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Biomedical subjects

X Guo

Publications and source records attributed to X Guo.

At least 325 records · Page 18Linked to original sources
PubMed1997

Induction of endotoxin tolerance in rat bone marrow cells by in vivo infusion of tumor necrosis factor.

OBJECTIVE: To determine in a rat model whether a low-dose infusion of tumor necrosis factor (TNF) affects the production of the inflammatory cytokines TNF and interleukin (IL)-6, the immunosuppressive factor prostaglandin E2 (PGE2), and complement component C3 (C3) by isolated bone marrow-adherent and -nonadherent cells, cultured in the presence of lipopolysaccharide, a component of bacterial endotoxin. DESIGN: Randomized, controlled animal study. SETTING: Research laboratory of a university medical center. SUBJECTS: Sprague-Dawley rats (n = 18), 250 to 275 g. INTERVENTIONS: Animals received a continuous infusion of one of the following three treatments for 4 days: a) TNF in saline containing bovine serum albumin; b) saline containing bovine serum albumin; and c) saline alone. MEASUREMENTS AND MAIN RESULTS: After infusion, isolated bone marrow cells were cultured for 1 day and 3 days, with and without lipopolysaccharide (1 microgram/mL); culture supernatants were assayed for TNF, IL-6, PGE2, and C3. TNF infusion caused a decrease in the in vitro production of TNF, IL-6, and PGE2 by the lipopolysaccharide-stimulated adherent and nonadherent bone marrow cells. This tolerance to lipopolysaccharide stimulation was present after both 1 day and 3 days of culture. TNF infusion caused an increase in C3 production by the nonadherent cells. The production of TNF by adherent cells from saline-infused or bovine serum albumin-infused animals (controls) was greater in 3-day cultures compared with 1-day cultures, whereas the production of IL-6 and PGE2 was less. CONCLUSIONS: These results indicate that TNF infusion caused cells in the bone marrow to be tolerant to lipopolysaccharide stimulation or that TNF infusion programmed the cells to become tolerant to lipopolysaccharide stimulation on differentiation and/or maturation. The results also indicate that bone marrow cells may be regulated by TNF (probably indirectly) at different phases of maturation and/or differentiation with respect to the production of different mediators. Although TNF is considered to be an inflammatory cytokine, at low concentrations it may be an important down-regulator of the inflammatory response.

Animals↗
PubMed1997

Graphical representation of complex data--diurnal patterns of initiations of atrial fibrillation episodes.

A construction of a purpose designed graphical display is demonstrated in a study investigating the circadian distribution of patterns of RR interval sequences preceding episodes of paroxysmal atrial fibrillation (PAF). Based on a comparison with a (80%, 120%) range around the median of preceding 10 RR intervals, each RR interval is classified as normal, short, or long. Classifications of RR intervals in n-tuplets (n = 1, ...,5) preceding PAF episodes are used to compute probabilities of individual types of sequences occurring within 4-hour periods of the day (between 1 am, 5 am, 9 am, 1 pm, 5 pm, and 9 pm). Graphical representation of the data is proposed using a hierarchy of bar graphs. The graphical system has been filled with data of 327 atrial fibrillation episodes recorded in 46 24-hour ECGs in PAF patients. The graphical analysis supports a link between PAF initiation and cardiac autonomic status.

Anti-Arrhythmia Agents↗
PubMed1997

Sex and meiosis in autotetraploid Pacific oyster, Crassostrea gigas (Thunberg).

Sex and meiosis were studied in induced autotetraploids of the Pacific oyster (Crassostrea gigas Thunberg) and were compared with sex and meiosis in autotriploids and normal diploids. Tetraploid oysters reached sexual maturity at 1 year of age in an approximately 1:1 sex ration. In contrast with the abnormally high frequency of hermaphrodites among triploids, tetraploids had about the same level of hermaphrodites as normal diploids. Fecundity of tetraploids was comparable to that of normal diploids, differing from the greatly reduced fecundity of triploids. Homologous chromosomes synapsed predominantly as trivalents in eggs from triploids and as quadrivalents in eggs from tetraploids. After fertilization, eggs from tetraploids and triploids went through two meiotic divisions, as normal eggs did. The average gamete chromosome number was 10.0 for diploids and 19.9 for tetraploids. The distribution of gamete chromosome numbers from triploids suggested that the extra chromosome in the trivalent segregated randomly during anaphase I. In tetraploids, however, the two extra chromosomes in the quadrivalents did not segregate independently and, instead, they preferentially cosegregated to opposite poles producing balanced gametes. These results suggest that mechanisms may exist to weight, balance, and equally distribute quadrivalents, possibly through mitotic force and tension. Errors in chromosome balancing in normal meiosis may result in nondisjunction, which is the primary cause of human aneuploidy.

Animals↗
PubMed1997

Characteristics of tetrahydroprotoberberines on dopamine D1 and D2 receptors in calf striatum.

AIM: To study the characteristics of tetrahydroprotoberberines (THPB) on dopamine D1 and D2 receptors and elucidate their structure-activity relationship. METHODS: Radioligand assay in vitro with a two-site model program analysis. RESULTS: Four THPB with two hydorxyl groups on C2 and C9 or C2 and C10 exhibited RH and RL two binding sites to D1 receptors and guanosine triphosphate regulated the RH binding site of SPD and THPB-132A in competition assay, while eleven THPB including nonhydroxy-THPB, monohydroxy-THPB, and THPB with two hydroxyl groups attaching to C3 and C10 showed one binding site to D1 receptors under the same conditions. However, the tested eleven THPB all manifested one binding site to D2 receptors in competition assay, and the 2-hydroxy-THPB had the most potent affinity for D2 receptors. CONCLUSION: Dihydroxy-THPB with two hydroxyl groups attaching to C2 and C9 or C2 and C10 possess the intrinsic activity of agonist to D1 receptors, while the other THPB do not. The tested eleven THPB all are the antagonists of D2 receptors.

Animals↗
PubMed1997

Oxidized low-density lipoproteins induce apoptosis in aortic and endocardial endothelial cells.

AIM: To examine whether oxidized low-density lipoproteins (ox-LDL) might induce apoptosis in bovine aortic and endocardial endothelial cells (BAEC and BEEC). METHODS: Low-density lipoproteins (LDL) were isolated from healthy human plasma by ultracentrifugation and oxidized by CuSO4 10 mumol.L-1. BAEC and BEEC were incubated in a medium containing ox-LDL, LDL, or phosphate-buffer solution (PBS) as control. DNA fragmentation was visualized by agarose gel electrophoresis and determined quantitatively using Hoechst-33258 fluorochrome. RESULTS: Ox-LDL, not LDL, elicited typical apoptotic changes and DNA fragmentation in BAEC and BEEC. In BAEC, dextran sulfate, and cicloheximide (Cic) exhibited no effect on DNA fragmentation induced by ox-LDL. Butylated hydroxytoluene (BHT) 20 mumol.L-1 completely inhibited Cu(2+)-mediated oxidation of LDL as well as the apoptosis-inducing effect of Cu(2+)-exposed LDL. Lysophosphatidylcholine (LPC) did not elicit DNA fragmentation in BAEC and in BEEC. DNA fragmentation induced by ox-LDL in BAEC and in BEEC was blocked by chelating the calcium of the culture medium by egtazic acid. CONCLUSION: Ox-LDL induces apoptosis in BAEC and BEEC without involving the LPC.

Animals↗
PubMed1997

[Augmentation rhinoplasty with particulate hydroxy apatite artificial bone in 50 cases--a follow-up of 8 years].

To investigate the long term results of the particulate hydroxy apatite (HA) artificial bone in augmentation rhinoplasty, 50 patients were followed up for 8 years after the operation. The clinical study included the patient's self-evaluation and the surgeons' objective evaluation of the operation results, analysis of nasal radiographs for the position, shape of the HA implant and its relation with the nasal bone. The observations show that HA is stable and the long-term results of augmentation rhinoplasty with HA are very good. It is concluded that HA is a new, ideal, bioactive filling material for augmentation rhinoplasty.

Adult↗
PubMed1997

[Effects of captopril on the myocardial performances and hemodynamics after cardiac arrest].

UNLABELLED: The effects of cardioplegia and reperfusional blood containing 4.6 mumol/L captopril (CPL) on the myocardial performances and hemodynamics of canine heart under hypothermic extracorporeal circulation were studied. Twenty four mongrel dogs were divided randomly into 3 groups. CONTROL GROUP: Only modified St. Thomas cardioplegia was used. CPL group: St. Thomas cardioplegia containing CPL 4.6 mumol/L was used and the same concentration of captopril in the circulatory blood was established before releasing the cross clamp. CPL + phenylephrine group: The concentration was the same as the CPL group, with an additional dose of phenylephrine (2 micrograms/kg) into the oxygenator and abdominal coarctation. The results revealed that the coronary blood flow and left ventricular contractility and relaxation indices of CPL group were significantly improved than those of the control group, and increasing the systemic and pulmonary vascular resistence had no effect on the cardiac function protected by captopril. It is suggested that captopril could ameliorate the recovery of myocardial performences by inhibitting myocardial and systemic renin-angiotensin system and scavenging free radicals.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

[Application of rigid bronchoscopy in airway management after lobectomy of lung].

OBJECTIVE: Application of rigid bronchoscopy in airway management after lobectomy of lung was recommended, and its significance was discussed. METHODS: Bronchoscopies were performed in three patients scheduled for lobectomy of lung undergoing epidural plus general anesthesia. Each patient was examined two times. The first examination was done after anesthetic induction and intubation. The second was given at the end of operation. RESULTS: Rigid bronchoscopy under general anesthesia could clearly show the inner structures of trachea, bronchi and location of carcinoma. Under direct version, the secretion and sludged blood in the trachea and bronchi after lobectomy could be scavenged. CONCLUSION: It was suggested that with the use of bronchoscopy the complications including postoperative atelectasis and bronchial-pleural fistulization could be reduced.

Adult↗
PubMed1997

[The curative effects of anti-TNF monoclonal antibody in E. coli infected mice].

OBJECTIVE: To evaluate effects of monoclonal antibody (McAb) against TNFa on E. coli infected mice. METHODS: 30 mice (10 week old, Kunming) were divided equally into three groups. The first group, as a control, 200 microliters saline (NS)/mouse was injected intravenously; Second group (untreated group), only E. coli (10(7) organisms/200 microliters NS) were injected intra-abdominaly; Third group (treated group), E. coli (10(7) organisms) were injected intra-abdominal and McAb against TNF alpha 2 mg/kg dissolved in 200 microliters NS were injected intravenously. After 24 h, observed the survival rate, compared the serum TNF level in blood and investigated pathology of intestine, lung and liver. RESULTS: There was a higher survival rate in treated group, with the serum TNF level lowered significantly, and the untreated mice had severe pathologic changes in viscera. CONCLUSION: Using anti-TNF alpha McAb was effective in reducing mortality rate in mice after infected with E. coli, but could not prevent the pathologic changes.

Animals↗
PubMed1997

[Relationship between nasal airflow sensation and nasal patency].

The relationship between nasal airflow sensation and nasal patency was evaluated by means of visual analogue test and anterior rhinomanometry. It was demonstrated that there is no significant correlation between the subjective sensation of nasal airflow and objective assessment of nasal airflow resistance. The site responsible for sensing airflow is located in the nasal vestibule. The volatile agents used in traditional Chinese medicine for nasal obstruction, such as camphor and menthol, could only improve the nasal sensation of airflow without alteration of nasal airway resistance. Our results suggested that the nasal sensation of airflow could not reflect real patency completely. Therefore, assessment of subjective sensation of airflow and measurement of nasal airway resistance combined must be used in the diagnosis and treatment of nasally obstructed patients.

Adult↗
PubMed1997

[Effect of processing and storage time on content of hesperidin in green tangerine peel].

The contents of hesperidin in Green Tangerine Peel (Citrus reticulata), in its processed products and in commecial samples were determined by HPLC. The results indicate that the contents of hesperidin in the processed products from Chengdu and Huangyan are 14.28% and 10.75% less than shose of the crude drugs respectively. It has been found out that the content of hesperidin in Green Tangerine Peel before and after processing reduces with the passage of storage time.

Citrus↗
PubMed1997

The development of monoclonal antibody against rhTNF and its curative effects on E. coli infected mice.

Fifteen hybridoma cell lines producing monoclonal antibodies (McAb) against recombinant human tumor necrosis factor alpha (rhTNFa) have been established by fusing SP 2/0 cells with spleen cells from a BALB/c mouse immunized with rhTNFa. Following J. M. Davis's Works, semi-solid medium was used for initial cloning. Five of them were studied further. Their main chromosome numbers range were 96 to 105, all of them were IgG1 subclass. The affinities of these McAbs were estimated to be 1.25 x 10(8) mol/L, 1.12 x 10(8) mol/L, 2.34 x 10(8) mol/L, 8.55 x 10(7) mol/L, 1.04 x 10(8) mol/L, respectively. Two groups of mice challenging with E. Coli (10(7) organisms), one group treated with 2 mg/kg anti-TNF monoclonal antibody, the other did not. There was a higher survival rate in treated group, the serum TNF level was significantly lower too, and the untreated mice had severe pathologic changes in viscera.

Animals↗
PubMed1997

[Cultivated technique of high yield for Polygonatum officinale].

By studying cultivated materials, hided crops, cultivated way, applied fertilizer about the cultivation of Polygonatum officinale, put forward following the methods of cultivation of P. officinale. Choose rhizome segments with top buds as plant materials, adopt level rectangular pieces of land in a field width 100 cm, cultivate late-maturing corn as hiding shady, adopt density of 1.5-2.0 ten thousand plants/mu, apply N and P fertilizers in the growth.

Fertilizers↗
PubMed1997

[Glomeruli manifestation of hepatitis C virus infection].

The purpose of this study was to explore the relationship between hepatitis C virus (HCV) infection and glomerulonephritis. Renal autopsy tissues taken from 21 patients with HCV infection were examined by immunohistochemical technique (S-P assay) with monoclonal anti-HCV NS3 and anti-HCV NS5. Results showed that HCAg positivity were detected in 13 out of 21 renal tissues (61.9%). 11 and 1 out of 13 were identified as membranoproliferative glomerulonephritis (MPGN) and mesangial proliferative glomerulonephritis (MsPGN) respectively, and another 1 case did not show obvious lesion. 8 out of 21 cases were negative for HCAg, in which MsPGN and membranous glomerulonephritis (MN) as well as postinfectious glomerulonephritis (PSGN) were identified in 2 and each in 1 case, respectively, except another 4 cases with no obvious lesion. The renal lesion were more common and diverse in HCV associated glomerulonephritis than hepatitis B virus (HBV) associated glomerulonephritis, the show of clinical data were similar between the two. There was HCV related glomerulonephritis and the clinical manifestation may present relevantly.

Female↗
PubMed1997

[The in vitro inhibitory effect of CD8+ cells from patients with aplastic anemia on normal CFU-GM growth was blocked by cimetidine].

OBJECTIVE: To investigate the effect of histamine type II (H2) receptors on the inhibition of hematopoiesis by CD8+ cells from aplastic anemia (AA) patients. METHODS: The effects of CD8+ cells and/or cimetidine, alone or in combination, on normal human CFU-GM growth were studied by using CFU-GM assay. RESULTS: The CD8+ cells from the peripheral blood of AA patients significantly suppressed the growth of normal allogeneic CFU-GM. This inhibitory effect could be blocked by 0.5 x 10(-5) mol/L or 1.0 x 10(-5) mol/L cimetidine. 1.0 x 10(-5) mol/L cimetidine alone slightly inhibited the growth of normal CFU-GM, but 0.5 x 10(-5) mol/L cimetidine did not. CONCLUSION: H2 receptor antagonist cimetidine abolished the suppressive effect of AA patients CDB+ cells on the growth of normal CFU-GM.

Adult↗
PubMed1997

The gut as a source of inflammatory cytokines after stimulation with endotoxin.

OBJECTIVE: To find out if endotoxin (LPS) can mediate the production of inflammatory cytokines by enterocytes. DESIGN: Laboratory experiment. SETTING: Teaching hospital and burns unit, USA. MATERIAL: Caco-2 cells (HTB38, human adenocarcinoma, and colon). MAIN OUTCOME MEASURES: Concentrations of tumour necrosis factor alpha (TNF-alpha), interleukin 6 (IL-6) and prostaglandin E2 (PGE2) in cell culture supernatants. RESULTS: LPS significantly increased the production of TNF from 8.9 to 26.4 units/ml in 24 h and this increase persisted at a lower level for 4 days with an increase from 2.3 to 9 units/ml at a cell concentration of 2 x 10(5) cells/ml. There was no increase in TNF production when the cells were cultured at 5 x 10(5) cells ml with LPS. At a concentration of 2 x 10(5) cells/ml, the cells produced small amounts of IL-6 in 24 h or 4 day cultures with or without LPS. At a concentration of 5 x 10(5) cells/ml, LPS significantly increased IL-6 production in 24 h from 142 to 433 units/ml and from 106 to 250 units/ml in 4 days. The amount of IL-6 produced by LPS-stimulated cells was greater at 1 day than at 4 days. There was no significant difference in PGE2 production by the cells under any of the incubation conditions. CONCLUSION: Enterocytes can produce TNF and IL-6, and endotoxin can increase the production of these cytokines by enterocytes. The gut therefore has the potential to become an important source of inflammatory cytokines.

Caco-2 Cells↗