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Biomedical subjects

L W Huang

Publications and source records attributed to L W Huang.

At least 19 recordsLinked to original sources
PubMed2006

Three dimensional reconstruction of the pancreas based on the virtual Chinese human--female number 1.

OBJECTIVE: To study the three dimensional (3D) reconstruction and 3D visualisation of the pancreas and create anatomy of the digitalised visual pancreas so as to construct a concrete basis for virtual operation and surgical operation on pancreas. METHODS: The digital imaging data of pancreas, duodenum, common bile duct, arteries, and veins were obtained from the virtual Chinese human--female 1 (VCH-F1). The image data were investigated and 380 images ascertained of pancreas picked up from images numbers 2617 to 2996. Finally, the images from number 2574 to 3017 were adopted to segment and processed using ACDSee and Photoshop so as to reconstruct 3D pancreas digitally. The data of pancreatic surfaces were transformed into Visualization Toolkit (VTK). The GUI program written with VC+ was used to display this VTK file and realise 3D visualisation of the pancreas. RESULTS: 3D reconstruction and visualisation of the pancreas and the peri-pancreatic structures (the duodenum, the common bile duct,the inferior vena cava, the portal vein vessels, the aorta, the coeliac trunk vessels) was successful. The 3D and visualised pancreas manifested itself with its complete structure as well as its adjacency to other tissues. CONCLUSION: The 3D reconstruction and 3D visualisation of the pancreas based on the digital data of VCH-F1 produces a digitally visualised pancreas, which promises a novel method for virtual operation on the pancreas, clinical operation on the pancreas, and anatomy of 3D visualised pancreas.

Arteries↗
PubMed2005

Self-organized growth of nanopucks on Pb quantum islands.

Electronic Moirè patterns found on lead (Pb) quantum islands can serve as a template to grow self-organized cluster (nanopucks) arrays of various materials. These patterns can be divided into fcc- and hcp-stacked areas, which exhibit different binding strengths to the deposited adatoms. For Ag adatoms, the binding energy can differ substantially and the confined nucleation thus occurs in the fcc sites. Both the size distribution and spatial arrangement of the Ag nanopucks are analyzed and found to be commensurate with the characteristics of the template island, which exhibits a bilayer oscillatory behavior.

Journal Article↗
PubMed2001

Decrease of muscarinic M2 cholinoceptor gene expression in the heart of aged rat.

It is well known that the baroreflex activity decreases with aging. However, the mechanisms of this change are still not clear. Thus, we investigated one of the parameters to see whether aging alters gene expression of muscarinic receptors in the heart of Wistar rat aged between 2 months (adult) and 24 months (aged). The mRNA level determination by Northern blot analysis for muscarinic M2 cholinoceptors in aged rat was decreased as compared to that in 2-month-old rats. Quantification of receptor protein using selective antibodies indicated that the level of muscarinic M2 cholinoceptor in the heart of 24-month-old rats was lower than that in 2-month-old animals. These results indicate the decrease of muscarinic M2 cholinoceptor in heart with aging that may contribute as one of the parameters for dysfunction in baroreflex activity.

Aging↗
PubMed2001

p53 and p21 expression in precancerous lesions and carcinomas of the uterine cervix: overexpression of p53 predicts poor disease outcome.

OBJECTIVES: Abnormal expression of the p53 and p21(waf1/cip1) tumor suppressor genes has been observed in a variety of human tumors, but little is known about its expression during cervical tumorigenesis. To identify the potential implications of both genes in the development of cervical carcinoma and explore the clinical importance of changes in gene expression, we assessed the levels of both proteins in precancerous lesions and carcinomas of the cervix. METHODS: In our study, 10 low-grade squamous intraepithelial lesions (LSIL), 35 high-grade squamous intraepithelial lesions (HSIL), 12 microinvasive carcinomas, and 103 invasive carcinomas were evaluated. The expression of p53 and p21 was studied by immunohistochemistry using monoclonal antibodies specific for these proteins. RESULTS: p21 was expressed in all samples of normal epithelium, LSIL, and HSIL, and the mean values of expression were 50.3, 42.5, and 44.5%, respectively. Conversely, the expression of p21 was significantly reduced in microinvasive (30.7%) and invasive carcinomas (9.9%). p53 nuclear staining was not detected in normal epithelium samples or LSILs, while 4 (11.4%) of 35 HSILs, 1 (8.3%) of 12 microinvasive carcinomas, and 38 (36.9%) of 103 invasive carcinomas were positive for p53. Compared with the results of the control group, precancerous lesions, and microinvasive carcinoma, the mean value of p53 expression (4.8%) in invasive carcinoma was significantly higher. Furthermore, p53 overexpression was significantly associated with advanced stage of the tumor (P < 0.001) [16/67 (23.9%) stage I, 15/28 (53.6%) stage II, and 7/8 (87.5%) stage III/IV]. In univariate analysis, p53 overexpression was a significant predictor of poor survival, whereas it had no independent influence on overall survival using the Cox regression method. Our data also revealed that no association between p53 immunostaining and p21 expression was found. CONCLUSIONS: The trend of reduced p21 expression in microinvasive and invasive carcinomas suggests that p21 may play a tumor-suppressor function in neoplastic transformation in cervical epithelium and inactivation of p21 may be an early event in cervical carcinogenesis. Our results indicated that p53 overexpression was a significant predictor of poor disease outcome in univariate analysis. Moreover, significantly increased expression of p53 in advanced-stage cervical carcinoma implies that inactivation of p53 is associated with tumor progression. Finally, this study further supports the notion that induction of p21 expression can be regulated in a p53-independent manner.

Adult↗
PubMed2001

Development of a sandwich ELISA test for arginase measurement based on monoclonal antibodies.

Human arginase was purified from liver and two monoclonal antibodies (MAbs), HA1 and HA2, were produced by fusion of spleen cells from an arginase-immunized BALB/c mouse and the NS-1 myeloma cell line. Both MAbs were of the IgG3 subclass and contained the kappa light chain. HA1 inhibited arginase activity, suggesting that it binds to the arginase catalytic site. HA1 and a horseradish peroxidase-conjugated polyclonal rabbit anti-human arginase antibody were used to develop a sandwich enzyme-linked immunoadsorbent assay (ELISA) for the quantification of human arginase, which can be used in the 1 to 300 ng/mL range. Because of its sensitivity and specificity, this MAb can be successfully applied to the ELISA quantification of arginase in serum and culture supernatants.

Antibodies, Monoclonal↗
PubMed2001

Arginase levels are increased in patients with rheumatoid arthritis.

Arginase and nitric oxide synthase (NOS) compete for the same substrate, L-arginine. The reciprocal regulation of arginase and NOS in L-arginine-metabolizing pathways has recently been demonstrated. Since NOS is involved in the inflammation of human arthritides, we hypothesized that this reciprocal regulation might also occur within the inflamed synovium. The present study shows that both serum arginase activity and protein levels were significantly higher in patients with rheumatoid arthritis (RA) than in patients with systemic lupus erythematosus (SLE) or osteoarthritis (OA) or in healthy controls. Arginase protein concentrations in supernatants of monocyte cultures from RA patients were also significantly higher than in those from SLE or OA patients or healthy controls. In RA patients, there was a significant correlation between the serum concentrations of arginase protein and rheumatoid factor (r = 0.82, p < 0.0001). These data indicate that increased arginase production is seen in RA patients, but not in other immune-related diseases, suggesting that increased arginase production is unique to, and may play an important role in, the pathogenesis of RA disease.

Arginase↗
PubMed2000

Gene expression of alpha(1A)-adrenoceptor but not alpha(1B)-adrenoceptor in cultured myoblast C(2)C(12) cells of mice.

Subtypes of alpha(1)-adrenoceptor (alpha(1)-AR) in the cultured myoblast C(2)C(12) cells have been examined using molecular biological identifications. Expression of the two distinct mRNAs that encode proteins of alpha(1A)- and alpha(1B)-AR was studied using reverse transcription combined with polymerase chain reaction (RT-PCR). Results of RT-PCR demonstrated a marked expression of alpha(1A)-AR in the prostate of rats. Samples from the C(2)C(12) cells under the same amount of amplification showed the expression of alpha(1A)-AR at a level slightly lower than that from the prostate of rats. Western blotting analysis using receptor subtype-specific antibody also indicated that the alpha(1A)-AR was expressed in C(2)C(12) cells as well as in prostate of rats. However, although the expression of alpha(1B)-AR was obtained in the spleen of rats, expression of alpha(1B)-AR was undetectable in the C(2)C(12) cells either the results of RT-PCR or the Western blotting analysis. The present study suggests that alpha(1A)-AR is a major subtype of alpha(1)-AR in the C(2)C(12) cell line.

Animals↗
PubMed2000

Analysis of p73 in human borderline and invasive ovarian tumor.

p73 is a novel gene that has high sequence homology and similar gene structure to the tumor suppressor gene p53. We analysed p73 in seven ovarian carcinoma cell lines and a total of 63 human borderline and invasive ovarian tumor samples. Loss of heterozygosity at this locus was observed in 50% of invasive tumors but in none of the borderline tumors. Biallelic expression of the gene was observed in the heterozygous tumor tissues. Direct sequencing and single-strand conformation polymorphism analyses of the p73 cDNA sequence homologous to the highly mutatable region of p53 did not reveal any mutations. When compared to the primary cultures of normal human ovarian surface epithelial cells and immortalized cell lines, four of the seven ovarian carcinoma cell lines, 71% of the invasive tumors, and 92% of the borderline tumor tissues express elevated levels of p73 transcript. Except for the OVCA3 cell line, Western blot analysis of the nuclear extracts prepared from the cell lines showed concordant levels of p73 protein. Our analysis also demonstrated the expression of a spliced variant of p73 transcript with the omission of exon 2 solely in the cancer cell lines and invasive tumor tissues. This exon 2-spliced transcript would give rise to a truncated p73 protein without the N-terminal transactivation domain. In reminiscence of the dominant negative phenotype of the N-terminal truncated variants of another p53-related gene, p63, the expression of the truncated p73 variant form in ovarian tumors may play an important role in the pathogenesis of ovarian cancer.

Amino Acid Sequence↗
PubMed2000

BRCA1-related papillary serous carcinoma of the peritoneum has a unique molecular pathogenesis.

Papillary serous carcinoma of the peritoneum (PSCP) is believed to develop de novo from the peritoneal lining of the pelvis and abdomen. Although it is histologically indistinguishable from serous ovarian carcinoma, PSCP exhibits minimal or absent ovarian involvement and may even develop in a woman years after prophylactic oophorectomy. We have shown previously that patients with germ-line BRCA1 mutations who develop PSCP are more likely to have disease originating from multiple peritoneal sites compared with patients with wild-type BRCA1. In this study, we tested the hypothesis that BRCA1-related PSCP has a unique molecular pathogenesis. DNA was extracted from normal tissue and multiple tumor sites in patients with PSCP. BRCA1 and p53 gene mutations were screened for using single-strand conformation polymorphism. Loss of heterozygosity was determined at the BRCA1 and p53 loci. Immunohistochemical analyses of p53, epidermal growth factor receptor, erbB-2, erbB-3, erbB-4, and Bcl-2 expression were performed. We detected germ-line BRCA1 mutations in 11 (26%) of 43 PSCP patients. BRCA1 mutation carriers had a higher overall incidence of p53 mutations (89% versus 47%; P = 0.052), were more likely to exhibit multifocal or null p53 mutations (63% versus 7%; P = 0.014), and were less likely to exhibit erbB-2 overexpression (P = 0.013) than wild-type BRCA1 case subjects. We propose that the unique molecular pathogenesis of BRCA1-related PSCP may affect the ability of current methods to reliably prevent or detect this disease prior to metastasis.

BRCA1 Protein↗
PubMed2000

Differential expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 protein and mRNA in epithelial ovarian tumors.

OBJECTIVE: Matrix metalloproteinase-9 (MMP-9) can degrade gelatin and type IV collagen and is known to play an important role in tumor cell invasion across the basement membrane. The tissue inhibitor of metalloproteinase-1 (TIMP-1) is able to prevent activation of pro-MMP-9 and forms a 1:1 complex with the active form of MMP-9. The aim of the present study was to investigate the expression of MMP-9 and TIMP-1 in benign, borderline, and invasive epithelial ovarian tumors. MATERIALS AND METHODS: A total of 90 patients with epithelial ovarian tumor were treated at the Brigham and Women's Hospital and were used as the study population. Immunohistochemistry and in situ hybridization were performed to detect protein and mRNA expression of MMP-9 and TIMP-1. RESULTS: In the 90 epithelial ovarian tumors tested, MMP-9 expression in tumor cells was found to be significantly enhanced in serous and mucinous ovarian carcinomas compared with benign and borderline tumors. We also observed the immunostaining of MMP-9 in stromal cells of benign, borderline, and invasive epithelial ovarian tumors. Moreover, the expression levels of TIMP-1 in tumor cells were significantly higher in borderline and invasive ovarian tumors than in benign tumors. CONCLUSION: Using an in situ hybridization technique, we disclosed a direct correlation between the presence of mRNA and protein expression for both MMP-9 and TIMP-1. The present data suggest that high levels of MMP-9 protein in invasive epithelial ovarian carcinoma are strongly associated with tumor cell invasion. Enhanced expression of TIMP-1 protein in borderline and invasive tumors indicates that endogenous TIMP-1 protein may play a paradoxical role in ovarian tumor progression.

Cystadenocarcinoma, Mucinous↗
PubMed2000

Bcl-2 and p53 protein expression, apoptosis, and p53 mutation in human epithelial ovarian cancers.

Bcl-2 and p53 gene products have been both linked to cell death by apoptosis. In the present study, we examined the relationship of Bcl-2 and p53 protein expression, p53 mutation and apoptosis in normal human ovaries and different types of human ovarian epithelial tumors by immunohistochemical localization, in situ terminal transferase-mediated dUTP nick end labeling and polymerase chain reaction-single strand conformation polymorphism. It was found that Bcl-2 expressed strongly in the surface epithelium of normal ovaries and benign and borderline ovarian tumors but weakly in the malignant tumors. On the contrary, strong protein expression of p53 was found in 54% (25/46) of the malignant epithelial tumors examined but similar expression of p53 was not observed in borderline and benign tumors and normal ovarian surface epithelium. A significant inverse correlation between Bcl-2 and p53 expression was found in the malignant ovarian tumors examined. p53 gene mutation at exons 5-11 was however not a pre-requisite for p53 expression in both borderline and malignant tumors. Apoptotic activities, as reflected by apoptotic indices, were low in normal ovarian surface epithelium and benign tumors but were increased in borderline and malignant tumors, with the highest average apoptotic index found in grade III malignant tumors. Statistical analyses showed a positive correlation between apoptosis and p53 expression, but similar correlation was not found between apoptosis and Bcl-2 expression. Our results also indicate that although expression of Bcl-2 is important during ovarian carcinogenesis, the Bcl-2 protein may have other roles to play apart from being a modulator of apoptosis in human ovarian epithelial cancers.

Apoptosis↗
PubMed2000

Identification of a novel 9 cM deletion unit on chromosome 6q23-24 in papillary serous carcinoma of the peritoneum.

To define regions of deletion on chromosome 6q in papillary serous carcinoma of the peritoneum (PSCP), we analyzed 103 tumor tissues from 53 patients by using 11 polymorphic microsatellite markers spanning loci from 6q23 to 6q27. Allelic losses on 6q were observed in 42 of 53 (79.2%) cases. We identified 3 distinct regions with a high percentage (>40%) of loss of heterozygosity. The first region is located at 6q23-24 and defined by D6S311 (15 of 35 informative cases, 42.9%). Detailed deletion mapping of chromosome 6q23-24 in these tumor samples identified a novel 9 cM minimal deletion region flanked by D6S250 and ESR. The second one is located at 6q25.1-25.2 and defined by D6S448 (17 of 36 informative cases, 47.2%). A second minimal deletion region of 4 cM was flanked by D6S420 and D6S442. The third region is located at 6q27 and defined by D6S297 (9 of 19 informative cases, 47.4%). Comparing these results with our cases of advanced staged invasive serous epithelial ovarian carcinoma (SEOC), we observed that allelic losses at D6S311 (6q23) and D6S149 (6q27) were significantly higher for PSCP than for SEOC. The pattern of allelic loss at each tumor site within an individual patient was also studied. A total of 36 cases displayed allelic loss for at least 1 of multiple tumor sites, and 35 of these patients exhibited nonidentical patterns of allelic loss at various tumor sites of the same patient. Furthermore, an alternating pattern of allelic loss in the same patient was identified in 3 of 53 patients studied. These results show that allelic losses on 6q are very frequent in PSCP, and we show 2 discrete minimal deletion regions on 6q, suggesting the existence of at least 2 tumor suppressor genes within 6q that may be involved in the pathogenesis of PSCP. In addition, the finding of different patterns of allelic loss at different tumor sites within the same patient indicate a mutifocal origin in some PSCP cases. These results provide strong evidence to support our previous reports that PSCP is a multifocal disease entity.

Chromosome Deletion↗
PubMed2000

Distinct allelic loss patterns in papillary serous carcinoma of the peritoneum.

Tumor and normal tissues from 55 patients with papillary serous carcinoma of the peritoneum (PSCP) were analyzed. Polymerase chain reaction amplification of tandem repeat polymorphism was used to screen for loss of heterozygosity (LOH). We mapped 22 oligonucleotide primers to chromosomes 1p, 3p, 6q, 7q, 9p, 11p, 17p, 17q, and Xq. Germline BRCA1 mutation status of 43 patients was determined previously. High frequencies (> 30%) of LOH in PSCP were observed on 6q, 9p, 17p, 17q, and Xq. Compared with allelic loss of serous epithelial ovarian carcinoma (SEOC), the frequency of LOH was significantly lower in PSCP on 1p, 7q, 11p, 17p, and 17q. Of 43 cases screened for germline BRCA1 mutations, 9 cases were identified with mutations. The frequencies of LOH were not significantly different among the BRCA1-related and BRCA1-unrelated PSCP cases. The high LOH rate identified on 6q, 9p, 17p, 17q, and Xq in PSCP suggests that candidate tumor suppressor genes residing in these regions may be important for the development of the tumor. Compared with allelic loss of SEOC, PSCP exhibits a significantly lower frequency of LOH on chromosomes 1p36, 7q31.3, 11p15.1, 17p13.1, and 17q21. An increase in susceptibility to the acquisition of allelic loss in BRCA1-related PSCP cannot be identified.

Alleles↗
PubMed1999

A comparison between loop electrosurgical excision procedure and cold knife conization for treatment of cervical dysplasia: residual disease in a subsequent hysterectomy specimen.

OBJECTIVE: The purpose of this study was to determine whether the loop electrosurgical excision procedure (LEEP) is as effective as cold knife conization (CKC) in the removal of cervical dysplasia. METHODS: One-hundred sixteen patients with cervical intraepithelial neoplasia were included: 73 cases treated with LEEP and 43 cases treated with CKC. All of these patients underwent subsequent hysterectomy within 6 months of treatment. A thorough histological evaluation of the cone specimens and post-cone hysterectomy specimens was performed. RESULTS: No residual disease in the post-cone hysterectomy specimens was identified in 63% of the LEEP group and 72.1% of the CKC group. There was no significant difference in the proportion of negative residual disease (P > 0.05). The mean diameters of the base as well as the depth of the cone specimens were smaller in the LEEP group than in the CKC group (P < 0.05). The operating time in the LEEP group was significantly shorter than that of the CKC group (P < 0.05). Although thermal artifacts of margin were found in 8.2% of LEEP specimens, there was no difficulty in histological interpretation. Furthermore, the postoperative complications were similar in both groups. CONCLUSION: The findings of this study demonstrate that the LEEP is a convenient, safe, and effective treatment for the management of cervical dysplasia. Cone specimens obtained during LEEP are adequate for thorough histological evaluation of cervical dysplasia.

Adult↗
PubMed1999

Synthesis and characterization of pH-sensitive dextran hydrogels as a potential colon-specific drug delivery system.

pH-Sensitive dextran hydrogels were prepared by activation of dextran (T-70) with 4-nitrophenyl chloroformate, followed by conjugation of the activated dextran with 4-aminobutyric acid and cross-linking with 1,10-diaminodecane. The cross-linking efficiencies determined by mechanical measurements were in the range of 52-63%. Incorporation of carboxylpropyl groups in dextran hydrogels led to a higher equilibrium and faster swelling under high pH conditions. The swelling reversibility of hydrogels was also observed after repeated changes in buffers between pH 2.0 and 7.4. The slow rates of swelling and deswelling in response to changes in pH were attributed to the hydrophilic nature of dextran and formation of hydrogen bonds between the hydroxyl groups of dextran with water molecules. The pronounced effect of carboxylic acid content on degradation of hydrogels was observed after 4 h of incubation with dextranase and the influence significantly decreased after exposure to the enzyme for 8 h. The mechanism of bulk degradation of hydrogels under high swelling extent was substantiated using Coomassie blue protein assay. The release rate of bovine serum albumin from hydrogels was primarily determined by the swelling extent. The release rate was further enhanced by addition of dextranase in buffer solutions.

Colonic Diseases↗
PubMed1995

Sphingolipid-gated Ca2+ release from intracellular stores of endothelial cells is mediated by a novel Ca(2+)-permeable channel.

Sphingolipid-gated Ca2+ signaling is mediated through Ca(2+)-permeable channels. In this report, we characterize the properties of the channel in a human endothelial cell line (EA.hy926). Ca2+ release from intracellular stores is not antagonized by nifedipine, omega conotoxin G-VIa, or heparin. To further characterize the molecular properties of the channel, we developed a novel assay to directly measure efflux of Ca2+ from intracellular stores of permeabilized Xenopus oocytes. Following size fractionation by sucrose gradient, poly(A)+ RNA from EA.hy926 cells is microinjected into oocytes of Xenopus laevis. We find that the mRNA encoding Ca2+ release activity is approximately 1.5-2.0 kilobases in length. The sphingolipid-gated Ca(2+)-permeable channel is thus likely to be a novel Ca(2+)-permeable channel distinct from other characterized intracellular Ca2+ channels such as the ryanodyne receptor and the inositol 1,4,5-trisphosphate receptor. The method described here provides a new approach to further characterizing this channel and other intracellular Ca2+ channels.

Animals↗
PubMed1992

Gestational and congenital syphilis in Hualien.

From September 1987 to April 1991, 19 pregnant women (0.97%) with syphilis were detected out of 1,955 pregnant women who received prenatal serologic screening at the Buddhist Tz'u-Chi General Hospital. The ages ranged from 17 to 34 years (average, 26). Three cases had recurrent gestational syphilis. The time of diagnosis was: the third trimester, 11 cases; the second trimester, six cases; and the first trimester, two cases. The reasons for late (third trimester) diagnosis were: delay of prenatal care, four cases; failure to screen syphilis in the pregnancy, four cases; and negative first test and late infection, three cases. Late diagnosis and treatment often resulted in poor fetal outcome: syphilitic stillbirth, two cases; probable and possible congenital syphilis, seven cases; and normal infant, two cases. Patients (delivered, five; undelivered, two; abortion, one) who had been diagnosed before the third trimester had a better fetal outcome: possible congenital syphilis, one case; and normal infant, four cases. The perinatal mortality and morbidity were significantly higher in the late diagnosis group (9/11) than in the early diagnosis group (1/5). Pregnant women should be screened in early pregnancy by a serologic test for syphilis. In areas of high prevalence, or in patients at high risk, screening should be repeated in the third trimester and again at delivery.

Adolescent↗