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Intermittent disturbances are common in ECG signals recorded with smart clothing: this is mainly because of displacement of the electrodes over the skin. We evaluated a novel adaptive method for spatio-temporal filtering for heartbeat detection in noisy multi-channel ECGs including short signal interruptions in single channels. Using multi-channel database recordings (12-channel ECGs from 10 healthy subjects), the results showed that multi-channel spatio-temporal filtering outperformed regular independent component analysis. We also recorded seven channels of ECG using a T-shirt with textile electrodes. Ten healthy subjects performed different sequences during a 10-min recording: resting, standing, flexing breast muscles, walking and pushups. Using adaptive multi-channel filtering, the sensitivity and precision was above 97% in nine subjects. Adaptive multi-channel spatio-temporal filtering can be used to detect heartbeats in ECGs with high noise levels. One application is heartbeat detection in noisy ECG recordings obtained by integrated textile electrodes in smart clothing.

Unlabelled: PEDF (pigment-epithelium-derived factor) is a member of the serpin family of protease inhibitors. It is considered to be an important regulator of human eye disease and is known to inhibit angiogenesis. We have therefore investigated the presence of PEDF in the subretinal fluid of patients with retinal detachment., Methods: Eighteen samples from SRF were collected from patients during retinal detachment surgery. Specific ELISA analysis was performed with specific IgG against human PEDF., Results: PEDF was detected in the subretinal fluid of all cases. The mean concentration of PEDF was 33.9 ng/ml (SD 23.7 ng/ml; range 5.3-74.7 ng/ml). The majority of samples had however a concentration of more than 22 ng PEDF/ml fluid., Conclusion: PEDF appears to be a constant component of the fluid accumulating in the subretinal space after retinal detachment. The known effects of PEDF, however, suggest that it may be involved in physiological processes of wound healing in the subretinal space., (Copyright (c) 2006 S. Karger AG, Basel.)

Purpose: To evaluate the role of pars plana vitrectomy-assisted incisional biopsies in the management of choroidal tumors of unclear origin., Design: Retrospective, noncomparative, consecutive interventional case series., Methods: Ten consecutive patients with indeterminate choroidal tumors underwent a standardized three-port pars-plana vitrectomy-assisted subretinal biopsy using a bimanual approach with standard intraocular forceps and a diamond knife. Specimens were fixed in formaldehyde embedded in paraffin and further subjected to histopathological and immunohistochemical analyses., Results: A histologic diagnosis was obtained in all (10 of 10) cases including choroidal melanoma (five of 10), metastasis (two of 10), subretinal hemorrhage (two of 10), and nodular scleritis (one of 10). Five eyes were enucleated as a result of the histologic diagnosis. Three cases of postoperative complications were seen in three patients (newly formed rhegmatogenous retinal detachment, increased serous retinal detachment, and vitreous hemorrhage). No cases of intra- or extraocular tumor spread were detected through follow-up periods ranging from 3 to 29 months., Conclusions: Pars plana vitrectomy-assisted incisional biopsy is a valuable diagnostic procedure for cases of choroidal tumors of unknown origin in selected patients. However, the relatively high frequency of postoperative complications noted in the present study and the potential risk of dissemination of tumor cells underscores the importance of rigorous case selection.

Unlabelled: Connective tissue growth factor (CTGF) has been shown to be substantially involved in various processes of fibrosis. Herein we report on the presence of CTGF in the subretinal fluid (SRF) of patients with retinal detachment., Methods: Samples of SRF were collected from 10 patients during retinal detachment surgery. Specific ELISA analysis was performed with goat IgG against human CTGF., Results: CTGF was above the detection limit of the assay in all samples. On average the concentration of CTGF in SRF was 10 ng/ml (SD 3.7, range 3.7-15.7 ng/ml). There was an increase in the CTGF concentration with time between the diagnosis of retinal detachment and surgery (correlation r = 0.67)., Conclusion: CTGF appears to be a constant component of the fluid accumulating in the subretinal space after retinal detachment. The origin of subretinal CTGF and its physiological importance is still unclear. The known effects of CTGF, however, suggest that it may be involved in both the physiological processes of wound healing in the subretinal space and also in the pathological events such as subretinal fibrosis. The observed increase in CTGF concentration with time suggest that CTGF plays a role in the pathophysiology of subretinal scarring in cases of delayed retinal surgery., (Copyright (c) 2005 S. Karger AG, Basel.)

Purpose: Transpupillary thermotherapy (TTT) is currently being evaluated for treatment of choroidal neovascularization (CNV) in age-related macular degeneration. To optimize TTT for CNV, the effect was analyzed of invisible (subthreshold) or visible (threshold) doses of TTT on the normal mouse retina and on experimental CNV., Methods: TTT was delivered to the normal retina of 42 mice with a diode laser at increasing power settings (50, 60, 70, or 80 mW), to obtain thermal lesions ranging from invisible (subthreshold) to visible (threshold) burns. CNV was induced in 53 mice by krypton laser photocoagulation of the fundus, after which the CNV lesions were treated with TTT (50, 60, or 80 mW). Eyes were enucleated 7 days after TTT and prepared for histology, and the CNV complex was evaluated on hematoxylin-eosin stained serial sections by measuring the maximum height of the CNV lesions. Ultrastructural changes were examined by transmission electron microscopy., Results: Increasing the TTT laser power yielded gradually more visible effects. At 50 mW, which induced subthreshold burns, no damage was seen in the neural retina, retinal pigment epithelium (RPE), or choroid at any time point. By contrast, eyes treated with higher power exhibited progressively more damage to the neural retina, including a complete disruption of the outer nuclear layer. When TTT was applied to the laser-induced CNV lesions, the height of lesions was significantly reduced (P < 0.001) in response to all three power settings at 7 days after treatment. The mean relative thickness of the CNV lesion was 3.29 +/- 0.89 in untreated mice, whereas in TTT-treated mice it was 1.69 +/- 0.35, 1.69 +/- 0.41 and 1.70 +/- 0.17 at power settings of 50, 60, and 80 mW, respectively. The overlying neural retina showed no apparent damage with the 50- or 60-mW settings, whereas outer nuclear layer disruption occurred with a power of 80 mW. Electron microscopy confirmed the presence of vascular occlusion at 1 day and a fibrotic scar at 7 days after TTT., Conclusions: Subthreshold TTT can effectively occlude newly formed vessels and cause regression of the experimental CNV complex without damaging the neural retina. The results demonstrate the importance of using subthreshold laser power in experimental and clinical evaluation of TTT.

Purpose: Findings in studies have suggested a role for matrix metalloproteinase (MMP)-2 in angiogenesis, including choroidal neovascularization (CNV). To investigate further, the current study was conducted to observe the formation of experimental CNV in MMP-2-deficient mice., Methods: CNV was induced in wild-type and MMP-2-deficient mice by krypton laser photocoagulation of the fundus. The time-course of expression of MMP-2 mRNA after laser treatment was determined by in situ hybridization with anti-sense and sense cRNA probes. MMP-2 protein distribution was determined by immunohistochemistry. Ten days after treatment, the extent of CNV was evaluated on hematoxylin-eosin stained serial sections. The maximum height of the CNV lesions was calculated by image analysis of digitized histologic images., Results: Expression of MMP-2 mRNA was detected in the CNV lesions at day 3 after laser treatment and peaked at day 5, after which it slowly declined. MMP-2 mRNA expression appeared to be highest at the margins of the membrane. Immunostaining for MMP-2 confirmed the presence of MMP-2 protein in the CNV lesions. The CNV lesions of MMP-2-deficient mice showed that relative thickness was reduced by 31% compared with wild-type mice (P = 0.006)., Conclusions: The present study demonstrated that MMP-2 mRNA and protein are upregulated during experimental CNV in the mouse. The marked difference in thickness of the CNV membrane between wild-type and MMP-2-deficient mice shows that MMP-2 is involved in the formation of experimental CNV in the mouse. These results suggest that pharmacologic targeting of MMPs, including MMP-2, may reduce formation of CNV in conditions such as age-related macular degeneration.

Purpose: Matrix metalloproteinases (MMP) are a family of extracellular matrix degrading enzymes associated with the development of neovascularization. To investigate the possible role of these enzymes in choroidal neovascularization, the mRNA expression of MMPs and tissue inhibitors of metalloproteinases (TIMPs) were analyzed in subfoveal fibrovascular membranes from patients with age-related macular degeneration (AMD)., Methods: Surgically removed subfoveal fibrovascular membranes from five eyes were analyzed for the expression of MMP and TIMP mRNA. In situ hybridization anti-sense and sense riboprobes were generated using DNA complementary to human collagenase (MMP-1), 72 kDa gelatinase (MMP-2), stromelysin (MMP-3), 92-kDa gelatinase (MMP-9), TIMP-1, TIMP-2, and TIMP-3. Vascular endothelial cells were detected using immunostaining for von Willebrand factor., Results: MMP-2 and MMP-9 mRNA were detected in all specimens. Most of the membranes also expressed TIMP-1 and TIMP-3 mRNA, and two of the membranes expressed TIMP-2 mRNA. MMP-2, TIMP-1, and TIMP-2 mRNA had a similar overall distribution that was relatively uniform within the vascularized membrane stroma. MMP-2 expression appeared to be localized mainly to the vascular endothelial cells, whereas TIMP-1 and TIMP-3 were detected in other cell types such as fibroblastlike cells. MMP-9 expression was distinctly expressed by cells at the margins of the membranes and often in proximity to a thickened Bruch's membrane-like layer under the retinal pigment epithelial cells. TIMP-3 mRNA was strongly expressed within the retinal pigment epithelial cell layer and also in the stroma of one membrane. None of the membranes showed detectable MMP-1 or MMP-3 expression., Conclusions: The results support a role for MMPs in the development of choroidal neovascularization in AMD. The localization of MMP-2 and MMP-9 to the areas of new vessel formation and to the enveloping Bruch's-like membrane, respectively, suggests that MMP-2 and MMP-9 may be cooperatively involved in the progressive growth of choroidal neovascular membranes in AMD.

Background: Data are scarce on the actual rate and mode of outer nuclear layer decay in retinal detachment (RD). We used an experimental rabbit model to assess the presence of apoptosis and rate of photoreceptor death following RD. This model included the creation of localized and stable retinal blebs, while controlling for any decline of retinal elevation over time., Methods: RD was produced in New Zealand white rabbits by injecting 0.05 ml of 15% sodium hyaluronate (Healon GV) under the neural retina using a microsurgical technique. Animals were killed at 1, 2, 4, 7, 14 and 29 days. Retinal tissue was processed for light and electron microscopy and for in situ end labeling of fragmented DNA using a modification of the TUNEL technique. Photoreceptor cell nuclei were counted in the RD areas of maximum retinal elevation of 28 eyes, and an additional 4 eyes were used for nick end labeling., Results: Positive DNA nick end labeling, ultrastructural features and absence of necrotic cells indicated apoptotic photoreceptor cell death. Also, there was a rapid, almost linear elimination of photoreceptor nuclei over time. At 14 days only half of the number of nuclei were discernible, while approximately one tenth remained after 29 days. There was a statistically significant, but minimal decline in RD height over the 4 weeks of study., Conclusion: Following experimental RD in rabbits, apoptotic cell death is associated with an almost linear elimination of photoreceptor cells over time. The use of highly viscous sodium hyaluronate in separating the neural retina from the retinal pigment epithelium allows the RD to maintain a nearly constant height over a period of 4 weeks.

Unlabelled: A study was carried out to investigate whether human RPE allografts are tolerated or rejected in the subretinal space and to determine the feasibility of RPE transplantation in subjects with age-related macular degeneration (AMD)., Methods: Patches of human fetal RPE (13-20 weeks of gestational age) were transplanted into the subretinal space of five patients after surgical removal of subfoveal fibrovascular membranes, and to four subjects with dry geographic atrophy. Suspensions of RPE cells were transplanted to four other patients with nonexudative AMD. Results were evaluated with clinical ophthalmological examination, SLO microperimetry and fluorescein angiography over 8-20 months., Results: In disciform lesions, RPE transplants developed macular edema and fluorescein leakage concomitant with gradual reduction of visual acuity, implying host-graft rejection, over 1-6 months. In geographic atrophy, three of four transplants showed little change in shape and size after 12 months (one transplant was slowly rejected). In non-exudative AMD, RPE suspension transplants showed no evidence of rejection and were associated with the disappearance of drusen; visual acuity remained stable and SLO microperimetry confirmed retinal function over the transplanted area., Conclusion: Human RPE allografts are not invariably rejected in the subretinal space without immunosuppression. The rejection rate is lower in nonexudative than in neovascular AMD. An intact blood-retinal barrier is likely to protect against rejection. It is technically feasible to transplant human RPE into the submacular space without adversely affecting visual function in nonexudative AMD over relatively long periods of time.

Background: RPE transplantation offers the possibility of treating certain forms of retinal degeneration. Understanding how to optimize the surgical technique for performing RPE transplantation, especially in primates, is therefore of considerable interest., Methods: Fifteen patch RPE transplants were performed in six monkeys. The transplant sites were examined at follow-up by ophthalmoscopy, biomicroscopy, fluorescein angiography and histology. Foveal and peripheral retinal transplants were compared., Results: Human fetal RPE xenografts can survive without rejection for at least 6 months after transplantation in monkey retina. Such grafts form a basal lamina and make intimate contacts with the outer segments of the host. Both rods and cones retain a normal appearance when in contact with unrejected transplants. Rejection occurred in only 30% (3/10) of the peripheral but in 60% (3/5) of the foveal transplants., Conclusions: Cultured human fetal RPE patch transplants can survive and maintain local photoreceptor integrity for relatively long periods of time in monkey subretinal space without immunosuppression. Rejection, when it occurs, is more frequent near the fovea.

Purpose: Vascular endothelial growth factor (VEGF) is a potent and specific angiogenic growth factor, in vitro and in vivo, that may be associated with the development of intraocular neovascularization. In the current study, the authors analyze the expression of VEGF in subfoveal fibrovascular membranes from patients with age-related macular degeneration., Methods: Surgically removed subfoveal fibrovascular membranes from 18 eyes were analyzed for the expression of VEGF mRNA and protein using in situ hybridization and immunohistochemistry, respectively., Results: Most specimens expressed both VEGF mRNA and protein. The VEGF mRNA expression was particularly high in areas with a marked inflammatory response, in which the expression was concentrated to cells resembling fibroblasts and to surrounding inflammatory cells. VEGF protein expression was seen in fibrovascular parts of the membranes and was predominantly localized to the cytoplasm of fibroblastlike cells. In some of these membranes, strong VEGF protein immunoreactivity also was concentrated to extracellular matrix foci within the fibrovascular stroma., Conclusions: Results indicate that VEGF may be of pathogenetic importance for the development of the choroidal neovascularization (age-related macular degeneration) and also may implicate a role of fibroblasts of presumable choroidal origin in this process.

Background and Objective: To eliminate sharp needles when administering local anesthesia to the eye in order to reduce serious complications caused by needle perforation., Patients and Methods: After topical anesthesia, limbal conjunctival incision, and sub-Tenon's dissection, a retrobulbar irrigation of an equal mixture of bupivacaine (5 mg/ml) and lidocaine (20 mg/ml) was given using a blunt cannula., Results: The technique was used in both vitreoretinal surgery (n = 70) and anterior segment surgery (n = 235) with good analgesic and akinetic effects. No serious adverse were noted., Conclusion: This proved to be a safe and efficient technique that abandoned the use of sharp needles.

Background and Objective: To determine the ocular perforations during retrobulbar and peribulbar injections., Patients and Methods: Twenty-five ocular perforations between 1976 and 1993 occurred after 13 retrobulbar and 12 peribulbar injections. Eighteen patients (72%) were women. Eighteen eyes were myopic (72%). Risk factors included high myopia in 11 cases (44%), use of Atkinson gaze in 21 cases (84%) and a sharp injection needle., Results: Deep position of the posterior pole was common. Perforation signs comprised vitreous hemorrhage in 25 eyes (100%), subretinal hemorrhage in 19 eyes (76%), retinal breaks along the inferior vascular arcade in 19 eyes (76%), and retinal detachment in 14 eyes (56%). Proliferative vitreoretinopathy developed in 11 eyes (44%)., Conclusion: Retinal detachment strongly correlated to poor visual outcome.

Purpose: To transplant human fetal retinal pigment epithelium (RPE) into the subretinal space of rabbits and monkeys as an organized monolayer without artificial support., Methods: The method involves dissecting small patches of cultured RPE monolayers in sheets (1 to 5 mm2), sucking them into a glass pipette and injecting them into the subretinal space after producing a bleb detachment of the neural retina., Results: These patches unfold and survive as a quasi-monolayer under the reattached neural retina intimately associated with the host photoreceptors and phagocytizing host outer segment material. Graft rejection is observed in most rabbits at 1 month but not in monkeys at 3 months after transplantation., Conclusions: Monolayer patches of cultured human fetal RPE can be transplanted to the subretinal space, where they survive in contiguity with healthy host outer segments. In primates, but not in rabbits, host-graft rejection does not occur for at least 2 to 3 months.

Background: Age-related macular degeneration (ARMD) is caused by abnormal retinal pigment epithelium (RPE) and may be complicated by choroidal neovascularization. The object of treatment would be to replace the diseased RPE with normal human RPE., Method: Five patients with ARMD (preoperative visual acuity 0.08-0.2) underwent removal of subretinal fibrovascular membranes using pars plana vitrectomy techniques. Human fetal RPE (15-17 weeks gestational age) was cultured and transplanted as a monolayer patch into the subretinal space. Transplants were followed by funduscopy and fluorescein angiography. Macular function was assessed using scanning laser ophthalmoscopic (SLO) microperimetry., Results: Three RPE transplants were placed in the fovea; two were placed parafoveally. All transplants have survived for 3 months. They have grown and increased in size covering part of the epithelial defect caused by removal of the fibrovascular membrane. SLO microperimetry indicated that visual function was present in four of the transplants at 1 month but in only two at 3 months after surgery. Function over the transplants, especially those in the fovea, was compromised by cystoidlike macular edema., Conclusions: Human fetal RPE transplants survive well in the macula for as long as 3 months. They are capable of growing to cover epithelial defects caused by removal of subretinal neovascular membranes. The causes for development of macular edema in transplants directly in the fovea warrant further evaluation.

Eighteen patients with age-related macular degeneration developed subfoveal membranes that were surgically removed and submitted for histopathological examination. Immunohistochemical techniques were performed, using a panel of monoclonal antibodies recognizing retinal pigment epithelial (RPE) cells, myofibroblasts, pericytes, endothelial cells, glial cells, smooth muscle cells and various types of macrophages. The PC10 antibody to proliferating cell nuclear antigen (PCNA) was applied as a marker of proliferating cells. The specimens displayed a core of neovascular stroma surrounded by a rim of more fibrous tissue. All specimens contained abundant RPE cells that in some cases appeared to envelop part of the membrane. Most cases had basal laminar deposits and thickened basement membrane material adjacent to the RPE cells suggestive of parts of Bruch's membrane. Often this Bruchlike membrane appeared at the surgical margin, forming a surgical cleavage plane. Chronic inflammatory cells were abundant, but polymorphonuclear leukocytes were notably absent. Nearly all specimens contained myofibroblasts and various types of macrophages. The presence of myofibroblasts suggests subretinal membrane contraction, which may induce new breaks and other pathology in RPE layer and Bruch's membrane.

Perfluorocarbon liquids, including perfluorodecalin (PFD), are useful intraoperative tools in complicated vitreoretinal surgery, such as for giant retinal tears, PVR and intraocular foreign bodies. Due to its high specific gravity (1.91 g/cm3) subretinal complications of PFD may occur. The consequences of subretinal PFD were studied in 23 albino rabbits (28 eyes). Using glass micropipettes (outer diameter of tip 100-120 microns), we injected 50-100 microliters PFD subretinally via the vitreous space. The same volume of BSS was injected into 18 control eyes. Eyes were monitored by indirect ophthalmoscopy and examined by light and electron microscopy at 1, 2 and 3 days, and 1, 2, 4 and 12 weeks. Progressive retinal detachments with newly formed retinal breaks in the inferior quadrants developed in 26 of 28 eyes. As early as 1 day postoperatively, subretinal PFD induced loss of outer and inner segments. Local retinal necrosis occurred in 4 eyes 5-7 days after surgery. A marked vacuole formation in retinal layers and PFD emulsification were regularly seen. The control eyes healed spontaneously. Toxic, mechanical and barrier effects may have caused the retinal damage. We advocate that all PFD be removed from the eye at surgery.

Tinted sodium hyaluronate (Healon Yellow) was used during posterior segment surgery mainly for the dissection of epiretinal membranes in cases of proliferative diabetic retinopathy and macular pucker. The yellow color facilitated injecting the viscoelastic substance under the membranes and simplified its removal at the end of surgery.

Metal retinal tacks were used in 18 patients with complicated retinal detachments, such as giant tears (3 cases), severe proliferative vitreoretinopathy (PVR) (7 eyes) and diabetic traction and rhegmatogenous detachment (8 cases). All eyes had undergone vitreous microsurgery, including excision or segmentation of epiretinal membranes, fluid-air (SF6) or silicone oil exchange. Retinal breaks and the cut edges of retinotomies and retinectomies were successfully sealed by metal tacks. Retinal re-attachment was achieved in 9 cases and partial re-attachment in another 5 eyes (follow-up 3-6 months). Retinal tears in diabetic macular detachment associated with extensive epiretinal fibrovascular membranes were also successfully sealed despite persisting traction. Our first experience indicates that the closing of retinal breaks with metal tacks is a major step forward in retinal re-attachment surgery.

Expanded patches of polytetrafluoroetylen, teflon (Impra) together with a tissue adhesive (cyanoacrylate) have been used to reinforce the scleral wall. The material has been used in 3 different trials on animals in periods up to 8 months. The histological analysis showed that the material was well accepted. The study indicates that scleral reinforcement with teflon and cyanoacrylate is a safe procedure.

In eyes with retinal detachment and a horseshoe break, vitreous traction on the retina has been relieved by severing the flap of the break with the aid of the Q-switched Nd:YAG laser. The retina often flattens in eyes with shallow retinal detachment after this treatment; the breaks then can be sealed off with argon laser. In cases of retinal detachment treated with expanding gas, fewer recurrences were observed when vitreous traction had been relieved by Nd:YAG laser treatment.