Determination of the impurity profile of adenosine by means of ion-pair reversed-phase chromatography.

Production processes of adenosine include condensation of ribose and adenine by means of chemical or biochemical processes, as well as fermentation. Nowadays, adenosine is commonly produced by alkaline hydrolysis of yeast ribonucleic acid, often in the presence of calcium or lead ions, followed by chromatographic separation of the obtained nucleosides adenosine, cytidine, guanosine and uridine. The current Ph. Eur. monograph for adenosine describes a TLC method for determination of related substances that limits the impurities to 1 per cent. To ensure the quality of adenosine, it is proposed to replace the TLC method by a more sensitive and selective HPLC method, in accordance with the current policy for control of impurities as defined by the Ph. Eur. Commission. An HPLC separation system, originally proposed by the USP, using ion-pair reversed-phase chromatography in combination with tetrabutylammonium hydrogen sulphate as an ion-pair reagent, has been examined for its suitability to limit guanosine, inosine, uridine and adenine. This article describes the experiments as regards the choice of the most suitable commercial column to obtain an appropriate separation, the column temperature, the establishment of a relevant system suitability criterion, and the determination of correction factors for the individual impurities.

Indications for pneumonectomy. Pneumonectomy for benign disease.

A wide variety of nonmalignant diseases of the lung require pneumonectomy. Pneumonectomy for inflammatory lung disease is frequently associated with high morbidity rates, and the frequencies of postpneumonectomy space empyema and bronchopleural fistula are high. It is essential to treat underlying infections prior to surgery in an effort to minimize the sputum production, maximize the patient's nutritional status, minimize the chance for intraoperative spillage, and decrease the risk of postoperative bronchopleural fistulas and postpneumonectomy space empyemas. Despite the challenges of performing a pneumonectomy for inflammatory diseases, cure rates for MDR-TB, MOTT infections, and fungal disease, including invasive fungal disease, are excellent. Pneumonectomy for trauma is associated with very high mortality, and efforts should be made to avoid pneumonectomy if possible. Pneumonectomy for other benign conditions is unusual.

Perforation of the right ventricle: a complication of blind placement of a chest tube into the postpneumonectomy space.

We were asked to review a case from an outside hospital in which there was inadvertent perforation of the right ventricle during the percutaneous placement of a chest tube. We present the case in the hopes that by doing so, others will avoid such a complication in the future. After reviewing the case, it appeared that the complication occurred because the physician was not knowledgeable about the anatomy of the postpneumonectomy space and the physician failed to use the safest procedure in placing the tube.

[Somatosensory potentials in hemiparkinsonism]. / Potencjaly somatosensoryczne w polowiczym parkinsonizmie.

For a trial of explaining of the occurrence of sensory symptoms in Parkinson's disease evoked somatosensory potentials were studied in 10 patients with hemiparkinsonism and paraesthesiae on the side of the parkinsonian signs. Somatosensory evoked potentials were compared after stimulation of the median nerve on the side of parkinsonian signs with those obtained after stimulation of this nerve on the asymptomatic side. No statistically significant differences were found in the latency of various components of the evoked potentials between both sides of the body. Only slight differences were observed in the morphology of the evoked potentials which were difficult for statistical interpretation.

Analysis of evoked lumbosacral potentials in man.

Surface electrodes have been used to record potentials evoked in the lumbosacral region of 15 healthy volunteers after tibial nerve stimulation. By monitoring the M waves and H reflexes in the triceps surae muslces and by comparing the responses recorded over the roots with those over the lower cord, it was possible to identify the neural substrates responsible for several of the components in the responses. The findings are compared with those of previous studies in man and in other mammalian preparations.