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J T Liu

Publications and source records attributed to J T Liu.

31 records · Page 2Linked to original sources
PubMed1995

Analysis of induced sputum after air and ozone exposures in healthy subjects.

Exposure of healthy subjects to ozone is associated with increases in cellular and biochemical markers of inflammation in bronchoalveolar lavage fluid. To determine if analysis of induced sputum might similarly reveal the pulmonary inflammatory effects of ozone exposure, we performed cellular and biochemical analysis of induced sputum collected 4 hr after air and ozone (0.4 ppm for 2 hr) exposures from 10 healthy subjects (age 30.0 +/- 5.0 years; 5 females) in a randomized crossover study in which exposures were separated by 2 weeks. We found that the total number of nonsquamous cells was significantly higher after ozone exposure than after air exposure (7.4 vs 3.9 x 10(5)/ml, P < 0.05) as was the percentage of the nonsquamous cells that were neutrophils (80.0 +/- 7.0% vs 51.0 +/- 20.0%, P < 0.05) and the levels of myeloperoxidase in the sputum fluid phase (1.6 +/- 0.6 vs 1.3 +/- 0.6 microg/ml, P < 0.05). In addition, IL-6 and IL-8 levels were higher after ozone than after air exposures, but not significantly so (44.5 +/- 32.4 pg/ml vs 26.8 +/- 30.7 pg/ml, P = 0.11; 1.5 +/- 0.5 ng/ml vs 1.1 +/- 0.6 ng/ml, P = 0.09). Mucin-like glycoprotein levels were also not significantly different between exposures (1.6 +/- 0.9 mg/ml vs 1.3 +/- 1.0 mg/ml, P = 0.26). We conclude that analysis of induced sputum is a useful noninvasive method for studying the pulmonary response to ozone exposure in healthy subjects.

Adult↗
PubMed1994

Thrombin inhibitors and anti-coagulants on thrombin-induced embolisation in rabbit cranial vasculature.

111Indium-labelled platelets were continuously monitored in the cranial vasculature of anaesthetised rabbits and thrombin inhibitors and anti-coagulants were tested on the sustained platelet accumulation induced by intracarotid injection of thrombin (90 U/kg). Pretreatment, commencing 30 min prior to thrombin, with a 1-h intracarotid infusion of D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (PPACK; 0.25-1.0 micrograms/kg per min), unfractionated heparin (Multiparin; 5-20 U/kg bolus + 0.75-3.0 U/kg per min infusion) or low molecular weight heparin (Fragmin; 2.4-9.6 U/kg per min) produced dose-related reductions in platelet accumulation. Continuous infusion of acetyl-D-phenylalanyl-prolyl-boroarginine (DuP-714 ester; 30 micrograms/kg per min) for 30 min induced marked accumulation of platelets in the pulmonary circulation in the absence of thrombin. Bolus intracarotid injection, 1 min before thrombin, of Hirulog (0.05-0.2 mg/kg), PPACK (10-30 micrograms/kg), Multiparin (25-100 U/kg), Fragmin (150 U/kg) or DuP-714 ester (15-30 micrograms/kg) caused significant reductions in platelet accumulation. When injected 1 min after thrombin, Hirulog (1 mg/kg), PPACK (100 micrograms/kg), Fragmin (150 U/kg) and DuP-714 ester (30 micrograms/kg) had no significant effect and Multiparin (100 U/kg) increased platelet accumulation. The results demonstrate that pretreatment with a range of thrombin inactivators, acting via different mechanisms, can inhibit thrombin-induced cerebral thromboembolism in the rabbit.

Amino Acid Chloromethyl Ketones↗
PubMed1993

Protection of bone-marrow granulocyte-macrophage colony-forming units in mice bearing in vivo alkylating-agent-resistant EMT-6 tumors.

The survival of bone-marrow granulocyte-macrophage colony-forming units (CFU-GM), an alkylating-agent-sensitive normal tissue, was assessed in mice bearing the EMT-6 parental tumor or the in vivo resistant EMT-6/CDDP, EMT-6/CTX, EMT-6/Thio, and EMT-6/Carbo tumors. The survival pattern of the bone-marrow CFU-GM recapitulated the survival of the tumor cells, mimicking the development of resistance and reversion to sensitivity upon removal of the selection pressure for each of the four alkylating agents. When the EMT-6 parental tumor was implanted in the opposite hind limb of animals bearing the EMT-6/CDDP or EMT-6/CTX tumor, the survival of the parental tumor cells after treatment of the animals with the appropriate antitumor alkylating agent was enhanced. The EMT-6/CDDP tumor was cross-resistant to CTX and high-dose L-PAM, whereas the EMT-6/CTX tumor was somewhat resistant to CDDP and markedly sensitive to VP-16. In each case, the survival pattern of the bone-marrow CFU-GM reflected the survival of the tumor cells. These results indicate that the presence of an alkylating-agent-resistant tumor in an animal can affect the drug response of tissues distal to that tumor.

Alkylating Agents↗
PubMed1993

[Protective effects of 3, 6-dimethamidodibenzopyriodinium citrate on myocardial injury induced by ischemia and reperfusion in rats].

3, 6-Dimethamidodibenzopyriodonium citrate (I-65) 0.5 and 1 mg.kg-1 pretreatment reduced the size of myocardial infarct after ischemia for 40 min and reperfusion for 120 min. I-65 0.5 mg.kg-1 decreased myocardial creatine kinase, lactate dehydrogenase release, and Ca2+ accumulation after ischemia for 40 min and reperfusion for 120 min. The results show that I-65 prevents cardiac ischemia and reperfusion injury and the effect is considered to be related to inhibition of myocardial Ca2+ accumulation.

Animals↗
PubMed1993

Differential distribution of glycoconjugates in human reproductive tract.

OBJECTIVES: To study the distribution of glycoconjugates in the epithelia of various regions of the human female reproductive tract and to examine whether lectins can be used as specific probes to define cell populations in the human female reproductive tract. DESIGN: Nineteen fluorescein isothiocyanate (FITC)-labeled lectins, which recognize different oligosaccharide structures, were applied to frozen sections of human fallopian tubes (distal and proximal segments) and endometrium. The differential binding patterns of the lectins to the epithelia were evaluated under fluorescent microscopy. RESULTS: Four of 19 FITC-labeled lectins tested demonstrated distinct binding patterns along the reproductive tract. Arachis hypogaea (PNA) and Ricincus communis II selectively reacted with epithelial cells of endometrium and distal, but not proximal tube. In addition, PNA distinguished ciliated from secretory cells of the distal tube. Maclura pomifera binding followed a gradient of decreasing intensity from distal to proximal tube and was negative in the endometrium. Dolichos biflorus reacted exclusively with proximal tubal epithelium. CONCLUSIONS: Analysis of the FITC-lectin binding pattern and the sugar specificities indicate that the distribution of galactosyl residues varies among different regions of the reproductive tract, whereas glucosyl, mannosyl and fucosyl residues are more evenly distributed. The differential expression of glycoconjugates may be involved in the distinct biological function of each region in female reproductive tract.

Endometrium↗
PubMed1992

[Intracellular bile acid activities in colon cancer and normal colon mucosa].

Bile acids are thought to be involved in the etiology and development of colo-rectal cancers. In this study, the intracellular bile acid activities both in colo-rectal cancers and normal colo-rectal mucosa in 12 patients were measured with a new bile acid ion selective microelectrodes. The results demonstrated that bile acid activities of colo-rectal mucosa cells were 5.0 +/- 3.7 x 10(-5) mol/L and those in colo-rectal cancer cells were 17.6 +/- 9.6 x 10(-5) mol/L, which is three times as high. This demonstrates that bile acids are closely related to the development of colo-rectal cancers. The intracellular bile acid activities remain stationary with age and sex.

Adult↗
PubMed1991

[Expression of human lymphotoxin gene in CHO-DHFR- cells].

A recombinant plasmid p91-HuLT was constructed with a human lymphotoxin (HuLT) gene 2.4 kb EcoRI fragment and a mammalian cell expression vector plasmid p91023. The HuLT EcoRI DNA fragment covers entire coding sequence and some 3(1) non-translated region sequence of the gene, p91-HuLT DNA was used to transfect Chinese hamster cell line CHO-DHFR- cells by using calcium phosphate-DNA coprecipitation method, and DHFR+ transfectants were obtained. RNA dot blot hybridization analysis showed that the HuLT mRNA was produced by p91-HuLT in transfectants. The results of MTT dye reduction assay indicated that the DHFR+ cell lines we obtained constitutively synthesize and secrete the HuLT with the cytotoxic activity of at least 200 units per mL of medium.

Animals↗
PubMedDate not supplied

A carbonic anhydrase inhibitor as a potential modulator of cancer therapies.

Since several anticancer drugs are known to become more cytotoxic to cells in an acidic milieu, we have attempted to utilize the carbonic anhydrase inhibitor, Acetazolamide, to acidify the blood and tumor of C3H mice bearing the FSaIIC fibrosarcoma in order to sensitize tumor cells in vivo to CDDP, Melphalan, BCNU, SR4233 or PtCl4 (Fast Black)2 +/- hyperthermia. The direct cytotoxic interactions between the anticancer drugs and Acetazolamide were tested in FSaIIC cells in vitro with the monacidifying diuretic Chlorothrozide as a control. When cells were exposed to CDDP both diuretics protected against cytotoxicity in a dose dependent fashion. In contrast, cells exposed to Melphalan were minimally sensitized and those exposed to BCNU, SR4233, or PtCl4 (Fast Black)2 were essentially unaffected by the presence of the diuretic agents. Both diuretics were essentially non-toxic to cells in vitro, and, interestingly, both drugs markedly protected cells against hyperthermia under low pH conditions. In vitro, however, Acetzolamide produced a tumor growth delay of 2.3 days alone when given at 10 mg/kg i.p. once (the most effective dose) and produced additive growth delays with CDDP and Melphalan, but probably greater than additive delays with SR4233 and PtCl4 (Fast Black)2. When Acetazolamide was given daily for 5 days starting on the day the anticancer drugs were given once (day 7) essentially no further increase in tumor growth delay of nearly 16 days was observed versus only 4,6 days for the drug alone. When hyperthermia (43 degrees C min.) was delivered locally to the tumor after i.p. injection of the drugs, further growth delays were produced for every drug combination which probably were additive in extent. Blood and urine pH determinations revealed that a pH drop of 1 units occurred in the blood and a pH elevation of 1 to 21 units occurred in the urine 1 hr. after i.p. injection of Acetazolamide. These results indicate that this carbonic anhydrase inhibitor can add to the anticancer activity of the drugs tested. The mechanism may involve its ability to acidify the intratumoral environment, but other mechanisms can not be excluded.

Acetazolamide↗