Rice husk-derived mesoporous biogenic silica nanoparticles for gravity chromatography.

Biogenic silica nanoparticle is a superb alternative to synthetic silica because of their highly active, polar, and porous nanostructure with a large interior area. Among the available agricultural bioresources, biogenic silica extracted from rice husks could be a simple, easily available, and cost-effective resource to use as the stationary phase for the column chromatographic technique. In the present study, highly pure amorphous biogenic silica nanoparticles (bSNPs) were synthesized using rice husk by a controlled combustion route followed by the sol-gel method. The bSNPs show better performance for the separation and isolation of ortho- and para-nitrophenol and nitroaniline. The outstanding performance of the as-synthesized bSNPs is attributed to the high surface area, high porosity, and presence of Si-OH polar bonds. These preliminary findings imply that rice husk, an agricultural waste, could be an alternative source of silica and applicable as a stationary phase in column chromatography.

Update of survival and cost of metastatic melanoma with new drugs: Estimations from the MelBase cohort.

PURPOSE: Since 2011, significant progress was observed in metastatic melanoma (MM), with the commercialisation of seven immunotherapies or targeted therapies, which showed significant improvement in survival. In France, in 2004, the cost of MM was estimated at €1634 per patient; this cost has not been re-estimated since. This study provided an update on survival and cost in real-life clinical practice. METHODS: Clinical and economic data (treatments, hospitalisations, radiotherapy sessions, visits, imaging and biological exams) were extracted from the prospective MelBase cohort, collecting individual data in 955 patients in 26 hospitals, from diagnosis of metastatic disease until death. Survival was estimated by the Kaplan-Meier method. Costs were calculated from the health insurance perspective using French tariffs. For live patients, survival and costs were extrapolated using a multistate model, describing the 5-year course of the disease according to patient prognostic factors and number of treatment lines. RESULTS: Since the availability of new drugs, the mean survival time of MM patients has increased to 23.6 months (95%confidence interval [CI] :21.2;26.6), with 58% of patients receiving a second line of treatment. Mean management costs increased to €269,682 (95%CI:244,196;304,916) per patient. Drugs accounted for 80% of the total cost. CONCLUSION: This study is the first that evaluated the impact of immunotherapies and targeted therapies both on survival and cost in real-life conditions. Alongside the introduction of breakthrough therapies in the first and subsequent lines, MM has been associated with a significant increase in survival but also in costs, raising the question of financial sustainability.

Effects of preference and sensory modality on behavioural reaction in patients with disorders of consciousness.

BACKGROUND: Reliable evaluation of patients with unresponsive wakefulness syndrome (UWS) or in a minimally conscious state (MCS) remains a major challenge. It has been suggested that the expression of residual cerebral function could be improved by allowing patients to listen to their favourite music. However, the potential effect of music on behavioural responsiveness, as well as the effect of preferred stimuli in other sensory modalities (e.g. olfaction), remain poorly understood. OBJECTIVE: The aim of our study was to investigate the effect of sensory modality (auditory versus olfactory) and preference (preferred versus neutral) of the test stimuli on patients' subsequent performance on the Coma Recovery Scale-Revised (CRS-R). RESEARCH DESIGN: Within-subject design because of inter-individual differences between patients. METHODS AND PROCEDURES: We studied four items from the CRS-R (visual pursuit using a mirror, auditory localization of the own name and two movements to command) in 13 patients (7 MCS; 6 UWS). MAIN OUTCOMES AND RESULTS: Auditory stimuli triggered higher responsiveness compared to olfactory stimuli, and preferred stimuli were followed by higher scores than did neutral stimuli. CONCLUSIONS: Findings suggest that preferred auditory stimuli at the bedside contribute to the expression of residual function and could improve the diagnostic assessment.

Non-invasive cerebral stimulation for the upper limb rehabilitation after stroke: a review.

Numerous studies have recently been published on improving upper-limb motor function after stroke. There has been a particular interest in brain stimulation techniques, which could promote brain plasticity. In this review, transcranial Direct Current Stimulation (tDCS) and repetitive Transcranial Magnetic Stimulation (rTMS) are presented as techniques that could be relevant in Physical Medicine and Rehabilitation (PM&R) centers in the future. We are presenting a comprehensive literature review on the studies using tDCS or rTMS for upper-limb rehabilitation after a stroke. Both techniques have shown their ability to modify cortical excitability and to transitorily improve upper-limb function after one single stimulation session. The first placebo-controlled, blinded therapeutic trials, which included repeated daily sessions, seem quite promising, and deserve to be validated by further trials.

[Reproducibility study of the "400 Points assessment", a measurement of the hand's functional ability]. / Étude de reproductibilité de la cotation du « Bilan 400 points ¼, une mesure de capacité fonctionnelle de la main.

OBJECTIVES: Evaluate the inter-rater and test-retest reproducibility of the "400 Points assessment", a measurement of the functional ability of the hand. The scale included four tests: function of the hand, prehension strengths, handling and displacement of things, and function with both hands. METHODS: Thirty patients with hand injuries were participated. The inter-rate agreements were examinated between three occupational therapists. The First rater was an experienced user of this instrument (observer 1), the second one was a novice user (observer 2), the last rater is a student who had never used it before (observer 3). Subjects were tested twice by the same raters independently, with 30 minutes intervals between tests. Statistical analysis was done by calculating average differences and intraclass correlation coefficient. RESULTS: (i) The difference between the three raters agreements was small for the two measurements, except for function with both hands in the second period. Every intraclass correlation coefficient was higher than 0.95. (ii) Difference between the two measurements was small for every observer. These differences are not significant except for function with both hands. Intraclass correlation coefficients are all higher than 0.82 even than 0.90 for the total score. The difference between the two periods for the overall test is small, from 5% to 10% for seven patients and from 10 to 15% for two patients. Differences at two times had the same agreement for the three observers. CONCLUSION: "400 Points assessment" is reproducible (inter-rater and test-retest reproductibility). The test "function with both hands" requires more experience of the assessment.

Germline E-cadherin mutations in familial lobular breast cancer.

BACKGROUND: The cell surface glycoprotein E-cadherin (CDH1) is a key regulator of adhesive properties in epithelial cells. Germline mutations in CDH1 are well established as the defects underlying hereditary diffuse gastric cancer (HDGC) syndrome, and an increased risk of lobular breast cancer (LBC) has been described in HDGC kindreds. However, germline CDH1 mutations have not been described in patients with LBC in non-HDGC families. This study aimed to investigate the frequency of germline CDH1 mutations in patients with LBC with early onset disease or family histories of breast cancer without DGC. METHODS: Germline DNA was analysed in 23 women with invasive lobular or mixed ductal and lobular breast cancers who had at least one close relative with breast cancer or had themselves been diagnosed before the age of 45 years, had tested negative for a germline BRCA1 or BRCA2 mutation, and reported no personal or family history of diffuse gastric cancer. The full coding sequence of CDH1 including splice junctions was amplified using PCR and screened for mutations using DHPLC and sequencing. RESULTS: A novel germline CDH1 truncating mutation in the extracellular portion of the protein (517insA) was identified in one woman who had LBC at the age of 42 years and a first degree relative with invasive LBC. CONCLUSIONS: Germline CDH1 mutations can be associated with invasive LBC in the absence of diffuse gastric cancer. The finding, if confirmed, may have implications for management of individuals at risk for this breast cancer subtype. Clarification of the cancer risks in the syndrome is essential.

Mortality from cardiovascular diseases in the German uranium miners cohort study, 1946-1998.

An increased risk of cardiovascular diseases after exposure to low doses of ionizing radiation has been suggested among the atomic bomb survivors. Few and inconclusive results on this issue are available from miner studies. A positive correlation between coronary heart disease mortality and radon exposure has been reported in the Newfoundland fluorspar miners study, yet low statistical power due to small sample size was of concern. To get further insight into this controversial issue, data from the German uranium miners cohort study were used, which is by far the largest miner study up to date. The cohort includes 59,001 male subjects who were employed for at least six months between 1946 and 1989 at the former Wismut uranium company in Eastern Germany. Exposure to radon, long-lived radionuclides and external gamma radiation was estimated by using a detailed job-exposure matrix. About 16,598 cohort members were deceased until 31 December 1998, including 5,417 deaths from cardiovascular diseases. Linear Poisson regression models were used to estimate the excess relative risk (ERR) per unit of cumulative radiation exposure after adjusting for attained age and calendar period. No trend in risk of circulatory diseases with increasing cumulative exposure to either radon [ERR per 100 working level month: 0.0006; 95% confidence limit (CI): -0.004 to 0.006], external gamma radiation (ERR per Sv: -0.26, 95% CI: -0.6 to 0.05) or long-lived radionuclides (ERR per 100 kBqh/m3: -0.2, 95% CI: -0.5 to 0.06), respectively, was observed. This was also true for the sub-group heart disease and stroke. Our findings do not support an association between cardiovascular disease mortality and exposure to radiation among miners, yet low doses and uncontrolled confounding hamper interpretation.

Cisplatinum rechallenge in relapsed ovarian cancer patients with platinum reinduction therapy and carboplatin hypersensitivity.

Hypersensitivity reactions have been reported as limiting side effect in patients re-exposed to carboplatin for relapsed gynecologic malignancy. This study analyzed the incidence, clinical features, management, and outcome of carboplatin-associated hypersensitivity reactions. We performed a retrospective study and analyzed medical records of all gynecological cancer patients treated with carboplatin in our institution from 2000 to 2003. No hypersensitivity reactions were observed in 171 patients during the first carboplatin-containing chemotherapy. All six carboplatin-associated hypersensitivity reactions occurred in 69 patients who were re-exposed to carboplatin (9%). The median number of carboplatin cycles prior to hypersensitivity reaction was nine (range, 8-13). Cisplatin rechallenge was performed in five patients, and no hypersensitivity occurred. An increase in neurotoxicity (National Cancer Institute Common Toxicity Criteria grade 2) was documented in two patients who had residual neurotoxicity grade 1 due to prior taxane treatment. Cisplatinum rechallenge is a feasible strategy to overcome carboplatin hypersensitivity. However, close monitoring of neurotoxicity is necessary, particularly in patients with residual neurotoxicity due to prior platinum- and taxane-containing chemotherapy.

G protein-linked receptors labeled by [3H]histamine in guinea pig cerebral cortex. I. Pharmacological characterization [corrected].

Binding of histamine to washed membranes from guinea pig cerebral cortex can be described empirically as two classes of distinct and independent sites (log IP1 = -8.45 +/- 0.02, R1;t = 98 +/- 6 pmol/g of protein; log KP2 = -6.34 +/- 0.22, R2.t = 990 +/- 60 pmol/g of protein). At 1.4 nm [3H]histamine, the kinetics of association and dissociation are biexponential. The values of k-Pj/k+Pj calculated for parallel one-step processes agree well with the corresponding values of KPj. Both k-p1 and k-P2 are increased by 0.1 mM guanylylimidodiphosphate; apparent capacity at equilibrium is reduced for both classes of sites, with little or no change in KP1 or KP2. Twenty-six H2 and H3 agonists and antagonists block access of [3H]histamine to the same sites, and the binding patterns reveal either one or two hyperbolic terms [i.e., sigma nj = 1 F' jKj/(Kj+[L])]. Two terms are required for six agonists and six antagonists, and F'2 varies widely from ligand to ligand. Also, the quantity log (K2/K1) is correlated with F'1 among agonists but with F'2 among antagonists (K1 < K2). The pharmacological selectivity is suggestive of both H2 and H3 receptors. An H2 specificity emerges from the appropriate values of Kj for 12 H2 agonists (i.e., K1 when n = 1 and K2 when n = 2; p = 0.00045), although a specificity distinct from that of H2 receptors is found with H2 antagonists. An H3 specificity emerges from the inhibitory potencies (IC50) of eight H3 agonists (p = 0.00025) and eight H3 antagonists (p = 0.0019); also, the sites labeled by [3H]histamine resemble H3 receptors reportedly labeled by N alpha-[3H]methylhistamine and (R)-alpha-[3H]methylhistamine. Ligand-dependent differences in F'2 are inconsistent with the notion of distinct and independent sites, and the tendency of antagonists to promote the sites of weaker affinity (F'2) argues against a ligand-regulated equilibrium between two states. The physical significance of the binding parameters is therefore unclear. The failure to identify an unambiguous pharmacological specificity may reflect the failure to assess binding in the correct mechanistic context.

H2 histaminic receptors in rat cerebral cortex. 2. Inhibition of [3H]histamine by H2 antagonists.

Sites labeled by [3H]histamine in homogenates of rat cerebral cortex reveal a pharmacological specificity typical of H2 receptors. Fourteen H2 antagonists inhibit the specific binding of the radioligand to the same level; Hill coefficients are near or equal to one for five compounds and markedly lower for nine. The binding patterns of individual antagonists (A) are well described by the empirical expression Y = F1K1/(K1 + [A]) + F2K2/(K2 + [A]), in which F1 and F2 sum to 1; F2 is 0 for those drugs that reveal a Hill coefficient of 1. Concentrations of A that reduce specific binding by 50% (IC50) correlate well (r = 0.991; P less than 0.00001) and show good numerical agreement with potencies reported for inhibition of the response to histamine in H2-mediated systems. The correlation is poorer when IC50 is replaced by either K1 (r = 0.973) or K2 (r = 0.921) for those antagonists that reveal both; the antihistaminic activity of the drug thus appears not to be associated preferentially with one or other class of sites. Since F2 varies from 0.16 to 0.60 among those antagonists that discern heterogeneity, the antagonist appears to determine the distribution of sites between the two classes. Moreover, a correlation among antagonists between values of K1 and K2 (r = 0.975; P = 0.00001) suggests that the apparent heterogeneity reflects different conformers within an otherwise homogeneous population. H2 antagonists appear to be noncompetitive with respect to each other and to the radioligand: one antagonist has relatively little effect on the values of K1, K2, and F2 revealed by another; also, estimates of K1 and K2 are independent of the concentration of [3H]histamine between 1.3 and 10 nM, although the radioligand exhibits an apparent dissociation constant of 3.9 nM [Steinberg, G. H., Eppel, J. G., Kandel, M., Kandel, S. I., & Wells, J. W. (1985) Biochemistry (preceding paper in this issue)].

H2 histaminic receptors in rat cerebral cortex. 1. Binding of [3H]histamine.

Saturable binding of [3H]histamine in equilibrium with homogenates of rat cerebral cortex reveals Hill coefficients between 0.4 and 1.0, depending upon the conditions. Data from individual experiments are well described assuming one or two classes of sites. Only the sites of higher affinity (KP1 = 3.9 +/- 0.5 nM) are observed when binding is measured by isotopic dilution at a low concentration of the radioligand (less than 1.5 nM) in the presence of magnesium or by varying the concentration of the radioligand. The sites of lower affinity (KP2 = 221 +/- 26 nM) appear during isotopic dilution at higher concentrations of the radioligand or at lower concentrations either upon the addition of guanylyl imidodiphosphate (GMP-PNP) or upon the removal of magnesium. Estimates of the second- and first-order rate constants for association and dissociation of [3H]histamine agree well with KP1. Apparent capacities corresponding to KP1 and KP2 are of the order of 100 ([R1]t) and 1300 pmol/g of protein ([R2]t), respectively. Simple interconversion cannot account for the changes in binding that occur upon adding GMP-PNP or removing magnesium, since the increase in [R2]t exceeds the decrease in [R1]t. Moreover, the apparent amount of high-affinity complex exhibits a biphasic dependence on the concentration of [3H]histamine; an increase at low concentrations is offset by a decrease that occurs at higher concentrations. The latter appears to be positively cooperative and concomitant with formation of the low-affinity complex. These and other observations indicate that the binding of histamine is inconsistent with models commonly invoked to rationalize the binding of agonists to neurohumoral receptors. GMP-PNP and magnesium reciprocally alter capacity at the sites of higher affinity, however, and the reduction caused by GMP-PNP reflects a substantial increase in the rate constant for dissociation at the sites that appear to be lost. The sites labeled by [3H]histamine thus reveal the properties of neurohumoral receptors linked to a nucleotide-specific G/F protein.

H2 histaminic receptors in rat cerebral cortex. 3. Inhibition of [3H]histamine by H2 agonists.

The binding of [3H]histamine to H2 receptors in homogenates of rat cerebral cortex is inhibited by 11 H2 agonists in a characteristic and unique manner. At low concentrations of the radioligand (less than 1.5 nM), the inhibitory profiles of individual agonists (A) are distinctly biphasic; specific binding is well described in most cases by the empirical expression Y = F1K1/(K1 + [A]) + F2K2/(K2 + [A]), in which F1 and F2 sum to 1. Maximal inhibition is the same for all agonists. Since values of F2 vary from 0.42 to 0.90, the agonist appears to determine the equilibrium distribution of receptors between two states of affinity. Ratios of apparent affinity (K2/K1) vary from 204 to 3 090 000, and there is no correlation between values of K1 and K2. Compounds lacking H2 activity, including structural analogues of histamine and dimaprit, reveal a Hill coefficient of 1 and inhibit the radioligand only weakly. For six agonists, values of K2 agree and correlate well (P = 0.00047) with H2 pharmacological potency (EC50) in the guinea pig right atrium; for the others, K2 is less than EC50 by 15-61-fold. Four observations suggest that the inhibition corresponding to F1 is allosteric and cooperative: the dissociation constant of the radioligand appears to vary in the presence of an unlabeled agonist, absolute levels of binding corresponding to F1, as defined by dimaprit, decrease at higher concentrations of [3H]histamine, F1 for dimaprit is reduced from 0.48 to 0.32 by 2-methylhistamine (F1 = 0.27) at a concentration of 20 nM (approximately K1(0.5) K2(0.5) for 2-methylhistamine), but the increase in K1 for dimprit is at least 100-fold less than expected from competitive effects, and 1 equiv of some agonists appears to preclude access of [3H]histamine to more than 1 equiv of receptors, with no evidence that an appreciable fraction of the unlabeled drug is bound. Noncompetitive effects also may account in part for the inhibition corresponding to F2.

Carbonic anhydrase from spinach leaves. Isolation and some chemical properties.

Spinach carbonic anhydrase has been purified by modification and extension of a published method (Pocker, Y., and Ng. J. S. U. (1973) Biochemistry 12, 5127-5134), using (NH4)2SO4 precipitation and chromatography on DEAE-cellulose, agarose, and DEAE-Sephadex. The enzyme so obtained was homogeneous by criteria of both standard and sodium dodecyl sulfate polyacrylamide gel electrophoresis and of constant specific activity throughout the elution profile on DEAE-Sephadex chromatography. The enzyme has an apparent Mr of 212,000 by gel filtration on Sephadex G-200, a Mr of 26,000 by sodium dodecyl sulfate electrophoresis, and each of the subunits contains approximately 1 g atom of zinc. These data and the excellent correlation between the number of lysine and arginine residues per subunit, and the number of tryptic peptides obtained by peptide mapping, suggest that spinach carbonic anhydrase is an octamer consisting of identical or very similar subunits. Its amino acid composition is similar to parsley carbonic anhydrase; both contain large numbers of half-cystine residues relative to erythrocyte carbonic anhydrases. The spinach enzyme is devoid of disulfide bonds. The enzyme is stable around neutrality at -14 degrees, as a suspension in saturated (NH4)2SO4 solution.

The esterase activity of bovine carbonic anhydrase B above pH 9. Reversible and cooalent inhibition by acetozolamide.

The reversible complex between the metalloenzyme bovine carbonic anhydrase B and the sulfonamide inhibitor acetazolamide can be "frozen" irreversibly by the addition of a covalent bond between the methyl group of the inhibitor and the tau-nitrogen of histidine-64. In both cases the inhibited enzyme is inactive as an esterase toward p-nitrophenyl propionate at physiological pH but retains activity controlled by an ionization in the protein exhibiting a pK-a greater than 10. Similarly, both the covalently and reversibly inhibited enzymes in which the catalytically essential Zn(II) ion has been replaced with Co(II) display the same visible absorption spectrum which is invariant over the pH range from 5 to 12. The evidence therefore indicates that the position of the acetazolamide moiety in the active site is independent of both pH and the presence of the covalent bond to histidine-64. Moreover, when reversibly bound, this inhibitor has been shown to replace the water molecule (or hydroxide ion) known to occupy the fourth coordination position of the metal ion and frequently implicated in the catalytic mechanism of carbonic anhydrases. Thus, the activity exhibited by the inhibited enzymes and consequently the second rise observed in the pH rate profile of the native enzyme above pH 0 cannot reflect the ionization of such a water molecule in contrast to what has been postulated previously (Pocker, Y., and Storm, D. R. (1968) Biochemistry 7, 1202-1214). Displacement of the zinc-bound solvent molecule rather than the alkylation of histidine-64 is suggested, however, as the cause of the inactivation of the alkylated enzyme round neutrality. Taken together, the biphasic pH rate profile of native bovine carbonic anhydrase B as well as the activity retained by the alkylated enzyme above pH 9 are best described by a model in which two groups in the enzyme ionize independently, thereby raising the possibility that the high pH activity is controlled by an ionization outside the active site region of the enzyme. Above pH 9.5 the pK; for the reversible interaction between native carbonic anhydrase and acetazolamide falls off linearly with increasing pH. The slope of --1.56 suggests that, among other factors, more than one ionization is responsible for the descending limb of the pH-i-pH profile.

Photooxidation of dinitrophenylhistidine-200 human carbonic anhydrase B.

Partial inactivation of tau-dinitrophenylhistidine-200 human carbonic anhydrase B, induced by visible light, followed first order kinetics (k(app) = 6.05 times 10-2 min-1). After 50 min the tau-dinitrophenylhistidine (tau-DNP-histidine) content decreased to a negligible level, but the illuminated enzyme retained, at pH 7.6, approximately 9.2 percent of the esterase activity of the native enzyme. The following lines of evidence suggest that the loss of activity results from the destruction of tau-DNP-histidine-200. (1) No significant loss of amino acid other than tau-DNP-histidine was detected after illumination. (2) The rate of loss of activity correlated well with the loss of tau-DNP-histidine. (3) In the photooxidized enzyme the DNP moiety was retained but had lost the characteristic sensitivity of tau-DNP-histidine to nucleophilic attack. Titration of the illuminated enzyme with acetazolamide indicated that the residual activity is an intrinsic property of the modified enzyme. The chromatographically purified photooxidized enzyme migrated as a single band on isoelectrofocusing in polyacylamide gel, and at pH 7.6 possessed 7.5 percent esterase activity relative to the native enzyme. By establishing effective destruction of histidine-200, it can be concluded that neither the pi N nor, as previously shown, the tau N of histidine-200 is critical for the catalysis.