Longitudinal magnetic resonance imaging reveals striatal hypertrophy in a rat model of long-term stimulant treatment.

Stimulant treatment is highly effective in mitigating symptoms associated with attention-deficit/hyperactivity disorder (ADHD), though the neurobiological underpinnings of this effect have not been established. Studies using anatomical magnetic resonance imaging (MRI) in children with ADHD have suggested that long-term stimulant treatment may improve symptoms of ADHD in part by stimulating striatal hypertrophy. This conclusion is limited, however, as these studies have either used cross-sectional sampling or did not assess the impact of treatment length on their dependent measures. We therefore used longitudinal anatomical MRI in a vehicle-controlled study design to confirm causality regarding stimulant effects on striatal morphology in a rodent model of clinically relevant long-term stimulant treatment. Sprague Dawley rats were orally administered either lisdexamfetamine (LDX, 'Vyvanse') or vehicle (N=12 per group) from postnatal day 25 (PD25, young juvenile) until PD95 (young adult), and imaged one day before and one day after the 70-day course of treatment. Our LDX dosing regimen yielded blood levels of dextroamphetamine comparable to those documented in patients. Longitudinal analysis of striatal volume revealed significant hypertrophy in LDX-treated animals when compared to vehicle-treated controls, with a significant treatment by time point interaction. These findings confirm a causal link between long-term stimulant treatment and striatal hypertrophy, and support utility of longitudinal MRI in rodents as a translational approach for bridging preclinical and clinical research. Having demonstrated comparable morphological effects in both humans and rodents using the same imaging technology, future studies may now use this rodent model to identify the underlying cellular mechanisms and behavioral consequences of stimulant-induced striatal hypertrophy.

[Challenges and opportunities for endoscopic ultrasound in the preoperative diagnosis of topical insulin the pancreas].

Insulinoma in most cases is monohormonal orthoendocrine tumor. This fact limits its searching area by a pancreas. However the insulinoma's clinical picture can be caused by other pathology. Therefore the main task of visual the tumor but also to use all the possibilities of each method for defining type of surgery and avoiding such errors and complications, as pancreatorrhage, damage of bile or pancreatic duct, necrosis of duodenal wall, etc. On the basis of our own experience of endoscopic ultrasound for 61 patients with 66 insulinomas, we have allocated the basic variants of insulinoma ultrasound pictures: hypoechoic, heteroechoic, isoechoic tumor, and also foci without a trustworthy contour. On the basis of the analysis of our own errors we have essentially added the technique, having used multiplane pancreas scanning and biplane tumor scanning. Important points in EUS algorithm are also the following items: detecting tumor relationship to pancreatic surface, distance from the tumor to the ducts, gastrointestinal wall and vessels--for definition of possibility of the tumor enucleation; careful scanning of pancreas even after detecting one tumor--for an exception of multiple tumors, especially at MEN-I; careful scanning of a contour of the gland for an exception of parapancreatic insulinomas; estimation of vascularization not only of the detected tumor and suspicious foci, but also of all the gland--for detection of hypervascularized isoechoic tumors; revealing and the description of focal changes, especially more homoechogeneous in comparison with surrounding parenchyma-- for selection patients for examination by other methods; scanning of zones of possible metastasis. Examination of patients with organic hyperinsulinism demands combined application of two or more techniques. Use of all modern possibilities of endosonography can put this technique on one of the first places in the diagnosis of insulinomas.

[Malignant insulinoma].

According to official statistics, malignant insulinomas account for a small fraction of gastroenteropathic endocrine neoplasms, the majority of insulinomas being essentially benign tumours. This paper reports a clinical case of malignant insulin-producing neuroendocrine tumour of the pancreas tail in a 28 year-old woman. She had multiple liver metastases and organic hyperinsulinism. Results of comprehensive examination of the patient at the Endocrinological Research Centre including laboratory diagnostic data and their evaluation are presented. Her surgical treatment was accomplished in N.N. Burdenko Facultative Surgery Clinic, I.M. Sechenov Moscow Medical Academy. Treatment strategy in the post-operative period and follow-up observations are described.