HUMORAL AND CELLULAR IMMUNE RESPONSES TO STREPTOCOCCI, INFLUENZA AND OTHER ANTIGENS IN AUSTRALIAN ABORIGINAL SCHOOL CHILDREN

Aboriginal school children with elevated erythrocyte sedimentation rates were selected, and associated features of growth retardation, hyperimmunoglobulinaemia, high streptococcal carrier rates and antibody levels, and high loads of bowel parasite infestation, noted previously, were confirmed. Medical records showed these children to have had significant growth retardation in infancy, which suggested an association with previous protein-calorie malnutrition. Antibody responses of these children to influenza vaccine were significantly poorer than controls, both in the magnitude of antibody rise and the proportion of children showing significant rises in titre. Some improvement in antibody response followed treatment of chronic streptococcal infection, or of bowel parasites. Cell-mediated immune responses, as measured by lymphocyte transformation in vitro in response to specific antigens streptolysin O, tetanus toxoid, non-specific mitogens PHA and streptolysin S, and also by delayed hypersensitivity reactions to monilia antigen on skin testing, were diminished in children with high ESR, relative to controls. However, enhanced cellular responses in the abnormal children occurred to influenza A₂ antigen, and to streptococcal group A polysaccharide, the latter possibly explaining chronic low-grade tissue damage noted previously in these children. These findings are discussed in relation to resistance to infection and the pathogenesis of rheumatic fever, and a possible basis suggested in acquired change in function of the thymus, perhaps related to protein-calorie malnutrition in infancy.     

Migration inhibitory factor production by lymphoid cells of Australian Aboriginal children with moderate protein-calorie malnutrition

Australian Aboriginal children with moderate protein-calorie malnutrition showed a high incidence of impaired production of migration inhibitory factor (MIF) from blood lymphoid cells on in vitro stimulation with Candida albicans antigen. This impairment persisted with the control of infection and nutritional repletion. MIF production to two other antigens, streptolysin-O and lymphocyte membrane extract, was normal or increased.     

ROLE OF TYROSINE RESIDUES ON STRUCTURE-FUNCTION OF FRUCTOSE-1,6-BIPHOSPHATE ALDOLASE FROM CERATITIS CAPITATA

Tyrosine contributions to the structure-function relationship in the fructose-1, 6-biphospate aldolase from C. capitata have been investigated. There are three well defined groups of tyrosine residues with different roles in the structure of the insect aldolase. C-terminal tyrosine residues are essential for the maintenance of the catalytic conformation. Releasing of these residues by carboxypeptidase A treatment results in complex conformational changes according to CD studies. Another tyrosine residue group is located at the active site, and the substrate, fructose-1,6-biphosphate, protects it upon nitration. Chemical modification of this residue results in enzyme activity changes similar to those induced by carboxypeptidase digestion. Enzyme-substrate interaction results in a change of the microenvironment of at least three tyrosine residues per subunit with different accessibility for tetranitromethane.     

Retrograde Pancreatography: New Contributions

The standard technic for pancreatography was modified by using a metallic guide wire in the proximal half of the cannula so as to regulate pressure independently from that applied manually.
The maximum pressure obtained by this method was measured in a polyethylene teflon cannula constructed to correspond to the Wirsung duct. Pressure was five times less when the guide wire was used. Our results in 33 patients correspond to experimental data. Only in 28% of our cases did the amylase rise slightly to a maximum of 290 Somogyi units.
Acinar opacification was attempted by adding Na₂CO₃ to a standard dye solution and was obtained in 20% of the cases (5 of 25). Maximum amylase elevation in this group was 263 Somogyi units.
No complications resulted from the pressure measurements during pancreatography.     

Case Report: Tetraploid Leukemia

A patient with acute leukemia andtetraploid blast cells in the bone marrowis reported. The patient was a 69-yr-oldwhite male who was referred to ourinstitution for chemotherapy. His bonemarrow contained 89% blasts, 30% ofwhich were peroxidase positive. Theclinical history was characterized by arapid, downhill course, and the patientexpired 1 mo after admission in spite ofchemotherapy. At autopsy, nests of viableleukemic cells were still present in thebone marrow. Cytogenetic studies demonstrated a true tetraploid karyotypewith 92 chromosomes. The various mechanisms that may lead to the establishment of a tetraploid clone and theclinical implications of the presence ofthese cells in acute leukemia are discussed. So far as we know, this is thefirst case in which a true tetraploid cloneassociated with human neoplasia hasbeen identified.

Submitted on May 3, 1971 Revised on June 9, 1971 Accepted on June 10, 1971     

警惕非出血性(缺血性)脑卒中转变为出血性脑卒中

缺血性脑卒中约占所有脑卒中的80%.许多最初为缺血性脑卒中病人,后来却转变为出血性脑卒中,这可能会导致医生原发神经病变的进一步恶化.     

Modification of Atrioventricular Nodal Electrophysiology by Selective Radiofrequency Delivery on the Anterior or Posterior Approaches

An analysis was made in 14 isolated and perfused rabbit hearts of the electrophysiological effects of selective radiofrequency (RF) delivery in the anterior (group I, n = 7) or posterior zone (group II, n = 7) of the Koch triangle, with the aim of modifying atrioventricular nodal (AVN) conduction without suppressing 1:1 transmission. After opening the right atrium, RF was delivered (0.5 W) with a 1-mm diameter unipolar electrode positioned in the selected zone until a prolongation of no less than 15% was obtained in the Wenckebach cycle length (WCL). Before and after (30 min) RF, anterograde and retrograde AVN refractoriness and conduction were evaluated, stimulating from the crista terminalis (CT), the interatrial septum (IAS), and from the RV epicardium. After RF, the fallowing percentage increments were observed in group I: AH(CT) = 36%± 9%, AH(IAS) = 38%± 11%, WCL(CT) = 28%± 8%, WCUIAS) = 22%± 6%. functional refractory period (FRP) of the AVN(CT) = 13%±11%, FRP-AVN(IAS) = 13%± 8%, retrograde WCL = 20%±19%. and retrograde FRPVA = 13%± 16%. The increments observed in group II and the significances of the differences with respect to group I were: AH(CT) = 11%± 14% (P < 0.01), AH(IAS) = 19%± 32% (NS), WCL(CT) = 42%± 14% (P < 0.05), WCL(IAS) = 42%± 16% (P<0.01), FRP-AVN(CT) = 28%± 28% (NS). FRP-AVN(IAS) = 21 %± 19% (NS), retrograde WCL = 35%± 24% (NS), and retrograde FRP = 16%± 13% (NS). In both groups, the AH interval variations were not correlated with those of the rest of the parameters analyzed. Truncated nodal function curves suggestive of a dual A V nodal path way were obtained in three experiments, though in only one of them was this observed under basal conditions. In the other two experiments with dual AV nodal physiology only after RF (one from each group), AV nodal reentrant tachycardias were triggered with atrial extrastimulus at coupling intervals equal to or shorter than at those that cause a sudden lengthening of the AH interval. RF delivered in the anterior and posterior zones of the Koch triangle produced effects of different magnitude on the AH interval and Wenckebach cycle length. In the anterior zone the AH interval was prolonged to a greater extent, while in the posterior zone the effects were greater on the Wenckebach cycle length. No correlation existed between the variations in AH interval and Wenckebach cycle length, regardless of where RF was delivered. The evaluation of anterograde AV nodal refractoriness was similar when stimulating from the crista terminalis or from the interatrial septum. By delivering RF, it was possible to induce dual AV nodal physiology and reentrant tachycardias. (PACE 1997; 20[Pt. I]:1261-1273]     

Invasive and Noninvasive Methods to Predict the Long-Term Efficacy of Amiodarone: A Compilation of Clinical Observations Using Meta-Analysis

Background: The method of choice to predial the long-term efficacy of amiodarone in the treatment of complex ventricular arrhythmias is unknown. Whether electrophysiological testing or Holter monitoring better predicts long-term outcome is controversial. Methods and Results: We performed a meta-analysis of trials using electrophysiological testing or electrocardiographic monitoring to predict the efficacy of amiodarone in patients with sustained ventricular tachycardia. Arrhythmia recurrence data were combined after homogeneity testing across trials. Bayesian estimates and 95% credibility intervals were constructed to compare the arrhythmia-free probability among groups. Nine studies using electrophysiological testing (351 patients) and three using Holter monitoring (167 patients) met criteria for inclusion determined a priori. The combined arrhythmia-free probability estimate and credibility intervals were 0.86 (0.78–0.92) for patients rendered noninducible and 0.81 (0.73–0.87) for patients with abolition of ventricular tachycardia during Holter monitoring on amiodarone. With this primary analysis, there was no significant difference between the predictive value of noninducibility during electrophysiological testing and abolition of ventricular tachycardia with Holter. However, if only those electrophysiological studies using at least triple extrastimuli were included, arrhythmia-free probability for patients rendered noninducible increased to 0.96 (0.88–0.99), significantly better than noninvasive testing. Conclusions: Noninducible ventricular tachycardia during electrophysiological testing and abolition of ventricular tachycardia during electrocardiographic monitoring on amiodarone appear equally predictive of long-term amiodarone success, but this conclusion seems dependent on the stimulation protocol used. Although the vield is lower (compared to Holter monitoring), ventricular tachycardia rendered noninducible with a stimulation protocol using triple extrastimuli is the most highly predictive test of long-term amiodarone efficacy.