Unraveling the functional attributes of the language connectome: crucial subnetworks, flexibility and variability.

Language processing is a highly integrative function, intertwining linguistic operations (processing the language code intentionally used for communication) and extra-linguistic processes (e.g., attention monitoring, predictive inference, long-term memory). This synergetic cognitive architecture requires a distributed and specialized neural substrate. Brain systems have mainly been examined at rest. However, task-related functional connectivity provides additional and valuable information about how information is processed when various cognitive states are involved. We gathered thirteen language fMRI tasks in a unique database of one hundred and fifty neurotypical adults (InLang [Interactive networks of Language] database), providing the opportunity to assess language features across a wide range of linguistic processes. Using this database, we applied network theory as a computational tool to model the task-related functional connectome of language (LANG atlas). The organization of this data-driven neurocognitive atlas of language was examined at multiple levels, uncovering its major components (or crucial subnetworks), and its anatomical and functional correlates. In addition, we estimated its reconfiguration as a function of linguistic demand (flexibility) or several factors such as age or gender (variability). We observed that several discrete networks could be specifically shaped to promote key functional features of language: coding-decoding (Net1), control-executive (Net2), abstract-knowledge (Net3), and sensorimotor (Net4) functions. The architecture of these systems and the functional connectivity of the pivotal brain regions varied according to the nature of the linguistic process, gender, or age. By accounting for the multifaceted nature of language and modulating factors, this study can contribute to enriching and refining existing neurocognitive models of language. The LANG atlas can also be considered a reference for comparative or clinical studies involving various patients and conditions.

Perspectives from Young South African and Zimbabwean Women on Attributes of Four (Placebo) Vaginal Microbicide Delivery Forms.

INTRODUCTION: Incorporating end-user input into the design of new vaginal microbicides for women is key to optimizing their uptake, consistent use, and, ultimately, success in combatting the heterosexual HIV epidemic. METHODS: The Quatro Study assessed four placebo forms of vaginally inserted HIV-microbicides among young microbicide-naïve African women: on-demand film, insert and gel, and monthly ring. Participants randomly used each product for 1 month and provided product satisfaction ratings (1-5 scale), and opinions on product attributes and potential alternative designs. Qualitative data were collected through focus group discussions at study exit. Multivariable associations between attribute opinions and overall product rating were examined using Poisson regression models with robust standard errors to assess the attributes most influential to satisfaction. RESULTS: Overall opinions of products and their individual attributes were generally positive; all products were rated either 4 or a 5 by ≥ 50% of participants. Attributes related to ease of use and interference with normal activities were the most salient predictors of satisfaction. Preferences for duration of use tended toward relatively shorter use periods for the ring (i.e., 1-3 months vs. 12 months) and for coitally independent dosing for the on-demand products. CONCLUSIONS: How well a product fit in with participants' lifestyles was important to their overall satisfaction. For on-demand products, greater flexibility around timing of use was desired, to avoid coital dependency of the dosing.

Effect of oral administration of a continuous 18 day regimen of meloxicam on ovulation: experience of a randomized controlled trial.

BACKGROUND: Cyclooxygenase-2 (COX-2) is expressed in all female reproductive organs. Therefore, inhibitors of COX-2 may affect reproductive function. We evaluated the effect of extended administration of meloxicam on ovulation and the menstrual cycle. Our hypothesis was that meloxicam administered from menstrual cycle day 5- 22 could interfere with follicular rupture, without disrupting the menstrual cycle, and could be a potential non-hormonal contraceptive method. METHODS: The study was conducted in 56 healthy sterilized women. Before the onset of treatment and after the end of treatment, participants were observed during a control cycle to ensure that they had progesterone (P4) serum levels (>12 nmol/l) consistent with ovulation. Participants were treated for 18 days, during three consecutive cycles. They were randomized to 15 or 30 mg/day. The menstrual cycle was monitored with serial ultrasound and hormone assays in blood. RESULTS: Fifty-six volunteers completed the study. In 55% of cycles treated with 15 mg/day and in 78% of cycles treated with 30 mg/day (p<0.001) we observed dysfunctional ovulation defined as follicular rupture not preceded 24-48 h earlier by an LH peak or preceded by a blunted LH peak (<21 IU/l) or not followed by an elevated serum P4 level >12 nmol/l. Ovulation was observed in 44.6% and in 21.7% of women in the lower dose group and the higher dose group, respectively. There were no differences between the two doses in other parameters measured. There were no serious adverse events and adverse events were not different between doses or between control and treated cycles. CONCLUSIONS: Although administration of meloxicam on menstrual cycle days 5- 22 resulted in a dose-dependent inhibition of ovulation, more than 20% of subjects had normal ovulation with the highest dose. IMPLICATIONS: Previous studies have shown that oral meloxicam can delay follicle rupture. This study investigated daily oral meloxicam as a non-hormonal contraceptive. Since ovulation occurs in over 20% of cycles even with a high dose of 30 mg daily, it is not likely that the approach would be a highly effective contraceptive strategy.

The Role of Interferon Regulatory Factor-1 (IRF1) in Overcoming Antiestrogen Resistance in the Treatment of Breast Cancer.

Resistance to endocrine therapy is common among breast cancer patients with estrogen receptor alpha-positive (ER+) tumors and limits the success of this therapeutic strategy. While the mechanisms that regulate endocrine responsiveness and cell fate are not fully understood, interferon regulatory factor-1 (IRF1) is strongly implicated as a key regulatory node in the underlying signaling network. IRF1 is a tumor suppressor that mediates cell fate by facilitating apoptosis and can do so with or without functional p53. Expression of IRF1 is downregulated in endocrine-resistant breast cancer cells, protecting these cells from IRF1-induced inhibition of proliferation and/or induction of cell death. Nonetheless, when IRF1 expression is induced following IFNγ treatment, antiestrogen sensitivity is restored by a process that includes the inhibition of prosurvival BCL2 family members and caspase activation. These data suggest that a combination of endocrine therapy and compounds that effectively induce IRF1 expression may be useful for the treatment of many ER+ breast cancers. By understanding IRF1 signaling in the context of endocrine responsiveness, we may be able to develop novel therapeutic strategies and better predict how patients will respond to endocrine therapy.

Safety evaluation of 1% tenofovir gel in healthy men.

This study was conducted to determine the safety of tenofovir (TFV) gel, a potential microbicide, following seven consecutive daily penile applications. Eighteen circumcised and 18 uncircumcised healthy men were randomly assigned to TFV gel versus K-Y Jelly in a 2:1 ratio within circumcision group. TFV gel or K-Y Jelly was applied onto the penis at bedtime and washed off 6-10 hours later. Safety was assessed by reported symptoms, findings and laboratory tests. Three of 24 (13%) men in the TFV group reported mild genital symptoms compared with two of 11 (18%) men in the K-Y group. Few mild genital findings were observed and no significant systemic toxicities were reported or observed. TFV gel applied to the penis for seven days was well tolerated locally and systemically and it is unlikely that male partners exposed to small amounts of TFV gel will experience significant genital or systemic toxicity.

Lessons from the failure of human papillomavirus vaccine state requirements.

The licensure in 2006 of a vaccine against the subtypes of human papillomavirus (HPV) responsible for the majority of cervical cancers and genital warts was heralded as a watershed moment for vaccination, cancer prevention, and global health. A safe and effective vaccine against HPV has long been viewed as an enormous asset to cervical cancer prevention efforts worldwide. This is particularly true for places lacking robust Pap screening programs where cervical cancer has the greatest prevalence and mortality. Well before its licensure, however, some observers noted significant obstacles that would need to be addressed in order for an HPV vaccination program to succeed. These included the vaccine's relatively high cost, availability, and opposition from socially conservative groups. Such concerns associated with the implementation of HPV vaccination were soon overwhelmed by the furor that followed the unexpectedly early efforts by the US state governments to require the vaccine as a condition of attendance in public schools, proposals imprecisely referred to as "mandates." In this study, we review the controversy surrounding this debate and its effects on important ethical and public health issues that still need to be addressed.

Environmental Mutagen Society symposium on 'Risks of low dose, low dose rate exposures of ionizing radiation to humans'.

The Symposium, held in Vancouver, Canada, on 17 - 21 September 2006, was organized by the Environmental Mutagen Society, and it was their 37th Annual Meeting. Sessions were chaired by Drs W. F. Morgan and J. L. Schwartz, and papers were presented by Drs R.C. von Borstel, D. J. Brenner, J. L. Redpath, B. E. Erickson and A.L. Brooks.

Differential effects of ionic strength, divalent cations and pH on the pore-forming activity of Bacillus thuringiensis insecticidal toxins.

The combined effects of ionic strength, divalent cations, pH and toxin concentration on the pore-forming activity of Cry1Ac and Cry1Ca were studied using membrane potential measurements in isolated midguts of Manduca sexta and a brush border membrane vesicle osmotic swelling assay. The effects of ionic strength and divalent cations were more pronounced at pH 10.5 than at pH 7.5. At the higher pH, lowering ionic strength in isolated midguts enhanced Cry1Ac activity but decreased considerably that of Cry1Ca. In vesicles, Cry1Ac had a stronger pore-forming ability than Cry1Ca at a relatively low ionic strength. Increasing ionic strength, however, decreased the rate of pore formation of Cry1Ac relative to that of Cry1Ca. The activity of Cry1Ca, which was small at the higher pH, was greatly increased by adding calcium or by increasing ionic strength. EDTA inhibited Cry1Ac activity at pH 10.5, but not at pH 7.5, indicating that trace amounts of divalent cations are necessary for Cry1Ac activity at the higher pH. These results, which clearly demonstrate a strong effect of ionic strength, divalent cations and pH on the pore-forming activity of Cry1Ac and Cry1Ca, stress the importance of electrostatic interactions in the mechanism of pore formation by B. thuringiensis toxins.

Analysis of the properties of Bacillus thuringiensis insecticidal toxins using a potential-sensitive fluorescent probe.

A potential-sensitive fluorescent probe, 3,3'-dipropylthiadicarbocyanine iodide, was used to analyze, at pH 7.5 and 10.5, the effects of Bacillus thuringiensis toxins on the membrane potential generated by the efflux of K(+) ions from brush border membrane vesicles purified from the midgut of the tobacco hornworm, Manduca sexta. Fluorescence levels were strongly influenced by the pH and ionic strength of the media. Therefore, characterization of the effects of the toxins was conducted at constant pH and ionic strength. Under these conditions, the toxins had little effect on the fluorescence levels measured in the presence or absence of ionic gradients, indicating that the ionic selectivity of their pores is similar to that of the intact membrane. Valinomycin greatly increased the potential generated by the diffusion of K(+) ions although membrane permeability to the other ions used to maintain the ionic strength constant also influenced fluorescence levels. In the presence of valinomycin, active toxins (Cry1Aa, Cry1Ab, Cry1Ac, Cry1C and Cry1E) efficiently depolarized the membrane at pH 7.5 and 10.5.

Mifepristone followed on the same day by vaginal misoprostol for early abortion.

We performed a pilot study to examine the clinical efficacy of mifepristone 200 mg followed on the same day by misoprostol 800 microg vaginally in women with pregnancies up to 49 days gestation. Forty women received mifepristone 200 mg after which they self-inserted misoprostol intravaginally 6 to 8 h later at home. Participants returned for an evaluation, including transvaginal ultrasonography, 24 +/- 1 h after using the misoprostol. Participants who had not aborted received a second dose of misoprostol to administer 48 h after the mifepristone. All participants returned approximately 2 weeks after receiving mifepristone. At 24 h after receiving misoprostol, 37/40 (92%, 95% CI 81-98%) had ultrasonographic evidence of complete abortion. By follow-up 2 weeks after the mifepristone, 40/40 (100%, 95% CI 92-100%) women were felt to have complete abortions. One subject subsequently had a suction aspiration for an incomplete abortion on study Day 44. Nausea, vomiting, diarrhea, and warmth/chills occurred in 38%, 13%, 13%, and 60%, respectively. This pilot study suggests that mifepristone 200 mg, followed on the same day by misoprostol 800 microg vaginally, effects abortion at rates comparable to regimens using the standard time interval of 48 h between medications.

Ion channels induced in planar lipid bilayers by the Bacillus thuringiensis toxin Cry1Aa in the presence of gypsy moth (Lymantria dispar) brush border membrane.

The apical brush border membrane, the main target site of Bacillus thuringiensis toxins, was isolated from gypsy moth (Lymantria dispar) larval midguts and fused to artificial planar lipid bilayer membranes. Under asymmetrical N-methyl-d-glucamine-HCl conditions (450 mm cis/150 mm trans, pH 9.0), which significantly reduce endogenous channel activity, trypsin-activated Cry1Aa, a B. thuringiensis insecticidal protein active against the gypsy moth in vivo, induced a large increase in bilayer membrane conductance at much lower concentrations (1.1-2.15 nm) than in receptor-free bilayer membranes. At least 5 main single-channel transitions with conductances ranging from 85 to 420 pS were resolved. These Cry1Aa channels share similar ionic selectivity with P(Cl)/P(NMDG) permeability ratios ranging from 4 to 8. They show no evidence of current rectification. Analysis of the macroscopic current flowing through the composite bilayer suggested voltage-dependence of several channels. In comparison, the conductance of the pores formed by 100-500 nm Cry1Aa in receptor-free bilayer membranes was significantly smaller (about 8-fold) and their P(Cl)/P(NMDG) permeability ratios were also reduced (2- to 4-fold). This study provides a detailed demonstration that the target insect midgut brush border membrane material promotes considerably pore formation by a B. thuringiensis Cry toxin and that this interaction results in altered channel properties.

Unfolding affects insect cell permeabilization by Bacillus thuringiensis Cry1C toxin.

Bacillus thuringiensis Cry toxins are efficient, environment-friendly biological insecticides. Their molecular mode of action on target insect cells remains largely unknown. The aim of this study was to investigate the relation between the conformational state of the Cry1C toxin and its ionophoric activity on live Sf9 cells of Spodoptera frugiperda, a target insect for this protein. Potassium ion movement induced by Cry1C across the cell membrane was measured with a fluorescent assay developed previously and the conformation of the toxin was studied using tryptophan spectroscopy. Following treatment with 4 M guanidinium hydrochloride, which resulted in the unfolding of its N-terminal half, the toxin retained its full capacity to permeabilize the cells while the fully unfolded toxin did not induce potassium leakage. Therefore, permeabilization of Sf9 cells by Cry1C requires the integrity of the C-terminal half of the toxin and may depend on an initial unfolding step provided by the acidic environment of the cells.

Permeabilization of model lipid membranes by Bacillus sphaericus mosquitocidal binary toxin and its individual components.

The high larvicidal effect of Bacillus sphaericus (Bs), a mosquito control agent, originates from the presence of a binary toxin (Bs Bin) composed of two proteins (BinA and BinB) that work together to lyse gut cells of susceptible larvae. We demonstrate for the first time that the binary toxin and its individual components permeabilize receptor-free large unilamellar phospholipid vesicles (LUVs) and planar lipid bilayers (PLBs) by a mechanism of pore formation. Calcein-release experiments showed that LUV permeabilization was optimally achieved at alkaline pH and in the presence of acidic lipids. BinA was more efficient than BinB, BinB facilitated the BinA effect, and their stoichiometric mixture was more effective than the full Bin toxin. In PLBs, BinA formed voltage-dependent channels of approximately 100-200 pS with long open times and a high open probability. Larger channels (> or =400 pS) were also observed. BinB, which inserted less easily, formed smaller channels (< or =100 pS) with shorter mean open times. Channels observed after sequential addition of the two components, or formed by their 1:1 mixture (w/w), displayed BinA-like activity. Bs Bin toxin was less efficient at forming channels than the BinA/BinB mixture, with channels displaying the BinA channel behavior. Our data support the concept of BinA being principally responsible for pore formation in lipid membranes with BinB, the binding component of the toxin, playing a role in promoting channel activity.

Differential effects of pH on the pore-forming properties of Bacillus thuringiensis insecticidal crystal toxins.

The effect of pH on the pore-forming ability of two Bacillus thuringiensis toxins, Cry1Ac and Cry1C, was examined with midgut brush border membrane vesicles isolated from the tobacco hornworm, Manduca sexta, and a light-scattering assay. In the presence of Cry1Ac, membrane permeability remained high over the entire pH range tested (6.5 to 10.5) for KCl and tetramethylammonium chloride, but was much lower at pH 6.5 than at higher pHs for potassium gluconate, sucrose, and raffinose. On the other hand, the Cry1C-induced permeability to all substrates tested was much higher at pH 6.5, 7.5, and 8.5 than at pH 9.5 and 10.5. These results indicate that the pores formed by Cry1Ac are significantly smaller at pH 6.5 than under alkaline conditions, whereas the pore-forming ability of Cry1C decreases sharply above pH 8.5. The reduced activity of Cry1C at high pH correlates well with the fact that its toxicity for M. sexta is considerably weaker than that of Cry1Aa, Cry1Ab, and Cry1Ac. However, Cry1E, despite having a toxicity comparable to that of Cry1C, formed channels as efficiently as the Cry1A toxins at pH 10.5. These results strongly suggest that although pH can influence toxin activity, additional factors also modulate toxin potency in the insect midgut.

Mifepristone 100 mg in abortion regimens.

OBJECTIVE: To examine the clinical efficacy of mifepristone 100 mg followed 2 days later by misoprostol 400 microg orally or 800 microg vaginally in women at up to 49 days' gestation. METHODS: Eighty participants received mifepristone 100 mg and then were randomized to misoprostol, administered 48 hours later, at a dose of 400 microg orally (group 1) or 800 microg vaginally (group 2). Women returned for follow-up evaluations 24 +/- 1 hour after using the misoprostol and then 2-3 weeks later. If abortion still had not occurred and the pregnancy was nonviable, the subject returned again after an additional 3 weeks. RESULTS: Twenty-four hours after receiving misoprostol, 34 (85%; 95% confidence interval [CI] 71%, 94%) of the 40 women in group 1 and 38 (95%; 95% CI 85%, 99%) of the 40 women in group 2 had complete abortions. Overall, complete abortion without surgical intervention occurred in 34 women in group 1 (85%; 95% CI 71%, 94%) and 40 women in group 2 (100%; 95% CI 91%, 100%; P =.03). Four women in group 1 required suction aspiration for continuing pregnancy at the second follow-up, compared with none in group 2 (P =.12). Side effects occurred with similar frequency in both treatment groups. CONCLUSION: Low-dose mifepristone (100 mg) combined with vaginal misoprostol 800 microg may be an effective alternative to regimens using 200 or 600 mg of mifepristone with misoprostol.

Characteristics of chromosome instability in the human lymphoblast cell line WTK1.

The characteristics of spontaneous and radiation-induced chromosome instability were determined in each of 50 individual clones isolated from control populations of human lymphoblasts (WTK1), as well as from populations of these cells previously exposed to two different types of ionizing radiation, Fe-56 and Cs-137. The types of chromosome instability did not appear to change in clones surviving radiation exposure. Aneuploidy, polyploidy, chromosome dicentrics and translocations, and chromatid breaks and gaps were found in both control and irradiated clones. The primary effect of radiation exposure was to increase the number of cells within any one clone that had chromosome alterations. Chromosome instability was associated with telomere shortening and elevated levels of apoptosis. The results suggest that the proximal cause of chromosome instability is telomere shortening.

Effect of Bacillus thuringiensis Cry1 toxins in insect hemolymph and their neurotoxicity in brain cells of Lymantria dispar.

Little information is available on the systemic effects of Bacillus thuringiensis toxins in the hemocoel of insects. In order to test whether B. thuringiensis-activated toxins elicit a toxic response in the hemocoel, we measured the effect of intrahemocoelic injections of several Cry1 toxins on the food intake, growth, and survival of Lymantria dispar (Lepidoptera) and Neobellieria bullata (Diptera) larvae. Injection of Cry1C was highly toxic to the Lymantria larvae and resulted in the complete inhibition of food intake, growth arrest, and death in a dose-dependent manner. Cry1Aa and Cry1Ab (5 microg/0.2 g [fresh weight] [g fresh wt]) also affected growth and food intake but were less toxic than Cry1C (0.5 microg/0.2 g fresh wt). Cry1E and Cry1Ac (5 microg/0.2 g fresh wt) had no toxic effect upon injection. Cry1C was also highly toxic to N. bullata larvae upon injection. Injection of 5 microg/0.2 g fresh wt resulted in rapid paralysis, followed by hemocytic melanization and death. Lower concentrations delayed pupariation or gave rise to malformation of the puparium. Finally, Cry1C was toxic to brain cells of Lymantria in vitro. The addition of Cry1C (20 microg/ml) to primary cultures of Lymantria brain cells resulted in rapid lysis of the cultured neurons.

Diverse delayed effects in human lymphoblastoid cells surviving exposure to high-LET (56)Fe particles or low-LET (137)Cs gamma radiation.

To obtain information on the origin of radiation-induced genomic instability, we characterized a total of 166 clones that survived exposure to (56)Fe particles or (137)Cs gamma radiation, isolated approximately 36 generations after exposure, along with their respective control clones. Cytogenetic aberrations, growth alterations, responses to a second irradiation, and mutant frequencies at the Na(+)/K(+) ATPase and thymidine kinase loci were determined. A greater percentage of clones that survived exposure to (56)Fe particles exhibited instability (defined as clones showing one or more outlying characteristics) than in the case of those that survived gamma irradiation. The phenotypes of the unstable clones that survived exposure to (56)Fe particles were also qualitatively different from those of the clones that survived gamma irradiation. A greater percentage (20%) of the unstable clones that survived gamma irradiation than those that survived exposure to (56)Fe particles (4%) showed an altered response to the second irradiation, while an increase in the percentage of clones that had an outlying frequency of ouabain-resistant and thymidine kinase mutants was more evident in the clones exposed to (56)Fe particles than in those exposed to gamma rays. Growth alterations and increases in dicentric chromosomes were found only in clones with more than one alteration. These results underscore the complex nature of genomic instability and the likelihood that radiation-induced genomic instability arises from different original events.

Role of interdomain salt bridges in the pore-forming ability of the Bacillus thuringiensis toxins Cry1Aa and Cry1Ac.

The four salt bridges (Asp(222)-Arg(281), Arg(233)-Glu(288), Arg(234)-Glu(274), and Asp(242)-Arg(265)) linking domains I and II in Cry1Aa were abolished individually in alpha-helix 7 mutants D222A, R233A, R234A, and D242A. Two additional mutants targeting the fourth salt bridge (R265A) and the double mutant (D242A/R265A) were rapidly degraded during trypsin activation. Mutations were also introduced in the corresponding Cry1Ac salt bridge (D242E, D242K, D242N, and D242P), but only D242N and D242P could be produced. All toxins tested, except D242A, were shown by light-scattering experiments to permeabilize Manduca sexta larval midgut brush border membrane vesicles. The three active Cry1Aa mutants at pH 10.5, as well as D222A at pH 7.5, demonstrated a faster rate of pore formation than Cry1Aa, suggesting that increases in molecular flexibility due to the removal of a salt bridge facilitated toxin insertion into the membrane. However, all mutants were considerably less toxic to M. sexta larvae than to the respective parental toxins, suggesting that increased flexibility made the toxins more susceptible to proteolysis in the insect midgut. Interdomain salt bridges, especially the Asp(242)-Arg(265) bridge, therefore contribute greatly to the stability of the protein in the larval midgut, whereas their role in intrinsic pore-forming ability is relatively less important.

Genotoxic effects of high-energy iron particles in human lymphoblasts differing in radiation sensitivity.

The effects of (56)Fe particles and (137)Cs gamma radiation were compared in TK6 and WTK1 human lymphoblasts, two related cell lines which differ in TP53 status and in the ability to rejoin DNA double-strand breaks. Both cell lines were more sensitive to the cytotoxic and clastogenic effects of (56)Fe particles than to those of gamma rays. However, the mutagenicity of (56)Fe particles and gamma rays at the TK locus was the same per unit dose and was higher for gamma rays than for (56)Fe particles at isotoxic doses. The respective RBEs for TK6 and WTK1 cells were 1.5 and 1.9 for cytotoxicity and 2.5 and 1.9 for clastogenicity, but only 1 for mutagenicity. The results indicate that complex lesions induced by (56)Fe particles are repaired less efficiently than gamma-ray-induced lesions, leading to fewer colony-forming cells, a slightly higher proportion of aberrant cells at the first division, and a lower frequency of viable mutants at isotoxic doses. WTK1 cells (mutant TP53) were more resistant to the cytotoxic effects of both gamma rays and (56)Fe particles, but showed greater cytogenetic and mutagenic damage than TK6 cells (TP53(+)). A deficiency in the number of damaged TK6 cells (a) reaching the first mitosis after exposure and (b) forming viable mutants can explain these results.