Biomedical subjects

Chunhui Zhou

Publications and source records attributed to Chunhui Zhou.

4 recordsLinked to original sources

PubMed2026

Efficacy and safety of microwave ablation for the treatment of pulmonary osteosarcoma oligometastases.

PURPOSE: Evaluate efficacy and safety of microwave ablation (MWA) for pulmonary osteosarcoma oligometastases. METHODS: Twenty-two patients (median age, 16 years [range, 9-41 years]; 15 male) with pulmonary osteosarcoma oligometastases who underwent MWA from January 2018 to December 2023 were included, with 27 MWA sessions for 36 lung metastases. Technical success and complications were evaluated in all 22 patients, while efficacy and survival were evaluated in 19 patients with 24 MWA sessions in treatment of 32 tumors. Technical success was assessed for each tumor. Local tumor control, progression-free survival (PFS) and overall survival (OS) were estimated using Kaplan-Meier method. Complications were classified using Common Terminology Criteria for Adverse Events version 5.0. RESULTS: Technical success was achieved in all 36 tumors (100.0%). Local tumor progression occurred in five of 32 tumors (15.6%). The estimated local tumor control rates at 12, 24 and 36 months were 96.9%, 86.1% and 81.5%, respectively. No significant difference in local control was found between tumors ≤ 10 mm and > 10 mm (p = .470). Twelve of 19 patients (63.2%) developed new lung metastases outside the ablation area, including one with concurrent newly developed bone metastases and one with recurrence of primary osteosarcoma. The median PFS was 21.5 months. The estimated OS rates at 12, 24 and 60 months were 100.0%, 94.4% and 94.4%, respectively. Major complications occurred in five of 27 sessions (18.5%). CONCLUSIONS: MWA preliminarily demonstrates a high technical success rate, notable local tumor control, promising overall survival and acceptable safety for pulmonary osteosarcoma oligometastases.

Adolescent↗

PubMed2006

Length effects in antimicrobial peptides of the (RW)n series.

A class of antimicrobial peptides involved in host defense consists of sequences rich in Arg and Trp-R and -W. Analysis of the pharmacophore in these peptides revealed that chains as short as trimers of sequences such as WRW and RWR have antimicrobial activity (M. B. Strom, B. E. Haug, M. L. Skar, W. Stensen, T. Stiberg, and J. S. Svendsen, J. Med. Chem. 46:1567-1570, 2003). To evaluate the effect of chain length on antimicrobial activity, we synthesized a series of peptides containing simple sequence repeats, (RW)n-NH2 (where n equals 1, 2, 3, 4, or 5), and determined their antimicrobial and hemolytic activity. The antimicrobial activity of the peptides increases with chain length, as does the hemolysis of red blood cells. Within the experimental error, longer peptides (n equals 3, 4, or 5) show similar values for the ratio of hemolytic activity to antibacterial activity, or the hemolytic index. The (RW)3 represents the optimal chain length in terms of the efficacy of synthesis and selectivity as evaluated by the hemolytic index. Circular dichroism spectroscopy indicates that these short peptides appear to be unfolded in aqueous solution but acquire structure in the presence of phospholipids. Interaction of the peptides with model lipid vesicles was examined using tryptophan fluorescence. The (RW)n peptides preferentially interact with bilayers containing the negatively charged headgroup phosphatidylglycerol relative to those containing a zwitterionic headgroup, phosphatidylcholine.

Amino Acid Sequence↗

PubMed2006

Multivalent antimicrobial peptides from a reactive polymer scaffold.

We report an application of the principle of multivalency to create new antimicrobial agents using the reactive polymaleic anhydride (PMA) chain to link antimicrobial tetrapeptides to afford multivalent variants containing approximately 40 monomer units. Relative to the free peptides, the product shows a 10-fold improvement in IC(50) without provoking more severe hemolysis of red blood cells. Thus, multivalency or polyvalency may offer a route to enhance the activity of antimicrobial peptides.

Anti-Infective Agents↗

PubMed2005

Neighbor effect on PPII conformation in alanine peptides.

The polyproline II (PPII) conformation is dominant in short alanine oligomers. The noncooperativity of PPII structure in alanine peptides indicates that PPII in water is locally determined and that alanine neighbors are consistent with Flory's isolated pair hypothesis. However, neighbor effects from beta-branched or bulky aromatic residues tend to increase the Phi angle of the nearest neighbor as observed in coil library data. Here we demonstrate directly the neighbor effect using short alanine model peptides GGAAAGG, GGLnALnGG (Ln is norleucine), GGIAAGG, and GGIAIGG. The far-UV CD spectra, NMR 3JalphaN coupling constant, and H-D hydrogen exchange measurements reveal that Ile reduces the PPII content of the probe Ala side chain relative to Ala or norLeu. The free energy differences are consistent with predictions from electrostatic solvation free energy (ESF) calculations. The results indicate that prediction of PPII propensities or scales requires including the neighbor effect.

Alanine↗