Effects of d-amphetamine on the behavior of pigeons exposed to the peak procedure

The effects of d-amphetamine on pigeons' key-pecking under the peak interval (PI) procedure were investigated in two experiments. In experiment I the effects of doses of d-amphetamine from 0.75 to 3.0 mg/kg on responding under PI 30 and 45 s were studied for 10 successive days. Reductions in peak time and wait time were observed at both PI values and an increase in the width was found at PI 30 s. There was no evidence of tolerance. In experiment II, pigeons exposed to a PI 45 s schedule were administered doses of D-amphetamine of 1.5 and 3.0 mg/kg for 30 successive days. Reductions in peak time and wait time were found here. Evidence of tolerance was found in wait time, peak time and width of the distribution at the higher dose. In both experiments a rate-dependent effect of the drug was found in the portion of each peak trial before the time that food was delivered on reinforced trials; this effect was weaker after the customary time of food delivery. The rate-dependent effect for responses before food time, combined with little effect of the drug on responses after food time, is shown by simulation to be sufficient to account for the reduction in peak time, without the need to appeal to an internal clock mechanism.     

Circannual Variations of the Bleeding Time in the Rat

This study was carried out to determine the annual fluctuations of the tail bleeding time in the rat. Bleeding time was determined by transection of the tail of pentobarbital-anesthetized rats. Over a 6-year period, monthly measurement of the tail bleeding time revealed highly reproducible circannual fluctuations. Bleeding times were shortened in the summer (414 ± 18 s in July), being almost half that observed during the winter span (886 ± 32 s in January). The difference between these two time points was highly significant (p > 0.001). This study reports for the first time circannual variations of the bleeding time in the rat.     

Characterization of hydrotropism: the timing of perception and signal movement from the root cap in the agravitropic pea mutant ageotropum

In this study, ageotropum pea mutant was used to determine the threshold time for perception of an osmotic stimulation in the root cap and the time requirement for transduction and transmission of the hydrotropic signal from the root cap to the elongation region. The threshold time for the perception of an osmotic stimulation was compared to current estimates of threshold times for graviperception in roots. The time required for transduction and transmission in the hydrotropic response of ageotropum was compared to the time requirement in the gravity response of Alaska pea roots. We determined that threshold time for perception of an osmotic stimulation in the root cap is very rapid, occurring in less than 2 min following the application of sorbitol to the root cap. Furthermore, a single 5 min exposure of sorbitol to the root cap fully induced a hydrotropic response. We also found that transduction and transmission of an osmotic stimulus requires 90-120 min for movement from the root cap to more basal tissues involved in differential growth leading to root curvature. The very rapid threshold time for perception of root hydrotropism is similar to those times reported for root gravitropism. However, the time required for the transduction and transmission of an osmotic stimulation from the root cap is significantly longer than the time required in gravitropism. These results suggest that there must exist some differences between root hydrotropism and gravitropism in either the rate or mechanisms of transduction and transmission of the tropistic signal from the root cap.     

Predictions of mechanical output of the human M. triceps surae on the basis of electromyographic signals: the role of stimulation dynamics

In order to assess the significance of the dynamics of neural control signals for the rise time of muscle moment, simulations of isometric and dynamic plantar flexion contractions were performed using electromyographic signals (EMG signals) of m. triceps surae as input. When excitation dynamics of the muscle model was optimized for an M-wave of the medial head of m. gastrocnemius (GM), the model was able to make reasonable predictions of the rise time of muscle moment during voluntary isometric plantar flexion contractions on the basis of voluntary GM EMG signals. The rise time of muscle moment in the model was for the greater part determined by the amplitude of the first EMG burst. For dynamic jumplike movements of the ankle joint, however, no relationship between rise time of muscle moment in the experiment and muscle moment predicted by the model on the basis of GM EMG signals was found. Since rise time of muscle moment varied over a small range for this movement, it cannot be completely excluded that stimulation dynamics plays a role in control of these simple single-joint movements.     

Application of the Gabor Transform for Analysis of Electromyographic Signals of the Intestine in the Low-Frequency Region

The Gabor transform allows quantitative estimation of the non-stationarity of the electromyographic signal in the low-frequency region with the maxim permissible time–frequency resolution. The calculation of the parameters of the Gabor transform was conducted on different time and frequency intervals to estimate the slow-wave activity of the intestine. It was demonstrated that the efficient size of the 32-s time window, which provides the efficient resolution of the frequency spectrum at 0.01 Hz, is suitable for the accurate study of the change in the frequency of slow waves. The ability to construct the dependence of the change in the frequency of slow waves of electromyograms on time with the specified accuracy was demonstrated.     

The effect of motor activity on the formation and maintenance of the function of time perception in the course of ontogeny

The effect of motor activity on the perception of the duration of time intervals was studied. Seven hundred and ninety-two subjects aged 7–91 years subjectively measured (scaled) time intervals in the range from 1 to 10 s by methods of estimating, production, and cross-modality matching. The accuracy of scaling was estimated from the value of the relative error. The degree of correspondence of subjective time scales to physical ones was determined from the exponent of the psychophysical scaling function. It was shown that the use of methods with a distinct motor component (production) ensures the smallest error of subjective measurement and the formation of the most adequate subjective time scales. It was found that, for subjects of older age groups, motor activity is a factor that promotes the maintenance of the time perception function.     

下腹部手术麻醉中不同靶浓度瑞芬太尼与异丙酚的作用研究

目的研究下腹部手术麻醉患者应用不同靶浓度瑞芬太尼和异丙酚的作用效果。方法将我院收治的下腹部手术麻醉患者为研究对象,并按随机分组法分为3组,均固定瑞芬太尼靶浓度,A组为6ng/ml,B组为8ng/ml,C组为10ng/ml,同时改变异丙酚靶浓度,范围为2~4μg/ml,观察比较各组的麻醉效果。结果 T1时刻A组的收缩压(SBR)高于B组,心率(HR)高于C组,差异有统计学意义(P0.05);而T2、T3时刻比较,A组的SBR以及HR均较B、C组高(P0.05)。随时间推移,去甲肾上腺素(NE)各时点比较,T1时刻A组的NE高于C组,而血清皮质醇(COR)低于B、C组;T2、T3时刻A组的NE均显著高于B、C组,但3组COR变化无显著差异性(P0.05)。C组自主呼吸恢复时间、拔除气管导管时间、指令反应时间和离室时间均较长,而其睁眼时间较短(P0.05)。结论将瑞芬太尼靶浓度调节为8ng/ml,可取得较为明显的麻醉镇痛效果。     

Relationship between the time of the beginning of the anticipatory postural components and the latent period of raising the arm in the vertical posture

The relationships between the anticipatory postural components when standing subjects raised their arms and the latent period (LP) of the motor response determined by the beginning of the deltoid muscle activation were analyzed. The LP range from the least possible to 1 s was analyzed. In the case of short LPs (approximately up to 170 ms), the anticipation time for the ipsilateral biceps femoris muscle (BFM) and sacrospinalis muscle (SSM) increased linearly with the LP; at longer LPs, it did not depend on the LP and was characterized by a wide scatter. In the case of short LPs, the delay time of the beginning of activation of postural muscles in relation to the signal for movement remained constant and was approximately 100 ms for the BFM and 120 ms for the SSM. This is explained by the fact that, with short LPs of motor response, the CNS had insufficient time to complete postural adjustments before the beginning of movement, which resulted in shortening of the anticipation time of the start of change in the activity of postural muscles and, as a consequence, the appearance of an additional initial backward inclination of the body. The results obtained are discussed in the context of organizing the interaction between the regulation of maintaining the vertical posture and the system of movement control.     

Assessment of the post partum Reproductive Performance of the Icelandic Dairy Cow During a 3 Year Period

The time of ovulation, artificial insemination (AI), conception and conception rate were studied in 412 Icelandic dairy cows from 2 different areas during a period of 3 years. To assess these parameters the progesterone level was measured in sequential samples of milk and the status of the genital organs evaluated by monthly rectal palpations. The time and number of AI was recorded and the conception rate calculated and compared with the other parameters. Furthermore, the length of the calving interval and gestation period were determined. The effects of year, season, area, age, herd and parity on these parameters were evaluated. The overall mean for the time of first post partum ovulation was 42 days and varied from 29 to 49 days between herds. This is a considerably longer time than recorded for many other breeds of dairy cows. The effects of season, area and herd were significant for the time of first post partum ovulation. The overall time of first post partum AI and conception were 74 days and 97 days, respectively. In spite of late onset of ovarian activity in Icelandic dairy cows, these two pararmeters are comparable to those of other breeds of cattle. The effects of season, parity and herd were significant for these two parameters. The conception rate to first post partum AI was 59% and the number of AI per conception was 1.6. The time of conception correlated closely (r = 0.5) with the time of first post partum AI, but the conception rate to first AI increased and the number of AI per conception decreased with increasing time of first post partum AI. The calving interval was 382 days and the gestation period was 287 days.     

The ecology of motherhood: the structuring of lactation costs by chacma baboons

1. Data from a long-term study of Papio hamadryas ursinus (L.) in the De Hoop Nature Reserve, Western Cape, South Africa, were used to test the assumptions and predictions of Altmann's model of maternal time budgets. 2. Female baboons' feeding time was below model predictions, and there was no evidence for a consistent increase in feeding time with infant age. In addition, female feeding time was not significantly higher than observed baseline feeding times for nonlactating females. 3. Female baboons reduced activity levels in the first few months post-partum, as reflected in significant increases in resting time, and there was some indication that females lost body mass over the course of lactation. When feeding demand was high, females sacrificed social time, and conserved resting time. 4. Females increased vigilance levels during the first 4 months of infant life and were more vigilant overall during lactation than when nonlactating. There was a negative relationship between feeding time and vigilance, but a positive relationship between resting time and vigilance. 5. Female baboons at De Hoop appear to cope with the energetic costs of lactation by reducing activity levels, although this cannot compensate completely for increased energetic costs. This may not be so much an'energy-sparing' strategy as a response to threats presented by infanticidal males in this population. Females therefore trade-off feeding time against vigilance.     

Measurement and analysis of the shape recovery process of each erythrocyte for estimation of its deformability using the microchannel technique: the influence of the softness of the cell membrane and viscosity of the hemoglobin solution inside the cell

This study tried to evaluate the deformability of each erythrocyte by measuring the time constant of shape recovery just after the erythrocytes left the microchannels. We fabricated a microchannel array with a 5μm-square, 100μm-long cross-section on a PDMS sheet. Three different kinds of blood samples were prepared—healthy erythrocytes as a control, artificially membrane-hardened erythrocytes and artificial hemoglobin solution-diluted erythrocytes—to investigate the influence of erythrocyte's mechanical property changes on the time constant of shape recovery. These shape recovery processes were modeled and analyzed by a standard liner solid model. As a result, the temporal variation of the compressive strain of all erythrocytes showed exponential decay with time elapsed like a first order lag system, so the time constant of shape recovery could be calculated from the semi-logarithmic relaxation curve. The stiffer the cell membrane was using glutaraldehyde, the shorter the time constant for relaxation became compared to healthy erythrocytes. The diluted hemoglobin erythrocytes snapped back quicker than healthy ones. In addition, the time constant of healthy blood drawn from females was clearly shorter than that collected from males. However, the time constant of fully hemoglobin substituted erythrocytes was not affected by gender difference. These results indicate that there is not a significant difference in the stiffness of healthy cell membranes regardless of individual and gender differences. On the other hand, the viscosity of the hemoglobin solution inside the cell is one of the significant factors affecting the time constant. Therefore, these results suggest that the deformability of individual erythrocytes can be quantitated by the time constant for relaxation measured by microchannel techniques.     

Temporal pattern in consumption of the first drink of the day in alcohol-dependent persons

Loss of control over drinking and the craving for alcohol are cardinal signs of alcohol dependence. Our clinical practice indicates that these cravings do not occur randomly during the day, but at the same times each day for the same patient. To validate this hypothesis that alcohol-dependent patients have a circadian rhythmic craving in their desire for their first drink of the day, we asked 217 persons diagnosed as alcohol-dependent according to DSM-IV criteria to complete a questionnaire that surveyed whether this craving occurred at a fixed time each day. Of the respondents, 82% reported it did; 87% of them could state the time of day they consumed their first daily drink; and 80% reported that the time of their first drink of the day did not vary much from one day to the next. The most frequent time of consuming the first drink of alcohol was between 09:00 and 11:00 h, and it was independent of the subjects' sleep-wake routine (the delay between the hours of wake-up and the time of the first urge for alcohol was 3:45 +/- 3:30 h) and lunch or dinner time. This rhythmicity seems to be a pertinent criterion for alcohol dependence syndrome.     

Enclosure environment affects the activity budgets of captive Japanese macaques (Macaca fuscata)

Individuals adapt to changes in their environment, such as food availability and temperature, by adjusting the amount of time spent in different behavioral activities. These adjustments in behavior should vary across age-sex class according to specific physiological and social needs. We studied the activity budgets of three social Japanese macaque groups inhabiting either vegetated or nonvegetated enclosures in order to compare the effects of access with vegetation, as both food and substrate on resting, feeding, grooming and moving activities over a 12-month period. Daily access to natural foods for monkeys in the vegetated enclosure seems to be largely responsible for the differences in daily time budgets of these three groups. Resting time in all three groups was longer than the time devoted to other activities. Resting and moving time in the two nonvegetated enclosures was significantly longer than in the vegetated enclosure. In contrast, feeding and grooming time was significantly longer in the vegetated enclosure. Seasonal variation in time spent feeding, resting and grooming was significantly effected by enclosure type. In all three enclosures, immatures, particularly females, spent more time feeding and moving, whereas adults spent more time resting. Significant monthly variation in time spent by age-sex class was noted only for feeding and resting. Interestingly, in the vegetated enclosure, time spent feeding on natural vegetation was equal to the amount of time spent feeding on provisioned food. This suggests that factors other than energetic and nutritional needs may be important determinants of the activity budget of the species. These results have important implications for the enrichment of captive primates and our understanding of the maintenance of activity patterns by primates in the wild.     

Factors Affecting the Timing of Signal Detection of Adverse Drug Reactions

We investigated factors affecting the timing of signal detection by comparing variations in reporting time of known and unknown ADRs after initial drug release in the USA. Data on adverse event reactions (AERs) submitted to U.S. FDA was used. Six ADRs associated with 6 drugs (rosuvastatin, aripiprazole, teriparatide, telithromycin, exenatide, varenicline) were investigated: Changes in the proportional reporting ratio, reporting odds ratio, and information component as indexes of signal detection were followed every 3 months after each drugs release, and the time for detection of signals was investigated. The time for the detection of signal to be detected after drug release in the USA was 2–10 months for known ADRs and 19–44 months for unknown ones. The median lag time for known and unknown ADRs was 99.0–122.5 days and 185.5–306.0 days, respectively. When the FDA released advisory information on rare but potentially serious health risks of an unknown ADR, the time lag to report from the onset of ADRs to the FDA was shorter. This study suggested that one factor affecting signal detection time is whether an ADR was known or unknown at release.     

Effective tempo of the step test for dynamic balance ability in the elderly

This study aimed to examine the reliability and sex- and age-related differences of step tests with stipulated tempos as well as to clarify useful test parameters and tempos. One hundred forty elderly people and fifty young adults conducted tapping and stepping tests, matching the tempo provided by a metronome. Both tests involve movements where the subject touches a sheet with both the right and left hands or right and left legs at a designated spot. Evaluation parameters were the time difference between the beep sound and the time at which the sheet was touched in both tests as well as two-leg support and one-leg support times in the step test. The trial-to-trial reliability of the parameters in both tests was high. The time differences of both 40 bpm tests in the elderly were larger in males than in females. In the step test, the time difference and two-leg support times of the elderly were larger, in the order of 40, 60, and 120 bpm, and the one-leg support time was less in 40 bpm than 60 bpm or 120 bpm. The one-leg support time of the young subjects was larger, in the order of 40, 60, and 120 bpm. A significant age-related difference was found in the 40 bpm and 60 bpm test, and the time difference and two-leg support time were larger in the elderly while the one-leg support time was larger in the young subjects. The time difference at 40 bpm in the elderly was larger in the step test than in the tap test. There was no significant difference between both tests in the young subjects. In conclusion, the step test with the slow tempo, because it requires a long one-leg support phase, is effective for evaluating dynamic balance in the elderly. The time difference and two-leg and one-leg support times are effective evaluation parameters of the step test.     

Muscle Compliance and the Longitudinal Transmission of Mechanical Impulses

The time required for a mechanical impulse to propagate from one end to the other was measured directly in frog sartorius muscles and in fiber bundles from the semitendinosus muscle. When the fibers were fully activated, the transmission velocity was 170 mm/ms. In resting fibers the transmission time was three to four times greater than in activated fibers. Control experiments indicated that the transmission time across the tendons was negligible. A muscle compliance of 55–80 Å per half sarcomere was estimated from these data. The "measurement time" of the method was calculated to be about 15 µs. This relatively short measurement time makes the method potentially useful for detecting changes in cross-bridge compliance.     

A quantitative comparison of the effects of intracellular calcium injection and light adaptation on the photoresponse of Limulus ventral photoreceptors

Calcium ions were iontophoretically injected into ventral photoreceptors of Limulus by passing current between two intracellular pipettes. Changes in sensitivity and photoresponse time course were measured for both light adaptation and Ca++ injection. We found for some photoreceptors that there was no significant difference in the photoresponse time course for desensitization produced by light adaptation or by Ca++ injection. In other photoreceptors, the time delay of photoresponse for Ca++ injection was slightly longer than for light adaptation. The variability of threshold response amplitude and time delay decreases when the photoreceptor is desensitized by either light adaptation or Ca++ injection. The peak amplitude versus log stimulus intensity relationships for controls, light adaptation, and Ca++ injection all could be described very closely by a single template curve shifted along the log intensity axis. A 40- to 50-fold change in sensitivity is associated with a 2-fold change in photoresponse time delay for both light adaptation and Ca++ injection.     

天山瓦韦总黄酮成分的含量测定

目的:对天山瓦韦总黄酮成分进行含量测定。方法:以芦丁为标样,用分光光度法测定不同溶剂和不同时间条件下的总黄酮含量。结果:天山瓦韦中黄酮类化合物提取的最佳条件为:75%的乙醇,抽提3.5h,总黄酮含量为3.20%。     

Perturbation analysis of the voltage-sensitive conformational changes of the Na+/glucose cotransporter

Conformational changes of the human Na(+)/glucose cotransporter (hSGLT1) were studied using voltage-jump methods. The cotransporter was expressed in Xenopus laevis oocytes, and SGLT1 charge movements were measured in the micro- to millisecond time scale using the cut-open oocyte preparation and in the millisecond to second time scale using the two-electrode voltage clamp method. Simultaneous charge and fluorescence changes were studied using tetramethylrhodamine-6-maleimide-labeled hSGLT1 Q457C. In 100 mM external [Na(+)], depolarizing voltage steps evoked a charge movement that rose initially to a peak (with time constant tau = 0.17 ms) before decaying to steady state with two time constants (tau = 2-30 and 25-150 ms). The time to peak (0.9 ms) decreased with [Na(+)], and was not observed in 0 mM [Na(+)]. In absence of Na(+), charge movement decayed monotonically to steady state with three time constants (0.2, 2, and 150 ms). Charge movement was accompanied by fluorescence changes with similar time courses, indicating that global conformational changes monitored by charge movement are reflected by local environmental changes at or near Q457C. Our results indicate that the major voltage-dependent step of the Na(+)/glucose transport cycle is the return of the empty carrier from inward to outward facing conformations. Finally, we observed subtle differences between time constants for charge movement and for optical changes, suggesting that optical recordings can be used to monitor local conformational changes that underlie the global conformational changes of cotransporters.     

Relationship between the proliferation waves of the hepatocytes after hepatectomy and the waves of diurnal rhythm of mitotic activity. 1. Dependence of the form of the mitotic wave and the time of attaining its maximal degree on the time of operation]

The diurnal rhythm of mitotic activity (MA) of intact animal hepatocytes and the proliferative wave of hepatocytes after partial hepatactomy at time t0 are thought to appear as a result of formation of an initial proliferative wave, Pk-wave, within the G0-phase at constant moments of the day--time tk+1=tk+TMA(TMA=24hrs/K, k=1, or 2, . . ., or K) under the influence of the regulating system of the organism. Cells of the Pk-wave pass during a short time deltat (deltat less than TMA) from the G0-phase into the transformation phase, and then into the G1-phase. The 1st stimulated proliferative wave is formed at time tk, if tk--TMA less than t0 less than or equal to tk; its intensity depends most likely on the intensity of the corresponding Pk-wave of the intact liver. It was noted that time t0 of partial hepatectomy was necessary to coordinate with tk, but not with the time of the maximal mitotic activity, and that it was necessary to hepatectomize all animals within the interval from time tk--TMA to time tk. The model was shown to compare well with data by Post et al. (1963), Barbason (1970), and Van Cantfort and Barbason (1972) for hepatocytes of Wistar rats with TMA=8hrs, and tk (k=1,2,3) within intervals (2 a.m.; 4 a.m), (10 p.m.; noon), and (6 p.m. 8 p.m.). The maximal rate of liver generation was observed for all the hepactomized animals with the time of operation being between 8 p. m. and 2 a.m.