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Biomedical subjects

P Leissner

Publications and source records attributed to P Leissner.

44 records · Page 3Linked to original sources
PubMedDate not supplied

Effects of a behavioral intervention on epileptic seizure behavior and paroxysmal activity: a systematic replication of three cases of children with intractable epilepsy.

Three children with very frequent refractory epileptic seizures underwent a behavioral intervention consisting of symptom discrimination, countermeasures, contingent relaxation, and positive reinforcement for correct responses in a systematic replication series. The studies involved a 6-h nonintervention base rate, a 6-h treatment phase, and a 6-h nonintervention follow-up under laboratory conditions for each child. Neurophysiologic and behavioral measures of the effects of treatment were made using electroencephalogram (EEG)-video equipment. Effects of treatment were assessed by using a random sample of EEG-video sequences in base rate and follow-up. Results showed that no significant reduction of either seizure behavior or paroxysmal EEG activity was found subsequent to training in discrimination of early paroxysmal activity and/or sensations preceding seizures. Both seizure behavior and paroxysmal activity were significantly reduced in all three cases following intervention with an adapted countermeasure technique. No additional effects could be noted subsequent to the application of either contingent relaxation or positive reinforcement for correct responses. Paroxysmal EEG changes and seizure behavior were highly correlated. Reduction of the clinical manifestation or seizure response by behavioral manipulation was accompanied by a reduction of the total amount of paroxysmal activity as measured by the EEG.

Adolescent↗
PubMedDate not supplied

Evaluation of epidural sensory block by thermal stimulation, laser stimulation, and recording of somatosensory evoked potentials.

BACKGROUND AND OBJECTIVES: The existence of differential sensory block during epidural analgesia has been confirmed by some authors and disputed by others. This study attempts to elucidate this issue by using quantitative methods for evaluation of sensory block. METHODS: A single epidural injection of 20 mL 0.5% bupivacaine with epinephrine was administered at the L1-T12 level in 11 male volunteers. Sensory block was evaluated by two qualitative (pinprick and light touch) and two quantitative methods (thermal stimulation with Thermotest [Somedic, Stockholm, Sweden] and argon laser stimulation). For measurement of motor block in the lower extremities and in the rectus abdominis muscle, quantitative methods were used. Sensory block was also assessed by somatosensory evoked potentials recorded during electrical and laser stimulation at the most cranial analgesic dermatome (loss of sharpness in pinprick perception) and the anesthetic dermatome L2 (loss of light touch perception). RESULTS: The zone of anesthesia was smaller than the zone of any other investigated variable. The cranial spread of analgesia and motor block was lower than that of laser-assessed block. Partial block of laser perception and thermal perception lasted longer than analgesia and motor block. No consistent segmental or temporal differences were found between the Thermotest and laser methods. During epidural block, prolongation of latencies and reduction in amplitudes of somatosensory evoked potentials produced at the most cranial analgesic dermatome did not differ significantly from those produced at the anesthetic dermatome. CONCLUSIONS: No differential block of small nerve fibers was found during epidural analgesia by Thermotest and argon laser stimulation. Recording of somatosensory evoked potentials did not demonstrate significant difference between responses from the sites with most superficial and with most intense sensory block.

Adult↗
PubMedDate not supplied

[In vitro and in vivo inhibition of HIV1 replication by retroviral transfer of interferon alpha, beta, or gamma genes: application to gene therapy of AIDS].

Somatic gene therapy is defined as the transfer of a heterologous gene into an organism for the purpose of correcting a genetic defect or providing a new therapeutic function to the target cell and thus inducing a cure or improving associated symptoms. While encouraging results have been generated by recent clinical evaluation of combination of anti-viral drugs, Aids still constitute an obvious candidate among the infectious diseases which might be treated by gene therapy. We have therefore chosen to develop and evaluate a gene therapy strategy based on the transfer into human target cells of HIV1-inducible interferon (IFN) alpha, beta or gamma genes. In a preliminary study, myeloïd U937 cell lines transfected with expression vectors containing the IFN alpha, beta or gamma genes under the control of the long terminal repeat (LTR) sequences of HIV1 were shown to be strongly resistant against an in vitro and in vivo (in HIV1 challenged SCID mice model) HIV1 infection. This cellular resistance was correlated with a strong induction of transgenic IFN synthesis and for IFN gamma, with a defect of HIV particles maturation. Secondly, construction and production of high titer retroviral vectors containing Tat-inducible IFN genes allowed efficient transduction of lymphoïd cell lines and human primary lymphocytes. These transduced cells were shown to be highly resistant against laboratory and primary HIV isolates. Taken together, our in vitro and in vivo results suggest that HIV1 inducible IFN gene therapy can be beneficial to HIV-infected individuals provided the fact that methods are developed that allow the efficient transduction of human hematopoïetic stem cells.

Acquired Immunodeficiency Syndrome↗