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Biomedical subjects

Min Zhao

Publications and source records attributed to Min Zhao.

At least 73 records · Page 4Linked to original sources
PubMed2005

[The effect on apoptosis in anterior pituitary induced by cadmium chloride and its relations with caspase-9 pathway].

OBJECTIVE: To study the effects of cadmium chloride in anterior pituitary and the relation between apoptosis and expression of procaspase-9 mRNA. METHODS: In vivo studies:40 SD male rats were randomly distributed into four groups which were administered with CdCl2 at different doses by gavage for 6 weeks; IN VITRO STUDIES: the rats' anterior pituitary cells were primarily cultured for 120 hours, then treated with CdCl2 at the dose of 0, 1.56, 3.12, 6.25, 12.50, 25.00, 50.00, 100.00 micromol/L for 6 hours; The indices included: expression of procaspase-9 mRNA, detection of apoptosis with TUNEL assay. RESULTS: The results showed the excretion of ACTH, LH seemed to be decreased dramatically and the apoptosis inclined to enhance remarkably, and further more, the expression of procaspase-9 mRNA appeared to be increased significantly as compared with those of the control. It was show that a dose-effect relationship between the CdCl2 dosing and indices above with the regression analysis and a linear correlation between the mean gray value of apoptosis cell and the relative gray value of procaspase-9 mRNA positive cell. The results indicated that damnification, for example, apoptosis could be caused by certain dose of CdCl2 in anterior pituitary cells with dose dependent manner. Caspase-9 might play a role in the occurrence of apoptosis. CONCLUSION: It was suggested that cadmium could induce apoptosis of anterior pituitary both in vivo and in vitro in the manner of dose-dependent, and caspase-9 might play a role during above processes.

Animals↗
PubMed2005

[A comparison of the velopharyngeal closure after palatoplasty between with or without velopharyngeal muscular reconstruction].

OBJECTIVE: To evaluate the effect of palatoplasty with or without velopharyngeal muscular reconstruction on the velopharyngeal closure under the lateral radiography. METHODS: The lateral radiographs and cephalometric analysis were taken in sixty-two patients with cleft palate and velopharyngeal insufficiency, 32 repaired with velopharyngeal muscular reconstruction and 30 with modified von Langenbeck's procedure (non-reconstructive group). RESULTS: In patients with velopharyngeal muscular reconstruction, the velopharyngeal competence, the reductive rate of nasopharynx, the distance reduction in lower part of the mobile nasopharynx during phonation and the distance in middle part of mobile nasopharyngo in rest were superior to that without velopharyngeal muscular reconstruction, and there were variform PPW eminence-soft palate contact in velopharyngeal closure. The patients with complete or good velopharyngeal closure had a definite reduction in nasopharynx, compared to the patients with velopharyngeal insufficiency in the non-reconstructive group. CONCLUSIONS: The functional area for velopharyngeal closure after palatoplasty might be located in the middle part of mobile nasopharynx. The velopharyngeal muscular reconstruction in palatoplasty could reduce the size of nasopharynx and improve the coordination movement of velopharyngeal closure.

Adolescent↗
PubMed2005

[Immunohistochemical evidence for HIV-1 infection in the liver of HIV-infected patients].

OBJECTIVE: To detect p24 antigen of human immunodeficiency virus (HIV)-1 in the liver biopsy specimens of patients with HIV infection. METHODS: Liver biopsy samples from 14 patients with HIV/AIDS (11 man, 3 women; age range 27-52 years; infection time range 8-13 years) were examined by immunohistochemistry prospectively. RESULTS: Intracellular expression of HIV-1 p24 antigen was detected in Kupffer cells, endothelial cells and hepatocytes. There were more HIV-positive liver cells in the patients with severer liver damage than those with milder liver damage (t=2.5189, P=0.0270). CONCLUSION: These findings indicate that HIV-1 could replicate in the liver of HIV-infected patients and might be related to the liver cells apoptosis.

Adult↗
PubMed2005

[Repair of defect on finger skin with reverse fascial pedicle island flap of dorsal branch of digital artery].

OBJECTIVE: To introduce the surgical procedure and indication of the reverse fascial pedicle island flap of the digital artery dorsal branches in repairing finger skin defect. METHODS: By use of the dorsal branches of the digital artery as the pedicel, the reverse island flap was designed. The skin defects of the proximal interphalangeal joint and beyond in 35 cases (42 fingers) were repaired and the joint or extensor tendon was reconstructed simultaneously. Donor site was primarily closed or a skin graft was used. The flap size ranged from 1.0 cm x 2.5 cm to 1.5 cm x 3.5 cm. RESULTS: Thirty-five patients were followed up 3 months to 1 year, all the flaps survived. The two-point discrimination was between 6 mm and 10 mm. The function of interphalangeal joint was satisfactory. CONCLUSION: These flaps have the advantages of an extended skin paddle and a versatile pivot point on the phalanx, and they allow coverage of wide and distal defects.

Adult↗
PubMed2005

Expression and significance of Survivin mRNA in lung cancer tissue microarray detected by FISH.

OBJECTIVE: To investigate the expression of Survivin mRNA in lung cancer tissue microarray (TMA) by fluorescence in situ hybridization (FISH) method, and determine the role and significance of it in lung cancer genesis and progress. METHODS: The expression of Survivin mRNA was detected by FISH method and TMA technology. Fifty-four cases of lung cancer and 10 cases of normal lung tissue were examined. RESULTS: Survivin mRNA was expressed in 66.7% (36/54) of lung cancer; the positive ratio of lung cancer was significantly higher than that of normal lung tissue (0/10; chi2 = 15.238, P < 0.05). The positive ratio of Survivin mRNA was significantly higher in poor differentiated cancer (20/24, 83.3%) than moderate and well differentiated cancer (16/30, 53.3%; chi2 = 5.40, P < 0.05). The positive ratio of Survivin mRNA was significantly higher in group with lymph node metastasis (27/32, 84.4%) than without lymph node metastasis (9/22, 40.9%; chi2 = 11.084, P < 0.05). The positive ratio of Survivin mRNA was significantly higher in stage III-IV(12/13, 92.3%) than stage I - II (24/41, 58.5%; chi2 = 5.066, P < 0.05). CONCLUSION: Survivin mRNA highly expresses in lung cancer, which is related to the progress and malignant behavior. Survivin may play a promoting role in lung cancer genesis and progress and provide a basis for estimating prognosis and treatment.

Adenocarcinoma↗
PubMed2005

[Inhibition effect of methylene blue on the acids production of Streptococcus mutans].

OBJECTIVE: To study the effect of methylene blue on the growth and acid production of Streptococcus mutans, and the effect of methylene blue on acid production metabolism in plaque glycolysis model (i-PGM) in vitro, and investigate the practicability of methylene blue as a new kind of dental caries prevention agent. METHODS: Nephelometer method was used to measure OD value of Streptococcus mutans culture fluid in the different incubation conditions. The kinds and quantities of acid produced by Streptococcus mutans in the different incubation conditions were measured with gas chromatography. pH values of glycolysis buffer media of i-PGM in the different treatment conditions were measured by ORION electrode. RESULTS: (1) The OD value of Streptococcus mutans treated by methylene blue was lower than that by normal saline, and there was significant statistical difference between them. (2) The kinds of acid in three different culture fluid were same, but the total quantities of acid were significantly different among three different culture fluid, in which the total quantities of acid of culture fluids treated by glucose was the greatest, and treated by methylene blue was the lest. (3) The pH value of i-PGM treated by methylene blue was significantly different compared with negative control group, but was not significantly different compared with positive control group. CONCLUSION: Methylene blue can inhibit the growth and acid production metabolism of Streptococcus matans and acid production metabolism of i-PGM.

Dental Caries↗
PubMed2004

Lithium treatment inhibits renal GSK-3 activity and promotes cyclooxygenase 2-dependent polyuria.

The use of LiCl in clinical psychiatry is routinely complicated by overt nephrogenic diabetes insipidus (NDI), the mechanism of which is incompletely understood. In vitro studies indicate that lithium can induce renal medullary interstitial cell cyclooxygenase 2 (COX2) protein expression via inhibition of glycogen synthase kinase-3beta (GSK-3beta). Both COX1 and COX2 are expressed in the kidney. Renal prostaglandins have been suggested to play an important role in lithium-induced polyuria. The present studies examined whether induction of the COX2 isoform contributes to LiCl-induced polyuria. Four days after initiation of lithium treatment in C57 BL/6J mice, urine volume increased in LiCl-treated mice by fourfold compared with controls (P < 0.0001) and was accompanied by decreased urine osmolality. This was temporally associated with increased renal COX2 protein expression and increased urinary PGE(2) excretion, whereas COX1 levels remained unchanged. COX2 inhibition significantly blunted lithium-induced polyuria (P < 0.0001) and reduced urinary PGE(2) levels. Lithium-associated polyuria was also seen in COX1-/- mice and was associated with increased urinary PGE(2). COX2 inhibition completely prevented polyuria and PGE(2) excretion in COX1-/- mice, suggesting that COX2, but not COX1, plays a critical role in lithium-induced polyuria. Lithium also induced renal medullary COX2 protein expression in congenitally polyuric antidiuretic hormone (AHD)-deficient rats, demonstrating that lithium-induced COX2 protein expression is not secondary to altered ADH levels or polyuria. Lithium also decreased renal medullary GSK-3beta activity, and this was temporally related to increased COX2 expression in the kidney from lithium-treated mice, consistent with a tonic in vivo suppression of COX2 expression by GSK-3 activity. In conclusion, these findings temporally link decreased GSK-3 activity to enhanced renal COX2 expression and COX2-derived urine PGE(2) excretion. Suppression of COX2-derived PGE(2) blunts lithium-associated polyuria.

Adjuvants, Immunologic↗
PubMed2004

SERCA structural dynamics induced by ATP and calcium.

We have used time-resolved phosphorescence anisotropy (TPA) to probe rotational dynamics of the rabbit skeletal sarcoplasmic reticulum Ca-ATPase (SERCA), to test the hypothesis, generated from X-ray crystallography, that large-scale structural changes are induced by Ca in this system. Previous TPA studies on SERCA used primarily erythrosin 5'-isothiocyanate (ErITC), which binds to the nucleotide-binding domain and inactivates the enzyme. To investigate rotational dynamics of the active enzyme, we labeled SERCA with erythrosin 5'-iodoacetamide, which binds to the phosphorylation domain and has a minimal effect on the calcium-dependent ATPase activity. In the absence of nucleotide and the presence of calcium, TPA results were similar to those observed previously with ErITC, consistent with the global uniaxial rotation of SERCA monomers and oligomers and small amplitude internal protein dynamics. The removal of Ca had only a slight effect, while the addition of adenosine 5'-triphosphate (ATP) increased the amplitude of internal dynamics and changed the probe's orientation, corresponding to tilting of the phosphorylation domain by at least 20 degrees . Ca partially reversed the ATP effects. A nonhydrolyzable ATP analogue had the same effects as ATP, showing that the observed changes were not dependent on active ion transport. Computational analysis indicates that these ligands affect primarily the internal dynamics of the enzyme, with negligible effects on global dynamics and enzyme association. Melittin, which has been shown to aggregate and inhibit SERCA, eliminated the nucleotide-induced internal dynamics and increased the final anisotropy. We propose that (i) the large Ca-dependent structural changes suggested by SERCA crystallography are more dependent on ATP than on Ca and (ii) aggregation-induced inhibition of SERCA is due to the functional coupling between global and internal protein dynamics.

Adenosine Triphosphate↗
PubMed2004

Nerve regeneration and wound healing are stimulated and directed by an endogenous electrical field in vivo.

Biological roles for naturally occurring, extracellular physiological electric fields have been proposed over the past century. However, in the molecular era, many biologists presume that electric fields have little physiological relevance because there has been no unequivocal demonstration of their importance at the single-cell level in vivo. We have used an in vivo rat corneal model, which generates its own endogenous electric field and show that nerve sprouting, the direction of nerve growth and the rate of epithelial wound healing are controlled coordinately by the wound-induced electric field.

Animals↗
PubMed2004

Synthesis and properties of dimetallic M1[Pz]-M2[Schiff base] complexes.

We report the synthesis and physical characterization of a series of peripherally functionalized porphyrazines (pz's) 1[M(1); M(2); R], where M(1) is a metal ion incorporated into the pz core, M(2) is a metal ion bound to a bis(5-tert-butyl-salicylidenimine) chelate built onto two amino nitrogen attached to the pz periphery, and R is a solubilizing group (either n-propyl (Pr) or 3,4,5-trimethoxyphenyl (TMP) group) attached to the remaining carbons of the pz periphery. The 1[M(1); M(2); R] species are prepared from precursor pz's with a selenodiazole ring; they are deprotected to form the diamino pz, which reacts with two moles of 5-tert-butyl-2-hydroxybenzaldehyde to form the Schiff base pz. This is metalated to form 1[M(1); M(2); R]. The crystal structures of 1[2H; Ni; Pr] and 1[Cu; ClMn; Pr] are presented. The EPR spectra of the M(1)-M(2) "isomers" prepared with Cu(II) (S = (1)/(2)) and ClMn(III) (S = 2) ions, 1[ClMn; Cu; Pr] and 1[Cu; ClMn; TMP], are a superposition of spectra expected for the S = (3)/(2) and S = (5)/(2) total-spin manifolds that result from strong Heisenberg coupling between the partner spins. The exchange splitting between the two manifolds, as determined by temperature-dependent magnetic susceptibility measurements, is equivalent for the two M(1)-M(2) "isomers", Delta/k(B) approximately 20-25 K, which suggests a sigma-pathway for exchange coupling.

Journal Article↗
PubMed2004

DC electric fields induce distinct preangiogenic responses in microvascular and macrovascular cells.

OBJECTIVE: Electrical stimulation induces significant angiogenesis in vivo. We have shown recently that electrical stimulation induces directional migration, reorientation, and elongation of macrovascular endothelial cells. Because angiogenesis occurs mainly in the microvasculature, we have extended this observation to include human microvascular endothelial cells (HMEC-1s) and compared the responses with that of vascular fibroblasts and smooth muscle cells and human umbilical vein endothelial cells. METHODS AND RESULTS: Four types of vascular cells were cultured in electric fields (EFs). Dynamic cell behaviors were recorded and analyzed with an image analyzer. EFs of 150 to 400 mV/mm induced directed migration, reorientation, and elongation of all the vascular cells. HMEC-1s showed the greatest directional migration (migration rate of 11 microm/h and directedness of 0.35 at 200 mV/mm). Most intriguingly, HMEC-1s migrated toward the cathode, whereas the other cell types migrated toward the anode. CONCLUSIONS: Endothelial cells derived from angiogenic microvascular as opposed to nonangiogenic macrovascular tissues were more responsive to electrical stimulation. This intriguing directional selectivity indicates that a DC electrical signal as a directional cue may be able to play a role in the spatial organization of vascular structure.

Animals↗
PubMed2004

Identification of multivesicular bodies as prevacuolar compartments in Nicotiana tabacum BY-2 cells.

Little is known about the dynamics and molecular components of plant prevacuolar compartments (PVCs). We have demonstrated recently that vacuolar sorting receptor (VSR) proteins are concentrated on PVCs. In this study, we generated transgenic Nicotiana tabacum (tobacco) BY-2 cell lines expressing two yellow fluorescent protein (YFP)-fusion reporters that mark PVC and Golgi organelles. Both transgenic cell lines exhibited typical punctate YFP signals corresponding to distinct PVC and Golgi organelles because the PVC reporter colocalized with VSR proteins, whereas the Golgi marker colocalized with mannosidase I in confocal immunofluorescence. Brefeldin A induced the YFP-labeled Golgi stacks but not the YFP-marked PVCs to form typical enlarged structures. By contrast, wortmannin caused YFP-labeled PVCs but not YFP-labeled Golgi stacks to vacuolate. VSR antibodies labeled multivesicular bodies (MVBs) on thin sections prepared from high-pressure frozen/freeze substituted samples, and the enlarged PVCs also were indentified as MVBs. MVBs were further purified from BY-2 cells and found to contain VSR proteins via immunogold negative staining. Similar to YFP-labeled Golgi stacks, YFP-labeled PVCs are mobile organelles in BY-2 cells. Thus, we have unequivocally identified MVBs as PVCs in N. tabacum BY-2 cells. Uptake studies with the styryl dye FM4-64 strongly indicate that PVCs also lie on the endocytic pathway of BY-2 cells.

Androstadienes↗
PubMed2004

The development of new density gradient media for purifying human islets and islet-quality assessments.

Successful islet transplantation is dependent on the quality and quantity of islets infused. Islets are purified on density gradients, but procedures currently used have limited capacity for pancreatic digests, islet yield, and viability. We aimed to improve islet purification with a modified gradient medium. Biocoll was diluted in University of Wisconsin solution to create linear density gradients of 1.065 to 1.095 g/mL. Properties of islets purified from 22 human pancreas digests with modified medium were compared with 15 preparations using standard medium. The modification increased the capacity of gradients for pancreatic digests from 20 to 60 mL, islet yield increased from 218,000 to 435,318 per isolation, and viability increased from 65.4% to 92.1%. Islet fractions contained greater than 95% of recovered insulin. Islets showed good physiologic responses to secretagogues and restored normoglycemia in streptozotocin-induced diabetic severe combined immunodeficiency disease mice. The new medium enhances yield, purity, and viability of human islet preparations for clinical islet transplantation.

Adenosine↗
PubMed2004

[Characterization of peripheral dendritic cell subsets and its implication in patients infected with severe acute respiratory syndrome].

OBJECTIVE: To investigate the dynamic changes of dendritic cell subsets in peripheral blood of patients infected with severe acute respiratory syndrome (SARS) and evaluate their roles in the immunopathogenesis of SARS. METHODS: Flow cytometry was applied to study the dynamic alteration of the number and frequencies in circulating DC cell subsets in 30 SARS patients including critical SARS (n = 11) and general SARS (n = 19). The reasons and clinic significances of the peripheral blood DC subsets changes in SARS patients were also analyzed in our study. RESULTS: The patients in critical status had a 9-week course of disease, longer than the 6-week course observed in subjects in general status. The frequency of peripheral DC cell subsets significantly dropped beginning from the onset of symptom in SARS patients and was maintained at significant low levels during the following 4 - 5 weeks, 1.7 +/- 1.8, 5.3 +/- 5.0/ micro l for DC1, 0.57 +/- 1.02, 0.98 +/- 1.11/ micro l for DC2 for cases in critical and general statuses, respectively, compared with healthy subjects; more importantly, the pDC2 even disappeared in the patients who died from SARS diseases. The possible reasons responsible for the alteration of DC subsets in peripheral blood is likely to be the direct attack of SARS-CoVin circulation and be partially involved the application of large dose of steroid. The frequency in DC cell subsets returned to normal level in convalescent stage. CONCLUSION: Our results showed SARS patients had a significant decrease of circulating DC cell subset frequency, which maybe lead to the host immunodeficiency response to SARS-associated coronavirus (SARS-CoV).

Adult↗
PubMed2004

Insulin, not leptin, promotes in vitro cell migration to heal monolayer wounds in human corneal epithelium.

PURPOSE: To investigate the effects of insulin and leptin on in vitro wound healing of transformed human corneal epithelial cell monolayers and to identify cellular (migration versus proliferation) and intracellular signaling mechanisms. METHODS: Scratch wounds were created in monolayers of an immortalized human corneal epithelial cell (HCEC) line. The wounded monolayers were exposed to insulin and leptin. Wound areas were measured every hour after wounding for up to 8 hours. Phosphoinositide 3-kinase (PI3-kinase) and mitogen-activated protein (MAP)-kinase signaling was analyzed with Western blot. The actions of insulin were also examined after incubation with inhibitors to extracellular signal regulated kinase (ERK 1/2) and PI3-kinase. RESULTS: The presence of insulin, but not leptin facilitated closure of wounds created in corneal epithelial cell monolayers. Phosphorylation of ERK 1/2 and Akt was stimulated after exposure of the monolayers to insulin. Inhibitors of PI3-kinase and ERK 1/2 prevented or reduced insulin-induced corneal wound healing, respectively. CONCLUSIONS: Exposure of corneal epithelium to insulin facilitated closure of in vitro small wounds through enhanced cell migration instead of proliferation, which depended on ERK 1/2 and PI3-kinase signaling. These data suggest a mechanism by which insulin may influence corneal wound healing in vitro. In vivo, disruptions to the insulin signaling pathway observed in diseases such as diabetes might account for the delayed wound healing and corneal defects.

Blotting, Western↗
PubMed2004

Overexpression of gastrin and c-met protein involved in human gastric carcinomas and intestinal metaplasia.

Many studies have investigated the expression of c-met and c-erbB2 protein in human gastric adenocarcinomas, but the expression of gastrin protein in human gastric cancer and the relationship between gastrin and c-met are unknown. We have constructed a tissue microarray containing 408 formalin-fixed and paraffin-embedded human tissue blocks, including tissues containing intestinal metaplasia (IM, n=72) and primary tumors (n=232), as well as normal gastric mucosa (n=104) from patients with gastric cancer. Immunohistochemistry (IHC) was used for detecting gastrin, c-met and c-erbB2 proteins. Gastrin was detected in 13.5% (7/52) and c-met in 15.3% (11/72) of IM cases. In gastric carcinomas, 48.4% (103/213) of cases expressed gastrin, 68.8% (148/215) expressed c-met, and 5.5% (11/200) expressed c-erbB2. Gastrin and c-met protein expression were significantly higher in gastric tumor tissue than in IM (P<0.0001). Overexpression of c-erbB2 protein was detected in gastric carcinomas but not in normal gastric mucosa (P<0.05). Expression of gastrin and c-met protein was associated (P<0.01), but no significant difference was found on the changes of gastrin, c-met and c-erbB2 expression in gastric cancer with tumor stage, grade of differentiation or tumor type. These results indicate that gastrin and c-met play a role in the early process during malignant transformation of the gastric mucosa.

Adenocarcinoma↗
PubMed2004

Characterization of a new type HPV16 E7 variant isolated from cervical cancer highest incidence area in Hubei Province of China.

AIM: To investigate the variation and biological properties of HPV16 E7 isolated from cervical cancer biopsy samples from highest incidence area in HuBei province of China. METHODS: HVP16 E7 sequences isolated from the cervical cancer biopsies of 10 local patients were amplified, sequenced and compared with prototype E7 gene. Then the variant gene was cloned into different vectors to study the antigenicity, expression and immunogenicity of its protein by Western blot, immunofluorescence and genetic immunization in vitro or in vivo. RESULTS: The results showed that 7 of 10 samples had the same mutations which led to a nonsense mutation at codon 43 of E7 sequence. The truncated E7 protein could be recognized by standard E7 monoclonal antibody in Western blot and expressed in NIH3T3 cells. In the blood sera of mice immunized intramuscularly by the plasmid DNA expressing the variant E7 gene specific E7 antibodies could be detected at week 2, 3, 5 and 6 after inoculation. However, no specific lymphoproliferation after E7 protein stimulation in vitro was detected by MTT colorimetric assay in comparison to the prototype E7 protein. CONCLUSION: HPV16 E7 gene may show variation in China and the variant protein could be expressed and induce host humoral immune response, but could not elicit special cellular-immune response against it. These data might hold the key for future development of HPV16 vaccine in HuBei province of China.

Animals↗