Enzymes are proteins that accelerate intracellular chemical reactions often by factors of 10(5) - 10(12)s(-1). We propose the structure and function of enzymes represent the thermodynamic expression ...of heritable information encoded in DNA with post-translational modifications that reflect intra- and extra-cellular environmental inputs. The 3 dimensional shape of the protein, determined by the genetically-specified amino acid sequence and post translational modifications, permits geometric interactions with substrate molecules traditionally described by the key-lock best fit model. Here we apply Kullback-Leibler (K-L) divergence as metric of this geometric "fit" and the information content of the interactions. When the K-L 'distance' between interspersed substrate p(n) and enzyme r(n) positions is minimized, the information state, reaction probability, and reaction rate are maximized. The latter obeys the Arrhenius equation, which we show can be derived from the geometrical principle of minimum K-L distance. The derivation is first limited to optimum substrate positions for fixed sets of enzyme positions. However, maximally improving the key/lock fit, called 'induced fit,' requires both sets of positions to be varied optimally. We demonstrate this permits and is maximally efficient if the key and lock particles p(n), r(n) are quantum entangled because the level of entanglement obeys the same minimized value of the Kullback-Leibler distance that occurs when all p(n) approximate to r(n). This implies interchanges p(n) reversible arrow br(n) randomly taking place during a reaction successively improves key/lock fits, reducing the activation energy E-a and increasing the reaction rate k. Our results demonstrate the summation of heritable and environmental information that determines the enzyme spatial configuration, by decreasing the K-L divergence, is converted to thermodynamic work by reducing Ea and increasing k of intracellular reactions. Macroscopically, enzyme information increases the order in living systems, similar to the Maxwell demon gedanken, by selectively accelerating specific reaction thus generating both spatial and temporal concentration gradients.
Blood oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) is commonly performed using 2D single-shot echo-planar imaging (EPI). However, recent studies have suggested that ...3D multi-shot sequences such as PRESTO may offer comparable BOLD contrast-to-noise ratio with increased volume coverage and decreased geometric distortions. A four-way comparison was performed between 2D and 3D acquisition sequences at two inplane resolutions at 7 Tesla. The quality of fMRI data was evaluated via independent and unbiased metrics of prediction and reproducibility using NPAIRS. Results show that although high-resolution EPI had the highest overall z-scores, PRESTO had higher z-scores than EPI at a matched in-plane resolution. Activation maps constructed with data from EPI and PRESTO show very good agreement in both sensitivity and specificity.
Ten patients received lymphoblastoid alpha-interferon (Wellferon) in a crossover study so that Wellferon and standard microsurgical laryngeal laser therapy could be compared to laser therapy alone. ...Wellferon was administered initially at an intravenous high dose of 15 megaunits/m2 for 5 days followed by a daily dose of 2 megaunits/m2 subcutaneously for 6 months. Dosage was adjusted according to predefined toxicity. One patient was withdrawn from the study. Of the others, all but one received over 75% of the planned total dose. At follow-up of the nine assessable patients, complete remission was achieved in two of them, partial remission in four, and no response in the remainder. The two complete remissions were sustained for 2 years, but the four partial remissions were not sustained. Thus, a role for alpha-interferon in the kind of regimen used here remains to be established.
Zenker's diverticula are esophageal outpouchings in the region of the cricopharyngeus which typically grow in a posterolateral and inferior direction and can cause esophageal compression if the ...diverticulum is large enough. We describe a patient in whom a Zenker's diverticulum expanded posteriorly and superiorly so that it was positioned in the posterior pharyngeal space, causing both esophageal and tracheal narrowing.
PDF
