30-min Protocol Research Articles

Evaluating color change and hydrogen peroxide penetration in human and bovine teeth through in-office bleaching procedures.

Assess color alteration and hydrogen peroxide (HP) penetration in human and bovine teeth using various in-office bleaching protocols with different application times. Thirty healthy human premolars and 30 healthy bovine incisors were divided into five groups and subjected to different bleaching protocols: 2 × 15 min, 1 × 30 min, 2 × 20 min, or 1 × 40 min, with a control group for each tooth type. All teeth were treated with 35% HP gel. Color alteration was measured using digital spectrophotometry before and 1 week after bleaching. HP concentration within the pulp was determined via UV-Vis spectrophotometry. Statistical analysis included one-way ANOVA, Tukey's, and Dunnett's tests (α = 0.05). All groups exhibited significant color alteration, with no statistically differences among them (p > 0.05). However, significant differences were observed when compared with their respective control groups (p < 0.05). HP penetration into the pulp was evident in all bleached teeth compared to the control groups (p < 0.05), with the 2 × 20 group showing the highest HP levels within the pulp cavity, irrespective of tooth type (p < 0.05). A simplified 1 × 30-min protocol can be recommended as it effectively maintains color alteration and HP penetration, irrespective of whether human or bovine teeth. This study suggests that an in-office dental bleaching protocol using a 1 × 30-min session is recommended, as it ensures both effective color change and no increase in the amount of HP penetration.

Clinical implications of imprecise sampling time for 10- and 30-min thyrotropin-releasing hormone stimulation tests in horses.

The thyrotropin-releasing hormone (TRH) stimulation test is used to diagnose pituitary pars intermedia dysfunction (PPID) using 10- or 30-min protocols. Imprecise sampling time for the 10-min protocol can lead to misdiagnoses. To determine the effect of imprecise sampling time for the 30-min protocol of the TRH stimulation test. In vivo experiment. Plasma immunoreactive adrenocorticotropin (ACTH) concentrations were measured 9, 10, 11, 29, 30 and 31 min after intravenous administration of 1 mg of TRH in 15 control and 12 PPID horses. Differences in ACTH concentrations between sampling times, variability in ACTH concentrations between protocols, and diagnostic classification of PPID were assessed using Friedman's test, Bland-Altman plots, and Fisher's exact test, respectively, with 95% confidence intervals reported and significance set at p < 0.05. Imprecise sampling time resulted in variable ACTH concentrations, but significant differences in absolute ACTH concentrations were not detected for imprecise sampling within each protocol or between protocols. Imprecise sampling changed PPID diagnostic classification for 3/27 (11 [4-28] %) horses for both protocols. Using the 30-min protocol as a reference, 1/12 (8 [1-35] %) horses returned a negative test result and 5/12 (42 [19-68] %) horses returned equivocal test results that would be considered positive in practice due to the presence of supportive clinical signs. Limited sample size and inter-horse variability reduced the ability to detect small but potentially relevant differences. Overall, the impact of imprecise sampling was not significantly different between the 10- and 30-min TRH stimulation test protocols. However, diagnostic classification for PPID would have varied between the 10- and 30-min protocols in this population, if clinical signs had been ignored. Precise timing during TRH stimulation tests and contextual interpretation of ACTH concentrations remain fundamental for the diagnosis of PPID.

Influence of exercise duration on respiratory function and systemic immunity among healthy, endurance-trained participants exercising in sub-zero conditions

BackgroundStrenuous endurance exercise in sub-zero temperatures can cause airway damage that may lead to EIB. Prolonged exercise can also elicit greater immune perturbations than short-duration exercise. However, the influence of exercise duration on lung function and systemic immunity in sub-zero temperatures has not been established. Additionally, it is currently unknown whether atopic disposition, which is risk factor for EIB, influences respiratory responses in a sub-zero climate. The aim of this study was to compare respiratory and systemic immune responses to two cold air running trials of short and long duration, as well as to examine whether the responses differed between atopic and non-atopic subjects.MethodsEighteen healthy, endurance-trained subjects (males/females: 14/4; age: 29.4 ± 5.9 years old; BMI: 23.1 ± 1.7; atopic/non-atopic: 10/8) completed two moderate-intensity climate chamber running trials at − 15 °C, lasting 30 and 90 min, in a randomized, cross-over design. Lung function (spirometry and impulse oscillometry), serum CC16, respiratory symptoms, and blood leukocyte counts were examined before and after the trials.ResultsLung function was not significantly affected by exercise or exercise duration. CC16 concentration increased after both trials (p = 0.027), but the response did not differ between trials. Respiratory symptom intensity was similar after each trial. There was a greater increase in neutrophils (p < 0.001), and a decrease in eosinophils (p < 0.001) after the 90-min bout. The 90-min protocol increased X5 compared to the 30-min protocol only in atopic subjects (p = 0.015) while atopy increased lower airway symptoms immediately after the 90-min session (p = 0.004).ConclusionsOur results suggest that a 90-min bout of moderate-intensity exercise at − 15 °C does not cause substantial lung function decrements, airway epithelial damage or respiratory symptoms compared to 30 min running in the same environment, despite a heightened redistribution of white blood cells. However, exercise at − 15 °C may cause airway injury and evoke respiratory symptoms, even at moderate intensity. Atopic status may lead to greater peripheral bronchodilation and higher frequency of respiratory symptoms after long-duration exercise in cold.Trial registration: 01/02/2022 ISRCTN13977758. This trial was retrospectively registered upon submission to satisfy journal guidelines. The authors had not initially registered the study, as the intervention was considered to be a controlled simulation of exercise in a naturally occurring environment (i.e. sub-zero air) for healthy volunteers.

Dynamic planar scintigraphy for the rapid kinetic measurement of myocardial 123I-MIBG turnover can identify Lewy body disease

BackgroundUsing two static scans for 123I-meta-iodobenzyl-guanidine (123I-MIBG) myocardial scintigraphy ignores the dynamic response from vesicular trapping in nerve terminals. Moreover, the long pause between scans is impractical for patients with Lewy body diseases (LBDs). Here, we optimized indices that capture norepinephrine kinetics, tested their diagnostic performance, and determined the differences in 123I-MIBG performance among disease groups.MethodsWe developed a new 30-min protocol for 123I-MIBG dynamic planar imaging for suspected LBD patients. Pharmacokinetic modelling of time-activity curves (TACs) was used to calculate three new indices: unidirectional uptake of 123I-MIBG to vesicular trapping (iUp), rate of myocardial 123I-MIBG loss (iLoss), and non-specific fractional distribution of 123I-MIBG in the interstitial space. We compared the performance of the new and existing indices with regard to discrimination of patients with or without LBDs. Subgroup analysis was performed to examine differences in 123I-MIBG turnover between patients in a dementia with Lewy bodies (DLB) group and two Parkinson’s disease (PD) groups, one with and the other without REM sleep behaviour disorder (RBD).ResultsiLoss was highly discriminative, particularly for patients with low myocardial 123I-MIBG trapping, and the new indices outperformed existing ones. ROC analysis revealed that the AUC of iLoss (0.903) was significantly higher than that of early HMR (0.863), while comparable to that of delayed HMR (0.892). The RBD-positive PD group and the DLB group had higher turnover rates than the RBD-negative PD group, indicating a potential association between prognosis and iLoss.Conclusion123I-MIBG turnover can be quantified in 30 min using a three-parameter model based on 123I-MIBG TACs. The discriminatory performance of the new model-based indices might help explain the neurotoxicity or neurodegeneration that occurs in LBD patients.

Realidad virtual de bajo coste. Una nueva aplicación para rehabilitación motora de los miembros superiores en patología neurológica: Estudio piloto

Background and objectivesThe aim of this study is to present a new virtual reality (VR) low cost application based on Leap Motion Controller (LMC) device for upper extremity motor rehabilitation after neurological pathology and to demonstrate its clinical feasibility by carrying out a pilot experience. Material and methodsThe LMC allows the interaction with virtual applications by capturing the patient's hand movements. A pilot study was carried out with 4 patients with upper limb impairment reflected with Upper Extremity Motor Score (UEMS) greater than 10. They were assessed using the Box and Block (BBT) and the writing task within the Jebsen-Taylor Hand Function (JTHF) before and after the intervention. ResultsAll patients completed the 9-session, 30-min protocol divided into 3 sessions per week. They went from an average result of 38 (SD 20) blocks in BBT before the intervention to 44 (SD 21.72) after it. They went from 28.25 s (SD 8.61) to 26.75 s (SD 21.72) in the JTHF. Statistically significant differences were no found. The device usability was assessed by the QUEST scale, being the security, effectiveness and ease to use the aspects that patients considered to be a priority. ConclusiónA new VR development based on the LMC device is presented and the clinical feasibility of its application in neurological patients with upper limb involvement has been proven. A clinical study with a large sample size is needed to assess its potential clinical effectiveness as a treatment element.

The effect of downhill running conditions on muscle damage in recreationally active adults

Background: Downhill running (DR) has been used extensively to investigate recovery from muscle-damaging exercise. There is no consensus on the optimal conditions (duration, severity, intensity) for a DR protocol. The purpose of this research was to determine the most effective DR conditions to induce muscle damage. Methods: The research was comprised a 3x3 within-between participant design. Recreationally active males’ (n = 12) muscle damage was assessed using gold standard indirect markers (force loss and muscle soreness) at baseline, 24 and 48h post one of three DR conditions (a. 45min at -10% gradient b. 45min at -12% c. 30min at -15%). DR was completed on a motorised treadmill at 70% velocity of VO 2 peak achieved during an incremental exercise test to exhaustion. Results: Isometric force (p = .005, η p 2 = 0.45) and muscle soreness (p = .002, η p 2 = 0.49) were impaired 24h post-exercise; no difference (p > .05) was evident between conditions. At 48h the impairments in force loss and muscle soreness were no longer evident (p > .05) across all conditions. There was no difference (p = .82) in HR between the DR conditions. Findings: Independent of duration and gradient all conditions resulted in a similar response in force loss and muscle soreness, indicating muscle damage had occurred. Interestingly, the 30-min protocol produced the same response in less time, without requiring individuals to work at a greater intensity. Therefore, the 30-min condition is suggested as the most appropriate protocol for use in the scientific investigation of muscle damage from DR.

Symptom response analysis of a randomized controlled trial of reflexology for symptom management among women with advanced breast cancer

To examine symptom responses resulting from a home-based reflexology intervention delivered by a friend/family caregivers to women with advanced breast cancer undergoing chemotherapy, targeted, and/or hormonal therapy. Patient-caregiver dyads (N = 256) were randomized to 4 weekly reflexology sessions or attention control. Caregivers in the intervention group were trained by a reflexology practitioner in a 30-min protocol. During the 4weeks, both groups completed telephone symptom assessments using the M. D. Anderson Symptom Inventory. Those who completed at least one weekly call were included in this secondary analysis (N = 209). Each symptom was categorized as mild, moderate, or severe using established interference-based cut-points. Symptom response meant an improvement by at least one category or remaining mild. Symptom responses were treated as multiple events within patients and analyzed using generalized estimating equations technique. Reflexology was more successful than attention control in producing responses for pain (OR = 1.84, 95% CI (1.05, 3.23), p = 0.03), with no significant differences for other symptoms. In the reflexology group, greater probability of response across all symptoms was associated with lower number of comorbid condition and lower depressive symptomatology at baseline. Compared to odds of responses on pain (chosen as a referent symptom), greater odds of symptom response were found for disturbed sleep and difficulty remembering with older aged participants. Home-based caregiver-delivered reflexology was helpful in decreasing patient-reported pain. Age, comorbid conditions, and depression are potentially important tailoring factors for future research and can be used to identify patients who may benefit from reflexology. ClinicalTrials.gov Identifier: NCT01582971.

True exposure to lead at the tap: Insights from proportional sampling, regulated sampling and water use monitoring

This work aimed to evaluate the ability of four regulatory sampling protocols to accurately determine weekly water lead levels (WLLs) of exposure at the kitchen tap in twenty-nine households with or without a lead service line (LSL). Proportional sampling was used as the gold standard to which the other protocols, 5-min flush, 30-min stagnation, 6-h stagnation and random daytime were compared. Random daytime samples provided mean WLLs closest to true exposure in the households monitored overall compared to other sampling protocols. Strikingly, mean WLLs after 5 min of flushing underestimated lead exposure by 47%. Supporting these observations, water usage patterns revealed that full flushing only occurs in 3.4% of usage events within the service line and in 0.26% at the tap. The time between usage events in the service line was approximately 30 min but the 30-min protocol tended to slightly underestimate WLLs. These differences were explained by flushing prior to the 30-min stagnation sampling, which limited the contribution of the LSL to WLLs. Furthermore, the average stagnation at the kitchen time was 106 min and usage events rarely exceeded the water volume within premise plumbing (1.1 L). Mean WLLs after 6 h of stagnation without flushing overestimated exposure by 29% but provided a conservative indicator of WLLs of exposure.

Critical velocity during judo-specific throwing exercise (nage-komi)

The goal of the present study was to verify if it was possible to determine the critical velocity during a judo-specific exercise and if this intensity was equivalent to stabilization in blood lactate concentration in a 30-min continuous exercise in cadet and junior judo athletes. Nine judo athletes (six males and three females) were evaluated in four sessions. During the first three sessions judo athletes performed nage-komi (technique execution throwing the partner) protocols using fixed intensities up to the exhaustion (around 1–2 min, 4–6 min and 9–10 min) to determine individual critical velocities, whereas in the fourth session judo athletes performed the nage-komi at the critical velocity and blood lactate measurements were conducted at rest, 5-min, 10-min, 20-min and 30-min to verify if a stabilization in this parameter would occur (the 30th value was compared to the 10th min value and if a difference lower than 1 mmol L− 1 was found it was considered stable). Six of the nine judo athletes were able to finish the 30-min at the critical velocity (0.21 ± 0.02 techniques/s) and three presented exhaustion in 16 min 47 s ± 7 min 21 s. For those completing the 30-min protocol, four judo athletes presented blood lactate stabilization and two presented increases over 1 mmol L-1 between the 10th and the 30th min. The critical velocity can be used as a submaximal index of aerobic fitness, although it is not correspondent to maximal lactate steady-state for a great proportion of the judo athletes investigated.

Detergent-free Ultrafast Reconstitution of Membrane Proteins into Lipid Bilayers Using Fusogenic Complementary-charged Proteoliposomes.

Detergents are indispensable for delivery of membrane proteins into 30-100 nm small unilamellar vesicles, while more complex, larger model lipid bilayers are less compatible with detergents. Here we describe a strategy for bypassing this fundamental limitation using fusogenic oppositely charged liposomes bearing a membrane protein of interest. Fusion between such vesicles occurs within 5 min in a low ionic strength buffer. Positively charged fusogenic liposomes can be used as simple shuttle vectors for detergent-free delivery of membrane proteins into biomimetic target lipid bilayers, which are negatively charged. We also show how to reconstitute membrane proteins into fusogenic proteoliposomes with a fast 30-min protocol. Combining these two approaches, we demonstrate a fast assembly of an electron transport chain consisting of two membrane proteins from E. coli, a primary proton pump bo3-oxidase and F1Fo ATP synthase, in membranes of vesicles of various sizes, ranging from 0.1 to >10 microns, as well as ATP production by this chain.

Detergent-free Ultrafast Reconstitution of Membrane Proteins into Lipid Bilayers Using Fusogenic Complementary-charged Proteoliposomes.

Detergents are indispensable for delivery of membrane proteins into 30-100 nm small unilamellar vesicles, while more complex, larger model lipid bilayers are less compatible with detergents.Here we describe a strategy for bypassing this fundamental limitation using fusogenic oppositely charged liposomes bearing a membrane protein of interest. Fusion between such vesicles occurs within 5 min in a low ionic strength buffer. Positively charged fusogenic liposomes can be used as simple shuttle vectors for detergent-free delivery of membrane proteins into biomimetic target lipid bilayers, which are negatively charged. We also show how to reconstitute membrane proteins into fusogenic proteoliposomes with a fast 30-min protocol.Combining these two approaches, we demonstrate a fast assembly of an electron transport chain consisting of two membrane proteins from E. coli, a primary proton pump bo3-oxidase and F1Fo ATP synthase, in membranes of vesicles of various sizes, ranging from 0.1 to >10 microns, as well as ATP production by this chain.

Volumetric magnetic resonance imaging correlates of the National Institute of Neurological Disorders and Stroke–Canadian Stroke Network vascular cognitive impairment neuropsychology protocols

Background: Vascular cognitive impairment (VCI) refers to the entire spectrum of cognitive dysfunction attributable to vascular changes in the brain. The objective of this study is to evaluate magnetic resonance imaging (MRI) correlates of performance on the National Institute of Neurological Disorders and Stroke–Canadian Stroke Network (NINDS–CSN) VCI neuropsychology protocols. Method: Fifty ischemic stroke patients and 50 normal elderly persons completed the VCI protocols and MRI. Relationships between the four cognitive domains (executive/activation, language, visuospatial, and memory) and three protocol (60-, 30-, and 5-min) summary scores with MRI measures of volumes of white matter hyperintensities (WMH) and global brain and hippocampal atrophy were assessed using linear regression. Results: All cognitive domain scores were associated with WMH volume and, with the exception of language domain, with global atrophy. Additional relationships were found between executive/activation and language domains with left hippocampal volume, visuospatial domain with right hippocampal volume, and memory domain with bilateral hippocampal volumes. All protocol summary scores showed comparable relationships with WMH and hippocampal volumes, with additional relationships found between the 60- and 30-min protocols with global brain volume. Conclusions: Performance on the NINDS–CSN VCI protocols reflects underlying volumetric brain changes implicated in cognitive dysfunctions in VCI.

Cardiovascular and respiratory responses to selected cranial osteopathic manipulations in healthy young adults

Background and PurposeOsteopathic manipulative treatment (OMT) for patient care may include cranial manipulations (CM). However, physiological responses to CM are not well defined. To study the effects of CM on the cardiovascular and respiratory systems the following measurements were used: heart rate (HR), HR‐variability, stroke volume index (SI), cardiac index (CI), and peak expiratory flow rate (PEFR).MethodSubjects were healthy 25–35‐yr old men and women. PEFR was measured twice, at the beginning and at the end of a 30‐min protocol. Baseline cardiac parameters were obtained after a 10‐min rest in a supine position using impedance cardiography. Following CM that was performed by an osteopathic physician, cardiac responses were measured immediately and at the end of a 10‐min rest in supine position. Data were recorded and analyzed using BIOPACK Systems, Inc. equipment and software.Results and ConclusionFollowing CM, decreases were seen in HR (4%), CI (5%), and PEFR (10%) without significant changes in SI. The HR‐variability test revealed a decrease in sympathetic and increase in parasympathetic activity. These data demonstrate that the selected cranial osteopathic techniques decreased PEFR and decreased cardiac index, primarily by decreasing heart rate without a significant effect on cardiac contractility.

Performance of a compact end-tidal forcing system

The purpose of the present study was to develop and validate a new compact, portable end-tidal forcing (ETF) system capable of reliably controlling end-tidal gases. The system consists of compressed gas sources (air, N(2) and CO(2)) that are connected via three solenoid valves to a humidification chamber and an inspiratory reservoir bag from which the participant breathes. This computer-controlled system compares actual end-tidal gas partial pressures with target pressures and mixes the gases on a breath-by-breath basis. This leaves no unused exhaust gas and keeps gas requirements to a minimum. Eight participants underwent two different 30-min protocols that included each possible combination of end-tidal O(2) partial pressure (PET O2) and end-tidal CO(2) partial pressure (PET O2) control at two different levels (PET O2 at 55 and 75 mmHg; and PET CO2 at 4 and 7 mmHg above resting). The ETF system maintained the mean PET CO2 at 0.13 mmHg from the target values, with a pooled S.D. across conditions of +/-0.91 mmHg and a 95% confidence interval (CI) of +/-0.63 mmHg. The mean PET CO2 was held at 0.49 mmHg from its target values, with a pooled S.D. across conditions of +/-1.31 mmHg and a 95% CI of +/-0.91 mmHg. To demonstrate suitability of this system for measuring chemosensitivity to hypoxia, hypoxic ventilatory response (HVR) tests were conducted in a subset of five participants. During a 20-min HVR test both PET CO2 and PET O2 were not significantly different from their target values. These data demonstrate the performance of a portable, compact, economical system that controls PET CO2 within 1 mmHg and PET O2 within 2 mmHg of their respective target values.

Effects of chronic ethanol treatment on monoamine levels in rat hippocampus and striatum

We studied the effects of ethanol on concentrations of noradrenaline (NE), dopamine (DA) and serotonin (5-HT) and their metabolites in rat hippocampus and striatum. Ethanol (2 or 4 g/kg, po, from a 20% aqueous solution) was administered daily to male Wistar rats (4-13 per group) for 30 days and animals were sacrificed 30 min or 48 h after the last administration. Monoamines were measured by HPLC and considered significant at P < 0.05. A 47% increase in 5-HT levels was observed in the hippocampus with 4 g/kg ethanol in the 30-min protocol. Ethanol (2 and 4 g/kg) decreased DA (2114.5 +/- 126.4 and 1785.1 +/- 234.2 ng/g wet tissue, respectively) and 3,4-dihydroxyphenylacetic acid (DOPAC, 1477.6 +/- 132.1 and 1218.8 +/- 271.7 ng/g wet tissue, respectively) levels, while the higher dose also decreased NE (159.8 +/- 13.5), 5-HT (228.0 +/- 46.8) and 5-hydroxy-3-indoleacetic acid (5-HIAA, 304.4 +/- 37.2 ng/g wet tissue), in the striatum after a 48-h withdrawal as compared to controls (DA: 3063.9 +/- 321.3; DOPAC: 2379.6 +/- 256.0; NE: 292.8 +/- 50.2; 5-HT: 412.4 +/- 36.2; 5-HIAA: 703.9 +/- 61.4 ng/g wet tissue). In the 30-min protocol, ethanol (2 or 4 g/kg) decreased striatal NE (66 and 70%) and DA (50 and 36%) levels. On the other hand, increases were seen in 5-HIAA (146 and 153%) and 5-HT (59 and 86%) levels. Ethanol (2 g/kg, po) increased the homovanillic acid (HVA)/DA ratio (129%) in the striatum in the 30-min protocol, while at the higher dose it increased the HVA/DA ratio in the 48-h protocol (61%). These results indicate alterations in monoamines, mainly in the striatum, after chronic ethanol, which are influenced by dose and by the length of time after the last drug administration.

Simultaneous assessment of myocardial glucose metabolism and contractile function by gated F-18-deoxyglucose positron emission tomography in infants after arterial switch operation for d-transposition of the great arteries

The arterial switch operation is now the treatment of choice for anatomic correction of dextro-transposition of the great arteries (d-TGA) in infancy. Early and late morbidity and mortality are related in part to impaired coronary perfusion due to stenosis, compression, kinking, or occlusion of the transferred coronary arteries. To guide further therapy in these patients, evaluation of myocardial viability in akinetic or hypokinetic regions is required. F-18-deoxyglucose positron emission tomography (FDG-PET) is well-established for the investigation of myocardial viability in adults. However, there are no reports about the impact of FDG-PET in infants. We applied ECG-triggered (7–12 gates) PET using a 30-min protocol for complete assessment of the metabolic and functional status of the myocardium in five infants with suspected or confirmed myocardial injury after the arterial switch operation. Left ventricular (LV) dysfunction was present in four infants. Coronary angiography revealed stenosis or occlusion of one or more coronary vessels in three patients. F-18-FDG (5–7 Mbq/kg) was injected after stimulation of glycolysis. Gated data acquisition was started 30 minutes after injection for a 20-min emission period, followed by a 10-min transmission. Glucose metabolism, wall motion, and wall thickening were evaluated visually and quantitatively from parametric 3-D images generated by a new software for wall delineation. In one infant with severely impaired LV function, PET demonstrated viable myocardium in hypokinetic regions except for a small non-transmural infarction in the apex, providing an objective indication for surgical revascularization. Another infant with severe stenosis of the left coronary artery showed no metabolic abnormality and was scheduled for coronary angioplasty. A third patient with kinking of the left and right coronary arteries had a large transmural defect corresponding to an apical and anterior infarction. These preliminary results suggest that myocardial viability and contractile function can be assessed simultaneously by gated FDG-PET in order to guide further therapy in infants with coronary stenosis or occlusion.

Effect of Peanut Blanching Protocols on Bed and Seed Temperatures, Seed Moisture, and Blanchability1

Abstract Medium commercial size, runner-type peanuts were heated in an air flow direction-controlled lab scale oven to simulate an industrial multizone dryer used in peanut blanching. Nine blanching protocols consisting of three heating times (30,45, and 60 min) factorially paired with three final oven set point temperatures (76.7, 87.8, and 98.9 C achieved from 32.2 C over six heating zones) were tested for effects on blanchability, moisture content, and temperature variation within individual seed and within the bed of peanuts. Temperature through the peanut bed varied as air flow (76.2 m/min) was reversed in alternating zones. Bed temperature variation during the heating process was highest in the 30-min protocols where the maximum difference between the top and bottom of the bed reached 17.6 C. Temperature variations decreased in the 45- and 60-min protocols; however, maximum differences as high as 8.1 C were consistently found. Bed temperature variation was related to air flow direction with higher temperatures in the peanuts nearest the air/heat source. Peanuts opposite the air flow direction did not reach the desired maximum temperature in the last zone of any protocol. Seed temperature variation was as much as 5 C between the seed surface and 3.14 mm into the seed. Seed moisture decreased from ca. 5.5% to a low of 2.94% in the 60 min/ 98.9 C protocol. Blanchability reached an upper limit of 71 to 75% in the 45- and 60-min protocols at 87.7 C and all of the protocols at 98.9 C. Blanchability was unrelated to magnitude of temperature variation in either seed or within the bed. Blanchability correlated positively with final oven set point temperature and negatively with final moisture content when moisture content was above 3.8%.

N-acetylcysteine inhibits muscle fatigue in humans.

N-acetylcysteine (NAC) is a nonspecific antioxidant that selectively inhibits acute fatigue of rodent skeletal muscle stimulated at low (but not high) tetanic frequencies and that decreases contractile function of unfatigued muscle in a dose-dependent manner. The present experiments test the hypothesis that NAC pretreatment can inhibit acute muscular fatigue in humans. Healthy volunteers were studied on two occasions each. Subjects were pretreated with NAC 150 mg/kg or 5% dextrose in water by intravenous infusion. The subject then sat in a chair with surface electrodes positioned over the motor point of tibialis anterior, an ankle dorsiflexor of mixed-fiber composition. The muscle was stimulated to contract electrically (40-55 mA, 0.2-ms pulses) and force production was measured. Function of the unfatigued muscle was assessed by measuring the forces produced during maximal voluntary contractions (MVC) of ankle dorsiflexor muscle groups and during electrical stimulation of tibialis anterior at 1, 10, 20, 40, 80, and 120 Hz (protocol 1). Fatigue was produced using repetitive tetanic stimulations at 10 Hz (protocol 1) or 40 Hz (protocol 2); intermittent stimulations subsequently were used to monitor recovery from fatigue. The contralateral leg then was studied using the same protocol. Pretreatment with NAC did not alter the function of unfatigued muscle; MVC performance and the force-frequency relationship of tibialis anterior were unchanged. During fatiguing contractions stimulated at 10 Hz, NAC increased force output by approximately 15% (P < 0.0001), an effect that was evident after 3 min of repetitive contraction (P < 0.0125) and persisted throughout the 30-min protocol. NAC had no effect on fatigue induced using 40 Hz stimuli or on recovery from fatigue. N-acetylcysteine pretreatment can improve performance of human limb muscle during fatiguing exercise, suggesting that oxidative stress plays a causal role in the fatigue process and identifying antioxidant therapy as a novel intervention that may be useful clinically.