[Cell cycle G2 arrest, cell death and nuclear localization induced by human immunodeficiency virus type 1 protein R (VPR) in cervical cancer cells]

OBJECTIVE

To explore the possibility of using Vpr as a biological agent for anticancer therapy.

METHODS

A HIV-1 wild type Vpr and a mutant VprX gene were expressed and tested in a cervical cancer HeLa cell line. The ability of Vpr to induce cell cycle G2 arrest and cell death was measured by flow cytometric analysis. Nuclear localization of Vpr was visualized by fluorescent light emitted from the green fluorescent protein (GFP) -Vpr fusion protein.

RESULTS

Consistent with early reports, Vpr, not VprX, induced G2 arrest. However, both Vpr and VprX were able to induce cell death in HeLa cells. We also demonstrated that the nuclear localization of Vpr could be determined by using a GFP-Vpr fusion protein.

CONCLUSIONS

This is the first report documenting in mammalian cells that G2 arrest and cell death induced by Vpr are two independent functions. The unique biological properties of Vpr shown in cervical cancer cells suggest that Vpr may be a useful biological agent for anti -cancer therapy.

Chemokine signaling and HIV-1 fusion mediated by macrophage CXCR4: implications for target cell tropism

To better understand CXCR4 function on macrophages and the relationship between coreceptor use and macrophage tropism among diverse HIV-1 isolates, we analyzed macrophage pathways involved in Env-mediated fusion, productive HIV-1 infection, and chemokine-elicited signaling. We found that both CXCR4 and CCR5 transduced intracellular signals in monocyte-derived macrophages, activating K+ and Cl- ion channels and elevating intracellular calcium in response to their chemokine ligands stromal cell-derived factor-1alpha and macrophage inflammatory protein-1beta, respectively. The prototype T-tropic X4 strain IIIB infected macrophages poorly, and this was associated with failure of the IIIB Env to fuse efficiently with target macrophages despite functional CXCR4. In contrast, several primary X4 isolates mediated efficient CXCR4-dependent fusion and productive macrophage infection. Several R5X4 strains could fuse with and infect macrophages through both CCR5 and CXCR4. Thus, macrophages express functional CXCR4 and CCR5 but primary and prototype X4 isolates differ in their ability to utilize macrophage CXCR4. Isolates classified as X4 based on coreceptor use may be phenotypically either T-tropic or dual-tropic and, conversely, phenotypically dual-tropic isolates may be either R5X4 or X4 based on coreceptor use.

Co-receptor usage was more predictive than NSI/SI phenotype for HIV replication in macrophages: is NSI/SI phenotyping sufficient?

A monocyte-derived macrophage (MDM) culture assay was used to define the replication kinetics of HIV isolates. Ten-day-old MDMs were infected with HIV. Supernatants were collected and assayed for HIV p24 on days 3, 7, 10, and 14 post-infection (PI). In this assay, SF162 (macrophage tropic, NSI) produced increasing amounts of HIV p24 antigen with increasing time in culture. BRU (nonmacrophage tropic, SI) infection resulted in low levels of HIV p24 antigen with no increase in production during the culture period. A panel of 12 clinical isolates was evaluated. All isolates produced detectable levels of HIV p24 antigen in MDMs. However, the NSI viruses had significantly higher log10 HIV p24 antigen values at all times PI (P < 0.01). Co-receptor usage was determined for all 12 isolates (8 NSI and 4 SI). All SI isolates used CXCR4 for entry; two used CXCR4 only, one used CXCR4, CCR5, and CCR3, and one was a mixture of two isolates using CXCR4 and CCR5. None of the NSI viruses used CXCR4 for entry. All used CCR5 as their predominant co-receptor. Of the eight NSI isolates, three used CCR5 only, two used CCR5 and CCR2b, one used CCR5 and CCR3, and one used CCR5, CCR3, and CCR2b. Log10 HIV p24 antigen production on day 14 PI for viruses that used CCR5+CCR3 (3.79 + 1.40) was greater than for viruses that used CCR5+CCR2b (3.22 + 1.55) or CCR5 (3.32 + 1.49), and all were greater than those that used CXCR4 only (1.69 + 0.28), regardless of SI phenotype (P < 0.05). Thus, in these primary isolates, macrophage tropism and replication kinetics were closely linked to CCR5 utilization, whereas SI capacity was closely linked to CXCR4 utilization. Furthermore, viruses, which could use CCR5 and CCR3 for entry, had a replication advantage in macrophages, regardless of SI phenotype.

Neuroprotective activity of tiagabine in a focal embolic model of cerebral ischemia

Gamma aminobutyric acid (GABA) agonists have been shown to have neuroprotective effects when used after focal or global cerebral ischemia. In this study, we evaluated the neuroprotective effects of a GABA re-uptake inhibitory agent, tiagabine, on focal ischemic brain injury in an embolic model in rats. Tiagabine, injected at 1 h after embolization, significantly reduced brain infarction volume, measured with 2,3,5-triphenyltetrazolium chloride (TTC) histological assay. There were varying degrees of neuroprotective effect exhibited in the other experimental groups however this did not reach significance. These results suggest that tiagabine is neuroprotective when administrated at an early period after the ischemic brain injury.

[Study of the distribution feature of the endocrine cells of human islet and its relation to microvasculature]

Double immunohistochemical stain was used for the study of distribution feature of the endocrine cells of human islets and its relation to the microvasculature. The results were as follows (1) Sheath islet was found in human adult islets and the B cells situated the central part of the islets and arrounding it were the A and D cells which formed the sheath of the islets. (2) The identical distribution of the A and D cells was found. (3) Some islets were divided into several "subunite" by connective tissue in which the B cells and A(or D) cells situated the central and peripheral part respectively. (4) The A and D cells were near the microvasculature. These results will provide morphologic basis for the research of the functional relation among the endocrine cells.

Pediatric intractable epilepsy: the role of presurgical evaluation and seizure outcome

Surgical experience with long-term follow-up is limited in childhood intractable epilepsy, compared with adult epilepsy. To assess the role of each presurgical evaluation modality and to identify prognostic factors for favorable seizure control after epilepsy surgery, 38 children with intractable epilepsy who underwent surgery were retrospectively reviewed. Among the available preoperative evaluation modalities, PET and neuropsychological testing showed the highest rates of positive results, whereas MRI was the most concordant with EEG findings. During a follow-up period of at least 12 months, 26 of the 38 patients showed favorable seizure control (Engel classifications I and II). The best seizure control was achieved in patients with a temporal resection and discrete lesion on magnetic resonance imaging. In spite of the invasive study, the less satisfactory results followed an extratemporal resection. We conclude that epilepsy surgery benefits children with intractable epilepsy and that the role of invasive study should be reestablished according to the area of resection and presence of discrete lesion on MRI.

Activin receptor-like kinase 1 modulates transforming growth factor-beta 1 signaling in the regulation of angiogenesis

The activin receptor-like kinase 1 (ALK1) is a type I receptor for transforming growth factor-beta (TGF-beta) family proteins. Expression of ALK1 in blood vessels and mutations of the ALK1 gene in human type II hereditary hemorrhagic telangiectasia patients suggest that ALK1 may have an important role during vascular development. To define the function of ALK1 during development, we inactivated the ALK1 gene in mice by gene targeting. The ALK1 homozygous embryos die at midgestation, exhibiting severe vascular abnormalities characterized by excessive fusion of capillary plexes into cavernous vessels and hyperdilation of large vessels. These vascular defects are associated with enhanced expression of angiogenic factors and proteases and are characterized by deficient differentiation and recruitment of vascular smooth muscle cells. The blood vessel defects in ALK1-deficient mice are reminiscent of mice lacking TGF-beta1, TGF-beta type II receptor (TbetaR-II), or endoglin, suggesting that ALK1 may mediate TGF-beta1 signal in endothelial cells. Consistent with this hypothesis, we demonstrate that ALK1 in endothelial cells binds to TGF-beta1 and TbetaR-II. Furthermore, the ALK1 signaling pathway can inhibit TGF-beta1-dependent transcriptional activation mediated by the known TGF-beta1 type I receptor, ALK5. Taken together, our results suggest that the balance between the ALK1 and ALK5 signaling pathways in endothelial cells plays a crucial role in determining vascular endothelial properties during angiogenesis.

Over-expression of ERT(ESX/ESE-1/ELF3), an ets-related transcription factor, induces endogenous TGF-beta type II receptor expression and restores the TGF-beta signaling pathway in Hs578t human breast cancer cells

The epithelium-specific transcription factor, ERT/ESX/ESE-1/ELF3, binds to the TGF-beta RII promoter in a sequence specific manner and regulates its expression. In this study, we investigated whether ERT could regulate endogenous TGF-beta RII expression in Hs578t breast cancer cells. Analyses of the Hs578t parental cell line revealed low RII mRNA expression and resistance to the growth inhibitory effects of TGF-beta. Infection of this cell line with a retroviral construct expressing ERT induced higher levels of endogenous RII mRNA expression and protein expression relative to cells infected with chloramphenicol acetyltransferase (CATneo) as a control. Relative to control cells, the ERTneo-expressing Hs578t cells show approximately a 50% reduction in cell growth in the presence of exogenous TGF-beta1, as well as a fourfold higher induction of activation in transient transfection assays using the 3TP-luciferase reporter construct. When transplanted into athymic mice, ERT-expressing Hs578t cells showed decreased and delayed tumorigenicity compared with control cells. This data strongly suggests that ERT plays an important role as a transcriptional activator of TGF-beta RII expression, and that deregulated ERT expression may play a critical role in rendering Hs578t human breast cancer cells insensitive to TGF-beta's growth inhibitory effects.

[Observation of the endothelial healing in rabbit corneal alkali wounds by alizarin red S-trypan blue staining method]

PURPOSE

To study the healing of the corneal endothelial cells in rabbit corneal alkali wounds.

METHODS

26 New Zealand white rabbits were used. A alkali wound was created with a round filter paper, 8 mm in diameter, which was soaked in 0.5 N NaOH for 5 seconds and was placed centrally on the cornea for 60 seconds. The rabbits were killed in 20 minutes; 1, 2, 6, 12 h; 1, 2, 3, 5, 7, 10, 14, 30 days after injury. The corneal endothelium was examined in the light microscope using a lizarin red S-trypan blue staining method.

RESULTS

Twenty minutes after the wound, the corneal endothelial cells were destroyed. 72 hours following the wound, the endothelial cells surrounding the burns became larger, irregular and started to migrate onto the denuded descemet's membrane. The endothelial cells covered the burn with the spindle-shaped cells 7 days after wound.

CONCLUSION

The endothelial damage is healed by the division and migration of remaining endothelial cells at the margin of the wound, which has some characters of fibroblast.

Changes of nailfold microcirculation in patients of type II diabetes mellitus with diabetic retinopathy

OBJECTIVE

To study the changes of microcirculation in patients with diabetic retinopathy (DR).

METHODS

Examination were performed in 153 cases of type I diabetes mellitus, among them, 72 cases were male, 81 cases were female, mean age 57.0+/-10.0 years, mean disease course 8.2+/-7.5 years. All cases were examined fundi by ophthalmologist, urinary albumin excretion rate (UAE) in 24 hours was measured by radioimmunoassay. Moreover, we examined the blood glucose, blood pressure, blood viscosity and observed the changes of naifold microcirculation.

RESULTS

It was found that there were more evident disturbance of microcirculation, markedly slowed velocity of blood flow (P<0.05), significantly increased aggregation of blood cells (P<0.05) and exudation around the loop (P<0.05) in the group with DR, compared with the group without DR.

CONCLUSION

It was more evident disturbance of nailfold microcirculation in patients with diabetic retinopathy.

Role of CXCR4 in cell-cell fusion and infection of monocyte-derived macrophages by primary human immunodeficiency virus type 1 (HIV-1) strains: two distinct mechanisms of HIV-1 dual tropism

Dual-tropic human immunodeficiency virus type 1 (HIV-1) strains infect both primary macrophages and transformed T-cell lines. Prototype T-cell line-tropic (T-tropic) strains use CXCR4 as their principal entry coreceptor (X4 strains), while macrophagetropic (M-tropic) strains use CCR5 (R5 strains). Prototype dual tropic strains use both coreceptors (R5X4 strains). Recently, CXCR4 expressed on macrophages was found to support infection by certain HIV-1 isolates, including the dual-tropic R5X4 strain 89.6, but not by T-tropic X4 prototypes like 3B. To better understand the cellular basis for dual tropism, we analyzed the macrophage coreceptors used for Env-mediated cell-cell fusion as well as infection by several dual-tropic HIV-1 isolates. Like 89.6, the R5X4 strain DH12 fused with and infected both wild-type and CCR5-negative macrophages. The CXCR4-specific inhibitor AMD3100 blocked DH12 fusion and infection in macrophages that lacked CCR5 but not in wild-type macrophages. This finding indicates two independent entry pathways in macrophages for DH12, CCR5 and CXCR4. Three primary isolates that use CXCR4 but not CCR5 (tybe, UG021, and UG024) replicated efficiently in macrophages regardless of whether CCR5 was present, and AMD3100 blocking of CXCR4 prevented infection in both CCR5 negative and wild-type macrophages. Fusion mediated by UG021 and UG024 Envs in both wild-type and CCR5-deficient macrophages was also blocked by AMD3100. Therefore, these isolates use CXCR4 exclusively for entry into macrophages. These results confirm that macrophage CXCR4 can be used for fusion and infection by primary HIV-1 isolates and indicate that CXCR4 may be the sole macrophage coreceptor for some strains. Thus, dual tropism can result from two distinct mechanisms: utilization of both CCR5 and CXCR4 on macrophages and T-cell lines, respectively (dual-tropic R5X4), or the ability to efficiently utilize CXCR4 on both macrophages and T-cell lines (dual-tropic X4).

Preferential coreceptor utilization and cytopathicity by dual-tropic HIV-1 in human lymphoid tissue ex vivo

Many HIV-1 isolates at the late stage of disease are capable of using both CXCR4 and CCR5 in transfected cell lines, and are thus termed dual-tropic. Here we asked whether these dual-tropic variants also use both coreceptors for productive infection in a natural human lymphoid tissue microenvironment, and whether use of a particular coreceptor is associated with viral cytopathicity. We used 3 cloned dual-tropic HIV-1 variants, 89.6 and its chimeras 89-v345.SF and 89-v345.FL, which use both CCR5 and CXCR4 in transfected cell lines. In human lymphoid tissue ex vivo, one variant preferentially used CCR5, another preferentially used CXCR4, and a third appeared to be a true dual-tropic variant. The 2 latter variants severely depleted CD4(+) T cells, whereas cytopathicity of the virus that used CCR5 only in lymphoid tissue was mild and confined to CCR5(+)/CD4(+) T cells. Thus, (a) HIV-1 coreceptor usage in vitro cannot be unconditionally extrapolated to natural microenvironment of human lymphoid tissue; (b) dual-tropic viruses are not homogeneous in their coreceptor usage in lymphoid tissue, but probably comprise a continuum between the 2 polar variants that use CXCR4 or CCR5 exclusively; and (c) cytopathicity toward the general CD4(+) T cell population in lymphoid tissue is associated with the use of CXCR4.

Differentiation of embryonic stem cells into neurons and retina-like structure in nude mice

PURPOSE

To investigate the intraocular growth and biological characteristics of mice embryonic stem cells in nude mice.

METHODS

Murine embryonic stem cells (D3 cell line) were cultured and maintained in an undifferentiated state in vitro, then transplanted into the anterior chamber of nude mice. Mophological and immunohistochemical examinations were implemented.

RESULTS

Two to three days after transplantation, yellow-white floating granules, sheets and masses were seen inside the anterior chamber and vitreous cavity, and enlarged gradually. 14-20 days later, the mice were executed. Morphological examination showed that there were undifferentiated cells and some round or polygonal differentiated cells in anterior chamber and vitreous cavity. The morphology of these differentiated cells were similar to that of the retina. The cells were highly positive in NSE staining.

CONCLUSION

The transplanted embryonic stem cells could grow in the eyes of nude mice with tendency to differentiate into neurons and retina-like structure.

A macrophage fusion assay for rapid screening of cloned HIV-1 Env using dual recombinant vaccinia viruses expressing distinct RNA polymerases

HIV-1 cell tropism is determined initially at the level of fusion mediated by the viral envelope glycoprotein (Env). Cell-cell fusion assays are employed widely to study Env-mediated fusion, and generally require transfection of target cells with a reporter plasmid that is activated upon fusion with Env-expressing effector cells. Macrophages are an important target for HIV-1, but fusion studies using primary macrophages are limited by their resistance to transfection. An assay described previously used recombinant vaccinia virus to express T7 polymerase in macrophages, and effector cells transfected with a T7-driven reporter plasmid and infected with recombinant vaccinia virus expressing Env. However, this requires a recombinant vaccinia virus for each Env. We developed a method to study fusion using primary macrophages and HIV-1 env plasmid clones under control of the T7 promoter. Macrophages were infected with a recombinant vaccinia virus expressing the SP6 RNA polymerase. Effector 293T cells were infected with a recombinant vaccinia virus expressing T7 polymerase, and co-transfected with T7-driven env plasmids and an SP6-driven reporter gene plasmid. Cell-cell fusion mediated by T7-driven Env results in SP6-driven reporter gene transactivation. This approach is suitable for rapid analysis of multiple primary isolate, chimeric, or mutant env genes cloned into plasmid vectors.

Effects of topical corticosteroids on inflammatory mediator-induced eicosanoid release by human airway epithelial cells

BACKGROUND

Airway epithelial cells are among the first cells to come in contact with aerosolized corticosteroids. However, the relative potencies and time course of action of the several commonly used aerosolized corticosteroids on eicosanoid production by airway epithelial cells are unknown.

OBJECTIVES

This study compared the effects of fluticasone, budesonide, and triamcinolone on eicosanoid output by human airway epithelial cells in vitro. We also determined the spectrum of eicosanoids affected and the mechanism for corticosteroid action.

METHODS

Cultured BEAS-2B airway epithelial cells (a transformed cell line) were exposed to corticosteroids (1 nmol/L to 1 micromol/L) for 2 to 48 hours and then assayed for basal- and bradykinin (BK)-stimulated eicosanoid output. The eicosanoid profile was identified by HPLC in tritiated arachidonic acid prelabelled cells, and PGE2, the major eicosanoid product, was quantitated by RIA. The effect of corticosteroids on the immunoreactivity of key proteins involved in eicosanoid metabolism (ie, cyclooxygenase [COX], phospholipase A2 [PLA2], and Clara cell protein, a PLA2 inhibitor) was determined by Western blotting.

RESULTS

Eicosanoid output was largely confined to prostaglandins with values of 5 +/- 2 and 82 +/- 35 ng PGE2/10(6) cells for basal- and BK stimulation, respectively (n = 8). All 3 corticosteroids inhibited basal- and BK-induced PGE2 output in a dose- and time-dependent manner. Fluticasone and budesonide completely eliminated PGE2 output in nanomolar concentrations in contrast to triamcinolone, which required micromolar concentration. The rank order of potency was: fluticasone = budesonide > triamcinolone. The time course of action for PGE2 inhibition also differed, with budesonide acting more slowly than the other 2 corticosteroids (P = .04). All 3 corticosteroids markedly reduced COX2 with little effect on COX1, cPLA2 (Type IV), or iPLA2 (Type VI) immunoreactivity or their relative distribution in cytosol versus membrane fractions. Clara cell protein immunoreactivity was undetectable in control and corticosteroid-treated cell lysates.

CONCLUSION

These results show that in a human airway epithelial cell line, the 3 inhaled corticosteroids commonly used to treat asthma differ in onsets of action as inhibitors of prostaglandin synthesis and vary considerably in potency. All 3 corticosteroids act mechanistically in similar fashion by inhibiting COX2 synthesis.

[The experimental investigation of epithelial healing in rabbit central corneal alkali wounds]

PURPOSE

To observe the morphologic changes of epithelium in the alkali wounds at the central corneal of rabbits.

METHODS

38 rabbits weighing 2.5 kg were used. A alkali wound of the corneas was performed in the right eye of 38 New Zealand white rabbits with round filter paper, 8 mm in diameter, which were soaked in 0.5 mol/L NaOH for 5 seconds and then were placed centrally on the cornea for 60 seconds. The corneal burns were examined and photographed after the staining of 2% fluoresent staining with a slit lamp every day. The excised corneas were examined in the light microscope, electron microscope.

RESULTS

The epithelial cells had rapidly disappeared in the burned area. The epithelial cells regrowth started at 8 hours following the burn, and 1-2 layers epithelial cells covered the burned area by 24 hours. The epithelial defects occured again on the 4th day. The desmosome and microvilli of the regenerating epithelium had a reduced number. There was no basement membrane between the regenerating epithelium and the strom. There were increased intercellular spaces between the regenerating epithalial cells.

CONCLUSION

The epithelial healing were achieved through the division and migration of epithelial cells at the margin of the wound in rabbit central corneal alkali wound. The decrease of the junctions and the increase of intercellular spaces between the regenerating epithalial cells may be responsible for the second epithelial defects.

Cofactors for human immunodeficiency virus entry into primary macrophages

Macrophages are permissive for macrophage-tropic (M-tropic) human immunodeficiency virus type 1 (HIV-1) isolates that use CCR5 for entry but are resistant to CXCR-4-dependent T cell-tropic prototype strains. M-tropic variants are critical for HIV-1 transmission, and persons who are homozygous for an inactivating mutation of CCR5 are resistant to HIV-1 in vivo. In vitro, their macrophages and lymphocytes are resistant to M-tropic strains that depend on CCR5. It is shown that CCR5-deficient macrophages are permissive for a dual-tropic isolate, 89.6, that uses CCR5, CXCR-4, and other cofactors. Entry by 89.6 into CCR5-deficient macrophages was blocked by the CXCR-4 ligand SDF and by an anti-CXCR-4 antibody. Immunoflorescence staining and reverse transcription PCR confirmed macrophage CXCR-4 expression. Thus, CXCR-4 on macrophages mediates entry of certain dual-tropic but not T cell-tropic isolates. Therefore, HIV-1 strains differ in how they utilize chemokine receptors as cofactors for entry, and the ability of a chemokine receptor to facilitate entry depends on the cell in which it is expressed.

[Expression and significance of Fas/APO-1 and Bcl-2 protein in human lung cancer.]

BACKGROUND

To investigate the role of Fas/APO-1 and Bcl-2 in oncogenesis and progression of lung cancer.

METHODS

The expression of Fas/APO-1 and Bcl-2 protein were detected in 65 lung cancer tissues and 46 normal lung tissues by immunohistochemistry.

RESULTS

The positive rate of Fas/APO-1 protein expression in lung cancer tissues was 56. 92 % , which was significantly lower than that in normal lung tissues (82. 61 %) ( P < 0. 01) . The positive rate of Bcl-2 protein expression was 46. 15 %. It was significantly higher than that in normal lung tissues (6. 52 %) ( P < 0. 01) .

CONCLUSIONS

Both Fas/APO-1 and Bcl-2 may play an role in the oncogenesis and progression of lung cancer.

Generation of enhancer trap lines in Arabidopsis and characterization of expression patterns in the inflorescence

Eleven thousand, three hundred and seventy enhancer/promoter trap lines in Arabidopsis were generated via T-DNA transformation utilizing the binary vector pD991 that contains a minimal promoter fused to the uidA reporter gene. Overall 31% of the lines generated exhibit a staining pattern in the inflorescence. Flanking DNA has been cloned from 15 lines exhibiting inflorescence staining patterns by either thermal asymmetric interlaced PCR (TAIL-PCR), inverse PCR (IPCR), or partial library construction. Seeds from these lines are available from the ABRC and NASC Arabidopsis stock centers and DNA pools are available from the ABRC.

[Separation and detection of tryptophan metabolites in biological samples]

A reversed phase HPLC method for separation and determination of the major tryptophan (TRP) metabolites in both pyrrolas pathway and TRP hydroxylase pathway, including TRP, kynurenine(KN), 3-hydroxykynurenine(3-HKN), kynurenic acid(KA), xanthurenic acid(XA), 5-hydroxytryptophan(5-HTP), 5-hydroxytryptamin(5-HT) and 5-hydroxyindoleacetic acid(5-HIAA), has been developed by sequential optimization of mobile phase based on acetate buffer and methanol. Trichloroacetic acid(TCA) was used as ion-pairing reagent to increase the retention of 3-HKN. The effects of pH and concentrations of TCA on separation were studied. Good separation can be achieved at pH 4.0-5.0 of mobile phase in less than 25 min. When TCA was not used, 3-HKN was hard to be detected in biological samples. The maximum retention of 3-HKN was obtained at pH 4.0 with mobile phase containing 50 mmol/L TCA. Combination of electrochemical (ED) and ultraviolet (UV) detection was used in which ED was responsible for detection of 3-HKN, 5-HTP, 5-HT and 5-HIAA and UV for the others. The influences of potential of ED and wavelength of UV on detection were studied. The optimization of conditions for separation and detection in different biological samples was also discussed.

Development of TGF-beta resistance during malignant progression

Transforming growth factor-beta (TGF-beta) is the prototypical multifunctional cytokine, participating in the regulation of vital cellular activities such as proliferation and differentiation as well as a number of basic physiological functions. The effects of TGF-beta are critically dependent on the expression and distribution of a family of TGF-beta receptors, the TGF-beta types I, II, and III. It is now known that a wide variety of human pathology can be caused by aberrant expression and function of these receptors. The coding sequence of the type II receptor (RII) appears to render it uniquely susceptible to DNA replication errors in the course of normal cell division. By virtue of its key role in the regulation of cell proliferation, TGF-beta RII should be considered as a tumor suppressor gene. High levels of mutation in the TGF-beta RII gene have been observed in a wide range of primarily epithelial malignancies, including colon and gastric cancer. It appears likely that mutation of the TGF-beta RII gene may be a very critical step in the pathway of carcinogenesis.

[Cerebral hemodynamic impairment and therapeutic effect of external counterpulsation on elderly patients with brain infarction]

Hemodynamic parameters of middle cerebral artery(MCA) were measured with Transcranial Doppler (TCD) in 31 elderly patients with brain infarction during convalescence and 28 healthy elderly controls. Twenty-two elderly patients with brain infarction and cerebral hemodynamic impaired were treated by External Counterpulsation(ECP). The results showed that the Vp and Vm of MCA in patients were significantly lower than that in the healthy controls(P < 0.001), the DVp, DVm and asymmetry of MCA in patients were greater than that in the healthy elderly(P < 0.001, P < 0.005). The Vp and Vm of MCA in patients after ECP were significantly higher than before(P < 0.001). The DVp, DVm and asymmetry of MCA in patients after ECP were significantly lower than before(P < 0.001, P < 0.005). The hemodynamic therapeutic effect is 81.8%.

[An investigation on chromosome aberration of SO-Rb50 cloned cell strains]

PURPOSE

To compare the differences of chromosome aberration among 3 cloning cells (MC2, MC3 and MC4) of SO-Rb50 cell line.

METHOD

G-banding and karyotype analysis were performed on the 11th passage cells of MC2, MC3 and MC4 cell strains.

RESULTS

Both numerical abnormal and structural aberrations of chromosomes could be observed in these 3 cloned cell strains. Diploid cells had the preponderance over the aneuploid cells. However, some cells showed pseudiploid karyotypes. Several kinds of structural chromosome aberrations were observed. The chromosome aberrations in the same passage of different cell strains were different. Aberration of chromosome 13 was rare and the aberration feature were different in 3 cloned cell strains. Five marker chromosomes were identified. M1, t(1;1) qterp35::q24-ter could be found in all cell strains. Other markers were seen in different cell strains respectively. In our experiment, two marker chromosome in chromosome 2, M4 and M5, were found in SO-Rb50 cell line for the first time.

CONCLUSION

Chromosome aberrations were different with different cloned cell strains. Combined with formerly study in SO-Rb50 cell line, we found the chromosome aberration had dynamic changes during the long-term culture in vitro. We suggest that aberration of chromosome 13 is not the only cause of Rb; aberration of chromosome 1, a common event in some neoplasias as well as in SO-Rb50, plays a meaningful role in the immortalization of this cell line; other aberrations observed in our experiment could be considered as evidences of genomic instability of the cell strains and presumably enhance the growth potential of the cells in which they develop.

[Morphological observation of the endogenous endophthalmitis of cryptococcus neoformans]

PURPOSE

To observe the pathologic change of the endogenous endophthalmitis of cryptococcus neoformans.

METHODS

Light and electron microscope were used.

RESULT

The choroid was focally tumor-like by an inflammatory cells infiltrate, which consisted of multinucleated gicant, epithelioid cells and lymphocytes. Special stains (Grocott's methnamine silver, PAS, alcian blue) and electron microscope disclosed the budding form of cryptococcus neoformans.

CONCLUSION

The morphologic examinations are only an effectivel method of diagrosing the endogenous endophthalmitis of cryptococcus neoformans.

[Studies on the chemical constituents of Smilax glabra]

Smilax glabra is a well-known traditional Chinese medicine which has been used clinically to prevent leptospirosis, to treat syphilis, and acute bacterial dysentery, etc. Its extracts showed anti-tumor and anti-atherosclerosis activity. A new isoflavone, 7,6'-dihydroxy 3'-methoxy isoflavone (1), along with two known compounds taxifolin (2) and astilbin (3), have been isolated from the roots of Smilax glabra. The structures were elucidated by spectroscopic methods including 2DNMR techniques.

An orphan seven-transmembrane domain receptor expressed widely in the brain functions as a coreceptor for human immunodeficiency virus type 1 and simian immunodeficiency virus

Both CD4 and an appropriate coreceptor are necessary for infection of cells by human immunodeficiency virus type 1 (HIV-1) and most strains of HIV-2. The chemokine receptors CCR5 and CXCR4 are the major HIV-1 coreceptors, although some virus strains can also utilize alternative coreceptors such as CCR3 to infect cells. In contrast, most if not all simian immunodeficiency virus (SIV) strains use CCR5 as a coreceptor, and many SIV strains can use CCR5 independently of CD4. In addition, several orphan seven-transmembrane receptors which can serve as HIV-1 and SIV coreceptors have been identified. Here we report that APJ, an orphan seven-transmembrane domain receptor with homology to the angiotensin receptor family, functions as a coreceptor for a number of HIV-1 and SIV strains. APJ was expressed widely in the human brain and in NT2N neurons. APJ transcripts were also detected by reverse transcription-PCR in the CD4-positive T-cell line C8166, but not in peripheral blood leukocytes, microglia, phytohemagglutinin (PHA)- or PHA/interleukin-2-stimulated peripheral blood mononuclear cells, monocytes, or monocyte-derived macrophages. The widespread distribution of APJ in the central nervous system coupled with its use as a coreceptor by some HIV-1 strains indicates that it may play a role in neuropathogenesis.

Influence of the CCR2-V64I polymorphism on human immunodeficiency virus type 1 coreceptor activity and on chemokine receptor function of CCR2b, CCR3, CCR5, and CXCR4

The chemokine receptors CCR5 and CXCR4 are used by human immunodeficiency virus type 1 (HIV-1) in conjunction with CD4 to infect cells. In addition, some virus strains can use alternative chemokine receptors, including CCR2b and CCR3, for infection. A polymorphism in CCR2 (CCR2-V64I) is associated with a 2- to 4-year delay in the progression to AIDS. To investigate the mechanism of this protective effect, we studied the expression of CCR2b and CCR2b-V64I, their chemokine and HIV-1 coreceptor activities, and their effects on the expression and receptor activities of the major HIV-1 coreceptors. CCR2b and CCR2b-V64I were expressed at similar levels, and neither molecule affected the expression or coreceptor activity of CCR3, CCR5, or CXCR4 in cotransfected cell lines. Peripheral blood mononuclear cells (PBMCs) from CCR2-V64I heterozygotes had normal levels of CCR2b and CCR5 but slightly reduced levels of CXCR4. CCR2b and CCR2b-V64I functioned equally well as HIV-1 coreceptors, and CCR2-V64I PBMCs were permissive for HIV-1 infection regardless of viral tropism. The MCP-1-induced calcium mobilization mediated by CCR2b signaling was unaffected by the polymorphism, but MCP-1 signaling mediated by either CCR2b- or CCR2-V64I-encoded receptors resulted in heterologous desensitization (i.e., limiting the signal response of other receptors) of both CCR5 and CXCR4. The heterologous desensitization of CCR5 and CXCR4 signaling by both CCR2 allele receptor types provides a mechanistic link that might help explain the in vivo effects of CCR2 gene variants on progression to AIDS as well as the reported antiviral activity of natural CCR2 ligands.

An intragenic suppressor of the Arabidopsis floral organ identity mutant apetala3-1 functions by suppressing defects in splicing

The Arabidopsis floral organ identity gene APETALA3 (AP3) specifies the identity of petals and stamens in the flower. In flowers mutant for the temperature-sensitive ap3-1 allele, the petals and stamens are partially converted to sepals and carpels, respectively. ap3-1 contains a single nucleotide change in the AP3 gene that alters both an amino acid in the AP3 protein and the 5' splice consensus site for intron 5. Surprisingly, the Ap3-1 mutant phenotype is not due to the missense mutation but instead is due to defects in splicing; specifically, exon 5 is frequently skipped by the splicing machinery at the restrictive temperature. In a screen for suppressors of ap3-1, we isolated an intragenic suppressor, ap3-11, that functions to suppress the splicing defects of ap3-1. Using a reverse transcriptase-polymerase chain reaction assay, we demonstrate that the percentage of full-length exon 5-containing AP3 RNAs correlates with the phenotype of the flowers in both ap3-1 and ap3-11. Rather surprisingly, the ap3-11 suppressor mutation is located in intron 4. One model explaining the function of ap3-11 is that the ap3-11 suppressor creates a novel branch point sequence that causes exon 5 to be more frequently recognized by the splicing machinery. The identification of such a suppressor strongly suggests that exon-scanning models of intron-exon recognition are operative in plants.

[The establishment, freezing-state preservation and resuscitation of retinoblastoma SO-Rb70 cell line]

PURPOSE

To establish a new cell line of human retinoblastoma (Rb), frozen and resuscitated to provide a Rb cell reservoir for clinical and experimental research.

METHODS

The screening cells were washed and blown directly without centrifugation and then inoculated. Based on the cell-frozen principle, the Rb cell line was collected and established, then frozen in liquid nitrogen and resuscitated.

RESULTS

SO-Rb70 cell line was established successfully. 8 groups of cells were frozen. The resuscitation experiment was carried out for 6 times, 4 times being successful.

CONCLUSION

The preserved human Rb cells in liquid nitrogen grew normally after resuscitation with the maintenance of previous bioactivities and characteristics. This research helped to provide abundant material for further study of Rb.

Determinants of entry cofactor utilization and tropism in a dualtropic human immunodeficiency virus type 1 primary isolate

Human immunodeficiency virus type 1 strain 89.6 is a dualtropic isolate that replicates in macrophages and transformed T cells, and its envelope mediates CD4-dependent fusion and entry with CCR5, CXCR-4, and CCR3. To map determinants of cofactor utilization by 89.6 and determine the relationship between cofactor use and tropism, we analyzed recombinants generated between 89.6 and T-cell-tropic (HXB) or macrophage-tropic (JRFL) strains. These chimeras showed that regions of 89.6 env outside V3 through V5 determine CXCR-4 utilization and T-cell line tropism as well as CCR5 utilization and macrophage tropism. However, the 89.6 env V3 domain also conferred on HXB the ability to use CCR5 for fusion and entry but not the ability to establish productive macrophage infection. CCR3 use was conferred on HXB by 89.6 env V3 or V3 through V5 sequences. While replacement of the 89.6 V3 through V5 region with HXB sequences abrogated CCR3 utilization, replacement of V3 or V4 through V5 separately did not. Thus, CCR3 use is determined by sequences within V3 through V5 and most likely can be conferred by either the V3 or the V4 through V5 domains. These results indicate that cofactor utilization and tropism in this dualtropic isolate are determined by complex interactions among multiple env segments, that distinct regions of the Env glycoprotein may be important for utilization of different chemokine receptors, and that determinants in addition to cofactor usage participate in postentry stages in the virus replication cycle that contribute to target cell tropism.

[Assessment of six drug sensitivities in established cell lines of SO-Rb50 and SO-Rb70]

OBJECTIVE

With retinoblastoma (Rb) cell lines cultured in vitro to screen chemotherapeutic drugs that are effective on Rb.

METHOD

Sensitivity experiments were performed with the 3, -4, 5 Dimethyliazol-2, 5 diphenyl tetrazolium bromide (MTT) assay for the drugs: dactinomycin (DACT), vincristine (VCR), VM-26, daunorubicin (DNR), DDP, bleomycin (BLMA5) against the tumor cell lines of SO-Rb50 and SO-Rb70.

RESULTS

The IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb50 were respectively 0.0004, 0.0016, 0.0389, 0.047, 0.29, 0.44, and those at 72 hours were 0.00025, 0.00081, 0.0151, 0.0192, 0.097, 0.11. And the IC(50) values (microg/ml) in order at 48 hours of the above pharmaceuticals against SO-Rb70 were respectively 0.00065, 0.00149, 0.0282, 0.043, 0.37, 0.215, and those at 72 hours were 0.00042, 0.00082, 0.0146, 0.0176, 0.035, 0.084.

CONCLUSION

The tumor cell lines of SO-Rb50 and SO-Rb70 were sensitive to the above six pharmaceuticals. By their IC(50) values, the sensitivity order to the drugs, from higher to lower, was DACT, VCR, VM-26, DNR, DDP, BLMA5.

[A case-control study on diet and gastric cancer]

OBJECTIVE

To study the relationship between consumption of fish sauce, diet, living-habit and risk of gastric cancer.

METHODS

A population-based 1:2 matched case-control study was conducted in Changle and Fuqing Cities of Fujian Province during May 1994 to July 1995. Totally, 272 matched pairs were investigated.

RESULTS

Risk state single-factor analysis indicated that there were significant associations between occurrence of gastric cancer and over consumption of fish sauce (OR = 2.57), pickled vegetables (OR = 1.41) and sea food (OR = 1.57), low consumption of fresh vegetables (OR = 1.95), citrus fruits (OR = 1.41), other fruits (OR = 1.31) and green tea (OR = 1.72), exposure to moldy cereals (OR = 2.32), taking meals at irregular times (OR = 5.47) and familial history of malignancy (OR = 3.27). No associations between risk of gastric cancer and smoking, alcohol drinking, amount of salft consumption, use of refrigerator were found. Analysis of risk state conditional logistic regression showed that fish sauce, pickled sea food, irregularly taking meals and familial history of malignancy were included in a set of risk factors for gastric cancer, with a summary attributable risk percentage of 75.49%.

CONCLUSION

Over consumption of fish sauce, pickled food, moldy cereals, irregularly taking meals and familial history of malignancy may be the local risk factors for high occurrence of gastric cancer, and fresh vegetables and fruits, green tea may have protective effects on it.

A novel ets-related transcription factor, ERT/ESX/ESE-1, regulates expression of the transforming growth factor-beta type II receptor

A 2.5-kilobase cDNA clone that encodes a 371-amino acid novel transcription factor was isolated from a human placenta cDNA library using a yeast one-hybrid system. The novel ets-related transcription factor (ERT) showed a homology with the ETS DNA-binding domain. Using constructs of the transforming growth factor-beta (TGF-beta) type II receptor (RII) promoter linked to the luciferase gene, we have demonstrated that ERT activates transcription of the TGF-beta RII gene through the 5'-TTTCCTGTTTCC-3' response element spanning nucleotides +13 to +24 and multiple additional ETS binding sites between -1816 and -82 of the TGF-beta RII promoter. A specific interaction between ERT and the ETS binding sites was also demonstrated using an electrophoretic mobility shift assay. Deletion mapping of ERT protein suggests that the transactivation domain resides in the amino terminus while the DNA-binding domain is localized to the carboxyl-terminal region. Our results suggest that ERT might be a major transcription factor involved in the transcriptional regulation of the TGF-beta RII gene.

CXCR-4 is expressed by primary macrophages and supports CCR5-independent infection by dual-tropic but not T-tropic isolates of human immunodeficiency virus type 1

Primary macrophages are infected by macrophage (M)-tropic but not T-cell line (T)-tropic human immunodeficiency virus type 1 (HIV-1) strains, and CCR5 and CXCR-4 are the principal cofactors utilized for CD4-mediated entry by M-tropic and T-tropic isolates, respectively. Macrophages from individuals homozygous for an inactivating mutation of CCR5 are resistant to prototype M-tropic strains that depend on CCR5 but are permissive for a dual-tropic isolate, 89.6, that can use both CCR5 and CXCR-4, as well as CCR2b, CCR3, and CCR8. Here we show that 89.6 entry into CCR5-deficient macrophages is blocked by an anti-CXCR-4 antibody and by the CXCR-4-specific chemokine SDF but not by the ligands to CCR2b or CCR3. Reverse transcription-PCR demonstrated expression of CXCR-4 but not CCR3 or CCR8 in macrophages, while CCR2b was variable. Macrophage surface expression of CXCR-4 was confirmed by immunofluorescence staining and flow cytometry. Thus, CXCR-4 is expressed by primary macrophages and functions as a cofactor for entry by dual-tropic but not T-tropic HIV-1 isolates, and macrophage resistance to T-tropic strains does not result from a lack of the T-tropic entry cofactor CXCR-4. Since CXCR-4 on macrophages can be used by some but not other isolates, these results indicate that HIV-1 strains differ in how they utilize chemokine receptors as cofactors for entry and that the ability of a chemokine receptor to mediate HIV-1 entry differs, depending on the cell type in which it is expressed.

Utilization of chemokine receptors, orphan receptors, and herpesvirus-encoded receptors by diverse human and simian immunodeficiency viruses

Human immunodeficiency virus type 1 (HIV-1) requires both CD4 and a coreceptor to infect cells. Macrophage-tropic (M-tropic) HIV-1 strains utilize the chemokine receptor CCR5 in conjunction with CD4 to infect cells, while T-cell-tropic (T-tropic) strains generally utilize CXCR4 as a coreceptor. Some viruses can use both CCR5 and CXCR4 for virus entry (i.e., are dual-tropic), while other chemokine receptors can be used by a subset of virus strains. Due to the genetic diversity of HIV-1, HIV-2, and simian immunodeficiency virus (SIV) and the potential for chemokine receptors other than CCR5 or CXCR4 to influence viral pathogenesis, we tested a panel of 28 HIV-1, HIV-2, and SIV envelope (Env) proteins for the ability to utilize chemokine receptors, orphan receptors, and herpesvirus-encoded chemokine receptor homologs by membrane fusion and virus infection assays. While all Env proteins used either CCR5 or CXCR4 or both, several also used CCR3. Use of CCR3 was strongly dependent on its surface expression levels, with a larger number of viral Env proteins being able to utilize this coreceptor at the higher levels of surface expression. ChemR1, an orphan receptor recently shown to bind the CC chemokine I309 (and therefore renamed CCR8), was expressed in monocyte and lymphocyte cell populations and functioned as a coreceptor for diverse HIV-1, HIV-2, and SIV Env proteins. Use of ChemR1/CCR8 by SIV strains was dependent in part on V3 loop sequences. The orphan receptor V28 supported Env-mediated cell-cell fusion by four T- or dual-tropic HIV-1 and HIV-2 strains. Three additional orphan receptors failed to function for any of the 28 Env proteins tested. Likewise, five of six seven-transmembrane-domain receptors encoded by herpesviruses did not support Env-mediated membrane fusion. However, the chemokine receptor US28, encoded by cytomegalovirus, did support inefficient infection by two HIV-1 strains. These findings indicate that additional chemokine receptors can function as HIV and SIV coreceptors and that surface expression levels can strongly influence coreceptor use.

[Comparison of the Chinese LJ strain structural gene with HM175, MBB, LA strains and the expression of hepatitis A virus antigen by LJ/HM175 recombinant vaccinia virus]

The nucleotide and amino acid sequences of a Chinese hepatitis A virus Long-Jia (LJ) strain were compared with that of HM175, MBB and LA strains in structural genes (nt 630-3049). The most extensive nucleotide homology was identified between LJ and MBB strains. The identity rates of nucleotide were 95.4%, 96.7% and 91.4%, respectively. Variation rates of amino acid were 0.91%, 0.91% and 2.98%, respectively. A total of 23 amino acid differences located in whole capsid region between LJ and LA strain, especially in VP1. Only 7 amino acid differences located in VP2 and VP3 between LJ and HM175/MBB strain. Restriction enzyme sites increased 10, 13 and 30 sites in 56 restriction enzymes tested, and decreases 15, 1 and 27 sites, respectively. BstE II (nt 2810) and Pvu I (nt 2013) were the peculiar sites of LJ strain. Hind III, Pst I and Sac I sites were identical among the four strains. After structural gene (nt 745-2993) of HM175 strain was replaced by LJ strain, the complete hepatitis A virus cDNA open reading frame was inserted into pJSA1175 (vaccinia virus expression vector) downstream of promoter 7.5 k. Hepatitis A virus antigen expressed was 1:16 in titer by sandwich ELISA. Band-patterns of anti-VP0, anti-VP1 and anti-VP1, 2, 3, were as same as that of HM175 strain and natural hepatitis A virus antigen by Western blot analysis.

Abortive infection in HeLaCD4 cells by a primary HIV type 1 isolate: implications for differential host cell tropism

The emergence of T cell-tropic, syncytium-inducing (T-tropic/SI) HIV-1 variants from the background of macrophage-tropic, non-syncytium-inducing (M-tropic/NSI) strains is associated with disease progression in infected individuals. HIV89.6 is a primary isolate with a transitional phenotype: like M-tropic strains it replicates in primary macrophages and lymphocytes but not in most transformed cells, yet it is also syncytium inducing. We have shown that HIV89.6 can utilize both the M-tropic and T-tropic cofactors CCR-5 and CXCR-4, respectively, in conjunction with CD4 for fusion and entry into otherwise nonpermissive nonhuman cells. To better understand the nature of restricted HIV89.6 infection of transformed cells, we analyzed its interaction with CD4-expressing transformed human HeLaCD4-LTR/beta-Gal cells, which contain the beta-galactosidase gene linked to the HIV-1 LTR. Here we show that HIV89.6 enters these cells and undergoes reverse transcription and integration. Furthermore, HIV89.6 induces LTR-driven beta-galactosidase expression, indicating Tat-dependent trans-activation, in a similar number of cells as the permissive T-tropic/SI isolate HIV(HXB). Acute infection with HIV89.6, however, produces markedly lower levels of p24 antigen and infectious virus per trans-activation-positive cell than HIV(HXB). In contrast, transfection results in high levels of expression for both viruses but HIV89.6 still fails to establish spreading infection. HIV89.6 is also blocked after entry in two other nonpermissive cell lines, SUP-T1 and U937. HIV89.6 arrest in HeLaCD4-LTR/beta-Gal cells at a stage subsequent to entry, reverse transcription, integration, and Tat expression is a novel level at which HIV-1 strain- and cell-specific restrictions define host cell tropism. These studies emphasize that complex patterns of tropism are determined by the interplay of permissive or restricted virus-cell interactions at multiple steps in the replication cycle.

[Clinical and histological findings of retrocorneal membrane after keratoplasty]

PURPOSE

To observe the clinicopathologic changes of retrocorneal membrane after keratoplasty.

METHODS

Light microscope and histochemical technique were used.

RESULTS

The clinicopathologic review of 108 unsuccessful keratoplasties revealed the presence of 45 retrocorneal membrane, which seems to depend on the wound abnormality, rejection of corneal transplantion, epithelium in growth, hyphema, and iris synechias.

CONCLUSION

The retrocorneal membrane derives from the host corneal stromal keratocytes and the metaplasia of corneal endothelial cells and monocytes.

[Liver-protective activity of Aralia taibaiensis Z.Z. Wang et H.C. Zheng]

Compared with oleanolic acid and sodium chloride physiological solution, the water decoction of and the total saponin in root and cortex of Aralia taibaiensis were testified to have significant protective activity in experimental acute liver injury in mice induced by CCl4.

Autoimmunity to heat shock protein 60 and antigen-specific production of interleukin-10

The immunopathologic sequelae of chlamydial infection are correlated with immune responses to the Chlamydia trachomatis heat shock protein 60 (hsp60). One pathogenic mechanism that may explain this association is the induction of autoimmune responses to self hsp60, since these two proteins share a high degree of amino acid sequence identity. To investigate the conditions under which autoimmune responses can be generated against self hsp60, groups of CBA mice were immunized with recombinant mouse hsp60, recombinant chlamydial hsp60, or both proteins. The data show that autoimmune responses characterized by strong T-cell proliferation and high titers of antibody to self hsp60 are induced only by concurrent immunization with mouse and chlamydial hsp60. Immunization with mouse hsp60 alone induced lymphocytes that secreted high levels of interleukin-10 (IL-10) but did not proliferate in response to in vitro stimulation with mouse hsp60; coimmunization with mouse and chlamydial hsp60s induced lymphocytes that proliferated strongly in response to mouse hsp60, secreted 6-fold less IL-10, and exhibited a 12-fold increase in the ratio of gamma interferon/IL-10 production. Switches in cytokine production patterns may mediate the pathogenesis of hsp60-associated diseases such as C. trachomatis immunopathology.

Role of CCR5 in infection of primary macrophages and lymphocytes by macrophage-tropic strains of human immunodeficiency virus: resistance to patient-derived and prototype isolates resulting from the delta ccr5 mutation

The alpha-chemokine receptor fusin (CXCR-4) and beta-chemokine receptor CCR5 serve as entry cofactors for T-cell (T)-tropic and macrophage (M)-tropic human immunodeficiency virus type 1 (HIV-1) strains, respectively, when expressed with CD4 in otherwise nonpermissive cells. Some M-tropic and dual-tropic strains can also utilize other beta-chemokine receptors, such as CCR2b and CCR3. A mutation of CCR5 (delta ccr5) was recently found to be common in certain populations and appears to confer protection against HIV-1 in vivo. Here, we show that this mutation results in a protein that is expressed intracellularly but not on the cell surface. Primary CD4 T cells from delta ccr5 homozygous individuals were highly resistant to infection with prototype M-tropic HIV-1 strains, including an isolate (YU-2) that uses CCR5 and CCR3, but were permissive for both a T-tropic strain (3B) and a dual-tropic variant (89.6) that uses CXCR-4, CCR5, CCR3, or CCR2b. These cells were also resistant to M-tropic patient isolates but were readily infected by T-tropic patient isolates. Primary macrophages from delta ccr5 homozygous individuals were also resistant to infection with M-tropic strains, including YU-2, but the dual-tropic strain 89.6 was able to replicate in them even though macrophages are highly resistant to CXCR-4-dependent T-tropic isolates. These data show that CCR5 is the essential cofactor for infection of both primary macrophages and T lymphocytes by most M-tropic strains of HIV-1. They also suggest that CCR3 does not function for HIV-1 entry in primary lymphocytes or macrophages, but that a molecule(s) other than CCR5 can support entry into macrophages by certain virus isolates. These studies further define the cellular basis for the resistance to HIV-1 infection of individuals lacking functional CCR5.

[Resources survey of medicinal species from genus Aralia]

This paper deals with the distribution area, growing environment and medicinal parts of 19 species and 1 variety, including 2 new species of genus Aralia. An index for identification of these medicinal species is presented.

[Observation of the invasion of retinoblastoma cells to ocular tissues in vitro]

PURPOSE

To study the invasion of retinoblastoma cells to ocular tissues.

METHODS

The SO-Rb50 cells of retinoblastoma and various ocular tissue cells were co-cultured. The morphological change of the SO-Rb50 cells adherent to ocular tissue cells was observed.

RESULTS

SO-Rb50 cells can adhere to the various ocular tissues. The adherent ability of SO-Rb50 cell to different ocular tissue cells was different. Tumor cells could be adhesive to keratocyte, scleral fibrocyte, the fibrocyte and the melanocyte of iris and choroid, the epithelial cells of lens, and the astrocyte of optic nerve and grow, but can not be adhesive to the corneal epithelial cell and retinal pigment epithelial cell.

CONCLUSIONS

We consider that the interactions of tumor cells with host cells, as with extracellular matrix, also play an important role in the selective growth of organ and tissue of tumor cell metastasis. Retinoblastoma cells can not adhere to retinal pigment epithelial cell, which may serve as a barrier to obstruct the invasion of tumor cell to the choroid. Being adherent to the glial cells of optic nerve, tumor cells grow in flat and the shape of tumor cell changes, which may be the cause of tumor cell migrate rapidly and grow in the brain while the optic nerve was invaded by tumor cells.

[Observation of the invasion of retinoblastoma cells to the corneal epithelial cells and keratocytes in culture]

OBJECTIVE

To study the invasive ability of retinoblastoma cells into the corneal epithelial cells and keratocytes in culture.

METHODS

SO-Rb50 cells of retinoblastoma, corneal epithelial cells and keratocytes were co-cultured. The morphological changes of SO-Rb50 cells adherent to the corneal epithelial cells and keratocytes were observed. The distribution of proteoglycans in the SO-Rb50 cells, corneal cells and keratocytes was analyzed by histochemical method and electron microscopy.

RESULTS

SO-Rb50 cells could adhere to the keratocytes, but did not adhere to the corneal epithelial cells. There are common hyaluronidase-resistant and chondroitinase-resistant proteoglycans on the surface of SO-Rb50 cells and corneal epithelial cells. Chondroitin is present on the surface of keratocytes.

CONCLUSION

It is considered that the cell surface proteoglycans may play an important role in mediating SO-Rb50 tumor cell adhesion and non-adhesion to normal cells.

Regions in beta-chemokine receptors CCR5 and CCR2b that determine HIV-1 cofactor specificity

Macrophage-tropic (M-tropic) HIV-1 strains use the beta-chemokine receptor CCR5, but not CCR2b, as a cofactor for membrane fusion and infection, while the dual-tropic strain 89.6 uses both. CCR5/2b chimeras and mutants were used to map regions of CCR5 important for cofactor function and specificity. M-tropic strains required either the amino-terminal domain or the first extracellular loop of CCR5. A CCR2b chimera containing the first 20 N-terminal residues of CCR5 supported M-tropic envelope protein fusion. Amino-terminal truncations of CCR5/CCR2b chimeras indicated that residues 2-5 are important for M-tropic viruses, while 89.6 is dependent on residues 6-9. The identification of multiple functionally important regions in CCR5, coupled with differences in how CCR5 is used by M- and dual-tropic viruses, suggests that interactions between HIV-1 and entry cofactors are conformationally complex.

Genetic evidence that induction of root Fe(III) chelate reductase activity is necessary for iron uptake under iron deficiency

Reduction of Fe(III) to Fe(II) by Fe(III) chelate reductase is thought to be an obligatory step in iron uptake as well as the primary factor in making iron available for absorption by all plants except grasses. Fe(III) chelate reductase has also been suggested to play a more general role in the regulation of cation absorption. In order to experimentally address the importance of Fe(III) chelate reductase activity in the mineral nutrition of plants, three Arabidopsis thaliana mutans (frd1-1, frd1-2 and frd1-3), that do not show induction of Fe(III) chelate reductase activity under iron-deficient growth conditions, have been isolated and characterized. These mutants are still capable of acidifying the rhizosphere under iron-deficiency and accumulate more Zn and Mn in their shoots relative to wild-type plants regardless of iron status. frd1 mutants do not translocate radiolabeled iron to the shoots when roots are presented with a tightly chelated form of Fe(III). These results: (1) confirm that iron must be reduced before it can be transported, (2) show that Fe(III) reduction can be uncoupled from proton release, the other major iron-deficiency response, and (3) demonstrate that Fe(III) chelate reductase activity per se is not necessarily responsible for accumulation of cations previously observed in pea and tomato mutants with constitutively high levels of Fe(III) chelate reductase activity.

The IE2 regulatory protein of human cytomegalovirus induces expression of the human transforming growth factor beta1 gene through an Egr-1 binding site

Increases in transforming growth factor beta1 (TGF-beta1) mRNA and biological activity in the early phase of human cytomegalovirus (CMV) infection in fibroblasts are paralleled by increased TGF-beta1-chloramphenicol acetyltransferase (CAT) reporter gene activity. To determine how CMV infection transactivates the TGF-beta1 promoter, we examined the effects of the cotransfected IE2 regulatory protein of human CMV on 5'-deleted TGF-beta1 promoter-CAT reporter genes in transient DNA transfection assays. Two upstream TGF-beta1 promoter regions each containing an Egr-1 consensus site were shown to be important for IE2-induced transactivation in a cell type that displayed greatly reduced nonspecific activity. Furthermore, transfer of an Egr-l site from between positions -125 and -98, but not point mutant versions of this site, to a heterologous promoter also conveyed IE2 responsiveness. Addition of an IE2 expression vector or use of the U373 A45 astrocytoma cell line expressing IE2 also produced synergistic stimulation of GAL4-Egr-l-mediated activation of a target promoter containing GAL4 binding sites. The 80-kDa IE2 protein present in A45 cells proved to selectively bind to glutathione S-transferase (GST)-Egr-1 beads. The results of in vitro protein binding assays also revealed that an intact in vitro-translated IE2 protein bound directly to the GST-Egr-1 fusion protein through the zinc finger domain of the Egr-1 protein and that this binding activity was abolished by deletion of parts of the zinc finger DNA-binding domain. Similarly, the Egr-1 protein was found to associate preferentially with a small region within the C-terminal half of the IE2 protein adjacent to the DNA-binding and dimerization domains that are important for both transactivation and downregulation. We conclude from these observations that IE2 may regulate transcription of the TGF-beta1 gene as well as other potential cellular targets by virtue of its ability to interact with the Egr-1 DNA-binding protein.

Resistance to HIV-1 infection in caucasian individuals bearing mutant alleles of the CCR-5 chemokine receptor gene

HIV-1 and related viruses require co-receptors, in addition to CD4, to infect target cells. The chemokine receptor CCR-5 (ref.1) was recently demonstrated to be a co-receptor for macrophage-tropic (M-tropic) HIV-1 strains, and the orphan receptor LESTR (also called fusin) allows infection by strains adapted for growth in transformed T-cell lines (T-tropic strains). Here we show that a mutant allele of CCR-5 is present at a high frequency in caucasian populations (allele frequency, 0.092), but is absent in black populations from Western and Central Africa and Japanese populations. A 32-base-pair deletion within the coding region results in a frame shift, and generates a non-functional receptor that does not support membrane fusion or infection by macrophage- and dual-tropic HIV-1 strains. In a cohort of HIV-1 infected caucasian subjects, no individual homozygous for the mutation was found, and the frequency of heterozygotes was 35% lower than in the general population. White blood cells from an individual homozygous for the null allele were found to be highly resistant to infection by M-tropic HIV-1 viruses, confirming that CCR-5 is the major co-receptor for primary HIV-1 strains. The lower frequency of heterozygotes in seropositive patients may indicate partial resistance.

A dual-tropic primary HIV-1 isolate that uses fusin and the beta-chemokine receptors CKR-5, CKR-3, and CKR-2b as fusion cofactors

Here, we show that the beta-chemokine receptor CKR-5 serves as a cofactor for M-tropic HIV viruses. Expression of CKR-5 with CD4 enables nonpermissive cells to form syncytia with cells expressing M-tropic, but not T-tropic, HIV-1 env proteins. Expression of CKR-5 and CD4 enables entry of a M-tropic, but not a T-tropic, virus strain. A dual-tropic primary HIV-1 isolate (89.6) utilizes both Fusin and CKR-5 as entry cofactors. Cells expressing the 89.6 env protein form syncytia with QT6 cells expressing CD4 and either Fusin or CKR-5. The beta-chemokine receptors CKR-3 and CKR-2b support HIV-1 89.6 env-mediated syncytia formation but do not support fusion by any of the T-tropic or M-tropic strains tested. Our results suggest that the T-tropic viruses characteristic of disease progression may evolve from purely M-tropic viruses prevalent early in virus infection through changes in the env protein that enable the virus to use multiple entry cofactors.

[Assessment of the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70]

PURPOSE

MTT assay was evaluated on cytoxicity for suspension growing cell lines of SO-Rb50 and SO-Rb70, and the toxicity of TAH (the total alkaloid of peqanum harmala L) on the above cell lines was assessed.

METHODS

The relationships between cell number and optical density, between optical density and exposure time of MTT, and the stability of formazan crystal solution in MDSO were determined. And the toxicity of TAH on the cell lines of SO-Rb50 and SO-Rb70 in vitro with MTT assay was assessed.

RESULTS

There was a direct proportional relationship between the amount of cell number and its optical density; The optical density increased gradully within 12 hours of the MTT incubation time; The stable time of the formazan crystal solved in DMSO was 11 hours. The IC50 values (micrograms/ml) of TAH on SO-Rb50 were 10.66, 4.82 respectively for 48 and 72 hours; and on SO-Rb70 were 6.38, 4.2 respectively for 48 and 72 hours.

CONCLUSION

MTT assay can be used for suspension growing cell lines of SO-Rb50 and SO-Rb70: TAH has obvious toxicity to these two cell lines.