[Birth cohort studies in China: a review].

With longer than 100-year experience of development, methods used on birth cohort study have been viewed as having important roles in exploring the probable effects of health and environment exposure both prior to and during the pregnancy in the life circle as infants, children, adolescents, adults, and the elderly. However in China, birth cohort studies started late but with rapid development. Recently, some well-known methods on birth cohort studies were established in mainland China, Hong Kong and Taiwan area. This paper presented an overall review on the progress about birth cohort studies and their prospects, in China.

Patients' perceptions of day surgery: a survey study in China surgery.

OBJECTIVE: To investigate patients' perceptions of day surgery, specifically their convenience; social, functional and economic values; risk perceptions; and patient satisfaction. DESIGN: Cross-sectional questionnaire survey. SETTING: West China Hospital in Chengdu City, China. PARTICIPANTS: All the day-surgery patients admitted to the Centre for Day Surgery in December 2011. MAIN OUTCOME MEASURES: Demographic profiles, each patient's value and risk perceptions about day surgery, as well as overall satisfaction with day surgery. RESULTS: Convenience value and social value were emphasised by 87% and 60% of the 153 valid respondents, respectively. Comparatively speaking, functional and economic value were respectively chosen by 50% and 43% of the respondents, while 75% worried about postoperative complications and adverse events, only 53% and 27% worried about rehabilitation knowledge and psychological risks, respectively. More than 95% of the respondents were satisfied with the clinic service and staff attitudes, hospital surgery environment, operating skills and results, but fewer (84%) were satisfied with the communication processes surrounding day surgery. CONCLUSION: Patients exhibited high acceptance and satisfaction regarding day surgery. The convenience experienced by patients and their families is the main perceived value of day surgery. Nevertheless, during the recovery process patients are concerned about possible adverse events, treatment of postoperative complications, and lack of information. These aspects of care delivery warrant improvement through redesign of the day surgery service.

Induction of ID1 expression and apoptosis by the histone deacetylase inhibitor (trichostatin A) in human acute myeloid leukaemic cells.

INTRODUCTION: ID1, founding member of the inhibitor of differentiation (ID) family, is involved in cell population growth, apoptosis and tumourigenesis. METHODS AND RESULTS: We investigated mRNA levels of ID1 in human myeloid leukaemic cell lines and in specimens of patients with acute myeloid leukaemia (AML), using semiquantitative reverse transcription-polymerase chain reaction, and protein levels of ID1 in human myeloid leukaemic cell lines using Western blot analysis. Six of seven AML cell lines and 12 of 15 AML patient samples were found to have barely detectable ID1 mRNA. All of these cell lines showed the same levels of protein in proportion to levels of mRNA. Two of the AML cell lines with low ID1 expression, KG1 and KG-1a, were chosen for treatment with either the DNA demethylation reagent, 5-aza-2'-deoxycytidine (DAC), or the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA). These treatments were alone or in combination, and ID1 expression was induced by both DAC and TSA. No hypermethylated ID1 gene promoter was detected in the majority of the cell lines and patient specimens, by methylation-specific polymerase chain reaction, suggesting that induction of ID1 in KG1 and KG-1a was not due to direct demethylation of the ID1 gene promoter. Chromatin immunoprecipitation showed that accumulation of acetyl-histone H3 and release of HDAC1 were correlated with ID1 induction by these drugs. Flow cytometric assay demonstrated more apoptosis induced by TSA or TSA in combination with DAC, in both KG-1 and KG-1a cell lines. Increase of intracellular reactive oxygen species was observed when treated with TSA. CONCLUSION: Most AML cell lines and human AML samples have very low levels of expression of ID1. TSA or TSA in combination with DAC is able to restore ID1 expression in low ID1-expressing AML cell lines by re-activating the aberrantly deacetylated promoter, and this also results in more apoptotic cell death, in which ID1 and the redox pathway may be involved.

Association of gastric cancer with tyrosine hydroxylase gene polymorphism in a northwestern Chinese population.

Gastric cancer (GC) is a common and complex disease caused by multifactors. The aim of our study was to investigate the association of the common polymorphisms detected in insulin-like growth factor (IGF)-II, IGF-1 receptor, insulin-like growth factor binding protein 1 (IGFBP1), insulin (INS) and tyrosine hydroxylase (TH) with susceptibility to GC in a northwestern Chinese population. One hundred and fifty-four GC patients and 166 healthy controls were investigated in our study. The genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of CC and CT genotypes of TH were significantly higher in GC patients than in controls, as the odds ratios were 3.03 (95%CI 1.438-6.362, P=0.003) and 1.97 (95%CI 1.218-3.167, P=0.005), respectively. No association was found between the polymorphisms of IGF-II ApaI, insulin-like growth factor-1 receptor MnlI, IGFBP1 Bgl II and INS-23HphI and the development of GC. The presence of CC and CT genotypes of TH was associated with a significantly increased risk of GC. But the polymorphisms of other genes detected did not indicate an increased risk of GC in the investigated population.

Analysis of polyethylene-glycol-polylactide nano-dimension artificial red blood cells in maintaining systemic hemoglobin levels and prevention of methemoglobin formation.

We have recently reported our study on novel nano-dimension red blood cell (rbc) substitute based on ultrathin PEG-PLA membrane nanocapsules (80-150 nanometer diameter) containing hemoglobin (Hb) and enzymes. These have a markedly increased the circulation half-times as compared to our earlier PLA membrane nanocapsules. In the present study to be reported here, instead of looking at this from a pharmacodynamic point of view, we design the Hb nanocapsules from the point of view of transfusion medicine. For instance, the maximal levels of systemic non-red blood cell (rbc) Hb that can be attained after one infusion of 30% blood volume of 10 gm/dl Hb in the form of different types of PEG-PLA Hb nanocapsules or polyHb. Also the length of time one infusion can maintain a given systemic non-rbc hemoglobin Hb level. Of the two types of polyhemoglobins similar to those in clinical trials but prepared in this laboratory, the maximal levels of Hb reached were 3.35 gm/dl and 3.10 gm/dl respectively. The times for the hemoglobin level to fall to 1.67 gm/dl were 14 hours and 10. hours respectively, corresponding to 24 hours and 17 hours in human. The best PEG-PLA Hb nanocapsules are prepared using a combination of the following 4 factors: use of polymerized Hb, the use of higher M.W. PLA, the use of higher concentrations of PEG-PLA and the crosslinking of the newly formed PEG-PLA Hb nanocapsules. With this, the maximal non-rbc systemic Hb reached was 3.66 gm/dl and the time to reach 1.67 gm/dl was 24.2 hours, or 41.5 hours in human if extrapolated using the results obtained with polyHb in rats.

Conserved synteny between the Fugu and human PTEN locus and the evolutionary conservation of vertebrate PTEN function.

Mutations of PTEN, which encodes a protein-tyrosine and lipid phosphatase, are prevalent in a variety of human cancers. The human genome 'draft' sequence still lacks organization and much of the PTEN and adjacent loci remain undefined. The pufferfish, Fugu rubripes, by virtue of having a compact genome represents an excellent template for rapid vertebrate gene discovery. Sequencing of 56 kb from the Fugu pten (fpten) locus identified four complete genes and one partial gene homologous to human genes. Genes neighboring fpten include a PAPS synthase (fpapss2) differentially expressed between non-metastatic/metastatic human carcinoma cell lines, an inositol phosphatase (fminpp1) and an omega class glutathione-S-transferase (fgsto). We have determined the order of human BAC clones at the hPTEN locus and that the locus contains hPAPSS2 and hMINPP1 genes oriented as are their Fugu orthologs. Although the human genes span 500 kb, the Fugu genes lie within only 22 kb due to the compressed intronic and intergenic regions that typify this genome. Interestingly, and providing striking evidence of regulatory element conservation between widely divergent vertebrate species, the compact 2.1 kb fpten promoter is active in human cells. Also, like hPTEN, fpten has a growth and tumor suppressor activity in human glioblastoma cells, demonstrating conservation of protein function.

Two future generations of blood substitutes based on polyhemoglobin-SOD-catalase and nanoencapsulation.

This paper discusses our research on two new generation blood substitutes. One is based on the crosslinking of hemoglobin, superoxide dismutase(SOD) and catalase (CAT) to form polyhemoglobin-SOD-CAT. This is being investigated for use in conditions with potential problems related to ischemia-reperfusion injuries as in severe hemorrhagic shock, stroke and other conditions. The second one is based on biodegradable polymeric nanocapsules containing hemoglobin and enzymes. In this form, the hemoglobin and enzymes are separated from the external environment. Furthermore, modifications of the polymeric membrane can result in increase in circulation time.

Sustained drug release characteristics of biodegradable composite poly(d,l)lactic acid-poly(l)lactic acid microcapsules containing ciprofloxacin.

Ciprofloxacin polylactic microcapsules were prepared by the phase separation process. Two types of polylactic acid, poly(d,l)lactic acid and poly(l)lactic acid were combined as membrane materials to prevent the aggregation which happened frequently in the phase separation process. The polymer compositions of the microcapsules can influence the release rate of Ciprofloxacin. The optimal release rate of the drug can be obtained by modifying microcapsule compositions. Poly(d,l)lactic acid is superior in slowing the rate of drug release than poly(l)lactic acid. However, poly(l)lactic acid is necessary in the preparation of the microcapsules to prevent aggregation.

Biodegradable polylactic acid nanocapsules containing ciprofloxacin: preparation and characterization.

Nanocapsules have been studied as carriers to deliver different types of drugs into macrophages. Many studies have shown that the nanocapsules can enhance the biological response of the drugs. In this study, we prepared ciprofloxacin nanocapsules with polylactic acid. The ciprofloxacin is an antibacterial agent. The ciprofloxacin nanocapsules prepared have a means diameter of 168 nm. In phosphate buffer at pH 7.4, high encapsulation rate was obtained. The nanocapsules with high encapsulation rate can also be made from ciprofloxacin base.

Insulin secretagogues activate the secretory granule receptor-like protein-tyrosine phosphatase IAR.

To investigate the potential role of protein-tyrosine phosphatases (PTPs) in regulated secretion, cellular PTP activity was measured in pancreatic beta cell lines after exposure to insulin secretagogues. A peak of elevated PTP activity was detected in whole cell lysates after 15-20 min of treatment of the cells with high KCl, glucose, or TPA, which did not appear upon treatment with control compounds. Neither was it detected in cells that do not undergo regulated secretion. The PTP activation was transient, SDS-resistant, and localized to the cytoskeleton fraction of cells. The cytoskeletal localization of IAR, a receptor-like PTP associated with secretory granules of neuroendocrine cells, suggested the possibility that IAR is the secretagogue-activated PTP. The transient expression of human IAR in betaTC3 and HIT-T15 beta cells, followed by treatment with secretagogues or control compounds and immunoprecipitation of human IAR, showed that immunoprecipitates from the secretagogue-treated cells contained an elevated PTP activity. The secretagogue-induced activation of IAR had identical kinetics to that of the endogenous PTP. Although ectopic IAR was present in membrane and cytoskeletal fractions from the cells, only the cytoskeleton-associated IAR could be activated. Thus IAR represents the endogenous secretagogue-responsive PTP, or at least a component of it, and is one of the few receptor-like PTPs for which enzymatic activation has been demonstrated. Insulin secretion is detected prior to IAR activation, suggesting that IAR is not required for immediate secretion but likely plays a role in events downstream of insulin secretion or in another pathway related to the specialized function of secretory cells.

Antibodies to the protein tyrosine phosphatases IAR and IA-2 are associated with progression to insulin-dependent diabetes (IDDM) in first-degree relatives at-risk for IDDM.

Insulin-dependent diabetes mellitus (IDDM) is preceded by the presence of antibodies against islet proteins including a protein tyrosine phosphatase (PTP) designated IA-2. Recently, we cloned a novel PTP named IAR which shares 43% sequence identity with IA-2 and is recognised by antibodies from a majority of patients with IDDM. The aim of the present study was to determine whether IAR antibodies (IAR Ab) or IA-2 antibodies (IA-2 Ab) are associated with progression to IDDM in first-degree relatives "at-risk" for IDDM (operationally defined as those with islet cell antibodies [ICA] > or = 20JDFU or insulin autoantibodies [IAA] > or = 100 nU/ml), and to examine combinations of IAR Ab and IA-2 Ab in these subjects. The sensitivity and specificity of these antibodies were also examined in patients with recent-onset IDDM. Using Cox's Proportional Hazards Model, the number of siblings with IDDM was associated with progression to IDDM in "at-risk" relatives, but other covariables (age, sex, number of affected offspring or parents) were not significantly associated. Using number of affected siblings as a covariable, both IAR and IA-2 antibodies were significantly associated with progression to IDDM (p < 0.005). Combinations of both antibodies, however, did not result in a significantly stronger association with progression to IDDM. The threshold of positivity for IAR Ab (0.5 units) and IA-2 Ab (3.0 units) assays was adjusted to give the same specificity (97.9%) for each assay in 144 healthy control subjects, to allow standardised comparisons. Levels of IAR Ab and IA-2 Ab were strongly correlated in 53 recent-onset IDDM patients (r = 0.70, p < 0.0001) but 11.3% had IAR Ab in the absence of IA-2 Ab and 16.9% had IA-2 Ab in the absence of IAR Ab. The sensitivity for IDDM (defined as the proportion of IDDM patients positive) was 56.6% for IAR Ab and 62.3% for IA-2 Ab. We conclude that there is considerable overlap in IA-2 Ab and IAR Ab positivity, although either antibody can occur independently in IDDM patients. Both IAR Ab and IA-2 antibodies are associated with progression to IDDM in first-degree relatives at-risk of IDDM, but the use of IAR and IA-2 antibodies in combination are not significantly more strongly associated with progression than single antibodies. IAR Ab may play an important role in the prediction of IDDM.

Preparation of polylactic acid microcapsules containing ciprofloxacin.

Microcapsules have been used as drug delivery systems in the pharmaceutical field for sustained or controlled release of drug, and for artificial cells and organs. Biodegradable polymers, especially polylactic acid, have been widely used in this field. In this study, an attempt was made to develop a new method to prepare polylactic acid microcapsules for drug delivery. The biodegradable polylactic acid microcapsules were made by the phase separation process: two types of polylactic acid, poly[(D,L)lactic acid] and poly[(L)lactic acid] were combined as the membrane material. Because of the difference of the crystal properties of the two polymers, the aggregation which happens frequently in the phase separation process was prevented. As a model drug, Ciprofloxacin was encapsulated in the polylactic acid microcapsules.

Oligodendrocyte population dynamics and the role of PDGF in vivo.

Oligodendrocyte progenitors originate near the floor plate of the spinal cord, then proliferate and migrate throughout the cord before giving rise to oligodendrocytes. Progenitor cell proliferation stops before birth because the cell cycle slows down, linked to an increase in differentiation and death. Experiments with transgenic mice show that platelet-derived growth factor (PDGF) drives progenitor cell division and suggest that slowing of and exit from the cycle reflects a decline in PDGF signaling. Overexpressing PDGF induces hyperproliferation of progenitor cells and excessive, ectopic production of oligodendrocytes. However, the superfluous oligodendrocytes die at an immature stage of differentiation, leaving a normal complement of myelin-forming cells. Therefore, cell survival controls override proliferation controls for determining the final number and distribution of mature oligodendrocytes.

Identification of a domain on the beta-subunit of the rod cGMP-gated cation channel that mediates inhibition by calcium-calmodulin.

The cGMP-gated cation channel mediating phototransduction in retinal rods has recently been shown to be inhibited by calcium-calmodulin, through direct binding of the latter to the beta-subunit of the heterotetrameric channel complex. Here, we report the characterization of this inhibition and the identification of a domain crucial for this modulation. Heterologous expression of the alpha- and beta-subunits of the human rod channel in HEK 293 cells produced a cGMP-gated current that was highly sensitive to calcium-calmodulin, with half-maximal inhibition at approximately 4 nM. In biochemical and electrophysiological experiments on deletion mutants of the beta-subunit, we have identified a region on its cytoplasmic N terminus that binds calmodulin and is necessary for the calmodulin-mediated inhibition of the channel. However, in gel shift assays and fluorescence emission experiments, peptides derived from this region indicated a low calmodulin affinity, with dissociation constants of approximately 3-10 microM. On the C terminus, a region was also found to bind calmodulin, but it was likewise of low affinity, and its deletion did not abolish the calmodulin-mediated inhibition. We suggest that although the identified region on the N terminus of the beta-subunit is crucial for the calmodulin effect, other regions are likely to be involved as well. In this respect, the rod channel appears to differ from the olfactory cyclic nucleotide-gated channel, which is also modulated by calcium-calmodulin.

Identification of components of a phosphoinositide signaling pathway in retinal rod outer segments.

Phototransduction in retinal rods involves a G protein-coupled signaling cascade that leads to cGMP hydrolysis and the closure of cGMP-gated cation channels that are open in darkness, producing a membrane hyperpolarization as the light response. For many years there have also been reports of the presence of a phosphoinositide pathway in the rod outer segment, though its functions and the molecular identities of its components are still unclear. Using immunocytochemistry with antibodies against various phosphoinositide-specific phospholipase C (PLC) isozymes (beta1-4, gamma1-2, and delta1-2), we have found PLCbeta4-like immunoreactivity in rod outer segments. Similar experiments with antibodies against the alpha-subunits of the G(q) family of G proteins, which are known to activate PLCbeta4, have also demonstrated G(alpha11)-like immunoreactivity in this location. Immunoblots of total proteins from whole retina or partially purified rod outer segments with anti-PLCbeta4 and anti-G(alpha11) antibodies gave, respectively, a single protein band of the expected molecular mass, suggesting specific labelings. The retinal locations of the two proteins were also supported by in situ hybridization experiments on mouse retina with probes specific for the corresponding mouse genes. These two proteins, or immunologically identical isoforms, therefore likely mediate the phosphoinositide signaling pathway in the rod outer segment. At present, G(alpha11) or a G(alpha11)-like protein represents the only G protein besides transducin (which mediates phototransduction) identified so far in the rod outer segment. Although absent in the outer segment layer, other PLC isoforms as well as G(alpha q) (another G(q) family member), are present elsewhere in the retina.

Origins of spinal cord oligodendrocytes: possible developmental and evolutionary relationships with motor neurons.

Spinal cord oligodendrocytes develop from migratory glial progenitor cells that are generated by a small subset of neuroepithelial cells in the ventral part of the neural tube. Specification of these neuroepithelial oligodendrocyte precursors, in common with other ventral cells such as motor neurons, depends on morphogenetic signals from the notochord and/or floor plate. The ventrally derived signals can be mimicked in vitro by purified Sonic hedgehog (Shh) protein. Oligodendrocytes and motor neurons are induced over the same range of concentrations of Shh, consistent with the idea that Shh might specify a common precursor of motor neurons and oligodendrocytes. A lineage relationship between motor neurons and oligodendrocytes has previously been suggested by clonal analysis in the embryonic chick spinal cord. We propose a lineage diagram that connects oligodendrocytes and motor neurons and that takes into account the fact that motor neurons and oligodendrocyte precursors are generated at different times during development. Oligodendrocytes might originally have evolved to ensheath motor axons and facilitate a rapid escape response. If so, oligodendrocyte ontogeny and phylogeny might share a common basis.

Cloning and characterization of islet cell antigen-related protein-tyrosine phosphatase (PTP), a novel receptor-like PTP and autoantigen in insulin-dependent diabetes.

Cloning of the cDNA encoding a novel human protein- tyrosine phosphatase (PTP) called islet cell antigen-related PTP (IAR) predicts a receptor-like molecule with an extracellular domain of 614 amino acids containing a hydrophobic signal peptide, one potential N-glycosylation site, and an RGDS peptide which is a possible adhesive recognition sequence. The 376-amino acid intracellular region contains a single catalytic domain. Recombinant IAR polypeptide has phosphatase activity. Northern blot analysis shows tissue-specific expression of two IAR transcripts of 5.5 and 3. 7 kilobases, which are most abundant in brain and pancreas. The IAR PTP is homologous in its intracellular region to IA-2, a putative PTP that is an insulin-dependent diabetes mellitus (IDDM) autoantigen. IAR is also reactive with IDDM patient sera. IAR and IA-2 may distinguish different populations of IDDM autoantibodies since they identify overlapping but nonidentical sets of IDDM patients. Thus IAR is likely to be an islet cell antigen useful in the preclinical screening of individuals for risk of IDDM.

Molecular cloning, functional expression and chromosomal localization of a human homolog of the cyclic nucleotide-gated ion channel of retinal cone photoreceptors.

We have cloned from human retina a cyclic nucleotide-gated (CNG) ion channel that is distinct from the one found in rod photoreceptors. This channel protein is highly homologous to the CNG channel that recently has been cloned from bovine testis and kidney and has been shown to be present in retinal cone photoreceptors. When expressed in human embryonic kidney cells, the protein forms functional ion channels with properties broadly similar to those described for the cloned bovine channel. The gene for this channel resides on chromosome 2.