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Biomedical subjects

C W Chi

Publications and source records attributed to C W Chi.

At least 127 records · Page 7Linked to original sources
PubMed1991

Lung deposits of lipiodol in normal and cirrhotic rats.

The distribution of Lipiodol in the liver and lungs following arterial or portal injection was studied in normal (n = 55) and cirrhotic rats (n = 20). Using magnified xeroradiography and radioisotope labeled tracers, it was found that Lipiodol was deposited mainly in the liver and lung after either arterial or portal administration. In control rats after arterial injection, deposits in the lung peaked after 2 hours and gradually declined over 48 hours; whereas after portal injection, the deposit steadily increased for 48 hours. Twenty-five percent of cirrhotic rats demonstrated a Lipiodol-induced military pattern in the lung. An increased number of portosystemic shunts in cirrhotic rats was also noted. These results suggest that cirrhosis of the liver may be a potential risk factor for developing pulmonary complications after Lipiodol administration.

Animals↗
PubMed1990

Sex hormone receptors in gastric cancer.

Gastric adenocarcinoma that originates from mucosal tissue invades submucosa, muscle, and serosa in different stages. The level of progesterone receptors (PgR), estrogen receptors (ER), and androgen receptors (AdR) in the superficial part of gastric cancer tissues (CAs) from 16 patients was determined and compared with that of the corresponding normal gastric mucosal tissues (NLm). There were PgR in all CAs (100%) with values that ranged from 20.5 to 548.4 fmol/mg protein. Eight CAs (50%) had ER values that ranged from 6.8 to 325.1 fmol/mg protein. AdR was found in two CAs with values of 14.7 and 16.4 fmol/mg protein. In NLm, 15 (93.8%) had PgR values that ranged from 7.3 to 473.2 fmol/mg protein and ten (62.5%) had ER values that ranged from 0.9 to 87.9 fmol/mg protein. AdR were present in two NLm with values of 1.5 and 73.5 fmol/mg protein. There was no statistical difference in levels of PgR and ER between CAs and NLm. There were PgR in all gastric cancers and in 93.8% of NLm. The results suggest that gastric mucosa may be the target tissues for progesterone action. Furthermore, the lack of correlation between the levels of ER and PgR in gastric cancer tissue suggests that the PgR in gastric cancers are probably estrogen independent.

Adenocarcinoma↗
PubMed1990

Elevation of facilitated glucose-transporter messenger RNA in human hepatocellular carcinoma.

Complementary DNA of a rat brain glucose transporter gene was used to examine the expression of glucose-transporter messenger RNA in paired human hepatocellular carcinomas and adjacent nontumorous liver tissues, as well as in human hepatoma cell lines and human fetal liver samples. High expression of a major 2.8-kilobase glucose-transporter transcript was seen in all hepatoma cell lines and fetal liver samples examined, whereas a much lower level of expression was observed in liver tissues. When pairs of liver tissues were examined, elevation of glucose-transporter RNA levels was observed in most of the hepatocellular carcinoma tissues examined.

Animals↗
PubMed1990

Tropic effect of dexamethasone on goldfish melanocytoma cells: induction of calcium-dependent but protein synthesis-independent morphological changes.

Treatment of melanocytoma cells of goldfish origin with dexamethasone leads to rapid morphological changes, flattening of cell body and extension of dendrites. This effect is independent of protein synthesis but requires the presence of extracellular calcium, indicating that it is a "tropic effect" distinct from the typical "trophic effects" of steroid hormones that involve de novo protein synthesis.

Animals↗
PubMed1990

Isolation and nucleotide sequence determination of a gene encoding a heat-stable enterotoxin of Escherichia coli.

An enterotoxin-producing strain of E. coli has been isolated from an infant patient in Shanghai Children Hospital and the gene of its heat-stable enterotoxin has been cloned and sequenced. The pre-pro-STI was composed of 72 amino acid residues corresponding to the encoding of 216 base pairs. There was only one nucleotide difference in the pro-part between this STI gene and the STIb gene reported in the literature. A guanosine base in our STI gene was substituted for a cytosine base in STIb gene resulting in a replacement of proline by alanine. Hence, the STI genes from different human sources are highly conserved though mutagenesis still occurs.

Amino Acid Sequence↗
PubMed1990

[Construction of a computerized database for gastric cancer patients].

Gastric cancer is one of the most frequent malignant diseases in Taiwan. However, the result of treatment was poor. Since two years ago, we adopted the 'extended radical operation' for gastric cancer, in order to improve the post operative survival of patients with gastric cancer. For evaluating the results and prognosis, we used microcomputer and commercial software to design a computerized database for gastric cancer. The whole system includes three main operations. (1) Basic File Maintenance. (2) Data Analysis and Statistics. (3) Follow-up Data Managements. The operation is under Chinese system with pull-down menu and on-screen help. Rapid and accurate data analysis are the main advantages, and automatic plotting of data to bar/line chart is one of the characteristics by using this computerized database. Other characteristics include error-trapped function, item coding and data transformation.

Adult↗
PubMed1990

Report of a pilot study of intra-arterial injection of I-131 lipiodol for the treatment of hepatoma.

This pilot study in 10 hepatoma patients investigated the feasibility of using selective targeting of radioisotope (I-131) lipiodol in the treatment of hepatoma patients. Lipiodol is a contrast medium that selectively goes to hepatoma and remains there for a long period as compared with that in normal liver and other tissues. Lipiodol was labelled with I-131 and infused into the hepatoma via the hepatic artery. Selective targeting of I-131 to hepatoma was demonstrated with a radiation dose ratio (hepatoma to normal liver) of up to 25 to 1. The biodistribution data of I-131-lipiodol in this study also confirmed the selective targeting of the radioisotope (I-131) to the hepatoma. Tumor radiation dose up to 26,000 rads can be delivered by this method. The treatment results were encouraging. About 70% of hepatoma patients had response to the treatment with reduction of alpha-fetoprotein and decrease of hepatoma sizes. The overall median survival was 9 months (range 2-17 months). This treatment was simple, safe, effective, non-expensive and well tolerated by all patients without major side effects. The optimal dose, schedule, duration of this treatment are still under investigation.

Adult↗
PubMed1990

Studies on natural and modified peptide Trichosanthes trypsin inhibitors.

A peptide trypsin inhibitor was isolated and purified from the roots of Trichosanthes kirilowii (a Chinese medical herb) by using immobilized anhydro-trypsin affinity chromatography and HPLC C18 column reverse chromatography. It contains two major components, both consisting of 27 amino acid residues with three pairs of disulfide bonds. The sequence determination indicated that the difference between them is only in the ninth position, being Gln and Lys, respectively. The peptide bond of the inhibitor reactive site Arg-Ile (3-4) is easy to cleave at low pH by trypsin, resulting in a modified inhibitor. It might be the smallest naturally occurring protein inhibitor so far known. The modification reaction of the Trichosanthes inhibitor with trypsin is similar to the catalytic enzyme-substrate reaction. The dissociation constant of the modified inhibitor with trypsin is around fourfold that of the natural inhibitor.

Amino Acid Sequence↗
PubMed1989

Content of glucocorticoid receptor and arginase in gastric cancer and normal gastric mucosal tissues.

The content of glucocorticoid receptor (GR) and arginase in human gastric cancer and the corresponding normal gastric mucosal tissues was determined. Among the 25 patients studied, the GR content in gastric cancer tissues was 33.2 +/- 10.2 fmol/mg protein versus 7.6 +/- 3.4 fmol/mg protein in gastric mucosal tissues. This difference is statistically significant (P less than 0.005). Of the 25 paired samples, 19 cancer tissues contained GR, whereas only seven of the normal mucosal tissues had GR. The level of arginase in gastric cancer tissues in 19 patients was assayed, it was 26.6 +/- 4.2 ng/mg protein which is also significantly higher than that in normal gastric mucosal tissues (13.5 +/- 1.8 ng/mg protein) (P less than 0.005). Since glucocorticoids and arginase are potent immune suppressive agents, the increased level of GR and arginase in gastric cancer tissue suggest that these glucocorticoid-related factors in gastric cancer tissue may play a partial role in regulating cellular immunity.

Aged↗
PubMed1989

Isolation and characterization of cortisol-sensitive and -resistant P1798 mouse lymphosarcoma cell lines.

Three cell lines have been isolated and characterized from the P1798 mouse lymphosarcoma. One line, derived from a glucocorticoid-resistant tumor, was glucocorticoid-resistant in vitro. The other two cell lines, derived from glucocorticoid-sensitive and -resistant parental tumors, respectively, were shown to be glucocorticoid-sensitive in vitro. The glucocorticoid receptor from all three cell lines bound glucocorticoid with similar affinity and capacity. However, based on Sephacryl S-300 gel filtration, the glucocorticoid receptor from the resistant cell line was smaller than that of the two sensitive cell lines. Moreover, the glucocorticoid receptor from the resistant cell line accumulated to a greater extent in the nucleus. This resistant cell line thus resembles the nti variant of the S49 lymphoma cell line. All three cell lines were tumorigenic and metastatic when reimplanted into mice, contained the normal mouse diploid complement of 40 chromosomes and exhibited the same responsiveness to cortisol in vivo as they did in vitro. It is concluded that the ready passage of these cell lines in vitro or in vivo and the presence of the small receptor in the resistant line should make them excellent model systems for the study of glucocorticoid resistance.

Animals↗
PubMed1989

Steroid hormone receptors in meningiomas of Chinese patients.

Meningioma is a hormone-related intracranial tumor. Brain tumor samples were collected from 32 Chinese patients, 20 of whom had meningiomas. Estrogen receptors were present in 6 of 17 meningiomas, 1 hemangioblastoma, 1 gemistocytic astrocytoma, and 1 neurilemoma. Of the 26 samples assayed for progesterone receptors, measurable bindings were found in 14 of 17 meningiomas, 1 of 2 astrocytomas, 1 malignant lymphoma, 1 hemangioblastoma, 1 ganglioglioma, 1 glioblastoma multiforme, 1 anaplastic ependymoma, 1 small cell sarcoma, and 1 neurilemoma. Androgen receptors were found in 8 of 19 meningiomas, but not in the 11 other brain tumors examined. Measurable glucocorticoid receptors were found in 15 of 19 meningiomas, 1 malignant lymphoma, 1 hemangioblastoma, 2 craniopharyngiomas, 1 neurilemoma, 1 of 2 glioblastomas, and 1 of 2 astrocytomas. Of the 10 samples examined for tyrosine aminotransferase activity, measurable enzyme activity was found in 7 of the 8 meningiomas, but not in the single hemangioblastoma nor in the single craniopharyngioma. In accordance with other published studies, the results from this study also suggest that the growth of meningiomas may be regulated by hormones, and that the role steroid hormones and their receptors play in the meningioma is worthy of further investigation.

Adult↗
PubMed1989

The inhibition of the enzymic activity of blood coagulation and fibrinolytic serine proteases by a new leupeptin-like inhibitor, and its structural analogues, isolated from Streptomyces griseus.

A group of leupeptin analogues was found in Streptomyces griseus strain 254, isolated from a soil sample from Fujian Province, China. The inhibitors excreted in the culture filtrate were purified by adsorption on macroporous resin, followed by sequential ion exchange chromatography on DEAE-52 cellulose, CM-32 cellulose and affinity chromatography with immobilized trypsin. The preparation thus obtained was further purified by preparative HPLC. Several major components were found and characterized, which possessed different inhibitory properties toward trypsin. Based upon amino acid and mass spectrophotometric analysis, these peptides were placed in four major structural categories, viz., R-Val-Val-argininal, R-Leu-Leu-argininal, R-Ile-Ile-argininal and R-Thr-Thr-argininal, this latter component representing a newly identified leupeptin analogue. The structural variability of the R-group was partly responsible for the multiplicity of the peaks obtained with HPLC. All peptides displayed varying degrees of inhibitory activity toward proteases involved in blood coagulation and fibrinolysis, including plasmin, factor Xa, activated protein C and thrombin. Among these peptide inhibitors, the molecule containing threonine showed the strongest inhibitory activity.

Amino Acid Sequence↗
PubMed1989

Analysis of monoamines in the cerebrospinal fluid of Chinese patients with neurological diseases.

Levels of dopamine (DA), 3-methoxy-4-hydroxy-phenylacetic acid (HVA), 5-hydroxy-indoleacetic acid (HIAA), 5-hydroxytryptamine (HT), 5-hydroxytryptophan (HTP), and 3, 4-dihydroxyphenylalanine (DOPA) in cerebrospinal fluids (CSF) of twenty-four Chinese with or without neurological diseases were determined simultaneously. The level of HIAA in the CSF of myelopathy-spondylosis patients and the level of DA in CSF of the myelopathy-tumor patients were higher than that of the control. No difference in levels of monoamines and their metabolites was observed between the control and patients with dementia.

Adolescent↗
PubMed1988

Glucocorticoid receptors in hepatocellular carcinoma and adjacent liver tissue.

Glucocorticoid and progesterone receptors, tyrosine aminotransferase, gamma-glutamyltransferase and alpha-fetoprotein levels were determined in human hepatocellular carcinoma (HCC) and adjacent liver tissues. Glucocorticoid receptor was present in seven of ten HCC samples, values ranged from 1.9 to 66.8 fmol/mg protein. Progesterone receptor was present in two of ten HCC samples with values of 1.7 and 7.2 fmol/mg protein, respectively. In the adjacent liver tissues, no measurable progesterone receptor was found and only one sample had glucocorticoid receptor with a value of 3.0 fmol/mg protein. The increase of glucocorticoid receptor in HCC samples was coincident with a decreased level of tyrosine aminotransferase and an increased level of gamma-glutamyltransferase. No correlation was found among glucocorticoid receptor level, serum or tissue alpha-fetoprotein levels. The presence of glucocorticoid receptors in HCC suggest that hormones may play an important role in the formation of hepatoma, and hormonal therapy may be useful for patients with HCC.

Carcinoma, Hepatocellular↗
PubMed1988

Combined therapy with 5-azacytidine and hydrocortisone in glucocorticoid-sensitive and -resistant mouse P1798 lymphosarcoma.

Experiments were undertaken to test the hypothesis that 5-azacytidine (AZA) treatment might make the glucocorticoid-resistant line of the mouse P1798 lymphosarcoma sensitive to cortisol. A modest (30%), though significant, effect in making cells cortisol sensitive was observed. Moreover, AZA enhanced tumor growth inhibition by cortisol in the corresponding sensitive line. The AZA alone was cytostatic, but it had no effect on DNA synthesis. The drug did not alter cytoplasmic glucocorticoid receptor levels or affinity, but nuclear levels were increased in the sensitive tumor. Results suggest that glucocorticoid resistance may be partially reversible and that the effect of AZA may be at the gene-expression level.

Animals↗
PubMed1988

Monoclonal antibodies specific for human IgE and their clinical applications.

By applying the hybridoma technique, two mouse anti-human Immunoglobulin E (IgE) monoclonal antibodies, designated as E17-58 and E20-62, were generated and characterized. E17-58 was a murine IgG2b with an affinity constant of 4 x 10(8)l/mole. E20-62 was a murine IgG1 with an affinity constant of 1 x 10(8) l/mole. These two antibodies recognized different antigenic determinants specific to the IgE molecule. They were used in combination to quantify the total serum IgE level of forty-nine persons. Data obtained correlated highly with that obtained by using the Pharmacia PRIST Kit (r = 0.91). E17-58 was also used to detect the anti-Aspergillus specific IgE of twenty-one atopic patients by a radioimmunosorbent test. The positive rate detected correlated very well with the skin test (p less than 0.05). In addition, in the Western blot system, these monoclonal antibodies were capable of identifying IgE binding components of crude allergen extracts. Extracts from pollens of Bermuda grass were evaluated, and a new major allergenic component with a molecular weight of 40 kd was identified.

Animals↗
PubMed1987

The effects of arginase on neoplasm. I. The role of arginase in the immunosuppressive effects of extract from gastric cancer.

Arginase, a potent immune inhibitor, is studied in gastric cancer for its possible role in immunosuppression. Aqueous extracts (n = 12) from gastric cancer tissue inhibited PHA-induced lymphocyte proliferation more than those from normal gastric mucosal tissues (p less than 0.05). The inhibition was not due to cytotoxic effect of the extracts. Gastric arginase was isolated from gastric extracts by an affinity column conjugated with an anti-arginase antibody. The arginase from both normal and cancer gastric tissues strongly inhibited lymphocyte proliferation. By using enzyme-immunoassay, the arginase contents in cancer tissues were determined and showed 3 times as much as that in normal gastric mucosal tissues (n = 14) (p less than 0.005). The increased arginase content in cancer tissue was further confirmed by immunohistochemistry study. Arginase exists abundantly amounts in the cytoplasm of cancer cells, much more than that of normal cells (n = 30). It is conceivable that the depressed cellular immunity in gastric cancer patients might be partly due to the abundant amount of arginase in cancer cells.

Arginase↗