Comparative study of long-term outcomes of accelerated and conventional collagen crosslinking for progressive keratoconus.

PurposeTo compare the long-term outcomes of accelerated corneal collagen crosslinking (CXL) to conventional CXL for progressive keratoconus.Patients and methodsComparative clinical study of consecutive progressive keratoconic eyes that underwent either accelerated CXL (9 mW/cm2 ultraviolet A (UVA) light irradiance for 10 min) or conventional CXL (3 mW/cm2 UVA light irradiance for 30 min). Eyes with minimum 12 months' follow-up were included. Post-procedure changes in keratometry readings (Flat meridian: K1; steep meridian: K2), central corneal thickness (CCT), best spectacle-corrected visual acuity (BSCVA), and manifest refraction spherical equivalent (MRSE) were analysed.ResultsA total of 42 eyes were included. In all, 21 eyes had accelerated CXL (20.5±5.5 months' follow-up) and 21 eyes had conventional CXL group (20.2±5.6 months' follow-up). In the accelerated CXL group, a significant reduction in K2 (P=0.02), however no significant change in K1 (P=0.35) and CCT (P=0.62) was noted. In the conventional CXL group, a significant reduction was seen in K1 (P=0.01) and K2 (P=0.04), but not in CCT (P=0.95). Although both groups exhibited significant reductions in K2 readings, no noteworthy differences were noted between them (P=0.36). Improvements in BSCVA (accelerated CXL; P=0.22 and conventional CXL; P=0.20) and MRSE (accelerated CXL; P=0.97 and conventional CXL; P=0.54) were noted, however were not significant in either group.ConclusionAccelerated and conventional CXL appear to be effective procedures for stabilising progressive keratoconus in the long-term.

Insulin resistance correlates with maculopathy and severity of retinopathy in young adults with Type 1 Diabetes Mellitus.

AIMS: To assess the relationship between insulin resistance (IR), retinopathy and maculopathy in young adults with Type 1 diabetes mellitus. METHODS: A cross-sectional study at a regional Australian tertiary hospital. Retinal pathology, assessed by colour fundus photography, was correlated with two surrogate measures of IR: estimated Glucose Disposal Rate (eGDR) and Insulin Sensitivity Score (ISS), where lower scores reflect greater IR. RESULTS: 107 patients were recruited, with mean age 24.7years, 53% male, and mean duration of disease 10.8years. Mean eGDR scores (5.6vs 8.0 p<0.001) and ISS (4.7vs 7.9, p<0.001) were lower in subjects having at least moderate non-proliferative diabetic retinopathy (NPDR; relative to nil/mild-NPDR). Similarly, mean eGDR (4.2vs 6.2, p=0.001) and ISS (3.8vs 6.1, p=0.003) were lower in patients with maculopathy. Multivariate logistic regression modelling was used to control for confounding. For retinopathy severity, a unit increase in eGDR or ISS (representing lower IR) was associated with a 50% decrease in odds of moderate-NPDR or worse (eGDR OR 0.5, 95%CI 0.32-0.77, p=0.002; ISS OR 0.49, 95%CI 0.29-0.84, p=0.01). A unit increase in eGDR or ISS was associated with a 46-56% decrease in odds of maculopathy (eGDR OR 0.54, 95%CI 0.37-0.81, p=0.003; ISS OR 0.44, 95%CI 0.22-0.88, p=0.02). CONCLUSIONS: IR correlates with more severe retinopathy in young adults with Type 1DM. This is the first description of a correlation between IR and maculopathy in Type 1DM, warranting further evaluation. Prospective studies examining whether reducing IR can improve microvascular complications are required.

Middle cerebral artery to umbilical artery resistance index ratio in the prediction of neonatal outcome.

OBJECTIVE: The objectives of this study were to evaluate the usefulness of the middle cerebral artery to umbilical artery resistance index ratio (C/U ratio) as a predictor of adverse perinatal outcome, and to show that the absence of fetal umbilical artery end-diastolic velocity (AEDV) in SGA fetuses is associated with high morbidity and mortality. METHOD: In this prospective study, color Doppler flow imaging was used for the estimation of the C/U ratio in fetuses that were small for their gestational age, in 70 singleton pregnancies between 29 and 42 weeks of gestation. The subjects were categorized into two groups, with Group A consisting of 35 small for gestational age (SGA) fetuses with a normal C/U ratio (1.05 or higher), and Group B comprising 35 SGA fetuses with an abnormal C/U ratio (below 1.05). RESULT: The mean C/U ratio values for birth weight and gestational age were higher in group A than in group B. Fetuses born to mothers in group B stayed longer in the neonatal special care unit (NSCU), whereas the period from ultrasound examination to delivery was higher in the cases in group A. A higher percentage of mothers with an abnormal C/U ratio underwent cesarean section. Fetuses with an absent end-diastolic velocity of the umbilical artery had a higher morbidity. Three stillbirths occurred in fetuses with an absent end-diastolic velocity of the umbilical artery. CONCLUSION: Our results suggest that the C/U ratio is a good predictor of neonatal outcome, and could be used to identify fetuses at risk of morbidity and mortality. Fetal umbilical artery AEDV with intrauterine growth restriction is associated with high perinatal morbidity and mortality.

Plant vascular architecture and within-plant spatial patterns in resource quality following herbivory.

In this study, we used plant vascular architecture as a framework from which to predict induced changes in resource quality for Lema trilinea feeding on the host plant Solanum dulcamara at both low and high levels of herbivory. The systemic patterns of allocation of dye from a capillary tube inserted onto the petiole of the first true leaf and sections of the stem were used to establish the degree of vascular connectivity among different leaf positions. Induced changes in the activity of two defensive proteins, proteinase inhibitor (PI) and polyphenol oxidase (PPO), as well as larval L. trilinea performance, were measured in weakly or strongly connected leaves on plants with the first leaf damaged or undamaged by adult L. trilinea. At high levels of herbivory, larval performance decreased on the sixth leaf, which has strong vascular connections to the first leaf, yet increased on the fifth leaf, which has weak vascular connections to the first leaf. PPO activity increased in both the fifth and sixth leaf, while PI activity decreased in the fifth leaf although remaining unchanged in the sixth leaf. At low levels of herbivory, a decrease in larval performance was observed in the sixth leaf, but no change occurred in the weakly connected fifth leaf. Hence, plant vascular architecture clearly predicted within-plant changes in resource quality following only small amounts of herbivore damage.