Cerebrovascular reserve in patients with carotid occlusive disease assessed by stable xenon-enhanced ct cerebral blood flow and transcranial Doppler.
We report the clinical and laboratory data in 3 patients who presented with severe hypercalcemia (corrected serum calcium > or = 14 mg/dL) and review the pertinent literature on milk-alkali syndrome.
149 patients after open-heart surgery (correction of heart valve defects and aortocoronary bypass surgery) have been examined. Volume expansion was performed by rapid intravenous infusion of 200-800 ml of fluid. Hemodynamic parameters were studied by direct methods. Patients with initially high heart chamber filling pressure were subject to forced diuresis (bolus intravenous injection of 1-2 mg lasix), the changes in hemodynamic parameters were registered with gradual fluid excretion. Left ventricular function curves were plotted in the coordinates: stroke heart work or stroke index--left ventricular end diastolic pressure. A down slope of the Starling curve was registered in 34% of patients, which was indicative of heart failure, volume overload of the myocardium or was prognostically unfavourable as to the onset of heart failure. The values of left ventricular diastolic pressure, when a down slope was registered, varied from 3-5 to greater than or equal to 20 mm Hg, depending on myocardial contractility and diastolic function. Peripheral vasodilation was the earliest sign of the myocardial volume overload. Volume load test proved to be ineffective in 27% of patients and insufficiently effective in 13.7% of patients.
In vivo absorption studies were carried out in human volunteers to evaluate whether microcrystalline chitosan (MCCh) granules would be gastro-retentive. Furosemide, which is site-specifically absorbed from the upper gastrointestinal tract, was used as model drug. The rate of release of furosemide in vitro could be prolonged by increasing the molecular weight (M(w)) or amount of MCCh (150 to 240 kDa; 80 to 95%) in the granules, and also by addition of acidic excipients to the formulations. No marked changes in the in vivo absorption rate (t(max)) were noted, but the amounts of furosemide absorbed (AUC(0- infinity ) and C(max)) decreased as the in vitro release rate decreased, although this was not statistically significant in the case of AUC. The highest AUC(0- infinity ) (3050 micro g l(-1) h) for furosemide (40 mg) was achieved with granules containing 80% MCCh of 150 kDa M(w). With MCCh of 240 kDa M(w) AUC(0- infinity ) was 1890 micro g l(-1) h. This kind of pharmacokinetic profile of furosemide suggests that the gastric retention time of the granules is too short in relation to the release rate, and a large amount of the drug passes its "absorption window" before being released. The in vivo study produced no evidence that the chitosan formulations studied can be used as mucoadhesive gastro-retentive drug delivery systems. The results of in vitro mucoadhesion studies did not predict the results of in vivo studies.
To identify the frequency of acute kidney injury in patients receiving angiotensin-converting enzyme inhibitor therapy in postoperative pediatric cardiac surgical patients and to identify risk factors for acute kidney injury in this patient population.
A loss-of-function polymorphism of the human tissue kallikrein (TK) gene (R53H) induces a major decrease in enzyme activity. Inactivation of the TK gene in mice causes a defect in tubular calcium (Ca) reabsorption. Therefore, this study investigated the Ca phenotype of carriers of the 53H allele. In a crossover study, 30 R53R homozygous and 10 R53H heterozygous young white male individuals were randomly assigned to two 7-d low-Ca diets (10 mmol/d) associated with either a low-sodium (Na)/high-potassium (K) diet or a high-Na/low-K diet to modulate TK synthesis. On the seventh day of each diet, the participants were studied before and during a 2-h infusion of furosemide that functionally excludes the thick ascending limb and increases Ca delivery to distal tubular segments. Urinary kallikrein activity was 50 to 60% lower in R53H participants than in R53R participants. Adaptation of urinary Ca excretion to the contrasted Na/K diets was unaffected in R53H participants. By contrast, R53H participants after furosemide infusion had significantly lower serum ionized Ca concentrations than did R53R participants (P < 0.0001) and tendency toward nonsignificantly higher urinary Ca excretions than did R53R participants (P = 0.14). These effects were more marked under low-Na/high-K diet. Despite nonsignificant differences in urinary Ca excretions between the two groups, these results suggest in R53H individuals an increase in Ca reabsorption in the thick ascending limb under baseline conditions that counteracts a distal tubular defect that is revealed by furosemide infusion. In humans as in mice, TK thus may act as an intrarenal modulator of Ca reabsorption.
Three of 5 control animals and 2 of 10 stented animals has strictures. In the unstented study group, all 5 animals had a nonobstructing dilation at the site of endoureterotomy. This was corroborated by a normal furosemide washout renal scan in all 3 animals so tested.