Biomedical subjects

Gangmin Ning

Publications and source records attributed to Gangmin Ning.

6 recordsLinked to original sources

PubMed2006

Artificial neural network based model for cardiovascular risk stratification in hypertension.

This study was to develop an objective method to stratify cardiovascular risk in hypertension. Stratification for cardiovascular risk is crucial in deciding treatment strategy for hypertension but has yielded undesirable results in clinic due to its low accuracy which is caused by physicians' subjective experience and the uncertainty of patients' statements. Our model proposed herein overcomes these disadvantages by applying artificial neural network based on a classic back propagation net. The model input is derived from the clinical investigation. The target output is the stratification level of total cardiovascular risk, which is learned from the guidelines of hypertension treatment. Study in 348 normotensive and hypertensive subjects showed that the results of model stratification are consistent with the standard stratification suggested by hypertension guidelines in 81.61% cases. The results confirm the accuracy of the model and demonstrate its ability in risk evaluation for hypertension.

Algorithms↗

PubMed2006

Study on the technology of nitric oxide (NO) detection in vitro and in vivo.

To reveal the intracellular distribution of nitric oxide (NO) in single cell and to detect NO quantitatively in animal models, various methods are developed. A confocal microscope and 3D visualization technique were applied to visualize NO concentration in arbitrary directions and in different sections of cells. It was shown that NO distributions in cultured neurons of rat hipopocampus were not homogeneous. A kind of highly sensitive and selective NO electrode was utilized to measure the NO concentration in SD rat hippocampus, simultaneously with blood pressure and ECG recording. By the administration of N(G)-nitro-L-arginine methylester (L-NAME), the changes of NO level in the hippocampus in vivo were detected. It was shown that the NO level decreased greatly when NOS was inhibited by L-NAME with significant increase in blood pressure. The developed methods may be helpful to investigate the physiological mechanism of NO and its role in pathology.

Animals↗

PubMed2006

Investigation of beat-to-beat cardiovascular activity of rats by radio telemetry.

This paper was aimed to apply telemetry technology to investigate the cardiovascular activity of rats. A subminiature radio transducer was implanted in the body of rat to measure beat to beat blood pressure, ECG, body temperature, as well as the activity of rat continuously. Mathematic tools were developed to extract beat to beat cardiovascular parameters. Accordingly, spectral analysis of blood pressure variability and heart rate variability was performed to analyze cardiovascular activity in both normotensive and hypertensive rats. New indices were also established to assess the fluctuation of blood pressure of hypertensive rats and thus the effect of anti-hypertensive medication. The ratio of low frequency power to high frequency power in heart rate variability of normotensive rats was much lower than that of hypertensive rats. In hypertensive rats, the blood pressure variability demonstrated significant increase. Furthermore, the circadian rhythm of blood pressure and heart rate variability also altered in hypertensive rats. After the treatment, the blood pressure of hypertensive rats dropped significantly. Meanwhile, the developed indices, such as 24 h smoothness index were consistent with the behavior of blood pressure satisfactorily. The results suggest that the developed methods are powerful in studying cardiovascular system as well as evaluating the effects of antihypertensive medication objectively.

Animals↗

PubMed2006

[Analysis of rat 24h heart rate variability based on telemetry technology].

In this study ECG signal of unstrained rat was recorded by telemetry device, and heart rate variability (HRV) was analyzed in order to evaluate 24h autonomic nervous activity. The results demonstrated an obvious circadian rhythm in the autonomic nervous activity: sympathetic activity being dominant during wake phase, and parasympathetic activity, dominant during sleep phase. The ratio of the low frequency to high frequency components in HRV power spectrum (LF/HF) fluctuates with the change in the sleep stages. It is concluded that 24h HRV analyses may reveal plentiful information about the behavior of autonomic nervous system and thus facilitate the investigation of its regulating role in physiological and pathological processes.

Animals↗

PubMed2004

Nitric oxide imaging in neurons using confocal microscopy.

The instability and low concentration of nitric oxide (NO) in specimens make it difficult to be detected directly. In this chapter, a method for imaging nitric oxide using laser scanning confocal microscopy (LSCM) is presented. A cultured hippocampal neuron is dyed with DAF-2 and observed under a Zeiss LSM 510 laser scanning confocal microscope. A 488-nm laser power is applied as excitation and the emission light from the labeled nitric oxide in the neuron is detected. In this way, nitric oxide is imaged and its intracellular kinetic change is monitored. Furthermore, image processing and visualization techniques are employed to help analyze the image data.

Animals↗

PubMed2003

Inhibitory effect of jujuboside A on glutamate-mediated excitatory signal pathway in hippocampus.

Jujuboside A (JuA) is a main component of jujubogenin extracted from the seed of Ziziphus jujuba Mill var spinosa (Bunge) Hu ex H F Chou (Ziziphus), which is widely used in Chinese traditional medicine for the treatment of insomnia and anxiety. Previously, we reported the inhibitory effects of JuA on hippocampal formation in vivo and in vitro, the present study was carried out to examine the effects of JuA on glutamate (Glu)-mediated excitatory signal pathway in hippocampus. Microdialysis coupled with high-performance liquid chromatography (HPLC) was used to monitor the changes of Glu levels in the hippocampus induced by penicillin sodium, or a mixture of penicillin sodium and JuA. The results showed that penicillin increased the hippocampal Glu concentration (p < 0.01) and a high dose of JuA (0.1 g/L) significantly blocked penicillin-induced Glu release (p < 0.05). Moreover, the effect of JuA on intracellular Ca2+ changes after the stimulation by Glu was studied in cultured hippocampal neurons with confocal laser scanning microscope (CLSM). It was found that Glu (0.5 mM) induced an intracellular [Ca2+]i increase (p < 0.01), and JuA significantly inhibited the Glu-induced Ca2+ increase. The calmodulin (CaM) antagonist trifluoperazine (TFP) showed a similar inhibitory effect as JuA. These observations suggested that JuA has inhibitory effects on Glu-mediated excitatory signal pathway in hippocampus and probably acts through its anti-calmodulin action.

Animals↗