Ferumoxytol-enhanced MR imaging for differentiating intrapancreatic splenules from other tumors

Objectives Ferumoxytol is an ultra-small superparamagnetic iron oxide (USPIO) agent that is taken up by splenic tissue. This study describes our initial institutional experience of ferumoxytol-enhanced MRI (feMRI) for differentiating intrapancreatic splenules (IPS) from other pancreatic lesions. Methods In this retrospective study, patients with computed tomographic imaging that identified small enhancing lesions in the tail of the pancreas subsequently underwent feMRI for further characterization. The feMRI protocol included T2-weighted (T2w) imaging with and without fat suppression (FS), R2* mapping, diffusion-weighted imaging (DWI), and T1-weighted (T1w) imaging with FS, prior to contrast injection. Immediately after slow intravenous infusion with 3 mg/kg body weight ferumoxytol, T1w was repeated. Delayed imaging with all sequences were obtained 24–72 h after ferumoxytol administration. Results Seven patients underwent feMRI. In two patients, the pancreatic lesions were presumed as pancreatic neuroendocrine tumor (PNET) from feMRI and in the remaining 5 IPS. One of the two patients with PNET was symptomatic for NET. In another symptomatic patient with pathologically proven duodenal NET and suspected PNET, the pancreatic lesion was proven to be an IPS on feMRI. IPS demonstrated strong negative enhancement in feMRI on T2w and increased R2* values consistent with splenic tissue, while the presumed PNETs did not enhance. T2w FS was helpful on the pre-contrast images to identify IPS, while R2* did on post-contrast images. Neither DWI nor T1w contributed to differentiating PNETs from IPS. Conclusions This study demonstrates the potential utility of feMRI as a helpful adjunct diagnostic tool for differentiating IPS from other pancreatic lesions. Further studies in larger patient cohorts are needed.

Comparative Toxicological Studies between Amikacin and Tobramycin Given Alone or with Calcium Gluconate in Rabbits

This study consists of two experiments conducted to explore a toxicological comparison between tobramycin sulphate and amikacin sulphate, and to explore the role of calcium gluconate in antagonizing or reducing the main toxic side effects of tobramycin and amikacin like nephrotoxicity, ototoxicity and neuromuscular blockade.The first experiment was designed to study and measure the acute toxicity of these drugs by using the Up and Down method, which showed that the value of intravenous LD50 of both drugs increased almost twice as much from 154.8 to 294.8 mg/kg for tobramycin and from 437.1 to 737.1 mg/kg for amikacin after the pretreatment with calcium gluconate.The second experiment was performed on rabbits injected with selected toxic dose considered as LD50 of tobramycin and amikacin given by intravenous IV route for the observation of the neurotoxicity signs and recording their appearance time, until the observation of certain definite neurotoxic signs such as loss of righting reflex. At that time, calcium gluconate was given by slow intravenous infusion (over 5-10 minutes) at a high range of therapeutic dose 45mg/kg and the time of disappearance of neuromuscular blockade signs with the number of life and dead animal were recorded for each treatment.The results of this experiment showed that although tobramycin was more potent in inducing neurotoxic effects according to the dose used but amikacin is seems to be more efficacious in developing neurotoxic signs response according to it is short appearance and disappearance time of toxic signs after amikacin and calcium treatment, in comparison with that of tobramycin and calcium treatment.

High-resolution electrocardiography in dogs under doxorubicin-induced cardiomyopathy

The occurrence of late potentials in dogs under doxorubicin-induced cardiomyopathy and their relationship with the development of ventricular arrhythmias or sudden death were studied. Seven adult mongrel dogs of both sexes were used. Cardiomyopathy was induced by slow intravenous infusion of doxorubicin (30mg/m²) at 21-day intervals, until a total cumulative dose of 240mg/m² was reached. Animals were monitored by echocardiography. After the induction of cardiomyopathy, high-resolution electrocardiography was recorded. Late potentials were observed in two animals that suddenly died a few days later.

Glucose administration before exercise modulates catecholaminergic responses in glycogen-depleted subjects

Gozal, David, Patrice Thiriet, Jean Marie Cottet-Emard, Dieudonné Wouassi, Emmanuel Bitanga, André Geyssant, Jean Marc Pequignot, and Marcel Sagnol. Glucose administration before exercise modulates catecholaminergic responses in glycogen-depleted subjects. J. Appl. Physiol. 82(1): 248–256, 1997.—In glycogen-depleted subjects (GD) a nonlinear increase in epinephrine (Epi) and norepinephrine (NE) parallels blood lactate (La) during graded exercise. The effect of glucose (Glc) supplementation and route of administration on these relationships was studied in 26 GD athletes who were randomly assigned to receive 1.3 g/kg Glc by slow intravenous infusion (IV; n = 9), oral administration (PO; n = 9), or artificially sweetened placebo in 1 liter of water (Asp; n = 8) in the 2 h preceding a graded maximal exercise. Performance and La were similar among the three groups in normal glycogen (NG) or GD conditions. However, slightly improved performances were observed in GD compared with NG and were associated with a shift to the right in La curves. Blood Glc concentrations were higher in IV and PO before exercise, but they rapidly decreased to lowest levels in IV, gradually decreased over time in PO, and remained stable in Asp or NG. Insulin concentrations were highest in IV and lowest in Asp and NG at onset of exercise, rapidly decreasing in IV and PO although remaining at higher levels than in Asp or NG. In contrast, higher serum levels of free fatty acids were measured during exercise in Asp with no significant differences in glucagon or glycerol among the three groups. Free and sulfated NE increases were smaller in IV than in PO and Asp on exhaustion. In contrast, free and conjugated Epi were most increased in IV, with smallest increases in Asp. Dopamine levels were most increased in IV at exhaustion. We conclude that the changes of Epi and NE concentrations, associated with the activation of glucoregulatory mechanisms, including hyperinsulinemia, display different magnitude and time courses during exercise in GD subjects who receive oral vs. intravenous load of Glc before exercise. We speculate that the magnitude of insulin surge after acutely increased Glc before exercise in GD subjects may exert dissociative effects on adrenal-dependent glycogenolysis and on sympathetic responses.