OBJECTIVETo explore the alterations of after depolarization and triggered activity in myocardiac muscle during progression of mouse aortic stenosis.

METHODSAfter the establishment of mouse aortic stenosis model, the heart was collected and intracellular potential was recorded using standard glass microelectrode. After the recording, the action potential (AP), early after depolarization (EAD), delayed after depolarization (DAD) in papillary muscles were analysed.

RESULTS(1) Compared with that of time-matched control mice, there were no changes of the action potoutial duration at 90% repolarization(APD90) in model mice at 2 and 5 weeks, whereas the APD90 was progressively prolonged at 9 and 13 weeks. (2) During the 30 minites of the experiment, spontaneous EADs and DADs were frequently present in medel mice at 9 and 13 weeks, were not in control and model mice at 2 and 5 weeks. (3) Compared with those of control group, EADs and DADs triggered by hypokalaemia or isoproterenol were increased significantly. The incidence rate of triggering EADs and DADs was progressively increased over time.

CONCLUSIONEAD, DAD and trigger activities increase gradually during the process of aortic stenosis, and it suggests that the myocardium electrical-instability is markedly increased in the insult hearts.

Action Potentials ; physiology ; Animals ; Aortic Valve Stenosis ; physiopathology ; Disease Models, Animal ; Male ; Mice ; Myocytes, Cardiac ; physiology

OBJECTIVETo find the characteristic parameters from electrocardiogram (ECG) which is most related to pathological progress, surface ECG was performed in mice at 2, 5, 9 and 13 week post surgery.

METHODSElectrocardiogram recordings: The mice were anaesthetized with tribromoethanol (250 mg/kg, i.p.). Lead II surface ECG were acquired by using the Biopac System MP150 at a rate of 5 kHz.

RESULTS(1) No arrhythmia was observed in Sham and 2-week Band mice. Spontaneous arrhythmias were observed in ECG recordings, with an incidence of 15%, 28% and 63% in 5-, 9- and 13-week Band mice, respectively. Tachyarrhythmias, such as frequent premature ventricular extrasystole, bigeminy, trigeminy, and paroxysmal tachycardia were found. (2) Analysis of ECG recordings revealed a significant prolongation of QT and QTc intervals. Compared with age-matched Sham mice, the increment in QT and QTc intervals was 20.4%, 32.7%, 49.7%, 61.0% and 27.1%, 32.1%, 43.9%, 59.1% at 2, 5, 9 and 13 week, respectively (P < 0.01). (3) The characteristic change in electrocardiogram was on the J wave. The amplitude of J wave was upward in Sham mice, and it was significantly flattened or inverted in Band mice. (4) Except that RR interval at 2 week showed a slight decrease, there was no significant change in PR interval and RR interval in Band mice.

CONCLUSIONIn the present study, we found that the increase incidence of spontaneous arrhythmias, prologation of QT interval and changes in the amplitude of the J wave in the surface ECG during progression of mouse cardiac hypertrophy and failure, and the progressive pattern indicated that a gradual aggravation of the ventricular repolarization delay in this mouse model.

Animals ; Cardiomegaly ; physiopathology ; Disease Models, Animal ; Electrocardiography ; Male ; Mice

Objective To study the effect of the custom of long term chewing lime tobacco on human tooth enamel electron spin resonance (ESR) dosimetry. Methods A total of 20 enamel samples from lingual parts of adults teeth collected in Bombay, India were obtained by mechanical method. Some enamel samples from Japanese adults were extracted and 10 mixed samples were prepared. Enamel samples were exposed to different doses of 60Co γ-rays several times, and ESR spectra were measured after exposure. Results ESR background signals of 9 Bombay samples were found 1.5-3.3 times higher than those of Japanese mixed samples. The γ-ray dose responses of dosimetric signal with higher background level were a little lower, and the average sensitivity was (0.42 ± 0.03 )mGy, which was close to that of Japanese mixed samples. Conclusions The average level of background signals of Bombay samples was much higher than that of other non-chewing tobacco area, which was possibly caused by tobacco lime, the main component in chewing tobacco productions, and it would help to explore its special influences on ESR, and improve dose reconstruction in accuracy.

BACKGROUND: Osteogenic growth peptide (OGP) is a newly discovered growth factor to promote osteogenesis, the effect on proliferation and differentiation of bone marrow stromal cells (MSCs) arouses more and more attention.OBJECTIVE: To elucidate the effect of OGP on proliferation and differentiation of MSCs in vitro.DESIGN, TIME AND SETTING: A randomized COntrol experiment was performed at the Key Laboratory for Oral Biomedical Engineering by the State Ministry of Education from February to June 2006.MATERIALS: A 6-month-old male Sprague-Dawley rat was used for the extraction of MSCs; and OGP was provided by Sigma Company, USA.METHODS: MSCs were cultured individually in a-MEM medium containing various COncentrations of OGP (10-11 mol/L,10-10 mol/L, 10-9 mol/L, 10-8 mol/L and 10-7 mol/L) and fetal bovine serum. The cells in the control group were cultured with α-MEM medium containing FBS alone.MAIN OUTCOME MEASURES: Identification of MSCs; cell proliferation using MTT method; alkaline phosphatase (ALP) activity using enzyme-linked immunosorbent assay; core binding factorα1 (Cbfa1) mRNA expression using RT-PCR.RESULTS: The addition of OGP resulted in an increase of cell proliferation (10-9mol/L OGP, P < 0.05), ALP activity (10-8 mol/LOGP, P < 0.05) and Cbfal mRNA expression (P < 0.05).CONCLUSION: OGP stimulates proliferation and sequential differentiation of MSCs via inducing Cbfal mRNA expression.

One hundred and thirty-six adult patients with type 2 diabetes ( ≥40 years, body mass index > 24) were assigned to the low-dose Mefformin, high-dose Mefformin, and control groups. Plasma lactic acid level was detected with ultraviolet enzyme kinetics assay. Our data showed that plasma lactic acid of the low-dose or high-dose mefformin group was significantly higher than the control group (2.314 vs. 2.511, P<0.05 ), although there was no significant difference between the low-dose and the high-dose Mefformin group. In all the 3 groups, increased lactic acid ( > 2. 2 mmol/L) was found in some patients ( Mefformin group vs. Control group: X2 = 7.43, P < 0.05 ), and no lactic acid > 5.0 mmol/L was found. Insulin resistance index and hemoglobin Alc were similar between the 3 groups. Thus, mefformin may not increase the risk of lactic acidosis in diabetic patients with normal cardiorespiratory and renal function.

Objective To evaluate the effect of surgical treatment in ischemic cerebrovascular disease using perfusion-weighted magnetic resonance imaging (PWI) technique.Methods The clinical and imaging data of 24 patients with ischemic cerebrovascular disease were analyzed retrospectively. Cerebral perfusion was compared before and after operation by PWI.Results In our series, there were 9 cases of stenosis or occlusion of unilateral internal carotid artery (ICA), 8 cases of unilateral stenosis or occlusion of middle cerebral artery (MCA), 5 cases of multiple stenoses of intra- or extracranial artery system, 2 cases of moyamoya disease. PWI revealed 1 case of normal regional cerebral blood flow (rCBF) and mean transit time (MTT), 15cases of normal rCBF with increased MTT, and 8 cases of decreased rCBF with increased MTT. 23 patients received surgical treatment. There were 13 patients performed by stent angioplasty, 4 patients by endarterectomy, and 6 patients by STA-MCA bypass surgery. Cerebral perfusion improved in 19 cases (82.6%), which included 12 cases (92.3%) performed with stent angioplasty, 4 cases (100%) with endarterectomy and 3 cases (50%) with STA-MCA bypass surgery.Conclusions Being a new type of examination, PWI is helpful to evaluate the status of cerebral perfusion. Surgical methods are effective in treatment of ischemic cerebrovascular disease.

With the progress and development of science and technology, biomedical technology has been widely used in traditional Chinese medicine (TCM) research. However, TCM and Western medicine developed and came into being at different times and from different cultural backgrounds. Their targets are to study and explore the objective laws of human life activities from different angles and by different means. To study and evaluate TCM simply by the diagnosis and treatment standards of Western medicine cannot truly reflect the characteristics of TCM. Lots of clinical phenomena in the diagnosis and treatment in TCM cannot be revealed scientifically. It might be a significant pattern to combine the study of TCM with Western medicine, based on double-screening model of combining disease with syndrome types, following up evidence-based medical research steps, and making use of systematic review and data mining to analyze the inherent laws of TCM symptoms.

Objective To investigate the incidence and structure of mental disability in children with movement disorders. Methods 157 children with movement disorders (103 with cerebral palsy and 54 with mental retardation) were assessed with Gesell developmental schedules,and mental disability was identified as development quotient (DQ)<75. Results The incidence of intelligence disability was 92.2% in children with cerebral palsy, including 91.2% in spastic type, and 100% in dyskinetic, mixed or dystonic type. The development of gross motor was retarded in children with spastic cerebral palsy, and gross and fine motor in children with dyskinetic cerebral palsy, compared with those with mental retardation. Conclusion It is important to focus the mental development in children with movement disorders, especially the dyskinetic cerebral palsy. Gesell developmental schedules should be used carefully to assess the mental development in children with movement disorder.

The tuberous roots of Aconitum carmichaeli are largely used in traditional Chinese medicine and widely grown in Jiangyou, Sichuan, China. During the growth process, this medicinal plant releases a large amount of allelochemicals into soil, which retard the growth and development of near and late crops. Therefore, a pure culture experiment was thus carried out by seed soaking to study the allelopathic effects of extracts from tuberous roots of A. carmichaeli (ETR) on the seed germination and young seedling growth of Lolium perenne, Trifolium repens, and Medicago sativa, the late pasture grasses after cultivation of A. carmichaeli. The results showed that three pasture grasses varied significantly in seed germination and young seedling growth in response to ETR concentrations. Seed germination of M. sativa was stimulated by low ERT concentration (0.01 x g(-1)), while all of pasture grass seeds germinated poorly in solution with 1.00 g x L(-1). Seed soaking with 1.00 g x L(-1) also inhibited significantly the growth of pasture young seedlings, with M. sativa showing the highest seedling height reduction of 42.05% in seeding height, followed by T. repens (40.21%) and L. perenne with about 11%. Cultivation of L. perenne could thus be beneficial to increase whole land productivity in A. carmichaeli-pasture grass cropping systems. In addition, hydrolysis of protein, starch, and inositol phosphates was blocked and free amino acids, soluble sugars and phosphorus were decreased in seeds by seed soaking with ETR, which could be one of the reason for the inhibition of seed germination. There was a significant reduction in root vigor, nitrate reductase, and chlorophyll after the seed treatment with ETR, indicating the suppression of nutrient uptake, nitrate assimilation, and photosynthesis by allelopathic chemicals in ETR, which could lead to the slow growth rate of pasture grass seedlings.
Aconitum ; chemistry ; metabolism ; Allelopathy ; China ; Pheromones ; metabolism ; pharmacology ; Plant Extracts ; metabolism ; pharmacology ; Plant Roots ; chemistry ; metabolism ; Poaceae ; drug effects ; growth & development

AIM: To investigate the effects of radix pseudostellariae on cardiac function and matrix metalloproteinases(MMPs) in rat chronic heart failure induced by coronary artery ligation.METHODS: Rat model of chronic heart failure was produced by ligating the coronary artery for 6 weeks.The cardiac functions were determined by observing the hemodynamics parameters.mRNA expressions of MMP-2 and MMP-9 in left ventricular tissue were detected by RT-PCR and activities of MMPs were assayed by zemography.RESULTS: Cardiac function was remarkable turbulence after coronary artery ligation 6 weeks,according to the results of the hemodynamics.The mRNA contents and activities of MMP-2 and MMP-9 in left ventricular tissue were significantly elevated.Radix pseudostellariae remarkable ameliorated the cardiac functions,inhibited the mRNA contents and activities of MMP-2 and MMP-9 in left ventricular tissue of rat with chronic heart failure after continued 5 weeks treated with decoction of radix pseudostellariae.CONCLUSION: The decoction of radix pseudostellariae ameliorates cardiac functions of rat with chronic heart failure.The mechanism maybe involves in the inhibition of the MMP-2 and MMP-9 mRNA expression and activities in cardiac ventricles.