Biomedical subjects
Publications and source records attributed to J Zheng.
The root of Sarcococca vagans Stapt (Buxaceae) is well-known Chinese folk drug called as "Jie Gu Mu", distributed in southern of China. They are used in treatment of traumatic injury. Four new steroidal alkaloids, named sarcovagine A, B, C and D, were isolated from the root of Sarcococca vagans. Their structures were established on the basis of spectral evidence.
Rabies virus 5aG strain (5aGRV) is used to produce primary hamster kidney tissue culture vaccine against Rabies in China. Nucleoprotein (NP), an important constituent of rabies virus, can intrigue Th cell and induce B cell to produce antibody. In order to study the molecular and biological characteristics of 5aG NP, we have cloned and sequenced the nucleoprotein gene. First, total RNA was extracted from infected mouse brain by Guanidine Isothiocyanate one-step method, then the first strand cDNA was synthesized by reverse transcription with oligo (dT) 18 as primer. After RACE (Rapid Amplification of cDNA Ends), one pair of oligonucleotide primers designed referring to the nucleoprotein gene of other strains, were used in PCR to amplify the fragments of nucleoprotein gene (1.4kb). When these fragments were inserted into vector pUC18, sequences of the nucleoprotein gene were obtained by double-stranded sequencing. Comparing the nucleic acid and deduced amino acid sequence of 5aGRV nucleoprotein gene with available NP sequences of other RV strains, we found that the nucleoprotein has less variation than glycoprotein, so nucleoprotein is more suitable to be used as a diagnostic reagent and a subunit vaccine.
A systematical investigation of the retention behaviour of arsenic compounds (arsenite, arsenate, methylarsonic acid, dimethylarsinic acid, arsenobetaine etc.) on PRP-X100 column under alkaline condition was carried out. The dependence of the retention times of arsenic compounds on pH with two mobile phases: 20 mmol/L ammonium bicarbonate, 2.5 mmol/L p-hydroxybenzoic acid/1.0 mmol/L benzoic acid was studied, and the optimal separations of these five arsenic compounds were achieved.
A method for qualitative and quantitative analysis by GC/MS and GC of ethers and related olefines in light gasoline from catalytic cracking before and after etherification has been presented. By means of the analysis of the reactive olefines and the ethers produced it is concluded that six kinds of olefines had taken part in the etherification process, they were, 2-methyl propene-1,2-methyl butene-2,2-methyl butene-1,2-methyl pentene-1,2-ethyl butene-1, and 2-methyl pentene-2, and the four ethers produced were 2-methoxy-2-methyl propane, 2-methoxy-2-methyl butane, 2-methoxy-2-methyl pentane and 3-methoxy-3-methyl pentane. These ethers are all contributing to enhance the octane number.
A high performance liquid chromatographic method has been successfully used to separate and determine the six drugs in an anticold solution. In the anticold solution, potassium guaiacol sulfonate, acetaminophen, D,L-methylephedrine, and caffeine were analyzed with a column of Zorbax ODS, by using the mobile phase of MeOH-0.05 mol/L KH2PO4-H3PO4 (250 : 750 : 0.5) and UV detector at 214 nm, dextromethorphan HBr and chlorpheniramine maleate were analyzed with the same column, by usingthe mobile phase of MeOH-H2O-HsPO4-SLS (80 : 20 : 0.5 : 0.2) and UV detector at 260 nm. This method is proved to be very effective to separate the six drugs mentioned above. For potassium guaiacol sulfonate, acetaminophen, D,L-methylephedrine, caffeine, dextromethorphan HBr and chlorpheniramine, the response values were linear between 1.0-10 microg, 5.0-50 microg, 0.25-2.5 microg, 0.5-5 microg, 0.25-2.5 microg, 0.05-0.5 microg respectively and the recoveries were 100.53% +/- 1.12%, 100.19% +/- 0.58%, 99.4% +/- 1.60%, 99.55% +/- 1.01%, 99.37% +/- 1.52%, 99.01% +/- 1.20% (n=5) respectively.
This study is about the influences of tetraazaindene (TAI) on absorption spectra and the fluorescence spectra of three kinds of sensitizing dyes. The absorption of all peaks of the dyes enhance with increasing TAI, among which the absorption of J-aggregate has even marked enhancement. At certain value of TAI, the absorption of monomolecule of dye enhances much more rapidly as well as the absorption of H-aggegte decreasing because of H-aggregate dissociating into monomolecules. The results obtained also show that the fluorescence emissions of the dyes enhance with increasing TAI. The mechnisms of the observed phenomena are discussed in detail.
A whole-blood test for total cholesterol has been developed that is performed in a low-cost disposable flow device without user intervention (after sample addition). The device meters the sample, separates plasma from erythrocytes, and precisely times plasma flow into various reagent compartments, including a quality-assurance chamber. Test results are displayed as a well-defined and easily readable color bar. A quality-control window attests to the integrity of the test components. Here, we describe the assembly and individual functions of the device and report its performance characteristics. Precision and accuracy studies in four clinical studies at independent locations yielded total imprecision of <5% and an average bias of 1.35% vs the Abell-Kendall method.
Application of differential display to the comparison of androgen-stimulated and unstimulated human prostate carcinoma cell line LNCaP identified androgen induction of the L-plastin gene, which encodes an actin-binding protein isoform. Further investigation demonstrated that L-plastin expression in LNCaP cells is up-regulated by both dihydrotestosterone and estradiol. This induction of expression is detected as early as 2 hours after addition of steroids to the cell culture. L-plastin expression is also detected in other prostate carcinoma cell lines by reverse transcriptase polymerase chain reaction and immunohistochemistry but not in the single normal adult prostate epithelial cell line that is available to us. Analysis of multiple primary prostatic tumor tissues as well as normal and tumor tissues of the same prostate gland showed that tumor tissues exhibit a higher level of expression as compared with the normal tissues. Immunohistochemical study using anti-L-plastin antiserum on normal and carcinomatous prostate tissues showed a very striking difference in the staining patterns. Positive staining was seen in the fibromuscular stroma in normal prostates but not in the glandular epithelial cells. In contrast, strong staining was seen predominantly within the carcinomatous glandular epithelial cells. Taken together, these results suggest that the expression of L-plastin in prostatic epithelial cells is linked to the malignant state and that, once expressed in carcinomas, its expression is regulated by steroid hormone receptors.
HIV enters the brain soon after virus exposure but elicits profound neurological deficits in infected humans years later usually during progressive immunosuppression and the development of the acquired immune deficiency syndrome. The neurological disease complex associated with virus infection occurs in a large proportion of infected patients and is commonly referred to as HIV-1 associated dementia complex. The neuropathogenesis of central nervous system/viral infection revolves around mononuclear phagocytes (brain macrophage/microglial) infection and immune activation in brain. Macrophages secrete neurotoxic factors that elicit neuronal injury and inevitably death leading to the constellation of cognitive and motor impairments common during progressive disease. Neurotoxic factor production requires virus entry and replication, the evolution/selection of neurovirulent HIV-1 strains and the production of viral and cellular immune factors injurious to human neurons. Interestingly, neurological deficits, the HIV-1 associated neuropathology and viral replication disease are not always associated. This has led to the notion that viral replication induces the autocrine/paracrine production of cellular/viral factors leading to a metabolic encephalopathy. Anti-retroviral and anti-inflammatory therapies should prove increasingly beneficial for treatment and, ultimately, reversal of HIV-1 associated dementia complex in the affected human host.
OBJECTIVE: To provide the scientific basis for formulating the control strategies of schistosomiasis japonica in mountainous regions in China Schistosomiasis Control Programme. METHODS: We selected Chuanxing Village in Sichuan Province and Zhonghe Village in Yunnan Province as the two pilot areas for an epidemiological investigation according to their geographical and topographical characteristics, i.e. plateau canyon and plateau basin, respectively. Concentrated-egg hatching method in nylon tissue bag and Kato-Katz technique were used for the survey on prevalence rate and intensity of infection of man and domestic animals. Questionnaires were applied to investigating the infection sources, community behavior and the socioeconomic status. Snail survey and detection of cercaria-infested water bodies were conducted using routine techniques. RESULTS: The results showed that in the endemic areas with plateau canyon, the key infection source was cattle. The infection rate in women was higher than that in men. The pattern of water-pollution was wild feces and the pollution source was cattle feces. Snails and infectious snails were distributed over the rice fields and the resident was infected through production activities. In plateau basin, the key infection source was human beings. The infection rate in men was higher than that in women. The pattern of water pollution was fertilization. The pollution source was human feces. Snails and infectious snails were distributed over the canals and ditches and the resident was infected through production and daily activities. CONCLUSIONS: Therefore, it was suggested that the mountainous endemic areas should be divided into two sub-types, i.e., plateau basins and plateau canyons. The different control strategies should be formulated in accordance with the environmental situations and socioeconomic factors in the two kinds of endemic areas.
OBJECTIVES: To detect the activity of interleukin-6 (rhIL-6) on human lung cancer and the influences of recombinant human IL-6 (rhIL-6) on the in vitro growth of high-metastatic human lung giant cell carcinoma cell line PG and low-metastatic human lung adenocarcinoma cell line PAa. METHODS: The effects of rhIL-6 on the expressions of IL-6, IL-6R, c-myc, c-fos and c-jun mRNAs were analyzed by Northern blotting hybridization. RESULTS: rhIL-6 could stimulate the in vitro growth of both PG and PAa cells, in a dose-and-time-dependent manner. Both PG and PAa cells were shown to express IL-6 and IL-6R identified by reverse transcription PCR analysis. Northern blotting hybridization revealed that rhIL-6 up-regulated mRNA levels of IL-6, IL-6R and c-myc rather than those of c-fos and c-jun. CONCLUSION: These data suggest that rhIL-6 may promote the proliferation of human lung cancer cell lines PG and PAa, which might, at least partly, be related to the up-regulation of expressions of IL-6, IL-6R, c-myc gene transcript.
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We now summarize key issues that we have investigated and highlight additional areas that need to be addressed. We are interested in two basic aspects of the GHRH pathway, those occurring in the brain, involving the synthesis of GHRH, and those occurring in the pituitary, involving signaling by GHRH. We have a long-term interest in the activity and regulation of the hypothalamic neurosecretory cells that synthesize GHRH. With respect to human disease, it is interesting that, despite the primal role played by GHRH in growth-hormone secretion, no mutations in the GHRH gene have yet been identified in association with growth disorders. Focusing on the downstream signaling components of the GHRH pathway, we now know quite a lot about the structure of the GHRH receptor and about some aspects of the signal transduction pathways that mediate the actions of GHRH. With respect to human disease, we have found that in an animal model, the little mouse, a mutation of the GHRH receptor results in growth-hormone deficiency and a dwarf phenotype, and there are ongoing attempts in several laboratories to try to identify similar inactivating mutations in the GHRH receptor in patients with isolated growth-hormone deficiency. Conversely, there is also substantial interest in whether activating mutations in this receptor might be identified in patients with growth-hormone-secreting pituitary tumors. We are also interested in whether there are additional receptors that might mediate some of the extrapituitary actions of GHRH. Finally, a major direction we are taking in the laboratory at the present time is toward understanding the developmental, hormonal, and tissue-specific regulation of the GHRH receptor gene.
Pituitary adenylate-cyclase-activating polypeptide (PACAP) has been shown to possess mitogenic activity in various tumor cells. The present study was designed to investigate signal transduction mechanisms and expression of the proto-oncogenes c-fos and c-jun linked to the mitogenic effect of PACAP in the pancreatic carcinoma cell line AR4-2J. PACAP-(1-27)-peptide and PACAP-(1-38)-peptide, but not the structurally related vasoactive intestinal polypeptide (VIP), potently stimulated [3H]thymidine incorporation and cell number at doses of 0.1-10 nM. Both molecular forms of PACAP strongly increased formation of cAMP and inositol trisphosphate, elevated cytosolic Ca2+ levels and induced mitogen-activated protein (MAP) kinase activity. Quantitative reverse-transcription PCR revealed that PACAP-(1-27)-peptide and PACAP-(1-38)-peptide elevated c-fos mRNA levels 50-100-fold, whereas c-jun mRNA levels increased only moderately (2-3-fold). The effect of PACAP on c-fos and c-jun expression in AR4-2J cells was rapid (20 min), transient (1-2 h), dose-dependent IC50, 0.5 nM) and was abolished by the specific PACAP receptor antagonist PACAP-(6-38)-peptide or inhibitors of protein kinase C or tyrosine kinases. Compared with PACAP, epidermal growth factor and gastrin equipotently stimulated c-fos transcription whereas VIP, secretin, forskolin or phorbolester showed only marginal effects. Both PACAP (1-27)-peptide and PACAP-(1-38)-peptide strongly increased the DNA binding activity of the c-fos/ c-jun heterodimer transcription factor AP-1 at 10 nM and also stimulated AP-1 transcriptional activity up to 20-fold in AR4-2J cells. These findings indicate that the mitogenic effect of PACAP mediated via activation of the GTP-binding protein coupled PACAP/VIP-1 (PV1) receptor is linked to the MAP kinase cascade, increased expression of the proto-oncogenes c-fos and c-jun and activation of the heterodimeric transcription factor AP-1.
A haloenol lactone derivative has been synthesized and found to be an isozyme-selective and active site-directed inactivator of glutathione S-transferase (GST). Preincubation of the haloenol lactone (100 microM) with murine Alpha, Mu, or Pi GST isozyme (1.0 microM) at pH 6.5, 37 degrees C resulted in time-dependent loss of enzyme activity with highly selective inhibition of the Pi isozyme (t1/2, approximately 2 min). In a separate experiment, a 10-fold excess of the lactone was incubated with GST-Pi isozyme at 37 degrees C for 3 h, followed by dialysis against Nanopure water. GST activity lost upon incubation with the lactone could not be restored by exhaustive dialysis, and only 8% of enzyme activity for the modified GST remained relative to the control that was treated identically except the lactone was omitted from the incubation. Both control and modified GST were characterized using electrospray ionization mass spectrometry. No native GST (23,478 Da) was observed in the spectrum of modified GST. Instead, protein incubated with the lactone exhibited an increase in molecular mass of 230 Da relative to control GST. The lactone (100 microM) was incubated with GST Pi isozyme (1.0 microM) in the presence of the competitive inhibitor S-hexylglutathione (10 microM), which suppressed time-dependent inhibition of GST by the lactone. The results suggest that this haloenol lactone is an irreversible and active site-directed inhibitor of GST that appears to inhibit the enzyme through two consecutive steps of nucleophilic attack.
The proteoglycan, aggrecan has a globular domain, G1, at the N terminus and a different globular domain, G3, at the C terminus. Aggrecan produced by mutant nanomelic chickens is truncated due to a premature stop codon and consequently lacks G3 and a minor portion of its chondroitin sulfate domain (Li, H., Schwartz, N. B., and Vertel, B. M.(1993) J. Biol. Chem. 268, 23504-23511). The mutant protein is retained in the endoplasmic reticulum and fails to enter the Golgi stacks (Vertel, B. M., Walters, L. M., Grier, B., Maine, N. , and Goetinck, P. F.(1993) J. Cell Sci. 104, 939-948). The homozygous mutant is lethal because of failure of chondrogenesis and osteogenesis, while the heterozygous mutant is dwarfed. To further elucidate the pathogenetic mechanisms underlying nanomelia and to determine if G1 and G3 are themselves secreted, we expressed them in transfected host cells. Expression was performed in wild type Chinese hamster ovary (CHO) cells and in mutant CHO cells which are unable to link glycosaminoglycan (GAG) chains to core proteins. We compared: (a) secretion of expressed G1 and G3 constructs containing contiguous GAG chain consensus sites and (b) GAG chain modification of the secreted proteins. We find that: 1) G3 is 24-100 times more rapidly secreted than G1; 2) secreted G3 contains contiguous chondroitin sulfate GAG chains, while secreted G1 lacks contiguous GAG chains; 3) G3 secretion is not coupled to xylosylation of contiguous GAG chain consensus sites. These results imply that G1 and G3 intrinsically differ in passage through the cell secretory route.
BACKGROUND: Ovarian epithelial tumors can be divided into subcategories often regarded as different stages of neoplastic transformation. Cystadenomas belong to the least aggressive subgroup and are noninvasive and nonmetastatic. Ovarian tumors of low malignant potential (LMP) are intermediate between cystadenomas and carcinomas and show markedly reduced invasive and metastatic abilities. Invasion and metastasis are the hallmarks of carcinomas, which constitute the most aggressive subgroup and can be further subdivided into different grades. PURPOSE: We performed comparative allelotype analyses of ovarian cystadenomas, LMP tumors, and carcinomas, reasoning that such analyses could provide clues about the molecular determinants of their phenotypic differences. Because we realized that allelic losses involving the X chromosome might be associated with LMP tumor development, we determined whether such losses were interstitial and whether they involved the active or the inactive X chromosome. METHODS: Frequencies of loss of heterozygosity (LOH) at specific loci in every chromosomal arm were determined in 16 ovarian cystadenomas, 23 ovarian LMP tumors, 15 low-grade ovarian carcinomas, and 35 high-grade ovarian carcinomas by use of either the polymerase chain reaction (PCR) or Southern blot analyses. We took advantage of the fact that DNA methylation is an important mechanism of X-chromosome inactivation to determine whether losses involving the X chromosome were in the active or the inactive copy. We analyzed the methylation status of retained alleles on the X chromosome by determining whether they could be amplified by PCR after digestion with the methylation-sensitive restriction endonuclease Hpa II. RESULTS: High-grade carcinomas contained frequent(>50%) LOH in four autosomal chromosome arms, i.e., 6q, 13q, 17p, and 17q. Except for 13q, these same chromosomal arms showed frequent LOH in low-grade carcinomas. LOH in autosomal chromosomes was comparatively rare in LMP tumors and was absent in cystadenomas. In contrast, half (eight of 16) of LMP tumors informative for a locus in the proximal portion of chromosome Xq showed LOH at that locus. These losses were the result of interstitial deletions in six of the eight cases and involved the inactive copy of the X chromosome exclusively. Similar losses in the X chromosome were not seen in either cystadenomas or low-grade carcinomas. CONCLUSIONS AND IMPLICATIONS: LOH at multiple loci is associated with the development of ovarian carcinomas but not with the development of cystadenomas and LMP tumors. However, the integrity of a locus in chromosome Xq that possibly escapes X-chromosome inactivation is important for the control of LMP tumor development. The fact that this locus does not appear to be involved in the genesis of low-grade carcinomas suggests that LMP tumors are not precursors of such carcinomas.
Insulin was immobilized on a surface-hydrolyzed poly(methyl methacrylate) film. Chinese hamster ovary cells overexpressing human insulin receptors were cultured on the film in the absence of serum or soluble proteins. Small amounts of immobilized insulin (1-10% of the required amount of free insulin) were sufficient to stimulate cell proliferation. In addition, the maximal mitogenic effect of immobilized insulin was greater than that of free insulin. Immobilized insulin activated the insulin receptor and downstream signaling proteins, and this activation persisted for longer periods than that obtained with free insulin, probably explaining the greater mitogenic effect of the immobilized insulin. Finally the immobilized-insulin film was usable repeatedly without marked loss of activity.