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Antiepileptic drugs may have varying toxicity or efficacy depending on administration time. VPA administration could be associated with a great deal of haematological toxicity and can cause aplasic anaemia or peripheral cytopenia affecting one or more cell lines. The objective of this study is to experimentally verify if VPA-induced haematological toxicity in mice varies according to drug administration time in the 24 h scale. Different groups of mice received 620 mg/kg of VPA by i.p. route at four different circadian stages. The results obtained showed that VPA treatment induced a significant decrease in the haematological parameter rates (cytopenia) depending on the circadian time; otherwise the Cosinor analysis showed that each haematological variable followed a significant blood type circadian physiological rhythm in controls and in treated mice. The highest significant haematological toxicity illustrated by the leucopenia index and thrombocytopenia was observed in the middle of the dark-activity phase (19 HALO). Chronotherapy may play an important role in improving the control of seizures and limiting the adverse effects of VPA treatment. Indeed, the data obtained indicate that the optimal haematological tolerance is observed when VPA was injected in the middle of the light-rest span of mice, which is physiologically analogous to the end of the activity of the diurnal phase in human patients.

Toxins are produced by bacteria, plants and animals for defense or for predation. Most of the toxins specifically affect the mammalian nervous system by interfering with the transmission of nerve impulses, and such toxins have the potential for misuse by the military or terrorist organizations. This review discusses the origin, structure, toxicity and symptoms, transmission, mechanism(s) of action, symptomatic treatment of the most important toxins and venoms derived from fungi, plants, marine animals, and microorganisms, along with their potential for use in bioweapons and/or biocrime. Fungal trichothecenes and aflatoxins are potent inhibitors of protein synthesis in most eukaryotes and have been used as biological warfare agents. Ricin and abrin are plant-derived toxins that prevent the elongation of polypeptide chains. Saxitoxin, anatoxin, and tetrodotoxin are marine-derived toxins that bind to sodium channels in nerve and muscle tissue and cause muscle paralysis. Most bacterial toxins, such as botulinum and Shiga affect either the nervous system (neurotoxins) or damage cell membranes. Batrachotoxins, which are secreted by poison-dart frogs are extremely potent cardiotoxic and neurotoxic steroidal alkaloids. The aim of this review is to provide basic information to enable further understanding of these toxins and their potential military uses.

Indoxyl sulfate (IS), a uremic toxin, is considered as a risk factor for accelerated atherosclerosis in patients with chronic kidney disease. As uptake of oxidized low-density lipoprotein (Ox-LDL) in macrophages is a key event in the progression of atherosclerosis, the aim of this study was to determine direct effects of IS on uptake of Ox-LDL in macrophages. Flow cytometric analysis revealed that IS significantly stimulated Ox-LDL uptake by THP-1 macrophages in both dose- and time-dependent manners. A CD36 inhibitor, sulfosuccinimidyl oleate (SSO), and ERK1/2 inhibitors, PD98059 and U0126, could suppress the IS-stimulated Ox-LDL uptake. IS also stimulated CD36 expression, which was inhibited by PD98059 and U0126. Western blotting analysis showed that IS significantly activated ERK1/2 mitogen-activated protein kinase (MAPK) pathway by increasing its phosphorylation level. Further, CCK-8 assay showed that IS exerted its effects without affecting cell viability. In conclusion, IS stimulated Ox-LDL uptake through up-regulation of CD36 expression in THP-1 macrophages, partly via ERK1/2 MAPK pathway. This might be one of the mechanisms underlying the progression of atherosclerosis in patients with chronic kidney disease.

The cell wall is no longer considered an inert and silent structure on the outside of the cell but instead, seems to be involved in an extensive cross-talk with the cytoplasm. Turgor, osmosensing, mechanical stress and other strains - all are mediated through the wall. The walled cell senses these signals through integral plasma membrane proteins whose extracytoplasmic domains are extended to the wall and intracytoplasmic domains are coupled with the components of cytoplasmic signal pathways. With its dynamic interactions the cell wall is comparable with the extracellular matrix of animal cells. Only a small part of the sensory machinery has been revealed in both plant and fungal cells.

Circulating fibrocytes (CFs) exhibit an extraordinary degree of plasticity and growth factor repertoire, and because of this they have been investigated for their role in the repair and regeneration of damaged tissues, but yet not adequately for their role in wound healing. In the present study, CFs were co-cultured with keratinocytes (KCs) or fibroblasts (Fbs) and the influences of CFs on the growth, proliferation and migration of KCs and Fbs were investigated. Our results showed that the CFs in the co-culture system could inhibit the growth, proliferation and migration of KCs, while CFs promoted the growth and proliferation of Fbs. Our study demonstrates that CFs can regulate the functions of Fbs, which may be a possible cause of fibrosis.

Antenatal glucocorticoid administration is used in cases of fetuses at risk to be born prematurely to enhance fetal pulmonary surfactant production and prevent infant respiratory distress syndrome. The CYP1A1 is the most important xenobiotic-metabolizing cytochrome P450 enzyme in the human placenta. Importantly, CYP1A1 generates reactive species and its placental activity is elevated in smoking women. CYP1A1 expression is mainly controlled by aryl hydrocarbon receptor (AHR) ligands. Glucocorticoid co-regulation of CYP1A1 has been described in various cell types but has not been systematically examined in the human placental trophoblast.
We studied the effects of the glucocorticoids dexamethasone and betamethasone on inducibility of CYP1A1 and other AHR target genes CYP1A2, CYP1B1, UGT1A1 (UDP-glucuronosyltransferase 1A1) and BCRP (Breast cancer resistance protein) by prototype AHR ligand 3-methylcholanthrene (3MC) in isolated human placental trophoblast culture.
We show that glucocorticoids alone had no effect on activity and protein/mRNA expression of CYP1A1 and little effect on mRNA expression of other AHR target genes. However, glucocorticoids significantly stimulated CYP1A1 mRNA, but not CYP1A2, CYP1B1, UGT1A1 and BCRP mRNAs, induction mediated by the AHR ligand. Consistently, glucocorticoids significantly augmented 7-ethoxyresorufin-O-deethylation (EROD) enzymatic activity in primary human placental trophoblast. Dexamethasone did not influence AHR and ARNT (Aryl hydrocarbon receptor nuclear translocator) mRNAs, suggesting that this phenomenon is not due to AHR or ARNT up-regulation by glucocorticoids in human trophoblast.
In conclusion, our data suggest that glucocorticoids have no effect on AHR target genes expression per se, but they may potentiate CYP1A1 induction in human term placental trophoblast.

The effects of acoustic waves on membrane structures, and any resulting consequences of this treatment on membrane subunit structures, remain poorly understood, as are the principals of related clinical effects. With a focus on morphological changes in the nuclear envelope, the current study presents detailed observations of membrane structures exposed to therapeutic ultrasound. Ultrasound treatment most commonly resulted in distinct changes in the distribution of nuclear pore complexes (NPCs) and mean NPC number per unit area after 30 min of repair, as well as alterations in NPC diameters on the protoplasmic face of fractured nuclear membranes after 10 min of repair. The greatest effects of ultrasound on nuclear envelope structure and NPCs were not to appear immediately, but became evident after repair processes were initiated. Results from the current study may contribute to the general view on the biophysical effects of therapeutic ultrasound on cell morphology and, particularly, the understanding of this effect in relation to the nuclear envelope.

The knowledge on the heterochromatin condensation state (HChCS) in central nuclear "gene rich" regions is limited although the heterochromatin reflects the gene silencing. Therefore, the HChCS in these regions was studied in proliferating granulocytic progenitors and terminally differentiated (mature) neutrophilic granulocytes. The HChCS was measured using computer assisted image optical densitometry at the single cell level. The bone marrow smears of patients with chronic myeloid leukemia represented a convenient model because of the increased number of progenitor and mature cells for density measurements. In addition, the heterochromatin density of central nuclear regions was also measured in myeloblasts of the K 562 cell lineage originated from the patient with that disease. The HChCS in central nuclear regions of both granulocytic progenitors and mature granulocytes was heterogeneous. The maximal and minimal density values were about 9-10 per cent above and below mean values in both myeloblasts and mature granulocytes. The heavy condensed heterochromatin of central nuclear region might reflect the location of silent genes during the whole granulocytic development. In contrary, the less condensed heterochromatin structures in central nuclear regions of granulocytic progenitors and mature granulocytes might just represent foci with the potential for the gene activation regardless of the differentiation and maturation stage. The HChCS in central nuclear regions was larger in small nuclear segments of mature granulocytes than in large nuclei of their progenitors. The HChCS was also increased in apoptotic K 562 myeloblasts with the decreased nuclear diameter. Such phenomena opened an "old - new" question on mutual relationship between the reduced nuclear size and the HChCS.

Despite numerous publications on nucleoli, their participation in terminal maturation and programmed cell death have not been studied extensively. On the other hand, some observations clearly indicate that terminal maturation and programmed cell death are accompanied by marked nucleolar changes which reflect the cessation of nucleolar biosynthetic activities. In addition, nucleolar changes in the course of terminal maturation may precede programmed cell death.

A survey of the current knowledge on stem cells and cell proliferation in turbellarians is presented, with special focus on recent results obtained by the authors when studying cell kinetics and cultivating neoblasts from various species. Differentiated somatic cells do not divide in flatworms. In these animals neoblasts constitute a proliferative compartment. These cells are rather uniform when viewed through a light microscope, but constitute a heterogeneous population comprising actual stem cells, progenitors and early differentiation stages. Cell kinetics were monitored by the incorporation of 5-bromo-2'-deoxyuridine and by immunocytochemical staining for mitoses in the marine microturbellarians Macrostomum, Microstomum and Convolutriloba. Distribution patterns of proliferating cells within the body were documented, and a tentative interpretation of the differences observed is given. Correlations to the nervous system and the mode of reproduction seem to exist. To analyse neoblasts quantitatively and establish primary cultures, neoblasts from the freshwater planarians (triclads) Dugesia and Schmidtea were isolated, purified and subjected to various culture conditions, with the ultimate but not yet achieved goal of establishing a permanent stem cell line. The role of stem cells in flatworms is compared with the situation in mammals, with special focus on embryogenesis, germline and strategies of cell renewal.

This paper discusses new methods for 3-D processing of confocal microscope outputs - single optical cuts through an explored object. The method can model cell illumination by an external light source and is a next important step in the realistic displaying of cells. The computer program based on these methods can be run on a common PC.

The present study was undertaken to provide more information on the heterochromatin density in central and peripheral nuclear regions during "cell dedifferentiation" represented by blastic transformation of mature T lymphocytes. Heterochromatin was visualized using a simple cytochemical method for the demonstration of DNA followed by computer-assisted densitometry of digitised images. The results indicated that the blastic transformation was accompanied by a marked and significant decrease in the heterochromatin density at the nuclear membrane. Thus, this nuclear peripheral region seems to be important not only for cell differentiation but also dedifferentiation events. It is also interesting that the non-stimulated resting mature cells in the present study were characterized by less condensed heterochromatin at the nuclear membrane than differentiated granulocytic or erythrocytic precursors and apoptotic myeloblasts or leukemic B lymphocytes described in the previous study. However, in contrast to these cells, resting and mature T lymphocytes in the present study are known to revert to cycling blastic cells after PHA treatment. In addition, it is also known that nuclear peripheral regions with heterochromatin represent sites of chromosomal attachments as well as "together crowded replicons" and silent genes.

The appearance of heterochromatin is generally accepted as a useful tool for the evaluation of the cell state including pathology; however, information on the heterochromatin DNA condensation state expressed by the image optical density in interphase nuclear regions and mitotic chromosomes with silent genes is very limited. Since human proliferating myeloblasts are a very convenient model, they were studied in the bone marrow of leukemic patients and established cell cultures using computer assisted image densitometry at the single cell level after heterochromatin visualization by a simple but sensitive cytochemical procedure for demonstration of DNA. As was expected, a high DNA image optical density was noted in central heterochromatin regions in contrast to the nuclear periphery at the nuclear envelope. Similarly, a high nuclear DNA image optical density was also expressed in mitotic chromosomes. Thus the possibility exists that the large heterochromatin DNA condensation expressed by the large image optical density in central nuclear regions, as in mitotic chromosomes, is related to silent gene locations. The similar width of mitotic chromosomes and chromatin fibrils in the heterochromatin regions in the interphase nuclei supports that explanation. The chromatin DNA fibrils in the central heterochromatin nuclear regions of interphase cells might just represent masked silent chromosomal segments. Such a conclusion is in harmony with "classical" cytology in the first part of the last century, which suggests the chromosome continuity from the mitotic division to the interphase where each chromatin region ("Kernbezirk") actually represents a chromosomal territory.

Microreactor technology is an interdisciplinary field that combines science and engineering. This new concept in production, analysis and research is finding increasing application in many different fields. Benefits of this new technology pose a vital influence on chemical industry, biotechnology, the pharmaceutical industry and medicine, life science, clinical and environmental diagnostic. In the last few years, together with microplant development, a great part of research investigation is focused on integrated micro-systems, the so called micro-total-analysis-systems (μ-TAS) or lab-on-chip (LOC). They are devices that perform sampling, sample preparation, detection and date processing in integrated model. Cell sorting, cell lysis, single cell analysis and non-destructive single cell experiments on just one microreactor, makes the LOC platform possible. Clinical diagnostic devices are also leaning towards completely integrated, multiple sophisticated biochemical analyses (PCR amplification, cell lysis, separation and detection) all on a single platform and in real time. Special attention is also paid to the usage of microdevices in tissue. Tissue engineering is one of the most promising fields that can lead to in vitro tissue and organ reconstruction ready for implantation and microdevices can be used to promote the migration, proliferation and the differentiation of cells in controlled situations.

In the food industry, in the process of creating new agricultural plant products, and in the testing of anti-cancer drugs there is often a need to assay multiple samples of low molecular weight antioxidants, plant samples and foods rich in antioxidants, with minimal additional costs and low degrees of uncertainty. With these demands in mind, we decided to study the fully automated assay of antioxidants using not only automated sample measurements but also automated processing of samples and application of reagents. The automated pipetting system epMotion 5075 and the automated spectrophotometer BS 400 were chosen for the assay purposes. Five methods were introduced for the automation: 2-diphenyl-1-picrylhydrazyl (DPPH) test, ferric reducing antioxidant power (FRAP) method, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) based test, N,N-dimethyl-1,4-diaminobenzene (DMPD) based test and the free radicals method. Samples containing one of the four antioxidants (standard rutin, quercitrin, ferulic and gallic acid) in a range 1-1000 μg/ml were used throughout. All of the tested methods were found suitable for implementation in an automated assay. However, some of them, such as the ABTS test failed to assay all tested antioxidants. The coefficients of determination were also unequal. From the analytical point of view, FRAP methods provided the most reliable results in the automated assay; because of the capacity of the method, approximately 240 samples per hour (one sample per 15 seconds) can be assayed using the automated protocol. We were encouraged by the data received and we expect further interest in the practical performance of such automation. As a mean of testing the robustness of our method, in the next step of our study, oxidative status was assessed in model cell lines derived from prostate cancer (PC-3, PNT1A and 22RV1) that were cultured on ellipticine (0, 0.5, 1, 1.5, 2, 2.5, 5, 7.5, 10, 15 μmol/l) supplemented agar. Antioxidant activity was assessed (DPPH, ABTS, FRAP, DMPD, FR) and calculated on the phenolic antioxidant level (rutin, quercitrin, ferulic and gallic acid), and thus an estimation was formulated of the oxidative stress as a result of the impact of anti-cancer drugs. It can be demonstrated that the new method has wide applicability.

Recently, oxidative stress has been identified as a pivotal pathological factor inducing bone osteoporosis. This phenomenon is responsible for low bone density. It alters bone quality and generates bone fractures. Strontium is found to induce osteoblast activity by stimulating bone formation and reducing bone resorption by restraining osteoclasts. Bioglass (BG) has been used to repair bone defects, and, in combination with strontium (BG-Sr), offers an opportunity to treat this disease. This study investigated the potential role of BG-Sr in improving antioxidant activity and regenerative bone capacity, The effects of both BG-Sr and BG were tested on osteoblast SaOS2 and endothelial EAhy926 cell proliferation in vitro. In vivo, BG-Sr and BG were implanted in the femoral condyles of Wistar rats and compared to that of control groups. Cell proliferation increased significantly by 120% at SaOS2 and 127% at EAhy926. Superoxide Dismutase (SOD), Catalase (CAT) and Glutathione Peroxidase (GPx) were significantly enhanced in BG-Sr treated rats compared to other groups. Moreover, a significant decrease of thiobarbituric acid-reactive substances (TBARs) was observed. The Ca/P ratio increase improved progressive bone mineralization. According to these results, BG-Sr ameliorated cell proliferation and developed an antioxidative defense against ROS. The histological findings highlight the BG-Sr implications in the osteoporosis treatment confirmed by bone construction. The development of BG-Sr as a therapeutic biomaterial protecting against oxidative stress might make an effective choice for application in tissue engineering.

Congenital abnormalities, various diseases and injuries may result in the degeneration of articular cartilage. Recently, stem cell therapy has offered new treatment possibilities for this condition. The aim of our study was to verify the chondrogenic differentiation potential of human bone marrow mesenchymal stem cells (BMSCs) and adipose tissue-derived mesenchymal stem cells (AMSCs) in vitro in the presence or absence of transforming growth factor beta (TGF-β1). Human BMSCs and AMSCs from healthy donors were collected during orthopaedic surgeries and expanded in vitro to obtain a sufficient quantity of cells; their chondrogenic differentiation was studied in the pellet culture system. Spontaneous chondrogenesis occurred in both BMSC and AMSC pellet cultures and was similar in both TGF-β1 treated and untreated pellet cultures. BMSC pellets contained more cells with a chondrogenic phenotype. The presence of TGF-β1 led to a decrease in the levels of collagen type I mRNA and to increased levels of collagen type II mRNA only in the BMSC pellet culture. Our results demonstrate that although both mesenchymal cell types can be used in cartilage tissue engineering, the chondrogenic potential of human BMSCs is higher than that of AMSCs.

At present it is clear that nucleoli are multifunctional cell organelles and participate in the cell proliferation, resting state, differentiation, maturation, aging and death. Therefore, they also represent very useful morphological markers of these cell states under physiological, pathological and experimental conditions. One of important nucleolar functions related to the mentioned cell states represents the transcription of ribosomal RNA and assembly of pre-ribosomal particles. Thus nucleoli participate in the creation of the cytoplasmic translation machinery necessary for the cell life and function. Although main nucleolar functions are already known, some of recently reported new additional functions depend on the role of a variety of nucleolar proteins some of which are not participating in the ribosomal biogenesis. It is natural that the role of newly discovered nucleolar proteins is still under discussions and remains to be clarified depending on new methodical approaches. It should be also mentioned that the visualization of some of these proteins and nucleolar localization also are and will be a subject for further studies.

Most of the pathophysiological processes of neurodegenerative diseases share the aggregation of related proteins which is one of the hallmarks of the degenerative processes. Recent advances in the knowledge of these proteinopathies show that the same protein could contribute to a number of diseases, thus suggesting a common pathological process. If this is so, specific instances of the brain neuronal system targeted by protein dysfunction could be a sign of a differential clinical expression rather than different pathological processes. This very stimulating view of the neurodegenerative diseases based on physiopathology has led us to suggest that possible degenerative mechanisms may be shared by different diseases although the causes of the disease itself still remain unclear. Since genetic forms of the degenerative diseases are rather rare, exploring the involvement of genes is one current way of researching the degenerative process of the disease. It is has thus been speculated that idiopathic forms of the diseases are related to close interactions between genetic and environmental factors; the genetic component being able to favour - or perhaps, to protect against - the disease process. Because of the current view that the basic mechanism of cell death in degenerative diseases is related to a rather limited number of processes in which oxidative stress could play a central role resulting in protein dysfunction and aggregation, one can speculate that there are neuroprotective medicines soon to be proposed based on the active limitation of protein accumulation in the brain.

Healthy cells strictly regulate gene transcription to control crucial cellular regulatory pathways. Members of the Jun protein family, c-Jun, JunB, and JunD are key subunits of the transcription factor AP-1 that controls transcription from various gene promoters. The genes targeted by Jun affect essential life processes, such as cell cycle progression, differentiation or programmed cell death. Therefore, the loss of proper Jun function is often associated with cancer. This review summarizes recent advances in understanding of function of the Jun proteins in healthy and cancer cells.

We selected important ethical conflicts of interest in current cell biology and which remain still unresolved: the use of human biological material, patents for biological material, cloning and use of stem cells, genetic engineering, onset of human life and death, and the use of vertebrate biomodels. New data from cell and molecular biology cannot facilitate the solution of such problems - on the contrary, they make these solutions more difficult. A solution may be found within the socio-cultural problems. Intensive research is necessary both to accomplish economical and medical benefit and to clarify ethical rules. Thus, essential cell biology seems to be the important part of education for non-life sciences students and students of biology and medicine would touch the social and ethical implications of recent biotechnologies in each knowledge-based economy.

Valerian is used to treat sleeping disorders, restlessness and anxiety, but it seems only to work when taken over long periods (several weeks). Some studies have demonstrated that valerian extracts interact with the GABA and benzodiazepine receptors. Valerian is also used traditionally to treat gastrointestinal pain and spastic colitis. There are no long term safety studies. Valerian contains over 150 chemical constituents and many of them are physiologically active, mainly pyridine alkaloids, some organic acids and terpenes, especially the so called valepotriates, esterified iridoid-monoterpenes. As valepotriates may be potential mutagens, valerian should only be used after consultation with a physician. Valerian medication is sometimes recommended as first line treatment when the benefit-risk relation requires it and is often indicated as transition medication during the discontinuation processes involving bromazepam, clonazepam and diazepam, among others.

The applications of gas plasma and plasma modified materials in the emerging fields of medicine such as dentistry, drug delivery, and tissue engineering are reviewed. Plasma sterilization of both living and non-living objects is safe, fast and efficient; for example plasma sterilization of medical equipment quickly removes microorganisms with no damage to the tiny delicate parts of the equipment and in dentistry it offers a non-toxic, painless bacterial inactivation of tissues from a dental cavity. Devices that generate plasma inside the root canal of a tooth give better killing efficiency against bacteria without causing any harm to the surrounding tissues. Plasma modified materials fulfill the requirements for bioactivity in medicine; for example, the inclusion of antimicrobial agents (metal nano particles, antimicrobial peptides, enzymes, etc.) in plasma modified materials (polymeric, metallic, etc.) alters them to produce superior antibacterial biomedical devices with a longer active life. Thin polymer films or coating on surfaces with different plasma processes improves the adherence, controlled loading and release of drug molecules. Surface functionalization by plasma treatment stimulates cell adhesion, cell growth and the spread of tissue development. Plasma applications are already contributing significantly to the changing face of medicine and future trends are discussed in this paper.

Arsenic trioxide (As₂O₃, ATO) is a very efficacious, clinically established agent for the treatment of acute promyelocytic leukaemia, and also potentially useful against other haematological and non-haematological malignancies. Nonetheless, the relative resistance of many tumour cell types requires the generation of sensitizing strategies. One of the properties of ATO which might be exploited for therapeutic purposes is its sensitivity to the intracellular oxidant state, as revealed by increased apoptosis production under conditions of reduced glutathione (GSH) depletion and/or elevated reactive oxygen species (ROS) content. This review summarizes some studies from our laboratory demonstrating that experimental modulation of protein kinase activities (PI3K/Akt, JNK, MEK/ERK) potentiates ATO-provoked apoptosis in relatively resistant human acute myeloid leukaemia (U937, HL60) cell lines by mechanisms involving GSH depletion and/or increased ROS content. In a similar manner, co-treatment with dietary flavonoides such as genistein, normally considered as anti-oxidants, may potentiate apoptosis via generation of moderate oxidative stress and activation of ROS-inducible protein kinases. Finally, co-treatment with ATO may sensitize otherwise refractory leukaemia cells to TNFα-family cytokine-produced apoptosis, by mechanisms involving the interplay between the "intrinsic" (mitochondrial) and "extrinsic" (death receptor-mediated) pathways.

One of the many systems that weakens as we age is our immune system and there is a reduction in the GH-IGF1 axis activity with increasing age. In this study we evaluated the immune system and the GH-IGF1 axis function in healthy ageing. CD3, CD4, CD20, CD25, HLA-DR and GH showed acrophase during the night, whereas CD8, CD16 and TCRγδ expressing cells showed acrophase during the day. MESOR of CD3 was higher in the old aged subjects, MESOR of CD20 and CD20 values at 14:00h and at 02:00h were higher in the young middle aged subjects, MESOR of CD25 and CD25 values at 10:00 were higher in the elderly subjects, MESOR of HLA-DR was higher in the young middle aged subjects, whereas MESOR of DR+T cells and HLA-DR at 02:00h were higher in the elderly subjects, MESOR of TCRγδ bearing cells was higher in the elderly subjects, GH value at 18:00h was also higher in the elderly subjects, and MESOR of IGF1 was higher in the young middle aged subjects. There was a statistically significant difference for the acrophases of CD25, HLA-DR and IGF1. There were different and opposing correlations among lymphocyte subpopulations and GH-IGF1 axis hormones in young and middle aged subjects in comparison with old aged subjects. Linear regression evidenced a statistically significant positive trend between age and the 24h mean of CD3 and CD25 and a statistically significant negative trend between age and the 24h mean of CD20 and GH. In conclusion, ageing is associated with an altered GH and IGF1 secretion, with decreased peripheral B cell compartment, increased peripheral T cell compartment and alterations of circadian rhythmicity.

Histone acetyltransferase and histone deacetylase activities determine the acetylation status of histones, and have the ability to regulate gene expression through chromatin remodeling. A controlled balance between histone acetylation and histone deacetylation appears to be essential for normal cell growth. In cancer cells, some genes are repressed by inappropriate recruitment of histone deacetylases. The histone deacetylase inhibitors (HDACI) belong to the class of anticancer drugs that are effective in killing proliferating and non-proliferating tumor cells. In this review we discuss molecular mechanisms involved in the induction of cell cycle arrest, differentiation and induction of apoptosis in tumor cells by HDACI.

Tyrosine kinase (TK) activity in primary mononuclear blood cells (MNBC) derived from chronic myelogenous leukemia (CML) patients in the chronic phase as well as from healthy donors was measured by a sensitive time-resolved fluorescence method using the Delfia® Tyrosine Kinase kit. The level of phosphotyrosine was assessed in parallel by flow-cytometry. The experimental protocol for Delfia® was optimized using a K562 cell line. A large part (20 to 50%) of the fluorescence signal from K562 cells was sensitive to Imatinib mesylate, an inhibitor of Bcr-Abl tyrosine kinase, which is currently the leading drug in CML treatment. In primary MNBC, the direct contribution of Bcr-Abl itself to the signal was low. However, a 48h treatment of MNBC with 5 μM Imatinib resulted in a significant reduction of the observed TK activity (mean TK activity value: 56% of control) paralleled by a decrease in the phosphotyrosine level in the CML group. Modification of TK activity by Imatinib was observed also in the donor group. Imatinib mesylate thus probably affects cell signalization even in Bcr-Abl negative cells.

Cell shape, adhesion, and motility are affected by Ca-regulated pathways, which depend on Ca-binding proteins. One such protein is calreticulin, a ubiquitous and major Ca-binding protein, resident in the ER of eukaryotic cells. In the lumen of the ER, calreticulin is a lectin-like chaperone, sharing this function with an ER-membrane protein, calnexin. Calreticulin also functions as an ER-lumenal Ca store and plays a central role in intracellular Ca homeostasis, including the regulation of store-operated Ca influx via plasma membrane and ER Ca channels. Calreticulin also affects processes outside of the ER; most notably, it modulates expression of several genes, some of them adhesion related, such as vinculin and fibronectin. Curiously, changes in the expression level of calreticulin strongly affect tyrosine phosphorylation of cellular proteins, which is known to affect many adhesion-related functions. Consequently, calreticulin affects cell adhesion via the regulation of expression of proteins important in adhesion, as well as via its effects on intracellular signalling pathways. One of the proteins differentially phosphorylated in a calreticulin-dependent manner is β-catenin, a structural component of cadherin-mediated adhesion complexes and a part of the Wnt signalling pathway. We suggest that the observed changes in cell adhesiveness may be due to calreticulin's influence on a signalling pathway from the ER, which includes the β-catenin/vinculin protein system. Differential expression of calreticulin may affect the phosphorylation status of β-catenin by either inhibition of specific phosphotyrosine kinase(s) or activation of phosphotyrosine phosphatase(s). This is likely to affect the balance between complexed and free β-catenin and impinge further down on the Wnt signalling. At present, the mechanism by which calreticulin affects gene expression can only be speculated upon, but our data indicate that calreticulin, via its effects on Ca release from the ER, may indirectly control the expression of several genes by interfering with calcineurin activity and the ability of the transcription factor, NFAT-3, to translocate to the nucleus. The activation of calcineurin depends on the sustained release of Ca from ER stores, which is dependent on calreticulin.
In summary, we propose that calreticulin may be a centrally located connector molecule in a signalling network in the lumen of the ER. Calreticulin is uniquely endowed for such regulation because it is a multifunctional protein that interacts with several other ER proteins in a Ca-dependent manner, suggesting that it may function as a signalling "toggle switch". We therefore hypothesize that calreticulin regulates gene expression by participating in an "ER-to-nucleus" signalling pathway, which parallels an "ER-to-cell surface" pathway based upon post-translational events.

The authors investigated whether cytosolic free calcium concentration ([Ca²⁺]c) plays a role in hydrogen peroxide-induced pancreatic acinar AR42J cells apoptosis. We analysed mitochondrial depolarization, [Ca²⁺]c determination and caspase-3 activity by fluorimetric methods, and cytochrome c release by subcellular fractionation and western blotting. The data shown that hydrogen peroxide, which causes a sustained [Ca²⁺]c increase, induces mitochondrial depolarization and cytochrome c release, and activation of caspase-3. Dimethyl-BAPTA loading did not affect hydrogen peroxide-evoked mitochondrial apoptosis, suggesting that these responses are independent of increases in [Ca²⁺]c. Treatment with thapsigargin, to induce extensive calcium store depletion and subsequent increases in [Ca²⁺]c, also stimulates mitochondrial depolarization cytochrome c release, and caspase-3 activation. Similar results were observed in AR42J cells loaded with dimethyl-BAPTA, suggesting that activation of apoptosis by thapsigargin does not require rises in [Ca²⁺]c. However, the blockade of mitochondrial calcium entry by pretreating with Ru360 showed protection against hydrogen peroxide- and thapsigargin-induced mitochondrial apoptosis. These results indicate that the apoptosis evoked by hydrogen peroxide and thapsigargin is mediated by mitochondrial calcium uptake.

Nanotechnology is an emerging field of science which is producing nano-sized materials. Some nanomaterials are having a significant impact in health care. Of these, carbon nanotubes (CNTs) represent one of the most promising materials in the field of nano-science and technology. Their potential in industrial applications has brought them much attention and the wide spectrum of usage has made it imperative that the impact of CNTs on human health and the environment is investigated thoroughly. In addition to their various beneficial applications, there is a potential for hazardous effects on human health. For example, the potential hazards through inhalation of CNTs have not been sufficiently evaluated. CNTs produce reactive oxygen species (ROS) which are associated with diminishing cellular activities, such as a decrease in the mitochondrial membrane potential etc. This paper reviews the hazardous influence of CNTs on human health and the environment. Specifically, the effects of CNTs on lung toxicity, skin irritation and CNTs cytotoxicity on various cell lines are reviewed. Biomedical applications and biocompatibility of carbon nanotubes are also summarized.