[Exploration of traumatic brain-injury attention difficulty by event-related potentials]. / Exploration des troubles attentionnels des traumatisés crâniens avec les potentiels évoqués cognitifs.

OBJECTIVE: To specify, in cognitive processing leading to an action, the localization of difficulties in attention following severe, traumatic brain injury. METHOD: Stimulus-locked and response-locked event-related potentials were recorded during a Stroop task in 25 patients with traumatic brain injury and 25 control subjects approximately 4 months after the accident. The latency and amplitude of the waves were compared between the two groups and correlated with clinical data. RESULTS: The reaction times of brain-injured patients were significantly longer than those of the control group, but neither the number of errors nor the interference differed between the groups. Electrophysiological recordings showed early abnormalities between 100 and 200 ms after stimulus onset. The key area could be the medial occipitotemporal side connected with frontal regions. Recordings also showed disruptions in motor program monitoring, which implied frontomedial areas. CONCLUSION: This protocol allows for precisely dating cognitive abnormalities. Future studies should relate cognitive with neuropsychological abnormalities and examine the possibilities of later regression.

Effects of 8 days acclimation on biological and performance response in a tropical climate.

BACKGROUND: This study was designed to determine the acclimation process elicited by exposure to a tropical climate. METHODS: Nine triathletes performed 3 outdoor indirect continuous running multistage tests in both thermoneutral and tropical conditions. Before travelling to the tropical area (Martinique Island, FWI), the triathletes performed the thermoneutral test (TN) in 14 degrees C and 45% rh conditions. The tropical tests were performed 2 and 8 days after arrival (T2 and T8, performed at a mean environmental temperature of 33.4 degrees C and 75.5% rh). The day before T8, blood samples were drawn for biochemical analysis. During each test, tympanic temperature, sweat rate, weight loss, heart rate (HR), and performance were recorded. RESULTS: The results demonstrated that: 1) the mean tympanic temperature was greater in T2 (p<0.001) and T8 (p<0.01) than in TN; 2) the mean sweat rate was significantly greater (p<0.001) in T2 and T8 than in TN and significantly greater in T8 than in T2 (p<0.03); 3) the weight loss after trials was significantly greater (p<0.001) in T2 and T8 than in TN and in T8 than in T2 (p<0.04); 4) the mean HR and the HR at rest were significantly greater in T2 than in TN (p<0.001) and T8 (p<0.005); 6) significant reductions were observed in T8 vs TN in red cell count (p<0.05) and plasma proteins (p<0.04), the consequence of a 7.5% plasma volume expansion; and 7) the performance was significantly lower in both T2 (p<0.02) and T8 (p<0.03) than in TN. CONCLUSIONS: We concluded that 8 days exposure to hot/wet conditions induced impairments in physiological responses and performance that were still evident on the 8th day. Further and longer outdoor studies are needed to investigate if return to optimal performance levels after adaptation to hot/wet conditions is possible.

[Auditive and somato-sensory event-related potentials in comas: prognostic value for awakening, social and professional reinstatement]. / Les potentiels évoqués cognitifs, auditifs et somesthésiques dans les comas: valeur pronostique pour l'éveil et la réintégration socioprofessionnelle.

OBJECTIVE: To appreciate prognostical value of event-related potentials in comatose states and the influence of the stimulation's modality. PATIENTS AND METHODS: Thirty-five patients were recorded with the auditory modality whose thirteen were also recorded with the somesthetic modality. They were free of sedation except for five. For 21 patients out of coma, it was possible to get information about their social readaptation 14 months later. RESULTS: When present, cognitive components predict awakening in 100 % of the cases, but only 50 % of the patients who awake had these components. The somesthetic modality seemed to enlarge their detection, but did not improve short-term forecasts. We could not confirm their absence could hamper social reinstatement. CONCLUSION: Event-related potentials are strengthened as having excellent positive prognostic value. Further studies should clarify the interest of the somesthetic modality, and the possibility to get remote prognostic.

Residual human immunodeficiency virus type 1 RNA in lymphoid tissue of patients with sustained plasma RNA of <200 copies/mL.

Human immunodeficiency virus type 1 (HIV-1) RNA was measured in lymph node (LN) mononuclear cells of 50 patients with sustained plasma RNA of <200 copies/mL with therapy. Six patients had received a combination of three reverse transcriptase inhibitors (RTIs) since primary infection, 11 received this same combination during chronic disease, 21 received a combination of two RTIs plus a protease inhibitor (PI), and 12 received three RTIs plus a PI. The mean overall duration of therapy was 8.9 +/- 0.5 months (range, 5-24), with no significant difference between groups. LN HIV-1 RNA levels varied from undetectable to 1.7 million copies/10(6) cells according to cases. The mean LN HIV-1 RNA level was 2.99 +/- 0.42 log10 copies/10(6) cells in the 17 patients receiving three RTIs compared with 1.93 +/- 0.25 log10 copies/10(6) cells in the 33 patients receiving a PI (t test, P = .02). These data demonstrate that highly active antiretroviral regimens have unequivalent effects on LNs and invite redefinition of suboptimal therapy at this level.

Effects of a combination of zidovudine, didanosine, and lamivudine on primary human immunodeficiency virus type 1 infection.

A combination of zidovudine, didanosine, and lamivudine was used to treat 10 patients with primary human immunodeficiency virus type 1 (HIV-1) infection 5-28 days after the onset of symptoms. When therapy began, the mean plasma HIV-1 RNA level was 5.31 +/- 0.33 log10 copies/mL and the mean CD4 T cell count was 630 +/- 112 x 10(6)/L. The plasma HIV-1 RNA level decreased rapidly, and levels dropped below the cutoff in each case after 108 +/- 32 days. Lymph nodes from 5 patients were biopsied before therapy and during follow-up. Infectious HIV-1 could not be cultivated from any lymph node mononuclear cells taken on day 90, and HIV-1 RNA was at very low levels in lymph nodes after 1 year. In some cases, waning of the antibody response to HIV-1 was shown by Western blot after several months of undetectable plasma RNA. These data demonstrate that triple-drug therapy has a potent antiviral effect during primary HIV-1 infection.

Human immunodeficiency virus type 1 kinetics in lymph nodes compared with plasma.

As lymphoid organs are the major reservoir of human immunodeficiency virus type 1 (HIV-1), the rates at which HIV-1 RNA decreases from the plasma and from a series of lymph node biopsies from 4 patients treated with a combination of zidovudine, didanosine, and lamivudine were measured. The concentrations of HIV-1 RNA in the plasma and in lymph nodes declined exponentially, with mean half-lives of 1.88 +/- 0.86 days for plasma and 6.01 +/- 3.44 days for lymph nodes. These data show that most of the HIV-1 in lymphoid organs is due to the infection of new cells and demonstrate that a triple-drug combination is able to target this compartment.

[Animal modeling and experimental pharmacology of human spasticity]. / Modélisation animale et pharmacologie expérimentale de la spasticité humaine.

The first part of the paper exposes the basic characteristics of the human spasticity which should be modeled: No hypertonia at rest; velocity-dependent myotatic responses, and fatigability. To model a syndrome including these signs is a related but different problem. Results and limits of the clinical neurophysiology concerning the spasticity are briefly quoted. Animal models would better assist the human neurophysiology when having their neuroanatomy closer to the human one. The second part confirms that a local unilateral excision of the ad hoc sensorimotor cerebral cortice of the Baboon induces a permanent palsy of the contralateral foot and leg, and after delay signs of spasticity in the Sol. Neither clasp-knife phenomenon nor fatigability is observed. There is no sign of motoneuron hyper-excitability. A GABA-related pharmacology suggests a significant defect in the presynaptic inhibition of the reflexogenic IA in-put, and possibly a defect in a post-synaptique gabaergic inhibition. Finally the monkey is considered as a valuable support for modeling the human spasticity, symptom and possibly syndrome.