An inferior vena cava discontinuity with an hepato-renal accessory vein development: A radio-anatomical morphometric case study.

PURPOSE: Inferior vena cava (IVC) agenesis is an uncommon congenital vascular anomaly stemming from aberrant development during embryogenesis. It results from the failure of one or more of the supracardinal veins, subcardinal veins, vitelline veins or postcardinal veins to connect. The symptomatology resulting from this vascular malformation can be either absent or extremely rich and varied. METHODS: Thoracoabdominal-pelvic CT scan projections following iodine-based contrast product injection were analyzed and a three-dimensional model of vascularization constructed. RESULTS: Herein, an asymptomatic case of IVC agenesis with absence of the suprarenal and renal segments, with azygos continuation, presenting an accessory hepatorenal vein is reported. The presence of this type of accessory vein has never been described in the literature to date. The etiology of this case of IVC agenesis is explored in depth. We also analyzed the morphometric parameters of the IVC remnant segments and the azygos vein in order to quantify the dilatation of the collateral venous pathway overdeveloped to handle blood return. CONCLUSION: Using the findings from this case and those reported in the literature, we provide general recommendations that should be taken into account before managing a patient, symptomatic or asymptomatic, admitted to the hospital with IVC agenesis.

Effects of diclofenac on sentinel species and aquatic communities in semi-natural conditions.

Due to the potential hazard of diclofenac on aquatic organisms and the lack of higher-tier ecotoxicological studies, a long-term freshwater mesocosm experiment was set up to study the effects of this substance on primary producers and consumers at environmentally realistic nominal concentrations 0.1, 1 and 10 µg/L (average effective concentrations 0.041, 0.44 and 3.82 µg/L). During the six-month exposure period, the biovolume of two macrophyte species (Nasturtium officinale and Callitriche platycarpa) significantly decreased at the highest treatment level. Subsequently, a decrease in dissolved oxygen levels was observed. High mortality rates, effects on immunity, and high genotoxicity were found for encaged zebra mussels (Dreissena polymorpha) in all treatments. In the highest treatment level, one month after the beginning of the exposure, mortality of adult fish (Gasterosteus aculeatus) caused effects on the final population structure. Total abundance of fish and the percentage of juveniles decreased whereas the percentage of adults increased. This led to an overall shift in the length frequency distribution of the F1 generation compared to the control. Consequently, indirect effects on the community structure of zooplankton and macroinvertebrates were observed in the highest treatment level. The No Observed Effect Concentration (NOEC) value at the individual level was < 0.1 µg/L and 1 µg/L at the population and community levels. Our study showed that in more natural conditions, diclofenac could cause more severe effects compared to those observed in laboratory conditions. The use of our results for regulatory matters is also discussed.

Cortical mechanisms underlying stretch reflex adaptation to intention: a combined EEG-TMS study.

During voluntary motor acts, potential perturbations due to transient external forces are counteracted very quickly by short- and long-latency stretch reflexes (SLSR and LLSR, respectively). The LLSR, presumably linked to a transcortical loop, can be modulated by the subjects' intention. Here, we used combined TMS-EEG to study cortical mechanisms involved in this intention-related modulation both before and during the reaction to a mechanical perturbation. Subjects had to prepare for a brisk wrist extension under the instruction either to 'resist' the perturbation or to 'let-go'. Following the perturbation, the early cortical evoked activity (45-75 ms) was greater in the 'let-go' condition; moreover, its amplitude was negatively correlated with the LLSR amplitude, regardless of condition. After 100 ms the pattern reversed, the late evoked activity (presumably linked to the voluntary reaction) was greater in the 'resist' condition. The early and late evoked activities also differed in their topography. Therefore, the cortical mechanisms involved in the intention-related LLSR modulation differ from those involved in the voluntary reaction. In addition, in response to a single-pulse TMS delivered during the expectation of the mechanical perturbation, the TMS-evoked N100 amplitude decreased when subjects intended to 'let-go', suggesting anticipatory decreased activity of intracortical inhibitory sensorimotor networks. Taken together, these results support the idea that anticipatory processes preset the sensorimotor cortex so as to adapt its early reaction to the perturbation relative to the subjects' intention.

Protein kinase B regulates T lymphocyte survival, nuclear factor kappaB activation, and Bcl-X(L) levels in vivo.

The serine/threonine kinase protein kinase B (PKB)/Akt mediates cell survival in a variety of systems. We have generated transgenic mice expressing a constitutively active form of PKB (gag-PKB) to examine the effects of PKB activity on T lymphocyte survival. Thymocytes and mature T cells overexpressing gag-PKB displayed increased active PKB, enhanced viability in culture, and resistance to a variety of apoptotic stimuli. PKB activity prolonged the survival of CD4(+)CD8(+) double positive (DP) thymocytes in fetal thymic organ culture, but was unable to prevent antigen-induced clonal deletion of thymocytes expressing the major histocompatibility complex class I-restricted P14 T cell receptor (TCR). In mature T lymphocytes, PKB can be activated in response to TCR stimulation, and peptide-antigen-specific proliferation is enhanced in T cells expressing the gag-PKB transgene. Both thymocytes and T cells overexpressing gag-PKB displayed elevated levels of the antiapoptotic molecule Bcl-X(L). In addition, the activation of peripheral T cells led to enhanced nuclear factor (NF)-kappaB activation via accelerated degradation of the NF-kappaB inhibitory protein IkappaBalpha. Our data highlight a physiological role for PKB in promoting survival of DP thymocytes and mature T cells, and provide evidence for the direct association of three major survival molecules (PKB, Bcl-X(L), and NF-kappaB) in vivo in T lymphocytes.

The influence of thermal desorption on genotoxicity of multipolluted soil.

A multipolluted soil sampled from a former coking plant in Lorraine (France) was evaluated for its genotoxic effects on coelomocytes of the Eisenia fetida earthworm using the comet assay. The biological efficiency of thermal desorption of the contaminated soil was also investigated. The untreated polluted soil was shown to be genotoxic to earthworms. Although thermal desorption reduced the concentration of PAHs by 94% (Sigma(16 PAHs)=1846 and 101 mg/kg before and after thermal desorption, respectively), the treatment did not eliminate the genotoxicity of soil pollutants to earthworms but increased it. The concentration of non-volatile metals did not change after thermal desorption. Among metals found in the treated soil, cadmium, chromium and nickel could explain the genotoxicity of the contaminated soil after thermal desorption. The treatment could increase the bioavailability and genotoxicity of heavy metals, through a modification of the soil's organic matter, the speciation of heavy metals and their binding to organic matter. This study underlines the importance of measuring biological effects, in order to evaluate the risk associated with formerly contaminated soils and the efficiency of remediation.

Prior intention can locally tune inhibitory processes in the primary motor cortex: direct evidence from combined TMS-EEG.

Human subjects are able to prepare cognitively to resist an involuntary movement evoked by a suprathreshold transcranial magnetic stimulation (TMS) applied over the primary motor cortex (M1) by anticipatory selective modulation of corticospinal excitability. Uncovering how the sensorimotor cortical network is involved in this process could reveal directly how a prior intention can tune the intrinsic dynamics of M1 before any peripheral intervention. Here, we used combined TMS-EEG to study the cortical integrative processes that are engaged both in the preparation to react to TMS (Resist vs. Assist) and in the subsequent response to it. During the preparatory period, the contingent negative variation (CNV) amplitude was found to be smaller over central electrodes (FC1, C1, Cz) when preparing to resist compared with preparing to assist the evoked movement whereas alpha-oscillation power was similar in the two conditions. Following TMS, the amplitude of the TMS evoked-N100 component was higher in the Resist than in the Assist condition for some central electrodes (FCz, C1, Cz, CP1, CP3). Moreover, for six out of eight subjects, a single-trial-based analysis revealed a negative correlation between CNV amplitude and N100 amplitude. In conclusion, prior intention can tune the excitability of M1. When subjects prepare to resist a TMS-evoked movement, the anticipatory processes cause a decreased cortical excitability by locally increasing the inhibitory processes.

Bioavailability of chemical pollutants in contaminated soils and pitfalls of chemical analyses in hazard assessment.

Decision-making for remediation of industrial wastelands are still based on the concentrations of pollutants of concern measured in soils. In this work, two soils polluted by polycyclic aromatic hydrocarbons (PAHs) and metals were investigated for their toxicity on earthworms (Eisenia fetida), collembolae (Folsomia candida), and higher plants (Brassica chinensis, Lactucca sativa and Avena sativa) in order to study the relationships between chemical contamination and biological effects. Although the level of contamination by PAHs was elevated and commensurate in the two soils, their toxicity profile was quite different. Soil A affected survival and reproduction of invertebrates and growth of higher plants. Surprisingly, soil B, heavily contaminated by metals in addition to PAHs, was devoid of toxicity. Our results indicate that toxicity cannot simply be extrapolated from pollutant concentrations in a complex matrix in which bioavailability of pollutants may be reduced by ageing. Moreover, the use of toxicity data obtained from spiked soils characterized by readily bioavailable pollutants can also be called into question for such extrapolations. Predicting biological effects therefore requires biological tools to avoid any erroneous conclusions that can be drawn from sole extrapolation of analytical results.

Steady-state fluctuations of human walking.

In steady-state walking, fluctuations in space-time behavior are observed for normal adult subjects. In the present study, the intrinsic fluctuations of gait have been analyzed when walking on a subject-driven treadmill (with adjustable inertial forces). Furthermore, these intrinsic fluctuations have been compared with those observed in natural overground locomotion which involves a real subject's displacement and thus an optical flow. Four adult subjects participated in both experimental sessions. It was found that the frequency and amplitude of the instantaneous fluctuations of leg movement were weak and of equal magnitude with or without optical flow. This was also the case for instantaneous fluctuations in displacement speed. Secondly, a low-frequency fluctuation in walking speed was observed when no optical flow information was available to the subject. This fluctuation results from the addition of a series of leg-movement fluctuations, whose values are all either positive or negative. As the optical flow provides information about the displacement speed, it allows the subject to avoid such addition, and thus plays a role in maintaining steady leg movement. Theoretical models linking space-time behavior of rhythmic movement with stiffness strongly suggest that the observed low-frequency fluctuations in speed result from fluctuations in stiffness.

Joint-dependent mechanisms to adapt to an imbalance between flexion and extension forces in human gait.

In human gait, alternating leg flexion/extension movements essentially require the production of extension muscle forces due to the large contribution of passive forces to leg flexion. In this experiment, we studied the adaptive capabilities of walking subjects constrained with elastic cords which further facilitated leg flexion and impeded leg extension. In order to walk, the subjects let the moments created by the elastic cords increase the ankle flexion during the whole cycle, which allowed them to reduce part of these moments. By contrast, at the knee level, they increased their extension muscle activity to compensate for the remaining constraint moments during the swing phase, which resulted in unchanged kinematics. Although neuromuscular locomotor synergy is often considered to control the lower limb as a unit, we showed here that different adaptive mechanisms can act at different joints of the same leg.

Different strategies to compensate for the effects of fatigue revealed by neuromuscular adaptation processes in humans.

An initially submaximal hopping task was maintained with the same global power output until it became the maximal performance; since there was no decrease in performance, any change in behavior occurring with fatigue characterizes the strategies allowing to compensate for the effects of fatigue. In a prolonged hopping task, fatigue is likely to be most prominent in the ankle extensor muscles since they are the main contributors to vertical propulsion in the hop. With fatigue, all subjects landed with more flexed knees and with an increased activity in the biarticular rectus femoris muscle indicating some compensation between the knee and ankle joint. Furthermore, two different strategies appeared to further compensate for the important fatigue of the ankle extensor muscles: one was organized across joints and consisted in a heavier reliance of the knee extensor vastus lateralis, and the other was organized within the fatigued joint and consisted in an earlier preactivation of the gastrocnemius. As a consequence, two different adaptations of the ground reaction force profiles appeared at the end of the session; each being related to one of these two strategies.

Intentionality in human gait control: modifying the frequency-to-amplitude relationship.

Tight frequency-to-amplitude relationships are observed in spontaneous human steady gait. If required, however, they can be modified. The following experiments were aimed at the processes underlying this flexibility, which forms the fundamental basis of the intentional adaptive capabilities of locomotion. In Experiment 1, Ss had to intentionally modify the frequency-to-amplitude relationship (leading to preferred or nonpreferred steady states). In Experiment 2, they had to temporarily perturbate the stride-frequency-to-amplitude relationship to intentionally shorten or lengthen 1 stride. Within the important constraints exerted by the head-arm-trunk system on leg movement, the results pointed out 2 main strategies that allow the S to intentionally adapt stride organization on-line: adjustment of the tonic properties of the oscillating leg to achieve nonpreferred steady states and phasic action to ensure temporary movement away from a steady state.

Serial transplantation and characterization of a canine diffuse large cell lymphoma grafted in nude mice.

A continuous canine lymphoma cell line (DL. 24N) was established by serial transplantation from a diffuse large cell lymphoma into athymic nude mice, yielding subcutaneous tumours at the injection site associated with lymph node metastasis. The transplanted tumour cells, of canine origin as assessed by the karyotype, appear comparable to the large non-cleaved and immunoblastic human cells, as did the initial tumour cells. Immunological studies show reactivity with antibodies to dog immunoglobulins, DT-2 and Thy-1, to MHC-class II antigens, and to both CD10 (CALLA) and CD21 (CR2) human antigens. Such a cell line, showing similarities with some of the human diffuse large cell lymphomas, will thus provide a new tool for further comparative studies of malignant lymphomas.

Stride variability in human gait: the effect of stride frequency and stride length.

This study focused on spatial and temporal variability of the stride in human gait. We determined the role of stride frequency (F) and stride length (L) on those parameters. Eight healthy subjects walked on a treadmill using 25 different FL combinations (0.95

Intentional compensation for selective loading affecting human gait phases.

The locomotor strategies used by 12 subjects, instructed to hold their walking speed constant, were examined under various dynamic conditions in order to determine the means by which subjects can act upon their basic locomotor synergy. The dynamic conditions were modified either by adding a load or applying an impeding force. These modifications were designed to selectively affect either the stance phase or the swing phase. The results show that (a) subjects were able to rapidly calibrate their efforts to hold their walking speed constant, (b) in all conditions, the same walking speed was achieved with the same stride lengths and durations, and (c) at the within-cycle level, a change in duration synergically affected both phases and not just the perturbed one. The above results are discussed in terms of intentionally controlled parameters. Because cadence is closely linked to walking speed, it can be used as feedback; the control of walking speed in our experiments may thus be achieved simply by increasing the exerted force until the same cadence is produced.

Adaptation of neuromuscular synergies during intentional constraints of space-time relationships in human gait.

Tight frequency-to-amplitude relationships are observed in spontaneous human steady gait. They can be modified, if required; that flexibility forms a fundamental basis of the intentional adaptive capabilities of locomotion. In the present experiments, the processes underlying that flexibility were investigated at both the level of joint kinematics and the level of neuromuscular synergies. Subjects (N = 4) walked at the same speed either with a preferred or a nonpreferred frequency-to-amplitude relationship (i.e., constrained, short steps at a high frequency [COS condition] or constrained, long steps at a low frequency [COL condition]); their swing and stance phases were separately analyzed. In the COS condition, increases in EMG activity were specifically required during the swing phase. In the COL condition, several muscles required increases in EMG activity during the stance phase, but decreases of the hamstring muscles were needed during the swing phase. Whereas, in preferred walking, modification of the frequency affects the EMG patterns globally (the gain increasing with the frequency in both the stance and swing phases), the present results show that changing the frequency in a constrained manner either affects the swing phase specifically or affects both phases, but in the opposite direction. That finding indicates that a separate control is needed in both the swing and the stance phases.

[Study of the immune profile of pregnant women]. / Etude du profil immunitaire de la femme enceinte.

During pregnancy, the fetus is an hemiallograft perfectly tolerated by the mother. With the aim of elucidating the mechanism of this tolerance, we have looked to see whether lymphocyte subsets are modified by pregnancy. Using monoclonal antibodies and flow cytometry, we have studied the changes in the immune profile of normal pregnant women and compared them with non pregnant women. In pregnant women, a significant decrease in the percentage of CD3+ cells is observed in the first trimester (61.1 +/- 14.7% versus 73.8 +/- 6.8%; p less than 0.001). The same data are obtained for CD4+ cells (38.2 +/- 10.7% versus 44.0 +/- 7.0%; p less than 0.05) and CD8+ cells (22.8 +/- 5.6% versus 28.0 +/- 8.9%; p less than 0.05). On the other hand, B lymphocytes (CD19+), monocytes (Leu M3+) and natural killer (NK) cells (Leu7+) remain stable during pregnancy. CD11a+ cells decreased during the 1st and 2nd trimesters. Lastly, activated T lymphocytes (CD3+DR+, CD8+DR+) are not modified. Using absolute numbers, a significant decrease is shown only for CD3+ cells in the 2nd and 3rd trimesters and for CD11a+ cells in the 2nd trimester of pregnancy. The decrease of T lymphocyte subsets, NK and CD11a+ cells during pregnancy partially explains the tolerance for the fetus.

[Comparative hemodynamic effects of midazolam and flunitrazepam in head injury patients under controlled ventilation]. / Effets hémodynamiques comparés du midazolam et du flunitrazépam chez les traumatisés crâniens en ventilation contrôlée.

The haemodynamic effects of midazolam were compared with those of flunitrazepam in 10 patients with severe head injury under controlled ventilation. Right atrial pressure, pulmonary pressure, pulmonary capillary wedge pressure and cardiac output were measured using a Swan-Ganz thermodilution catheter. Arterial pressure (Pa) was recorded by radial arterial canulation. All patients in this cross-over study received midazolam (0.15 mg X kg-1) and flunitrazepam (0.02 mg X kg-1) intravenously randomly, with 24 h between the two injections. The measurements were first carried out before and then 5, 10, 20, 30 and 60 min after injection. The only significant variations after midazolam and flunitrazepam were a fall in Pa (from 93 +/- 12 to 81 +/- 11 mmHg for midazolam and from 89 +/- 14 to 78 +/- 20 mmHg for flunitrazepam) and in cardiac index (from 4.80 +/- 1.03 to 4.17 +/- 1.14 l X min-1 X m-2 for midazolam and from 5.18 +/- 1.32 to 4.54 +/- 1.03 l X min-1 X m-2 for flunitrazepam). The small decrease in heart rate was not significant. The cardiovascular changes after midazolam and flunitrazepam were small and similar for both drugs. It seemed that midazolam and flunitrazepam were safe for sedating head injured patients under controlled ventilation.

[Prevention of late post-traumatic epilepsy by phenytoin in severe brain injuries. 2 years' follow-up]. / Prévention de l'épilepsie post-traumatique tardive par phénytoïne dans les traumatismes crâniens graves. Suivi durant 2 ans.

The high incidence rate and the invalidating nature of post-traumatic epilepsy after severe brain injury have encouraged the authors to review the prophylactic treatment of this type of epilepsy. Thirty-four out of 86 randomised patients with brain injuries admitted into a neurotraumatology intensive care unit were treated prophylactically, immediately after the injury, with an intravenous hydantoin injection in a dose sufficient to provide stable and effective blood levels. This was followed by dose-adjusted oral administration maintained for a minimum period of 3 months. After a 2 years' follow-up, there was a significant difference between treated and untreated patients, since only 6 per cent of the patients treated suffered from post-traumatic epilepsy, as against 42 percent in the untreated group.

[Diagnostic and therapeutic problems of osteomeningeal defects and traumatic cerebrospinal fluid defects of the anterior floor of the base of the skull. Apropos of 95 cases]. / Problèmes diagnostiques et thérapeutiques des brèches ostéoméningées et des fistules liquidiennes traumatiques de l'étage antérieur de la base du crâne. A propos de 95 cas.

The authors here report teaching drawn from the latest ninety five cases of osteo-dural defects in basilar skull fractures they have surgically treated. They particularly insist on the following points: Difficulties in establishing a clinical diagnosis when the traumatism is in its acute stage: initially 55% of patients do not show any symptom of rhinorrhea, so that the diagnosis is only based on X-ray data. Previous to any surgical treatment the number of serious septic meningitis is rather high in as much as it reaches 10.55% in this series. Risk of infection together with bone damages incite the authors to suggest a surgical treatment of dural defects in their acute stage, namely within the two weeks following the accident. The study of results shows that due to treatment complications, are not insignificant. The authors then tackle the problems of technics and osteo-dural restoration. They, at last, explain, in this series, the interest of preventive antiepileptic treatment by hydantoins during and after the operation. Despite complications due to treatment the results in this series appear to be significant enough to allow the authors to place the indication of the surgical treatment of traumatic osteo-dural defects in basilar skull at the acute stage of their evolution.

[Early per- and postoperative epileptic seizures during operations on osteomeningeal breaches. Value of preventive treatment with hydantoins]. / Crises épileptiques per-opératoires et post-opératoires précoces lors d'interventions sur brèches ostéo-méningées. Intérêt du traitement préventif par les hydantoines.

The value of prophylactic anti-epileptic treatment in surgery of osteomeningeal breaches has been studied. This surgery exposes to a high risk of seizures, 20 to 25 of our cases after conventional surgery. 74 operated cases of osteomeningeal breaches, among then 38 under preventive anti-epileptic therapy are reviewed. The pre and postoperative epileptic fits up to 24 hours after the operation were taken in consideration.