Epileptic seizure anticipation and localisation of epileptogenic region using EEG signals.

Electric activity of brain gets disturbed prior to epileptic seizure onset. Early prediction of an upcoming seizure can help to increase effectiveness of antiepileptic drugs. The scalp electroencephalogram signals contain information about the dynamics of brain and have been used to predict an upcoming seizure and localise its zone. The objective of this paper is to localise the epileptogenic region and predict an upcoming seizure at the earliest. To localise epileptogenic region, Electroencephalogram signals are categorised into four regions of brain (Frontal, Temporal, Parietal and Central). For each signal seventy-two (72) parameters in frequency domain have been extracted by using ten minute non overlapping window. Four prominent ratio parameters, γ1/γ5, γ3/γ1, θ/γ2 and γ4/θ have been identified as best parameters based on relative fisher score. Zone 2 shows the highest change in all the parameters as compared to the other zones. So, temporal region is identified as the epileptogenic region in this work. For prediction of the epileptic seizure machine learning algorithm artificial neural network (ANN) is proposed. The proposed machine learning algorithm has an accuracy of 92.3%, sensitivity of 100% and specificity of 83.3%.

Post-transplant lymphoproliferative disease in liver transplantation.

Post-transplant lymphoproliferative disease (PTLD) is a well recognized complication of solid organ transplantation and therapeutic immunosuppression, first reported in 1968. PTLD incorporates a spectrum of abnormalities ranging from a benign infectious mononucleosis-like illness to non-Hodgkin's lymphoma with nodal and extranodal site involvement. The first liver transplant was performed at our institution in January 1982. This retrospective study examined the incidence of PTLD, reason for the original transplants, presenting symptoms, radiological findings, immunosuppression regimens and outcomes of these patients. From a total of 2005 adult liver transplants, 23 patients (1.1%) were identified with PTLD. The average age of these patients at the time of transplant was 46.5 years, with a ratio of female-to-male of 14:9. Indication for transplant ranged from primary biliary cirrhosis (eight patients) to epitheloid haemangioendothelioma (one patient). The average time interval between transplant and diagnosis of PTLD was 50 months. Imaging abnormalities identified included generalized lymphadenopathy, liver and portal masses, splenic enlargement, bowel, eye, cerebral and neck involvement; and in two patients, no radiological abnormality. The most common histological findings ranged from B-cell non-Hodgkin's lymphoma (five patients) to early PTLD in one patient. Our rate of PTLD is lower compared with published literature and demonstrates a much longer time interval from transplant to occurrence of PTLD than previously appreciated. This could be secondary to a low immunosuppression therapy followed at our institution. From a few months to several years after liver transplantation, the radiologist needs to be alert to the possibility of PTLD and thorough imaging is required to detect the wide variety of potential presentations.

Micro determination of ascorbic acid using methyl viologen.

A new simple and sensitive analytical spectrophotometric method is developed for the determination of ascorbic acid reduces methyl viologen to form a stable blue coloured free radical ion. This method has a sensitivity and lower limit detection of 0.1mugml(-1) of ascorbic acid (0.1ppm) which is comparable to the flow injection analysis reported earlier. Beer's law is obeyed over the concentration range of 1.0-10mugml(-1) of ascorbic acid per 10ml of the final solution (0.1-1.0mugml(-1)) at 600nm. The molar absorptivity and Sandell's sensitivity were found to be 1.5x10(5)+/-100lmol(-1)cm(-1) and 0.001mugcm(-2), respectively. The method has been applied to the determination of ascorbic acid in food, pharmaceuticals and biological samples.

TLC-spectrophometric separation and trace determination of monocrotophos and dichlorvos in enviromental and biological samples.

Organophosphorus insecticides, monocrotophos and dichlrovos are increasingly being used in agriculture to control insects on a wide range of crops. Their ready access has resulted in misuse in many instances of homicidal and suicidal poisoning cases. This paper describes about a chromogenic spray reagent for the detection/determination of monocrophos and dichlrovos in environmental and biological samples by TLC and spectrophotometric method. Monocrotophos and dichlorvos on alkaline hydrolysis yield N-methyl acetoacetamide and dichlroacetaldehyde respectively, which in turn react with diazotized p-amino acetophenone to give red-violet and red coloured compounds. Other organophosphorus insecticides do not give this reaction. Moreover, organochlorine and synthetic pyrethroid insecticides and constituents of viscera (amino acids, peptides, proteins etc), which are generally coextracted with the insecticides, do not interfere. However, phenolic compounds and hydrolysed product of carbamate insecticides may interfere and differentiate from monocrotophos and dichlrovos by Rf values. The lower limit of detection is 0.2 mg for monocrotophos and 0.1 mg for dichlorovos. The absorption maxima of the reddish-violet and red colour formed by monocrotophos and dichlrovos, are measured at 560 nm and 540 nm respectively. Beer's Law is obeyed over the concentration range of 1.2 to 6.8 mg and 6.2 to 35 mg in the final solution volume of 25 mL. The molar absorptivity and Sandell's sensitivity of monocrotophos and dichlrovos were found to be 7.1 x 10(5) (+100) 1 mole(-1) cm(-1) and 0.008 mg cm(-2), 1.2 x 10(5) 1 mole(-1) cm(-1) and 0.003 mg cm(-2) respectively. The standard deviation and relative standard deviation were found be +/- 0.005 and 2.05% +/- 0.007 and 2.02% respectively. The developed method has been successfully applied to the detection and determination of monocrotophos and dichlrovos in environmental and biological samples.