Biomedical subjects

R Han

Publications and source records attributed to R Han.

At least 109 records · Page 6Linked to original sources

PubMed1993

Fetal lung epithelial cells express receptors for platelet-derived growth factor.

There is increasing evidence to suggest that platelet-derived growth factor (PDGF) or PDGF-like molecules play a role in fetal lung morphogenesis. Our previous studies demonstrated that fetal lung epithelial cells respond mitogenically to exogenous PDGF, while fetal lung fibroblasts respond with increased glycosaminoglycan synthesis. To further study the target cells of PDGF in fetal rat lung, we investigated the presence and nature of PDGF receptors in fetal lung cells. Functional PDGF receptors were expressed on normal epithelial cells of fetal rat lung. All three isoforms of PDGF (AA, AB, and BB) were mitogenic for quiescent epithelial cells. Northern blot and protein analysis demonstrated the presence of PDGF alpha-receptor and PDGF beta-receptor. All isoforms of PDGF enhanced tyrosine kinase activity and stimulated receptor autophosphorylation. In contrast, fetal lung fibroblasts expressed only the PDGF beta-receptor. PDGF-AB and PDGF-BB, but not PDGF-AA, stimulated tyrosine kinase activity. No PDGF isoform was mitogenic for quiescent fibroblasts. However, PDGF-BB stimulated fibroblast proliferation on a collagen type I substratum in the presence of transferrin. Binding experiments with [125I]PDGF-AA and [125I]-PDGF-BB to epithelial cells and fibroblasts confirmed these observations.

Animals↗

PubMed1993

[Anti-oxidative effects of R8605, a third-generation retinoid].

The anti-oxidative effects of R8605, a compound of the third generation retinoids, have been studied. R8605 exhibited pronounced inhibitory effects on FeSO4/cysteine and NADPH/vitamin C-induced lipid peroxidation of rat liver microsome as well as on H2O2-induced lipid peroxidation of erythrocytes: Their IC50's were 9.8, 17.6 and 20.3 mumol/L, respectively. R8605 decreased the generation of superoxide anion (O2-.) in a xanthine/xanthine oxidase system and also elevated hepatic superoxide dismutase (SOD) activity in mice. Therefore R8605 shows potent antioxidative effects and this is likely of importance in its chemopreventive actions.

Animals↗

PubMed1993

[Combination induction of cell differentiation of HL-60 cells by daidzein (S86019) and BC-4 or Ara-C].

Experiments demonstrated that the cell differentiation of HL-60 cells induced by low concentrations of daidzein (S86019), BC-4 (active principle of Boswellia carterii Birdw) and Ara-C was not impressive. However, when they were used in combination 80% of HL-60 cells exhibited NBT reduction and 82% of the cells showed phagocytosis after four days exposure to daidzein and BC-4. When HL-60 cells were exposed to daidzein and Ara-c, 70% of the cells exhibited NBT reduction and phagocytosis. Flow cytometry indicated that the majority of the cells were blocked at G1 phase under the induction of combination of daidzein with BC-4 or Ara-C.

Cell Cycle↗

PubMed1993

Salivary excretory index--quantification of the ascorbic acid response in dynamic radionuclide sialography.

Dynamic radionuclide sialography (DRS) provides data about the aptitude of salivary glands to accumulate the tracer and to secrete the saliva. Visual interpretation of the t/a curves may be onerous when salivary glands uptake function is impaired. The purpose of the study has been to quantify the ascorbic acid (AA) response by means of salivary excretion index (SEI). DRS was performed in 10 healthy subjects and in 118 patients with various diseases of the parotid glands. Data acquisition (80 frames/15 s) started simultaneously with i.v. administration of 99mTcO4. Fifteen minutes later AA was given per os. Regions of interest were set over parotid glands. SEI was derived using the formula: SEI = (2b-a-c)/b, where a, b and c were cpm 3 minutes prior, in the moment when, and 3 minutes after AA was given. In 9 of 10 controls SEI was greater than 55 (mean = 63.2). Results in patients with Sjögren's and Mikulicz's syndrome and sialoadenitis, were significantly lower than in healthy subjects. Lowest results were found in patients with sialolithiasis. It may be concluded that SEI improves objective assessment of the AA response particularly in patients with minute or asymmetric disorders of salivary glands function.

Ascorbic Acid↗

PubMed1993

The clinical use of 131I-meta-iodo-benzylguanidine (MIBG) for the diagnosis of neuroblastoma.

Whole-body scintigraphy with 131I-meta-iodo-benzylguanidine 131I-MIBG) was performed in 41 patients with neuroblastoma. In patients with clinical remission no pathological concentration of 131I-MIBG was found. In 30 patients with residual, recurrent or metastatic disease neuroblastoma was correctly localized by 131I-MIBG scintigraphy. It is concluded that 131I-MIBG whole-body scintigraphy is useful in the diagnosis and follow-up of neuroblastoma.

3-Iodobenzylguanidine↗

PubMed1992

Linkage of regression and malignant conversion of rabbit viral papillomas to MHC class II genes.

Human papillomaviruses associated with cutaneous and anogenital cancers induce intraepithelial precursor lesions which may regress spontaneously or progress into invasive carcinomas. Cell-mediated immune responses are probably involved in regression of precancerous lesions and the polymorphism of the genes responsible may thus have a key role in the variability of the host response. Skin warts and cancers induced in rabbits by Shope papillomavirus provide a model to test this hypothesis. We analysed a restriction-fragment-length polymorphism of major histocompatibility complex class I and class II genes and T-cell receptor beta-chain genes in infected domestic rabbits. We found a strong linkage between wart regression and a DR alpha EcoRI fragment, and an increased relative risk of malignant transformation associated with a DQ alpha PvuII fragment. This indicates a genetic control of wart evolution, involving genes in the class II region of the major histocompatibility complex.

Animals↗

PubMed1992

Androgen-producing bilateral large cortical adrenal adenomas associated with polycystic ovaries in a young female.

An association of bilateral large adrenocortical androgen-producing adenomas with polycystic ovaries in a young female is presented. She developed mild hirsutism and secondary amenorrhoea at the age of 17, and was treated for 3 years with an anti-androgen (cyproterone acetate) and ethinyloestradiol. Routine follow-up at the age of 21 showed bilateral large adrenal tumours and polycystic ovaries, together with high serum testosterone and dehydroepiandrosterone sulphate values. Bilateral adrenalectomy was performed, which resulted in lowering of the elevated androgens, and large bilateral adrenocortical adenomas were confirmed histologically. Contrary to expectations, the polycystic appearance of the ovaries persisted after adrenalectomy. This case supports the possible role of adrenal androgens in the pathogenesis of polycystic ovaries as well as the possibility of the persistence of polycystic ovaries without adrenal androgens once they have developed.

Adenoma↗

PubMed1992

[Inhibitory effects of several antitumor drugs on the growth of HL-60 cells in SRC of mice].

Human promyelocytic leukemia HL-60 cells provide a useful model system for the study of cell differentiation in vitro. Here the growth of HL-60 cells as a solid clot with fibrin in subrenal capsules (SRC) of mice was studied. The cell volume of HL-60 cells increased 5 and 15-fold between 6-9 days after transplantation into normal and CYT immunosuppressed mice, respectively. Histological study revealed typical proliferation and invasion characteristics of HL-60 cells and higher tumor cell density. RA, RII, Ara-C, Harringtonine and HMBA significantly inhibited the growth of HL-60 cells in SRC of mice. This model provides a useful system for the study of the effect of drugs on cultured tumor cells or leukemia cell lines in vivo.

Aclarubicin↗

PubMed1992

[Anti-carcinogenic and anti-promoting effects of retinoid R8605].

R8605 belongs to the third generation retinoid and was found during the systematic screening of cancer chemopreventive agents in our institute. Based on the theory of multistage carcinogenesis, the anti-carcinogenic and anti-promoting effects of R8605 as well as its possible anti-promoting mechanisms were studied. Experiments proved that R8605 (50 mg/kg and 25 mg/kg, i.g.) significantly inhibited the growth of skin papillomas induced by 7, 12-dimethylbenz[a]anthracene and croton oil in mice and exhibited a potent anti-promoting action. In addition, R8605 (50 mg/kg and 25 mg/kg, i.g.) strongly inhibited the induction of ornithine decarboxylase (ODC) activity of mouse skin epidermis by croton oil. At a dose of 100 mg/kg of R8605 (i.g.) croton oil-induced ear edema in mice was suppressed. These results suggest that the anti-promoting effect of R8605 might be associated with its anti-inflammatory action and its inhibitory effect on ODC activity.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1992

Growth inhibition and differentiation of promyelocytic cells (HL-60) induced by BC-4, an active principle from Boswellia carterii Birdw.

The induction of cell differentiation and growth inhibition of HL-60 cells by Bc-4, an active principle from Boswellia carterii, was studied in vitro and in vivo. The proliferation of HL-60 cells was found to be inhibited by Bc-4 at a concentration of 5-10 micrograms/ml. Under the action of Bc-4, the acid phosphatase and NBT reduction activities in HL-60 cells were increased, and phagocytosis of cells was also induced. All these activities were concentration dependent. The HL-60 cells were induced by Bc-4 to differentiate into more mature cells morphologically. The in vivo growth of HL-60 cells in mouse subrenal capsules (SRC) and in diffusion chambers inoculated into mice was inhibited by Bc-4 at a dose of 50 mg/kg. The morphology of HL-60 cells treated by Bc-4 in diffusion chambers exhibited characteristics of mature granulocytic cells.

Animals↗

PubMed1991

A research for the relationship between human papillomavirus and human uterine cervical carcinoma. I. The identification of viral genome and subgenomic sequences in biopsies of Chinese patients.

Biopsies from 318 cases with squamous cell carcinoma of the uterine cervix, 48 with cervical and vulvar condylomata, 14 with cervical intraepithelial neoplasia (CIN), 34 with chronic cervicitis and 24 with normal cervical epithelium were collected from different geographic regions with different cervical cancer mortalities. The DNA.DNA dot-blot and Southern blot hybridization results show that there is a close relationship between HPV-16 and the uterine cervical squamous cell carcinoma in China. One very interesting observation is that the finding of HPV-16-homologous DNA differs significantly among five geographic regions, and corresponds with the mortalities from cervical cancer of these five regions. HPV-11 was found mainly in benign lesions. The rate of detection of HPV-16 in Chinese women increased from 8.3% in normal cervical epithelium to 20% in chronic cervicitis, 28% in cervical condyloma, 50% in CIN and 60.4% in cervical cancer. It is suggested that HPV-16 infection may be an etiological factor in the development of human cervical carcinoma. From the results of Southern blot hybridization, it appeared that HPV-16 DNA had been integrated into the genome of the host cell in cervical cancer. Whereas the HPV-16 DNA sequence was only present as an episome in normal cervical epithelium and cervical benign lesions. The rate of occurrence of E6-E7 genes is the highest (88.9%) compared with that of other subgenomic fragments of HPV-16 in specimens of human cervical cancer in China. This implies that E6 and E7 may be the oncogenic genes of HPV-16 and play an important role in the carcinogenesis of human cervical epithelial cells. The amplification and rearrangement of the c-myc protooncogene are closely associated with the occurrence of cervical cancer. The results presented here revealed that the activated c-myc oncogene may cooperate with HPV-16 in the carcinogenic processes.

Biopsy↗

PubMed1991

[Delayed gastric emptying in diabetes mellitus].

Function of gastric motility was studied in thirty one diabetes mellitus patients by testing gastric emptying time (GET). The test was performed by giving patients food labelled with 99mTc. The results showed that GET in patients with diabetes mellitus was significantly delayed as compared with that in the controls (P less than 0.001). 15 among the 31 diabetic patients had delayed GET, accounting for 48.4%. There was no difference in age, duration of the disease, treatment regimen and microvascular complications between patients with delayed GET and those with normal GET. The only difference was the obviously increased incidence of autonomic nerve dysfunction in the former group of patients (P less than 0.05). We concluded that the incidence of delayed gastric emptying time was higher in diabetic patients with autonomic neuropathy.

Adult↗

PubMed1991

[Pharmacological studies of N-4-(hydroxycarbophenyl) retinamide].

Our studies show that the growth of transplantable chondrosarcoma in rats is inhibited significantly by N-4-(hydroxycarbophenyl) retinamide (RII) at a dosage of 50 mg/kg. RII show a weak ability to induce the differentiation of HL-60 cells at a concentration of 1 umol/L. However, most of the HL-60 cells were induced to differentiate along granulocyte lineage after exposure to RII (1 mumol/L) and S86019 (10 micrograms/ml). Flow cytometry studies indicated that the majority of HL-60 cells were arrested in G1 phase by RII plus S86019. Northern blot analysis clearly demonstrated that c-myc expression was inhibited after treating HL-60 cells with RII plus S86019 for 12 hours. Moreover, thymidylate synthetase mRNA transcription was inhibited in those differentiated cells.

Animals↗

PubMed1990

Prolactin secretion in myotonic dystrophy.

In order to evaluate prolactin secretion in females with myotonic dystrophy (MD) prolactin responses to TRH, metoclopramide and bromocriptine were studied in 13 women with myotonic dystrophy (10 normoprolactinaemic and 3 hyperprolactinaemic) and 8 healthy women. Following TRH administration mean maximal net increase was significantly higher in a group of normoprolactinaemic patients with MD in comparison to controls (p less than 0.05). In three patients with increased basal prolactin levels an exaggerated prolactin response to TRH has been observed. Normal prolactin response in a group of normoprolactinaemic as well as in hyperprolactinaemic patients have been observed following metoclopramide bolus injection. Following bromocriptine administration, maximal net decrease in prolactin levels has been found to be greater in normoprolactinaemic patients compared to healthy subjects, although the difference was statistically insignificant. The suppressive action of bromocriptine was more pronounced in patients with hyperprolactinaemia. Those results showed that there is some derangement in prolactin secretion in myotonic dystrophy leading to increased prolactin levels in some patients. Although the mechanism of this derangement has not been clarified yet it seems that it is not mediated via dopaminergic receptors.

Adult↗

PubMed1990

Studies on medicamentous inhibitory therapy for esophageal precancerous lesions--3- and 5-year inhibitory effects of antitumor-B, retinamide and riboflavin.

Since 1983, we have been conducting inhibitory therapy for precancerous lesions of the esophagus in two regions of Henan Province considered high-risk areas of esophageal carcinoma. Our goal was to effect a 50% reduction in the canceration rate of marked esophageal dysplasia. By means of a cytological survey, 2531 cases of marked esophageal dysplasia and 3393 cases of mild esophageal dysplasia were selected. The former were randomly divided into 3 groups for antitumor-B (ATB, a mixture of Chinese herbs), retinamide (4-ethoxycarbophenylretinamide) and placebo treatment respectively, and the latter into 2 groups treated with riboflavin and placebo respectively. Treatment was continued for 3 or 5 years (administration rate greater than 90% in all groups) and esophageal cytology reexamined (reexamination rates were 94.1% and 92.5% respectively). Our results were as follows: 1) ATB 3- and 5-year subjects saw the canceration rate of marked esophageal dysplasia drop by 52.2% and 47.3% respectively as compared to control (P less than 0.01). 2) Retinamide lowered the canceration rate by 37.3% after a 3-year treatment period, with this reduction reaching 43.2% after an additional 2 years of treatment with increased dosages (P less than 0.05, P less than 0.01). 3) In the riboflavin group, the canceration rate of mild esophageal dysplasia was reduced by 22.2% and 34.8% after 3 and 5 years of treatment respectively, but these differences were not statistically significant. The above results verify the efficacy of medicamentous inhibitory therapy for esophageal precancerous lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1990

[Influence of culture conditions on the growth of murine bone marrow stromal colony-forming cells (CFU-f) in vitro].

Several factors which may influence the colony-forming efficiency of mouse CFU-f, including media, culture dishes, mouse strains, and O2 concentrations in the incubator were tested. Among them, the O2 concentration was found to be the most important factor, when a mixed gas consisting of 5% O2, 5% CO2 and 90% N2 was used to replace the usual 5% CO2 in air, the colony-forming efficiency of CFU-f increased markedly and the influence of other factors on cell growth diminished. Although the use of a lit candle to consume O2 in the air provided good conditions for colony formation of several tumor cell lines in soft agar, it is not suitable for the growth of CFU-f.

Animals↗

PubMed1990

[Anti-tumor effect of hernandezine and other components extracted from Thalictrum glandulosissimum].

The total alkaloids of T. glandulosissimum and its main component hernandezine were found to be effective for treatment of mice bearing P388 leukemia, S180 ascites and C26 colon cancer. Although hernandezine inhibited the growth of mouse L1210 cells and human oral cancer KB cells in vitro markedly, its inhibitory effect on normal hemopoietic progenitor cells (CFU-GM) in mice was relatively low. Preliminary results showed that hernandezine blocked cell-cycle transfer from G1 to S phase, and its cytocidal action might be cell cycle specific. In addition, two other components, thalidezine and isothalidezine, isolated from the same plant exerted similar inhibitory effect on L1210 cells.

Alkaloids↗

PubMed1989

[Cytocidal action of homoharringtonine on L1210 cells in vitro].

The proliferation of L 1210 cells ceased rapidly after they were exposed to homoharringtonine (HH) 1 microgram/ml during exponential growth phase. However, 25.3% of the cells were still able to form colonies in soft agar if HH was removed after 24 h of incubation (the colony-forming efficiency for control cells was 62.5%). The clonogenic cells survived from the treatment were still sensitive to HH-continuous exposure. The IC50 of the treated and control cells were 15 and 20 ng/ml, respectively. Yet, the sensitivity of the treated cells to cytarabine decreased enormously. For instance, the survival rate of HH-treated cells remained at 100% level after they were exposed to cytarabine 4-8 micrograms/ml for 1 h, but only 40% control cells survived from the same treatment. When cells were continuously exposed to HH 0.4 micrograms/ml, the colony-forming efficiency decreased exponentially as a function of exposure time. The T1/2 of the clonogenic cells was about 18 h. The DNA contents in L 1210 cells was measured with a flow-cytometer. The results showed that the cell-cycle progress in all cells was interrupted by HH, regardless which phase they belonged to. So the cells seemed to be in a "frozen" state and the histogram unchanged.

Alkaloids↗