Anti-interleukin-10R1 monoclonal antibody in combination with bacillus Calmette--Guérin is protective against bladder cancer metastasis in a murine orthotopic tumour model and demonstrates systemic specific anti-tumour immunity

Effective treatment of bladder cancer with bacillus Calmette-Guérin (BCG) depends on the induction of a T helper type (Th) 1 immune response. Interleukin (IL)-10 down-regulates the Th1 response and is associated with BCG failure. In this study, we investigated whether blocking IL-10 signalling could enhance the BCG-induced Th1 response and anti-tumour immunity in a murine orthotopic tumour model. Treatment with BCG and anti-IL-10 receptor 1 monoclonal antibody (anti-IL-10R1 mAb) increased the interferon (IFN)-γ to IL-10 ratio in both splenocyte cultures and urine. Mice bearing luciferase-expressing MB49 (MB49-Luc) tumours were treated and followed for tumour growth by bioluminescent imaging, bladder weight and histology. Mice treated with phosphate-buffered saline (PBS) (group 1), BCG plus control immunoglobulin (Ig)G1 (group 2) or BCG plus anti-IL-10R1 mAb (group 3) showed 0, 6 and 22% tumour regression, respectively. The mean bladder weight of group 3 mice was substantially lower than those of groups 1 and 2 mice. Remarkably, 36% of group 1 and 53% of group 2 mice but no group 3 mice developed lung metastasis (P = 0·02). To investigate the mechanisms underlying the effect of combination therapy, splenocytes were stimulated with S12 peptide (serine mutation at codon 12 of the K-ras oncogene) known to be expressed in MB49-Luc cells. Induction of ras mutation-specific IFN-γ and cytotoxicity was observed in mice treated with combination therapy. These observations indicate that BCG, in combination with anti-IL-10R1 mAb, induces enhanced anti-tumour immunity that is protective against lung metastasis. Anti-IL-10R1 mAb demonstrates systemic effects and may prove useful in clinical practice for treating bladder cancer in high-risk patients.

Idiopathic generalised epilepsy of adult onset: clinical syndromes and genetics

OBJECTIVE

To study the clinical features and genetics of idiopathic generalised epilepsy (IGE) beginning in adult life.

METHODS

Consecutive patients with IGE, defined as generalised seizures with spike or polyspike and wave on EEG, were studied in the setting of a first seizure clinic where an early postictal EEG record is part of the protocol. Patients were divided into two groups: "classical IGE" with onset before 20 years and inclusive of all the IGE subsyndromes recognised by the international classification; and "adult onset IGE", when seizure onset was at age 20 years or later. Seizure patterns, clinical features, and genetics of the adult onset group were examined.

RESULTS

Of 121 patients with an electro-clinical diagnosis of IGE, 34 (28%) were diagnosed as adult onset IGE. The seizure patterns in these 34 cases were tonic-clonic seizures + absences (3), tonic-clonic seizures + myoclonus (6), and tonic-clonic seizures alone (25). Tonic-clonic seizures were often precipitated by alcohol or sleep deprivation. The proportion of affected first and second degree relatives did not differ between the classical and adult onset IGE groups. Twenty adult onset cases were treated with sodium valproate, four with other antiepileptic drugs, and 10 were untreated. Follow up of 32 of the 34 cases (for 31 (22) months (mean (SD)) showed that tonic-clonic seizures recurred in eight patients: five with identified provocative factors and three without.

CONCLUSIONS

Adult onset IGE is a relatively frequent and benign disorder. Seizures are usually provoked and are easy to control. Patients in this age group may often be misdiagnosed as having non-lesional partial epilepsy. Early postictal EEG and sleep deprivation studies may improve the detection of these patients. Pedigree analysis suggests that adult onset IGE, like classical IGE, has a genetic aetiology.

Nonenhanced limited CT in children suspected of having appendicitis: prospective comparison of attending and resident interpretations

PURPOSE

To prospectively compare resident and attending radiologic interpretations of nonenhanced limited computed tomographic (CT) scans obtained in children suspected of having appendicitis.

MATERIALS AND METHODS

Seventy-five consecutive children underwent nonenhanced limited CT for suspected appendicitis. The scans were prospectively interpreted by a resident and an attending radiologist, each unaware of the other's interpretation. The probability that the findings indicated a diagnosis of appendicitis, level of certainty in the interpretation, and presence of an alternate diagnosis were statistically analyzed.

RESULTS

Nineteen children (25%) had appendicitis. The area under the receiver operating characteristic curve was not significantly different between residents (0.97 +/- 0.02) and attendings (0.95 +/- 0.04). The percentage agreement between residents and attendings was 91% (kappa = 0.73 +/- 0.095). The average level of certainty tended to be higher for attendings (93% +/- 15) than residents (89% +/- 12). The sensitivity, specificity, and accuracy of resident interpretations were 63%, 96%, and 88%, respectively, compared with those of attending interpretations--95%, 98%, and 97%, respectively. Residents and attendings noted alternate diagnoses in 30% of children without appendicitis.

CONCLUSION

A high level of agreement exists between resident and attending radiologists in the interpretation of nonenhanced limited CT scans in children suspected of having appendicitis. Residents, however, tend to be less confident in their interpretations.

Prolonged cortical silent period after transcranial magnetic stimulation in generalized epilepsy

Transcranial magnetic stimulation (TMS) produces a cortical silent period (CSP) during a voluntary contraction. The duration of the CSP was used to assess the level of intracortical inhibition in patients with untreated idiopathic generalized epilepsy (IGE). Mean CSP duration was assessed at three TMS stimuli in 21 patients with IGE compared with 19 normal control subjects. Mean CSP duration was increased at all stimulus intensities, indicating that intracortical inhibition is increased in patients with IGE.

Hippocampal sclerosis following brief generalized seizures in adulthood

This report describes a patient who had a first generalized tonic clonic seizure (GTCS) at the age of 18 years. The initial MRI scan was normal on visual and quantitative examination. After a further six GTCS, a second MRI scan showed reduced hippocampal volume and increased hippocampal T2 signal, which was confirmed in a third scan. Therefore, hippocampal sclerosis may be acquired in adulthood after brief GTCS.

Ictal SPECT and interictal PET in the localization of occipital lobe epilepsy

PURPOSE

To compare the localizing value of ictal single photon emission computed tomography (SPECT) and interictal fluorodeoxyglucose-positron emission tomography (FDG-PET) in refractory occipital lobe epilepsy.

METHODS

Six patients who underwent surgery for refractory epilepsy associated with pathology in the occipital lobe were retrospectively selected from records of the Austin & Repatriation Centre Comprehensive Epilepsy Programme. Interictal SPECT and PET and ictal SPECT were obtained by standard methods. All studies were read by a nuclear medicine expert blinded to clinical data except the diagnosis of epilepsy.

RESULTS

Ictal SPECT showed unilateral occipital hyperperfusion in five of six cases often accompanied by temporal lobe hyperperfusion. These patterns were seen in cases with or without magnetic resonance imaging (MRI) abnormality. Interictal SPECT was not localizing in any case, in contrast to PET, which showed occipital hypometabolism in three of five studies.

CONCLUSIONS

Ictal SPECT can provide novel localizing data in MRI-negative occipital lobe epilepsy. Interictal PET can provide useful localizing information, but its role in providing novel information was not demonstrated. Interictal SPECT is useful only as a baseline to aid in interpretation of ictal studies.

Benign partial seizures of adolescence

PURPOSE

A benign syndrome of partial seizures in adolescents (BPSA) was described by Loiseau et al. in 1978, but confirmation of this syndrome has been lacking. We sought to identify BPSA among teenagers with new-onset focal seizures enrolled in our prospective first-seizure study and to assess the EEG and magnetic resonance imaging (MRI) findings.

METHODS

We searched the study database for patients aged between 10 and 20 years with focal seizures who did not have idiopathic partial epilepsies, epileptogenic lesions on MRI, or recurrent tonic-clonic seizures during 2 years of follow-up.

RESULTS

The database contained 92 adolescents, including 37 with partial epilepsy, of whom eight (22%) patients matched the description of BPSA. All eight patients had seizures with a sensory/motor "march." Six had a secondarily generalized seizure and two had simple partial seizures alone. Epileptiform abnormalities were documented in five cases but lacked a distinctive morphology or distribution. No lesions were seen on MRI.

CONCLUSIONS

BPSA can be provisionally diagnosed in teenagers with unprovoked focal seizures characterized by a march of sensory/motor symptoms, whose MRI is normal. The psychosocial consequences of chronic epilepsy in adolescence are considerable, so early recognition of this benign syndrome is important.

Epileptology of the first-seizure presentation: a clinical, electroencephalographic, and magnetic resonance imaging study of 300 consecutive patients

BACKGROUND

Prognosis and treatment of the first seizure depends on identification of a specific epilepsy syndrome, yet patients with first seizures are generally regarded as a homogeneous group. We studied whether it is possible to diagnose specific epilepsy syndromes promptly by use of standard clinical methods, electroencephalography (EEG) and magnetic resonance imaging (MRI).

METHODS

300 consecutive adults and children presented with unexplained seizures. We systematically collected clinical data from patients and witnesses, and attempted to obtain an EEG within 24 h of the seizure. Where the EEG was negative, a sleep-deprived EEG was done. MRI was done electively.

FINDINGS

A generalised or partial epilepsy syndrome was clinically diagnosed in 141 (47%) patients. Subsequent analysis showed that only three of these clinical diagnoses were incorrect. Addition of the EEG data enabled us to diagnose an epilepsy syndrome in 232 (77%) patients. EEG within 24 h was more useful in diagnosis of epileptiform abnormalities than later EEG (51 vs 34%). Neuroimaging showed 38 epileptogenic lesions, including 17 tumours. There were no lesions in patients for whom generalised epilepsy was confirmed by EEG. Our final diagnoses were: generalised epilepsy (23% of patients); partial epilepsy (58%); and unclassified (19%).

INTERPRETATION

An epilepsy syndrome can be diagnosed in most first-seizure patients. Ideally, an EEG should be obtained within 24 h of the seizure followed by a sleep deprived EEG if necessary. MRI aids diagnosis and should be done for all patients except for those with idiopathic generalised epilepsies and for children with benign rolandic epilepsy.

Determinants of density- and frequency-dependent fitness in competing plant pathogens

ABSTRACT Using mathematical models, we investigated how infection and sporulation characteristics of competing plant pathogens determine the density and frequency dependence of relative fitness. Two models, one for the infection stage and one for the sporulation stage of a pathogen's life cycle, describe reproductive output of pathogen strains in mixture as a function of the strains' population densities. Model parameters include infection and sporulation efficiencies, carrying capacities on leaves for sporulating lesions and spore production, and coefficients of interstrain competitive effects in both life cycle stages. Although the models were originally developed for rust fungi, they are generally applicable to any organism with distinct colonization (e.g., infection) and propagative (e.g., sporulation) life cycle stages. In this work, paired hypothetical strains were assigned equal baseline parameter values. Parameters were then altered one at a time for one or both strains, and relative fitness was calculated over a range of densities and strain frequencies. Except for infection efficiency, the fitness benefit conferred by an advantage in a single parameter was always density dependent. Relative fitness was frequency dependent whenever inter- and intrastrain competitive effects were not equal. These results suggest that the fitness of pathogens in nature is rarely fixed, but, rather, may typically be highly dependent on the densities and frequencies of all coexisting strains in a habitat.

Perfusion patterns during temporal lobe seizures: relationship to surgical outcome

We sought to determine whether patterns of ictal hyperfusion demonstrated using [99mTC]HMPAO (hexamethylpropylene amine oxime) single photon emission computed tomography (SPECT) predict outcome of temporal lobectomy; in particular, whether the more extensive patterns of ictal hyperperfusion are associated with poor outcome. We studied 63 patients who had ictal SPECT studies prior to temporal lobectomy. Hyperperfusion on ictal SPECT scans was lateralized, and classified into: (i) 'typical', (ii) 'typical with posterior extension', (iii) 'bilateral' and (iv) 'atypical' patterns. Outcome (minimum of 2 years follow-up) was classified as either seizure free, or not seizure free. Actuarial analysis was used to test the relationship of SPECT patterns with outcome. There were 35 cases with the typical ictal SPECT pattern, 13 posterior, nine bilateral and six atypical cases. The atypical pattern was associated with lack of pathology in the surgical specimen. Outcome was similar for the typical, posterior and bilateral with 60%, 69% and 67% seizure free, respectively. In contrast, the atypical group had a worse outcome with only 33% seizure free. Actuarial analysis showed a significant difference in outcome between patients with the typical pattern, and patients with the atypical pattern (P = 0.04). We conclude that extended patterns of ictal perfusion in temporal lobe epilepsy do not predict poor outcome, indicating that extended hyperperfusion probably represents seizure propagation pathways rather than intrinsically epileptogenic tissue. Atypical patterns of hyperperfusion are associated with poor outcome and may indicate diffuse or extra-temporal epileptogenicity.

Cytokine gene expression in pancreatic islet grafts in the rat

We examined the production of cytokine message in allogeneic and syngeneic rat pancreatic islet grafts using specific primers and polymerase chain reaction. Freshly isolated islet preparations contained transcripts for interleukin (IL)-1alpha, IL-6, IL-10, and interferon-gamma (IFN-gamma) but not for IL-2. IL-1alpha in allogeneic grafts showed increased and consistently high expression from 1 to 7 days after transplantation, but the level in syngeneic grafts fell quickly to pretransplant levels. IL-2 and IFN-gamma transcripts were found in allogeneic grafts at 1, 3, 5, and 7 days after transplantation with a peak at day 5, but these cytokines were almost absent from syngeneic grafts. The peak of IL-6 expression was 1 day after transplantation in both syngeneic and allogeneic grafts, and then the level fell quickly. IL-10 was produced at approximately the same high level at all time points in both syngeneic and allogeneic grafts. The results show that freshly isolated islet preparations contain IL-1alpha, IL-6, IL-10, and IFN-gamma transcripts at the time of transplantation. The initial production of cytokines in islet grafts, especially IL-1, may explain phenomena such as graft nonfunction, rapid rejection, and lack of response to immunosuppression.

Hippocampal atrophy is not a major determinant of regional hypometabolism in temporal lobe epilepsy

PURPOSE

The pathophysiologic basis for the [18F]fluorodeoxyglucose positron-emission tomography (FDG-PET) temporal lobe hypometabolism in patients with hippocampal sclerosis (HS) is uncertain. We tested the hypothesis that hippocampal atrophy, which is strongly correlated with hippocampal cell loss, is largely responsible for the regional hypometabolism in HS.

METHODS

Regions of interest (ROIs) on FDG-PET scanning were determined in the medial, lateral, and posterior temporal lobe, thalamus, and basal ganglia. A right/left asymmetry index for each ROI was calculated. These results were correlated with hippocampal magnetic resonance imaging (MRI) volume ratios.

RESULTS

There was no correlation between the magnitudes of the FDG-PET asymmetry index and the MRI volume ratio for the mesial or lateral temporal regions (r = -0.09, r = -0.04). When the right/left asymmetry index was compared with the right/left hippocampal volume ratio, correlations for the mesial temporal ROI (r = 0.79, p < 0.0001) and lateral temporal ROI (r = 0.57, p < 0.0005) were found. These, however, simply indicated that both tests accurately reflect the side of the epileptogenic region. The concordance of the side of relative hypometabolism of the FDG-PET with the side of the hippocampal atrophy was higher for the mesial temporal region (100%) than for the lateral (77.5%).

CONCLUSIONS

The lack of correlation between the magnitudes of the ratios argues against hippocampal atrophy and cell loss having a central role in the FDG-PET temporal hypometabolism.

Plasmapheresis in Rasmussen's encephalitis

Rasmussen's encephalitis (RE) is a progressive childhood disorder characterized by intractable focal seizures, hemiplegia, dementia, and inflammatory histopathology. The process is typically limited to one cerebral hemisphere. We report four patients with pathologically confirmed RE who were treated with repeated plasmapheresis. Three patients exhibited repeated, dramatic, transient responses to plasmapheresis, manifested by reduced seizure frequency and improved neurologic function. One patient exhibited marginal improvement after treatment with plasmapheresis. These observations indicate that circulating factors, likely autoantibodies, are pathogenic in at least some patients with RE and suggest that RE is an autoimmune disease. Plasmapheresis may be a useful adjunctive therapy in status epilepticus, and can also aid in assessment of residual function in the diseased hemisphere before surgical resection.

Comparative localisation of CRYP alpha, a CAM-like tyrosine phosphatase, and NgCAM in the developing chick visual system

The avian CRYP alpha gene is expressed in the embryonic nervous system and encodes a receptor-like protein tyrosine phosphatase with structural similarity to neural cell adhesion molecules. To gain further insight into the role of the CRYP alpha phosphatase in neural development, this study addresses the protein's cellular distribution in the well characterised embryonic visual system. High levels of CRYP alpha protein localise in retinal axons extending from the eye to the tectum throughout the major growth periods of these nerve processes. In addition, primitive inner plexiform layer processes in the retina, tectobulbar axons, and non-retinal fibres of the tectal stratum opticum, contain large amounts of CRYP alpha. Its presence in non-fasciculated processes suggests that CRYP alpha has a role other than in fasciculation in short range fibres. In contrast to CRYP alpha, NgCAM is confined largely to axon fascicles in the retina and tectum, consistent with its demonstrated role in fasciculation of cultured neurites. In cultured retinal neurons CRYP alpha proteins reside both in neurite processes and in growth cone membranes, implicating both of these as potential functional locations for the protein. Although CRYP alpha continues to be expressed in the later embryo, the strong, early expression suggests a significant developmental role in the initial growth or guidance of nerve processes. This applies both over the longer range in the retinotectal and tectobulbar projections and over the shorter range within plexiform layers.

SPECT in the localisation of extratemporal and temporal seizure foci

The yield of ictal, postictal, and interictal SPECT was compared in the localisation of seizure foci in 177 patients with partial epilepsy. In 119 patients with known unilateral temporal lobe epilepsy ictal SPECT (97% correct localisation) was superior to postictal SPECT (71% correct), which was better than interictal studies (48% correct). Similarly, in cases of known or suspected extratemporal epilepsy the yield of ictal SPECT studies was high (92%). By contrast, the yield of postictal studies was much lower (46%) and usually only very early postictal studies were diagnostic. Interictal SPECT was of little value. The accuracy of ictal SPECT in localising temporal lobe seizures is now well established. Extratemporal seizures are often brief and difficult to localise. This report shows that ictal SPECT also has a high diagnostic yield in a wide range of extratemporal epilepsies. The brevity of many extratemporal seizures means that true ictal SPECT examinations can be difficult to achieve, but the high diagnostic yield justifies the special organisational effort needed to obtain such studies.

Comparison of ictal SPECT and interictal PET in the presurgical evaluation of temporal lobe epilepsy

We retrospectively compared ictal technetium 99m hexamethylpropyleneamineoxime single-photon emission computed tomography (SPECT) and interictal 18F-fluorodeoxyglucose positron emission tomography (PET) in 35 patients with well-lateralized temporal lobe epilepsy (TLE). Based on SPECT scans the two observers correctly lateralized seizure foci with certainty in 89% of patients; interobserver agreement was excellent. Both observers incorrectly lateralized the seizure focus on two SPECT scans; one error was explained by rapid electroencephalographic spread to the contralateral side and for the other patient, isotope was injected during a brief aura. Based on PET scans, observers correctly lateralized the foci with certainty in 63% and with lesser confidence in 83%; four incorrect lateralizations were made by one observer and none by the other. PET interobserver disagreement was explained by differences between observers in weighting the relative hypometabolism in medial and lateral temporal regions. The detection rate for PET was lower in the absence of structural imaging abnormalities (60 vs 87%). PET yielded correct lateralizations in the 2 patients for whom SPECT interpretation was difficult. We conclude that both ictal SPECT and interictal PET are sensitive methods for the lateralization of TLE, but SPECT can be interpreted with greater certainty and is more sensitive when magnetic resonance imaging findings are negative. False lateralization is rare with ictal SPECT and can be explained when interpreted in conjunction with electroclinical data. Both investigations have complementary roles when localization is difficult.

Parietal lobe epilepsy: clinical features and seizure localization by ictal SPECT

We studied clinical and ictal single-photon emission computed tomography (SPECT) features in 14 patients with parietal lobe epilepsy, nine of whom had structural parietal lobe lesions. Thirteen patients had simple partial seizures of somatosensory (eight), psychic (four), and motor (nine) types. Complex partial seizures (CPS) occurred in seven patients; six were psychoparetic (prominent staring, relative immobility) and one had hyperkinetic activity. Seizures lasted 7 to 110 seconds; 99mTc-HMPAO (hexamethylpropylene amine oxime) was injected ictally, 7 to 89 seconds from seizure onset and 0 to 74 seconds (mean, 21.0 +/- 24.4 seconds) before seizure termination. Ictal SPECT demonstrated focal areas of parietal hyperperfusion in all 14 cases and corresponded with sites of the structural lesions. Parietal hyperperfusion was anterior in eight, posterior in four, and diffuse in two. Quantitative analysis revealed increases in parietal side-to-side perfusion ratios on ictal compared with interictal scans of 11 to 51% (mean, 25.5 +/- 14.4%). Ictal SPECT localization correlated with two main clinical seizure patterns: an anterior syndrome characterized by sensorimotor manifestations and a posterior syndrome characterized by CPS of the psychoparetic type. Ictal SPECT is helpful for localization of parietal seizures. Parietal hyperperfusion is discrete and short-lived, demanding true ictal injections for diagnostic studies.

Ictal postictal and interictal single-photon emission tomography in the lateralization of temporal lobe epilepsy

Single-photon emission tomography (SPET) using radioligands that are fixed on first pass through the cerebral circulation shows distinctive and rapidly changing blood flow patterns accompanying temporal lobe seizures. We sought to determine the optimal time to perform SPET studies for clinical seizure lateralization in temporal lobe epilepsy. Interictal, ictal and postictal SPET scans of 73 consecutively studied patients with unilateral temporal lobe epilepsy were read by three blinded observers to assess the accuracy of lateralization in each condition. The blinded observers correctly identified the side of focus in 97% of ictal studies, 72% of postictal studies and 50% of interictal studies. No incorrect scores were made in the ictal studies, whilst 5% of postictal and 12% of interictal studies were lateralized to the wrong side. Inter-observer agreement was best with the ictal studies. The dramatic perfusion changes of ictal SPET provide consistent, reliable and easily interpretable information that is superior to that provided by interictal and postictal studies. Injection of ligand during seizures is therefore the method of choice for SPET to aid the non-invasive lateralization of temporal seizure foci.

Ictal SPECT using technetium-99m-HMPAO: methods for rapid preparation and optimal deployment of tracer during spontaneous seizures

Ictal SPECT provides unique information for the clinician treating patients with refractory epilepsy and reveals insights into the pathophysiology of seizures. We describe our methods for the routine attainment of ictal images using 99mTc-HMPAO. We have devised and implemented techniques for rapid reconstitution of 99mTc-HMPAO adjacent to the video-EEG monitoring suite such that the tracer can be rapidly injected into patients when spontaneous seizures occur. Our quality assurance data show that this can be done safely outside a nuclear medicine department. The clinical results in patients with temporal lobe epilepsy show that ictal injections (97% correct lateralization of focus, 0% incorrect) are more sensitive and accurate compared to interictal studies (48% correct, 10% incorrect), demonstrating that the implementation of these techniques is worthwhile.

Comparative IgE responses to extracts of five species of house dust mite, using western blotting

IgE responses towards extracts of Dermatophagoides pteronyssinus, D. farinae, D. microceras, Euroglyphus maynei and Gymnoglyphus longior have been evaluated with sera from a mite sensitive population and the international reference pool of sera, NIBSC 82/528, using Western blotting. Using mite body and faecal extracts 21 of 29 mite protein bands responded to by sera were common to all five species of mite. All sera were unique with respect to proteins bound and species recognized. Mite proteins bound by more than 40% of sera included the Group II and III main allergens and protein bands 14 (MW 40.4 kD) and 21 (MW 27.8 kD), all of which were found in every mite species studied. The Group I allergen, found in all species, was bound by 29.4% of sera. Similar response profiles between mite species suggest that human specific IgE may bind predominantly to crossreactive determinants on mite allergens.

Postictal switch in blood flow distribution and temporal lobe seizures

The ictal increase of regional cerebral blood flow has yet to be fully utilised in the investigation of focal seizures. Although single photon emission tomography (SPECT) is being increasingly used in the localisation of epileptic foci, the evolution and time courses of the peri-ictal perfusion changes have yet to be clarified. We performed serial SPECT studies in the interictal, ictal and immediate postictal states in 12 patients with refractory temporal lobe epilepsy to define the patterns and duration of peri-ictal cerebral blood flow changes. Visual analysis showed a constant pattern of unilateral global increases in temporal lobe perfusion during seizures which suddenly switched to a pattern of relative mesial temporal (hippocampal) hyperperfusion and lateral temporal hypoperfusion in the immediate postictal period. Quantitative analysis confirmed the visual assessment. Lateral temporal cortex ictal/normal side to side ratios were increased by mean 35.1% (95% confidence interval 21.8% to 48.4%) more in the ictal studies than in the interictal studies and mesial temporal cortex ratios increased by mean 30.8% (22.4% to 39.2%). In the postictal state, however, lateral temporal ratios were reduced by mean 7.7% (-15.8% to 0.4%) compared with interictal values, whereas mesial temporal perfusion was maintained compared with the interictal studies. These observations provide critical information for interpreting scans which can be used in the localisation of epileptic foci. This postictal switch in blood flow patterns may reflect the underlying metabolic processes of neuronal activation and recovery and have implications for understanding the neurobiology of human epileptic seizures.

Dystonia, clinical lateralization, and regional blood flow changes in temporal lobe seizures

We analyzed the lateralizing value of ictal dystonia and head-turning in temporal lobe epilepsy, and sought the biologic basis of these clinical signs by studying the regional changes in perfusion with ictal single-photon emission computed tomography (SPECT). We identified unilateral temporal lobe epilepsy in 40 of 42 patients undergoing evaluation for temporal lobe surgery, and with ictal SPECT all 40 showed striking hyperperfusion of the epileptogenic temporal lobe. Twenty-five of the 40 patients showed unilateral or predominantly unilateral upper limb dystonia, which was opposite the epileptic temporal lobe in all cases. Analysis of regional count ratios in cases with ictal dystonia, compared with those without, showed significant changes only in the basal ganglia. Specifically, we found that ictal dystonia was associated with a relative increase in perfusion of the basal ganglia opposite the dystonic limb. Although we found 26 cases with head-turning, the sign was of no lateralizing value, even when only those with major or "tonic" versions (n = 11) were analyzed. Slight increases in cortical blood flow on the side opposite the direction of version were associated with head-turning, irrespective of the side of seizure focus. In clinical practice, ictal SPECT is a highly accurate aid in the lateralization of temporal lobe foci, in addition to providing a new method to investigate the pathophysiology of clinical signs in focal seizures.

A study comparing SPECT with CT and MRI after closed head injury

After closed head injury nineteen patients had single photon emission tomography (SPECT) using the lipophilic tracer 99m-Technetium hexamethyl-propylene-amineoxime (HMPAO) to compare the defects shown by CT and MRI. SPECT showed more focal cerebral lesions than either CT or MRI alone or in combination. Most lesions shown by SPECT were not shown by CT or MRI in the corresponding anatomical regions. The most severely disabled patients showed the highest number of SPECT lesions (average four per patient) and the lowest (mean, SE) cerebral blood flow (718, 69 ml/min) compared with the less disabled patients (two per patient and 1058, 51 ml/min, p less than 0.05). There was a correlation between the Glasgow Outcome Scale grade and the global cerebral blood flow (r 0.74, p less than 0.05). The perfusion defects may correlate with clinical signs that were not explained by CT or MRI findings. SPECT may complement the clinical evaluation in the assessment of outcome after head injury.

Frequent involvement of the optic radiation in patients with acute isolated optic neuritis

Magnetic resonance imaging revealed asymptomatic lesions in white matter regions corresponding with the optic radiations in 20 of 28 patients (71%) with clinically isolated optic neuritis. In contrast to the findings with symptomatic lesions, there was no relationship between the latency of the visual evoked potential and the presence of these asymptomatic posterior visual pathway lesions.

Cognitive event-related potentials in multiple sclerosis

Twenty-three patients with multiple sclerosis (MS) and 1 patient with isolated optic neuritis (mean age 37.5 yrs, average duration of disease 10 yrs) were tested with auditory and visual cognitive event-related potentials (ERPs) using an oddball paradigm. The results were compared with data from 19 age-matched healthy controls. All patients had magnetic resonance imaging (MRI) head scans and 19 had comprehensive neuropsychological testing. The stimulus-related components of the ERPs were normal for nearly all patients, but 10 showed abnormalities of the later cognitive-related components and another 3 had waveforms in which the cognitive components could not be identified. These abnormalities were found mainly for the auditory test. Of these 13 patients, 11 had significantly prolonged reaction times (RT) or reduced target recognition performance. Five of 8 MS patients with normal IQ and memory function tests had abnormal ERPs with the reverse being true for 4 of 10 patients. Patients with abnormal ERPs showed a higher MRI cerebral lesion score and had a longer duration of illness and greater physical disability than patients with normal ERPs. It is concluded that the generation of ERPs is in part dependent on the integrity of cerebral white matter and that ERPs may indicate subtle degrees of cognitive dysfunction not always detected by standard tests of intellect.

Chronic unilateral optic neuropathy: a magnetic resonance study

We studied the clinical, electrophysiological, and magnetic resonance imaging (MRI) features of 20 patients with chronic unilateral optic neuropathy (CUON): progressive unilateral visual failure lasting a minimum of 6 months. The patients, 10 male and 10 female, ranged in age from 12 to 77 years (mean 44) and had a mean duration of symptoms of 22 months. All had signs of optic nerve dysfunction. Each patient was studied with MRI using a short TI inversion recovery (STIR) sequence to delineate the optic nerve from surrounding orbital tissue. Three distinct groups of patients with CUON were identified using MRI. In the first group (8/20) the optic nerve was compressed by an extrinsic mass, whereas in the second group (5/20) CUON resulted from an intrinsic tumor of the optic nerve or sheath. In both groups STIR sequences compared favorably with computed tomography in identifying mass lesions. MRI was superior in delineating distortion of the optic nerve by mass or tumor extension beyond the orbit. In the third group (7/20) no mass was evident on MRI. However, STIR sequences revealed altered signal (long T1) in clinically symptomatic nerves. In 4 of the patients T2-weighted cerebral MRI disclosed periventricular lesions suggestive of disseminated white matter disease. We conclude that MRI complements clinical and electrophysiological testing in the assessment of CUON.

Cytoskeletal involvement in the sequential capping of rat thymocyte surface glycoproteins

The independent capping of the three major rat thymocyte glycoproteins, the leucocyte-common (L-C) antigen, the leucocyte sialoglycoprotein (LSGP) and Thy-1, was investigated using specific monoclonal antibodies. The capping of each antigen did not require redistribution of the other major surface glycoproteins, and was accompanied by a partial co-capping of the cytoskeletal proteins fodrin and actin, but not of tubulin. A study of the ability of a cell that already possesses one glycoprotein cap to cap a second different glycoprotein showed that this was possible in all cases to varying degrees, the second cap always forming at the same position on the cell surface as the first. Colchicine failed to perturb this observed sequential capping polarity, indicating that microtubules did not direct this second capping event.

Magnetic resonance imaging of the optic nerve in optic neuritis

Magnetic resonance imaging (MRI) of the optic nerves using the STIR (short inversion time inversion recovery) sequence was performed in 37 adult patients with a recent or past attack of optic neuritis. MRI revealed high-signal regions in 84% of symptomatic and 20% of asymptomatic nerves. The mean longitudinal extent of lesions was 1 cm. Slow or poor visual recovery was associated with more extensive lesions, or lesions within the optic canal. Disk swelling was usually associated with anterior lesions but also occurred with lesions in the canal. Visual evoked potentials were even more sensitive than MRI in detecting lesions and are still the investigation of choice in suspected demyelinating disease involving the optic nerve.

A monoclonal alloantibody detecting a polymorphism of the rat leucocyte common (LC) antigen

A monoclonal antibody, NDS 58, was produced by fusing the rat myeloma line Y3 Ag 1.2.3 with spleen cells from AS rats immunized with LEW thymocytes. The determinant recognized by this antibody is leucocyte-specific and present on all thymocytes, lymph node lymphocytes and some bone marrow cells. The strain distribution of NDS 58 was consistent with it being directed at the RT7a allele. Biochemical studies established that this antigen was carried on a cell surface glycoprotein with an apparent molecular weight on thymocytes of 190,000. This study confirms that the alloantigen originally designated Ly-1, and now termed RT7, is an allodeterminant of the LC molecule, and the controversy in this area, particularly with regard to the ART-1 alloantigen, is discussed.

Major histocompatibility complex antigens in the rat pancreas, isolated pancreatic islets, thyroid, and adrenal

Monoclonal antibodies to rat class I and class II MHC antigens have been used with the peroxidase-antiperoxidase technique to localize these antigens in the DA rat pancreas, isolated pancreatic islets, adrenal, and thyroid tissue. The class I (RT1A) antigens were found to be expressed by pancreatic islet cells, adrenal cortical cells, thyroid follicular cells, and--in low concentration--on cells of the adrenal medulla. These same cells did not express class II (Ia or RT1B) antigens. However, interstitial dendritic cells, staining intensely for class II antigens were present in thyroid, adrenal and pancreatic tissue, and within isolated pancreatic islets. These cells probably represent the immunogenic passenger leukocyte.