[Sequential scintiscanning with 99mTc-HIDA in the study of some aspects of post-operative dynamics of the proximal digestive tract]. / La scintigrafia sequenziale con 99mTc-HIDA nello studio di alcuni aspetti della dinamica post-operatoria del digerente prossimale.

The authors exploited the elective biliary excretion of 99mTc-HIDA at adequate concentrations to afford visibility of intestinal segments more directly wetted by bile in a study of sequential hepatobiliary scintigraphy designed to explore the parts of the duodenum and jejunum that are excluded to the transit of gastrointestinal contents in many surgical procedures involving the proximal digestive tract. They illustrate their case material with several representative examples; these are described in detail to show the validity, usefulness and versatility of the scintigraphic technic under discussion.

[Therapeutic trends in adrenal incidentaloma]. / Orientamento terapeutico nell'incidentaloma surrenalico.

The term incidentally discovered adrenal mass or incidentaloma includes several tumors, mainly benign, involving the adrenal space. From 1983 to 1990, at the 1st Surgical Department of the Careggi Hospital of Florence, 10 patients (8 females and 2 males), with age ranging from 31 to 66 years, were found to have an incidentaloma. The size of the mass ranged from 2 to 10 cms; the left side was interested in 2 cases and the right one in 8 cases. The first diagnostic approach was abdominal ultrasound scanning in 8 out of 10 patients, whereas computerized tomography was the first used in the remaining 2 patients. Overall, all patients underwent CT scanning, while abdominal ultrasound scanning was performed in 9, urography in 2, and MNR in 1. Fine needle aspiration was performed in one case of adrenal cyst both for diagnostic and therapeutic purposes. The Authors suggest a therapeutic-diagnostic program in which cytology, obtained through fine needle aspiration, may have a prominent role in reducing the need for surgical interventions, as it recently happened for thyroid disorders. Although technically more complex compared to thyroid fine needle aspiration, adrenal ultrasound-guided FNA may bring to a better classification of the different adrenal disorders reducing at the same time the need for surgery, which at present has a prevalent diagnostic intent.

Sulfite stimulates the ATP hydrolysis activity of but not proton translocation by the ATP synthase of Rhodobacter capsulatus and interferes with its activation by delta muH+.

Sulfite stimulates the rate of ATP hydrolysis by the ATP synthase in chromatophores of Rhodobacter capsulatus. The stimulated activity is inhibited by oligomycin. The activation takes place also in uncoupled chromatophores. The activation consists in an increase of about 12-15-fold of the Vmax for the ATP hydrolysis reaction, while the Km for MgATP is unaffected at 0.16+/-0.03 mM. The dependence of Vmax on the sulfite concentration follows a hyperbolic pattern with half maximum effect at 12 mM. Sulfite affects the ability of the enzyme in translocating protons. Concomitant measurements of the rate of ATP hydrolysis and of ATP-induced protonic flows demonstrate that at sulfite concentrations of greater than 10 mM the hydrolytic reaction becomes progressively uncoupled from the process of proton translocation. This is accompanied by an inhibition of ATP synthesis, either driven by light or by artificially induced ionic gradients. ATP synthesis is totally inhibited at concentrations of at least 80 mM. Sulfite interferes with the mechanism of activation by delta muH+. Low concentrations of this anion (< or = 2 mM) prevent the activation by delta muH+. At higher concentrations a marked stimulation of the activity prevails, regardless of the occurrence of a delta muH+ across the membrane. Phosphate at millimolar concentrations can reverse the inhibition by sulfite. These experimental results can be simulated by a model assuming multiple and competitive equilibria for phosphate or sulfite binding with two binding sites for the two ligands (for sulfite K1S = 0.26 and K2S = 37 mM, and for phosphate K1P = 0.06 and K2P = 4.22 mM), and in which the state bound only to one sulfite molecule is totally inactive in hydrolysis. The competition between phosphate and sulfite is consistent with the molecular structures of the two ligands and of the enzyme.