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Majhi J, Matsuo B, Oh H, Kim S, Sharique M, Molander GA. Photochemical Deoxygenative Hydroalkylation of Unactivated Alkenes Promoted by a Nucleophilic Organocatalyst. Angew Chem Int Ed Engl 2024; 63:e202317190. [PMID: 38109703 DOI: 10.1002/anie.202317190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 12/20/2023]
Abstract
The direct utilization of simple and abundant feedstocks in carbon-carbon bond-forming reactions to embellish sp3 -enriched chemical space is highly desirable. Herein, we report a novel photochemical deoxygenative hydroalkylation of unactivated alkenes with readily available carboxylic acid derivatives. The reaction displays broad functional group tolerance, accommodating carboxylic acid-, alcohol-, ester-, ketone-, amide-, silane-, and boronic ester groups, as well as nitrile-containing substrates. The reaction is operationally simple, mild, and water-tolerant, and can be carried out on multigram-scale, which highlights the utility of the method to prepare value-added compounds in a practical and scalable manner. The synthetic application of the developed method is further exemplified through the synthesis of suberanilic acid, a precursor of vorinostat, a drug used for the treatment of cutaneous T-cell lymphoma. A novel mechanistic approach was identified using thiol as a nucleophilic catalyst, which forms a key intermediate for this transformation. Furthermore, electrochemical studies, quantum yield, and mechanistic experiments were conducted to support a proposed catalytic cycle for the transformation.
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Affiliation(s)
- Jadab Majhi
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
| | - Bianca Matsuo
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
| | - Hyunjung Oh
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
| | - Saegun Kim
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
| | - Mohammed Sharique
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
| | - Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, 19104-6323, Philadelphia, PA, USA
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Saha S, Chopra A, Kamath SU, Kashyap NN. Can acid produced from probiotic bacteria alter the surface roughness, microhardness, and elemental composition of enamel? An in vitro study. Odontology 2023; 111:929-941. [PMID: 36995435 PMCID: PMC10492682 DOI: 10.1007/s10266-023-00804-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 03/14/2023] [Indexed: 03/31/2023]
Abstract
Probiotics are live microorganisms that upon administration in adequate amounts provide various health benefits to the host. Probiotics are "lactic acid-producing bacteria" as they release large amounts of organic acids, particularly lactic acids, in their surrounding environment. Although the acids produced by probiotics are beneficial for gastrointestinal and vaginal health, the acidogenic nature of probiotics has raised concerns among dental professionals, especially concerning their effect on the enamel and dentin. Previous studies have found that probiotics can lower the pH of the saliva and cause essential elements like Calcium and Phosphorus to leach from the enamel. This can alter the surface topography of enamel and increase the risk of enamel defects. Studies have also noted that probiotic bacteria can replace cariogenic bacteria and lower the risk of tooth decay. However, the effect of acid produced by probiotics on the enamel surface remains unclear. Hence, the present study aims to evaluate the effect of probiotics on the surface roughness, microhardness, and elemental composition of enamel compared to 0.1 M Lactic acid (demineralizing agent). Twenty enamel sections were randomly divided into groups and subjected to a pH cycling model using a probiotic suspension and 0.1 M lactic acid. The changes in the surface roughness, microhardness, surface morphology, and elemental composition of the enamel with regard to Carbon, Oxygen, Sodium, Hydrogen, Magnesium, Phosphorus, Fluoride, Chlorine, and Calcium of the enamel were evaluated before and after the emersion in both the groups. The results showed a significant increase in the mean surface roughness in the probiotic group before and after the exposure. The microhardness of the enamel decreased along with altered arrangement of the enamel prisms, increased striations, scratch marks, and pitting after exposure to the probiotic group. A decrease in the atomic/weight% for Calcium, Phosphorous, Fluoride, Aluminium, and Oxygen and an increase in the weight/atomic% for Carbon, Nitrogen, and Sodium were noted compared to the baseline in the probiotic solution. The results in the probiotic group were comparable to the 0.1 M lactic acids. The pH changed from 5.78 to 3.06 at the end of 24 h in the probiotic group. Based on these findings, we conclude that exposure to probiotics can affect microhardness and surface roughness and cause leaching of essential elements like Calcium and Phosphorous from the enamel.
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Affiliation(s)
- Swagata Saha
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Aditi Chopra
- Department of Periodontology, Manipal College of Dental Sciences, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India.
| | - Shobha Ullas Kamath
- Department of Biochemistry, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
| | - Namita N Kashyap
- Department of Biochemistry, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, 576104, India
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Ramírez-Ramos CF, Saldarriaga-Giraldo CI, Yepes-Calderón M, Castilla-Agudelo GA, Aránzazu Uribe M, Saldarriaga Betancur S, Casto P, Gallego C, Londoño A, Rendon-Isaza JC, Cañas E, Porras Á, Uribe-Molano JD. Arterial lactate levels and their prognostic value in patients undergoing pulmonary thromboendarterectomy. Arch Peru Cardiol Cir Cardiovasc 2021; 2:96-102. [PMID: 38274565 PMCID: PMC10809776 DOI: 10.47487/apcyccv.v2i2.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 05/24/2021] [Indexed: 01/27/2024]
Abstract
Objective Evaluate the change of lactate levels and its prognostic role in the postoperative period of patients undergoing pulmonary thromboendarterectomy. Methods Retrospective study between 2001 and 2019. Patients older than 18 years and who underwent pulmonary thromboendarterectomy were included. The U Mann Whitney test was performed to evaluate the change between lactate levels, and Cox regression analysis to evaluate the relationship with mortality. Areas under the curve were constructed for lactate levels. Results Seventy-three patients were operated on during the study period. Median age was 51 years, 55% female. The median lactate on days 1 was 4.65 mml/L and on day 2 it was 1.62 mml/L with a change of 2.87 mml/L. No differences were found between the levels measured on day 1 and 2 between the people who died and those who did not on day 30. In the multivariate regression of COX, no relationship with mortality was found. The area under the curve shows regular performance on both day 1 and day 2 in predicting mortality outcomes. Conclusions The behavior of the lactate in patients undergoing pulmonary thromboendarterectomy shows a rapid change during the first hours after the procedure. No role was found as a predictor of mortality neither in-hospital nor in follow-up.
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Affiliation(s)
- Cristhian Felipe Ramírez-Ramos
- Department of Cardiology, Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of CardiologyUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Clara Inés Saldarriaga-Giraldo
- Department of Cardiology and Heart Failure, Universidad Pontificia Bolivariana, Clínica CardioVID. Universidad de Antioquia. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of Cardiology and Heart FailureUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Manuela Yepes-Calderón
- Universidad de Antioquia. Medellin, Colombia. Universidad de AntioquiaUniversidad de AntioquiaMedellinColombia
| | - Gustavo Adolfo Castilla-Agudelo
- Department of Cardiology, Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of CardiologyUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Mateo Aránzazu Uribe
- Department of Internal Medicine, Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of Internal MedicineUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Santiago Saldarriaga Betancur
- Department of Internal Medicine, Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of Internal MedicineUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Paulina Casto
- Department of Anesthesiology Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of AnesthesiologyUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Catalina Gallego
- Department of Cardiology and Heart Failure, Universidad Pontificia Bolivariana, Clínica CardioVID. Universidad de Antioquia. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of Cardiology and Heart FailureUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Alejandro Londoño
- Department of Pulmonology and Pulmonary Hypertension Clinic, Clínica CardioVID. Medellin, Colombia. Department of Pulmonology and Pulmonary Hypertension ClinicClínica CardioVIDMedellinColombia
| | - Juan Camilo Rendon-Isaza
- Cardiovascular Surgery Department, Universidad Pontificia Bolivariana Clínica CardioVID. Medellin, Colombia. Pontificia Universidad BolivarianaCardiovascular Surgery DepartmentUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Eliana Cañas
- Department of Epidemiology, Universidad Pontificia Bolivariana, Clínica CardioVID. Medellin, Colombia. Universidad Pontificia BolivarianaDepartment of EpidemiologyUniversidad Pontificia BolivarianaClínica CardioVIDMedellinColombia
| | - Álvaro Porras
- Department of Intensive Care Medicine and Cardiovascular Intensive Care, Clínica CardioVID. Medellin, Colombia. Department of Intensive Care Medicine and Cardiovascular Intensive CareClínica CardioVIDMedellinColombia
| | - Juan David Uribe-Molano
- Department of Intensive Care Medicine and Cardiovascular Intensive Care, Clínica CardioVID. Medellin, Colombia. Department of Intensive Care Medicine and Cardiovascular Intensive CareClínica CardioVIDMedellinColombia
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Özmen R, Bozguney M, Tekin Aİ, Eroglu T, Tuncay A. Impact of Single versus Double Clamp Technique on Blood Lactate Levels and Postoperative Complications in Coronary Artery Bypass Surgery. Braz J Cardiovasc Surg 2021; 37:55-64. [PMID: 33656827 PMCID: PMC8973127 DOI: 10.21470/1678-9741-2020-0025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Introduction Cardiopulmonary bypass (CPB) is associated with hyperlactatemia, which leads
to adverse clinical outcomes. No study has examined the effect of different
clamping techniques on postoperative hyperlactatemia (PHL). Thus, we aimed
to evaluate the impact of two different techniques on PHL and the clinical
outcomes in patients undergoing isolated coronary artery bypass surgery. Methods This retrospective study included 100 patients who underwent isolated CPB
either with single clamp technique (SCT, n=47) or double clamp technique
(DCT, n=53). Demographic and preoperative laboratory data, as well as
operative features and arterial blood lactate levels at the onset and at the
end of CPB, were collected from patient charts. Results Blood lactate levels collected at the end of CPB did not differ significantly
between groups whereas intraoperative lactate increased significantly in
both groups (P<0.005). PHL developed in 16 patients
(32%). There was no meaningful difference in SCT and DCT in this regard.
Left internal mammary artery was used more frequently in the DCT group than
in the SCT group. While the cross-clamp time was significantly longer in the
SCT group, there was no difference regarding CPB time. Among postoperative
complications, only the incidence of stroke was significantly higher in the
DCT group than in the SCT group (10.6% vs. 0%,
P=0.020). CPB time, cross-clamp time and numbers of
proximal saphenous graft and distal anastomosis showed a significant
positive correlation with the postoperative lactate level. In the regression
analysis, CPB time emerged as the only independent predictor of PHL (OR
1.04, CI 95% 1.01-1.07, P=0.011). Conclusion There was no difference in postoperative blood lactate levels between SCT and
DCT groups.
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Affiliation(s)
- Rifat Özmen
- Department of Cardiovascular Surgery, Erciyes Universitesi Tip Fakultesi, Kayseri, Turkey
| | - Muhammet Bozguney
- Department of Cardiovascular Surgery, Kayseri Egitim ve Arastirma Hastanesi, Kayseri, Turkey
| | - Ali İhsan Tekin
- Department of Cardiovascular Surgery, Kayseri Egitim ve Arastirma Hastanesi, Kayseri, Turkey
| | - Tamer Eroglu
- Department of Cardiovascular Surgery, Ömer Halisdemir University, Nigde, Turkey
| | - Aydin Tuncay
- Department of Cardiovascular Surgery, Erciyes Universitesi Tip Fakultesi, Kayseri, Turkey
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Wu J, Kim KH, Jeong K, Kim D, Kim CS, Ha JM, Chandra RP, Saddler JN. The production of lactic acid from chemi-thermomechanical pulps using a chemo-catalytic approach. Bioresour Technol 2021; 324:124664. [PMID: 33454446 DOI: 10.1016/j.biortech.2021.124664] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
Previous work has shown that sulfonation and oxidation of chemi-thermomechanical pulps (CTMPs) significantly enhanced enzyme accessibility to cellulose while recovering the majority of carbohydrates in the water-insoluble component. In the work reported here, modified (sulfonated and oxidized) CTMPs derived from hard-and-softwoods were used to produce a DL-mix of lactic acid via a chemo-catalytic approach using lanthanide triflate (Ln (OTf)3) catalysts (Ln = La, Nd, Er, and Yb). It was apparent that sulfonation and oxidation of chemi-thermomechanical pulps (CTMPs) also enhanced Ln(OTf)3 catalyst accessibility to the carbohydrate components of the pulps, with the Er(OTf)3 catalysts resulting in significant lactic acid production. Under optimum conditions (250 °C, 60 min, 0.5 mmol catalyst g-1 biomass), 72% and 67% of the respective total carbohydrate present in the hard-and-softwood CTMPs could be converted to lactic acid compared to the respective 59% and 51% yields obtained after energy-intensive ball milling.
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Affiliation(s)
- Jie Wu
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Kwang Ho Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Keunhong Jeong
- Department of Physics and Chemistry, Korea Military Academy, Seoul 01805, South Korea
| | - Dongwoo Kim
- Department of Physics and Chemistry, Korea Military Academy, Seoul 01805, South Korea
| | - Chang Soo Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jeong-Myeong Ha
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Richard P Chandra
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada
| | - Jack N Saddler
- Forest Product Biotechnology/Bioenergy Group, Department of Wood Science, Faculty of Forestry, University of British Columbia, 2424 Main Mall, Vancouver, BC V6T 1 Z4, Canada.
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Orak Y, Kocarslan A, Boran OF, Acıpayam M, Eroglu E, Kirisci M, Doganer A. Comparison of the operative and postoperative effects of del Nido and blood cardioplegia solutions in cardiopulmonary bypass surgery. Braz J Cardiovasc Surg 2020; 35:689-696. [PMID: 33118734 PMCID: PMC7598972 DOI: 10.21470/1678-9741-2019-0436] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVE Our goal was to compare the operative and postoperative effects of del Nido cardioplegia (DN group) and blood cardioplegia (BC group) performed in cardiac surgery. METHODS A total of 83 patients were included, separated into DN group and BC group. The operative and postoperative effects of the two groups were compared for the first 24 hours until extubation. The operative and postoperative complete blood count (CBC), biochemical values and clinical parameters were compared. RESULTS The first control activated clotting time (ACT) levels in DN group patients were lower (P=0.003) during the operation. The amount of cardioplegia in DN group were lower than that in BC group (P=0.001). The pump outflow and postoperative lactate level of DN group were lower than those of BC group (P=0.005, P=0.018, respectively), as well as the amounts of NaHCO3 (P=0.006) and KCl (P=0.001) used during the operation. The same occurred with the first monocytes (Mo) and mean corpuscular volume (MCV) levels in the postoperative intensive care unit (P=0.006, P=0.002). However, the first glucose level and the eosinophil (Eo) level were higher in DN group (P=0.011, P=0.047, respectively). CONCLUSION In the operative evaluation, the amount of cardioplegia, the first ACT levels, the pump outflow lactate level and the amounts of NaHCO3 and KCl in DN group were lower. In postoperative evaluation, measured level of lactate, Mo and MCV in DN group were all lower; their glucose and Eo levels were higher.
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Affiliation(s)
- Yavuz Orak
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Anesthesiology and Reanimation Kahramanmaras Turkey Department of Anesthesiology and Reanimation, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
| | - Aydemir Kocarslan
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Cardiovascular Surgery Kahramanmaraş Turkey Department of Cardiovascular Surgery, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaraş, Turkey
| | - Omer Faruk Boran
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Anesthesiology and Reanimation Kahramanmaras Turkey Department of Anesthesiology and Reanimation, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaras, Turkey
| | - Mehmet Acıpayam
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Cardiovascular Surgery Kahramanmaraş Turkey Department of Cardiovascular Surgery, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaraş, Turkey
| | - Erdinc Eroglu
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Cardiovascular Surgery Kahramanmaraş Turkey Department of Cardiovascular Surgery, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaraş, Turkey
| | - Mehmet Kirisci
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Cardiovascular Surgery Kahramanmaraş Turkey Department of Cardiovascular Surgery, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaraş, Turkey
| | - Adem Doganer
- Kahramanmaras Sutcu Imam University Faculty of Medicine Department of Biostatistics and Medical Informatics Kahramanmaraş Turkey Department of Biostatistics and Medical Informatics, Faculty of Medicine, Kahramanmaras Sutcu Imam University, Kahramanmaraş, Turkey
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Harky A, Fok M, Fraser H, Howard C, Rimmer L, Bashir M. Could Cerebrospinal Fluid Biomarkers Offer Better Predictive Value for Spinal Cord Ischaemia Than Current Neuromonitoring Techniques During Thoracoabdominal Aortic Aneurysm Repair - A Systematic Review. Braz J Cardiovasc Surg 2019; 34:464-471. [PMID: 31454201 PMCID: PMC6713370 DOI: 10.21470/1678-9741-2018-0375] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Objective Cerebrospinal fluid (CSF) drainage is a technique that has significantly
reduced the incidence of spinal cord ischaemia (SCI). We present results of
a systematic review to assess the literature on this topic in relation to
thoracoabdominal aortic aneurysm repair (TAAR). Methods Major medical databases were searched to identify papers related to CSF
biomarkers measured during TAAAR. Results Fifteen papers reported measurements of CSF biomarkers with 265 patients in
total. CSF biomarkers measured included S-100ß, neuron-specific
endolase (NSE), lactate, glial fibrillary acidic protein A (GFPa), Tau, heat
shock protein 70 and 27 (HSP70, HSP27), and proinflammatory cytokines.
Lactate and S-100ß were reported the most, but did not correlate with
SCI, which was also the case with NSE and TAU. GFPa showed significant CSF
level rises, both intra and postoperative in patients who suffered SCI and
warrants further investigation, similar results were seen with HSP70, HSP27
and IL-8. Conclusions Although there is significant interest in this topic, there still remains a
significant lack of high-quality studies investigating CSF biomarkers during
TAAR to detect SCI. A large and multicentre study is required to identify
the significant role of each biomarker.
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Affiliation(s)
- Amer Harky
- Liverpool Heart and Chest Hospital Department of Cardiothoracic Surgery Liverpool UK Department of Cardiothoracic Surgery, Liverpool Heart and Chest Hospital, Liverpool, UK
| | - Matthew Fok
- Royal Liverpool Hospital Department of Vascular Surgery Liverpool UK Department of Vascular Surgery, Royal Liverpool Hospital, Liverpool, UK
| | - Holly Fraser
- University of Liverpool School of Medicine Liverpool UK School of Medicine, University of Liverpool, Liverpool, UK
| | - Callum Howard
- University of Manchester Faculty of Biology, Medicine and Health Manchester UK Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Lara Rimmer
- University of Liverpool School of Medicine Liverpool UK School of Medicine, University of Liverpool, Liverpool, UK
| | - Mohamad Bashir
- Manchester Royal Infirmary Department of Aortovascular Surgery Manchester UK Department of Aortovascular Surgery, Manchester Royal Infirmary, Manchester, UK
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Londoño J, Niño C, Archila A, Valencia M, Cárdenas D, Perdomo M, Moncayo G, Vargas C, Vallejo CE, Hincapié C, Ascuntar J, León A, Jaimes F. Antibiotics has more impact on mortality than other early goal-directed therapy components in patients with sepsis: An instrumental variable analysis. J Crit Care 2018; 48:191-197. [PMID: 30218959 DOI: 10.1016/j.jcrc.2018.08.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Revised: 07/30/2018] [Accepted: 08/24/2018] [Indexed: 12/19/2022]
Abstract
PURPOSE To estimate the effect of each of the EGDT components, as well as of the antibiotics, on length-of-stay and mortality. METHODS Prospective cohort in three hospitals. Adult patients admitted by the Emergency Rooms (ER) with infection and any of systolic blood pressure < 90 mmHg or lactate >4 mmol/L. An instrumental analysis with hospital of admission as the instrumental variable was performed to estimate the effect of each intervention on hospital mortality and secondary outcomes. RESULTS Among 2587 patients evaluated 884 met inclusion criteria, with a hospital mortality rate of 17% (n = 150). In the instrumental analysis, the only intervention associated with an absolute reduction in mortality (21%) was the use of antibiotics in the first 3 h. In patients with lactate values ≥4 mmol/L in the ER, a non-decrease of at least 10% at six hours was independently associated with mortality (OR = 3.1; 95%CI = 1.5-6.2). CONCLUSIONS Among patients entering ER with infection and shock or hypoperfusion criteria, the use of appropriate antibiotics in the first 3 h is the measure that has the greatest impact on survival. In addition, among patients with hyperlactatemia >4 mmol/L, the clearance of >10% of lactate during resuscitation is associated with better outcomes.
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Affiliation(s)
- Jessica Londoño
- Department of Internal Medicine, University of Antioquia, Medellín, Colombia; Medical division, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - César Niño
- Department of Internal Medicine, University of Antioquia, Medellín, Colombia
| | - Andrea Archila
- Medical division, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - Marta Valencia
- Department of Internal Medicine, University of Antioquia, Medellín, Colombia; Medical division, IPS Universitaria León XIII, Medellín, Colombia
| | - Diana Cárdenas
- Medical division, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - Mayla Perdomo
- Medical division, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - Giovanny Moncayo
- Medical division, Hospital Pablo Tobón Uribe, Medellín, Colombia
| | - César Vargas
- Medical division, Hospital Universitario San Vicente Fundación, Medellín, Colombia
| | - Carlos E Vallejo
- Medical division, IPS Universitaria León XIII, Medellín, Colombia; GRAEPIC - Clinical Epidemiology Academic Research Group (Grupo Académico de Epidemiología Clínica), University of Antioquia; Medellín, Colombia
| | - Carolina Hincapié
- GRAEPIC - Clinical Epidemiology Academic Research Group (Grupo Académico de Epidemiología Clínica), University of Antioquia; Medellín, Colombia
| | - Johana Ascuntar
- GRAEPIC - Clinical Epidemiology Academic Research Group (Grupo Académico de Epidemiología Clínica), University of Antioquia; Medellín, Colombia
| | - Alba León
- GRAEPIC - Clinical Epidemiology Academic Research Group (Grupo Académico de Epidemiología Clínica), University of Antioquia; Medellín, Colombia
| | - Fabián Jaimes
- Department of Internal Medicine, University of Antioquia, Medellín, Colombia; GRAEPIC - Clinical Epidemiology Academic Research Group (Grupo Académico de Epidemiología Clínica), University of Antioquia; Medellín, Colombia; Research Direction, Hospital Universitario San Vicente Fundación, Medellín, Colombia.
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Forsyth J, Burt D, Ridley F, Mann C. Using lactate threshold to predict 5-km treadmill running performance in veteran athletes. Biol Sport 2017; 34:233-7. [PMID: 29158615 DOI: 10.5114/biolsport.2017.65999] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Revised: 01/25/2016] [Accepted: 01/23/2017] [Indexed: 12/03/2022] Open
Abstract
Measuring lactate threshold to predict endurance performance is difficult among veteran athletes, due to age-related decreases in net lactate concentration. The objective of this study was to determine whether lactate threshold, as assessed using the maximal deviation method (Dmax), which is not dependent on net values of lactate, could be used as a more valid measure of 5-km treadmill running performance than other methods of determining lactate threshold. Veteran runners (18 male and 18 female, aged 47.3±6.7 years) performed an incremental exercise test to establish mean treadmill velocity at lactate threshold using Dmax, a log-log method, a visual method, and a 4-mmol·L-1 method, and, on a separate occasion, completed a 5-km time trial. Mean treadmill velocity at Dmax was 12.2±1.8 km·h-1, not being significantly different to mean treadmill velocity (12.1±1.8 km·h-1) attained during the 5-km time trial (p>0.05); velocities were also significantly correlated (r=0.92, p<0.001), and limits of agreement narrow (-1.61 to 1.35 km·h-1). Correlations were weaker and limits of agreement wider for the other methods of lactate threshold determination. Using a two-way, mixed-methods ANOVA, there was no significant effect of sex when using the different methods of determining Tlac (F4,136=3.70, p=0.15). Mean treadmill velocity, when using Dmax for determining lactate threshold, can be used to predict 5-km running performance among male and female veteran athletes.
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Yin H, Yin H, Wang A, Shen L, Liu Y, Zheng Y. Catalytic Conversion of Glycerol to Lactic Acid Over Metallic Copper Nanoparticles and Reaction Kinetics. J Nanosci Nanotechnol 2017; 17:1255-1266. [PMID: 29683300 DOI: 10.1166/jnn.2017.12573] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Different-sized metallic Cu⁰ nanoparticles were prepared by the wet chemical reduction method with organic modifiers. The small-sized Cu⁰ nanoparticles (Cu(PEG)) prepared by using polyethylene glycol as the organic modifier exhibited high catalytic activity for the hydrothermal conversion of glycerol to lactic acid. When the reaction was carried out with the initial glycerol and NaOH concentrations of 1.0 and 1.1 mol L⁻¹ at 230 °C for 4 h, the lactic acid selectivity reached 91.9% at the glycerol conversion of 98.0%. Over CuPEG (36.9 nm) and Cublank (118.3 nm) catalysts, the reaction activation energies were 76.3 and 86.5 kJ mol⁻¹, respectively.
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Shen L, Yin H, Yin H, Liu S, Wang A. Conversion of Glycerol to Lactic Acid Catalyzed by Different-Sized Cu₂O Nanoparticles in NaOH Aqueous Solution. J Nanosci Nanotechnol 2017; 17:773-779. [PMID: 29634164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Different-sized Cu₂O nanoparticles with the average particle sizes ranging from 115 to 423 nm were prepared starting from CuSO₄ using ascorbic acid as the reductant at room temperature. When Cu₂O nanoparticles were used as the catalysts for hydrothermal conversion of glycerol at 230 °C in a NaOH aqueous solution, Cu₂O nanoparticles effectively catalyzed the hydrothermal conversion of glycerol to lactic acid as compared to the conventional hydrothermal conversion of glycerol in a “pure” NaOH aqueous solution. Small-sized Cu₂O nanoparticles showed higher catalytic activity than the large-sized ones. In a wide glycerol concentration range of 1–2.5 mol/L and a low mole ratio of Cu₂O nanoparticle to glycerol of 2.5:100, the glycerol conversion and lactic acid selectivity were more than 86.2% and 87.2%, respectively, after reacting at 230 °C for 2 h.
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Hashemikamangar SS, Pourhashemi SJ, Nekooimehr Z, Dehaki MG, Kharazifard MJ. Effect of Lactic Acid on Microleakage of Class V Low-Shrinkage Composite Restorations. J Dent (Tehran) 2016; 13:223-230. [PMID: 28127313 PMCID: PMC5253214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVES To assess the effect of lactic acid (LA) on microleakage of silorane-based composite restorations and methacrylate-based composites with self-etch and etch-and-rinse bonding systems. MATERIALS AND METHODS Class V cavities were prepared in 120 extracted human teeth, divided into four groups and restored as follows: 1. Silorane-based composite+P90 adhesive system (P90); 2. Filtek Z250+SE Bond (Z250SE); 3. Filtek Z350+SE Bond (Z350SE) and 4. Filtek Z250+Single Bond (Z250SB). Half of the samples in each group were immersed in LA and the other half in distilled water (DW) for seven days. Degree of microleakage was determined by dye penetration. Data were analyzed using Kruskal Wallis and Mann Whitney-U tests (type 1 error was considered 0.05 for primary and 0.017 for post-hoc tests). RESULTS No significant difference was found in microleakage between LA and DW groups. The difference among groups in gingival margin microleakage was significant (P<0.05). The highest degree of microleakage was seen in Z250SB; which was significantly higher than Z250SE (DW: P=0.012 and LA: P=0.002) and Z350SE (DW: P=0.002 and LA: P=0.014). Microleakage was not significantly different between Z250SE and Z350SE (DW: P=0.683 and LA: P=0.533). The degree of microleakage of P90 in both media was lower than Z250SB and higher than that of Z250SE and Z350SE; but these differences were not significant. CONCLUSIONS Immersion in LA has no effect on microleakage of class V composite restorations regardless of the type of composite and adhesive system. At gingival margins, the highest microleakage occurred in Z250SB followed by P90 and self-etch groups.
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Affiliation(s)
- Sedigheh Sadat Hashemikamangar
- Assistant Professor, Department of Operative Dentistry, Dental School, Tehran University of Medical Sciences, International Campus, Tehran, Iran
| | - Seyed Jalal Pourhashemi
- Associate Professor, Department of Pediatric Dentistry, Dental School, Tehran University of Medical Sciences, International Campus, Tehran, Iran
| | - Zohre Nekooimehr
- Dentist, Dental School, Tehran University of Medical Sciences, International Campus, Tehran, Iran
| | - Mehrzad Gholampur Dehaki
- Assistant Professor, Internal Medicine and Endocrinology, Medical Faculty, AJA University of Medical Sciences, Tehran, Iran,Corresponding author: M. Gholampour Dehaki, AJA University of Medical Sciences, Tehran, Iran,
| | - Mohamad Javad Kharazifard
- Statistical Consultant, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
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Noor SI, Dietz S, Heidtmann H, Boone CD, McKenna R, Deitmer JW, Becker HM. Analysis of the binding moiety mediating the interaction between monocarboxylate transporters and carbonic anhydrase II. J Biol Chem 2015; 290:4476-86. [PMID: 25561737 DOI: 10.1074/jbc.m114.624577] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proton-coupled monocarboxylate transporters (MCTs) mediate the exchange of high energy metabolites like lactate between different cells and tissues. We have reported previously that carbonic anhydrase II augments transport activity of MCT1 and MCT4 by a noncatalytic mechanism, while leaving transport activity of MCT2 unaltered. In the present study, we combined electrophysiological measurements in Xenopus oocytes and pulldown experiments to analyze the direct interaction between carbonic anhydrase II (CAII) and MCT1, MCT2, and MCT4, respectively. Transport activity of MCT2-WT, which lacks a putative CAII-binding site, is not augmented by CAII. However, introduction of a CAII-binding site into the C terminus of MCT2 resulted in CAII-mediated facilitation of MCT2 transport activity. Interestingly, introduction of three glutamic acid residues alone was not sufficient to establish a direct interaction between MCT2 and CAII, but the cluster had to be arranged in a fashion that allowed access to the binding moiety in CAII. We further demonstrate that functional interaction between MCT4 and CAII requires direct binding of the enzyme to the acidic cluster (431)EEE in the C terminus of MCT4 in a similar fashion as previously shown for binding of CAII to the cluster (489)EEE in the C terminus of MCT1. In CAII, binding to MCT1 and MCT4 is mediated by a histidine residue at position 64. Taken together, our results suggest that facilitation of MCT transport activity by CAII requires direct binding between histidine 64 in CAII and a cluster of glutamic acid residues in the C terminus of the transporter that has to be positioned in surroundings that allow access to CAII.
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Affiliation(s)
- Sina Ibne Noor
- From the Department of Biology, Division of Zoology/Membrane Transport and
| | - Steffen Dietz
- From the Department of Biology, Division of Zoology/Membrane Transport and
| | - Hella Heidtmann
- From the Department of Biology, Division of Zoology/Membrane Transport and the Department of Biology, Division of General Zoology, University of Kaiserslautern, D-67653 Kaiserslautern, Germany and
| | - Christopher D Boone
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Robert McKenna
- the Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610
| | - Joachim W Deitmer
- the Department of Biology, Division of General Zoology, University of Kaiserslautern, D-67653 Kaiserslautern, Germany and
| | - Holger M Becker
- From the Department of Biology, Division of Zoology/Membrane Transport and
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Ikehara Y, Arai K, Furukawa N, Ohno T, Miyake T, Fushinobu S, Nakajima M, Miyanaga A, Taguchi H. The core of allosteric motion in Thermus caldophilus L-lactate dehydrogenase. J Biol Chem 2014; 289:31550-64. [PMID: 25258319 DOI: 10.1074/jbc.m114.599092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
For Thermus caldophilus L-lactate dehydrogenase (TcLDH), fructose 1,6-bisphosphate (FBP) reduced the pyruvate S(0.5) value 10(3)-fold and increased the V(max) value 4-fold at 30 °C and pH 7.0, indicating that TcLDH has a much more T state-sided allosteric equilibrium than Thermus thermophilus L-lactate dehydrogenase, which has only two amino acid replacements, A154G and H179Y. The inactive (T) and active (R) state structures of TcLDH were determined at 1.8 and 2.0 Å resolution, respectively. The structures indicated that two mobile regions, MR1 (positions 172-185) and MR2 (positions 211-221), form a compact core for allosteric motion, and His(179) of MR1 forms constitutive hydrogen bonds with MR2. The Q4(R) mutation, which comprises the L67E, H68D, E178K, and A235R replacements, increased V(max) 4-fold but reduced pyruvate S(0.5) only 5-fold in the reaction without FBP. In contrast, the P2 mutation, comprising the R173Q and R216L replacements, did not markedly increase V(max), but 10(2)-reduced pyruvate S(0.5), and additively increased the FBP-independent activity of the Q4(R) enzyme. The two types of mutation consistently increased the thermal stability of the enzyme. The MR1-MR2 area is a positively charged cluster, and its center approaches another positively charged cluster (N domain cluster) across the Q-axis subunit interface by 5 Å, when the enzyme undergoes the T to R transition. Structural and kinetic analyses thus revealed the simple and unique allosteric machinery of TcLDH, where the MR1-MR2 area pivotally moves during the allosteric motion and mediates the allosteric equilibrium through electrostatic repulsion within the protein molecule.
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Affiliation(s)
- Yoko Ikehara
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Kazuhito Arai
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Nayuta Furukawa
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Tadashi Ohno
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Tatsuya Miyake
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Shinya Fushinobu
- the Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan, and
| | - Masahiro Nakajima
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan
| | - Akimasa Miyanaga
- the Department of Chemistry, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Hayao Taguchi
- From the Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda, Chiba 278-8510, Japan,
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Klier M, Andes FT, Deitmer JW, Becker HM. Intracellular and extracellular carbonic anhydrases cooperate non-enzymatically to enhance activity of monocarboxylate transporters. J Biol Chem 2013; 289:2765-75. [PMID: 24338019 DOI: 10.1074/jbc.m113.537043] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Proton-coupled monocarboxylate transporters (MCTs) are carriers of high-energy metabolites such as lactate, pyruvate, and ketone bodies and are expressed in most tissues. It has previously been shown that transport activity of MCT1 and MCT4 is enhanced by the cytosolic carbonic anhydrase II (CAII) independent of its catalytic activity. We have now studied the influence of the extracellular, membrane-bound CAIV on transport activity of MCT1/4, heterologously expressed in Xenopus oocytes. Coexpression of CAIV with MCT1 and MCT4 resulted in a significant increase in MCT transport activity, even in the nominal absence of CO2/HCO3(-). CAIV-mediated augmentation of MCT activity was independent of the CAIV catalytic function, since application of the CA-inhibitor ethoxyzolamide or coexpression of the catalytically inactive mutant CAIV-V165Y did not suppress CAIV-mediated augmentation of MCT transport activity. The interaction required CAIV at the extracellular surface, since injection of CAIV protein into the oocyte cytosol did not augment MCT transport function. The effects of cytosolic CAII (injected as protein) and extracellular CAIV (expressed) on MCT transport activity, were additive. Our results suggest that intra- and extracellular carbonic anhydrases can work in concert to ensure rapid shuttling of metabolites across the cell membrane.
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Affiliation(s)
- Michael Klier
- From the Division of General Zoology, Department of Biology, University of Kaiserslautern D-67653 Kaiserslautern, Germany and
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Elustondo PA, White AE, Hughes ME, Brebner K, Pavlov E, Kane DA. Physical and functional association of lactate dehydrogenase (LDH) with skeletal muscle mitochondria. J Biol Chem 2013; 288:25309-25317. [PMID: 23873936 DOI: 10.1074/jbc.m113.476648] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The intracellular lactate shuttle hypothesis posits that lactate generated in the cytosol is oxidized by mitochondrial lactate dehydrogenase (LDH) of the same cell. To examine whether skeletal muscle mitochondria oxidize lactate, mitochondrial respiratory oxygen flux (JO2) was measured during the sequential addition of various substrates and cofactors onto permeabilized rat gastrocnemius muscle fibers, as well as isolated mitochondrial subpopulations. Addition of lactate did not alter JO2. However, subsequent addition of NAD(+) significantly increased JO2, and was abolished by the inhibitor of mitochondrial pyruvate transport, α-cyano-4-hydroxycinnamate. In experiments with isolated subsarcolemmal and intermyofibrillar mitochondrial subpopulations, only subsarcolemmal exhibited NAD(+)-dependent lactate oxidation. To further investigate the details of the physical association of LDH with mitochondria in muscle, immunofluorescence/confocal microscopy and immunoblotting approaches were used. LDH clearly colocalized with mitochondria in intact, as well as permeabilized fibers. LDH is likely localized inside the outer mitochondrial membrane, but not in the mitochondrial matrix. Collectively, these results suggest that extra-matrix LDH is strategically positioned within skeletal muscle fibers to functionally interact with mitochondria.
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Affiliation(s)
- Pia A Elustondo
- From the Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 4R2 and
| | | | | | - Karen Brebner
- Psychology, St. Francis Xavier University, Antigonish, Nova Scotia B2G 2W5, Canada
| | - Evgeny Pavlov
- From the Department of Physiology and Biophysics, Dalhousie University, Halifax, NS B3H 4R2 and
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Ruan GX, Kazlauskas A. Lactate engages receptor tyrosine kinases Axl, Tie2, and vascular endothelial growth factor receptor 2 to activate phosphoinositide 3-kinase/Akt and promote angiogenesis. J Biol Chem 2013; 288:21161-21172. [PMID: 23754286 DOI: 10.1074/jbc.m113.474619] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although a high level of lactate is quintessential to both tumors and wound healing, the manner by which lactate impacts endothelial cells to promote angiogenesis and thereby create or restore vascular perfusion to growing tissues has not been fully elucidated. Here we report that lactate activated the PI3K/Akt pathway in primary human endothelial cells. Furthermore, activating this signaling pathway was required for lactate-stimulated organization of endothelial cells into tubes and for sprouting of vessels from mouse aortic explants. Lactate engaged the PI3K/Akt pathway via ligand-mediated activation of the three receptor tyrosine kinases Axl, Tie2, and VEGF receptor 2. Neutralizing the ligands for these receptor tyrosine kinases, pharmacologically inhibiting their kinase activity or suppressing their expression largely eliminated the ability of cells and explants to respond to lactate. Elucidating the mechanism by which lactate communicates with endothelial cells presents a previously unappreciated opportunity to improve our understanding of the angiogenic program and to govern it.
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Affiliation(s)
- Guo-Xiang Ruan
- From the Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114
| | - Andrius Kazlauskas
- From the Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts 02114.
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