Changes in paroxysmal brainwave patterns of epileptics by weak-field magnetic stimulation

In order to assess the effects of weak-field magnetic stimulation on brain electrical activity in epileptics, three patients suffering from mesial temporal lobe epilepsy (MTLE) were exposed to DC magnetic fields of 0.9 and 1.8 millitesla (mT). The EEG activity was recorded simultaneously from intracranial electrodes inserted through the foramen ovale (FO) and scalp electrodes. Significant enhancement of interictal epileptiform activity was observed in two patients, while in one patient, magnetic stimulation resulted in the cessation of interictal spike/wave trains.

Recombinant canine alpha-l-fucosidase: expression, purification, and characterization

Canine fucosidosis has proven to be an excellent large animal model both for the equivalent human disorder and, in more general terms, for the central nervous system pathology found in many of the lysosomal storage disorders. Most importantly studies in this animal model were among the first to convincingly show that bone marrow transplantation could successfully modify the course of clinical central nervous system disease and to define some of the important parameters for successful treatment. In order to evaluate other, more generally applicable routes to treatment of central nervous system disease in the lysosomal storage disorders we have expressed recombinant canine alpha-l-fucosidase (rcFUC) in Chinese hamster ovary and Madin-Darby canine kidney cells to levels of between 2 and 13 mg/liter of culture medium and purified the enzyme to apparent homogeneity by affinity chromatography on fucosylamine-linked agarose. rcFUC is composed of subunits of M(r) 50 kDa and the native enzyme is a homotrimer of M(r) 156 kDa. Kinetic properties of rcFUC were similar to those of FUC isolated from both human and dog liver. rcFUC was shown to be effective in correcting the storage phenotype of human fucosidosis cells after endocytosis via the mannose-6-phosphate-receptor-mediated pathway. It was also shown to degrade fucosylated storage products isolated from affected dog brain. The availability of large amounts of rcFUC will allow us to explore ways of extending the proven efficacy of enzyme replacement therapy to the treatment of central nervous system pathology using the fucosidosis dog as a model system.

Malignant catatonia-induced respiratory failure with response to ECT

A 47-year-old acutely psychotic schizophrenic man was diagnosed with malignant catatonia. Because of a history of neuroleptic malignant syndrome (NMS), traditional neuroleptics were avoided, and the patient had been treated with reserpine for a period of 10 years. Symptomatically, severe agitation alternated with severe retardation. The syndrome progressed, despite early termination of any neuroleptic medications, to marked catatonic rigidity and dehydration. Worsening was associated with transfer to a medical intensive care unit, intubation, and subsequently a tracheostomy. Dantrolene and bromocriptine were unhelpful. Lorazepam produced muscular relaxation and resulting decreases in creatine phosphokinase levels but elicited no other improvement. Eleven bilateral electroconvulsive treatments, however, resolved the respiratory impairment and catatonia and improved the psychosis. This report highlights the efficacy of ECT in lethal catatonia despite respiratory impairment and tracheostomy.

Social inequalities and health in rural Chiapas, Mexico: agricultural economy, nutrition, and child health in La Fraylesca region

The objective of this study was to investigate the association between farmers' socioeconomic conditions and their children's health in La Fraylesca, Chiapas. Data were collected using a cross-sectional survey of 1046 households (5546 individuals) sampled from locations in two counties situated in the study area. The survey included anthropometric measurements, a 24-hour dietary recall, stool tests, and childhood mortality data. Children of private farmers and "wealthy peasants" displayed better nutritional status, higher quality diet, lower prevalence of intestinal parasites, and a lower risk of dying than those whose parents were communal farmers, from ejidos, or "poor peasants". The results suggest that using volume of maize production as a classification method proved more valuable than land tenure to identify agricultural groups with different health status. It appears that the main determinants of health differentials are structural inequities in resource distribution. Thus, the impact of medical interventions on inequalities will be limited unless they are accompanied by redistribution of resources.

Nefazodone therapy in patients with treatment-resistant or treatment-intolerant depression and high psychiatric comorbidity

Given the potentially severe functional impairment, morbidity, and high costs associated with refractory depression, it is important to explore all treatment options that may benefit patients with this disorder. This is a retrospective, uncontrolled analysis of our experience with nefazodone therapy in treatment-resistant and treatment-intolerant depression. Potential candidates for nefazodone therapy were referred by their treating psychiatrist. Documentation of failure to respond to previous antidepressant therapy, a diagnosis of clinical depression according to criteria in the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, and completion of a Beck Depression Inventory (BDI) were required before initiation of nefazodone. A follow-up BDI was obtained after > or =4 weeks of nefazodone therapy. A Clinical Global Inventory (CGI) score was obtained retrospectively based on documentation of target symptoms in the clinical record of the last clinic visit. The study group consisted of 20 patients with treatment-resistant or treatment-intolerant major depression who received nefazodone therapy. The mean (+/- SD) age of the group was 48.1+/-9.4 years. The mean number of previously failed antidepressant trials was 1.9+/-0.6. Psychiatric comorbidity in this group was substantial, with posttraumatic stress disorder (PTSD) found in 11 (55%) patients, substance abuse in 3 (15%) patients, and personality disorder found in 2 (10%) patients. After treatment with nefazodone, 11 of 20 patients (55%) were rated on the CGI as much or very much improved. In addition, 9 patients (45%) had >20% improvement on BDI, 3 patients (15%) had 10% to 20% improvement, and 6 patients (30%) had <10% change. Two patients (10%) discontinued nefazodone therapy due to adverse effects. Analysis of our experience with nefazodone therapy in a population with treatment-resistant depression and a high degree of psychiatric comorbidity suggests that approximately 50% of patients may have substantial response to treatment, with a smaller proportion having a more modest clinical response. While receiving nefazodone therapy, most patients continued to take concurrently prescribed psychotropic medications, primarily anxiolytics or other antidepressants. Of interest was the positive drug response among a subgroup of individuals with depression and chronic, severe PTSD. Larger, controlled studies are needed to determine whether these preliminary observations are confirmed.

Receptor mediated binding of two glycosylation forms of N-acetylgalactosamine-4-sulphatase

The lysosomal storage disorders are a group of inherited metabolic diseases each characterised by a relative or absolute deficiency of one or more of the lysosomal proteins involved in the hydrolysis of glycoconjugates or in the transport of the resulting product. Enzyme replacement therapies are under consideration for a number of these disorders and are based on the in vitro observation that cells from affected patients can be corrected by addition of exogenous enzyme. In this study, two glycosylation variants of the lysosomal enzyme N-acetylgalactosamine-4-sulphatase (4S) (the deficiency of which causes Mucopolysaccharidosis (MPS) type VI, (Maroteaux-Lamy syndrome) were made by expression of 4S cDNA in both wild type chinese hamster ovary (CHO-K1), and Lec1 (N-acetylglucosaminyltransferase I deficient CHO-K1) cells. Differences in the glycosylation pattern of the two enzyme forms were demonstrated with endoglycosidase H and N-glycosidase F digestions. The receptor mediated binding of these two forms of 4S to two cell types, human skin fibroblasts and rat alveolar macrophages, was then analysed. We have shown that both enzyme forms bind to the mannose-6-phosphate receptor on human skin fibroblasts with equal affinity demonstrating that the degree of phosphorylation of mannose residues in the two forms is similar. However, using rat alveolar macrophages, we found that the binding/uptake of the two enzymes differs considerably. These results show that differences in glycosylation of lysosomal enzymes can be an important factor in altering enzyme uptake by different cell types. Thus, producing carbohydrate modification variants in this way may be useful for altering the distribution of exogenous enzyme in vivo.

The Repertoire of Social Behaviours of Agile Wallabies, Macropus agilis

The repertoire of social behaviours of the Agile Wallaby, Macropus agilis, was compiled from observations of free-ranging and captive animals in the vicinity of Darwin, Northern Territory. Behaviours were divided into general, maternal, agonistic and sexual contexts. A larger repertoire of behaviours was recorded from captive wallabies but most of these behaviours, except subtle acts like Flehmen and sexual vocalisations, were also seen in free-ranging individuals. The social behaviours of M. agilis are similar to those of other species in the subgenus Prionotemnus. Macropus agilis performed tail-lashing (in sexual, agonistic and general contexts) and males did not use sustained tail support during fights, features which distinguish Prionotemnus from the other subgenera of Macropus. Macropus agilis gave a foot-thump flight signal but also tapped their feet when aware of a potential threat. More complex sexual and agonistic acts which occur in Whiptail Wallabies (Macropus parryi), Euros (Macropus robustus) and Grey Kangaroos (Macropus giganteus) were not observed in M. agilis.

Canine fucosidosis: a model for retroviral gene transfer into haematopoietic stem cells

Severe progressive fatal neurological degeneration occurs in fucosidosis, a storage disease. Bone marrow transplantation into affected dogs has shown that haematopoietic stem cells can provide enzyme producing daughter cells to the central nervous system, altering disease course. This makes canine fucosidosis an ideal large animal model for gene therapy. Fucosidosis affected allogeneic or autologous canine marrow was transduced ex vivo by cocultivation, then transplanted into fucosidosis affected dogs conditioned with total lymphoid irradiation. The vectors were Moloney murine leukaemia virus based. Transduction efficiency was increased with multiple cytokines in short term marrow culture. Despite high levels of transduction, proviral sequence was detected 2 months post transplant in only one dog. Early or total graft failure occurred in all transplants. We believe lack of engraftment could be caused by differentiation or change of repopulating ability of marrow cells occurring with multiple cytokine mixes in culture media.

Neurotrophic immunophilin ligands stimulate structural and functional recovery in neurodegenerative animal models

Although immunosuppressant immunophilin ligands promote neurite outgrowth in vitro, their neurotrophic activities are clearly independent of their immunosuppressive activity. In the present report, a novel nonimmunosuppressive immunophilin ligand, GPI-1046 (3-(3-pyridyl)-1-propyl (2S)-1-(3,3-dimethyl-1,2-dioxopentyl)-2-pyrrolidinecarboxylate+ ++) is described. In vitro, GPI-1046 bound to FK506 binding protein-12 and elicited neurite outgrowth from sensory neuronal cultures with picomolar potency with maximal effects comparable to nerve growth factor. In vivo, GPI-1046 stimulated the regeneration of lesioned sciatic nerve axons and myelin levels. In the central nervous system, GPI-1046 promoted protection and/or sprouting of serotonin-containing nerve fibers in somatosensory cortex following parachloroamphetamine treatment. GPI-1046 also induced regenerative sprouting from spared nigrostriatal dopaminergic neurons following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine toxicity in mice or 6-hydroxydopamine (6-OHDA) toxicity in rats. The rotational abnormality in 6-OHDA treated rats was alleviated by GPI-1046. These neurotrophic actions in multiple models suggest therapeutic utility for GPI-1046 in neurodegenerative diseases.

Isolation and characterisation of a recombinant, precursor form of lysosomal acid alpha-glucosidase

Glycogenosis type II (GSD II, Pompe disease) is an autosomal recessive lysosomal storage disease that results from a deficiency of acid alpha-glucosidase (GAA). Patients with this disorder are unable to break down lysosomal glycogen, which consequently accumulates in the lysosome. To evaluate enzyme replacement therapy for GSD II patients, we have expressed human GAA cDNA in Chinese hamster ovary-K1 cells utilising a vector that places the cDNA under the transcriptional control of the human polypeptide chain elongation factor 1 alpha gene promoter. A clonal cell line that secreted precursor recombinant GAA at approximately 18 mg.l-1.day-1 was identified. The precursor recombinant GAA was purified to homogeneity, had a molecular mass of 110 kDa as measured by SDS/PAGE, and was shown to have pH optima and kinetic parameters similar to those of GAA purified from human tissues. The partial N-terminal amino acid sequence of recombinant GAA conformed to that derived from the nucleotide sequence of the cloned cDNA. The recombinant enzyme was taken up by cultured fibroblasts and skeletal muscle cells from GSD II patients, and was shown to correct the storage phenotype. Endocytosed GAA was localised to the lysosome and showed evidence of intracellular processing to a more mature form. Activity levels increased up to twice the normal value and uptake was prevented if cells were cultured in the presence of mannose 6-phosphate.

Expression, purification and characterization of recombinant human N-acetylgalactosamine-6-sulphatase

Full-length cDNA sequences encoding human N-acetylgalactosamine-6-sulphatase were stably expressed in Chinese hamster ovary cells under the transcriptional control of the human polypeptide chain elongation factor 1 alpha gene promoter. A clonal cell line overexpressing recombinant N-acetylgalactosamine-6-sulphatase to a level of approx. 3 mg/l of culture medium was isolated. The secreted precursor enzyme was purified to homogeneity by a two-column procedure with an overall yield of 53% of the activity. The physical and catalytic parameters of the recombinant enzyme were similar to those of the mature form isolated from liver. On SDS/PAGE and gel filtration, recombinant N-acetylgalactosamine-6-sulphatase had a native molecular mass of 58-60 kDa. Recombinant N-acetylgalactosamine-6-sulphatase was endocytosed by mucopolysaccharidosis IVA fibroblasts via the mannose-6-phosphate receptor-mediated pathway and was efficiently localized to lysosomes.

Spontaneous sustained ventricular tachycardia in the Electrophysiologic Study Versus Electrocardiographic Monitoring (ESVEM) Trial

OBJECTIVES

We compared the QRS waveforms of the initial and subsequent complexes of spontaneous sustained monomorphic ventricular tachycardia and the rhythm induced at electrophysiologic study to test the theory that premature ventricular complexes "trigger" spontaneous ventricular tachycardia and that a stable substrate exists such that the spontaneous arrhythmia can be reproduced at electrophysiologic study.

BACKGROUND

Failure rates have been high in several recent studies in which prevention of ventricular tachyarrhythmias was guided by suppression of premature ventricular complexes or induced ventricular tachycardias.

METHODS

Digital waveform analysis was used to distinguish events of ventricular tachycardia initiated by configurationally distinct, possibly triggering, complexes (type 1) from events in which the initial QRS waveforms were identical to subsequent complexes, suggesting no requirement for premature ventricular beats (type 2).

RESULTS

Of 1,102 episodes of spontaneous ventricular tachycardia, 73 (6.6%) were type 1; 1,012 were type 2 (91.8%); and 17 (1.5%) were uncertain. Of 59 patients only 14 (24%) had only type 1 episodes (group 1), whereas 37 patients (63%) had predominantly type 2 events (group 2) (p < 0.0001). Sustained ventricular tachycardia was inducible in all group 1 patients, and in most (57%) the induced rhythm was similar to the spontaneous rhythm. Ventricular tachycardia could not be induced in 7 patients from group 2 (19%), and in 18 patients (49%) the induced and spontaneous rhythms were dissimilar. Recurrence of arrhythmia rates differed according to the guidance method in group 2.

CONCLUSIONS

Discrepancies between observed and predicted modes of initiation of ventricular tachycardia and between spontaneous and induced rhythms could result in inappropriate guidance and subsequent failure of antiarrhythmic treatment.

Cyclohexylamine inhibits the adhesion of lymphocytic cells to human syncytiotrophoblast

We have previously shown that lymphocytic cells adhere to cultured syncytiotrophoblast and that this may be important in the lymphocyte-mediated infection of trophoblast with the human immunodeficiency virus (HIV). During the course of studies aimed at investigating the role of cell surface carbohydrates in adhesion, it was discovered that a contaminant of commercial fucose-1-phosphate, dicyclohexylamine, inhibited MOLT-trophoblast adhesion. Dicyclohexylamine and the related compounds, cyclohexylamine and hexylamine, inhibited adhesion in a dose-responsive manner with half-maximal inhibition seen at about 4 mM. While the pressor effects of cyclohexylamine, the principal metabolite of cyclamate, are well known, this is the first report of an effect of this and related compounds on cell adhesion activity. The inhibitory effect was reversible and, at concentrations less than 25 mM, did not result in loss of cell viability. Several possible mechanisms of action of cyclohexylamine were examined in an attempt to explain the effect on adhesion. No evidence was found to suggest that the effects of cyclohexylamine were due to inhibition of polyamine synthesis, increase in intracellular Ca2+ concentration or to a lysosomotropic effect. The concentrations of cyclohexylamine used are within the range of plasma concentrations attainable in humans, raising the possibility that the in vitro effects described here may also occur in vivo. The results also suggest that caution should be used in the interpretation of results obtained from experiments where cell adhesion is blocked using exogenous monosaccharides that are in the form of dicyclohexylammonium salts. Appropriate controls must be included or, if possible, sodium, potassium or barium salts should be chosen.

On the sensitivity of the human brain to magnetic fields: evocation of epileptiform activity

Evocation of epileptiform activity by DC magnetic fields of between 0.9 and 1.8 millitesla (mT) has been demonstrated in 6 epileptic patients undergoing presurgical evaluation. The activity was monitored by electroencephalography (EEG) recording from both electrodes attached to the scalp as well as from intracranial electrodes inserted via the foramen ovale. Epileptiform activity evoked by the magnetic field application was distinguished from background levels by comparing the number of epileptiform discharges in the 10-s intervals before and after field applications. In nearly all cases, a delay of up to several seconds was observed between the application of the magnetic field and the onset of epileptiform firing. Removal of the field also appeared to cause firing in some instances, but this has not yet been investigated systematically. In all 6 patients, subsequent seizures confirmed that the epileptiform activity monitored during the experiments was originating from the primary epileptogenic zones of the patients.

Estimating ECG distributions from small numbers of leads

The utility of body surface potential mapping to improve interpretation of electrocardiographic information lies in the presentation of thoracic surface distributions to characterize underlying electrophysiology less ambiguously than that afforded by conventional electrocardiography. Localized cardiac disease or abnormal electrophysiology presents itself electrocardiographically on the body surface in a manner in which pattern plays an important role for identifying or characterizing these abnormalities. Thus, in myocardial infarction, transient myocardial ischemia, Wolff-Parkinson-White syndrome, or ventricular ectopy, observation of electrocardiographic potential patterns, their extrema, and their magnitudes permits localization and quantization of the abnormal activity. Conventional electrocardiography assesses pattern information incompletely and does not use information of distribution extrema locations or magnitudes. Thus, increases or decreases in the magnitudes of electrocardiographic features (ST-segment potential displacement, amplitude, or morphology of Q, R, S, or T waves) associated with changes in cardiac sources (ischemia, infarction, conduction abnormalities, etc.) as measured from fixed leads have a high likelihood of being misinterpreted if the distribution itself is changing. In this study, the authors demonstrate the utility of estimating distributions from small numbers of optimally selected leads, including conventional leads, to reduce uncertainty in the interpretation of electrocardiographic information. This issue is highly relevant when thresholds are used to detect significance of potential levels (exercise testing, detection of myocardial infarction, and continuous monitoring to assess ST-segment changes). Significance of this work lies in improved detection and characterization of abnormal electrophysiology using conventional or enhanced leadsets and methods to estimate thoracic potential distributions.

Magnetic material in the human hippocampus

Magnetic analyses of hippocampal material from deceased normal and epileptic subjects, and from the surgically removed epileptogenic zone of a living patient have been carried out. All had magnetic characteristics similar to those reported for other parts of the brain [6]. These characteristics along with low temperature analysis indicate that the magnetic material is present in a wide range of grain sizes. The low temperature analysis also revealed the presence of magnetite through manifestation of its low temperature transition. The wide range of grain sizes is similar to magnetite produced extracellularly by the GS-15 strain of bacteria and unlike that found in magnetotactic bacteria MV-1, which has a restricted grain size range. Optical microscopy of slices revealed rare 5-10 micron clusters of finer opaque particles, which were demonstrated with Magnetic Force Microscopy to be magnetic. One of these was shown with EDAX to contain AI, Ca, Fe, and K, with approximate weight percentages of 55, 19, 19, and 5, respectively.

Criteria for local myocardial electrical activation: effects of electrogram characteristics

Detection of local electrical myocardial activation by means of extracellular recordings is often difficult in the presence of polyphasic electrograms. The purpose of this investigation was to compare the ability of several variables to distinguish unipolar deflections due to local activation from those due to nonlocal activity. A model of polyphasic deflections based on atrial recordings during reentrant tachycardia was used to facilitate distinction of local and distant activity by methods independent of the test variables. The performance of variables were assessed by comparing areas under receiver operating characteristic curves. Optimal thresholds of test variables were identified by maximizing statistics which corrected for the pretest probability of local activation. We found that the greatest negative first derivative of the unipolar potential discriminated between local and distant ventricular signals, but performed less well than the ratio of the first derivative to the potential for distinguishing between local atrial signals and distant ventricular signals. A linear combination of the potential and the ratio of the first derivative and the potential performed well for all groups of signals studied. We conclude that optimal criteria for detecting local activation depends on the characteristics of the population of signals and that a statistical approach can be used to identify optimal criteria for a given population.

A review of hospitalized patients with bacterial gastroenteritis

The distribution and clinical management of thirty-two hospitalized patients with salmonella and campylobacter infections were reviewed and the impact of these infections on hospital resources was assessed. Eighteen patients with salmonella infection had an age and sex distribution comparable with the community cases. In contrast, 10 out of 14 (71.4%) patients with campylobacter infection were under 20 years of age though the peak incidence of the infection in the community occurred in the 21-65 years age group (67%). There was no male predominance. The median duration of stay in hospital was 6 days for patients with salmonella infection and 3 days for those with campylobacter infection. Physicians were inconsistent in the treatment of campylobacter infection. Overall the financial impact of managing patients with salmonella and campylobacter infection was considerable (1384 pounds and 779 pounds respectively per patient). A limitation on unnecessarily prolonged hospital stays and the establishment of clear guidelines for the clinical management of these infections are necessary.

Determination of local myocardial electrical activation for activation sequence mapping. A statistical approach

Electrical activation sequence mapping requires accurate identification of local activation, but because extracellular recordings do not exclusively reflect local events, complex electrograms may be difficult to interpret. In such cases, the assignment of local activation is subject to error that could affect interpretation of the resulting activation maps. The purpose of this investigation was to develop an approach that would provide quantitative indexes of error in the determination of local activation. An electrode array with 64 closely spaced unipolar electrodes was used to record from the left ventricular surface during open heart surgery. Electrograms with multiple deflections were recorded from four patients with scarred myocardium; two other patients with normal myocardial function served as controls. Each of 784 deflections was scored on the basis of three features: evidence for propagation, the configuration of the bipolar signal, and the effect of changing from the chest to an average reference. Local activation was considered probable if evidence for all three features was present and improbable if none of the three features was present. Deflections that were ambiguous with respect to this standard were excluded. Of over 30 test variables analyzed, the three with the greatest power to discriminate signals due to local activation from those due to distant activity were 1) a linear combination of the extracellular potential plus the ratio of the second derivative and the extracellular potential, 2) the second derivative, and 3) the minimum (greatest negative) first derivative. For each of these variables, the threshold value providing the greatest performance was identified by the maximum quality of efficiency, an index of agreement. This statistical approach provides an objective basis for determining local activation and provides a quantitative assessment of error that could enhance interpretation of electrical activation sequence maps.