The organization of frontostriatal brain wiring in non-affective early psychosis compared with healthy subjects using a novel diffusion imaging fiber cluster analysis.

BACKGROUND: Alterations in brain connectivity may underlie neuropsychiatric conditions such as schizophrenia. We here assessed the degree of convergence of frontostriatal fiber projections in 56 young adult healthy controls (HCs) and 108 matched Early Psychosis-Non-Affective patients (EP-NAs) using our novel fiber cluster analysis of whole brain diffusion magnetic resonance imaging tractography. METHODS: Using whole brain tractography and our fiber clustering methodology on harmonized diffusion magnetic resonance imaging data from the Human Connectome Project for Early Psychosis we identified 17 white matter fiber clusters that connect frontal cortex (FCtx) and caudate (Cd) per hemisphere in each group. To quantify the degree of convergence and, hence, topographical relationship of these fiber clusters, we measured the inter-cluster mean distances between the endpoints of the fiber clusters at the level of the FCtx and of the Cd, respectively. RESULTS: We found (1) in both groups, bilaterally, a non-linear relationship, yielding convex curves, between FCtx and Cd distances for FCtx-Cd connecting fiber clusters, driven by a cluster projecting from inferior frontal gyrus; however, in the right hemisphere, the convex curve was more flattened in EP-NAs; (2) that cluster pairs in the right (p = 0.03), but not left (p = 0.13), hemisphere were significantly more convergent in HCs vs EP-NAs; (3) in both groups, bilaterally, similar clusters projected significantly convergently to the Cd; and, (4) a significant group by fiber cluster pair interaction for 2 right hemisphere fiber clusters (numbers 5, 11; p = .00023; p = .00023) originating in selective PFC subregions. CONCLUSIONS: In both groups, we found the FCtx-Cd wiring pattern deviated from a strictly topographic relationship and that similar clusters projected significantly more convergently to the Cd. Interestingly, we also found a significantly more convergent pattern of connectivity in HCs in the right hemisphere and that 2 clusters from PFC subregions in the right hemisphere significantly differed in their pattern of connectivity between groups.

Isotope Shifts of Radium Monofluoride Molecules.

Isotope shifts of ^{223-226,228}Ra^{19}F were measured for different vibrational levels in the electronic transition A^{2}Π_{1/2}←X^{2}Σ^{+}. The observed isotope shifts demonstrate the particularly high sensitivity of radium monofluoride to nuclear size effects, offering a stringent test of models describing the electronic density within the radium nucleus. Ab initio quantum chemical calculations are in excellent agreement with experimental observations. These results highlight some of the unique opportunities that short-lived molecules could offer in nuclear structure and in fundamental symmetry studies.

Spectroscopy of short-lived radioactive molecules.

Molecular spectroscopy offers opportunities for the exploration of the fundamental laws of nature and the search for new particle physics beyond the standard model1-4. Radioactive molecules-in which one or more of the atoms possesses a radioactive nucleus-can contain heavy and deformed nuclei, offering high sensitivity for investigating parity- and time-reversal-violation effects5,6. Radium monofluoride, RaF, is of particular interest because it is predicted to have an electronic structure appropriate for laser cooling6, thus paving the way for its use in high-precision spectroscopic studies. Furthermore, the effects of symmetry-violating nuclear moments are strongly enhanced5,7-9 in molecules containing octupole-deformed radium isotopes10,11. However, the study of RaF has been impeded by the lack of stable isotopes of radium. Here we present an experimental approach to studying short-lived radioactive molecules, which allows us to measure molecules with lifetimes of just tens of milliseconds. Energetically low-lying electronic states were measured for different isotopically pure RaF molecules using collinear resonance ionisation at the ISOLDE ion-beam facility at CERN. Our results provide evidence of the existence of a suitable laser-cooling scheme for these molecules and represent a key step towards high-precision studies in these systems. Our findings will enable further studies of short-lived radioactive molecules for fundamental physics research.

Epidemiology of healthcare associated infections in Germany: Nearly 20 years of surveillance.

OBJECTIVE: To describe the epidemiology of healthcare-associated infections (HAI) in hospitals participating in the German national nosocomial infections surveillance system (KISS). METHOD: The epidemiology of HAI was described for the surveillance components for intensive care units (ITS-KISS), non-ICUs (STATIONS-KISS), very low birth weight infants (NEO-KISS) and surgical site infections (OP-KISS) in the period from 2006 to 2013. In addition, risk factor analyses were performed for the most important infections of ICU-KISS, NEO-KISS and OP-KISS. RESULTS: Data from a total of 3,454,778 ICU patients from 913 ICUs, 618,816 non-ICU patients from 142 non-ICU wards, 53,676 VLBW from 241 neonatal intensive care units (NICU) and 1,005,064 surgical patients from operative departments from 550 hospitals were used for analysis. Compared with baseline data, a significant reduction of primary bloodstream infections (PBSI) and lower respiratory tract infections (LRTI) was observed in ICUs with the maximum effect in year 5 (or longer participation) (incidence rate ratio 0.60 (CI95 0.50-0.72) and 0.61 (CI95 0.52-0.71) respectively). A significant reduction of PBSI and LRTI was also observed in NEO-KISS when comparing the baseline situation with the 5th year of participation (hazard ratio 0.70 (CI95 0.64-0.76) and 0.43 (CI95 0.35-0.52)). The effect was smaller in operative departments after the introduction of OP-KISS (OR 0.80; CI95 0.64-1.02 in year 5 or later for all procedure types combined). Due to the large database, it has not only been possible to confirm well-known risk factors for HAI, but also to identify some new interesting risk factors like seasonal and volume effects. CONCLUSIONS: Participating in a national surveillance system and using surveillance data for internal quality management leads to substantial reduction of HAI. In addition, a surveillance system can identify otherwise not recognized risk factors which should - if possible - be considered for infection control management and for risk adjustment in the benchmarking process.

Diffusion chamber system for testing of collagen-based cell migration barriers for separation of ligament enthesis zones in tissue-engineered ACL constructs.

A temporary barrier separating scaffold zones seeded with different cell types prevents faster growing cells from overgrowing co-cultured cells within the same construct. This barrier should allow sufficient nutrient diffusion through the scaffold. The aim of this study was to test the effect of two variants of collagen-based barriers on macromolecule diffusion, viability, and the spreading efficiency of primary ligament cells on embroidered scaffolds. Two collagen barriers, a thread consisting of a twisted film tape and a sponge, were integrated into embroidered poly(lactic-co-caprolactone) and polypropylene scaffolds, which had the dimension of lapine anterior cruciate ligaments (ACL). A diffusion chamber system was designed and established to monitor nutrient diffusion using fluorescein isothiocyanate-labeled dextran of different molecular weights (20, 40, 150, 500 kDa). Vitality of primary lapine ACL cells was tested at days 7 and 14 after seeding using fluorescein diacetate and ethidium bromide staining. Cell spreading on the scaffold surface was measured using histomorphometry. Nuclei staining of the cross-sectioned scaffolds revealed the penetration of ligament cells through both barrier types. The diffusion chamber was suitable to characterize the diffusivity of dextran molecules through embroidered scaffolds with or without integrated collagen barriers. The diffusion coefficients were generally significantly lower in scaffolds with barriers compared to those without barriers. No significant differences between diffusion coefficients of both barrier types were detected. Both barriers were cyto-compatible and prevented most of the ACL cells from crossing the barrier, whereby the collagen thread was easier to handle and allowed a higher rate of cell spreading.

Selection of resistant acute myeloid leukemia SKM-1 and MOLM-13 cells by vincristine-, mitoxantrone- and lenalidomide-induced upregulation of P-glycoprotein activity and downregulation of CD33 cell surface exposure.

Bone marrow cells and peripheral blood mononuclear cells obtained from both acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) patients contain upregulated levels of cell surface antigen CD33 compared with healthy controls. This difference enables the use of humanized anti-CD33 antibody conjugated to cytotoxic agents for CD33 targeted immunotherapy. However, the expression of the membrane-bound drug transporter P-glycoprotein (P-gp) has been shown to be critical for resistance against the cytotoxicity of a humanized anti-CD33 antibody conjugated to maytansine-derivative DM4. The aim of the present study was to examine whether the expression of P-gp in AML cell lines is associated with changes in CD33 expression. For this purpose, we established drug resistant variants of SKM-1 and MOLM-13 AML cell lines via the selection of parental cells for resistance to vincristine, mitoxantrone and lenalidomide. All three substances induced a multidrug resistance (MDR) phenotype in SKM-1 cells associated with strong upregulation of P-gp and downregulation of CD33. However, in MOLM-13 cells, the upregulation of P-gp and downregulation of CD33 were present only in cells selected for resistance to vincristine and mitoxantrone but not lenalidomide. Inverse expression of P-gp and CD33 were observed in all resistant variants of SKM-1 and MOLM-13 cells. The MDR phenotype of resistant variants of SKM-1 and MOLM-13 cells was associated with alterations in apoptotic regulatory proteins and downregulation of the multidrug resistance associated protein 1 and breast cancer resistance protein.

Regional distribution of nosocomial infections due to ESBL-positive Enterobacteriaceae in Germany: data from the German National Reference Center for the Surveillance of Nosocomial Infections (KISS).

Surveillance systems for hospital infections are reporting increasing rates of extended-spectrum ß-lactamase (ESBL)-positive Enterobacteriaceae in Europe. We aimed to perform a national survey on this trend and on the regional distribution of nosocomial infections due to ESBL-positive Enterobacteriaceae in German hospitals. Data from 2007 to 2012 from two components of the German national nosocomial infection surveillance system were used for this analysis. The data derive from intensive care units and surgical departments. Independent factors determining the proportion of ESBL-positive Enterobacteriaceae among nosocomial infections due to Enterobacteriaceae and changes in its regional distribution (broken down into German federal states) were calculated by regression analysis. From 2007 to 2012, the data showed a significantly increasing proportion of ESBL-positive Enterobacteriaceae in surgical site infections (from 11.46 to 15.38, 134%, p 0.003), urinary tract infections (9.36 to 16.56, 177%, p <0.001) and lower respiratory tract infections (11.91 to 14.70, 123%, p <0.001) due to Enterobacteriaceae. Factors independently associated with a growing proportion were: Thuringia (p 0.009; odds ratio (OR) 1.53), North Rhine-Westphalia (p <0.001; OR 1.41) and general surgery ward (p 0.002; OR 1.47). The proportion of ESBL-positive Enterobacteriaceae in nosocomial infections has significantly increased in Germany over the last 6 years. Hospitals in Central Germany and surgical departments in all of Germany are especially affected by this development.

In vitro characterization of self-assembled anterior cruciate ligament cell spheroids for ligament tissue engineering.

Tissue engineering of an anterior cruciate ligament (ACL) implant with functional enthesis requires site-directed seeding of different cell types on the same scaffold. Therefore, we studied the suitability of self-assembled three-dimensional spheroids generated by lapine ACL ligament fibroblasts for directed scaffold colonization. The spheroids were characterized in vitro during 14 days in static and 7 days in dynamic culture. Size maintenance of self-assembled spheroids, the vitality, the morphology and the expression pattern of the cells were monitored. Additionally, we analyzed the total sulfated glycosaminoglycan, collagen contents and the expression of the ligament components type I collagen, decorin and tenascin C on protein and for COL1A1, DCN and TNMD on gene level in the spheroids. Subsequently, the cell colonization of polylactide-co-caprolactone [P(LA-CL)] and polydioxanone (PDS) polymer scaffolds was assessed in response to a directed, spheroid-based seeding technique. ACL cells were able to self-assemble spheroids and survive over 14 days. The spheroids decreased in size but not in cellularity depending on the culture time and maintained or even increased their differentiation state. The area of P[LA-CL] scaffolds, colonized after 14 days by the cells of one spheroid, was in average 4.57 ± 2.3 mm(2). Scaffolds consisting of the polymer P[LA-CL] were more suitable for colonization by spheroids than PDS embroideries. We conclude that ACL cell spheroids are suitable as site-directed seeding strategy for scaffolds in ACL tissue engineering approaches and recommend the use of freshly assembled spheroids for scaffold colonization, due to their balanced proliferation and differentiation.

Embroidered polymer-collagen hybrid scaffold variants for ligament tissue engineering.

Embroidery techniques and patterns used for scaffold production allow the adaption of biomechanical scaffold properties. The integration of collagen into embroidered polylactide-co-caprolactone [P(LA-CL)] and polydioxanone (PDS) scaffolds could stimulate neo-tissue formation by anterior cruciate ligament (ACL) cells. Therefore, the aim of this study was to test embroidered P(LA-CL) and PDS scaffolds as hybrid scaffolds in combination with collagen hydrogel, sponge or foam for ligament tissue engineering. ACL cells were cultured on embroidered P(LA-CL) and PDS scaffolds without or with collagen supplementation. Cell adherence, vitality, morphology and ECM synthesis were analyzed. Irrespective of thread size, ACL cells seeded on P(LA-CL) scaffolds without collagen adhered and spread over the threads, whereas the cells formed clusters on PDS and larger areas remained cell-free. Using the collagen hydrogel, the scaffold colonization was limited by the gel instability. The collagen sponge layers integrated into the scaffolds were hardly penetrated by the cells. Collagen foams increased scaffold colonization in P(LA-CL) but did not facilitate direct cell-thread contacts in the PDS scaffolds. The results suggest embroidered P(LA-CL) scaffolds as a more promising basis for tissue engineering an ACL substitute than PDS due to superior cell attachment. Supplementation with a collagen foam presents a promising functionalization strategy.

Effect of 9-cis retinoic acid and all-trans retinoic acid in combination with verapamil on P-glycoprotein expression in L1210 cells.

The development of the most common multidrug resistance (MDR) phenotype is associated with a massive overexpression of P-glycoprotein (P-gp) in neoplastic cells. In the current study, we used three L1210 cell variants: S cells - parental drug-sensitive cells; R cells - drug-resistant cells with P-gp overexpression due to selection with vincristine; T cells - drug-resistant cells with P-gp overexpression due to stable transfection with the pHaMDRwt plasmid, which encodes human full-length P-gp. Several authors have described the induction of P-gp expression/activity in malignant cell lines after treatment with all-trans retinoic acid (AtRA; ligand of retinoic acid nuclear receptors, RARs). An isomer of AtRA also exists, 9-cis retinoic acid, which is a ligand of both RARs and nuclear retinoid X receptors (RXRs). In a previous work, we described that the combined treatment of R cells with verapamil and AtRA induces the downregulation of P-gp expression/activity. In the current study, we studied the expression of RARs and RXRs in S, R and T cells and the effects of treatment with AtRA, 9cRA and verapamil on P-gp expression, cellular localization and efflux activity in R and T cells. We found that the overexpression of P-gp in L1210 cells is associated with several changes in the specific transcription of both subgroups of nuclear receptors, RARs and RXRs. We also demonstrated that treatment with AtRA, 9cRA and verapamil induces alterations in P-gp expression in R and T cells. Particularly, combined treatment of R cells with verapamil and AtRA induced downregulation of P-gp content/activity. In contrast, similar treatment of T cells induced slight increase of P-gp content without any changes in efflux activity of this protein. These findings indicate that active crosstalk between the RAR and RXR regulatory pathways and P-gp-mediated MDR could take place.

Metacognition, social cognition, and symptoms in patients with first episode and prolonged psychoses.

While it has been documented that persons with prolonged schizophrenia have deficits in metacognition and social cognition, it is less clear whether these difficulties are already present during a first episode. To explore this issue we assessed and compared metacognition using the Metacognition Assessment Scale-Abbreviated (MAS-A) and social cognition using the Eyes, Hinting and Bell-Lysaker Emotional Recognition Tests (BLERT) in participants with first episode psychosis (FEP; n=26), participants with a prolonged psychosis (n=72), and a psychiatric control group consisting of persons with a substance use disorder and no history of psychosis (n=14). Analyses revealed that both psychosis cohorts scored lower than controls on the MAS-A total and all subscales except metacognitive mastery. Compared to the FEP group, the persons with prolonged psychosis demonstrated greater metacognitive capacities only in those MAS-A domains reflective of the ability to understand the mental state of others and to see that others may have motivations and desires separate from their own. Other domains of metacognition did not differ between psychosis groups. The Eyes, Hinting and BLERT scores of the two psychosis groups did not differ but were poorer than those produced by the control group. Exploratory correlations in the FEP group showed a pattern similar to that previously observed in prolonged psychosis. Taken together, these findings suggest that while certain domains of metacognition could improve with prolonged psychosis, difficulties with global metacognition and social cognition may be stable features of the disorder and perhaps unique to psychosis.

[Healthcare-associated infection rates: measuring and comparing. Experiences from the German National Nosocomial Infection Surveillance System (KISS) and from other surveillance systems]. / Nosokomiale Infektionsraten: Messen und Vergleichen. Erfahrungen mit dem Krankenhaus-Infektions-Surveillance-System (KISS) und anderen Surveillance-Systemen.

Surveillance of nosocomial infections is meanwhile a cornerstone of infection prevention activities in hospitals. The objective of this article is to compare healthcare-associated infection rates in intensive care patients, neonatal intensive care patients and operated patients (ICU-KISS, OP-KISS, NEO-KISS) of the German nosocomial infection surveillance system (KISS) with the corresponding data of the US American National Healthcare Safety Network (NHSN) and the European Centre for Disease Prevention and Control (ECDC). In general, the methodological differences among the three surveillance systems are minor but there are some exceptions. Therefore, differences between countries have to be interpreted very carefully as they may be due to differences in diagnostics, patient mix, types of interventions, length of stay, selection of participating hospitals, post-discharge surveillance activities and interpretation of case definitions. Organizational aspects, such as mandatory participation with public disclosure on infection rates may also have an impact.

Convergent functional genomics of schizophrenia: from comprehensive understanding to genetic risk prediction.

We have used a translational convergent functional genomics (CFG) approach to identify and prioritize genes involved in schizophrenia, by gene-level integration of genome-wide association study data with other genetic and gene expression studies in humans and animal models. Using this polyevidence scoring and pathway analyses, we identify top genes (DISC1, TCF4, MBP, MOBP, NCAM1, NRCAM, NDUFV2, RAB18, as well as ADCYAP1, BDNF, CNR1, COMT, DRD2, DTNBP1, GAD1, GRIA1, GRIN2B, HTR2A, NRG1, RELN, SNAP-25, TNIK), brain development, myelination, cell adhesion, glutamate receptor signaling, G-protein-coupled receptor signaling and cAMP-mediated signaling as key to pathophysiology and as targets for therapeutic intervention. Overall, the data are consistent with a model of disrupted connectivity in schizophrenia, resulting from the effects of neurodevelopmental environmental stress on a background of genetic vulnerability. In addition, we show how the top candidate genes identified by CFG can be used to generate a genetic risk prediction score (GRPS) to aid schizophrenia diagnostics, with predictive ability in independent cohorts. The GRPS also differentiates classic age of onset schizophrenia from early onset and late-onset disease. We also show, in three independent cohorts, two European American and one African American, increasing overlap, reproducibility and consistency of findings from single-nucleotide polymorphisms to genes, then genes prioritized by CFG, and ultimately at the level of biological pathways and mechanisms. Finally, we compared our top candidate genes for schizophrenia from this analysis with top candidate genes for bipolar disorder and anxiety disorders from previous CFG analyses conducted by us, as well as findings from the fields of autism and Alzheimer. Overall, our work maps the genomic and biological landscape for schizophrenia, providing leads towards a better understanding of illness, diagnostics and therapeutics. It also reveals the significant genetic overlap with other major psychiatric disorder domains, suggesting the need for improved nosology.

Influence of laminar airflow on prosthetic joint infections: a systematic review.

BACKGROUND: Many hospitals use ultraclean ventilation (UVC), also known as laminar airflow systems (LAF), in their operating rooms to decrease rates of surgical site infections (SSIs). However, the evidence for these systems is limited and the additional expenses for LAF are substantial. AIM: To determine the effectiveness of LAF to decrease SSI rates following hip and knee prosthesis. METHODS: Systematic review of cohort studies investigating the influence of LAF on SSIs following hip and knee prosthesis published during the last 10 years. FINDINGS: Four cohort studies using the endpoint severe SSI following knee prosthesis and four studies following hip prosthesis were included. No individual study showed a significant benefit for LAF following knee prosthesis but one small study showed a significant benefit following hip prosthesis. However, one individual study showed significantly higher severe SSI rates following knee prosthesis and three studies significantly higher SSI rates following hip prosthesis under LAF conditions. The summary odds ratio was 1.36 (95% confidence interval: 1.06-1.74) for knee prosthesis and 1.71 (1.21-2.41) for hip prosthesis. CONCLUSIONS: It would be a waste of resources to establish new operating rooms with LAF, and questionable as to whether LAF systems in existing operating rooms should be replaced by conventional ventilation systems.

[How many hospital insurance claims are based on infection control failures?]. / Wie häufig kommt es wegen Hygienefehlern zu Anspruchsanmeldungen an die Krankenhäuser?

BACKGROUND AND OBJECTIVE: It can be expected that hospital insurance claims based on health care-associated infections (HCAI) will increase in German hospitals because of growing media and patient interest in this topic. It was the aim of this study to determine the percentage of insurance claims because of HCAI among all potential cases of avoidable HCAI. METHODS: Data of a core group of 254 hospitals continuously working with one of the largest German hospital insurance companies (ECCLESIA) over an eleven-year period were used. The observed number of cases caused by infection control failures (ICF) was compared with the potential number of avoidable HCAI in the entire patient group treated in these hospitals. The type of the failure as well as the probability of an actual ICF were evaluated in each case of ICF by a team of experts. RESULTS: A hospital insurance claim was made in only 0.2 % of all avoidable HCAI cases. Among the 117 cases with payments exceding 700 Euro, only 39 were found to have had a specific infection control problem. Fewer than half of these cases were considered as probable infection control failures by the experts in this field. CONCLUSION: Hospital insurance claims because of HCAI are still rare in German hospitals. In the group of insurance claims because of ICF, some cases had been classified incorrectly.

Prolonged duration of operation: an indicator of complicated surgery or of surgical (mis)management?

PURPOSE: The aim of this study was to investigate whether a prolonged operative time should be regarded as an indicator of quality problems in operating rooms or as patient-specific risk factors when analyzing surgical site infection (SSI) rates. METHOD: Data from the SSI component of the German national nosocomial infection surveillance system (KISS) were used to address this question. Eight procedure categories tracked by at least 30 departments participating in KISS were included in the analysis, namely, hip (2 types) and knee prosthesis, breast surgery, hernia repair, C-section, cholecystectomy and colon operations. Various multiple logistic regression analyses were performed for each procedure category to predict duration of operation. Patient factors (sex, age, American Society of Anesthesiologists score, wound contamination class) and hospital factors (hospital status, size, annual volume) were considered. The area under the receiver operating characteristic (ROC) curve was used to evaluate predictive power including patient- and hospital-based factors. RESULTS: A total of 253,454 operations were included in the analysis. In general, the predictive power of the model including all variables for the different procedure types was relatively low (C-index range: 0.57-0.63) and not much higher than that of the models including only patient-based or only hospital-based variables, respectively. The predictive power for the duration of operative time based on the model including only hospital-based variables was as good as or better than that of the model including only patient-based factors. CONCLUSION: Duration of operation is at least partially determined by hospital factors and, consequently, should be used as a quality indicator to compare SSI infections between hospitals, rather than being used as a patient factor to adjust comparisons between hospitals.

Effect of quercetin on kinetic properties of renal Na,K-ATPase in normotensive and hypertensive rats.

The effect of quercetin, a plant-derived bioflavonoid with documented positive effect on the cardiovascular system, was examined after 4-week supplementation in the dose of 20 mg kg(-1) x day(-1) to young male normotensive control (C) and to spontaneously hypertensive rats (SHR) over the period of their 5(th)-8(th) week of age. The study was focused on the influence of quercetin on properties of the renal Na,K-ATPase, a key system in maintaining the homeostasis of sodium in the organism. Spontaneous hypertension by itself enhanced the activity of Na,K-ATPase probably as a consequence of a higher number of active enzyme molecules, as suggested by the 15% increase of V(max), along with improved affinity to ATP, as indicated by the 30% decrease in the value of Michaelis-Menten constant K(m) in untreated SHR vs. untreated normotensive rats. Quercetin induced a decrease of Na,K-ATPase activity in the presence of all ATP and Na(+) concentrations investigated. Evaluation of kinetic parameters resulted in a constant V(max) value. The ATP-binding properties of the enzyme were not influenced by quercetin, as suggested by statistically insignificant changes in the value of K(m) both in controls and in SHR. On the other hand, the affinity to sodium decreased, as suggested by an increase in the K(Na) value by 22% and 31% in normotensive and hypertensive groups, respectively. This impairment in the affinity of the Na(+)-binding site of Na,K-ATPase molecules was probably responsible for the deteriorated enzyme function in the kidneys of quercetin treated animals.

Overexpression of P-glycoprotein in L1210/VCR cells is associated with changes in several endoplasmic reticulum proteins that may be partially responsible for the lack of thapsigargin sensitivity.

L1210/VCR cells, which express an abundant amount of P-glycoprotein (P-gp), were found to be resistant to thapsigargin--an inhibitor of sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPase (SERCA). In the current paper, we have studied the possible differences among L1210 and L1210/VCR cells in expression of endoplasmic reticulum proteins involved in the regulation of calcium homeostasis and calcium-dependent processes. Amounts of mRNA encoding both calcium release channels (ryanodine receptor channels--RyR and IP3-receptor channels--IP3R) were found to be at similar levels in sensitive and resistant cells. However, mRNAs encoding IP3R1 or 2 were decreased in resistant cells cultivated in the presence of VCR (1.08 micromol/l), while mRNA encoding RyR remained unchanged. The amount of mRNA for SERCA2 was decreased in resistant cells when compared with sensitive cells. This decrease was more pronounced when resistant cells were cultivated in the presence of vincristine (VCR). Calnexin was found to be less expressed at the protein level in resistant as in sensitive cells. The level of mRNA encoding calnexin was decreased only when resistant cells were cultivated in the presence of VCR. Calnexin was found to be associated with immature P-gp in resistant cells. Thus, differences exist between sensitive and resistant cells in the expression of endoplasmic reticulum proteins involved in the control of intracellular calcium homeostasis or calcium-dependent processes. These changes may be at least partially responsible for the lack of sensitivity of resistant cells to thapsigargin.

Modulation of expression of Na+/Ca2+ exchanger in heart of rat and mouse under stress.

AIM: The Na(+)/Ca(2+) exchanger (NCX) is a major Ca(2+) extrusion system in the plasma membrane of cardiomyocytes and an important component participating on the excitation-contraction coupling process in muscle cells. NCX1 isoform is the most abundant in the heart and is known to be changed after development of ischaemia or myocardial infarction. Objective of this study was to investigate the effect of stress factors (immobilization, cold and short-term hypoxia) on the expression of NCX1, in vivo, in the heart of rat and mouse. METHODS: We compared gene expression and protein levels of control and stressed animals. The activity of NCX was measured by the whole cell configuration using the patch clamp. We also measured physiological parameters of the heart in physiological conditions and under ischaemia-reperfusion to compare response of control and stressed hearts. RESULTS: We have found that only strong stress stimulus (hypoxia, immobilization) applied repeatedly for several days elevated the NCX1 mRNA level. Cold, which is a weaker stressor that activates mainly sympathoneural, and only marginally adrenomedullary system did not affect the gene expression of NCX1. Thus, from these results it appears that hormones produced by the adrenal medulla (mainly adrenaline) might be involved in this process. To study possible mechanism of the NCX1 regulation by stress, we focused on the possible role of the hypothalamo-pituitary-adrenocortical pathway in the activation of catecholamine synthesis in the adrenal medulla. We have already published that cortisol affects activity, but not the gene expression of NCX1. In this work, we used corticotropin-releasing hormone (CRH) knockout mice, where secretion of corticosterone and subsequently adrenaline is significantly suppressed. As no increase in NCX1 mRNA was observed in CRH knockout mice due to immobilization stress, we proposed that adrenaline (probably regulated via corticosterone) is involved in the regulation of NCX1 gene expression during stress. CONCLUSIONS: The gene expression and protein levels of the NCX1 are increased by the strong stress stimuli, e.g. hypoxia, or immobilization stress. The activity of NCX1 is decreased. Based on these results, we assume that the gene expression of NCX is increased as a consequence of suppressed activity of this transport system.

Structural differences between sensitive and resistant L1210 cells.

The main structural differences between sensitive L1210 mouse leukaemic cells and their multidrug resistant counterpart, obtained by adaptation of the parental cell line to vincristine (VCR), concern the size and shape of the cells, their surface properties and changes in organelles involved in proteosynthesis and transport of substances. The resistant cells are larger with higher density of microvilli. In light and electron micrographs containing a group of cells, cells were found to be closer to each other in L1210/VCR cells than in L1210 cells. This difference in cell aggregation suggests different surface properties which could be visualised by decreased staining of L1210/VCR cell surface coat (glycocalyx) with a polycationic dye ruthenium red. A decrease in surface to volume ratio as a consequence of increased cell size in resistant cells is compensated by proliferation of villi and cytoplasmic protrusions of the cell surface. L1210/VCR cells were further distinguished by higher amount of euchromatin, increase in density of rough endoplasmic reticulum, more developed Golgi apparatus and aggregation of free ribosomes into tetrameric and pentameric polyribosomes. These structural changes may be interpreted as a sign of increase in proteosynthesis and transport of substances.