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Biomedical subjects

L Cai

Publications and source records attributed to L Cai.

At least 91 records · Page 5Linked to original sources
PubMed1999

Tumor necrosis factor-alpha mediates lipopolysaccharide-induced macrophage inflammatory protein-2 release from alveolar epithelial cells. Autoregulation in host defense.

Our recent studies have demonstrated that in response to lipopolysaccharide (LPS) challenge, alveolar epithelial cells produced tumor necrosis factor (TNF)-alpha, an early response cytokine in the inflammatory process. To investigate whether LPS-induced TNF-alpha release is related to other inflammatory mediators from the same cell type, we examined effects of LPS stimulation on macrophage inflammatory protein (MIP)-2 production by alveolar epithelial cells, and then examined the relationship between TNF-alpha and MIP-2 production. LPS stimulation induced a dose- and time-dependent release of MIP-2. The steady-state messenger RNA level of MIP-2 was significantly increased, with the MIP-2 protein localized within alveolar epithelial cells, as determined by confocal microscopy. The LPS-induced MIP-2 production is regulated at both the transcriptional and post-transcriptional levels. TNF-alpha also induced MIP-2 production from alveolar epithelial cells. Preincubation with an antisense oligonucleotide against TNF-alpha inhibited LPS-induced TNF-alpha in a dose-dependent and sequence-specific manner. The same antisense also inhibited MIP-2 production. The inhibitory effects were highly correlated. Polyclonal and monoclonal antibodies against TNF-alpha also attenuated LPS-induced MIP-2. These results suggest that LPS-induced MIP-2 release from alveolar epithelial cells may be mediated in part by TNF-alpha from the same cell type. This autoregulatory mechanism may amplify LPS-induced signals involved in host defense as well as in acute inflammatory reactions.

Animals↗
PubMed1999

[Clinical and experimental study on the treatment of endometriosis with dan'e mixture].

OBJECTIVE: To find a medicine to treat endometriosis effectively with less side-effect. METHODS: Dan'e mixture (DEM, consists of Radix Salviae Miltiorrhizae and Rhizoma Zedoariae) was used to treat 189 cases of endometriosis and the change of symptom and sign, the B ultrasonograph, the anti-endometrium antibody and endometriosis quantitative diagnostic index were observed, another 160 cases were treated with Danazol as control, also using animal model to treat with DEM and Danazol. RESULTS: One hundred and eighty-nine cases were treated for 9 months. According to National Standards, 39 cases (20.6%) were cured, 67 cases (35.4%) were markedly effective, 67 cases (35.4%) were effective, and 16 cases (8.4%) were ineffective. Compared with 160 cases treated with Danazol for 9 months, the total effective rates were 95% and 91.5% respectively, the difference between them was insignificant. Animal experiments showed the similar results to the clinical ones. CONCLUSION: SZM is a safe and effective medicine to treat endometriosis, which deserves further study and development. It is particularly helpful for diagnosis, treatment and prevention of endometriosis in the early stage.

Adult↗
PubMed1999

[The effect of blood-pancreatic juice barrier on 5-fluorouracil in post-pancreatoduodenectomy patients].

OBJECTIVE: To observe the distribution and the relationship of 5-Fu in the plasma and the pancreatic juice in post-pancreatoduodenectomy patients after 5-Fu given intravenously. METHODS: After 5-Fu (1.0 g/m(2)) was given intravenously in post-pancreatoduodenectomy patients, blood and pancreatic juice were collected. The 5-Fu concentrations were determined by HPLC and at last the penetration ratio (PR) of 5-Fu was studied with PCNONLIN. RESULTS: 5-Fu in the plasma penetrated the pancreatic tissue and crossed the blood-pancreatic juice barrier (BPJB) in post-pancreatoduodenectomy patients (PR = 1.01 +/- 0.49). The concentration of 5-Fu in pancreatic juice was much higher than that in plasma. CONCLUSIONS: 5-Fu is suitable for adjuvant chemotherapy of pancreatic adenocarcinoma after pancreatoduodenectomy.

Adenocarcinoma↗
PubMed1999

[Effect of preoperative chemotherapy on apoptosis and tissues of pancreatic adenocarcinoma].

OBJECTIVE: To investigate the apoptosis and tissues change of pancreatic adenocarcinoma with or without preoperative chemotherapy and discuss the effect of preoperative regional chemotherapy on pancreatic adenocarcinoma cell. METHODS: Using the method of TUNEL and microscope, we determined the apoptosis of tumor cells and tissues changes in 30 pancreatic adenocarcinoma patients with or without preoperative chemotherapy. RESULTS: The ratio of apoptosis was much higher in the preoperatively treated group than in the untreated group (44.87 +/- 27.78) and (3.6 +/- 3.76)/HP, (P < 0.01). The ratio of apoptosis was related to the tissue type of pancreatic adenocarcinoma. The ratio of apoptosis in the highly differentiated adenocarcinoma group was much higher than that in the middle or low differentiated adenocarcinoma group (P < 0.05, P < 0.01). The inflammatory reaction and the proliferous intima of vessels were more obvious in the preoperatively treated group than in the untreated group (P < 0.05, P < 0.01). CONCLUSIONS: Preoperative regional chemotherapy can effectively inhibit pancreatic adenocarcinoma by inducing the apoptosis of tumor cells.

Adenocarcinoma↗
PubMed1999

[Relationship between glutathione S-transferase M1, T1 genotype and susceptibility to gastric cancer].

OBJECTIVE: The objective of this study was to examine the association between glutathione s-transferase M1, T1 genotype and the risk of gastric cancer. METHODS: A case-control study was carried out and polymerase chain reaction (PCR) technique was used to identify GST M1, GST T1 genotype in 95 cases of primary gastric cancer and 94 controls. RESULTS: The frequency of GST M1 null genotype was 63.16% and 45.74%, respectively in gastric cancer cases and control group, with statistically significant difference (chi(2) = 5.75, P = 0.0165). GST M1 null genotype correlated with the susceptibility to gastric cancer (OR = 2.03, 95% CI of OR = 1.09 - 3.80). The risk for gastric cancer in those with GST M1 null and GST T1 non-null genotype was significantly higher than that in those with GST M1 non-null and GST T1 null genotype, with an OR of 2.91 and 95% CI of ORs 1.09 - 7.89. The risk for gastric cancer in those smoking with GST M1 null genotype increased significantly (OR = 8.06, 95% CI of OR = 2.83 - 23.67). CONCLUSION: GST M1 null genotype was associated with the risk for gastric cancer.

Adult↗
PubMed1999

[Distribution of 5-fluorouracil in plasma and pancreatic tissue of rats during the regional arterial infusion chemotherapy].

OBJECTIVE: Compare the pharmacokinetic parameters of 5-FU in the regional arterial infusion chemotherapy with those in the intravenous chemotherapy. METHODS: Wistar rats were randomly divided into two groups: the intravenous group and the regional arterial infusion group. HPLC was used to measure the concentration of 5-FU in the plasma and the pancreas tissue. Penetration index was calculated. RESULTS: In the intravenous group, maximum concentration (Cmax) of 5-FU in the pancreas was 8.42 micrograms/g and the clearance time of the pancreas was 50 min. In the regional arterial infusion group, Cmax of 5-FU in the pancreas was 20.00 micrograms/g and the clearance time of the pancreas was 90 min. They were both greater than those of the intravenous group. Rd was 2.42. CONCLUSIONS: The regional arterial infusion chemotherapy is a better way for treating pancreatic carcinoma than the intravenous chemotherapy.

Animals↗
PubMed1999

[Apoptosis of human pancreatic carcinoma cell lines induced by combinations of chemotherapeutic drugs].

OBJECTIVE: To investigate the apoptotic in human pancreatic carcinoma cell lines P3, SW1990 and Capan-2 induced by the combined treatment of 5-fluorouracil (5FU), mitomycin C (MMC), carboplatin(CBP) or adriamycine (ADM) or epirubicin (E-ADM). METHODS: The changes of cell morphology were monitored by means of microscopic and fluorescence technique after treated with the combinations of chemotherapeutic drugs. The rate of apoptosis was calculated with flow cytometry and the fragmentation of DNA was measured by agarose gel electrophoresis. RESULTS: The combinations of chemotherapeutic drugs were able to induce the apoptosis of human pancreatic carcinoma cell lines. Compared with the cell necrosis, the dosage of drugs was less and the time was shorter for inducing apoptosis. With the increased dosage and/or the time prolonged for treating the cells, the rate of apoptotic cells was increased. However, the apoptosis reaction of various human pancreatic carcinoma cell lines, which were mentioned above, induced by the same combinations of chemotherapeutic drugs were various different. CONCLUSIONS: The apoptosis process might be a mechanism of an inhibiting cancer cell growth induced by the combinations of chemotherapeutic drugs. The examination of apoptosis reaction for the cells induced by different methods and/or chemotherapeutic drugs could become an important index of testing their ability of inhibiting pancreatic neoplasm.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

The diagnosis and treatment of gastrinoma: report of 17 cases.

OBJECTIVE: To study the experience of diagnosis and treatment of gastrinoma. METHODS: A retrospective study of 17 patients with gastrinoma seen from 1978 through 1998 in PUMC hospital. RESULTS: Three of the 17 cases were associated with multiple endocrine neoplasia type I (MEN-I) syndrome. Tumors dispersed extensively in pancreas (31%), duodenum (25%), lymphnode (19%) and other place (25%). Ultrasonography and computed tomography (CT) were sensitive in localizing tumor in pancreas and liver, but were not so well for small tumor in duodenum and lymph node. The angiography, percutaneous transhepatic portal sampling (PTPS), scintigraphy and endoscopic ultrasonography (EUS) also can be used. Sixteen of 17 patients underwent 38 operations and 56 percent of the 16 cases underwent several operations. Seven patients at last performed total gastrectomy that was still considered as a choice of treatment. Tumor resection was rare because the advancing of tumor in most cases. CONCLUSIONS: Diagnosing gastrinoma in its early stage and striving for the tumor resection and reducing the metastasis of liver were the cruxes for good prognosis.

Adolescent↗
PubMed1998

Intercalated cytosine motif and novel adenine clusters in the crystal structure of the Tetrahymena telomere.

The cytosine-rich strand of the Tetrahymena telomere consists of multiple repeats of sequence d(AACCCC). We have solved the crystal structure of the crystalline repeat sequence at 2.5 A resolution. The adenines form two different and previously unknown clusters (A clusters) in orthogonal directions with their counterparts from other strands, each containing a total of eight adenines. The clusters appear to be stable aggregates held together by base stacking and three different base-pairing modes. Two different types of cytosine tetraplexes are found in the crystal. Each four-stranded complex is composed of two intercalated parallel-stranded duplexes pointing in opposite directions, with hemiprotonated cytosine-cytosine (C.C+) base pairs. The outermost C.C+base pairs are from the 5'-end of each strand in one cytosine tetraplex and from the 3'-end of each strand in the other. The A clusters and the cytosine tetraplexes form two alternating stacking patterns, creating continuous base stacking in two perpendicular directions along the x - and z -axes. The adenine clusters could be organizational motifs for macromolecular RNA.

Adenine↗
PubMed1998

[Expression of human SRY gene and the DNA-binding property of its product].

OBJECTIVE: To investigate the role which human SRY gene plays in the regulation of the downstream gene. METHODS: The fragment of SRY (sex determinating region on the Y chromosome) HMG domain was cloned into the expressing vector pET-15b. The hSRY gene recombinant plasmid-pETSY was transformed and expressed in E.coliBL21. The target protein was purified by pET His. Tag system. The DNA-binding retardation test and its competitive reaction were conducted between SRY protein and the fragment of Mullerian inhibiting substance (MIS) promoter. RESULTS: The molecular weight of the expressed hSRY protein was shown to be approximately 21kD. The specific DNA binding property of SRY protein to the fragment of MIS was confirmed in the retardation test and its competitive reaction. CONCLUSION: The results suggest that the product of SRY gene can bind the MIS promoter region and may initiate the transcription of MIS.

DNA-Binding Proteins↗
PubMed1998

Protective role of zinc-metallothionein on DNA damage in vitro by ferric nitrilotriacetate (Fe-NTA) and ferric salts.

Oxidative DNA damage can be caused by radicals generated by transitional metals like iron in Fenton reaction. Metallothionein (MT) may play an important role in preventing oxidative DNA damage. Therefore, after comparing the effects of ferric salts (Fe), and complexes of ferric salts with nitrilotriacetic acid (Fe-NTA) on DNA damage, the protective effects of zinc-MT (Zn-MT) on DNA damage of Fe salts or Fe-NTA were investigated in vitro. DNA damage was measured by loss of fluorescence of DNA binding to ethidium bromide, and also by increased DNA mobility in agarose gel electrophoresis. Both Fe salts and Fe-NTA could induce calf thymus DNA damage in presence of hydrogen peroxide and ascorbate. However, the degree of DNA damage was lower with Fe salts than that with Fe-NTA complex. Addition of 50 microM Zn-MT could only protect DNA from Fe-NTA, but not from Fe salt induced damage. The protective effect of MT was about five times better than that of glutathione (GSH). These results suggest a potential role for MT in protection from Fe-NTA-induced DNA damage.

Animals↗
PubMed1998

Protective effects of extracted human-liver RNA, a known interferon inducer, against radiation-induced cytogenetic damage in male mice.

Cells in vitro or in vivo pre-exposed to low-dose radiation (LDR) or low concentrations of chemical mutagens became more resistant to large-dose radiation-induced DNA or chromosome damage. This was known as radio-adaptive response, for which the exact mechanism was unclear. However, multiple cellular and molecular responses to LDR have been documented, for instance, the induction of some cytokines such as interferon (IFN). Administration of exogenous IFN to cultured cells or mice showed marked radio-protection. In the present study, we investigated the in vivo radio-protective effects of extracted human liver RNA (HL-RNA), a known IFN inducer, indirectly to determine the radio-protective action of endogenous IFN. First, mice were administered with 6.25 mg/kg HL-RNA at different times before exposure to radiation and the 24 h pretreatment offered the optimal protective action for HL-RNA on cytogenetic effects in bone marrow cells. When the mice were treated with different concentrations of HL-RNA for 24 h, a wide dose-range (25-100 mg/kg) of HL-RNA resulted in a marked protection from X-ray-induced chromosome aberrations in both bone marrow cells and germ cells. In subsequent experiments, a protective effect of pretreatment with 25 mg/kg HL-RNA for 24 h was also found for radiation-induced micronuclei in polychromatic erythrocytes (PCE), and inhibition of DNA repair ability (unscheduled DNA synthesis, UDS). These results demonstrated that HL-RNA, an IFN inducer, is able to offer significant cytogenetic protection from radiation, implying indirectly that the induction of IFN by LDR may also play a protective role as one of the mechanisms in the induction of the cytogenetic adaptive response.

Animals↗