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Ortega, DG, Housh, TJ, Smith, RW, Arnett, JE, Neltner, TJ, Schmidt, RJ, and Johnson, GO. The effects of anchoring a fatiguing forearm flexion task to a high versus low rating of perceived exertion on torque and neuromuscular responses. J Strength Cond Res38(5): e219–e225, 2024—This study examined the torque and neuromuscular responses following sustained, isometric, forearm flexion tasks anchored to 2 ratings of perceived exertion (RPE). Nine men (mean ± SD: age = 21.0 ± 2.4 years; height = 179.5 ± 5.1 cm; body mass = 79.6 ± 11.4 kg) completed maximal voluntary isometric contractions (MVIC) before and after sustained, isometric, forearm flexion tasks to failure anchored to RPE = 2 and RPE = 8. The amplitude (AMP) and mean power frequency (MPF) of the electromyographic (EMG) signal were recorded from the biceps brachii. Normalized torque was divided by normalized EMG AMP to calculate neuromuscular efficiency (NME). A dependent t-test was used to assess the mean difference for time to task failure (TTF). Repeated-measures analysis of variances was used to compare mean differences for MVIC and normalized neuromuscular parameters. There was no significant difference in TTF between RPE = 2 and RPE = 8 (p= 0.713). The MVIC decreased from pretest to posttest at RPE = 2 (p= 0.009) and RPE = 8 (p= 0.003), and posttest MVIC at RPE = 8 was less than that at RPE = 2 (p< 0.001). In addition, NME decreased from pretest to posttest (p= 0.008). There was no change in normalized EMG AMP or EMG MPF (p> 0.05). The current findings indicated that torque responses were intensity specific, but TTF and neuromuscular responses were not. Furthermore, normalized EMG AMP and EMG MPF remained unchanged but NME decreased, likely due to peripheral fatigue and excitation–contraction coupling failure. Thus, this study provides information regarding the neuromuscular responses and mechanisms of fatigue associated with tasks anchored to RPE, which adds to the foundational understanding of the relationship between resistance exercise and the perception of fatigue.

Anders, JPV, Neltner, TJ, Smith, RW, Arnett, JE, Housh, TJ, Schmidt, RJ, and Johnson, GO. Unilateral and bilateral isokinetic leg extensions exhibit no differences in neuromuscular activation under maximal and fatiguing conditions. J Strength Cond Res38(3): 474–480, 2024—The bilateral deficit is a phenomenon where force production during a bilateral (BL) muscle action is less than the sum of force produced when the muscle action is performed unilaterally (UL) with both limbs. The purpose of this study was to compare peak force, electromyographic (EMG) amplitude (AMP), and mean power frequency (MPF) of the nondominant leg between UL and BL isokinetic leg extensions. Eleven recreationally trained men (mean ± SD; age = 20.8 ± 1.7 years; body mass = 84.0 ± 16.2 kg; height = 179.3 ± 7.2 cm) volunteered to participate in this study. The 2 test visits included UL and BL maximal isokinetic leg extensions at 180°·second−1followed by a fatiguing task of either 50 UL or 25 UL followed immediately by 25 BL (ULBL) maximal, isokinetic leg extensions at 180°·second−1, in random order on separate days. The results demonstrated a significant (p= 0.015, ηp2= 0.460) bilateral deficit in force (UL = 56.29 ± 11.20 kg; BL = 50.32 ± 7.35 kg; d= 0.63; 95% CI [1.42, 10.52]) but no significant bilateral deficit in EMG AMP (p= 0.892, ηp2= 0.002). The peak force during the fatiguing task demonstrated a significant main effect for repetition (p< 0.001, ηp2= 0.943) characterized by a reduced peak force from repetitions 20–50. Similarly, EMG MPF demonstrated a significant main effect for repetition (p< 0.001, ηp2= 0.702) characterized by a reduced EMG MPF from repetitions 35–50. There were no significant effects (p= 0.102–0.387, ηp2= 0.096–0.203) for EMG AMP. These findings suggested that the bilateral deficit was not associated with a neuromuscular deficit and UL muscle actions may be used to potentiate force production of subsequent BL muscle actions.

Purpose: The purpose of this study was to examine the responses of electromyographic (EMG) and mechanomyographic (MMG) amplitude across the torque spectrum in pre- and post-pubescent males and females. Methods: Forty pre-pubescent (mean ± 95% confidence interval, age = 9.79 ± 0.35 years, n= 10 males, n= 10 females) and post-pubescent (age = 17.23 ± 0.58 years, n= 10 males, n= 10 females) participants completed this study. Participants completed maximal voluntary isometric contractions (MVICs) of the forearm flexors and extensors, as well as isometric ramp muscle actions. EMG and MMG amplitude were quantified from the biceps brachii, brachialis, and brachioradialis during all muscle actions. EMG and MMG amplitude during the isometric ramp muscle actions were normalized to EMG and MMG amplitude from the MVICs. Results: The pre-pubertal group tended to have greater relative EMG amplitude across intensity (P&lt; 0.050), while the post-pubertal group had a more pronounced increase in EMG amplitude at higher intensities. Similarly, the pre-pubertal group tended to have greater relative MMG amplitude across intensity (P≤ 0.004) that plateaued earlier than the post-pubertal group (55% vs. 65%–75% of MVIC). Additionally, the pre-pubertal group had greater coactivation across intensity (P≤ 0.001). Conclusion: The greater relative EMG and MMG amplitude in the pre-pubertal group, in conjunction with the earlier plateau in MMG amplitude for the pre-pubertal group and greater coactivation, suggests less efficient muscle activation and motor unit recruitment strategies during pre-pubescence. Taken together, the findings of the present study suggest that growth-mediated changes in neuromuscular function lead to improvements in the efficiency of muscular activation and augmentations in motor unit recruitment strategies.

The purpose of this investigation was to use the RPE clamp protocol to examine sex-related differences in performance fatigability and neuromuscular responses as the result of a sustained isometric leg extension muscle action anchored to RPE = 2. Twenty adults (10 men, 10 women) performed sustained muscle actions at RPE = 2 for 5-min. Maximal voluntary isometric contractions (MVIC) were performed prior to and following the sustained muscle actions. Neuromuscular (electromyographic and mechanomyographic) parameters and force were recorded, and the values were normalized to respective MVICs and calculated every 5% across the 5-min work bout. Femoral artery blood flow (FABF) was assessed at pretest, immediately posttest, and 5-min posttest. Polynomial regression was used to define the individual and composite normalized neuromuscular and force versus time relationships during the sustained muscle action. Mixed factorial ANOVAs were used to examine differences in performance fatigability and blood flow. For performance fatigability, the men (62.4 ± 14.4 kg–43.1 ± 11.5 kg) exhibited a significantly (P< 0.05) greater decrease pretest to posttest in MVIC than the women (44.1 ± 4.8 kg vs. 38.1 ± 6.1 kg). There were different fatigue-induced neuromuscular patterns of responses between the men and women across time. For blood flow responses, however, there was no sex-related difference, but pretest (283.3 ± 70.8 mL/min) was significantly (P< 0.05) less than immediately posttest (424.5 ± 133.5 mL/min) and 5-min posttest (324.4 ± 78.3 mL/min). Thus, men demonstrated a greater degree of performance fatigability than the women, which was independent of differences in FABF. Factors such as the neuromuscular system and muscle morphology likely contributed to the difference in performance fatigability.

Salmon, OF, Housh, TJ, Hill, EC, Keller, JL, Anders, JPV, Johnson, GO, Schmidt, RJ, and Smith, CM. Changes in neuromuscular response patterns after 4 weeks of leg press training during isokinetic leg extensions. J Strength Cond Res37(7): e405–e412, 2023—The purpose of this study was to identify velocity-specific changes in electromyographic root mean square (EMG RMS), EMG frequency (EMG MPF), mechanomyographic RMS (MMG RMS), and MMG MPF during maximal unilateral isokinetic muscle actions performed at 60° and 240°·s−1velocities within the right and left vastus lateralis (VL) after 4 weeks of dynamic constant external resistance (DCER) bilateral leg press training. Twelve resistance-trained men (age: mean ± SD= 21.4 ± 3.6 years) visited the laboratory 3d·wk−1to perform resistance training consisting of 3 sets of 10 DCER leg presses. Four, three-way analysis of variance were performed to evaluate changes in neuromuscular responses (EMG RMS, EMG MPF, MMG RMS, and MMG MPF) from the right and left VL during 1 single-leg maximal isokinetic leg extension performed at 60° and 240°·s−1before and after 4 weeks of DCER leg press training (p< 0.05). The results indicated a 36% increase in EMG RMS for the right leg, as well as a 23% increase in MMG RMS and 10% decrease in MMG MPF after training, collapsed across velocity and leg. In addition, EMG RMS was 65% greater in the right leg than the left leg following training, whereas EMG MPF was 11% greater for the left leg than the right leg throughout training. Thus, 4 weeks of DCER leg press training provides sufficient stimuli to alter the neuromuscular activation process of the VL but not velocity-specific neuromuscular adaptations in trained males.

Smith, RW, Housh, TJ, Anders, JPV, Neltner, TJ, Arnett, JE, Schmidt, RJ, and Johnson, GO. Application of the ratings of perceived exertion-clamp model to examine the effects of joint angle on the time course of torque and neuromuscular responses during a sustained, isometric forearm flexion to task failure. J Strength Cond Res37(5): 1023–1033, 2023—The present study used the ratings of perceived exertion (RPE)-clamp model during a sustained, isometric forearm flexion task to failure to determine the effects of joint angle on torque and neuromuscular responses. Twelve college-aged women performed two 3-second maximal voluntary isometric contractions at elbow joint angles (EJ) of 75°, 100°, and 125° before sustained, isometric, forearm flexions anchored to RPE = 7 to task failure (defined as RPE > 7, or the torque was reduced to zero) at EJ75, EJ100, and EJ125. The amplitude (AMP) and frequency (MPF) of the electromyographic (EMG) and mechanomyographic (MMG) signals from the biceps brachii were recorded. Repeated-measures ANOVAs and post hoc comparisons were used to examine differences across time and between joint angles for torque and neuromuscular parameters. A p-value ≤0.05 was considered significant. For each joint angle, there was a decrease (p< 0.05) in torque across the sustained, isometric task. Collapsed across joint angle, there were decreases (p< 0.001, ηp2= 0.378) in EMG AMP from 30 to 100% time to task failure. No changes were observed, however, for the other neuromuscular responses. The subjects voluntarily reduced torque to maintain RPE = 7 for each joint angle, and we hypothesize that RPE was maintained by afferent feedback from group III/IV motor neurons and corollary discharge (efferent copy of an internal signal that develops from central motor commands). The RPE-Clamp Model may be extended to athletes recovering from injury because a self-selected exercise intensity may be perceived as more enjoyable and promote adherence.

Giant cell tumors are uncommonly found within the craniofacial skeleton, and of those within the head and neck, are exceedingly rare in the maxilla. Here the authors present 2 cases of large, maxillary giant cell tumors: one presenting with mass-effect symptoms and another presenting from incidental findings on routine orthodontic care. Both patients were treated surgically with transoral and endoscopic transnasal excision and demonstrated favorable surgical results. One patient demonstrated no recurrence after 9 years and the other patient was disease free after 4 years. The authors end by discussing the role of emerging biologic agents, such as denosumab, for treating giant cell tumors of the jaws.

Neltner, TJ, Anders, JPV, Keller, JL, Smith, RW, Housh, TJ, Schmidt, RJ, and Johnson, GO. Velocity-specific coactivation and neuromuscular responses to fatiguing, reciprocal, isokinetic, forearm flexion, and extension muscle actions. J Strength Cond Res36(3): 649–660, 2022—The purpose of this study was to examine the effects of fatiguing, reciprocal, maximal, isokinetic, forearm flexion, and extension on coactivation. Ten recreationally trained women (mean ± SD: age = 21 ± 1.63 years) performed 50 maximal, reciprocal, isokinetic, forearm flexion, and extension muscle actions at 60 and 180°·s−1on separate days. Electromyographic (EMG) and mechanomyographic (MMG) signals from the biceps brachii (BB) and triceps brachii (TB) were recorded. A 2 (time) × 2 (velocity) × 2 (movement) and 4 separate 2 (time) × 2 (velocity) × 2 (muscle) × 2 (movement) repeated-measures analysis of variances were used to examine normalized torque and normalized EMG and MMG amplitude (AMP) and mean power frequency, respectively, with an alpha of p< 0.05. There were no significant interactions for torque but a main effect for time (p< 0.001, d= 3.29) such that it decreased. There was a significant four-way interaction for EMG AMP (p= 0.004, ηp2= 0.61) which revealed parallel responses between the BB and TB during both movements, with no changes at 60°·s−1and increases at 180°·s−1. The current findings suggested a common drive between agonist and antagonist muscles during fatiguing forearm flexion and extension muscle actions, with velocity-specific activation strategies. In addition, both EMG and MMG are viable techniques for assessing coactivation during fatiguing exercise.

The concept of disclosure of potential financial liabilities relating to environmental cleanup emerged in the 1970s. However, many corporations initially remained reluctant about including their responsibilities for remediation in their financial reports. Environmental disclosure appears to have improved in the 1990s, with 13 of the sample corporations in a study of environmental annual report coverage improving their environmental reporting. All seven criteria for environmental reporting also improved between 1991 and 1994 in the polled companies., Since the mid- 1970s, industrial corporations have struggled with the concept of reporting potential financial liabilities related to environmental cleanup. There has been a reluctance by corporations to recognize responsibilities [...]

Japanese business has entered a new management phase. Major corporations are changing their personnel practices by eliminating employee positions. This runs counter to a cultural foundation of Japanese business practices [...]

Keller, JL, Housh, TJ, Hill, EC, Smith, CM, Schmidt, RJ, and Johnson, GO. Are there sex-specific neuromuscular or force responses to fatiguing isometric muscle actions anchored to a high perceptual intensity? J Strength Cond Res36(1): 156–161, 2022—The purpose of this study was to use the ratings of perceived exertion (RPE) clamp model to examine sex-specific changes in neuromuscular responses and force after a sustained isometric leg extension muscle action anchored to RPE = 8. Twenty adults (10 men and 10 women) performed sustained, isometric leg extension muscle actions at RPE = 8. Electromyographic (EMG) and mechanomyographic signals were recorded from the dominant leg. Neuromuscular and force values resulting from the sustained muscle action were normalized to pretest maximal voluntary isometric contractions (MVICs). The level of significance set for the study was p≤ 0.05. The pretest MVIC was significantly (p< 0.001) greater (averaged across sex) than posttest MVIC force (55.5 ± 10.0 vs. 47.6 ± 11.1 kg). There was a significant (p< 0.01) decrease from pretest (95.4 ± 7.7 Hz) to posttest (76.2 ± 5.9 Hz) in EMG mean power frequency (MPF) for the men. The normalized force (averaged across sex) decreased significantly (p< 0.001) from the initial timepoint (57.1 ± 16.4%) to the final timepoint (44.3 ± 15.7%) of the sustained muscle action. Normalized EMG MPF (averaged across sex) decreased significantly (p= 0.001) from the initial timepoint (96.4 ± 17.5%) to final timepoint (87.8 ± 18.1%). The men and women exhibited similar fatigue-induced changes in force and neuromuscular parameters; therefore, these findings did not indicate different sex-specific responses after the fatiguing task anchored to a high perception of exertion. The force corresponding to RPE = 8 did not match the anticipated value; so, RPE and percentages of MVIC cannot be used interchangeably, and sustained isometric muscle actions anchored to RPE may elicit unique neuromuscular adaptations.

Purpose: The present study examined the effects of a reciprocal, slow velocity forearm flexion and extension task on fatigue-induced changes in isokinetic torque, agonist and antagonist muscle activation, and coactivation ratios at slow and moderate velocities. Methods: Nine women (mean ± SD: age = 21.0 ± 1.7 years; body mass = 68.1 ± 8.2 kg; height = 167.4 ± 7.2 cm) completed pre-testing for forearm flexion and extension isokinetic peak torque at 60 and 180°/s, a fatiguing task of 50 maximal, reciprocal, isokinetic muscle actions at 60°/s, and post-testing. The amplitude (AMP) of the electromyographic (EMG) signals from the biceps and triceps were simultaneously recorded. Torque and EMG AMP were normalized to the corresponding values from the pre-testing peak torque movements. Repeated measures ANOVAs and pairwise comparisons were used to identify mean changes in torque, EMG AMP, and coactivation ratios. Results: The torque analyses indicated significant decreases from pre- to post-testing for forearm flexion (14.1% ± 5.0%; P&lt; 0.001) and extension (25.4% ± 12.2%; P&lt; 0.001) at 60°. At 180°/s there was a significant decrease, collapsed across the forearm movements (24.7% ± 11.7%; P&lt; 0.001). For EMG AMP and coactivation ratios, there were no changes (P> 0.05) from pre- to post-testing for either velocity or movement. Conclusions: The torque responses were velocity-specific, with greater fatigability exhibited for forearm flexion versus extension at 60°/s, but no differences at 180°/s. The parallel EMG AMP responses between the agonist and antagonist muscles for both velocities supported the lack of fatigue-induced changes in coactivation ratios. Thus, our results demonstrated that fatigue-induced decreases in torque were not attributable to increases in antagonist activation or coactivation.

Net income is an enterprise performance measure favored by many financial statement users. However, several income items are not shown on the income statement. Numerous groups of financial statement users have called for revision of the number of income items that bypass the income statement. The accumulated balances of these items are currently reported in permanent equity accounts in the balance sheet, not on the income statement. Although discussed in U.S. accounting literature for over twenty years, the concept of a comprehensive income that captures these income items first became popular outside the United States. The first accounting standard addressing the issue was enacted in Europe. In 1992, the United Kingdom Accounting Standards Board issued Financial Reporting Standard 3 that introduced a statement of total recognized gains and losses as a supplement to the 'profit and loss statement' which is the U.S. income statement equivalent. In 1996, the International Accounting Standards Committee issued an exposure draft of a new income standard and modified it in 1997. It is conceptually similar to recent U.S. comprehensive income efforts. (Reprinted by permission of the publisher.), In the United States during 1980 and again in 1985, the Financial Accounting Standards Board defined comprehensive income in their Concepts Statements No. 3 and 6 as: Comprehensive income is [...]

A study examines any differences between estimates of critical torque (CT) and anaerobic work capacity (AWC) from two linear and two nonlinear mathematical models, and also compares the estimated time to exhaustion (ETTE) values associated with the CT estimates from the linear, nonlinear and exponential mathematical models. Results demonstrate that there are no differences between estimates of CT and AWC from the linear and nonlinear mathematical models, and that all five models overestimate the CT levels associated with estimated time to exhaustion (ETTE).

Participation in age group wrestling is not associated with age-related patterns of anthropometric characteristics distinct from a national sample of boys. Only the midthigh circumference was different between young wrestlers and non-wrestling boys.

A significant mean difference is found between the critical force and electromyograph fatigue threshold tests for the rectus femoris muscle. No significant electromyograph fatigue threshold values are found for the three superficial muscles of the quadriceps femoris.

Keller, JL, Housh, TJ, Smith, CM, Hill, EC, Schmidt, RJ, and Johnson, GO. Sex-related differences in the accuracy of estimating target force using percentages of maximal voluntary isometric contractions vs. ratings of perceived exertion during isometric muscle actions. J Strength Cond Res32(11): 3294–3300, 2018—The purpose of this study was to examine sex-related differences in the accuracy of estimating actual target force and to compare the accuracy of estimating actual target force using percentages of maximal voluntary isometric contraction (MVIC) or ratings of perceived exertion (RPE) values during isometric leg flexion and leg extension muscle actions. Twenty adults, 10 women and 10 men, (mean ± SDage: 22.9 ± 2.9 years) completed pretest MVICs to calculate actual target force values at 10, 30, 50, 70, and 90% of MVIC. Additional trials were then randomized for estimating actual target force using percentages of MVIC or RPE values during isometric leg flexion or leg extension. For isometric leg flexion, the women and men overestimated (p≤ 0.05) the actual target force at 10% for the percentage of MVIC and RPE trials and underestimated the actual target force at 90% for the RPE trial. For isometric leg extension, the women overestimated the actual target force at 10% for the percentage of MVIC trial and RPE trial. The men overestimated actual target force at 10 and 30% for the percentage of MVIC trial and overestimated actual target force at 10% during the RPE trial for isometric leg extension. Also, the men underestimated actual target force at 90% for both the percentage of MVIC trial and RPE trial. Men require more familiarization than women to accurately estimate isometric leg extension force values. Caution should be used when estimating force production as a percentage of MVIC or RPE value for training prescriptions.

Current capabilities of accurately predicting the behavior of the various subassemblies of lightframe wood structures walls, floors, and roofs now meet or exceed the ability to characterize material properties. However, subassembly analysis techniques are not commonly incorporated in design practice. The deficiency lies in the inability to efficiently predict the interaction of the subassemblies which yields the behavior of the entire structure. The purpose of this study is to develop and validate a simple structural analysis model to predict the behavior of lightframe buildings under lateral load. The model is limited to the racking response of shear walls that are arranged in a rectangular fashion beneath a rigid ceilingfloor diaphragm. Nonlinear loadslip behavior of fasteners is utilized in an energy formulation to yield a threedegreeoffreedom representation of each story of the building. Predicted behavior from the analysis model agrees favorably with results from fullscale tests. The model provides a method for estimating the behavior of lightframe buildings near lateral loading and should lead to realistic shear wall strength and stiffness requirements for both residential and commercial buildings.

Conservative management of complicated esophageal perforations has gained favor in recent years. However, there are limited data concerning the applicability of this approach in the pediatric population. We describe the care and outcome of a 14‐year‐old girl who sustained an esophageal perforation after accidental ingestion of a shard of glass. The patient was treated using ultrasound‐guided drainage catheter placement with simultaneous esophagoscopy and postoperative antibiotics. She was discharged within 1 week of presentation and enjoyed an uncomplicated recovery. We believe that selected cases of pediatric esophageal perforation may be safely and effectively treated using a conservative approach.

The effects of various monosaccharides on the growth of human 2002 and mouse L929 fibroblast cultures have been investigated. Eleven monosaccharides having acidic, neutral, and basic characteristics were evaluated in a bioassay procedure developed for the investigation of biocompatibility of wound management materials. Rate of growth in both cell lines was inhibited by D-galacturonic acid and by D-glucuronic acid. Although most neutral sugars produced no significant change in the growth rate or in the morphology of the cells, galactose produced a significant increase in the growth rate of both cell lines whilst L-fucose caused a significant decrease in growth of the L929 cells but did not significantly affect the growth of 2002 cells; xylose increased the growth rate of L929 but not 2002 cells. D-Glucosamine, a basic sugar, produced inhibition of growth which followed a different pattern from that produced by the acidic sugars; N-acetylglucosamine produced a species specific increase in cell growth of L929 cells. The results show that the effects produced by the monosaccharides on the cultured fibroblasts are related to their chemical structure and to cell line, and suggest that the use of galactose as a possible aid to wound healing should be investigated.

To facilitate the development of a bioassay procedure by which the biocompatibilities of materials used in wound management may be assessed and compared, those environmental factors affecting cell growth in mouse L929 fibroblast cultures have been identified. Standardization of the initial cell number and frequency of change of medium resulted in the virtual elimination of variation of growth curves of L929 cells cultured in flasks of specified surface area. In addition, three methods for assessing fibroblast growth rate in the presence of alginate products used in wound management were evaluated. These were the haemacytometer counting chamber method, the Coulter counting method, and a liquid scintillation counting method. The first two methods determine the number of cells in a given volume of a cell suspension, whereas the third method determines the rate of synthesis of deoxyribonucleic acid (DNA), and hence cell growth, by measuring the incorporation of [3H]thymidine. The haemacytometer method had significant advantages over the other two procedures in providing both qualitative and quantitative data on culture morphology and cell growth response.

An in-vitro screening method to examine the biocompatibility of materials used in wound management has been evaluated. This involved the use of a macrophage respiratory-burst assay and a fibroblast proliferation assay to represent respectively the inflammatory and the granulation phases in wound healing. Standard polysaccharides (calcium and sodium alginates, ŗ-carrageenan, chitin, chitosan lactate, chondroitin sulphate and pectic acid) were used as test compounds. None of the polysaccharide samples caused a significant increase in L929 fibroblast cell numbers relative to control after 6 days incubation. The overall effect of exposure of the fibroblast cultures to the alginates, carrageenan and chondroitin sulphate was an extension of lag phase followed by an enhanced rate of cell proliferation in the logarithmic phase. Only calcium and sodium alginates and chondroitin sulphate enhanced the respiratory burst activity of murine macrophages; ŗ-carrageenan and chitosan lactate were markedly inhibitory. The results suggest that a macrophage activity assay should be included as part of an in-vitro screening program to evaluate the biocompatibility of wound management materials and to detect intrinsic biological activity.

A series of esters were produced by partial synthesis from 9,13,14-orthophenylacetyl-resiniferonol. These compounds were tested for irritant effects by means of a mouse ear assay. All of the derivatives, including the parent compound, produced short-term inflammation of mice ears within 1–2 h and the effects did not persist for 24 h. This is in contrast to esters of structurally related tigliane diterpenes which produce a longer-term effect on mice ears. Highly potent irritants were synthesized which exhibited irritant doses 50% in the 0.0012–0.00021 nmol range. These esters were all substituted phenylacetates of the C-20 position of 9,13,14-orthophenylacetyl-resiniferonol. The meta or para positions of the phenylacetate moiety were substituted with electronegative groups for maximum activity. Compounds exhibiting substituted phenyl propionates at C-20 were not irritants in the test used.

A method is described for testing of diterpene esters for irritancy. The technique involves the application of acetone solutions of the toxins to the inside ears of female LACA mice. The number of mice responding per group and the log10 dose data were evaluated using probit analysis with the assistance of a computer program. This evaluation has the advantage that approximations inherent with an arithmetical evaluation were eliminated, and limits may be placed upon the standard deviation of the irritant dose 50% (ID50). In addition, the use of a ?2 test automatically eliminated results which were not attributed to random biological variation. Observations of the time to onset and the persistence of the inflammation have led to the suggestion that daphnane orthoester diterpenes may elicit their effect by means of a direct action at a receptor site in skin, whereas the tiglianeO-acyl esters may in part act by causing more general tissue damage.

ABSTRACT

The purposes of this study were to (1) determine and compare the cardiovascular (CV) responses (i.e., exercise and recovery heart rate and recovery blood pressure) to weight training (WT) exercise and a graded exercise test (GXT) on a cycle ergometer, and (2) to determine and compare the exercise and recovery heart rate (HR) and recovery blood pressure characteristics to several intensities of WT exercise. Nineteen weight-trained men (mean age = 24.5 ± 2.9 yr) performed the squat WT exercise for sets of 10 repetitions at 50%, 60%, 70%, 80%, 90%, and 100% of their 10 repetition maximum (RM). HR was continuously monitored, and systolic (SBP) and diastolic (DBP) blood pressures, and rate pressure product (RPP; HR × SBP × 0.01) were recorded at T1 (15–30 sec postexercise), T2 (1 min postexercise), T3 (2 min postexercise), and T4 (3 min postexercise). Maximal mean CV responses at T1 during WT were: HR = 154.1 ± 20.8 bpm (during 100% 10 RM), SBP = 172.8 ± 19.2 mmHg (90% 10 RM), DBP = 88.8 ± 8.2 mmHg (60% 10 RM), and RPP = 259.3 ± 44.5 (100% 10 RM). On a separate day, all subjects performed a discontinuous GXT while the same CV variables were recorded at T1. Mean maximal exercise responses at T1 during the GXT were: HR = 161.5 ± 15.6 bpm, SBP = 190.6 ± 25.6 mmHg, DBP = 82.9 ± 8.9 mmHg, and RPP = 307.4 ± 51.4. For WT, HR, SBP, and RPP were always significantly less (p ≤ 0.05) than the values for the GXT, except for HR at T1 of 100% 10 RM intensity, which was similar to the GXT T1 values. WT DBP at T1 was always significantly greater than GXT DBP, but the differences appeared to be of little physiological importance. Recovery WT responses (T1 – T4) showed consistent decreases across time for HR and RPP. WT DBP increased slightly, but significantly after all WT intensities. It was determined that, in response to WT, the HR responses during exercise and recovery, and the SBP and RPP responses during recovery were generally less than or equal to the respective responses to a discontinuous GXT. Although the DBP responses to WT were greater than the responses to the GXT, it was determined that the differences were small enough to be of little physiological importance.

The purpose of this investigation was to examine times to exhaustion at various percentages of the electromyographic fatigue threshold (EMGFT). Eight adult males [mean (SD), 21 (1) years] volunteered for the investigation. EMGFT was derived by determining the rate of rise in the electrical activity of the vastus lateralis [using integrated electromyography (iEMG)] over time (iEMG slope) for four fatiguing power outputs during cycle ergometry. The four power outputs were then plotted as a function of the four iEMG slope coefficients. The y-intercept of the power output versus iEMG slope coefficient graph was defined as the EMGFT. The intraclass correlation for repeated EMGFT tests was R=0.65 (SEE=7 W) and there was no significant (P>0.05) difference between the mean (SD) values for test [260 (11) W] versus retest [262 (32) W]. Actual times to exhaustion were determined for work bouts at power outputs equal to 85, 100, 115, 130, and 145% of EMGFT. The mean (SD) times to exhaustion for these work bouts were 495 (231), 225 (72), 135 (35), 94 (17), and 72 (14) s, respectively. A power curve was derived using the mean power outputs and mean times to exhaustion from the five rides at various percentages of EMGFT. The power curve provided estimates of the power outputs which could be maintained for 30 and 60 min. There were significant (P<0.05) differences between the mean EMGFT (260 W) and the power outputs which could be maintained for 30 (151 W) and 60 (125 W) min. EMGFT overpredicted the estimated power outputs that could be maintained for 30 and 60 min by 42% and 52%, respectively.

The skin irritant potencies of several naturally occurring and semisynthetic polyfunctional esters based on the tigliane hydrocarbon skeleton were studied using a mouse ear irritancy assay. The compounds used were esters of 12-deoxyphorbol, 12-deoxy-16-hydroxyphorbol, and phorbol. Observations were also made on the time interval between application of these compounds in acetone solution to the mouse ear, and the attainment of maximum response. Structure/activity relationships are discussed and compared with previous observations on the skin irritant potencies of esters based on the closely related daphnane hydrocarbon skeleton. The possible nature of the site of action in the target membrane is also discussed.

Agaricus bisporus, Fusarium graminearum, Phycomyces blakesleeanus, unbleached and bleached, Rhizomucor miehei, and Rhizopus oryzaewere examined as sources of fungal chitin/chitosan. The nitrogen content of the alkali-treated mycelia/sporangiophores obtained after optimization of culture conditions, and of similarly treated A. bisporusstipes, was 2.87, 1.29, 6.27, 6.50, 4.80, and 4.95% w/w, respectively, which relates to an estimated chitin content of 42, 19, 91, 94, 70, and 72%, respectively. The hydrogen peroxide (H2O2)-generating ability of the treated fungal materials after 8 h at pH 7.4 and 37°C decreased in the order R. oryzae> P. blakesleeanusunbleached ˜ R. miehi> F. graminearum> A. bisporus> P. blakesleeanusbleached. This did not correlate with estimated chitin content. The effect of these fungal materials on the rate of proliferation of murine L929 fibroblasts in culture also was examined. Both pro- and antiproliferant effects were observed. Significant (P< .05) proproliferant effects were observed on day 6 with R. miehei, R. oryzae, and P. blakesleeanus(unbleached and bleached) at 0.01% w/v. The greatest antiproliferant effect was observed with R. oryzaeat 0.05% w/v on day 6 (-63% relative to the control, P< .05; cell viability, 95%). In contrast, A. bisporusfailed to affect cell yield significantly at either 0.01 or 0.05% w/v. Addition of catalase to cultures containing R. oryzaeor R. mieheiat 0.05% w/v failed to abolish the antiproliferant effect on day 3, instead producing a small but significant (P< .05) increase in the effect. Catalase also failed to affect significantly the antiproliferant effect of F. graminearumat 0.05% w/v, but did abolish the proproliferant effect of P. blakesleeanus(unbleached and bleached) on day 3. Overall, our results suggest that the H2O2being generated by the fungal materials modulates cell proliferation but that this effect is superimposed upon a H2O2-independent antiproliferant effect manifesting itself at the higher concentrations of fungal material. The antiproliferant effect was not attributable to Ca2+, Mg2+, or Fe2+depletion although chelation of Fe2+did correlate with H2O2-generating ability. Only P. blakesleeanusappears to lack this antiproliferant activity while retaining H2O2-generating activity. These results may aid the selection of fungal chitin/chitosan for further evaluation as a potential wound management material. © 1998 John Wiley & Sons, Inc. J Biomed Mater Res, 39, 300–307, 1998.

By virtue of its approximately 20,000 species, the plant family Compositae (which is also known as the Asteraceae) is surpassed in size only by the family Orchidaceae. Representatives of the Compositae are found in most regions of the world, but are rare in tropical rain forests. In form, they are mostly herbaceous plants; a small proportion are trees; only a few climbers, water and marsh plants, and epiphytes are known.1

The most frequently used approach for representing the constitutive relations for anisotropic materials is Hill's incremental plasticity model. However, a fundamental difficulty with the use of Hill's plasticity model is the need to select a unique effective stress‐effective strain relation when none truly exists. Recently, an alternative model based upon stress invariants that does not require definition of an effective stress‐effective strain relation has been proposed. In this study, the invariant‐based model and Hill's model are implemented in a general finite element system. The invariant‐based model is reviewed and a modification is proposed that improves performance for certain multiaxial stress states. Performance of the modified invariant‐based model relative to Hill's model is measured. Comparisons are based upon finite element micromechanics analysis and experimental test results. The invariant‐based model is shown to be superior to Hill's model for a variety of uniaxial and multiaxial loading conditions, but this model is limited to predicting inelastic behavior of transversely isotropic materials.

An account is provided of the history and planned development of BoDD: Botanical Dermatology Database, a major Internet resource.

A semiquantitative assay procedure for the estimation of uptake of diethylamine by activated carbon dressings has been developed. The procedure involves the use of Nessler’s reagent as a comparative indicator. The use of diethylamine allows the concomitant detection of silver with which the dressings may be impregnated. The implications of silver/amine complex formation during dressing use are discussed. Quantification of the silver content of one such fabric was carried out by atomic absorption spectrophotometry. A silver content of 2770 ppm was found. It is suggested that this method might be suitable for adoption as the basis for a pharmacopoeial assay procedure for activated carbon dressings.

This is a case of an 11-year-old male with an ethmoid sinus mucocele who presented to our emergency department with an orbital mass. This mucocele was most likely related to an ipsilateral orbital subperiosteal abscess that required endoscopic drainage 9years ago. Mucoceles are mucus-filled, epithelial-lined sacs that slowly develop in the paranasal sinuses when sinus drainage is obstructed by inflammatory processes, trauma, or prior surgery. They are rare in children and should be suspected in patients with progressive headache or orbital complaints.