Biomedical subjects
Publications and source records attributed to Y Gong.
226 cases of psychosis involved in lawsuit were investigated. The problem of forensic identification was discussed. Some suggestions were given to raise the quality of the forensic identification in psychosis.
We studied the early effects of selenium-enriched spiruline (SESP) on radiation-induced pulmonary fibrosis using histopathology, cDNA-mRNA dot-blot hybridization, and a biochemical technique for quantifying the hydroxyproline content. We found marked lung injury in the irradiated group, whereas only slight hyperemia, hemorrhage, exudation, and thickness of the interalveolar wall in the lung in the selenium-treated group. The hydroxyproline (hyp) content in the lungs and the synthesis of type III collagen mRNA decreased in the SESP-treated group. Selenium-enriched spiruline may have a protective effect on the development of radiation pneumonitis.
A personal computer based program (DDAPD1) was developed for calculating or determining the apparent distribution function of a drug to a possibly heterogeneous biophase, the mean transit time of a drug at the biophase, the ratio of distribution clearance to biophase volume of distribution, the drug concentration-time function at the biophase (Cb(t)), and a function which reflects the relationship between the pharmacodynamic response and Cb(t) of the drug. This program uses an approach based on disposition decomposition analysis and the hysteresis minimization principle. The application of the program is demonstrated using published data for heptabarbital.
The stimulus responsible for inducing hepatocytes to enter the cell cycle following partial hepatectomy (PHx) remains to be identified. One suggested candidate is the change in hepatocyte membrane potential (PD) that occurs immediately following PHx. To test this possibility, we monitored changes in hepatocyte PD and immediate-early proto-oncogene expression in rats pretreated with saline or gamma aminobutyric acid (GABA), an amino-acid neurotransmitter that hyperpolarizes isolated hepatocytes. Intraperitoneal injections of saline or GABA (500 microg/g body weight) were administered to adult, male Sprague-Dawley rats 1 hour prior to 70% PHx. Rats were sacrificed and the livers excised at various times until 180 minutes post-PHx for messenger RNA (mRNA) and protein analyses. In additional groups of saline- and GABA-treated rats, PD changes were recorded continuously from -260 to 180 minutes post-PHx. Serum GABA concentrations were determined by ion-exchange chromatography with orthopthaldehyde fluorescence detection. Hepatocyte PD's were recorded in situ by intracellular microelectrodes with an Axoprobe-1A amplifier. Steady-state levels of c-fos, c-jun, jun-B, and c-myc transcripts and proteins were documented by Northern blots of poly(A)-enriched RNA derived from resected livers and Western blots of total nuclear protein, respectively. Serum GABA concentrations remained unchanged in saline-treated controls but increased 10- to 20-fold above baseline values in GABA-treated rats. In saline-treated controls, hepatocyte depolarization occurred immediately and was maintained throughout the 180 minutes post-PHx period (PD pre-PHx, -36.8 +/- 5.1; 15 minutes post-PHx, -27.5 +/- 5.7; and 180 minutes post-PHx, -28.3 +/- 4.4 mV, mean +/- SD); whereas in GABA-treated rats, hepatocyte PD remained unchanged (-37.0 +/- 1.1; -36.4 +/- 3.1 and -39.2 +/- 2.7 mV, respectively). Despite abrogation of hepatocyte PD changes, proto-oncogene mRNA and protein levels in saline- and GABA-treated rats were either similar or, in the case of c-fos and c-jun, increased five- to sevenfold in GABA-treated rats. The results of this study indicate the following: 1) hepatocytes depolarize immediately post-PHx and remain depolarized throughout the priming phase of the cell cycle; 2) elevated serum GABA concentrations prevent PHx-induced hepatocyte depolarization; and 3) depolarization is not the stimulus responsible for priming hepatocytes into replicative competence.
The helix content of a series of peptides containing single substitutions of the 20 natural amino acids in a new designed host sequence, succinyl-YSEEEEKAKKAXAEEAEKKKK-NH2, has been determined using CD spectroscopy. This host is related to one previously studied, in which triple amino acid substitutions were introduced into a background of Glu-Lys blocks completely lacking alanine. The resulting free energies show that only Ala and Glu- prove to be helix stabilizing, while all other side chains are neutral or destabilizing. This agrees with results from studies of alanine-rich peptide modela, but not the previous Glu-Lys block oligomers in which Leu and Met also stabilize helix. The helix propensity scale derived from the previous block oligomers correlated well with the frequencies of occurrence of different side chains in helical sequences of proteins, whereas the values from the present series do not. The role of context in determining scales of helix propensity values is discussed, and the ability of algorithms designed to predict helix structure from sequence is compared.
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The tenascins are a family of large extracellular matrix proteins with at least three members: tenascin-X (TNX), tenascin-C (TNC, or cytotactin) and tenascin-R (TN-R, or restrictin). Although the tenascins have been implicated in a number of important cellular processes, no function has been clearly established for any tenascin. We describe a new contiguous-gene syndrome, involving the CYP21B and TNX genes, that results in 21-hydroxylase deficiency and a connective-tissue disorder consisting of skin and joint hyperextensibility, vascular fragility and poor wound healing. The connective tissue findings are typical of the Ehlers-Danlos syndrome (EDS). The abundant expression of TNX in connective tissues is consistent with a role in EDS, and our patient's skin fibroblasts do not synthesize TNX protein in vitro or in vivo. His paternal allele carries a novel deletion arising from recombination between TNX and its partial duplicate gene, XA, which precludes TNX synthesis. Absence of TNX mRNA and protein in the proband, mapping of the TNX gene and HLA typing of this family suggest recessive inheritance of TNX deficiency and connective-tissue disease. Although the precise role of TNX in the pathogenesis of EDS is uncertain, this patient's findings suggest a unique and essential role for TNX in connective-tissue structure and function.
The effects of L-arginine (L-arg) and sodium nitroprusside (SNP) on pulmonary arterial pressure, the percentage of muscularization of intra-acinar vessels and ultrastructural changes of extra pulmonary artery and pulmonary arteriole of chronically hypoxic rats were studied. The results showed that: (1) Both L-arg and SNP decreased mean pulmonary arterial pressure of chronically hypoxic rats significantly. (2) Both L-arg and SNP reduced the percentage of muscularization of intra-acinar vessels of chronically hypoxic rats significantly. (3) Both L-arg and SNP protected pulmonary artery from the damages of endothelium and the changes in smooth muscle cell phenotype by hypoxia. These results suggested that exogenous nitric oxide might play a role in the protection of pulmonary arterial function and structure which alleviate the development of pulmonary hypertension induced by chronic hypoxia.
IL-2 was introduced into mice B16 melanoma cell line by using retrovirus infection method. Both B16 and B16-IL-2 cells were treated with Mit C beforehand and were then inoculated intraperitoneally as vaccines in mice respectively. Hanks solution was used instead of the vaccine in the control group. The data showed that the tumor incidence rate was zero in the group receiving B16-IL-2 vaccine followed by B16 inoculation. However, incidence rate was 100% in both the B16 vaccine immunization group and in the control groups. Experiments also indicated that the proliferation of splenic lymphocytes induced by MLTR, the specific cytotoxicity of CTL against B16 cells, the activities of splenic NK, LAK, and the level of IL-2 secretion in mice immunized by B16-IL-2 were much higher than those in the mice immunized only with B16 cells as well as the controls. These data indicated that secretion of IL-2 in mice promoted specific and nonspecific anti-tumor immunity of mice. The theoretic basis was provided for IL-2-secreting tumor vaccine.
The performance of chloropropyl bonded silica (CPS) in HPLC and its applications in separation of disubstituted benzene isomers and prostaglandin epimers were studied. The CPS column has high column efficiency and the kinetic curves illustrate it is suitable for fast analysis. The effect of composition and pH value of mobile phase (methanol/water or methanol/20 mmol/L H3PO4-NaOH buffer) on the retention of the solutes were investigated. Generally, the main retention mechanism of solutes was hydrophobic interaction, however there also exited polar adsorption interaction, ion-dipole interaction etc. When the mobile phase condition changed, the main separating mechanism may be changed with CPS column. So, with increasing pH value of mobile phase, the retention of isomers of nitrophenol exhibited a parabolic change. The chromatographic condition was optimized, and the isomers of nitrophenol, aminophenol and toluidine etc. as well as the epimers of 15-methyl-PGF2alpha were separated very well on the column. Moreover, the speed of separation was faster than that in general reversed-phase system. CPS showed to have good stability to heat and solvent and it was also a very stable intermediate to prepare bonded phase with various functional groups.
C57/BL6J mice were inoculated with Lewis lung cancer cells as an experimental model to study the effects of green tea on cancer prevention, inhibition of tumor growth and immune regulation in mice with tumor. Results showed that weight of thymus in C57/BL6J mice and its index declined, proportion of positive CD4 subgroup of T lymphocyte and ratio of CD4+, to CD8+ reduced, baseline chemilumi-nescence decreased in peripheral white blood cells, yeast zymosan stimulated chemiluminescence increased, and number of immunoglobulin M formation cells decreased. It indicated that green tea had obvious inhibition in Lewis lung cancer and protective effects, to various extent, on adverse changes of above indices.
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The solution structure of recombinant Cucurbita maxima trypsin inhibitor-V (rCMTI-V), whose N-terminal is unacetylated and carries an extra glycine residue, was determined by means of two-dimensional (2D) homo and 3D hetero NMR experiments in combination with a distance geometry and simulated annealing algorithm. A total of 927 interproton distances and 123 torsion angle constraints were utilized to generate 18 structures. The root mean squared deviation (RMSD) of the mean structure is 0.53 A for main-chain atoms and 0.95 A for all the non-hydrogen atoms of residues 3-40 and 49-67. The average structure of rCMTI-V is found to be almost the same as that of the native protein [Cai, M., Gong, Y., Kao, J.-L., & Krishnamoorthi, R. (1995) Biochemistry 34, 5201-5211]. The backbone dynamics of uniformly 15N-labeled rCMTI-V were characterized by 2D 1H-15N NMR methods. 15N spin-lattice and spin-spin relaxation rate constants (R1 and R2, respectively) and [1H]-15N steady-state heteronuclear Overhauser effect enhancements were measured for the peptide NH units and, using the model-free formalism [Lipari, G., & Szabo, A. (1982) J. Am. Chem. Soc. 104, 4546-4559, 4559-4570], the following parameters were determined: overall tumbling correlation time for the protein molecule (tau m), generalized order parameters for the individual N-H vectors (S2), effective correlation times for their internal motions (tau e), and terms to account for motions on a slower time scale (second) due to chemical exchange and/or conformational averaging (R(ex)). Most of the backbone NH groups of rCMTI-V are found to be highly constrained ((S2) = 0.83) with the exception of those in the binding loop (residues 41-48, (S2) = 0.71) and the N-terminal region ((S2) = 0.73). Main-chain atoms in these regions show large RMSD values in the average NMR structure. Residues involved in turns also appear to have more mobility ((S2) = 0.80). Dynamical properties of rCMTI-V were compared with those of two other inhibitors of the potato I family--eglin c [Peng, J. W., & Wagner, G. (1992) Biochemistry 31, 8571-8586] and barley chymotrypsin inhibitor 2 [CI-2; Shaw, G. L., Davis, B., Keeler, J., & Fersht, A. R. (1995) Biochemistry 34, 2225-2233]. The Cys3-Cys48 linkage found only in rCMTI-V appears to somewhat reduce the N-terminal flexibility; likewise, the C-terminal of rCMTI-V, being part of a beta-sheet, appears to be more rigid.
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The gene responsible for transcribing glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is commonly used as a reporter gene to estimate the amount of RNA present in Northern analyses. However, recent data suggest that GAPDH gene expression may vary with the extent of cell proliferation and differentiation. 28S-ribosomal RNA (28S-rRNA) has also been employed to normalize Northern blots prepared with total RNA. In the present study, we compared the expression of GAPDH messenger RNA (mRNA) with 28S-rRNA by Northern blot analyses in human hepatocellular carcinoma tissues (HCC) and adjacent non-HCC tissues from eight patients with chronic viral hepatitis-induced cirrhosis and normal liver tissue from eight healthy control subjects. The results of the study revealed that GAPDH mRNA levels in HCC were significantly higher (14X-16x) than those in adjacent non-HCC and normal liver tissues. Conversely, 28S-rRNA levels did not vary among HCC, adjacent non-HCC, and normal liver tissues. We also demonstrated that the 28S-RNA signal was proportional to the amount of RNA loaded. These findings indicate that 28S-rRNA, rather than GAPDH mRNA, should be used as RNA loading controls for Northern blot analyses involving HCC and nontumor tissues. The findings also raise the possibility that GAPDH mRNA gene expression might serve as a diagnostic indicator for human HCC.
The human X-linked steroid sulfatase gene (STS) was among the first genes shown to escape X inactivation. At least fourteen genes regulated in this fashion have now been recognized. They are dispersed into several regions of the X chromosome and may be controlled in a locus specific manner. Studies of the promoters of these genes could provide insights into the mechanism of X inactivation, however little information of this nature is currently available. For this reason we examined 5' flanking sequences of the human STS gene for promoter function. Four transcription start sites scattered over a 50bp region were identified. Functional domains of this TATA-less and GC poor promoter were identified by study of a series of terminal and internal deletions. A putative promoter sequence was identified which by itself exhibits little or no basal activity. However when combined with upstream regulatory elements, this segment showed weak but reproducible activity in a CAT (chloramphenicol acetyltransferase) reporter assay. Several regulatory domains acting as enhancers and repressors were subsequently identified. The relationship of this 5' sequence to the ability of the STS gene to escape X-inactivation is discussed.
Although the human steroid sulfatase (STS) gene has been cloned and characterized in detail, several attempts to clone its mouse homologue, with either anti-human STS antibodies or human STS cDNA probes, have failed, suggesting a substantial divergence between these genes. However, partial amino-terminal sequence from purified rat liver STS is very similar to its human counterpart, and sequence comparisons have revealed several domains that are conserved among all the sulfatases characterized to date. Thus, we used a degenerate-primer RT-PCR approach to amplify a 321-bp fragment from rat liver cDNA, which was used as a probe to clone and characterize the complete cDNA. Comparison of the protein coding region between the rat and human genes showed 66% homology both at the DNA and the protein levels. STS activity was conferred to STS(-) A9 cells upon transfection with a rat Sts expression construct, indicating the authenticity of the cloned cDNA. While Sts has been shown to be located in the mouse pseudoautosomal region, both physical and genetic mapping demonstrate that Sts is not pseudoautosomal in the rat. The overall genomic organization of rat Sts and human STS is very similar, except that the insertion site for intron 1 in the rat is 26 bp upstream from that in the human. Rat Sts is only 8.2 kb long, while the human STS spans over 146 kb.
The noncytopathic Australian bovine viral diarrhoea virus (BVDV) Trangie isolate was used to establish a one-step growth curve and to investigate previously uncharacterized aspects of pestivirus replication. The eclipse phase was found to be approximately 8 to 10 h and the first appearance of viral antigen assayed by immunofluorescence occurred around 6 h post-infection (p.i.). Both positive- and negative-sense virus RNAs were first detected at 4 h p.i. by Northern blot hybridization using strand-specific RNA probes generated by in vitro transcription from cDNA cloned from the NS3 region. The ratio of positive- to negative-sense virus RNA changed from 2:1 at 4 h p.i. to 10:1 at 12 h p.i. and thereafter. The kinetics of synthesis showed that the rate of synthesis of positive-strand viral RNA increased rapidly from 6 h p.i., whereas the rate of synthesis of the negative-strand remained constant. The copy number of genomic RNA determined by Northern blot hybridization analysis was estimated to be 1.5 x 10(4) copies per cell, 16 to 24 h p.i. Viral RNA species that were thought to represent replicative intermediate (RI) and replicative forms (RF) were detected after electrophoretic separation by urea-PAGE. Confirmation of the identity of the RI and RF was obtained using LiCl precipitation and RNase A digestion of [3H]uridine-labelled RNA. Pulse-chase labelling of BVDV-infected cells was consistent with synthesis of nascent BVDV RNA through an RI derived by strand displacement from an RF template and thus the synthesis of BVDV RNA is likely to be similar to the model proposed for flavivirus replication.