To reduce cytotoxicity when testing the virucidal activity of chemical disinfectants and biocides: The "T-25 method" as an alternative to "large-volume-plating"

When testing the virucidal activity of biocides, the non-inactivated residual virus is titrated on cell cultures by the end point dilution method on 96-well tissue culture plates. However, residues of the biocide to be tested also come into contact with the cell cultures in varying concentrations and thus can lead to cytotoxic effects even at high levels of dilution. In the European standards for testing biocides, in particular disinfectants, methods such as Large-Volume-Plating (LVP) method and, in some guidelines, gel filtration procedures are described for reducing cytotoxic effects in the case of highly cytotoxic products, if the classical dilution method proves to be impractical. In order to enable the testing of highly cytotoxic biocides for their activity against viruses, an alternative method for reducing cytotoxicity is introduced, which is based on a procedure of isolating infectious viruses from cytotoxic patients' materials such as stool and can be applied when the other methods fail.

Functional assessments for decision-making regarding return to sports following ACL reconstruction. Part II: clinical application of a new test battery

PURPOSE

The purpose of this study was to utilize a novel functional test system to facilitate determining the time of return to sports following ACL reconstruction.

METHODS

Sixty-nine patients with unilateral ACL reconstruction were included in this pilot study. All the patients performed a standardized test battery consisting of one- and two-legged stability tests, counter movement jumps, speedy jumps, plyometric jumps and a quick feed test. The first test was administered on average 170.7 ± 75.1 days post-operatively, and the retest was administered on average 239.1 ± 79.7 days post-operatively. The values of the subtests were compared with the normative data of healthy gender- and age-matched controls to determine the functional capacities of patients following ACL reconstruction.

RESULTS

After the first and second test, 15.9 and 17.4 % of the patients met the criteria for a "return to non-competitive sports". One patient fulfilled the criteria for a "return to competitive sports" after the second test battery. The most limiting factor was a poor LSI value of <90 % if the dominant leg was involved and <80 % if the non-dominant leg was involved.

CONCLUSION

This test battery demonstrates that, in terms of neuromuscular abilities, most patients, compared to healthy controls, are most likely not ready for a safe return to sports, even 8 months post-operatively. This should be considered in the future to determine when it is safe to return to sports and should avoid a premature return to competitive sports.

LEVEL OF EVIDENCE

III.

[The assessment of biological maturation for talent selection - which method can be used?]

BACKGROUND

The biological maturity status plays an important role in sports, since it influences the performance level and the talent selection in various types of sport. More mature athletes are favorably selected for regional and national squads. Therefore, the biological maturity status should be considered during the talent selection process. In this context, the relative age effect (RAE), which exists when the relative age quarter distribution of selected sports groups shows a biased distribution with an over-representation of athletes born in the first months after the specific cut-off-date for the competition categories, represents another problem in the talent development. From an ethical point of view, discrimination of young talented kids does exist: the relatively younger athletes have little to no chance of reaching the elite level, despite their talents and efforts. The causal mechanisms behind the RAE are still unclear and have to be assessed. In this context, the biological maturation seems to be a possible influential factor for the existence of a RAE in sport, which has to be examined. Several methods for estimating the biological maturity status exist; however, they are often expensive and not practicable. Consequently, the aim of the present study was to assess the concordance of a simple, yet accurate method of estimating biological maturation (prediction equation of age at peak height velocity, APHV) of Mirwald and co-workers, and the gold standard method of estimating skeletal age (SA, the x-ray of the left wrist).

METHODS

In total, 75 Austrian students (40♂, 35♀) aged 10 - 13 years, were examined. Thirty of the participants (17♂, 13♀) were students of a well-known Austrian ski boarding school, and 45 (23♂, 22♀) of a non-sportive secondary modern school of the same region. The participants included in the study had not experienced a rupture of the carpal bones of the left wrist. Parents and participants were informed of the study aims, requirements and risks before providing written informed consent. The study was performed according to the Declaration of Helsinki. The study was approved by the Board for Ethical Questions in Science (Nr.: 2/2014) and the Institutional Ethics Review Boards for Human Research. For the prediction equations, the body height, the body mass and the sitting height were examined 8. The actual CA at time of measurement, and the leg length as the difference between body height and sitting height were calculated. These parameters were used to predict MO as time before or after PHV for boys and girls using the prediction equations of Mirwald et al. 19. According to Malina and Koziel 8, the participants were classified as late, on time (average) or early maturing on the basis of their APHV relative to the sample mean and standard deviation separated by sex. Participants within plus/minus the standard deviation of the mean were considered on time; participants with APHV > mean + standard deviation were classified late, while those with APHV < mean - standard deviation were classified early. An expert in pediatric endocrinology evaluated the x-rays of the left-hand wrist with the Greulich-Pyle-Method for assessing SA, the most widely used method of determining SA 24. The difference between SA and CA were calculated (= difference SA-CA). Consistent with other studies, the participants were divided into three groups according to their maturity status: on time or average maturity status was a SA within ±1 year of CA, late maturating was a SA behind CA of more than 1 year, and early maturating was a SA in advance of CA of more than 1 year 5 19 25. The most accurate method used to compare two methods of measurement is the Bland-Altman plot and the 95 % limits of agreement 26 27 28. Bland-Altman plots of the difference between difference in APHV (from the literature mean) and difference SA-CA (y-axis) and the mean of difference in APHV and difference SA-CA (x-axis) were performed. Approximately 95 % of the points in the plot should lie within the limits; then the concordance between the two methods of measurement is given 28. Additionally, intraclass correlation coefficients (ICC(3,1); two-way-mixed, total agreement) were calculated between difference in APHV and difference SA-CA. Chi²-tests were used to assess the difference in the percentage of pupils classified as on time, early or late maturing between the classifications based on the SA and on APHV, respectively. The level of significance was set at p < 0.05 and for highly significant at p < 0.01. All of the calculations were performed using PASW Statistics V.21.0.

RESULTS

Chi²-tests did not show any significant differences (p = 0.404) in the percentage of participants classified as on time, early or late maturing between the two classifications based on SA and on APHV, respectively, neither for the total sample, nor for the two groups ski racers and non-athletes. The Bland-Altman analysis showed that more than 95 % of the points in the plot lie within the limits; consequently, there is concordance between the two methods with regard to estimating biological maturation. The ICC(3,1) statistics showed a highly significant correlation: p = 0.002, ICC (95 % CI) = 0.48 (0.13 - 0.69).

CONCLUSIONS

The prediction equations to determine APHV seem to be a valid method of assessing the biological maturity status of youths aged 10 - 13 years. The percentage of pupils classified as on time, early or late maturing did not differ significantly between the classifications based on the two methods. Also the Bland-Altman analysis proved the concordance between the two methods. The RAE could be influenced and strengthened by the biological age in sports in which advantages in maturity parameters are important. Athletes born early in the selection year, who are also at the same time advanced in maturity, might be advantaged in the selection process. However, since the prediction equations seem to be valid, this method can be used in the future in the talent selection process in order to not disadvantage late-maturing athletes, which in turn could result in the reduction of the occurrence of the RAE in various types of sports in the future. In talent selection processes the growth spurt and the implemented changes in proportions between core and the extremities are often not considered; although it was shown that during this period, athletes showed poor performances in physical fitness. Since physical fitness is an important criterion in talent selection processes, athletes who go through their individual peak growth spurt at the time of selection have disadvantages due to the diverse proportions. As a consequence, it seems important to know the athlete's APHV in order to consider the variations in physical performance caused by developmental changes. The prediction equations to determine APHV include the leg length and sitting height in order to consider the diverse proportions between core and extremities; hence, this method seems to be accurate and should be implemented in the talent selection process.

NF449: a subnanomolar potency antagonist at recombinant rat P2X1 receptors

Antagonistic effects of the novel suramin analogue 4,4',4",4"'-(carbonylbis(imino-5,1,3-benzenetriylbis(carbonylimino)))tetrakis-benzene-1,3-disulfonic acid (NF449) were studied on contractions of the rat vas deferens elicited by alpha,beta-methylene ATP (alphabetameATP; mediated by P2X1 receptors), contractions of the guinea-pig ileal longitudinal smooth muscle elicited by alphabetameATP (mediated by P2X3 receptors) or adenosine 5'-O-(2-thiodiphosphate) (ADPbetaS; mediated by P2Y1 receptors), ATP-induced increases of [Ca2+]i in human embryonic kidney (HEK) 293 cells (mediated by P2Y2 receptors), inward currents evoked by ATP in follicle cell-free Xenopus laevis oocytes expressing rP2X1 or rP2X3 receptors and degradation of ATP by ecto-nucleotidases in folliculated Xenopus laevis oocytes. In addition, NF449 was examined for its P2 receptor specificity in rat vas deferens (alpha1A-adrenoceptors) and guinea-pig ileum (histamine H1 and muscarinic M3 receptors). At native (pIC50=7.15) and recombinant (pIC50=9.54) P2X1 receptors, NF449 was a highly potent antagonist. The P2X3 receptors present in guinea-pig ileum (pIC50=5.04) or expressed in oocytes (pIC50 approximately 5.6) were much less sensitive for NF449. It also was a very weak antagonist at P2Y1 receptors in guinea-pig ileum (pIC50=4.85) and P2Y2 receptors in HEK 293 cells (pIC50=3.86), and showed very low inhibitory potency on ecto-nucleotidases (pIC50<3.5). NF449 (100 microM) did not interact with alpha1A-adrenoceptors or histamine H1 and muscarinic M3 receptors. Thus, the antagonism by NF449 is highly specific for P2 receptors. In conclusion, the subnanomolar potency at rP2X1 receptors and the rank order of potency, P2X1 >> P2X3 > P2Y1 > P2Y2 > ecto-nucleotidases, make NF449 unique among the P2 receptor antagonists reported to date. NF449 may fill the long-standing need for a P2X1-selective radioligand.

The novel heteromeric bivalent ligand SB9 potently antagonizes P2Y(1) receptor-mediated responses

Effects of 6-[(4,6,8-trisulfo-1-naphthyl)iminocarbonyl-1, 3-(4-methylphenylene)iminocarbonyl-1, 3-phenylene-azo]-pyridoxal-5'-phosphate (SB9), a heterodimeric bivalent ligand consisting of pyridoxal-5'-phosphate and the suramin monomer, were studied on contractions of the rat vas deferens elicited by alpha beta-methylene ATP (alpha beta meATP; mediated by P2X(1)-like receptors), contractions of the guinea-pig ileal longitudinal smooth muscle elicited by adenosine 5'-O-(2-thiodiphosphate) (ADP beta S mediated by P2Y(1)-like receptors), and the degradation of ATP by ecto-nucleotidases in folliculated Xenopus laevis oocytes. SB9 (0.1-10 microM) antagonized contractile responses produced by alpha beta meATP or ADP beta S in a concentration-dependent manner. Schild analysis yielded linear regression lines of unit slope, indicating competitive antagonism. From the rightward shifts of the agonist concentration-response curves pA(2) values of 6.05+/-0.13 (vas deferens) and 6.98+/-0.07 (ileum) were derived. In both preparations, SB9 behaved as a slow onset, slow offset antagonist. Incubation of three oocytes in the presence of ATP produced an increase in inorganic phosphate (P(i)) over a 30-min period, which amounted to 35.1+/-1.9 microM P(i) from 100 microM ATP. SB9 (10-1000 microM) reduced this degradation (pIC(50)=4.33+/-0.10). The results illustrate that SB9 is a high-affinity P2Y(1) receptor antagonist with a remarkable selectivity for P2Y(1) vs. P2X(1) receptors (about 10-fold) and ecto-nucleotidases (447-fold). These properties make it unique among the pyridoxal-5'-phosphate and suramin derivatives reported to date.

The novel pyridoxal-5'-phosphate derivative PPNDS potently antagonizes activation of P2X(1) receptors

Pyridoxal-5'-phosphate-6-(2'-naphthylazo-6'-nitro-4',8'-disulfonat e) (PPNDS) potently antagonized P2X(1) receptor-mediated responses in rat vas deferens (pK(B)=7.43) and Xenopus laevis oocytes (pIC(50)=7. 84). It showed lower (up to 20,000-fold) inhibitory potency on ecto-nucleotidase in Xenopus oocytes and on P2Y(1) receptors in guinea-pig ileum (pA(2)=6.13). PPNDS did not interact with alpha(1A)-adrenoceptors, adenosine A(1) and A(2B), histamine H(1) and muscarinic M(3) receptors. Thus, PPNDS is a novel, specific P2 receptor antagonist and represents the pyridoxal-5'-phosphate derivative with the highest potency at P2X(1) receptors.

Muscarinic properties of compounds related to arecaidine propargyl ester

A series of new analogues of the arecaidine propargyl ester (CAS 35516-99-5), APE, 1a) with alcohols consisting of 4 or 5 carbon atoms were investigated at muscarinic receptor subtypes. The muscarinic activity of the quaternary and tertiary salts of the APE-related compounds were assayed on the isolated guinea-pig ileum (M3 receptor subtype) and guinea-pig left atria (M2 receptor subtype) as well as on rabbit isolated vas deferens (M1 receptor subtype). The structural variations made in the APE molecule, replacing the triple bond in the ester side chain with structures such as double bond, an allene moiety, a single bond, a cyclopropyl group or two triple bonds should alter the selectivity and potency in favour of the M2 subtype. Enhanced, though modest, selectivity for M2 receptors was achieved with the 2-butynyl ester 2a. The other structural variations resulted in a loss of potency, but not necessarily of efficacy.

The design and pharmacology of novel selective muscarinic agonists and antagonists

The muscarinic pharmacology of C1-methyl-substituted chiral compounds related to McN-A-343 and of (R)- and (S)-dimethindene has been studied. Among the McN-A-343 analogues, the (S)-enantiomers were more potent and had higher affinity than the (R)-isomers. The quaternary compound (S)-BN 228 was found to be the most potent M1-selective agonist known today (pEC50: M1/rabbit vas deferens = 7.83; M2/guinea-pig atria = 6.35; M3/guinea-pig ileum = 6.29). In both the atria and ileum the tertiary carbamate, (S)-4-F-MePyMcN, was a competitive antagonist (pA2 value = 7.39 and 6.82, respectively). In contrast, in rabbit vas deferens (S)-4-F-MePyMcN was a potent partial agonist (pEC50 = 7.22; apparent efficacy = 0.83). These results indicate that (S)-4-F-MePyMcN might be a useful tool to study M1 receptor-mediated effects involved in central cholinergic function. (S)-Dimethindene was a potent M2-selective antagonist (pA2 = 7.86/atria; pKi = 7.8/rat heart) with lower affinities for the M1 (pA2 = 6.36/rat duodenum; pKi = 7.1/NB-OK 1 cells), M3 (pA2 = 6.92/guinea-pig ileum; pKi = 6.7/rat pancreas) and M4 receptors (pKi = 7.0/rat striatum). It was more potent (up to 41-fold) than the (R)-isomer. In contrast, the stereoselectivity was inverse at ileal H1 receptors (pA2: (R)-isomer = 9.42; (S)-isomer = 7.48). Thus, (S)-dimethindene could be a valuable agent to test the hypothesis that M2 antagonists show beneficial effects in the treatment of cognitive disorders. It might also become the starting point for the development of diagnostic tools for quantifying M2 receptors in the CNS with PET imaging.

Children's judgements about psychological harm in social context

72 children, ages 6 to 11 years, were presented with a series of stories involving psychological harm (name-calling) in a game context. Situations were presented in which intentions, consequences, and game context were varied, along with order of story presentation. Comparison between acts of physical and psychological harm were also conducted. Although responses in some conditions were influenced by order of presentation, age differences were found in children's evaluations of agents' actions and recipients' reactions for psychological harm in game contexts. Younger children were more likely to ignore intentions and consequences or the recipient's perspective and to focus on contextual features (e.g. game rules). Older children were more likely to base their evaluations on intentions, or both intentions and consequences, and to take into account the recipient's perspective. Game context interacted differentially with psychological and physical harm at all ages. Evaluations of acts of physical harm were more likely than acts of psychological harm to be transformed by game context.

The (S)-(+)-enantiomer of dimethindene: a novel M2-selective muscarinic receptor antagonist

The present study was designed to determine to determine the in vitro affinity profile of (R)-(-)-dimethindene and (S)-(+)-dimethindene at muscarinic receptor subtypes using both functional and binding assays. In addition, the racemate was investigated in functional studies. The functional muscarinic receptors studied were putative M1 receptors in rabbit vas deferens and rat duodenum, M2 receptors in guinea-pig left atria and rabbit vas deferens, as well as M3 receptors in guinea-pig ileum and trachea. Furthermore, the histamine H1 antagonism by (R)-(-)- and (S)-(+)-dimethindene has been examined in guinea-pig ileum. Muscarinic binding selectivity was assessed in homogenates from human neuroblastoma NB-OF 1 cells (M1), rat heart (M2), pancreas (3) and striatum (M4). The results demonstrate that (S)-(+)-dimethindene is a potent M2-selective muscarinic receptor antagonist (pA2 = 7.86/7.74; pKi = 7.78) with lower affinities for the muscarinic M1 (pA2 = 6.83/6.36; pKi = 7.08), the M3 (pA2 = 6.92/6.96; pKi = 6.70) and the M4 receptors (pKi = 7.00), respectively. The (S)-(+)-enantiomer was more potent (up to 41-fold) than the (R)-(-)-enantiomer in all muscarinic assays. In contrast, the stereoselectivity was inverse at histamine H1 receptors, the (R)-(-)-enantiomer being the eutomer (pA2 = 9.42; pA2/(S)-isomer = 7.48). In conclusion, (S)-(+)-dimethindene is a useful tool to investigate muscarinic receptor heterogeneity. In addition, this lipophilic compound might become the starting point for the development of M2-selective muscarinic receptor antagonists useful as diagnostic tools for quantifying muscarinic M2 receptors in the central nervous system with positron emission tomography imaging, and to test the hypothesis that muscarinic M2 receptor antagonists show beneficial effects in the treatment of cognitive disorders.

New functionally selective muscarinic agonists

The muscarinic pharmacology of two novel agonists related to McN-A-343, 4-F-PyMcN and 4-F-PyMcN+, has been studied by the use of pharmacological and radioligand binding techniques. Both compounds were potent agonists at M1 receptors in rabbit vas deferens (pEC50 = 6.24 and 6.96) and rat duodenum (pEC50 = 5.47 and 6.38), but very weak partial agonists or competitive antagonists at guinea-pig cardiac M2 and ileal M3 receptors. There was no receptor reserve for 4-F-PyMcN in rabbit vas deferens, for which the potency (pEC50 = 6.24) and apparent affinity (pKA = 5.99 and 6.21) were similar. 4-F-PyMcN+ showed only limited binding selectivity between four muscarinic receptor binding assays with apparent affinity constants (pKi) of 5.8, 5.2, 5.6 and 5.7 for M1, M2, M3 and M4 muscarinic receptor subtypes. The two novel functionally M1-selective agonists may provide useful tools with which to study muscarinic receptor mechanisms. The non-quaternary compound, 4-F-PyMcN, might become a starting point for the development of drugs that selectively affect M1 receptors involved in central cholinergic function.

PPADS, a novel functionally selective antagonist of P2 purinoceptor-mediated responses

We have characterized PPADS (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid) as a novel antagonist which selectively blocks P2 purinoceptor-mediated responses in rabbit vas deferens at pre- and postjunctional sites. PPADS did not interact with alpha 1-adrenoceptors, muscarinic M2 and M3 receptors, histamine H1 and adenosine A1 receptors. Thus, PPADS is a novel and useful pharmacological tool to study co-transmission in tissues where ATP and co-existing neurotransmitters act in concert.

Competition between photobleaching and fluorescence increase of photosensitizing porphyrins and tetrasulphonated chloroaluminiumphthalocyanine

The time-dependent fluorescence changes of photosensitizing porphyrins and tetrasulphonated chloroaluminiumphthalocyanine (A1C1SPc) were measured at different intracellular sites using video-enhanced microscopy and image processing. To obtain variations in intracellular fluorescence intensity, different radiant exposures of a Kr+ laser-pumped dye laser were delivered via a 600 microns plastic-clad silica fibre connected to the microscope. During irradiation, competition between photobleaching and fluorescence increase of the different dyes was observed. The porphyrins normally showed photobleaching, which was dependent on the sensitizer and its specific accumulation within the cell. Photobleaching was less pronounced for hydrophilic uroporphyrin than for more hydrophobic dyes. In contrast with an almost exponential decrease in porphyrin fluorescence with increasing light dose, the fluorescence intensity of A1C1SPc significantly increased at the beginning of irradiation, and could be correlated with intracellular deaggregation.