Structural characterization of CD6: properties of two distinct epitopes involved in T cell activation

Studies from our laboratory have shown that anti-T12, a mAb which recognizes CD6, is a macrophage-dependent mitogen for human T cells and can augment T cell autoreactivity in vitro. To obtain additional information regarding the potential biological role of CD6 we sought to further characterize its biochemical properties. The CD6 molecule on 125I-surface-labeled T cells and by Western blot analysis was a monomer of mol. wt 130,000 under reducing conditions and mol. wt 117,000 under non-reducing conditions, suggesting the presence of intrachain disulfide bonds. The polypeptide contains a protease sensitive site. In activated T cells, the protein was serine phosphorylated. Analysis of biosynthetically labeled CD6 in the presence of tunicamycin revealed a reduction in mol. wt from 130,000 to 100,000, indicating that the polypeptide is extensively N-glycosylated. The mAb, anti-2H1, had been shown to activate T cells in combination with PMA or the anti-T11(3) mAb but, unlike anti-T12, not in the presence of macrophages alone. The present studies demonstrate by sequential immunoprecipitation that these two mAbs recognize the same polypeptide. However, Western blot analysis and indirect immunofluorescence cross-blocking studies demonstrate that the two mAbs recognize different determinants on CD6. Anti-T12 recognizes an epitope that is present only under non-reducing/non-denaturing conditions, while anti-2H1 recognizes an epitope that is also preserved under reducing/denaturing conditions. A direct comparison of activation properties of the mAbs confirmed that anti-T12 was optimally mitogenic in the presence of macrophages but not PMA, while, conversely, anti-2H1 was optimally mitogenic in combination with PMA but not macrophages, suggesting that the differences in epitope specificity may account for the distinct activation properties of each mAb. Taken together, the structural and functional data strongly suggest that the CD6 membrane glycoprotein may function as a physiologically important receptor structure on human T lymphocytes.     

An enhanced chemiluminescent enzyme immunoassay for follicle stimulating hormone

An enhanced chemiluminescent enzyme immunoassay for serum follicle stimulating hormone is described which involves sequential reaction of anti-follicle stimulating hormone antibody immobilised to the inside surface of an opaque microtitre plate with sample, monoclonal anti-alpha thyroid stimulating hormone antibody, and an anti-mouse IgG - horseradish peroxidase conjungate. Bound peroxidase activity was measured using a p-hydroxycinnamic acid enhanced chemiluminescent luminol-hydrogen peroxide reaction. The assay was sensitive (detection limit 0.01 mU/well) precise (intra-assay precision 2.5-8.1%, inter-assay precision 6.7-11.9%) and results obtained with this assay and a competitive radioimmunoassay were in good agreement (correlation coefficient 0.98).     

Congenital tracheal stenosis in Pfeiffer syndrome

We report an infant with Pfeiffer syndrome (acrocephalosyndactyly type V) and a solid cartilaginous trachea lacking rings. This airway abnormality has been reported in a child with Crouzon syndrome but has not been described in Pfeiffer syndrome.     

Otoacoustic emissions as a screening test for hearing impairment in children recovering from acute bacterial meningitis

OBJECTIVES: To study the efficacy of otoacoustic emissions (OAEs) as a screening test for hearing impairment in children with acute bacterial meningitis. Hearing tests were performed before discharge from the hospital in an attempt to improve coverage and avoid delays in the diagnosis of postmeningitic hearing loss. METHODS: Children with bacterial meningitis were recruited from 21 centers. In the 48 hours before discharge from the hospital, all patients underwent a thorough audiologic assessment consisting of transient evoked OAEs, auditory brainstem responses (ABRs), otoscopy, and tympanometry. Hearing loss was defined as ABR threshold >/=30 dB. The results of OAE screening were compared with the gold standard of ABR threshold. RESULTS: Of 124 children recruited, we were able to perform both OAEs and ABRs on 110 children. Seven (6.3%) of the 110 children had ABR threshold >/=30 dB; 2 had sensorineural hearing loss and 5 had conductive hearing loss. At follow-up, hearing loss persisted in both cases of sensorineural hearing loss and no new cases were identified. All 7 children with hearing loss failed the OAE screening test. Ninety-four children with normal hearing thresholds passed the test, and 9 failed. Thus, the screening test had a sensitivity of 1.00 (95% confidence interval, 0.59 to 1.00), a specificity of 0.91 (0.85 to 0.97), a positive predictive value of 0. 44 (0.20 to 0.70), and a negative predictive value of 1.00 (0.96 to 1.00). CONCLUSIONS: OAE screening in children recovering from meningitis was found to be feasible and effective. The test was highly sensitive and reasonably specific. Inpatient OAE screening should allow early diagnosis of postmeningitic hearing loss and prompt auditory rehabilitation.     

Gemcitabine plus carboplatin versus mitomycin, ifosfamide, and cisplatin in patients with stage IIIB or IV non-small-cell lung cancer: a phase III randomized study of the London Lung Cancer Group.

PURPOSE: This phase III randomized trial compared two chemotherapy regimens, gemcitabine plus carboplatin and mitomycin, ifosfamide, and cisplatin, in chemotherapy-naive patients with advanced non-small-cell lung cancer (NSCLC). The regimens were compared with regard to effects on survival, response rates, toxicity, and quality of life. PATIENTS AND METHODS: Eligible patients had previously untreated stage IIIB or IV NSCLC suitable for cisplatin-based chemotherapy. Randomly assigned patients were to receive four cycles, each at 3-week intervals, of carboplatin area under the curve of 5 on day 1 plus gemcitabine 1,200 mg/m(2) on days 1 and 8 (GCa) or mitomycin 6 mg/m(2), ifosfamide 3g/m(2), and cisplatin 50 mg/m(2) on day 1 (MIC). RESULTS: Between February 1999 and August 2001, 422 patients (GCa, n = 212; MIC, n = 210) were randomly assigned in the United Kingdom. The majority of patients received the intended four cycles (GCa, 64%; MIC, 61%). There was a significant survival advantage for GCa compared with MIC (hazard ratio, 0.76; 95% CI, 0.61 to 0. 93; P = .008). Median survival was 10 months with GCa and 7.6 months with MIC (difference, 2.4 months; 95% CI, 1.0 to 4.0), and 1-year survival was 40% with GCa and 30% with MIC (difference, 10%; 95% CI, 3% to 18%). Overall response rates were similar (42% for GCa v 41% for MIC; P = .84). More thrombocytopenia occurred with GCa (P = .03), but this was not associated with increased hospital admission or fatality. GCa caused less nausea, vomiting, constipation, and alopecia and was associated with fewer admissions for administration and better quality of life. CONCLUSION: In patients with advanced NSCLC, GCa chemotherapy was shown to be a better-tolerated treatment that conferred a survival advantage over MIC.     

The past,present, and future of sleep measurement in mild cognitive impairment and early dementia—towards a core outcome set: a scoping review

Study ObjectivesSleep abnormalities emerge early in dementia and may accelerate cognitive decline. Their accurate characterization may facilitate earlier clinical identification of dementia and allow for assessment of sleep intervention efficacy. This scoping review determines how sleep is currently measured and reported in Mild Cognitive Impairment (MCI) and early dementia, as a basis for future core outcome alignment.MethodsThis review follows the PRISMA Guidelines for Scoping Reviews. CINAHL, Embase, Medline, Psychinfo, and British Nursing Index databases were searched from inception—March 12, 2021. Included studies had participants diagnosed with MCI and early dementia and reported on sleep as a key objective/ outcome measure.ResultsNineteen thousand five hundred and ninety-six titles were returned following duplicate removal with 188 studies [N] included in final analysis. Sleep data was reported on 17 139 unique, diagnostically diverse participants (n). “Unspecified MCI” was the most common diagnosis amongst patients with MCI (n = 5003, 60.6%). Despite technological advances, sleep was measured most commonly by validated questionnaires (n = 12 586, N = 131). Fewer participants underwent polysomnography (PSG) (n = 3492, N = 88) and actigraphy (n = 3359, N = 38) with little adoption of non-PSG electroencephalograms (EEG) (n = 74, N = 3). Sleep outcome parameters were reported heterogeneously. 62/165 (37.6%) were described only once in the literature (33/60 (60%) in interventional studies). There was underrepresentation of circadian (n = 725, N = 25) and micro-architectural (n = 360, N = 12) sleep parameters.ConclusionsAlongside under-researched areas, there is a need for more detailed diagnostic characterization. Due to outcome heterogeneity, we advocate for international consensus on core sleep outcome parameters to support causal inference and comparison of therapeutic sleep interventions.