Biomedical subjects

Lei Xie

Publications and source records attributed to Lei Xie.

24 records · Page 2Linked to original sources

PubMed2004

[Minimally invasive technique of parotidectomy for benign parotid tumors].

OBJECTIVE: To evaluate a minimally invasive technique of parotidectomy in treatment of benign parotid tumors. METHODS: This retrospective review included 49 patients with benign parotid gland tumors. The modified technique included incision, flap elevation, facial nerve dissection, the great auricular nerve preservation and postoperative disposal. RESULTS: All tumors were resected completely. The operation lasted 1.5 approximately 2.5 h; the average length of incisions was from 5.5 cm to 7.5 cm, and the average postoperative hospital stay was 4 days. There were no permanent facial nerve injury, no obvious scars and no depressed deformity observed postoperatively. During the 6 months approximately 5 years following-up, no tumor recurrence was found. CONCLUSION: The minimally invasive technique of parotidectomy reduces the disadvantages of the traditional procedure, and improves the quality of operation.T.

Adenoma, Pleomorphic↗

PubMed2004

[Endoscope-assisted parotidectomy for benign tumors via a short hidden auricular incision].

OBJECTIVE: To evaluate a technique of endoscope-assisted parotidectomy for benign tumor via a short hidden auricular incision. METHODS: Twenty-six volunteer patients were selected for the new approach, 16 with mixed tumor, 9 Warthin's tumor and 1 lymphoepithelial cyst. The tumor size was 1.6 approximately 3 cm (average 2.2 cm) and the incision ranged 3.5 approximately 5.5 cm(average 4.5cm) divided into two parts: 1) basic segment--started from anterio-superior crease of tragus, went downward along tragal margin and pre-earlobial fold,and stopped at earlobe root; 2) extended segment--went from earlobe root, curved down posterio-inferiorly. The length of the latter was generally not beyond 1 cm. The procedure began with raising the myo-cutaneous flap and dissecting the whole posterior portion of the gland. Thus, two working spaces needed for endoscopic manipulation could be artificially created with suitable retracting instruments. Endoscopic view was then established, and the surgeons operated continuously in the later steps. Modified techniques, such as the antegrade facial nerve dissection, retrograde great auricular nerve dissection and direct coagulate-cut method with ultrasonically activated scalpel, were employed to archive the goals of endoscopical nerve preservation and tissue resection. RESULTS: All tumors were entirely removed. No postoperative paralysis occurred, excepting 1 case who suffered from an temporary paralysis for two months. The appearance was good due to overlapping the short scar onto the irregular line of auricular contour and hiding its lowest part in the earlobe shadow. CONCLUSIONS: Parotidectomy for benign tumors could be safely done via a much-shortened incision, assisted by an endoscope. The postoperative stress of patients can be obviously reduced with the minimally invasive manipulation and the good appearance.

Adenolymphoma↗

PubMed2003

On the role of structural information in remote homology detection and sequence alignment: new methods using hybrid sequence profiles.

Structural alignments often reveal relationships between proteins that cannot be detected using sequence alignment alone. However, profile search methods based entirely on structural alignments alone have not been found to be effective in finding remote homologs. Here, we explore the role of structural information in remote homolog detection and sequence alignment. To this end, we develop a series of hybrid multidimensional alignment profiles that combine sequence, secondary and tertiary structure information into hybrid profiles. Sequence-based profiles are profiles whose position-specific scoring matrix is derived from sequence alignment alone; structure-based profiles are those derived from multiple structure alignments. We compare pure sequence-based profiles to pure structure-based profiles, as well as to hybrid profiles that use combined sequence-and-structure-based profiles, where sequence-based profiles are used in loop/motif regions and structural information is used in core structural regions. All of the hybrid methods offer significant improvement over simple profile-to-profile alignment. We demonstrate that both sequence-based and structure-based profiles contribute to remote homology detection and alignment accuracy, and that each contains some unique information. We discuss the implications of these results for further improvements in amino acid sequence and structural analysis.

Amino Acid Sequence↗

PubMed2003

Using multiple structure alignments, fast model building, and energetic analysis in fold recognition and homology modeling.

We participated in the fold recognition and homology sections of CASP5 using primarily in-house software. The central feature of our structure prediction strategy involved the ability to generate good sequence-to-structure alignments and to quickly transform them into models that could be evaluated both with energy-based methods and manually. The in-house tools we used include: a) HMAP (Hybrid Multidimensional Alignment Profile)-a profile-to-profile alignment method that is derived from sequence-enhanced multiple structure alignments in core regions, and sequence motifs in non-structurally conserved regions. b) NEST-a fast model building program that applies an "artificial evolution" algorithm to construct a model from a given template and alignment. c) GRASP2-a new structure and alignment visualization program incorporating multiple structure superposition and domain database scanning modules. These methods were combined with model evaluation based on all atom and simplified physical-chemical energy functions. All of these methods were under development during CASP5 and consequently a great deal of manual analysis was carried out at each stage of the prediction process. This interactive model building procedure has several advantages and suggests important ways in which our and other methods can be improved, examples of which are provided.

Algorithms↗

PubMed2003

[Antitumor effects of electrothermal and electrochemical therapy on mice with sarcoma180].

OBJECTIVE: To explore the anti-tumor effects and the mechanism of a new treatment for Sarcoma180 in mice using both hyperthermia (H) and electrochemical therapy (ECT). METHODS: A group of mice with Sarcoma180 (1 cm in diameter) were divided randomly into four groups and given different treatments: Control, ECT alone, H alone and electrothermal & electrochemical therapy (ETECT). The volumes of the tumors were calculated everyday after treatment. The tumor tissues were examined morphologically at 0, 6, 24 and 72 hours after treatment. RESULTS: The tumors treated with ETECT were completely destroyed, and did not recur within a period of ten days by pathological examination. Results of this group were significantly different with the other groups (P<0.01). However, recurred tumors were found in 6 mice of H group and 5 mice of ECT group, respectively. CONCLUSIONS: Based on the results obtained, ETECT induced by ETECD (D-device) is an effective way to eliminate cancer. It is capable of completely destroying cancer cells in a short time. The rate of Sarcoma180 inhibition is 100%, and malignant cells can't recur. The research provided theoretical and experimental bases for the treatment of oral cancer by a new approach to treat oral cancer.

Animals↗

PubMed2003

[Using ultrasonically activated scalpels as major instrument for vessel dividing and bleeding control in minimally invasive video-assisted thyroidectomy].

OBJECTIVE: To establish new techniques on the control of vessel dividing and bleeding in minimally invasive video-assisted thyroid surgeries. METHODS: One hundred and seventy volunteer patients with nodular goiter, adenoma and Graves' disease consecutively received the endoscopic thyroid operation according to Miccoli's mode from April 2002 to June 2003. The approach was designed to use ultrasonically activated scalpels [Harmonic Scalpel (R), Johnson & Johnson, USA] as a major, suction-dissector or others as supplementary instruments during the whole process. During the operations, two methods, "sequenced dissect-coagulate-cut" and "pre-coagulation + interlaced cut-suck-coagulate-dissect", were employed and separately evaluated for their safety or efficacy. RESULTS: All of the procedures, except that 2 (their lesions were proven to be "cancer" by frozen section and need different treatment), were successfully completed. None of them were interrupted and converted to open surgery due to uncontrolled bleeding or severe postoperative hematoma. Branches of major thyroid vessels can be directly divided by ultrasonic scalpel without ligation or using hemoclips, supposing the technique of "sequenced dissect-coagulate-cut" method was strictly used. Bleeding during intra-gland dissection can be effectively controlled by the combined techniques of precoagulation of the vessels and the capsule vessel network near and around the incision, and then, by coordinating manipulation with a special multiple functional ultrasonic scalpel and a suction-dissector, supposing the technique of "interlaced cut-suck-coagulate-dissect" was properly employed. CONCLUSIONS: Using ultrasonic scalpels as major, suction-dissector or others as supplementary instruments, manipulating cooperatively during the whole process, can be an ideal fashion in the site of a narrow gasless working space via a small single incision in anterio-inferior neck. And this may dramatically simplify the manipulation, and hence greatly reduce the operative difficulty. The reforms resolved two key technique problems in Miccoli's endoscopic operation: vessel-dividing and bleeding-control, therefore, laying a sound basis for the clinical application of this special approach.

Adolescent↗