Biomedical subjects

G X Song

Publications and source records attributed to G X Song.

At least 19 recordsLinked to original sources

PubMed2001

[Sequence analysis of the late region of human papillomavirus type 6 genome].

OBJECTIVE: To study variations of genome late region of human papillomavirus type 6 (HPV-6) isolated from Chinese patients with condyloma acuminatum. METHODS: Using overlap PCR design, major capsid protein (L1) and minor capsid protein (L2) genes were separately amplified from clinical samples following HPV type determination, and were further assembled into HPV-6 genome late region sequences after inserting into plasmid and sequencing. RESULTS: Two sequences (GenBank accession number AY015006, AY015008) of HPV-6 late region were assembled, which are 2,869 bp long covering 35% HPV-6 genome and with complete open reading frames (ORFs) for L1 and L2. Compared with prototype sequence, nine point mutations were found, including four missense mutations, three of which were located in L2 ORF. Phylogenetic analysis indicated that the cloned sequences are classified into HPV-6b. CONCLUSIONS: HPV-6 genome late region, especially in L1 ORF, is very conserved (variation rate < 0.28%). The mutation from A to G at position 7081 in HPV-6 genome and from G to A at 7099 may represent region characteristics. This is the first report that describes sequence variations among genome late region of HPV-6 isolated from Chinese patients.

Condylomata Acuminata↗

PubMed1997

Responses of mature and aged sympathetic neurons to laminin and NGF: an in vitro study.

Whilst the potent effects of NGF and laminin on developing neurons are well documented, relatively little is known about the effects of, or altered availability of or altered responsiveness to, these substances on the growth of adult neurons. We have therefore examined this question using explant cultures of sympathetic neurons from the superior cervical ganglion (SCG) of mature and aged rats. Explants were grown on substrata containing different doses of laminin, either with or without added NGF in culture medium containing FCS. Individually, laminin and NGF had relatively small effects on neurite outgrowth and length, which tended to be reduced in old neurons. In contrast, laminin in the presence of exogenous NGF exerted a powerful effect on nerve growth which was substantially greater than the sum of the effects of the individual factors. This synergy was evident in all experimental groups and was greatest in old explants at high doses of laminin, where growth was comparable to that of mature neurons. The dose-response curve of old neurons to laminin in the presence of added NGF indicated reduced responsiveness. These results suggest that variations in the availability of laminin and/or exogenous NGF, together with altered patterns of neuronal responsiveness, may contribute to impaired neuronal plasticity in old age.

Aging↗

PubMed1994

[Magnetic resonance imaging in 80 cases of orbital tumors].

Magnetic resonance imaging (MRI) is a new medical imaging technique which has been used in evaluating ocular and orbital diseases in recent years. Owing to the high resolution of soft tissues and lesions, it is superior to ultrasound and computed tomography in the localization and characterization of an orbital tumor in diagnosis. In this paper, we analysed 80 cases of MR images of orbital tumors by which all the lesions were detected. Benign or malignant disorders were recognized in 59 cases and complete tumors with accurate localization were shown in 79 cases. The principles of MRI, signal intensity of various tumors and the indications of MRI were discussed.

Dermoid Cyst↗

PubMed1994

[Modern methods of examination in the diagnosis of orbital neurilemmoma].

The important symptoms in 58 cases of neurilemmoma were slow exophthalmos and visual impairment. The diagnosis was discussed and the values of B-scan, CT and MRI were analysed.

Adolescent↗

PubMed1991

A research for the relationship between human papillomavirus and human uterine cervical carcinoma. I. The identification of viral genome and subgenomic sequences in biopsies of Chinese patients.

Biopsies from 318 cases with squamous cell carcinoma of the uterine cervix, 48 with cervical and vulvar condylomata, 14 with cervical intraepithelial neoplasia (CIN), 34 with chronic cervicitis and 24 with normal cervical epithelium were collected from different geographic regions with different cervical cancer mortalities. The DNA.DNA dot-blot and Southern blot hybridization results show that there is a close relationship between HPV-16 and the uterine cervical squamous cell carcinoma in China. One very interesting observation is that the finding of HPV-16-homologous DNA differs significantly among five geographic regions, and corresponds with the mortalities from cervical cancer of these five regions. HPV-11 was found mainly in benign lesions. The rate of detection of HPV-16 in Chinese women increased from 8.3% in normal cervical epithelium to 20% in chronic cervicitis, 28% in cervical condyloma, 50% in CIN and 60.4% in cervical cancer. It is suggested that HPV-16 infection may be an etiological factor in the development of human cervical carcinoma. From the results of Southern blot hybridization, it appeared that HPV-16 DNA had been integrated into the genome of the host cell in cervical cancer. Whereas the HPV-16 DNA sequence was only present as an episome in normal cervical epithelium and cervical benign lesions. The rate of occurrence of E6-E7 genes is the highest (88.9%) compared with that of other subgenomic fragments of HPV-16 in specimens of human cervical cancer in China. This implies that E6 and E7 may be the oncogenic genes of HPV-16 and play an important role in the carcinogenesis of human cervical epithelial cells. The amplification and rearrangement of the c-myc protooncogene are closely associated with the occurrence of cervical cancer. The results presented here revealed that the activated c-myc oncogene may cooperate with HPV-16 in the carcinogenic processes.

Biopsy↗

PubMed1991

A research for the relationship between human papillomavirus and human uterine cervical carcinoma. II. Molecular genetic and ultrastructural study on the transforming activity of recombinant retrovirus containing human papillomavirus type 16 subgenomic sequences.

In order to elucidate the role of HPV-16 in the development of genital cancer, NIH3T3 cells were transfected by HPV-16 whole genome and its two early genes, E6-E7. Besides ordinary calcium phosphate/DNA coprecipitation technique, a newly designed recombinant retrovirus containing the HPV-16 genome or subgenomes was used to infect cells for transfer of the target genes. The transforming activities have been demonstrated to be most efficient when a bioengineering technique of this kind is used. HPV-16 DNA was proved to have transforming potential for NIH3T3 cells, and the DNA of HPV-16 was proved to undergo multisite integration into transformed cells and nude mice tumour cells. The E6-E7 open reading frames are sufficient for transforming NIH3T3 cells independently in vitro, which implies that E6-E7 open reading frames are transforming genes or even viral oncogenes of HPV-16. The RNA transcribed by the E6-E7 of HPV-16 was expressed in transformed cells and in tumour cells of nude mice. The use of a recombinant retrovirus for gene transfer in this study is much more efficient than that of calcium phosphate/DNA coprecipitation. The lack of a tissue-culture system suitable for HPV replication in vitro makes HPV gene recombination into a specially engineered retrovirus for viral-mediated gene transfer of particular significance for the possible application of viral carcinogenesis, both in vitro and in vivo, for basic and clinical research.

Animals↗

PubMed1991

[Comparison of ultrasound, computed tomography and magnetic resonance imaging in diagnosis of orbital disorders].

16 cases of confirmed orbital disorders, comprising orbital tumor 11 cases, inflammation 2 cases, ophthalmic Graves' disease 2 cases and carotid-cavernous sinus fistula 1 case, were studied with ultrasound, CT, and magnetic resonance imaging (MRI) in regard to identification and localization of the lesions. MRI excelled CT and ultrasound in histologic contrast resolution and spatial localization. The technique of MRI was particularly discussed.

Adolescent↗

PubMed1991

[Surgical treatment of lid retraction in Graves' ophthalmopathy].

Surgical treatment of lid retraction in Graves' ophthalmopathy consisted of resection of Müller's muscle and myotomy of Müller's muscle combined with intraoperative guided disinsertion of the levator palpebrae superioris from the tarsus. Among 10 eyes of 9 patients treated by the authors, 9 eyes achieved good cosmetic effect and corneal exposure was prevented during a follow-up of 3-42 months.

Adult↗

PubMed1990

[Digital subtraction angiography (DSA) in the diagnosis of orbital diseases].

DSA was used in confirming the diagnoses of 3 cases of arteriovenous aneurysm, 3 cases of arteriovenous communication in the orbit or the cavernous sinus, and 1 case each of internal carotid aneurysm and granular myoblastoma. The technique provided basis for the selection of surgical approaches. One case each of orbital apex inflammation, ophthalmic Graves disease and orbital varix displayed normal findings with DSA.

Adolescent↗

PubMed1990

[CT findings in 49 cases of primary orbital meningioma].

CT is an important method to demonstrate orbital tumors. 49 cases of primary orbital meningioma were shown by CT as of pyramidal shape or as tubular enlargement of the optic nerve. The CT numbers were +48-+108 Hu, and in 1 case, the enlarged optic nerve was of bony density. In 34 cases, the tumors were limited in the orbit, and the others extended into the cranial cavity or the temporal fossa. The relationship between the initial site of the tumor and the CT features, and the differential diagnosis were discussed.

Adolescent↗

PubMed1990

[CT scanning in the diagnosis and treatment of intraorbital dermoid cyst].

39 cases of intraorbital dermoid cyst were examined by CT scanning with characteristic features of heterogeneity in the cystic content with areas of negative CT value, nonenhancement by contrast media, and excavation of the orbital walls. The precise localization of the tumor is conducive to the selection of a proper surgical approach.

Adolescent↗

PubMed1988