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Biomedical subjects

D Wang

Publications and source records attributed to D Wang.

At least 397 records · Page 22Linked to original sources
PubMed2000

[A preliminary meta-analysis of 36 studies on impairment of intelligence development induced by iodine deficiency].

OBJECTIVES: Since 1980 s', numerous studies on intelligence quotient (IQ) have documented, in the areas prevalent with severe, moderate and even mild iodine deficiency, which is a risk factor for retardation in mental development there. It was purposed for this paper to quantify the relationship between iodine deficiency and mental development in children and to explore the etiological role of iodine deficiency in mental retardation and the protective effects on children's intelligence of iodine supplementation. METHODS: A total of 59 independent investigations published during 1980 and 1998 were selected for meta-analysis, including 20 studies on intelligence determined by Raven's Test and 39 by China Benit Scale. RESULTS: Homogeneity test showed that there was no significant difference in baseline features between two groups (P > 0.05). The hypothesis testing showed that the homogeneity of each study group was obviously statistically significant (P > 0.05). The results demonstrated that IQ in children at risk for iodine deficiency showed a marked drop by 8.94 points with Raven's Test and by 10.80 points with China Binet Scale, respectively, with an average drop of 10 points. Substantial evidence now available has showed that mental retardation can be prevented by effective correction of iodine deficiency through iodine supplement either iodized salt or iodized oil, which is confirmed by an obvious increase in 11.5 points of IQ in average, and in 11.85 by Raven's Test and 11.64 by China Binet Scale, respectively. CONCLUSIONS: Iodine nutrition plays an important and positive role in brain development. Iodine deficiency leads to loss of 10 points of IQ and 11.5 points can be gained for children in the iodine deficiency areas after significant iodine supplement.

Adolescent↗
PubMed2000

[The regulation effects of growth factors on the procollagen gene expressions of human mandibular condylar cartilage cells].

OBJECTIVE: At the early stage of osteoarthrosis (OA) and joint damage, the cartilage cells proliferation increases dramatically, but this repair process is finally replaced by the progressive destruction of the cartilage. The reason, in accordance to the latest research, is the abnormal phenotype of the involved cartilage cell. This result suggests that the regulation of cartilage cell phenotype may be an effective way in the treatment of OA and other cartilage destructive diseases. In this study, the effects of transforming growth factor-beta(TGF-beta), insulin-like growth factor-I (IGF-I) and basic fibroblast growth factor (bFGF) on collagen expression of human mandibular condylar cartilage cells was investigated. METHODS: Chondrocytes were isolated from human fetus by enzymatic method. The second passage of the cells was used in this study. They were cultured in DMEM medium supplemented with 20% newborn calf serum (NCS). After the cells reached confluence, the medium was replaced by DMEM containing 0.4% NCS. Then the cells were exposed to different growth factors including IGF-I (10 ng/ml), TGF-beta (5 ng/ml) and bFGF (50 ng/ml). The steady state mRNA levels of different samples were examined by slot-blot hybridization. The results were analysed by Student t test. RESULTS: IGF-I had the least effects on the mRNA levels of three kinds of procollagen (type I, type II and type III). On the other hand, bFGF and TGF-beta could inhibit the expression of type II collagen by 0.352 and 0.685 times comparing with the control groups separately. TGF-beta increased type I collagen expression. Besides, bFGF and TGF-beta also increased the value of type I collagen/type II collagen. None of the three kinds of growth factors had obvious effects on the expression of type III collagen. CONCLUSION: IGF-I can maintain the chondrocyte differentiated phenotype, while TGF-beta and bFGF have inhibitory effects.

Cells, Cultured↗
PubMed2000

[Ultrastructure of the lymph capillaries in human dental pulp].

OBJECTIVE: The purpose of this article is to observe the ultrastructures of the lymph capillaries in the human dental pulps. METHODS: Investigations have been performed on dental pulps from 8 human permanent teeth, including 4 mandibular first premolars and 4 maxillary first premolars, which were extracted for orthodontic reason. As soon as possible, we cleaved the teeth longitudinally and immersed in the fixative solution at 4 degrees C for 1 hour, then kindly removed the pulps and immersed in the same fixative solution for 3 hours, then routinely postfixed, dehydrated, embedded, and prepared the ultrathin sections (50-70 nm) without semithin section localization. The lymph vessels were distinguished from blood vessels on ultrathin sections by their morphological features. RESULTS: We have observed three fundamental kinds of intercellular junctions, overlapping(51%), end to end(36.1%), and interdigistating (10.6%). A few complex junctions also could be seen, but we failed to find the open junction. The Weibel-Palade bodies were occasionally present in the lymphatic vessels endothelial cells of young dental pulps. And we even found the lipofuscins in the cytoplasm of the endothelium. Some inclusion bodies, such as paracrystalline inclusions and myeloid bodies, also could be seen. There were many micropinocytotic vesicles in the cytoplasm of the lymphatic endothelium, the diameter of the most vesicles was about 50-80 nm, some was about 100-500 nm. Some vesicles appeared to lie free within the cytoplasm, and some were seen to touch or open onto the luminal or abluminal surfaces of the endothelia, which suggested that many vesicles were not simple discrete units but rather from parts of chains that reached either luminal or abluminal surfaces. It was reported that micropinocytotic vesicles, open junctions and intraparietal channels provided fluid transport. CONCLUSION: Dental pulp is a special organ, and the lymph capillaries in it have their own ultrastructural features.

Adolescent↗
PubMed2000

[Gene cloning and expression of prolyl endopeptidase from Aeromonas punctata].

Prolyl endopeptidase gene was cloned from Aeromonas punctata subsp. Punctata(ST-78-3-3) using activity screening method and the 3.3 kb DNA fragment containing PEP gene was sequenced. DNA sequence from 20-2092 bp was ORF region coding 690 amino acids of prolyl endopeptidase. It was a new PEP gene through gene search. The genetic engineered E. coli BL21/pGEM-PEP overexpressing recombinant Aeromonas punctata prolyl endopeptidase(apPEP) was constructed. Cultured in YH medium, the expressed apPEP was about 30% of total cellular protein, the activity was 112 times more than that of wild strain. Expressed apPEP was mainly soluble intracellular protein, about 5% of apPEP was secreted to medium. Non-reduced SDS-PAGE analysis showed it's monomer with molecular weight about 76 kD, which corresponded with prediction by gene sequence. Recombinant apPEP was purified after tube culture, the purity reached 90% and specific activity was 67 U/mg.

Aeromonas↗
PubMed2000

[Use of Hopkins rod-lens coupled with grasping forceps sheaths for extraction of tracheobronchial foreign bodies].

OBJECTIVE: To study the clinical application of Hopkins rod-lens coupled with gasping forceps sheaths in the extraction of tracheobronchial foreign bodies. METHODS: Sixty-two patients with tracheobronchial foreign bodies were operated on with Hopkins rod-lens coupled with grasping forceps sheaths under direct telescopic view or TV watching. High frequency jet ventilation was used and BPs ECGs SaO2 were monitored in all cases. RESULTS: Sixty-two patients were all successfully operated on. The extraction was primarily successful in 90% of the cases; and secondarily successful in 7% of the cases. No death and serious complication occurred. CONCLUSION: Compared with conventional bronchoscopic foreign body extraction, this new instrument and technique make it possible for the operator to clamp and extract foreign body under direct telescopic view or TV watching. It has increased the accuracy and safety of bronchoscopic extraction of tracheobronchial foreign bodies.

Adolescent↗
PubMed2000

[Areas of brain involved in immunoregulation].

OBJECTIVE: To study the location of brain areas involved in immunoregulation. METHODS: Immunohistochemistry and immunofluorescence were used to detect the different distribution of cytokines immunopositive cells in the brain of rats immunized via both intraperitoneal and subcutaneous injections. RESULTS: The cytokines immunopositive cells were distributed in the supraoptic (SO) and paraventricular (PV) nuclei of the hypothalamus, the anterior hypothalamic (AH) nucleus, arcuate and median eminence, the lateral hypothalamic nucleus (LH) and the amygdaloid nuclear complex while only the appearance of the cytokines immunopositive cells in LH and amygdaloid nuclear complex in hypothalamus was related with immunization status of the animals. Double-labelling results showed that the cytokines immunopositive cells were neurons. CONCLUSIONS: We have observed that neurons of the LH and amygdaloid nuclear complex in hypothalamus as a main source of the neuroimmunoregulation played a key role in neuroimmunoregulation and they participated in the neuroimmunoregulation at an early stage of the immune response.

Amygdala↗
PubMed2000

[Effect of antisense oligonucleotides on the TXA2 production of macrophages stimulated by endotoxin].

OBJECTIVE: To select efficient fragments which can inhibit gene expression of thromboxane synthase and production of thromboxane A2. METHODS: Rat peritoneal macrophages were incubated with oligonucleotides (ODNs) and endotoxin (which was composed of lipopolysaccharide) for 24 hours. The TXB2 content was determined by RIA. Thromboxane synthase (TXS) mRNA expression was measured with RNA dot hybridization. RESULTS: The concentration of TXB2 in ODN I group was (69.7 +/- 10.9) pg/microgram cell protein, lower than those in control group (100.6 +/- 28.6) pg/microgram cell protein (P < 0.05, n = 4), TXS mRNA expression level in ODN I group was decreased as compared to those in control group. Neither in ODN II nor in ODN III group were there any changes on TXB2 contents and TXS mRNA levels. CONCLUSIONS: ODN I can inhibit the production of TXA2 and the gene expression of thromboxane synthase from macrophages stimulated by endotoxin.

Animals↗
PubMed2000

[Synthesis and spectroscopic characterization of a new blue light-emitting material complexes and study of its photoluminescence and electroluminescence characterization].

The Zn-complexe emitting blue light was synthesised and characterized spectroscopically by elemental analysis, UV, EX, EM, IR. Photoluminescence and electroluminescence characterization of the light-emitting diodes using Zn-complexe as the emissive layer was studied, it could emit blue light with a peak wavelength at 455 nm and a brightness of about 37.2 cd.m-2.

Chelating Agents↗
PubMed2000

[Determination of artificial synthetic pigment by excitation spectrophotometry].

Solid phase spectrophotometry is a mew, simple, fast and sensitive trace analytical method. In this report, it is presented with a method that the polyamide was used for the absorbance and the excitation spectra was measured directly. The background of the solid phase spectrophotometry was overcome, the sensitivity was increased in a big way. The method is good standard addition recovery and precision, high accuracy. Not only the trace inorganic ion can be analysed by the solid phase method, but also the artificial synthetic pigment, the result was satisfied.

Adsorption↗
PubMed2000

[The TEM investigations of lymphatic vessels in the acute inflamed dental pulps].

OBJECTIVE: The purpose of this study was to investigate the possible ultrastructural modifications of the lymphatic capillaries in the acute inflamed dental pulps. METHODS: The ultrastructural features of the lymphatic vessels endothelial wall in the human normal and acute inflamed dental pulps were investigated by TEM using conventional methods. RESULTS: The lymphatic capillaries in normal dental pulp were characterized by a thin wall with an irregular profile. The endothelial cells were joined one another by specialized junctional complexes, such as end-to-end contacts, overlapping and more complex interdigitation. Opening junctions were never present in these vessels. The cytoplasm of the endothelial cells was rich in micropinocytotic vesicles. In the acute inflamed pulpal tissue, the lymphatic vessels were dilated and the intercellular adjoining structure were less intricate, end-to-end contacts and overlaping were most frequent ones. Opening junctions were frequently detectable. In particular, the micropinocytotic vesicles were almost absent. CONCLUSION: In the acute inflamed pulpal tissue, the modification occurs in the diameter of lymphatic capillaries, intercellular adjoining structures and the amounts of micropinocytotic vesicles, so we thought that a network of lymphatic vessels drained the dental pulp.

English Abstract↗
PubMed1999

Studies of the DXS7 polymorphism at the MAO loci in unipolar depression.

From the fact that DXS7 polymorphism is closely related to monoamine oxidase (MAO) genes and MAO inhibitors are widely used in the treatment of unipolar depression, it is of particular interest to study the relationship between the DXS7 polymorphism and unipolar depression. Thus, this study examined the possible association between DXS7 polymorphism and unipolar depression in 66 cases versus 85 controls from Shanghai. Polymerase chain reaction and amplification fragment length polymorphism techniques were used for genotyping of the DXS7 locus in this study. Four alleles at the DXS7 locus were detected with length generated by polymerase chain reaction amplification ranging from 157 to 167 bp. Comparison of allele frequency in the DXS7 locus showed no difference between unipolar depression cases and normal controls in the total population set. When subclassified by age, a significant difference of allele frequency distribution was observed between early onset (before age 40) and late onset (after age 40) patients. The frequency of the 157-bp allele was decreased, whereas the frequency of the 165 allele was increased in late onset patients (0.3810 for the 157-bp allele and 0.5238 for the 165-bp allele) compared with that of early onset patients (0.6304 for the 157-bp allele and 0. 3261 for the 165-bp allele). There was also a difference of allele frequency between patients and normal controls with age over 40 years. The frequency of 165-bp allele increased significantly in late onset patients (0.5238) compared with that of controls within the same age range (0.3454). Association studies suggested that in the population with age over 40 years, presence of the 165-bp allele of DXS7 locus was significantly associated with unipolar depression (relative risk = 2.08, P < 0.05), whereas in the total population set, this association did not exist. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:598-600, 1999.

Adolescent↗
PubMed1999

SOCS1 deficiency causes a lymphocyte-dependent perinatal lethality.

SOCS1 is an SH2-containing protein that is primarily expressed in thymocytes in a cytokine- and T cell receptor-independent manner. SOCS1 deletion causes perinatal lethality with death by 2-3 weeks. During this period thymic changes include a loss of cellularity and a switch from predominantly CD4+ CD8+ to single positive cells. Peripheral T cells express activation antigens and proliferate to IL-2 in the absence of anti-CD3. In addition, IFNgamma is present in the serum. Reconstitution of the lymphoid lineage of JAK3-deficient mice with SOCS1-deficient stem cells recapitulates the lethality and T cell alterations. Introducing a RAG2 or IFNgamma deficiency eliminates lethality. The results demonstrate that lymphocytes are critical to SOCS1-associated perinatal lethality and implicate SOCS1 in lymphocyte differentiation or regulation.

Age Factors↗
PubMed1999

SOCS3 is essential in the regulation of fetal liver erythropoiesis.

SOCS3 (CIS3/JAB2) is an SH2-containing protein that binds to the activation loop of Janus kinases, inhibiting kinase activity, and thereby suppressing cytokine signaling. During embryonic development, SOCS3 is highly expressed in erythroid lineage cells and is Epo independent. Transgene-mediated expression blocks fetal erythropoiesis, resulting in embryonic lethality. SOCS3 deletion results in an embryonic lethality at 12-16 days associated with marked erythrocytosis. Moreover, the in vitro proliferative capacity of progenitors is greatly increased. SOCS3-deficient fetal liver stem cells can reconstitute hematopoiesis in lethally irradiated adults, indicating that its absence does not disturb bone marrow erythropoiesis. Reconstitution of lymphoid lineages in JAK3-deficient mice also occurs normally. The results demonstrate that SOCS3 is critical in negatively regulating fetal liver hematopoiesis.

Animals↗
PubMed1999

Generation of acetylcholine receptor-specific human T cell lines using heterobifunctional antibody-targeted antigen presentation.

Characterizing AChR-specific T lymphocyte clones is an important step towards the ability to induce antigen-specific tolerance in myasthenia gravis (MG). However, the limited supply of relatively inefficient autologous antigen presenting cells (APCs) makes establishing AChR-specific T lymphocyte lines difficult. In this study we targeted AChR to autologous surface IgM+ (sIgM+) APCs using heterobifunctional antibodies (bi-Ab) consisting of anti-sIgM linked to anti-AChR antibodies. FACScan analysis and whole cell-based radioimmunoassay (RIA) showed binding of bi-Ab/AChR conjugates to sIgM+ APCs. Using antigen targeting, AChR-presentation to a well-characterized AChR-specific T cell clone, and to T cell lines raised de novo from MG thymocytes, was improved. Thus, antigen targeting using bi-Ab improved the efficiency of presentation of the scarce autoantigen AChR, suggesting that this method might allow the use of relatively impure antigen preparations and normally inefficient non-antigen-specific APCs, including those which can be immortalized, to accelerate the characterization of the AChR epitopes recognized by pathogenic T helper lymphocytes.

Animals↗
PubMed1999

Direct projections from the medial preoptic area to spinally-projecting neurons in Barrington's nucleus: an electron microscope study in the rat.

Direct projections from the medial preoptic area (MPO) to the pontine micturition center neurons directly projecting to the lumbosacral spinal cord were revealed electron microscopically in the rat by a double labeling method. Biotinylated dextran amine (BDA) was injected into the MPO and horseradish peroxidase (HRP) was injected into the lumbosacral cord segments. At light microscopic level, BDA-labeled presumptive axon terminals completely overlapped with HRP-labeled neurons in Barrington's nucleus. Electron microscopic observation showed that some BDA-labeled axon terminals made synaptic contacts with dendrites of HRP-labeled neurons in Barrington's nucleus. The present results indicated that the MPO may be involved in the modulation of the pontine micturition reflex in the rat.

Animals↗
PubMed1999

Nitric oxide inhibits angiotensin II-induced activation of the calcium-sensitive tyrosine kinase proline-rich tyrosine kinase 2 without affecting epidermal growth factor receptor transactivation.

In a previous study, we showed that nitric oxide donors and N-acetylcysteine, either alone or in combination, inhibited the activation of several mitogen-activated protein kinases by angiotensin II in rat cardiac fibroblasts (Wang, D., Yu, X., and Brecher, P. (1998) J. Biol. Chem. 273, 33027-33034). In the present study, we have focused on the mechanism by which nitric oxide exerts this effect on the activation of extracellular signal-regulated kinase (ERK). We contrasted the effects of nitric oxide on ERK activation by angiotensin II and epidermal growth factor (EGF), since the transactivation of the EGF receptor has been implicated as a response to angiotensin II. We found that nitric oxide inhibited ERK activation by angiotensin II but did not inhibit the relatively slight but significant transactivation of the EGF receptor by angiotensin II. The tyrphostin AG1478, known to inhibit EGF receptor phosphorylation, also inhibited the angiotensin II and EGF-induced activation of ERK, the phosphorylation of the EGF receptor, and the subsequent association of Shc and Grb2. Nitric oxide did not affect either EGF receptor phosphorylation or Shc-Grb2 activation induced by either Ang II or EGF. However, the activation of the calcium-sensitive tyrosine kinase PYK2, which occurred in response to angiotensin II, but not EGF, was inhibited by nitric oxide. The data suggested that PYK2 activation may be an important inhibitory site in signaling pathways affected by nitric oxide.

Adaptor Proteins, Signal Transducing↗
PubMed1999

Expression and branch-specific export of mRNA are regulated by synapse formation and interaction with specific postsynaptic targets.

Mechanosensory neurons (SNs) of Aplysia form synapses in culture with some targets (L7), but not others (L11), even when a SN is plated with both targets. We examined whether branch-specific net export of mRNA encoding synapse-specific molecules might contribute to branch-specific synapse formation. Single-cell RT-PCR was used to assay levels of mRNA encoding the SN-specific neuropeptide (sensorin A) and other transcripts in cell bodies and neuritic processes of SNs cultured alone or with synaptic targets. Some mRNAs are exported to neurites, but not others. Sensorin A mRNA is detected only in SN cell bodies and neurites, and expression levels correlate with the strength of the synaptic connections formed with L7 after 4 d in culture. After 4 d, more sensorin A transcripts are detected in SN neurites contacting L7 than in SN neurites contacting L11. The differential expression at 4 d is found even when a single SN contacts both targets simultaneously. By contrast, no significant difference in expression is detected in SN neurites contacting L7 versus L11 after 1 d of coculture. The results suggest that interaction and synapse formation with a specific target lead to a time-dependent change in the branch-specific accumulation of sensorin A mRNA in SNs. Because local protein synthesis at synaptic sites might contribute to synaptic function or plasticity, the results suggest that branch-specific targeting of mRNA encoding synapse-related molecules may contribute to the formation of specific synapses.

Animals↗