Exome and Tissue-Associated Microbiota as Predictive Markers of Response to Neoadjuvant Treatment in Locally Advanced Rectal Cancer.

The clinical and pathological responses to multimodal neoadjuvant therapy in locally advanced rectal cancers (LARCs) remain unpredictable, and robust biomarkers are still lacking. Recent studies have shown that tumors present somatic molecular alterations related to better treatment response, and it is also clear that tumor-associated bacteria are modulators of chemotherapy and immunotherapy efficacy, therefore having implications for long-term survivorship and a good potential as the biomarkers of outcome. Here, we performed whole exome sequencing and 16S ribosomal RNA (rRNA) amplicon sequencing from 44 pre-treatment LARC biopsies from Argentinian and Brazilian patients, treated with neoadjuvant chemoradiotherapy or total neoadjuvant treatment, searching for predictive biomarkers of response (responders, = 17; non-responders, = 27).

Evaluation of Bacteria and Fungi DNA Abundance in Human Tissues.

Whereas targeted and shotgun sequencing approaches are both powerful in allowing the study of tissue-associated microbiota, the human: microorganism abundance ratios in tissues of interest will ultimately determine the most suitable sequencing approach. In addition, it is possible that the knowledge of the relative abundance of bacteria and fungi during a treatment course or in pathological conditions can be relevant in many medical conditions. Here, we present a qPCR-targeted approach to determine the absolute and relative amounts of bacteria and fungi and demonstrate their relative DNA abundance in nine different human tissue types for a total of 87 samples.

Influence of biomaterials on scintigraphic diagnosis of periprosthetic infections. Ceftizoxime-99m technetium model.

Purpose: To compare the influence of two metallic implants in the diagnosis of periprosthetic infection using 99m technetium-labeled ceftizoxime.

Methods: Twenty rats were randomly divided into four groups, which received sterile and contaminated titanium and stainless steel implants. After 3 weeks, scintilographic images were obtained using a gamma chamber.

Scintigraphic imaging with technetium-99M-labelled ceftizoxime is a reliable technique for the diagnosis of deep sternal wound infection in rats.

Purpose: To evaluate whether scintigraphy with technetium-99m-labeled ceftizoxime ((99m)Tc-CFT) can differentiate mediastinitis from aseptic inflammation associated with sternotomy.

Methods: Twenty female Wistar rats were randomly distributed into four groups: S (control) -partial upper median sternotomy with no treatment; SW (control) - sternotomy and treatment of sternal wounds with bone wax; SB - sternotomy and infection with Staphylococcus aureus; SWB - sternotomy with bone wax treatment and bacterial infection. Scintigraphy with (99m)Tc-CFT was performed eight days after surgery and images were collected 210 and 360 min after infusion of the radiopharmaceutical.

Efficacy of (99m)Tc-Labeled Ceftizoxime in the Diagnosis of Subclinical Infections Associated with Titanium Implants in Rats.

Background: Metal implants are used frequently in orthopedic procedures and the occurrence of subclinical low-virulence infection is difficult to diagnose. The objective of this study was to examine the hypothesis that peri-prosthetic subclinical infections may be diagnosed effectively in a murine model system using scintigraphic imaging with (99m)Tc-labeled ceftizoxime.

Methods: A sample population of 3-mo old Wistar rats (mean weight 327 g) was divided randomly into a control group (n=6), which received sterile implants, and an experimental group (n=6), which received implants contaminated with Staphylococcus aureus strain ATCC6538-P.