Search PubMed⌕ Search

Biomedical subjects

Z He

Publications and source records attributed to Z He.

At least 73 records · Page 4Linked to original sources
PubMed2000

Reactions involved in the lower pathway for degradation of 4-nitrotoluene by Mycobacterium strain HL 4-NT-1.

In spite of the variety of initial reactions, the aerobic biodegradation of aromatic compounds generally yields dihydroxy intermediates for ring cleavage. Recent investigation of the degradation of nitroaromatic compounds revealed that some nitroaromatic compounds are initially converted to 2-aminophenol rather than dihydroxy intermediates by a number of microorganisms. The complete pathway for the metabolism of 2-aminophenol during the degradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 has been elucidated previously. The pathway is parallel to the catechol extradiol ring cleavage pathway, except that 2-aminophenol is the ring cleavage substrate. Here we report the elucidation of the pathway of 2-amino-4-methylphenol (6-amino-m-cresol) metabolism during the degradation of 4-nitrotoluene by Mycobacterium strain HL 4-NT-1 and the comparison of the substrate specificities of the relevant enzymes in strains JS45 and HL 4-NT-1. The results indicate that the 2-aminophenol ring cleavage pathway in strain JS45 is not unique but is representative of the pathways of metabolism of other o-aminophenolic compounds.

Amino Acids↗
PubMed2000

Interaction of PIP(2) with the XIP region of the cardiac Na/Ca exchanger.

The sarcolemmal Na/Ca exchanger undergoes an inactivation process in which exchange activity decays over several seconds following activation by the application of Na to the intracellular surface of the protein. Inactivation is eliminated by an increase in membrane phosphatidylinositol 4,5-bisphosphate (PIP(2)). Inactivation is also strongly affected by mutations to a basic 20-amino acid segment of the exchanger known as the endogenous XIP region. The hypothesis that PIP(2) directly interacts with the XIP region of the exchanger was tested. First, we investigated the ability of a peptide with the same sequence as the XIP region to bind to immobilized phospholipid vesicles. (125)I-labeled XIP bound avidly to vesicles containing only a low concentration (<3%) of PIP(2). The binding was specific, in that binding was not displaced by other basic peptides. The effects of altering the sequence of XIP peptides also indicated binding specificity. Second, we examined the functional response to PIP(2) of exchangers with mutated XIP regions. Outward Na/Ca exchange currents were measured using the giant excised patch technique. The mutated exchangers either had no inactivation or accelerated inactivation. In both cases, the exchangers no longer responded to PIP(2) or to PIP(2) antibodies. Overall, the data indicate that the affinity of the endogenous XIP region for PIP(2) is an important determinant of the inactivation process.

Animals↗
PubMed2000

Cellular localization of gene expression for progranulin.

Granulins, also called epithelins, are 6-kD peptides with growth modulatory effects on a variety of cells. The granulin/epithelin precursor supports tumorigenesis in appropriate cell models and is the only growth factor able to overcome the cell cycle block that occurs in murine fibroblasts after deletion of a functional IGF-1 receptor. However, little is known of the role of granulin/epithelin gene products in vivo. To understand the physiological role of granulins it is essential to know the cell types and conditions in which it is expressed. We examined granulin/epithelin gene expression in adult rodents by in situ hybridization. The granulin/epithelin precursor is constitutively expressed in a number of epithelia, particularly in the skin, GI tract, and reproductive system. Other epithelia express the gene less strongly. Progranulin is expressed in immune cells in vivo and in specific neurons in the brain, including Purkinje cells, pyramidal cells of the hippocampus, and some cerebral cortical neurons. Little expression was detected in muscle cell, connective tissue, or endothelium. Cumulatively, these results define the basal gene expression of a new growth factor system and suggest that the progranulin/epithelin gene is multifunctional, with important constitutive roles in epithelial homeostasis, reproductive, immunological, and neuronal function.

Animals↗
PubMed2000

Blood plasma chemistries from wild mourning doves held in captivity.

Despite the extensive amount of research conducted on mourning doves (Zenaida macroura), no biochemical reference values exist for this species. Our objective, therefore, was to establish base line clinical chemistry reference values for mourning doves to assist with establishing clinical diagnoses. Wild mourning doves were captured 19 March 1996 to 8 August 1996, and 6 February 1998 to 12 May 1998; blood samples were collected from 382 mourning doves. Plasma biochemical values were established for glucose, sodium, potassium, chloride, enzymatic CO2, albumin, total protein, globulin, calcium, phosphorus, cholesterol, magnesium, aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), lactate dehydrogenase (LDH), and uric acid. These reference values are invaluable for determining diagnosis of diseases of the gastrointestinal, hepatic, renal, cardiovascular, musculoskeletal, and endocrine systems.

Animals↗
PubMed2000

[Induction of apoptosis in human hepatocellular carcinoma cells by adenoviral-mediated transfer of human multigenes].

OBJECTIVE: To investigate the apoptosis induced by adenovirus-mediated transduction of human genes (p53, B(7-1), GM-GSF, IL-2) in liver cancer cells and the effects of tumorigenicity in nude mice. METHODS: Using light microscopy and electron microscopy and TUNEL assay, apoptosis in Ad-multigenes-transduced liver cancer cell lines was detected. The tumorigenicity of HepG(2) cells transduced with Ad-multigenes was detected. RESULTS: Ad-multigenes could induce apoptosis, and elevated sensitivity of human liver cancer cells to chemotherapy drugs. After cells with transduced Ad-multigenes were treated with 10mg/L cisplatin for 24 h, apoptosis was seen in nearly 30% of them. The tumorigenicity of Ad-multigenes-transduced was reduced. CONCLUSION: Apoptosis induced by adenovirus-mediated multigenes acts synergetically with cisplatin in promotion of inducing apoptosis in liver cancer cell lines.

Adenoviridae↗
PubMed2000

Acute vaginal candidosis model in the immunocompromized rat to evaluate delivery systems for antimycotics.

A rat model of vaginal candidosis, suitable for screening new antifungal compounds or novel formulations was developed and validated. Two strains of Candida albicans, different inoculation schedules, quantitative assays for fungal burden and the necessity for immunosuppression were tested. The infection was evaluated clinically and histologically by fungal counts from the vaginal discharge. The animals without immunosuppression did not sustain the infection beyond 2-3 days, however, after immunosuppression with cyclophosphamide, the infection can be maintained for about 2 weeks and is suitable for the testing of topical antifungal therapies.

Acute Disease↗
PubMed2000

An insight into the assembly and organization of photosystem I complex in the thylakoid membranes of the thermophilic cyanobacterium, Mastigocladus laminosus.

The present study characterizes the assembly and organization of Photosystem I (PSI) complex, and its individual subunits into the thylakoid membranes of the thermophilic cyanobacterium, Mastigocladus laminosus. PSI is a multiprotein complex that contains peripheral as well as integral subunits. Hence, it serves as a suitable model system for understanding the formation and organization of membrane protein complexes. In the present study, two peripheral cytosol facing subunits of PSI, namely, PsaD and PsaE were overexpressed in E. coli and used for assembly studies. The gene encoding PsaK, an integral membrane spanning subunit of PSI, was cloned and the deduced amino acid sequence revealed PsaK to have two transmembrane alpha-helices. The characterization of the in vitro assembly of the peripheral subunits, PsaD and PsaE, as well as of the integral subunit, PsaK, was performed by incubating each subunit with thylakoids isolated from Mastigocladus laminosus. All three subunits studied were found to assemble into the thylakoids in a spontaneous mechanism, showing no requirement for cytosolic factors or NTP's (nucleotide 5'-triphosphate). Nevertheless, further characterization of the assembly of PsaK revealed its membrane integration to be most efficient at 55 degrees C. The associations and protein-protein interactions between different subunits within the assembled PSI complex were directly quantified by measurements performed using the BIACORE technology. The preliminary results indicated the existence of specific interaction between PsaD and PsaE, and revealed a very high binding affinity between PsaD and the PSI electron acceptor ferridoxin (Kd = 5.8 x 10(-11) M). PsaE has exhibited a much lower binding affinity for ferridoxin (Kd = 3.1 x 10(-5) M), thereby supporting the possibility of PsaE being one of the subunits responsible for the dissociation of ferridoxin from the PSI complex.

Amino Acid Sequence↗
PubMed2000

[Detection for anti-Hantavirus IgM in patient serum with silver enhanced dot immunogold filtration assay].

OBJECTIVE: To establish a more rapid and simple method for detecting anti-Hantavirus IgM in patient' s serum. METHODS: A silver enhanced dot immunogold filtration assay (SEDIGFA) was developed by coating the nucleocapsid protein of Hantavirus on nitrocellulose (NC) membrane, adding colloidal gold labeled sheep anti-human IgM antibody and the silver enhancer. The whole procedure can be finished within 10 minutes. RESULTS: The coincidence rate of the results of serum samples simultaneously operated with ELISA and SEDEIGFA was 98% for anti-Hantavirus IgM. CONCLUSIONS: SEDIGFA is more simple and rapid for application to small medical laboratories. It can be applied for early diagnosis of hemorrhagic fever with renal syndrome (HFRS).

Gold Colloid↗
PubMed2000

[Cloning and sequencing of complete TT virus genome from Beijing isolate of China].

OBJECTIVE: To obtain the complete TT virus genome from a Beijing isolate of China. METHODS: PCR was performed for amplifying the TT virus genome from serum of a patient with non A-G hepatitis. Five overlapped fragments, that are 199 bp (1-199), 1 267 bp (90-1356), 878 bp (1354-2231),1129 bp(2178-3306),'434 bp(3306-3739), respectively, were obtained. These PCR products were sequenced by standard method. RESULTS: The complete TT virus genome of Beijing isolate consists of 3 739 nucleotides involving two ORFs. The first ORF locates at 589-2902 nt, encoding 770 amino acids, the second ORF locates at 107-715 nt, encoding 202 amino acids. 5' and 3' terminus of the genome are non-coding regions including 106 bp and 837 bp respectively. In this genome, A is 31.2%, C 25.4%, G 22.5% and T 20.9%. The homology of Beijing isolate and Japanese TT virus was more than 95% at both nucleotide and amino acid levels. CONCLUSIONS: We successfully cloned and sequenced the complete TT virus genome from a Chinese patient. This Beijing TT virus isolate and that reported by Japan all belong to a same genotype.

Amino Acid Sequence↗
PubMed2000

[Exploration of the mechanism of skin expansion].

OBJECTIVE: In order to explore the mechanism of skin expansion technique (SET). METHODS: Domestic dogs were used in this experiment. The epidermal mitotic activity, capillary blood flow change of the expanded flap were observed with microspectrophotometer and radioactive microsphere technique. RESULTS: 1. The epidermis of expanded skin was significantly thicker than that of other groups (P < 0.05). 2. The epidermal mitotic activity was elevated significantly(P < 0.01). 3. The capillary blood flow of expanded flaps increased significantly (P < 0.01). CONCLUSIONS: 1. The surplus skin produced by SET is the result of replication, not compensation. 2. SET increases skin blood flow, therefore enlarges the survival area of an expanded flap.

Animals↗
PubMed2000

[The diagnosis and treatment of microgenia].

OBJECTIVE: This article is to elucidate the indications of horizontal advancement osteotomy of the mandible or bone grafting for microgenia. METHODS: After understanding the characteristics of a patient's inferior one-third facial malformation through physical and cephalometric measurement, we correct the malformation of moderate or serious degree with osteotomy genioplasty. RESULTS: Eight patients received the operation and obtained good results. CONCLUSION: Understanding the characteristics of microgenia and choosing a rational method is the prerequisite for a good operative result.

Adult↗
PubMed2000

[Modulating effect of vitamin D3 in vitro on EGFR mRNA expression of human breast cancer cell lines].

OBJECTIVE: To assess the modulating effects of vitamin D3, combined with or without tamoxifen, on cell proliferation and EGFR mRNA level of human breast cancer. METHODS: Two breast cancer cell lines (MCF-7 and ZR-75-1) were treated with various concentrations of vitamin D3, alone or in combination with tamoxifen, for 6 days. Cell proliferation was assessed by MIT uptake and EGFR mRNA level by Northern blot. RESULTS: 10(-10)-10(-7) mol/L vitamin D3 strongly inhibited proliferation of the 2 breast cancer lines, while 10(-9)-10(-7) mol/L tamoxifen stimulated proliferation of MCF-7 cell. The growth inhibitory effect on the 2 cell lines could be augmented and accompanied by a decrease in EGFR mRNA level after combined treatment with IC50 dose of tamoxifen and 10(-10)-10(-9) mol/L vitamin D3. CONCLUSION: Vitamin D3 can be considered as a useful anti-tumor drug in the treatment of breast cancer.

Antineoplastic Agents, Hormonal↗
PubMed2000

[Laboratory study on protective and therapeutic effects of pinacidil on pulmonary vascular remodeling in rats with hypoxia-induced pulmonary hypertension].

OBJECTIVE: To investigate the protective and therapeutic effects of pinacidil on hypoxia-induced pulmonary hypertension(HPH) and pulmonary vascular remodeling. METHODS: 46 male Wister rats were divided into control group, hypoxic group and treated group (hypoxic rat treated with pinacidil for 4 weeks). Rat models with chronic HPH were established by chronic hypobaric hypoxia [(10 +/- 0.5)% O2, 4 weeks)]. The mean pulmonary arterial pressure (mPAP) and right ventricle/left ventricle and septum [RV/(LV + S)] were measured and the small pulmonary arterial morphologic changes were observed with morphmetric analysis under microscopes in three groups. RESULTS: (1) The level of mPAP(28.4 +/- 2.8) mm Hg and RV/(LV + S) (0.30 +/- 0.03) were significantly higher in the hypoxic group than (16.2 +/- 1.8) mm Hg and (0.22 +/- 0.03) in control group respectively (P < 0.01). Morphometry investigation showed that the external diameter became smaller and that ratio of vascular wall thickness to external diameter (MT%) (25.7 +/- 2.6)% and ratio of vascular wall area to total area (MA%) (75.3 +/- 5.6)% significantly increased in the hypoxic group. (2) The mPAP(23.3 +/- 2.6) mm Hg, RV/(LV + S) (0.27 +/- 0.04) and pulmonary vascular pathologic changes MT%(22.1 +/- 2.5)% and MA% (67.0 +/- 6.1)% significantly decreased in the treated group, indicating that pinacidil inhibited HPH and hypoxia-induced thickening and muscularization of small pulmonary arteria. CONCLUSION: Pinacidil may partly prevent the development of HPH and pulmonary vascular remodeling.

Animals↗
PubMed2000

[Cloning and sequencing of a Chinese complete TTV gene].

OBJECTIVE: To obtain the complete TT virus gene from a Chinese isolate. METHODS: Long-PCR was performed for amplifying the TTV gene from the serum of a Chinese with non-A to non-G hepatitis. Three overlapped DNA fragments were obtained, which contained 199 bp (1-199), 3 269 bp (38 approximately 3 306) and 434 bp (3 306 approximately 3 739) separately. These PCR products were sequenced by the standard method. RESULTS: The complete TTV gene (named as TTV CHN1) consisting of 3 739 nucleotides contained two ORFs. The first ORF located at 589 approximately 2 901 nt, coding 770 amino acids; the second located at 107 approximately 715 nt, coding 202 amino acids. In this genome, G is 22.25%, C 25.54%, A 31.26% and T 20.97%. The homology of Chinese and Japanese TTV genes was more than 94% at both nucleotide and amino acid levels. There exists a hyper-variation region (HVR) spanning at 1 380 approximately 1 800 bp. In this region, the HVR homology of Chinese and Japanese TTV genes was 88% and 81% at nucleotide and amino acid levels, respectively. CONCLUSION: Chinese and Japanese TTV isolates belong to the same genotype. There exists a hyper-variation region (HVR) spanning at 1 380 approximately 1 800 bp.

Amino Acid Sequence↗
PubMed2000

[Presence and replication of TTV DNA in peripheral blood mononuclear cells from hepatitis patients with TTV infection].

OBJECTIVE: To study the presence and replication of TTV DNA in the peripheral blood mononuclear cells (PBMC) from hepatitis patients with TTV infection. METHODS: Nested-PCR (nPCR) was performed for detecting the TTV DNA from the sera, PBMCs and feces of 16 patients with non-A to non-G hepatitis in Beijing Ditan Hospital from Oct. 1997 to Oct. 1998. PBMC DNAs were aslo digested by mung bean nuclease and amplified by nPCR to clasify if TTV DNA was still positive. nPCR products of the sera, PBMCs and feces of 5 hepatitis patients with non-A to non-G hepatitis were cloned and sequenced. RESULTS: 14 of the 16 samples of PBMC and 5 of the 16 samples of the feces were TTV DNA positive. Two of the 14 samples of the PBMC were still positive after the digestion and amplification of the single-stand DNA. Sequence analysis showed that there was more than 95% nucleotide homology among the sequenced 5 clones (from the sera, PBMC and feces of the 5 patients) and reported AB008394 (from Japan) and AF079173 (from China). Virus loading of patients whose feces were positive by nPCR was obviously more than the patients with negative TTV DNA. CONCLUSION: TTV DNA can exist and replicate in the PBMC; the hepatocytes of patients with TTV infection are not the only place of TTV existence and replication.

Adult↗