International journal of chronobiology最新文献

{"title":"Regional variability in circadian rhythmicity of intestinal digestive-absorptive functions.","authors":"N R Stevenson,&nbsp;H S Sitren","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The circadian rhythms of sucrase, maltase, isomaltase, trehalase, lactase, gamma-glutamyltransferase, leucylnaphthylamide hydrolyzing activity, alkaline phosphatase and monosaccharide transport were assessed in each fifth of the small intestine of the rat in order to determine if an entire enzyme or transport system population responded in a similar manner or if there were regional differences. Animals were maintained under a light-dark cycle and fed from 1400-1800, EST for 7 days. Functional activities were assessed every 4 h for 24 h, inclusively. Quantitative, and in a few instances, qualitative differences in different areas of the intestine were found for all functions. There were portions of the lactase and alkaline phosphatase populations which displayed no rhythmicity in activity. When rhythmicity was observed there were differences in the activity patterns along the intestine for all functions. Thus, the rhythm patterns obtained from homogenates of the entire small intestine are a composite of the patterns in regions of high average activity. Also, there appears to be a reasonable amount of local control of the various functions.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"6 2","pages":"119-34"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11268228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chronobiological aspects of stereotyped motor behaviour in mentally retarded children.","authors":"A Meier-Koll,&nbsp;P Pohl","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Normally developed children show many diverse patterns of behaviour. By contrast, the behaviour of severely mentally retarded children is restricted mainly to primitive motor acts called stereotypes. Due to the severity of the mental retardation, these children are also markedly reduced in their susceptibility to environmental influences. Systematic observations of the pathological motor patterns of these children make it feasible to investigate possible endogenous mechanisms related to these primitive motor activities. The stereotyped motor behaviours of six severely mentally handicapped children were observed continuously for several days. Each child performed at least two forms of stereotyped behaviour. Using spectra of variance and cross-correlation analysis, the data were investigated with respect to underlying periodicities. A 2.5-hour cycle was consistently found in every stereotyped activity observed. Furthermore, stable phase relationships were revealed between the periodic variations of different stereotyped movements in one and the same child. Thus the temporal courses of hand and oral stereotypes were synchronous, whereas head and whole-body stereotypes were delayed by half a phase with respect to stereotyped hand waving. A possible relationship is discussed between the 2.5-hour periodicity of stereotyped behaviour and Kleitman's \"Basic Rest Activity Cycle\".</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"6 3","pages":"191-209"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11759376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A study of free-running rhythms in sheep.","authors":"W G Hunsaker,&nbsp;M S Wolynetz","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Free-running rhythms for eating, drinking, standing and walking activities were studied in two experiments with four cross-bred rams. In the first experiment the rhythms were entrained to a LD (12:12) (300:0) regimen. Following a change to continuous dim light (less than 2 lux) there was a suggestion of free-running activity for about three days in some of the variables. By the fourth day, however, the previously entrained rhythms had been damped out and were replaced by random patterns of activity in all variables. In the second experiment, two entraining agents were used: LD (12:12) (300:0) and restriction of feed to the light period only. There was again some indication of free-running activity for the first few days of continuous dim light (less than 2 lux) but by the fourth day only random patterns of activity were evident.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"6 4","pages":"219-30"},"PeriodicalIF":0.0,"publicationDate":"1979-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11759859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photoperiodic programming of diurnal changes in rabbit visual evoked potentials.","authors":"A C Bobbert,&nbsp;W H Krul,&nbsp;J Brandenburg","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Rabbits which have been exposed for several weeks to the natural cycles of daylight and darkness, or to various fixed 24 hr light-dark alternations, exhibit in constant environmental conditions large diurnal changes in the shape of the Visual Evoked Potential. These changes run a square-wave like time course and seem to reflect a similar diurnal rhythm in the sensitivity of the visual system to photic stimuli. The relation between the durations of the two phases of the rhythm can, within wide limits, be changed by variations in length of the artificial or natural photoperiod. It further appears that after exposure to continuous illumination or darkness rabbits have either a free-running V.E.P. rhythm or no such rhythm at all. The probable importance of the diurnal changes in the visual system for the occurrence of seasonal fluctuations in behaviour is discussed.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 1","pages":"327-44"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11765929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diurnal changes in the rabbit's visual evoked potential.","authors":"A C Bobbert,&nbsp;W H Krul,&nbsp;J Brandenburg","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Rabbits that have been exposed to the natural cycles of day and night exhibit marked diurnal changes in the shape of their Visual Evoked Potential in constant environmental conditions. The results of exposure to artificial 24 hr light-dark cycles strongly suggest that it is the regular alternation of daylight and darkness which acts as the synchronizing \"Zeitgeber\" for the V.E.P. rhythm which exists after exposure to the natural cycles of day and night. It would seem further that the V.E.P. changes reflect a square-wave like rhythm in the sensitivity of the visual system to photic stimuli, in which the sensitivity is much higher at night than in the day-time. The probable importance of the diurnal V.E.P. rhythm for the occurrence of daily fluctuations in behaviour is discussed.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 1","pages":"307-25"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11765928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparative aspects of circadian rhythms in homeotherms, re-entrainment after phase shifts of the zeitgeber.","authors":"H Pohl","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Re-entrainment of circadian activity of 3 avian species (Fringillidae: Fringilla coelebs, Carduelis chloris, Pyrrhula pyrrhula) and 4 mammalian species (Rodentia: Eutamias sibiricus, Funambulus pennanti, Glis glis, Mesocricetus auratus), subjected to 12:12 h light-dark (LD) cycles as zeitgeber, was studied after shifting the LD cycle by different amounts (hours) and in different directions (advances and delays). The properties of the zeitgeber were changed by varying light intensity during dark-time (ID) and/or light-time (IL). After 6 and 9-h advance and delay shifts of the LD cycle, the 3 species of finches similarly re-entrained their activity rhythms in the direction of the shifted zeitgeber. After 10.5 and 12-h shifts, the majority of individuals re-entrained by delay phase shifts of the rhythms. After two successive 6-h advance or delay shifts (resulting in inversion of the LD cycle) most finches responded by advances. Generally, the time needed for re-entrainment of 2/3 of the full shift (2/3 tr) in finches dependend on: (a) the direction of the phase shift ('asymmetry effect'), and (b) the phase-angle difference between onset of activity and light-on (psio) before the shift. After 12-h shifts, species-specific differences in the direction of re-entrainment and in the slope of the relationship between 2/3 tr and psio were found. In two rodents, the nocturnal golden hamster and the diurnal Siberian chipmunk, the direction of re-entrainment following inversion of the LD cycle depended on psio. In both species, 2/3 tr after inversion of the zeitgeber was significantly longer than in the common dormouse. In chipmunks, changes in 2/3 tr were correlated with changes in psio due to systematic variation of the zeitgeber properties (range and/or mean level). After 6-h phase shifts, the 'asymmetry effect' was opposite in the two nocturnal rodents, the hamster and the dormouse. It is suggested that the time course (direction and rate) of re-entrainment was influenced by differences in the characteristics of the circadian systems and their responses ('sensitivity') to light changes in the various species of birds and mammals.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 4","pages":"493-517"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11902224","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal fluctuations of the circadian changes in rabbit visual evoked potentials.","authors":"A C Bobbert,&nbsp;J Brandenburg,&nbsp;W H Krul","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>Two rabbits were exposed for more than a year to the natural cycles of daylight and darkness. At intervals of 2 months and less records were taken of the time course of the 24 hr rhythm appearing in constant conditions in their cortical flash-evoked responses. It appeared that the rhythm can be programmed as well by the natural light-dark alternations as by artificial cycles. In temperate zones this \"natural programming\" causes large seasonal fluctuations in the time course of the rhythm which reflects, over the major part of the year and with remarkable precision, the times of sunrise and sunset and, in consequence, the length of the day. The possible significance of fixing daylength temporarily in the nervous system is discussed in connection with Bünning's hypothesis on the causation of seasonal photoperiodism.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 4","pages":"519-32"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11902225","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Circadian variations of ovarian ascorbic acid depletion in response to luteinising hormone in the rat.","authors":"G Grizard,&nbsp;D Boucher,&nbsp;L Thieblot","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The ovarian ascorbic acid (OAA) was titrated, three hours after an I.V. injection of either saline or LH, administered to 46 day-old Sprague Dawley female rats pretreated with P.M.S., H.C.G., and estradiol benzoate (and undecylate). The rats were killed at specific times along the 24-hour scale (L.D. 12:12; L 06(00) to 18(00); Ambient temperature 24 degrees C +/- 2 degrees C). The OAA content varied with a statistically significant circadian rhythm in the controls. The minimum dose of LH effecting OAA depletion varied systematically with the circadian system phase. OAA depletion increases with the dose of LH, and also depends on the circadian time that the animal is killed; it is maximum at the same time that the OAA peak is found in the controls. The slope of the linear regression (quantity of OAA as a function of the logarithm of the LH doses administered) is always significant, but varies over the 24-hour span; in consequence the LH biological titration must be carried out rapidly, the optimal circadian time for killing the animals is about 16(30).</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 4","pages":"533-44"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11902226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On temporal structure of human hiccups: ethology and chronobiology.","authors":"T R Anthoney,&nbsp;S L Anthoney,&nbsp;D J Anthoney","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>During a study on the phylogeny and ontogeny of human hiccups, essentially all hiccups to occur over continuous periods of 3m - lly were recorded from 20 healthy people of either sex and various ages. Hiccups displayed considerable structure in time. If more than a few occurred together, they became \"established\" and a hiccup bout ensued, which did not stop until a certain \"minimum\" number of hiccups had occurred. For many subjects, two or more bouts frequently occurred on the same hiccup day, even though days on which bouts occurred were weeks apart. Number of hiccups was correlated with age, sex, reproductive status and stage of menstrual cycle, time of day, length of time since previous hiccup day, length of time since previous hiccup bout, and length of hiccup-hiccup intervals within a bout. Findings support the hypothesis that human hiccup is a \"fixed action pattern\" (FAP)--a central theoretical concept in ethology--and provide leads for further studies aimed at learning the biological function(s) of human hiccup and its possible homologues in other species.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 3","pages":"477-92"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11890619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Growth rhythms of the cartilage of the mandibular condyle: effects of orthopaedic appliances.","authors":"C Oudet,&nbsp;A Petrovic","doi":"","DOIUrl":"","url":null,"abstract":"<p><p>The growth rate of the cartilage of the mandibular condyle in the young rat exhibits: - a circadian cycle with a maximum of the 3H-thymidine labelled cells around 13(00) and a minimum around 01(00); with a maximum in the number of mitoses around 21(00) and a minimum around 09(00). - a circannual cycle with a maximum in May and a minimum between November and January, and with a difference in rhythms between May and November. The condylar cartilage growth in response to orthopaedical appliances of the mandible is modified and exhibits: - circadian variations. - circannual variations. The responsiveness of the condylar cartilage to orthopaedic appliances is greater when the condylar cartilage growth rate is higher.</p>","PeriodicalId":75936,"journal":{"name":"International journal of chronobiology","volume":"5 4","pages":"545-64"},"PeriodicalIF":0.0,"publicationDate":"1978-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"11902227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}