Rest-Activity Rhythm Differences in Acute Rehabilitation Between Poststroke Patients and Non-Brain Disease Controls: Comparative Study.

BACKGROUND: Circadian rhythm disruptions are a common concern for poststroke patients undergoing rehabilitation and might negatively impact their functional outcomes. OBJECTIVE: Our research aimed to uncover unique patterns and disruptions specific to poststroke rehabilitation patients and identify potential differences in specific rest-activity rhythm indicators when compared to inpatient controls with non-brain-related lesions, such as patients with spinal cord injuries. METHODS: We obtained a 7-day recording with a wearable actigraphy device from 25 poststroke patients (n=9, 36% women; median age 56, IQR 46-71) and 25 age- and gender-matched inpatient control participants (n=15, 60% women; median age 57, IQR 46.5-68.5). To assess circadian rhythm, we used a nonparametric method to calculate key rest-activity rhythm indicators-relative amplitude, interdaily stability, and intradaily variability. Relative amplitude, quantifying rest-activity rhythm amplitude while considering daily variations and unbalanced amplitudes, was calculated as the ratio of the difference between the most active 10 continuous hours and the least active 5 continuous hours to the sum of these 10 and 5 continuous hours. We also examined the clinical correlations between rest-activity rhythm indicators and delirium screening tools, such as the 4 A's Test and the Barthel Index, which assess delirium and activities of daily living. RESULTS: Patients who had a stroke had higher least active 5-hour values compared to the control group (median 4.29, IQR 2.88-6.49 vs median 1.84, IQR 0.67-4.34; P=.008). The most active 10-hour values showed no significant differences between the groups (stroke group: median 38.92, IQR 14.60-40.87; control group: median 31.18, IQR 18.02-46.84; P=.93). The stroke group presented a lower relative amplitude compared to the control group (median 0.74, IQR 0.57-0.85 vs median 0.88, IQR 0.71-0.96; P=.009). Further analysis revealed no significant differences in other rest-activity rhythm metrics between the two groups. Among the patients who had a stroke, a negative correlation was observed between the 4 A's Test scores and relative amplitude (ρ=-0.41; P=.045). Across all participants, positive correlations emerged between the Barthel Index scores and both interdaily stability (ρ=0.34; P=.02) and the most active 10-hour value (ρ=0.42; P=.002). CONCLUSIONS: This study highlights the relevance of circadian rhythm disruptions in poststroke rehabilitation and provides insights into potential diagnostic and prognostic implications for rest-activity rhythm indicators as digital biomarkers.

Curbing COVID-19 progression and mortality with traditional Chinese medicine among hospitalized patients with COVID-19: A propensity score-matched analysis.

BACKGROUND: Viral- and host-targeted traditional Chinese medicine (TCM) formulae NRICM101 and NRICM102 were administered to hospitalized patients with COVID-19 during the mid-2021 outbreak in Taiwan. We report the outcomes by measuring the risks of intubation or admission to intensive care unit (ICU) for patients requiring no oxygen support, and death for those requiring oxygen therapy. METHODS: This multicenter retrospective study retrieved data of 840 patients admitted to 9 hospitals between May 1 and July 26, 2021. After propensity score matching, 302 patients (151 received NRICM101 and 151 did not) and 246 patients (123 received NRICM102 and 123 did not) were included in the analysis to assess relative risks. RESULTS: During the 30-day observation period, no endpoint occurred in the patients receiving NRICM101 plus usual care while 14 (9.27%) in the group receiving only usual care were intubated or admitted to ICU. The numbers of deceased patients were 7 (5.69%) in the group receiving NRICM102 plus usual care and 27 (21.95%) in the usual care group. No patients receiving NRICM101 transitioned to a more severe status; NRICM102 users were 74.07% less likely to die than non-users (relative risk= 25.93%, 95% confidence interval 11.73%-57.29%). CONCLUSION: NRICM101 and NRICM102 were significantly associated with a lower risk of intubation/ICU admission or death among patients with mild-to-severe COVID-19. This study provides real-world evidence of adopting broad-spectrum oral therapeutics and shortening the gap between outbreak and effective response. It offers a new vision in our preparation for future pandemics.

Integrated Omics Strategy Reveals Cyclic Lipopeptides Empedopeptins from Massilia sp. YMA4 and Their Biosynthetic Pathway.

Empedopeptins-eight amino acid cyclic lipopeptides-are calcium-dependent antibiotics that act against Gram-positive bacteria such as Staphylococcus aureus by inhibiting cell wall biosynthesis. However, to date, the biosynthetic mechanism of the empedopeptins has not been well identified. Through comparative genomics and metabolomics analysis, we identified empedopeptin and its new analogs from a marine bacterium, Massilia sp. YMA4. We then unveiled the empedopeptin biosynthetic gene cluster. The core nonribosomal peptide gene null-mutant strains (ΔempC, ΔempD, and ΔempE) could not produce empedopeptin, while dioxygenase gene null-mutant strains (ΔempA and ΔempB) produced several unique empedopeptin analogs. However, the antibiotic activity of ΔempA and ΔempB was significantly reduced compared with the wild-type, demonstrating that the hydroxylated amino acid residues of empedopeptin and its analogs are important to their antibiotic activity. Furthermore, we found seven bacterial strains that could produce empedopeptin-like cyclic lipopeptides using a genome mining approach. In summary, this study demonstrated that an integrated omics strategy can facilitate the discovery of potential bioactive metabolites from microbial sources without further isolation and purification.

Differences in the skin-surface laser Doppler signals between polycystic ovary syndrome and normal subjects.

BACKGROUND: Women with PCOS may present abnormal hemodynamic alterations and thus may develop vascular damage. This study performed LDF measurements on the skin surface around the leg to verify if beat-to-beat waveform and spectral analysis can help to discriminate the MBF characteristics between PCOS and healthy subjects. METHODS: ECG and LDF signals were obtained noninvasively in PCOS (n = 16) and control (n = 8) subjects. Beat-to-beat waveform and spectral analysis was performed on the LDF signals to obtain the AD, FDT, FRT, and REC of five frequency bands. RESULTS: FRT was significantly larger, AD was significantly smaller, REC of the myogenic-related band was significantly smaller and REC of the heartbeat-related band was significantly larger in the PCOS than in the control subjects. CONCLUSION: This study is the first to reveal that time-domain waveform and spectral analysis performed on skin-surface LDF signals can be used to discriminate the differences in the MBF perfusion condition and the microcirculatory regulatory activities at local vascular beds between PCOS and healthy subjects. These findings may aid the noninvasive early detection of PCOS-induced vascular damage.

Tomographic diffractive microscopy of living cells based on a common-path configuration.

We demonstrate a common-path tomographic diffractive microscopy technique for three-dimensional (3D) refractive-index (RI) imaging of unstained living cells. A diffraction grating is utilized to generate a reference beam that traverses a blank region of the sample in a common-path off-axis interferometry setup. Single-shot phase images captured at multiple illumination angles are used for 3D RI reconstruction based on optical diffraction tomography. The common-path configuration shows lower temporal phase fluctuations and better RI resolution than a Mach-Zehnder configuration. 3D subcellular RI distributions of live HeLa cells are quantified.

Complexity analysis of the microcirculatory-blood-flow response following acupuncture stimulation.

Beat-to-beat cardiovascular variability analysis provides important information on the circulatory regulatory activities. Changes in the arterial pulse transmission or the opening condition of arteriolar openings might change the fluctuation pattern of the MBF supply, and thus change the complexity property therein. We performed complexity analysis of beat-to-beat laser Doppler flowmetry (LDF) signals to study the microcirculatory-blood-flow (MBF) response at the needled site (Hegu acupoint) following acupuncture stimulation (AS). LDF signals were measured in male healthy volunteers (n=29). Each experiment involved recording a 20-minute baseline-data sequence and two sets of effects data recorded 0-20 and 50-70min after stopping AS. Approximate-entropy (ApEn) analysis, which quantifies the unpredictability of fluctuations in a time series, was performed on each 20-minute beat-to-beat LDF data sequence. The present findings indicate that AS can not only improve the local blood supply but may also increase ApEn values and decrease MBF variability parameters. This was the first attempt to apply complexity analysis to LDF signals in order to elucidate microcirculatory responses following AS. The observed results are probably attributable to the contradictory effects on the MBF supply induced by AS, which might interfere with the microcirculatory regulatory activities so as to increase the complexity of LDF signals. The present findings could help to identify the mechanism underlying the effects of AS, might aid the development of an index for monitoring the induced microcirculatory regulatory responses, and thus provide an evidence-based connection between AS and modern physiology.

Metabolomic Analysis Demonstrates the Impacts of Polyketide Synthases PKS14 and PKS15 on the Production of Beauvericins, Bassianolide, Enniatin A, and Ferricrocin in Entomopathogen Beauveria bassiana.

Beauveria bassiana is a globally distributed entomopathogenic fungus that produces various secondary metabolites to support its pathogenesis in insects. Two polyketide synthase genes, pks14 and pks15, are highly conserved in entomopathogenic fungi and are important for insect virulence. However, understanding of their mechanisms in insect pathogenicity is still limited. Here, we overexpressed these two genes in B. bassiana and compared the metabolite profiles of pks14 and pks15 overexpression strains to those of their respective knockout strains in culture and in vivo using tandem liquid chromatography-mass spectrometry (LC-MS/MS) with Global Natural Products Social Molecular Networking (GNPS). The pks14 and pks15 clusters exhibited crosstalk with biosynthetic clusters encoding insect-virulent metabolites, including beauvericins, bassianolide, enniatin A, and the intracellular siderophore ferricrocin under certain conditions. These secondary metabolites were upregulated in the pks14-overexpressing strain in culture and the pks15-overexpressing strain in vivo. These data suggest that pks14 and pks15, their proteins or their cluster components might be directly or indirectly associated with key pathways in insect pathogenesis of B. bassiana, particularly those related to secondary metabolism. Information about interactions between the polyketide clusters and other biosynthetic clusters improves scientific understanding about crosstalk among biosynthetic pathways and mechanisms of pathogenesis.

Effects of acute slackline exercise on executive function in college students.

Background: Physical exercise as an intervention for improving cognitive function, especially executive function, is receiving increasing attention because it is easily accessible, cost-effective and promises many additional health-related benefits. While previous studies focused on aerobic exercise and resistance exercise, recent findings have suggested that exercise with high coordination demand elicits beneficial effects on executive function. We therefore examined the effects of an acute slackline exercise on the executive functions of young adults. Methods: In a crossover experimental design, 47 healthy participants (21 females), ranging in age from 18 to 27 years (M = 19.17, SD = 1.94) were randomly assigned to different sequences of two conditions (slackline exercise and film-watching). Before and after the 50 min intervention, a modified Simon task was used to assess participants' executive function (inhibitory control and cognitive flexibility). Results: College students showed better inhibitory control performance as indicated by shorter reaction times following acute slackline exercise than those who participated in the film-watching session. As there was no difference in accuracy between the slackline exercise and film-watching sessions, the shortened reaction time after slackline exercise provides evidence against a simple speed-accuracy trade-off. Conclusion: Compared with film-watching, acute slackline exercise provides favorable effects on executive function necessitating inhibition in young adults. These findings provide insight into exercise prescription and cognition, and further evidence for the beneficial effects of coordination exercise on executive functions.

Effect of Mo on the Mechanical and Corrosion Behaviors in Non-Equal Molar AlCrFeMnNi BCC High-Entropy Alloys.

Co-free body-centered cubic (bcc) high-entropy alloys (HEAs) are prepared, and the elevated mechanical property and corrosion property of the Al0.4CrFe1.5MnNi0.5Mox (x = 0 and 0.1) alloys are studied. The Vickers hardness (HV) of the as-homogenized state is between HV 350 and HV 400. Both alloys are provided with nano-scale NiAl-rich B2 precipitates which contribute to the strength at high-temperature. In addition, adding Mo in the present alloy strengthens by σ phase. Al0.4CrFe1.5MnNi0.5Mo0.1 exhibited outstanding tensile properties, with a yield strength of 413 MPa and ultimate tensile strength of 430 MPa in the elevated tensile test at 600 °C, which is better than that of Al0.4CrFe1.5MnNi0.5 alloy. Through potentiodynamic polarization testing in 0.5 M H2SO4 solution and electrochemical impedance spectroscopy (EIS), it is shown that adding Mo can effectively reduce the corrosion current density and improve the impedance of passive film, since the passivation layer is formed and stable.

Integrated therapeutic plasma exchange and traditional Chinese medicine treatment in a patient with severe COVID-19: A case report.

This report presents the case of a 59-year-old man with severe COVID-19 that gradually progressed to cytokine release syndrome and then acute respiratory distress syndrome; he was successfully treated via integration of therapeutic plasma exchange and traditional Chinese medicine. The patient initially presented with a sore throat, severe muscle aches, productive cough and fever. On the worsening of symptoms, remdesivir was administered. However, as the symptoms continued to worsen and a cytokine release syndrome was suspected, oxygen was provided through a high-flow nasal cannula (50 L/min) and therapeutic plasma exchange was performed to prevent worsening of the acute respiratory distress syndrome. On the same day, a course of traditional Chinese medicine was introduced in consultation with the infectious house staff. The patient's symptoms gradually improved; the levels of C-reactive protein and D-dimers reduced, and the patient was weaned to a simple oxygen mask and eventually to room air. This is the first reported case of the integration of these treatments. Together, they prevented the patient from requiring intubation, played a role in cytokine management, and also improved the clinical symptoms, including productive purulent sputum, cough, frequent stool passage and intermittent fever, with no adverse effects. As a result, the patient was discharged within two weeks of the integration of these treatments. Therefore, the integration of therapeutic plasma exchange and traditional Chinese medicine is an effective therapy for patients with severe COVID-19.

Electrochemical biosensor with electrokinetics-assisted molecular trapping for enhancing C-reactive protein detection.

C-Reactive protein (CRP) is an essential biomarker relevant to various disease prognoses. Current biosensors require a significant amount of time for detecting CRP. To address this issue, this work proposes electrokinetic flow-assisted molecule trapping integrated with an impedance biosensor, where a driving signal in terms of a gated sine wave is provided to circularly arranged electrodes which detect proteins. To verify the biosensor's efficacy, protein aggregation on the electrode surface was evaluated through a fluorescence analysis and measurement of the electrochemical impedance spectrum (EIS). The fluorescence analysis with avidin showed that target samples largely accumulated on the electrode surface upon provision of the driving signal. The EIS measurement of CRP accumulation on the electrode surface further confirmed a significant electrokinetic phenomenon at the electrode/electrolyte interface. Even at the low CRP concentration of 10 pg/ml, the proposed device's sensitivity and reliability were as high as 3.92 pg/ml with a signal-to noise ratio (SNR) of ≥3, respectively. In addition, the protein detection time (without considering the preparation time) was minimized to as low as 90 s with the proposed device. This device's advantage is its minimal time consumption, and simple drop-analysis process flow; hence, it was used for monitoring clinical serum samples.

Integrated omics approach to unveil antifungal bacterial polyynes as acetyl-CoA acetyltransferase inhibitors.

Bacterial polyynes are highly active natural products with a broad spectrum of antimicrobial activities. However, their detailed mechanism of action remains unclear. By integrating comparative genomics, transcriptomics, functional genetics, and metabolomics analysis, we identified a unique polyyne resistance gene, masL (encoding acetyl-CoA acetyltransferase), in the biosynthesis gene cluster of antifungal polyynes (massilin A 1, massilin B 2, collimonin C 3, and collimonin D 4) of Massilia sp. YMA4. Crystallographic analysis indicated that bacterial polyynes serve as covalent inhibitors of acetyl-CoA acetyltransferase. Moreover, we confirmed that the bacterial polyynes disrupted cell membrane integrity and inhibited the cell viability of Candida albicans by targeting ERG10, the homolog of MasL. Thus, this study demonstrated that acetyl-CoA acetyltransferase is a potential target for developing antifungal agents.

Acupuncture stimulation causes bilaterally different microcirculatory effects in stroke patients.

The aim of this study was to determine the effects of acupuncture stimulation (AS) in stroke patients by analyzing the pulsatile waveform and frequency content of skin blood-flow signals recorded simultaneously on the bilateral skin surface of the head. Laser Doppler flowmetry (LDF) signals were obtained in 18 stroke patients. Each assessment involved a 20-min baseline recording, a 20-min AS, and a further 20-min recording. Significant bilateral differences in LDF parameters were noted following AS, with an increased pulsatile component of the microcirculatory blood flow (MBF), decreased blood-flow resistance, and decreased MBF variability in the vascular beds on the stroke-affected side. Spectral analysis revealed that the vasodilation on the stroke-affected side could be partly attributed to decreased sympathetic neural activity. This is the first study to demonstrate the feasibility of evaluating the cerebral MBF conditions induced by AS in stroke patients by noninvasive LDF measurement. The present skull-intact measurement setup could aid the development of noninvasive detection techniques for determining bilateral differences in the cerebral MBF, and could thus become useful for the efficacy evaluation of treatment techniques for stroke. It might also promote understanding of the mechanisms underlying the responses and possible treatment efficacy of AS as applied to stroke patients.

Assessing the effects of acupuncture by comparing needling the hegu acupoint and needling nearby nonacupoints by spectral analysis of microcirculatory laser Doppler signals.

We aimed to assess the effects of acupuncture by analyzing the frequency content of skin blood-flow signals simultaneously recorded at the Hegu acupoint and two nearby nonacupoints following acupuncture stimulation (AS). Laser Doppler flowmetry (LDF) signals were measured in male healthy volunteers in two groups of experiments: needling the Hegu acupoint (n = 13) and needling a nearby nonacupoint (control experiment; n = 10). Each experiment involved recording a 20 min baseline-data sequence and two sets of effects data recorded 0-20 and 50-70 min after stopping AS. Wavelet transform with Morlet mother wavelet was applied to the measured LDF signals. Needling the Hegu acupoint significantly increased the blood flow, significantly decreased the relative energy contribution at 0.02-0.06 Hz and significantly increased the relative energy contribution at 0.4-1.6 Hz at Hegu, but induced no significant changes at the nonacupoints. Also, needling a nearby nonacupoint had no effect in any band at any site. This is the first time that spectral analysis has been used to investigate the microcirculatory blood-flow responses induced by AS, and has revealed possible differences in sympathetic nerve activities between needling the Hegu acupoint and its nearby nonacupoint. One possible weakness of the present design is that different De-Qi feelings following AS could lead to nonblind experimental setup, which may bias the comparison between needling Hegu and its nearby nonacupoint. Our results suggest that the described noninvasive method can be used to evaluate sympathetic control of peripheral vascular activity, which might be useful for studying the therapeutic effects of AS.

Assessing the microcirculatory response following oral administration of Liuwei Dihuang formula by spectral analysis of skin-surface laser Doppler signals.

OBJECTIVE: This study aimed to assess the skin-surface microcirculatory effects of oral administration of Liuwei Dihuang (LW) formula by analyzing the frequency content of laser-Doppler skin blood-flow signals at important acupoints. METHODS: Laser-Doppler signals were measured in male healthy volunteers in two groups of experiments: the LW experiment (n=42; aged (27.8±3.8) years) and the control experiment (n=28; aged (27.3±3.4) years). Each experiment involved a 20-minute baseline-data sequence and three following sets of effects data: recorded on the same day after oral administration of 250 mL water (28 degrees centigrade) accompanied with 5 g of LW formula (herbal extract granules), and recorded on the second day after taking other two doses of LW formula. RESULTS: During the second day, the increases in the mean and pulsatile components of the flux signal were the most prominent, and the relative energy contribution at 0.02 to 0.06 Hz was significantly decreased at Taixi (KI3). There were no any other significant changes in these parameters at other measurement sites. CONCLUSION: The redistribution of skin-surface microcirculatory blood flow following oral LW administration observed here can be attributed to different changes in sympathetic neural activities and thus the different perfusion resistance through the arteriolar openings of the peripheral vascular beds at different measurement sites. The developed noninvasive and real-time monitoring technique could form part of an evidence-based method for studying the physiological effects and the underlying mechanisms of traditional Chinese medicine herbs.

Exploring Shank Circumference by Stretching after Training among Volleyball Players.

This preliminary study examined the effects of a stretching intervention after training and its duration (15 vs. 30 min) on participants' shank circumference (SC) reduction and subjective discomfort score. Ten male volleyball players underwent a routine 3 h training. A two-way analysis of variance revealed that the stretching intervention had significant effects on SC reduction (p < 0.01) and subjective discomfort scores (p < 0.001). Stretching after training could help eliminate shank strain, and a slighter discomfort in shanks when stretching was also seen (score, 20.1/100). An independent-samples t test revealed a significantly higher SC reduction (p < 0.01) with 30 min of stretching (5.6 mm) than with 15 min of stretching (2.7 mm); both stretching durations reduced SC significantly more than the no-stretching condition did. The findings of this study can serve as a reference for volleyball players to alleviate shank strain after daily routine training.

Spectral analysis of the microcirculatory laser Doppler signal at the Hoku acupuncture point.

We aimed to characterize the frequency spectra of skin blood flow signals recorded at Hoku, an important acupuncture point (acupoint) in oriental medicine. Electrocardiogram (ECG) and laser Doppler flowmetry signals were measured simultaneously in 31 trials on seven volunteers aged 21-27 years. A four-level Haar wavelet transform was applied to the measured 20 min laser Doppler flowmetry (LDF) signals, and periodic oscillations with five characteristic frequency peaks were obtained within the following frequency bands: 0.0095-0.021 Hz, 0.021-0.052 Hz, 0.052-0.145 Hz, 0.145-0.6 Hz, and 0.6-1.6 Hz (defined as FR1-FR5), respectively. The relative energy contribution in FR3 was significantly larger at Hoku than at the two non-acupoints. Linear regression analysis revealed that the relative energy contribution in FR3 at Hoku significantly increased with the pulse pressure (R(2) = 0.48; P < 0.01 by F-test). Spectral analysis of the flux signal revealed that one of the major microcirculatory differences between acupoints and non-acupoints was in the different myogenic responses of their vascular beds. This information may aid the development of a method for the non-invasive study of the microcirculatory characteristics of the acupoint.

Effects of acupuncture at the Hoku acupoint on the pulsatile laser Doppler signal at the heartbeat frequency.

We aimed to assess the effects of acupuncture by analyzing the alternating current (AC) component of skin blood-flow signals (around the heartbeat frequency) simultaneously recorded at the Hoku acupoint, which is an important acupoint in oriental medicine, and two nearby non-acupoints following acupuncture stimulation (AS). Laser Doppler flowmetry signals were measured in 28 experiments on nine volunteers. Each experiment involved the recording of a 20-min control-data sequence and two sets of effects data recorded 0-20 min and 50-70 min after the AS had been stopped. The direct current (DC) and AC components (DCflux and ACflux, respectively), pulse width (PW), and foot delay time (FDT) of the flux signal were calculated. The DCflux, ACflux, PW, and FDT were all significantly increased only at Hoku following AS. Regression analysis between the DCflux and ACflux revealed that the slope was largest (>1) at Hoku among the measurement sites. Our results indicated that both the DCflux and ACflux in the microcirculatory perfusion were increased by stimulation at the Hoku acupoint, with the change being greatest for the latter. Parameters calculated from the pulsatile flux waveform, such as the PW and FDT, could contribute to noninvasive evaluations of the sympathetic neural activities and of the improvement in perfusion following AS.

Prescription of Chinese herbal products is associated with a decreased risk of uterine fibroids: A population-based cohort study.

The finding of a decrease in subsequent fibroid-related operation following the use of Chinese herbal products (CHPs) has led to speculation that CHPs might play a role in uterine fibroids prevention.This study provides an overview of uterine fibroids incidence, comparing CHP users with those who do not use CHPs, referred to as non-CHP users. The results can provide information to clinicians for counseling women about the preventive use of CHPs.A total of 52,151 women (20-45 years of age) were recruited from a nationwide 1-million-person representative sample of those covered by National Health Insurance in Taiwan and were followed from 2000 to 2013. Exact matching was performed for comparative analysis. The age-specific hazard ratios (HRs) of uterine fibroids in relation to either CHP or the phytoestrogen use were calculated with multivariate Cox proportional hazard regression.More than 71% of patients had used a CHP at some point previously. The overall incidence density rate of uterine fibroids for non-CHP users was estimated at 27.5 per 1000 patient-years. The corresponding values for CHP and the phytoestrogen users were lower than those of the non-CHP group (CHP group = 15.5; the phytoestrogen group = 12.5 per 1000 patient-years). The covariate adjusted HRs for uterine fibroid were 0.73 (95% confidence interval [CI] 0.63-0.85) and 0.65 (95% CI 0.52-0.82) in women using CHPs and the phytoestrogen, respectively.CHPs seem to contribute to a decreased risk in developing uterine fibroids. Although the mechanism of action of these products is unclear, their use as a preventive agent for uterine fibroids might be taken into consideration.

Microcirculatory effect of different skin contacting pressures around the blood pressure.

We used laser Doppler flowmetry (LDF) and spectrum analysis to investigate the microcirculatory responses to pressure stimulation (PS) of the skin surface. A control group without PS applied, and four groups with different PS (20, 60, 100 and 160 mmHg in groups PS(20), PS(60), PS(100) and PS(160), respectively) were formed from seven volunteers. Each experiment involved recording a 20 min baseline and two effect data recorded at 0-20 and 50-70 min after stopping PS. The relative energy contribution (REC) in five frequency bands revealed by Morlet-wavelet transformation was calculated. At the pressed site, the dc component of the flux signal in the second effect increased significantly only in group PS(60) compared with the control values. The REC was significantly increased in a myogenic-related band in groups PS(60), PS(100) and PS(160), and was significantly decreased in a nerve-related band only in group PS(160). Different PS magnitudes compress vessels to different extents. The proposed vessel-pressing model-which is supported by the results of spectral analysis of flux signals-might help to elucidate the underlying mechanism. The study results indicate that an improved perfusion was sustained for the longest time when applying 60 mmHg PS. This might aid the development of techniques for improving skin microcirculatory perfusion.