Audiological evaluation of patients with cleidocranial dysplasia (CCD)

OBJECTIVE

The description of clinical manifestation of hearing problems in cleidocranial dysplasia (CCD) remains limited and incomplete, since CCD constitutes a rare congenital disorder. The study aims to provide a complex panel analysis of the auditory system in patients suffering from the disease.

PATIENTS AND METHODS

The study group consisted of 4 children with CCD (aged: 12-15), who underwent orthodontic treatment. A full panel analysis of their auditory systems was performed, including high-frequency audiometry and a new method of middle ear assessment - WBT (Wideband Tympanometry).

RESULTS

A slight conductive hearing loss was diagnosed in 3 out of 4 patients. While high frequency audiometry has shown a deterioration of hearing in 3 patients, in one case, the obtained thresholds were within the normal range. A decrease of absorbance in low frequencies has been observed in one or both ears. Only one patient has had a shift of maximum absorbance towards high frequencies in the left ear.

CONCLUSIONS

The presented manuscript is the first with a complete evaluation of the auditory system comprising 4 cases of children in a similar age group. All of the examined patients presented an air-bone gap indicating conductive disorders.

Diversifying selection signatures among divergently selected subpopulations of Polish Red cattle

Polish Red cattle is one of the few indigenous breeds of European red cattle which is characterized by several desired features, such as high disease resistance, good health, longevity, good fertility, and high nutritional value of milk. Currently, Polish Red cattle population is a subject of two independent breeding programs: (i) improvement program and (ii) genetic resources conservation program. The aim of the improvement program is the genetic progress in terms of milk production and body conformation traits, while the conservation program mainly focuses on protection of the genetic resources of Polish Red cattle and preservation of the existing, original gene pool. By the analysis of F_ST genetic distances across genome-wide SNP panel, we detected diversifying selection signatures among these two subpopulations and indicated (among others) the significance of DGAT1 and FGF2 genes for milk production traits in these cattle. We also found that among genes being presumably under selection in terms of milk production, there are genes responsible, for example, for mammary gland development (e.g., SOSTDC1, PYGO2, MED1, and CCND1) and immune system response (e.g., IL10RA, IL12B, and IL21). The most important finding of this study is that the most pronounced genetic differences between the analyzed populations were associated with β-defensin genes (e.g., DEFB1, DEFB4A, DEFB5, DEFB7, DEFB10, DEFB13, EBD, BNBD-6, and LAP) located within so-called bovine cluster D on BTA27. The β-defensins are expressed mainly in the mammary gland and are antimicrobial peptides against the Gram-negative and Gram-positive bacteria, viruses, and other unicellular parasites. This suggests that antimicrobial resistance of mammary gland is of high importance during selection towards increased milk production and that genes responsible for this process are selected together with increasing levels of productivity.

The effect of palmitate supplementation on gene expression profile in proliferating myoblasts

High-fat diet, exposure to saturated fatty acids, or the presence of adipocytes in myoblast microenvironment affects skeletal muscle growth and function. The aim of the present study was to investigate the effect of palmitate supplementation on transcriptomic profile of mouse C2C12 myoblasts. Global gene expression was evaluated using whole mouse genome oligonucleotide microarrays, and the results were validated through qPCR. A total of 4047 genes were identified as differentially expressed, including 3492 downregulated and 555 upregulated genes, during a 48-h exposure to palmitate (0.1 mmol/l). Functional classification showed the involvement of these genes in several processes which regulate cell growth. In conclusion, the addition of palmitate modifies the expression of genes associated with (1) myoblast responsiveness to hormones and growth factors, (2) cytokine and growth factor expression, and (3) regulation of cell-cell and cell-matrix communication. Such alterations can affect myoblast growth and differentiation; however, further studies in this field are required.

Effects of the platelet-activating factor (PAF) on selected quality parameters of cryopreserved bull semen (AI) with reduced sperm motility

The aim of the study was to determine the effects of platelet-activating factor (PAF) on selected quality parameters of cryopreserved bull semen with reduced sperm motility used for artificial insemination. The aim of experiment 1 was to identify the optimal concentration of the phospholipid able to preserve sperm viability. Cryopreserved semen was treated with different PAF concentrations: 1×10-5M, 1×10-6M, 1×10-7M, 1×10-8M and 1×10-9M. The experiment demonstrated that PAF at concentration 1×10-9M increased most the sperm viability parameters (motility parameters, plasma membrane integrity and mitochondrial function) after 120 min of incubation of thawed semen at 37°C. Cryopreserved bull semen with reduced sperm motility (below 70%) was supplemented with PAF in a concentration of 1×10-9M. A statistically significant increase in sperm motility, percentage of linear motile spermatozoa and VSL value was observed after 120 min incubation of sperm with 1×10-9M PAF. Sperm supplementation with PAF also had positive effects on plasma membrane integrity and percentage of spermatozoa with preserved mitochondrial transmembrane potential, but the differences were not statistically significant. The results indicated positive effects of PAF supplementation at a concentration of 1×10-9M on the selected sperm quality parameters in cryopreserved bull semen with reduced motility.

Specific character of anaerobic bacterial infections in patients treated in transplantation wards at one of the clinical hospitals in Warsaw

Immunocompromised patients and patients undergoing invasive procedures are predisposed to bacterial infections, due to the possibility of micro-organism translocation from their physiological habitat. Infectious complications may occur both in the early and late post-transplantation periods. The purpose of this study was to evaluate the proportion as well as susceptibility profiles of obligatory anaerobes in the etiology of infections in patients hospitalized at transplantation wards of a large clinical hospital in Warsaw. A total of 104 strains of obligatory anaerobes derived from patients hospitalized in two transplantation clinics at a clinical hospital in Warsaw were evaluated. The strains were isolated from 87 clinical samples collected from 84 patients of two transplantation wards between 2007 and 2012. A total of 104 obligatory anaerobic bacterial strains were isolated and identified, with Gram-positive and Gram-negative bacteria constituting 60.6% and 39.4% of the isolates, respectively. Almost exclusively non-spore-forming anaerobes were detected in evaluated samples. The present study showed all isolated Gram-positive bacteria to be susceptible to ß-lactam antibiotics. Metronidazole-resistant bacteria were found among the genera Propionibacterium and Actinomyces. All Gram-negative rods were susceptible to imipenem and metronidazole. Among them, Bacteroides spp. and Parabacteroides distasonis showed resistance to penicillin G (100%). Because of their pathogenicity and altered antibiotic susceptibility profiles, the bacteria of the genera Bacteroides and Parabacteroides are of greatest clinical importance. Approximately 25% of isolates exhibit also resistance to clindamycin. Because of the growing rates of clindamycin resistance, the role of metronidazole in the treatment of Bacteroides spp. is of increasing importance.

Missense mutation in glutathione-S-transferase M1 gene is associated with sperm motility and ATP content in frozen-thawed semen of Holstein-Friesian bulls

Glutathione-S-transferase genes (GSTs) encode enzymes that are involved in detoxification and neutralization of reactive oxygen species (ROS) in male reproductive system and play protective role during spermatogenesis. The aim of the study was to evaluate whether C/G missense mutation (rs135955605) within glutathione-S-transferase M1 (GSTM1) gene is associated with selected parameters of frozen-thawed semen in 309 Holstein-Friesian bulls. Single nucleotide substitution C/G was identified by amplification of GSTM1 gene fragment followed be digestion with restriction enzyme DdeI. Bulls with GG genotype were the most frequent (67.96%), in comparison to CC (2.59%) and GC (29.45%). Significant associations were found between GSTM1 genotypes and ATP content and total sperm motility. Bulls with GG genotype had the highest values for both traits. Rare variant C of GSTM1 was associated with significant decrease of sperm motility and ATP content. Our results demonstrate that C/G missense mutation within GSTM1 gene is involved in bull sperm quality.

Selected qualitative and biochemical parameters of cryopreserved semen of Holstein-Friesian (HF) AI bulls

Selected qualitative and biochemical parameters were determined in cryopreserved semen used for artificial insemination, sampled from 120 bulls reared at the Animal Breeding and Insemination Center in Bydgoszcz. The total average motility of the analyzed sperm samples was determined at 62.51%. The percentage of motile spermatozoa displaying progressive forward motility was 21.65%. Analyzed samples were characterized by a high percentage of sperm cells with a intact plasma membrane (71.21%) and active mitochondria (71.32%). High efficiency of the enzymatic antioxidant system of the evaluated sperm cells was demonstrated by high activity of CAT, GPx and SOD (494.37, 2847.83 and 5.31U/1×109 spermatozoa, respectively) values and low values of the DNA Fragmentation Index (9.32). The results of the study, obtained with the involvement of advanced analytical methods, indicate a high fertilizing capability of the analyzed sperm samples.

Transcriptional background of beef marbling - novel genes implicated in intramuscular fat deposition

The purpose of this study was to identify novel marbling-related genes by comparison of the global gene expression in semitendinosus muscle of 15-month-old Limousin (LIM), Holstein-Friesian (HF) and Hereford (HER) bulls. Muscle of LIM was lean with low intramuscular fat (IMF) content (0.53%) unlike the marbled muscles of HER and HF characterized by higher amounts of IMF (1.10 and 0.81%, respectively). The comparison of muscle transcriptional profile between marbled and lean beef revealed significant differences in expression of 144 genes, presumably involved in consecutive stages of adipose tissue development, such as preadipocyte proliferation and differentiation, adipocyte maturation, lipid filling and lipid metabolism leading to increased IMF deposition and marbling development. Correlation coefficients and regression analysis for nine of them (gadd45a, pias3, ccrn4l, diras3, pou5f1, hoxa9, atp2a2 and pim1) validated by real-time qPCR confirmed their moderate-high correlation with IMF% and explained up to 70.5% of the total variability in IMF deposition in the bulls.

Primary cultures of murine neurons for studying herpes simplex virus 1 infection and its inhibition by antivirals

Herpes simplex virus 1 (HSV-1) establishes life-long latency in peripheral neurons, where productive replication is suppressed. To study the specific relationship between the virus and peripheral neurons that would not be affected by other cells usually present in in vivo systems, we present an in vitro model system based on primary cultures of murine neurons. This model system can be used for characterization of various virus strains and testing of cytotoxicity and inhibitory activity of acyclovir (ACV), cidofovir (CDV) and other antivirals.

Transcriptomic "portraits" of canine mammary cancer cell lines with various phenotypes

In light of the high incidence of mammary cancer in dogs and completion of the canine genome sequencing, the new possibilities of gene profiling by using DNA microarrays give hope to veterinary oncology. The cell lines isolated from mammary tumors are a valuable tool in developing and testing new pathway-specific cancer therapeutics. Differential cytometric analysis of 6 canine mammary cancer cell lines was performed. We divided cell lines into 3 groups based on their phenotype: 2 lines with high proliferative potential, 2 lines with high antiapoptotic potential, and 2 lines with high metastatic potential. DNA microarray analysis revealed common genes for cell lines of each group. We found that genes encoding the receptors for growth hormone and ghrelin are related to high proliferation rate, while ABR (active BCR-related) and TMD1 (TM2 domain containing 1) genes are related to a high antiapoptotic potential of the cancer cells. Metastatic properties of mammary cancer cells seem to be associated with elevated expression of PGP (P glycoprotein), SEMA3B (semaphorin 3B), and STIM1 (stromal interaction molecule 1).

Transcriptomic signature of cell lines isolated from canine mammary adenocarcinoma metastases to lungs

Metastasis is a final step in the progression of mammary gland cancer, usually leading to death. Potentially, a molecular signature of metastasis can be defined via comparison of primary tumors with their metastases. Currently, there is no data in the literature regarding the molecular portrait of metastases in dogs and only few reports regarding human cancer. This is the first report describing the transcriptomic signature of canine cancer metastatic cells. Two adenocarcinoma cell lines isolated from the canine mammary gland (CMT-W1 and CMT-W2) were compared with cell lines isolated from their lung metastases (CMT-W1M and CMT-W2M) with regards to the following cytometric parameters: cell cycle, ploidy, Bcl-2 expression, susceptibility to induced apoptosis, and transcriptomic profile. Cytometric analyses revealed significant differences in cell cycle and antiapoptotic potential between the examined cells. Using oligonucleotide microarrays, we found 104 up-regulated genes in the metastatic cell line CMT-W1M and 21 up-regulated genes in the primary CMT-W1 cell line. We also found 83 up-regulated genes in the CMT-W2M cell line and only 21 up-regulated genes in the CMT-W2 cell line. Among the up-regulated genes in both metastatic cell lines, we found 15 common genes. These differently expressed genes are involved mainly in signal transduction, cell structure and motility, nucleic acid metabolism, developmental processing, and apoptosis (GHSR, RASSF1, ARF1GAP, WDR74, SMOC2, SFRP4, DIAPH1, FSCN1, ALX4, SNX15, PLD2, WNT7B, POU6F2, NKG7, and POLR2F). Seven of them are involved in a cellular pathway dependent on ghrelin via growth hormone secretagogue receptor (GHSR). Our results suggest that this pathway may be essential for mammary cancer cells to have a metastatic potential.

Differences in growth and transcriptomic profile of bovine mammary epithelial monolayer and three-dimensional cell cultures

Mammary epithelial cells (MECs) are characterized by specific spatial architecture with several distinguishing features such as: polarized morphology, specialized cell-cell contacts, and attachment to an underlying basement membrane. Three dimensional (3D) basement membrane cultures provide a unique opportunity to model the architecture of epithelium in vitro. The aim of this study was to characterize the growth of bovine mammary epithelial cell line BME-UV1 in 3D culture on Matrigel and identification of differently expressed genes in bovine MECs forming polarized structures in comparison to conventional monolayer (2D) cell culture. We demonstrate that BME-UV1 cells grown on Matrigel form polarized acinar structures during 16 days of culture. A microarray study has proven that the difference in spatial architecture between MECs cultured in monolayer and 3D system is reflected by differences in transcriptomic profile. Microarray data analysis showed 40 differentially expressed genes with statistical significance (p<0.05) and characterized biological functions. Identified genes comprised of cytoskeletal proteins, extracellular matrix components, kinases such as: Rac serine/threonine kinase, SRPK, protooncogene tyrosine-protein kinase ABL1, uridine cytidine kinase and proteins with nucleic acid binding / transcription factor activity. Products of those genes are involved in processes which are known to participate in regulating mammary gland polarization and function.

Comparison of cellular and tissue transcriptional profiles in canine mammary tumor

Tumor-derived cell lines are widely used as in vitro cancer models. Cell lines historically served as the primary experimental model systems for exploration of tumor cell biology and pharmacology. However, their ability to accurately reflect the phenotype and genotype of the parental histology remains questionable, given the prevalence of documented cell line-specific cytogenetic changes. Sometimes cell line studies are interpreted in the context of artifacts introduced by selection and establishment of cell lines in vitro. This complication has led to difficulties in the extrapolation of biology observed in cell lines to tumor biology in vivo. The aim of our study was to compare gene expression profiles in canine mammary tumor tissue and cell cultures derived from those tumors using cDNA microarrays. Tumors of two different origins were used; chondrosarcoma and adenocarcinoma and their primary cell cultures. It has been found that cell culture gene expression profiles closely resembled those of their corresponding in vivo tumor. In adenocarcinoma and chondrosarcoma only 6.0% and 2.7% of genes respectively, have shown significant difference in expression. In the most cases the difference concerned up-regulation of gene expression in cell lines, particularly genes involved in: protein metabolism and modification, signal transduction and nucleotide, nucleoside and nucleic acid metabolism. These experiments revealed that transcriptome of our primary cell culture corresponds to transcriptome of its parental tumor tissue and for this reason cell culture represents the reliable in vitro model for oncogenomic and pharmacogenomic studies.

Increased serum levels of troponin I and lesions in coronary angiography in hemodialysed patients

PURPOSE

Calcium-phosphate disorders are a frequent finding in HD patients, and, in some cases, may cause an abnormal coronary calcification. Some of the HD patients have increased serum cTnI level without evidence of acute coronary syndrome. The aim of this study was to determine if there is a correlance between increased cTnI levels and presence of stenotic changes in coronary arteries in asymptomatic HD patients.

MATERIAL AND METHODS

In 13 of 119 HD patients (M:F 10:3) a coronary angiography was performed. The mean age of the patients was 53 years (33-76) and the mean HD duration was 55 months (3-156). cTnI was analyzed by AxSYM system and, subsequently, by VIDAS system.

RESULTS

A constant or intermittent elevation of cTnI was detected in 5 of 13 patients. In 10 of 13 pts a critical stenosis of at least 1 coronary artery was found. A critical stenosis was found in 4 of 5 cTnI (+) patients and in 6 of 8 cTnI (-) patients. An excess calcification of coronaries was observed in 7 patients, including 1 cTnI positive patient with no evidence of coronary stenosis.

CONCLUSIONS

1. The elevation of cTnI in asymptomatic HD patients is observed when there is: (I) excess calcification accompanied by a critical stenosis of at least 1 coronary artery, (II) a critical stenosis of 2 or more coronaries with no evidence of calcification. 2. We suggest that excess cardiovascular calcification in HD patients may be one of the major factors responsible for the troponin release.

On the function of dendritic spines

Dendritic spines occupy a strategic position in the central nervous system, yet their function is still under debate. Over the past decades, many hypotheses have been put forward to explain the specific function of spines. Recently, imaging experiments have demonstrated that spines compartmentalize calcium, a role that appears necessary for input-specific forms of synaptic plasticity. In addition, it has been discovered that spine morphology is plastic over fast time scales and can be controlled by specific biochemical pathways. Also, several aspects of the spine's morphology appear to be intricately linked to its function. The authors review these recent data and incorporate them into a model for the function of dendritic spines in CNS circuits. In their proposal, spines serve to specifically connect sparse inputs and therefore minimize the wiring necessary in the CNS while maximizing connectivity. By virtue of the same design, spines isolate inputs and thus implement local learning rules. These rules appear only necessary with sparse inputs so these two functions are intimately related. Spines therefore would play a crucial circuit role, remarkably analogous to synaptic matrix elements of associative neural networks. This model highlights the economical, yet elegant, design of CNS circuits.

Topology of gap junction networks in C. elegans

Gap junctions are prevalent in every nervous system, but their role in information processing remains largely unknown. In C. elegans, the role of gap junctional communication in touch sensitivity has been demonstrated. In this animal, the entire complement of gap junctions in the nervous system is documented, therefore providing a good model for the computational investigation of circuit functions of gap junctions.We explored several hypotheses about the role of gap junctions in the nervous system of C. elegans by systematically analysing an anatomical database with recursive algorithms. We find that gap junctions connect different sets of neurons from those connected by chemical synapses. In addition, when analysing the topology of the gap-junction networks, we find that, surprisingly, most (92%) neurons in the worm are linked in a single gap-junction network. The worm nervous system can only be divided into smaller networks by assuming that two or more gap junctions are necessary for functional coupling or that neural activity has limited propagation. However, these groups, and others identified using algorithms with subsets or combinations of restrictive criteria, do not correspond to any known circuits identified in genetic and behavioral studies. Finally, we notice that the function of some gap junctions appears linked to their precise location on the neuronal processes. We propose that the location of the gap junctions within the neuron determines their functional role.

A custom-made two-photon microscope and deconvolution system

We describe in detail a custom-built two-photon microscope based on a modified confocal scanhead (Olympus Fluoview) and mode-locked Ti:sapphire laser (Coherent Mira 900). This system has internal detectors as well as external whole-field detection and an electrooptical modulator for blanking the beam on flyback and effecting fast changes in excitation intensity. This microscope can be used in deep, scattering samples for quantitative measurements with a wide range of fluorophores (GFP, fura, calcium green, calcium orange, fluo-3, DiI, DiO, fluorescein, rhodamine), for fluorescent photobleaching recovery and for uncaging. Images obtained with this system can be deconvolved with the Estimation Maximization algorithm using the program XCOSM (freeware available at: http://www.ibc.wustl.edu/bcl/ xcosm/).

Regulation of spine calcium dynamics by rapid spine motility

Dendritic spines receive most excitatory inputs in the CNS and compartmentalize calcium. Spines also undergo rapid morphological changes, although the function of this motility is still unclear. We have investigated the effect of spine movement on spine calcium dynamics with two-photon photobleaching of enhanced green fluorescent protein and calcium imaging of action potential-elicited transients in spines from layer 2/3 pyramidal neurons in mouse visual cortex slices. The elongation or retraction of the spine neck during spine motility alters the diffusional coupling between spine and dendrite and significantly changes calcium decay kinetics in spines. Our results demonstrate that the spine's ability to compartmentalize calcium is constantly changing.

From form to function: calcium compartmentalization in dendritic spines

Dendritic spines compartmentalize calcium, and this could be their main function. We review experimental work on spine calcium dynamics. Calcium influx into spines is mediated by calcium channels and by NMDA and AMPA receptors and is followed by fast diffusional equilibration within the spine head. Calcium decay kinetics are controlled by slower diffusion through the spine neck and by spine calcium pumps. Calcium release occurs in spines, although its role is controversial. Finally, the endogenous calcium buffers in spines remain unknown. Thus, spines are calcium compartments because of their morphologies and local influx and extrusion mechanisms. These studies highlight the richness and heterogeneity of pathways that regulate calcium accumulations in spines and the close relationship between the morphology and function of the spine.

Mechanisms of calcium decay kinetics in hippocampal spines: role of spine calcium pumps and calcium diffusion through the spine neck in biochemical compartmentalization

Dendritic spines receive most excitatory inputs in the CNS and compartmentalize calcium. Although the mechanisms of calcium influx into spines have been explored, it is unknown what determines the calcium decay kinetics in spines. With two-photon microscopy we investigate action potential-induced calcium dynamics in spines from rat CA1 pyramidal neurons in slices. The [Ca(2+)](i) in most spines shows two decay kinetics: an initial fast component, during which [Ca(2+)](i) in spines decays to dendritic levels, followed by a slower decay phase in which the spine follows dendritic kinetics. The correlation between [Ca(2+)](i) in spine and dendrite at the breakpoint of the decay kinetics demonstrates diffusional equilibration between spine and dendrite during the slower component. To explain the faster initial decay, we rule out saturation or kinetic effects of endogenous or exogenous buffers and focus instead on (1) active calcium extrusion and (2) buffered diffusion of calcium from spine to dendrite. The presence of an undershoot in most spines indicates that extrusion mechanisms can be intrinsic to the spine. Supporting the two mechanisms, pharmacological blockade of smooth endoplasmic reticulum calcium (SERCA) pumps and the length of the spine neck affect spine decay kinetics. Using a mathematical model, we find that the contribution of calcium pumps and diffusion varies from spine to spine. We conclude that dendritic spines have calcium pumps and that their density and kinetics, together with the morphology of the spine neck, determine the time during which the spine compartmentalizes calcium.

Developmental regulation of spine motility in the mammalian central nervous system

The function of dendritic spines, postsynaptic sites of excitatory input in the mammalian central nervous system (CNS), is still not well understood. Although changes in spine morphology may mediate synaptic plasticity, the extent of basal spine motility and its regulation and function remains controversial. We investigated spine motility in three principal neurons of the mouse CNS: cerebellar Purkinje cells, and cortical and hippocampal pyramidal neurons. Motility was assayed with time-lapse imaging by using two-photon microscopy of green fluorescent protein-labeled neurons in acute and cultured slices. In all three cell types, dendritic protrusions (filopodia and spines) were highly dynamic, exhibiting a diversity of morphological rearrangements over short (<1-min) time courses. The incidence of spine motility declined during postnatal maturation, but dynamic changes were still apparent in many spines in late-postnatal neurons. Although blockade or induction of neuronal activity did not affect spine motility, disruption of actin polymerization did. We hypothesize that this basal motility of dendritic protrusions is intrinsic to the neuron and underlies the heightened plasticity found in developing CNS.

Detecting action potentials in neuronal populations with calcium imaging

The study of neural circuits requires methods for simultaneously recording the activity of populations of neurons. Here, using calcium imaging of neocortical brain slices we take advantage of the ubiquitous distribution of calcium channels in neurons to develop a method to reconstruct the action potentials occurring in a population of neurons. Combining calcium imaging with whole-cell or perforated patch recordings from neurons loaded with acetoxymethyl ester or potassium salt forms of calcium indicators, we demonstrate that each action potential produces a stereotyped calcium transient in the somata of pyramidal neurons. These signals are detectable without averaging, and the signal-to-noise is sufficient to carry out a reconstruction of the spiking pattern of hundreds of neurons, up to relatively high firing frequencies. This technique could in principle be applied systematically to follow the activity of neuronal populations in vitro and in vivo.

Mechanisms of calcium influx into hippocampal spines: heterogeneity among spines, coincidence detection by NMDA receptors, and optical quantal analysis

Dendritic spines receive most excitatory inputs in the vertebrate brain, but their function is still poorly understood. Using two-photon calcium imaging of CA1 pyramidal neurons in rat hippocampal slices, we investigated the mechanisms by which calcium enters into individual spines in the stratum radiatum. We find three different pathways for calcium influx: high-threshold voltage-sensitive calcium channels, NMDA receptors, and an APV-resistant influx consistent with calcium-permeable AMPA or kainate receptors. These pathways vary among different populations of spines and are engaged under different stimulation conditions, with peak calcium concentrations reaching >10 microM. Furthermore, as a result of the biophysical properties of the NMDA receptor, the calcium dynamics of spines are exquisitely sensitive to the temporal coincidence of the input and output of the neuron. Our results confirm that individual spines are chemical compartments that can perform coincidence detection. Finally, we demonstrate that functional studies and optical quantal analysis of single, identified synapses is feasible in mammalian CNS neurons in brain slices.

Specific interactions of Cu2+ ions with fragments of envelope protein of hepatitis B virus

Potentionmetric and spectroscopic (EPR, CD and absorption spectra) data have shown that a fragment of envelope proteins of the hepatitis B virus could be very specific bind molecules for Cu2+ ions using arginine lateral NH2 donor sites. The presence of Pro and Asp residues makes Arg binding not only very specific, but also very efficient.

Tumor necrosis factor-alpha and basic fibroblast growth factor decrease glial fibrillary acidic protein and its encoding mRNA in astrocyte cultures and glioblastoma cells

Tumor necrosis factor-alpha is a pluripotent cytokine that is reportedly mitogenic to astrocytes. We examined expression of the astrocyte intermediate filament component glial fibrillary acidic protein in astrocyte cultures and the U373 glioblastoma cell line after treatment with tumor necrosis factor-alpha. Treatment with tumor necrosis factor-alpha for 72 h resulted in a decrease in content of glial fibrillary acidic protein and its encoding mRNA. At the same time, tumor necrosis factor-alpha treatment increased the expression of the cytokine interleukin-6 by astrocytes. The decrease in glial fibrillary acidic protein expression was greater when cells were subconfluent than when they were confluent. Thymidine uptake studies demonstrated that U373 cells proliferated in response to tumor necrosis factor-alpha, but primary neonatal astrocytes did not. However, in both U373 cells and primary astrocytes tumor necrosis factor-alpha induced an increase in total cellular protein content. Treatment of astrocytes and U373 cells for 72 h with the mitogenic cytokine basic fibroblast growth factor also induced a decrease in glial fibrillary acidic protein content and an increase in total protein level, demonstrating that this effect is not specific for tumor necrosis factor-alpha. The decrease in content of glial fibrillary acidic protein detected after tumor necrosis factor-alpha treatment is most likely due to dilution by other proteins that are synthesized rapidly in response to cytokine stimulation.

Expression of interleukin-11 and its encoding mRNA by glioblastoma cells

Interleukin-11 (IL-11) is a pleiotropic cytokine with important effects on hematopoietic and other cells. IL-11 was originally described as a product of stromal cell lines and fibroblasts. Using RT-PCR, Northern blotting, and ELISA we demonstrated that the human U373 and U87 glioblastoma cell lines expressed IL-11 and its encoding mRNA when stimulated with IL-1 beta, phorbol ester, and calcium ionophore. The neuroblastoma cell line SH-SY5Y did not express IL-11 mRNA in response to these agents. Cerebral expression of IL-11 by glial cells is important because IL-11 has been shown to have effects on neuronal electrophysiology, has overlapping functions with the neuroactive cytokine interleukin-6, and is part of the gp130-associated neuropoietic family of cytokines.