Biomedical subjects

Ying Huang

Publications and source records attributed to Ying Huang.

210 records · Page 12Linked to original sources

PubMed2001

MEMS-based sample preparation for molecular diagnostics.

Completion of the Human Genome Project is driving the rapid development of molecular diagnostics in the laboratory. To accelerate the penetration of genetic tests and other nucleic acid-based tests into clinical markets, simple, compact, automatic sample-preparation systems for molecular diagnostics must be developed. Microelectromechanical systems (MEMS) is a promising approach for the development of automated sample preparation for the clinical laboratory or point-of-care setting. This review discusses MEMS-based components that could be applied to the different stages of the sample-preparation process such as cell separation, nucleic acid purification, and nucleic acid amplification. Examples of functional component integration are given. Issues discussed include partitioning of functions between the instrument and disposable unit, methods of propulsion of fluids and particles, vapor and liquid barriers, and sample size. Although further evaluation and development are needed to provide practical solutions to some of these issues, we conclude that MEMS-based components might contribute to some components in a sample-preparation system consisting of modular instruments and disposable units, but will not provide a generic or a totally integrated solution.

DNA, Bacterial↗

PubMed2001

Therapeutic Effects of rhIL-11 on Irradiation-Induced Myelosuppression in Rhesus Monkeys.

The efficacy of rhIL-11 in treating thrombocytopenia and neutropenia in gamma-irradiated rhesus monkeys and the variation in curative effect due to difference of administration times were studied. Healthy rhesus monkeys were exposed to 3.0 Gy (60)Co total body irradiation (TBI) to result in pancytopenia for three weeks. Treatment with rhIL-11 (30, 60 or 120 micro g.kg(-1).day(-1)) on early days (days 0 - 13 after TBI) could significantly improve the nadir of platelet count. Although the nadir of leukocyte count was not improved, the duration below 50% of its baseline value was shortened similarly to that of platelet. During the first two weeks after TBI, erythrocyte numbers of the animals treated with these doses of rhIL-11 were lower than those of the control group at first but they became higher beginning from the third week. Four monkeys were treated with rhIL-11 at 60 micro g.kg(-1).day(-1) on days 13 - 26 after TBI. The numbers of their peripheral blood cells followed the similar decrease patterns as those of control group during the first three weeks, then they were improved rapidly. By semi-solid bone marrow cell culture it was demonstrated that rhIL-11 could stimulate bone marrow cells to form more CFU-Meg, CFU-Mix, CFU-E, BFU-E and CFU-GM in vitro. Histopathological observation revealed that bone marrow of the control group was devoid of hematopoietic cells and bleeding, being contrary to that of the group treated with rhIL-11, in which the cells proliferated actively. The results suggest that rhIL-11 can accelerate hematopoietic recovery of irradiated monkeys.

Journal Article↗

PubMed2000

Exogenous p21(WAF1) Transfection Affects Apoptosis in Human Fibroblasts.

pDOR-p21 sense and pDOR-p21 antisense retroviral expression vectors were constructed and successfully transfected by Lipofectin into normal human diploid fibroblasts(2BS line), resulting in 2BS-p21s and 2BS-p21a cell lines, respectively. Southern blot analysis verified that the exogenous p21(WAF1) cDNA were integrated into genomic DNA. Compared with the cells transfected with pDOR-neo empty vector, p21(WAF1) mRNA expression increased in 2BS-p21s cells, which were less sensitive to apoptosis induced by NaBu, and showed higher cell viability, delayed appearance of DNA ladder, and less area of apoptosis peak. On the other hand, p21(WAF1) mRNA expression decreased in 2BS-p21a cells, which were more sensitive to apoptosis induced by NaBu. These results indicated that the expression amount of p21(WAF1) in 2BS cells was negatively related with its susceptibility to apoptosis induced by NaBu.

Journal Article↗

PubMedDate not supplied

Chemiluminescence microflow injection analysis system on a chip for the determination of uric acid without enzyme.

A new microflow injection analysis (microFIA) system on a chip coupled with chemiluminescence (CL) for the non-enzymatic determination of uric acid is described. The microFIA system produced by using two transparent poly(methylmethacrylate) (PMMA) chips measured 50 x 40 x 5 mm, the microchannels, etched by CO2 laser, were 200 microm wide and 100 microm deep, and the volume of the reaction area (RA) was about 1.2 microL. The injection pump, with accurate time control, monitored all reagents, including the sample. The uric acid was sensed by the chemiluminescence reaction between luminol and ferricyanide. The linear range of the uric acid concentration was 0.8-30 mg/L and the detection limit was 0.5 mg/L (S/N = 3). The relative standard deviation was 4.42% for 5 mg/L uric acid (n = 8). The proposed method has been successfully applied to the non-separation determination of uric acid in human serum and urine.

Ferricyanides↗

PubMedDate not supplied

Androgen-induced prostate-specific antigen gene expression is mediated via dihydrotestosterone in LNCaP cells.

Prostate cancer is a leading cause of cancer death in American males. Androgens play an essential role in prostate development, growth and pathogenesis of benign prostate hyperplasia, and prostate cancer. Although testosterone is the main androgen secreted from the testes, dihydrotestosterone (DHT), a more potent androgen converted from testosterone by 5alpha-reductase isozymes, type 1 and 2, is the major androgen in the prostate cells. Thus, 5alpha-reductase(s) are critical in determining androgen activity in the prostate. However, it is unclear in prostate tumor cells whether 1 or 2 5alpha-reductase isozymes are expressed and whether they are functionally important. In the present report, we studied the importance of 5alpha-reductase isozymes in the androgen induction of prostate-specific antigen (PSA) gene expression in LNCaP prostatic tumor cells. Treatment with either testosterone or DHT in LNCaP cells produced dose- and time-dependent increases in PSA levels in the cell media and in PSA messenger RNA (mRNA) levels in the cells. However, testosterone-induced but not DHT-induced PSA gene expression was significantly inhibited by finasteride, a 5alpha-reductase inhibitor, in a dose-dependent manner. Furthermore, we demonstrated for the first time that both 5alpha-reductase-1 and 5alpha-reductase-2 mRNAs were expressed in LNCaP cells using reverse transcriptase-polymerase chain reaction (RT-PCR) and RT-PCR Southern blot analysis. These results suggest that both 5alpha-reductase isozymes are present and functionally important in prostatic tumor LNCaP cells and that DHT is a major mediator of androgen induction of PSA gene expression in these cells.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗

PubMedDate not supplied

Characterisation of new oligoglycosidic compounds in two Chinese medicinal herbs.

A series of caffeic acid derivatives (3,5-dicaffeoyl-quinic acid, 3,4-dicaffeoyl-quinic acid, and 4,5-dicaffeoyl-quinic acid), and the new compound beta,3,4-trihydroxyphenethyl-O-[beta-apiofuranosyl-(1-->4)-alpha- rhamnopyranosyl-(1-->3)]-(4-O-caffeoyl)-beta-glucopyranoside (wedelosin), as well as three known flavonoid glycosides (quercetin 3-O-beta-glucoside, kaempferol 3-O-beta-apiosyl-(1-2)-beta-glucoside, and astragalin or kaempferol 3-O-beta-glucoside) were isolated from the Chinese medicinal herb Wedelia chinensis. Wedelosin showed an inhibitory activity on both the classical and the alternative activation pathway of the complement system. Another Chinese medicinal herb, Kyllinga brevifolia, yielded two known flavonoid glycosides [kaempferol 3-O-beta-apiosyl-(1-2)-beta-glucoside and isorhamnetin 3-O-beta-apiosyl-(1-2)-beta-glucoside], and a new quercetin triglycoside [quercetin 3-O-beta-apiofuranosyl-(1-->2)-beta-glucopyranoside 7-O-alpha-rhamnopyranoside]. The latter compound showed a moderate anti-viral activity.

Antiviral Agents↗

PubMedDate not supplied

Regulation of recombinant monoclonal antibody production in chinese hamster ovary cells: a comparative study of gene copy number, mRNA level, and protein expression.

We performed a comparative analysis on CHO cells with varying recombinant monoclonal antibody production rates (qAb) and investigated the regulation of MAb production. Two families of CHO cells each composed of one parental and two progeny cell lines, generated by stepwise increases in methotrexate (MTX) concentration, were studied. The MAb heavy chain (HC) and light (LC) gene copy numbers and mRNA levels were quantitated by Southern and northern blotting in midexponential growth phase. We observed 2- to 3-fold amplification in gene copy numbers in high producing cell lines when compared with parental cell lines. However, the mRNA levels in the high producers were 5- to 7-fold higher, correlating well with the 5- to 7-fold increase in qAb. These results were confirmed by real-time qPCR analysis. Our study reveals that the MTX-mediated MAb overexpression results from both an increase in the gene copy number and more efficient transcription of each gene copy. We also observed that the HC to LC gene copy ratio may affect the protein yield in MAb expression systems.

Animals↗

PubMedDate not supplied

Receptor isoform and ligand-specific modulation of dihydrotestosterone-induced prostate specific antigen gene expression and prostate tumor cell growth by estrogens.

Androgens via the androgen receptor (AR) play crucial roles in prostate physiology and pathophysiology. These androgen actions can be either inhibited or potentiated by estrogens. The mechanisms of these seemingly opposing estrogen effects are unclear. We studied the effects of estrogens on the modulation of androgen induction of prostate specific antigen (PSA) gene expression and prostate tumor cell growth. Cotransfection analyses in CV-1, DU-145, and PC-3 cells showed that dihydrotestosterone (DHT)-induced PSA transcription activity was inhibited by 17beta-estradiol, diethylstilbestrol, ICI182780, and 17alpha-estradiol, but not by tamoxifen via estrogen receptor alpha (ERalpha). In the presence of ERbeta, 17beta-estradiol and diethylstilbestrol had no significant effect, while 17alpha-estradiol inhibited and ICI182780 and tamoxifen potentiated DHT action. When both ERalpha and ERbeta were present, all ER-ligands except tamoxifen inhibited DHT action. The inhibition of DHT action by 17beta-estradiol via ERalpha was mainly dependent on the DNA binding domain, while the 17alpha-estradiol effect was mainly dependent on the ERalpha carboxyl terminus. Treatment with DHT in LAPC-4 prostate tumor cells that express a wild-type AR and both ERbeta and ERalpha greatly increased the PSA gene expression and cell growth. These DHT effects were significantly attenuated by the addition of 17alpha-estradiol, 17beta-estradiol, or cyproterone acetate in a dose-dependent manner. These results indicate that estrogens produce an ER-isoform- and ER-ligand-specific modulation of DHT induction of PSA gene expression and prostate tumor cell growth, providing a molecular basis for designing favorable agents for the prevention and control of prostate cancer.

Animals↗

PubMedDate not supplied

Death receptor 5 regulation during selenium-mediated apoptosis in human prostate cancer cells.

Selenium is an essential micronutrient that is currently being tested for prostate cancer chemoprevention. In spite of its significant promise as a chemopreventive agent, the molecular mechanisms of selenium-mediated effects remain to be elucidated. Recent evidence suggests that selenium may mediate its chemopreventive effects by inducing apoptosis in human prostate cancer cells. Here we report that selenium-mediated apoptosis appears to involve membrane death receptor, DR5-dependent pathway in human prostate cancer cells. Selenium specifically upregulated DR5 expression but not that of DR4. Selenium upregulation of DR5 was coupled with caspase 8 activation and Bid cleavage thereby suggesting the existence of a potential cross-talk between the DR5 and the mitochondrial pathways. Thus, our results suggest that DR5 is specifically regulated by selenium and its activation may play an important role in selenium-mediated chemoprevention.

Antioxidants↗

PubMedDate not supplied

The FADD is going nuclear.

Fas-associated death domain protein (FADD) is an adaptor molecule that bridges the interactions between membrane death receptors and initiator caspases. Thus, the site of its action has always been expected to be the cytoplasmic death-inducing signaling complex (DISC). Recent evidence indicates that FADD primarily resides in the nucleus and appears to shuttle between nucleus and cytoplasm. In addition to its well-established role in transduction of apoptotic signals, FADD may also play a role in regulating genome surveillance and perhaps in other as yet unidentified cellular processes.

Active Transport, Cell Nucleus↗

PubMedDate not supplied

The Chinese medicinal herbal formula ZYD88 inhibits cell growth and promotes cell apoptosis in prostatic tumor cells.

Prostate cancer is a leading cause of cancer death in American males. Currently, there is no curative therapy available once prostate cancer has metastasized. A major systemic therapy for metastatic prostate cancer is anti-androgen therapy. Unfortunately this therapy is only palliative and rarely curative, and eventually the tumor cells develop resistance to further hormone manipulation. It is therefore imperative to develop alternative effective therapies. In the present study, the effect of a Chinese herbal formula, ZYD88, on regulation of cell growth and cell apoptosis was examined in prostatic tumor cells. ZYD88 decreased cell viability of multiple prostatic tumor cell lines, DU-145, PC-3, MDA-PCa 2b and LNCaP in a time- and dose-dependent manner. It also produced a rapid and dose-dependent increase in caspase 3 activity in LNCaP and PC-3 cells, and induced DNA fragmentation in LNCaP cells, indicating cell apoptosis. In cotransfection assays, ZYD88 inhibited androgen-induced prostate specific antigen (PSA) gene promoter activity, and induced estrogen-target gene promoter activity. These data suggest that ZYD88 is a potential agent for prostate cancer therapy, and deserves further study.

Apoptosis↗

PubMedDate not supplied

Death receptor activation complexes: it takes two to activate TNF receptor 1.

The extrinsic pathway of apoptosis originates at the membrane and engages membrane death receptors. Tumor necrosis factor receptor 1 (TNF-R1) is a death receptor that transduces both the death and survival signals but the molecular mechanisms via which TNF-R1 mediates these signals remain poorly understood. Recently, it has been reported that the TNF-R1 transduces these signals via two signaling complexes. The first complex (complex I) is formed at the membrane by TNF-R1, TRADD, RIP, TRAF2 and c-IAP1, while the second complex (complex II), formed in the cytosol, predominantly contains FADD and pro-caspases 8/10 but lacks TNF-R1. Complex I is responsible for activating NF-kappaB and thus, the transduction of survival signals. Complex II, on the other hand, is reported to transduce the apoptotic signals and it does so only if NF-kappaB is unable to promote upregulation of the anti-apoptotic FLIPL. These findings highlighting the complexities of TNF-R1-mediated signaling events are likely to further the progress in the constantly evolving area of death receptor-dependent signaling pathways.

Antigens, CD↗