IgA rheumatoid factor and IgG dietary protein antibodies are associated in rheumatoid arthritis

This study sought to determine whether patients with rheumatoid arthritis (RA) were immunologically sensitised to dietary protein (DP). Using an enzyme linked immunosorbent assay (ELISA), antibodies to milk and wheat proteins were measured in 93 unselected out-patients with classical or definite RA. Of these 93, 53 had raised levels of IgG antibodies to one or both dietary proteins (DP). In the DP antibody positive group, 48 patients (90%) also had raised levels of IgA rheumatoid factor (measured by ELISA) while only 7 (17%) of the 40 DP antibody negative patients had detectable IgA RF; P less than 0.02. There was no association between IgM rheumatoid factor and dietary protein antibodies. These results demonstrate that in RA, raised levels of IgA RF are associated with an increased IgG response to antigens which enter the body through the gastrointestinal tract. A breakdown in gastrointestinal tolerance to dietary antigens may play a role in the immunopathogenesis of RA in these patients who might therefore benefit from dietary manipulation.

Extracellular potassium ion dynamics and ventricular arrhythmias in the canine heart

The relation between extracellular potassium ion activity [( K+]o) and ventricular tachyarrhythmias was studied in an open chest canine model with the use of two protocols. In Protocol I, potassium chloride was administered into the proximal left anterior descending coronary artery at a rate of 0.125 mEq/min for either 20 min or until [K+]o = 20 mEq/liter, whichever came first. In Protocol II, the proximal left anterior descending coronary artery was occluded in one step and was reperfused 20 min later. Fifteen dogs were subjected to Protocol I, nine of which were also subjected to Protocol II. In the latter group, a recovery period of greater than or equal to 1 h separated the two protocols. Local K+ and intramyocardial activities were recorded with use of bifunctional ion-sensitive plunge electrodes at multiple sites located in the region of the left ventricle perfused by the left anterior descending artery and at one site outside of this region. The following variables were recorded and analyzed: Lead II electrocardiogram, heart rate, systemic arterial blood pressure, local [K+]o and its time derivative (dK+/dt), local electrograms and ventricular arrhythmias. Maximal [K+]o and dK+/dt were 23 +/- 3 mEq/liter and 9 +/- 1 mEq/liter per min in Protocol I and 14 +/- 1 mEq/liter and 3 +/- 1 mEq/liter per min in Protocol II, respectively. In both protocols, the occurrence of ventricular arrhythmias correlated with [K+]o (p less than 0.02) as well as with dK+/dt (p less than 0.05). Ventricular arrhythmias were more frequent and more severe in Protocol II than in Protocol I (p less than 0.05). Therefore, whereas K+ dynamics were more pronounced in Protocol I, ventricular arrhythmias were more severe in Protocol II. This occurrence was apparently due, at least in part, to less heterogeneous changes in K+ gradients during constant K+ infusion. It was concluded that, in addition to the magnitude of [K+]o, the rate of change of this variable (that is, dK+/dt) apparently plays an important role in the genesis of ischemic ventricular arrhythmias.

Spasticity: quantitative measurements as a basis for assessing effectiveness of therapeutic intervention

Spasticity, a common problem in upper motor neuron lesions, frequently results in uncontrolled involuntary motion that interferes with function. A quantifiable method related to the mechanical output of the muscle is needed to test and improve therapeutic intervention. A sinusoidal displacement of 5 degrees was used to measure elastic and viscous stiffness around the ankle at frequencies from 3 to 12Hz. To isolate viscoelastic response, the influences of inertia and equipment drag were eliminated. Test-retest correlation values were 0.953 for elastic and 0.992 for viscous stiffness. The elastic stiffness in 13 spastic subjects under nerve block was significantly higher than that of 13 healthy subjects (p less than or equal to 0.05), indicating early changes associated with contracture. Elastic and viscous response is expressed by the total stiffness vector containing both components, the Nyquist diagram. This diagram's pathlength from 3 to 12Hz was calculated and showed high test-retest reliability in healthy subjects. The median pathlength value for the spastic group was 98 Newton-meters/radian (N-m/rad) and, for the normal group, 24N-m/rad, a statistically significant difference (p less than or equal to 0.0001). A mathematical model of the spastic response shows that the Nyquist diagram's pathlength relates to reflex loop gain and is independent of the shift in passive properties. The model predicts a shift in passive properties during spastic responses relative to responses measured during nerve block. Thus, subtraction of passive responses measured during nerve block may not isolate the remaining reflex response, but the pathlength measure relating to the reflex response gain was unaffected, allowing evaluation of therapeutic intervention effectiveness.

Association between villous atrophy in rheumatoid arthritis and a rheumatoid factor and gliadin-specific IgG

93 patients with rheumatoid arthritis (RA) were examined for histological or other evidence of gut abnormalities. 44 had raised levels of IgG to gliadin, and of these 38 (86%) were also positive for IgA rheumatoid factor (RF). 24 patients (15 with raised levels of IgA RF and wheat protein IgG [AB+] and 9 with normal levels of both antibodies [AB-]) underwent jejunal biopsy. 6 of the AB+ and 1 of the AB- patients had villous atrophy. The AB+ group had lower villous surface/volume ratio and small intestinal lactase concentrations than did the AB- group or age-matched controls. There was no significant difference between the two groups of RA patients in disease severity or treatment regimen. The findings suggest that the gut may play a more important part in the immunopathogenesis of some cases of RA than in others, and that the former may be identified by raised levels of IgA RF and wheat protein IgG.

Gene encoding the beta subunit of S100 protein is on chromosome 21: implications for Down syndrome

S100 protein is a calcium-binding protein found predominantly in the vertebrate nervous system. Genomic and complementary DNA probes were used in conjunction with a panel of rodent-human somatic cell hybrids to assign the gene for the beta subunit of S100 protein to the distal half of the long arm of human chromosome 21. This gene was identified as a candidate sequence which, when expressed in the trisomic state, may underlie the neurologic disturbances in Down syndrome.

Gait abnormalities in hemiplegia: their correction by ankle-foot orthoses

Hemiparetic gait is characterized by slow speed and poorly coordinated movements. Because the values of gait parameters vary with changes in speed, the slow speed that is typical of hemiparetic gait necessitates applying controls for the influence of speed when comparing hemiparetic and able-bodied persons. Gait kinetics and kinematics were measured in seven hemiparetic and seven able-bodied adults to compare their gait patterns at similar speeds and to assess the effectiveness of ankle-foot orthoses which were double-stopped in 5 degrees of dorsiflexion or 5 degrees of plantarflexion. Hemiparetic persons ambulating without the orthoses had a shorter step length, longer duration stance, and shorter duration swing than normal. They displayed greater than normal flexion of the affected hip during midstance, which, by putting the center of mass farther in front of the knee, may explain the increased knee extension moment due to vertical force. Affected hip adduction during single support was less in hemiparetic persons than in able-bodied persons, indicating a decreased lateral shift to the paretic side. During the swing phase, the affected limbs of hemiparetic persons were in less knee flexion and less dorsiflexion than normal, necessitating circumduction to achieve toe clearance. Ankle-foot orthoses increased walking speed to normalize heelstrike duration through use of an optimally adjusted plantarflexion stop. An improperly adjusted orthosis may produce an exaggerated knee flexion moment resulting in knee instability.

Preservation of endothelial cell structure and function by intracoronary perfluorochemical in a canine preparation of reperfusion

To determine the effect of intracoronary perfluorochemical on endothelial cell structure and function, 16 dogs were randomized to receive either low-dose (15 ml/kg) intracoronary perfluorochemical (Fluosol-DA) or saline after 90 min of proximal occlusion of the left anterior descending coronary artery (LAD). The animals underwent reperfusion for 60 min with the introduction of perfluorochemical or saline 5 to 10 min after the onset of reperfusion. Endothelium-dependent coronary vasodilatory reserve was determined in vivo both at baseline and 1 hr after reperfusion by infusion of acetylcholine and then serotonin into the distal LAD bed in 12 animals (six in each group). Both agonists significantly increased regional flow measured by 133Xe washout in the two groups before occlusion, but at 1 hr after reperfusion only animals given perfluorochemical demonstrated a significant increase in flow. Vasodilatory reserve was assessed in vitro with cumulative dose-response curves to acetylcholine on LAD rings proximal and distal to the snare in all animals. These studies demonstrated a significant reduction in endothelial cell-mediated relaxation of epicardial arterial segments in the ischemic segment of control but not treated animals. Light microscopy revealed the presence of neutrophils within vessels in the ischemic zones in control animals only. Electron microscopy showed capillary obstruction by endothelial cell protrusions and neutrophil and red cell plugging in control animals in the ischemic region but an intact endothelium and predominantly unobstructed capillaries in treated animals. These findings suggest that the structural and functional endothelial damage after reperfusion may be prevented by the administration of intracoronary perfluorochemical after the onset of reperfusion.

The role of the biomechanics laboratory in the analysis of the gait of individuals with arthritis

The function of a biomechanics laboratory is to measure those aspects of an individual patient's performance that cannot be quantitatively assessed in the clinical setting. Essential equipment provides the ability to measure gait events, ground reactive forces, kinematics (movement of the body and its segments in 3 dimensions), electromyographic activity, and oxygen consumption. A minicomputer with video screen is required to process the data and allow visual checks of the functioning of the system. Such things as moments around joints and deforming forces may be calculated from the measured variables. Illustrations are given of a schematic laboratory system, computer generated stick diagrams, real-time changes in forces, moment-arms, moments, and excursions, in addition to the alteration of these variables in tibial nerve paralysis and degenerative arthritis of the knee.

Fixation effects on synaptic vesicle density in neuromuscular junctions of young and old mice

It was previously reported that in soleus neuromuscular junctions of old mice, synaptic vesicle density was decreased while transmitter release was increased (compared to results in young mice). In the present study, two hypotheses that might resolve this disparity were tested. The first was that the density of readily releasable vesicles close to the preterminal membrane, rather than those in the whole terminal, would correlate with the physiological results. This hypothesis was excluded because both vesicle density in the 200 nm region just within the presynaptic terminal membrane, and total vesicle density were similarly reduced in old soleus junctions. The second hypothesis was that more transmitter was released during fixation at old than at young neuromuscular junctions, leading to an age-related depletion of vesicles. This was tested by counting vesicles in muscles fixed after transmission block was attained in Krebs solution lacking calcium, and by direct recording of quantal release during conventional fixation. This second hypothesis was excluded: in neuromuscular junctions exposed to zero-calcium Krebs solution before fixation, the age-related reduction in vesicle density was still present, and intracellular recording revealed only a slight increase in quantal transmitter release during fixation. Therefore, as discussed, other mechanisms must be considered.

Phasic effects of postganglionic vagal stimulation on atrioventricular nodal conduction

The effects of postganglionic vagal stimulation (PGVS) on atrioventricular nodal conduction were studied in 15 rabbit atrial-atrioventricular nodal preparations. PGVS was introduced, and sinus cycle length was scanned as independent bursts of subthreshold stimuli were produced in the sinus node and atrioventricular node (AVN). Changes in conduction of atrial impulses to the bundle of His were studied under the following experimental conditions: changes in sinus cycle length resulting from vagal influence on the sinus node, direct vagal stimulation exclusively to the AVN, and during both simultaneous or nonsimultaneous vagal stimulation to sinus node and AVN. The results of the present study showed that the direct effect of PGVS on AVN conduction time at a constant sinus cycle length is phase dependent with maximal prolongation achieved in the first or second beat after introduction of the burst. The interval between the onset of PGVS producing maximal prolongation of conduction time and the following atrial beat was designated the "optimal effective phase." It was shown that the optimal effective phase was a constant parameter for a given preparation and in the present experiments was 321 +/- 16 ms. However, when PGVS was introduced in combination to both nodes while scanning the cycle length, AVN conduction was variable, reflecting both the direct effects of PGVS on the AVN as well as the indirect effects resulting from changes in the sinus cycle length. Notably, it was found that simultaneous PGVS to both the sinus node and AVN usually diminished, whereas appropriate nonsimultaneous PGVS accentuated the typical phasic dependency of AVN conduction time. Additionally, vagally induced prolongation of the sinus cycle length was found to be accompanied by changes in the time of depolarization of the inputs to the AVN, thus influencing AVN conduction and facilitating reentry. These interactions between changes in the sinus cycle length and concomitant changes in the effectiveness of vagal influence on the AVN can be used to explain complexities of AVN conduction during increased vagal activity.

Gait abnormalities in peroneal nerve paralysis and their corrections by orthoses: a biomechanical study

Stroke, brain injury, incomplete spinal cord injuries, and peripheral neuropathies frequently result in dysfunction of the foot dorsiflexors and evertors. A controlled examination of aspects of these disabilities was conducted with normal volunteers who underwent a temporary peroneal nerve block. The effects of peroneal nerve paralysis were analyzed to quantitatively describe the resulting gait abnormalities and to assess the effectiveness of orthoses in restoring a normal gait pattern. Kinematic and kinetic measurements were made during normal ambulation, ambulation with a right peroneal nerve paralysis, and ambulation with a paralysis and an ankle-foot orthosis (AFO) with three different adjustments: a posterior stop set in 5 degrees plantarflexion, a posterior stop set in 5 degrees dorsiflexion, and spring-assisted dorsiflexion. The peroneal paralysis produced abnormalities during both the stance and swing phases of gait. During early stance there was a decrease in the length of the heelstrike phase and a reduction in the peak plantarflexion moment (p less than 0.01). During midstance there was an increase in the range of inversion-eversion achieved suggesting medial-lateral instability (p less than 0.01). The second vertical force peak and the aft-shear force peak were reduced (p less than 0.05) as were the peak dorsiflexion moment and the opposite steplength (p less than 0.01). These reductions are believed to be due to medial-lateral instability during pushoff. Subjects demonstrated a steppage gait during swing phase and increased inversion just prior to heelstrike (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of the site of stimulation on atrioventricular nodal refractory periods and the effect of verapamil

The refractory periods of the atrioventricular (AV) node appear dependent on the pattern of AV nodal input. In 21 superfused AV rabbit heart preparations stimulated from each of the 2 principal input regions, crista terminalis or atrial septum, the effect of changing the site of stimulation of the AV nodal refractoriness and the relative effect of verapamil on AV nodal refractoriness was determined. In 6 of 21 preparations the functional AV refractory curve became discontinuous only when stimulation was applied at the atrial septum and suggested dual AV nodal pathways (dual pathways group). In the 15 other preparations no interruption of the curve occurred with either crista terminalis or atrial septal stimulation (normal conduction group). In the normal conduction group, the difference in the effective refractory period of the AV node obtained by crista terminalis vs atrial septal stimulation was not significant (154 +/- 25 vs 150 +/- 28 ms). However, the functional refractory period was significantly longer with crista terminalis vs atrial septal stimulation (232 +/- 19 vs 239 +/- 19 ms, p less than 0.001). After verapamil administration, the effective and functional refractory periods during crista terminalis vs atrial septal stimulation were prolonged to 270 +/- 49 vs 285 +/- 55 ms (p less than 0.01) and 335 +/- 43 vs 351 +/- 41 ms (p less than 0.001), respectively. Thus, the difference in refractory periods associated with changing the stimulation site was exaggerated with verapamil.(ABSTRACT TRUNCATED AT 250 WORDS)

Molecular pathogenesis of equine coital exanthema: restriction endonuclease digestions of EHV-3 DNA and indications of a unique XbaI cleavage site

Equine herpesvirus type 3 (EHV-3) DNA, isolated from purified virions of the large-plaque strain, was digested with the restriction endonucleases XbaI, Bg/II, EcoRI, and HindIII. Several lines of evidence indicated that the DNA extracted from purified virions was composed of long (L) and short (S) components and was present as two isomeric forms, P and IS. The evidence included: (i) after electrophoresis on agarose gels, the summed molecular weights of the digestion products exceeded that expected from intact, unit size DNA; (ii) quantitative measurements of radioactivity (molar ratios) indicated 'minor bands' (0.5 M) interspersed among the major (1.0 M) bands; and (iii) a brief digestion with lambda-5'-exonuclease, prior to digestion with restriction endonuclease, resulted in the loss of some submolar and molar ratio bands, indicative of three termini. A preliminary fragment linkage map of the XbaI digestion products revealed EHV-3 DNA to contain only one recognition site in the unique sequence of the S component. From this linkage map, the size of the S component was deduced to be (22.3 +/- 5) X 10(6) molecular weight.

Acute megakaryoblastic leukaemia associated with intrinsic platelet dysfunction and constitution ring 21 chromosome in a young boy

A 3-year-old boy with pancytopenia and a paucity of circulating blast cells was found to have acute megakaryoblastic leukaemia. Histopathologic investigation of the bone marrow biopsy disclosed replacement by megakaryoblasts and mild-to-moderate reticulin fibrosis, the megakaryocytic origin of these cells was confirmed by their staining properties and by cross-reactivity with rabbit anti-rat platelet serum. Treatment with adriamycin and cytosine arabinoside induced a complete remission of this otherwise rapidly fatal disease. Before chemotherapy, the patient's platelets showed decreased aggregation in response to thrombin and adenosine diphosphate, as well as a defective thrombin-induced serotonin release reaction. Neither functional defect resolved after remission induction, indicating that the platelets were intrinsically abnormal. Most striking was the finding of a constitution chromosomal defect, a ring No. 21 chromosome, in addition to an abnormal malignant stem line. This appears to be the first reported instance of a constitutional r(21) chromosome associated with acute leukaemia.

Kidney complications

Diabetic glomerulosclerosis in man and in all spontaneous-onset and chemically induced diabetes in experimental models is characterized by diffuse increase in mesangial matrix and glomerular basement membrane thickening. The most prominent features of the biochemical changes in the glomerular basement membrane are increase in the collagen-like components, decreased sialic acid, and increased glucosylation. However, the heterogeneity of the various glycoprotein components of the glomerular basement membrane and related components of the mesangium make comparative biochemistry difficult. Increased glomerular blood flow with no apparent alterations in the glomerular filtration coefficient in diabetes may be attributed to altered vascular control mechanisms which may include both hormonal mediation as well as changes in end-organ responsiveness. Although proteinuria is a common manifestation of diabetic involvement of the glomerulus, there is little biochemical or physiologic evidence as to the specific causes of increased glomerular filtration apparatus permeability. Further information as to the pathogenesis of diabetic vascular disease of the kidney and the ability to reverse pathologic changes by correction of the metabolic milieu will require analysis of carefully selected animal models. Particular care in experimental design must include the ability to integrate pathology, physiology, and biochemistry in each model in order to relate the information to human renal diabetic complications.

Hydropathy in England 1840-70

Images

Short-latency somatosensory evoked potentials in multiple sclerosis. Comparison with auditory and visual evoked potentials

Short-latency somatosensory potentials after median nerve stimulation were recorded in 17 patients with clinically definite cases of multiple sclerosis and in 15 patients with probable, possible, or suspected cases. Abnormalities, usually prolongation of component wave latencies, were found in 20 patients, often with normal clinicaly sensory testing. Abnormalities in brief auditory evoked potentials were found less often but were significantly more frequent in the group with clinically definite cases. Pattern evoked visual potentials may have been more useful in identifying early cases. The recording of all three evoked potentials showed an abnormality of at least one in most patients.

Subcellular distribution and storage form of rat renal renin

The subcellular distribution and nature of rat renal renin has been investigated by means of analytical subcellular fractionation and gel filtration on Sephadex G-100. During differential centrifugation, renin activity was recovered mainly in soluble and heavy mitochondrial fractions. On sucrose gradient centrifugation in either a conventional or in a B XIV zonal rotor, renin activity equilibrated at 1.54 M sucrose and was partially resolved from marker enzymes for mitochondria (succinate dehydrogenase), lysosomes (acid phosphatase), plasma membranes (alkaline phosphatase), and peroxisomes (catalase). On gel filtration of the soluble or extracts of the renin-granular fractions on Sephadex G-100, renin activity eluted as a single peak with an apparent molecular weight (MW) of 42,000; no change in activity was found when these fractions were acidified to pH 3.0. When kidney homogenates were prepared in the presence of the proteolytic inhibitor N-ethylmaleimide (NEM, 10 mM), whereas the renin from the granular fractions displayed a MW of 44,000, that from the soluble fraction was apparently higher (69,000). Addition of NEM (10 mM) to the soluble fraction previously shown to contain only the low MW form of renin also resulted in an apparently high MW form of renin. These results indicate that rat renal renin is associated with a mechanically fragile, distinct type of subcellular organelle. Renin within this structure is of the low MW form and is not acid activatable. The soluble fraction, however, contains a factor(s) that, in the presence of NEM, combines with the low MW renin to form a complex of apparently high MW.

The long term effect of sphincter preserving operations for rectal carcinoma on function of the anal sphincter in man

Anal function was studied in 20 normal subjects and in 20 patients who had undergone sphincter-saving resection of the rectum for carcinoma. In each the anastomosis had been constructed 3-7 cm from the anal verge. Inhibition of the internal sphincter was judged to have taken place when distension of a balloon 10 cm from the anal verge produced an immediate fall of at least 20 per cent in resting anal pressure as measured by a balloon probe: inhibition of the external sphincter in response to the same stimulus was defined as complete cessation of EMG activity. Threshold for sensation was the minimal volume of balloon distension required to elicit a response. Maximum tolerable volume was the largest volume of distension tolerated. Inhibition of the activity of the internal sphincter was found in all controls and in 17 of 20 patients. External sphincter activity was inhibited in 16 of 20 controls and 11 of 19 patients. Threshold for sensation and its quality were similar in both groups. Patients had more frequent bowel actions than the controls which is probably explained by significant reductions in resting and pressure and maximum tolerable volume found in patients. These results suggest that some, at least, of the physiological mechanisms subserving continence remain intact after complete or nearly complete excision of the rectum.

Studies on red-cell aplasia: IX. Ferrokinetics during remission of the disease

Ferrokinetic studies and external organ measurements of radioiron were performed on five patients with pure red-cell aplasia (PRCA) in remission. One patient with PRCA in relapse was also studied. Of those in remission, one patient had erythroid hyperplasia and ineffective erythropoiesis after the remission occurred. This was indicated by a very short 59Fe clearance rate and reduced red-cell 59Fe incorporation, a marked increase of the erythron iron turnover over the fixed red-cell iron turnover, and a prolonged marrow transit time. These indices were normal three years later. Four patients had normal effective erythropoiesis while in remission. Two patients had an extended marrow distribution. These studies indicate that some cases of PRCA evolve into a state of ineffective erythropoiesis with erythroid hyperplasia. It is possible that in some patients, primary refractory anemia with ineffective erythropoiesis may be related to PRCA because of the evolution from one state into the other. Alternatively, a second pathologic process may have been acquired between the PRCA and normal hematopoiesis.

Dental acupuncture

Recently the opportunity arose to perform certain operative dentistry on a patient using acupuncture as an analgesic.