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Biomedical subjects

X Sun

Publications and source records attributed to X Sun.

At least 433 records · Page 24Linked to original sources
PubMed1996

Spontaneous malignant transformation of fibrous dysplasia.

OBJECTIVE: To evaluate the clinical and radiological findings in diagnosing spontaneous malignant transformation of fibrous dysplasia. METHODS: Fifteen cases of sarcomatous transformation proved by operation and pathological examinations were found in a group of 356 patients with fibrous dysplasia, and their radiological manifestations were retrospectively studied. The 15 cases included 8 osteosarcomas, 5 fibrosarcomas and 2 chondrosarcomas. All the 15 patients were known to have long-standing fibrous dysplasia, but no radiation therapy was ever received. Eleven patients had polyostotic fibrous dysplasia and 4 had monostotic type. RESULTS: Malignant transformation most frequently occurs in the cystic expansive lesion of the long tubular bone. Pains, swelling and late appearance of a bony mass are the main clinical manifestations. The early radiological features of sarcomatous transformation in fibrous dysplasia are moth-eaten or cystic areas of osteolysis located in the involved bone. The cortical destruction and gradual formation of a soft tissue mass that contains tumor-bone are highly suspicious of osteosarcomatous transformation, while ring-like and spotty calcification in the tumor matrix is indicative of chondrosarcoma. Fibrosarcoma usually shows simple osteolytic destruction. CONCLUSIONS: According to the clinical radiological findings, patients of sarcomatous transformation can be detected in the early stage. These radiological findings may be used as a clue for differentiating various kinds of sarcomatous transformation.

Adult↗
PubMed1996

[Experimental studies on damage to acoustic organ in guinea pigs caused by imitated coal mining noise].

To study the damage to the hearing of miners under the shaft caused by noise and its recovery, an experiment with imitated noise was carried out in guinea pigs. The animals were divided into five groups with exposure to imitated underground noise of 117 dB (A) for one hour for one, two, four, eight and 16 days, respectively, and one control. Thresholds of cortex reaction and evoked electric reaction of brain stem were detected before and after exposure. And, ultrastructural changes in cochlear hair cells were observed by scanning and transmission electron microscopy. Results showed that exposed noise level and length since removing from exposure had significant effects on changes in hearing threshold. Damage to hearing was aggravated with prolonged exposure, to various extent, from changes in temporary threshold shift and permanent threshold shift to recovery from it after removing from exposure. Intracellular structural changes in internal and external hair cells and their injury deteriorated gradually with increase of exposure levels, at worst, to changes in epithelial plate, collapse of Corti's organ and vacuolation, edema and degeneration of cells. It suggests it is important to protect workers form exposure to noise.

Animals↗
PubMed1996

A molecular pathologic study on apoptosis in retinoblastoma and the mechanism of spontaneous regression in retinoblastoma.

OBJECTIVE: The present study was designed to prove the existence of apoptosis in retinoblastoma (Rb) and to determine the pathogenic mechanism of spontaneous regression of Rb as well as the relationship between them. METHODS: Qualitative morphological study on Rb was performed by means of light microscope, electron microscope and TdT mediated biotin-dUTP nick-end labeling (TUNEL). Quantitative study was performed by automatic image analysis technology (AIAT) stained with Feulgen reaction. RESULTS: The characteristic regressed area occurred in all 47 cases of Rb. Morphological changes observed within Rb closely resembled the apoptotic cell described by Kerr et al in 1972. Under electron microscope, details of apoptosis were observed in 7 cases of Rb: the morphological sequence of events occurred in and around the cell nucleus. The morphology of the TUNEL labeling Rb cell was various. TUNEL labeling showed more positive cells in regressed area, while fewer in advanced area. AIAT revealed that apoptosis index (AI) in regressed areas was higher than that in other areas of Rb, DNA average ploidy (DP) consisted with the histology grade of Rb, the degree of hyperdiploid (DH) in metastatic area was distinctly higher than that in other areas (P < 0.05). CONCLUSIONS 1. Morphologic evidence proved the existence of apoptosis, especially more in regressed area of Rb. 2. Apoptosis may participate in the spontaneous regression of Rb. Apoptosis contributed to the spontaneous regression of Rb. 3. Tumor growth parameters of Rb (AI, DP, DH) obtained by AIAT may be used as quantitative index for pathologic classification, the selection of clinical treatment and the prognostic evaluation.

Apoptosis↗
PubMed1996

[Quantitative analyses of DNA content and P53 gene product expression from epithelial lacrimal gland tumors].

OBJECTIVE: To investigate the significance of quantitative analyses of DNA content and P53 gene product expression which are applied for pathological diagnosis of epithelial lacrimal gland tumor. METHODS: Flow cytometry (FCM) and immunofluorescence staining technique were used to quantitatively measure the DNA content and expression of P53 gene product from 39 cases with epithelial lacrimal gland tumors. RESULTS: It is indicated that the pleomorphic adenomas still possess of the properties of DNA diploid of normal lacrimal gland cell, but malignant tumors are characterized by DNA aneuploidy. There is a significant difference in the content of expression of P53 gene product between pleomorphic adenomas and malignant tumors (P < 0.001). The content of expression of P53 gene product is positively correlated to the DNA content, and both are increasing with the reduction of tumor tissue differentiation. CONCLUSION: Quantitative analyses of DNA content and expression of P53 gene product may provide objective indexes for the pathological diagnosis of epithelial lacrimal gland tumor.

Adenoma, Pleomorphic↗
PubMed1996

[Automatic image analysis of argentophil protein granule quantitative measurement on nucleolus area of limbus epithelial neoplasms].

OBJECTIVE: To study the pathological diagnostic significance of argentophil protein (AgNOR) quantitative analysis at nucleolus area of limbus epithelial neoplasms. METHODS: Automatic image analysis system was used for argentophil protein granule measurement in the pathologic diagnosis of 45 cases with limbus epithelial neoplasms, including benign hyperplasia, atypical hyperplasia, carcinoma in situ and squamous cell carcinoma. RESULTS: In various lesions, there were the differences in the distributive pattern, size and area of AgNOR granules, which were closely related to the nature of the neoplasms (benign or malignant) and its cell differentiation. CONCLUSION: Automatic image analysis of AgNOR quantitative measurement on limbus epithelial neoplasms may indicate the proliferative activity and cell differentiation in various lesions, help to differentiate benign or malignant neoplasms and effectively enhance the level of pathologic diagnosis.

Carcinoma in Situ↗
PubMed1996

[Comparison of 4 extraction methods for antidotal granules of Coptis].

Four extraction methods for Antidotal Cranules of coptis were compared, with berberine, barcalin and gardenoside taken as the indexes. The result shows that the total contents of three components appear in the following order: semi-bionic extraction > semi-bionic extraction with precipitation with alcohol > extraction with water > extraction with water plus precipitation with alcohol.

Anti-Infective Agents↗
PubMed1996

Anticarcinoma activity of a novel drug, 3-ethyl-3'-methyl-thiatelluracarbocyanine iodide (Te), a tellurium-containing cyanine targeted at mitochondria.

Lipophilic cationic compounds such as rhodamine 123, AA1, and dequalinium chloride have been reported to constitute a new class of anticarcinoma agents based on their selective localization, accumulation, and retention within the mitochondria of certain carcinoma cells. After screening more than 1000 lipophilic cationic compounds in clonogenic assays, we found that a tellurium-containing cyanine, 3-ethyl-3'-methyl-thiatelluracarbocyanine iodide (Te), exhibits significant anticarcinoma activity. In vitro testing showed that Te was 64-fold more toxic to the carcinoma cell line CX-1 than to the normal epithelial cell line CV-1. In vivo testing showed that Te significantly prolonged the survival of mice implanted with tumors. For C57BL x DBA/2 F1 mice implanted with the mouse bladder carcinoma cell line MB49, the treated:control (T:C) ratio ranged from 250 to 268%. For Swiss nu/nu mice implanted with the human melanoma cell line LOX, the T:C ratio ranged from 176 to 270%. For Swiss nu/nu mice implanted with the human ovarian tumor cell line OVCA-III, the T:C ratio was 344%. These anticarcinoma activities warrant further investigation of Te as a potential anticarcinoma agent.

Animals↗
PubMed1995

Endogenous acetylcholine-induced Fos expression in magnocellular neurosecretory neurons in the supraoptic nucleus of the rat hypothalamus.

Induction of c-Fos expression in the supraoptic nucleus (SON) of the rat hypothalamus by endogenous acetylcholine was examined by microinfusion of neostigmine, a cholinesterase inhibitor, into the nucleus to locally accumulate the spontaneously released acetylcholine from the cholinergic terminals in the SON. Double staining of the neurosecretory neurons with antiserum to Fos, the protein product of c-Fos, and antiserum to vasopressin or oxytocin was performed. Fos-like immunoreactivity was manifested in both the vasopressin neurons and oxytocin neurons following the microinfusion of neostigmine. Microinfusion of nicotinic agonist, nicotine, to the SON also induced Fos expression, but mainly in the vasopressin neurons. Microinfusion of muscarinic agonist, carbachol, induced Fos expression as well, but mostly in the oxytocin neurons.

Acetylcholine↗
PubMed1995

Preparation of tau from the peripheral nerve: presence of insoluble low molecular weight tau with high phosphorylation.

Purely axonal tau protein of the peripheral nervous system (PNS) obtained from adult rat ventral roots was composed of both high (HMW) and low molecular weight (LMW) isoforms. While the PNS-specific HMW isoform (110 kDa) was soluble, 60-70% of the LMW isoforms with apparent molecular weights of 67 kDa, 62 kDa and 58 kDa was insoluble. When analyzed by two-dimensional electrophoresis, these axonal LMW isoforms corresponded to the most acidic species among the large number of isoforms found in brain microtubule-associated tau. Immunoreactivities towards phosphorylation-dependent antibody tau-1 and the two anti-phosphopeptide antibodies (PP1 and PP2) indicate that PNS axonal tau is highly phosphorylated at Ser190, Ser193, and Ser387, which are the sites shown to be phosphorylated in fetal brain tau and tau comprising the paired helical filaments of Alzheimer's disease.

Animals↗
PubMed1995

Generation of the glycyl radical of the anaerobic Escherichia coli ribonucleotide reductase requires a specific activating enzyme.

The anaerobic ribonucleotide reductase from Escherichia coli contains a glycyl radical as part of its polypeptide structure. The radical is generated by an enzyme system present in E. coli. The reductase is coded for by the nrdD gene located at 96 min. Immediately downstream, we now find an open reading frame with the potential to code for a 17.5-kDa protein with sequence homology to a protein required for the generation of the glycyl radical of pyruvate formate lyase. The protein corresponding to this open reading frame is required for the generation of the glycyl radical of the anaerobic reductase and binds tightly to the reductase. The "activase" contains iron, required for activity. The general requirements for generation of a glycyl radical are identical for the reductase and pyruvate formate lyase. For the reductase, the requirement of an iron-containing activase suggests the possibility that the iron-sulfur cluster of the enzyme is not involved in radical generation but may participate directly in the reduction of the ribonucleotide.

Amino Acid Sequence↗
PubMed1995

Endotoxin-resistant mice are protected from PAF-induced bowel injury and death. Role of TNF, complement activation, and endogenous PAF production.

C3H/HeJ (endotoxin-resistant) mice have been used widely in biological research. However, the mechanism of endotoxin (LPS) resistance is only partially understood. In this study, we first investigated the differences in response to PAF, a mediator of endotoxin shock, between normal and C3H/HeJ mice. We found that in control mice, PAF (2.5 micrograms/kg) caused shock, hemoconcentration, complement activation, intestinal hypoperfusion, and necrosis with 75% mortality, whereas all C3H/HeJ mice survived, without complement activation or intestinal injury, and manifesting only mild hypotension and hemoconcentration. PAF also caused elevated serum TNF-alpha in some control mice but not in C3H/HeJ mice. We also observed that PAF induces endogenous PAF production and intestinal phospholipase A2 activation in normal mice, whereas PAF production and phospholipase A2 are suppressed in C3H/HeJ mice. The low endogenous PAF production may account, at least in part, for the resistance to LPS and PAF of C3H/HeJ mice.

Animals↗