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Biomedical subjects

H Yang

Publications and source records attributed to H Yang.

At least 811 records · Page 45Linked to original sources
PubMed1995

[Homology of the recombinant DNA of plasmid pDJH2 with the recombinant DNA probe of L. alstoni and analysis of its expression in Escherichia coli].

Dig-labeled recombinant DNA probe of L. alstoni which contains the entire structural OmpL1 gene was hybridized with the recombinant DNA of the plasmid named pDJH2 of the gene library of L. interrogans serovar lai strain 017. The result showed a high degree of homology among them; expression of recombinant DNA of pDJH2 was achieved by beta-D-galactosidase (IPTG) induction in E. coli. The molecular weight of this product is 68kd. Then they were treated with proteinase K and subjected to SDS-PAGE. The results showed it is a protein in nature. Using the specific monoclonal antibody E4B7D5 on immunoblotting and specific polyclonal antibody on dot-ELISA assay, we investigated the immune reaction and noticed that protein 68kd might be an antigen in character. E. coli which contains the recombinant plasmid pDJH2 were injected into BALB/c mice. Then the mice were challenged by leptospires of the strong virulence strain 017, but all the infected mice survived. In this paper, we first report the expression of recombinant DNA of L. interrogans serovar lai strain 017 in E. coli when injected with IPTG, and immunoprotection of BALB/c mice which were injected with the expression against the infection of L. interrogans serovar lai strain 017. pDJH2 may be the first recombinant for which the gene has been cloned and its expression product 68kd may be the immunoprotective antigens.

Animals↗
PubMed1995

[Localization of insulin-like growth factor I in the upper end of human fetal femur].

The localization of insulin-like growth factor I in the upper end of the human fetal femur was studied by immunohistochemistry on the undecalcified bone sections. Certain numbers of chondrocytes in germinal, proliferating and hypertrophic zones of the epiphysial growth plates, some osteoblasts and a few osteoclasts were immunoreactive to the antibody to IGF-I. The end-product of the DAB reaction was deposited in the osteoid and bone matrix of metaphysis. Also presented is a discussion on the local effects of IGF-I on the chondrocytes, osteoblasts and osteoclasts.

Femur↗
PubMed1995

[Isolation and identification of extrem thermophilic bacteria from hot springs of Sichuan and Tibet].

Eleven strains of extrem thermophilic bacteria belonging to the Bacillus Stearothermophiles were isolated from the hot springs of Sichuan and Tibet. The cells were gram-positive, sporulating and motile. The optimum temperature for growth was between 65 degrees C to 70 degrees C; the maximum 94 degrees C, and minimum 40 degrees C. The colour of colony was yellow to bright orange. The G+C content of the DNA in strains has been found to be in the range 48.4-53.15 mol%.

China↗
PubMed1995

[Assessment of effectiveness of AgSD-ZnSD-Azone cream, negative ion irradiation and "moisture burn ointment" in prevention of burn wound infection as judged by changes in LPS, TNF and ET levels].

40 Wistar rats were scalded resulting in 15% TBSA full-thickness burn. Pseudomonas aeruginosa (10(9)/ml) was seeded on the wounds. The animals were divided into 4 groups. AgSD and ZnSD (with Azone) cream was applied to the wounds in the group I. The wounds were irradiated with negative ion current in the group II. The "moisture burn ointment" was applied to the wounds in the group III. Group IV consisted of controls without any treatment. Judging by changes in levels of LPS, TNF and ET, it was shown that the best result was obtained in the group I and II. The "moisture burn ointment" group yielded the poorest results.

Animals↗
PubMed1995

[A study on combined treatment with ANP and dopamine in acute renal failure in rats].

Acute renal failure (ARF) model was made by intraperitoneal injection of cisplatin at a dosage of 10mg/kg. After the procedure, the rats were given atrial natriuretic polypeptide (ANP) and dopamine (DA) as well as ANP or DA individually. The results indicated that combined treatment with ANP and DA was more effective for improvement of renal function in ARF (increase of GFR) than individual treatment with either ANP or DA. Dopamine can effectively reverse the side-effect of hypotension of ANP.

Acute Kidney Injury↗
PubMed1995

[Primary lymphomas of bone: a clinicopathologic study of 22 cases].

UNLABELLED: 22 cases of primary lymphoma of bone (PLB) were reported. Multiple bone involvement in two patients, singular bone in twenty patients. One case had regional lymph node involvement. Radiological examination revealed 91% had diffuse lytic lesions. Histological typing was performed according to working formulation. 15 formalin fixed paraffin embedded PLB specimens were studied immunohistochemically by use of the avidin-biotin-peroxide complex (ABC) method to label monoclonal antibodies. RESULTS: Ten neoplasms were B-cell type, there were T-cell type, the two remaining cases did not express. The ratio of primary lymphomas in this study in extranodal lymphomas is three times that reported in Japan and also higher than that reported in north America in recent years. The proportion of T-cell type is also higher than that reported in Japan. Differential diagnosis and several factors which influence immunostaining were also discussed.

Adolescent↗
PubMed1995

Characteristics of reversal optic cupping in adults glaucoma after reduction of intraocular pressure.

PURPOSE: According to Quigley's hypothesis the dense of connective tissue is the least and the pores of the lamina cribrosa are the largest at the superior and inferior poles of the lamina cribrosa, therefore they are the most vulnerable location to be involved in the characteristic glaucomatous optic nerve damage. To get clinical evidence for the hypothesis, the reversal of optic cup in adults glaucoma after reduction of intraocular pressure (IOP) was examined. METHODS: The stereoscopic flicker comparison on with computerized image system was used to monitor the optic cup's changing, 2 serial superposed stereo pairs were displayed alternatively and rapidly and the changing parts appeared moving Under the stereoscopic observation, the changes of 3-dimension optic cup could be seen and the false positive phenomena caused by photographic angle variation, vascular pulsation could be differentiated from the characteristic change of the cup. Stereo fundus photographs were taken from 31 eyes with hypertension glaucoma before and after treatment of reduction of IOPs which was either diamox administration or trabeculectomy. RESULTS: The result showed that the reversal of optic cups after reduction of IOPs were mostly asymmetrical, especially at the inferior and/or superior poles. By multiple stepwise regression, it is known that the amount of the change is only correlated with the initial elevated IOP. CONCLUSIONS: The study indicated that it was the distortion and deformity of the lamina cribrosa leading to shearing stress that results in glaucomatous characteristic damage in structure and function. The individual tolerance of the lamina cribrosa to the high intraocular pressure and the locations of individual vulnerable at the optic nerve head are various.

Adolescent↗
PubMed1995

[Unstable Jefferson variant atlas fractures: an unrecognized cervical injury].

Nine cases of unstable Jefferson variant atlas fractures were treated with nonoperative external immobilization between 1989 and 1993. All of them were studied by plain films and CT scans. Seven cases had three breaks of the atlas ring. One case had unilateral anterior arch fracture, associated transverse ligament tear and quadriplegia. The other case had Jefferson, Hangman, C3pedicle burst fractures and C3,4dislocation. All of the fractures were unstable or potentially unstable. Despite the abnormal open month view in all cases, the plain films showed minimal abnormalities, requiring CT for definite diagnosis. Follow-up for average of 16 months showed the 7 cases showed the fractures healed with good bone bunion, complete mobility and no residual pain.

Adolescent↗
PubMed1995

[The direct repair of the defect and grafting with single segment reduction fixation system in the treatment of lumbar spondylolysis and spondylolisthesis].

We designed lumbar spondylolysis and spondylolisthesis single segment reduction fixation system according to neural arch measured in the 46 dried specimen. The biomechanical tests showed that its strength is 1.6 times that of Hefti's technique, 2.7 times that of Salib's technique. It used contacted point lamina by lamina hook as fulcrum, through lever and pedicle screw to pull back olisthetic vertebrae. 18 patients were treated with this method. The displacemen rate was 26.67% before operation and 3.38% after operation. The height of disc was 14.94 mm before operation and 17.08 mm after operation. 15 patients were followed up for 12 months. By Henderson standard, excellent result was moted in 13 patients, good in 1 and fair in 1. We conclude that LSRF has good reduction and rigid fixation and it is a new technique for lumbar spondylolysis and spondylolisthesis.

Adult↗
PubMed1995

[The application of the pattern visual-evoked potential in the diagnosis and treatment of amblyopia].

PURPOSE: To research into the value of the application in the diagnosis and treatment of amblyopia, and to discuss the mechanism of amblyopia. METHODS: The subjects were divided into three groups: 108 amblyopia eyes; 180 normal eyes and 26 amblyopia eyes during the treatment with Madopar. PVEP was observed with black-white checks pattern-reversal stimulation at several spatial frequencies (30', 60', 90'). RESULTS: P1 latency of the amblyopia eyes prolongs at the high frequency (30' angle of view), in which the occurrence rate of abnormal PVEP is 68.5%. Through detecting PVEP during the treatment of amblyopia with Madopar, we found P1 latency shortened and amplitude increased (P < 0.05). CONCLUSION: It is better to use P1 latency to observe the visual function of patients with amslyopia with stimulation at 30' angle of view. PVEP is an important objective index in diagnosis and evaluating the curative effect of amblyopia.

Adolescent↗
PubMed1994

The triple-helical region of human type XIX collagen consists of multiple collagenous subdomains and exhibits limited sequence homology to alpha 1(XVI).

We previously isolated a clone from a human rhabdomyosarcoma (RH) cDNA library coding for a collagen chain different from those constituting the 18 reported types (Myers, J. C., Sun, M. J., D'Ippolito, J. A., Jabs, E. W., Neilson, E. G., and Dion, A. S. (1993) Gene (Amst.) 123, 211-217). The sequence translated to a 186-amino acid noncollagenous region, a 524-residue three-subdomain collagenous region, and a presumed 8-amino acid COOH-terminal peptide. To further elucidate the primary structure of this collagen, we have now determined the sequence of additional cDNA clones. Overlapping 3' clones, found to diverge exactly where the noncollagenous 8-residue COOH sequence began, encode two additional collagenous subdomains of 168 and 70 residues and a 19-residue COOH-terminal peptide. Analysis of genomic DNA spanning the region in question revealed several 45- and 51-base pair exons linked by 4 introns totaling over 5 kilobases (kb). A 2-kb intron, absent from the clones coding for the extended collagenous region, was used in Northern blot hybridization to detect an apparently prevalent splicing intermediate 2 kb larger than the major 12.4-kb RH transcript. Therefore, the triple-helical region of this collagen chain is likely to be composed of 832 amino acids divided into five collagenous subdomains separated by 20-44 residue interruptions. Two interruptions are similar in sequence and position to those located in the type XVI chain. Furthermore, the arrangement of 2 cysteines near the COOH terminus and two imperfections in collagenous subdomain 1 are conserved in the related subclass composed of type IX, XII, XIV, and XVI collagens. However, in contrast to the COOH-terminal interchain bridging in this latter collagen group, molecular modeling strongly predicts that the cysteines in RH collagen participate in intrachain disulfide bonds. Taken together, the data clearly show that RH collagen does not represent another chain of one of the known collagen types. We propose that it be designated the alpha 1 chain of type XIX collagen.

Amino Acid Sequence↗
PubMed1994

A genetic polymorphism within the third poly(A) signal of the DHFR gene alters the polyadenylation pattern of DHFR transcripts in CHL cells.

Two polymorphic dihydrofolate reductase (DHFR) alleles, termed 20 K and 21 K, exist in Chinese hamster lung cells. Three major transcripts of different lengths are transcribed from each allele, and the expression of these transcripts differs dramatically between the alleles as a result of differential utilization of three poly(A) sites. Transcripts from the 20 K allele are preferentially polyadenylated at the first poly(A) site, while those from the 21 K allele are preferentially polyadenylated at the third site. In this study, transient expression experiments were used to demonstrate that a 2.1 kb genomic fragment containing the three DHFR poly(A) sites is sufficient to reproduce the allele-specific polyadenylation pattern on transiently expressed CAT-DHFR transcripts in COS cells. Site-directed mutagenesis allowed identification of the sequence elements which are responsible for this allele-specific polyadenylation. These studies indicate that a single-base change in the third poly(A) signal sequence, which alters the consensus AAUAAA signal in the 21 K allele to a weak AAUAAU signal in the 20 K allele, is primarily responsible for the dramatic difference in polyadenylation between the two alleles. Thus, as a result of this single-base change in the third poly(A) signal sequence, utilization of the first poly(A) site, located 1.2 kb upstream, changes dramatically.

Animals↗
PubMed1994

Selection for the expression of one form of Chinese hamster dihydrofolate reductase over another during growth in methotrexate.

Two mammalian expression plasmids, each carrying a cDNA encoding a different allele of dihydrofolate reductase (DHFR) present in the Chinese hamster lung cell line DC-3F, were constructed. These simian virus 40 promoter-enhancer-based plasmids, designated pSVA75 and pSVMQ19, are identical except for a G-->A transition at nucleotide 286 of the DHFR coding sequence. Due to this change, the enzyme expressed by pSVA75 contains Asp95, while the enzyme expressed by pSVMQ19 has Asn95 [Melera et al., J. Biol. Chem. (1988) 1978-1990]. Both forms of the enzyme are catalytically equivalent and are produced to similar levels in DC-3F cells [Yu and Melera, Cancer Res. (1993) 6031-6035; H.Y., A.H. and P.W.M., in preparation]. Clonal cell lines expressing one or the other DHFR allele were obtained via transfection of DHFR- Chinese hamster ovary cells, and 74 clones of each type isolated. These were pooled and divided into 40 aliquots, each of which was then subjected to selection by growth in sequentially increasing concentrations of methotrexate (MTX). Analysis of the resulting drug-resistant populations revealed that cells producing Asp95 DHFR dominated with an overall frequency of 3:1, and therefore, under these growth conditions, display a selective advantage over those producing Asn95 DHFR. These data extend previous observations showing that independent selections of the heterozygous parent cell line DC-3F in MTX result in threefold more MTX-resistant lines overexpressing the Asp95-encoding DHFR allele than the Asn95-encoding DHFR allele.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1994

The FLI-1 and chimeric EWS-FLI-1 oncoproteins display similar DNA binding specificities.

Although recent data have demonstrated that the chimeric EWS-FLI-1 cDNA isolated from cases of Ewing's sarcoma can transform NIH 3T3 cells, little is known about the basis for this transformation. Since FLI-1 and EWS-FLI-1 contain an Ets domain, both proteins may act as sequence-specific transcription factors. Here the DNA binding properties of FLI-1 and EWS-FLI-1 have been examined. An epitope-tagging strategy was developed to determine the optimum DNA-binding sequence of FLI-1. The alignment of cloned binding sequences showed a consensus DNA-binding site of ACCGGAAG/aT/c. This consensus sequence shows greater specificity for sequence 5' of the GGAA core site than those of other Ets proteins. Using several truncated forms of FLI-1, we show that the Ets domain is necessary and sufficient for the DNA binding specificity of FLI-1. The EWS-FLI-1 protein displayed the same DNA binding specificity and affinity as FLI-1 did. Despite their DNA binding similarities, the EWS-FLI-1 translocation product is likely to have a distinct pattern of expression from that of FLI-1 since the translocation results in the replacement of the 5' regulatory region of Fli-1 with that of EWS. Consistent with this we found that Fli-1 mRNA expression in lymphocytes was high in quiescent cells and disappeared upon activation while EWS mRNA expression was low in resting cells and increased in activated T cells. In summary, our data suggest that EWS-FLI-1 might act through the same target genes normally regulated by FLI-1, and EWS-FLI-1-induced transformation may result from dysregulation of FLI-1 target genes during cell proliferation and differentiation.

3T3 Cells↗
PubMed1994

Luffin-S--a small novel ribosome-inactivating protein from Luffa cylindrica. Characterization and mechanism studies.

We purified and characterized a novel RIP (ribosome inactivating protein), Luffin-S from the seeds of Luffa cylindrica. Different from Luffin-A and B, which are RNA N-glycosidases with molecular weights of 27 and 28 kDa, respectively, Luffin-S has an M.W. of only approx. 10 kDa, much smaller than any other RIPs so far investigated. Its abundant resources, toxicity similar to TCS in a cell-free protein synthesis system and unique mechanism as phosphodiesterase, like alpha-sarcin, promisingly make it a potential toxic moiety of immunotoxin.

Amino Acids↗
PubMed1994

Prepro-TRH-(160-169) potentiates gastric acid secretion stimulated by TRH microinjected into the dorsal motor nucleus of the vagus.

Prepro-TRH-(160-169) (Ps4), one of the predicted connecting peptides of pro-TRH, potentiates TRH-induced TSH release in vivo and in vitro. The influence of Ps4 on TRH in medullary nuclei-induced vagal stimulation of gastric acid secretion was studied in urethane-anesthetized rats with gastric cannula. Ps4 injected into the dorsal motor nucleus of the vagus (DMN) (200 ng) did not influence basal gastric secretion. Ps4 (100, 150 and 200 ng) co-injected with TRH (50 ng) into the DMN potentiated the acid response to TRH by 14%, 76% and 182% respectively while prepro-TRH-(178-199) (Ps5, 438 ng) had no effect. Ps4 (200 ng) co-injected with TRH into the nucleus ambiguus did not modify TRH (50 ng)-induced acid secretion. These results indicate that Ps4 potentiates TRH in the DMN-evoked gastric acid secretion through an action that is peptide and site specific.

Animals↗