Search PubMed⌕ Search

Biomedical subjects

R Sun

Publications and source records attributed to R Sun.

At least 145 records · Page 8Linked to original sources

[Effect of 764-3 and ligustrazine on collagen content of extrapulmonary arteries during chronic hypoxia].

OBJECTIVE: Effect of two antifibrotic Chinese drugs, 764-3 and ligustrazine, on collagen content in chronic hypoxic pulmonary hypertensive extrapulmonary arterial wall were examined. METHODS: Since collagen contains more than 10% hydroxyproline by weight and in other proteins there are almost no hydroxyproline, collagen content was expressed as micrograms of hydroxyproline. Hydroxyproline was determined by calorimetric method after oxidized by chloramine T. RESULTS: Both 764-3 and ligustrazine significantly inhibited the increase of pulmonary arterial pressure and elevation of hydroxyproline content in extrapulmonary arterial wall during chronic hypoxia. CONCLUSIONS: 764-3 and ligustrazine may be two hopeful therapeutic drugs for chronic hypoxic pulmonary hypertension.

Animals↗

Sex determination by polymerase chain reaction on mummies discovered at Taklamakan desert in 1912.

Sex determination was performed by the polymerase chain reaction (PCR) on eight adult mummies and one child mummy which were discovered at Taklamakan desert in 1912 and now belong to the Lüshun Museum in China. Archaeologically, these mummies were humans living in the seventh century, that is, more than 1300 years ago. Putative sex determination was performed based on external morphology for six of the eight adults, but it was impossible for the other two adults and one child mummy due to marked destruction on the external morphology. Hair, muscle and skin samples were then collected from each adult mummy, and skin and rib samples from the child mummy. Forty PCR cycles were performed as follows: denaturation at 94 degrees C for 40 s, annealing at 55 degrees C for 30 s and extension at 72 degrees C for 1 min. The primer and PCR reaction mixture were prepared according to the report by Witt and Erickson (M. Witt and R. P. Erikson, A rapid method for detection of Y-chromosomal DNA from dried blood specimens by the polymerase chain reaction. Hum. Genet., 82 (1989) 271-274)). Two different pairs of primer were used. One was X1, X2 (X1: 5'-AATCATCAAATGGAGATTTG-3'; X2: 5'-GTTCAGCTCTGTGAGTGAAA-3') to flanking the 170 bp fragment of the alphoid repeats on the human X chromosome, and the other was Y11, Y22 (Y11: 5'-ATGATAGAAACGGAAATATG-3'; Y22: 5'-AGTAGAATGCAAAGGGCTC-3') to flanking the 130 bp fragment of the alphoid repeats on the human Y chromosome. Extracted DNA solutions from mummy samples was purified using a spin column (T. Yoshii, K. Tamura, T. Taniguchi, K. Akiyama and I. Ishiyama, Water-soluble eumelanin as a PCR-inhibitor and a simple method for its removal. Jpn. J. Legal Med., 47 (1993) 323-329 (in Japanese with English abstract) for removing PCR-inhibitors, and bovine serum albumin (BSA) was employed to inhibit the remaining impurities even after the purification with the column. In six adult cases where the putative sex was determined from external morphology, the sex in five cases was consistent with that by PCR using hair, muscle, and skin samples, but the other one was inconsistent. In two adult cases where sex estimation was externally impossible, the sex was determined to be male because both X-specific and Y-specific bands were clearly detected. The child mummy was definitely male. This study shows that the sex determination was possible by the PCR method even with very ancient human samples > 1300 years old, that spin column was useful for removing impurities in the DNA solution from ancient human samples and that the BSA of optimum concentration suppressed the action of the PCR-inhibitory factors.

Adult↗

The role of self peptides in the allogeneic cross-reactivity of CTLs.

This study presents data relevant to understanding the molecular and structural basis for the cross-reactivity of many CTLs on multiple MHC targets. Five anti-H-2Kb alloreactive CTL clones derived from B6.C-H-2bm1 (bm1), B6.C-H-2bm8 (bm8), and B6.C-H-2bm11 (bm11) mice and a Sendai virus-specific H-2Kb-restricted CTL clone were studied. Self peptides extracted from Kb molecules were fractionated by HPLC and tested for their ability to be recognized on RMA/s (H-2b) cells by those clones. For each alloreactive clone, a single dominant peptide peak was found to sensitize target cells. In addition to recognizing peptides presented by the Kb molecule, the five alloreactive clones and the one Sendai virus-specific clone all showed cross-reactivities on a panel of Kbm mutant cells in a peptide-dependent manner. Two CTL clones, one alloreactive and one virus specific, cross-recognized Kbm targets by each responding to a unique self peptide in the context of the mutant MHC molecules. Our data underscore the prevalent idea that TCR-alpha beta have an inherent structural capability to react with several peptide/MHC structural patterns other than the original peptide/MHC pattern that might have been used to select that TCR. The high incidence of cross-reactivity seems to reflect a feature of the mechanism of positive selection in the thymus and the need for T cells in the repertoire to have an expanded capability for responding to a wide variety of foreign Ags.

Animals↗

Transmissible retrovirus in Epstein-Barr virus-producer B95-8 cells.

Epstein-Barr virus (EBV) released from the B95-8 marmoset cell line has served as a prototype for biologic and biochemical studies of EBV. Here we identify and characterize a retrovirus carried by many cultures of B95-8 cells. The experiments were stimulated by the isolation of a cDNA clone from B95-8 cells in which sequences from the EBV large internal repeat were linked to gag sequences similar to those of squirrel monkey retrovirus, human isolate, SMRV-H. However, among 413 amino acids predicted from the nucleotide sequence of the gag region of the B95-8 SMRV isolate there were 48 amino acid changes that distinguished this virus from SMRV-H originally isolated from a human lymphoid cell line by Oda et al. (1988, Virology 167, 468-476). Nucleic acid and antibody probes were developed for the B95-8 isolate of SMRV. Using such probes, we found that SMRV-B95-8 was readily transmissible, independent of EBV, as an infectious virus to human B and T cell lines. SMRV-B95-8 was highly fusogenic in the presence or absence of EBV. The ultrastructural appearance of the B95-8 retrovirus was characteristic of a type D retrovirus. Cells dually infected with EBV and SMRV-B95-8 did not demonstrate increased levels of lytic EB viral replication. SMRV-B95-8 did not by itself cause lymphocyte immortalization or enhance immortalization by EBV. Thus SMRV-B95-8 does not contribute to the major biologic properties of the B95-8 strain of EBV.

Amino Acid Sequence↗

Expression of a multidrug resistance gene in human rheumatoid synovium.

The objective of this study was to assess the expression of a multidrug resistance (MDR) phenotype, implicated in the cellular resistance of tumor to chemotherapy, in rheumatoid synovial membrane. Synovial membrane from 16 rheumatoid (RA) patients was studied. Six patients with osteoarthritis constituted the control group. The cell membrane expression of the glycoprotein Pgp 170, encoded by the MDR 1 gene, was determined by an immunoperoxidase technique using two different monoclonal antibodies (JSB 1, C 219). The polymerase chain reaction (PCR) methods were used in parallel to detect the presence of the MDR 1 gene mRNA in the synovial cells. Pgp 170 was expressed on the cell membrane of five RA patients and MDR 1 cellular transcription was detected in one other RA patient. We did not observe any association between synovial glycoprotein expression and age, disease activity, and a specific treatment with a long-acting drug. However, MDR protein expression was associated with the successive treatment with more than three disease-modifying antirheumatic drugs (DMARDs). We concluded that the synovial membrane expresses a glycoprotein recognized by the antibodies JSB 1 and C 219. The absence of concomitant MDR 1 transcription suggests the expression of an atypical MDR phenotype in the synovial membrane, distinct from the Pgp 170 encoded by the MDR 1 gene. The implications of the MDR phenotype and the resistance of RA to DMARDs is further discussed.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

gp120, an HIV-1 protein, increases susceptibility to hypoglycemic and ischemic brain injury in perinatal rats.

Recent data suggest that gp120, a glycoprotein secreted by HIV-1-infected macrophages, is neurotoxic, and that toxicity is mediated, at least in part, by overactivation of NMDA-type excitatory amino acid receptors. In experimental animals, considerable evidence indicates that hypoglycemic and ischemic neuronal injury are mediated by endogenous excitatory amino acids. We hypothesized that in the presence of gp120 the severity of brain injury resulting from hypoglycemia and cerebral ischemia would increase. To test this hypothesis in vivo, we evaluated the influence of gp120 on the extent of brain injury resulting from these two clinically relevant pathophysiological insults in 7-day-old (P7) rats, the developmental stage of peak susceptibility to NMDA neurotoxicity. We compared the severity of hippocampal injury resulting from right intrahippocampal injections of gp120 (50 ng) in P7 rats rendered markedly hypoglycemic (n = 10) and in controls (n = 12). We also determined the influence of gp120 administration on the severity of hypoxic-ischemic injury, using a perinatal rat stroke model. P7 rats received intrahippocampal injections of gp120 (50 ng) (n = 23) or saline (n = 18) and then underwent right carotid ligation, followed by 2 h exposure to 8% oxygen. Brain injury was evaluated 5 days later, based on neuropathology evaluation and measurements of bilateral regional cross-sectional areas. The severity of hippocampal injury, based on cross-sectional area measurements, was considerably greater in animals from the hypoglycemic group than in litter-mate gp120-injected controls. Among the animals that underwent hypoxic-ischemic lesioning, the severity of injury, based on histopathology scoring and regional volume measurements, was considerably greater in animals that received gp120 than in those that received saline. These results provide support for the hypothesis that locally secreted HIV peptides, such as gp120, may potentiate the neurotoxicity of endogenous excitatory amino acid neurotransmitters in HIV-infected brain.

Animals↗

Evidence that the antigen receptors of cytotoxic T lymphocytes interact with a common recognition pattern on the H-2Kb molecule.

Recognition of class I MHC antigens involves interaction between TCRs of cytotoxic T lymphocytes (CTL) and the two alpha helices of MHC molecules. Using a combined panel of H-2Kb mutants selected by either a CTL clone or MAbs, we have shown evidence that the TCRs of 59 Kb-specific CTL clones shared a common binding pattern on the H-2Kb molecule. Mutations of amino acid residues at the C-terminal regions, but not the N-terminal regions, of the alpha helices abrogated the recognition by the majority of the clones. The data suggests that TCRs predominantly recognize the class I MHC molecule with an orientation that is parallel to the beta-pleated strands and diagonal to the alpha helices.

Animals↗

Recognition and management of internal wound gape.

We describe a method for recognizing and managing wound gape of the internal aspect of a scleral tunnel incision. The apposition of the cataract internal incision can be adequately assessed with the use of a gonioprism during and after surgery. With self-sealing tunnel incisions, even though the external incision may be well sealed either with or without the use of a suture, the internal incision may be inconspicuously gaping. When an internal incision gapes open, it takes on the appearance of an elongated oval opening by gonioscopy, a process we have termed fishmouthing. Often fishmouthing can be closed by rapidly deepening the anterior chamber with balanced salt solution through the paracentesis incision; if this is unsuccessful, a limbal suture may be required. Assessment of the internal incision with a gonioprism and management of internal incision fishmouthing is an important method to ensure wound stability and minimize surgically induced astigmatism.

Anterior Chamber↗

[Dynamec changls in dimension of cross-sectional areas of lumbar canal and dural sac: an experimental study].

The variation in the cross-sectional areas (CSA) of lumbar canal and dural sac under extension and flexion was studied by using CT scans in ten human cadaver lumbar spine specimens. CSA at different levels or same level in varying positions were distinctive. CSA in flexion position was increased, while in extension position reduced. Dynamic changes of CSA of canal (CSAC) at L4,5,L5-S1 were very significant (P < 0.01), and those of CSA of dural a (CSADS) at all levels but L5-S1 were significant (P < 0.05). It was considered that dynamic changes of CSAC at intervertebral levels were determined by the range of lumbar motions, but those of CSADS were influenced by changes of canal and biomechanical factors of intracanal soft-tissue and changes of dural sac length. Measurement of CSADS was more significant than that of CSAC.

Adolescent↗

[Experimental study on acute hypoxia in newborn rabbits].

To investigate the hypoxic-ischemic damage of perinatal asphyxia, the acute hypoxic models of newborn rabbits were established and the effects of ligustrazine and anisodamine on pulmonary arterial pressure (PAP), dural blood flow (DBF) and blood gas of the hypoxia rabbits were observed. Acute hypoxia was caused by inhalation of 10% O2 + 90% N2 mixture. PaO2 was obviously reduced, PAP and DBF were obviously increased. But PAP in ligustrazine group did not increase and the elevated level of PAP in the anisodamine group was lower than the control. DBF and PaO2 was not affected by using both of the drugs. Ligustrazine and anisodamine might be effective for preventing and treating newborn persistent pulmonary hypertension.

Acute Disease↗

[Plasma endothelin 1 and its clinical evaluation in asthma].

Plasma endothelin 1 (ET1) was determined by radioimmunoassay in 28 cases of acute attack of asthma (attack group), 23 subjects of non-symptomatic asthma (remission group) and 20 normal volunteers (control group). The results showed that the plasma ET1 in attack group (13.4 +/- 5.2 fmol/ml) was much higher than that in both remission group (8.4 +/- 3.9 fmol/ml, P < 0.01) and control group (6.6 +/- 2.6 fmol/ml, P < 0.01). However, there was no significant difference between remission group and control group. The plasma ET1 level revealed notably negative correlation to PaO2 and FEV1% (r = -0.8257, r = -0.8157, P < 0.01). The results suggested that ET1 probably involved in pathophysiologic process of acute attack of bronchial asthma.

Adult↗

[Increased expression of platelet-derived growth factor beta receptor gene in hypoxic rat lungs].

The changes of platelet-derived growth factor (PDGF) beta receptor gene expression in hypoxic rats lungs was examined. Northern blots analysis revealed that normal lungs expression PDGF-beta receptor mRNA, with the longer of hypoxia the level of the mRNA increased rapidly. It reached a maximum at day 4, and was 1.34 fold as compared with the control (P < 0.05). Immunohistochemistry investigation showed that PDGF-beta receptor mainly distributed on smooth muscle cells and endothelial cells of middle and small arterial trees in rat lung. With hypoxia, the distribution of PDGF-beta receptors did not change, but it was more intense and reached a maximum at day 7, and was 2.40 fold as compared with the control (P < 0.05). The results suggested that increased expression of PDGF receptor gene may play a role in hypoxic pulmonary vascular remodeling.

Animals↗

[Early enteral feeding and supplement of glutamine prevent occurrence of stress ulcer following severe thermal injury].

UNLABELLED: Gastroscopic and gastric juice analysis studies were carried out on 12 patients with total body surface area over 30 percent who received early enteral feeding, supplemented with glutamine. The results indicated that early feeding was safe in major burn patients. All patients were found to have ASML on postburn days 1 to 2. Stress ulcer was not found in patients after several excision operations, and about 86 percent of ASML disappeared within about 2 weeks. CONCLUSION: early feeding and supplement of glutamine can prevent the complication of stress ulcer following severe thermal injury.

Adult↗