Biomedical subjects

W Zhao

Publications and source records attributed to W Zhao.

At least 163 records · Page 9Linked to original sources

PubMed2000

[Microsurgical treatment of large or giant aneurysms in anterior circle of Willis].

OBJECTIVE: To improve the operative results in large or giant aneurysms of the anterior circle Willis. METHODS: Retrospective analysis was performed on 28 patients with large or giant aneurysms of the anterior circle Willis after operation. Three-D CT angiography was used to detect and delineate aneurysm preoperatively. Improved operative technique included cranial base approach, temporary artery occlusion, intra-aneurysm decompression, obliteration of aneurysm with multiple clips, stepwise coagulation clipping and resection of aneurysms. RESULTS: Good results were noted in 24 patients (85.7%), fair in 2, and poor in 1. One patient died, but no patient with Hunt and Hess 0-III grade died. CONCLUSIONS: Three-D CT angiography is useful in delineating the shape, size, neck of aneurysms, and their relation to near arteries and to cranial base structures. These are helpful to improve operative results of large or giant aneurysms of the anterior circle of Willis.

Adult↗

PubMed2000

[Mechanism of tissue factor expression on NB4 cells down-regulated by all-trans retinoic acid and arsenic trioxide].

OBJECTIVE: To investigate molecular mechanism of tissue factor (TF) expression on acute promyelocytic leukemia cell line NB4 cells down-regulated by all-trans retinoic acid (ATRA) and arsenic trioxide (As(2)O(3)). METHODS: Cyclohexamide (CHX) inhibition test for de novo protein synthesis and actinomycin D (Act D) inhibition test for RNA synthesis were used to check the effect of ATRA on the TF expression. TF antigen of U937 cells transfected with pMSCV-PML-RARalpha treated with or without ATRA and As(2)O(3) was detected. RESULTS: CHX treatment completely suppressed the down-regulation effect of ATRA on the TF mRNA expression, Act D inhibition test showed that half-life of TF mRNA in treated NB4 cells was shortened to about 30 min from that of around 60 min in untreated NB4 cells. The TF antigen contents in U937 cells transfected with pMSCV-PML-RARalpha were significantly higher than that in transfected U937 cells with retrovirus vector. Both ATRA and As(2)O(3) could down-regulate the TF antigen level in U937 cells transfected with or without PML-RARalpha. CONCLUSION: The modulation of the TF mRNA expression in NB4 cells by ATRA might be indirect. TF mRNA destabilization was involved in the TF regulation process mediated by ATRA. Elevated TF antigen level in U937 cells transfected with pMSCV-PML-RARalpha may be related to the fusion protein PML-RARalpha. The down-regulation effect of ATRA and As(2)O(3) on the TF expression of U937 cells might not involve the fusion protein.

Antineoplastic Agents↗

PubMed2000

[Hemostatic variations associated with acute leukemia: clinical and prognostic significance].

OBJECTIVE: To study the hemostatic abnormalities and their association with bleeding manifestation and prognosis in acute leukemia (AL) patients. METHODS: A series of hemostatic parameters were determined in 93 cases of AL using ELISA or chromogenic assay. RESULTS: At diagnosis, plasma levels of P-selectin, soluble fibrinomonomer complex (SFMC), thrombomodulin (TM), tissue plasminogen activator, D-dimer (D-D) were significantly elevated, but protein C antigen (PC:Ag), plasminogen (PLG), alpha(2)-antiplasmin (alpha(2)-PI) and plasminogen activator inhibitor (PAI) were decreased, and fibrinogen (Fg), PC activity (PC:A) and protein S (PS) were in normal range. All the above abnormalities returned to normal after complete remission (CR) except for PC:A and PC:Ag. Platelet counts, Fg, SFMC, PLG, alpha(2)-PI and D-D were significantly associated with hemorrhagic manifestations. TM, PS and PAI were related to prognosis. CONCLUSION: There existed the consumption of platelets as well as the activation of coagulant, anticoagulant and fibrinolytic systems in AL, which was greatly improved after CR.

Acute Disease↗

PubMed2000

[Plasmid pcDNA3 enhances Ca(2+) transport of sarcoplasmic reticulum in ischemic skeletal muscle of rats].

The effects of plasmid pcDNA3 on Ca(2+) transport of sarcoplasmic reticulum (SR) in ischemic skeletal muscle was investigated. The results show that Ca(2+) transport (including Ca(2+) uptake and Ca(2+) release) rate of SR in ischemic skeletal muscle was markedly increased compared with that in non-ischemic muscle (P<0.01 or P<0.05). After plasmid pcDNA3 bound to the DNA binding proteins of SR, Ca(2+) transport of SR was further increased. The results suggest that the effect of plasmid DNA on the ability of Ca(2+) transport in SR of ischemic skeletal muscle is the same as is observed in normal skeletal muscle. The pathophysiological significance of the present finding deserves further exploration.

Animals↗

PubMed2000

Basic fibroblast growth factor increases nitric oxide and endothelin production in rat aorta.

The study was undertaken to investigate the effect of basic fibroblast growth factor (bFGF) on aortic production of nitric oxide (NO) and endothelin of aorta in spontaneously hypertensive rats (SHR) and WKY rats. Rat aortas were cut into vessel slices and incubated with 10 or 100 ng/ml bFGF for 6 hours. Nitric oxide synthase (NOS) activity in aortic slices and contents of NO(-)(2) and endothelin in the medium were determined. The results showed that NOS activity in aortic slices of SHR was 17.6% lower than that of WKY (P<0.01). NO(-)(2) and endothelin contents in the medium of SHR aortic slices were 59.7% lower and 37.4% higher than those of WKY aortic slices. Upon the exposure of low and high doses of bFGF, NOS activity in the aorta of SHR was increased by 29.7% and 59.6% (both P<0.01),respectively, while the NO(-)(2) contents in the medium were increased respectively by 28.2% (P<0.05) and 70.5% (P<0.01). Aortic endothelin production was increased by 24.1% and 44.5% (both P<0.01) respectively while the NOS activity in the aorta of WKY was increased by 24.4% and 53.7% (both P<0.01). NO(-)(2) contents in the medium were augmented by 18.8% (P<0.05)and 25.9% (P<0.01), respectively. Aortic endothelin production was increased by 84.1% and 93.1% (both P<0.01). It is concluded that bFGF may modulate the production of NO and endothelin in both SHR and WKY rats.

Animals↗

PubMed2000

[Oncocytic carcinoma of salivary gland].

OBJECTIVE: To study the histological and immunohistochemical characteristics of oncocytic carcinoma of salivary gland. METHODS: 7 cases of oncocytic carcinoma of salivary gland were investigated by HE, PAS, PTAH staining and immunohistochemistry. RESULTS: Among the cases, 4 were male and 3 were female. The average age was 49 years old. 3 cases occurred in the parotid, 1 cases in submandibular, 1 cases in sublingual and 2 cases in minor salivary gland of palate. Investigated histologically, the tumour cells are characterized by oncocyte. The evidence of cellular atypia, obviously increased mitoses and infiltrative growth pattern are indicative of malignancy. Immunohistochemically, alpha 1-ACT, alpha 1-AT, LF, TF and CEA were all strongly positive in the normal salivary cells and adenolymphoma, while in oncocytic carcinoma, alpha 1-ACT and alpha 1-AT were moderate positive and LF, TF and CEA were light positive. CONCLUSION: 7 cases were characterized by oncocyte and showing infiltrative growth, alpha 1-ACT, alpha 1-AT, LF, TF, CEA were positive in oncocyte.

Adenocarcinoma↗

PubMed2000

[Gene cloning and characterization of mitochondria-related protein of Schistosoma japonicum].

OBJECTIVE: To subclone and characterize a cDNA clone coding for Schistosoma japonicum (S.j.) mitochondria-related protein. METHODS: The open reading frame of the fragment(Sj338/24) obtained from an adult worm cDNA library of S.j. was analysed, at the upstream and downstream of the open reading frame(ORF) the primers A and B were designed, respectively, and the cDNA fragment was used as PCR template. The Sj338 gene fragment obtained was amplified by PCR method and then subcloned into pGEM-T vector for sequencing. The gene sequence was analyzed and the target fragment was restrictedly digested and subcloned into expression vector pGEX-6P-1. The expressed recombinant protein was purified and characterized. RESULTS: The cloned Sj338 gene was demonstrated to be 487 bp long containing one 459 bp ORF, encoding a protein with a molecular weight of 17 kDa. The nucleotide sequence of the cloned gene Sj338 had higher homology with those genes coding for mitochondrial outer membrane protein of Homo sapiens and Rattus norvegicus. The recombinant construct of pGEX-6P-1/Sj338 could be expressed efficiently and the antigenicity of its product rSj338 has been demonstrated by Western blotting. CONCLUSION: Sj338 may be the gene coding for S.j. mitochondria-related protein and the recombinant protein may be used as a new vaccine candidate.

Amino Acid Sequence↗

PubMed2000

[Supracricoid subtotal laryngectomy for the treatment of advanced laryngeal cancers].

OBJECTIVE: This procedure was designed to eradicate the advanced laryngeal carcinomas while preserving the laryngeal physiologic function. The indications and contraindications for the operation were also discussed and evaluated in this paper. METHODS: Twenty-one patients with advanced laryngeal cancers underwent this procedure during the period from 1988 through 1996 in our department. All of the patients were not amenable to conventional partial horizontal and vertical laryngectomies. In those patients, there were 9 supraglottic cancers, 10 glottic cancers and 2 transglottic cancers. Among them, 16 cases had stage T2 lesions and 5 cases had stage T3 lesions. In this procedure, the hyoid and thyroid cartilages were excised in toto, along with both true and false vocal cords, paraglottic space as well as the partial or total epiglottis and the whole preepiglottic space. The cricoid cartilage and at least one arytenoid cartilage were spared. The new larynx was reconstructed by suturing the cricoid and/or epiglottis to the base of the tongue. RESULTS: Of 21 patients, 95% were able to eat normally without aspiration, 90% were decannulated with near normal speech function. In two patients, the tracheotomy tube was reserved, one developed a stenosis, and another had recurrent aspiration pneumonia. No patients experienced local recurrence. Nineteen patients were followed up for at least 3 years, 13 patients achieved 5 years tumor-free survival. CONCLUSION: The term supracricoid subtotal laryngectomy best describes the surgical approach and the reconstruction model of the new larynx. As a useful alternative to total laryngectomy in selected advanced laryngeal cancers, this procedure may greatly improve the quality of life and prolong the life without recurrence.

Adult↗

PubMed2000

[Effect of weight loss on adipose tissue distribution and insulin sensitivity].

OBJECTIVE: To discuss the effect of weight reduction on fat distribution and parameters of insulin sensitivity. METHODS: 12 Caucasian women with simple obesity, aged 21 to 65 years, were treated by low caloric and high protein diet for four weeks. A series of examinations were taken before and after the treat, using computerized tomography for visceral and subcutaneous fat, using euglycemic insulin clamp for parameters of insulin sensitivity. RESULTS: Weight loss was (6 +/- 2) kg (2-11 kg). body mass index (BMI), waist, total fat, visceral fat, and subcutaneous fat reduced significantly. However waist-hip rate, visceral-total fat rate, and subcutaneous-total fat rate did not change significantly. Fasting serum insulin, and fasting insulin-glucose rate decreased significantly. Insulin metabolic clearance rate and, insulin sensitive index increased significantly. Fasting peptide C did not change significantly. CONCLUSIONS: The low caloric and high protein diet can reduce visceral and subcutaneous fat. Weight loss can improve insulin sensitivity and increase insulin metabolic clearance rate.

Adipose Tissue↗

PubMed1999

Brain insulin receptors and spatial memory. Correlated changes in gene expression, tyrosine phosphorylation, and signaling molecules in the hippocampus of water maze trained rats.

Evidence accumulated from clinical and basic research has indirectly implicated the insulin receptor (IR) in brain cognitive functions, including learning and memory (Wickelgren, I. (1998) Science 280, 517-519). The present study investigates correlative changes in IR expression, phosphorylation, and associated signaling molecules in the rat hippocampus following water maze training. Although the distribution of IR protein matched that of IR mRNA in most forebrain regions, a dissociation of the IR mRNA and protein expression patterns was found in the cerebellar cortex. After training, IR mRNA in the CA1 and dentate gyrus of the hippocampus was up-regulated, and there was increased accumulation of IR protein in the hippocampal crude synaptic membrane fraction. In the CA1 pyramidal neurons, changes in the distribution pattern of IR in particular cellular compartments, such as the nucleus and dendritic regions, was observed only in trained animals. Although IR showed a low level of in vivo tyrosine phosphorylation, an insulin-stimulated increase of in vitro Tyr phosphorylation of IR was detected in trained animals, suggesting that learning may induce IR functional changes, such as enhanced receptor sensitivity. Furthermore, a training-induced co-immunoprecipitation of IR with Shc-66 was detected, along with changes in in vivo Tyr phosphorylation of Shc and mitogen-activated protein kinase, as well as accumulation of Shc-66, Shc-52, and Grb-2 in hippocampal synaptic membrane fractions following training. These findings suggest that IR may participate in memory processing through activation of its receptor Tyr kinase activity, and they suggest possible engagement of Shc/Grb-2/Ras/mitogen-activated protein kinase cascades.

3T3 Cells↗

PubMed1999

An intragenic deletion of nuclear localization signal-1 of p53 tumor suppressor gene results in loss of apoptosis in murine fibroblasts.

We established mouse lines containing either full-length wild-type p53 or nuclear localization signal-I (NLS-I) deleted p53 to study the role of NLS-I in p53 translocation and function. Induction of apoptosis in response to DNA damage, a primary function of p53, was tested in these cell lines. After exposure to gamma-ionizing radiation or hydrogen peroxide, DNA ladders and labeling of nucelosomal fragments were detected in cells with wild-type p53 gene, but not in p53 null cells or NLS-I deleted cells, suggesting that the NLS-I of p53 protein is necessary for apoptosis. Analysis of p53 protein from subcellular fractions indicated that NLS-I deprived p53 remained in the cytoplasmic fraction, which may explain why NLS-I deleted p53 failed to induce apoptosis.

Animals↗

PubMed1999

Defects in the generation of IFN-gamma are overcome to control infection with Leishmania donovani in CC chemokine receptor (CCR) 5-, macrophage inflammatory protein-1 alpha-, or CCR2-deficient mice.

We investigated the immune responses in mice lacking CCR2, CCR5, or macrophage inflammatory protein-1 alpha (MIP-1 alpha), a ligand for CCR5, in two situations: following T cell stimulation or after challenge with Leishmania donovani, an intracellular microbe whose control is dependent on a Th1 immune response. Mice deficient in CCR5, MIP-1 alpha, or CCR2 had reduced IFN-gamma responses following ligation of the TCR. Reduced IFN-gamma responses following PMA and ionomycin were also observed in CD8+ T cells of CCR5-/- and CCR2-/- mice. During the early phases of infection, all three knockout mice had low Ag-specific IFN-gamma responses. However, this reduced IFN-gamma response was overcome during a state of persistent Ag stimulation (chronic infection), and was not associated with an adverse parasitologic outcome in any of the gene-targeted mouse strains. To the contrary, during the late phase of infection, an exaggerated Ag-specific IFN-gamma response was evident in CCR5-/- and MIP-1 alpha-/- mice, and this correlated with an enhanced control of parasite replication. Although granuloma formation was abnormal in each of the knockout mice, there was no correlation between the number or architecture of the granulomas and parasite burden. Collectively, these findings indicate an important role for CCR5, MIP-1 alpha, and CCR2 in granulomatous inflammation, and that CCR5 and MIP-1 alpha, possibly acting through CCR5, might play a deleterious role in the outcome of chronic L. donovani infection. Our data also suggest that there might be cross-talk between TCR and chemokine receptor signaling pathways.

Animals↗

PubMed1999

Neuroprotective effect of high-dose albumin therapy against global ischemic brain injury in rats.

The purpose of this study was to determine whether treatment with high-dose human serum albumin (HSA) would offer protection in a model of high-grade transient forebrain ischemia. Twenty-six fasted Wistar rats underwent bilateral common carotid artery occlusion and severe hypotension (50 mmHg) for 10 min. The agent (25% HSA) or vehicle (0.9% NaCl) was administered i.v. 5 min after termination of ischemia. HSA-treated rats showed significantly improved neurological deficits throughout a 7-day survival period. Histologically, HSA-treated rats showed 2.4- to 5.3-fold increases in numbers of surviving CA1 hippocampal pyramidal neurons compared to saline-treated animals. These results document that high-dose albumin therapy instituted 5 min after global ischemia significantly improves neurological score and reduces histological damage.

Albumins↗

PubMed1999

Dendritic cell (DC)-based anti-infective strategies: DCs engineered to secrete IL-12 are a potent vaccine in a murine model of an intracellular infection.

Infections with intracellular pathogens such as Leishmania donovani and Mycobacterium tuberculosis pose serious health problems worldwide. Effective vaccines for these pathogens are not available. Furthermore, despite optimal therapy, disease progression is often seen with several intracellular infections. For these reasons, we initiated studies to develop novel anti-infective vaccine and treatment strategies that couple the potent Ag-presenting capacity of dendritic cells (DC) with paracrine delivery of potent anti-infective cytokines such as IL-12 to local immune response sites. We tested this strategy in a murine model of visceral leishmaniasis. Adoptive transfer of DCs pulsed ex vivo with soluble L. donovani Ags (SLDA) to naive mice induced the Ag-specific production of IFN-gamma, and increased the percentage of activation markers on spleen lymphocytes. SLDA-pulsed DCs engineered by retroviral gene transfer techniques to secrete high levels of biologically active murine IL-12 augmented this immune response further. In several different vaccination and immunotherapy protocols, compared with sham-treated mice, animals receiving SLDA-pulsed DCs either before or following infection had 1-3 log lower parasite burdens, and this protection was associated with a pronounced enhancement in the parasite-specific IFN-gamma response. The augmentation of this protection by IL-12-engineered DCs was striking. First, live parasites were not detected in the liver of mice vaccinated with IL-12-transduced, SLDA-pulsed DCs. Second, this parasitological response was associated with a nearly normal liver histology. In contrast, parasites and granulomas were found in mice vaccinated with SLDA-pulsed, nontransduced DCs. Collectively, these studies provide the rationale for the development of potent DC-based immunotherapies.

3T3 Cells↗

PubMed1999

Middle cerebral artery occlusion in the mouse by intraluminal suture coated with poly-L-lysine: neurological and histological validation.

The present study was conducted to validate a modified method of temporary focal cerebral ischemia in the mouse; neurobehavioral function and histopathological infarction were quantitated following various periods of middle cerebral artery occlusion (MCAo). Male C57BL/6 mice were anesthetized with 3% halothane in a mixture of 30%O2/70%N2O delivered by face mask and were subjected to 30- to 180-min of temporary middle cerebral artery occlusion (MCAo) by an intraluminal suture coated with poly-l-lysine. Twenty-eight of 40 mice showed an initial high-grade neurological deficit (30-min MCAo, n=7; 60-min, n=8; 120-min, n=8; 180-min, n=5) when examined during MCAo; these were used for subsequent study. One day after MCAo, behavioral function was re-evaluated, and brains were perfusion-fixed and infarct volumes were measured. The initial neurological deficit improved at 24 h in mice with 30- or 60-min of prior MCAo but tended to persist in mice with 120- or 180-min insults. Following each duration of ischemia, mice exhibited ipsilateral infarcts. Small, inconsistent predominantly subcortical infarcts were present after 30-min MCAo, while longer occlusion periods gave rise to consistent foci of subcortical infarction involving striatum, septum, thalamus, and hippocampus, as well as areas of frontoparietal cortical infarction. The major advantages of the improved intraluminal MCAo model reported here, incorporating sutures coated with poly-l-lysine, include: a 100% incidence of infarction of predictable location and size in mice having an initial neurological deficit. Periods of 60- to 180-min MCA occlusion in this model yield sufficiently reproducible sequelae to permit the effects of various therapeutic agents on neurological outcome and size of infarction to be readily studied.

Animals↗

PubMed1999

Quantitation of multiple gene expression by in situ hybridization autoradiography: accurate normalization using Bayes classifier.

In the method of in situ hybridization autoradiography, quantitative comparisons among multiple mRNA signals have proven difficult for many reasons, attributable both to technical factors (e.g. different probe specific activities) as well as to large differences in the patterns and levels of expression of different genes in pathologic states. Here we report a standardized normalization procedure for in situ hybridization autoradiography, employing a Bayes classifier, which permits the comparison of multiple mRNA probes. Autoradiograms of different probes in individual animals are first digitized and converted to units of radioactivity. Next, pixel-distribution histograms are generated for each mRNA signal. The Bayes classifier is then used to establish an optimal threshold to distinguish activated and non-activated pixels. This threshold also defines the minimal level of mRNA expression. The maximal mRNA signal is defined as the mean + 3 SD of the activated pixel distribution. We then use a linear transformation to convert each pixel from absolute activity to percentage of maximal mRNA signal for that particular probe. The normalized autoradiographic images can then be averaged to represent group trends and can be compared by standard statistical methods. We illustrate this normalization procedure using in situ hybridization autoradiography for three genes (GADD45, HSP70 and MAP2) expressed in the brains of rats studied at various recirculation times following transient (2 h) middle cerebral artery occlusion. The Bayes classifier is reviewed and its analytical application is presented. Step-by-step examples of intermediate steps are presented, construction of averaged data sets, and pixel-based statistical comparisons among expressed genes.

Animals↗

PubMed1999

Changes in phosphorylation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) in processing of short-term and long-term memories after passive avoidance learning.

Characteristic autophosphorylation of calcium/ calmodulin-dependent protein kinase II (CaMKII) and its consequences have made this kinase an interesting target in studying the molecular pathway for important neuronal functions including learning and memory formation. In this article, we use immunoprecipitation and immunoblotting methods to detect changes in phosphorylation of CaMKII during memory formation in 1-day-old chicks trained in a single trial passive avoidance task. A 60-kDa protein has been immunoprecipitated from the chick brain with an anti-rabbit CaMKII antibody. This protein shows strong and specific immunoactivities with antibodies against the calmodulin binding site of CaMKII, and the N and C terminals of beta-CaMKII. Commercially available anti-phosphoserine and anti-phosphothreonine antibodies are shown to sensitively detect phosphorylation of purified CaMKII. The basal phosphorylation of CaMKII from the intermediate medial hyperstriatum ventrale (IMHV) and lobus parolfactorius (LPO) regions of the chick brain is shown to be largely right hemisphere-lateralized. When chicks are subjected to a passive avoidance training experience, a specific increase in CaMKII phosphorylation is induced in the IMHV and LPO of the left hemisphere from those chicks whose memory for the training experience is successfully retrieved. While this specific increase in CaMKII phosphorylation is seen in both the left IMHV and left LPO in short-term memory, it is detectable only in the left LPO associated with long-term memory retrieval. The present results provide evidence that in vivo changes in phosphorylation of CaMKII are associated specifically with processing of distinct memory stages, which take place in specific brain regions.

3T3 Cells↗

PubMed1999

Characterization of the fibronectin binding motif for a unique mycobacterial fibronectin attachment protein, FAP.

Studies were performed to define the fibronectin binding motif of the previously identified Mycobacterium avium fibronectin attachment protein (FAP-A). Using synthetic peptides of a previously identified fibronectin binding region (amino acids 269-292), the minimal binding sequence was determined to be 12 amino acids, 269-280 (FAP-A-(269-280)). Synthetic peptides were prepared in which each amino acid in the 269-280 sequence was substituted with Ala. Assessment of the effect of Ala substitution on fibronectin binding showed that the presence of Ala at amino acids 273-276 (RWFV) completely abrogated fibronectin binding activity. Furthermore, the ability to inhibit the attachment of viable Mycobacterium bovis BCG to fibronectin was abrogated by Ala substitution at the RWFV sites. To validate the function of RWFV, further studies were performed with recombinant FAP-A in which single Ala mutations were generated for the RWFV sites and as controls at amino acids 269 and 280. Mutant FAP-A containing single Ala substitutions at the RWFV sites (amino acids 273, 274, 275, or 276) showed significant abrogation of fibronectin binding function. Recombinant FAP-A with Ala substitutions at either 269 or 280 showed wild type activity. When the four essential amino acids (RWFV) were either substituted en bloc with Ala or were all deleted, complete loss of fibronectin binding function was observed. Control recombinant proteins with en bloc Ala substitutions or deletions at four positions outside the fibronectin binding region (amino acids 255-257) retained functional activity. These data show that the RWFV sequence is necessary for fibronectin binding function of FAP-A. Furthermore, the data suggest that mycobacterial FAP proteins, all of which share the RWFV binding motif, constitute a family of highly homologous proteins that bind fibronectin in a unique manner.

Adhesins, Bacterial↗