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Biomedical subjects

X J Ma

Publications and source records attributed to X J Ma.

At least 19 recordsLinked to original sources
PubMed2006

Microcalorimetric study on the growth and metabolism of microencapsulated microbial cell culture.

The rate of heat output is one of the suitable measurements of metabolic activity of the organism or its parts, down to the cellular or even the sub-cellular levels. In this paper, microcalorimetry was first applied to study the metabolic activity of microbial in both alginate-polylysine-alginate and alginate-chitosan-alginate microencapsulated cultures as well as in free non-encapsulated culture. The organisms used for the measurements were Escherichia coli and Saccharomyces cerevisiae. As a result of this work, it was found that, despite E. coli cell in free non-encapsulated culture has the highest metabolic rate due to the highest value of heat output, the proliferation of the cells terminates quickly with a lowest biomass formed. And we found also an obviously longer stationary phase in microencapsulated culture. As far as S. cerevisiae was concerned, it was found that there was also the highest value of heat output in free non-encapsulated culture, but the cell density was lower than that in microencapsulated culture. On account of the microcalorimetric and metabolic measurements, it can be concluded that more substrate can be used to convert to biomass in microencapsulated culture which means a higher biomass yield existed.

Alginates↗
PubMed2006

Microencapsulated nerve growth factor-expressing NIH3T3 cells-incorporated tissue engineering skin: a preliminary study.

INTRODUCTION: In order to find a suitable carrier to deliver the product of gene transfection to improve the performance of bioengineered dermis, we used microencapsulation and gene transfection technology together for the first time and found that it was feasible. METHODS: We used a recombinant nerve growth factor (pcDNA3.1+/NGF) to modify NIH3T3 cells genetically. Control of NIH3T3-NGF cells were encapsulated within microspheres composed of alginate-poly-L-lysine-alginate and cultivated in-vitro. The concentration of NGF released from the microencapsulated NIH3T3-NGF cells was confirmed using ELISA assay. We co-cultivated microencapsulated NIH3T3-NGF cells, NIH3T3 cells (control) with human keratinocytes and fibroblasts, and tested the percentage of cycle of these cells. The alkaline hydrolysis method was used to analyse the content of hydroxyproline (Hyp). Immunohistochemistry method was used to calculate the transformation efficiency from fibroblasts to myofibroblasts. RESULTS: The concentration of NGF released from the microencapsulated NIH3T3-NGF cells lasted about six weeks in the supernatant of bioengineered dermis in-vitro. The proliferation of keratinocytes, as well as the concentration of Hyp in supernatant of fibroblasts, were promoted about three times. Transformation efficiency from fibroblasts to myofibroblasts was increased approximately two-fold because of the bio-effects of NGF. Two kinds of microencapsulations were seeded into collagen which contained human fibroblasts to form bioengineered skin. Microencapsulated NIH3T3-NGF cells formed a thicker dermis. The concentration of Hyp in the bioengineered skin which indicated the level of collagen synthesis was increased due to existing NGF. CONCLUSION: Microencapsulated NIH3T3-NGF cells can be used to enhance performance of bioengineered dermis and it also can be deduced that other cytokines can be used to treat local wound areas.

Alginates↗
PubMed2002

Microorganisms in a high altitude glacier ice in Tibet.

Eighty-one strains of viable microorganisms were recovered from 23 samples collected from Ice Core 3 of Malan Glacier (China, 91 degrees 45.3' E, 35 degrees 48.4' N) drilled at high altitude (5620 m). All the strains were prokaryotes--75 of bacteria (including spore-forming ones) and 6 of actinomycetes. The characteristic genera differ from those of Arctic and Antarctic ice, in which many fungi and algae are widely distributed; this shows an difference of environmental conditions between Tibet and polar regions. The variation in number and species of Bacillus in different ice core layers implied changes of environmental conditions in the past.

Bacteria↗
PubMed2001

Genomic profiling of the response of Candida albicans to itraconazole treatment using a DNA microarray.

The application of genome-wide expression profiling to determine how drugs achieve their therapeutic effect has provided the pharmaceutical industry with an exciting new tool for drug mode-of-action studies. We used DNA chip technology to study cellular responses to perturbations of ergosterol biosynthesis caused by the broad-spectrum antifungal agent itraconazole. Simultaneous examination of over 6,600 Candida albicans gene transcript levels, representing the entire genome, upon treatment of cells with 10 microM itraconazole revealed that 296 genes were responsive. For 116 genes transcript levels were decreased at least 2.5-fold, while for 180 transcript levels were similarly increased. A global upregulation of ERG genes in response to azole treatment was observed. ERG11 and ERG5 were found to be upregulated approximately 12-fold. In addition, a significant upregulation was observed for ERG6, ERG1, ERG3, ERG4, ERG10, ERG9, ERG26, ERG25, ERG2, IDII, HMGS, NCP1, and FEN2, all of which are genes known to be involved in ergosterol biosynthesis. The effects of itraconazole on a wide variety of known metabolic processes are discussed. As over 140 proteins with unknown function were responsive to itraconazole, our analysis might provide-in combination with phenotypic data-first hints of their potential function. The present report is the first to describe the application of DNA chip technology to study the response of a major human fungal pathogen to drug treatment.

Antifungal Agents↗
PubMed2001

[Screening of anti-bacteria activity of extracts of Gaultheria leucocarpa var. yunnanensis].

OBJECTIVE: To further develop Gaultheria leucocarpa var. yunnanensis, anti-bacteria constituents in it were screened. METHOD: The constituents were extracted by chromatographic process. The anti-bacteria test was made with regulatory method of analysis. RESULT AND CONCLUSION: Anti-bacteria test with extracts of water, acetic ester and n-butanol showed that 3 extracts from 22 samples had anti-Staphylococcus aureus action, and the extracts from root and stem showed the same result. 2 extracts could kill Escherichia coli and Pseudomonas aeruginosa. The lower the concentrate, the less the anti-bacteria action was. These results suggested that not only essential oil but other ingredients from G. leucocarpa var.yunnanensis have anti-bacteria activity. Anti-fungi test of the same extracts didn't indicate remarkable action.

Anti-Bacterial Agents↗
PubMed2001

[Studies on resources of ethnomedicine Gaultheria leucocarpa var. yunnanensis].

OBJECTIVE: To study the resources of G. leucocarpa var. yunnanensis for further development of this drug. METHOD: Field investigating, consulting with relevant experts and looking into available specimens. RESULTS AND CONCLUSION: G. leucocarpa var. yunnanensis is widely distributed in the southern regions of the Yangtze River. The field investigation suggests that the distribution center is situated in Yunnan province, mainly in Kunming, Chuxiong and Dali counties. The climate in these areas is moderate and moist. G. leucocarpa var. yunnanensis is not a dominant species in this natural environment. In some places, it grows with other species of Gaultheria, such as G. fragrantissima, G. tetramera, G. griffithiana and G. leucocarpa var. cumingiana. It is distributed at altitudes from 400 m to 3,500 m. Accustomed to different sunshine conditions, G. leucocarpa var. yunnanensis prefers stronger sunlight and commonly grows on sunny slopes, seldom in dense forest, propagating itself by roots. As a folk medicine, G. leucocarpa var. yunnanensis is commonly used to treat rheumatic arthritis(RA), dazzling, suppressed menstruation, cold, cough, asthma, strain hematemesis, eczema, ascites, wound, amebic dysentery, acute and chronic prostatitis. It is suggested that further pharmacological and clinical researches of this plant be concentrated on the treatment of RA and relief of aches.

China↗
PubMed2001

[Studies on chemical constituents of Gaultheria leucocarpa var. Yunnanensis (Franch.) T. Z. Hsu & R. C. Fang].

OBJECTIVE: To separate and identify the chemical constituents of the aerial part of Gaultheria leucocarpa var. yunnanensis. METHOD: The compounds were extracted with solvents, isolated by column chromatography and identified by spectral analysis. RESULT: Four compounds were identified as n-dotriacontane and its homologous compound(1), ursolic acid(2), vanillic acid(3), and quercitrin(4). CONCLUSION: The compounds 1, 4 were obtained from the plant for the first time, and 2 and 3 were from above-ground part of the plant for the first time.

Alkanes↗
PubMed2001

[Systemic breeding of the new variety of Biantiao ginseng (Panax ginseng)].

OBJECTIVE: To breed new varieties of Biantiao ginseng for high yield and fine quality. METHODS: Systemic breeding methods were applied. About 3,000 outstanding Biantiao ginseng roots were selected and planted in breeding field, and self-crossed for four generations. During the course, inferior lines or plants were rejected. Then strain comparison, identification of resistance to black-speck disease, and analysis of active compositions were carried out. RESULTS: "Biantiao 1" (BT1), the first new variety of Biantiao ginseng, with green stems and thick, long, elegant roots and median resistance to black-speck disease, has been harvested since 20 years. The percentage of Biantiao ginseng roots and yield were 15% and 30% higher than the control's respectively. The content of total ginsenosides and the main monomers was 1.8%-2.5% higher than the control's. The characteristics of overground part and root of BT1 were uniform and stable. CONCLUSIONS: BT1, a new excellent ginseng variety, has a good potential value to be generalized in ginseng production.

Breeding↗
PubMed2001

[Effects of growth regulator, full exposure and mist spray on the cutting of Eucommia ulmoides].

OBJECTIVE: To study the effects of growth regulator on the cutting method of Eucommia ulmoides seedlings. METHODS: Treated with H2O (CK), NAA, 6-BA and NAA + 6-BA for 4 hours, respectively, cuttings of 4-year and 20-year trees were cultured for 45-60 days under the shed or full exposure and mist spray. The growth of the cuttings was observed periodically. The number of the roots, the root length, the callus and the death rate were investigated after harvest. RESULTS: Compared with the cutting from 4-year-old tree, the cutting from 20-year-old tree developed better. The rate of stroking root in treated group was 14 times as much as CK group. Other agronomic traits such as the number of the roots, the root length, the callus, the number of the leaves and the death rate of the cuttings in treated group were all better than that of the cuttings in CK group. The cultural time in treated group reduced by 15 days than that of CK group. CONCLUSIONS: The present study shows that both full exposure mist spray and growth regulators have remarkable effects on cuttings of tree with different ages for rooting or forming callus.

Eucommiaceae↗
PubMed2000

Alternative splicing of the histamine H(3) receptor mRNA at the third cytoplasmic loop is not detectable in humans.

Histamine regulates neurotransmitter release in the central and peripheral nervous systems through H(3) presynaptic receptors. cDNAs coding for human, guinea pig and rat histamine H(3) receptors have recently been cloned. Cloning of rat and guinea pig H(3) receptors demonstrated the existence of multiple isoforms displaying deletions in the third cytoplasmic loop coding region. We investigated whether a similar splicing pattern might also occur in the human H(3) gene. Using both RT-PCR and RNase protection assays, we detected H(3) receptor mRNA expression in human brain, testes and a cell line expressing recombinant human H(3) receptor (SK-N-MC/H(3)). In all samples tested by both detection methods, only the long mRNA form was detected. We could not find any evidence that humans express other forms equivalent to that seen in the rat or guinea pig. If the alternative splicing seen in rats and guinea pigs presents itself through pharmacological variation, our current findings then have implication for the use of rats or guinea pigs as model system for the development of therapeutic targeting the human H(3) receptor.

Alternative Splicing↗
PubMed2000

Cleavage and phosphorylation of XRCC4 protein induced by X-irradiation.

We report the p35 and p60 forms of XRCC4 protein, appearing in human leukemia MOLT-4 or U937 cells following X-irradiation or hyperthermia. p35 appeared in conjunction with the cleavage of DNA-dependent protein kinase catalytic subunit (DNA-PKcs) and the fragmentation of internucleosomal DNA, and was suppressed by Ac-DEVD-CHO. p35 was also produced in vitro by treating MOLT-4 cell lysate with recombinant caspases, suggesting that p35 was a caspase-cleaved fragment of XRCC4 in apoptotic cell death. p60 was sensitive to treatment with phosphatase or wortmannin and was undetectable in M059J cells deficient in DNA-PKcs. However, p60 was found in ataxia-telangiectasia cells after irradiation. These results indicated p60 as a phosphorylated form of XRCC4, requiring DNA-PKcs but not ataxia-telangiectasia mutated (ATM).

Androstadienes↗
PubMed2000

Tbt-1, a new T-box transcription factor induced in activated Th1 and CD8+ T cells.

Differentiation of CD4+ T cells into T helper (Th) 1 or Th2 cells requires the cytokines interleukin (IL)-12 and IL-4, respectively. However, transcription factors that regulate expression of Th1 or Th2 cell-specific genes remain largely unclear. In the present study, a new Th1-specific transcription factor, named Tbt-1 (T-box protein expressed in T lymphocytes), was identified. Tbt-1 is a novel member of the T-box family, which is characterized by a conserved T-box DNA-binding domain. Unlike other known T-box proteins that regulate embryo development and organogenesis, Tbt-1 expression is restricted to adult lymphoid organs. Tbt-1 mRNA is only detected in peripheral lymphoid tissues such as spleen, lymph nodes, and blood leukocytes, but not in thymus or bone marrow. Tbt-1 mRNA is not detected in resting T cells but is strongly induced in differentiating Thl cells and CD8+ cytotoxic effector cells. In contrast, Tbt-1 expression was not observed in the entire process of Th2 cell differentiation. In addition, phylogenetic analyses indicate that Tbt-1 co-evolved with adaptive immune responses. Thus, Tbt-1 is the first T-box transcription factor shown to be specific for Th1 cell differentiation.

Amino Acid Sequence↗
PubMed2000

Xenotransplantation of microencapsulated bovine chromaffin cells into hemiparkinsonian monkeys.

This study examines the effects of xenografts of microencapsulated bovine chromaffin cells (BCCs) on the rotational behavior of hemiparkinsonian monkey recipients. In addition, it determines the content of monoamine neurotransmitters and their major metabolites in the neostriatum in hemiparkinsonian monkeys. The hemiparkinsonian model in monkeys was induced by a unilateral intracarotid injection of methyl-phenyl-tetrahydropyridine (MPTP). Unencapsulated BCCs, BCCs microencapsulated in alginate-polylysine-alginate (ALA) membranes as well as empty microencapsules were grafted into the neostriatum of the hemiparkinsonian monkeys. Following the transplantation the hemiparkinsonian symptoms subsided and the number of rotations induced by apomorphine decreased for up to nine months in the group of recipients grafted with microencapsulated BCCs, while only a temporary improvement (one month) was detected in the recipients of the unencapsulated BCCs. No change was observed in the recipients of empty microencapsules. Dopamine and its metabolites were found considerably depleted in the MPTP-lesioned side versus the unlesioned side of the neostriatum in the hemiparkinsonian monkeys(P<0.05).

3,4-Dihydroxyphenylacetic Acid↗
PubMed2000

[Application of multiple tissue expanders for repair of facial and neck scar].

OBJECTIVE: To repair facial and neck scar using tissue expanding technique. METHODS: From January 1991 to January 1995, 16 cases with facial and neck scar were treated. Multiple tissue expanders were put under the normal skin of facial and neck area, after being fully expanded, the scars were excised and the expended skin flaps were transplanted to cover the defects. The size and number of tissue expanders were dependent on the location of the scars. Normally, 5 to 6 ml expanding volume was needed to repair 1 cm2 facial and neck defect. The incisions should be chosen along the cleavage lines or in the inconspicuous area, such as the nasolabial fold or submandibular region. The design of flap was different in the face and in the neck. In the face, direct advanced flap was most common used, whereas in the neck, transposition flap was often used. Appropriate tension was needed to achieve smooth and cosmetic effect. It was compared the advantages and disadvantages of several methods for repair of the defect after facial and neck scar excision. RESULTS: Fifteen cases had no secondary deformity after scar excision. Among them, 1 case showed blood circulation disturbance and cured through dressing change. Ten cases were followed up and showed better color and texture in the flap, and satisfactory appearances. CONCLUSION: Tissue expanding technique is the best method for the repair of facial and neck scar, whenever there is enough expandable normal skin.

Adolescent↗
PubMed2000

[Development of prefabricated flaps].

OBJECTIVE: To sum up the experimental development and clinical application of prefabricated flap. METHODS: The reported experimental results and clinical application of prefabricated flap extensively reviewed. RESULTS: Previous studies had proved that the revascularization of prefabricated flap mainly through anastomoses of implanted vessels and the original vessels of the flap, the implanted vessels slowly formed a new and complete blood vessel network, which could dominate the whole flap, three to four weeks later, the new vessels were mature and the flap could be transferred. Clinically, the superficial temporal vessels, gastroepiploic vessels, circumflex femoral vessels and thoracodorsalis vessels could be harvested for prefabricated flap with satisfactory results. CONCLUSION: Prefabricated flap provides a new method for the treatment of complicated defects.

Arteries↗
PubMed2000

[Comparison of ITS sequences between wild ginseng DNA and garden ginseng DNA].

OBJECTIVE: To compare the genetic differences between wild ginseng and garden ginseng (Panax ginseng). METHOD: The sequences of ITS1 and ITS2 of wild ginsengs were determined on LKB DNA sequencing station through Si-liver Sequence DNA Sequencing System. The sequencies were aligned with DNA SIS software. RESULTS AND CONCLUSION: The ITS1 and ITS2 of Panax were 220-221 and 222-224 bases in length respectively. In Panax ginsehg, the seqences of ITS1 were very stable, but ITS2 were changeable. The ITS2 sequences of No. 87 and No. 110 of the wild ginseng collected from Fusong Heilongjiang (China) were exactly the same as those of No. U41680(Jun Wen) and No. U41682(Jun Wen) of garden ginseng collected from Heilongjiang Province (China) and Korea respectively, but different from those of No. U41681(Jun Wen) from Hubei Province (China) in three bases (447, 449, 450) The result implies that the cultivated ginsengs may have been introduced from two different populations of the wild ginseng.

Base Sequence↗
PubMed2000

[A study on AFLP fingerprinting of land races of Panax ginseng L].

OBJECTIVE: To obtain more information on DNA fingerprintings of five land races of Chinese ginseng, namely, Damaya (DMY), Changbo (CB), Yuanbangyuanlu (YBYL) and Huangguo (HG). METHODS: The five land races were detected by amplified restriction fragment polymorphism (AFLP) markers with 11 combined primers (M2, M3, M16, M20, M53, M56, M57, M68, M69, M72, M84 in Mse I). RESULT AND CONCLUSION: Only 4.6% polymorphic sites was found. It was further verified that only a little diversity existed among the land races. The polymorphic sites of CB were much more than those of the others, which suggests that there are more heterozygotes in CB populations, and it is closer to wild ginseng than the others.

DNA Fingerprinting↗