It has been shown that oxidative stress correlates with atrial fibrillation (AF). The purpose of the present study was to investigate the effects of reactive oxygen species (ROS) on the electrophysiological activity of human atrial myocytes. Right atrial appendages were obtained from patients with AF (AF group, n=12) and without AF (non-AF group, n=12). Single human atrial myocytes were isolated through enzymatic dissociation with type XXIV protease and type V collagenase, then divided into three subgroups: control group (n=12), H2O2 group (0.1, 0.2, 0.5, 0.75, 1, 2, 5, 10 mumol/L, n=7 at each concentration) and vitamin C (antioxidant) group (1 mumol/L, n=7). Ultrarapid delayed rectifier K(+) current (I(Kur)), L-type calcium current (I(Ca,L)) and action potential duration (APD) were recorded by whole-cell patch clamp. In AF control group, the maximum current densities of I(Kur) and I(Ca,L) were significantly lower than that in non-AF control group (both P<0.05) and APD(90) was significantly shorter as well (P<0.05). In both non-AF and AF groups, H2O2 showed two-way concentration-dependent effect on I(Kur) and I(Ca,L). The maximum current densities of I(Kur) and I(Ca,L) was significantly increased at lower H2O2 concentration, but was decreased at higher H2O2 concentration. In non-AF group, 0.2 mumol/L H2O2 caused a peak increase in the maximum current identities of I(Kur) [(8.92+/-0.51) pA/pF, P<0.05] and I(Ca,L) [(9.32+/-0.67) pA/pF, P<0.05]. H2O2 at a concentration higher than 0.75 mumol/L decreased I(Kur) and I(Ca,L). When the H2O2 concentrations were 0.2, 1, 2, 5 and 10 mumol/L, APD(90) was significantly shorter compared with that in non-AF control group (P<0.05), meanwhile it had no significant difference from that in AF control group. In AF group, the peak effective concentration of H2O2 was 0.5 mumol/L, and the turning concentration was 1 mumol/L. The H2O2 concentration-current density curve in AF group was similar to that in non-AF group, but the turning point shifted to the right, indicating that the way that H2O2 acted on ion channels in AF was the same as that in non-AF, however, the sensitivity of ion channels to H2O2 was decreased in AF. Vitamin C reversed these changes induced by H2O2, and did not affect the characteristics of ion channels. H2O2-induced electrophysiological changes in human atrial myocytes were similar to atrial electrical remodeling (AER) in AF, suggesting that ROS might induce AF. Meanwhile, H2O2 also could aggravate AER in AF, contributing to the maintenance of AF. The results suggest that antioxidants might play a significant role in the prevention and treatment of AF.
Action Potentials ; Atrial Fibrillation ; physiopathology ; Calcium ; physiology ; Calcium Channels, L-Type ; physiology ; Delayed Rectifier Potassium Channels ; physiology ; Heart Atria ; cytology ; Humans ; Hydrogen Peroxide ; chemistry ; Myocytes, Cardiac ; physiology ; Patch-Clamp Techniques ; Potassium ; physiology ; Reactive Oxygen Species ; chemistry

Neuronal firing is crucial to the information processing in the nervous system. In order to make a further study of bifurcation scenarios, experiments were performed on neural pacemakers formed at the injured site of rat sciatic nerve subjected to chronic ligatures. We chose the conductance of voltage-dependent potassium ion channels as conditional parameter, and the extracellular calcium concentration as bifurcation parameter, to give a demonstration of how the firing pattern of neural pacemaker responses to dual parameter adjusting. Among 28 preparations observed, 21 were insensitive to dual parameter adjusting since no change of bifurcation scenario structure was detected. On the contrary, the residual 7 preparations showed dramatic bifurcation scenario shifting corresponding to different dual parameter configuration. Briefly, when concentration of 4-aminopyridine (4-AP), a voltage-dependent potassium ion channels blocker, was kept at different level and extracellular Ca2+ concentration was decreased gradually, different bifurcation scenarios of firing patterns were exhibited in an identical neural pacemaker. The two-parameter bifurcation scenarios of experimental neural pacemaker with different parameter configuration were also different. The results show that neural firing pattern is different when the parameter configuration is different, and the bifurcation scenario is a fundamental framework to identify the transitions between firing patterns.
4-Aminopyridine ; pharmacology ; Action Potentials ; physiology ; Animals ; Calcium ; metabolism ; Male ; Neurons ; physiology ; Periodicity ; Potassium Channels ; physiology ; Rats ; Rats, Sprague-Dawley ; Sciatic Nerve ; injuries ; physiopathology

OBJECTIVETo observe the efficacy differences of acupoints massage for asthenopia of video display terminal (VDT) under different exposure dose.

METHODSOne hundred and two cases (204 eyes) were divided into a low exposure group and a high exposure group, fifty-one cases in each group. The same intervention of acupoints massage on Cuanzhu (BL 2), Jingming (BL 1), Sizhukong (TE 23), Sibai (ST 2) and Taiyang(EX-HN 5) were given to the two groups, one acupoint for 5 min and once everyday, one month of which made a course. The symptom score, tear film break-up time (BUT) and Schirmer I test(SIT) were observed before and after treatment.

RESULTS(1) The correlation coefficient of cubic curve model of the exposure dose was the biggest with symptom improvement index (P = 0.000), which indicated that the lower VDT exposure index was, the more obvious the symptom improved. The symptom improvement indices of low exposure group and high exposure group, which were (52.31 +/- 16.65)% and (28.93 +/- 13.35)% respectively, were statistical significant difference (P = 0.000). (2) Compared to before treatment, the levels of BUT and SIT in the two groups were both significantly higher (P < 0.05). Compared with the high exposure group, the levels of BUT and SIT in the low exposure group were increased by 0.826 s (P = 0.022) and 1.029 mm (P = 0.033), respectively, after the impact of BUT and SIT was corrected before the research.

CONCLUSIONThe acupoints massage can improve the symptoms and ocular physiology for patients with VDT asthenpia, and it is more effective for the low exposure cases.

Acupuncture Points ; Adult ; Asthenopia ; physiopathology ; therapy ; Computer Terminals ; utilization ; Female ; Humans ; Male ; Massage ; Middle Aged ; Occupational Diseases ; physiopathology ; therapy ; Tears ; secretion ; Treatment Outcome ; Young Adult

The metalloproteinases/disintegrins in the snake venom act as platelet aggregation inhibitor by an antagonism against integrin on platelet through its RGD sequence and may play other important role in cell-cell fusion, cell matrix interaction and other cellular function. Ussurin is a new metalloproteinase/disintegrin that was cloned from Gloydius ussuriensis. Poly (A+) RNA was purified from the total RNA preparation from venom gland of a single G. ussuriensis using the poly (A+) tract-mRNA isolation system. A cDNA library was constructed with the SMART PCR cDNA library construction kit. The cDNA library was screened and the positive clones were selected. The full-length cDNA of Ussurin was obtained. The cDNA encoding the Ussurin precursor has a 51bp 5'-UTR, the open reading frame of Ussurin and a 490 bp 3'-UTR, the open reading frame of Ussurin cDNA nucleotide sequence is 1434 bp and codes for 478 amino acids with a predicted molecular mass of 53.2 kD and an isoelectric point of 5.37. There is no potential N-glycosylation site in the deduced sequence region. Its deduced amino acid sequence consists of four region, a signal sequence of 18 amino acid residues, a zymogen pro-peptide of 171 amino acid residues with a cysteine switch motif (PK-MCGVT) in it, a central metalloproteinase domain of 201 amino acid residues containing a conserved zinc-chelating sequence (HEXXHXXGXXH) and a methionine-turn CIM involving zinc banding also, a space sequence between metalloproteinase domain and disintegrin domain of 15 amino acid residues with a conserved T392, T397, S400, which is specific residues of the P-II snake venom metalloproteinases, a disintegrin domain of 73 amino acid residues with a characteristic RGD region and six-disulfide bonds. Ussurin belongs to P-II class. The cDNA sequence and deduced amino acid sequence of Ussurin precursor were compared with homologous sequence in the GenBank database, the result reveals high degree of homology in sequence and organization pattern of domain with metalloproteinase/disintegrin gene family of other snake species. Compared with the alignment of amino acid sequence of metalloproteinase/disintegrin member, hypervariable regions of this member were revealed, besides they share higher homologous in the zymogen domain. It suggests that the hypervariable regions are the counterparts directly suitable for interacting with different domain of receptors, different receptors or substrates.
Amino Acid Sequence ; Animals ; Base Sequence ; Cloning, Molecular ; Disintegrins ; chemistry ; genetics ; metabolism ; Metalloproteases ; chemistry ; genetics ; metabolism ; Molecular Sequence Data ; Sequence Alignment ; Viper Venoms ; enzymology ; genetics ; Viperidae ; genetics ; metabolism

OBJECTIVETo investigate the effect of nano-TiO(2) intratracheal instillation on the progression of dyslipidemia and atherosclerosis in apolipoprotein E-knockout mice.

METHODSThe nano-TiO(2) was ultrasound with phosphate-buffered saline solutions (PBS) into its suspension for exposure. A total of 46 specific pathogen free (SPF) level of 11-week-old male apolipoprotein E-knockout mice were randomly divided into groups by their body weights: non-treatment group (8 mice), PBS control group (9 mice), high dose group (1.0 mg/ml, 10 mice), medium dose group (0.5 mg/ml, 10 mice), and low dose group (0.1 mg/ml, 9 mice). Except the non-treatment group, mice from other groups were intratracheally instilled with 0.05 ml each time, twice a week. After exposure of 6 weeks, viscera index, blood TC, TG, HDL-C, LDL-C, and organic lipid ratio were assessed as biomarkers. Artery and aortic root issues were assessed by histopathology.

RESULTSAfter 5 weeks exposure, mice body weights in high dose group ((29.7 ± 1.9) g) started to drop, compared to PBS control ((31.3 ± 1.9) g, t = -1.58, P < 0.05) and low dose group ((31.4 ± 1.4) g, t = -1.17, P < 0.05); after 6 weeks, high dose group ((28.8 ± 1.5) g) was lower than PBS control ((30.4 ± 1.9) g, t = -1.60, P < 0.05), non-treatment group ((30.2 ± 1.3) g, t = -1.43, P < 0.05) and low dose group ((30.6 ± 1.0) g, t = -1.83, P < 0.05). TC levels of non-treatment, PBS control, high dose group, medium dose group and low dose group were (2.92 ± 1.18), (3.12 ± 0.73), (4.19 ± 1.86), (3.46 ± 0.72) and (2.57 ± 0.64) mmol/L, respectively; TG levels were (0.39 ± 0.13), (0.39 ± 0.08), (0.60 ± 0.21), (0.55 ± 0.19) and (0.41 ± 0.11) mmol/L, respectively; HDL-C levels were (1.67 ± 0.45), (1.54 ± 0.67), (0.93 ± 0.50), (1.02 ± 0.48) and (1.31 ± 0.64) mmol/L; TG levels of high dose group were higher than that of non-treatment group (t = 1.27, P = 0.03) and low dose group (t = 1.62, P = 0.01); TG levels of medium dose group was higher than PBS control (t = 0.16, P = 0.04), and TC levels of high dose group were higher than PBS control (t = 0.22, P = 0.01), non-treatment group (t = 0.22, P = 0.04) and low dose group (t = 0.20, P = 0.03), and HDL-C levels of high dose group were lower than PBS control (t = -0.61, P = 0.04) and non-treatment group (t = -0.74, P = 0.04); organic lipid ratio of each group were (2.27 ± 0.51)%, (2.06 ± 0.53)%, (2.90 ± 0.50)%, (2.60 ± 0.23)%, (2.24 ± 0.45)%; high dose group were higher than PBS control (t = 0.85, P = 0.00), non-treatment group (t = 0.64, P = 0.03) and low dose group (t = 0.67, P = 0.01); medium dose group was higher than PBS control (t = 0.54, P = 0.02). The plaque lipid content and calcium content which showed the progression of atherosclerosis and plaque rupture were elevated in medium and high dose groups.

CONCLUSIONIntratracheal instillation of nano-TiO(2) can induce dyslipidemia and accelerate the development of atherosclerosis and plaque rupture in ApoE-/-mice.

Animals ; Apolipoproteins E ; genetics ; Atherosclerosis ; blood ; chemically induced ; Dyslipidemias ; blood ; chemically induced ; Instillation, Drug ; Lipid Metabolism ; Lipids ; blood ; Male ; Mice ; Mice, Knockout ; Nanoparticles ; Specific Pathogen-Free Organisms ; Titanium ; administration & dosage ; pharmacology

OBJECTIVETo study the NK/T-cell lymphoma, search for a more efficacious and simpler method and establish a standard guideline for distinguishing the NK-like T-cell lymphoma from the NK-cell lymphoma.

METHODSThirty-four NK or T-cell lymphomas from the upper aerodigestive tract (n = 22), skin (n = 2), gastrointestinal (GI) tract (n = 2), lymph nodes (n = 7), and other sites (n = 1) were studied. Immunophenotype was analyzed by immunohistochemistry. In situ hybridization with EBER 1/2 RNA probes was performed. T-cell receptor (TCR)-beta and -gamma gene rearrangement was analyzed by polymerase chain reaction (PCR).

RESULTSEighteen cases were positive for CD(56) and 16 for TIA-1 in 34 lymphomas cases. All tumor cells in the skin cases were positive for Ki-67. Epstein-Barr virus (EBV) mRNA was detected in 12 upper aerodigestive tumors including 9 of 12 nasal and 3 extranasal tumors. EBER was also detected in 1 of 2 skin lymphomas and both of the 2 GI lymphomas. Clonal TCR-beta and -gamma gene rearrangement was detected in 2 of 22 upper aerodigestive, all of the skin and GI lymphomas, and 6 of 9 nodal and other site lymphomas.

CONCLUSIONMost upper aerodigestive NK/T-cell lymphomas are genotypically NK derivation, and a few belong to T lineage. However, NK-like T-cell lymphomas more frequently seen in skin and GI tract. Nodal NK-cell lymphoma are quite rare. These two kinds of lymphomas can only be diagnosed with additional immunohistochemical markers, EBER detection by ISH, TCR gene rearrangement or NK-cell receptors (NKRs) RNA detection. Detection of TCR rearrangement remains the important standard for the diagnosis of T-cell lymphoma.

Adolescent ; Adult ; Aged ; Child ; Female ; Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor ; Herpesvirus 4, Human ; isolation & purification ; Humans ; Immunophenotyping ; Killer Cells, Natural ; pathology ; Lymphoma, T-Cell ; genetics ; immunology ; pathology ; Male ; Middle Aged

OBJECTIVETo establish a novel and useful rabbit model of lumbar disc degeneration using microinjection of fibronectin fragment (Fn-f).

METHODSThirty-two New Zealand white rabbits underwent injection of N-terminal 30 kDa Fn-f (experimental group) or phosphate buffered saline (PBS) (control group) into the central region of L1-2, L2-3, L3-4, L4-5 discs using a 32-gauge microsyringe. Two rabbits (blank group) with no treatments were sacrificed to examine the proteoglycan synthesis of neucleus pulposus (NP) using (35)S-sulfate incorporation assay. At the 4-, 8-, 12-, and 16-week time points, the discs were examined histologically, radiographically, and with proteoglycan synthesis.

RESULTSHistology demonstrated a progressive loss of the cell numbers in NP and architecture destruction in NP and anulus fibrosus (AF) in Fn-f-injected discs over the 16-week study period. The NP regions in Fn-f-injected discs shrinked distinctly after the 4-week time point, and were not discernible with the inner AF by the 16-week time point. Protoglycan synthesis in Fn-f-injected discs decreased progressively (F = 263.241, P = 0.000). At each time point, the Fn-f-injected discs showed significantly decreased proteoglycan synthesis compared with controls (t = -27.010 - -2.833, P < 0.05). The DHI% of the Fn-f-injected discs at the 4-, 8-, 12-, and 16-week time points were 96.5% ± 1.7%, 85.6% ± 3.8%, 77.2% ± 3.5% and 65.5% ± 5.6%, respectively. Comparing with the DHI% of PBS-injected discs (97.4% ± 1.2%), the Fn-f-injected discs exihibited no significant differences in disc heights at the 4-week time point (P > 0.05), but significant decreases in disc heights at the 8-, 12-, and 16-week time points (t = -21.225 - -10.795, P < 0.01). Apparent anterior osteophytes formed at the 12-week time point and enlarged remarkablely by the 16-week time point in the experimental spines.

CONCLUSIONSFn-f can induce a progressively degenerative process in rabbit discs which is ethical, cost-effective, reproducible, and consistent with the spontaneous degeneration in human. And it seem to be a novel and useful model for the study of disc degeneration at the molecular level.

Animals ; Disease Models, Animal ; Fibronectins ; pharmacology ; Intervertebral Disc Degeneration ; chemically induced ; Lumbar Vertebrae ; Rabbits ; Random Allocation

OBJECTIVETo explore the way of stably inducing canine bone marrow mesenchymal stem cells (BMSCs) to differentiate into fibroblasts and myofibroblasts in vitro, and provide seed cells for fabricating tissue engineering heart valves (TEHV).

METHODSAdult canine BMSCs were separated by a gradient centrifugation on Percoll (density 1.073 g/ml), then the cells were incubated in low-glucose Dulbecco Eagle's minimum essential medium (LG-DMEM) with 10% bovine calf serum. Cell phenotype were identified by immunohistochemistry staining. The second and third generation of BMSCs were committedly induced by conditioning culture medium, which were detected by immunohistochemistry staining. The induced-BMSCs were freezed, preserved and resuscitated after 7 d to observe the cell growth, proliferation and function.

RESULTSBMSCs deriving from the bone marrow mononuclear cells separated by a Percoll gradient were positive expression of alpha-smooth muscle antibody, vimentin and negative expression of CD34, laminin. About (50 +/- 3)% induced-BMSCs were positive expression of laminin. Approximately (85 +/- 3)% freezed induced-BMSCs could be resuscitated. And the growth, proliferation and function were well.

CONCLUSIONBMSCs could be committedly induced to differentiate into fibroblasts and myofibroblasts in vitro. It is suitable to be the seed cells.

Animals ; Cell Culture Techniques ; methods ; Cell Differentiation ; Dogs ; Fibroblasts ; cytology ; Mesenchymal Stromal Cells ; cytology ; Monocytes ; cytology ; Myoblasts ; cytology

Objective To study the changes of risk factors of cardiovascular disease in the rural community population after intervention. Methods The Beijing Fangshan cardiovascular prevention program was a community-based comprehensive intervention study which was launched from 1991 and ended in 2000 in five communities including three as intervention communities (IC) and two as control communities (CC) in Fangshan, Beijing suburb. The intervention measures were focused on health education and hypertension control. The changes of risk factors of cardiovascular disease in IC and CC were analyzed using random sample in the year 1991, 1995 and 1999, respectively. The risk factors include systolic and diastolic blood pressure(SBP and DBP), body mass index(BMI), serum total cholesterol(TC), triglyceride(TG),high-density lipoprotein cholesterol(HDL), smoking, and drinking. Results From the year 1991 to 1999, the risk factors of cardiovascular disease such as SBP, DBP, smoking rate and drinking rate were reduced in the population of IC. For male in IC, the decline of SBP, DBP, smoking rate, and drinking rate were 1.6 mmHg, 1.1 mmHg, 14. 5% ( P ＜ 0. 01) and 3.7%, respectively. For female of IC, SBP and DBP declined 4.8 mmHg ( P＜0.01) and 3.2 mmHg ( P ＜0. 01), respectively. SBP, DBP and smoking rate in the population of CC had a little reduction while BMI, TC and TG increased in both IC and CC. During the period of 1991 to 1999, most cardiovascular risk factors in the population of IC had net reduction compared to that of CC. Conclusions Except for BMI and lipids, rural community intervention, as focused on health education and hypertension control, has resulted in the reduction of most risk factors of cardiovascular disease.

Objective　To observe the characteristics and rules of craniocerebral injury resulting from a high explosive shell to provide the bases for treating explosive injury. Methods　A total of 36 sheep were distributed at the distance 6 to 48 m away from the explosive center and the shell was exploded electrically at 7 m above the earth. At the same time, the velocity of fragments and shock wave pressure were determined. Gross and pathological observations were performed after injury. Results　Among all sheep with fragment injury, craniocerebral injury was 32%. Their immediate death rate was 75% and all died 6 h later. The incidence rates of penetrating wound and blind wound were 75% and 25% respectively. Pollution of wound track was heavy. The percentage of head lost was 50% in sheep and 50% of injured animal suffered from comminuted fracture of skull base. Bleeding was found extensively on the surface of the cerebrum, even medulla oblongata was involved. Hemorrhage, edema, rupture of small blood vessels and degeneration of neuron were found at the regions 4 cm away from the wound tract with light microscopy. Combined blast injury was found and occurred most often in the abdomen and limbs, both accounting for 62.5%, and combined thoracic injury was the third, up to 50%. All the animals of craniocerebral injury combined with lung blast injury. Conclusion　High explosive shells destroy cranium badly and extensively. Many skulls are lost and the cranial base is readily fractured. The wound track is heavily polluted. Combined injury is more often occurred.