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Biomedical subjects

H C Zhu

Publications and source records attributed to H C Zhu.

11 recordsLinked to original sources
PubMed2001

[In vitro culture of modified neonatal pig islets].

A cell-isolation-and-cell-culture-in-vitro method which can produce a mass of new-born pig islet-like clusters was introduced. The new-born pig pancreas were incubated in V-type collagenase (0.5-1.0 mg.ml-1) for 8-12 minutes, and then cultured in vitro for 7 days before large amount of highly purified porcine islets were produced. The neonatal pig islets had good insulin secretion and normal sub-cell structure. The results suggest that the neonatal pig islets are probably a fine donor source for clinical xenotransplantation of islets.

Animals↗
PubMed2001

[High cell density culture of phosphotransacetylase mutants of Escherichia coli BL21(DE3)].

Cell culture, organic acid production and foreign protein (TNF) expression of E. coli BL21(DE3) and its pta mutant were investigated. Under shaking conditions, TNF expression in pta mutant increased by 23%. During the fed-batch culture without limitation of specific growth rates, the mutant reached a cell density as high as 32.5 g(DCW)/L and total TNF expression at 2.8 g/L, while the parental strain only obtained 19.5 g(DCW)/L and 0.84 g/L. The results indicate that utility of pta mutant as a host is advantageous in foreign protein expression and high cell density culture. Meanwhile, the analysis data of organic acids accumulated during fed-batch culture showed that as the decrease of acetate production(42% of the parental strain), the accumulation of other organic acids(mainly pyruvate, lactate and succinate) obviously increased. As a result, the amount of total organic acids increased by 123% over its parent. The lactate production may be the main obstacle in further growth of the cells.

Acetates↗
PubMed2001

[Studies on bioconversion conditions and stereoselectivity of Arthrobacter K1108 hydantoinase].

The bioconversion conditions of hydantoinase of Arthrobacter K1108 were studied. It was shown that the optimum temperature of the enzyme is 55 degrees C, and the optimum pH is 7.0. The enzyme can be activated by Co2+ and Fe2+, while inhibited by Ca2+. The optimal substrate of the hydantoinase is 5-benzylhydantoin, while 5-phenylhydantoin and 5-indolylmethylhydantoin cannot effectively digested, showing a high specificity on the substrates. An investigation on the hydantoinase stereoselectivity mechanism showed that the N-carbamoylamino acid hydrolase is stereoselective but the hydantoin hydrolase is not.

Amidohydrolases↗
PubMed2000

[Characteristics of an established cervical carcinoma cell line HCE1].

This paper deals with a new cell line established from 5 carcinoma specimens of hysterectomy and designated as HCE1. This cell line has been passaged more than 80 times(more than 18 months). It has the characteristics: 1. The pathological features of the tumor transplanted in nude mice were similar to that of the original inoculated lesion; 2. Electromicroscopically, there were rich microvilli on the surface of the cells. Abundant ribosomes were also observed; 3. The growth curves of the 25th passage were determined, the population doubline time calculated in the log phase of growth was 45.8 h; 4. The cloning efficiency in soft agar averaged 14.8% after counting 6 plates; 5. Karyo-type analysis showed aneuploidy with the modal chromosomal number 64-97.

Animals↗
PubMed1998

Geological controls to the indoor radon distribution in southern Belgium.

Soils and rocks are the predominant source of indoor radon (Rn) in southern Belgium. We have studied the correlations between geological features and indoor Rn concentrations using an indoor Rn data set of approx. 1700 short-term measurements. The sediments in the study region are divided into 11 geological series or 43 stages and 16 rock types. The results show a striking relation between indoor Rn concentration and the geological factors.

Air Pollutants, Radioactive↗
PubMed1990

Expression of the Epstein-Barr virus genome in a nasopharyngeal carcinoma epithelial tumor cell line.

An epithelial tumor cell line was recently established from a biopsy specimen of a nasopharyngeal carcinoma (NPC), and designated HONE-I. Uncloned (parental) HONE-I and HONE-I clone (C)-40 cells were found to contain latent Epstein-Barr virus (EBV). Expression of the latent EBV genome in HONE-I C-40 cells has been examined. It was possible to detect a small percentage of cells spontaneously synthesizing EBV early antigen (EA) and virus capsid antigen (VCA) by immunofluorescence (IF). In addition, the EBV nuclear antigens (EBNA-I and EBNA-2), as well as the EBV latent membrane protein (LMP) were detected in the HONE-I cells. Attempts were made to induce the latent EBV genome in these cells with iododeoxyuridine (IUdR). We observed a significant increase in the number of EA/VCA-positive cells, an increase in EBV DNA, the synthesis of virus particles, and the rescue of infectious virus after treatment of HONE-I C-40 cells with IUdR. The HONE-I C-40 cells should facilitate studies of the expression and regulation of the EBV genome in NPC epithelial tumor cells, which have not previously been available.

Antigens, Viral↗
PubMed1990

Establishment and characterization of two epithelial tumor cell lines (HNE-1 and HONE-1) latently infected with Epstein-Barr virus and derived from nasopharyngeal carcinomas.

Two epithelial tumor cell lines were established from biopsy specimens of 2 nasopharyngeal carcinomas (NPC) and designated HNE-1 and HONE-1. Uncloned HNE-1 cells were found to be Epstein-Barr virus (EBV) DNA-positive when examined by Southern blot analysis up to passage 35, after which the EBV genome could no longer be detected. A similar loss of EBV DNA took place in uncloned HONE-1 cells. However, HONE-1 clone 40 cells are still EBV DNA-positive up to passage 42 thus far and cell cultures contain 85-90% EBV nuclear antigen (EBNA)-positive cells. The HNE-1 cell line has been passaged more than 100 times and the uncloned HONE-1 cells more than 90 times. The tumorigenicity of the HNE-1 and HONE-1 cells was demonstrated by tumor induction in nude mice. Karyotypic analysis of the HNE-1 cells demonstrated an aneuploidy with a modal chromosomal number of 74 at passages 5 and 101 at passage 20; 18 marker chromosomes were identified. We have continued to map the EBV genome latently associated with the HNE-1 and HONE-1 cells using the Bam HI, EcoRI or Hind III restriction enzymes. Using EcoRI fragments A-K as probes, we found that HNE-1 EBV DNA is different from B95-8 and HR-1 EBV DNA in the EcoRI-C region. The Bam HI map for HONE-1 EBV DNA is very similar to the B95-8 map; it contains the Bam HI-Y fragment but without Bam HI B' and WI'. Differences were observed between HONE-1 EBV DNA and B95-8 DNA using the Hind III restriction enzyme. There was no evidence of spontaneous expression of the latent EBV genome in HNE-1 cells, and attempts to induce replication of the latent EBV genome and rescue infectious virus have failed, suggesting a tightly restricted virus genome.

Animals↗
PubMed1989

Two epithelial tumor cell lines (HNE-1 and HONE-1) latently infected with Epstein-Barr virus that were derived from nasopharyngeal carcinomas.

Two epithelial tumor cell lines were established from biopsy specimens of nasopharyngeal carcinomas (NPC). The specimens were taken from poorly differentiated squamous cell carcinomas of the nasopharynx. The tissues were prepared for cell culture and eventually two continuous epithelial cell lines were obtained and designated HONE-1 and HNE-1. Light and electron microscopic examination of these two cell lines demonstrated cells with an epithelial morphology including the presence of desmosomes. The HNE-1 cell line has been passaged more than 100 times and the HONE-1 cell line has been passaged more than 90 times. It was found that early-passage uncloned HNE-1 cells (passage 23) could be superinfected with the B95-8 and NPC-EBV isolates as demonstrated by the induction of Epstein-Barr virus (EBV)-specific early antigen(s) in a small percentage of the cells; HONE-1 cells could also be superinfected with EBV. Southern blot analysis detected EBV DNA in samples from uncloned HNE-1 cells at passages 12, 17, 21, 27, and 35. However, by passage 45, EBV DNA could no longer be detected in HNE-1 cells by Southern blot analysis. The EBV genome was detected in parental HONE-1 cells at subculture 9 and in clone 40 cells up to passage 40 thus far. When HNE-1 cells were examined for the expression of the EBV-encoded nuclear antigen (EBNA) at passage 12, only about 10% of the cells were found to be positive. The percentage of EBNA-positive HNE-1 cells decreased as the cells were passaged. A similar loss of EBNA was observed in uncloned HONE-1 cells, but not in HONE-1 clone 40 cells. In clone 40, which has been passaged 40 times thus far, 85-90% of the cells are still EBNA-positive. The data suggest that EBV genome-positive HNE-1 and HONE-1 cells were lost as the cells were cultivated in vitro and that cloning the cells at an early passage level may be critical in maintaining EBV genome-positive epithelial NPC cells. These EBV genome-positive epithelial NPC cell lines will be useful for studying the association of EBV and NPC.

Antigens, Viral↗