Search PubMed⌕ Search

Biomedical subjects

B Sun

Publications and source records attributed to B Sun.

At least 199 records · Page 11Linked to original sources
PubMed1997

[An analysis of the cause of misdiagnosis with ocular opportunistic infection].

OBJECTIVE: To evaluate the causes of misdiagnosis with ocular opportunistic infection. METHOD: The causes of misdiagnosis on 4 cases (6 eyes) with ocular opportunistic infection were analyzed. RESULTS: Acanthoamoeba keratitis was misdiagnosed as herpes simplex keratitis and fungal keratitis in 1 case (1 eye). Propionibacterium acne endophthalmitis was misdiagnosed as exogenous fungal keratitis in 1 case (1 eye). Endogenous fungal endophthalmitis was misdiagnosed as metastatic choroid cancer from lung in 1 case (2 eyes). Cytomegalovirus retinitis was misdiagnosed as endogenous fungal endophthalmitis in 1 case (2 eyes). CONCLUSION: If common therapies are of no effect with some ocular infections and the causative organisms responsible for the infection could not be found out after repeated tests, the rare ocular opportunistic infection should be considered. Special examinations (such as acanthoamoeba culture, anaerobic culture, fungus blood culture, cytomegalovirus serological assays, etc.) should be made for a definite diagnosis.

Acanthamoeba Keratitis↗
PubMed1997

[Contrast sensitivity of several blindness-inducing eye diseases and the influence of tinted filter lens].

OBJECTIVES: To evaluate the effects of tinted filter lens on the visual rehabilitation of blind and low vision patients induced by optic nerve atrophy, glaucoma and retinitis pigmentosa. METHODS: The contrast sensitivity of 22 cases with optic nerve atrophy (34 eyes), 17 glaucoma (30 eyes), 18 retinitis pigmentosa (30 eyes) and 30 normal people (60 eyes) with and without yellow and red filter lens was tested. RESULTS: The results demonstrated that a yellow filter lens could improve the optic nerve atrophy patient's contrast sensitivity at 1.5, 3, 6 and 12 c/deg, while a red filter lens could increase the contrast sensitivity at limited spatial frequencies, but it could also decrease the contrast sensitivity at some other spatial frequencies. CONCLUSION: Yellow filter lens could be applied as a non-optical visual aid in the visual rehabilitation of the blind and low vision patients induced by these three diseases, as the above results show contrast sensitivity improvement in the low spatial frequency and the peak of the contrast sensitivity curves.

Adolescent↗
PubMed1997

[The relation between trace element selenium and osseointegration of titanium implants].

Titanium implants were placed bilaterally in the proximal tibia of thirty-six adult male rabbits to demonstrate the relation between trace element selenium and titanium implants osseointegration. The animals were randomly divided into the control group and the selenium adding group. There were eighteen animals in each group. In experimental group, Na2SeO3 10 micrograms/kg body weight was given intramuscularly everyday for 6 days postoperatively, Measurement of trace element selenium contents, histologic findings and mechanical testing were applied to evaluate the effect. The results showed that trace element selenium contents of bones around implants were positively related to the strength of the implant fixation. Selenium could obviously speed up the formation of implant osseointegration and significantly improve the strength of the implants fixation compared with the control group at 1 week and 4 weeks after implantation.

Animals↗
PubMed1997

[Study on immunological pharmacology of keyin granule].

By intragastric keyin granule at the dosage of 1.0-4.0 g/kg.d[-1] for 7-10 days in mice, this drug can enhance the phagocytic function of the macrophages of peritoneal cavity, increase the index of spleen and the clearance rate of i.v. charcoal particles, obviously inhibit the formation of mouse-specific antibody and the delayed cutaneous hypersensitivity (DCH), recover the decrease of ANAE lymphocyte in periphery blood induced by cyclophosphamide. It can also improve the index of immunological organ of immunosuppression mice. These show the immunological regulative function of this drug.

Adjuvants, Immunologic↗
PubMed1997

[Fluorescence studies on the mixed solid complexes of europium-terbium-1, 10-phenanthroline-phthalate systems].

The 1, 10-phenanthroline-phthalate complexes of europium and terbium have been synthesized. Two series of mixed complexes, mechanical ground complexes (series 1) and chemical synthesized with mixed EuCl3 and TbCl3 solutions (series 2), have been also prepared. Fluorescence studies on all of the samples were performed. The results of their fluorescence spectra excited by 365nm UV-light showed that there are interactions between europium ions and terbium ions in these two kinds of mixed complexes. Their fluorescence intensities strongly changed especially for chemical synthesized mixed complexes, in which the fluorescence intensities of europium ions were greatly sensitized by terbium ions and those of terbium ions were strongly quenched by europium ions. But the peak positions of their emission bands did not shift obviously. The structure of these complexes have been characterized by FT-IR spectra. The results suggested that no free COOH groups exist and all of the nitrogen atoms of 1, 10-phenanthroline molecules coordinate to rare earth ions in all of these complexes.

English Abstract↗
PubMed1997

[Fluorescence and FT-IR spectroscopic studies on the mixed solid complexes of europium and terbium phthalate].

In this investigation, the fluorescence and FT-IR spectroscopic studies on synthesized Eu-Tb phthalate complexes and mixed solid complexes of europium and terbium phthalates were perfomed. The experimental results of the emission spectra excited by 365nm UV-light showed that the emission peak positions of Eu ( III ) [or Tb ( III )] wer shifted slightly due to the interaction between Tb ( III )and Eu ( III ) ions. However, the fluorescence intensities of one rare eath ion Eu ( III ) [or Tb (III )] were strongly influenced by the other. FT-IR spectra indicated that the coordination structures of carboxyl groups, both in mechanically mixed and synthesized solid complexes, were also changed. These results suggested that there are interactions between Eu ( III ) and Tb ( III ) ions in their mixed complexes.

English Abstract↗
PubMed1997

[Far FT-IR spectra of gallium hexafluoride ions].

Far FT-IR spectra of Rb3GaF6, alpha-Cs3GaF6 and high temperature form Cs3GaF6 and their XDS have been studied in this paper. The results indicated that Rb3GaF6 and high temperature form Cs3GaF6 are tetragonal, a = 0.632,c = 0. 886nm and a = 0.687,c = 0. 987nm respectively. alpha-Cs3GaF6 is orthorhombic, a = 1. 062,b = 0. 996,c = 0. 561nm

English Abstract↗
PubMed1997

[The relation between expression of PML-RAR alpha gene and effects of ATRA on proliferation and differentiation of NB4 cells].

OBJECTIVE: To study the relation between the PML-RAR alpha gene and the effects of ATRA on proliferation and differentiation in acute promyelocytic leukemia cell line NB4 cells. METHODS: ASODN-mediated inactivation of the PML-RAR alpha mRNA was measured by RT-PCR. The proliferation and differentiation of NB4 cells were determined by proliferation curve, morphology, CD antigen of membrane and NBT test. NB4 Cell cycle was analyzed by FACS. RESULTS: The inactivation of PML-RAR alpha mRNA by ASODN could egnhance the maturation effects and growth suppression of ATRA on NB4 cells. The percentage of S phase cell was decreased from 52% to 29%, and NBT rate increased. All suggest that the sensitivity of NB4 cell to ATRA was improved. CONCLUSION: The PML-RAR alpha gene, as a molecular marker of APL, is responsible for pathogenesis of APL, and it also decreases the sensitivity of ATRA to APL cells.

Antineoplastic Agents↗
PubMed1997

[Effect of glucocorticoid on CD4 T-lymphocyte and eosinophil activation in asthmatics].

To study the influence of oral glucocorticoid on CD4 T-lymphocyte and eosinophil activation in the asthmatics, we collected the serum samples from 14 patients who required oarl glucocorticoid therapy for moderate to severe disease exacerbations and measured the serum interleukin (IL)-5, eosinophil cationic protein (ECP) levels before and after one week with prednisone (20 mg/d) by enzyme-linked immunosorbent assay. The results revealed that after oral prednisone therapy, the serum IL-5, ECP levels and the numbers of peripheral blood eosinophils decreased, whereas the lung function significantly improved. It is suggested that glucocorticoids might exert antiasthma effect of by inhibiting CD4 T-lymphocyte activation and cytokine (e.g., IL-5) secretion.

Adolescent↗
PubMed1997

[Microsurgical restoration of foot tissue defects].

From 1984 to 1994, 236 different types of traumatic defects of foot were repaired by microsurgical tissue grafting. They included simple cutaneous flap in 187 and composite flap in 49. Among the 236 different tissue flaps, vascularized flap was used in 97 and pedicled flap in 139. The 4 fore-foot and 6 heel defects were repaired by composite skeleted cutaneous grafts with scapula and vascularized febula respectively. After the follow-up from 1 to 10 years, all the grafted tissues were survived and healed well. The functions were satisfactory, and 186 patients had resumed their original works. The key to good function following repair was to maintaion the integrity of foot structures and the sensation of the sole and heel.

Adolescent↗
PubMed1996

Genetic susceptibility to experimental autoimmune uveoretinitis in the rat is associated with an elevated Th1 response.

This study examines whether genetic susceptibility vs genetic resistance to experimental autoimmune uveoretinitis (EAU) are connected to a predisposition to mount a Th1-dominated (IFN-gamma high, IL-4 low) vs a Th2-dominated (IL-4 high, lFN-gamma low) response. Lewis rats developed disease with high incidence after immunization with the uveitogenic peptide R16, whereas F344 rats were resistant. Primed lymph node cells from both strains proliferated in culture in response to R16. However, while the Lewis cultures transferred EAU to syngeneic recipients, those of F344 did not. The Lewis cultures produced substantially more IFN-gamma mRNA and protein in response to R16, than did those of F344. Both strains made low levels of IL-10 mRNA and IL-4 mRNA. Unlike the primary cultures, long-term (R16-specific) T cell lines derived from each of the strains transferred EAU equally well to their respective recipients, and produced similar, high levels of IFN-gamma mRNA and protein. Treatment of F344 with Bordetella pertussis toxin concurrently with immunization abrogated its resistance, enhanced Ag-specific IFN-gamma production in culture, and yielded a primed cell population capable of transferring EAU. Conversely, immunization of Lewis rats with R16 in IFA induced little or no disease; the primed cells produced minimal amounts of IFN-gamma and did not transfer EAU. However, addition of IL-12 into the culture resulted in a highly pathogenic, IFN-gamma-producing cell population. We conclude that genetic susceptibility to ocular autoimmunity in this model is connected to an elevated Th1 response. Genetic resistance, however, does not seem to involve an elevated Th2 response, but rather an inhibited development of Th1-like effector cells.

Amino Acid Sequence↗
PubMed1996

A simplified, competitive RT-PCR method for measuring rat IFN-gamma mRNA expression.

We describe an adaptation of competitive RT-PCR to quantitate rat IFN-gamma mRNA expression. An IFN-gamma DNA mimic that shared the same primers and had an identical sequence to the target mRNA except for deletion of 66 nucleotides was created by a simple PCR amplification from target cDNA. To reduce variations of initial RNA concentrations, beta-actin cDNAs from each target RNA sample were normalized using the densitometric data. A known amount of pretitrated DNA competitor was then used to analyze the relative levels of target cDNA in different samples by PCR co-amplification. The amplification efficiency for both target and competitor remained constant throughout the PCR reaction, and the ratio of target to competitor PCR product remained proportional to the initial ratio of target to competitor. Relative mRNA levels among samples determined by this method were comparable to levels determined by northern blot analysis. They were also comparable to levels of IFN-gamma protein estimated by ELISA. We conclude that this method can be used to estimate the relative abundance of the target mRNA. This method is adaptable to quantitation of other cytokines and is particularly valuable if there are numerous samples or if the amount of initial mRNA is limited.

Animals↗
PubMed1996

Transactivation of the GATA-1 promoter by a myb-ets-containing mouse retrovirus is mediated by CACCC elements.

The myb-ets-containing ME26 virus causes erythroleukemia in mice by a novel mechanism involving the inappropriate activation of erythroid-specific genes in hematopoietic precursor cells. We have previously shown that the ME26 viral protein can transactivate the GATA-1 promoter in transient transactivation assays carried out in mouse fibroblasts. The mouse GATA-1 promoter, whose activity is regulated by the GATA-1 protein itself, contains a double GATA consensus sequence at its 5' end and two CACCC elements at its 3' end, both of which are crucial for promoter activity in erythroid cells, as well as a nonconsensus GATA sequence and several putative c-myb and c-ets binding sites. In order to determine which sequences in the GATA-1 promoter are crucial for activation by the ME26 viral protein, we made deletions of the promoter, cloned them into a luciferase expression vector and tested their activity in mouse fibroblasts, which do not express GATA-1. Our results indicate that sequences in the 3' end of the GATA-1 promoter, which include two CACCC elements, are essential for transactivation by ME26 virus, while other upstream sites contribute to full activation by the virus. Mutation of the CACCC sites abolishes ME26 viral transactivation. The interaction of cell extracts containing ME26 viral protein and the GATA-1 promoter fragment containing the two CACCC elements was examined by electrophoretic mobility shift analysis (EMSA) and the results showed no direct interaction between the two. However, we could detect the ubiquitous transcription factor Sp1 bound to this sequence. These data demonstrate that the CACCC element is necessary for GATA-1 promoter transactivation by ME26 virus and that the viral protein may indirectly transactivate the promoter by binding to Sp1.

3T3 Cells↗
PubMed1996

Novel chloride-dependent acid loader in the guinea-pig ventricular myocyte: part of a dual acid-loading mechanism.

1. The fall of intracellular pH (pH1) following the reduction of extracellular pH (pH0) was investigated in guinea-pig isolated ventricular myocytes using intracellular fluorescence measurements of carboxy-SNARF-1 (to monitor pH1). Cell superfusates were buffered either with a 5% CO2-HCO3- system or were nominally CO2-HCO3-free. 2. Reduction of pH0 from 7.4 to 6.4 reversibly reduced pH1 by about 0.4 pH units, independent of the buffer system used. 3. In HCO3(-)-free conditions, acid loading in low pH0 was not dependent on Na(+)-H+ exchange or on the presence of Na+. It was unaffected by high-K+ solution, by voltage-clamp depolarization, by various divalent cations (Zn2+, Cd2+, Ni2+ and Ba2+) and by the organic Ca2+ channel blocker diltiazem, thus ruling out proton influx through H(+)-or Ca(2+)-conductance channels or influx via a K(+)-H+ exchanger. The fall also persisted in the presence of glycolytic inhibitors, or the lactate transport inhibitor, alpha-cyano-4-hydroxy cinnamate. 4. In HCO3(-)-free conditions, acid loading in low pH0 was reversibly inhibited (by up to 85%) by Cl(-)0 removal and was slowed by the stilbene drug DBDS (dibenzamidostilbene disulphonic acid). In contrast, the Cl(-)-HCO3-exchange inhibitor DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulphonic acid) had no inhibitory effect. Acid loading is therefore mediated by a novel Cl(-)-dependent, acid influx pathway. 5. After switching to CO2-HCO3(-)-buffered conditions, acid loading was doubled. It was still not inhibited by Na(+)-free or high-K+ solutions but was once again inhibited (by 78%) in Cl(-)-free solution. The HCO3(-)-stimulated fraction of acid loading was inhibited by DIDS. 6. We propose a model of acid loading in the cardiomyocyte which consists of two parallel carriers. One is Cl(-)-HCO3-exchange, while we suggest the other to be a novel Cl(-)-OH-exchanger (although we do not rule out the alternative configuration of H(+)-Cl-co-influx). The proposed dual acid-loading mechanism accounts for most of the sensitivity of pH1 to a fall of pH0.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1996

Independent regulation of matrix metalloproteinases and plasminogen activators in human fibrosarcoma cells.

Serine proteases and matrix metalloproteinases have been shown to often cooperate in multiple physiological and pathological processes associated with changes in the extracellular matrix (ECM). We have examined the interaction between the plasminogen activator (PA)-plasmin system and matrix metalloproteinases (MMPs) in HT1080 human fibrosarcoma cells treated with 12-O-tetradecanoyl-phorbol-13-acetate (TPA). While TPA treatment evoked a temporary increased expression of urokinase type PA (uPA), the production of both types of human plasminogen activator inhibitors (PAI) was induced and sustained over 12 h by TPA treatment shifting the protease-protease inhibitors balance in favor of the inhibitors. TPA treatment of HT1080 cells induced the expression of interstitial collagenase (MMP-1) and increased the expression of gelatinase B (MMP-9), tissue inhibitor of metalloproteinases-1 (TIMP-1), and MT-MMP, a membrane-bound activator of progelatinase A (proMMP-2), while MMP-2 and TIMP-2 expression were decreased. Increased MT-MMP expression by TPA treatment was associated with increased activation of proMMP-2. These data show that the regulation of PA-plasmin and metalloproteinase and their specific inhibitors is uncoordinated. In addition, inhibition of the PA-plasmin system by PAI-2 or aprotinin did not prevent the activation of proMMP-2 by TPA, suggesting that plasmin is not involved in MT-MMP-mediated activation of proMMP-2.

Aprotinin↗
PubMed1996

Suppressive effect of transforming growth factor beta1 on the recurrence of experimental melanin protein-induced uveitis: upregulation of ocular interleukin-10.

Uveitis is induced in Lewis rats by immunization with bovine melanin protein (BMP) derived from the uvea and retinal pigment epithelium. Recurrence of this experimental melanin protein-induced uveitis (EMIU) develops after footpad injection of a minimal amount of Salmonella typhimurium endotoxin (LPS) following the remission of EMIU. To investigate the effect of transforming growth factor beta1 (TGFbeta1) on the recurrence of EMIU, 5 micrograms LPS booster was given to Lewis rats by footpad injection on Day 45 after BMP immunization. Daily TGFbeta1 or phosphate-buffered saline was administered either from Day 0 to 7 (group 1) or from Day 7 to 13 (group 2) after LPS booster. Delayed-type hypersensitivity (DTH) ear test was conducted on Day 12 after LPS booster and eye and blood were collected on Day 14. The incidence and severity of recurrent uveitis markedly decreased in both groups of TGFbeta1-treated rats. A lower level of serum BMP antibody was also observed by agglutination in these groups. There was no statistical difference in DTH responses between the treated and control groups. Ocular cytokine mRNA of group 1 and controls was analyzed by RT-PCR. Interleukin (IL)-2 and interferon-gamma were not detectable. IL-4 was identified at a similar level in both groups. A higher level of IL-10 was observed in group 1 rats. We conclude that TGFbeta1 suppresses recurrent EMIU, probably through upregulation of IL-10.

Animals↗
PubMed1996

Differential induction of isozymes of drug-metabolizing enzymes by butylated hydroxytoluene in mice and Chinese hamsters.

Induction of isozymes of drug-metabolizing enzymes by butylated hydroxytoluene (BHT) was studied in the male ddY mouse and Chinese hamster. In mice given 0.05 and 0.15% BHT in the diet for 14 days cytochrome P-450 contents and the activities of uridine diphosphate-glucuronyl transferase (UDP-GT) and pentoxyresorufin O-dealkylase were markedly increased, while in those fed 0.15% BHT testosterone 6 alpha-, 16 alpha- and 16 beta-hydroxylases were greatly increased, which indicated induction of cytochrome P-450 isozymes of the CYP2B family. Western blot analysis also showed an increased level of the isozyme immunorelated to rat CYP2B2 by BHT feeding. The activities of aryl hydrocarbon hydroxylase, ethoxycoumarin O-deethylase (ECOD), erythromycin N-demethylase and glutathione S-transferase (GST) remained unchanged. In Chinese hamsters given 0.05 and 0.15% BHT in the diet for 14 days activities of ECOD and GST were induced, but cytochrome P-450 contents and the activities of other enzymes were unaffected. Testosterone 15 alpha-hydroxylase was induced in hamsters fed 0.15% BHT. These findings suggested that BHT administration in the hamster induced CYP2A2-type isozyme, which was confirmed by Western blot analysis. BHT treatment enhanced activation of benzo[a] pyrene (B[a]P) as determined by the mutagenicity test, especially in Chinese hamsters. The results suggest that BHT treatment induces specific isozymes of drug-metabolizing enzymes and might modify the expression of toxicities of other chemicals.

7-Alkoxycoumarin O-Dealkylase↗