Acquired supravalvar membranous stenosis of the left atrioventricular valve

Acquired supravalvar membranous stenosis of the left atrioventricular valve developed in a nine year old boy with atrioventricular discordance. The supravalvar membrane had not been present when a partial annuloplasty was performed on the left atrioventricular valve eight years before. The stenosis was relieved by operative excision of the membrane.     

Lack of Major Effects on Mouse Brain Adenosine A1 Receptors of Oral Carbamazepine and Calcium Antagonists

Interaction with adenosine A1 receptors is a possible contributory mechanism to the anticonvulsant effects of carbamazepine (CBZ) and the dihydropyridine calcium antagonists. We measured the binding of [3H]cyclohexyladenosine to adenosine A1 receptors in mouse brain stem, cerebellum, and cortex after oral administration of nifedipine, nimodipine (NMD), and CBZ for 7 days and compared the results with binding in control mice. Equilibrium dissociation constant (Kd) and receptor numbers (Bmax) were calculated using Scatchard and saturation isotherm analyses. Mean Kds (SEM) in control brain stem, cerebellum, and cortex were 2.09 (0.31), 2.39 (0.2), and 3.12 (0.28) nM, respectively. Results of Bmax for the same areas were 188 (26), 280 (24), and 449 (54) fmol/mg protein. Nifedipine (p less than 0.005) and NMD (p less than 0.02) raised the Kd of A1 receptors only in the cerebellum, and CBZ increased cerebellar Bmax (p less than 0.05). These minor effects on A1 receptors in CF1 mice, when given in doses previously shown to have anticonvulsant properties in these animals, do not suggest that alteration in A1 receptor activity is an important mechanism for the anticonvulsant effects of these drugs.     

Revascularization of the renal artery in renovascular hypertension with progressive renal insufficiency

Sixteen patients underwent surgical treatment for severe renovascular hypertension with rapidly progressive renal failure. These patients were assessed preoperatively with the measurement of serum creatinine and blood-urea levels (means 271 +/- 204 mumol/l and 15.6 +/- 10.3 mmol/l respectively), and renal clearances. 5 patients underwent aorto-renal bypass (bilateral in one case) and 11 patients were treated by autotransplantation of the kidney. Operative mortality was 6.2%. Early results were assessed at 1 and 6 months postoperatively. Renal function was normal in 8 patients, improved in 5 (p less than 0.05), unchanged in 1 and worse in 1 by aorto-renal bypass thrombosis. At long-term with a minimum follow-up of 12 months (mean 31 +/- 12 months), the initial improvement in renal function remained steady in 12 patients whilst 1 patient has gone on to hemodialysis. At middle and long-term, 81% of the patients were normotensive without medication or had improved blood pressure (p less than 0.001). These good results confirm the reversibility of renal ischemic lesions and support an aggressive attitude towards the use of revascularization in the surgical treatment of such patients with renovascular hypertension and renal failure.     

Automatic algorithm for correcting motion artifacts in time-resolved two-dimensional magnetic resonance angiography using convex projections.

Time-resolved contrast enhanced magnetic resonance angiography (MRA) may suffer from involuntary patient motion. It is noted that while MR signal change associated with motion is large in magnitude and has smooth phase variation in k-phase, signal change associated with vascular enhancement is small in magnitude and has rapid phase variation in k-space. Based upon this observation, a novel projection onto convex sets (POCS) algorithm is developed as an automatic iterative method to remove motion artifacts. The presented POCS algorithm consists of high-pass phase filtering and convex projections in both k-space and image space. Without input of detailed motion knowledge, motion effects are filtered out, while vasculature information is preserved. The proposed method can be effective for a large class of nonrigid motions, including through-plane motion. The algorithm is stable and converges quickly, usually within five iterations. A double-blind evaluation on a set of clinical MRA cases shows that a completely unsupervised version of the algorithm produces significantly better rank scores (P=0.038) when compared to angiograms produced manually by an experienced radiologist.     

Triplet morbidity and mortality in a large case series.

OBJECTIVE: A significant increase in the triplet birth rate has occurred recently. This rise is of concern, as these infants are historically reported to be at risk of adverse outcome. Thus, we examined the outcome of triplet births in a large contemporary case series. STUDY DESIGN: Since 1993, detailed clinical data have been collected on all patients admitted to our Neonatal Intensive Care Unit. We retrospectively analyzed this database to examine triplet outcome. RESULTS: A total of 51 consecutive sets of triplets were born over a 9-year period. The mean birth weight for triplets was 1789+/-505 g, mean gestational age was 32.6+/-2.7 weeks, with discordancy present in 17.6% of neonates. Complications of prematurity were infrequent. Triplet survival to discharge was 96%. CONCLUSIONS: This large contemporary case series of triplets demonstrates excellent survival with low associated morbidity. These data suggest that there may no longer be medical justification for offering selective fetal reduction to parents with triplet pregnancies.     

The relevance of therapeutic drug monitoring in plasma and erythrocytes in anti-cancer drug treatment.

Therapeutic drug monitoring generally focuses on the plasma compartment only. Differentiation between the total plasma concentration and the free fraction (plasma water) has been described for a number of limited drugs. Besides the plasma compartment, blood has also a cellular fraction which has by far the largest theoretical surface and volume for drug transport. It is with anti-cancer drugs that major progress has been made in the study of partition between the largest cellular blood compartment, i.e., erythrocytes, and the plasma compartment. The aim of the present review is to detail the progress made in predicting what a drug does in the body, i.e., pharmacodynamics including toxicity and plasma and/or red blood cell concentration monitoring. Furthermore, techniques generally used in anti-cancer drug monitoring are highlighted. Data for complex Bayesian statistical approaches and population kinetics studies are beyond the scope of this review, since this is generally limited to the plasma compartment only.