Comparison Between Total IgG, C1q, and C3d Single Antigen Bead Assays in Detecting Class I Complement-Binding Anti-HLA Antibodies.

BACKGROUND: Complement-binding donor-specific antibodies (DSAs) are associated with antibody-mediated rejection and allograft loss. Novel single antigen bead (SAB) assays-that is, complement component 1q (C1q) and complement component 3d (C3d) assays-have been developed to specifically detect complement-binding DSA, but it remains unclear whether these assays have an improved ability to detect complement-binding DSA as compared with using the total IgG SAB assay with a high mean fluorescence intensity (MFI) cutoff. The aim of this study was to compare the ability of the total IgG, C1q, and C3d SAB assays in detecting complement-binding anti-HLA antibodies. METHODS: Twenty sera known to have complement-binding anti-HLA antibodies (serologic class I HLA typing by complement-dependent cytotoxicity method) were tested with 3 different SAB assays: total IgG (undiluted and 1:8 dilution), C1q, and C3d. Serologic anti-HLA specificities were compared with those obtained by IgG, C1q, and C3d SAB assays. RESULTS: IgG SAB was more sensitive in detecting complement-binding antibodies (sensitivity 24 of 24 = 1, odds ratio infinity). Pearson correlation showed the association between (1) C1q and IgG SAB assays (cutoff C1q SAB 1000 MFI, cutoff IgG SAB 5000 MFI: r = 0.347, P < .0001) and (2) C3d and IgG SAB assays (cutoff 500 MFI C3d SAB, 5000 MFI for IgG SAB: r = -0.173, P = .279). CONCLUSIONS: For class I anti-HLA antibodies, IgG SAB (cutoff MFI > 5000) was more sensitive in detecting complement-binding antibodies when compared with C1q and C3d SAB assays.

Measurement of endothelial dysfunction via peripheral arterial tonometry predicts vasculogenic erectile dysfunction.

Endothelial cell dysfunction is associated with cardiovascular disease and vasculogenic erectile dysfunction (ED). Measured via peripheral artery tonometry (PAT), endothelial dysfunction in the penis is an independent predictor of future cardiovascular events. The aim of the study was to determine whether measurement of endothelial dysfunction differentiates men with vasculogenic ED identified by duplex ultrasound from those without. A total of 142 men were retrospectively assessed using patient history, penile duplex ultrasonography (US) and PAT (EndoPAT 2000). ED was self-reported and identified on history. Vasculogenic ED was identified in men who exhibited a peak systolic velocity (PSV) of ⩽ 25 cm s(-1) at 15 min following vasodilator injection. The reactive hyperemia index (RHI), a measurement of endothelial dysfunction in medium/small arteries, and the augmentation index (AI), a measurement of arterial stiffness, were recorded via PAT. Penile duplex US was used to categorize men into those with ED (n = 111) and those without ED (n = 31). The cohort with ED had a PSV of 21 ± 1 cm s(-1) (left cavernous artery) and 22 ± 1 cm s(-1) (right cavernous artery). The control group without ED had values of 39 ± 2 cm s(-1) (left) and 39 ± 2 cm s(-1) (right). Given the potential for altered endothelial function in diabetes mellitus, we confirmed that hemoglobin A1c, urinary microalbumin and vibration pulse threshold were not different in men with vasculogenic ED and those without. RHI in patients with ED (1.85 ± 0.06) was significantly decreased compared to controls (2.15 ± 0.2) (P<0.05). The AI was unchanged when examined in isolation, and when standardized to heart rate. Measurement of endothelial function with EndoPAT differentiates men with vasculogenic ED from those without. RHI could be used as a non-invasive surrogate in the assessment of vasculogenic ED and to identify those patients with higher cardiovascular risk.

The measurement of schizophrenic conceptualization using a Spanish translation of the Whitaker Index of Schizophrenic Thinking.

The Spanish translation of Form A of the Whitaker Index of Schizophrenic Thinking (WIST) was administered to 50 schizophrenic (25 acute; 25 chronic) and 50 (25 = depressives; 25 = normals) nonschizophrenic residents of the Commonwealth of Puerto Rico. Results suggest that this translation effectively discriminated between schizophrenics and non-schizophrenics on the WIST total score, time, and index. A cut-off of 25 on the WIST index correctly classified 98% of the schizophrenic volunteers.

Oral theophylline disposition in cystic fibrosis.

Theophylline absorption and disposition of CF patients have not been systematically studied. To evaluate these factors in CF subjects, seven CF patients were fasted overnight and administered a dose of aminophylline liquid equivalent to 4 mg/kg of anhydrous theophylline. Liver function tests (SGOT, GGT, alkaline phosphatase) were normal in all seven patients. maximum serum theophylline concentrations occurred between 30 and 60 minutes post-dose in all subjects and ranged from 4.8 to 8.6 mcg/ml. These values are similar to those reported in non-CF subjects for a single 4 mg/kg oral dose. The mean serum half-life of 3.5 hours with a range of 1.2 to 5.0 hours is similar to that reported in non-CF populations. The authors conclude that theophylline elimination (half-lives) in CF patients with normal liver function is similar to those of normal and asthmatic patients. CF patients with clinical liver disease may have a decreased clearance and should be carefully monitored.

Effects of cigarette smoking on recall and categorization of written material.

Habitual smokers participated in an experiment assessing the effects of smoking or abstinence upon immediate and delayed memory of new and old (previously presented) words, as well as category clustering. 10 smokers showed significantly poorer immediate and delayed recall of old words and less clustering of words into categories on the delayed recall test.