Circadian rythm

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The naked mole rat (Heterocephalus glaber) is a strictly subterranean, extraordinarily long-lived eusocial mammal. Although it is the size of a mouse, its maximum lifespan exceeds 30 years, making this animal the longest-living rodent. Naked mole rats show negligible senescence, no age-related increase in mortality, and high fecundity until death. In addition to delayed ageing, they are resistant to both spontaneous cancer and experimentally induced tumorigenesis. Naked mole rats pose a challenge to the theories that link ageing, cancer and redox homeostasis...

Arylalkylamine N-acetyl transferase (serotonin N-acetyl transferase, AANAT) is a critical enzyme in the light-mediated regulation of melatonin production and circadian rythm. With the objective of discovering new chemical entities with inhibitory potencies against AANAT, a medium-throughput screening campaign was performed on a chemolibrary. We found a class of molecules based on a 2,2'-bithienyl scaffold, and compound 1 emerged as a first hit. Herein, we describe our progress from hit discovery and to optimization of this new class of compounds...

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In pharmacokinetics, it is currently assumed that blood and interstitial spaces belong to the central compartment, when the solute is quickly equilibrated between both fluids. Taking into account that the same extracellular fluid dissolves the drug either in the plasma or in the interstitium, both drug concentrations (intra and intravascular) should be identical. However, this equality may not exist when there is a dissimilar distribution of blood flow among the organs. A closed, two-zone, three-compartment model was mathematically investigated...

Recent progress in the human genome project allows us to study the genetic basis of complex traits such as atherosclerosis and diabetes. Among various approaches, a genetic approach such as affected sib-paired analysis and case-control study has successfully identified genes for susceptibility to Alzheimer's disease and diabetes. Several points to be considered are discussed for their successful application to athroscelorosis. In addition, functional genomic approaches based on powerful technology such as cDNA microarray and knockout mice allow us to identify genes and proteins involved in the complex biological (disease) process...

OBJECTIVE: Transsphenoidal surgery results in biochemical remission of acromegaly in 45-80% of patients; however, few studies have addressed the impact of transsphenoidal surgery on cardiovascular function in acromegalic patients. The aim of this prospective study was to investigate the effects of postoperative GH/IGF-I normalization on echocardiographic parameters and blood pressure (BP) in a series of patients with active acromegaly. DESIGN: An open prospective study...

A group of 22 young subjects staying in rest was studied in the aim to follow the nycthemeral evolution of the rectal temperature, according to two situations: 1) normal feeding, 2) absence of feeding. The use of drinking water was not limited. The experimentation was carried out in tropical area, Kédougou (Eastern Senegal), during a high period of temperature. The mean of day temperature was 38 degrees C and the night temperature, 22 degrees C. The skin and rectal temperature, the arterial pressure and the cardiac frequency were measured every three hours...

Basal concentration was measured of prolactin (PRL) as were its diurnal fluctuations in blood depending on the clinical association of primary hypothyrosis (PH) with lactorrhea-amenorrhea, lactorrhea only or lactorrhea associated with disturbances in menstrual and reproductive functions that differ from those in amenorrhea, and without such disturbances. Patients with lactorrhea-amenorrhea syndrome present with continual hyperprolactinemia and no physiological diurnal rythm of PRL secretion. In patients presenting without amenorrhea, and basal hyperprolactinemia, lactorrhea and disordered menses result from transitory "night-time" hyperprolactinemia...

In Alzheimer's disease, when the breakdown of the sleep's circadian rythm is sudden, it reflects frequently a concomitant somatic or psychiatric disorder. If the trouble appears progressively, there is less pathological or disturbing behaviors in the beginning. Later, it is often associated with a loss of interest for the daily living activities (perte de motivation).

The evoked expression of the immediate-early gene-encoded proteins c-Fos and Krox-24 was used to study activation of mesodiencephalic structures as a function of the development of cyclophosphamide (CP) cystitis in behaving rats. This article is the third of a series and completes previously published data obtained at both spinal and hindbrain levels. CP-injected animals received a single dose of 100 mg/kg i.p. under transient volatile anesthesia and survived for 1-4 h in order to cover the entire postinjection period during which the disease develops...

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A computer simulation model of cell kinetics is established to represent the variations of rat hepatocyte populations in several circumstances: normal growth, circadian rythms, response to partial hepatectomy under different conditions. This model differs from usual mathematical models-sets of equations--by the use of digital simulation techniques. Each cell in the population is represented by a set of variables in the computer memory. When experiments are simulated, the values of these variables are modified step by step according to the hypotheses we want to test...

The interaction of daily motor activity rythm within daily changes of early transient neurological disorders (ENTD) symptoms has been evaluated. The highest frequency of five ENTD symptoms was mainly observed in that daily periods when behavior reactions were minimal. A difference was distinguished in circadian radiosensitivity of some behavior reactions in "open field" (gamma-irradiation 60Co, 62.5 Gy). The most radiosensitive ENTD symptoms were "vertical set", "immobility" and "motion on the spot", characterized emotional state and orienting-locomotor animal reactions...

Both circadian and infradian rythms in Affective State (AS) are reported in 12 subjects (10 with Affective Disorders, 2 without Mental Disorder). The segmented visual scale ESTA-III was used, which yields scores for two dimensions: Mood and Drive. Self-assessment of AS was carried out every 8 hours for about a month. The statistical procedure is underlined. Theoretical implications of findings are discussed.

No significant difference was found between the mean plasma cortisol levels in 2 groups of diabetic patients (10 with non-severe metabolic decompensation and 10 well compensated). Likewise, there was not statistical difference on considering the diurnal Cortisol/nocturnal Cortisol quotients in both groups; these quotients besides showed the persistence of the circadian rythm. No valuable difference was seen in the adrenal response to ACTH stimulus. It was found direct correlation between glycemic levels and cortisol increments after stimulus in the total series of 20 patients (r = 0...

Disease activity in rheumatoid arthritis as measured by repeated estimation of joint pain, stiffness, articular index, and grip strength was shown to have a circadian rythm, maximal activity being seen between 0200 and 0400 and minimal activity in the early afternoon. This variation in disease activity may be related to circadian alterations in immune and inflammatory responses (such as immune complexes and neutrophil function) dependent on alterations in circulating concentrations of steroids. The circadian variation in disease activity has important implications in assessment of patients, prescription of drugs, and performance of drug trials...

Serum and urinary glucose, creatinine, calcium and phosphorus, serum insulin were measured every 60 min from 9.00 to 12.00 in twenty healthy subjects. All subjects presented normal body weight, renal function, serum glucose, serum and urinary calcium. Urinary calcium and phosphorus were expressed by Ca/creat and P/creat ratio, and renal phosphate threshold was expressed by the TmP/GFR ratio. At 9.00, after an overnight fast, ten subjects received 75 g of glucose (groupe B) and ten subjects were conserved as controls (group A)...

No abstract text is available yet for this article.

No abstract text is available yet for this article.