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Biomedical subjects

Lei Shao

Publications and source records attributed to Lei Shao.

15 recordsLinked to original sources
PubMed2008

Juxtaglomerular cell tumor in an 8-year-old girl.

Juxtaglomerular cell tumor (JGCT) is an extremely rare renal neoplasm in the pediatric population. It is considered a benign tumor arising from the juxtaglomerular apparatus of the kidney. JGCT has characteristic clinicopathologic features, but its cytogenetic features are unknown. We report a case of JGCT in an 8-year-old female who presented with severe hypertension, elevated serum renin level, and a well circumscribed tumor in the right kidney. Protogranules of renin was identified in the cytoplasm of the tumor cells by electron microscopic examination. Fluorescence in situ hybridization revealed monosomy of chromosomes X, 6, 9, 11, 15, and 21.

Child↗
PubMed2006

Nephrogenic fibrosing dermopathy in children.

Nephrogenic fibrosing dermopathy (NFD) is an entity of unknown etiology that has only been reported in patients with impaired kidney function. It has characteristic diagnostic findings by skin biopsy and due to its systemic involvement in some reported cases, the term "nephrogenic systemic fibrosis" has been recently suggested as more appropriate for the nomenclature of this entity. There is no curative treatment currently available and very few cases have been reported in children. We hereby report two cases so as to alert pediatric health care providers about the existence of this disorder.

Adolescent↗
PubMed2006

Cloning and characterization of a bacterial iterative type I polyketide synthase gene encoding the 6-methylsalicyclic acid synthase.

Unusual polyketide synthases (PKSs), that are structurally type I but act in an iterative manner for aromatic polyketide biosynthesis, are a new family found in bacteria. Here we report the cloning of the iterative type I PKS gene chlB1 from the chlorothricin (CHL) producer Streptomyces antibioticus DSM 40725 by a rapid PCR approach, and characterization of the function of the gene product as a 6-methylsalicyclic acid synthase (6-MSAS). Sequence analysis of various iterative type I PKSs suggests that the resulting aromatic or aliphatic structure of the products might be intrinsically determined by a catalytic feature of the paired KR-DH domains in the control of the double bond geometry. The finding of ChlB1 as a 6-MSAS not only enriches the current knowledge of aromatic polyketide biosynthesis in bacteria, but will also contribute to the generation of novel polyketide analogs via combinatorial biosynthesis with engineered PKSs.

Acyltransferases↗
PubMed2006

Genetic characterization of the chlorothricin gene cluster as a model for spirotetronate antibiotic biosynthesis.

The biosynthetic gene cluster for chlorothricin (CHL) was localized to a 122 kb contiguous DNA from Streptomyces antibioticus DSM 40725, and its involvement in CHL biosynthesis was confirmed by gene inactivation and complementation. Bioinformatic analysis of the sequenced 111.989 kb DNA region revealed 42 open reading frames, 35 of which were defined to constitute the CHL gene cluster. An assembly model for CHL biosynthesis from D-olivose, 2-methoxy-5-chloro-6-methylsalicyclic acid, and chlorothricolide building blocks was proposed. This work represents cloning of a gene cluster for spirotetronate antibiotic biosynthesis and sets the stage to investigate the unusual macrolide biosynthesis including tandem Diels-Alder cyclizations, Baeyer-Villiger oxidation, and incorporation of an enoylpyruvate unit.

Amino Acid Sequence↗
PubMed2006

[Study of DNA damage of buccal mucosal cells after wearing casting alloy crowns].

OBJECTIVE: To test the corrosion behavior of three kinds of dental casting alloys and to investigate the effect of the released metal ions on the DNA damage of dog buccal mucosal cells. METHODS: Three kinds of frequently used dental casting alloys were used to make full crowns for dogs. The concentration of the released metal ions was measured after the restoration of 2 weeks, 1 month, 2 months and 3 months. The DNA damage of buccal mucosal cells was studied by the method of SCGE. RESULTS: The metal ions released from NiCr and NiCrBe were detected in buccal mucosal cells while the amount of the ions released from noble alloy (gold 58%) was too small to be detected. The DNA damage of mucosal cells increased after restoration of NiCr and NiCrBe crowns. CONCLUSION: The noble alloy (gold 58%) is most corrosion resistant of the three alloys and has good biocompatibility. The NiCr and NiCrBe are prone to corrode and have cytotoxicity to cells.

Alloys↗
PubMed2005

Silica nanotubes for lysozyme immobilization.

Silica nanotubes were synthesized and used as enzyme immobilization carriers. The immobilization profiles were described by the adsorption of lysozyme molecules from aqueous solution onto the hydrophilic silica surface. The driving force of the adsorption, structure changes in the immobilized lysozyme molecules, and enzymatic activities were investigated. A study of the zeta potentials of silica with and without the immobilized lysozyme showed that there was an increase in the isoelectric point with the increase in the loading amount of lysozyme. FTIR spectra indicated that protein secondary structure was maintained well in the immobilized molecules. It was observed that enzymatic activities first increased and then decreased with increasing surface coverage of silica nanotubes by lysozyme, which suggested that the overlap and aggregation of lysozyme molecules reduced enzymatic activities of the adsorbed lysozyme molecules at high surface coverage.

Adsorption↗
PubMed2005

CHMIS-C: a comprehensive herbal medicine information system for cancer.

A comprehensive herbal medicine information system for cancer (CHMIS-C) has been developed. The current version of the database integrates information on more than 200 anticancer herbal recipes that have been used for the treatment of different types of cancer in clinic, 900 individual ingredients, and 8500 small organic molecules isolated from herbal medicines. Furthermore, subsidiary databases of literature references and molecular targets have been constructed. A number of web-based searching tools have been developed and integrated into the information system for efficient data mining. The compounds in the database have been linked to the corresponding entries in the National Cancer Institute's database, and to a database of drugs approved by the U.S. Food and Drug Administration. This paper provides a description of the individual subsidiary databases, integration of the entire database, and data mining tools. We demonstrate that this comprehensive information system may be used as an effective informatics tool for anticancer drug discovery.

Antineoplastic Agents, Phytogenic↗
PubMed2005

Treatment of femoral head necrosis with free vascularized fibula grafting: a preliminary report.

Since October 2000, 56 hips in 48 patients with avascular necrosis of the femoral head were treated with free vascularized fibular transplants. The average follow-up was about 16 months. The Harris hip scores of all stages were improved during follow-up. Most femoral heads showed improvement (39 hips, 69.6%) or were at least unchanged (14 hips, 25.0%) on X-rays. The results show that a free vascularized fibular graft would be a valuable procedure for femoral head necrosis. By this method, we can avoid or delay progress of the disease, and improve the function of the hip and quality of life.

Adult↗
PubMed2005

[Surgical technique of modified free vascularized fibular grafting for treatment of osteonecrosis of the femoral head].

OBJECTIVE: To evaluate the surgical technique, clinical results, and the complications of modified free vascularized fibular grafting for the treatment of osteonecrosis of the femoral head. METHODS: From October 2000 to August 2004, 124 patients (139 hips) with osteonecrosis of the femoral head were treated with modified free vascularized fibular grafting. There were 83 males(93 hips) and 41 females (46 hips), with a mean age of 36.4 years (16-57). The disease was caused by trauma in 49 cases(54 hips), use of steroids in 29 cases (32 hips), consumption of alcohol in 19 cases (21 hips) and idiopathic condition in 27 cases (32 hips). Of 139 hips, 50 were classified as stage II ; 71 as stage II, 18 as stage IV according to Steinberg system; the Harris hip scores were 79.3, 69.3 and 58.4, respectively. At the operation, modified technique of the fibular osteotomy was adopted. A front-hip operative approach was designed and a modified technique of removing the necrotic bone in femoral head was applied. During operation, the duration of operation, the bleeding volume, and the length of incisions were recorded. The follow-up items included the results of X-ray examination, the Harris score of the hip, and the evaluation of the complications. RESULTS: The duration of the fibular osteotomy was 10 to 30 min (15 min on average). The duration of the total operation was 80 to 120 min (90 min on average). The length of incision at the hip was 6 to 12 cm (8 cm on average). The bleeding volume was 100 to 300 ml (200 ml on average). The average hospitalization days was 7 days. After operation, Harris hip scores in most cases were improved. According to postoperative X-ray, 62 hips (79.5%) were improved to different extents and 14 hips (17.9%) had no significant changes. Deterioration occurred in 2 hips (2.6%). CONCLUSION: The modified free vascularized fibular grafting has lots of virtues, such as less bleeding volume, more clear anatomic structure, more convenience for operation, less damage, less complications, and better results of function recovery. It is an effective method for treating osteonecrosis of the femoral head.

Adolescent↗
PubMed2004

Expression of WT-1, Bcl-2, and CD34 by primary renal spindle cell tumors in children.

The confident diagnosis of renal spindle cell tumors in children is often difficult. An immunohistochemical study of WT-1, Bcl-2, and CD34 was performed to determine their expression profiles and to assess the potential utility of these immunohistochemical markers in the differential diagnosis of 36 cases of renal spindle cell tumors of childhood. The cases included 11 stromal predominant Wilms tumors, 12 cellular mesoblastic nephromas, 9 clear cell sarcomas of the kidney (CCSK), and 4 monophasic synovial sarcomas. WT-1 was uniformly positive in primitive undifferentiated stromal Wilms tumors (6 of 6) and negative in the differentiating and differentiated stromal elements of Wilms tumors (0 of 5). WT-1 was also negative in cellular mesoblastic nephromas (0 of 12), CCSKs (0 of 12), and synovial sarcomas (0 of 4). Bcl-2 was expressed in all stromal Wilms tumors (11 of 11), all synovial sarcomas (4 of 4), some CCSKs (4 of 9), and none of the cellular mesoblastic nephromas (0 of 12). Although CD34 was absent in the tumor cells of all the tumors studied (0 of 36), CD34 immunohistochemistry nicely demonstrated the evenly distributed septal capillaries characteristic of CCSK in all 9 cases of this tumor. We conclude that a combination of WT-1 and Bcl-2 immunohistochemistry may aid in the distinction of stromal Wilms tumor, monophasic synovial sarcoma, cellular mesoblastic nephroma, and CCSK.

Antigens, CD34↗
PubMed2004

Fabrication of porous hollow silica nanoparticles and their applications in drug release control.

Preparation and characterization of porous hollow silica nanoparticles (PHSN) for controlled release applications were investigated. Through orthogonally designed experiments, the optimal synthesis conditions for the preparation of PHSN were obtained and the produced PHSN were characterized by BET, SEM, TEM and IR. Scanning and transmission electron microscopy images revealed their hollow shell-core structure and also demonstrated that the size and shape of PHSN are determined by the templating CaCO3 nanoparticles. The produced PHSN were applied as a carrier to study the controlled release behaviors of Brilliant Blue F (BB), which was used as a model drug. Being loaded into the inner core and on the surfaces of the nanoparticles, BB was released slowly into a bulk solution for about 1140 min as compared to only 10 min for the normal SiO2 nanoparticles, thus exhibited a typical sustained release pattern without any burst effect. In addition, higher BET of the carriers, lower pH value and lower temperature prolonged BB release from PHSN, while stirring speed showed little influence on the release behavior. It showed that PHSN have a promising future in controlled drug delivery applications.

Benzenesulfonates↗
PubMed2004

Feasibility of preparing nanodrugs by high-gravity reactive precipitation.

To study the feasibility of producing nanoparticles of organic pharmaceuticals using a novel high-gravity reactive precipitation (HGRP) technique, reactive precipitation of benzoic acid as a model compound was carried out in a rotating packed bed under high gravity. The main factors such as the rotating bed speed, concentration and volume flow rate of the reactants (sodium benzoate and HCl) affecting the particle size of the precipitate were studied. Particle size was measured by transmission electron microscopy. Benzoic acid was precipitated as nanoparticles as fine as 10nm. The particle size was decreased with increasing rotating bed speed, concentration and volume flow rate of the reactants. The formation of ultrafine particles was due to intensified micro-mixing of reactants in the rotating bed to enhance nucleation while suppressing crystal growth. The results have demonstrated the feasibility to produce nanodrugs by the principle of acid-base precipitating reaction using HGRP.

Benzoic Acid↗
PubMed2004

Preparation and characterization of porous hollow silica nanoparticles for drug delivery application.

Porous hollow silica nanoparticles (PHSNP) with a diameter of 60-70 nm and wall thickness of approximately 10nm were synthesized by using CaCO(3) nano-particles as the inorganic template. The characterization of PHSNP by TEM and BET indicated that PHSNP were uniform spherical particles with good dispersion, and had a specific surface area of 867 m(2)/g. The as-synthesized PHSNP were subsequently employed as drug carrier to investigate in vitro release behavior of cefradine in simulated body fluid. UV-spectrometry and TG analyses were performed to determine the amount of cefradine entrapped in the carrier. The BJH pore size distribution of PHSNP before and after entrapping cefradine was examined. Cefradine release profile from PHSNP followed a three-stage pattern and exhibited a delayed release effect.

Calcium Carbonate↗
PubMedDate not supplied

Web-based tools for mining the NCI databases for anticancer drug discovery.

In this paper, we describe the development of a set of integrated Web-based tools for mining the National Cancer Institute's (NCI) anticancer databases for anticancer drug discovery. For data mining, three different correlation algorithms were implemented, which included the commonly used Pearson's correlation algorithm available from the NCI's COMPARE program, the Spearman's and Kendall's correlation algorithms. In addition, we implemented the p-value test to evaluate the significance of the correlation results. These Web-based data mining tools allow robust analysis of the correlation between the in vitro anticancer activity of the drugs in the NCI anticancer database, the protein levels and mRNA levels of molecular targets (genes) in the NCI 60 human cancer cell lines for identification of potential lead compounds for a specific molecular target and for study of the molecular mechanism action of a drug. Examples were provided to identify PKC ligands using a lead compound and to identify potential ErbB-2 inhibitors using the mRNA levels of ErbB-2 in the NCI 60 tumor cell lines.

Antineoplastic Agents↗