Developmental characteristics in the daily rhythm of norepinephrine concentration within rabbit brainstem regions

1996 ◽  
Vol 8 (1) ◽  
pp. 189 ◽  
Author(s):  
JL Gingras ◽  
EE Lawson ◽  
MC McNamara
Keyword(s):  
Daily Rhythm ◽  
Distinct Region ◽  
Developmental Patterns ◽  
The Third ◽  
Tissue Weight ◽  
Daily Variations ◽  
Radioenzymatic Assay ◽  
Norepinephrine Concentration ◽  
Developmental Characteristics

To examine the development of daily variations in norepinephrine levels, norepinephrine concentrations were measured within five distinct brainstem regions in 3-day-old, 21-day-old, and adult rabbits at 6-h intervals throughout the day. Norepinephrine was measured by radioenzymatic assay, and norepinephrine concentration was expressed relative to wet tissue weight. The data suggest that daily variations for norepinephrine concentrations are established by the third day of life. In the brainstem as a whole, there was an early nocturnal peak (2130 hours) for 3-day-old animals in contrast to a late nocturnal peak (0330 hours) for 21-day-old animals. Adult animals showed a late diurnal (1530 hours) peak. These gross daily variations constitute the sum of distinct region-specific patterns in the development of daily variations in norepinephrine concentration. Norepinephrine is involved in cardiorespiratory regulation and in the regulation of sleep/wake cycles. The observed developmental patterns may relate to the maturation and integration of these physiologic processes.

Enhancement of corticosterone release by repeated injections of ACTH in the dexamethasone pre-treated rat

1983 ◽  
Vol 102 (4) ◽  
pp. 583-588 ◽  
Author(s):  
Noboru Murakami ◽  
Kiyohisa Takahashi
Keyword(s):  
Body Weight ◽  
Adrenal Gland ◽  
Adrenocorticotrophic Hormone ◽  
Blood Samples ◽  
Pulsatile Secretion ◽  
The Third ◽  
Daily Variations ◽  
Corticosterone Response ◽  
Corticosterone Release ◽  
Adrenal Corticosterone

Abstract. To examine the possibility that pulsatile secretion of adrenocorticotrophic hormone (ACTH) enhances the responsiveness of the adrenal, the blood corticosterone response to repeated injections of ACTH was determined in the dexamethasone-nembutal pre-treated rat. Treatment with dexamethasone (100 μg/100 g body weight) at 13.00 h for 2 days decreased corticosterone levels and completely abolished these daily variations in both the blood and adrenal. Under these conditions, four or five successive iv injections of 0.2 or 2 mIU ACTH were given at ½ or 1 h intervals. Blood samples were taken immediately before and at frequent intervals after injection. A significant increase of blood corticosterone levels was observed 10 min after the second injection of 0.2 mIU ACTH. Further increases in blood corticosterone levels were observed after the subsequent injections. In addition, repeated injections of 2 mIU ACTH augmented the responsiveness of the adrenal to ACTH. The second or the third injections of 2 mIU ACTH produced a greater increase in adrenal corticosterone content than did the first ACTH injection. These results suggest that when ACTH acts on the adrenal gland in a pulsatile fashion, the steroidogenic response of the adrenal to ACTH increases markedly.

Early seed development in Triticum-Secale amphiploids

1985 ◽  
Vol 27 (5) ◽  
pp. 542-548 ◽  
Author(s):  
J. P. Gustafson ◽  
A. J. Lukaszewski
Keyword(s):  
Seed Development ◽  
Interspecific Hybrid ◽  
Triticum Durum ◽  
Early Embryo ◽  
Hybrid Wheat ◽  
Developmental Patterns ◽  
Wheat Embryo ◽  
Telomeric Heterochromatin ◽  
Early Seed Development ◽  
Developmental Characteristics

Considerable variation was observed in the early embryo and endosperm developmental patterns of several Triticum durum × Secale species (africanum, cereale, dighoricum, kuprijanovii, montanum, segetale, vavilovii) amphiploids. However, the Triticum – S. africanum hybrid was the only one which developed at a faster rate than either of its parents. Its endosperm became cellular and began depositing starch at least 24 h before any previously analyzed cereal. The influence of Secale DNA and heterochromatin on the developmental patterns of the amphiploids was exactly the opposite of that in the genus Secale itself (i.e., as the amount of telomeric heterochromatin increases developmental speed decreases). The results, in general, suggest that the control of Secale developmental characteristics, whether they are genotypic or nucleotypic, are suppressed when placed in a wheat background.Key words: triticale, heterochromatin, interspecific hybrid, wheat embryo.

Redial generations ofFasciola hepatica: a review

2009 ◽  
Vol 83 (3) ◽  
pp. 245-254 ◽  
Author(s):  
D. Rondelaud ◽  
M. Belfaiza ◽  
P. Vignoles ◽  
M. Moncef ◽  
G. Dreyfuss
Keyword(s):  
First Generation ◽  
Second Generation ◽  
Fasciola Hepatica ◽  
Abnormal Development ◽  
Third Generation ◽  
Biotic Factors ◽  
Snail Infection ◽  
Developmental Patterns ◽  
The Third

AbstractAn update on the redial generations ofFasciola hepaticawas carried out to highlight the different developmental patterns of rediae, the effects of some factors on these generations, and the consequences of such developmental patterns on cercarial productivity. The development of generations is dependent on the behaviour of the first mother redia of the first generation. If this redia remains alive throughout snail infection, it produces most second-generation rediae. In contrast, if it dies during the first weeks, daughter redia formation is ensured by a substitute redia (the second mother redia of the first generation, or the first redia of the second generation). Environmental and biotic factors do not modify the succession of redial generations, but most act by limiting the numbers of rediae, either in all generations, or in the second and/or third generations. An abnormal development of rediae reduces the number of cercariae and most are formed by the second cohort of the first generation. By contrast, most cercariae are produced by the first cohort of the second generation when redial development is normal. The mother rediae described by previous authors might correspond to the first generation and the second cohort of the second generation, while daughter rediae would be the second cohort of the second generation and the first cohort of the third generation. Under certain circumstances, daughter redia formation is ensured by the first two mother rediae or all first-generation rediae, thus demonstrating that the first mother redia is not the only larva to ensure daughter redia formation.

Developmental characteristics of grass varieties in relation to their herbage production: 3. Tiller development in Dactylis glomerata and Loliutn perenne in relation to head emergence

1978 ◽  
Vol 91 (1) ◽  
pp. 117-129 ◽  
Author(s):  
I. Davies
Keyword(s):  
Vertical Distribution ◽  
Lolium Perenne ◽  
Perennial Ryegrass ◽  
Environmental Effects ◽  
Species Differences ◽  
Dactylis Glomerata ◽  
Extension Growth ◽  
Developmental Patterns ◽  
Developmental Characteristics ◽  
The Vertical Distribution

SummaryFeatures of the gross morphology of primary growth of Dactylis glomerata and Lolium perenne, and associated changes in digestibility are described.Species differences were noted with regard to the relationships between head emergence and the time when stem apices were raised to defoliation height, vegetative/ reproductive tiller ratios, and tiller size.Also there were differences in the sequence of extension growth of leaf sheaths, internodes and inflorescence leading to emergence of the head. Associated changes in the vertical distribution of leaf blades were examined.In perennial ryegrass extension growth of the inflorescence continued after emergence had begun, but not in cocksfoot. Weight increments in the inflorescence, from emergence onward, followed the same pattern in the two species, however.Differences in the developmental patterns of the two grasses did not appear to influence their relative digestibility.Upper internodes of reproductive tillers of S. 24 ryegrass declined rapidly in digestibility Species differences, and the pattern of changes in the digestibility of lower and upper parts of reproductive tillers are discussed in relation to mechanical aspects of sward development and micro-environmental effects.

scholarly journals The Acquisition of Requests in the Speech of Lithuanian Children

2016 ◽  
pp. 160-187
Author(s):  
Viktorija Kavaliauskaitė
Keyword(s):  
Communicative Competence ◽  
Future Tense ◽  
Developmental Patterns ◽  
The Third ◽  
Illocutionary Acts ◽  
Different Types ◽  
Modal Verb ◽  
Indirect Requests ◽  
Second Year ◽  
Children's Speech

This work focuses on early development of requests and investigates how and when these illocutionary acts are acquired by Lithuanian children. There are various ways to ask someone to do something. Expression of requests can vary according to the degree of directness depending on social context. These requests indicate communicative competence, development of pragmatics and politeness rules. The key aim of this study was to investigate types of requests and the sequence of those types first emerging in child speech.The study was based on the longitudinal data of two Lithuanian children, a girl Monika, aged 1;8–2;8, and a boy Elvijus, aged 1;6–2;7. The requests were also analyzed in child directed speech. According to the degree of directness and different types of requests, they were classified into direct (explicit performatives, imperatives, want / obligation statements, prohibitions), conventionally indirect (references to preconditions, hortatives) and non-conventionally indirect requests (hints, warnings).The results of the study demonstrate that direct requests were acquired first and they were the most common in children’s speech and in child directed speech. Firstly, the children formulate requests with nouns, the adverb more, verbs in 2SG imperative, the infinitive and hortative in 1PL present tense, they also use the modal verb want. Later, requests with nouns, infinitive and future tense disappear, the children’s requests start to resemble child directed requests. It was noticed that at the end of the second year the children started using formal and indirect requests. At the beginning of the third year, they acquire the basics how to formulate requests. Presumably, other Lithuanian children could demonstrate similar developmental patterns.

scholarly journals The Behaviour of Minnows in Relation to Light Intensity

1956 ◽  
Vol 33 (2) ◽  
pp. 271-281
Author(s):  
F. R. HARDEN JONES
Keyword(s):  
Light Intensity ◽  
Bright Light ◽  
Daily Rhythm ◽  
Locomotory Activity ◽  
Natural Conditions ◽  
Daily Variations ◽  
Light Side ◽  
Hollow Bricks

1. Minnows kept in a tank are active during the day and quiet at night. Their behaviour is reversed if they are given hollow bricks in which they take cover and so avoid bright light. When cover is available they are very active at sunrise and sunset. 2. Minnows have no inherent daily rhythm of locomotory activity. 3. Blind minnows respond to daily variations in light intensity, and are more active at night than during the day. 4. Minnows will not cross a light-dark boundary when the intensity on the light side is greater than 0.17-0.08 m.c 5. A minnow shoal disperses between intensities of 0.024 and 0.0034 m.c. 6. Minnows catch Dapknia better in bright light than in the dark. The change from visual to ‘dark’ feeding takes place between 0.0007 and 0.00007 m.c. 7. Minnows appear to avoid bright light by a comparison of intensities if the light-dark boundary is sharp, but they may also respond to light photokinetically. 8. It should be noted that these results, obtained in the laboratory, may not be true for minnows under natural conditions.

scholarly journals Daily Variations in Type II Iodothyronine Deiodinase Activity in the Rat Brain as Controlled by the Biological Clock

Endocrinology ◽  
2005 ◽  
Vol 146 (3) ◽  
pp. 1418-1427 ◽  
Author(s):  
Andries Kalsbeek ◽  
Ruud M. Buijs ◽  
Rosalinde van Schaik ◽  
Ellen Kaptein ◽  
Theo J. Visser ◽  
...  
Keyword(s):  
Biological Clock ◽  
Plasma Corticosterone ◽  
Daily Rhythm ◽  
Type Ii ◽  
Iodothyronine Deiodinase ◽  
Daily Variations ◽  
Pituitary Thyroid Axis ◽  
Thyroid Axis ◽  
The Central Nervous System

Type II deiodinase (D2) plays a key role in regulating thyroid hormone-dependent processes in, among others, the central nervous system (CNS) by accelerating the intracellular conversion of T4 into active T3. Just like the well-known daily rhythm of the hormones of the hypothalamo-pituitary-thyroid axis, D2 activity also appears to show daily variations. However, the mechanisms involved in generating these daily variations, especially in the CNS, are not known. Therefore, we decided to investigate the role the master biological clock, located in the hypothalamus, plays with respect to D2 activity in the rat CNS as well as the role of one of its main hormonal outputs, i.e. plasma corticosterone. D2 activity showed a significant daily rhythm in the pineal and pituitary gland as well as hypothalamic and cortical brain tissue, albeit with a different timing of its acrophase in the different tissues. Ablation of the biological clock abolished the daily variations of D2 activity in all four tissues studied. The main effect of the knockout of the suprachiasmatic nuclei (SCN) was a reduction of nocturnal peak levels in D2 activity. Moreover, contrary to previous observations in SCN-intact animals, in SCN-lesioned animals, the decreased levels of D2 activity are accompanied by decreased plasma levels of the thyroid hormones, suggesting that the SCN separately stimulates D2 activity as well as the hypothalamo-pituitary-thyroid axis.

The pattern of early cleavage of the marsupial frog Gastrotheca riobambae

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 781-789 ◽  
Author(s):  
E.M. del Pino ◽  
S. Loor-Vela
Keyword(s):  
Cell Shape ◽  
Slow Rate ◽  
Early Stage ◽  
Tight Coupling ◽  
Early Cleavage ◽  
Cell Stage ◽  
Midblastula Transition ◽  
Developmental Patterns ◽  
Cleavage Cycle ◽  
The Third

Comparison of early development of the marsupial frog Gastrotheca riobambae with Xenopus laevis suggests that the cleavage pattern of Xenopus and the tight coupling of events at the midblastula transition are features of the accelerated development of small amphibian eggs with aquatic reproduction, rather than generalized features of amphibian development. The large eggs of the marsupial frog Gastrotheca riobambae not only display an atypical holoblastic pattern of cleavage and a very slow rate of development, but the events of the midblastula transition are uncoupled, suggesting that amphibians may have a diversity of developmental patterns. Early cleavage of the egg, which measures about 3 mm in diameter, occurs mostly by meridional and vertical furrows. The first cleavage cycle takes about 16 to 20 h and about four days may be required to reach the midblastula stage. Cleavage becomes asynchronous at about the third cleavage cycle evidenced by the formation of cleavage furrows. However, during cleavage (up to 342-cells), the majority of the nuclei divide synchronously and only 15 to 40% of the nuclei of a given embryo have a different cleavage schedule. At the 8-cell stage, nucleoli become visible (approximately 24 h after amplexus), signaling that transcription of rRNA has started at this early stage. Cell motility was detected in three- to four-day old embryos and seems to be associated with changes in cell shape and with expansion of the blastocoel at this stage.

scholarly journals Politeness Speech Acts in the Speech of Children: Pragmatic Mistakes and Acquisition

2019 ◽  
pp. 97-124
Author(s):  
Viktorija Kavaliauskaitė-Vilkinienė
Keyword(s):  
Speech Acts ◽  
Communicative Competence ◽  
Appropriate Use ◽  
Developmental Patterns ◽  
The Third ◽  
Early Acquisition ◽  
Children's Speech

The paper aims to discuss the expression and development of politeness speech acts, i.e. greeting, saying goodbye, thanking, usage of the word please, apology, congratulation and wishes,  in the speech of a Lithuanian boy, aged 1;6–2;7, and a girl, aged 1;8–2;8. The source of data contains two corpora of transcribed conversations of the children mostly interacting with their mothers (about 20 and 27 hours of recordings are transcribed). The corpora are developed by scholars of Vytautas Magnus University, Lithuania. One of the foci of analysis is to discuss the expression and development of the above-mentioned politeness speech acts and common pragmatic errors regarding the usage of politeness formulas in the children’s speech. Another focus is the investigation of the socialization strategies applied by the parents. Based on the current research by different scholars, the article raises the hypothesis that Lithuanian children in the second or third year of life acquire the majority of politeness speech acts as discussed in this paper. The analysis revealed that at the beginning of the observation children lacked communicative competence to use politeness speech acts in a pragmatically appropriate way. They confused situations when to use politeness formulas of thanking, apology and the word please and lacked the knowledge of how to use politeness adjacency pairs. The study also shows that the repetition of parents’ politeness formulas was common. Furthermore, the appropriate use of spontaneous and pragmatic greeting and saying goodbye was observed first, and only later the usage of thanking and the word please appeared.  However, only few examples of other politeness speech acts (i.e. apology, congratulation and wishes) were observed in the corpus. Therefore, further research is necessary. The results demonstrate that at the beginning of the third year the children used most of the politeness speech acts appropriately. An early acquisition was affected by children’s familiarisation with politeness routines taught by their parents. The parents directed and prompted their children to repeat politeness formulas, elicited them by questions or performatives and sometimes taught children to be polite by producing metalinguistic comments. Current research seems to indicate that other Lithuanian children could demonstrate similar developmental patterns of politeness speech acts and make similar pragmatic errors as well as being similarly socialized to use politeness formulas.

Three Generations of Comparative Sociologies

2010 ◽  
Vol 51 (3) ◽  
pp. 363-399 ◽  
Author(s):  
Saïd Amir Arjomand
Keyword(s):  
Social Theory ◽  
Nation State ◽  
Third Generation ◽  
Historical Experience ◽  
Developmental Patterns ◽  
Comparative Sociology ◽  
Alternative Modernities ◽  
Multiple Modernities ◽  
The Third ◽  
Three Generations

AbstractSurveying three generations of comparative sociologists, separated by abrupt discontinuities, the study reaches the conclusion that the original promise of comparative sociology set in motion a century ago remains largely unfulfilled. It will then be argued that the work of the third generation of comparative sociologists on civilizational analysis and multiple modernities can redeem the promise of comparative sociology by rectifying the neglect of developmental patterns in other civilizations and recovering the fundamental relevance of the periphery. The third generation is thus seeking to undo the erasure of the historical experience of a very sizeable portion of humankind from the foundation of social theory. This argument is illustrated by selective reference to the concept of the nation-state, and comparisons of civilizational processes and developmental patterns that stem from different religions and traditions and generate varieties of nationalism, alternative modernities and patterns of secularization.

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