The Review of Current Knowledge on Neutrophil Gelatinase-Associated Lipocalin (NGAL).

Neutrophil gelatinase-associated lipocalin (NGAL) is a 25-kDa protein that is secreted mostly by immune cells such as neutrophils, macrophages, and dendritic cells. Its production is stimulated in response to inflammation. The concentrations of NGAL can be measured in plasma, urine, and biological fluids such as peritoneal effluent.

Melatonin Treatment in Kidney Diseases.

Melatonin is a neurohormone that is mainly secreted by the pineal gland. It coordinates the work of the superior biological clock and consequently affects many processes in the human body. Disorders of the waking and sleeping period result in nervous system imbalance and generate metabolic and endocrine derangements.

Changes of the clock gene expression in central and peripheral organs of common carp exposed to constant lighting conditions.

In both mammals and fish, the circadian system is composed of oscillators that function at the cellular, tissue, and system levels and show the cyclic expression of clock genes. The organization and functioning of the biological clock in fish has not yet been characterized in detail, therefore, in the present study, an extensive analysis of the rhythmic expression of the main components of the biological clock in the central and peripheral organs of common carp was performed. The diurnal changes in clock gene expression were determined with respect to the subjective light cycle in fish exposed to constant light or darkness.

Corrigendum: Modeling Bilingual Lexical Processing Through Code-Switching Speech: A Network Science Approach.

[This corrects the article DOI: 10.3389/fpsyg.2021.

Modeling Bilingual Lexical Processing Through Code-Switching Speech: A Network Science Approach.

The study of code-switching (CS) speech has produced a wealth of knowledge in the understanding of bilingual language processing and representation. Here, we approach this issue by using a novel network science approach to map bilingual spontaneous CS speech. In Study 1, we constructed semantic networks on CS speech corpora and conducted community detections to depict the semantic organizations of the bilingual lexicon.

The effects of temperature on the proxies of visual detection of larvae: observations from the optic tectum.

Numerous studies have indicated that temperature improves the visual capabilities of different ectotherms, including a variety of fish species. However, none of these studies has directly tested whether elevated temperature extends the visual detection distance - the distance from which a visual stimulus is detected. To test this hypothesis, we investigated the effect of temperature on the visual detection distance of zebrafish () larvae by measuring the largest distance from a moving target that induced a neural response in the optic tectum.

Kairomone-like activity of bile and bile components: A step towards revealing the chemical nature of fish kairomone.

Despite the efforts of a number of research groups worldwide, we still have a poor understanding of the chemical nature of the fish kairomones which induce defensive morphology, life history and behavior in their planktonic prey. Bile excreted by foraging fish play a crucial role in their signaling systems. Using high-performance liquid chromatography (HPLC), we revealed the presence of primary and secondary bile acids and bile salts in fish-conditioned water, similar as in carp bile.

Morphological deformation of Daphnia magna embryos caused by prolonged exposure to ibuprofen.

The effect of chronic exposure of freshwater cladoceran Daphnia magna to low, environmentally relevant concentrations i.e 4 μgLof ibuprofen (a nonsteroidal anti-inflammatory drug) in a laboratory experiment was studied. We observed the key life history traits of first and fifth generation individuals: age and size at first reproduction, number of first clutch eggs and individual growth rate.

Dexamethasone affects day/night development and function of thymus-derived T regulatory cells.

Thymus-derived T regulatory (tTregs) cells play a crucial role in the maintenance of tolerance and immune homeostasis. Mechanisms and factors regulating tTreg development and function are widely investigated, but to a large degree still remain unclear. Our previous findings demonstrated that, in physiological conditions, the development and suppressive function of tTregs demonstrated day/night rhythmicity, which correlated with the concentration of plasma corticosterone and the expression of glucocorticoid receptors.

Daily Profiles of Neuropeptides, Catecholamines, and Neurotransmitter Receptors in the Chicken Pineal Gland.

The avian pineal gland is one of three central biological clocks that contain all the components of a circadian system: a photoreceptive input, oscillator, and rhythmically secreted melatonin (MEL) as an effector. The biosynthesis of MEL is regulated by the neurotransmitters noradrenaline (NA), vasoactive intestinal peptide (VIP), and pituitary adenylate cyclase-activating polypeptide (PACAP). The aim of the present study was to characterize the daily profile of neurotransmitters and their receptors in the pineal gland of male Hy-Line chickens housed under controlled light (12:12 light:dark) conditions.

Daily profiles of melatonin synthesis-related indoles in the pineal glands of young chickens (Gallus gallus domesticus L.).

The aim of the present study was to characterize the daily profiles of melatonin synthesis-related indoles in the pineal glands of male Hy-Line chickens hatched in the winter and reared under controlled light (L:D 12:12) conditions. The pineal glands were isolated from 16-day-old birds immediately after decapitation every 2h over a 24-h period. The indole contents were measured using HPLC with fluorescence detection.

Avian biological clock - Immune system relationship.

Biological rhythms in birds are driven by the master clock, which includes the suprachiasmatic nucleus, the pineal gland and the retina. Light/dark cycles are the cues that synchronize the rhythmic changes in physiological processes, including immunity. This review summarizes our investigations on the bidirectional relationships between the chicken pineal gland and the immune system.

Day/night changes of thymus-deriving natural regulatory T cell development and function.

Activity of the immune system shows day/night rhythmicity. Changes in the migration and biological activities of immune cells are strongly regulated by the HPA axis. Another mechanism governing the level of the immune response is based on the suppressive activity of natural regulatory T cells CD4+CD25+Foxp3+ (nTregs) which play a crucial role in the maintenance of self-tolerance and immune homeostasis.

Photoperiod-related changes in hormonal and immune status of male Siberian hamsters, Phodopus sungorus.

Previously we have demonstrated that in Siberian hamsters some immune measures, especially the development of experimentally evoked peritonitis, varied in a photoperiod- and gender-dependent manner. The aim of the present study was to investigate whether the photoperiod-related differences in the activity of inflammation-involved immune cells are in this species attributed to the changes in the pineal gland function and/or hormonal status. Male hamsters housed in short day (SD), compared with those from long day (LD) conditions, exhibited significantly reduced plasma testosterone concentration and elevated cortisol and melatonin levels, the latter resulting from increased activity of hydroxyindole-O-methyltransferase (HIOMT).

Diurnal differences in melatonin effect on intracellular Ca2+ concentration in chicken spleen leukocytes in vitro.

Melatonin plays a pleiotropic role in the immune system of mammals and birds. Endogenous and exogenous melatonin modulates lymphocyte proliferation via specific MT(1), MT(2) and Mel(1c) membrane receptors, although the mechanisms behind this process are poorly understood. The diurnal changes in the expression and function of melatonin membrane receptors within the immune system have so far received little attention.

Functional MT1 and MT2 melatonin receptors in mammals.

Melatonin, dubbed the hormone of darkness, is known to regulate a wide variety of physiological processes in mammals. This review describes well-defined functional responses mediated through activation of high-affinity MT1 and MT2 G protein-coupled receptors viewed as potential targets for drug discovery. MT1 melatonin receptors modulate neuronal firing, arterial vasocon-striction, cell proliferation in cancer cells, and reproductive and metabolic functions.

Season- and gender-dependent changes in the immune function of Siberian hamsters (Phodopus sungorus).

Objectives: Siberian hamsters are photoperiodic animals exhibiting seasonality of reproduction and other physiological functions. Thus, the influence of photoperiod on the in vitro activity of selected immune cells from male and female hamsters challenged with peritoneal inflammation was examined.

Methods: Animals were housed for 8-10 weeks in LD (L:D=18:6) or SD (L:D=6:18).

Intracellular second messengers involved in melatonin signal transduction in chicken splenocytes in vitro.

The pineal hormone melatonin exhibits immunomodulatory activity well documented in mammals and birds. The mechanism of melatonin action within the immune system is, however, poorly understood. In mammalian immune cells in vitro, melatonin acts mainly as an antiapoptotic, oncostatic and antiproliferative agent, and these effects are exerted via specific receptors or are related to its free radical scavenging activity.

Bidirectional communication between the pineal gland and the immune system.

The pineal gland is a vertebrate neuroendocrine organ converting environmental photoperiodic information into a biochemical message (melatonin) that subsequently regulates the activity of numerous target tissues after its release into the bloodstream. A phylogenetically conserved feature is increased melatonin synthesis during darkness, even though there are differences between mammals and birds in the regulation of rhythmic pinealocyte function. Membrane-bound melatonin receptors are found in many peripheral organs, including lymphoid glands and immune cells, from which melatonin receptor genes have been characterized and cloned.

Influence of melatonin on chicken lymphocytes in vitro: involvement of membrane receptors.

Objectives: Time-dependent melatonin effects on chicken lymphocyte proliferation in vitro and the involvement of cAMP in melatonin signal transduction were examined.

Materials And Methods: Splenocytes and peripheral blood mononuclear cells (PBMC) were cultured in vitro in the presence of melatonin, phytohemagglutinin, luzindole, dibutyrylcAMP (dbcAMP), forskolin and vasoactive intestine peptide (VIP). Proliferation was measured by [(3)H]-thymidine incorporation in cultures carried out for 24, 36, 48 and 72 h.

Effect of morphine on thioglycollate-induced peritonitis in chickens.

Background: Morphine exerts immunomodulatory effects dependent on several factors including species and parameter examined. The aim of this study was to assess the influence of morphine on experimental peritonitis and leukocyte activity in young chickens of both sexes.

Methods: Peritonitis was elicited by intraperitoneal injection of thioglycollate (TG) alone or supplemented with morphine; additional chicken groups were injected with morphine alone.

Effect of immunization on nocturnal NAT activity in chicken pineal gland.

OBJECTIVES: The effect of a single immunization with sheep red blood cells (SRBC) on the nocturnal NAT activity in the pineal gland and serum anti-SRBC agglutinin titer was examined in the young, sexually immature ASTRA S chickens. METHODS: 3-, 4-, and 5-week-old birds of both sexes, hatched in long (Spring) and short (Autumn) day, were housed from hatching in controlled light (L:D = 12:12) and temperature conditions. Quantity of produced 14C-labeled N-acetyltryptamine was used as a measure of the nocturnal NAT activity in the pineal gland.