Aseptic necrosis and glucocorticosteroids in systemic lupus erythematosus: a reevaluation

To reassess predisposing factors in patients with systemic lupus erythematosus (SLE) who develop aseptic necrosis of bone, we studied 172 patients with SLE seen at our institution between 1975 and 1987 followed for longer than 1 year. Twenty-eight (16.3%) of these patients developed clinically apparent aseptic necrosis. In 12 of these 28 the continuous glucocorticosteroid dose was known. These 12 patients were compared to 15 controls with SLE followed for a minimum of 4.5 years for whom continuous glucocorticosteroid dosage was also known. We were unable to find any significant differences between patients with aseptic necrosis and controls in prevalence of specific lupus organ system involvement, Raynaud's phenomenon, or abnormal serological or hematological variables. Overall disease activity at the time of maximal glucocorticosteroid dosage did not differ significantly between the 2 groups but was slightly greater at the time SLE was diagnosed in the group with aseptic necrosis. Glucocorticosteroid intake during the first 1.5 years after diagnosis of SLE and during the third year after diagnosis was significantly greater for the patients with aseptic necrosis than for the control patients, as was glucocorticosteroid intake during the maximal 1, 3 and 6 months of therapy. We conclude that glucocorticosteroid intake is the major factor predisposing to aseptic necrosis in patients with SLE.

Outcome of an osteoarthritis education program for low-literacy patients taught by indigenous instructors

A 10-h osteoarthritis education course was developed and evaluated for older low-income patients with osteoarthritis. Indigenous community leaders were trained to teach the course within inner-city neighborhoods of Hartford, Connecticut. Significant differences were obtained using a quasi-experimental group, pre/post-test design. There was a significant increase in knowledge (P less than 0.001) both on a verbal knowledge test and a picture story test (P less than 0.001). There was a significant increase in scores on an exercise scale (P less than 0.001). Attitude toward one's illness improved. There was a slight improvement in function which was not significant. Use of adaptive equipment increased as a direct result of the program. The course was well accepted and enjoyed by the participants.

Single unit activity in the auditory cortex of a monkey performing a short term memory task

Short term memory to tones (STMT) was investigated by recording single unit activity in the auditory cortex of a behaving monkey. The activity of each unit was studied in two behavioral conditions: a) During task performance, the monkey had to compare two tones separated by one second of silence (inter-stimulus interval). b) During a non-performing period; the monkey heard the two tones but did not respond behaviorally. It was noted that the firing rate of many units during the inter-stimulus interval (ISI) was dependent on the frequency of the first tone. Such dependency was observed even towards the end of the ISI, both during task performance trials (50% of the units) and during the non-performing period (32% of the units). The activity of these units could be the basis of STMT in both of these behavioral states. In 65% of all the units tested, the responses during the ISI were of a higher magnitude in the performance period than were the responses in the non-performance period. The activity of these units may be related either to general processes such as attention and expectation or to short-term memory processes. During task performance, the responses of 23% of the units to the second tone were dependent on whether its frequency was identical to that of the first tone. Such dependency was never observed during the non-performing period. These units may detect similarity or non similarity between two tones presented one second apart. Periodic patterns of firing were not found in the study, thus suggesting that the ISI responses were not generated by reverberatory activity in simple closed loops. On the basis of these results, several alternative mechanisms of STMT are suggested.

Sacroiliitis and brucellosis

A 21-year-old Peruvian man presented with sacroiliitis, fever, elevated liver enzymes, abdominal and right scrotal pain. Brucellosis was diagnosed based on culture and serological data. Appropriate therapy led to full recovery. Our case presents a timely reminder that brucellosis should always be considered as part of the differential diagnosis of sacroiliitis.

Neuronal activities related to higher brain functions--theoretical and experimental implications

The activities of several single units (6-10) were recorded simultaneously in the auditory cortex and in frontal cortical areas of cats and monkeys. The response properties of the single units and the interaction between them were studied. It is shown that single units in both areas may participate in prolonged processes and be involved in more than one process. Adjacent neurons need not function in unison; while some neurons are activated, others may stay inactive. The interactions among adjacent neurons are weak, and can be modulated by sensory stimulation, and by arousal and behavioral states. These properties lead us to hypothesize that information is represented in the cortex by coactivation of sets of neurons rather than by independent modulation of the single-unit firing rate. A single unit may be a member of several representing sets. Thus, each neuron may participate in more than one function and each small cortical area may contain members of several functional sets. A mechanism for computing and transmitting information, based on converging-diverging links, between neuronal sets is described and tested by simulations and analysis of experimental data.

Detecting spatiotemporal firing patterns among simultaneously recorded single neurons

1. A particular firing pattern among simultaneously observed neurons represents a particular sequence of activity. If any multineuron pattern repeats significantly more than expected by chance, we may be observing a repeated state of a neural assembly as it processes similar units of information. 2. We present here an algorithm that rapidly finds all single or multineuron patterns that repeat two or more times within a block of data, as well as equations for calculating the number of patterns of given length and repetition that would be expected. The complexity of patterns for which it is practical to compute expected numbers is three to six spikes (inclusive). 3. Confidence limits are based on these expected numbers of patterns, so that is possible to identify groups of patterns that are worthy of further analysis. 4. These methods are tested against simulated multineuron data that has various types of known nonstationarities, with good agreement between observed and expected values. 5. Application to real spike trains shows a large excess of observed repeating patterns, of which some, but not all, are shown to be due to bursts of high frequency firing. 6. It should be possible to apply the new method as a filter in real time in order to search for an association between repeated pattern events and externally observable events (stimulus, behavior, etc.). Any repeated pattern events which cannot be so associated may represent a new indicator of internal events in the nervous system.

Polymyositis with tubular aggregates

We report a patient with classic idiopathic polymyositis who had tubular aggregates on muscle biopsy. Tubular aggregates are distinctly rare in polymyositis although seen in a variety of other muscle disorders including myopathies associated with muscle cramping. Our patient did not have muscle cramps or severe myalgia. Moreover, the patient's disease responded to steroids, indicating that tubular aggregates were not a marker for steroid resistance. The function of the tubular aggregates in this disease is not clear.

Computer-based patient education for older persons with osteoarthritis

A program of 8 lessons on various aspects of osteoarthritis (OA), its treatment, and patient self-care was prepared on an Apple IIc computer. The courses were then field-tested and evaluated by 72 older (age range 52-88) OA patients in community centers for senior citizens. Statistical analysis of the findings showed significant increases in knowledge and significant self-reported, beneficial behavior changes, including increased exercise, use of heat, and rest. Our findings demonstrate that older persons can use the computer to learn to cope with OA when a thoughtfully planned program is made available in a community setting.

Temporal firing patterns of single units, pairs and triplets of units in the auditory cortex

The spontaneous and acoustically driven activities of single units, pairs and triplets of units in the auditory cortex were analyzed. Data were obtained in two sets of experiments from nonbehaving awake cats and from a behaving monkey. The results of the two sets of experiments indicated that neighboring neurons usually fire independently. The weak correlations found between pairs of adjacent neurons were mostly indicative of a common input driving both units. In some cases, signs of synaptic interaction between the neurons were found. When triplets of units were considered, it was found that several independent inputs exist, even within a small group of adjacent neurons. When such small groups of neurons were studied in the behaving monkey, it was found that the temporal firing pattern of single neurons and the interactions between pairs of neurons were in some cases dependent on the behavioral state and on the sensorimotor association.

Dermatomyositis and Hodgkin's disease. Case report and review of the literature

The association between dermatomyositis and Hodgkin's disease has been infrequently reported. A patient with advanced Hodgkin's disease and dermatomyositis is presented and an additional 11 cases obtained from the world literature are reviewed. The clinical features, response to treatment, and outcome of these diseases are discussed.

Sartorial ridge gout

A 54-year-old man presented with acute swelling and pain in the posteromedial aspect of the knee not involving the joint itself. Aspiration of the soft tissue swelling produced viscous fluid in which multiple, negatively birefringent crystals were noted on compensated polarized microscopy. The first described case of acute gout involving the sartorial ridge, this case underlines the need for examining aspirated fluid from soft tissue as well as from joints for crystals.

The effects of stimuli on the activity and functional connectivity of local neuronal groups in the cat auditory cortex

Simultaneous extracellular recordings from one electrode of 'local' groups of 3-6 neurons were obtained from the auditory cortex of unanesthetized, paralyzed cats. The activity and functional connectivity of local microenvironments were examined under various auditory stimuli. Single cell response patterns were examined using peri-stimulus (PST) histograms and functional connectivity among neighboring cells by the cross renewal density (CRD) histograms. Analysis of the PST histograms suggested that a high percentage of single cells demonstrated different response patterns to different stimuli. Analysis of the CRD histograms suggested, on the one hand, that only small numbers of neighboring cells behaved as if there were direct connections from one cell to another, and that these direct connections appeared to be excitatory. On the other hand, many cell pairs shared input from shared sources which lay outside the local groups. The majority of functional connections were altered by at least one of the stimuli delivered, thus demonstrating the system's plasticity. It is suggested that long-term gates at the synaptic level are responsible for this phenomenon.

Low dose methotrexate in rheumatoid arthritis

A systematic analysis of the efficacy of methotrexate (MTX) in severe rheumatoid arthritis (RA) was carried out. Twenty-one patients with severe classical RA resistant to conventional therapy were treated with 7.5 to 25 mg of oral or intramuscular MTX for 3-114 weeks (mean of 38 weeks). Eleven patients (52.4%) showed definite clinical improvement and a fall in sedimentation rate; some improvement was seen in 5 other patients (23.8%). Two patients were unresponsive. Three patients discontinued MTX, 1 because of acute hepatitis and the other 2 because of noncompliance and fear of toxicity. Abnormal liver function tests reversible with modification of therapy occurred frequently. Other side effects were minor. The results of this uncontrolled study indicate that MTX may be an effective drug for the treatment of severe RA. Double blind trials and longterm followup are needed prior to its widespread use in RA.

Quantification, smoothing, and confidence limits for single-units' histograms

In this article the relationships among firing rate, probability of firing and counts per bin are examined. It is suggested that PSTHs, autocorrelations and crosscorrelations of neuronal activity should all be expressed in units of firing rates (spikes/s), since the values obtained by such scaling are independent of bin size and of total time of measurement. A simple method for these histograms is described. Methods to compute confidence limits for PSTHs, autocorrelations and crosscorrelations are suggested. The computations are based on the null hypothesis that the spike train(s) is (are) the realization of (independent) Poisson-point process(es). The validity and the limitations of these computations methods, when applied to spike trains, are discussed. Methods to smooth out random fluctuation with little distortion of the histogram's shape are described. It is suggested that one can minimize the distortion of the histogram in the time-domain and in the frequency-domain by using a bell-shaped bin whose center point slides continuously along the histogram. The article aims at giving the potential user of the methods some insight for the meaning of the formulae. It describes in detail how the methods are applied in practice and illustrates each method by using real data from single-unit recordings.

Role of the cortical neuron: integrator or coincidence detector?

A model was constructed of the relations between the incoming excitatory postsynaptic potentials and inhibitory postsynaptic potentials to the intracellular membrane potential fluctuations and to the firing rate of a single neuron. From this model, the strength of synapses was assessed in two ways: 1) the ability of several synchronous presynaptic spikes to initiate a postsynaptic spike, termed the synchronous gain of the synapse; and 2) the ability of several asynchronous presynaptic spikes to add a spike to the output spike train, called the asynchronous gain. It was found that for the conditions prevailing in the brain's cortex, the synchronous gain is almost always higher. It appears that the cortical neurons act as coincidence detectors, and that the appropriate code for the higher cortical functions is coincidence and not firing rate.

The coexistence of rheumatoid arthritis and systemic lupus erythematosus: a case report and review of the literature

We describe a patient with longstanding classical erosive rheumatoid arthritis (RA), who after many years developed the clinical and serological manifestations of systemic lupus erythematosus (SLE) including diffuse proliferative lupus nephritis. She fulfilled the ARA preliminary criteria for the classification of SLE as well as the ARA criteria for classical RA. In addition she had antibodies to native DNA, hypocomplementemia, and deposits of immunoglobulins at the dermal-epidermal junction of the non-lesional skin. The rarity of the concurrence of these 2 diseases in the same patient and the discriminating findings with tissue typing analysis suggest that this coexistence may be coincidental.

Systemic lupus erythematosus in the younger patient: survival studies

One hundred eighty-two patients fulfilling the American Rheumatism Association criteria for the classification of systemic lupus erythematosus (SLE) were followed prospectively. Sixty-seven had the onset of SLE before age 21, 32 before age 16, and 35 between age 16 and 20. All patients received similar therapy. Only 4 patients received cytotoxic agents. Malar blush, cellular casts, and profuse proteinuria were significantly more common in the 0-15 compared to the adult group (age 21 or older). Five-year survival was 100% for children with membranous or focal lupus nephritis and 85% for diffuse proliferative lupus nephritis.