Persistence of Prolonged C-peptide Production in Type 1 Diabetes as Measured With an Ultrasensitive C-peptide Assay

Objective: To examine persistence of C-peptide production by ultrasensitive assay years after onset of type 1 diabetes and factors associated with preserving β-cell function. Research Design and Methods: Serum C-peptide levels, a marker of insulin production and surviving β-cells, were measured in human subjects (n = 182) by ultrasensitive assay, as was β-cell functioning. Twenty-two times more sensitive than standard assays, this assay’s lower detection limit is 1.5 pmol/L. Disease duration, age at onset, age, sex, and autoantibody titers were analyzed by regression analysis to determine their relationship to C-peptide production. Another group of four patients was serially studied for up to 20 weeks to examine C-peptide levels and functioning. Results: The ultrasensitive assay detected C-peptide in 10% of individuals 31–40 years after disease onset and with percentages higher at shorter duration. Levels as low as 2.8 ± 1.1 pmol/L responded to hyperglycemia with increased C-peptide production, indicating residual β-cell functioning. Several other analyses showed that β-cells, whose C-peptide production was formerly undetectable, were capable of functioning. Multivariate analysis found disease duration (β = −2.721; P = 0.005) and level of zinc transporter 8 autoantibodies (β = 0.127; P = 0.015) significantly associated with C-peptide production. Unexpectedly, onset at >40 years of age was associated with low C-peptide production, despite short disease duration. Conclusions: The ultrasensitive assay revealed that C-peptide production persists for decades after disease onset and remains functionally responsive. These findings suggest that patients with advanced disease, whose β-cell function was thought to have long ceased, may benefit from interventions to preserve β-cell function or to prevent complications

The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules

Beams of atoms and molecules are stalwart tools for spectroscopy and studies of collisional processes. The supersonic expansion technique can create cold beams of many species of atoms and molecules. However, the resulting beam is typically moving at a speed of 300-600 m/s in the lab frame, and for a large class of species has insufficient flux (i.e. brightness) for important applications. In contrast, buffer gas beams can be a superior method in many cases, producing cold and relatively slow molecules in the lab frame with high brightness and great versatility. There are basic differences between supersonic and buffer gas cooled beams regarding particular technological advantages and constraints. At present, it is clear that not all of the possible variations on the buffer gas method have been studied. In this review, we will present a survey of the current state of the art in buffer gas beams, and explore some of the possible future directions that these new methods might take

Reading and Commenting on Aristotle

Questo studio esamina brevemente la ricezione Bizantina della filosofia di Aristotele. Include uno studio sui manoscritti principali del corpus aristotelicum e dei principali lettori di Aristotele

Classical scholarship: the Byzantine contribution

Discusses the effect that Byzantine work has had on our perception of ancient Greek language and literature (especially Homer and drama)

Trials of Philosophers and Theologians under the Komnenoi

Questo articolo studia i processi per eterodossia a Bisanzio tra i secoli XI e XI