摘要:

In accordance with earlier investigations of other authors, some diseases of the oral mucosa occur predominantly at appointed seasons of the year. Aphthous ulcers, Herpes labialis simplex, Actinomycosis cervico‐facialis and Erythema exsudativum multiforme show peaks of frequency in March/April and August/September/October, while acute necrotizing ulcerative gingivitis has a large peak of frequency in winter time.

ISSN:0022-1945    

DOI:10.1080/09291018209359784

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A24 h (12h on: 12h off) cycle in a weak 10 Hz electric field was imposed onDrosophilahoused in constant conditions. A 6 h phase advance in this cycle perturbed the recorded locomotor activity rhythm.

ISSN:0022-1945    

DOI:10.1080/09291018209359785

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Dynamic relations between the circulating estrogen and the hypophyseal gonadotropin secretion in the estrous cycle were investigated by replacing the ovaries by an infusion pump in freely moving rats. Female rats were ovariectomized in the morning at certain stages of the 4‐day estrous cycle, and simultaneously infused with estradiol (E2) at a constant rate of 0.35 ng/min up to 120 h through a cannula chronically inserted into the jugular vein. They were killed at 6 h‐intervals. Rats ovariectomized at the second day of diestrus and at estrus showed a sharp rise in LH 36 h and 84 h, respectively, after the initiation of E2infusion, when the proestrous surge would occur in normal rats. During the other periods, blood levels of LH were very low, exhibiting a small daily rise in the evening. Similarly ovariectomized rats infused with vehicle only showed a gradual rise of gonadotropin secretion, never reaching the surge level. Rats ovariectomized at proestrus and infused with E2showed a LH surge 12 h later as expected. However, surge‐like LH secretions followed every evening thereafter. Thus, the constant supply of E2alone could simulate at least one 4‐day cyclic LH surge in ovariectomized rats. E2infusion caused a daily peak of FSH synchronized with the LH rises, but could not suppress the post‐operative hypersecretion. It is discussed that if the suppressing effect of progesterone endogenously secreted from the ovaries is cleared, a circadian pattern of the LH/FSH surge may appear under the signal from the cerebral clock mechanism and the effect of circulating estrogen. The failure to suppress the FSH hypersecretion by E2might indicate the involvement of inhibin in the regulatory mechanism. Time‐course changes in uterine and vaginal weights are also dealt with and discussed in relation to the constant E2exposure.

ISSN:0022-1945    

DOI:10.1080/09291018209359786

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

For the first time evidence has been provided for a circannual gonadal cycle in any avian species (male spotted muniaLonchura punctulata, Estrildidae) held on continuous light. A model has thus been rendered available in which the “entraining effects” of photoperiod could be clearly distinguished from its direct “driving effects”.

ISSN:0022-1945    

DOI:10.1080/09291018209359787

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The circadian change of the encephalic photosensitivity of quail has been demonstrated. In this study the diurnal variation of the retinal photosensitivity was investigated by the electroretinogram (ERG) to explore the phase relation between the retinal and encephalic systems. The b‐wave, a major component of the ERG, was used as a measure of retinal photosensitivity.1.In the bird maintained in LD12:12 the b‐wave amplitude of the ERG stayed at a high level for the first 10 h of the light period, and decreased abruptly around the time of light‐off. The decreased level continued until midnight. Thenceforth the b‐wave amplitude recovered progressively to the daytime level before the time of next light on.2.In the bird maintained in LD16:8, the decrease of the retinal sensitivity in the light phase was initiated prior to the time of expected light‐off, and the onset time of decreasing tendency was advanced by 2 h, with dark adaptation for 30 min given immediately before the ERG measurement. Upon continuous light exposure, the b‐wave amplitude always remained at low level.3.Periodic changes in retinal sensitivity persisted when the environmental dark phase was temporarily extended for 19 to 30 h.

ISSN:0022-1945    

DOI:10.1080/09291018209359788

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Tetrahymena pyriformissyngen 1 was kept in the ultradian growth mode and synchronized by a sequence of 4‐h 20°C/l‐h 0°C cycles. Upon transfer to constant 20°C, the cells showed a free‐running ca. 5‐h rhythm of tyrosine aminotransferase activity. This rhythmicity persisted after treatment with cycloheximide applied in concentrations leading to inhibition of cell growth. These data suggest the existence of an ultradian oscillator, which seems to be independent or to be at least not the consequence of the cell cycle, but which might be related to the rhythmicity of cell division in normal conditions.

ISSN:0022-1945    

DOI:10.1080/09291018209359789

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Polysomal messenger RNA from rat liver microsomal fractions was translated in a hepatic invitrosystem containing among other components Sephadex G‐25 eluate.3H leucine incorporation was measured both in overall protein and in integral membrane proteins prepared from microsomal membranes by treatment with EDTA and 2M LiCl. In the first series of experiments, microsomes from different phases of the diurnal cycle were incubated for protein synthesis with the same G‐25 eluate from a single time of day. The rates of protein synthesis revealed a diurnal rhythmicity with major maximum at 300h. In the second series, two microsomal fractions from different diurnal phases were pre‐incubated with their own post‐microsomal supernatant and with that from another time of day. The incubation of the re‐isolated microsomes was carried out with two G‐25 eluates from different phases. These experiments indicated the existence of a diurnally fluctuating cytosolic factor or factors controlling protein synthesis. The existence of such a factor was confirmed by a third series of experiments: microsomal preparations from a single time of day were incubated with Sephadex G‐25 eluates from various phases. The degree of stimulation of overall and membrane protein synthesis exerted by the eluates was found to change rhythmically.

ISSN:0022-1945    

DOI:10.1080/09291018209359790

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A functional model‐equation is used to predict a forty‐year limit cycle behavior in the spruce budworm‐forest ecosystem. The prediction agrees well with the available, albeit scarce data in the literature.

ISSN:0022-1945    

DOI:10.1080/09291018209359791

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018209359792

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

ISSN:0022-1945    

DOI:10.1080/09291018209359783

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor