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Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 307 records · Page 17Linked to original sources
PubMed1998

[The effect of ultrapure hyaluronic acid with different molecular weights on the healing of porcine full thickness skin wound].

Hyaluronic acid (HA) is an extracellular matrix having a high molecular weight. This study is to investigate (1) whether the ultrapure HA had effect on the healing of full thickness skin wounds in animals, and (2) the relation between the effect of HA and the size of the molecular weight of HA. The ultrapure HA with different molecular weights and HA with intermediate molecular weight were applied topically to the wounds from removal of full thickness of skin and topical application of normal saline was used as control. At 21st, day after the topical application, the tensile strength was reduced in wounds of groups of HA with high and intermediate molecular weights, but not in the group of low molecular weight. Using laser-Doppler scanning of the dynamic changes of the wound perfusion, in the 3rd day the blood supply to the wound was reduced in HA groups of high and intermediate molecular weights, but at the 7th day, the blood supply of all wounds in the two groups was increased. The study revealed that HA with different molecular weights had different actions on the contraction of wounds, the angiogenesis of the granulation tissues and the healing strength of the wounds. It was indicated that hyaluronan could be used for wound treatment or as a carrier, but its accurate composition must be carefully noted.

Animals↗
PubMed1998

[Evaluation of the growth and contraction of composite skin].

OBJECTIVE: To evaluate the growth and contraction of different composite skin grafts. METHODS: The status of the following composite skin grafts was evaluated over 2 years: allogeneic sucking pig dermis and autologous epidermis (group 1, n = 19), allogeneic young pig dermis and autologous epidermis (group 2, n = 7), autologous epidermis (group 3, n = 8). The effects of gestation on the composite skin grafts were also assessed. RESULTS: It showed that composite skin grafts had smooth surface and no scar formation during 2 to 124 weeks after transplantation. After week 36, the surface area of each group enlarged with different growth rates: group 1 > group 2 > group 3 (P < 0.01). Whole piece grafting was significantly better than joining together of smaller pieces after week 24 (P < 0.001). During pregnancy, CS had good growth ability and elasticity (P < 0.01). Histological study showed that group 1 had rapid growth of skin papillae and epidermal ridges similar to normal skin at week 24. CONCLUSION: As CS graft with trypsin treated allogeneic sucking pig dermis as a substitute for dermis showed the advantages of rapid growth, good elasticity and stability, it is suggested that it could be used in clinical practice.

Animals↗
PubMed1998

[Relationship between IL-1 beta and TNF-alpha in subretinal fluids of rhegmatogenous retinal detachment with PVR].

The concentrations of IL-1 beta and TNF-alpha in subretinal fluids from 49 patients with rhegmatogenous retinal detachment with proliferative vitreoretinopathy(PVR) were measured by Enzyme-linked immunosorbent assay (ELISA). The results showed that all subretinal fluids contained IL-1 beta, their concentrations were positive correlation with severity of PVR (r = 0.677) and no correlation with age, sex, holes, ranges and times of retinal detachment, TNF-alpha was detected in 18/49 subretinal fluids including 2 patients with PVR-1 beta and 16 patients with PVR-C and the above cases. It suggested that IL-1 beta and TNF-a are involved in the pathogenesis of PVR.

Adolescent↗
PubMed1998

[Study on the antimutagenicity of curcumin].

Curcumin is a coloring additive used in food, which has many biological functions. In order to provide basic information on its anticarcinogenicity, the antimutagenicity of curcumin was determined by Ames test and micronuclei test. The results indicated that curcumin (60-250 micrograms/plate) inhibited the revert mutant induced by 2, 7-diaminofluorene (2AF) with S-9 in TA98 and in TA100. The inhibitory rates are 29.5%-55.9% and 37.5%-59.1% respectively. Before the injection of cyclophosphamide (CP), mice were given with curcumin (60, 120, and 240 mg/kg) orally once a day for a week. The results revealed that curcumin reduced the micronuclei formation induced by CP. The inhibitory rates of curcumin are 43.7%, 56.9%, and 63.9% respectively, which are different from that of the positive control significantly.

Animals↗
PubMed1998

Detection of hepatitis C virus RNA sequences in hepatic portal cholangiocarcinoma tissue by reverse transcription polymerase chain reaction.

OBJECTIVE: To detect hepatitis C virus (HCV) RNA sequences in the hepatic portal cholangiocarcinoma tissues and their relationship. METHODS: RNA was extracted from paraffin-embedded cholangiocarcinoma tissues of 6 patients by guanidinium method, subjected to reverse transcription and then amplified by double PCR technique using nested primers from the highly conserved 5' noncoding region of HCV genome. RESULTS: HCV RNA of 5' NT sequences was found in the hepatic portal cholangiocarcinoma tissues of 5 out of 6 (83%) patients. CONCLUSIONS: HCV RNA sequences present with high infectious rate in cholangiocarcinoma, and reverse transcription polymerase chain reaction (RT-PCR) assay using primers derived from 5' NT region of HCV sequence is most useful in detecting HCV infection. The development of cholangiocarcinoma awaits further studies.

Adenocarcinoma↗
PubMed1998

[Studies on the role of colchicine in bleomycin-induced pulmonary fibrosis in rats].

OBJECTIVE: It has well been known that cytokines and extracellular matrix protein (ECM) have played an important role in pulmonary fibrosis in animal model as well as in patients. The purpose of this study was to evaluate the suppressive effect of colchicine (Colc.) in bleomycin (BLM)-treated rats. METHOD: Consecutive changes of interleukin-6(IL-6) and interleukin-8 (IL-8) released by alveolar macrophage (AM) were measured with murine B-cell hybridoma 7TD1 cells and micro membrane filter test. ECM and lipid peroxidation were observed with radioimmunoassay and biochemical assay respectively. RESULT: (1) Colc. significantly suppressed release of IL-6 by AM from day 7 to 28 (P < 0.05). But the level of IL-6 remained higher than that of the control. On the day 1 to 3, IL-8 released by AM markedly decreased (P < 0.01) and the peak of IL-8 secretion had not appeared. (2) Colc. had no protective effects on AM lipid peroxidation injury. (3) Colc. markedly decreased the level of fibronectin (FN) by AM on day 7, 14 (P < 0.01), as well as the level of laminin (LN) in bronchoalveolar lavage fluid (BALF) on day 7 to 28. However, the level of LN remained higher than that of control. (4) Colc. lessened the collagen deposition, and the lung hydroxyproline (HYP) content decreased on day 7, 14 and 28 (P < 0.05) compared with that of the control. (5) Colc. decreased exudation of inflammatory cells in the early response, as well as the degree of fibrosis in the late stage. CONCLUSION: Lipid peroxidation of AM might be one of the mechanisms of tissue injury and of AM activation, which increases the release of cytokines (IL-6, IL-8) and deposition of extracellular matrix proteins (FN, LN). Colc. exertes somewhat inhibitory effects on the process of pulmonary fibrosis in animal model. Factors other than AM and its cytokines might also be involved in the pathogenesis of pulmonary fibrosis in experimental rats.

Animals↗
PubMed1998

[Nervous system damage in patients with sarcoidosis].

OBJECTIVE: For the purpose to evaluate the clinical characteristics of nervous involvement in sarcoidosis patients, and to improve the diagnostic skills. METHOD: 92 cases with sarcoidosis were reviewed, and 5 of them with damages to nervous system were retrospectively analyzed. RESULT: One of the 92 cases was proved to be brain sarcoidosis by autopsy, and 4 presented damages to meninges, cranial, spinal and peripheral nerves. The clinical manifestations of the above 5 cases included epilepsy, intracranial hypertension, motor weakness, facial paralysis and dysopia. CONCLUSION: Clinical manifestations of patients with sarcoidosis of the nervous system are varied. Sarcoidosis may be one of the potential causes of some unproven abnormalities in brain, spinal cord, cranial and peripheral nerves.

Adult↗
PubMed1998

[Changes in endoneurial fluid pressure in the crushed facial nerve].

OBJECTIVE: To investigate the changes in endoneurial fluid pressure (EFP) and diameter of the crushed facial nerves in guinea pigs in order to determine whether there is necessity and the opportunity of the facial nerves decompression in different stage after injury. METHODS: EFP were measured using a servo-nulling micropipette system in the normal and crushed facial nerves. RESULTS: The results showed that the EFP in the facial nerve increased significantly after compression. The highest pressure of EFP 12.94 +/- 1.69 mmHg occurred at the end of the first week after injury, which was 4 to 5 times as great as that of normal ones. This change lasted about two weeks, then it returned to normal at the third or the fourth week. The largest diameter of the facial nerve 1.01 +/- 0.08 mm was seen at the end of the first week after crush injury. CONCLUSION: It suggested that the servonulling micropiette system was useful in evaluating the pathogenesis of facial palsy. It could provide the laboratory basis for facial nerve decompression.

Animals↗
PubMed1998

[Computer assisted ENT surgery system].

This paper describes a novel computer assisted ENT surgery system which is based on high-performanced 3D optical localizer and the combinational registration method for matching between pre-operative and intra-operative information. Preliminary results on cadaver specimen show the system is suited for clinical ENT surgery.

Equipment Design↗
PubMed1998

[An effective method of mutual interference coefficients for correcting spectral interferences in routine ICP-AES for multielement analysis].

An effective method was used to correct spectral interferences in routine ICP-AES for multielement analysis. In this method, all the components in an analysed object were considered to be related to each other, a strict mathematical model was applied and the mutual interference coefficients obtained from the usual artificial samples were replaced by those from natural standard samples which had the some matrix as the samples to be analysed. These mutual interference coefficients were used to correct the analysis data of GSD samples, and the results were mostly more precise than those corrected by the coefficients obtained from artificial samples. The correcting speed of this method is quick enough to satisfy the requirement of real-time correcting of analysis.

English Abstract↗
PubMed1998

Oltipraz chemoprevention trial in Qidong, People's Republic of China: modulation of serum aflatoxin albumin adduct biomarkers.

In 1995, 234 adults from Qidong, People's Republic of China, were enrolled and followed in a Phase IIa 4-methyl-5-(N-2-pyrazinyl)-1,2-dithiole-3-thione (oltipraz) chemoprevention trial. Residents of this area are at high risk for development of hepatocellular carcinoma, in part due to consumption of aflatoxin-contaminated foods. The intervention was a randomized, placebo-controlled, double-blind study. Elements of the study design and clinical outcomes have been recently published (Jacobson et al, Cancer Epidemiol. Biomark. Prev., 6: 257-265, 1997). The primary objective was to conduct a preliminary assessment of the ability of oltipraz to modulate levels of a validated biomarker of aflatoxin exposure and of the risk of hepatocellular carcinoma by determining levels of aflatoxin-albumin adducts in sera. Healthy eligible individuals were randomized into three arms to receive p.o. 125 mg of oltipraz daily, 500 mg of oltipraz weekly, or placebo for 8 weeks. There were no consistent changes in biomarker levels in the placebo arm over the 16-week observation period, nor was any apparent effect observed in the arm receiving 125 mg of oltipraz each day. However, individuals receiving 500 mg of oltipraz once a week for 8 weeks showed a triphasic response to oltipraz. No effect was observed during the 1st month of the intervention, whereas a significant (P = 0.001) diminution in adduct levels was observed during the 2nd month of active intervention and during the lst month of follow-up. A partial rebound in adduct levels toward baseline values was observed during the 2nd month postintervention. Linear regression models up to week 13 confirmed a significant (P = 0.008) weekly decline of biomarker levels in the group receiving 500 mg of oltipraz once a week. However, despite these effects relative to baseline values within the 500-mg weekly arm, there were no statistically significant differences in biomarker trajectories between treatment arms. The genotype for glutathione S-transferase M1, an oltipraz-inducible isoform involved in the detoxification of aflatoxin B1, did not appear to affect either baseline levels or rates of decline in the biomarker. A follow-up Phase IIb trial with a longer intervention period will be necessary to determine the full extent to which aflatoxin biomarker burden can be reduced and whether diminution of biomarkers can be sustained over the long term.

Adult↗
PubMed1998

Methylation alterations of the MyoD1 upstream region are predictive of subclassification of human rhabdomyosarcomas.

MyoD1 expression is a distinguishing characteristic of rhabdomyosarcoma. In this study, distinct methylation alterations were identified in the 5' flanking region of the MyoD1 gene from the two major subtypes, ie, alveolar and embryonal rhabdomyosarcoma. The MyoD1 methylation patterns of 26 rhabdomyosarcomas were compared with that of normal skeletal muscle and nonmuscle specimens by Southern blot analysis using methylation-sensitive restriction enzymes HhaI and HpaII. A 5-kb region immediately upstream of the MyoD1 coding sequence was found to be methylated in adult muscle and all nonmuscle tissues tested. The MyoD1 upstream region was unmethylated in the majority of the alveolar rhabdomyosarcomas (13 of 15, 87%) examined in this study. In contrast, 10 of 11 (91%) embryonal rhabdomyosarcomas showed a methylation pattern that was also observed in fetal muscle cells, in which the CpG sites in the MyoD1 upstream region were partially methylated. Our data suggest that the methylation status of the MyoD1 upstream CpG sites may be related to rhabdomyosarcoma tumorigenesis and may have valuable implications for its differential diagnosis.

Adolescent↗
PubMed1998

Equal distribution of competitive long-term repopulating stem cells in the CD34+ and CD34- fractions of Thy-1lowLin-/lowSca-1+ bone marrow cells.

CD34 antigen is present on most, if not all, human hematopoietic stem cells (HSCs). Consistent with this pattern of expression, we recently reported that primitive murine HSCs defined as competitive long-term repopulating units (CRUs) are highly enriched among CD34+ bone marrow (BM) cells (one CRU/2500 cells). However, in agreement with one recent report that some murine HSCs do not express CD34 (Science 273:242), we observed that 15% of phenotypically defined Thy-1lowLin-/lowSca-1+ (TLS) stem cells were CD34- by fluorescence-activated cell sorting. To examine further the nature of CD34 expression on murine hematopoietic cells, we separated TLS cells into CD34+ (0.022% of BM cells) and CD34- (0.005% of BM cells) fractions, confirmed their phenotype by reverse transcriptase-polymerase chain reaction analysis of CD34 transcripts, and evaluated them in a variety of in vitro and in vivo assays. The CD34+ TLS population contained most (93-95%) of the day 12 spleen colony-forming units (CFU-S) and in vitro colony-forming cells (CFCs). Cobblestone area-forming cells (CAFCs) able to proliferate on a murine bone marrow stromal cell line (SyS-1) represented one of every 5 CD34+ TLS and one of every 31 CD34 TLS cells. When lethally irradiated mice were injected with 100 CD34+ TLS cells, all animals survived and began to recover circulating leukocytes, platelets, and erythrocytes by 15 days. In contrast, only 40% of mice injected with 100 CD34- TLS cells were radioprotected, and hematopoietic reconstitution in surviving mice was not apparent until 21 days. The frequency of CRUs in CD34+ and CD34 TLS cells was determined by injecting limiting numbers of cells into lethally irradiated Ly-5 congenic hosts together with 10(5) "compromised" BM cells to provide radioprotection. CRUs able to regenerate and maintain lymphoid and myeloid cells for at least 6 months in primary and 5 months in secondary hosts represented one of every 156 CD34+ TLS and one of every 35 CD34- TLS cells. However, when normalized for the proportion of TLS cells that were CD34+ or CD34-, it was determined that the recovery of CRU among CD34+ and CD34- TLS cells was equivalent (46% and 54%, respectively). These data are consistent with the previous description of repopulating HSCs among CD34-c-kit+Sca-1+Lin- cells (Science 273:242, 1996) and provide additional evidence that TLS cells are functionally heterogeneous and can be further fractionated on the basis of CD34 expression. Overall, approximately 95% of CFCs, CFU-S, and CAFCs in the TLS population were found to be CD34+, whereas more primitive CRU were distributed equally among CD34+ and CD34 TLS cells. These results should enable better characterization of the most primitive stem cells in murine BM.

Animals↗
PubMed1998

[Detection of presymptomatic patients and heterozygotes with Wilson's disease by using haplotypes of microsatellites].

OBJECTIVE: To develop a rapid, exact and effective technique of gene diagnosis for the early diagnosis of patients with wilson's disease(WD) and detection of WD heterozygotes. METHODS: Five microsatellite (or short tandem repeat, STR) loci at D13S301, D13S316, D13S296, AFM238vc3 and AFM184xc5 were amplified by polymerase chain reaction(PCR). D13S301 was a locus within WD gene, the others were in the flank of WD gene. After detection of amplified fragment length polymorphism of the five STR loci with denaturing polyacrylamide gel electrophoresis(AFLP-PAGE), the STR haplotypes analyses were performed on 120 members in 23 WD families. RESULTS: The five STR loci had high polymorphism information content(PIC). PICs of D13S301, D13S316, D13S296, AFM084xc5 and AFM238vc3 were 0.89, 0.93, 0.91, 0.91 and 0.94 respectively. The STR haplotypes analyses confirmed that the two patients previously diagnosed doubtfully were WD patients definitely. Among 31 sibs without any clinical symptoms, 4 were diagnosed as presymptomatic patients, 8 as WD heterozygotes, 17 as normal homozygotes and 2 as doubtful presymptomatic patients. CONCLUSION: Haplotypes analysis of the five STR loci can provide high genetic information. It provides a new important technique in gene diagnosis of WD.

Adult↗