Time-resolved spectroscopy studies of the photodeprotection reactions of p-hydroxyphenacyl ester phototrigger compounds

Ultrafast time-resolved spectroscopy and time-resolved resonance Raman spectroscopy experimental results in the picoseocond timescales are reported for selected p-hydroxyphenacyl (pHP) ester phototrigger compounds. The results better elucidate the photodeprotection and rearrangement reactions of these important phototriggers and an overall mechanism is proposed for these reactions based on the time-resolved spectroscopy data presented here. This work indicates that site-specific, concerted solvation of the hydroxy proton and phosphate-leaving anion group through their respective intermolecular H-bonding with solvent water molecules promotes the photodeprotection reaction.published_or_final_versio

Properties of small molecular drug loading and diffusion in a fluorinated PEG hydrogel studied by ^1H molecular diffusion NMR and ^(19)F spin diffusion NMR

R_f-PEG (fluoroalkyl double-ended poly(ethylene glycol)) hydrogel is potentially useful as a drug delivery depot due to its advanced properties of sol–gel two-phase coexistence and low surface erosion. In this study, ^1H molecular diffusion nuclear magnetic resonance (NMR) and ^(19)F spin diffusion NMR were used to probe the drug loading and diffusion properties of the R_f-PEG hydrogel for small anticancer drugs, 5-fluorouracil (FU) and its hydrophobic analog, 1,3-dimethyl-5-fluorouracil (DMFU). It was found that FU has a larger apparent diffusion coefficient than that of DMFU, and the diffusion of the latter was more hindered. The result of ^(19)F spin diffusion NMR for the corresponding freeze-dried samples indicates that a larger portion of DMFU resided in the R_f core/IPDU intermediate-layer region (where IPDU refers to isophorone diurethane, as a linker to interconnect the R_f group and the PEG chain) than that of FU while the opposite is true in the PEG–water phase. To understand the experimental data, a diffusion model was proposed to include: (1) hindered diffusion of the drug molecules in the R_f core/IPDU-intermediate-layer region; (2) relatively free diffusion of the drug molecules in the PEG-water phase (or region); and (3) diffusive exchange of the probe molecules between the above two regions. This study also shows that molecular diffusion NMR combined with spin diffusion NMR is useful in studying the drug loading and diffusion properties in hydrogels for the purpose of drug delivery applications

Arterial oxygen content is precisely maintained by graded erythrocytotic responses in settings of high/normal serum iron levels, and predicts exercise capacity: an observational study of hypoxaemic patients with pulmonary arteriovenous malformations.

Oxygen, haemoglobin and cardiac output are integrated components of oxygen transport: each gram of haemoglobin transports 1.34 mls of oxygen in the blood. Low arterial partial pressure of oxygen (PaO2), and haemoglobin saturation (SaO2), are the indices used in clinical assessments, and usually result from low inspired oxygen concentrations, or alveolar/airways disease. Our objective was to examine low blood oxygen/haemoglobin relationships in chronically compensated states without concurrent hypoxic pulmonary vasoreactivity.165 consecutive unselected patients with pulmonary arteriovenous malformations were studied, in 98 cases, pre/post embolisation treatment. 159 (96%) had hereditary haemorrhagic telangiectasia. Arterial oxygen content was calculated by SaO2 x haemoglobin x 1.34/100.There was wide variation in SaO2 on air (78.5-99, median 95)% but due to secondary erythrocytosis and resultant polycythaemia, SaO2 explained only 0.1% of the variance in arterial oxygen content per unit blood volume. Secondary erythrocytosis was achievable with low iron stores, but only if serum iron was high-normal: Low serum iron levels were associated with reduced haemoglobin per erythrocyte, and overall arterial oxygen content was lower in iron deficient patients (median 16.0 [IQR 14.9, 17.4]mls/dL compared to 18.8 [IQR 17.4, 20.1]mls/dL, p<0.0001). Exercise tolerance appeared unrelated to SaO2 but was significantly worse in patients with lower oxygen content (p<0.0001). A pre-defined athletic group had higher Hb:SaO2 and serum iron:ferritin ratios than non-athletes with normal exercise capacity. PAVM embolisation increased SaO2, but arterial oxygen content was precisely restored by a subsequent fall in haemoglobin: 86 (87.8%) patients reported no change in exercise tolerance at post-embolisation follow-up.Haemoglobin and oxygen measurements in isolation do not indicate the more physiologically relevant oxygen content per unit blood volume. This can be maintained for SaO2 ≥78.5%, and resets to the same arterial oxygen content after correction of hypoxaemia. Serum iron concentrations, not ferritin, seem to predict more successful polycythaemic responses

Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice

Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA

A Pair of Dopamine Neurons Target the D1-Like Dopamine Receptor DopR in the Central Complex to Promote Ethanol-Stimulated Locomotion in Drosophila

Dopamine is a mediator of the stimulant properties of drugs of abuse, including ethanol, in mammals and in the fruit fly Drosophila. The neural substrates for the stimulant actions of ethanol in flies are not known. We show that a subset of dopamine neurons and their targets, through the action of the D1-like dopamine receptor DopR, promote locomotor activation in response to acute ethanol exposure. A bilateral pair of dopaminergic neurons in the fly brain mediates the enhanced locomotor activity induced by ethanol exposure, and promotes locomotion when directly activated. These neurons project to the central complex ellipsoid body, a structure implicated in regulating motor behaviors. Ellipsoid body neurons are required for ethanol-induced locomotor activity and they express DopR. Elimination of DopR blunts the locomotor activating effects of ethanol, and this behavior can be restored by selective expression of DopR in the ellipsoid body. These data tie the activity of defined dopamine neurons to D1-like DopR-expressing neurons to form a neural circuit that governs acute responding to ethanol

The systematic guideline review: method, rationale, and test on chronic heart failure

Background: Evidence-based guidelines have the potential to improve healthcare. However, their de-novo-development requires substantial resources-especially for complex conditions, and adaptation may be biased by contextually influenced recommendations in source guidelines. In this paper we describe a new approach to guideline development-the systematic guideline review method (SGR), and its application in the development of an evidence-based guideline for family physicians on chronic heart failure (CHF). Methods: A systematic search for guidelines was carried out. Evidence-based guidelines on CHF management in adults in ambulatory care published in English or German between the years 2000 and 2004 were included. Guidelines on acute or right heart failure were excluded. Eligibility was assessed by two reviewers, methodological quality of selected guidelines was appraised using the AGREE instrument, and a framework of relevant clinical questions for diagnostics and treatment was derived. Data were extracted into evidence tables, systematically compared by means of a consistency analysis and synthesized in a preliminary draft. Most relevant primary sources were re-assessed to verify the cited evidence. Evidence and recommendations were summarized in a draft guideline. Results: Of 16 included guidelines five were of good quality. A total of 35 recommendations were systematically compared: 25/35 were consistent, 9/35 inconsistent, and 1/35 un-rateable (derived from a single guideline). Of the 25 consistencies, 14 were based on consensus, seven on evidence and four differed in grading. Major inconsistencies were found in 3/9 of the inconsistent recommendations. We re-evaluated the evidence for 17 recommendations (evidence-based, differing evidence levels and minor inconsistencies) - the majority was congruent. Incongruity was found where the stated evidence could not be verified in the cited primary sources, or where the evaluation in the source guidelines focused on treatment benefits and underestimated the risks. The draft guideline was completed in 8.5 man-months. The main limitation to this study was the lack of a second reviewer. Conclusion: The systematic guideline review including framework development, consistency analysis and validation is an effective, valid, and resource saving-approach to the development of evidence-based guidelines

Lack of chart reminder effectiveness on family medicine resident JNC-VI and NCEP III guideline knowledge and attitudes

BACKGROUND: The literature demonstrates that medical residents and practicing physicians have an attitudinal-behavioral discordance concerning their positive attitudes towards clinical practice guidelines (CPG), and the implementation of these guidelines into clinical practice patterns. METHODS: A pilot study was performed to determine if change in a previously identified CPG compliance factor (accessibility) would produce a significant increase in family medicine resident knowledge and attitude toward the guidelines. The primary study intervention involved placing a summary of the Sixth Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VI) and the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (NCEP III) CPGs in all patient (>18 yr.) charts for a period of three months. The JNC VI and NCEP III CPGs were also distributed to each Wayne State family medicine resident, and a copy of each CPG was placed in the preceptor's area of the involved clinics. Identical pre- and post- intervention questionnaires were administered to all residents concerning CPG knowledge and attitude. RESULTS: Post-intervention analysis failed to demonstrate a significant difference in CPG knowledge. A stastically significant post-intervention difference was found in only on attitude question. The barriers to CPG compliance were identified as 1) lack of CPG instruction; 2) lack of critical appraisal ability; 3) insufficient time; 4) lack of CPG accessibility; and 5) lack of faculty modeling. CONCLUSION: This study demonstrated no significant post intervention changes in CPG knowledge, and only one question that reflected attitude change. Wider resident access to dedicated clinic time, increased faculty modeling, and the implementation of an electronic record/reminder system that uses a team-based approach are compliance factors that should be considered for further investigation. The interpretation of CPG non-compliance will benefit from a causal matrix focused on physician knowledge, attitudes, and behavior. Recent findings in resident knowledge-behavior discordance may direct the future investigation of physician CPG non-compliance away from generalized barrier research, and toward the development of information that maximizes the sense of individual practitioner urgency and certainty

Zanubrutinib for the treatment of relapsed or refractory mantle cell lymphoma

Abstract Zanubrutinib, a highly selective Bruton tyrosine kinase inhibitor, was evaluated in a phase 1/2 study in patients with various B-cell malignancies. In the subgroup of patients with relapsed/refractory (R/R) mantle cell lymphoma (MCL), zanubrutinib was administered as 160 mg twice daily (n = 14), 320 mg once daily (n = 18), or ≤160 mg total dose (n = 5). Herein, we report results for patients receiving a total daily dose of 320 mg (N = 32). Median study follow-up was 18.8 months. Eighteen patients discontinued treatment, 10 because of progressive disease and 8 because of adverse events (AEs); 1 AE (peripheral edema) was considered to be related to zanubrutinib treatment. The most common AEs were diarrhea (43.8%), contusion (37.5%), constipation (31.3%), and upper respiratory tract infection (31.3%). Infection was the most commonly reported AE of interest (18.8% of patients experienced grade ≥3 infection). At least 1 AE of grade ≥3 was reported in 59.4% of patients; grade ≥3 AEs that were reported in &amp;gt;2 patients were anemia (12.5%), pneumonia (9.4%), and myalgia (9.4%). Overall response rate was 84%, with 25% achieving a complete response. Median duration of response was 18.5 months. Median progression-free survival (PFS) was 21.1 months. Zanubrutinib was well tolerated and demonstrated activity in patients with R/R MCL. The trial is registered at www.clinicaltrials.gov as #NCT02343120.</jats:p

Visualization of Allostery in P-Selectin Lectin Domain Using MD Simulations

Allostery of P-selectin lectin (Lec) domain followed by an epithelial growth factor (EGF)-like domain is essential for its biological functionality, but the underlying pathways have not been well understood. Here the molecular dynamics simulations were performed on the crystallized structures to visualize the dynamic conformational change for state 1 (S1) or state 2 (S2) Lec domain with respective bent (B) or extended (E) EGF orientation. Simulations illustrated that both S1 and S2 conformations were unable to switch from one to another directly. Instead, a novel S1' conformation was observed from S1 when crystallized B-S1 or reconstructed “E-S1” structure was employed, which was superposed well with that of equilibrated S1 Lec domain alone. It was also indicated that the corresponding allosteric pathway from S1 to S1' conformation started with the separation between residues Q30 and K67 and terminated with the release of residue N87 from residue C109. These results provided an insight into understanding the structural transition and the structure-function relationship of P-selectin allostery

An unbiased survey of 500 nearby stars for debris disks: A JCMT legacy program

We present the scientific motivation and observing plan for an upcoming detection survey for debris disks using the James Clerk Maxwell Telescope. The SCUBA‐2 Unbiased Nearby Stars (SUNS) survey will observe 500 nearby main‐sequence and subgiant stars (100 of each of the A, F, G, K, and M spectral classes) to the 850 μm extragalactic confusion limit to search for evidence of submillimeter excess, an indication of circumstellar material. The survey distance boundaries are 8.6, 16.5, 22, 25, and 45 pc for M, K, G, F, and A stars, respectively, and all targets lie between the declinations of −40° to 80°. In this survey, no star will be rejected based on its inherent properties: binarity, presence of planetary companions, spectral type, or age. The survey will commence in late 2007 and will be executed over 390 hr, reaching 90% completion within 2 years. This will be the first unbiased survey for debris disks since the Infrared Astronomical Satellite. We expect to detect ~125 debris disks, including ~50 cold disks not detectable in current shorter wavelength surveys. To fully exploit the order of magnitude increase in debris disks detected in the submillimeter, a substantial amount of complementary data will be required, especially at shorter wavelengths, to constrain the temperatures and masses of discovered disks. High‐resolution studies will likely be required to resolve many of the disks. Therefore, these systems will be the focus of future observational studies using a variety of observatories, including Herschel, ALMA, and JWST, to characterize their physical properties. For nondetected systems, this survey will set constraints (upper limits) on the amount of circumstellar dust, of typically 200 times the Kuiper Belt mass, but as low as 10 times the Kuiper Belt mass for the nearest stars in the sample (≈2 pc)