Biomedical subjects

L Bai

Publications and source records attributed to L Bai.

82 records · Page 5Linked to original sources

PubMed1991

Effects of antioxidants on survival of adult rat hepatocytes under various oxygen tensions in serum-free primary culture.

Effects of antioxidants, such as superoxide dismutase, vitamin C, vitamin E, 4-(0-benzylphenoxy)-N-methylbutylamine hydrochloride (bifemelane), and selenite on survival of adult rat hepatocytes were examined under normoxic and hyperoxic conditions in serum-free primary culture. The tested antioxidants, except for vitamin C, significantly increased the survival rate of hepatocytes under the normoxic condition (under air). Thus, even the normoxic culture condition is hyperoxic for hepatocytes. Elevation of oxygen tension (40% O2) caused severe morphologic degeneration of hepatocytes and remarkable decrease in the survival rate of the cells. Addition of the antioxidants effectively protected hepatocytes from the morphologic degeneration, and significantly improved the survival of the cells under the hyperoxic condition. These findings indicate that the antioxidants can maintain the long-term survival of hepatocytes in serum-free primary culture.

Animals↗

PubMed1991

[Effect of electroacupuncture on the contents of substance P in the nucleus of the solitary tract in rats].

Six pairs of rats were used in the experiment. The sciatic nerve was stimulated in one of every pair with the electric needle. Then the substance P (SP-like immunoreactive nerve fibers in the nucleus of the solitary tract (NST) were showed with immunohistochemical technique (ABC METHOD). The other of every pair was as the control. All experimental procedures were the same as the electroacupuncture group except that the sciatic nerve wasn't stimulated. The contents of SP of NST (at the area postrema segment) of both the electroacupuncture and the control were measured with the micro-spectroscopic image analyser. The results obtained were as follows: 1. The distribution positions of SP-like immunoreactive nerve fibers in the electroacupuncture group were the same as in the control group. That is, SP-like immunoreactive nerve fibers distributed from the caudal part to the rostral part in NST. 2. The contents and the area of SP-like immunoreactive nerve fibers of the electroacupuncture were more than the control. There was a significant difference between the two groups. The results mentioned above suggested that the role of NST is involved in the acupuncture analgesia.

Acupuncture Analgesia↗

PubMed1990

Enhancing effect of S-(1,2-dicarboxyethyl)glutathione on epidermal growth factor-stimulated DNA synthesis in primary cultures of adult rat hepatocytes.

A tripeptide S-(1,2-dicarboxyethyl)glutathione (DCE-GS) has been reported to be present in the lens, liver, and heart. Effects of DCE-GS and its derivatives and analogues on hepatocyte deoxyribonucleic acid (DNA) synthesis were examined using primary cultures of adult-rat hepatocytes. DCE-GS alone had no effect on DNA synthesis of hepatocytes. However, when DCE-GS was added with epidermal growth factor (EGF), the tripeptide effectively enhanced EGF-stimulated DNA synthesis of hepatocytes under the culture conditions of low cell density, but not high cell density. On the other hand, some esters and amides of DCE-GS and DCE-GS analogues showed a suppressive effect on DNA synthesis of hepatocytes in the absence of EGF. The derivatives and analogues together with EGF had no effect or rather a suppressive effect on stimulation of hepatocyte DNA synthesis by EGF. Therefore, the two carboxy groups in the substituent probably play an important role in the stimulative activity of DCE-GS. In addition, it seems likely that one of in vivo physiological roles of DCE-GS is related to liver regeneration.

Animals↗

PubMed1990

Influence of liver tumor promoters and structurally related chemicals on survival of normal adult rat hepatocytes in primary culture.

The influence of four liver tumor promoters and two structurally related chemicals (non-promoters) on survival of normal adult rat hepatocytes was examined in primary culture. Of the four promoters, butylated hydroxytoluene (BHT), dichlorodiphenyltrichloroethane (DDT), barbital sodium and phenobarbital sodium, only phenobarbital efficiently prolonged the hepatocyte survival and maintained the morphological features of the cells. Both BHT and DDT were toxic to hepatocytes within the dose ranges tested. Barbital was also ineffective for maintenance of primary cultured hepatocytes but not toxic to the cells. Of the two non-promoters, barbituric acid and amobarbital, barbituric acid also showed no maintenance effect on hepatocytes. However, amobarbital resembled phenobarbital in its effect on the maintenance of hepatocytes in primary culture. DNA synthesis of primary cultured hepatocytes was severely suppressed by phenobarbital in a dose-dependent manner. The results clearly show that the ability to support long-term survival of primary cultured hepatocytes is a common property of some barbiturates but not of liver tumor promoters, and that the maintenance of hepatocytes by phenobarbital is not due to a counterbalance of stimulated proliferation and death of the cells.

Animals↗

PubMed1990

[Diagnosis of pancreatic cancer with simultaneous detection of a pancreatic-cancer-associated antigen and pancreas-specific antigen].

We reported the purification and characterization of a pancreatic cancer-associated antigen from normal colonic mucosa (PCAAc) and pancreas-specific antigen (PaA) according to Kitada's and Loor's methods as well as the established method of double antibody enzyme-linked immunoassay for the detection of serum PaA and PCAAc; respectively. In our study, 155 serum samples were detected (including normal controls 40; pancreatic cancer 31; other malignant disease 56 and benign diseases 28). The results indicated that the overall sensitivity and specificity of a single PCAAc test for pancreatic cancer were calculated to be 70.98% and 96.43%; a single PaA to be 80.65% and 95.23%, respectively. Furthermore, the sensitivity and specificity of combined tests (PCAAc and/or PaA) for pancreatic cancer were calculated to be 96.77% and 90.91%. The diagnostic efficiency was 90.91%. None of 84 cases of nonpancreatic cancer and benign diseases has been found elevated PCAAc and PaA simultaneously. The results suggest that simultaneous detection of PCAAc and PaA would have increased the sensitivity of diagnosis for pancreatic cancer.

Antigens, Neoplasm↗

PubMed1989

[Effects of 2[p-(dimethylamino)styryl] pyridine methiodide on mouse and rabbit].

The effects of 2[p-(dimethylamino)styryl] pyridine methiodide on mouse and rabbit ECG and on the contraction of isolated rabbit atrial muscles were studied. DSPM produced long-lasting bradycardia and A-V block in a dose-dependent manner, but did not effect intraventricular conduction. DSPM antagonized the positive chronotropic and dromotropic effects of isoprenaline (Iso) in vivo, and antagonized the inotropic effects of Iso and CaCl2 non-competitively in vitro. The pD'2 were 4.49 and 4.52, respectively. It is suggested that DSPM may be a Ca2+ antagonist.

Animals↗

PubMed1989

[Surface accuracy of hydrophilic impressions. 1].

The purpose of this study was to examine detail reproducibility and surface roughness of stone models made from silicone, polysulfied rubber, alginate and agar impression materials using stainless steel test block (ISO). In addition, the influence of artificial saliva was studied. The following results were obtained: 1. Silicone impression materials showed the best detail reproducibility of all materials. 2. When artificial saliva was dropped on the stainless steel test block, hydrophilic silicone impression material showed the best detail reproducibility. 3. In the test using artificial saliva, alginate and agar impression materials showed better surface roughness, but poorer detail reproducibility than silicone impression ones. 4. Hydrophilic silicone material indicated the highest detail reproducibility, and the lowest surface roughness in the test using artificial saliva.

Dental Impression Materials↗

PubMed1987

[COMVp regimen in the treatment of small cell lung cancer--report of 106 patients].

One hundred and six consecutive small cell lung cancer patients were treated by a combination regimen COMVp (CTX 1,000-1,400 mg IV D 1,8; VCR 1-2 mg IV D 1,8; MTX 20-40 mg IV or IM D 3,5,10,12; VP-16 100 mg IV drip D 3-7; three weeks as a cycle and 2-3 cycles as a course) in our hospital during 1983 to 1984. Among the 95 patients who were evaluated, 10 (10.5%) gave CR, 57 (60%) PR, 19 (20%) no change and 9 (9.5%) progression. The overall response rate was 70.5%. In this paper, factors influencing the response and side effects are also analysed. The data show that COMVp regimen is one of the good front line combination chemotherapy regimens currently available in the management of small cell lung cancer.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

Extended effects of human papillomavirus 16 E6-specific short hairpin RNA on cervical carcinoma cells.

Most cervical carcinomas express high-risk human papillomavirus (HPV) E6 and E7 oncogenes. Small interfering RNA can mediate sequence-specific inhibition of gene expression in mammalian cells. To find a most effective short hairpin RNA (shRNA) for HPV16 E6 messenger RNA (mRNA) and investigate the extended effects of the HPV16 E6 shRNA on cervical carcinoma cells, we stably transfected SiHa cells with four shRNA expression vectors (E6A-D). HPV16 E6A shRNA was found to be the most efficient in our study, which caused the reduction of HPV16 E6 mRNA to 10% in SiHa cells but did not reduce HPV18 E6 mRNA expression in HeLa cells. We subsequently demonstrated that E6A could stably express shRNA and effectively reduce HPV16 E6 and E7 viral genes expression in SiHa cells for more than 4 months. After E6 and E7 repression, there was a dramatic accumulation of p53, p21, and hypophosphorylated pRb proteins in cells. Furthermore, cell proliferation, colony formation ability, tumorigenicity, and in vitro cell invasive capability were suppressed substantially in E6A-transfected cells. These results suggest that the use of shRNA expression vector may be a potential approach for the treatment of persistent HPV infection and HPV-positive cervical carcinoma.

Animals↗

PubMedDate not supplied

A human B-cell CLL model established by transplantation of JOK-1 cells into SCID mice and an anti-leukemia efficacy of fludarabine phosphate.

The present study was carried out to establish a human chronic lymphocytic leukemia (CLL) mouse model by transplantation of a JOK-1 human CLL cell line into SCID (severe combined immunodeficient) mice and to examine anti-leukemic effects of fludarabine phosphate, a prodrug of 9-beta-D-arabinofuranosyl-2-fluoroadenine (2F-ara-A). In vitro cytotoxic screening pattern of 2F-ara-A differed from those of other anticancer agents. Intraperitoneal inoculation with JOK-1 cells in SCID mice allowed the cells to infiltrate into a variety of organs including the liver and thymus, and resulted in the death of the mice with a median survival time of 29.5 days, associated with hepatomegaly, splenomegaly and enlarged lymph nodes. The ascitic cells expressing the human B-lymphocytic cell surface antigen CD19 actually grew after a latent period of 15 days. In this model, twice daily administration of fludarabine phosphate at a dose of 135 mg/kg for 5 days prolonged the survival time of the mice for considerably longer period than once-a-day treatment. Fludarabine phosphate in the doubled course of twice daily increased life span of 32.9%, which was in a similar range to that of doxorubicin. Thus, intraperitoneal inoculation of the human JOK-1 CLL cells into SCID mice seems to serve as an animal model potentially for human leukemia, suggesting that transplantation and subsequent infiltration processes of human CLL cells is useful measures to explore mechanistic aspects for drug-induced modulation of the tumor progression.

Animals↗