Motif lengths of circular codes in coding sequences

Protein synthesis is a crucial process in any cell. Translation, in which mRNA is translated into proteins, can lead to several errors, notably frame shifts where the ribosome accidentally skips or re-reads one or more nucleotides. So-called circular codes are capable of discovering frame shifts and their codons can be found disproportionately often in coding sequences. Here, we analyzed motifs of circular codes, i.e. sequences only containing codons of circular codes, in biological and artificial sequences. The lengths of these motifs were compared to a statistical model in order to elucidate if coding sequences contain significantly longer motifs than non-coding sequences. Our findings show that coding sequences indeed show on average greater motif lengths than expected by chance. On the other hand, the motifs are too short for a possible frame shift recognition to take place within an entire coding sequence. This suggests that as much as circular codes might have been used in ancient life forms in order to prevent frame shift errors, it remains to be seen whether they are still functional in current organisms.

Mononuclear Phagocytes in Proliferative Vitreoretinopathy (PVR). A Specific Role of Microglial Cells in Non-Traumatic Disease?

Mononuclear phagocytes have been a focus of attention in the cellular biology of proliferative vitreoretinopathy (PVR) for more than ten years. The pattern of phagocyte participation in periretinal traction membrane formation in PVR depends on the etiology, i.e. trauma, rhegmatogenous retinal detachment, previous therapy, i.e. multiple surgical interventions, and the clinical stage of the disease. We have recently identified microglial cells as a distinct cellular population, in membranes from patients with non-traumatic PVR. Current evidence of mononuclear phagocyte function in PVR suggests a role for resident phagocytes of the vitreous and retina in PVR subsequent to rhegmatogenous detachment, and a role for blood-derived monocytes in post-traumatic PVR. The cellular biology of PVR may be much more heterogeneous than previously assumed.

Functional Results after Vitrectomy with Silicone Oil Injection

In a prospective study we investigated the visual acuity and differential light sensitivity in 39 patients (40 eyes) with reattached macula. One group, treated with an encircling band (21 eyes), was compared to another, where vitrectomy and silicone oil injection had been necessary (19 eyes). Intraoperatively 9 of the vitrectomized eyes received an infusion of daunomycin (7.5 mg/l for 10 min). On average the vitrectomized eyes had a greater loss of visual acuity and differential light sensitivity. In all groups we found a positive correlation between visual acuity and the differential light sensitivity. At the same visual acuity we did not find any obvious difference in sensitivity between the groups. Correlation and regression line were similar for both groups. The mean relative sensitivity was lower in the fovea than in the rest of the tested field. A selective effect of silicone oil on either spatial resolution or differential light sensitivity could not be verified. The intraoperative application of daunomycin had no influence on the functional results.

Thrombospondin: A New Attachment Protein in Preretinal Traction Membranes

Thrombospondin (TSP), an adhesive integrin-binding protein of plasma and platelets, was detected in preretinal traction membranes from patients with idiopathic (8/8) and traumatic (7/8) proliferative vitreoretinopathy (PVR) and proliferative diabetic retinopathy (PDR) (6/8). TSP immunoreactivity was compared to the pattern of von Willebrand factor, plasma transglutaminase (blood coagulation factor XIII), fibronectin, and mononuclear phagocytes, using double-label immunoflurorescence microscopy. TSP was partially colocalised with the endothelial cell marker, von Willebrand factor, in PDR. The codistribution of catalytic factor XIII and two cross-linking substrates, fibronectin and TSP, suggests a functional role of the enzyme in the extracellular matrix build-up in PVR and PDR. No significant TSP synthesis by mononuclear phagocytes was observed. Western blotting indicated a plasmin-mediated intravitreal breakdown of presumably plasmatic TSP in PVR and PDR.

Surgical Workflow Management Schemata for Cataract Procedures

Objective: Workflow guidance of surgical activities is a challenging task. Because of variations in patient properties and applied surgical techniques, surgical processes have a high variability. The objective of this study was the design and implementation of a surgical workflow management system (SWFMS) that can provide a robust guidance for surgical activities. We investigated how many surgical process models are needed to develop a SWFMS that can guide cataract surgeries robustly.

Methods: We used 100 cases of cataract surgeries and acquired patient-individual surgical process models (iSPMs) from them. Of these, randomized subsets iSPMs were selected as learning sets to create a generic surgical process model (gSPM). These gSPMs were mapped onto workflow nets as work-flow schemata to define the behavior of the SWFMS. Finally, 10 iSPMs from the disjoint set were simulated to validate the workflow schema for the surgical processes. The measurement was the successful guidance of an iSPM.

Results: We demonstrated that a SWFMS with a workflow schema that was generated from a subset of 10 iSPMs is sufficient to guide approximately 65% of all surgical processes in the total set, and that a subset of 50 iSPMs is sufficient to guide approx. 80% of all processes.

Conclusion: We designed a SWFMS that is able to guide surgical activities on a detailed level. The study demonstrated that the high inter-patient variability of surgical processes can be considered by our approach.

[Diagnostic Approaches to Suspected Choroidal Melanoma]

Whenever funduscopy reveals possible choroidal melanoma, all available information must be gathered to either confirm or exclude the diagnosis. Well-defined funduscopic criteria are available, which can already lead to a high degree of diagnostic certainty. Additional technical examinations can be used to exclude possible differential diagnoses. In cases where no clear diagnosis can be established, it is possible to take a biopsy or to watch and wait in order to observe possible growth. Whenever the diagnosis of a choroidal melanoma is established, cancer staging has to be performed in order to search for possible metastases.

[Bilateral eye injuries by external transversal force]

A 49-year-old female victim of violent crime with an acute bilateral loss of vision was referred to our hospital. The ophthalmological evaluation showed complete subconjunctival hemorrhage of both eyes, bilateral hemophthalmos and hypotonia of the left eye. These raised the suspicion of an occult scleral rupture. We immediately performed exploratory surgery and found a perforating scleral lesion of the left eye and a penetrating scleral lesion of the right eye. Furthermore, a small, cruciform wound was detected on the left temple. In cooperation with the department of radiology, the extraordinary injury pattern was reconstructed: a horizontal stab wound with perforation of the left eye and penetration of the right eye caused by a screwdriver. Visual rehabilitation necessitated further surgical interventions. Besides the intraoperative approach, immediate primary wound management within 100 h of trauma plays a pivotal role for long-term outcome.

[Proliferative Vitreoretinopathy]

Proliferative vitreoretinal retinopathy (PVR) is a very severe complication of vitreoretinal surgery. PVR is characterised by a complex cellular reaction. This corresponds to a vitreoretinal wound healing reaction and leads to tractional retinal detachment fixed by membranes. A rational goal of treatment is the removal of active cells and membranes, particularly the whole vitreous body; this can only be achieved surgically.

[Triple Descemet membrane endothelial keratoplasty. Indications, variations and results]

When Descemet membrane endothelial keratoplasty (DMEK) is indicated in patients with phakic eyes, a combination with phacoemulsification and intraocular lens implantation in one sitting should be considered as a triple DMEK. The best possible preoperative deswelling of the cornea should be strived for in order to allow sufficient viewing conditions for the individual stages of cataract surgery. Furthermore, technical details, e.g. regulation of pupillary width also must be considered. The power of the intraocular lens has to be adjusted in order to compensate for the shift of refraction towards hyperopic values induced by DMEK surgery. A rapid and clear improvement in visual acuity can normally be achieved after a triple DMEK. There seem to be no disadvantages compared with a two-stage procedure for DMEK and cataract surgery.

[Refractive changes in triple Descemet membrane endothelial keratoplasty]

BACKGROUND

A hyperopic shift, i.e. a shift of refraction in the direction of plus values, in Descemet membrane endothelial keratoplasty (DMEK) is a well-known phenomenon. Because of the need to select an appropriate intraocular lens power this becomes particularly relevant in triple DMEK, which is a combination of DMEK and cataract surgery.

OBJECTIVES

In this study the refractive changes induced by triple DMEK were evaluated. The underlying mechanisms were classified based on corneal topographical data.

MATERIAL AND METHODS

The study involved a retrospective evaluation of 29 eyes from 26 patients who underwent triple DMEK. The preoperative and postoperative refractions were compared with the initially desired target refraction. Calculations concerning refractive power were performed using corneal topographical data and the Gullstrand formula.

RESULTS

On average a hyperopic shift was observed. The operation led to steepening of the posterior corneal surface and flattening of the anterior corneal surface. Both resulted in a reduction of corneal refractive power but changes of the posterior corneal surface were identified as the most important factor. Those patients in whom both eyes had been operated on, showed very similar postoperative topography for both eyes, irrespective of the preoperative values.

CONCLUSION

The observed hyperopic shift was a mean value. A prediction of refraction in the individual cases by means of the available parameters was not possible. In general, the selection of an intraocular lens with a stronger myopic target refraction than that for standard cataract surgery is recommended.

Anterior Chamber Live Loa loa: Case Report

We reported a case of unusual intraocular Loa loa in a 27-year-old patient who presented with painful red eye. Biomicroscopy revealed a living and active adult worm in the anterior chamber of the right eye. After surgical extraction under local anesthesia, parasitological identification confirmed L. loa filariasis.

[Unilateral Ranibizumab Treatment and Reduction of Macular Edema in the Contralateral Eye. Medication Effect or Natural Course?]

BACKGROUND

During unilateral treatment with ranibizumab, a reduction in the retinal thickness in the non-treated eye is occasionally observed. This may be due to the natural progression of the condition. It could also be the consequence of systemic absorption of intravitreal injections, leading to effects in the contralateral eye.

PATIENTS

We describe 40 patients with either exsudative age-related macular degeneration (AMD) or diabetic macular oedema (DME). During treatment with ranibizumab, a reduction in retinal thickness in the contralateral eye was observed in this group (observation group). Another 40 AMD or diabetes patients under treatment with ranibizumab were selected as control group. These patients showed retinal swelling in the contralateral eye, which remained stable or increased.

RESULTS

In the observation group, 58 % of the patients had a DME and 42 % had an AMD; in the control group, 25 % of the patients had a DME and 75 % of the patients had an AMD (p = 0.003). Retinal thickness before injection was 519 ± 126 µm in the observation group and 432 ± 87 µm in the control group (p = 0.003). Retinal thickness in the contralateral eye was then 511 ± 162 µm in the observation group and 436 ± 149 µm in the control group (p = 0.036). The reduction in retinal thickness in the injected eye was 214 ± 144 µm in the observation group and 150 ± 89 µm in the control group (p = 0.06).

CONCLUSION

In the group of patients that showed reduction in retinal thickness under ranibizumab in the contralateral eye, there were more diabetes patients than in the comparable control group. Even before injection, these patients showed higher retinal thickness in both eyes than did those in the control group. Further prospective studies would be required to confirm a possible causal connection between ranibizumab injection and reduction in DME in the contralateral eye.

[Firework-related eye trauma from 2005 to 2013]

PURPOSE

Fireworks combusted during New Year's Eve festivities can cause different eye traumas which often need complex reconstructive surgery. It was our aim to systematically analyse these eye trauma cases which were treated at our clinic during the last eight years.

MATERIALS AND METHODS

Age, gender, side, trauma mechanism, treatment methods and outcome were analysed for all eye trauma cases caused by fireworks during the New Year's Eve celebrations from 2006 to 2013. For statistical analysis all trauma cases were divided into two groups of major and non-major eye trauma.

RESULTS

The total number of patients treated was 122 (28 women, 94 men, mean age 26.2±13.0 years) with 137 traumatised eyes (77 right, 60 left). 24.6% of patients were ≤18 years of age. 76.2% were bystanders. 50 eyes from 46 patients (37.7%) suffered from major eye trauma. 26 patients (21.3%) were hospitalised. 8 eyes (5.8%) suffered from a penetrating injury or globe rupture and underwent primary reconstructive surgery. Further 16 eyes (11.7%) suffered from major eye trauma without open globe injury. In the aftermath 11 eyes (8.0%) went blind (visual acuity<1/50). Gender, side and role of the patient were not significantly different between the two groups. Mean age was significantly higher in the major eye trauma group (p=0.01).

CONCLUSION

Young male bystanders have a high risk for suffering from eye trauma caused by fireworks. However older patients suffer from major eye trauma more often. More education and prophylaxis of eye trauma caused by fireworks is desirable.

[Scheimpflug photography of acute angle closure]

PURPOSE

In acute angle-closure glaucoma a laser iridotomy (IO) is performed to balance the intraocular pressure between the anterior and posterior chambers. The changes induced in the anterior chamber architecture were analyzed using Scheimpflug photography.

MATERIAL AND METHODS

Scheimpflug photography was performed in eyes with acute angle closure and in the contralateral eyes before and after IO.

RESULTS

In a group of 10 patients (8♀, 2♂, average age71.2 ± 5.3 years) 10 eyes with acute angle closure and 10 contralateral eyes were analyzed. The anterior chamber depth, central corneal thickness and anterior chamber angle did not change significantly after IO. The mean anterior chamber volume showed a statistically significant increase in the 10 eyes with acute angle closure and in the 10 contralateral eyes.

CONCLUSION

Anterior chamber volume increases due to IO but not anterior chamber depth, central corneal thickness and anterior chamber angle in eyes with acute angle closure.

Retinal vein thrombosis: pathogenesis and management

Retinal vein occlusion (RVO) is the most common retinal vascular disease after diabetic retinopathy. Owing to its multifactorial nature, however, management of this condition remains a challenge. Of the two main types of RVO, branch retinal vein occlusion (BRVO) is more prevalent than central retinal vein occlusion (CRVO). Most patients develop the disease at an elderly age, and more than half of them have associated systemic disorders (e.g. hypertension, hyperlipidemia and/or diabetes mellitus). There is no evidence to suggest routine testing for heritable thrombophilias in patients with RVO. The main cause of the visual impairment is macular edema, while neovascularization of the retina and optic disc are the most serious complications leading to vitreous hemorrhage, retinal detachment and neovascular glaucoma. Macular grid laser photocoagulation is an effective treatment for macular edema in patients with BRVO and a visual acuity of 20/40 or less. Other treatment options for reducing the edema are intravitreal steroids, anti-VEGF drugs and vitrectomy. The recently introduced intravitreal application of steroids and anti-VEGF drugs may prove to be a better approach for improving visual acuity. Finally, scatter panretinal laserphotocoagulation can effectively treat neovascularization and its secondary complications.

[UV risk perception by the general public: results of a representative questionnaire in Germany]

AIM OF THE STUDY

For public health promotion purposes it is important to know how the general public perceives the risk factor "UV exposure" and how UV risk perception is connected to health-related attitudes and beliefs. The aim of the study was to collect representative data about UV risk perception in Germany.

METHODS

A representative telephone survey using the ADM design was carried out among 1 501 German residents between May and July 2007. Variables related to UV risk knowledge, relevance of risk topics in every-day thinking and risk estimates were investigated. Data regarding a subjective benefit evaluation of UV exposition was also collected.

RESULTS

The results suggest no essential gaps in the general knowledge about UV risks, except for the underestimation of UV-related cataracts. The respondents thought it extremely likely that UV exposure would cause health damage such as skin cancer, photoaging or sun burns. People were asked to report how often they had thought about a number of health risks including UV risks in the last two weeks. It was established that UV risks are present but not dominant in people's every-day thinking. Along with it, the risk evaluation proves to be rather moderate. The mean value for respondents' perceived personal risk is M=5.1, in the midsection of the given 10-point scale. The results show that perceived personal risk is not influenced by the serious UV health risks such as cancer or cataracts. The results also indicate that UV benefit and UV risk perception are not strongly related to one another.

CONCLUSIONS

In summary, participants' perception and assessment of the various health risks of UV exposure seem to be realistic, but the UV risk assessment it is not related to the perception of personal risk. One must therefore assume that UV health risk information and education campaigns do not necessarily lead to a change in the perception of personal UV risk. Rather than addressing primarily risk knowledge, UV risk communication should focus more on motivational aspects and consider the role of UV benefit perception.

[Lutein and antioxidants in the prevention of age-related macular degeneration]

Demographic developments in Europe and North America are causing an increase of age-related diseases. Age-related macular degeneration (AMD) is one of the leading causes of severe central visual acuity loss in elderly people and seems to be an economic problem, too. There is evidence that oxidative damage is an important factor for exacerbation of AMD. Macular pigment with its antioxidative effect may serve as"natural sunglasses" filtering the blue light acting as a possible source of photooxidative damage to the neurosensory retina. The macular pigment consists mostly of lutein and zeaxanthin. These micronutrients from the group of carotenoids, as is the case for vitamins (vitamins C, E, and beta-carotene), cannot be synthesized in mammals and that is the reason why the role of micronutrition or its supplementation and its correlation to AMD progression has been discussed for years. The results of currently published studies are often contradictory. At present there are no results from randomized controlled studies confirming that supplementation of lutein and zeaxanthin can reduce the risk for AMD. Several epidemiological studies investigating the impact of antioxidants and omega-3 fatty acids on the incidence of AMD provided conflicting results.Up to now, AREDS is the largest randomized controlled study investigating the effect of supplementation of antioxidants, zinc, and copper on the progression of AMD. AREDS showed a significant effect of this supplementation in some particular groups of patients with AMD. The supplementation of lutein and omega-3 fatty acids is not toxic but a positive effect has not been proven by randomized studies.

[Primary vitrectomy with intraocular antibiotic application in postoperative endophthalmitis]

PURPOSE

Pars plana vitrectomy with intravitreal antibiotic application is an established procedure for treating postoperative endophthalmitis. The presented study analyzes our own results with this treatment as well as the role of adjuvant systemic steroid treatment.

METHOD

We analyzed the data of 34 consecutive patients with postoperative endophthalmitis from January 2000 to March 2006. Thirty-two patients underwent vitrectomy and intravitreal application of antibiotics, and two patients received intravitreal antibiotics only. All patients received intravitreal dexamethasone and systemic antibiotics, and 12 patients received the systemic treatment with prednisolone. The effect of vitrectomy with respect to final visual acuity and the rate of postoperative complications were analyzed. The vitreous was microbiologically examined. Postoperative follow-up time ranged from 2 weeks to 24 months.

RESULTS

Endophthalmitis followed cataract surgery with intraocular lens implantation in 30 patients (89%) and followed pars plana vitrectomy in four patients (11%). Positive cultures were obtained in 19 (56%) patients. Visual acuity improved in 31 (91%) patients. At their final examinations, 27 (79%) patients had gained visual acuity of 0.05 or better.

CONCLUSIONS

CONCLUSION

Immediate vitrectomy in combination with intraocular antibiotics and steroid administration resulted in preservation of ambulatory vision in most of the patients. Systemic postoperative therapy with steroids seems to be associated with better final visual acuity.