Comparison of feed intake behaviour and stress response in isolated and non-isolated African catfish

This study shows that in African catfish Clarias gariepinus feed intake ( I _F) is stimulated by the presence of conspecifics resulting in higher I _F and growth rate. The feeding duration and the frequency of feeding acts were lower in isolated fish as compared with non-isolated fish, indicating a decreased feeding motivation when fish are held individually. Isolation per se , however, seems not to act as a stressor in the short-term or to affect the stress response, probably because periods of isolation are part of the African catfish lifestyle.     

Assessment of tissue damaging effects of mixed micellar absorption enhancers on the intestinal mucosa of common carp (Cyprinus carpio), African catfish (Clarias gariepinus) and rainbow trout (Oncorhynchus mykiss) as a consequence of enhanced intestinal absorption of sGnRH-a

Non-ionic surfactant–polyoxyethylene sorbitan monooleate (Tween-80) and oleic acid are food and pharmaceutical ingredients for oral and parenteral delivery and generally regarded as safe (GRAS). They have the potential as an intestinal absorption enhancer for the development of oral drug delivery systems. However, their safety in terms of mucosal integrity has yet to be evaluated. Therefore, the purpose of the present work was to study the tissue damaging effects of Tween-80, oleic acid and of their mixed micellar formulation (oleic acid + Tween-80). This was investigated at 2 h and 24 h after rectal delivery and compared with the topical effect of polyoxyethylene 9 lauryl ether (Polydocanol). The same experiment was carried out on three species with distinct feeding habits: the common carp, Cyprinus carpio (L.); the African catfish, Clarias gariepinus (Burchell); and the rainbow trout, Oncorhynchus mykiss (Walb.). Based on the findings of this study it was concluded that Tween-80 (4%), or its mixed micelle with oleic acid (0.6%) can be considered as a safe formulation, inducing only a moderate alteration of the intestinal mucosa, comparable to the effect of an isotonic saline. By contrast, in the three species, the same dose of Polydocanol, or of its mixed micelle with oleic acid, induced severe tissue damage of the intestinal mucosa, still present after 24 h. Mixed micelles of oleic acid with Tween-80 were also demonstrated as increasing the intestinal absorption of the salmon gonadotropin releasing hormone analogue (sGnRH-a) in catfish, C. gariepinus , and consequently stimulating GtH II secretion. This effect was compared with the action of other drugs considered as intestinal absorption enhancers.     

Sleepiness and Sleep in a Simulated “Six Hours On/Six Hours Off” Sea Watch System

Ships are operated around the clock using rapidly rotating shift schedules called sea watch systems. Sea watch systems may cause fatigue, in the same way as other irregular working time arrangements. The present study investigated subjective sleepiness and sleep duration in connection with a 6 h on/6 h off duty system. The study was performed in a bridge simulator, very similar to those found on ships. Twelve officers divided into two groups participated in the study that lasted 66 h. Half of the subjects started with the 06:00–12:00 h watch and the other half with the 12:00–18:00 h watch. The subjects alternated between off‐duty and on‐duty for the remainder of the experimental period. Approximately halfway through the experiment, the 12:00–18:00 h watch was divided into two 3 h watches/off‐duty periods. The effect of this was to reverse the on‐duty/off‐duty pattern between the two groups. This enabled all subjects to work the four possible watches (00:00–06:00 h, 06:00–12:00 h, 12:00–18:00 h, and 18:00–24:00 h) in an order that was essentially counterbalanced between groups. Ratings of sleepiness (Karolinska Sleepiness Scale; KSS) were obtained every 30 min during on‐duty periods and if subjects were awake during off‐duty periods. The subjectively rated duration of sleep was recorded after each off‐duty period that preceded watch periods when KSS was rated. The results showed that the average level of sleepiness was significantly higher during the 00:00–06:00 h watch compared to the 12:00–18:00 h and 18:00–24:00 h watches, but not to the 06:00–12:00 h watch. Sleepiness also progressed significantly from the start toward the end of each watch, with the exception of the 06:00‐12:00 h watch, when levels remained approximately stable. There were no differences between groups (i.e., the order between watches). Sleep duration during the 06:00–12:00 h off‐duty period (3 h 29 min) was significantly longer than during the 12:00–18:00 h period (1 h 47 min) and the 18:00–24:00 h period (2 h 7 min). Sleep during the 00:00–06:00 h period (4 h 23 min) was longer than all sleep periods except the 06:00–12:00 h period. There were no differences between groups. In spite of sufficient opportunities for sleep, sleep was on the average around 1–1 h 30 min shorter than the 7–7 h 30 min that is considered “normal” during a 24 h period. This is probably a consequence of the difficulty to sleep during daytime due to the alerting effects of the circadian rhythm. Also, sleepiness during the night and early mornings reached high levels, which may be explained by a combination of working close to or during the circadian trough of alertness and the relatively short sleep periods obtained. An initial suppression of sleepiness was observed during all watches, except for the 06:00–12:00 h watch. This suppression may be explained by the “masking effect” exerted by the relative high levels of activity required when taking over the responsibility of the ship. Toward the end of watches, the levels of sleepiness progressively increased to relatively high levels, at least during the 00:00–06:00 h watch. Presumably, initially high levels of activity are replaced by routine and even boredom.     

Effect of fasting and repeat feeding on metabolic rate in Southern Catfish,Silurus meridionalis chen

Southern catfish juvenile (37.6-65.9 g) were fasted for two weeks and fed with cutlets of freshly killed loach species at 2% body mass per meal twice daily (06:00 and 18:00) for four days at 27.5°C. Metabolic rates were measured during the fasting and feeding periods and all metabolic rates were adjusted to a standard body mass of 1 kg using an exponent of 0.75. The aim of this study was to investigate the effect of fasting and repeat feeding on the resting metabolic rate and the feeding metabolic rate. The results demonstrated that the standardized value of the resting metabolic rate gradually decreased from 69.6 ± 2.7 (means ± S.E.) to 42.8 ± 2.3 mgO2 h-1 during the two weeks of fasting. The peak feeding metabolic rate and average metabolic rate of each feeding (12 h) gradually increased with repeat feeding before leveling off. The results of this study suggest that southern catfish can regulate digestive function and gradually alter the characteristics of metabolism according to the availability of a food resource.     

Sleepiness and sleep in a simulated "six hours on/six hours off" sea watch system

Ships are operated around the clock using rapidly rotating shift schedules called sea watch systems. Sea watch systems may cause fatigue, in the same way as other irregular working time arrangements. The present study investigated subjective sleepiness and sleep duration in connection with a 6 h on/6 h off duty system. The study was performed in a bridge simulator, very similar to those found on ships. Twelve officers divided into two groups participated in the study that lasted 66 h. Half of the subjects started with the 06:00-12:00 h watch and the other half with the 12:00-18:00 h watch. The subjects alternated between off-duty and on-duty for the remainder of the experimental period. Approximately halfway through the experiment, the 12:00-18:00 h watch was divided into two 3 h watches/off-duty periods. The effect of this was to reverse the on-duty/off-duty pattern between the two groups. This enabled all subjects to work the four possible watches (00:00-06:00 h, 06:00-12:00 h, 12:00-18:00 h, and 18:00-24:00 h) in an order that was essentially counterbalanced between groups. Ratings of sleepiness (Karolinska Sleepiness Scale; KSS) were obtained every 30 min during on-duty periods and if subjects were awake during off-duty periods. The subjectively rated duration of sleep was recorded after each off-duty period that preceded watch periods when KSS was rated. The results showed that the average level of sleepiness was significantly higher during the 00:00-06:00 h watch compared to the 12:00-18:00 h and 18:00-24:00 h watches, but not to the 06:00-12:00 h watch. Sleepiness also progressed significantly from the start toward the end of each watch, with the exception of the 06:00-12:00 h watch, when levels remained approximately stable. There were no differences between groups (i.e., the order between watches). Sleep duration during the 06:00-12:00 h off-duty period (3 h 29 min) was significantly longer than during the 12:00-18:00 h period (1 h 47 min) and the 18:00-24:00 h period (2 h 7 min). Sleep during the 00:00-06:00 h period (4 h 23 min) was longer than all sleep periods except the 06:00-12:00 h period. There were no differences between groups. In spite of sufficient opportunities for sleep, sleep was on the average around 1-1 h 30 min shorter than the 7-7 h 30 min that is considered “normal” during a 24 h period. This is probably a consequence of the difficulty to sleep during daytime due to the alerting effects of the circadian rhythm. Also, sleepiness during the night and early mornings reached high levels, which may be explained by a combination of working close to or during the circadian trough of alertness and the relatively short sleep periods obtained. An initial suppression of sleepiness was observed during all watches, except for the 06:00-12:00 h watch. This suppression may be explained by the “masking effect” exerted by the relative high levels of activity required when taking over the responsibility of the ship. Toward the end of watches, the levels of sleepiness progressively increased to relatively high levels, at least during the 00:00-06:00 h watch. Presumably, initially high levels of activity are replaced by routine and even boredom.     

Circadian rhythms may not influence the outcomes of thrombolysis in patients with ischemic stroke: A study from China

ABSTRACT

Circadian rhythms can affect physical or mental activities as well as the time of stroke onset. The impact of circadian rhythms on acute ischemic stroke (AIS) patients treated by recombinant alteplase (rt-PA) is still incongruent. This study aims to consider whether the outcomes of thrombolysis differ depending on stroke onset time and rt-PA infusion time in patients with AIS. A total of 447 AIS patients, who underwent rt-PA intravenous infusion within 4.5 hours after stroke onset, were enrolled in this study consecutively from June 2010 through December 2016. All of the patients were grouped based on the stroke onset time and rt-PA infusion time into two exact 12-hour intervals as daytime (06:01–18:00) and nighttime (18:01–06:00) and further divided into four subgroups at 6-hour time intervals (00:01–06:00, 06:01–12:00, 12:01–18:00 and 18:01–24:00). Major neurological improvement at 1 hour, 24 hours and 7 days, 7-day mortality rate and 24-hour hemorrhage transformation was recorded. The results showed that a total of 295 patients (66.4%) appeared with AIS and 252 (56.4%) were treated during daytime. Higher NIHSS at admission was observed when stroke occurred in nighttime, especially during 00:01–06:00. Patients with stroke onset in nighttime especially during 18:01–24:00 had a significant shorter onset-door time and onset-needle time. No differences of the major neurological improvement at 1 hour, 24 hours and 7 days, 24-hour hemorrhagic transformation and 7-day fatality rate were found among either 12-hour time frames or 6-hour time frames according to the time of stroke onset or rt-PA infusion. In conclusion, there was no evidence to predict that circadian rhythms could influence the outcomes of AIS patients treated with rt-PA in China, although stroke onset during nighttime might aggravate neurological impairment before treatment. Further, multicenter and prospective clinical trials with larger number of subjects are still needed to draw more reliable conclusions.     

Effect of fasting and repeat feeding on metabolic rate in Southern Catfish, Silurus meridionalis chen

Southern catfish juvenile (37.6-65.9 g) were fasted for two weeks and fed with cutlets of freshly killed loach species at 2% body mass per meal twice daily (06:00 and 18:00) for four days at 27.5°C. Metabolic rates were measured during the fasting and feeding periods and all metabolic rates were adjusted to a standard body mass of 1 kg using an exponent of 0.75. The aim of this study was to investigate the effect of fasting and repeat feeding on the resting metabolic rate and the feeding metabolic rate. The results demonstrated that the standardized value of the resting metabolic rate gradually decreased from 69.6 ± 2.7 (means ± S.E.) to 42.8 ± 2.3 mgO₂ h^-1 during the two weeks of fasting. The peak feeding metabolic rate and average metabolic rate of each feeding (12 h) gradually increased with repeat feeding before leveling off. The results of this study suggest that southern catfish can regulate digestive function and gradually alter the characteristics of metabolism according to the availability of a food resource.     

Effects of floor-feeding and the presence of a foraging substrate on the behaviour and stress physiological response of individually housed gilts

Both restricted feeding and barren housing have a negative influence on sow welfare. The aim of this study was to test whether sows that have to search for their feed in a substrate on the floor show less stereotyped (and other abnormal) behaviour and have a lower physiological stress response. In three batches, 96 gilts were housed individually in two rooms in 3.1 m² pens with 1.9 m² solid floor. In a 2×2 factorial design either wood shavings (S) or no substrate (NS) were provided on the floor, and 900 g of feed was provided twice daily (06:30 and 15:00 h) either in a trough (T) or on the floor (F). In weeks 8–12, behaviour was scan-sampled once in the periods 07:00–09:00 h (P1), 10:00–12:00 h (P2), and 13:00–15:00 h (P3). Data from the 5 weeks were pooled per animal. Video recordings (24 h) in week 12 or 13 were scan-sampled for ‘standing’. Saliva samples were taken in week 11 at 2 h intervals during 24 h and measured for cortisol. Spontaneously voided morning-urine was sampled in weeks 2, 7 and 12 or 13 for determination of ratios of adrenaline (A) and noradrenaline (NA) with creatinine (CR). Most effects that were found were due to substrate presence. Main findings were that compared with S-animals, NS-animals stood more during the dark period (4.8% versus 3.0%; P<0.05) and showed more (visible) oral behaviour in P1 (56.8% versus 47.6%; P<0.05), P2 (35.8% versus 30.8%; tendency) and P3 (44.1% versus 33.8%; P<0.05). This included more sham chewing in P1 (tendency), P2 and P3, more pen manipulation in P3, and more other oral behaviour (e.g. teeth grinding) in P1 (tendency) and P2. They had higher cortisol levels before feeding (peaks) and in the early evening (24 h average: 1.49 ng/ml versus 1.02 ng/ml; P<0.05) and higher NA/CR ratios in weeks 7 (tendency) and 12 (5.5 ng/mg versus 3.7 ng/mg; P<0.05). No treatment effects were found on A/CR ratios. Substantial interactive effects of feeding method and substrate were only found in floor manipulation. In all three periods NS-T-animals manipulated the floor less than other animals, probably because they had no attraction to the floor and were not rewarded for searching. Results imply that the presence of a substrate on the floor improves welfare, whereas provision of feed in the substrate in order to stimulate foraging behaviour is of less importance.     

Differences in Sleep,Light, and Circadian Phase in Offshore 18:00–06:00 h and 19:00–07:00 h Shift Workers

Complaints concerning sleep are high among those who work night shifts; this is in part due to the disturbed relationship between circadian phase and the timing of the sleep‐wake cycle. Shift schedule, light exposure, and age are all known to affect adaptation to the night shift. This study investigated circadian phase, sleep, and light exposure in subjects working 18:00–06:00 h and 19:00–07:00 h schedules during summer (May–August). Ten men, aged 46±10 yrs (mean±SD), worked the 19:00–07:00 h shift schedule for two or three weeks offshore (58°N). Seven men, mean age 41±12 yrs, worked the 18:00–06:00 h shift schedule for two weeks offshore (61°N). Circadian phase was assessed by calculating the peak (acrophase) of the 6‐sulphatoxymelatonin rhythm measured by radioimmunoassay of sequential urine samples collected for 72 h at the end of the night shift. Objective sleep and light exposure were assessed by actigraphy and subjective sleep diaries. Subjects working 18:00–06:00 h had a 6‐sulphatoxymelatonin acrophase of 11.7±0.77 h (mean±SEM, decimal hours), whereas it was significantly later, 14.6±0.55 h (p=0.01), for adapted subjects working 19:00–07:00 h. Two subjects did not adapt to the 19:00–07:00 h night shift (6‐sulphatoxymelatonin acrophases being 4.3±0.22 and 5.3±0.29 h). Actigraphy analysis of sleep duration showed significant differences (p=0.03), with a mean sleep duration for those working 19:00–07:00 h of 5.71±0.31 h compared to those working 18:00–06:00 h whose mean sleep duration was 6.64±0.33 h. There was a trend to higher morning light exposure (p=0.07) in the 19:00–07:00 h group. Circadian phase was later (delayed on average by 3 h) and objective sleep was shorter with the 19:00–07:00 h than the 18:00–06:00 h shift schedule. In these offshore conditions in summer, the earlier shift start and end time appears to favor daytime sleep.     

The effect of emersion and handling on the nitrogen excretion rates of Clarias gariepinus

African catfish Clarias gariepinus (=119.9&30.6 g) were exposed to periods of emersion (5, 30, 60, 90 and 180 min) and the ammonia and nitrogen excretion rates measured following re-immersion. Immediately following re-immersion (0–30 min), the ammonia excretion and relative ammonia excretion was greatest for the 5-min emersion gro up. Exposure to extended periods of emersion resulted in a decrease in total nitrogen excretion, notably ammonia excretion, although no significant changes were observed in the non-ammonia component of C. gariepinus .     

秦岭羚牛春夏季昼夜活动节律与时间分配

1996年4~8月,在陕西省佛坪自然保护区内采用无线电遥测技术对4只秦岭羚牛（Budorcas taxicolor bedfordi）的活动规律进行了研究。春夏季羚牛的活动规律以白昼活动为主。羚牛每昼夜有69.95+11.06%的时间处于活动状态（n=40）,其中76.77%的活动时间是在日出后到日落前的白昼。白昼有3个活动高峰期,分别出现在06:00~08:00、10：00~12：00、18：00~20：00 3个时间段。在夜间羚牛只有1个活动高峰期,通常出现在24：00至次日凌晨01：00的时间段。野外观察证实,羚牛白昼的3个活动高峰期与羚牛群体活跃采食的时间吻合。羚牛的昼夜活动节律的形成与变化,可能会受到诸如光照、温度、雨等气候条件的影响。每天的黎明阶段（06：00~07：00）及黄昏阶段（18：30~19：30）是羚牛活动最频繁的时候,平均活动率在90%以上。大雨期间羚牛常常站立或卧地休息。此外,羚牛昼夜活动节律和时间分配方面的差异在年龄上也有所体现。     

Differences in sleep, light, and circadian phase in offshore 18:00-06:00 h and 19:00-07:00 h shift workers

Complaints concerning sleep are high among those who work night shifts; this is in part due to the disturbed relationship between circadian phase and the timing of the sleep-wake cycle. Shift schedule, light exposure, and age are all known to affect adaptation to the night shift. This study investigated circadian phase, sleep, and light exposure in subjects working 18:00-06:00 h and 19:00-07:00 h schedules during summer (May-August). Ten men, aged 46+/-10 yrs (mean+/-SD), worked the 19:00-07:00 h shift schedule for two or three weeks offshore (58 degrees N). Seven men, mean age 41+/-12 yrs, worked the 18:00-06:00 h shift schedule for two weeks offshore (61 degrees N). Circadian phase was assessed by calculating the peak (acrophase) of the 6-sulphatoxymelatonin rhythm measured by radioimmunoassay of sequential urine samples collected for 72 h at the end of the night shift. Objective sleep and light exposure were assessed by actigraphy and subjective sleep diaries. Subjects working 18:00-06:00 h had a 6-sulphatoxymelatonin acrophase of 11.7+/-0.77 h (mean+/-SEM, decimal hours), whereas it was significantly later, 14.6+/-0.55 h (p=0.01), for adapted subjects working 19:00-07:00 h. Two subjects did not adapt to the 19:00-07:00 h night shift (6-sulphatoxymelatonin acrophases being 4.3+/-0.22 and 5.3+/-0.29 h). Actigraphy analysis of sleep duration showed significant differences (p=0.03), with a mean sleep duration for those working 19:00-07:00 h of 5.71+/-0.31 h compared to those working 18:00-06:00 h whose mean sleep duration was 6.64+/-0.33 h. There was a trend to higher morning light exposure (p=0.07) in the 19:00-07:00 h group. Circadian phase was later (delayed on average by 3 h) and objective sleep was shorter with the 19:00-07:00 h than the 18:00-06:00 h shift schedule. In these offshore conditions in summer, the earlier shift start and end time appears to favor daytime sleep.     

Effect of feeding and lack of food on the growth, gross biochemical and fatty acid composition of juvenile catfish

The effect of feeding and starvation on growth, gross body composition and fatty acid composition of body muscle and liver were investigated in juvenile African catfish ( Clarias gariepinus ). The relative composition of fatty acids was influenced by starvation. In both liver and muscle there were marked relative decreases of 14: 0, 16: 1n9 and 18: 1n9 fatty acids and relative increases of 20: 5n3 and 22: 6n3 when these were compared to the controls. Preference of utilization of fatty acids from liver and body muscle during starvation was highest for 14: 0>16: 1n9>18: 1n9 and conservation highest for 22: 6n3>20: 5n3. The changes of these fatty acids were smaller in muscle than in the liver.     

Use of soybean flour (dehulled, solvent-extracted soybean) as a fish meal substitute in practical diets for African catfish, Clarias gariepinus (Burchell 1822): growth, feed utilization and digestibility

Growth and digestibility trials were conducted using African catfish, Clarias gariepinus (Burchell 1822): (1) to obtain apparent digestibility coefficient (ADC) values for capelin fish meal, soybean flour and corn meal; (2) to formulate diets based on ADC values of the protein feedstuffs; and (3) to evaluate the effects of replacing 25%, 50% and 75% of fish meal in control diets with soybean flour on growth, feed utilization efficiency and carcass composition. Supplemental methionine was added to the diet formulation in which soybean flour replaced 75% of the diet. Diets were formulated (400 g digestible protein kg⁻¹ and 15 kJ digestible energy g⁻¹ dry diet) and fed to catfish fingerlings (13.1 ± 0.5 g) to apparent satiation twice daily for 70 days. The protein and energy digestibilities of fish meal and soybean flour were high (>90% and >80%, respectively; P < 0.05). At 75% fish meal replacement with soybean flour (without methionine supplementation), growth and feed utilization efficiency indicators were depressed compared with other diet treatments which had a similar (P > 0.05) growth and feed utilization efficiency to those fed the control diet. The carcass compositions of catfish in all diets were similar (P > 0.05) and the liver histology of catfish fed any of the diets showed no alterations. The results obtained indicate that 50% of fish meal protein in practical catfish diets can be replaced with soybean flour and that catfish can effectively utilize supplemental methionine, thereby allowing up to 75% of the dietary fish meal protein to be replaced by soybean flour.     

鳜肝脏和心脏生物钟基因表达节律分析

在12h光照、12h黑暗交替(Light-Dark; LD)光制下,研究分析了褪黑素和皮质醇水平在鳜血清中的昼夜变化规律,以及13个生物钟基因(Arntl1、Clock、Cry1a、Cry3、Cry-dash、Npas2、Npas4、Nr1d1、Nr1d2、Per1、Per3、Rora和Tim)在鳜(Siniperca chuatsi)肝脏和心脏中的昼夜表达规律。试验在一昼夜内的ZT0(06:00)、ZT3(09:00),ZT6(12:00),ZT9(15:00),ZT12(18:00),ZT15(21:00),ZT18(24:00),ZT21(03:00,2nd d),ZT24(06:00,2nd d) (Zone time,ZT) 9个时间点随机抽取3尾鳜采集其血清、肝脏和心脏。经SPSS 单因素方差分析和Matlab余弦分析,结果显示: 鳜血清中褪黑素和皮质醇含量均呈现出昼夜节律性振荡,褪黑素含量白天显著降低(P0.05),夜间显著上升,皮质醇含量白天缓慢降低,夜间ZT15(21:00)-ZT18(24:00)显著升高,随后开始缓慢降低; 两种激素最低相位都为ZT15(21:00)。在13个生物钟基因中,Cry-dash、Npas4、Nr1d1、Per1和Tim 5个基因在鳜肝脏内具有明显的昼夜节律性,其中Npas4、Nr1d1、Per1、Tim的表达规律相似,皆呈现出光照阶段表达降低,黑暗阶段表达升高的趋势; 但Cry-dash则表现出光照阶段先升高后降低,黑暗阶段先降低后升高的规律。在鳜心脏中,Arntl1、Clock、Cry1a、Npas2、Nr1d1、Nr1d2、Per3、Rora和Tim 9个基因都表现出明显的昼夜节律,表达趋势分为两种: Arntl1、Clock、Nr1d2的表达量在光照阶段降低,黑暗阶段升高; 而Cry1a、Npas2、Nr1d1、Per3、Rora和Tim的表达量在ZT0(06:00)-ZT15(21:00)持续低水平,ZT15(21:00)-ZT18(24:00)表达量显著上升,ZT18(24:00)-ZT21(03:00)表达量降低。研究结果表明: 生物钟基因在鳜肝脏和心脏中所表达的昼夜节律不同。     

Time of symptom onset and value of myocardial blush and infarct size on prognosis in patients with ST-elevation myocardial infarction

In patients with ST-segment elevation myocardial infarction (STEMI), the time of onset of ischemia has been associated with myocardial infarction (MI) size. Myocardial blush grade (MBG) reflects myocardial response to ischemia/reperfusion injury, which may differ according to time of the day. The aim of our study was to explore the 24-hour variation in MBG and MI size in relation to outcomes in STEMI patients. A retrospective multicenter analysis of 6970 STEMI patients was performed. Time of onset of STEMI was divided into four 6-hour periods. STEMI patients have a significant 24-hour pattern in onset of symptoms, with peak onset around 09:00 hour. Ischemic time was longest and MI size, estimated by peak creatine kinase concentration, was largest in patients with STEMI onset between 00:00 and 06:00 hours. Both MBG and MI size were independently associated with mortality. Time of onset of STEMI was not independently associated with mortality when corrected for baseline and procedural factors. Interestingly, patients presenting with low MBG between 00:00 and 06:00 hours had a better prognosis compared to other groups. In conclusion, patients with symptom onset between 00:00 and 06:00 hours have longer ischemic time and consequently larger MI size. However, this does not translate into a higher mortality in this group. In addition, patients with failed reperfusion presenting in the early morning hours have better prognosis, suggesting a 24-hour pattern in myocardial protection.     

圈养獐春夏季昼间行为时间分配及活动节律

2008 年3 ～7 月,在上海市浦东新区华夏公园进行獐重引入试点,采用瞬时扫描取样法和全事件记录法,对圈养条件下24 只獐(12 雌,12 雄)春夏季昼间行为时间分配及活动节律进行了观察。结果表明:休息是春夏季最主要的行为方式,其次是摄食和运动。獐的昼间行为具有明显的节律性,以晨昏活动为主,主要活动时间集中在06:00 ～08:00 和16:00 ～18:00。单因素方差分析(One-way ANOVA analysis)和Mann-Whitney U 检验表明,在时间分配上,春、夏季休息、站立、排遗、梳理和运动行为差异极显著;雌雄间休息、站立、反刍、梳理和警戒行为差异极显著。雌性春、夏季站立、排遗、梳理、运动和社会行为差异极显著,摄食差异显著;雄性春、夏季休息、摄食、梳理、警戒和社会行为差异极显著,站立、反刍、排遗和运动行为差异显著。本研究结果表明重引入獐的行为时间分配和活动节律与野生种群相似,动物福利得到较好满足,对下一步在上海地区的种群复壮和迁地野放等具有重要意义。     

Locomotor activity rhythm in two wrasses,Halichoeres tenuispinnis andPteragogus flagellifera,under various light conditions

The locomotor activity rhythms were examined by using an actograph with infra-red photo-electric switches for two species of wrasses, (Halichoeres tenuispinnis andPteragogus flagellifera) under various light conditions. InH. tenuispinnis, the locomotor activity of almost all fish under light-dark cycle regimen (LD12:12; 06:00–18:00 light, 18:00–06:00 dark) commenced somewhat earlier than the beginning of light period and continued till somewhat earlier than the beginning of the dark period. This species clearly showed free-running activity rhythms under both constant illumination (LL) and constant darkness (DD). Therefore,H. tenuispinnis appeared to have a circadian rhythm. The length of the circadian period ranged from 23 hr. 30 min. to 23 hr. 44 min. under LL, and was from 23 hr. 39 min. to 24 hr. 18 min. under DD. On the other hand, the locomotor activity ofP. flagellifera occurred mostly in the light period under LD 12:12. The activity of this species continued through LL, but was greatly suppressed in DD, so that none of the fish had any activity rhythm in both constant conditions. It was known from field observations thatH. tenuispinnis burrowed and lay in sandy bottoms, whileP. flagellifera hid and rested in bases of seagrasses and shallow crevices of rocks during the night. In the present two wrasses, it seemed that the above-mentioned difference of noctural behavior was closely related to the intensity of the endogenous factor in the activity rhythm.     

Influence of Photoperiod, Daylength, and Feeding Schedule on Tadpole Growth and Development

The metamorphic rate of Rana pipiens tadpoles was studied under different photoperiods, daylengths, and feeding schedules. Tail resorption and hindlimb growth and development induced by immersion in 30 μg/l thyroxine (T₄) were accelerated under longer photoperiods and continuous light when 6L: 18D, 12L: 12D, 18L: 6D, and 24L regimes were compared. Constant light exposure did not produce faster development than an 18 hr photoperiod, and initially was less effective. The rate of spontaneous and T₄-induced metamorphosis was greater the shorter the day on 9L:9D, 12L: 12D, or 15L: 15D cycles, although all groups received the same overall amount of light, but in different dosages. When feeding schedule but not the LD cycle was varied, groups of tadpoles fed on 18, 24, or 30 hr regimes showed no differences in growth and development rate on 19L: 5D, and only random variations under continuous light. Differences in metamorphic rate on 18, 24, or 30 hr days are not due to the feeding schedules, but to the LD cycles. From these experiments we conclude that illumination, particularly the length and frequency of the photoperiod, affects the utilization of T₄. Development rates independent of the total amount of illumination, but related to daylength and light schedule, suggest interaction of light with an endogenous timing mechanism.     

Diurnal rhythms of body temperature, heart rate, and behaviour in the stanchioned adult Shiba goats

Using a data logger system, body temperature (dorsal subcutaneous temperature), heart rate, ingestive or ruminating behaviour and posture in adult Shiba goats tied to a stanchion were recorded automatically during 24 hours, to obtain basic information on the biological rhythms. A 600 g of usual ration mixed with hay cube, hay, beet pulp and wheat bran was fed twice a day (morning; 9:00-9:30, evening; 16:00-16:30). Animals kept under an artificial photoperiod (12L-12D, light period; 5:30-17:30) and about 10 degrees C room temperature. 1) Diurnal patterns of the above-mentioned items were recorded, mutual relationships relationships between these items were revealed. 2) The heart rate was higher after morning feeding, or during a light period and decreased gradually from midnight to early morning. Twice feeding greatly increased the heart rate. 3) The body temperature was lower in the early morning and increased gradually after morning feeding and showed the highest level during 1 to 1.5 hours after evening feeding. After that it decreased gradually till the early morning. 4) The numbers of jaw movement (bites/min) were a 70-90 bites in the ingestive behaviour and a 80-90 bites in the ruminating behaviour at dark period. 5) The total heart rate was a 110000 to 120000 beats/day, the total biting time was a 9.5 hours/day, and the mean standing time was a 9.3 to 11.7 hours/day. The standing time during light period (12 hours) was a 7.3 to 9.9 hours and that during dark period (12 hours) was a 1.8 to 2 hours.