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Somatostatin receptor gene expression in human ocular tissues: RT-PCR and immunohistochemical study.

PURPOSE: Somatostatin (SST) analogues have been used to treat proliferative diabetic retinopathy, pseudotumor cerebri, thyroid orbitopathy, and cystoid macular edema. There is a paucity of published data in regards to cell-specific distribution of SST receptors (SSTR) in normal human eye tissues. Gene expression for all five known SSTRs in normal human ciliary body/iris, retina, choroid, and cultured retinal pigment epithelial (RPE) cells were studied. METHODS: mRNA was isolated from human ocular tissues (iris/ciliary body, retina, and choroid) dissected from eight pairs of normal eyes (9-62 years) and from RPE cells grown in culture. RT-PCR was done for all five SSTRs in all analyzed tissues. Immunohistochemistry for SSTR1 and SSTR2 was performed on eight pairs of normal human eyes (28-74 years) imbedded in paraffin. RESULTS: SSTR1 to 5 genes are expressed in retina, SSTR1 and SSTR2 genes in cultured RPE cells, and SSTR1, 2, and 4 in ciliary body and choroid. SSTR1 and SSTR2 immunoreactivity (-ir) was observed on a variety of cells within all analyzed tissues including cornea, iris, trabecular meshwork, Schlemm's canal, ciliary processes, ciliary muscle, retina, choroid, cultured RPE cells, and optic nerve. CONCLUSIONS: SSTR genes are widely expressed in normal human eye tissues, with genes for SSTR1 and SSTR2 being the most widely expressed. Genes for all SSTRs are expressed in retina. SSTR1-ir and SSTR2-ir were observed in all analyzed ocular tissues. Detailed knowledge of SSTRs distribution and function in the human eye will result in a better understanding of their role in health and disease.

Adolescent↗

Increased elastin expression in astrocytes of the lamina cribrosa in response to elevated intraocular pressure.

PURPOSE: To determine whether abnormal elastin synthesis in the glaucomatous optic nerve head and lamina cribrosa is due to elevated intraocular pressure (IOP) or secondary to axonal injury, monkeys with elevated IOP and with optic nerve transection were compared. METHODS: Unilateral, chronic elevated IOP was induced in 11 rhesus monkeys by laser scarification of the trabecular meshwork. IOP was monitored weekly and maintained within 25 to 45 mm Hg for 7 to 36 weeks. In 6 monkeys, unilateral, optic nerve transection was performed, and monkeys were killed after 4 weeks. Optic nerve damage was assessed by stereoscopic slit-lamp biomicroscopy and fundus photography and by confocal scanning laser ophthalmoscopy. The eyes were enucleated and processed for immunohistochemistry and in situ hybridization and for electron microscopic immunogold detection of elastin. Axonal loss was evaluated in cross sections of the optic nerve stained with phenylenediamine. RESULTS: Compared with normal contralateral controls, the lamina cribrosa of eyes with elevated IOP exhibited markedly increased elastin and the presence of elastotic aggregates in the extracellular matrix and upregulation of elastin mRNA in the astrocytes. In transected eyes, elastin appeared as fine fibers in the lamina cribrosa, without elastotic aggregates, and without new synthesis or abnormal deposition of elastin. At the transected site, new synthesis of elastin was present in the pia mater but not in astrocytes in the glial scar. CONCLUSIONS: This study demonstrates that abnormal elastin synthesis in experimental glaucomatous optic neuropathy in the monkey is specific to elevated IOP and not secondary to axonal loss. The mechanisms by which elevated IOP induces enhanced elastin synthesis in laminar astrocytes are unknown but differ from those involved in acute axonal injury such as transection, where inflammation and breakdown of the blood-nerve barrier occur.

Animals↗

Gene mutation in patients with primary open-angle glaucoma in a pedigree in China.

OBJECTIVE: To investigate the genetic basis of the pathogenesis of a Guangzhou (GZ.1) pedigree with primary open-angle glaucoma (POAG). METHODS: DNA fragments of the trabecular meshwork inducible glucocorticoid response protein (TIGR) gene from 4 typical POAG patients and 2 normal subjects were amplified by polymerase chain reaction (PCR). The amplified PCR fragment was cloned into a pT-Adv vector, and direct sequencing was carried out on an ABI-373 automated DNA sequencer using dyeterminator chemistry to detect the mutation. RESULTS: The TIGR gene mutation was identified in the selected subjects of this pedigree. This mutation is a "C-to-T" transition at position 370, different from that of western countries and equivalent to the position change found in Japanese patients with familial POAG. No mutation was found in the TIGR gene fragment in 2 normal subjects of the pedigree. CONCLUSIONS: These preliminary results provide insights into the pathogenesis of POAG by the TIGR gene mutation, and into the underlying action of the different mutations in oriental and western peoples.

Cytoskeletal Proteins↗

Intraocular pressure reduction after selective laser trabeculoplasty in primary open angle glaucoma.

The aim of this prospective clinical study was to investigate the intraocular pressure (IOP) reduction after selective laser trabeculoplasty (SLT) in patients with primary open-angle glaucoma (POAG). SLT represents a new method in the treatment of POAG. Fifty eyes with uncontrolled POAG were treated with a frequency doubled, Q-switched Nd:YAG laser (532 nm). The pattern of treatment was applying approximately 50 burns to 180 degrees of the trabecular meshwork at energy levels ranging from 0.40-0.92 mJ per pulse. After SLT eyes were maintained with the identical hypotensive medical therapy as that before treatment. IOP was measured before treatment, 1 and 7 days after treatment and 1, 3, 6 and 12 months after treatment. The mean pretreatment IOP was 22.48 (SD 1.84) mm Hg. At the end of 1 month follow-up period the mean reduction of IOP was 4.86 (SD 2.38) mmHg or 21.6%; after 3 months the mean reduction was 5.66 (SD 2.40) mmHg or 25.2%; after 6 months the mean reduction of IOP was 5.06 (SD 2.37) mmHg or 22.5%; at the end of 12 months follow-up period the mean reduction was 4.92 (SD 2.58) mmHg or 21.9%. It can be concluded that SLT presents a new and effective method of IOP reduction in the treatment of POAG.

Aged↗

[A clinical evaluation of uveitis-associated secondary glaucoma].

PURPOSE: To investigate the clinical features of secondary glaucoma associated with uveitis. SUBJECTS AND METHODS: The subjects of the study were 1,604 eyes of 1,099 patients with uveitis at Miyata Eye Hospital, Miyakonojo, Miyazaki, between October 1974 and January 2000. The intraocular pressure (IOP) and clinical data were analyzed retrospectively. Secondary glaucoma was defined as being an IOP higher than 21 mmHg and needing treatment with medication to control the high IOP. RESULTS: Secondary glaucoma was found in 293 eyes (18.3%) of 217 patients (19.7%) among the uveitis patients. The clinical entity with the highest frequency of secondary glaucoma was Posner-Schlossman syndrome in 100%, followed by sarcoidosis in 34.1%, herpetic anterior uveitis in 30.4%, Behçet's disease in 20.8%, HLA-B 27 related acute anterior uveitis in 20.0%, Vogt-Koyanagi-Harada' disease in 16.4%, and HTLV-1 uveitis in 16.2%. Among the 293 eyes with secondary glaucoma, the majority (72%) had active anterior uveitis at the time of high IOP. Only 7.5% of secondary glaucoma eyes had peripheral anterior synechia wider than 180 degrees of trabecular meshwork. Steroid glaucoma was found only in 8.9% of the secondary glaucoma eyes. Surgical therapy mainly with trabeculectomy with anti-metabolites was performed in 38 eyes and the postsurgical IOP was controlled to 20 mmHg or lower in 36 eyes. Despite the medical and surgical therapy for secondary glaucoma, defect of the visual field was found in 38% of the secondary glaucoma eyes. CONCLUSIONS: The frequency of secondary glaucoma in 1,604 eyes with uveitis was 18.3%, and the frequency of secondary glaucoma differed depending upon the clinical entity of uveitis. The evaluation and the management of IOP are very important in treatment patients with uveitis, in addition to the management of intraocular inflammation.

Female↗

[Nonperforating trabecular surgery with reticulated hyaluronic acid implant].

OBJECTIVE: To evaluate the clinical results of nonperforating trabecular surgery (NPTS) with reticulated hyaluronic acid implant. METHODS: Twenty cases (28 eyes) of advanced open angle glaucoma (C/D = 0.86 +/- 0.14) underwent NPTS with reticulated hyaluronic acid implant. Postoperatively, the intraocular pressure (IOP), intraocular reactions and the bleb appearance were recorded, gonioscopy and ultrasound biomicroscopy were performed. RESULTS: The mean follow-up was (9.2 +/- 3.4) months. The mean IOP was (28.1 +/- 10.2) mm Hg preoperatively and (17.5 +/- 4.1) mm Hg postoperatively, the difference being significant (t = 5.776, P < 0.001). The number of drugs used for anti-glaucoma was (2.04 +/- 0.74) preoperatively, and (0.71 +/- 0.71) postoperatively (t = 8.103, P < 0.001). On the last visit, in 27 eyes (96.4%) the IOP was < or = 21 mm Hg, and among them, there were 12 eyes (42.8%) without anti-glaucoma medicine and 15 eyes with anti-glaucoma medicine. In 13 eyes (46.4%) the IOP was decreased > or = 10 mm Hg in which 6 eyes did not take any anti-glaucoma medicine and 7 eyes used anti-glaucoma medicine. There were no flare and cells in the anterior chamber in 14 eyes. In 10 eyes there was only slight flare that disappeared in 2-6 days. In 4 eyes there was a small amount of hyphema that was absorbed in 3-7 days. After operation, there was an obvious diffuse bleb in each eye, at the last visit, there were functional blebs in 19 eyes, the successful filtration was ceased in 9 eyes within 1.5-3 months. Intra-operatively, in 5 eyes microperforations occurred in the trabecular meshwork without iris prolapse, and after operation, under the gonioscope, the perforation could be observed in 3 eyes. In another 4 eyes, there was no intra-operative perforation, but a small fissure was seen by gonioscopy. In the post-operative 1-8 months, ultrasound biomicroscopy was performed, and it was shown that the implant was not degraded. CONCLUSIONS: The elevated IOP in patients with open angle glaucoma can be effectively reduced by NPTS, and the number of drugs used for anti-glaucoma was decreased. The post-operative complications were much less because of no intra-operative penetration of the anterior chamber. Therefore, NPTS is a very hopeful and practicable new anti-glaucoma surgery.

Adult↗

[To screen, clone and sequence TIGR gene mutation in Chinese patients with primary open- angle glaucoma].

OBJECTIVE: To study trabecular meshwork induced glucocorticoid response protein (TIGR) gene mutation in Chinese patients with primary open-angle glaucoma (POAG). METHODS: (1) From 70 patients with POAG and 20 normal controls, TIGR gene which consists of three exons (7 pairs of primer) was amplified by polymerase chain reaction (PCR). The mutation of PCR amplification products was evaluated by single-stranded conformation polymorphism (SSCP). (2) After the above PCR products were cloned into the PT-Adv vectors, the construction plasmids were evaluated by Ecor I endonuclease and direct sequence was performed. RESULTS: (1) With SSCP screening, the single strand band abnormality was found in the middle fragments of the third exon (the sixth pair of primer) of TIGR gene in two patients with POAG, but the control group appeared normal. (2) The two samples using clone and sequence showed that one had a 'GAT'- to- 'AAT' transition at amino acid Asp 338 Asn mutation; the base sequence of another one had no change. These results suggested that mutation rate of TIGR gene in Chinese patients with POAG be only 1.4% (1/70), being lower than that of foreigners. CONCLUSION: The pathogenesis of Chinese patients with POAG may be related with TIGR gene mutation, but the mutation rate is lower than that in foreigners, indicating that the mechanism of POAG in China and aboard is different and the pathogenesis of POAG has difference in regions and races.

Adolescent↗

[Reversed trabeculectomy for treatment of glaucoma].

OBJECTIVE: To reduce the postoperative blocking of the filtration canal in routine trabeculectomy with modification. METHODS: The modification of the procedure of routine trabeculectomy was that one end of the 4.0 mm x 1.5 mm deep layer scleral tissue including part of trabecular meshwork was not cut. Instead, the free end of the strip of deep scleral tissue was vertically rotated and sutured on the deep layer of the scleral bed posterior to it. The projection of the strip was utilized to prevent postoperative blocking of filtration canal. RESULTS: The mean period of postoperative follow-up was 23.5 months (range, 12 -- 36 months). In the treatment group (38 eyes of 33 cases), the intraocular pressure (IOP) was lowered from preoperative (25.41 plus minus 2.41) mm Hg to postoperative (14.74 plus minus 0.90) mm Hg. The IOP was lowered from preoperative (24.96 plus minus 1.35) mm Hg to postoperative (19.40 plus minus 1.43) mm Hg in the control group (40 eyes of 33 cases). The success rates were 94.7% and 77.5% in the treatment and control group respectively. CONCLUSIONS: The modified trabeculectomy is safe, easy to perform, and can effectively relieve the postoperative blocking of the filtration canal, control postoperative IOP and reduce postoperative recurrence.

Adult↗

Characterization of nitrergic neurons in the porcine and human ciliary nerves.

PURPOSE: To further characterize a subpopulation of choroidal ganglion cells associated with the ciliary nerves. METHODS: Isolated long ciliary nerves of porcine and human eyes containing ciliary nerve-associated ganglion cells (CNGCs) were embedded in Epon for ultrastructural investigation, or wholemounts were stained with antibodies against nitric oxide synthase (NOS), vasoactive intestinal polypeptide (VIP), vesicular acetylcholine transporter, neuropeptide Y (NPY), tyrosine hydroxylase (TH), calcitonin gene-related peptide (CGRP), substance P (SP), and synaptophysin. In addition, wholemount preparations of the choroid and of the anterior segment were stained for reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-D). Serial sections through choroid and anterior segment were stained with the prior antibodies listed. RESULTS: In the porcine choroid only CNGCs were present. They stained for brain (b)NOS and VIP and were surrounded by SP and VIP-immunoreactive (IR) nerve terminals. The axonal processes of the CNGCs followed the ciliary nerves to the anterior eye segment, where they formed a nerve fiber plexus that terminated in the trabecular meshwork. None of the axons passed into the sparse NOS-IR nerve fiber plexus surrounding the choroidal vasculature. The CNGCs in the human choroid morphologically resembled those seen in the pig. CONCLUSIONS: The CNGC proportion of choroidal ganglion cells is presumably involved in the intrinsic (peripheral) innervation of the aqueous outflow tissues and of the choroid.

Adult↗

Computational evaluation of the role of accommodation in pigmentary glaucoma.

PURPOSE: Accommodation has been proposed as the cause of the bowing of the posterior iris that occurs in eyes with pigmentary dispersion syndrome. A mathematical model of the anterior eye is needed to explore the elastohydrodynamic effects of accommodation on both the aqueous humor dynamics and the contour of the iris. METHODS: A mathematical model of the coupled aqueous humor-iris system was used to predict the effects of accommodation on the iris position and pressure distribution in the aqueous humor. RESULTS: The mathematical model predicts that accommodation produces a pressure reversal--the anterior chamber pressure being higher than the posterior chamber--and iris movement into a more concave configuration. Total time for accommodation, iris modulus, iris attachment point, and trabecular meshwork permeability all had little or no effect on the iris contour and pressure change. The amount of accommodation, however, had a dramatic effect on both the amount of iris curvature and especially the pressure reversal. For accommodation resulting in a 0.6-mm change in anterior chamber depth, the pressure in the anterior chamber was more than 1.0 mm Hg higher than that in the posterior chamber, compared with a pressure difference of less than 0.1 mm Hg for accommodation resulting in a 0.2-mm change in anterior chamber depth. CONCLUSIONS: The results confirm that accommodation produces bowing of the posterior iris and the magnitude of the bowing is a strong function of the amount of accommodation.

Accommodation, Ocular↗

[Intraocular pressure asymmetry and related factors in pseudoexfoliative syndrome].

PURPOSE: To determine the intraocular pressure (IOP) asymmetry in pseudoexfoliative (PSX) syndrome and glaucoma patients. To analyze the association between IOP asymmetry and clinical signs. METHODS: 191 patients were prospectively studied, 75 (39.3%) with PSX syndrome and 116 (60.7%) with PSX glaucoma. IOP, visual field test, pigment and PSX material deposit in anterior segment structures were observed and compared between both eyes. The relation between IOP and clinical sign asymmetry was analyzed. RESULTS: IOP asymmetry was less than 10 mm Hg in 138 cases (72.25%) and more than 10 mm Hg in 53 (27.75%) cases. The greatest asymmetry was found in unilateral PSX glaucoma patients (p= 0.001). Visual field test asymmetry was related with IOP asymmetry (p=0.0001). Also, IOP asymmetry was associated with pigment deposit in trabecular meshwork, in Sampaolesi line, and with pupillary atrophy asymmetry (p<0.05). PSX material deposit was not related with IOP asymmetry. CONCLUSIONS: IOP asymmetry is greater in unilateral PSX glaucoma patients. The association between IOP and visual field test asymmetry found in this study suggests that PSX glaucoma is pressure dependent. IOP seems to be related with pigment deposit in anterior segment structures in PSX patients. However, this association was not found with PSX material deposit.

Age Factors↗

[Histological examination on disks obtained by goniotrephining with scleral flap (author's transl)].

Histological examination with serial sections of 26 disks obtained by goniotrephining with scleral flap showed in three cases only lamellas and Descemet's membrane. Twenty-three disks contained trabecular meshwork, fourteen of these Schlemm's canal. In three disks excision reaches as far as the ciliary muscle. In three of the twenty-six eyes the intra-ocular pressure was not regulated after the operation. It seems that in goniotrephining with scleral flap the opening of Schlemm's canal has no important influence on the postoperative regulation of the final intra-ocular pressure.

Aged↗

[Isolated non-compaction of left ventricle in childhood: clinical experience with 5 cases].

BACKGROUND: Isolated noncompaction of the left ventricular myocardium, a rare congenital disorder, is thought to be due to an arrest of myocardial morphogenesis. It is characterized by an excessively prominent trabecular meshwork and by deep intertrabecular recesses. The aim of this study was to clarify the late outcome of this malformation, reporting our experience on 5 pediatric patients observed for a period of 11 years. METHODS: We describe the clinical, electrocardiographic and echocardiographic findings of 5 pediatric cases, with an age ranging from 1 month to 10 years. The mean follow-up was 4.5 years (> 10 years in 1 patient). RESULTS: In no case did life-threatening ventricular arrhythmias or systemic embolic events occur. Four patients who developed heart failure have been submitted to digoxin, diuretic, angiotensin-converting enzyme and anticoagulant therapy. One of them is still asymptomatic and in good health. One patient died while on the waiting list for cardiac transplantation. CONCLUSIONS: The appropriate and early diagnosis and treatment of this disorder can improve the outcome even though further studies will be needed to elucidate its long-term prognosis. At the same time, in view of the high incidence of a positive family history, evaluation of all members of the family is warranted.

Child↗

Coats' disease: A study of cholesterol transport in the eye.

An attempt to establish an animal model (rabbit) to study deposition and transport of cholesterol in the eye has been described. Interesting findings include the deposition of cholesterol in the choroid, sclera, and anterior cornea of rabbits fed on a high cholesterol diet. Injected intravitreal cholesterol is seen to leave through the retina, optic nerve head, and the trabecular meshwork. This process appears to be very slow. During the 4 months of observation the yellow preretinal deposits decreased little in size. Only 1 rabbit showed a picture typical of Coats' disease with serous detachment of the retina, subretinal lipoidal deposits and preretinal neovascularization. Although these results are preliminary, they suggest that fatty materials may pass through the retina into the subretinal space from the vitreous and might explain the pathogenesis of Coats' disease in the human.

Animals↗

[Steroid induced glaucoma].

Steroid treatment has gained notoriety due to its tendency to induce multiple side effects, including a variety of ocular side effects. Administration of local, regional, inhalation or systemic steroids may induce the development of ocular hypertension, which might even result in subsequent open angle glaucoma. About one in every three people is considered a potential "steroid responder". A significant elevation of intraocular pressure might result in these patients in response to steroid treatment. Included in this group are patients with first degree relatives suffering from open angle glaucoma. Morphologic changes in the trabecular meshwork (which serves as the site of aqueous humor drainage from the eye) are suggested as the proposed mechanism through which steroid treatment results in glaucoma. Steroids are said to induce the expression of a gene that is located on chromosome 1 and is known as TIGR or GLCIA. its product is a protein called myocilin. Ocular hypertension secondary to steroid treatment is usually reversible, when treatment is limited to a period of less than 12 months. The fear of ocular hypertension, which is usually unnoticed by the patient, obligates regular ophthalmologic follow-up examinations, including tonometry, visual fields and optic disc examinations.

Chromosome Mapping↗

[Non-penetrating trabecular surgery with application of mitomycin C].

OBJECTIVE: To evaluate the clinical effect of non-penetrating trabecular surgery (NPTS) with mitomycin C (MMC) in primary open-angle glaucoma (POAG). METHODS: Twenty-five eyes of 18 patients with POAG underwent NPTS with MMC during the operation. The mean follow-up was 16.6 months (6 - 28 months). RESULTS: The mean preoperative intraocular pressure (IOP) was (27.93 +/- 7.62) mm Hg (1 mm Hg = 0.133 kPa) which decreased to a mean postoperative IOP of (14.62 +/- 3.53) mm Hg (P < 0.001). After operation, there was an obvious diffuse bleb in each eye, in the 3 months after operation, there were functional blebs in 21 eyes, and the successful filtration was ceased in 4 eyes. The anterior chamber reaction was mild. Hyphema occurred in 1 eye after operation. Intra-operatively, in 4 eyes microperforations occurred in the trabecular meshwork without iris prolapse, and after operation, under the gonioscope, the perforation could be observed in these eyes. In another 2 eyes, there was no intra-operative perforation, but a small fissure was seen by gonioscopy. CONCLUSIONS: NPTS with application of MMC can lower the IOP effectively in this group of patients. The recovery of vision after operation is quick. A few complications occurred after operation. It is a promising technique to treat POAG.

Adolescent↗

[Physiology of aqueous humor outflow resistance: its relation to giant vacuoles].

About 2% of the French population over the age of 40 suffers from open angle glaucoma, a disorder for which ocular hypertension is the main risk factor. Improving our understanding of primary open-angle glaucoma physiopathology has been an area of intense research for nearly a century. The main aqueous outflow system in the human eye includes the trabecular meshwork, Schlemm's canal, aqueous veins, and the episcleral veins. Schlemm's canal is bordered by endothelium cells, many of which contain giant vacuoles, structures that are sensitive to intraocular pressure and that therefore can act as markers of active outflow. Giant vacuoles are most often found near collector channels in normal eyes, probably in areas of low downstream pressure. In the glaucoma eye, determining where giant vacuoles form could help localize the site of pathological outflow resistance.

Aqueous Humor↗

DNA damage and alterations of gene expression in chronic-degenerative diseases.

Chronic-degenerative diseases (CDD) recognise a variety of exogenous and endogenous risk factors interacting with the organism for many years before disease onset. We applied genomic and postgenomic molecular analyses in experimental models characterised by different contribution of exogenous and endogenous CDD risk factors. Exposure of mice to halogen light for 28 days resulted in induction of cyclobutane dimers and oxidative DNA damage in the skin. Evaluation of postgenomic alterations by cDNA arrays revealed upregulation of DNA repair pathways, increased cell division rate and protooncogenes transcription, resulting in skin tumors, 1 year later. Exposure of p53-/+ mutant mice to cigarette smoke (CS) for 28 days induced DNA adducts formation in the lung. Postgenomic alterations included decreased apoptosis and increased cell division, as compared to CS-exposed wild type mice. These phenomena resulted in lung tumors, 9 months later. Transplacental exposure of mouse foetuses to cigarette smoke induced DNA adduct formation in the liver. cDNA arrays analyses demonstrated decreased cell division, apoptosis increase, and tissue hypoxia. These phenomena resulted in growth retardation of the whole organism. Molecular alterations were investigated in human trabecular meshwork, the non-replicating ocular epithelia involved in the pathogenesis of chronic degenerative glaucoma. Results indicate increased oxidative DNA damage in glaucoma patients as compared to unaffected controls. These four experimental studies suggest that DNA damage may result in different CDD (cancer, growth retardation, glaucoma) depending on the replication rate of the target cell population.

Animals↗