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Biomedical subjects

Z Q Huang

Publications and source records attributed to Z Q Huang.

At least 19 recordsLinked to original sources
PubMed2001

Methylation of histone H4 at arginine 3 facilitating transcriptional activation by nuclear hormone receptor.

Acetylation of core histone tails plays a fundamental role in transcription regulation. In addition to acetylation, other posttranslational modifications, such as phosphorylation and methylation, occur in core histone tails. Here, we report the purification, molecular identification, and functional characterization of a histone H4-specific methyltransferase PRMT1, a protein arginine methyltransferase. PRMT1 specifically methylates arginine 3 (Arg 3) of H4 in vitro and in vivo. Methylation of Arg 3 by PRMT1 facilitates subsequent acetylation of H4 tails by p300. However, acetylation of H4 inhibits its methylation by PRMT1. Most important, a mutation in the S-adenosyl-l-methionine-binding site of PRMT1 substantially crippled its nuclear receptor coactivator activity. Our finding reveals Arg 3 of H4 as a novel methylation site by PRMT1 and indicates that Arg 3 methylation plays an important role in transcriptional regulation.

Acetylation↗
PubMed2001

Experimental research on TECA-I bioartificial liver support system to treat canines with acute liver failure.

AIM: To evaluate the efficacy and safety of the TECA-I bioartificial liver support system (BALSS) in treating canines with acute liver failure (ALF). METHODS: Ten canines with ALF induced by 80% liver resection received BALSS treatment (BALSS group). Blood was perfused through a hollow fiber tube containing 1X10(10) porcine hepatocytes. Four canines with ALF were treated with BALSS without porcine hepatocytes (control group), and five canines with ALF received drug treatment (drug group). Each treatment lasted 6 hours. RESULTS: BALSS treatment yielded beneficial effects for partial liver resection induced ALF canines with survival and decreased plasma ammonia, ALT, AST and BIL. There was an obvious decrease in PT level and increase in PA level, and there were no changes in the count of lymphocytes, immunoglobulins (IgA, IgG and IgM) and complement (C3 and C4) levels after BALSS treatment. In contrast, for the canines with ALF in non-hepatocyte BALSS group (control group) and drug group, there were no significant changes in ammonia, ALT, AST, BIL, PT and PA levels. ALF canines in BALSS group, control group and drug group lived respectively an average time of 108.0h +/- 12.0h, 24.0h +/- 6.0h and 20.4h +/- 6.4h,and three canines with ALF survived in BALSS group. CONCLUSION: TECA-I BALSS is efficacious and safe for ALF canines induced by partial liver resection.

Animals↗
PubMed2001

TECA hybrid artificial liver support system in treatment of acute liver failure.

AIM: To assess the efficacy and safety of TECA type hybrid artificial liver support system (TECA-HALSS) in providing liver function of detoxification, metabolism and physiology by treating the patients with acute liver failure (ALF). METHODS: The porcine liver cells (1-2) x 10(10) were separated from the Chinese small swine and cultured in the bioreactor of TECA-BALSS at 37.0 degrees C and circulated through the outer space of the hollow fiber tubes in BALSS. The six liver failure patients with various degree of hepatic coma were treated by TECA-HALSS and with conventional medicines. The venous plasma of the patients was separated by a plasma separator and treated by charcoal adsorbent or plasma exchange. The plasma circulated through the inner space of the hollow fiber tubes of BALSS and mixed with the patients' blood cells and flew back to their blood circulation. Some small molecular weight substances were exchanged between the plasma and porcine liver cells. Each treatment lasted 6.0-7.0 h. Physiological and biochemical parameters were measured before,during and after the treatment. RESULTS: The average of porcine liver cells was (1.0-3.0) x 10(10) obtained from each swine liver using our modified enzymatic digestion method. The survival rate of the cells was 85%-93% by trypan blue stain and AO/PI fluorescent stain. After cultured in TECA-BALSS bioreactor for 6 h, the survival rate of cells still remained 70%-85%. At the end of TECA-HALSS treatment, the levels of plasma NH(3), ALT, TB and DB were significantly decreased. The patients who were in the state of drowsiness or coma before the treatment improved their appetite significantly and regained consciousness, some patients resumed light physical work on a short period after the treatment. One to two days after the treatment, the ratio of PTA increased warkedly. During the treatment, the heart rates, blood pressure, respiration condition and serum electrolytes (K(+), Na(+) and Cl(-)) were stable without thrombosis and bleeding in all the six patients. CONCLUSION: TECA-HALSS treatment could be a rapid, safe and efficacious method to provide temporary liver support for patients with ALF.

Acute Disease↗
PubMed2001

[Determination of organophosphorus pesticide multi-residues in tea by gas chromatography].

An efficient gas chromatographic method for the determination of 14 organophosphorus pesticide residues in tea by gas chromatography using micro-chemical and solid phase extraction technique has been established. The organophosphorus pesticides were extracted from tea samples with ethyl acetate and mixture of ethyl acetate-hexane(1:1, V/V). The extracts were cleaned up with a column of 3 mL Supelclean Envl-carb by GILSON ASPEC XL. The 14 organophosphorus pesticides were separated from each other through SPB-1701 capillary column(30 m x 0.53 mm i.d. x 1.0 micron) and determined by flame photometric detector. The recoveries ranged 70.8%-120% when the added levels were from 0.100 mg/kg to 1.00 mg/kg, the RSD was 2%-7% and the limits of detection were 0.01 mg/kg-0.08 mg/kg. This method is rapid, sensitive and suitable for the analysis of pesticide residues. It can also be applied to the determination of organophosphorus pesticide multi-residues in other plant samples such as vegetables, fruits and so on.

Chromatography, Gas↗
PubMed2000

Apoptosis induced by 5-flucytosine in human pancreatic cancer cells genetically modified to express cytosine deaminase.

AIM: To elucidate the pattern of 5-flucytosine (5-FC)-induced apoptosis and its role in gene therapy of human pancreatic cancer. METHODS: The human pancreatic cancer SW1990 cells (CEA-producing) were infected with recombinant adenoviruses (Adex1CEA-prCD or Adex1CEA-prZ). Expression of CD gene protein was examined by western blot. Apoptosis induced by 5-FC in human pancreatic cancer SW1990 cells genetically modified to express cytosine deaminase was observed by means of electron microscopy, DNA electrophoresis, and flow cytometry analysis techniques. RESULTS: The SW1990 cells infected with Adex1CEA-prCD were treated with 5-FC at 100 mumol.L-1 for 48 h, and cell apoptosis was observed. Typical apoptosis morphological feature appeared and DNA ladder could be demonstrated on DNA electrophoresis. Apoptosis peak was also showed by flow cytometry. Apoptotic cells accounted for 34.6% of the cell population. Cells in G1, S, and G2/M phase of cell cycle were 64%, 11%, and 7%, respectively. CONCLUSION: The apoptosis induced by 5-FC may be a primary mechanism in CD gene therapy of pancreatic cancer.

Adenoviruses, Human↗
PubMed1997

Preclinical studies of allograft tolerance in rhesus monkeys: a novel anti-CD3-immunotoxin given peritransplant with donor bone marrow induces operational tolerance to kidney allografts.

A major challenge in clinical transplantation today is to design a practical and effective protocol for tolerance induction compatible with cadaver organ transplantation. A preclinical rhesus monkey kidney allograft model using immediate peritransplant anti-CD3 immunotoxin (anti-CD3-IT) and donor bone marrow (DBM) is shown here to induce operational tolerance with prolonged graft survival in the absence of chronic immunosuppressive drugs. Bone marrow harvested from the kidney donor was depleted of mature alloantigen-presenting cells and T cells by removing DR(bright) cells and CD3(bright) cells, respectively. In outbred, major histocompatibility complex-incompatible donor-recipient pairs with high pretransplant mixed lymphocyte response and cytotoxic T lymphocyte precursor activity, four of six allografts survived for periods of 120 days to >1.5 years. Graft acceptance after peritransplant treatment followed robust elimination of both peripheral blood T cells and lymph node T cells. In most recipients given anti-CD3-IT and DBM infusion, anti-donor immunoglobulin G responses were completely inhibited. Microchimerism was observed in all recipients studied, including those not given DBM, but levels of microchimerism did not correlate with graft survival. Anti-CD3-IT induction in combination with modified DBM protocols such as the depletion of mature T cells and DR(bright) antigen-presenting cells may offer new opportunities to improve clinical tolerance protocols beyond those attempted in the clinic to date. Overall, these results with anti-CD3-IT show promise for development of cadaver transplant tolerance induction.

Animals↗
PubMed1997

Localization of a single binding site for immunoglobulin light chains on human Tamm-Horsfall glycoprotein.

Cast nephropathy is a severe complication of multiple myeloma. Binding of filtered monoclonal light chains (LC) with Tamm-Horsfall glycoprotein (THP) triggers heterotypic aggregation of these two proteins to form casts in the distal nephron of the kidney. To localize the LC binding site on THP, human THP was deglycosylated and underwent limited trypsin digestion in the presence or absence of a nephrotoxic LC known to bind THP. A 29.6-kD band was protected from trypsin digestion by the addition of LC. NH2-terminal amino acid sequence and amino acid analyses revealed this band was located between the 6th and 287th amino acid residues of THP. Six peptides located within this 29.6-kD fragment were synthesized and used as potential inhibitors of binding or aggregation of five different nephrotoxic LCs with THP. Peptide AHWSGHCCL (from amino acid 225 to 233) completely inhibited binding and aggregation of these proteins. Optimal inhibition required a cystine residue in this peptide. Truncation experiments demonstrated the entire sequence was necessary for ideal inhibition and the histidine residue explained the effects of pH on binding. These studies provided a basis for further study of LC-THP interaction and a potential approach toward the prevention of cast nephropathy.

Binding Sites, Antibody↗
PubMed1996

[Effect of hemin in treating hemorrhagic anemia and toxicity].

AIM: To study the effect of hemin in treating hemorrhagic anemia and toxicity. METHODS: Fifty rats with hemorrhagic anemia were randomly divided into 5 groups with different dosage of hemin (93, 168, 300 mg.kg-1.d-1), ferrous gluconate (FG 300 mg.kg-1.d-1), and water, ig for 7 d. Twenty mice fed with hemin (6.0 g.kg-1.d-1) in 24 h for observing acute toxicity effects. Long-term toxicity were observed in 80 rats given hemin (0.65, 1.3, 2.6 g.kg-1.d-1) in 3 months. RESULTS: Hb of the rats of corresponding groups were 66-->121, 71-->141, 66-->148, 69-->140, and 67-->112 g.L-1. There were no adverse effects observed on acute toxicity test. No abnormalitis were found in hemogram, liver renal function test, and autopsy. CONCLUSION: Hemin had a better effect than FG and no adverse effect was found in hemin.

Anemia, Iron-Deficiency↗
PubMed1995

[Effect of Astragalus membranaceus on T-lymphocyte subsets in patients with viral myocarditis].

The efficacy of Astragalus membranaceus (AM) oral liquor combined with routine therapy and routine therapy alone on T-lymphocyte subsets of peripheral blood in viral myocarditis patients have been studied. The results showed that the T-lymphocyte subsets profile and OKT4/OKT8 ratio of peripheral blood were significantly lower in viral myocarditis patients than that in healthy control (P < 0.05, 0.01). Routine therapy combined with AM could significantly enhance OKT3, OKT4 and OKT4/OKT8 ratio in the above-mentioned patients (P < 0.05, 0.01). The possible pharmacodynamic mechanism of improved cell immunity in viral myocarditis patients by combining routine therapy with AM was discussed.

Adolescent↗
PubMed1995

Pathogenesis of glomerulosclerosis in light chain deposition disease. Role for transforming growth factor-beta.

The glomerulopathy of monoclonal immunoglobulin light chain deposition disease is a progressive disorder characterized by accumulation of monoclonal light chains and matrix proteins in the mesangium. To define the role of light chains in this process, cultured rat mesangial cells were exposed to different light chains and human albumin. Two light chains were purified from the urine of patients who had biopsy-proven light chain deposition disease. These proteins inhibited mesangial cell proliferation and increased production of matrix proteins, including type IV collagen, laminin, and fibronectin. By immunocytochemistry and bioassay, transforming growth factor-beta (TGF-beta) production and activity increased when mesangial cells were exposed to these proteins. Furthermore, anti-TGF-beta antibody abolished the inhibition of cell proliferation and the increase of extracellular matrix protein production caused by these light chains. These findings were not observed in mesangial cells exposed to human albumin and two other light chains previously characterized to be tubulopathic. We concluded that the glomerulopathic light chains increased TGF-beta, which inhibited mesangial cell proliferation and increased matrix protein production. Together with overexpression of TGF-beta in affected glomeruli of light chain deposition disease, light chain-mediated stimulation of mesangial cells to produce TGF-beta appears to be a key pathological mechanism of this disease.

Animals↗
PubMed1995

Biochemical interaction between Tamm-Horsfall glycoprotein and Ig light chains in the pathogenesis of cast nephropathy.

BACKGROUND: Cast nephropathy in multiple myeloma patients is caused by heterotypic aggregation of Tamm-Horsfall glycoprotein (THP) with monoclonal light chains (Bence Jones protein, BJP). Co-aggregation of these proteins is triggered by the binding of BJP to a specific peptide portion of THP. Defining those factors that alter the interaction between BJP and THP may help to understand further the pathogenesis of cast nephropathy and serve to decrease the morbidity and mortality of cast nephropathy. We hypothesized that pH, calcium, furosemide, and the carbohydrate moiety of THP all modulate the protein-protein interaction between BJP and THP. EXPERIMENTAL DESIGN: Binding affinity and aggregation rate of human THP with two human nephrotoxic BJP were tested at pH 8.5, 7.4, and 5.0. The effects of calcium, furosemide, and free sialic acid were also evaluated. Binding and aggregation of BJP with THP purified from normal volunteers treated with oral colchicine were observed. The carbohydrate components of THP were also analyzed. RESULTS: An acidic environment increased initial binding rate and produced a parallel increase in the aggregation rate of THP with BJP. Calcium and furosemide enhanced aggregation rates without interfering with binding. Colchicine treatment decreased the amount of sialic acid linked alpha(2-6) to galactose (NeuAc alpha 2-6Gal) and sialic acid linked alpha(2-3) to galactose (NeuAc alpha 2-3Gal) on THP and thereby decreased the aggregation rate with BJP without altering binding. Addition of free sialic acid did not alter binding but did decrease aggregation rates of the two proteins. CONCLUSIONS: Environmental conditions modulate BJP-THP interactions and may be responsible for inducing case nephropathy in multiple myeloma. Modification of carbohydrate components of THP or use of oligosaccharides may decrease or prevent cast nephropathy.

Colchicine↗
PubMed1994

[Antitumor activity of thevetoside alone and in combination with chlormethine in vivo].

Thevetoside (TS) is one of the cardiac glycosides. A study of antitumor activity was carried out in 6 types of murine tumors in vivo, such as the ascitic tumors H22, EAC, P388, and solid tumors S180, U14, Lewis lung carcinoma, which were treated with i.p. TS 1.5 mg.kg-1.d-1 alone or in combination with chlormethine (Chl) 0.3, 0.5, or 1.0 mg.kg-1.d-1. TS only showed a remarkable inhibition on the growth of 3 types of solid tumors with inhibition rates of 48.7%-56.7%. The effect of the combination therapy was much pronounced than that of independent administration. The life span under combined therapy was increased 82.4% to > 122.1%. For solid tumors, the combined administration gave inhibition rates of 65.6%-72.5%.

Animals↗
PubMed1994

[Effects of selective hepatic duct embolization on normal, cirrhotic livers and hepatocellular carcinomas].

Variant gross and pathology features were observed on effects of selective hepatic duct embolization (SHDE) in contrast to selective hepatic duct ligation (SHDL). Glue TH was used in SHDE that performed on normal liver, induced cirrhotic liver and hepatocellular, carcinoma. The results demonstrated that SHDL has weak effected, while SHDE causes the embolized liver lobes to acute ischemic necrosis, followed by atrophy and fibrosis, accompanied by quickly hypertrophy of the uninvolved lobes. All tumors on the embolized liver lobes also showed acute tumors on the embolized liver lobes also showed acute tumor ischemic necrosis, atrophy and fibrosis. The reason for the above variations is that pressure and tension of SHDE expand the embolized bile duct tree, especially the Hering duct, which will continuously obstruct the dual blood supply to the liver tumor. Effectively and thoroughly annihilating or restricting the tumor, SHDE may lead the tumors to "spontaneous excision", with the unoperated lobes hypertrophy to compensate liver functions simultaneously. These studies indicated that SHDE will be a new method in liver cancer clinic.

Animals↗
PubMed1993

Bence Jones proteins bind to a common peptide segment of Tamm-Horsfall glycoprotein to promote heterotypic aggregation.

Bence Jones proteins (BJPs) are the major pathogenic factor causing cast nephropathy ("myeloma kidney") by coaggregation with Tamm-Horsfall glycoprotein (THP). Understanding the interaction between these proteins is therefore important in developing treatment strategies to prevent renal failure from cast formation in multiple myeloma. We developed an enzyme-linked immunoassay to examine this phenomenon. Five different human BJPs (four kappa and one lambda immunoglobulin light chains) were used in this assay that demonstrated these proteins bound THP with different affinity. BJPs competed among themselves for binding to THP. The binding site was a peptide portion of THP since these proteins also bound deglycosylated THP. Also, one monoclonal antibody directed against a peptide segment of human THP prevented binding of THP to BJPs. By altering the conformation of THP, reducing agents decreased binding between these two proteins in concentration-dependent fashion. In turbidity studies, the monoclonal antibody that prevented binding and a reducing agent, dithiothreitol, decreased coaggregation. Deglycosylated THP did not coaggregate with BJPs. We concluded that ionic interaction between BJPs and a specific peptide binding site on THP promoted heterotypic coaggregation. The carbohydrate moiety of THP was also essential for coaggregation, perhaps by facilitating homotypic aggregation of THP.

Bence Jones Protein↗
PubMed1992

Parallel stranded DNA under the scanning tunnelling microscope.

Using scanning tunnelling microscopy, we have directly observed parallel stranded DNA helixes of 43 nucleotides in length. The double helix is right-handed and has an average spacing, 17.43 A (+/- 1 S.D.: 2.30 A), and an average apparent depth, 4.79 A (+/- 1 S.D.: 1.04 A) for each groove. The average pitch of the helical turn is 34 A (+/- 1 S.D.: 3.35 A) and consists of no more than ten base pairs. The diameter of the helix is approx. 17-20 A. Our results provide direct evidence for the existence of a parallel structure of DNA in vitro and some details of its fine structure.

Base Sequence↗