Clinical value of quantitative parameters of MSCT in the diagnosis of occult femoral neck fractures.

To explore the clinical value of quantitative parameters of multi-slice computer tomography (MSCT) in the diagnosis of occult femoral neck fractures.The clinical data of 94 patients with suspected occult femoral neck fractures admitted to our hospital from April 2021 to April 2022 were selected for retrospective analysis, and they were divided into group A (accurate diagnosis, n = 63) and group B (non-occult femoral neck fractures, n = 31) according to the results of pathological and surgical diagnosis as the gold standard. All patients received MSCT examination to obtain quantitative parameters related to imaging, and receiver operator characteristic (ROC) curves were used to comprehensively evaluate the clinical value of quantitative parameters of MSCT in the diagnosis of occult femoral neck fractures.The quantitative parameters of MSCT in group A were overtly lower than those in group B (P < 0.05). The AUC value, Youden index and sensitivity of the combined detection were higher than those of single detection.The use of quantitative parameters of MSCT effectively reduces the missed diagnosis rate of occult femoral neck fractures, which could make an accurate diagnosis of the fracture type, as a basis for the formulation of clinical treatment plans.

[Quantifying direct N2O emissions from paddy fields during rice growing season in China: model and input data validation].

The models on direct N2O emissions from rice paddies under different water regimes developed by the authors were validated against field measurements in China reported in 2005-2007 and in other regions. In flooding rice paddies (F), N2O emission predicted by the model was consistent with previous reports in other regions. Under the water regime of flooding-midseason drainage-reflooding (F-D-F), the model developed in this study was comparable to that established by using worldwide database. The models also well fitted N2O emissions from rice paddies under the water regime of flooding-midseason drainage-reflooding-moisture but without waterlogging (F-D-F-M) in China. Consistency of rice production data derived from the database of this study with those reported in previous studies suggests that the model input data of rice production had high reliability. The input data showed that water management and nitrogen input regimes have greatly changed in rice paddies since the 1950s. During the 1950s-1970s, about 20%-25% of the rice paddy was continuous water logging, and 75%-80% under the water regime of F-D-F. Since the 1980s, about 12%-16%, 77% and 7%-12% of paddy fields were under the water regimes of F, F-D-F and F-D-F-M, respectively. Total N input during the rice growing season averaged 87.49 kg x hm(-2) in the 1950s and 224.64 kg x hm(-2) in the 1990s. Chemical N input during the rice growing season has increased from 37.4 kg x hm(-2) in the 1950s to 198.8 kg x hm(-2) in the 1990s, accounting for 43% and 88% of the seasonal total N inputs, respectively. Manure N input was applied at stable rate, ranging from 45.2 kg x hm(-2) to 48.2 kg x hm(-2) during the 1950s-1970s, but thereafter it decreased over time. The contribution of manure N to total N inputs has decreased from 52% in the 1950s to 9% in the 1990s. Crop residue N retained during the rice growing season has increased from 4.9 kg x hm(-2) in the 1950s to 6.3 kg x hm(-2) in the 1980s. A high spatial variation of nitrogen inputs during the rice growing season was found in the 1950s-1970s, while it was not pronounced in the 1980s-1990s. Overall, the results of this study suggest that the models could be used to quantify direct N2O emissions from rice paddies under various water regimes in China.

[Quantifying direct N2O emissions from paddy fields during rice growing season in China: model application].

Based on statistical analysis of field N2O measurements in rice paddies in China, the models on direct N2O emissions under different water regimes were established. After successes in model validation and input data verification, the models were used to quantify changes in direct N2O emissions from paddy fields during the rice growing season in mainland China between the 1950s and the 1990s. Due to increases in rice planting area and nitrogen input and changes in water regime, the models predicted that seasonal N2O-N emissions from rice paddies have increased from 9.55 Gg each year in the 1950s to 32.26 Gg N2O-N in the 1990s, which was accompanied by the increase in rice yield over the period 1950s-1990s. During the period 1950s-1990s, seasonal N2O-N emissions from rice paddies have increased, on average, at a rate of 6.74 Gg per decade. Seasonal N2O fluxes in rice paddies were estimated to be 0.32 kg x hm(-2) in the 1950s and 1.00 kg x hm(-2) in the 1990s, which accounted for 0.37% and 0.46% of the seasonal total N inputs, respectively. The uncertainties in N2O estimate were estimated to be 59.8% in the 1950s and 37.5% in the 1990s. Seasonal N2O emissions from rice paddies in the region of middle and lower Yangtze River contributed 51% -56% to its national total. In the 1990s, N2O emissions during the rice growing season accounted for 8%-11% of the reported annual total of N2O emissions from croplands in China, suggesting that paddy rice development could have contributed to mitigating agricultural N2O emissions in the past decades. However, seasonal N2O emissions would be increased given that saving-water irrigation and nitrogen inputs are increasingly adopted in rice paddies in China.

Decreased saliva secretion and down-regulation of AQP5 in submandibular gland in irradiated rats.

The molecular mechanisms of radiation-induced xerostomia remain unclear. The purpose of this study was to investigate the alterations of aquaporins (AQPs) and Na(+)/K(+)-ATPase in irradiated rat submandibular glands and to test the hypothesis that down-regulation of AQP5 expression in irradiated salivary glands is one of the mechanisms of radiation-induced xerostomia. Saliva from control and irradiated rat submandibular glands was analyzed. The mRNA level of AQP5 in the submandibular glands was assessed by semi-quantitative RT-PCR and in situ hybridization. The protein expression of AQP5, AQP1 and Na(+)/K(+)-ATPase was determined by Western blotting and immunohistochemistry. The body weight, submandibular gland weight, and saliva secretion of irradiated rats significantly decreased by 12, 24 and 32% on day 3 and 24, 16 and 38% on day 30 postirradiation, respectively. There was a significant increase in the protein concentration and osmolality of saliva in irradiated rats on days 3 and 30 postirradiation. However, there was no significant difference between irradiated and control rats in total saliva protein secretion. RT-PCR analysis showed that mRNA expression of AQP5 was significantly down-regulated by 37 and 51% in irradiated rats on days 3 and 30 postirradiation, respectively. Immunoblotting showed that the AQP5 protein level was decreased by 40 and 60% in irradiated glands, in contrast to the slight reductions of AQP1 and Na(+)/K(+)-ATPase proteins. Immunohistochemical analysis demonstrated that loss of AQP5 protein occurred throughout the irradiated glands, while no significant reduction was detected in AQP1 and Na(+)/ K(+)-ATPase labeling density. These results suggest that the preferential down-regulation of AQP5 with minor effects on AQP1 and Na(+)/K(+)-ATPase may contribute to radiation-induced salivary dysfunction.

[Experimental research on the effect of nanophase ceramics on osteoblasts functions].

In order to study the cytocompatibility of nanophase hydroxyapatite ceramic in vitro, we prepared hydroxyapatite by use of the wet chemistry techniques. The grain size of hydroxyapatite of interest to the present study was determined by scanning electron microscopy and atomic force microscopy with image analysis software. Primary culture of osteoblast from rat calvaria was established. Protein content, synthesis of alkaline phosphatase and deposition of calcium-containing mineral by osteoblasts cultured on nanophase hydroxyapatite ceramics and on conventional hydroxyapatite ceramics for 7, 14, 21 and 28 days were examined. The results showed that the average surface grain size of the nanophase and that of the conventional HA compact formulations was 55 (nanophase) and 780 (conventional) nm, respectively. More importantly, compared to the synthesis of alkaline phosphatase and deposition of calcium-containing mineral by osteoblasts cultured on nanophase was significantly greater than that on conventional ceramics after 21 and 28 days. The cytocompatibility was significantly greater on nanophase HA than on conventional formulations of the same ceramic.

[Differential expression of apoptosis-related gene induced by clinical and laboratory Mycobacterium tuberculosis strain in macrophages U937 revealed by oligonucleotide microarray].

Tuberculosis(TB) remains one of the major problems in global health. Macrophage (MPhi) apoptosis, induced by Mycobacterium tuberculosis (Mtb), is a cornerstone of effective innate microbial defense mechanism. Elucidation of the complex apoptosis-related gene expression may facilitate understanding the mechanism and regulation of macrophage apoptosis in response to Mtb, and contribute to developing novel measures to counter TB. DNA microarray containing 19,200 gene or gene fragments was used to compare the macrophage cell line U937 gene expression response to the clinical and laboratory Mtb infection. Northern blotting and RT-PCR were used to confirm the microarray results. Mtb H37Rv infection were found to downregulate the bcl-2, vitamin D receptor, interferon regulatory factor 3, cytochrome c oxidase, gene expression by 2-, 3-, 3-, 2.5-fold, respectively, while the clinical strain infection leads to upregulate the SOD2, SOD3, serine protease, toll-like receptor 2, signal transducer and activator (STAT1), hypoxia-inducible factor 22, 2.9-, 2.5-, 2.5-, 2.2-, 2.4-, 5.9-fold respectively. The findings suggest that the clinical strain infection tends to override the macrophage apoptosis by which the host attempt to limit the growth of the invader. The research on the complex factors network involved in the interaction will benefit the vaccine and novel drug target development.

[Biomechanical study of open bite treatment with tip forward bend].

OBJECTIVE: To verify whether it is effective to treat open bite cases with tip-forward bend. METHODS: Three-dimensional finite element (TDFE) models of the lower left central incisor and first molar were set up by means of CT. Stress distribution in root, PDL and alveolar bone, and the tendency of the tooth movement were obtained by calculation under different orthodontic forces. RESULTS: (1) The molar model revealed that the tensile stress concentration was at the distal cervix and the compressive stress concentration at mesial cervix. (2) The incisor model showed that the tensile stress was concentrated at apical tip and the compressive stress concentration was at the lingual side of the cervix. (3) The incisor had the tendency to elongate and move lingually. The molar tended to tip mesially and buccally. CONCLUSIONS: Arch wire with tip forward bend depends on the elongation and lingual movement of anterior teeth to treat open bite, but the anchorage molar will incline mesially further, which is not consistent with the mechanism to treat open bite.

[Cytocompatibility of nanophase hydroxyapatite ceramics].

OBJECTIVE: To evaluate the cytocompatibility of nanophase hydroxyapatite ceramics in vitro. METHODS: Hydroxyapatite (HA) was prepared via wet method. The grain size of the hydroxyapatite in the study was determined by scanning electron microscope and atomic force microscope with image analysis software. Primary osteoblast culture was established from rat calvaria. Cell adherence and proliferation on nanophase hydroxyapatite ceramics and conventional hydroxyapatite ceramics were examined at 1, 3, 5, 7 days. Morphology of the cells was observed by microscope. RESULTS: The average grain size of the nanophase and conventional HA was 55 nm and 780 nm, respectively. Throughout 7 days period, osteoblast proliferation on the HA was similar to that on tissue culture borosilicate glass controls, osteoblasts could attach, spread and proliferate on HA. However, compared to conventional ceramics, osteoblast proliferation on nanophase HA was significantly better after 1, 3, 5 and 7 days. CONCLUSION: Cytocompatibility of nanophase HA was significantly better than conventional ceramics.

Using a cDNA microarray to study cellular gene expression altered by Mycobacterium tuberculosis.

OBJECTIVE: To examine the global effects of Mycobacterium tuberculosis (M. tuberculosis) infection on macrophages. METHODS: The gene expression profiling of macrophage U937, in response to infection with M. tuberculosis H(37)R(a), was monitored using a high-density cDNA microarray. RESULTS: M. tuberculosis infection caused 463 differentially expressed genes, of which 366 genes are known genes registered in the Gene Bank. These genes function in various cellular processes including intracellular signalling, cytoskeletal rearrangement, apoptosis, transcriptional regulation, cell surface receptors, cell-mediated immunity as well as a variety of cellular metabolic pathways, and may play key roles in M. tuberculosis infection and intracellular survival. CONCLUSIONS: M. tuberculosis infection alters the expression of host-cell genes, and these genes will provide a foundation for understanding the infection process of M. tuberculosis. The cDNA microarray is a powerful tool for studying pathogen-host cell interaction.

[Rearrangement and altered expression of actin in macrophages induced by Mycobacterium tuberculosis].

OBJECTIVE: To investigate the effect of M. tuberculosis infection on actin in host-cells. METHODS: The form and distribution of fibrous actin and changes of actin expression were observed by confocal microscopy and Western blot analysis in macrophages infected with either M. tuberculosis H(37)R(a) or H(37)R(v) at 6 h, 12 h and 24 h after infection. Non-infected macrophages or macrophages treated with dead M. tuberculosis H(37)R(v) served as controls. RESULTS: F-actin aggregated and the actin expression was suppressed in macrophages infected with H(37)R(a) or H(37)R(v), and the effect appeared earlier in cells infected by the virulent H(37)R(v) strain than in cells infected by the avirulent H(37)R(a) strain. In macrophages treated with the dead H(37)R(v), actin was not affected. CONCLUSION: The results suggest that in the process of infection, M. tuberculosis evades the bactericidal mechanisms possibly by secretion of certain proteins or factors which affect the host-cell actin.

[Effects of Mycobacterium tuberculosis infection on the transcriptional expression of human macrophage gene encoding ion channels and related regulatory elements].

Expression microarray was employed in this study to investigate whether the ion channels and their regulatory elements encoding genes participate in the immune response to Mycobacterium tuberculosis infection. The results of a virulent strain were compared with those of the clinically isolated strains. The data demonstrate that K(+), Na(+), Ca(2+) and Cl(-) channels and their regulatory elements, such as the G protein, receptor and second messenger, protein kinase and protein phosphatase were involved in the immune reaction. The clinical strain affected more types of ion channels and respective regulatory elements. The data provides clues for further scrutiny into the role of ion channels and related elements in the interaction between Mycobacterium tuberculosis and host macrophage.

ExploringMycobacterium tuberculosis infection-induced alterations in gene expression in macrophage by microarray hybridization.

Tuberculosis remains a serious threat to public health. Its causative agentMycobacterium tuberculosis is an intracellular pathogen which survives and replicates within cells of the host immune system, primarily macrophages. Knowledge of the bacteria-macrophage interaction can help to develop novel measures to combat the disease. The global gene expression of macrophage following invasion by and growth ofM. tuberculosis was studied by cDNA microarray. Of the 12800 human genes analyzed, totally 473 (3.7%) macrophage genes were differentially expressed after being infected byM. tuberculosis, among which, only 25 (5.2%, corresponding to less than 0.2% of the 12800 genes) genes were up-regulated, while others (94.8%) were down-regulated against the control. Of the 473 genes, 376 genes are registered in the GenBank, and 97 are novel genes. Expression of 5 up-regulated genes has been induced by more than 3-fold. 25 genes were down-regulated by more than 3-fold. Syndecan binding protein has been down-regu- lated up to 12.5-fold. The data gave an insight into the early gene expression in macrophage ensuingM. tuberculosis infection and a basis for further study.

[Differential expression of human macrophage genes encoding cytokines and their regulatory elements after Mycobacterium tuberculosis infection].

To investigate whether the genes encoding cytokines and their regulatory elements participated in the immune response to Mycobacterium tuberculosis infection. Expression microarray was employed to compare the avirulent strain and clinically isolated strains infection induced macrophage cytokine differential expression. Results were cytokines IFN, TNF, TGF, IL and their regulatory elements are involved in the immune reaction. IL-19 was first reported to be involved in the anti-Mtb immunity. Relative expression level of theses factors before and after infection were assayed too. The data provides clues for further scrutinize the role of cytokines and related elements in the interaction between Mycobacterium tuberculosis and host macrophage.

[Human-centered ergonomical study and applications in manned spacecraft project of China].

High G and weightlessness are two important environment factors that are unavoidable during spaceflight. They will bring key effects on astronauts' posture and working efficiency. In this paper, on the basis of experience of China first manned spacecraft project in the past 10 years, the concept of space ergonomics and its role in the project were reviewed. Ergonomic research items and corresponding methods were systematically analyzed with astronauts' working state, and ergonomic evaluation types and approaches were discussed with some given cases being used in the project. Finally, some suggestions were proposed on space man-machine system development according to recent ergonomic trend in space ergonomics and the basis of experience of first manned spacecraft project.