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Biomedical subjects

J I Amberson

Publications and source records attributed to J I Amberson.

7 recordsLinked to original sources
PubMed1991

Psychophysiological parameters of migraine and muscle-contraction headaches.

Previous headache studies have been unable to verify the presumed presence of headache. Attempting to correct this design fault, the present study assessed four psychophysiological measures (frontalis EMG, temporal BVP, temporal and finger skin temperature) and salient subjective measures in 13 migraineurs, eight muscle-contraction headache sufferers, and 13 age-matched normals. All subjects submitted to two 30-minute sessions of quiet monitoring, and for the headache subjects, one of the sessions was headache active. A bogus, but convincing preliminary "assessment" revealed insufficient headache activity in the headache active session, forcing subjects to reschedule that session in the future when a strong headache was present. A parallel manipulation was employed with the normal subjects. A MANOVA failed to discriminate within- or between-group differences on the psychophysiological measures. Self-reported pain was uncorrelated with the psychophysiological indices. These results cast further doubt on the validity of the psychophysiological measures employed in this study, the same ones routinely endorsed by headache researchers and therapists. We discuss problems of recruitment, compliance, and attrition in basic headache research.

Electromyography↗
PubMed1985

Hemodynamics of sequential orgasm.

Seventeen women masturbated to orgasm several times in succession while being measured intravaginally by a device that allows continuous oxygen and blood flow readings. Analysis of covariance showed significant differences between fantasy and orgasm and between orgasm and interorgasm relaxation periods. The data do not provide physiological evidence that successive orgasms are either physiologically or subjectively stronger but do provide physiological evidence of a plateau phase of sexual response in women.

Adult↗
PubMed1982

Intravaginal prostaglandin E1 increases vaginal blood flow.

We investigated the possibility that PGE1, at approximately the minimal seminal plasma concentration reported to be associated with human fertility (3), placed in the vaginas of female dogs might produce local vasodilation and thereby increase vaginal blood flow. Fifteen micrograms of PGE1 in 1 ml, 38 degrees C saline increased vaginal blood flow 2.5 times (0.27 +/- 0.10 to 0.67 +/- 0.10 ml/g X min) as compared to control (1 ml, 38 degrees C saline, intravaginally) without altering arterial pressure, hepatic blood flow, or renal blood flow. We conclude that seminal fluid PGE1 can produce vaginal vasodilation. The role of seminal fluid PG induced increases in vaginal blood flow upon reproductive success, if any, is entirely speculative.

Animals↗
PubMed1982

Prostaglandin E1 increases blood flow to the cervix uteri.

PGE1 occurs in high concentration in seminal fluid and is apparently necessary for normal fertility, although its specific function(s) is not known. We investigated the possibility that PGE1, at seminal fluid concentration, could increase cervical blood flow and, thus, potentially alter cervical mucus properties, including O2 concentration. Fifteen micrograms PGE1/ml placed directly on the cervix uteri increased cervical blood flow in anesthetized dogs from 0.8 +/- 0.7 to 5.7 +/- 5.1 ml/g.min 5 min following application without affecting arterial pressure or hepatic or renal blood flow. Seminal PGE1 may have effects upon oxygen tension in the cervical mucus, as well as aiding leukocyte accumulation in the cervical canal, by increasing cervical blood flow.

Alprostadil↗
PubMed1979

Age differences in dark-interval threshold across the life-span.

The threshold for the dark interval between two flashes was used to examine differences in stimulus persistence in 72 subjects aged 20 to 79 years. The data were then combined with results from two previous studies involving children and adolescents; thus, a cross sectional, adult, life-span view of differences in the dark-interval threshold was presented. Results showed that during childhood and adolescence there is a decline in stimulus persistence as a result of decreased receptor sensitivity. In adulthood, however, the dark-interval threshold remains fairly stable until the 70s where it increases significantly. Two possible explanations for this increase in stimulus persistence in old age are discussed.

Adult↗