Platelets in Early Antibody-Mediated Rejection of Renal Transplants

Antibody-mediated rejection is a major complication in renal transplantation. The pathologic manifestations of acute antibody-mediated rejection that has progressed to functional impairment of a renal transplant have been defined in clinical biopsy specimens. However, the initial stages of the process are difficult to resolve with the unavoidable variables of clinical studies. We devised a model of renal transplantation to elucidate the initial stages of humoral rejection. Kidneys were orthotopically allografted to immunodeficient mice. After perioperative inflammation subsided, donor-specific alloantibodies were passively transferred to the recipient. Within 1 hour after a single transfer of antibodies, C4d was deposited diffusely on capillaries, and von Willebrand factor released from endothelial cells coated intravascular platelet aggregates. Platelet-transported inflammatory mediators platelet factor 4 and serotonin accumulated in the graft at 100- to 1000-fold higher concentrations compared with other platelet-transported chemokines. Activated platelets that expressed P-selectin attached to vascular endothelium and macrophages. These intragraft inflammatory changes were accompanied by evidence of acute endothelial injury. Repeated transfers of alloantibodies over 1 week sustained high levels of platelet factor 4 and serotonin. Platelet depletion decreased platelet mediators and altered the accumulation of macrophages. These data indicate that platelets augment early inflammation in response to donor-specific antibodies and that platelet-derived mediators may be markers of evolving alloantibody responses.     

Hailey–Hailey disease improved by fractional CO2 laser

Hailey–Hailey disease (HHD), also known as benign familial pemphigus, is an autosomal dominant skin condition that affects the adhesion of epidermal keratinocytes. Although the initial manifestation of flaccid vesicles on erythematous or normal skin in flexure sites frequently goes unnoticed, large, macerated, exudative plaques of superficial erosions with crusting are observed at the time of diagnosis. There is no specific treatment for HHD, and most cases are symptomatically supported. However, infrared laser ablation has been somewhat helpful. We present a case successfully treated with fractional CO₂ laser showing a long-term favourable outcome and no adverse effects. Thus, this modality could be an alternative to full ablation for this condition.     

Radiation dose reduction during hysterosalpingography: an application of scanning-beam digital radiography

Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.     

Lack of efficacy of thickened feeding as treatment for gastroesophageal reflux

The efficacy of thickened feedings for the treatment of gastroesophageal reflux in infancy was evaluated. Fifty-two infants were examined with prolonged pH monitoring of the distal esophagus after feedings of apple juice or apple juice thickened with rice cereal. All infants had a minimum of three feedings of both thickened and unthickened juice. The recordings of distal esophageal pH were analyzed for the percent of time the pH was less than 4 in the first 2 hours after each feeding. The infants were maintained in the following positions after feeding: prone (n = 29), prone-board with the head elevated 30 degrees from horizontal (n = 29), supine (n = 7), and unrestricted (n = 21). We found no significant difference in the percent of time with reflux with thickened versus unthickened feedings except in those infants maintained in the 30-degree prone position. In the first 2 hours after eating thickened juice, infants maintained in this position had increased esophageal reflux time (P less than 0.006). Further analysis revealed that 33% of the infants had a greater than 30% increase in esophageal reflux time after thickened feedings. Our study suggests that the immediate effect of thickened feedings on gastroesophageal reflux in infants is unpredictable.     

Radioimmunoassay for amatoxins by use of a rapid, 125I-tracer-based system

In this new radioimmunoassay system for determination of amatoxins in urine and plasma, a novel chemical approach is used for antigen and 125I-tracer production, based on a detoxified alpha-amanitin derivative (aldoamanitin). Total assay time, including data processing, is less than 100 min. The lowest detectable concentration is 1 microgram/L for urine, 0.1 microgram/L for plasma. In the clinically significant range, within-run CVs are less than 8%. This new 125I-based assay is a significant improvement over existing 3H technology in terms of speed, precision, and freedom from interference.