Sublingual Atropine Administration for Clozapine-Induced Sialorrhea in Bipolar Disorder: A Case Report Highlighting its Efficacy, Safety Concerns and Challenges.

We discuss a case with off-label sublingual administration of atropine for clozapine-induced sialorrhea (CIS) after failure of two commonly used agents to manage CIS. Atropine had a demonstrable efficacy, as measured by means of sialometry conducted before and after its administration. The salivary rate, initially measured at 0.60 g/min one hour before atropine administration, reduced to 0.23 g/min two hours after administration. Sublingual administration of atropine was found to be an efficacious option for this patient, but safety issues particularly tachycardia and pragmatics such as risk of inadvertent overdose led to its discontinuation after the initial dose. Developing micro-dosing devices for sublingual atropine could enhance administration precision, reduce side effects, and provide a cost-effective solution. The case report also underscores the need to employ sialometry for the objective assessment of treatment outcomes in future research trials for hypersalivation.

Autonomic modulation impacts conduction velocity dynamics and wavefront propagation in the left atrium.

AIMS: Atrial fibrosis and autonomic remodelling are proposed pathophysiological mechanisms in atrial fibrillation (AF). Their impact on conduction velocity (CV) dynamics and wavefront propagation was evaluated. METHODS AND RESULTS: Local activation times (LATs), voltage, and geometry data were obtained from patients undergoing ablation for persistent AF. LATs were obtained at three pacing intervals (PIs) in sinus rhythm (SR). LATs were used to determine CV dynamics and their relationship to local voltage amplitude. The impact of autonomic modulation- pharmacologically and with ganglionated plexi (GP) stimulation, on CV dynamics, wavefront propagation, and pivot points (change in wavefront propagation of ≥90°) was determined in SR. Fifty-four patients were included. Voltage impacted CV dynamics whereby at non-low voltage zones (LVZs) (≥0.5 mV) the CV restitution curves are steeper [0.03 ± 0.03 m/s ΔCV PI 600-400 ms (PI1), 0.54 ± 0.09 m/s ΔCV PI 400-250 ms (PI2)], broader at LVZ (0.2-0.49 mV) (0.17 ± 0.09 m/s ΔCV PI1, 0.25 ± 0.11 m/s ΔCV PI2), and flat at very LVZ (<0.2 mV) (0.03 ± 0.01 m/s ΔCV PI1, 0.04 ± 0.02 m/s ΔCV PI2). Atropine did not change CV dynamics, while isoprenaline and GP stimulation resulted in greater CV slowing with rate. Isoprenaline (2.7 ± 1.1 increase/patient) and GP stimulation (2.8 ± 1.3 increase/patient) promoted CV heterogeneity, i.e. rate-dependent CV (RDCV) slowing sites. Most pivot points co-located to RDCV slowing sites (80.2%). Isoprenaline (1.3 ± 1.1 pivot increase/patient) and GP stimulation (1.5 ± 1.1 increase/patient) also enhanced the number of pivot points identified. CONCLUSION: Atrial CV dynamics is affected by fibrosis burden and influenced by autonomic modulation which enhances CV heterogeneity and distribution of pivot points. This study provides further insight into the impact of autonomic remodelling in AF.

Opposite Contractile Effects of Amphetamine-Related Hallucinogenic Drugs in the Isolated Human Atrium.

The present study examined three hallucinogenic amphetamine derivatives, namely, 2,5-dimethoxy-4-iodoamphetamine (DOI) as well as 2,5-dimethoxy-4-methylamphetamine (DOM) and 4-methylmethcathinone (mephedrone). The objective of this study was to test the hypothesis that DOI, DOM, and mephedrone would increase the contractile force in isolated human atrial preparations in a manner similar to amphetamine. To this end, we measured contractile force under isometric conditions in electrically stimulated (1 Hz) human atrial preparations obtained during open surgery. DOI and DOM alone or in the presence of isoprenaline reduced the contractile force concentration-dependently in human atrial preparations. These negative inotropic effects of DOM and DOI were not attenuated by 10 µM atropine. However, mephedrone increased the contractile force in human atrial preparations in a concentration- and time-dependent manner. Furthermore, these effects were attenuated by the subsequent addition of 10 µM propranolol or pretreatment with 10 µM cocaine in the organ bath. Therefore, it can be concluded that amphetamine derivatives may exert opposing effects on cardiac contractile force. The precise mechanism by which DOI and DOM exert their negative inotropic effects remains unknown at present. The cardiac effects of mephedrone are probably due to the release of cardiac noradrenaline.

Choroidal Changes During and After Discontinuing Long-Term 0.01% Atropine Treatment for Myopia Control.

Purpose: Few studies have explored choroidal changes after cessation of myopia control. This study evaluated the choroidal thickness (ChT) and choroidal vascularity index (CVI) during and after discontinuing long-term low-concentration atropine eye drops use for myopia control. Methods: Children with progressive myopia (6-16 years; n = 153) were randomized to receive 0.01% atropine eye drops or a placebo (2:1 ratio) instilled daily over 2 years, followed by a 1-year washout (no eye drop use). Optical coherence tomography imaging of the choroid was conducted at the baseline, 2-year (end of treatment phase), and 3-year (end of washout phase) visits. The main outcome measure was the subfoveal ChT. Secondary measures include the CVI. Results: During the treatment phase, the subfoveal choroids in both treatment and control groups thickened by 12-14 µm (group difference P = 0.56). During the washout phase, the subfoveal choroids in the placebo group continued to thicken by 6.6 µm (95% confidence interval [CI] = 1.7 to 11.6), but those in the atropine group did not change (estimate = -0.04 µm; 95% CI = -3.2 to 3.1). Participants with good axial eye growth control had greater choroidal thickening than the fast-progressors during the treatment phase regardless of the treatment group (P < 0.001), but choroidal thickening in the atropine group's fast-progressors was not sustained after stopping eye drops. CVI decreased in both groups during the treatment phase, but increased in the placebo group after treatment cessation. Conclusions: On average, compared to placebo, 0.01% atropine eye drop treatment did not cause a differential rate of change in ChT during treatment, but abrupt cessation of long-term 0.01% atropine eye drops may disrupt normal choroidal thickening in children.

0.01% Atropine Eye Drops in Children With Myopia and Intermittent Exotropia: The AMIXT Randomized Clinical Trial.

Importance: Exotropia and myopia are commonly coexistent. However, evidence is limited regarding atropine interventions for myopia control in children with myopia and intermittent exotropia (IXT). Objective: To evaluate the efficacy and safety of 0.01% atropine eye drops on myopia progression, exotropia conditions, and binocular vision in individuals with myopia and IXT. Design, Setting, and Participants: This placebo-controlled, double-masked, randomized clinical trial was conducted from December 2020 to September 2023. Children aged 6 to 12 years with basic-type IXT and myopia of -0.50 to -6.00 diopters (D) after cycloplegic refraction in both eyes were enrolled. Intervention: Participants were randomly assigned in a 2:1 ratio to 0.01% atropine or placebo eye drops administered in both eyes once at night for 12 months. Main Outcomes and Measures: The primary outcome was change in cycloplegic spherical equivalent from baseline at 1 year. Secondary outcomes included change in axial length (AL), accommodative amplitude (AA), exotropia conditions, and binocular vision at 1 year. Results: Among 323 screened participants, 300 children (mean [SD] age, 9.1 [1.6] years; 152 male [50.7%]) were included in this study. A total of 200 children (66.7%) were in the atropine group, and 100 (33.3%) were in the placebo group. At 1 year, the 0.01% atropine group had slower spherical equivalent progression (-0.51 D vs -0.75 D; difference = 0.24 D; 95% CI, 0.11-0.37 D; P < .001) and AL elongation (0.31 mm vs 0.42 mm; difference = -0.11 mm; 95% CI, -0.17 to -0.06 mm; P < .001) than the placebo group. The mean AA change was -3.06 D vs 0.12 D (difference = -3.18 D; 95% CI, -3.92 to -2.44 D; P < .001) in the atropine and placebo groups, respectively. The 0.01% atropine group had a decrease in near magnitude of exodeviation whereas the placebo group had an increase (-1.25 prism diopters [PD] vs 0.74 PD; difference = -1.99 PD; 95% CI, -3.79 to -0.19 PD; P = .03). In the atropine vs placebo group, respectively, the incidence of study drug-related photophobia was 6.0% (12 of 200 participants) vs 8.0% (8 of 100 participants; difference = -2.0%; 95% CI, -9.4% to 3.7%; P = .51) and for blurred near vision was 6.0% (12 of 200 participants) vs 7.0% (7 of 100 participants) (difference = -1.0%; 95% CI, -8.2% to 4.5%; P = .74). Conclusions and Relevance: The findings of this randomized clinical trial support use of 0.01% atropine eye drops, although compromising AA to some extent, for slowing myopia progression without interfering with exotropia conditions or binocular vision in children with myopia and IXT. Trial Registration: Chinese Clinical Trial Registry Identifier: ChiCTR2000039827.

Voltage dependence of M2 muscarinic receptor antagonists and allosteric modulators.

Muscarinic receptors are G protein-coupled receptors (GPCRs) that play a role in various physiological functions. Previous studies have shown that these receptors, along with other GPCRs, are voltage-sensitive; both their affinity toward agonists and their activation are regulated by membrane potential. To our knowledge, whether the effect of antagonists on these receptors is voltage-dependent has not yet been studied. In this study, we used Xenopus oocytes expressing the M2 muscarinic receptor (M2R) to investigate this question. Our results indicate that the potencies of two M2R antagonists, atropine and scopolamine, are voltage-dependent; they are more effective at resting potential than under depolarization. In contrast, the M2R antagonist AF-DX 386 did not exhibit voltage-dependent potency.Furthermore, we discovered that the voltage dependence of M2R activation by acetylcholine remains unchanged in the presence of two allosteric modulators, the negative modulator gallamine and the positive modulator LY2119620. These findings enhance our understanding of GPCRs' voltage dependence and may have pharmacological implications.

Myopia Control in Caucasian Children with 0.01% Atropine Eye Drops: 1-Year Follow-Up Study.

Background and Objectives: Myopia is the most widespread ocular disorder globally and its prevalence has been increasing over the past decades. Atropine eye drops stand out as the only pharmacological intervention used in clinical practice to control myopia progression. The aim of this study was to explore the effect of 0.01% atropine eye drops on myopia progression. Patients and Methods: Healthy children aged 6-12 years with cycloplegic spherical equivalent (SE) from -0.5 D to -5.0 D and astigmatism ≤1.5 D were included. Myopia progression was assessed by changes in SE and axial length (AL) over 1 year and SE changes 1 year before the study enrollment and during the 1-year follow-up. Adverse events were evaluated based on complaints reported by either parents or the children themselves during follow-up visits. Results: The analysis involved 55 patients in the 0.01% atropine eye drops group and 66 in the control group. After the 1-year follow-up, the change in SE was -0.50 (-2.25-0.50) D in the control group compared to -0.50 (-1.50-0.50) D in the 0.01% atropine group (p = 0.935); AL change was 0.31 (0.18) mm in the control group and 0.29 (0.18) mm in the 0.01% atropine group (p = 0.480). The change in SE was -0.68 (-2.0--0.25) D/year before the study and remained similar -0.50 (-2.25-0.25) D over the 1-year follow-up in the control group (p = 0.111); SE change was reduced from -1.01 (-2.0--0.25) D/year before the study to -0.50 (-1.5-0.5) D over the 1-year follow-up in the 0.01% atropine group (p < 0.001). In the 0.01% atropine group, ten (16.4%) children experienced mild adverse events, including blurred near vision, ocular discomfort, photophobia, dry eyes, and anisocoria. Conclusions: Compared to the control group, the administration of 0.01% atropine eye drops demonstrated no significant effect on changes in SE and AL over a 1-year follow-up. However, children in the 0.01% atropine group initially experienced higher myopia progression, which decreased with treatment over the course of 1 year. Future studies should explore the long-term effects, rebound effects, potential genetic associations, and efficacy of higher doses of atropine in managing myopia progression.

Absorption and attachment of atropine to etafilcon A contact lenses.

PURPOSE: Myopia (short-sightedness) is a growing vision problem worldwide. Currently atropine eye drops are used to control the progression of myopia but these suffer from potential lack of bioavailability and low ocular residence time. Commercially available myopia control contact lenses are also used to limit myopia progression, but neither atropine nor contact lenses individually completely stop progression. Development of myopia control contact lenses which could deliver therapeutic doses of atropine is thus desirable and may provide increased efficacy. This study was designed to explore the feasibility of attaching atropine to etafilcon A contact lenses through an esterification reaction. METHODS: Carboxylic acid groups on etafilcon A contact lenses were quantified using Toluidine Blue O. The carboxylic acid groups in etafilcon A contact lenses were activated using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC-HCl) and N-hydroxysuccinimide (NHS) crosslinkers after which atropine was added to undergo potential binding via esterification. Atropine was released from lenses by alkaline hydrolysis. Reverse phase high performance liquid chromatography (HPLC) was used to detect and quantify the released atropine and its degradation products in solution. Contact lenses that had not been activated by EDC-NHS (controls) were also examined to determine the amount of atropine that could be absorbed rather than chemically bound to lenses. RESULTS: Each etafilcon A contact lens contained 741.1 ± 5.5 µg carboxylic acid groups which may be available for esterification. HPLC had a limit of detection for atropine of 0.38 µg/mL and for tropic acid, an atropine degradation product, of 0.80 µg/mL. The limits of quantification were 1.16 µg/mL for atropine and 2.41 µg/mL for tropic acid in NH4HCO3. The etafilcon A lenses adsorbed up to 7.69 µg atropine when incubated in a 5 mg/mL atropine solution for 24 h. However, there was no evidence that atropine could be chemically linked to the lenses, as washing in a high concentration of NaCl removed all the atropine from the contact lenses with no atropine being subsequently released from the lenses after incubating in 0.01 N NH4HCO3. CONCLUSIONS: Etafilcon A contact lenses contain free carboxylic acids which may be an appropriate option for attaching drugs such as atropine. Etafilcon A lenses adsorbed up to 7.69 µg atropine, which would be more than enough to deliver atropine to eyes to control myopia. However, atropine could not be chemically bound to the carboxylic acids of the etafilcon A lenses using this methodology.

Impact of salivary flow inhibition on masticatory behaviours in healthy individuals.

BACKGROUND: It remains unclear how the salivary flow and the fat content of food affect bolus formation during mastication. OBJECTIVES: We aimed to clarify: (1) how hyposalivation affects jaw-closing and hyoid-elevating muscle activities in bolus formation, and (2) if the effect of hyposalivation on muscle activity depends on the fat content of food. METHODS: Eighteen healthy male volunteers were instructed to freely ingest four test foods: Plain, Fat without seasoning, Fat with seasoning, and Soft rice crackers. Masseter and suprahyoid electromyographic activities were recorded before and 30 min after the administration of atropine sulfate, a muscarinic receptor antagonist that induces hyposalivation. RESULTS: Hyposalivation extended the masticatory duration significantly in all the test foods except Fat with seasoning. Masticatory cycle time was significantly longer with vs without hyposalivation for the Soft (p = .011). Suprahyoid activity/cycle was significantly greater with vs without hyposalivation (p = .013). Masticatory cycle time was significantly longer at the late stage with vs without hyposalivation for the Soft (p < .001). Suprahyoid activity/cycle was significantly greater at the middle (p = .045) and late stages (p = .002) with vs without hyposalivation for the Soft and greater at the late stage with vs without hyposalivation for the Plain (p = .043). Changes in masticatory cycle time and suprahyoid activity/cycle for these foods had significantly positive relationship (p < .001). CONCLUSION: Hyposalivation-induced changes in masticatory behaviours resulted from the middle and late stage suprahyoid activity. Fat content and seasoning compensate for salivary flow inhibition.

Effect of pH and temperature on tropane alkaloids within a processing strategy to provide safe infant cereal-based food.

Tropane alkaloids (TAs) are secondary metabolites from weeds that can contaminate cereals and vegetables during harvest. Due to their toxicity, the Regulation (EC) 2023/915 sets maximum levels for atropine and scopolamine in cereal-based foods for infants containing millet, sorghum, buckwheat or their derived products. The aim of this study was to evaluate the effect of pH and temperature on the stability of TAs, as possible parameters in thermal processing to mitigate this chemical hazard in cereal-based infant food. The effect of pH (4 and 7) and temperature (80 °C and 100 °C) was assessed in buffer solutions. Also, treatment at 180 °C was performed in spiked and naturally incurred millet flour to assess the effect of high temperature, simulating cooking or drying, on the stability of TAs in the cereal matrix. The fate of 24 TAs was assessed by UHPLC-MS/MS. TAs showed high thermostability, although it was variable depending on the specific compound, pH, temperature and treatment time. In buffer solutions, higher degradation was found at 100 °C and pH 7. In spiked millet flour at 180 °C for 10 min, scopolamine and atropine contents decreased by 25 % and 22 %, similarly to other TAs which also showed a slow thermal degradation. Atropine, scopolamine, anisodamine, norscopolamine, scopine and scopoline were found in naturally contaminated millet flour. Interestingly, naturally incurred atropine was more thermostable than when spiked, showing a protective effect of the cereal matrix on TAs degradation. The present results highlight the need for an accurate monitorization of TAs in raw materials, as this chemical hazard may remain in infant cereal-based food even after intense thermal processing.

Comparison of Changes in Retinal Vascular Density and Thickness After Using Low-Level Red Light and 0.01% Atropine in Premyopic Children.

Purpose: To compare changes in superficial retinal vascular density (SRVD), deep retinal vascular density (DRVD), and retinal thickness (RT) of the macular zone after repeated low-level red light (RLRL) and 0.01% atropine exposure in premyopic schoolchildren. Methods: Prospective randomized trial. Sixty-nine schoolchildren with cycloplegic refraction >-0.75 D and ≤0.50 D were randomly assigned to RLRL and 0.01% atropine groups. SRVD, DRVD, and RT were measured using swept-source optical coherence tomography at baseline and six months. The macular zone was divided into three concentric rings (fovea, parafovea, and perifovea) using the Early Treatment Diabetic Retinopathy Study. Results: After six months, the whole, parafoveal, and perifoveal SRVD significantly increased in the two groups (all P < 0.05). Multivariate regression analyses showed that none of these changes varied significantly between the two groups (all P > 0.05), whereas foveal SRVD remained stable in both groups (all P > 0.05). In the RLRL group, the whole and perifoveal DRVD increased significantly (all P < 0.05), whereas no statistical difference was observed in the foveal and parafoveal DRVD. DRVD remained stable in the 0.01% atropine group (all P > 0.05). No significant differences were observed in RT changes between the two groups (all P > 0.05). In comparison, there were no significant changes in SRVD, DRVD, or RT after six months in the placebo group in our previous study. Conclusions: SRVD increased similarly in the RLRL and 0.01% atropine groups, whereas DRVD increased only in the former group. There were no significant RT changes in either group after six months of treatment in premyopic schoolchildren. Translational Relevance: This research observed the effects of low-level red light and 0.01% atropine on retinal vasculature, offering valuable insights into myopia progression prevention.

Characterization of Humanized Mouse Model of Organophosphate Poisoning and Detection of Countermeasures via MALDI-MSI.

Organophosphoate (OP) chemicals are known to inhibit the enzyme acetylcholinesterase (AChE). Studying OP poisoning is difficult because common small animal research models have serum carboxylesterase, which contributes to animals' resistance to OP poisoning. Historically, guinea pigs have been used for this research; however, a novel genetically modified mouse strain (KIKO) was developed with nonfunctional serum carboxylase (Es1 KO) and an altered acetylcholinesterase (AChE) gene, which expresses the amino acid sequence of the human form of the same protein (AChE KI). KIKO mice were injected with 1xLD50 of an OP nerve agent or vehicle control with or without atropine. After one to three minutes, animals were injected with 35 mg/kg of the currently fielded Reactivator countermeasure for OP poisoning. Postmortem brains were imaged on a Bruker RapifleX ToF/ToF instrument. Data confirmed the presence of increased acetylcholine in OP-exposed animals, regardless of treatment or atropine status. More interestingly, we detected a small amount of Reactivator within the brain of both exposed and unexposed animals; it is currently debated if reactivators can cross the blood-brain barrier. Further, we were able to simultaneously image acetylcholine, the primary affected neurotransmitter, as well as determine the location of both Reactivator and acetylcholine in the brain. This study, which utilized sensitive MALDI-MSI methods, characterized KIKO mice as a functional model for OP countermeasure development.

N-acetylcysteine as a potentially safe adjuvant in the treatment of neurotoxicity due to pirimiphos-methyl poisoning.

Exogenous, well-established antioxidant N-acetylcysteine can reduce or prevent the deleterious effects of pesticides. In this study, utilizing a mouse model of daily single dose of N-acetylcysteine administration, we investigated the impact of this adjuvant on the treatment with atropine and/or obidoxime as well as oxidative stress response in pyrimiphos-methyl-induced toxicity. We found that N-acetylcysteine significantly reduces the oxidative stress generated by pyrimiphos-methyl. The therapy consisting of atropine and/or obidoxime routinely used in organophosphorous insecticide poisonings, including pyrimiphos-methyl, had no effect on the antioxidant properties of N-acetylcysteine. Adjunctive treatment offered by N-acetylcysteine fills therapeutic gap and may provide the full potential against pyrimiphos-methyl-induced toxicity.

Enhanced ophthalmic bioavailability and stability of atropine sulfate via sustained release particles using polystyrene sulfonate resin.

Atropine sulfate (ATS) eye drops at low concentrations constitute a limited selection for myopia treatment, with challenges such as low ophthalmic bioavailability and inadequate stability. This study proposes a novel strategy by synthesizing ophthalmic sodium polystyrene sulfonate resin (SPSR) characterized by a spherical shape and uniform size for cationic exchange with ATS. The formulation of ATS@SPSR suspension eye drops incorporates xanthan gum and hydroxypropyl methylcellulose (HPMC) as suspending agents. In vitro studies demonstrated that ATS@SPSR suspension eye drops exhibited sustained release characteristics, and tropic acid, its degradation product, remained undetected for 30 days at 40 °C. The ATS levels in the tear fluids and aqueous humor of New Zealand rabbits indicated a significant increase in mean residence time (MRT) and area under the drug concentration-time curve (AUC0-12h) for ATS@SPSR suspension eye drops compared to conventional ATS eye drops. Moreover, safety assessment confirmed the non-irritating nature of ATS@SPSR suspension eye drops in rabbit eyes. In conclusion, the cation-responsive sustained-release ATS@SPSR suspension eye drops enhanced the bioavailability and stability of ATS, offering a promising avenue for myopia treatment.

Efficacy and safety of 0.01% atropine combined with orthokeratology lens in delaying juvenile myopia: An observational study.

It aims to study the efficacy and safety of low-concentration Atropine combined with orthokeratology (OK) lens in delaying juvenile myopia. This is a prospective study, 172 adolescents aged 8 to 12 years who were admitted to the diopter department of Hengshui People Hospital from April 2021 to May 2022 were selected. According to the equivalent spherical diopter measured at the time of initial diagnosis, myopic patients were randomly divided into low myopia group (group A) and moderate myopia group (group B). At the same time, according to the different treatment methods, the patients were divided into the group wearing frame glasses alone (group c), the group wearing frame glasses with low-concentration Atropine (group d), the group wearing corneal shaping glasses alone at night (group e), and the group wearing corneal shaping glasses at night with low-concentration Atropine (group f). The control effect of myopia development and axial elongation in group f was better than that in groups d and e (P < .05). The effect of controlling myopia development and axial elongation in group f is with P > .05. The probability of postoperative adverse reactions in group f was lower and lower than that in the other groups. Low-concentration atropine combined with OK lens could effectively delay the development of juvenile myopia, and had a high safety. Low-concentration of Atropine would not have a significant impact on the basic tear secretion and tear film stability. Nightwear of OK lens also had no significant impact, but it would significantly reduce the tear film rupture time in the first 3 months, and at the same time, the tear film rupture time would be the same after 6 months as before treatment.

Combination effect of optical defocus and low dose atropine in myopia control: Study protocol for a randomized clinical trial.

BACKGROUND: Myopia, characterized by excessive axial elongation of the eyeball, increases risks of having sight-threatening diseases and impose a financial burden to healthcare system. Although myopic control interventions showed their effectiveness in slowing progression, the efficacy varies between individuals and does not completely halt progression. The study aims to investigate the efficacy of combining 0.01% atropine administered twice daily with optical defocus for myopia control in schoolchildren. METHODS AND DESIGN: This is a prospective, parallel-group, single-blinded, randomized, active-control trial (ClinicalTrials.gov identifier: NCT06358755). Myopic schoolchildren with no previous myopic control interventions aged between 7 to 12 years will be recruited. They will be randomly allocated into two groups (n = 56 per group) after baseline measurement. Both groups will receive 0.01% atropine twice per day for 18 months (one drop in the morning and the other drop at night before bedtime). Defocus incorporated multiple segments (DIMS) spectacle lenses will be prescribed in atropine plus optical defocus (ATD) treatment group while single vision spectacle lenses will be given in atropine only (AT) group. Cycloplegic refraction and axial lengths will be monitored every 6 months over 18-month study period. The primary outcomes are changes in cycloplegic refraction and axial lengths relative to the baseline over the study period. DISCUSSION: The result will examine the combination effect of low dose atropine and myopic defocus on myopia control in a randomized controlled study. The findings will also explore the potential benefits of applying 0.01% atropine twice per day on myopic control and its potential side effects.

Prolonged hypotony maculopathy following uneventful strabismus surgery.

Hypotony is a rare postoperative complication of strabismus surgery. Resolution has been reported to occur within 1 month of surgery. Here, we describe the case of a 14-year-old boy with prolonged hypotony maculopathy following uneventful bilateral medial rectus recession. The hypotony resolved without long-term sequela after 7 months of treatment with topical steroids and atropine. Ultrasound biomicroscopy revealed a ciliary body effusion, which we hypothesize was the cause of decreased aqueous humor production and hypotony.

[ADDITION OF LOW-CONCENTRATION ATROPINE IN COMBINATION OF DUAL-FOCUS CONTACT LENSES FOR MYOPIA CONTROL TREATMENT].

INTRODUCTION: The importance of myopia management lies in the desire to minimize the potential ocular risks that increase with high myopia. AIMS: To assess the decrease in myopia progression using topical low dose atropine combined with peripheral blur contact lenses (CL). METHODS: This retrospective review study included 25 children between the ages of 8.5 years to 14 years. The children all had a minimal increase in myopia of 0.75D during the year prior to treatment. The children were divided into two groups. The control group included 14 children who wore single-vision spectacles )SV) averaging 3.20±0.9D ranging from 1.5-5.3D. The study group included 11 children who wore dual-focus CL, with an average prescription of 3.4±0.7D ranging from 2.5 to 4.3D, for one year. At that point, when an additional myopia increase was observed, the children were additionally treated with topical 0.01% atropine for two years (CL+A0.01). RESULTS: There was an increase in myopia in the SV group of 1.12±0.52D, 1.08±0.56D and 0.96±0.53D in the first, second, and third years, respectively. The myopia increase in the CL+A0.01 group was 0.57±0.48D, 0.14±0.34D, and 0.17±0.29D in the first, second, and third years, respectively. CONCLUSIONS: Low-dose atropine combined with peripheral blur contact lenses was effective in decreasing myopia progression in this study. Additional, larger-scale studies are required in the future. DISCUSSION: This study found a significant decrease in myopia progression in the second and third years of treatment. The CL group showed less effectivity than the CL+A0.01 group.

Human Plasma Butyrylcholinesterase Hydrolyzes Atropine: Kinetic and Molecular Modeling Studies.

The participation of butyrylcholinesterase (BChE) in the degradation of atropine has been recurrently addressed for more than 70 years. However, no conclusive answer has been provided for the human enzyme so far. In the present work, a steady-state kinetic analysis performed by spectrophotometry showed that highly purified human plasma BChE tetramer slowly hydrolyzes atropine at pH 7.0 and 25 °C. The affinity of atropine for the enzyme is weak, and the observed kinetic rates versus the atropine concentration was of the first order: the maximum atropine concentration in essays was much less than Km. Thus, the bimolecular rate constant was found to be kcat/Km = 7.7 × 104 M-1 min-1. Rough estimates of catalytic parameters provided slow kcat < 40 min-1 and high Km = 0.3-3.3 mM. Then, using a specific organophosphoryl agent, echothiophate, the time-dependent irreversible inhibition profiles of BChE for hydrolysis of atropine and the standard substrate butyrylthiocholine (BTC) were investigated. This established that both substrates are hydrolyzed at the same site, i.e., S198, as for all substrates of this enzyme. Lastly, molecular docking provided evidence that both atropine isomers bind to the active center of BChE. However, free energy perturbations yielded by the Bennett Acceptance Ratio method suggest that the L-atropine isomer is the most reactive enantiomer. In conclusion, the results provided evidence that plasma BChE slowly hydrolyzes atropine but should have no significant role in its metabolism under current conditions of medical use and even under administration of the highest possible doses of this antimuscarinic drug.

Seizure suppression and neuroprotection in soman-exposed rats following delayed intramuscular treatment of adenosine A1 receptor agonist as an adjunct to standard medical treatment.

Soman produces excitotoxic effects by inhibiting acetylcholinesterase in the cholinergic synapses and neuromuscular junctions, resulting in soman-induced sustained status epilepticus (SSE). Our previous work showed delayed intramuscular (i.m.) treatment with A1 adenosine receptor agonist N-bicyclo-[2.2.1]-hept-2-yl-5'-chloro-5'-deoxyadenosine (ENBA) alone suppressed soman-induced SSE and prevented neuropathology. Using this same rat soman seizure model, we tested if delayed therapy with ENBA (60 mg/kg, i.m.) would terminate seizure, protect neuropathology, and aid in survival when given in conjunction with current standard medical countermeasures (MCMs): atropine sulfate, 2-PAM, and midazolam (MDZ). Either 15- or 30-min following soman-induced SSE onset, male rats received atropine and 2-PAM plus either MDZ or MDZ + ENBA. Electroencephalographic (EEG) activity, physiologic parameters, and motor function were recorded. Either 2- or 14-days following exposure surviving rats were euthanized and perfused for histology. All animals treated with MDZ + ENBA at both time points had 100% EEG seizure termination and reduced total neuropathology compared to animals treated with MDZ (2-day, p = 0.015 for 15-min, p = 0.002 for 30-min; 14-day, p < 0.001 for 15-min, p = 0.006 for 30-min), showing ENBA enhanced MDZ's anticonvulsant and neuroprotectant efficacy. However, combined MDZ + ENBA treatment, when compared to MDZ treatment groups, had a reduction in the 14-day survival rate regardless of treatment time, indicating possible enhancement of MDZ's neuronal inhibitory effects by ENBA. Based on our findings, ENBA shows promise as an anticonvulsant and neuroprotectant in a combined treatment regimen following soman exposure; when given as an adjunct to standard MCMs, the dose of ENBA needs to be adjusted.