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S Z Liu

Publications and source records attributed to S Z Liu.

At least 37 records · Page 2Linked to original sources
PubMed1994

Experimental radiotherapy and metastasis of human lung cancer xenografts in nude mice.

Using a cell line derived from human lung cancer (AOI), we successfully established human xenografts in KSN nude mice, which showed high incidence of multiple spontaneous metastases. The highest incidence of metastasis in untreated hosts was observed in the spleen followed by the lungs and lymph nodes. The rate of metastasis reached 100% in the mice bearing large sized tumors, when metastasis to any organ or tissue was counted. Experimental radiotherapy caused remarkable redistribution of metastatic foci among different organs. Lung metastasis tended to decrease, while metastasis to the liver and the kidney was increased after radiotherapy. Radiation-induced production of cytokines was speculated to be responsible for such an alteration of metastasis pattern.

Animals↗
PubMed1993

[Protective effect of panaxatriols on function of reproductive endocrine axis in radiation-injured rats].

After whole body irradiation with X-ray 5 Gy (radiation condition: 0.31 Gy.min-1, 200 kV, 10 mA, 0.5 mm Cu and 1.0 mm Al), the male rats were given ip panaxatriols 5 mg.d-1 24 h before and after irradiation for 14 d. The results showed that hypothalamic leu-enkephalin (165 +/- 12 vs 131 +/- 14 pg.mg-1), pituitary beta-endorphin (2.3 +/- 0.5 vs 1.6 +/- 0.3 ng.mg-1) contents, and serum testosterone (1.66 +/- 0.15 vs 0.82 +/- 0.23 ng.ml-1) level were decreased, while serum FSH (1.34 +/- 0.10 vs 1.99 +/- 0.10 ng.ml-1) level increased in irradiation group vs normal control. These indices approached to control levels in irradiation + panaxatriols group. These suggest that panaxatriols have protective effects on reproductive endocrine axis and promote their recovering course from the radiation injuries.

Animals↗
PubMed1992

Protein profiles of perilymph and endolymph of the guinea pig.

Results of protein separation of guinea pig plasma, perilymph, and endolymph by means of high-resolution two-dimensional sodium dodecyl sulfate polyacrylamide gel electrophoresis are presented. Several proteins are present in perilymph at levels in basic accord with the total protein gradient with respect to plasma; however, others are present in perilymph at levels comparable to plasma levels, and one protein low molecular weight protein, PLS:33, is eight times higher. In addition, a high molecular weight protein is shown to be present at similar levels in the two compartments. These findings indicate that ultrafiltration cannot be the sole mechanism of perilymph production. Endolymph proteins are uniformly five to eight times lower than perilymph levels, essentially following the total protein concentration gradient between the two compartments. This supports the view that endolymph is derived from perilymph rather than directly from blood.

Animals↗
PubMed1992

EPR study of mouse tissues in search for adaptive responses to low level whole-body X-irradiation.

Effect of a low dose of whole-body X-irradiation (D1 = 0.075 Gy) of mice on some biochemical changes induced in the spleen and thymus by a subsequent challenge dose (D2 = 1.5 Gy) was studied by electron paramagnetic resonance (EPR). Kunming and SHK mice were used. Concentration of ribonucleotide reductase (RR) in the spleen and thymus of unirradiated Kunming mice was 0.70 and 0.46 microM respectively, and of unirradiated SKH mice--0.37 and 0.21 microM respectively (systematic error 45%). For mice exposed only to the low dose (D1 group), a stimulating effect on RR activity in spleen and thymus was found, while in mice subjected only to the D2 dose (D2 group) activity of the enzyme in the organs decreased considerably 18 h after irradiation. The group of mice irradiated with D1 and D2 doses, given at a 6-h interval (D1 plus D2 group), showed a RR activity in the organs lower than D1 and higher than D2 groups. This finding indicates that there exists an adaptation-like response to a low-dose whole-body irradiation in murine spleen and thymus. This low 'inductive' dose makes the organs' RR less susceptible to inhibition induced by a subsequent challenge dose. Preliminary results showed that the same kind of response is probably a characteristic of the RR content of splenocytes as well as of the rate of thymidine incorporation into splenocytes. 5-Thyml radicals of DNA (TH radicals) induced in whole tissues by gamma-irradiation in vitro at 77 K were also studied. Radiochemical yield of these radicals (4.0 and 5.3 nmol j-1), for spleen and thymus respectively of unirradiated Kunming mice, and 2.3 and 2.6 nmol J-1, for spleen and thymus respectively of unirradiated SHK mice (systematic error 30%), decreased significantly in both organs upon D2 irradiation. This decrease, however, was the consequence of DNA content diminishing upon D2 irradiation rather than change of DNA radiosensitivity: the beta value of TH radicals, i.e. yield of radicals per unit mass of DNA in each organ was equal for the mice from all D1, D1 plus D2, D2 and control groups. The beta values of TH radicals in mouse spleen and thymus were of the same order of magnitude compared with the yield of the single-strand breaks of DNA measured previously in rat organs just after whole-body irradiation, i.e. about 1 x 10(2) (Gy x 10(12) Da)-1.

Adaptation, Physiological↗
PubMed1992

Study on the mechanism of cytogenetic adaptive response induced by low dose radiation.

Pre-exposure of human lymphocytes to low dose radiation (D1) could induce a cytogenetic adaptive response expressed as a decrease of chromatid aberrations caused by subsequent large dose radiation (D2). There are two possible explanations for its mechanism, i.e., activation of enzymatic processes by D1 facilitating repair of chromosomal damage and induction of protective proteins by D1 reducing the number of chromosomal aberrations. The results here showed: (1) the cytogenetic adaptive response could be enhanced by hyperthermia (41 degrees C and 43 degrees C) and suppressed by hypothermia (4 degrees C); (2) hyperthermia (41 degrees C) alone could also induce the cytogenetic adaptive response; (3) the cytogenetic adaptive response could be inhibited by cycloheximide--an inhibitor of protein synthesis; (4) supernatant from cultured lymphocytes treated with D1 failed to show the protective effect. The results imply that the cytogenetic adaptive response is not only related to the activation of repair enzymes, but also to the induction of protective proteins.

Cells, Cultured↗
PubMed1991

[Cytogenetic adaptive response induced by low dose radiation].

Human and rabbit peripheral blood lymphocytes were irradiated in vitro with 1.5 Gy x-rays after exposure to 0.01 Gy of x-rays (dose rate: 0.01 Gy/min). The frequency of chromosome aberration in the cells pre-exposed to 0.01 Gy of x-rays at Go, G1, S and G2 phases of cell cycle respectively was markedly lower than that in the cells irradiated with 1.5 Gy alone (P less than 0.01). This adaptive response would last for 3 cell-cycles, beyond which the damage of the chromosome following the second large dose occurred with the same magnitude as that without a previous conditioning exposure. However, when the low dose was repeated after the third cell cycle the adaptive response could be revived. Meanwhile, it was found that the adaptive response could be also induced in vivo in the bone marrow cells and germ cells of mice by low dose irradiation. In addition, the effect of dose rate of the first irradiation on the induced adaptive response was also studied.

Adaptation, Physiological↗
PubMed1990

Induction of cytogenetic adaptive response of somatic and germ cells in vivo and in vitro by low-dose X-irradiation.

The cytogenetic adaptive response induced by low-level radiation was studied using human and rabbit lymphocytes in vitro and bone marrow cells and germ cells in vivo. The inductive dose of X-rays was 10 mGy for the in vitro studies at a dose rate of 10 mGy/min, and 2, 10, 50, 75 and 100 mGy for the in vivo studies at a dose rate of 50 mGy/min. The challenging dose was 1.5 Gy X-rays for the in vitro experiments and 0.65 or 0.75 Gy for the in vivo experiments at a dose rate of 0.44 Gy/min. The results reported here, in addition to those that have appeared in the literature, show the following characteristics documented for the first time: (1) 10 mGy could induce the adaptive response in human as well as rabbit lymphocytes irradiated not only in G1, S and G2 phases, but also in the Go state; (2) although the induced adaptive response could only last three cell cycles, it could be revived when the inductive dose was repeated after the third cell cycle; (3) the adaptive response could be induced by low-dose X-rays in somatic cells, both in vitro (lymphocytes) and in vivo (bone marrow cells), and also in germ cells (spermatocytes); (4) the magnitude of the adaptive response induced by whole-body irradiation was found to be dose-dependent--the lower the inductive dose the more the reduction of the frequency of chromatid aberrations following the challenging dose.

Adaptation, Biological↗
PubMed1990

Effect of low-dose radiation on repair of DNA and chromosome damage.

In this report results of studies on the effect of different doses of low LET (linear energy transfer) radiations on the unscheduled DNA synthesis (UDS) and DNA polymerase activity as well as the induction of adaptive response in bone marrow cells (BMC) by low dose radiation were presented. It was found that whole-body irradiation (WBI) with X-ray doses above 0.5 Gy caused a dose-dependent depression of both UD5 and DNA polymerase activity, while low dose radiation below 250 mGy could stimulate the DNA repair synthesis and the enzyme activity. WBI of mice with low doses of X-rays in the range of 2-100 mGy at a dose rate of 57.3 mGy per minute induced an adaptive response in the BMC expressed as a reduction of chromosome aberrations following a second exposure to a larger dose (0.65 mGy). It was demonstrated that the magnitude of the adaptive response seemed to be inversely related to the induction dose. The possibility of induction of adaptive response in GO phase of the cell cycle and the possibility of a second induction of the adaptive response were discussed.

Adaptation, Physiological↗
PubMed1990

A case of heterotopic transplantation after bilateral traumatic above-knee amputations.

This paper describes a case in which a young woman's two lower limbs were crushed and amputated from the upper part of the thighs by a train. She was in serious hypovolemic shock at the time. With rapid infusion of intravenous fluids, she recovered from shock quickly, avoiding acute renal failure and ARDS. Heterotopic transplantation was performed. Two years later, the limb which had undergone heterotopic transplantation had partly restored function.

Adult↗
PubMed1990

[Pharmacokinetics of albendazole and its metabolites in human body].

High-performance liquid chromatography method was used to determine blood sulfoxide and sulfone, two metabolites of albendazole. Methanol containing 0.4% acetic acid was employed as mobile phase. Wavelength of 290 nm was chosen for uv-detector and mebendazole was used as internal standard. After a single dosage of albendazole 25 mg/kg was taken orally by healthy volunteers and neurocysticercosis patients, sulfoxide and sulfone were found in blood at 20 and 40 min respectively. The blood peak level appeared at 6 h on an average. The metabolites remained as long as 58-72 h in human blood.

Adult↗
PubMed1989

[An experiment on technology for flow granulating of traditional Chinese medicine].

The influence for flow granulating of traditional Chinese medicine to be taken after being mixed with boiling water: spray air pressure greater than powder granularity greater than inlet, exit temperature greater than wind speed. Optimum condition: inlet temperature 110 degrees C, exit temperature 50 degrees C; spray air pressure 1.0 kgf/cm2; sugar powder granularity: 40-60 eye; wind speed: 1.5 gear. It is necessary to provide reference basis for production by pilot test.

Air Pressure↗
PubMed1989

Radiation hormesis. A new concept in radiological science.

Low-dose ionizing radiation caused definite stimulation of immune reactions both in humans and mice. The PFC reaction in response to SRBC immunization and the NK activity of the splenocytes were significantly enhanced after low-dose whole body irradiation. Activation of the T lymphocytes, especially the TH, with increased production of IL-2, might be a critical step in the whole process of immunoenhancement. A single dose of 75 mGy X-rays caused significant lowering of hypothalamic M-Enk content as well as serum corticosterone level. The increased serum testosterone level would exert an inhibitory influence on the CRF-ACTH-CS system to keep the blood corticosterone at a lower than normal level which might facilitate the immune reactions in the SRBC-immunized animals. The increased catecholamines in the spleen would probably reinforce this effect resulting in immunoenhancement. Low-dose ionizing radiation caused increased repair of the genetic material at both the molecular and subcellular levels. The UDS of human and murine lymphocytes was augmented by single or continuous low-dose irradiation. The stimulation of DNA polymerase activity might be responsible for such effects. Exposure to very small doses of low LET radiation could induce in different tissues an adaptive response which alleviated chromosome damage caused by subsequent larger dose radiation. Such an adaptive response could be induced both in vivo and in vitro in different animal species. The induced adaptive response faded away after 3 cell cycles could be re-induced by a second exposure to low-dose radiation. The mechanism of the inductive process needs further study.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Radiation hormesis: its expression in the immune system.

The effects of low-dose single and continuous whole-body irradiation on immune functions were studied in C57BL/6 mice. Plaque-forming cell reaction of the spleen was found to be stimulated by single doses of x rays in the range of 0.025 to 0.075 Gy and by continuous exposure to gamma rays with a cumulative dose of 0.065 Gy. The reactivity of thymocytes to interleukin 1 showed a dose-dependent depression in the dose range of 0.025 to 0.25 Gy, but there was an increase in cell number in the thymus between doses of 0.025 and 0.10 Gy, resulting in enhancement of reaction of the whole organ. Unscheduled DNA synthesis of spleen cells was stimulated by single irradiation with 0.05 Gy and continuous irradiation with a cumulative dose of 0.13 Gy. The implications of these immunologic changes under low-dose radiation are discussed.

Animals↗
PubMed1986

Biochemical markers of tumor diathesis and early cancer.

Many biochemical parameters have been used as tumor markers but few are satisfactory to reflect tumor diathesis and/or for early detection. Studies in the Cancer Institute, Chinese Academy of Medical Sciences, have indicated that serum alpha 1-acid glycoprotein and sialic acid were increased in lung cancers, but 20% of pulmonary tuberculosis patients were also positive. Serum polyamines determined by RIA were increased in cancer patients. The positive rates for cancer of lung and esophagus were 84% and 100%, respectively. Polyamine contents considerably increased in esophagus tissue of rats treated with methylbenzylnitrosamine, and this occurred far earlier than the tumor appeared. However, whether serum polyamine can be used for early detection of esophageal cancer awaits further studies. An unknown fluorescent compound in urine was found in normal people but was very much decreased in cancer patients. This compound showed cytostatic effect on tumor cells in vitro. Serum antibodies against EBV-associated DNase could be used as a marker for NPC.

Animals↗