Search PubMed⌕ Search

Biomedical subjects

S Tang

Publications and source records attributed to S Tang.

At least 55 records · Page 3Linked to original sources
PubMed2001

[Isolation and characterization of a plasmid pTS50, which encodes nisin resistance determinant in Lactococcus lactis TS1640].

Three nisin-resistant Lactococcus lactis strains were screened from 197 samples of fresh milk on a selective medium (M17) supplemented with nisin, lactose and bromocresol purple, and were confirmed to have the nisin resistance determinant (nsr) by PCR amplification. Physiological and biochemical tests as well as Lactococcus lactis specific 16S rDNA sequence analysis revealed that the three strains all belong to Lactococcus lactis subsp. lactis. A large plasmid, pTS50, was identified in L. lactis subsp. lactis TS1640 which encodes resistance to nisin following electroporation of the total plasmids DNA into L. lactis MG1363. The molecular weight of plasmid pTS50 was estimated to be 47 kb by restriction analysis of BamHI, EcoRI, HindIII, NcoI, PstI and nsr was localized on a 1.9 kb EcoRI fragment by Southern hybridization.

Animals↗
PubMed2001

[Amplifying variable region gene of light chain of monoclonal antibody against human retinoblastoma by PCR].

OBJECTIVE: To acquire the variable region gene of light chain of monoclonal antibody against human retinoblastoma. METHODS: Total RNA were extracted from hybridoma cells secreting specific monoclonal antibody(McAb) against human retinoblastoma(RB), then transcripted reversely into cDNA with random primers. The variable region of the light chain(VL) gene fragments were ampliflied using polymerase chain reaction(PCR) method. Agrose gel electrophoresis was confirmed. RESULTS: 1.5% agrose gel electrophoresis indicated that VL gene was about 340 base pairs. CONCLUSION: The light chain variable region gene of the McAb against human RB was amplified successfully, which lays a good basis for construction of a recombinant antibody.

Antibodies, Monoclonal↗
PubMed2001

[The effects of perfluorodecalin on the anterior chamber angle and intraocular pressure in rabbits].

OBJECTIVE: To observe the effects of purfluorodecalin on the anterior chamber (AC) angle and intraocular pressure (IOP) in rabbits. METHODS: 0.05 ml perfluorodecalin was injected into right AC of 17 white rabbits and the same does of balanced salt solusion(BSS) was given to the controll group (6 rabbits). The IOP was measured before and 1, 2, 3, 4, 8, 12, 16 weeks after the injection. The treatment rabbits were sacrificed on the week of 1, 2, 4, 8 and 16 postoperatively. The eyes were enucleated and the histological examination was performed. RESULTS: There's no statistic IOP difference in the controll group before and after the injection of BSS. In treatment group, the IOP is similar to the preoperation level (11.62 +/- 6.35 mmHg) on the 7th postoperative day (10.82 +/- 3.17 mmHg, P < 0.05). A increment of IOP was measured at the week of 2 to 4, 8, 12, and 16 postoperatively (P < 0.01). Perfluorodecalin, having a 'fish eggs' or bubbles appearance, was noted in the inferior AC. Histopathologically, transparent single or fused vesicles and macrophages were accumulated at the AC angler in treatment rabbits. Some lymphocytes and neutrophils were aslo noted here. Trabeculae degenerated and intertrabecular space increased. CONCLUSIONS: The anterior chamber injection of perfluorodeclin could lead to a longstanding increase of IOP. Inflammatory reaction and trabeculae degeneration were seen in the anterior chamber angler.

Animals↗
PubMed2001

Experimental study on the effect of perfluorodecalin on rabbit corneas.

PURPOSE: To study the effects of perfluorodecalin on the cornea of the rabbit eyes. METHODS: Perfluorodecalin (0.05 ml/each) was injected into the anterior chambers of eighteen rabbit eyes. Corneal morphology and endothelial cells were monitored clinically by slit-lamp biomicroscope and specular microscope for 26 weeks. Animals were sacrificed in 1st, 2nd, 4th, 10th, 16th, 22nd, and 26th week after injection, respectively, and the corneas were examined under the light microscope. RESULTS: Perfluorodecalin droplets looking like "fish eggs" were found at about 1/4-1/2 of the corneal height in the inferior anterior chamber. Corneal opacification on the area contacted with perfluorodecalin was observed in five eyes five weeks after injection, and all in the 22nd week. Mutton fat KPs in one eye were seen in the 6th week firstly, and in all eyes in the 7th week. Corneal pannus formation in one eye was present in the 4th week, two eyes in the 5th week and three eyes in the 6th week. Retrocorneal fibrous membrane in one eye was detected at the 6th week and 3 eyes at the 7th week respectively. After injection of perfluorodecalin, endothelial cell density was significantly decreased (2,789 +/- 192 vs. 2,341 +/- 658, P < 0.01) and corneal thickness was increased. CONCLUSIONS: Perfluorodecalin injected into anterior chamber can lead to corneal damage and inflammatory reaction.

Animals↗
PubMed2001

Management of post-traumatic aniridia with retinal detachment.

PURPOSE: To reconstruct the anatomic and functional impairment in patients with post-traumatic aniridia, aphakia, and retinal detachment. METHODS: Four patients with unilateral aniridia and aphakia as well as retinal detachment as results of severe eye injuries underwent scleral buckling, vitrectomy, membrane peeling, endolaser photocoagulation, silicone oil or gas temponade, combined with iris diaphragm-IOL implantation. RESULTS: All four patients achieved successfully anatomic and functional reconstruction after surgery. During five to 22 months postoperative follow-up, all retinas remained attached. The final visual acuity increased from finger counting to 0.1-0.3. CONCLUSIONS: The combination of vitreoretinal surgery and iris diaphrgm-IOL implantation is an effective method for post-traumatic aniridia, aphakia and traumatic retinal detachment. It could ameliorate photophobia and improve the biocular vision. Furthermore, artificial iris diaphragm implantation could prevent silicone oil-endothelia contact and salvage silicone keratopathy.

Adult↗
PubMed2001

[The protein expression of p53 and bcl-2 in laryngeal squamous cell carcinoma].

OBJECTIVE: To detect the relationship of p53 and bcl-2 gene to laryngeal carcinoma. METHODS: p53 and bcl-2 protein expressions were examined in the specimens of 60 laryngeal carcinomas and 8 vocal cord polyps by immunohistochemistry method. RESULTS: Overexpressions of p53 and bcl-2 were found in the laryngeal carcinoma specimens; the positive rates of p53 and bcl-2 protein expression were 61.7%(37/60) and 43.3%(26/60), respectively. Negative results were observed in all the vocal cord polyp specimens. The positive rates of p53 and bcl-2 expression were related to the histological grade and cervical lymphatic metastasis of laryngeal carcinoma but not related to clinical stage and tumor types. CONCLUSION: The results of this study support the hypothesis that p53 and bcl-2 gene may be involved in the apoptosis of laryngeal carcinoma and they may play an important role in the pathogenesis of laryngeal cancer.

Adult↗
PubMed2000

Reversal of angiogenesis in vitro, induction of apoptosis, and inhibition of AKT phosphorylation in endothelial cells by thromboxane A(2).

Thromboxane A(2) (TxA(2)) causes platelet aggregation, vasoconstriction, and inhibition of endothelial cell (EC) migration and prevents vascular tube formation via its specific receptors (TP), of which there are two isoforms (TPalpha and TPbeta), both expressed in human ECs. In this study, we demonstrate that the TxA(2) mimetic IBOP increases apoptosis of human ECs and inhibits the phosphorylation of Akt kinase, an intracellular mediator required for cell survival. Treatment with IBOP destroyed EC networks formed on a basement membrane matrix in vitro. To distinguish the role of the TP isoforms, each isoform was expressed in TP-null ECs to create TPalpha and TPbeta ECs. IBOP induced apoptosis and inhibited phosphorylation of Akt kinase in both TPalpha and TPbeta. IBOP increased cAMP levels in TPalpha but not in TPbeta. Apoptosis induced by IBOP in TPalpha was not affected by either the adenylyl cyclase activator forskolin or the protein kinase A inhibitor 14-22 amide or H-89, whereas that in TPbeta was suppressed by forskolin and enhanced by the protein kinase A inhibitor 14-22 amide or H-89, suggesting that the TP isoforms differ in their signal pathways in mediating apoptosis. In conclusion, apoptosis may be the mechanism by which TxA(2)-mediated destruction of vascular structures in ECs occurs; although both TP isoforms induce apoptosis, possibly via inhibiting Akt phosphorylation, the signaling differs in each isoform, in that activation of the adenylyl cyclase pathway prevents apoptosis caused by TPbeta, but not by TPalpha, stimulation.

Adenylyl Cyclase Inhibitors↗
PubMed2000

Identification of diverse nerve growth factor-regulated genes by serial analysis of gene expression (SAGE) profiling.

Neurotrophic factors such as nerve growth factor (NGF) promote a wide variety of responses in neurons, including differentiation, survival, plasticity, and repair. Such actions often require changes in gene expression. To identify the regulated genes and thereby to more fully understand the NGF mechanism, we carried out serial analysis of gene expression (SAGE) profiling of transcripts derived from rat PC12 cells before and after NGF-promoted neuronal differentiation. Multiple criteria supported the reliability of the profile. Approximately 157,000 SAGE tags were analyzed, representing at least 21,000 unique transcripts. Of these, nearly 800 were regulated by 6-fold or more in response to NGF. Approximately 150 of the regulated transcripts have been matched to named genes, the majority of which were not previously known to be NGF-responsive. Functional categorization of the regulated genes provides insight into the complex, integrated mechanism by which NGF promotes its multiple actions. It is anticipated that as genomic sequence information accrues the data derived here will continue to provide information about neurotrophic factor mechanisms.

14-3-3 Proteins↗
PubMed2000

Comparative genomic hybridization in combination with flow cytometry improves results of cytogenetic analysis of spontaneous abortions.

More than 50% of spontaneous abortions (SAs) have abnormal chromosomes; the most common abnormalities are trisomy, sex chromosome monosomy, and polyploidy. Conventional cytogenetic analysis of SAs depends on tissue culturing and is associated with a significant tissue culture failure rate and contamination by maternally derived cells. Comparative genomic hybridization (CGH), in combination with flow cytometry (FCM), can detect numerical and unbalanced structural chromosomal abnormalities associated with SAs while avoiding the technical problems associated with tissue culture. Routine cytogenetic and CGH analysis was performed independently on tissue from 301 SAs. Samples shown to be chromosomally balanced by CGH were analyzed by FCM to determine ploidy. Of 253 samples successfully analyzed by both approaches, there was an absolute correlation of results in 235 (92.8%). Of the 18 cases with discrepancies between cytogenetic and CGH/FCM results, an explanation could be found in 17. Twelve samples produced a 46,XX karyotype by cytogenetics, whereas CGH/FCM demonstrated aneuploidy/polyploidy or a male genome, indicating maternal contamination of the tissue cultures. In two cases, where tetraploidy was demonstrated by cytogenetics and diploidy by FCM, tissue culture artifact is implied. In three cases, CGH demonstrated an aneuploidy, and cytogenetics demonstrated hypertriploidy. In one unexplainable case, aneuploidy demonstrated by CGH could not be detected by repeat CGH analysis, conventional cytogenetic, or FISH analysis. These results demonstrate that CGH supplemented with FCM can readily identify chromosomal abnormalities associated with SAs and, by avoiding maternal contamination and tissue culture artifacts, can do so with a lower failure rate and more accuracy than conventional cytogenetic analysis.

Abortion, Spontaneous↗
PubMed2000

Empirical evidence for differential organ reductions during trans-oceanic bird flight.

Since the early 1960s it has been held that migrating birds deposit and use only fat as fuel during migratory flight, with the non-fat portion of the body remaining homeostatic. Recent evidence from field studies has shown large changes in organ sizes in fuelling birds, and theory on fuel use suggests protein may be a necessary fuel during flight. However, an absence of information on the body condition of migrants before and after a long flight has hampered understanding of the dynamics of organs during sustained flight. We studied body condition in a medium-sized shorebird, the great knot (Calidris tenuirostris), before and after a flight of 5400 km from Australia to China during northward migration. Not only did these birds show the expected large reduction in fat content after migration, there was also a decrease in lean tissue mass, with significant decreases in seven organs. The reduction in functional components is reflected in a lowering of the basal metabolic rate by 42% [corrected]. Recent flight models have tried to separate the 'flexible' part of the body from the constant portion. Our results suggest that apart from brains and lungs no organs are homeostatic during long-distance flight. Such organ reductions may be a crucial adaptation for long-distance flight in birds.

Animals↗
PubMed2000

Fractal Morphology and Breakage of DLCA and RLCA Aggregates.

Latex aggregates, formed in 1 M McIlvaine buffer solution and 0.2 M NaCl solution, have been characterized in terms of aggregate size distribution and fractal morphology. This was achieved using three sizing techniques (image analysis, laser scattering, and electrical sensing) in which size distributions and fractal properties of the aggregates were measured. Estimates of fractal dimensions were made using the two-slope method based on dimensional analysis and the small-angle light scattering method. Aggregate suspensions were prepared using both water and a mixture of heavy water/ water as the solvent. The latter essentially eliminated sedimentation, which was observed after one day of aggregation when water alone was used as a solvent. Latex aggregates formed by diffusion-limited colloid aggregation (DLCA) and reaction-limited colloid aggregation (RLCA) had fractal dimensions close to 1.8 and 2.1, respectively. As observed through image analysis, DLCA aggregates possessed a loose tenuous structure, whereas RLCA aggregates were more compact. Disruption of both DLCA and RLCA aggregates has been investigated in laminar flow and turbulent capillary flow. The shear forces introduced by a laminar shear device with a shear rate up to 1711 s(-1) were unable to bring about aggregate breakup; shearing facilitates aggregate growth in the case of DLCA. However, latex aggregates were significantly disrupted after passage through a turbulent capillary tube at 95209 s(-1). Copyright 2000 Academic Press.

Journal Article↗
PubMed2000

Color Doppler sonographic findings in splenic hamartoma.

We present the gray-scale and color Doppler sonographic findings in a case of a splenic hamartoma in a 40-year-old man. Gray-scale sonograms showed a 2 x 2 cm, hypoechoic splenic mass that was homogeneous without evidence of cystic change or calcification. Color Doppler sonograms showed multiple radial blood-flow signals inside the mass, and spectral analysis confirmed arterial and venous flow. Arteriograms showed multiple small, hypervascular masses with fine tumor vessels and tumor stains within the spleen. Histologic analysis following a splenectomy showed dilated vessels and congestion consistent with the color Doppler sonographic findings.

Adult↗
PubMed2000

Correlation of ultrasonographic imaging of congenital muscular torticollis with clinical assessment in infants.

Congenital muscular torticollis (CMT) is a common problem affecting infants and children. There is a general lack of standard clinical classification or objective assessment methods. Ultrasonographic imaging of the sternomastoid muscle (SCM) has been carried out in a consecutive series of 436 infants less than 1 y old presenting with CMT over a 5-y period. All patients were classified into three clinical groups: postural torticollis, muscular torticollis and sternomastoid tumor. The severity of the torticollis was also expressed into four subgroups according to the degree of deficits in passive rotation of the neck. The ultrasonographic image of the affected SCM included the echogenicity, texture, motility, softness and the transverse and longitudinal extent of the involvement. The disturbance in the quantitative measurement of the transverse diameter of the lower and upper third of the SCM and the ratio of the measurement to the normal side was recorded. The qualitative and quantitative changes in the SCM image were found to correlate significantly with the clinical typing and severity of rotational deficits of the neck. Ultrasonographic imaging has important potential clinical application in helping the diagnosis, prognostication and monitoring of progress of CMT longitudinally.

Female↗