Novel conjugated microporous polymers for efficient tetracycline adsorption: insights from theoretical investigations.

This paper presents a detailed theoretical understanding of the noncovalent interactions between antibiotics tetracycline and conjugated microporous polymer (CMP), which is important to understand the recent experimental finding of efficient removal of antibiotics by CMP materials. We show that the co-work of π-π and H-π interactions determines the final equilibrium structures, when a tetracycline molecule spontaneously adsorbs to the surface or within the pores of the CMP network at physisorption distances. The binding energies for tetracycline/CMP systems are calculated to be -0.31 âˆ¼ -1.15 eV, demonstrating the reliability of the adsorption. The electronic structures of CMP nanostructures remain basically undamaged upon the tetracycline adsorption. The replacement of benzothiadiazole unit with S and N heteroatoms to the phenyl moiety in the linker effectively enhanced the molecular polarity of CMP molecule and increases the interaction area between tetracycline and CMP network, consequently enhancing the average binding energies notably. Our calculations provide useful theoretical guidance for design of novel carbon-based porous adsorbents with good adsorption performance to remove residual tetracycline and other antibiotics in water.

[The effect of heat stress on the cytoskeleton and cell cycle of human umbilical vein endothelial cell in vitro].

OBJECTIVE: To study the effect of heat stress on the cytoskeleton and cell cycle of human umbilical vein endothelial cell ( HUVEC ) in vitro. METHODS: HUVEC was cultured in vitro in 5%CO(2) medium at 37 centigrade ( control group ) or 43 centigrade ( heat stress group ) for 1 hour. Coomassie brilliant blue R-250 staining was used to determine the effect of heat stress on the cytoskeleton. The cells in heat stress group were subsequently cultured at 37 centigradein 5%CO(2) medium after heat stress for 1 hour, and cell cycle of HUVEC was determined at 0, 6, 12, 18 and 24 hours with flow cytometry. RESULTS: Under light microscopy normal cytoskeleton was observed in control group, but thicker and shorter cytoskeleton was found after a rise of temperature, and stress fibers were found in heat stress group. The DNA content of HUVEC at all time points in G0/G1 stage was 38.07%-55.19% after heat stress. The DNA content in control group was 48.57%, and it was 54.06%, 55.19%, 48.23%, 38.07%, and 41.03% at 0, 6, 12, 18, 24 hours in G0/G1 stage in heat stress group. DNA content in S phase was 35.33%-48.18%. The DNA content in control group was 44.62%, and it was 35.33%, 39.50%, 42.50%, 48.18%, and 47.99% at 0, 6, 12, 18, 24 hours in S stage in heat stress group. DNA content in G2/M phase was 5.31%-13.75%. The DNA content in control group was 6.81, and it was 10.61%, 5.31%, 9.27%,13.75%, and 10.98% at 0, 6, 12, 18, 24 hours in G2/M stage in heat stress group. It was demonstrated that compared with control group, the DNA content in G0/G1 stage was significantly increased when the HUVEC were separated from heat stress within 6 hours, and it recovered at a similar level as control group at 12 hours. CONCLUSIONS: Heat stress can change the cytoskeleton of HUVEC, and cause stagnation at G0/G1 stage in cell cycle.

[Chaotic dynamic process of multiple organs dysfunction syndrome and the regulatory function of shenqin liquid on it].

OBJECTIVE: To explore the chaotic dynamic process of multiple organs dysfunction syndrome (MODS) and the regulatory effect of Shenqin Liquid (SQL), a Chinese herbal liquid preparation with the action of purging and qi-tonifying. METHODS: Eighty SD rats were divided into 4 groups, and were given suspension of zymosan A and paraffine (1 mL/kg) by peritoneal injection except for those in the blank control group to set up the multiple organs dysfunction syndrome (MODS) model. Low and high doses SQL were administered twice at the doses of 30 and 60 g/kg of SQL respectively at an interval of 8 h per day before modeling. Serum concentration of tumor necrosis factor alpha (TNF-alpha) and nitric oxide (NO) in MODS model animals were tested diachronically, eg. 12, 6 h before modeling, during modeling, 6 and 12 h after modeling, and then the mathematic models were built up with compartment analysis. Lyapunov exponents (LE) of the mathematic models were calculated to evaluate their chaotic characteristics of movement and the degree of chaos was ascertained with the correlation dimension (CD). RESULTS: The serum levels of TNF-alpha and NO were significantly higher than those in the bland control group at modeling, 6, and 12 h after modeling (P <0.01), while those in the low and high doses of SQL were significantly lower than the model group (P <0.01). Moreover, the level of NO in the high dose of SQL was significantly lower than that in the low dose group (P <0. 01). CD of TNF-alpha movement in the blank control group was 0.803 with the LE less than zero; those in the model group was 1. 966 and > 0 respectively; in the low dose and high dose SQL treated groups, CD was 0.517 and 0.653 respectively and LE >0. CD of NO movement in the blank control group was 0.670 and with LE < 0; in the model group, 1.242 with LE > 0; in the low dose SQL group, 0.574 and in the high dose SQL group 0.850, and LE <0 in the two groups. CONCLUSION: Under the normal physiologic condition, TNF-alpha and NO moved steadily without chaotic properties; while under the pathologic condition of MODS, they manifest relatively complicated chaotic properties. SQL can intervene the movement of TNF-alpha and NO, decrease the complexity of their chaotic movement, and make them return back to a stable state.

Clinical observation on effect of Kaixin capsule in treating 40 patients with diabetic myocardial ischemia.

OBJECTIVE: To observe the effect of Kaixin Capsule (KXC) on myocardial ischemia and plasma endothelin (ET) level in patients with diabetic heart disease (DHD). METHODS: The 72 subjects for observation were randomly selected from inpatients whose diagnosis fit to the standard of DHD. The 32 patients allocated in the control group were treated with conventional Western medicine, and the 40 patients in the treated group were treated with conventional Western medicine in combination with KXC, with the therapeutic course for both groups as 60 days. RESULTS: On ECG, the total effective rate and markedly effective rate in the treated group was 85.0% and 37.5% respectively, higher than those in the control group's 68.7% and 28.1% respectively, and showing significant difference between the two groups (P < 0.05). The level of ET in patients in both groups was significantly higher than normal range, after treatment, but reduced to different extent, and the comparison between them also showed that the difference was significant (P < 0.05). CONCLUSION: KXC might, by way of inhibiting and blocking the release of ET, lower its level in plasma so as to improve the myocardial ischemic condition of patients with DHD.

[The protective effect of high density lipoprotein on the cardiac function of rats with severe burns].

OBJECTIVE: To investigate the protective effect of high density lipoprotein on the cardiac function of rats with severe burns. METHODS: One hundred and thirty-five Wistar rats were employed in the study and were randomly divided into control (n = 15, without treatment), burn (n = 60, with 30% TBSA full-thickness burn on the back) and experimental (n = 60, with the injection of HDL (80 mg/kg) via the caudal vein immediately after burns) groups. The rats in the groups with burn injury were resuscitated with intraperitoneal isotonic saline (50 ml/kg) 30 minutes after burn (PBM). The serum contents of CK, ICAM-1 and TNF-alpha of the rats of all the three groups were determined with corresponding methods. The histological changes in the cardiac muscle tissue of the rats in all groups were observed under light microscope and electronic microscope. RESULTS: The serum contents of CK, ICAM-1 and TNF-alpha in the control group were obviously lower than those in burn group (P < 0.01), while those in experimental group were also markedly lower than those in control group (P < 0.05 or 0.01). The average reduction rate was 36.5%, 32.0% and 12.6%, respectively. The size and the structure of the cardiac muscular fiber in the control group were even and normal. Compared with the burn group, degeneration, inflammatory infiltration and mitochondrial swelling were found to be less marked in the experimental group at 48 PBH, and no focal lysis and necrosis were found, which were observed in the burn group. CONCLUSION: High density lipoprotein can be beneficial to the protection of cardiac tissue in protecting from secondary injury in rats with severe burns.