Previously, our group demonstrated that tat depresses expression

Previously, our group demonstrated that tat depresses expression of DNA-PKcs, a critical component Autophagy Compound Library of the non-homologous end joining pathway (NHEJ) of DNA double-strand breaks repair, immunoglobulin class switch recombination (CSR) and V(D)J recombination, and sensitizes cells to ionizing radiation. In this study, we demonstrated that HIV-I Tat down-regulates DNA-PKcs expression by directly binding

to the core promoter sequence. In addition, Tat interacts with and activates the kinase activity of DNA-PKcs in a dose-dependent and DNA independent manner. Furthermore, Tat inhibits class switch recombination (CSR) at low concentrations ( smaller than = 4 mu g/ml) and stimulates CSR at high concentrations ( smaller than = 8 mu g/ml). On the other hand, low protein level and high kinase activity of DNA-PKcs promotes HIV-I transcription, while high protein level and low kinase activity inhibit HIV-I transcription. Co-immunoprecipitation results revealed that DNA-PKcs forms a large complex comprised of Cyclin TI, CDK9 and Tat via direct interacting with CDK9 and Tat but not Cyclin TI. Taken

together, our results provide new clues that Tat regulates host humoral immunity via both transcriptional depression and kinase activation of DNA-PKcs. We also raise the possibility that inhibitors and interventions directed towards DNA-PKcs may inhibit HIV-I transcription Ganetespib supplier in AIDS patients.”
“Van der Waals bound heterostructures constructed with two-dimensional MG0103 materials, such as graphene, boron nitride and transition metal dichalcogenides, have sparked wide interest in device physics and technologies at the two-dimensional limit. One highly coveted heterostructure is that of differing monolayer transition metal dichalcogenides with type-II band alignment, with bound electrons and holes localized in individual monolayers, that is, interlayer excitons. Here, we report the observation of interlayer excitons in monolayer MoSe2-WSe2 heterostructures by photoluminescence and photoluminescence

excitation spectroscopy. We find that their energy and luminescence intensity are highly tunable by an applied vertical gate voltage. Moreover, we measure an interlayer exciton lifetime of similar to 1.8 ns, an order of magnitude longer than intralayer excitons in monolayers. Our work demonstrates optical pumping of interlayer electric polarization, which may provoke further exploration of interlayer exciton condensation, as well as new applications in two-dimensional lasers, light-emitting diodes and photovoltaic devices.”
“The tight junctions (TJs) of epithelia are responsible for regulating the “fence and gate” function of polarized epithelial cells. It is now well-established that dysregulation of these functions contributes to initiation and progression of cancer.

(C) 2013 International Federation of Gynecology and Obstetrics P

(C) 2013 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.”
“. Women with factor X deficiency (FXD) who want to become pregnant face uncertain risks to themselves and to an unborn infant from haemorrhagic complications during pregnancy and AC220 research buy at parturition. Women with FXD may also experience difficulty achieving pregnancy secondary to haemorrhagic symptoms of the reproductive organs. Case reports describe differences in bleeding phenotypes and pregnancy outcomes that are not easily correlated with

prepregnancy bleeding symptoms or factor X levels. The aim of this article is to identify factors for consideration and information to assist the physician in counselling women with FXD who 4SC-202 in vitro want to become pregnant, and to offer guidelines for management where appropriate. We identified cases of pregnancy among women with FXD and their outcomes from the literature; 15 women with 24 pregnancies were identified and 18 were successful. The women in this small cohort did not have an increased rate of spontaneous abortion, (8.3% vs. 13.5% in the general US population) but did have a 2.5-fold increased risk of preterm labour (37.5% vs. 12.2% in the general US population). The role of prophylaxis to control reproductive haemorrhagic symptoms, including haemorrhagic complications of pregnancy

has not yet been defined, but use of prophylaxis may allow more women to be able to attempt selleck compound pregnancy. Women who had access to a tertiary care centre with a multidisciplinary team including an obstetrician with high-risk obstetric training, a haematologist, a perinatologist, and access to a reference laboratory and blood bank were able in most cases to successfully deliver healthy, term infants.”
“Objective\n\nA significant percentage of colonoscopies remain incomplete because of a failure to intubate the caecum. By double-balloon endoscopy (DBE), originally developed for deep enteroscopy, an otherwise incomplete examination

of the colon might be completed. We evaluated the success rate of caecal intubation, the reasons for its failure and the therapeutic consequences of using DBE after incomplete conventional colonoscopy.\n\nMethods\n\nWe report our single-centre experience of using DBE to complete an otherwise incomplete colonoscopy. A total of 114 consecutive patients, 45 male and 69 female, with a mean age of 64.8 years, who had undergone 116 procedures, were evaluated retrospectively by a review of their medical records.\n\nResults\n\nThe main causes for failed caecal intubation using a conventional colonoscope were loop formation in 70 patients (61.4%) and an adhesive angulated sigmoid in 33 (28.9%). Caecal intubation by DBE was successful in 101 patients (88.6%). The rate of failure was not associated with the cause of failure of the previous colonoscopy.

Conclusion: The DUOX-TPO association at the plasma membrane i

\n\nConclusion: The DUOX-TPO association at the plasma membrane is relevant for normal enzyme properties. Normally, TPO consumes H2O2 produced by DUOX, decreasing the availability of this substance at the apical membrane of thyrocytes and, in turn, probably decreasing the oxidative damage of macromolecules. (J Clin Endocrinol Metab 95: 5403-5411, 2010)”
“Wilms’ tumour (WT) is a pediatric tumor of the kidney that arises via failure of the fetal developmental program. The absence of identifiable mutations in the majority of WTs suggests the frequent involvement

of epigenetic aberrations in WT. We therefore conducted a genome-wide analysis of promoter hypermethylation in WTs and identified hypermethylation at chromosome 5q31 spanning 800 kilobases (kb) and more than 50 genes. The methylated genes all belong to alpha-, beta-, PD-1/PD-L1 inhibitor drugs and gamma-protocadherin (PCDH) gene clusters (Human Genome Organization nomenclature PCDHA@, PCDHB@, and PCDHG@, respectively). This demonstrates that long-range epigenetic silencing (LRES) occurs in developmental tumors as well as in adult tumors. Bisulfite polymerase chain reaction analysis showed that PCDH hypermethylation is a frequent event found in all Wilms’ tumor

subtypes. Hypermethylation is concordant with reduced PCDH expression in tumors. WT precursor lesions showed no PCDH hypermethylation, suggesting that de novo PCDH hypermethylation occurs during malignant progression. Discrete boundaries AZD6244 of the PCDH domain are delimited by abrupt changes in histone Selleckchem HM781-36B modifications; unmethylated genes flanking the LRES are associated with permissive marks which are absent from methylated genes within the domain. Silenced genes are marked with non-permissive histone 3 lysine 9 dimethylation. Expression analysis of embryonic murine kidney and differentiating rat metanephric mesenchymal

cells demonstrates that Pcdh expression is developmentally regulated and that Pcdhg@ genes are expressed in blastemal cells. Importantly, we show that PCDHs negatively regulate canonical Wnt signalling, as short-interfering RNA-induced reduction of PCDHG@ encoded proteins leads to elevated beta-catenin protein, increased beta-catenin/T-cell factor (TCF) reporter activity, and induction of Wnt target genes. Conversely, over-expression of PCDHs suppresses beta-catenin/TCF-reporter activity and also inhibits colony formation and growth of cancer cells in soft agar. Thus PCDHs are candidate tumor suppressors that modulate regulatory pathways critical in development and disease, such as canonical Wnt signaling.”
“Backgrounds and purpose: To determine the predictors for recurrence in patients receiving curative hepatectomy for hepatocellular carcinoma (HCC).

Additionally, the strongest OsDUR3-expression occurred in seedlin

Additionally, the strongest OsDUR3-expression occurred in seedlings on no-nitrogen or 1 mM urea.\n\nWe suggest that insufficient urea-absorption but not assimilation represents likely a factor contraining rice to use urea as sole nitrogen-source.”
“In the Colombian Caribbean Sea a shallow water commercial shrimp fishery has been developed, targeting mainly Farfantepenaeus notialis. Yet, similarly to so many fisheries around the world, the exploitation of this shrimp is not regulated, and a significant depletion has resulted. This study investigates

Tariquidar chemical structure new fishing areas, exploring the poorly understood deep-sea habitats in the Colombian Caribbean Sea, to determine the potential for a viable deep shrimp fishery, studying their abundance and spatial distribution. We found high abundances for giant red shrimp (Aristaeomorpha foliacea) and royal red shrimp (Pleoticus robustus), both important commercially. The higher biomass of these two deep-sea shrimp species were found mainly in the northern zone of the Colombian Caribbean Sea, where the local oceanography is modulated by the seasonal upwelling with high productivity. The size-structure following depth strata

VE-821 supplier showed that A. foliacea increase in size with the depth and the contrary for P. robustus. The majority of adult individuals in these two deep-sea shrimp species reflect the non-fished populations in the study area. However, more scientific assessment is necessary to determine life cycle population parameters of deep-sea shrimps and associated biodiversity before initiating a new commercial shrimp fishery.”
“This communication describes platelet indices including platelet count (PLT), mean platelet volume (MPV), plateletcrit (PCT) and platelet distribution width (PDW), along with parallel red blood cell parameters, in samples from 27 dromedary camels of both sexes. The overall mean values of the platelet parameters were: PLT 319.71 +/- 38.6 (x10(9)/L); MPV 5.51 +/- 0.08 fL; PCT 0.14 +/- 0.02% and PDW 19.50

+/- 0.62%. A highly significant click here correlation was found between PLT and PCT (P <= 0.001) in male, female and all camels and a significant correlation between MPV and PDW (P<0.05) in male and all camels. The correlation between platelet parameters and parallel red blood cell parameters, namely: hematocrit (HCT), mean corpuscular volume (MCV) and red cell distribution width (RDW), revealed no significant correlation between RBC and PLT, PCT and HCT or MPV and MCV. However, a highly significant correlation was found between PCT and RDW in all camels (P <= 0.005). This is the first report of MPV, PCT, PDW and RWD in dromedaries.”
“Treatment for prostate cancer (PCa) has evolved significantly over the last decade.

In contrast, Podxl(Delta EC) endothelial cells exhibit a severely

In contrast, Podxl(Delta EC) endothelial cells exhibit a severely impaired ability to spread on laminin and, to a lesser extent, collagen I coated transwells. The data suggest that, in endothelial cells, podocalyxin plays a previously unrecognized role in maintaining vascular integrity, likely through orchestrating interactions with extracellular matrix components and basement membranes, and that this influences downstream epithelial architecture.”
“Intracellular ATP, the energy source for many reactions, is crucial for the activity of plasma membrane pumps and, thus, for the maintenance

click here of transmembrane ion gradients. Nevertheless, ATP and other nucleotides/nucleosidesare also extracellular molecules that regulate diverse cellular functions, including ion transport. In this review, I will first introduce the main components of the extracellular ATP signalling, which have become known as the purinergic signalling system. With more than 50 components or find more processes, just at cell membranes, it ranks as one of the most versatile signalling systems. This multitude of system components may enable differentiated regulation of diverse epithelial functions. As epithelia probably face the widest variety of potential ATP-releasing stimuli, a special

attention will be given to stimuli and mechanisms of ATP release with a focus on exocytosis. Subsequently, I will consider membrane transport of major ions (Cl-, HCO3-, K+ and Na+) and integrate possible regulatory functions of P2Y2, P2Y4, P2Y6, P2Y11, P2X4, P2X7 and adenosine receptors in some selected epithelia at the cellular level. Some purinergic receptors Saracatinib have note-worthy roles. For example, many studies to date indicate that the P2Y2 receptor is one common denominator in regulating ion channels on both the luminal and basolateral membranes

of both secretory and absorptive epithelia. In exocrine glands though, P2X4 and P2X7 receptors act as cation channels and, possibly, as co-regulators of secretion. On an organ level, both receptor types can exert physiological functions and together with other partners in the purinergic signalling, integrated models for epithelial secretion and absorption are emerging.”
“Salt-inducible kinase (SIK), one of the AMP-activated kinase (AMPK)-related kinases, has been suggested to play important functions in glucose homeostasis by inhibiting the cAMP-response element-binding protein (CREB)-regulated transcription coactivator (CRTC). To examine the role of SIK in vivo, we generated Drosophila SIK mutant and found that the mutant flies have higher amounts of lipid and glycogen stores and are resistant to starvation.


“Vulcanization gives birth to the nonuniformity of rubber


“Vulcanization gives birth to the nonuniformity of rubber network, the identification of which selleck chemicals is the basis of improvement of performance of rubber products. We established a visco-hyperelastic

constitutive equation to reveal the quantitative distribution of the inhomogeneous network phases according to a three-phase model. The cross-linked network was assumed to be composed of the cross-linking cluster, the low network chain density domain and the fluid-like mass. The incorporation of clay with high specific surface area induced the effective uniformity of network structure by decreasing the content of the cross-linking cluster and increasing that of the low network chain density domain. These structural variations were responsible for excellent mechanical properties and strong strain-induced crystallization ability probed by the in situ synchrotron wide-angle X-ray diffraction. (c) 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40324.”
“Nitroepoxides are easily transformed into 1,4-diamino heterocycles such as quinoxalines and pyrazines by treatment

with 1,2-benzenediamines and ammonia, respectively. Additionally, related saturated heterocycles, such as piperazines and tetrahydroquinoxalines, can be accessed by treatment with 1,2-diamines and a reducing agent. These transformations are efficient, provide access privileged, bioactive structures, and produce minimal waste.”
“Background: EMR at the anorectal junction (ARJ) is technically challenging. Issues of safety and procedural efficacy dictate that surgery is still performed as the primary management for noninvasive lesions in most centers. Modifications see more to the standard EMR technique may help to address the unique features and achieve safe and curative resection of most

lesions. Objective: To describe an effective and safe, modified EMR technique to remove advanced mucosal neoplasia (AMN) of the ARJ. Design: Prospective, observational cohort study. Setting: Academic, tertiary care referral center. Patients: Patients undergoing EMR for AMN at the ARJ over 4.5 years, from June 2008 to December 2012. Interventions: Use of long-acting local anesthetic in the submucosal injectate, endoscopic resection over the dentate line and hemorrhoidal columns, prophylactic antibiotics for resection of lesions at high risk for bacteremia, and cap and gastroscope-assisted resection. https://www.selleckchem.com/products/ml323.html Main Outcome Measurements: Procedural success and safety. Results: Twenty-six patients with lesions involving the ARJ were referred for EMR (males 53.8%, median age 63, median lesion size 40 mm). Two patients went directly to surgery because of an endoscopic diagnosis of adenocarcinoma. EMR was performed in 24 lesions with complete adenoma clearance achieved in 100%. Four patients were admitted to the hospital. Focal adenoma recurrence was seen in 4 of 18 patients (22%) at first surveillance colonoscopy and was managed by snare diathermy resection.

Computational results show that instances involving up to 255 cus

Computational results show that instances involving up to 255 customers and 25 possible depots can be solved optimally using the proposed methodology.”
“Background: This study was designed to assess whether cardiovascular

magnetic resonance imaging (CMR) in Duchenne muscular dystrophy carriers (DMDc) may index any cell milieu elements buy DMXAA of LV dysfunction and whether this cardiac phenotype may be related to genotype. The null hypothesis was that myocardial fibrosis, assessed by late gadolinium enhancement (LGE), might be similarly accounted for in DMDc and gender and age-matched controls. Methods: Thirty DMDc patients had CMR and genotyping with 37 gender and age-matched controls. Systolic and diastolic LV function was assessed by 2D-echocardiography. Results: Absolute and percent LGE were higher in muscular symptomatic (sym) than asymptomatic (asy) DMDc (1.77 +/- 0.27 vs 0.76 +/- 0.17 ml; F = 19.6,

p smaller than 0.0001 and 1.86 +/- 0.26% vs 0.68 +/- 0.17%, F = 22.1, p smaller than 0.0001, respectively). There was no correlation between LGE and age. LGE was seen most frequently in segments 5 and 6; segment 5 was involved in all asy-DMDc. Subepicardial LGE predominated, compared to the mid-myocardial SNX-5422 one (11 out of 14 DMDc). LGE was absent in the subendocardium. No correlations were seen between genotyping (type of mutation, gene region and protein domain), confined to the exon’s study, and cardiac phenotype.

Conclusions: A typical myocardial LGE-pattern location (LV segments 5 and 6) was a common finding in DMDc. LGE was more frequently subepicardial MG-132 plus midmyocardial in sym-DMDc, with normal LV systolic and diastolic function. No genotype-phenothype correlation was found.”
“A new general model for describing intersecting multidimensional potential energy surfaces when motions of large amplitude are involved is presented. This model can be seen as an extension of the vibronic coupling models of Koppel et al. ["Multimode molecular dynamics beyond the Born-Oppenheimer approximation," Adv. Chem. Phys. 57, 59 (1984)]. In contrast to the original vibronic coupling models, here the number of diabatic states is larger than the number of adiabatic states and curvilinear coordinates are used in a systematic way. Following general considerations, the approach is applied to the fitting of the potential energy surfaces for the very complex nonadiabatic photodynamics of benzopyran. Preliminary results are presented at the complete active space self-consistent field level of theory and with up to 12 active degrees of freedom. Special emphasis is placed on the physical interpretation of the diabatic states and on the influence of the various degrees of freedom on the fit. (C) 2014 AIP Publishing LLC.

Results of Ilex cymosa species for adventitious root induction pe

Results of Ilex cymosa species for adventitious root induction per microcutting was markedly different from other https://www.selleckchem.com/products/sn-38.html species and it produced the highest number of adventitious roots (14.07 roots/microcutting). A. korthalsii generated the fewer, but the heaviest roots compared to I. cymosa. Rooting ability of microcuttings was highly correlated with its number of leaves produced during

rooting (r = 0.869-0.981) as well as, with regenerative shoot length of the mother plants (r = 0.690-0.954). Regenerative leaf growth of mother plants and the rooting of their microcuttings was species-specific suggesting that developing association between the two parameters is difficult.”
“Flexible polyurethane foam (FPF) is produced from the reaction of toluene diisocyanate (TDI) and polyols. Because of the potential for respiratory sensitization following exposure to TDI, concerns have been raised about potential consumer exposure to TDI from residual free TDI in FPF

products. Limited and conflicting results exist in the literature concerning the presence of unreacted TDI remaining in FPF as determined by various solvent extraction and analysis techniques. Because residual TDI results are most often intended for application in assessment of potential human exposure to TDI from FPF products, testing techniques that more accurately simulated human contact with foam were designed. To represent inhalation exposure

to TDI from polyurethane foam, a test that measured the emission Poziotinib concentration of TDI to air was conducted. For simulation of human dermal exposure to TDI from polyurethane foam, a migration test technique was designed. Emission of TDI to air was determined for a representative FPF using three different emission test cells. Two were commercially available cells that employ air flow over the surface of the foam [the Field and Laboratory Emission Cell (FLEC) and the Micro-Chamber/Thermal Extraction cell]. The third emission test cell was of a custom design and features air flow through the foam sample Z-IETD-FMK inhibitor rather than over the foam surface. Emitted TDI in the air of the test cells was trapped using glass fiber filters coated with 1-(2-methoxyphenyl)-piperazine (MP), a commonly used derivatizing agent for diisocyanates. The filters were subsequently desorbed and analyzed by liquid chromatography/mass spectrometry. Measurement of TDI migration from representative foam was accomplished by placing glass fiber filters coated with MP on the outer surfaces of a foam disk and then compressing the filters against the disk using a clamping apparatus for periods of 8 and 24 h. The sample filters were subsequently desorbed and analyzed in the same manner as for the emission tests.

Both cream formulations were assessed,

using Visioscan VC

Both cream formulations were assessed,

using Visioscan VC 98, for various parameters including texture parameters (energy, contrast and variance) as well as for skin roughness (Ser), skin scaliness (SEsc), skin smoothness (SEsm) and skin wrinkles (Sew).\n\nResults: Unlike the cream base, the extract cream exhibited steady, significant improvement in skin parameters over the 3-month period of application. Images showed visible improvement of the overall skin appearance and reduction of fine lines by the extract cream. Furthermore, learn more skin texture (variance and contrast) and SELS (SEr, SEsc, SEsm and SEw) parameters showed significant decline (p < 0.05) and the texture parameter of energy showed significant increase (p < 0.05).\n\nConclusion: Our findings indicate that the cream containing 3 % Acacia nilotica bark extract possesses anti-aging effect and improves skin surface

appearance..”
“An Hologic QDR4500A dual energy X-ray absorptiometer (DXA) was used to measure live body composition in 15 second-cross wether lambs ((Border Leicester x Merino) x Poll Dorset) aged 6-8 months (17-50 kg) and 13 mature ewes (composite terminal sire line based largely on Poll Dorset, White Suffolk and Texel breeds) (44-71 kg). After slaughter, DXA scans were also performed on the whole carcasses. Values determined by DXA including total tissue mass (TTM), Selisistat lean tissue mass (LTM), fat tissue mass (FTM) and bone mineral content (BMC) for the half carcass were evaluated by comparison with chemically determined composition. In the case of

BMC the relationship was with chemically determined check details ash content. Live weight and chemically determined lean, fat and ash were strongly related to DXA-derived values for whole body TTM, LTM, FTM and BMC, respectively (R(2) = 0.999, 0.988, 0.980 and 0.977, respectively). Carcass weight and chemically determined lean, fat and ash were strongly related to DXA-derived values for carcass TTM, LTM, FTM and BMC, respectively (R(2) = 0.998, 0.984, 0.986 and 0.906, respectively). However, because DXA estimates were different from chemically determined values in this sample of carcasses, they needed to be adjusted with the use of appropriate regression equations to correct the inbuilt algorithms used to predict human body composition. These data demonstrate the efficacy of DXA as a non-destructive method for determining the composition of the whole body and carcasses of sheep. (C) 2011 Elsevier B.V. All rights reserved.”
“Background: Data from a dietary-reporting validation study with fourth-grade children were analyzed to investigate a possible relationship of body mass index (BMI) with daily participation in school meals and observed energy intake at school meals, and whether the relationships differed by breakfast location (classroom; cafeteria).\n\nMethods: Data were collected in 17, 17, and 8 schools during three school years.

Despite maintained carcinogen exposure, tumors from smokers showe

Despite maintained carcinogen exposure, tumors from smokers showed a relative decrease in

smoking-related mutations over time, accompanied by an increase in APOBEC-associated mutations. In tumors from former smokers, Sapanisertib inhibitor genome-doubling occurred within a smoking-signature context before subclonal diversification, which suggested that a long period of tumor latency had preceded clinical detection. The regionally separated driver mutations, coupled with the relentless and heterogeneous nature of the genome instability processes, are likely to confound treatment success in NSCLC.”
“IMPORTANCE Most out-of-hospital cardiac arrests receiving emergency medical services in the United States are treated by ambulance service providers trained in advanced life support (ALS), but supporting evidence for the use of ALS over basic life support (BLS) is limited. OBJECTIVE To compare the effects of BLS and ALS on outcomes after out-of-hospital cardiac arrest. DESIGN, SETTING, AND PARTICIPANTS Observational cohort study of a nationally representative sample of traditional Medicare beneficiaries from nonrural counties who experienced out-of-hospital cardiac arrest between January 1, 2009, and October 2, 2011, and for whom ALS JNK screening or BLS ambulance services were billed to Medicare (31 292 ALS cases and 1643 BLS cases). Propensity score

methods were used to compare the effects of ALS and BLS on patient survival, neurological performance, and medical spending after cardiac arrest. MAIN OUTCOMES AND MEASURES Survival to hospital discharge, to 30 days, and to 90 days; neurological performance; and incremental medical spending per additional survivor to 1 year. RESULTS Survival to hospital discharge was greater among patients receiving BLS (13.1% vs 9.2% for ALS; 4.0 [95% CI, 2.3-5.7] percentage

point difference), as was survival to 90 days (8.0% vs 5.4% for ALS; 2.6 [95% CI, 1.2-4.0] percentage point difference). Basic life support was associated with better neurological functioning among hospitalized patients (21.8% vs 44.8% with poor neurological functioning for ALS; 23.0 [95% CI, 18.6-27.4] percentage point difference). Incremental medical spending per additional survivor to 1 year DMXAA cost for BLS relative to ALS was $ 154 333. CONCLUSIONS AND RELEVANCE Patients with out-of-hospital cardiac arrest who received BLS had higher survival at hospital discharge and at 90 days compared with those who received ALS and were less likely to experience poor neurological functioning.”
“It has long been speculated that cellular microdomains are important for many cellular processes, especially those involving Ca2+ signalling. Measurements of cytosolic Ca2+ report maximum concentrations of less than few micromolar, yet several cytosolic enzymes require concentrations of more than 20 mu M Ca2+ to be activated.