Coralline hydroxyapatite bone graft substitutes: preliminary report of radiographic evaluation

A new bone graft substitute made by conversion of the calcium carbonate exoskeleton of reef-building sea coral into hydroxyapatite has recently become clinically available. The normal radiographic appearance of two forms of this material is described. In the immediate postoperative period, the exoskeletal architecture of these implants is readily appreciated. With graft incorporation over the ensuing months, their intrinsic structure is gradually lost in association with poor marginal definition. Evolving radiographic findings reflect the biocompatible nature of these implants, which provides the potential for ingrowth of native bone with preservation of the coralline scaffold, resulting in enhanced biomechanical properties.     

Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

The superior laryngeal nerve loop and its surgical implications

Summary Based upon findings from 60 cadavers (120 sides), the incidence of superior laryngeal nerve loop, connecting the cervical sympathetic chain and the superior laryngeal nerve and its branches, the external and internal laryngeal nerve, was 98.3% (118 out of 120 sides). In most cases the loop connected the sympathetic chain and the external laryngeal nerve. The external laryngeal nerve was looped, and not linear as traditionally thought. The loop could be divided into three categories, V-shaped, U-shaped and mixed, and subdivided into 5 types and 17 subtypes according to morphological variation. The loop without exception innervated not only the cricothyroid muscle, but also the thyroid gland. The loop is one of the origins of the thyroid nerve. It seems that for thyroid surgery the loop, when lower in position, should be carefully separated from the superior thyroid vessels before the latter are ligated, in order to preserve a normal nerve supply to the muscle as well as to the part of the gland that remains after surgery.

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L'anse du nerf larynge supérieur, étude anatomique et applications chirurgicales

Résumé La fréquence d'une anse du nerf laryngé supérieur réalisant une anastomose entre la chaine sympathique cervicale et le nerf laryngé supérieur et/ou ses branches (rameau laryngé externe et ingerne), est de 98,3 % (118/120). Ce résultat s'appuie sur l'étude de 60 cadavres. Dans la plupart des cas, l'anastomose se fait entre la chaine sympathique cervicale et le rameau laryngé externe. Ce rameau laryngé externe a un trajet curviligne et non linéaire conformément aux données classiques. Il existe trois catégories d'anses : en "V", en "U" et mixte ; on peut également les subdiviser en 5 types et 17 sous-types en fonction des variations morphologiques. Cette anse innerve constamment non seulement le muscle cricothyroïdien mais aussi la glande thyroïde dont elle fournit une partie de l'innervation. Lors de la chirurgie thyroïdienne, si l'anse est en position basse, les nerfs doivent être soigneusement disséqués et séparés des vaisseaux thyroïdiens supérieurs avant ligature de ces derniers de façon à conserver l'innervation normale du muscle et de la partie restante de la glande.

     

A Predominantly Adrenaline-secreting Phaeochromocytoma

A 61-year-old woman who presented with diabetes, nausea, weightloss and sweating was found to have a phaeochromocytoma secretingadrenaline, with a small amount of N-methyIadrenaline. Therewas no significant increase in noradrenaline secretion. Shewas normotensive, and developed profound hypotension in responseto the -adrenergic antagonist phenoxybenzamine. These featuresare unusual in phaeochromocytoma, but similar features occurredin the very few previous reported cases of pure adrenaline-secretingphaeochromocytoma. We conclude that it is important to identifysuch patients, so that they should not be given -adrenergicantagonist drugs.