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Biomedical subjects

C French

Publications and source records attributed to C French.

At least 37 records · Page 2Linked to original sources
PubMed1996

Stability of free prostate-specific antigen in serum samples under a variety of sample collection and sample storage conditions.

OBJECTIVES: Four studies were conducted to characterize the stability of free and total prostate specific antigen (PSA) under various sample collection and storage conditions. METHODS: In the first study, fresh blood from 11 patients was drawn and allowed to clot at room temperature (RT). Serum was prepared by centrifugation 1, 3, 5, or 8 hours after the blood draw and tested to determine the free and total PSA levels. In the second study, serum specimens from 12 individuals were stored at RT or 4 degrees C and were tested on days 0, 1, 2, and 7. In the third study, four fresh serum samples were subjected to five freeze-thaw cycles and tested after each cycle. In the fourth study, 29 fresh samples were aliquoted, frozen at -20 degrees C or -70 degrees C, and monitored for long-term stability. RESULTS: Approximately 1% of the free PSA was lost per hour of clotting time. Between 2% and 3% of the free PSA was lost per day of storage at 4 degrees C or 23 degrees C. About 0.9% of the free PSA was lost per month of storage at -20 degrees C compared with about 0.4% per month at -70 degrees C. Total PSA appeared to be stable throughout these studies. CONCLUSIONS: Our results suggest that routine serum preparation and refrigerated storage of samples for up to 24 hours is acceptable for the measurement of both free and total PSA. Samples that are to be retained for longer than 24 hours should be frozen. Samples stored for extended periods should be kept at -70 degrees C.

Aged↗
PubMed1995

DNA mimics a self-protein that may be a target for some anti-DNA antibodies in systemic lupus erythematosus.

Recent studies suggest that some anti-DNA Abs in systemic lupus erythematosus may actually be Abs to specific proteins and that binding to dsDNA is a nonspecific cross-reactive event. To identify such proteins that bind to anti-DNA Abs, a cDNA expression library from human placenta was screened with mAb 3E10, a pathogenic anti-dsDNA Ab. MAb 3E10 was shown to bind to a 44-amino-acid fragment of HP8, a newly identified protein with amino acid sequence homology to the family of SPARC extracellular matrix proteins. To determine if Ab binding to both dsDNA and HP8 protein occurs through a common binding site, and therefore represents molecular mimicry, the Ab binding domains for protein and DNA were mapped. Chain recombinations between mAb 3E10 and a non-anti-DNA mAb showed that both the heavy and the light chains of mAb 3E10 were essential for anti-dsDNA and anti-HP8 reactivity. Mutagenesis experiments demonstrated that dsDNA and HP8 shared several critical binding residues located in all three complementarity-determining regions of mAb 3E10 VH. Moreover, Abs to HP8 were demonstrated in the sera of a subset of lupus patients. These results indicate that DNA mimics the HP8 protein in binding a lupus Ab, and that this protein may be a target for a subpopulation of anti-dsDNA Abs in systemic lupus erythematosus.

Animals↗
PubMed1994

Anhedonia and the intentional communication of emotion.

This study evaluated the accuracy and expressiveness of emotional communication by college students identified as anhedonic or control (ns = 24), based on their scores on the Physical Anhedonia Scale, using an emotional communication task and self-report indices of emotional expressiveness and self-monitoring. As expected, the anhedonic group reported significantly less emotional expressiveness in real-life social situations. However, contrary to the hypotheses, they did not differ from controls on measures from a laboratory communication task or on self-monitoring.

Adolescent↗
PubMed1991

A new breast screening programme--an audit of the first year.

The experience of a new breast screening unit is reported. In the first 12 months there was a 72.1% response rate with 9890 women being screened. After the initial screen 598 (5.8%) were referred to the Assessment clinic. Following repeated mammography and clinical examination 166 patients were referred for a surgical opinion; 105 (1.06% of the total screened) were considered to be possibly malignant; 61 further patients with clinical and mammographically benign disease were kept under review by a single surgeon; 101 patients had excision biopsies; 28 of 32 palpable breast lumps and 36 of 69 non-palpable lesions proved to be malignant.

Biopsy↗
PubMed1991

Caffeine ingestion during exercise to exhaustion in elite distance runners. Revision.

Caffeine is currently being used as an ergogenic aid by many athletes. The aim of this research was to determine whether a large dose of caffeine (10 mg.kg-1) taken immediately prior to the start of endurance exercise would have the desired effect of increasing endurance performance. Six males, who were not habitual caffeine users and who had performed at least two marathons, served as subjects in this experiment. They ran on a treadmill at a speed which had been calculated would elicit 75% of their VO2max for 45 minutes, after which time the speed was increased by two miles per hour till exhaustion. During the caffeine trial the athletes ran further than either the control or placebo conditions (p less than 0.05). Blood lactate values did not change across condition except for the final collection period which was significantly higher in the caffeine trial (p less than 0.05). As expected there was a significant time effect in all conditions (p less than 0.0001). Blood triglycerides after the start of the test were always higher in the caffeine condition but this was only significant at the 45 minute and end of exercise collection periods (p less than 0.05). The results suggest that endurance athletes can use caffeine just prior to exercise rather than one to three hours prior to exercise.

Adult↗
PubMed1990

Social and behavioral factors associated with high-risk sexual behavior among adolescents.

Relationships among risky sexual behaviors, other problem behaviors, and the family and peer context were examined for two samples of adolescents. Many adolescents reported behaviors (e.g., promiscuity or nonuse of condoms) which risked HIV or other sexually transmitted disease infection. Such risky behaviors were significantly intercorrelated. Consistent condom use was rare among those whose behavior otherwise entailed the greatest risk of infection. In both samples, an index of high-risk sexual behavior was significantly related to antisocial behavior, cigarette smoking, and illicit drug or alcohol use. Social context variables, including family structure, parenting practices, and friends' engagement in problem behaviors, were associated with high-risk sexual behavior. Finally, for sexually active adolescents, problem behaviors and social context variables were predictive of nonuse of condoms. Results were consistent across the two studies and regression weights held up well under cross-validation.

Adolescent↗
PubMed1989

Characterization of the gene for mp20: a Drosophila muscle protein that is not found in asynchronous oscillatory flight muscle.

A Drosophila melanogaster gene encoding a muscle specific protein was isolated by differential screening with RNA from primary cultures of myotubes. The gene encodes a 20-kD protein, muscle protein 20 (mp20), that is not detected in the asynchronous oscillatory flight muscles, but is found in most, if not all, other muscles (the synchronous muscles). The sequence of the protein, deduced from the DNA, contains two regions of 12 amino acids with significant similarity to high-affinity calcium-binding sites of other proteins. This protein is easily extracted from the contractile apparatus and thus does not seem to be a tightly bound structural component. The gene (located in polytene region 49F 9-13) is unique in the D. melanogaster genome and yields two transcripts, 1.0 and 0.9 kb long. The levels of the two transcripts are regulated differently during development, yet the coding regions of the two transcripts are identical.

Amino Acid Sequence↗
PubMed1988

Creativity and schizotypal traits. Creativity test scores and perceptual aberration, magical ideation, and impulsive nonconformity.

Using a nonclinical and noneminent population, this study demonstrates an overlap in creative and schizotypal traits in the areas of perceptual functioning, behavioral and personality styles, and interests. No such overlap is observed in the area of divergent thinking. A battery containing five creativity measures was administered to a group of college student subjects scoring high on either the Perceptual Aberration Scale or the Magical Ideation Scale (N = 52) and to a group of control subjects (N = 65). A multivariate analysis of variance indicated that subjects high on the schizotypal traits of Perceptual Aberration or Magical Ideation (Per-Mag subjects) differed significantly from control subjects on the five creativity tests. Per-Mag subjects scored significantly higher than control subjects on the Barron-Welsh Revised Art Scale, a measure of preferences for figures, and the How Do You Think, a biographical and personality measure. There was a tendency for female Per-Mag subjects to score higher than female control subjects on the Domino Creativity Scale of the Adjective Check List. Per-Mag and control subjects did not differ on the Gough Creative Personality Scale of the Adjective Check List or on the Alternate Uses test, a test of divergent thinking. Per-Mag subjects who scored above the median for their group and gender on the Impulsive Nonconformity Scale received the highest creativity scores on the Barron-Welsh Revised Art Scale and the How Do You Think, although these results only approached significance. These findings argue for the specificity of areas of similarity and difference in schizotypy and creativity.

Adult↗
PubMed1984

Target antigens in malaria transmission blocking immunity.

Malaria transmission blocking immunity has been found to operate against two distinct phases of development of malaria parasites in the mosquito midgut: (i) against the extracellular gametes and newly fertilized zygotes shortly after ingestion by a mosquito of parasitized blood and (ii) against the zygotes during their subsequent development into ookinetes. Immunity is antibody-mediated and stage-specific. A set of three proteins, synthesized in the gametocytes, expressed on the surface of the gametes and newly fertilized zygotes and subsequently shed during later transformation of the zygotes, has been identified as the target antigens of anti-gamete fertilization blocking antibodies. A single protein, synthesized and expressed on the zygote surface during its development to ookinetes, has been identified as the target of antibodies which block the development of the fertilized parasites in the mosquito. Immunization of human populations against gamete or zygote antigens, while not directly protecting an immunized individual from inflection, would reduce the transfer of malaria within the population. Such immunity, in addition to reducing the overall rate of malaria transmission, would, if combined with a vaccine against the asexual (disease-causing) stages, reduce the chance of selection of parasites that are resistant to the asexual vaccine by preventing their entry into the mosquito population.

Animals↗
PubMed1983

Telomere regions in Drosophila share complex DNA sequences with pericentric heterochromatin.

A 12 kb fragment of Drosophila melanogaster DNA cloned in a lambda phage, lambda T-A, is shown by in situ hybridization to contain sequences homologous to DNA at the extreme ends of each of the polytene chromosomes and to the pericentric sequences present in the beta heterochromatin. This pattern of hybridization is seen for each of the four D. melanogaster stocks that have been studied. Most of the sequence in lambda T-A shows no detectable homology to DNA within the banded chromosome arms. (The only exception is what appears to be a short mobile element inserted in lambda T-A. This portion of lambda T-A hybridizes with internal arm sites that vary from stock to stock). Analysis of restriction fragments of genomic DNA indicates that the sequences in lambda T-A are homologous to complex sets of repeated sequences that differ from stock to stock in D. melanogaster. Some, but not all, of the members of these sets are underreplicated during polytenization in D. melanogaster. The sequences in lambda T-A are also homologous to complex sets of repeated sequences in the genomes of other Drosophila species belonging to the melanogaster species group. Pericentric and telomeric localization is conserved in these related species, although analysis of DNA fragments shows marked changes in sequence organization on a finer scale. The constancy of the localization of lambda T-A-homologous sequences to telomeric and pericentric regions suggests that these sequences serve a function in those regions.

Animals↗
PubMed1982

Benzodiazepine hypnotics remain effective for 24 weeks.

Ninety-seven poor sleepers aged 40-68 years took capsules nightly for 32 weeks and made daily subjective ratings. The benzodiazepine hypnotics lormetazepam 2 mg and nitrazepam 5 mg appeared still to improve sleep after 24 weeks of intake when compared with continuous placebo intake. The sustained effectiveness was most evident in a significant shortening of the time taken to fall asleep in patients receiving lormetazepam. After weeks, sleep latency and the quality of sleep were significantly worse than baseline values. The impairment was maximal on the second night after withdrawal of lormetazepam and on the fourth night after withdrawal of nitrazepam. It is concluded that benzodiazepines remain effective for at least 24 weeks but that a period of disturbed sleep may be expected after withdrawal.

Adult↗