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Biomedical subjects

Bo Zhang

Publications and source records attributed to Bo Zhang.

At least 253 records · Page 14Linked to original sources
PubMed2002

Development of a monoclonal antibody for neutralization of human telomerase activity.

To develop monoclonal antibodies (MAbs) to neutralize human telomerase, an epitope (hTERT(7)) in reverse transcriptase domain of hTERT was synthesized and was used to immunize BALB/c mice. Hybridomas were generated and screened by enzyme-linked immunoadsorbent assay (ELISA) for specific MAbs. One hybridoma M2 clone, isotyped IgG(1), was established. The competitive assay confirmed that the M2 antibody was hTERT(7) specific, and the affinity constant was about 1 x 10(6) M(-1). M2 could recognize cell extracts from HeLa cancer cells but not those of normal 2BS cells in ELISA assay. For in situ staining immunohistochemically, the positive staining presented in the nuclear compartment of HeLa, while 2BS was nonreactive. In TRAP-PCR ELISA, M2 markedly decreased the activities of human telomerase in HeLa cells. The sequencing of M2 heavy chain variable region proved its mouse origin. The results demonstrated that the developed mouse MAb should be hTERT specific and could not only recognize native cellular hTERT in ELISA and immunohistochemistry, but also neutralize telomerase activities. Thus, it could be hoped that the antibody could be used in clinical diagnosis and treatment of cancers.

Amino Acid Sequence↗
PubMed2002

Induction effects of sulfur dioxide inhalation on chromosomal aberrations in mouse bone marrow cells.

To investigate the induction of chromosome aberrations (CA) in mouse bone marrow cells by sulfur dioxide (SO(2)) inhalation, mice were treated by SO(2) exposure for 4 h/day for 7 days at various concentrations of SO(2), then mitotic indices and CA in mouse bone marrow cells were analyzed. The present results show that SO(2) might increase the frequencies of CA and aberrant cells in mouse bone marrow in a dose-dependent manner. The frequencies (%) of aberrant cells in mouse bone marrow induced by SO(2) at concentrations of 0, 7, 14, 28 and 56 mg/m(3) were 1.81, 3.00, 3.58, 4.26, 4.86, respectively. At low concentrations SO(2) induced only chromatid-type CA, while at high concentrations SO(2) induced both chromatid-type and chromosome-type CA. SO(2) inhalation decreased the mitotic indices of bone marrow cells. The results imply that SO(2) inhalation may inhibit mitoses and increase CA frequencies of bone marrow cells and that it is a clastogenetic and genotoxic agent. Long exposure to SO(2) pollution at low concentrations in the environment may be a potential risk for induction of cytogenetic damage in vivo in humans.

Administration, Inhalation↗
PubMed2002

Bovine membrane-type 1 matrix metalloproteinase: molecular cloning and expression in the corpus luteum.

Matrix metalloproteinase-2 (MMP-2) is produced as a zymogen, which is subsequently activated by membrane-type 1 metalloproteinase (MT1-MMP). The objectives of the present study were to clone bovine MT1-MMP and to investigate its expression in the corpus luteum. Corpora lutea were harvested from nonlactating dairy cows on Days 4, 10, and 16 of the estrous cycle (Day 0 = estrus; n = 3 for each age). The bovine MT1-MMP cDNA contained an open reading frame of 1749 base pairs, which encoded a predicted protein of 582 amino acids. Northern blotting revealed no differences (P > 0.05) in MT1-MMP mRNA levels between any ages of corpora lutea. Western blotting demonstrated that two species of MT1-MMP, the latent form ( approximately 63 kDa) and the active form ( approximately 60 kDa), were present in corpora lutea throughout the estrous cycle. Active MT1-MMP was lower (P < 0.05) in early stages of the corpus luteum than the mid and late stages, where MMP-2 activity, as revealed by gelatin zymography, was also elevated. Furthermore, immunohistochemistry revealed that MT1-MMP was localized in endothelial, large luteal, and fibroblast cells of the corpus luteum at different stages. Taken together, the differential expression and localization of MT1-MMP in the corpus luteum suggest that it may have multiple functions throughout the course of the estrous cycle, including activation of pro-MMP-2.

Animals↗
PubMed2002

Pravastatin promotes coronary collateral circulation in patients with coronary artery disease.

BACKGROUND: Previous studies suggested that hydroxymethylglutaryl coenzyme A reductase inhibitor (statin) promotes collateral circulation in ischemic limbs of rabbits. The present study was designed to determine the association between treatment with pravastatin and the development of coronary collateral circulation as assessed by the Rentrop Score in patients with coronary artery disease (CAD) in a case-control study. DESIGN: The study included patients who had one (1-V), two (2-V) or three (3-V) significantly stenosed vessels. Patients who did and did not receive pravastatin were defined as case participants (n = 42) and control participants (n = 100), respectively. RESULTS: The case participants included a higher percentage of 3-V patients with a Rentrop Score 1 compared to the control participants but there was no difference among 1-V and 2-V patients, suggesting that pravastatin was associated with coronary collateral circulation independent of the number of stenosed vessels. Patients with 3-V disease who were treated with pravastatin were most likely [odds ratio (confidence interval), 17.4 (4.4-115)] to develop collateral circulation, as assessed by multiple logistic regression analysis. CONCLUSIONS: Treatment with pravastatin was associated with the development of collateral circulation in patients with CAD, suggesting that such action constitutes part of the pleiotropic effects of statin.

Aged↗
PubMed2002

Intravenous chemotherapy for resected gastric cancer: meta-analysis of randomized controlled trials.

AIM: To assess the safety and efficacy of different intravenous chemotherapeutic regimens in patients with gastric carcinomas who had undergone gastrectomy. METHODS: A meta-analysis of all the relevant randomized controlled trials (RCTs) was performed. Language was restricted to Chinese and English. RCTs were identified from Medline and Embase (1980-2001/4), and Chinese Bio-medicine Database (1990-2001/1). Literature references were checked at the same time. We included randomized and quasi-randomized trials comparing the efficacy of intravenous chemotherapy after gastrectomy with that of surgery alone in patients with confirmed gastric carcinomas who had undergone gastrectomy. Selection criteria were: randomized or quasi-randomized trials with following-up results; Trials could be double-blind, single-blind or not blind; Chemotherapy groups were given intravenous chemotherapy after gastrectomy without neo-adjuvant chemotherapy, intraperitoneal hyperthermic perfusion, radiotherapy or chemoimmunotherapy; Controlled group included those receiving gastrectomy alone. The following data were extracted: the number of survival and death by the end of the follow-up; the different agents and doses of the intravenous chemotherapy; the baseline of the chemotherapy group and the controlled arm; the serious adverse events; the statistical consideration; cost-effectiveness analysis. The statistical analysis was performed by RevMan4.1 software which was provided by the Cochrane Collaboration. A P value of <0.05 was considered statistically significant. Meta-analysis was done with random effects model. Heterogeneity was checked by chi-square test. Sensitivity analysis was performed by excluding the trials in which Jadad-scale was only 1 score. The result was expressed with odds ratio (OR) for the categorical variable. RESULTS: Fourteen trials involving 4543 patients were included. Meta-analysis was done with random effects model. Heterogeneity and sensitivity analysis were performed also. The effect of intravenous chemotherapy after gastrectomy was better than surgery alone (odds ratio 0.56, 95 %CI 0.40-0.79). There was a significant difference between the two groups by u-test (P=0.0008). Sensitivity analysis revealed the same difference (odds ratio 0.81, 95 % CI 0.70-0.94). Of fourteen trials, only three studies were of high quality according to the Jadad-scale (with three score). There was one meta-analysis trial and the others, about ten trials, were of low quality. There was no trial which mentioned sample-size calculation, allocation concealment, intention-to-treat analysis. Most of the trials didn't describe the blind-procedure. There were five trials which detailed the side-effects according to the toxicity grade by WHO standard. The side-effects halting treatment were haematologic and biochemical toxicity, debilitating nausea and vomiting. There were two patients died of chemotherapy toxicity. CONCLUSION: Based on the review, intravenous chemotherapy after gastrectomy may have positive treatment effect on gastric cancer. However, the evidence is not strong because of the general low methodologic quality of the RCTs. Therefore, we can't make the conclusion that intravenous chemotherapy after gastrectomy may have better treatment effect on gastric cancer than that of surgery alone. Rigorously designed, randomised, double-blind, placebo-controlled trials are required.

Antineoplastic Agents↗
PubMed2002

An approach to the fluctuation mechanism of ecotone.

In this paper, the relationship among land productivity, population pressure and the fluctuation mechanism of ecotone is analyzed, taking counties and banners of southeast Inner Mongolia plateau as an example, which is the most fragile part in the farming and husbandry interleaving belt of north China due to its severe desertification degree and low level of economic development. The Cv for the total output value of agriculture decreases from southeast to northwest, with the same rule as which the overloading population cumulated distributes, and both indicators have close relation with the high linear coefficient of 0.83. These reveal the fluctuation mechanism for ecotone: fluctuation of the level of economic development is a scientific and practical measure both to weakness degree and to instability of ecotone, because it is a synthesized response to the variation of climate as well as irrational land uses, which reinforce and magnify the fluctuation. In detail, the heavier the population overloading, the severer the grassland reclamation, the stronger the dependence of regional productivity on rainfall, the lower the level of economic development, the rougher the fluctuation of ecotone, but the weaker the PRED system.

Agriculture↗
PubMed2002

[Monoclonal antibodies against human telomerase reverse transcriptase: preparation, characterization, and application].

OBJECTIVE: To develop monoclonal antibodies against the catalytic subunit of human telomerase hTERT for its expression detection of human tumors. METHODS: A dominant epitope in hTERT (peptide hTERT(9))was automatically synthesized based on Fmoc method, and was used to immunize BALB/c mice. Hybridomas were generated and screened by ELISA for specific monoclonal antibodies, and the characterization of which were performed by Western blotting and immunohistochemical staining. RESULTS: Antigenic peptide hTERT(9) was synthesized and confirmed by MALDI-TOF-MS and HPLC analysis. Three hybridoma cell lines secreting anti-hTERT(9) antibodies designated as H4, G8 and A11 were established after primary screening and consequent three rounds of limited dilution. Both of H4 and G8 were IgM, while A11 was IgG1 in isotyping. The competitive assay showed that the antibodies were hTERT(9) specific, and the affinity of G8 was stronger than that of H4 and A11 assayed by affinity ranking. However, in Western blotting, both of H4 and G8 stained an about 123 000 protein band with HeLa and 293 cell extracts but not with normal 2BS cells. Besides, positive staining presented in the nucleus of HeLa, while 2BS was non-reactive immunohistochemically. The sections from paraffin-embedded blocks of 127 cases of human cancer, 40 of precancerous and 19 of benign tumors were in situ stained by G8 antibody, the results showed that the human cancer tissues were 80.31% (102/127) positive in specific nuclear reaction, on the contrary, only a minority of precancerous lesions present weak positive (17.5%, 7/40), and negative in benign tumors (0/19). CONCLUSIONS: The monoclonal antibodies developed against synthetic peptide were hTERT-specific and could recognize both the native and the denatured form. Thus their use in immunoblotting or immunohistochemistry for detecting the telomerase hTERT expression of cancer cell and tissues was promising.

Animals↗
PubMed2002

[Micronuclei induced by chronic inhalation of SO2 in mouse bone marrow cells].

In the chronic inhalation experiment of sulfur dioxide(SO2), micronuclei(MN) frequencies in the polychromatophilic erythroblasts(PCE) of mouse bone marrow and the frequencies of cells with MN were significantly increased in dose-dependent manner. There was a significant difference between the male and the female animals. The results also showed that SO2 inhibited urethone-induced MN formation. These results furtherly confirm that SO2 inhalation was a clastogenic and genotoxic agent to mammalian cells, and the combined effects of SO2 and other mutagens are complex.

Administration, Inhalation↗
PubMed2002

[Cryopreserved viable pedicled aortic homografts for complex congenital heart diseases: report of 2 cases].

OBJECTIVE: To report the authors' experience in treating complex congenital heart diseases with cryopreserved viable pedicled aortic homografts (CVAHs). METHODS: CVAHs were obtained within 3 h after death of donors younger than 35 years old due to non-cardiovascular and non-infectious diseases. After routine treatment, the homografts were cryopreserved in liquid nitrogen and thawed in 0.9% sodium chloride solution at 37 to 42 degrees celsius before use. A CVAH was used as a valved conduit to connect the pulmonary artery and right ventricle in one case of double-outlet right ventricle, pulmonary stenosis and coronary artery deformation. In another case of severe tetralogy of Fallot, a CVAH was used as a valved patch to enlarge the right ventricle outlet. RESULTS: The homografts were preserved satisfactorily. The surgical results of the 2 cases with congenital heart diseases were satisfactory in perioperative and follow-up periods. CONCLUSION: CVAH is a good substitute to rebuild right ventricle-pulmonary artery connection in treatment of complex congenital heart diseases.

Aorta↗
PubMed2002

[Induction effects of sulfur dioxide inhalation on chromosomal aberrations in mouse bone marrow cells].

OBJECTIVE: To investigate the induction effects of sulfur dioxide (SO(2)) inhalation on chromosomal aberrations (CA) in mouse bone marrow cells. METHODS: The mice were treated with SO(2) for 4 h/day x 7 days at various concentrations of SO(2), then mitotic indices and CA in the bone marrow cells were analyzed. RESULTS: SO(2) increase the frequencies of CA and aberrant cells in mouse bone marrow cells in dose-dependent manner. The frequencies (%) of the aberrant cells in mouse bone marrow cells induced by SO(2) at concentrations of 0, 14, 28, 56 and 84 mg/m(3) were 1.81, 3.00, 3.58, 4.26 and 4.86, respectively. SO(2) at low concentrations induced only chromatid-type CA, but at high concentrations it induced both chromatid-type and chromosome-type CA. SO(2) inhalation decreased the mitotic indices of the bone marrow cells. CONCLUSIONS: SO(2) inhalation may inhibit mitoses and increase CA frequencies of the bone marrow cells; therefore, it is a clastogenetic and genotoxic agent. It implies that long time exposure of SO(2) pollutant at low concentration in air may be a potential risk to induce damage of cytogenetic material in humans.

Administration, Inhalation↗
PubMed2002

Single domain antibody to human telomerase catalytic subunit: preparation and characterization.

OBJECTIVE: To develop a recombinant single domain antibody against hTERT, human telomerase catalytic subunit. METHODS: A previously prepared His-tagged hTERT fusion protein was used as the antigen, and the variable regions in heavy chain (VH) of immunized mice were RT-PCR amplified and cloned into the pCANTAB 5E, a phagemid vector. By transfection, the display library of mouse VH was developed. The candidate clones were selected by affinity panning, and soluble VH were obtained after expression in E. coli, HB2151. The resultant single VH antibodies were characterized on their binding potentials by western blotting. RESULTS: An about 350 bp VH fragment was amplified from spleen cells of mice immunized by His-tagged hTERT and expressed by phage displayed as VH library. The size of the library was 8 x 10(4). After three rounds of affinity panning, 4 independent clones were chosen and consequently expressed as soluble single domain antibodies (Mr = 16 000). In Western blot analysis, the single domain antibody from 2 of 4 clones proved to react with the His-tagged hTERT fusion protein (Mr = 167 000) without dependence of His-tags and also detect the native hTERT (Mr = 127 000) extracted from the human HeLa cancer cell line. DNA sequencing showed both of the single domain antibodies were encoded by the heavy chain variable region of the mouse. CONCLUSIONS: The single domain antibodies developed were hTERT recognizable and hTERT specific, thus providing a basis for application of recombinant single domain antibody in inhibition of telomerase activity and anticancer therapy.

Amino Acid Sequence↗
PubMed2002

[Study on the mechanism of hepatocytic insulin signal transduction defects in severely scalded rats].

OBJECTIVE: To investigate the mechanism of hepatocytic insulin signal transduction defects in severely scalded rats, so as to clarify the molecular basis of postburn insulin resistance. METHODS: Wistar rats inflicted by 30% III degree scalding on the back were employed as the model. The rat hepatocytic insulin receptor was partially purified by wheat-germ agglutinin (WGA)-sepharose 4B affinity chromatography. The change of receptor tyrosine protein kinase (TPK) activity, the receptor beta-subunit autophosphorylation and the hepatocytic insulin receptor binding behavior of scalded rats during early stage of scalding were observed by means of insulin receptor binding test, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) autoradiography of phosphorylation of insulin receptor and phosphorylation of exogenous substrate. RESULTS: There exhibited no evident changes of hepatocytic insulin receptor maximal binding capacity and affinity at 3 postburn days (PBDs) in scalded rats. The autophosphorylation capacity of the receptor beta-subunit decreased significantly. And the receptor TPK activity decreased obviously and its reaction to insulin stimulation decreased markedly. CONCLUSION: The defects of the insulin receptor signal transduction in hepatocyte leading to the post-receptor defects of insulin biological effects might be molecular mechanism of postburn insulin resistance.

Animals↗
PubMed2002

Significance of HER-2/neu expression in ovarian epithelial tumours.

OBJECTIVE: To investigate expression of Her-2/neu (c-erbB-2) and its significance in ovarian epithelial tumors. METHODS: 106 specimens and clinical history of ovarian epithelial tumors were collected including 54 cases of malignant, 33 cases of borderline and 19 benign cases. There were 19 cases of stages I and II and 35 cases of stages III and IV in ovarian carcinoma and all borderline malignant cases were stage I according to FIGO's standard. Immunohistochemical staining for Her-2/neu was performed by LSAB method. RESULTS: The positives rates of Her-2/neu of benign, borderline and malignant tumors were 47.4% (9/19), 84.8% (28/33,), and 85.2% (46/54), respectively. Both borderline and malignant cases were found to have higher expression of Her-2/neu than those of benign cases (P < 0.02 and P < 0.01) respectively. Overexpression of Her-2/neu showed in 14/54 (25.9%) of malignant cases, 3/33 (9.1%) of borderline, and none of benign cases. Overexpression of Her-2/neu in malignant tumors cases with metastasis was higher than those without metastasis (P < 0.001). CONCLUSION: Overexpression of Her-2/neu is associated with biological aggressiveness of ovarian cancer.

Female↗
PubMed2002

[Establishment and biological characteristics of human multiple myeloma cell line CZ-1].

OBJECTIVE: To establish a multiple myeloma (MM) cell line and analyze its biological characteristics. METHODS: Mononuclear cells isolated from the peripheral blood (PB) and bone marrow (BM) of an advanced MM patient (lambda light chain type) were incubated by liquid cell culture, cell morphology was analyzed by Wright-Giemsa-staining and cytochemical staining, immunophenotyping by flow cytometry, cytogenetic analysis by chromosome RHG-banding method. Quantitative fluorescent polymerase chain reaction was used to detect EBV DNA. RESULTS: The established cell line could survive and proliferate in the presence of feeder cells or conditioned medium. The cells secreted lambda light chain and were negative for EBV. The Wright-Giemsa-staining showed typical plasmablast or plasma cell morphology. The cytochemical staining of the cells showed the following reactivity pattern: positive for acid phosphatase, negative for myeloperoxidase. The immunoprofile of the cells was concordant with that of MM cells: positive for CD(10), CD(28), CD(38), CD(138), CD(56), CD(49d), CD(44), CD(54) and CD(58), negative for CD(19), CD(40), CD(95), CD(95)L, CD(34), CD(2) and CD(5). The cytogenetic analysis showed complex chromosome abnormality of i (1q +), 8q +, 13q +, i (17q), i (18q) and + M. There was no difference in morphology, immunophenotype and cytogenetics between cells from PB and BM. CONCLUSION: A MM cell line secreting lambda light chain named CZ-1, was established. The cells from both PB and BM have the same biological characteristics.

Antigens, CD↗
PubMed2002

[Expression of vascular endothelial growth factor and its receptors in endometrial carcinoma].

OBJECTIVE: To study the expression of vascular endothelial growth factor (VEGF) and its receptors, the fms-like tyrosine-1 (flt-1) and kinase insert domain-containing receptor (KDR) in endometrial carcinoma and investigate the functions of VEGF and its receptors for endometrial carcinoma angiogenesis and its relation to the grade of tumor. METHODS: Immunocytochemistry and in situ hybridization technique were used to measure the level of VEGF, flt-1, KDR protein and mRNA in endometrial carcinoma tissue from 23 patients and endometrial samples from 6 normal menopausal women. A few endometrial carcinoma samples were homogenized for Western blot analysis. The blood vessel density was estimated by counting blood vessels stained with endothelial marker VIII factor. RESULTS: The VEGF and its receptors were widely expressed in the cytoplasm of endothelial cells and tumor cells of endometrial carcinoma. The level of VEGF protein in endothelial cells and endometrial cancer cells of grade II and III tumor tissues was higher than that in grade I and normal menopausal endometrium (P < 0.05). VEGF mRNA did not show higher expression with the increase of tumor grade but its expression in normal tissue was lower than that in cancer (P < 0.05). The expression of flt-1 protein and mRNA in endothelial cells got higher in III than in grade II and I (P < 0.05), but invariable in cancer cells (P > 0.05), flt-1 expression in cancer was higher than that in normal menopausal endometrium either in endothelial cells or in cancer cells (P < 0.05). The expression of KDR protein in endothelial and cancer cell was high but did not alter with the increase of tumor grade (P > 0.05), the level of its mRNA was higher in cancer than that in normal tissue (P < 0.05). The microvascular density in grade III (48 +/- 12) was higher than that in grade II (26 +/- 16), grade I (27 +/- 14) and normal menopausal tissue (26 +/- 11, P < 0.05). CONCLUSIONS: The expression pattern of VEGF, flt-1 and KDR protein and mRNA increased with the increase of tumor grade in endometrial carcinoma indicates that VEGF and its receptors contribute to the neovascularization of tumors and is one of the factors that relate to rapid tumor growth of endometrial carcinoma.

Endometrial Neoplasms↗
PubMed2002

[Anti-tumor effect through human endostatin gene transfer in mice bearing B16 melanoma].

OBJECTIVE: To investigate the effects of direct intratumor injection of the packaged cells with retroviral vector carrying human endostatin (hEN) on the growth inhibition of B16 melanoma in C57/BL6 mice. METHODS: Retroviral vector, pLNC-hEN, was constructed with modified and identified hEN gene. The cell line, PA317, was used to establish ecotropic virus producing cells by transfecting and packing with pLNC-hEN. Then the cells were injected directly into the tumor in C57/BL6 mice bearing B16 melanoma, established by intra-cutaneous injection of B16 cell suspension. The tumor size was measured at different intervals to observe the antitumor effect. Micro-vessel density (MVD) in the tumor tissue was evaluated by immunohistological examination to count the apoptotic cells by TUMEL staining. RESULTS: Tumor with diameter of 2 - 3 mm was observed in all mice after 7 - 9 days. The average tumor volume on D3, D5, D7 and D9 after gene transfection was 4.67 +/- 1.1, 22.25 +/- 13.06, 84.17 +/- 43.5 and 155.08 +/- 81.1 mm(3) in the gene therapy group but 136.17 +/- 30.61, 390.17 +/- 220.47, 1 021.67 +/- 537.4 and 2 920.2 +/- 220.01 mm(3) in the control group, the difference of which was statistically significant. The average MVD in the gene therapy and control groups were 8 +/- 2.28 and 28.17 +/- 5.31 while the average apoptotic cell number in the two groups were 23.33 +/- 3.83 and 2.33 +/- 1.21, both of which were statistically significant. CONCLUSION: The direct injection of packaged cells carrying hEN gene is able to inhibit the growth of micro-blood vessels and promote tumor cell apoptosis, which ultimately inhibits the growth of B16 melanoma.

Angiogenesis Inhibitors↗
PubMed2002

[Cloning and expression of heavy chain variable region genes against telomerase protein hTERT].

Single domain antibodies against telomerase protein hTERT were prepared by technique of displayed on the surface of recombinant bacterio phages. Total RNA of spleen lymphocytes were extracted from mice immunized recombinant hTERT and transcripted to cDNA. First-strand cDNA was used as a template, heavy chain variable region genes against hTERT were amplified with VHfor and VHback primers by PCR technique. Amplification reaction yielded a fragment about 350 base pairs in length. Amplified cDNA were cloned into the vehide of bacteriophage PCANTAB 5E, the phagemid containing VH gene transformed into competent E. coli TG1, in the presence of helper phage M13K07, VH-g3 fusion proteins were display on the surface of recombinant phages. The phage carrying VH genes that encode binding activities could be detected directly with DOT BLOT. Single domain antibodies were generated successfully and had binding activities with hTERT. Results suggest that phage display technique be a new way of making antibodies. VH genes were cloned successfully, which could provide possibility for futher preparing single-chain antibodies(ScFv) anti-hTERT.

Animals↗