Effect of a patellar realignment brace on patellofemoral relationships: Evaluation with kinematic MR imaging

The effect of a newly developed patellar realignment brace was evaluated in 21 patellofemoral joints (19 patients) with patellar subluxation (13 joints with lateral subluxation and eight with medial subluxation) by using active-movement, loaded kinematic magnetic resonance (MR) imaging. Sixteen patellofemoral joints (76%) demonstrated a qualitative correction of or improvement in patellar subluxation (ie, centralization of the patella or a decrease in the displacement of the patella) after application of the brace. Four of the five “failures” occurred in patellofemoral joints that had patella alta and/or dysplastic bone anatomy. These results indicate that the patellar realignment brace was able to counteract patellar subluxation in the majority of patellofemoral joints studied, as shown by active-movement, loaded kinematic MR imaging. This brace appears to be useful for conservative treatment of patients with patellofemoral joint pain secondary to patellar malalignment and maltracking.     

Massive Immune Hemolysis Caused by Anti-D After Dual Kidney Transplantation

Massive immune hemolysis due to passenger lymphocyte-derived anti-D has not been reported in renal transplantation. A 50-year-old (B-positive) male received a dual deceased-donor kidney transplant (B-negative) for diabetic renal failure. Two weeks post-transplant, the patient developed severe hemolytic anemia. The donor anti-D titer was 1:8. The recipient anti-D titer (zero pre-transplant) increased from 1:4 to 1:16 over 4 days. Rapid hemolysis caused severe anemia, minimum Hb = 4.2 g/dL, while selectively lysing the patient's autologous red cells during this time. The hemolytic anemia did not impair the allografts and subsided without monoclonal B-cell pharmacotherapy or apheresis. The anti-D titer decreased to barely detectable levels at four months and had cleared when checked 2 years post-transplant. Transfusion support subsided after two months. If complications of anemia can be avoided, the deleterious effects of hemolysis may be well tolerated by renal allografts using antigen negative transfusion alone.     

Cardioprotective effects of diltiazem when given before, during or delayed after infusion of norepinephrine in anesthetized dogs

Catecholamine excess has been shown to produce 2 distinct forms of irreversible myocardial necrosis termed contraction band lesions. Calcium channel blocking agents provided a variable protective effect from these contraction band lesions. The purpose of this study was to determine the temporal responses of the most effective of these blocking agents, diltiazem, when given before, simultaneous with or after an initial exposure to a necrogenic infusion of norepinephrine (NE). Forty-one adult mongrel dogs were anesthetized with sodium pentobarbital (32 mg/kg) and infused with saline solution or NE (4 micrograms/kg/min) for 60 minutes or diltiazem at a rate of 20 micrograms/kg/min for the first 5 minutes and 10 micrograms/kg/min for the remaining 70 minutes. Diltiazem was infused as pretreatment 15 minutes before continued infusion with NE for 60 minutes, simultaneously infused with NE for 60 minutes or delayed 30 minutes after the start of NE infusion. Diltiazem alone exhibited no significant effect on hemodynamics, but pretreatment with diltiazem was able to moderate the rapid NE-induced increases in heart rate. NE infusion produced significant numbers of the 2 forms of contraction band lesions: (1) paradiscal contraction band lesions involving a small portion of the cell adjacent to the disc, and (2) holocytic contraction band lesions involving the entire cell. Diltiazem reduced the number of contraction band lesions, particularly the holocytic contraction band lesions, provided diltiazem was available before the insult and massive influx of calcium with a pharmacologic dose of NE. Although the exact mechanism of diltiazem's cardioprotective properties is not known, the timing of drug administration does appear to affect the degree of protection.