Assigned Versus Random,Countermeasure-Like Responses in the P300 Based Complex Trial Protocol for Detection of Deception: Task Demand Effects

We recently introduced an accurate and countermeasure resistant P300-based deception detection test called the complex trial protocol (Rosenfeld et al. in Psychophysiology 45(6):906–919, 2008). When subjects use countermeasures to all irrelevant items in the test, the probe P300 is increased rather than reduced (as it was in previous P300-based deception protocols), allowing detection of countermeasure users. The current experiment examines the role of task demand on the complex trial protocol by forcing the subject to make countermeasure-like response to stimuli. Subjects made either a simple random button response to both probe and irrelevant stimuli (experiment 1) or a more complex, assigned, button response to probe and irrelevant stimuli (experiment 2). We found that an increase in task demand reduced the effectiveness of the test. Using random responses we found a simple guilty hit rate of 11/12 with no false positives, but only a 4/11 hit rate for countermeasure-users. Using assigned responses we found a simple guilty hit rate of 8/15 with no false positives, and a 7/16 hit rate for countermeasure-users. We herein suggest that the high level of task demand associated with these countermeasure-like responses causes reduced hit rates.     

P900: A Putative Novel ERP Component that Indexes Countermeasure Use in the P300-Based Concealed Information Test

Countermeasures pose a serious threat to the effectiveness of the Concealed Information Test (CIT). In a CIT experiment, Rosenfeld and Labkovsky in Psychophysiology 47(6):1002–1010, (2010) observed a previously unknown positive ERP component at about 900 ms post-stimulus at Fz and Cz that could potentially serve as an index of countermeasure use. Here, we explored the hypothesis that this component, termed P900, occurs in response to a signal that no further specific response is required in a trial, and could thus appear in countermeasure users that respond differentially depending on the stimulus that appears. In the present experiments, subjects viewed four non-meaningful (irrelevant) dates and one oddball date. In three experiments, we examined P900’s antecedent conditions. In the first, the unique item was a personally relevant oddball (the subject’s birthdate). In a second, the unique item was a non-personally relevant oddball (an irrelevant date in a unique font color). In a third, all dates were irrelevant. We speculated that the presence of an oddball would not be necessary for P900. All participants made countermeasure-like responses following two specific irrelevant dates. As hypothesized, P900s were seen to non-responded-to irrelevant and oddball stimuli in all subjects but not to responded-to irrelevant stimuli, and the presence of an oddball was not necessary for elicitation of P900. This finding has potential application in deception settings—the presence of a P300 accompanied by the presence of a P900 in response to non-countered stimuli could provide evidence of incriminating knowledge accompanied by the attempt to use countermeasures to evade detection.     

Induced angiogenesis with intramedullary direct current: experimental research

The purpose of this study was to evaluate angiogenesis after the use of intramedullary direct electrical current in rabbit tibia. Thirty-two New Zealand rabbits were divided into four groups: group 1, false electrode group; group 2, hole group; group 3, control group; and group 4, intramedullary electrical stimulation group. One-half of the rabbits in each group were evaluated angiographically, pathologically, and scintigraphically on day 7, and the rest were evaluated on day 21. Results proved that electrical stimulation was not capable of the induction of angiogenesis in the subjects killed on day 7 and day 21. Furthermore, we found some fibrotic changes secondary to electrical stimulation on day 7 (P = 0.04) and day 21 (P = 0.01). However, an increase in new capillary vessels occurred in the false electrode group (P = 0.02). We found no useful effect of electrical stimulation in our study, a finding that is possibly due to our use of a method previously undocumented in the literature. We believe that this study can be the new baseline for further studies into the stimulation or inhibition of angiogenesis using intramedullary wire with or without electrical stimulation.     

Strength outcomes in fixed versus free-form resistance equipment

The purpose of this study was to compare measures of strength and balance between subjects using fixed form or free-form resistance training equipment to determine whether there is a difference in strength or balance outcomes. Thirty previously untrained subjects, mean age = 49 (+/-3.7 years), were randomly placed in either a free-form strength group (FF n = 10) utilizing a commercially available free-form plate loaded resistance device, a fixed form strength group (FX n = 10) utilizing a commercially available fixed range selectorized resistance device or a control group (C; n = 10) who did not exercise. All groups were assessed during a pretest (T1) and a posttest (T2). The exercise groups were asked to exercise over a 16-week period, increasing resistance based on a standardized 8-12 repetition protocol. The same muscles were targeted in both exercise groups, all groups were instructed not to change their dietary habits. A one-way ANOVA was used to detect differences among the groups using baseline and end results data. FX group increased strength 57% from baseline while the FF group increased strength 115% from baseline. A statistically significant difference (P = 0.000001) was detected for strength production in the FF over the FX group and (P = 0.0000144) over the training and control groups. Balance improved 49% in the FX versus 245% in the FF groups. Testing revealed a statistically significant difference (P < or = 0.003). The control (C) group did not show significant improvement in either strength or balance. Results of this study indicate a greater improvement in FF over FX in strength (58%), and balance (196%). Additionally, the FX reported increased pain levels while the FF group reported lowered overall pain levels.     

A Novel Algorithm to Enhance P300 in Single Trials: Application to Lie Detection Using F-Score and SVM

The investigation of lie detection methods based on P300 potentials has drawn much interest in recent years. We presented a novel algorithm to enhance signal-to-noise ratio (SNR) of P300 and applied it in lie detection to increase the classification accuracy. Thirty-four subjects were divided randomly into guilty and innocent groups, and the EEG signals on 14 electrodes were recorded. A novel spatial denoising algorithm (SDA) was proposed to reconstruct the P300 with a high SNR based on independent component analysis. The differences between the proposed method and our/other early published methods mainly lie in the extraction and feature selection method of P300. Three groups of features were extracted from the denoised waves; then, the optimal features were selected by the F-score method. Selected feature samples were finally fed into three classical classifiers to make a performance comparison. The optimal parameter values in the SDA and the classifiers were tuned using a grid-searching training procedure with cross-validation. The support vector machine (SVM) approach was adopted to combine with an F-score because this approach had the best performance. The presented model F-score_SVM reaches a significantly higher classification accuracy for P300 (specificity of 96.05%) and non-P300 (sensitivity of 96.11%) compared with the results obtained without using SDA and compared with the results obtained by other classification models. Moreover, a higher individual diagnosis rate can be obtained compared with previous methods, and the presented method requires only a small number of stimuli in the real testing application.     

Real-time assessment of postprandial fat storage in liver and skeletal muscle in health and type 2 diabetes

Liver and skeletal muscle triglyceride stores are elevated in type 2 diabetes and correlate with insulin resistance. As postprandial handling of dietary fat may be a critical determinant of tissue triglyceride levels, we quantified postprandial fat storage in normal and type 2 diabetes subjects. Healthy volunteers (n = 8) and diet-controlled type 2 diabetes subjects (n = 12) were studied using a novel 13C magnetic resonance spectroscopy protocol to measure the postprandial increment in liver and skeletal muscle triglyceride following ingestion of 13C-labeled fatty acids given with a standard mixed meal. The postprandial increment in hepatic triglyceride was rapid in both groups (peak increment controls: +7.3 +/- 1.5 mmol/l at 6 h, P = 0.002; peak increment diabetics: +10.8 +/- 3.4 mmol/l at 4 h, P = 0.009). The mean postprandial incremental AUC of hepatic 13C enrichment between the first and second meals (0 and 4 h) was significantly higher in the diabetes group (6.1 +/- 1.4 vs. 1.7 +/- 0.6 mmol x l(-1) x h(-1), P = 0.019). Postprandial increment in skeletal muscle triglyceride in the control group was small compared with the diabetic group, the mean 24-h postprandial incremental AUC being 0.2 +/- 0.3 vs. 1.7 +/- 0.4 mmol x l(-1) x h(-1) (P = 0.009). We conclude that the postprandial uptake of fatty acids by liver and skeletal muscle is increased in type 2 diabetes and may underlie the elevated tissue triglyceride stores and consequent insulin resistance.     

Evaluation of four methods of DNA recovery from Mycobacterium avium subspecies paratuberculosis present in intestine tissue of goats and comparative sensitivity of IS900 PCR with respect to culture for diagnosis of Johne's disease

Low sensitivity of PCR reaction for detection of Mycoobacterium avium subspecies paratuberculosis (MAP) in tissues and fecal samples is mainly attributed to false negative results. Present study was undertaken to compare four methods of DNA isolation from tissues of infected animals and to determine most sensitive protocol for the recovery of DNA, suitable for IS900 PCR based detection of Johne's disease infection. Method I, the traditional van Soolingen2 method of DNA isolation was adopted for the isolation of DNA from tissues. Method II was modification (hexadecyl pyridinium chloride-HPC treatment) of van Soolingen2 method. Method III was traditional tissue DNA isolation method based on tissue lysis buffer. Method IV was modification of method III (HPC treatment). Using four methods of DNA isolation from 25 intestinal tissues of clinically infected goats, DNA was isolated from 15 (60.0%), 18 (72.0%), 13 (52.0%) and 13 (52.0%) tissues using method I, II, III and IV, respectively. All isolated DNA preparations were positive for MAP in IS900 PCR. HPC treatment enhanced the recovery of DNA from tissues of infected animals using method II. Therefore, method II can improve the diagnosis MAP infection using IS900 PCR.     

The use of estradiol and/or GnRH in a two-dose PGF protocol for breeding management of beef heifers

The objective was to determine reproductive performance following AI in beef heifers given estradiol to synchronize ovarian follicular wave emergence and estradiol or GnRH to synchronize ovulation in a two-dose PGF-based protocol. In Experiment 1, 561 cycling (confirmed by ultrasonography), Angus heifers received 500 microg cloprostenol, i.m. (PGF) twice, 14 days apart (days 0 and 14) and were equally allocated to four groups in a 2 x 2 factorial design. On Day 7, heifers received either 2 mg estradiol benzoate (EB) and 50 mg progesterone (P), i.m. in oil (EBP group) or no treatment (NT group). Half the heifers in each group received 1mg EB, i.m. in oil on Day 15 (24h after the second PGF treatment) with TAI 28 h later (52 h after PGF), and the other half received 100 microg GnRH, i.m. on Day 17 (72 h after PGF) concurrent with TAI. All heifers were observed for estrus twice daily from days 13 to 17; those detected in estrus more than 16 h before scheduled TAI were inseminated 4-16 h later and considered nonpregnant to TAI. Overall pregnancy rate (approximately 35 days after AI) was higher in heifers that received EBP than those that did not (61.6% versus 48.2%, respectively; P < 0.002); but was lower in heifers that received EB after PGF than those that received GnRH (50.0% versus 59.8%; P < 0.02). Although estrus was detected prior to TAI in 77 of 279 heifers (27.6%) treated with EBP (presumably due to induced luteolysis), they were inseminated and 53.2% became pregnant. Overall pregnancy rates were 51.4, 68.3, 45.0, and 55.0% in the NT/GnRH, EBP/GnRH, NT/EB, and EBP/EB groups, respectively (P < 0.05). In Experiment 2, 401 cycling, Angus heifers were used. The design was identical to Experiment 1, except that 1.5mg estradiol-17beta (E-17beta) plus 50mg progesterone (E-17betaP) and 1mg E-17beta were used in lieu of EBP and EB, respectively. All heifers receiving E-17beta 24h after the second injection of PGF (NT/E-17beta and E-17betaP/E-17beta) were TAI 28 h later without estrus detection, i.e. 52 h after PGF. Heifers in the other two groups received 100 microg GnRH, i.m. 72 h after PGF and were concurrently TAI; heifers in these two groups that were detected in estrus prior to this time were inseminated 4-12h later and considered nonpregnant to TAI. Estrus rate during the first 72 h after the second PGF treatment was higher (P < 0.05) in the E-17betaP/GnRH group (45.0%; n = 100) than in the NT/GnRH group (16.0%; n = 100), but conception rate following estrus detection and AI was not different (mean, 57.4%; P = 0.50). Overall pregnancy rate was not significantly different among groups (mean, 46.9%; P = 0.32). In summary, the use of EB or E-17beta to synchronize follicular wave emergence and estradiol or GnRH to synchronize ovulation in a two-dose, PGF-based protocol resulted in acceptable fertility to TAI. However, when 2mg EB was used to synchronize follicular wave emergence, early estrus occurred in approximately 28% of heifers, necessitating additional estrus detection. A combination of estrus detection and timed-AI in a two-dose PGF protocol resulted in highly acceptable pregnancy rates.     

Application of DNA analysis in a population-screening program for neonatal diagnosis of cystic fibrosis (CF): comparison of screening protocols.

We compare two protocols for newborn screening for cystic fibrosis (CF). The first uses the immunoreactive trypsinogen (IRT) assay with a cutoff of > or = 180 ng/ml and a sweat test to identify CF patients. The second uses the IRT assay with a 100 ng/ml cutoff in conjunction with direct analysis for the delta F508 CF transmembrane conductance regulator (CFTR) mutation in a two-tiered (i.e., IRT/DNA) protocol, followed by a sweat test. We screened 220,865 newborns from Wisconsin for CF, using the IRT protocol identifying 369 infants with an elevated IRT, of whom 46 were found to have CF. Another 7 CF patients were identified who had a false-negative IRT level. The CF incidence in the white population was 1 in 3,431 (carrier incidence of 1 in 30). The IRT protocol had a sensitivity of 87% and a positive predictive value of 12.5%. We subsequently used the IRT/DNA protocol to screen 21,258 infants. Of 518 infants with an IRT level > or = 100 ng/ml, 24 carried at least one copy of the delta F508 CFTR mutation, and 4 of these infants were found to have CF, yielding a positive predictive value for this protocol of 16.7%. Direct comparison of the positive predictive value of the two protocols is not valid, because of the different populations screened. However, had the IRT protocol been used on the IRT/DNA cohort, 50 infants, including the 4 with CF, would have received sweat tests, yielding a positive predictive value of 8%. Because of the small sample size, this positive predictive value is not significantly different from that obtained for the IRT/DNA test. However, from a practical point of view the IRT/DNA approach does decrease considerably the number of sweat tests that must be undertaken. The number of false positives for the IRT protocol (46 in 21,258) is increased significantly compared with that for the IRT/DNA approach (20 in 21,258; P < .001). The incidence of delta F508 carriers detected in cohorts with an elevated IRT level was increased compared with the incidence in the general population. The direct costs for the IRT/DNA approach (100 ng/ml) were $11,374 per CF patient detected, compared with $10,187 per CF patient detected for the IRT protocol. Therefore, we conclude that the IRT/DNA approach to CF newborn screening decreases the number of false-positive subjects contacted, without a significant increase in cost.     

Combined aerobic and resistance training and vascular function: effect of aerobic exercise before and after resistance training.

Aerobic exercise training combined with resistance training (RT) might prevent the deterioration of vascular function. However, how aerobic exercise performed before or after a bout of RT affects vascular function is unknown. The present study investigates the effect of aerobic exercise before and after RT on vascular function. Thirty-three young, healthy subjects were randomly assigned to groups that ran before RT (BRT: 4 male, 7 female), ran after RT (ART: 4 male, 7 female), or remained sedentary (SED: 3 male, 8 female). The BRT and ART groups performed RT at 80% of one repetition maximum and ran at 60% of the targeted heart rate twice each week for 8 wk. Both brachial-ankle pulse wave velocity (baPWV) and flow-mediated dilation (FMD) after combined training in the BRT group did not change from baseline. In contrast, baPWV after combined training in the ART group reduced from baseline (from 1,025 +/- 43 to 910 +/- 33 cm/s, P < 0.01). Moreover, brachial artery FMD after combined training in the ART group increased from baseline (from 7.3 +/- 0.8 to 9.6 +/- 0.8%, P < 0.01). Brachial artery diameter, mean blood velocity, and blood flow in the BRT and ART groups after combined training increased from baseline (P < 0.05, P < 0.01, and P < 0.001, respectively). These values returned to the baseline during the detraining period. These values did not change in the SED group. These results suggest that although vascular function is not improved by aerobic exercise before RT, performing aerobic exercise thereafter can prevent the deteriorating of vascular function.     

Progressive resistance training without volume increases does not alter arterial stiffness and aortic wave reflection

Endurance exercise is efficacious in reducing arterial stiffness. However, the effect of resistance training (RT) on arterial stiffening is controversial. High-intensity, high-volume RT has been shown to increase arterial stiffness in young adults. We tested the hypothesis that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume would not elicit increases in either central or peripheral arterial stiffness or alter aortic pressure wave reflection in young men and women. The RT group (n = 24; 21 +/- 1 years) performed two sets of 8-12 repetitions to volitional fatigue on seven exercise machines on 3 days/week for 12 weeks, whereas the control group (n = 18; 22 +/- 1 years) did not perform RT. Central and peripheral arterial pulse wave velocity (PWV), aortic pressure wave reflection (augmentation index; AIx), brachial flow-mediated dilation (FMD), and plasma levels of nitrate/nitrite (NOx) and norepinephrine (NE) were measured before and after RT. RT increased the one-repetition maximum for the chest press and the leg extension (P < 0.001). RT also increased lean body mass (P < 0.01) and reduced body fat (%; P < 0.01). However, RT did not affect carotid-radial, carotid-femoral, and femoral-distal PWV (8.4 +/- 0.2 vs. 8.0 +/- 0.2 m/sec; 6.5 +/- 0.1 vs. 6.3 +/- 0.2 m/sec; 9.5 +/- 0.3 vs. 9.5 +/- 0.3 m/sec, respectively) or AIx (2.5% +/- 2.3% vs. 4.8% +/- 1.8 %, respectively). Additionally, no changes were observed in brachial FMD, NOx, NE, or blood pressures. These results suggest that an RT protocol consisting of progressively higher intensity without concurrent increases in training volume does not increase central or peripheral arterial stiffness or alter aortic pressure wave characteristics in young subjects.     

Artificial gravity with ergometric exercise preserves the cardiac, but not cerebrovascular, functions during 4 days of head-down bed rest

Cardiovascular and musculoskeletal deconditioning occurring in long-term spaceflight requires new strategies to counteract these adverse effects. We previously reported that a short-arm centrifuge produced artificial gravity (AG), together with ergometer, has an approving effect on promoting cardiovascular function. The current study sought to investigate whether the cardiac and cerebrovascular functions were maintained and improved using a strategy of AG combined with exercise training on cardiovascular function during 4-day head-down bed rest (HDBR). Twelve healthy male subjects were assigned to a control group (CONT, n=6) and an AG combined with ergometric exercise training group (CM, n=6). Simultaneously, cardiac pumping and systolic functions, cerebral blood flow were measured before, during, and after HDBR. The results showed that AG combined with ergometric exercise caused an increase trend of number of tolerance, however, there was no significant difference between the two groups. After 4-day HDBR in the CONT group, heart rate increased significantly (59±6 vs 66±7 beats/min), while stroke volume (98±12 vs 68±13 mL) and cardiac output (6±1 vs 4±1 L/min) decreased significantly (p<0.05). All subjects had similar drops on cerebral vascular function. Volume regulating hormone aldosterone increased in both groups (by 119.9% in CONT group and 112.8% in the CM group), but only in the CONT group there were a significant changes (p<0.05). Angiotensin II was significantly increased by 140.5% after 4-day HDBR in the CONT group (p<0.05), while no significant changes were observed in the CM group. These results indicated that artificial gravity with ergometric exercise successfully eliminated changes induced by simulated weightlessness in heart rate, volume regulating hormones, and cardiac pumping function and partially maintained cardiac systolic function. Hence, a daily 1h alternating +1.0 and +2.0 Gz with 40 W exercise training appear to be an effective countermeasure against cardiac deconditioning.     

WISE 2005: chronic bed rest impairs microcirculatory endothelium in women

Sedentary behavior has deleterious effects on the cardiovascular system, including reduced endothelial functions. A 2-mo bed rest study in healthy women [women international space simulation for exploration (WISE) 2005 program] presented a unique opportunity to analyze the specific effects of prolonged inactivity without other vascular risk factors on the endothelium. We investigated endothelial properties before and after 56 days of bed rest in 8 subjects who performed no exercise (control group: No-EX) and in 8 subjects who regularly performed treadmill exercise in a lower body negative pressure chamber as well as resistance exercise (countermeasure group, EX). A functional evaluation of the microcirculation in the skin was assessed with laser Doppler. We studied endothelium-dependent and -independent vasodilation using iontophoresis of acetylcholine and sodium nitroprusside, respectively. We also measured circulating endothelial cells (CECs), an index of endothelial damage. In the No-EX group, endothelium-dependent vasodilation was significantly reduced (35.4 +/- 4.8% vs. 24.1 +/- 3.8%, P < 0.05) by bed rest with a significant increase in the number of CECs (3.6 +/- 1.4 vs. 10.6 +/- 2.7 ml(-1), P < 0.05). In the EX group, endothelium-dependent vasodilation and number of CECs were preserved. Our study shows that in humans prolonged bed rest causes impairment of endothelium-dependent function at the microcirculatory level, along with an increase in circulating endothelial cells. Microcirculatory endothelial dysfunction might participate in cardiovascular deconditioning, as well as in several bed rest-induced pathologies. We therefore conclude that the endothelium should be a target for countermeasures during periods of prolonged deconditioning.     

选择性环氧合酶-2抑制剂联合奥曲肽诱导人胃癌细胞的凋亡

目的探讨选择性环氧合酶-2抑制剂NS-398与奥曲肽联合应用对人胃癌细胞株BGC-823生长、凋亡的影响。方法体外培养BGC-823细胞,分别用NS-398(100μmol/L)与奥曲肽(1μmol/L)单独及联合处理不同时间后,倒置显微镜观察细胞形态学变化;观察生长曲线的变化;流式细胞仪检测细胞凋亡率;实时定量(Real-time)PCR检测COX-2mRNA的表达;Western blot法检测Caspase-3蛋白表达。结果倒置显微镜下,对照组BGC-823细胞生长良好,药物处理后,细胞变小、变圆,悬浮,联合组细胞形态学改变显著强于单纯用药组;药物作用后,细胞生长受抑制,出现负增长,联合组作用明显强于单纯用药组;流式细胞仪检测表明联合用药组诱导BGC-823细胞的凋亡率明显高于单一用药组和对照组(P0.01);各处理组均使BGC-823细胞COX-2mRNA表达下调(P0.05);药物处理后细胞Caspase-3蛋白表达明显增加。结论 NS-398、奥曲肽联合可协同抑制BGC-823细胞生长、增殖,其机制可能与下调COX-2mRNA表达、诱导肿瘤细胞凋亡相关。     

Thin-layer cytology: identification of human papillomavirus by hybridization, capture and signal amplification assay using an alcoholic cell preservative medium

OBJECTIVE: To ensure complete reliability in the detection of hyman papillomavirus using either Specimen Transport Medium (Digene Inc., Gaithersburg, Maryland, U.S.A) or an alcoholic cell preservative. STUDY DESIGN: In order to compare both media, we adjusted the cell content of specimens and optimized the denaturation duration to avoid chemiluminescence inhibition. RESULTS: We validated this protocol in 2 groups of 90 patients, leading to agreement of 100% in both positive and negative tests. This was confirmed using linear regression curves. We demonstrated that any change in the Digene protocol, especially the use of other preservatives, should be carefully evaluated since it may interfere with DNA denaturation and hybridization and the chemiluminescence signal. The main risk was obtaining false positive responses from nonspecific DNA hybridization and false negative ones because of chemiluminescence signal inhibition. CONCLUSION: It is necessary to take into account preservative characteristics when a new protocol is under validation.     

Physical map and expression profile of genes of the telomeric class I gene region of the rat MHC

The rat is an important model for studying organ graft rejection and susceptibility to certain complex diseases. The MHC, the RT1 complex, plays a decisive role in controlling these traits. We have cloned the telomeric class I region of the RT1 complex, RT1-C/E/M, of the BN inbred rat strain in a contig of overlapping P1-derived artificial chromosome clones encompassing approximately 2 Mb, and present a physical map of this MHC region. Forty-five class I exon 4-hybridizing BAM:HI fragments were detected, including the previously known rat class I genes RT1-E, RT-BM1, RT1-N, RT1-M2, RT1-M3, and RT1-M4. Twenty-six non-class I genes known to map to the corresponding part of the human and mouse MHC were tested and could be fine mapped in the RT1-C/E/M region at orthologous position. Four previously known microsatellite markers were fine mapped in the RT1-C/E/M region and found to occur in multiple copies. In addition, a new, single-copy polymorphic microsatellite has been defined. The expression profiles of several class I genes and the 26 non-class I genes were determined in 13 different tissues and exhibited restricted patterns in most cases. The data provide further molecular information on the MHC for analyzing disease susceptibility and underline the usefulness of the rat model.     

Intensity of eccentric exercise, shift of optimum angle, and the magnitude of repeated-bout effect.

This study compared the effect of four different intensities of initial eccentric exercise (ECC1) on optimum angle shift and extent of muscle damage induced by subsequent maximal eccentric exercise. Fifty-two male students were placed into 100%, 80%, 60%, or 40% groups (n = 13 per group), performing 30 eccentric actions of the elbow flexors of 100%, 80%, 60%, or 40% of maximal isometric strength [maximal voluntary contraction (MVC)] for ECC1, followed 2-3 wk later by a similar exercise (ECC2) that used 100% MVC load. MVC at six elbow joint angles, range of motion, upper arm circumference, serum creatine kinase activity, myoglobin concentration, and muscle soreness were measured before and for 5 days following ECC1 and ECC2. A rightward shift of optimum angle following ECC1 was significantly (P < 0.05) greater for the 100% and 80% than for the 60% and 40% groups, and it decreased significantly (P < 0.05) from immediately to 5 days postexercise. By the time ECC2 was performed, only the 100% group kept a significant shift (4 degrees). Changes in most of the criterion measures following ECC1 were significantly greater for the 100% and 80% groups compared with the 60% and 40% groups. Changes in the criterion measures following ECC2 were significantly (P < 0.05) greater for the 40% group compared with other groups. Although the magnitude of repeated bout effect following ECC2 was significantly (P < 0.05) smaller for the 40% and 60% groups, all groups showed significantly (P < 0.05) reduced changes in criterion measures following ECC2 compared with the ECC1 100% bout. We conclude that the repeated-bout effect was not dependent on the shift of optimum angle.     

Influence of hyperoxia on skin vasomotor control in normothermic and heat-stressed humans.

Hyperoxia induces skin vasoconstriction in humans, but the mechanism is still unclear. In the present study we examined whether the vasoconstrictor response to hyperoxia is through activated adrenergic function (protocol 1) or through inhibitory effects on nitric oxide synthase (NOS) and/or cyclooxygenase (COX) (protocol 2). We also tested whether any such vasoconstrictor effect is altered by body heating. In protocol 1 (n = 11 male subjects), release of norepinephrine from adrenergic terminals in the forearm skin was blocked locally by iontophoresis of bretylium (BT). In protocol 2, the NOS inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME) and the nonselective COX antagonist ketorolac (Keto) were separately administered by intradermal microdialysis in 11 male subjects. In the two protocols, subjects breathed 21% (room air) or 100% O(2) in both normothermia and hyperthermia. Skin blood flow (SkBF) was monitored by laser-Doppler flowmetry. Cutaneous vascular conductance (CVC) was calculated as the ratio of SkBF to blood pressure measured by Finapres. In protocol 1, breathing 100% O(2) decreased (P < 0.05) CVC at the BT-treated and at untreated sites from the levels of CVC during 21% O(2) breathing both in normothermia and hyperthermia. In protocol 2, the administration of l-NAME inhibited (P < 0.05) the reduction of CVC during 100% O(2) breathing in both thermal conditions. The administration of Keto inhibited (P < 0.05) the reduction of CVC during 100% O(2) breathing in hyperthermia but not in normothermia. These results suggest that skin vasoconstriction with hyperoxia is partly due to the decreased activity of functional NOS in normothermia and hyperthermia. We found no significant role for adrenergic mechanisms in hyperoxic vasoconstriction. Decreased production of vasodilator prostaglandins may play a role in hyperoxia-induced cutaneous vasoconstriction in heat-stressed humans.     

Elevated urinary excretion of immunoglobulins in nonproteinuric patients with type 1 diabetes

Increased albuminuria is a hallmark of early diabetic nephropathy, whereas the role of immunoglobulins (Igs), such as IgG (its 1-4 subtypes), IgA, and IgM, different in charge and size, has not been examined in early nephropathy in the past due to lack of a sensitive and reliable method. Our study group consisted of subjects with type 1 diabetes (T1D) and normoalbuminuria (n = 78), microalbuminuria (n = 78), and of 75 healthy subjects (HS). A Luminex-based immunoassay (1,000 time more sensitive than nephelometry-based method) was validated for the urine matrix and used for the measurements of IgG1-4, IgA, and IgM in our study groups. The Luminex-based assay detected Igs in 87% of HS subjects and in 100% of T1D subjects. Recovery of known amounts of Igs added to urine was 92-118%. In the normoalbuminuria group, urinary concentrations of albumin, IgG2, IgA, and IgM were significantly higher than in HS, whereas in the microalbuminuria, further elevation of IgG2, IgG4, and IgA was the most pronounced. In all three groups, fractional excretion of Igs was at least 100 times lower than that of albumin. Fractional excretion of IgG2 was the highest among all Igs. We validated a sensitive method for measuring Igs in urine using Luminex. We found that elevated concentrations of Igs, particularly in IgG2 and IgA, is present in subjects with T1D and no proteinuria. Elevation of those particular Ig subtypes suggests a contribution of novel mechanisms in early diabetic nephropathy, different from charge and size barrier impairment.     

Effect of low frequency modulated microwave exposure on human EEG: individual sensitivity

The aim of this study was to evaluate the effect of modulated microwave exposure on human EEG of individual subjects. The experiments were carried out on four different groups of healthy volunteers. The 450 MHz microwave radiation modulated at 7 Hz (first group, 19 subjects), 14 and 21 Hz (second group, 13 subjects), 40 and 70 Hz (third group, 15 subjects), 217 and 1000 Hz (fourth group, 19 subjects) frequencies was applied. The field power density at the scalp was 0.16 mW/cm(2). The calculated spatial peak SAR averaged over 1 g was 0.303 W/kg. Ten cycles of the exposure (1 min off and 1 min on) at fixed modulation frequencies were applied. All subjects completed the experimental protocols with exposure and sham. The exposed and sham-exposed subjects were randomly assigned. A computer also randomly assigned the succession of modulation frequencies. Our results showed that microwave exposure increased the EEG energy. Relative changes in the EEG beta1 power in P3-P4 channels were selected for evaluation of individual sensitivity. The rate of subjects significantly affected is similar in all groups except for the 1000 Hz group: in first group 3 subjects (16%) at 7 Hz modulation; in second group 4 subjects (31%) at 14 Hz modulation and 3 subjects (23%) at 21 Hz modulation; in third group 3 subjects (20%) at 40 Hz and 2 subjects (13%) at 70 Hz modulation; in fourth group 3 subjects (16%) at 217 Hz and 0 subjects at 1000 Hz modulation frequency.