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Biomedical subjects

Y Hao

Publications and source records attributed to Y Hao.

At least 19 recordsLinked to original sources
PubMed2007

Morphologic and histologic comparisons between in vivo and nuclear transfer derived porcine embryos.

Nuclear transfer (NT) is an inefficient but invaluable tool of the biotechnology industry. This study looked at abnormalities associated with peri-implantation NT porcine embryos. Four experimental groups were examined: nonpregnant animals, in vivo pregnant animals, NT recipients, and manipulation control embryos (MC). Embryos (Day 10, 12, or 14) were evaluated for embryonic disc diameter, gross morphology, nucleoli density, and mitotic figure index. Day 12 (P < or = 0.03) and Day 14 (P < or = 0.01) NT embryos had increased numbers of nucleoli, and Day 14 NT embryos had an increased (P < or = 0.03) mitotic index compared to in vivo and MC embryos. In vivo produced Day 14 embryos had increased (P < or = 0.01) disk diameters when compared to other embryos except for MC Day 14, which also showed increases (P < or = 0.01) in disk diameter except when compared to in vivo produced Day 12 and Day 14 embryos. In vivo produced Day 12 had greater (P < or = 0.03) disk diameters when compared to NT and MC embryos except for MC Day 14, and in vivo produced Day 14 embryos, which had a significantly increased (P < or = 0.01) disk diameter. In vivo produced Day 14 embryos were morphologically more advanced (P < or = 0.01) than Day 14 NT and MC counterparts. NT embryos develop at a slower rate than their in vivo produced counterparts. The increase in nucleoli and mitotic index of NT embryos suggest the cell cycle may be affected or the NT embryos are employing other means to compensate for slow development. The techniques used during NT also appear to compromise embryo development.

Animals↗
PubMed2005

Direct binding of estradiol enhances Slack (sequence like a calcium-activated potassium channel) channels' activity.

17Beta-estradiol (E2) is a major neuroregulator, exerting both genomic and non-genomic actions. E2 regulation of Slack (sequence like a calcium-activated potassium channel) potassium channels has not been identified in the CNS. We demonstrate E2-induced activation of Slack channels, which display a unitary conductance of about 60 pS, are inhibited by intracellular calcium, and are abundantly expressed in the nervous system. In lipid bilayers derived from rat cortical neuronal membranes, E2 increases Slack open probability and appears to decrease channel inactivation. Additionally, E2 binds to the Slack channel and activates outward currents in human embryonic kidney-293 cells that express Slack channels but not classical estrogen receptors (i.e. ERalpha or ERbeta). Neither E2-induced activation nor the binding intensity of E2 to the Slack channel is blocked by tamoxifen, an ER antagonist/agonist. Thus, E2 activates a potassium channel, Slack, through a non-traditional membrane binding site, adding to known non-genomic mechanisms by which E2 exerts pharmacological and toxicological effects in the CNS.

Animals↗
PubMed2005

Subtoxic concentration of doxorubicin enhances TRAIL-induced apoptosis in human prostate cancer cell line LNCaP.

Most tumor cells are sensitive to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis but sparing to normal cells, thus providing therapeutic potential for clinical use. Some tumor cells are resistant to TRAIL-induced cell death while the sensitivity could be recruited with the existence of some chemical agents. In this study, human prostatic cancer cell line LNCaP was found to be resistant to TRAIL-induced apoptosis while it could be restored to TRAIL sensitivity with combination treatment of low concentration of doxorubicin. TRAIL receptor-1 (DR4) and TRAIL receptor-2 (DR5) were upregulated under the treatment of doxorubicin and verified to be responsible for TRAIL-mediated signal transduction. Furthermore, caspase-8 and caspase-3 were activated and drove their autocleavage into programmed cell death. Interestingly, apoptosis-inhibitory protein c-FLIP, but not Bcl-2 and XIAP was downregulated after doxorubicin treatment. Taken together, these findings suggested that the pathway of cell apoptosis induced by TRAIL was intact but under negative control. Subtoxic concentration of doxorubicin effectively boosted TRAIL sensitivity via depletion of antiapoptotic protein. These findings support the new strategies for killing tumors with TRAIL and chemical agents.

Antibiotics, Antineoplastic↗
PubMed2003

Ectopic synaptogenesis during retinal degeneration in the royal college of surgeons rat.

Rod photoreceptor-specific mutations cause ectopic synapses to form between cone photoreceptor terminals and rod bipolar cell dendrites in degenerating retinas of rhodopsin transgenic (P347L) pigs and retinal degeneration mice. Since the mutations occur in rod photoreceptor-specific genes in these two models, it is not known if ectopic synaptogenesis occurs specifically due to some rod photoreceptor cell-autonomous properties of a mutation or as a general consequence of photoreceptor degeneration. In the Royal College of Surgeons (RCS) rat, a mutation in the receptor tyrosine kinase gene, Mertk, causes failure of the retinal pigment epithelial (RPE) cells to phagocytose shed photoreceptor outer segments; subsequently, both rod and cone photoreceptors die. The non-phagocytic phenotype of the RCS rat is RPE cell-autonomous and the photoreceptors degenerate secondarily. Here we show that in 35-day-old RCS rats, where a majority of rod and cone photoreceptors remained, rod bipolar cell dendrites had abnormal (flat-contact type) synaptic contacts with rod and cone terminals. Demonstration of ectopic synapses in the RCS rat suggested that ectopic synaptogenesis could occur as a result of photoreceptor degeneration, even when the rods and cones were developmentally normal. This further supported the hypothesis that ectopic synaptogenesis may be a common step in the disease progression of different forms of retinal degeneration that include photoreceptor death as a feature, such as retinitis pigmentosa.

Animals↗
PubMed2002

Rectified heat transfer into translating and pulsating vapor bubbles.

It is well known that, when a stationary vapor bubble is subject to a sufficiently intense acoustic field, it will grow by rectified heat transfer even in a subcooled liquid. The object of this paper is to study how translation, and the ensuing convective effects, influence this process. It is shown that, depending on the initial temperature distribution and other factors, convection can cause a destabilization of the bubble or its faster growth. Significant effects occur in parameter ranges readily encountered in practice. The phenomena described can therefore be exploited for bubble management, e.g., by increasing the condensation rate or promoting faster bubble growth and coalescence. In a saturated or a superheated liquid, heat rectification and convection reinforce each other and the bubble growth is accelerated by a translatory motion.

Acoustics↗
PubMed2001

Establishment of in vitro cellular model predicting histocompatibility in allograft.

A novel in vitro cellular model producting recipient-donor histocompatibility in allograft was developed to select the donor validity. Fifteen couples of blood samples of donor and recipient in human BMT were examined using the model, and skin allograft in mice was performed to test the model. The results showed that the less the differences of histocompatibility evaluated by the model were, the later GVHR in human BMT occurred and the longer the survival time of skin allografts in mice. It was suggested that the model could be used to predict correctly histocompatibility between donor and recipient.

Animals↗
PubMed2001

The effect of fluid shear stress on ICAM-1 expression of rat brain microvascular endothelial cells.

Intercellular adhesion molecule-1 (ICAM-1) is an adherence molecule that is an important factor in many pathophysiological processes such as atherosclerosis, thrombosis and inflammation. It is secretion of endothelial cells by a variety of biochemical stimulations. But hemodynamic forces can also induce various functional changes in vascular endothelium. Some researches have proved that shear stress can modulate the expression of ICAM-1. But most of them examine the regulation of expression of ICAM-1 in human umbilical vein endothelial cells. There is no detail on the effect of shear stress (SS) on ICAM-1 expression of microvascular endothelial cells (RBMECs). In this experiment, we use cultured rat brain microvascular endothelial cells (RBMECs). By using the parallel plate flow chamber method, we give two magnitudes of lamminar shear stresses (0.2 dyn/cm2, 0.4 dyn/cm2) for different perieods of time on the slides of cells. Immunostaining method and image analysis shows a specific upregulation in ICAM-1 expression on RBMECs, which is different from endothelial cells of other species or vascular beds. Expression of ICAM-1 is increased 0.5h after the onset of SS, and reached its highest level 4h after onset of SS, then declines after that. The effect is time-dependent, not force magnitude-dependent. Endothelial cell surface expression of ICAM-1 in the supernatants of RBMECs exposed to SS was not modified excluding the possibility that RBMECs exposed to SS synthesize factors that upregulate ICAM-1. The experiment data are relevant to the current understanding of basic mechanisms that explain the signal transudation pathway occurring inside the endothelial cells under the effect of SS.

Animals↗
PubMed2001

Nitric oxide attenuates alpha(2)-adrenergic receptors by ADP-ribosylation of G(i)alpha in ciliary epithelium.

PURPOSE: To determine the mechanism by which nitric oxide (NO) regulates alpha(2)-adrenergic receptor coupling to adenylyl cyclase in bovine ciliary epithelium. METHODS: Ciliary epithelial explants were dissected, cultured, and labeled with [(3)H]adenine. [(3)H]Adenosine 3',5'-cyclic monophosphate (cAMP) was measured under basal conditions and after exposure to forskolin, isoproterenol, clonidine, yohimbine, pertussis toxin, and the NO donor spermine-NO. Endogenous and NO-stimulated ADP-ribosylation of ciliary epithelial membrane proteins was determined by [(32)P]nicotinamide adenosine diphosphate (NAD) labeling and autoradiography. The three isoforms of the G(i)alpha protein subunit were evaluated by Western blot analysis. RESULTS: Basal [(3)H]cAMP content was 13.4 +/- 1.3 picomoles/mg protein (SEM). Both isoproterenol and forskolin stimulated [(3)H]cAMP accumulation to 36.0 +/- 3.9 and 73.2 +/- 17.5 picomoles/mg protein, respectively. Clonidine did not affect basal [(3)H]cAMP levels, but attenuated both isoproterenol- and forskolin-mediated [(3)H]cAMP accumulation to 23.2 +/- 4.4 and 31.6 +/- 4.6 picomoles/mg protein, respectively. Yohimbine antagonized the clonidine-mediated adenylyl cyclase inhibition. Pertussis toxin blocked the effect of clonidine. In the presence of the NO donor spermine-NO, the clonidine-mediated inhibition of forskolin- and isoproterenol-stimulated cAMP accumulation was attenuated completely. NO significantly stimulated endogenous [(32)P]ADP-ribosylation of a 40-kDa membrane protein. Western blot analysis with specific antibodies revealed expression of all three G(i) subtypes--G(i1)alpha, G(i2)alpha, and G(i3)alpha--in bovine ciliary epithelium. CONCLUSIONS: NO attenuates alpha(2)-adrenergic receptor-mediated inhibition of adenylyl cyclase in ciliary epithelium through ADP-ribosylation of the G(i)alpha subunit. The findings demonstrate heterologous regulation between the NO and cAMP signaling pathways in ciliary epithelium.

Adenosine Diphosphate Ribose↗
PubMed2001

[The implications of the biological indices examination of bone marrow cells in myelodysplastic syndromes].

OBJECTIVE: To explore the biological characteristics of the hematopoietic cells in myelodysplastic syndromes(MDS) and the relationship between the biological indices and the disease progressing. METHODS: R banding technique for karyotype analysis, in vitro semi-solid culture for CFU-GM growth patterns, flow cytometry after monoclonal antibody labeling for proliferation cell nuclear antigen (PCNA) expression, flow cytometry after in vitro bromodeoxyuridine (BrdU) incorporation for cell cycle kinetics analysis, and X-linked HUMARA gene polymorphism assay for hematopoiesis clonality analysis were carried out in 37 MDS patients. RESULTS: 1. Cytogenetic abnormalities were detected in 31% of the MDS patients and AML transformation occurred in 2 of 9 with normal and 3 of 5 with abnormal chromosomal karyotypes. 2. The mean CFU-GM colony yield was decreased and cluster yield increased in the MDS patients. Disease progression in 6 of 9 with more CFU-GM cluster yields, while only 1 of 9 with either normal or no CFU-GM yields transformed into AML. 3. Percentages of PCNA-positive BMMNCs were significantly higher in MDS patients than in normal control (44.22% vs 26.82%, P < 0.01). RAEB/RAEB-t subtypes had significantly higher PCNA-positive cells (P < 0.01). 4. The mean BrdU labeling index of MDS marrow cells was lower (5.07%), the mean DNA synthesis time (Ts) and potential doubling time(Tpot) of MDS patients were longer than that of normal control (p < 0.01), and the increased Ts and T pot were related to the disease progression. 5. Monoclonal pattern of BMMNCs was detected in 5 of 7 heterozygous female RA patients and the other 2 were polyclonal hematopoiesis. All 3 RAEB and 1 MDS/AML were monoclonal hematopoiesis. CONCLUSION: With disease progressing and bone marrow blasts increasing, the biological nature of the hamatopoetic cells in MDS exhibited a tendency to transformation as follows: hematopoiesis converting into clonal, in vitro CFU-GM growth pattern approaching leukemic, PCNA expression increasing, and cell cycle prolonging.

Adolescent↗
PubMed2001

[Association between polymorphism of alpha 1-antichymotrypsin and apolipoprotein E gene and Parkinson's disease in Shanghai Hans].

OBJECTIVE: To explore the relationship between polymorphism of alpha 1-antichymotrypsin(AACT) and apolipoprotein E(ApoE) genes and the risk of Parkinson's disease(PD) in Shanghai Hans. METHODS: Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) were used to study the distribution of AACT and ApoE gene polymorphism in 64 PD cases and 101 healthy elderly persons as controls. Association analysis was performed using odds ratio (OR) and chi 2 test. RESULTS: No difference in distribution of AACT A/T allele polymorphism was found between PD cases and healthy controls(chi 2 = 0.83 P = 0.363 > 0.05), but AACT-AA genotype was associated with PD(OR = 2.68, chi 2 = 4.31 P = 0.038 < 0.05). The ApoE gene polymorphism was not associated with PD(allele: chi 2 = 2.85 P = 0.241 > 0.05; genotype: chi 2 = 9.25 P = 0.099 > 0.05). The AACT-AT genotype frequency in PD patients was significantly lower than that in the controls without ApoE epsilon 4 allele(OR = 0.47, chi 2 = 4.10 P = 0.043 < 0.05). In AACT-AT genotype the ApoE epsilon 4 allele was associated with PD(OR = 3.26, chi 2 = 5.53 P = 0.019 < 0.05). CONCLUSION: The AACT-AA genotype and AACT-AT genotype with ApoE epsilon 4 might be susceptible factors for PD in Shanghai Hans.

Adult↗
PubMed2001

Effects of recombinant human growth hormone (r-hGH) on experimental osteoporotic fracture healing.

OBJECTIVE: To observe the effect of recombinant human growth hormone (r-hGH) on osteoporotic fracture healing in rats, and to provide an effective therapy for osteoporotic fracture. METHODS: Thirty-six female 8-month-old SD rats were randomized into two groups: therapy group and control group. After the experimental model of osteoporotic fracture was established, the therapy group was treated with r-hGH of 2.7 mg/kg body weigh/day (1 mg=3 IU) for 10 days continuously by daily subcutaneous injection; whereas the control group was treated with equivalent saline. Plasma insulin-like growth factor I concentration was detected and bone mineral density (BMD) as well as biomechanical strength of callus were measured at 2, 4, 8 weeks. RESULTS: Plasma insulin-like growth factor I concentration in the therapy group was higher than that in the control group (P<0.005) at 2nd week and began to decline at 4th week. At 8th week, there was no significant difference between the two groups. At 4th week, callus area and BMD in therapy group were higher than those in the control group, but at 8th week, they were lower and BMD had a significant difference between the two groups (P<0.001). Biomechanical testing of callus showed that torsional strength of the therapy group was higher than that of the control group at 4th or 8th week, meanwhile maximum torsional angle had a significant difference between the two groups (P<0.005). CONCLUSIONS: The results show that exogenous r-hGH can stimulate osteoporotic fracture healing in rats.

Animals↗
PubMed2001

[Combined percutaneous ethanol injection through liver puncture and transcatheter hepatic arterial chemoembolization for hepatocellular carcinoma].

OBJECTIVE: To study the therapeutic effects of transcatheter arterial chemoembolization (TACE) combined with beta-ultrasound guided percutaneous ethanol injection (PEI) at multiple points for hepatocellular carcinoma. METHODS: Eighty-seven patients with hepatocellular carcinoma were divided into two groups: Group A, 45 patients were treated with TACE only, group B, 42 patients were treated with TACE plus PEI. RESULTS: In group A patients, the 1-, 2-, and 3-year survival rates were 66.7%, 41.4%, and 21.4%, respectively. Only 26.1% of cancer specimens showed complete necrosis by pathologic examination in group A. In group B, the 1-, 2-, and 3-year survival rates were 97.1%, 85.71% and 65.71%, respectively, with complete necrosis in 81.8%. CONCLUSION: The therapeutic effects of transcatheter arterial chemoembolization combined with percutaneous multiple point ethanol injection through liver puncture is much better than that of TACE alone.

Administration, Cutaneous↗
PubMed2001

[Study on the transformation from myelodysplastic syndromes into acute leukemias].

OBJECTIVE: To study the patterns of transformation from myelodysplastic syndromes (MDS) into acute leukemias (AL). METHODS: Leukemic transformation of MDS patients was dynamically followed up and the clinical manifestations, peripheral blood and bone marrow pictures, karyotypes, immunophenotypes, response to treatment and prognosis of post MDS acute leukemia (postMDS-AL) were observed. RESULTS: During the past eight year and seven months, 21 (13.91%) of 151 MDS patients progressed to overt leukemia with a median interval of 5 (1 - 21) months. There were no significant differences among the rates of leukemia from RA, RAEB and RAEB-t groups. The transformation was developed either gradually or rapidly. There were five parameters related to the leukemic transformation: under 40 years of age, pancytopenia, more than 0.15 blasts in bone marrow, at least two types of abnormal karyotype and combined chemotherapy. All of the 21 post MDS-AL were acute myeloid leukemia (AML); and most of them were M(2), M(4) and M(5). Two (9.52%) post MDS-AML developed extramedullary infiltration. Leukopenia was found in 47.62% of patients. Two third of the patients, whose bone marrows were generally hypercellular, showed neutropenias. After evolving into AML, 8 (47.06%) patients developed abnormal karyotypes. High expression of immature myeloid antigens, including CD(33) (49.83 +/- 24.50)%, CD(13) (36.38 +/- 33.84)%, monocytic antigen CD(14) (38.50 +/- 24.60)%, and stem cell marker CD(34) (34.67 +/- 30.59)% were found on bone marrow mononuclear cells of post MDS-AML cases. In some cases, lymphoid antigens, such as CD(5), CD(7), CD(9) and CD(19) were coexisted with myeloid antigens. A low complete remission rate (31.25%) and short survival duration with median survival of 6 (1 - 28) months were found in patients with post MDS-AML treated by induction therapy. CONCLUSION: MDS was at high risk of evolving into AML, either gradually or rapidly. Patients with post MDS-AML had specific biologic features and worse prognoses.

Acute Disease↗
PubMed2001

[The predomination of rotavirus G3 serotype among children with diarrhea in Lulong County in 1998].

OBJECTIVE: To investigate the epidemiology of rotavirus diarrhea among children in rural population. METHODS: 120 stool specimens collected from children with diarrhea during the winter of 1998 in Lulong County, Hebei Province were examined for rotavirus by PAGE and ELISA and for serotype by ELISA and PCR. RESULTS: Rotavirus was detected in children aged between 2-24 months. The positive rate of rotavirus was 39.2% and the ratio of male to female was 1-1.47. All rotavirus RNA profiles were long pattern. The distribution of rotavirus serotypes was type 3(61.7%), followed by type 1(36.2%), and type 4(6.4%). CONCLUSIONS: The epidemiology of rotavirus diarrhea during 1998 rotavirus season in Lulong County was similar to that of other regions in China, but rotavirus serotype G3 was a prevalent strain in Lulong County, which was uncommon and different from the predominant G1 in other places throughout China.

Child, Preschool↗
PubMed2001

The involvement of bradykinin in adrenaline-induced pulmonary edema in rats.

We investigated the effect of endogenous bradykinin on adrenaline-induced pulmonary edema (PE) by blocking bradykinin receptors. In preliminary experiments, a bolus injection of adrenaline (ADR; 10 microg/kg) solution (10 microg/ml) was determined to be an edematogenic dose for inducing PE. The lung body weight index (LBI) and incidence of PE (IPE) were determined. The IPE and LBI of the group pretreated with Des-Arg9-[Leu8]-Bradykinin (DA-BK, 50 microg/kg, 50 microg/ml) increased significantly compared with those of the control group (p<0.05). On the other hand, there were no remarkable changes in IPE and LBI in the groups pretreated with Hoe140 (D-Arginyl-[Hyp3, Thi5, D-Tic7, Oic8]-Bradykinin (100 microg/kg, 100 microg/ml), captopril (20 mg/kg, 20 mg/ml) or L-NAME (1 mg/kg, 1 mg/ml). Moreover, the IPE and LBI of the group co-treated with L-NAME and DA-BK decreased compared with the DA-BK group (p<0.05). Thus, bradykinin aggravates adrenaline-induced PE through activation of the B2 receptor by the kallikreins as a result of the ADR administration, although the precise mechanism is not known.

Adrenergic alpha-Antagonists↗
PubMed2001

[Effects of baicalin on hepatocyte apoptosis induced by TNF-alpha and act D in rats].

OBJECTIVE: To study the effects of baicalin on rat hepatocyte apoptosis induced by tumor necrosis factora (TNF-alpha) and actinomycin D (Act D) in vitro. METHODS: Hepatocytes were cultured with different concentrations of baicalin and the cell apoptosis was induced by TNF-alpha and Act D in vitro. After culturing for 24 h, the activity of hepatocysts was examined by MTT assay and the function of hepatocytes for secreting albumin was detected by bromocresolum Viride method. Agarose gelelectrophoresis and flow cytometric analysis were used to determine the apoptotic cells. RESULTS: The actively of the hepatocyte (A) and content of albumin (ALB) in the supernatant of cultured cells in the groups of 0.2 microgram.ml-1 and 2.0 micrograms.ml-1 of baicaline were significantly higher than those in apoptotic model group (A: P < 0.01; ALB: P < 0.01); respectively Even the ALB value in the group of 0.2 microgram.ml-1 baicalin was higher that of black control group (P < 0.01); The clear "ladder-like" streak-band of DNA fragments was found only in the apoptosis model group by the agarose gel electrophoresis. The flow cytometry showed that all the apoptosis rates in the three baicalin groups were lower than that of the apoptotic model group (P < 0.01). CONCLUSION: Baicaline can restrain rat hepatocyte apoptosis induced by TNF-alpha and ActD in vitro.

Animals↗
PubMed2000

Early loss of synaptic protein PSD-95 from rod terminals of rhodopsin P347L transgenic porcine retina.

Retinitis pigmentosa (RP), a type of retinal degeneration involving first rod and then slow cone photoreceptor degeneration, can be caused by any of a number of mutations in different genes. In the cases of mutations affecting rod-specific genes such as rhodopsin, it is unclear how the mutations may cause degeneration of cones. We have used the porcine retina, which is rod-dominated and has an abundance of cones, to study the mutation-induced changes in both rod and cone photoreceptors. Like patients with the same mutation, rhodopsin P347L transgenic swine manifest rod-cone degeneration. In addition, the rod bipolar cells fail to form synaptic connections with rods; instead, they form ectopic synapses with cones. The mechanisms that prevent the formation of the rod-rod bipolar cell synaptic connection are not known. We used specific antibodies and immunocytochemistry to show that the synaptic protein, PSD-95, is present in both normal and transgenic porcine retinas. During neonatal development, however, PSD-95 is lost from rod terminals in the transgenic swine. This loss is virtually complete (90%) by postnatal day 5, at a time when greater than 80% of rod cell bodies still remain. Furthermore, the remaining rods retain their outer segments and their gross morphology appears relatively normal. In contrast, PSD-95 expression continues in cone terminals, even in 10-month-old transgenic swine, where the rods have all disappeared and the cones show signs of severe degeneration. These results suggest that loss of PSD-95 may not be a general consequence of the deteriorating cell. Rather, the very early and selective loss of PSD-95 from the rod terminals may be causally related to the absence of rod-rod bipolar cell synapses in the rhodopsin P347L transgenic retina.

Animals↗