Profiling of 1-aminocyclopropane-1-carboxylic acid and selected phytohormones in Arabidopsis using liquid chromatography-tandem mass spectrometry.

BACKGROUND: Gaseous phytohormone ethylene levels are directly influenced by the production of its immediate non-volatile precursor 1-aminocyclopropane-1-carboxylic acid (ACC). Owing to the strongly acidic character of the ACC molecule, its quantification has been difficult to perform. Here, we present a simple and straightforward validated method for accurate quantification of not only ACC levels, but also major members of other important phytohormonal classes - auxins, cytokinins, jasmonic acid, abscisic acid and salicylic acid from the same biological sample. RESULTS: The presented technique facilitates the analysis of 15 compounds by liquid chromatography coupled with tandem mass spectrometry. It was optimized and validated for 10 mg of fresh weight plant material. The extraction procedure is composed of a minimal amount of necessary steps. Accuracy and precision were the basis for evaluating the method, together with process efficiency, recovery and matrix effects as validation parameters. The examined compounds comprise important groups of phytohormones, their active forms and some of their metabolites, including six cytokinins, four auxins, two jasmonates, abscisic acid, salicylic acid and 1-aminocyclopropane-1-carboxylic acid. The resulting method was used to examine their contents in selected Arabidopsis thaliana mutant lines. CONCLUSION: This profiling method enables a very straightforward approach for indirect ethylene study and explores how it interacts, based on content levels, with other phytohormonal groups in plants.

In situ separation and visualization of isomeric auxin derivatives in Arabidopsis by ion mobility mass spectrometry imaging.

In situ separation and visualization of synthetic and naturally occurring isomers from heterogeneous plant tissues, especially when they share similar molecular structures, are a challenging task. In this study, we combined the ion mobility separation with desorption electrospray ionization mass spectrometry imaging (DESI-IM-MSI) to achieve a direct separation and visualization of two synthetic auxin derivatives, auxinole and its structural isomer 4pTb-MeIAA, as well as endogenous auxins from Arabidopsis samples. Distinct distribution of these synthetic isomers and endogenous auxins in Arabidopsis primary roots and hypocotyls was achieved in the same imaging analysis from both individually treated and cotreated samples. We also observed putative metabolites of synthetic auxin derivatives, i.e. auxinole amino acid conjugates and hydrolysed 4pTb-MeIAA product - 4pTb-IAA, based on their unique drifting ion intensity patterns. Furthermore, DESI-IM-MSI-revealed abundance of endogenous auxins and synthetic isomers was validated by liquid chromatography-mass spectrometry (LC-MS). Our results demonstrate that DESI-IM-MSI could be used as a robust technique for detecting endogenous and exogenous isomers and provide a spatiotemporal evaluation of hormonomics profiles in plants.

Metabolic profiles of 2-oxindole-3-acetyl-amino acid conjugates differ in various plant species.

Auxins are a group of phytohormones that play a key role in plant growth and development, mainly presented by the major member of the family - indole-3-acetic acid (IAA). The levels of free IAA are regulated, in addition to de novo biosynthesis, by irreversible oxidative catabolism and reversible conjugation with sugars and amino acids. These conjugates, which serve as inactive storage forms of auxin and/or degradation intermediates, can also be oxidized to form 2-oxindole-3-acetyl-1-O-ß-d-glucose (oxIAA-glc) and oxIAA-amino acids (oxIAA-AAs). Until now, only oxIAA conjugates with aspartate and glutamate have been identified in plants. However, detailed information on the endogenous levels of these and other putative oxIAA-amino acid conjugates in various plant species and their spatial distribution is still not well understood but is finally getting more attention. Herein, we identified and characterized two novel naturally occurring auxin metabolites in plants, namely oxIAA-leucine (oxIAA-Leu) and oxIAA-phenylalanine (oxIAA-Phe). Subsequently, a new liquid chromatography-tandem mass spectrometry method was developed for the determination of a wide range of IAA metabolites. Using this methodology, the quantitative determination of IAA metabolites including newly characterized oxIAA conjugates in roots, shoots and cotyledons of four selected plant models - Arabidopsis thaliana, pea (Pisum sativum L.), wheat (Triticum aestivum L.) and maize (Zea mays L.) was performed to compare auxin metabolite profiles. The distribution of various groups of auxin metabolites differed notably among the studied species as well as their sections. For example, oxIAA-AA conjugates were the major metabolites found in pea, while oxIAA-glc dominated in Arabidopsis. We further compared IAA metabolite levels in plants harvested at different growth stages to monitor the dynamics of IAA metabolite profiles during early seedling development. In general, our results show a great diversity of auxin inactivation pathways among angiosperm plants. We believe that our findings will greatly contribute to a better understanding of IAA homeostasis.

Diagnostic challenges and treatment options in patients with solitary fibrous tumor: A single-center observational study.

Introduction: Solitary fibrous tumor (SFT) is an extremely rare disease with a high misdiagnosis rate and a potentially malignant biologic nature. We have collected and analyzed data from 18 SFT patients to provide a deeper insight into this uncommon disease entity. Methods: In our study, 18 patients who had undergone surgery between April 2014 and December 2021 for the diagnosis of SFT were evaluated. The collected data for each patient included the location of the SFT, the preoperative diagnosis, the definitive histological diagnosis, the presence of postoperative complications, the time of recurrence, the time of systemic progression, the type of treatment, and the survival rate. The median follow-up was 36 months. Results: In three patients, the preoperative diagnosis did not correlate with the definitive histology of SFT. In patients with the limb location of SFT, no signs of recurrence nor distant metastases were seen within the study period. In total, 50% of the postsurgical complications were associated with the abdominal location of the SFT. In newly diagnosed SFT patients, two patients (20%) developed local recurrence, and the median time until recurrence was 22.5 months. Out of patients that were admitted and operated on for recurrent SFT, 67% relapsed, and the median time to relapse was 9.5 months. The systemic progression of the disease was observed in 33% of patients treated for recurrent SFT. Conclusion: In our study, the misdiagnosis rate was high and correlated with previously published studies. Postsurgical complications were associated with the extrathoracic location of SFT. The mainstay of SFT treatment remains radical surgery, although radiotherapy alone can significantly improve overall survival. Clinical trials are urgently needed to evaluate the potential effect of other treatment modalities, such as immunotherapy and targeted therapy, in SFT patients.

Circulating Tumor Cells as an Auxiliary Diagnostic Tool in Surgery.

BACKGROUND: In general, the presence of circulating tumor cells (CTCs) in peripheral blood (PB) is associated with a relative shorter overall survival in cancer patients. The clinical utility of CTC diagnostics is changing: from prognostic test to an assay predicting therapy response, enabling the right choice of therapy and monitoring the effect of administered therapy. We present two case reports of patients with suspicion of lung and pancreatic cancer, without obtainable preoperative biopsy for histological verification. The focus of the presented study was not to deliver a complete tumor tissue classification to the surgeon, but to answer the question if there is malignant disease or not. The results are based on CTC presence and characterization. MATERIALS AND METHODS: A size-based separation method for viable CTC enrichment from anticoagulated PB was used. The separated cells were cytomorphologically examined using vital fluorescent microscopy. Additionally, to confirm the epithelial origin of the cells on the separation membrane, CTC gene expression analysis was performed. RESULTS: CTCs were successfully enriched and cultured in vitro in both tested samples. The epithelial character of the captured cells was confirmed by quantitative-polymerase chain reaction (qPCR) analysis for a set of tumor-associated genes. CONCLUSION: Detection of cancer cells in PB (liquid biopsy) and their molecular characterization could significantly help complete the tumor diagnostic process in a time-efficient manner.

The contribution of gastric emptying scintigraphy to the treatment of obesity with gastric bandage--preliminary results.

INTRODUCTION: Gastric banding for morbid obesity is among the least mutilating of procedures used in bariatric surgery and is classified as a restrictive surgical method. Although it is widespread, so far, however the mechanism responsible has not been fully explained. METHODS AND RESULTS: The authors present the preliminary results from scintigraphic examination of the evacuation ability of the stomach using food labeled with (99m)Tc-colloid in six obese patients with a gastric bandage. This initial study showed that the functionality of the bandage demonstrated as a significant drop in body weight, is connected with slower evacuation of the stomach. However, the use of adjustable bandages would have significantly slowed and restricted the passage of food through the cardia of the stomach. CONCLUSIONS: Since it can be extremely difficult to adequately objectively determine the functionality of gastric bandages, evaluating the gastric emptying scintigraphy may be useful in fulfilling this purpose.

Radio-guided sentinel node detection during the surgical treatment of rectal cancer.

OBJECTIVE: The detection of sentinel nodes is performed in various types of malignant disease. The aim of this study was to evaluate the results of the radiodetection of sentinel nodes, based on the use of Tc-colloid, during the surgical treatment of rectal cancer. METHODS: In 2003-2004, 42 patients (24 males and 18 females; average ages of 62.4 and 67 years, respectively) were examined during rectal carcinoma surgical procedures. Miles abdominoperineal rectal resection was performed in nine cases; 33 patients underwent low anterior rectum resection by total mesorectal excision. On the day of the operation, a transanal submucosal infiltration of colloid labelled with radioactive 99mTc was performed; infiltration was performed strictly peritumorally. After the operation, radiodetection of the surgical specimens (using a hand-held gamma probe) was performed. The areas of higher radioactivity were marked. The specimens were then examined by a histopathologist. The nodes found closest to the marked areas were considered to be 'sentinel nodes'. The results of scintigraphy and postoperative radiodetection were checked by histological examination. All the discovered lymph nodes were examined by haematoxylin and eosin staining; when this was negative, immunohistochemical examination with cytokeratin was used for the sentinel nodes. RESULTS: In 36 of the 42 patients, the data obtained by scintigraphy and radiodetection were in agreement with histopathological proof of a sentinel node. The sensitivity of the method in this group of patients was 86% (95% confidence limits: 70.75-94.05). CONCLUSIONS: The scintigraphic method of detection of sentinel nodes in total mesorectal excision is not therapeutic, but diagnostic, and demonstrates a high level of reliability. It can be used to indicate the nodes that should be examined to detect the presence of possible micrometastases immunohistochemically. However, this method cannot be used for all detected nodes as it is very demanding. In the evaluated group of patients, there were no intraoperative or postoperative complications caused by this diagnostic method.