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Biomedical subjects

X Zhou

Publications and source records attributed to X Zhou.

At least 613 records · Page 34Linked to original sources
PubMed1996

Alterations of transforming growth factor-beta 1 receptor type II occur in ulcerative colitis-associated carcinomas, sporadic colorectal neoplasms, and esophageal carcinomas, but not in gastric neoplasms.

BACKGROUND & AIMS: Gastric cancers, sporadic colorectal cancers, and ulcerative colitis (UC)-associated colorectal carcinomas and dysplasias manifest microsatellite instability (MI); however, esophageal carcinomas rarely exhibit MI. Recently, a transforming growth factor-beta 1 type II receptor (TGF-beta 1RII) mutation in a coding microsatellite was described in primary colorectal carcinomas demonstrating MI. No previous studies of TGF-beta 1RII have addressed mechanisms of inactivation other than MI in human tumors; furthermore, MI-negative tumors have not been examined for TGF-beta 1RII mutation. We evaluated 138 primary human neoplasms for mutation in the poly-A microsatellite tract of TGF-beta 1RII. Additionally, a group of esophageal tumors was evaluated for the expression of TGF-beta 1RII messenger RNA (mRNA). METHODS: First, we determined whether MI was present at other chromosomal loci in these lesions. The poly-deoxyadenine (poly-A) microsatellite tract within the TGF-beta 1RII coding region was then PCR-amplified. In a group of MI-negative esophageal tumors, RT-PCR was performed to determine the expression of TGF-beta 1RII mRNA. RESULTS: Among 17 MI+ UC specimens, 3 (18%) demonstrated TGF-beta 1RII poly-A tract mutation (2 cancers and 1 dysplasia), while 2 (4%) of 44 MI-negative UC specimens (1 dysplasia and 1 tumor), and 13 (81%) of 16 MI+ sporadic colorectal cancers, contained TGF-beta 1RII poly-A mutation. No gastric or esophageal tumors contained TGF-beta 1RII mutation. Among 21 MI-negative esophageal carcinomas. 6 cases (28.5%) had TGF-beta 1RII transcripts that were low or undetectable by RT-PCR. CONCLUSIONS: Mutation within the poly-A microsatellite tract of TGF-beta 1RII occurs early in a subset of UC-neoplasms and commonly in sporadic colorectal cancers, but may be rare in MI+ gastric tumors. Diminished expression of TGF-beta 1RII mRNA in esophageal tumors suggests that mechanisms of inactivation in this gene other than MI play a role in esophageal carcinogenesis.

Colitis, Ulcerative↗
PubMed1996

Presence of free radicals in pigment gallstone in vivo.

OBJECTIVE: To clarify whether free radical, which may play a role in pigment gallstone formation, is present in pigment gallstones in vivo. MATERIALS AND METHODS: Free radical signal of gallstones from 18 patients was detected by electron paramagnetic resonance spectroscopy at 77K under anaerobic condition and in air (control). As soon as the anaerobic determination was finished, the fresh anaerobic sample was exposed to air and stored in a freezer at -20 degrees C. RESULTS: Free radical signal (g = 2.0038) was detected in fresh anaerobic samples containing more than 2% bilirubin compound, and the signal intensity correlated linearly with the content of calcium bilirubinate (r = +0.95, P < 0.0005). During the storage at -20 degrees C and exposure to air, the signal intensity of each anaerobic sample and its control increased gradually, eventually reaching the same stable level. Fe(III) signal intensity was enhanced synchronously and related linearly with free radical signal (r = +0.99, P < 0.0005). CONCLUSIONS: Free radical exists originally in pigment gallstones in vivo, and it may play an important role in pigment gallstone formation. The free radical signal carried by gallstones may be strengthened by the action of oxygen in air on bilirubin. The transition metal ions probably take part in the formation of bilirubin free radical.

Bilirubin↗
PubMed1996

[Induced-expression of MHC-DR molecules on mice islet cells].

The correlation of induced-expression of MHC-DR molecules with insulin release in cultured mice islet cells has been studied. The results showed that, (1) No detectable induced-expression of MHC-DR molecules by TNF-alpha alone at the concentration of 50-100 U/ml has been assayed, but the induced-expression of MHC-DR molecules has been identified in a few islet cells (8.5 +/- 2.9%) with IFN-r alone at concentration of 50-100 U/ml. (2) The induced-expression of MHC-DR molecules has been detected in as high as 80% of cultured islet cells with TNF-alpha and IFN-r combined at different concentrations. (3) Insulin released from cultured islet cells was enhanced by IFN-r and TNF-alpha either alone or combined at different concentrations. These results suggest that the induced-expression of MHC-DR molecules themselves does not damage the function for insulin release in cultured islet cells.

Animals↗
PubMed1996

Alterations of level of total genomic DNA methylation and pattern of c-myc, c-Ha-ras oncogene methylation in human gastric carcinogenesis.

OBJECTIVE: To investigate the status of DNA methylation in gastric carcinogenesis. METHODS: We analysed methylation pattern of c-myc, c-Ha-ras oncogenes by southern blot hybridization. DNA from cancerous, paracancerous and non-cancerous area of surgically resected samples in 21 cases of advanced gastric cancer were digested with MspI/HpaII and hybridized with the two genomic 32P labelled probes. In addition, the level of total genomic DNA methylation was measured by incubating DNA with 3H-S-Adenosylmethionine (3H-SAM) in the presence of a methylase which methylates all the cytosine residues that are in the double CpG (cytosine-guanine). RESULTS: The results indicated that both c-myc and c-Ha-ras oncogene fragments containing CCGG sequence were hypomethylated in DNA samples from cancerous (10/21 and 5/10) and paracancerous (13/21 and 4/10) areas. Moreover, the level of total genomic DNA methylation in cancerous tissue was significantly lower than that in non-cancerous and paracancerous mucosa tissues (P < 0.05). The results from two methods are incompletely alike. CONCLUSION: These results supported a strong correlation between DNA hypomethylation and gastric carcinogenesis, particularly methylated pattern of c-myc and c-Ha-ras oncogenes fragments containing CCGG sequence was abnormal in gastric mucosa tissue from gastric cancerous and paracancerous areas.

Adult↗
PubMed1996

[Changing prognosis of primary liver cancer: some aspects to improve long-term survival].

The authors reported the changing prognosis of primary liver cancer (PLC) during the last three decades and the factors improving long-term results. Two thousand three hundred and eighty eight pathologically proven PLC cases were analyzed. Of them, 569 cases (23.8%) were small-sized PLC (< or = 5 cm in diameter). Hepatic resection was performed in 1,650 cases (69.1%) and local resection was done in 1,202 of the 1,650 (72.8%). Follow-up study was carried out every 2-3 months during the first 2 years after resection and every 6 months thereafter. For some unresectable huge PLC, cytoreduction and subsequent resection were performed. Five-year survival rate was 4.8% in 1958-1970 (n = 187), 11.2% in 1971-1982 (n = 582), and 45.7% in 1983-1994 (n = 1,628), respectively. Re-resection of subclinical recurrence was performed in 147 cases. Cytoreduction and subsequent resection were carried out in 71 cases. It is concluded that markedly changing prognosis of PLC was observed; factors improving long-term survival included (1) early detection and radical resection, (2) local resection instead of lobectomy, (3) re-resection for subclinical recurrence, and (4) cytoreduction and subsequent resection for otherwise unresectable PLC.

Adolescent↗
PubMed1996

Increased expression of PDGF and c-myc genes in lungs and pulmonary arteries of pulmonary hypertensive rats induced by hypoxia.

The role of growth factors and proto-oncogene in pulmonary vascular structural remodelling is not well known. The present study examined gene expression of platelet-derived growth factor (PDGF)-A and -B chain and proto-oncogene, c-myc, in lung tissue and pulmonary artery of rats exposed to hypoxia and compared to those levels of gene expression in normal rats. Normal lungs and pulmonary artery expressed PDGF-A chain transcript of 1.7 kb and PDGF-B chain transcript of 3.5 Kb. The c-myc transcript of 2.2 kb was expressed as well. After hypoxic exposure for 7 and 14 days mRNA levels of PDGF-B chain and c-myc were elevated significantly compared with those of control rats. PDGF-A chain mRNA increased after hypoxia for 7 days, and then declined. These results suggest that activation of autocrine and/or paracrine is important in proliferation mechanism of pulmonary artery smooth muscle cells in hypoxic pulmonary hypertensive rats.

Animals↗
PubMed1996

[Anatomic observation of the dorsal metacarpal arteries].

Anastomosis between the first to the fourth dorsal metacarpal arteries was observed in 43 hands of adult corpses. It was found that 86% of the first dorsal metacarpal artery arises from the radial artery, 14% is replaced by the main artery of thumb or superficial branches of the radial arteries; eighty-six percent of the second dorsal metacarpal artery originates from the dorsal carpal artery. Sixty-seven percent of the third and the fourth dorsal metacarpal arteries is formed by anastomosis of the dorsal carpal artery and its deep palmar arch. The first to the fourth dorsal metacarpal arteries have 4 to 8 cutaneous branches and proximal and distal anastomoses. It is concluded that the dorsal metacarpal arteries are characterized with multiple sources and abundant anastomoses around the metacarpophalangeal joints, which can be used with advantage in the repair of soft tissue defects of the area.

Adult↗
PubMed1996

[Monocellular quantitative study on the adhesive ability of eosinophils in the course of eosinophils activation].

OBJECTIVE: To observe the dynamic changes of eosinophils (EOS) adhesive ability in the course of eosinophils activation. METHODS: The adhesive ability EOS to vascular endothelial cell (EC) was measured by the use of a microminpulation technique. RESULTS: The critical separation stress (Sc) between rest EOS and EC was 0.61 +/- 0.07kPa. Treatment of EOS with platelet activaty factor (PAF) caused a significant increase in Sc. The Sc was 4.1 +/- 0.6kPa within 30 minutes of EOS exposure to PAF, and had no tendency to increase continuously by exposure time prolonged. CONCLUSIONS: The increase of EOS adhesive ability belongs to a kind of rapid response while EOS is activated. The increase could be an important basis of EOS adhesion to EC and EOS entry into bronchial mucosa.

Cell Adhesion↗
PubMed1996

[Observations of cellular differentiation behaviour in adenoid cystic carcinoma of human salivary gland in vitro].

The celluar differentiation behaviour of adenoid cystic carcinoma (ACC) of salivary gland was investigated in vitro with immunohistochemistry. The results showed that the cells of ACC-2 and ACC-3 cell lines can express some marker proteins in vitro including S-100 protein, actin, myosin which is characterized as a feature of myoepithelial cells. When differentiation inducer, dB-cAMP, was added to the monolayer cells cultured in dishes, the marker protein expression increased and the CEA changed to positive. The cellular differetiation behaviour of ACC cells is related to the proliferate speed of cells. Some cells manifested finger ring-like when the culture condition was changed, it means that these cells have the secretory function. If the ACC cells were suspended singly in collagen gels which performed as an extracellular matrix they grew and formed the tubule-like structure. The results will help us to understand the histogenesis of ACC, the source of myoepithelial cells in ACC and the variety of histological structures of ACC.

Actins↗
PubMed1996

[Experimental studies on effects of excessive iodine intake on morphology and function of kidney in mice].

To understand that if excessive iodine can cause damage to tissues other than thyroid gland, mice were fed with iodine-excess water and iodine-excess goiter was caused in them. Hisitomorphology and function of the kidney, in addition to the thyroid gland, in goiter mice were observed. Results showed that two hundred days after being fed with 3,000 micrograms iodine per liter water, in addition to causing iodine-excess goiter characterized with proliferation of large amount of colloid in thyroid follicles, morphology and function of the kidneys in mice were significantly damaged, with prominent pathomorphological changes of crescent formation and metabolic inhibition in microsome membrane Na(+)-K(+)-ATPase activities in their kidneys. Na(+)-K(+)-ATPase activities were 21.95 +/- 7.50 mumolPi/mg Pr.hr in low iodine group, and 17.64 +/- 8.63 mumolPi/mg Pr.hr in excessive iodine group, with significant difference. It suggests that excessive iodine can cause damage not only to thyroid, but to the whole body.

Animals↗
PubMed1996

[Prognostic factors of primary liver cancer].

To investigate the prognostic factors of primary liver cancer (PLC) and improve the long-term results, 1,248 cases of PLC were analysed. Univariate analysis demonstrated that discovery approach, staging of PLC, original gamma-GPT, resection, radical resection, original AFP, tumor size, tumor number, and tumor capsule have very significant effects on prognosis of PLC (all P < 0.001); cirrhosis, HBsAg, local resection, and tumor embolus in portal vein were also significant difference (all P < 0.05); age, sex, original AFP, hepatitis, and differentiation of PLC cells were no significant difference (all P > 0.05). Multivariate analysis demonstrated that original gamma-GPT, radical resection, tumor size, and tumor number were the most significant prognostic factors (all P < 0.001). Some aspects improving long-term survival were discussed.

Adolescent↗
PubMed1996

[Long-term results of multimodality treatment in patients with primary liver cancer].

This paper report the long-term results of multimodality treatment in 2388 patients with pathologically proven primary liver cancer (PLC) over the last three decades. The 5-and 10-year survival after resection of PLC was 39.3% and 29.2% respectively for the whole series (n = 1650), and 61.9% and 45.4% respectively for patients with small PLC (< or = 5 cm, n = 569). The 5-year survival after cryosurgery was 37.9% for the whole series (n = 191), and 53.1% for patients with small PLC (n = 56). The 5-year survival of 71 patients receiving sequential resection after cytoreduction therapy was 66.0%. The 5-year survival after re-resection for recurrence tumor (n = 147) was 34.5%. 214 patients survived more than 5 years; of these 113 patients (52.8%) were small PLC, and 57 patients survived more than 10 rears. It is concluded that early detection and resection of small PLC is the leading approach to get long-term survivors, cytoreduction and sequential resection might be an important approach to improving the prognosis of patients with unresectable PLC, re-resection for subclinical recurrance and metastasis after an initial curative resection was also important to prolong survival further.

Adolescent↗
PubMed1995

Distribution of growth-associated class I alpha-tubulin and class II beta-tubulin mRNAs in adult rat brain.

A comprehensive survey of class I alpha-tubulin (alpha 1) and class II beta-tubulin (beta II) mRNAs was performed using in situ hybridization in order to determine the extent of continued expression of these immature tubulin isotype mRNAs in the adult rat brain. Qualitatively similar distributions of the two isotype mRNAs were observed, with marked variations in hybridization intensity of both probes apparent across different brain regions. Neurons in a wide variety of structures throughout the brain exhibited intense hybridization signals. While the presence of large numbers of neurons with a moderate hybridization intensity could account for the relatively high level of total binding in some regions such as the cerebellar and dentate granule layers, in most cases higher regional mRNA levels reflected greater hybridization intensity per neuron. Little variability in hybridization intensity was typically seen between individual cells within specific nuclei throughout the brain. The presence of occasional intensely labeled neurons scattered throughout the basal ganglia provided the most striking exception to this pattern. While no qualitative differences between the distributions of alpha 1-tubulin and beta II-tubulin mRNAs were observed, consistent differences in the relative intensity of hybridization for alpha 1-tubulin versus beta II-tubulin mRNA were apparent in a few brain regions. Expression by glia did not appear to contribute significantly to detectable levels of either alpha 1-tubulin or beta II-tubulin mRNA. These findings suggest that continued expression of growth-associated tubulin isotype mRNAs may have functional significance in specific neuronal populations of the adult brain. Partial overlap between the distributions of alpha 1- and beta II-tubulin mRNAs and that of GAP-43 mRNA is discussed, as are potential roles for growth-associated tubulin gene expression in supporting cytoskeletal turnover, reactive axonal growth, and dendritic remodeling in the adult brain.

Animals↗
PubMed1995

Coordinated upregulation of alpha 1- and beta II-tubulin mRNAs during collateral axonal sprouting of central peptidergic neurons.

An in situ hybridization study was performed to determine the relationship between levels of mRNAs for the axonal growth-associated alpha 1-tubulin and beta II-tubulin isotypes and the process of collateral axonal sprouting by identified central nervous system (CNS) neurons. A unilateral hypothalamic knife-cut was used to hemisect the hypothalamoneurohypophysial tract, which results in a robust collateral sprouting response by the uninjured neurons of the contralateral supraoptic nucleus (SON) (Watt and Paden: Exp Neurol 111:9-24, 1991). At 10 and 30-35 days after the lesion, cryosections of the SON were obtained and hybridized with 35S-labeled cDNA probes specific to alpha 1- and beta II-tubulin mRNAs. Quantitative evaluation of the resulting autoradiographs revealed that alpha 1-tubulin mRNA levels were significantly increased by 10 days in SON neurons that were undergoing collateral sprouting compared to controls and that this increase was sustained at 30-35 days post-lesion. Less marked increases in hybridization intensity of the beta II-tubulin probe were also apparent in sprouting neurons at both 10 and 30-35 days after the lesion, but were statistically significant only at 10 days. The measured increases in intensity of hybridization of alpha 1- and beta II-tubulin probes are likely to be conservative estimates of the underlying increase in alpha 1- and beta II-tubulin mRNA levels because sprouting SON neurons undergo significant hypertrophy. High levels of both alpha 1- and beta II-tubulin mRNAs were also seen in surviving axotomized SON neurons ipsilateral to the hypothalamic lesion. We conclude that the pattern of regulation of alpha 1- and beta II-tubulin mRNAs in CNS neurons which are capable of supporting new axonal growth includes three elements: maintenance of significant basal alpha 1- and beta II-tubulin mRNA pools in mature neurons, rapid increases in the pool size of the mRNAs following stimulation of collateral sprouting, and sustained elevation of mRNA levels during the period of axonal sprouting.

Animals↗
PubMed1995

Effect of 1-O-octadecyl-2-O-methyl-glycerophosphocholine on phosphatidylcholine and phosphatidylethanolamine synthesis in MCF-7 and A549 cells and its relationship to inhibition of cell proliferation.

The role of perturbation of lipid synthesis in the inhibition of cell proliferation by OctMeGroPCho was investigated with sensitive (MCF-7) and resilient (A549) cell lines. It inhibited de novo synthesis of phosphatidylcholine in both cells but increased triacylglycerol synthesis in A549 cells and phosphatidylethanolamine, phosphatidic acid and diacylglycerol synthesis in MCF-7 cells. The inhibition of synthesis of CDP-choline metabolites in MCF-7 cells and phosphatidylcholine biosynthetic enzyme activities in vitro by OctMeGroPCho suggests that direct inhibition of phosphocholine cytidylyltransferase may contribute to the observed inhibition of phosphatidylcholine synthesis. The activation of phosphoethanolamine cytidylyltransferase and ethanolamine phosphotransferase activities by OctMeGroPCho in vitro and increased production of CDP-ethanolamine suggest that stimulation of the above enzymes by OctMeGroPCho in the cells is responsible for the increased phosphatidylethanolamine synthesis. The apparent effect of OctMeGroPCho on intracellular lipid-metabolising enzymes is a strong indication that it may be widely distributed intracellularly and not just confined to the plasma membrane. The decrease in phosphatidylcholine synthesis by OctMeGroPCho in MCF-7 cells was prevented by co-incubation with oleic acid without any effect on the inhibition of cell growth. Although OctMeGroPCho resulted in similar decreases in phosphatidylcholine content in both cells, this did not affect the proliferation of A549 cells. The above results indicate that, although OctMeGroPCho has profound effects on lipid metabolism, these changes are not responsible for the inhibition of proliferation observed in MCF-7 cells.

Antineoplastic Agents↗
PubMed1995

Mutation responsible for the mouse pygmy phenotype in the developmentally regulated factor HMGI-C.

Growth is one of the fundamental aspects in the development of an organism. Classical genetic studies have isolated four viable, spontaneous mouse mutants disrupted in growth, leading to dwarfism. Pygmy is unique among these mutants because its phenotype cannot be explained by aberrations in the growth hormone-insulin-like growth factor endocrine pathway. Here we show that the pygmy phenotype arises from the inactivation of Hmgi-c (ref. 6), a member of the Hmgi family which function as architectural factors in the nuclear scaffold and are critical in the assembly of stereospecific transcriptional complexes. Hmgi-c and another Hmgi family member, Hmgi(gamma) (ref. 10), were found to be expressed predominantly during embryogenesis. The HMGI proteins are known to be regulated by cell cycle-dependent phosphorylation which alters their DNA binding affinity. These results demonstrate the important role of HMGI proteins in mammalian growth and development.

Alleles↗