Median effective dose of 0.2% ropivacaine for ultrasound-guided median nerve block in young children

OBJECTIVE

To determine the median effective dose (ED₅₀) and the 95% effective dose (ED₉₅) of 0.2% ropivacaine for ultrasound-guided lower forearm median nerve block in paediatric patients.

METHODS

Eligible children were American Society of Anesthesiologists (ASA) status I-II scheduled to have elective open surgery for trigger thumb repair. Patients were stratified into two age groups: 1- to 3-year-olds and 3- to 6-year-olds. The ED₅₀ was determined by Dixon's up-and-down method. The first patient received an ultrasound-guided median nerve block by injection of 2 mL of 0.2% ropivacaine. Each subsequent patient's dose was determined by the response of the previous patient, the doses being adjusted in intervals of 0.2 mL. In addition, the 95% effective dose (ED₉₅) was obtained using a probit regression approach. The patients' general condition, postoperative pain scores, and adverse events were recorded.

RESULTS

A total of 52 children who were scheduled to undergo open surgery for trigger thumb were included in this study: 28 in the 1- to 3-year-olds group and 24 in the 3- to 6-year-olds group. The ED₅₀ (95% confidence interval) values were 0.9 (0.44-1.36) mL in 1- to 3-year-olds and 1.4 (1.14-1.66) mL in 3- to 6-year-olds. The ED₉₅ (95% confidence interval) values were 1.5 (0.98-1.58) mL in 1- to 3-year-olds and 1.7 (1.54-1.78) mL in 3- to 6-year-olds. No adverse events occurred.

CONCLUSIONS

A single dose of ropivacaine was an effective agent for young children requiring ultrasound-guided lower forearm median nerve block in open surgery for trigger thumb. The ED₅₀ (95% confidence interval) values were 0.9 (0.44-1.36) mL in 1- to 3-year-olds and 1.4 (1.14-1.66) mL in 3- to 6-year-olds. The ED₉₅ (95% confidence interval) values were 1.5 (0.98-1.58) mL in 1- to 3-year-olds and 1.7 (1.54-1.78) mL in 3- to 6-year-olds.

Optimization of chitosan nanoparticle synthesis and its potential application as germination elicitor of Oryza sativa L

The worldwide rice production has been dwindling due to biotic and abiotic causes. Chitosan is a proven biofunctional material that induces many biological responses in plants. However, the growth and yield increasing properties of chitosan nanoparticles (ChNP) on rice crop are not well understood. In the present work, effect of ChNP on germination of rice has been studied. Seed toxicity of ChNP was also analyzed to ensure the safety of ChNP application. The toxicity study was done according to EPA guidelines and ChNP was found to be non-toxic. Rice seeds were treated with ChNP at different concentrations for different time periods and kept for germination. Upon complete germination, the seedlings were sown in seed trays and growth was evaluated at 21 days after sowing. All treatments showed better results than the untreated control. Treatment T₂₂ (1 mg/ml ChNP for 120 mins) gave the highest growth rates. Therefore we could deduce that ability of ChNP to elicit growth was associated with the concentration of ChNP and soaking time. The shelf life of ChNP was studied over a period of one year by analyzing the germination eliciting capacity on rice seeds. ChNP was found to effective for seven months when stored under room temperature.

Evaluating the broad-spectrum efficacy of the acetylcholinesterase oximes reactivators MMB4 DMS, HLö-7 DMS, and 2-PAM Cl against phorate oxon, sarin, and VX in the Hartley guinea pig

Organophosphorus (OP) compounds, including pesticides and chemical warfare nerve agents (CWNA), are threats to the general population as possible weapons of terrorism or by accidental exposure whether through inadvertent release from manufacturing facilities or during transport. To mitigate the toxicities posed by these threats, a therapeutic regimen that is quick-acting and efficacious against a broad spectrum of OPs is highly desired. The work described herein sought to assess the protective ratio (PR), median effective doses (ED₅₀), and therapeutic index (TI = oxime 24-h LD₅₀/oxime ED₅₀) of MMB4 DMS, HLö-7 DMS, and 2-PAM Cl against the OPs sarin (GB), VX, and phorate-oxon (PHO). All OPs are representative of the broader classes of G and V chemical warfare nerve agents and persistent pesticides. MMB4 DMS and HLö-7 DMS were previously identified as comparative efficacy leads warranting further evaluations. 2-PAM Cl is the U.S. FDA-approved standard-of-care oxime therapy for OP intoxication. Briefly, PRs were determined in male guinea pigs by varying the subcutaneously (SC) delivered OP dose followed then by therapy with fixed levels of the oxime and atropine (0.4 mg/kg; administered intramuscularly [IM]). ED₅₀s were determined using a similar approach except the OP dose was held constant at twice the median lethal dose (2 × LD₅₀) while the oxime treatment levels were varied. The ED₅₀ information was then used to calculate the TI for each OP/oxime combination. Both MMB4 DMS and HLö-7 DMS provided significant protection, i.e., higher PR against GB, VX, and PHO when compared to atropine controls, but significance was not readily demonstrated across the board when compared against 2-PAM Cl. The ED₅₀ values of MMB4 DMS was consistently lower than that of the other oximes against all three OPs. Furthermore, based on those ED₅₀s, the TI trend of the various oximes against both GB and VX was MMB4 DMS > HLö-7 DMS > 2-PAM Cl, while against PHO, MMB4 DMS > 2-PAM Cl > HLö-7 DMS.

Proteomics, functional characterization and antivenom neutralization of the venom of Pakistani Russell's viper (Daboia russelii) from the wild

The venom proteome of wild Pakistani Russell's viper (Daboia russelii) was investigated through nano-ESI-LCMS/MS of the reverse-phase HPLC fractions. A total of 54 venom proteins were identified and clustered into 11 protein families. Phospholipase A2 (PLA2, 63.8%) and Kunitz-type serine protease inhibitor (KSPI, 16.0%) were most abundant, followed by snake venom serine protease (SVSP, 5.5%, mainly Factor V activating enzyme), vascular endothelial growth factor (VEGF, 4.3%), snake venom metalloproteinase (SVMP, 2.5%, mainly Factor X activating enzyme) and phosphodiesterase (PDE, 2.5%). Other minor proteins include cysteine-rich secretory protein (CRiSP), snake venom C-type lectin/lectin-like protein (snaclec), nerve growth factor, L-amino acid oxidase and 5'-nucleotidase. PLA2, KSPI, SVSP, snaclec and SVMP are hemotoxic proteins in the venom. The study indicated substantial venom variation in D. russelii venoms of different locales, including 3 Pakistani specimens kept in the USA. The venom exhibited potent procoagulant activity on human plasma (minimum clotting dose = 14.5 ng/ml) and high lethality (rodent LD50 = 0.19 μg/g) but lacked hemorrhagic effect locally. The Indian VINS Polyvalent Antivenom bound the venom immunologically in a concentration-dependent manner. It moderately neutralized the venom procoagulant and lethal effects (normalized potency against lethality = 2.7 mg venom neutralized per g antivenom).

BIOLOGICAL SIGNIFICANCE

Comprehensive venom proteomes of D. russelii from different locales will facilitate better understanding of the geographical variability of the venom in both qualitative and quantitative terms. This is essential to provide scientific basis for the interpretation of differences in the clinical presentation of Russell's viper envenomation. The study revealed a unique venom proteome of the Pakistani D. russelii from the wild (Indus Delta), in which PLA2 predominated (~60% of total venom proteins). The finding unveiled remarkable differences in the venom compositions between the wild (present study) and the captive specimens reported previously. The integration of toxicity tests enabled the correlation of the venom proteome with the envenoming pathophysiology, where the venom showed potent lethality mediated through coagulopathic activity. The Indian VINS Polyvalent Antivenom (VPAV) showed binding activity toward the venom protein antigens; however the immunorecognition of small proteins and PLA2-dominating fractions was low to moderate. Consistently, the antivenom neutralized the toxicity of the wild Pakistani Russell's viper venom at moderate efficacies. Our results suggest that it may be possible to enhance the Indian antivenom potency against the Pakistani viper venom by the inclusion of venoms from a wider geographical range including that from Pakistan into the immunogen formulation.

Logit-log evaluation of planar yeast estrogen screens

Receptor assays like the yeast estrogen screen (YES) performed in microtiter plates normally provide dose-response curves with a sigmoidal shape in semi-log plots. Such sigmoidal plots can be linearized by the logit function resulting in logit-log plots, as mainly known for the evaluation of enzyme-linked immunosorbent assays and radioimmunoassays. Since the planar yeast estrogen screen (pYES) represents the transfer of the receptor assay YES to high-performance thin-layer chromatography (HPTLC), it was assumed to obtain sigmoidal shaped dose-response curves from the measured signals, which subsequently could be used to generate logit-log plots. However, it was observed that typical sigmoidal curves were not obtained, when peak areas were plotted against the applied amount on a logarithmic scale (log amount). Therefore, peak heights were examined in the present study, which revealed proper dose-response curves when plotted against the log amount. The presence of sigmoidal dose-response curves from HPTLC-pYES made it possible to transform the signals into logits and, therefore, to create logit-log plots with linear correlations. The logit-log plots for the estrogen active compounds (EAC) 17β-estradiol (E2) and 17α-ethinylestradiol (EE2) provided a working range up to 500pg/zone. Applying logit-log plots, mean recovery rates for E2 and EE2 from spiked water samples (2-20ng/L) were determined to 90% and 108%, respectively, with ≤24% RSD. Moreover, the linear graphs allowed an easy determination of the half maximal effect dose (ED₅₀) of EAC, since the intersection of the graph with the abscissa represents the ED₅₀. Additionally, with the knowledge of the ED₅₀ values, the estrogenic potential of EAC in terms of estradiol equivalent factors (EEF) could be determined, resulting in 0.64 for EE2.

Adaptation of Lorke's method to determine and compare ED50 values: the cases of two anticonvulsants drugs

INTRODUCTION

We determined the median effective dose (ED50) values for the anticonvulsants phenobarbital and sodium valproate using a modification of Lorke's method. This modification allowed appropriate statistical analysis and the use of a smaller number of mice per compound tested.

METHODS

The anticonvulsant activities of phenobarbital and sodium valproate were evaluated in male CD1 mice by maximal electroshock (MES) and intraperitoneal administration of pentylenetetrazole (PTZ). The anticonvulsant ED50 values were obtained through modifications of Lorke's method that involved changes in the selection of the three first doses in the initial test and the fourth dose in the second test. Furthermore, a test was added to evaluate the ED50 calculated by the modified Lorke's method, allowing statistical analysis of the data and determination of the confidence limits for ED50.

RESULTS

The ED50 for phenobarbital against MES- and PTZ-induced seizures was 16.3mg/kg and 12.7mg/kg, respectively. The sodium valproate values were 261.2mg/kg and 159.7mg/kg, respectively.

DISCUSSION

These results are similar to those found using the traditional methods of finding ED50, suggesting that the modifications made to Lorke's method generate equal results using fewer mice while increasing confidence in the statistical analysis. This adaptation of Lorke's method can be used to determine median letal dose (LD50) or ED50 for compounds with other pharmacological activities.

Interaction of baicalin with berberine for glucose uptake in 3T3-L1 adipocytes and HepG2 hepatocytes

ETHNOPHARMACOLOGICAL RELEVANCE

Baicalin and berberine are important coexisting constituents of the combination of Radix Scutellariae and Rhizoma Coptidis, known as scutellaria-coptis herb couple (SC), which has heat clearing and detoxifying effects. The aims of the present study were to investigate the effects of the combination of baicalin+berberine on glucose uptake in 3T3-L1 adipocytes or HepG2 cells.

MATERIALS AND METHODS

Insulin-resistant adipocytes and hepatocytes models were established. Glucose consumption was assayed to evaluate the effects of berberine, baicalin, and berberine+baicalin on glucose uptake, and the interaction of baicalin with berberine for glucose uptake was evaluated in 3T3-L1 adipocytes or HepG2 cells. Moreover, the effects of baicalin on the dose-effect relationship of berberine for glucose uptake was also evaluated in 3T3-L1 adipocytes.

RESULTS

The results of the present study demonstrated that berberine increased glucose consumption in 3T3-L1 adipocytes and HepG2 hepatocytes in a dose-dependent manner. In contrast, statistical analyses indicated that baicalin (in doses up to 100μmol/L) produced no obvious effect. The effect of berberine+baicalin on glucose uptake was better than that of berberine or baicalin alone, which indicated that berberine and baicalin had the trend of synergetic effect on glucose uptake. Furthermore, these results showed that the synergistic effect occurred in a specific dose range, while the antagonistic effect was present in another dose range in the presence of 10μmol/L baicalin. Interestingly, the entire dose-response curves of berberine shifted down in the presence of 100μmol/L baicalin, and baicalin antagonised the effect of berberine on glucose uptake in 3T3-L1 adipocytes.

CONCLUSIONS

The results of the present study showed that berberine dose-dependently increased glucose consumption in 3T3-L1 adipocytes and HepG2 hepatocytes. Furthermore, interaction of baicalin with berberine was additive at low doses of baicalin and antagonistic at higher baicalin doses. Thus, it is possible that baicalin is a partial agonist. These results provided a basis for the study of the TCM compatibility mechanism and a new insight into the application for Gegen Qinlian Decoction (GGQLD) or SC in the clinic.

Tissue selectivity of ospemifene: pharmacologic profile and clinical implications

The multifactorial consequences of menopausal estrogen deficiency affect numerous tissues throughout the body. Supplemental hormonal therapies carry the burden of a risk/benefit ratio that must be highly individualized. Selective estrogen receptor modulators (SERMs) are estrogen receptor (ER) agonist/antagonists designed to induce benefits comparable with estrogen while minimizing adverse effects. Here, we review the estrogen agonist/antagonist profile of ospemifene, a novel triphenylethylene derivative recently approved to treat dyspareunia, a symptom of vulvar and vaginal atrophy (VVA) due to menopause, both preclinically and clinically. Ospemifene binds ERα and ERβ with approximately equal affinities. In preclinical models, ospemifene increased vaginal and uterine epithelial thickness and mucification to the same extent as estrogen. Ospemifene did not induce endometrial hyperplasia in animal models; there also was no stimulatory effect on endometrial cells. In rat and human mammary cells in vitro, ospemifene evokes a dose-dependent inhibition on estrogen-induced cell responses and cell proliferation, supporting an antiestrogenic effect in breast. In contrast, ospemifene has an estrogenic effect on bone, as seen by improved bone mineral density, strength, mass, and histomorphometry in preclinical models, consistent with improvements in markers of bone resorption and formation in postmenopausal women. Based on the preclinical evidence, ospemifene has beneficial estrogen-like effects on the vaginal epithelium, preliminary evidence to support a neutral endometrial profile, antiproliferative effects in breast, and estrogenic effects in bone. Taken together, especially regarding estrogen-like effects on the vaginal epithelium, ospemifene presents a profile of tissue-specific effects that appear novel among available SERMs and well-suited for the treatment of VVA.

Antidepressant-like activity of the adenosine A(2A) receptor antagonist, istradefylline (KW-6002), in the forced swim test and the tail suspension test in rodents

RATIONALE

Depression is common in Parkinson's disease (PD) but its response to classical antidepressants is not clear. The adenosine A2A antagonist istradefylline is effective in the treatment of the motor symptoms of PD but inhibition of the adenosine A2A receptor may also induce antidepressant-like effects.

OBJECTIVE

We have investigated whether istradefylline might be effective in treating depression in PD using the forced swimming test (FST) and the tail suspension test (TST) in rodents.

RESULTS

Istradefylline significantly decreased immobility time in the FST in both rats and mice (0.16mg/kg and higher) with comparable efficacy to an equivalent dose of the tricyclic antidepressants, desipramine and imipramine. Both 8-OH-DPAT (5-HT1A agonist) and quinpirole (D2 agonist) also reduced the immobility time. The istradefylline-induced reduction of immobility time was attenuated by corticosterone. In addition, the combined use of a sub-threshold dose of istradefylline and the serotonin-noradrenaline reuptake inhibitor venlafaxine ameliorated depression-like behavior in the mouse FST. In the mouse TST, istradefylline (0.08mg/kg and higher) decreased immobility time. Moreover, co-administration of istradefylline with paroxetine or fluoxetine (selective serotonin reuptake inhibitors) or deprenyl (MAO-B inhibitor) at doses that did not show antidepressant-like effects when administered alone, resulted in a significant reduction in immobility time.

CONCLUSIONS

Istradefylline alone or co-administered with currently available antidepressants, may be useful for the treatment of depression as well as motor symptoms of PD. Its effects might be, at least in part, attributable to modulation of hypothalamic-pituitary-adrenal axis.

Vaginal effects of ospemifene in the ovariectomized rat preclinical model of menopause

Ospemifene is a unique tissue-selective estrogen agonist/antagonist (also known as a selective estrogen receptor modulator [SERM]) with demonstrated efficacy in Phase 3 studies of postmenopausal women with vulvar and vaginal atrophy (VVA). This report describes preclinical studies on the effects of ospemifene in the ovariectomized (OVX) rat model of menopause. Ospemifene (10mg/kg/day) and the SERM comparator, raloxifene (10mg/kg/day) were administered for 2 weeks and both increased vaginal weight; ospemifene was more effective than raloxifene. In addition, ospemifene had a greater effect on increasing vaginal epithelial height compared with raloxifene. The effect on uterine weight was less pronounced for both ospemifene and raloxifene. The ED50 of ospemifene on vaginal epithelial height was 0.39mg/kg/day and the magnitude was nearly the same as was seen with the positive control, 17α-ethinyl estradiol (EE2). In a histological analysis of ospemifene-treated rat vaginas, basal cells were overlaid by 2 to 3 cell layers of thickened goblet-like mucified cells apically; however, the cornification observed with EE2 was absent. Estrogenic activity of ospemifene was confirmed by upregulation of progesterone receptors in vaginal epithelium and stroma. Ospemifene showed similar affinity for estrogen receptor (ER)-α and ER-β, but an overall lower affinity than estradiol. Ospemifene antagonized estrogen response element (ERE)-mediated transactivation on MCF-7 cells, confirming its anti-estrogenic activity in breast cancer cells. The dose response for ospemifene in the rat is consistent with that observed in clinical studies of ospemifene 30 and 60mg, showing that the OVX rat is a highly predictive model of SERM activity in postmenopausal VVA.

Development of an in vitro potency assay for antivenom against Malayan pit viper (Calloselasma rhodostoma)

An in vitro potency assay of antivenom against Malayan pit viper (Calloselasma rhodostoma, CR) has been developed. The assay is based on the neutralizing activity of the antivenom against the coagulant activity of the venom. The minimum coagulant dose (MCD) of CR venom was 22.12 ± 0.25 μg/ml. The coagulation time induced by 2MCD of the venom was used as the control for calculating the neutralizing activity of each batch of antivenom. The in vitro potency of antivenom, expressed as effective dose (ED), was the antivenom/venom ratio at which the coagulation time was increased three fold of that induced by 2MCD of the venom. Eleven batches of the antivenom were assayed for their lethality neutralizing activity (ED₅₀) by the in vivo assay using mice as well as the developed in vitro assay. The correlation coefficient (r) between the in vitro neutralizing activities (ED) and in vivo neutralizing activities (ED₅₀) was 0.957, (p value < 0.001). This simple and rapid in vitro assay of C. rhodostoma antivenom should be a good alternative method for the assessment of antivenom potency during the immunization program and fractionation process. The assay should be adaptable for use with antivenoms against other similar procoagulant venoms.

Omalizumab increases the intrinsic sensitivity of human basophils to IgE-mediated stimulation

BACKGROUND

Treatment of allergic patients with omalizumab results in a paradoxical increase in their basophil histamine release (HR) response ex vivo to cross-linking anti-IgE antibody. It is not known whether this change in response is associated with an increase in intrinsic cellular sensitivity, which would be a paradoxical response.

OBJECTIVE

We sought to determine whether the increase in response to anti-IgE antibody is a reflection of an increased cellular sensitivity expressed as molecules of antigen-specific IgE per basophil required to produce 50% of the maximal response.

METHODS

Patients were treated with omalizumab or placebo for 12 weeks (NCT01003301 at ClinicalTrials.gov), and the metric of basophil sensitivity was assessed at 4 time points: baseline, 6 to 8 weeks, 12 weeks (after which treatment stopped), and 24 weeks (12 weeks after the end of treatment).

RESULTS

As observed previously, treatment with omalizumab resulted in a marked increase in the maximal HR induced by cross-linking anti-IgE antibody. This change was accompanied by a marked shift in intrinsic basophil sensitivity, ranging from 2.5- to 125-fold, with an average of 6-fold at the midpoint of the treatment to 12-fold after 12 weeks. The magnitude of the increase in cellular sensitivity was inversely related to the starting sensitivity or the starting maximum HR. The increased cellular sensitivity also occurred when using leukotriene C4 secretion as a metric of the basophil response. Twelve weeks after the end of treatment, cellular sensitivity was found to shift toward the baseline value, although the return to baseline was not yet complete at this time point.

CONCLUSIONS

Treatment with omalizumab results in a markedly increased sensitivity of basophils to IgE-mediated stimulation in terms of the number of IgE molecules required to produce a given response. These results provide a better quantitative sense of the phenotypic change that occurs in basophils during omalizumab treatment, which has both mechanistic and clinical implications.

An electrochemiluminescence assay for analysis of rabies virus glycoprotein content in rabies vaccines

Vaccine potency testing is necessary to evaluate the immunogenicity of inactivated rabies virus (RABV) vaccine preparations before human or veterinary application. Currently, the NIH test is recommended by the WHO expert committee to evaluate RABV vaccine potency. However, numerous disadvantages are inherent concerning cost, number of animals and biosafety requirements. As such, several in vitro methods have been proposed for the evaluation of vaccines based on RABV glycoprotein (G) quality and quantity, which is expected to correlate with vaccine potency. In this study an antigen-capture electrochemiluminescent (ECL) assay was developed utilizing anti-RABV G monoclonal antibodies (MAb) to quantify RABV G. One MAb 2-21-14 was specific for a conformational epitope so that only immunogenic, natively folded G was captured in the assay. MAb 2-21-14 or a second MAb (62-80-6) that binds a linear epitope was used for detection of RABV G. Vaccine efficacy was also assessed in vivo using pre-exposure vaccination of mice. Purified native RABV G induced a RABV neutralizing antibody (rVNA) response with a geometric mean titer of 4.2IU/ml and protected 100% of immunized mice against RABV challenge, while an experimental vaccine with a lower quality and quantity of G induced a rVNA titer<0.05IU/ml and protected <50% of immunized mice. These preliminary results support the hypothesis that in vivo immunogenicity may be predicted from the in vitro measurement of RABV G using an ECL assay. Based upon these results, the ECL assay may have utility in replacement of the NIH test.

Pharmacodynamic modeling of cough responses to capsaicin inhalation calls into question the utility of the C5 end point

BACKGROUND

Inhaled capsaicin elicits cough reproducibly in human subjects and is widely used in the study of cough and antitussive therapies. However, the traditional end points C2 and C5 (the concentrations of capsaicin inducing at least 2 or 5 coughs, respectively) display extensive overlap between health and disease and therefore might not best reflect clinically relevant mechanisms.

OBJECTIVES

We sought to investigate capsaicin dose responses in different disease groups.

METHODS

Two novel capsaicin cough challenges were compared in patients with chronic cough (CC; n = 20), asthmatic patients (n = 18), and healthy volunteers (HVs; n = 20). Increasing doubling doses of capsaicin (0.48-1000 μmol/L, 4 inhalations per dose) were administered in challenge 1, whereas the order of the doses was randomized in challenge 2. A nonlinear mixed-effects model compared dose-response parameters by disease group and sex. Parameters were also correlated with objective cough frequency.

RESULTS

The model classified subjects based on maximum cough response evoked by any concentration of capsaicin (Emax) and the capsaicin dose inducing half-maximal response (ED50). HVs and asthmatic patients were not statistically different for either parameter and therefore combined for analysis (mean ED50, 38.6 μmol/L [relative SE, 28%]; mean Emax, 4.5 coughs [relative SE, 11%]). Compared with HVs/asthmatic patients, patients with CC had lower ED50 values (14.7 μmol/L [relative SE, 28%], P = .008) and higher Emax values (8.6 coughs [relative SE, 11%], P < .0001). Emax values highly correlated with 24-hour cough frequency (r = 0.71, P < .001) and were 37% higher in female compared with male subjects, regardless of disease group (P < .001).

CONCLUSIONS

Nonlinear mixed-effects modeling demonstrates that maximal capsaicin cough responses better discriminate health from disease and predict spontaneous cough frequency and therefore provide important insights into the mechanisms underlying CC.