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Biomedical subjects

Z Mao

Publications and source records attributed to Z Mao.

At least 19 recordsLinked to original sources
PubMed2003

Thiazolidinediones, a class of anti-diabetic drugs, inhibit Id2 expression through a PPARgamma-independent pathway in human aortic smooth muscle cells.

Inhibitor of DNA binding (Id2) is a member of the helix-loop-helix family of transcription regulators that is known to play important roles in the proliferation and differentiation of many cell types. Overexpression of Id2 has been reported to result in significant enhancement of vascular smooth muscle cell growth via increased S phase entry. We hypothesized that downregulation of Id2 gene expression by thiazolidinediones (TZDs), a class of anti-diabetic drugs and peroxisome proliferator-activated receptor gamma (PPARgamma) activators, might contribute to the anti-atherosclerotic and anti-hypertensive effects of the PPARgamma. Here we document that TZDs, including troglitazone and ciglitazone, repress Id2 gene expression in a doses- and time-dependent manner. However, GW7845, a high-affinity and non-TZD PPARgamma activator, had no inhibitory effect on Id2 gene expression. In addition, PPARgamma antagonist GW9662 did not rescue TZD-induced Id2 repression. Taken together, our data suggest that TZDs repress Id2 expression through a PPARgamma-independent pathway.

Anilides↗
PubMed2002

The human tuftelin gene and the expression of tuftelin in mineralizing and nonmineralizing tissues.

Tuftelin has been suggested to play an important role during the development and mineralization of enamel, but its precise function is still unclear. This article reviews major milestones in the discovery, structural characterization, expression, localization, and conservation of tuftelin in different vertebrate species. It focuses on the structure of the human tuftelin gene, which has recently been deciphered [12]. It describes the exon-intron organization, sizes and structure, the promoter structure, and the newly discovered alternatively spliced human tooth-bud tuftelin mRNA transcripts. It also examines information on the structural motifs in the human-derived tuftelin protein and how they relate to tuftelin from other species. It reviews our recent results on the transcription of tuftelin mRNA and protein expression in several nonmineralizing soft tissues, using reverse-transcription polymerase chain reaction (RT-PCR) followed by DNA cloning and sequencing, indirect immunohistochemistry, immunohistochemistry combined with confocal microscopy, and in situ hybridization. These results and earlier Northern blot results show that tuftelin, in addition to being expressed in the developing and mineralizing tooth, is also expressed in several nonmineralizing soft tissues, suggesting that tuftelin has a universal function and/or a multifunctional role.

Alternative Splicing↗
PubMed2002

Effects of cigarette tax on cigarette consumption and the Chinese economy.

OBJECTIVES: To analyse a policy dilemma in China on public health versus the tobacco economy through additional cigarette tax. METHODS: Using published statistics from 1980 through 1997 to estimate the impact of tobacco production and consumption on government revenue and the entire economy. These estimates relied on the results of estimated price elasticities of the demand for cigarettes in China. RESULTS: Given the estimated price elasticities (-0.54), by introducing an additional 10% increase in cigarette tax per pack (from the current 40% to 50% tax rate), the central government tax revenue would twice exceed total losses in industry revenue, tobacco farmers' income, and local tax revenue. In addition, between 1.44 and 2.16 million lives would be saved by this tax increase. CONCLUSIONS: Additional taxation on cigarettes in China would be a desirable public policy for the Chinese government to consider.

China↗
PubMed2001

The human tuftelin gene: cloning and characterization.

Tuftelin has been suggested to play an important role during the development and mineralization of enamel. We isolated the full-length human tuftelin cDNA using reverse transcription-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (5' RACE and 3' RACE) methods. Sequence analysis of the tuftelin cDNA revealed an open reading frame of 1170 bp encoding a 390 amino acid protein with a molecular mass of 44.3 kDa and an isoelectric point of 5.7. The human tuftelin protein shares 89 and 88% amino acid sequence identity with the bovine and mouse tuftelin, respectively. It contains a coiled-coil region, recently reported to be involved with tuftelin self-assembly and with the interaction of tuftelin with TIP39 (a novel tuftelin interacting protein). Detailed DNA analysis of the cloned genomic DNA revealed that the human tuftelin gene contains 13 exons and is larger than 26 kb. Two alternatively spliced tuftelin mRNA transcripts have now been identified in the human tooth bud, one lacking exon 2, and the other lacking exon 2 and exon 3. Primer extension analysis, corroborated by RT-PCR and DNA sequencing, revealed multiple transcription initiation sites. The cloned 1.6 kb promoter region contained several GC boxes and several transcription factor binding sites such as those for activator protein 1 and stimulatory protein 1. Our blast search of the human and mouse expressed sequence tag data bases, as well as our RT-PCR and DNA sequencing results, and a previous study using Northern blot analysis revealed that tuftelin cDNA sequences are also expressed in normal and cancerous non-mineralizing soft tissues, suggesting that tuftelin has a universal function. We have now identified and characterized different alternatively spliced mouse tuftelin mRNAs in several non-mineralizing tissues. These results provide an important baseline for future understanding of the biological role of tuftelin.

5' Flanking Region↗
PubMed2001

Multivariate prognostic analysis of stage I(E) primary non-Hodgkin's lymphomas of the nasal cavity.

From January 1968 to December 1997, a total of 71 patients with stage I(E) (Ann Arbor staging system, 1971) primary non-Hodgkin's lymphomas of the nasal cavity received treatment in the Cancer Center of Sun Yat-Sen University of Medical Sciences. Thirty-seven lesions were limited to the nasal cavity (limited I(E)), whereas the other 34 were extended to the structure out of the nasal cavity (extended I(E)). Forty-four patients were treated with radiochemotherapy and 27 with radiotherapy alone. Kaplan-Meier methods were used in the survival analysis. Multivariate analysis was carried out using the Cox proportional hazard model. The 5- and 10-year survival rates were 71.85% and 59.67% for the patients with a complete response to irradiation, and both were 13.89% for the patients with residue lesions (p = 0.0004). The 5- and 10-year survival rates were 69.81% and 56.72% for limited I(E), and 40.65% and 35.57% for extended I(E) (p = 0.0047). The prognosis was better for those younger than 44 years (p = 0.0003). The 10-year survival rates for radiotherapy alone and combined radiochemotherapy are 52% and 75% for limited I(E) versus 37.58% and 45% for extended I(E) (p = 0.0644). B symptoms did not significantly affect clinical outcome (p = 0.729). Multivariate analysis showed that complete response of local lesion after radiotherapy, invasion of the primary tumor to adjacent structures, and patients' age were independent prognostic factors. Our study showed that radiotherapy is the main treatment method for the primary non-Hodgkin's lymphomas of the nasal cavity; the addition of chemotherapy may improve long-term survival. The local tumor response to radiotherapy, whether the extranasal structures were invaded, and patients' age were independent prognostic factors.

Adolescent↗
PubMed2001

Presence of antibody against the inducible Hsp71 in patients with acute heat-induced illness.

Antibodies against heat shock or stress proteins (Hsps) have been reported in a number of diseases in which they may be involved in the pathogenesis of the disease or may be of use for prognosis. Heat-induced diseases, such as heat cramps, heat exhaustion, or heat stroke, are frequent in hot working or living environments. There are still few investigations on the presence and possible significance of autoantibodies against Hsps in heat-induced illnesses. Using an immunoblotting technique with recombinant human Hsps, we analyzed the presence and titers of antibodies against Hsp60, Hsp71, and Hsp90alpha, and Hsp90beta in a group of 42 young male patients who presented with acute heat-induced illness during training. We also examined the presence of antibody against Hsp71 in a second group of 57 patients with acute heat-induced illness and measured the changes in titers of anti-Hsp71 antibodies in 9 patients hospitalized by emergency physicians. In the first group of young persons exercising in a hot environment, the occurrence of antibodies against Hsp71 and Hsp90alpha was significantly higher among individuals with symptoms of heat-induced illness (P < 0.05) than in the matched group of nonaffected exercising individuals. Moreover titers of antibody against Hsp71 were higher in individuals of the severe and mild heat-induced illness groups, the highest titer being found in the most severe cases. The results from the second group of 57 heat-affected patients exposed to extreme heat were similar. Again, patients with the more severe heat-induced symptoms showed a significantly higher incidence of antibodies to Hsp71 than controls and the titer of anti-Hsp71 was higher in the severely affected group. Finally, in a study of 9 patients, it was observed that the titer of anti-Hsp71 decreased during recovery from severe heat symptoms. These results suggest that measurement of antibodies to Hsps may be useful in assessing how individuals are responding to abnormal stress within their living and working environment and may be used as one biomarker to evaluate their susceptibility to heat-induced diseases.

Adolescent↗
PubMed2001

Fine mapping of canine XLPRA establishes homology of the human and canine RP3 intervals.

PURPOSE: Canine X-linked progressive retinal atrophy (XLPRA) is a hereditary, progressive retinal degeneration that has been mapped previously to the canine X chromosome in a region flanked by the dystrophin (DMD) and tissue inhibitor of metalloproteinase 1 (TIMP1) genes, and is tightly linked to the gene RPGR. The comparable region of the human X chromosome includes the disease locus for RP3, an X-linked form of retinitis pigmentosa, although the current canine disease interval is much larger. METHODS: To refine the map of the canine XLPRA disease interval, 11 X-linked markers were mapped, both meiotically, in two extensive canine pedigrees informative for XLPRA, and on a 3000-rad canine-hamster radiation hybrid (RH) panel. A 12th marker was mapped on the RH panel alone. RESULTS: The integrated map of this region of CFAX now covers approximately 47.3 centimorgans (cM) and 194 centirays (cR)(3000), and demonstrates strong conservation of synteny between humans and dogs. Genes defining the human RP3 zero-recombination interval (human homologue of mouse t complex [TCTE1L], sushi repeat-containing protein, X chromosome [SRPX], and retinitis pigmentosa guanosine triphosphatase [GTPase] regulator [RPGR]) are tightly linked to each other, to the XLPRA locus, and to the gene ornithine transcarbamylase (OTC) in dogs. CONCLUSIONS: Strong conservation of gene order was demonstrated in the short arm of the X chromosome between dogs and humans as was homology of the canine XLPRA and human RP3 intervals. These results create a valuable tool for investigating canine XLPRA and other X-linked eye diseases in dogs.

Animals↗
PubMed2001

[Surgical treatment of great vessel injuries of thoracic outlet].

OBJECTIVE: To summarize the experience in surgical treatment of great vessel injury of the thoracic outlet. METHODS: Thirty-two cases (24 men and 8 women aged 2-48 years) treated by surgery were collected during the period of 1970-1998. Sharp injury, blunt injury or decelerated injury was the causes. The vessels of injury included the common carotid artery, subclavian artery and accompanying veins. Emergency suture or repair of the artery with polyester patch was performed in 15 patients, aneurysmectomy in 6, resection of vessels with end-to-end anastomosis in 5, Gore-Tex vessel reconstruction in 2, and transplantation of the great saphenous vein in 3. RESULTS: Twenty-four patients (75%) were cared and 7 (21.8%) died. CONCLUSIONS: In the early period, patients with great vessel injury of the thoracic outlet died from acute bleeding, cerebral ischemia or combined multiple injuries, in the later period, however, false aneurysm develop. The operation is appropriate to the recondition of damaged cut, the effect of evolution in false aneurysm is approving. For large damaged cut or for bigger vessel injuries, the repair with polyester patch, Gore-Tex of blood vessel reconstruction or the transplantation of the great saphenous vein must be used.

Adolescent↗
PubMed2001

[Apoptosis induced by interstitial irradiation with 32P glass microspheres combination with hyperthermia in mouse solid tumor S180].

OBJECTIVE: The aim of this study was to observe the changes of tumor cell apoptosis after interstitial irradiation combination with the hyperthermia treatment. METHODS: Twenty mice with solid tumor S180 were divided into four groups, including a control group which was given normal saline, and three experimental groups which were respectively applied with a hyperthermia treatment (bath water), interstitial irradiation with 32P glass microspheres, and the combined treatment of hyperthermia and interstitial irradiation. The terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method was used to determine the final apoptotic cells. RESULTS: The mean values of apoptotic indexes of these four groups were respectively 0.39, 0.53, 0.59 and 0.91. The apoptotic indexes of these experimental groups were significantly higher than that of the control group (P < 0.05). The apoptotic index of the combined treatment group was significantly higher than those of the hyperthermia group and the interstitial irradiation group (P < 0.05). CONCLUSION: Both the interstitial irradiated with 32P glass microspheres and hyperthermia (bath water) can induce the apoptosis of mouse solid tumor S180. It seems that there is a synergistic induction of apoptosis between interstitial irradiation and hyperthermia.

Animals↗
PubMed2001

[Relationship between the expression of Bax and apoptosis induced by hyperthermia in BcaCD885 cells].

OBJECTIVE: This study aimed to investigate the role of Bax gene in apoptosis induced by hyperthermia in BcaCD885 cells. METHODS: After inducing apoptosis through hyperthermia, the expression of Bax protein and mRNA were examined with FCM antibody analysis and RT-PCR technique respectively. RESULTS: Up regulation of Bax protein was noted after hyperthermia. The correlation coefficient r between the apoptotic rate and the expression Bax protein was 0.9240. The expression of Bax mRNA was also raised after hyperthermia. CONCLUSION: Hyperthermia acting as an external signal may up-regulates expression of Bax gene and then induces apoptosis in BcaCD885 cells.

Apoptosis↗
PubMed2000

Polarized-neutron scattering study of the cooper-pair moment in Sr2RuO4.

We report a study of the magnetization density in the mixed state of the unconventional superconductor Sr2RuO4. On entering the superconducting state we find no change in the magnitude or distribution of the induced moment for a magnetic field of 1 T applied within the Ru O2 planes. Our results are consistent with a spin-triplet Cooper pairing with spins lying in the basal plane. This is in contrast with similar experiments performed on conventional and high- T(c) superconductors.

Journal Article↗
PubMed2000

A convenient synthesis and spectroscopic characterization of N, N'-Bis(2-propenyl)-2,7-diazapyrenium quaternary salts

N,N'-Bis(2-propenyl)-2,7-diazapyrenium salts are synthesized in good yield from the reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with allylamine, followed by LiAlH(4) reduction and subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The nature of the counteranion depends on the solvent system used for recrystallization of the crude product from the final DDQ-oxidation step. X-ray analysis shows that if recrystallization is carried out in boiling CH(3)OH/H(2)O (1:1, v/v), the counteranion in the resulting deep-red crystals is always the alkoxy anion of 2-cyano-5,6-dichloro-3-hydroxy-1,4-benzoquinone, whether the final DDQ oxidation ends with addition of HClO(4) or HCl; on the other hand, if recrystallization is carried out with anhydrous acetonitrile, the product is N,N'-bis(2-propenyl)-2,7-diazapyrenium diperchlorate or dichloride depending on whether the DDQ oxidation is followed by addition of concd HClO(4) or concd HCl, respectively. Importantly, if the DDQ oxidation is quenched with HBr, Br(-) is oxidized to Br(2) by unreacted DDQ, and the resulting product is N, N'-bis(2,3-dibromopropyl)-2,7-diazapyrenium dibromide. Comparative absorption and time-resolved emission studies provide evidence for possible dimerization of N,N'-bis(2-propenyl)-2,7-diazapyrenium diperchlorate in CH(3)CN.

Journal Article↗
PubMed2000

Cloning and functional characterization of the 5'-flanking region of human methionine adenosyltransferase 1A gene.

Methionine adenosyltransferase (MAT) is an essential cellular enzyme which catalyses the formation of S-adenosylmethionine, the principal methyl donor and precursor for polyamines. In mammals, two different genes, MAT1A and MAT2A, encode for liver-specific and non-liver-specific MAT respectively. We previously described a switch in the MAT expression from MAT1A to MAT2A in human liver cancer, which offered the cancerous cell a growth advantage. Loss of MAT1A expression was due to lack of gene transcription. To study regulation of the MAT1A gene, we have cloned and characterized a 1.9 kb 5'-flanking region of the human MAT1A gene. One transcriptional start site, located 25 nt downstream from a consensus TATA box, was identified by primer extension and RNase protection assays. The promoter contains several consensus binding sites for CAAT enhancer binding protein (C/EBP) and hepatocyte-enriched nuclear factor (HNF), transcriptional factors important in liver-specific gene expression. The human MAT1A promoter was able to efficiently drive luciferase expression in Chang cells, a human liver cell line, but not in HeLa cells. Sequential deletion analysis of the promoter revealed two DNA regions upstream of the translational start site, -705 to -839 bp and -1111 to -1483 bp, which are involved in positive and negative gene regulation, respectively. Specific protein binding to these regions was confirmed by electrophoretic-mobility-shift and DNase I footprinting assays. Similar to the situation with the rat MAT1A, glucocorticoid treatment also increased human MAT1A expression and promoter activity in a dose- and time-dependent manner.

5' Untranslated Regions↗
PubMed2000

Expression of p53 and p21 protein in transitional mucosa adjacent to rectal carcinoma and its clinical implication.

To study the biopathological characteristics of the transitional mucosa adjacent to rectal carcinoma, 34 cases were subjected to mucin histochemical and immunohistochemical study to observe the expression of p53 and p21 protein in distal mucosa adjacent to rectal carcinoma and its relationship to the mucin change. The expression of p53 protein was found in 29.4% (10/34) of distal transitional mucosa in the cytoplasm of goblet cells, and its positive staining was within 4 cm from carcinoma margin. All p53 positive mucosa was transitional mucosa. Overexpression of p21 protein was found in 26.5% (9/34) of distal transitional mucosa in cytoplasm of crypt cells, and its positive staining was within 2 cm from carcinoma margin. There was no relationship between the expression of p53 and p21 protein in carcinoma and that in transitional mucosa (P > 0.05). These findings indicated that there was aberrant alteration of p53 and p21 genes in transitional mucosa adjacent to colorectal carcinoma, which provided further evidence that transitional mucosa was an unstable pre-cancerous change. The aberrant mucin change and genetic alteration in distal mucosa of rectal cancer is within 4 cm.

Adenocarcinoma↗
PubMed2000

Nanosecond electron microscopes

Combining electron optics, fast electronics and pulsed lasers, a transmission and a photoelectron emission microscope were built, which visualize events in thin films and on surfaces with a time resolution of several nanoseconds. The high-speed electron microscopy is capable to track fast laser-induced processes in metals below the ablation threshold, which are difficult to detect by other imaging techniques. The material response to nano- and femtosecond laser pulses was found to be very different. It was dominated by thermo/chemocapillary flow and chemical reactions in the case of nanosecond pulses, and by mechanical deformations and non-thermal electron emission after a femtosecond pulse.

Journal Article↗
PubMed2000

[A study on relationship between plasma heat stress protein 70 and cytokine in patients with heat apoplexy].

OBJECTIVE: To study the change of levels of plasma heat stress protein 70 (HSP70) and cytokine and their interrelationship in pathogenicity of heat apoplexy. METHODS: Plasma HSP70 was determined with Western blot, and plasma interleukin-2 (IL-2), soluble interleukin-2 receptor (sIL-2R) and interleukin-6 (IL-6) were determined with enzyme-linked immunosorbent assay (ELISA). RESULTS: Plasma level of HSP70 was 4 211.2 +/- 1,286.2 (integral optical density) in average in the patients of heat apoplexy group, 4,137.8 +/- 1, 207.5 in those of severe heat apoplexy group, and 6,043.5 +/- 1,354.8 in control group, with very significant difference (P < 0.01). Plasma IL-2 level was (64.3 +/- 32.3) pg/ml and (200.0 +/- 50.0) pg/ml and sIL-2R (54.9 +/- 33.3) U/ml and (167.5 +/- 89.0) U/ml in the patients with heat apoplexy and in controls, respectively, with very significant difference. But, there was no significant difference in IL-6 between varied groups. CONCLUSIONS: The above-mentioned results suggest that establishment of heat acclimatization correlates to the interaction of network of neuroendocrine-cytokine-HSP, in which decrease in plasma IL-2 was one of the important factors causing reduction of HSP70 expression. Balance of network regulation was broken by pathological factors, finally resulting in heat apoplexy.

Adolescent↗
PubMed2000

[The expression of connexin 43 and desmin in viral myocarditis].

OBJECTIVE: To study the cytobiological basis of constriction dysfunction and arrhythmia in cardiac muscle cells with viral myocarditis. METHODS: The expression of connexin 43 and desmin in cardiac muscle cells of mice with experimental viral myocarditis was determined by immunohistochemistry. RESULTS: In normal mice, connexin 43 and desmin are located in the intercalated disks of cardiac muscle, and the latter also revealed a positive immunoreactivity in the cross striations of sarcomeres. In viral myocarditis, the expression of both became much weakened, can even become negative. CONCLUSION: In myocarditis, expression of connexin 43 and desmin in the involved cardiac muscle cells was inhibited, resulting in dysfunction of gap junctional communication and arrhythmia.

Animals↗