Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Neurological disorders and violence: a systematic review and meta-analysis with a focus on epilepsy and traumatic brain injury

The objectives of this study were to systematically review and meta-analyze the research literature on the association of common neurological disorders and violence. Keywords relating to neurological disorders and violence were searched between 1966 and August 2008. Case–control and cohort studies were selected. Odds ratios of violence risk in particular disorders compared with controls were combined using fixed-effects meta-analysis with the data presented in forest plots. Sensitivity analyses were conducted to identify possible differences in risk estimates across surveys. Information on risk factors for violence was extracted if replicated in more than one study. Nine studies were identified that compared the risk of violence in epilepsy or traumatic brain injury compared with unaffected controls. For the epilepsy studies, the overall pooled odds ratio for violent outcomes was 0.67 [95% confidence interval (CI) 0.46–0.96]. For traumatic brain injury, the odds ratio was 1.66 (95% CI 1.12–2.31). An additional 11 case–control studies investigated factors associated with violence in epilepsy and traumatic brain injury. It was not possible to meta-analyze these data. Comorbid psychopathology was associated with violence. Data on other neurological conditions was limited and unreplicated. In conclusion, although the evidence was limited and methodological quality varied, epilepsy and traumatic brain injury appeared to differ in their risk of violence compared with control populations. Longitudinal studies are required to replicate this review’s provisional findings that epilepsy is inversely associated with violence and that brain injury modestly increases the risk, and further research is needed to provide information on a broader range of risk factors.     

Successful treatment of superior vena cava syndrome with urokinase in an infant

An 11-month-old infant with a central venous catheter for total parenteral nutrition for short gut syndrome developed head and neck swelling. A thrombus at the catheter tip occluding the superior vena cava was demonstrated roentgenographically. A 48-hr infusion of urokinase (4400 units/kg/hr) was administered for thrombolysis. The thrombus cleared clinically and roentgenographically without adverse effects. There has been no recurrence of the superior vena cava syndrome. Urokinase infusion is an alternative to immediate catheter removal in selected patients.     

Modification of Blood Vessel Diameter Following Perivascular Application of Botulinum Toxin-A

The purpose of this study was to demonstrate that perivascularly applied botulinum toxin-A (BTX) increases the diameter of treated blood vessels in a rat femoral vessel exposure model. Six adult Sprague–Dawley rats were used and bilateral femoral artery and vein exposures were performed. Five units of BTX were applied to the experimental side and an equal volume of sterile saline was applied to the control side. Digital images of the vessels were obtained at the following time points: pretreatment, immediately posttreatment, and postoperative days (POD) 1, 14, and 28. Vessel diameters were equivalent at baseline and immediately following application of BTX and saline. The BTX artery was significantly larger than the control artery on POD 1 and 14. The BTX treated artery was significantly larger than all other vessels on POD 14 (p < 0.05) as well as all prior time points (p < 0.01). Direct perivascular application of BTX increases the diameter of rat femoral vessels as early as POD 1. The affect is most robust on POD 14 where the artery was significantly larger than all other vessels at all time points. It is likely that the increased diameter of blood vessels results in an increased blood flow across the area of dilation. Such an increase in flow may serve to improve end-organ perfusion in microvascular procedures.     

Hepatic UDP-glucose 13C isotopomers from [U-13C]glucose: a simple analysis by 13C NMR of urinary menthol glucuronide.

Menthol glucuronide was isolated from the urine of a healthy 70-kg female subject following ingestion of 400 mg of peppermint oil and 6 g of 99% [U-(13)C]glucose. Glucuronide (13)C-excess enrichment levels were 4-6% and thus provided high signal-to-noise ratios (SNRs) for confident assignment of (13)C-(13)C spin-coupled multiplet components within each (13)C resonance by (13)C NMR. The [U-(13)C]glucuronide isotopomer derived via direct pathway conversion of [U-(13)C]glucose to [U-(13)C]UDP-glucose was resolved from [1,2,3-(13)C(3)]- and [1,2-(13)C(2)]glucuronide isotopomers derived via Cori cycle or indirect pathway metabolism of [U-(13)C]glucose. In a second study, a group of four overnight-fasted patients (63 +/- 10 kg) with severe heart failure were given peppermint oil and infused with [U-(13)C]glucose for 4 hr (14 mg/kg prime, 0.12 mg/kg/min constant infusion) resulting in a steady-state plasma [U-(13)C]glucose enrichment of 4.6% +/- 0.6%. Menthol glucuronide was harvested and glucuronide (13)C-isotopomers were analyzed by (13)C NMR. [U-(13)C]glucuronide enrichment was 0.6% +/- 0.1%, and the sum of [1,2,3-(13)C(3)] and [1,2-(13)C(2)]glucuronide enrichments was 0.9% +/- 0.2%. From these data, flux of plasma glucose to hepatic UDPG was estimated to be 15% +/- 4% that of endogenous glucose production (EGP), and the Cori cycle accounted for at least 32% +/- 10% of GP.     

Comparison of novel computer detectors and human performance for spike detection in intracranial EEG.

OBJECTIVE: Interictal spikes in intracranial EEG (iEEG) may correlate with epileptogenic cortex, but review of interictal iEEG is labor intensive. Accurate automated spike detectors are necessary for understanding the role of spikes in epileptogenesis. METHODS: The sensitivity, accuracy and reproducibility of three automated iEEG spike detectors were compared against two human EEG readers using iEEG segments from eight patients. A consensus set of detections was generated for detector calibration. Spike verification was calculated after both human EEG readers independently reviewed all detections. RESULTS: Humans and two of the three automated detectors demonstrated comparable accuracy. In four patients, automated spike detection sensitivity was >70% and accuracy was >50%. In the remaining four patients, EEG background morphology resulted in poorer performance. Blinded human verification accuracy was 76.7+/-6.6% for computer-detected spikes, and 84.5+/-4.1% for human-detected spikes. CONCLUSIONS: Automated iEEG spike detectors perform comparably to humans, but sensitivity and accuracy are patient dependent. Humans verified the majority of computer-detected spikes. SIGNIFICANCE: In some patients automated detectors may be used for mapping spike occurrences in epileptic networks. This may reveal associations between spike distribution, seizure onset, and pathology.     

State smoking prevalence estimates: a comparison of the Behavioral Risk Factor Surveillance System and current population surveys.

OBJECTIVES: This study examined whether there are systematic differences between the Behavioral Risk Factor Surveillance System (BRFSS) and the Current Population Survey (CPS) for state cigarette smoking prevalence estimates. METHODS: BRFSS telephone survey estimates were compared with estimates from the US Census CPS tobacco-use supplements (the CPS sample frame includes persons in households without telephones). Weighted overall and sex- and race-specific BRFSS and CPS state estimates of adults smoking were analyzed for 1985, 1989, and 1992/1993. RESULTS: Overall estimates of smoking prevalence from the BRFSS were slightly lower than estimates from CPS (median difference: -2.0 percentage points in 1985, -0.7 in 1989, and -1.9 in 1992/1993; P < .05 for all comparisons), but there was variation among states. Differences between BRFSS and CPS estimates were larger among men than among women and larger among Blacks than among Hispanics or Whites; for most states, these differences were not significant. CONCLUSIONS: The BRFSS generally provides state estimates of smoking prevalence similar to those obtained from CPS, and these are appropriate for ongoing state surveillance of smoking prevalence.