Standard Deviation 1 Research Articles

A STUDY TO ASSESS THE EFFECTIVENESS OF MAHASIRS MUDRA TO RELIEVE HEADACHE AMONG HEALTHCARE PROFESSIONALS AT SELECTED HOSPITALS OF GANDHINAGAR

A experimental study was conducted to assess effectiveness of Mahasirs Mudra on healthcare professionals at selected hospitals of Gandhinagar. TheVisual Analog Pain Scale was usedas conceptual framework. A quantitative approach with one pretest posttest study design wasusedtoachievetheobjectivesof thestudy.Thesampleconsistedof50fromselectedhospitalsof. TheSystematic samplingtechniquewas usedtocollectthesample.In theexperimental group the mean of pretest was 4.08 with standard deviation 1.51 and post test mean was 3.6 with standard deviation1.68. Thecalculatedt value was 6.31 where as table value is 2 in 0.05 levelwhich shows highly significant. So, the Mahasirs Mudra was effective on hypertensive headache among healthcare professionals.

Rapid Titration With Intravenous Oxycodone for Severe Cancer Pain and Oral Conversion Ratio.

to assess a dose titration with intravenous oxycodone to achieve rapid pain relief of cancer pain of severe intensity. The second objective was to provide a conversion ratio with the oral route. Cancer patients admitted for severe pain were prospectively assessed. At admission (T0) previous opioid doses were recorded. Edmonton symptom assessment scale (ESAS) was collected from T0 until the conclusion of the observation. Intravenous boluses of oxycodone were given until the initial signs of significant analgesia were detected. The effective dose was multiplied for six and given as intravenous continuous infusion. When the patient was considered stabilized the intravenous daily dose was converted to oral oxycodone using an initial ratio of 1:2. Subsequently, doses of oral oxycodone were changed according to the clinical situation. Twenty-nine patients were examined. A mean effective bolus dose of oxycodone was 9.5 mg (SD 8.0) allowed to achieve a meaningful pain relief in a mean of 10.4 minutes (SD 3.3). The mean initial and the final infusion doses were 51.0 mg/day (standard deviation 40.9) and 69.7 mg/day ( standard deviation76.6), respectively. A significant change in pain intensity was observed at the different time intervals (P<0.0005). Conversion to oral route occurred after a mean of 2.7 days (standard deviation1.2) of intravenous oxycodone. The final mean conversion ratio was 1:2,12 ( standard deviation0.36). Rapid intravenous oxycodone dose titration resulted in rapid pain relief. The intravenous-oral conversion ratio of 1:2 is reliable. Further studies are necessary to confirm this preliminary observation.

The Effect of Transcutaneous Vagus Nerve Stimulation on Heart Rate Variability during Paced Breathing

PurposeTranscutaneous vagus nerve stimulation (tVNS) is an effective, non‐invasive method of electrically stimulating the vagus nerve without surgical procedures and it is FDA‐approved to treat cluster headache and migraine. One approach of tVNS is to stimulate the auricle branch of the vagus nerve (tVNSab) by sending a small electrical current through the tragus of the ear. Previous evidence indicates that heart rate (HR) is lowered, indices of heart rate variability (HRV) are increased, and muscle sympathetic nerve activity is decreased following 10‐15 min of tVNSab. However, these previous investigations did not control for respiration, which can influence autonomic activity. Thus, we tested the hypotheses that tVNSab would lower heart rate and increase indices of HRV that reflect cardiac parasympathetic activity during paced breathing (PB).MethodsSeven healthy adults (age: 20 ± 3 y; BMI:19 ± 7 kg/m2, 3 women) completed two randomized visits; bilateral tVNSab (pulse width = 200 ms; pulse frequency = 30 Hz) or a time‐control visit (SHAM) in which electrodes were secured on the tragus, but no current was applied. A 3‐lead ECG was utilized to record cardiac rhythm and HR. After baseline (PRE), tVNSab/SHAM was initiated and continued throughout data collection. Data were collected at PRE and during each intervention (STIM) during 5 min of PB. During PB, participants breathed in concert to a metronome set at 15 breaths/min. The root mean square of successive differences (RMSSD) was chosen as a marker of HRV in the time‐domain, while the frequency domain was assessed via low‐frequency (LF) and high‐frequency (HF) power. Additionally, non‐linear HRV analysis was performed using Poincare plots to calculate standard deviation 1 (SD1) and 2 (SD2). Values are reported as mean ± SD.ResultsHR was not different at PRE (tVNSab: 73 ± 15; SHAM: 73 ± 10 bpm; P = 0.92) or during STIM (tVNSab: 74 ± 14; SHAM: 75 ± 11 bpm; P = 0.87). RMSSD was not different at PRE (tVNSab: 69 ± 67; SHAM: 62 ± 46 ms; P = 0.16) or during STIM (tVNSab: 69 ± 70; SHAM: 58 ± 48 ms; P = 0.06) and it did not change in either condition (tVNSab: P = 0.87; SHAM: P = 0.59). LF was different at PRE (tVNSab: 1160 ± 654; SHAM: 1916 ± 1917 ms2; P = 0.01) but not during STIM (tVNSab: 1382 ± 719; SHAM: 1802 ± 1730 ms2; P = 0.14) and it did not change in either condition (tVNSab: P = 0.56; SHAM: P = 0.89). HF was not different at PRE (tVNSab: 784 ± 505; SHAM: 1076 ± 692 ms2; P = 0.70) or during STIM (tVNSab: 1119 ± 804; SHAM: 1015 ± 711 ms2; P = 0.89) and it did not change in either condition (tVNSab: P = 0.46; SHAM: P = 0.99). SD1 was not different at PRE (tVNSab: 48 ± 46; SHAM: 46 ± 38 ms; P = 0.97) or during STIM (tVNSab: 52 ± 49; SHAM: 41 ± 25 ms; P = 0.13) and it did not change in either condition (tVNSab: P = 0.73; SHAM: P = 0.67). SD2 was not different at PRE (tVNSab: 108 ± 69; SHAM: 92 ± 48 ms; P = 0.55) or during STIM (tVNSab: 113 ± 60; SHAM: 105 ± 59 ms; P = 0.89) and it did not change in either condition (tVNSab: P = 0.97; SHAM: P = 0.70).ConclusionsThese preliminary data show that a single intervention of tVNSab did not reduce HR or alter HRV in healthy college‐aged adults during PB. Contrary to our hypotheses, these data indicate that tVNSab does not elicit changes to cardiac autonomic activity that reflect greater cardiac parasympathetic activity in young healthy adults.

Stimulation method and individual health index study for real-time cardiovascular and autonomic nervous system reactivity analysis using PPG signal

Homeostasis in a healthy heart is maintained through the interaction of the autonomic nervous system (ANS) with the cardiovascular system (CS) in response to changes in the environment. However, the problem of the ANS and CS reactivity caused by aging and chronic disease increases the risk of fatal heart disease and negatively affects an individual's health. Therefore, we propose a method and heart rate variability (HRV) index that can continuously monitor the reactivity of ANS and CS in daily life. To analyze real-time changes in ANS and CS of a total of 22 subjects, HRV was induced by changing the posture from a sitting position to a standing position while measuring photoplethysmogram. As a result, it was confirmed that the HRV changed from 0.75 ± 0.11 s to 0.65 ± 0.10 s (P < 0.05) had a change value similar to the method used in clinical. Physiological ANS activity can be confirmed through the standard deviation 1 (SD1) and 2, and ANS activity reflected in CS can be obtained through the standard deviation of all NN intervals (SDNN) and the root mean square of successive heartbeat interval differences (RMSSD) analysis. As a result of analyzing the two values, the 5-minute average SD1/RMSSD is identified as an indicator that can confirm the function of the baroreceptors indicative of CS reactivity. In addition, we propose a real-time SDNN as an index that can check the term of the activated ANS in response to a sudden CS change.

Heart Rate Variability is Altered in College‐Aged Chronic Cannabis Users versus Non‐Users

Cannabis is an increasingly popular recreational drug among college students. Prior investigations have shown that acute cannabis use alters heart rate variability via increased sympathetic activation. However, the effects of chronic cannabis use on heart rate variability (HRV) have not been reported. PURPOSE We tested the hypothesis that HRV would be lower in chronic cannabis users (THC) compared to non-users (CON). METHODS Eleven cannabis users (age: 21±2 y, 2 females) and six controls (age: 20±2 y; 4 females) completed one study visit. Participants in the THC group self-reported using cannabis at least once per week for the past year or more. Participants in the CON reported to not use for 6 months prior to enrollment. Participants were instructed to abstain from alcohol for 24 h and cannabis for 72 h prior to the study visit. After 10 minutes of supine rest, heart rate (5-lead electrocardiogram) was continuously recorded at 1 kHz for 5 minutes of supine rest while participants breathed spontaneously. HRV was assessed using linear analysis via Fast Fourier transformation and non-linear analysis via Poincare plots. The root mean square of successive differences (RMSSD), percent of R-R intervals that differ by more than 50 ms (pRR50), and the standard deviation of R-R intervals (SDRR) were calculated to assess HRV in the time-domain. Fast Fourier transformation was used to assess HRV in the frequency domain (low-frequency (LF) and high-frequency (HF) power). Non-linear HRV analysis was performed using Poincare plots to calculate standard deviation 1 (SD1) and 2 (SD2). We used one-tailed unpaired t-tests to determine if the main outcome variables were different between groups. Values are reported as mean ± SD. RESULTS RRI was lower in THC (THC: 917±109 vs. CON: 1018±141 ms; P=0.06). RMSSD was lower in THC (THC: 57±21 vs. CON: 74±24 ms; P=0.07). There was no difference between groups for pRR50 (THC: 36±20 vs. CON: 47±21 %; P=0.12) or SDRR (THC: 68±16 vs. CON: 78±24 ms; P=0.15). LF power was not different between groups (THC: 1105±850 vs. CON: 1321±852 ms2; P=0.31), but HF power was lower in THC (THC: 1353±925 vs. CON: 2256±1195 ms2; P=0.05). SD1 was lower in THC (THC: 40±15 vs. CON: 53±17 ms; P=0.07). SD2 was not different between groups (THC: 86±19 vs. CON: 96±33 ms; P=0.23). CONCLUSION These preliminary data indicate that college-aged adults who regularly use cannabis have lower heart rate variability than their non-cannabis user counterparts. Based on linear and non-linear analyses, it appears that cannabis users have altered cardiac vagal activity at rest. However, more research is warranted to determine if cannabis use alters autonomic function and reactivity.

Abstract 817: Assessment and manipulation of DNA methylation in cancer cells using terahertz radiation

Abstract Carcinogenesis is closely associated with abnormal regulation of gene expression, among which DNA methylation in one of the key epigenetic modifications. Therefore, several studies have been directed towards the evaluation of DNA methylation. Here, we aimed to experimentally observe the specific signal of methylated DNA in various blood cancer cell lines using terahertz (THz) radiation, which is presented as a resonance in the spectrum. THz radiations are electromagnetic waves having frequencies of 0.1−10 THz, which falls between those of infrared radiation and microwaves. Molecular low-energy motions in THz region, such as collective vibrations, torsion of molecular structures, and hydrogen bonds, is correlated with biological characteristics, i.e., vibrational modes of DNA, structural modes in proteins, cell membrane vibrations, or enzyme activity. These features are usually presented as a characteristic resonance of the modes in the THz spectrum. In our study, the degree of global DNA methylation was obtained by the quantification of the resonance around 1.7 THz, and the results were in good agreement with those obtained by enzyme-linked immunosorbent assay (ELISA). Further, DNA demethylation was performed using high-power THz radiation around the resonance frequency of 1.7 THz, which lead to a 10% to 72% decrease in the degree of DNA methylation as shown in Table 1. Thus, our data shows the feasibility of using THz radiation for the assessment and manipulation of DNA methylation. This is the first study wherein the sensing and manipulation of DNA methylation could be achieved using a non-contact and non-invasive optical technique. Use of THz radiation for the assessment of DNA methylation might be helpful for its rapid processing, while THz manipulation of DNA methylation can avoid the toxicity of chemical demethylating agents. We propose that THz radiation may be useful for the diagnosis of cancer and we expect that THz demethylation might find potential application in cancer therapy. Change of methylation status of blood cancer DNA using high-power THz radiation.SamplesNo ExposureHigh-power THz exxpsoureChange (%) THzChange (%) ELISATHzELISARatio1THzELISARatio2119.621.8510.6111.661.0611.0040.5742.70211.341.388.2210.201.198.5710.0513.77315.151.4310.596.240.738.5558.8148.95417.731.4712.063.510.447.9880.2070.07511.271.437.8810.001.367.3511.274.90STDEV1.58STDEV1.24THz, the amplitude of terahertz resonance; ELISA, optical density of Enzyme linked immunosorbent assay; STDEV, standard deviation1 THz/ELISA of no exposure2 THz/ELISA of high-power THz exposure Citation Format: Hee-Jin Yang, Hwayeong Cheon, Jin Ho Paik, Joo-Hiuk Son. Assessment and manipulation of DNA methylation in cancer cells using terahertz radiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 817.

Relation of Various Parameters Used to Estimate Cardiac Vagal Activity and Validity of pNN50 in Anesthetized Humans

Objectives Analysis of heart rate variability (HRV) has been used as a measure of cardiac autonomic function. According to the pNN50 statistic, the percentage of differences between successive normal RR intervals (RRI) that exceed 50 ms, has been known to reflect cardiac vagal modulation. Relatively little is known about the validity of pNN50 during general anesthesia (GA). Therefore, we evaluated the correlation of pNN50 with other variables such as HF, RMSSD, SD1 of HRV reflecting the vagal tone, and examined the validity of pNN50 in anesthetized patients. Methods: We assessed changes in RRI, pNN50, root mean square of successive differences of RRI (RMSSD), high frequency (HF) and standard deviation 1 (SD1) of Poincaré plots after GA using sevoflurane anesthesia. We also calculated the probability distributions for the family of pNNx statistics (x: 2-50 ms). Results All HRV variables were significantly decreased during GA. HF power was not correlated with pNN50 during GA (r = 0.096, P = 0.392). Less than pNN47 was shown to have a correlation with other variables. Conclusions These data suggest that pNN50 can not reflect the level of vagal tone during GA.

Correlation between Decreased Parasympathetic Activity and Reduced Cerebrovascular Reactivity in Patients with Lacunar Infarct.

Reduced cerebrovascular reactivity (CVR) was found in patients with recent lacunar infarct. However, its mechanisms were controversial. The breath holding maneuver as a vasodilatory stimulus is clinically useful for an estimation of cerebrovasomotor reactivity in well co-operative patients. Patients with lacunar infarct have no higher cortical dysfunction and remain well co-operation. The breath holding maneuver is feasible and safe to perform in patients with lacunar infarct. Autonomic nervous system regulates systemic vascular activity. Regulation of autonomic function to cerebrovascular reactivity has been reported in the literature. We examined the correlation between autonomic functions with frequency and nonlinear heart rate variability (HRV) and cerebrovascular reactivity in patients with lacunar infarct by application of breath holding maneuver. Fifteen patients with lacunar infarct (8 women, age 65.6 ± 13.61) and 16 healthy controls (11 women, age 27.33 ± 3.85) were continuously monitored at baseline before maneuver (basal phase), during CVR induction (experimental phase) with breath holding maneuver and after maneuver (recovery phase), for arterial blood pressure (ABP), electrocardiography (EKG), mean cerebral blood flow velocity (mCBFV) of middle cerebral arteries (MCA) by transcranial doppler (TCD). The short term-one minute HRV was analyzed from EKG signals for low frequency (LF)/ high frequency (HF) ratio, nonlinear of standard deviation 1 (SD1), standard deviation 2 (SD2), cardiac Sample Entropy (SampEn) and Shannon Entropy. Significant increasing in mCBFV, LF/HF ratio, SD2/SD1, Shannon Entropy and inversely decreasing SampEn during breath holding maneuver compared with baseline were found in both groups (p<0.05). The trend of cerebrovascular reactivity is similar in both groups. However, there were differences of mCBFV, systolic blood pressure (SysBP) in the whole phases (basal, experiment and recovery) between patients and controls (p<0.05). Less scattered signals of SD1 with low value in patient group were illustrated from Poincaré (p<0.05). This indicated less degree of parasympathetic drive in the patients compared to the controls. Moreover, significant positive correlation between systolic bloods pressure and mCBFV in patients suggests impact of autonomic control and cerebral blood flow on the patho-physiological mechanism of vasodilatation, triggered by hypercapnia from breath holding maneuver in patients with lacunar infarct. Reduction of cerebrovascular reactivity in patients with lacunar infarct may relate with decreased parasympathetic activity. Further study is required to demonstrate whether these findings mean mechanisms of lacunar infarct or the effect of hypertensive response.

Monty Roberts' Public Demonstrations: Preliminary Report on the Heart Rate and Heart Rate Variability of Horses Undergoing Training during Live Audience Events.

Simple SummaryMonty Roberts is a famous horse trainer, commonly referred to as a ‘horse whisperer’, who shares his training methods all over the world, including through large public audience events. These events have the potential to compromise the horse’s welfare since the horses have usually been transported to the event on the day and stabled in an unfamiliar environment before being used in demonstrations watched by hundreds of people. This paper describes the opportunistic collection and analysis of heart rate (HR; beat-to-beat intervals) and heart rate variability (HRV) of horses being trained during Monty Roberts’ public demonstrations within the United Kingdom. HR and HRV measured during the demonstrations were lower (indicative of an increase in heart rate as measured in beats-per-minute) than recordings within the stable and consistent with low-moderate exercise intensities used during training. The HR and HRV during a specific training method known as “Join-up®” were comparable to other methods of training used by Monty Roberts during public demonstrations. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses, with the stress response comparable or less than those previously reported in the literature for horses being trained outside of public audience events. Furthermore, we found no evidence that Join-up® alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of horses.Effective training of horses relies on the trainer’s awareness of learning theory and equine ethology, and should be undertaken with skill and time. Some trainers, such as Monty Roberts, share their methods through the medium of public demonstrations. This paper describes the opportunistic analysis of beat-to-beat (RR) intervals and heart rate variability (HRV) of ten horses being used in Monty Roberts’ public demonstrations within the United Kingdom. RR and HRV was measured in the stable before training and during training. The HRV variables standard deviation of the RR interval (SDRR), root mean square of successive RR differences (RMSSD), geometric means standard deviation 1 (SD1) and 2 (SD2), along with the low and high frequency ratio (LF/HF ratio) were calculated. The minimum, average and maximum RR intervals were significantly lower in training (indicative of an increase in heart rate as measured in beats-per-minute) than in the stable (p = 0.0006; p = 0.01; p = 0.03). SDRR, RMSSD, SD1, SD2 and the LF/HF ratio were all significantly lower in training than in the stable (p = 0.001; p = 0.049; p = 0.049; p = 0.001; p = 0.01). When comparing the HR and HRV of horses during Join-up® to overall training, there were no significant differences in any variable with the exception of maximum RR which was significantly lower (p = 0.007) during Join-up®, indicative of short increases in physical exertion (canter) associated with this training exercise. In conclusion, training of horses during public demonstrations is a low-moderate physiological, rather than psychological stressor for horses. The physiological stress responses observed within this study were comparable or less to those previously reported in the literature for horses being trained outside of public audience events. Furthermore, there is no evidence that the use of Join-up® alters HR and HRV in a way to suggest that this training method negatively affects the psychological welfare of horses.

Associations between Heart Rate Variability Parameters and Housing- and Individual-Related Variables in Dairy Cows Using Canonical Correspondence Analysis.

We investigated the associations between heart rate variability (HRV) parameters and some housing- and individual-related variables using the canonical correspondence analysis (CCOA) method in lactating Holstein-Friesian dairy cows. We collected a total of 5200 5-min interbeat interval (IBI) samples from 260 animals on five commercial dairy farms [smaller-scale farms with 70 (Farm 1, n = 50) and 80 cows per farm (Farm 2, n = 40), and larger-scale farms with 850 (Farm 3, n = 66), 1900 (Farm 4, n = 60) and 1200 (Farm 5, n = 45) cows. Dependent variables included HRV parameters, which reflect the activity of the autonomic nervous system: heart rate (HR), the root mean square of successive differences (RMSSD) in IBIs, the standard deviation 1 (SD1), the high frequency (HF) component of HRV and the ratio between the low frequency (LF) and the HF parameter (LF/HF). Explanatory variables were group size, space allowance, milking frequency, parity, daily milk yield, body condition score, locomotion score, farm, season and physical activity (lying, lying and rumination, standing, standing and rumination and feeding). Physical activity involved in standing, feeding and in rumination was associated with HRV parameters, indicating a decreasing sympathetic and an increasing vagal tone in the following order: feeding, standing, standing and rumination, lying and rumination, lying. Objects representing summer positioned close to HR and LF and far from SD1, RMSSD and HF indicate a higher sympathetic and a lower vagal activity. Objects representing autumn, spring and winter associated with increasing vagal activity, in this order. Time-domain measures of HRV were associated with most of the housing- and individual-related explanatory variables. Higher HR and lower RMSSD and SD1 were associated with higher group size, milking frequency, parity and milk yield, and low space allowance. Higher parity and milk yield were associated with higher sympathetic activity as well (higher LF/HF), while individuals with lower locomotion scores (lower degree of lameness) were characterized with a higher sympathetic and a lower vagal tone (higher HR and LF/HF and lower RMSSD and SD1). Our findings indicate that the CCOA method is useful in demonstrating associations between HRV and selected explanatory variables. We consider physical activity, space allowance, group size, milking frequency, parity, daily milk yield, locomotion score and season to be the most important variables in further HRV studies on dairy cows.

Heart Rate Variability as an Indicator of Chronic Stress Caused by Lameness in Dairy Cows.

Most experimental studies on animal stress physiology have focused on acute stress, while chronic stress, which is also encountered in intensive dairy cattle farming–e.g. in case of lameness–, has received little attention. We investigated heart rate (HR) and heart rate variability (HRV) as indicators of the autonomic nervous system activity and fecal glucocorticoid concentrations as the indicator of the hypothalamic–pituitary–adrenal axis activity in lame (with locomotion scores 4 and 5; n = 51) and non-lame (with locomotion scores 1 and 2; n = 52) Holstein-Friesian cows. Data recorded during the periods of undisturbed lying–representing baseline cardiac activity–were involved in the analysis. Besides linear analysis methods of the cardiac inter-beat interval (time-domain geometric, frequency domain and Poincaré analyses) non-linear HRV parameters were also evaluated. With the exception of standard deviation 1 (SD1), all HRV indices were affected by lameness. Heart rate was lower in lame cows than in non-lame ones. Vagal tone parameters were higher in lame cows than in non-lame animals, while indices of the sympathovagal balance reflected on a decreased sympathetic activity in lame cows. All geometric and non-linear HRV measures were lower in lame cows compared to non-lame ones suggesting that chronic stress influenced linear and non-linear characteristics of cardiac function. Lameness had no effect on fecal glucocorticoid concentrations. Our results demonstrate that HRV analysis is a reliable method in the assessment of chronic stress, however, it requires further studies to fully understand the elevated parasympathetic and decreased sympathetic tone in lame animals.

MP15-12 URETHRAL STRICTURE (US) AND ARTIFICIAL URINARY SPHINCTER (AUS) REINSERTION RATES AFTER URETHRAL REPAIR AT THE TIME OF AUS EXPLANTATION FOR EROSION

INTRODUCTION AND OBJECTIVES: Knowledge of urethral stricture anatomy is essential for appropriate surgical management. While retrograde urethrogram is considered the gold standard for evaluation, ultrasound urethrogram has been shown to be more accurate in determining anterior urethral stricture length and extent of spongiofibrosis. To date, ultrasound urethrograms have been primarily performed intra-operatively. We report the results of an outpatient ultrasound urethrogram technique, which eliminates the need for radiation exposure. METHODS: Twelve consecutive adult men presenting for anterior urethral reconstruction from 10/2013-10/2014 underwent outpatient ultrasound urethrogram. Patients were excluded from this study if any urethral imaging has been performed using radiation (retrograde urethrogram or voiding cystourethrogram). The Siemens Acuson S2000 Ultrasound System is used at our institution. Outpatient retrograde ultrasound urethrogram is performed with the patient in the frog-leg position. Lidocaine gel is injected through the meatus to distend the urethra and act as contrast. Linear High-frequency multi-hertz 18L6 and curved multi-hertz 6C2 probes are used to study the penile and bulbar urethra, respectively. Lengths of strictures as determined by outpatient ultrasound urethrogram and direct intra-operative measurements were analyzed by a paired t-test. RESULTS: Table 1 shows the differences between ultrasound urethrogram and intra-operative stricture lengths. The difference between ultrasound urethrogram stricture length measurement (mean1⁄41.7833, standard deviation1⁄40.8892) and intra-operative stricture length measurement (mean1⁄41.7500, standard deviation1⁄41.011) was not significant with t(11)1⁄40.358, p1⁄40.727. Further, the correlation coefficient between the two length measurements is 0.950 (p<0.001). CONCLUSIONS: Our technique of outpatient ultrasound urethrogram for the diagnosis and characterization of anterior urethral strictures is simple, accurate, and eliminates the need for radiation exposure for evaluation of anterior urethral strictures.

Heart rate and heart rate variability in multiparous dairy cows with unassisted calvings in the periparturient period

Behavioural changes before calving can be monitored on farms; however, predicting the onset of calving is sometimes difficult based only on clinical signs. Heart rate (HR) and heart rate variability (HRV) as non-invasive measures of autonomic nervous system (ANS) activity were investigated in Holstein–Friesian cows (N=20) with unassisted calvings in the periparturient period to predict the onset of calving and assess the stress associated with calving. R–R-intervals were analysed in 5-min time windows during the following three main periods of measurement: 1) between 0 and 96h before the onset of calving restlessness (prepartum period); 2) during four stages of calving: (I) early first stage; between the onset of calving restlessness and the first abdominal contractions; (II) late first stage (between the first abdominal contractions and the appearance of the amniotic sac); (III) early second stage (between the appearance of the amniotic sac and the appearance of the foetal hooves); (IV) late second stage (between the appearance of the foetal hooves and delivery of the calf), and 3) over 48h following calving (postpartum period). Data collected between 72 and 96h before calving restlessness was used as baseline. Besides HR, Poincaré measures [standard deviation 1 (SD1) and 2 (SD2) and SD2/SD1 ratio], the root mean square of successive differences (RMSSD) in R–R intervals, the high-frequency (HF) component of HRV and the ratio between the low-frequency (LF) and the HF components (LF/HF ratio) were calculated. Heart rate increased only following the onset of the behavioural signs, peaked before delivery of the calf, then decreased immediately after calving. Parasympathetic indices of HRV (RMSSD, HFnorm and SD1) decreased, whereas sympathovagal indices (LF/HF ratio and SD2/SD1 ratio) increased significantly from baseline between 12 and 24 before the onset of calving restlessness. The same pattern was observed between 0 and 1h before calving restlessness. Following the onset of behavioural signs, parasympathetic activity increased gradually with a parallel shift in sympathovagal balance towards parasympathetic tone, which was possibly a consequence of oxytocin release, which induces an increase in vagus nerve activity. Parasympathetic activity decreased rapidly between 0 and 0.5h following calving and was lower than measured during all other stages of the study, while sympathetic activity peaked during this stage and was higher than measured during any other stages. Between 0 and 4h after calving vagal tone was lower than baseline, whereas sympathovagal balance was higher, reflecting a prolonged physiological challenge caused by calving. Vagal activity decreased, whereas sympathovagal balance shifted towards sympathetic tone with increased live body weight of the calf during the late second stage of calving, suggesting higher levels of stress associated with the higher body weight of calves. All HRV indices, measured either at the late second stage of calving and between 12 and 24h after calving, were affected by the duration of calving. Our results indicate that ANS activity measured by HRV indices is a more immediate indicator of the onset of calving than behaviour or HR, as it changed earlier than when restlessness or elevation in HR could be observed. However, because of the possible effects of other physiological mechanisms (e.g. oxytocin release) on ANS activity it seems to be difficult to measure stress associated with calving by means of HRV between the onset of calving restlessness and delivery. Further research is needed to enable more precise interpretation of the prepartum changes in HR and HRV in dairy cattle.

Association Between Body Mass Index and Suicidal Thoughts and Attempts Among US Adolescents

Association Between Body Mass Index and Suicidal Thoughts and Attempts Among US Adolescents

Changes in cortisol release and heart rate and heart rate variability during the initial training of 3-year-old sport horses

Based on cortisol release, a variety of situations to which domestic horses are exposed have been classified as stressors but studies on the stress during equestrian training are limited. In the present study, Warmblood stallions ( n = 9) and mares ( n = 7) were followed through a 9 respective 12-week initial training program in order to determine potentially stressful training steps. Salivary cortisol concentrations, beat-to-beat (RR) interval and heart rate variability (HRV) were determined. The HRV variables standard deviation of the RR interval (SDRR), RMSSD (root mean square of successive RR differences) and the geometric means standard deviation 1 (SD1) and 2 (SD2) were calculated. Nearly each training unit was associated with an increase in salivary cortisol concentrations ( p < 0.01). Cortisol release varied between training units and occasionally was more pronounced in mares than in stallions ( p < 0.05). The RR interval decreased slightly in response to lunging before mounting of the rider. A pronounced decrease occurred when the rider was mounting, but before the horse showed physical activity ( p < 0.001). The HRV variables SDRR, RMSSD and SD1 decreased in response to training and lowest values were reached during mounting of a rider ( p < 0.001). Thereafter RR interval and HRV variables increased again. In contrast, SD2 increased with the beginning of lunging ( p < 0.05) and no changes in response to mounting were detectable. In conclusion, initial training is a stressor for horses. The most pronounced reaction occurred in response to mounting by a rider, a situation resembling a potentially lethal threat under natural conditions.

Validity of Heart Rate Variability Using Poincare Plot for Assessing Vagal Tone during General Anesthesia

Background: A poincare plot of the heart rate variability (HRV) allows for the quantitative display of the vagal tone in conscious humans. However, relatively little is known about standard deviation 1 (SD1) from the poincare plot reflecting the vagal tone and correlating with the high frequency (HF) spectral power of the HRV during general anesthesia. Thus, the association of SD1 from the poincare plot was examined, along with the HF spectral power of the HRV during general anesthesia. Methods: Beat-to-beat electrocardiograms were recorded for 5 min in 23 patients (isoflurane group, n = 13; sevoflurane group, n = 10) before, during and after general anesthesia. The low frequency (LF) and HF spectral powers, the LF/HF ratio of the HRV and the SD1 and standard deviation 2 (SD2) from the poincare plot were calculated. Results: Both the HF spectral power of the HRV and SD1 from the poincare plot were reduced following general anesthesia, but recovered thereafter. The recovery of both the HF spectral power and SD1 from the poincare plot in the sevoflurane group was faster than those in the isoflurane group. There were strong correlations between the HF spectral power and SD1 before, during and after anesthesia. Conclusions: These data suggest that the SD1 from the poincare plot is a useful and valid parameter for analysis of the vagal tone during general anesthesia.

Change of Heart Rate Variability before and after General Anesthesia

Background: This study assessed the changes in the heart rate variability (HRV) indices, which are used to measure the autonomic nervous system function during general anesthesia (GA), and compared the result of the awake state. Methods: Patients undergoing an explo-laparotomy were anesthetized with either isoflurane (Group I, n = 20) or sevoflurane (Group S, n = 20) added to a mixture of nitrous oxide and oxygen. Frequency-domain analysis of the HRV indices using fast Fourier transformation (FFT) resulted in a power spectrum with a very low (VLF), low (LF), and high frequency (HF) and calculated normalized LF (nuLF), normalized HF (nuHF), and LF/HF ratios before and after GA. Time-domain analysis was performed and the pNN50 (proportion of successive RR intervals [RRI] ＞ 50 ms in relation to the total RRI), RMSSD (root mean square of the successive differences in the RRI), standard deviation 1 (SD1) and standard deviation 2 (SD2) from the Poincare plots, HRV triangular index, and TINN (triangular interpolation of NN interval histogram) were also calculated before and after GA. Results: The VLF, LF, HF, nuLF, and LF/HF ratio during GA decreased by 45.2, 95.1, 83.1, 27.3, and 17.4%, respectively, compared with the awake state. However, the nuHF significantly increased. The RMSSD, pNN50, SD1, SD2, HRV triangular index, and TINN also decreased 62.0, 69.2, 62.0, 61.7, 62.4, and 52.4%, respectively. Groups I and S produced similar alterations in the studied parameters during GA. Conclusions: GA reduced all the HRV indices studied except for the nuHF.

The Effect of Low-Dose Atropine on Hypertensive and Hypotensive Stimuli

Background: Vagal cardiac function plays an important role in cardiovascular homeostasis. The purpose of this study was to investigate the association between vagal cardiac function and changes in blood pressure induced by phenylephrine and by thigh cuff deflation after low-dose atropine (LDA)(/kg) administration. Methods: Beat-to-beat changes in R-R intervals (RRI) and systolic blood pressures (SBP) were measured in 33 healthy volunteers during spontaneous and controlled () breathing before and after LDA administration. The RMSSD (root mean square of successive differences of RRI), pNN50 (proportion of successive RRI > 50 ms in relation to the total RRI), standard deviation 1 (SD1) from Poincare plots, power spectral densities of heart rate variability (HRV) and SBP variability, and spontaneous baroreflex sensitivity (BRS) by transfer function analysis were assessed. Acute hypertension was induced by phenylephrine (/kg), whereas acute hypotension was induced by thigh cuff deflation. Results: RMSSD, pNN50, SD1 of Poincare plots, and the high frequency (HF) power of HRV increased after LDA administration as did spontaneous BRS. Moreover, acute hypertension induced by phenylephrine was significantly attenuated ( to mmHg, P = 0.004) after LDA administration. However, acute hypotension induced by thigh cuff deflation was not significantly changed ( to mmHg, P = 0.62) after LDA administration. Changes in SBP during acute hypertension induced by phenylephrine were significantly correlated with changes in the HF power of HRV (r = 0.60, P