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J Cao

Publications and source records attributed to J Cao.

At least 55 records · Page 3Linked to original sources
PubMed2002

Neutrophils and leucocyte adhesion molecules in sickle cell retinopathy.

AIMS: The expression of the adhesion molecules ICAM-1, VCAM-1, and P-selectin, and the distribution and number of polymorphonuclear leucocytes (PMNs) were investigated in sickle cell retinopathy (SCR) and compared to the normal retina. METHODS: Postmortem ocular tissue was obtained from five subjects (16, 21, 28, 40, and 41 years of age) with sickle haemoglobinopathies and from one control subject. Tissue was cryopreserved, and streptavidin peroxidase immunohistochemistry was performed with antibodies against ICAM-1, VCAM-1, and P-selectin. Immunohistochemical reaction product was scored, and PMN numbers were counted in sections stained with non-specific esterase. RESULTS: Increased ICAM-1, VCAM-1, and P-selectin immunoreactivities were observed in sickle cell subjects compared to the control subject. The highest ICAM and P-selectin immunoreactivity was associated with intraretinal vessels adjacent to the preretinal neovascular formation in subjects with proliferative retinopathy. This was not the case with VCAM-1 immunoreactivity, which was highest in intraretinal vessels adjacent to the sea fan when the sea fan was still "in statu nascendi." Fully formed, "older" sea fans had the highest levels of VCAM-1. The increase in adhesion molecule immunoreactivity was paralleled by an increase in intraretinal PMNs. The number of intraretinal PMNs increased with progression of the disease and the numbers surpassed those in control subjects by threefold. In the sea fan with the greatest VCAM-1 immunoreactivity, there were 20 times more PMNs were observed than in the rest of the retina in the same subject. CONCLUSION: These data suggest that adhesion molecule mediated leucocyte adhesion might play an important part in the vaso-occlusive phase of sickle cell retinopathy and in autoinfarction of sea fan formations.

Adolescent↗
PubMed2002

[Enhancement of immune responses of hepatitis B virus core DNA vaccine by a signal Peptide and a universal helper T lymphocyte epitope].

The human interleukin-2 signal peptide and a potent universal helper T lymphocyte epitope PADRE were spliced to the 5' terminus of hepatitis B viru score HBcAg gene. The modified HBcAg gene was used to construct a DNA vaccine. After the resulted DNA vaccine construct was transfected into COS7 cells, secreted HBcAg was detected in the supernatant by ELISA. BALB/c mice were vaccinated intramuscularly with the modified HBcAg DNA vaccine and the wild-type one. Serum antibodies,T lymphocyte proliferative response and cytotoxic T lymphocyte response of the immunized mice were measured. The results showed that the modified DNA construct induced cellular and humoral immune responses much stronger in vivo than the natural one did, indicating the potential value as a therapeutic vaccine for treatment of chronic hepatitis B.

Animals↗
PubMed2001

[3-cis-3,5-Dimethyl-(1-piperazinyl)alkyl]-bis-(4'-fluorophenyl)amine analogues as novel probes for the dopamine transporter.

In a continuing effort to identify novel probes with which to study the dopamine transporter (DAT), we discovered that the sigma receptor antagonist, rimcazole, binds with moderate affinity (K(i)=224nM) to the DAT. The results from previous SAR studies suggested that substitution of the carbazole ring system of rimcazole with bis-(4'-fluorophenyl)amine might improve binding affinity and selectivity for the DAT. Thus, a novel series of [3-cis-3,5-dimethyl-(1-piperazinyl)alkyl]bis-(4'-fluorophenyl)amines were synthesized. The most potent compound in this series (9b) displaced [3H]WIN 35,428 binding in rat caudate-putamen (K(i)=17.6nM) with comparable affinity to GBR 12909. Despite high-affinity binding at DAT, and structural similarity to GBR 12909, preliminary studies suggest 9b behaves more like rimcazole than GBR 12909 and does not demonstrate cocaine-like psychostimulant behavior in mice.

Animals↗
PubMed2001

Activation of the RacGTPase inhibits apoptosis in human tumor cells.

The small GTP-binding protein Rac is a downstream effector of the oncogene product p21-ras. Rac is involved in actin polymerization, Jun kinase activation, and intracellular superoxide anion production, through distinct pathways in tumor cells. Here we investigated the role of activated Rac in the response of tumor cells to apoptosis triggered by anti-cancer drugs or the cell surface death receptor CD95. Using M14 melanoma cells stably transfected with a constitutively active form of Rac1, we show that activated Rac inhibits tumor cell response to apoptosis. The inhibitory effect of activated Rac on apoptotic signaling is mediated by the interaction of Rac with intracellular oxidase and the subsequent production of superoxide, which is supported by experiments performed with M14 and NIH3T3 cells transiently transfected with the loss-of-function mutants of Rac in an activated RacV12 background. Consistent with these findings, we also demonstrate that inhibition of the Rac pathway in the HaRas-expressing T24 bladder carcinoma cell line induces a decrease in superoxide anion concentration, and results in a significant increase in tumor cell sensitivity to apoptosis. These findings demonstrate the existence of a novel Rac-dependent survival pathway mediated by intracellular superoxide in tumor cells.

3T3 Cells↗
PubMed2001

[N-actyltransferase2 polymorphism in recurrence of colorectal polyps and adenomas].

OBJECTIVE: To observe the polymorphism of metabolizing enzyme N-actyltransferase 2 gene in populations with history of colorectal adenoma and polyp and to explore the relationship between NAT2 gene phenotype and colorectal cancer genetic susceptibility. METHODS: A cohort of 4,076 patients with history of colorectal adenoma or polyp was established Fifty-two cases were randomly selected from those with recurrence more than 2 times during the twenty years' follow-up. Fifty-two without recurrence were randomly selected as controls. DNA was isolated from the lymphocytes of peripheral blood of these 104 subjects. NAT2 polymorphism was detected by PCR-RFLP. RESULTS: The frequency of wild-type NAT2 (Wt/Wt) was significantly higher in control group (17/52, 32.7%) than in recurrence group (8/52, 15.4%) (P < 0.05). The frequency of heterogeneity type of NAT2 was significantly higher in recurrence group (40/52, 76.9%) than in control group (30/52, 57.7%) (P < 0.05). If OR of wild-type NAT2 (Wt/Wt) was 1, OR of Wt/M* genotype was 2.96 (95% CI: 1.091-8.009), and OR of M*/M* genotype was 2.125 (95% CI: 0.666-6.781). There was no difference of distribution between rapid enzyme type and slow enzyme type in the two groups. CONCLUSION: The frequency of wild-type NAT2 gene (Wt/Wt) is significantly higher in patients without recurrence of adenoma or polyp than in patients with recurrence. The frequency of heterogeneity genotype of NAT2 is significantly higher in patients with recurrence of adenoma or polyp than in those without recurrence. Wild-genotype (Wt/Wt) may be a protection factor in recurrence of colorectal adenomas. No difference can be seen between the distribution of rapid and slow enzyme types in these two groups.

Adenomatous Polyposis Coli↗
PubMed2001

RBP1L1, a retinoblastoma-binding protein-related gene encoding an antigenic epitope abundantly expressed in human carcinomas and normal testis.

BACKGROUND: Antibodies isolated from cancer patients have been used to identify genes encoding tumor-associated antigen epitopes relevant to immune responses in cancer patients. In this report, we used an immunoglobulin G (IgG) purified from serum of a patient with breast cancer to identify its corresponding epitope, gene, and protein-retinoblastoma-binding protein-1-like protein-1 (RBP1L1)-and determined whether it is a potential molecular marker for various cancers. METHODS: IgG purified from the serum of a patient with breast cancer was used to screen an MCF-7 breast cancer cell complementary DNA (cDNA) expression library for immunoreactive clones. The cDNAs identified were cloned and sequenced. Immunoreactivity of specific amino acids in the epitope was determined by western blot analysis and enzyme-linked immunosorbent assay. The cellular location of the antigen was determined by immunoperoxidase staining with purified RBP1L1-specific IgG. Gene expression in various human carcinomas and normal tissues was examined by northern blot analysis and the reverse transcription-polymerase chain reaction. RESULTS: Our purified IgG recognized just one epitope on RBP1L1. The complete 5802-base-pair RBP1L1 cDNA encodes a 1226-amino acid protein containing the antigenic epitope IKPSLGSKK. The derived protein sequence of RBP1L1 shares 74% and 37% amino acid identity, respectively, with a partial sequence of the retinoblastoma-binding protein and the complete sequence of retinoblastoma-binding protein-1. The RBP1L1 epitope was localized to the cytoplasm of MCF-7 cells but was not detected in peripheral blood mononuclear cells. High expression of RBP1L1 messenger RNA was found in human breast, lung, colon, pancreatic, and ovarian cancers and in normal testis, but expression was limited in other normal tissues. CONCLUSIONS: RBP1L1 appears to be a molecular marker associated with a broad range of human malignancies.

Biomarkers, Tumor↗
PubMed2001

Kinetic modulation of Kv4-mediated A-current by arachidonic acid is dependent on potassium channel interacting proteins.

The Kv4 subfamily of voltage-gated potassium channels is responsible for the transient A-type potassium current that operates at subthreshold membrane potentials to control membrane excitability. Arachidonic acid was shown recently to modulate both the peak amplitude and kinetics of the hippocampal A-current. However, in Xenopus oocytes, arachidonic acid only inhibited the peak amplitude of Kv4 current without modifying its kinetics. These results suggest the existence of Kv4 auxiliary subunit(s) in native cells. We report here a K-channel interacting protein (KChIP)-dependent kinetic modulation of Kv4.2 current in Chinese hamster ovary cells and Kv4.2 and Kv4.3 currents in Xenopus oocytes by arachidonic acid at physiological concentrations. This concentration-dependent effect of arachidonic acid resembled that observed in cerebellar granule neurons and was fully reversible. Other fatty acids, including a nonhydrolyzable inhibitor of both lipooxygenase and cyclooxygenase, 5,8,11,14-eicosatetraynoic acid (ETYA), also mimicked arachidonic acid in modulating Kv4.3 and Kv4.3/KChIP1 currents. Compared with another transient potassium current formed by Kv1.1/Kvbeta1, Kv4.3/KChIP1 current was much more sensitive to arachidonic acid. Association between KChIP1 and Kv4.2 or Kv4.3 was not altered in the presence of 10 microm ETYA as measured by immunoprecipitation and association-dependent growth in yeast. Our data suggest that the KChIP proteins represent a molecular entity for the observed difference between arachidonic acid effects on A-current kinetics in heterologous cells and in native cells and are consistent with the notion that KChIP proteins modulate the subthreshold A-current in neurons.

5,8,11,14-Eicosatetraynoic Acid↗
PubMed2001

Human CARD12 is a novel CED4/Apaf-1 family member that induces apoptosis.

The CED4/Apaf-1 family of proteins functions as critical regulators of apoptosis and NF-kappaB signaling pathways. A novel human member of this family, called CARD12, was identified that induces apoptosis when expressed in cells. CARD12 is most similar in structure to the CED4/Apaf-1 family member CARD4, and is comprised of an N-terminal caspase recruitment domain (CARD), a central nucleotide-binding site (NBS), and a C-terminal domain of leucine-rich repeats (LRR). The CARD domain of CARD12 interacts selectively with the CARD domain of ASC, a recently identified proapoptotic protein. In addition, CARD12 coprecipitates caspase-1, a caspase that participates in both apoptotic signaling and cytokine processing. CARD12 may assemble with proapoptotic CARD proteins to coordinate the activation of downstream apoptotic and inflammatory signaling pathways.

Animals↗
PubMed2001

[Structure and expression of colorectal cancer related Immunoglobulin novel gene SNC73].

OBJECTIVE: To study the structure and function of a colorectal cancer-associated gene SNC73 obtained by subtractive hybridization technique. METHODS: Direct sequencing was performed on cDNA of SNC73 gene. In situ-max fluorescence in situ hybridization was used in chromosome mapping of SNC73. Expression of SNC73 in various cancer cell lines and differential expression between normal mucosa and colorectal cancer tissue were examined by Northern blotting and RT-PCR. Expression of SNC73 in colorectal epithelium was detected by in situ hybridization and in situ PCR. RESULTS: Open reading frame prediction showed that SNC73 encodes a peptide identical to the constant region of an IgA molecule in the carboxyl-terminus. The gene was mapped to human chromosome 14q32. The expression of SNC73 in colorectal cancer tissue and that in normal mucosa was different (P < 0.05). SNC73 was lowly expressed in colorectal epithelium. CONCLUSION: Decrease in SNC73 expression may be a potential genetic marker for the development of colorectal cancer. An immunoglobulin alpha-1 gene can be expressed in non-lymphoid cells.

Blotting, Northern↗
PubMed2001

Single molecule tracking of heterogeneous diffusion.

The mean square displacement of heterogeneous diffusion obeys the Einstein relation, thereby showing no sign of heterogeneities in the ensemble measurement of the diffusion constant. The signature of spatial heterogeneities appears in the time evolution of the non-Gaussian distribution and in the cross correlation between the square displacements at different times, both available from single molecule diffusional trajectories. As a quantitative measure, the non-Gaussian indicator g(t) decays asymptotically to zero according to 1/t for finite time correlation, but saturates at a plateau value for power-law correlation. In addition, the joint moment correlation function f(t,tau) provides a direct probe of the memory effect of the fluctuating rate constant. A two-state diffusion model and a stochastic Gaussian model are constructed to evaluate these quantities and are shown to yield the same result within the second cumulant expansion.

Journal Article↗
PubMed2001

Varied ecological environment and fluorosis in Tibetan children in the nature reserve of Mount Qomolangma.

To determine the extent of brick tea consumption fluorosis in children living at elevations of 2000 and 4300 m, 519 children aged 8-15 years living in Xiege'er Town at 4300 m and Zhangmu Town at 2000 m were examined for dental fluorosis, their urinary fluoride concentration was determined, their dietary structure investigated, and the fluoride concentrations of various foods, freshwaters, soils, and fuels determined. Fifteen Tibetan families living in these two areas of the nature reserve of Mount Qomolangma were studied according to UNEP, FAO, and WHO guidelines for the study of dietary intake of chemical contaminants, Horowitz's classification and examination of dental fluorosis, and Dean's dental fluorosis index. The results demonstrated that dental fluorosis in Tibetan children living at an elevation of 2000 m was significantly lower than that of children at 4300 m (P<0.01). Higher elevation can worsen the extent of fluorosis, leading to retention of fluoride in tissues as a result of hypoxia, but fluorosis can also be associated with the deterioration of the ecological environment at high elevation and a low-level economy. Beverages and foods mixed with brick tea water are responsible for the dental fluorosis in the children.

Adolescent↗
PubMed2001

Tumorigenic potential of extracellular matrix metalloproteinase inducer.

Extracellular matrix metalloproteinase inducer (EMMPRIN), a glycoprotein present on the cancer cell plasma membrane, enhances fibroblast synthesis of matrix metalloproteinases (MMPs). The demonstration that peritumoral fibroblasts synthesize most of the MMPs in human tumors rather than the cancer cells themselves has ignited interest in the role of EMMPRIN in tumor dissemination. In this report we have demonstrated a role for EMMPRIN in cancer progression. Human MDA-MB-436 breast cancer cells, which are tumorigenic but slow growing in vivo, were transfected with EMMPRIN cDNA and injected orthotopically into mammary tissue of female NCr nu/nu mice. Green fluorescent protein was used to visualize metastases. In three experiments, breast cancer cell clones transfected with EMMPRIN cDNA were considerably more tumorigenic and invasive than plasmid-transfected cancer cells. Increased gelatinase A and gelatinase B expression (demonstrated by in situ hybridization and gelatin substrate zymography) was demonstrated in EMMPRIN-enhanced tumors. In contrast to de novo breast cancers in humans, human tumors transplanted into mice elicited minimal stromal or inflammatory cell reactions. Based on these experimental studies and our previous demonstration that EMMPRIN is prominently displayed in human cancer tissue, we propose that EMMPRIN plays an important role in cancer progression by increasing synthesis of MMPs.

Animals↗
PubMed2001

Development of brief methods to classify individuals by PROP taster status.

The purpose of this study was to develop brief methods for classifying individuals by genetic taste sensitivity to 6-n-propylthiouracil (PROP). Two methods are described, which are modifications of a commonly used, suprathreshold procedure. Eighty-nine adult subjects rated the perceived intensity of solutions of 0.032, 0.32 and 3.2 mmol/l PROP and 0.01, 0.1, 1.0 mol/l sodium chloride (NaCl) (three-solution test), as well as solutions of 0.32 mmol/l PROP and 0.1 mol/l NaCl (one-solution test) using the Labeled Magnitude Scale (LMS). Subjects were classified as PROP nontasters (n=22), medium tasters (n=51) or supertasters (n=16) by the three-solution test. Taster status was independently determined by the one-solution test using numerical cutoff scores, which were determined by calculating the +/-95% confidence interval around the group means for PROP taste intensity. Supertasters gave PROP a rating of > or =51 ("very strong" on the LMS) and nontasters gave PROP a rating of < or =15.5 (approximately "moderate" on the LMS). Medium tasters fell between these two limits. Ninety-one percent of nontasters, 82% of medium tasters and 89% of supertasters were classified in a similar way by the two methods. Agreement between methods was high [coefficient of association (P)=0.74; P < or =.001]. These data suggest that three- and one-solution methods can reliably classify subjects by taste sensitivity to PROP and could provide valuable tools in population-based studies.

Adolescent↗
PubMed2001

Lake ecosystem health assessment: indicators and methods.

A set of ecological indicators including structural, functional, and system-level aspects were proposed for a lake ecosystem health assessment, according to the structural, functional, and system-level responses of lake ecosystems to chemical stresses including acidification, eutrophication and copper, oil and pesticide contamination. The structural indicators included phytoplankton cell size and biomass, zooplankton body size and biomass, species diversity, macro- and micro-zooplankton biomass, the zooplankton phytoplankton ratio, and the macrozooplankton microzooplankton ratio. The functional indicators encompassed the algal C assimilation ratio, resource use efficiency, community production, gross production/respiration (i.e. P/R) ratio, gross production standing crop biomass (i.e. P/B) ratio, and standing crop biomass unit energy flow (i.e. B/E) ratio. The ecosystem-level indicators conisisted of ecological buffer capacities, energy, and structural energy. Based on these indicators, a direct measurement method (DMM) and an ecological modeling method (EMM) for lake ecosystem health assessment were developed. The DMM procedures were designed to: (1) identify key indicators; (2) measure directly or calculate indirectly the selected indicators; and, (3) assess ecosystem health on the basis of the indicator values. The EMM procedures were designed to: (1) determine the structure and complexity of the ecological model according to the lake's ecosystem structure; (2) establish an ecological model by designing a conceptual diagram, establishing model equations, and estimating model pararmeters; (3) compare the simulated values of important state variables and process rates with actual observations; (4) calculate ecosystem health indicators using the ecological model; and, (5) assess lake ecosystem health according to the values of the ecological indicators. The results of a case study demonstrated that both methods provided similar results which corresponded with the lake's actual trophic state.

Animals↗
PubMed2001

Factors affecting ammonia volatilisation from a rice-wheat rotation system.

Some of the major factors influencing ammonia volatilisation in a rice wheat rotation system were studied. A continuous airflow enclosure method was used to measure NH3 volatilisation in a field experiment at an agricultural college in Jiangsu Province. The five treatments comprised application rates of 0, 100, 200 or 300 kg N ha(-1) as urea, per growing season with rice straw amendment when wheat was sown, and 200 kg N ha(-1) without rice straw amendment. There were three replicates in a randomised block design. Ammonia volatilisation was measured immediately after urea application in the three consecutive years 1995 to 1997. The results show that N losses through NH3 volatilisation accounted for 4-19% of N applied during the wheat growing season and for 5-11% during the rice growing season. Ammonia volatilisation was affected significantly by soil moisture and temperature before and after fertiliser application during the wheat growing season. The ratio of volatilised NH3-N to applied N after urea application during the rice growing season was as follows: top-dressing at the onset of tillering > top-dressing at the start of the booting stage > basal fertilization. The results also show that the amount of N lost through NH3 volatilisation increased with increasing N application rate, but the ratio to applied N was not affected significantly by N application rate. Amendment with rice straw had no significant effect on NH3 volatilisation.

Agriculture↗
PubMed2001

Simulation of acid-base condition and copper speciation in the fish gill microenvironment.

pH, alkalinity, and mucus content in the fish gill microenvironment of carp (Cyprinus carpio) were measured by exposing fish to copper at various water pH levels using an apparatus which separates inspired and expired water. The relationship between pH levels inside and outside of the gill microenvironment, between pH and alkalinity, and between mucus secretion, pH, and copper exposure concentration were modeled. Copper speciation in the surrounding water and in the fish gill microenvironment was simulated using MINTEQA2 chemical equilibrium calculation software. The results of the modeling for pH, alkalinity, and mucus calculation were then adopted as inputs for purposes of parameter identification in the speciation modeling. The differences observed in the copper species distribution between that of the fish gill microenvironment and the surrounding water were based on the speciation modeling. The change in copper bioavailability for fish uptake was also examined. The results indicate the presence of an experimental pH balance point at 6.9, where the pH in the fish gill microenvironment is identical to that of the surrounding water. The observed deviation range in pH levels between that found at the gills and that of the surrounding water varied from -0.4 to 0.8 units. A sinusoidal model was developed for calculation of gill pH based on the pH of the surrounding water. Models calculating alkalinity either in the gill microenvironment or in the surrounding water and for estimating mucus secretion were also developed. The results of the chemical equilibrium calculations demonstrate that, within a pH range of 6-9, the dominant species of copper in bulk solution shifted from free ions to that of the hydroxo complex. With respect to the fish gill microenvironment, the dominant species found under acidic conditions were the mucus copper complex and free ions. Because of the influence of mucus complexation and pH change, bioavailable copper species in the fish gill microenvironment were significantly lower than that in the bulk solution, especially under acidic conditions.

Acid-Base Equilibrium↗
PubMed2001

Prevention of brick tea fluorosis in rats with low-fluoride brick tea on laboratory observation.

To test whether low-fluoride brick tea can prevent the occurrence of fluorosis, rats had access only to a specially prepared low-fluoride brick tea for 1 year. The daily fluoride intake, fluoride metabolism, tissue distribution and development of tooth fluorosis were observed at 4-monthly intervals, at the end of months 4, 8 and 12, respectively. Rats drinking ordinary brick tea (F- 503.5 mg/kg) served as control. The daily intake of fluoride in the ordinary brick tea group was 0.3 mg, and this group developed dental fluorosis characterized as brown and white horizontal marks at the end of month 8, and white chalky dental fluorosis developed at the end of month 12. The total incidence was 75%. In contrast, the daily fluoride intake of the low-fluoride brick tea (F- 210 mg/kg) group was 0.19 mg, and this group did not develop any signs of dental fluorosis. Fluoride distribution was mainly retained in the bone tissue, and about half of the absorbed fluoride was excreted via urine and feces. The results suggest that this low-fluoride brick tea did not induce fluorosis in rats and can be used as an effective control measure for humans.

Age Factors↗