[Expression of lipofect AMINE mediated human GM-CSF eukaryotic expressing vector in HFCL cells]

OBJECTIVE

To construct an eukaryotic expressing vector-pIRES1neo/hGM-CSF and express it in human bone marrow stromal cell line HFCL.

METHODS

Human granulocyte/macrophage colony-stimulating factor cDNA (hGM-CSF cDNA, 751 bp) was inserted into an effective eukaryotic expressing vector-pIRES1neo which contains the human cytomegalovirus (CMV) major immediate early promoter/enhancer and the internal ribosome entry site (IRES) of the encephalomyocarditis virus (ECMV). HFCL cells were transfected with the recombinant vector pIRES1neo/hGM-CSF by liposome-mediated gene transfer method. Integration of hGM-CSF in the genome, transcription of its mRNA and expression of its protein in the transfected HFCL cells were assayed by Southern blot, Northern blot, ELISA and hGM-CSF dependent cell line TF-1.

RESULTS

hGM-CSF cDNA was integrated into HFCL genome successfully, hGM-CSF mRNA was transcripted and hGM-CSF protein was expressed of (56.9 +/- 0.7) ng/10(6) cells by ELISA and (6.56 +/- 0.16) x 10(3) U/10(6) cells per day by TF-1 cell assay in the supernatant.

CONCLUSION

The recombinant vector is proved to be stably expressed in HFCL cells and the biological activity of hGM-CSF was detectable in the supernatant of the transfected cells.

[Experimental studies on the characteristics of suicide gene system HSV-tk/GCV and its effect on dendritic cells]

OBJECTIVE

To study the characteristics of suicide gene system of the herpes simplex virus thymidine kinase (HSV-tk) gene in tumor cells and explore the apoptosis phenomena in this system and its effect on dendritic cells (DC).

METHOD

HSV-tk was transduced into the breast cancer cell line MCF-7 cells with a retrovirus vector. Apoptosis was examined by electro-microscopy and FACS. DCs were induced from cord blood CD(34)(+) cells with a combination of cytokines (GM-CSF, TNF-alpha, SCF and FL) and (3)H-TdR was adopted to determine the proliferation of T cells.

RESULTS

In vitro experiment showed a dose-dependent cell killing of the HSV-tk gene transducted cells on ganciclovir (GCV) treatment. The apoptosis rate increased to 31.3% from the control group of 19.3%. Apoptosis is the important mechanism in bystander effect of HSV-tk/GCV system. The CD(1a)(+) and HLA-DR(+) cells in the induced DC were of (27.18 +/-1.56)% and (93.7 +/- 1.0)%, respectively. Co-incubation of DC with apoptotic cells further stimulated the proliferation of T cells.

CONCLUSION

It suggested that HSV-tk/GCV system, alone or combined with radiotherapy, be a promising suicide gene therapy for cancer patient and an approach to enhancing DC function.

[The first discovery of endemic Lyme disease in Shandong province]

OBJECTIVE

To investigate the endemic area of Lyme disease in Shandong province.

METHODS

An investigation on endemic Lyme disease was conducted by means of serological and etiological methods in Shandong province from 1992 to 1999.

RESULTS

Of 1919 forestry residents, 120 residents had a significant antibody titer against Borolo burgdorferi strain B(31). The prevalance rate of Lyme disease was 6.25%. Haemaphysalis longicornis was a prevailing species of Ixodidae in the region. Spirochetes were observed in the midguts of 50 H. longicornis in this area by direct fluorescence antibody method. The overall positive rate was 12.0% (6/50). Two strains (TSH(1), TSH(3)) of spirochetes were isolated from H. longicornis. Both TSH(1) and TSH(3) were positively responded to McAb H(5332) and H(9724), but negatively to H(6831). Spirochetes were observed in the kidneys of 46 Rattus in this area by direct fluorescence antibody method with a positive rate of 13.26% (6/46).

CONCLUSION

It was the first time that the mountainous areas in Shandong province was confirmed endemic areas of Lyme disease.

Neurocan is a heparin binding proteoglycan

Neurocan and brevican are related chondroitin sulfate proteoglycans which are mainly expressed in the central nervous system. Neurocan and the secreted brevican variant are composed of globular N-terminal hyaluronan binding domains, central O-linked oligosaccharide attachment regions, and globular C-terminal domains. Interaction studies of mouse brain proteoglycans revealed that neurocan, but not brevican, was retained on a heparin affinity matrix. Also a recombinantly produced C-terminal fragment of neurocan, expressed by HEK 293 cells, was retained by the heparin affinity matrix. The substitution of this fragment with a chondroitin sulfate chain did not inhibit binding to the heparin affinity matrix at physiological NaCl concentrations, but decreased the NaCl concentration necessary for elution. Two potential consequences of the heparin binding ability of neurocan are an enforcement of the interaction with other heparin binding molecules and a directed secretion by polarized cells.

[Clinical analysis of glucose dysbolism in 162 cases with Cushing syndrome]

OBJECTIVE

To understand the characteristic of steroid diabetes by the analysis for clinical data of 162 cases with Cushing syndrome (CS) proved by pathological report.

METHODS

Retrospective analysis for the data of CS about age of CS onset, duration of CS, body mass index (BMI), 24 hours urine free cortisol (24 h UFC), pathological report, fasting blood glucose (FBG) pre- and post-operation, family history of diabetes, treatment of glucose dysbolism (GD) pre- and post-operation.

RESULTS

The onset age and duration of CS in GD group was obviously earlier and longer than normal glucose (NG) group. BMI and 24 h UFC were no difference between two groups. Besides adrenal adenocarcinoma, no difference was found in types of pathology. FBG of diabetes pre-operation was obviously lower than post-operation. After operation, most diabetes need not on drug treatment. Only one secondary diabetes has family history.

CONCLUSIONS

Steroid diabetes easily occurs in patients who is senility and suffer longer course of CS. No relation to diabetic family history, concentric obesity, the level of UFC and benign types of pathology. Therapeutical emphasis of steroid diabetes is radical cure of CS.

[Effects of hypoxia on the proliferation and differentiation of CD34(+) hematopoietic stem/progenitor cells and their response to cytokines]

To elucidate the effects of hypoxia on the proliferation and differentiation of CD34(+) hematopoietic stem/progenitor cells and their response to cytokines, the cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS). Mononuclear cells (MNC) and CD34(+) cells were incubated in severe hypoxia (1% oxygen) culture system, and the colony forming cells and antigen expression were studied by colony forming assays and FACS analysis. The results showed that incubation in severe hypoxia increased the number of erythroid bursts (BFU-E) (324.8+/-41.4/10(4) cells) generated from CD34(+) cells (191.2+/-34.5/10(4) cells in the control group, P<0.01). Severe hypoxia also enhanced the maintenance and cloning efficiency of BFU-E in a liquid culture system without growth factors, the number of BFU-E (152.4+/-22.6/10(4)cells) was much bigger than that in the control group (74.2+/-9.3/10(4) cells, P<0.01). In cultures incubated in hypoxia, the percentage of CD34(+) cells was significantly higher (2.5+/-1.2-fold, P<0.05) than in those incubated in air. BFU-E cloning efficiency of MNC was not significantly affected by hypoxia. The above results show that hypoxia enhances the maintenance of erythroid progenitor cells generated from CD34(+) hematopoietic stem/progenitor cells, no matter growth factors are present or not. These positive effects of hypoxia did not occur for the other progenitors.

[Expression of MAGE-3 gene product in non-small cell lung cancer]

OBJECTIVE

To study the expression of MAGE-3 antigen in non-small cell lung cancer (NSCLC).

METHODS

The expression of MAGE-3 antigen was examined in formalin fixed, paraffin embedded sections of NSCLC by LSAB immunohistochemical technique.

RESULTS

MAGE-3 antigen was detected in 31 of 104 (29.8%) patients with primary NSCLC. The frequency of MAGE-3 expression was significantly correlated to the absence of metastasis (P < 0.05) and better survival rate (P < 0.01). There was no significant relationship between MAGE-3 expression and histological type of NSCLC.

CONCLUSION

MAGE-3 antigen expression in NSCLC correlates with better prognosis. It is a candidate molecular target for specific immunotherapy for NSCLC patients.

[Retroviral-mediated transfer of a hygromycin phosphotransferase-thymidine kinase fusion gene into human bladder carcinoma cell]

OBJECTIVE

To evaluate the therapeutic efficacy of retroviral-mediated hygromycin phosphotransferase-thymidine kinase fusion gene (HyTK)/GCV on human bladder carcinoma cell.

METHODS

A retroviral expression vector pL (HyTK) SN was constructed. By using FuGENE 6-mediated transfection and "ping-pong effect" technique, high-titer of retroviral supernatant was obtained and HyTK gene was transferred into EJ cells. A retroviral vector encoding, enhanced green fluorescent protein, EGFP was used to rapidly detect the transduction efficiency. Antitumor effects were observed after GCV treatment.

RESULTS

In vitro experiments demonstrated the EJ cells transferred by HyTK gene were killed in the GCV treatment. Non-transduced parental cells were not sensitive to GCV, but they were dead by the bystander killing of neighboring cells when mixed with EJ/HyTK cells at various ratios. In addition, this not only affect wild-type EJ cells but also cells from different bladder carcinoma cell lines.

CONCLUSIONS

Retroviral-mediated HyTK/GCV systems were a promising suicide gene therapy for bladder carcinoma. EGFP may act as a convenient and rapid reporter to monitor retroviral-mediated gene transfer and expression in bladder carcinoma cells.

[Engineering of hematopoietic cells and the hematopoietic reconstitution of expanded cells in SCID mice]

OBJECTIVE

To elucidate the roles of cytokines for ex vivo expansion and orderly differentiation of hematopoietic progenitor cells, and the capacity of hematopoietic reconstitution of the expanded cells.

METHODS

CD34+ cells were isolated from umbilical cord blood by using a high-gradient magnetic cell sorting system (MACS), and expanded with the different combinations of cytokines in a liquid culture system. The expanded cells were then transplanted into sublethally irradiated SCID mice.

RESULTS

The combination of cytokines including FL, SCF, TPO, etc. increased total cells, progenitor cells(CFU-GM and CFU-MK), and CD34+ CD38- early progenitor cells by (2,130 +/- 57), (70 +/- 7), (118 +/- 11) and (46 +/- 5) folds, respectively. The percentage of dendritic cells (24.3 +/- 2.1)% was also much higher than the control(0.4 +/- 0.3)%. The CD34+ CD38- subsets and the combination of FL and TPO were identified as the most potential for expanding early progenitor cells. The expanded cells could smoothly engraft SCID recipients and reconstitute their hematopoiesis. Furthermore, human hematopoietic cells and could be detected in marrow cells from SCID mice transplanted 6 weeks late.

CONCLUSIONS

It is possible to expand hematopoietic cells ex vivo efficiently and maintain the hematopoietic reconstitution capacities of hematopoietic stem/early progenitor cells by an appropriate combination of cytokines. The engineering of hematopoietic cells--the new generation of cellular therapeutics are now underway in the applications of stem cell transplantation, immunotherapy of cancers, and gene therapy.

Mouse ten-m/Odz is a new family of dimeric type II transmembrane proteins expressed in many tissues

The Drosophila gene ten-m/odz is the only pair rule gene identified to date which is not a transcription factor. In an attempt to analyze the structure and the function of ten-m/odz in mouse, we isolated four murine ten-m cDNAs which code for proteins of 2,700-2, 800 amino acids. All four proteins (Ten-m1-4) lack signal peptides at the NH2 terminus, but contain a short hydrophobic domain characteristic of transmembrane proteins, 300-400 amino acids after the NH2 terminus. About 200 amino acids COOH-terminal to this hydrophobic region are eight consecutive EGF-like domains. Cell transfection, biochemical, and electronmicroscopic studies suggest that Ten-m1 is a dimeric type II transmembrane protein. Expression of fusion proteins composed of the NH2-terminal and hydrophobic domain of ten-m1 attached to the alkaline phosphatase reporter gene resulted in membrane-associated staining of the alkaline phosphatase. Electronmicroscopic and electrophoretic analysis of a secreted form of the extracellular domain of Ten-m1 showed that Ten-m1 is a disulfide-linked dimer and that the dimerization is mediated by EGF-like modules 2 and 5 which contain an odd number of cysteines. Northern blot and immunohistochemical analyses revealed widespread expression of mouse ten-m genes, with most prominent expression in brain. All four ten-m genes can be expressed in variously spliced mRNA isoforms. The extracellular domain of Ten-m1 fused to an alkaline phosphatase reporter bound to specific regions in many tissues which were partially overlapping with the Ten-m1 immunostaining. Far Western assays and electronmicroscopy demonstrated that Ten-m1 can bind to itself.

[Role of paraventricular nucleus in pressor response induced by dorsol part of midbrain periaqeductal gray stimulation]

Experiments were carried out on male SD rats anesthetized with urethane (700 mg/kg) and chloralose (35 mg/kg). The results were as follows: (1) The pressor response could be elicited by electrical stimulation of dorsol part of midbrain periaqueductal gray (dPAG) for 5 s every 5 min. The pressor response for each series of dPAG stimulation within 50 min was constant. This pressor response could be decreased by electrolytic cauterization of paraventricular (PVN) area, but unaffected by electrolytic lesion of fornix, anterior hypothalamic area, nucleus dorsomedialis hypothalami and nucleus ventromedicalis hypothalami. (2) Microinjection of an AVP-V1 receptor antagonist (CH2)5 [Tyr(Me)2AVP] (each side 0.1 nmol/0.1 microliter) into the bilateral rostral ventrolateral medulla (rVLM) partially inhibited the pressor response induced by PVN stimulation or by microinjection of D,L-homocysteric acid (DLH) (0.1 mol/0.2 microliter) into the PVN, but the mean artrtial pressure (MBP) and heart rate (HR) did not show any change when an AVP-V1 receptor antagonist or DLH was only used. (3) Microinjection of an AVP-V1 receptor antagonist into the bilateral rVLM partially inhibited the pressor response induced by dPAG stimulation. Therefore it is suggested that the effect of vasopression (AVP) released from PVN on the pressor response induced by dPAG stimulation is partly mediated by activation of AVP-V1 receptor in the rVLM.

[Epidemiological features of human brucellosis in the rural areas in Shandong during 1990-1996]

Epidemiologic features of Brucellosis in the rural areas in Shandong in the 90's were studied and analysed by means of epidemiological and statistical methods. Results indicated an increasing trend in incidence of the disease (Trend tast: chi 2 = 76.06, P < 0.01). Cases mainly concentrated in few economically poor regions connecting Jinan, Zibo, Binzhou and Weifang cities or prefectures. The patients showed serious and classical clinical symptoms. More cases under 14 years and over 60 years old were seen than before. The epidemic peak has been advanced with the epidemic strain B. melti. III identified. Mismanagement on animal quarantine, eradication of infected animals and vaccination in those poor areas accounted for the major reasons of the recurrence.

[Effect of vasopressin in the rostral ventrolateral medulla on pressor response induced by dPAG stimulation]

Experiments were performed on male SD rats anaesthetized with urethane (700 mg/kg) and chloralose (35 mg/kg). The results showed that mean arterial pressure (MBP) increased signifigantly and heart rate (HR) had no signifigant change by bilateral microinjection AVP(10 pmol/0.1 microliter/site) into the rostral ventrolateral medulla (rVLM), while both MBP and HR were not changed by application of an AVP-V1 receptor antagnoist. Microinjection of an AVP-V1 receptor antagonist into the bilateral rVLM inhibited partially the pressor response induced by midbrain defence area stimulation. The above results suggest that AVP in the rVLM can elevate MBP and midbrain defence area stimulation can cause pressor response. Both these effects are related to activation of AVP-V1 receptors in the rVLM.

Photochemical reactions of azidocoumarins

Photochemical reactions of 6-azidocoumarin and 7-azido-4-methylcoumarin in the presence of secondary amines have been investigated for their potential applications in photoaffinity labeling. It was found that the singlet nitrene generated from 6-azidocoumarin isomerized to a dehydroazepine intermediate that reacted with an amine to yield two isomeric adducts. Photolysis of 7-azido-4-methylcoumarin, in contrast, gave a triplet nitrene that abstracted hydrogen atoms from secondary amine molecules to form 7-amino-4-methylcoumarin as the major product. The difference in the intersystem crossing rate between the two compounds originates from the azido position relative to the carbonyl group. Because of its ability to form a covalent linkage with a nucleophile, 6-azidocoumarin is deemed to have a greater potential as a photoaffinity label than 7-azido-4-methylcoumarin.

[Detection of P-glycoprotein expression in patients with acute leukaemia and clinical significance]

Anti-P-glycoprotein monoclonal antibody JSB-1 and alkaline phosphatase-anti-alkaline phosphatase (APAAP) immunocytochemical staining technique were used to study the relation between P-glycoprotein expression and clinical multidrug resistance (MDR) in 42 patients with acute leukaemia (23 ALL and 19 ANLL). 10 of 17 patients who were diagnosed as refractory or relapsed acute leukaemia were positive with P-glycoprotein expression, while only 3 of 14 newly diagnosed and 1 of 11 who were in complete remission were positive. The preliminary results indicated that there was a close association between the P-glycoprotein expression and the clinical resistance to chemotherapy in some patients.

[Screening of anti-inflammatory, immunosuppressive and antifertility components of Tripterygium wilfordii V. Effects of 7 diterpene lactone epoxide compounds on the proliferation of T and B lymphocytes in vitro]

The inhibitory effects and their IC50 values of Tripterygium wilfordii (TW) on T and B lymphocytes were assayed using mice splenocytes induced to proliferate by mitogens ConA and LPS in vitro. The results indicated that 6 compounds (T4,T7,T8,T9,T10,L2) and component T1 had significant inhibitory effects on the proliferation of lymphocytes in response to ConA and LPS. The inhibitory potencies of these compounds were in the range of 10(-5)-10(-9) micrograms/ml for both T and B cells, while those of T1 were 3.5 and 4.2 micrograms/ml, respectively. The IC50 values, from low to high, were in the following order: T10,T4,T8,L2,T7,T9 and T1, The dose-effect curves for LPS were to the right of ConA curves, though both were nearly parallel. The relative order of the IC50 values determined from ConA and LPS curves were also coincident. Another compound, T11, showed no suppressive effect on the proliferation of T and B lymphocytes induced by either mitogen, even when its concentration reached 50 micrograms/ml. The results suggest that the suppressive effects of the componends on the proliferation of T and B lymphocytes in vitro were direct and non-selective.