Methylomonas defluvii sp. nov., a type I methane-oxidizing bacterium from a secondary sedimentation tank of a wastewater treatment plant

An aerobic methanotroph was isolated from a secondary sedimentation tank of a wastewater treatment plant and designated strain OY6T. Cells of OY6T were Gram-stain-negative, pink-pigmented, motile rods and contained an intracytoplasmic membrane structure typical of type I methanotrophs. OY6T could grow at a pH range of 4.5-7.5 (optimum pH 6.5) and at temperatures ranging from 20 °C to 37 °C (optimum 30 °C). The major cellular fatty acids were C14 : 0, C16 : 1ω7c/C16 : 1ω6c and C16 : 1ω5c; the predominant respiratory quinone was MQ-8. The genome size was 5.41 Mbp with a DNA G+C content of 51.7 mol%. OY6T represents a member of the family Methylococcaceae of the class Gammaproteobacteria and displayed 95.74-99.64 % 16S rRNA gene sequence similarity to the type strains of species of the genus Methylomonas. Whole-genome comparisons based on average nucleotide identity (ANI) and digital DNA-DNA hybridisation (dDDH) confirmed that OY6T should be classified as representing a novel species. The most closely related type strain was Methylomonas fluvii EbBT, with 16S rRNA gene sequence similarity, ANI by blast (ANIb), ANI by MUMmer (ANIm) and dDDH values of 99.64, 90.46, 91.92 and 44.5 %, respectively. OY6T possessed genes encoding both the particulate methane monooxygenase enzyme and the soluble methane monooxygenase enzyme. It grew only on methane or methanol as carbon sources. On the basis of phenotypic, genetic and phylogenetic data, strain OY6T represents a novel species within the genus Methylomonas for which the name Methylomonas defluvii sp. nov. is proposed, with strain OY6T (=GDMCC 1.4114T=KCTC 8159T=LMG 33371T) as the type strain.

[Analysis on personal protection in occupational population at high risk for brucellosis and influencing factor in China]

Objective: To understand the current status of personal protection in occupational population at high risk for brucellosis in China and provide evidence for the evaluation of implementation of National Brucellosis Prevention and Control Plan (2016-2020). Methods: Four counties in Shanxi Province and Xinjiang Uygur Autonomous Region were selected to conduct a questionnaire survey in occupational population at high risk for brucellosis from December 2019 to July 2020 by using cross-sectional survey methods. Results: A total of 2 384 persons at high risk for brucellosis were surveyed, and the standardized utilization rate of personal protective equipment (PPE) was 20.13% (480/2 384). The utilization rate of glove, mask, rubber shoe, and work cloth were 38.26% (912/2 384), 31.80% (758/2 384), 32.01% (763/2 384) and 30.87% (736/2 384),respectively. There were significant differences in the utilization rate and standardized utilization rate of the four types of PPE among populations in different age, occupation, educational level and area groups (all P<0.001). The utilization rate and standardized utilization rate of PPE were lower in people over 60 years old, women, farmers, and those with lower educational level. The results of multivariate analysis showed that occupation and area were the influencing factors for the standardized utilization of PPE, the standardized utilization rates of PPE were higher in herdsmen and veterinarians. The standardized utilization rate of PPE in Yanggao County and Huocheng County was significantly higher than that in Zuoyun County and Hunyuan County. Conclusions: The utilization rate of the four types of PPE in occupational population at high risk for brucellosis was not high in China, and the standardized utilization rate was low, lower than the requirement in National Brucellosis Prevention and Control Plan, and there were significant differences among different areas. It is urgent to distribute PPE to occupational population at high risk for brucellosis and carry out health education about PPE utilization. Meanwhile, it is necessary to strengthen information exchange or sharing among different areas.

[Analysis of fast-growing culturable bacteria and pathogenic bacteria in the surface water of the northeast coast of Hainan Island in China]

Objective: To obtain the diversity and abundance of fast-growing bacteria in the surface water of the northeast coast of Hainan Island in China, different cultivation methods were employed. This study also aims to provide a reference for isolating bacterial samples from seawater sources and preventing marine-derived pathogens. Methods: Based on the principles of taxonomic design, surface seawater samples were collected from six locations along the northeast coast of Hainan Island in China in March, June, October, and December 2021. Then, bacterial enrichment was performed based on traditional cultivation methods for Salmonella, Vibrio, Burkholderia pseudomallei, Actinomycetes, and general marine bacteria. After that, bacterial species identification was conducted by 16S rDNA amplicon sequencing and metagenomic sequencing. Results: A total of 1 151 fast-growing cultivable bacteria belonging to 66 genera and 213 species were identified using five different culture protocols. In different cultivation protocols, Bacillus and Klebsiella demonstrated extensive discriminatory advantages and ranked among the top genera in terms of abundance. Protocol 1 had Escherichia, Klebsiella, and Citrobacter as dominant genera. Pathogenic bacteria detected by protocol 1 included Klebsiella pneumoniae and Escherichia coli, with 37 and 29 strains respectively, while Salmonella enterica was uniquely detected with seven isolates. Proteus, Enterococcus, and Providencia were the dominant genera in protocol 2, and Proteus mirabilis was the most abundant pathogenic bacteria detected with 66 isolates. Vibrio cholerae was uniquely detected with six isolates at a higher abundance. Klebsiella, Escherichia, and Acinetobacter were the dominant genera in protocol 3, and Klebsiella pneumoniae was the most abundant pathogenic bacteria detected with 53 isolates, while Acinetobacter nosocomialis was uniquely detected with seven isolates. Vibrio and Pseudoalteromonas were the dominant genera in protocol 4, and they showed advantages in isolating and cultivating Marine-derived Vibrio. Exiguobacterium, Staphylococcus, and Bacillus were the dominant genera in protocol 5. Bacillus cereus and Lactococcus lactis were the most abundant pathogenic bacteria detected with 20 and 15 isolates, respectively, while Lactococcus lactis was uniquely detected at higher abundance. Metagenomic sequencing showed that Klebsiella pneumoniae was significantly dominant with a gene abundance of 51.11%, followed by Alcanivorax sp. at 12.57%. Conclusion: The surface water of the northeast coast of Hainan Island in China exhibits a rich diversity of bacteria, with Klebsiella pneumoniae being highly abundant in the studied area. Different cultivation methods demonstrate distinct selective advantages in culturing bacterial genera and pathogens. Therefore, it is necessary to optimize cultivation conditions for specific marine bacteria.

Electroacupuncture prevents astrocyte atrophy to alleviate depression

Astrocyte atrophy is the main histopathological hallmark of major depressive disorder (MDD) in humans and in animal models of depression. Here we show that electroacupuncture prevents astrocyte atrophy in the prefrontal cortex and alleviates depressive-like behaviour in mice subjected to chronic unpredictable mild stress (CUMS). Treatment of mice with CUMS induced depressive-like phenotypes as confirmed by sucrose preference test, tail suspension test, and forced swimming test. These behavioural changes were paralleled with morphological atrophy of astrocytes in the prefrontal cortex, revealed by analysis of 3D reconstructions of confocal Z-stack images of mCherry expressing astrocytes. This morphological atrophy was accompanied by a decrease in the expression of cytoskeletal linker Ezrin, associated with formation of astrocytic leaflets, which form astroglial synaptic cradle. Electroacupuncture at the acupoint ST36, as well as treatment with anti-depressant fluoxetine, prevented depressive-like behaviours, astrocytic atrophy, and down-regulation of astrocytic ezrin. In conclusion, our data further strengthen the notion of a primary role of astrocytic atrophy in depression and reveal astrocytes as cellular target for electroacupuncture in treatment of depressive disorders.

[Assessment of intensity of seasonal influenza activity in Beijing-Tianjin-Hebei region, 2019-2021]

Objective: To explore the feasibility of moving epidemic method (MEM) in the assessment of seasonal influenza (influenza) activity intensity from the perspective of urban agglomeration, assess influenza activity intensity in the Beijing-Tianjin-Hebei region from 2019 to 2021 and evaluate the reliability of surveillance data and the effectiveness of the MEM model application. Methods: The weekly reported incidence rate (IR) of influenza and the percentage of influenza-like illness (ILI%) from 2011-2021 in Beijing-Tianjin-Hebei region were collected to establish MEM models respectively. The model fitting effect and the reliability of the two data were evaluated for the purpose of establishing an optimal model to assess the influenza activity intensity in Beijing-Tianjin-Hebei region from 2019-2021. A cross-validation procedure was used to evaluate the performance of the models by calculating the Youden's index, sensitivity and specificity. Results: The MEM model fitted with weekly ILI% had a higher Youden's index compared with the model fitted with weekly IR at both Beijing-Tianjin-Hebei region level and provincial level. The MEM model based on ILI% showed that the epidemic threshold in Beijing-Tianjin-Hebei region during 2019-2020 was 4.42%, the post-epidemic threshold was 4.66%, with medium, high and very high intensity thresholds as 5.38%, 7.22% and 7.84%, respectively. The influenza season during 2019-2020 had 10 weeks (week 50 of 2019 to week 7 of 2020). The influenza season started in week 50 of 2019, and the intensity fluctuated above and below medium epidemic level for six consecutive weeks. The high intensity was observed in week 4 of 2020, the threshold of very high intensity was excessed in week 5, and the intensity gradually declined and became lower than the threshold at the end of the influenza season in week 8. The epidemic threshold was 4.29% and the post-epidemic threshold was 4.35% during 2020-2021. Influenza activity level never excessed the epidemic threshold throughout the year, and no epidemic period emerged. Conclusions: The MEM model could be applied in the assessment of influenza activity intensity in Beijing-Tianjin-Hebei region, and the use of ILI% to assess influenza activity intensity in this region was more reliable than IR data. Influenza activity intensity in Beijing-Tianjin-Hebei region was higher during 2019-2020 but significantly lower in 2020-2021.

[Influence factors of poor efficacy after flap repair operation in patients with pressure ulcers]

Objective: To investigate the influence factors of poor efficacy after flap repair operation in patients with pressure ulcers. Methods: The retrospective case series study was conducted. From January 2011 to June 2021, 125 patients with stage Ⅲ and Ⅳ pressure ulcers treated in Hainan General Hospital met the inclusion criteria. There were 82 males and 43 females, aged 15-90 (57±20) years. According to the postoperative effects, the patients were divided into poor efficacy group (47 cases) and good efficacy group (78 cases). The clinical data of patients in the two groups were collected, including the age, gender, location, stage, size, and bone exposure of pressure ulcers, preoperative microorganism culture results of wound exudate sample, whether combined with osteomyelitis, diabetes, lower limb paroxysmal myospasm, and gatism or not, the number of surgical debridement combined with negative-pressure wound therapy, type of surgical flap, postoperative position, and preoperative albumin, leukocyte, C-reactive protein (CRP), and hemoglobin. Data were statistically analyzed with independent sample t test, Mann-Whitney U test, and chi-square test. The binary multivariate logistic regression analysis was conducted to screen the independent risk factors influencing the poor efficacy after flap repair operation in 125 patients with stage Ⅲ and Ⅳ pressure ulcers. Results: The ratio of patients with lower limb paroxysmal myospasm in poor efficacy group was 22/47, which was significantly higher than 3/78 in good efficacy group (χ2=33.83, P<0.01). The preoperative hemoglobin level of patients in poor efficacy group was (102±17) g/L, which was significantly lower than (113±20) g/L in good efficacy group (t=-3.24, P<0.01). The preoperative CRP level of patients was 39.1 (14.1, 91.6) mg/L in poor efficacy group, which was significantly higher than 15.3 (6.6, 42.0) mg/L in good efficacy group (Z=-3.04, P<0.01). There were no statistically significant differences in other indexes between patients in the two groups (P>0.05). Multivariate logistic regression analysis showed that age, lower limb paroxysmal myospasm, and preoperative hemoglobin level were the independent risk factors for poor efficacy after flap repair operation in patients with pressure ulcers (with odds ratios of 1.03, 40.69, and 0.97, 95% confidence intervals of 1.00-1.06, 9.18-180.39, and 0.95-1.00, respectively, P<0.05 or P<0.01). Conclusions: Poor efficacy after flap repair operation in patients with pressure ulcers is affected by many factors, among which the age, lower limb paroxysmal myospasm, and preoperative hemoglobin level are the independent risk factors.

Woman diagnosed with obsessive-compulsive disorder became delusional after childbirth: A case report

BACKGROUND

Obsessive-compulsive disorder (OCD) is a common mental disorder that varies greatly in manifestation and causes much distress to individuals. We describe a case in which a Chinese woman with OCD became delusional after childbirth, and discuss the possible phenomenological and psychological alterations.

CASE SUMMARY

A 27-year-old woman presented to the Psychiatry Department of our hospital with obsessions and compulsions. After taking medication, her symptoms were alleviated. Three years later, during her pregnancy, the obsessions returned and even progressed into paranoid delusions after childbirth. After multiple adjustments of treatment along with several fluctuations, she finally achieved remission and gained reasonable insight.

CONCLUSION

This case suggests that the patient with OCD appeared to move along a continuum of beliefs, and highlights the importance of effective intervention during pregnancy, which would exert a significant impact on postpartum exacerbation outcomes.

Interhemispheric functional connectivity for Alzheimer's disease and amnestic mild cognitive impairment based on the triple network model

The purpose of this study was to explore the differences in interhemispheric functional connectivity in patients with Alzheimer's disease (AD) and amnestic mild cognitive impairment (aMCI) based on a triple network model consisting of the default mode network (DMN), salience network (SN), and executive control network (ECN). The technique of voxel-mirrored homotopic connectivity (VMHC) analysis was applied to explore the aberrant connectivity of all patients. The results showed that: (1) the statistically significant connections of interhemispheric brain regions included DMN-related brain regions (i.e. precuneus, calcarine, fusiform, cuneus, lingual gyrus, temporal inferior gyrus, and hippocampus), SN-related brain regions (i.e. frontoinsular cortex), and ECN-related brain regions (i.e. frontal middle gyrus and frontal inferior); (2) the precuneus and frontal middle gyrus in the AD group exhibited lower VMHC values than those in the aMCI and healthy control (HC) groups, but no significant difference was observed between the aMCI and HC groups; and (3) significant correlations were found between peak VMHC results from the precuneus and Mini Mental State Examination (MMSE) and Montreal Cognitive Scale (MOCA) scores and their factor scores in the AD, aMCI, and AD plus aMCI groups, and between the results from the frontal middle gyrus and MOCA factor scores in the aMCI group. These findings indicated that impaired interhemispheric functional connectivity was observed in AD and could be a sensitive neuroimaging biomarker for AD. More specifically, the DMN was inhibited, while the SN and ECN were excited. VMHC results were correlated with MMSE and MOCA scores, highlighting that VMHC could be a sensitive neuroimaging biomarker for AD and the progression from aMCI to AD.

Salidroside protects PC-12 cells against amyloid β-induced apoptosis by activation of the ERK1/2 and AKT signaling pathways

Alzheimer’s disease (AD) is one of the most frequent diseases in elderly people and causes high mortality. Its incidence is increasing annually and no effective therapeutic treatment currently exists. In the present study, salidroside, a major active ingredient of Rhodiola rosea, was able to protect PC-12 cells from the toxicity and apoptosis induced by AD inducer amyloid (A)β_1--42. Salidroside significantly protected PC-12 cells by inhibiting Aβ_1-42-induced cytotoxicity and mitochondria-mediated endogenous caspase apoptotic pathways. Mechanistic studies demonstrated that salidroside significantly activated the extracellular signal regulated kinase (ERK)1/2 and protein kinase B (AKT) signaling pathways. This observation was further confirmed using the ERK1/2 inhibitor PD98059 and the AKT inhibitor LY294002, which demonstrated that salidroside promoted PC-12 cell survival and proliferation by activating the ERK1/2 and AKT signaling pathways. Salidroside is a therapeutic candidate for the treatment of AD and provides a basis for further drug development.

[Efficacy and tolerance of Memantine monotherapy and combination therapy with Reinhartdt And Sea Cucumber Capsule on agitation in moderate to severe Alzheimer disease]

Objective: To explore the efficacy and tolerance of Memantine combined Reinhartdt And Sea Cucumber Capsule (R.S.C) on treating agitation in patients with moderate-severe Alzheimer disease (AD). Methods: One hundred and fifty-eight moderate-sever AD patients from Sep.2013 to Sep.2014 in Zhejiang Provincial People's Hospital were randomly divided into two groups: group of Memantine combined R. S.C and group of single Memantine. Then Mini-Mental Sate Examination (MMSE) and Neuropsychiatric Inventory (NPI) were used to evaluate cognition symptom, behavioral and psychological symptoms of dementia (BPSD) and agitation symptom at the baseline and the end of 24 weeks.The Treatment Emergent Symptom Scale (TESS) was used to assess adverse reaction and tolerance.At last, the data was analyzed by chi-square test, t-test and covariance test. Result: At the terminal of experience, the total NPI scores and agitation factor decreased markedly in both of the two groups (P<0.05). Among the patients who had agitation symptom at the baseline, the total NPI scores and agitation factor (18±5, 3.7±2.6) in group of Memantine combined R. S.C were notably lower than those in the group of single Memantine (21±6, 5.3±2.5) (P<0.05). The incidence of adverse reaction between the two groups had no significant difference (combined treatment group was 27.7%, single treatment group was 23.2%). One patient dropped out because of skin allergy, and most adverse reactions were tolerant. Conclusions: Both two groups are effective in agitation and BPSD, and Memantine combined R. S.C is better than single treatment.R.S.C dose not aggravate adverse reaction and can be well tolerated.

Controlled Release of Vanadium from a Composite Scaffold Stimulates Mesenchymal Stem Cell Osteochondrogenesis

Large bone defects often require the use of autograft, allograft, or synthetic bone graft augmentation; however, these treatments can result in delayed osseous integration. A tissue engineering strategy would be the use of a scaffold that could promote the normal fracture healing process of endochondral ossification, where an intermediate cartilage phase is later transformed to bone. This study investigated vanadyl acetylacetonate (VAC), an insulin mimetic, combined with a fibrous composite scaffold, consisting of polycaprolactone with nanoparticles of hydroxyapatite and beta-tricalcium phosphate, as a potential bone tissue engineering scaffold. The differentiation of human mesenchymal stem cells (MSCs) was evaluated on 0.05 and 0.025 wt% VAC containing composite scaffolds (VAC composites) in vitro using three different induction media: osteogenic (OS), chondrogenic (CCM), and chondrogenic/osteogenic (C/O) media, which mimics endochondral ossification. The controlled release of VAC was achieved over 28 days for the VAC composites, where approximately 30% of the VAC was released over this period. MSCs cultured on the VAC composites in C/O media had increased alkaline phosphatase activity, osteocalcin production, and collagen synthesis over the composite scaffold without VAC. In addition, gene expressions for chondrogenesis (Sox9) and hypertrophic markers (VEGF, MMP-13, and collagen X) were the highest on VAC composites. Almost a 1000-fold increase in VEGF gene expression and VEGF formation, as indicated by immunostaining, was achieved for cells cultured on VAC composites in C/O media, suggesting VAC will promote angiogenesis in vivo. These results demonstrate the potential of VAC composite scaffolds in supporting endochondral ossification as a bone tissue engineering strategy.

[Analysis of myopia and axial length changes and relevant factors of children aged 7 to 14 years in Wenzhou]

OBJECTIVE

To investigate the incidence and features of myopia in children aged 7 to 14 years.

METHODS

Cross-sectional study. A total of 2 226 children (2 226 eyes) aged 7 to 14 years were selected from school during June 2012 and January 2015. Refraction was measured by fast cycloplegic retinoscopy. SPSS16.0 was used to analyze the data. Ocular refractive parameters, including axial length (AL), corneal power, anterior chamber depth, and white to white, were measured by IOLMaster (version 5.0, Carl Zeiss, Germany). Only the right eyes were included in the analysis.

RESULTS

(1) The incidence of myopia in children increased with age. The incidence of myopia in female children was higher than male children with the same age. The overall incidence of myopia in female children was higher than male children (χ(2)=4.284, P=0.036). The average AL was (23.53±1.12) mm in male children and (23.44±1.08) mm in female children, and there was no statistically significant difference (t=1.502, P=0.134). (2) The change of refractive parameters was as follows. The AL elongated with age ,the average AL located in (22.84±0.87) to (24.49±1.19) mm(F=10.076, P<0.001) . The anterior chamber became deepened with age,the average ACD located in (3.28±0.16) to (3.67±0.24) mm (F=8.059, P<0.001). The white to white reduced slightly with age, the average WTW located in (12.30 ± 0.35) to (12.16 ± 0.54) mm,although there was no significant difference (F=0.469, P=0.857). There was no difference in the corneal power with age ,the average corneal power located in (43.05±1.31) to (43.74±1.20) D(F=0.440, P=0.877). The values of AL, anterior chamber depth in the myopia group were greater than the emmetropia group with the same age (P<0.05). (3) Correlation factor analysis of AL was as follows. Mixed effects model displayed that the age, height, and body weight were related to eye axis. The regression equation of AL was: AL=19.120 4+0.124 2×A+0.019 6×H+ 0.015 3×W. The AL was positively correlated with the body height (r=0.527, P< 0.01) and weight (r=0.47, P< 0.01).

CONCLUSIONS

Among children aged 7 to 14 years, the incidence of myopia, AL, and anterior chamber depth increase with age. During the period of rapid physical development, the refraction and AL should be monitored. The prevalence of myopia is relatively high in girls, which may be associated with outdoor activity. (Chin J Ophthalmol, 2016, 52: 514-519).

[Polycyclic aromatic hydrocarbons exposure and birth defects]

Birth defects are one of the most common adverse birth outcomes, which create a heavy economic burden to the country, society and family. And they are also one of the biggest problems facing public health today. Polycyclic aromatic hydrocarbons (PAHs) are a group of toxic pollutants existing in the environment widely, resulting from incomplete organic matter combustion, and can be taken into the body through various ways including the digestive tract, respiratory tract and so on. Recent researches suggest that the exposure of PAHs may be associated with various birth defects, while the special mechanism isn't very clear. This paper is a review of the relationship between PAHs and birth defects from the aspects of epidemiological data, experimental evidence on animals, which indicates that exposure of PAHs during pregnancy may be associated with birth defects including congenital heart defects, neural tube defects and cleft lip/plate. Furthermore, we explored the possible mechanism, including oxidative stress, oxidative damage and the changes of signal transduction pathway in order to provide some recommendations and suggestions on the future work.

[Analysis of the influence factors of school-age children's refractive status]

Objective: To analyze the influence of the eye biological parameters, height, and weight on the school-age children's refractive status. Methods: Cross-sectional study. A total of 1 656 children (1 656 eyes), aged from 7 to 14 years, were selected from 8 schools in Wenzhou during June 2012 and June 2013. The height and weight of each child were measured, and the body mass index (BMI) was calculated. The eye biological parameters, including axial length (AL), corneal power (C=1/CR), anterior chamber depth (ACD), and white to white (WTW), were measured by IOLMaster (version 5.0, Carl Zeiss, Germany), and the AL/CR was calculated. Refraction was measured by fast cycloplegic retinoscopy, and the spherical equivalent (SE) was calculated. Only right eyes were included in the analysis. SPSS16.0 was used to analyze the data. The correlations of the equivalent spherical power, the eye biological parameters, height, weight, and BMI were evaluated. Linear regression analysis was used for the SE, AL, and AL/CR. Results: The prevalence of myopia in 7- to 14-year-old school-age children was 50.2% on the average, 48.4% in boys, and 51.7% in girls. The average SE was (-1.07±1.74) D. With adjustment of the age, gender, urban and rural areas, there was an association between the SE and AL, AL/CR, ACD, height and weight. The correlation coefficient was -0.663, -0.730, -0.416, -0.365, and -0.281, respectively (P<0.05). There was no significant correlation between the SE and WTW, corneal power and BMI. Regarding the different refractive statuses, there was a stronger correlation between the SE and AL, AL/CR in children with hyperopia, moderate myopia or high myopia than those with emmetropia or mild myopia (P< 0.01). In the older children, the correlation between the SE and AL, AL/CR was stronger. Linear regression analysis showed SE= 26.55-9.11·AL/CR and 23.0-1.02·AL. Conclusions: There was an association between the SE and AL, AL/CR, ACD, height and weight in school-age children. In children with hyperopia, moderate myopia, high myopia or at an older age, the correlation was more significant between the SE and AL, AL/CR. (Chin J Ophthalmol, 2016, 52:831-835).

Opening the band gap of graphene through silicon doping for the improved performance of graphene/GaAs heterojunction solar cells

Graphene has attracted increasing interest due to its remarkable properties. However, the zero band gap of monolayered graphene limits it's further electronic and optoelectronic applications. Herein, we have synthesized monolayered silicon-doped graphene (SiG) with large surface area using a chemical vapor deposition method. Raman and X-ray photoelectron spectroscopy measurements demonstrate that the silicon atoms are doped into graphene lattice at a doping level of 2.7-4.5 at%. Electrical measurements based on a field effect transistor indicate that the band gap of graphene has been opened via silicon doping without a clear degradation in carrier mobility, and the work function of SiG, deduced from ultraviolet photoelectron spectroscopy, was 0.13-0.25 eV larger than that of graphene. Moreover, when compared with the graphene/GaAs heterostructure, SiG/GaAs exhibits an enhanced performance. The performance of 3.4% silicon doped SiG/GaAs solar cell has been improved by 33.7% on average, which was attributed to the increased barrier height and improved interface quality. Our results suggest that silicon doping can effectively engineer the band gap of monolayered graphene and SiG has great potential in optoelectronic device applications.

Tunable deep-subwavelength superscattering using graphene monolayers

In this Letter, we theoretically propose for the first time that graphene monolayers can be used for superscatterer designs. We show that the scattering cross-section of the bare deep-subwavelength dielectric cylinder is markedly enhanced by six orders of magnitude due to the excitation of the first-order resonance of graphene plamons. By utilizing the tunability of the plasmonic resonance through tuning graphene's chemical potential, the graphene superscatterer works in a wide range of frequencies from several terahertz to tens of terahertz.

Negative thermal quenching of photoluminescence in zinc oxide nanowire-core/graphene-shell complexes

Graphene is an atomic thin two-dimensional semimetal whereas ZnO is a direct wide band gap semiconductor with a strong light-emitting ability. In this paper, we report on photoluminescence (PL) of ZnO-nanowires (NWs)-core/Graphene-shell heterostructures, which shows a negative thermal quenching (NTQ) behavior both for the near band-edge and deep level emission. The abnormal PL behavior was understood through the charging and discharging processes between ZnO NWs and graphene. The NTQ properties are most possibly induced by the unique rapidly increasing density of states of graphene as a function of Fermi level, which promises a higher quantum tunneling probability between graphene and ZnO at a raised temperature.

Phosphorus doped Zn(1-x)Mg(x)O nanowire arrays

We demonstrate the growth of phosphorus doped Zn(1-x)Mg(x)O nanowire (NW) using pulsed laser deposition. For the first time, p-type Zn(0.92)Mg(0.08)O:P NWs are likely obtained in reference to atomic force microscopy based piezoelectric output measurements, X-ray photoelectron spectroscopy, and the transport property between the NWs and a n-type ZnO film. A shallow acceptor level of approximately 140 meV is identified by temperature-dependent photoluminescence. A piezoelectric output of 60 mV on average has been received using the doped NWs. Besides a control on NW aspect ratio and density, band gap engineering has also been achieved by alloying with Mg to a content of x = 0.23. The alloyed NWs with controllable conductivity type have potential application in high-efficiency all-ZnO NWs based LED, high-output ZnO nanogenerator, and other optical or electrical devices.

Identifying individual n- and p-type ZnO nanowires by the output voltage sign of piezoelectric nanogenerator

Based on a comparative study between the piezoelectric outputs of n-type nanowires (NWs) and n-core/p-shell NWs along with the previous study (Lu et al 2009 Nano. Lett. 9 1223), we demonstrate a one-step technique for identifying the conductivity type of individual ZnO nanowires (NWs) based on the output of a piezoelectric nanogenerator without destroying the sample. A negative piezoelectric output voltage indicates an NW is n-type and it appears after the tip scans across the center of the NW, while a positive output voltage reveals p-type conductivity and it appears before the tip scans across the central line of the NW. This atomic force microscopy based technique is reliable for statistically mapping the majority carrier type in ZnO NWs arrays. The technique may also be applied to other wurtzite semiconductors, such as GaN, CdS and ZnS.

Chronic aspiration shifts the immune response from Th1 to Th2 in a murine model of asthma

BACKGROUND

Chronic aspiration associated with gastro oesophageal reflux disease (GERD) is thought to play a substantial role in the development of asthma, the incidence of which is dramatically increasing in industrially developed countries. The majority of data examining the association between aspiration and asthma has been obtained from epidemiological studies, which show that between 50 and 90% of individuals with asthma experience some element of GERD. This study describes the effect of chronic aspiration on a model of experimentally induced airway hypersensitivity in Balb/c mice.

MATERIALS AND METHODS

Four experimental groups were utilized: Aspiration/Asthma, Sham/Asthma, Aspiration/Sham and Sham/Sham. Mice were sensitized with aerosolized 1% ovalbumin on days 1 to 10 (sensitization phase), followed by repeated exposure on days 31 to 40 (challenge phase). Aspiration events occurred on days 1, 8,15, 22, 29, 36, 43 and 50. Animals were sacrificed on days 56 and 57.

RESULTS

Chronic aspiration of 10 microL of murine gastric fluid per week for eight weeks produced an injury pattern distinct from that of acute aspiration, with lung injury characterized by hyperplasia, neutrophil infiltration of the bronchioles and relative parenchymal sparing. Aspiration during induction of ovalbumin-induced airway hypersensitivity was associated with a trend toward decreased production of antiovalbumin IgG, antiovalbumin IgE, and total IgE. Further, aspiration induced a substantial and significant increase in antiovalbumin IgG1/IgG2a ratios, consistent with a shift toward a predominantly Th2 response.

CONCLUSION

These findings indicate that chronic aspiration has a profound effect on the nature of the immune response to aerosolized allergens in a model of experimentally induced airway hypersensitivity.

Chronic aspiration of gastric fluid induces the development of obliterative bronchiolitis in rat lung transplants

Long-term survival of a pulmonary allograft is currently hampered by obliterative bronchiolitis (OB), a form of chronic rejection that is unique to lung transplantation. While tracheobronchial aspiration from gastroesophageal reflux disease (GERD) has clinically been associated with OB, no experimental model exists to investigate this problem. Using a WKY-to-F344 rat orthotopic left lung transplant model, the effects of chronic aspiration on pulmonary allograft were evaluated. Recipients received cyclosporine with or without 8 weekly aspirations of gastric fluid into the allograft. Six (66.7%) of 9 allografts with aspiration demonstrated bronchioles with surrounding monocytic infiltrates, fibrosis and loss of normal lumen anatomy, consistent with the development of OB. In contrast, none of the allografts without aspiration (n = 10) demonstrated these findings (p = 0.002). Of the grafts examined grossly, 83% of the allografts with chronic aspiration but only 20% without aspiration appeared consolidated (p = 0.013). Aspiration was associated with increased levels of IL-1 alpha, IL-1 beta, IL-6, IL-10, TNF-alpha and TGF-beta in BAL and of IL-1 alpha, IL-4 and GM-CSF in serum. This study provides experimental evidence linking chronic aspiration to the development of OB and suggests that strategies aimed at preventing aspiration-related injuries might improve outcomes in clinical lung transplantation.

Recent progress in the development of inhibitors of human immunodeficiency virus (HIV) integrase for the management of HIV infection

Current therapy of acquired immune deficiency syndrome (AIDS) involves the use of a combination of at least three antiviral drugs to inhibit Human immunodeficiency virus 1 and 2 (HIV-1 and 2, in short HIV) replication via targeting of viral reverse transcriptase and protease. However, all anti-HIV drugs give rise to the new retroviral resistant strains. Therefore, new therapeutic agents against the emerging resistant HIV strains without secondary effects are very much needed. In HIV infection, the integration of viral DNA obtained from RNA genome into the chromosome of the host cell by viral integrase (IN) is essential for an effective viral replication. Moreover, no cellular IN has been found in the cells suggesting that viral IN appears to be one of the best candidates for the development of an antiviral drug. In recent years, promising results have proved that IN inhibitors are useful for treatment of retroviral infections. In this review, we briefly introduce IN and summarize potential inhibitors of IN, which are classified into several groups according to their origin and chemical structure. The resistance to the IN inhibitors is also discussed. Currently, several IN inhibitors are either being used in the clinical treatment or tested in clinical trials. Nevertheless, a great effort must be made to elicit wide knowledge with respect to the design of better viral inhibitors and the synthesis of new chemical derivatives with an anti-HIV activity.

Alemtuzumab in the treatment of refractory acute rejection and bronchiolitis obliterans syndrome after human lung transplantation

Despite substantial improvements in early survival after lung transplantation, refractory acute rejection (RAR) and bronchiolitis obliterans syndrome (BOS) remain major contributors to transplant-related morbidity and mortality. We have utilized alemtuzumab, a humanized anti-CD52 antibody which results in potent lymphocyte depletion, in consecutive patients with RAR (n = 12) or BOS (n = 10). All patients failed conventional treatment with methylprednisolone and antithymocyte globulin and received strict infection prophylaxis. Alemtuzumab significantly improved histological rejection scores in RAR. Total rejection grade/biopsy was 1.98 +/- 0.25 preceding alemtuzumab versus 0.33 +/- 0.14 posttreatment, p-value <0.0001 (with a similar number of biopsies/patient per respective time interval). Freedom from BOS was observed in 65% of RAR patients 2 years after alemtuzumab treatment. Although there was no statistically significant change in forced expiratory volume in 1 second (FEV1) before and after alemtuzumab treatment in patients with BOS, a stabilization or improvement in BOS grade occurred in 70% of patients. Patient survival 2 years after alemtuzumab for BOS was 69%. Despite a dramatic decline in CD4 counts in alemtuzumab-treated patients, only one patient developed a lethal infection. Thus, we provide the first evidence that alemtuzumab is a potentially useful therapy in lung transplant recipients with RAR or BOS.

Echocardiographic risk stratification for early surgery with endocarditis: a cost-effectiveness analysis

BACKGROUND

Despite widespread acceptance of echocardiography for diagnosis of infective endocarditis, few investigators have evaluated its utility as a risk-stratification tool to aid therapeutic decision-making.

METHODS

A decision tree and Markov analysis model were constructed using published and institutional data to estimate the cost-effectiveness of an echocardiographic risk-stratification strategy for infective endocarditis. The models compared surgery for high-risk patients based on clinical factors ("standard care") and surgery for high-risk patients based on echocardiographic findings ("echocardiography-guided").

RESULTS

The cost per patient for standard care and echocardiography-guided strategies was $47,766 and $53,669, respectively. The expected quality-adjusted life years (QALY) for standard care and echocardiography-guided strategies were 5.86 years and 6.10 years, respectively. Compared with standard care, the echocardiography-guided strategy cost an additional $23,867 per QALY saved. In one-way sensitivity analyses, the incremental cost of this strategy remained <$50,000/QALY across a broad range of scenarios. Baseline stroke risk had the greatest effect on cost-effectiveness. For populations with stroke risk less than 3.65%, the echocardiography-guided strategy was not cost-attractive (ICER >$50,000/QALY). At stroke risk between 3.65% and 14%, the ICER for the echocardiography-guided strategy was attractive (<$50,000 /QALY). The echocardiography-guided strategy became economically dominant at any baseline stroke risk greater than 18.3%.

CONCLUSION

Echo-guided risk stratification for early surgery in patients with large vegetations is a cost-attractive treatment strategy for IE, as it improves outcome for an incremental cost <$50,000/QALY.

Effects of hyperbaric oxygen and platelet derived growth factor on medial collateral ligament fibroblasts

PURPOSE

This study investigated hyperbaric oxygen (HBO2) and platelet-derived growth factor-BB (PDGF-BB) to determine their combined effects on fibroblasts from rabbit medial collateral ligament (MCL).

METHOD

Cells were divided into four groups: (I) Control, (II) HBO2 treatment, (III) PDGF-BB treatment and (IV) HBO2 combined with PDGF-BB treatment. All hyperoxic cells were exposed to 100% O2 at 2.5 atmospheres absolute (ATA) in a hyperbaric chamber for 120 minutes per 48 hours. Measurement of cell growth was based on increase in cell number. Cell cycle modulations were analyzed by fluorescence-activated cell sorter (FACS). Quantity of Type I and Type III collagen was determined by western blotting and image analyzer.

RESULTS

Treatment doses of HBO2 alone or PDGF-bb alone dependently increased cell growth. A combination of HBO2 treatment plus PDGF-bb treatment had an additive effect on cell growth in comparison with HBO2 treatment alone or PDGF-bb treatment alone. FACS analysis revealed that HBO2 alone, PDGF-bb alone and PDGF-bb plus HBO2 treatment increase the percentage of cells accumulated in S-phase. Western blotting analysis revealed that Type III collagen content was decreased significantly after HBO2 treatment alone or HBO2 plus PDGF-bb treatment but not in PDGF-bb treatment alone. In contrast, although Type I collagen content was increased after HBO2 treatment, the increase in Type I collagen (increase /original) was not statistically significant.

CONCLUSION

HBO2 or HBO2 plus PDGF-bb treatment decreases the Type III collagen/Type I collagen content, which could result in mechanically stronger collagen fibrils. We propose HBO2 therapy as a potentially effective treatment for MCL healing.

Continuous production of L-carnitine with NADH regeneration by a nanofiltration membrane reactor with coimmobilized L-carnitine dehydrogenase and glucose dehydrogenase

L-carnitine dehydrogenase (CDH) was partially purified from Pseudomonas putida IAM12014 for the stereospecific reduction of 3-dehydrocarnitine to L-carnitine. CDH and glucose dehydrogenase (GDH) were coimmobilized in a nanofiltration membrane bioreactor (NFMBR) for the continuous production of L-carnitine from 3-dehydrocarnitine with NADH regeneration. In the NFMBR, NAD was partially immobilized through rejection by the nanofiltration membrane and effectively regenerated by the conjugation reaction of CDH and GDH. Since 3-dehydrocarnitine was unstable at neutral pH, it was maintained under acidic conditions (pH 0.7) and supplied to the NFMBR separately from the other substrates, glucose and coenzyme NAD. As 50 mM 3-dehydrocarnitine in HCl solution, 0.05 mM NAD, and 100 mM glucose in 0.5 M Tris buffer (pH 8) were continuously supplied to the NFMBR with immobilized CDH (200 U/ml) and GDH (200 U/ml) at the retention time of 80 min and temperature of 25 degrees C, the maximum conversion, reactor productivity, and NAD regeneration number were 78%, 113 g/l/d, and 780, respectively. The half-life of the NFMBR was longer than 500 h.

Berberine inhibits arylamine N-acetyltransferase activity and gene expression in mouse leukemia L 1210 cells

N-acetyltransferases (NATs) are recognized to play a key role in the primary step of arylamine compounds metabolism. Polymorphic NAT is coded for rapid or slow acetylators, which are being thought to involve cancer risk related to environmental exposure. Berberine has been shown to induce apoptosis and affect NAT activity in human leukemia cells. The purpose of this study is to examine whether or not berberine could affect arylamine NAT activity and gene expression (NAT mRNA) and the levels of NAT protein in mouse leukemia cells (L 1210). N-acetylated and non-N-acetylated AF were determined and quantited by using high performance liquid chromatography. NAT mRNA was determined and quantited by using RT-PCR. The levels of NAT protein were examined by western blotting and determined by using flow cytometry. Berberine displayed a dose-dependent inhibition to cytosolic NAT activity and intact mice leukemia cells. Time-course experiments indicated that N-acetylation of AF measured from intact mice leukemia cells were inhibited by berberine for up to 24 h. The NAT1 mRNA and NAT proteins in mouse leukemia cells were also inhibited by berberine. This report is the first demonstration, which showed berberine affect mice leukemia cells NAT activity, gene expression (NAT1 mRNA) and levels of NAT protein.

Demonstration of different modes of cell death upon herpes simplex virus 1 infection in different types of oral cells

The effects of Herpes simplex virus 1 (HSV-1) infection on five different types of oral cancerous cells (neck metastasis of gingival carcinoma (GNM) cells and tongue squamous cells of carcinoma (TSCCa) and non-cancerous cells (buccal mucosal fibroblasts (BF), gingival fibroblasts (GF), oral submucosal fibrosis cells (OSF)) and one type of non-oral cancerous cells (KB cells) were investigated. In HSV-1-infected cells the cell viability, CPE, viral antigens accumulation, caspase-3 activity, annexin V binding and DNA fragmentation were estimated. Three different forms or pathways of cell death were considered: apoptosis (the presence or rise of caspase-3 activity, DNA fragmentation and annexin V binding), slow cell death (the presence or rise of DNA fragmentation, the absence or decline of caspase-3 activity and annexin V binding), and necrosis (the absence of decline of caspase-3 activity, DNA fragmentation and annexin V binding). The viability of all cell types, except for KB cells, was reduced by the infection. CPE and viral antigens data demonstrated that all six types of cells could be infected with HSV-1. Upon HSV-1 infection there occurred (i) a classical apoptosis in GF cells, (ii) apoptosis in the early phase of infection and necrosis in the late phase of infection in GNM and TSCCa cells, (iii) slow cell death followed by necrosis in BF and OSF cells (however, these cells showed a different type of CPE), (iv) a classical slow cell death in KB cells. It is hypothesized that HSV-1 infection has a potential to induce several distinct pathways leading to cell death or several forms of cell death. Moreover, more than one pathway may be involved in the death of particular cell type. As HSV-1 was demonstrated to infect different oral and non-oral cells and cause different pathways or forms of cell death, the safety of using HSV-1 as a vector for gene therapy should be re-considered.

Inhibition of N-acetyltransferase activity and gene expression in human colon cancer cell lines by diallyl sulfide

Diallyl sulfide (DAS) is one of the major components of garlic (Allium sativum) and is widely used in the world for food. In this study, DAS was selected for testing the inhibition of arylamine N-acetyltransferase (NAT) activity (N-acetylation of 2-aminofluorene) and gene expression (mRNA NAT) in human colon cancer cell lines (colo 205, colo 320 DM and colo 320 HSR). The NAT activity was examined by high performance liquid chromatography and indicated that a 24 h DAS treatment decreases N-acetylation of 2-aminofluorene in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The NAT enzymes (protein) were analyzed by western blotting and flow cytometry and it indicated that DAS decreased the levels of NAT in three colon (colo 205, 320 DM and colo 320 HSR) cancer cell lines. The gene expression of NAT (mRNAT NAT) was determined by polymerase chain reaction (PCR), it was shown that DAS affect mRNA NAT expression in examined human colon cancer cell lines. This report is the first to demonstrate that DAS does inhibit human colon cancer cell NAT activity and gene expression.

Factors associated with missing birthplace information in a population-based cancer registry

Differences in cancer occurrence within a racial/ethnic group may be influenced by migrant status or level of acculturation, which can indicate variations in environmental exposures. When immigration and acculturation data on individual patients are not available, birthplace may serve as a proxy. As part of a larger study intended to assess the utility of the birthplace variable in the Greater Bay Area Cancer Registry (GBACR), part of the Surveillance, Epidemiology, and End Results (SEER) program, we measured its completeness, and determined whether missing birthplace is associated with patient and hospital reporting source characteristics. Subjects were persons diagnosed with cancer within the GBACR surveillance area during the period 1988-1996. Of the 204,553 subjects, 67% had birthplace recorded in the registry. Deceased persons were 10 times more likely than living persons to have data on birthplace. Racial/ethnic groups which included more foreign-born persons, such as Southeast Asians, tended to have more complete birthplace information than did groups with fewer foreign-born, such as Japanese and Hispanics. The effects of patient and reporting source characteristics on birthplace completeness differed across racial/ethnic groups. These data indicate that completeness of the birthplace variable in the GBACR is biased, and that investigators considering birthplace in analyses of SEER data should consider these biases. For birthplace data to be useful, completeness needs to be improved at the level of the diagnosing facility.

Ellagic [correction of ellagica] acid inhibits arylamine N-acetyltransferase activity and DNA adduct formation in human bladder tumor cell lines (T24 and TSGH 8301)

The fact that vitamin C (ascorbic acid) exhibits a protective effect in certain types of cancer is well documented. Our previous studies demonstrated that human bladder tumor cell line (T24) has N-acetyltransferase (NAT) activity in cytosols and intact cells. The present studies examined the inhibition of arylamine NAT activity and carcinogen (2-aminofluorene)-DNA adduct formation by ellagic acid (EA) in human bladder tumor cell lines (T24 and TSGH 8301). Two assay systems were performed, one with cellular cytosols (9,000 g supernatant), the other with intact bladder tumor cell suspensions. NAT activity and 2-aminofluorene-DNA adduct formation in T24 and TSGH 8301 cells was inhibited by EA in a dose-dependent manner in both systems, i.e.. the greater the concentration of EA in the reaction the greater the inhibition of NAT activity (dose- and time-course dependent effects). The data also indicated that EA decreased the apparent Km and Vmax of NAT enzymes from T24 and TSGH 8301 cells in cytosols. NAT activity and 2-aminofluorene-DNA adducts in T24 is higher than in TSGH 8301. This report is the first to demonstrate that EA affects human bladder tumor cell NAT activity.

Integrase mediates nuclear localization of Ty3

Retroviruses in nondividing cells and yeast retrotransposons must transit the nuclear membrane in order for integration to occur. Mutations in a bipartite basic motif in the carboxyl-terminal domain of the Ty3 integrase (IN) protein were previously shown to block transposition at a step subsequent to 3'-end processing of Ty3 extrachromosomal DNA. In this work, the Ty3 IN was shown to be sufficient to target green fluorescent protein to the nucleolus. Mutations in the bipartite basic motif abrogated this localization. The region containing the motif was shown to be sufficient for nuclear but not subnuclear localization of a heterologous protein. Viruslike particles (VLPs) from cells expressing a Ty3 element defective for nuclear localization were inactive in an in vitro integration assay, suggesting that nuclear entry is required to form active VLPs or that this motif is required for post-nuclear entry steps. Ty3 inserts at transcription initiation sites of genomic tRNA genes and plasmid-borne 5S and U6 RNA genes transcribed by RNA polymerase III. In situ hybridization with Ty3- and Ty3 long terminal repeat-specific probes showed that these elements which are associated with tRNA genes do not colocalize with the ribosomal DNA (rDNA). However, a PCR assay of cells undergoing transposition showed that Ty3 insertion does occur into the 5S genes, which, in yeast, are interspersed with the rDNA and therefore, like Ty3 IN, associated with the nucleolus.

Over-expression of FoxM1 stimulates cyclin B1 expression

FoxM1 (previously named WIN, HFH-11 or Trident) is a Forkhead box (Fox) transcription factor widely expressed in proliferating cells. Various findings, including a recent analysis of FoxM1 knockout mice, suggest that FoxM1 is required for normal S-M coupling during cell cycle progression. To study the regulatory role of FoxM1 and its downstream regulatory targets, three stably transfected HeLa lines that display doxycycline (dox)-inducible FoxM1 expression were established. Over-expression of FoxM1 by dox induction facilitates growth recovery from serum starvation. Quantitation of cyclin B1 and D1 levels using flow cytometric, Western and Northern analyses reveals that elevated FoxM1 levels lead to stimulation of cyclin B1 but not cyclin D1 expression. Transient reporter assays in the dox-inducible lines and upon co-transfection with a constitutive FoxM1 expression plasmid suggest that FoxM1 can activate the cyclin B1 promoter.

Enhanced activity and stability of a Cu/SiO2 catalyst for the reverse water gas shift reaction by an iron promoter

An Fe promoter inhibits the sintering of Cu particles and oxidation of the Cu surface, resulting in high catalyst activity and stability.

Enhanced gluconeogenesis and increased energy storage as hallmarks of aging in Saccharomyces cerevisiae

A relationship between life span and cellular glucose metabolism has been inferred from genetic manipulations and caloric restriction of model organisms. In this report, we have used the Snf1p glucose-sensing pathway of Saccharomyces cerevisiae to explore the genetic and biochemical linkages between glucose metabolism and aging. Snf1p is a serine/threonine kinase that regulates cellular responses to glucose deprivation. Loss of Snf4p, an activator of Snf1p, extends generational life span whereas loss of Sip2p, a presumed repressor of the kinase, causes an accelerated aging phenotype. An annotated data base of global age-associated changes in gene expression in isogenic wild-type, sip2Delta, and snf4Delta strains was generated from DNA microarray studies. The transcriptional responses suggested that gluconeogenesis and glucose storage increase as wild-type cells age, that this metabolic evolution is exaggerated in rapidly aging sip2Delta cells, and that it is attenuated in longer-lived snf4Delta cells. To test this hypothesis directly, we applied microanalytic biochemical methods to generation-matched cells from each strain and measured the activities of enzymes and concentrations of metabolites in the gluconeogenic, glycolytic, and glyoxylate pathways, as well as glycogen, ATP, and NAD(+). The sensitivity of the assays allowed comprehensive biochemical profiling to be performed using aliquots of the same cell populations employed for the transcriptional profiling. The results provided additional evidence that aging in S. cerevisiae is associated with a shift away from glycolysis and toward gluconeogenesis and energy storage. They also disclosed that this shift is forestalled by two manipulations that extend life span, caloric restriction and genetic attenuation of the normal age-associated increase in Snf1p activity. Together, these findings indicate that Snf1p activation is not only a marker of aging but also a candidate mediator, because a shift toward energy storage over expenditure could impact myriad aspects of cellular maintenance and repair.

Crystallization and preliminary X-ray diffraction analysis of the 1,3-1,4-beta-D-glucanase from Fibrobacter succinogenes

The truncated 1,3-1,4-beta-glucanase (1,3-1,4-beta-D-glucan 4-glucanohydrolase; E.C. 3.2.1.73) from Fibrobacter succinogenes was crystallized in four different forms by the vapour-diffusion method. Form A crystals have the largest trigonal P321 unit cell, diffracting to 3.0 A resolution with four to six molecules per asymmetric unit. Form B and C crystals belong to the same monoclinic space group P2(1), but the form B unit cell is twice as large as the unit cell of form C. Form B crystals diffract to 2.5 A resolution and contain four molecules per asymmetric unit. Form C crystals diffract to 2.1 A resolution and contain two molecules per asymmetric unit. Form D crystals have the smallest orthorhombic P2(1)2(1)2(1) unit cell, containing only one molecule per asymmetric unit, and diffract beyond 2.1 A resolution. The crystallization conditions for form B and C crystals are almost identical, except that form C crystals were grown in the presence of 2 mM Ca(2+) ions. It is likely that Ca(2+) directly binds to the glucanase, leading to unit-cell shrinkage as observed in other Bacillus glucanase crystals. A self-rotation search identified non-crystallographic twofold axes that combine with the crystallographic twofold dyads to give 222 symmetry for both form A and form B crystals, indicating that the glucanase has a tendency to pack in 222 symmetry.

Serological and Molecular Characterization of Peanut chlorotic fan-spot virus, a New Species of the Genus Tospovirus

ABSTRACT To clarify the serological relationship of Peanut chlorotic fan-spot virus (PCFV) with other tospoviruses, antisera were produced against the nucleocapsid (N) proteins of this virus and tospoviruses from four serogroups including Tomato spotted wilt virus (TSWV), Impatiens necrotic spot virus (INSV), Groundnut ringspot virus (GRSV), and Watermelon silver mottle virus (WSMoV). In immunodiffusion tests, the antisera only reacted with their homologous antigens. Similar results were noticed in indirect enzyme-linked immunosorbent assay and immunoblot tests, with the exception that strong cross-reactions were observed in heterologous combinations between TSWV and GRSV. The results indicated that the N protein of PCFV is not serologically related to those of the tospoviruses from the four serogroups. To further characterize the virus, viral S double-stranded RNA was extracted from PCFV-infected Chenopodium quinoa and used for cDNA cloning and sequencing. The full-length viral strand of the S RNA was determined to be 2,833 nucleotides, with an inverted repeat at the 5' and 3' ends and two open reading frames in an ambisense arrangement. The 3'-terminal sequence (5'-AUUGCUCU-3') of the viral S RNA is identical to those of other tospoviruses, indicating that PCFV belongs to the genus Tospovirus. The N and the NSs proteins of PCFV share low amino acid identities (22.3 to 67.5% and 19.3 to 54.2%) with those of reported tospoviruses, respectively. The phylogenetic dendrogram of the N gene of PCFV compared with those of other tospoviruses indicates that PCFV is distinct from other tospoviruses. In hybridization analyses, an N gene cDNA probe of PCFV did not react with viral RNAs of TSWV, GRSV, INSV, and WSMoV, and vice versa. Thus, based on these results, we conclude that PCFV is a new tospovirus species.

Therapeutic strategies for xenograft rejection

The increasing demand for transplantable organs over the past several decades has stimulated the idea of using animal organs in lieu of cadaveric organs in clinical transplantation. Pigs are now considered to be the most suitable source of organs for transplantation because of their abundant availability, their appropriate size, their relatively short gestation period, and the recent development in the technology to genetically manipulate them. In the past few years, some of the seemingly complex immunologic responses in pig-to-primate transplantation have been elucidated. This progress has allowed us to focus our efforts on devising specific therapeutic strategies to overcome or prevent some of the responses that contribute to rejection of the xenograft. In this article, we review the various approaches that might allow clinical xenotransplantation to come to fruition.

Inhibitory actions of luteolin on the growth and arylamine N-acetyltransferase activity in strains of Helicobacter pylori from ulcer patients

Helicobacter pylori is now recognized as an important cause of type B gastritis, which is strongly associated with gastric and duodenal ulcer disease. H. pylori may be a causative factor in patients with gastric cancer. The growth inhibition and N-acetylation of 2-Aminofluorene (AF) or P-aminobenzoic acid (PABA) by arylamine N-acetyltransferase (NAT) in H. pylori were inhibited by luteolin, a component in herbal medicine. The growth inhibition was based on the changes of optical density (OD) by using a spectrophotometer. The N-acetylation of AF or PABA by NAT from H. pylori were assayed by the amounts of acetylated and non-acetylated AF or PABA in cytosols and intact bacteria of H. pylori by using HPLC. An inhibition of growth on H. pylori demonstrated that luteolin elicited a dose-dependent growth inhibition in the H. pylori cultures. Cytosols and suspensions of H. pylori with or without specific concentrations of luteolin co-treatment showed different percentages of AF or PABA acetylation. The data indicated that there was decreased NAT activity associated with increased levels of luteolin in H. pylori cytosols and suspensions. Using standard steady-state kinetic analysis, it was demonstrated that luteolin was a possible uncompetitive inhibitor to NAT enzyme in H. pylori. This report is the first demonstration to show that luteolin can inhibit H. pylori growth and NAT activity.

Analysis of attitudes toward computer networks and Internet addiction of Taiwanese adolescents

This study explored the interplay between young people's attitudes toward computer networks and Internet addiction. Ninety possible Internet addicts were selected for examination after analyzing the questionnaire responses of an initial sample of 753 Taiwanese high school adolescents. It was found that the subjects' attitudes toward computer networks could explain many aspects of Internet addiction. However, actual behaviors on Internet usage and perceptions on the usefulness of Internet were more important than affective responses toward computer networks in predicting adolescents' Internet addiction.

Prediction of coronary artery disease in patients undergoing operations for mitral valve degeneration

OBJECTIVES

We sought to develop and validate a model that estimates the risk of obstructive coronary artery disease in patients undergoing operations for mitral valve degeneration and to demonstrate its potential clinical utility.

METHODS

A total of 722 patients (67% men; age, 61 +/- 12 years) without a history of myocardial infarction, ischemic electrocardiographic changes, or angina who underwent routine coronary angiography before mitral valve prolapse operations between 1989 and 1996 were analyzed. A bootstrap-validated logistic regression model on the basis of clinical risk factors was developed to identify low-risk (< or =5%) patients. Obstructive coronary atherosclerosis was defined as 50% or more luminal narrowing in one or more major epicardial vessels, as determined by means of coronary angiography.

RESULTS

One hundred thirty-nine (19%) patients had obstructive coronary atherosclerosis. Independent predictors of coronary artery disease include age, male sex, hypertension, diabetes mellitus,and hyperlipidemia. Two hundred twenty patients were designated as low risk according to the logistic model. Of these patients, only 3 (1.3%) had single-vessel disease, and none had multivessel disease. The model showed good discrimination, with an area under the receiver-operating characteristic curve of 0.84. Cost analysis indicated that application of this model could safely eliminate 30% of coronary angiograms, corresponding to cost savings of $430,000 per 1000 patients without missing any case of high-risk coronary artery disease.

CONCLUSION

A model with standard clinical predictors can reliably estimate the prevalence of obstructive coronary atherosclerosis in patients undergoing mitral valve prolapse operations. This model can identify low-risk patients in whom routine preoperative angiography may be safely avoided.

Missed and associated injuries after subtalar dislocation: the role of CT

Subtalar joint dislocation (STJD) is an uncommon injury, but carries with it a potential for significant functional disability. We hypothesized that a significant number of injuries associated with subtalar joint dislocation may be unrecognized by plain radiographic examination. Therefore, we reviewed the records of all STJDs over a three-year period, identifying nine cases. The majority of injuries occurred in men (78%) with a mean age of 29 years. Overall, the mean age at injury was 32 years. The right lower extremity was most frequently injured (87.5%). Plain films initially diagnosed a STJ dislocation in all patients. A CT scan was performed in all cases. In 100% of patients, CT identified additional injuries missed on initial plain radiographs. In 44% of patient, new information gathered by CT dictated a change in treatment. Based on our findings, we conclude that CT is an invaluable tool to assess for associated injuries in STJ dislocation, and should be performed in all cases of STJ dislocation.

Effects of the butylated hydroxyanisole and butylated hydroxytoluene on the DNA adduct formation and arylamines N-acetyltransferase activity in human colon tumor cells

The effects of butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) on N-acetyltransferase (NAT) activity were examined using a human colon tumor cell line (colo 205). BHA or BHT were added to the cytosols or to the medium of human colon tumor cells: The NAT activity was measured by high performance liquid chromatography, assaying the amounts of acetylated 2-aminoflluorene (AAF), p aminobenzoic acid (N-Ac-PABA), nonacetylated 2 aminofluorene (AF) and p-aminobenzoic acid (PABA). The NAT activity in the human colon tumor cells and cytosols was suppressed by BHA or BHT in a dose-dependent manner. The apparent values of Km and Vmax of NAT of human colon tumor cells were also decreased by BHA or BHT in cytosols and in intact cells. BHA or BHT may act as a noncompetitive inhibitor. After the incubation of human colon tumor cells with AF in the presence of BHA or BHT, the cells were recovered and DNA was prepared and hydrolysed to nucleotides. Adducted nucleotides were extracted into butanol and AF-DNA adducts were analysed by HPLC. The results also demonstrated that when BHA or BHT was added to the media, a decrease in AF-DNA adduct formation was seen in the human colon tumor cells. The finding of AF-DNA adduct formation in cultured human colon tumor cells suggest the possibility of using cultured cells for assessing arylamine-induced DNA damage.

Dietary fat and breast cancer

One of the most often studied associations in epidemiology is dietary fat and breast cancer risk. That migrants from low-risk countries increase their risk on immigrating to higher-risk countries suggests that some modifiable lifestyle or environmental factor is responsible for the development of breast cancer. Although early international correlational studies and experimental animals studies support dietary fat as a risk factor for breast cancer, more recent data from case-control studies and cohort studies have been equivocal, thus the analytical data do not support a strong positive association. The conflicting results from analytic studies may be due to methodologic issues associated with study design, dietary assessment tools, measurement error, improper statistical analyses, and a lack of heterogeneity in fat intake among the study population. Moreover, current dietary questionnaires may be inadequate in capturing true dietary intakes or capturing the risk with exposure during earlier periods of a woman's life. Although two large clinical trials investigating the fat/breast cancer relationships issue are underway, researchers are generally skeptical at their ability to detect an independent association between fat and breast cancer risk. Further epidemiologic studies using current methodology may not prove to be fruitful in generating definitive answers to shed light on this controversial issue. In addition, rather than concentrating on dietary fat, researchers should focus on diets that are not only low in saturated fat, but also high in fruit and vegetable consumption. Researchers should take advantage of advances in molecular and genetic technology for a different perspective in examining the issue. For example, markers of susceptibility to breast cancer that can detect women at higher risk for breast cancer may be helpful in clarifying the role of dietary fat. More comprehensive and multiple approaches to studying dietary factors and breast cancer are recommended.

Biophysical characteristics of anti-Gal(alpha)1-3Gal IgM binding to cell surfaces: implications for xenotransplantation

BACKGROUND

Natural antibodies directed against cell surface carbohydrates are thought to be vital to host defense and to initiate the rejection of xenografts and ABO-incompatible allografts. The biophysical properties underlying the association and dissociation of these antibodies from cell surfaces is incompletely understood. We investigated those properties for the binding of Galalpha1-3Gal antibodies to porcine endothelial cell surfaces, because such interactions might be relevant to the clinical application of xenotransplantation.

RESULTS AND CONCLUSIONS

The initial rate of binding of anti-Galalpha1-3Gal antibodies to endothelial cells was found to depend on antibody concentration, antibody diffusion, and antigen concentration. The presence of an intact glycocalyx had a greater impact on antibody binding than mobility of antigen in cell membranes. Disruption of glycocalyx increased the amount of antibody bound at equilibrium by more than 50%. Although the binding of anti-Galalpha1-3Gal antibodies to cell surfaces could be inhibited by soluble Galalpha1-3Gal, once bound, some anti-Galalpha1-3Gal could not be dissociated by competitive inhibitors of binding or by denaturation of the bound Ig with chaotropic reagents, but could be dissociated by reduction of disulfide bonds, suggesting that attachment to cell surfaces was, at least in part, by means other than specific reaction with the epitope.