Hypokalaemia in healthy volunteers after single and multiple doses of formoterol or salbutamol.

A specific beta(2)-adrenoceptor-mediated effect, hypokalaemia, was studied in healthy volunteers after single as well as multiple dosages of the long-acting agonist formoterol and the short-acting agent salbutamol. The purpose of the study was to test with simple methodologies if rapidly induced tachyphylaxis for this well known systemic effect can be shown and if it will then be more pronounced for the long-acting compound. Hypokalaemia induced by inhalation of, respectively, 72microg formoterol and 1200microg of salbutamol was studied before and after 1 week of medication. Potassium-time curves were described by a biexponential equation and also analysed with a deconvolution technique. Both drugs induced a statistically significant hypokalaemia, the duration of this effect being considerably shorter for salbutamol than for formoterol (p < 0.05 with both methods of analysis). After multiple doses for 1 week, both maximal hypokalaemia and the area under the curve of the hypokalaemic effect had decreased after inhalation of formoterol (p < 0.05) but not after inhalation of salbutamol.It was concluded that plasma potassium as an effect measurement can be used to study in a simple but reproducible way differences of pharmacological interest between various beta(2)-adrenoceptor agonists.

Staging of ampullary and pancreatic carcinoma: comparison between endosonography and surgery.

BACKGROUND: The aim of the study was to update our previously published data on the clinical TNM staging of ampullary and pancreatic carcinoma by endosonography. METHODS: Endosonography was performed in 70 patients with pancreatic cancer and in 32 patients with ampullary carcinoma. TNM staging was carried out before surgery and compared with findings of histology and/or surgery. RESULTS: Endosonography was accurate in staging the depth of tumor invasion. Early-stage carcinomas could be distinguished from advanced cancers. Nonresectability was accurately assessed on the basis of vascular involvement using real-time ultrasound. Tumor compression due to peritumoral pancreatitis and direct tumor invasion into the base of the mesocolon could not be diagnosed by endosonography. The overall accuracy in tumor staging for pancreatic and ampullary carcinomas was 83.6% and 84.4%, respectively. Endosonography was accurate in diagnosing regional lymph node metastases but not accurate in defining nonmetastatic lymphadenopathy and distant metastases. CONCLUSION: Endosonography was accurate in staging tumor stage and lymph node metastases. Minimally invasive methods of resection for superficial ampullary cancers should be based on endosonography staging.

Endosonography of groove pancreatitis.

Groove pancreatitis is a rare form of chronic pancreatitis. Distinction between pancreatitis and pancreatic carcinoma is often difficult. Two cases of groove pancreatitis diagnosed by endosonography are described. A hypoechoic pattern between the duodenal wall and pancreas was clearly imaged in both patients. Narrowing of the second part of the duodenum and evidence of bile duct obstruction were also found. The endosonographic diagnosis was confirmed either by surgery or follow-up examination.

Endosonography in the clinical staging of esophagogastric carcinoma.

Endosonography (ES) was preoperatively performed in 113 patients with esophageal carcinoma (group 1) and in 84 patients with gastric carcinoma (group 2). Results of imaging and histology of resected specimens were correlated according to the new (1987) TNM classification. ES was accurate in assessing the depth of tumor infiltration. Overall accuracy of ES for group 1 was 89% and for group 2 83%. Early carcinomas could be distinguished from advanced cancers. ES was accurate in diagnosing lymph node metastases (sensitivity group 1 95% and group 2 87%) but less accurate in defining inflammatory changes of lymph nodes (specificity group 1 50% and group 2 48%). The incidence of lymph node metastases increased with progression of the depth of tumor infiltration. ES is not accurate for staging distant metastasis due to the limited penetration depth of ultrasound. Thus, additional transcutaneous ultrasound or computed tomography is necessary. Routine ES-guided cytology of lymph nodes may further enhance the diagnostic accuracy of ES.