Search PubMed⌕ Search

Biomedical subjects

Y Zhou

Publications and source records attributed to Y Zhou.

983 records · Page 55Linked to original sources
PubMedDate not supplied

Distribution of biglycan and its propeptide form in rat and bovine aortic tissue.

The matrix proteoglycan biglycan was identified in bovine and rat aortic tissue by Western blot analysis and by immunohistochemistry, using polyclonal antibodies raised against peptides of the propeptide and the hypervariable region of the rat biglycan core protein. Western blot analysis of proteoglycans isolated from bovine and rat aortas by ion exchange chromatography and treated with chondroitin ABC lyase, with antibody against propeptide, demonstrated core proteins with molecular weights ranging from 43,000 to 45,000 daltons. Similar results were obtained with Western blot studies using the peptide antibody to the hypervariable region of biglycan, except the antibody did not recognize the core protein of bovine biglycan. Location of biglycan within bovine and rat aortic tissue sections by immunoperoxidase histochemistry using the antibody raised against the propeptide revealed intense intracellular staining of medial myocytes and endothelial cells but no extracellular staining. In contrast, immunohistochemistry performed with the purified antibody to the hypervariable region revealed significant extracellular staining of the adventitia proximate to the media and of the endothelial lining but no intracellular staining of rat aortic tissue, with no observable staining of bovine aortic tissue. These data demonstrate that, in contrast to cultured smooth muscle cells, biglycan containing the propeptide is not secreted and deposited within the extracellular matrix by smooth muscle cells and endothelial cells from aortic tissue.

Amino Acid Sequence↗
PubMedDate not supplied

Electroacupuncture accelerated the expression of c-fos protooncogene in serotonergic neurons of nucleus raphe dorsalis.

It has been proposed that the FOS protein encoded by c-fos protooncogene functions as a nuclear "third messenger" molecule that couples short-term extracellular signals to long-term alterations in cell function, by regulating the expression of specific target genes. In the present study, immunocytochemical double staining technique was used to investigate the effects of electroacupuncture on the expression of c-fos oncogene in the serotonergic neurons in the nucleus raphe dorsalis (NRD) that has been known to play an important role in the endogenous analgesic system of the brain. The number of FOS positive serotonergic cells in the NRD increased significantly after the electroacupuncture stimulation. These results indicate that electroacupuncture can activate central serotonergic neurons at gene expression level.

Animals↗
PubMedDate not supplied

Inhibition of CDK2, CDK4 and cyclin E and increased expression of p27Kip1 during treatment with interferon-alpha in carcinoid tumor cells.

IFN-alpha has presented antitumor effect in about 50% of carcinoid tumor patients, though the antitumor mechanism of IFN-alpha is still to be elucidated. In this study we demonstrated that IFN-alpha could result in accumulation of S-phase population and upregulation of cyclin-dependent kinase inhibitor (CKI), p27. Moreover, IFN-alpha inhibits DNA synthesis assessed by [3H] thymidine incorporation and colony formation on soft agar. Immunodepletion of p27 increased CDK2- and cyclin E-associated kinase activities. These data suggest that IFN-alpha exerts its antiproliferative effects in the neuroendocrine differentiated cell lines by: 1) inhibition of DNA synthesis and colony formation, 2) upregulation on the mRNA and protein expressions of the CKI, p27.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

Overexpression of human reticulon 3 (hRTN3) in astrocytoma.

Neuroendocrine-specific protein (NSP) reticulons (RTN) are endoplasmic reticulum-associated protein complexes, which are localized in the endoplasmic reticulum (ER) and identified as markers for neuroendocrine differentiation. At least 4 different RTN genes have been identified in mammals, but in most cases, the functions of the encoded proteins except mammalian RTN4-A and RTN4-B are still elusive. In the present study, the expression of human reticulon 3 (hRTN3) in a variety of tissues was investigated. Northern blotting hybridization revealed higher expression of hRTN3 in normal brain and some endocrine-related organs such as thyroid relative to other non-endocrine organs. Twelve surgical specimens meeting the histological criteria for astrocytoma grade II, III and IV were investigated by in situ hybridization and immunohistochemical analysis, which demonstrated the overexpression of hRTN3 in astrocytoma tumor cells, while in non-cancerous brain tissues hRTN3 was mainly expressed in neurons and almost no signals in glia cells could be detected. The differential expression of hRTN3 between astrocytoma and non-cancerous tissue may provide insight into the progress of astrocytoma.

Aged↗
PubMedDate not supplied

Vitrification of encapsulated hepatocytes with reduced cooling and warming rates.

We have used microencapsulated hepatocytes as model to develop a method of vitreous cryopreservation of large quantities of cell-containing constructs. The method included a pre-equilibration procedure in which the amount of penetrating cryoprotectant was gradually increased by 15% in each step. The optimal vitrification solution consists of 40% ethylene glycol and 0.6M sucrose. The concentration of 1M sucrose used for the first dilution solution with subsequent decrease of sucrose concentration to 0.7 M sucrose and by 0.2-0.15M for each subsequent step. This sucrose dilution procedure had no adverse effect on cell functions. Three cooling rates (400 degrees C/min and above) and three warming rates (650 degrees C/min and above), in combination with the proposed vitrification solution, were equally effective. The optimization of the procedure and solutions allow microencapsulated hepatocytes to be preserved with almost 100% retention of cell functions and no detectable damage to the fragile microcapsules. The de-linking of the cooling/warming rates with the effectiveness of vitrification potentially paves the way for large scale cryopreservation of complex tissue engineered constructs.

Animals↗
PubMedDate not supplied

Effect of pulsatile reperfusion on myocardial high energy phosphates following global ischemia.

To evaluate the effects of pulsatile reperfusion (PR) on the postischemic myocardial phosphometabolites, 17 sheep were put on cardiopulmonary bypass (CPB) and randomly divided into a pulsatile group (P group) and nonpulsatile group (NP group). The heart was arrested by global ischemia for 45 minutes, then defibrillated and reperfused for 2 hours while the circulation was supported by CPB. Myocardial needle biopsies were obtained, and ATP, ADP, and AMP were measured with high performance liquid chromatography. There were no significant differences between the two groups in myocardial ADP and AMP. However, after 120 minutes of reperfusion, the myocardial ATP was restored in the P group, but continued to decrease further in the NP group. Experimental results imply that PR might reduce reperfusion injury and promote recovery of the ischemic myocardium.

Adenosine Triphosphate↗
PubMedDate not supplied

Effects of pulsatile reperfusion on globally ischemic myocardium.

To evaluate the effects of pulsatile reperfusion on the post ischemic myocardium, two categories of sheep were put on cardiopulmonary bypass (CPB). In Category I, the hearts of 23 sheep were arrested by global ischemia for 30 min, reperfused with pulsatile flow in 10 animals (P group), and non pulsatile flow in 13 animals (NP group), and then defibrillated. The incidence of ventricular fibrillation was much higher in the NP group than the P group, 77% versus 40% (p < 0.05). The lipoperoxide products and creatinine kinase from coronary sinus blood were elevated, but there were no significant differences between the two groups during 2 hour reperfusion. In the P group, less ultrastructural damage was observed, and Na+ and H2O accumulations in the subendomyocardium were significantly less than in the NP group, at 7.11 +/- 0.60 versus 9.98 +/- 1.10 mg/g dry weight (p < 0.05) and 82.58 +/- 0.47% versus 84.3 +/- 0.38% (p < 0.05), respectively. In Category II, the ischemic time of 17 sheep (eight in the P group, nine in the NP group) was prolonged to 45 min, and animals were supported by CPB after defibrillation. Myocardial energy phosphates were measured with high-performance liquid chromatography, and triphenyltetrazolium chloride was used to delineate the infarct size. After 2 hour of reperfusion, there were no significant differences in myocardial AMP and ADP between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMedDate not supplied

Synthesis of an O-palmitoylated 44-residue peptide amide (PLTX II) blocking presynaptic calcium channels in Drosophila.

PLTX II, a presynaptic calcium channel blocker in Drosophila isolated from the plectreurys spider venom, is a 44-residue peptide containing ten Cys residues and an O-palmitoylated threonine amide at the carboxy-terminus. In this study, the palmitoylated peptide was synthesized in solution by applying our maximum protection strategy using the HF method at the final deprotecting step. Before designing the synthesis, we examined the stability of the palmitoyl moiety under the conditions for the synthesis of the peptide using several model peptides. The O-palmitoyl group was confirmed to be stable during elongation of the peptide bonds, but was partially removable during the deprotection reaction in HF. The depalmitoylation reaction in HF was temperature- and time-dependent. Therefore, the decision was made to protect the Asp residues with benzyl ester, since it is more susceptible to HF than cyclohexyl ester, which is now commonly used in the Boc-based, solid-phase synthesis. Thus, the HF reaction was carried out at -10 degrees or -15 degrees C for 1 h in order to reduce the extent of the depalmitoylation reaction. The resulting palmitoylated and depalmitoylated products were separated, the remaining Acm groups were removed using Hg(OAc)2, and then the completely deprotected peptides were folded to their native forms. The final palmitoylated peptide was proven to be identical with the natural one using various HPLC systems and by bioassay.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMedDate not supplied

A mechanical auxiliary ventricle. Histologic responses to long-term, intermittent pumping in calves.

The mechanical auxiliary ventricle (MAV) is an avalvular, inseries left ventricular assist device (LVAD) comprised of a 60 cc Biomer blood pump implanted in the descending thoracic aorta, a percutaneous access device (PAD), and an external pneumatic drive. In four calves the MAV was implanted and activated intermittently for 192, 249, 423, and 785 days, respectively; no anticoagulants were administered. When the animals were killed, the implants were retrieved, and autopsies, including gross, light microscopic, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) examinations, were performed. The MAV was securely attached to the aorta in every animal. A thin, even smooth, pseudoneointimal layer (PNI) contiguous with the aorta at the level of the suture line covered the MAV's blood-contacting surface. Areas of calcification beneath the PNI, expected in growing animals with implanted pumping devices, were noted. At autopsy there was no evidence of thrombosis or infection in the regions of the blood pump or the PAD. These findings confirm the calves' benign histologic response to the MAV, and together with the results of hematologic and biochemiccal studies, and bench tests of system components being reported elsewhere, indicate the system's readiness for limited clinical investigation in selected patients with chronic congestive failure.

Animals↗
PubMedDate not supplied

Anti-neoplastic properties of human corticotropin releasing factor: involvement of the nitric oxide pathway.

We report a series of the in vivo and in vitro studies that evaluate the anti-neoplastic potential of hCRF in W256 rat mammary carcinoma. Using magnetic resonance imaging (MRI) and direct measurements of tumor and peritumoral brain water content we found that hCRF treatment (100 micrograms/kg subcutaneously twice a day for 3 days) caused significant inhibition of growth and vascular permeability of the i.c. W256 tumors. hCRF also exhibited antiproliferative and differentiation-inducing effects in W256 cells in vitro. The calculated IC50 values were 70 nM and 100 nM of hCRF, as measured by digital videomicroscopic quantitation of tumor cell population growth rate and by [3H]-thymidine incorporation assay, respectively. The observed effects in W256 cells were CRF receptor mediated. This was shown in two ways: by the presence of relatively high levels of CRF1 receptor mRNA in W256 cells, and by the fact that the tumor growth inhibitory and differentiation inducing effects of hCRF in vitro were abolished by the CRF receptor antagonist a-helical CRF (9-41). Antiproliferative and differentiation inducing effects of hCRF in W256 cells involve activation of nitric oxide synthase (NOS) and L-arginine-NO pathway. This was shown by using the inhibitor of NOS, the L-nitro-arginine methyl esther (L-NAME), which prevented the antiproliferative and differentiation inducing effects of hCRF in vitro. The cytotoxicity of NO in W256 cells was assessed by the addition of sodium nitroprusside (SNP) to the media. SPN exhibited dose-dependent cytotoxicity in W256 cells with IC50 of 100 muM SNP as measured by [3H]-thymidine incorporation assay. We conclude, that hCRF has substantial anti-neoplastic effects which include inhibition of proliferation and induction of differentiation of the tumor cells in vitro, and a decrease in tumor vascular permeability (and possibly neo-angiogenesis) in vivo.

Animals↗