Short-interval amygdala kindling in neonatal rats

The kindling paradigm provides a powerful tool for studying the generation, propagation and generalization of seizures. Such reproducible quantitative paradigms are a prerequisite for the experimental study of epilepsy in the developing brain. Kindling has been extensively utilized as a model of limbic seizures in the adult rat; amygdala short-interval kindling has been studied in > or = 15-day-old rats. We applied the short-interval kindling method, i.e., stimulation at every 15 min, to 7-12-day-old rats. Stage-5 behavioral seizures were achieved even in 7-day-old rats; however, the progression of behavioral kindling differed somewhat from that of older rats. Correlation of electrographic discharges and behavioral phenomena was inversely related to age. Reliable progressive amygdala discharges were difficult to assess in most < or = 10-day-old rats. Spontaneous seizures occurred relatively frequently in younger age groups. The amygdala short-interval kindling paradigm is reproducibly and reliably applicable to rats during the 2nd postnatal week. The presence of progressive focal to bilateral-generalized seizures suggests a significant functional maturity of the amygdala-limbic circuitry at this age.

Expression of beta 1 integrin complexes on the surface of unfertilized mouse oocyte

Integrins are a family of cell surface receptors that mediate cell-cell and cell-matrix interactions in a variety of different cellular systems. Here we show that unfertilized mouse oocytes express beta 1 class integrins both at mRNA and protein levels. Using the reverse transcription polymerase chain reaction and oligonucleotide primers based on the DNA sequence of mouse integrins, the RNA transcripts for the beta 1, alpha 5 and alpha 6 subunits were detected in unfertilized oocytes. The expression of the mRNAs is paralleled by the expression of the corresponding proteins, in fact, the alpha 5/beta 1 and the alpha 6/beta 1 complexes can be immunoprecipitated with specific antibodies form 125I-surface-labeled oocytes. Using subunit-specific antibodies we also demonstrate the presence of the alpha 3/beta 1 at the oocyte surface but alpha 1, alpha 2, alpha 4 or alpha V subunits were not detectable. Since the mouse alpha 3 DNA sequence is not available, we have not tested for the corresponding transcript. Integrin subunits alpha 6 and beta 1 were differently distributed on the oocyte surface, as visualized by immunofluorescence staining and by immunoelectron microscopy. alpha 6 antigen was mainly confined to the microvillous area of the oocyte surface, while beta 1 was more homogeneously distributed over the whole oolemma. These data demonstrate for the first time the expression of three beta 1 integrin complexes in unfertilized mouse oocytes. Such proteins may have a role in sperm-egg interaction or during very early steps of embryogenesis.

Ontogenic study of lithium-pilocarpine-induced status epilepticus in rats

Lithium is known to potentiate the ability of pilocarpine to induce status epilepticus in rats. The goal of this study was to determine whether lithium could potentiate pilocarpine-induced seizures in developing animals. Behavioral, electroencephalographic (EEG), and histopathological changes induced by systemic administration of lithium (3 meq/kg) followed 20 h later by pilocarpine (3, 10, 30, 60 mg/kg) were studied in 3-30-day-old rats. Lithium followed by pilocarpine (30 and 60 mg/kg) induced hyperactivity, tremor, loss of postural control and scratching but no electrographic seizures in 3-8-day-old rats. In the 7-10-day-old animals pretreatment with lithium and pilocarpine 60 mg/kg induced status epilepticus with sustained myoclonus and continuous bilateral synchronous spike and sharp wave, but doses of pilocarpine lower than 60 mg/kg had no effect. The susceptibility to lithium-pilocarpine-induced status epilepticus increased markedly during the third postnatal week of life. During this time period, rats treated with lithium (3 meq/kg) plus pilocarpine 10 mg/kg exhibited behavioral and EEG manifestations of status epilepticus. The same combination of lithium and pilocarpine failed to induce status epilepticus either before or after the third week of life. Histopathological analysis of the brains of the animals used in these studies failed to demonstrate the widespread damage reported in adult rats that have undergone lithium-pilocarpine-induced status epilepticus.

Age-related differences in recovery from simulated jet lag

Six healthy young men and eight early middle-aged men were isolated from environmental time cues for 15 days. For the first 6-7 days (one or two nights adaptation, four nights baseline), their sleep and meals were scheduled to approximate their habitual patterns. Their daily routines were then shifted 6 hours earlier by terminating the sixth or seventh sleep episode 6 hours early. The new schedules were followed for the next 8 or 9 days. Important age-related differences in adjustment to this single 6-hour schedule shift were found. For the first 4-day interval after the shift, middle-aged subjects had larger increases of waking time during the sleep period and earlier termination of sleep than young subjects. They also reported larger decreases in alertness and well-being and larger increases in sleepiness, weariness and effort required to perform daily functions. The rate of adjustment of the circadian core temperature rhythm to the new schedule did not differ between groups. These results suggest that the symptoms reported by the middle-aged subjects may be due mainly to difficulty maintaining sleep at early times of the circadian day. The compensatory response to sleep deprivation may also be less robust in middle-aged individuals traveling eastbound.

Positive transfer of audiogenic kindling to electrical hippocampal kindling in rats

Audiogenic seizures in genetically susceptible rodents are provoked by intense acoustic stimulations which result in a tonic seizure associated with a short flattening of the EEG. These seizures have been shown to involve primarily brainstem structures. Daily exposure to sound for 30-40 days produced a permanent change in the evoked seizure with development of facial myoclonias, rearing and falling, or of tonic-clonic seizures accompanied by high amplitude cortical spike-and-wave discharges. Kindled audiogenic seizures appear similar to seizures kindled from amygdala or hippocampus, suggesting that repeated auditory stimulations cause a progressive propagation of the epileptic discharge toward limbic structures. To verify this hypothesis, the behavioral and EEG development of electrical hippocampal kindling has been studied in 7 non epileptic controls (NE), 8 acoustic susceptible (AS), and 8 audiogenic kindled rats (KAS). The behavioral and EEG development of the electrical hippocampal kindling was similar in the AS and the NE rats. However, 2 animals in the AS group but no controls exhibited behavioral running and bouncing during the course of hippocampal kindling. In the KAS group, the hippocampal kindling was clearly facilitated as compared to NE and AS: behavioral stage greater than or equal to 5 was reached in a mean of 4 stimulations in KAS versus 30 and 22 stimulations respectively in NE and AS groups. This positive transfer phenomenon suggests that during kindling of audiogenic seizures, epileptic discharge spreads from the brainstem to the forebrain and progressively involves the hippocampus.

Heterotopic pregnancy with discordant ultrasonic appearance of fetal cardiac activity

In an interesting experiment of nature, we observed the discordant onset of fetal cardiac activity between the two gestations of a heterotopic pregnancy. After initially detecting cardiac activity only in the tubal gestational sac, we later observed cardiac activity in the intrauterine sac 6 days after laparoscopic salpingectomy. This case illustrates the variable onset of cardiac activity. We advise expectant management of the intrauterine pregnancy in a heterotopic gestation when cardiac activity is not detected initially in the intrauterine sac.

Corticotropin-releasing hormone-induced seizures in infant rats originate in the amygdala

The neuroanatomical substrate of seizures induced by picomolar amounts of corticotropin-releasing hormone in infant rats was investigated. Electrographic and behavioral phenomena were monitored in 42 rat pups aged 5 to 22 days. Rat pups carried bipolar electrodes implanted in subcortical limbic structures, as well as cortical electrodes and intracerebroventricular cannulae. The administration of corticotropin-releasing hormone produced age-specific seizures within minutes, which correlated with rhythmic amygdala discharges. Paroxysmal hippocampal and cortical discharges developed subsequently in some rats. Corticotropin-releasing hormone-induced electrographic and behavioral seizures originate in the amygdala.

Corpus callosotomy in the lithium-pilocarpine model of seizures and status epilepticus

Section of the corpus callosum (SCC) is a useful surgical therapy in selected types of epilepsy, i.e., tonic, atonic, and intractable generalized convulsive seizures. Experimentally, the effects of SCC have been documented in animal models of focal seizures as well as generalized seizures. The object of this study was to determine the effect of SCC on behavioral and EEG symptomatology in the lithium-pilocarpine model of seizures and status epilepticus in the rat. SCC was well tolerated. Fifty-seven percent of SCC animals never developed status epilepticus, while all control animals developed status epilepticus. None of the SCC animals died after 24 h but 59% of control animals died within 24 h of status. Histology verified the extent of the SCC and demonstrated widespread brain damage in all animals who exhibited status epilepticus after 72 h. SCC was associated with a lesion of hippocampal commissure in 64% of animals in the SCC group. This protective effect was not related to lesion of the skull or the longitudinal sinus. The lesion of the hippocampal commissure may have contributed to the protective effect of SCC, since animals with an isolated lesion of the hippocampal commissure without SCC survived the status and showed an increased latency to seizure and status epilepticus. These data suggest that the lithium-pilocarpine model of status epilepticus may be useful in the study of the mechanism of efficacy of SCC in the treatment of epilepsy.

Section of the corpus callosum in kainic acid induced seizures in rats: behavioral, electroencephalographic and neuropathological study

Clinical and experimental data suggest that the role of corpus callosum in epilepsy includes synchronization, spread, excitation and inhibition. Section of the corpus callosum (SCC) is known to be a useful therapy in selected types of generalized epilepsy, i.e., tonic, atonic and generalized convulsive seizures, but not partial seizures which may be exacerbated by this procedure. The goal of this study was to determine the effect of SCC in the kainic acid (KA) model of limbic seizures in rats. Using several doses of KA (2.5, 5 and 10 mg/kg) injected systemically, we found a potentiation of the behavioral, electrographic and histological effects of KA in the SCC group of animals compared to the sham-operated control rats. A low dose of kainic acid (2.5 and 5 mg/kg) induced status epilepticus in the SCC animals, but not in the sham-operated control rats. These data demonstrate that in the KA model of temporal lobe seizures, SCC not only fails to protect, but actually intensifies seizures. This finding is compatible with the hypothesis that there is an inhibitory influence, via the corpus callosum, of the non epileptic neocortex on its contralateral homologue in the kainic acid model.

Age-related differences in recovery from simulated jet lag

Six healthy young men and eight early middle-aged men were isolated from environmental time cues for 15 days. For the first 6-7 days (one or two nights adaptation, four nights baseline), their sleep and meals were scheduled to approximate their habitual patterns. Their daily routines were then shifted 6 hours earlier by terminating the sixth or seventh sleep episode 6 hours early. The new schedules were followed for the next 8 or 9 days. Important age-related differences in adjustment to this single 6-hour schedule shift were found. For the first 4-day interval after the shift, middle-aged subjects had larger increases of waking time during the sleep period and earlier termination of sleep than young subjects. They also reported larger decreases in alertness and well-being and larger increases in sleepiness, weariness and effort required to perform daily functions. The rate of adjustment of the circadian core temperature rhythm to the new schedule did not differ between groups. These results suggest that the symptoms reported by the middle-aged subjects may be due mainly to difficulty maintaining sleep at early times of the circadian day. The compensatory response to sleep deprivation may also be less robust in middle-aged individuals traveling eastbound.

Dorsal tegmentum kindling in rats

Electrical stimulations were applied daily for 40 days to the dorsal tegmentum in 9 rats through chronically implanted bipolar electrodes. The intensity of current (2 s trains of 50 Hz, 1 ms monophasic square waves) necessary to trigger a full tonic seizure was determined and applied for all further stimulations. Initial stimulations induced a tonic seizure with a low voltage fast electrocorticographic activity. After repeated stimulations, high amplitude spike and wave discharges developed over the cortex, their duration exceeding 50 s at the 40th stimulation. Simultaneously, the tonic seizures evolved into tonic-clonic fits with bilateral myoclonias following the tonic phase. These EEG and behavioral modifications persisted for 30 days after the last stimulus. These results demonstrate that kindling may be obtained from brainstem structures.

[Paroxysmal neurological manifestations disclosing panic attacks]

Thirty-seven patients presented with paroxysmal neurological manifestations attributed to anxiety attacks. The manifestations included loss of consciousness, focal sensorimotor deficits, diffuse dysesthaesiae, visual disorders and tremor. They lasted 10 to 45 minutes and occurred once per day to once per week. Organic pathology was dismissed on the basis of normal examinations and atypical course. In all patients questioning revealed symptoms that were those of acute anxiety. The fact that these attacks took place in suggestive (circumstances e.g. in crowds and car driving), and that they could be induced by challenge tests hyperpnoea, infusion of lactate) suggested that these disorders were consecutive to panic attacks.

Contralateral disappearance of parkinsonian signs after subthalamic hematoma

A man with Parkinson's disease (PD) suddenly developed a left hemiballismus, and the CT showed a hematoma of the right subthalamic nucleus. After the ballistic movements had disappeared, akinesia and the other parkinsonian signs did not reappear on the left. This clinical case confirms the involvement of the subthalamic nucleus in the akinesia of PD, as suggested by recent experimental data.

Quantitative autoradiography of tyrosine hydroxylase immunoreactivity in the rat brain

Levels of tyrosine hydroxylase (TH) were quantified in discrete areas of unfixed rat brain tissue sections using a rapid and sensitive radioimmunohistochemical method. The immunological reaction with the TH monoclonal antibody was revealed by a 35S-labelled secondary antibody and thus permitted autoradiographic detection of the enzyme. Autoradiograms were generated by apposition of tissue sections to high-sensitivity films or by dipping into autoradiographic emulsion. A detailed analysis of antibody concentration, incubation time, tissue section thickness, and exposure time of the film was undertaken to determine optimal conditions to produce a linear radiolabelling intensity with respect to the amount of antigen. Quantification of the antigen at regional levels was assessed by computer-assisted image analysis. Autoradiographic optical density of radiolabelling in brain areas was converted to enzyme concentrations by interpolation with a constructed TH calibration curve processed in parallel with tissue sections. The specificity of the labelling and the validity and reproducibility of the quantification were investigated. The distribution of TH radiolabelling was comparable to that described using immunofluorescence histochemistry or measuring TH enzymatic activity on homogenates. Using a 35S-labelled antibody, the detection of TH could be performed at the cellular level.

The management of traumatic aortic tear in the multiply-injured patient

Patients with traumatic aortic tears and severe life-threatening associated injuries require early and expeditious evaluation and treatment in order to improve survival. Diagnostic and treatment priorities, however, are not clearly established in this subset of patients. The purpose of this retrospective analysis was to help identify successful diagnostic and treatment priorities in this group of patients. Between 1979-1989 the medical records of all patients sustaining blunt chest trauma resulting in a traumatic aortic tear were reviewed. There were 11 patients with multiple injuries and this diagnosis was treated at Boston University Medical Center. Five patients had diagnostic peritoneal lavage or an exploratory laparotomy prior to a thoracotomy. Four patients had only a thoracotomy. Two patients in this series had a thoracotomy prior to treatment of suspected intraabdominal injuries. One of these two patients died. Our overall survival rate was 82%. This series suggests that the management sequence in patients with coexistent injuries should include treatment of severe associated injuries prior to treatment of the aortic injury and that initial treatment of traumatic aortic tears is appropriate if there is no evidence of severe life-threatening trauma.

Neuronal localization of copper-zinc superoxide dismutase protein and mRNA within the human hippocampus from control and Alzheimer's disease brains

The distribution of cells containing copper-zinc superoxide dismutase (CuZn SOD) protein and mRNA was studied in hippocampi from normal humans and patients with Alzheimer's disease (AD) by using immunohistochemistry and in situ hybridization. Using antisera against native and denatured CuZn SOD protein, we have determined that immunostaining was intense in pyramidal neurons of the cornu ammonis, in granule cells of the dentate gyrus and very weak in other cells. In the hippocampus of an Alzheimer's patient, successive immunostaining of the same tissue section by antiCuZn SOD and antipaired helical filaments antisera show that both normal and degenerating cells were labeled by the antiCuZn SOD antiserum. Thus, large pyramidal neurons which are susceptible to degenerative processes in AD have the property to contain high amount of CuZn SOD protein. In situ hybridization was performed on paraformaldehyde-fixed hippocampus sections of normal human brains and AD brains with a 35 S labeled DNA probe homologous to human CuZn SOD mRNA. Our results show that CuZn SOD transcripts are present at high abundance in pyramidal neurons of the CA1-CA4 fields, subiculum, and in granule cells of the dentate gyrus. This cellular distribution is similar to that obtained with the antiCuZn SOD antiserum. This might indicate that biochemical pathways leading to superoxide radicals generation are specially active in these neurons, requiring an active transcription of CuZn-SOD gene.

Landau-Kleffner syndrome: a pharmacologic study of five cases

Five children with Landau-Kleffner syndrome (epilepsy, acquired aphasia, and continuous spike-wave discharges during sleep), were treated with antiepileptic drugs (AEDs), sleep-modifying drugs, and corticosteroids. The pharmacologic profiles differed from those observed in focal epilepsies, resembling instead those of certain generalized epilepsies, such as West or Lennox-Gastaut syndromes. Phenobarbital (PB), carbamazepine (CBZ), and phenytoin (PHT) were ineffective or worsened the EEG and neuropsychological symptoms, whereas valproate (VPA), ethosuximide (ESM), and benzodiazepines were partially or transiently efficacious. Dextroamphetamine produced a dramatic but transient improvement in waking and sleep EEG in one of two children; aphasia did not change. Corticosteroid treatment resulted in improved speech, suppression of seizures, and normalization of the EEG in three of three children. Our own experience and data from the literature suggest that corticosteroids should be given in high doses as soon as the diagnosis is firmly established and should be continued in maintenance dose for several months or years to avoid escape. Early diagnosis, before mutism or global deterioration develops, appears to be essential for effective therapy with minimal neuropsychological sequelae.

Cerebral glucose utilization during sleep in Landau-Kleffner syndrome: a PET study

Three right-handed male children (aged 5, 6, and 11 years) with signs, symptoms and/or history of the syndrome of acquired aphasia-epilepsy (Landau-Kleffner syndrome) were studied during drug-induced, electroencephalographically (EEG)-monitored sleep by positron-emission tomography (PET) and the [18F]fluorodeoxyglucose (FDG) method. Our data demonstrate that in Landau-Kleffner syndrome, cerebral glucose utilization is not normal during sleep. The metabolic pattern varied between the children but the metabolic disturbances always predominated over the temporal lobes. They were right-sided, left-sided, or bilateral. In the two first patients, EEG recordings showed continuous spike-and-wave discharges during sleep and a right-greater-than-left asymmetry was observed in temporal areas. In patient 1, the asymmetry was associated with a relative increase of glucose utilization of the right posterior temporal region. In patient 2, the glucose utilization was relatively decreased in the left anterotemporal and left perisylvian regions. In patient 3, the sleep EEG showed no discharge and no significant asymmetry was observed; however, glucose utilization of both temporal lobes was decreased. Lower metabolic rates in subcortical structures than in cortex were also noted in the three children. This metabolic pattern may be related to the maturation of the central nervous system (CNS).

Landau-Kleffner syndrome: a clinical and EEG study of five cases

In five children with normal initial psychomotor development, a Landau-Kleffner syndrome appeared at age 3-7 years. No neuroanatomic lesions were noted. Aphasia and hyperkinesia were isolated in three patients and associated with global regression of higher cortical functions in one patient. Massive intellectual deterioration and psychotic behavior were associated with transient aphasia in one patient. The epilepsy (focal motor and generalized tonic-clonic seizures, subclinical EEG focal seizures during sleep, and atypical absences) always regressed spontaneously or with antiepileptic drug (AED) treatment. The EEG in waking patients showed focal and generalized spike-wave discharges on a normal background rhythm. Discharge topography and pattern changed frequently. During sleep, discharges always increased. At some time during syndrome development, all patients had bilateral spike-waves for greater than 85% of the sleep period, while at other times the discharges were discontinuous or continuous but focal or unilaterally hemispheric. Discharge topography and abundance changed from night to night. The abnormal EEG and the impaired higher functions developed and regressed together, but not with strict temporal correlation. Our own experience suggests that the Landau-Kleffner syndrome and epilepsy with continuous spike-wave activity in slow-wave sleep cannot be clearly differentiated. They may be different points on the spectrum of a single syndrome.

[Beta-blockers and migraine. Efficacy of time-release propranolol versus placebo]

The efficacy and safety of long-acting propranolol (LA.P) 160 mg once-daily in the prophylactic treatment of migraine were tested against placebo in a multicentric, double-blind, randomized study comparing the two groups in a parallel manner over a treatment period of 12 weeks, and following a 4 week-placebo run-in period. Fifty-five out of the 74 patients who entered the trial included at the end of the run-in period. Forty-one patients completed the study. Out of the 14 patients who withdrew from the study, none discontinued because of side-effects. The statistical analysis was done according to the "intention to treat" principle. LA.P was significantly more efficient than placebo in reducing the frequency of migraine attacks (p = 0.01 by variance analysis). LA.P reduced the average number of monthly crises by 48% on day 84. There was a slight but significant reduction of the systolic blood pressure and heart rate in the erect position. There was no significant difference between LA.P and placebo regarding either the number of complaints or the number of side-effects elicited out of an 17 item questionnaire. None of the observed side effects led to a withdrawal of treatment.

Diagnostic of precipitant for biomacromolecule crystallization by quasi-elastic light-scattering

The translational diffusion coefficient D25,w of hen egg-white lysozyme and concanavalin A from the jack bean is measured in various precipitating agent solutions as a function of salt and protein concentration using quasi-elastic light-scattering. With some precipitants, in undersaturated protein solutions, a protein or salt concentration dependence of the diffusion coefficient of the scatters is observed. It can be correlated with the inability of the protein to crystallize in this precipitant once the solution is supersaturated. These variations of D25,w are interpreted in terms of non-specific interactions and/or aggregation that prevent the protein from making appropriate contacts to form a crystal. With other precipitants known to lead to crystallization, no significant variation of the diffusion coefficient with increasing concentration was observed, indicating that under such conditions up to saturation the proteins remain essentially monodisperse. Application of this technique to find crystallization conditions of other proteins is discussed.