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Biomedical subjects

Z Liu

Publications and source records attributed to Z Liu.

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

Islet-1 expression and its colocalization with luteinising hormone, thyroid-stimulating hormone and oestrogen receptor alpha in the developing pituitary gland of the sheep foetus.

Islet-1 has been reported to be involved in pituitary development in the early stages of mouse embryogenesis. Oestrogen receptor (ER) and its expression may be involved in regulating pituitary development and its hormone-secreting function. Islet-1 expression and its correlations to ER in the developing pituitary gland are unknown. We therefore determined the pituitary cell specific expression of Islet-1 and its colocalization with ER alpha (ERalpha) in sheep foetus by immunohistochemistry. The results demonstrated that Islet-1-immunoreactive (ir) cells were distributed throughout the pituitary gland from day 60 of gestation until birth. The Islet-1-ir cell number was significant higher at day 90 and 120 of gestation compared to that at day 60 and at birth. All of the ERalpha-ir cells were colocalized with Islet-1 at day 60 of gestation, although a few ERalpha-ir cells were negative for Islet-1 in the later stage of gestation. The dominant cell type expressing Islet-1 is the gonadotroph, although small proportions of thyrotrophs and lactotrophs also express Islet-1. The proportion of luteinising hormone-ir gonadotrophs possessing Islet-1 kept rising from day 60 to day 120 of gestation and persisted until birth. The proportion of thyroid-stimulating hormone-ir cells expressing Islet-1 was at a high level from day 60-120 of the gestation and significantly declined at birth. The percentage of prolactin (PRL)-ir cells expressing Islet-1 was about 20% at day 60 of gestation. Very few PRL-ir cells contained Islet-1 in later stages of gestation. These data suggest that the development and functional establishment of pituitary gonadotrophs, thyrotrophs and lactotrophs might be regulated by the expressions of Islet-1 and ERalpha and by their interactions, although any mechanisms need to be elucidated further.

Animals↗
PubMed2005

Hot-spot mutations in hepatitis B virus core gene: eliciting or evading immune clearance?

The biological implications of substitutions L60V and I97L in the core (c) gene of hepatitis B virus (HBV) were investigated in order to determine whether they could change the immunogenicity of HBcAg or influence the immune response in mice. Three strains of recombinant adenoviruses--AdHBV-WT, AdHBV-L60V and AdHBV-I97L--containing wild-type or mutant HBV genomes were constructed using the AdEasy system and used to infect BALB/c mice intranasally. Infected mice produced anti-HBc efficiently to comparable levels. IgG1 and IgG2a specific for HBcAg were present in mice sera, and the response was dominated by IgG2a. The lymphocyte proliferative response specific for HBcAg was assessed by [3H]-thymidine uptake. We found that AdHBV-WT induced a stronger T-cell proliferation response than AdHBV-L60V and AdHBV-I97L. In conclusion, the L60V and I97L substitutions had no influence on humoral immune responses, but could downregulate T-cell responses to HBcAg, suggesting that L60V and I97L were immune escape mutants.

Animals↗
PubMed2005

HLA-DPA1 promoter haplotypes are differently distributed in southern Chinese ethnic groups.

DPA1 gene is one of the human leukocyte antigen (HLA) class II genes and its promoter is highly polymorphic. From comparative studies among five southern Chinese populations, Jing, Li, Bai, Lahu, and Meizhou Han, we describe their single-nucleotide polymorphism (SNP)/haplotype frequency data of HLA-DPA1 gene promoter in this study. Within the 760-bp promoter region, we have identified 21 SNPs and nine possible haplotypes. Pair-wise comparisons show similar frequencies distribution of the HLA-DPA1 promoter haplotypes among Jing, Li, and Bai, whereas all pair-wise comparisons involved with Lahu or Meizhou Han and other ethnic groups show remarkable difference. The differences in frequencies of HLA-DPA1 promoter alleles may reveal different ethnic origins and demographic histories of the five populations. Our study may help distinguishing each of these populations by sequence variations of HLA-DPA1 promoter, which may be served as functional molecular markers for clinical and immunological studies involving the DPA1 locus.

Alleles↗
PubMed2005

Polymorphism of human leukocyte antigen-DRB1, -DQB1, and -DPB1 genes of Shandong Han population in China.

In the present study, polymerase chain reaction-sequence-based typing (PCR-SBT) was used to analyze human leukocyte antigen (HLA)-DRB1, -DQB1, and -DPB1 alleles of 98 unrelated healthy Shandong Han individuals. A total of 60 alleles, in which 28 in DRB1, 15 in DQB1 and 17 in DPB1 were found. Among the 28 detected DRB1 alleles, DRB1*150101, DRB1*070101, DRB1*090102, DRB1*120201, and DRB1*080302 were commonly observed, with frequencies of 16.3%, 11.2%, 10.2%, 8.2%, and 5.6%, respectively. The most predominant DQB1 allele was DQB1*030101/0309 with the frequency of 20.4%, followed by DQB1*0201/0202 (14.8%), DQB1*0602 (14.3%), DQB1*030302 (12.2%), and DQB1*060101/060103 (10.7%). Of the 17 detected DPB1 alleles, DPB1*0501 was the most frequent allele with the frequency of 37.2%. DPB1*020102 (18.4%), DPB1*040101 (11.2%), DPB1*0402 (7.1%), and DPB1*1701 (6.6%) were also very frequent alleles. A total of 53 estimated DRB1-DQB1 two-locus haplotypes were observed in Shandong Han population, of which DRB1*150101-DQB1*0602 was the most predominant, followed by DRB1*090102-DQB1*030302, DRB1*070101-DQB1*0201/0202 DRB1*120201-DQB1*030101/0309, and DRB1*080302- DQB1*060101/060103. The distribution of the HLA class II alleles and haplotypes frequencies as well as the dendrogram showed that the Shandong Han population belongs to the northern group of Chinese. The data have implications for anthropological studies and disease associations.

Alleles↗
PubMed2005

Tight junctions, leaky intestines, and pediatric diseases.

BACKGROUND: Tight junctions (TJs) represent the major barrier within the paracellular pathway between intestinal epithelial cells. Disruption of TJs leads to intestinal hyperpermeability (the so-called "leaky gut") and is implicated in the pathogenesis of several acute and chronic pediatric disease entities that are likely to have their origin during infancy. AIM: This review provides an overview of evidence for the role of TJ breakdown in diseases such as systemic inflammatory response syndrome (SIRS), inflammatory bowel disease, type 1 diabetes, allergies, asthma, and autism. CONCLUSION: A better basic understanding of this structure might lead to prevention or treatment of these diseases using nutritional or other means.

Celiac Disease↗
PubMed2005

Lower urinary tract function in patients with pituitary adenoma compressing hypothalamus.

BACKGROUND: The micturition reflex is under the tonic influence of suprapontine structures including the anteromedial frontal cortex, basal ganglia, and hypothalamus. However, there have been few reports about the role of the hypothalamus on the lower urinary tract (LUT) function in humans. OBJECTIVE: To investigate LUT function in patients with pituitary adenomas. METHODS: Urodynamic studies were carried out in three patients with LUT symptoms who had pituitary adenomas extending upwards to the hypothalamus. RESULTS: All three male patients (age 28 to 62 years) developed LUT symptoms (urinary urgency and frequency (3); urinary incontinence (3); voiding difficulty and retention (2)) along with weight loss, psychiatric symptoms, unsteady gait, and/or visual disturbances. One had the syndrome of inappropriate secretion of antidiuretic hormone, but none had diabetes insipidus. Two had resection of the tumour and subsequent radiation therapy, but LUT dysfunction persisted. The third patient had partial resection of the tumour to ameliorate hydrocephalus. Urodynamic studies showed detrusor overactivity during the storage phase in all patients; during the voiding phase there was underactive detrusor in two and non-relaxing sphincter in one. CONCLUSIONS: Hypothalamic lesions can cause severe LUT dysfunction in both the storage and voiding phases of micturition. This may reflect the crucial role of the hypothalamus in regulating micturition in humans.

Adenoma↗
PubMed2005

Lower urinary tract function in dementia of Lewy body type.

OBJECTIVE: Dementia of Lewy body (DLB) type is the second commonest degenerative cause of dementia and autonomic dysfunction has been recognised in DLB. Lower urinary tract (LUT) function in DLB has not been fully delineated. We investigated LUT function in DLB by evaluating clinical and urodynamic data. METHODS: We examined 11 patients (eight men, three women; age range 65-81; disease duration 2-14 years) with probable DLB. Urodynamic studies consisted of: measurement of postvoid residual in all patients, uroflowmetry in five, and electromyography (EMG) cystometry in seven. RESULTS: All patients had symptoms of LUT: urinary incontinence (urgency type/functional type due to dementia and immobility/both urgency and stress type in 7/2/1 patients, respectively); night-time frequency; urgency; and daytime frequency and voiding difficulty. Seven had postvoid residuals, and three had residual urine volume >100 ml. Decreased urinary flow was seen in all five and detrusor overactivity in 5/7 patients who underwent flowmetry and EMG cystometry, respectively. Low compliance detrusor (storage phase, n = 2; with bethanechol supersensitivity), an underactive detrusor (n = 4), an acontractile detrusor (n = 1), and detrusor-sphincter dyssynergia (voiding phase) (n = 1) were also seen; 2/3 patients who underwent motor unit potential analysis had neurogenic changes. CONCLUSION: LUT dysfunction is a common feature in DLB, not only due to dementia and immobility, but also to central and peripheral types of somato-autonomic dysfunction.

Aged↗
PubMed2005

When is Onuf's nucleus involved in multiple system atrophy? A sphincter electromyography study.

BACKGROUND: External anal sphincter (EAS) electromyography (EMG) abnormalities can distinguish multiple system atrophy (MSA) from Parkinson's disease in the first five years after disease onset. However, the prevalence of the abnormalities in the early stages of MSA is unknown. OBJECTIVES: To present EAS-EMG data in the various stages of MSA. METHODS: 84 patients with "probable" MSA were recruited (42 men, 42 women; mean age 62 years (range 47 to 78); mean disease duration 3.2 years (0.5 to 8.0; <1 year in 25%); 50 cerebellar form (MSA-C), 34 parkinsonian form (MSA-P)). EAS motor unit potential (MUP) analysis and EMG cystometry were carried out in all patients. RESULTS: The overall prevalence of neurogenic change of the EAS MUP was 62%-52% in the first year after disease onset, increasing to 83% by the fifth year (p<0.05); it also increased with severity of gait disturbance (p<0.05), storage and voiding disorders, and detrusor sphincter dyssynergy (NS). The neurogenic change was not correlated with sex, age, MSA-P/C, postural hypotension, constipation, erectile dysfunction in men, underactive or acontractile detrusor, or detrusor overactivity. In 17 incontinent patients without detrusor overactivity or low compliance, urinary incontinence was more severe in those with neurogenic change than in those without (p<0.05). CONCLUSIONS: Involvement of Onuf's nucleus in MSA is time dependent. Before the fifth year of illness, the prevalence of neurogenic change does not seem to be high, so a negative result cannot exclude the diagnosis of MSA.

Aged↗
PubMed2005

Estimation of quantitative trait loci parameters for milk production traits in German Holstein dairy cattle population.

The main objective of this study was to estimate the proportion of total genetic variance attributed to a quantitative trait locus (QTL) on Bos taurus autosome 6 (BTA6) for milk production traits in the German Holstein dairy cattle population. The analyzed chromosomal region on BTA6 spanned approximately 70 cM, and contained 6 microsatellite markers. Milk production data were obtained from routine genetic evaluation for 4500 genotyped German Holstein bulls. Technical aspects related to the estimation of model parameters for a large data set from routine genotype recording were outlined. A fixed QTL model and a random QTL model were introduced to incorporate marker information into parameter estimation and genetic evaluation. Estimated QTL variances, expressed as the ratio of QTL to polygenic variances, were 0.04, 0.03, and 0.07 for milk yield; 0.06, 0.08, and 0.14 for fat yield; and 0.04, 0.04, and 0.11 for protein yield, in the first 3 parities, respectively. The estimated QTL positions, expressed as distances from the leftmost marker DIK82, were 18, 31, and 17 cM for milk yield; 25, 17, and 9 cM for fat yield; and 16, 30, and 17 cM for protein yield in the 3 respective parities. Because the data for the parameter estimation well represented the current population of active German Holstein bulls, the QTL parameter estimates have been used in routine marker-assisted genetic evaluation for German Holsteins.

Analysis of Variance↗
PubMed2005

Antineutrophil cytoplasmic antibodies (ANCA) in Chinese patients with anti-GBM crescentic glomerulonephritis.

OBJECTIVE: To study the prevalence of ANCA and their target antigen in Chinese patients with anti-GBM crescentic glomerulonephritis (CGN), and to evaluate the possible role of ANCA in Chinese anti-GBM CGN patients with coexisting serum ANCA by studying clinicopathologic features of this disease. MATERIAL AND METHODS: Twenty-three sera were collected from 23 renal biopsy-proven anti-GBM CGN patients. According to the standardized procedures, all of the sera were determined by both, indirect immunofluorescence (IIF) ANCA, and enzyme-linked immunosorbent assay (ELISA) MPO-ANCA, PR3-ANCA and BPI-ANCA. The patients were divided into two groups according to serum ANCA positivity (Group A) or negativity (Group B). Thirty-three ANCA-associated pauci-immune CGN patients were regarded as control group (Group C). Their clinicopathologic features were compared to reveal whether ANCA correlated with disease activity. RESULTS: There were 11 (47.8%) cases with positive serum ANCA in 23 anti-GBM glomerulonephritis patients. There were 4/11 MPO-ANCA (one with positive PR3-ANCA and C-ANCA, three with negative IIF-ANCA), 1/11 PR3-ANCA (with positive MPO-ANCA and C-ANCA), 3/11 P-ANCA (with negative ELISA-ANCA) and 5/11 C-ANCA (one with positive PR3-ANCA and MPO-ANCA, and the other four with negative ELISA-ANCA). No BPI-ANCA was detected. No different clinicopathologic features were found between Groups A and B. Both were different from Group C in age, sex ratio, frequence of anuria and ESRD, variety of crescents, glomerular sclerosis, vessel lesion and prognosis. CONCLUSION: Our data demonstrate that ANCA in Chinese patients with anti-GBM CGN is not rare. The major target antigen of ANCA is MPO. ANCA seems not to be correlated with disease activity.

Adolescent↗
PubMed2005

Morphological study of the interaction between M21 melanoma and lymphatic endothelium.

In order to study the interaction between melanoma and lymphatic endothelial cells (LECs) and to investigate the mechanism of lymphatic metastasis, M21 melanoma cells were seeded on the confluent LECs monolayer and the alterations of both cells were observed. The results showed that tumor cells could both adhere by pseudopodia to LECs at the site near the intercellular junction and on the apical surface. The adhesion of the melanoma cells induced the endothelial junction dissolution and endothelial retraction, which allowed the passage of the tumor cells through the opened gap and attached to the subendothelial matrix, then the tumor cells invaded and migrated under the LECs monolayer. These findings suggest that tumor cells could metastasize through the lymphatic vessel by destroying intercellular junctions or the LECs directly.

Animals↗
PubMed2004

Removing a barrier to computer-based outbreak and disease surveillance--the RODS Open Source Project.

INTRODUCTION: Computer-based outbreak and disease surveillance requires high-quality software that is well-supported and affordable. Developing software in an open-source framework, which entails free distribution and use of software and continuous, community-based software development, can produce software with such characteristics, and can do so rapidly. OBJECTIVES: The objective of the Real-Time Outbreak and Disease Surveillance (RODS) Open Source Project is to accelerate the deployment of computer-based outbreak and disease surveillance systems by writing software and catalyzing the formation of a community of users, developers, consultants, and scientists who support its use. METHODS: The University of Pittsburgh seeded the Open Source Project by releasing the RODS software under the GNU General Public License. An infrastructure was created, consisting of a website, mailing lists for developers and users, designated software developers, and shared code-development tools. These resources are intended to encourage growth of the Open Source Project community. Progress is measured by assessing website usage, number of software downloads, number of inquiries, number of system deployments, and number of new features or modules added to the code base. RESULTS: During September--November 2003, users generated 5,370 page views of the project website, 59 software downloads, 20 inquiries, one new deployment, and addition of four features. CONCLUSIONS: Thus far, health departments and companies have been more interested in using the software as is than in customizing or developing new features. The RODS laboratory anticipates that after initial installation has been completed, health departments and companies will begin to customize the software and contribute their enhancements to the public code base.

Disease Outbreaks↗
PubMed2004

Mild and effective N-phthaloylation of amino acids.

In the present work various free amino acids, including tryptophan and tyrosine, were effectively N-phthaloylated under reduced pressure and at lower temperature. Moreover, under these conditions, the presence of phthalic acid in phthalic anhydride did not hinder the N-phthaloylation of amino acids. This simple process is economic, environmentally friendly, and suitable for large-scale production.

Amino Acids↗
PubMed2004

The evolution of H5N1 influenza viruses in ducks in southern China.

The pathogenicity of avian H5N1 influenza viruses to mammals has been evolving since the mid-1980s. Here, we demonstrate that H5N1 influenza viruses, isolated from apparently healthy domestic ducks in mainland China from 1999 through 2002, were becoming progressively more pathogenic for mammals, and we present a hypothesis explaining the mechanism of this evolutionary direction. Twenty-one viruses isolated from apparently healthy ducks in southern China from 1999 through 2002 were confirmed to be H5N1 subtype influenza A viruses. These isolates are antigenically similar to A/Goose/Guangdong/1/96 (H5N1) virus, which was the source of the 1997 Hong Kong "bird flu" hemagglutinin gene, and all are highly pathogenic in chickens. The viruses form four pathotypes on the basis of their replication and lethality in mice. There is a clear temporal pattern in the progressively increasing pathogenicity of these isolates in the mammalian model. Five of six H5N1 isolates tested replicated in inoculated ducks and were shed from trachea or cloaca, but none caused disease signs or death. Phylogenetic analysis of the full genome indicated that most of the viruses are reassortants containing the A/Goose/Guangdong/1/96-like hemagglutinin gene and the other genes from unknown Eurasian avian influenza viruses. This study is a characterization of the H5N1 avian influenza viruses recently circulating in ducks in mainland China. Our findings suggest that immediate action is needed to prevent the transmission of highly pathogenic avian influenza viruses from the apparently healthy ducks into chickens or mammalian hosts.

Animals↗
PubMed2004

Molecular characterization of HMW glutenin subunit allele 1Bx14: further insights in to the evolution of Glu-B1-1 alleles in wheat and related species.

1Bx14 is a member of the high molecular weight (HMW) glutenin subunits specified by wheat Glu-B1-1 alleles. In this work, we found that the full-length amino acid sequence of 1Bx14 and 1Bx20, the last two of the three cysteine residues, which are conserved in 1Bx7, 1Bx17 and homologous 1Ax and 1Dx subunits, were replaced by tyrosine residues. In the 5' flanking regions (-900 to -1,200 bp relative to the start codon), a novel miniature inverted-repeat transposable element insertion was present in 1Bx12 and 1Bx20 but not 1Bx7 and 1Bx17. 1Bx14 and 1Bx20 like alleles were readily found in tetraploid wheat subspecies but not several S genome containing Aegilops species. Phylogenetic analysis showed that the four molecularly characterized Glu-B1-1 alleles (1Bx7, 1Bx14, 1Bx17, 1Bx20) could be divided into two allelic lineages. The lineage represented by 1Bx7 and 1Bx17 was more ancient than the one represented by 1Bx14 and 1Bx20. Combined, our data establish that 1Bx14 and 1Bx20 represent a novel subclass of Glu-B1-1 alleles. Based on current knowledge, potential mechanism involved in the differentiation of two Glu-B1-1 lineages is discussed.

Alleles↗
PubMed2004

Pathogenesis and treatment of neoplastic diseases of the papilla of Vater: Kausch-Whipple procedure with lymph node dissection in cancer of the papilla of Vater.

Cancer of the papilla or the ampulla of Vater appears, from a clinical point of view, to be an intraduodenal or ampullary cancer. An adenoma-dysplasia-carcinoma sequence has been established. In 20%-40% of the patients with an adenoma of the papilla, a cancerous lesion in the adenoma is additionally observed. Oncological resection using a Kausch-Whipple technique or a pylorus-preserving partial pancreatico-duodenectomy (PPPD) offers a 5-year survival probability of between 45% and 65%. The hospital mortality after oncological resection at experienced centers is below 5%. The most frequent treatment-related complication is pancreatic fistula, which occurs in around 20% of the patients. In about 10% of the patients with a pT1 cancer and in 25% to 67% with pT2 and pT3 cancer, lymph node involvement has been observed. Lymph nodes in front of and behind the head of the pancreas are the primary targets for cancer cell disseminations. In more than one-third of the patients, lymph nodes in the inter-aortocaval space and the lymph nodes around the superior mesenteric artery and the nodes in the pancreatic segment of the hepatoduodenal ligament are involved. Therefore, tissue dissection, including, selectively, the N2 lymph nodes, is an essential component of radical surgery for cancer of the papilla. A standard Kausch-Whipple resection or PPPD without a selective extended lymph node dissection, including the interaortocaval and superior mesenteric artery nodes, results in about 30% of the patients having an R2-resection, i.e., with cancer left behind. The long-term survival is determined by the tumor biological factors: (1) absence of lymph node involvement and (2) absence of infiltration into the pancreas. The surgeon's contribution to the cure of cancer of the papilla is to perform an R0-resection with low hospital mortality and low postoperative morbidity. Patients without lymph node involvement, and with absence of infiltration into the pancreas, no lymph vessel invasion, and tumor-negative margins have major benefits from oncological resection in regard to curability of the cancer.

Ampulla of Vater↗