Overrepresentation of HLA-DQ2 in small intestinal neuroendocrine tumor patients.

PURPOSE: To investigate whether celiac disease risk haplotypes HLA-DQ2 and DQ8 also increase the risk for developing small intestinal neuroendocrine tumor (SI-NET). METHODS: Thirty-five patients with serotonin-producing jejunal and ileal SI-NET were examined with HLA-DQ genotyping and serology for IgA anti-tissue transglutaminase (tTG) antibodies. RESULTS: Twenty-one patients (60 %) carried HLA-DQ2 or DQ8, twice the frequency of the general population (P < 0.001). In particular DQ2 was overrepresented (P = 0.013). Gender, age, disease stage, histopathological grade, or multifocality of primary tumor did not differ between patients with DQ2 or DQ8 and patients with other HLA-DQ haplotypes. No patient in the study was diagnosed with celiac disease (latent or symptomatic) as anti-tTG antibodies were negative in all 35. CONCLUSION: HLA-DQ haplotypes associated with celiac disease are overrepresented also in patients with SI-NET, in particular HLA-DQ2.

Hemodialysis blood access flow rates can be estimated accurately from on-line dialysate urea measurements and the knowledge of effective dialyzer urea clearance.

Measurement of blood flow rate (Qa) is used to monitor arteriovenous fistulas and grafts that are used for hemodialysis blood access. Most Qa measurements use indicator dilution techniques to measure the recirculation that is induced by the reversal of hemodialysis blood lines. R plus the dialysis circuit flow (Qb) allows the calculation of Qa. The principle of needle reversal also can be used with a dialysate urea monitor (e.g., DQM 200 [Gambro]) without injection of diluent; the effect of the reversal on urea concentration is observed. Access blood water flow rate (Qaw) in relation to the effective clearance (K) is found from the urea concentrations in the dialysate with needles in the normal (Cn) and reverse (Cr) positions: K/Qaw = (Cn - Cr)/Cr. Qa is calculated by adjusting Qaw for hematocrit and protein. For testing of this theoretical relationship, 20 patients who were dialyzed on Integra (Hospal) and Centrysystem 3 (Cobe) machines that were fitted with DQM 200 were studied. During each treatment, lines were reversed and Qa was measured by ultrasound velocity dilution (Transonic HD01 monitor); at the same time, Cn and Cr were measured by DQM 200 and K was calculated. K1 was determined from a predialysis blood urea concentration (Cb), initial dialysate urea concentration (Cd), dialysate flow rate (Qd), and the relationship K x Cb = Qd x Cd (K1). K was determined separately from a conductivity step method using Diascan (Hospal) attached to Integra machines only (K2). With the use of K1, 127 comparisons were made; a correlation existed (r = 0.916), although Bland-Altman analysis showed that the dialysate urea method gave a mean value 5.3% +/- 15.3 (+/-SD) higher than that of Transonic (P < 0.001). With the use of K2, there also was a correlation of (r = 0.944; n = 63), and Bland-Altman testing showed an NS difference of +3.5% between the dialysate urea and Transonic methods. Qa can be estimated from on-line dialysate urea measurements that are taken before and after line reversal together with knowledge of K.