ITPR1: The missing gene in miosis-ataxia syndrome?

The association of early-onset non-progressive ataxia and miosis is an extremely rare phenotypic entity occasionally reported in the literature. To date, only one family (two siblings and their mother) has benefited from a genetic diagnosis by the identification of a missense heterozygous variant (p.Arg36Cys) in the ITPR1 gene. This gene encodes the inositol 1,4,5-trisphosphate receptor type 1, an intracellular channel that mediates calcium release from the endoplasmic reticulum. Deleterious variants in this gene are known to be associated with two types of spinocerebellar ataxia, SCA15 and SCA29, and with Gillespie syndrome that is associated with ataxia, partial iris hypoplasia, and intellectual disability. In this work, we describe a novel individual carrying a heterozygous missense variant (p.Arg36Pro) at the same position in the N-terminal suppressor domain of ITPR1 as the family previously reported, with the same phenotype associating early-onset non-progressive ataxia and miosis. This second report confirms the implication of ITPR1 in the miosis-ataxia syndrome and therefore broadens the clinical spectrum of the gene. Moreover, the high specificity of the phenotype makes it a recognizable syndrome of genetic origin.

Iris stromal cell nuclei deform to more elongated shapes during pharmacologically-induced miosis and mydriasis.

Nuclear shape alteration in ocular tissues, which can be used as a metric for overall cell deformation, may also lead to changes in gene expression and protein synthesis that could affect the biomechanics of the tissue extracellular matrix. The biomechanics of iris tissue is of particular interest in the study of primary angle-closure glaucoma. As the first step towards understanding the mutual role of the biomechanics and deformation of the iris on the activity of its constituent stromal cells, we conducted an ex-vivo study in freshly excised porcine eyes. Iris deformation was achieved by activating the constituent smooth muscles of the iris. Pupillary responses were initiated by inducing miosis and mydriasis, and the irides were placed in a fixative, bisected, and sliced into thin sections in a nasal and temporal horizontal orientation. The tissue sections were stained with DAPI for nucleus, and z-stacks were acquired using confocal microscopy. Images were analyzed to determine the nuclear aspect ratio (NAR) using both three-dimensional (3D) reconstructions of the nuclear surfaces as well as projections of the same 3D reconstruction into flat two-dimensional (2D) shapes. We observed that regardless of the calculation method (i.e., one that employed 3D surface reconstructions versus one that employed 2D projected images) the NAR increased in both the miosis group and the mydriasis group. Three-dimensional quantifications showed that NAR increased from 2.52 ± 0.96 in control group to 2.80 ± 0.81 and 2.74 ± 0.94 in the mydriasis and miosis groups, respectively. Notwithstanding the relative convenience in calculating the NAR using the 2D projected images, the 3D reconstructions were found to generate more physiologically realistic values and, thus, can be used in the development of future computational models to study primary angle-closure glaucoma. Since the iris undergoes large deformations in response to ambient light, this study suggests that the iris stromal cells are subjected to a biomechanically active micro-environment during their in-vivo physiological function.

Expanding the clinical and genetic spectrum of pathogenic variants in STIM1.

INTRODUCTION/AIMS: Stromal interaction molecule 1 (STIM1) is a reticular Ca2+ sensor composed of a luminal and a cytosolic domain. Autosomal dominant mutations in STIM1 cause tubular aggregate myopathy and Stormorken syndrome or its variant York platelet syndrome. In this study we aimed to expand the features related to new variants in STIM1. METHODS: We performed a cross-sectional study of individuals harboring monoallelic STIM1 variants recruited at five tertiary centers involved in a study of inherited myopathies analyzed with a multigene-targeted panel. RESULTS: We identified seven individuals (age range, 26-57 years) harboring variants in STIM1, including five novel changes: three located in the EF-hand domain, one in the sterile α motif (SAM) domain, and one in the cytoplasmatic region of the protein. Functional evaluation of the pathogenic variants using a heterologous expression system and measuring store-operated calcium entry demonstrated their causative role and suggested a link of new variants with the clinical phenotype. Muscle contractures, found in three individuals, showed variability in body distribution and in the number of joints involved. Three patients showed cardiac and respiratory involvement. Short stature, hyposplenism, sensorineural hearing loss, hypothyroidism, and Gilbert syndrome were variably observed among the patients. Laboratory tests revealed hyperCKemia in six patients, thrombocytopenia in two patients, and hypocalcemia in one patient. Muscle biopsy showed the presence of tubular aggregates in three patients, type I fiber atrophy in one patient, and nonspecific myopathic changes in two patients. DISCUSSION: Our clinical, histological, and molecular data expand the genetic and clinical spectrum of STIM1-related diseases.

Functional analyses of STIM1 mutations reveal a common pathomechanism for tubular aggregate myopathy and Stormorken syndrome.

Tubular aggregate myopathy (TAM) is a progressive disorder characterized by muscle weakness, cramps, and myalgia. TAM clinically overlaps with Stormorken syndrome (STRMK), combining TAM with miosis, thrombocytopenia, hyposplenism, ichthyosis, short stature, and dyslexia. TAM and STRMK arise from gain-of-function mutations in STIM1 (stromal interaction molecule 1) or ORAI1, both encoding key regulators of Ca2+ homeostasis, and mutations in either gene result in excessive extracellular Ca2+ entry. The pathomechanistic similarities and differences between TAM and STRMK are only partially understood. Here we provide functional in vitro experiments demonstrating that STIM1 harboring the TAM D84G or the STRMK R304W mutation similarly cluster and exert a dominant effect on the wild-type protein. Both mutants recruit ORAI1 to the clusters, increase cytosolic Ca2+ levels, promote major nuclear import of the Ca2+ -dependent transcription factor NFAT (nuclear factor of activated T cells), and trigger the formation of circular membrane stacks. In conclusion, the analyzed TAM and STRMK mutations have a comparable impact on STIM1 protein function and downstream effects of excessive Ca2+ entry, highlighting that TAM and STRMK involve a common pathomechanism.

Neuropharmacological lesion localization in idiopathic Horner's syndrome in Golden Retrievers and dogs of other breeds.

OBJECTIVE: To investigate whether idiopathic Horner's syndrome (HS) in Golden Retrievers is an exclusively preganglionic disorder based on denervation hypersensitivity pharmacological testing with phenylephrine. ANIMALS STUDIED: Medical records of dogs presented with HS between 2000 and 2012. Dogs presented with additional ocular or systemic signs were excluded. PROCEDURES: Clinical data examined included age, sex, duration of clinical signs, ancillary diagnostic test results, and time to mydriasis on topical ocular application of 1% phenylephrine. Lesions were diagnosed as postganglionic (mydriasis within 20 min) or preganglionic (mydriasis between 20 and 45 min). RESULTS: Medical records of 21 dogs of nine different breeds were included. An etiopathogenesis for Horner's syndrome was determined in five dogs, none of which were Golden Retrievers. All diagnoses correlated with pharmacological lesion localization. Ten Golden Retrievers were included (eight male and two female) with a mean age of 8.5 years (range: 4-13). Lesion localization was diagnosed as postganglionic in eight (mean: 10 min [range: 6-18]) and preganglionic in two Golden Retrievers (20 and 24 min). All cases were unilateral and had completely resolved within 15 weeks (range: 11-20). Recurrence was not reported in any of the patients. CONCLUSIONS: Idiopathic postganglionic HS was diagnosed in eight of 10 Golden Retrievers contradicting previous reports of a purely preganglionic localization. Etiopathogenesis of canine idiopathic HS remains to be determined; nevertheless, a vascular etiology cannot be excluded. Future studies using magnetic resonance angiography may aid in clarifying the pathogenesis.

A dominant STIM1 mutation causes Stormorken syndrome.

Stormorken syndrome is a rare autosomal-dominant disease with mild bleeding tendency, thrombocytopathy, thrombocytopenia, mild anemia, asplenia, tubular aggregate myopathy, miosis, headache, and ichthyosis. A heterozygous missense mutation in STIM1 exon 7 (c.910C>T; p.Arg304Trp) (NM_003156.3) was found to segregate with the disease in six Stormorken syndrome patients in four families. Upon sensing Ca(2+) depletion in the endoplasmic reticulum lumen, STIM1 undergoes a conformational change enabling it to interact with and open ORAI1, a Ca(2+) release-activated Ca(2+) channel located in the plasma membrane. The STIM1 mutation found in Stormorken syndrome patients is located in the coiled-coil 1 domain, which might play a role in keeping STIM1 inactive. In agreement with a possible gain-of-function mutation in STIM1, blood platelets from patients were in a preactivated state with high exposure of aminophospholipids on the outer surface of the plasma membrane. Resting Ca(2+) levels were elevated in platelets from the patients compared with controls, and store-operated Ca(2+) entry was markedly attenuated, further supporting constitutive activity of STIM1 and ORAI1. Thus, our data are compatible with a near-maximal activation of STIM1 in Stormorken syndrome patients. We conclude that the heterozygous mutation c.910C>T causes the complex phenotype that defines this syndrome.

Gain-of-Function Mutation in STIM1 (P.R304W) Is Associated with Stormorken Syndrome.

Stormorken syndrome is a rare autosomal dominant disorder characterized by a phenotype that includes miosis, thrombocytopenia/thrombocytopathy with bleeding time diathesis, intellectual disability, mild hypocalcemia, muscle fatigue, asplenia, and ichthyosis. Using targeted sequencing and whole-exome sequencing, we identified the c.910C > T transition in a STIM1 allele (p.R304W) only in patients and not in their unaffected family members. STIM1 encodes stromal interaction molecule 1 protein (STIM1), which is a finely tuned endoplasmic reticulum Ca(2+) sensor. The effect of the mutation on the structure of STIM1 was investigated by molecular modeling, and its effect on function was explored by calcium imaging experiments. Results obtained from calcium imaging experiments using transfected cells together with fibroblasts from one patient are in agreement with impairment of calcium homeostasis. We show that the STIM1 p.R304W variant may affect the conformation of the inhibitory helix and unlock the inhibitory state of STIM1. The p.R304W mutation causes a gain of function effect associated with an increase in both resting Ca(2+) levels and store-operated calcium entry. Our study provides evidence that Stormorken syndrome may result from a single-gene defect, which is consistent with Mendelian-dominant inheritance.

Pin-point pupils with drowsiness as a presentation of Hashimoto's encephalopathy mimicking pontine infarction.

PURPOSE: Hashimoto's encephalopathy (HE) is an autoimmune-mediated encephalopathy with various manifestations. Pupil size change has never been previously reported as a presentation of HE. CASE REPORT: A 65-year-old woman without previous known thyroid disease presented with acute onset of drowsiness and blurred vision. Neurologically, she was drowsy and had bilateral pinpoint-sized pupils without a light reflex, which probably indicated a bilateral pontine lesion. Brain MRI showed two tiny infarctions at the left midbrain and left thalamus, but did not show a pontine lesion, and demonstrated patent vertebral/basilar arteries. Electroencephalography showed intermittent diffuse slowing. She had an elevated protein level (123 mg/dl) in cerebrospinal fluid without pleocytosis. Of note, she had elevated serum levels of anti-TG antibody (282 IU/mL) and anti-TPO antibody (117 IU/mL). Her symptoms improved spontaneously including gradually normalization of her pupil size in 3 days and clear consciousness in 6 days; therefore, corticosteroid was not administered. CONCLUSION: This case illustrates that physicians should be aware of the treatable condition of HE as a possible diagnosis in patients with bilateral pinpoint pupils and drowsiness but without corresponding MRI lesions.

Evaluation of the effect of tolterodine on pupil diameter and anterior chamber parameters with the Pentacam.

BACKGROUND: To evaluate the effect of tolterodine on pupil diameter and anterior chamber parameters, including volume, depth, and angle, with the Pentacam. METHODS: The 56 eyes of 28 patients who were diagnosed as having overactive bladder and planned to be treated with tolterodine were followed up prospectively in the study. All the patients underwent full ophthalmic examination and scanning with the Pentacam (Oculus, Inc., Wetzlar, Germany) before and 4 weeks after the start date of tolterodine therapy. In addition, the 30 eyes of 15 healthy volunteers were analyzed twice as a control group for repeatability of the measurements. RESULTS: The quantitative descriptors of the anterior chamber before and after the treatment, respectively, were as follows: pupil diameter, 3.02 ± 0.56 mm and 3.01 ± 0.55 mm; anterior chamber depth, 2.74 ± 0.35 mm and 2.75 ± 0.34 mm; anterior chamber volume, 150.23 ± 33.95 mm(3) and 150.27 ± 34.48 mm(3); and anterior chamber angle, 34.56° ± 5.68° and 35.03° ± 5.99°. For all the measurements, the differences did not reach statistical significance (p > .05). Also, the comparison of the same parameters obtained from the first and second measurements of healthy volunteers was not statistically significant (p > .05). CONCLUSION: Our study demonstrates that tolterodine does not affect pupil diameter and anterior chamber parameters, including angle, volume, and depth. Most likely, it is an organ-selective agent, inhibiting muscarinic receptors in the bladder rather than in the anterior segment of the eye.

Efficacy of preoperative nonsteroidal anti-inflammatory drug and the re-dilation technique in minimizing miosis after femtosecond laser in cataract surgery.

PURPOSE: To assess the efficacy of using a nonste-roidal anti-inflammatory drug preoperatively and of applying the re-dilation technique when necessary to minimize pupil size variation when comparing the degree of mydriasis before femtosecond laser pretreatment with that at the beginning of phacoemulsification. METHODS: This retrospective study included patients who underwent cataract surgery using the LenSx (Alcon Laboratories, Inc., Fort Worth, TX). Our routine dilating regimen with flurbiprofen, tropicamide, and phenylephrine was used. The re-dilation technique was applied on eyes that manifested with a pupillary diameter that was smaller than the programmed capsulotomy diameter after laser pretreatment. The technique consists of overcoming pupillary contraction by instilling tropicamide and phenylephrine before phacoemulsification. Pupil size was assessed before femtosecond laser application and at the beginning of phacoemulsification. RESULTS: Seventy-five eyes (70 patients) were included. Nine (12%) eyes underwent the re-dilation technique. There was no significant difference in mean pupillary diameter and mean pupillary area between the two studied surgical time points (p=0.412 and 0.437, respectively). The overall pupillary area constriction was 2.4 mm2. Immediately before opening the wounds for phacoemulsification, none of the eyes presented with a pupillary diameter <5 mm, and 61 (85.3%) eyes had a pupillary diameter >6 mm. CONCLUSION: Preoperative administration of nonsteroidal anti-inflammatory drug and the re-dilation technique resulted in no significant pupil size variation in eyes that were pretreated with the femtosecond laser, when comparing the measurements made before the laser application and at the beginning of phacoemulsification. This approach can avoid the need to proceed with cataract extraction with a constricted pupil.

Ocular surface histopathological insult following sarin and VX exposure and potential treatments in the rat model.

Eye exposure to organophosphate (OP) chemical warfare irreversible acetylcholinesterase inhibitors, results in long-term miosis and impaired visual function. In contrast to the well-documented miotic and ciliary muscle spasm observed following chemical warfare, OP ocular exposure, little is known regarding the ocular surface histopathological insult. The aim of the present study was to determine the degree of the ocular surface insult following sarin or VX ocular exposure and to evaluate potential anti-cholinergic treatments in counteracting this insult. Rats that were whole body exposed to various sarin concentrations (0.049-43 µg/L; 5 min exposure), showed a dose-dependent miotic response and light reflex impairment. Following whole body sarin exposure, a dose dependent ocular surface histopathological insult was developed. A week following exposure to a low concentration of 0.05 µg/L, conjunctival pathology was observed, while corneal insult was noticed only following exposure to a concentration of 0.5 µg/L and above. Both tissues presented poorer outcomes when exposed to higher sarin concentrations. In contrast, eyes topically exposed to 1 µg sarin demonstrated no ocular insult a week following exposure. On the contrary, topical exposure to 1 µg VX resulted in a significant corneal insult. Anticholinergic treatments such as 0.1% atropine or 2% homatropine, given shortly following VX exposure, counteracted this insult. The results of this study show that not only do anti-cholinergic treatments counteract the miotic response, but also prevent the histopathological insult observed when given shortly following OP exposure.

Stormorken Syndrome: A Rare Cause of Myopathy With Tubular Aggregates and Dystrophic Features.

Stormorken syndrome is a rare genetic disorder (MIM 185070) first reported in 1983 with thrombocytopenia, muscle weakness, asplenia, and miosis caused by a mutation of the stromal interaction molecule 1 ( STIM1) gene.1 The muscle weakness is caused by a myopathy with tubular aggregate formation. We report a family in which both child and mother presented with proximal muscle weakness and thrombocytopenia. Histologic, histochemical, and electron microscopy studies were performed on the muscle specimen. It documented accumulation of tubular aggregates and chronic myopathic changes with dystrophic features. Genetic testing revealed that both mother and son carried a missense mutation of c.326A>G in exon 3 of the STIM1 gene, which is novel for Stormorken syndrome. We suggest that patients with unexplained chronic idiopathic thrombocytopenia and proximal weakness have genetic testing for Stormorken syndrome.

[Tubular aggregate myopathy and Stormorken syndrome]. / La myopathie à agrégats tubulaires et le syndrome de Stormorken.

Calcium (Ca2+) is an essential regulator for a large number of cellular functions in various tissues and organs, and small disturbances of Ca2+ homeostasis can severely compromise normal physiology. Intracellular Ca2+ balance is mainly controlled by the reticular Ca2+ sensor STIM1 and the plasma membrane Ca2+ channel ORAI1 through a mechanism known as store-operated Ca2+ entry (SOCE). Gain-of-function mutations in STIM1 or ORAI1 cause excessive extracellular Ca2+ influx, resulting in tubular aggregate myopathy (TAM) and Stormorken syndrome (STRMK). Both disorders are spectra of the same disease and involve muscle weakness, miosis, thrombocytopenia, hyposplenism, ichthyosis, dyslexia, and short stature. Here we summarize the clinical and histological characteristics of both disorders, provide an overview on the genetic causes, and recapitulate the current knowledge on the pathomechanisms leading to the multi-systemic phenotype of tubular aggregate myopathy and Stormorken syndrome.

A dual mechanism promotes switching of the Stormorken STIM1 R304W mutant into the activated state.

STIM1 and Orai1 are key components of the Ca2+-release activated Ca2+ (CRAC) current. Orai1, which represents the subunit forming the CRAC channel complex, is activated by the ER resident Ca2+ sensor STIM1. The genetically inherited Stormorken syndrome disease has been associated with the STIM1 single point R304W mutant. The resulting constitutive activation of Orai1 mainly involves the CRAC-activating domain CAD/SOAR of STIM1, the exposure of which is regulated by the molecular interplay between three cytosolic STIM1 coiled-coil (CC) domains. Here we present a dual mechanism by which STIM1 R304W attains the pathophysiological, constitutive activity eliciting the Stormorken syndrome. The R304W mutation induces a helical elongation within the CC1 domain, which together with an increased CC1 homomerization, destabilize the resting state of STIM1. This culminates, even in the absence of store depletion, in structural extension and CAD/SOAR exposure of STIM1 R304W leading to constitutive CRAC channel activation and Stormorken disease.

Effect of cervical sympathetic ganglionectomy on facial nerve reconstruction using polyglycolic acid-collagen tubes.

A polyglycolic acid-collagen (PGA-c) tube was used as an artificial nerve guide during facial nerve reconstruction performed in a canine model of stellate ganglion block (SGB). The model was generated using a cervical sympathetic ganglionectomy. We evaluated the effects of blood flow on nerve regeneration. First, we resected the left cervical sympathetic ganglion in beagles (n=6). We assessed buccal mucosal blood flow and nasal skin temperatures once per week for 12weeks and Horner's sign 2, 4, and 6months after resection. We compared these values to those measured prior to resection. Blood flow was increased for 6-11weeks, but sympathetic control remained blocked after 6months. Second, we divided beagles into 3 groups: resection models (negative control), from which 7mm of the left facial nerve buccal branch was resected (n=5); reconstruction models, which underwent nerve reconstruction using PGA-c tubes (n=6); and SGB+reconstruction models, which underwent a left cervical sympathetic ganglionectomy immediately after reconstruction (n=6). The right side of the face served as control (n=17). Nerve regeneration was significantly greater in the SGB+reconstruction model dogs than in the reconstruction model dogs, as measured by both electrophysiological and morphological analyses at postoperative week 12. In particular, motor nerve conduction velocity was increased approximately 2-fold (p=0.018). We were able to generate an SGB model with long-term increased blood flow facilitated by the promotion of facial nerve regeneration by PGA-c tubes.

Mice lacking M2 and M3 muscarinic acetylcholine receptors are devoid of cholinergic smooth muscle contractions but still viable.

Cholinergic agents elicit prominent smooth muscle contractions via stimulation of muscarinic receptors that comprise five distinct subtypes (M1-M5). Although such contractions are important for autonomic organs, the role of each subtype has not been characterized precisely because of the poor selectivity of the currently available muscarinic ligands. Here, we generated a mutant mouse line (M2-/-M3-/- mice) lacking M2 and M3 receptors that are implicated in such cholinergic contractions. The relative contributions of M2 and M3 receptors in vitro was approximately 5 and 95% for the detrusor muscle contraction and approximately 25 and 75% for the ileal longitudinal muscle contraction, respectively. Thus, M1, M4, or M5 receptors do not seem to play a role in such contractions. Despite the complete lack of cholinergic contractions in vitro, M2-/-M3-/- mice were viable, fertile, and free of apparent intestinal complications. The urinary bladder was distended only in males, which excludes a major contribution by cholinergic mechanisms to the urination in females. Thus, cholinergic mechanisms are dispensable in gastrointestinal motility and female urination. After 10 Hz electrical field stimulation, noncholinergic inputs were found to be increased in the ileum of M2-/-M3-/- females, which may account for the lack of apparent functional deficits. Interestingly, the M2-/-M3-/- mice had smaller ocular pupils than M3-deficient mice. The results suggest a novel role of M2 in the pupillary dilation, contrary to the well known cholinergic constriction. These results collectively suggest that an additional mechanism operates in the control of pupillary constriction-dilatation.

Miotic tolerance to sarin vapor exposure: role of the sympathetic and parasympathetic nervous systems.

O-isopropyl methylphosphonofluoridate, also known as sarin or GB, is a highly toxic organophosphorous compound that exerts its effect by inhibiting the enzyme acetylcholinesterase. While the effects of a single exposure to GB vapor are well characterized, the effects of multiple exposures to GB vapor are less clear. Previous studies in the rat and guinea pig have demonstrated that multiple exposures result in tolerance to the miotic effect of nerve agents. The aim of the present study was to examine potential mechanisms responsible for tolerance to the miotic effect of GB vapor that has been observed in the rat after multiple exposures. Multiple whole-body inhalation exposures to GB vapor were conducted in a dynamic airflow chamber. Exposures lasted 60 min and each of the three exposures occurred at 24-h intervals. The results of the present study demonstrate that the alpha-adrenergic antagonist phentolamine and the beta-adrenergic receptor antagonist propranolol did not affect the development of tolerance to the miotic effect of GB vapor, suggesting that enhanced sympathetic tone to the eye is not responsible for the observed tolerance. Administration of atropine before the first exposure prevented the tolerance to the miotic effect of GB vapor after the third exposure, suggesting that the tolerance is the result of muscarinic receptor desensitization secondary to receptor stimulation. The present study extends the findings of previous studies to strengthen the hypothesis that the miotic tolerance observed in the rat upon repeated exposure to nerve agents is due to desensitization of muscarinic acetylcholine receptors located on the pupillary sphincter.

Prophylaxis with human serum butyrylcholinesterase protects Göttingen minipigs exposed to a lethal high-dose of sarin vapor.

Serum-derived human butyrylcholinesterase (Hu BChE) is a stoichiometric bioscavenger that is being developed as a potential prophylactic nerve agent countermeasure. Previously, we reported the prophylactic efficacy of Hu BChE in Göttingen minipigs against a whole-body exposure to 4.1mg/m(3) of sarin (GB) vapor, which produced lethality over 60min. Since the toxicity of nerve agent is concentration-dependent, in the present study, we investigated the toxic effects of an almost 3-fold higher rate of GB vapor exposure and the ability of Hu BChE to protect minipigs against this exposure. Male minipigs were subjected to: (1) air exposure; (2) GB vapor exposure; or (3) pretreatment with 7.5mg/kg of Hu BChE by i.m. injection, 24h prior to whole-body exposure to 11.4mg/m(3) of GB vapor for 10min. Electrocardiogram, electroencephalogram, and pupil size were monitored throughout exposure. Blood drawn before and throughout exposure was analyzed for blood gases, electrolytes, metabolites, acetylcholinesterase and BChE activities, and amount of GB bound to red blood cells and plasma. A novel finding was that saline-treated animals exposed to GB vapor did not develop any seizures, but manifested a variety of cardiac and whole blood toxic signs and rapidly died due to respiratory failure. Strikingly, pre-treatment with 7.5mg/kg of Hu BChE not only prevented lethality, but also avoided all cardiac toxic signs manifested in the non-treated cohort. Thus, Hu BChE alone can serve as an effective prophylactic countermeasure versus a lethal high-dose exposure to GB vapor.

Marked miosis caused by deafferenting the oculomotor nuclear complex in the cat.

Animals show highly constricted pupils in certain conditions (e.g., coma). To know the anatomical basis for this miosis, mechanical separation of the oculomotor nuclear complex was done using four transections of the brain. Two frontal transections were placed rostral and caudal to the oculomotor nuclear complex. Two bilateral oblique transections were performed by aiming through the dorsal edge of the Edinger-Westphal nucleus at an angle of 50 degrees from the horizontal plane and vertical to the frontal plane. After the transections, we examined pupillary size for up to 2 weeks to exclude acute effects of deafferentiation. The transections were histologically examined. If the bilateral pupils were highly constricted after the transections, those pupils remained in the miotic state during the survival periods (4-14 days). The deafferented midbrain of the animals, which showed marked miosis, contained the intact oculomotor nuclear complex and nerves with the whole part of the midbrain ventral to them, but with only a small region dorsolateral to them. Given the previous finding that electrical microstimulation of the area ventral to the oculomotor nuclear complex and nerves has failed to elicit pupil constriction, our results suggest that the oculomotor nuclear complex itself could work as a generator for the strong activity of preganglionic pupilloconstrictor neurons.

Efficacy of preoperative nonsteroidal anti-inflammatory drug and the re-dilation technique in minimizing miosis after femtosecond laser in cataract surgery / Eficácia do AINE pré-operatório e da técnica de re-dilatação em minimizar a miose na cirurgia de catarata com laser de femtosegundo

ABSTRACT Purpose: To assess the efficacy of using a nonste­roidal anti-inflammatory drug preoperatively and of applying the re-dilation technique when necessary to minimize pupil size variation when comparing the degree of mydriasis before femtosecond laser pretreatment with that at the beginning of phacoemulsification. Methods: This retrospective study included patients who underwent cataract surgery using the LenSx (Alcon Laboratories, Inc., Fort Worth, TX). Our routine dilating regimen with flurbiprofen, tropicamide, and phenylephrine was used. The re-dilation technique was applied on eyes that manifested with a pupillary diameter that was smaller than the programmed capsulotomy diameter after laser pretreatment. The technique consists of overcoming pupillary contraction by instilling tropicamide and phenylephrine before phacoemulsification. Pupil size was assessed before femtosecond laser application and at the beginning of phacoemulsification. Results: Seventy-five eyes (70 patients) were included. Nine (12%) eyes underwent the re-dilation technique. There was no significant difference in mean pupillary diameter and mean pupillary area between the two studied surgical time points (p=0.412 and 0.437, respectively). The overall pupillary area constriction was 2.4 mm2. Immediately before opening the wounds for phacoemulsification, none of the eyes presented with a pupillary diameter <5 mm, and 61 (85.3%) eyes had a pupillary diameter >6 mm. Conclusion: Preoperative administration of nonsteroidal anti-inflammatory drug and the re-dilation technique resulted in no significant pupil size variation in eyes that were pretreated with the femtosecond laser, when comparing the measurements made before the laser application and at the beginning of phacoemulsification. This approach can avoid the need to proceed with cataract extraction with a constricted pupil.

RESUMO Objetivo: Avaliar a eficácia do uso de anti-inflamatório não-esteróide no pré-operatório e aplicação da técnica de re-dilatação quando necessária para minimizar a variação do tamanho pupilar ao comparar o grau de midríase antes do tra­tamento com laser de femtosegundo no início da facoemulsificação. Métodos: Esse estudo retrospectivo incluiu pacientes que foram submetidos à cirurgia de catarata usando o LenSx (Alcon Laboratories, Inc., Fort Worth, TX). Nosso regime de di­latação de rotina com flurbiprofeno, tropicamida e fenilefrina foi usado. A técnica de re-dilatação doi aplicada em olhos que se manifestaram com um diâmetro pupilar menor do que o diâmetro da capsulotomia programado após o pré-tratamento a laser. A técnica consiste em superar a contração pupilar pela instilação de tropicamida e fenilefrina antes da facoemulsificação. O tamanho pupilar foi avaliado antes da aplicação do laser de femtosegundo e no inicio da facoemulsificação. Resultados: Setenta e cinco olhos (70 pacientes) foram incluídos. Nove (12%) olhos foram submetidos à técnica de re-dilatação. Não houve diferença significativa no diâmetro pupilar médio e na área pupilar média entre os dois tempos cirúrgicos estudados (p=0,412 e 0,437, respectivamente). A constrição global da área pupilar foi de 2,4 mm2. Imediatamente antes de abrir as incisões para a facoemulsificação, nenhum dos olhos apresentava diâmetro pupilar <5 mm e 61 (85,3%) olhos apresentavam um diâmetro pupilar >6 mm. Conclusões: O administração pré-operatória de anti-inflamatório não-esteróide e da técnica de re-dilatação resultaram em uma variação significativa do tamanho pupilar em olhos que foram pré-tratados com laser de femtosegundo, comparando as medidas realizadas antes da aplicação do laser e no inicio da facoemulsificação. Essa abordagem pode evitar a necessidade de prosseguir com a extração da catarata com uma pupila contraída.