Application of high-performance liquid chromatography–UV detection to quantification of clenbuterol in bovine liver samples

A method for the determination of clenbuterol (CLB) concentration in bovine liver by reversed-phase high-performance liquid chromatography (HPLC) with UV detection was developed. The sample was extracted with acetonitrile and isopropanol, followed by HPLC analysis. A reverse-phase column C18 was used, with a UV detector at 214 nm and 0.05 M NaH₂PO₄ (pH 3.0)/acetonitrile (85:15, v/v) as the mobile phase. The accuracy of the analytical method was estimated by spiking bovine liver samples with three different concentrations of CLB (5.24 ng/g, 20.98 ng/g, and 41.96 ng/g) and recovery of 111.7%, 82.0%, and 84.8%, respectively, was obtained. The precision of the method was estimated by the relative standard deviation, which was < 4.74%. The limit of detection and quantification of CLB were 0.20 ng/g and 0.42 ng/g of liver sample, respectively, and the retention time was 24.82 minutes. The recent discovery of CLB contamination in Mexican food led to the specific inspection of a distribution center for this β-agonist, involving the analysis of a total of 78 bovine liver samples. Of all samples screened, 62% of them had concentrations above the maximum residue limit of 0.6 ng/g set by the United Nations Food and Agricultural Organization for CLB. The analytical method was found to be rapid, sensitive, accurate, repeatable, and reproducible, and could be applied to the measurement of CLB concentration in bovine liver.     

Neurotransmitter segregation: functional and plastic implications

Synaptic cotransmission is the ability of neurons to use more than one transmitter to convey synaptic signals. Cotransmission was originally described as the presence of a classic transmitter, which conveys main signal, along one or more cotransmitters that modulate transmission, later on, it was found cotransmission of classic transmitters. It has been generally accepted that neurons store and release the same set of transmitters in all their synaptic processes. However, some findings that show axon endings of individual neurons storing and releasing different sets of transmitters, are not in accordance with this assumption, and give support to the hypothesis that neurons can segregate transmitters to different synapses. Here, we review the studies showing segregation of transmitters in invertebrate and mammalian central nervous system neurons, and correlate them with our results obtained in sympathetic neurons. Our data show that these neurons segregate even classic transmitters to separated axons. Based on our data we suggest that segregation is a plastic phenomenon and responds to functional synaptic requirements, and to 'environmental' cues such as neurotrophins. We propose that neurons have the machinery to guide the different molecules required in synaptic transmission through axons and sort them to different axon endings. We believe that transmitter segregation improves neuron interactions during cotransmission and gives them selective and better control of synaptic plasticity.     

Dihydro-ergotamine and gas encephalography

Summary The favorable effect of Dihydro-Ergotamine in the course of gas encephalography was studied in sixty patients. The results obtained lead us to think that it is best to give an intramuscular injection of the drug a quarter of an hour before the examination. The examination is thereby facilitated and complications avoided. Pain, nausea and vomiting are suppressed, and headaches are lessened considerably. The action of Dihydro Ergotamine lasts about 12 h. The reappearance of the symptoms may make it necessary to give a second injection on the evening following the examination.

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Dihydro-ergotamin bei der Luftencephalographie

Zusammenfassung In 60 Patienten wurde der günstige Einfluß von Dihydro-Ergotamin während der Luftencephalographie untersucht. Die erzielten Ergebnisse ließen erkennen, daß es das Beste ist, dieses Mittel 1/4 Std. vor der Untersuchung intramuskulär zu injizieren. Die Untersuchung wird erleichtert und Komplikationen werden vermieden. Schmerzen, Übelkeit und Erbrechen werden unterdrückt und Kopfschmerzen wesentlich vermindert. Die Wirksamkeit von Dihydro-Ergotamin hält etwa 12 Std. an. Wenn die Symptome zurückkehren, kann eine zweite Injektion am Abend nach der Untersuchung erfolgen.

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Dihydro-ergotamine et encéphalographie gazeuse

Résumé L'auteur étudie l'effect favorable de la dihydroergotamine sur les suites d'une encéphalographie gazeuse dans 60 cas. L'injection intramusculaire est pratiquée un quart d'heure avant l'examen. L'examen est ainsi facilité et les douleurs, nausées et vomissements sont supprimés et les céphalées fortement diminuées. L'action de la dihydroergotamine dure à peu près 12 heures. En cas de reprise des symptômes, une deuxième injection peut être nécessaire, dans la soirée du jour de l'examen.

     

Trasplante renal exitoso con protocolo de eculizumab,timoglobulina y belatacept en paciente altamente sensibilizada con síndrome hemolítico urémico atípico por mutación del factor H

Atypical haemolytic uremic syndrome is a disease caused by complement regulation abnormalities that generally progresses to chronic end-stage renal disease with a high rate of recurrence in kidney transplantation and a high risk of graft loss. Anti-complement therapy has improved the prognosis of these patients, achieving disease remission in most cases, increasing the likelihood of a successful kidney transplant and increasing patient and graft survival. Drugs with low risk of induction of thrombotic microangiopathies such as belatacept and mycophenolate have also been used with satisfactory results. We present the case of a young patient at high immunological risk, with atypical haemolytic uraemic syndrome due to factor H mutation, who underwent a successful kidney transplantation with eculizumab, thymoglobulin, belatacept, mycophenolate and steroids, to date preserving excellent graft function without disease recurrence.     

Direct detection of myocardial fibrosis by MRI

Excessive collagen deposition is a major hallmark of cardiac disease. Fibrosis reduces cardiac function and plays a major role in cardiac arrhythmogeneity. Despite the clinical importance, there is no non-invasive technique for direct detection of myocardial fibrosis yet. Ultra short echo time (UTE) MRI has been shown to detect tissues with a fast T₂* signal decay. Collagen has a fast T₂* signal decay compared to myocardium and should therefore be detectable with UTE MRI. This study aims to investigate the use of UTE MRI to detect fibrosis after myocardial infarction without using exogenous contrast. In 7 male Lewis rats either myocardial infarction was created (n = 5) or sham surgery was performed (n = 2). Six weeks after surgery, hearts were isolated and visualized by MRI. Images were acquired with UTE (TE 0.15 ms), to detect tissue with a fast T₂* decay. Acquired conventional images (TE = 6.0 ms) were subtracted from UTE images to maintain only ‘short living signal’ (SLS): tissue with a fast decay. In infarcted hearts, SLS was observed in subtracted images, whereas in control hearts hardly any SLS was detected. Subtracted images were cross-referenced with histology and showed that the SLS area observed with UTE MRI corresponded to the collagen-rich areas observed in histology. Normalized SLS areas correlated well with the normalized collagen-rich areas; r = 0.7, p = 0.002. We show for the first time that UTE MRI technology can be used for direct detection of post-infarcted fibrosis without the use of contrast agents.     

Multiple venous and arterial thromboses of the gallbladder causing acute cholecystitis. A previously undescribed complication of essential thrombocythemia

Well established complications of essential thrombocythemia are multiple thrombohemorrhagic phenomena in various abdominal organs. We describe the case of a 22 year old man with essential thrombocythemia and thrombosis of the mesenteric and splenic veins as well as cavernomatous transformation of the portal vein. The patient also had a splenic infarction and a subphrenic hematoma. Additionally, he developed signs and symptoms of acute cholecystitis which in turn led to an open cholecystectomy. The gallbladder had a markedly thickened wall due to multiple recent and recanalized thrombi predominantly in subserosal veins. Only a few arteries were occluded by thrombi. A marked vascular proliferation in the subserosal connective tissue mimicking a hemangioma was most likely the result of collateral circulation. There was also a mild acute and chronic inflammatory infiltrate and edema in the lamina propria of the gallbladder. Hyperplasia of interstitial cells of Cajal in the lamina propria and between smooth muscle cells and proliferation of nerve trunks in the subserosal connective tissue adjacent to the thrombosed veins and arteries was also noted. To our knowledge this unique gallbladder thrombotic complication of essential thrombocythemia has not been previously reported.