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Biomedical subjects

J Y Ren

Publications and source records attributed to J Y Ren.

6 recordsLinked to original sources
PubMed2004

Free radical EPR spectroscopy analysis using blind source separation.

In this paper, we propose a novel approach for electron paramagnetic resonance (EPR) mixture spectra analysis based on blind source separation (BSS) technique. EPR spectrum of a free radical is often superimposed by overlapping spectra of other species. It is important and challenging to accurately identify and quantify the 'pure' spectra from such mixtures. In this study, an automated BSS method implementing independent component analysis is used to extract the components from mixed EPR spectra that contain overlapping components of different paramagnetic centers. To apply this method, there is no requirement to know the component spectra or the number of components in advance. The method is applied to analyze free radical EPR spectra which are collected from standard chemical system, cultured cell suspense, and ex vivo rat kidneys by spin trapping EPR technique. Results show that the BSS method proposed here is capable of identifying the component EPR spectra from mixtures with unknown compositions. The BSS technique can offer powerful aids in resolving spectral overlapping problems in general EPR spectroscopy analysis.

Algorithms↗
PubMed2001

Reference data and predictive diagnostic models for calcaneus bone mineral density measured with single-energy X-ray absorptiometry in 7428 Chinese.

Calcaneus bone mineral density (BMD) of 7428 Chinese (4126 women, 3302 men; aged 22-94 years) was measured using single-energy X-ray absorptiometry (SXA). A reference range of calcaneus BMD values for healthy Chinese men and women was established and the usefulness of this method for screening and diagnosis in osteoporosis was evaluated. The peak BMD occurred at 20-24 years old and peak BMD in women was significantly lower than in men. BMD loss in the calcaneus started at the age of 35 years for women, and at 63 years in men. BMD loss rate was 1.2%/year for women and 0.56%/year for men after 50 years. The young normal reference for calcaneus BMD was 442.1+/-69.6 mg/cm2 for men and 388.3+/-61.7 mg/cm2 for women calculated from the mean BMD value of subjects whose age ranged from 20 to 49 years. The accumulated BMD loss in the calcaneus is similar to that of Ward's triangle. Multiple linear regression showed that both age and weight were important factors. The incidence of osteoporosis in older men and women (> or = 60 years) is 6.6% and 32.1% respectively. We conclude that calcaneus BMD measurement is useful and sensitive for the screening and diagnosis of osteoporosis. A predictive diagnostic model for osteoporosis based on the calcaneus was constructed using multiple linear regression and the WHO criteria for diagnosing osteoporosis can be applied to calcaneus BMD.

Absorptiometry, Photon↗
PubMed2001

[Comparative study on efficacy of qinggan granule and bushen granule in treating chronic hepatitis C].

OBJECTIVE: To evaluate the efficacy of Qinggan Granule (QGG) and Bushen Granule (BSG) in treating chronic hepatitis C (CHC) from blood donors clinically, biochemically and pathologically as well as to explore the therapeutical principle and methods of TCM. METHODS: Sixty-six patients with CHC were divided into three groups, the 36 patients in the QGG group treated with QGG, the 18 patients in the BSG group treated with BSG and the 12 patients in the control group untreated. The dose of QGG and BSG given was 30 g each time, three times per day for 6 consecutive months. Clinical and serum biochemical parameters as well as pathological change of liver biopsy before and after treatment were observed dynamically and compared. RESULTS: After treatment, in the two treated group, clinical symptoms were improved significantly, alanine transaminase (ALT) and aspartate aminotransferase (AST) reduced markedly. Moreover, QGG showed the effects of increasing albumin and lowering alkaline phosphatase (ALP). On the contrary, ALT still remained as before but AST further increased in the control group. Pathological examination showed that the inflammatory grade (IG) decreased in 42.2% and fibrotic stage (FS) decreased 21.2% of the patients in the QGG group, but no significant changes of the two indexes occurred in the BSG group, while in the control group, IG unchanged and FS increased in 3 cases. Chevallier's semi-quantity system analysis showed significant decrease of both scores in the QGG group (P < 0.05), only decrease of IG in the BSG group, and slight raise of IG and significant increase of FS (P < 0.05) in the control group. CONCLUSION: Condition of chronic hepatitis C patient would deteriorate progressively if not treated in time, especially the development of fibrosis. QGG and BSG could improve the clinical symptoms significantly, lower ALT and AST, eliminate inflammatory damage in the liver, slow down or reverse liver fibrosis process with stable long-term effect. Though most of the patients present a Syndrome of Liver-Kidney Yin-deficiency, the effect of QGG is superior to that of BSG, suggesting that the treatment of CHC should mainly be clearing principle, and method of clearing Liver and eliminating Dampness may be more suitable for them.

Adult↗
PubMed1997

Effects of berberine of L- and T-type calcium channels in guinea pig ventricular myocytes.

AIM: To study the effects of berberine (Ber) on L-(ICa,L) and T-type (ICa,T) channels in isolated guinea pig ventricular myocytes. METHODS: Using whole cell patch-clamp recording technique. RESULTS: Ber 10, 30 mumol.L-1 inhibited the ICa, L from 1400 +/- 247 pA to 978 +/- 204 pA (n = 5 cells of 5 guinea pigs, P < 0.05), and to 664 +/- 179 pA (n = 5, P < 0.01), respectively. The inhibitory effect was concentration-dependent and non-frequency-dependent. The peak value of ICa,L in the current-voltage relationship was decreased. Ber affected the inactivation kinetics of ICa,L. The half activation potential (V0.5) was shifted from -27.8 mV to -34.2 mV and the slope factor (kappa) was changed from 9.22 into 13.03. Ber did not affect the activation kinetics. Ber 10 and 30 mumol.L-1 also inhibited ICa,T (from 154 +/- 80 pA to 101 +/- 78 pA, and to 48 +/- 45 pA, n = 8 cells of 5 guinea pigs, P < 0.05). CONCLUSION: Ber possessed blocking effects on both L- and T-type calcium channels.

Animals↗
PubMed1997

The new model of age-dependent changes in bone mineral density.

To theoretically and quantitively describe the phenomena that bone mineral density (BMD) was changed with, the three-exponential model was proposed. Our results showed that BMD in radius and ulna in a sample of 36,879 healthy people ranging in age from 2 to 100 years fit the three-exponential equation well. Bone mass loss in Chinese women was faster than that in Chinese men. The method to accurately calculate the peak BMD and the corresponding age was given. The peak BMD and age for Chinese men and women in radius were 0.7469 g/cm2 and 35 years old, and 0.7051 g/cm2 and 33 years old respectively. The peak BMD and age in ulna were 0.7515 g/cm2 and 35 years old for Chinese men, and 0.6904 g/cm2 and 31 years old for Chinese women. Peak BMD in Chinese women was lower than in men. Peak BMD occurred slightly earlier in Chinese women. We concluded that our model could successfully characterize the regularity of bone mass accumulation and loss during the whole lifetime. The quantitive relationship was very useful in the diagnosis of osteoporosis.

Adolescent↗