[Evolution of post-fracture bone deformities in an infant with hepatic osteodystrophy on Alagille syndrome]. / Evolution des déviations osseuses post fracturaires chez une enfant atteinte d'ostéodystrophie hépatique sur syndrome d'Alagille.

INTRODUCTION: This case report describes the evolution of postfractural axial bone deviations that occurred in a child with hepatic osteodystrophy due to an Alagille Syndrome. Postfractural bone deformities in children trend to spontaneous correction if there is a remaining growth potential. In case of severe hepatic osteodystrophy correlated by liver transplantation, we have observed spontaneous correction of a posttraumatic valgus deformity of the leg, as well as worsening of a diaphyseal femoral bowing. We tried to explain this apparently paradoxal evolution. CASE REPORT: Andrea St. is born in 1984 with multiple malformations corresponding to Alagille Syndrome: ductulus paucity, pulmonary arterial hypoplasia, posterior embryotoxin and "butterfly vertebrae". She has developed a cholostatic icterial and a portal hypertension due to a hepatic cirrhosis which needed an hepatic transplantation at the age of 8 years. Before her transplantation, Andrea St developed postfractural axial bone deviations. At the age of 7 years, she had a tibia valgum of 20 degrees and a femoral bowing of 50 degrees. With the normalization of the metabolism due to the hepatic transplantation, the osteopenia as well the tibia valgum of 20 degrees has been corrected spontaneously up to 8 degrees and there was a worsening of the femoral bowing up to 50 degrees. DISCUSSION: The physiopathology of the hepatic osteodystrophy is not yet perfectly known. Treatment with Vitamin D and Calcium doesn't seem to prevent hepatic osteodystrophy. Salter reported that postfractural bone angulation in children will spontaneously correct itself if on one hand it is not far from the growth cartilage and on the other hand if it is in the same mobility plane than the adjacent articulation. Postfractural diaphyseal bone deformities tend to correct spontaneously if the angulation is less than 20 to 30 degrees. Concerning fractures of the proximal tibia in children, they develop frequently a progressive tibia valgum deformity, even if the fracture was not primary displaced. However we know that all proximal tibial fractures in children don't give residual valgus deformities, and that several postfractural tibia valgum correct spontaneously. This has been explained by a temporary growth acceleration of the medial part of the proximal tibial growth plate. In this case, the femoral bowing worsened. This is explained by the mediodiaphyseal location of the deformation, and the importance of the bone deviation much bigger than the threshold of 20 to 30 degrees that may not be overtaken to hope a spontaneous correction. The evolution of the proximal metaphyseal tibial fracture consisted firstly in a progressive valgus deformation that resolved spontaneously after hepatic transplantation.

Tibial tubercle elevation with bone grafts. A comparative study of autograft and allograft.

We retrospectively investigated the fate of bone auto- and allografts in 64 patients who underwent a tibial tubercle elevation with bone graft. Half of them received an autograft and the other half, an allograft that had been processed and freeze-dried. The two groups had similar preoperative characteristics concerning age, sex and pathology. Roentgenograms were reviewed by three independent observers and scored for fusion, resorption and collapse. Clinical charts were analysed for different variables. The overall radiological score for both groups did not differ statistically. Comparison of graft fixation with one or two screws demonstrated more bone resorption in the case of a single-screw fixation. In such a case, the occurrence of a preoperative tubercle fracture had a significant adverse influence, due to a less stable fixation. From the clinical charts review, only the mean stay at hospital was significantly shorter when an allograft was performed. A bone allograft appears to be suitable to maintain an osteotomy but requires a more careful surgical technique fixation to obtain a similar result to an autograft.

Organizational and investigational aspects of bone banking in Belgium.

Our experience with the bone banking methodology that we have used over the last years is reported. The technical and investigational aspects of the procurement, storage and treatment of the donor bone and related tissues are presented. For different purposes, we have prepared sterile and nonsterile procured implants. Appropriate donor selection and sterility controls remain the two major concerns of bone banking activities.

Effects of intravascular volume expansion on lung fluid balance in a canine model of septic shock.

We tested the early effects of endotoxin on both the permeability of capillary membranes and microvascular pressure. One group of dogs (n = 8) were fluid loaded (30 ml/kg dextran-40) after having been subjected to a 2-h Escherichia coli endotoxin infusion (0.25 micrograms/kg X min). A second control group of animals (n = 6) was submitted to a similar (25 ml/kg) volume loading over an equivalent 30-min period. We estimated extravascular lung water (EVLW), calculated the effective pulmonary capillary pressure, and determined the alveolar-capillary filtration coefficient (Kf) after volume loading. Only the septic animals consistently showed elevated EVLW values consistent with pulmonary edema. The results showed, however, that the Kf calculated for the dogs that received endotoxin was no different from that of control group (Kf = 0.005 ml/kg X min X mm Hg). Instead, endotoxin constricted the pulmonary veins which led to a considerable rise in microvascular hydrostatic pressure above the level at which the lungs could not resist edema formation. We conclude that acute pulmonary edema that follows endotoxin insult and subsequent therapeutic volume replacement is due to an increased filtration force instead of an alteration in the microvascular permeability.

A comparison of Escherichia coli endotoxin single bolus injection with low-dose endotoxin infusion on pulmonary and systemic vascular changes.

The purpose of this study was to compare effects of single bolus endotoxin injection with sustained low-dose endotoxin infusion on systemic and pulmonary hemodynamics in anesthetized dogs. When administered as a bolus (.01 mg/kg), endotoxin induced systemic vascular changes whose evolution could be divided into two consecutive phases. In the early phase, marked hepatic venoconstriction caused a rise in portal pressure followed by abrupt decreases in both cardiac output and blood pressure. Mean pulmonary artery pressure remained unchanged. Because of lowered blood flow, both peripheral and pulmonary resistances increased. The rise in the latter was due to a prominent vasoconstriction of pulmonary arteries. Following a partial spontaneous recovery from shock, the late phase was characterized by a low-output state combined with high systemic vascular resistances. In contrast, when endotoxin was given at a slow infusion rate (250 ng/kg/min) over a 2-hour period of time, cardiovascular effects were basically different from the preceding ones, and they were measurable only after a certain period of time had elapsed from the start of endotoxin insult. First, blood pressure decreased gradually, while cardiac output remained almost unchanged. Therefore, peripheral resistance was decreased. Second, in the pulmonary circulation, the site of vasoconstriction was shifted from arteries to veins. We conclude that there is a fundamental difference in the response of the dog's systemic and pulmonary circulation as a function of endotoxin administration as either a bolus or slow infusion. This difference might be due to sudden elevated portal pressure responsible for an abrupt cardiovascular collapse in dogs subjected to bolus injection.

Effects of Escherichia coli endotoxin on pulmonary vascular resistance in intact dogs.

The effects of endotoxin on pulmonary hemodynamics were studied in seven intact dogs. The distribution of pulmonary vascular resistance was estimated by the effective pulmonary capillary pressure, which was derived from the pressure transient recorded while the pulmonary artery catheter was rapidly wedged. After the injection of endotoxin, cardiac output and aortic pressure consistently fell. Pulmonary artery occlusion (wedge) pressure also decreased, but not significantly. Although pulmonary artery pressure did not necessarily rise, total pulmonary vascular resistance increased in every dog. The absolute increase in pulmonary artery resistance was greater (142 mm Hg/L X min/kg); than in venous resistance (111 mm Hg/L X min/kg); however, the relative increase in venous resistance was higher (410% for venous resistance vs. 220% for pulmonary artery resistance). As a result of venoconstriction, there was a consistent increase in effective pulmonary capillary pressure (from 2.5 to 6.3 mm Hg). Our data indicate that the pulmonary vascular response to endotoxin injection is characterized by constriction of both pulmonary arteries and pulmonary veins. The capillary wedge pressure did not reflect the pulmonary microvascular pressure, since it varied in the opposite direction to the effective capillary pressure.

Vestibuloocular reflex, optokinetic response, and their interactions in the alert cat.

Ocular movements of alert cats were recorded by classical electronystagmography techniques during (a) vestibular stimulation (sinusoidal rotation of the cat in complete darkness), (b) optokinetic stimulation (sinusoidal rotation of the visual surroundings around the stationary cat), (c) additive visual-vestibular stimulation (sinusoidal rotation of the cat inside the stationary lighted surroundings), and (d) conflicting visual-vestibular stimulation (sinusoidal rotation of the cat together with the visual surroundings in phase and at the same speed). The stimulus amplitudes and frequencies ranged from 3 to 20 degrees and from 0.025 to 1 Hz, respectively. When tested in darkness, the vestibuloocular reflex (VOR) gain was about 0.9 at 1 Hz. At lower frequencies, this gain was a bit lower and a phase lead was observed. The VOR system was nearly linear. The optokinetic response (OKR) gain was about 1 at lower frequencies but strongly decreased at higher frequencies. A phase lag paralleled that decrease in gain. Furthermore, the smaller the amplitude of the visual stimulus, the better the effectiveness of OKR stabilization. When working in the light, the VOR was in phase with the stimulus and its gain was nearly 1, whatever the frequency and the amplitude. The VOR inhibition was more effective at lower frequencies. In these conditions the system was markedly amplitude-dependent for both gain and phase.

Adaptive change of the vestibulo-ocular reflex in the cat: the effects of a long-term frequency-selective procedure.

Ocular movements of naive and adapted cats were recorded by classical electronystagmography techniques during: (1) sinusoidal vestibular stimulation, (2) sinusoidal optokinetic stimulation, (3) sinusoidal additive visual-vestibular stimulation, and (4) sinusoidal conflicting visual-vestibular stimulation. Adaptation of the horizontal vestibulo-ocular reflex (VOR) was produced in adult cats by sustained combined sinusoidal rotation of the cat and its surroundings (fixed-field conditions). This procedure was applied for four hours for four consecutive days. On the fifth day the VOR in darkness, the OKR, the VOR in the light and the visual suppression of the VOR were studied. VOR gain decreased from day to day and some relative frequency-specificity emerged. The gain of the visually inhibited VOR also diminished after training. This change was also frequency-specific. OKN gain, tested by a set of sinusoidal rotations, was found to be virtually unchanged. In the naive cat, VOR modified by the visual stimulus (fixed or moving) could be computed by an algebraic summation of the VOR and OKR eye movement compensations. After training, the gain of the VOR in situations where the VOR was interacting with the OKR remained easily predictable by the algebraic summation of the isolated VOR and OKR compensations.

[Progressive multifocal leukoencephalopathy after renal transplantation. Report of two cases]. / Leucoencéphalopathie multifocale progressive après transplantation rénale. A propos de deux observations.

Progressive multifocal leukoencephalopathy (PML) occurred in two patients after kidney transplantation. Two years after such a transplantation associated with immunosuppressive chemotherapy, a 54-year-old male developed polyneuropathy, diffuse alterations of the central nervous system and he died with the suspicion of hypertensive encephalopathy due to progressive renal failure. A 45-year-old female had kidney transplantation first complicated by Listeria monocytogenes meningoencephalitis. She was cured from this disease and had a satisfactory social rehabilitation for two years. Afterwards, she suffered from various neurological ailments, including epilepsy, that were attributed to combined renal failure and developing hydrocephalus. One year after the onset of these neurological symptoms, the grafted kidney was removed and chemotherapy was discontinued but she died a few weeks later. Both patients had typical PML. By electron microscopy, performed on formalin fixed brain tissue, intranuclear round particles (40-50 nm) could be recognized in the first case only. These two cases are confronted with the six published observations of PML following organ transplantation. The frequency of PML has been estimated at 1 for 5000 kidney transplantation, 1 for 2000 chronic lymphoid leukemia and 1 for 10,000 Hodgkin's disease.

Two cases of progressive multifocal leukoencephalopathy after renal transplantation.

Progressive multifocal leukoencephalopathy (PML) occurred in two patients after kidney transplantation. Less than 2 years after such a transplantation associated with immunosuppressive chemotherapy a 54-year-old male developed polyneuropathy then clinical diffuse alteration of the central nervous system. He died three months later with the suspicion of hypertensive encephalopathy due to progressive renal failure. A 45-year-old female had a kidney transplantation first rapidly complicated by Listeria monocytogenes meningoencephalitis. She was cured from this disease and had a satisfactory social rehabilitation during two years. Afterwards, she suffered various neurological troubles, including epilepsy, that were attributed to combined renal failure and developing hydrocephalus. One year after the onset of these neurological symptoms, the grafted kidney was removed and chemotherapy was discontinued. She died three months later. Both patients had typical PML with eosinophilic intranuclear inclusions in presumptive oligodendroglial cells. By electron microscopy, performed on formalin fixed brain tissue, round particles (40-50 nm) could be recognized in some glial cell nuclei. These two cases are confronted with the four published observations of PML following organ transplantation.

[Geometric representation of the human thorax in electrocardiographic theory]. / Représentation géométrique du thorax humain en théorie électrocardiographique.

An accurate representation of the thoracic surface is required to solve the inverse problem of electrocardiography. For the purpose we have searched the second degree surface which fits 55-88 positions distributed around the trunk. Over a group of 17 young men, we have found that the positions always scattered around an ellipsoid the cephalo-caudal limits of which extended far away from the zero potential gradient levels. This discrepancy is discussed and a proposal is formulated.

[Comparison between the potential maps, first measured in a Rijlant's vectocardiographic network and secondly calculated for a homogenous sphere when, in both cases, the source and the sink are opposite on the external boundary]. / Comparaison entre les nappes de potentiel d'une part mesurée dans un réseau vectocardiographique de Rijlant et, d'autre part, calculée pour une sphère homogène lorsque les poles d'alimentation sont, dans les deux cas, opposés en surface.

In order to predict quantitatively how a Rijlant's vectocardiographic network operates, we did calculate the electrical potential map generated by two opposite poles situated at the ends of a diameter in a conducting sphere isolated on its external boundary. We also measured the potentials similarly arising at each point of the network. The relation between the corresponding values may be usefully approximated. These relations are the best ones but by no means the only ones, and thus any generalization is not yet possible.

[Eccentric driving of a Rijlant's network (author's transl)]. / Effets d'une alimentation décentrée sur la répartition des potentiels dans un réseau de Rijlant.

As far as the central terminal does not interfere with the dipolar equivalent of the driving system, the zero isopotential line reaches the boundary of the network. Besides, if the emission level is at least five resistive layers "away" from the detection points, the proximity effects vanish. In these conditions the potential information available at the boundary becomes proper to be handled by the Gabor & Nelson's method. Calculating the location of the dipole leads to a fraction of the maximal "dimension" of the structure so that it directly expresses the eccentricity. The latter value may be compared with the corresponding one which is determined by the injection axis relative to the dodecahedral disposition of the connexions. From such quantitative comparisons, we conclude that an eccentricity simulating that of the heart in the thorax requires that the injection remains at least ten resistive layers "away" from the boundary if we want to view the generator through VCG leads which does not appreciably distort it.

[Attenuation and smoothness of injected signals in a Rijlant network]. / Atténuation et lissage des signaux injectés dans un réseau de Rijlant

The V.C.G. methods must handle the E.K.G. information through weighing systems, because of the volume and the eccentric location of the heart in the chest, of the inhomogeneity of the surrounding tissues and of the irregular shape of the body surface. Most of these weighing systems use compensating networks. On the other hand, Rijlant simulates an homogeneous medium where the cardiac currents spread and where remote observation would eliminate much of the distorsions. In order to understand how such a simulated medium operates, we drive it by means of sinusoidal waves and we observe how the amplitude and the phase of the signals change when we switch on the different leads. Each value recorded at a same level in the network may be considered as the sum of a true proximity effect added to an other component depending upon the lead orientation. The latter is referred to a mixed result of the driving waves that we call "the modulus effect". From the injection level to the other levels, the proximity effect rapidly vanishes while the modulus effect does not disappear until grounded level is reached. The decrease of the modulus effect either to zero (grounded level) or to a finite value (free end of the network) is not expressed as a formula because Rijlant's network does not simulate an euclidian space. We conclude that, at least as the proximity effect is concerned, the instrument performs what it is expected to do.