scholarly journals Low-frequency arterial pressure fluctuations do not reflect sympathetic outflow: gender and age differences

1998 ◽  
Vol 274 (4) ◽  
pp. H1194-H1201 ◽  
Author(s):  
J. Andrew Taylor ◽  
Todd D. Williams ◽  
Douglas R. Seals ◽  
Kevin P. Davy
Keyword(s):  
Arterial Pressure ◽  
Low Frequency ◽  
Total Activity ◽  
Sympathetic Outflow ◽  
Pressure Oscillations ◽  
Young Males ◽  
Young Females ◽  
Sympathetic Nervous ◽  
Mayer Wave ◽  
Older Males

Low-frequency arterial pressure oscillations (Mayer waves) have been proposed as an index of vascular sympathetic outflow. However, cross-sectional differences in these pressure oscillations may not reflect different levels of sympathetic nervous outflow in humans. Three groups of healthy subjects with characteristically different sympathetic nervous outflow were studied: young females ( n = 10, 18–28 yr), young males ( n = 11, 18–29 yr), and older males ( n = 13, 60–72 yr). Average R-R interval, arterial pressures, and systolic pressure variability at the Mayer wave frequency (0.05–0.15 Hz) did not differ among the three groups. Diastolic pressure Mayer wave variability was similar in young females vs. young males (39 ± 10 vs. 34 ± 5 mmHg2) and lower in older males vs. young males (14 ± 2 mmHg2; P < 0.05). In contrast, muscle sympathetic activity was lowest in young females (892 ± 249 total activity/min) and highest in older males (3,616 ± 528 total activity/min; both P < 0.05 vs. young males: 2,505 ± 285 total activity/min). Across the three groups, arterial pressure Mayer wave variability did not correlate with any index of sympathetic activity. Our results demonstrate that arterial pressure Mayer wave amplitude is not a surrogate measure of vascular sympathetic outflow.

Male white grub beetles prefer the pheromone composition of young females in the field

2016 ◽  
Vol 106 (5) ◽  
pp. 679-684 ◽  
Author(s):  
N. Fujiwara-Tsujii ◽  
H. Yasui ◽  
S. Wakamura ◽  
A. Nagayama ◽  
N. Arakaki
Keyword(s):  
Sex Pheromones ◽  
Flight Tunnel ◽  
White Grub ◽  
Young Males ◽  
Young Females ◽  
Dasylepida Ishigakiensis ◽  
Female Pheromone ◽  
Pheromone Composition ◽  
Older Males ◽  
Qualitative Changes

AbstractFemales of the white grub beetle, Dasylepida ishigakiensis, release both (R)- and (S)-2-butanol as sex pheromones, but the males are only attracted to (R)-2-butanol. In laboratory-reared females, the proportion of the (R)-isomer decreased significantly as their calling opportunities increased and as they aged. We examined whether such qualitative changes also occur in field populations. We collected virgin females from the field and then trapped and analysed the volatiles emitted during their first and second callings. The ratio of (R)- to (S)-2-butanol (R/S) was 78:22 at the first calling, but shifted to 39:61 at the second calling. While investigating the composition of the female pheromones, the question arose as to whether the male preferences change in response to the shift in female pheromone composition. To answer this question, we observed the behaviour of young and old males in response to various R/S ratios as lures in the laboratory and in the field. In the flight tunnel assay of laboratory-reared individuals, young males touched female models with a 9:1 R/S ratio lure less than those with pure (R)-2-butanol; however, older males touched the two groups with equivalent frequency. In the field trap test, older males were much more attracted to (R)-2-butanol-scented lures. When we tested using lures with the same amount of (R)-2-butanol but added different amounts of the (S)-isomer, we found that increased levels of (S)-2-butanol resulted in lower attractiveness to males. (S)-2-butanol was confirmed to have an inhibitive activity in the attractiveness of (R)-2-butanol.

Effect of area postrema lesion on low-frequency arterial pressure oscillations in dogs

1987 ◽  
Vol 253 (3) ◽  
pp. H524-H530 ◽  
Author(s):  
F. E. Pollick ◽  
K. L. Barnes ◽  
C. M. Ferrario
Keyword(s):  
Arterial Pressure ◽  
Area Postrema ◽  
Control Period ◽  
Power Spectra ◽  
Low Frequency ◽  
Experimental Period ◽  
Low Frequency Oscillation ◽  
Pressure Oscillations ◽  
Before And After ◽  
Group A

To explore the possibility that chronic inactivation of the area postrema (AP) may alter the frequency distribution of oscillations in blood pressure, the power spectra for mean arterial pressure (MAP) were evaluated in conscious dogs before and after heat coagulation (n = 4) or sham lesions (n = 6) of the AP. No significant changes in MAP were observed in either group of dogs after surgery. Tachycardia was seen in AP-lesioned animals after surgery; no consistent changes in heart rate were found in sham-lesioned dogs. Spectra were averaged to provide a group spectral estimate for the AP-lesioned and sham-lesioned groups, respectively, for each experimental period. In the sham-lesioned group a variance peak was observed at approximately 0.03 Hz both before and after surgery. The same peak was seen in the AP-lesioned group during the control period but disappeared following AP lesion, apparently because a greater proportion of the variance was shifted toward frequencies below 0.03 Hz. In addition, a peak related to respiratory rate was present in both groups before surgery but was selectively abolished by AP lesion. AP lesion also substantially reduced the power associated with frequencies between 0.1 and 0.4 Hz. The use of spectral analysis has allowed us to demonstrate that a low-frequency oscillation of MAP in conscious, resting dogs requires the integrity of the AP and that the 0.1- to 0.4-Hz components of the variability of MAP are attenuated after removal of the AP.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood pressure oscillations impact signal-averaged sympathetic transduction of blood pressure: implications for the association with resting sympathetic outflow

2021 ◽  
Vol 321 (4) ◽  
pp. H798-H806
Author(s):  
Massimo Nardone ◽  
Carlin Katerberg ◽  
Anthony V. Incognito ◽  
André L. Teixeira ◽  
Lauro C. Vianna ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Pressure ◽  
Sympathetic Nerve Activity ◽  
Muscle Sympathetic Nerve Activity ◽  
Operating Pressure ◽  
Sympathetic Outflow ◽  
Current Signal ◽  
Signal Averaging ◽  
Nerve Activity ◽  
Pressure Oscillations

The current signal-averaging technique for calculating sympathetic transduction of blood pressure does not consider the arterial pressure at which each muscle sympathetic burst occurs. A burst firing when mean arterial pressure is above the operating pressure was associated with a decrease in blood pressure. Thus, individuals with higher muscle sympathetic nerve activity demonstrate a reduced sympathetic transduction owing to the weighted contribution of more sympathetic bursts at higher levels of arterial pressure.

scholarly journals Effects of aging, hypertension, and diabetes on low‐frequency arterial pressure oscillations

2009 ◽  
Vol 23 (S1) ◽  
Author(s):  
Antti M Kiviniemi ◽  
Mikko P Tulppo ◽  
Tapio Seppänen ◽  
Katelyn Norton ◽  
Maria F Frances ◽  
...  
Keyword(s):  
Arterial Pressure ◽  
Low Frequency ◽  
Pressure Oscillations ◽  
Effects Of Aging

Impact of age and gender on frequency of interruption in dyadic interviews

2020 ◽  
Vol 21 (2) ◽  
pp. 187-199
Author(s):  
Mohammad Almoaily
Keyword(s):  
Young Female ◽  
Female Students ◽  
Age And Gender ◽  
Male And Female ◽  
Young Males ◽  
Young Females ◽  
And Gender ◽  
Older Males

Abstract This paper investigates whether the gender and/or age of interviewees in dyadic interviews influences frequency of speech interruption of young female interviewers. Forty female students at King Faisal University (KFU) and forty interviewees participated in the study. The author compared the number of interruptions per ten minutes of conversation made by interviewees belonging to four categories: young females, young males, older females, and older males. The author hypothesized that older male interviewees interrupt young female interviewers more than younger male and female interviewees. Additionally, the author hypothesized that older female interviewees interrupt young female interviewers more than young female interviewees. The results did not support the hypothesis that males interrupt females more often. Female participants made significantly more interruptions than male participants. The data do not support the hypothesis that older interviewees interrupt their interviewers more frequently than younger interviewees.

Intention to Return and Perception of the Health Risk Due to Radiation Exposure Among Residents in Tomioka Town, Fukushima Prefecture, Stratified by Gender and Generation

2020 ◽  
pp. 1-8
Author(s):  
Hitomi Matsunaga ◽  
Makiko Orita ◽  
Yasuyuki Taira ◽  
Takashi Kudo ◽  
Hisayoshi Kondo ◽  
...  
Keyword(s):  
Radiation Exposure ◽  
Health Effects ◽  
Tap Water ◽  
Young Males ◽  
Young Females ◽  
Fukushima Prefecture ◽  
Adverse Health Effects ◽  
Nuclear Disaster ◽  
Effects Of Radiation ◽  
Older Males

ABSTRACT Objective: The aim of this study was to clarify residents’ intentions to return (ITR) to Tomioka town, Fukushima Prefecture; and their risk perception of the health effects of radiation exposure as stratified by gender and generation. Methods: Of almost 8000 residents who were 20 years of age or older and who had lived, prior to the accident, in the zones of Tomioka town where residents were permitted to return, 1860 were included in the analysis. For the analysis, the residents were divided into 4 groups which were stratified by gender and age: older males (over 50 years), young males (20−49 years), older females (over 50 years), and young females (20−49 years). Results: ITR was found to be significantly lower in young males, young females, and older females than in older males. Conversely, young and older females had significantly higher levels of anxiety about drinking tap water and consuming food collected in Tomioka town. Young and older females also had greater concerns about adverse health effects on themselves and their offspring due to living in Tomioka town. Conclusion: Our results showed that special attention should be paid to younger residents, particularly to young females, with regard to recovery from a nuclear disaster.

Cerebral circulation during mild +Gz hypergravity by short-arm human centrifuge

2012 ◽  
Vol 112 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Ken-ichi Iwasaki ◽  
Yojiro Ogawa ◽  
Ken Aoki ◽  
Ryo Yanagida
Keyword(s):  
Steady State ◽  
Transfer Function ◽  
Arterial Pressure ◽  
High Frequency ◽  
Cerebral Circulation ◽  
Cerebral Autoregulation ◽  
Low Frequency ◽  
Frequency Range ◽  
Pressure Oscillations ◽  
Dynamic Cerebral Autoregulation

We examined changes in cerebral circulation in 15 healthy men during exposure to mild +Gz hypergravity (1.5 Gz, head-to-foot) using a short-arm centrifuge. Continuous arterial pressure waveform (tonometry), cerebral blood flow (CBF) velocity in the middle cerebral artery (transcranial Doppler ultrasonography), and partial pressure of end-tidal carbon dioxide (ETco2) were measured in the sitting position (1 Gz) and during 21 min of exposure to mild hypergravity (1.5 Gz). Dynamic cerebral autoregulation was assessed by spectral and transfer function analysis between beat-to-beat mean arterial pressure (MAP) and mean CBF velocity (MCBFV). Steady-state MAP did not change, but MCBFV was significantly reduced with 1.5 Gz (−7%). ETco2 was also reduced (−12%). Variability of MAP increased significantly with 1.5 Gz in low (53%)- and high-frequency ranges (88%), but variability of MCBFV did not change in these frequency ranges, resulting in significant decreases in transfer function gain between MAP and MCBFV (gain in low-frequency range, −17%; gain in high-frequency range, −13%). In contrast, all of these indexes in the very low-frequency range were unchanged. Transfer from arterial pressure oscillations to CBF fluctuations was thus suppressed in low- and high-frequency ranges. These results suggest that steady-state global CBF was reduced, but dynamic cerebral autoregulation in low- and high-frequency ranges was improved with stabilization of CBF fluctuations despite increases in arterial pressure oscillations during mild +Gz hypergravity. We speculate that this improvement in dynamic cerebral autoregulation within these frequency ranges may have been due to compensatory effects against the reduction in steady-state global CBF.

scholarly journals Old female reed buntings (Emberiza schoeniclus) increase extra-pair paternity in their broods when mated to young males

Behaviour ◽  
2005 ◽  
Vol 142 (11-12) ◽  
pp. 1449-1463 ◽  
Author(s):  
Karen M. Bouwman ◽  
Jan Komdeur
Keyword(s):  
Mate Guarding ◽  
Male Preference ◽  
Young Males ◽  
Young Females ◽  
Extra Pair Paternity ◽  
The Social ◽  
Socially Monogamous ◽  
Behavioural Interactions ◽  
Emberiza Schoeniclus ◽  
Older Males

AbstractIn birds, females are generally assumed to determine whether extra-pair copulations occur, and thus most studies on extra-pair paternity (EPP) have focussed on female preference for male traits, whereas female traits have been largely neglected. However, the occurrence of EPP is likely to be a result of behavioural interactions (e.g., mate guarding by the social male and escaping mate guarding by the female), and may be related to individual experience, which is expected to increase with age. We investigated the effect of age on levels of EPP in reed buntings Emberiza schoeniclus, a socially monogamous passerine with extremely high levels of extra-pair young (more than 50% of offspring). In broods of older males the rate of cuckoldry declined, which is in agreement with our previous finding that older males are more successful, either through female choice or through male experience. In contrast, older females tended to increase the level of extra-pair paternity in their broods. When including the age of the partner, we found that young males, but not old males, were cuckolded more by old females than by young females. The increase in EPP with female age is not likely to be due to disassortative mating with respect to age, an increased capacity of older females to raise a brood without male help, nor a male preference for older females. With age, males nor females changed their share in parental effort. We suggest that with increase in age, females become more choosy when selecting the male that sires their offspring, or alternatively, become more experienced at circumventing paternity assurance tactics of young males.

Enhanced sympathetic outflow and decreased baroreflex sensitivity are associated with intermittent hypoxia-induced systemic hypertension in conscious rats

2006 ◽  
Vol 100 (6) ◽  
pp. 1974-1982 ◽  
Author(s):  
C. J. Lai ◽  
C. C. H. Yang ◽  
Y. Y. Hsu ◽  
Y. N. Lin ◽  
T. B. J. Kuo
Keyword(s):  
Arterial Pressure ◽  
Intermittent Hypoxia ◽  
Baroreflex Sensitivity ◽  
Low Frequency ◽  
Systemic Hypertension ◽  
Sympathetic Outflow ◽  
Autonomic Functions ◽  
Induced Hypertension ◽  
Low Frequency Power ◽  
Frequency Power

Long-term exposure to intermittent hypoxia (IH), such as that occurring in association with sleep apnea, may result in systemic hypertension; however, the time course changes in arterial pressure, autonomic functions, and baroreflex sensitivity are still unclear. We investigated the changes in cardiovascular neural regulations during the development of chronic IH-induced hypertension in rats. Sprague-Dawley rats were exposed to repetitive 1.25-min cycles (30 s of N2 + 45 s of 21% O2) of IH or room air (RA) for 6 h/day during light phase (10 AM-4 PM) for 30 days. Arterial pressure was measured daily using the telemetry system during RA breathing. The mean arterial pressure (MAP) and interpulse interval (PPI) signals were then used to assess the autonomic functions and spontaneous baroreflex sensitivity by auto- and cross-spectral analysis, respectively. Stable MAP, low-frequency power of MAP (BLF), and low-frequency power (LF)-to-high frequency power (HF) ratio of PPI (LF/HF) were significantly higher in IH-exposed rats, compared with those of RA-exposed rats. Elevation of the MAP, BLF, LF/HF, and minute ventilation started 5 days after IH exposure and lasted until the end of the 30-day observation period. Additionally, IH-exposed rats had significant lower slope of MAP-PPI linear regression (under a successively descending and ascending) and magnitude of MAP-PPI transfer function (at frequency ranges of 0.06–0.6 Hz or 0.6–2.4 Hz) after IH exposure for 17 days. However, RA-exposed rats did not exhibit these changes. The results of this study indicate that chronic IH-induced hypertension is associated with a facilitation of cardiovascular sympathetic outflow and inhibition of baroreflex sensitivity in conscious rats.

Computer Anxiety and the Older Adult: Relationships with Computer Experience, Gender, Education and Age

1992 ◽  
Vol 36 (2) ◽  
pp. 185-189 ◽  
Author(s):  
Jennifer L. Dyck ◽  
Janan Al-Awar Smither
Keyword(s):  
Older Adults ◽  
Computer Anxiety ◽  
Negative Relationship ◽  
Computer Experience ◽  
Younger Adults ◽  
Young Males ◽  
Young Females ◽  
Gender Education ◽  
Research Findings ◽  
Older Males

Research in the area of computer anxiety has traditionally concentrated on the younger adult. In this study older adults (55 years and over) were compared to younger adults (30 years and under) on levels of computer anxiety and computer experience. Subjects in the study completed a demographic and computer experience questionnaire, and two computer anxiety scales. Previous research findings indicating a negative relationship between computer anxiety and computer experience was replicated for both young and older adults. Additional findings indicated that older adults were less computer anxious and had less computer experience than younger adults. Furthermore, older subjects indicated more liking for computers than younger subjects. However, while young males liked computers more than young females, no differences between older males and older females were found on the computer liking subscale. Some discrepancies between the two computer anxiety scales suggest further research is needed to validate computer anxiety scales for use with older adults.

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