Palm-Sized Wireless Transient Elastography System with Real-Time B-Mode Ultrasound Imaging Guidance: Toward Point-of-Care Liver Fibrosis Assessment

Transient elastography (TE), recommended by the WHO, is an established method for characterizing liver fibrosis via liver stiffness measurement (LSM). However, technical barriers remain towards point-of-care application, as conventional TE requires wired connections, possesses a bulky size, and lacks adequate imaging guidance for precise liver localization. In this work, we report the design, phantom validation, and clinical evaluation of a palm-sized TE system that enables simultaneous B-mode imaging and LSM. The performance of this system was validated experimentally using tissue-equivalent reference phantoms (1.45-75 kPa). Comparative studies against other liver elastography techniques, including conventional TE and two-dimensional shear wave elastography (2D-SWE), were performed to evaluate its reliability and validity in adults with various chronic liver diseases. Intra- and inter-operator reliability of LSM were established by an elastography expert and a novice. A good agreement was observed between the Young's modulus reported by the phantom manufacturer and this system (bias: 1.1-8.6%). Among 121 patients, liver stiffness measured by this system and conventional TE were highly correlated (r = 0.975) and strongly agreed with each other (mean difference: -0.77 kPa). Inter-correlation of this system with conventional TE and 2D-SWE was observed. Excellent-to-good operator reliability was demonstrated in 60 patients (ICCs: 0.824-0.913). We demonstrated the feasibility of employing a fully integrated phased array probe for reliable and valid LSM, guided by real-time B-mode imaging of liver anatomy. This system represents the first technical advancement toward point-of-care liver fibrosis assessment. Its small footprint, along with B-mode guidance capability, improves examination efficiency and scales up screening for liver fibrosis.

Electroacupuncture Stimulation Alleviates Inflammatory Pain in Male Rats by Suppressing Oxidative Stress

In the present study, we focused on whether the analgesic effect of Electroacupuncture (EA) is related to the regulation of oxidative stress. We established a chronic inflammatory pain model in male rats by a single injection of complete Freund's adjuvant (CFA) and then treated the animals with daily EA stimulation at the site of "zusanli". The analgesic effect of EA was evaluated by measuring the paw withdrawal threshold (PWT) when rats received mechanical and thermal pain stimulation. The levels of inflammation-related molecules and oxidative stress-related markers in the spinal cord were measured by western blotting or ELISA kits. EA stimulation and antioxidants effectively increased the PWT in CFA rats. Co-treatment of CFA rats with the ROS donor t-butyl hydroperoxide (t-BOOH) further decreased the PWT and weakened the analgesic effect of EA. EA treatment inhibited inflammation and oxidative stress, as shown by decreased levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1beta), IL-6, and MDA and increased activity of SOD and catalase. Moreover, EA reduced the expression of p-p38, p-ERK, and p-p65 and simultaneously downregulated the expression of TRPV1 and TRPV4 in CFA rats. In an in vitro study, direct stimulation with t-BOOH to the C6 cells increased the production of TNF-alpha, IL-1beta, IL-6, activated p38, ERK, and p65 and up-regulated the expression of TRPV1 and TRPV4, and these effects could be prevented by the ROS scavenger PBN. Taken together, our data indicate that the inhibition of oxidative stress and the generation of ROS contribute to the analgesic effect of EA in male CFA rats.

How Paretic and Non-Paretic Ankle Muscles Contract during Walking in Stroke Survivors: New Insight Using Novel Wearable Ultrasound Imaging and Sensing Technology

Abnormal muscle tone and muscle weakness are related to gait asymmetry in stroke survivors. However, the internal muscle morphological changes that occur during walking remain unclear. To address this issue, this study investigated the muscle activity of the tibialis anterior (TA) and medial gastrocnemius (MG) of both the paretic and non-paretic sides during walking in nine stroke survivors, by simultaneously capturing electromyography (EMG), mechanomyography (MMG), and ultrasound images, and using a validated novel wearable ultrasound imaging and sensing system. Statistical analysis was performed to examine the test−retest reliability of the collected data, and both the main and interaction effects of each “side” (paretic vs. non-paretic) and “gait” factors, in stroke survivors. This study observed significantly good test−retest reliability in the collected data (0.794 ≤ ICC ≤ 0.985), and significant differences existed in both the side and gait factors of the average TA muscle thickness from ultrasound images, and in the gait factors of TA and MG muscle’s MMG and EMG signals (p < 0.05). The muscle morphological characteristics also appeared to be different between the paretic and non-paretic sides on ultrasound images. This study uncovered significantly different internal muscle contraction patterns between paretic and non-paretic sides during walking for TA (7.2% ± 1.6%) and MG (5.3% ± 4.9%) muscles in stroke survivors.

Real-Time Visual Biofeedback via Wearable Ultrasound Imaging Can Enhance the Muscle Contraction Training Outcome of Young Adults

ABSTRACT

Huang, Z-H, Ma, CZ-H, Wang, L-K, Wang, X-Y, Fu, S-N, and Zheng, Y-P. Real-time visual biofeedback via wearable ultrasound imaging can enhance the muscle contraction training outcome of young adults. J Strength Cond Res 36(4): 941-947, 2022-Real-time ultrasound imaging (RUSI) can serve as visual biofeedback to train deep muscle contraction in clinical rehabilitative settings. However, its effectiveness in resistance training in sports/fitness fields remains unexplored. This article introduced a newly developed wearable RUSI system that provided visual biofeedback of muscle thickening and movement and reported its effectiveness in improving the training outcomes of muscle thickness change (%) during dynamic contraction. Twenty-five healthy young men participated and performed pec fly exercise both with and without RUSI biofeedback. Statistical analysis was conducted to examine the reliability of the measurements and the immediate effects of (a) RUSI biofeedback of muscle contraction and (b) training intensity (50 vs. 80% of 1-repetition maximum [1RM]) on the pectoralis major (PMaj) thickness change measured by ultrasound images. In addition to significantly high inter-contraction reliability (ICC3,1 > 0.97), we observed significantly increased PMaj thickness change for both training intensities upon receiving biofeedback in subjects, compared with without biofeedback (p < 0.001). We also observed significantly larger PMaj thickness change at 80% of 1RM compared with 50% of 1RM (p = 0.023). The provision of visual biofeedback using RUSI significantly enlarged the magnitude of PMaj thickness change during pec fly exercises, potentially indicating that RUSI biofeedback could improve the ability of targeted muscle contraction of PMaj in healthy young adults. To our knowledge, this study has pioneered in applying RUSI as a form of biofeedback during weight training and observed positive effectiveness. Future iterations of the technique will benefit more subject groups, such as athletes and patients with neuromuscular disorders.

Prevalence and diagnostic yield of investigating t wave inversion in a large unselected pre-participation cohort of young Asian males

Background/Introduction

T wave inversion (TWI) is a potentially abnormal finding on pre-participation screening electrocardiography (ECG), as it may suggest an underlying cardiomyopathy that should be risk stratified appropriately to minimise the risk of sports-related sudden cardiac death. Existing international guidelines prescribe criteria for investigating TWI in athletes. However, it is not established if these criteria can be extrapolated to screening unselected individuals. There is also evidence recommending against investigating specific patterns of anterior TWI in certain subsets of athletes due to low diagnostic yield; whether these exemptions may apply to non-athletes is uncertain. Given the importance of physical activity for primary prevention of cardiovascular disease in the general population, more evidence to guide pre-participation ECG screening of unselected individuals is needed.

Purpose

Firstly, to determine the epidemiology of abnormal TWI in a large unselected pre-participation cohort of young males of predominantly Asian ethnicity. Secondly, to determine the diagnostic yield of an echocardiography-guided approach to investigating individuals with abnormal TWI for a cardiomyopathy.

Methods

All individuals who attended a national centre for pre-enlistment cardiac screening over 39 months from 2017 were examined. Demographic data, anthropometric data and standardised physical fitness test scores were collected. Resting 12-lead ECG was performed for all individuals. Those with abnormal TWI, defined as a negatively deflected T wave of at least 0.1 mV amplitude in two contiguous leads, were referred to tertiary centres for echocardiography.

Results

69,714 consecutive males of mean age 17.9±1.1 years were screened. 562 individuals (0.8%) displayed abnormal TWI. Better aerobic fitness, but not muscular strength, was associated with a higher prevalence of abnormal TWI in general and specifically in the anterior territory, although not beyond leads V1-V2. Aerobic fitness had no association with abnormal TWI in the inferior territory or lateral territory. Of those with abnormal TWI, 12 individuals (2.1%) were newly diagnosed with a cardiomyopathy. Significant factors associated with a cardiomyopathy diagnosis were abnormal TWI in the lateral territory, abnormal TWI in the anterior territory beyond lead V2, deeper maximum TWI depth, presence of hypertension and higher body mass index. No individual presenting with TWI restricted to solely leads V1-V2 and/or two inferior leads without abnormal TWI in other contiguous leads was diagnosed with a cardiomyopathy.

Conclusion

Investigating abnormal TWI in an unselected pre-participation cohort of young Asian males had a significant yield, particularly in individuals manifesting abnormal TWI in the lateral territory and the anterior territory beyond lead V2. The ECG finding of anterior TWI in an unselected population may not be as benign as that in athletic populations.

Funding Acknowledgement

Type of funding sources: None. Abnormal TWI: Prevalence and Yield

The crystal structure of 5-nitropicolinic acid monohydrate, C6H6N2O5

C6H6N2O5, monoclinic, C2/c (no. 15), a = 13.1766(11) Å, b = 5.1019(4) Å, c = 22.602(2) Å, β = 91.081(3)°, V = 1519.2(2) Å3, Z = 8, R gt(F) = 0.0334, wR ref(F 2) = 0.0961, T = 150(2) K.

[Color stability of computer aided design and computer aided manufacture composite ceramic/resin cements after accelerated ageing]

Objective: To investigate the color stability of computer aided design and computer aided manufacture (CAD/CAM) composite ceramic/resin cements after accelerated ageing. Methods: Twelve groups (ten samples each group) were used as experimental groups, which were composed of CAD/CAM composite ceramic of three kinds of thickness (0.50, 0.75, 1.00 mm) (Lava Ultimate) associated with resin cements (Variolink N) of four colors (A1, A3, T, BL1). Another three groups of CAD/CAM composite ceramic/resin cements of three different kinds of thickness (0.50, 0.75, 1.00 mm) were used as control groups (ten samples each group). All samples were put into the xenon lamp ageing instrument to implement accelerated ageing. Spectrophotometers were used to measure the lightness (L(*)), red green color value (a(*)) and blue yellow color value (b(*)) of all samples before and after accelerated ageing process, and the changes of color variation (ΔE) was calculated. The effect of composite ceramic thickness and resin cement color on the changes of color variation (ΔE) before and after the ageing of CAD/CAM composite ceramic/resin cement and whether there was an interaction between them were tested by two-way ANOVA. Results: Before and after accelerated ageing, the ΔE of CAD/CAM composite ceramic/resin cements were <3.3. Two-way ANOVA showed that the thickness of CAD/CAM composite ceramics had an effect on ΔE (F=27.025, P<0.001), and the color of resin cement also had an effect on ΔE (F=15.606, P<0.001), but there was no interaction between them (F=0.534, P=0.829). Conclusions: The thickness of CAD/CAM composite ceramics and the color of resin cements could both affect the color stability of composite ceramic/resin cements combination. However, the resulted color change is within the clinically acceptable range.

Towards Wearable Comprehensive Capture and Analysis of Skeletal Muscle Activity during Human Locomotion

Background: Motion capture and analyzing systems are essential for understanding locomotion. However, the existing devices are too cumbersome and can be used indoors only. A newly-developed wearable motion capture and measurement system with multiple sensors and ultrasound imaging was introduced in this study. Methods: In ten healthy participants, the changes in muscle area and activity of gastrocnemius, plantarflexion and dorsiflexion of right leg during walking were evaluated by the developed system and the Vicon system. The existence of significant changes in a gait cycle, comparison of the ankle kinetic data captured by the developed system and the Vicon system, and test-retest reliability (evaluated by the intraclass correlation coefficient, ICC) in each channel’s data captured by the developed system were examined. Results: Moderate to good test-retest reliability of various channels of the developed system (0.512 ≤ ICC ≤ 0.988, p < 0.05), significantly high correlation between the developed system and Vicon system in ankle joint angles (0.638R ≤ 0.707, p < 0.05), and significant changes in muscle activity of gastrocnemius during a gait cycle (p < 0.05) were found. Conclusion: A newly developed wearable motion capture and measurement system with ultrasound imaging that can accurately capture the motion of one leg was evaluated in this study, which paves the way towards real-time comprehensive evaluation of muscles and joint motions during different activities in both indoor and outdoor environments.

[Effects of thermal cycling on mechanical properties of resin-ceramic composites]

Objective: To investigate the influence of thermal cycling on the mechanical properties of resin-ceramic composites. Methods: The different groups of resin-ceramic composites A (Lava Ultimate, 3M ESPE, USA), B (block HC, Shofu, Japan), C (Hyramic, Upcera, China), D (Vita Enamic, Vita, German), and the feldspar ceramic E (Mark Ⅱ, Vita, German) were included in this study. The properties of these groups (with 30 samples in each group), including flexural strength, flexural modulus and Vickers hardness were tested before and after thermal cycling (0, 10 000 and 20 000 cycles, respectively). The data were statistically analyzed. Results: Before thermal cycling, the flexural strength of groups A, B and C [(166.28±13.78) MPa, (170.21±11.36) MPa and (202.04±16.55) MPa] were higher than those of groups D and E [(137.09±8.83) MPa and (119.35±5.98) MPa], and the flexural modulus [(62.39±3.40) GPa] and Vickers hardness [(406.97±14.73) HV] of E group were higher than those of other groups (P<0.05). The flexural strength, flexural modulus and Vickers hardness of groups D and E did not change after thermal cycling (all P>0.05), while those of groups A, B and C decreased (all P<0.05). Conclusion: After thermal cycling, the mechanical properties of the A, B and C groups decreased, while those of the groups D and E were stable.

Effects of tributyrin supplementation on ruminal microbial protein yield, fermentation characteristics and nutrients degradability in adult Small Tail ewes

Two trials were conducted to assess the effects of tributyrin (TB) supplementation on ruminal microbial protein yield and fermentation characteristics in adult sheep. In an in vitro trial, substrate was made to offer TB at 0, 2, 4, 6, and 8 g/kg on a dry matter (DM) basis and incubated for 48 hr. In an in vivo trial, 45 adult ewes were randomly assigned by initial body weight (55 ± 5 kg) to five treatments of nine animals over an 18-day period. Total mixed ration was made to offer TB to ewes at 0, 2, 4, 6, and 8 g/kg on a DM basis. The in vitro trial showed that TB enhanced apparent degradation of DM (p = .009), crude protein (p < .001), neutral detergent fiber (p = .007) and acid detergent fiber (p = .010) and increased methanogenesis (p < .001), respectively. The in vivo trial showed that TB decreased DM intake (p < .001) and enhanced rumen microbial N synthesis (p < .001), respectively. Both in vitro and in vivo trials showed that TB increased total volatile fatty acid concentration and enhanced fibrolytic enzyme activity. The results indicated that TB might exert positive effects on microbial protein yield and fermentation in the rumen.

Benzoxazole-Linked Ultrastable Covalent Organic Frameworks for Photocatalysis

The structural uniqueness of covalent organic frameworks (COFs) has brought these new materials great potential for advanced applications. One of the key aspects yet to be developed is how to improve the robustness of covalently linked reticular frameworks. In order to make the best use of π-conjugated structures, we develop herein a "killing two birds with one stone" strategy and construct a series of ultrastable benzoxazole-based COFs (denoted as LZU-190, LZU-191, and LZU-192) as metal-free photocatalysts. Benefiting from the formation of benzoxazole rings through reversible/irreversible cascade reactions, the synthesized COFs exhibit permanent stability in the presence of strong acid (9 M HCl), strong base (9 M NaOH), and sunlight. Meanwhile, reticulation of the benzoxazole moiety into the π-conjugated COF frameworks decreases the optical band gap and therefore increases the capability for visible-light absorption. As a result, the excellent photoactivity and unprecedented recyclability of LZU-190 (for at least 20 catalytic runs, each with a product yield of 99%) have been illustrated in the visible-light-driven oxidative hydroxylation of arylboronic acids to phenols. This contribution represents the first report on the photocatalytic application of benzoxazole-based structures, which not only sheds new light on the exploration of robust organophotocatalysts from small molecules to extended frameworks but also offers in-depth understanding of the structure-activity relationship toward practical applications of COF materials.

[Copy number variants analysis in whole-genome of patients with lipoma tethered cord syndrome]

Objective: To explore the abnormality of chromosomes of patients with lipoma tethered cord syndrome and the probable association between Copy Number Variations (CNV) and lipoma tethered cord syndrome. Methods: By using the Agilent SurePrint G3 Human CGH 8×60K Microarray Kit, we performed genome-wide screening for CNV on 11 patients with lipoma tethered cord syndrome adopted by the Neurosurgery Department of Chinese PLA General Hospital and their healthy parents from March 2015 to May 2015. We analyze CNVs got by the kit against the gene databases. Unrelated confirmed polymorphisms contained in Database of Genomic Variants (DGV) were discarded. Database of Chromosomal Imbalance and Phenotype in Humans using Ensemble Resources (DECIPHER) helps us with similarity inquiry, and UCSC Genome Browser helps in identification of non-polymorphic CNV. Biological process, cellular component and molecular function enrichment of these genes were conducted to confirm the association between the CNV and lipoma tethered cord syndrome. Results: 17 CNV were discovered by aCGH in 11 patients. Chr8: 39258894-39386158 and Chr15: 20481702-22509254 showed a high frequency of 5/11. Angelman syndrome and Prader-Wolli syndrome were found to be associated with the CNV of Chr15. Gene function enrichment analysis revealed that ADAM5P and ADAM3A contained in CNV obtained from patients with lipoma tethered cord syndrome was also associated with orofacial clefts. Conclusions: CNV in Chr8 and Chr15 of patients with lipoma tethered cord syndrome had a higher frequency than that of common human. It revealed that there is probable association between these two pieces of CNV and lipoma tethered cord syndrome. To explorer related genes or CNV, focusing on certain type of NTDs may increase the research efficiency and get more accurate results.

The effect of leflunomide on the transplanted endometriosis lesions in SD rats

OBJECTIVE

To investigate the effects of the leflunomide (LEF) on the size of the transplanted endometriosis (EMS) lesions and trans- forming growth factor (TGF) -β1gray level in SD rats.

MATERIALS AND METHODS

EMS was surgically induced in rats by autologous trans- plantation and the focal volume was also measured. The rats were divided into three groups: group A: normal SD rats, group B: rats irrigated by one ml-kg⁻¹d⁻¹ saline for three weeks, and group C: rats irrigated by 35 mg-kg⁻¹d⁻¹ LEF for three weeks. The rats were then sacrificed and measured their focal volume and TGF-β1 gray value with immunohistochemical method.

RESULTS

The sizes of the focal volume in group C were significantly reduced compared to the rats before feeding, and the volume in group C was smaller than group B after feeding and so was the TGF-β1.

CONCLUSION

LEF could be a new therapeutic drug for EMS.

Measurement of corneal tangent modulus using ultrasound indentation

Biomechanical properties are potential information for the diagnosis of corneal pathologies. An ultrasound indentation probe consisting of a load cell and a miniature ultrasound transducer as indenter was developed to detect the force-indentation relationship of the cornea. The key idea was to utilize the ultrasound transducer to compress the cornea and to ultrasonically measure the corneal deformation with the eyeball overall displacement compensated. Twelve corneal silicone phantoms were fabricated with different stiffness for the validation of measurement with reference to an extension test. In addition, fifteen fresh porcine eyes were measured by the developed system in vitro. The tangent moduli of the corneal phantoms calculated using the ultrasound indentation data agreed well with the results from the tensile test of the corresponding phantom strips (R(2)=0.96). The mean tangent moduli of the porcine corneas measured by the proposed method were 0.089±0.026MPa at intraocular pressure (IOP) of 15mmHg and 0.220±0.053MPa at IOP of 30mmHg, respectively. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) of tangent modulus were 14.4% and 0.765 at 15mmHg, and 8.6% and 0.870 at 30mmHg, respectively. The preliminary study showed that ultrasound indentation could be applied to the measurement of corneal tangent modulus with good repeatability and improved measurement accuracy compared to conventional surface displacement-based measurement method. The ultrasound indentation can be a potential tool for the corneal biomechanical properties measurement in vivo.

Determining in vivo elasticity and viscosity with dynamic Scheimpflug imaging analysis in keratoconic and healthy eyes

The paper presents a novel analysis method of corneal elasticity and viscosity based on corneal visualization Scheimpflug technology (CorVis ST) for keratoconus diagnosis. Methods for air puff force measurement and corneal imaging boundary extraction were proposed. Corneal biomechanical properties, described as tangent stiffness coefficient (STSC ) and energy absorbed area (Aabsorbed ), were assessed using the curves of the applied air puff force with corneal displacement to form a loading-unloading cycle. Twenty-five patients with keratoconus and 34 healthy control subjects, matched for intraocular pressure (IOP), were enrolled in this prospective study. The results showed that the intraclass correlation coefficients (ICC) of the STSC and Aabsorbed were 0.941 and 0.878 in Healthy group; and were 0.891 and 0.809 in Keratoconus group, respectively. Both STSC and Aabsorbed of keratoconus patients were significantly different from that of controls (both probability value P < 0.001). ROC curve analysis showed that the area under curve for STSC was 0.918 and for Aabsorbed was 0.894, which reached a good level of predictive accuracy for detecting keratoconus. Our results demonstrated that this new analysis method could be used to characterize the biomechanical properties of corneas. (a) The air puff force of CorVis ST was measured by a custom-designed force detection system. (b) Corneal displacement was extracted from CorVis ST using a proposed imaging analysis. (c) With the utilization of the air puff force and corneal dynamic displacement, an analysis method was developed to introduce new corneal biomechanical parameters - STSC and Aabsorbed .

Influence of hepatic ischemia-reperfusion on postoperative spatial cognitive function in mice

The aim of this study was to investigate the effects of partial hepatic ischemia/reperfusion (I/R) on postoperative cognitive function in mice. One hundred Kunming mice were randomized into control group (N = 20), sham group (N = 20) and I/R group (N = 60), which was equally divided into 3 subgroups according to the ischemia time (20, 30 and 40 min). Half of the mice in each group underwent a passive avoidance test on the 4th day, and the other underwent the test on the 18th day, which lasted for 6 days before euthanasia for analysis of brain pathology and immunohistochemistry for ChAT. The passive avoidance test showed that there was no significance in the incubation period and number of errors between the control and sham group, but there was a longer incubation period and more errors in the I/R group than control group; at G2, there was no significance between all groups. Hematoxylin-eosin staining of the hippocampus showed that at G1, there was no obvious change in hippocampal neurons in structure and arrangement except for IR/40 min; at G2, there was no significance between all groups. Immunohistochemistry of hippocampus for ChAT showed the following: at G1, there was no significance in average optical density of CA3 area between control and sham group, but optical density was significantly lower in I/R groups with I/R 40 min showing the lowest; at G2, there was no significance between all groups. Pentobarbital has no effect on cognitive function, but hepatic partial ischemia and reperfusion injury does and could become worse over time.

Ultrasound biomicroscopy measurement of skin thickness change induced by cosmetic treatment with ultrasound stimulation

Moisturizing creams and lotions are commonly used in daily life for beauty and treatment of different skin conditions such as dryness and wrinkling, and ultrasound stimulation has been used to enhance the delivery of ingredients into skin. However, there is a lack of convenient methods to study the effect of ultrasound stimulation on lotion absorption by skin in vivo. Ultrasound biomicroscopy was adopted as a viable tool in this study to investigate the effectiveness of ultrasound stimulation on the enhancement of lotion delivery into skin. The forearm skin of 10 male and 10 female young subjects was tested at three different sites, including two lotion treatment sites with (Ultrasound Equipment - UE ON) and without (UE OFF) ultrasound stimulation and a control site without any lotion treatment. 1 MHz ultrasound with a duty cycle of 1.7%, a spatial peak temporal peak pressure of 195 kPa and an average power of 0.43 W was used for the stimulation. The skin thickness before, immediately after (0 min), and 15 and 30 min after the treatment was measured by an ultrasound biomicroscopic system (55 MHz). It was found that the skin thickness significantly increased immediately after the lotion treatment for both UE ON (from 1.379 ± 0.187 mm to 1.466 ± 0.182 mm, p<0.001) and UE OFF (from 1.396 ± 0.193 mm to 1.430 ± 0.194 mm, p<0.001) groups. Further comparison between the two groups revealed that the skin thickness increase of UE ON group was significantly larger than that of UE OFF group (6.5 ± 2.4% vs. 2.5 ± 1.3%, p<0.001). Furthermore, it was disclosed that the enhancement of lotion delivery by ultrasound stimulation was more effective for the female subjects than the male subjects (7.6 ± 2.3% vs. 5.4 ± 2.0% immediately after treatment, p=0.017). In conclusion, this study demonstrated that ultrasound biomicroscopy was a feasible method for studying the effectiveness of lotion treatment in vivo, and ultrasound stimulation was effective to enhance the rate of lotion absorption into skin.

Application of cetyltrimethylammonium bromide bentonite-titanium dioxide photocatalysis technology for pretreatment of aging leachate

Organobentonite-photocatalysis technology was applied to pretreat aging leachate containing refractory pollutants. The organobentonite was synthesized by organic modifier cetyltrimethylammonium bromide (CTMAB) and natural bentonite. In characterization experiments, we could confirm that organic functional groups of cetyltrimethylammonium (CTMA(+)) cations were successfully loaded on the surface of bentonite. The combination of CTMAB2.5 adsorption and TiO2 photocatalysis was superior to either running separately. Furthermore, removal efficiency of simultaneously utilizing CTMAB2.5 and TiO2 was better than them in succession. The combination technology was feasible and was optimized by response surface methodology (RSM) with COD and NH3-N removal rate as the target responses. The optimal operation conditions calculated from the regression equations were CTMAB2.5 dosage of 7.5 g/L, pH at 3.5, TiO2 dosage of 1.63 g/L, and reaction time for 60.02 min, which maintained the removal of COD and NH3-N at 82% and 37%, respectively.

In vivo and ex vivo approaches to studying the biomechanical properties of healing wounds in rat skin

An evaluation of wound mechanics is crucial in reflecting the wound healing status. The present study examined the biomechanical properties of healing rat skin wounds in vivo and ex vivo. Thirty male Sprague-Dawley rats, each with a 6 mm full-thickness circular punch biopsied wound at both posterior hind limbs were used. The mechanical stiffness at both the central and margins of the wound was measured repeatedly in five rats over the same wound sites to monitor the longitudinal changes over time of before wounding, and on days 0, 3, 7, 10, 14, and 21 after wounding in vivo by using an optical coherence tomography-based air-jet indentation system. Five rats were euthanized at each time point, and the biomechanical properties of the wound tissues were assessed ex vivo using a tensiometer. At the central wound bed region, the stiffness measured by the air-jet system increased significantly from day 0 (17.2%), peaked at day 7 (208.3%), and then decreased progressively until day 21 (40.2%) as compared with baseline prewounding status. The biomechanical parameters of the skin wound samples measured by the tensiometer showed a marked reduction upon wounding, then increased with time (all p &lt; 0.05). On day 21, the ultimate tensile strength of the skin wound tissue approached 50% of the normal skin; while the stiffness of tissue recovered at a faster rate, reaching 97% of its prewounded state. Our results suggested that it took less time for healing wound tissues to recover their stiffness than their maximal strength in rat skin. The stiffness of wound tissues measured by air-jet could be an indicator for monitoring wound healing and contraction.

The thin-layer drying characteristics of sewage sludge by the appropriate foaming pretreatment

As dewatered sludge is highly viscous and sticky, the combination of foaming pretreatment and drying process seems to be an alternative method to improve the drying performance of dewatered sludge. In this study, CaO addition followed by mechanical whipping was employed for foaming the dewatered sludge. It was found that the foams were stable and the diameters of bubbles mainly ranged from 0.1 to 0.3 mm. The drying experiments were carried out in a drying oven in the convective mode. The results indicated that foamed sludge at 0.70 g/cm(3) had the best drying performance at each level of temperature, which could save 35-45% drying time to reach 20% moisture content compared with the non-foamed sludge. The drying rate of foamed sludge at 0.70 g/cm(3) was improved with the increasing of drying temperature. The impact of sample thickness on drying rate was not obvious when the sample thickness increased from 2 to 8 mm. Different mathematical models were used for the simulation of foamed sludge drying curves. The Wang and Singh model represented the drying characteristics better than other models with coefficient of determination values over 0.99.

[Effect of temperature on the response characteristics of shortcut nitrification granular sludge]

The experiment was carried out in a sequencing batch reactor (SBR), using granular sludge with 90% shortcut nitrification accumulation ratio, which had been cultivated by the laboratory to seed the reactor. The effects of temperature on characteristics, stability, nitrogen conversion properties and activity of short-cut nitrification granular sludge were investigated. The results show that the temperature has a significant influence on structure and short-cut nitrification performance of short-cut nitrification granular sludge. 30 degrees C was the optimum temperature for shortcut nitrification granular sludge cultivation, and the granules were more compact which led better flocculation and settleability. SVI and average diameter of sludge reached up to 39 mL x g(-1) and 3.03 mm, respectively. The nitrification accumulation was maintained at 96.17% during this period. When the temperature was at 25 degrees C, the granules changed to a loose-structure along with the electronegativity increased as well as the hydrophobicity decreased, which was due to the increase of EPS and decreased ratio of protein to polysaccharide. The granules disintegrated during this period, at the same time, the nitrification accumulation ratio was below 35%. It can be seen that the shortcut nitrification performance was destroyed. At 15 degrees C, the shortcut nitrification sludge also disintegrated and had a looser structure. However, the oxygen penetration depth increased at a lower temperature, which made the relative quantity of ammonia oxidizing bacteria (AOB) in reactor increased, the nitrification accumulation was around 68% ultimately.

Three-dimensional high frequency power Doppler ultrasonography for the assessment of microvasculature during fracture healing in a rat model

We aimed to establish a novel approach with 3D high frequency power Doppler ultrasonography (3D-HF-PDU) to assess microvasculature at the fracture site in rat femurs by comparing with microCT-based microangiography. Twenty-four 9-month-old ovariectomized (OVX) osteoporotic rats and age-matched sham-ovariectomized (Sham) rats were used for establishing closed fracture models on right femora. At 2, 4, and 8 weeks post-operatively, four rats in each group underwent in vivo 3D-HF-PDU scanning for evaluation of vascularization and blood flow at the fracture site. Then the fractured femora were harvested for ex vivo microangiography, and neovasculatures within the callus were reconstructed for vascular volume analysis. Correlation between the vascular volumes of the two methodologies was examined. Both 3D-HF-PDU and microangiography showed a decline of vascular volume at the fracture site from 2 to 8 weeks and a significantly larger volume in the Sham group than the OVX group. A significant linear positive correlation (r = 0.87, p < 0.001) was detected between the volumes measured by the two methodologies. Osteoporotic rats had a diminished angiogenic response and lower blood perfusion than Shams. We believe 3D-HF-PDU is feasible and reproducible for in vivo assessment of microvasculature during femoral fracture healing in rats.

Effects of optical beam angle on quantitative optical coherence tomography (OCT) in normal and surface degenerated bovine articular cartilage

Quantitative measurement of articular cartilage using optical coherence tomography (OCT) is a potential approach for diagnosing the early degeneration of cartilage and assessing the quality of its repair. However, a non-perpendicular angle of the incident optical beam with respect to the tissue surface may cause uncertainty to the quantitative analysis, and therefore, significantly affect the reliability of measurement. This non-perpendicularity was systematically investigated in the current study using bovine articular cartilage with and without mechanical degradation. Ten fresh osteochondral disks were quantitatively measured before and after artificially induced surface degradation by mechanical grinding. The following quantitative OCT parameters were determined with a precise control of the surface inclination up to an angle of 10° using a step of 2°: optical reflection coefficient (ORC), variation of surface reflection (VSR) along the surface profile, optical roughness index (ORI) and optical backscattering (OBS). It was found that non-perpendicularity caused systematic changes to all of the parameters. ORC was the most sensitive and OBS the most insensitive to the inclination angle. At the optimal perpendicular angle, all parameters could detect significant changes after surface degradation (p < 0.01), except OBS (p > 0.05). Nonsignificant change of OBS after surface degradation was expected since OBS reflected properties of the internal cartilage tissue and was not affected by the superficial mechanical degradation. As a conclusion, quantitative OCT parameters are diagnostically potential for characterizing the cartilage degeneration. However, efforts through a better controlled operation or corrections based on computational compensation mechanism should be made to minimize the effects of non-perpendicularity of the incident optical beam when clinical use of quantitative OCT is considered for assessing the articular cartilage.

Evolution of myrmecophytism in western Malesian Macaranga (Euphorbiaceae)

Plants inhabited by ants (myrmecophytes) have evolved in a diversity of tropical plant lineages. Macaranga includes approximately 300 paleotropical tree species; in western Malesia there are 26 myrmecophytic species that vary in morphological specializations for ant association. The origin and diversification of myrmecophytism in Macaranga was investigated using phylogenetic analyses of morphological and nuclear ITS DNA characters and studies of character evolution. Despite low ITS variation, the combined analysis resulted in a well-supported hypothesis of relationships. Mapping myrmecophytism on all most parsimonious trees resulting from the combined analysis indicated that the trait evolved independently between two and four times and was lost between one and three times (five changes). This hypothesis was robust when tested against trees constrained to have three or fewer evolutionary transformations, although increased taxon sampling for the ITS analysis is required to confirm this. Mapping morphological traits on the phylogeny indicated that myrmecophytism was not homologous among lineages; each independent origin involved a suite of different specializations for ant-plant association. There was no evidence that myrmecophytic traits underwent sequential change through evolution; self-hollowing domatia evolved independently from ant-excavated domatia, and different food-body production types evolved in different lineages. The multiple origins of myrmecophytism in Macaranga were restricted to one small, exclusively western Malesian lineage of an otherwise large and nonmyrmecophytic genus. Although the evolution of aggregated food-body production and the formation of domatia coincided with the evolution of myrmecophytism in all cases, several morphological, ecological, and biogeographic factors appear to have facilitated and constrained this radiation of ant-plants.

Domain structure and mutational analysis of T4 polynucleotide kinase

T4 polynucleotide kinase (Pnk) is the founding member of a family of 5'-kinase/3'-phosphatase enzymes that heal broken termini in RNA or DNA by converting 3'-PO(4)/5'-OH ends into 3'-OH/5'-PO(4) ends, which are then suitable for sealing by RNA or DNA ligases. Here we employed site-directed mutagenesis and biochemical methods to dissect the domain structure of the homotetrameric T4 Pnk protein and to localize essential constituents of the apparently separate active sites for the 5'-kinase and 3'-phosphatase activities. We characterized deletion mutants Pnk(42-301) and Pnk(1-181), which correspond to domains defined by proteolysis with chymotrypsin. Pnk(1-181) is a monomer with no 3'-phosphatase and low residual 5'-kinase activity. Pnk(42-301) is a dimer with no 5'-kinase and low residual 3'-phosphatase activity. Four classes of missense mutational effects were observed. (i) Mutations K15A, S16A, and D35A inactivated the 5'-kinase but did not affect the 3'-phosphatase or the tetrameric quaternary structure of T4 Pnk. 5'-kinase activity was ablated by the conservative mutations K15R, K15Q, and D35N; however, kinase activity was restored by the S16T change. (ii) Mutation D167A inactivated the 3'-phosphatase without affecting the 5'-kinase or tetramerization. (iii) Mutation D85A caused a severe decrement in 5'-kinase activity and only a modest effect on the 3'-phosphatase; the nearby N87A mutation resulted in a significantly reduced 3'-phosphatase activity and slightly reduced 5'-kinase activity. D85A and N87A both affected the quaternary structure, resulting in a mixed population of tetramer and dimer species. (iv) Alanine mutations at 11 other conserved positions had no significant effect on either 5'-kinase or 3'-phosphatase activity.

The clinical use of small-dose tetracaine spinal anesthesia for transurethral prostatectomy

In a double-blinded study, we compared conventional dose tetracaine (8 mg), small-dose tetracaine (4 mg) with added fentanyl and epinephrine, and small-dose tetracaine (4 mg) with added fentanyl subarachnoid anesthesia. Forty-five patients scheduled for transurethral resection of prostate (TURP) under subarachnoid anesthesia were randomly assigned to Group 1 (8 mg hyperbaric tetracaine), Group 2 (4 mg hyperbaric tetracaine, 10 microg fen-tanyl, and 0.2 mg epinephrine), and Group 3 (4 mg hyperbaric tetracaine, 10 microg fentanyl, and 0.2 mL saline). Evaluations were performed after spinal anesthesia. Subarachnoid block was successful in all patients except one in Group 1, who required general anesthesia by mask. The median peak sensory levels 10 min after the induction of spinal anesthesia in Group 1 was T8, which was significantly higher than Group 2 and Group 3 (P < 0.05). The time of sensory and motor recovery in Group 3 was less than in Groups 1 and 2 (P < 0.05). Hypotension was observed in four patients in Group 1 and none in Groups 2 and 3. We conclude that small-dose 4-mg hyperbaric tetracaine plus 10 microg fentanyl might provide adequate anesthesia and fewer side effects for TURP when compared with the conventional (8 mg) dose.

IMPLICATIONS

Small-dose hyperbaric tetracaine (4 mg with 10 microg fentanyl added) may provide adequate anesthesia and fewer side effects for transurethral resection of the prostate.

Axillary brachial plexus block with patient controlled analgesia for complex regional pain syndrome type I: a case report

BACKGROUND AND OBJECTIVES

Brachial plexus block (BPB) has been cited as a treatment modality for complex regional pain syndrome type I (CRPS I) of the upper limb. However, there are no reports using axillary BPB with patient controlled analgesia (PCA) for the treatment of CRPS I. This report is based on the retrospective observations of the outcome and effects of axillary BPB with PCA in a patient with CRPS I.

CASE REPORT

A 32-year-old man suffered from CRPS I of the right upper limb after surgical release of carpal tunnel syndrome of the right hand. Symptoms and signs over the right hand were alleviated under rehabilitation and conventional pharmacological management, but severe painful swelling of the right wrist persisted. Axillary BPB with PCA was performed on the 32nd postoperative day, which soon resulted in significant reduction of pain with gradual improvement of function of the right wrist.

CONCLUSIONS

Axillary BPB with PCA may provide patients with CRPS I of the upper limb a feasible and effective treatment. .

Home-based patient-controlled epidural analgesia with bupivacaine for patients with intractable herpetic neuralgia

This clinical report is based on retrospective observation of the outcome and effects of patient-controlled epidural analgesia (PCEA) with bupivacaine infusion administered at home to five patients with intractable herpetic neuralgia. All patients had severe pain (9 or 10 visual analogue scale [VAS]points) confined to the affected dermatomes, which was refractory to medication. The interval between zoster onset and PCEA application ranged from 27 to 60 days (mean, 37.2 d). The average daily amount of bupivacaine used was 36.5 to 91.2 mg (mean +/- standard deviation, 62.4 +/- 19.7 mg). The duration of PCEA therapy ranged from 10 to 28 days (18.4 +/- 7.6 d). One patient developed drug tolerance. All treatments resulted in effective and satisfactory pain relief (VAS, 0-3), with increase in physical activities to normal levels and easing of sleep and appetite impairment. No deleterious effects were found during PCEA therapy. After discontinuation of PCEA, two patients did not complain of pain but still had slight paresthesia, one of them required low-dose antidepressant for 17 days; three patients continued to have occasional sharp pain (VAS, 2-3) and required low-dose antidepressant and analgesic as-needed for one to six months. These results suggest that PCEA with bupivacaine infusion provides effective pain relief in patients with intractable herpetic neuralgia and is a feasible and effective home treatment modality with limited side effects.

[Surgical treatment for the recurrent patients after palatopharyngoplasty]

OBJECTIVE

To study the surgical treatment for the recurrent patients after palatopharyngoplasty (PPP).

METHOD

Five patients which were confirmed recurrence by sleep survey and examinations were reported.

RESULT

The pharyngeal cavity was narrower obviously ten months after ppp than before ppp. The anteroposterior and transverse distances were (4.06 +/- 2.94) mm and (11.40 +/- 4.16) mm respectively. After dilatation, the distances were (11.90 +/- 3.25) mm and (21.00 +/- 4.18) mm separately, and were increased significantly than before (P < 0.01). Two patients were cured and three cases marked, and all patients were not recurrent post-operation with no complications.

CONCLUSION

The recurrence was mainly concerned with the unsuitable manipulation in PPP. Selecting the cooperation and proper surgical treatment, the better effect was also obtained for the recurrent patients.

Structure and mechanism of yeast RNA triphosphatase: an essential component of the mRNA capping apparatus

RNA triphosphatase is an essential mRNA processing enzyme that catalyzes the first step in cap formation. The 2.05 A crystal structure of yeast RNA triphosphatase Cet1p reveals a novel active site fold whereby an eight-stranded beta barrel forms a topologically closed triphosphate tunnel. Interactions of a sulfate in the center of the tunnel with a divalent cation and basic amino acids projecting into the tunnel suggest a catalytic mechanism that is supported by mutational data. Discrete surface domains mediate Cet1p homodimerization and Cet1p binding to the guanylyltransferase component of the capping apparatus. The structure and mechanism of fungal RNA triphosphatases are completely different from those of mammalian mRNA capping enzymes. Hence, RNA triphosphatase presents an ideal target for structure-based antifungal drug discovery.

The dose effect of propofol on cerebrovascular reactivity to carbon dioxide in rabbits

BACKGROUND

Propofol has several properties beneficial to intracranial operation such as reduction in cerebral metabolic rate and cerebral blood flow (CBF) in a dose-dependent manner while leaving autoregulation intact. Several studies have demonstrated that the responsiveness of CBF to changes in arterial carbon dioxide tension (PaCO2) is maintained during propofol anesthesia in both humans and animals. These studies showed a significant difference in the CBF-CO2 reactivity slope between awake and propofol anaesthetized groups, but no comparison with different doses of propofol was made. To determine the dose effect of propofol on cerebrovascular CO2 reactivity, we used laser Doppler flowmetry (LDF) to detect the changes of CBF during propofol anesthesia.

METHODS

Ten rabbits were studied using LDF on the parietal cortex. After surgical preparation, anesthesia was maintained with 66% N2O in O2, morphine 10 mg/kg and pancuronium. Three experimental conditions were studied sequentially with intravenous administration of the following drugs: (1) normal saline (control), (2) propofol 20 mg/kg/h i.v., (3) propofol 40 mg/kg/h i.v. Mean arterial pressure, rectal temperature and hematocrit were kept constant. The arterial carbon dioxide tension (PaCO2) was adjusted to three levels during each condition: 20-25 mmHg (hypocapnia), 35-40 mmHg (normocapnia) and 45-50 mmHg (hypercapnia). CBF was measured continuously and recorded after the target PaCO2 had been reached.

RESULTS

There were no differences among all conditions in mean arterial pressure and heart rate. The changes of CBF as PaCO2 increased at the three different CO2 levels during each of the conditions were significantly different. The slope of CBF-CO2 reactivity among three different propofol doses was not significantly different.

CONCLUSIONS

These data indicate that cerebral vasomotor responsiveness to CO2 during propofol anesthesia is preserved and that the slope of CBF-CO2 reactivity is independent of propofol doses as mean arterial blood pressure is maintained.

Differential effects of camptothecin derivatives on topoisomerase I-mediated DNA structure modification

The effects of eleven camptothecin derivatives on calf thymus topoisomerase I-mediated cleavage of synthetic DNA duplex have revealed that the A ring of camptothecin is very important for its biochemical activity. Depending on the type, number, and location of substituents, highly active or inactive analogues were obtained. The persistence of CPT-induced topoisomerase I-DNA covalent binary complexes was investigated by using as substrates DNA containing several good topoisomerase I cleavage sites, or else a synthetic DNA duplex of defined structure with a single high-efficiency cleavage site. The ligation kinetics at a given topoisomerase I cleavage site were sometimes quite different in the presence of CPT derivatives whose structures were closely related. Even in the presence of a single CPT analogue, topoisomerase I-DNA covalent binary complexes underwent ligation with different kinetics, presumably reflecting a dependence on DNA sequences flanking the individual topoisomerase I cleavage sites. Individual camptothecin derivatives also exhibited a spectrum of inhibitory potentials in blocking the topoisomerase I-mediated rearrangement of branched, nicked, and gapped DNA duplex substrates; in some cases the potencies of inhibition observed in these assays for individual camptothecin analogues were quite different than those determined for stabilization of the unmodified DNA-topoisomerase I binary complex.

Mutational analysis of 26 residues of vaccinia DNA topoisomerase identifies Ser-204 as important for DNA binding and cleavage

Vaccinia DNA topoisomerase, a 314 amino acid type I enzyme, catalyzes the cleavage and rejoining of DNA strands through a DNA-(3'-phosphotyrosyl)-enzyme intermediate formed at a specific target sequence, 5'-(C/T)CCTT downward arrow. To identify amino acids that participate in the DNA binding and transesterification steps, we introduced alanine substitutions at 18 positions within a centrally located 27 amino acid segment (181-RLYKPLLKLTDDSSPEEFLFNKLSERK-207) and at 8 positions near the N-terminus (1-MRALFYKDGK-10). All mutant proteins except two displayed wild-type activity in relaxing supercoiled DNA. F200A and S204A exhibited reduced rates of relaxation and were subjected to a kinetic analysis of the strand cleavage reaction under single-turnover and equilibrium conditions. The F200A and S204A mutations reduced the rate of single-turnover DNA cleavage by factors of 5 and 70, respectively. Both mutations shifted the cleavage-religation equilibrium in favor of the noncovalently bound state. The S204A mutation reduced the affinity of topoisomerase for CCCTT-containing DNA, but did not alter the site-specificity of DNA cleavage. Vaccinia residue Ser-204, which is conserved in all poxvirus topoisomerases, but not in the cellular homologues, may contribute to the unique cleavage site specificity of the poxvirus enzymes. Phe-200 is conserved in all members of the type IB topoisomerase family.

Deletions at the carboxyl terminus of vaccinia DNA topoisomerase affect DNA binding and enhance distributivity in DNA relaxation

Vaccinia topoisomerase relaxes DNA through the formation of a covalent DNA-(3'-phosphotyrosyl)protein intermediate at sites containing the sequence 5'-(T/C)CCTT/. The active site, Tyr-274, is situated near the carboxyl terminus of the 314 amino acid enzyme. Here, we report the effects of serial C-terminal deletions. Removal of five amino acids had no effect on topoisomerase activity. However, deletion of 10, 15, or 20 amino acids rendered the enzyme distributive in DNA relaxation, incrementally slowed the rate of single-turnover DNA cleavage, and progressively diminished DNA binding affinity, without altering the sequence specificity of DNA cleavage. These effects lead us to speculate that the region downstream of the active site, which is not well-conserved among the poxvirus-encoded topoisomerases, is a component of the proposed circumferential interface between the enzyme and duplex DNA.

Mutational analysis of 39 residues of vaccinia DNA topoisomerase identifies Lys-220, Arg-223, and Asn-228 as important for covalent catalysis

Vaccinia DNA topoisomerase, a 314-amino acid type I enzyme, catalyzes the cleavage and rejoining of DNA strands through a DNA-(3'-phosphotyrosyl)-enzyme intermediate. To identify amino acids that participate in the transesterification reaction, we introduced alanine substitutions at 39 positions within a conserved 57amino acid segment upstream of the active-site tyrosine. Purified wild type and mutant proteins were compared with respect to their activities in relaxing supercoiled DNA. The majority of mutant proteins displayed wild type topoisomerase activity. Mutant enzymes that relaxed DNA at reduced rates were subjected to kinetic analysis of the strand cleavage and religation steps under single-turnover and equilibrium conditions. For the wild type topoisomerase, the observed single-turnover cleavage rate constant (kcl) was 0.29 s-1 and the cleavage-religation equilibrium constant (Kcl) was 0.22. The most dramatic mutational effects were seen with R223A; removal of the basic side chain reduced the rates of cleavage and religation by factors of 10(-4.3) and 10(-5.0), respectively, and shifted the cleavage-religation equilibrium in favor of the covalently bound state (Kcl = 1). Introduction of lysine at position 223 restored the rate of cleavage to 1/10 that of the wild type enzyme. We conclude that a basic residue is essential for covalent catalysis and suggest that Arg-223 is a constituent of the active site. Modest mutational effects were observed at two other positions (Lys-220 and Asn-228), at which alanine substitutions slowed the rates of strand cleavage by 1 order of magnitude and shifted the equilibrium toward the noncovalently bound state. Arg-223 and Lys-220 are conserved in all members of the eukaryotic type I topoisomerase family; Asn-228 is conserved among the poxvirus enzymes.

Inhibition of topoisomerase I function by coralyne and 5,6-dihydrocoralyne

The antitumor agent coralyne and a number of structural analogues were found to be inhibitors of DNA topoisomerase I and were characterized biochemically. Several of these analogues stabilized the covalent binary complex formed between calf thymus topoisomerase I and pSP64 plasmid DNA; coralyne and 5,6-dihydrocoralyne had the greatest potency as inhibitors in this assay. In common with camptothecin, the effects of coralyne and 5,6-dihydrocoralyne were reversed in the presence of increasing salt concentration or temperature, consistent with the interpretation that both functioned mechanistically in a fashion analogous to camptothecin. The sequence specificity of DNA cleavage by coralyne and 5,6-dihydrocoralyne was also studied in comparison with camptothecin using a 471-bp DNA duplex as a substrate for topoisomerase I. Seven sites of cleavage were apparent, four of which were shared in common by coralyne, 5,6-dihydrocoralyne and camptothecin. Coralyne and 5,6-dihydrocoralyne produced cleavage at one sequence, 5'-TCTC decreases GTAA=3', that was not apparent in the presence of camptothecin; correspondingly, two cleavage bands appeared only when camptothecin was present. Coralyne and 5,6-dihydrocoralyne also inhibited topoisomerase I-mediated relaxation of supercoiled plasmid DNA. Coralyne was the most potent inhibitor of DNA relaxation; the effects of camptothecin and 5,6-dihydrocoralyne were roughly equal. At high concentrations, coralyne completely suppressed the formation of the topoisomerase I-DNA covalent binary complex.

Inhibition of topoisomerase I function by nitidine and fagaronine

The benzophenanthridine alkaloids nitidine and fagaronine were characterized as inhibitors of topoisomerase I function. In common with the antitumor agent camptothecin, both nitidine and fagaronine stabilized the covalent binary complex formed between calf thymus topoisomerase I and DNA. The effects of these compounds were readily apparent at 0.15-0.3 microM concentrations. Both nitidine and fagaronine inhibited the topoisomerase I-mediated relaxation of supercoiled pSP64 plasmid DNA more effectively than camptothecin; unlike camptothecin, both of these benzophenanthridine alkaloids also bound directly to and mediated the unwinding of B-form DNA. Nitidine and fagaronine were also studied in comparison with camptothecin to determine the sequence specificity of DNA breaks produced from a 32P-end-labeled duplex in the presence of topoisomerase I. All three compounds produced very similar cleavage patterns. The specificity of nitidine and fagaronine for inhibiting topoisomerase I function was studied by measuring the effects of the compounds on the unknotting of P4 DNA by calf thymus topoisomerase II. Moderate inhibition of topoisomerase II-mediated unknotting was obtained, but only in the presence of high (i.e., 40 microM) concentrations of nitidine and fagaronine. In comparison, doxorubicin inhibited topoisomerase II to the same extent as nitidine and fagaronine when it was employed at 2.5 microM concentration and was strongly inhibitory when employed at 10 microM concentration.

A study on the ecological habit of Armigeres subalbatus in Dawa area of the Mengshan Mountain in Shandong Province

Armigeres subalbatus (A.s.) was reported in Shandong Province for the first time in 1965 and found in five counties of south Shandong including Pingyi, Linyi etc. in 1986. In Dawa area of the Mengshan mountain A.s. alults could be found in the first ten days of May, which increased in number in July, and become the dominant species in mosquito colonies in Aug. and Sept., then decreased gradually in number in Oct. and disappeared in Nov. There were two peaks of activity and blood-sucking behavior during the 24 hours of a day, one at dusk and the other at dawn. When the temperature dropped to 16 degrees C and below in the last ten days of Oct., the wigglers began their diapause period. The survival ratio reached 90.5% after 12 h freezing at -5 degrees C and none survived after 60 hours freezing. When the temperature rose to 17 degrees C and above the over-winterting larvae developed into adults, which could suck blood only at the temperature above 17.5 degrees C.

Raman compensation for a two-channel soliton-based optical fiber communication system

A technique of Raman compensation for a two-channel soliton-based fiber communication system is introduced. By fixing the wavelength spacing between two channels, one can calculate the pumping wavelength and intensity in such a way that balance between loss and gain is reached for each channel. In this computation the Raman conversion between two channels plays an important role in simultaneous compensation for both channels.