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Calligari PA, Salgado GF, Pelupessy P, Lopes P, Ouazzani J, Bodenhausen G, Abergel D. Insights into internal dynamics of 6-phosphogluconolactonase from Trypanosoma brucei studied by nuclear magnetic resonance and molecular dynamics. Proteins 2012; 80:1196-210. [DOI: 10.1002/prot.24019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 11/23/2011] [Accepted: 12/04/2011] [Indexed: 11/05/2022]
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Lopes P, Misbert E. [The 10 commandments for cesarean section]. GYNECOLOGIE, OBSTETRIQUE & FERTILITE 2011; 39:601-602. [PMID: 21996328 DOI: 10.1016/j.gyobfe.2011.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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Jamin C, André G, Audebert A, Christin-Maître S, Elia D, Harvey T, Letombe B, Lopes P, Moreau C, Nisand I, Pélissier C. Oublis de la contraception hormonale : réflexions sur leur prise en charge en pratique quotidienne. ACTA ACUST UNITED AC 2011; 39:644-55. [DOI: 10.1016/j.gyobfe.2011.08.031] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Accepted: 07/31/2011] [Indexed: 10/16/2022]
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Duval-Arnould X, Lopes P, Philippe HJ. [Residentship in obstetrics and gynaecology in Nantes]. GYNECOLOGIE, OBSTETRIQUE & FERTILITE 2011; 39:402. [PMID: 21602083 DOI: 10.1016/j.gyobfe.2011.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
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Coutin AS, Lopes P. [About the recommendations on emergency contraception in Yeni's 2010 report on medical management of people exposed to HIV. Is there nothing new to propose?]. J Gynecol Obstet Hum Reprod 2011; 40:273-275. [PMID: 21333464 DOI: 10.1016/j.jgyn.2011.01.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 01/11/2011] [Indexed: 05/30/2023]
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106
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Bettencourt A, Florindo HF, Ferreira IFS, Matos A, Monteiro J, Neves C, Lopes P, Calado A, Castro M, Almeida AJ. Incorporation of tocopherol acetate-containing particles in acrylic bone cement. J Microencapsul 2010; 27:533-41. [PMID: 20459296 DOI: 10.3109/02652048.2010.484106] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Acrylic bone cement (BC) is used in orthopaedic surgery to anchor cemented prostheses to bone. Association of antioxidant molecules to BC may suppress reactive species injury which contributes to implant failure. Tocopherol acetate (ATA)-loaded polymethylmethacrylate (PMMA) particles (ATA(PMMA)) were prepared by single emulsion solvent evaporation technique and were incorporated into BC. An encapsulation efficiency of 84% (w/w) was obtained and drug release studies showed distinct ATA release profiles and mechanisms before and after particle incorporation into BC. Experimental data, analysed using first-order, Higuchi and Korsmeyer-Peppas models revealed that ATA was released from particles by a Fickian diffusion mechanism while a non-Fickian transport was observed upon particle incorporation in BC. There were no changes in the mechanical properties of BC specimens containing ATA(PMMA) particles, in contrast to what was observed when ATA was loaded directly into BC. Overall, ATA(PMMA) particles are potential carriers for the incorporation of an antioxidant drug into BC.
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Cottin F, Barrey E, Lopes P, Billat V. Effect of repeated exercise and recovery on heart rate variability in elite trotting horses during high intensity interval training. Equine Vet J 2010:204-9. [PMID: 17402419 DOI: 10.1111/j.2042-3306.2006.tb05540.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING STUDY Interval training is a commonly used training method for trotting horses. In addition, trainers are provided with efficient and inexpensive heart rate monitor devices for the management of training. HYPOTHESIS Since the high frequency (HF) frequency peak (fHF) of heart rate variability (HRV) corresponds to the breathing frequency in combination with stride frequency during trotting, it is hypothesised that modifications of breathing and stride frequencies induced by repeated exercise could be detected from fHF. METHODS RR interval time series of 7 trotting horses were recorded during an interval training session. Interval training was made up of 5 successive 800 m high-velocity trotting runs (H1, H2...H5) separated by 1 min recovery bouts at low speed (R1, R2...R5). Fast Fourier transform (FFT) and Poincaré plot analysis techniques were applied to RR series. RESULTS Repeated exercise had significant effects on HRV components during interval training. Despite constant trotting velocities during high-speed and recovery, repetition induced a decrease in mean RR interval (H1: 295 +/- 19 vs. H5: 283 +/- 15 msec, P<0.05) and in the root mean square of successive differences in RR series (RMSSD; H1: 6.31 +/- 1.28 vs. H5: 5.31 +/- 1.31 msec, P<0.05). Furthermore, high-speed and recovery repetitions induced an increase in fHF (H1: 1.37 +/- 0.35 vs. H5: 1.62 +/- 0.40 Hz and R1: 0.22 +/- 0.02 vs. R4: 0.64 +/- 0.38 Hz, P<0.05). Hence, recovery induced a decrease in the s.d. of the successive RR series (SDRR; R3: 10.5 +/- 3.96 vs. R5: 6.17 +/- 2.65 msecs, P>0.05) and in the long term index of Poincaré plot (SD2; R1: 43.29 +/- 28.90 vs. R5: 18.19 +/- 9.35 msecs, P<0.05). CONCLUSIONS The observed increase in fHF during the interval training could be induced by alterations of the coupling between breathing and stride frequency linked to the emergence of fatigue. The decrease in SD2 and SDRR during successive recovery bouts could be linked with a deterioration of the recovery pattern. POTENTIAL RELEVANCE HRV can provide breathing frequency data of Standardbreds during training without any respiratory device. Furthermore, HRV could provide useful makers of the emergence of fatigue states during training.
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Vanommeslaeghe K, Hatcher E, Acharya C, Kundu S, Zhong S, Shim J, Darian E, Guvench O, Lopes P, Vorobyov I, MacKerell AD. CHARMM general force field: A force field for drug-like molecules compatible with the CHARMM all-atom additive biological force fields. J Comput Chem 2010; 31:671-90. [PMID: 19575467 PMCID: PMC2888302 DOI: 10.1002/jcc.21367] [Citation(s) in RCA: 2844] [Impact Index Per Article: 203.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The widely used CHARMM additive all-atom force field includes parameters for proteins, nucleic acids, lipids, and carbohydrates. In the present article, an extension of the CHARMM force field to drug-like molecules is presented. The resulting CHARMM General Force Field (CGenFF) covers a wide range of chemical groups present in biomolecules and drug-like molecules, including a large number of heterocyclic scaffolds. The parametrization philosophy behind the force field focuses on quality at the expense of transferability, with the implementation concentrating on an extensible force field. Statistics related to the quality of the parametrization with a focus on experimental validation are presented. Additionally, the parametrization procedure, described fully in the present article in the context of the model systems, pyrrolidine, and 3-phenoxymethylpyrrolidine will allow users to readily extend the force field to chemical groups that are not explicitly covered in the force field as well as add functional groups to and link together molecules already available in the force field. CGenFF thus makes it possible to perform "all-CHARMM" simulations on drug-target interactions thereby extending the utility of CHARMM force fields to medicinally relevant systems.
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Ploteau S, Haudebourg M, Philippe HJ, Lopes P. Stérilisation tubaire par voie hystéroscopique chez les femmes de plus de quarante ans : quelle motivation pour ces femmes ? ACTA ACUST UNITED AC 2009; 37:775-9. [DOI: 10.1016/j.gyobfe.2009.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 08/12/2009] [Indexed: 12/01/2022]
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Lopes P, Vaucel E, Laboisse C, Dahlab A, Coste-Burel M, Philippe H. O541 Human papillomavirus (HPV) genotype distribution in women with normal cytological diagnosis followed in routine clinical practice at the Nantes University Hospital, France. Int J Gynaecol Obstet 2009. [DOI: 10.1016/s0020-7292(09)60914-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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111
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Deforges S, Branchu J, Biondi O, Grondard C, Pariset C, Lécolle S, Lopes P, Vidal PP, Chanoine C, Charbonnier F. Motoneuron survival is promoted by specific exercise in a mouse model of amyotrophic lateral sclerosis. J Physiol 2009; 587:3561-72. [PMID: 19491245 DOI: 10.1113/jphysiol.2009.169748] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Several studies using transgenic mouse models of familial amyotrophic lateral sclerosis (ALS) have reported a life span increase in exercised animals, as long as animals are submitted to a moderate-intensity training protocol. However, the neuroprotective potential of exercise is still questionable. To gain further insight into the cellular basis of the exercise-induced effects in neuroprotection, we compared the efficiency of a swimming-based training, a high-frequency and -amplitude exercise that preferentially recruits the fast motor units, and of a moderate running-based training, that preferentially triggers the slow motor units, in an ALS mouse model. Surprisingly, we found that the swimming-induced benefits sustained the motor function and increased the ALS mouse life span by about 25 days. The magnitude of this beneficial effect is one of the highest among those induced by any therapeutic strategy in this disease. We have shown that, unlike running, swimming significantly delays spinal motoneuron death and, more specifically, the motoneurons of large soma area. Analysis of the muscular phenotype revealed a swimming-induced relative maintenance of the fast phenotype in fast-twitch muscles. Furthermore, the swimming programme preserved astrocyte and oligodendrocyte populations in ALS spinal cord. As a whole, these data are highly suggestive of a causal relationship not only linking motoneuron activation and protection, but also motoneuron protection and the maintenance of the motoneuron surrounding environment. Basically, exercise-induced neuroprotective mechanisms provide an example of the molecular adaptation of activated motoneurons.
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Grosdemouge I, Engrand JB, Dhainault C, Marchand F, Martigny H, Thevenot J, Villefranque V, Lopes P, Panel P. [Essure implants for tubal sterilisation in France]. ACTA ACUST UNITED AC 2009; 37:389-95. [PMID: 19410494 DOI: 10.1016/j.gyobfe.2009.03.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Accepted: 03/25/2009] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Law no. 2001-588 of 4 July 2001 liberalised the practice of tubal sterilisation in France, at the same time as a new hysteroscopic method of female sterilization appeared. The growth of this method has been spurred by the reduced need for analgesia, absence of incision and scar, reduced duration of hospitalization and diminution of costs. The aim of this study was to analyse the use of the Essure procedure in France. PATIENTS AND METHODS This multicentre study covered seven French facilities from January 2004 through June 2006. This study included 1061 attempted placements of the Essure micro-insert, marketed by Conceptus SAS (France). RESULTS The first placement attempt was successful in 992 cases (94.4%). The success rate for second attempts was 59% (n = 23). Mean VAS was 3,23 +/- 0.19. Ninety-three percent of patients undergoing Essure placement were satisfied or very satisfied. DISCUSSION AND CONCLUSION Tubal sterilisation with Essure micro-inserts is a reliable and reproducible method that requires a short period of training. In the future, the hysteroscopic pathway will replace the laparoscopic route.
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Debois D, Hamze K, Guérineau V, Le Caër JP, Holland IB, Lopes P, Ouazzani J, Séror SJ, Brunelle A, Laprévote O. In situ localisation and quantification of surfactins in a Bacillus subtilis swarming community by imaging mass spectrometry. Proteomics 2009. [DOI: 10.1002/pmic.200890094] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Debois D, Hamze K, Guérineau V, Le Caër JP, Holland IB, Lopes P, Ouazzani J, Séror SJ, Brunelle A, Laprévote O. In situ localisation and quantification of surfactins in a Bacillus subtilis swarming community by imaging mass spectrometry. Proteomics 2008; 8:3682-91. [DOI: 10.1002/pmic.200701025] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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115
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Gueguen-Chaignon V, Chaptal V, Larivière L, Costa N, Lopes P, Morera S, Nessler S. Crystal structure and functional analysis identify the P-loop containing protein YFH7 of Saccharomyces cerevisiae as an ATP-dependent kinase. Proteins 2008; 71:804-12. [PMID: 18004758 DOI: 10.1002/prot.21740] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Genome sequencing projects have revealed that P-loop proteins are highly represented in all organisms and that many of them have no attributed function. They are characterized by a conserved nucleotide-binding domain and carry different activities implicated in many cellular processes. Saccharomyces cerevisiae YFH7 is one of these P-loop proteins of unknown function. In this work we tried to integrate bioinformatics, structure, and enzymology to discover the function of YFH7. Sequence analysis revealed that yeast YFH7 is a yeast-specific protein showing weak similarity with the phosphoribulokinase/uridine kinase/bacterial pantothenate kinase (PRK/URK/PANK) subfamily of P-loop containing kinases. A large insertion of about 100 residues distinguishes YFH7 from other members of the family. The 1.95 A resolution crystal structure of YFH7 solved using the SAD method confirmed that YFH7 has a fold similar to the PRK/URK/PANK family, with the characteristic core, lid, and NMP(bind) domains. An additional alpha/beta domain of novel topology corresponds to the large sequence insertion. Structural and ligand binding analysis combined with enzymatic assays suggest that YFH7 is an ATP-dependent small molecule kinase with new substrate specificity.
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Grondard C, Biondi O, Pariset C, Lopes P, Deforges S, Lécolle S, Gaspera BD, Gallien CL, Chanoine C, Charbonnier F. Exercise-induced modulation of calcineurin activity parallels the time course of myofibre transitions. J Cell Physiol 2007; 214:126-35. [PMID: 17559060 DOI: 10.1002/jcp.21168] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
This study establishes a causal link between the limitation of myofibre transitions and modulation of calcineurin activity, during different exercise paradigms. We have designed a new swimming-based training protocol in order to draw a comparison between a high frequency and amplitude exercise (swimming) and low frequency and amplitude exercise (running). We initially analysed the time course of muscle adaptations to a 6- or 12-week swimming- or running-based training exercise program, on two muscles of the mouse calf, the slow-twitch soleus and the fast-twitch plantaris. The magnitude of exercise-induced muscle plasticity proved to be dependent on both the muscle type and the exercise paradigm. In contrast to the running-based training which generated a continuous increase of the slow phenotype throughout a 12-week training program, swimming induced transitions to a slower phenotype which ended after 6 weeks of training. We then compared the time course of the exercise-induced changes in calcineurin activity during muscle adaptation to training. Both exercises induced an initial activation followed by the inhibition of calcineurin. In the muscles of animals submitted to a 12-week swimming-based training, this inhibition was concomitant with the end of myofibre transition. Calcineurin inhibition was a consequence of the inhibition of its catalytic subunit gene expression on one hand, and of the expression increase of the modulatory calcineurin interacting proteins 1 gene (MCIP1), on the other. The present study provides the first experimental cues for an interpretation of muscle phenotypic variation control.
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Lepretre PM, Lopes P, Koralsztein JP, Billat V. Fatigue responses in exercise under control of VO2. Int J Sports Med 2007; 29:199-205. [PMID: 17879879 DOI: 10.1055/s-2007-965066] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
To examine the fatigue response during an exhaustive heavy exercise performed under control of oxygen uptake (SS@V.O (2)Delta50) or power output (SS@pDelta50), eleven trained male subjects performed an incremental test to determine the peak of the oxygen uptake value (V.O (2peak)) and lactate threshold and two exhaustive steady-state cycling exercises at the intermediate value between the lactate threshold and V.O (2peak) (SS@V.O (2)Delta50 and SS@pDelta50). The control of V.O (2) induced an oscillation of the power output, which lowered the average power output (276 +/- 47 vs. 315 +/- 40 W, p = 0.004) and cancelled the slow component of oxygen kinetics. However, all subjects reached maximal cardiac output (CO) and heart rate (HR) values which were sustained almost two times longer in SS@V.O (2)Delta50 compared to SS@pDelta50 (979 +/- 854 vs. 475 +/- 236 s, p = 0.046 for CO and 1050 +/- 890 vs. 513 +/- 288 s, p = 0.037 for HR). Furthermore, SS@pDelta50 elicited V.O (2peak) but not SS@V.O (2)Delta50 (4963 +/- 434 vs. 4723 +/- 460 mL . min (-1), p = 0.026). Finally, the time spent at the maximal CO and HR values is correlated with time to exhaustion at V.O (2)Delta50. In conclusion, the cause of fatigue does not seem to have the same origin during exhaustive supra-lactate threshold exercise under control of V.O (2) (V.O (2)Delta50) compared to constant power output (pDelta50), while both elicit the maximal HR and CO values.
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Roue A, Laboisse C, Winer N, Darnis E, Bouquin R, Lopes P, Philippe HJ. [Extra-uterine pelvic leiomyoma: diagnosis and practical management]. ACTA ACUST UNITED AC 2007; 36:403-8. [PMID: 17408875 DOI: 10.1016/j.jgyn.2007.02.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2005] [Revised: 03/20/2006] [Accepted: 02/26/2007] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To analyze the possibilities of setting up a therapy for extra-uterine pelvic leiomyomas. METHODS Three cases of leiomyomas of the broad ligament, of the round ligament and of the ovary, and literature review. RESULTS Little is known about physiopathology of extra-uterine leiomyoma. The diagnosis of extra-uterine leiomyoma is based on histopathological analysis, using standard histology, and immunohistochemistry with anti-desmin and anti smooth muscle actin antibodies. The main differential diagnoses are fibroma, fibrothecoma, ovarian fibrosarcoma, and gastrointestinal stromal tumors. To define criteria of malignancy, we use Bell's classification without being sure that the uterine and extra-uterine models are comparable. So there is a risk of ignoring a low grade leiomyosarcoma. Providing therapy depends on the clinicopathologic features: the so called "parasitic leiomyoma", a tumor developed at the expense of local smooth muscle cells, metastasis of a benign metastasizing leiomyoma or leiomyomatosis peritonealis disseminata. CONCLUSION The extra-uterine leiomyoma has no precise nosologic status and no specific criteria of benignity; thus no precise evolution can be predicted. We must be extremely careful, and the issue of the monitoring and long-term therapy of patients must come up.
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Cottin F, Médigue C, Lopes P, Leprêtre PM, Heubert R, Billat V. Ventilatory Thresholds Assessment from Heart Rate Variability during an Incremental Exhaustive Running Test. Int J Sports Med 2007; 28:287-94. [PMID: 17024637 DOI: 10.1055/s-2006-924355] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The present study examined whether the ventilatory thresholds during an incremental exhaustive running test could be determined using heart rate variability (HRV) analysis. Beat-to-beat RR interval, V(.-)O (2), V(.-)CO (2) and V(.-) (E) of twelve professional soccer players were collected during an incremental test performed on a track until exhaustion. The "smoothed pseudo Wigner-Ville distribution" (SPWVD) time-frequency analysis method was applied to the RR time series to compute the usual HRV components vs. running speed stages. The ventilatory equivalent method was used to assess the ventilatory thresholds (VT1 and VT2) from respiratory components. In addition, ventilatory thresholds were assessed from the instantaneous components of respiratory sinus arrhythmia (RSA) by two different methods: 1) from the high frequency peak of HRV ( FHF), and 2) from the product of the spectral power contained within the high frequency band (0.15 Hz to fmax) by FHF (HF x FHF) giving two thresholds: HFT1 and HFT2. Since the relationship between FHF and running speed was linear for all subjects, the VTs could not be determined from FHF. No significant differences were found between respective running speeds at VT1 vs. HFT1 (9.83 +/- 1.12 vs. 10.08 +/- 1.29 km x h (-1), n.s.) nor between the respective running speeds at VT2 vs. HFT2 (12.55 +/- 1.31 vs. 12.58 +/- 1.33 km x h (-1), n.s.). Linear regression analysis showed a strong correlation between VT1 vs. HFT1 (R (2) = 0.94, p < 0.001) and VT2 vs. HFT2 (R (2) = 0.96, p < 0.001). The Bland-Altman plot analysis reveals that the assessment from RSA gives an accurate estimation of the VTs, with HF x FHF providing a reliable index for the ventilatory thresholds detection. This study has shown that VTs could be assessed during an incremental running test performed on a track using a simple beat-to-beat heart rate monitor, which is less expensive and complex than the classical respiratory measurement devices.
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Cottin F, Leprêtre PM, Lopes P, Papelier Y, Médigue C, Billat V. Assessment of ventilatory thresholds from heart rate variability in well-trained subjects during cycling. Int J Sports Med 2007; 27:959-67. [PMID: 17190003 DOI: 10.1055/s-2006-923849] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The purpose of this study was to implement a new method for assessing the ventilatory thresholds from heart rate variability (HRV) analysis. ECG, VO2, VCO2, and VE were collected from eleven well-trained subjects during an incremental exhaustive test performed on a cycle ergometer. The "Short-Term Fourier Transform" analysis was applied to RR time series to compute the high frequency HRV energy (HF, frequency range: 0.15 - 2 Hz) and HF frequency peak (fHF) vs. power stages. For all subjects, visual examination of ventilatory equivalents, fHF, and instantaneous HF energy multiplied by fHF (HF.fHF) showed two nonlinear increases. The first nonlinear increase corresponded to the first ventilatory threshold (VT1) and was associated with the first HF threshold (T(RSA1) from fHF and HFT1 from HF.fHF detection). The second nonlinear increase represented the second ventilatory threshold (VT2) and was associated with the second HF threshold (T(RSA2) from fHF and HFT2 from HF.fHF detection). HFT1 , T(RSA1), HFT2, and T(RSA2) were, respectively, not significantly different from VT1 (VT1 = 219 +/- 45 vs. HFT1 = 220 +/- 48 W, p = 0.975; VT1 vs. T(RSA1) = 213 +/- 56 W, p = 0.662) and VT2 (VT2 = 293 +/- 45 vs. HFT2 = 294 +/- - 48 W, p = 0.956; vs. T(RSA2) = 300 +/- 58 W, p = 0.445). In addition, when expressed as a function of power, HFT1, T(RSA1), HFT2, and T(RSA2) were respectively correlated with VT1 (with HFT1 r2 = 0.94, p < 0.001; with T(RSA1) r2 = 0.48, p < 0.05) and VT2 (with HFT2 r2 = 0.97, p < 0.001; with T(RSA2 )r2 = 0.79, p < 0.001). This study confirms that ventilatory thresholds can be determined from RR time series using HRV time-frequency analysis in healthy well-trained subjects. In addition it shows that HF.fHF provides a more reliable and accurate index than fHF alone for this assessment.
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Cottin F, Slawinski J, Lopes P, Van de Louw A, Billat V. Effect of a 24-h continuous walking race on cardiac autonomic control. Eur J Appl Physiol 2006; 99:245-50. [PMID: 17115176 DOI: 10.1007/s00421-006-0341-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2006] [Indexed: 10/23/2022]
Abstract
This study investigated the relationships between walking speed and heart rate (HR) variability (HRV) in eleven subjects during a 24-h race. It was hypothesized that the nycthemeral rhythm on HR is preserved during the race. RR intervals and walking speed were measured. Fast Fourier transform was applied to samples of 1,024 successive RR intervals collected every hour from a HR monitor. Walking speed was averaged every hour and decreased (first lap: 8.8 +/- 0.3 vs. last lap: 7.3 +/- 0.8 km h(-1), P < 0.001) with HR also decreasing (max at 19:00 h: 143 +/- 9 vs. min at 7:00 h: 117 +/- 14 beats min(-1), P < 0.001) following a third order polynomial shape. HRV power spectral components followed distribution patterns similar to the mean RR during the race with a minimum in the early evening (19:00-20:00 h) and a maximum in the morning (5:00-8:00 h). Thus, as for mean RR, spectral components over time are also fitted to a third order polynomial regression. LF/HF ratio increased linearly (min = 0.5 +/- 0.3, max = 2.8 +/- 5.3, P = 0.02). Although mean HF peak did not decrease significantly over time, it was positively correlated with walking speed. In conclusion, this study showed that despite a constant decrease in walking speed, HR circadian rhythm is preserved during a continuous 24-h walking race. The short-term HRV components remain linked to HR whereas the LF/HF ratio increases linearly until the end of the race whatever HR is.
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Chaignon P, Cortial S, Ventura A, Lopes P, Halgand F, Laprevote O, Ouazzani J. Purification and identification of a Bacillus nitroreductase: Potential use in 3,5-DNBTF biosensoring system. Enzyme Microb Technol 2006. [DOI: 10.1016/j.enzmictec.2006.04.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Oliveira PA, Colaço A, De la Cruz LF, Lopes P, Lopes C. E-cadherin expression during urothelial carcinogenesis induced by N-butyl-N-(4-hydroxybutyl) nitrosamine in rats. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2006; 25:425-32. [PMID: 17167984] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
An alteration in the expression of E-cadherin has been observed in many epithelial neoplasms. No data exist, however, for the expression of this protein in an animal model for urinary bladder cancer. The present study investigated the expression of E-cadherin in rat urothelial preneoplastic lesions and tumours induced by oral administration of N-butyl-N-(4-hydroxybutyl) nitrosamine, during 10, 15 and 20 weeks. Simple hyperplasia and squamous metaplasia showed a similar E-cadherin pattern when compared with normal urothelium, with its expression confined to cell membrane. Thirty eight percent of the nodular hyperplasia, 41.4% of the dysplasia and 100% of the papillomas showed a weak E-cadherin expression. All papillary neoplasm of low malignant potential, low-and high-grade papillary carcinoma, and invasive carcinoma revealed an abnormal staining pattern with an increase in cytoplasm reactivity and discontinuous cell membrane positivity. The loss of expression for low-grade papillary carcinoma versus simple hyperplasia, nodular hyperplasia and dysplasia was statistically significant (p = 0.0001, p = 0.007 and p=0.008, respectively). There was a similar decrease in E-cadherin expression for papillary neoplasm of low malignant potential versus simple hyperplasia, nodular hyperplasia and dysplasia (p = 0.0001; p = 0.001 and p=0.0001, respectively). These results suggest that alteration in the expression of this adhesion molecule in rat may be indicative of tumour progression in N-butyl-N-(4-hydroxybutyl) nitrosamine-induced bladder cancer.
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Loth K, Abergel D, Pelupessy P, Delarue M, Lopes P, Ouazzani J, Duclert-Savatier N, Nilges M, Bodenhausen G, Stoven V. Determination of dihedral Ψ angles in large proteins by combining NHN/CαHα dipole/dipole cross-correlation and chemical shifts. Proteins 2006; 64:931-9. [PMID: 16786593 DOI: 10.1002/prot.21063] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We propose a strategy based on the combination of experimental NH(N)/C(alpha)H(alpha) dipole/dipole cross-correlated relaxation rates and chemical shift analysis for the determination of Psi torsion angles in proteins. The method allows the determination of a dihedral angle that is not easily accessible by nuclear magnetic resonance (NMR). The measurement of dihedral angle restraints can be used for structure calculation, which is known to improve the quality of NMR structures. The method is of particular interest in the case of large proteins, for which spectral assignment of the nuclear Overhauser effect spectra, and therefore straightforward structural determination, is out of reach. One advantage of the method is that it is reasonably simple to implement, and could be used in association with other methods aiming at obtaining structural information on complex systems, such as residual dipolar coupling measurements. An illustrative example is analyzed in the case of the 30-kDa protein 6-phosphogluconolactonase.
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Galmiche L, Coste-Burel M, Lopes P, Phillippe HJ, Laboisse C. The expression of p16 is not correlated with HPV status in CINI. Histopathology 2006; 48:767. [PMID: 16681697 DOI: 10.1111/j.1365-2559.2006.02340.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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