Cardiac effects of contrast media in MR angiography: evaluation in an experimental model of myocardial ischemia

RATIONALE AND OBJECTIVES: The authors evaluated the cardiac tolerability of paramagnetic contrast agents for magnetic resonance (MR) angiography in an in vitro model of ischemic rat heart. MATERIALS AND METHODS: The left anterior descending coronary artery was temporarily occluded in a perfused rat heart model to induce cardiac ischemia and reperfusion. A dose of 0.4 mL of gadobenate dimeglumine, of gadopentetate dimeglumine, or of D-mannitol was injected directly into the aorta both during the ischemia and during the reperfusion period. The left ventricular pressure and heart rate were recorded. RESULTS: Myocardial ischemia resulted in decreased cardiac activity, with a reduction in left ventricular pressure and heart rate. A further decrease in cardiac activity was temporarily induced by injection of contrast medium during both the ischemic and early reperfusion phases. Less marked responses were induced by a hyperosmolal solution of mannitol. CONCLUSION: These results suggest that the transient cardiac effects induced by bolus injection of paramagnetic contrast medium may be regarded as the combined effects of the osmotoxicity of the contrast medium solution and the chemotoxicity of the contrast medium molecule.     

Atrial fibrillation after operation for lung cancer: clinical and prognostic significance

BACKGROUND: Atrial fibrillation is a common complication of early postoperative period in lung cancer thoracotomy. Its clinical incidence and short- and long-term impact on overall mortality has never been definitely assessed; moreover, it is unclear whether the arrhythmia represents an independent cardiac risk factor. METHODS: We prospectively studied 233 consecutive patients undergoing operation for lung cancer (170 with non-small-cell lung cancer). Postoperative atrial fibrillation incidence was related to different clinical factors possibly involved in its occurrence and to both short- and long-term survival. RESULTS: Atrial fibrillation occurred in 28 patients (12%) (same percentage in non-small-cell lung cancer); a strong relationship was observed between arrhythmia and age, history of hypertension and associated lymph node resection. The mean hospitalization time was 14 +/- 4 days in patients developing atrial fibrillation and 13 +/- 4 days in those who did not (p = not significant). No difference was observed between the two groups with regard to short- or long-term mortality or to long-term atrial fibrillation recurrences, also when considering the entire population and only non-small-cell lung cancer, separately. CONCLUSIONS: At our institution, early atrial fibrillation occurrence after operation for lung cancer does not show any negative impact on short- and long-term mortality or on recurrence rate.     

Primary lymphoma of the small intestine. Radiographic image of enteroclysis with double-contrast media

The authors retrospectively reviewed the radiographic (double-contrast small-bowel enema) examinations of 20 patients with primitive small intestinal lymphomas. The diagnosis was histologically confirmed in all cases. The technique was very sensitive (100%) in detecting small-bowel abnormalities. On the contrary, a definite differential diagnosis was difficult to make (65%), except for 4 cases of lymphoma complicating celiac disease in which the presence of a nodular pattern and of thickened and irregular mucosal folds seemed to be highly specific. The most difficult differential diagnosis was with Crohn's disease. In all the cases with surgical confirmation (17), disease extent exactly corresponded to that suggested by small-bowel enema. Primitive small intestinal lymphoma is not radiologically distinguishable from secondary involvement during systemic lymphoma. From the analysis of radiological abnormalities, the authors observed that, different from previous reports, severe luminal narrowing was frequent, whereas "aneurysmal" dilatations of intestinal loops were never observed. CT was confirmed as the best technique for staging. Clinical implications of double-contrast enema in the diagnosis of primitive small intestinal lymphomas are discussed; radiographic patterns are reviewed.     

Dibenzo[a,l]pyrene-induced DNA adduction, tumorigenicity, and Ki-ras oncogene mutations in strain A/J mouse lung

Dibenzo[a,l]pyrene (DB[a,l]P), an environmental polycyclic aromatic hydrocarbon, is the most potent carcinogen ever tested in mouse skin and rat mammary gland. In this study, DB[a,l]P was examined for DNA adduction, tumorigenicity, and induction of Ki-ras oncogene mutations in tumor DNA in strain A/J mouse lung. Groups of mice received a single i.p. injection of 0.3, 1.5, 3.0, or 6.0 mg/kg DB[a,l]P in tricaprylin. Following treatment, DNA adducts were measured at times between 1 and 28 days, while tumors were counted at 250 days and analyzed for the occurrence of point mutations in codons 12 and 61 of the Ki-ras oncogene. DB[a,l]P in strain A/J mouse lung induced six major and four minor DNA adducts. Maximal levels of adduction occurred between 5 and 10 days after injection followed by a gradual decrease. DB[a,l]P-DNA adducts in lung tissue were derived from both anti- and syn-11,12- dihydroxy-13,14-epoxy- 11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) and both deoxyadenosine (dAdo) and deoxyguanosine (dGuo) residues in DNA as revealed by cochromatography. The major adduct was identified as a product of the reaction of an anti-DB[a,l]PDE with dAdo in DNA. DB[a,l]P induced significant numbers of lung adenomas in a dose- dependent manner, with the highest dose (6.0 mg/kg) yielding 16.1 adenomas/mouse. In tricaprylin-treated control animals, there were 0.67 adenomas/mouse. Based on the administered dose, DB[a,l]P was more active than other environmental carcinogens including benzo[a]pyrene. As a function of time-integrated DNA adduct levels, DB[a,l]P induced lung adenomas with about the same potency as other PAHs, suggesting that the adducts formed by DB[a,l]P are similar in carcinogenic potency to other PAHs in the strain A/J mouse lung model. Analysis of the Ki- ras mutation spectrum in DB[a,l]P-induced lung tumors revealed the predominant mutations to be G-->T transversions in the first base of codon 12, A-->G transitions in the second base of codon 12, and A-->T transversions in the second or third base of codon 61, concordant with the DNA adduct profile.      

TREATMENT OF PALMOPLANTER HYPERHIDROSIS BY IONTOPHORESIS

Twenty-seven patients with idiopathic palmoplanter hyperhidrosis were treated with Iontotherapy over a one year period. In twenty-four cases there was a good response but maintenance therapy was required every 3-4 weeks.KEY WORDS: Iontophoresis, Palmoplanter hyperhidrosis     

Atypical respiratory complications of dengue fever

In last decade, dengue has emerged as one of the most important vector born disease. With increasing cases, uncommon presentations and complications are now commonly recognized. Here, we report two cases of rare pattern of respiratory involvement in dengue: acute respiratory distress syndrome and bronchiolitis with respiratory failure.     

Decreased expression of phospholipase C-beta 2 isozyme in human platelets with impaired function

Platelets from a patient with a mild inherited bleeding disorder and abnormal platelet aggregation and secretion show reduced generation of inositol 1,4,5-trisphosphate, mobilization of intracellular Ca2+, and phosphorylation of pleckstrin in response to several G protein mediated agonists, suggesting a possible defect at the level of phospholipase C (PLC) activation (see accompanying report). A procedure was developed that allows quantitation of platelet PLC isozymes. After fractionation of platelet extracts by high-performance liquid chromatography, 7 out of 10 known PLC isoforms were detected by immunoblot analysis. The amount of these isoforms in normal platelets decreased in the order PLC- gamma 2 > PLC-beta 2 > PLC-beta 3 > PLC-beta 1 > PLC-gamma 1 > PLC- delta 1 > PLC-beta 4. Compared with normal platelets, platelets from the patient contained approximately one-third the amount of PLC-beta 2, whereas PLC-beta 4 was increased threefold. These results suggest that the impaired platelet function in the patient in response to multiple G protein mediated agonists is attributable to a deficiency of PLC-beta 2. They document for the first time a specific PLC isozyme deficiency in human platelets and provide an unique opportunity to understand the role of different PLC isozymes in normal platelet function.