Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 98
Filtrar
Mais filtros

Base de dados
País/Região como assunto
Tipo de documento
Intervalo de ano de publicação
1.
Am J Physiol Regul Integr Comp Physiol ; 326(6): R472-R483, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38557152

RESUMO

The role of muscle mass in modulating performance and perceived fatigability across the entire intensity spectrum during cycling remains unexplored. We hypothesized that at task failure (Tlim), muscle contractile function would decline more following single- (SL) versus double-leg (DL) cycling within severe and extreme intensities, but not moderate and heavy intensities. After DL and SL ramp-incremental tests, on separate days, 11 recreationally active males (V̇o2max: 49.5 ± 7.7 mL·kg-1·min-1) completed SL and DL cycling until Tlim within each intensity domain. Power output for SL trials was set at 60% of the corresponding DL trial. Before and immediately after Tlim, participants performed an isometric maximal voluntary contraction (MVC) coupled with one superimposed and three resting femoral nerve stimulations [100 Hz; 10 Hz; single twitch (Qtw)] to measure performance fatigability. Perceived fatigue, leg pain, dyspnea, and effort were collected during trials. Tlim within each intensity domain was not different between SL and DL (all P > 0.05). MVC declined more for SL versus DL following heavy- (-42 ± 16% vs. -30 ± 18%; P = 0.011) and severe-intensity cycling (-41 ± 12% vs. -31 ± 15%; P = 0.036). Similarly, peak Qtw force declined more for SL following heavy- (-31 ± 12% vs. -22 ± 10%; P = 0.007) and severe-intensity cycling (-49 ± 13% vs. -40 ± 7%; P = 0.048). Except for heavy intensity, voluntary activation reductions were similar between modes. Similarly, except for dyspnea, which was lower for SL versus DL across all domains, ratings of fatigue, pain, and effort were similar at Tlim between exercise modes. Thus, the amount of muscle mass modulates the extent of contractile function impairment in an intensity-dependent manner.NEW & NOTEWORTHY We investigated the modulatory role of muscle mass on performance and perceived fatigability across the entire intensity spectrum. Despite similar time-to-task failure, single-leg cycling resulted in greater impairments in muscle contractile function within the heavy- and severe-intensity domains, but not the moderate- and extreme-intensity domains. Perceived fatigue, pain, and effort were similar between cycling modes. This indicates that the modulatory role of muscle mass on the extent of performance fatigability is intensity domain-dependent.


Assuntos
Ciclismo , Fadiga Muscular , Músculo Esquelético , Humanos , Masculino , Músculo Esquelético/inervação , Músculo Esquelético/fisiologia , Adulto Jovem , Adulto , Percepção/fisiologia , Contração Muscular , Contração Isométrica , Estimulação Elétrica , Esforço Físico
2.
Artigo em Inglês | MEDLINE | ID: mdl-38842514

RESUMO

PURPOSE: To investigate whether a heavy-intensity priming exercise precisely prescribed within the heavy-intensity domain would lead to a greater peak-power output (POpeak) and a longer maximal oxygen uptake (V̇O2max) plateau. METHODS: Twelve recreationally active adults participated in this study. Two visits were required: (i) a step-ramp-step test (RI control), and (ii) a RI-test preceded by a priming exercise within the heavy-intensity domain (RI primed). A piece-wise equation was used to quantify the V̇O2 plateau duration (V̇O2plateau-time). The mean response time (MRT) was computed during the RI control condition. The delta (Δ) V̇O2-slope (S; mL·min-1·W-1) and V̇O2-Y-intercept (Y; mL·min-1) within the moderate-intensity domain between conditions (RI primed minus RI control) was also assessed using a novel graphical analysis. RESULTS: V̇O2plateau-time (P = 0.001; d = 1.27) and POpeak (P = 0.003; d = 1.08) were all greater in the RI Primed. MRT (P < 0.001; d = 2.45) was shorter in the RI primed compared to the RI control. A larger ΔV̇O2plateau-time was correlated with a larger ΔMRT between conditions (r = -0.79; P = 0.002). CONCLUSIONS: This study demonstrated that heavy-intensity priming exercise lengthened the V̇O2plateau-time and increased POpeak. The overall faster RI-V̇O2 responses seem to be responsible for the longer V̇O2plateau-time. Specifically, a shorter MRT, but not changes in RI-V̇O2-slopes, was associated to a longer V̇O2plateau-time following priming exercise.

3.
BMC Ophthalmol ; 24(1): 287, 2024 Jul 16.
Artigo em Inglês | MEDLINE | ID: mdl-39014314

RESUMO

BACKGROUND: To report real-world outcomes of patients with primary Reghmatogenous Retinal Detachment (RRD) treated with Pneumatic Retinopexy (PnR) according to the indications of the Pneumatic Retinopexy versus Vitrectomy for management of Primary Rhegmatogenous Retinal Detachment Outcomes Randomized Trial (PIVOT) trial. METHODS: Multicenter, retrospective study. Patients treated with PnR for RRD between 2021 and 2023 and a follow-up of at least 6 months were included. Single-procedure anatomical success, final anatomical success, complications, causes of failures, best corrected visual acuity (BCVA) after surgery, and the vision-related quality of life using the 25-Item National Eye Institute Visual Function Questionnaire (NEI VFQ-25) were reported. RESULTS: A total of 76 eyes of 76 patients were included. Mean age was 60 ± 8.1 years. Primary anatomic reattachment was achieved by 84.3% of patients and final anatomical reattachment after pars plana vitrectomy was obtained in 100% of patients. BCVA improved from 0.32 (20/40) to 0.04 (20/20) logMar (p < 0.001) at 6 months. The main cause of failure was related to the presence of additional (likely missed) retinal breaks (66.6% of cases). Also, primary PnR failure was more frequent in eyes of patients with older age, macular involvement, worse baseline BCVA, greater extent of the RRD, and increased duration from diagnosis to treatment. Overall, the mean NEI-VFQ 25 composite score was 93.9% ± 6.4 at 6 months. CONCLUSIONS: The criteria of the PIVOT trial can be applied to real-world scenarios in the decision-making process for the treatment of primary RRD, with excellent anatomical and functional outcomes.


Assuntos
Qualidade de Vida , Descolamento Retiniano , Acuidade Visual , Vitrectomia , Humanos , Descolamento Retiniano/cirurgia , Descolamento Retiniano/fisiopatologia , Pessoa de Meia-Idade , Feminino , Masculino , Acuidade Visual/fisiologia , Estudos Retrospectivos , Idoso , Vitrectomia/métodos , Tamponamento Interno/métodos , Seguimentos , Resultado do Tratamento , Fluorocarbonos/administração & dosagem
4.
Eur J Appl Physiol ; 124(7): 2069-2079, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38400931

RESUMO

PURPOSE: Different strategies for near-infrared spectroscopy (NIRS)-derived muscle oxidative capacity assessment have been reported. This study compared and evaluated (I) approaches for averaging trials; (II) NIRS signals and blood volume correction equations; (III) the assessment of vastus lateralis (VL) and tibialis anterior (TA) muscles in two fitness levels groups. METHODS: Thirty-six participants [18 chronically trained (CT: 14 males, 4 females) and 18 untrained (UT: 10 males, 8 females)] participated in this study. Two trials of twenty transient arterial occlusions were performed for NIRS-derived muscle oxidative capacity assessment. Muscle oxygen consumption ( V ˙ O2m) was estimated from deoxygenated hemoglobin (HHb), corrected for blood volume changes following Ryan (HHbR) and Beever (HHbB) equations, and from oxygen saturation (StO2) in VL and TA. RESULTS: Superimposing or averaging V ˙ O2m or averaging the rate constants (k) from the two trials resulted in equivalent k values [two one-sided tests (TOST) procedure with 5% equivalence margin-P < 0.001]. Whereas HHbR (2.35 ± 0.61 min-1) and HHbB (2.34 ± 0.58 min-1) derived k were equivalent (P < 0.001), StO2 derived k (2.81 ± 0.92 min-1) was greater (P < 0.001) than both. k values were greater in CT vs UT in both muscles (VL: + 0.68 min-1, P = 0.002; TA: + 0.43 min-1, P = 0.01). CONCLUSION: Different approaches for averaging trials lead to similar k. HHb and StO2 signals provided different k, although different blood volume corrections did not impact k. Group differences in k were detected in both muscles.


Assuntos
Músculo Esquelético , Consumo de Oxigênio , Espectroscopia de Luz Próxima ao Infravermelho , Humanos , Masculino , Espectroscopia de Luz Próxima ao Infravermelho/métodos , Consumo de Oxigênio/fisiologia , Feminino , Músculo Esquelético/metabolismo , Músculo Esquelético/fisiologia , Adulto , Oxigênio/metabolismo , Oxigênio/sangue , Hemoglobinas/metabolismo
5.
Clin Exp Ophthalmol ; 52(1): 42-53, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-37983671

RESUMO

BACKGROUND: This study aimed to evaluate the impact of PreserFlo Microshunt on the ocular surface, focusing on both objective and subjective parameters. METHODS: Prospective-observational study on 48 eyes undergoing PreserFlo Microshunt implantation, standalone or combined with phacoemulsification. At baseline, 1-month, 6-months and 12-months post-operative follow-ups, we performed Ocular Surface Disease Index (OSDI) questionnaire, Schirmer's test (ST), Tear-film break-up time (TBUT), fluoresceine staining (FS), tear osmolarity and minimum corneal epithelial thickness (Epi-ThkMIN. ) measurements. RESULTS: OSDI score improved from 37.43 ± 17.49 at baseline, to 24.13 ± 12.55 at 1-month (p = 0.003) and to 12.89 ± 8.54 and 13.09 ± 10.22 at 6-months and 12-months (p < 0.0001). TBUT and ST, in a similar way, non-significantly increased at 1-month, but then improved at 6-months and 12-months (p < 0.05 for both). Tear osmolarity significantly decreased from 308.2 ± 7.3 mOsm/L at baseline, to 303.3 ± 8.2 mOsm/L, 295.6.2 ± 7.0 mOsm/L and 297.6 ± 6.8 mOsm/L at 1-month, 6-months and 12-months (p < 0.05 for all). Epi-ThkMIN was stable when comparing baseline (44.9 ± 5.7 µm) and 1-month (p = 0.28), and successively increased in 6-months (47.8 ± 5.5 µm, p = 0.02) and 12-months (48.0 ± 3.6 µm, p = 0.01). In subgroup analysis, OSDI score and tear osmolarity were significantly higher at 1-month in combined group compared to standalone group (p = 0.03 and p = 0.02, respectively), but reaching comparable values in successive follow-ups. Further, Oxford scale grades for FS were significantly improved when comparing baseline-6-months and baseline-12-months. CONCLUSION: PreserFlo implantation improved ocular surface subjective symptoms, increased TBUT and ST, and reduced FS, highlighting the potential benefits of this surgical intervention. Moreover, we reported significant improvements of tear osmolarity and corneal epithelium.


Assuntos
Síndromes do Olho Seco , Humanos , Síndromes do Olho Seco/diagnóstico , Síndromes do Olho Seco/cirurgia , Estudos Prospectivos , Qualidade de Vida , Lágrimas , Fluoresceína , Concentração Osmolar
6.
BMC Ophthalmol ; 23(1): 383, 2023 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-37743488

RESUMO

BACKGROUND: To report a case of sutureless scleral-fixated hydrophilic intraocular lens (FIL SSF IOL, Soleko, Italy) opacification following pars plana vitrectomy surgery using sulfur hexafluoride (SF6) for traumatic lens luxation associated with retinal detachment. CASE PRESENTATION: A 77-year-old woman was referred to our emergency department after blunt trauma in her right eye. At the ophthalmic evaluation, visual acuity was hand movement, biomicroscopy showed pseudoexfoliation syndrome and a traumatic lens luxation in the vitreous chamber. The patient underwent pars plana vitrectomy, subluxated cataract explantation, and FIL SSF IOL implant. During surgery, an inferior retinal detachment was encountered, requiring 20% SF6 gas tamponade. No adverse events were encountered. One month postoperatively, visual acuity (BCVA) improved to 0,3 logMAR. At the 3-month follow-up, the patient presented with BCVA of 0,5 logMAR, and biomicroscopy showed a minimal IOL opacification. Six months postoperatively, BCVA decreased to 1.0 logMAR, and diffuse, IOL opacification was noted at slit lamp examination. The patient refused any other surgical intervention for IOL exchange. CONCLUSIONS: Although hydrophilic IOL opacification gas related is known, to the best of our knowledge, this is the first case reported in the literature of FIL SSF IOL opacification after pars plana vitrectomy with gas tamponade for retinal detachment.


Assuntos
Traumatismos Oculares , Lentes Intraoculares , Descolamento Retiniano , Humanos , Feminino , Idoso , Descolamento Retiniano/etiologia , Descolamento Retiniano/cirurgia , Vitrectomia/efeitos adversos , Traumatismos Oculares/complicações , Traumatismos Oculares/cirurgia , Complicações Pós-Operatórias , Segmento Anterior do Olho , Lentes Intraoculares/efeitos adversos
7.
Ophthalmologica ; 246(5-6): 255-277, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37660688

RESUMO

Suprachoroidal hemorrhage (SCH) refers to the accumulation of blood in the suprachoroidal space, a relatively uncommon but significant complication that can occur spontaneously, during ophthalmic surgery, or as a consequence of ocular trauma. If left undiagnosed and untreated, SCH can lead to severe vision loss or even blindness. Therefore, it is crucial for ophthalmologists to have a thorough understanding of this complication, taking proactive measures to prevent it during surgery and being knowledgeable about effective management strategies for patients with SCH. This review article aimed to provide a comprehensive overview of SCH, covering its risk factors, diagnostic approaches, and the best practices for its management. By enhancing awareness and knowledge in this area, we can improve patient outcomes and minimize the impact of SCH in ophthalmic practice.


Assuntos
Hemorragia da Coroide , Oftalmologia , Humanos , Hemorragia da Coroide/diagnóstico , Hemorragia da Coroide/etiologia , Hemorragia da Coroide/cirurgia , Vitrectomia/efeitos adversos , Fatores de Risco , Acuidade Visual
8.
J Sports Sci ; 41(10): 1025-1032, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37722819

RESUMO

The metabolic rate (VO2) at the maximal metabolic steady state (MMSS) is generally not different from the VO2 at the respiratory compensation point (RCP). Based on this, it is often assumed that the heart rate (HR) at RCP would also be similar to that at MMSS. The study aims to compare the HR at RCP with that at MMSS. Seventeen individuals completed a ramp-incremental test, a series of severe-intensity trials to estimate critical power and two-to-three 30-min trials to confirm MMSS. The HR at RCP was retrieved by linear interpolation of the ramp-VO2/HR relationship and compared to the HR at MMSS recorded at 10, 15, 20, 25 and 30 min. The HR at RCP was 166 ± 12 bpm. The HR during MMSS at the timepoints of interest was 168 ± 8, 171 ± 8, 175 ± 9, 177 ± 9 and 178 ± 10 bpm. The HR at RCP was not different from the HR at MMSS at 10 min (P > 0.05) but lower at subsequent timepoints (P < 0.05) with this difference becoming progressively larger. For all timepoints, limits of agreement were large (~30 bpm). Given these differences and the variability at the individual level, the HR at RCP cannot be used to control the metabolic stimulus of endurance exercise.


Assuntos
Consumo de Oxigênio , Troca Gasosa Pulmonar , Humanos , Consumo de Oxigênio/fisiologia , Frequência Cardíaca , Troca Gasosa Pulmonar/fisiologia , Teste de Esforço
9.
Graefes Arch Clin Exp Ophthalmol ; 260(2): 545-551, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34487226

RESUMO

PURPOSE: To report the preliminary results of gonioscopy-assisted transluminal trabeculotomy (GATT) in eyes with chronic angle-closure glaucoma (CACG). METHODS: Retrospective, single-center, case series of GATT procedures is performed on patients with CACG. The primary outcome was intraocular pressure (IOP). Success was defined as IOP reduction >30% from baseline at 6 and 12 months with (qualified) or without (complete) glaucoma medication. Secondary outcomes were best-corrected visual acuity (BCVA), visual field (VF), peripheral anterior synechiae (PAS), medications, and complications. RESULTS: Fifteen eyes (15 patients) with a minimum follow-up of 1 year were included for the analysis. Preoperatively, the mean (±SD) IOP was 30.27 (±4.20) mmHg and 15.20 (±2.08) mmHg at 1 year postoperatively (p<0.001). The mean (±SD) percentage of IOP reduction from baseline was 49% (±9.41). At 6 and 12 months, the success rate complete and qualified was 93% (73% and 20%) and 100% (73% and 27%), respectively. BCVA and VF mean deviation were comparable before and after surgery (p=0.167 and p= 0.710, respectively). The median (range) number of glaucoma drugs decreased from 3 (3-4) before to 0 (0-2) after GATT (p<0.001). The absence of PAS was observed in 80% of patients after surgery. Transient hyphema was a common complication requiring aspiration in one case. CONCLUSION: At 12 months of follow-up, our preliminary results indicate that GATT in CACG effectively reduces the IOP and the number of medication with a low risk of complications. Following ab interno trabeculotomy, an open-angle without PAS was achieved in the majority of patients. TRIAL REGISTRATION NUMBER: nr. 2016/0010904.


Assuntos
Glaucoma de Ângulo Fechado , Glaucoma de Ângulo Aberto , Trabeculectomia , Seguimentos , Glaucoma de Ângulo Fechado/diagnóstico , Glaucoma de Ângulo Fechado/cirurgia , Glaucoma de Ângulo Aberto/cirurgia , Gonioscopia , Humanos , Pressão Intraocular , Estudos Retrospectivos , Resultado do Tratamento
10.
BMC Ophthalmol ; 22(1): 59, 2022 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-35135528

RESUMO

BACKGROUND: To report a case of malignant glaucoma that developed after gonioscopy-assisted transluminal trabeculotomy (GATT). CASE PRESENTATION: An 85-year-old male pseudophakic patient affected by pseudoexfoliative glaucoma (PEXG), unresponsive to medical glaucoma treatment, underwent uneventful GATT surgery. On the first day after surgery, the eye showed a shallow central and peripheral anterior chamber (AC) with a raised intraocular pressure (IOP) measured at 55 mmHg. Optical coherence tomography and ultrasound biomicroscopy confirmed the diagnosis of malignant glaucoma. Laser iridotomy, posterior capsulotomy and hyaloidotomy were performed, and the patient was treated with atropine sulphate 1%, maximum topical and systemic ocular hypotensive drugs with no improvement in the IOP. Subsequently, the patient underwent pars plana anterior vitrectomy, resulting in deepening of the AC with opening of the iridocorneal angle and decrease of the IOP. No further postoperative complications were recorded, and the IOP remained controlled 12 months after surgery without antiglaucoma medications. CONCLUSIONS: Despite the minimally invasive profile of GATT, malignant glaucoma may develop after this procedure. Early recognition and prompt treatment are mandatory for preventing permanent visual loss.


Assuntos
Glaucoma de Ângulo Aberto , Glaucoma , Trabeculectomia , Idoso de 80 Anos ou mais , Câmara Anterior , Seguimentos , Glaucoma/etiologia , Glaucoma/cirurgia , Glaucoma de Ângulo Aberto/cirurgia , Gonioscopia , Humanos , Pressão Intraocular , Masculino , Estudos Retrospectivos , Trabeculectomia/efeitos adversos , Resultado do Tratamento
11.
Am J Physiol Regul Integr Comp Physiol ; 321(2): R238-R249, 2021 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-34189949

RESUMO

Neuromuscular (NM), cardiorespiratory, and perceptual responses to maximal-graded exercise using different amounts of active muscle mass remain unclear. We hypothesized that during dynamic exercise, peripheral NM fatigue (declined twitch force) and muscle pain would be greater using smaller muscle mass, whereas central fatigue (declined voluntary activation) and ventilatory variables would be greater using larger muscle mass. Twelve males (29.8 ± 4.7 years) performed two ramp-incremental cycling tests until task failure: 1) single-leg (SL) with 10 W·min-1 ramp and 2) double-leg (DL) with 20 W·min-1 ramp. NM fatigue was assessed at baseline, task failure (post), and after 1, 4, and 8 min of recovery. Cardiorespiratory and perceptual variables [i.e., ratings of perceived exertion (RPE), pain, and dyspnea] were measured throughout cycling. Exercise duration was similar between sessions (SL: 857.7 ± 263.6 s; DL: 855.0 ± 218.8 s; P = 0.923), and higher absolute peak power output was attained in DL (SL: 163.2 ± 43.8 W; DL: 307.0 ± 72.0 W; P < 0.001). Although central fatigue did not differ between conditions (SL: -6.6 ± 6.5%; DL: -3.5 ± 4.8%; P = 0.091), maximal voluntary contraction (SL: -41.6 ± 10.9%; DL: -33.7 ± 8.5%; P = 0.032) and single twitch forces (SL: -59.4 ± 18.8%; DL: -46.2 ± 16.2%; P = 0.003) declined more following SL. DL elicited higher peak oxygen uptake (SL: 42.1 ± 10.0 mL·kg-1·min-1; DL: 50.3 ± 9.3 mL·kg-1·min-1; P < 0.001), ventilation (SL: 137.1 ± 38.1 L·min-1; DL: 171.5 ± 33.2 L·min-1; P < 0.001), and heart rate (SL: 167 ± 21 bpm; DL: 187 ± 8 bpm; P = 0.005). Dyspnea (P = 0.025) was higher in DL; however, RPE (P = 0.005) and pain (P < 0.001) were higher in SL. These results suggest that interplay between NM, cardiorespiratory, and perceptual determinants of exercise performance during ramp-incremental cycling to task failure is muscle mass dependent.


Assuntos
Ciclismo , Aptidão Cardiorrespiratória , Contração Muscular , Fadiga Muscular , Músculo Esquelético/inervação , Resistência Física , Potenciais de Ação , Adulto , Humanos , Masculino , Mialgia/etiologia , Mialgia/fisiopatologia , Fatores de Tempo , Volição
12.
Graefes Arch Clin Exp Ophthalmol ; 259(1): 257-262, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32529278

RESUMO

PURPOSE: To report a retrospective series of patients implanted with a novel hydrophilic acrylic single-piece intraocular lens (IOL) designed for sutureless scleral fixation (FIL-SSF Carlevale lens, Soleko, Italy) injectable through a 2.2-mm incision. METHODS: Seventy-eight patients with minimum 6-month follow-up were divided into 6 groups: dropped nucleus, luxated IOL, trauma, aphakia, IOL exchange, and Marfan's syndrome. Surgery included peritomy and scleral flap creation at 3 and 9 o'clock position. The IOL was then injected and grasped with 25G forceps through a hole created 2 mm posterior to the limbus underneath the sculped scleral flap. RESULTS: The study included 78 patients (mean age 71.9 ± 12.6 years) and average follow-up 10.2 ± 4.2 months. Average surgery duration was 69.4 ± 26.1 min and vision significantly improved from 0.86 ± 0.56 logMAR to 0.38 ± 0.42 logMAR at 6 months post-operative (p < 0.001). Intraoperative complications included corneal edema, retinal tears, and vitreous bleeding each in 2/78 patients (2.5%); 1/78 (1.3%) localized retinal detachment and 1/78 (1.3%) rupture of one T-shaped IOL harpoon. Post-operative complications included 4/78 (5.1%) cystoid macular edemas, 2/78 retinal tears, 2/78 retinal detachments, 2/78 developed ocular hypertension, and 1/78 corneal decompensation requiring DSAEK. CONCLUSION: The Carlevale lens is designed for sutureless intrascleral fixation and can be successfully used in a variety of indications including difficult trauma cases with good rehabilitation. An implant requires experience and delicate manipulation.


Assuntos
Implante de Lente Intraocular , Lentes Intraoculares , Idoso , Humanos , Estudos Retrospectivos , Esclera/cirurgia , Técnicas de Sutura , Acuidade Visual
13.
Eur J Appl Physiol ; 121(7): 1921-1931, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-33730210

RESUMO

PURPOSE: This study evaluated (i) the relationship between oxygen uptake ([Formula: see text]O2) kinetics and maximal [Formula: see text]O2 ([Formula: see text]O2max) within groups differing in fitness status, and (ii) the adjustment of [Formula: see text]O2 kinetics compared to that of central [cardiac output (Q̇), heart rate (HR)] and peripheral (deoxyhemoglobin over [Formula: see text]O2 ratio ([HHb]/[Formula: see text]O2)] O2 delivery, during step-transitions to moderate-intensity exercise. METHODS: Thirty-six young healthy male participants (18 untrained; 18 trained) performed a ramp-incremental test to exhaustion and 3 step-transitions to moderate-intensity exercise. Q̇ and HR kinetics were measured in 18 participants (9 untrained; 9 trained). RESULTS: No significant correlation between τ̇[Formula: see text]O2 and [Formula: see text]O2max was found in trained participants (r = 0.29; p > 0.05) whereas a significant negative correlation was found in untrained (r = - 0.58; p < 0.05) and all participants (r = - 0.82; p < 0.05). τQ̇ (18.8 ± 5.5 s) and τHR (20.1 ± 6.2 s) were significantly greater than τ[Formula: see text]O2 (13.9 ± 2.7 s) for trained (p < 0.05). No differences were found between τQ̇ (22.8 ± 8.45 s), τHR (21.2 ± 8.3 s) and τ[Formula: see text]O2 (28.9 ± 5.7 s) for untrained (p > 0.05). τQ̇ demonstrated a significant strong positive correlation with τHR in trained (r = 0.76; p < 0.05) but not untrained (r = 0.61; p > 0.05). A significant overshoot in the [HHb]/[Formula: see text]O2 ratio was found in the untrained groups (p < 0.05) but not in the trained groups (p > 0.05) CONCLUSION: The results indicated that when comparing participants of different fitness status (i) there is a point at which greater V̇O2max values are not accompanied by faster [Formula: see text]O2 kinetics; (ii) central delivery of O2 does not seem to limit the kinetics of [Formula: see text]O2; and (iii) O2 delivery within the active tissues might contribute to the slower [Formula: see text]O2 kinetics response in untrained participants.


Assuntos
Consumo de Oxigênio/fisiologia , Aptidão Física/fisiologia , Adulto , Débito Cardíaco/fisiologia , Teste de Esforço , Frequência Cardíaca/fisiologia , Humanos , Masculino
14.
Int Ophthalmol ; 41(6): 2293-2300, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33745035

RESUMO

PURPOSE: To review the current adoption of laser flare and cell photometry (LFCP) in the setting of modern cataract surgery to analyze inflammation aiming to identify evidence of a correlation between LFCP values and the risk of cystoid macular edema (CME) development. METHODS: An extensive PubMed literature search was performed to review all the published studies investigating inflammation by LFCP after uncomplicated phacoemulsification. The following keywords were used: cataract surgery, cystoid macular edema, anterior chamber inflammation, laser flare, and cell photometry. RESULTS: Seventy-eight original articles investigating inflammation by LFCP were selected. Macula alterations were searched in 12 (15%) trials, by optical coherence tomography or fluorescein angiography in 11 (14%) and 1 (1%) studies, respectively. Among them, 9 (12%) papers investigated the correlation between LFCP values and cystic changes to the macula: 7 (9%) and 2 (3%) studies identified a positive and negative correlation, respectively. Three (4%) papers did not perform any correlation analysis. CONCLUSION: CME, as a consequence of uncontrolled postoperative inflammation, is a common cause for unfavorable visual outcomes following uncomplicated phacoemulsification with IOL implantation. After surgery, intraocular inflammation is generally assessed by qualitative methods. Although well-established and practical in uveitis, they are inadequate to detect the modest inflammatory response that usually occurs after uneventful phacoemulsification. LFCP correlate with the chance of macula alteration after surgery and higher the values higher the risk of CME. The quantitative analysis of intraocular inflammation by LFCP after cataract surgery might be a tool to predict the risk of pseudophakic CME.


Assuntos
Catarata , Edema Macular , Facoemulsificação , Humanos , Inflamação/diagnóstico , Inflamação/etiologia , Lasers , Edema Macular/diagnóstico , Edema Macular/epidemiologia , Edema Macular/etiologia , Facoemulsificação/efeitos adversos , Fotometria , Complicações Pós-Operatórias/diagnóstico , Complicações Pós-Operatórias/etiologia , Tomografia de Coerência Óptica
15.
J Physiol ; 598(2): 285-302, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826296

RESUMO

KEY POINTS: Fatigue and muscle pain induced in a remote muscle group has been shown to alter neuromuscular performance in exercising muscles. Inhibitory neural feedback associated with activation of mechano- and metabo-sensitive muscle afferents has been implicated in this phenomenon. The present study aimed to quantify and compare the effects of pre-induced fatigue and concurrent rising pain (evoked by muscle ischaemia) on the contralateral leg exercise capacity, neuromuscular performance, and corticomotor excitability and inhibition of knee extensor muscles. Pre-induced fatigue in one leg had a greater detrimental effect than the concurrent rising pain on the contralateral limb cycling capacity. Furthermore, pre-induced fatigue, but not concurrent rising pain, reduced corticospinal inhibition recorded from tested contralateral muscles. Regardless of the origin or mechanisms modulating sensory afferents during single-leg cycling exercise (i.e. pre-induced fatigue vs. concurrent rising pain), the limit of exercise tolerance remained the same and exercise was terminated upon achievement of a sensory tolerance limit. ABSTRACT: Individuals often need to maintain voluntary contractions during high intensity exercise in the presence of fatigue and pain. This investigation examined the effects of pre-induced fatigue and concurrent rising pain (evoked by muscle ischaemia) in one leg on motor fatigability and corticospinal excitability/inhibition of the contralateral limb. Twelve healthy males undertook four experimental protocols including unilateral cycling to task failure at 80% of peak power output with: (i) the right-leg (RL); (ii) the left-leg (LL); (iii) RL immediately preceded by LL protocol (FAT-RL); and (iv) RL when blood flow was occluded in the contralateral (left) leg (PAIN-RL). Participants performed maximal and submaximal 5 s right-leg knee extensions during which transcranial magnetic and femoral nerve electrical stimuli were delivered to elicit motor-evoked and compound muscle action potentials, respectively. The pre-induced fatigue reduced the right leg cycling time-to-task failure (mean ± SD; 332 ± 137 s) to a greater extent than concurrent pain (460 ± 158 s), compared to RL (580 ± 226 s) (P < 0.001). The maximum voluntary contraction force declined less following FAT-RL (P < 0.019) and PAIN-RL (P < 0.032) compared to RL. Voluntary activation declined and the corticospinal excitability recorded from knee extensors increased similarly after the three conditions (P < 0.05). However, the pre-induced fatigue, but not concurrent pain, reduced corticospinal inhibition compared to RL (P < 0.05). These findings suggest that regardless of the origin and/or mechanisms modulating sensory afferent feedback during single-leg cycling (e.g. pre-induced fatigue vs. concurrent rising pain), the limit of exercise tolerance remains the same, suggesting that exercise will be terminated upon achievement of sensory tolerance limit.


Assuntos
Tolerância ao Exercício , Fadiga Muscular , Músculo Esquelético/fisiopatologia , Dor/fisiopatologia , Vias Aferentes , Eletromiografia , Potencial Evocado Motor , Retroalimentação Fisiológica , Humanos , Masculino , Contração Muscular , Estimulação Magnética Transcraniana
16.
Am J Physiol Regul Integr Comp Physiol ; 319(3): R315-R322, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32697652

RESUMO

During exhaustive ramp-incremental cycling tests, the incidence of O2 uptake (V̇o2) plateaus is low. To verify the attainment of maximum V̇o2 (V̇o2max), it is recommended that a trial at a power output (PO) corresponding to 110% of the ramp-derived peak (POpeak) is performed. It remains unclear whether verification trials set at this PO can be tolerated for long enough to allow attainment of V̇o2max. Eleven recreationally trained individuals performed five ramp tests of varying slope (5, 10, 15, 25, and 30 W/min), each followed, in series, by two verification trials: the first at 110% POpeak of the 25 W/min ramp and the second at 110% POpeak attained in the preceding ramp test. Exercise duration of the first verification trial was on average 81 ± 15 s (CV = 9 ± 3%) versus 162 ± 32, 121 ± 24, 103 ± 15, and 73 ± 10 s for the second verification trials at 110% of POpeak of the 5, 10, 15, and 30 W/min ramp tests, respectively (P < 0.05). Compared with the highest V̇o2 recorded during ramp tests, V̇o2 from the subsequent verification trials was not different for the 5, 10, and 15 W/min ramp tests (P > 0.05) but was lower for the 25 and 30 W/min ramp tests (P < 0.05). Verification trials at 110% POpeak of rapidly incrementing ramp tests (i.e., 25 W/min) were not sustained for long enough to allow the attainment of V̇o2max. With commonly used rapidly incrementing ramp tests engendering exhaustion within 8-12 min, verification trials less than POpeak should be preferred as they can be sustained sufficiently long to allow the attainment of V̇o2max.


Assuntos
Transporte Biológico/fisiologia , Exercício Físico/fisiologia , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologia , Adulto , Teste de Esforço/métodos , Frequência Cardíaca/fisiologia , Humanos , Masculino
17.
Am J Physiol Regul Integr Comp Physiol ; 318(2): R399-R409, 2020 02 01.
Artigo em Inglês | MEDLINE | ID: mdl-31850819

RESUMO

During ramp-incremental (RI) exercise to exhaustion, the near-infrared spectroscopy-derived deoxygenated hemoglobin ([HHb]) signal in the vastus lateralis muscle shows a linear increase up to a point at which a plateau-like response is manifested ([HHb]bp). This study investigated if 1) the [HHb]bp is affected by different fractions of inspired O2 (FIO2) [hypoxia (16%; HYPO); normoxia (21%; NORM); hyperoxia (30%; HYPER)]; and 2) an abrupt change to hyperoxic-inspired gas just before the occurrence of the [HHb]bp (HYPERSWITCH) would affect the [HHb] plateau-like response. Ten physically active male participants reported to the laboratory on four separate occasions to perform an RI test to exhaustion in NORM, HYPO, and HYPER and an RI test to exhaustion with an abrupt increase in FIO2 (30%; HYPERSWITCH) 15 W before the power output (PO) associated with [HHb]bp in normoxia. PO, [HHb], tissue O2 (StO2), and pulse O2 saturation (SpO2) were recorded continuously. Peak PO was significantly lower in HYPO (290 ± 21 W) and higher in HYPER (321 ± 22 W) and HYPERSWITCH (320 ± 19 W) compared with NORM (311 ± 18 W). The PO associated with [HHb]bp was not different between NORM and HYPER (246 ± 23 vs. 247 ± 24 W), but it was lower in HYPO (198 ± 31 W) than NORM and HYPER. The PO associated with the [HHb]bp in HYPERSWITCH (240 ± 23) was not different compared with NORM. HYPER and HYPERSWITCH resulted in greater StO2 and SpO2 compared with NORM. These results suggest that the [HHb]bp response is not dependent of O2 driving pressure and that other physiological mechanisms might determine its occurrence.


Assuntos
Hemoglobinas/metabolismo , Inalação , Contração Muscular , Fadiga Muscular , Consumo de Oxigênio , Oxigênio/sangue , Músculo Quadríceps/irrigação sanguínea , Músculo Quadríceps/metabolismo , Espectroscopia de Luz Próxima ao Infravermelho , Adulto , Ciclismo , Biomarcadores/sangue , Humanos , Hiperóxia/sangue , Hiperóxia/fisiopatologia , Hipóxia/sangue , Hipóxia/fisiopatologia , Masculino , Valor Preditivo dos Testes , Distribuição Aleatória , Fatores de Tempo , Adulto Jovem
18.
Graefes Arch Clin Exp Ophthalmol ; 258(12): 2629-2638, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32910308

RESUMO

BACKGROUND: The classification of macular hole closure patterns (MHCPs) currently relies on time domain OCT allowing only "open" and "closed" statuses or is based on inner foveal contour shape. Both classification types give no information on retinal layer reconstitution. Novel sophisticated surgical techniques lead to previously unknown MHCPs, outdating existing classifications and urging new ones. The purpose of the present study is to introduce a new classification allowing proper description of all MHCPs resulting from newer surgeries and based on the restoration of retinal layers. METHODS: Retrospective analysis of patients undergoing MH surgery with five different surgical techniques was performed. MHCPs were classified according to spectral domain optical coherence tomography (SD-OCT). Type 0: open MH (0A: flat margin, 0B: elevated, 0C: oedematous); type 1: closed MHs (1A: reconstitution all retinal layers; 1B interruption of the external layers; 1C interruption of internal layers); type 2: MH closed with autologous or heterologous filling tissue interrupting the normal foveal layered anatomy (2A: filling tissue through all layers; 2B reconstitution of normal inner retinal layers; 2C reconstitution of normal outer retinal layers; 2D H-shaped bridging of filling tissue). RESULTS: Closure rate was 95.2% (241/253). Surgical technique and vision correlated to closure pattern (p < 0.001). Type 1 MHCPs had the best post-operative visual acuity (VA) compared with type 2 and type 0 (p < 0.001). MHCPs 1A and 1C performed better than all others. MHCP at months 1 and 3 changed in 42/254 (16.5%) and remained stable in 212/254 (83.5%). Improvement in vision was higher in eyes with shifting closure pattern (0.57 ± 0.33 vs 0.51 ± 0.48 logMAR; p 0.021). CONCLUSION: MHCP classification based on retinal layer restoration properly comprises post-operative anatomic morphologies. MHCPs correlate the surgical technique and post-operative visual outcomes.


Assuntos
Perfurações Retinianas , Membrana Basal , Fóvea Central , Humanos , Perfurações Retinianas/diagnóstico , Perfurações Retinianas/cirurgia , Estudos Retrospectivos , Tomografia de Coerência Óptica , Vitrectomia
19.
Retina ; 40(10): 1955-1963, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31834129

RESUMO

PURPOSE: To investigate the role of an internal limiting membrane (ILM) flap in macular hole (MH) surgery on closure rate, visual acuity, and integrity of the outer retinal layers. METHODS: Retrospective, nonrandomized interventional analysis in which 117 eyes of 117 patients were included who had undergone pars-plana vitrectomy (PPV) and gas tamponade for primary idiopathic MH >400 µm with either conventional ILM peeling or with inverted ILM flap technique at The Royal Liverpool University Hospital between January 2016 and April 2018. Main outcome measures were closure of MH, best-corrected visual acuity (BCVA) at 3, 6, and 12 months, and restoration of external limiting membrane and ellipsoid zone (EZ) using optical coherence tomography. RESULTS: Macular hole closure rate was significantly higher in patients with an ILM flap (67/68; 98.53%) than in those with conventional ILM peeling (43/49; 87.76%) (P = 0.02). Both groups showed significant improvements in their preoperative to postoperative BCVA at 3 months from 1.07 (0.43) logarithm of the minimum angle of resolution (logMAR) (20/235 Snellen) to 0.71 (0.34) logMAR (20/103 Snellen) (P <0.001), but there was no significant difference between the two groups (P = 0.45, P = 0.71). We found significant associations between postoperative BCVA and preoperative BCVA (P < 0.01) and the integrity of the EZ (P < 0.01). In 35 patients who had follow-up to 12 months, there was a significant improvement in BCVA between 3, 6, and 12 months from 0.73 (0.45) logMAR (20/107 Snellen) to 0.53 (0.24) logMAR (20/68 Snellen) and to 0.35 (0.18) logMAR (20/45 Snellen), respectively (P < 0.01). There was no significant difference at these time periods between the two groups (P = 0.62, P = 0.21, P = 0.31). The integrity of the EZ also improved significantly between 3, 6, and 12 months (P = 0.01), irrespective of the presence of an ILM flap (P = 0.58), but with a trend toward delay in restoration in those patients with an ILM flap. The improvement in BCVA at 12 months, taking into account the age of the patient, size and duration of the MH, presence of an ILM flap, and preoperative BCVA was dependent on the state of the EZ (P = 0.01). CONCLUSION: In patients undergoing primary pars-plana vitrectomy for MH >400 µm, the presence of an inverted ILM flap was associated with a significantly higher closure rate than a conventional ILM peeling. Best-corrected visual acuity showed a strong correlation with the integrity of the EZ and both improved significantly between 3, 6, and 12 months, irrespective of the presence of an ILM flap.


Assuntos
Membrana Basal/cirurgia , Retina/fisiopatologia , Perfurações Retinianas/cirurgia , Retalhos Cirúrgicos , Acuidade Visual/fisiologia , Idoso , Tamponamento Interno , Feminino , Fluorocarbonos/administração & dosagem , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Decúbito Ventral , Retina/diagnóstico por imagem , Perfurações Retinianas/fisiopatologia , Estudos Retrospectivos , Tomografia de Coerência Óptica , Vitrectomia
20.
Scand J Med Sci Sports ; 30(3): 472-484, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31663173

RESUMO

To examine whether the menstrual or monophasic oral contraceptive cycle phases affect submaximal (oxygen uptake ( V ˙ O2 ) kinetics, maximal lactate steady-state (MLSS)) and maximal ( V ˙ O2max , time-to-exhaustion (TTE)) responses to exercise in healthy, active women. During the mid-follicular or inactive-pill phase and the mid-luteal or active-pill phase of the respective menstrual or oral contraceptive cycle, 15 non-oral contraceptive users (mean and standard deviation (SD) (±): 27 ± 6 years; 171 ± 5 cm; 65 ± 7 kg) and 15 monophasic oral contraceptive users (24 ± 4 years; 169 ± 10 cm; 68 ± 10 kg) performed: one V ˙ O2 kinetics test; one ramp-incremental test; two to three 30-minute constant-load cycling trials to determine the power output corresponding to MLSS (MLSSp ), followed by a TTE trial. The phase of the menstrual or oral contraceptive cycle did not affect the time constant of the V ˙ O2 kinetics response (τ V ˙ O2 ) (mid-follicular, 20 ± 5 seconds and mid-luteal, 18 ± 3 seconds; inactive-pill, 22 ± 8 seconds and active-pill, 23 ± 6 seconds), V ˙ O2max (mid-follicular, 3.06 ± 0.32 L min-1 and mid-luteal, 3.00 ± 0.33 L min-1 ; inactive-pill, 2.87 ± 0.39 L min-1 and active-pill, 2.87 ± 0.45 L min-1 ), MLSSp (mid-follicular, 181 ± 30 W and mid-luteal, 182 ± 29 W; inactive-pill, 155 ± 26 W and active-pill, 155 ± 27 W), and TTE (mid-follicular, 147 ± 42 seconds and mid-luteal, 128 ± 54 seconds; inactive-pill, 146 ± 70 seconds and active-pill, 139 ± 77 seconds) (P > .05). The rate of perceived exertion (RPE) at minute 30 of the MLSSp trials was greater in the mid-follicular phase (6.2 ± 1.5) compared with the mid-luteal phase (5.3 ± 1.4) for non-oral contraceptive users (P = .022). The hormonal fluctuations between the menstrual and oral contraceptive cycle phases had no detectable effects on submaximal and maximal exercise performance, even when RPE differed.


Assuntos
Desempenho Atlético , Anticoncepcionais Orais/farmacologia , Exercício Físico , Ciclo Menstrual , Adulto , Feminino , Humanos , Ácido Láctico/sangue , Consumo de Oxigênio , Adulto Jovem
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa