[Loeys-Dietz syndrome (TGFßR2 mutation) in a 4-year-old child with thoracic aortic aneurysm]. / Syndrome de Loeys-Dietz (mutation TGFßR2) chez une enfant de 4ans avec anévrysme de l'aorte thoracique.

Loeys-Dietz syndrome is a rare form of connective tissue disorder, whose clinical features can resemble those of Marfan syndrome, but with a more unpolished appearance. Recently brought out, this pathology remains little known; however, its consequences may be dramatic. We report on the case of a 4-year-old girl followed for a congenital hip dislocation, in which a systematic exam found increased cutaneous elasticity and a bifid uvula, suggesting a connective tissue disorder. Symptoms were unpolished, as the child's height was normal, without any positive cardiac, rheumatological, or ophthalmological family history. Cardiovascular tests found a thoracic aortic aneurysm at the Valsalva sinus (26mm, Z-score=+4.24). A genetic investigation found a TGFßR2 gene mutation, leading to the diagnosis of Loeys-Dietz syndrome type 2. Skeletal damage associated with bifid uvula and/or hypertelorism and an aneurysm of the ascending aorta should guide the genetic investigation to the search for TGF-ß vasculopathy such as Loeys-Dietz syndrome.

London 2012: prescribing for athletes in ophthalmology.

AIMS: Prescribing for athletes requires an up-to-date knowledge of the World Anti-Doping Agency's list of prohibited substances. As the London 2012 Olympic Games attract athletes from around the world, we review the current guidelines with respect to all medications licensed for ophthalmic use in the United Kingdom. We describe the process that an ophthalmologist can use to check for permissible medications and also highlight treatments that are contraindicated. METHODS: We systematically reviewed all 77 drugs listed in Section 11 of the British National Formulary (Issue 63) for use in the treatment of ophthalmic conditions, and referenced these against the 2012 Prohibited List published by the World Anti-Doping Agency. RESULTS: The majority of ophthalmic preparations are suitable for use in- and out-of-competition. Some preparations, such as glucocorticoids, are prohibited when administered systemically but permitted for topical administration. Beta-blockers are prohibited in-competition and oral carbonic anhydrase inhibitors are prohibited in- and out-of competition. CONCLUSION: The 2012 Prohibited List has important implications for the pharmacological treatment of ophthalmic conditions in athletes. Clinicians prescribing for athletes have a duty to familiarize themselves with the list in order to avoid causing significant damage to their patient's career and reputation.

A randomised trial of bevacizumab and reduced light dose photodynamic therapy in age-related macular degeneration: the VIA study.

AIM: To determine if reduced light-dose photodynamic therapy (PDT) combined with bevacizumab will decrease the number of bevacizumab treatments required over 6 months compared with bevacizumab monotherapy in neovascular age-related macular degeneration (AMD). METHODS: Thirty-six patients with neovascular AMD were recruited for this randomised, double-masked, controlled clinical trial. Patients received intravitreal bevacizumab plus PDT using a light dose of either 25 J/cm2 (group 1) or 12 J/cm2 (group 2), or intravitreal bevacizumab plus sham PDT (group 3). Patients returned monthly for possible retreatment with bevacizumab or combination therapy (with a 3-month minimum interval between combination treatments); retreatment decisions were primarily based on optical coherence tomography. The main outcome measure was the mean number of bevacizumab treatments required over 6 months. RESULTS: Patients required a mean of 2.8 bevacizumab treatments in group 1 and 2.5 in group 2, compared with 5.1 in group 3 (p = 0.005 and p<0.001, respectively). CONCLUSIONS: Combination bevacizumab and 25 J/cm2 or 12 J/cm2 PDT significantly reduced the number of bevacizumab treatments required over 6 months. This study was powered to examine number of treatments, but not visual acuities. Nevertheless, visual acuities responded favourably in all three groups. Further studies will be helpful to explore visual outcomes.

Neovascular AMD: an overlooked risk factor for injurious falls.

UNLABELLED: While those with neovascular age-related macular degeneration (NV-AMD) may be at increased risk of injurious falls risk due to poor central vision and suboptimal responses when falling, preserved peripheral vision and decreased activity levels may actually be protective. Compared with control participants, patients with NV-AMD had a significantly greater number of falls and almost twice the risk of injurious falls. INTRODUCTION: Impaired vision, particularly peripheral visual function, is a key risk factor for injurious falls. NV-AMD is a leading cause of severely impaired vision among older adults but is associated with a profound central, rather than peripheral, deficit. The objective was to determine whether older women with NV-AMD are at an increased risk of falls or injurious falls. METHODS: We conducted a 12-month prospective cohort study of community-dwelling older (>or=70 years) women, enrolling 114 with NV-AMD and 132 without from a retinal clinic in Vancouver, Canada. Fall incidence was determined through monthly telephone follow-up, with fall severity classified by a blinded reviewer. We compared mean injurious falls per person-year between groups using negative binomial regression. RESULTS: A mean of 0.37 injurious falls per person-year were experienced among NV-AMD participants, compared to 0.16 injurious falls per person-year among non-NV-AMD participants (p = 0.006). The age-adjusted incidence rate ratio for injurious falls, for an individual with NV-AMD compared to without, was 1.77 (1.07-3.02). CONCLUSIONS: Older women with NV-AMD are at almost twice the risk of injurious falls compared to those without. Clinicians caring for older adults should recognise NV-AMD as an important risk factor for injurious falls.

Comparison of visual acuity outcomes in predominantly classic vs occult lesions in age-related macular degeneration treated with photodynamic therapy.

PURPOSE: To determine if patients with occult with no classic and predominantly classic (PC) choroidal neovascular membranes have clinically equivalent visual outcomes after treatment with photodynamic therapy (PDT) with verteporfin. METHODS: This is a retrospective, observational cohort study. Two hundred and seventy-seven consecutive patients with occult or PC choroidal neovascularization secondary to age-related macular degeneration treated with PDT were included. The main outcome was the difference in mean change in Early Treatment of Diabetic Retinopathy Study (ETDRS) acuity lost from baseline in occult vs PC lesions, with the minimal clinically important difference (MCID) set at 7.5 letters. RESULTS: At baseline, 131 patients had occult and 146 had PC choroidal neovascularization. Twelve-month follow-up data were available for 94 occult and 110 PC participants. Occult patients lost an average of 8.7 letters (1.9 lines), and patients in the PC group an average of 10.0 ETDRS letters (two lines) over 12 months. The mean letters lost at 12 months was not significantly different between the groups, and the MCID was not detected (difference=1.3 letters; P=0.411; 95% confidence interval (-2.3, 5.6)). Patients with occult lesions required a mean of 2.99 treatments vs a mean of 2.96 treatments in the PC group (out of a possible 4; P=0.172). CONCLUSION: We were not able to detect a clinically important difference in mean change in visual acuity with PDT treatment between patients with occult and PC lesions.

The role of leptin in choroidal neovascularization.

PURPOSE: The purpose of this study was to investigate the role of leptin in choroidal neovascularization. METHODS: We examined the localization of leptin by immunohistochemistry in nine choroidal neovascular membranes surgically excised from patients with age-related macular degeneration, idiopathic choroidal neovascularization, and ocular histoplasmosis. Controls included omission of primary antibody, use of an irrelevant primary antibody and leptin staining of posterior segment of four normal donor eyes. RESULTS: Leptin was present in eight membranes and appeared vesicular, within the cytoplasm. The more vascular membranes and those consisting of a larger number of retinal pigment epithelium cells were associated with greater leptin staining. Leptin was not seen in the posterior segment of the four normal eyes. CONCLUSION: We suggest that leptin plays an active role in choroidal neovascularization, although further experiments are necessary to establish a causal relationship.

Vitrectomy for pars planitis complicated by vitreous hemorrhage: visual outcome and long-term follow-up.

PURPOSE: To characterize the visual results of vitrectomy for nonclearing vitreous hemorrhage in pars planitis. METHODS: Case series. RESULTS: All six eyes (100%) had a visual acuity of 20/200 or less preoperatively. Postoperatively, five eyes (83%) improved to a final visual acuity of better than 20/30, and one eye improved to 20/100. The poorer vision of the latter patient was attributed to cystoid macular edema. Postoperative follow-up range was from 1.3 to 9 years (mean, 4.2 years). CONCLUSION: A substantial long-term benefit is seen in patients with pars planitis treated with vitrectomy for nonclearing vitreous hemorrhage. A larger case series will be needed to confirm whether such excellent outcomes can be expected.

Sildenafil-mediated reduction in retinal function in heterozygous mice lacking the gamma-subunit of phosphodiesterase.

PURPOSE: Retinitis pigmentosa (RP) is a common inherited degenerative retinal disease that has many causes including mutations in the genes coding for cyclic guanosine monophosphate (cGMP) phosphodiesterase 6 (PDE6). Sildenafil (Viagra; Pfizer Pharmaceuticals, New York, NY), a widely used medication for erectile dysfunction, is a specific inhibitor of PDE, with the potential to affect PDE6 in the retina. The purpose of this study was to investigate the retinal effects of sildenafil on knockout mice heterozygous for a mutation causing absence of the gamma subunit of rod PDE6 (PDEG:(tm1)/+). METHODS: Wild-type mice and PDEG:(tm1)/+ mice were subjected to electroretinography (ERG) 1 hour after exposure to one of three treatments: 1) no drug, 2) an intraperitoneal injection of sildenafil at 2 times the equivalent maximal daily recommended dosage for humans, or 3) 10 times this dosage. Control ERGs were also obtained to evaluate the reversibility of changes in retinal function after sildenafil treatment. A minimum of 48 hours elapsed between electroretinogram (ERG) recordings for drug washout and animal recovery. RESULTS: ERGs of the PDEG:(tm1)/+ mice treated with sildenafil showed a reversible, dose-dependent decrease in a- and b-wave amplitudes. Wild-type mice treated with sildenafil did not show significant differences in either a- or b-wave amplitudes compared with untreated control animals. CONCLUSIONS: These findings suggest that sildenafil has a significant impact on retinal function in PDEG:(tm1)/+ mice and may have implications in human carriers of RP. In addition, extension of these results in other model systems could be useful in understanding the mechanisms of RP and other forms of retinal degeneration.

The physical basis of nucleic acid base stacking in water.

It has been argued that the stacking of adenyl groups in water must be driven primarily by electrostatic interactions, based upon NMR data showing stacking for two adenyl groups joined by a 3-atom linker but not for two naphthyl groups joined by the same linker. In contrast, theoretical work has suggested that adenine stacking is driven primarily by nonelectrostatic forces, and that electrostatic interactions actually produce a net repulsion between adenines stacking in water. The present study provides evidence that the experimental data for the 3-atom-linked bis-adenyl and bis-naphthyl compounds are consistent with the theory indicating that nonelectrostatic interactions drive adenine stacking. First, a theoretical conformational analysis is found to reproduce the observed ranking of the stacking tendencies of the compounds studied experimentally. A geometric analysis identifies two possible reasons, other than stronger electrostatic interactions, why the 3-atom-linked bis-adenyl compounds should stack more than the bis-naphthyl compounds. First, stacked naphthyl groups tend to lie further apart than stacked adenyl groups, based upon both quantum calculations and crystal structures. This may prevent the bis-naphthyl compound from stacking as extensively as the bis-adenyl compound. Second, geometric analysis shows that more stacked conformations are sterically accessible to the bis-adenyl compound than to the bis-naphthyl compound because the linker is attached to the sides of the adenyl groups, but to the ends of the naphthyl groups. Finally, ab initio quantum mechanics calculations and energy decompositions for relevant conformations of adenine and naphthalene dimers support the view that stacking in these compounds is driven primarily by nonelectrostatic interactions. The present analysis illustrates the importance of considering all aspects of a molecular system when interpreting experimental data, and the value of computer models as an adjunct to chemical intuition.

Improvement in macular function after retinal translocation surgery in a patient with age-related macular degeneration.

PURPOSE: To assess focal electroretinographic findings before and after retinal translocation surgery in a patient with age-related macular degeneration. METHOD: Case report. A 79-year-old man with a well-defined subfoveal choroidal neovascular membrane from age-related macular degeneration underwent preoperative and postoperative focal electroretinography. RESULTS: After retinal translocation surgery, best-corrected Snellen visual acuity improved from 9/200 to 20/60. A significant increase in mean foveal amplitude, from 0.08 microV to 0.16 microV (P = 0.008) was recorded. CONCLUSION: Age-related macular degenerative changes in visual acuity and foveal electroretinogram amplitude may be reversible after retinal translocation surgery.

The nursing process in photodynamic therapy.

The results from the TAP Study have been found to be significant, but remember this is not a cure. There are no quick and easy solutions to this devastating disease, which can creep up so suddenly and without warning. Ophthalmologists may be able to stabilize the vision without allowing it to become worse, but the key words are "without allowing it to become worse." Unfortunately, to most patients, it is already worse. Nurses must address the patients' feelings and concerns first, before offering a physical solution that is only a temporary "band aid." After 10 years of working in the area of ophthalmology, specifically low vision, it has come to the authors' attention that a large percentage of patients suffering from AMD display depressive symptoms such as feelings of sadness, worthlessness, and hopelessness, and low self-esteem. Many appear to go through a grieving process. Keeping this is mind, the overall goal in nursing care should be to help patients with AMD use available resources so they have the potential to maintain a satisfying quality of life, physically and emotionally.

Clinical and immunocytochemical findings in a case of melanoma-associated retinopathy.

OBJECTIVE: To describe an unusual case of melanoma-associated retinopathy (MAR). DESIGN: Retrospective, observational case report and experimental study. PARTICIPANTS: A 61-year-old man with a history of cutaneous melanoma, acquired bilateral central scotomas, and night blindness. INTERVENTION: Serial full-field electroretinography (ERG) and Goldmann perimetry were performed. Serum was screened for cancer-associated retinopathy (CAR) antibodies by Western blotting. Sections of human and rat retina were examined by immunofluorescence microscopy to determine whether retinal cells were reactive with this patient's serum. A metastatic workup was performed. MAIN OUTCOME MEASURES: Electroretinography, Goldmann visual field testing, and immunocytochemistry were performed. RESULTS: The results were as follows: (1) The ERG showed a profound loss of the b-wave amplitude and a "negative" b-wave characteristic of congenital stationary night blindness; (2) a central scotoma and peripheral constriction were identified on Goldmann visual field tests; (3) as in other patients with MAR, bipolar cells in human and rat retinas were immunolabeled with this patient's serum; and (4) a previously unsuspected focus of metastatic melanoma was discovered. CONCLUSIONS: Recognition of this condition may help to identify an occult focus of metastatic melanoma.

Prophylactic scleral buckle for prevention of retinal detachment following vitrectomy for macular hole.

AIM: To review the rate of retinal detachment after macular hole surgery in patients who received vitrectomy and scleral buckle versus those who had vitrectomy alone. METHODS: All patient charts and hospital records were examined for patients who underwent vitrectomy surgery for macular hole between September 1993 and June 1997. A total of 326 patients were identified and all were followed for a minimum of 6 months. Clinical records were examined for details of the surgical procedure, visual acuity, hole closure status, adjuvant therapies used, and postoperative retinal attachment status. Relative risks (the ratio of the incidence rate in the exposed to that in the unexposed) with 95% confidence intervals and chi(2) tests were calculated to determine which variables were associated with retinal detachment. The primary outcome measure in this review was retinal attachment status. RESULTS: Of 326 eyes which underwent surgery for macular hole during the study period, scleral buckles were utilised in 152 (46.6%) patients. Analysis revealed a detachment rate of 13.2% in patients who did not receive a scleral buckle compared with 5.9% detachment rate in those who did. Analysis of these results indicated a 2.42 times greater risk of developing a retinal detachment in patients without a scleral buckle. Complications related to the use of scleral buckles occurred in two of 152 cases (1.3%) CONCLUSIONS: A reduction in the rate of retinal detachment was noted in patients receiving prophylactic scleral buckles. Those finding suggest a possible beneficial effect of this adjunctive procedure in preventing postoperative retinal detachments. The authors are currently preparing a multicentred, prospective, clinical trial to further study this hypothesis

Reduced Susceptibility of Brassica napus to Pratylenchus neglectus in Plants with Elevated Root Levels of 2-Phenylethyl Glucosinolate.

The effect of canola (Brassica napus) as a crop suppressive to Pratylenchus neglectus is in part due to the release of nematicidal isothiocyanates, particularly 2-phenylethyl isothiocyanate, from degrading root tissues. However, many cultivars of canola are relatively susceptible to P. neglectus and will fail to reduce soil populations of the nematode. A survey of B. napus accessions and closely related species revealed limited scope to decrease the susceptibility of canola through conventional intercrossing. Susceptibility to P. neglectus was not related to the total glucosinolate levels, but there were signifi- cant, negative correlations (r = -0.619, -0.517; P < 0.001) between root levels of 2-phenylethyl glucosinolate (isothiocyanate precursor) and plant susceptibility to P. neglectus: plants containing more than a certain threshold level of 2-phenylethyl glucosinolate showed reduced susceptibility to the nematode. Selection for high root levels of 2-phenylethyl glucosinolate should reduce the susceptibility of the plants during the growing season while also increasing the nematicidal impact of the degrading root tissues, thereby improving the suppressive benefits of the crop when used in rotation with cereals.

Electrostatic channeling in the bifunctional enzyme dihydrofolate reductase-thymidylate synthase.

The bifunctional enzyme dihydrofolate reductase-thymidylate synthase (DHFR-TS) carries out two distinct reactions, with the dihydrofolate produced by the TS-catalyzed reaction acting as the substrate for the DHFR-catalyzed reaction. Brownian dynamics simulation techniques were used to investigate the possible role of electrostatics in determining efficient channeling of the substrate, by explicitly simulating substrate diffusion between the two active sites. With a substrate charge of -2, almost all (> 95%) substrate molecules leaving the TS active site reached the DHFR active site at zero ionic strength. Under the same conditions, but in the absence of electrostatic effects, successful channeling was reduced to only around 6%: electrostatic effects therefore appear essential to explain the efficient channeling observed experimentally. The importance of substrate charge, the relative contributions of specific basic residues in the protein, the role played by the second monomer of the dimer in channeling and the effects of changing ionic strength were all investigated. Simulations performed for substrate transfer in the opposite direction suggest that channeling in DHFR-TS is not strongly directional and that the role of electrostatics is perhaps more one of restricting diffusion of the substrate than one of actively guiding it from the TS to the DHFR active site. The results demonstrate that electrostatic channeling can be a highly efficient means of transferring charged substrates between active sites in solvent-exposed environments.

Foot pathology in insulin dependent diabetes.

OBJECTIVES: Foot pathology is a major source of morbidity in adults with diabetes. The aim of this study was to determine if children with insulin dependent diabetes have an increased incidence of foot pathology compared with non-diabetic children. DESIGN: Questionnaire, clinical examination, and biomechanical assessment. SUBJECTS: 67 diabetic children and a comparison group matched for age, sex, and social class. RESULTS: We found significantly more foot pathology in the children with diabetes (52 children) than the comparison group (28 children); with more biomechanical anomalies (58 children with diabetes, 34 comparison group); and a higher incidence of abnormal skin conditions (53 children with diabetes, 27 comparison group). Forty two children with diabetes had received foot health education compared with 27 in the comparison group, but the study revealed ignorance and misconceptions among the diabetic group, and previous contact with a podiatrist was minimal. CONCLUSIONS: The survey suggests that children with diabetes have an increased incidence of foot pathology justifying greater input of podiatric care in the hope of preventing later problems.

Ring chromosome 21: characterization of DNA sequences at sites of breakage and reunion.

We have presented studies of an unusual child with an r21 chromosome who lacks the phenotype of Down syndrome. We have sequenced the region of the breakpoint in the normal DNA fragment and have isolated the abnormal breakpoint fragment as a 7.5-kb EcoRI fragment. We have preliminary evidence localizing the breakpoint to a few hundred base pairs of 21q DNA. Since the child lacks the classical phenotype of Down syndrome, further studies of the DNA distal to the breakpoint on the long arm of chromosome 21 may help us to elucidate "genes" important to the phenotype of Down syndrome.