Search PubMed⌕ Search

Biomedical subjects

Peng Zhang

Publications and source records attributed to Peng Zhang.

At least 199 records · Page 11Linked to original sources
PubMed2003

The complete mitochondrial genome of the Chinese giant salamander, Andrias davidianus (Amphibia: Caudata).

The mitochondrial genome of the Chinese giant salamander Andrias davidianus was isolated using the long-and-accurate polymerase chain reaction (LA PCR) method. The sequencing work adopted the shotgun strategy accompanying with seven internal primers to cover the gaps where overlapping clones were not available. The entire mtDNA sequence is 16,503 bp long, with a gene content of 13 protein-coding, two ribosomal RNA and 22 transfer RNA genes, and order identical to that observed in most other vertebrates except for an additional 318 bp non-coding sequence between tRNA-Thr and tRNA-Pro genes. In order to carry out molecular phylogenetic analyses, all 13 protein sequences deduced from whole mitochondrial genomes for eight vertebrate species (six amphibians, two lobe-finned fishes) were combined to a single data set. This data set was refined by the program Gblocks using a stringent parameter setting and then subjected to MP, ML and NJ analyses. Thus phylogenetic relationships among living amphibians were discussed.

Animals↗
PubMed2003

Characterization of a knock-out mutation at the Gc2 locus in wheat.

Gametocidal (Gc) genes, introduced into common wheat from related Aegilops species, are selfish genetic elements that ensure their preferential transmission by inducing chromosomal breaks. Here we report the production and characterization of a knock-out mutation of the Gc2 gene transferred to wheat as a wheat-Aegilops sharonensis T4B-4S(sh)#1 translocation chromosome. In hemizygous Gc2/- condition, gametophytes lacking Gc2 suffer chromosomal fragmentation and produce non-functional gametes, which leads to sporophytic semisterility and exclusive transmission of the Gc2-carrier chromosome. We have identified one putative ethyl methylsulfonate (EMS)-induced Gc2 mutant that restores spike fertility and shows Mendelian segregation. Progeny screening mapped the mutation to the Gc2-carrier chromosome T4B-4S(sh)#1. C-banding and fluorescence in situ hybridization analyses showed that the loss of Gc2 function in the mutant is not due to a terminal deficiency. Analysis of first and second pollen mitoses in Gc2(mut) /- plants and C-banding analysis of testcross progenies showed that no chromosomal breakage occurs in the mutant. No gametophytic chromosomal breakage was observed in heterozygous Gc2(mut) /Gc2 plants, which had fully fertile spikes. These results suggest that Gc2 encodes two agents, one causing chromosomal breaks in gametophytes lacking Gc2 and another that protects the Gc2 carrier from breakage. The EMS-induced Gc2 mutant appears to be a knock-out of the gene encoding the "breaking" agent. These data are a first crucial step toward the molecular understanding of Gc2 action.

Chromosome Breakage↗
PubMed2003

Overexpression of p53 is correlated with stromal invasion in extramammary Paget's disease of the vulva.

Molecular alterations that are associated with clinicopathological features of extramammary Paget's disease of the vulva (PDV) are poorly understood. Consequently, we have investigated whether a correlation exists between overexpression of p53 protein and various clinicopathologic features of PDV. Our study group comprises 10 primary noninvasive PDVs, 3 primary PDVs with minimal invasion, and 1 primary PDV with frank invasion. Recurrence in the form of noninvasive PDV was seen in 4 patients with previously noninvasive PDVs and in 1 patient who previously had PDV with minimal invasion. Metastases to the inguinal lymph nodes were associated with the 1 PDV with frank invasion and 1 of the PDVs with minimal invasion. An immunohistochemical study of p53 expression was performed on paraffin-embedded tissue. Negative p53 immunostaining was seen in all of the primary noninvasive PDVs as well as their recurrences. Positive p53 immunostaining was observed in the invasive as well as the intraepidermal components of all of the primary PDVs with invasion, the metastatic tumors in the inguinal lymph nodes, and the recurrent PDV associated with prior invasion, indicating a possible role of p53 in the progression of PDV. To our knowledge, our observation of p53 overexpression in the intraepidermal component of PDVs associated with invasion is the first to be reported in the literature. This observation may prove helpful in identifying stromal invasion in small biopsies. We also report for the first time an association between high nuclear grade in PDV and the propensity for inguinal lymph node metastasis.

Aged↗
PubMed2003

Efficient replication of cloned African cassava mosaic virus in cassava leaf disks.

A transient viral replication assay for cloned African cassava mosaic virus (ACMV) was developed using cassava leaf disks. TMS60444 leaf disks were transfected using biolistic-mediated inoculation with ACMV clones pKACMVA and pKACMVB, which originate from West Kenya ACMV isolate 844 (ACMV-KE). Viral DNA synthesized de novo was monitored by Southern hybridization with an AV1 DNA probe. By using the methylation-sensitive restriction enzymes DpnI and MboI, it was possible to distinguish between the input DNA (dam-methylated) and the de novo synthesized viral DNA (not methylated). Different media used for pre- and post-culture of inoculated leaf disks significantly affected the efficiency of viral DNA accumulation. Without pre-culture, replicated viral DNA was not detectable. Culture time in optimized medium also affected the accumulation of nascent viral DNA, and the best results were obtained after 4 days pre-culture on CIM medium followed by 4-6 days post-culture in SH medium. Time-course analysis showed that viral DNA replication can persist for 5-6 days post-inoculation. Our results also confirmed that DNA B of ACMV could assist the accumulation of viral DNA in the leaf disks. The novel protocol described here has also been used successfully with other cassava cultivars (MCol22, MCol1505, TME282 and TMS92/0326) and ACMV clones from the ACMV Nigeria isolate (ACMV-NOg).

Base Sequence↗
PubMed2003

Transfer and expression of an artificial storage protein (ASP1) gene in cassava (Manihot esculenta Crantz).

In order to increase the nutritional quality of cassava storage roots, which contain up to 85% starch of their dry weight, but are deficient in protein, a synthetic ASP1 gene encoding a storage protein rich in essential amino acids (80%) was introduced into embryogenic suspensions of cassava via Agrobacterium-mediated gene transfer. Transgenic plants were regenerated from suspension lines derived from hygromycin-resistant friable embryogenic callus lines. Molecular analysis showed the stable integration of asp1 in cassava genome and its expression at RNA level in transformed suspension lines. PCR and Southern analyses proved the transgenic nature of the regenerated plant lines. The expression of asp1 at RNA level was demonstrated by RT-PCR. The ASP1 tetramer could be detected in leaves as well as in primary roots of cultured transgenic plants by western blots. These results indicate that the nutritional improvement of cassava storage roots may be achieved by constitutive expression of asp1 in transgenic plants.

Base Sequence↗
PubMed2003

[Non-improvement after different procedures of prostatectomy].

OBJECTIVE: To analyze the causes of non-improvement after different procedures of prostatectomy. METHODS: Using the urodynamics and other techniques, we examined 84 non-improved patients who had undergone different procedures of prostatectomy. RESULTS: In the TURP group, the main causes of non-improvement included bladder outlet obstruction (84.9%), weak contractility of the detrusor (30.4%), and detrusor instability (DI) (18.2%). In the open group, however, the main causes of non-improvement included detrusor weak contractility (52.9%), DI (35.2%), and bladder outlet obstruction (33.3%). There was significant difference between the two groups according to the Pearson Chi-square test (P = 0.000). The re-obstruction rate in the TURP group was much higher than that in the open group, suggesting that the level of the TURP should be improved. CONCLUSIONS: Different operative procedures yield different non-improvement after prostatectomy gradually. When BPH patients are diagnosed with detrusor weak contractility and DI, prostatectomy should be carefully considered.

Aged↗
PubMed2003

[Selection of the imaging modalities for diagnosis of renal trauma: experience with 74 cases].

OBJECTIVE: To explore the diagnostic approaches and values of the imaging modalities for traumatic renal injuries. METHODS: The clinical records of 74 cases of renal trauma treated in Nanfang Hospital were retrospectively reviewed to assess the diagnostic value of intravenous urography (IVU), type B ultrasonography and computed tomography (CT). RESULTS: The positivity rates by IVU, type B ultrasonography, and CT were 89% (43/49), 80% (55/68) and 100% (51/51) respectively for the diagnosis of renal trauma. CONCLUSION: IVU is rapid and convenient, ultrasonography less costly and invasive, and CT accurate for diagnosis of renal traumas.

Adolescent↗
PubMed2003

Influence of bladder outlet obstruction and detrusor contractility on residual urine in patients with benign prostatic hyperplasia.

OBJECTIVE: To study the relationship between the degree of bladder outlet obstruction (BOO), detrusor contractility and residual urine in patients suffering from benign prostatic hyperplasia (BPH). METHODS: In 181 patients with BPH, degree of BOO, detrusor contractility, residual urine caculated from cathetering combined with the difference between the filling and the voiding were recorded and analysized statistically using urodynamic technique. RESULTS: Residual urine increased when the detusor contractility was weakened (F = 12.134, P = 0.001). In patients wih severe BOO, there was no significant difference in residual urine (F = 2.386, P = 0.071). CONCLUSIONS: Increased residual urine is mainly resulted from decreased detrusor contractility. BOO has no significant influence on residual urine. Some patients with normal or weakened detrusor contractility may have more residual urine.

Aged↗
PubMed2003

[Relationship between expression of BLCAP protein and malignancy of osteosarcoma].

AIM: To study the relationship between expression of bladder cancer-associated protein (BLCAP) and malignancy of osteosarcoma. METHODS: SABC method was applied to study the expression of BLCAP protein in osteosarcoma, according to clinical results, to analyze the prognosis value of BLCAP protein in osteosarcoma. RESULTS: The positive rate of BLCAP protein in primary osteosarcoma was 65.6%,much higher than that in recurrent osteosarcoma, which was 25.0%. CONCLUSION: It may be helpful for evaluating the prognosis of osteosarcoma to study the relationship between expression of BLCAP protein and malignancy of osteosarcoma.

Bone Neoplasms↗
PubMed2003

[Associated genes for dementia of the Alzheimer type].

Dementia of the Alzheimer type (AD) is the leading cause of dementias for the elders. It is a progressively neurodegenerative disorder characterized by global cognitive decline. While most of the rare early-onset AD can be explained by mutations in APP gene and presenilin genes,the genetic etiology of the more common late-onset AD is only partly explained by the APOE-epsilon4 genotype. But the APOE-epsilon4 allele is neither necessary nor sufficient to cause disease and it can only account for less than one-half of the genetic variance of AD. Thus, more genes involved in AD are our special attention.

English Abstract↗
PubMed2003

Development of a newborn screening laboratory quality assurance system in Shandong, China.

Shandong is a large province in northeastern China with a population of over 80 million. There are over 800,000 births annually with newborn screening testing currently being performed in 15 laboratories in city maternity and child health care hospitals. Since 1996, the number of newborns screened has steadily increased until the number screened annually now exceeds 600,000 (over 70%). During the period from 1996--2000, there were 97 cases of classical PKU confirmed and 399 cases of congenital hypothyroidism giving incidences of 1:11,644 and 1:2,831 respectively. The large number of newborns screened and the relatively large number of screening laboratories presents a quality control challenge since ideally each newborn should receive identical newborn screening services and the laboratories should be of equal abilities. With assistance from the US Centers for Disease Control (CDC), a provincial laboratory quality control program has been established and provides oversight for a newborn screening system from blood collection through treatment of patients. The goal is to ensure that patients with the disorders of interest can be identified from within the normal newborn population with an acceptable minimum number of false positives while attempting to eliminate false negatives. External proficiency testing materials are provided quarterly by the CDC, repackaged by the Center for Newborn Screening Quality Control of Shandong (CNQCS), and distributed to the testing laboratories. Analytical results are reported within a specified period of time and then compared to CDC reported results. Laboratories unable to analyze the samples correctly are provided technical assistance. Additionally, the CNQCS oversees and provides educational assistance in training phlebotomists and other health workers associated with newborn screening. Brochures, posters, videotapes and parent support groups are also developed as a function of the CNQCS. Ultimately, control materials will be prepared for distribution with linkages to CDC for international comparability.

Centers for Disease Control and Prevention, U.S.↗
PubMed2002

Physical and functional interaction between receptor-like protein tyrosine phosphatase PCP-2 and beta-catenin.

We have previously identified a human receptor protein tyrosine phosphatase of the MAM domain family, termed PCP-2, in human pancreatic adenocarcinoma cells and found that this protein was colocalized with beta-catenin and E-cadherin at cell junctions [Wang, H.-Y., et al. (1996) Oncogene 12, 2555-2562]. Its intracellular part consists of two tandem phosphatase domains and a relatively large juxtamembrane region that is homologous to the conserved intracellular domain of cadherins, suggesting a role in the regulation of cell adhesion. This study reports that PCP-2 was endogenously expressed at the cell surface and upregulated with increased cell density. An in vivo binding assay revealed that PCP-2 could directly interact with beta-catenin through a region in the juxtamembrane domain. Tyrosine phosphorylation of beta-catenin by EGF or active SrcY527F did not disrupt the formation of the PCP-2-beta-catenin complex, while PCP-2 in this complex could cause a significant reduction in the phosphorylation level in beta-catenin. Finally, we showed that PCP-2 was a negative regulator for cell migration. In conclusion, interaction of PCP-2 with its substrate beta-catenin is involved in the process of cell-cell contact.

Animals↗
PubMed2002

Induction of specific CTL by MAGE-3/CEA peptide-pulsed dendritic cells from HLA-A2/A24(+) gastrointestinal cancer patients.

PURPOSE: In this study, we aimed to investigate whether MAGE3/CEA peptide-pulsed dendritic cells could induce specific cytotoxic T lymphocytes (CTL). METHODS: In this pilot study, we selected 25 patients expressing MAGE-3-HLA-A2/A24 or CEA-HLA-A24. Patients' dendritic cells (DCs) were expanded in vitro in the presence of recombined-human granular macrophage colony stimulating factor (rhGM-CSF) and recombined-human interleukin 4 (rhIL-4), pulsed with MAGE-3/CEA (HLA-A2/A24) peptide. The cytolytic cells' activity, induced by peptide-pulsed DCs and unpurified T cells as effector cells, and with Mel526, 803, Raji, and K562 as target cells, were measured using LDH-releasing assay. RESULTS: DCs were obtained by in vitro expansion in all cases although DC harvest rates varied among different patients (7.1+/-3.2%). Compared with T-IL-2 (IL-2-induced T cells), T-DC-P - which resulted from T-IL-2 co-cultured with DCs pulsed by MAGE3 or CEA peptides - exhibited an increase in cytolytic activity against Mel526 (expressing MAGE-3-HLA-A2) and 803 (expressing CEA-HLA-A24) cell lines by about 25-30% ( P<0.01). In contrast, there was no significant difference between the activity against Raji and K562 cells, which are negative for both peptides. CONCLUSIONS: This study showed that combined usage of rhGM-CSF and rhIL-4 in vitro could expand DCs, and that the DCs pulsed with specific peptides could induce MAGE- and CEA-specific CTL responses. The DC-based vaccine may provide an important method for the immunological treatment of gastrointestinal cancers.

Adult↗
PubMed2002

A novel gene organization: intronic snoRNA gene clusters from Oryza sativa.

Based on the analysis of structural features and conserved elements, 27 novel snoRNA genes have been identified from rice. All of them belong to the C/D box-containing snoRNA family except for one that belongs to the H/ACA box type. The newly found genes fall into six clusters that comprise at least three snoRNA genes, and in one case as many as nine genes. Interestingly, four of the six clusters are located within the largest intron of a protein coding gene. The majority of intronic snoRNA gene clusters are simply formed by multiple copies of the same species of snoRNA gene that possess the identical functional elements. This implies a possible mechanism of duplication for the origin of repeating snoRNA coding regions in one intron. However, a few intronic snoRNA gene clusters consisting of different snoRNAs species were also observed. Polycistronic precursors from two independently transcribed clusters were demonstrated by RT-PCR and individual snoRNAs processed from the polycistronic precursors were positively determined by reverse transcription assay. Analyses of the intergenic spacers in the clusters showed that, in addition to a very high AT content, the processing signals in rice snoRNA polycistronic transcripts might be different from those of yeast. Our results demonstrate that, in both plants and mammals, numerous snoRNAs can be produced simultaneously from an mRNA precursor of a host gene despite the different arrangements. The intronic snoRNA gene cluster is a novel gene organization, which is so far unique to plants. The conservation of intronic snoRNA gene clusters in plants was further demonstrated by the study of a similar snoRNA gene organization in the first intron of a Hsp70 gene from wild rice and Zizania caduciflora.

Base Sequence↗
PubMed2002

Chronic kidney isograft and allograft rejection.

In this study antigen-independent factor in the pathogenesis of chronic rejection of organ transplants was examined. Kidney isografts and allografts were transplanted orthotopically into bilaterally nephroectomized rat recipients and studied functionally, morphologically and immunohistologically, at serial intervals up to 52 weeks after transplantation. Allograft recipients developed progressive proteinuria after 12 weeks, with gradual renal failure ultimately leading to death. At the same time, morphological changes, including progressive arteriosclerosis and glomerulosclerosis, tubular atrophy and interstitial fibrosis, developed. Immunohistologically, macrophages infiltrated glomeruli during this period and cytokines became unregulated. Our results showed that antigen-independent functional and morphological changes occurred in long-term kidney isografts and mimicked those appearing much earlier in allografts that reject chronically. Initial injury and extent of functioning renal mass is suggested to be important factor for such late changes.

Animals↗
PubMed2002

Gene expressions in Jurkat cells poisoned by a sulphur mustard vesicant and the induction of apoptosis.

1. The sulphur mustard vesicant 2-chloroethylethyl sulphide (CEES) induced apoptosis in Jurkat cells. 2. Akt (PKB), a pivotal protein kinase which can block apoptosis and promotes cell survival, was identified to be chiefly down-regulated in a dose-dependent manner following CEES treatment. Functional analysis showed that the attendant Akt activity was simultaneously reduced. 3. PDK1, an upstream effector of Akt, was also down-regulated following CEES exposure, but two other upstream effectors of Akt, PI3-K and PDK2, remained unchanged. 4. The phosphorylation of Akt at Ser(473) and Thr(308) was significantly decreased following CEES treatment, reflecting the suppressed kinase activity of both PDK1 and PDK2. 5. Concurrently, the anti-apoptotic genes, Bcl family, were down-regulated, in sharp contrast to the striking up-regulation of some death executioner genes, caspase 3, 6, and 8. 6. Based on these findings, a model of CEES-induced apoptosis was established. These results suggest that CEES attacked the Akt pathway, directly or indirectly, by inhibiting Akt transcription, translation, and post-translation modification. 7. Taken together, upon exposure to CEES, apoptosis was induced in Jurkat cells via the down-regulation of the survival factors that normally prevent the activation of the death executioner genes, the caspases.

3-Phosphoinositide-Dependent Protein Kinases↗