Uptake and excretion of vecuronium bromide and pancuronium bromide in the isolated perfused rat liver

Using the isolated perfused rat liver preparation, the disappearance from the perfusate and the excretion in the bile of vecuronium bromide and pancuronium bromide and their metabolites were followed for 2 h after the addition of 1 mg of either drug to the perfusate. In addition, the rate of change of the hepatic content of these two compounds was calculated by serially subtracting the amount of the compound and the metabolites in the bile and in the perfusate from the dose of drug added to the perfusate. It was found that, whereas the concentration of pancuronium in the perfusate declined slowly and monoexponentially, vercuronium concentration in the perfusate declined rapidly in a biexponential manner. No metabolites of either drug were detected in the perfusate. Approximately 40% of the injected dose of vecuronium was excreted in the bile as unchanged vecuronium and another 30% as the 3-hydroxy metabolite. No other metabolites of vecuronium were found in the bile. In total only about 7% of pancuronium (unchanged) was collected in the bile by the end of the experiment. It is concluded that, in comparison to pancuronium, the rat liver takes up large amounts of vecuronium rapidly, half of which is eliminated as unchanged vecuronium and half as the 3-hydroxy derivative. A small amount of vecuronium or its 3-hydroxy metabolite is returned to the perfusate from the liver. Some possible mechanisms underlying these differences are discussed.     

Cutaneous abnormalities in uremic patients

94 uremic patients, 68 on regular hemodialysis treatment (RHT) and 26 on chronic ambulatory peritoneal dialysis (CAPD), were followed for up to 20 months in search of dermatological manifestations. 79% of RHT and 76% of CAPD patients had some kind of cutaneous lesion. The most characteristic features of cutaneous involvement in RHT and CAPD patients were: cutaneous xerosis, pruritus, infectious manifestations and disorders of pigmentation. In 4 RHT patients, precancerous and cancerous manifestations were also observed.     

Ultrasonography of nodular and infiltrative lesions of the skin and subcutaneous tissues

Ultrasonography with high-frequency probes was performed on 80 dermatological patients carrying palpable lesions of the skin. The case list included hemo- and lymphangiomas (16 cases), cysts (13 cases), Kaposi sarcomas (9 cases), and panniculitis (20 cases). All lesions underwent open biopsy and histological examination. Ultrasound yielded technically adequate images in 74/80 cases (93%). Angiomas appeared as multiple transonic cavities separated by hyperechoic septa; cysts were usually echo free or weakly echogenic, with smooth outlines. Kaposi sarcomas corresponded to superficial hypoechoic nodules with blurred margins, while panniculitis appeared as a diffuse thickening of the subcutaneous space. When acute inflammation was present, as in most cases of erythema nodosum, a nonhomogeneous hypoechoic pattern was found.     

Simultaneous aortoiliac reconstruction and renal transplantation: is it safe?

A 54-year-old man with an aortoiliac aneurysm and renal failure due to renal artery thrombosis was placed on a transplantation waiting list. The aneurysm had a 3 cm diameter and, therefore, did not require aortoiliac reconstruction, while its evolution was followed by ultrasound color-doppler every six months. The aneurysm was stable and two years later, when a cadaver kidney became available, a preoperative ultrasound color-doppler showed initial wall dissection. Therefore, an abdominal aneurysmectomy using a standard Dacron bifurcation graft and renal transplantation were successfully carried out. The patient had no associated complications and 24 months after transplantation and aneurysmectomy currently has good renal function and distal pulses. Only 20 cases of simultaneous aortoiliac reconstruction and renal transplantation have been reported in the literature. The excellent results of our case and those reported in the literature prove that patients who have both severe aortoiliac disease and end-stage renal failure can safely undergo simultaneous aortic reconstruction and renal transplantation. However, the atherosclerosis in these patients is a generalized process, so that in the pretransplant protocol special attention should be paid to detecting coronary artery atherosclerosis. In fact, coronary artery disease may have a priority claim to therapy because of the high risk of myocardial infarction. Our own policy is to put the patient back on the waiting list for renal transplantation after treatment for coronary artery disease. Furthermore, considering that the management for aortoiliac disease and kidney failure is safe in both simultaneous and staged cases, we think that the real issue is whether or not these patients with coronary atherosclerosis can be candidates for renal transplantation. We believe that each transplant centre has to develop its own general policy for these critically ill patients on the basis of its own experience.     

Melasma and low-energy Q-switched laser: treatment assessment by means of in vivo confocal microscopy

Melasma is an acquired disorder of pigmentation for which several therapeutical options are currently available. Among them, low-energy Q-switched Nd:YAG laser (1,064 nm) has been successfully applied in case series although its long-term efficacy has yet to be proven. In vivo confocal microscopy is a novel imaging technique that permits to explore the skin tissue at a nearly histologic resolution. The aim of our study was to evaluate the laser treatment efficacy by means of confocal microscopy at different time points to elucidate the mechanism of action of the laser and its possible drawbacks. Eight women who presented with melasma on the face were subjected to low-energy Q-switched Nd:YAG laser treatment and then analyzed by means of confocal microscopy. An overall improvement of melasma was noticed clinically and microscopically by means of confocal microscopy. Four cases revealed the presence of dendritic-shaped cells upon confocal microscopy and those patients were the ones presenting with a relapse of the disease. The interpretation of these cells is that they could represent reasonably activated melanocytes. This opens the question whether laser treatment should be modulated to avoid side-effects associated with its use. Confocal microscopy has emerged as an excellent tool for a better understanding of the changes occurring during laser treatment.     

Angioplasty of atherosclerotic and fibromuscular renal artery stenosis: time course and predicting factors of the effects on renal function

The effects of percutaneous transluminal renal angioplasty (PTRA) on the renal function of stenotic kidneys are usually assessed by evaluating the changes in serum creatinine, which is quite a rough indicator of glomerular filtration rate (GFR). In 27 hypertensive patients with 19 atherosclerotic and 11 fibromuscular significant renal artery stenoses, we investigated with renal scintigraphy the short-term (5 days) and long-term (10 months) effects of a technically successful PTRA (in seven cases combined with a stent implantation) on GFR of the stenotic and contralateral kidneys; these measurements were combined with those of plasma renin activity (PRA) and of angiotensin II (AII). We found that in short-term studies after PTRA GFR rose from 29.7 +/- 3.5 to 34.6 +/- 3.1 mL/min and from 36.9 +/- 4.0 to 45.1 +/- 4.3 mL/min, respectively, in atherosclerotic and fibromuscular poststenotic kidneys. In long-term studies GFR further and significantly increased, to 37.8 +/- 3.2 mL/min in the former group, whereas it stabilized in the latter group (46.0 +/- 3.6 mL/min). In patients with fibromuscular stenosis these changes in GFR were associated with clear-cut reductions in blood pressure (BP), PRA, and AII; these decrements also occurred in patients with atherosclerotic stenosis but to a much lesser extent. We also found that in short- and long-term studies the percent of PTRA-induced increments of GFR in the poststenotic kidneys were inversely correlated with the baseline values of GFR. In addition, the absolute and percent increments of GFR were positively correlated with the basal levels of AII. Thus the time course of the improvement in GFR after angioplasty may differ in kidneys, depending on the etiology of the stenosis, in that in those with fibromuscular stenosis it was entirely apparent within a few days whereas in those with atherosclerotic stenosis it required several months to be fully expressed. Also, it appears that the more compromised kidneys are those that benefit most from the dilatation and that AII levels are useful indicators of the possibility that the stenotic kidney will have a favorable functional outcome in terms of restoration of renal blood flow.