Progress on lysosomal PPT1-mediated regulation of cellular homeostasis and pathogenesis.

Palmitoyl protein thioesterase 1(PPT1) is a lysosomal enzyme that catalyzes the protein depalmitoylation. It is considered to play a crucial role in regulating lysosomes, mitochondria and lipid metabolism. PPT1 has been reported to play an important role in the occurrence and progression of diseases, such as neurological diseases and cancers. However, the regulatory mechanisms remain unknown. In this review, we summarize the progress of PPT1 function and mechanisms in neurological disorders and cancers, which will provide as reference and guidance for exploring the regulatory mechanisms of PPT1 and developing new drugs for treating related diseases in the future.

Chromosome-level Dinobdella ferox genome provided a molecular model for its specific parasitism.

BACKGROUND: Dinobdella ferox is the most frequently reported leech species parasitizing the mammalian nasal cavity. However, the molecular mechanism of this special parasitic behavior has remained largely unknown. METHODS: PacBio long-read sequencing, next-generation sequencing (NGS), and Hi-C sequencing were employed in this study to generate a novel genome of D. ferox, which was annotated with strong certainty using bioinformatics methods. The phylogenetic and genomic alterations of D. ferox were then studied extensively alongside the genomes of other closely related species. The obligatory parasitism mechanism of D. ferox was investigated using RNA-seq and proteomics data. RESULTS: PacBio long-read sequencing and NGS yielded an assembly of 228 Mb and contig N50 of 2.16 Mb. Along Hi-C sequencing, 96% of the sequences were anchored to nine linkage groups and a high-quality chromosome-level genome was generated. The completed genome included 19,242 protein-coding genes. For elucidating the molecular mechanism of nasal parasitism, transcriptome data were acquired from the digestive tract and front/rear ends of D. ferox. Examining secretory proteins in D. ferox saliva helped to identify intimate connections between these proteins and membrane proteins in nasal epithelial cells. These interacting proteins played important roles in extracellular matrix (ECM)-receptor interaction, tight junction, focal adhesion, and adherens junction. The interaction between D. ferox and mammalian nasal epithelial cells included three major steps of pattern recognition, mucin connection and breakdown, and repair of ECM. The remodeling of ECM between epithelial cells of the nasal mucosa and epithelial cells of D. ferox may produce a stable adhesion environment for parasitism. CONCLUSIONS: Our study represents the first-ever attempt to propose a molecular model for specific parasitism. This molecular model may serve as a practical reference for parasitism models of other species and a theoretical foundation for a molecular process of parasitism.

The roles and mechanism of STIM1 in tumorigenesis and metastasis.

STIM1 (stromal interaction molecule 1) is one of the key components of the store operated Ca2+ entry channel (SOCE), which is located on the endoplasmic reticulum membrane and highly expressed in most kinds of tumors. STIM1 promotes tumorigenesis and metastasis by modulating the formation of invadopodia, promoting angiogenesis, mediating inflammatory response, altering the cytoskeleton and cell dynamics. However, the roles and mechanism of STIM1 in different tumors have not been fully elucidated. In this review, we summarize the latest progress and mechanisms of STIM1 in tumorigenesis and metastasis, thereby providing insights and references for the study on STIM1 in the field of cancer biology in the future.

Neofusicoccum cryptomeriae sp. nov. and N. parvum Cause Stem Basal Canker of Cryptomeria japonica in China.

Cryptomeria japonica D. Don is a coniferous tree species widely grown in southern China for its high ornamental value. Recently, during disease surveys in China, a symptom of dieback occurred on C. japonica in Nanjing, Jiangsu Province, China. A total of 130 trees were surveyed and more than 90% showed the same symptom. The crowns of affected trees were brown when viewing from a distance, and the bark showed no difference from the healthy ones. In this study, 157 isolates were isolated from the 3 affected plants of C. japonica, and based on the living culture on PDA, the fungal isolates were preliminarily divided into 6 groups. Thirteen representative isolates were selected for the pathogenicity test, and seven of them showed obvious pathogenicity on C. japonica, causing stem basal canker. These isolates were identified based on comparisons of the DNA sequences of the internal transcribed spacer regions (ITS), partial translation elongation factor 1-alpha (tef1), ß-tubulin (tub2), and DNA-directed RNA polymerase II subunit (rpb2) and combined with their morphological characteristics. Results showed that these seven isolates belong to two taxa in Neofusicoccum, including a species new to science. The new species, Neofusicoccum cryptomeriae, was hereby described and illustrated. The other species was N. parvum. Both species were pathogens of stem basal canker of Cryptomeria japonica.

The role and regulatory mechanism of FSCN1 in breast tumorigenesis and progression.

FSCN1, an actin-bundling protein, is highly expressed in almost all metastatic tumors and is associated with the poor prognosis. In breast cancer FSCN1 is highly expressed in basal-like and triple negative subgroups. There is significant progress in understanding the role of fascin in breast cancer. Studies on FSCN1 in recent years have revealed that FSCN1 not only promotes tumor migration, invasion, metastic colonization, cancer cell self-renewal and drug resistance, but also regulates glucose and lipid metabolism and mitochondrial remodeling in tumor cells. In this review, we focus on the structure and regulatory mechanism of FSCN1 in breast tumorigenesis and metastasis, and discuss the clinical value of FSCN1 with the aim to provide a direction for further research in this field.

Progress on the role and mechanism of MT1-MMP in tumor metastasis.

The matrix metallopeptidase family (matrix metallopeptidase, MMPs) is a class of zinc-dependent endopeptidases that can degrade most extracellular matrices. MT1-MMP (membrane type 1 metalloprotease) is an important metallopeptidase, which is located on plasma membrane and highly expressed in most tumors. MT1-MMP promotes cancer metastasis through affecting the extracellular matrix remodeling, angiogenesis, lipid metabolism, and inflammation. However, the mechanisms of MT1-MMP in different tumors have not been fully elucidated. In this review, we summarize the latest progress and the metastasis-promoting regulatory mechanisms of MT1-MMP in different tumors, which will provide references for its in-depth research and application in the field of cancer biology.

First Report of Top Blight of Cunninghamia lanceolata Caused by Diaporthe unshiuensis and Diaporthe hongkongensis in China.

Cunninghamia lanceolata (Lamb.) Hook. is an important conifer species widely planted in southern China. A top blight, with an incidence of 20% (40/200 seedlings), occurred on 1-year-old seedlings of C. lanceolata in a nursery, Luzhai, Guangxi, China in August 2021. The disease mainly occurred on shoot tips. The infected needles and shoots appeared brown to brownish red. White conidial tendrils oozed from pycnidia under wet-weather conditions. Lesion margins from fresh samples were cut into small pieces (n=100), which were sterilized according to Mao et al., and placed on potato dextrose agar (PDA) at 25°C. Three isolates (GXJ2, GXJ4, and GXJ6) were obtained and deposited in The China Forestry Culture Collection Center (CFCC 55717, CFCC 55716, and CFCC 55722). The colony of GXJ2 on PDA was white, with sparse aerial mycelia, and became grey with time. The α conidia were fusiform, hyaline, and aseptate, 6.7±0.6 µm × 2.6±0.2 µm (n=30). The ß conidia were filiform, hyaline, and curved, 30.4±2.1 µm × 1.4±0.1 µm (n=30). Colonies of GXJ4 and GXJ6 were white, with moderate aerial mycelia, which collapsed at the center, and the collapsed parts were iron-gray. The α conidia were 7.8±0.8 µm × 2.5±0.2 µm (n=30). The ß conidia were absent. Morphological characters of 3 isolates matched those of Diaporthe spp.. The partial sequences of ITS, EF1-α, CAL, ß-tub, and HIS genes were amplified with primers ITS1/ITS4, EF1-728F/EF1-986R and CAL228F/CAL737R, ßt2a/ßt2b and CYLH3F/H3-1b according to Gomes et al. 2013, respectively. The sequences for the five genes of each of 3 isolates were deposited in GenBank (Accession Nos. see Supplementary Table 1). BLAST results showed that the ITS, EF1-α, ß-tub, HIS, and CAL sequences of GXJ2 were highly similar (>99%) with sequences of Diaporthe unshiuensis, while sequences of GXJ4 and GXJ6 were highly similar (>99%) to those of D. hongkongensis (Supplementary Table 1). Phylogenetic analyses using concatenated sequences placed GXJ2 in the clade of D. unshiuensis, while GXJ4 and GXJ6 in the clade of D. hongkongensis. Based on the phylogeny and morphology, GXJ2 was identified as D. unshiuensis, GXJ4 and GXJ6 as D. hongkongensis. Pathogenicity tests were performed on nine 1-year-old seedlings of C. lanceolata, and 10 needles at shoot tip per seedling were slightly wounded and inoculated with 5-mm mycelial plugs from one of 3 isolates. Three control seedlings were treated with PDA plugs. Each plant was covered with a plastic bag after inoculation and kept in an air-conditioned nursery at 25°C/16°C (day/night). The symptoms appeared 5-8 days after inoculation and were similar to those observed in the nursery. D. unshiuensis and D. hongkongensis were re-isolated from the inoculated seedlings and were confirmed based on morphology and ITS sequences. The controls were symptomless, and no fungus was isolated from them. D. unshiuensis was first reported as an endophyte on the fruit of Citrus unshiu, and caused peach constriction canker, shoot blight of kiwifruit. D. hongkongensis was first described from fruit of Dichroa febrifuga and caused shoot canker of pear, shoot blight and leaf spot of kiwifruit, and fruit rot of peach. This is the first report of D. unshiuensis and D. hongkongensis causing the top blight of C. lanceolata. This study provides a basis for controlling this newly emerging disease in the nursery.

Lymph node ratio-based the ypTNrM staging system for gastric cancer after neoadjuvant therapy: a large population-based study.

PURPOSES: The lymph node ratio (LNR) has been considered a better prognostic factor than traditional N staging in patients with gastric cancer (GC), but its accuracy is unclear for those who receive neoadjuvant therapy (NAT). We aimed to compare the node ratio (Nr) staging with the ypN staging and to thereby develop a modified staging system incorporating Nr staging. METHODS: A total of 1791 patients who underwent gastrectomy after NAT in the Surveillance, Epidemiology, and End Results database were retrospectively analyzed. ypTNrM staging was established based on the overall survival (OS). RESULTS: The Nr staging was generated using 0.2 and 0.5 as the cutoff values of LNR and represented patients with more homogeneous OS compared with ypN staging. The 5-year OS rates for ypTNrM stages IA, IB, II, IIIA, and IIIB were 70.2%, 54.2%, 36.0%, 21.2%, and 6.6%, respectively, compared with 58.8%, 39.1%, and 21.6% for ypTNM stages I, II, and III, respectively. Compared with the ypTNM staging system, the ypTNrM staging system had a lower misclassification rate (3.0% vs. 50.9%) and better prognostic predictive power (C-index: 0.645 vs. 0.589, P < 0.001). CONCLUSIONS: The ypTNrM staging system incorporating Nr staging may provide a more accurate assessment in the clinical decision-making process for GC after NAT.

Early and late recurrences in lymph node-negative gastric cancer: a retrospective cohort study.

BACKGROUND: Predictors of recurrence in patients with lymph node-negative gastric cancer (GC) who have undergone curative resection have been widely investigated, but not the effects of predictors on timing of recurrence. OBJECTIVE: Determine the factors associated with early and late recurrence in patients with node-negative GC. DESIGN: Retrospective cohort. SETTING: Academic tertiary care center. PATIENTS AND METHODS: The study included patients with node-negative GC after curative resection between 2008 and 2018 at two institutions. Early and late recurrences were determined using a minimum P value approach to evaluate the optimal cutoff for recurrence-free survival (RFS). A competing risk model and landmark analysis were used to analyze factors associated with early and late recurrences. MAIN OUTCOME MEASURES: Recurrence-free survival and factors associated with survival. SAMPLE SIZE: 606. RESULTS: After a median follow-up of 70 months, 50 (8.3%) patients experienced recurrent disease. The optimal length of RFS for distinguishing between early (n=26) and late recurrence (n=24) was 24 months (P=.0013). The median RFS in the early and late recurrence groups was 11 and 32 months, respectively. Diffuse tumors (hazard ratio 3.358, P=.014), advanced T stage (HR 8.804, P=.003), perineural invasion (HR 10.955, P<.001), and anemia (HR 2.351, P=.018) were independent predictors of early recurrence. Mixed tumor location (HR 5.586, P=.002), advanced T stage (HR 5.066, P<.001), lymphovascular invasion (HR 5.902, P<.001), and elevated CA19-9 levels (HR 5.227, P<.001) were independent predictors of late recurrence. Similar results were obtained in the landmark analysis. CONCLUSIONS: Individualized therapeutic and follow-up strategies should be considered in future studies because of distinct patterns in predictors of early and late recurrence. LIMITATIONS: Retrospective design, small sample size. CONFLICT OF INTEREST: None.

[Distribution Characteristics of Viruses Microorganisms in a Water Supply System with Combined Ultraviolet Chloramine Disinfection].

To study the effect of combined ultraviolet (UV) chloramine disinfection on viruses in a drinking water supply system, a full-scale experiment was conducted to analyze the distribution, variability, community structure, and hosts of viruses using metagenomics. The results showed that the combined UV chloramine process reduced the number of virus species (6.13%) and gene abundance (51.97%) but did not completely remove the viruses from the water. The United States Environmental Protection Agency (USEPA) report that virus removal efficiencies from water can reach 99%-99.99% based on culturing methods. However, in this study, metagenomic analysis indicated a total virus removal rate of only 93.46%. Therefore, the detection of viruses in water using culturing method cannot reliably detect viruses in drinking water. Caudovirales are the most abundant type of virus in water supply systems and are sensitive to chloramine disinfection. Lentivirus, as a virus that can infect humans and vertebrates, has strong resistance to UV and chloramine disinfection. The main virus hosts in the studied water supply system were bacteria (61.50%). The viruses in the raw water were mainly parasitic in Synechococcus. The dominant virus host was Pseudomonas in both the effluent water and pipe network water. The gene abundance of the Pseudomonas aeruginosa host in the pipe network increased by 342.62%, which requires further attention as a virus risk in pipe network systems. Overall, combined UV chloramine disinfection was more effective at the removal of virus hosts than single UV disinfection (51.97% compared to 0.79%).

First Report of Leaf Blotch of Salix babylonica Caused by Botryosphaeria dothidea in China.

Salix babylonica L. (weeping willow) is an important ornamental tree commonly planted in China. Since 2018, a new disease with a high incidence has been observed on S. babylonica at the campus of Nanjing Forestry University (NFU), Nanjing, Jiangsu, China. The symptoms began as small dark brown lesions formed along the leaf margins and tips; and later became gray to brown in the center with dark brown borders. Small samples (3 to 4 mm2) from the lesion margins were surface-sterilized with 75% ethanol for 30 s and 1% NaClO for 90 s. Subsequently samples were, rinsed with sterile H2O, plated on potato dextrose agar (PDA) and incubated at 25°C. The same fungus was isolated in 95% of the samples. Pure cultures were obtained by monosporic isolation. A representative isolate, NFS1 was used for morphological and molecular characterization and deposited in China's Forestry Culture Collection Center (cfcc 54212). On PDA, colonies were initially white and gradually became grayish-green to dark gray from the center to the edge. After 1 week, colonies turned dark, and after 3 weeks black pycnidia developed on the surface of media. Conidia were one-celled, hyaline, smooth, and fusoid to ellipsoid. Conidia measurements were 23.0 ± 1.9 × 5.8 ± 0.7 µm (n = 50). The morphology matched the description of Botryosphaeria dothidea (Slippers et al. 2004). For an accurate identification, genomic DNA of NSF1 was extracted to amplify the internal transcribed spacer (ITS) region, the transcription eongation factor (tefa-1), beta-tubulin (ß-tub), the large subunit (LSU), and small subunit (SSU) genes with the specific primers ITS1/ITS4 (White et al. 1990), EF1-728F/EF1-986R (Carbone and Kohn, 1999), ßt2a/ßt2b (Glass and Donaldson, 1995), LR0R/LR05 (Schoch et al. 2009), and NS1/NS4 (White et al. 1990), respectively. The sequences were deposited in GenBank (Accession Nos. MN826233 for ITS, MN855215 for tefa-1, MN855216 for ß-tub, MN886965 for LSU, and MN886966 for SSU). A BLAST search of GenBank showed that the ITS, tefa-1, ß-tub, LSU and SSU sequences of NSF1 were similar to those of B. dothidea KY788304 (Identity = 527/532; 99%), MG459974 (Identity = 247/247; 100%), MH724212 (Identity = 404/404; 100%), DQ377850 (Identity = 865/867; 99%), and KX091154 (Identity = 1,043/1,045; 99%), respectively. A maximum likelihood and Bayesian posterior probability-based phylogenetic analyses using IQ-tree v. 1.6.8 and Mr. Bayes v. 3.2.6 with the concatenated sequences (ITS, tefa-1, ß-tub, LSU, and SSU) placed NFS1 in the clade of B. dothidea. Based on the multi-gene phylogeny and morphology, NFS1 isolate was identified as B. dothidea. To fulfill Koch's postulates, 20 detached and 20 attached healthy 10-week-old leaves from three 30-year-old S. babylonica plants at the campus of NFU were inoculated with 5-mm mycelial plugs of isolate NFS1 of 3-day-old cultures grown on PDA. Control leaves were treated with agar plugs. The detached inoculated leaves were placed in Petri dishes on a piece of wet filter paper and incubated at 25°C. The attached leaves were enclosed in a plastic bag along with the branches with a wet cotton ball inside. Sterile H2O was sprayed into the plastic bags twice daily to keep moisture conditions and incubated for 5 days. The experiment was repeated two times. Within 5 days, all the inoculated points showed lesions similar to those obsrved in the field, whereas controls were asymptomatic. The same fungus was re-isolated from these lesions with a frequency of 100%. B. dothidea has been reported to infect a broad range of hosts, including S. babylonica in the USA (Grand 1985). This is the first report of B. dothidea on S. babylonica in China. This finding provides crucial information on this high risk disease to willow and basis for identifying management strategies.

Prognostic value of lymphocyte-to-C-reactive protein ratio in patients with gastric cancer after surgery: a multicentre study.

OBJECTIVE: The immune inflammation-based score is recognized as a prognostic marker for cancer. However, the most accurate prognostic marker for patients with gastric cancer remains undetermined. We aimed to evaluate the predictive value of the lymphocyte-to-C-reactive protein ratio for outcomes in gastric cancer patients after radical gastrectomy. METHODS: A total of 607 gastric cancer patients treated at three Chinese institutions were included. Receiver operating characteristic curves were generated, and the areas under the curve were calculated to compare the predictive value among the inflammation-based score, lymphocyte-to-C-reactive protein ratio, C-reactive protein/albumin and neutrophil-lymphocyte, platelet-lymphocyte and lymphocyte-monocyte ratios. Cox regression was performed to determine the prognostic factors for overall survival. RESULTS: The median follow-up time was 63 months (range: 1-84 months). The optimal cut-off value for lymphocyte-to-C-reactive protein ratio was 0.63. The patients were divided into the LCR <0.63 (LLCR, n = 294) group and the LCR ≥0.63 (HLCR, n = 313) group. LLCR was significantly correlated with poor clinical characteristics. Compared with inflammation-based score, lymphocyte-to-C-reactive protein ratio had the highest areas under the curve (0.695). Patients with LLCR experienced more post-operative complications than the HLCR group (20.4 vs. 12.1%, P = 0.006). Multivariate analysis showed that a higher lymphocyte-to-C-reactive protein ratio (HR: 0.545, 95%CI: 0.372-0.799, P = 0.002) was associated with better overall survival. The HLCR group had higher 5-year overall survival rate than the LLCR group (80.5 vs. 54.9%, P < 0.001). CONCLUSIONS: Preoperative lymphocyte-to-C-reactive protein ratio levels can effectively predict the short-term and oncological efficacy of gastric cancer patients after radical gastrectomy with a predictive value significantly better than other inflammation-based score.

[Effect of Qingyi Chengqi Decoction on severe acute pancreatitis patients: a clinical study].

OBJECTIVE: To observe the change of intra-abdominal pressure (IAP) in severe acute pancreatitis (SAP) patients, and to study the effect of Qingyi Chengqi Decoction (QCD) on it. METHODS: Eighty-six SAP patients from Department of General Surgery and Department of Digestive Diseases, Qingyang People's Hospital, Gansu Province, who were in line with diagnosis standard of SAP, were assigned to the treatment group (44 cases) and the control group (42 cases) from March 2012 to May 2013. All patients received routine Western medicine. Those in the treatment group took QCD additionally. Main clinical symptoms and APACHE II were observed. The serum levels of amylase (AMY), C-reactive protein (CRP), and IAP were examined. The incidence of secondary infection rate (SIR), drainage rate (percutaneous catheter drainage and operation), mortality, and mean days in ward were also recorded. RESULTS: Main clinical symptoms were significantly improved in the treatment group. APACHE II score, serum levels of AMY, CRP, and IAP obviously decreased in the treatment group. The incidence of SIR, drainage rate, and the mortality were also significantly lower in the treatment group than in the control group. The mean days in ward were also markedly shortened (P < 0.01). CONCLUSION: QCD could relieve inflammatory response, lower IAP, SIR, and mortality, increase the curative rate and improve the prognosis of SAP.

[The spatial distribution and dynamics of human rabies cases at the county level in Henan province].

OBJECTIVE: To study the spatial distribution and dynamics of human rabies cases at the county level, in Henan province to provide scientific evidence for the development of control program on rabies. METHODS: Data of human rabies cases at the county level from 2004 to 2010 in Henan province were analyzed by Poisson distribution and negative binomial distribution. Data calculation was conducted manually. RESULTS: According to the level of α = 0.05 being set, there were three different results appeared:the first was fitted negative binomial distribution in 2004, 2005, 2007 and 2009; the second was prioritized negative binomial distribution, but the poisson distribution could not be excluded in 2008 and 2010;the last one was fitted neither negative binomial distribution nor poisson distribution in 2006. By the clustering parameter k, the clustering degree at county level decreased from 2004 to 2008, then ascending in 2009 but descending again in 2010. The degree of clustering showed a positive correlation with the county mean cases in the prevalent counties (r = 0.807, P = 0.028). CONCLUSION: As a whole, the distribution of human rabies at county level in Henan from 2004 to 2010 showed negative binomial distribution and presented the spatial clustering. However, the degree of clustering decreased in recent years and showed that the infection resource was possibly scattered more evenly at the county level.

[A study on the bonding properties of four resin cements].

OBJECTIVE: To evaluate the dentin and enamel bonding strength and resin-dentin interfaces of four resin cements. METHODS: Twenty-four sound freshly extracted molars were sectioned with low-speed saw under running water. Two mesial-distal enamel disc and two buccal-lingual dentin discs were sectioned from each molar. Four resin cements (A group: Panavia(TM) F; B group: RelyX(TM) ARC; C group: RelyX(TM) Unicem; D group: Clearfil(TM) SA Cement) were applied to the surface of these enamel and dentin discs according to manufacturers' guidance. The bonded specimen were prepared for shear bond strength test and sectioned occluso-gingivally into two slabs for scanning electron microscopy (SEM) observation. RESULTS: The bonding strength between resin and enamel in B group [(29.38 ± 6.28) MPa] was higher than that in D group [(27.25 ± 7.03) MPa], and both of them were significantly higher than those in A [(22.92 ± 7.13) MPa] and C group [(10.92 ± 3.41) MPa] (P < 0.05). The highest dentin bonding strength was shown in B group [(27.28 ± 6.79) MPa], followed by A [(14.23 ± 6.39) MPa], D [(10.09 ± 3.26) MPa] and C group [(6.43 ± 1.60) MPa, P < 0.05]. CONCLUSIONS: The four resin cements have different enamel or dentin bonding properties.

[Discussion on five methods used for the determination of temporal clustering on infectious diseases].

To demonstrate and evaluate five different methods in the determination of temporal clustering on infectious diseases. The incidence rates of bacillary dysentery in Jinshui district, Zhengzhou city, Henan province from 2008 to 2010 were analyzed by 5 different methods-Cluster Analysis, Runs Test, Negative Binomial Distribution, Circular Distribution and Concentration Ratio. Through Cluster Analysis, data showed that the epidemic period was from May to Sept. with August as the peak. Runs Test confirmed a cluster of month-incidence in 2008 and 2009 (P < 0.05) and a random distribution in 2010. The Concentration Ratio showed a weakened seasonal incidence cluster to a certain extent by M from 2008 to 2010. The Circular Distribution demonstrated an inclining cluster of time (P < 0.01) and it was on July 11(th) and 29(th), as well on August 24(th) in 2008, 2009 and 2010. In terms of day-incidence, the Negative Binomial Distribution presented a cluster in 2008 and 2010, but with no significant difference in 2009. The five above said methods could flexibly be used in determining the temporal clustering of infectious disease at different occasions.

[Effects of Swan-like Shape Memory Connector on stress shielding rate and callus development during experimental fracture healing process].

OBJECTIVE: To investigate the stress shielding rate, ultrastructural and biomechanical property of the healing bone fixed by Swan-like Shape Memory Connector (SMC) during experimental fracture healing in rabbits. METHODS: Unilateral osteotomy of left humeral diaphysis was performed in 140 adult New Zealand rabbits. The humeral fracture was fixed with SMC in study group and 4-hole dynamic compression plate (DCP) in control group. The animals were sacrificed at the 2nd, 4th, 8th, 12th, and 16th weeks postoperatively. The humeral shafts were harvested for three-point bending tests and stress shielding rate examination. Samples from the fracture gaps were observed with scanning electron microscope. RESULTS: Within an observation period of 12 weeks after operation, the stress shielding rates were significantly lower in study group than those in control group, and the bending strength and the bending rigidity were statistically higher. It was also found that collagen fibers in callus was arranged more regulate and early mineral deposition in study group. CONCLUSION: These results suggest that SMC contributes to the proliferation and differentiation of osteoblasts, promoting the formation and calcification of bone matrix and enhancing biomechanical property of the healing bone, which might be closely correlated with a less stress shielding effect produced by SMC.

[Analyses on the isolation and characterization of canine rabies virus isolates in Henan].

OBJECTIVE: To analyze the genetic characteristics of two rabies virus isolates from Henan province and to compare their relations hip with known rabies virus isolates and vaccine strains. METHODS: Rabies viral antigens were detected in 100 canine brains by immunofluorescence assay method. Rabies virus was isolated through inoculating the suspensions of positive brains into suckling mice. N gene and G were amplified by RT-PCR and sequenced. Phylogenetic trees were constructed for the analysis on genetic characteristics of rabies virus. RESULTS: Two rabies virus strains were isolated (Henan Hb1 and Henan Sq1). Data from sequential comparison revealed that the nucleotide and amino acid identities of N and G gene between the two isolates were 99.3% and 98.9%, and 98.7% and 98.4% respectively. The two isolates were more closely related to CTN, with the homogeny of N gene and G gene as 89.1% and 85.6%-85.7% at the nucleotide level, but 97.6%-98.0% and 92.3% at the amino acid level respectively, than to other vaccine strains. When comparing with other known viruses including Chinese isolates, the two stains shared closer identity with the isolates from Indonesia, and the rates of homogeny of N and G gene were 92.1%-93.2% and 91.9%-92.1% at the nucleotide level, 97.5%-98.6% and 96.0%-96.2% at the amino acid level, respectively. Data from the deduced amino acid sequences revealed that some amino acid residues including the residues in the N and G antigenic sites were substituted in the two isolates. Furthermore, phylogenetic analysis showed that the two isolates were also more closely related to the strains from Indonesia and vaccine strain CTN than to any other known street viruses and vaccine strains. CONCLUSION: Both Henan Hbl and Henan Sql belonged to genotype 1. However, the N and G gene diverged from known street viruses and vaccine strains at either nucleotide level or amino acid level.

[Genetics subtypes and distribution of Seoul virus in Henan].

OBJECTIVE: To investigate the sub-genotypes and distribution ot Seoul virus in Henan. METHODS: Rodents were collected in the major epidemic areas and rats lungs were studied by indirect immunofluorescence assay. Partial M and S segments were amplified with nested reverse transcription-polymerase chain reaction using Hantavirus genotype-specific primers, sequenced, analyzed and compared with other known sequences. RESULTS: The Hantavirus carried by Rattus norvegicus, Rattus flavipectus and Mus musculus were all belonged to Seoul virus in the main epidemic areas of Henan. We constructed two phylogenetic tree based on the partial M and S segment sequences while phylogenetic analysis distinguished three genetic subtypes (S1, S2 and S3). S1 and S3 were found main subtypes in Henan. CONCLUSION: The results indicated that the genetic subtypes of Hantavirus were complicated and widely distributed in Henan.