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Biomedical subjects

J H Zhou

Publications and source records attributed to J H Zhou.

At least 37 records · Page 2Linked to original sources
PubMed1999

Human blood dendritic cell-like B cells isolated by the 5G9 monoclonal antibody reactive with a novel 220-kDa antigen.

We developed a murine IgG1 mAb, 5G9, following immunization of a BALB/c mouse with Daudi cells. By immunoprecipitation, 5G9 reacted with a 220-kDa Ag on Daudi cells, which reduced to four subunits (55, 65, 80, and 85 kDa). mAb 5G9 bound to 40-60% of peripheral blood B cells, weakly reacted with monocytes and granulocytes, and did not bind to erythrocytes, platelets, T cells, or NK cells. mAb 5G9 brightly stained scattered cells in human tonsil sections, which appeared to be dendritic cells (DC) by morphology. mAb 5G9 also stained scattered cells in cytospin slides of monocyte-derived DC with long, thin, beaded membrane processes, morphologically distinct from other monocyte-derived DC. Positive selection of blood mononuclear cells with mAb 5G9 and sheep anti-mouse IgG Dynabeads demonstrated an enriched population of DC. By flow cytometry analysis, these cells were CD19, CD20, CD22, CD40, CD44, CD83, CD86, IgD, and HLA-Dr positive and either kappa- or lambda-L chain positive. They did not express CD3, CD4, CD5, CD10, CD11b, CD13, CD25, CD56, CD14, CD33, or CD64. Isolated 5G9+ cells were potent APCs in allogeneic MLR, compared with 5G9- PBMC, 5G9- B cells, monocytes, and monocytes cultured in IL-4 and GM-CSF for 24 h. mAb 5G9 defines a novel peripheral blood cell with B cell phenotype and DC morphology and function: DC-like B cells. The significance of this cell in immune responses requires further study.

Adult↗
PubMed1999

Expression of p16, Rb, and cyclin D1 gene products in oral and laryngeal squamous carcinoma: biological and clinical implications.

Cyclin D1, p16, and Rb genes play a critical role in the regulation of the G1-S transition of the cell cycle and are frequently altered in several neoplastic entities. Analysis of the protein products of these genes by molecular and immunohistochemical methods provides information on their functional status and allows for the phenotypic evaluation of tumor cells. We performed Western blotting and immunohistochemical analysis on tissues from 35 primary oral and laryngeal squamous carcinoma specimens with previous molecular analysis of the p16 gene and correlated the results with relevant clinicopathologic factors. Our study shows significant concordance between Western blotting and immunostaining results for cyclin D1 (P = .01), p16 proteins (P = .01), and Rb (P = .04). Heterogeneous staining of tumor cells and the positivity of non-neoplastic host elements for Rb by immunohistochemistry contributed to the discrepancy noted in some tumors by Western blotting. Significant reciprocal relationship between p16 and Rb proteins was observed (P < .001); in most tumors, absence of p16 (89%) and detectable Rb (94%) proteins were found. Two tumors had negative cyclin D1 expression, and one third overexpressed this protein. There was a lack of correlation between cyclin D1 overexpression and the clinicopathologic factors studied. Our results indicate that the absence of p16 in most of these tumors may constitute an early tumorigenic event and that the loss of the Rb function plays a minor role in HNSC.

Adult↗
PubMed1999

Production and characterization of monoclonal antibodies that recognize bovine Kit receptor.

Kit receptor is a transmembrane tyrosine kinase that is the receptor for stem cell factor (SCF). The extracellular domain of bovine Kit receptor (boKit) was produced by a baculovirus expression system. Six monoclonal antibody (MAb) clones designated as bK-1 to bK-6 were obtained upon immunization of mice with the recombinant protein. Immunoprecipitation and flow cytometric analysis indicated that all of the MAbs specifically bound to boKit expressed in COS-7 cells transfected with boKit cDNA. Four of the six MAbs neutralized the biological activity of recombinant bovine SCF, whereas the other two did not. The boKit-positive and boKit-negative cell fractions were sorted from cryopreserved bovine bone marrow cells by the use of MAb bK-1. Colony formation assays indicated that the cells which were able to grow in response to bovine SCF were enriched in the boKit-positive fraction. These MAbs would be valuable in studying possible boKit-positive cell species such as bovine hematopoietic cells, and in defining the biological role of Kit receptor in cattle.

Animals↗
PubMed1999

Elevated cyclin E levels, inactive retinoblastoma protein, and suppression of the p27(KIP1) inhibitor characterize early development of promyeloid cells into macrophages.

Cyclin-dependent kinase inhibitors such as p27(KIP1) have recently been shown to lead to cellular differentiation by causing cell cycle arrest, but it is unknown whether similar events occur in differentiating promyeloid cells. Hematopoietic progenitor cells undergo lineage-restricted differentiation, which is accompanied by expression of distinct maturation markers. Here we show that the classical growth factor insulin-like growth factor I (IGF-I) potently promotes vitamin D(3)-induced macrophage differentiation of promyeloid cells, as assessed by measurement of a coordinate increase in expression of the integrin alpha subunit CD11b, the CD14 lipopolysaccharide receptor, and the macrophage-specific esterase, alpha-naphthyl acetate esterase, as early as 24 h following initiation of terminal differentiation. Addition of IGF-I to cells undergoing vitamin D(3)-induced differentiation also leads to an early increase in expression of cyclin E, phosphorylation of the retinoblastoma tumor suppressor protein, and a doubling of the cell number. Early expression of CD11b (24 h) is simultaneously accompanied by inhibition in the expression of p27(KIP1). Cell cycle analysis with propidium iodide revealed that CD11b expression at 24 h following initiation of differentiation occurs at all phases of the cell cycle instead of only those cells arrested in G(0)/G(1). Similarly, development of a novel double-labeling intra- and extracellular flow-cytometric technique demonstrated that single cells expressing the mature leukocyte differentiation antigen CD11b can also incorporate the thymidine analog bromodeoxyuridine. Likewise, expression of the intracellular DNA polymerase delta cofactor/proliferating-cell nuclear antigen at 24 h is also simultaneously expressed with the surface marker CD11b, indicating that these cells continue to proliferate early in their differentiation program. Finally, at 24 h following induction of differentiation, IGF-I promoted a fourfold increase in the uptake of [(3)H]thymidine by purified populations of CD11b-expressing cells. Taken together, these data demonstrate that the initial steps associated with terminal macrophage differentiation occur concomitantly with progression through the cell cycle and that these very early differentiation events do not require the accumulation of p27(KIP1).

Cell Cycle↗
PubMed1997

Epstein-Barr virus BHRF1 prohibits the cells of nasopharyngeal carcinoma from apoptosis.

Epstein-Barr virus (EBV) is associated with nasopharyngeal carcinoma (NPC). The BHRF1 EBV protein is expressed at high levels in productively infected cells and certain latently infected cells. In order to investigate the effect of expression of BHRF1 on the biological behaviour of NPC cells, we constructed the BHRF1 high expression vector and transfected it into the NPC cell line, CNE2. Then, the alteration of proliferation and apoptotic rates in the cells were tested before and after camptothecin treatment. After treatment by camptothecin, BHRF1-CNE2 cells could constantly and slowly proliferate and its apoptotic rate was less than in control groups, and the number of cells in the G phase decreased and in the S phase increased. So, it suggests that BHRF1 expression can enhance the resistibility of CNE2 cells to DNA-damaging agents that cause apoptosis.

Antineoplastic Agents, Phytogenic↗
PubMed1997

[Determination of amoxicillin in human plasma by high performance liquid chromatography and its pharmacokinetics].

A rapid and sensitive assay for amoxicillin in human plasma has been developed using reversed phase high performance liquid chromatography. Plasma samples were prepared for analysis by addition of internal standard (tinidazole) followed by protein precipitation with HClO4. A YWG C18H37 column as stationary phase and a 0.033 mol.L-1 phosphate buffer (pH 7.2)--methanol mixture (85:15) as mobile phase were used with the UV detector set at 229 nm. The calibration curve was linear in the range from 0.2 microgram.ml-1 to 20.0 micrograms.ml-1 with gamma > 0.999. The analytical recovery of amoxicillin from plasma was > 86.7%. The relative standard deviations for within-day and between-day were < 5.48% and < 8.29%, respectively. Following oral administration of 500 mg in human volunteers, the peak levels of amoxicillin in plasma averaged 6.88 +/- 2.25 micrograms.ml-1 at 84.4 +/- 21.1 min. The mean half life time for amoxicillin was 62.8 +/- 14.6 min.

Adult↗
PubMed1996

Purification and activity of recombinant chicken stem cell factor produced by using a baculovirus vector.

Stem cell factor is a pleiotropic cytokine that plays an essential role in the development of hematopoietic cells, germ cells, and melanocytes. To obtain recombinant soluble chicken stem cell factor (chSCF), a baculovirus containing the cDNA encoding chSCF polypeptide from amino acids -25 to 170 was constructed. The chSCF produced in insect cells infected with the virus was purified by ion exchange column chromatography. The ability of the purified protein to induce the outgrowth of neurites from chicken dorsal root ganglia cultured in vitro was demonstrated.

Animals↗
PubMed1996

Conducting business in China.

Chinese culture is governed by an ancient set of values. Despite the gradual infiltration of Western culture, these historical practices remain highly visible in all interactions between Chinese people. For Western companies to set up and maintain viable businesses in China, it is essential that they have an understanding of Chinese heritage. This article identifies key elements of Chinese customs and business practices and explains their significance.

China↗
PubMed1996

[Effect of microinjection of angiotensin II into area postrema on renal sodium excretion].

It has been known that area postrema (AP) possesses angiotensin II (A II) receptors and senses directly the change of blood A II level. The effect of microinjection of A II into the AP on renal sodium excretion was studied in the present investigation. Our experimental results show that microinjection of A II (2, 20 ng) increases GFR, RPF and UNaV (P < 0.05). These changes can be abolished by A II antagonist, saralatin and renal denervation (P < 0.05). However microinjection of A II (20 ng) into NTS produces no such changes. These results strongly suggest that the A II induced changes of renal hemodynamics and urine sodium excretion are mediated through AP.

Angiotensin II↗
PubMed1995

Structure-activity relationships of cytotoxic cholesterol-modified DNA duplexes.

Short DNA duplexes with cholesterol linked at the 3'-terminus of each strand have unique, selective cytotoxic properties. The structural requirements for biological activity were explored through chemical synthesis of analogs and testing in cultured hepatoma cells. Effects of modifications to the sequence, backbone, 3'-sterol, 3'-linker, and 5'-terminus were evaluated. Self-complementary 3'-modified oligodeoxynucleotide (ODN) 10-mers were prepared from solid supports bearing the modification and linker of interest. Any changes to the normal phosphodiester backbone were poorly tolerated. The presence of cholesterol or a closely related sterol was an absolute requirement for activity. The length and position of attachment of the linker to cholesterol was important, with longer linkers showing reduced activity. Large, lipophilic groups at the 5'-terminus gave reduced cytotoxicity and poor solubility properties. The short length and unique structure of these ODNs allowed efficient automated synthesis on a 400 mumol scale and simplified purification.

Antineoplastic Agents↗
PubMed1995

Lysis of small cell carcinoma of the lung (SCCL) cells by cytokine-activated monocytes and natural killer cells in the presence of bispecific immunoconjugates containing a gastrin-releasing peptide (GRP) analog or a GRP antagonist.

Lung cancer remains the leading cause of cancer deaths in the United States. We have developed a new immunotherapeutic approach to the treatment of small cell carcinoma of the lung (SCCL) by targeting the gastrin-releasing peptide receptor (GRP-R) expressed on the surface of these cells. Bispecific immunoconjugates were constructed by chemical fusion of a GRP analog or a GRP antagonist with monoclonal antibodies directed to the cytotoxic trigger molecules Fc gamma RI and Fc gamma RIII on various immune effector cells. We demonstrated that these bispecific immunoconjugates bound to target SCCL cells in a dose-dependent manner. In the presence of these immunoconjugates, more than 80% of SCCL cells were lysed by cytokine-activated monocytes and natural killer (NK) cells measured by a 51Cr-release assay. These data indicate that bifunctional antibodies targeting GRP may have clinical use.

Antibodies, Bispecific↗
PubMed1995

[Pharmacokinetics of contragestazol (DL-111-IT), a new non-steroid antifertility agent in monkeys].

The pharmacokinetics of contragestazol, an early pregnancy temperating agent [3-(2-ethylphenyl)-5-(3-methoxyphenyl)-1H-1,2,4-triazole, DL-111-IT] was studied in Rhesus monkey. The blood concentration of DL-111-IT was determined by coupled column system HPLC method. Using an aqueous vehicle (20% cremophor EL in saline) DL-111-IT was injected intravenously to monkeys at doses of 25, 12.5 and 6.3 mg.kg-1. Blood drug concentration were measured. Using a programmable calculator the calculated pharmacokinetic parameters were as follows: alpha 1.83 h-1, 4.71 h-1 and 3.61 h-1, beta 0.15 h-1, 0.08 h-1 and 0.09 h-1; T1/2 beta 6.63 h, 10.2 h and 10.1 h; AUC 9.54 micrograms.h-1.ml-1, 3.94 micrograms.h-1.ml-1 and 3.75 micrograms.h-1.ml-1. An oil solution of DL-111-IT was injected intramuscularly in monkeys at doses of 50, 25 and 12.5 mg.kg-1. Its blood concentrations were determined at 0.08, 0.25, 0.5, 0.75, 1, 1.5, 2, 4, 8, 12 and 24 h after administration. From the time vs concentration curve, the pharmacokinetic parameters obtained were as follows: Ka 0.98 h-1, 1.03 h-1 and 1.45 h-1; Ke 0.42 h-1, 0.37 h-1 and 0.60 h-1; T1/2Ke 1.66 h, 1.90 h and 1.16 h; T (peak) 1.52 h, 1.57 h and 1.09 h; AUC 4.86 micrograms.h-1.ml-1, 5.61 micrograms.h-1.ml-1 and 1.74 micrograms.h-1.ml-1.

Abortifacient Agents, Nonsteroidal↗
PubMed1995

[Metallothionein and medicine].

Metallothioneins are attractive substances. One of the features of these proteins is the inducibility in response to heavy metals, to a great variety of metabolites and to stress factors. In mammalia, their synthesis may be induced by interleukin-6 in response to inflammation. Metallothionein could prevent renal toxicity of cDDP without compromising its anticancer activity. However, metallothionein is also implicated in the resistance to cDDP. There are now good evidences that metallothionein is involved in many diseases, such as inflammatory bowel disease, toxemia of pregnancy, liver disease, etc.

Animals↗
PubMed1995

Effects of Rehmannia glutinosa polysaccharide b on T-lymphocytes in mice bearing sarcoma 180.

AIM: To study immuno-antitumor action mechanism of RGP-b. RGP-b (Rehmannia glutinosa polysaccaride b) is a new component isolated from the herb, had an average molecular mass of 160 kDa and 5 kinds of monosaccharides as acid-splitting products. Its HPLC showed a main sharp peak at 162 kDa. METHODS: The kinetic effects of RGP-b on IL-2 secretion, cytotoxic T-lymphocyte (CTL) activities and L3T4+, lyt-2+ T-lymphocyte subset in mice bearing S180 were observed. RESULTS: RGP-b 10 or 20 mg kg-1 ip obviously attenuated the decrease of CTL cytotoxity caused by excessive tumor growth on d 9 after the administration, but only partly ameliorated the descent of IL-2. Its effect on lyt-2+ subset was quite parallel with that on CTL cytotoxity. RGP-b kept the ratio of L3T4+ to lyt-2+ subset lower than that of control. CONCLUSION: Improving the production of lyt-2+ CTL and its cytotoxity were an essential immuno-antitumor mechanisms of RGP-b.

Animals↗
PubMed1995

Monocyte-mediated lysis of acute myeloid leukemia cells in the presence of the bispecific antibody 251 x 22 (anti-CD33 x anti-CD64).

Immunotherapy using bispecific antibodies (BsAb) to direct immune effector cells toward target tumor cells has been shown to be effective in a number of studies. Several immune trigger molecules have been characterized. Among them, FcgammaRI appears to play an important role in antibody-dependent cellular cytotoxicity. It is expressed mainly on monocytes, macrophages, and neutrophils under certain clinical situations. The expression of FcgammaRI can be regulated by a variety of cytokines, primarily by IFN-gamma. Recent studies have shown that granulocyte-colony-stimulating factor (G-CSF) and granulocyte-macrophage-colony stimulating factor (GM-CSF) can increase the number of the FcgammaRI-positive monocytes, increase the expression of FcgammaRI on circulating neutrophils after in vivo infusion, and greatly enhance the cytotoxic activity of circulating neutrophils. CD33 is a glycoprotein expressed on the cell surface of mature monocytes, myeloid progenitor cells, and myeloid leukemic blasts, but not on the earliest hematopoietic progenitor cells and other normal tissues. Herein, we report the construction of a BsAb, 251 x 22, by conjugating an anti-CD33 mAb (mAb 251) to an anti-FcgammaRI mAb (mAb 22). The BsAb 251 x 22 is capable of enhancing the cytotoxicity of several leukemia cell lines by cytokine-activated monocytes. Our data also show that G-CSF- and GM-CSF-stimulated monocytes can mediate cytotoxicity of target leukemia cells comparable to that of IFN-gamma-stimulated monocytes. The expression of FcgammaRI on monocytes after 24-h in vitro incubation with G-CSF and GM-CSF was increased, although not significantly. Prolonged incubation of monocytes with G-CSF for 48 h significantly increased the FcgammaRI expression. Because humanized anti-CD33 and anti-FcgammaRI mAb are available, and because GM-CSF and G-CSF have been used widely for patients after chemotherapy to stimulate the recovery of myeloid hematopoiesis, additional clinical development of this project is feasible. A BsAb comprised of humanized anti-CD33 and anti-FcgammaRI could have clinical application in the treatment of myeloid leukemia, especially in the management of minimal residual disease.

Acute Disease↗
PubMed1994

Discovery of short, 3'-cholesterol-modified DNA duplexes with unique antitumor cell activity.

A new class of modified oligodeoxynucleotides with unique, selective cytotoxic properties has been discovered. Self-complementary, 3'-cholesterol-modified oligodeoxynucleotides caused morphology changes and death in certain cancer cell lines, whereas other cell lines were unaffected. Susceptible cells were killed in a dose-dependent manner at submicromolar concentrations. Optimum potency was exhibited by phosphodiester duplexes approximately 10 base pairs in length, and base composition was important only in the context of duplex stability. Phosphorothioate analogues were less potent. Although the molecular mechanism of action of these unique compounds is not yet known, they offer potential applications in cancer therapy and in studies of cell death. In addition, the path toward elucidation of the structure-based biological activity of these oligonucleotides should be especially instructive for researchers studying sequence-specific effects.

Animals↗