Biomedical subjects

Pan Wang

Publications and source records attributed to Pan Wang.

4 recordsLinked to original sources

PubMed2026

A Molecularly Anchored Spatial Transcriptomic Framework for Precise CA1-Subiculum Parcellation and Region-Resolved Analysis in Alzheimer's Disease.

BACKGROUND: The precise molecular delineation of the interface between the Subiculum (Sub) and cornu ammonis 1 (CA1) is a challenge in hippocampal research, as conventional cytoarchitectural boundaries are often ambiguous and limit reproducible regional annotation. Here, we developed a molecularly anchored spatial transcriptomic framework to define CA1-Sub regional identities using high-definition spatial transcriptomics (Stereo-seq) and single-nucleus RNA sequencing (snRNA-seq) references. FINDINGS: Using a human hippocampal Stereo-seq dataset from 12 donors, we established a data-driven parcellation framework that defines reproducible molecular features distinguishing CA1 and Sub while capturing the transition between these regions. FN1 was identified as a Sub-enriched marker in a subset of EX_Sub and, together with ETV1 and additional regional markers, enabled molecular assignment of CA1 and Sub identities across datasets. The Sub association of FN1 and ETV1 was further supported by human 10X Genomics spatial transcriptomics, mouse in situ hybridization data, and a mouse spatial transcriptomic dataset. Applying this framework to Alzheimer's disease (AD) tissues revealed region-specific transcriptional alterations across CA1 and Sub, including enrichment of mitochondrial energy metabolism-related transcripts in the Sub, suggesting exploratory transcriptional associations of altered metabolic function. CONCLUSIONS: This study provides a molecularly anchored framework for human CA1-Sub parcellation that complements conventional annotation. By defining regional molecular states while preserving the biological continuum across CA1-Sub interface, this approach enables more consistent regional analysis of human hippocampus tissue across donors, datasets, and disease conditions.

Journal Article↗

PubMed2007

Comparison between sonodynamic effect with protoporphyrin IX and hematoporphyrin on sarcoma 180.

PURPOSE: The comparison between sonodynamic antitumor effect with protoporphyrin IX (PPIX) and hematoporphyrin (Hp) at a concentration of 5 mg/kg on Sarcoma 180 (S180) cells was studied in vivo, and the potential cell damage mechanism was also investigated. METHODS: The sonodynamically induced anti-tumor effect of PPIX was studied in mice bearing S180 solid tumors. In order to determine the optimum timing of ultrasound exposure after administration of PPIX, the PPIX concentrations in plasma, skin, muscle and tumor were determined by the fluorescence intensity of tissue extractions with a fluorescence spectrophotometer based on the standard curve. Anti-tumor effects were estimated by measuring the tumor size and the tumor weight. Additionally, the morphological changes of S180 cells were evaluated by transmission electron microscope (TEM) observation immediately after sonodynamic therapy (SDT) treatment. RESULTS: A time of 24 h after the intravenous administration of PPIX was chosen as the best time for ultrasound exposure. The antitumor effect induced by PPIX mediated sonodynamic therapy (PPIX-SDT) was in a dose dependent manner when ultrasound intensity was at or above the inertial cavitation threshold (5 W/cm(2)). A significant tumor growth delay was observed both in PPIX mediated sonodynamic therapy and in Hp mediated sonodynamic therapy treatments (Hp-SDT), and the tumor weight inhibition ratios after the synergistic treatments were 42.82 +/- 0.03 and 35.22 +/- 0.03%, respectively, this difference was significant at P < 0.05. While ultrasound alone (5 W/cm(2)) showed a slight tumor growth inhibitory effect compared with the control group, and PPIX or Hp alone showed almost no significant effect. Furthermore, TEM observation indicated cell damage was more serious in PPIX-SDT treatment group than in Hp-SDT treatment group. After sonication, the cell ultra-structure such as cell membrane destruction, mitochondria swelling, chromatin condensation might be important factors that inhibited the tumor growth and even induced cell death. CONCLUSIONS: The comparative results suggested that PPIX as a sonosensitizer might have more potential cytotoxicity than Hp when irradiated with ultrasound, and the ultra-structural changes may account for cell destruction induced by sonodynamic therapy in our experiment mode.

Animals↗

PubMed2006

Sonodynamic effects of protoporphyrin IX disodium salt on isolated sarcoma 180 cells.

The cytotoxic effect of PPIX on isolated sarcoma 180 cells induced by ultrasound was investigated. Tumor cells suspended in air-saturated PBS (pH 7.2) were exposed to ultrasound at 2.2 MHz for up to 60s in the presence and absence of protoporphyrin IX disodium salt (PPIX). The viability of cells was determined by a trypan blue exclusion test. The rate of ultrasonically induced cell damage was increased with 40-160 microM PPIX, while no cell damage was observed with 160 microM PPIX alone. This enhancement of cell damage with PPIX was inhibited by histidine. The participation of lipid peroxidation products in the cell damage process was also investigated. Scanning electron microscope (SEM) observation of the surface of cells was performed to evaluate the morphological changes induced by ultrasonic irradiation. The results indicate the involvement of a sonochemical mechanism.

Animals↗

PubMed2005

Determination of the metal ion dependence and substrate specificity of a hydratase involved in the degradation pathway of biphenyl/chlorobiphenyl.

BphH is a divalent metal ion-dependent hydratase that catalyzes the formation of 2-keto-4-hydroxypentanoate from 2-hydroxypent-2,4-dienoate (HPDA). This reaction lies on the catabolic pathway of numerous aromatics, including the significant environmental pollutant, polychlorinated biphenyls (PCBs). BphH from the PCB degrading bacterium, Burkholderia xenoverans LB400, was overexpressed and purified to homogeneity. Atomic absorption spectroscopy and Scatchard analysis reveal that only one divalent metal ion is bound to each enzyme subunit. The enzyme exhibits the highest activity when Mg2+ was used as cofactor. Other divalent cations activate the enzyme in the following order of effectiveness: Mg2+ > Mn2+ > Co2+ > Zn2+ > Ca2+. This differs from the metal activation profile of the homologous hydratase, MhpD. UV-visible spectroscopy of the Co2+-BphH complex indicates that the divalent metal ion is hexa-coordinated in the enzyme. The nature of the metal ion affected only the kcat and not the Km values in the BphH hydration of HPDA, suggesting that cation has a catalytic rather than just a substrate binding role. BphH is able to transform alternative substrates substituted with methyl- and chlorine groups at the 5-position of HPDA. The specificity constants (kcat/Km) for 5-methyl and 5-chloro substrates are, however, lowered by eight- and 67-fold compared with the unsubstituted substrate. Significantly, kcat for the chloro-substituted substrate is eightfold lower compared with the methyl-substituted substrate, showing that electron withdrawing substituent at the 5-position of the substrate has a negative influence on enzyme catalysis.

Bacterial Proteins↗