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Biomedical subjects

Y X Ma

Publications and source records attributed to Y X Ma.

At least 37 records · Page 2Linked to original sources
PubMed1998

BRCA1 as a potential human prostate tumor suppressor: modulation of proliferation, damage responses and expression of cell regulatory proteins.

In addition to breast and ovarian cancer in women, recent evidence suggests that germ-line mutations of the breast cancer susceptibility gene-1 (BRCA1) also confer an increased life-time risk for prostate cancer in male probands. However, it is not known if and how BRCA1 functions in prostate cancer. We stably expressed wild-type (wt) and tumor-associated mutant BRCA1 transgenes in DU-145, a human prostate cancer cell line with low endogenous expression of BRCA1. As compared with parental cells and vector transfected clones, wtBRCA1 clones exhibited: (1) a slightly decreased proliferation rate (doubling time = 25 h as compared with 22 h for control cells); (2) a (3-6)-fold increase in sensitivity to chemotherapy drugs (adriamycin, camptothecin, and taxol); (3) increased susceptibility to drug-induced apoptosis; (4) reduced repair of single-strand DNA strand breaks; and (5) alterations in expression of key cellular regulatory proteins (including BRCA2, p300, Mdm-2, p21(WAF1/CIP1), Bcl-2 and Bax). Clones transfected with the 5677insA breast cancer-associated mutant BRCA1 (insBRCA1) displayed a similar phenotype to wtBRCA1 clones, except that insBRCA1 clones had a significantly decreased proliferation rate (doubling time = 42 h). On the other hand, cells transfected with with 185delAG mutant BRCA1 showed no obvious phenotype as compared with parental or vector transfected cells. These findings suggest that BRCA1 may function as a human prostate tumor suppressor by virtue of its ability to modulate proliferation and various components of the cellular damage response. They also suggest several potential target gene products for a BRCA1 prostate tumor suppressor function.

Antineoplastic Agents↗
PubMed1998

Survival of Taenia solium cysticerci in carcasses of pigs kept at 4 C.

In the present study, the survival of cysticerci of Taenia solium in carcasses of 1 Small-Ear-Miniature and 2 Landrace Small-Ear-Miniature pigs kept in a refrigerator at 4 C was determined. The viability of the cysticerci was determined by observing evagination and active movement of the scolex under a fluorescent light after digestion in pig bile. Although no viable cysticerci were found after day 30, 58.8% cysticerci survived between day 26 and day 30. Moreover, more than 80% of the cysticerci were viable between day 1 and day 25. These findings indicate that taeniasis solium can be transmitted through eating raw or undercooked pork or viscera of pigs following refrigeration at 4 C for less than 30 days.

Animals↗
PubMed1997

A comparative study on egg hatching methods and oncosphere viability determination for Taenia solium eggs.

The efficiencies of an enzyme method and the sodium hypochlorite method in hatching eggs of Taenia solium (Henan strain) were compared. The viability of the hatched oncospheres was determined by staining with trypan blue. For the former method, the hatching rate and viability percentage were 85.7% and 79.7%, respectively. The corresponding figures for the latter method were 97.9% and 86.7%, respectively. These findings indicate that the sodium hypochlorite method is a simple, efficient and practical method for hatching eggs of Taenia solium.

Animals↗
PubMed1997

HLA and longevity or aging among Shanghai Chinese.

Twenty-two centenarians and one hundred and seventy-nine nonagenarians (mean age 93 +/- 1.04 years) in the Shanghai Region of China were phenotyped for alleles of A (13 types), B (21 types) and C (6 types) loci of the human leukocyte antigen (HLA). The frequencies of HLA antigens were compared with 211 healthy adults whose ages ranged from 20 to 50 years. It was observed that A9 was highly associated with longevity (frequency in the longevity group is 38%, the control group 24%, P = 0.002). A30 showed marked inverse correlation (frequency in the longevity group is 8%, the control group 17%, P = 0.008). Cw3, Cw6 and Cw7 were also inversely correlated (P = 0.02, 0.04 and 0.02, respectively). Thus, it is likely that A9 may contribute to longevity while A30, Cw3, Cw6 and Cw7 may be associated with aging. The average superoxide dismutase (SOD) contents of erythrocytes in 48 cases with the HLA-A9 (without A30) antigen in the longevity group and in 13 cases with the HLA-A30 (without A9) antigen in the control group were 555 +/- 96 and 593 +/- 58 micrograms/gHb, respectively (t = 1.375, P > 0.05).

Adult↗
PubMed1997

Physiological basis for long life span.

A collection of clinical data is reported on nonagenarians in comparison to an 'average' population of younger age. The results of these clinical data indicated that a vital physiological basis for long life span probably existed. The basis include a better micro-blood-flow state, a better cardiac, immune (nature killer cell activity), adrenocortical, hepatic and renal function, and a higher level of high density lipoprotein cholesterol. It is suggested that the method, including Chinese traditional medicine, to improve the micro-blood-flow, nature killer cell activity, high density lipoprotein cholesterol and vital organ function may be beneficial for life preservation and aging retarding.

Aged↗
PubMed1997

The aging retarding effect of 'Long-Life CiLi'.

'Long-Life CiLi' ('CiLi') oral liquid, is composed of superoxide dismutase (SOD), polysacchairide, vitamin C, vitamin E and trace elements which were all extracted from a natural plant fruit Cili (Rosa roxburghii Tratt) in Guizhou, China. A set of indices were evaluated after administration of 'CiLi' 10 ml Bid, for two months in 50-75 years old healthy people, the mean value of NK cell activity (22.4 +/- 10.8-->27.5 +/- 12.9%, P < 0.05), SOD (453.0 +/- 24.2-->468.6 +/- 21.3 micrograms/gHb, P < 0.001), Catalase (15.5 +/- 1.7-->17.4 +/- 3.0 U/mgHb, P < 0.001) and GSH content (2.3 +/- 0.3-->2.6 +/- 0.5 mg/gHb, P < 0.001) in erythrocytes and 'delta CO, CI, SV, SI, LVET, LVETI and AC' values increased significantly, while the serum LPO level (4.20 +/- 0.78-->3.78 +/- 0.50 nmol/ml, P < 0.001), total microcirculation weighed value (1.87 +/- 1.0-->0.92 +/- 0.5, P < 0.001), delta PVR (-241.7 +/- 733.2-->187.9 +/- 938.2, P < 0.05) and the light reaction time (Simple RT, red light: 383 +/- 128-->332 +/- 68.9 ms, P < 0.05; selective RT: red light 709 +/- 287-->566 +/- 119 ms, P < 0.05; green light 639 +/- 162-->536 +/- 80 ms, P < 0.01) decreased significantly. There were no significant differences in the control group. The mean life span of fruit flies were significantly elongated for low, medium and high concentrations 'CiLi' treatment groups than in the control group (Female: 57.6 +/- 11.3-->62.1 +/- 12.8; 69.6 +/- 14.7; 62.6 +/- 12 days; P < 0.05 approximately 0.001. Male: 56.3 +/- 9.6-->64.9 +/- 12.4; 64.5 +/- 14.5; 64.8 +/- 14.1 days, P < 0.001). It is suggested that 'CiLi' has an aging retarding and geroprotection effect.

Aged↗
PubMed1997

Effects of alanyl-glutamine on intestinal adaptation and bacterial translocation in rats after 60% intestinal resection.

The effects of alanyl-glutamine dipeptide (Ala-Gln)-enriched parenteral nutrition on intestinal mucosa and gut barrier function were investigated. Wistar rats were studied. After moderate surgical stress was induced by 60% resection of the small intestine, the rats were randomized to three groups: the chow group was given standard rat chow; the PN group received standard parenteral nutrition (PN); and the Ala-Gln group received glutamine dipeptide-enriched parenteral nutrition (3% Ala-Gln). Rats were maintained on their respective diets for 8 days. The chow and Ala-Gln groups maintained serum glutamine concentrations, intestinal mucosal thickness and villus height. Bacterial translocation rates in the chow and Ala-Gln groups were 20%, which was significantly less than that in the PN group (70%, P < 0.05). The results indicated that Ala-Gln-enriched parenteral nutrition maintains intestinal adaptation and gut barrier function after massive intestinal resection and parenteral nutrition.

Journal Article↗
PubMed1994

Effects of amrinone on cardiac contraction and relaxation in isolated, perfused rat heart.

The effects of amrinone on cardiac contraction and relaxation were assessed in isolated, perfused rat hearts. It was found that the left ventricular developed pressure (LVDP), dp/dtmax and -da/dtmax did not significantly increase, and the time constant (tau) did not markedly shorten with perfusion of low concentration (1 nmol/L, 100 nmol/L) of amrinone. The perfusion with higher concentration (1000 nmol/L) of amrinone reduced LVDP (P < 0.01), dp/dtmax (P < 0.01), -dp/dtmax (P < 0.01), and prolonged tau (P < 0.05) significantly. It was assumed that amrinone has no direct positive inotropic effect, and can not improve cardiac relaxation. On the contrary, the cardiac contraction and relaxation will be inhibited at higher concentration of amrinone.

Amrinone↗
PubMed1994

Effects of isoprenaline, phenylephrine on heart and influence of nifedipine on these effects.

In a perfused isovolumetrically contracting rat heart model, the effects of isoprenaline (IPN) and phenylephrine (PE) on myocardial contraction and relaxation were investigated, and the influence of nifedipine on these effects was studied. Both IPN and PE increased the myocardial contraction and improved its relaxation, but some differences existed. Nifedipine (10 nmol/L) substantially inhibited the PE-mediated inotropic effect, but in case of IPN-mediated inotropic ones, it did not. It was assumed that there may be various types of slow channels, one was activated by IPN, and the other, by PE.

Animals↗
PubMed1993

[Experimental study on effect of jiawei yupingfeng san on microcirculation and plasma superoxide dismutase activity in old mice].

The effects of Jiawei Yupingfeng San on microcirculation and plasma SOD of old mice were observed. The results showed that the prescription could markedly improve old mice's blood flow of microcirculation, increase their speed of blood flow and raise their plasma TSOD and Cu, Zn-SOD activity, and there was very significant difference compared with control (P < 0.001). The results suggested that this prescription had the effects of improving the quality of life and delaying the aging of organism.

Aging↗
PubMed1992

[Changes in T lymphocytes and their subpopulations and IgG in peripheral blood from mice infected with Trichinella spiralis].

Acid alpha-naphthyl esterase (ANAE), a cytoplasmic marker, was used to identify the T lymphocytes and their subpopulations in peripheral blood of mice infected with Trichinella spiralis, and Dot-ELISA was used to identify the serum IgG antibody of the infected mice. The results showed that T lymphocytes increased on the d3 after infection, reaching the peak on d14, and then remained in number greater than normal up to d77. The spotted granular ANAE positive cells (Help T cells, Th) decreased and the scattered granular ANAE positive cells (Suppressor T cells, Ts) increased, leading to a drop of the Th/Ts ratio. The reduction in host immune function during T. spiralis infection might be related to the drop of Th/Ts ratio. At the same time, the serum IgG antibody increased on d7 after infection, reaching the peak on d28, and remained higher up to d140. The results indicated that the host's cellular immunological level was lower while the host's IgG antibody level was higher during T. spiralis infection.

Animals↗
PubMed1991

Synthesis and biochemical studies of dithioate DNA.

Dithioate DNA was synthesized and used for various biochemical studies. Results from these studies indicate that dithioate DNA is a potent inhibitor of HIV Reverse Transcriptase, activates endogenous RNase H in HeLa cell nuclear extracts, and is a useful probe for studying protein-DNA interactions.

Base Sequence↗
PubMed1991

[Drug evaluation of huperzine A in the treatment of senile memory disorders].

Huperzine A is an alkaloid which was first isolated from Huperzia serrata (Thumb) Trev by Zhejiang Academy of Medical Sciences and Shanghai Institute of Materia Medica, Chinese Academy of Sciences. It exhibits a significant anticholinesterase activity and has been used on myasthenia gravis patients. The therapeutic effects were studied by random, match and double-blind method on 56 patients of multi-infarct dementia or senile dementia and 104 patients of senile and presenile simple memory disorders. The curative effects were evaluated by Wechsler memory scale. The im dose for multi-infarct dementia was 0.05 mg bid for 4 wk, whereas that for senile and presenile simple memory disorders was 0.03 mg bid for 2 wk. Saline was used on control group. The result showed that the curative effect of huperzine A was significant. Only a few patients felt slight dizziness and this did not affect the therapeutic effects.

Aged↗
PubMed1989

Prolonged hemopoiesis of murine bone marrow derived epithelioid cells in vitro.

We previously reported the isolation of a murine bone marrow derived stromal cell line, TC-1, and two sublines derived from this line. The monolayer of one subline, TC-1-C-3, directly supported the growth of nonadherent marrow cells in Dexter culture system for eight weeks. We report here the mechanism of the stromal cell effect on hemopoiesis in a long-term bone marrow culture system. When the hemopoietic blasts attach to the TC-1-C-3 cells, they are surrounded by the stromal cell cytoplasm within two hours and develop into cell clusters in a week. The developing hemopoietic cells show cell differentiation towards the granulocytic lineage. A key function of the epithelioid stromal cell, then, is to provide a 'niche' or 'envelope' for stem cells which supports long-term hemopoiesis in the Dexter culture system.

Animals↗
PubMed1989

[Observations on the anti-aging, antihypertensive and antihyperlipemic effect of Apocynum venetum leaf extract].

The effect of Apocynum venetum leaf extract on hypertension, hyperlipemia, SOD content of erythrocyte, platelet aggregation rate, pulse wave transmission time (RP interval) and human diploid cell was studied to evaluate if it has some anti-aging effects. The mean BP in 60 cases of the treated group decreased from 171 +/- 19/98 +/- 11 mmHg to 154 +/- 22/91 +/- 10 mmHg and 148 +/- 17/89 +/- 10 mmHg after treatment for 4 and 8 weeks (P less than 0.01). The HDL-C in 40 cases of hyperlipemia increased from 47.5 +/- 13 mg% to 63.9 +/- 18 mg% (P less than 0.01). These results were better than those in the control groups. delta RPF was lengthened from 10.1 +/- 6.0 ms to 15.3 +/- 7.3 ms, which indicated that the cardiac performance was improved. No significant change of platelet aggregation rate was obtained after 5-8 weeks treatment. The retarding effect on cell aging was observed by the morphologic changes of nucleus and the increase of subcultivation from 77 to 80 generations. SOD content of erythrocyte was significantly increased from 546.1 +/- 51 micrograms/gHb to 574.6 +/- 42 micrograms/gHb in 20 cases. So Apocynum venetum leaf extract might have some anti-aging effects.

Aged↗
PubMed1988

Immunohistochemical identification of exocrine and neuroendocrine subsets of large cell lung carcinomas.

Formalin fixed, paraffin embedded sections of 52 cases of pulmonary large cell undifferentiated carcinoma (LCUC) as defined in the current WHO classification were studied immunohistochemically to assess features of exocrine and neuroendocrine (NE) differentiation. Monoclonal antibody 44-3A6 was applied to detect a membrane association protein related to exocrine differentiation. A panel of ten neuroendocrine markers including antibodies to synaptophysin, chromogranin A, serotonin, and seven neuropeptides was used to assess NE differentiation. The broad spectrum anticytokeratin antibody PKK1 was used to confirm the epithelial differentiation of these tumors. Exocrine differentiation was detected in 40/52 (77%) of surgically resected LCUC, despite the absence of recognizable glands by light microscopy. Eighteen of 52 (35%) LCUC exhibited NE differentiation; synaptophysin was the most frequently detected NE marker. Cytokeratin immunostaining with PKK1 was demonstrated in 41/52 (79%) cases. Subsets of LCUC were defined based on their expression of exocrine or NE phenotypic markers. Accordingly, 28/52 (54%) LCUC displayed an exocrine phenotype, 6/52 (12%) a NE phenotype, 12/52 (23%) had combined exocrine and NE phenotypes, and 6/52 (12%) exhibited neither phenotype. In this surgical series, there were no significant differences in stage at presentation for the four subsets. Interestingly, two year survival appeared decreased in patients with tumors displaying the "pure" NE phenotype.

Biomarkers, Tumor↗