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Ecosystem nitrogen (N), phosphorus (P), and calcium (Ca) fluxes are affected by inputs of atmospheric N. Oak litter may additionally affect these fluxes because of its high-lignin content. We analyzed nutrient dynamics in ambient mixed-species litter in an aggrading hardwood stand at the Fernow Experimental Forest in West Virginia. We separated oak from the mix for analysis (oak) and compared it with total litter (all species) to understand how oak affects nutrient fluxes in the litter layer. The study was conducted under ambient atmospheric deposition, under elevated atmospheric deposition, and under elevated deposition plus mitigation with dolomite. N flux between litterfall and 12 months later indicated a net loss in all-species litter of up to 7.3 kg N·ha–1 and a retention of up to 0.6 kg N·ha–1 in oak. P flux included losses in all species in ambient and in dolomite treatments of up to 0.19 kg P·ha–1 and gains of up to 0.12 kg P·ha–1 in oak in all treatments. Oak mineralized Ca at an average across treatments of 4.6 kg Ca·ha–1 compared with 16 kg Ca·ha–1 in all species, with half of that when trees were dormant. Percent immobilization and release over initial litter were greater in oak than in all species, but nutrient fluxes were lower in oak than in all species because of low oak litter mass. Elevated deposition lowered N and increased P immobilization. Dolomite appeared to affect early N dynamics only. With an increase in litterfall mass when forests mature, these effects are also likely to increase. [ABSTRACT FROM AUTHOR]

We analyzed spatial and temporal dynamics of solute chemistry in a forest watershed impacted by atmospheric deposition in the Adirondack Mountains of New York State, USA. Spatial dynamics of solute chemistry and natural abundance isotopes of nitrate (15N and 18O) were examined in 6 locations and the watershed outlet in 2001 and 2002. Temporal dynamics were examined during 5 discharge periods: winter, snowmelt, spring, summer, and fall, which were based on discharge levels at the outlet. Solute concentrations were statistically significantly different (p≤0.05) among stream sampling locations and discharge periods, with no interaction effects. Groundwater sources located in upper watershed controlled stream chemistry at higher elevations with highest pH, Ca2+, sum of base cations, Si, NO-3 , total N, and SO2- 4 and lowest Al concentrations. Two low elevation wetlands had a substantial influence over stream chemistry at those locations contributing lowest NO-3 , total N, and highest DOC and DON. Snowmelt exhibited among the lowest pH, sum of base cations, and SO2- 4 , and highest NO-3 , total N, DON, and total Al; snowmelt appeared to dilute groundwater, and flush stored soil-derived solutes. Summer discharge, composed mainly of groundwater, exhibited the lowest flow, among the highest Mg2+, Ca2+, and lowest DON, DOC, and total Al concentrations. Isotopic analysis together with patterns of NH+4 versus NO-3 dynamics indicated that NO-3 was microbial, generated in fall and accumulated in winter in upper watershed soils, and flushed to stream during high discharge events. Highest discharge in snowmelt 2001, a summer drought in 2002, and fall storms following the drought were further evaluated for their specific effects on stream chemistry. Snowmelt 2001 had the lowest pH and highest NO-3 , base flow during summer drought had the lowest total Al, and storms in fall 2002 had highest SO2- 4 of all periods, but all other solute concentrations were comparable to other discharge periods in this study. Depending on objectives, watershed outlet alone may sufficiently represent solute dynamics in the watershed, and high-discharge events may sufficiently describe solute fluxes for the watershed. [ABSTRACT FROM AUTHOR]

Introduction: The prostaglandin E 2 (PGE 2 ) pathway is one of the main mediators of intestinal inflammation. As activation of the calcium-sensing receptor (CaSR) induces expression of inflammatory markers in the colon, we assessed the impact of the CaSR on the PGE 2 pathway regulation in colon cancer cells and the colon in vitro and in vivo . Methods and Results: We treated CaSR-transfected HT29 and Caco-2 colon cancer cell lines with different orthosteric ligands or modulators of the CaSR and measured gene expression and PGE 2 levels. In CaSR-transfected HT29 CaSR-GFP and Caco-2 CaSR-GFP cells, the orthosteric CaSR ligand spermine and the positive allosteric CaSR modulator NPS R -568 both induced an inflammatory state as measured by IL-8 gene expression and significantly increased the expression of the PGE 2 pathway key enzymes cyclooxygenase (COX)-2 and/or prostaglandin E 2 synthase 1 (PGES-1). Inhibition of the CaSR with the calcilytic NPS 2143 abolished the spermine- and NPS R -568-induced pro-inflammatory response. Interestingly, we observed cell-line specific responses as e.g . PGES-1 expression was affected only in HT29 CaSR-GFP but not in Caco-2 CaSR-GFP cells. Other genes involved in the PGE 2 pathway (COX-1, or the PGE 2 receptors) were not responsive to the treatment. None of the studied genes were affected by any CaSR agonist in GFP-only transfected HT29 GFP and Caco-2 GFP cells, indicating that the observed gene-inducing effects of spermine and R -568 were indeed mediated by the CaSR. In vivo , we had previously determined that treatment with the clinically approved calcimimetic cinacalcet worsened symptoms in a dextran sulfate sodium (DSS)-induced colitis mouse model. In the colons of these mice, cinacalcet significantly induced gene expression of PGES-2 and the EP3 receptor, but not COX-2; while NPS 2143 increased the expression of the PGE 2 -degrading enzyme 15-hydroxyprostaglandin dehydrogenase (15-PGDH). Importantly, neither treatment had any effect on the colons of non-DSS treated mice. Discussion: Overall, we show that activation of the CaSR induces the PGE 2 pathway, albeit with differing effects in vitro and in vivo . This may be due to the different microenvironment in vivo compared to in vitro , specifically the presence of a CaSR-responsive immune system. Since calcilytics inhibit ligand-mediated CaSR signaling, they may be considered for novel therapies against inflammatory bowel disease., Competing Interests: Author LI is employed by SiSaf Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Gushchina, Kupper, Schwarzkopf, Frisch, Piatek, Aigner, Michel, Schueffl, Iamartino, Elajnaf, Manhardt, Vlasaty, Heffeter, Bassetto, Kállay and Schepelmann.)

Aims: Heart failure with preserved ejection fraction (HFpEF) is one of the most rapidly growing cardiovascular health burden worldwide, but there is still a lack of understanding about the HFpEF pathophysiology. The nitric oxide (NO) signalling pathway has been identified as a potential key element. The aim of our study was to investigate markers of NO metabolism [l-arginine (l-Arg), homoarginine (hArg), and asymmetric and symmetric dimethylarginine (ADMA and SDMA)], additional biomarkers [N-terminal pro-B-type natriuretic peptide (NT-proBNP), endothelin-1 (ET-1), mid-regional pro-adrenomedullin (MR-proADM), copeptin, and high-sensitivity C-reactive protein (hsCRP)], and the endothelial function in an integrated approach focusing on associations with clinical characteristics in patients with HFpEF., Methods and Results: Seventy-three patients, prospectively enrolled in the 'German HFpEF Registry', were analysed. Inclusion criteria were left ventricular ejection fraction (LVEF) ≥ 50%; New York Heart Association functional class ≥ II; elevated levels of NT-proBNP > 125 pg/mL; and at least one additional criterion for structural heart disease or diastolic dysfunction. All patients underwent transthoracic echocardiography, cardiopulmonary exercise testing, and pulse amplitude tonometry (EndoPAT™). Patients were categorized in two groups based on their retrospectively calculated HFA-PEFF score. Serum concentrations of l-Arg, hArg, ADMA, SDMA, NT-proBNP, ET-1, MR-proADM, copeptin, and hsCRP were determined. Patients had a median age of 74 years, 47% were female, and median LVEF was 57%. Fifty-two patients (71%) had an HFA-PEFF score ≥ 5 (definitive HFpEF), and 21 patients (29%) a score of 3 to 4 (risk for HFpEF). Overall biomarker concentrations were 126 ± 32 μmol/L for l-Arg, 1.67 ± 0.55 μmol/L for hArg, 0.74 (0.60;0.85) μmol/L for SDMA, and 0.61 ± 0.10 μmol/L for ADMA. The median reactive hyperaemia index (RHI) was 1.55 (1.38;1.87). SDMA correlated with NT-proBNP (r = 0.291; P = 0.013), ET-1 (r = 0.233; P = 0.047), and copeptin (r = 0.381; P = 0.001). ADMA correlated with ET-1 (r = 0.250; P = 0.033) and hsCRP (r = 0.303; P = 0.009). SDMA was associated with the left atrial volume index (β = 0.332; P = 0.004), also after adjustment for age, sex, and comorbidities. Biomarkers were non-associated with the RHI. A principal component analysis revealed two contrary clusters of biomarkers., Conclusions: Our findings suggest an impaired NO metabolism as one possible key pathogenic determinant in at least a subgroup of patients with HFpEF. We argue for further evaluation of NO-based therapies. Upcoming studies should clarify whether subgroups of HFpEF patients can take more benefit from therapies that are targeting NO metabolism and pathway., (© 2022 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Ovarian cancer is one of the deadliest cancers in women, due to its heterogeneity and usually late diagnosis. The current first-line therapies of debulking surgery and intensive chemotherapy cause debilitating side effects. Therefore, there is an unmet medical need to find new and effective therapies with fewer side effects, or adjuvant therapies, which could reduce the necessary doses of chemotherapeutics. Vitamin D is one of the main regulators of serum calcium and phosphorus homeostasis, but it has also anticancer effects. It induces differentiation and apoptosis, reduces proliferation and metastatic potential of cancer cells. However, doses that would be effective against cancer cause hypercalcemia. For this reason, synthetic and less calcemic analogs have been developed and tested in terms of their anticancer effect. The anticancer role of vitamin D is best understood in colorectal, breast, and prostate cancer and much less research has been done in ovarian cancer. In this review, we thus summarize the studies on the role of vitamin D and its analogs in vitro and in vivo in ovarian cancer models.

Colitis is a major risk factor for the development of colorectal cancer, leading to colitis-associated colorectal cancer (CAC). The most commonly used animal model to study CAC is the azoxymethane-dextran sulphate-sodium (AOM/DSS) model. The ideal experimental conditions of this model depend on several factors, including the used mouse strain. No data on feasibility and conditions for older mice, e.g., for aging studies, have yet been reported. Thus, we conducted a descriptive, observational pilot study where CAC was induced in 14-month-old female Balb/C and C57/Bl6 mice using 12.5 mg/kg AOM i.p. and three different concentrations of DSS (1, 2, and 3%) in drinking water (ad. lib.). The mice were monitored regularly during the three-month experimental phase. After euthanasia, the colons of the mice were evaluated macroscopically and microscopically. Both the mouse strains showed a DSS-concentration-dependent induction of CAC. Carcinomas were only observed at 3% DSS. The DSS dose was found to be significantly correlated with the histology score and % Ki67 positive cells only in C57/Bl6 mice but not in Balb/C mice, which showed a variable response to the CAC induction. No differences in colon length, weight, or mucin content were observed. Optimal conditions for CAC induction in these aged animals are thus considered to be 3% DSS, as carcinomas did not develop when 2% DSS was used. On the other hand, Balb/C mice reacted severely to 3% DSS, indicating that 2.5% DSS may be the "sweet spot" for future experiments comparing CAC in aged Balb/C and C57/Bl6 mice. This model will allow investigation of the effect of aging on CAC development and therapy.

Background: Ovarian cancer (OC) is one of the most lethal cancers in women. The active form of vitamin D 3 , 1,25-dihydroxyvitamin D 3 (1,25D 3 , calcitriol) has anticancer activity in several cancers, including ovarian cancer, but the required pharmacological doses may cause hypercalcemia. We hypothesized that newly developed, low calcemic, vitamin D analogs (an1,25Ds) may be used as anticancer agents instead of calcitriol in ovarian cancer cells., Methods: We used two patient-derived high-grade serous ovarian cancer (HGSOC) cell lines with low (13781) and high (14433) mRNA expression levels of the gene encoding 1,25-dihydroxyvitamin D 3 24-hydroxylase CYP24A1 , one of the main target genes of calcitriol. We tested the effect of calcitriol and four structurally related series of an1,25Ds (PRI-1906, PRI-1907, PRI-5201, PRI-5202) on cell number, viability, the expression of CYP24A1 , and the vitamin D receptor (VDR)., Results: CYP24A1 mRNA expression increased in a concentration-dependent manner after treatment with all compounds. In both cell lines, after 4 h, PRI-5202 was the most potent analog (in 13781 cells: EC 50 = 2.98 ± 1.10 nmol/L, in 14433 cells: EC 50 = 0.92 ± 0.20 nmol/L), while PRI-1907 was the least active one (in 13781 cells: EC 50 = n/d, in 14433 cells: EC 50 = n/d). This difference among the analogs disappeared after 5 days of treatment. The 13781 cells were more sensitive to the an1,25Ds compared with 14433 cells. The an1,25Ds increased nuclear VDR levels and reduced cell viability, but only in the 13781 cell line., Conclusions: The an1,25Ds had different potencies in the HGSOC cell lines and their efficacy in increasing CYP24A1 expression was cell line- and chemical structure-dependent. Therefore, choosing sensitive cancer cell lines and further optimization of the analogs' structure might lead to new treatment options against ovarian cancer.

Pharmacological allosteric agonists (calcimimetics) of the extracellular calcium-sensing receptor (CaSR) have substantial gastro-intestinal side effects and induce the expression of inflammatory markers in colon cancer cells. Here, we compared the effects of both CaSR-specific ( R enantiomers) and -unspecific ( S enantiomers) enantiomers of a calcimimetic (NPS 568) and a calcilytic (allosteric CaSR antagonists; NPS 2143) to prove that these effects are indeed mediated via the CaSR, rather than via off-target effects, e.g., on β-adrenoceptors or calcium channels, of these drugs. The unspecific S enantiomer of NPS 2143 and NPS S- 2143 was prepared using synthetic chemistry and characterized using crystallography. NPS S -2143 was then tested in HEK-293 cells stably transfected with the human CaSR (HEK-CaSR), where it did not inhibit CaSR-mediated intracellular Ca 2+ signals, as expected. HT29 colon cancer cells transfected with the CaSR were treated with both enantiomers of NPS 568 and NPS 2143 alone or in combination, and the expression of CaSR and the pro-inflammatory cytokine interleukin 8 (IL-8) was measured by RT-qPCR and ELISA. Only the CaSR-selective enantiomers of the calcimimetic NPS 568 and NPS 2143 were able to modulate CaSR and IL-8 expression. We proved that pro-inflammatory effects in colon cancer cells are indeed mediated through CaSR activation. The non-CaSR selective enantiomer NPS S- 2143 will be a valuable tool for investigations in CaSR-mediated processes.

Objectives: Intrahepatic cholestasis in pregnancy (ICP) is a pregnancy-specific liver disorder. Its etiology is not fully understood. Increasing evidence indicates the important role of vitamin D and the vitamin D receptor (VDR) in this disorder. The presence of polymorphic variants in the VDR gene could influence its activity and susceptibility to ICP development. The goal of the study was to investigate the role of four genetic polymorphisms of the VDR gene - Fok (rs731236), Bsm (rs1544410), Apa (rs7975232), and Taq (rs731236) - in the etiology of ICP in Polish women., Material and Methods: Ninety-eight women with confirmed ICP and 215 healthy pregnant women as a control group were recruited to the study. We examined four SNPs of the VDR gene: BsmI (rs7975232), TaqI (rs1544410), ApaI (rs228570), FokI (rs731236). Genotyping was performed using the PCR/RFLP method., Results: We observed higher frequency (borderline significant) of the Ff-ff genotypes containing at least one mutated allele of the VDR FokI polymorphism in the control group compared to the ICP group (p = 0.045, OR = 1.71, 95% CI 1.01-2.88). The frequency of the mutated f allele was slightly higher in controls (49.1%) than in the ICP group (43.4%) (OR = 1.26, 95% CI 0.90-1.77), but the difference was not statistically significant (p = 0.196)., Conclusions: Our results showed that the maternal VDR FokI polymorphism could play a protective role in ICP development and probably modulate the risk of ICP occurrence in pregnant women in the Polish population. In the future, to confirm these observations, research in larger, ethnically stratified and clinically analyzed groups is necessary.

Aims: The aim of this study was to assess the spatial relationship of blood vessels and the thickness of the atrial wall within the mitral isthmus line., Methods and Results: A total of 200 randomly selected autopsied adult human hearts (Caucasian) were examined. The mitral isthmus line was cut longitudinally and the thickness of the left atrial wall was measured. The blood vessels within the isthmus were identified and their relationship with the endocardial surface (ES), mitral annulus (MA), and the left inferior pulmonary vein (LIPV) ostium was assessed. The mean myocardial thickness in the upper, middle, and lower 1/3 of the mitral isthmus section were 1.9 ± 1.0, 3.0 ± 1.5, and 2.7 ± 1.3 mm, respectively. The great cardiac vein (GCV) was present within the isthmus in 98.0%, the left circumflex artery (LCx) in 57.0%, and the Marshall vein in 35.0% of all hearts. The GCV was located 4.5 ± 2.2 mm from the ES, 7.3 ± 5.3 mm from the MA, and 24.3 ± 7.3 mm from the LIPV. The LCx was situated 3.8 ± 2.3 mm from the ES, 7.9 ± 5.1 mm from the MA, and 25.3 ± 8.0 mm from the LIPV. We were able to detect eight different patterns of GCV and LCx mutual arrangement within the mitral isthmus line., Conclusion: The myocardium is the thinnest in the upper 1/3 sector, and the blood vessels are mainly located in the middle and lower 1/3. In 49.1%, the LCx is situated at a distance of less than 3 mm from the ES. In 55.3%, the LCx is located between the GCV and ES of the left atrium.

Background/aim: One of the current hypotheses assumes that brain tumors exert an immunosuppressive influence on the surrounding cellular environment. Interleukin-10 (IL-10) is one of the immunosuppressive cytokines modifying the biological activity of cancer. The aim of this study was to assess the expression of IL10R in CD45 + cells within primary brain tumors and metastases and establish its association with tumor basic immunophenotype., Patients and Methods: Tissue samples were obtained intraoperatively during surgeries of 32 patients suffering from meningiomas (n=9), gliomas (n=12) and metastatic tumors (n=11). Expression was assessed with flow cytometry and immunohistochemical reactions., Results: Expression of IL10R subunits within the leukocyte population (CD45 + cells) was significantly higher in primary tumors than in metastases., Conclusion: To the best of our knowledge, this is the first study describing a correlation between the IL10R expression on leukocytes and histological types of brain tumors., (Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Persistent left superior vena cava (PLSVC) is the most common congenital malformation of thoracic venous return and is present in 0.3 to 0.5% of individuals in the general population. This heart specimen was dissected from a 35-year-old male cadaver whose cause of death was determined as non-cardiac. The heart was examined and we found a PLSVC draining into the coronary sinus. The right superior vena cava was present with a small-diameter ostium. An anomalous pulmonary vein pattern was observed; there was a common trunk to the left superior and left inferior pulmonary veins (diameter 17.8 mm) and an additional middle right pulmonary vein (diameter 2.7 mm) with two classic right pulmonary veins. The PLSVC draining into the coronary sinus had led to its enlargement, which could have altered the cardiac haemodynamics by significantly reducing the size of the left atrium and impeding its outflow via the mitral valve.

Purpose: Human thyroid development is a complex and still unexplained process. Thyroid hemiagenesis is a congenital anomaly, where one of the thyroid lobes fails to develop. In the majority of patients with thyroid hemiagenesis, the genetic background remains unknown. The aim of the study was to search for novel genetic contributors to the etiology of thyroid hemiagenesis., Methods: A cohort of 34 sporadic patients diagnosed with thyroid hemiagenesis and one three-generation family were subjected to comprehensive genomic examination. Initially, targeted screening of associated transcription factors, known to be linked to thyroid development, was performed. As a next step, genomic examinations were applied using high-resolution microarrays, whereas for the thyroid hemiagenesis family, additionally the whole exome sequencing was performed., Results: Screening of transcription factors revealed no causative mutations in the studied cohort. Genomic examinations revealed the presence of four recurrent defects (three deletions and one duplication) affecting highly conservative proteasome genes PSMA1, PSMA3, and PSMD3. In a thyroid hemiagenesis family a splice site mutation in a proteasome gene PSMD2 (c.612T > C cDNA.1170T > C, g.3271T > C) was found in both affected mother and daughter., Conclusions: Our results shed a new light on etiology of thyroid hemiagenesis, so far suspected to be linked only to mutations in the genes directly involved in the thyroid development. We demonstrated, for the first time, that genomic alterations in proteasome-associated genes co-occur in patients presenting this developmental anomaly.

Aims: The first aim of this study was to determine the size of the Koch's triangle. The second one was to investigate relation between its dimensions and other individual-specific and heart-specific parameters as well as to create universal formula to estimate triangle dimensions based on these parameters., Methods and Results: This study is a prospective one, presenting 120 randomly selected autopsied hearts dissected from adult humans (Caucasian) of both sexes (31.7% females), with mean age of 49.3 ± 17.4 years. The length of triangle sides and angles were measured and the triangle area was calculated as well. Sixteen additional heart parameters were measured in order to analyse potential relationship between the dimensions of Koch's triangle and other dimensions of the heart, using linear regression analysis. The mean (±SD) length of the anterior edge was approximated to 18.0 ± 3.8 mm, the posterior edge to 20.3 ± 4.3 mm, and the basal edge to 18.5 ± 4.0 mm. The average values of the apex angle, the Eustachian angle, and the septal leaflet angle were 58.0 ± 14.4°, 53.8 ± 10.6°, and 67.6 ± 14.4°, respectively. The mean value of the Koch's triangle area was 151.5 ± 55.8 mm2. The 95th percentile of triangle's height (the distance from the apex to the coronary sinus) was 21.8 mm., Conclusion: Mean values and proportions of triangle's sides and angles were presented. Koch's triangle showed considerable individual variations in size. The dimensions of the triangle were strongly independent from individual-specific and heart-specific morphometric parameters; however, the maximum triangle's height can be estimated as 22 mm., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2016. For permissions please email: journals.permissions@oup.com.)

The colonisation of land by plants may not have been possible without mycorrhizae, which supply the majority of land plants with nutrients, water and other benefits. In this sense, the mycorrhization of basal groups of land plants such as ferns and lycophytes is of particular interest, yet only about 9% of fern and lycophyte species have been sampled for their mycorrhization status, and no community-level analyses exist for tropical fern communities. In the present study, we screened 170 specimens of ferns and lycophytes from Malaysia and Sulawesi (Indonesia), representing 126 species, and report the mycorrhization status for 109 species and 19 genera for the first time. Mycorrhizal colonisations were detected in 96 (56.5%) of the specimens, 85 of which corresponded to arbuscular mycorrhizae (AMF), three to dark-septate endophytes (DSE) and four to mixed colonisations (AMF + DSE). DSE colonisations were lower than in comparable samples of ferns from the Andes, suggesting a geographical or taxonomic pattern in this type of colonisation. Epiphytes had significantly lower levels of colonisation (26.1%) than terrestrial plants (70.7%), probably due to the difficulty of establishment of mycorrhizal fungi in the canopy habitat.

A case of a 64-year-old male with multiple cardiovascular disease risk factors and non-ST segment elevation myocardial infarction complicated by recurrent stent thrombosis is presented. Percutaneous coronary angioplasty with bare metal stent implantation was performed due to critical stenosis of the left circumflex coronary artery. The recovery was complicated by two episodes of stent thrombosis on the 4th and 10th day of in-hospital stay, both treated by subsequent percutaneous coronary interventions. Our hypothesis of resistance to antiplatelet therapy was confirmed by an in vitro test.

Using fluorescence and UV-vis spectroscopies and mass spectrometry, we demonstrated that the presence of physiological levels of reduced glutathione enhances the binding of Zn(II) to XPAzf, a Cys4 zinc finger peptide derived from the XPA protein, by means of formation of a ternary complex of a general formula ZnXPAzf[GSH]. Similar complexes were also indicated by ESI-MS for isostructural Co(II)- and Cd(II)-substituted XPAzf. The observed enhancement of the Zn(II) binding to XPAzf by a factor of 50 over the physiological range of GSH concentrations of 1-20 mM corresponds to a dissociation constant of GSH from the ZnXPAzf[GSH] complex of 0.05 microM. This effect may account for an apparent discrepancy between relatively low Zn(II) binding constants measured in vitro for many zinc fingers, and the requirement of tight Zn(II) binding enforced by intracellular zinc buffering by the thionein/metallothionein couple.

The accumulation of 8-hydroxy-2'-deoxyguanosine (8-OH-dG) exemplifies oxidative DNA injury, which is strongly implicated in ageing. We show that human peritoneal mesothelial cells (HPMCs) from donors >75 years have lower proliferative capacity but increased 8-OH-dG content compared with cells from individuals <25 years. We detected a positive relationship between the donor's age and the 8-OH-dG level in early-passage HPMCs, and an inverse relationship between those 8-OH-dG levels and subsequent replicative lifespan of HPMCs (n=30). In early-passage cells from donors >75 years, the repair of oxidant-induced 8-OH-dG was delayed compared to cells from donors <25 years. This was coupled with prolonged removal of reactive oxygen species and faster decline in superoxide dismutase activity. Similar effects were observed in HPMCs rendered senescent in vitro. These results indicate that increased 8-OH-dG levels in HPMCs from aged individuals may reflect the in vivo presence of senescent cells with increased vulnerability to oxidative stress-induced DNA damage.

Arsenic compounds are human carcinogens. The ingested inorganic arsenic is metabolized to methylated derivatives, which are considered to be more toxic than the inorganic species. Interactions of trivalent arsenicals with thiol groups of proteins are believed to be important for arsenic carcinogenesis, but inorganic arsenite appears to bind to thiol groups more strongly than the methylated As (III) species. Inhibition of the nucleotide excision repair pathway of DNA repair (NER) is likely to be of primary importance in arsenic carcinogenesis. Previously, we demonstrated that methylated As (III) compounds are more efficient than arsenite in releasing zinc from ZnXPAzf, the zinc finger of XPA, a crucial member of the NER complex [Schwerdtle, T., Walter, I., and Hartwig, A. (2003) Arsenite and its biomethylated metabolites interfere with the formation and repair of stable BPDE-induced DNA adducts in human cells and impair XPAzf and Fpg. DNA Repair (Amsterdam) 2, 1449-1463]. In this work, we used ESI-MS to compare aerobic reactivities of arsenite and monomethylarsonous acid (MMA (III)) toward ZnXPAzf on the molecular level. We demonstrated that equimolar MMA (III) released Zn (II) from ZnXPAzf easily, forming mono- and diarsenical derivatives of XPAzf. This reaction was accompanied by oxidation of unprotected thiol groups of the monomethylarsinated peptide to intramolecular disulfides. The estimated affinity of MMA (III) to XPAzf is 30-fold higher than that established previously for arsenite binding to the thiol groups. No binding of arsenite to the thiol groups of XPAzf was observed under our experimental conditions, and a 10-fold excess of arsenite was required to partially oxidize ZnXPAzf. These results indicate a particular susceptibility of tetrathiolate zinc fingers to MMA (III), thereby providing a novel molecular pathway in arsenic carcinogenesis.

In Escherichia coli, heterologous production of Schizosaccharomyces pombe phytochelatin synthase (PCS) along with overproduction of E. coli serine acetyltransferase (SAT) and gamma-glutamylcysteine synthase (gammaECS) was achieved and resulted in the accumulation of phytochelatins in bacterial cells. Overproduction of either gammaECS alone or simultaneous production of all three proteins in bacterial cells were accompanied by reduced growth rate in liquid cultures. Interestingly, bacteria overproducing either gammaECS or both SAT and gammaECS (with elevated level of gamma-glutamylcysteine but not of phytochelatins) were able to accumulate more cadmium per dry weight than the control. However, the most efficient cadmium accumulation was observed in bacteria with elevated levels of all three proteins: SAT, gammaECS and PCS. Therefore, "pushing" the entire pathway might be the most promising approach in modification of bacteria for potential bioremediation purposes because the level of intermediates, cysteine and glutathione, can limit the rate of production of phytochelatins. However, in such bacteria other metabolic process might become limiting for efficient growth.

Unpleasant somatic and perceptual side effects can be induced when viewing striped repetitive patterns, such as a square wave or a page of text. This sensitivity is greater in participants with higher scores on a scale of visual discomfort. In three experiments the effect that this sensitivity has on performance efficiency in a reading-like visual search task was investigated. In experiments 1 and 2, the 'global' structure of the patterns was manipulated to produce a square-wave, a checkerboard, and a plaid pattern. It was found that the group that suffered severe visual discomfort took significantly longer than other groups to perform the task, with interference greatest with presentation of the square-wave-like pattern. This supports the prediction of greatest distraction of visual attention from the local target elements with presentation of the pattern structure inducing greatest visual discomfort. In experiment 3, the internal pattern components were manipulated and task difficulty reduced. A no-interference and two interference patterns, one with a global characteristic only and the second made up of distracting line elements, containing global and local components were used. The global pattern structure produced interference effects on the visual-search task. All groups performed with the same speed and accuracy on the task involving the no-interference pattern, a finding attributed to reduced task difficulty. McConkie and Zola's model of visual attention was used to explain these results.