Distribution and activity of the anaerobic methanotrophic community in a nitrogen-fertilized Italian paddy soil

In order to mitigate methane emissions from paddy fields, it is important to understand the sources and sinks. Most paddy fields are heavily fertilized with nitrite and nitrate, which can be used as electron acceptors by anaerobic methanotrophs. Here we show that slurry incubations of Italian paddy field soil with nitrate and ¹³C-labelled methane have the potential for nitrate-dependent anaerobic oxidation of methane (79.9 nmol g^-1_dw d^-1). Community analysis based on 16S rRNA amplicon sequencing and qPCR of the water-logged soil and the rhizosphere showed that anaerobic oxidation of methane-associated archaea (AAA), including Methanoperedens nitroreducens, comprised 9% (bulk soil) and 1% (rhizosphere) of all archaeal reads. The NC10 phylum bacteria made up less than 1% of all bacterial sequences. The phylogenetic analysis was complemented by qPCR showing that AAA ranged from 0.28 × 10⁶ to 3.9 × 10⁶ 16S rRNA gene copies g^-1_dw in bulk soil and 0.27 × 10⁶ to 2.8 × 10⁶ in the rhizosphere. The abundance of NC10 phylum bacteria was an order of magnitude lower. Revisiting published diversity studies, we found that AAA have been detected, but not linked to methane oxidation, in several paddy fields. Our data suggest an important role of AAA in methane cycling in paddy fields.

Endogenous myoglobin in human breast cancer is a hallmark of luminal cancer phenotype

Background:

We aimed to clarify the incidence and the clinicopathological value of non-muscle myoglobin (Mb) in a large cohort of non-invasive and invasive breast cancer cases.

Methods:

Matched pairs of breast tissues from 10 patients plus 17 breast cell lines were screened by quantitative PCR for Mb mRNA. In addition, 917 invasive and 155 non-invasive breast cancer cases were analysed by immunohistochemistry for Mb expression and correlated to clinicopathological parameters and basal molecular characteristics including oestrogen receptor-α (ERα)/progesteron receptor (PR)/HER2, fatty acid synthase (FASN), hypoxia-inducible factor-1α (HIF-1α), HIF-2α, glucose transporter 1 (GLUT1) and carbonic anhydrase IX (CAIX). The spatial relationship of Mb and ERα or FASN was followed up by double immunofluorescence. Finally, the effects of estradiol treatment and FASN inhibition on Mb expression in breast cancer cells were analysed.

Results:

Myoglobin mRNA was found in a subset of breast cancer cell lines; in microdissected tumours Mb transcript was markedly upregulated. In all, 71% of tumours displayed Mb protein expression in significant correlation with a positive hormone receptor status and better prognosis. In silico data mining confirmed higher Mb levels in luminal-type breast cancer. Myoglobin was also correlated to FASN, HIF-2α and CAIX, but not to HIF-1α or GLUT1, suggesting hypoxia to participate in its regulation. Double immunofluorescence showed a cellular co-expression of ERα or FASN and Mb. In addition, Mb levels were modulated on estradiol treatment and FASN inhibition in a cell model.

Conclusion:

We conclude that in breast cancer, Mb is co-expressed with ERα and co-regulated by oestrogen signalling and can be considered a hallmark of luminal breast cancer phenotype. This and its possible new role in fatty acid metabolism may have fundamental implications for our understanding of Mb in solid tumours.

The effects of ranibizumab (Lucentis) on retinal function in isolated perfused vertebrate retina

BACKGROUND

Intraocular ranibizumab (Lucentis, Novartis, Basel Switzerland) is the primary choice in the treatment of neovascular age-related macular degeneration (AMD). Vascular endothelial growth factor (VEGF) is known to be a survival factor for neuronal cells. Therefore, blockage of all VEGF isoforms by ranibizumab could induce retinal dysfunction.

METHODS

Using isolated bovine retinas, the electroretinogram (ERG) was recorded as a transretinal potential using Ag/AgCl electrodes, while the retinas were perfused with an oxygen preincubated nutrient solution. For 45 min, ranibizumab was applied at a concentration of 0.2 mg/ml and alternatively the solvent carrier without the active agent. The ERG was monitored before, during and after exposure.

RESULTS

The concentration of 0.2 mg/ml ranibizumab induced a non-significant b-wave reduction of 22.32% after exposure (p = 0.13). For the a-wave amplitude only a reduction of 4% was detected (p = 0.18). The solvent carrier induced no significant reduction of the a- and b-wave amplitudes (p = 0.30 and p = 0.979, respectively).

CONCLUSION

In the ex vivo model, the isolated perfused vertebrate retina, ranibizumab has been proven to be a safe compound at the concentrations applied. The stability of the ERG-amplitudes rules out a considerable retinal dysfunction after an injection of up to 1 mg ranibizumab.

[High-dose intravenous immunoglobulins for treatment of optic neuritis in Guillain-Barré syndrome]

BACKGROUND

Guillain-Barré syndrome (GBS) is an acute inflammatory demyelinating disease of the peripheral nervous system. Treatment strategies include systemic steroids, immune adsorption, plasmapheresis, and intravenous immunoglobulins. Optic neuritis as an affectation of the central nervous system does not belong to the normal spectrum of neurological symptoms in GBS, which is thought to be restricted to the peripheral nervous system.

CASE REPORT

A 55-year-old female patient with unilateral optic neuritis secondary to GBS was referred to our department. Visual acuity was 0.04 in the affected left eye, L. E. and 1.25 in the right eye, R. E. Visual field testing revealed a large centrocecal scotoma. Ophthalmoscopy disclosed a slight oedema of the left optic disc. High-dose steroid treatment based on the diagnosis of optic neuritis secondary to GBS could not improve vision in the patient's left eye. Therefore, a repetitive treatment with high-dose intravenous immunoglobulins (IVIg) was initiated. The patient underwent three treatment cycles - 0.4 g per kg daily for 5 days - with intervals of two weeks between each cycle. Visual acuity and visual field improved gradually after the initiation of the immunoglobulin treatment. At the end of the last treatment course - 7 weeks after the begin of ocular symptoms - visual acuity had recovered to 0.8. A small residual paracentral scotoma resolved completely within the following weeks. Further follow-up examinations revealed a complete recovery of visual acuity to 1.0. Side effects of the immunoglobulin treatment were not observed throughout the treatment period.

CONCLUSIONS

Based on the observation that the clinical improvement in our patient coincided with the initiation of the IVIg treatment after steroid treatment had failed, we feel justified in drawing attention to IVIg as a potential treatment option in patients with GBS and involvement of the optic nerve.

[Changes of the triple flash electroretinogram after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in age-related macular degeneration]

BACKGROUND

The aim of the present study was to evaluate potential electrophysiological changes after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in patients with age-related macular degeneration.

METHODS

A consecutive series of 32 patients suffering from subfoveal choroidal neovascularisation secondary to age-related macular degeneration underwent 360 degrees retinotomy and macular translocation. The scotopic triple-flash ERG (TERG) served as the main parameter of the study and was recorded one day prior to the translocation surgery and no earlier than 4 weeks after the silicone oil removal.

RESULTS

The TERG amplitudes were significantly reduced after translocation surgery. Depending on the applied flash luminance the mean amplitude reduction of the first b-wave varied between 67 % (0.2 cds/m (2)) and 74 % (0.03 cds/m (2)). The latency of the second b-wave of the preoperative TERG proved to have predictive power with reference to the postoperative visual acuity. A statistically significant correlation between the latency of the second b-wave for a flash intensity of 0.03 and 0.1 cds/m (2) and the postoperative visual acuity was shown (p = 0,016 and p = 0,049).

CONCLUSIONS

In accordance with previous studies the present study indicates that a significant electrophysiological decrease is caused by surgical procedures associated with macular translocation. In future, due to predictive parameters of the TERG the preoperative selection of patients could be improved.

[Early postoperative spikes of the intraocular pressure (IOP) following phacoemulsification in late-stage glaucoma]

BACKGROUND

Modern cataract surgery with use of viscoelastics can induce remarkable early spikes of the intraocular pressure (IOP) in patients with glaucoma.

PATIENTS AND METHODS

The purpose of this prospective study was to investigate risk factors for an early increase of the IOP following cataract surgery in eyes with end-stage glaucoma. Clear cornea phacoemulsification with implantation of a foldable acrylic lens was performed in 25 eyes with end-stage glaucoma (primary open-angle glaucoma including normal tension glaucoma or exfoliative glaucoma) either under topical anesthesia or under general anesthesia. In eyes with exfoliative glaucoma, trabecular aspiration was performed additionally. IOP measurements were conducted at the day before surgery, 4 hours following surgery and on the first morning following surgery.

RESULTS

Cataract surgery was performed without complications. The mean IOP was 18.5 +/- 4.2 mm Hg with 2.1 +/- 1.0 topical medications. 4 hours postoperatively, mean IOP was 31.3 +/- 11.9 mm Hg. In eyes with exfoliative glaucoma (n = 12) the early postoperative IOP was 28.5 +/- 12.0 mm Hg, but without significant difference compared to eyes with POAG (n = 13). The early postoperative IOP showed significant correlation with the maximum IOP in patient's history (p = 0.014).

CONCLUSIONS

Patients with late-stage glaucoma can experience considerable early IOP spikes following uneventful cataract surgery, although preoperatively IOP is controlled by topical medications. Postoperative IOP monitoring is recommended at the day of surgery, especially if high IOP values are reported in patient's history.

Effects of bevacizumab on retinal function in isolated vertebrate retina

BACKGROUND

Bevacizumab (Avastin) is a recombinant protein that targets vascular endothelial growth factor (VEGF). In vitro, bevacizumab inhibits VEGF induced cell proliferation and tissue factor production. Abnormal angiogenesis involving VEGF is a central event during the development of choroidal neovascularisation (CNV). The present study was designed to evaluate the short term toxic effects of bevacizumab on retinal function for a therapeutic intraocular application.

METHODS

Isolated bovine retinas were perfused with an oxygen pre-incubated nutrient solution. The electroretinogram (ERG) was recorded as a transretinal potential using silver/silver chloride electrodes. Bevacizumab was added in different concentrations to the nutrient solution for 45 minutes. Thereafter the retina was reperfused for 60 minutes with normal nutrient solution. The percentage of a-wave and b-wave reduction during the application of bevacizumab was calculated and compared to control recordings.

RESULTS

During the application of three different concentrations of bevacizumab (0.08 mg/ml, 0.25 mg/ml, 0.8 mg/ml) no significant reduction of the a-wave and b-wave amplitude was observed. During the washout, the ERG amplitudes were unchanged.

CONCLUSION

The present study suggests that an intraocular application of 0.25 mg/ml bevacizumab for the treatment of CNV is reasonable. No significant short term effects of bevacizumab on retinal function were detected, but long term effects cannot be excluded.

Effects of patent blue on human retinal function

BACKGROUND

Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. Lately, the application of patent blue for staining of the internal limiting membrane has been proposed as an alternative to the standard procedures during macular hole surgery. In the present study we investigated the effects of patent blue 0.48% on human retinal function.

METHODS

An isolated human retina preparation was perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by a commercially available patent blue solution. The duration of retinal exposure to the dye solution was varied between 15 s and 4 min. Thereupon, the preparation was reperfused with standard solution for 2 h. The percentage of b-wave reduction after exposition was calculated.

RESULTS

No effects on the human ERG were seen after 15 and 30 s of dye application. Reversible reductions of the b-wave amplitude were found for an exposure period of 60 and 120 s, respectively. After 4 min of patent blue application a persistant b-wave amplitude reduction by 40% was found.

CONCLUSIONS

Patent blue affects human retinal function when applied for at least 1 min. However, no irreversible effects on the human ERG were seen even after 2 min of retinal exposure to patent blue. Thus, toxic effects on retinal function after intraoperative short-term application of patent blue 0.48% appear unlikely to occur.

[Diagnosis and therapy of gestational diabetes--comparison of two surveys of established gynecologists in Berlin and Saxonia-Anhalt ]

PURPOSE

The diagnosis and treatment of gestational diabetes mellitus is controversial. We undertook a survey of obstetricians/gynaecologists to identify current screening practices and differences between Saxonia-Anhalt and Berlin.

METHODS

A questionnaire was sent to 267 practicing obstetricians/gynaecologists in Saxonia-Anhalt and 441 in Berlin. The questionnaires included items on the diagnosis and treatment of gestational diabetes.

RESULTS

A response rate of 37 % in Saxonia-Anhalt and 35 % in Berlin was achieved. 90 % of the respondents would welcome the integration of a general screening for gestational diabetes into the standard German prenatal care plan. In spite of this great support only 37 % of the obstetricians/gynaecologists in Saxonia-Anhalt and 36 % in Berlin screened their patients generally. Important risk factors for the screening were rarely or not mentioned.

CONCLUSION AND DISCUSSION

The survey confirms disparate policies regarding the screening for and treatment of gestational diabetes. There are differences between Saxonia-Anhalt and Berlin. This can only be changed by appropriate inclusion in the German prenatal care plan.

Retinal tolerance to dyes

BACKGROUND

Dye solutions for intraoperative staining of epiretinal membranes and the internal limiting membrane improve the visualisation of these thin structures and facilitate their removal. In the present study the authors investigated the effects of indocyanine green 0.05%, trypan blue 0.15%, and patent blue 0.48% on bovine retinal function.

METHODS

Bovine retina preparations were perfused with a standard solution and the electroretinogram (ERG) was recorded repeatedly. After recording of stable ERG amplitudes the nutrient solution was substituted by one of the dye solutions. The duration of retinal exposure to a dye solution was varied between 10 seconds and 2 minutes. Thereupon, the preparation was reperfused with standard solution for at least 115 minutes. The percentage of b-wave reduction after exposition was calculated.

RESULTS

Reductions of the b-wave amplitude were found for each dye solution tested. The effects after application of patent blue and indocyanine green were completely reversible within the recovery time for an exposure period of 60 and 30 seconds, respectively. The application of trypan blue lead to a loss of the b-wave when the retina was exposed for 15 seconds or longer. This effect was only partly reversible within the recovery time.

CONCLUSION

The ERG showed toxic effects of trypan blue after a short period of retinal exposure. The intraocular application of trypan blue should be limited to selected cases. However, intraocular application of indocyanine green and patent blue in a sufficient concentration and taking account of a short period of retinal exposure seems possible.

Implantatexposition nach Viskokanalostomie mit hochvernetzter Hyalurons�ure (SK-GEL�)

BACKGROUND

Lately, the application of intrascleral implants has been increasingly discussed to improve success rates of nonpenetrating surgery for the treatment of open-angle glaucoma.

PATIENTS AND METHODS

A 36-year-old male patient with medically uncontrolled pigmentary glaucoma underwent viscocanalostomy with intrascleral implantation of reticulated hyaluronic acid (SK-GEL) in his right eye.

RESULTS

The immediate postoperative course was unremarkable with control of intraocular pressure without additional glaucoma medications. At first follow-up, 2 weeks post surgery, conjunctival dehiscence with partial extrusion and exposure of the reticulated hyaluronic acid implant was observed. Under topical tobramycin ointment a gradual limbal readaptation of the conjunctiva over the surface of the exposed parts of the implant with formation of a filtration bleb was noted. Therefore, surgical revision remained unnecessary.

CONCLUSIONS

Implant exposure following nonpenetrating antiglaucomatous surgery is a specific complication, which can appear whenever intrascleral implants are used. Depending on the local situation nonsurgical treatment may be successful.

A prospective randomised trial of viscocanalostomy with and without implantation of a reticulated hyaluronic acid implant (SKGEL) in open angle glaucoma

AIM

To prospectively assess the efficacy and complications of viscocanalostomy with a reticulated hyaluronic acid implant (VSRHAI) versus standard viscocanalostomy in patients with medically uncontrolled open angle glaucoma.

METHODS

A consecutive series of 40 patients (40 eyes) with uncontrolled open angle glaucoma underwent non-penetrating antiglaucomatous surgery. After the excision of the deep scleral flap they were randomly assigned to either a standard viscocanalostomy or additional implantation of a reticulated hyaluronic acid implant. Follow up visits were over a period of 12 months after surgery.

RESULTS

The mean preoperative intraocular pressure (IOP) was 26.5 (SD 6.1) mm Hg for all patients enrolled. The mean IOP was 8.1 (SD 5.6) mm Hg 1 day after surgery for the viscocanalostomy group (p<0.001) and 12.0 (SD 5.2) mm Hg for the VSRHAI group (p<0.001). The postoperative IOP difference between the two groups was statistically significant (p = 0.03). The success rate, defined as an IOP lower than 22 mm Hg without medication, was 40% in both groups at 12 months postoperatively (p = 0.90). The number of postoperative complications was equally low for both groups.

CONCLUSIONS

Both surgical procedures, viscocanalostomy and VSRHAI, provide comparable success rates over a 1 year follow up period. The specific intraoperative and postoperative complications of non-penetrating surgery were seen in our series, although the overall rate of postoperative complications proved equally low for both techniques.

[Combined deep sclerectomy and trabeculotomy in congenital glaucoma with complications]

BACKGROUND

Lately there has been growing interest in deep sclerectomy as a therapeutic approach for the management of congenital glaucoma.In theory, its pressure-lowering effect is independent of external filtration, which minimizes the risk of failure due to conjunctival or episcleral scarring. In patients who have failed to benefit from previous filtering procedures and have refractory congenital glaucoma,deep sclerectomy could become an alternative.

PATIENTS AND METHODS

A 3-year-old girl with refractory congenital glaucoma underwent deep sclerectomy in her left eye. Intraoperatively, percolation through the trabeculodescemetic window was weak, so that the procedure was supplemented by a trabeculotomy.

RESULTS

By now, throughout a follow-up period of 20 months, stabilisation of disc cupping and ocular axial length has been achieved without additional glaucoma surgery or medications.

CONCLUSIONS

In patients with congenital glaucoma,the combination of deep sclerectomy with trabeculotomy may provide an additional therapeutic approach whenever the prospect of success appears to be limited with deep sclerectomy alone.

Ultrasound biomicroscopy and its value in predicting the long term outcome of viscocanalostomy

AIMS

To examine whether the early postoperative morphology at the site of sclerectomy, as visualised by ultrasound biomicroscopy (UBM), is an indicator of the mechanisms that lower intraocular pressure (IOP) and/or predictors of the long term outcome of viscocanalostomy.

METHODS

15 eyes of 14 patients with medically uncontrolled open angle glaucoma and no history of surgery underwent viscocanalostomy according to Stegmann's technique. Ultrasound biomicroscopy was performed during the first month after surgery. The following parameters were assessed: dimensions of the intrascleral "lake," presence of a filtering bleb, presence of a subconjunctival cavity or a suprachoroidal hypoechoic area, and the thickness of the residual trabeculocorneal membrane. A complete ophthalmological examination was performed the day before and the day after surgery. Follow up visits were scheduled 1 week, 4 weeks, 6 months, and 12 months after surgery.

RESULTS

At 1 year successful control of IOP (<20 mm Hg) was achieved without further manipulation or medication in six of 15 eyes. The size of the intrascleral "lake" (average 0.62 mm(3)) did not correlate with later IOP; however, a visible route under the scleral flap and accidental perforation of the trabeculocorneal membrane were associated with long term lowering of IOP. Normal thickness of the trabeculocorneal membrane (0.10-0.15 mm) was indicative of IOP control with and without medication. When UBM showed an early collapse of the intrascleral cavity, control of IOP was not achieved. Other UBM findings did not predict long term function.

CONCLUSION

In accordance with previous studies, the authors found that UBM examination is a useful method to evaluate outflow mechanisms after glaucoma surgery. This study shows that UBM imaging of external filtration during the early postoperative period can be used to predict the success of viscocanalostomy. However, to establish conclusively what parameters of UBM predict successful viscocanalostomy a larger number of patients must be studied.

Electrophysiological changes after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in age related macular degeneration

AIM

To evaluate electrophysiological changes after 360 degrees retinotomy and macular translocation for subfoveal choroidal neovascularisation in patients with age related macular degeneration (AMD).

METHODS

A consecutive series of 32 patients suffering from subfoveal choroidal neovascularisation secondary to AMD underwent 360 degrees retinotomy and macular translocation. The ERG served as the main parameter of the study and was recorded 1 day before the translocation surgery and no earlier than 4 weeks after the silicone oil removal.

RESULTS

The scotopic ERG amplitudes were significantly reduced after translocation surgery. Depending on the applied flash luminance the mean b-wave amplitude reduction of the scotopic ERG varied between 67% (0.2 cd.s/m2) and 74% (0.03 cd.s/m2). The a-waves and b-waves of the saturating light response decreased significantly by 46% and 59%, respectively. The photopic a-wave and b-wave amplitudes were significantly lower after the translocation surgery resulting in a mean reduction of 27% and 43%, respectively.

CONCLUSIONS

Although macular translocation may provide the potential of preserving and even restoring vision in patients with subfoveal choroidal neovascular membranes secondary to AMD the present study indicates that a significant electrophysiological decrease is caused by surgical procedures associated with this technique. Further research is necessary to clarify if certain modifications of the surgical procedure are able to substantially reduce the neuroretinal trauma.

Improvement of macular function by membrane differential filtration in diabetic retinopathy

BACKGROUND

Alterations of blood rheology are assumed to substantially contribute to the pathogenesis of diabetic retinopathy. Membrane differential filtration (MDF) is an extracorporeal treatment which is able to optimize rheological parameters by eliminating high molecular weight proteins and lipoproteins from the blood. The present study was designed to investigate the effects of repetitive MDF on visual function in diabetic retinopathy.

METHODS

11 patients (11 eyes) with nonproliferative or inactive proliferative diabetic retinopathy underwent three treatment cycles during a mean period of 18 weeks. The best corrected visual acuity served as the main parameter of the study. The measurement of visual acuity, visual field, biochemical and rheological parameters was carried out 24 hours pre and post each treatment cycle and at follow up. The mean follow up time was 9 weeks during the post treatment period.

RESULTS

Compared to baseline examination the visual acuity improved stepwise by a mean value of 1.4 lines (p = 0.02) after the last treatment and remained stable at follow up (1.3 lines, p < 0.001). The mean defect of the visual field was reduced by 2.8 dB (p = 0.13) after the treatment period and by 2.5 dB (p = 0.016) at follow up, respectively.

CONCLUSIONS

Repetitive treatment with membrane differential filtration is able to improve visual function in patients with diabetic retinopathy. The present study suggests that repetitive membrane differential filtration treatment could be a useful adjunct along with laser treatment to influence the clinical course of diabetic maculopathy.

Effects of protein tyrosine kinase inhibitor genistein on retinal function in superfused vertebrate retina

The aim of this study was to evaluate safe concentrations of genistein for a potential intraocular application using the isolated retina technique on bovine retina preparations. Bovine retinas were isolated and perfused with an oxygen pre-equilibrated standard solution. The electroretinogram (ERG) was recorded as a transretinal potential using silver/silver-chloride electrodes. After recording of stable ERG amplitudes, genistein was added to the solution in different concentrations. The percentage of b-wave reduction under the drug was calculated. We also studied the influence of genistein on the a-wave amplitude. After the addition of aspartate, the b-wave amplitude was reduced continuously until unmasked a-wave amplitudes were reached. Genistein was then added to the aspartate containing perfusate. The percentage of a-wave amplitude reduction under the drug was calculated. Concentrations of 3.3 microMol/l and higher were found to reduce the b-wave amplitude. The a-wave amplitude was not changed by the applied concentrations. The ERG only showed toxic effects from genistein beyond concentrations that were found to inhibit endothelial cell growth in vitro. In previous studies, beneficial effects on trabecular meshwork cells were present for genistein concentrations which are distinctly higher than the maximum nontoxic concentration reported here. It was shown that the photoreceptor layer is not affected at the examined concentration range. Therefore, we attribute the toxic effects to postsynaptic interaction of genistein. Intraocular application of genistein in a sufficient concentration seems possible.

[Does the dissection depth and thickness of the deep scleral flap affect intraocular pressure after viscocanalostomy? A clinico-pathologic correlation]

BACKGROUND

Non-perforating glaucoma surgery preserves the integrity of the trabecular meshwork in order to avoid postoperative hypotony. The purpose of our study was to investigate whether the morphologic variability of the excised deep scleral flap influences the postoperative intraocular pressure (IOP) after viscocanalostomy.

METHODS

Light-microscopy of the deep scleral flap was performed in 17 patients who had undergone viscocanalstomy. Morphologic parameters (thickness and dissection level of the deep scleral flap) were correlated with the postoperative IOP.

RESULTS

The mean thickness of the deep scleral flap was 309 +/- 95 microns; the dissection level was too deep in 5 cases (trabecular tissue excised) and too high in 6 cases (no signs of Schlemm's canal). The max. preop. IOP was 36.2 +/- 8.5 mmHg and came down to 10.6 +/- 5.7 mmHg at day 1 postop. and 12.4 +/- 4.9 mmHg at day 3/4 postop. At a median follow-up of 6 months IOP was 21.7 +/- 5.5 mmHg. A significant correlation between postop. IOP and the morphology of the deep scleral flap could not be demonstrated.

CONCLUSIONS

Variations of the thickness and depth of the deep scleral flap showed little influence on the initial IOP level following viscocanalostomy. Other factors, f.e. the suturing of the external flap or invisible microruptures of the trabecular meshwork, could be of importance for the early postoperative IOP.

Influence of membrane differential filtration on the natural course of age-related macular degeneration: a randomized trial

PURPOSE

Membrane differential filtration is able to optimize rheologic parameters by eliminating high molecular weight proteins and lipoproteins from the blood. Following the hypothesis that these changes result in an improvement of the microcirculation, the authors tested the efficacy of membrane differential filtration in improving visual function in patients with age-related macular degeneration (ARMD).

METHODS

Forty patients (40 eyes) were randomized into two groups. The treatment group was treated five times over a period of 21 weeks. In both groups, 9/20 of the eyes showed subfoveolar subretinal neovascularization. The main parameter of the study was visual acuity (VA). Electroretinogram (ERG), electrooculogram, and macular visual evoked potentials were also recorded. Plasma and whole blood viscosity and erythrocyte aggregation were measured.

RESULTS

The 20 patients treated repeatedly over a period of 21 weeks showed a mean improvement of 0.63 lines (SD 1.8) of VA on Early Treatment Diabetic Retinopathy Study charts. The control group showed a deterioration of 0.94 lines (SD 1.7) compared to VA at baseline examination. The amplitude of the ERG photopic a-wave and the flicker ERG was significantly increased. The rheologic parameters were lowered in all treated patients.

CONCLUSION

Repetitive treatment with membrane differential filtration is able to improve visual acuity of patients with ARMD and the natural course of this disease. Several questions arise from the results of this study. Further research will show if it is possible to optimize the selection of patients for subgroups with predictive responses through morphologic and functional tests and how to create an optimized and individual treatment strategy determined by the quality, intensity, and frequency of treatment sessions.

Massive anterior capsule shrinkage after plate-haptic silicone lens implantation in uveitis

Two patients, both with bilateral uveitis, had synechiolysis, continuous curvilinear capsulorhexis (CCC), phacoemulsification, and in-the-bag implantation of a foldable single-piece plate-haptic silicone intraocular lens (IOL) in 1 eye. Several weeks postoperatively, massive anterior capsule shrinkage with obstruction of the visual axis occurred in both patients. Surgical revision was performed in both eyes. Both patients had CCC and phacoemulsification and confirmed in-the-bag acrylic IOL implantation in the second eye months after surgery in the first eye. Follow-up examinations showed no significant shrinkage of the anterior capsule opening in any eye. In patients with uveitis, intraoperative lens epithelial cell removal, creation of a large CCC, and careful selection of IOL style and material may prevent occlusion of the anterior capsule opening.

Morphological variability of the trabecular meshwork in glaucoma patients: implications for non-perforating glaucoma surgery

BACKGROUND/AIMS

Morphological variability of the trabecular meshwork could be of considerable importance for the proper intraoperative outcome of non-perforating antiglaucomatous surgery, such as deep sclerectomy and viscocanalostomy. The aim of this study was therefore to assess qualitative and quantitative characteristics of the trabecular meshwork in glaucoma patients undergoing trabeculectomy.

METHODS

Trabeculectomy specimens from 177 glaucoma patients were prepared for light microscopy; 100 specimens were found to be suitable for qualitative assessment and quantitative computerised image analysis; measurements were taken of the meridional diameter of Schlemm's canal as well as the thickness of the trabecular meshwork at different positions.

RESULTS

The mean meridional diameter of Schlemm's canal was 290 microm with the smallest values in the young patients with infantile and secondary glaucomas. the thickness of the trabecular meshwork ranged between 50-70 microm in the anterior region and between 100-130 microm for the posterior portion. The thickness of the anterior meshwork significantly decreased with age. The pigmentation of excised trabecular meshwork was found to be weak or even lacking in 68 patients. In 20 glaucoma patients the uveal meshwork was covered by an endothelial layer.

CONCLUSIONS

From the morphological point of view the risk of inadvertent perforation during deep sclerectomy in older, white glaucoma patients should be taken into account even by an experienced surgeon, because the anterior meshwork in these cases is very thin and trabecular pigmentation that can be used as a topographic landmark is often lacking. The functional success of non-perforating glaucoma surgery in many patients may be limited by endothelial covering of the trabecular meshwork.

Intracorneal inclusion of high-molecular-weight sodium hyaluronate following detachment of Descemet's membrane during viscocanalostomy

PURPOSE

Viscocanalostomy in accordance with Stegmann's technique is a new surgical option in the treatment of glaucoma. There are few reports available describing the specific complications of viscocanalostomy. We report a case of intracorneal inclusion of high-molecular-weight sodium hyaluronate following viscocanalostomy.

CASE REPORT

A 66-year-old man with uncontrolled primary open angle glaucoma of his right eye and a history of argon laser trabeculoplasty underwent viscocanalostomy in accordance with Stegmann's technique. During the filling of Schlemm's canal, a limited lysis of Descemet's membrane advanced centrally in the clear cornea adjacent to the site of canalostomy forming an intracorneal bubble of high-molecular-weight sodium hyaluronate. Postsurgical slit-lamp biomicroscopy showed an intracorneal clear bubble within the corneal periphery without evidence of adjacent corneal edema and with no contact between the corneal endothelium and the iris. Follow-up examinations determined that the appearance of the corneal inclusion, essentially, was unchanged, with only a slight tendency of resorption. No signs of corneal scarring or endothelial decompensation could be noted.

CONCLUSION

To date, we could not determine a significant corneal damage in conjunction with the described complication. However, it is difficult to predict the long-term clinical course of our patient. Corneal decompensation as a result of possible endothelial toxicity of high-molecular weight sodium hyaluronate as well as spontaneous absorption seem possible.

Variability of dissection depth in deep sclerectomy: morphological analysis of the deep scleral flap

BACKGROUND

Deep sclerectomy and similar procedures including a deroofing of Schlemm's canal are meeting with increasing interest owing to the limited risk profile of non-perforating glaucoma surgery. The aim of our study was to investigate how often the outer wall of Schlemm's canal or parts of the trabecular meshwork were incorporated in the excised tissue on deep scleral flap dissection by an experienced glaucoma surgeon.

METHODS

The excised deep scleral flap was prepared for light microscopy after performing deep sclerectomy in 7 children and 22 adult patients suffering from glaucoma. Meridional serial sections were checked for the presence of fragments of trabecular beams and collector channels and parts of the endothelial wall of Schlemm's canal. Morphology was compared with the intraoperative appearance of the operated tissue.

RESULTS

In 15 patients (52%) the deep scleral flap contained at least some tissue from the outer wall of Schlemm's canal; in 5 of these 15 patients noticeable remnants of the juxtacanalicular trabecular meshwork were also found, although only in one patient was this obvious during surgery. In 14 patients (48%) no evidence of the deroofing of Schlemm's canal was found within the excised deep scleral flap, although intraoperatively the dissection seemed to have been too superficial in only 5 patients.

CONCLUSION

Even when performed by an experienced glaucoma surgeon, deep sclerectomy produces biopsy material of remarkable morphological variability that does not always correspond to the intraoperative appearance of the site of operation. More than in conventional trabeculectomy this variability may be of importance for the outcome of surgery.

Improvement of visual acuity in patients suffering from diabetic retinopathy after membrane differential filtration: a pilot study

BACKGROUND

Membrane differential filtration is an extracorporeal treatment procedure which eliminates high molecular weight proteins and lipids from the blood. This pilot study was initiated to investigate the short-term effects on blood rheology and visual function in patients suffering from diabetic retinopathy.

METHODS

Six patients with non-proliferative diabetic retinopathy, clinically significant macular edema (five patients, nine eyes) and inactive proliferative diabetic retinopathy (one patient, one eye) underwent a single treatment with a hollow fiber secondary plasma filter. The main parameter measured was visual acuity prior to and after treatment. Biochemical and rheological parameters (whole blood and plasma viscosity, and erythrocyte aggregation) were also measured. The mean follow-up was 25 (range 4-90) days after treatment.

RESULTS

The mean improvement of visual acuity was 1.4 lines (SD 0.8 lines, p = 0.002) 24 h after therapy. This remained stable during the follow-up period. The rheological measures were significantly lowered. A significant reduction of total protein, fibrinogen, IgG, IgM, IgA, alpha-2-macroglobulin, total cholesterol, LDL and HDL was found.

CONCLUSION

This study demonstrates the rheological impact of membrane differential filtration. It was shown that rheological changes correlated with clinical improvement in patients suffering from diabetic retinopathy with clinically significant macular edema.

Electrophysiological abnormalities in age-related macular degeneration

BACKGROUND

Results from psychophysical tests indicate that in age related macular degeneration (ARMD) retinal function is globally impaired. Observations in single ARMD cases showing abnormalities of the electrooculogram (EOG) and electroretinogram (ERG) encouraged us to systematically examine ARMD patients by means of electrophysiological tests to confirm a global retinal dysfunction in ARMD.

METHODS

Sixty-six patients with ARMD were examined clinically and by means of EOG, ERG, triple scotopic ERG, and fluorescein angiography (FA).

RESULTS

EOG data were considerably reduced in ARMD. Scotopic a- and b-waves of the ERG were mildly affected. The bright flash response showed reduced b-waves with normal implicit times. The amplitude of the oscillatory potential OP2 was significantly reduced and photopic responses were also pathologic compared with an age-matched control group. Geographic atrophy and pigment epithelium detachment showed specific abnormalities in the ERG, whereas in soft drusen EOG changes were more conspicuous.

CONCLUSIONS

In addition to data from psychophysical tests the results from electrophysiological examinations indicated a global reduction of retinal function in ARMD which seemed to be present not only in the macula but also elsewhere in the retina.

[Current strategies for treatment of CMV retinitis in patients with AIDS]

BACKGROUND

CMV retinitis is the most common manifestation of active CMV infection in patients with AIDS. Before ganciclovir became available, the prognosis of CMV retinitis was very poor. Meanwhile a number of strategies for the management of CMV retinitis have evolved. To date no antiviral agent has proved effective in preventing reactivation of retinitis. Therefore the available antiviral agents delay rather than prevent relapse of CMV retinitis. Each relapse produces a more serious disease and retinitis becomes progressively less manageable.

METHOD

A review of current therapeutic strategies for the treatment of CMV retinitis with regard to the challenge of clinical resistance is given.

CONCLUSION

Effective treatment of clinically resistant CMV retinitis must consider the individual conditions. Thus, it is probable, that integration of both local and systemic therapies may be required to reduce the frequency of reactivation and thereby to decelerate the progression of the disease. Literature search in medline.

Antibiotics and light responses in superfused bovine retina

1. Our objective was to study effects of clindamycin and ciprofloxacin on the electroretinogram (ERG) of isolated bovine retinas. 2. Electroretinograms of isolated superfused bovine retinas were recorded under normal conditions and during application of clindamycin and ciprofloxacin. The b-wave reduction was plotted against the drug concentration. In several cases retinal oxygen uptake was also measured. Clindamycin was available only in a preparation containing benzyl alcohol. To differentiate between effects caused by the antibiotic and the alcohol, ERGs were also recorded under superfusion with benzyl alcohol. To record drug effects on photoreceptors synaptic transmission was blocked using 1 mM aspartate. 3. At concentrations between 0.3 and 10 mM clindamycin significantly reduced the amplitude of the b-wave of the ERG. A comparable reduction of retinal oxygen uptake was found at concentrations 10-fold higher. Clindamycin, 3 mM, did not affect the a-wave after preincubation with aspartate. Benzyl alcohol at concentrations of 0.3 and 1 mM did not affect the b-wave, whereas at higher concentrations the b-wave was found to be reduced. Considerable b-wave reductions were found with ciprofloxacin at concentrations of between 0.03 and 0.6 mM. All effects proved to be fully reversible and dose-dependent. 4. Ciprofloxacin and clindamycin did both alter neural function in the isolated superfused bovine retina. The nontoxic dosages found here differ considerably from results in rabbits after intravitreal injections. This is probably due to species differences.

The triple flash electroretinogram and its significance in macular diseases. B-wave recovery as a diagnostic tool

PURPOSE

The purpose of this study was to evaluate recovery data for the b-wave of the electroretinogram (ERG) elicited using multiple flash stimulation with increasing stimulus intervals in normal controls and in patients with macular diseases. The results will describe effects of age and macular disease and define indexes characterizing the recovery process.

METHODS

Scotopic Ganzfeld flash ERGs were elicited using interstimulus intervals of 140, 280, and 560 ms. Relative b-waves were calculated as the ratio b140 ms/b560 ms and b280 ms/b560 ms, respectively. Responses obtained in 134 eyes of 134 normal controls served as reference data. Fifty-four patients with different macular diseases were also examined and their data compared to the reference data.

RESULTS

Relative b-wave amplitudes correlated with interstimulus interval and with flash luminance, but not with age. All patients had a normal ERG when recorded following the standard of clinical electroretinography. A sigmoidal model was suggested, providing three indexes characterizing the b-wave recovery process. Relative b-waves and recovery indexes varied in age-related macular degeneration, central serous retinopathy, vitelliform macular degeneration, Stargardt's disease, and pattern dystrophy.

CONCLUSION

The triple flash ERG reflects energy-yielding and -utilizing mechanisms. It proved to be more sensitive in detecting functional lesions in macular diseases than the standardized explorating procedure. The b-wave recovery model allows differentiation between two independent mechanisms contributing to the b-wave recovery process. One or more of the three characterizing indexes are affected in different macular diseases.