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Biomedical subjects

B Traub

Publications and source records attributed to B Traub.

11 recordsLinked to original sources
PubMed2000

Hearing threshold and frequency discrimination in the purely aquatic frog Xenopus laevis (Pipidae): measurement by means of conditioning.

Hearing threshold and frequency discrimination for underwater sound were measured in the clawed frog Xenopus laevis by means of conditioning. A go/no go discrimination procedure was used in which the test tone was presented concurrently with a wave on the surface of the water. The tone signalled whether or not the frog should respond to the wave. The hearing range of X. laevis was 200-4000 Hz. Similar thresholds of 92-96 dB re 1 microPa were found at 600 Hz, 1400-1800 Hz and 3200-3600 Hz. A high threshold at 1000-1300 Hz suggested that this was the frequency range between the sensitivities of the amphibian and basilar papillae. Relative frequency discrimination was approximately 5 % at 400-800 Hz, 45 % at 1000 Hz and 2.4-6 % at 1600-2500 Hz. This last range encompasses the dominant frequencies of the advertisement call of this species. High discrimination acuity at these frequencies may be used in distinguishing between calling males. The threshold for a one-third-octave bandpass noise centred at 600 Hz was 27.6 dB lower than that for a pure tone of 600 Hz, suggesting that sound intensity was integrated within this bandwidth, possibly by a critical-band mechanism.

Animals↗
PubMed1990

Sensory neglect in a frog: evidence for early evolution of attentional processes in vertebrates.

Mammalian-like 'sensory neglect' phenomena were elicited in Xenopus laevis by unilateral telencephalic lesion: after damage of the caudal striatum response rate to contralateral water waves was significantly lower than to ipsilateral ones. Response accuracy, however, was not affected. Within 6-8 weeks, animals recovered from neglect of unilateral stimuli; but simultaneous bilateral stimulation revealed an enduring neglect of contralateral stimuli. Latencies during acute neglect were significantly higher than after recovery. These results suggest that the neural mechanisms of selective attention might have evolved earlier than thought so far.

Animals↗
PubMed1987

Automated platelet-sizing parameters on a normal population.

The quantitation of platelets in peripheral blood is a well-recognized tool. However, other platelet parameters that recently have become available on a routine basis with the introduction of automated cell sizers may become increasingly important in evaluating the integrity of the thrombocytic function. These parameters include mean platelet volume (MPV) and platelet-crit (PCT). This study established reliable reference ranges for these platelet parameters while taking into consideration the effects of age and sex in a study population of 447 normal persons. There was an inverse, nonlinear relationship between MPV and platelet count, with no statistical difference (P greater than 0.05) seen between males and females. Platelet-crit showed no variation with respect to age or sex, however, a direct, linear relationship was suggested between PCT and platelet count. These relationships provide a better understanding of these platelet parameters and may contribute to their use as helpful diagnostic aids.

Age Factors↗
PubMed1986

Detection of herpes simplex virus and adenovirus DNA by dot blot hybridization using in vitro synthesized RNA transcripts.

A new diagnostic assay was developed to detect herpes simplex virus (HSV) and adenovirus DNA in clinical specimens using in vitro synthesized radioactively labelled RNA transcripts from virus-specific DNA fragments cloned in transcription vector pSP 64/65. RNA probes derived from HSV-I-Eco-RI-G-DNA fragment show a sensitivity of less than 3 pg of whole plasmid DNA and hybridize only with DNA of HSV I and II, but not with other viral or cellular DNA. The analysis of 15 clinical specimens showed concordance with virus isolation, except for two culture-negative samples of cerebrospinal fluid of patients with suspected HSV encephalitis, which was confirmed by serology as well as by hybridization. Using RNA transcripts from adenovirus-2-Hind-III-D-DNA fragment, we attained a sensitivity of less than 3 pg of whole plasmid DNA. This probe detected different types of adenovirus, but failed to hybridize to other viral, bacterial or cellular DNA. Compared with the cell culture method this assay did not show any false-positive or false-negative results in 16 different clinical specimens. The technique is sensitive, specific and useful for screening clinical specimens and may be helpful in confirming the diagnosis of HSV encephalitis.

Adenovirus Infections, Human↗
PubMed1986

Detection of human cytomegalovirus in urine by DNA-DNA and RNA-DNA hybridization.

A diagnostic hybridization assay for detecting human cytomegalovirus (HCMV) DNA in urine specimens was developed by using cloned viral DNA and in vitro-synthesized RNA probes. Both probes detected 3 pg of homologous DNA and hybridized with DNA of HCMV but not with other viral or human cellular DNA tested. In 95 urine specimens simultaneously tested by cell culture, the sensitivity of hybridization was at least 83%, and the specificity was at least 92%. This assay will be useful for rapid viral diagnosis with wide clinical applications such as screening of immunocompromised patients and quantitation of viral shedding in patients with primary or reactivated HCMV infection who may be receiving antiviral therapy.

Child↗
PubMed1985

Aberrant c-myc RNAs of Burkitt's lymphoma cells have longer half-lives.

BL67 and BL18 are Burkitt's lymphoma cell lines with t(8;14) translocations (the breakpoint is in the first exon and first intron, respectively) in which the mu-heavy chain switch region is fused to the c-myc gene in head to head orientation. In both cell lines only aberrant c-myc RNAs are found. BL67 cells contain two c-myc RNA species of 2.4 and 3.5 kb. The 2.4-kb RNA is initiated at several cryptic promoters in the first intron. The 3.5-kb RNA is transcribed from the immunoglobulin heavy chain anti-sense strand across the breakpoint of the translocation into the first exon of the c-myc gene and is then normally spliced using the physiological splice donor and acceptor sites of the c-myc gene. BL18 contains c-myc RNA of 2.4 kb initiated at cryptic promoters in the first intron and additional RNAs of 0.90 kb and 0.74 kb transcribed from the dual c-myc promoters on the reciprocal fragment of the translocation. The cytoplasmic turnover of these RNAs differs significantly from that of the normal c-myc message. The 3.5-kb RNA of BL67 cells and the 0.90-kb and 0.74-kb RNAs of BL18 cells, which are both hybrid molecules consisting of c-myc and immunoglobulin sequences, have a half-life of several hours in contrast to the normal c-myc message with a half-life of 15 min. The aberrant 2.4-kb c-myc RNAs of BL67 and BL18 cells are also more stable than the normal c-myc message and disappear with a half-life of 50 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Burkitt Lymphoma↗
PubMed1985

Resistance to various tetracyclines mediated by transposon Tn10 in Escherichia coli K-12.

Levels of resistance to tetracycline, chlortetracycline, demethylchlortetracycline, doxycycline, oxytetracycline, methacycline, pyrrolidinotetracycline, minocycline, and beta-chelocardin of Escherichia coli K-12 carrying transposon Tn10 or defined DNA segments of Tn10 were determined. In all cases, tetA was the only gene required for resistance. Doxycycline was the most effective inducer of tetA gene expression.

DNA Transposable Elements↗