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S F Liu

Publications and source records attributed to S F Liu.

At least 73 records · Page 4Linked to original sources
PubMed1989

Evidence for two P2-purinoceptor subtypes in human small pulmonary arteries.

1. P2-purinoceptors have not been characterized in human pulmonary vessels and we therefore examined the effects of adenosine 5'-triphosphate (ATP) and its analogues on human isolated small pulmonary arteries (SPA) in vitro. 2. Contractile responses were induced by all of the analogues, with the rank order of potency alpha,beta-methylene-ATP (alpha,beta-meATP) = beta,gamma-methylene-ATP (beta,gamma-meATP) greater than ATP greater than 2-methylthio-ATP, indicating the presence of vasoconstrictor P2x receptors. 3. In precontracted SPA, vasodilator responses were produced by all of the analogues. The rank order of potency for the analogues causing vasodilator responses was: 2-methylthio-ATP much greater than ATP much greater than beta,gamma-meATP = alpha,beta-meATP, indicating a vasodilator P2y receptor. 4. Removal of endothelial cells had no significant effect on either the contractile or relaxant responses to any of the analogues. 5. After pretreatment of the endothelium-denuded vessels with alpha,beta-meATP (to desensitize P2x receptors), the contractile response to beta,gamma-meATP (a potent P2x receptor agonist) was abolished. 6. We conclude that both P2x- and P2y-purinoceptors are present in human SPA and that both receptors reside on the vascular smooth muscle.

Adenosine Triphosphate↗
PubMed1989

gamma-Glutamyl transpeptidase localization in esophageal exfoliative cytology of a chinese population at risk for carcinoma.

gamma-Glutamyl transpeptidase (gamma-GT) localization in exfoliative esophageal specimens was evaluated in a population of 911 individuals aged 35 or older who lived in an area of China with a high incidence of esophageal squamous carcinoma. Of the total population, 24.4% was positive for gamma-GT. Graded histopathologic cellular classification revealed the following incidences: normal, 10.4% (43 of 413); hyperplasia, 22.0% (44 of 200); Grade I dysplasia, 42.4% (98 of 231); Grade II dysplasia, 46.0% (23 of 50); near-carcinoma, 100% (4 of 4); and squamous carcinoma, 77.0% (10 of 13). In these groups gamma-GT-positive cells were usually from normal esophageal squamous epithelium. A lower incidence of gamma-GT-positive cells was found for dysplastic cells (dysplasia grade I, 6.5% (15 of 231); grade II, 10.0% (5 of 50). The presence of gamma-GT-positive cells in normal esophageal squamous epithelium may prove useful for identification of suspect populations; the presence in dysplastic cells may serve as a diagnostic marker for patients who will soon progress to the carcinoma stage and who should receive early treatment and careful follow-up.

Adult↗
PubMed1989

Characterization and distribution of P2-purinoceptor subtypes in rat pulmonary vessels.

To characterize P2-purinoceptors in pulmonary vessels we have examined the effects of ATP analogs on rat isolated pulmonary artery and vein in vitro. The rank order of potency for causing vasoconstriction was: alpha,beta-methylene-ATP (alpha,beta-meATP) greater than beta,gamma-methylene-ATP (beta,gamma-meATP) greater than 2-methylthio-ATP (2m.S.ATP) greater than ATP for arteries; and alpha,beta-meATP much greater than beta,gamma-meATP = 2m.S.ATP greater than ATP for veins, indicating that a P2x receptor was involved. The contractile response to these analogs was virtually abolished after desensitization of P2x-receptors by alpha,beta-meATP. Removal of the endothelial cells enhanced the contractile responses to all of the ATP analogs in both arteries and veins. The rank order of potency for vasodilatation was 2m.S.ATP much greater than ATP = beta,gamma-meATP much greater than alpha,beta-meATP for arteries and 2m.S.ATP much greater than ATP = beta-gamma-meATP, with alpha,beta-meATP being no effect for veins, indicating a P2y receptor. Pretreatment of the pulmonary arteries with the P2y-antagonist reactive blue 2 caused a rightward shift of the dose-response curves to 2m.S.ATP, ATP and beta,gamma-meATP. Reactive blue 2 was only used with the pulmonary arteries. Removal of the endothelium converted the relaxant responses to all the ATP analogs (except to ATP in pulmonary artery) to further contraction. In the pulmonary artery, the small endothelium-independent relaxation induced by ATP was abolished completely by pretreating the vessels with 100 microM theophylline (a P1-purinoceptor antagonist), suggesting that it was due to conversion of ATP to adenosine.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphate↗
PubMed1989

[Cytomorphological features of fine needle biopsy cytology of mediastinal lesions].

Mediastinal lesions examined by fine needle biopsy cytology in 66 cases are presented. The properties of the lesions were confirmed by cytology in 50 cases. The diagnosis of 40 cases was compared with histopathology. Conformation rate of the diagnosis was 80% (32 out of 40 cases). The diagnosis was correct in 84.2%. Clinical data, such as roentgenologic, physical, hematologic examinations, symptoms and age of the patients may provide important clues for the use of fine needle biopsy cytology in the diagnosis of mediastinal lesions. The cytological characters of thymoma and benign teratoma and differential diagnosis for non-Hodgkin's lymphoma and metastatic small cell carcinoma were discussed. Limitation of fine needle biopsy for the diagnosis of mediastinal lesions wis emphasized.

Biopsy, Needle↗
PubMed1988

Synovial chondromatosis of the temporomandibular joint.

Synovial chondromatosis is a benign, chronic, progressive synovial metaplasia that will not resolve spontaneously. Although it is non-neoplastic, the condition can easily be mistaken histologically as malignant. One Chinese male patient with synovial chondromatosis of the temporomandibular joint is described. Awareness of this rare lesion is important to prevent overdiagnosis and radical treatment. Treatment consists of synovectomy and removal of loose bodies within the joint space.

Chondroma↗
PubMed1988

Detection of styrene oxide-DNA adducts by 32P-postlabeling.

In vitro reaction of DNA with styrene-7,8-oxide (styrene oxide) produced five adducts, as determined by 32P-postlabeling. When styrene oxide was reacted in vitro with deoxyribonucleotides, five adducts were observed from 2'-deoxyguanosine-3'-monophosphate, two from 2'-deoxyadenosine-3'-monophosphate, none from 2'-deoxythymidine-3-monophosphate or 2'-deoxycytidine-3'-monophosphate. Chromatographic comparison of the adducts formed in DNA with those formed with the deoxyribonucleotides suggests that deoxyguanosine is the primary site of DNA modification. Treatment of 9L cells with 1 mM styrene oxide resulted in the formation of several DNA adducts as detected by the postlabeling procedure. Our results indicate that 32P-postlabeling can be used to investigate DNA adducts formed by styrene oxide.

DNA↗
PubMed1988

Detection of styrene oxide-DNA adducts in lymphocytes of a worker exposed to styrene.

The 32P-postlabelling procedure has been used to detect styrene oxide (SO)-DNA adducts. Reactions of SO with DNA and dGMP in vitro produced adducts that were similar, indicating that dGMP was the primary base for modification in DNA. Two SO adducts were also detected in DNA isolated from lymphocytes of a styrene-exposed worker but not in DNA from an unexposed worker. These results indicate that 32P-postlabelling can be used for quantification of DNA adducts in workers exposed to styrene.

DNA↗
PubMed1987

[Gamma-glutamyl transpeptidase-positive cells in esophageal abrasive balloon cytology and their clinical significance].

gamma-glutamyl transpeptidase(gamma-GT) activity of cells from esophageal abrasive balloon cytocollection in 150 outpatients was detected and the characteristics of gamma-GT positive cells were studied in 107/150 cases. The gamma-GT positive cells may have been squamous cancer cells, dysplastic, hyperplastic or normal epithelial cells seen simultaneously or individually on a smear. The normal intermediate and superficial layer cells with positive gamma-GT were very frequently observed on the positive cytological smears. The hyperplastic and dysplastic cells were less frequently observed on the smear as compared with that of the high incidence area. Of 150 specimens, no cancer cells or gamma-GT activity was detected in 35; gamma-GT positive cells were observed in 70 out of 73 positive smears (95.9%); negative cancer cells and gamma-GT positive cells were seen in the rest 42. 25 of these 42 patients were followed and 19 became diagnosed as esophagus cancer by repeated abrasive balloon, biopsy or X-ray examination. It is suggested that the persistent gamma-GT strongly positive cells be a signal of the existence of cancer. In other words, gamma-GT detection on the smears can be used as an adjuvant parameter in cytology to improve cytological diagnosis.

Carcinoma, Squamous Cell↗
PubMed1986

A study of sister-chromatid exchange in peripheral lymphocytes of hepatitis B patients with HBsAg positive and their children.

Previous studies of sister-chromatid exchange (SCE) in patients with hepatitis B have been reported. But as far as we know, no such work has been done in children born to parents with hepatitis B, either one or both of whom are infected. In the present study, frequencies of SCE in the peripheral lymphocytes of 30 hepatitis B parents with hepatitis B surface antigen (HBsAg) positive and 40 of their children were observed. SCE frequencies of 20 normal adults and 3 normal children were analysed for comparison with the patients and their children. The results obtained from all of the samples were as follows: The hepatitis B patients with HBsAg positive had a significantly higher SCE frequency than the normal adults (P less than 0.01); the children born after their parents contracted hepatitis B had a significantly higher SCE frequency than normal children (P less than 0.01); there was no significant difference in SCE (P greater than 0.05) between children born after their parents contracted hepatitis B, children born after their mothers acquired it and children born after their fathers acquired it. The above results indicate that hepatitis B patients with HBsAg positive and their children born after they contracted hepatitis B had significantly higher frequencies of SCE; these data might throw new light on the study of genetic factors acting on the mechanism of hepatitis B.

Child↗
PubMed1986

Hormone changes during the menstrual cycle of Chinese women.

The concentrations of LH, FSH, prolactin, oestradiol and progesterone in serum were measured daily during the menstrual cycle of 100 normal Chinese women. The cyclic changes in LH, FSH, oestradiol and progesterone were typical of ovulatory cycles in women of other ethnic groups as reported in the literature. The geometric mean of the LH midcycle peak value was 51 X 64 i.u./l, the FSH mid-cycle peak value was 11 X 52 i.u./l, the preovulatory oestradiol peak was 1229 X 12 pmol/l, and the progesterone luteal maximum was 53 X 27 nmol/l. The cyclic changes of prolactin concentrations were irregular: the value at mid-cycle was significantly higher than that at the follicular or luteal phases. A correlation between the length of the cycle and mean concentrations of LH and oestradiol at different stages throughout the cycle was shown.

Adult↗