Free-radical generation by copper ions and hydrogen peroxide. Stimulation by Hepes buffer

Hydroxyl radicals (OH.), generated by a phosphate-buffered Cu2+/H2O2 system, were detected by lucigenin-amplified chemiluminescence, deoxyribose degradation and benzoate hydroxylation. In each system the buffer, Hepes, was found to stimulate radical generation significantly. There are two main reasons for this effect: Hepes increases Cu2+ solubility in phosphate-buffered systems, and forms a complex with Cu2+ that is effective in generating OH. from H2O2. Pipes, a structurally similar buffer, and histidine, a known Cu2+ chelator, were found to have a similar effect. These data suggest that the crucial factor in such free-radical-generating systems is the availability of Cu2+, and that these actions of Hepes should be considered in the design of studies utilizing such systems.

Hydroperoxide-mediated fragmentation of proteins

1. Chemiluminescence and benzoic acid hydroxylation were used to detect oxygen-centred free-radical production by 2.5 mM-H2O2 and 100 microM-Cu2+. Free radicals could not be detected by these methods when H2O2 was replaced with 10 mM-t-butyl hydroperoxide (TBH) or 10 mM-cumene hydroperoxide (CH). The inclusion of the thiol compound dithioerythritol (DTET; 100 microM) increased radical production by H2O2 and Cu2+ as judged by both assays. Mannitol scavenged radicals in the chemiluminescence system in a dose-dependent manner. 2. H2O2, TBH and CH, each with Cu2+, gave rise to substantial fragmentation of the protein bovine serum albumin (BSA). This fragmentation could be increased by the inclusion of DTET. Omission of Cu2+ or the addition of the chelator DETAPAC (diethylenetriaminepenta-acetic acid; 1 mM) lead to virtual abolition of fragmentation. Autoxidized lipid in the presence of Cu2+ caused protein fragmentation by reactions of lipid hydroperoxides. 3. Polyacrylamide-gel electrophoresis in the presence of SDS confirmed that production of fragments had occurred. 4. Susceptibility of BSA to enzymic hydrolysis by two different proteinases acting at pH 5 and pH 7.2 was increased after a limited exposure to hydroperoxides in the presence of Cu2+. 5. These results may have biological significance, particularly for proteins in lipid environments (e.g. membrane proteins and lipoproteins).

Fasciculation and focal loss of nerve accommodation in peripheral neuropathies

Fasciculation of muscle and repetitive response of single motor units to brief electric stimuli in diffuse demyelinative and focal (compression) neuropathies are associated with localised loss of accommodation of motor nerve fibres. The pathogenesis of spontaneous and triggered repetitive firing of neurones is discussed and it is proposed that the discrete sites of abnormally low accommodation may be in regenerating (sprouting) neurones. An improved rapid method for measuring single fibre accommodation may be used to identify regenerating neurones.

Local sites of low accommodation of peripheral motor axons and the pathogenesis of fasciculation in amyotrophic lateral sclerosis

There is no generalized disturbance of accommodation of peripheral motor axons in amyotrophic lateral sclerosis. Local sites of reduced accommodation are found proximally and distally with apparent correlation to spontaneous fasciculation. The possible mechanism of fasciculation provoked by acetylcholine is discussed and it is suggested that the local sites of low accommodation represent nodal sprouts with growth cones in extra-muscular as well as intra-muscular parts of peripheral motor axons.

An improved method for rapid measurement of accommodation and firing frequency of single motor units in man

A stimulator is described producing trapezoid wave forms with accurately defined linear rise and fall at pre-determined slopes independent of the maximum current which is limited at the threshold for a motor unit recorded by discriminative electrodes. The stimulation threshold, measured in rheobase units, is directly proportional to the latency of response and is more accurately measured by sweep expansion (by computer). Thresholds to linearly rising currents of pre-selected slopes are rapidly measured and plotted on a grid calibrated to allow immediate measurement of the time-constant of accommodation.

Alginate inhibition of the uptake of Pseudomonas aeruginosa by macrophages

Pseudomonas aeruginosa alginate was purified and characterized in terms of uronic acid, carbohydrate and protein content, as well as by infra-red spectroscopy and gel electrophoresis. Added exogenous bacterial alginate inhibited the uptake and degradation of both viable and non-viable radiolabelled non-mucoid P. aeruginosa by resident mouse peritoneal macrophages. Alginic acid (from seaweed) inhibited the same parameters to almost the same degree. Bacterial alginate also inhibited the uptake of fluorescent-labelled zymosan and latex particles. Starch, at equivalent viscosity to the alginate, inhibited the uptake and degradation of radiolabelled nonviable P. aeruginosa to a greater extent, but Dextran T500 had no effect. This suggests that the viscous nature of alginate exerts a non-specific inhibitory effect on the uptake and subsequent degradation of phagocytosible particles.

Abetalipoproteinaemia in adults: role of vitamin therapy

The retinal and neurological complications of abetalipoproteinaemia may be preventable by replacing vitamins A and E from an early age, but their role in adult presentations is less clear. Two adult females with abetalipoproteinaemia have received 8 and 10 years respectively of replacement therapy with vitamins A, E and linoleic acid. In Case 1, visual function improved objectively on commencing therapy but has subsequently deteriorated and her neuropathy has slowly progressed. The rate of progression of neurological impairment in Case 2 was slowed but not halted by therapy, and her severe visual disturbance was unaffected. Replacement by fat soluble vitamins has only a limited role in the management of abetalipoproteinaemia once irreversible neurological/retinal damage has occurred.

Aggressive thyroid cancer in low-risk age population

Seventy-eight patients under the age of 40 (low-risk patients) who had undergone surgical treatment for well-differentiated thyroid carcinoma were referred from 1979 to 1986 to our hospital for adjuvant therapy. A subgroup of 37 patients, 14 with apparent aggressive cancer, was studied. This study group consisted of 27 female and 10 male patients with mixed papillary and follicular cancer, who ranged in age from 11 to 40 years. Nodal disease occurred in 27 (73%) patients and invasiveness in 30 (81%) patients and involved multiple areas in 9 (24%) patients. Recurrence occurred in 14 (38%) patients and visceral metastases occurred in eight (22%) patients. All patients underwent appropriate surgery, but microscopic residual disease was seen in 15 patients and gross residual disease in seven patients, so that 31 patients underwent iodine-131 therapy, and 17 of these patients also underwent external radiation therapy. Three patients died of their disease, whereas 24 (65%) patients are free of disease and 9 (24%) patients are alive with disease. An additional 7 (19%) patients were initially seen in the fifth to seventh decade after decades of neglected thyroid disease, which culminated in residual cancer and death. Although low-risk categorization for thyroid cancer appears valid, its rigid application in support of conservative treatment may lead to inadequate primary treatment and underdiagnosis of cancer in thyroid nodule disease in the low-risk age population.

Readiness potential of cortical area 6 preceding self paced movement in Parkinson's disease

The vertex Readiness Potential (RP) (Bereitschaftspotential) preceding self paced voluntary movements is reduced in duration and amplitude in patients with Parkinsonism. It cannot be used as an index for delayed initiation of movement. The negative potential is commonly replaced by a positive slow wave. In hemi-Parkinsonism, the abnormal RP is more apparent on moving the affected limb. The abnormal RP is related to the severity but not to the duration of Parkinsonism. Short-term fluctuations of akinesia and rigidity, spontaneous or caused by levodopa are associated with changes of RP duration and amplitude. The abnormality does not correlate with reaction or movement times. It is suggested that the Readiness Potential is a diffuse response of area 6 cortex (especially Supplementary Motor Area) evoked by pallido-thalamo-cortical afferents under dopaminergic control. It is not obligatory for pre-programming of voluntary movement. The authors postulate a dendritic potential of basket cells associated with a pallidal activated gate control of postural set.

Treatment of myasthenia gravis: an audit

Although treatment of myasthenia gravis with anticholinesterase drugs and thymectomy was based on wrong models of pathogenesis the resulting saving of life has not been improved by immunosuppressive treatment based on a current autoimmune model. Immunosuppression with steroids or azathioprine may reduce morbidity but as these drugs can rarely be withdrawn without causing relapse, the long-term hazards are serious, including increased mortality.

Beta-lactamase-producing isolates of Neisseria gonorrhoeae in Cape Town

Isolates of Neisseria gonorrhoeae from patients attending the sexually transmitted disease clinics of the Cape Town Municipal Health Department were examined for beta-lactamase (penicillinase) production by a chromogenic cephalosporin test. Of the 208 isolates, 4 (less than 2%) produced beta-lactamase. When grown on chocolate blood agar plates 3 isolates showed no inhibition of growth around a penicillin disc; the 4th had a markedly reduced zone of inhibition. The minimum inhibitory concentrations of penicillin for these 4 strains were from 1 to 4 micrograms/ml.

High-dose radiation and the emergence of thyroid nodular disease

High-dose radiation (in excess of 2500 rads or centiGray) to the head and neck area is reputedly infrequently associated with the emergence of thyroid nodular disease. Thirty-three patients who underwent high-dose radiation and who developed thyroid nodular disease have been described. Radiation was originally administered for hyperthyroidism in 11 patients, postmastectomy in five, oral cancer in three, Hodgkin's disease in three, facial hirsutism in three, hemangioma in three, cancer of the larynx in one, skin cancer in one, desmoid tumor of the neck in one, Ewing's tumor in one, and pituitary tumor in one. Treatment included radioiodine in 11, external radiation in 21, interstitial radiation in one, and combined radiation in one. Associated head and neck neoplasms included four parathyroid tumors, one osteogenic sarcoma of the maxilla, two basal cell cancers of the facial skin, and one parotid gland carcinoma. The study group consisted of five men and 26 women varying in age from 22 to 75 years, with a duration of latency of effect varying from 1.5 to 50 years. Thyroid disease consisted of 21 cancers, six adenomas, four colloid goiters, and two cases of thyroiditis resulting in four deaths caused by cancer, for a 20% mortality rate. Consideration of radiation beam behavior showed that isodose curve, penumbra effect, back scatter, and special field resulted in the thyroid gland receiving a low dose, namely under 2500 rads. Clinical factors such as an overlooked goiter, coincidental carcinoma, error in presumption of dose, and second primary malignancy were also considerations. True biologic radiation oncogenesis may have been seen in our radioiodine-treated group with hyperthyroidism as well as the group with Hodgkin's disease who underwent mantle irradiation. It is apparent that for whatever reason and by whatever means and by whatever mechanism, high-dose radiation to the head and neck area can result in significant thyroid disease, and patients undergoing such radiation should be followed with this in mind and considered for thyroid feeding on a prophylactic basis.

alpha-Bungarotoxin displacing antibody in myasthenia gravis

The majority of sera from myasthenic patients cannot precipitate all available receptor-toxin complex even in conditions of a 4,000-fold excess of antibody. This effect was traced to displacement of toxin from the receptor-toxin complex. Pure IgG prepared from the serum of a myasthenic patient was as effective as the original serum in displacing ability. The possible effect of such antibodies on the correlation of antibody titre and disease state is discussed.

alpha-Bungarotoxin binding to the nicotinic acetylcholine receptor is inhibited by two distinct subpopulations of anti-receptor antibodies

Affinity-purified antibodies to the nicotinic acetylcholine receptor of Torpedo marmorata were fractionated into two populations using a covalently cross-linked receptor-toxin immunosorbent lacking free toxin-binding sites. The population of antibodies which bound to and were subsequently eluted from this resin, and which cannot possibly contain antibodies directed to the toxin-binding site itself, was effective in inhibiting the binding of toxin to receptor in solution. This unequivocally demonstrates that inhibition of toxin binding can be mediated by antibodies which are not directed against the toxin-binding site. A second minor population of antibodies which did not bind to the affinity resin but which did inhibit the binding of toxin to receptor in solution was detected. Two subpopulations of toxin-binding inhibitory antibodies can therefore be distinguished. A clear differentiation should be made in future work describing "anti-toxin site" antibodies between antibodies directly binding to the toxin-binding site and the pseudo-anti-toxin-binding site antibodies described in this report.

The myasthenic (Eaton-Lambert) syndrome associated with carcinoma. Enzyme induction as a possible mechanism of paraneoplastic syndromes

A myasthenic syndrome associated with small-cell tumours of the bronchus and with autoimmune diseases (Eaton-Lambert syndrome) has been attributed to diminished probability that a nerve action potential will release acetylcholine (ACh) from terminals of cholinergic nerves (somatic motor and autonomic). This model derives from evidence for reduced quantal content of the transmitter released by a nerve impulse. The test procedure implies certain constancies of postsynaptic response. Abnormal responses to ACh-agonists indicate that receptor response is not normal. It is suggested that all previously described neuromuscular responses are compatible with new model: the subsynaptic apparatus produces excess acetylcholinesterase (AChE) which limits the endplate conductance changes produced by normal output of ACh. This model is supported by earlier ultramicroscopic studies which cannot be accounted for by the contemporary model. It is proposed that enzyme induction by peptide or immunoglobulin may also be responsible for other paraneoplastic syndromes.

Experimental myasthenia gravis is inhibited by receptor-antireceptor complexes

Experimental autoimmune myasthenia gravis (EAMG) induced in rabbits by immunisation with purified nicotinic acetylcholine receptor from Torpedo marmorata is a highly reproducible model for the human disease. Pretreatment of experimental animals with immune complexes containing receptor and anti-receptor antibodies suppressed the subsequent induction of EAMG. Animals were protected from the normal severe paralysis. Moreover, antibody levels were reduced by synthesis of antibody rapidly terminated. Possible mechanisms are discussed.

Lack of inter-animal cross-reaction of anti-acetylcholine receptor antibodies at the receptor-binding site as demonstrated by heterologous anti-idiotype antisera: implications for immunotherapy of myasthenia gravis

Anti-idiotype antisera were raised in rabbits by immunization with purified sheep anti-Torpedo receptor antibodies. The antisera were able specifically to block the binding of receptor to the inducing antibodies but not anti-Torpedo antibodies from other animals of the same, or other, species. Rabbits producing the anti-idiotype sera were not protected from experimental autoimmune myasthenia gravis (EAMG). The implications of these observations for the potential use of anti-idiotype antisera in the treatment of myasthenia gravis are discussed.

Anti-acetylcholine receptor antibody titres in the sera of myasthenia patients treated with plasma exchange combined with immunosuppressive therapy

Anti-acetylcholine receptor antibody titres have been monitored in the sera of 19 myasthenic patients treated with plasma exchange combined with a three month period of immunosuppressive therapy. In general the post-exchange titres stabilised at below pre-exchange levels for prolonged periods which were associated with clinical improvement. In seven instances recurrence of symptoms occurred and in six of these cases relapse was shown to be associated with a rise in anti-acetylcholine receptor antibody titre.

Saturnian Trapped Radiation and Its Absorption by Satellites and Rings: The First Results from Pioneer 11

Electrons and protons accelerated and trapped in a Saturnian magnetic field have been found by the University of Chicago experiments on Pioneer 11 within 20 Saturn radii (Rs) of the planet. In the innermost regions, strong absorption effects due to satellites and ring material were observed, and from approximately 4 Rs inwards to the outer edge of the A ring at 2.30 Rs (where the radiation is absorbed), the intensity distributions of protons (>/= 0.5 million electron volts) and electrons (2 to 20 million electron volts) were axially symmetric, consistent with a centered dipole aligned with the planetary rotation axis. The maximum fluxes observed for protons (> 35 million electron volts and for electrons < 3.4 million electron volts) were 3 x 10(4) and 3 x 10(6) per square centimeter per second, respectively. Absorption of radiation by Mimas provides a means of estimating the radial diffusion coefficient for charged particle transport. However, the rapid flux increases observed between absorption features raise new questions concerning the physics of charged particle transport and acceleration. An absorption feature near 2.5 Rs has led to the discovery of a previously unknown satellite with a diameter of approximately 200 kilometers, semimajor axis of 2.51 Rs, and eccentricity of 0.013. Radiation absorption features that suggest a nonuniform distribution of matter around Saturn have also been found from 2.34 to 2.36 Rs, near the position of the F ring discovered by the Pioneer imaging experiment. Beneath the A, B, and C rings we continued to observe a low flux of high-energy electrons. We conclude that the inner Saturn magnetosphere, because of its near-axial symmetry and the many discrete radiation absorption regions, offers a unique opportunity to study the acceleration and transport of charged particles in a planetary magnetic field.

Plasma-exchange combined with immunosuppressive therapy in myasthenia gravis

Twenty-one patients with myasthenia gravis underwent a course of plasma exchange combined with immunosuppressive therapy. In fifteen there was dramatic clinical improvement which has been maintained for periods up to 19 months. Nine of these patients now take no anticholinesterase drugs. Six patients had a recurrence 3--9 months after the first course but in the three given a second course remissions were again obtained.

Solanum torvum as a causative agent of enzootic calcinosis in Papua, New Guinea

Inclusion of dried powdered leaves of Solanum torvum Swartz (collected in Papua, New Guinea) in the diet of rats induced hypercalcaemai rapidly and hyperphosphataemia more slowly; soft tissue calcification was most evident in the kidney and lung. Solanum torvum may be a causative agent of enzootic calcinosis in cattle in Papua, New Guinea.

The place of surgery in the treatment of myasthenia gravis

The clinical conditions, operative and postoperative management of 64 pateints submitted to thymectomy from 1965 to 1976 have been reviewed retrospectively. The results of 11 thymectomeis done before 1965 have been previously reported (Fraser, 1966). We consider that the duration of illness is a more important criterion than the age or sex of the patient or the distribution of weakness, and we recognize three stages (Simpson, 1974). Stage I, the active stage, is characterized by remissions and best response to thymectomy. it normally lasts for 5-7 years and is followed by stage 2, the inactive stage. In stage 2 there is less risk of death but few spontaneous reminssions and less response to thymectomy. In stage 3, the burned-out stage, there may be steady improvement but thymectomy is without benefit and responsiveness to anticholinergic drugs becomes less.

It has been our policy to perform thymectomy as early as possible in stage 1. In addition, stage 2 patients have been advised operation if the response to anticholinesterase medication has been unsatisfactory, Although major improvement is not anticipated until 2-3 years after operation, we have felt justified in offering thymectomy because we have had no death as a direct result of the actual operative procedure. One patient died suddenly and unexpectedly on the tenth day postoperatively (1.7 per cent). At follow-up there were 6 late deaths. Of the 52 patients available for review, 92.3 per cent had no symptoms or only mild disability.

Myasthenia gravis: a personal view of pathogenesis and mechanism, part 2

A review of our current knowledge of the etiology and pathogenesis of myasthenia gravis is presented, with particular emphasis on the immunological aspects of the disease. Part 1, published in the January/February issue of MUSCLE & NERVE, dealt with the clinical and genetic features of myasthenia gravis which led to the autoimmune theory of the etiology of the disease. Part 2, which appears in this issue, provides a review of the dysfunction of physiology, pharmacology, and structure of the neuromuscular junction in myasthenia gravis, and the part played by the autoimmune process.

Myasthenia gravis: a personal view of pathogenesis and mechanism, part 1

A review of our current knowledge of the etiology and pathogenesis of myasthenia gravis is presented, with particular emphasis on the immunological aspects of the disease. Part 1, published in this issue, deals with the clinical and genetic features of myasthenia gravis which led to the autoimmune theory of the etiology of this disease. Various theories in this field are reviewed, and recent advances in our knowledge of the acetylcholine receptor protein, and its immunology, are examined. Part 2, which will appear in the March/April issue, provides a review of the dysfunction of physiology, pharmacology, and structure of the neuromuscular junction in myasthenia gravis, and the part played by the autoimmune process.

Penicillamine-associated myasthenia gravis, antiacetylcholine receptor and antistriational antibodies

Myasthenia gravis with thymic hyperplasia developed in a patient with Wilson's disease after eight years of penicillamine treatment. Four months prior to the onset of myasthenia, penicillin hypersensitivity was observed. Immunofluorescence on the excised thymus revealed immunoglobulin and complement deposition, but the myasthenia persisted after thymectomy and continuation of penicillamine therapy. Increased antiacetylcholine receptor antibody was demonstrable throughout. This patient subsequently became pregnant, enabling studies to be performed on the transplacental transfer of the immunoglobulin G (IgG) class antiacetylcholine receptor antibody. Eleven cases of rheumatoid arthritis with penicillamine-associated antistriational antibodies have also been observed; in three of these cases there was evidence of myasthenia gravis. These observations extend earlier reports of the association of penicillamine with myasthenia gravis and suggest that antistriational antibody, antiacetylcholine receptor antibody and thymic hyperplasia may be independent effects of penicillamine therapy.

Studies on the nature of autoimmunity in myasthenia gravis. Evidence for an immunodeficiency type

Clinical and laboratory data continue to support the concept of a genetically determined breakdown of immunological tolerance in myasthenia gravis with immunological damage to the motor end plates. The demonstration of impaired function of thymus-derived lymphocytes and of IgA deficiency correlate well with the clinical data in which there is an increase incidence of autoimmune diseases associated with anergy. Whilst the exact pathogenesis of myasthenia gravis is unknown, the available data support the concept of an immune deficiency disorder.

Pulmonary resection for localized lesions of cryptococcosis (torulosis): a review of eight cases

Torulosis is an uncommon, but potentially lethal disease. The aim of this report is to indicate that resection of isolated pulmonary lesions due to torulosis is a safe procedure. Resection has proved useful in the definitive diagnosis and treatment of eight cases seen in this thoracic surgical unit.

Absence of cellular hypersensitivity to muscle and thymic antigens in myasthenia gravis

Humoral antibodies to skeletal muscle and its components and to thymus have been demonstrated in the sera of patients with myasthenia gravis. A role for cellular hypersensitivity to similar antigens in the pathogenesis of the disease has been suggested by some reports of the presence of cellular immunity. A detailed immunological study using muscle and thymic antigens, including those prepared from the patients' own tissues, failed to confirm these findings. It is suggested that previous reports of cellular hypersensitivity represent the demonstration of an epiphenomenon.

Jupiter Revisited: First Results from the University of Chicago Charged Particle Experiment on Pioneer 11

During the December 1974 Pioneer 11 Jupiter encounter our experiment provided measurements of Jovian energetic protons and electrons both in the magnetic equatorial zone and at previously unexplored high magnetic latitudes. Many of the observations and conclusions from the Pioneer 10 encounter in 1973 were confirmed, with several important exceptions and new findings. We report evidence from Pioneer 11 for protons ( approximately 1 million electron volts) of Jovian origin in interplanetary space. In the outer magnetosphere particle intensities at high magnetic latitudes were comparable to those observed in the equatorial zone, and 10-hour variations in particle intensities and spectra were observed at both high and low magnetic latitudes. Therefore, confinement of particles in the outer magnetosphere to a thin equatorial magnetodisc is adequate neither as a description of the particle distribution nor as a complete explanation of the 10-hour variations. Pioneer 11 data support a model in which the intensity varies with a 10-hour period in phase throughout the sunward side of the magnetosphere and is relatively independent of position within the magnetosphere. Transient, highly anisotropic bursts of protons with energies of approximately 1 million electron volts observed near the orbit of Ganymede suggest local acceleration in some regions of the magnetosphere. In the inner core where particles are stably trapped, a maximum in the high-energy nucleonic flux was again found, corresponding to the Pioneer 10 maximum at approximately 3.4 Jupiter radii (R(J)), which is apparently a persistent feature of, the inner radiation zone. In addition, Pioneer 11 data indicate two more local maxima in the nucleonic flux inside 3.4 R(J), one of which may be associated with absorption by Amalthea, and a maximum intensity at 1.9 R(J) more than 20 times that at 3.4 R(J), The flux of relativistic electrons reached a maximum on the magnetic equator at 1.8 R(J), only slightly less its closest approach at 3.1 R(J).

Comparison of thymic histology with response to thymectomy in myasthenia gravis

Fifty-four thymus glands removed surgically from patients with myasthenia gravis were examined using an accurate morphometric technique and the data compared with the response to thymectomy. There is a tendency for patients with relatively unreactive thymus glands to obtain a better result from thymectomy but this is not statistically significant.

Search by Mariner 10 for Electrons and Protons Accelerated in Association with Venus

The University of Chicago instrumnents on board the Mariner 10 spacecraft bound for Mercury have measured energy spectra and fluxes of electrons from 0.18 to 30 million electron volts and protons from 0.5 to 68 million electron volts along the plasma wake and in the bow shock regions associated with Venus. Unusually quiet solar conditions and improved instrumentation made it possible to search for much lower fluxes of protons and electrons in similar energy regions as compared to earlier Mariner missions to Venus-that is, lower by a factor of 10(2) for protons and 10(3) for electrons. We found no evidence for electrons or protons either in the form of increases of intensity or energy spectral changes in the vicinity of the planet, nor any evidence of bursts of radiation in or near the observed bow shock where bursts of electrons might have been expected in analogy with the bow shock at the earth. The importance of these null results for determining the necessary and sufficient conditions for particle acceleration is discussed with respect to magnetometer evidence that Venus does not have a magnetosphere.

Protons and Electrons in Jupiter's Magnetic Field: Results from the University of Chicago Experiment on Pioneer 10

Fluxes of high energy electrons and protons are found to be highly concentrated near the magnetic equatorial plane from distances of ~ 30 to ~ 100 Jovian radii (R(J)). The 10-hour period of planetary rotation is observed as an intensity variation, which indicates that the equatorial zone of high particle fluxes is inclined with respect to the rotation axis of the planet. At radial distances [unknown] 20 R(J) the synchrotron-radiation-producing electrons with energies greater, similar 3 million electron volts rise steeply to a maximum intensity of ~ 5 x 10(8) electrons per square centimeter per second near the periapsis at 2.8 R(J). The flux of protons with energies greater, similar 30 million electron volts reaches a maximum intensity of ~ 4 x 10(6) protons per square centimeter per second at ~ 3.5 R(J) with the intensity decreasing inside this radial distance. Only for radial distances [unknown] 20 R(J) does the radiation behave in a manner which is similar to that at the earth. Burst of electrons with energies up to 30 million electron volts, each lasting about 2 days, were observed in interplanetary space beginning approximately 1 month before encounter. This radiation appears to have escaped from the Jovian bow shock or magnetosphere.