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Heng Li

Publications and source records attributed to Heng Li.

At least 37 records · Page 2Linked to original sources
PubMed2006

TreeFam: a curated database of phylogenetic trees of animal gene families.

TreeFam is a database of phylogenetic trees of gene families found in animals. It aims to develop a curated resource that presents the accurate evolutionary history of all animal gene families, as well as reliable ortholog and paralog assignments. Curated families are being added progressively, based on seed alignments and trees in a similar fashion to Pfam. Release 1.1 of TreeFam contains curated trees for 690 families and automatically generated trees for another 11 646 families. These represent over 128 000 genes from nine fully sequenced animal genomes and over 45 000 other animal proteins from UniProt; approximately 40-85% of proteins encoded in the fully sequenced animal genomes are included in TreeFam. TreeFam is freely available at http://www.treefam.org and http://treefam.genomics.org.cn.

Animals↗
PubMed2006

Feasibility of interstitial Doppler optical coherence tomography for in vivo detection of microvascular changes during photodynamic therapy.

INTRODUCTION: Doppler optical coherence tomography (DOCT) is an emerging imaging modality that provides subsurface microstructural and microvascular tissue images with near histological resolution and sub-mm/second velocity sensitivity. A key drawback of OCT for some applications is its shallow (1-3 mm) penetration depth. This fundamentally limits DOCT imaging to transparent, near-surface, intravascular, or intracavitary anatomical sites. Consequently, interstitial Doppler OCT (IS-DOCT) was developed for minimally-invasive in vivo imaging of microvasculature and microstructure at greater depths, providing access to deep-seated solid organs. Using Dunning prostate cancer in a rat xenograft model, this study evaluated the feasibility of IS-DOCT monitoring of microvascular changes deep within a tumor caused by photodynamic therapy (PDT). MATERIALS AND METHODS: The DOCT interstitial probe was constructed using a 22 G (diameter approximately 0.7 mm) needle, with an echogenic surface finish for enhanced ultrasound visualization. The lens of the probe consisted of a gradient-index fiber, fusion spliced to an angle-polished coreless tip to allow side-view scanning. The lens was then fusion spliced to a single-mode optical fiber that was attached to the linear scanner via catheters and driven along the longitudinal axis of the needle to produce a 2D subsurface DOCT image. The resultant IS-DOCT system was used to monitor microvascular changes deep within the tumor mass in response to PDT in the rat xenograft model of Dunning prostate cancer. Surface PDT was delivered at 635 nm with 40 mW of power, for a total light dose of 76 J/cm(2), using 12.5 mg/kg of Photofrin as the photosensitizer dose. RESULTS: IS-DOCT demonstrated its ability to detect microvasculature in vivo and record PDT-induced changes. A reduction of detected vascular cross sectional area during treatment and partial recovery post-treatment were observed. CONCLUSIONS: IS-DOCT is a potentially effective tool for real-time visualization and monitoring of the progress of PDT treatments. This capability may play an important role in elucidating the mechanisms of PDT in tumors, pre-treatment planning, feedback control for treatment optimization, determining treatment endpoints and post-treatment assessments.

Animals↗
PubMed2006

Intrathecal administration of Cav3.2 and Cav3.3 antisense oligonucleotide reverses tactile allodynia and thermal hyperalgesia in rats following chronic compression of dorsal root of ganglion.

AIM: The present study aimed to elucidate the role of T-subtype calcium channels (Cav3.1, Cav3.2, and Cav3.3) in the pathogenesis of neuropathic pain at spinal level. METHODS: The chronic compression of the dorsal root ganglion (CCD) rat model was adopted. The antisense oligonucleotide of Cav3.1, Cav3.2, and Cav3.3 or normal saline (NS) were intrathecally administered twice per day from the first day to the fourth day after operation. Paw mechanical withdrawal threshold and paw thermal withdrawal latency were measured to evaluate the tactile allodynia and thermal hyperalgesia, respectively. RESULTS: CCD rats developed reliable tactile allodynia and thermal hyperalgesia after operation. Intrathecal administration of antisense oligonucleotide of Cav3.2 and Cav3.3 significantly relieved tactile allodynia and thermal hyperalgesia in CCD rats, but not Cav3.1. CONCLUSION: Cav3.2 and Cav3.3 subtype calcium channels in the spinal cord may play an important role in the pathogenesis of neuropathic pain, which may contribute to the management of the neuropathic pain.

Animals↗
PubMed2006

[Treatment of fractures of proximal radius with Ni-Ti shape memory alloy embracing].

OBJECTIVE: To find out an ideal method of internal fixation for the treatment of fractures of proximal radius. METHODS: From August 2001 to April 2004, 24 patients suffering from fractures of proximal radius were treated with Ni-Ti shape memory alloy embracing fixator. Of 24 patients, there were 19 males and 5 females, aging from 16 to 48 years; there were 9 cases of wrestling injury, 5 cases of crush injury, 4 cases of traffic accident injury, 3 cases of direct violence impact injury and 3 cases of high falling injury. All patients were given operation according to fix method of the shape memory alloy embracing fixator. All cases were regularly followed up to observe the fracture healing and functional recovery. RESULTS: All cases were followed up postoperatively from 4 months to 21 months with an average of 10 months. No complication occurred during operation and after operation. Healing by first intention was achieved. X-ray showed that all cases achieved clinical union 8-12 weeks after operation. According to Anderson's criteria and the results were excellent in 18 cases, good in 5 cases, and fair in 1 case. The excellent and good rate was 95.83%. CONCLUSION: The internal fixation with shape memory alloy embracing fixator has as follows advantages: less trauma, esay-to-do, stable fixation, better tissue compatibility and less complication in treating fractures of proximal radius. This method can enhance the fracture healing and functional recovery. So it is a better method to treat fractures of proximal radius.

Adolescent↗
PubMed2006

[Effects of preoperative acute hypervolemic hemodilution on hypercoagulability of patients with colon cancer].

BACKGROUND & OBJECTIVE: Cancer patients have an increased risk of thrombosis after operation because of a hypercoagulable status. Therefore, anticoagulant treatment is necessary for patients with hypercoagulability during perioperative period. This study was to investigate the effect of acute hypervolemic hemodilution (AHHD) with 6% hydroxyethyl starch (HES), or 4% succinylated gelatin (GEL), or lactated Ringer's (RL) solution before operation on the hypercoagulable status and the occurrence of deep venous thrombosis (DVT) of patients with colon cancer. METHODS: Sixty colon cancer patients with hypercoagulable status underwent operation were randomized into HES, GEL, and RL groups; each group contained 20 patients. The patients were infused with HES, GEL, or RL solution respectively at a dose of 15 ml/kg within 30 min before operation. Preoperative coagulation function was assessed by thrombelastography (TEG). DVT was diagnosed by the color Doppler ultrasonic system. RESULTS: Acute hypervolemic hemodilution with HES solution led to a significant decrease of coagulation index (CI) at 30 min and 2 h after starting operation and 1 h after operation as compared with the prehemodilution value (P<0.01). At 1 h after operation, CI was significantly lower in HES group than in GEL group (P<0.05). At 30 min and 2 h after starting operation and 1 h after operation, CI was significantly lower in HES group than in RL group (P<0.05). Hemodilution with GEL solution lessened CI at 30 min and 2 h after starting operation significantly as compared with the prehemodilution value (P<0.01). At 30 min and 2 h after starting operation, CI was significantly lower in GEL group than in RL group (P<0.05). After operation, DVT in occurred 2 (10%) patients in HES group, 3 (15%) in GEL group, and 10 (50%) in RL group (P<0.05). CONCLUSION: Acute hypervolemic hemodilution with HES solution and GEL solution can alleviate the hypercoagulability of colon cancer patients during perioperative period and decrease the occurrence of DVT.

Adult↗
PubMed2006

[Role of MAPK signal transduction pathway phosphorylation induced by granulocyte-macrophage-colony stimulating factor in the proliferation of hormone-independent prostate cancer].

OBJECTIVE: To investigate the phosphorylation intensity of MAPK pathway molecular Erk1/2 and the proliferation of prostate cancer cell line PC-3M. METHODS: Flow cytometry and RT-PCR were employed to study the ratio of different cell cycles and phases, respectively, before and after GM-CSF stimulation. Erk1/2 phosphorylation intensity was examined by Western blot simultaneously. RESULTS: The rate of PC-3M cells at S and G2/M stages and the expression intensity of Ki-67 increased after GM-CSF incubation in a dose-dependent manner. The phosphorylation intensity of Erk1/2 increased remarkably after stimulation with GM-CSF. CONCLUSION: The intensification of Erk1/2 phosphorylation is one important molecular mechanism of the proliferation of hormone-independent prostate cancer.

Cell Line, Tumor↗
PubMed2005

Convenient new chemical actinometer based on aqueous acetone, 2-propanol, and carbon tetrachloride.

A convenient new chemical actinometer was developed to measure the spectral output of laboratory ultraviolet (UV) light sources over the wavelength range of 260-330 nm. It can also be used to measure solar UV irradiance (< or =325 nm). The actinometer is based on the photoreduction of aqueous carbon tetrachloride (CT) to chloroform (CF) in the presence of acetone (the chromophore) and 2-propanol (the reductant). In all cases, CT disappearance (and CF formation) followed zero-order kinetics over 95% of the reaction. The slope of the linear decay curve forms the basis of the new actinometer, which was calibrated using ferrioxalate actinometry. Quantum yields were measured at 10 nm intervals and were found to be uniform throughout the range of 260-300 nm. As expected, quantum yields gradually decreased to zero asthe wavelength was increased from 300 to 340 nm. The high quantum yields (approximately 150), low sensitivityto room light, and the straightforward determination of [CT] and [CF] by gas chromatography offer significant advantages over some other chemical actinometers, which might require the preparation and purification of light-sensitive compounds in a darkened environment and long exposure times.

2-Propanol↗
PubMed2005

The Genomes of Oryza sativa: a history of duplications.

We report improved whole-genome shotgun sequences for the genomes of indica and japonica rice, both with multimegabase contiguity, or almost 1,000-fold improvement over the drafts of 2002. Tested against a nonredundant collection of 19,079 full-length cDNAs, 97.7% of the genes are aligned, without fragmentation, to the mapped super-scaffolds of one or the other genome. We introduce a gene identification procedure for plants that does not rely on similarity to known genes to remove erroneous predictions resulting from transposable elements. Using the available EST data to adjust for residual errors in the predictions, the estimated gene count is at least 38,000-40,000. Only 2%-3% of the genes are unique to any one subspecies, comparable to the amount of sequence that might still be missing. Despite this lack of variation in gene content, there is enormous variation in the intergenic regions. At least a quarter of the two sequences could not be aligned, and where they could be aligned, single nucleotide polymorphism (SNP) rates varied from as little as 3.0 SNP/kb in the coding regions to 27.6 SNP/kb in the transposable elements. A more inclusive new approach for analyzing duplication history is introduced here. It reveals an ancient whole-genome duplication, a recent segmental duplication on Chromosomes 11 and 12, and massive ongoing individual gene duplications. We find 18 distinct pairs of duplicated segments that cover 65.7% of the genome; 17 of these pairs date back to a common time before the divergence of the grasses. More important, ongoing individual gene duplications provide a never-ending source of raw material for gene genesis and are major contributors to the differences between members of the grass family.

Base Sequence↗
PubMed2005

Tumour induction in rats following exposure to short-term high dose aristolochic acid I.

The purpose of this study was to assess the carcinogenic activity of aristolochic acid I (AAI) in short-term high doses. Forty-four female Sprague-Dawley rats were randomly assigned to two groups. A dose of 50 mg/kg/day AAI was administrated to rats in the experimental group by gavage consecutively for 3 days, while the control group received only distilled water, after which renal function and pathological changes were assessed. At day 8 post-treatment AAI had induced elevations of both plasma urea and creatinine, coupled with increased urine production, urinary proteins, glucose and N-acetyl-beta-glucosaminidase. At 1, 3 and 6 months post-treatment renal function and urinary parameters for the experimental group approached baseline values. However, tumours and preneoplastic proliferation were both observed at 6 months for the experimental group. The rate of occurrence of preneoplastic proliferation in the kidneys was 100% (14/14); the rate of occurrence of renal tumours was 28.6% (4/14), which included three mesenchymal tumours and one case of renal oncocytoma; the rate of occurrence of extrarenal tumours was 7.1% (1/14), which was a case of mammary duct carcinoma. Renal preneoplastic proliferation and renal tumours, as well as extrarenal tumours, were not observed in control rats during the 6 months. These results differ from previous reports in that tumours originating from both epithelial and mesenchymal tissues were found, which may be attributed to the duration of treatment and the dosage of the drug. These data indicate that AAI administered in an acute manner at high doses does in fact have carcinogenic properties.

Adenoma, Oxyphilic↗
PubMed2005

[Research advance of dynamic hip screw internal fixation in treatment of intertrochanteric fractures].

OBJECTIVE: To investigate the development of dynamic hip screw (DHS) internal fixation in the treatment of intertrochanteric femur fractures. METHODS: The latest relevant articles were reviewed extensively, including biomechanics and clinical application research. RESULTS: DHS is the effective selection for the treatment of intertrochanteric femur fractures, especially by the innovation of DHS structure, operative manipulation. CONCLUSION: Treatment of intertrochanteric femur fractures with DHS is still a gold level, but strict selection of patients, proficiency operation and invasive manipulation are the most essential principles.

Biomechanical Phenomena↗
PubMed2005

[Conception of Ashi points].

In the light of obscure conception of Ashi points in the circle of acupuncture and moxibustion at present, this article tries to clarify the origin and definition of Ashi points by textual research of literatures. It is put forward that Ashi points are not the same with "tender spot" and "Buding point, Tianying point", but are some special responding points, including regular points and extra points, when the organism is ill. When these points are pressed the organism will be comfortable or painful. And the definition, location and clinical location method of Ashi points are proposed.

Acupuncture↗
PubMed2004

A draft sequence for the genome of the domesticated silkworm (Bombyx mori).

We report a draft sequence for the genome of the domesticated silkworm (Bombyx mori), covering 90.9% of all known silkworm genes. Our estimated gene count is 18,510, which exceeds the 13,379 genes reported for Drosophila melanogaster. Comparative analyses to fruitfly, mosquito, spider, and butterfly reveal both similarities and differences in gene content.

Algorithms↗
PubMed2004

A genetic variation map for chicken with 2.8 million single-nucleotide polymorphisms.

We describe a genetic variation map for the chicken genome containing 2.8 million single-nucleotide polymorphisms (SNPs). This map is based on a comparison of the sequences of three domestic chicken breeds (a broiler, a layer and a Chinese silkie) with that of their wild ancestor, red jungle fowl. Subsequent experiments indicate that at least 90% of the variant sites are true SNPs, and at least 70% are common SNPs that segregate in many domestic breeds. Mean nucleotide diversity is about five SNPs per kilobase for almost every possible comparison between red jungle fowl and domestic lines, between two different domestic lines, and within domestic lines--in contrast to the notion that domestic animals are highly inbred relative to their wild ancestors. In fact, most of the SNPs originated before domestication, and there is little evidence of selective sweeps for adaptive alleles on length scales greater than 100 kilobases.

Alleles↗
PubMed2004

Synthesis and herbicidal activity of 2-cyano-3-(2-chlorothiazol-5-yl)methylaminoacrylates.

A series of 2-cyano-3-(2-chlorothiazol-5-yl)methylaminoacrylates were synthesized as herbicidal inhibitors of PSII electron transport. All of these compounds exhibited good herbicidal activities. In particular, (Z)-ethoxyethyl 2-cyano-3-isopropyl-3-(2-chlorothiazol-5-yl)methylaminoacrylate showed excellent herbicidal activities even at a dose of 75 g/ha. A suitable group at the 3-position of acrylate was essential for high herbicidal activity. 2-Cyanoacrylates containing a 2-chloro-5-thiazolyl group are a novel class of herbicides and display herbicidal activities comparable to existing analogues bearing chloropyridyl or chlorophenyl.

Cyanoacrylates↗
PubMed2004

Genes controlling seed dormancy and pre-harvest sprouting in a rice-wheat-barley comparison.

Pre-harvest sprouting results in significant economic loss for the grain industry around the world. Lack of adequate seed dormancy is the major reason for pre-harvest sprouting in the field under wet weather conditions. Although this trait is governed by multiple genes it is also highly heritable. A major QTL controlling both pre-harvest sprouting and seed dormancy has been identified on the long arm of barley chromosome 5H, and it explains over 70% of the phenotypic variation. Comparative genomics approaches among barley, wheat and rice were used to identify candidate gene(s) controlling seed dormancy and hence one aspect of pre-harvest sprouting. The barley seed dormancy/pre-harvest sprouting QTL was located in a region that showed good synteny with the terminal end of the long arm of rice chromosome 3. The rice DNA sequences were annotated and a gene encoding GA20-oxidase was identified as a candidate gene controlling the seed dormancy/pre-harvest sprouting QTL on 5HL. This chromosomal region also shared synteny with the telomere region of wheat chromosome 4AL, but was located outside of the QTL reported for seed dormancy in wheat. The wheat chromosome 4AL QTL region for seed dormancy was syntenic to both rice chromosome 3 and 11. In both cases, corresponding QTLs for seed dormancy have been mapped in rice.

Amino Acid Sequence↗
PubMed2002

Expression, purification and activity measurement of soluble BACE protein in E.coli.

To express BACE (beta-site APP cleaving enzyme), an aspartic protease related to Alzheimer's disease in E.coli to obtain the active protein after refolding and purification, the sequence for soluble form of BACE was inserted into prokaryotic expression vector pET11a. After expression in E.coli BL21(DE3), the protein was obtained as inclusion bodies, after refolding and purification. The proteolytic activity of the protein was measured by HPLC and MS. After refolding and purification, the protein exhibited beta-secretase activity by cleaving the synthetic peptide, which was designed according to the beta-secretase site at Swedish mutant of APP, and according Hanes method the kinetics constants for the synthetic peptide of BACE protein were measured. The study will facilitate BACE protein structure determination and inhibitor development efforts, which may lead to the evolution of promising and effective treatments for Alzheimer's disease.

Amyloid Precursor Protein Secretases↗