Amide proton transfer-weighted MRI for assessing rectal adenocarcinoma T-staging and perineural invasion: a prospective study.

OBJECTIVE: To investigate the value of the pre-operative amide proton transfer-weighted (APTw) MRI to assess the prognostic factors in rectal adenocarcinoma (RA). METHODS: This prospective study ran from January 2022 to September 2023 and consecutively enrolled participants with RA who underwent pre-operative MRI and radical surgery. The APTw signal intensity (SI) values of RA with various tumor (T), node (N) stages, perineural invasion (PNI), and tumor grade were compared by Mann-Whitney U-test or t-test. The receiver operating characteristic curve was used to evaluate the diagnostic performance of the APTw SI values. RESULTS: A total of 51 participants were enrolled (mean age, 58 years ± 10 [standard deviation], 26 men). There were 24 in the T1-T2 stage and 9 with positive PNI. The APTw SI max, 99th, and 95th values were significantly higher in T3-T4 stage tumor than in T1-T2; the median (interquartile range) (M (IQR)) was (4.0% (3.6-4.9%) vs 3.4% (2.9- 4.3%), p = 0.017), (3.7% (3.2-4.1%) vs 3.2% (2.8-3.8%), p = 0.013), and (3.3% (2.8-3.8%) vs 2.9% (2.3-3.5%), p = 0.033), respectively. These indicators also differed significantly between the PNI groups, with the M (IQR) (4.5% (3.6-5.7%) vs 3.7% (3.2-4.2%), p = 0.017), (4.1% (3.4-4.8%) vs 3.3% (3.0-3.9%), p = 0.022), and (3.7% (2.7-4.2%) vs 2.9% (2.6-3.5%), p = 0.045), respectively. CONCLUSION: Pre-operative APTw MRI has potential value in the assessment of T-staging and PNI determination in RA. CLINICAL RELEVANCE STATEMENT: Pre-operative amide proton transfer-weighted MRI provides a quantitative method for noninvasive assessment of T-staging and PNI in RA aiding in precision treatment planning. KEY POINTS: The efficacy of APTw MRI in RA needs further investigation. T3-T4 stage and PNI positive APTw signal intensities were higher than T1-T2 and non-PNI, respectively. APTw MRI provides a quantitative method for assessment of T staging and PNI in RA.

Semiquantitative assessment of optic nerve injury using manganese-enhanced MRI.

OBJECTIVE: To evaluate the capability of manganese (Mn(2+))-enhanced MRI (MEMRI) in a continuously semiquantitative assessment of rat optic nerve (ON) injury. METHODS: Forty rats were divided into three groups: (I) a control group that was submitted to MEMRI or to fluorescent labeling of retinal ganglion cells (RGCs) (n = 10); (II) an ON injury group that was submitted to MEMRI (n = 15); (III) an ON injury group that was submitted to fluorescent labeling of RGCs (n = 15). Groups II and III were examined at 3, 7, and 14 days post-lesion (dpl), when the contrast-to-noise ratio (CNR) of the retina and ON was measured on MEMRI images and the RGCs were counted by fluorescence microscopy and compared between the groups. RESULTS: In the control group, the intact visual pathway from the retina to the contralateral superior colliculus was visualized by MEMRI. In group II, continuous Mn(2+) enhancement was seen from the retina to the lesion site of the optic nerves at 3, 7, and 14 dpl. However, no Mn(2+) enhancement was observed distal to the lesion site at those time points. The observed Mn(2+) enhancement proximal to the ON lesion site declined between 7 and 14 dpl. The decrease in Mn(2+)-enhanced signal intensity at these sites at 7 and 14 dpl when compared to that at 3 dpl was significant (P < 0.05). The RGC density dropped by 6.84, 45.31, and 72.36 % at 3, 7, and 14 dpl, respectively. CONCLUSION: MEMRI can be used to evaluate the structural changes after optic nerve injury.

The CT and US features of Ewing's sarcoma/primary neuroectodermal tumor of the kidney: two case reports and review of literature.

Ewing's sarcoma/primary neuroectodermal tumor (EWS/PNET) is an extraordinarily rare primary tumor of the kidney with characteristic histology. To date, the imaging features of EWS/PNET have not been clearly described. Here, we report two cases of EWS/PNET confirmed by fine-needle aspiration biopsy and analyze the findings of computed tomography and ultrasound. The radiological features of EWS/PNET are presented along with a brief review of the pertinent literature to have a further understanding of EWS/PNET's imaging features.

Genome-wide profiling of chemoradiation­induced changes in alternative splicing in colon cancer cells.

Alternative splicing is a key mechanism that regulates protein diversity and has been found to be associated with colon cancer progression and metastasis. However, the function of alternative splicing in chemoradiation­resistant colon cancer remains elusive. In this study, we constructed a chemoradiation­resistant colon cancer cell line. Through RNA-sequencing of normal and chemoradiation­resistant colon cancer cells (HCT116), we found 818 genes that were highly expressed in the normal HCT116 cells, whereas 285 genes were highly expressed in the chemoradiation-resistant HCT116 (RCR-HCT116) cells. Gene ontology (GO) analysis showed that genes that were highly expressed in the HCT116 cells were enriched in GO categories related to cell cycle and cell division, whereas genes that were highly expressed in the RCR-HCT116 cells were associated with regulation of system processes and response to wounding. Analysis of alternative splicing events revealed that exon skipping was significantly increased in the chemoradiation­resistant colon cancer cells. Moreover, we identified 323 alternative splicing events in 293 genes that were significantly different between the two different HCT116 cell types. These alternative splicing­related genes were clustered functionally into several groups related with DNA replication, such as deoxyribonucleotide metabolic/catabolic processes, response to DNA damage stimulus and helicase activity. These findings enriched our knowledge by elucidating the function of alternative splicing in chemoradiation-resistant colon cancer.

Potential Use of Antimicrobial Peptides as Vaginal Spermicides/Microbicides.

The concurrent increases in global population and sexually transmitted infection (STI) demand a search for agents with dual spermicidal and microbicidal properties for topical vaginal application. Previous attempts to develop the surfactant spermicide, nonoxynol-9 (N-9), into a vaginal microbicide were unsuccessful largely due to its inefficiency to kill microbes. Furthermore, N-9 causes damage to the vaginal epithelium, thus accelerating microbes to enter the women's body. For this reason, antimicrobial peptides (AMPs), naturally secreted by all forms of life as part of innate immunity, deserve evaluation for their potential spermicidal effects. To date, twelve spermicidal AMPs have been described including LL-37, magainin 2 and nisin A. Human cathelicidin LL-37 is the most promising spermicidal AMP to be further developed for vaginal use for the following reasons. First, it is a human AMP naturally produced in the vagina after intercourse. Second, LL-37 exerts microbicidal effects to numerous microbes including those that cause STI. Third, its cytotoxicity is selective to sperm and not to the female reproductive tract. Furthermore, the spermicidal effects of LL-37 have been demonstrated in vivo in mice. Therefore, the availability of LL-37 as a vaginal spermicide/microbicide will empower women for self-protection against unwanted pregnancies and STI.