Effect of macrophage infection by Leishmania on the proliferation of an antigen-specific T-cell line, TPB1, to a non-parasite antigen

The ability of Leishmania mexicana amazonensis to inhibit antigen specific T-cell proliferation against a non-parasite polypeptide antigen, poly(LTyr, LGlu)-poly(DLAla)–poly(LLys), was examined. Infection of mouse peritoneal macrophages by promastigotes blocked the proliferation of the T-cell line, TPB1. This effect was correlated with the level of parasite infection, and the timing of macrophage infection and antigen addition. Peritoneal macrophages from both BALB/b and C57BL/6 mice showed reduced ability to serve as antigen presenting cells.     

Coexistent Paroxysmal Nocturnal and Cold Hemoglobinuria Preceded by Aplastic Anemia: A Case Report and Family Study

This report described a patient with coexistent paroxysmal cold and nocturnal hemoglobinuria. The hemolytic processes were preceded by a periodof marrow aplasia. He demonstrated two complications of prolonged hemolysis and hemoglobinuria, namely iron deficiency and probably "relative folatedeficiency." Forty of his family members were investigated for evidence ofPNH or PCH and none was found. The need for evaluation and follow upof patients with aplastic anemia in terms of PNH was emphasized.

Submitted on April 5, 1963 Accepted on February 10, 1964     

Etidronate disodium for treating hypercalcaemia of malignancy: a double blind, placebo-controlled study

The efficacy of intravenous etidronate disodium in controlling hypercalcaemia of malignancy was evaluated in a double blind, placebo-controlled study. Twenty patients with known malignant disease and hypercalcaemia were randomly assigned on a 2:1 basis to etidronate 7.5 mg kg-1 body weight or placebo for 3-5 days. All patients received 3000 ml saline and 40 mg furosemide per day. Eighteen patients completed the study. Eleven of twelve in the etidronate group reached normocalcaemia compared to two of six in the placebo group (P = 0.05). The etidronate group showed a greater decrease in serum calcium than the placebo group (P less than 0.02). The renal calcium excretion decreased significantly in the etidronate group, but not in the placebo group. A slight increase in serum creatinine was observed in the etidronate group compared to placebo on the first day of treatment. The difference however disappeared the following days. Intravenous etidronate treatment in combination with rehydration and furosemide constitutes a safe and efficient alternative in the treatment of hypercalcaemia of malignancy, although a first approach always should be rehydration.     

Afterdepolarizations and Triggered Activity Develop in a Select Population of Cells (M Cells) in Canine Ventricular Myocardium: The Effects of Acetylstrophanthidin and Bay K 8644

Early afterdepolarizations (EADs) are membrane oscillations that interrupt or retard the repolarization phase of the cardiac action potential, whereas delayed afterdepolarizations (DADs) are oscillations that arise after full repolarization. When EADs and DADs are sufficiently large to depolarize the cell membrane to its voltage threshold, they give rise to triggered action potentials, which are believed to underlie some forms of extrasystolic activity and tachyarrhythmias. EAD- and DAD-induced triggered activity have been described and well characterized in isolated Purkinje fibers exposed to a wide variety of drugs, but are rarely seen in syncytial preparations of ventricular myocardium. These results are inconsistent with those of in vivo studies or experiments involving enzymatically dissociated myocytes. In the present study, we used the cardiotonic agent acetylstrophanthidin (AcS) and the calcium channel agonist Bay K 8644 to provide evidence in support of the hypothesis that induction of prominent EADs, DADs, and triggered activity occurs in a select population of cells in ventricular myocardium. The data indicate that EADs, DADs, and triggered activity produced by digitalis and Bay K 8644 are limited to or more readily induced in the deep subepicardial cell layers of the canine ventricle (M cells). Afterdepolarization-induced triggered activity was never observed in the epicardial or endocardial layers.     

Antibiotic Prophylaxis for Pacemaker Implantation: A Prospective Randomized Trial

Prophylactic antibiotics are frequently prescribed for patients undergoing permanent pacemaker implantation even though data confirming their effectiveness are limited. Five hundred patients requiring elective permanent pacemaker implantation or generator replacement were prospectively randomized either to receive or not receive prophylactic antibiotic treatment at the time of implantation. The implantation site was treated with 10% povidone-iodine solution and 0.5% alcoholic chlorhexidine preoperatively. The wound were inspected for evidence of infection at 3 days and 1, 3, 6 and 12 months postimplantation. Three patients (two receiving prophylactic antibiotics and one no antibiotics) developed pacemaker pocket infection; Staphylococcus aureus was the pathogenic organism in each case (P = 0.56). Eighteen patients developed clinical evidence of superficial wound inflammation requiring antibiotic treatment but not pacemaker removal. Six had received prophylactic antibiotics and 12 had not (P = 0.27). We conclude that pacemaker pocket infection is unusual with careful preoperative skin preparation and close postoperative follow-up. Under these circumstances prophylactic antibiotic treatment is of no practical value.     

Transvenous Atrial Pacing in the Management of Sick Sinus Syndrome Following Surgical Treatment of the Univentricular Heart: Case Report and Review

An 11-year-old boy with univentricular heart type A-III underwent surgical treatment at age 10 with a modified Fontan operation. Six months postoperatively he developed intermittent periods of cyanosis and fatigue associated with profound sinus bradycardia and nodal escape. After demonstrating normal atrioventricular conduction, a transvenous atrial pacemaker was implanted. This produced a marked clinical improvement. Transvenous atrial pacing is a satisfactory method of treating sinus node dysfunction in patients with univentricular heart following the Fontan operation provided that there is normal AV conduction.     

Rate Adaptive Cardiac Pacing Using Right Ventricular Venous Oxygen Saturation: Quantification of Chronotropic Behavior During Daily Activities and Maximal Exercise

Central venous oxygen saturation (S_vO_z) closely reflects cardiac output and tissue oxygen consumption. In the absence of an adequate chronotropic response during exercise, S_vO₂ will decrease and the extent of desaturation maybe used as a parameter for rate adaptive cardiac pacing. Eight patients with sinoatrial disease received a DDDR pacemaker capable of DDDR pacing by sensing either S_VO₂ or piezoelectric detected body movement. Both sensors were programmed to attain a rate of about 100 beats/min during walking, and with the lower and upper rates set at 50% and 90% of age predicted maximum, respectively. Chronotropic behavior of the two sensors were compared in the DDD mode with measurement of sensor responses, during everyday activities (walking, stair climbing, postural changes, and physiological stresses) and at each quartile of workload during a continuous treadmill exercise test. During walking at 2.5 mph, both sensors showed no significant difference in delay time (both react within 15 sees) or half-time (S_VO₂= 36 ± 12 sec and activity 24 ± 3 sec; P = NS), although S_VO₂ driven pacing achieved 90% target rate response slowerthan activity sensing (124 ± 16 sec vs 77 ± 10 sec; P < 0.02). S_VO₂ pacing was associated with a more physiological rate response during walking upslope (68 ± 12 beats/min vs 57 ± 10 beats/ min; P < 0.05), ascending stairs (59 ± 10 beats/min vs 31 ± 6 beats/min; P < 0.05), and standing (34 ± 7 beats/min vs 9 ± 2 beats/min; P < 0.05). The S_vO₂ sensor significantly overpaced in the first quartile of exercise (51.8 ± 25.6% in excess of heart rate expected from workload), but the rate was within 20% of expected for the remainder of exercise. “Underpacing” was observed with the activity sensor at the higher workload. In conclusion, the S_vO₂ sensor demonstrated a more physiological response to activities of daily living compared with the activity sensor. Using a quantitative method, the speed of onset of rate response of the S_vO₂ sensor was comparable to activity sensing, and was more proportional in rate response. Significant overpacing occurs at the beginning of exercise during S_VO₂ driven pacing, which may be improved with the use of a curvilinear algorithm.