Comparisons of pathologic findings and outcomes of gastric cancer patients younger and older than 40: a propensity score matching study in a single center of Korea.

Background and Aim: Gastric cancer (GC) is one of the most common cancers worldwide, with a high incidence rate in Korean men. However, comparative studies are scarce on the pathologic findings and treatment effects of GC in patients aged less than 40 years. We evaluated the characteristics and pathologic findings of GC patients aged younger and older than 40 years. Methods: We retrospectively analyzed 2307 patients diagnosed with GC between January 2010 and May 2018. Eighty-eight (3.8%) and 2219 (96.2%) patients were younger and older than 40 years, respectively. The patients were divided into younger (n = 70) and older (n = 62) age groups through propensity matching. Results: Overall, compared to the younger group, the older group (n = 2219) had a significantly higher proportion of male patients (66.7% vs 39.8%; P < 0.001) and patients who underwent endoscopic submucosal dissection (ESD) (2.3% vs 23.1%; P < 0.001). However, young patients more often underwent operations compared to older patients (78.4% vs 60.1%; P = 0.001). In the propensity-matched group, older patients more often showed differentiated carcinoma, including well-differentiated (5.7% vs 11.3%) and moderately differentiated (1.4% vs 32.3%). However, younger patients more often showed signet ring cell carcinoma (SRC) (70.0% vs 25.8%). In multivariate analysis, Helicobacter pylori infection (odds ratio, 12.643; 95% confidence interval, 1.068-1449.665; P = 0.044) independently correlated with SRC risk. Conclusions: Patients below 40 years were more likely to undergo surgery compared to ESD, and pathologic findings were more common in SRC. Therefore, more active screening and H. pylori eradication are needed even in patients aged less than 40 years.

Purification, crystallization and preliminary X-ray diffraction analysis of enoyl-acyl carrier protein reductase (FabK) from Streptococcus mutans strain UA159.

A triclosan-resistant flavoprotein termed FabK is the sole enoyl-acyl carrier protein reductase in Streptococcus pneumoniae and Streptococcus mutans. In this study, FabK from S. mutans strain UA159 was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.40 Å resolution using a synchrotron-radiation source. The crystal belonged to space group P6(2), with unit-cell parameters a = b = 105.79, c = 44.15 Å. The asymmetric unit contained one molecule, with a corresponding V(M) of 2.05 Å(3) Da(-1) and a solvent content of 39.9%.

Overexpression, crystallization and preliminary X-ray crystallographic analysis of the RNA polymerase domain of primase from Streptococcus mutans strain UA159.

Primase is the enzyme that synthesizes RNA primers on single-stranded DNA during normal DNA replication. In this study, the catalytic core domain of primase from Streptococcus mutans UA159 was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 1.60 Å resolution using a synchrotron-radiation source. The crystal belonged to space group P4(1) or P4(3), with unit-cell parameters a = b = 52.63, c = 110.31 Å. The asymmetric unit is likely to contain one molecule, with a corresponding V(M) of 1.77 Å(3) Da(-1) and a solvent content of 30.7%.

Overexpression, purification, crystallization and preliminary X-ray crystallographic analysis of the C-terminal domain of the GyrA subunit of DNA gyrase from Staphylococcus aureus strain Mu50.

DNA gyrase is a type II topoisomerase that is essential for chromosome segregation and cell division owing to its ability to modify the topological form of bacterial DNA. In this study, the C-terminal domain of the GyrA subunit of DNA gyrase from Staphylococcus aureus Mu50 strain was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.80 Šresolution using a synchrotron-radiation source. The crystal belonged to space group P2(1), with unit-cell parameters a = 37.28, b = 80.19, c = 50.22 Å, ß = 110.64°. The asymmetric unit contained one molecule, with a corresponding V(M) of 2.02 Å(3) Da(-1) and a solvent content of 39.2%.

Cloning, purification, crystallization and preliminary X-ray crystallographic analysis of the N-terminal domain of DEAD-box RNA helicase from Staphylococcus aureus strain Mu50.

DEAD-box helicases are enzymes with an ATP-dependent RNA-unwinding function that are involved in a variety of cellular processes including RNA splicing, ribosome biogenesis and RNA degradation. In this study, the N-terminal domain of DEAD-box RNA helicase from Staphylococcus aureus strain Mu50 was overexpressed in Escherichia coli, purified and crystallized. Diffraction data were collected to 2.60 Šresolution using a synchrotron-radiation source. The crystal belonged to space group P1, with unit-cell parameters a=70.81, b=80.23, c=86.25 Å, α=69.54, ß=66.54, γ=87.32°. The unit cell contained six molecules, with a corresponding VM of 2.91 Å3 Da(-1) and a solvent content of 56.1%.