Mutation hotspots and DNA methylation.
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5-Methylcytosine↗
Biomedical subjects
M Tang
Publications and source records attributed to M Tang.
Ligand-activated progesterone receptor isoform hPR-A is a stronger transactivator than hPR-B for the expression of IGFBP-1 (insulin-like growth factor binding protein-1) in human endometrial stromal cells.
In human endometrium, the levels of progesterone receptor (PR) isoforms hPR-A and hPR-B are differentially regulated during the reproductive cycle. Progesterone significantly increases the content of hPR-A, the predominant isoform in decidualized stromal cells (1). The purpose of this study was to determine the capacity of hPR-A and hPR-B to transactivate the progestin-dependent target gene in human endometrial stromal cells. We examined the effect of cotransfection of hPR-A or hPR-B on the expression of the human insulin-like growth factor binding protein-1 (IGFBP-1) in endometrial stromal cells. The primary culture of human endometrial stromal cells was transfected with the hPR-A or hPR-B expression vector and the IGFBP-1 promoter construct p275CAT, which contains two functional progesterone response elements (PRE1 and PRE2) in decidualized stromal cells. Medroxyprogesterone acetate (MPA) increased the promoter activities ranging from 1.2- to 27-fold in cells cotransfected with hPR-A or hPR-B in eight endometrial specimens. The promoter activity increased by the hPR-A was significantly higher than hPR-B (15 +/- 8 vs. 4 +/- 2, mean +/- SD; n = 8, P < 0.005). Site-specific mutation showed that the induced activity by hPR-A was mediated through the PRE1 and PRE2 sites. Addition of hPR-B reduced the effect of hPR-A. The high transactivation capacity of hPR-A was also activated by other ligands, progesterone, Org 2058, and norethindrone. These observations indicate that hPR-A is a stronger transactivator than hPR-B for the IGFBP-1 promoter in endometrial stromal cells. Previous studies have shown the progestin-dependent production of IGFBP-1 correlates with its mRNA levels and transcription rate. Thus, we have determined the effect of hPR-A and hPR-B on the production of IGFBP-1 in stromal cells treated with MPA. The production rate in cells uniformly infected with AdPRA (recombinant Ad5-directed PR expression system) was significantly higher (P < 0.001) than the rate in uninfected cells and in cells infected with AdPRB or AdCMV (the Ad5 viral expression vector). This result, in concert with the promoter analysis, provides evidence that hPR-A is a strong inducer for the chromosomal IGFBP-1 gene in endometrial stromal cells.
Adult↗
Prevalence of diabetes in Canadian adults aged 40 years or older.
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Adult↗
[AFLP markers of restoring genes of the wild-abortive hybrid rice].
Fertile and sterile pools were set up by bulked segregant analysis (BSA) based on the selection for the highly fertile and highly sterile plants of Shanyou 63 F2 population. The AFLP analysis of the two pools indicated that 64 primer combinations amplified 3,477 stable and clear bands. Exception of the combination E-AGC/M-CAA, all primer combinations had not detected polymorphism between the two pools. It was proved by investigation of two parents, individuals of F2 segregant population, backbone sterile lines and restorer lines that the polymorphic fragment AP1 generated from the primer E-AGC/M-CAA was associated with the restoring gene. AP1 was a single copy detected by Southern blot hybridization. The distance between AP1 and the restoring gene was 4.76 cM.
Genes, Plant↗
A transient increase in CCK mRNA levels in hippocampus following audiogenic convulsions in audiogenic seizure-prone rats.
AIM: To examine the effects of a single convulsion and multiple convulsions on cholecystokinin (CCK) mRNA expression in hippocampus of audiogenic seizure-prone rats (P77PMC). METHODS: Ringing (electric bell, 100 dB, 60 s) was used to induce convulsions, hippocampal CCK mRNA expression was exhibited by in situ hybridization. RESULTS: 1) The number of CCK mRNA-positive neurons in principal hippocampus of normal rats was 34 +/- 5, which elevated markedly after a single (155 +/- 7, P < 0.01) or multiple convulsions (95 +/- 8, P < 0.01). 2) CCK mRNA levels in multiple consecutive convulsion rats were lower than that in a single convulsion rats (P < 0.01). CONCLUSION: The increased number of CCK mRNA-positive neurons in hippocampus may have important functional consequences in convulsion-associated processes.
Acoustic Stimulation↗
Molecular cloning and protein expression of EC1-2 and EC3-4 epitopes of pemphigus vulgaris antigen.
OBJECTIVE: To clone and express EC1-2 and EC3-4 epitopes of PVA (pemphigus vulgaris antigen, desmoglein-3) in order to diagnose pemphigus and study the relationship between epitopes of PVA and anti-PVA antibody. METHODS: RNA was extracted from keratinocytes and the cDNA of epitopes EC1-2 and EC3-4 was synthesized by reverse transcription. Amplified genes of EC1-2 and EC3-4 were inserted into the expression plasmid, PGEX-4T-1, and transformed into E. coli BL21 by electric transduction. Recombinant fusion proteins of EC1-2 and EC3-4 epitopes were expressed by IPTG induction. These proteins were separated on SDS-PAGE gels and electroblotted to nitrocellulose to detect the anti-PVA antibody. RESULTS: The sequences of cloned EC1-2 and EC3-4 genes were identical to the sequence registered in PC/GENE. Expressed recombinant proteins reacted only to sera from patients with pemphigus vulgaris, not to sera from patients with bullous pemphigoid, systemic lupus erythematosus or normal persons. CONCLUSIONS: These recombinant proteins are very specific in antigenicity. This may provide a new method for the diagnosis of pemphigus vulgaris (PV) or the differential diagnosis of other bullous cutaneous diseases via patient sera. It is also helpful in understanding the relationship between adhesion molecules and the pathogenic mechanism of pemphigus vulgaris.
Autoantibodies↗
[Effect of central administration of motilin on the activity of gastric-related neurons in brain stem and gastric motility of rats].
To investigate the effect of microinjection of motilin into ventral medail hypothalamus (VMH) or intracerebroventricle (icv) on gastric motility, extracellular unit responses of dorsal vagal complex (DVC) in anesthetized rats and gastric motility of conscious rats were recorded. The results are as follows. (1) The firing rate of gastric distention related neurons in DVC was modified. (2) VMH and icv administration of motilin induced obvious enhancement in gastric motility. (3) The effect of motilin on gastric motility was abolished by vagotomy. These results imply that central motilin appears to work as an excitatory neuromodulator in the regulation of gastric motility through VMH-DVC-vagal nerve axis.
Animals↗
[A transient increase in CCK mRNA levels in amygdala following audiogenic seizures in audiogenic seizure-prone rats].
The effects of single and multiple seizures on cholecystokinin (CCK) mRNA levels in amygdala of audiogenic seizure-prone rats (P77PMC) were examined by in situ hybridization. The main results are as follows: (1) CCK mRNA positive neurons (No/0.01 mm(2)) in amygdala showed a transient increase in number from the 8+/-1 to 58+/-5 (P<0.01) in 30 min and then returned to the control value in 2 h (9+/-2, P>0.05), and (2) in the multiple consecutive seizure rats the increase in 30 min (22+/-3) was less than that in the single seizure rats (P<0.01), and the number returned to normal in 1 h (6+/-1, P>0.05). These data indicate that the transient increase in CCK mRNA level in amygdala following single or multiple consecutive seizures of P77PMC may be involved in anti-convulsant mechanisms in response to acute seizures.
Amygdala↗
TNF-alpha-induced growth suppression of CD34+ myeloid leukemic cell lines signals through TNF receptor type I and is associated with NF-kappa B activation.
Conflicting results have been reported regarding the effect of TNF-alpha on the growth of human primitive hemopoietic cells. In this study, we have examined the effect of TNF-alpha on the proliferation of several CD34+/CD38+ (KG-1, TF-1) and CD34+/CD38- (KG-1a, TF-1a) myeloid leukemic progenitor cell lines. Our data show that TNF-alpha markedly inhibits the growth of these cells in both liquid and soft agar cultures. Addition of GM-CSF or IL-3 does not prevent TNF-alpha-induced growth inhibition. Flow cytometry analyses of propidium iodide-stained cells demonstrated cell death of all four cell lines, as judged by the presence of cells with hypodiploid DNA content after exposure of cells to TNF-alpha for 4 days. Annexin V assays detected apoptosis in TF-1, but not in TF-1a, KG-1, and KG-1a cells in terms of translocation of phosphatidylserine shortly after TNF-alpha treatment. Neutralizing anti-TNF receptor type I (TNFR-I; p55) Ab almost completely reversed TNF-alpha-induced growth inhibition in both liquid and soft agar cultures, whereas anti-TNFR-II (p75) Ab had only a marginal effect. TNF-alpha rapidly induced marked activation of nuclear transcription factor NF-kappa B in all 4 cell lines. The majority of this effect was abolished by the type I receptor Ab, whereas the type II receptor neutralizing Ab had no effect. Our data also show that TNF-alpha is incapable of inducing activation of the mitogen-activated protein kinase pathway in these leukemic cell lines.
ADP-ribosyl Cyclase↗
Influence of APOE genotype on familial aggregation of AD in an urban population.
OBJECTIVE: To examine the influence of the proband's APOE genotype on AD among first-degree relatives in a community-based study of African Americans, whites, and Caribbean Hispanics. METHODS: History of AD and demographic information were obtained on 1,073 siblings and parents of 312 patients with AD and 2,722 siblings and parents of 802 nondemented controls. APOE genotyping was performed on all 1,114 patients and controls. RESULTS: A higher proportion of patients with AD (35%) than controls (27%) had one or more APOE-epsilon4 alleles (p = 0.03). When compared with relatives of controls without an APOE-epsilon4 allele, the risk for AD was increased in first-degree relatives of both patients (rate ratio [RR] = 1.9, 95% confidence interval [CI] = 1.2 to 3.1) and controls (RR = 1.8, 95% CI = 1.2 to 2.6) with one or more APOE-epsilone alleles, regardless of ethnic group. There was a similar trend of increased risk in relatives of patients without an APOE-epsilon4 allele, but this was limited to Hispanics and African Americans. CONCLUSIONS: The presence of an APOE-epsilon4 allele increases risk for AD among first-degree relatives, regardless of the probands' disease status, among all ethnic groups. Relatives of patients without an APOE-epsilon4 allele were also at increased risk for AD among Hispanics and African Americans, suggesting that other genes or risk factors may influence risk.
Aged↗
UmuD'(2)C is an error-prone DNA polymerase, Escherichia coli pol V.
The damage-inducible UmuD' and UmuC proteins are required for most SOS mutagenesis in Escherichia coli. Our recent assay to reconstitute this process in vitro, using a native UmuD'(2)C complex, revealed that the highly purified preparation contained DNA polymerase activity. Here we eliminate the possibility that this activity is caused by a contaminating DNA polymerase and show that it is intrinsic to UmuD'(2)C. E. coli dinB has recently been shown to have DNA polymerase activity (pol IV). We suggest that UmuD'(2)C, the fifth DNA polymerase discovered in E. coli, be designated as E. coli pol V. In the presence of RecA, beta sliding clamp, gamma clamp loading complex, and E. coli single-stranded binding protein (SSB), pol V's polymerase activity is highly "error prone" at both damaged and undamaged DNA template sites, catalyzing efficient bypass of abasic lesions that would otherwise severely inhibit replication by pol III holoenzyme complex (HE). Pol V bypasses a site-directed abasic lesion with an efficiency about 100- to 150-fold higher than pol III HE. In accordance with the "A-rule," dAMP is preferentially incorporated opposite the lesion. A pol V mutant, UmuD'(2)C104 (D101N), has no measurable lesion bypass activity. A kinetic analysis shows that addition of increasing amounts of pol III to a fixed level of pol V inhibits lesion bypass, demonstrating that both enzymes compete for free 3'-OH template-primer ends. We show, however, that despite competition for primer-3'-ends, pol V and pol III HE can nevertheless interact synergistically to stimulate synthesis downstream from a template lesion.
Base Sequence↗
Selective decline in memory function among healthy elderly.
OBJECTIVE: To use longitudinally acquired data to establish whether aging is associated with memory decline. BACKGROUND: Memory loss is one of the most frequent complaints among the elderly. Nevertheless, age-related memory decline remains controversial in large part because it has been established with cross-sectional studies. METHODS: A total of 212 community-based healthy people were followed prospectively and evaluated annually with a neuropsychological battery testing memory and other cognitive domains. To control for the learning effect-the improvement in test performance associated with repeated exposure-longitudinal performance was compared between two age groups. RESULTS: The older age group displayed a relative decline in memory performance with time. In contrast to memory, a relative age-related decline was not observed in tests of language, visuospatial ability, and abstract reasoning. Furthermore, within the memory domain, age-related decline was restricted to a specific aspect of memory, manifesting only in a measure sensitive to the acquisition and early retrieval of new information, and not in a measure of memory retention. This profile of age-related cognitive decline anatomically localizes to the hippocampal formation. CONCLUSION: This study establishes age-related memory decline using longitudinal data, and shows that this decline does not occur diffusely across multiple cognitive domains. Both early AD as well as non-AD processes likely contribute to age-related memory decline, and continued follow-up may reveal distinguishing features between these two.
Aged↗
Modification of beta 2glycoprotein I by glutardialdehyde. Conformational changes and aggregation accompany exposure of the cryptic autoepitope.
Autoantibodies from patients with antiphospholipid syndrome (APS) recognize an epitope on beta 2glycoprotein I (beta 2 GPI) only when native beta 2 GPI is adsorbed on surfaces composed of anionic phospholipids or oxidized polystyrene. beta 2 GPI was modified with the crosslinking agent, glutardialdehyde (GDA), which induced exposure of the anti-beta 2 GPI epitope at GDA:beta 2 GPI mol ratios in the range of 500-2000. A second crosslinking agent, dimethyl-suberimidate (DMS), did not expose the epitope, which may be a consequence of its having less tendency than GDA to form intermolecular links. SDS-PAGE experiments demonstrate that GDA does promote extensive intermolecular crosslinking of beta 2 GPI, and DMS does not. Formaldehyde also reacts with the lysine residues of beta 2 GPI, but does not expose the epitope. The circular dichroism spectra of native and modified beta 2 GPI confirm that GDA induces changes in conformation that are qualitatively different from those caused by formaldehyde. These data provide evidence that binding of lysine residues is not a sufficient condition for exposure of the autoepitope, and also support the likelihood that anti-beta 2 GPI antibodies bind only to aggregates of the protein. Thus, by synthesizing an active holoantigen of beta 2 GPI, conditions were defined that are necessary for binding of human autoantibodies.
Autoantibodies↗
Effect of segregated early weaning on postweaning small intestinal development in pigs.
The effect of segregated early weaning (SEW) on postweaning small intestinal development was investigated in SEW and control (CON) pigs. Small intestines were collected from a total of 15 pigs killed at 11 (preweaning), 15 (3 d postweaning), and 34 d of age. At 3 d postweaning, the SEW and CON pigs had shorter villi (P<.01), deeper crypts (P<.01), and reduced (P<.01) ratios of villus height:crypt depth (V:C) compared with preweaning. Weaning also reduced specific activities of lactase (P<.01) in duodenum and ileum and alkaline phosphatase (ALP) (P<.05) in duodenum and jejunum. Sucrase activity in the three regions of the small intestine marginally decreased in both groups at 3 d postweaning. The mucosal protein:DNA ratio in duodenum and jejunum increased (P<.05) in SEW and CON pigs at 3 d postweaning compared with preweaning pigs. The SEW and CON treatments resulted in differences in postweaning gut development. At 15 d of age in SEW pigs, the mucosal protein:DNA ratio in duodenum and jejunum were 20 and 25.5% (P<.05) less, respectively, than those in CON pigs. However, at 34 d, these ratios in duodenum, jejunum, and ileum were 43.5 (P<.05), 24.3, and 32.9% (P<.05) greater, respectively, in SEW pigs than in CON pigs. Longer villi, shorter crypts (P<.01), and higher V:C ratios (P<.01) in jejunum and ileum were observed in SEW pigs vs CON pigs at 34 d of age. The specific activities of lactase in duodenum (P<.01) and jejunum (P<.05) and of ALP in duodenum (P<.01) were higher in SEW pigs. Sucrase activity in duodenum, jejunum, and ileum was 21.7, 46.3 (P<.05), and 11.2% greater in SEW pigs at 34 d of age. These results demonstrate differences in postweaning gut development between SEW and CON pigs. Furthermore, the number of intraepithelial lymphocytes in jejunum was greater (P<.001) in 34-d-old SEW pigs compared with CON pigs. Microscopy revealed a thick mucus coating over epithelial cells in the ileum of 34-d-old CON pigs that was not apparent in the SEW pigs. These observations are consistent with reduced pathogen exposure associated with SEW. We suggest that segregated early weaning advances postweaning gut maturation, which is consistent with improved growth and feed efficiency observed in SEW pigs.
Animals↗
Variable levels of mosaicism for trisomy 21 in a non-immune hydropic infant with chylothorax.
We report the first case of mosaic trisomy 21 with non-immune hydrops fetalis and bilateral chylothoraces. Prenatal fetal blood karyotype analysis of 15 fetal cells revealed a 46,XX karyotype. Aggressive prenatal management, including fetal thoracocentesis and pleuro-amniotic shunt, was performed. A clinical phenotype of Down syndrome was apparent after the gross oedema had subsided. Subsequent chromosome study of neonatal blood lymphocytes showed mosaic trisomy 21 with 23 per cent trisomic cells. Review of the initial fetal blood sample identified trisomy in 5 per cent of 134 cells. Follow-up study at five months showed no trisomy 21 in 100 cells. This case illustrates the variable levels of mosaicism manifest in the peripheral blood of an infant with obvious Down syndrome phenotype, and the limitation of cytogenetic analysis of peripheral lymphocytes alone in prenatal and postnatal detection of low levels of mosaicism.
Adult↗
[Changes in the mRNA concentration of preprocholecystokinin in rat cerebral cortex and hippocampus after gastric distension].
Cholecyctokinin-octapeptide (CCK-8) is one of the brain-gut peptides widely distributed in neurons of the central nervous system, especially in cerebral cortex and hippocampus. This peptide is thought as a neurotransmitter or modulator. The role of central CCK in the integration of gastric motility and food intake is still unclear. The present investigation was undertaken to see whether the gastric distension exerts some effect on the expression of CCK mRNA in cerebral cortex and hippocampus by means of in situ hybridization and semi-quantitative RT-PCR techniques. The results are as follows. (1) Discrete positive hybridization cells were seen in cerebral cortex and hippocampus in control group. (2) Significant increases of CCK mRNA expression in cerebral cortex and hippocampus produced by gastric distention observed by increased of the volume, the number, the IOD and the SA of positive cells. (3) Amplified bands of the expected size of 158 base pairs were found in cerebral cortex and hippocampus, and signals of gastric distention group were higher than those of control group. The results from RT-PCR assay are in agreement with those based on in situ hybridization. These results imply that biosynthesis of CCK-containing neurons in cerebral cortex and hippocampus is accelerated by afferent signals from gastrointestinal system and may be involved in regulation of gastric motility and food intake.
Animals↗
[Effect of chronic hypoxia on the calcium and potassium current of myocytes of the right ventricle in guinea pig].
To explore the effect of chronic hypoxia on calcium and potassium currents of the right ventricle myocytes in the guinea pig, the cell membrane capacities, calcium and delayed rectifier potassium current were recorded using the whole-cell patch clamp technique from single right ventricle myocytes in guinea pigs under chronic hypoxia. The result demonstrated that the cell membrane capacities of the hypoxic group were larger than those of the control; between test potential of -20 mV to +20 mV, the calcium current density of the myocytes of the chronic hypoxic group was less than that of the control; the amplitude of IK of the myocytes of the chronic hypoxia group were less than that of the control group between test potential of +20 mV to +60 mV, and the IK density of the hypoxic group was also less than that of the control group between -20 mV to +60 mV. Consequently, it is suggested that chronic hypoxia may cause an increase of the membrane capacity, a decrease of the calcium current density of ventricle myocytes and a delay of the rectifier potassium current amplitude and density. All these observations provide information for the ionic basis of the attenuated contraction of cardiac muscles and prolonged action potential duration of hypoxic guinea pigs.
Action Potentials↗
[A clinical and experimental study on autologous nail transplantation ophthalmoplasty].
OBJECTIVE: To seek for better materials for ophthalmoplasty. METHODS: The nails were used as autografts in an experimental and a clinical study. The paws were subcutaneously grafted in the backs of 15 rabbits. The nails were used as the tarsus to constitute the lower eyelid on one patient. On another patient, the toenails were used to restore fracture of the base of the orbit. RESULTS: Without reject reaction, the paws were encapsulated by fibrous tissue ten weeks after grafting. The six patients were followed up for 1 to 5 years and were satisfied with the plastic operations. CONCLUSION: The nail is a practical and an effective autograft in ophthalmoplasty.
Animals↗