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Biomedical subjects

B Chen

Publications and source records attributed to B Chen.

At least 451 records · Page 25Linked to original sources
PubMed1994

Analysis of human hematopoietic stem cell populations.

Purification of human hematopoietic stem cells (HSC) may be useful clinically for preparation of tumor-free grafts to be used for autologous transplantation and as targets for gene therapy. To analyze the phenotype of the human HSC, assays were used that measure the unique properties of stem cells, i.e., their long-term repopulating ability and their multilineage potential. These assays include: (1) an in vitro long-term hematopoietic culture system, using the murine bone marrow stromal cell line SyS1, which supports both B lymphopoiesis and myelopoiesis; (2) fetal human bone grafts implanted in SCID-hu mice, in which maintenance of CD34+ cells and B and myeloid differentiative capacity of candidate stem cell populations may be measured; (3) fetal human thymus grafts in SCID-hu mice, which allow the analysis of in vivo T-cell potential of a candidate stem cell population. Stem cells in adult bone marrow (ABM) or cytokine-mobilized peripheral blood (MPB) are thought to express CD34 but lack expression of markers indicating lineage commitment. This CD34+ Lineage- (Lin-) subpopulation has been isolated by fluorescence-activated cell sorting and tested for activity in the assays described here. CD34+ Lin- cells from both ABM and MPB demonstrated long-term engraftment in the SCID-hu bone model. This CD34+ Lin- population can be subfractionated further using an antibody to Thy-1. The Thy-1+ subset of CD34+Lin- cells is enriched for both long-term culture-initiating cells (LTC-1C) and has the ability to engraft in vivo.

Animals↗
PubMed1994

[Block hydroxyapatite artificial bone in augmentation rhinoplasty: experimental study and clinical applications].

The lower dense block hydroxyapatite artificial bone (BHAB), a new material for augmentation rhinoplasty, having the characteristic of easy to be carved and contoured, was used in 18 New Zealand white rabbits. The results demonstrated BHAB had good biocompatibility and well maintained the augmented contour. Satisfactory effects were gained in 13 clinical applications.

Animals↗
PubMed1994

[The effects of naloxone and electroacupuncture on the release of GnRH from female rat's preoptic area].

By means of push-pull perfusion technique and the special radioimmunoassay we determined the GnRH concentration of the perfusates from preoptic area (POA) in ovariectomized (OVX) and intact (INT) female rats, to observe the influence of naloxone and electroacupuncture (EA) on the release of GnRH and beta-endorphin from POA. The results show that the basic GnRH level of POA perfusate in OVX was 271.8 +/- 77.5pg/ml and that in INT was 52.4 +/- 11.1pg/ml. There was a significant difference between the basic levels of two groups (P < 0.02, n = 12). No difference of beta-endorphin basic level in OVX and INT was found. The GnRH level of POA perfusate in OVX was increased by 146.6 +/- 46.5pg/ml (P < 0.01, n = 12) 30 minutes after intraperitoneal administration of naloxone, but no obvious change was found in INT following naloxone administration. EA treatment had no effect on the release of GnRH and beta-endorphin in both OVX and INT. The results suggest that the negative feedback of estrogen may be a major regulative factor of GnRH under the normal condition and after the abolition of estrogen feedback induced by ovariectomy the central opioid peptide might be the main regulative mechanism for GnRH.

Animals↗
PubMed1994

[Synthesis of terephthalic acid derivatives and their activity on human promyelocytic leukaemia cells HL-60].

There were 13 derivatives of terephthalic acid were synthesized, in which 9 compounds were not found in literature. The 9 compounds were evaluated for their differentiation-inducing activities on human promyelocytic leukaemia cells HL-60. Compounds N1 and N4 possessed potential activity. Their percentage of differentiating effect was 55% (5 x 10(-6) mol/L), but it was less than that of retinoic acid (79%, 10(-7) mol/L).

Cell Transformation, Neoplastic↗
PubMed1994

[The relationship between opportune administration of antibiotics and infection after burn injury: an experimental study].

45 male rabbits with 15% III degree burn were infected with Pseudomonas aeruginosa. They were divided into three groups: the prevention group, in which cpz (cefoperazone) was immediately administered after the scald at the dose of 25 mg/kg with an interval of 1/12 h for a total of 4 doses; the treatment group, in which cpz was administered 48 th after the scald with the dosage same as above; control group in which cpz was not administered. The findings were as follows: In the prevention group, gross observation showed dessication and crustation of the surface of the wound within 1 week after the scald. By employing immunofluorescent antibody it was found that P. A existed only in the superficial layer. However, ulceration and exudation were found in the control and treatment group within 3 or 4 days after the scald, and P. A was shown to have invaded the deep muscular tissue to cause intermuscular septal abscess. The positive rate of blood culture of bacteria in the prevention group (10/81) was significantly lower than that of the treatment (15/57) and the control groups (21/76, P < 0.05). The death rate of the prevention group (2/15) was significantly lower than that of the treatment (10/15) and the control groups (9/15, P < 0.05). The above finding showed that antibiotics specific to the infectious organism of the wound in extensive burn patients should be given in the early exudation stage in order to ward off invasive infection.

Animals↗
PubMed1994

[Application of the island skin flap to repair facial soft tissue defects].

We have applied the island skin flap for facial reconstruction and repair in 45 cases with very satisfactory results. The advantages of the island flap are: (1) having relatively long and flexible pedicle for transfer, (2) having good blood supply, (3) with well-matched color and texture and (4) avoiding the second operation. The characteristics and technical problems are discussed in the paper.

Adolescent↗
PubMed1994

[The effects of electroacupuncture treatment on nucleolar organizer regions of adrenal cortex in ovariectomized rats].

The present paper reports the morphometric analysis of nucleolar organizer regions (NORs) of the adrenal cortex in ovariectomized rats following electroacupuncture (EA) using argyrephil (Ag-NOR) method for NORs. Animals were divided into four groups, the control group (CT group, n = 4), the EA group (n = 3), the ovariectomized group (OV group, n = 4) and the ovariectomized electroacupuncture group, (OV+EA group, n = 7). The number of AgNORs of 100 cells from zona fasciculata of the adrenal cortex in each case of all groups was counted at random and the mean +/- SE (number/cell) in each group was calculated as follows: OV+EA group 2.71 +/- 0.26, OV group 1.62 +/- 0.15, EA group 1.21 +/- 0.04 and CT group 1.48 +/- 0.03. The mean of AgNORs in OV+EA group differed highly significantly from the other three groups (P < 0.01) tested by ANOVA and LSD method, No significant distinction was found among the OV group, EA group and CT group. Gross specimen examination showed that adrenal glands in OV+EA were significantly heavier than those in the other three groups (P < 0.01). Vaginal smears showed that a response like that of estrogen-induced with exfoliative cells appeared in the OV+EA group rats following EA. EA had no influence on the change of exfoliative cells in EA group. The results suggest that EA may promote the synthesis and secretion of the adrenal steroid hormones, the androgen of which will then be transformed into estrogen in other tissues, thus compensating the deficiency of estrogen induced by ovariectomy.

Adrenal Cortex↗
PubMed1994

[Antitumor activity of monoclonal antibody MI2 against immunosuppressive acidic protein in vitro].

In vitro antitumor activity of monoclonal antibody MI2 that was made by our laboratory to direct against immunosuppressive acidic protein (IAP) was observed with MTT assay for cytotoxicity. The results showed that the growth of human gastric cancer cell line SGC 7901 was inhibited significantly (P < 0.01) when MI2 was added at a concentration of 7.81 mg/L or higher. The inhibition activity of MI2 appeared to be dose dependent. Increased cytotoxicity (up to 206.3%) of LAK cells against SGC7901 could be remarkably (P < 0.01) induced by addition of MI2 at a concentration of 1.95 mg/L, so the ratio of effector to target was 10:1. The enhancing effect of MI2 on LAK cell activity was also dose dependent. The antitumor activity of MI2 was not associated with human complements.

Antibodies, Monoclonal↗
PubMed1994

[Study on genetic epidemiology of albinism].

Segregation analysis and consanguinity analysis were applied to 37 albinism families ascertained from Shandong province (P. R. China) to study the genetic heterogeneity of the disease. Our results show that albinism is an autosomal recessive disease with multilocus. The least number of the detrimental loci is 8, The average frequence of detrimental genes is 0.0023, and 3.83% individuals in general population are carriers. The incidence among the offsprings of the first cousin marriages would be 22 times higher than that in the general population.

Albinism↗
PubMed1994

[Investigation of nuclear lamina in Tetrahymena thermophila].

The nuclear lamina in the nuclei of Tetrahymena thermophila was investigated using the techniques of selective extraction and embedment-free electron microscopy, as well as immunofluorescence staining. By means of immunoblotting and protein isolating, the lamina was found to consist mainly of a 66 KD polypeptide. While rabbit-anti-lamins polyclonal antibodies crossreacted with this protein, neither murine-anti-lamin A&C mAB C23 nor murine-anti-lamin III mAB 223 showed positive reaction with it. It was also demonstrated that the lamin is not so rich as that in mammalian cells. The existence of lamina in T. thermophila, a unicellular organism, seems to show that the lamina is a basic characteristic structure of eukaryotic cells, and that the function of the lamina may not be limited to the process of breakdown and reconstitution of nuclear envelope during mitosis.

Animals↗
PubMed1994

[The physiological function of plasma apoA-I--the anti-viral effects of apoA-I and its fragments].

Apolipoprotein A-I (apoA-I), the major protein of plasma high density lipoproteins, was found to inhibit herpes simplex virus type I (HSV-I) induced cell fusion at physiological concentrations (mumol/L). Plasma apoA-I from three different species was used to study the anti-viral effects by microneutralization test. Marked inhibition of virus-induced cell fusion was observed when the virus or the cells were pretreated with apoA-I, suggesting that apoA-I may have a direct effect on the virus and the cells. This function may be related to the structure of apoA-I.

Animals↗
PubMed1994

Changes in employment, insurance, and income in relation to HIV status and disease progression. The Multicenter AIDS Cohort Study.

While patterns of health care financing for HIV have received considerable attention in the literature, the financial impact of disease on individuals living with HIV infection has been underexplored, particularly in relation to disease progression. Therefore, we sought to document changes in employment, income, and insurance coverage over time among HIV-negative, HIV-positive, and AIDS-diagnosed gay and bisexual men participating in the Multicenter AIDS Cohort Study (MACS) and to document measures of financial hardship. Persons with AIDS (PWAs) were 2.7 times more likely to lose full-time employment over a 6-month period than seronegative persons (p < 0.05), and loss of employment was strongly associated (p < 0.001) with both loss of private health insurance and loss of income. Twenty-seven percent of PWAs reported having financial difficulty meeting their basic expenses, compared with 10% of seronegative (p < 0.001), and 15% of PWAs, compared with only 9% of seronegative persons, said that, for financial reasons, they had not sought medical care that they thought they needed (p = 0.028). When 27% of PWAs in a cohort such as this report financial difficulty meeting their basic expenses, it is clear that the response of our public health and social welfare systems has not been adequate. Given that the problems experienced by most persons infected by HIV are considerably more severe than those experienced by MACS participants, the imperative for action is even greater.

Acquired Immunodeficiency Syndrome↗
PubMed1993

The effect of cannabidiol on mouse hepatic microsomal cytochrome P450-dependent anandamide metabolism.

Anandamide (arachidonylethanolamide) has been identified as a brain constituent that selectively binds to the cannabinoid receptor and possesses cannabimimetic activity. Cytochromes P450 catalyze the oxidation of arachidonic acid to several metabolites possessing very potent pharmacological activity. We examined whether P450 would also metabolize anandamide, and whether cannabidiol (a cannabinoid which inactivates several P450s) would affect this metabolism. Mouse hepatic P450s were found to metabolize anandamide to at least 10 different metabolites, four of which were characterized by mass spectrometry. Cannabidiol selectively inhibited the formation of two of these four anandamide metabolites. The significance of anandamide metabolism remains to be explored.

Amides↗