Altered immune responses in interleukin 10 transgenic mice

Interleukin (IL)-10 is a pleiotropic cytokine which inhibits a broad array of immune parameters including T helper cell type 1 (Th1) cytokine production, antigen presentation, and antigen-specific T cell proliferation. To understand the consequences of altered expression of IL-10 in immune models of autoimmune disease, the response to infectious agents, and the response to tumors, we developed transgenic mice expressing IL-10 under the control of the IL-2 promoter. Upon in vitro stimulation, spleen cells from unimmunized transgenic mice secrete higher levels of IL-10 and lower amounts of IFN-gamma than do controls, although no gross abnormalities were detected in lymphocyte populations or serum Ig levels. Transfer of normally pathogenic CD4(+) CD45RBhigh splenic T cells from IL-10 transgenic mice did not cause colitis in recipient severe combined immunodeficiency mice. Furthermore, co-transfer of these transgenic cells with CD4(+) CD45RBhigh T cells from control mice prevented disease. Transgenic mice retained their resistance to Leishmania major infection, indicating that their cell-mediated immune responses were not globally suppressed. Lastly, in comparison to controls, IL-10 transgenic mice were unable to limit the growth of immunogenic tumors. Administration of blocking IL-10 mAbs restored in vivo antitumor responses in the transgenic mice. These results demonstrate that a single alteration in the T cell cytokine profile can lead to dramatic changes in immune responses in a manner that is stimulus dependent. These mice will be useful in defining differences in inflammatory conditions and cellular immunity mediated by IL-10.

Transplantation of the RPE in AMD

The retinal pigment epithelium (RPE) maintains retinal function as the metabolic gatekeeper between photoreceptors (PRs) and the choriocapillaries. The RPE and Bruch's membrane (BM) suffer cumulative damage over lifetime, which is thought to induce age-related macular degeneration (AMD) in susceptible individuals. Unlike palliative pharmacologic treatments, replacement of the RPE has a curative potential for AMD. This article reviews mechanisms leading to RPE dysfunction in aging and AMD, laboratory studies on RPE transplantation, and surgical techniques used in AMD patients. Future strategies using ex vivo steps prior to transplantation, BM prosthetics, and stem cell applications are discussed. The functional peculiarity of the macular region, epigenetic phenomena leading to an age-related shift in protein expression, along with the accumulation of lipofuscin may affect the metabolism in the central RPE. Thickening of BM with age decreases its hydraulic conductivity. Drusen are deposits of extracellular material and formed in part by activation of the alternative complement pathway in individuals carrying a mutant allele of complement factor H. AMD likely represents an umbrella term for a disease entity with multifactorial etiology and manifestations. Presently, a slow progressing (dry) non-neovascular atrophic form and a rapidly blinding neovascular (wet) form are discerned. No therapy is currently available for the former, while RPE transplantation and promising (albeit non-causal) anti-angiogenic therapies are available for the latter. The potential of RPE transplantation was demonstrated in animal models. Rejection of allogeneic homologous transplants in patients focused further studies on autologous sources. In vitro studies elucidated cell adhesion and wound healing mechanisms on aged human BM. Currently, autologous RPE, harvested from the midperiphery, is being transplanted as a cell suspension or a patch of RPE and choroid in AMD patients. These techniques have been evaluated from several groups. Autologous RPE transplants may have the disadvantage of carrying the same genetic information that may have led to AMD manifestation. An intermittent culturing step would allow for in vitro therapy of the RPE, its rejuvenation and prosthesis of BM to improve the success RPE transplants. Recent advances in stem cell biology when combined with lessons learned from studies of RPE transplantation are intriguing future therapeutic modalities for AMD patients.

Posterior vitreomacular adhesion: a potential risk factor for exudative age-related macular degeneration?

PURPOSE

To compare the state of the posterior vitreous in exudative age-related macular degeneration (AMD) with eyes with nonexudative AMD and controls.

DESIGN

Prospective, observational case series.

METHODS

B-scan ultrasonography and optical coherence tomography (OCT) were performed in 163 eyes from 82 subjects older than 55 years, 50 eyes with exudative AMD, 57 with nonexudative AMD, and 56 control eyes. Main outcome measures were the number of eyes with complete posterior vitreous detachment (PVD) by ultrasound and the number of eyes with central vitreomacular adhesion by OCT.

RESULTS

By ultrasonography, 17 (34.0%) of 50 eyes with exudative AMD had PVD as compared with 41 (71.9%) of 57 eyes with nonexudative AMD (P = .00002) and 34 (60.7%) of 56 controls (P = .017). OCT detected persistent central vitreoretinal adhesion surrounded by a detached posterior vitreous cortex in 18 (36%) of 50 eyes with exudative AMD, significantly higher than in nonexudative AMD (4/57 [7%]; P < .0001) and in controls (6/56 [10%]; P = .002).

CONCLUSIONS

Persistent attachment of the posterior vitreous cortex to the macula may be another risk factor for the development of exudative AMD via vitreoretinal traction inducing chronic low-grade inflammation, by maintaining macular exposure to cytokines or free radicals in the vitreous gel, or by interfering in transvitreous oxygenation and nutrition of the macula. Inducing PVD may provide prophylactic benefit against exudative AMD.

Spectral-domain optical coherence tomography for monitoring epiretinal membrane surgery

PURPOSE

To assess prognostic factors in epiretinal membrane (ERM) surgery using spectral-domain (SD) optical coherence tomography (OCT).

DESIGN

Prospective, interventional case series.

PARTICIPANTS

Forty-one patients.

METHODS

Patients with a diagnosis of ERM were examined with spectral-domain and time-domain (TD) OCT before and after surgery.

MAIN OUTCOME MEASURES

Main outcome measures were functional results and predefined OCT patterns. Cofactors analyzed were the type of ERM, the duration and grading of subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, and age. A multivariate regression analysis was performed.

RESULTS

Thirty-nine patients (95%) showed an improved or stable best-corrected distance visual acuity (DVA) at 3 months, whereas 36 patients (88%) showed an improved or stable best-corrected near visual acuity (NVA) at 3 months. Significant correlations (P>0.4) were found between the course of central retinal thickness (CRT) assessed using SD OCT and TD OCT (P<0.02). No clinically relevant correlations (P<0.3) were seen between CRT and VA (P>0.1). Baseline DVA and NVA were found to be significant prognostic values for the postoperative decrease in CRT in both OCT systems (P<0.04) as well as for the visual outcomes (P<0.007) at 3 months. In addition, the integrity of the junction between the photoreceptor inner segment and outer segment (IS/OS) significantly influenced the visual outcomes at 3 months (P<0.038). The baseline profile of the internal limiting membrane (ILM) significantly influenced the NVA at 3 months (P<0.009), whereas the postoperative foveal contour significantly influenced the DVA at 3 months (P<0.025). The type of ERM, subjective metamorphopsia, simultaneous cataract surgery, the type of dyes used, the duration of surgery, gender, or age had no significant influence on patient outcome (P>0.05). Compared with TD OCT, SD OCT allowed for a more precise differentiation between the ERM and the retinal surface and for a better evaluation of the IS/OS line.

CONCLUSIONS

Besides the baseline VA, the integrity of the IS/OS line, better visualized by SD OCT, can be used to predict the functional outcomes after surgery. Additionally, analyzing the ILM profile and the foveal contour may help to understand limited visual outcomes after surgery.

FINANCIAL DISCLOSURE(S)

The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Transplantation of autologous retinal pigment epithelium in eyes with foveal neovascularization resulting from age-related macular degeneration: a pilot study

PURPOSE

To describe the indications, surgical technique, and clinical results of 14 eyes in 13 patients with age-related macular degeneration and foveal choroidal neovascularization, in which subretinal surgery was combined with simultaneous transplantation of autologous retinal pigment epithelial cells.

METHODS

Between March 1999 and February 2000, in a prospective study, 14 eyes (13 patients) with age-related macular degeneration underwent subretinal surgery because of foveal choroidal neovascularization with simultaneous transplantation of retinal pigment epithelium harvested from the nasal subretinal area of the same eye. Preoperatively, 1 month postoperatively, 3 months postoperatively and at 3-month intervals thereafter, examinations were performed including best-corrected visual acuity, visual field, biomicroscopy of anterior and posterior segment, tonometry, fluorescein and indocyanine angiographies, autofluorescence, scotometry, and fixation tests.

RESULTS

Postoperatively, after median observation of 17 months (range, 12 to 24 months) best-corrected visual acuity was improved 2 or more lines in eight eyes (57.1%), remained the same (+/- 1 line) in five eyes (35%), and decreased by more than 2 lines in one eye (7.1%). Pairwise t test showed significant improvement after 1 month (P = .0031, P = .0062) as well as 1 year (P = .0066, P = .0105). Satisfactory reading vision between Jaeger 1 and 4 was achieved in three eyes (21.2%). No significant intraoperative or postoperative complications occurred in any eye. No recurrence of choroidal neovascularization was observed during the observation period.

CONCLUSIONS

In eyes with age-related macular degeneration and foveal choroidal neovascularization, autotransplantation of retinal pigment epithelium was performed in addition to conventional removal of the choroidal neovascularization without significant intraoperative or postoperative complications. Visual acuity improvement of 2 or more lines in 57% of the eyes was achieved. No recurrent choroidal neovascularization formation was observed during the observation period. The results of this pilot study suggest that autologous transplantation of retinal pigment epithelium combined with submacular surgery might be a reasonable treatment option for patients with foveal choroidal neovascularization secondary to age-related macular degeneration.

Emerging infectious diseases: public health issues for the 21st century

Infectious diseases are the third leading cause of death in the United States and the leading cause worldwide. As the new millennium approaches, the public health community must replenish capacity depleted during years of inadequate funding while simultaneously incorporating new technologies and planning for the longer term. Among the challenges facing the public health community is the need for coordinated, global, multisectoral approaches to preventing and controlling complex infectious disease problems.

Outcome of transplantation of autologous retinal pigment epithelium in age-related macular degeneration: a prospective trial

PURPOSE

To present the outcome of a consecutive series of patients who had foveal choroidal neovascularization (fCNV) in age-related macular degeneration (AMD) and were treated with subretinal surgery combined with simultaneous transplantation of autologous retinal pigment epithelial (RPE) cells.

METHODS

Patients with fCNV who were not eligible for laser or photodynamic therapy were included in the study. They underwent subretinal membrane excision with simultaneous transplantation of autologous RPE cells. Eyes with membrane excision alone served as the control. Tests included best corrected visual acuity for far and near with Early Treatment Diabetic Retinopathy Study (ETDRS) and Jaeger charts, multifocal (mf)ERG, central visual field analysis, optical coherence tomography (OCT), and angiography, before surgery, and 1 month and 3 months after treatment, and at 3-month intervals thereafter.

RESULTS

The results of final examinations of 53 eyes are presented. In 39 eyes, RPE transplantation was performed (group 1); 14 eyes had membrane excision alone (group 2). In group 1, visual acuity improved significantly, two or more lines in 21 (53.8%) patients; remained stable in 12 patients (30.8%); and decreased two or more lines in 6 patients (15.4%; P=0.0062). In group 2, the corresponding values were 21.1%, 57.8%, and 21.1% (P=0.5377 NS). Statistical analysis of results in the two groups showed a trend in favor of group 1 (P=0.9714). The difference in reading acuity was significant between the two groups (mean change in group 1: 1.85 +/- 0.42 vs. 0.43 +/- 0.47 in group 2; P=0.0001). mfERG response density changes were significantly different between groups 1 and 2 (P=0.0094). No significant decreases in central visual field defects were detected. OCT showed the postoperative median retinal thickness in the lesion area in group 1 to be higher (242.31 +/- 12.30 microm) than in group 2 (202.07 +/- 10.68 microm), showing a trend (P=0.0682).

CONCLUSIONS

Patients undergoing fCNV removal with autologous transplantation of RPE reached significantly better reading acuity and higher mfERG-response density than control subjects. The results provide evidence that autologous transplantation of RPE is a beneficial supplement to membrane excision alone in patients with fCNV in AMD and may be regarded as a reasonable treatment option.

RNA editing

The term RNA editing describes those molecular processes in which the information content is altered in an RNA molecule. To date such changes have been observed in tRNA. rRNA and mRNA molecules of eukaryotes, but not prokaryotes. The demonstration of RNA editing in prokaryotes may only be a matter of time, considering the range of species in which the various RNA editing processes have been found. RNA editing occurs in the nucleus, as well as in mitochondria and plastids, which are thought to have evolved from prokaryotic-like endosymbionts. Most of the RNA editing processes, however, appear to be evolutionarily recent acquisitions that arose independently. The diversity of RNA editing mechanisms includes nucleoside modifications such as C to U and A to I deaminations, as well as non-templated nucleotide additions and insertions. RNA editing in mRNAs effectively alters the amino acid sequence of the encoded protein so that it differs from that predicted by the genomic DNA sequence.

A nuclear gene encoding mitochondrial Delta-pyrroline-5-carboxylate dehydrogenase and its potential role in protection from proline toxicity

Delta1-pyrroline-5-carboxylate (P5C), an intermediate in biosynthesis and degradation of proline (Pro), is assumed to play a role in cell death in plants and animals. Toxicity of external Pro and P5C supply to Arabidopsis suggested that P5C dehydrogenase (P5CDH; EC 1.2.1.12) plays a crucial role in this process by degrading the toxic Pro catabolism intermediate P5C. Also in a Deltaput2 yeast mutant, lacking P5CDH, Pro led to growth inhibition and formation of reactive oxygen species (ROS). Complementation of the Deltaput2 mutant allowed identification of the Arabidopsis P5CDH gene. AtP5CDH is a single-copy gene and the encoded protein was localized to the mitochondria. High homology of AtP5CDH to LuFIS1, an mRNA up-regulated during susceptible pathogen attack in flax, suggested a role for P5CDH in inhibition of hypersensitive reactions. An Arabidopsis mutant (cpr5) displaying a constitutive pathogen response was found to be hypersensitive to external Pro. In agreement with a role in prevention of cell death, AtP5CDH was expressed at a basal level in all tissues analysed. The highest expression was found in flowers that are known to contain the highest Pro levels under normal conditions. External supply of Pro induced AtP5CDH expression, but much more slowly than Pro dehydrogenase (AtProDH) expression. Uncoupled induction of the AtProDH and AtP5CDH genes further supports the hypothesis that P5C levels have to be tightly controlled. These results indicate that, in addition to the well-studied functions of Pro, for example in osmoregulation, the Pro metabolism intermediate P5C also serves as a regulator of cellular stress responses.

25-gauge vs 20-gauge system for pars plana vitrectomy: a prospective randomised clinical trial

AIM

To compare 25-gauge vs 20-gauge system for pars plana vitrectomy in a prospective, randomised, controlled clinical trial.

METHODS

Three-port pars plana vitrectomy was performed in 60 patients belonging to 2 groups. Evaluations were performed preoperatively, intraoperatively, during the first three postoperative days, at 1 week, and at 1 and 3 months. The main outcome measure was time for surgery, divided into duration of wound opening, vitrectomy, retinal manipulation and wound closure.

RESULTS

The total duration of surgery showed no significant difference between the groups (p = 0.67). The 25-gauge group showed significantly shorter duration of wound opening (p<0.001) and wound closure (p<0.001). In contrast, the vitrectomy duration was significantly longer in the 25-gauge group (p<0.001). Conjunctival injection and subjective postoperative pain showed significantly lower irritation in the 25-gauge group (p<0.001 for both).

CONCLUSION

The 25-gauge vitrectomy system offered significantly improved patient comfort during the first postoperative week. The smaller surgical openings facilitated wound healing and minimised pain. Duration of surgery was comparable between the two systems-the shorter time needed for wound opening and closure in the 25-gauge group being equalised by the longer vitrectomy duration. Intraoperative as well as retinal manipulation and illumination caused more surgical difficulties using the 25-gauge system.

Vitreomacular adhesion in active and end-stage age-related macular degeneration

PURPOSE

To evaluate vitreomacular relations in different stages of age-related macular degeneration (AMD) without the influence of genetics and environmental factors.

DESIGN

Retrospective, observational case series.

METHODS

This was a multicenter study consisting of 29 previously untreated subjects with active exudative (wet) AMD in one eye and active nonexudative (dry) AMD in the fellow eye who were compared with 10 previously untreated subjects with end-stage geographic atrophy in one eye and an end-stage fibrotic (disciform) scar in the fellow eye. All subjects were studied with ultrasonography to identify the presence of posterior vitreous detachment (PVD) and by optical coherence tomography to detect vitreomacular adhesion (VMA).

RESULTS

The incidence of PVD in eyes with nonexudative AMD was 20 (69%) of 29, compared with 6 (21%) of 29 with active exudative AMD (P = .002). VMA was present in 11 (38%) of 29 of eyes with exudative AMD and in only 3 (10%) of 29 eyes with nonexudative AMD (P = .008). The incidence of PVD in geographic atrophy was 7 (70%) of 10, compared with 4 (40%) of 10 with disciform scar (P = .44). VMA was present in 2 (20%) of 10 eyes with disciform scars and in 0 (0%) of 10 eyes with geographic atrophy (P = .48).

CONCLUSIONS

PVD may protect against exudative AMD, whereas VMA may promote exudative AMD. This phenomenon is not evident in end-stage disease because of an increased incidence of PVD and a decreased incidence of VMA in eyes with disciform scars. Genetic and environmental factors do not seem to influence these observations.

Update on ocular complications of systemic cancer chemotherapy

The constantly growing list of cytotoxic chemotherapeutics requires a new survey of ophthalmic complications, which are often underestimated. Based on the review by Imperia et al (1989), an update on ophthalmic complications of currently used cytotoxic chemotherapeutics in oncology was written. Vision is a quality of life issue, which must be nurtured, especially if loss of vision can be prevented. The broad spectrum of ophthalmic complications induced by cytotoxic chemotherapy includes reversible and irreversible acute and chronic disorders. Mild to moderate ophthalmic complications are very common and reversible after cessation of anti-cancer therapy. Some major ocular toxicities may require a dose reduction or the discontinuation of cytotoxic chemotherapy in order to prevent visual loss. Ocular toxicities can be treated or even prevented, if detected early enough. That is why an ophthalmic baseline examination for patients receiving cytosine arabinoside, 5-fluorourocil, methotrexate, or docetaxel should be taken into consideration, and a consultation with an ophthalmologist has to be done as soon as symptoms are recognized. Oncologists and ophthalmologists must be aware of potential ophthalmic complications during cytotoxic chemotherapy, and should work together.

Outcome after silicone oil removal

BACKGROUND

Combined with vitreoretinal surgery, silicone oil injection has become a standard technique and improves the prognosis of complex retinal detachment. As silicone oil leads to long term complications, removal of silicone oil from the eye is recommended. To evaluate the outcome after silicone oil removal, retinal redetachment, visual acuity, and complications were analysed.

METHODS

The authors analysed 115 consecutive cases of silicone oil removal (115 eyes), all operated by one surgeon. The series consisted of retinal detachments associated with proliferative vitreoretinopathy (103 eyes), proliferative diabetic retinopathy (six eyes), or ocular trauma (six eyes). The mean duration of intraocular silicone oil tamponade was 13.3 months, with a mean postoperative follow up of 1.8 years.

RESULTS

Anatomic success after silicone oil removal, defined as a complete retinal attachment, was achieved in 95 of 115 eyes (82.6%). Redetachment occurred in 20 eyes (17.4%), mostly within the first 6 months after silicone oil removal. Including the successfully reoperated eyes, the authors present a final anatomic success rate of 108 eyes (93.9%). Visual acuity improved or remained unchanged in 93 eyes (80.9%).

CONCLUSION

While reattachment and complication rates were quite similar to other studies, a better visual outcome was achieved in these cases. The duration of the silicone oil tamponade had no significant effect on the reattachment rate. The authors recommend not to apply standard criteria for the timing of silicone oil removal, but to decide individually, considering the underlying disease, as well as the previous operations.

A novel class of autoantigens of anti-neutrophil cytoplasmic antibodies in necrotizing and crescentic glomerulonephritis: the lysosomal membrane glycoprotein h-lamp-2 in neutrophil granulocytes and a related membrane protein in glomerular endothelial cells

Necrotizing and crescentic glomerulonephritis (NCGN) is frequently associated with circulating antineutrophil cytoplasmic autoantibodies (ANCA). It is established that ANCA are specific for soluble enzymes of granules of polymorphonuclear neutrophil granulocytes (PMN), such as myeloperoxidase (MPO) or protease 3 (PR3). The purpose of this study was to identify membrane proteins of PMNs, and/or glomerular cells, as additional autoantigenic ANCA targets. When membrane protein fractions were prepared from PMNs and isolated human glomeruli, and immunoblotted with ANCA sera of NCGN patients, two bands with apparent molecular masses of 170 and 80-110 kD (gp170/80-110) were labeled in PMNs, and a 130-kD glycoprotein (gp130) in glomeruli. Gp130 was purified, and monoclonal and rabbit antibodies (Abs) were produced which showed the same double specificity as the patient's ANCA. Using these probes, evidence was provided that gp170/80-110 is identical with human lysosomal-associated membrane protein 2 (h-lamp-2), because both proteins were immunologically cross-reactive and screening of a cDNA expression library from human promyelocytic leukemia cells with anti-gp130 Ab yielded a clone derived from h-lamp-2. Gp170/80-110 was localized primarily in granule membranes of resting PMNs, and was translocated to the cell surfaces by activation with FMLP. By contrast, gp130 was localized in the surface membranes of endothelial cells of human glomerular and renal interstitial capillaries, rather than in lysosomes, as found for h-lamp-2. Potential clinical relevance of autoantibodies to gp170/80-110 and gp130 was assessed in a preliminary trial, in which ANCA sera of patients (n = 16) with NCGN were probed with purified or recombinant antigens. Specific reactivity was detected in approximately 90% of cases with active phases of NCGN, and frequently also in combination with autoantibodies specific for PR3 or MPO. Collectively, these data provide evidence that h-lamp-2 in PMNs and a different, structurally related 130-kD membrane protein on the cell surface of renal microvascular endothelial cells are autoantigenic targets for ANCA in patients with active NCGN.

Human retinal pigment epithelium (RPE) transplantation: outcome after autologous RPE-choroid sheet and RPE cell-suspension in a randomised clinical study

AIMS

To evaluate the outcome after two types of retinal pigment epithelium (RPE) transplantation techniques.

METHODS

Fourteen consecutive patients with advanced exudative age-related macular degeneration (AMD) were randomly assigned to RPE-choroid sheet transplantation (group 1) or RPE cell-suspension transplantation (group 2). Outcome measures included best corrected distance and near visual acuity (BCVA), complication and recurrence rates, autofluorescence (AF), angiography, and time-domain and spectral-domain optical coherence tomography (TD- and SD-OCT).

RESULTS

A gain of three or more lines in BCVA at 24&emsp14;months was found in two patients in group 1 and in one patient in group 2, whereas a loss of vision of three or more lines occurred in one patient in each group. Revision surgery for proliferative vitreoretinopathy was required in one patient in group 1. Epiretinal membranes developed in two patients in group 1 and in one patient in group 2. No recurrence occurred in this series. AF showed hyperfluorescence coincident with the graft in group 1, and hyper- and hypofluorescence in irregular patterns in group 2. Revascularisation of the graft was present in all patients in group 1, and a normal choroidal vasculature in the area of RPE atrophy in all patients in group 2. OCT showed a decrease in retinal thickness in all patients, with an improved visualisation of inter- and intralaminar structures with SD-OCT.

CONCLUSION

The anatomical and functional outcome after both RPE transplantation techniques was comparable. Intrastructural irregularities of the sheet assessed using SD-OCT might explain the rather limited visual gain in otherwise successful sheet transplants. Clinical Trial Registration NCT00401713.

Seizure control and acceptance of the ketogenic diet in GLUT1 deficiency syndrome: a 2- to 5-year follow-up of 15 children enrolled prospectively

BACKGROUND

GLUT1 deficiency syndrome is caused by impaired glucose transport into the brain resulting in an epileptic encephalopathy, developmental delay, and a complex motor disorder. A ketogenic diet provides an alternative fuel to the brain and effectively restores brain energy metabolism.

METHODS

Fifteen children with GLUT1 deficiency syndrome were enrolled prospectively for a 2.0 - 5.5-year follow-up of the effectiveness of a 3 : 1 LCT ketogenic diet. Eight patients enrolled were described previously, seven patients were novel.

RESULTS

Four novel heterozygous GLUT1 mutations were identified. 10/15 patients remained seizure-free on the ketogenic diet in monotherapy. In 2/15 patients seizures recurred after 2(1/2) years despite adequate ketosis, but were controlled by add-on ethosuximide. In one patient seizures were reduced without complete seizure control. No serious adverse effects occurred and parental satisfaction with the diet was good. 2/15 patients discontinued the diet.

CONCLUSION

GLUT1 deficiency syndrome represents a complex childhood encephalopathy that can be treated effectively by means of a ketogenic diet. The response to the diet did not correlate to clinical, biochemical, or genetic features of the disease. In contrast to previous reports, our results indicate that epilepsy is not always completely controlled by a ketogenic diet and can recur in a subset of patients.

Non-responders to treatment with antagonists of vascular endothelial growth factor in age-related macular degeneration

PURPOSE

Most of the publications on modern therapy of neovascular age-related macular degeneration focus on the effect of the treatment. The purpose of this study is to determine the frequency of non-responders to anti-vascular endothelial growth factor (anti-VEGF) treatment and find possible reasons for their failure to respond.

METHODS

The records of patients treated until the end of 2008 the first time with either bevacizumab or ranibizumab were reviewed. Based on the availability of measurable results and according to prior publications showing the effect of the therapy, loss of three lines of distance acuity, increase of retinal thickness or lesion size were identified as indicators of non-responders. Two of these three signs had to be present.

RESULTS

334 eyes of 283 patients were included; 74.55% received bevacizumab and 25.45% received ranibizumab. Overall 14.37% of the eyes were identified as non-responders (14.06% in the bevacizumab group and 15.29% in the ranibizumab group). Baseline distance acuity and vitreo-retinal adhesions were significantly correlated with non-responders. Correlations with age, gender, lesion type, other morphologic features, and the kind of anti-VEGF agent failed to be significant. 10.4% of the non-responders showed a delayed but good response to anti-VEGF treatment.

CONCLUSIONS

About 15% did not sufficiently respond to anti-VEGF treatment. Vitreo-retinal adherences were the only ophthalmologic factor which could be identified to be significantly correlated with insufficient response.

Estimating soil ingestion: the use of tracer elements in estimating the amount of soil ingested by young children

In this pilot study, we modified methods used in estimating the amount of soil ingested by ruminants to measure soil ingested by children. Using aluminum, silicon, and titanium as tracers, we estimated soil ingestion for 59 children aged 1-3 yr from East Helena, Montana. Estimated daily soil ingestion based on aluminum and silicon concentrations were 181 and 184 mg/day, respectively, whereas the estimate based on the titanium concentration was about 10 times higher, 1,834 mg/day. Although we do not consider these estimates accurate measures of soil ingestion, the method we used is a reasonable approach that, to our knowledge, has not been used before in humans. However, our estimates will be revised as refinement of this method and better understanding of the metabolism of aluminum, silicon, and titanium lead to more accurate data for analysis.

RNA degradation buffers asymmetries of transcription in Arabidopsis mitochondria

To understand better the relative contributions of transcriptional and post-transcriptional processes towards the regulation of gene expression in plant mitochondria, we compared the steady state levels of RNAs with the respective transcriptional activities. All of the protein and rRNA coding genes of the Arabidopsis mitochondrial genome and several orfs were analyzed by run-on and northern experiments. rRNAs constitute the bulk of the steady state RNA in Arabidopsis mitochondria, but are (different from maize mitochondria) not equally prominent among the run-on transcripts. Their relatively low rate of active transcription is apparently compensated by their high stability. Run-on transcription values differ significantly between genes coding for different subunits of the same protein complex. The steady state RNA levels are considerably more homogeneous, indicating that high variations of transcription rates are counterbalanced by post-transcriptional processes. The relative amounts of the steady state transcripts for the different subunits in a given protein complex reflect the relative stoichiometries of the protein subunits much more closely than the respective transcriptional activities. Post-transcriptional RNA processing and stability thus contribute significantly to the regulation of gene expression in Arabidopsis mitochondria.

Minimum distance mapping using three-dimensional optical coherence tomography for glaucoma diagnosis

Objective imaging of the optic nerve structure has become central to the management of patients with glaucoma. There is an urgent need in diagnosis and staging for reliable objective precursors and markers. Three-dimensional ultrahigh-resolution frequency domain optical coherence tomography (3D UHR OCT) holds particular promise in this respect since it enables volumetric assessment of intraretinal layers including tomographic data for the retinal nerve fiber layer (RNFL) and optic nerve head. The integrated analysis of this information and the resolution advantage has enabled the development of more informative indices of axonal damage in glaucoma compared with measurements of RNFL thickness and cup-to-disc ratio provided by commercial OCT devices. The potential for UHR OCT in enabling the combined analysis of tomographic and volumetric data on retinal structure is explored. A novel parameter was developed; the three-dimensional minimal distance as the optical correlate of true retinal nerve fiber layer thickness around the optic nerve head region. For the purposes of this pilot study, we present data from a normal subject and from two patients with characteristic optic nerve and retinal nerve fiber layer changes secondary to glaucoma.

Choroidal thinning in diabetes type 1 detected by 3-dimensional 1060 nm optical coherence tomography

PURPOSE

To map choroidal (ChT) and retinal thickness (RT) in patients with diabetes type 1 with and without maculopathy and retinopathy in order to compare them with healthy subjects using high speed 3-dimensional (3D) 1060 nm optical coherence tomography (OCT).

METHODS

Thirty-three eyes from 33 diabetes type 1 subjects (23-57 years, 15 male) divided into groups of without pathology (NDR) and with pathology (DR; including microaneurysms, exudates, clinically significant macular-oedema and proliferative retinopathy) were compared with 20 healthy axial eye length and age-matched subjects (24-57 years, 9 male), imaged by high speed (60.000 A-scans/s) 3D 1060 nm OCT performed over 36° × 36° field of view. Ocular health status, disease duration, body mass index, haemoglobin-A1c, and blood pressure (bp) measurements were recorded. Subfoveal ChT, and 2D topographic maps between retinal pigment epithelium and the choroidal/scleral-interface, were automatically generated and statistically analyzed.

RESULTS

Subfoveal ChT (mean ± SD, μm) for healthy eyes was 388 ± 109; significantly thicker than all diabetic groups, 291 ± 64 for NDR, and 303 ± 82 for DR (ANOVA P < 0.004, Tukey P = 0.01 for NDR and DR). Thinning did not relate to recorded factors (multi-regression analysis, P > 0.05). Compared with healthy eyes and the NDR, the averaged DR ChT-map demonstrated temporal thinning that extended superiorly and temporal-inferiorly (unpaired t-test, P < 0.05). Foveal RT and RT-maps showed no statistically significant difference between groups (mean SD, μm, healthy 212 ± 17, NDR 217 ± 15, DR 216 ± 27, ANOVA P > 0.05).

CONCLUSIONS

ChT is decreased in diabetes type 1, independent of the absence of pathology and of diabetic disease duration. In eyes with pathology, 3D 1060 nm OCT averaged maps showed an extension of the thinning area matching retinal lesions and suggesting its involvement on onset or progression of disease.

RNA editing of tRNA(Phe) and tRNA(Cys) in mitochondria of Oenothera berteriana is initiated in precursor molecules

We have analyzed the role of RNA editing in the correction of mismatched base pairs in tRNA secondary structures in mitochondria of the flowering plant Oenothera berteriana. Comparison of genomic and cDNA sequences from unprocessed primary transcripts of the newly characterized genes for tRNA(Cys), tRNA(Asn) and tRNA(Ile) and the previously described gene for tRNA(Phe) revealed single nucleotide discrepancies in the tRNA(Cys) and tRNA(Phe) sequences. While the change in the anticodon stem of tRNA(Cys) alters a C-T to a T-T mismatch, the nucleotide transition in the tRNA(Phe) restores a conventional T-A Watson-Crick base pair, replacing a C-A mismatch in the acceptor stem. Since both nucleotide alterations are conversions from genomic cytidines to thymidines in the cDNA (uridines in the tRNAs), they are attributed to RNA editing, which is observed in nearly all mRNAs from plant mitochondria.