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Biomedical subjects

Y M Shi

Publications and source records attributed to Y M Shi.

At least 19 recordsLinked to original sources
PubMed2003

Fast repair of the poly G hydroxyl radical adduct by two phenylpropanoid glycosides.

The repair activities and the reaction mechanisms of two phenylpropanoid glycosides (PPGs), isolated from a herb used in Chinese folk medicine, towards the oxidizing hydroxyl radical adduct of poly G were studied with a pulse radiolytic technique. On pulse irradiation of a nitrous oxide saturated 4 mM aqueous solution of poly G containing one of the tested compounds, the transient absorption spectrum of the hydroxyl radical adduct of poly G decays with the formation of that of the phenoxyl radical of the tested compound within several tens microseconds after the electron pulse irradiation. The results indicated that there was a repair reaction between the hydroxyl radical adduct of poly G and the compounds tested. The rate constants for the repair reactions of poly G hydroxyl radical adducts by verbasicoside and cistanoside C were determined to be 1.4 and 1.0 x 10(9) M(-1) x s(-1), respectively.

Antioxidants↗
PubMed2003

Scavenging effects of natural phenols on oxidizing intermediates of peroxynitrite.

Most of peroxynitrite (ONOO-/ONOOH) is formed via the diffusion-limited reaction between nitric oxide and superoxide. In biological systems, the decomposition of ONOO- yields 30-35% of carbonate radical (CO3*-) and nitrogen dioxide (NO2*), which are strongly oxidizing intermediates and are suggested to take a part of the responsibility for the toxicity of nitric oxide (NO*) or ONOO-. Therefore, the current study focuses on the scavenging activities of phenols toward CO3*- and NO2* to protect biomolecules from damage caused by NO* or ONOO- using the technique of pulse radiolysis. From the build-up kinetic of the phenoxyl radicals and the decay kinetic of CO3*- radical, the rate constants of scavenging reactions were determined to be 1.9-3.4 x 10(8) M(-1) x s(-1) and 0.11-1.9 x 10(8) M(-1) x s(-1) for CO3*- and NO2* respectively. The results indicated that the tested phenols are the efficient scavengers of CO3*- and NO2*.

Carbonates↗
PubMed2001

[Clinical study on treatment of female idiopathic precocious puberty with combined therapy of Chinese medicine and megestrol acetate].

OBJECTIVE: To find effective therapeutic approach for treating true idiopathic precocious puberty suitable to our national condition and different from gonadotrophin releasing hormone agonist. METHODS: One hundred and six girls with idiopathic precocious puberty were divided into 3 groups. The 51 girls in the combination therapy group were treated with megestrol acetate (MA) and Chinese medicine for nourishing Yin and removing Fire, the 35 girls in the MA treated group were treated with MA alone and the other 20 girls were given no treatment at all as control. Luteinizing hormone releasing hormone (LHRH) stimulating test was performed before and after treatment, and size of uterus and ovary, linear growth rate, X-ray bone age measurement and final height prediction were also observed simultaneously. RESULTS: After being treated with combination therapy for 2.7 years in average, in the combination therapy group, the luteinizing hormone peak value of LHRH stimulating test was reduced from 48.5 +/- 37.1 IU/L to 12.2 +/- 9.3 IU/L (P < 0.001), size of uterus and ovary decreased, secondary sexual characteristics regressed, the bone age difference/chronological age difference value (delta BA/delta CA) reduced from 1.35 +/- 0.64 to 0.65 +/- 0.36(P < 0.001), and predictive final height increased from 153.3 +/- 3.6 cm to 158.5 +/- 4.3 cm (P < 0.001). CONCLUSION: Combination therapy could not only modulate the function of hypothalamic-pituitary-ovarian axis and the development of internal genitalia, but also could slow down skeletal growth, delay skeletal maturation, and thereby prevent premature epiphyseal fusion and increase the final height of patients.

Child↗
PubMed2000

Effects of ascorbic acid and DL-alpha-tocopherol on human hepatoma cell proliferation and redifferentiation.

AIM: To examine the effects of ascorbic acid (AA) and DL-alpha-tocopherol (alpha T) on the proliferation and redifferentiation of human hepatoma cell. METHODS: Choosing an all-trans retinoic acid (RA) as a positive control, cell surface charge, biochemical changes, and cell growth in soft agar were measured. RESULTS: After treatment with AA 4 mmol.L-1 and alpha T 1 mmol.L-1 together, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 61.3%. The indices related to cell malignancy alleviated significantly; cell surface charge decreased, the electrophoresis rate dropped from 1.64 to 0.89 microns.s-1.V-1.cm-1, the average value of alpha-fetoprotein (alpha-FP) content decreased from 300 to 80 micrograms.g-1 (protein), and gamma-glutamyl-transpeptidase (gamma-GT) activity decreased from 0.81 to 0.201 U.g-1(protein). The index related to cell differentiation increased significantly, such as the average level of tyrosine-alpha-ketoglutarate transaminase activity increased from 10.6 to 45 micrograms.g-1 (protein), and the colonogenic potential decreased by 96.6%. CONCLUSION: AA and alpha T combination inhibited human hepatoma cell proliferation, induced redifferentiation, and reversed its malignant phenotypic characteristics.

Ascorbic Acid↗
PubMed1999

Effects of ascorbic acid on human hepatoma cell proliferation and redifferentiation.

AIM: To examine the effects of ascorbic acid (AA) on hepatoma. METHODS: Choosing an all-trans tretinoin (Tre) as a positive control, cell growth, and cell redifferentiation tests by cell surface charges, biochemical changes, and cell growth in soft agar were measured. RESULTS: After being treated with AA 6 mmol.L-1, the growth curve and mitotic index of human hepatoma cells decreased remarkably, the cellular growth inhibitory rate amounted to 58.9%. The indices related with cell malignancy alleviated, such as cell surface charge obviously decreased, the electrophoresis rate dropped from 1.64 microns.s-1.V-1.cm-1 to 0.93, the average value of alpha-fetoprotein (alpha-FP) content decreased from 302 micrograms.g-1(protein) to 90, and gamma-glytamyl-transpeptidase (gamma-GT) activity from 0.81 U.g-1(protein) to 0.16. The index related with cell differentiation increased, such as the average level of tyrosine-alpha-ketoglutarate transminase activity increased from 10.3 micromol.g-1(protein) to 41.2, and the colonogenic potential decreased 94.4%. CONCLUSION: AA can inhibit human hepatoma cells proliferation, induce redifferentiation, and reverse its malignant phenotypic characteristics.

Antineoplastic Agents↗
PubMed1998

Apoptosis, redifferentiation and arresting proliferation simultaneously triggered by oxidative stress in human hepatoma cells.

The effects of oxidative stress (ascorbic acid-ferrous system) on the proliferation, differentiation and apoptosis of the human hepatoma cell SMMC-7721 were studied. Oxidative stress significantly inhibited cell proliferation and induced morphological differentiation. Whatever the indices related with cell malignancy, such as alpha-fetoprotein and c-glutamyltranspeptidase or the index related with cell differentiation, such as tyrosine-alpha-ketoglutarate transaminase, all inclined evidently to normalization. The tumour's clonogenic potential decreased significantly. Moreover, together with differentiation, the phenomenon of apoptosis was found by the appearance of apoptotic bodies, detached cells, and apoptotic morphological feature. Although, their DNA was not degraded into oligonucleosomal fragmentation, the DNA was cut into larger fragments (about 21.2 kbp) of a size associated with chromatin loops. These findings indicated that oxidative stress can induce both differentiation and apoptosis simultaneously in tumour cells. All the results showed that oxidative stress may initiate the tumour cells reverse transformation. The possible mechanism of the differentiation and apoptosis induced by oxidative stress may be related to the lipid peroxidation of cell membrane.

Apoptosis↗
PubMed1996

[Clinical and experimental studies of zhenkeling oral liquor on treatment infantile cough].

One hundred and seventy children with cough were divied into two groups at random. 120 patient were treated with Zhenkeling oral liquor (ZKL group). The other 50 children were given pectoral syrup (control group). The results showed that the total effective rates of ZKL group and control group were 96.7% and 56.0% respectively, and the markedly effective rates were 80.8%, 18.0% respectively (P < 0.001). Animal experiments indicated Zhenkeling has the effect of relieving cough, reducing sputum and ameliorating asthma; their antibiotic and anti-inflammatory effects were discovered too. The dosage of Zhenkeling was 100 times as clinical dose in acute toxicity test and the dosage was 32, 16, 8 times as clinical dose in long term toxicity test respectively. No adverse action was found in these experiments.

Administration, Oral↗
PubMed1995

Anti-donor antibody class switching after liver transplantation.

The humoral immune response directed against donor antigens was monitored by flow cytometry in 17 liver transplant patients using donor leukocytes as targets. Overall, donor-specific antibodies developed in 15 patients; these included all 9 patients who had experienced a biopsy-proven episode of acute rejection and 6 out of 8 patients who had not had an acute episode of rejection. The isotypes of the donor-specific antibodies in the 9 patients who had experienced an early episode of acute rejection were IgG in 8 patients, IgE in 8 patients, and IgA in 6 patients; all 9 patients had IgE and/or IgA antibodies. In the 6 patients who showed no evidence of acute clinical rejection but nevertheless developed donor-specific antibodies, the isotype was IgM associated in 5 of them, with an immunoglobulin class switching to the IgG isotype; none of these patients had antibodies of the IgA or IgE isotype. These results indicate that the lack of rejection of a liver allograft does not necessarily result from a lack of immune response against donor antigens. Rather, the distinct pattern of (cytokine dependent) immunoglobulin class switching suggests that the lack of liver graft rejection may be the result of an immune activation pathway distinct from that resulting in graft rejection.

Adult↗
PubMed1994

Experimental study of chuanxiong on cerebrovascular hemodynamic parameters.

In the experimental rabbit arteriosclerosis, the change of the cerebrovascular hemodynamic parameters (CVHP) and the effect of Chuanxiong (CX) on CVHP were observed. In arteriosclerosis group (AS group), the mean flow (Qmean), mean velocity (Vmean), maximal velocity (Vmax) and minimal velocity (Vmin) of the carotid blood flow and cerebrovascular compliance for zero pressure (CO) were significantly decreased (P < 0.05, 0.01), but the values of cerebrovascular peripheral resistance (R) and characteristic impedance (Zc) were significantly increased (P < 0.05 and 0.01), and the value of R showed significant positive correlation with the extent of carotid lesions (P < 0.01). All indexes of CVHP of the Chuanxiong group (CX group) were close to and had no significant difference from those of the normal group (N group) but Qmean, Vmean, Vmin, CO and R were significantly better than those of the AS group (P < 0.05, 0.01). These results showed that CX can effectively improve cerebrovascular hemodynamics.

Animals↗
PubMed1993

[Experimental study of Ligusticum wallichii on cerebrovascular hemodynamic parameters].

The model of experimental atherosclerosis was established by means of dietary hyperlipidemia and repeated intravenous injection of heterologous serum to make the immunologic injuries of arterial endothelium, in which the effect of Ligusticum wallichii (LW) on the cerebrovascular hemodynamic parameters (CVHP) was observed. All CVHP indexes in LW group were near that of normal group, and there was no significant difference between these two groups. The carotid arteries' mean flow (Qmean), mean velocity (Vmean), maximal velocity (Vmax), cerebrovascular peripheral compliance for zero pressure and cerebrovascular peripheral resistance (R) in LW group were significantly better than that of atherosclerotic control group (P < 0.05-0.01). The results showed that LW had protective effects on cerebral vessels.

Animals↗
PubMed1992

[Long-term effect of Schonlein-Henoch nephritis with nephritic-nephrotic syndrome in children by traditional Chinese medicine and Western medicine].

21 cases are fully agreed with the diagnosis standard of Schonlein-Henoch nephritis. Biopsy on the kidney of 5 cases with resistant duration was made and all were diagnosed as mesenteric hyperplastic glomerular nephritis, among them, one with segmental sclerosis, one with segmental sclerosis and crescents in some glomerulus. 13 cases were treated with prednisone, cyclophosphamide and Traditional Chinese herbs. 8 cases with wilfordine adding and/or traditional Chinese herbs. The results showed that 15 of 21 cases were cured, one case perfect remission, 4 cases part remission. All of the cases were followed-up from 2 years and 10 months to 12 years and 4 months, average 7.34 years. The late results: Group A, 16 cases with symptom, physical exam, urine routine normal. Group B, 4 cases with microscopic hematuria and/or "a little-(+)" urinary protein. Group C, one case with "+2" urinary protein and/or hypertension, urinary creatinine clearance rate normal. Of 5 cases, whose biopsies of kidney were made, one with glomerular segmental sclerosis belonged to Group B. 13 of 21 cases had recurrence for 1-6 times, which was closed related with up respiratory tract infection.

Child↗
PubMed1991

Mechanism of action of arginine vasopressin on acute ischemic brain edema.

The purpose of this experiment is to study the role of arginine vasopressin (AVP) in acute cerebral ischemic edema in Mongolian gerbils. The results show that intracerebroventricular injection (ICV) of AVP exacerbates acute ischemic brain edema, while ICV of AVP antiserum significantly decreases the ischemic brain edema. Nimodipine (calcium antagonist) cannot block this role of AVP in brain edema. In addition, the cortical Na(+)-K+ ATPase activity is significantly decreased, while the cAMP content of ischemic cortex and hypothalamus and the cGMP content of the hypothalamus are markedly increased after AVP ICV. These suggest that AVP may play an important role in the pathophysiologic process of ischemic brain edema by inhibiting the Na(+)-K+ ATPase activity of the cerebral cell membrane and the AVP receptors mediated by cAMP and cGMP.

Animals↗
PubMed1991

Parkinson's disease in China. Coordinational Group of Neuroepidemiology, PLA.

An epidemiological study on the incidence and prevalence of Parkinson's disease (PD) was carried out in 29 provinces, cities and autonomous regions in this country in 1986. The survey was conducted in 117 areas, and 566 patients with PD were found among 3,869,162 persons examined, giving a point prevalence for men and women of 16.9/10(5) and 12.4/10(5), with the highest prevalence after the fifth decade of age. The disease was most prevalent in the southern part of China, especially in Hunan and Guangxi provinces. The incidence was 1.5/10(5)/yr in 1986. Both the prevalence and incidence of PD in China are lower than those in the white race and Japanese.

Adult↗
PubMed1991

[Exploring the substantial basis of the features yinxu huowang in girls with precocious puberty].

Differential diagnosis to 75 girls with true precocious puberty was made using method of TCM. It was observed that each girl had Yinxu Huowang (intense internal heat due to deficiency of vital essence) to a certain extent, these features were very remarkable in most of them. To explore the substantial basis of the features, the functions of hypothalamic-pituitary-ovarian axis were determined. The results showed that the levels of serum FSH, LH, E2 in the girls rise significantly than those in normal girls of the same age, and LHRH stimulating test displays characteristic changes of excessive activity. Treated with TCM of Ziyin Xiehuo, (nourish vital essence reducing intense internal heat) and remitted, the levels of serum FSH, LH, E2 descend significantly, the volume of uterus and ovary reduce markedly, secondary sexual characteristics retrogress evidently, while the features of intense internal heat due to deficiency of vital essence mitigate obviously. According to the above mentioned, the authors consider that the hypothalamic-pituitary-ovarian axis starting beforehand and being hyperfunction are likely to be the substantial basis of the features--that deficiency of Shen Yin, (vital essence) accompanied with intense Fire of the Vital Gate--of the girls with true precocious puberty.

Child↗
PubMed1991

[Idiopathic thrombocytopenic purpura in children treated with replenishing qi and tonifying kidney and the changes in thrombocyte aggregative function].

UNLABELLED: Forty-one children with idiopathic thrombocytopenic purpura (ITP) were reported in this paper. Of all, 36 with petechia and ecchymosis, 28 with nasal hemorrhage, 5 with hematochezia and 1 with subcutaneous hematoma. According to the TCM differentiation, 24 and 17 of all belonged to the type of impairment of Yin due to blood-heat and both deficiencies of Qi and tonifying Kidney and its basic prescriptions were: dried Radix Rehmanniae, Radix Angelicae Sinensis, Radix Paeoniae Rubra, Radix Rubiae, Fructus Psoraleae, stir-frying Radix Astragali, Semen Cuscutae, Caulis Spatholob; Chinese Jujubae, Radix et Rhizoma Rhei. The average treating duration was 5.02 months. RESULTS: 24 cases cured, 6 recovered, 10 improved, 1 failed, with a total effective rate of 97.6%. 22 of the cured were followed-up without recurrence in average 10.4 months after withdrawal. In 32 cases, the thrombocyte aggregative function was tested with ADP induction, meanwhile in 20 of 32 cases aggregation with adrenaline induction was tested. The results before and after treatment showed an evident difference, with low function before treatment and normal after treatment. It is concluded that the replenishing Qi and tonifying Kidney may have a better effect on both acute and chronic children ITP without recurrence after withdrawal.

Child↗
PubMed1990

[Observation on polytene chromosomes of the ovarian nurse cell of Anopheles minimus from Guangxi].

The ovarian nurse cell's polytene chromosomes of An. minimus exist as 5 arms, the telocentric X chromosome, the submetacentric chromosome 2 and the metacentric chromosome 3. The X chromosome is easily recognized by its length and shuttle-shaped zone 6. The most important characteristics is that each autosome arm has one to three big puffs. Among the 46 zones, 7A, B and 19C in 2R which is the longest arm in the complement, 28A and 20A, B in 2L, 30A, B and 37D in 3R and 46D and 38A, B in 3L are considered as characteristic zones. It is proposed that this map might be considered as the "standard" map of the ovarian nurse cell's polytene chromosomes for An. minimus from Guangxi.

Animals↗