Bacterial endotoxin is considered as one of the critical risk factors in medical devices, especially implanted devices that directly or indirectly contact with blood circulating system. In that case, endotoxin limits for implanted medical devices is important in determine the safety of medical devices. According to GB/T 14233.2-2005, the requirements of endotoxin index for intrathoracic medical devices is 2.15 EU per device. However, the definition of "intrathoracic medical devices" is vague. Specifically, "for cardiovascular system application" instead of "intrathoracic application" is more reasonable. With the deeper understanding of the risk of endotoxin in medical devices and considering the internationally accepted standards, the limits of endotoxin in medical devices for cardiovascular system application is acceptable at 20 EU per device.
Endotoxins

OBJECTIVETo study the anti-endotoxin of different concentration baicalin.

METHODS6.250 microg/mL, 3.125 microLg/mL, 1.562 microg/mL and 0.781 microg/mL baicalin solutions were mixed with I EU/mL endotoxin, respectively. The mixtures were put into water of (37+/-1) degrees C for 15 min, 30 min and 60 min. The degrading effects were determined by using limulus amebocyte lysate test (LAL test).

RESULTS1) The degrading effect of 6.250 microg/mL, 3.125 microg/mL and 1.562 microg/mL baicalin solution on I EU/mL endotoxin was degraded completely in 15 min, 30 min and 60 min, respectively. 2)The degrading effect of 3.125 microg/mL, 1.562 microg/mL and 0.781 microg/mL baicalin solution on 1 EU/mL endotoxin after these mixtures had been incubated for 15 min. Endotoxin values were (0.155 5 +/- 0.002 8) EU/mL, (0.212 1+/-0.004 9) EU/mL, (0.355 9+/-0.013 9) EU/mL, respectively. These differences among them were statistically significant (P<0.01). 3) The degrading effect of 1.562 microg/mL and 0.781 microg/mL baicalin solution on 1 EU/mL endotoxin after these mixtures had been incubated for 30 min. Endotoxin values were (0.1640+/-0.0025) EU/mL and (0.2094+/-0.004 4) EU/mL, respectively. These differences between them were statistically significant (P<0.01).

CONCLUSIONThe action of anti-endotoxin of baicalin is dose-dependent and time-dependent. The results show that baicalin has the stronger anti-endotoxin effect.

Endotoxins ; Flavonoids ; Limulus Test

OBJECTIVETo observe the binding power of polymyxin B (PMB) and its simulation peptide to lipopolysaccharide (LPS) and lipoid A.

METHODSLPS and lipoid A were separately coated on biosensor. 5 microl of PMB (0.01 microg/L) 5 microl of its simulating peptide 1 (PMBSP1 0.01 microg/L) and 5 microl of its simulating peptide 2 (PMBSP2, 0.01 microg/L) were respectively added into the hydrophobic sample pool. The combining power of PMB and its simulating peptides PMBSP1 and PMBSP2 to LPS and lipoid A was compared. RESULTS (1) PMBSP1 almost did not bind LPS and lipoid A, while PMB and PMBSP2 possessed high affinity with LPS and lipoid A. (2) The peak value (98.41 +/- 7.31) rad/s of PMBSP2 binding LPS was much higher than that (83.58 +/- 5.42) rad/s of PMB in binding LPS (P < 0.05). While the peak value of PMB in binding lipoid A was similar to that of PMBSP2. (3) The peak value of PMB binding LPS was significantly lower than that of PMB in binding lipoid A (P < 0.05). But there was no difference between the peak value of PMBSP2 in binding LPS and that of PMBSP2 in binding lipoid A. (4) PMBSP2 could bind to LPS and lipoid A in a shorter time to reach peak levels.

CONCLUSIONCompared with PMB, the PMBSP2 could bind to LPS and lipoid A in a shorter time. In addition, PMBSP2 exhibited similar affinity to LPS and lipoid A. This indicated that PMBSP might possess better anti-LPS activity due to its lack of space steric hindrance when PMBSP binding the lipoid A of LPS.

Cell Wall ; chemistry ; Endotoxins ; Gram-Negative Bacteria ; Lipopolysaccharides ; chemistry ; toxicity ; Peptides ; chemistry ; pharmacology ; Polymyxin B ; chemistry ; pharmacology

Ovarian cancer (OC), the deadliest gynecological cancer, results in poor overall survival, urgently requiring a novel therapeutic approach. As cumulative exposures to endotoxins decreased OC risk epidemiologically, we evaluated if LPS, a Toll-like receptor 4 agonist known as active component of endotoxins, could increase survival in the murine peritoneal dissemination model of SKOV-3 OC cells. LPS significantly increased the mean survival time of more than 116 days compared with 63 days in the control. Furthermore, no tumor burden was present in three mice among eight LPS-treated mice. SKOV-3 cells were not responsive to LPS and showed unaltered chemokine signature. Rather than direct effects to OC cells, LPS was found to increase proinflammatory chemokines and cytokines, such as CXCL1, CXCL8, TNF, and IL-1B, in innate immune system. Taken together, LPS is likely to potentiate the cytotoxic-related innate immunogenicity via proinflammatory chemokines and cytokines, which attenuates the peritoneal dissemination of OC.
Animals ; Chemokines ; Cytokines ; Endotoxins ; Immune System ; Immunity, Innate ; Lipopolysaccharides ; Mice ; Ovarian Neoplasms ; Survival Rate ; Toll-Like Receptor 4 ; Tumor Burden

OBJECTIVETo explore the application of biosensor technology in the determination of endotoxin-neutralizing materials.

METHODSAfter mixing polymyxin B (PMB) with endotoxin in certain concentration, the neutralizing ratio of PMB to endotoxin was assessed by biosensor technique and limulus amebocyte lysate test respectively. The results from the two methods were compared.

RESULTSThe neutralizing ratio of PMB to endotoxin as assessed by biosensor technology was 0.35 microg to 1 ng, while that by dynamic turbidimetric and chromogenic limulus amebocyte lysate (LAL) technique was 0.5 mg to 1 ng and 1 mg to 1 ng, respectively. The results obtained by biotechnology were similar to that by biosensor technique.

CONCLUSIONBiosensor technology was an accurate, convenient and rapid method for the determination of potency of endotoxin-neutralizing materials.

Bacterial Proteins ; analysis ; Biosensing Techniques ; methods ; Endotoxins ; analysis ; Lipid A ; analysis ; Polymyxin B ; analysis ; Reproducibility of Results ; Sensitivity and Specificity

INTRODUCTIONThis study investigated the responses of plasma endotoxin and pro- and antiinflammatory cytokines during a 21-km road race in warm and humid conditions. The influence of carbohydrate-electrolyte (CE)-water (WA) drink mix ingested on leukocyte subset responses and the association between plasma lipopolysaccharide (LPS) concentration and fluid balance, exercise intensity, and body core temperature (Tc) were also studied.

MATERIALS AND METHODSThirty runners provided blood samples before and after the half-marathon for leukocyte, LPS and cytokine analyses. Tc was measured by the ingestible telemetric temperature sensor and fluid intake and split-times were recorded at 3 km intervals. Exercise intensity was determined by matching running speed and heart rate during the race with the corresponding speed-oxygen uptake relationship and heart rate measured in the laboratory 2 to 6 weeks before the race.

RESULTSPlasma LPS concentration increased from 1.9 +/- 1.9 pg/mL before, to 2.5 +/- 1.9 pg/mL after running (P <0.05). Peak plasma LPS concentration was 7.5 pg/mL. Plasma IL-1beta and TNF-concentration did not change significantly, whereas significant increases in IL-10 (50%), IL-1ra (23.2%) and IL-6 (65.2%) were observed after the race. No significant correlation between plasma LPS concentration and exercise intensity, hydration and Tc was observed.

CONCLUSIONLeukocyte subset responses were not related to the ratio of CE and water drink mix ingested. Running a half-marathon can induce mild endotoxaemia, which is not related to exercise intensity, fluid balance, and Tc responses. Mixing CE drink with water did not mitigate postexercise leukocytosis and lymphopenia.

Adult ; Beverages ; Cytokines ; immunology ; Endotoxins ; blood ; immunology ; Fluid Therapy ; Hot Temperature ; Humans ; Humidity ; Leukocytes ; immunology ; Lipopolysaccharides ; immunology ; Male ; Physical Exertion ; physiology ; Running ; physiology

OBJECTIVETo investigate the lipopolysaccharide (LPS) antagonizing biological activity of densefruit pattany root-bark extract (DPR-2) in vitro.

METHODSThe effect of DPR-2 in neutralizing LPS (0.1 microg/L) was detected by kinetic turbidimetric limulus test. The effect of different concentrations of DPR-2 (0,8.0,16.0,32.0,64.0 mg/L) on binding of FITC-conjugated LPS (FITC-LPS,100.0 microg/L) to murine RAW264.7 cells was analyzed with laser scanning confocal microscopy. The expression of TNF-alpha and IL-6 mRNA in RAW264.7 cells after exposure to LPS (100.0 microg/L) were determined by real-time RT-PCR.

RESULTSDPR-2 could neutralize LPS (P < 0.05 or P < 0.01), and inhibit the binding of FITC-LPS to RAW264.7 cells in a dose-dependent manner when the concentration of DPR-2 was above 16.0 mg/L. Furthermore, DPR-2 could markedly inhibit the expression of TNF-alpha and IL-6 mRNA in LPS-stimulated murine RAW264.7 cells.

CONCLUSIONDPR-2 exhibit an anti-LPS effect in vitro, which may be related to its capacity to neutralize LPS and inhibit binding of LPS for its receptors.

Animals ; Cell Line ; Drugs, Chinese Herbal ; pharmacology ; Endotoxins ; antagonists & inhibitors ; In Vitro Techniques ; Limulus Test ; Lipopolysaccharides ; antagonists & inhibitors ; Mice ; Monocytes ; drug effects ; metabolism ; Plant Extracts ; pharmacology

OBJECTIVETo investigate the effects of different concentrations of lipopolysaccharide (LPS) on proliferation and apoptosis of human umbilical cord mesenchymal stem cells (hUCMSCs) in vitro, and to explore their possible mechanism.

METHODShUCMSCs from umbilical cord tissue of full-term healthy fetus delivered by caesarean section were isolated and cultured in vitro using tissue attachment method. The 3rd passage hUCMSCs were used in the study. Cells were divided into groups A, B, C, D, and E, which were treated with DMEM/F12 medium containing 0, 0.1, 1.0, 10.0, and 100.0 µg/mL of LPS respectively. In groups B, C, D, and E, methyl-thiazole-tetrazolium assay was used to detect proliferative activity of hUCMSCs at post treatment hour (PTH) 12, 24, and 48 (denoted as absorption value), with 5 samples in each group at each time point; apoptosis of hUCMSCs at PBH 24 was identified with acridine orange-ethidium bromide (AO-EB) staining, with 4 samples in each group; apoptotic rate of hUCMSCs was determined by flow cytometer, with 5 samples in each group. Above-mentioned indexes were determined in group A at the same time points. Data were processed with analysis of variance and LSD- t test.

RESULTS(1) There was no statistically significant difference in proliferative activity of hUCMSCs at PTH 12 among groups A, B, C, D, and E (with t values from -1.67 to 1.33, P values above 0.05). Compared with that of group A, proliferative activity of hUCMSCs was increased in groups B, C, and D at PTH 24 and 48 (with t values from -13.42 to 17.34, P < 0.05 or P < 0.01), especially so in group C. Proliferative activity of hUCMSCs was lower in group E at PTH 24 and 48 than in group A (with t values respectively 8.64 and 17.34, P values below 0.01). (2) Obvious apoptosis of hUCMSCs was observed in group E but not in the other 4 groups with AO-EB staining. (3) Apoptosis rates of hUCMSCs in groups A, B, C, D, and E were respectively (3.1 ± 0.6)%, (2.6 ± 0.7)%, (2.9 ± 0.8)%, (3.1 ± 0.4)%, (25.1 ± 2.7)% (F = 272.19, P < 0.01). Apoptotic rate of hUCMSCs in group B, C, or D was respectively close to that in group A (with t values respectively 1.22, 0.57, -0.14, P values above 0.05), but it was higher in group E than in group A (t = -17.63, P < 0.01).

CONCLUSIONShUCMSCs proliferation may be promoted by low concentration of LPS. hUCMSCs proliferation is inhibited or induced to apoptosis along with the increase in concentration of LPS, and it may be related to activation of different major molecular signaling pathways by different concentrations of LPS.

Apoptosis ; drug effects ; Cell Proliferation ; Endotoxins ; adverse effects ; Humans ; Lipopolysaccharides ; pharmacology ; Membrane Proteins ; Mesenchymal Stromal Cells ; cytology ; drug effects ; Signal Transduction ; Umbilical Cord ; cytology

OBJECTIVETo explore the mechanism of endotoxin tolerance (ET) through observing the expression of interleukin 1 receptor associated kinase-4 (IRAK-4) during endotoxin tolerance development in Kupffer cells (KCs).

METHODSIsolated KCs of Balb/c mouse were divided into two groups: the non-endotoxin tolerance (NET) group and the endotoxin tolerance (ET) group, which were pretreated with 10 ng/ml lipopolysaccharide (LPS) for 24 h. Then, the two groups were treated with 100 ng/ml LPS. The expressions of IRAK-4 gene and protein level were determined by RT-PCR and Western blot. The activities of NF-kappaB of KCs and the TNFalpha level were estimated by ELISA at 0 h, 1 h, 3 h, 6 h and 12 h after LPS stimulation.

RESULTSThe ultimate level of IRAK-4, the activities of NF-kappaB and the TNFalpha level were evidently lower in the ET group than those in the NET group (t = 12.4, 17.4 and 138.9 respectively, P<0.01).

CONCLUSIONSPretreatment with LPS on KCs could induce endotoxin tolerance of KCs and inhibition of IRAK-4 expression may be one of the reasons for its development.

Animals ; Cells, Cultured ; Endotoxins ; immunology ; Immune Tolerance ; Interleukin-1 Receptor-Associated Kinases ; biosynthesis ; genetics ; Kupffer Cells ; cytology ; immunology ; metabolism ; Lipopolysaccharides ; immunology ; Male ; Mice ; Mice, Inbred BALB C

OBJECTIVETo investigate the enhancing effect of Chinese medicine-Xuebijing injection on lipopolysaccharide (LPS) -induced apoptosis of CD4+ CD25+ regulatory T cells (Tregs) and polarization of helper T cells (Th).

METHODSCD4+ CD25+ Tregs collected from rat spleen in vitro by immunomagnetic beads assay were divided into the control group, anti-CD3/CD28 group, anti-CD3/CD28 + LPS group, anti-CD3/CD28 + "Xuebijing injection" group and anti-CD3/CD28 + LPS + "Xuebijing injection" group. Tregs apoptosis rate and expression of winged helix transcription factor (Foxp3) in Tregs were detected by flow cytometry on 3rd post culture day. CD4+ CD25- T cells were co-cultured with CD4+ CD25- Tregs (1:1) for 68 hours with canavalin A stimulation. Interferon gamma (gamma-IFN), interleukin (IL)-4 and IL-17 in supernatants, which respectively was secreted by Th1, Th2 and Th17, were measured by ELISA.

RESULTSTregs apoptosis rate of anti-CD3/CD28 + LPS + "Xuebijing injection" group (45.1 +/- 2.7%) was significantly higher than that of anti-CD3/CD28 + LPS group (29.4 +/- 1.6%, P < 0.01). Meanwhile, Foxp3 expressions in Tregs in above 2 groups were 95 +/- 9 and 140 +/- 18 respectively, showing statistically significant difference between them (P < 0.01). Gamma-IFN levels secreted in anti-CD3/CD28 + LPS + "Xuebijing injection" group were significantly higher than those in anti-CD3/CD28 + LPS group (P < 0.01), while IL-4 levels had an opposite tendency compared with gamma-IFN (P < 0.05), resulting in a marked increase in the ra- tio of gamma-IFN/IL-4 in anti-CD3/CD28 + LPS + "Xuebijing injection" group (P < 0.01). In anti-CD3/ CD28 + "Xuebijing injection" group, IL-17 secretion levels were significantly decreased compared with anti-CD3/CD28 group (P < 0.05).

CONCLUSIONSActivation of CD4+ CD25+ Tregs induced by LPS may mediate Th1 shift to Th2 response. "Xuebijing injection" can effectively regulate immune function of T cells, increase the LPS-induced apoptosis of CD4+ CD25+ Tregs as well as enhance the polarization of Th2 to Th1, thereby abating the suppressive state of cell-mediated immunity.

Animals ; Apoptosis ; Drugs, Chinese Herbal ; pharmacology ; Endotoxins ; Lipopolysaccharides ; Male ; Rats ; Rats, Wistar ; T-Lymphocytes, Helper-Inducer ; drug effects ; immunology ; T-Lymphocytes, Regulatory ; drug effects ; immunology