Streptococcus suis meningoencephalitis diagnosed with metagenomic next-generation sequencing: A case report with literature review

Streptococcus suis is a pathogen of emerging zoonotic diseases and meningoencephalitis is the most frequent clinical symptom of S. suis infection in humans. Rapid diagnosis of S. suis meningoencephalitis is critical for the treatment of the disease. While the current routine microbiological tests including bacterial culture and gram staining are poorly sensitive, diagnosis of S. suis meningoencephalitis by metagenomic next-generation sequencing (mNGS) has been rarely reported. Here, we report a 52-year-old female pork food producer with a broken finger developed S. suis meningoencephalitis. After her admission, no pathogenic bacteria were detected through bacterial culture and Gram staining microscopy in the cerebrospinal fluid obtained via lumbar puncture. However, mNGS identified the presence of S. suis in the sample. mNGS is a promising diagnostic tool for rapid diagnosis of rare infectious diseases in the central nervous system.

Microbiota in adult perianal abscess revealed by metagenomic next-generation sequencing

The microbiota of perianal abscesses is scarcely investigated. Identifying causative bacteria is essential to develop antibiotic therapy. However, culture-based methods and molecular diagnostics through 16S PCR technology are often hampered by the polymicrobial nature of perianal abscesses. We sought to characterize the microbiota composition of perianal abscesses via metagenomic next-generation sequencing (mNGS). Fourteen patients suffering from perianal abscesses between March 2023 and August 2023 underwent retrospective assessment. Information from medical records was used, including clinical information, laboratory data, and culture and mNGS results. Forty bacterial taxa were identified from perianal abscesses through mNGS, with Bilophila wadsworthia (71.4%), Bacteroides fragilis (57.1%), and Escherichia coli (50.0%) representing the most prevalent species. mNGS identified an increased number of bacterial taxa, with an average of 6.1 compared to a traditional culture-based method which only detected an average of 1.1 in culture-positive perianal abscess patients, predominantly E. coli (75.0%), revealing the polymicrobial nature of perianal abscesses. Our study demonstrates that a more diverse bacterial profile is detected by mNGS in perianal abscesses, and that Bilophila wadsworthia is the most prevalent microorganism, potentially serving as a potential biomarker for perianal abscess.IMPORTANCEAccurately, identifying the bacteria causing perianal abscesses is crucial for effective antibiotic therapy. However, traditional culture-based methods and 16S PCR technology often struggle with the polymicrobial nature of these abscesses. This study employed metagenomic next-generation sequencing (mNGS) to comprehensively analyze the microbiota composition. Results revealed 40 bacterial taxa, with Bilophila wadsworthia (71.4%), Bacteroides fragilis (57.1%), and Escherichia coli (50.0%) being the most prevalent species. Compared to the culture-based approach, mNGS detected a significantly higher number of bacterial taxa (average 6.1 vs 1.1), highlighting the complex nature of perianal abscesses. Notably, Bilophila wadsworthia emerged as a potential biomarker for these abscesses. This research emphasizes the importance of mNGS in understanding perianal abscesses and suggests its potential for improving diagnostic accuracy and guiding targeted antibiotic therapy in the future.

Measurements of All-Particle Energy Spectrum and Mean Logarithmic Mass of Cosmic Rays from 0.3 to 30 PeV with LHAASO-KM2A

We present the measurements of all-particle energy spectrum and mean logarithmic mass of cosmic rays in the energy range of 0.3-30 PeV using data collected from LHAASO-KM2A between September 2021 and December 2022, which is based on a nearly composition-independent energy reconstruction method, achieving unprecedented accuracy. Our analysis reveals the position of the knee at 3.67±0.05±0.15  PeV. Below the knee, the spectral index is found to be -2.7413±0.0004±0.0050, while above the knee, it is -3.128±0.005±0.027, with the sharpness of the transition measured with a statistical error of 2%. The mean logarithmic mass of cosmic rays is almost heavier than helium in the whole measured energy range. It decreases from 1.7 at 0.3 PeV to 1.3 at 3 PeV, representing a 24% decline following a power law with an index of -0.1200±0.0003±0.0341. This is equivalent to an increase in abundance of light components. Above the knee, the mean logarithmic mass exhibits a power law trend towards heavier components, which is reversal to the behavior observed in the all-particle energy spectrum. Additionally, the knee position and the change in power-law index are approximately the same. These findings suggest that the knee observed in the all-particle spectrum corresponds to the knee of the light component, rather than the medium-heavy components.

Performance of metagenomic next-generation sequencing in cerebrospinal fluid for diagnosis of tuberculous meningitis

Purpose. Metagenomic next-generation sequencing (mNGS) has been widely used in the diagnosis of infectious diseases, while its performance in diagnosis of tuberculous meningitis (TBM) is incompletely characterized. The aim of this study was to assess the performance of mNGS in the diagnosis of TBM, and illustrate the sensitivity and specificity of different methods.Methods. We retrospectively recruited TBM patients between January 2021 and March 2023 to evaluate the performance of mNGS on cerebrospinal fluid (CSF) samples, in comparison with conventional microbiological testing, including culturing of Mycobacterium tuberculosis (MTB), acid-fast bacillus (AFB) stain, reverse transcription PCR and Xpert MTB/RIF.Results. Of the 40 enrolled, 34 participants were diagnosed with TBM, including 15(44.12 %) definite and 19(55.88 %) clinical diagnosis based upon clinical manifestations, CSF parameters, brain imaging, pathogen evidence and treatment response. The mNGS method identified sequences of Mycobacterium tuberculosis complex (MTBC) in 11 CSF samples. In patients with definite TBM, the sensitivity, specificity, positive predictive value, negative predictive value and accuracy of mNGS were 78.57, 100, 100, 66.67 and 85 %, respectively. Compared to conventional diagnostic methods, the sensitivity of mNGS (78.57 %) was higher than AFB (0 %), culturing (0 %), RT-PCR (60 %) and Xpert MTB/RIF (14.29 %).Conclusions. Our study indicates that mNGS of CSF exhibited an overall improved sensitivity over conventional diagnostic methods for TBM and can be considered a front-line CSF test.

Systemic and cerebrospinal fluid biomarkers for tuberculous meningitis identification and treatment monitoring

IMPORTANCE

Tuberculous meningitis is a life-threatening infection with high mortality and disability rates. Current diagnostic methods using cerebrospinal fluid (CSF) samples have limited sensitivity and lack predictive biomarkers for evaluating prognosis. This study's findings reveal excessive activation of the immune response during tuberculous meningitis (TBM) infection. Notably, a strong negative correlation was observed between CSF levels of monokine induced by interferon-γ (MIG) and the CSF/blood glucose ratio in TBM patients. MIG also exhibited the highest area under the curve with high sensitivity and specificity. This study suggests that MIG may serve as a novel biomarker for differentiating TBM infection in CSF or serum, potentially leading to improved diagnostic accuracy and better patient outcomes.

[Epidemiological characteristics of public health emergency events of varicella in China, 2006-2021]

Objective: To understand the epidemiological characteristics of public health emergency events (PHEE) of varicella in China from 2006 to 2021 and related response performances. Methods: The data of varicella PHEE in 31 provinces of China from 2006 to 2021 were collected through the Public Health Emergency Management Information System, Microsoft Excel 2019 software and SPSS 26.0 statistical software were used to conduct descriptive epidemiological, statistical analysis on the time, area, location distribution, scale and epidemic management. Results: A total of 11 443 PHEE involving 341 048 related cases were reported from 2006 to 2021, with an annual attack rate of 1.78%-3.80% and a total attack rate of 2.33% (341 048/14 624 042). The number of PHEE and related cases of varicella decreased from 1 107 (35 349) in 2007 to 262 (6 884) in 2012 (Z=-2.40, P<0.001), then increased year by year to 1 318 (42 649) in 2019 (Z=2.58, P<0.001), with a significant decline since 2020. The varicella PHEE in China presents the seasonal characteristics,the peak is from April to June and from October to December, respectively. The sub-peak of varicella PHEE in eastern China generally appears 1-2 months earlier than in central and western China. Varicella PHEE reports are mainly distributed in eastern China, the attack rate is relatively high in western China, school-reported varicella PHEE was 88.26% of the total reports (10 099/11 443). The epidemic scale of varrcella PHEE typically range from 10 to 29 cases per year among the given outbreaks. The M (Q1, Q3) of average number of cases, average duration, and average reporting interval of PHEE were 23 (16,35), 20 (14, 26) days, and 9 (5,19) days, respectively, and the reporting interval was positively correlated with the duration (r=0.854, P<0.001). Conclusions: The varicella PHEE in China from 2006 to 2021 has not been effectively controlled. Schools are the key places to prevent and control varicella PHEE. Improving the sensitivity of varicella PHEE monitoring, strengthening the timely disposal of varicella epidemic, and promoting varicella vaccination are effective measures to prevent and control varicella PHEE.

Measurement of Ultra-High-Energy Diffuse Gamma-Ray Emission of the Galactic Plane from 10 TeV to 1 PeV with LHAASO-KM2A

The diffuse Galactic γ-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays in the Milky Way. In this Letter, we report the measurements of diffuse γ rays from the Galactic plane between 10 TeV and 1 PeV energies, with the square kilometer array of the Large High Altitude Air Shower Observatory (LHAASO). Diffuse emissions from the inner (15°10  TeV). The energy spectrum in the inner Galaxy regions can be described by a power-law function with an index of -2.99±0.04, which is different from the curved spectrum as expected from hadronic interactions between locally measured cosmic rays and the line-of-sight integrated gas content. Furthermore, the measured flux is higher by a factor of ∼3 than the prediction. A similar spectrum with an index of -2.99±0.07 is found in the outer Galaxy region, and the absolute flux for 10≲E≲60  TeV is again higher than the prediction for hadronic cosmic ray interactions. The latitude distributions of the diffuse emission are consistent with the gas distribution, while the longitude distributions show clear deviation from the gas distribution. The LHAASO measurements imply that either additional emission sources exist or cosmic ray intensities have spatial variations.

A tera-electron volt afterglow from a narrow jet in an extremely bright gamma-ray burst

Some gamma-ray bursts (GRBs) have a tera-electron volt (TeV) afterglow, but the early onset of this has not been observed. We report observations with the Large High Altitude Air Shower Observatory of the bright GRB 221009A, which serendipitously occurred within the instrument field of view. More than 64,000 photons >0.2 TeV were detected within the first 3000 seconds. The TeV flux began several minutes after the GRB trigger, then rose to a peak about 10 seconds later. This was followed by a decay phase, which became more rapid ~650 seconds after the peak. We interpret the emission using a model of a relativistic jet with half-opening angle ~0.8°. This is consistent with the core of a structured jet and could explain the high isotropic energy of this GRB.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

[Pathological features related to onco-immunity and their clinical significance of pancreatic ductal adenocarcinoma]

Objective: To investigate the tumor immunity-related pathologic features and clinical significance in pancreatic ductal adenocarcinoma (PDAC). Methods: All pathologic materials and clinical information of 192 PDAC patients from the Cancer Hospital of the University of Chinese Academy of Sciences from January 2010 to December 2020 were collected. The onco-immune microenvironment associated morphologic features were evaluated, and MHC-Ⅰ, PD-L1, CD3, and CD8 expression were detected by immunohistochemistry (IHC). Then the correlation between the factors and their influence on prognosis was analyzed. Results: There were 163 cases of non-specific adenocarcinoma (163/192, 84.90%), 18 cases of adeno-squamous carcinoma (18/192, 9.37%), and 11 cases of other rare subtypes (11/192, 5.73%). Perineural invasion was observed in 110 cases (110/192, 57.29%) and vascular invasion in 86 cases (86/192, 44.79%). There were 84 cases (84/182, 46.15%) with severe chronic inflammation. Tumor infiltrating immune cell numbers (TII-N) were increased in 52 cases (52/192, 27.08%). Lymphocytes and plasma cells were the main infiltrating immune cells in 60 cases (60/192, 31.25%), whereas in 34 cases (34/192, 17.71%) the tumors were mainly infiltrated by granulocytes, and 98 cases (98/192, 51.04%) showed mixed infiltration. CD3+T cells were deficient in 124 cases (124/192, 66.31%). CD8+T cells were deficient in 152 cases (152/192, 79.58%). MHC-Ⅰ expression was down-regulated in 156 cases (156/192, 81.25%), and PD-L1 was positive (CPS≥1) in 46 cases (46/192, 23.96%). Statistical analysis showed that TII-N was negatively correlated with vascular invasion (P=0.035), perineural invasion (P=0.002), stage (P=0.004) and long-term alcohol consumption (P=0.039). The type of immune cells correlated positively with chronic pancreatic inflammation (P=0.002), and negatively with tumor differentiation (P=0.024). CD8+T cells were positively correlated with CD3+T cells (P=0.032), MHC-Ⅰ expression (P<0.001) and PD-L1 expression (P=0.001), and negatively correlated with long-term smoking (P=0.016). Univariate analysis showed that histological nonspecific type (P=0.013) and TII-N (P<0.001) were the factors for good prognosis. Vascular invasion (P=0.032), perineural invasion (P=0.001), high stage (P=0.003) and long-term alcohol consumption (P=0.004) were adverse prognostic factors. COX multivariate risk analysis found that TII-N was an independent favorable factor for PDAC, while perineural invasion was an independent adverse risk factor. Conclusions: TII-N is an independent superior prognostic factor for PDAC, and significantly correlated with many factors; chronic alcohol consumption and smoking may inhibit onco-immunity in PDAC patients.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[A clinical analysis of 10 cases with cardiac lymphoma]

目的

分析心脏淋巴瘤的发病情况、临床特征、治疗效果及预后。

方法

收集2000年1月至2016年6月期间确诊并有心脏累及的10例淋巴瘤患者的资料，对患者的一般资料、临床表现、病理诊断、实验室检查、心脏累及方式、心脏并发症、治疗方式、疗效及预后进行分析。

结果

3 918例淋巴瘤患者中，心脏累及者10例，其中原发性心脏淋巴瘤（PCL）1例（主要累及左右心房，以心肌内多发结节包块为主），继发性心脏淋巴瘤（SCL）9例（主要为心包包块，其中出现心包积液5例，心肌肿块2例）。男性6例，女性4例，中位年龄55（19~88）岁，主要临床表现为呼吸困难7例，胸痛5例，乏力、水肿各2例。病理类型包括弥漫大B细胞淋巴瘤（DLBCL）7例，T淋巴母细胞淋巴瘤、霍奇金淋巴瘤、Burkitt淋巴瘤各1例。心脏并发症包括充血性心力衰竭7例，心律失常4例（主要为窦性心动过速、心房颤动和房室传导阻滞）。除1例高龄、一般状况差未接受治疗外，其余9例患者均接受治疗（单纯化疗4例，化疗联合放疗5例）。中位随访时间为9（1~28）个月。1例PCL患者化疗后获部分缓解（PR），无进展生存（PFS）期为6个月，总生存（OS）期为21个月。SCL患者中6例起病累及心脏者，治疗后1例获完全缓解，5例获PR，中位PFS期为5个月，中位OS期为19个月；3例病情进展累及心脏者，2例治疗后获PR，1例未治疗者死亡，中位PFS期为4个月，OS因数据截尾，未能获得。

结论

心脏淋巴瘤为少见类型，DLBCL为最常见类型，呼吸困难、胸痛为最常见临床表现，并易出现充血性心力衰竭和心律失常，治疗以系统化疗为主，总体预后差。

Dynamic nucleotide mutation gradients and control region usage in squamate reptile mitochondrial genomes

Gradients of nucleotide bias and substitution rates occur in vertebrate mitochondrial genomes due to the asymmetric nature of the replication process. The evolution of these gradients has previously been studied in detail in primates, but not in other vertebrate groups. From the primate study, the strengths of these gradients are known to evolve in ways that can substantially alter the substitution process, but it is unclear how rapidly they evolve over evolutionary time or how different they may be in different lineages or groups of vertebrates. Given the importance of mitochondrial genomes in phylogenetics and molecular evolutionary research, a better understanding of how asymmetric mitochondrial substitution gradients evolve would contribute key insights into how this gradient evolution may mislead evolutionary inferences, and how it may also be incorporated into new evolutionary models. Most snake mitochondrial genomes have an additional interesting feature, 2 nearly identical control regions, which vary among different species in the extent that they are used as origins of replication. Given the expanded sampling of complete snake genomes currently available, together with 2 additional snakes sequenced in this study, we reexamined gradient strength and CR usage in alethinophidian snakes as well as several lizards that possess dual CRs. Our results suggest that nucleotide substitution gradients (and corresponding nucleotide bias) and CR usage is highly labile over the approximately 200 m.y. of squamate evolution, and demonstrates greater overall variability than previously shown in primates. The evidence for the existence of such gradients, and their ability to evolve rapidly and converge among unrelated species suggests that gradient dynamics could easily mislead phylogenetic and molecular evolutionary inferences, and argues strongly that these dynamics should be incorporated into phylogenetic models.

Effects of neferine on cytosolic free calcium concentration in corpus cavernosum smooth muscle cells of rabbits

To study the relaxation mechanisms of neferine (Nef) on the corpus cavernosum smooth muscle (CCSM), the CCSM cells from New Zealand White rabbits were cultured in vitro. [Ca(2+)](i) was measured by fluorescence ion digital imaging system (FIDIS), using Fluo-2/AM as a Ca(2+)-sensitive fluorescent indicator. Nef (0.1, 1 and 10 micromol l(-1)) had no effect on the resting [Ca(2+)](i) (P > 0.05). In the presence of extracellular Ca(2+) (2.5 mmol l(-1)), Nef (0.1, 1 and 10 micromol l(-1)) inhibited [Ca(2+)](i) elevation induced by high K(+) and phenylephrine (PE) in a concentration-dependent manner (P < 0.05). In calcium free solution containing egtaic acid (EGTA), Nef (0.1 micromol l(-1)) had no inhibitory effects on [Ca(2+)](i) elevation induced by PE (P > 0.05). However, Nef (1 and 10 micromol l(-1)) inhibited [Ca(2+)](i) elevation induced by PE (P < 0.05). These data suggest that Nef inhibited [Ca(2+)](i) in CCSM cells via blocking voltage-dependent Ca(2+) channel, alpha(1)-adrenoceptor-operated Ca(2+) channel and Ca(2+) release from intracellular Ca(2+) pool. This inhibitory action on [Ca(2+)](i) might be one of the relaxation mechanisms of Nef on the CCSM.

Enterobacter Bacteremia: Clinical Features, Risk Factors for Multiresistance and Mortality in a Chinese University Hospital

BACKGROUND

This study was performed to characterize the clinical features and to identify the risk factors for multiresistance and mortality in patients with Enterobacter bacteremia.

PATIENTS AND METHODS

A number of 126 patients with Enterobacter bacteremia in 1995-2004 at the Medical university-affiliated Hospital of Anhui, China were retrospectively analyzed.

RESULTS

Of the 126 cases of bacteremia, 81 (64.3%) patients were identified as nosocomial infection. The overall multiresistance rate was 45.2% (57/126). Multiresistance was associated with nosocomial infection, recent invasive procedure, previous third-generation cephalosporins therapy, prolonged perioperative prophylaxis, the species of Enterobacter (E. cloacae) and polymicrobial bacteremia in univariate analysis. In multivariate analysis, previous third-generation cephalosporins therapy (OR = 13.6, p = 0.007) and prolonged perioperative prophylaxis (OR = 6.4, p = 0.029) were the strong, independent risk factors for the multiresistance. The crude 30-day mortality rate was 39.7% (50/126). Mortality directly attributed to Enterobacter spp. was 32.5% (41/126), which was significantly associated with multiresistance, nosocomial infection, recent invasive procedure, and inadequately empirical therapy in univariate analysis. Multivariate analysis revealed that only nosocomial infection (OR = 3.292, p = 0.049) was independently associated with mortality. The survival curve showed that the inappropriate initial therapy group had a lower probability of survival than the appropriate therapy group in infection-related mortality (Log Rank, p = 0.0142).

CONCLUSION

Enterobacter is becoming increasingly important nosocomial pathogens. Nosocomial infection is a clinical risk factor tightly associated with multiresistance and worse outcome. More judicious use of third-generation cephalosporins may decrease the incidence of nosocomial multiresistant Enterobacter spp. in China.

Deep Impact: observations from a worldwide Earth-based campaign

On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics.

[Cloning and identification of an unknown gene encoding 10.6 kDa protein of Schistosoma japonicum]

OBJECTIVE

To screen a new schistosome vaccine candidate.

METHODS

Schistosoma japonicum adult cDNA library was screened using sera from immune rabbits vaccinated with irradiated cercariae and monoclonal antibodies against membrane antigen of S. japonicum schistosomula. Three different fragments of S. japonicum cDNA genes were cloned into pGEM-T vector. The sequences of the inserts were determined using an automatic DNA sequencer and were analysed using Blast program. One of the unknown genes (B8) was selected and its ORF sequence (291 bp) was subcloned into eukaryotic expression vector. The recombinant plasmids were identified by restrictive enzymes and PCR amplification. The positive recombinant plasmids (pBK/SjB8) were transformed into host bacteria XL1-blue, and were then induced by IPTG for expression. SDS-PAGE and Western blotting analysis of total cellular protein from the bacteria were performed to detect the gene products.

RESULTS

The results demonstrated that ORF of SjB8 gene was subcloned into the plasmid pBK-CMV and could express as fusion protein in XL1-blue. The results of SDS-PAGE and Western-blot also showed that the molecular weight of the fusion protein with 3 kDa beta-galactosidase was approximately 13.6 kDa and the actual molecular weights of the SjB8 was 10.6 kDa. The expressed fusion product of pBK/Sj-B8 could be recognized by immune serum and McAb.

CONCLUSION

A new gene of S. japonicum vaccine candidate (SjB8) was cloned into eukaryotic expression vector pBK-CMV and could express 10.6 kDa schistosome protein. The results provide foundation for further study of the protein for its possibility as candidate vaccine.

[Enantiomeric separations of 1-1,2,4-triazole compounds by micro-high performance liquid chromatography]

The enantiomeric separations of sixteen novel 1-1,2,4-triazole chiral compounds were investigated by micro-HPLC with a 200 mm x 100 microns i.d. capillary chiral OD column. The detection was performed at 223 nm. The mobile phase was a mixture of iso-propyl alcohol and n-hexane(20:80, V/V) at a flow rate of 30 microL/min and column head pressure of 6.9 MPa. Some of the enantiomers could be separated on baseline. In comparing with the separation results by the conventional HPLC method, the micro-HPLC method had the advantages of high-speed, economy, environmental friendliness etc. The effect of solute structure on enantio-selectivity was investigated and the chiral recognition mechanism was also discussed. It was found that the main separation mechanisms involve the pi-pi association and inclusion between the substituent R and the spiral pocket of OD-CSP.

Biomechanical evaluation of cervical spine instability after multiple level laminectomy

Four fresh human cervical spine specimens (C2-T1) were tested both intact and with C5-C6 laminectomies to evaluate the biomechanical effects of multiple level laminectomy. The loads applied to the specimens were physiological and clinically relevant motion patterns were simulated. The results showed that C5 vertical displacements increased by 83.33% in axial compression, 168.75% in flexion, 106.09% in extension, and 35.14% in left bending after C5-C6 laminectomies compared with intact specimens. The increased rates of C6 vertical displacements after laminectomy were slightly lower than C5. The anterior horizontal bulging of C5-6 discs increased by 29.69% in axial compression, 13.86% in flexion, 61.79% in extension, and 13.40% in left bending after laminectomy. The rotational angles of whole specimens had an increase of 15% after laminectomy. The strains in the anterior vertebral bodies and posterior laminae near the articular processes of C5 and C6 were increased significantly after laminectomy. The data indicated that multiple level laminectomy can lead to biomechanical instability of the cervical spine.

Studies on specific serological antigens in metacercariae and juveniles of Paragoniums westermani and its monoclonal antibodies

The polyclonal antibodies to juveniles of Paragoniums westermani (PwJ-PcAbs) from sera of Wistar rats infected with Paragoniums westermani (P.w.) were purified by Sephadex G 200 chromatography. Next the shared serological antigens of P.w. metacercaria and juveniles (PwMJ-SAg) from the crude antigens of the metacercariae (M-NS-Ag) were purified with immuno-affinity chromatography on cyanogen bromide-activated cross-linked Sepharose 4B beads coupled with PwJ-PcAbs. PwMJ-SAg, a group of glycoprotein molecules shown by the staining test, were specific serological antigens of P.w. metacercariae and juveniles, identified by the immunoabsorb test and immunoelectrophoresis. By SDS-PAGE, PwMJ-SAg were fractionated to seven bands, including major bands A (27.5 K) and Bi (19.5 K), the two major serological antigen molecules. 20 sera samples from the patients with the nonpulmonary type of P. w. paragonimiasis were detected using PwMJ-SAg and M-NS-Ag by Dot-ELISA, and the difference of sensitivity between two antigens was highly statistically significant (P less than 0.001). BALB/c mice, in the early stage of infection with P. w. metacercaria, were immunized with PwMJ-SAg. The spleen cells of the mice were isolated and fused with SP2/o, a murine myeloma cell line. After three subclonal cultures, eight cell lines secreting monoclonal antibodies (McAbs) to PwMJ-SAg were prepared from 384 wells of hybridoma cells. All McAbs were IgG1 subclass.