Determination of cadmium, zinc, copper, chromium and arsenic in crude oil cargoes.

One of the sources of trace heavy metal elements in air is emission by the oil industry, either directly through stack emissions from refineries or indirectly from emissions of combustion of hydrocarbons. Emission estimates are based mainly on the trace metal content of the crude oil processed. From a literature study carried out at the beginning of the 1990s it became clear that data on the trace metal content of crudes were scarce and showed a very large scatter. For this reason a measurement programme to assess the occurrence and concentrations of a number of trace metals, i.e. Cadmium (Cd), Zinc (Zn), Copper (Cu), Chromium (Cr), and arsenic (As), in crudes which are regularly processed in the Netherlands, was set up. By drafting strict sampling protocols and by constructing a special sampling device, as many as possible of the additional contamination sources were avoided. The study suggests that sample contamination may explain a significant amount of the scatter and some of the high concentrations reported in the literature for certain metals. The measured variation in the concentrations of Cd, Zn, and Cu is thought to be due to associated water and/or sediment particles from the producing wells or that picked up during transport. The greater consistency in our measurements for Cr and As suggests that these metals are predominantly associated with the hydrocarbon matrix. Based on the results of this work, it can be concluded that emissions of Cd, Zn, Cu, Cr, and As by the oil industry in the Netherlands are most probably significantly lower than hitherto assumed.

Anastomotic pseudoaneurysm after aorto-coronary bypass grafting.

A patient with a pseudoaneurysm at the site of the distal anastomosis of a saphenous vein coronary bypass graft is described. The aneurysm was resected. To our knowledge this is the first report of this complication after coronary bypass surgery.

A comparative study on enzymatic data from myocardial biopsies and cardiac function in patients who underwent cardiac surgery.

Twenty-three patients underwent cardiac surgery for valve replacement, valve reconstruction, aorto-coronary bypass grafting, aneurysmectomy or combinations of these. Excised cardiac tissue was obtained from left ventricular (LV) papillary muscle (17 patients), LV outflow tract (3 patients), or LV aneurysms (3 patients). A total of 34 myocardial samples, collected from excised cardiac tissue, were analysed for creatine kinase (CK), CK-isoenzymes, cytoplasmic and mitochondrial isoenzymes of aspartate aminotransferase (cAST and mAST, respectively), and lactate dehydrogenase (LDH) isoenzymes. Myocardial CK activity correlated positively with preoperative LV ejection fraction (p less than 0.001), negatively with the preoperatively measured extent of LV wall motion abnormalities (p less than 0.001), and negatively with preoperative LVEDP (p less than 0.02). Myocardial CK activity was negatively correlated with preoperative validity class (p less than 0.005). However, no correlation existed between myocardial CK activity and postoperative validity. Excluding the biopsies from LV aneurysms, myocardial CK activity was positively correlated with the fraction H-subunits in LDH (p = 0.02), and was negatively correlated with the fraction mAST in total AST (p less than 0.005). While cAST activity was proportional to CK activity in the biopsies from VL papillary muscle and LV outflow tract, mAST activity declined only with 2.4 +/- 1.2% per 10% fall of CK. The increase of mAST/cAST ratio with decreasing CK, together with the decrease of LDH-H/LDH and CK-M/CK ratios with decreasing CK, indicated the presence of an adaptation process in a myocardium with low CK activity rather than a process of necrosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Isolated chylopericardium due to lymphangiomatous dysplasia of the thymus.

In this paper we present the case of an 18-year old asymptomatic woman whose routine chest radiograph revealed an enlarged cardiac silhouette which was caused by a chylopericardium due to a lymphangioma of the thymus.