The optimal atropine concentration for myopia control in Chinese children: a systematic review and network Metaanalysis

AIM:To figure out whether various atropine dosages may slow the progression of myopia in Chinese kids and teenagers and to determine the optimal atropine concentration for effectively slowing the progression of myopia.METHODS:A systematic search was conducted across the Cochrane Library,PubMed,Web of Science,EMBASE,CNKI,CBM,VIP,and Wanfang database,encompassing literature on slowing progression of myopia with varying atropine concentrations from database inception to January 17,2024.Data extraction and quality assessment were performed,and a network Meta-analysis was executed using Stata version 14.0 Software.Results were visually represented through graphs.RESULTS:Fourteen papers comprising 2475 cases were included;five different concentrations of atropine solution were used.The network Meta-analysis,along with the surface under the cumulative ranking curve(SUCRA),showed that 1%atropine(100%)>0.05%atropine(74.9%)>0.025%atropine(51.6%)>0.02%atropine(47.9%)>0.01%atropine(25.6%)>control in refraction change and 1%atropine(98.7%)>0.05%atropine(70.4%)>0.02%atropine(61.4%)>0.025%atropine(42%)>0.01%atropine(27.4%)>control in axial length(AL)change.CONCLUSION:In Chinese children and teenagers,the five various concentrations of atropine can reduce the progression of myopia.Although the network Meta-analysis showed that 1%atropine is the best one for controlling refraction and AL change,there is a high incidence of adverse effects with the use of 1%atropine.Therefore,we suggest that 0.05%atropine is optimal for Chinese children to slow myopia progression.

Atropine can induce autophagy independent of the M3 muscarinic acetylcholine receptor

Background: No other effects of atropine other than as an antagonist of muscarinic acetylcholine receptor (mAChR) have been found. Methods: In this study, human kidneyepithelial cells were treated with different physiological regulators. Results: Subsequently, it was found that atropine could significantly induce autophagy as demonstrated by the appearance of autophagosome-like double- or single-membrane vesicles in the cytoplasm ofhost cells and the number of GFP-LC3 dots. In addition, increased conversion of the autophagy marker protein LC3-I and LC3-II and increased p62/SQSTM1 indicatedincomplete autophagy. In addition, atropine induced autophagosome levels in a dose-dependent manner within a certain concentration range in human kidney epithelial cells. In atropine-treated mouse skeletal muscle cells containing nicotinic acetylcholinereceptors and rat cardiac muscle cells containing mAchR, atropine induced autophagy in mouse skeletal muscle cells but not in rat cardiac muscle cells. Furthermore, atropine did not induce autophagy in tissue cells containing mAchR in vivo but did in tissue cells not containing mAchR. Conclusion: This study expands the application and understanding of atropine’s action mechanism in the field of medicine.

Evaluation of the clinical effects of atropine in combination with remifentanil in children undergoing surgery for acute appendicitis

BACKGROUND Acute appendicitis(AA)is the most common cause of acute abdomen in children.Anesthesia significantly influences the surgical treatment of AA in children,making the scientific and effective selection of anesthetics crucial.AIM To assess the clinical effect of atropine(ATR)in combination with remifentanil(REMI)in children undergoing surgery for AA.METHODS In total,108 cases of pediatric AA treated between May 2020 and May 2023 were selected,58 of which received ATR+REMI[research group(RG)]and 50 who received REMI[control group(CG)].Comparative analyses were conducted on the time to loss of eyelash reflex,pain resolution time,recovery time from anesthesia,incidence of adverse events(AEs;respiratory depression,hypoxemia,bradycardia,nausea and vomiting,and hypotension),intraoperative responses(head shaking,limb activity,orientation recovery,safe departure time from the operating room),hemodynamic parameters[oxygen saturation(SPO2),mean arterial pressure,heart rate,and respiratory rate],postoperative sedation score(Ramsay score),and pain level[the Face,Legs,Activity,Cry,Consolability(FLACC)Behavioral Scale].RESULTS Compared with the CG,the RG showed significantly shorter time to loss of eyelash reflex,pain resolution,recovery from anesthesia,and safe departure from the operating room.Furthermore,the incidence rates of overall AEs(head shaking,limb activity,etc.)were lower,and influences on intraoperative hemodynamic parameters and stress response indexes were fewer.The Ramsay score at 30 min after extubation and the FLACC score at 60 min after extubation were significantly lower in the RG than in the CG.CONCLUSION ATR+REMI is superior to REMI alone in children undergoing AA surgery,with a lower incidence of AEs,fewer influences on hemodynamics and stress responses,and better post-anesthesia recovery.

Efficacy and safety of atropine at different concentrations in prevention of myopia progression in Asian children: a systematic review and Meta-analysis of randomized clinical trials

AIM:To assess the efficacy versus the adverse effects of various concentrations of atropine in the prevention of myopia in Asian children.METHODS:Databases(PubMed,EMBASE,the Cochrane Library and Web of science)were comprehensively searched from inception to April 2022.Types of studies included were randomized clinical trials(RCTs).The published languages were limited to English.Two researchers assessed the quality of included studies independently using Cochrane risk of bias tool based on the Cochrane Handbook for Systematic Reviews of Interventions.Funnel plots and Egger’s test were used for detection of publication bias.Meta-analyses were conducted using STATA(version 15.0;StataCorp).RESULTS:A total of 15 RCTs involving 2268 patients were included in the study.In the atropine group,spherical equivalent progressed at a significantly lower rate[weighted mean difference(WMD)=0.39,95%confidence interval(CI):0.23,0.54]than in the control group.A WMD of 0.15 mm was associated with less axial elongation(95%CI-0.19,-0.10).Different doses showed statistically significant differences(P<0.05)and an improved effect could result from a higher concentration.Changes in photopic pupil size and mesopic pupil size in atropine group is 0.70 mm(95%CI:0.33,1.06)and 0.38 mm(95%CI:0.22,0.54)more than the control group.In the present Meta-analysis,no changes in accommodative amplitude(AA)were associated with atropine administration.Atropine administration increased the risk of adverse effects by 1.37 times.CONCLUSION:Concentrations of less than 1%atropine are able to effectively retard diopter and axis growth of myopia in Asian children in a dose-dependent manner.Meanwhile,it caused pupil enlargement,but induced no change in the AA within this range.Further study is required to determine the dosage needed to achieve maximum efficacy and minimal side effects.

Effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization in high myopia mice

AIM:To evaluate effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization(CNV)in high myopia mice.METHODS:The C57BL/6J mice were deprived of the right eye for 4wk,and the high myopia was diagnosed by optometry,the diopter was less than-6.00 D,and CNV was induced by 532 nm laser.The changes of dopamine D1 receptor(DRD1),dopamine D2 receptor(DRD2),and vascular endothelial growth factor A(VEGFA)were detected by Western blot technology at 0.5,1,2h,and 7d after 0.01%,0.05%,and 0.1%atropine eye drops,respectively,the area of CNV was measured.RESULTS:Significant increases were observed on the expression of DRD2 in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).Significant decreases were observed on the expression of DRD1 and VEGFA in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).The area of CNV induced by laser in the drug-treated group was significantly smaller than that in the control group,and the higher the concentration,the more significant the inhibitory effect(P<0.05).CONCLUSION:The 0.01%,0.05%,0.1%atropine eye drops can decrease the level of VEGFA and inhibit high myopia CNV indirectly by up-regulating the level of DRD2 and down-regulating the level of DRD1,and the effect of 0.05%and 0.1%atropine eye drops is more significant.

Atomic-level insight of sulfidation-engineered Aurivillius-related Bi_(2)O_(2)SiO_(3) nanosheets enabling visible light low-concentration CO_(2) conversion

Unraveling atomic-level active sites of layered photocatalyst towards lowconcentration CO_(2) conversion is still challenging.Herein,the yield and selectivity of photocatalytic CO_(2) reduction of the Aurivillius-related oxide semiconductor Bi_(2)O_(2)SiO_(3) nanosheet(BOSO)were largely improved using a surface sulfidation strategy.The experiment and theoretical calculation confirmed that surface sulfidation of the Bi_(2)O_(2)SiO_(3) nanosheet(S-BOSO,6.28 nm)redistributed the charge-enriched Bi sites,extended the solar spectrum absorption to the whole visible range,and considerably enhanced the charge separation,in addition to creating new reaction active sites,as compared to pristine BOSO.Subsequently,surface sulfidation played a switchable role,wherein S-BOSO showed a very high CH_(3)OH generation rate(12.78μmol g^(-1) for 4 h,78.6%selectivity)from low-concentration CO_(2)(1000 ppm)under visible light irradiation,which outperforms most of the state-of-the-art photocatalysts under similar conditions.This study presents an atomic-level modification protocol for engineering reactive sites and charge behaviors to promote solar-to-energy conversion.

Short Term Effect of 0.02%/0.04% Atropine Sulfate Eye Drops on Choroid Thickness in Children with Myopia

Objective: Short-term effects of 0.02%/0.04% atropine sulfate eye drops on choroidal thickness in myopic children using optical coherence tomography angiography. Methods: Thirty-two children aged 6 - 12 years were selected and divided into 22 cases and 44 eyes in the 0.02%/0.04% atropine sulfate eye drops observation group and 10 cases and 20 eyes in the control group. The linear regression equation was used to evaluate the correlation among the spherical equivalent, the axial length and the subfoveal choroidal thickness, moreover, used to evaluate the correlation between the baseline and 6 months later. Independent samples T-test was used to detect whether there was any statistical difference between the nasal 1 mm subfoveal choroidal thickness and the temporal 1 mm subfoveal choroidal, meanwhile, compared with the baseline and 6 months later. P Results: After 6 months follow-up, the axial length increased by 0.067 ± 0.199 mm in the atropine group, 0.201 ± 0.081 mm in the control group (P Conclusions: 1) 0.02%/0.04% atropine sulfate eye drops can delay the growth of axial length and spherical equivalent;2) 0.02%/0.04% atropine sulfate eye drops can thicken the choroid, and the thickness of the nasal side 1mm is the same as that of the temporal side 1 mm;3) At baseline, the subfoveal choroidal thickness has no significant correlation with the axial length and spherical equivalent;4) After 6 months, changes in axial length and spherical equivalent were negatively correlated with changes in subfoveal choroidal thickness.

0.05% atropine on control of myopia progression in Chinese school children: a randomized 3-year clinical trial

·AIM:To evaluate the effect of 0.05%atropine on the control of myopia for 2y(phase I)and on spherical equivalent refraction(SER)progression for 1y(phase II)after its withdrawal in Chinese myopic children.·METHODS:Totally 142 children with myopia were randomly assigned to the 0.05%atropine group or to the placebo group.In phase I,children received 1 treatment for each eye daily.In phase II,the patients received no treatment.Axial length(AL),SER,intraocular pressure(IOP)and atropine-related side effects were assessed at 6 months’intervals.·RESULTS:During phase I,the mean change of SER was-0.46±0.30 D in the atropine group,compared to-1.72±1.12 D in the placebo group(P<0.001).The mean change of AL in the atropine group(0.26±0.30 mm)was significantly shorter than that in the placebo group(0.76±0.62 mm,P=0.002).In addition,in phase II(12mo after the withdrawal of atropine),there was no significant difference in AL change from the atropine group,when compared with that from the placebo group(0.31±0.25 mm vs 0.28±0.26 mm,P>0.05).Furthermore,the change in SER from the atropine group was 0.50±0.41 D,which was significantly lower than 0.72±0.60 D from placebo group,(P<0.05).Finally,there were no statistically significant differences in IOP between the treatment and control groups at any stages(all P>0.05).·CONCLUSION:The use of 0.05%atropine for two consecutive years may effectively control elongation of AL and thus progression of myopia,without significant SER progression 1y after atropine withdrawal.Therefore,treatment with 0.05%atropine daily for 2y is effective and safe.

The diluted atropine for inhibition of myopia progression in Korean children

AIM：To evaluate the efficacy and safety of three different concentrations of diluted atropine for the control of myopia in Korean children,and to assess the risk factors associated with rapid myopia progression.METHODS：A total of 285 children,with refractive errors within the range of-6 diopters（D）between 5 and 14 years of age were included.After using 0.01%,or 0.025%,or 0.05% atropine,for about 1y,changes in refraction,axial lengths and frequency of adverse events were analyzed.Logistic regression analyses were performed to evaluate the risk factors associated with rapid myopia progression.RESULTS：The changes in the mean spherical equivalent values were -0.134 D/mo in the before atropine group,-0.070 D/mo in the 0.01% atropine group,-0.047 D/mo in the 0.025% atropine group,and -0.019 D/mo in the 0.05% atropine group,with significant differences between the groups（P〈0.001）.The axial elongation was 0.046 mm/mo,0.037 mm/mo,0.025 mm/mo,and 0.019 mm/mo respectively,with significant differences between the groups（P=0.003）.The incidence of photophobia and near vision difficulty was not different among the three atropine groups（P=0.425and P=0.356,respectively）.Multivariate logistic regression analyses showed that only highly myopic parents were a significant predictive factor of rapid myopia progression in Korean children（odds ratio,8.155;95% confidence interval,3.626-18.342;P〈0.001）.CONCLUSION：Treatment with 0.01%,0.025% and 0.05% atropine solution inhibits myopia progression in Korean children in a dose-dependent manner.Children with highly myopic parents preferentially shows a rapid myopia progression rate.

Atropine 0.01% eye drops slow myopia progression: a systematic review and Meta-analysis

AIM: To evaluate the effects of atropine 0.01% on slowing myopia progression. METHODS: We searched for relevant studies in the Cochrane Library, PubMed, Embase, Ovid, CBM, CNKI, VIP and Wan Fang Data in Chinese. A supplementary search was conducted in OpenGrey(System for Information on Grey Literature in Europe), the ISRCTN registry, Clinical Trials.gov, and the WHO International Clinical Trials Registry Platform(ICTRP) from the dates of inception to June 30, 2018. RESULTS: Seven randomized controlled trials(RCTs) with a total of 1079 subjects were included(505 in the atropine 0.01% group and 574 in the control group). The results showed that the atropine 0.01% group exhibited significantly greater control of axial growth than the control group (MD=-0.12, 95%CI(-0.19,-0.06))There was also a statistically significant difference between the atropine 0.01% and control groups in the changes in axial length [MD=-0.14, 95%CI(-0.25,-0.03)], but the quality of evidence was low. There were no significant differences between the atropine 0.01% and control groups in the overall effect with respect to diopter value, change in diopter, distance vision and intraocular pressure (MD=0.08, 95%CI(-0.27, 0.42);MD=0.09, 95%CI(-0.17, 0.36);MD=-0.01, 95%CI(-0.02, 0.00);MD=0.08, 95%CI(-0.56,0.40))The sensitivity analysis showed that the conclusion of the Meta-analysis is relatively stable. With respect to adverse events, there were significant differences between the atropine 0.01% and control groups (OR=0.26, 95%CI(0.11, 0.61))CONCLUSION: Based on the available evidence, atropine 0.01% eye drops offer benefits in controlling axial growth and safety without causing significant differences in diopter values, distance vision and intraocular pressure.

Rheology and influence factor of low-concentration Konjac gum solutions

Rheological properties of low-concentration Konjac gum and impacts of concentration,shearing rate,pH value and stirring time on its viscosity were studied.The results show that the viscosity of low-concentration Konjac gum increases with the increase of its concentration.The solution presents pseudo-plasticity fluid,which shows the characters of shear thinning as follows:first,its viscosity decreases gradually as the temperature increases,and then increases with the increase of temperature.The viscosity decreases sharply at both acid and alkaline conditions,indicating that it is influenced apparently by pH value.And the viscosity of low-concentration Konjac gum is also impacted by the stirring time.

VENTRICAL MICROINJECTING ATROPINE OR NALOXONE REDUCES ANALGESIC EFFECTS PRODUCED BY BRAIN STIMULATION IN THE RAT

Stimulating SmI cortex like needling points produced analgesic effect in rats.Under the background of ventrical microinjecting atropine（10μg/2μl）or naloxone（20μg/20μl）tailflick latency（TEL）remained unchanged after stimulating SmI.Comparing atropine group or naloxone group with normal saline group it was shown that there were a statistical difference in TFL between the two groups respectively.Thus,both ACh and endogenous morphine-like factors may participate in analgesic effect as a neurotransmitter of the corticofugal modulation of pain.

Validation of a preclinical dry eye model in New Zealand white rabbits during and following topical instillation of 1% ophthalmic atropine sulfate

Background : The objective of this study was to validate an animal model for dry eye during and after the administration of 1% ophthalmic atropine sulfate(OAS) in New Zealand white(NZW) rabbits.Methods : OAS(1%) was applied three times per day to 30 eyes of 15 healthy NZW rabbits. Sacrifice, enucleation, and lacrimal gland removal took place on days 15, 21,and 30(OAS group). A second group(n = 5) was used as control. Clinical evaluations took place on days 3, 10, 15, 18, 21, 24 and 30. The primary endpoints were:Schirmer I test, tear break-up time(TBUT), and corneal fluorescein staining. As secondary endpoints, clinical changes including intraocular pressure, and histopathology were evaluated.Results : While OAS was administered, the Schirmer I test showed a statistically significant reduction for OAS group versus control( p < 0.001), and versus basal production( p < 0.001). TBUT showed statistically significant differences between groups(days 3 and 10;p = 0.001) and versus basal values(day 3;p < 0.001). Fluorescein staining showed a statistically significant difference(day 3;p = 0.001). The most frequent clinical finding was conjunctival hyperemia(76.9% OAS vs. 20% control). For histopathology, all OAS subjects presented some degree of inflammation(86.7% minimal;13.3% mild) whereas the control presented only 30% minimal inflammation. Goblet cell density showed no difference.Conclusions : The effectiveness of the OAS dry eye model in NZW rabbits as reported in previous studies was confirmed, provided that the application of the drug is maintained throughout the intervention;it is not a viable model after OAS administration is suspended.

Objectively-measured compliance to atropine penalization treatment in children with amblyopia: a pilot study

Background:To date,compliance to atropine penalization in amblyopic children has only been assessed through self-report.The goal of this pilot study is to measure compliance to atropine penalization objectively.Methods:Seven amblyopic children(3-8 years;20/40-20/125 in the amblyopic eye) were enrolled.None had been treated with atropine previously.Children were prescribed either a twice per week or daily atropine regimen by their physicians.Compliance was defined as the percentage of days in which the atropine eye drop was taken compared to the number of doses prescribed.We used medication event monitoring system(MEMS) caps to objectively measure compliance.The MEMS caps are designed to electronically record the time and date when the bottle is opened.The parents of the children were provided a calendar log to subjectively report compliance.Participants were scheduled for return visits at 4 and 12 weeks.Weekly compliance was analyzed.Results:At 4 weeks,objective compliance averaged 88%(range,57-100%),while subjective compliance was 98%(range,90-100%).The actual dose in grams and visual acuity(VA) response relationship(r=0.79,P=0.03) was significantly better than the relationship between regimen and response(r=0.41,P>0.05),or the relationship between actual dose in drops and response(r=0.52,P>0.05).Conclusions:Objective compliance to atropine penalization instructions can be monitored with MEMS,which may facilitate our understanding of the dose-response relationship.Objective compliance with atropine penalization decreases over time and varies with regimen.On average,subjective parental reporting of compliance is overestimated.

Atropine eye-drop-induced acute delirium:a case report

Atropine is an anticholinergic drug which is used in both parental and topical routes.Topical eye-drops of atropine sulfate are used as mydriatic and cycloplegics.Parental atropine-induced delirium is well known but topical atropine eye-drop-induced delirium cases are very limited in literature.In this case report,an elderly man underwent cataract surgery and developed delirium after the use of 1%atropine sulfate eye-drops as prescribed.This case supports the notion that even atropine eye-drops can cause delirium in patients at therapeutic doses in elderly.

Short-term effect of 0.01% atropine sulphate eye gel on myopia progression in children

AIM: To investigate the effect of 0.01% atropine sulphate eye gel on myopia progression and axial elongation in a 6-month treatment in children.METHODS: Totally 185 children aged 6-12 y with binocular myopia of 3.0 D or less in both eyes were enrolled in this prospective cohort study. The atropine group(n=125) received one drop of 0.01% atropine sulphate eye gel in each eye before bedtime daily. The control group included 60 matched children without drug intervention during the same period. The spherical equivalent and axial length was recorded at baseline and the sixth month of treatment. The efficacy was evaluated by the change of the spherical equivalent and axial length. Adverse events were also recorded.RESULTS: The average spherical equivalent and axial length at baseline were not statistically significant between the atropine group(-1.64±0.80 D, 24.13±0.76 mm) and the control group(-1.59±0.94 D, 24.06±0.77 mm, P>0.05). After 6 mo, there was significantly difference in the spherical equivalent progression between the atropine and the control group(-0.27±0.33 vs-0.60±0.35 D, P<0.001),with a relative reduction of 55.0% in myopia progression. The increase in axial elongation in the atropine group was significantly less than control group(0.19±0.14 vs 0.26±0.14 mm, P<0.001), with a relative reduction of 26.9% in axial length. The 84.4% and 38.4% of the eyes progressed by less than 0.50 D and remained stable in the atropine group, compared with 51.7% and 4.2% in the control group. No adverse events were observed.CONCLUSION: Atropine sulphate eye gel 0.01% can slow down myopia progression and axial elongation in children with a 6-month treatment.

Ameliorating Effects of Thyroxine and Atropine in Phosphamidon Intoxicated Chick Embryos

The effects of thyroxine and atropine in ameliorating phosphamidon intoxication in chick embryos was studied. Treatment of phosphamidon significantly enhanced the moriality and abnormalityrates, decreased the average body weights, and cholinesterase activity in chick embryos. When thyroxine was administered to the phosphamidon intoxicated embryos, the above parameters changedsignificantly, indicating an ameliorating effect of thyroxine against phosphamidon intoxication in chick embryos. The combined thyroxine and atropine therapy did not further improve the ameliorating effect. Since in many respects chick embryo development parallels that of mammalian embryos,a short-term use of thyroxine as a protective agent against organophosphate toxicity might be useful

Some worlds about postmortem blood atropine concentrations

Atropine is an anticholinergic drug, used in treatment of spasm and pain. Postmortem blood atropine concentrations tend to be regionally dependent. We reported in this work the analytical findings of atropine in the peripheral and heart blood from a case of suspected death. Atropine was?determined in both peripheral and heart blood by liquid chromatography with tandem mass spectrometry. Towards the reference ranges, the concentration of atropine in the peripheral blood is therapeutic, and in the heart blood is lethal. The high concentration of atropine in the heart blood reflects postmortem redistribution rather than cardiotoxicity. The findings have great implications for forensic toxicology.

Development and Application of a Validated UHPLC Method for the Determination of Atropine and Its Major Impurities in Antidote Treatment Nerve Agent Auto-Injectors (ATNAA) Stored in the Strategic National Stockpiles

The development and implementation of advanced analytical technologies is essential for extending the expiry for complex drug products stored in the Strategic National Stockpiles. Consequently, a novel Ultra High-Performance Liquid Chromatographic (UHPLC) method has been developed for the analysis of atropine and its respective impurities to support the analytical research platform for auto-injectors. This study is part of a larger research effort to improve the efficiency and broaden the applicability of advanced analytical methods for medical counter-measure medications. The current HPLC compendial methodology for atropine sulfate injection requires an analysis time of 40 minutes for atropine. In comparison, the novel gradient UHPLC method required only 8 minutes to evaluate both atropine and its major pharmaceutical impurities. Improved separation was achieved on a Waters Acquity UHPLC BEH C18 1.7 μm, 2.1 × 100 mm column employing gradient elution of mobile phase solvent A (0.1% H3PO4) and solvent B (0.1% H3PO4, 90% ACN, and 10% H2O). The method was validated according to USP Category I requirements for assay. The daily standard calibration curves were linear over a concentration range from 50 μg/mL to 250 μg/mL with a correlation coefficient of >0.999. The detection limit (LOD) and quantitation limit (LOQ) were 3.9 μg/ml and 13.1 μg/ml, respectively. Resolution results indicate that atropine and the following impurities, degradants and a preservative can also be separated and analyzed using this proposed method: noratropine, 4,4’-di-hy-droxydiphenyl ether, 2,4’-dihydroxydiphenyl ether, 4-bromophenol, 4-hydro-xyatropine, tropic acid, apoatropine HCl, atropic acid, hydroquinone, nitroethane, phenol and catechol. The UHPLC method demonstrated enhanced selectivity and significantly reduced the analysis time when compared with the traditional USP compendial HPLC method. The method was successfully applied to the evaluation of atropine in ATNAA auto-injectors lots from the Strategic National Stockpiles.

Neuroprotective effects of low-concentration alpha-tocopherol Confocal laser microscopy observations

BACKGROUND： Alpha-tocopherol （ α-tocopherol） can effectively relieve neuronal damage induced by oxygen-centered free radicals. However, the effective dose remains controversial. OBJECTIVE： To evaluate the protective effects of low-concentration α-tocopherol on neuronal membranes. DESIGN, TIME AND SETTING： Contrast observation and in vitro study, performed at Laboratory of Neurosurgery, Tianjin Huanhu Hospital between April and September 2006. MATERIALS： Fetal cortical neurons were derived from two 14-day pregnant SD rats, and α-tocopherol was provided by Sigma, USA. METHODS： The neurons were randomly assigned to six groups： （1） normal： neurons were cultured under normal conditions; （2） oxidative damage： oxidative free radicals was damaged using the Fenton reaction; （3） α-tocopherol： neurons were cultured in different concentrations of -tocopherol 10, 20, 40, and 80 mg/L for 2 hours, respectively. MAIN OUTCOME MEASURES： Neuronal membrane damage was observed using a confocal laser microscope, and malonaldehyde production was detected using the thiobarbituric acid method. RESULTS： At normal, biological concentrations （10 mg/L）, α-tocopherol induced no change in the damaged neurons （P 〉 0.05）. However, at a concentration of 80 mg/L, the number of damaged neurons was significantly reduced, compared with the damage group （P 〈 0.05）. Malonaldehyde levels following 80 mg/L α-tocopherol treatment were less than the oxygen free radical damage group （P 〈 0.05）, but greater than the control group （P 〈 0.01）. CONCLUSION： A concentration of 80 mg/L α-tocopherol can effectively protect the neuronal cell membrane from oxidative damage