Intravitreal bevacizumab to treat retinopathy of prematurity in 865 eyes: a study to determine predictors of primary treatment failure and recurrence.

PURPOSE: This study aimed to evaluate the rate and risk factors for primary failure and recurrence after intravitreal anti-VEGF injection in retinopathy of prematurity (ROP). METHODS: This retrospective study was performed on 865 eyes from 441 patients with retinopathy of prematurity receiving intravitreal bevacizumab from 2012 to 2019. Medical records of patients were evaluated. RESULTS: Mean gestational age (GA) and birth weight of patients were 28 ± 2 weeks and 1121 ± 312 g, respectively. Thirty-five eyes (4.04%) had a primary failure, including 18 eyes from 187 eyes in zone 1 (9.6%) and 17 eyes from 678 eyes in zone 2 (2.5%). The mean time of retreatment was 16.64 ± 13.68 days in eyes without regression ROP. The remaining 830 eyes (95.95%) were included in recurrence analysis. The recurrence occurred in 33 eyes (3.97%) of them in 20 patients, with the meantime of 77.52 days after the first treatment (IVB). The presence of plus disease, history of oxygen therapy or phototherapy, and GA less than 32 were associated with significantly increased prevalence of treatment failure. The risk factors predicting recurrence are lower birth weight, zone 1 pretreatment, history of intubation, anemia, and sepsis. CONCLUSION: Intravitreal anti-VEGF is a successful treatment for ROP with a low rate of primary failure and recurrence. Awareness of risk factors for treatment failure and recurrence may help clinicians to schedule more vigilant approach in susceptible cases.

Effects of extremely low frequency electromagnetic field (50 Hz) on pentylenetetrazol-induced seizures in mice.

The electromagnetic fields (EMF) have various behavioral and biological effects on human body. There are growing concerns about the consequences of exposure to EMF. However, some studies have shown beneficial effects of these waves on human. In this paper, we study the effect of acute, sub acute and long-term exposure to 50 Hz, 0.1 mT magnetic fields (MF) on the seizure induction threshold in mice. 64 mice are used and divided into four groups. Eight mice in any group were selected to be exposed to MF for specific duration and the others were used as a control group. The duration of the applied exposures was as follows: (1) 1 day (acute), (2) 3 days (sub acute), (3) 2 weeks (sub acute), (4) 1 month (long term). The mice were exposed 2 h for a day. After exposure, the pentylentetrazol (PTZ) is injected to the mice to induce seizure and the needed dose for the seizure induction threshold is measured. In the acute exposure, the threshold to induce seizure in the exposed and sham-exposed groups was 44.25 and 46.5 mg, respectively, while the difference was not significant (p value = 0.5). In the sub acute exposure (3 days), the mean amount of drug to induce seizure was 47.38 mg in the exposed and 43.88 mg in the sham-exposed groups, however, the difference was not significant (p value = 0.3). The results were 52.38 and 46.75 mg after 2 weeks of exposure which were not significantly different either (p value = 0.2). After 1 month of exposure to MF, the threshold for the induction of seizure was significantly increased (p value < 0.05). The mean dosage to induce seizure in the exposed and control group was 54.3 and 45.75 mg, respectively. However, considering the p value, the difference in the seizure induction threshold between the exposed and sham-exposed groups after acute and sub acute exposure was not significant, analyzing the effects of acute, sub acute and long-term exposures totally indicates that increasing the exposure time increases the seizure induction threshold.

Risk factors associated with lipomyelomeningocele: a case-control study.

BACKGROUND: In general, it seems that both genetic and environmental factors play important roles in the induction of neural tube defects. Lipomyelomeningocele (LipoMMC) is a rather common type of closed neural tube defect, but only limited studies have investigated the potential risk factors of this anomaly. Therefore, the purpose of this case-control study was to investigate the risk factors involved in LipoMMC formation. MATERIAL AND METHOD: Various risk factors were evaluated in 35 children between 1 month and 10 years of age with LipoMMC in a hospital-based case-control study. The 2 control arms consisted of 35 children with myelomeningocele (MMC group) and 35 children with congenital anomalies other than central nervous system problems (control group). All groups were matched for age and visited the same hospital. A structured questionnaire was used for the collection of all data, including the mothers' weight and height during pregnancy, education, reproductive history, previous abortions, and socioeconomic status, as well as the parents' consanguinity and family history of the same anomalies. RESULTS: Univariate analysis of the children with LipoMMC compared to the control group showed that the use of periconceptional folic acid supplementation was significantly lower in the MMC and LipoMMC groups compared to the control group. In addition, comparison of the MMC and control groups revealed statistically significant differences regarding the use of folic acid and maternal obesity. In multivariate analysis, use of folic acid in the periconceptional period and during the first trimester was an independent risk factor for LipoMMC and MMC. Furthermore, maternal obesity was a significantly positive risk factor for MMC. CONCLUSION: The probable risk factors for LipoMMC were investigated in this case-control study. Consumption of folic acid in the periconceptional period and during the first trimester is an independent protective factor against LipoMMC. It seems that larger studies are needed to examine other possible risk factors.