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Biomedical subjects

H Zeng

Publications and source records attributed to H Zeng.

At least 127 records · Page 7Linked to original sources
PubMed1998

[Expression of interleukin-8 and its receptor in acute promyelocytic leukemia under all-trans retinoic acid treatment].

OBJECTIVE: To evaluate the clinical significance of expression of interleukin-(IL-8) and its type A receptor(IL-8RA) in acute promyelocytic leukemia(APL) patients under all trans-retinoic acid(ATRA) induction. METHODS: Serum IL-8 level of 18 APL patients were dynamically studied(ELISA). Fresh APL cells from 3 patients were cultured with ATRA(10(-6) mmol/L). Supernatant IL-8 level and IL-8RA expression on APL cells were measured by FACS. RESULTS: In vitro, IL-8 concentrations decreased 72 hours after incubation, while IL-8RA increased. In vivo, IL-8 increased more rapidly and markedly than temperature and WBC counts did before retinoic acid syndrome(RA-S) occurred. Serum IL-6 and IL-8 levels significantly increased when the patients suffered infection, and IL-8 increased even before fever. Both IL-8 and D-dimer increased while DIC progressed. CONCLUSION: ATRA inhibited IL-8 secretion of APL cells while increased the expression of IL-8RA. Monitoring serum IL-8 concentrations could predict the development of RA-S and infection. Increase of both IL-8 and D-dimer concentrations suggested DIC progression.

Adolescent↗
PubMed1998

[Retinoic acid inducing Fas expression in HL-60 cells].

OBJECTIVE: To investigate the effect of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9-cis RA) on the expression of Fas and the sensitivity to anti-Fas induced apoptosis in HL-60 cells. METHODS: Fas expression was detected by flow cytometry. Anti-Fas induced apoptosis (AFIA) was determined by morphological features, DNA fragment electrophoresis, and flow cytometric cell cycle analysis. RESULTS: Fas antigen was weakly expressed on HL-60 cells. After incubation of HL-60 cells with 10(-6) mol/L ATRA or 9-cis RA for 4 days, both the Fas expression and AFIA were significantly enhanced. 9-cis RA was more potent than ATRA in increasing the sensitivity to AFIA. CONCLUSION: RA might upregulate Fas expression. Further elucidation of its molecular mechanisms might provide a rationale for new therapeutic strategies of malignant diseases.

Antineoplastic Agents↗
PubMed1998

[The diagnosis and treatment of primary carcinoma of the duodenum].

OBJECTIVE: To improve the diagnosis and treatment of primary duodenal carcinoma. METHOD: The records of 18 patients with primary carcinoma of the duodenum were reviewed. RESULT: 7 cases underwent pancreatoduodenectomy: segmental duodenectomy (1), intraoperative death (1), survived 3 years (2), and survived 5 years after operation (3). 7 cases underwent gastroenterostomy or cholangioenterostomy; they died in 11 months after operation. Three cases who received biopsy only died in six months after operation. CONCLUSION: The understanding of duodenal carcinoma is the key factor for early diagnosis. The appropriate examinations are necessary for suspected patients. Once the diagnosis is confirmed, the result of surgical treatment is improved.

Adult↗
PubMed1998

[Isolation and identification of Rhodopseudomonas acidophila from Fujian province, China].

A strain P301 of Gram negative purple nonsulfur bacterium was isolated from the ditch's mud collected in Fuzhou, Fujian. The cells are rod-shaped. Multiplication occur by budding without stalk formation. Growth optimum pH is 5.0-5.7. No growth factors required. The cells contain bacteriochlorophyll a. The photosynthetic membrane system consists of parallel lamellae. According to Bergery's Manual of Determinative Bacteriology, 8th ed. (1974) and 9th ed. (1994), the strain was identified to be Rhodopseudomonas acidophila. But on the side of enzyme activity, utilization of organic substrates and others the strain some differ from the type strain described by N Pfennig (1969). Therefore the strain P301 was identified to be Rhodopseudomonas acidophila var. fujianensis n. var.

China↗
PubMed1998

The dynamics of laser-induced changes in human skin autofluorescence--experimental measurements and theoretical modeling.

To study the temporal dynamics of human skin autofluorescence photobleaching, we measured the autofluorescence spectral changes of skin in vivo during continuous exposure to 442 nm (He-Cd) laser light. Integral intensities were calculated for various spectral wavelength bands and plotted as a function of time. Mathematical analysis of the time function revealed a double-exponential photobleaching process: I(t) = a exp (-t/tau 1) + b exp(-t/tau 2) + c, in which tau 1 and tau 2 differed by an order of magnitude. A hypothesis for the mechanism of the double-exponential photobleaching dynamics was proposed and evaluated using Monte Carlo modeling of light propagation in the skin and autofluorescence escape from skin. By combining the fluorophore microdistributions, Monte Carlo simulation results and the variation in fluorescence decrease parameters (a, b, c, tau 1, tau 2) with increasing exposure intensities a biophysical explanation for the double-exponential photobleaching function was elucidated. The fast decrease term corresponds to laser-induced photobleaching in the stratum corneum, while the slow decrease term represents fluorophore changes in the dermis. The measured autofluorescence photobleaching dynamics can be used to determine the fractional contributions of different skin layers to the total autofluorescence signal measured in vivo.

Fluorescence↗
PubMed1998

Molecular cloning of a chitinase gene from Bacillus circulans C-2.

The 2-10 kb DNA fragments of the PstI partially digested total DNA of Bacillus circulans C-2 were cloned into the PstI site of vector pUC19 and the resulting hybrid DNA molecules were then transformed into Escherichia coli. One chitinase gene-containing clone (named pCHT1) was selected from about 8000 recombinants on chitin overlay plates. Analysis of pCHT1 cut with 12 restriction enzymes showed that the inserted fragment in this clone was about 3.0 kb in size and contained one site for each of the three restriction enzymes: KpnI, SacI, and SspI. Cells harboring the recombinants plasmid (pCHT1-R) in which the insert was in an inverted orientation also displayed chitinase activity, indicating that the cloned fragment from B. circulans C-2 contained an intact chitinase gene and its own promoter could be recognized by the Escherichia coli transcriptional system. Southern hybridization analysis proved that the inserted fragment of pCHT1 was really from the genome of B. circulans C-2, and there was only one copy existing in the genome. This fragment could not hybridize with the total DNAs from the other seven chitinase-producing bacteria.

Bacillus↗
PubMed1997

Cloning and characterization of the murine homologue of the rat/human MRC OX-2 gene.

A 350 bp amplicon, obtained by PCR-select subtractive hybridization from RNA derived from mesenteric lymph nodes (MLN) cells from mice pre-immunized with allogeneic lymphocytes 36hrs prior to receiving donor-specific skin grafts, and showing > 98% homology with a published sequence for the rat MRC OX-2 gene, was used as a hybridization probe to screen a cDNA library constructed from adult mouse MLN treated in the same fashion. Several clones were identified which, on DNA sequence analysis, predicted a 218 amino acid protein showing significant homology with the rat and human MRC OX-2 gene product.

Adoptive Transfer↗
PubMed1997

Specificity for in vivo graft prolongation in gamma delta T cell receptor+ hybridomas derived from mice given portal vein donor-specific preimmunization and skin allografts.

gamma delta TCR+ hybridoma cells prepared from mesenteric lymph node cells of animals receiving donor-specific immunization via the portal vein can adoptively transfer this increased graft survival to naive animals. Analysis of TCR gamma-chain junctional sequence diversity suggested that some 40 to 50% of the hybridomas expressed gamma-chain junctional sequence diversity and were stimulated to produce cytokines both by heat shock proteins and by minor histocompatibility Ag-specific irradiated peritoneal cells. The remaining gamma delta TCR+ hybridoma cells expressed TCR with a common gamma-chain junctional sequence and were stimulated to cytokine production by MHC-matched, but minor histocompatibility Ag-mismatched (as well as matched), peritoneal cells, but not by heat shock proteins. We have compared the effectiveness of representative hybridomas expressing unique gamma-chain junctional sequences or common gamma-chain junctional sequences for prolongation of donor-specific or third-party (MHC-matched or MHC-mismatched) skin grafts. Our data show a good correlation between the specificity for stimulation for cytokine production in vitro and efficacy in graft prolongation assays in vivo. Hybridoma cells expressing unique gamma-chain junctional sequences that showed Ag-specific stimulation of cytokine production in vitro and skin graft survival in vivo augmented survival of third-party skin grafts if simultaneously transplanted with both Ag-specific and third-party skin grafts. Graft prolongation in vivo using cells from either population of gamma delta TCR+ hybridomas was decreased by infusion of anti-IL-10 mAb and abolished when both anti-IL-10 and anti-TGF-beta Abs were used together.

Adoptive Transfer↗
PubMed1997

Inhibition of protein synthesis in small cell lung cancer cells induced by the diphtheria toxin-related fusion protein DAB389 GRP.

DAB389 GRP is composed of the catalytic and transmembrane domains of diphtheria toxin fused to gastrin-releasing peptide (GRP). DAB389 GRP is selectively targeted to, and inhibits protein synthesis in, cell lines expressing GRP receptors. Protein synthesis in 5'ET4 cells (BALB/3T3 fibroblasts transfected with the gene encoding the GRP receptor) was inhibited by 50% in the presence of 20 pM DAB389 GRP (IC50, 20 pM). DAB389 GRP did not inhibit protein synthesis in untransfected BALB/3T3 cells. A second neuropeptide-conjugated toxin, DAB389 SP, directed to cells expressing substance P receptors, was not cytotoxic to 5'ET4 cells, nor was DAB389 GRP cytotoxic to substance P receptor-bearing cells. DAB389 GRP cytotoxic effects were receptor specific and were inhibited either by excess GRP or anti-GRP antibody. Cytotoxicity was mediated by passage through an acidic vesicle, because addition of 10 microM chloroquine to the reaction inhibited cytotoxicity. DAB389 GRP and DAB389 SP were tested on a number of tumor cell lines. DAB389 GRP inhibited protein synthesis in AR42J rat pancreatic acinar cells and HuTu 80 human duodenal adenocarcinoma cells with IC50s of 65 and 200 pM, respectively. DAB389 SP had an IC50 of 9.5 pM for the AR42J cells and 12 nM for the HuTu 80 cell line. A number of small cell lung cancer cell (SCLC) lines were tested, and the IC50 for DAB389 GRP ranged from 1.1 to 85 nM. Sensitivity to DAB389 GRP appeared to be based on receptor number and receptor type (i.e., GRP or neuromedin B preferring). SCLC cells were also sensitive to DAB389 SP, with IC50s ranging from 2.4 to 11.5 nM. These results suggest that a potential use exists for diphtheria-based fusion toxins as therapeutic agents for treatment of SCLC and other neuropeptide receptor-bearing cancers.

3T3 Cells↗
PubMed1997

Reconstruction of in vivo skin autofluorescence spectrum from microscopic properties by Monte Carlo simulation.

The in vivo skin autofluorescence spectrum was reconstructed by Monte Carlo simulation using microscopic fluorophore distributions and intrinsic fluorescence spectra measured from excised skin tissue sections as well as employing published skin tissue optical parameters. The theoretical modeling took into account the light-tissue interactions of scattering, absorption, and regeneration of fluorescence photons. The modification of the intrinsic spectra by tissue optical properties to generate the in vivo spectrum observed at the tissue surface can be represented by a fluorescence detection efficiency function (eta) which equals the integral of the product of the excitation light distribution inside the tissue and the fluorescence escape efficiency. Comparison of the reconstructed in vivo spectrum with the measured spectra showed good agreement, outside of the blood absorption bands, suggesting that (i) the theoretical modeling, (ii) the skin optical parameters used, and (iii) the measured microscopic morphology and spectral data are consistent. The divergence which exists over the strong blood absorption wavelength band (530-600 nm) suggests that the effect of blood contents on in vivo tissue optical properties deserves further investigations.

Computer Simulation↗
PubMed1997

[The technology of real time telemetring and monitoring multi-channels ECGs through public telephone network].

In this essay a kind of technology of real time telemetring and monitoring multi channels ECGs through public telephone network is presented. Two limb leaders (I and II) ECG signals are transmitted from the sender at first. After they are received by the receiver the other four limb leaders are calculated by computer in the basis of the relation among the limb leaders, the received waveform and the calculated waveform are just the same as those described directly by Electro Cardiograph. After the limb leaders ECG signals (34 s) are transmitted, two selectable thorax leaders ECG signals are transmitted for 34 seconds after automatically changing the leaders. The received ECG waves are displayed on screen real time, shifting smoothly. After transmission doctors may make diagnoses and give some suggestion for treatment. Thus, telemetrying and monitoring multi channels ECGs is realized.

Electrocardiography↗
PubMed1996

Effect of constant light and circadian entrainment of perS flies: evidence for light-mediated delay of the negative feedback loop in Drosophila.

Light is the dominant environmental cue that provides temporal information to circadian pacemakers. In Drosophila melanogaster some period gene mutants have altered free-running circadian periods but entrain to 24 h light-dark cycles. To address the mechanism of light entrainment in Drosophila, we examined the effects of constant light on the period gene (per) and timeless gene (tim) products in wild-type and perS flies. The results indicate that light affects three features of the PER-TIM program: PER and TIM phosphorylation, PER and TIM accumulation, and per and tim RNA cycling. A post-transcriptional effect on the PER-TIM complex is the likely primary clock target, which then delays the subsequent decrease in per and tim RNA levels. This is consistent with a negative feedback loop, in which the PER-TIM complex contributes to the decrease in per and tim RNA levels, presumably at the transcriptional level. There are enhanced constant light effects on the perS mutant, which further support negative feedback as well as support its importance to entrainment of these flies to a 24 h cycle, far from their intrinsic period of 19 h. The perS mutant leads to a truncated protein accumulation phase and a subsequent premature perS RNA increase. A standard 24 h light-dark cycle delays the negative feedback circuit and extends the RNA and protein profiles, compensating for the accelerated RNA increase and restoring the rhythms to wild-type-like periodicity.

Animals↗
PubMed1996

CD34+ human marrow cells that express low levels of Kit protein are enriched for long-term marrow-engrafting cells.

Using in utero transplantation into fetal sheep, we examined the capability of human bone marrow CD34+ cells fractionated based on Kit protein expression to provide long-term in vivo engraftment. Twelve hundred to 5,000 CD34+ Kit-, CD34+ Kit(low), and CD34+ Kit(high) cells were injected into a total of 14 preimmune fetal sheep recipients using the amniotic bubble technique. Six fetuses were killed in utero 1.5 months after bone marrow cell transplantation. Two fetuses receiving CD34+ Kit(low) cells showed signs of engraftment according to analysis of CD45+ cells in their bone marrow cells and karyotype studies of the colonies grown in methylcellulose culture. In contrast, two fetuses receiving CD34+ Kit(high) cells and two fetuses receiving CD34+ Kit- cells failed to show evidence of significant engraftment. Two fetuses were absorbed. A total of six fetuses receiving different cell populations were allowed to proceed to term, and the newborn sheep were serially examined for the presence of chimerism. Again, only the two sheep receiving CD34+ Kit(low) cells exhibited signs of engraftment upon serial examination. Earlier in studies of murine hematopoiesis, we have shown stage-specific changes in Kit expression by the progenitors. The studies of human cells reported here are in agreement with observations in mice, and indicate that human hematopoietic stem cells are enriched in the Kit(low) population.

Animals↗
PubMed1996

A light-entrainment mechanism for the Drosophila circadian clock.

Biochemical studies indicate that the Drosophila timeless protein (Tim) is a stoichiometric partner of the period protein (Per) in fly head extracts. A Per-Tim heterodimeric complex explains the reciprocal autoregulation of the proteins on transcription. The complex is under clock control, and many circadian features of the Tim cycle resemble those of the Per cycle. However, Tim is rapidly degraded in the early morning or in response to light, releasing Per from the complex. The Per-Tim complex is a functional unit of the Drosophila circadian clock, and Tim degradation may be the initial response of the clock to light.

Animals↗
PubMed1996

Experimental study on the early efficacy of excimer laser with adjunctive balloon angioplasty in dog's femoral artery.

The effect of domestically-manufactured excimer laser with adjunctive balloon angioplasty in achieving revascularization and reduction of residual stenosis was assessed. 20 femoral arteries with thrombosis and occlusion from 12 dogs were subject to angiography. At first excimer laser angioplasty was done followed by balloon angioplasty. The diameter and residual stenosis of revascularized vessel were measured. The result showed that 17 out of 20 vessels (85%) were revascularized. The diameter of revascularized vessel by excimer laser were 1.22 +/- 0.14 mm, while residual stenoses were 54% +/- 5%. After adjunctive balloon angioplasty the diameter and residual stenoses were 2.04 +/- 0.16 mm and 20% +/- 7% respectively (P < 0.05 and P < 0.01). Complication in form of vasoperforation occurred in 3/20 vessels (15%). It is concluded that China- manufactured excimer laser angioplasty is effective when used for revascularization. While the reduction of narrowing and residual stenoses was enhanced after adjunction of balloon angioplasty. This method can be employed in treating peripheral occlusive disease effectively and safely.

Angioplasty, Balloon, Laser-Assisted↗
PubMed1996

Proposed structure of putative glucose channel in GLUT1 facilitative glucose transporter.

A family of structurally related intrinsic membrane proteins (facilitative glucose transporters) catalyzes the movement of glucose across the plasma membrane of animal cells. Evidence indicates that these proteins show a common structural motif where approximately 50% of the mass is embedded in lipid bilayer (transmembrane domain) in 12 alpha-helices (transmembrane helices; TMHs) and accommodates a water-filled channel for substrate passage (glucose channel) whose tertiary structure is currently unknown. Using recent advances in protein structure prediction algorithms we proposed here two three-dimensional structural models for the transmembrane glucose channel of GLUT1 glucose transporter. Our models emphasize the physical dimension and water accessibility of the channel, loop lengths between TMHs, the macrodipole orientation in four-helix bundle motif, and helix packing energy. Our models predict that five TMHs, either TMHs 3, 4, 7, 8, 11 (Model 1) or TMHs 2, 5, 11, 8, 7 (Model 2), line the channel, and the remaining TMHs surround these channel-lining TMHs. We discuss how our models are compatible with the experimental data obtained with this protein, and how they can be used in designing new biochemical and molecular biological experiments in elucidation of the structural basis of this important protein function.

Amino Acid Sequence↗