Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “IRIS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 163 records · Page 9Linked to original sources
PubMed1995

[Effect of traumatic iris defects on spatial perception].

Perforating injury to the eye often results in iris defects in addition to loss of the lens. To determine whether iris defects can impair stereopsis, we tested the stereoscopic vision of 23 patients treated at the University Eye Clinic in Kiel for perforating eye injuries involving the iris and, in most cases, the lens. The patients were divided into three groups according to the severity of the iris defect and the status of the intraocular lens. Individuals with strabismus or visual acuity < 0.5 (20/40) were excluded. Stereopsis was measured using conventional stereopsis tests (Titmus contour stereopsis, Lang global stereopsis) and by means of the Pulfrich pendulum phenomenon. Patients with traumatic aphakia without an iris defect (n = 33) served as controls. Optical rehabilitation was achieved in the controls lenses (n = 16) or intraocular lens implant (n = 17). In group I (intact lens, iris defect < 135 degrees), two of five patients had attained global stereopsis. In group II (implanted or contact lens, iris defect < 135 degrees), only one of the nine patients exhibited global stereopsis. In group III (no lens, iris defect > 135 degrees), none of the nine patients achieved global stereopsis. In the control group, by contrast, more than half of the patients with an implant (10 of 17) and 3 of 16 patients with a contact lens attained global stereopsis. The results indicate that severe iris defects are especially likely to impair stereoscopic vision, more so than traumatic loss of lens alone without an accompanying iris defect.

Adolescent↗
PubMed1996

Iris mammillations: significance and associations.

Iris mammillations are rarely described, distinctive villiform protuberances that can cover the iris. In the majority of reported cases they are unilateral and sporadic, and are seen in association with oculodermal melanosis. In past literature and current clinical practice they are frequently confused with the iris nodules seen in neurofibromatosis type 1. Their clinical significance is not established, although it has been suggested that iris mammillations may be an external sign of ocular hypertension or intraocular malignancy. We report a series of 9 patients between the ages of 3 and 28 years with iris mammillations. The mammillations appear as regularly spaced, deep brown, smooth, conical elevations on the iris, of uniform height or increasing in height as the pupil margin is approached. They often overlie a naevus or an exceptionally deeply pigmented iris, such as that seen in melanosis oculi. One case had an associated ciliary body mass. They tend to occur in more highly pigmented ethnic groups and can be dominantly inherited. Iris mammillations may occur in association with systemic conditions including phakomatosis pigmentovascularis type IIb and neurofibromatosis type 1 when they may even coexist with iris hamartomas.

Adult↗
PubMedDate not supplied

Iris melanocytoma mimicking the Cogan-Reese syndrome with monocular pigment dissemination.

PURPOSE: To report a case of iris melanocytoma mimicking the Cogan-Reese syndrome. METHODS: A 37-year-old woman presented with pigmentary glaucoma in her left eye. There was diffuse pigmentary dispersion in the anterior segment, pedunculated pigmented nodules on the anterior iris surface, mild iris atrophy, and ectropion iridis. Neither intrinsic vasculature nor a sector cataract was found. The angle was open with marked trabecular pigmentation and no anterior synechiae. The intraocular pressure was 30 mmHg with maximum medical treatment and there was glaucomatous optic atrophy. The differential diagnosis included iris pigmented tumor and iridocorneal endothelial syndrome (Cogan-Reese syndrome). An iris biopsy was performed for diagnostic purposes. RESULTS: Histologic diagnosis after evaluation of the specimen was iris melanocytoma. CONCLUSIONS: This case presents signs considered quasi-pathognomonic of iridocorneal endothelial syndrome (Cogan-Reese syndrome): glaucoma, mild iris atrophy associated with pedunculated iris nodules, and ectropion iridis. Therefore, iris melanocytoma can present with features that mimic the Cogan-Reese syndrome.

Adult↗
PubMed2001

Modeling passive mechanical interaction between aqueous humor and iris.

Certain forms of glaucoma are associated with displacement of the iris from its normal contour. We present here a mathematical model of the coupled aqueous humor-iris system that accountsfor the contribution of aqueous humor flow and passive iris deformability to the iris contour. The aqueous humor is modeled as a Newtonian fluid, and the iris is modeled as a linear elastic solid. The resulting coupled equation set is solved by the finite element method with mesh motion in response to iris displacement accomplished by tracking a pseudo-solid overlying the aqueous humor. The model is used to predict the iris contour in healthy and diseased eyes. The results compare favorably with clinical observations, supporting the hypothesis that passive iris deformation can produce the iris contours observed using ultrasound biomicroscopy.

Aqueous Humor↗
PubMed1996

Iris indocyanine green videoangiography in diabetic iridopathy.

AIMS/BACKGROUND: Iris fluorescein angiography (IFA) is not commonly used in clinical practice, although its value has been demonstrated especially in cases of diabetic disease. IFA is able to show neovascular tufts in order to guide the laser treatment, and it is highly recommended in diabetic patients who need cataract surgery or vitrectomy. Nevertheless, IFA fails to demonstrate the iris vascular pattern in heavily pigmented iris and conspicuous leakage cases. The aim of the study was to evaluate the feasibility of iris indocyanine green videoangiography (IICGV) and to correlate its findings with those of IFA in diabetic iridopathy. METHODS: Thirty six patients affected in varying degrees by diabetic retinopathy underwent an ophthalmic examination including retinal fluorescein angiography, IFA, and IICGV. IICGV was performed using IMAGEnet System H1024. RESULTS: The results demonstrated that IICGV allows precise visualisation of the iris vascular pattern, also in cases of heavily pigmented iris. CONCLUSIONS: Three main findings seemed to be evident: firstly, iris neovascularisations are detected with IFA far more easily than IICGV; secondly, capillary dilatations and iris hypoperfusion are identified far more clearly using IICGV; thirdly, there is no evident relation between capillary dilatation or iris hypoperfusion, and degree of diabetic retinopathy.

Aged↗
PubMed1999

Adenoma of the iris pigment epithelium: a report of 20 cases: the 1998 Pan-American Lecture.

BACKGROUND: Adenoma of the iris pigment epithelium (IPE) is an uncommon lesion that can simulate iris or ciliary body melanoma, melanocytoma, and pigment epithelial cyst. OBJECTIVES: To evaluate the clinical and pathological features and prognosis of adenoma of the IPE in patients managed by us and to elucidate the features that help to differentiate this tumor from iris melanoma and other similar conditions. PATIENTS AND METHODS: The medical records of 20 patients with adenoma of the IPE were reviewed, and the clinical and histopathologic features were tabulated. RESULTS: Ten patients were male and 10 were female, with a mean age of 60.0 years (range, 11-85 years). All patients were referred because of suspected iris or ciliary body melanoma. All lesions were solitary and unilateral. Sixteen were located in the peripheral iris; 2, in the midzone; and 2, near the pupillary margin. Clinically, all tumors were abruptly elevated, all but 1 were dark gray to black, and all had a smooth, but sometimes multinodular, surface. The tumors caused thinning or complete effacement of the overlying iris stroma, but they did not directly involve the stroma. They typically blocked light with transillumination. On ultrasound biomicroscopy findings, adenoma of the IPE shows a solid tumor pattern, sometimes with small cystoid spaces. The tumor was managed by local resection in 2 patients and observation in 18, all of whom have been stable, with follow-up ranging from 6 months to 9 years. Histopathologic examination revealed a tumor originating in the IPE consisting of cords of pigment epithelial cells separated by septae of connective tissue. CONCLUSIONS: Adenoma of the IPE usually has characteristic features that should differentiate it from iris melanoma, ciliary body melanoma, iris melanocytoma, and iris cyst. Adenoma of the IPE is a benign tumor that may remain relatively stable for years.

Adenoma↗
PubMed1990

Macrophage mobilization and morphology during lens regeneration from the iris epithelium in newts: studies with correlated scanning and transmission electron microscopy.

The lens was removed from both eyes of adult newts (Notophthalmus viridescens), and the eyes were fixed in Karnovsky's fixative every 2 days 0-20 days after operation. Anterior half-eyes were prepared by standard procedures for scanning electron microscopy of the surface. Before fixation, the posterior iris surface was cleaned of adhering vitreous mechanically with forceps or by treatment with bovine testicular hyaluronidase or with hyaluronidase and collagenase. Some specimens were cryofractured in buffer or ethanol transverse to the mid-dorsal iris, and the fractured surface viewed with scanning electron microscopy (SEM). Cells with various combinations of ridges, blebs, filopodia, and lamellipodia were observed adhering to the posterior surface of the iris by 6 days after lentectomy. These cells, which exhibited the surface characteristics of macrophages, became more numerous in specimens fixed after longer intervals. Invasion of the iris epithelium was observed in a cryofractured specimen. After observations with SEM, selected specimens were embedded in plastic and sectioned for study with transmission electron microscopy (TEM). The cells on the iris surface had the cytological characteristics of macrophages, and other macrophages were located within the iris epithelium. In specimens fixed 16 or more days after lentectomy, a bulging lens vesicle was regenerating from the dorsal pupillary margin of the iris. Macrophages were absent or few on the surface of this developing lens but remained scattered over the adjoining iris. Roles that might be played by these macrophages during the transdifferentiation of iris epithelium into lens are discussed.

Animals↗
PubMed1987

Embryonic origin of skeletal muscle cells in the iris of the duck and quail.

The origin of skeletal muscle cells in avian iris muscle was investigated by quantitative analysis of heterochromatin profiles at the electron-microscopic level in irides of six types of quail-duck chimeras. Each of the following tissues was transplanted into the head region from quail to duck between stages 9 and 10: cranial neural crest; trunk neural crest; midbrain and adjacent mesoderm; forebrain; forebrain without neural crest; and forebrain without neural crest and mesoderm. The average ratio of heterochromatin profile to nucleus profile in iris skeletal muscle cells was high (quail type) in the dorsal iris, but low (duck type) in the ventral iris of the chimeras resulting from isotopic transplantation of cranial neural crest. Heterotopic transplantation of trunk neural crest to cranial position resulted in failure of development of skeletal muscle cells in the dorsal iris, but not in the appearance of skeletal muscle cells in the ventral iris. The average ratio of heterochromatin profile to nucleus profile in iris skeletal muscle cells was high in the chimeras resulting from transplantation of midbrain region and the chimeras resulting from transplantation of forebrain region, intermediate in the chimeras resulting from transplantation of forebrain region without neural crest, and low in the chimeras resulting from transplantation of forebrain region without neural crest and mesoderm. These results indicate that the skeletal muscle cells in the dorsal iris are of cranial neural crest origin while those in the ventral iris are not, and could possibly arise from cranial mesoderm.

Animals↗
PubMed2006

Determinative role of Wnt signals in dorsal iris-derived lens regeneration in newt eye.

We have previously shown that lens regeneration from the pigmented epithelium of the dorsal iris in the adult newt eye proceeds in two steps after lens removal or intraocular FGF2 injection. The FGF2-dependent proliferation of iris pigmented epithelium and activation of early lens genes that occur over the entire circumference of the iris comprise the first step, while subsequent dorsally confined lens development marks the second step. Here, we investigated the expression of Wnt and Wnt receptor Frizzled genes in lens-regenerating iris tissues. Wnt2b and Frizzled4 were activated only in the dorsal half of the iris in synchrony with the occurrence of the second step, whereas Wnt5a and Frizzled2 were activated in both halves throughout the period of the first and second steps. Cultured explants of the iris-derived pigmented epithelium in the presence of FGF2 underwent dorsal-specific lens development fully recapitulating the in vivo lens regeneration process. Under these conditions, Wnt inhibitors Dkk1, which specifically inhibits the canonical signal pathway, and/or sFRP1 repressed the lens development, while exogenous Wnt3a, which generally activates the canonical pathway like Wnt2b, stimulated lens development from the dorsal iris epithelium and even caused lens development from the ventral iris epithelium, albeit at a reduced rate. Wnt5a did not elicit lens development from the ventral epithelium. These observations indicate that dorsal-specific activation of Wnt2b determines the dorsally limited development of lens from the iris pigmented epithelium.

Animals↗
PubMed1994

Decreasing stromal iris pigmentation as a risk factor for age-related macular degeneration.

To evaluate iris color, change of iris color, and iris pigment epithelial defects as risk factors in age-related macular degeneration, we compared 101 patients with age-related macular changes with 102 control subjects in a case-control study. Three of 101 patients (3%) and four of 102 control subjects (4%) had epithelial iris defects. Light iris color during youth was reported by 51 of 101 patients (50.5%) and 42 of 102 control subjects (41.2%) (odds ratio, 1.46; P = .184). Of the 101 patients, 26 (25.7%) noticed their iris color to have become lighter during life compared with six of 102 control subjects (5.9%) (odds ratio, 5.5; P = .0001). At present examination, 63 of 101 patients (62.4%) had light irides compared with 43 of 102 control subjects (42.2%) (odds ratio, 2.27; P = .004). These results suggest that initial light iris color and iris pigment epithelial defects are not associated with an increased risk of age-related macular degeneration, whereas decreased stromal iris pigmentation may indicate a higher risk.

Aged↗
PubMed1992

Nucleolar organizer regions in iris nevi and melanomas.

The silver staining of nucleolar organizer region-associated proteins is an objective method that has been used to differentiate benign from malignant neoplasms. Recently this method was used to distinguish benign choroidal nevi from malignant choroidal melanomas. We studied 24 iris melanocytic lesions to assess the applicability of this technique for differentiating benign from neoplastic iris tumors. Masked observers determined the number of silver-stained nucleolar organizer region dots per cell for silver-stained specimens. Iris nevi contained a mean of 1.6 silver-stained nucleolar organizer region dots per cell, whereas iris (spindle A and B, spindle B, epithelioid, mixed cell) malignant melanomas contained a mean of at least 3.5 silver-stained nucleolar organizer region dots per cell (P less than .0001). All iris nevi demonstrated counts lower than 1.9, whereas all iris melanomas demonstrated counts greater than 2.8. Silver-stained nucleolar organizer region counts were also compared with the clinicopathologic variables of gender, age, and largest specimen dimension. Only the largest specimen dimension correlated with silver-stained nucleolar organizer region counts (P less than .0029). The silver-stained nucleolar organizer region method is a simple technique for differentiating iris nevi from iris melanomas. The silver-stained nucleolar organizer region technique may aid in the assessment and treatment of iris lesions by confirming the malignancy of biopsy specimens.

Female↗
PubMed1998

Segmental denervation and reinnervation of the iris sphincter as shown by infrared videographic transillumination.

OBJECTIVE: This study aimed to analyze the denervation and reinnervation history of individual segments of the iris sphincter in patients with Adie's syndrome. DESIGN: The irises of these patients were retroilluminated by shining an infrared-rich light through the lower eyelid and sclera and viewing the transilluminated iris from the front with an infrared-sensitive video camera. The irises of the same group of patients also were videotaped through a slit-lamp camera using routine frontal illumination. Both of these techniques also were used to examine a series of normal subjects. PARTICIPANTS: A total of 61 patients with Adie's syndrome or Adie's-like denervation of the iris sphincter (from surgery, trauma, or radiation) and 10 normal subjects were studied. MAIN OUTCOME MEASURES: Slit-lamp examination results of the segmental movement of the iris were compared to the infrared transillumination pattern of the iris sphincter before and during the light reflex, before and during the near-vision reaction, before and during eye movement, and before and after the application of dilute pilocarpine and 1% pilocarpine. RESULTS: Whenever an iris sphincter segment contracted, it also became denser by using these techniques. Reinnervated iris segments failed to contract to light but did contract and became denser with a near effort or with eye movement. Segments supersensitive to pilocarpine became denser than adjacent segments without supersensitivity, but atrophic-appearing segments looked translucent and thin, failing to become denser, even with 1% pilocarpine. CONCLUSIONS: The innervational history and current status of each clock-hour segment of the iris sphincter can be determined using this technique of videographic infrared transillumination, and the progression and pattern of iris denervation and reinnervation can be determined in patients with Adie's pupil. A miotic Adie's pupil that is "tonic," even in darkness, was found to be associated with a dense pattern of infrared transillumination in sphincter segments, which the authors interpret as being associated with a rich reinnervation from accommodative fibers. Segments that become densely reinnervated appear to lose their cholinergic supersensitivity.

Adie Syndrome↗
PubMed2006

[Argon laser iridoplasty in the treatment of angle closure glaucoma with plateau iris syndrome].

INTRODUCTION: Plateau iris predisposes to the onset of an angle-closure glaucoma attack without pupillary block. This is a morphological anomaly of the iris characterized by anterior insertion, root thickness greater than the norm, and anterior rotation of the ciliary processes into the posterior chamber, pushing the base of the iris into the angle. Argon laser iridoplasty is useful to retract the peripheral iris using the thermal effect of the laser to widen the iridocorneal angle. MATERIALS AND METHODS: The study investigated nine eyes of five patients who had had iridoplasty for iris plateau angle-closure glaucoma, diagnosed by dynamic gonioscopy (or indentation gonioscopy) and confirmed by ultrasound biomicroscopy (UBM). There were four females and one male, with a mean age of 42.2 years (range, 30-53 years). The mean intraocular pressure (IOP) before iridoplasty was 21.1 mmHg. The number of antiglaucoma treatments was 1 or 2, with all patients receiving miotic treatment. All patients had undergone argon laser iridotomy beforehand to remove the pupillary block frequently associated with iris plateau. Iridoplasty was done in two sessions with postoperative IOP-lowering treatment. The laser parameters used were: duration, 0.3 s; power, 500 mW; diameter, 300 microm. RESULTS: The postoperative IOP evaluated at 1 month was 14.4 mmHg with a reduction in the hypotensive treatment. No treatment was prescribed for four eyes, a single hypotensive treatment for four eyes, and two hypotensive medications for one eye. DISCUSSION: Pure iris plateau syndrome, leading to closure of the angle, is very rare compared to pupillary block, but these two mechanisms often co-exist. The physiopathology explains that the mechanism of isolated iris plateau is not modified by iridectomy. However, the advantage of argon laser iridoplasty, which retracts the periphery of the iris so as to widen the iridocorneal angle, must be emphasized. This technique can alleviate the need for high-risk filtering surgery, but longer follow-up is necessary to evaluate its duration and efficacy.

Adult↗
PubMed2006

Phenotypic and immunoregulatory characteristics of monocytic iris cells.

The introduction of antigen into the anterior chamber of an eye induces the antigen-specific suppression of cell-mediated immunity and the antigen-induced production of immunoglobulin G2 antibodies. To define further the role of iris monocytic cells in the systemic suppression of cell-mediated immunity that follows the entry of foreign antigen into the anterior chamber, murine iris wholemounts or cell suspensions of iris cells were stained with fluorescent anti-F4/80 and/or anti-CD11c, anti-CD11b antibodies and examined by confocal microscopy or flow cytometry, respectively. Monocytic cells in iris cell suspensions were recovered from mice receiving an injection of trinitrophenylated bovine serum albumin (TNP-BSA) into an anterior chamber and Percoll-enriched iris cells separated into cells expressing F4/80 or CD11c were injected intravenously into TNP-BSA-immunized or naive recipients. The recipients were challenged to induce delayed-type hypersensitivity (DTH) or were provided with splenocytes or thymocytes that transfer the suppression of DTH. The homing of monocytic bone marrow cells to the iris was determined by the intravenous injection of bone marrow cells from green fluorescent protein (GFP)-transgenic donors into C57 mice, and the staining of recipient iris wholemounts with anti-F4/80 antibodies. Iris cells with a dendritic morphology expressing both F4/80 and/or CD11c and CD11b, some cells expressing only F4/80 or CD11c, were detected. The irides of irradiated GFP- mice that received intravenous GFP+ bone marrow cells contained GFP+ F4/80+ cells. F4/80+ and CD11c+ cells from the irides of donors that received intracameral TNP-BSA transferred the suppression of DTH when injected intravenously into TNP-BSA-immunized recipients, activated immunoregulatory thymocytes and activated antigen-specific splenic regulatory effector cells. These results support the hypothesis that iris monocytic cells may participate in the systemic induction of regulatory T cells.

Animals↗
PubMed2006

Iris atrophy in patients with newly diagnosed multibacillary leprosy: at diagnosis, during and after completion of multidrug treatment.

AIM: To describe the prevalence and incidence of iris atrophy in patients with multibacillary (MB) leprosy. METHODS AND PATIENTS: Prospective longitudinal cohort study. 301 newly diagnosed patients with MB leprosy were followed up during the 2 years of treatment with multidrug therapy (MDT) and for a further 5 years with biannual ocular examinations. Incidence of iris atrophy was calculated as the number of patients with iris atrophy per person-year (PY) of follow-up among those who did not have iris atrophy at baseline. Stepwise multiple regression confirmed the presence of specific associations of demographic and clinical characteristics (p<0.05) with iris atrophy, detected by univariate analysis. RESULTS: Iris atrophy was present in 6 (2%) patients at enrolment. During MDT, with 445 PYs of follow-up, 9 patients developed iris atrophy (IR 0.02, 95% CI 0.01 to 0.04) that was associated with cataract (HR 15.13, 95% CI 3.71 to 61.79, p<0.001) and corneal opacities (HR 6.83, 95% CI 1.62 to 28.8, p = 0.009). After MDT, with 2005 PYs of follow-up, 60 patients developed iris atrophy (IR 0.03, 95% CI 0.023 to 0.039) that was associated with age (per decade; HR 1.40, 95% CI 1.10 to 1.78, p = 0.006), skin smear positivity (HR 3.50, 95% CI 1.33 to 9.24, p = 0.011), cataract (HR 3.66, 95% CI 1.85 to 7.25, p<0.001), keratic precipitates (HR 2.76, 95% CI 1.02 to 7.47, p = 0.046) and corneal opacity (HR 3.95, 95% CI 1.86 to 8.38, p<0.001). CONCLUSIONS: Iris atrophy continues to develop in 3% of patients with MB leprosy every year after they complete a 2-year course of MDT, and is associated with age, increasing loads of mycobacteria, subclinical inflammation, cataract and corneal opacity.

Adolescent↗
PubMed2004

Iris recognition as a biometric method after cataract surgery.

BACKGROUND: Biometric methods are security technologies, which use human characteristics for personal identification. Iris recognition systems use iris textures as unique identifiers. This paper presents an analysis of the verification of iris identities after intra-ocular procedures, when individuals were enrolled before the surgery. METHODS: Fifty-five eyes from fifty-five patients had their irises enrolled before a cataract surgery was performed. They had their irises verified three times before and three times after the procedure, and the Hamming (mathematical) distance of each identification trial was determined, in a controlled ideal biometric environment. The mathematical difference between the iris code before and after the surgery was also compared to a subjective evaluation of the iris anatomy alteration by an experienced surgeon. RESULTS: A correlation between visible subjective iris texture alteration and mathematical difference was verified. We found only six cases in which the eye was no more recognizable, but these eyes were later reenrolled. The main anatomical changes that were found in the new impostor eyes are described. CONCLUSIONS: Cataract surgeries change iris textures in such a way that iris recognition systems, which perform mathematical comparisons of textural biometric features, are able to detect these changes and sometimes even discard a pre-enrolled iris considering it an impostor. In our study, re-enrollment proved to be a feasible procedure.

Algorithms↗
PubMed1999

Effects of adrenomedullin on cyclic AMP formation and on relaxation in iris sphincter smooth muscle.

PURPOSE: To determine whether iris sphincter and other tissues of the iris-ciliary body secrete adrenomedullin (ADM), a novel hypotensive peptide that is classified into the calcitonin gene-related peptide (CGRP) family and to determine the binding sites for ADM and compare the effects of ADM and CGRP in the absence and presence of their receptor antagonists on cAMP formation and relaxation in the iris sphincter. METHODS: Sphincter muscle was incubated in Krebs-Ringer bicarbonate buffer in the absence and presence of ADM for 10 minutes. Accumulation of cAMP in the tissue extract was determined by radioimmunoassay (RIA). The binding of [125I]ADM to iris sphincter membranes was carried out by rapid filtration. Distribution of ADM in the ocular tissues was determined by RIA. Changes in muscle tension were recorded isometrically. RESULTS: Immunoreactive ADM was present in all tissues of the cat iris-ciliary body. In the isolated cat iris sphincter, ADM increased cAMP accumulation in a time- (t1/2 = 2.2 minutes) and concentration- (EC50 = 13 nM) dependent manner, and this effect was sixfold more efficacious than CGRP. ADM, CGRP, vasoactive intestinal peptide, prostaglandin E2, isoproterenol, and forskolin increased cAMP formation in cat sphincter by 12.5-, 2-, 2.2-, 1-, 2.6-, and 2.4-fold, respectively. The rank of the effects of ADM on cAMP formation in iris sphincter isolated from different animal species was in the following order: cat > dog > bovine > human > rabbit. In the cat iris sphincter, the CGRP antagonist, CGRP(8 to 37), was more effective than the ADM antagonist, ADM (26 to 52), in inhibiting both ADM- and CGRP-induced cAMP formation. ADM and CGRP inhibited carbachol-induced contraction in a concentration-dependent manner with IC50 values of 10 and 90 nM, respectively. Both ADM and CGRP displaced the binding of [125I]ADM to sphincter membranes effectively, with IC50 values of 0.81 and 1.15 nM, respectively. CONCLUSIONS: In iris sphincter isolated from cat and other mammalian species including human, ADM is a much more efficacious activator of adenylate cyclase and a much more effective relaxant than CGRP. Its biological effects may be due to direct involvement of ADM receptors, but also to activation of CGRP receptors. Activation of ADM receptors by the peptide leads to concentration-dependent increases in cAMP accumulation and subsequent inhibition (relaxation) of smooth muscle contraction. These findings suggest a role for ADM as a local modulator of smooth muscle tone. A possible function for this potent hypotensive peptide in the regulation of intraocular pressure remains to be investigated.

Adenylyl Cyclases↗
PubMed1997

Quantitative real time measurement of iris configuration in human eyes.

PURPOSE: To evaluate intraobserver and interobserver reproducibility of real time measurement of iris morphology in living human eyes. METHODS: Based on the platform of software (Autocad, version 12), we developed an ultrasound biomicroscopy (UBM) image assistant measuring system. By using the system, we can perform the iris configuration quantitative measurement in living eyes. The measuring parameters including: iris rest length, radius of iris curvature, and the thickness in different parts of iris. Ten anterior segment images of one normal individual were obtained by a single operator to evaluate the intraobserver reproducibility of image capture, and ten times measurement of one image were performed by a single operator to assess the reproducibility of image measurement. The measurement of three independent observers were compared to investigate interobserver reproducibility in quantitative measurement. Intraobserver and interobserver reproducibility of measurement were assessed by calculating the coefficient of variation for each individual observer and by using the F test to detect a difference among observers. The iris configuration of 96 subjects (192 eyes) were measured. RESULTS: Intraobserver reproducibility was ranged from 0.9-4.9% in all measured parameters. Interobserver reproducibility for some of measured parameters varied considerably and was affected by subjective interpretative of visualized anatomic landmarks. The preliminary measured parameters in Chinese Show that iris rest length is 3.699 +/- 0.397 mm, radius of iris curvature is 9.101 +/- 1.408 mm, the average thickness of iris is 0.406 +/- 0.042 mm. CONCLUSION: The intraobserver reproducibility and the measured accuracy can fit the requisition of the ocular biometry and of the ocular physiology, pathophysiology, and pharmacology study. The method supply a new assistance for UBM image measurement.

Adult↗