Influence of miosis and laser peripheral iridotomy on intraocular lens power calculation in patients with primary angle closure disease.

OBJECTIVES: To evaluate the effect of miosis and laser peripheral iridotomy (LPI) on intraocular lens (IOL) power prediction and ocular biometry in eyes with primary angle closure disease (PACD). METHODS: In this prospective observational study, primary angle closure suspects (PACS), and subjects classified with primary angle closure (PAC)/primary angle-closure glaucoma (PACG) undergoing LPI were enrolled. Ocular biometric parameters were measured with IOLMaster700 at baseline (T0), one week after pilocarpine instillation (T1), and another week post LPI (T2). Biometric changes and the IOL power predicted for emmetropia using Barrett Universal II, Haigis, Holladay2, Hoffer Q and SRK/T formulae were analysed and compared among different time points. RESULTS: 100 eyes of 50 PACS and 50 PAC/PACG patients were enrolled. Following pilocarpine-induced miosis, lens thickness (LT) increased and anterior chamber depth (ACD) decreased (all groups p < 0.01), while white-to-white diameter decreased and central corneal thickness increased significantly only in the PACS cohort (both p < 0.01). Compared to baseline, LPI induced an increase of ACD and a slight decrease of LT in PACS (both p < 0.01), whereas only axial length changed significantly (p = 0.012) in the PAC/PACG cohort. Regardless of the formula used, no significant difference to the predicted IOL power for emmetropia existed among the three time points in each group (all p > 0.1). CONCLUSION: We report the changes of anterior segment parameters induced by miosis and LPI in PACD. These interventions do not significantly affect the IOL power calculation predicted for emmetropia in Chinese eyes when common third-, fourth-and new generation IOL formulae are used.

Evaluating the effects of betaine on testicular ischemia/reperfusion injury induced by torsion/detorsion in the rat.

In this research, the effects of betaine on testicular ischemia-reperfusion were evaluated. Forty rats were randomly divided into 4 groups of sham, torsion/detorsion (TD), torsion/detorsion with two different dosage of betaine 200 mg/kg, and 300 mg/kg, respectively. At the end of the experiment, the testosterone concentration, sperm motility, concentration and vitality, oxidative stress biomarkers including Malondialdehyde (MDA), Glutathione peroxidase (GPx), Catalase (CAT), and total antioxidant capacity (TAC) were assessed. Moreover, histopathological parameters including seminiferous tubules diameter (STD), seminiferous epithelium thickness (SET), spermatogonia nuclei diameter (SpND), Sertoli cell nuclei diameter (StND) and miotic index were evaluated. The testosterone concentration altered during torsion/detorsion and betaine could increase slightly the testosterone concentration after 15 days. Sperm motility and vitality significantly increased in the betaine treated groups compared to the TD group on days 3 and 15. Among oxidative stress biomarkers, only CAT on day 3 and GPx on day 15 were significantly higher in the betaine groups compared to the TD group. Among histopathological parameters an increase in the STD and SET in betaine-200 and betaine-300 groups were observed on 15th day of post-surgery, compared to the TD group. These findings indicate that betaine can ameliorate testicular damages triggered by torsion/detorsion.

Acute Inhibitory Effects of Antidepressants on Lacrimal Gland Secretion in the Anesthetized Rat.

Purpose: Patients that medicate with antidepressants commonly report dryness of eyes. The cause is often attributed to the anticholinergic properties of the drugs. However, regulation of tear production includes a substantial reflex-evoked component and is regulated via distinct centers in the brain. Further, the anticholinergic component varies greatly among antidepressants with different mechanisms of action. In the current study it was wondered if acute administration of antidepressants can disturb production of tears by affecting the afferent and/or central pathway. Methods: Tear production was examined in vivo in anesthetized rats in the presence or absence of the tricyclic antidepressant (TCA) clomipramine or the selective serotonin reuptake inhibitor (SSRI) escitalopram. The reflex-evoked production of tears was measured by challenging the surface of the eye with menthol (0.1 mM) and cholinergic regulation was examined by intravenous injection with the nonselective muscarinic agonist methacholine (1-5 µg/kg). Results: Acute administration of clomipramine significantly attenuated both reflex-evoked and methacholine-induced tear production. However, escitalopram only attenuated reflex-evoked tear production, while methacholine-induced production of tears remained unaffected. Conclusions: This study shows that antidepressants with different mechanisms of action can impair tear production by attenuating reflex-evoked signaling. Further, antimuscarinic actions are verified as a likely cause of lacrimal gland hyposecretion in regard to clomipramine but not escitalopram. Future studies on antidepressants with different selectivity profiles and mechanisms of action are required to further elucidate the mechanisms by which antidepressants affect tear production.

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.

Role of TRPP2 in mouse airway smooth muscle tension and respiration.

The transient receptor potential polycystin-2 (TRPP2) is encoded by the Pkd2 gene, and mutation of this gene can cause autosomal dominant polycystic kidney disease (ADPKD). Some patients with ADPKD experience extrarenal manifestations, including radiologic and clinical bronchiectasis. We hypothesized that TRPP2 may regulate airway smooth muscle (ASM) tension. Thus, we used smooth muscle-Pkd2 conditional knockout (Pkd2SM-CKO) mice to investigate whether TRPP2 regulated ASM tension and whether TRPP2 deficiency contributed to bronchiectasis associated with ADPKD. Compared with wild-type mice, Pkd2SM-CKO mice breathed more shallowly and faster, and their cross-sectional area ratio of bronchi to accompanying pulmonary arteries was higher, suggesting that TRPP2 may regulate ASM tension and contribute to the occurrence of bronchiectasis in ADPKD. In a bioassay examining isolated tracheal ring tension, no significant difference was found for high-potassium-induced depolarization of the ASM between the two groups, indicating that TRPP2 does not regulate depolarization-induced ASM contraction. By contrast, carbachol-induced contraction of the ASM derived from Pkd2SM-CKO mice was significantly reduced compared with that in wild-type mice. In addition, relaxation of the carbachol-precontracted ASM by isoprenaline, a ß-adrenergic receptor agonist that acts through the cAMP/adenylyl cyclase pathway, was also significantly attenuated in Pkd2SM-CKO mice compared with that in wild-type mice. Thus, TRPP2 deficiency suppressed both contraction and relaxation of the ASM. These results provide a potential target for regulating ASM tension and for developing therapeutic alternatives for some ADPKD complications of the respiratory system or for independent respiratory disease, especially bronchiectasis.

The effect of co-administration of pentylenetetrazole with pilocarpine: New modified PTZ models of kindling and seizure.

BACKGROUND: Drug resistance is a major problem in the treatment of epilepsy. There is a critical need for new epilepsy models to evaluate antiepileptic compounds. Pentylenetetrazole- (PTZ) and pilocarpine-induced seizures are well-established models of human epilepsy. Generally, PTZ or pilocarpine has been used to produce seizures in experimental models. In this study, we explored the possibility of creating new epilepsy and seizure models by co-administration of PTZ and pilocarpine. METHODS: The protocol was divided into three parts: A) Kindling experiments: the animals received PTZ or co-administration doses of PTZ and pilocarpine every other day for a period of 26 days. B) Seizure experiments, for induction of seizure, the animals received one dose of PTZ, pilocarpine or co-administration doses of PTZ and pilocarpine. C) Evaluation of antiepileptic drugs: the animals received phenytoin or sodium valproate 20 min before injection of PTZ, pilocarpine or co-administration doses of PTZ and pilocarpine. RESULTS: The co-administration of pilocarpine and PTZ could induce seizure, which has behavioral similarity between electrical and chemical kindling. Pilocarpine (50 mg/kg) + PTZ (37.5 mg/kg) was the appropriate dose for kindling induction. Animals with this dose reached the stage five seizures significantly faster than those with PTZ alone. Unlike the seizure induced by PTZ, or pilocarpine, induction of seizure by PTZ + pilocarpine was resistant to phenytoin and sodium valproate treatment. As compared to the PTZ model of kindling, this model visualized the seizure behavior better and had resistance to two most popular antiepileptic drugs. CONCLUSION: Our results indicated that co-administration of pilocarpine and PTZ could provide a new modified model of seizure and kindling resisting to phenytoin and sodium valproate.

Pupillometry in Chagas disease.

PURPOSE: We investigated parasympathetic innervation abnormalities of the iris sphincter and ciliary muscles in chronic Chagas disease by measuring pupillary diameter and intraocular pressure. METHODS: A group of 80 patients with Chagas disease was compared with 76 healthy individuals without chagasic infection. The following procedures were performed: pupillometry, hypersensitivity test to pilocarpine 0.125%, intraocular pressure measurement (IOP), basal pupil diameter (BPD), absolute pupillary constriction amplitude (ACA), relative pupillary constriction amplitude (RCA) and the presence of anisocoria. RESULTS: The prevalence of anisocoria was higher in chagasic patients (p<0.01). These patients had mean basal pupillary diameter, mean photopic pupillary diameter and mean value of absolute pupillary constriction amplitude significantly lower than non-chagasic ones (p<0.01, mean difference -0.50mm), (p=0.02, mean difference -0.20mm), (p<0.01, mean difference -0.29mm), respectively. The relative pupillary constriction amplitude did not differ between the two groups (p=0.39, mean difference -1.15%). There was hypersensitivity to dilute pilocarpine in 8 (10%) of the chagasic patients in the right eye and in 2 (2.5%) in the left eye and in 1 (1.25%) in both eyes. The mean value of intraocular pressure had a marginal statistical significance between the two groups (p=0.06, mean difference -0.91mmHg). CONCLUSIONS: Patients with chagasic infection may exhibit ocular parasympathetic dysfunction, demonstrable by pupillometry and the dilute pilocarpine hypersensitivity test.

Pupillometry in Chagas disease / Pupilometria na doença de Chagas

ABSTRACT Purpose: We investigated parasympathetic innervation abnormalities of the iris sphincter and ciliary muscles in chronic Chagas disease by measuring pupillary diameter and intraocular pressure. Methods: A group of 80 patients with Chagas disease was compared with 76 healthy individuals without chagasic infection. The following procedures were performed: pupillometry, hypersensitivity test to pilocarpine 0.125%, intraocular pressure measurement (IOP), basal pupil diameter (BPD), absolute pupillary constriction amplitude (ACA), relative pupillary constriction amplitude (RCA) and the presence of anisocoria. Results: The prevalence of anisocoria was higher in chagasic patients (p<0.01). These patients had mean basal pupillary diameter, mean photopic pupillary diameter and mean value of absolute pupillary constriction amplitude significantly lower than non-chagasic ones (p<0.01, mean difference -0.50mm), (p=0.02, mean difference -0.20mm), (p<0.01, mean difference -0.29mm), respectively. The relative pupillary constriction amplitude did not differ between the two groups (p=0.39, mean difference -1.15%). There was hypersensitivity to dilute pilocarpine in 8 (10%) of the chagasic patients in the right eye and in 2 (2.5%) in the left eye and in 1 (1.25%) in both eyes. The mean value of intraocular pressure had a marginal statistical significance between the two groups (p=0.06, mean difference -0.91mmHg). Conclusions: Patients with chagasic infection may exhibit ocular parasympathetic dysfunction, demonstrable by pupillometry and the dilute pilocarpine hypersensitivity test.

RESUMO Introdução: Investigaram-se anormalidades da inervação parassimpática dos músculos esfíncter da íris e ciliar na doença de Chagas crônica, através de medidas pupilares e da pressão intraocular. Métodos: Foram estudados dois grupos, um com 80 chagásicos e outro com 76 indivíduos saudáveis sem infecção chagásica. Foram realizados os seguintes procedimentos: pupilometria, teste de hipersensibilidade à pilocarpina a 0,125%, medida da pressão intraocular (PIO), diâmetro basal da pupila (DBP), amplitude de constrição pupilar absoluta (ACA), amplitude de constrição pupilar relativa (ACR), e presença de anisocoria. Resultados: A prevalência de anisocoria foi maior nos chagásicos (p<0,01). Estes pacientes apresentaram diâmetro basal pupilar médio, diâmetro fotópico médio e valor médio da amplitude de constrição pupilar absoluta, significativamente menores que os não chagásicos, (p<0,01, diferença de média -0,50mm), (p=0.02, diferença de média -0,20mm), (p<0,01, diferença de média -0,29mm), respectivamente. A amplitude de constrição pupilar relativa não diferiu entre os dois grupos (p=0,39, diferença de média -1,15%). Houve hipersensibilidade à pilocarpina diluída em 8 (10%) chagásicos no olho direito em 2 (2,5%) no olho esquerdo e em 1 (1,25%) em ambos os olhos. O valor médio da pressão intraocular teve significância marginal entre os dois grupos (p=0,06, diferença de média -0,91mmHg). Conclusões: Pacientes com infecção chagásica podem apresentar disfunção parassimpática ocular, demonstrável pela pupilometria e pelo teste de hipersensibilidade à pilocarpina diluída.

The Pilocarpine Model of Temporal Lobe Epilepsy and EEG Monitoring Using Radiotelemetry System in Mice.

Temporal lobe epilepsy (TLE) is a common neurological disorder in adulthood. For translational studies of chronic epilepsy, pilocarpine-induced status epilepticus (SE) is frequently selected to recapitulate spontaneous recurrent seizures (SRS). Here we present a protocol of SE induction by intraperitoneal (i.p.) injection of pilocarpine and monitoring of chronic recurring seizures in live animals using a wireless telemetry video and electroencephalogram (EEG) system. We demonstrated notable behavioral changes that need attention after pilocarpine injection and their correlation with hippocampal neuronal loss at 7 days and 6 weeks post-pilocarpine. We also describe the experimental procedures of electrode implantation for video and EEG recording, and analysis of the frequency and duration of chronic recurrent seizures. Finally, we discuss the possible reasons why the expected results are not achieved in each case. This provides a basic overview of modeling chronic epilepsy in mice and guidelines for troubleshooting. We believe this protocol can serve as a baseline for suitable models of chronic epilepsy and epileptogenesis.

Acetylcholine chloride 1% usage for intraoperative cataract surgery miosis / Cloridrato de Acetilcolina 1% na obtenção da miose intraoperatória na cirurgia de catarata

Abstract Objective: To test the efficacy of Acetylcholine chloride use in obtaining intraoperative miosis on phacoemulsification cataract surgery. Methods: Patients with cataract diagnosis and elected for surgical phacoemulsification procedure were selected. All patients underwent conventional phacoemulsification procedure performed by a single surgeon and all patients had 0.2 ml of Acetylcholine chloride 1% irrigated in the anterior chamber at the end of the surgery. The pupillary diameter was measured immediately before the beginning of surgery, immediately before and two minutes after the use of acetylcholine chloride 1%. Results: A total of 30 eyes from 30 patients were included in the study. 18 were female, and mean age was of 69.5 years with a 7.2y standard deviation on the population study. The mean pupillary diameter immediately before the beginning of surgery was 7.5 mm with a standard deviation of 0.56 mm; the mean pupillary diameter immediately before the acetylcholine chloride 1% use (after the intraocular lens im-plantation) was 7.1 mm with a standard deviation of 0.57 mm. The mean pupillary diameter two minutes after the use of acetylcholine chloride 1% in the anterior chamber was 3.4 mm with standard deviation of 0.66 mm. The mean maximum action time of ACH chloride 1% was 64 seconds, with a standard deviation of 8 seconds. The mean intraocular pressure on the first postoperative day was 19.1 mmHg with a standard deviation of 2.45 mmHg. Conclusion: We conclude that acetylcholine chloride 1% is an important drug to obtaining intraoperative miosis in cataract surgery.

Resumo Objetivo: Demonstrar a eficácia do cloridrato de acetilcolina 1% na obtenção da miose intraoperatória na cirurgia de catarata pela técnica de facoemulsificação. Métodos: Pacientes com diagnóstico de catarata e indicação de cirurgia foram selecionados para participar do presente estudo. Todos os pacientes foram operados pela técnica de facoemulsificação convencional pelo mesmo cirurgião, todos foram submetidos à aplicação de 0,2 ml do cloridrato de acetilcolina 1% na câmara anterior ao final do procedimento cirúrgico. A medida do diâmetro pupilar foi realizada imediatamente antes do início da cirurgia, imediatamente antes do uso do cloridrato de acetilcolina 1% e após 2 minutos. Resultados: Foram estudados 30 olhos de 30 pacientes, destes, 18 eram do sexo feminino, a média de idade do estudo foi de 69,5 anos com desvio padrão de 7,2 anos. A média do diâmetro pupilar imediatamente antes do início da cirurgia foi 7,55 mm com desvio padrão de 0,56mm, a média do diâmetro pupilar imediatamente antes do uso do cloridrato de acetilcolina 1% (após implante da lente intraocular no saco capsular) foi 7,1mm com desvio padrão de 0,57mm. A média do diâmetro pupilar após 2 minutos da aplicação da acetilcolina na câmara anterior foi de 3,4 mm com desvio padrão de 0,66mm. O tempo médio de ação máxima do medicamento foi de 64 segundos, com desvio padrão de 8 segundos. A média da pressão intraocular no primeiro dia do pós-operatório foi de 19,1 mmHg com desvio padrão de 2,45mmHg. Conclusão: O estudo acima mostrou que a acetilcolina apresenta boa eficácia na obtenção de miose intraoperatória na cirurgia de facoemulsificação, permitindo uma maior facilidade na confecções das suturas corneanas ou corneo-escleral, reduzindo a incidência de sinéquias anteriores periféricas. Concluimos que o cloridrato de acetilcolina 1% é um importante medicamento na obtenção da miose intraoperatória na cirurgia de catarata.

Relative Antagonism of Mutants of the CGRP Receptor Extracellular Loop 2 Domain (ECL2) Using a Truncated Competitive Antagonist (CGRP8-37): Evidence for the Dual Involvement of ECL2 in the Two-Domain Binding Model.

The second extracellular loop (ECL2) of the G protein-coupled receptor (GPCR) family is important for ligand interaction and drug discovery. ECL2 of the family B cardioprotective calcitonin gene-related peptide (CGRP) receptor is required for cell signaling. Family B GPCR ligands have two regions; the N-terminus mediates receptor activation, and the remainder confers high-affinity binding. Comparing antagonism of CGRP8-37 at a number of point mutations of ECL2 of the CGRP receptor, we show that the ECL2 potentially facilitates interaction with up to the 18 N-terminal residues of CGRP. This has implications for understanding family B GPCR activation and for drug design at the CGRP receptor.

Methods for determining time of death.

Medicolegal death time estimation must estimate the time since death reliably. Reliability can only be provided empirically by statistical analysis of errors in field studies. Determining the time since death requires the calculation of measurable data along a time-dependent curve back to the starting point. Various methods are used to estimate the time since death. The current gold standard for death time estimation is a previously established nomogram method based on the two-exponential model of body cooling. Great experimental and practical achievements have been realized using this nomogram method. To reduce the margin of error of the nomogram method, a compound method was developed based on electrical and mechanical excitability of skeletal muscle, pharmacological excitability of the iris, rigor mortis, and postmortem lividity. Further increasing the accuracy of death time estimation involves the development of conditional probability distributions for death time estimation based on the compound method. Although many studies have evaluated chemical methods of death time estimation, such methods play a marginal role in daily forensic practice. However, increased precision of death time estimation has recently been achieved by considering various influencing factors (i.e., preexisting diseases, duration of terminal episode, and ambient temperature). Putrefactive changes may be used for death time estimation in water-immersed bodies. Furthermore, recently developed technologies, such as H magnetic resonance spectroscopy, can be used to quantitatively study decompositional changes. This review addresses the gold standard method of death time estimation in forensic practice and promising technological and scientific developments in the field.

Improved Presbyopic Vision With Miotics.

OBJECTIVE: To evaluate the efficacy of using a parasympathomimetic drug (carbachol) with an alpha agonist (brimonidine) to create optically beneficial miosis to reduce the effect of presbyopia. METHODS: In this prospective, double-masked, randomized, placebo-controlled clinical trial, 48 naturally emmetropic and presbyopic subjects aged between 43 and 56 years with an uncorrected distance visual acuity of at least 20/20 in both eyes without additional ocular pathology were eligible for inclusion. Subjects were divided into 2 groups. The treatment group (n=30 eyes) received single dose of 2.25% carbachol plus 0.2% brimonidine eye drops. The control group (n=18 eyes) received placebo drops. Drops were given to all subjects in a masked fashion, in their nondominant eye. The minimum posttreatment follow-up was 3 months. The subjects' pupil size and both near and distance visual acuities were evaluated before and after treatment at 1, 2, 4, 8, and 10 hr, by a masked examiner at the same room illumination. RESULTS: Statistically significant improvement in near visual acuity was achieved in all subjects who received carbachol plus brimonidine drops (P<0.0001). In this masked study, all subjects liked and would use this therapy if it was available. None would use the placebo. There was no evidence of tolerance or tachyphylaxis during the study period. CONCLUSIONS: Improving the depth of focus by making the pupil smaller caused statistically significant improvement in near visual acuity in emmetropic presbyopic subjects. Carbachol plus brimonidine seem to be an acceptable and safe alternative to corrective lenses and surgical procedures.

Effects of muscarinic receptor modulators on ocular biometry of guinea pigs.

PURPOSE: This study investigated whether pilocarpine and cyclopentolate induce changes in ocular biometry of guinea pigs, in order to understand if guinea pigs have a similar response to these two agents as humans do. METHODS: Under general anaesthesia, refraction, axial components and surface curvature in various optical interfaces of the eye were measured in 10 guinea pigs (age of 2 weeks) at baseline (0 min) and different time points (5, 10, 20, 30, 60, 90 min) after topical administration of pilocarpine or cyclopentolate. The interval between the two drug treatments for the same animals was at least 24 h. RESULTS: Eyes treated with pilocarpine developed approximately 6D myopia (p < 0.001 from 0 to 90 min) with a decrease in anterior lens radius of curvature (ALRC) (p < 0.001 from 0 to 90 min, repeated measures anova). This myopic shift was moderately correlated to the decreased ALRC (r(2)  = 0.48, p < 0.001). Furthermore, a small but significant increase in the VCD (p < 0.001 from 0 to 30 min, repeated measures anova) with an unchanged AL (p = 0.85 from 0 to 90 min, repeated measures anova) after the drug treatment suggested a transient and mild forward movement of the lens. Cyclopentolate dilated the pupil in all eyes (p < 0.001 from 0 to 90 min, repeated measures anova) but did not change other ocular parameters. CONCLUSIONS: The muscarinic agonist, pilocarpine induced a myopic shift mainly due to a decrease in ALRC, suggesting that guinea pigs have an accommodative mechanism similar to that in humans. The minimal changes produced by cyclopentolate could be due to the use of general anaesthesia, which may have reduced the susceptibility of the eye to topical cyclopentolate in the induction of cycloplegia.

Evaluation of iridociliary and lenticular elasticity using shear-wave elastography in rabbit eyes.

INTRODUCTION: A previous study has employed shear-wave ultrasound elastographic imaging to assess corneal rigidity in an ex-vivo porcine eye model. This study employs the same modality in vivo in a rabbit eye model in order to assess lens, ciliary body and total ocular rigidity changes following the instillation of atropine and pilocarpine. METHODS: Ten non-pigmented female rabbits were examined. Measurements of the lens, ciliary body and total ocular rigidity as well as lens thickness and anterior chamber depth were taken with the Aixplorer system (SuperSonic Imagine, Aix-en-Provence, France) with the SuperLinear™ SL 15-4 transducer in both eyes at baseline as well as after pilocarpine and atropine instillation. The IOP was also measured with the TonoPen tonometer. RESULTS: Changes in rigidity in the examined areas following atropine instillation were statistically not significant. Ciliary body rigidity was significantly increased whereas lens and total ocular rigidity were significantly reduced following pilocarpine instillation. The decrease in lens rigidity following pilocarpine was significantly associated with the respective increase in ciliary body rigidity. CONCLUSIONS: Shear-wave ultrasound elastography can detect in vivo rigidity changes in the anterior segment of the rabbit eye model and may potentially be applied in human eyes, providing useful clinical information on conditions in which rigidity changes play an important role, such as glaucoma, pseudoexfoliation syndrome or presbyopia.

Morphological alterations within the peripheral fixation of the iris dilator muscle in eyes with pigmentary glaucoma.

PURPOSE: To analyze the peripheral fixation of the iris dilator muscle in normal eyes and in eyes with pigmentary glaucoma (PG). METHODS: Using 63 control eyes (age 18 months-99 years), the peripheral iris dilator was investigated by light microscopy, immunohistochemistry, and electron microscopy. Development was studied using 18 differently aged fetal eyes stained immunohistochemically against α-smooth muscle (SM) actin. The peripheral iris dilator muscle in PG was analyzed using semithin and ultrathin sections of six glutaraldehyde-fixed eyes from three donors aged 38, 62, and 74 years. RESULTS: In normal eyes, the peripheral end of the iris dilator muscle is arranged in a sphincter-like manner. Arcade-shaped tendinous connections associated with myofibroblasts (iridial strands) anchor the iris dilator within the elastic-fibromuscular ciliary meshwork that also serves as fixation area for the elastic tendons of the inner ciliary muscle portions. The iridial strands are innervated and can adapt their length during accommodation. The PG eyes show incomplete circular bundles and iridial strands that are mainly anchored to the iris stroma and the flexible uveal parts of the trabecular meshwork. CONCLUSIONS: The normal anchorage of the peripheral iris dilator and its presumably neuronally regulated length adaptation stabilize the peripheral iris during accommodation. Insufficient fixation in PG could promote posterior bowing of the iris with rubbing against the zonular fibers and pigment liberation from the iris pigmented epithelium.

Intermedin in paraventricular nucleus attenuates sympathetic activity and blood pressure via nitric oxide in hypertensive rats.

Intermedin (IMD) is a member of calcitonin/calcitonin gene-related peptide family, which shares the receptor system consisting of calcitonin receptor-like receptor (CRLR) and receptor activity-modifying proteins (RAMPs). This study investigated the effects of IMD in paraventricular nucleus (PVN) on renal sympathetic nerve activity and mean arterial pressure and its downstream mechanism in hypertension. Rats were subjected to 2-kidney 1-clip (2K1C) surgery to induce renovascular hypertension or sham operation. Acute experiments were performed 4 weeks later under anesthesia. IMD mRNA and protein were downregulated in 2K1C rats. Bilateral PVN microinjection of IMD caused greater decreases in renal sympathetic nerve activity and mean arterial pressure in 2K1C rats than in sham-operated rats, which were prevented by pretreatment with adrenomedullin receptor antagonist AM22-52 or nonselective nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester, and attenuated by selective neuronal NO synthase inhibitor N(ω)-propyl-l-arginine hydrochloride or endothelial NO synthase inhibitor N(5)-(1-iminoethyl)-l-ornithine dihydrochloride. AM22-52 increased renal sympathetic nerve activity and mean arterial pressure in 2K1C rats but not in sham-operated rats, whereas calcitonin/calcitonin gene-related peptide receptor antagonist calcitonin/calcitonin gene-related peptide 8-37 had no significant effect. CRLR and RAMP3 mRNA, as well as CRLR, RAMP2, and RAMP3 protein expressions, in the PVN were increased in 2K1C rats. Microinjection of IMD into the PVN increased the NO metabolites (NOx) level in the PVN in 2K1C rats, which was prevented by AM22-52. Chronic PVN infusion of IMD reduced, but AM22-52 increased, blood pressure in conscious 2K1C rats. These results indicate that IMD in the PVN inhibits sympathetic activity and attenuates hypertension in 2K1C rats, which are mediated by adrenomedullin receptors (CRLR/RAMP2 or CRLR/RAMP3) and its downstream NO.

Biodegradable in situ gelling delivery systems containing pilocarpine as new antiglaucoma formulations: effect of a mercaptoacetic acid/N-isopropylacrylamide molar ratio.

Ocular drug delivery is one of the most commonly used treatment modalities in the management of glaucoma. We have recently proposed the use of gelatin and poly(N-isopropylacrylamide) (PNIPAAm) graft copolymers as biodegradable in situ forming delivery systems for the intracameral administration of antiglaucoma medications. In this study, we further investigated the influence of carrier characteristics on drug delivery performance. The carboxyl-terminated PNIPAAm samples with different molecular weights were synthesized by varying the molar ratio of mercaptoacetic acid (MAA)/N-isopropylacrylamide (NIPAAm) from 0.05 to 1.25, and were determined by end-group titration. The preparation of gelatin-g-PNIPAAm (GN) copolymers from these thermoresponsive polymers was achieved using carbodiimide chemistry. Our results showed that the carboxylic end-capped PNIPAAm of high molecular weight may lead to the lower thermal phase transition temperature and slower degradation rate of GN vehicles than its low molecular weight counterparts. With a decreasing MAA/NIPAAm molar ratio, the drug encapsulation efficiency of copolymers was increased due to fast temperature-triggered capture of pilocarpine nitrate. The degradation of the gelatin network could greatly affect the drug release profiles. All of the GN copolymeric carriers demonstrated good corneal endothelial cell and tissue compatibility. It is concluded that different types of GN-based delivery systems exhibit noticeably distinct intraocular pressure-lowering effect and miosis action, thereby reflecting the potential value of a MAA/NIPAAm molar ratio in the development of new antiglaucoma formulations.

Urrets- Zavalia Syndrome after glaucoma filtration device implantation.

We report a case of Urrets-Zavalia Syndrome after a glaucoma filtration device (g.f.d.) implantation. A 74-year-old woman with bilateral advanced glaucoma has been planned for surgery. The patient underwent to g.f.d. implantation in the right eye. On postoperative day 1, the patient had an edematous cornea with a dilated and non reactive pupil. In this article we describe the clinical history of this patient. To our knowledge, this is the first case of Urrets-Zavalia Syndrome after a g.f.d. implantation.

The role of caveolae in regulating calcitonin receptor-like receptor subcellular distribution in vascular smooth muscle cells.

To determine whether caveolae and caveolin-1 affect the distribution of calcitonin receptor-like receptors (CLR) in vascular smooth muscle cell (VSMC) membranes, we have used VSMCs cell line A10. We found that calcitonin gene-related peptide (CGRP) reduced CLR protein in the VSMC membrane in a time-dependent manner, which was dramatically decreased after 4 h CGRP treatment, and remained at a low level after 16 h. CGRP8-37 or ß-cyclodextrin (ß-CD) blocked this effect, without changing the total levels of CLR protein and mRNA in the cells. Co-immunoprecipitation experiments showed that CLR bound to caveolin-1 in cell membrane fractions. Confocal laser microscopic studies confirmed this co-localization relationship at the cell plasma membrane. Thus, our data indicate that the structural integrity of caveolae plays an important role in regulating subcellular distribution of CLR.