PURPOSE: We wished to determine the predictive significance of unilateral hippocampal atrophy and interictal spikes on localization of ictal scalp EEG changes and assess whether ictal EEG provides information that might change treatment or influence prognosis in patients with such characteristics of epilepsy. METHODS: We analyzed EEG seizure patterns in 118 seizures in 24 patients with unilateral mesial temporal lobe epilepsy (MTLE) defined by typical clinical seizure semiology, unilateral hippocampal atrophy on magnetic resonance imaging (MRI) and unitemporal spikes on interictal EEG. Two blinded electroencephalographers independently determined morphology, location, and time course of ictal EEG changes. RESULTS: Lateralization was possible in 88.4-92.0% of seizures and always corresponded to the side of the interictal spike focus and of hippocampal atrophy on MRI. Although only 30.4-33.9% of seizures were lateralized at onset, a later significant pattern emerged (12.6-13.3 s after EEG seizure onset) that allowed lateralization in 82.4-91.0% of seizures with nonlateralized onset. Interobserver reliability for lateralization was excellent, with a K-value of 0.85. In most patients, either all (79.2-83.3%) or >50% (8.3-16.7%) of seizures were lateralized. In only a small proportion of patients (4.2-8.3%) were <50% of seizures lateralized. In 1 patient, no seizure could be lateralized by 1 electroencephalographer. The results of ictal EEG recordings did not alter the surgical approach and did not correlate with surgical outcome. CONCLUSIONS: We conclude that unilateral hippocampal atrophy on MRI and unitemporal interictal spikes can predict localization of ictal scalp EEG changes with a high degree of reliability and that ictal EEG provides no additional localizing information in this particular patient group.

Adult↗

PubMed1998

Mechanical integrity of subchondral bone in osteochondral autografts and allografts.

OBJECTIVE: To assess the influence of osteochondral graft preservation techniques on post-transplant biomechanics of graft and host subchondral bone in the knee joint. DESIGN: An experimental animal model (sheep), specifically the weight-bearing articular surface of the medial femoral condyle of the knee joints. INTERVENTION: Each sheep received, in the ipsilateral knee, an allograft that was (a) frozen without dimethyl sulfoxide (DMSO), (b) snap-frozen in liquid nitrogen or (c) frozen with DMSO. The contralateral knee received an autograft that was (a) snap-frozen, (b) treated with DMSO or (c) left untreated (fresh). MAIN OUTCOME MEASURES: Mechanical and material properties of bone, including maximal compression stress, modulus of elasticity and bone cores (from the graft centre and surrounding host bone). RESULTS: No significant differences were found in the mechanical properties of the subchondral bone under the graft, but there were significant changes in surrounding bone. Bone surrounding the grafts that were snap-frozen or frozen without DMSO was significantly stronger than the normal control bone. However, bone surrounding fresh autografts and cryoprotected allografts was not significantly different from normal control bone. CONCLUSIONS; The changes in the mechanical behaviour of the host bone may be associated with graft cell viability. The great stiffness of the subchondral host bone may have consequences for long-term graft integrity and for the development of degenerative osteoarthritis.

Animals↗

PubMed1996

Paroxetine as a treatment for premenstrual dysphoric disorder.

Research into the psychobiology of premenstrual dysphoric disorder (PDD) finds alterations in markers associated with serotonergic neurotransmission. Supporting this is work showing that patients with PDD respond to some agents that block the reuptake of serotonin. In this open trial, patients were treated for one cycle with placebo and then for three consecutive cycles with the serotonin reuptake inhibitor paroxetine. The study population was composed of 14 participants who met DSM-IV criteria for PDD with moderate to severe symptomatology and specifically endorsed anger and irritability as a central premenstrual complaint. Patients showed modest improvement over the course of the pretreatment evaluation, with significant improvement occurring for feelings of worthlessness, decreased interest, and low energy. The effects of active treatment were marked by the first active cycle with luteal phase 17-item Hamilton Rating Scale for Depression scores decreasing from 14.9 (+/- 5.3) to 8.2 (+/- 4.9) in the first, 7.8 (+/- 5.1) in the second, and 7.8 (+/- 6.8) in the third active treatment cycles (F[1,13] = 17.6; p < 0.0001). A group of items from daily ratings indicative of anger and irritability (mood swings, anger and irritability, behavioral dyscontrol, and interpersonal conflicts) also showed improvement (F[1,13] = 5.94; p < 0.03). Various definitions of response were applied to treatment completers. The most conservative measure, the Clinical Global Impression (CGI), revealed that 7 of 14 patients had a complete response (CGI = 1 or 2) whereas 4 patients had a partial response (CGI = 3). These open trial findings are consistent with the notion that paroxetine is effective in the acute phase for the treatment of PDD.

Adult↗

PubMed1996

Supplementary motor area seizures: propagation pathways as studied with invasive recordings.

We studied propagation of epileptic discharges in five patients with supplementary motor area (SMA) seizures with subdural grid electrodes implanted over the dorsolateral frontal neocortex and in the interhemispheric fissure. We found that both interictal and ictal epileptic discharges occurred synchronously in the SMA and the primary cortex. The actively involved electrodes were separated by silent electrodes. The time lag between the SMA and the primary motor cortex averaged 25 msec for interictal and 100 msec for ictal discharges. Cortical stimulations of the affected electrodes showed motor effects in corresponding body parts. All patients underwent resections of the EEG onset zone within the SMA while sparing the primary motor cortex and experienced a significant (>90%) reduction of seizure frequency. We conclude that epileptic activity is propagated between the SMA and the primary motor cortex by a somatotopically organized monosynaptic pathway.

Adolescent↗

PubMed1996

Epileptic negative myoclonus: An EEG-single-photon emission CT study indicating involvement of premotor cortex.

We report a combined EEG-single-photon emission CT (SPECT) study on a patient with epileptic negative myoclonus (ENM). Clinically, the ENM was characterized by brief repetitive lapses in postural tone of the right upper extremity when the arms were held outstretched, whereas no movement effect was observed during rest. Ictal EEG showed repetitive left frontal spikes with a maximum at electrodes EC1 and F1. EMG silent periods lasting from 100 to 200 ms followed the onset of the EEG transients by a latency of 20 to 40 ms. The N20 component of median nerve somatosensory evoked potentials-representing a biological marker of the location of central fissure-showed a phase reversal between electrodes P3 and C1 and thus was located considerably posterior to the spike maximum. We obtained accurate anatomic reference of cerebral blood flow changes visible on SPECT by a special coregistration technique of MRI and SPECT. SPECT performed during ENM showed a marked regional hyperperfusion in the left middle frontal gyrus and a less pronounced increase in tracer uptake in the left supramarginal gyrus. Our results suggest that ENM is generated by epileptic activity in the premotor area in the middle frontal gyrus corresponding to Brodmann's area 6.

Adolescent↗

PubMed1995

Atrial natriuretic factor release during pregnancy in rats.

1. We investigated the control of atrial natriuretic factor (ANF) secretion during pregnancy. 2. Plasma ANF levels were measured in conscious virgin female rats under basal conditions, and after atrial distension with an indwelling balloon catheter. The rats were then mated, and the measurements repeated at 7, 14 and 21 days of pregnancy, and at 1 week postpartum. Plasma ANF levels were also measured in ovariectomized rats injected with progesterone, oestradiol, or oestradiol plus progesterone. 3. Basal plasma ANF levels were elevated at 7 and 14 days of pregnancy, but returned to prepregnant levels by 21 days. At 1 week postpartum, they were again elevated. 4. In response to atrial stretch, plasma ANF increased significantly in virgin rats (from 100 +/- 10 to 148 +/- 13 pg ml-1, P < 0.001, n = 20). In contrast, there was no such secretory response observed in the pregnant and postpartum animals i.e. stretch-induced secretion of ANF was markedly attenuated. 5. Treatment with exogenous oestradiol caused a significant increase in plasma ANF levels in acyclic rats. However, neither progesterone nor a combination of oestradiol plus progesterone had any effect. 6. It is concluded that basal and stretch-induced ANF secretion are differentially influenced by pregnancy; oestradiol is identified as a potential stimulatory factor.

Animals↗

PubMed1995

Familial inverted duplication 7p.

A 10-month-old female with developmental delay and failure to thrive was referred for genetic evaluation as part of an adoption assessment. Physical exam showed a mildly beaked nose and clinodactyly, but otherwise nothing remarkable. Chromosome analysis showed an inverted duplication of the p12.2-->p13 portion of chromosome 7[(46,XX, dup(7)(p13p12.2)]. The proposita's older brother, mother, and grandmother were cognitively delayed and had the same chromosome 7 duplication. A review of the literature showed no other cases involving this exact duplication.

Chromosome Inversion↗

PubMed1995

Age and dose-related effects of hippocampal ibotenic acid on lesion size, mortality, and nonspatial working memory in infant rats.

Three experiments are presented in which the neural and behavioral consequences of multiple ibotenic acid (IBO) injections into the hippocampus were examined in Sprague-Dawley rat pups. Rat pups were 11 or 15 days of age at the time of surgery (SURG11, SURG15), the dose of IBO was either 1 microgram in 1 microliter, 2.5 micrograms in 0.5 microliters, or 5 micrograms in 1 microliter for each of four injections, and pups were allowed to survive for 3 or 7 days after the lesion was made. The Fink-Heimer silver stain was used in Experiment 1 to examine the extent of neural damage following unilateral lesions and showed that the degeneration was primarily located in the hippocampus. The magnitude of the damage was greatest in younger pups and in those which received the higher of the two concentrations (injection volume was not a factor). Degenerating fibers were seen in the columns of the fornix as well as precommissural fornix fibers, but only in SURG15 animals when damage extended into the dorsal subiculum. Mortality rates following multiple IBO injections were very high in infant rats, in some cases as high as 60%. Experiments 2 and 3 examined the effects of bilateral lesions on neuroanatomy and behavior. Bilateral lesions were somewhat smaller than unilateral lesions, and as for unilateral lesions, degeneration in pre- and postcommissural fornix was seen only in SURG15 animals. The behavioral task used in Experiments 2 and 3 was patterned single alteration, a memory-based appetitive learning discrimination. Earlier work has shown that damage to the infant hippocampus results in moderate deficits in this task at 30-s intervals and more substantial deficits at 60-s intertrial intervals. This was not the case in the present studies: regardless of age at surgery or time postlesion, all infant rats tested learned this discrimination at the two intertrial intervals. As has been recently reported for adult rats, excitotoxic lesions of the hippocampus in infant rats do not produce the same patterns of behavioral deficits as electrolytic lesions.

Age Factors↗