Biomedical subjects

X Zhao

Publications and source records attributed to X Zhao.

At least 397 records · Page 22Linked to original sources

PubMed1998

Histidine decarboxylase gene in the mouse uterus is regulated by progesterone and correlates with uterine differentiation for blastocyst implantation.

Cell-cell interactions between the blastocyst trophectoderm and uterine luminal epithelium are essential to the process of implantation. The factors that participate in these interactions or their mechanism of actions are poorly understood. Histamine has long been suspected as one of the factors that is involved in implantation. Histamine is formed from L-histidine by histidine decarboxylase (HDC). We examined the expression and regulation of HDC gene in the mouse uterus during early pregnancy and under steroid hormonal stimulation. Northern blot hybridization detected a 2.6-kb transcript of HDC messenger RNA (mRNA) in uterine poly(A)+ RNA samples. Maximum uterine accumulation of HDC mRNA occurred on days 3 and 4 of pregnancy, followed by marked declines on later days (days 5-8). In ovariectomized mice, uterine mRNA levels were up-regulated by an injection of progesterone (P4) by 6 h, and the levels were maintained through 24 h. In contrast, an injection of estradiol-17beta neither stimulated nor antagonized P4-induced HDC mRNA accumulation. P4-induced up-regulation was considerably abrogated by pretreatment with RU-486, a P4 receptor antagonist, suggesting involvement of P4 receptor. In situ hybridization detected HDC mRNA specifically in uterine epithelial cells but not in other cell types. Again, high epithelial accumulation occurred on day 4 of pregnancy. With the progression of implantation (days 5-8), HDC mRNA levels declined in the luminal epithelium surrounding the implanting blastocysts, as compared with that away from the blastocysts. Immunoreactive histamine and HDC were colocalized with HDC mRNA. Western blotting detected a 54-kDa protein in epithelial cell extracts, which also exhibited HDC activity. Expression of HDC in epithelial cells, preceding implantation on day 4, at lower levels after initiation of implantation on day 5, and its regulation by P4 suggest that this gene plays an important role in implantation.

Animals↗

PubMed1998

Involvement of insulin-like growth factor-1 and its binding proteins in proliferation and differentiation of murine bone marrow-derived macrophage precursors.

Insulin-like growth factor 1 (IGF-1) and its binding proteins (IGFBPs) are involved in proliferation and differentiation of many cell types. In the present study, the involvement of IGF-1 and IGFBPs in proliferation and differentiation of murine bone marrow-derived macrophages (BMDM) was investigated. L929-conditioned media (LCM) containing abundant macrophage colony-stimulating factor CSF-1 were used to stimulate BMDM development from their bone marrow precursors. The alteration of IGF-1 and IGFBPs during LCM-induced BMDM proliferation and differentiation was first studied. The cells were cultured in RPMI complete media containing 20% LCM for different time periods and then incubated in serum-free media for 24 h. The supernatants were collected for Western ligand blotting and immunoblotting analyses, and the cell pellets for Northern blotting analyses. The mRNA level of IGF-1 increased in a time-dependent manner. An increase of IGFBP-4 accumulation in the conditioned media was also observed during this process. However the mRNA expression of IGFBP-4 remained constant, indicating a posttranscriptional regulation of IGFBP-4 secretion and/or stability. The effects of exogenous recombinant human IGF-1 (rhIGF-1) on BMDM proliferation and differentiation were further studied. Two IGF-1 analogs (long R3 IGF-1 and des [1-3] IGF-1) were also used in parallel with regular IGF-1 to indicate the involvement of IGFBPs in BMDM development. Cells were cultured in complete media containing 20% LCM for different time periods, and then incubated in serum-free media in the presence of rhIGF-1 or its analogs for 24 h. These three forms of IGF-1 all potentiated the proliferation of freshly isolated BMDM precursors (d 0). rhIGF-1 and long R3 IGF-1, but not des (1-3) IGF-1, continued to stimulate the cell proliferation on d 1. The effects of these three forms of IGF-1 on BMDM differentiation were investigated using mannose receptor expression as a marker. Long R3 IGF-1 and des (1-3) IGF-1, but not rhIGF-1, enhanced BMDM differentiation on d 4. The different effects of rhIGF-1 and its analogs on BMDM differentiation suggest that the accumulation of IGFBP-4 in BMDM development might have an inhibitory effect on IGF-1 actions by sequestering free IGF-1.

Animals↗

PubMed1998

(6-4) photolyase: light-dependent repair of DNA damage.

DNA photolyase represents a phenomenal class of DNA repair enzymes in that it harvests the light energy to repair DNA lesions caused by ultraviolet light. Mother Nature evolves two types of photolyases, one specific for repairing cyclobutane pyrimidine dimers and the other for pyrimidine-(6-4)-pyrimidone photoproducts. Together, these two kinds of DNA photolesions account for the majority of ultraviolet light-induced DNA lesions. So far, the basic chemical steps of the enzyme mechanism of the two classes of photolyases appear to be very similar. Therefore, it will be very interesting to uncover the determinants of the different substrate specificity between the two photolyases. In this review, we focus on the discussion of the photolyase specific for repairing pyrimidine-(6-4)-pyrimidone photoproducts mainly because the research of the cyclobutane pyrimidine dimer photolyase has recently been reviewed quite extensively.

Animals↗

PubMed1998

Protein kinase C isozymes in skeletal muscles during the early stage of genetic and streptozocin diabetes.

This study examined the changes in PKC isozyme activity, content, and cellular distribution in rat gastrocnemius and soleus muscles prior to any evidence of neural degeneration or impaired skeletal muscle function, during the onset of streptozocin-induced (STZ) and genetic diabetes mellitus (DM). PKC activity was increased more in the particulate than in the soluble fractions of the soleus and gastrocnemius muscles obtained from rats treated with STZ and the gastrocnemius muscle obtained from BB-Wor diabetic rats (D rats). The predominant constitutive PKC isozymes in the skeletal muscles obtained from the STZ-treated and D rats were PKCalpha >> PKCepsilon > PKCdelta as determined by Western immunoblot assay. The content of each PKC isozyme did not differ between the soleus and gastrocnemius muscles of the control Sprague-Dawley rats for the STZ-treated rats and the BB Wor diabetic resistant (DR) rats. Moreover, the PKC isozyme content did not differ in the soluble fraction of D or STZ rats when compared to their corresponding control animals. PKCdelta increased more than PKCalpha or PKCepsilon in the particulate fraction of gastrocnemius and soleus muscles when obtained from either D or STZ rats. Since similar changes in skeletal muscle PKC isozyme profiles occurred independent of the duration of the diabetes and thereby the degree of nerve degeneration, insulin resistance, and the model of DM tested, we conclude that changes in skeletal muscle PKC precede the skeletal muscle myopathy of DM.

Animals↗

PubMed1998

Studies on the creatine kinase MM isoforms of normal and Duchenne muscular dystrophic patients.

OBJECTIVE: To study the changes of creatine kinase MM (CK-MM) isoforms in Duchenne muscular dystrophy (DMD) patients. METHODS: Serum samples from 49 DMD patients and 40 control subjects were collected for CK-MM isoforms measurement. CK-MM isoforms were separated within 30 minutes by electrophoresis on agarose gel with a discontinuous buffer system at constant current of 30 mA and low voltage of 200-300 V, then measured by fluorescence scanning. RESULTS: Significant differences of MM2/MM1 ratio were found between DMD patients and control subjects (P < 0.05) as well as among the three different age groups of DMD patients (P < 0.05). CONCLUSIONS: CK-MM isoforms may present useful information for the early diagnosis and evaluation of DMD and the ratio of MM2/MM1 can be considered as a specific indicator of the degree of seriousness for DMD patients.

Adolescent↗

PubMed1998

[Relationship of serum trace elements to lung cancer and its clinical application].

The levels of serum trace elements Cu, Zn, Fe, Mn and Ca were measured by PE3030 atomic absorption spectrophotometer in 300 patients with lung cancer, 50 with nonmalignant pulmonary diseases and 100 healthy subjects. In addition, these trace elements were also measured in 60 cases with lung cancer (40 remitted, 20 non-remitted) before and after treatment. Results showed that the concentrations of serum Cu, Mn and Cu/Zn ratio were significantly higher (P < 0.01) but Zn, Ca were significantly lower (P < 0.05-0.01) in lung cancer and nonmalignant pulmonary diseases than in healthy controls. Within the three groups there has no difference among profession, area and age discovered. In the remitted patients with lung cancer, the levels of serum Cu and Cu/Zn ratio were significantly lower (P < 0.01) but Zn, Ca were significantly higher (P < 0.01) after treatment. In the non-remitted group, only Cu/Zn ratio was significantly higher (P < 0.01) after treatment. Multivariable logistic regression analysis showed that the Odds Ratio (OR) of serum Ca was 0.9950 with 95% Confidence interval (CI) 0.9910-0.9990, and the OR of Cu/Zn was 7.9914 with 95% CI 3.4310-18.6134. It was suggested that Ca might play a protective vole while Cu/Zn ratio a risk factor for lung cancer. Results also showed that if the threshold of Cu/Zn ratio set at 1.10 in the healthy control group, the positive rate of Cu/Zn ratio was 68% which might be important in diagnosis and to assessing the prognosis of lung cancer.

Adult↗

PubMed1998

[Damage effects of asbestos and cigarette smoke solution on human embryo lung cell DNA].

OBJECTIVE: To study the combined damage effects of asbestos and cigarette solution on human embryo lung cell (HEL) DNA. METHODS: Unscheduled DNA synthesis (UDS) assay was used. Repair and synthesis on DNA in HEL treated with asbestos and/or cigarette smoke was studied. RESULTS: It showed that UDS in HEL could be induced by exposure to asbestos or cigarette smoke only with a significant dose-response relationship, and the amounts of [3H]-TdR incorporation in cells treated with combination of asbestos and cigarette smoke was significantly higher than their sum in cells treated with asbestos or cigarette only. CONCLUSION: There is a synergistic damage effect of asbestos and cigarette on DNA of HEL. In addition, dimethyl sulfoxide (DMSO), a scavenger of .OH, can partly inhibit [3H]-TdR incorporation caused by asbestos. And .OH plays certain role in damage to DNA of cells caused by asbestos.

Asbestos, Serpentine↗

PubMed1998

Changes of skin perfusion after photodynamic therapy for port wine stain.

OBJECTIVE: To obtain an objective assessment of the curative effectiveness of photodynamic therapy (PDT) for port wine stain (PWS), we investigate the relationship between the microvascular perfusion changes of PWS and the blanching of the lesions before and after PDT. METHODS: Twenty-four patients (18 females and 6 males with a total of 28 lesions) suffering from PWS were treated with PDT. The lesions of various extents were located on the face and neck. After intravenous injection of photosensitizer hepatoporphyrin derivative (HpD), the copper vapor laser was adopted as light source and the lesions of PWS were irradiated. The laser Doppler perfusion imager (LDI) was used to measure the microcirculatory perfusion of PWS before and after PDT and comparison with the normal skin was done. RESULTS: All the lesions showed remarkable decrease of tissue perfusion after PDT. It was shown that the mean, maximal and minimal values of tissue perfusion in the pre-treatment group were significantly higher than those in control group (P < 0.01). Six months after PDT, the mean, maximal and minimal values of perfusion with the lesions were reduced, with significant difference from pre-treatment group (P < 0.01), but no significant difference from control's. The colors of lesions were correlated with decrease of microcirculatory perfusion, which became lightened close to normal skin color without causing any scarring. CONCLUSIONS: PDT is one of the most effective modalities for PWS. The microcirculation perfusion can reflect the degrees of PWS objectively. The curative effectiveness of PDT for PWS is due to tissue microcirculation response.

Adolescent↗

PubMed1998

[Effect of various levels of vitamin K intake on bone metabolism of rat].

OBJECTIVE: To explore the effect of various levels of vitamin K intake on bone development. METHODS: Forty weanling Wistar male rats were divided into four groups. In one group, 1% sulfadiazine was added to regular diet (vitamin K 50 micrograms/kg) to induce vitamin K deficiency. In the other three groups, the vitamin K levels in diets were 50 micrograms/kg, 300 micrograms/kg, 2,550 micrograms/kg respectively. Twelve weeks later, the rats were killed and the effects of the different levels of vitamin K intake on bone development were evaluated by the parameters of calcium metabolism, bone metabolic biochemistry, and bone mineral density (BMD). RESULTS: Vitamin K did not affect the intestinal absorption of calcium. Vitamin K deficiency led to the high levels of urinary calcium and hydroxyapatite excretion, suggesting an increase of bone absorption. Different levels of dietary vitamin K significantly affect circulating osteocalcin and OCbound content. The level of serum2 osteocalcin, OCbound and BMD elevated with the increase of dietary VK levels, whereas the parameters of PTH (thrombo plastin time) were not different between all groups. CONCLUSION: Vitamin K can enhance the bone development of rat. The rat vitamin K requirement may be higher than that of the current recommendation (50 micrograms/kg).

Animals↗

PubMed1998

[Injury of femoral artery complicated with infection from injection of heroine].

Drug addiction has been one of the serious social problems. The peripheral phlebitis caused by drug injection is common, but the occurrence of pseudoaneurysm with infection of femoral artery from injection injury was rarely reported in China. From January 1995 to March 1996, six cases of injury of femoral artery with infection from heroine injection were admitted. The characteristics of the injury were described. The therapeutic measures and details of attention to be needed were discussed. It was concluded that this type of injury was different from the injury caused in agricultural, industrial or traffic accidents. The treatment of choice depended upon the type of injury.

Adult↗

PubMed1998

[Detection of interleukin-2 receptor in patients with idiopathic thrombocytopenic purpura].

Using ELISA and indirect fluorescent antibody techniques(IFAT), the serum soluble inter-leukin-2 receptor(sIL-2R) and membrane IL-2R (mIL-2R) on lymphocyte cells induced by phyto-hemagglutinin (PHA) were studied in patients with idiopathic thrombocytopenic purpura (ITP). The results showed that the level of sIL-2R increased significantly before treatment and decreased after treatment; the percentages of mIL-2R induced by PHA decreased. There was no correlation between the level of serum sIL-2R and that of mIL-2R. Our observations suggest that increased level of serum sIL-2R in ITP patients may be one of causes evoking cellular immunological abnormalities.

Adolescent↗

PubMed1998

[Survey on breakfast-eating behavior among residents in Beijing, Guangzhou and Shanghai].

A survey of breakfast-eating behavior among residents in Beijing, Guangzhou and Shanghai was carried out in 1994-1995. The results showed that the breakfast-eating rates in three cities were 74.8%-90.5%. Subjects aged below 35 years skipped breakfast more often. "Time limiting" in the morning became the main cause of breakfast-skipping. Nearly half of subjects in three cities got their breakfast out of home. Moreover, compared with two years ago, the present rates of eating outside increased at various levels in three cities. Steamed bun, bread and congee were main foods consumed at breakfast. In addition, 39% to 56% of subjects often drank milk. Through this survey, the authors got an all-round understanding on breakfast-eating rates, eating outside rates and variety of food consumed of residents in 3 cities. This survey will also provide a background for nutrition intervention and education in the future.

Adult↗

PubMed1998

[Detecting expression of the multidrug resistance gene product (P170) in human tumor tissues and cells by flow cytometry].

We have detected the human multidrug resistance gene (MDR1) product P170 in 29 solid tumor samples and K562 cell line through indirectimmunoflourence staining by flow cytometry using mouse monoclonal antibody (McAb). The results showed that the expression of P170 was detected in 18 samples, the positive ratio being 62.1%; the expression was not detected in 11 samples, the negative ratio being 37.9%; and 99.9% of K562 cells expressed P170. In 16 of the 18 positive samples, the percent ratio of tumor cells for expression of P170 was less than 30%; in the other 2, more than 30%. This indicated that the positive ratio of P170 of most tumor samples was high, but their percent ratio of P170 was low. Thus it provided a parameter for reference in evaluating the efficacy of clinical antitumor treatments.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[Prognostic value of basal hormone levels on ovarian reserve].

OBJECTIVE: To study the prognostic value of basal hormone levels on ovarian reserve during ovulation induction. METHODS: Day 2 serum follicle stimulating hormone (FSH), luteinizing hormone (LH) and estradiol (E2) levels of 112 ovulation induction cycles (60 infertile patients) were measured by radioimmunoassay. The relationship between basal hormone levels and numbers of dominant follicles and pregnancy rates were analysed. RESULTS: Day 2 serum FSH > or = 15 IU/L predicted a poor response to ovarian stimulation, with fewer dominant follicles and lower pregnancy rate, so was day 2 serum E2 > or = 45 ng/L. Day 2 serum LH level was unrelated to pregnancy rate. CONCLUSION: Day 2 FSH and E2 levels are useful in prognostic assessment of ovarian reserve.

Adult↗

PubMed1998

[Imaging manifestations of tumors metastasized in fatty liver].

OBJECTIVE: To evaluate the manifestations of tumors metastasized in fatty liver and the value of various imaging modalities, especially CT. METHODS: Nine cases of tumors metastasized in fatty liver were proved by clinical follow-up for 3-13 months. The primary neoplasms were breast carcinoma in 6 cases; ovarian carcinoma, malignant melanoma and colon carcinoma, one case for each. All had CT(19 episodes) and ultrasonography (US, 20 episodes). Four cases had MRI and 2 cases had DSA. RESULTS: Liver metastatic lesions were missed by US in 2 cases with moderate to marked fatty liver. On CT without contrast administrations, fatty liver was divided into marked, moderate and mild degree according to the density of hepatic parenchyma which was lower than that of the spleen; lower and higher than or equal to that of the intrahepatic blood vessels. Depending on the degree of fat infiltration(FI), the density of the metastatic lesions was high when FI was marked and low when FI was mild. However, when FI was moderate, the density of the metastatic lesions varied, being high, equal or low. On enhanced CT, all of the lesions were enhanced with moderate to marked fatty liver background. Lesions were heterogeneous in 4 cases. On plain CT, metastatic lesions had high-density rim, 2-6 mm in width in 4 cases. In SE sequence of MRI, metastatic lesions were hypointense on T1W and hyperintense on T2W, and moderately hyperintense on opposed-phase. CONCLUSION: Tumors metastasized in fatty liver show a broad spectrum of image manifestations. They are related to the degree of fat infiltration. On plain CT, isodense lesions are easily escaped detection when moderate degree of fatty liver is present. Contrast administrations is mandatory. Liver metastases is suggested if a lesion is found with hyperattenuating rim on plain CT, or appears heterogeneous after enhancement. MRI is of diagnostic help.

Adult↗

PubMed1998

[Clinical study of childhood acute myelogenous leukemia].

OBJECTIVE: To investigate the clinical characteristics, treatment responsiveness and prognostic factors of childhood acute myelogenous leukemia. METHODS: Two hundred and seventy-four children with acute myelogenous leukemia diagnosed between 1978 and 1995 were retrospectively analyzed. RESULTS AND CONCLUSIONS: Male:female is 1.6:1. The median age was 7.25 years. M2 and M3 were the commonest subtypes(80%). Twenty cases were hyperleukocytosis and 24 with extramedullary involvement. Thirty two percent of the patients was Auer rods positive. Two hundred and forty-four patients received combination chemotherapy. Complete remission (CR) rates varied from 55.88% to 92.31%. Intensive chemotherapy(including DA, DA + Vm26 or Vp16) was the cornerstone for high CR rate. Other factors influencing CR rate were initial WBC count and hepatosplenomegaly.

Adolescent↗

PubMed1998

[Observation of enalapril on treating the patients with left ventricular diastolic dysfunction].

The effects of enalapril on 50 patients with left ventricular diastolic dysfunction (LVDD), confirmed by clinical features and radionuclid ventriculography, were assessed in a randomized, double-blind, and controlled method for eight weeks. The results showed that left atrial diameters (LAD), interventricular septum thicknesses (IVST) and left ventricular mass indexes (LV-MI) except left ventricular diameters (LVD) were decreased in the enalapril treatment group. The left ventricular diastolic function parameters such as the early peak filling velocity (EPAV), the atrial peak filling velocity (APAV), the deceleration of early peak filling velocity (DC) and the isovolumic relaxation time (IRT) were improved, the NYHA class and the exercise tolerance were increased, the left ventricular ejection fraction (LVEF), and the cardiac index (CI) were not altered in the enalapril treatment group. The patients with LVDD were well tolerated with enalapril. The parameters mentioned above were not altered in control group. It is suggested that enalapril is an effective drug in the treatment of LVDD.

Adult↗

PubMed1998

[Retinoic acid inducing Fas expression in HL-60 cells].

OBJECTIVE: To investigate the effect of all-trans retinoic acid (ATRA) and 9-cis retinoic acid (9-cis RA) on the expression of Fas and the sensitivity to anti-Fas induced apoptosis in HL-60 cells. METHODS: Fas expression was detected by flow cytometry. Anti-Fas induced apoptosis (AFIA) was determined by morphological features, DNA fragment electrophoresis, and flow cytometric cell cycle analysis. RESULTS: Fas antigen was weakly expressed on HL-60 cells. After incubation of HL-60 cells with 10(-6) mol/L ATRA or 9-cis RA for 4 days, both the Fas expression and AFIA were significantly enhanced. 9-cis RA was more potent than ATRA in increasing the sensitivity to AFIA. CONCLUSION: RA might upregulate Fas expression. Further elucidation of its molecular mechanisms might provide a rationale for new therapeutic strategies of malignant diseases.

Antineoplastic Agents↗