Comparison of artificial neural network and logistic regression models for prediction of mortality in head trauma based on initial clinical data

Background  

In recent years, outcome prediction models using artificial neural network and multivariable logistic regression analysis have been developed in many areas of health care research. Both these methods have advantages and disadvantages. In this study we have compared the performance of artificial neural network and multivariable logistic regression models, in prediction of outcomes in head trauma and studied the reproducibility of the findings.     

Prediction of maxillary third molar impaction in adolescent orthodontic patients

The purpose of this study was to identify risk factors for maxillary third molar impaction in adolescent orthodontic patients. Radiographs made before treatment (T1) and after treatment (T2) and at a minimum of 10 years postretention (T3) of 132 patients that allowed accurate diagnosis of impaction vs eruption of one or both maxillary third molars were evaluated. Although univariate logistic regression revealed that the decision to extract premolars reduced the risk of impaction by 76% (P < .01), this parameter was not included in the final prediction model at T1. Multiple logistic regression analyses revealed that third molar impaction could be predicted at T1 according to the size of the retromolar space and the amount of mesial molar movement that will occur during active appliance therapy, reducing the risk of impaction by 22% and 34% for every millimeter increase in distance, respectively (P < .01). At T2, multiple logistic regression revealed that the odds of impaction were more than 60 times higher (P < .01) if the third molar was angulated mesially as compared with less than 30 degrees distally relative to the occlusal plane and almost five times (P < .05) higher if the third molar was angulated more than 30 degrees distally as compared with less than 30 degrees distally. Similar analyses at T2 showed 29% reduced risk of impaction for every millimeter increase in retromolar space and 18% reduced risk for every degree increase in angle MP/SN (P < .01).     

Isolated optic nerve lymphoma diagnosed by optic nerve biopsy

PURPOSE: To report a case of isolated optic nerve lymphoma diagnosed by optic nerve biopsy. DESIGN: Case report. METHODS: A 66-year-old woman was referred to the Neuro-Ophthalmology Service because of a decrease in visual acuity and right optic disk edema. RESULTS: A magnetic resonance image of the brain showed only enhancement of the optic nerve. An examination that included ANA, c-ANCA, p-ANCA, Lyme titers, FTA-ABS, ACE level, chest x-ray, and lumbar puncture was negative. Because of rapid progression on clinical examination and serial imaging, an optic nerve biopsy was performed, which showed B-cell lymphoma. CONCLUSION: Optic nerve lymphoma can be confused with a variety of inflammatory and neoplastic infiltrations of the optic nerve on clinical and radiographic examinations. Optic nerve biopsy can be valuable in diagnosing isolated optic nerve lymphoma if other diagnostic tests are unrevealing, but the procedure carries considerable risk of loss of visual acuity and should be recommended judiciously.     

Multifocal ERG in ethambutol associated visual loss

AIM: To determine the anatomical site and extent of electrophysiological dysfunction in patients with ethambutol associated visual loss. METHODS: A comparative case series. Four patients with ethambutol associated visual loss underwent multifocal electroretinography (mERG). Two patients had advanced visual loss while two had early signs of toxicity. The N1-P1, N1, P1 amplitudes, N1, and P1 latencies were compared to 10 age and sex matched controls. RESULTS: mERG abnormalities were detected in the ethambutol treated patients. The N1 amplitude was significantly lower in the ethambutol treated patients than in the control group. CONCLUSION: Ethambutol is possibly toxic to the retina, and not only the optic nerve. The multifocal ERG may be of value to diagnose and monitor patients taking ethambutol.     

Fractionated stereotactic radiotherapy for parasellar meningiomas: a preliminary report of visual outcomes

BACKGROUND/AIM: Fractionated stereotactic radiotherapy (FSRT) is a new treatment for brain tumours that are close to critical structures, such as the visual apparatus. This study aims to assess the visual outcomes for patients with parasellar meningioma following FSRT. METHODS: A retrospective, non-comparative case series of 13 patients with parasellar meningiomas who were treated in one institution with FSRT between January 1995 and January 2001. RESULTS: 13 patients (26 eyes) were followed for a mean of 2 years. Visual acuity improved in four eyes (12.5%), remained stable in 18 eyes (75%), and worsened in three eyes (12.5%). Visual field improved in 15 eyes (57%), remained stable in six eyes (23%), and worsened in four eyes (15%). No adverse visual outcome occurred as a result of radiation. CONCLUSION: These preliminary findings suggest that FSRT is a safe and effective treatment for parasellar meningiomas.     

Seventy-kilodalton protein density in Porites spp.: possible useful proxy for cold stress in coral reefs

During the last two decades, significant deterioration of tropical coral reef communities has been observed, and based on current theories, environmental stressors are among the main causes of this. The density of 70-kDa heat shock proteins (Hsps) may present as a potential tool for the determination of cold stress on Porites spp. Therefore, density of Hsp70 proteins, concentration of total protein and seawater temperature was measured on a seasonal basis. Sampling was conducted, from the dominant genus of Porites spp. at four separate time points over 1?year (2003–2004) and at a depth of 3?m. Our results showed no significant correlations between total protein and seawater temperature. Our results also indicated that Porites spp. from the Persian Gulf is sensitive to low range of temperature (15–27°C). Maximum Hsp70 density and minimum average number of colonies in Porites spp. were obtained in winter. Also, a significant negative correlation was observed between Hsp70 density and water temperatures (p?>?0.05). Therefore, density of Hsp70 may be used as indicator of cold stress in Porites spp.     

Simultaneous determination of epinephrine and uric acid at a gold electrode modified by a 2-(2,3-dihydroxy phenyl)-1, 3-dithiane self-assembled monolayer

In the present paper, the use of a gold electrode modified by 2-(2,3-dihydroxy phenyl)-1,3-dithiane self-assembled monolayer (DPDSAM) for the determination of epinephrine (EP) and uric acid (UA) was described. Initially, cyclic voltammetry was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge transfer rate constant, k_s, and transfer coefficient, α, were calculated. Next, the mediated oxidation of EP at the modified electrode was described. At the optimum pH of 8.0, the oxidation of EP occurs at a potential about 155 mV less positive than that of an unmodified gold electrode. The values of electron transfer coefficients (α = 0.356), catalytic rate constant (k = 1.624 × 10⁴ M⁻¹ s⁻¹) and diffusion coefficient (D = 1.04 × 10⁻⁶ cm² s⁻¹) were calculated for EP, using electrochemical approaches. Based on differential pulse voltammetry, the oxidation of EP exhibited a dynamic range between 0.7 and 500.0 μM and a detection limit (3σ) of 0.51 μM. Furthermore, simultaneous determination of EP and UA at the modified electrode was described. Finally, this method was used for the determination of EP in EP ampoule.