Progressive systemic sclerosis: radionuclide esophageal scintigraphy and manometry

Radionuclide esophageal scintigraphy (RES) and manometry were used for prospective evaluation of esophageal involvement and disease severity in 11 patients (nine women and two men; median time since diagnosis, 1 year) with progressive systemic sclerosis (PSS). Quantitation of RES included calculation of the percentage of emptying at 30 seconds, while manometry provided measurements of proximal, distal, and lower esophageal sphincter (LES) pressures. The findings of both RES and manometry were abnormal in all 11 patients. There was a high correlation between the percentage of emptying and either distal esophageal pressure (r = .86, P less than .01) or LES pressure (r = .79, P less than .01). No significant correlation was found between the percentage of emptying and proximal esophageal pressure (r = .28, P = .39). RES is a safe, simple procedure that is readily accepted by patients and can be used in place of manometry for the detection and staging of esophageal involvement in PSS.     

Identification of functional domains on von Willebrand factor by binding of tryptic fragments to collagen and to platelets in the presence of ristocetin

With the use of monoclonal antibodies that inhibit the ristocetin- induced binding of von Willebrand factor (VWF) to platelets and the binding to collagen, we have previously identified two distinct tryptic fragments. To prove that these fragments contain the platelet binding or the collagen binding domain, we investigated the direct binding of tryptic fragments of 125I-VWF to platelets in the presence of ristocetin and to collagen fibrils. During the course of the tryptic digestion, there was a rapid and parallel decrease in binding to platelets and collagen. In the first ten minutes, binding decreased greater than 50%; a further decrease to 19% and 29%, respectively, was noted at 90 minutes, but no further decrease was observed thereafter. The bound fragments were eluted from platelets and collagen and analyzed on polyacrylamide gradient gels. The fragments bound to the platelets appeared to be reduced, probably by endogenous reducing substances from the platelets. This was prevented by addition of N- ethylmaleimide during the incubation. After 24 hours of digestion, platelets predominantly bound fragments of 116 kd and collagen bound a single fragment of 48 kd. These fragments are similar to those previously identified with the monoclonal antibodies.     

Physical activity before and after exercise in women with chronic fatigue syndrome

We measured physical activity after strenuous exercise in 20 women with chronic fatigue syndrome (CFS), compared to 20 sedentary healthy volunteers who exercised no more than once per week. Activity was measured for 2 weeks using a portable waist-worn vertical accelerometer. After the first week of activity monitoring, all participants returned for a maximal treadmill test, followed by continued activity monitoring for the second week. Five activity measures were derived from the data: (i) average activity; (ii) total activity; (iii) duration of waking day; (iv) duration; and (v) number of daily rests. A repeated measures ANCOVA was used to determine post- treadmill group differences accounting for pre-treadmill differences. There was a significant reduction in overall average activity after the treadmill test, with the greatest decrease on days 12 through 14. This reduction was accompanied by a significant increase in the duration of the waking day and number of daily rests. Thus, marked exertion does produce changes in activity, but later than self-report would suggest, and are apparently not so severe that CFS patients cannot compensate.      

Thrombotic microangiopathy associated with cryoglobulinemic membranoproliferative glomerulonephritis and hepatitis C

Cryoglobulinemic membranoproliferative glomerulonephritis (MPGN) and increased incidence of vascular thromboses are complications of hepatitis C virus (HCV) infection. This report describes the clinical, laboratory, and renal biopsy findings in two HCV-positive patients with cryoglobulinemic MPGN and thrombotic microangiopathy (TMA). Testing for circulating antiphospholipid antibodies, which are detected in a significant proportion of patients with HCV, was negative in the one case in which it was done. This article discusses the possible cause of the TMA in these two cases.