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Biomedical subjects

Mei Li

Publications and source records attributed to Mei Li.

At least 19 recordsLinked to original sources
PubMed2026

Xp21 contiguous gene deletion syndrome presenting as congenital adrenal hypoplasia: molecular diagnosis and clinical re-evaluation of a pedigree.

OBJECTIVE: To investigate the molecular etiology in a male child clinically suspected of congenital adrenal hyperplasia (CAH) with negative conventional genetic testing, and to elucidate the genetic characteristics of his pedigree. METHODS: Clinical data from the proband and his family members were collected. Molecular diagnostics proceeded sequentially: initial targeted CAH testing (CYP21A2 and POR sequencing/MLPA, plus targeted NR0B1 CNV analysis) was followed by whole-exome sequencing coupled with genome-wide CNV analysis. RESULTS: The proband presented with neonatal cyanosis and hyperpigmentation. Laboratory tests showed markedly elevated ACTH (354.68 pmol/L) and low aldosterone (57.24 pg/mL). Molecular genetic testing identified a hemizygous deletion of approximately 4.44 Mb at Xp21.3-p21.1 (chrX:g.27080000_31520000), encompassing the NR0B1, GK, IL1RAPL1, and DMD genes. CNV-seq confirmed that the mother carried a heterozygous deletion of 4.38 Mb in the same region, while the father and four maternal aunts showed normal genotypes. CONCLUSION: This study ultimately diagnosed the proband with Xp21 contiguous gene deletion syndrome. The adrenal insufficiency resulted from X-linked congenital adrenal hypoplasia (AHC) due to NR0B1 haploinsufficiency, rather than CAH. These findings highlight the considerable clinical overlap between AHC and CAH, indicating that CNV analysis of the Xp21 region should be included in the diagnostic workup for male infants with suspected CAH but negative routine genetic testing. This provides a basis for the precise diagnosis and genetic counseling of such patients.

Humans↗
PubMed2026

Seawater immersion reshapes the temporal dynamics of traumatic brain injury and reveals mitochondrial oxidative stress as a modifiable therapeutic target.

Traumatic brain injury (TBI) evolves through time-dependent secondary injury, but whether seawater (SW) immersion merely amplifies pathology or reshapes the temporal trajectory of post-traumatic biology remains unclear. Here, we applied time-resolved proteomics to mouse brains after controlled cortical impact (CCI) with or without artificial SW immersion at 1, 3, 7, and 28 days post-injury. Trajectory-based proteomic analysis revealed that SW immersion altered the direction, magnitude, timing, persistence, and recovery of protein responses, rather than simply intensifying TBI-induced changes. This remodeled trajectory exhibited phase-specific patterns, including SW-dominant, synergistically enhanced, and attenuated responses, highlighting mitochondrial oxidative stress, inflammatory activation, complement/coagulation disturbance, and impaired structural repair. Phenotypic validation confirmed phase-specific deficits, including acute inflammatory-redox injury, impaired neuronal survival, chronic axon-myelin disruption, and incomplete behavioral recovery. SS-31 partially mitigated selected inflammatory, redox, neuronal, and white matter abnormalities, supporting mitochondrial oxidative stress as a modifiable node rather than the sole driver of trajectory remodeling. These findings identify seawater immersion as a temporal modifier of secondary injury and emphasize that environmental trauma may require trajectory-informed, phase-specific therapeutic interventions.

Animals↗
PubMed2025

Stereo-cell: Spatial enhanced-resolution single-cell sequencing with high-density DNA nanoball-patterned arrays.

Single-cell sequencing technologies have advanced our understanding of cellular heterogeneity and biological complexity. However, existing methods face limitations in throughput, capture uniformity, cell size flexibility, and technical extensibility. We present Stereo-cell, a spatial enhanced-resolution single-cell sequencing platform based on high-density DNA nanoball (DNB)-patterned arrays, which enables scalable and unbiased cell capture at a wide input range and supports high-fidelity transcriptome profiling. Stereo-cell further allows integration with imaging-based modalities and multiomics strategies, including immunofluorescence and epitope profiling. This platform is also compatible with profiling extracellular vesicles, microstructures, and large cells, whereas its spatial resolution facilitates in situ analysis of cell-cell interactions, cellular microenvironments, and subcellular transcript localization. Together, Stereo-cell provides a flexible framework for expanding single-cell research applications.

Animals↗
PubMed2003

The effect of stimulus-onset asynchrony on human visual event-related potentials during simple and choice reaction paradigms under constant or random conditions.

Visual event-related potentials (ERPs) were recorded during an oddball paradigm (OBP) and a simple reaction paradigm (SRP) to investigate the effect of stimulus-onset asynchrony (SOA) on ERPs under constant and random conditions in nine healthy individuals. NA was obtained by subtracting ERPs for SRP from those to the frequent nontarget of OBP. N2 was obtained by subtracting ERPs to the frequent nontarget from those to the rare target of OBP. N1, P2, and P3 latencies during OBP were shorter, and N1 amplitude of OBP, P1, and P2 amplitude of SRP, and NA amplitude were larger under constant conditions than under random conditions. We suggest that visual information processing is faster and more effective under constant conditions than under random conditions. NA potential related to the pattern recognition processing was significantly interfered with under random conditions, whereas N2 potential related to the stimulus classification was less influenced by the rhythm. The visual selective processing activity was influenced by the SOA with the positive shift of the waveform "20% rare target of OBP-100% target of SRP" under random conditions.

Adult↗
PubMed2003

MultiPipMaker and supporting tools: Alignments and analysis of multiple genomic DNA sequences.

Analysis of multiple sequence alignments can generate important, testable hypotheses about the phylogenetic history and cellular function of genomic sequences. We describe the MultiPipMaker server, which aligns multiple, long genomic DNA sequences quickly and with good sensitivity (available at http://bio.cse.psu.edu/ since May 2001). Alignments are computed between a contiguous reference sequence and one or more secondary sequences, which can be finished or draft sequence. The outputs include a stacked set of percent identity plots, called a MultiPip, comparing the reference sequence with subsequent sequences, and a nucleotide-level multiple alignment. New tools are provided to search MultiPipMaker output for conserved matches to a user-specified pattern and for conserved matches to position weight matrices that describe transcription factor binding sites (singly and in clusters). We illustrate the use of MultiPipMaker to identify candidate regulatory regions in WNT2 and then demonstrate by transfection assays that they are functional. Analysis of the alignments also confirms the phylogenetic inference that horses are more closely related to cats than to cows.

Algorithms↗
PubMed2003

Sp1 and Sp3 Are important regulators of AP-2gamma gene transcription.

AP-2gamma is a member of the AP-2 transcription factor family, is highly enriched in the trophoblast cell lineage, and is essential for placental development. In an effort to identify factors regulating AP-2gamma gene expression, we isolated and characterized the promoter and 5'-flanking region of the mouse and human AP-2gamma genes. The transcription start site of the mouse AP-2gamma gene was mapped by primer extension and 5' rapid amplification of cDNA ends. Deletion analysis of the 5'-flanking region revealed a 704-base pair (bp) sequence located approximately 6 kilobases (kb) upstream of the transcription start site that is required for enhanced expression in trophoblast cells. Additional gene transfer studies showed that basal promoter activity resides within a highly conserved, approximately 200-bp DNA sequence located immediately upstream of the transcription start site. The conserved region is highly GC-rich and lacks typical TATA or CCAAT boxes. Multiple potential Sp- and AP-2-binding sites are clustered within this region. Electrophoretic mobility shift assays demonstrated that Sp1 and Sp3 bind to three sites in the promoter region of the mouse AP-2gamma gene. Combined mutation of the three putative Sp sites reduced promoter activity by 80% in trophoblast and nontrophoblast cells, demonstrating the functional importance of these sites in regulating AP-2gamma gene expression. In summary, we have identified a potential trophoblast cell-specific regulatory element located approximately 6 kb upstream of the murine AP-2gamma gene transcription start site, and we have shown that Sp1 and Sp3 bind to cis-regulatory elements located in the promoter proximal region and contribute to basal promoter activity.

5' Flanking Region↗
PubMed2003

111In-DOTA- dPhe1-Tyr3-octreotide, 111In-DOTA-lanreotide and 67Ga citrate scintigraphy for visualisation of extranodal marginal zone B-cell lymphoma of the MALT type: a comparative study.

Somatostatin receptor (SSTR) scintigraphy and gallium-67 citrate ((67)Ga) scintigraphy have been used for visualisation of Hodgkin's lymphoma and non-Hodgkin's lymphoma. However, experience with B-cell lymphoma of the mucosa-associated lymphoid tissue (MALT) type is very limited. The aim of this study was to prospectively compare the (67)Ga scintigraphy results with those obtained by (111)In-DOTA- dPhe(1)-Tyr(3)-octreotide ((111)In-DOTA-TOCT) and (111)In-DOTA-lanreotide ((111)In-DOTA-LAN) scintigraphy in patients with proven MALT-type lymphoma. Comparative scintigraphic examinations using (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN were performed in 18 patients (11 female and 7 male, median age 64+/-15 years) with histologically verified MALT-type lymphomas of various origin. Planar and single-photon emission tomography imaging acquisitions were performed after injection of a mean dose of 185+/-26 MBq (67)Ga and 165+/-20 MBq (111)In-DOTA-TOCT or (111)In-DOTA-LAN. All scintigraphic results were correlated with other conventional examinations including gastroscopy, colonoscopy, endosonoscopy, ophthalmologic investigation, CT of the thorax and abdomen and bone marrow biopsy. This comparative study showed that (67)Ga scintigraphy found abnormalities in 10 of 16 patients (63%) and detected 18 of 31 clinically involved sites (58%), but was false positive in three patients. (111)In-DOTA-TOCT found abnormalities in 9 of 15 patients (60%) and detected 15 of 27 clinical lesions (56%); it was false positive in two patients. (111)In-DOTA-LAN scintigraphy showed abnormalities in 7 of 11 patients (64%) and found 12 of 22 clinical lesions (55%). False-positive (111)In-DOTA-LAN scan results were found in two patients. For supra-diaphragmatic lesions, (67)Ga scintigraphy detected 12 of 16 sites (75%). (111)In-DOTA-TOCT scintigraphy revealed 7 of 15 lesions (47%). (111)In-DOTA-LAN showed 6 of 12 positive sites (50%). For infra-diaphragmatic involvement, the sensitivities of (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN were 40%, 67% and 60%, respectively. It is concluded that MALT-type lymphoma can be visualised by (67)Ga, (111)In-DOTA-TOCT and (111)In-DOTA-LAN scintigraphy. Although there were no statistically significant differences in patient-related and site-related sensitivities when using (67)Ga compared with (111)In-DOTA-TOCT and (111)In-DOTA-LAN, the sensitivity of (67)Ga tended to be superior to that of (111)In-DOTA-TOCT and (111)In-DOTA-LAN for supra-diaphragmatic lesions but inferior for infra-diaphragmatic involvement. In selected cases, the combination of (67)Ga and (111)In-DOTA-LAN or (111)In-DOTA-TOCT may increase the diagnostic efficiency in patients with MALT-type lymphoma.

Adult↗
PubMed2003

[HLA-DRB and -DQB allele contribution to narcolepsy susceptibility in Chinese patients with narcolepsy].

OBJECTIVES: To study the association of narcolepsy with HLA class II alleles in Chinese narcoleptic patients. METHODS: 31 patients with narcolepsy underwent brain computed tomography (CT) scan and magnetic resonance imaging (MRI) testing. All patients received a MSLT test following a routine night's sleep, and serological HLA typing for HLA DR(2). 21 patients received PCR-SSP HLA DR and DQ typing. RESULTS: All patients had sleepiness and cataplexy. There was no evidence for other functional or structural diseases. Sleep paralysis was elicited in 45%; hypnagogic hallucinations, in 61%. Mean sleep latency on MSLT was 2.1 min +/- 1.3 min; sleep-onset rapid eye movement (SOREM) occurred during 2/5 naps in 30 of 31 patients. The average number and latency of SOREM episodes were 4.2 +/- 1.0 episodes and 4.0 min +/- 1.8 min, respectively. All patients but one were HLA DR(2) positive and 86% were HLADRB(1) * 1501-HLADQB(1)*0602 positive. CONCLUSIONS: HLA DR(2) and HLADQw6 are markers for narcolepsy-cataplexy in Chinese.

Adolescent↗
PubMed2003

Deletion of the P2X7 nucleotide receptor reveals its regulatory roles in bone formation and resorption.

The P2X7 nucleotide receptor is an ATP-gated ion channel expressed widely in cells of hematopoietic origin. Our purpose was to explore the involvement of the P2X7 receptor in bone development and remodeling by characterizing the phenotype of mice genetically modified to disrupt the P2X7 receptor [knockout (KO)]. Femoral length did not differ between KO and wild-type (WT) littermates at 2 or 9 months of age, indicating that the P2X7 receptor does not regulate longitudinal bone growth. However, KO mice displayed significant reduction in total and cortical bone content and periosteal circumference in femurs, and reduced periosteal bone formation and increased trabecular bone resorption in tibias. Patch clamp recording confirmed expression of functional P2X7 receptors in osteoclasts from WT but not KO mice. Osteoclasts were present in vivo and formed in cultures of bone marrow from KO mice, indicating that this receptor is not essential for fusion of osteoclast precursors. Functional P2X7 receptors were also found in osteoblasts from WT but not KO mice, suggesting a direct role in bone formation. P2X7 receptor KO mice demonstrate a unique skeletal phenotype that involves deficient periosteal bone formation together with excessive trabecular bone resorption. Thus, the P2X7 receptor represents a novel therapeutic target for the management of skeletal disorders such as osteoporosis.

Animals↗
PubMed2003

The second largest subunit of RNA polymerase II interacts with and enhances transactivation of androgen receptor.

AR may communicate with the general transcription machinery on the core promoter to exert its function as a transcriptional modulator. Our previous reports demonstrated that AR interacted with TFIIH and positive transcription elongation factor b (P-TEFb), and that phosphorylation of the carboxy-terminal domain in the largest subunit of RNA polymerase II might play important roles in AR-mediated transcription. These results suggest that AR may modulate gene expression by enhancing the efficiency of transcriptional elongation. Here we further demonstrate that co-expression of the second largest subunit of RNA polymerase II (RPB2) enhances AR transactivation. However, co-expression of the other subunits of RNA polymerase II or TFIIB did not show preferential enhancement of AR-mediated transcription. Furthermore, co-transfection of RPB2 with ER showed little effect on enhancement of ER transactivation. Together, AR may be able to interact with TFIIH, P-TEFb, and RPB2 to enhance transcription from AR target genes, such as prostate specific antigen that may play important roles in the prostate cancer progression.

Animals↗
PubMed2003

Evaluation of QIAamp DNA Stool Mini Kit for ecological studies of gut microbiota.

Cell lysis efficiency and the quality of DNA extracts from complex bacterial ecosystems are two major concerns in molecular ecological studies of gut microbiota. In this study, we use PCR-denaturing gradient gel electrophoresis (DGGE) DNA profiling, random cloning and sequence analysis of 16S rRNA genes to compare the QIAamp DNA Stool Mini Kit with the bead beating technique in the preparation of DNA extracts from gut microbiota of pigs. We also developed a washing procedure that can release more than 93% of bacterial cells attached to the gut mucosa. Both the QIAamp kit and bead beating method lysed approximately 95% of bacterial cells. PCR-DGGE DNA profiles of ileal and cecal microbiota from both digesta and mucosa that were generated from the DNA extracts using the two methods were nearly identical. Random cloning and sequence analysis also demonstrated the high quality of DNA extracts using the two methods. Two random clone sets of 16S rRNA genes generated from the DNA extracts had a similar degree of bacterial diversity. Different preparations of DNA extract from a single sample using the QIAamp kit consistently produced similar PCR-DGGE DNA profiles with similarity indexes higher than 99%. Our data suggest the appropriateness of the QIAamp DNA Stool Mini Kit for the studies of gut microbial ecology and the effectiveness of the QIAamp kit in processing multiple samples for cell lysis and DNA extraction.

Animals↗
PubMed2003

Early sensory information processes are enhanced on visual oddball and S1-S2 tasks in Parkinson's disease: a visual event-related potentials study.

To observe sensory and cognitive information processing in Parkinson's disease (PD), 34 PD patients and 26 controls were investigated. A visual oddball paradigm and an S1-S2 paradigm were employed to record the early (P1, N1, P2) and late (N2, P3) event-related potentials (ERPs) at Cz, Pz and Oz. Results showed: (1) enlarged P1 amplitude at all electrode locations on both tasks, (2) shortened N1 latency and enlarged P2 amplitude at Oz on both tasks, (3) enlarged N1 amplitude at Cz during an oddball paradigm, (4) delayed N2 latency and decreased N2, P3 amplitude on both tasks, and (5) delayed P3 latency and reaction time during the S1-S2 paradigm. Abnormal ERP changes were correlated with worsened scores on Wechsler Adult Intelligence Scale-Revised and motor dysfunction scales in PD. We surmise overactive aspects or failed inhibitory modulation of sensory information processing in the early ERP stage and deficient cognitive information processing during the late ERP stage in PD.

Adult↗
PubMed2003

Moderate-density molecular maps of Eucalyptus urophylla S. T. Blake and E. tereticornis Smith genomes based on RAPD markers.

Moderate-density molecular maps were constructed for the genomes of Eucalyptus urophylla S. T. Blake and E. tereticornis Smith using RAPD markers and an interspecific cross between the two species. One hundred and eighty-three primers were employed to generate 245 and 264 parent-specific markers in E. urophylla and E. tereticornis, respectively, as well as 49 parent-shared markers. The normally segregating markers, including 208 (84.9%) specific to maternal E. urophylla, 175 (66.3%) to paternal E. tereticornis, and 48 shared by both parents, were used for framework map construction for each parental species. For maternal E. urophylla, the linkage map consisted of 23 linkage groups, 160 framework markers, and 60 accessory markers, defining a total map distance of 1504.6cM and an average interval of 11.0 +/- 8.07 cM. For paternal E. tereticornis, the linkage map contained 23 linkage groups, 126 framework markers, and 92 accessory markers, defining a total map distance of 1035.7 cM and an average interval of 10.1 +/- 7.23 cM. Genome length was estimated at 1585.7 and 1507.5 cM for E. urophylla and E. tereticornis, respectively, indicating map coverage of 94.9 and 68.7% of the corresponding genomes. Construction of such maps will be valuable for quantitative trait loci (QTLs) detection, marker-assisted selection (MAS), comparative mapping, and whole genome based fingerprint characterization in Eucalyptus breeding programs.

Chromosome Mapping↗
PubMed2003

Purification, characterization and crystallization of a group of earthworm fibrinolytic enzymes from Eisenia fetida.

Seven fibrinolytic enzymes were purified from the earthworm Eisenia fetida. The molecular weights of the enzymes were 24663, 29516, 29690, 24201, 24170, 23028 and 29595, and the respective isoelectric points were 3.46, 3.5, 3.5, 3.68, 3.62, 3.94 and 3.46. All the proteases showed different fibrinolytic activity on fibrin plates. Studies on substrate specificity and inhibition indicated that they belonged to different types of serine proteases. N-Terminal sequencing indicated their high homology to those from the earthworm Lumbricus rubellus. All the enzymes have been crystallized.

Amino Acid Sequence↗
PubMed2003

Glycylproline dipeptidyl aminopeptidase isoenzyme in diagnosis of primary hepatocellular carcinoma.

AIM: To investigate the role of glycylproline dipeptidyl aminopeptidase (GPDA) isoenzyme in the diagnosis of primary hepatocellular carcinoma (PHC), especially in patients with negative alpha-fetoprotein (AFP). METHODS: A stage gradient polyacrylamide gel discontinuous electrophoresis system was developed to separate serum GPDA isoenzymes, which were determined in 102 patients with PHC, 45 cases with liver cirrhosis, 24 cases with chronic hepatitis, 35 cases with benign liver space-occupying lesions, 20 cases with metastatic liver cancer and 50 cases with extra-hepatic cancer, as well as 80 healthy subjects. The relationships between GPDA isoenzymes and AFP, the sizes of tumors, as well as alanine aminotransferase (ALT) were also analyzed. RESULTS: Serum GPDA was separated into two isoenzymes, GPDA-S and GPDA-F. The former was positive in all subjects, while the latter was found mainly in majority of PHC (85.3 %) and a few cases with liver cirrhosis (11.1 %), chronic hepatitis (33.3 %), metastatic liver cancer (15.0 %) and non-hepatic cancer (16.0 %). GPDA-F was negative in all healthy subjects and patients with benign liver space-occupying lesions, including abscess, cysts and angioma. There was no correlation between GPDA-F and AFP concentration or tumor size. GPDA-F was consistently positive and not correlated with ALT in PHC, but GPDA-F often converted to negative as decline of ALT in benign liver diseases. The electrophoretic migration of GPDA-F became sluggish after the treatment of neuraminidase. CONCLUSION: GPDA-F is a new useful serum marker for PHC. Measurement of serum GPDA-F is helpful in diagnosis of PHC, especially in patients with negative AFP. GPDA-F is one kind of glycoproteins rich in sialic acid.

Aminopeptidases↗
PubMed2003

Oral immunization of animals with transgenic cherry tomatillo expressing HBsAg.

AIM: To investigate the expression of recombinant HBsAg (rHBsAg) in transgenic cherry tomatillo in order to explore the feasibility of producing HBV oral vaccine with cherry tomatillo by animal immune tests. METHODS: The recombinant plant expression vector containing HBsAg gene was constructed. Mediated with Agrobacterium tumefaciens, HBsAg gene was transferred into cotyledons of cherry tomatillo. Transformed cherry tomatillos were obtained through hygromycin delay-selection. Integrated DNA in transgenic cherry tomatillo was confirmed by hygromycin resistance selection, Gus detection, polymerase chain reaction (PCR) and dot blotting analysis. Antigenicity of rHBsAg was examined by ELISA and the immunogenicity of rHBsAg derived from transgenic cherry tomatillo tissues was confirmed by oral feed of transformed tissues to BALB/c mice primed with commercial HBV vaccines. Specific antibody titers in mice's serum were examined by ELISA every week. RESULTS: By far, 10 positive lines of transgenic cherry tomatillos containing HBsAg gene were obtained. Among different organs of the same transgenic cherry tomatillo, level of rHBsAg expressed in leaves was the highest with the yield up to 300ng/g fresh weight. And the rHBsAg expression level in fruits was about 10 ng/g fresh weight. In animal immune tests, oral delivery with transgenic tissues to mice primed with commercial vaccine instead of naive mice resulted in significant immune response. CONCLUSION: The result of this animal immune test indicated the rHBsAg derived from transgenic cherry tomatillo possessed normal immunogenicity. This work demonstrated the feasibility to generate oral immunogenic rHBsAg in transgenic cherry tomatillo, and would provide some experimental approach for the production of low-cost oral vaccines using transgenic cherry tomatillo in large scale.

Administration, Oral↗
PubMed2003

[A study on the expression of VEGF in the blunt injury of rat's skin].

OBJECTIVE: To evaluate changes of VEGF in skin after blunt injury. METHODS: The rats of injury groups were subjected to skin blunt injury by free-falling iron hammer. The samples taken at 1 h, 3 h, 6 h, 12 h, 1 d, 3 d, 5 d, 7 d, 9 d after injury were studied by immunohistochemistry and MIAS image analysis system. RESULTS: In the skin of normal control group the expression level of VEGF was low. The increase of VEGF could be observed at 1 day after injury, reached peak at 7 days and declined at 9 days. CONCLUSION: Blunt injury in the skin could induce the expression of the VEGF. Moreover, the change pattern of VEGF level was quite regular with time and could be used to estimate the time after skin injury.

Animals↗