Biomedical subjects

Guangyu Chen

Publications and source records attributed to Guangyu Chen.

9 recordsLinked to original sources

PubMed2006

ARCS: an aggregated related column scoring scheme for aligned sequences.

MOTIVATION: Biologists frequently align multiple biological sequences to determine consensus sequences and/or search for predominant residues and conserved regions. Particularly, determining conserved regions in an alignment is one of the most important activities. Since protein sequences are often several-hundred residues or longer, it is difficult to distinguish biologically important conserved regions (motifs or domains) from others. The widely used tools, Logos, Al2co, Confind, and the entropy-based method, often fail to highlight such regions. Thus a computational tool that can highlight biologically important regions accurately will be highly desired. RESULTS: This paper presents a new scoring scheme ARCS (Aggregated Related Column Score) for aligned biological sequences. ARCS method considers not only the traditional character similarity measure but also column correlation. In an extensive experimental evaluation using 533 PROSITE patterns, ARCS is able to highlight the motif regions with up to 77.7% accuracy corresponding to the top three peaks. AVAILABILITY: The source code is available on http://bio.informatics.indiana.edu/projects/arcs and http://goldengate.case.edu/projects/arcs

Algorithms↗

PubMed2006

Construction and direct immunization of eukaryotic expression plasmid encoding human soluble B lymphocyte stimulator.

B lymphocyte stimulator of the tumor-necrosis-factor family (BLyS) enhances B cell survival, a function indispensable to B cell maturation. This factor plays a crucial role in enhancing immune responses. Here, to study the primary immune effect of BLyS gene in animals, we constructed recombinant eukaryotic expression plasmid of the human soluble BLyS by using expression vector pcDNA3.1 (-). The recombinant plasmid pcDNA3.1BLyS was injected subcutaneously into BALb/C mice and this administration induced the sustained expression of human BLyS and specific IgG against the recombinant BLyS protein. This study shows that recombinant eukaryotic expression plasmid, pcDNA3.1BLyS, might be used in human gene therapy.

Animals↗

PubMed2006

Development of an immunoassay kit for detecting the alteration of serum B cell activating factor in thermally injured mice.

B cell activating factor (BAFF), a member of the family of tumor necrosis factor (TNF) ligands, is essential for the development of peripheral mature, long lived B lymphocytes. Previous studies were almost related to the function or mechanism of BAFF protein and there is little report about BAFF expression in thermally injured animals. Here, we developed a special ELISA kit to study the change of BAFF expression in thermally injured mouse model. It was shown that BAFF expression changed in double-phase. Peripheral BAFF level dropped rapidly after thermal injury and at 24 h of scald it was only 1/4 compared with that of the control group, 24 h later it began to rise up slowly and then returned to the normal level comparable to the control at 120 h.

Animals↗

PubMed2006

[Clinical application of the anterolateral thigh flap in 112 patients].

OBJECTIVE: To investigate the anatomic variations of the perforator vessels of anterolateral thigh (ALT) flap and the clinical indications. METHODS: From March 1985 to August 2004, the anterolateral thigh flap graft was performed in 112 patients. The clinical data were analyzed. There were 67 males and 45 females, aging from 5 to 65 years with an average of 38. 5 years. According to recipient site condition, four methods of flap harvesting were as follows: (1) 78 received free fasciocutaneous flaps; (2) 22 received free adipofascial flaps; (3) 5 received pedicled island fasciocutaneous flaps; (4) 7 received pedicled reverse-flow island fasciocutaneous flaps. Facial, neck, breast, extremity joint, plantar, and perineum defects were repaired and the effectiveness and donor site morbidity were evaluated. RESULTS: The blood supply of ALT flap came from the descending branch or transverse branch of the lateral circumflex femoral artery. The skin vessels were found to be septocutaneous perforators in 33% of flaps and to be musculocutaneous perforators in 77% of flaps. Of 112 flaps, 107 survived completely, the survival rate was 95.6% with little donor site morbidity. CONCLUSION: ALT flap is a versatile soft-tissue flap. If refined to perforator flap, it can achieve better results in reconstructing defect and minimizing donor-site morbidity.

Adolescent↗

PubMed2005

Primary immune effects of eukaryotic expression plasmids encoding two hyperactive mutants of human soluble B lymphocyte stimulator.

B lymphocyte stimulator (BLyS), a ligand belonging to the tumor necrosis factor (TNF) family, plays a critical role in regulating survival and activation of peripheral B cell populations during humeral immune responses. Among the TNF family members, BLyS is unique in that it contains an unpaired Cys residue (Cys146) at the corresponding position where some other members have about 37.5% (6/16) Ala or 37.5% (6/16) Val. Here, with eukaryotic expression vector pcDNA3.1(-), we mutated Cys146 to Ala or Val and constructed two mutant eukaryotic expression plasmids of the human soluble BLyS, pcDNA3.1BY-A and pcDNA3.1BY-V. Following repetitive subcutaneous injection of these expression plasmids in BALb/C mice, the wild-type and mutant BLyS proteins were detectable in the blood of treated animals over several weeks. In addition, the expression of these proteins induced specific IgG but not IgM responses. The implications of the results are discussed.

Animals↗

PubMed2004

Construction and function of two Cys146-mutants with high activity, derived from recombinant human soluble B lymphocyte stimulator.

B lymphocyte stimulator (BLyS) is a novel member of tumor necrosis factor (TNF) ligand family that is important in B cell maturation and survival. Previous studies were almost related to the function or mechanism of its wild type. Here, we constructed two site-directed mutants of the recombinant human soluble BLyS, the BY-A and BY-V, and found that BY-V ranked the highest whenever in the process of promoting proliferation of B lymphocytes in vitro or stimulating total serum IgG and IgM secretion in vivo. Besides, assays for the biological responses of human leukemic cell lines to BLyS, BY-A and BY-V demonstrated that they could suppress the proliferation of Raji cells but promote the growth of THP-1. The discovery of BY-V with high activity will help come to a conclusion that the mutation of Cys146 to Val146 might improve the biological activity of BLyS.

B-Cell Activating Factor↗

PubMed2002

[Three-dimensional observation of the vasculature in the anterolateral thigh adipofascial flap and its clinical applications].

OBJECTIVE: To investigate the blood supply patterns of the anteriorlateral thigh adipofascial flap for clinical applications. METHODS: To investigate the blood supply patterns of the anteriorlateral thigh (ALT) adipofascial flap, 16 fresh cadavers were anatomically examined by intraarterial injection of colored latex. Three-dimensional analysis of the vasculature of the subcutaneous adipofascial tissue was performed. Sixteen patients underwent microsurgical correction with the ALT adipofascial flap. Among them, there were fifteen with hemifacial atrophy, one with micromastia. RESULTS: The three-dimensional arterial structures of the ALT adipofascial flap were the same in all the cadaver specimens. Each layer of the adipofascial tissue was supplied by several blood vessels of the axial pattern, especially in the deep layer. Sixteen patients were successfully treated with this flap. The postoperative follow-up ranged from six months to eleven years. There was not postoperative flap necrosis or absorption of the fatty tissue. Stable restoration of the facial contour or the breast was achieved. The donor-site morbidity was minimal. CONCLUSION: The blood supply of the ALT adipofascial flap is reliable. A considerable amount of the fatty layer of the flap can be removed primarily. It is a preferable procedure for reconstructing soft tissue defects.

Adipose Tissue↗

PubMed2002

[Congenital absence of the vagina in 126 patients].

OBJECTIVES: To investigate the clinical features and therapeutic results of multiple approaches for congenital absence of the vagina, and to find out the prevention of complications and reconstruction method. METHODS: We analysed retrospectively 126 patients with congenital absence of the vagina from 1979 to 2002. RESULTS: Congenital absence of the vagina occurred in 31.25% urinary tract anomalies and 6.35% musculoskeletal anomalies. Of the 126 patients, 6 received 2 or more than 2 operations, the remaining recovered after reconstruction of the vagina by using the inferior abdominal wall skin flap and pudendal-thigh skin flap. CONCLUSIONS: The techniques should be selected according to the conditions of the patient and features of multiple approaches. Damage to the rectum and urinary tract should be avoided in addition to postoperative retraction or prolapse of flaps and stenosis of the vaginal orifice.

Adolescent↗

PubMed2002

[The influence of over-expansion on the blood supply of an axial-pattern flap].

OBJECTIVE: To investigate the influence of over-expansion on the viability and vascularity of an axial-pattern flap. METHODS: Tissue expanders were implanted subcutaneously on the buttock of the mini-pig. After over expansion, an axial-pattern over-expanded skin flap was elevated in the pig of the experimental group. The differences in flap survival, LDF, MDA content and fluorescein stain were observed between the control and the experimental groups. The vascular architecture changes were also recorded using histological and clearing specimen examination. RESULTS: The microcirculation in the distal segment of the axial flap was significantly weakened after over-expansion. There were injury manifestation, change in vessel distribution and reduction of vascular territory in the axial over-expanded flap. CONCLUSIONS: Over-expansion could cause chronic injuries to the axial vessel network and damage the blood supply of the axial-pattern flap.

Animals↗