Annexin A2, autoimmunity, anxiety and depression.

OBJECTIVES: Antiphospholipid syndrome (APS) is associated with neurological manifestations and one of the novel autoantigens associated with this disease is Annexin A2 (ANXA2). In this work we have examined the effect of high levels of autoantibodies to ANXA2 on the brain in a mouse model. METHODS: Recombinant ANXA2 emulsified in adjuvant was used to immunize mice while mice immunized with adjuvant only served as controls. At peak antibody levels the animal underwent behavioral and cognitive tests and their brains were examined for ANXA2 immunoglobulin G (IgG) and expression of ANXA2 and the closely linked protein p11. RESULTS: Very high levels of anti-ANXA2 antibodies (Abs) were associated with reduced anxiety in the open field 13.14% ± 0.89% of the time in the center compared to 8.64% ± 0.91% observed in the control mice (p < 0.001 by t-test). A forced swim test found significantly less depression manifested by immobility in the ANXA2 group. The changes in behavior were accompanied by a significant reduction in serum corticosteroid levels of ANXA2 group compared to controls. Moreover, higher levels of total IgG and p11 expression were found in ANXA2 group brains. Lower levels of circulating anti-ANXA2 Abs were not associated with behavioral changes. CONCLUSIONS: We have established an animal model with high levels of anti-ANXA2 Abs which induced IgG accumulation in the brain and specific anxiolytic and anti-depressive effects. This model promises to further our understanding of autoimmune disease such as APS and to provide better understanding of the role of the ANXA2-p11 complex in the brain.

Practical experience in the use of mathematical models to predict migration of additives from food-contact polymers.

To reduce the amount of compliance-specific migration testing for food-contact polymers, the use of migration modelling has been evaluated. The paper describes experimental work carried out on a range of plastics and compares measured migrations against predictions obtained using mathematical models. A large number of experimental migration data have been obtained and used to evaluate a Fickian-based migration model in the prediction of specific migration of additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods with test conditions including 2h at 121 degrees C, 6h at 70 degrees C, 2h at 70 degrees C, 2h at 60 degrees C and 10 days at 40 degrees C, representing short-term exposures at high temperatures and room temperature storage. Predicted migrations were calculated by inputting the measured initial concentration of additive in the polymers (Cp,0) into the equations together with known variables such as additive molecular weight, temperature and exposure time. The results indicate the Piringer migration model, using the 'exact' calculations of the Migratest Lite program, predicted migrations into olive oil that were close to or in excess of the experimental results and gave an overestimation for > 95% of the migrations generated here.

Polymer additive migration to foods--a direct comparison of experimental data and values calculated from migration models for high density polyethylene (HDPE).

To reduce the amount of compliance testing for food contact polymers the use of migration modelling has been proposed. This study was conducted to provide valid data for the independent evaluation of two such diffusion-based models using a range of different high density polyethylene (HDPE) polymers and plastics additives. Seventy-two experimental migration data have been obtained in triplicate and used to evaluate two Fickian-based migration models in the prediction of specific migration of four HDPE additives into olive oil. All tests were conducted using olive oil, representing the most severe case for fatty foods with test conditions of 2 h at 70 degrees C, 6 h at 70 degrees C, 10 days at 40 degrees C representing short term exposures at high temperatures and room temperature storage. Predicted migration values were calculated by inserting the measured initial concentration of additive in the polymers (Cp,0) into the equations together with known variables such as additive molecular weight, temperature and exposure time. The results indicate that both models predict migration values into olive oil close to, or in excess of, the experimental results. The Piringer migration model, using the 'exact' calculations of the Migratest Lite program, gave an overestimation for 83% of the migration values generated in this study. The highest overestimation was 3.7 times the measured value. For all measurements, the predicted migration from the Migratest Lite program was greater than 50% of the observed value. The FDA model was found more accurately to predict migration in most situations but underestimated migration more frequently. Differences in the polymer specification had little effect on specific migration of the additives investigated.

Specific migration testing with alternative fatty food simulants.

Many additives used in plastics materials and articles intended for food contact are expected to be assigned specific migration limits (SMLs) in a future amendment to EC Directive 90/128/EEC. In order to demonstrate compliance with these restrictions, specific migration tests will need to be performed on the finished plastics packaging using foods or the appropriate EC food simulants. Owing to the involatile and lipophilic nature of many of these additives, their analysis in the conventional fatty food simulant, olive oil, presents technical difficulties. One way of overcoming these difficulties would be to use a simple solvent alternative to olive oil as has been proposed for overall migration testing. The objective of this work is to compare specific migration data obtained using olive oil with alternative fat simulants iso-octane and 95% ethanol, to find out if similar results are obtained and identify the most appropriate alternative simulant to use for future testing. Good agreement with the olive oil migration data was obtained using 95% ethanol (equivalent exposure conditions) for both of the additives studied in polyolefins. For the polystyrene materials studied it is unlikely that the SMLs for the two additives would be exceeded, and in these cases iso-octane (1.5 h at 60 degrees C) could be used as a rapid 'alternative test'.

Secondary myelodysplastic syndrome following bone marrow transplantation: report of two cases.

We report two cases of secondary myelodysplastic syndrome (SMDS) which followed successful treatment of a primary malignancy with high-dose chemotherapy supported by reinfusion of autologous stem cells. The SMDS was diagnosed 24 months and 40 months, respectively, following autografting. Both patients lived for 7 months after the diagnosis of SMDS. Our cases support the view that there is an increased risk of SMDS/acute leukemia following autologous marrow transplantation.

Activity of twenty-one antimicrobial agents including l-ofloxacin against quinolone-sensitive and -resistant, and methicillin-sensitive and -resistant Staphylococcus aureus.

There is a need to identify alternative agents to vancomycin for the treatment of infections with methicillin-resistant Staphylococcus aureus (MRSA). One candidate is the l isomer of ofloxacin (DR-3355). We tested 520 frozen MRSA isolates, 248 fresh MRSA isolates, and 375 fresh methicillin-susceptible S. aureus (MSSA) isolates from Minnesota, and 600 clinical isolates of S. aureus (150 MRSA and 450 MSSA) from Illinois. Over 90% of the MRSA strains were resistant to 32 micrograms/ml of oxacillin. Of the 520 frozen MRSA, 24% were susceptible to < or = 2 micrograms/ml ofloxacin, and an additional 74% were susceptible to ofloxacin between 8 and 16 micrograms/ml. More than 98% of all strains were susceptible to < or = 16 micrograms/ml ofloxacin or l-ofloxacin. All the quinolones had a bimodal distribution of in vitro activity, but for only ofloxacin and l-ofloxacin was activity confined to a very narrow range.

Evoked metabolic responses in the limbic-striate system produced by stimulation of anterior thalamic nucleus in man.

Six human subjects (5 male, 1 female, age 23.7 + 5.7 years) with incapacitating partial seizure disorders intractable to medical therapy have been treated by ongoing pulsed electrical stimulation of anterior nucleus of the thalamus. Four of the six patients have demonstrated statistically significant clinical control of the seizure disorder. One patient (D.L.) has been seizure-free for the last two years. In two of these six patients, it was possible to study not only electrophysiological activity of the brain, but also regional cerebral glucose metabolism by the (18F) 2-fluoro-2-deoxy-D-glucose method, blood cortisol levels, and blood levels of valproic acid, diphenylhydantoin, and carbamazepine. Significant changes were seen during periods of stimulation compared with control periods without stimulation. These results imply that stimulation of the principal thalamic relay nucleus of the limbic system causes clinical, behavioral, cerebral metabolic, electroencephalographic, endocrinologic, and pharmacokinetic responses.

Chronic cerebellar stimulation (CCS) and deep brain stimulation (DBS) in involuntary movement disorders.

Motor disorders of disinhibition may be modified by prosthetic mobilization of CNS inhibitory mechanisms by chronic electrical stimulation of the cerebellar cortex (CCS) and by deep brain stimulation of the thalamus and internal capsule (DBS). Reduction in spasticity, abnormal movements, intractable epilepsy and aggressive behavior has been reported after CCS, although negative results in human and animal studies have been published. No adverse neurologic, psychologic or intellectual effects of stimulation have occurred after 7 years of CCS, although subclinical histological changes may occur in the cerebellar cortex under the electrodes. CCS has been shown to produce physiological changes in evoked potentials, motoneurone excitability, epileptic discharges in the EEG and quantitative changes in movement. Surface and deep thalamic recordings have shown reduced amplitudes of somatosensory responses after CCS. Over the last 2 years we have employed chronic deep brain stimulation (DBS) in 49 patients with clinically useful results in half the patients. The technique allows reversible modification of movement disorders, and the technique can be used on the second side after a previous thalamectomy. Physiological testing, direct thalamic recordings and quantitative analysis of movement have allowed assessment of optimal rate and voltage of stimulation. For some intractable movement disorders DBS has effected significant therapeutic results when all other therapeutic techniques have failed.

Twenty-five years of experience with physiological neurosurgery.

Twenty-five years of experience with physiological neurosurgery for the treatment of movement disorders leads the author to conclude that such syndromes are caused by disordered mechanisms of sensory communication within the brain. The physiological and therapeutic effects of ablation of the posterior portions of the ventrolateral nucleus of the thalamus, the stimulation of the anterior or rostral cerebellar cortex, and deep brain stimulation of some thalamic nuclei are due to the decrease of pathological disinhibition of motor mechanisms. Further advances in the reversal of chronic neurological symptoms by the alleviation of pathological sensory disinhibition are anticipated.

Reversibility of chronic neurologic deficits. Some effects of electrical stimulation of the thalamus and internal capsule in man.

Stimulation of the thalamus and internal capsule with Medtronic deep brain stimulation electrodes produced improvement in pain, hemiparesis, dystonia, torticollis, tremor. speech impairment and epilepsy. Stimulation at voltages above or below clinically effective levels (e.g., 6 V, 0.3 ms, 74 Hz) resulted in a loss of clinical efficacy. Somatosensory evoked responses (short and long latency) and depth electrode recordings were helpful in localisation and 'biocalibration' of electrical stimulation.

Correlation of clinical and physiological effects of cerebellar stimulation.

The value of clinical assessment of patients undergoing chronic cerebellar stimulation (CCS) is limited by lack of objective measures but neurophysiological tests can be used to "biocalibrate" the stimulator and may be used to predict effects of CCS. Eighty-seven patients undergoing CCS have been assessed clinically and neurophysiologically over the last 4 years. Somatosensory evoked responses were significantly ( p less than 0.05) reduced in amplitude in 35 patients, cortical somatosensory evoked responses in 44 patients and one or both responses were reduced in 55 patients. There were no clinical or physiological changes in 16 patients. Evoked responses showed significant changes in only 3 patients who did not show clinical improvement. The mean voltage settings were 5.2 volts and most patients were stimulated at 200 herz. These results indicate that significant changes in those somatosensory evoked potentials are a good indication of clinical benefits from CCS but clinical improvement may occur in the absence of any acute effect on evoked responses.

Clinical, physiological and philosophical implications of innovative brain surgery in humans.

Abnormal states of motor behaviour can be reversed by interruption of facilitating mechanisms and augmentation of inhibitory mechanisms. Similarly, psychological and emotional behaviours which were abnormal due to disinhibition, such as screaming, repetitive speech and aggressive violent behaviour, have been favourably affected from a clinical and sociological standpoint. The mechanisms of the facilitatory and inhibitory systems which modulate motor behaviour also modify psychological and emotional behaviour. The findings of our studies in experimental neurosurgery may help to provide new insights into mechanisms of mental capacity and behaviour.

Use of chronic cerebellar stimulation for disorders of disinhibition.

A review of the clinical results from 200 patients and the neurophysiological results from 42 patients suggests that chronic cerebellar stimulation (c.c.s.) can improve cerebral palsy and reduce intractable seizures. The therapeutic effects of stimulation of the cerebellar surface may not be due to activation of Purkinje cells. There is evidence that stimulation of brainstem structures, particularly the reticular formation, may be associated with thalamic inhibition; such effects would explain the clinical results of c.c.s. as well as the reduction in amplitude of reflexes, evoked potentials, and paroxysmal discharges in the electroencephalogram. This hypothesis would explain the prolonged, rebound, paradoxical, and cumulative effects of c.c.s. No clinical disturbance or significant tissue damage has resulted from c.c.s. over 5 years. The technique is an example of the therapeutic manipulation of inhibitory and disinhibitory mechanisms in the central nervous system.

Time course of clinical and physiological effects of stimulation of the cerebellar surface in patients with spasticity.

A double-blind study of the short-term (12--48 hours) effects of cerebellar stimulation was performed on 11 selected patients with spasticity. Six of patients had a good clinical long-term response to chronic stimulation, four had a moderate response, and one had no response. Each patient received stimulation for two periods of 24 hours and was off stimulation for two periods of 24 hours. The periods were randomised over four consecutive days. Neither the patients nor the observer could distinguish between the days on stimulation and the days off stimulation. Simple tests of function of the upper limbs during stimulation, measurements of H responses, tonic vibration responses, vibration-induced suppression of H responses, stretch responses, and co-contraction, showed no differences between the four days. These results are contrasted with acute physiological changes seen in some patients during stimulation and also with the slow progressive improvement in clinical function that characterises the successful clinical response. It is suggested that lack of either acute or short-term changes in response to cerebellar stimulation does not predict the clinical outcome. If the strength of stimulation is changed, at least three days and preferably 10 days should be allowed for the effects to appear. The mechanisms responsible for the alleviation of spasticity are likely to be more complex than those mediating acute and reversible changes in reflex activity.

Effects of cerebellar stimulation on epilepsy, the EEG and cerebral palsy in man.

Eighteen of the first 29 patients with intractable epilepsy treated by chronic cerebellar stimulation (CCS) demonstrated a marked suppression of seizures. Sixty-eight of 100 patients with cerebral palsy showed clinical improvement after CCS. Electroencephalographic studies in three epileptic patients revealed a significant (P less than 0.001) reduction in number and duration of paroxysmal EEG discharges during epochs when the stimulator was on; prolonged effects were seen at stimulation rates of 200 c/sec and 10 c/sec (monophasic capacitively coupled stimuli). "Rebound" increases in numbers and durations of paroxysmal discharges occurred after cessation of CCS: immediate "rebounds" occurred within the next 5 min; such rebound effects were also seen in the frequency of clinical seizures. CCS at voltages well above threshold for the production of changes in H reflexes, late motor responses (V1 and V2), and evoked potentials resulted in increased "rebound" effects after cessation of stimulation and such effects were seen clinically and neurophysiologically in epileptic and cerebral palsy patients. Variability in the effects of CCS on seizures and the EEG may have been due to technical factors such as positions and impedances of electrodes, output of the stimulator, effects of anticonvulsant medication and patient differences; there was no clinical or physiological evidence of any undesirable neurological effect of CCS. In one patient, onset of CCS was frequently associated with cessation of polyspike and wave discharges; such results raise the possibility of triggering CCS from paroxysmal discharges in the EEG (contingency feedback) but rebound effects may complicate such therapy.