[The application value of metagenomic next-generation sequencing technology in diagnosis and treatment of pulmonary infection in immunocompromised patients]

Objective: To evaluate the application value of metagenomic next-generation sequencing (mNGS) in the diagnosis and treatment of pulmonary infection in immunocompromised patients. Methods: A total of 78 patients with immunocompromised pulmonary infection [55 males and 23 females, aged (50.3±16.9) years] and 61 patients with non-immunocompromised pulmonary infection [42 males and 19 females, aged (63.6±15.9) years] in the Intensive Care Unit of the First Medical Center of College of the Pulmonary & Critical Care Medicine, Chinese PLA General Hospital from November 2018 to May 2022 were retrospectively selected. Patients in both groups received bronchoalveolar lavage fluid (BALF) mNGS and conventional microbiological tests (CMTs) while clinically diagnosed with pulmonary infection. The diagnostic positive rate, pathogen detection rate and clinical coincidence rate of the two methods were compared. At the same time, the difference of adjustment rate of anti-infective treatment strategy based on the results of mNGS detection was compared between the two groups. Results: The positive rates of mNGS in patients with pulmonary infection were 94.9% (74/78) and 82.0% (50/61) in the immunocompromised group and the non-immunocompromised group, respectively. The positive rates of CMTs in patients with pulmonary infection were 64.1% (50/78) and 75.4% (46/61) in the immunocompromised group and the non-immunocompromised group, respectively. The positive rates of mNGS and CMTs in patients with pulmonary infection in immunocompromised group showed a statistically significant difference (P<0.001). The detection rates of mNGS in the immunocompromised group for pneumocystis jirovecii and cytomegalovirus were 41.0% (32/78) and 37.2% (29/78), respectively, and the detection rates of Klebsiella pneumoniae, chlamydia psittaci and Legionella pneumophila were 16.4% (10/61), 9.8% (6/61) and 8.2% (5/61) in the non-immunocompromised patients, respectively, which were higher than those of CMTs [1.3% (1/78), 7.7% (6/78), 4.9% (3/61), 0 and 0] (all P<0.05). In the immunocompromised group, the clinical coincidence rates of mNGS and CMTs and were 89.7% (70/78) and 43.6% (34/78), respectively, with a statistically significant difference (P<0.001). In the non-immunocompromised group, the clinical coincidence rates of mNGS and CMTs were 83.6% (51/61) and 62.3% (38/61), with a statistically significant difference (P=0.008). In the immunocompromised group, according to the results of the etiology of mNGS, the adjustment rate of anti-infection treatment strategy was 87.2% (68/78), while in the non-immunocompromised group, the adjustment rate of anti-infective treatment strategy was 60.7% (37/61), with a statistically significant difference (P<0.001). Conclusion: In patients with immunocompromised pulmonary infection, mNGS has more advantages than CMTs in diagnostic positive rate, diagnosis rate of mixed infection, pathogen detection rate and guidance of anti-infection treatment strategy adjustment, which is worthy of clinical promotion and application.

The value of microbiology rapid on-site evaluation of sepsis caused by pulmonary infection

OBJECTIVE

This study aims to evaluate the value of microbial rapid on-site evaluation (M-ROSE) of sepsis, and septic shock caused by pulmonary infection.

PATIENTS AND METHODS

Thirty-six patients with sepsis and septic shock due to hospital-acquired pneumonia were analyzed. Accuracy and time were compared with M-ROSE, traditional culture, and next-generation sequencing (NGS).

RESULTS

A total of 48 strains of bacteria and 8 strains of fungi were detected by bronchoscopy in 36 patients. The accuracy rate of bacteria and fungi was 95.8% and 100%, respectively. M-ROSE took an average of 0.34±0.01 hours, much faster than NGS (22h±0.01 h, p<0.0001) and traditional culture time (67.50±0.91 h, p<0.0001).

CONCLUSIONS

M-ROSE may quickly identify common bacteria and fungi, so it may be a useful method for the etiological diagnosis of sepsis and septic shock caused by pulmonary infection.

[Analysis of brain volume asymmetry and clinical application in patients with temporal lobe epilepsy with hippocampal sclerosis based on automatic brain segmentation]

Objective: To analyze whole brain structural volume asymmetry in temporal lobe epilepsy with hippocampal sclerosis (TLE-HS) using automated brain segmentation technology, and to investigate the application value of this technology in the diagnosis of TLE-HS and the performance in determining the location the lateralization of epileptogenic focus. Methods: Twenty-eight patients with TLE-HS were enrolled in the First Affiliated Hospital of Zhengzhou University from April 2019 to October 2020, including 13 females and 15 males, aged ranged from 18 to 63 (30±12) years, and these patients were divided two group according to the epilepsy lateralization, left TLE-HS(LTLE-HS) group (n=11), right TLE-HS(RTLE-HS) group (n=17) and 28 normal controls [aged ranged from 18 to 49 (29±10) years]. All of these subjects underwent three-dimensional T₁ weighted image (3D T₁WI). The differences of brain structure and volumes in LTLE-HS, RTLE-HS and normal controls group were retrospectively analyzed, and Pearson's correlation coefficient was used to evaluate the left and right volume correlations, and effect size was used for evaluating the differences in left and right volume averages. The asymmetry index (AI) of the left and right lateral volumes in each group was also calculated and compared among the three groups. Results: Standard volumes of all structures within the brain were asymmetric in the normal controls, LTLE-HS, and RTLE-HS groups, with smaller volumes of ipsilateral hippocampus than contralateral hippocampus in both the LTLE-HS and RTLE-HS groups(0.20%±0.03% vs 0.24%±0.02%,0.21%±0.03% vs 0.25%±0.02% respectively;both P<0.001), and smaller volumes of gray and white matter of the ipsilateral temporal lobe than contralateral in the LTLE-HS group(4.41%±0.38% vs 5.01%±0.43%,1.83%±0.22 % vs 2.22%±0.14%;both P<0.001). There was a moderate to strong linear correlation (0.553<r<0. 964,all P<0.05) between left and right lateral volumes in the normal controls, LTLE-HS, and RTLE-HS groups. All three groups showed the largest effect sizes in the cingulate gyrus (The effect sizes were 3.07, 4.85 and 4.22 in control, LTLE-HS and RTLE-HS, respectively.). The AI values of the hippocampus, temporal lobe gray matter, and temporal lobe white matter were statistically different among the three groups (-1.48±8.64 vs 15.91±10.15 vs -17.59±10.00, 7.46±2.67 vs 12.67±6.67 vs 3.67±6.15, 6.53±3.71 vs 19.91±9.85 vs 1.57±8.38;all P<0.001). Conclusion: Volumetric measurements by automated brain segmentation techniques can play an important role in preoperative assessment of TLE, and the asymmetry of brain volume may be of value in determining the localization and extent of the epileptogenic focus.

[Study on the relationship between nonalcoholic fatty liver disease and hepatocellular carcinoma in patients with prior hepatitis B virus infection]

Objective: To explore the role of nonalcoholic fatty liver disease (NAFLD) in the development of hepatocellular carcinoma (HCC) in patients with prior hepatitis B virus infection (HBsAg-negative and anti-HBC-positive). Methods: 1605 hospitalized patients who were first diagnosed with HCC at Nanfang Hospital between 2015 to 2017 were retrospectively studied. Patients who developed HCC on the basis of active HBV infection (HBsAg-positive, anti-HBc positive) were used as control. Multivariate logistic regression model was used to analyze the relationship between NAFLD and HCC in patients with prior hepatitis B virus infection. Results: Among HCC patients with both HBsAg and anti-HCV negative, the proportion of prior HBV infection accounted for 86.7%. NAFLD prevalence was higher in patients with HCC based on prior HBV infection than active HBV infection (19.7% vs. 8.5%, P < 0.001). After adjusting for gender, age, hypertension, alanine aminotransferase, and liver cirrhosis, patients with HCC based on prior HBV infection were more likely to develop NAFLD (OR: 2.29, 95% CI: 1.40-3.74), and this phenomenon was observed only in patients with non-cirrhosis (OR: 5.26, 95% CI: 2.53-10.96) and aged≥50 years (OR: 2.36, 95% CI: 1.33-4.20). Conclusion: NAFLD may be a risk factor for HCC in a previously infected patients with HBV, especially in non-cirrhotic and population aged≥50 years.

Is there only one equilibrium configuration for spontaneous bending of liquid crystal elastomer circular plates with free edges?

In this paper, the spontaneous bending of a liquid crystal elastomer (LCE) circular plate under light illumination is investigated. The large bending deformation configurations for the LCE circular plate with free edges are obtained by minimizing the potential energy. It is found that for an LCE circular plate with random distribution of liquid crystal molecules, if the light intensity is small, there is only one equilibrium configuration for bending of the LCE circular plate. However, when the light intensity reaches a critical value, the circular plate will buckle and there will be three possible equilibrium configurations. On the other hand, for an LCE circular plate with uniform orientation of liquid crystal molecules, the strain induced by light is anisotropic, and there is only one equilibrium configuration. In addition, bending shapes of the LCE circular plate depend on its thickness. These results may be useful for designing light-driven LCE devices.

[Higher proportion of hepatitis B-related hepatocellular carcinoma combined with metabolic diseases in patients receiving antiviral therapy]

Objective: To investigate the proportion of hepatitis B-related hepatocellular carcinoma (HCC) patients who have received antiviral therapy and compare the clinical characteristics of HCC patients who have received antiviral therapy with those who have not received antiviral therapy. Methods: Data of 2590 newly diagnosed hepatitis B-related HCC cases who were hospitalized in Nanfang Hospital from 2015 to 2017 were collected. Two independent sample t-tests, Mann-Whitney U test, and χ(2) test were used to compare the clinical characteristics of hepatitis B-related HCC patients who had received antiviral therapy and those who had not received antiviral therapy. Propensity score was used to match some clinical characteristics of the two groups of patients, and the differences in clinical characteristics of the two groups of patients after matching were further compared. Patients with HCC who had not received antiviral therapy were used as reference, and then the clinical characteristics of HCC patients who had received antiviral treatment were analyzed using multivariate logistic regression. Results: Among the 2 590 patients with hepatitis B-related HCC, only 18.10% of patients had received antiviral therapy, while 82.20% of patients who did not receive antiviral therapy met the treatment criteria. HCC patients who had received antiviral therapy were older (P < 0.05), had a higher proportion of liver cirrhosis (P < 0.001), and lower levels of platelets and alanine aminotransferases and smaller maximum tumor diameter (P < 0.001). In terms of metabolic disease, patients who had received antiviral treatment had higher prevalence of diabetes (14.50% vs. 7.70%, P < 0.001), hypertension (16.60% vs. 11.20%, P < 0.05), obesity (28.50% vs. 22.30%, P < 0.05), overweight (53.80% vs. 43.50%, P < 0.001) and non-alcoholic fatty liver disease (18.30% vs.8.00%, P < 0.001). After matching other different clinical characteristics, the prevalence of diabetes, hypertension, and non-alcoholic fatty liver disease in patients who received antiviral therapy was still higher than that of patients who did not receive antiviral therapy (14.50% vs. 9.80%, P < 0.05; 16.60% vs. 10.20%, P < 0.05; 18.30% vs. 7.00%, P < 0.001). Multivariate logistic regression analysis showed that HCC patients who had received antiviral therapy had a higher risk of developing non-alcoholic fatty liver disease (OR: 2.054, 95% CI: 1.404~3.004) than those who had not received antiviral therapy. Conclusion: Among patients with hepatitis B-related HCC, the proportion of patients who have received antiviral therapy is significantly low (under 20%), which suggests that the popularization and promotion of antiviral therapy has a long way to go. Compared with HCC patients who have not received antiviral therapy, the proportion of HCC patients who have received antiviral therapy combined with metabolic diseases is higher; therefore, it is necessary to pay more attention to the role of metabolic factors in the pathogenesis of hepatitis B-related HCC.

[Prevalence and risk factors of nonalcoholic fatty liver disease in patients with chronic hepatitis B receiving antiviral therapy]

Objective: To investigate the prevalence and risk factors of non-alcoholic fatty liver disease(NAFLD) in patients with chronic hepatitis B(CHB) receiving antiviral treatment. Methods: The cross-sectional study included 3 477 cases with CHB who received antiviral therapy. The prevalence of NAFLD was investigated, and then the risk factors were screened and analyzed by stepwise regression method in CHB patients with NAFLD as the dependent variable and the related influencing factors as independent variables. Results: The prevalence of NAFLD was 24.1% in CHB patients who received antiviral therapy. After adjusting for age and gender, central obesity (OR: 7.44, 95%CI: 6.06 ~ 9.14), hypertension (OR: 1.74, 95%CI: 1.51 ~ 2.20), and triglyceride (OR: 1.52, 95%CI: 1.18 ~ 1.96) were positively associated with NAFLD, and cirrhosis was negatively associated with NAFLD (OR: 0.42, 95%CI: 0.34 ~ 0.53). Patients with long-term antiviral therapy had increased risk of NAFLD. Conclusion: A significant proportion of CHB patients receiving antiviral therapy have suffered from NAFLD. Therefore, CHB patients receiving long-term antiviral treatment should pay more attention to the prevalence of NAFLD.

Approximate and explicit expression of optical forces and pull-in instability of a silicon nano-optomechanical device

Nano-optomechanical systems actuated by optical forces enable many interesting scientific and technological applications. They are vulnerable to the effects of surface stress and Casimir forces. Therefore, calculation of optical forces is essential for the reliability applications of these advanced devices. In this paper, an approximate and explicit expression is developed for the evaluation of the optical force existing between a waveguide and a substrate through the effective refractive index. The influences of surface stress and Casimir forces on the pull-in instability of a silicon nano-optomechanical device actuated by optical forces are investigated. It is found that if neglecting the effect of surface stress, the maximum size, which indicates the device can be safely fabricated, will be over-predicted. The surface stress reduces the critical optical power and its effect is more significant for a slender waveguide.

[Prevalence of diabetes and its associated factors in Blang ethnic adults]

Objective: To investigate the prevalence and associated risk factors of diabetes and prediabetes in Blang ethnic adults in Menghai county. Methods: A cross-sectional survey including 3 365 Blang ethnic adults (aged 18 and above from 5 administrative villages) was conducted from February 2017 to March 2017 in Menghai county. A questionnaire, physical examination, and blood assays were included in the survey. Finally, a total of 3 237 adults with complete data were selected into this analysis. Results: The standardized prevalence of diabetes and prediabetes in Blang ethnic adults were estimated based on the sixth national census in 2010. According to the 1999 WHO criteria, the overall standardized prevalence of diabetes and prediabetes were 8.5% (men: 10.2%, women: 6.8%) and 16.1% (men: 18.0%, women: 14.1%), in which the standardized prevalence of newly diagnosed diabetes among the total population was 7.3% (men: 8.7%, women: 5.8%). Multivariable multinominal logistic regression analyses showed that age, hypertension, hypertriglyceridemia, and central obesity were significantly positively associated with both diabetes and prediabetes, with the corresponding odds ratios of 1.74 and 1.37, 2.39 and 2.02, 2.30 and 1.34, 2.55 and 1.73, respectively. Conclusion: The prevalence of diabetes is relatively high in Blang ethnic adults in Menghai county. Improving knowledge of diabetes among the local population is one of key steps in the prevention of diabetes.

Electrostatic potential in a bent piezoelectric nanowire with consideration of size-dependent piezoelectricity and semiconducting characterization

Determining the electric potential in a bent piezoelectric nanowire (NW) is a fundamental issue of nanogenerators and nanopiezotronics. The combined influence of the flexoelectric effect, the semiconducting performance and the angle of atomic force microscope (AFM) tip has never been studied previously and will be investigated in this paper. The exact solution for the electric potential of a bent piezoelectric semiconductor NW is derived. The electric potential of the present model with consideration of flexoelectric effect varies along the length of the NW and is different from that of the classical piezoelectric model. Flexoelectric effect enhances but the semiconducting performance reduces the electric potential of the NW. In addition, it is found that if the angle of the AFM tip reaches 30°, the error of the electric potential obtained from the model ignored the effect of the angle of the AFM tip is almost 16%, which is unacceptable.

Isolation and biological characteristics of multipotent mesenchymal stromal cells derived from chick embryo intestine

1. Over the past decade, rapid advancement in isolation methods for identifying markers of the once elusive intestinal stem cell (ISC) populations has laid the foundation for unravelling their complex interrelationships during homeostasis. Study on ISC in avian intestinal tissue might play a pivotal foundation for further studies on the epithelial-to-mesenchymal transition (EMT) in gastrointestinal disease and cell-based therapy as well as intestinal tissue engineering. 2. The following experiment isolated a population of fibroblast-like, plastic adhering cells derived from chick embryo intestine, showing a strong self-renewing and proliferative ability, which was maintained in vitro up to passage 25. The findings included growth characteristics, detected expression of cell surface markers and characterised the capability of these cells to differentiate towards the osteogenic, adipogenic, and chondrogenic cell lineages. 3. RT-PCR analysis showed that these cells from chick embryos expressed mesenchymal stromal cell markers CD44, CD90 and VIMENTIN as well as ISC-specific genes LGR5, MI1, SMOC2, BMI1, and HOPX. Immunofluorescence and flow cytometry confirmed this biology characterisation further. 4. In conclusion, cells were isolated from the intestine of 18-day-old chicken embryos that exhibited the biological characteristics of mesenchymal stromal cells as well as markers of intestinal stem cells. Our findings may provide a novel insight for in vitro cell culture and characteristics of ISCs in avian species, which may also indicate a benefit for obtaining cell source for intestinal tissue engineering as well as cell-based investigation for gastrointestinal disease and treatment.

[Radiological analysis of coronal and sagittal spinopelvic parameters in patients with degenerative lumbar kyphoscoliosis]

Objective: To review and compare radiological parameters between degenerative lumbar kyphoscoliosis (DLKS) and degenerative lumbar kyphosis (DLK), and analyze the relationships between coronal and sagittal deformities and compensatory mechanisms of sagittal balance. Methods: A total of 82 patients with lumbar degenerative deformities were enrolled for our radiographic study at Department of Spinal Surgery, Peking University People's Hospital from January 2016 to May 2017. These patients were divided into two groups: DLKS group (39 patients) with lumbar coronal and sagittal deformities, and DLK group (43 patients) just with lumbar sagittal deformity. Complete spinopelvic radiographic parameters were compared. Results: The Cobb angle and lumbar lordosis of DLKS group were (23.0±11.8)° and (18.2±12.1)°, while the lumbar lordosis of DLK group was (20.4±10.2)°. In DLKS group, Cobb angle had correlations with lumbar lordosis(r=-0.338, P=0.035), and central sacral vertical line distance had significant correlations with thoracolumbar junctional angle (r=0.488, P=0.002) . Moreover, no significant differences of all sagittal spinopelvic parameters were found between two groups (P>0.05). In DLKS group, significant correlations between lumbar lordosis and sacral slope (r=0.617, P=0.000), and correlations between lumbar lordosis and thoracic kyphosis(r=-0.363, P=0.023) were observed. In DLK group, lumbar lordosis showed significant correlations with thoracic kyphosis(r=-0.341, P=0.025) and sacral slope (r=0.772, P=0.000). According to Nash-Moe grading scale of apical vertebral rotation, 10 patients were with Ⅰ-Ⅱ grade while 29 patients with Ⅲ-Ⅴ grade in DLKS group. Conclusions: Both as typical lumbar degenerative deformities, there are some correlations between scoliosis and kyphosis. However, coronal scoliosis may not influent sagittal morphological parameters for DLKS patients. Thoracic curve changes and pelvic backtilt are both important for maintaining the sagittal balance in patients with degenerative lumbar kyphoscoliosis.

Biological characterization of liver fatty acid binding gene from miniature pig liver cDNA library

Liver fatty acid binding proteins (L-FABP) are a family of small, highly conserved, cytoplasmic proteins that bind to long-chain fatty acids and other hydrophobic ligands. In this study, a full-length enriched cDNA library was successfully constructed from Wuzhishan miniature pig, and then the L-FABP gene was cloned from this cDNA library and an expression vector (pEGFP-N3-L-FABP) was constructed in vitro. This vector was transfected into hepatocytes to test its function. The results of western blotting analysis demonstrated that the L-FABP gene from our full-length enriched cDNA library regulated downstream genes, including the peroxisome proliferator-activated receptor family in hepatocytes. This study provides a theoretical basis and experimental evidence for the application of L-FABP for the treatment of liver injury.

Reduced cortisol in the absence of bacterial infection in patients with hepatitis B virus cirrhosis

In liver cirrhosis with bacterial infection, hepatoadrenal syndrome has been described recently as a progressive impairment in the adrenocortical reserve, with deficient production or action of glucocorticoids resulting in adrenal insufficiency. The aim of this study was to explore the characteristics of cortisol in hepatitis B virus (HBV) cirrhosis patients in the absence of bacterial infection. Fasting peripheral venous blood samples were collected from 107 patients with HBV cirrhosis in the absence of bacterial infection and 18 patients with chronic hepatitis B (CHB) infection at 7 a.m. in the morning. The carbohydrate, cortisol-binding globulin, routine chemistry, liver function, and hepatitis B indicators were tested, and free cortisol was calculated. Cortisol (COR) levels were 18.72 ± 6.60 μg/dL in the CHB group and 14.20 ± 7.55 μg/dL in the HBV cirrhosis group (P = 0.002). COR levels were 15.11 ± 5.56, 14.88 ± 6.96, and 12.68 ± 8.36 μg/dL in Child-Pugh class A, B, and C cirrhotic patients, respectively (P = 0.006). Adrenocorticotropic hormone levels were 35.42 ± 24.49, 26.57 ± 15.72, and 19.65 ± 10.72 pg/mL in Child-Pugh class A, B, and C cirrhotic patients, respectively (P = 0.000). Patients with HBV cirrhosis had significantly lower serum COR levels compared with those of CHB patients, even if they are in the absence of bacterial infection. COR levels negatively correlated with Child-Pugh scores. The hypothalamic-pituitary-adrenal axis might be damaged in patients with HBV cirrhosis.

Coupled ferroelectric polarization and magnetization in spinel FeCr2S4

One of the core issues for multiferroicity is the strongly coupled ferroelectric polarization and magnetization, while so far most multiferroics have antiferromagnetic order with nearly zero magnetization. Magnetic spinel compounds with ferrimagnetic order may be alternative candidates offering large magnetization when ferroelectricity can be activated simultaneously. In this work, we investigate the ferroelectricity and magnetism of spinel FeCr₂S₄ in which the Fe²⁺ sublattice and Cr³⁺ sublattice are coupled in antiparallel alignment. Well defined ferroelectric transitions below the Fe²⁺ orbital ordering termperature T_oo = 8.5 K are demonstrated. The ferroelectric polarization has two components. One component arises mainly from the noncollinear conical spin order associated with the spin-orbit coupling, which is thus magnetic field sensitive. The other is probably attributed to the Jahn-Teller distortion induced lattice symmetry breaking, occuring below the orbital ordering of Fe²⁺. Furthermore, the coupled ferroelectric polarization and magnetization in response to magnetic field are observed. The present work suggests that spinel FeCr₂S₄ is a multiferroic offering both ferroelectricity and ferrimagnetism with large net magnetization.

Ferroelectricity and ferromagnetism of La(0.5)Lu(0.5)Ni(0.5)Mn(0.5)O(3) thin films on Nb:SrTiO(3) substrates

Epitaxial orthorhombic La(0.5)Lu(0.5)Ni(0.5)Mn(0.5)O(3) (LLNMO) thin films deposited on Nb:SrTiO(3) (NSTO) substrates are prepared by pulsed laser deposition and their ferroelectricity and magnetism are investigated using various techniques. It is revealed that the as-prepared thin films are ferromagnetic (FM) insulators. The FM transition occurring at ∼ 125 K is evidenced by the well defined hysteresis at low temperature, with a saturated magnetic moment as high as 1.8 µ(B)/f.u. at ∼ 5 K. A reversible ferroelectric polarization of ∼ 0.2 µC cm(-2) below ∼ 140 K is also observed. The magnetism can be understood by the FM ordering associated with a partially ordered major Ni(2 +)-Mn(4 +) plus minor Mn(3+)-Ni(3+) configuration, while the ferroelectricity is argued to originate from the A-site disordering of La(3+) and Lu(3+).

Competition between quantum fluctuations and antiferroelectric order in Ru-doped Sr(0.8)Ca(0.2)Ti(1-x)Ru(x)O(3)

The competition between quantum fluctuations and the antiferroelectric state in Sr(0.8)Ca(0.2)Ti(1-x)Ru(x)O(3) is investigated by measuring the low-temperature dielectric permittivity and by Raman spectroscopy. We demonstrate the significant impact of quantum fluctuations on the stability of the antiferroelectric polar order. It is revealed that the structural phase transitions can be modified by the quantum fluctuations, enhancing the stability of the high-symmetry phase and suppressing the antiferroelectric transitions. More importantly, a quantum antiferroelectric state, exhibiting similar behavior as the quantum ferroelectric state in terms of dielectric response, is identified. In addition, the effect of quantum fluctuations on the increasing permittivity at low temperature is also discussed.

Electric field induced collapse of the charge-ordered phase in manganites

The colossal electroresistance in manganites accompanies the insulator-to-metal phase transition induced by the electric field. A phenomenological phase transition model is proposed to study this electric field induced collapse of the charge-ordered phase. The hysteresis of the phase transition is well explained using the effective medium approximation. The volume fraction of the metallic region at the metal-to-insulator transition point is estimated as 30%.

Association of T-786C eNOS gene polymorphism with increased susceptibility to acute chest syndrome in females with sickle cell disease

Acute chest syndrome (ACS) is a life-threatening complication of sickle cell disease (SCD). A retrospective study was performed to evaluate the role of endothelial nitric oxide synthase (eNOS) gene polymorphisms (E298D and T-786C) in African-American SCD patients. The D298 allele showed no association; the C-786 allele showed a statistically significant association (P = 0.0061) in female ACS cases. Multiple logistic regression analysis showed that relative risk of ACS was 8.695 (P = 0.0076, 95% confidence interval 1.761-42.920) for female carriers of C-786. eNOS T-786C is a gender-specific genetic modifier that is associated with increased susceptibility to ACS in female SCD patients.

Expression and characterization of the terminal heme synthetic enzymes from the hyperthermophile Aquifex aeolicus

The terminal two heme biosynthetic pathway enzymes, protoporphyrinogen oxidase and ferrochelatase, of the hyperthermophilic bacterium Aquifex aeolicus have been expressed in Escherichia coli, purified to homogeneity, and biochemically characterized. Ferrochelatase and protoporphyrinogen oxidase of this organism are both monomeric, as was found for the corresponding enzymes of Bacillus subtilis. However, unlike the B. subtilis proteins, both A. aeolicus enzymes are membrane-associated. Both proteins have temperature optima over 60 degrees C. This is the first demonstration of functional heme biosynthetic enzymes in an extreme thermophilic bacterium.

[Effect of reduqing on HL-60 cells in secreting tumor necrosis factor alpha production and on TNF alpha converting enzyme mRNA expression]

OBJECTIVE

To explore the molecular mechanism of inhibiting effects of Reduqing on the release of tumor necrosis factor alpha (TNF alpha).

METHODS

Using cytobiologic and molecular biologic technique to observe the effects of Reduqing on HL-60 cells in producing inflammatory cytokine secreting TNF alpha (sTNF alpha) and on mRNA expression of TNF alpha converting enzyme (TACE).

RESULTS

(1) Reduqing, diluted in ratio 1:30, could effectively inhibit the increased HL-60 production of sTNF-alpha induced by lipopolysaccharides (LPS); (2) Although no obvious effect on TACE was shown when Reduqing was applied alone on HL-60 cells, there was evident inhibitory effect of Reduqing on TACE mRNA expression enhancement induced by LPS.

CONCLUSION

Reduqing could have the double inhibitory effects both on sTNF-alpha production and on the gene expression of its key enzyme, i.e. TACE stimulated by LPS, suggesting that it might be a hopeful and excellent natural TACE inhibitor.

Ferrochelatase at the millennium: structures, mechanisms and [2Fe-2S] clusters

Ferrochelatase (E.C. 4.99.1.1, protoheme ferrolyase) catalyzes the insertion of ferrous iron into protoporphyrin IX to form protoheme (heme). In the past 2 years, the crystal structures of ferrochelatases from the bacterium Bacillus subtilis and human have been determined. These structures along with years of biophysical and kinetic studies have led to a better understanding of the catalytic mechanism of ferrochelatase. At present, the complete DNA sequences of 45 ferrochelatases from procaryotes and eucaryotes are available. These sequences along with direct protein studies reveal that ferrochelatases, while related, vary significantly in amino acid sequence, molecular size, subunit composition, solubility, and the presence or absence of nitric-oxide-sensitive [2Fe-2S] cluster.

Simultaneous measurement of pure curvature and twist distribution fields by a five-aperture shearing and two-fourier filtering technique

A five-aperture shearing and two-Fourier filtering technique to measure simultaneously pure curvature and twist distribution fields of a deformed object is proposed. In this method the slope fringes that are contained in the patterns of curvature and twist fringes can be completely eliminated. Thus patterns of pure curvature and twist fringes with a good contrast can be obtained. A theoretical analysis and experimental results are given.

Purification, crystallization and preliminary X-ray analysis of Drosophila melanogaster ferrochelatase

Ferrochelatase (protoheme ferrolyase, E.C. 4.99.1.1), the terminal enzyme in the heme biosynthetic pathway, catalyzes the insertion of ferrous iron into protoporphyrin IX to form protoheme. In eukaryotes, the protein is associated with the inner surface of the inner mitochondrial membrane, and in higher animals the enzyme contains a [2Fe-2S] cluster. This cluster is highly sensitive to NO and is coordinated by four Cys residues whose spacing in the primary sequence is unique. Ferrochelatase from Drosophila melanogaster has been expressed in Escherichia coli with an amino-terminal six-histidine tag and purified to homogeneity. The protein has been crystallized with the [2Fe-2S] cluster intact. The crystals belong to space group I422, with unit-cell dimensions a = b = 158.1, c = 171.2 A and two molecules in the asymmetric unit, and diffract to 3. 0 A resolution.

Evidence that the fourth ligand to the [2Fe-2S] cluster in animal ferrochelatase is a cysteine. Characterization of the enzyme from Drosophila melanogaster

In a previous study, site-directed mutagenesis experiments identified three of the four ligands to the [2Fe-2S] cluster in animal ferrochelatase as conserved cysteines in the COOH-terminal extension, Cys-403, Cys-406, and Cys-411 in human ferrochelatase (Crouse, B. R., Sellers, V. M., Finnegan, M. G., Dailey, H. A. & Johnson, M. K. (1996) Biochemistry 35, 16222-16229). The nature of the fourth ligand was left unresolved, and spectroscopic studies raised the possibility of one noncysteinyl, oxygenic ligand. In this work, we report two lines of evidence that strongly suggest the fourth ligand is a cysteine residue. Cysteine at position 196 in human recombinant ferrochelatase when changed to a serine results in an inactive enzyme that is lacking the [2Fe-2S] cluster. Furthermore, whole cell EPR studies demonstrate that in the C196S mutant the cluster fails to assemble. Additionally, the cloning and expression of Drosophila melanogaster ferrochelatase has allowed the identification, by EPR and UV-visible spectroscopy, of a [2Fe-2S]2+ cluster with properties analogous to those of animal ferrochelatases. The observation that Drosophila ferrochelatase contains only four conserved cysteines at positions 196, 403, 406, and 411, is in accord with the proposal that these residues function as cluster ligands. In the case of the ferrochelatase iron-sulfur cluster ligands, NH2-Cys-X206-Cys-X2-Cys-X4-Cys-COOH, the position distant from other ligands may lead to a spatial positioning of the cluster near the enzyme active site or at the interface of two domains, thereby explaining the loss of enzyme activity that accompanies cluster degradation and reinforcing the idea that the cluster functions as a regulatory switch.

The effects of "huoxuequyu" decoction on lipid peroxidation in IUGR rats

The rats exposed to passive smoking were used as the animal model to further study the pathogenesis of IUGR and the effects of "Huoxuequyu" decoction. The results showed that the mean birth-weight of fetus and SOD activity of placenta and plasma in model rats were significantly reduced, and LPO levels of placenta and plasma were significantly increased. We found that the mean birth-weight and SOD activity in treated group were higher than that in model group, and LPO levels of placenta and plasma were lower in treated group than that in model group and there was no difference in SOD activity and LPO levels of placenta and plasma as well as the mean birthweight between treated group and control group, indicating that "Huoxuequyu" decoction can protect placenta and plasma against lipid peroxidation, and improve the blood circulation of uteroplacenta, thus contributing to the increase of the mean birth-weight.

Sinusitis and bronchial asthma in children

Sinus disease has been assumed to exist in children with respiratory tract allergies. We consecutively evaluated 375 patients (245 male, 130 female) with childhood onset asthma, between 5 and 15 years of age (mean 7.8 years of age). Abnormal Waters radiographs were found in 205 patients (54.7%) which included mucosal wall thickening greater than 6 mm (67.3%), complete opacification (22.9%) and air-fluid levels (9.8%). The level of immunoglobulin (Ig) E was found to be much higher in non-sinusitis asthmatic children than in asthmatic children with sinusitis (1207 IU/mL vs. 644 IU/mL). The IgG, IgA, IgM and erythrocyte sedimentation rate (ESR) values were not significantly different in the two groups. All patients were treated with antibiotics for 3 to 6 weeks. Five patients required surgical intervention after antibiotic treatment had little success. Streptococcus viridans was isolated from 4 patients following surgical aspirates and Peptostreptococcus anaerobius was isolated in only one patient. In conclusion, sinusitis in children may be an aggravating factor for chronic reactive lower airway disease. Optimal treatment may decrease the need of asthmatic medication.

[Hemophilus aphrophilus meningitis: report of one case]

Hemophilus aphrophilus, a gram negative, capnophilic slow growing bacillus, is a rarely recognized pathogen in meningitis and is most frequently seen in patients with either endocarditis or brain abscess. This article reported one case with Hemophilus aphrophilus meningitis. A 10-year-old boy presented at the emergency room with chief complaint of fever for 2 days and sudden onset of loss of consciousness. Hemophilus aphrophilus was isolated from the blood and cerebrospinal fluid. Aqueous penicillin and chloramphenicol were given for three weeks. The patient discharged without any sequelae. Three months later, fever and consciousness disturbance were noted again. No pathogen was isolated from the cerebrospinal fluid and blood culture this time, but CSF finding was consistent with bacterial meningitis. Aqueous penicillin and chloramphenicol were readministered for 30 days. The patient recovered smoothly. Because the patient had no history of CSF rhinorrhea or hypogammaglobulinemia, recurrence of the bacterial meningitis could be due to incomplete treatment during the first admission. Brain computed tomography (CT) done during the two admissions showed focal cortical enhancement in the fronto-temporo-parietal region. This is presumed to indicate infarction over these regions. The findings of brain CT are in accordance with the development of hemiplegia in the patient. It is still unknown, however, whether Hemophilus aphrophilus meningitis also causes a higher incidence of brain infarction, which was frequently noted in patients with Hemophilus influenzae meningitis.

[Limulus lysate activity of some organisms resided in oral cavity]

Gram-positive and Gram-negative bacteria resided in oral cavity have been investigated using Limulus Lysate Assay. The study showed that both kinds of organisms have Limulus Lysate Activity (LLA). The data from the present study indicated that various species of Gram-positive and Gram-negative bacteria possess different degrees of LLA. There is no significant difference of LLA between Gram-positive and Gram-negative bacteria.