Induction of diabetes in cynomolgus monkey with one shot of analytical grade streptozotocin

Backgrounds:Streptozotocin(STZ)-induced diabetic monkey is a wide used preclinical animal model for the investigation of diabetes such as islet transplantation and development of diabetic drugs.There are serious side effects of this method,including nausea,emesis,weight loss,liver damage,renal failure,and metabolic acidosis.In order to reduce the side effects,diabetic monkeys were induced using clinicalgrade STZ.However,clinical-grade STZ is not available in China.Here,we establised a method by using 100 mg/kg analytical-grade STZ to induce complete diabetes in cynomolgus monkey without generating adverse effects to liver and renal.Methods:Three cynomolgus monkeys were used in this study.100 mg/kg STZ dissolved in normal saline and infused through vein line in 5 minutes after indwelling catheter in the carotid artery and jugular vein.After the STZ administration,blood glucose levels were examined every 1 or 2 hours in the first 48 hours.Then,blood glucose levels were examined twice per day during the first week after the STZ injection.Insulin and C-peptide levels were measured by ELISA.Blood chemistry of hepatic and renal function tests were performed.Insulin and glucagon expression in the islet of diabetic monkey and normal monkey were examined by immunohistochemistry assays.Results:The stimulated C-peptide level(Intravenous glucose tolerance test)which is less than 0.5 ng/mL,the triphasic blood glucose response and the destroyed β cell suggested the complete induction of diabetes model.No apparent adverse effects were observed including no signs of vomiting and toxicity after STZ injection.Conclusion:In summary,we established a safe and reproducible STZ-induced diabetic cynomolgus monkey model for islet transplantation which will be used to develop novel approaches for the treatment of diabetes.

Identifying and localizing of seismogenic electromagnetic anomalies from data observed by permanent MT stations

In this research, an arbitrarily oriented electric dipole at subsurface is used to simulate Seismogenic Electromagnetic(SEM) radiation emanating from a seismic zone during its gestation phase. Analytical synthesis of responses at the Lijiang magnetotelluric(MT) station has revealed that SEM radiation could induce identifiable anomalies in the electromagnetic(EM)spectrum, apparent resistivity and phase within specific frequency bands. Background variations were extracted from long-term observation data of Dali and Lijiang MT stations, enabling the identification of SEM anomalies related to the Yunlong and Yangbi earthquakes. Multiple parameters of dipole sources at subsurface were obtained by applying the Differential Ant Colony Optimization(DACO) algorithm to anomalous data of two stations with multi-frequencies and various response functions. The spatial distribution of these predicted dipoles is predominantly clustered in or around the seismogenic area, with their azimuthal orientation aligning towards the seismogenic fault in general. This study has demonstrated the potential of using subsurface electric dipole simulations for SEM radiation analysis, offering a feasible approach for the prediction and understanding of seismogenic zones.