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Biomedical subjects

X Hu

Publications and source records attributed to X Hu.

At least 325 records · Page 18Linked to original sources
PubMed1997

[Pharmacognostic studies of Tibetan medicine da-li].

Da-Li is a traditional medicine of Tibetan, its original plant is Rhododendron primulaeflorum Bur. et Franch and R. anthopogonoides Maxim. This paper reports the identification of Flos et Folium Rhododendri Primulaeflori on its macroscopic character, microscopical charactersitic and TLC. The comparison between the Flos et Folium Rhododendri Primulaeflori and Flos et Folium Rhododendri anthopogonoidi is also reported.

Chromatography, Thin Layer↗
PubMed1997

[Determination of liensinine in plasma by high performance liquid chromatography].

A sensitive method of high performance liquid chromatography (HPLC) for determination of liensinine in plasma is reported. An Ultrasphere Si column, 250 mm x 4.6 mm i.d. with dichloromethaneisopropyl alcohol-diethylamine (75:25:0.2, V/V) as mobile phase at a flow-rate of 1.0 mL/min and UV-detector at 282 nm were used. Neferine was served as the internal standard. Liensinine in plasma was extracted with diethyl ether three times after adding ammonia-ammonium chloride buffer (pH 10). Liensinine was completely separated from nefrine. The retention times of liensinine and neferine were 8.5 and 5.0 minutes, respectively. The calibration line of liensinine was linear in the range of 0.0625-5.0 mg/L (r = 0.9996). The mean recovery was 93.6% with RSD of 1.9%. The precision of intra-day and inter-day for liensinine was in the range of 1.4%-4.1% and the detectable limit was 0.025 mg/L based on a signal-to-noise ratio of 3. The results showed that the method was simple and sensitive.

Chromatography, High Pressure Liquid↗
PubMed1997

[Study on the tribochemistry of antiwear additive BA1 by FTIRM].

This paper studied the tribochemistry of antiwear additive BA1 by FTIR microscope technique. We observed the changes of physical properties, interpreted the infrared spectra of the products in the track and concluded the chemical mechanism through the change of BA1 concentration, load and rubbing time. The results shows that the BA1 was decomposed, oxided and a thin film was produced when rubbed. This film makes the rubbing efficiency less.

English Abstract↗
PubMed1997

[Study on self-activation of phosphorylated amino acids to form peptides by FTIR].

The self-activation of six phosphorylated amino acids to form peptides was studied in i-propyl alcohol by FTIR. The results indicated that the phosphorylated amino acids could be self-activated to form peptides in alcohol and the FTIR method in the study on the self-activation of phosphorylated amino acids to form peptides can provide useful information for life process.

2-Propanol↗
PubMed1997

[TR-FTIRS study of crystal phase transformation in polyvinylidene fluoride].

The study of polyvinylidene fluoride (PVDF) by time-resolved Fourier transform infrared spectroscopy (TR-FTIRS) was reported. The instantaneous change and process of both alpha-form and beta-form during transformation were studied under the pulse electric field excitation. Transformation of alpha-form to beta-form was indicated by the increasing of the peak at 508cm(-1), the decreasing of the peak at 528cm(-1) and a shift of those peaks. The transient change time was about 5ms. The decreasing of the peak at 528cm(-1) was nonlinear. A hysteresis-like loop was observed, which was related with the biaxially orientated property of PVDF and was in good agreement with its polarizated hysteresis loop.

English Abstract↗
PubMed1997

[Determination of six trace elements in steels by ICP-AES with the changed internal standard].

This paper studies the direct determination of P, Si, Mn, Cu, Cr and Ni in steels with the changed internal standard. The standard curves are standardized with FULL STANDARDIZATION, and the results of the sample are calibrated with TYPE STANDARD in time. The signal intensity influenced by RF power, observation height and sample gas folw is discussed. Results obtained for the determination of every element in steels are satisfactory. The RSD is less than 0.5% and the recovery is about 96-103%. The detection limit is about 0. 002-0.07%.

English Abstract↗
PubMed1997

[Elimination of nitrogen dioxide and nitric oxide by soda lime and its components].

OBJECTIVES: To investigated the efficacy of soda lime and its components in absorbing NO2 and NO. METHODS: VIP BIRD ventilator was connected with Siemens test lung. While the concentration of inhaled NO was 80 mg/L, the inspired gas passed through soda lime or its component. NO and NO2 were measured before and after testing materials in the circuit. Test 1, the soda lime canister sequentially was filled with smaller particle soda lime 500, 250, 125, 62.5, 39, 20, 10 and 0 g, to determine weight-efficacy relationship of the soda lime. Test 2, the canister sequentially was filled with bigger particle soda lime 500, 62.5, 30, 20 and 10 g, for comparing effective absorption of NO and NO2 between the two types of soda lime Test 3, 1.0 g methyl orange was added to smaller particle soda lime 10 g and 20 g respectively to observe its effect on eliminating NO and NO2. Test 4, silica gel tube was filled with smaller particle soda lime 10 g, KOH 10 g, NaOH 10 g, Ca(OH)2 2.5 g, and methly orange 0.5 g respectively for observing their ability of eliminating NO and NO2. RESULTS: The two types soda lime had the ability to eliminating NO and NO2 from inspired gas with a positive relationship with its weight. Both KOH and NaOH did not eliminate NO and NO2 Ca(OH)2 and methyl orange had a week ability. Methyl orange did not affect the ability of soda lime to eliminate NO2, but decreased its ability to eliminate NO. During 240 min, the eliminating NO2 ability of soda lime did not change, but the eliminating NO ability was reduced from 30% to 19% after 60 min. CONCLUSIONS: The effective components to eliminate NO and NO2 in soda lime are Ca(OH)2 and NaOH. Their ability to eliminate NO and NO2 increases with increase in their weight. The ability to eliminate NO decreases with increase in the contacting time with NO.

Calcium Compounds↗
PubMed1997

[The amounts of inositol 1,4,5-triphosphate and it response to epidermal growth factor and laminin of carcinoma substrains with high or low metastatic potentials].

OBJECTIVE: To examine the IP3 amounts, invasive potentials, and response to LN and EGF of the substrains with high or low metastatic ability from two kinds of carcinoma cell lines (MFC and CNZ-2Z). METHOD: Radio-ligand binding assay and matrigel invasive assay. RESULTS: The low metastatic substrains from the two lines had higher amounts of IP3 and stronger response to EGF than their responsive high ones, but high metastatic substrains from CNZ-2Z had stronger response to LN than the low ones while MFC substrains had not significant difference in response to LN. CONCLUSION: There is internal difference in signal transduction between the high and low metastatic cancer cells, and it is significant to study the difference in detail.

Animals↗
PubMed1997

Combination therapy with 5-fluorouracil and IFN-alpha2a induces a nonrandom increase in DNA fragments of less than 3 megabases in HT29 colon carcinoma cells.

We have used pulsed-field gel electrophoresis to examine 5-fluorouracil (5FU)-induced DNA double-strand breaks (DSBs), both with and without modulation by IFN-alpha2a (IFNalpha), in HT29 human colon adenocarcinoma cells. Although 24-h treatment with either 10 microM 5FU or 500 units/ml IFNalpha did not result in significant DNA fragmentation, the combination of 5FU + IFNalpha resulted in a significant increase in DNA DSBs versus either drug alone (P < 0.05). The pattern of fragmentation induced by treatment with 5FU + IFNalpha was compared to that induced by gamma-radiation, which generates lesions at random sites, digestion with NotI restriction endonuclease, which cleaves at the specific sequence 5' ellipsis GCGGCCGCellipsis 3', and HhaI restriction endonuclease, which cleaves at the specific sequence 5'ellipsis GCGCellipsis 3'. 5FU + IFNalpha resulted in a specific pattern characterized by the accumulation of fragments of <3 Mb in the absence of fragments of >3 Mb, which differed from that of gamma-radiation and restriction endonuclease digestion. Because neither morphological nor DNA fragmentation characteristic of apoptosis was observed after 5FU + IFNalpha treatment, the nonrandom pattern of DSBs that was observed did not appear to be the result of the initiation of programmed cell death within these cells.

Apoptosis↗
PubMed1997

[Clinical application of biological bone carrier in repair of long bone defect of femur].

It is difficult to repair long defect of bone. Biological bone carrier (BBC) was one of the artifical bone substitutes. It was obtained from human or swine bone after a series of biochemical treatment. It had good histocompatibility. It had the same components and structure of bone, and its biological strength was samiliar to bone. In clinic, BBC was applied to repair of long defect of bone in two cases. The lengths of defect were 13 cm and 11 cm, respectively. After followed up for 2 to 3 years, it was found that the implanted BBC had been combined with the femur with new bone. It had the same metabolism and density as that of the normal bone.

Adolescent↗
PubMed1996

An alpha class mouse glutathione S-transferase with exceptional catalytic efficiency in the conjugation of glutathione with 7beta, 8alpha-dihydroxy-9alpha,10alpha-oxy-7,8,9,10-tetrahydrobenzo(a)pyrene.

The kinetics of the conjugation of glutathione (GSH) with anti-7beta, 8alpha-dihydroxy-9alpha,10alpha-oxy-7,8,9, 10-tetrahydrobenzo(a)pyrene (anti-BPDE) catalyzed by GSH S-transferase (GST) isoenzymes purified from the liver and forestomach of female A/J mouse has been investigated. The GST isoenzymes studied included an alpha class isoenzyme of forestomach (GST 9.5), alpha class hepatic isoenzymes mGSTA3-3 and mGSTA4-4, pi class hepatic isoenzyme mGSTP1-1, and mu class hepatic isoenzyme mGSTM1-1. When the concentration of (+)-anti-BPDE was varied (5-120 microM) at a fixed GSH concentration (2 mM), linear Lineweaver-Burk plots were observed for each isoenzyme. The kcat values for GST 9.5, mGSTA3-3, mGSTP1-1, mGSTM1-1, and mGSTA4-4 were 2.0, 0.02, 0.40, 0. 05, and 0.01 s-1, respectively, with corresponding Km values of 16, 12, 29, 27, and 49 microM. The catalytic efficiency (kcat/Km) of GST 9.5 in the conjugation of GSH with (+)-anti-BPDE, which is believed to be the ultimate carcinogenic metabolite of benzo(a)pyrene, was about 9-625-fold higher as compared with other mouse GST isoenzymes. These results indicate that GST 9.5 of forestomach is different among mammalian alpha class GSTs because (+)-anti-BPDE has been shown to be a poor substrate for alpha class rat or human GST isoenzymes. The catalytic efficiency of GST 9.5 was approximately 4.5-fold higher than that of pi class human isoenzyme (hGSTP1-1), which among human GSTs is reported to be most efficient in the detoxification of (+)-anti-BPDE. Unlike rat GST isoenzymes, linear Lineweaver-Burk plots were observed for mouse GSTs when GSH was used as a variable substrate. The catalytic efficiencies of the mouse GSTs toward (+)-anti-BPDE were about 2-20-fold higher as compared with the (-)-enantiomer of anti-BPDE. The results of the present study suggest that GST 9.5 may play an important role in the detoxification of (+)-anti-BPDE.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1996

Glutathione S-transferases of female A/J mouse liver and forestomach and their differential induction by anti-carcinogenic organosulfides from garlic.

This study characterizes glutathione (GSH) S-transferase (GST) isoenzymes of the liver and forestomach of the female A/J mouse and compares their specificities in catalyzing the conjugation of GSH with 7beta,8alpha-dihydroxy-9alpha,10alpha-oxy-7,8,9, 10-tetrahydrobenzo[a] pyrene (anti-BPDE), the ultimate carcinogenic metabolite of benzo[a]pyrene (BP). The GST activity in female A/J mouse liver was expressed by a minimum of seven isoenzymes which arose from different homo- or heterodimeric combinations of at least two alpha class (designated as alpha1 and alpha4), four micro class (micro1 to micro4), and one pi class GST subunit. The GST isoenzyme composition of A/J mouse forestomach appeared to be different from that of the liver. For example, while GST isoenzymes containing micro3 and micro4 type subunits were selectively expressed in the liver, an alpha class heterodimeric GST isoenzyme (containing alpha2 and alpha3 subunits) was expressed in the forestomach but could not be detected in the liver. The (+)-anti-BPDE appeared to be a better substrate than the (-)-enantiomer for all GSTs, except for isoenzymes containing the alpha4 type GST subunit. The murine pi class GST isoenzyme displayed relativey higher specific activity toward (+)-anti-BPDE compared to other GSTs. The specific activities of mouse GSTs toward (+)-anti-BPDE were in the order of pi > micro > alpha. These results suggest that the pi class GST isoenzyme may play an important role in providing protection against BP-induced cancer. Therefore, it seems logical to postulate that the ability of a chemoprotector to increase the expression of GST pi may be an important determinant of its effectiveness against BP-induced cancer. To test the validity of this contention, we have determined the effects on hepatic and forestomach GST isoenzyme/subunit expression of three naturally occurring organosulfides (OSCs) from garlic, which significantly differ in their effectiveness against BP-induced forestomach cancer. Treatment of mice with diallyl sulfide (DAS) and diallyl trisulfide (DATS), which are potent inhibitors of BP-induced fore- stomach cancer in mice, resulted in a significant increase in hepatic and forestomach GST activity toward anti-BPDE. On the contrary, this activity was not increased in either organ by dipropyl sulfide (DPS), which is ineffective against BP-induced forestomach cancer. The chemopreventive efficacy of these OSCs correlated with their ability to increase the expression of GST pi. For example, DAS treatment resulted in approximate increases of 1.7- and 2.2-fold in hepatic and forestomach GST pi expression, respectively, over the control. Treatment of mice with DATS, which is a relatively more potent inhibitor of BP-induced forestomach cancer than DAS, resulted in about 3.8- and 3.2-fold increases, respectively, in hepatic and forestomach GST pi expression over the control. On the contrary, the expression of hepatic and forestomach GST pi was increased only marginally (10-20%) upon DPS administration. In conclusion, the results of the present study suggest that induction of GST pi can be used as a bioassay for screening potential inhibitors of BP-induced cancer.

7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide↗
PubMed1996

Multiple early gastric carcinomas. Clinicopathologic features and histogenesis.

BACKGROUND: Multiple early gastric carcinomas were found in 5-15% of patients with early gastric carcinoma. The goals of this study were to clarify the clinicopathologic features of multiple early gastric carcinomas and to investigate their histogenesis. METHODS: Of 724 patients with early gastric carcinoma, there were 65 with multiple (159) gastric carcinomas. Investigation of the histogenesis of multiple gastric carcinomas was conducted using serial sections of the stomach of 33 patients with multiple early gastric carcinomas (MEGC) and 33 patients with solitary early gastric carcinoma (SEGC). The cancerous and epithelial dysplastic lesions were examined by hematoxylin and eosin staining and immunohistochemical staining of p53 protein with anti-p53 monoclonal antibody (BP53-12). RESULTS: The macroscopically depressed type was common. The flat type was observed only in accessory lesions, most of which were diagnosed postoperatively. There were 126 differentiated type lesions, and 33 poorly differentiated type lesions. In most cases both the main and accessory lesions were differentiated. The average number of epithelial dysplastic lesions (18.3) in the stomach of patients with differentiated MEGC was significantly higher than that in the stomach of patients with differentiated SEGC (7), poorly differentiated MEGC (2.1), and SEGC (2). Moreover, severe dysplastic lesions were frequently observed in the stomach of patients with differentiated MEGC. p53 protein expression was detected in 0.9% of mildly atypical epithelial dysplastic lesions, 3.7% of moderately atypical dysplastic lesions, and 18.2% of severely dysplastic lesions. CONCLUSIONS: In cases of early gastric carcinoma, small depressed type and flat type accessory lesions of multiple gastric carcinomas should be detected preoperatively. Epithelial dysplastic lesions probably are significant in the histogenesis of differentiated multiple gastric carcinomas.

Adenocarcinoma↗
PubMed1996

The human diploid fibroblast senescence pathway is independent of interleukin-1 alpha mRNA levels and tyrosine phosphorylation of FGFR-1 substrates.

In vitro cellular senescence of human umbilical vein endothelial cells (HUVEC) may involve the intracellular activity of the signal peptide-less cytokine interleukin (IL)-1 alpha. To determine whether senescence of other human diploid cells involves the function of IL-1 alpha, we examined the steady-state expression of IL-1 alpha mRNA in IMR-90 fibroblasts. The IL-1 alpha transcript was not elevated in senescent IMR-90 cells. With the exception of the plasminogen activator inhibitor (PAI)-1 transcript, other IL-1 alpha-response gene mRNAs were not induced in senescent IMR-90, although the mRNA for each gene was induced by exogenous IL-1 alpha. The mRNA expression of cell cycle-specific genes demonstrated that Fos and ornithine decarboxylase (ODC) were induced in young and senescent cells in response to both serum and fibroblast growth factor (FGF)-1. Histone (H)3 mRNA was induced by serum in young cells, but not in senescent cells, and FGF-1 failed to induce H3 mRNA in either young or senescent cells. Further, while young IMR-90 populations were able to respond to serum as an initiator of DNA synthesis and cell growth, they did not exhibit a response to exogenous FGF-1. FGF receptor (R)-1 substrates were not tyrosine phosphorylated in either young or senescent IMR-90 cells. These data demonstrate that IL-1 alpha and FGF-1 may have different functions in HUVEC and IMR-90 fibroblast populations including distinct pathways for the regulation of cellular growth and senescence.

Cellular Senescence↗
PubMed1996

Nanosecond step-scan FTIR spectroscopy of hemoglobin: ligand recombination and protein conformational changes.

Step-scan FTIR spectroscopy with nanosecond time resolution is applied to the photocycle of carbonmonoxy hemoglobin (HbCO). The strong CO stretching band at 1951 cm-1 serves as a convenient monitor of the state of ligation. Both geminate and second-order phases of CO recombination occur at rates which are in excellent agreement with previous visible absorption measurements, showing the molecular mechanisms to be unperturbed by the high protein concentrations (6.7 mM in heme) required for adequate protein signals. While the extent of photolysis (43%) was insufficient to drive the R-->T quaternary transition, the protein TRIR (time-resolved infrared) difference bands (1250-1700 cm-1) nevertheless reveal interesting tertiary dynamics. Most of the bands are fully developed at very early times, possibly preceding the geminate recombination phase (tau = 50 ns). Some bands arise more slowly, however, with a time constant of 0.4 microsecond, reflecting a tertiary motion which is coincident with a quaternary motion previously detected by ultraviolet resonance Raman spectroscopy of fully photolyzed HbCO. Relaxation of the TRIR bands is either faster (tau = approximately 90 microseconds) or slower (tau = approximately 250 microseconds) than CO rebinding (effective time constant of 160 microseconds), suggesting either a distribution of tertiary processes or a chain inequivalence in CO rebinding.

Carbon Monoxide↗