Cytotoxic steroidal saponins from the rhizomes of Paris fargesii var. Petiolata

Phytochemical investigation on the rhizomes of Paris fargesii var. petiolata (Baker ex C. H. Wright) Wang et Tang led to the isolation of five previously undescribed steroidal saponins, parpetiosides A-E (1-5), and six known analogs (6-11). Their structures were established by extensive spectroscopic data analysis and chemical methods. Compound 5 was a rare steroidal saponin with disaccharide moiety linked at C-26 of dehydrokryptogenin that was hardly seen in the genus Paris. The cytotoxicities of the isolated compounds against three human cancer cell lines (U87, HepG2 and SGC-7901) were evaluated, and compound 1 displayed certain inhibitory effect with IC₅₀ values of 8.02 ± 0.45, 8.24 ± 0.57 and 6.20 ± 0.79 μM, respectively. Moreover, the preliminary mechanism of 1 inhibiting the proliferation of the three cancer cell lines might be related to cell cycle distribution and the induction of S phase arrest.

Flexible Pressure Sensor with an Excellent Linear Response in a Broad Detection Range for Human Motion Monitoring

Pressure sensing is highly demanding in wearable devices, robotics, and artificial intelligence, whereas it is still a big challenge to develop a pressure sensor with an excellent linear response in a broad detection range. Herein, a flexible and porous carbon nanotube (CNT)/carbon black (CB)/carbonyl iron powder (CIP)/silicone composite is proposed by a simple strategy of mixing, curing, and washing. Due to the porous structure induced by the sacrifice of sugar particles, an excellent linear response (R² = 0.999) is achieved for the composite sensor by manipulating the contributions of contact resistance and tunnel resistance to the sensing performance via the alternation of CB and CNT contents. Moreover, the porous structure donates the composite sensor a low compressive modulus at a low pressure level, while the CIPs introduced lead to a high compressive modulus at a high pressure level with the assistance of an external magnetic field. As a result, the sensor produced has a wide linear response range of 80 Pa to 220 kPa, much wider than most of the linear response pressure sensors reported previously. The wide detection range is demonstrated by cyclic pressure tests in the frequency range of 0.1-5 Hz, durability tests, and monitoring human or robot motions including breathing, walking, lifting, and boxing, etc. Taking the advantages of low cost, high sensitivity, and excellent linear response in a wide pressure range, the current composite sensor is promising for precise monitoring of human motions and delicate controlling of robots.

Proteomic profiling reveals mitochondrial toxicity of nanosilver and silver nitrate in the gill of common carp

Mitochondria are recognized as an important target organelle for the toxicity of nanomaterials. Although the toxic effects of silver nanoparticles (AgNPs) on mitochondria have been widely reported, the mechanism behind the toxicity remains unclear. In this study, the effects of two forms of silver (AgNPs and AgNO₃) on carp gill mitochondria were investigated by analyzing the mitochondrial ultrastructure, physicochemical properties of mitochondrial membrane, and mitochondrial proteomics. After exposure of common carp to AgNPs (0.75 mg/L) and AgNO₃ (0.05 mg/L) for 96 h, both forms of silver were shown to cause gill mitochondrial lesions, including irregular shape, loss of mitochondrial cristae, and increased mitochondrial membrane permeability. Proteomics results revealed that AgNPs and AgNO₃ induced 362 and 297 differentially expressed proteins (DEPs) in gill mitochondria, respectively. Among the DEPs, 244 were shared between AgNPs and AgNO₃ treatments. These shared proteins were mainly distributed in the mitochondrial membrane and matrix, and were significantly enriched in the tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathway. The functional annotation of DEPs induced by both silver forms was mainly involved in energy production and conversion. These results indicated that the toxic mechanism of AgNPs and AgNO₃ on gill mitochondria were comparable and the two forms of silver caused mitochondrial dysfunction in fish gills by inhibiting the TCA cycle and disrupting the electron transport chain.

[Association of blood lead and blood selenium with serum high-sensitivity C-reactive protein among Chinese adults aged 19 to 79 years]

Objective: To investigate the association of blood lead and blood selenium with serum high-sensitivity C-reactive protein (hs-CRP) among Chinese adults aged 19 to 79 years. Methods: The participants were enrolled from the first wave of China National Human Biomonitoring (CNHBM) conducted from 2017 to 2018. 10 153 participants aged 19 to 79 years were included in this study. Fasting blood samples were obtained from participants. Lead and selenium in whole blood and hs-CRP in serum were measured. Individuals with hs-CRP levels above 3.0 mg/L were defined as elevated hs-CRP. Generalized linear mixed models and restricted cubic spline models were used to analyze the association of blood lead and blood selenium with elevated hs-CRP. Logistic regression models were used to analyze the multiplicative scale and additive scale interaction between blood lead and blood selenium on elevated hs-CRP. Results: The age of participants was (48.91±15.38) years, of which 5 054 (61.47%) were male. 1 181 (11.29%) participants were defined as elevated hs-CRP. After multivariable adjustment, results from generalized linear models showed that compared with participants with the lowest quartile of blood lead, the OR (95%CI) of elevated hs-CRP for participants with the second, third, and highest quartiles were 1.14 (0.94-1.37), 1.25 (1.04-1.52) and 1.38 (1.13-1.68), respectively. When compared with participants with the lowest quartile of blood selenium, the OR (95%CI) of elevated hs-CRP for participants with the second, third and highest quartiles were 0.86 (0.72-1.04), 0.91 (0.76-1.11), and 0.75 (0.61-0.92), respectively. Results from the interaction analysis showed no significant interaction between lead and selenium on elevated hs-CRP. Conclusion: Blood concentration of lead was positively associated with elevated serum hs-CRP, and blood concentration of selenium was inversely related to elevated hs-CRP, while blood lead and selenium did not present interaction on elevated hs-CRP.

Integration of transcriptomics and metabolomics reveals damage and recovery mechanisms of fish gills in response to nanosilver exposure

Toxic effects of silver nanoparticles (AgNPs) on fish gills have been widely reported but the recoverability of AgNPs-induced fish gill injuries is still unknown. In this study, combined multiomics and conventional toxicological analytical methods were used to investigate the changes in the gills of common carp responses to AgNPs (0.1 mg/L) toxicity after 24 h exposure and 7-day recovery. Conventional toxicological results showed that AgNPs exposure significantly increased silver content in gills and caused epithelial hyperplasia and lamellar fusion. After the recovery period, the silver content in fish gills significantly decreased; accompanied by the disappearance of histopathological characteristics in fish gills. Multiomics results revealed that AgNPs exposure resulted in the differential expression of 687 genes and 96 metabolites in fish gills. These differentially expressed genes (DEGs) and metabolites mainly participate in amino acid, carbohydrate, and lipid metabolisms, and are significantly enriched in the tricarboxylic acid (TCA) cycle. After the recovery period, the number of DEGs and metabolites in gills decreased to 33 and 90, respectively. Moreover, DEGs and metabolites in the TCA cycle recovered to control levels. In summary, the present study found that AgNPs-induced fish gill toxicity showed potential recoverability at molecular and phenotype levels.

HPV16 infection promotes an M2 macrophage phenotype to promote the invasion and metastasis of esophageal squamous cell carcinoma

OBJECTIVES

High-risk human papillomavirus (HR-HPV) is an important risk factor for esophageal cancer. Macrophages constitute a crucial immune medium for regulating HPV-related tumors; however, the specific regulatory mechanisms remain unknown. Therefore, the purpose of our current study was to investigate the mechanism by which HPV16E6 regulates macrophages to promote the invasion and metastasis of esophageal cancer.

METHODS

HPV16E6 infection was detected by polymerase chain reaction. Immunohistochemistry was used to verify the distribution of tumor-associated macrophages (TAMs) and MMP-9 expression in esophageal squamous cell carcinoma tissues (ESCCs), and cancer adjacent normal tissues (CANs) from Kazakh patients. ESCC cells were transfected with a plasmid over-expressing HPV16E6 and non-contact cocultured with macrophages.

RESULTS

The infection rate of HPV16E6 in Kazakh ESCCs was clearly higher than that in CANs (P < 0.05). The density of CD163-positive TAMs was significantly positively correlated with HPV16E6 infection in ESCCs (P < 0.05). After coculturing macrophages and EC9706 cells transfected with the HPV16E6 plasmid, the phenotype of macrophages transformed into M2 macrophages. The migration and invasion ability of ESCC cells were higher in the HPV16E6-transfected and coculture group than in the HPV16E6 empty vector-transfected and non-cocultured HPV16E6-transfected groups (all P < 0.05). The density of M2-like TAMs in ESCCs was positively correlated with the level of MMP-9 expression. MMP-9 expression in the HPV16E6-ESCC coculture macrophages group was substantially higher than that in controls (all P < 0.05).

CONCLUSIONS

HPV16 infection mediates tumor-associated macrophages to promote ESCC invasion and migration.

Application of Eye Tracker in Lie Detection

Objective To investigate the application value of eye tracking in lie detection. Methods The 40 subjects were randomly divided into two groups. The pupil diameter, fixation duration, points of fixation and blink frequency of the subjects in the experimental group in observing target stimulation and non-target stimulation were recorded with eye tracker after they accomplished the mock crime. The eye movement parameters of subjects in the control group were directly collected. The differences in eye movement parameters of the experimental group and the control group in observing target stimulation and non-target stimulation were analyzed by t-test. Pearson coefficient analysis of correlation between eye movement parameters that had differences was conducted. The effectiveness of eye movement parameters to distinguish between the experimental group and the control group was calculated by the receiver operator characteristic （ROC） curve. Results Participants from the experimental group had shorter average pupil diameter, longer average fixation duration and fewer fixation points （P<0.05）, but the differences in blink frequency had no statistical significance. The differences in the above indicators of the control group in observing target stimulation and non-target stimulation had no statistical significance. The average fixation duration showed a negative correlation with fixation points （r=-0.255, P<0.05）; the average fixation duration showed a negative correlation with average pupil diameter （r=-0.218, P<0.05）; the fixation points showed a positive correlation with average pupil diameter （r=0.09, P<0.05）. The area under the curve of average pupil diameter, average fixation duration and fixation points was 0.603, 0.621 and 0.580, respectively. Conclusion The average pupil diameter, average fixation duration and fixation points obtained by the eye tracker under laboratory conditions can be used to detect lies.

Magnetoelectric Coupling by Piezoelectric Tensor Design

Strain-coupled magnetoelectric (ME) phenomena in piezoelectric/ferromagnetic thin-film bilayers are a promising paradigm for sensors and information storage devices, where strain manipulates the magnetization of the ferromagnetic film. In-plane magnetization rotation with an electric field across the film thickness has been challenging due to the large reduction of in-plane piezoelectric strain by substrate clamping, and in two-terminal devices, the requirement of anisotropic in-plane strain. Here we show that these limitations can be overcome by designing the piezoelectric strain tensor using the boundary interaction between biased and unbiased piezoelectric. We fabricated 500 nm thick, (001) oriented [Pb(Mg_1/3Nb_2/3)O₃]_0.7-[PbTiO₃]_0.3 (PMN-PT) unclamped piezoelectric membranes with ferromagnetic Ni overlayers. Guided by analytical and numerical continuum elastic calculations, we designed and fabricated two-terminal devices exhibiting electric field-driven Ni magnetization rotation. We develop a method that can apply designed strain patterns to many other materials systems to control properties such as superconductivity, band topology, conductivity, and optical response.

Application of Nonlinear Optical Microscopic Imaging Technology for Quality Assessment of Donor Kidneys

BACKGROUND

Nonlinear optical microscopic (NLOM) imaging technique shows its high resolution imaging features in histocytology. The purpose of this study was to investigate NLOM imaging technique as a useful tool for a donor kidney quality assessment.

MATERIALS AND METHODS

Eighty-three pretransplant kidney biopsies from adult donors were analyzed retrospectively. Each specimen was paraffin-embedded and sectioned into 2 consecutive 5-μm thick sections. One section was stained with Masson trichrome, and the other was left unstained for NLOM imaging using second harmonic generation combined with two-photon excited fluorescence (SHG/TPEF). The pretransplant kidney quality was assessed by an experienced pathologist using the Remuzzi scoring system, which characterizes renal tissue morphology into 4 aspects: tubular atrophy, interstitial fibrosis, glomerulosclerosis, and vascular injury. The K coefficient was used to measure the consistency of the Remuzzi scores between conventional Masson trichrome stained images and SHG/TPEF images.

RESULTS

NLOM imaging technology can capture high-resolution tissue images from unstained renal tissue, is easy to operate, and shortens time-consuming histological processing procedures. No significant differences (P > .05) were found between the Remuzzi scores of the SHG/TPEF images and the Masson trichrome stained images. The high κ coefficients (0.804-0.895) showed a good consistency between these 2 techniques.

CONCLUSION

The NLOM technique is suitable for renal tissue imaging and could potentially be used for routine pretransplant kidney evaluation in clinical settings.

[Diagnostic value of D-dimer combined with Wells score for suspected pulmonary embolism]

OBJECTIVE

To evaluate the value of conventional and age-adjusted D-dimer cut-off value combined with 2-level Wells score for diagnosis of suspected pulmonary embolism.

METHODS

In the study, 335 patients with suspected pulmonary embolism who visited Peking University People's Hospital were enrolled retrospectively, then 274 patients with age over fifty years were chosen. The 2-level Wells score was applied to evaluate the clinical probability of pulmonary embolism, the diagnostic value of traditional D-dimer cut-off value (500 μg/L) and age adjusted D-dimer cut-off value (age×10 μg/L above 50 years) combined with Wells score no greater than 4 were compared. Computed tomography pulmonary arteriography (CTPA) was considered as the gold standard for diagnosis of pulmonary embolism.

RESULTS

(1) The area under a receiver operating characteristic (ROC) curve (AUC) in analysis of the combination of Wells score no greater than 4 and traditional D-dimer cut-off value was 0.764 (95%CI: 0.703-0.818). On the other hand, the AUC in a ROC analysis of the combination of Wells Score no greater than 4 and age-adjusted D-dimer cut-off value was 0.814 (95%CI:0.756-0.863). These two results did not differ statistically (Z=0.05, P=0.121). (2) The sensitivity, specificity, positive predictive value, negative predictive value and Youden index of the diagnosis of pulmonary embolism of the combination of traditional D-dimer cut-off value and 2-level Wells Score were 100%, 48.9%, 28.8%, 100%, and 0.49, respectively. Meanwhile, the sensitivity, specificity, positive predictive value, negative predictive value and Youden index of the diagnosis of pulmonary embolism of the combination of age-adjusted D-dimer cut-off value and 2-level Wells Score were 97.4%, 62.3%, 35.5%, 99.1%, and 0.60, respectively. Compared with using traditional D-dimer cut-off value, using age-adjusted D-dimer cut-off value could improve the diagnosis specificity (traditional D-dimer cut-off value group: 48.9%, age-adjusted D-dimer cut-off value group: 62.3%) of pulmonary embolism without reducing the sensitivity (traditional D-dimer cut-off value group: 100%, age-adjusted D-dimer cut-off value group: 99.1%). (3) Among the 222 patients with Wells Score no greater than 4, 90 patients were with D-dimer less than traditional cut-off value (500 μg/L), and 25 patients (account for 11.3% of all 222 patients) were with D-dimer between traditional cut-off value and age-adjusted cut-off value.

CONCLUSION

The application of age-adjusted D-dimer cut-off value can improve the diagnostic specificity of pulmonary embolism in patients over 50 years, without reducing the sensitivity. It can be used for ruling out suspected pulmonary embolism safely.

Protective role of microRNA-221 in Parkinson's disease

OBJECTIVE

The present study aimed to explore the role and the underlying mechanism of miR-221 in Parkinson's Disease.

MATERIALS AND METHODS

To perform our investigation, a PD cell model was created by using 6-OHDA. Cell viability and proliferation assays, and flow cytometry analysis were performed to detect cell viability and apoptosis. The qRT-PCR and western blotting were used for gene and protein level detection.

RESULTS

We found that the expression of miRNA-221 is significantly lower in 6-OHDA treated PC12 pheochromocytoma cells compared to the normal cells. The results of further analysis indicated that miR-221 mimic significantly promoted the cell viability and proliferation of PC12 cells treated with 6-OHDA. MiR-221 mimic significantly inhibited 6-OHDA-treated PC12 cells from apoptosis. These effects were eliminated by PTEN over-expression. We also revealed that PTEN was a direct target gene of miR-221. Moreover, we found miR-221 mimic significantly promoted the phosphorylation of AKT in PC12 cells treated with 6-OHDA, and over-expression of PTEN could eliminate this effect.

CONCLUSIONS

MiR-221 plays a protective role in Parkinson's Disease via regulating PC12 cell viability and apoptosis by targeting PTEN. Therefore, miR-221 may serve as a potential therapeutic target for Parkinson's disease treatment (Fig. 3, Ref. 27).

[The distribution characteristics of etiology of chronic cough in Lanzhou]

OBJECTIVE

To explore the distribution characteristics of etiology and clinical feature of chronic cough in Lanzhou.

METHODS

Based on the guidelines of the diagnostic process of chronic cough in China, data of medical history and physical examinations were collected, and chest X-ray, pulmonary function plus airway hyperresponsiveness, induced sputum eosinophils, sinus X-ray or CT, 24 h esophageal pH monitoring, chest high-resolution CT and bronchoscopy were performed accordingly for outpatients with chronic cough. The cause of chronic cough was identified by the test results and treatment response. The results were compared with those reported previously in other areas of China.

RESULTS

A total of 173 patients with completed data were collected, including 90 males and 83 females.The causes were as follows: 45 cases (26.01%) of cough variant asthma, 35 (20.23%) upper airway cough syndrome, 20 (11.56%) allergic cough, 17 (9.83%) chronic pharyngitis, 14 (8.09%) gastroesophageal reflux, 14 (8.09%)postinfectious, 13 (7.51%) eosinophilic bronchitis, 8 (4.62%) chronic bronchitis, 4 (2.31%) cough associated with ACEI, 3 (1.73%) bronchial tuberculosis, 2 (1.16%) pulmonary fibrosis and bronchiectasis repectively. The causes of the remaining 14 patients (8.09%)were unknown. The causes of chronic cough were identified in 159 patients (91.91%), of which 141 (88.68%) with a single cause and 18(11.32%)with more than 2 etiological factors.The percentage of cough variant asthma in our series was significantly higher than that reported in Guangzhou (13.6%, χ(2)=5.60, P=0.018, P<0.05), but lower than that reported in Shenyang (39.4%, χ(2)=7.91, P=0, 004, P<0.01). The percentage of allergic cough was higher than that reported in Beijing (3.3%, χ(2)=6.66, P=0.010, P<0.05), and that of eosinophilic bronchitis was lower than those reported in Guangzhou(22.4%, χ(2)=22.38, P=0.000, P<0.01) and Shenyang (12.5%, χ(2)=8.09, P=0.005, P<0.01). The percentage of esophageal reflux cough was lower than that reported in Beijing (20.3%, χ(2)=9.40, P=0.002, P<0.01) but higher than that reported in Shenyang (1.9%, χ(2)=3.98, P=0.036, P<0.05).

CONCLUSION

In Lanzhou, cough variant asthma, upper airway cough syndrome, allergic cough, chronic pharyngitis and gastroesophageal reflux were the main causes of chronic cough, and the etiological distribution was different from Guangzhou, Beijing, Shenyang and other areas.

Magnetization Reversal by Out-of-plane Voltage in BiFeO3-based Multiferroic Heterostructures

Voltage controlled 180° magnetization reversal has been achieved in BiFeO3-based multiferroic heterostructures, which is promising for the future development of low-power spintronic devices. However, all existing reports involve the use of an in-plane voltage that is unfavorable for practical device applications. Here, we investigate, using phase-field simulations, the out-of-plane (i.e., perpendicular to heterostructures) voltage controlled magnetism in heterostructures consisting of CoFe nanodots and (110) BiFeO3 thin film or island. It is predicted that the in-plane component of the canted magnetic moment at the CoFe/BiFeO3 interface can be reversed repeatedly by applying a perpendicular voltage across the bottom (110) BiFeO3 thin film, which further leads to an in-plane magnetization reversal in the overlaying CoFe nanodot. The non-volatility of such perpendicular voltage controlled magnetization reversal can be achieved by etching the continuous BiFeO3 film into isolated nanoislands with the same in-plane sizes as the CoFe nanodot. The findings would provide general guidelines for future experimental and engineering efforts on developing the electric-field controlled spintronic devices with BiFeO3-based multiferroic heterostructures.

Effect of strain on voltage-controlled magnetism in BiFeO₃-based heterostructures

Voltage-modulated magnetism in magnetic/BiFeO₃ heterostructures can be driven by a combination of the intrinsic ferroelectric-antiferromagnetic coupling in BiFeO₃ and the antiferromagnetic-ferromagnetic exchange interaction across the heterointerface. However, ferroelectric BiFeO₃ film is also ferroelastic, thus it is possible to generate voltage-induced strain in BiFeO₃ that could be applied onto the magnetic layer across the heterointerface and modulate magnetism through magnetoelastic coupling. Here, we investigated, using phase-field simulations, the role of strain in voltage-controlled magnetism for these BiFeO₃-based heterostructures. It is predicted, under certain condition, coexistence of strain and exchange interaction will result in a pure voltage-driven 180° magnetization reversal in BiFeO₃-based heterostructures.

Human papillomavirus type 16 infection may be involved in esophageal squamous cell carcinoma carcinogenesis in Chinese Kazakh patients

The aim of this study was to investigate human papillomavirus type 16 (HPV16) prevalence in esophageal squamous cell carcinoma (ESCC) in Xinjiang Kazakh patients and its role in ESCC carcinogenesis. One hundred and fifty cases of ESCC and 150 cases of corresponding normal esophageal mucosa (CNGM) samples were collected from north Xinjiang where the Kazakh ethnic group has lived since ancient times. HPV16 infection in ESCC and CNGM was detected by genotype-specific polymerase chain reaction. HPV16 DNA was detected in 55 of 150 ESCC samples (36.7%) and 24 of 150 corresponding normal esophageal mucosa samples (16%) with significant differences (P < 0.001, odds ratio = 3.039, 95% confidence interval: 1.756-5.260). No statistically significant correlations were found between HPV16 infection and the age or gender of patients, tumor site, tumor cell differentiation, or lymph node metastasis (P > 0.05). HPV16 infection is common in cases of ESCC in the Kazakh ethnic group in Xinjiang and may be involved in ESCC carcinogenesis.

A longitudinal Raman microspectroscopic study of osteoporosis induced by spinal cord injury

INTRODUCTION

A longitudinal study was established to investigate bone compositional information in spinal cord injury (SCI) rat model.

METHODS

Raman spectroscopy was applied to detect the distal femur and humeri of SCI, sham-operated (SO), and age-matched control (CON) male Sprague-Dawley (SD) rats at first, second, third, and fifth weeks after surgery. One-way ANOVA and Tukey's HSD post hoc multiple comparison tests were used to analyze the longitudinal data of mineral to matrix ratio and carbonate substitution.

RESULTS

Relative mineral decrease was found in SCI group by more than 20% in femur and approximately 12% in humeri compared with CON group. No significant changes in carbonate substitution were observed.

CONCLUSIONS

Severe bone loss in the early stage of SCI was confirmed by a continuous decrease of the mineral to collagen matrix ratio. The decrease in the humeri suggested hormone level variations might participate in the etiology of SCI-induced osteoporosis.

[Growth responses of belowground modules of Carex lasiocarpa to different water regimes and water experiences]

With seedling's transplanting experiment under different water levels, this paper studied the growth responses of belowground modules of Carex lasiocarpa to various water regimes and water experiences in Sanjiang Plain. The results showed that the belowground modules of C. lasiocarpa had significantly different responses to water regimes. At thriving stage, the length of rhizome and adventitious root decreased with increasing water level, and until later growth stage, the maximal value still appeared under drought condition. However, under dry-wet alternate condition, the length of rhizome and adventitious root increased most from thriving stage to the end, indicating that stable and lower water level could improve the growth of rhizome and adventitious root. The biomass of rhizome, adventitious root, and belowground part were maximal under dry-wet alternate condition at both growth stages. For those with different water experiences, the ones undergoing alternate condition in early growth season and then drought had maximal rhizome biomass, and the others under sustained alternate condition had maximal adventitious root and belowground biomass. More biomass was distributed to rhizome in the later growth season under various water regimes. The percentage of rhizome in total biomass was significantly higher under drought condition than under other water conditions through the growth season. Besides, C. lasiocarpa grew slowly when submerged, but could recover through rhizomatic reproduction after the stress disappeared.

First-principles study: size-dependent optical properties for semiconducting silicon carbide nanotubes

Using first-principles calculations, we investigate the effect of tube size on optical properties of the zigzag, armchair, and chiral SiC nanotubes. The results indicate that the optical spectra of SiC nanotubes are dependent on the diameter and chirality, and that optical anisotropy is observed for different light polarizations. For a given chirality of SiCNTs, redshifts or blueshifts of the peaks in the dielectric function and energy loss function with increasing tube diameter are possible due to the competition between the size effect and pi orbitals overlapping, and the shifts become smaller as the tube diameter increases. The unusual optical properties of semiconducting SiC nanotubes present an opportunity for applications in electro-optical devices.

Clonal spread of SCCmec type IV methicillin-resistant Staphylococcus aureus between community and hospital

The staphylococcal chromosome cassette (SCC)mec types of 382 hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) isolates in Taiwan were analysed over a 7-year period (1999-2005). There was an abrupt increase in SCCmec type IV in HA-MRSA during 2005. The molecular epidemiology of a subset (n = 69) of HA-MRSA isolates with SCCmec types III, IV or V was characterised and compared with that of community-acquired MRSA (CA-MRSA) (n = 26, collected during 2005). Pulsed-field gel electrophoresis revealed three major pulsotypes (A, B and C) and 15 minor clones. Pulsotypes B and C, which contained isolates carrying SCCmec types IV and V, respectively, included both CA-MRSA and HA-MRSA isolates. Among 24 toxin genes analysed, five genes had significant differential distribution between CA-MRSA and SCCmec type III HA-MRSA. Furthermore, among SCCmec type IV isolates, the seb gene was detected more commonly in HA-MRSA. Analysis of representative members of the three major pulsotypes by multilocus sequence typing revealed two sequence types (STs), namely ST239 (SCCmecIII) and ST59 (SCCmecIV or SCCmecV). This suggests that ST59:SCCmecIV, which is usually community-acquired, has become an important nosocomial pathogen in the hospital studied.

The potential therapeutic role of lymph node resection in epithelial ovarian cancer: a study of 13918 patients

The aim of the study is to determine the role of lymphadenectomy in advanced epithelial ovarian cancer. The data were obtained from the Surveillance, Epidemiology and End Results (SEER) program reported between 1988 and 2001. Kaplan–Meier estimates and Cox proportional hazards regression models were used for analysis. Of 13 918 women with stage III–IV epithelial ovarian cancer (median age: 64 years), 87.9% were Caucasian, 5.6% African Americans, and 4.4% Asians. A total of 4260 (30.6%) underwent lymph node dissections with a median number of six nodes reported. For all patients, a more extensive lymph node dissection (0, 1, 2–5, 6–10, 11–20, and >20 nodes) was associated with an improved 5-year disease-specific survival of 26.1, 35.2, 42.6, 48.4, 47.5, and 47.8%, respectively (P<0.001). Of the stage IIIC patients with nodal metastases, the extent of nodal resection (1, 2–5, 6–10, 11–20, and >20 nodes) was associated with improved survivals of 36.9, 45.0, 47.8, 48.7, and 51.1%, respectively (P=0.023). On multivariate analysis, the extent of lymph node dissection and number of positive nodes were significant independent prognosticators after adjusting for age, year at diagnosis, stage, and grade of disease. The extent of lymphadenectomy is associated with an improved disease-specific survival of women with advanced epithelial ovarian cancer.

Efficacy of omeprazole and amoxicillin with either clarithromycin or metronidazole on eradication of Helicobacter pylori in Chinese peptic ulcer patients

AIM: One-week triple therapy with proton pump inhibitors, clarithromycin and amoxicillin has recently been proposed as the first-line treatment for Helicobacter pylori (H pylori) infection; however, data regarding the effects of this regimen in China are scarce. The aim of this prospective and randomized study was to compare the efficacy of clarithromycin and metronidazole when they were combined with omeprazole and amoxicillin on eradication of H pylori and ulcer healing in Chinese peptic ulcer patients.

METHODS: A total of 103 subjects with H pylori-positive peptic ulcer were randomly divided into two groups, and accepted triple therapy with omeprazole 20 mg, amoxicillin 1000 mg and either clarithromycin 500 mg (OAC group, n = 58) or metronidazole 400 mg (OAM group, n = 45). All drugs were given twice daily for 7 d. Patients with active peptic ulcer were treated with omeprazole 20 mg daily for 2-4 wk after anti-H pylori therapy. Six to eight weeks after omeprazole therapy, all patients underwent endoscopies and four biopsies (two from the antrum and two others from the corpus of stomach) were taken for rapid urease test and histological analysis (with modified Giemsa staining) to examine H pylori. Successful eradication was defined as negative results from both examination methods.

RESULTS: One hundred patients completed the entire course of therapy and returned for follow-up. The eradication rate of H pylori for the per-protocol analysis was 89.3% (50/56) in OAC group and 84.1% (37/44) in OAM group. Based on the intention-to-treat analysis, the eradication rate of H pylori was 86.2% (50/58) in OAC group and 82.2% (37/45) in OAM group. There were no significant differences in eradication rates between the two groups on either analysis. The active ulcer-healing rate was 96.7% (29/30) in OAC group and 100% (21/21) in OAM group (per-protocol analysis, P>0.05). Six patients in OAC group (10.3%) and five in OAM group (11.1%) reported adverse events (P>0.05).

CONCLUSION: One-week triple therapy with omeprazole and amoxicillin in combination with either clarithromycin or metronidazole is effective for the eradication of H pylori. The therapeutic regimen comprising metronidazole with low cost, good compliance and mild adverse events may offer a good choice for the treatment of peptic ulcers associated with H pylori infection in China.

The impact of intraoperative transoesophageal echocardiography on an unselected cardiac surgical population: a review of 2343 cases

Although intraoperative transoesophageal echocardiography (TOE) has an established role in the management of some cardiac surgical procedures, there is little data on its impact on coronary artery bypass graft (CABG) cases that are stratified for clinical risk. This is a retrospective review of the surgical impact of intraoperative TOE on 2,343 unselected cardiac cases. The surgical impact of TOE findings were rated E (essential)--resulted in changes to the proposed surgical procedure or V (valuable)--the surgical technique for the planned surgery was altered. The surgical impact that routine TOE had on low-, medium- and high-risk CABG cases was also examined. The surgical impact of TOE for the total study population (E + V) was 4.5%. The impact was greatest in combined CABG + mitral valve procedures (18%). The impact in CABG cases was 3.5% overall, with an estimated impact in low-risk patients of 2.8% (95% CI. 2.7-3.0%) versus 6.7% (95% CI. 5.9-7.7%) in high-risk cases. The commonest E-impact in CABG patients was unscheduled valve surgery (2.6% of high-risk patients). The complication rate attributable to TOE was 0.09%. These findings provide indirect evidence for a potential patient benefit from the routine use of TOE in cardiac surgery.

[Spectral study on five complexes derived from D-glucosamine and their effect on DNA]

Complexes CuGlu, ZnGlu, NiGlu, Fe(III) Glu, Co(III) Glu where Glu is d-glucosamine have been synthesized. The effects of these compounds on DNA have been studied by the UV-Vis, fluorescence and SERS methods. The possible active ways of these complexes with DNA have been discussed. The results show that the adsorbed state of these complexes on silver sols are similar, and that CuGlu, Co(III) Glu have strong interactions with DNA. Their acting ways on DNA are different. It is worth to do a further research on these compounds as anticancer drugs.

Expression of cysteine sulfinate decarboxylase mRNA in rat mammary gland

Our previous report demonstrated that high concentration of taurine is present in rat milk for the first few days of lactation and plays an important role in the body growth of rat pups. In the present study, gene expression of rate-limiting enzyme for taurine biosynthesis, cysteine sulfinate decarboxylase (CSD) were examined in rat mammary gland. By RT-PCR, CSD mRNA was found to be expressed in rat mammary gland like that in the liver. The expression level of CSD mRNA in the mammary gland was higher in the earlier lactational stage (days 1 and 6 of lactation) than that in the later lactational stage (day 14). CSD mRNA expression in the mammary gland of non-pregnant rats was only a trace level. By in situ hybridization analysis, CSD mRNA was demonstrated in the epithelial cells of the mammary gland. These results suggest that high concentrations of taurine in the milk are at least partially resulted from de novo synthesis of taurine in mammary gland epithelial cells and that the expression pattern of CSD mRNA may be responsible for the changes in taurine levels in the milk during a lactational period.

Effect of taurine in rat milk on the growth of offspring

The physiological significance of taurine in milk in the growth of rat pups was investigated. Our results confirmed that taurine was at an exceptionally high concentration in rat milk during the lactational period, especially for the first few days after birth. Pups taking no milk from natural dams but from foster mothers at an advanced lactational period showed a slower growth rate. Intraperitoneal administration of taurine to the foster mothers in the first five days restored this growth retardation. On the other hand, intraperitoneal administration of beta-alanine, a transport antagonist of taurine, to the natural dams through the lactational period induced a slower growth rate of pups. This beta-alanine treatment to dams increased beta-alanine concentration, but did not decrease taurine concentrations in milk, and serum taurine concentration in the pups receiving this milk was elevated. Direct administration of beta-alanine to pups also increased the serum taurine concentrations dose-dependently. Beta-alanine administration to pups significantly decreased [3H]taurine incorporation into all the organs examined, and in contrast. [3H]taurine concentrations in serum and urine were elevated. Thus, beta-alanine inhibited taurine incorporation into cells and accelerated taurine excretion into either urine or milk. Serum IGF-I levels in pups receiving beta-alanine either directly or via their mothers was significantly lower than those in control pups. Cumulatively, taurine ingestion from milk at an early lactational period seems critical for normal growth of rat neonates due to its role in maintaining normal serum IGF-I levels.

Error, bias, and long-branch attraction in data for two chloroplast photosystem genes in seed plants

Sequences of two chloroplast photosystem genes, psaA and psbB, together comprising about 3,500 bp, were obtained for all five major groups of extant seed plants and several outgroups among other vascular plants. Strongly supported, but significantly conflicting, phylogenetic signals were obtained in parsimony analyses from partitions of the data into first and second codon positions versus third positions. In the former, both genes agreed on a monophyletic gymnosperms, with Gnetales closely related to certain conifers. In the latter, Gnetales are inferred to be the sister group of all other seed plants, with gymnosperms paraphyletic. None of the data supported the modern "anthophyte hypothesis," which places Gnetales as the sister group of flowering plants. A series of simulation studies were undertaken to examine the error rate for parsimony inference. Three kinds of errors were examined: random error, systematic bias (both properties of finite data sets), and statistical inconsistency owing to long-branch attraction (an asymptotic property). Parsimony reconstructions were extremely biased for third-position data for psbB. Regardless of the true underlying tree, a tree in which Gnetales are sister to all other seed plants was likely to be reconstructed for these data. None of the combinations of genes or partitions permits the anthophyte tree to be reconstructed with high probability. Simulations of progressively larger data sets indicate the existence of long-branch attraction (statistical inconsistency) for third-position psbB data if either the anthophyte tree or the gymnosperm tree is correct. This is also true for the anthophyte tree using either psaA third positions or psbB first and second positions. A factor contributing to bias and inconsistency is extremely short branches at the base of the seed plant radiation, coupled with extremely high rates in Gnetales and nonseed plant outgroups.

Phylogenetic systematics of the tribe Millettieae (Leguminosae) based on chloroplast trnK/matK sequences and its implications for evolutionary patterns in Papilionoideae

Phylogenetic relationships in the tribe Millettieae and allies in the subfamily Papilionoideae (Leguminosae) were reconstructed from chloroplast trnK/matK sequences. Sixty-two accessions representing 57 traditionally recognized genera of Papilionoideae were sampled, including 27 samples from Millettieae. Phylogenies were constructed using maximum parsimony and are well resolved and supported by high bootstrap values. A well-supported "core Millettieae" clade is recognized, comprising the four large genera Millettia, Lonchocarpus, Derris, and Tephrosia. Several other small genera of Millettieae are not in the core Millettieae clade. Platycyamus is grouped with Phaseoleae (in part). Ostryocarpus, Austrosteenisia, and Dalbergiella are neither in the core Millettieae or Phaseoleae clade. These taxa, along with core Millettieae and Phaseoleae, form a monophyletic sister group to Indigofereae. Cyclolobium and Poecilanthe are close to Brongniartieae. Callerya and Wisteria belong to a large clade that includes all the legumes that lack the inverted repeat in their chloroplast genome, which confirms previous rbcL and phytochrome gene family phylogenies. The evolutionary history of four characters was examined in Millettieae and allies: the presence of canavanine, inflorescence types, the dehiscence of pods, and the presence of winged pods. trnK/matK sequence analysis suggests that the presence of a pseudoraceme or pseudopanicle and the accumulation of nonprotein amino acids are phylogenetically informative for Millettieae and allies with only a few exceptions.

Isolation and characterization of plasmid pSW200 from Erwinia stewartii

The nucleotide sequence of pSW200 of Erwinia stewartii SW2 was determined. This plasmid is 4367 bp long, consisting of four mobilization genes, mobCABD, and an origin of replication homologous to those of ColE1-type plasmids. The plasmid also contains a region of forty-one 15-bp repeats. Deleting this region does not affect the stability or the copy number when maintained as sole plasmid in the cell. However, the plasmid is rapidly lost when a homoplasmid with the intact repeat region is introduced into the cell. The function of this region may provide pSW200 an advantage in competing with an incompatible plasmid in the cell.

Glucocorticoid receptor phosphorylation: overview, function and cell cycle-dependence

All steroid hormone receptors are phosphorylated and undergo hormone-induced hyperphosphorylation. Most phosphorylated residues identified so far are serines in the N-terminal domain. Other residues and domains may also be phosphorylated, e.g. the estrogen receptor is phosphorylated on tyrosine in the hormone-binding domain. Many sites lie in consensus sequences for proline-directed, cell cycle-associated kinases. In some receptors hyperphosphorylation is induced by hormone antagonists as well as agonists, and leads to new phosphorylated sites. With glucocorticoid receptors, hyperphosphorylation is specific for glucocorticoid agonists, follows receptor activation and produces no new sites. Rate studies suggest that hyperphosphorylation is due to accelerated phosphorylation rather than delayed dephosphorylation. Evidence to date indicates that steroid hormone receptor phosphorylation serves not as an on-off switch but modulates function more subtly. Mutations of phosphorylated sites to alanine have been found to decrease activity by 0 to 90%, depending on mutated site, cell type, reporter gene and hormone concentration. With glucocorticoid receptors, some alanine mutants are up to 75% less active in hormone-induced transactivation of certain reporter genes. They are also inactive in hormone-induced repression of transcription of their own gene and down regulation of the receptor protein. Furthermore, they are much less sensitive to degradation. Both basal phosphorylation and hormone-dependent hyperphosphorylation of these receptors are cell cycle-dependent, basal phosphorylation being low in S phase and high in G2/M and hyperphosphorylation the reverse, suggesting a causal relation to the cell cycle-dependence of glucocorticoid activity reported with several cell lines. Hyperphosphorylation appears to be regulated by basal phosphorylation through negative charge in the N-terminal domain, which in S phase is relatively low and permits hyperphosphorylation, but in G2/M is relatively high and blocks hyperphosphorylation.

Control by basal phosphorylation of cell cycle-dependent, hormone-induced glucocorticoid receptor hyperphosphorylation

Mouse glucocorticoid receptors (GRs) are phosphorylated in the N-terminal domain at serine/ threonine residues, most lying in consensus sequences for cell cycle-associated kinases. Glucocorticoid agonists, but not antagonists, induce hyperphosphorylation. Phosphorylation of GRs overexpressed in Chinese hamster ovary (CHO) cells is cell cycle-dependent: basal phosphorylation in S phase is one third that in G2/M; glucocorticoids induce hyperphosphorylation in S but not G2/M, paralleling the reported sensitivity in S and resistance in G2/M of proliferating cells to transcriptional activation by glucocorticoids. This parallel led us to investigate what controls hyperphosphorylation. We tested three hypotheses: hyperphosphorylation is controlled by 1) negative charge due to basal GR phosphorylation, being permitted in S by low charge and blocked in G2/M by high charge; 2) presence in S and absence in G2/M of required kinases; 3) availability in S and lack in G2/M of unoccupied phosphorylatable sites. Our results are inconsistent with 2) and 3), but strongly support 1). GR mutants with alanines (A7GR) or glutamates (E7GR) replacing all but one phosphorylated site were overexpressed in CHO cells. Serine 122 remained intact to report GR phosphorylation. Consistent with hypothesis 1, with A7GRs hormone-induced hyperphosphorylation occurred in both S and G2/M (thus revealing kinase activity for hyperphosphorylation of at least serine 122 in both phases), whereas with E7GRs it occurred in neither phase. We conclude that basal GR phosphorylation controls hormone-induced GR hyperphosphorylation by modulating negative charge in the N-terminal domain and could potentially control other cell cycle-dependent GR properties.

Hormone-induced hyperphosphorylation of specific phosphorylated sites in the mouse glucocorticoid receptor

The glucocorticoid receptor (GR) is phosphorylated in its basal state, and rapidly undergoes hormone-induced hyperphosphorylation after binding glucocorticoids. Previously, we have identified seven phosphorylated sites in the mouse GR. Most of the sites are located in the regions of the N-terminal domain that are necessary for maximum transcriptional activity and reduce nonspecific binding to DNA. Using WCL2 cells, which overexpress mouse GRs, we now quantitate hormone-induced hyperphosphorylation at each of these sites. Addition of triamcinolone acetonide to WCL2 cells results in significant hyperphosphorylation at the majority of the sites. The hyperphosphorylation ratio, i.e. the 32P incorporation into GRs from hormone-treated cells divided by 32P incorporation into GRs from untreated cells, was above 1.0 for all sites but serine 150 and threonine 159. Serine 220 displays marked hormone dependence, with a ratio of 3. For most sites the ratio was about 1.5. Hormone-induced hyperphosphorylation not only increases the charge at selected phosphorylated sites but also provides a substantial increase in the overall negative charge around the region of the N-terminal domain that is involved in transactivation.

Cell cycle-dependent glucocorticoid receptor phosphorylation and activity

Proliferating cells display striking cell cycle dependence in sensitivity to gene activation by glucocorticoids; they are sensitive in late gap 1/synthesis (G1/S) (late G1 and S phases) but resistant in gap 2/mitotic (G2/M). Here we describe large cell cycle-dependent variations in glucocorticoid receptor (GR) phosphorylation that accompany, and may account for, the changes in sensitivity. GRs are basally phosphorylated and undergo hyperphosphorylation after hormone-induced activation. Identified phosphorylated sites are all in the N-terminal domain. Several lie in a region required for full transactivating activity and reduction of nonspecific binding to DNA. Most are in consensus sequences for cell cycle-associated kinases, suggesting that such kinases phosphorylate GRs. We now show with WCL2 cells (Chinese hamster ovary cells with overexpressed GRs) that: 1) glucocorticoid treatment fails to hyperphosphorylate GRs in G2/M but doubles phosphorylation in S, more than seen with unsynchronized cells; and 2) basal GR phosphorylation is almost three times higher in G2/M than S. These results, along with earlier observations, implicate GR phosphorylation with mechanisms of glucocorticoid resistance in G2/M. Such mechanisms might underlie some forms of glucocorticoid resistance in inflammatory and lymphoproliferative diseases. HPLC phosphopeptide maps of GRs from S and G2/M reveal no significant qualitative differences in phosphorylated sites, consistent with a general increase during G2/M in negative charge of the N-terminal domain. We also show that the previously described increase in GR hormone-binding capacity from G1 to S is accompanied by a parallel increase in GR protein.

Glucocorticoid receptors in ATP-depleted cells. Dephosphorylation, loss of hormone binding, HSP90 dissociation, and ATP-dependent cycling

Dependence of hormone binding to glucocorticoid receptors (GRs) on cellular ATP levels suggested that GRs traverse an ATP-dependent cycle, and without ATP accumulate in forms that cannot bind hormone. Such "null" receptors (NRs) were identified in ATP-depleted WEHI-7 cells, where they are tightly associated with the nuclear fraction and partly dephosphorylated. With WCL2 cells (Chinese hamster ovary cells with overexpressed GRs) depleted of ATP with azide, we have now identified dephosphorylated sites on NRs, studied possible roles of phosphorylation using GR mutants, and measured association with the 90-kDa heat shock protein (hsp90). Most NRs in WCL2 cells are dephosphorylated at serines 220 and 234, but GRs with those serines mutated to alanines do not resemble NRs since they bind hormone. They do not associate strongly with nuclei. On azide treatment, however, mutated GRs lose hormone binding capacity faster than normal GRs. Association of hsp90 (and presumably other heat shock proteins) with cytosolic GRs is drastically reduced by azide treatment, sufficient to account for decreased hormone binding. We conclude that: (a) dephosphorylation of GRs does not yield NRs, but may weaken association with hsp90. (b) The postulated ATP-dependent GR cycle can be accounted for by dissociation, and ATP-dependent reconstitution, of GR-hsp90 complexes. (c) ATP depletion blocks reconstitution of complexes. Uncomplexed GRs may accumulate as one form of NR; they are probably also the precursors for other forms of NR.

Glucocorticoid receptors: ATP-dependent cycling and hormone-dependent hyperphosphorylation

The dependence of hormone binding to glucocorticoid receptors (GRs) on cellular ATP levels led us to propose that GRs normally traverse an ATP-dependent cycle, possibly involving receptor phosphorylation, and that without ATP they accumulate in a form that cannot bind hormone. We identified such a form, the null receptor, in ATP-depleted cells. GRs are basally phosphorylated, and become hyperphosphorylated after treatment with hormone (but not RU486). In mouse receptors we have identified 7 phosphorylated sites, all in the N-terminal domain. Most are on serines and lie within a transactivation region. The time-course of hormone-induced hyperphosphorylation indicates that the primary substrates for hyperphosphorylation are the activated receptors; unliganded and hormone-liganded nonactivated receptors become hyperphosphorylated more slowly. After dissociation of substrates for hyperphosphorylation are the activated receptors; unliganded and hormone-liganded nonactivated receptors become hyperphosphorylated more slowly. After dissociation of hormone, most receptors appear to be recycled and reutilized in hyperphosphorylated form. From these and related observations, we have concluded that the postulated ATP-dependent cycle can be accounted for by hormone-induced or spontaneous dissociation of receptor-Hsp90 complexes, followed by reassociation of unliganded receptors with Hsp90 via an ATP-dependent reaction like that demonstrated in cell-free systems. Other steroid hormone receptors might traverse a similar cycle. Four of the 7 phosphorylated sites in the N-terminal domain are in consensus sequences for p34cdc2 kinases important in cell cycle regulation. This observation, along with the known cell cycle-dependence of sensitivity to glucocorticoids and other evidence, point to a role for receptor phosphorylation in controlling responses to glucocorticoids through the cell cycle.

Functional analyses of albumin expression in a series of hepatocyte cell lines and in primary hepatocytes

A series of simian virus 40-immortalized hepatocyte cell lines which are heterogeneous with regard to expression of albumin protein and RNA were characterized for their ability to transcribe the albumin gene. Nascent chain extension assay showed that albumin RNA levels in these cells were determined predominantly at the transcription level. The albumin promoter and enhancer sequences were fused to the bacterial chloramphenicol acetyltransferase gene; the ability of the resulting expression constructs to drive chloramphenicol acetyltransferase expression after transfection into these hepatocyte cell lines was measured. The activity of the albumin promoter and enhancer constructs in primary hepatocytes was also measured. The albumin promoter was expressed differentially in these cells; however, no correlation was found between the transcriptional efficiency of the transfected albumin promoter and endogenous albumin transcription. The albumin enhancer was functional in some but not all albumin-positive cells. The minimal albumin enhancer was mapped to a 330-base pair fragment extending from -9.94 kilobases (kb) to -10.27 kb; three elements within this fragment recently shown to be necessary for enhancer function in a murine hepatocyte cell line were also essential for albumin enhancer function in the rat hepatocyte cell line CWSV1. A transcriptional silencer was identified which could suppress the expression of the homologous albumin promoter and the heterologous herpes simplex virus thymidine kinase promoter. Preliminary analysis localized the albumin silencer between -11 and -12 kb. Our results suggest that multiple regulatory sequences may act cooperatively to determine efficient tissue-specific expression of the albumin gene.

Differing activities of medullary respiratory neurons in eupnea and gasping

Our purpose was to compare further eupneic ventilatory activity with that of gasping. Decerebrate, paralyzed, and ventilated cats were used; the vagi were sectioned within the thorax caudal to the laryngeal branches. Activities of the phrenic nerve and medullary respiratory neurons were recorded. Antidromic invasion was used to define bulbospinal, laryngeal, or not antidromically activated units. The ventilatory pattern was reversibly altered to gasping by exposure to 1% carbon monoxide in air. In eupnea, activities of inspiratory neurons commenced at various times during inspiration, and for most the discharge frequency gradually increased. In gasping, the peak discharge frequency of inspiratory neurons was unaltered. However, all commenced activities at the start of the phrenic burst and reached peak discharge almost immediately. The discharge frequencies of all groups of expiratory neurons fell in gasping, with many neurons ceasing activity entirely. These data are consistent with the hypothesis that brain stem mechanisms controlling eupnea and gasping differ fundamentally.

Activities of two new antiviral agents against guinea pig lymphotropic herpesvirus infection in vitro

Two new antiviral agents, compound 164, also known as 2'-nor-cGMP (9-[(2-hydroxy-1,3,2-dioxaphosphorinan-5-yl)oxymethyl]-guani ne P-oxide), and compound 102 [4-amino-5-bromo-7-(2-hydroxyethoxymethyl)-pyrrolo(2,3-d)pyrimidine], together with acyclovir for comparison, were evaluated for activities against the guinea pig lymphotropic herpesvirus infection in vitro by plaque reduction and virus yield reduction assays in guinea pig embryo cells. The two new compounds were demonstrated to be more potent against guinea pig lymphotropic herpesvirus infections than acyclovir. Compound 164 was the most potent of the three; drug concentrations required to reduce the number of plaques by 50% were 2, 35.5, and 144.5 microM for compounds 164, 102, and acyclovir, respectively. The two new compounds were cytostatic but not cytotoxic to guinea pig embryo cells in cultures. Attempts were made to investigate the inhibition of viral replication by these compounds, and the influence of test conditions on antiviral evaluations is discussed.

Evaluation of new antiviral agents: I. In vitro perspectives

A variety of different methods for the evaluation of antiviral agents in cell culture systems are briefly reviewed. It has been repeatedly noted that many test conditions such as the cell culture system, virus strain, virus challenge dose, virus input multiplicity of infection, and time of harvesting, etc., can substantially affect or even alter the test results, thus making comparative studies and unambiguous evaluations very difficult. Attempts are made to discuss previous test methods together with our recent studies with the aim to simplify test procedures and assay methods. Suggestions are proposed for in vitro evaluation of new antiviral agents. It is hoped that this review will alarm investigators to the problems of assaying new antiviral agents. If the suggestions made in this review can be followed, the screening of the enormous number of promising antiviral compounds may be made more efficiently in the near future.

[Studies on the origin of different discharge pattern of the two types of phrenic motoneurones by cross-correlation analysis]

Experiments were performed on twenty five anesthetized, paralyzed, vagotomized and artificially ventilated rabbits. Discharges of single phrenic nerve fibers were recorded. According to their discharge patterns, phrenic motoneurones were divided into two types: tonic units (TU) and phasic units (PU). A cross-correlation analysis was done between TU and TU, PU and PU, or TU and PU. In 21/36 pairs of phrenic motoneurones, the cross-correlation histogram showed a significant central peak, which represented synchronization of the pair of units resulting from a common input. There were three types of synchronization: short-term, broad peak and high frequency-oscillatory synchronization. The difference in synchronization number between heterogeneous pairs (1 TU and 1PU, 2/10 showing synchronization) and homogeneous pairs (2 TU or 2 PU, 19/26 showing synchronization) was statistically significant (x2-test, P less than 0.05). These results suggest that TU and PU have different central inputs, which result in their different discharge patterns between the TU and PU.

Metal-binding abilities of radioprotective aminoalkyl disulfides and thiosulfates

Mental-binding stability constants for several heterocyclic aminoalkyl disulfides and thiosulfates with Ni(II) and Al(III) were determined. The data obtained indicated that both classes of compounds were acting as bidentate chelating agents and that the heterocyclic rings apparently prevented tridentate behavior of the disulfides because of steric hindrance. The magnitude of the constants indicated that metal complexes of these compounds could exist in a cellular environment, but no correlation with radiation-protective activity was apparent.

A facile method of purification of neocarzinostatin, an antitumor protein

A three-step column chromatographic method for the purification of neocarzinostatin (NCS) from a crude preparation was described. The purified material was homogeneous by acrylamide gel electrophoresis, isoelectric focusing, amino terminal analysis, and immunologic criteria. Purified NCS was 40 times as active in the inhibition of growth of Sarcina lutea and twice as active against CCRF-CEM human leukemia cells in vitro as was the starting material. When assayed against P388 and L1210 mouse leukemias in vivo, the purified material showed a median increase in life-span of 119 and 72%, respectively.