Utility guideline and considerations for the novel Hugo™ RAS (robotic-assisted surgery) system in colorectal surgery: surgical outcomes and initial experience in a tertiary center.

PURPOSE: A novel robotic platform-Hugo™ RAS (robotic-assisted surgery) system-has been introduced with several innovations that may prove advantageous for surgeons, such as an open console and four interchangeable modular arms. Our study aims to evaluate this platform's safety, efficacy, and potential impact on the surgical treatment of colorectal pathology. METHODS: Patients underwent robotic-assisted colorectal procedures with the Hugo™ RAS system at the General University Hospital of Elche from October 2023 to July 2024. Patient characteristics, intraoperative and postoperative variables, and robotic technical issues were recorded. RESULTS: Forty consecutive patients were included (14 right, 13 left, and 8 rectum neoplasms; 4 left diverticulitis; and 1 ileocecal Crohn's disease). The patients' characteristics were as follows: median age, 69.5 years; 24 males and 16 females; 45% ASA III-IV; and Charlson Comorbidity Index > 5:42.5%. We recorded four medical (2 anemia, 1 phlebitis, and 1 admission to the intensive care unit) and three surgical (1 hematoma of the incision, 1 intestinal occlusion, and 1 dehiscence of the anastomosis) postoperative complications. We had no conversions neither open nor laparoscopic surgery. The average hospital stay was 3 days, with no mortality or readmission. CONCLUSIONS: The Hugo™ RAS system is safe and feasible for colorectal procedures. The modularity of the arms provides the versatility of configurations adjusted depending on the patient's body features and the surgeon's preferences and greater adaptability to operating rooms. The open console is highly comfortable and ergonomic for the surgeon, allowing communication with the operating room environment. TRIAL REGISTRATION: NCT06512480.

Changes in the Activity of the Erector Spinae and Gluteus Medius Muscles with the Presence of Simulated Lower Limb Dysmetria.

(1) Background: Leg length discrepancy (LLD), regardless of its origin, is a very common pathology that can contribute to low back pain. Various authors have pointed out its relationship with the lack of activation of both the gluteus medius (GM) and the ipsilateral erector spinae (ES). The purpose of this study was to identify the activation of the ES and GM with different simulated LLDs, correlating this activation with LBP. In turn, we evaluated whether ES and GM activity has an effect on jumping ability using a CMJ test. (2) Method: A sample of healthy subjects was selected to whom an artificial LLD was applied using 0.5, 1, and 1.5 cm insoles. These three heights were measured using EMG while the subjects walked and performed a counter movement jump (CMJ). The measurements of the insole heights were carried out in random order using a Latin square. Muscle activation patterns were recorded for 30 s at each of the insole heights while the patients walked at 5.7 km/h and they were compared with the maximum voluntary contraction (MVC), both on the ipsilateral and contralateral sides. These muscles were then measured under the same circumstances during the performance of the CMJ. (3) Results: We found statistically significant differences in the flight heights in both the CMJ and DJ. In the comparison, significant differences were found in the flight heights of the CMJ and the DJ using the 5 mm insoles, and in the case of the DJ, also without insoles, with respect to the MVC. We found statistically significant differences in the activation of the GM with the differences in insoles, but not in the activation of the Es in relation to the different insole heights. (4) Conclusions: Insoles of different heights caused activation differences in the medius on the side where the insoles were placed. We can relate this difference in activation to LBP. In relation to the ES, no significant differences were found in the activation of the ipsilateral side of the insole.

Brain immunity response of fish Eleginops maclovinus to infection with Francisella noatunensis.

The brain's immune system is selective and hermetic in most species, including fish, favoring immune responses mediated by soluble immunomodulatory factors such as serotonin and the availability of nutrients against infectious processes. Francisella noatunensis coexist with fish such as Eleginops maclovinus, which raises questions about the susceptibility and immune response of the brain of E. maclovinus against Francisella. In this study, we inoculated fish with different doses of Francisella and took samples for 28 days. We detected bacteria in the brain of fish injected with a high concentration of Francisella at all time points. qPCR analysis of immune genes indicated a response mainly in the medium-dose and early expression of genes involved in iron metabolism. Finally, brain serotonin levels were higher than in uninfected fish in all conditions, suggesting possible immunomodulatory participation in an infectious process.

The Relationship between the IC50 Values and the Apparent Inhibition Constant in the Study of Inhibitors of Tyrosinase Diphenolase Activity Helps Confirm the Mechanism of Inhibition.

Tyrosinase is the enzyme involved in melanization and is also responsible for the browning of fruits and vegetables. Control of its activity can be carried out using inhibitors, which is interesting in terms of quantitatively understanding the action of these regulators. In the study of the inhibition of the diphenolase activity of tyrosinase, it is intriguing to know the strength and type of inhibition. The strength is indicated by the value of the inhibition constant(s), and the type can be, in a first approximation: competitive, non-competitive, uncompetitive and mixed. In this work, it is proposed to calculate the degree of inhibition (iD), varying the concentration of inhibitor to a fixed concentration of substrate, L-dopa (D). The non-linear regression adjustment of iD with respect to the initial inhibitor concentration [I]0 allows for the calculation of the inhibitor concentration necessary to inhibit the activity by 50%, at a given substrate concentration (IC50), thus avoiding making interpolations between different values of iD. The analytical expression of the IC50, for the different types of inhibition, are related to the apparent inhibition constant (KIapp). Therefore, this parameter can be used: (a) To classify a series of inhibitors of an enzyme by their power. Determining these values at a fixed substrate concentration, the lower IC50, the more potent the inhibitor. (b) Checking an inhibitor for which the type and the inhibition constant have been determined (using the usual methods), must confirm the IC50 value according to the corresponding analytical expression. (c) The type and strength of an inhibitor can be analysed from the study of the variation in iD and IC50 with substrate concentration. The dependence of IC50 on the substrate concentration allows us to distinguish between non-competitive inhibition (iD does not depend on [D]0) and the rest. In the case of competitive inhibition, this dependence of iD on [D]0 leads to an ambiguity between competitive inhibition and type 1 mixed inhibition. This is solved by adjusting the data to the possible equations; in the case of a competitive inhibitor, the calculation of KI1app is carried out from the IC50 expression. The same occurs with uncompetitive inhibition and type 2 mixed inhibition. The representation of iD vs. n, with n=[D]0/KmD, allows us to distinguish between them. A hyperbolic iD vs. n representation that passes through the origin of coordinates is a characteristic of uncompetitive inhibition; the calculation of KI2app is immediate from the IC50 value. In the case of mixed inhibitors, the values of the apparent inhibition constant of meta-tyrosinase (Em) and oxy-tyrosinase (Eox), KI1app and the apparent inhibition constant of metatyrosinase/Dopa complexes (EmD) and oxytyrosinase/Dopa (EoxD), KI2app are obtained from the dependence of iD vs. n, and the results obtained must comply with the IC50 value.

Oxygen Uptake Slow Component and the Efficiency of Resistance Exercises.

ABSTRACT: Garnacho-Castaño, MV, Albesa-Albiol, L, Serra-Payá, N, Gomis Bataller, M, Pleguezuelos Cobo, E, Guirao Cano, L, Guodemar-Pérez, J, Carbonell, T, Domínguez, R, and Maté-Muñoz, JL. Oxygen uptake slow component and the efficiency of resistance exercises. J Strength Cond Res 35(4): 1014-1022, 2021-This study aimed to evaluate oxygen uptake slow component (V̇o2sc) and mechanical economy/efficiency in half squat (HS) exercise during constant-load tests conducted at lactate threshold (LT) intensity. Nineteen healthy young men completed 3 HS exercise tests separated by 48-hour rest periods: 1 repetition maximum (1RM), incremental-load HS test to establish the %1RM corresponding to the LT, and constant-load HS test at the LT. During the last test, cardiorespiratory, lactate, and mechanical responses were monitored. Fatigue in the lower limbs was assessed before and after the constant-load test using a countermovement jump test. A slight and sustained increase of the V̇o2sc and energy expended (EE) was observed (p < 0.001). In blood lactate, no differences were observed between set 3 to set 21 (p > 0.05). A slight and sustained decrease of half squat efficiency and gross mechanical efficiency (GME) was detected (p < 0.001). Significant inverse correlations were observed between V̇o2 and GME (r = -0.93, p < 0.001). Inverse correlations were detected between EE and GME (r = -0.94, p < 0.001). Significant losses were observed in jump height ability and in mean power output (p < 0.001) in response to the constant-load HS test. In conclusion, V̇o2sc and EE tended to rise slowly during constant-load HS exercise testing. This slight increase was associated with lowered efficiency throughout constant-load test and a decrease in jump capacity after testing. These findings would allow to elucidate the underlying fatigue mechanisms produced by resistance exercises in a constant-load test at LT intensity.

Procalcitonin and C-reactive protein as early markers of anastomotic leak after laparoscopic colorectal surgery within an enhanced recovery after surgery (ERAS) program.

BACKGROUND: C-reactive protein (CRP) and procalcitonin (PCT) have been described as good predictors of anastomotic leak after colorectal surgery, obtaining the highest diagnostic accuracy on the 5th postoperative day. However, if an enhanced recovery after surgery (ERAS) program is performed, early predictors are needed in order to ensure a safe and early discharge. The aim of this study was to investigate the efficacy of CRP, PCT, and white blood cell (WBC) count determined on first postoperative days, in predicting septic complications, especially anastomotic leak, after laparoscopic colorectal surgery performed within an ERAS program. METHODS: We conducted a prospective study including 134 patients who underwent laparoscopic colorectal surgery within an ERAS program between 2015 and 2017. The primary endpoint investigated was anastomotic leak. CRP, PCT, and WBC count were determined in the blood sample extracted on postoperative day 1 (POD 1), POD 2 and POD 3. RESULTS: Anastomotic leak (AL) was detected in 6 patients (4.5%). Serum levels of CRP and PCT, but not WBC, determined on POD 1, POD 2, and POD 3 were significantly higher in patients who had AL in the postoperative course. Using ROC analysis, the best AUC of the CRP and PCT levels was on POD 3 (0.837 and 0.947, respectively). A CRP cutoff level at 163 mg/l yielded 85% sensitivity, 80% specificity, and 99% negative predictive value (NPV). A PCT cutoff level at 2.5 ng/ml achieved 85% sensitivity, 95% specificity, 44% positive predictive value, and 99% NPV. CONCLUSIONS: CRP and PCT are relevant markers for detecting postoperative AL after laparoscopic colorectal surgery. Furthermore, they can ensure an early discharge with a low probability of AL when an ERAS program is performed.

Lactate Threshold as a Measure of Aerobic Metabolism in Resistance Exercise.

In resistance training, load intensity is usually calculated as the percentage of a maximum repetition (1RM) or maximum number of possible repetitions (% of 1RM). Some studies have proposed a lactate threshold (LT) intensity as an optimal approach for concurrent training of cardiorespiratory endurance and muscle strength, as well as an alternative in resistance training. The objective of the present study was to analyze the results obtained in research evaluating the use of LT in resistance training. A keyword and search tree strategy identified 14 relevant articles in the Dialnet, Elsevier, Medline, Pubmed, Scopus and Web of Science databases. Based on the studies analyzed, the conclusion was that the LT in resistance exercises can be determined either by mathematical methods or by visual inspection of graphical plots. Another possibility is to measure the intensity at which LT might coincide with the first ventilatory threshold (VT1). Since performing an exercise session at one's LT intensity has been shown to accelerate the cardiorespiratory response and induce neuromuscular fatigue, this intensity could be used to set the training load in a resistance training program.

Exercise Prescription Using the Borg Rating of Perceived Exertion to Improve Fitness.

The present study aimed to compare two fitness-training methodologies, instability circuit resistance training (ICRT) versus traditional circuit resistance training (TCRT), applying an experimental model of exercise prescription controlling and modulating exercise load using the Borg rating of perceived exertion. Forty-four healthy young adults age (21.6±2.3 years) were randomly assigned to three groups: TCRT (n=14), ICRT (n=14) and a control group (n=16). Strength and cardiorespiratory tests were chosen to evaluate cardiorespiratory and muscular fitness before and after the training program. In cardiorespiratory data, a significant difference was observed for the time effect in VO2max, peak heart rate, peak velocity, and heart rate at anaerobic threshold intensity (p<0.05) in the experimental groups. In strength variables, a significant Group x Time interaction effect was detected in 1RM, in mean propulsive power, and in peak power (p≤0.01) in the back squat exercise. In the bench press exercise, a significant time effect was detected in 1RM, in mean propulsive power, and in peak power, and a Group x Time interaction in peak power (all p<0.05). We can conclude that applying an experimental model of exercise prescription using RPE improved cardiorespiratory and muscular fitness in healthy young adults in both experimental groups.

Implementation of the Spanish ERAS program in bariatric surgery.

Introduction: The essence of Enhanced Recovery After Surgery (ERAS) programs is the multimodal approach, and many authors have demonstrated safety and feasibility in fast track bariatric surgery. According to this concept, a multidisciplinary ERAS program for bariatric surgery has been developed by the Spanish Fast Track Group (ERAS Spain). The aim of this study was to analyze the initial implementation of this Spanish National ERAS protocol in bariatric surgery, comparing it with a historical cohort receiving standard care. Material and methods: A multi-centric prospective study was performed, including 233 consecutive patients undergoing bariatric surgery during 2015 and following ERAS protocol. It was compared with a historical cohort of 286 patients, who underwent bariatric surgery at the same institutions between 2013 and 2014 and following standard care. Compliance with the protocol, morbidity, mortality, hospital stay and readmission were evaluated. Results: Bariatric techniques performed were Roux-en-Y gastric bypass and sleeve gastrectomy. There were no significant differences in complications, mortality and readmission. Postoperative pain and hospital stay were significantly lower in the ERAS group. The total compliance to protocol was 80%. Conclusion: The Spanish National ERAS protocol is a safe issue, obtaining similar results to standard care in terms of complications, reoperations, mortality and readmissions. It is associated with less postoperative pain and earlier hospital discharge.

C-reactive protein, fibrinogen, and procalcitonin levels as early markers of staple line leak after laparoscopic sleeve gastrectomy in morbidly obese patients within an Enhanced Recovery After Surgery (ERAS) program.

INTRODUCTION: The performance of most bariatric procedures within an Enhanced Recovery After Surgery program has resulted in significant advantages, including a reduction in the length of hospital stay to 2-3 days. However, some postoperative complications may appear after the patient has been discharged. The aim of this study was to investigate the efficacy of various acute-phase parameters determined 24 h after a laparoscopic sleeve gastrectomy for predicting staple line leak in the postoperative course. PATIENTS AND METHODS: A prospective study of 208 morbidly obese patients undergoing laparoscopic sleeve gastrectomy as bariatric procedure between 2012 and 2015 was performed. Blood analysis was performed 24 h after surgery. Acute-phase parameters (C-reactive protein, procalcitonin, fibrinogen, and White Blood Cell count) were investigated. RESULTS: Staple line leak appeared in eight patients (3.8%). Using receiver operating characteristic analysis at 24 h postoperatively, a cutoff level of CRP at 9 mg/dL achieved 85% sensitivity and 90% specificity for predicting staple line leak, a cutoff level of procalcitonin at 0.85 ng/mL achieved 70% sensitivity and 90% specificity, and a cutoff level of fibrinogen at 600 mg/dL achieved 80% sensitivity and 87.5% specificity. CONCLUSION: An elevation of CRP > 9 mg/dL, procalcitonin > 0.85 ng/mL and fibrinogen > 600 mg/dL should alert the surgeon the possibility of occurrence of postoperative staple line leak.

Postoperative pain after laparoscopic sleeve gastrectomy: comparison of three analgesic schemes (isolated intravenous analgesia, epidural analgesia associated with intravenous analgesia and port-sites infiltration with bupivacaine associated with intravenous analgesia).

INTRODUCTION: Although bariatric surgery is actually mainly performed laparoscopically, analgesic optimization continues being essential to reduce complications and to improve the patients' comfort. The aim of this study is to evaluate the postoperative pain after analgesia iv exclusively, or associated with epidural analgesia or port-sites infiltration with bupivacaine. PATIENTS AND METHODS: A prospective randomized study of patients undergoing laparoscopic sleeve gastrectomy between 2012 and 2014 was performed. Patients were divided into three groups: Analgesia iv exclusively (Group 1), epidural analgesia + analgesia iv (Group 2) and port-sites infiltration + analgesia iv (Group 3). Pain was quantified by means of a Visual Analogic Scale, and morphine rescue needs were determined 24 h after surgery. RESULTS: A total of 147 were included. Groups were comparable in age, gender and BMI. There were no differences in operation time, complications, mortality or hospital stay between groups. Median pain 24 h after surgery was 5 in Group 1, 2.5 in Group 2 and 2 in Group 3 (P = 0.01), without statistically significant differences between Groups 2 and 3. In Group 1, morphine rescue was necessary in 16.3 % of the cases, 2 % in Group 2 and 2 % in Group 3 (P = 0.014), without statistically significant differences between Groups 2 and 3. CONCLUSION: Epidural analgesia and port-sites infiltration with bupivacaine, associated with analgesia iv, reduce the postoperative pain, when compared with analgesia iv exclusively. CLINICAL TRIALS: ClinicalTrials.gov Identifier: NCT02662660.

Failure of fragmented parathyroid gland autotransplantation to prevent permanent hypoparathyroidism after total thyroidectomy.

PURPOSE: Parathyroid autotransplantation during total thyroidectomy leads to higher rates of postoperative hypocalcaemia. It has been argued, however, that it prevents permanent hypoparathyroidism. The impact of autografted normal parathyroid gland fragments on long-term parathyroid status has not been assessed properly. To clarify this, the short- and long-term parathyroid function was assessed in patients with three glands remaining in situ after total thyroidectomy, in whom the fourth gland was either autotransplanted (Tx) or accidentally resected (AR). METHODS: Consecutive patients (n = 669) undergoing first-time total thyroidectomy were prospectively studied recording the number of parathyroid glands remaining in situ: PGRIS =4-(glands autografted + glands in the specimen). The study was focused on the subgroup of 186 patients with three parathyroid glands remaining in situ as a result of either accidental resection (AR, n = 76) or autotransplantation into the sternocleidomastoid muscle (Tx, n = 110). Prevalence of postoperative hypocalcaemia, protracted, and permanent hypoparathyroidism were compared between the two groups. Demographic, disease-related, laboratory, and surgical variables were recorded. All patients were followed for at least 1 year. RESULTS: Both groups were comparable in terms of disease and extent of surgery. Mean postoperative serum calcium was the same (AR: 1.97 ± 0.2 vs Tx: 1.97 ± 0.22 mmol/L). Rates of protracted (AR: 24% vs Tx: 25.5%) and permanent hypoparathyroidism (AR: 5.3% vs Tx: 7.3%) were similar in both groups. CONCLUSIONS: The prevalence of parathyroid failure syndromes after total thyroidectomy was similar whether a parathyroid gland was inadvertently excised or autotransplanted. Autotransplantation did not influence the permanent hypoparathyroidism rate.

Conservative management in ureteric hydronephrosis due to deep endometriosis: Could the levonorgestrel-intrauterine device be an option?

Endometriosis can affect up to 10% of women of reproductive age, in a wide range of clinical presentations that vary from mild to severe or deep endometriosis. Deep endometriosis can affect the urinary tract in 1-5% to 15-25% cases. Even though deep endometriosis' surgeries are usually complex with higher rate of complications, conservative management is not always considered as an option because of its high failure rates. This paper describes two cases of deep endometriosis with ureteric involvement (hydronephrosis) treated conservatively with a double-pigtail stent plus a Levonorgestrel intrauterine device, after conservative surgery, who remained symptom free with no evidence of recurrence at 3 years follow-up, avoiding radical high-risk surgery. Impact statement Several treatments have been described for endometriosis. From a symptomatic perspective, conservative medical management has been proposed with a variable response. Concerning deep endometriosis (affecting the urinary or digestive tract), the definitive treatment has always been thought to be radical surgery. However, this can lead to several complications. To illustrate a possible more conservative approach this paper describes two cases of deep infiltrating endometriosis affecting the ureter, treated conservatively with a temporary pigtail ureter stent plus a Levonorgestrel intrauterine device. The management demonstrates that, in a selected population, conservative treatment solves the urinary disease avoiding the surgical complications and, what is more, improving patients' symptoms in a permanent way. Further prospective studies are needed to confirm whether the introduction of this management in clinical practice would reduce the need for surgery thereby, avoiding high-risk surgery and improving the success rate of conservative management.

Perioperative immunonutrition in normo-nourished patients undergoing laparoscopic colorectal resection.

OBJECTIVE: To determine whether the joint implementation of immunonutrition and a laparoscopic approach improves morbidity, mortality, and length of stay (LOS) compared with dietary advice. BACKGROUND: Despite progress in recent years in the surgical management of patients with colorectal cancer, postoperative complications are frequent. Nutritional supplements enriched with immunonutrients have recently been introduced into clinical practice. However, the immunonutrition benefits in patients undergoing colorectal laparoscopic surgery are unknown. METHODS: This study was a prospective, randomized trial with two parallel treatment groups receiving an immune-enhancing dietary supplement for 7 days before colorectal resection and 5 days postoperatively or dietary advice. RESULTS: A total of 128 patients were randomized. At baseline, both groups were comparable with respect to age, sex, surgical risk, comorbidities, and analytical and nutritional parameters. The median postoperative LOS was 5 days and was not significantly different between the groups. Wound infection differed significantly between the groups (11.50 vs. 0.00 %, p = 0.006). No other differences between the groups were identified. CONCLUSIONS: The joint use of laparoscopy and supplementation with immunonutrients reduces surgical wound infection in patients undergoing colorectal surgery. TRIAL REGISTRATION: This study is registered with ClinicalTrial.gov : NCT0239396.

Patient-derived olfactory mucosa for study of the non-neuronal contribution to amyotrophic lateral sclerosis pathology.

Amyotrophic lateral sclerosis (ALS) is a degenerative motor neuron disease which currently has no cure. Research using rodent ALS models transgenic for mutant superoxide dismutase 1 (SOD1) has implicated that glial-neuronal interactions play a major role in the destruction of motor neurons, but the generality of this mechanism is not clear as SOD1 mutations only account for less than 2% of all ALS cases. Recently, this hypothesis was backed up by observation of similar effects using astrocytes derived from post-mortem spinal cord tissue of ALS patients which did not carry SOD1 mutations. However, such necropsy samples may not be easy to obtain and may not always yield viable cell cultures. Here, we have analysed olfactory mucosa (OM) cells, which can be easily isolated from living ALS patients. Disease-specific changes observed when ALS OM cells were co-cultured with human spinal cord neurons included decreased neuronal viability, aberrant neuronal morphology and altered glial inflammatory responses. Our results show the potential of OM cells as new cell models for ALS.

Cardiorespiratory and Metabolic Responses to Loaded Half Squat Exercise Executed at an Intensity Corresponding to the Lactate Threshold.

This study was designed to identify the blood lactate threshold (LT2) for the half squat (HS) and to examine cardiorespiratory and metabolic variables during a HS test performed at a work intensity corresponding to the LT2. Twenty-four healthy men completed 3 test sessions. In the first, their one-repetition maximum (1RM) was determined for the HS. In the second session, a resistance HS incremental-load test was performed to determine LT2. Finally, in the third session, subjects performed a constant-load HS exercise at the load corresponding to the LT2 (21 sets of 15 repetitions with 1 min of rest between sets). In this last test, blood samples were collected for lactate determination before the test and 30 s after the end of set (S) 3, S6, S9, S12, S15, S18 and S21. During the test, heart rate (HR) was telemetrically monitored and oxygen consumption (VO2), carbon dioxide production (VCO2), minute ventilation (VE), respiratory exchange ratio (RER), ventilatory equivalent for O2 (VE·VO2 (-1)) and ventilatory equivalent for CO2 (VE·VCO2 (-1)) were monitored using a breath-by-breath respiratory gas analyzer. The mean LT2 for the participants was 24.8 ± 4.8% 1RM. Blood lactate concentrations showed no significant differences between sets 3 and 21 of exercise (p = 1.000). HR failed to vary between S6 and S21 (p > 1.000). The respiratory variables VO2, VCO2, and VE·VCO2 (-1) stabilized from S3 to the end of the constant-load HS test (p = 0.471, p = 0.136, p = 1.000), while VE and VE·VO2 (-1) stabilized from S6 to S21. RER did not vary significantly across exercise sets (p = 0.103). The LT2 was readily identified in the incremental HS test. Cardiorespiratory and metabolic variables remained stable during this resistance exercise conducted at an exercise intensity corresponding to the LT2. These responses need to be confirmed for other resistance exercises and adaptations in these responses after a training program also need to be addressed. Key pointsIt can be identified lactate threshold at half-squat.Exercise intensity is predominantly aerobic.The duration of the half-squat can be maintained over time, ~30 min of discontinuous exercise (21 sets, 15 repetitions, 1 min rest).Lactate threshold intensity may be suitable for older adults, sedentary individuals, patients or subjects with a lower functional capacity and even for resistance sports athletes.

Catalysis and inactivation of tyrosinase in its action on hydroxyhydroquinone.

Hydroxyhydroquinone (HHQ) was characterized kinetically as a tyrosinase substrate. A kinetic mechanism is proposed, in which HHQ is considered as a monophenol or as an o-diphenol, depending on the part of the molecule that interacts with the enzyme. The kinetic parameters obtained from an analysis of the measurements of the initial steady state rate of 2-hydroxy p-benzoquinone formation were kcatapp=229.0±7.7 s(-1) and KMapp,HHQ=0.40±0.05 mM. Furthermore, the action of tyrosinase on HHQ led to the enzyme's inactivation through a suicide inactivation mechanism. This suicide inactivation process was characterized kinetically by λmaxapp (the apparent maximum inactivation constant) and r, the number of turnovers made by 1 mol of enzyme before being inactivated. The values of λmaxapp and r were (8.2±0.1)×10(-3) s(-1) and 35,740±2,548, respectively.

Structural properties and singular phase transitions of metallic Pr0.50Sr0.50CoO3 cobaltite.

The Pr0.50Sr0.50CoO3 perovskite exhibits unique magnetostructural properties among the rest of the ferromagnetic/metallic Ln0.50Sr0.50CoO3 compounds. Existing reports are largely controversial. We have determined and described its structural evolution, which follows the Pm3̅m → R3̅c → Imma → I4/mcm transformations. The structural changes have been thoroughly described. The results are confronted with distinct nonconventional properties and spin-lattice coupling effects in another half-doped cobaltite based on praseodymium, Pr0.50Ca0.50CoO3. The Imma → I4/mcm symmetry change is responsible for the unexpected second magnetic transition.

Stability of the cationic oxidation states in Pr(0.50)Sr(0.50)CoO3 across the magnetostructural transition by X-ray absorption spectroscopy.

The possible hybridization between Pr 4f and O 2p states in Pr(0.50)Sr(0.50)CoO3 at low temperatures was investigated by different techniques. First, using neutron diffraction we observed a strong contraction of some Pr-O bonds across the magnetostructural transition at T(S) ∼ 120 K. In contrast to the Pr-O bond contraction in Pr(0.50)Sr(0.50)CoO3, this transition is not accompanied by the appearance of Pr(4+) at low temperatures, as revealed by X-ray absorption spectroscopy at Pr edges. Despite the fact that a Pr valence change is not the mechanism that drives this transition, we point out an active participation of Pr ions across T(S). Moreover, Co L(2,3)-edge and O K edge X-ray absorption spectra did not reveal any spin-state variation and showed the stability of the average formal valence of cobalt ions. The large density of empty t(2g) symmetry states in the studied thermal range does not suggest the occurrence of Co(3+) in a pure low-spin state. The overall metallic behavior agrees with our findings. We propose a mixture of Co(3+) ions in the intermediate-spin or high-spin configuration together with Co(4+) ions in a low- or intermediate-spin state.