Mitotic activity and cell degeneration in the mouse thymus over a period of 24 hrs

Kirk, Henrik

doi:10.1007/bf00306935

Cited by 12 publications

(4 citation statements)

References 17 publications

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“…The t, value of 10-12 hr indicates a biphasic diurnal rhythm of the mitotic activity in thymic blast cells. Other studies have shown a monophasic diurnal rhythm in mitotic index in the thymus (Kirk, 1972). The discrepancy might be due to measuring the mitotic index as the only parameter of mitotic activity.…”

Section: Discussionmentioning

confidence: 79%

Studies on the Regulation of Lymphocyte Production in the Murine Thymus and Some Effects of a Crude Thymus Extract

Olsson

Claësson

1975

Cell Proliferation

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Cell proliferation in the murine thymus was studied in vivo under normal conditions and from 0 to 24 hr after a single injection of a water‐soluble extract from mouse thymus, mouse spleen, and mouse skin. The thymus extract reduced during the first 24 hr the mitotic activity 40%; the spleen extract had a weaker inhibitory effect. The skin extract had no such effect. The thymus extract and spleen extract inhibited the flux of cells into the S phase 0–8 hr after the injection of the extract. Initial labelling index was also reduced in this period. Eight hours after injection of the thymus or spleen extracts the inhibited cells initiated DNA synthesis. The rate of progression of blast cells through the cell cycle was normal 24 hr after the injection of the extracts. It was deduced from the analysis that the thymus extract inhibits processes triggering Go/Gi cells into DNA synthesis, the inhibition of G2 efflux being of minor importance. Finally a model for the regulation of proliferating thymic blast cells and the emigration of small lymphocytes from the thymus is proposed.

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Section: Discussionmentioning

confidence: 79%

Studies on the Regulation of Lymphocyte Production in the Murine Thymus and Some Effects of a Crude Thymus Extract

Olsson

Claësson

1975

Cell Proliferation

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“…According to the zonal pattern of the thymus, the 3H-index was evaluated in a 501am wide subcapsular region (outer cortex), a 100 gm wide cortico-medullary zone (inner cortex) and in the thymus medulla (Griss et al, 1970;Kirk;1972). According to the zonal pattern of the thymus, the 3H-index was evaluated in a 501am wide subcapsular region (outer cortex), a 100 gm wide cortico-medullary zone (inner cortex) and in the thymus medulla (Griss et al, 1970;Kirk;1972).…”

Section: Methodsmentioning

confidence: 99%

DNA-synthesis in the rat thymus after focal thermolesions on abdominal organs

Grouls

Helpap

1978

Res. Exp. Med.

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The changes in the DNA-synthesis of lymphocytes in the different zones of the rat thymus were autoradiographically studied with 3H-thymidine after focal thermonecroses (740 degrees C/4 sec) on abdominal organs and sham operation (laparotomy). A single thermolesion was performed in separate groups of rats on the liver and spleen, whereas a third group received multiple heat lesions (liver, kidney, stomach wall). A slight decrease of the labeling index occured during the first 36 h after the sham operation and was attributed to an unspecific stress effect leading to an increased release of corticosterones. The most remarkable and contrasting result was the observation that after thermonecroses a decrease of the labeling index of thymus-lymphocytes did not happen during the first 48 h but rather a marked increased with a maximum on the fifth day. It was concluded that the stimulated DNA-synthesis in the thymus might be related to a cell mediated immune response against thermocoagulated tissue components or to an immediate T-cell dysfunction, which is known to develop after burns. In both cases the thymus might react with an increased division and maturation of lymphocytes regulated through a feed-back mechanism.

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“…). These early studies also showed circadian variation of specific immune cell types and their activity, for example the variation of mitotic activity and cell degeneration in the mouse thymus over a period of 24 h . Many other examples have been published since, some of which concern highly specific immune functions.…”

Section: Circadian Genes and The Immune Systemmentioning

confidence: 99%

Circadian rhythm‐related genes: implication in autoimmunity and type 1 diabetes

Lebailly

Rogner

2015

Diabetes Obesity Metabolism

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Recent gene association and functional studies have proven the implication of several circadian rhythm-related genes in diabetes. Diabetes has been related to variation in central circadian regulation and peripheral oscillation. Different transcriptional regulators have been identified. Circadian genes are clearly implicated in metabolic pathways, pancreatic function and in type 2 diabetes. Much less evidence has been shown for the link between circadian regulation and type 1 diabetes. The hypothesis that circadian genes are involved in type 1 diabetes is reinforced by findings that the immune system undergoes circadian variation and that several autoimmune diseases are associated with circadian genes. Recent findings in the non-obese diabetic mouse model pinpoint to specific mechanisms controlling type 1 diabetes by the clock-related gene Arntl2 in the immune system. Keywords: circadian rhythm, cytokine, immune system, transcription factor, type 1 diabetes Date submitted 10 April 2015; date of final acceptance 5 May 2015 Circadian Genes and DiabetesThere is growing evidence about the implication of the circadian rhythm in diabetes development [1]. Studies in mice have shown that the disruption of circadian rhythms can accelerate diabetes and -cell loss [2]. In humans a link between the central circadian rhythm regulation and glucose homeostasis has been suggested by findings such as the polymorphism in MTNR1B, encoding the melatonin receptor 1B, that increases the risk for type 2 diabetes [3].Transcription and translation of core clock components circadian locomotor output cycles kaput (CLOCK), aryl hydrocarbon receptor nuclear translocator-like 1 (ARNTL1), aryl hydrocarbon receptor nuclear translocator-like 2 (ARNTL2), period circadian proteins (PER1, PER2, PER3) and Cryptochromes (CRY1 and CRY2) play a pivotal role in rhythm generation in the suprachiasmatic nucleus, which is the site of the master circadian oscillator in mammals, but also in the control of peripheral oscillations.The direct relation of CLOCK-related genes in diabetes has already been shown [4]. ARNTL1, which is also called brain and muscle ARNT-like 1 (BMAL1) or member of PAS superfamily 3 (MOP3), has been genetically linked to hypertension and type 2 diabetes in humans [5]. Knockout mice for Arntl1 and Clock exhibited a role for the -cell clock in coordinating insulin secretion with the sleep-wake cycle, and revealed that ablation of the pancreatic clock can trigger the onset of diabetes mellitus [6]. The major circadian pacemaker ARNTL1 has in addition been associated with susceptibility to gestational diabetes mellitus [7]. CRY, another component of the core clock, is required for the regulation of inflammatory cytokines via the NF-kappaB Other homologous genes of the family of basic helix-loophelix transcription factors, such as the dioxin-receptor encoding gene AHR [10], ARNT [11] have been associated with diabetes. The Aryl Hydrocarbon Receptor (AHR) is a cytosolic transcription factor that is normally inactive, bound to several co-cha...

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Mitotic activity and cell degeneration in the mouse thymus over a period of 24 hrs

Cited by 12 publications

References 17 publications

Studies on the Regulation of Lymphocyte Production in the Murine Thymus and Some Effects of a Crude Thymus Extract

Studies on the Regulation of Lymphocyte Production in the Murine Thymus and Some Effects of a Crude Thymus Extract

DNA-synthesis in the rat thymus after focal thermolesions on abdominal organs

Circadian rhythm‐related genes: implication in autoimmunity and type 1 diabetes

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