Improving sample preheating capabilities for dynamic loading on high-pulsed power drivers.

The CEA operates several High-Pulsed Power (HPP) drivers for dynamic loading experiments. The aim of these experiments is to provide quantitative information about the response of various materials of interest, mainly under quasi-isentropic compression. In order to improve our ability to explore these materials' behavior over a wide range of thermodynamic paths and starting from various non-ambient conditions, we developed a device capable of pre-heating both metallic and nonmetallic samples up to several hundred degrees prior to loading. This device is based on conductive heating and on a configuration that allows homogeneous heating with unprecedented temperature stability on our HPP platforms. Moreover, it is designed to allow efficient sample heating, within extremely severe electromagnetic environments associated with such platforms. The main features of this preheating device, whose design was guided by extensive thermal simulations, are presented, along with various technical solutions that enabled its insertion in a reliable experimental configuration on our HPP drivers. The results obtained from preliminary experiments on a composite material (carbon fibers embedded in epoxy resin) and on a high purity copper sample preheated to 323 K and 573 K, respectively, are presented. The performance and robustness of this heating device are potentially valuable for extending the range of studies in dynamic loading experiments for various materials under ramp compression using HPP drivers.

Fiebre, lesiones cutáneas y pancitopenia en paciente de 88 años / Fever, maculo-papular exanthem and pancytopenia in an 88-year-old patient

Presentamos el caso de una paciente de 88 años de edad que ingresó en nuestra unidad para estudio de síndrome constitucional de unos cuatro meses de evolución, al que se añadió fiebre elevada y lesiones maculopapulosas generalizadas unos días antes del ingreso. El hemograma inicial mostró una pancitopenia. El diagnóstico sólo pudo realizarse en el estudio post mórtem, siendo éste el de síndrome linfohistiocitosis generalizada y síndrome hemofagocítico asociado a linfoma periférico de las células T (AU)

We report the case of an 88-year-old patient who was admitted in our unit for a study of an appropriate 4-month evolution of constitutional syndrome with high fever, generalized maculopapular exanthema a few days before admission. The initial blood work showed pancytopenia. The diagnosis could only be made in the autopsy study. It was hemophagocytic lymphohistiocytosis and hemophagocytic syndrome associated with peripheral T-cell lymphoma (AU)

[Haemorrhage in arteriovenous malformations of the brain following radiosurgery: the importance of the latency period]. / Hemorragia de las malformaciones arteriovenosas cerebrales tras la radiocirugía: importancia del período de latencia.

INTRODUCTION: Arteriovenous malformations are abnormal communications between arteries and veins. Treatment can consist in surgery, embolisation and/or radiosurgery. AIM: To assess the influence of radiosurgery on the risk of bleeding and related factors. PATIENTS AND METHODS: Retrospective study of 79 patients who were treated with a 6 MV linear accelerator. Clinical, morphological and dosimetric parameters were collected and a statistical analysis was performed to investigate their relationship with bleeding during the latency period. RESULTS: The mean age was 33.7 years, and 56% of patients were females. The mean volume was 6.16 cm(3). Bleeding occurred before treatment in 52.6% of cases. Altogether 25% had been embolised and 7.6% had been treated earlier using radiosurgery. Six patients suffered a haemorrhage after treatment. Bleeding occurred in 21% of those who had undergone embolisation versus 3.6% in non-embolised individuals (p < 0.02). Bleeding occurred in 33.3% of those who had been treated radiosurgically on more than one occasion, and only 5.7% if they were treated just once (p = 0.02). Bleeding took place in 28.6% of lesions above 10 cm(3) and in 3.2% when they were smaller (p < 0.01). Bleeding occurred in 16.1% of patients if they received less than 17 Gy, and in 2.22% if they received 17 or more (p < 0.01). All haemorrhages took place in treatments with more than one isocentre (p < 0.01) and with a higher homogeneity index (p < 0.01). CONCLUSIONS: Radiosurgery does not modify the risk of bleeding. The factors associated to higher percentages of bleeding are also related to poorer closure outcomes and longer latency periods.

Learned irrelevance and response perseveration in a total change dimensional shift task.

Thirty-six healthy participants received a discrimination learning task requiring the identification of a relevant stimulus dimension. After successful learning, the relevant dimension was shifted unannounced. All exemplars of the two dimensions presented after the shift were novel, implying a 'total change' design. In three experimental conditions, participants could either make only errors reflecting perseveration of responding to the former relevant dimension, continued ignoring of the former irrelevant dimension, or both. After the shift, the participants in the perseveration condition made fewer errors than did those in the other two conditions, which did not differ. These results imply a predominance of the learned irrelevance mechanism even when any direct transfer of learning about exemplars in the pre-shift phase is precluded.

Update on the Cloward procedure: new instruments.

A series of 283 patients who suffered from cervical spondylosis, herniated disc, or traumatic pathology of the cervical spine were operated on using an anterior approach. Intersomatic arthrodesis was performed in 350 cases; in every case, a threaded bone graft was screwed into the intervertebral orifice using the technique described by the author. Fusion was achieved within 6 months in 93% of cases with 92 autologous grafts and in 81% of cases with 258 heterologous grafts. In addition to the use of threaded intervertebral holes and threaded bone grafts, the Cloward technique was modified by the introduction of a set of new instruments, which largely replaced the ones previously use. These included a low-speed motor with different drills and trephines, a trephine guide retractor, and an intersomatic retractor.

Dimethyl sulfoxide inhibits human immunodeficiency virus production in vitro.

LDV/7, H9, and MOLT-4, three cell lines infectible by human immunodeficiency virus were incubated with dimethyl sulfoxide, an inducer of cell differentiation. It was shown that this is a powerful inhibitor of viral production, but its effect is transient: viral production resumes when the compound is removed from the culture medium. It does not inactivate the virus, and it fails to prevent viral infection or to inhibit expression of p24 on the surface of the infected cells.

Soluble extracts from a lymphoblastoid cell line modulate simian immunodeficiency syndrome (SAIDS) evolution.

Nineteen Macaca fascicularis monkeys were injected with SIV. They were subsequently divided into 5 groups. Four groups of 4 animals were injected with dialysable extracts (DLE) from a lymphoblastoid cell line which had been previously induced with DLE obtained either from the total lymphocyte population, or from the CD4 or CD8 subpopulations of mice immunized with SIV virus. The other three animals which constituted the control group received saline injections. The animals were kept under observation for a 108-day period, and the values of several biological parameters were compared in a multivariant statistical analysis. On the 108th day, the control group was significantly different from the other groups in the multivariant analysis. Furthermore, the CD4/CD8 ratio and the platelets and CD4 cell counts varied significantly between the groups in the univariant analysis. It is thus surmised that DLE obtained from CD8 cells or the total lymphocyte population of immunized animals may exert a modulating effect on the evolution of SAIDS.

[The regulatory role of silicon in cell division]. / Le rôle régulateur du silicium dans la division cellulaire.

Several reports have suggested that silicon has an activating effect on cell proliferation. In order to test this hypothesis, both peripheral human lymphocytes and LDV/7 lymphoblast cells were cultured in the presence of a compound composed of monomethylsilanetriol (silanol), a soluble organic form of silicon, and serine. This molecule stimulates peripheral lymphocyte proliferation at an optimal concentration of 10 mg of silicon per liter of culture medium; in identical conditions, it inhibits the growth of lymphoblastoïd cells (p less than 0.001). Silanol-serine also inhibits the growth of PHA stimulated lymphocytes. The effect of silicon on cell growth has a negative correlation (p less than 0.001) with the mitotic activity of cultured cells: the more intense the latter, the stronger is the inhibitory effect of silanol-serine. This would suggest a regulatory role of this compound on the cell cycle.

Specific transfer factor protects mice against lethal challenge with herpes simplex virus.

Bovine transfer factor (TFd) specific to herpes simplex virus (HSV)1 or to HSV2 was prepared by immunizing calves with the corresponding virus. The TFd preparations were then injected into Swiss mice in an attempt to protect them against a subsequent lethal challenge with HSV1 or HSV2 virus. It was thus shown that injection of anti-HSV TFd protects the mice against the corresponding HSV virus, whereas the injection of a nonspecific TFd (anti-CMV) fails to protect against a challenge with HSV1. Furthermore, a dose-response effect was observed, since potent TFd preparations were ineffective when they were used at one-fifth of the original concentration. It seems, therefore, that animal models may be used to assay the potency of TFd preparations specific for herpes viruses.

Anterior cervical interbody fusion with threaded cylindrical bone.

The author describes some modifications of the original Cloward method of cervical intervertebral body fusion. These modifications include the intraoperative threading of the standard cylindrical graft dowel (either autologous or heterologous) and the development of two new instruments designed to insert the graft into the intervertebral space. This modified technique was tested in an experimental study using the cervical spine of cadavers, after which a series of 37 patients were operated on with this method. The results of both series are presented. The chief advantages of this type of interbody fusion over the standard technique are: 1) easier insertion of the graft into the intervertebral space; and 2) decrease in complications. Complications with cervical interbody fusion, both minor (such as partial displacement of the graft, vertebral angulation, and radicular injury) and major (such as spinal cord compression and/or contusion), are fortunately infrequent, but they are important because of their irreparable consequences.

[Treatment of herpes infections with transfer factor]. / Traitement des infections herpétiques par le facteur de transfert.

Twelve patients suffering from recurrent herpetic infections resistant to several current therapies were treated for a 3 to 10 months period with a bovine transfer factor specific to Herpes simplex virus of type 1 and 2. The results obtained showed that this treatment was capable of dramatically reducing the intensity, duration and frequency of the relapses. This preliminary clinical trial suggests that specific transfer factor administered orally could be an effective treatment of herpes infections.