Collision-induced dissociation mechanisms of protonated penta- and octa-glycine as revealed by chemical dynamics simulations

Spezia, R.,Lee, S.B.,Cho, A.,Song, K. Elsevier 2015 INTERNATIONAL JOURNAL OF MASS SPECTROMETRY Vol.392 No.-

In this work, we have studied the collision-induced dissociation (CID) of protonated penta- and octa-glycine (both with -COOH and -CONH<SUB>2</SUB> C-terminal groups) by means of chemical dynamics simulations using a QM+MM approach. For the QM potential, a semi-empirical Hamiltonian (PM3) was employed. Simulations have shown that the full a<SUB>n</SUB><SUP>+</SUP> and b<SUB>n</SUB><SUP>+</SUP> series of fragments can be obtained. A detailed analysis of trajectories permitted to elucidate the mechanisms connecting reactants and products. In particular, both direct bond breaking and proton transfer initiated fragmentation pathways were observed. The two mechanisms are correlated with the way energy flows (or does not) through the modes after collision and before fragmentation. This study points out the importance of considering both mechanisms when modeling and studying fragmentation pathways of complex molecular systems.

Collision induced dissociation of doubly-charged ions: Coulomb explosion <i>vs.</i> neutral loss in [Ca(urea)]²⁺ gas phase unimolecular reactivity <i>via</i> chemical dynamics simulations

Spezia, Riccardo,Cimas, Alvaro,Gaigeot, Marie-Pierre,Salpin, Jean-Yves,Song, Kihyung,Hase, William L. The Royal Society of Chemistry 2012 Physical chemistry chemical physics Vol.14 No.33

<P>In this paper we report different theoretical approaches to study the gas-phase unimolecular dissociation of the doubly-charged cation [Ca(urea)]<SUP>2+</SUP>, in order to rationalize recent experimental findings. Quantum mechanical plus molecular mechanical (QM/MM) direct chemical dynamics simulations were used to investigate collision induced dissociation (CID) and rotational–vibrational energy transfer for Ar + [Ca(urea)]<SUP>2+</SUP> collisions. For the picosecond time-domain of the simulations, both neutral loss and Coulomb explosion reactions were found and the differences in their mechanisms elucidated. The loss of neutral urea subsequent to collision with Ar occurs <I>via</I> a shattering mechanism, while the formation of two singly-charged cations follows statistical (or almost statistical) dynamics. Vibrational–rotational energy transfer efficiencies obtained for trajectories that do not dissociate during the trajectory integration were used in conjunction with RRKM rate constants to approximate dissociation pathways assuming complete intramolecular vibrational energy redistribution (IVR) and statistical dynamics. This statistical limit predicts, as expected, that at long time the most stable species on the potential energy surface (PES) dominate. These results, coupled with experimental CID from which both neutral loss and Coulomb explosion products were obtained, show that the gas phase dissociation of this ion occurs by multiple mechanisms leading to different products and that reactivity on the complicated PES is dynamically complex.</P> <P>Graphic Abstract</P><P>Chemical dynamics and statistical analysis differentiate reaction pathway kinetics between neutral loss and Coulomb explosion in unimolecular [Ca(urea)]<SUP>2+</SUP> dissociation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2cp41379e'> </P>

Isoflurane and the Analgesic Effect of Acupuncture and Electroacupuncture in an Animal Model of Neuropathic Pain

Lauren N. Spezia Adachi,Rafael Vercelino,Carla de Oliveira,Vanessa L. Scarabelot,Andressa de Souza,Liciane F. Medeiros,Stefania G. Cioato,Wolnei Caumo,Iraci L.S. Torres 사단법인약침학회 2018 Journal of Acupuncture & Meridian Studies Vol.11 No.3

The present study aimed to determine whether isoflurane interferes with the analgesiceffects of acupuncture (Ac) and electroacupuncture (EA), using a neuropathic pain(NP) rat model. In total, 140 male Wistar rats were used; isoflurane-induced nociceptiveresponse was evaluated using the von Frey test, serum calcium-binding protein b (S100b)levels and nerve growth factor (NGF) levels in the left sciatic nerve. The NP model wasinduced by chronic constriction injury of the sciatic nerve at 14 days after surgery. Treatment was initiated after NP induction with or without isoflurane anesthesia (20 min/day/8 days). The von Frey test was performed at baseline, 14 days postoperatively, andimmediately, 24 h, and 48 h after the last treatment. Results of the nociceptive test andthree-way analysis of variance were analyzed by generalized estimating equations, theBonferroni test, followed by StudenteNewmaneKeuls or Fisher’s least significant differencetests for comparing biochemical parameters (significance defined as p 0.05). Atbaseline, no difference was noted in the nociceptive response threshold among allgroups. Fourteen days after surgery, compared with other groups, NP groups showed adecreased pain threshold, confirming establishment of NP. Ac and EA enhanced the mechanicalpain threshold immediately after the last session in the NP groups, without anesthesia. Isoflurane administration caused increased nociceptive threshold in all groups,and this effect persisted for 48 h after the last treatment. There was an interaction betweenthe independent variables: pain, treatments, and anesthesia in serum S100b levelsand NGF levels in the left sciatic nerve. Isoflurane enhanced the analgesic effects of Acand EA and altered serum S100b and left sciatic nerve NGF levels in rats with NP.

20 Things You Didn’t Know About Type 2 Diabetes in Emerging Adults :

Cha, EunSeok,Haw, Jeehea Sonya,Faulkner, Melissa Spezia ASPEN PUBLISHERS INC 2017 JOURNAL OF CARDIOVASCULAR NURSING Vol.32 No.4

Dietary Behaviors and Glucose Metabolism in Young Adults at Risk for Type 2 Diabetes

Cha, EunSeok,Paul, Sudeshna,Braxter, Betty J.,Umpierrez, Guillermo,Faulkner, Melissa Spezia SAGE Publications 2018 The Diabetes educator Vol.44 No.2

<P>Conclusion Findings are useful to develop age-specific nutrition guidelines to prevent early onset T2D in high-risk young adults.</P>

Fast-track surgery and telerehabilitation protocol in unicompartmental knee arthroplasty leads to superior outcomes when compared with the standard protocol: a propensity-matched pilot study

( Luca De Berardinis ),( Marco Senarighi ),( Carlo Ciccullo ),( Fabiana Forte ),( Marco Spezia ),( Antonio Pompilio Gigante ) 대한슬관절학회 2022 대한슬관절학회지 Vol.34 No.-

Background: Several strategies have been devised to reduce the length of stay after orthopedic surgery. Telerehabilitation has proved effective in functional outcomes after orthopedic procedures and is appreciated by patients. There is limited information on fast-track surgery and telerehabilitation protocols for unicompartmental knee arthroplasty (UKA). The purpose of this pilot study was to report and compare functional outcomes and satisfaction levels during first 12 months of recovery in patients who underwent UKA according to a fast-track and telerehabilitation protocol (G1) or standard surgery and rehabilitation program (G2). Methods: Data were retrospectively collected and reviewed for all elective UKAs from January 2018 to November 2019. A total of seven patients undergoing UKA according to the fast-track and telerehabilitation protocol were propensity score matched (1:3 ratio) to 21 patients undergoing standard surgery and rehabilitation. Patients were matched for age, sex, body mass index (BMI), and laterality. The Western Ontario and McMaster University (WOMAC) osteoarthritis index and range of motion (ROM) were collected pre- and postoperatively in both groups for 12 months. In addition, patient’ satisfaction was collected at 40 days. Results: The G1 group demonstrated significantly better outcomes in WOMAC index scores at 2, 15, and 40 days (p < 0.001, p < 0.001, p < 0.020, respectively) and a significantly greater knee ROM after surgery and at 2, 15, 40, and 12 months (p < 0.001, p < 0.001, p = 0.014, p < 0.001, p = 0.003, respectively). No patients in either group had postoperative complications. One patient was not completely satisfied in the G2, while no one in G1 reported not being completely satisfied (p = 1.000). Conclusions: This fast-track and telerehabilitation protocol after UKA can potentially be applied to patients as it is safe and effective. At 12-months follow-up, both groups reported favorable outcomes after UKA. However, the G1 score was better regarding WOMAC and ROM when compared with the propensity score-matched G2 program. A larger study is warranted to explore the role of fast-track and telerehabilitation in clinical and functional outcomes of UKA.