The effect of physeal traction applied to the triradiate cartilage on acetabular growth

Summary Physeal distraction was applied with an external fixator to the triradiate cartilage of dogs with the aim of increasing the capacity of the acetabulum. The force was continued for from 2 to 6 weeks and the consequent changes were evaluated with regard to function and structure by radiography and microscopy. The distraction, without producing epiphysiolysis and destruction of the cartilage, resulted in expansion of the pelvic bones. The depth and volume of the acetabulum were increased, but the acetabular angle was decreased. Distraction also caused proliferation of the lacunar cells and the number of mammillary processes in the cartilage columns increased. Distraction can therefore be applied to the triradiate cartilage to enlarge the capacity of the acetabulum without producing epiphysiolysis.

---

Résumé Dans cette étude une distraction a été appliquée sur le cartilage en Y. Douze chiens bâtards, âgés de 2.5 à 4 mois, ont été utilisés pour cette expérimentation. Une force de distraction de 80 Newton a été appliquée d'emblée sur le cartilage en Y. L'application de cette force a été poursuivie sur les animaux pendant 2, 4 ou 6 semaines. A la fin de cette période, les changements de la cavité cotyloïde et du cartilage en Y ont été évalués sur le plan fonctionnel, morphologique, radiologique et histopathologique Aucune altération fonctionnelle n'a été mise en évidence dans les groupes opérés par rapport au groupe de contrôle. On a observé que la distraction a déterminé une expansion massive de l'ilion, du pubis et de l'ischion. Sur les hanches de contrôle la profondeur de la cavité cotyloïde a été évaluée à 13.5 mm, le volume à 1.96 cc et l'angle de la cavité cotyloïde à 29.9°. Après distraction ces valeurs ont été respectivement de 14.4 mm, de 2.10 cc et de 25.7°. La distraction entraîne donc un accroissement de profondeur et de volume de la cavité cotyloïde, mais inversement une diminution de l'angle de cette cavité. Ces résultats montrent que la distraction détermine une prolifération des cellules lacunaires et un accroissement des processus mammaires dans les colonnes du cartilage en Y. Ils montrent également qu'elle peut augmenter la taille de l'acetabulum.

     

Prenatal diagnosis by isoenzymic differentiation of Treacher Collins' syndrome induced by retinoids in rats

A series of branchial arch malformations was induced in 618 embryos from 72 pregnant rats by a single intraperitoneal injection of 10 mg/kg etretinate at 8.5 days of gestation. The litters developed several malformations, including microtia, low set and dorsally placed outer ears, defective middle ear ossicles, short cochleas, defectively differentiated Meckel's cartilages, micrognathia, rudimentary malar bones, lateral facial clefts, fistulas and skin tags, all of which were similar to Treacher Collins' syndrome in man. The defects were accompanied by a pathological differentiation pattern of various isoenzymes in maxillary and mandibular processes. These isoenzymes could be detected in amniotic fluid from the 9th to the 20th days of pregnancy and showed a pathological differentiation pattern here as well. We conclude that a teratogenically induced syndrome affecting the first and second branchial arches is accompanied by a pathological differentiation pattern that can be traced by determinations of isoenzymes in the branchial arches as well as in amniotic fluid.     

Blood cell trauma and postoperative bleeding: comparison of bubble and membrane oxygenators and observations on coronary suction

Blood cell trauma and postoperative bleeding were studied in 96 patients following coronary artery bypass grafting, with bubble oxygenator used in 47 cases and membrane oxygenator in 49. The haemocompatibility of membrane oxygenators was superior to that of the bubble type, as reflected by less haemolysis, better preservation of platelet function, less release of betathromboglobulin and less degranulation of neutrophil granulocytes. Coronary suction contributed to haemolysis, but did not affect platelet or granulocyte function. Fibrinolysis, postoperative blood loss and need for blood transfusion did not differ between the bubble and membrane oxygenator groups.     

Positron Emission Tomography in Tumor Diagnosis and Treatment Follow-Up

The technique of positron emission tomography (PET) is described. PET is an in vivo imaging and quantitative technique which allows the visualization of various functional and biochemical parameters. PET is a tracer technique in which bioactive tracer substances are labelled with short-lived positron emitting radionuclides. The most important of these are ¹⁵O, ¹³N, ¹¹C and ¹⁸F with decay times ranging from 2 min to 2 h. The radiolabeled substance is injected intravenously and the distribution, uptake and binding are registered externally with the PET camera using of the order of 4 000 small detectors. The camera produces simultaneously 15 tomographic slices in which the absolute concentration of the tracer substance can be measured. Using a dynamic imaging sequence starting after the injection of the tracer, the dynamics of the tracer uptake is recorded and can be used to deduce functional parameters, such as perfusion flow, tracer distribution, binding to receptor or enzyme systems, etc. depending on the choice of tracer substance. The great versatility of PET and its potential of direct noninvasive study of tumor function will make it a very important clinical and research tool in oncology. With the choice of substances selective for a certain aspect of a tumor's biochemistry the potential opens for a better diagnosis, improved differential diagnosis and, especially with the use of metabolic tracers, an improved possibility to evaluate the response to treatment.     

Destructive changes of the spine in magnetic resonance imaging

Summary Twenty-nine patients were examined by magnetic resonance imaging for various lesions of the spine. The results of these scans were compared with those of plain radiographs, computertomographs, and radionuclide bone scans. The findings were substantiated by intraoperative or histological findings in 18 cases. The MRI scans proved to be very sensitive in the detection of a wide spectrum of morphological changes of the bone marrow of vertebral bodies. Characteristic changes of the signal patterns for inflammatory and tumorous lesions were not observed. The differentiation of these lesions will presently continue to have to be based on morphological criteria.No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this study. No funds were received in support of this study     

Activity-dependent Decay of Early LTP Revealed by Dual EPSP Recording in Hippocampal Slices from Young Rats

The early maintenance of long-term potentiation (LTP) was studied in the CA1 region of hippocampal slices from 12- to 18-day-old rats in a low-magnesium solution (0.1 mM). The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) and N-methyl-D-aspartate (NMDA) receptor-mediated components of the field excitatory postsynaptic potential were estimated in parallel using early and late measurements of the composite potential. At the normal test stimulus frequency of 0.1 Hz, LTP was seen initially as a predominant increase in the AMPA component, but converted, via a substantial decay of this component and a gradual growth of the NMDA component, into nearly equal changes of the two components. Interrupting the test stimulation for 10 min, changing the test stimulus frequency to 1/60 Hz after LTP induction, or using a test stimulus frequency of 1/60 Hz during the entire experiment significantly reduced the decay of the potentiation of the AMPA component while enhancing the potentiation of the NMDA one. The ratio between the magnitudes of the two excitatory postsynaptic potential (EPSP) components showed a decaying time course that was independent of the manipulations used. Application of the NMDA antagonist D(-)-2-amino-5-phosphonopentanoic acid (50μM) after LTP induction stabilized the LTP of the AMPA component until washout was started. On the other hand, the phosphatase inhibitor okadaic acid (1 μM) resulted in decay of the potentiation of both EPSP components back to around baseline and altered the time course of the ratio between the components. Our results show that the early maintenance of LTP is controlled in an activity-dependent and NMDA-dependent manner. This process accelerates the decay of LTP of both AMPA and NMDA components in parallel, suggesting that it is similar to homosynaptic long-term depression, although it operates at the normal test stimulus frequency. The data support a scenario in which LTP ensues as a selective AMPA receptor modification and subsequently converts to another modification, possibly a presynaptic one.