Biomedical subjects

S Binkley

Publications and source records attributed to S Binkley.

At least 19 recordsLinked to original sources

PubMed1996

Field observations of yawning and activity in humans.

Rates of wrist activity and yawning were recorded continuously for 7-15 days in adult human male and female subjects. In the 15 min following 747 yawns wrist motion increased reliably in all subject records. The data were consistent with an hypothesis that yawning is predictive of an increase in activity level. In a second study, data from daily logs kept by 45 subjects confirmed previous findings that yawning frequency is unrelated to prior amount of sleep, or to times of awaking or retiring. More yawning occurred during the week than during weekends.

Adolescent↗

PubMed1994

Wrist motion rhythm phase shifts in travelers may differ from changes in time zones.

Wrist motions (223-471)/5 min were measured during 17-32 days of continuous recordings made from human passengers as they traveled across zero to five time zones for business and pleasure. The travelers all exhibited daily cycles of activity and rest. The duration of daily activity, alpha, was 1.1 h less at the destination; the mean was 63 wrist motions/5 min less at the destination. Phase shifts of the daily rhythm (e.g., acrophases, 0.0 to 5.3 h) advanced or delayed in the direction expected from time zone changes. However, the magnitude of the phase shifts differed (e.g., as much as 2.3 h) from the expected changes because of transmeridian travel and there were phase shifts even when there was no change in time zone. Differences were observed in phase shifts assessed by different methodologies of determining phase (waveforms, onsets, offsets, acrophases).

Adult↗

PubMed1993

Structures and molecules involved in generation and regulation of biological rhythms in vertebrates and invertebrates.

Melatonin from the retina and the pineal gland functions in neuroendocrine hierarchies. Photoreceptors--eyes and extraretinal--detect light. Oscillators--pineal and suprachiasmatic nuclei--act as pacemakers. Driven neuroendocrine rhythms carry temporal hormone signals throughout the body. Light controls melatonin: light sets the phase of the melatonin rhythm and determines the duration of melatonin synthesis. By these means, circadian rhythms (e.g., in locomotor activity and body temperature) and seasonal rhythms (e.g., in reproduction) are controlled.

Animals↗

PubMed1993

98.6 degrees.

Explore the source record for details and available documents.

Body Temperature↗

PubMed1993

Individual, phase, and weekly variations in daily cycles of wrist activity in freeliving humans.

Wrist activity was monitored in 17 college students for 11-15 days each. Records of individuals had distinctive patterns, like fingerprints. The subjects all exhibited daily cycles in their activity with activity during the daytime and with period lengths close to 24 h. There was individual variation in average phase (onset 5.3 h, offset 4.5 h, acrophase 6.1 h). Individual subjects all showed 7-day oscillations in their activity patterns associated with the weekly work-leisure schedules. During the leisure weekends, the subjects as a group had a 2.1-h delay in onset, a 1.5-h delay in acrophase, and a 0.8-h shortening in alpha.

Adult↗

PubMed1992

Wrist activity in a woman: daily, weekly, menstrual, lunar, annual cycles?

Wrist activity was monitored continuously for one year in a woman who went about her normal life. The year of data were analyzed for changes and rhythms--daily, weekly, menstrual, lunar, annual. For each day, average motions/5 minutes, activity onset, activity offset, alpha (duration of activity), and acrophase were measured. Periodograms and average daily wave forms were calculated. Well-defined, entrained, daily rest-activity cycles were observed throughout the year with periods close to 24 hours. There was weekend delay (0.7 hours) in onset, weekend decrease in alpha (1.0 hours), and weekend advance of acrophase (0.4 hours). Motions/5 minutes decreased 9%, onsets were 0.3 hours later, and alphas were 0.4 hours shorter on menstrual cycle days 8 through 18 which should have encompassed the time of ovulation. Lunar phase had no effect. Annual changes in onset (1.1 hours), offset (1.2 hours), and acrophase (1.1 hours) were attributed to the 1-hour change between standard and daylight savings time.

Circadian Rhythm↗

PubMed1990

Human daily rhythms measured for one year.

Four human subjects recorded their wake-up and to-sleep times for one year each. The data were plotted to display individual circadian rhythms and the data were analyzed statistically. First, individuals had characteristic patterns in which visible changes in the patterns were observed mainly when time zones were changed because of travel. Second, the months with the latest wake-up and latest to-sleep times concentrated around the winter solstice; the months with the earliest wake-up and earliest to-sleep times concentrated around the fall equinox. Third, new moon versus full moon days were not different. Fourth, one-hour changes between standard and daylight savings time in the USA were reflected by near one-hour changes in two subjects, but not in a third. Fifth, weekend delays in wake-up time (0.8-1.6 hours), weekend delays in to-sleep time (0.1-0.5 hours), and shorter weekend awake time (0.8-1.3 hours) were observed. Sixth, throughout the year, wake-up times were close to the time of sunrise, but to-sleep times were several hours past sunset.

Adult↗

PubMed1990

Day-night differences in the vesicle populations of nerve terminals in the rat and chick pineal gland.

Day-night differences in the ultrastructure of pineal neuronal elements were quantitated in the rat and the chick--two species that exhibit important differences in adrenergic control of melatonin synthesis. Area densities of small clear vesicles (40-60 nm) and small dense-cored vesicles (40-60 nm) in nerve terminals were significantly reduced during the night in the rat. In the chick, there were no day-night differences in the frequency of clear vesicles, but the number of small dense-cored vesicles tended to be greater at night. There was no effect of day-night sampling on area densities of large dense-cored vesicles (80-120 nm) in either species. These findings are consistent with biochemical evidence for day-night species differences in the adrenergic control of pineal function.

Animals↗

PubMed1989

Photoperiod modifies daily maps of light and dark sensitivity for N-acetyltransferase activity in pineal glands of 3-week old Gallus domesticus.

N-acetyltransferase (NAT) activity in pineal glands exhibits a circadian rhythm with peak activity occurring in the dark-time. We previously showed that in Gallus domesticus chicks pretreated with LD12:12, NAT activity was increased by dark exposure (peak dark sensitivity occurred during the expected dark-time) or decreased by light at night (peak light sensitivity occurred early in the night during the time of dark sensitivity). In this study we mapped dark sensitivity vs time (for NAT activity increase in response to 2 h dark pulses), and light sensitivity vs time (for NAT activity decrease in response to 10 min or 30 min light pulses) over a cycle for 3-week old chicks, Gallus domesticus, pretreated with long (LD16:8) or short photoperiod (LD8:16). Sensitivity to light was increased in the second 8 h after L/D by LD8:16. Sensitivity to dark was increased in the first 8 h after L/D by LD16:8.

Acetyltransferases↗

PubMed1989

Weekly phase shifts of rhythms self-reported by almost feral human students in the USA and Spain.

Eleven students in the USA and fifteen students in Spain wrote their wake-up and to-sleep times on forms for a month. The subjects reported large day-to-day phase shifts of magnitude comparable to those of travelers and shiftworkers. All individuals exhibited some large phase shifts of their day-to-day wake-up and to-sleep times (largest shift average, 4.54 hours; range, -12.7 to +13.9 hours). The students had daily cycles and weekly cycles in their wake-up and to-sleep times. Synchrony (entrainment) with the 24-hour environment was achieved by large weekly phase advances (individual averages ranged 1.2-4.8 hours) rather than by small daily adjustments. There was considerable variation in awake time: there were 2-3 hour differences between individuals, and there were 3.2 hour differences depending on day of the week. Alarm use appeared to be the Zeitgeber, in contrast to laboratory studies which show light and social Zeitgebers for humans. There was a 4 hour difference between the Spanish and USA students which was attributed to the 5 hour difference in time zones. Wake-up time and prior to-sleep time were interdependent.

Adult↗

PubMed1989

Advancing schedules and constant light produce faster resynchronization of circadian rhythms.

House sparrows, Passer domesticus, were subjected to rotated light-dark (LD) cycles that consisted of repeated 8-hr advances or delays of 5 days of LD 8:16, with intervening 40-80 hr of constant dark or light. Sparrows reset the fastest (by the second cycle) when they were advanced with intervening constant light (LL). They reset the slowest (taking six cycles) when they were delayed with intervening constant dark (DD).

Animals↗

PubMed1988

Xenopus tadpole melanophores are controlled by dark and light and melatonin without influence of time of day.

Melanophores were studied in tadpoles of the South African clawed toad, Xenopus laevis, during the first week after hatching (stages 46-49) at 25 degrees C. The tadpoles had melanophores with dispersed melanosomes in the light and punctate melanophores in the dark in LD 12:12. The melanophores remained punctate in constant dark and the melanosomes remained dispersed in constant light. Lights-out (in the light-time of LD 12:12) caused the melanophores to become punctate, which occurred more quickly than the dispersion of melanosomes, which commenced when the lights were turned on (in the dark-time of LD 12:12). Melanophores with dispersed melanosomes in tadpoles (in constant light) became punctate in response to a series of melatonin concentrations (0.2-5 ng/ml) in their bathing water irrespective of the time of day melatonin was administered. An image-analysis technique for assessing melanophore responses was tested.

Animals↗

PubMed1987

Sparrow circadian rhythm responses to rotated light-dark schedules.

House sparrows, Passer domesticus, were individually subjected to light-dark regimens while their perching activity was continuously monitored. The sparrows resynchronized in 5 days when LD8:16 (8 hr of light alternating with 16 hr of dark) was advanced by 8 hr; however, the sparrows were 1.7 hr from resynchronization after 5 days when the schedule was delayed 8 hr. Sparrows subjected to two simultaneously presented light-dark schedules (rotated LD8:16 provided by one light source imposed together with LD12:12 provided by a second light source) did not ignore either cycle; instead the sparrows responded as to a sequence of photoperiods; they resynchronized the onsets of their activity with the first time of lights-on of the collective photoperiod provided by the two light sources.

Animals↗

PubMed1987

Circadian rhythm in pineal N-acetyltransferase activity: rapid phase reversal and response to shorter than 24-hour cycles (IV).

N-Acetyltransferase (NAT) is an enzyme whose rhythmic activity in the pineal gland and retina is responsible for circadian rhythms in melatonin. The NAT activity rhythm has circadian properties such as persistence in constant conditions and precise control by light and dark. Experiments are reported in which chicks (Gallus domesticus), raised for 3 weeks in 12 h of light alternating with 12 h of dark (LD12:12), were exposed to 1-3 days of light-dark treatments during which NAT activity was measured in their pineal glands. (a) In LD12:12, NAT activity rose from less than 4.5 nmol/pineal gland/h during the light-time to 25-50 nmol/pineal gland/h in the dark-time. Constant light (LL) attenuated the amplitude of the NAT activity rhythm to 26-45% of the NAT activity cycle in LD12:12 during the first 24 h. (b) The timing of the increase in NAT activity was reset by the first full LD12:12 cycle following a 12-h phase shift of the LD12:12 cycle (a procedure that reversed the times of light and dark by imposition of either 24 h of light or dark). This result satisfies one of the criteria for NAT to be considered part of a circadian driving oscillator. (c) In less than 24-h cycles [2 h of light in alternation with 2 h of dark (LD2:2), 4 h of light in alternation with 4 h of dark (LD4:4), and 6 h of light in alternation with 6 h of dark (LD6:6)], NAT activity rose in the dark during the chicks' previously scheduled dark-time but not the previously scheduled light-time of LD12:12. In a cycle where 8 h of light alternated with 8 h of dark (LD8:8), NAT activity rose in both 8-h dark periods, even though the second one fell in the light-time of the prior LD12:12 schedule.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetyltransferases↗

PubMed1987

Diurnal variation of cation pump enzyme activity in pineal and seven other rat brain regions.

Adult female Long-Evans rats were maintained on an automatically regulated artificial lighting schedule of light:dark (L:D) 14.5:9.5 for 12 wk. After sacrifice at 0630, 1130, 1600, 1800, 2000, 2200, 0230, or 0400, the pineals were removed, weighed, and assayed for N-acetyltransferase (NAT), melatonin, Mg++-paranitrophenylphosphatase (pNPPase), and K-pNPPase activity. The brains were quickly dissected into the following areas: cerebellum, superior colliculi, inferior colliculi, visual cortex, auditory cortex, sensorimotor cortex, and the hypothalamic area around the suprachiasmatic nucleus. These regions were weighed and 10% sucrose homogenates were prepared for determinations of protein, Mg++-pNPPase, and K+-pNPPase activity. Pineal melatonin rose over six-fold from 144 +/- 70 pg/gland at 1130 to 981 +/- 173 pg/gland at 0230. Similarly, pineal NAT activity rose over 11-fold, from 119 +/- 12 pmol/gland/h to 1315 +/- 232 pmol/gland/h at the same times. K+-pNPPase activity rose by about two-thirds, from 133 +/- 12.8 nmol/gland/h to 224 +/- 22.3 nmol/gland/h from 1600 to 0230. However, when expressed per mg protein, these differences in pNPPase activity were not significant. There were no significant daily rhythms discernible in any of the seven other brain regions across these times. We conclude that cation pump enzyme activity varies only slightly with time in the rat brain and pineal gland, in spite of definite daily rhythms of pineal melatonin and NAT activity.

4-Nitrophenylphosphatase↗

PubMed1987

Circadian rhythm resetting in sparrows: early response to doublet light pulses.

Circadian responses were studied using the perching activity of house sparrows (Passer domesticus). The sparrows were subjected to single or double 4-hr light pulses (the single pulses or the second pulses of the doublets scanned 24 hr) in the first cycle after previous entrainment to a light-dark cycle (LD 12:12). The differences in times at which the birds commenced perch-hopping in LD 12:12 before the pulses and in the five cycles immediately following the pulses were determined (phase shifts). A 24-hr time profile for phase shifts in response to single light pulses replicated our previous study: Early-night pulses delayed the rhythm (-1.7 hr), while late-night pulses advanced the rhythm (+3.8 hr). After pretreatment with a light pulse that advanced the birds +2.7 hr, the resetting curve was advanced. There were no delays; the range of average shifts was +0.1 hr to +6.2 hr. After pretreatment with a light pulse that delayed the birds -1.7 hr, the resetting curve was delayed. Average delays as much as -1.1 hr and advances up to +2.1 hr were measured. The data for double pulses were interpreted from predictions made from single-pulse data.

Animals↗

PubMed1986

Photoperiod modifies circadian resetting responses in sparrows.

Circadian responses to photoperiod were studied in house sparrows (Passer domesticus) by subjecting them to 4-h light pulses and measuring the subsequent phases of their circadian rhythms. The direction and magnitude of phase shifts in response to 4-h light pulses following pretreatment with light-dark cycles (LD) 16:8 or LD 8:16 varied with time of day; advances (3.4 h) occurred when pulses were imposed in the late subjective night on both groups of birds; delays (-2.1 h) occurred when the pulses were imposed in the early subjective night on the LD 8:16 birds. The time profiles for responses to light pulses that scanned 24 h (phase-response curves) were modified by long and short photoperiod. Short photoperiod 1) increased amplitude (1.7 h), 2) increased time from the prior lights-out to the peak of advances (6 h), and 3) decreased the mean phase shift (0.9 h).

Animals↗

PubMed1985

Direct and circadian control of sparrow behavior by light and dark.

House sparrows, Passer domesticus, have perch-hopping activity (1) which was elicited by light (direct), and (2) which exhibited daily rhythms that were entrained by environmental light-dark cycles (circadian). When photoperiod was more than 14 hr, the sparrows' activity coincided with the light; when it was less than 14 hr, the birds were also active in the dark according to circadian predictions. Bimodality was dependent on photoperiod with the maximum incidence (75%) in LD16:8. Sparrows placed in LD1:11 (skeleton of 13:11) synchronized the onsets of their activity with the light beginning 8-18 hr after the time of the last L/D irrespective of when the birds experienced the first 1 hr light. Thirty-five percent of the sparrows advanced when they entrained to LD1:11 with the first pulse 8 hr after the last L/D; 76-87% of the sparrows delayed when they entrained to LD1:11 with the first pulse 2, 5 or 18 after the last L/D. Sparrows kept in exotic light-dark cycles (with periods of 10 min, 1.5 hr, 3.0 hr, 6.0 hr, 12 hr) were active in the light. Some birds displayed circadian rhythms superimposed on short period patterns. The period lengths of the circadian rhythms were shorter (22.8 hr) than in constant dark (24.2 hr). When sparrows subjected to LD1.5:1.5 or 36 hr of constant light were placed in constant dark, the phase of their activity onsets extrapolated to 15 hr after the last lights-off.

Animals↗