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The effects of apamin and crotamine on the EEG of rats: a computer-assisted study
First Asia-Pacific Congress
39
A LAROE number of enterotoxins produced by different diarrhoeagenic bacteria have been described. It is essential to know if there exists any interrelationship amongst these toxins. Similarities relating to antigenic structure, receptor site, mode of action and gene composition have been well established in the case of heat-labile toxins of V. cholerae 01 and E. coll. Enterotoxins produced by V. cholerae non 01 and V. mimicus have been found to be similar in subunit structure and immunobiological properties with favourable indications of at least partial genetic homology. V. fluvialis, Aeromonas and Piesiomonas enterotoxins were found to activate cAMP. A new enterotoxin produced by V. cholerae 01 strains with or without the CT gene has been found to be antigenically similar to that of the V. fluvialis toxin. Campylobacter isolates from man and the environment have been shown to elaborate a diarrhoeagenic toxin that is immunobiologically similar to CT. Salmonella strains also have been found to produce a heat-labile toxin that is similar in certain properties to that of V. cholerae 01. Some strains of E.coli produce a Shiga-like toxin. All these observations indicate the existence of similarities in either one or more character(s) amongst the different enterotoxins or various diarrhoeagenic bacteria.
The effects o f apamin and crotamine on the EEG o f rats: a computer-assisted study. M. K. SIM, l C. K. TAN2and P. Gopalakrishnakone2 (~Department of Pharmacology and 2Department of Anatomy, Faculty of Medicine, National University of Singapore, Singapore 0511). ONE WAYof examining the effects of a toxin on the central nervous system is to study the electroencephalogram (EEG) before and immediately after intracerebroventricular administration of the toxin. In the past such studies were handicapped by the laborious task of analysing the EEG pattern manually. The employment of a computer to analyse the EEG data has made EEG studies more precise, reliable and attractive. In this poster presentation we display the computer-assisted analysed data of the effects of apamin, a bee toxin, on the EEG of rats. The analysed EEG data are presented in various forms of periodogram, power spectrum and per cent time occupied by certain frequency ranges. Statistical analysis of the data is also incorporated. Our data confirmed the general findings of JANICKIet al. (1985) in that the toxin caused an immediate drop in the amplitude and a shift of the mean frequency of the EEG. However, unlike Janicki and co-workers who employed the manual method of EEG analysis, we were able to decipher the actual frequency bands that were affected by the toxin and calculate the statistical significance of the changes observed. Preliminary data obtained with another toxin, crotamine (from the South American rattlesnake) showed that the snake toxin at higher dose (200 gg) produced effects opposite to those induced by apamin. JANICKI, P. et al. (1985) The effects of apamin in rats with trigeminal or high spinal transsection of the central nervous system. Toxicon 23, 9 9 3 - 996.
Renal pathogenesis o f snake bite: a review. V. SITPRIJA (Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand). THE SPECTRUMof renal changes in snake bite includes glomerulonephritis, vasculitis, tubular necrosis, interstitial nephritis, infarct and cortical necrosis. Through clinical and experimental studies by various investigators 3 mechanisms are believed to be involved in the pathogenesis of these renal lesions. (1) Non-specific effects of venoms. Chemical mediators released during envenomation can lead to hypotension, hemorrhage, hypovolemia, intravascular coagulation, intravascular hemolysis and myoglobinuria, leading to renal ischemia and tubular necrosis. Tubulo-interstitial lesions, infarct and cortical necrosis are usually caused by these non-specific effects. (2) Immunologic reactions. Immune complex glomerulonephritis may occur in snake bite, irrespective of antivenin therapy. This has been shown in renal biopsy studies when performed later in the course of the disease. (3) Direct nephrotoxicity. Vasculitis and various forms of glomerular changes can be seen in some viper bites. The direct role of the venom on tubular changes is less clear. However, in animal experiments depolarization of proximal tubules has been shown following Russell's viper envenomation and the effect was concentration dependent.
Suspected cyclopiazonic acid mycotoxicosis o f quail in Indonesia. D. R. STOLTZ, R. WIDIASTUTI, R. MARYAM, B. TRI AKOSO, AMANG and D. UNRUH (Balai Penelitian Veteriner, Bogor, and Balai Penyidikan Penyakit Hewan, Yogyakarta, Indonesia). LIVESTOCK feeds in Indonesia, especially those containing corn, are commonly contaminated with afiatoxins. Since cyclopiazonic acid (CPA) may be produced by aflatoxigenic Aspergillus flavus, and by other fungal species, the presence of CPA in local feeds was anticipated. Twenty-six batches of corn from a Bogor poultry feedmill were analyzed for aflatoxins, CPA, ochratoxin A and zearalenone by TLC. CPA was detected in 21 of the 26 corn samples at concentrations as high as 9 ppm. CPA was always accompanied by other mycotoxins, especially aflatoxins. Although this corn was not associated with any disease in poultry, we had the opportunity
39
A LAROE number of enterotoxins produced by different diarrhoeagenic bacteria have been described. It is essential to know if there exists any interrelationship amongst these toxins. Similarities relating to antigenic structure, receptor site, mode of action and gene composition have been well established in the case of heat-labile toxins of V. cholerae 01 and E. coll. Enterotoxins produced by V. cholerae non 01 and V. mimicus have been found to be similar in subunit structure and immunobiological properties with favourable indications of at least partial genetic homology. V. fluvialis, Aeromonas and Piesiomonas enterotoxins were found to activate cAMP. A new enterotoxin produced by V. cholerae 01 strains with or without the CT gene has been found to be antigenically similar to that of the V. fluvialis toxin. Campylobacter isolates from man and the environment have been shown to elaborate a diarrhoeagenic toxin that is immunobiologically similar to CT. Salmonella strains also have been found to produce a heat-labile toxin that is similar in certain properties to that of V. cholerae 01. Some strains of E.coli produce a Shiga-like toxin. All these observations indicate the existence of similarities in either one or more character(s) amongst the different enterotoxins or various diarrhoeagenic bacteria.
The effects o f apamin and crotamine on the EEG o f rats: a computer-assisted study. M. K. SIM, l C. K. TAN2and P. Gopalakrishnakone2 (~Department of Pharmacology and 2Department of Anatomy, Faculty of Medicine, National University of Singapore, Singapore 0511). ONE WAYof examining the effects of a toxin on the central nervous system is to study the electroencephalogram (EEG) before and immediately after intracerebroventricular administration of the toxin. In the past such studies were handicapped by the laborious task of analysing the EEG pattern manually. The employment of a computer to analyse the EEG data has made EEG studies more precise, reliable and attractive. In this poster presentation we display the computer-assisted analysed data of the effects of apamin, a bee toxin, on the EEG of rats. The analysed EEG data are presented in various forms of periodogram, power spectrum and per cent time occupied by certain frequency ranges. Statistical analysis of the data is also incorporated. Our data confirmed the general findings of JANICKIet al. (1985) in that the toxin caused an immediate drop in the amplitude and a shift of the mean frequency of the EEG. However, unlike Janicki and co-workers who employed the manual method of EEG analysis, we were able to decipher the actual frequency bands that were affected by the toxin and calculate the statistical significance of the changes observed. Preliminary data obtained with another toxin, crotamine (from the South American rattlesnake) showed that the snake toxin at higher dose (200 gg) produced effects opposite to those induced by apamin. JANICKI, P. et al. (1985) The effects of apamin in rats with trigeminal or high spinal transsection of the central nervous system. Toxicon 23, 9 9 3 - 996.
Renal pathogenesis o f snake bite: a review. V. SITPRIJA (Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok, Thailand). THE SPECTRUMof renal changes in snake bite includes glomerulonephritis, vasculitis, tubular necrosis, interstitial nephritis, infarct and cortical necrosis. Through clinical and experimental studies by various investigators 3 mechanisms are believed to be involved in the pathogenesis of these renal lesions. (1) Non-specific effects of venoms. Chemical mediators released during envenomation can lead to hypotension, hemorrhage, hypovolemia, intravascular coagulation, intravascular hemolysis and myoglobinuria, leading to renal ischemia and tubular necrosis. Tubulo-interstitial lesions, infarct and cortical necrosis are usually caused by these non-specific effects. (2) Immunologic reactions. Immune complex glomerulonephritis may occur in snake bite, irrespective of antivenin therapy. This has been shown in renal biopsy studies when performed later in the course of the disease. (3) Direct nephrotoxicity. Vasculitis and various forms of glomerular changes can be seen in some viper bites. The direct role of the venom on tubular changes is less clear. However, in animal experiments depolarization of proximal tubules has been shown following Russell's viper envenomation and the effect was concentration dependent.
Suspected cyclopiazonic acid mycotoxicosis o f quail in Indonesia. D. R. STOLTZ, R. WIDIASTUTI, R. MARYAM, B. TRI AKOSO, AMANG and D. UNRUH (Balai Penelitian Veteriner, Bogor, and Balai Penyidikan Penyakit Hewan, Yogyakarta, Indonesia). LIVESTOCK feeds in Indonesia, especially those containing corn, are commonly contaminated with afiatoxins. Since cyclopiazonic acid (CPA) may be produced by aflatoxigenic Aspergillus flavus, and by other fungal species, the presence of CPA in local feeds was anticipated. Twenty-six batches of corn from a Bogor poultry feedmill were analyzed for aflatoxins, CPA, ochratoxin A and zearalenone by TLC. CPA was detected in 21 of the 26 corn samples at concentrations as high as 9 ppm. CPA was always accompanied by other mycotoxins, especially aflatoxins. Although this corn was not associated with any disease in poultry, we had the opportunity