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Biomedical subjects

J Shen

Publications and source records attributed to J Shen.

At least 181 records · Page 10Linked to original sources
PubMed2000

Seeds induced to germinate rapidly by mentally projected 'qi energy' are apparently genetically altered.

Mentally controlled qi energy can induce crop seeds to sprout and root for several cm within about 20 min. The RAPD method was used to compare treated groups of wheat and pea seeds and their controls using 11 selected primers. Seven primers amplified polymorphisms in wheat seeds and 5 in pea seeds. It was thought preliminarily that qi energy changed the structure of a germination-correlated gene site speeding up expression and advancing it in time.

Germination↗
PubMed2000

Prognostic significance of nuclear accumulation of c-myc and mdm2 proteins in synovial sarcoma of the extremities.

We retrospectively analysed a group of primary tumours from 32 patients with synovial sarcomas of the extremities by using immunohistochemistry on paraffin-embedded tissue samples in order to investigate the prognostic significance of the nuclear accumulation of c-myc and mdm2 proteins. Nuclear positive immunostaining for c-myc or mdm2 proteins were revealed in 9/32 cases (28%) and in 6/30 cases (20%), respectively. Since c-myc protein appears to be a key factor for keeping cells in an active proliferative stage, we also analysed the growth compartment of each tumour by using the MIB1 monoclonal antibody, specific for Ki-67 antigen. A high MIB1 index was found in 8/31 cases (26%) but was not associated either with c-myc or mdm2 nuclear positivity. Analysis of clinical outcome was performed in a subgroup of 27 patients with a minimum follow-up of 24 months. Among the clinicopathologic parameters and the biological markers, only the nuclear accumulation of c-myc was significantly associated with a higher relapse rate (p = 0.03). Accordingly, survival analysis confirmed a trend toward a poor event-free survival rate and a worse outcome in c-myc-positive cases (p = 0.12). These data demonstrate that assessment of c-myc nuclear accumulation can be useful to identify high-risk subsets of patients with synovial sarcoma of the extremities.

Adolescent↗
PubMed2000

UVA and UVB wavebands modulate expression of fasL in mouse skin epidermis.

In our previous report, we observed different cytokine modulation in mouse epidermis by the UVA and UVB wavebands. In the present investigations, the effects of irradiation with UVA and UVB on the Fas(CD95)/FasL system have been studied because apoptosis mediated by the interaction between Fas and FasL has been suggested recently to be associated with UVB-induced immunosuppression in mouse skin. Our results show that UVA irradiation following UVB irradiation has the ability to reduce the up-regulation of FasL expression in mouse skin resulting from the UVB irradiation.

Animals↗
PubMed2000

Presenilin-1 regulates neuronal differentiation during neurogenesis.

Mutations in Presenilin-1 (PS1) are a major cause of familial Alzheimer's disease. Our previous studies showed that PS1 is required for murine neural development. Here we report that lack of PS1 leads to premature differentiation of neural progenitor cells, indicating a role for PS1 in a cell fate decision between postmitotic neurons and neural progenitor cells. Neural proliferation and apoptotic cell death during neurogenesis are unaltered in PS1(-/-) mice, suggesting that the reduction in the neural progenitor cells observed in the PS1(-/-) brain is due to premature differentiation of progenitor cells, rather than to increased apoptotic cell death or decreased cell proliferation. In addition, the premature neuronal differentiation in the PS1(-/-) brain is associated with aberrant neuronal migration and disorganization of the laminar architecture of the developing cerebral hemisphere. In the ventricular zone of PS1(-/-) mice, expression of the Notch1 downstream effector gene Hes5 is reduced and expression of the Notch1 ligand Dll1 is elevated, whereas expression of Notch1 is unchanged. The level of Dll1 transcripts is also increased in the presomitic mesoderm of PS1(-/-) embryos, while the level of Notch1 transcripts is unchanged, in contrast to a previous report (Wong et al., 1997, Nature 387, 288-292). These results provide direct evidence that PS1 controls neuronal differentiation in association with the downregulation of Notch signalling during neurogenesis.

Animals↗
PubMed2000

The alteration of mitochondria is an early event of arsenic trioxide induced apoptosis in esophageal carcinoma cells.

It is accepted that inorganic arsenic trioxide is an inducer of apoptosis for many types of cancer. Our previous studies have demonstrated that arsenic trioxide induces apoptosis of esophageal carcinoma cells. Administration of arsenic trioxide results in the inhibition of growth and survival of tumor cells. Esophageal carcinoma cells treated with arsenic trioxide for 3 days demonstrated a typical morphological appearance of apoptosis. To further examine molecular mechanism of arsenic trioxide induced apoptosis of esophageal carcinoma cells, we have investigated the early changes of the apoptotic cell induced by arsenic trioxide. Our results indicated that arsenic trioxide induced apoptosis of esophageal carcinoma cells occurs as early as 2 h after treatment. Annexin-v staining has further proved that the phosphatidylserine is exposed at 2 h. The early morphological change of arsenic trioxide treated cells was in the mitochondria. Arsenic trioxide treated cells displayed aggregated mitochondria. It induces accumulation of high electron-density amorphous substances, swollen and disruption of mitochondria in oesophageal carcinoma cells after 2 h treatment. The alteration of mitochondria induced by arsenic trioxide seems to occur before the condensation of chromatin. Thus, our data demonstrated that the primary target of arsenic trioxide induced apoptosis of esophageal carcinoma cells may be the mitochondria. It is possible that arsenic trioxide is a mitochondriotoxic agent.

Antineoplastic Agents↗
PubMed2000

Heterogeneous populations of ES cells in the generation of a floxed Presenilin-1 allele.

Generation of a floxed Presenilin-1 (PS1) allele involved two recombination events in the embryonic stem (ES) cells. First, a targeting vector containing a loxP site in intron 1 and a floxed CMV-HYG/TK double selection cassette in intron 3 was integrated into the PS1 locus by homologous recombination. The use of a negative selection cassette, PGK-DTA, dramatically increased the recombination efficiency within the targeted locus (75-fold). Second, an expression vector encoding Cre recombinase was introduced to excise the floxed CMV-HYG/TK cassette via site-specific recombination. However, all five ES cell clones testing positive for the proper removal of the CMV-HYG/TK cassette also contained a proportion of ES cells in which recombination had occurred between the distal loxP sites in introns 1 and 3, resulting in excision of the entire floxed region. It is therefore critical to screen for possible recombination events involving all 3 loxP sites, in order to identify ES cells clones bearing high proportions of the desired ES cells. genesis 26:5-8, 2000.

Alleles↗
PubMed2000

Molecular cloning of a novel retinoic acid-responsive gene, HA1R-62, which is also up-regulated in Hoxa-1-overexpressing cells.

Using a PCR-based cDNA subtractive hybridization method (L. Diatchenko et al., Proc. Natl. Acad. Sci. USA, 93: 6025-6030, 1996), we cloned a cDNA fragment of a novel gene that is highly expressed in F9-10; F9-10 is an F9 teratocarcinoma stem cell line that expresses high levels of exogenous Hoxa-1 mRNA and protein in comparison to F9 wild-type stem cells, which do not express endogenous Hoxa-1 mRNA in the absence of retinoic acid (RA). Rapid amplification of cDNA ends was used to clone the full-length cDNA of this gene, designated HA1R-62 (Hoxa1 regulated-62). We have shown that HA1R-62 is also a RA-responsive gene and that it is expressed (mRNA size, approximately 4.3 kb) in adult mouse thymus, lung, kidney, and ovary as well as in 12.5-day mouse embryos. DNA sequence analysis and in vitro translation experiments have shown that HA1R-62 encodes a protein with a molecular mass of approximately 26 kDa. Elucidation of the function of the HA1R-62 gene product will provide new insights into the functions of RA and homeobox genes.

Amino Acid Sequence↗
PubMed2000

New potential photodynamic therapeutic anti-cancer agents: synthesis and characterization of demethoxy amino-substituted hypocrellins.

A novel method was used to obtain demethoxy amino-substituted hypocrellin derivatives. The reaction condition was mild and amino substitution occurred at position 2 or 11 of hypocrellins with high yield. The photophysical and photochemical properties of the amino-substituted hypocrellins derivatives were investigated, and their significantly enhanced red absorptivities and strong active oxygen-generating functions qualified them as promising photodynamic therapeutic anti-cancer agents.

Antineoplastic Agents↗
PubMed2000

[Clinicopathological studies on bone marrow involvement of non-Hodgkin's lymphoma].

OBJECTIVE: To investigate the relationship between pathomorphological features and clinical manifestations of non-Hodgkin's lymphoma (NHL) with bone marrow involvement (BMI). METHODS: Plastic-embedded section of bone marrow biopsy was stained with H-Giemsa-E. Immunotyping of NHL was performed immunohistochemically. RESULTS: A total of 70 patients with NHLBMI(male: 52, female: 18; median age: 49 years) was studied. There were 20 patients with T cell-lymphoma and 50 patients with B cell-lymphoma. The extent of bone marrow involvement was minimal in 15 cases, moderate in 16 cases and severe in 39 cases. Bone marrow involvement was of interstitial type in 23 cases, nodular type in 7 cases, and mixed type in 18 cases and diffuse type in 22 cases. The frequency of splenomegaly in nodular type NHLBMI was significantly higher than that in any other type. Nodular type NHLBMI occurred mainly in B cell-lymphoma. Lymphoma cell leukemia (LCL) developed in 14 of 39 (35.9%) cases of NHL with severe bone marrow involvement which was significantly more frequent than that in NHL with mild and moderate bone marrow involvement. CONCLUSION: Difference in the extent and pattern of bone marrow involvement in NHL is related to clinical manifestations. Bone marrow biopsy helps evaluate response to treatment.

Adolescent↗
PubMed2000

Mitochondrial gene variation in type 2 diabetes mellitus: detection of a novel mutation associated with maternally inherited diabetes in a Chinese family.

OBJECTIVE: To explore the relationship between type 2 diabetes mellitus and the mutation(s) in mitochondrial DNA. METHODS: According to the previous literature, the fragment of mitochondrial DNA from nucleotide 3153 to 3551, which had shown high frequency of point mutation, was scanned with the technique of polymerase chain reaction--single strand conformation polymorphism (PCR-SSCP) in Chinese normal control, type 2 diabetic population, and 12 families suffered from maternally inherited type 2 diabetes mellitus. Direct sequencing was applied to detect the fragments with abnormal conformation. RESULTS: No special band was found in SSCP electrophoreses in Chinese normal control, and only one subject (No. 81) of diabetic population indicated the abnormality in SSCP study, which was affirmed to be a silent point mutation of T to C at nucleotide 3336 inducing no change in amino acid (ATT-->ATC, Ile). Pedigree 25,001 was the only family that exhibited strongly different SSCP characteristic from the other 11 ones, which was confirmed to be caused by a single point mutation mt3285T-->C/T in the coding region of tRNA(Leu(UUR)) gene by the technique of direct sequencing. CONCLUSIONS: The variation within mt DNA 3153-3551 is not the major cause of type 2 diabetes in Chinese population suffered from this disease in this study. The point mutation T-->C/T at the mitochondrial nucleotide 3285, which was found in pedigree 25,001, is located in the highly conservative region of tRNA(Leu(UUR)) gene. It is strongly suggested that this mutation cause the conversion in the 3-dimentional structure of tRNA(Leu(UUR)), which might disturb the normal translation and lead to the impairment in mitochondrial oxidative phosphorylation characterized by the defects of the polypeptides involved in the respiratory chain. Thus, insulin secretion deficiency and insulin resistance might occur.

Adult↗
PubMed2000

P16 overexpression in pituitary adenomas studied by immunohistochemistry and in situ hybridization.

OBJECTIVES: To examine the expression of p16 gene and the clinicopathological characteristics of 31 pituitary adenomas. To investigate the relationship between p16 expression and cell proliferative activity by analyzing the expression of proliferating cell nuclear antigens (PCNA). METHODS: Immunohistochemistry and in situ hybridization were performed on freshly-prepared paraffin-embedded specimens of 31 pituitary adenomas. RESULTS: Varying degrees of overexpression of the p16 gene was found in the tumors specimens. A higher proportion of p16 positive tumor cells was associated with bigger size, more frequent invasion and higher recurrence of the tumors. The expression of p16 was found to be significantly associated with the degree of PCNA expression. CONCLUSION: Though inactivation of the p16 gene is known in wide range of tumors, our study suggested that p16 overexpression might play a role in the development and progression of pituitary adenomas.

Adenoma↗
PubMed2000

The effects of glucose, insulin and oxidized low density lipoprotein on apoptosis in vascular endothelial cells.

OBJECTIVE: To study the effects of high concentrations of glucose, insulin and oxidized low density lipoprotein (ox-LDL) on apoptosis in cultured bovine aortic endothelial cells (ECs). METHODS: For qualitative determination of EC apoptosis, acridine orange (AO)/ethidium bromide (EB) staining and DNA agarose gels electrophoresis were used. Cellular DNA fragmentation ELISA measured apoptosis by quantitating the fragmentation of 5-bromo-2'-deoxyuridine-labeled DNA. RESULTS: High concentrations of glucose (20 mmol/L, 40 mmol/L), insulin (3000 microU/ml) and ox-LDL (50 micrograms/ml, 100 micrograms/ml) induced concentration- and time-dependent apoptosis in ECs. They had a synergetic effect on EC apoptosis. The combined effect of high concentration of glucose, insulin and ox-LDL was greater than any two of them; the effect of two was greater than one alone. Low concentration of insulin (30 microU/ml) decreased apoptosis in ECs induced by high concentrations of glucose (40 mmol/L), but no similar effect occurred with ox-LDL (100 micrograms/ml). CONCLUSION: High ambient glucose, insulin and ox-LDL can induce excessive apoptosis in cultured ECs, and low ambient insulin can prevent EC apoptosis. Excessive EC apoptosis induced by the separate or synergetic effect of hyperglycemia, hyperinsulinemia and hyperlipidemia may be one of the reasons for loss of endothelial integrity, dysfunction of the vascular endothelium and increased plasma membrane permeability, which are all involved in the development of diabetic macrovascular complications.

Animals↗
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

[Endoscopy-assisted neurosurgery for intracranial operation].

OBJECTIVE: To investigate the value of endoscope-assisted neurosurgery for intracranial operation. METHODS: 37 patients with intracranial lesions including tumors, aneurysms, cysts, hematomas, hydrocephalus and nerve-vessel compression syndrome were treated with this method. Their results were compared to those of microsurgery and macrosurgery. The items analyzed included exposure and protection of brain tissue and cranial nerves, views of operation field, length of procedure etc. RESULTS: 15 patients with tumors, showed a high rate of complete removal but less complications. The 6th nerves of CPA tumors operation were preserved. Six cases of nerve-vessel compression syndrome showed excellent therapeutic effects. In 8 cases of intraventricle lesions, using endoscope easily found tumor location and the cause of hydrocephalus. As to saccular diseases, endoscope was used to deal with the major location. In 4 cases of hematomas, less blot remained and the procedure shortened. Moreover the operation field was more clear and adequate on the expenses of no more complexity of the procedure. CONCLUSIONS: Endoscope-assisted microsurgery is helpful in intracranial operation. It might become a standard neuro-operation in near future.

Adolescent↗
PubMed2000

[The susceptible alleles on HLA-DRB 1 of type I diabetes in children in Harbin].

OBJECTIVE: To evaluate association between type I diabetes in children and HLA-DRB1 alleles in Harbin. METHODS: Case-control method was employed, and the PCR-SSP technique was used to identify HLA-DRB1 alleles. RESULTS: The frequencies of DRB1 * 0301 and DR3/4 heterozygosity were significantly higher but the frequency of DR2 was significantly lower in cases than that in controls. In DR4 subtypes, the frequency of DRB1 * 0405 was higher and the frequency of DRB1 * 0406 was lower in cases than that in the controls. The difference between cases and controls in DRB1 * 0901 was not significant. CONCLUSION: DRB1 * 0301 allele and DR3/4 heterozygosity were the important susceptibility and heterozygosity genes while DR2 was the most important protective gene in Harbin. The DR4 possessed double-tendency. DRB1 * 0405 conferred susceptibility and DRB1 * 0406 conferred little protection. The susceptibility conferred by DRB1 * 0901 was not certain in type I diabetes in childhood in China. This study provided useful genetic data on the study of etiology of type I diabetes mellitus.

Alleles↗
PubMed2000

[Morphological changes of mitochondria in apoptosis of esophageal carcinoma cells induced by As(2)O(3)].

OBJECTIVE: In order to make clear how As(2)O(3) targets the cells of esophageal carcinoma, the morphology of mitochondria and expression of bcl-2/bax were selected to study the SHEEC1 cell line during early apoptosis. METHODS: The esophageal carcinoma cell line SHEEC1 was treated by As(2)O(3) with concentrations of 1, 2 and 3 micromol/L for the periods of 2, 4, 6, 12 and 24 h. Annexin-V-Fluorescein and DNA histogram were used to detect the early apoptotic cells by flow cytometry. The morphologic changes of the apoptotic cells were examined by means of light and electron microscopy. Changes in mitochondria of living cells were detected with Rhodamin 123 fluorescent probe by fluorescent microscopy. The expression of bcl-2 and bax in floating cells were determined by immunohistochemical procedures. RESULTS: Typical apoptotic morphological changes were found in SHEEC1 at 24 h after As(2)O(3) treatment. Cells in the early stage of apoptosis were detected by Annexin-V labeled at 4 h. The ultrastructural alterations of mitochondria were found as following: within 4 h after administrating As(2)O(3), mitochondrial hyperplasia with small electron-dense materials in its matrix was the earliest manifestation of cell injury. At 6 h progressive mitochondrial swelling lead to balloon-like appearance and its outer membrane disrupted at 12 h. In all groups, down regulated expression of bcl-2 and over expression of bax were always found in damaged cells. CONCLUSION: In the SHEEC1 cell line morphological changes of mitochondria are the early events in apoptosis induced by As(2)O(3) and apoptosis is closely related to over expression of bax and down-regulating expression of bcl-2. It is possible that As(2)O(3) is a mitochondriotoxic anticancer agent for esophageal carcinoma.

Antineoplastic Agents↗
PubMed2000

[Study on the antitumor activity of CBMC activated by IL-12 alone or in combination with IL-2].

OBJECTIVE: To investigate the efficacy of cord blood mononuclear cells (CBMC) activated by interleukin-12 (IL-12) alone or in combination with interleukin-2 (IL-2) in tumor cells. METHODS: The cytotoxicity of CBMC and peripheral blood mononuclear cells (PBMC) activated by IL-12 and/or IL-2 was measured with (3)H-TdR release assay, and the morphological change of K562 cells incubated with activated CBMC was observed. RESULTS: (1) CBMC activated by 10 IU/ml IL-12 produced significant cytotoxic activities which were (27.23 +/- 4.92)% and (29.12 +/- 3.46)% against K562 and Raji cells, respectively; moreover, 10 IU/ml IL-12 could be synergized with the same dose of IL-2 in enhancing the cytotoxicities which were (47.60 +/- 4.60)% and (38.69 +/- 4.86)% against the two target cells, respectively. (2) Short-term incubation with IL-12 activated CBMC increased the cytotoxicity to K562 cells, and long-term incubation increased the cytotoxicity to Raji cells. (3) No NK lytic activity of CBMC could be detected before cytokines stimulation. After stimulated by 10 IU/ml IL-12, NK lytic activity of CBMC was similar to that of PBMC. (4) K562 cells demonstrated obvious apoptosis after cultured with activated CBMC. CONCLUSION: CBMC activated by IL-12 had evident antitumor activity, which was further increased when IL-12 in combination with IL-2. These results showed the potential value to improve the graft-versus-leukemia (GVL) response after cord blood progenitor cell transplantation.

Adult↗