Loss of ultrafiltration in continuous ambulatory peritoneal dialysis (CAPD)

Fifteen patients on long-term continuous ambulatory peritoneal dialysis (CAPD) were assessed with respect to net ultrafiltration capacity. Eight patients were defined as having good and seven as having poor ultrafiltration on the basis of net ultrafiltrate obtained/mmol glucose infused. Subsequently, dialysate was sampled at times 0, 1, 15, 30, 60, 90, 120, 180, and 240 min. No difference in residual volume was observed between the groups. A significantly greater decrease in dialysate sodium during the initial dialysis period in those patients with good as compared to those with poor ultrafiltration occurred, reflecting a greater transcapillary movement of electrolyte poor ultrafiltrate. In those with good ultrafiltration, glucose transfer was normal in five and rapid in three, suggesting the latter had low rates of lymphatic reabsorption. Five of seven patients with poor ultrafiltration had no fall in dialysate sodium in association with a high rate of glucose transfer, suggesting a low rate of transcapillary water movement and normal to high lymphatic absorption. Two patients with low ultrafiltration had an initial fall in dialysate sodium with a normal glucose transfer and thus net ultrafiltration is low due to elevated lymphatic reabsorption. We thus propose that the relative contribution of transcapillary water movement and lymphatic reabsorption can be determined by assessing net ultrafiltration and dialysate sodium concentration in conjunction with solute transfer.     

Interobserver variation in the interpretation of abdominal radiographs

A total of 140 sets of abdominal radiographs were reviewed independently by four qualified diagnostic radiologists. The degree of interobserver agreement was determined by calculating kappa values for 19 commonly used radiographic signs and diagnoses. There was fair to excellent interobserver agreement for 11 signs and diagnoses and poor agreement for the remaining eight. The signs and diagnoses for which agreement is poor cannot be considered reliable and include particularly large bowel obstruction and nonspecific gas pattern.     

Effect of intersection spacing on MR image contrast and study time

The effects of section separation on image contrast and calculated T1 relaxation times were investigated in healthy volunteers and a phantom using an early commercial version magnetic resonance imaging system. The effects are explained qualitatively on the basis of side lobes of excitation occurring outside the selected section resulting in reduction of the time permitted for T1 relaxation. The options for dealing with imperfect section selection, including separation of the sections (i.e., leaving gaps) and nonsequential excitation, are illustrated and the trade-offs involved in each explained.     

Combined testing for antibodies to rubella non-structural and envelope proteins sentinels infections in two outbreaks

Two separate outbreaks of Rubella occurred in Hamilton, Ontario, Canada, 7 yrs apart, with a peak incidence for both in the month of April. A total of 138 cases, 51 in 1978 and 87 in 1985, was observed, the majority being in adolescents and young adults 15-25 years of age. Cases were diagnosed by the presence of Rubella IgM antibody or the combination of a negative passive hemagglutination (Rubacell-Abbott) and a positive enzyme immunoassay (EIA) or hemagglutination inhibition (HI) test on a single serum or by seroconversion for Rubella IgG antibody. Routine screening of sera with the Rubacell test, which measures antibodies to nonstructural rubella proteins together with HI or EIA testing of the negatives, served as a sentinel for rubella infection in the community during both outbreaks. Rubacell antibodies usually appeared 2-3 wk after onset of infections, and when present contained either or both IgG and IgM. Only 8/103 cases had a history of Rubella vaccination. Two of three products of conception yielded rubella virus in cell culture.     

The ultrasonic detection of platelet aggregates

The echogenicity of platelet aggregates in platelet-rich plasma and whole blood was evaluated in stirring and flowing in vitro models. Real-time two dimensional ultrasonic images were obtained with transducers operating at 3.0, 5.0, 10 and 12 mHz. Platelet-rich plasma was not echogenic. The addition of adenosine diphosphate (ADP) resulted in the formation of multiple, discrete echoes that increased in size and intensity. This echogenicity was time and dose-dependent and could be quantitated by videodensitometry. Whole blood was echogenic, but the addition of ADP resulted in a time and dose-dependent increase in the size and echogenicity of the reflections. The overall echogenicity of whole blood declined with the development of platelet aggregates. There is inter- and intra-aggregate variability in the echogenicity of aggregates. Aggregates were best seen with transducers operating at the higher frequencies. These results imply that the detection of in vivo platelet aggregates may be feasible with ultrasonic imaging.     

Perforation of the inferior vena cava with aortic and vertebral penetration by a suprarenal Greenfield filter

Various complications have been reported after insertion of the Greenfield filter. This report describes an unusual complication after suprarenal placement of this filter: spreading of the filter struts, with perforation of the inferior vena cava, and penetration of the aorta and a vertebral body, followed by fracture of one of the struts.