Lower urinary cotinine level is associated with a trend toward more myopic refractive errors in Korean adolescents.

PurposeTo investigate the association between urinary cotinine levels as an objective biological marker for exposure to nicotine and refractive status.Patients and methodsThis cross-sectional study analyzed data from the Korea National Health and Nutrition Examination Survey between 2008 and 2011. A total of 1139 Korean adolescents aged 12-18 years were enrolled. Urinary cotinine concentrations and other potential risk factors for myopia were examined. Correlation analyses and multivariate regression analysis were performed to investigate the association between urinary cotinine level and refractive error.ResultsSpherical equivalent correlated significantly with urinary cotinine concentration (r=0.104, P=0.011). Lower urinary cotinine level was associated with a trend toward more myopic refractive errors (P for trend=0.003). After adjusting for age, sex, area of residence, physical activity, serum 25-hydroxyvitamin D level, parental income level, and receipt of basic livelihood security, subjects with a low urinary cotinine level had a significantly increased risk of myopia <-0.5 D (odds ratio (OR) 1.95, 95% confidence interval (CI) 1.18-3.21), <-3.0 D (OR 2.03, 95% CI 1.29-3.2), and <-6.0 D (OR 2.2, 95% CI, 1.15-4.23) when compared with subjects with a high urinary cotinine level. As urinary cotinine level decreased, the risks of myopia <-0.5 D, <-3.0 D, and <-6.0 D increased significantly (P for trend <0.05).ConclusionA trend toward less myopic refractive error was observed among Korean adolescents with higher urinary cotinine levels. This result provides the epidemiologic evidence implying nicotine as a potential modulator related with refractive development. Further studies with full consideration for myopia-associated risk factors are required to yield clear answers on the direct effect of smoking to the refractive status.

In-depth phenotyping of a Donnai-Barrow patient helps clarify proximal tubule dysfunction.

BACKGROUND: The megalin/cubilin/amnionless complex is essential for albumin and low molecular weight (LMW) protein reabsorption by renal proximal tubules (PT). Mutations of the LRP2 gene encoding megalin cause autosomal recessive Donnai-Barrow/facio-oculo-acoustico-renal syndrome (DB/FOAR), which is characterized by LMW proteinuria. The pathophysiology of DB/FOAR-associated PT dysfunction remains unclear. CLINICAL CASE: A 3-year-old girl presented with growth retardation and proteinuria. Clinical examination was unremarkable, except for a still-opened anterior fontanel and myopia. Psychomotor development was delayed. At 6, she developed sensorineural hearing loss. Hypertelorism was noted when she turned 12. Blood analyses, including renal function parameters, were normal. Urine sediment was bland. Proteinuria was significant and included albumin and LMW proteins. Immunoblotting analyses detected cubilin and type 3 carbonic anhydrase (CA3) in the urine. Renal ultrasound was unremarkable. Optical examination of a renal biopsy did not disclose any tubular or glomerular abnormality. Electron microscopy revealed that PT apical endocytic apparatus was significantly less developed. Immunostaining for megalin showed a faint signal in PT cytosol contrasting with the distribution of cubilin at the apical membrane. The diagnostic procedure led to identifying two mutations of the LRP2 gene. CONCLUSIONS: The functional loss of megalin in DB/FOAR causes PT dysfunction characterized by increased urinary shedding of CA3 and cubilin.

Passive smoking exposure might be associated with hypermetropia.

PURPOSE: The aim of the study was to explore the relationship between nicotine exposure in children via passive smoking and the refractive errors of these children. METHODS: The study included 300 children between the age of 5 and 12 years. Children were subjected to detailed history taking with special emphasis on the degree of exposure to passive smoke. They underwent a complete ophthalmological evaluation including cycloplegic refraction. Urine samples were collected to measure urinary levels of cotinine and creatinine with subsequent calculation of the cotinine creatinine ratio (CCR). RESULTS: The refractive error assessment indicated 122 hypermetropic (40.7%), 86 myopic (28.7%) and 92 emmetropic (30.7%) children. Gender and age were not statistically different between the three groups. Urinary cotinine was significantly higher in the hypermetropic than myopic and emmetropic groups (p < 0.0001). Moreover, it was significantly higher in the emmetropic group than the myopic one (p = 0.02). Cotinine/creatinine ratio (CCR) and the parental number of cigarettes smoked per day showed the same pattern as urinary cotinine. Considering all 300 data, the spherical equivalent refractive error was significantly correlated with the number of cigarettes smoked by the parents, CCR and urinary cotinine levels cotinine (p < 0.0001 for all correlations). CONCLUSION: Passive smoking indices were related to the degree of refractive error and children with hypermetropia showed significantly higher passive smoking indices. We suggest that passive smoking might be associated with a refractive error shift towards hypermetropia.

Myopia and plasma cortisol.

Estimation of plasma cortisol by fluorometric technique desorbed by Mallingly's was carried out in 56 cases, including 38 cases of myopia (19 cases of simple myopia and 19 cases of degenerative myopia) and 18 normal individuals. Urinary 17-keto steroids/24 hours was also estimated by Zimmermann technique in 12 out of the 56 cases, which include 8 cases of myopia (4 cases of simple myopia and 4 cases of degenerative myopia) and 4 normal individuals as control. Plasma cortisol level is lower in simple and degenerative myopia than in normal subjects, but on statistical analysis the difference was not of much significance. Patients with simple myopia with positive family history showed lower value of plasma cortisol than patients with simple myopia with negative family history, the difference was also statistically insignificant (P-0.1). In degenerative myopia patients, with and without family history, there was very little difference in plasma cortisol level and statistically highly insignificant (P-0.8). Urinary 17 keto steroid/24 hour values are lower in simple and degenerative myopia than in normal subjects.

[Some metabolic values of acid mucopolysaccharides in myopia (author's transl)]. / Einige Stoffwechselwerte für saure Mukopolysaccharide bei der Myopie

The study group consisted of 82 children aged 9 to 14 years with the following forms of myopia: progressive (37 cases), stable (22 cases), congenital stable (11 cases) and incipient (12 cases). During the period of progression in myopia, a significant increase was found in the 24-hour-excretion of acid mucopolysaccharides. In the patients with stable and congenital stable forms the excretion of acid mucopolysaccharides did not differ significantly from that in the control group of emmetropic and hypermetropic children. The results of electrophoresis on cellulose acetate and of the carbazol and orcinol reactions showed predominant excretion of A and C chondroitinsulphates in patients with myopia.

Stickler's syndrome (hereditary progressive arthro-ophthalmopathy).

The clinical features of Stickler's syndrome are described in two families with a total of 22 affected members and compared with those of the three previously reported families. Progressive joint degeneration (85%), myopia (83%) and retinal detachment (61%) are the most frequent manifestations. Cleft palate (28%), micrognathia (17%) and sensorineural hearing loss (9%) are also liable to occur in affected individuals. Inheritance is autosomal dominant with virtually complete penetrance. Genetic counselling is extremely important and relatively straightforward since most of the findings are manifest in the first two decades of life and represent severe incapacities to the affected families. All six of the affected individuals tested had increased urinary hydroxyproline excretion, a feature that may lead to earlier postnatal and possibly prenatal diagnosis.