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Biomedical subjects

C J Wang

Publications and source records attributed to C J Wang.

At least 163 records · Page 9Linked to original sources

Epidural abscess presented with psychiatric symptoms.

Cranial epidural abscesses are unusual in neurosurgical practice. Mostly they are secondary to skull bone osteomyelitis of foreign body implantation as a result of trauma, or infection of paranasal sinus, otitis, and mastoiditis in adults or late adolescents. The purulent inflammatory process of the epidural abscess, thrombophlebitis of the venous drainage, septic thrombosis, direct extension into the orbit, carvenous sinus, superior orbital fissure give the epidural abscess a high mortality and morbidity. We present an interesting case, who has had psychiatric symptoms such as bizarre behavior, auditory and visual hallucination for about two years. Incidental brain computed tomograms, to exclude the organic-somatic disorder, revealed a huge brain abscess. Emergent surgical intervention was carried out and the episodes of talking to himself and auditory hallucination subsided. The removal of the epidural abscess eliminated the symptoms and cured the patient. All the right amygdata, entorhinal area, cingulate gyrus, hippocampus and parahippocampal gyrus of this patient were compressed by the huge abscess. All these structures belonged to limbic system. Diseases involving the limb system may cause emotional disturbances, such as delusions, illusions and hallucinations, emotional lability, pathological laughing and crying, rage reaction and aggression, apathy and placidity, even endogenous fear, anxiety, depression and euphoria. Dramatic improvement of the patient was found after surgical removal of the abscess. We highlight this interesting case for it will undoubtedly bring together a large cooperation of psychiatrists, neurologists and neurosurgeons.

Abscess↗

Hepatotoxicity of 1,3,5-trinitro-2-acetyl pyrrole derived from nitrosation of Maillard reaction product in BALB/C mouse.

1,3,5-Trinitro-2-acetyl pyrrole (TNAP) is a product derived from the reaction of 2-acetyl pyrrole with nitrite in the model of Maillard browning systems. This compound is moderately mutagenic to the Salmonella strains TA98 and TA100 and is markedly cytotoxic to mouse C3H10T1/2 cells. Experiments are performed to investigate the effects of TNAP on the hepatic toxicity in mouse. Male BALB/C mice were subjected to a dose of 7.2 mg/kg body weight twice a week by i.p. injection for 24 weeks, then followed by a feeding diet for 21 weeks. TNAP-treated mice showed an increase in mortality and time-dependent appearance of lesions in the liver. TNAP is hepatotoxic as demonstrated by a marked increase in the activities of serum alanine transaminase (ALT) and aspartic transaminase (AST). TNAP-related lesions observed histologically in mice, included hapatic atrophy, mild fatty metamorphosis with multilocular cysts in the liver. In conclusion, TNAP was considered to be a toxic compound in mice as evidenced by increased incidences of mortality, and lesions of liver.

Alanine Transaminase↗

Hibiscus protocatechuic acid protects against oxidative damage induced by tert-butylhydroperoxide in rat primary hepatocytes.

Hibiscus protocatechuic acid (PCA), a simple phenolic compound isolated from Hibiscus sabdariffa L., was studied for its protective effects against oxidative damage induced by tert-butylhydroperoxide (t-BHP) in a primary culture of rat hepatocytes. It had been reported that exposure of isolated hepatocytes to t-BHP results in leakage of lactate dehydrogenase (LDH) and alanine transaminase (ALT), peroxidation of cellular lipids, and depolarization of mitochondria. The present investigations showed that PCA at concentrations of 0.05 mg/ml and 0.10 mg/ml significantly decreased the leakage of LDH (P < 0.01) and ALT (P < 0.05 and P < 0.01) and the formation of malondialdehyde (MDA; P < 0.05 and P < 0.01) induced by 30-min treatment with t-BHP (1.5 mM) in primary cultured rat hepatocytes. PCA also attenuated t-BHP (0.10 mM) induced mitochondrial depolarization as determined by a retention test of rhodamine 123 and DNA repair synthesis as evidenced by unscheduled DNA synthesis (UDS). In addition, PCA exhibited an effective ability to quench 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH). In conclusion, PCA demonstrated protective effects against cytotoxicity and genotoxicity of hepatocytes induced by t-BHP. One of mechanisms of PCA's protective effect may be associated with its property of scavenging free radicals.

Animals↗

N-linked glycosylation of hepatitis B surface antigens is involved but not essential in the assembly of hepatitis delta virus.

Hepatitis delta virus (HDV) is a defective virus requiring the hepatitis B virus (HBV) to provide hepatitis B surface antigens as the envelope protein. The hepatitis B surface antigens are posttranslationally modified by N-linked glycosylation, and its significance in HDV assembly was investigated with a cotransfection system using human hepatoma cell line Huh-7. After the N-linked glycosylation of HBsAg was blocked by tunicamycin treatment, the packaging of HDV in the culture system could be suppressed to a level as low as 5-10% of the untreated control. The extent of inhibition correlated with the increased concentrations of tunicamycin. In contrast, the loss of HBsAg glycosylation did not affect the efficiency of assembly of HBV particles. When the N-linked glycosylation site of small HBsAg at amino acid 146 was mutated from asparagine to glutamine, the mutant HBsAg packaged only a modest amount of HDV particles. The quantity and kinetics of formation of HDV particles in culture system were reduced by the depletion of HBsAg glycosylation. Therefore HDV, similar to influenza and vesicular stomatitis viruses, depends on glycosylation of the envelope proteins as a signal for envelope protein maturation and for virion formation.

Amino Acid Sequence↗

Topographic distribution of inguinal lymph nodes metastasis: significance in determination of treatment margin for elective inguinal lymph nodes irradiation of low pelvic tumors.

PURPOSE: To study the distribution of gross inguinal lymph node metastasis and, in particular, its correlation with major pelvic bony structures on a simulation film. METHODS AND MATERIALS: Thirty-seven cases of low pelvic tumors having gross inguinal lymph node metastasis that were treated with radiation therapy between November 1987 and December 1992 were segregated for study. The patient's nodes were palpated and marked with lead wire before the simulation film was assumed to be the origin of the previously uninfested node. A total of 84 such labeled nodes was taken. The geometric center of the usually round or elliptical node on the film was obtained from these 37 cases. These centers were transferred to and mapped collectively on a new simulation film showing major pelvic bony structures of left hemipelvis and upper femur. RESULTS: Distribution of gross inguinal lymph nodes was found confined to the following area, as related to major pelvic bony structure: laterally, just abutting the tangential line that passes through lateral border of the femoral head; medially: 3 cm away from the body's midline axis; superiorly: 1 cm below the line that joins both upper borders of the femoral head; inferiorly: 2.5 cm below the low borders of ischial tuberosity. According to this rectangular boundary, three nodes were out of the field, nine nodes near the border less than 1 cm margin. This area adequately covered 86% (72 of 84) of the studied nodes. CONCLUSION: Distribution study is important in determining the treatment margin. In general, an additional 1-2 cm beyond the area described above is the recommended treatment margin for elective inguinal lymph nodes irradiation with high confidence level of coverage.

Adult↗

Promotion of colon carcinogenesis through increasing lipid peroxidation induced in rats by a high cholesterol diet.

To examine the influence of hypercholesteremia on 1,2-dimethylhydrazine (DMH)-induced rat colon cancer, Sprague-Dawley rats received dietary cholesterol (CH, 0-2%) and cholic acid (CA, 0.25%) with or without DMH (20 mg/kg, s.c. injection) for 18 weeks. The rats receiving dietary cholesterol and cholic acid all significantly increased total serum cholesterol and lipids but only a high cholesterol diet (2% CH plus 0.25% CA) decreased the activity of glutathione peroxidase (GSH-Px) and increased the formation of peroxides in the colon (P < 0.01). The rats that received the combination of DMH and high cholesterol diet enhanced these effects. At the end of the experiment, the diet group administered DMH and high cholesterol (2% CH plus 0.25% CA) developed colon adenoma at 50% of incidence in pathological examination, but no colon adenoma formed in the rats treated with high cholesterol alone. It is supposed that a non-carcinogenic agent like cholesterol may potentiate the carcinogenicity of DMH in rats via an increase of lipid peroxidation and decrease in the activity of peroxidase in the target organ.

1,2-Dimethylhydrazine↗

Inhibition of protein kinase C and proto-oncogene expression by crocetin in NIH/3T3 cells.

Crocetin, a carotenoid isolated from the seeds of Gardenia jasminoides, was found to be a potent inhibitor of tumor promotion induced by 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse skin. When mouse fibroblast NIH/3T3 cells were treated with TPA alone, protein kinase C (PKC) translocated from the cytosolic fraction to the particulate fraction. Pretreatment with 60 and 120 microM crocetin for 15 min inhibited the TPA-induced PKC activity in the particulate fraction by 50% and 66%, respectively, but did not affect the level of PKC protein. Crocetin also reduced the level of TPA-stimulated phosphorylation of cellular proteins. Cells pretreated with crocetin (120 microM) had 55% less PKC [3H]phorbol dibutyrate-binding capacity. Suppression of TPA (100 ng/mL)-induced c-jun and c-fos gene expression was also observed in the mouse fibroblast cells pretreated with crocetin (30, 60, and 120 microM). Our results provided a basis for understanding the inhibitory effect of crocetin on TPA-mediated tumor promotion.

3T3 Cells↗

L ferritin accumulation in macrophages infiltrating the lung during rat Angiostrongylus cantonensis infection.

A 22-kDa protein was increased quantitatively, as measured by sodium dodecyl sulfate-polyacrylamide gel electrophoresis techniques, in lung microsomes prepared from Angiostrongylus cantonensis-infected rats. However, it was almost absent in normal rats. The protein was purified by sequential chromatography on Superdex 200 columns and identified chemically and immunologically as ferritin. Using isoelectric focusing and anion exchange chromatography, it was identified as L ferritin. Distribution of this 22-kDa protein in the lung tissue of A. cantonensis-infected rate was studied by immunocytochemistry. Positively stained cells were mainly infiltrated macrophages. Our results suggest that L ferritin accumulation in the macrophages may be related to the proliferation of connective tissue elements and the inflammatory response to A. cantonensis dwelling in the pulmonary arteries of the rat.

Angiostrongylus cantonensis↗

Inhibitory effect of atractylon on tert-butyl hydroperoxide induced DNA damage and hepatic toxicity in rat hepatocytes.

Atractylon, a main sesquiterpenic constituent of Atractylodes rhizomes, was studied for the mechanism of its inhibitory effects on the tert-butyl hydroperoxide (t-BHP)-induced cytotoxicity and lipid peroxidation in primary culture of rat hepatocytes. In the preliminary study, atractylon showed an effective antioxidant property tested by its capacity for quenching 1,1-diphenyl-2-picrylhydrazyl radical (DPPH). Further investigations showed that atractylon at the concentrations of 0.01, 0.1 and 1.0 mg/ml decreased the formation of malondialdehyde (MDA), leakage of lactate dehydrogenase (LDH) and alanine aminotransferase (ALT) and repair synthesis of DNA induced by 30-min treatment of t-BHP (1.5 mM) in primary cultured rat hepatocytes. Addition of atractylon also attenuated the genotoxicity of t-BHP evaluated by unscheduled DNA synthesis. The sum of the results suggested that the protective effect of atractylon against oxidative stress induced by t-BHP is via its ability to quench free radicals.

Animals↗

Patterns of distant metastases in nasopharyngeal carcinoma.

The distant metastasis in nasopharyngeal carcinoma has remained the major cause of mortality and treatment failure despite better locoregional control of the disease in the past decades. Between 1987 and 1992, 125 out of 629 cases of nasopharyngeal carcinoma were found to have distant metastasis. The location of metastatic site, the timing and median survival were analyzed. The diagnosis of distant metastasis in the retrospective study was based on radiography, computed tomography, skeletal scintigraphy, abdominal sonography and pathology reports. The results showed that the frequencies of metastases were as follows: bone (75% of total metastatic patients), lung (46%), liver (38%), retroperitoneal lymph nodes (10%). Multiple organ involvement was high (57%). Most of the distant metastases (95%) occurred within 3 years after completion of radiotherapy, the first year (52%), the second year (23%) and the third year (20%). The median survival time from the discovery of distant metastasis was 11.2 months for bone metastasis, 16.3 months for pulmonary metastasis, and 3.2 months for hepatic metastasis. The results revealed that the skeletal system was the most common site of distant metastasis, followed by lung and liver. The incidence of retroperitoneal lymphadenopathy is higher than previous reports.

Adult↗

Human prolactinomas in cell culture: structure-function correlation and indication of early relapse.

Cell cultures of 7 micro- and 16 macroprolactinomas obtained from twenty-three patients (10 males and 13 females) by transsphenoidal adenomectomies were found to be capable of secreting hormones in vitro. Prolactin levels in the culture media were measured during the culture periods and showed that the high PRL levels in culture media may indicate early relapse. Morphological features of both micro- and macroprolactinomas in vitro resembled those of the original tumors. Most macroprolactinomas harbored densely-granulated cells, while most microprolactinomas sparsely-granulated cells. The cell culture techniques combined with morphological studies of prolactinomas allow further investigation of structure-function correlation in human prolactinomas.

Adolescent↗

Intrasellar meningiomas.

Two cases of intrasellar meningiomas with preoperative diagnosis of pituitary macroadenomas are presented. The preoperative hormonal studies revealed decreased serum hormonal levels with a slightly elevated prolactin level in both cases, which may have been due to the compression of the hypophyseal stalk. It is difficult to differentiate intrasellar meningiomas from pituitary tumors. Correct preoperative diagnosis depends on clinical picture, neuroimaging and endocrine studies. Surgically, the transsphenoidal approach provides a relatively safe route to the intrasellar meningiomas and satisfactory results.

Adenoma↗

Surgical management of TSH-secreting pituitary adenomas.

Two patients with hyperthyroidism due to a thyrotropin (TSH)-secreting pituitary tumor have been observed of a total of 172 patients (1.2%) with pituitary adenomas over a period of 10 years (1986-1995). The serum TSH elevated in spite of high thyroid hormone levels in these two patients. They underwent transsphenoidal adenomectomies to remove the TSH-secreting pituitary tumors with excellent results. Tumors secreting TSH are very rare and are less easily cured by surgery than other types of pituitary adenomas because of large size and invasive features. Our experience with these two patients suggested the importance of early diagnosis and surgery for successful treatment of TSH-secreting pituitary tumors.

Adenoma↗

Effect of bromocriptine on the sensitivity of pituitary tumor cells to radiation.

GH3 cells, a PRL-secreting rat pituitary tumor cell line, are sensitive to bromocriptine, and provide a useful model for the present studies. GH3 cells, in the presence or absence of 2.5 x 10(-5) M bromocriptine, were irradiated at doses ranging from 0 to 10 Gy. After irradiation the bromocriptine was washed out, cells were seeded at a density of 10,000 cells/ml, and growth curves were obtained by counting the cell number at weekly intervals for 1 month. Cell growth was inhibited by the radiation in a dose-dependent fashion, with complete inhibition of cell growth by 9 Gy. However, no protection against radiation damage was afforded by bromocriptine. These results might suggest that the combined therapies of tumor shrinkage by bromocriptine and stereotactic irradiation of the sella might be a useful clinical therapeutic strategy, particularly in patients with large tumors, severe hyperprolactinemia, and pre-existing hypopituitarism.

Animals↗

Crocetin protects against oxidative damage in rat primary hepatocytes.

Crocetin is a major component in the fruit of Gardenia jaminoides Ellis, a Chinese herbal medicine. Its protective action and mechanism against oxidative damage were investigated and mechanism against oxidative damage were investigated. Reactive oxygen species (ROS) were generated enzymatically in the xanthine-xanthine oxidase (X/XO 5 microM/0.01 u/ml) system and non-enzymatically in the paraquat (PQ 5 mM) system. Both systems increased leakage of lactate dehydrogenase (LDH) and alanine transaminase (ALT) in rat primary hepatocytes, but the hepatotoxicity was significantly suppressed on pretreatment with crocetin (10, 20 microM). Crocetin decreased formation of malondialdehyde (MDA) as an index of lipid peroxidation induced by ROS. The oxyradical generation by X/XO or PQ caused DNA damage evaluated with unscheduled DNA synthesis (UDS) in rat primary hepatocytes. The addition of crocetin decreased genotoxicity evaluated with UDS in both systems. The data showed that crocetin also inhibited the formation of superoxide anion in the X/XO system and bleached the free radical 1, 1-diphenyl-2- picrylhydrazyl (DPPH). The protective action of crocetin operated via quenching of the superoxide anion and/or free radical.

Animals↗

Determination of a cyclic guanine monophosphate phosphodiesterase inhibitor (SCH 51866) in rat serum using capillary zone electrophoresis.

A capillary zone electrophoretic (CZE) assay was developed for the determination of cis-5,6a,7,8,9,9a-hexahydro-2-[4-(trifluoromethyl)phenylmethyl]-5-methyl - cyclopent[4,5]imidazo[2,1-b]purin-4(3H)-one, SCH 51866 (I), a cyclic guanine monophosphate phosphodiesterase inhibitor, in rat serum using acetonitrile deproteination as a clean-up step before injection. The calibration curve was linear over a serum concentration range of 0.5 to 10 micrograms/ml serum with a correlation coefficient (r) > 0.99. The limit of quantitation (LOQ) was established at 0.5 micrograms/ml. Fifty microliters of serum were used for analysis, which allowed serial bleeding (8 samples) from a single rat to characterize the pharmacokinetic profile of I after either oral or intravenous drug administration. In traditional pharmacokinetic and toxicokinetic studies in rodents, one animal provides only one serum sample since 1 to 2 ml of sample volume is required for chromatographic analysis, resulting in the use of a large number of animals per study. This assay yields a significant reduction in the use of animals, hence providing a large reduction in resources and time in drug discovery and development.

3',5'-Cyclic-GMP Phosphodiesterases↗

Expression of thyroid hormone receptors in human pituitary tumor cells.

To understand the expression of thyroid hormone receptors (TRs) in various types of pituitary tumor cells, we performed the reverse transcription coupled to polymerase chain reaction (RT-PCR). Specimens of pituitary adenomas were obtained by transsphenoidal adenomectomies from 2 patients with acromegaly, 6 patients with prolactinoma, 3 patients with Cushing's disease, 2 patients with gonadotropin-secreting tumors, one patient with a TSH-secreting tumor, and 3 patients with non-functioning adenoma with no clinical evidence of pituitary hormone overproduction. Human thyroid hormone receptors beta 1 and alpha 1, alpha 2 (h-TR beta 1, alpha 1, alpha 2) are expressed in nonfunctioning adenomas; h-TR alpha 1 and beta 1 are specific for prolactinomas; h-TR beta 1 is involved in acromegalies and FSH-secreting tumors, while h-TR alpha 1, alpha 2, and beta 1 are not expressed in TSH-secreting and ACTH-secreting tumors. The results suggest that human thyroid hormone receptors are differentially expressed in human pituitary tumor cells, and our studies have shed new light on the understanding of the role of TRs in pituitary tumors.

Adenoma↗