six patients with all stages of NPC were studied. Pretreatment plasma/serum EBV DNA concentrations were quantified by a polymerase chain reaction assay. Determinants of overall survival were assessed by multivariate analysis. Survival probabilities of patient groups, segregated by clinical stage (I, II, III, or IV) alone and also according to EBV DNA load (low or high), were compared. RESULTS: Pretherapy circulating EBV DNA load is an independent prognostic factor for overall survival in NPC. Patients with early-stage disease were segregated by EBV DNA levels into a poor-risk subgroup with survival similar to that of stage III disease and a good-risk subgroup with survival similar to stage I disease. CONCLUSION: Pretherapy circulating EBV DNA load is an independent prognostic factor to International Union Against Cancer (UICC) staging in NPC. Combined interpretation of EBV DNA data with UICC staging data leads to alteration of risk definition of patient subsets, with improved risk discrimination in early-stage disease. Validation studies are awaited.

Biomarkers, Tumor↗