Apomorphine doses impair the reaction time of fast reacting but not slow reacting rats

Previously, several studies in our laboratories have linked the ability to initiate movement rapidly (reactive capacity) in several rat strains to markers of nigrostriatal dopamine function. In the present investigation we wished to determine the extent to which fast-reacting (FR) and slow-reacting (SR) rats responded differentially to the effects of dopamine agonist (apomorphine) administration. Fisher 344 rats were operantly conditioned on a shock-avoidance, reactive capacity task which requires extremely fast, ballistic, lever release responses. In FR, but not in SR rats, significant dose-dependent decreases in the per cent of successful avoidance trials were observed in response to apomorphine doses. Moreover, apomorphine brought responding in the FR animals to levels below that of the SR rats. Performance of the SR rats was unaffected by drug treatments. A number of interpretations are consistent with these preliminary data, including the idea that basal differences in speed of reaction and differential responses to a dopamine agonist, antiparkinsonian agent may both be associated with a similar mechanism; differential activation of compartmentalized striatal efferent systems.     

Effect of premenstrual stress on audiovisual reaction time and audiogram

A study of weight, auditory reaction time (ART), visual reaction time (VRT) and audiogram was carried out on 105 healthy female subjects between the age of 17-20 years during the premenstrual and post-menstrual phase. A significant increase in weight and prolongation in auditory reaction time (ART) and visual reaction time (VRT) were observed during premenstrual phase. A slight increase in decibel loss was also observed during premenstrual phase in audiogram though not significant. These changes could be attributed to fluid and salt retention due to overain steroids leading to decrease in the processing capability of central nervous system.     

Effect of yogasanas on the visual and auditory reaction time

Visual and auditory reaction time (VRT, ART) was studied in 83 healthy male subjects of 30-40 years of age who had never practiced yogasanas before. These subjects were divided into two groups viz. Group A whose VRT and ART was determined after 1 hr. yogasanas and Group B whose ART and VRT was determined after 6 weeks yogasanas training programme. VRT and ART showed a significant reduction in Group A (P less than .05) and Group B (P less than .001).     

Effects of dextroamphetamine on event-related slow potentials in rat cortex during a reaction time task

Event-related slow potentials were recorded from two different cortical areas in the rat during an operant reaction time task in which trials were initiated at variable intervals by an auditory warning stimulus. Slow potential responses during the 2-sec period between onset of the warning stimulus and extension of a retractable lever were analyzed. The effects of various doses of d-Amphetamine on the slow potential responses were examined. Surface-negative slow potential responses from the frontal cortex had two components, an early wave which reached maximum amplitude at 200–350 msec after the stimulus and a later wave which began at 650–850 msec. The slow potential response recorded from the visual cortex showed a smaller surface-negative wave which was maximum at 350–1000 msec; following the initial negative wave, the potential gradually shifted positive. d-Amphetamine (0.25, 0.5 and 1.0 mg/kg) caused a dose-related depression of the frontal slow potential responses (indicated by both amplitude and area analysis). Amplitudes and areas of the visual slow potential were not consistently altered. The results of this study indicate that the effects of d-amphetamine on eventrelated slow potentials in the rat are dependent on the cortical area from which they are recorded.     

Inpatient male alcoholics: Predicting program completion time in days and characteristics of fast and slow completers

This study relates the origin and validation of an hypothesis-based scale that predicted program completion time (PCT) of inpatient male alcoholics within 8.6 days. It comprises 10 statements from an emotional state and demographic questionnaire's 46 items.The new scale is the ratio of interpersonal relations (IR) items to “recovery facilitating” (RF) items: IR/RF. Cross-validation on two groups of 28 male alcoholic completers yielded validities from 0.49 to 0.52. Combining the scale with other data selected by computer from the same questionnaire raised validity to 0.73 (adjusted) and reduced prediction error 19.8% to 6.9 days.The scale's rationale involves relationship dynamics between “internal strength” (RF) and “external behavior” (IR). It is consistent with: pre/post changes in IR/RF; RF; IR; data and interpretations from Edwards Personal Preference Schedule (EPPS) and California Psychological Inventory (CPI) scores; comparisons of contrasting groups. Profiles of high and low scale score groups show both major differences and similarities. Treatment personnel reactions to high score profile content suggest the scale's potential value for planning patient improvement and for reducing non-completer incidence. The nature of the scale's pre/post changes indicates an additional utility: assessing treatment effectiveness.     

Effect of stimulus contrast uncertainty on simple reaction time

Both reaction time (RT) and the latency of the visually evoked potentials (VEP) to grating onset increase with increasing stimulus spatial frequency (SF). At SF higher than 5 c/deg RT increases faster than VEP latency, the difference resulting in a "central delay" (Mihaylova et al., 1999). Due to the equipment limitations, RT and VEP experiments of Mihaylova et al. (1999) differed in constancy of stimulus contrast within a sequence of trials. The present experiments were aimed at testing the assumption that the central delay is a result of contrast uncertainty effect on RT. To this end, RT were measured in condition of both constant and variable grating contrast. The stimuli were sinusoidal gratings ranging in SF from 0.5 to 16 c/deg and in contrast from 2.5 to 50%. In addition, VEP were recorded to the same stimuli in blocks of fixed contrast and the latencies of the early VEP wave were subtracted from RT. Contrast uncertainty did not affect RT at low SF, 0.5 and 2 c/deg, while increasing RT at SF higher than 5 c/deg both at low and high stimulus contrast. The results showed that the central component of RT increase at high SF is reduced but not eliminated under constant contrast condition. The uncertainty effect at high SF might be due to contrast sensitivity reduction, reduced subjective stimulus probability and differences in response strategy adopted by the subjects when contrast was constant or variable. An alternative explanation is a larger ability of low SF stimuli compared to high SF stimuli to attract visual attention.     

Effect of shift working on reaction time in hospital employees

Visual and Auditory reaction time (VRT, ART) were studied in 286 hospital employees during day duty and night duty in the age group of 20 to 60 years to find out the effect of shift working on reaction time in hospital employees. Subjects were presented with two visual stimuli i.e. red and green light and two auditory stimuli, i.e., high pitch and low pitch sound stimuli. The significance of difference of VRT and ART during day duty and night duty was studied with the use of standard error of difference between two means. The statistical difference was determined by 'z' test. VRT during day duty (231.60 +/- 30.93) were less than VRT during night duty (234.98 +/- 32.27) and ART during day duty (224.69 +/- 46.95) were also less than ART during night duty (228.74 +/- 47.01). Our results indicate that reaction time is more during night duty as compared to day duty but the difference is not significant. It may be because of hospital employees get adapted to reduced sleep after working continuously in the shift system.     

Effect of alcohol and monetary reward on visually evoked potentials and reaction time

A dose of alcohol producing a mean blood alcohol concentration of 0.09% slowed the peak of later components of visually evoked potentials recorded from the occipital scalp. Simple visuomotor reaction time was also slower in a low-motivation nonreward condition.     

急诊快捷护理流程对急性脑卒中救治时间及治疗效果的影响

目的 分析急诊快捷护理流程对急性脑卒中救治时间及治疗效果的影响.方法 选择接受治疗的急性脑卒中患者作为研究对象,分别采用常规护理流程及急诊快捷护理流程,比较两组平均接诊时间及急症至手术时间、致残率及死亡率等差异.结果 观察组接诊时间（16.3±1.8） min、急诊至手术时间（45.3±11.0） min均明显短于对照组（P＜0.05）;致残率32.5％、致死率2.4％均低于对照组（P＜0.05）.结论 实施急诊快捷护理流程可有效缩短患者接诊时间及急诊至手术时间,降低致残率及死亡率,具有积极的临床意义.     

Effect of lithium on reaction time — A study of diurnal variations

Continuous reaction time performance was measured in groups of normal controls, psychiatric controls and patients treated with lithium.The reaction times were slower for the patients treated with lithium compared to both groups of controls, but the performance was not impaired to the same degree as in patients with various forms of cerebral dysfunction.For all groups reaction times were slower in the morning than in the evening or at night. Slow reaction times at the first investigation in the groups of normal and psychiatric controls were positively correlated with larger variations in the 24 h course. However, this correlation could not be demonstrated for patients on lithium treatment, probably because these patients do not approach their limit of speed as often as other patients or controls.     

Effect of iron deficiency anemia on audiovisual reaction time in adolescent girls

Adolescent girls are at high risk of developing iron deficiency because of increased iron demands during puberty, menstrual losses, and limited dietary iron intake. This study was carried out to demonstrate the effects of Iron Deficiency Anemia on Audiovisual reaction time in adolescent girls. Adolescent girls between 17-19 years of age with similar socioeconomic background were recruited from college of nursing for the study. They were all screened and categorized into two groups depending on their haemoglobin status. Students having Hb > 12 gm/dl formed the control group i.e. Group I (n=30). All students having Hb < 12 gm/dl and S. Ferritin < 12 microg/dl formed group II i.e. iron deficient anemic (IDA) group. The following haematological parameters were studied Hemoglobin (Hb), MCV, MCH, MCHC (using Sysmex kx-21 Autoanalyser), Serum.Iron, TIBC (Spectrophotometry), Serum.Ferritin (ELISA). Auditory and Visual reaction time were measured by reaction time instrument supplied by Medicaid system, chandigarh. The mean Hb levels in Group I was 12.93 +/- 0.86 and Group II was 10.08 +/- 0.51 (P<0.001). The MCV, MCH, MCHC, S. Iron, S. Ferritin was also significantly less in group II as compared to group I (P<0.001). TIBC was significantly more in group II as compared to group I (P<0.001). Results showed that both ART and VRT were significantly increased (P<0.001) in iron deficient adolescents suggesting a deterioration in sensorimotor performance in anemics.     

Effect of yoga training on reaction time, respiratory endurance and muscle strength.

There is evidence that the practice of yoga improves physical and mental performance. The present investigation was undertaken to study the effect of yoga training on visual and auditory reaction times (RTs), maximum expiratory pressure (MEP), maximum inspiratory pressure (MIP), 40 mmHg test, breath holding time after expiration (BHTexp), breath holding time after inspiration (BHTinsp), and hand grip strength (HGS). Twenty seven student volunteers were given yoga training for 12 weeks. There was a significant (P < 0.001) decrease in visual RT (from 270.0 +/- 6.20 (SE) to 224.81 +/- 5.76 ms) as well as auditory RT (from 194.18 +/- 6.00 to 157.33 +/- 4.85 ms). MEP increased from 92.61 +/- 9.04 to 126.46 +/- 10.75 mmHg, while MIP increased from 72.23 +/- 6.45 to 90.92 +/- 6.03 mmHg, both these changes being statistically significant (P < 0.05). 40 mmHg test and HGS increased significantly (P < 0.001) from 36.57 +/- 2.04 to 53.36 +/- 3.95 s and 13.78 +/- 0.58 to 16.67 +/- 0.49 kg respectively. BHTexp increased from 32.15 +/- 1.41 to 44.53 +/- 3.78s (P < 0.01) and BHTinsp increased from 63.69 +/- 5.38 to 89.07 +/- 9.61 s (P < 0.05). Our results show that yoga practice for 12 weeks results in significant reduction in visual and auditory RTs and significant increase in respiratory pressures, breath holding times and HGS.     

The action of dantrolene sodium on rat fast and slow muscle in vivo.

1. Rats, anaesthetized with urethane, were injected intravenously with dantrolene sodium in a carrier solution of 5% mannitol taken to pH 10 with NaOH. This carrier solution itself was without effect on extrafusal muscle contraction. 2. Dantrolene sodium (5 mg/kg) had a greater depressant action on the twitch contraction of the fast extensor digitorum longus (EDL) muscle than on the slow soleus (SOL) muscle. The EDL twitch was depressed to 25.9% +/- 1.2% (mean + s.e. mean, n = 7) of control whereas the SOL twitch was depressed to 31.3% +/- 0.4% (n = 9). These values were significantly different at the P less than 0.001 level. 3. The twitch contraction time to peak was reduced by approximately 35% in both EDL and SOL by dantrolene sodium. However, the drug reduced the half relaxation time of SOL by approximately 30% but that of EDL was hardly affected. 4. The effect of dantrolene sodium on contractions elicited by repetitive stimulation was dependent upon the stimulation frequency. For the SOL muscle the greater depression was produced at a stimulation frequency of 25 Hz and for EDL at 75 Hz. The minimum of depression was produced for a full fused tetanus for both muscles. 5. The significance of these findings is discussed in terms of the action of dantrolene sodium on motor control in the intact animal.     

Differential effects of ketoprofen on the pharmacokinetics of sulphadimethoxine in fast and slow acetylator rabbits

Intravenously co-administered ketoprofen decreased the plasma concentration of sulpha-dimethoxine (SDM) after intravenous bolus administration to fast acetylator rabbits, and significantly increased the total body clearance (CLtot) and steady-state volume of distribution (Vdss) of SDM. On the other hand, ketoprofen had little effect on the plasma concentration of SDM in slow acetylator rabbits. When SDM was intravenously administered in combination with ketoprofen, an increase in the plasma concentration of N4-acetylsulphadimethoxine, a major metabolite of SDM that strongly displaces SDM from its binding sites, was observed in all rabbits, but the increase was much larger in fast acetylators. We conclude that the acetylation capacity for SDM is a factor determining the pharmacokinetic interaction between SDM and ketoprofen in rabbits.