N-Functionalization of ß-aminophosphonates: cytotoxic effects of the new derivatives.

ß-Aminophosphonates obtained by the Michael addition of primary amines to the double bond of diethyl vinylphosphonate proved to be suitable starting materials (amine components) in the Kabachnik-Fields reaction with formaldehyde and dialkyl phosphites or secondary phosphine oxides to afford N-phosphonylmethyl- and N-phosphinoylmethyl-ß-aminophosphonates. On the other hand, the starting aminophosphonates were modified by N-acylation using acid chlorides. The N-acyl products were found to exist in a dynamic equilibrium of two conformers as suggested by the broad NMR signals. At 26 °C, there may be rotation around the N-C axis of the acylamide function. At the same time, low-temperature NMR measurements at -5 °C revealed the presence of two distinct rotamers that could be characterized by 31P, 13C and 1H NMR data. The modified ß-aminophosphonic derivatives were subjected to a comparative structure-activity analysis on MDA-MB-231, PC-3, A431 and Ebc-1 tumor cell lines, and in a few cases, significant activity was detected.

The Last Decade of Optically Active α-Aminophosphonates.

α-Aminophosphonates and related compounds are important due to their real and potential biological activity. α-Aminophosphonates may be prepared by the Kabachnik-Fields condensation of oxo compounds, amines and dialkyl phosphites, or by the aza-Pudovik addition of the same P-reagents to imines. In this review, the methods that allow for the synthesis of α-aminophosphonates with optical activity are surveyed. On the one hand, optically active catalysts or ligands may induce enantioselectivity during the Kabachnik-Fields reaction. On the other hand, asymmetric catalysis during the aza-Pudovik reaction, or hydrogenations of iminophosphonates, may prove to be a useful tool. Lastly yet importantly, it is possible to start from optically active reagents that may be associated with diastereoselectivity. The "green" aspects of the different syntheses are also considered.

Transdermal Delivery of α-Aminophosphonates as Semisolid Formulations-An In Vitro-Ex Vivo Study.

α-Aminophosphonates are organophosphorus compounds with an obvious similarity with α-amino acids. Owing to their biological and pharmacological characteristics, they have attracted the attention of many medicinal chemists. α-Aminophosphonates are known to exhibit antiviral, antitumor, antimicrobial, antioxidant and antibacterial activities, which can all be important in pathological dermatological conditions. However, their ADMET properties are not well studied. The aim of the current study was to provide preliminary information about the skin penetration of three preselected α-aminophosphonates when applying them as topical cream formulations in static and dynamic diffusion chambers. The results indicate that aminophosphonate 1a, without any substituent in the para position, shows the best release from the formulation and the highest absorption through the excised skin. However, based on our previous study, the in vitro pharmacological potency was higher in the case of para-substituted molecules 1b and 1c. The particle size and rheological studies revealed that the 2% cream of aminophosphonate 1a was the most homogenous formulation. In conclusion, the most promising molecule was 1a, but further experiments are proposed to uncover the possible transporter interactions in the skin, optimize the topical formulations and improve PK/PD profiles in case of transdermal delivery.

Cytotoxic Activity of α-Aminophosphonic Derivatives Coming from the Tandem Kabachnik-Fields Reaction and Acylation.

Encouraged by the significant cytotoxic activity of simple α-aminophosphonates, a molecular library comprising phosphonoylmethyl- and phosphinoylmethyl-α-aminophosphonates, a tris derivative, and N-acylated species was established. The promising aminophosphonate derivatives were subjected to a comparative structure-activity analysis. We evaluated 12 new aminophosphonate derivatives on tumor cell cultures of different tissue origins (skin, lung, breast, and prostate). Several derivatives showed pronounced, even selective cytostatic effects. According to IC50 values, phosphinoylmethyl-aminophosphonate derivative 2e elicited a significant cytostatic effect on breast adenocarcinoma cells, but it was even more effective against prostatic carcinoma cells. Based on our data, these new compounds exhibited promising antitumor activity on different tumor types, and they might represent a new group of alternative chemotherapeutic agents.

Multicolored MIS-C, a single-centre cohort study.

BACKGROUND: The aim of this study was to investigate the clinical and laboratory parameters that can predict the severity of Multisystem Inflammatory Syndrome in Children (MIS-C) at admission. METHODS: We conducted a single-center, partly retrospective, partly prospective, observational cohort study between November 1, 2020 and December 31, 2021, which included patients aged from 1 month to 19 years, meeting the diagnostic criteria of MIS-C. We categorized the patients into three subgroups based on clinical and laboratory markers and assessed the predictive value of these factors in terms of ICU administration and cardiac abnormalities. RESULTS: 53 patients were classified in the following subgroups: Kawasaki-like disease (group 1) (47.2%, n = 25), shock with or without acute cardiac dysfunction (group 2) (32%, n = 17), fever and inflammation (group 3) (20.8%, n = 11). Subgroup analysis revealed that patients with shock and KD at initial presentation had significantly more severe manifestation of MIS-C requiring intensive care unit (ICU) treatment. Of the initial laboratory values, only CRP showed a significant difference between the 3 clinical groups, being lower in group 3. 52.6% of patients were admitted to the ICU. The median length of ICU stay was 3 days (range 3-20). ICU admission was more likely in patients with shortness of breath, renal failure (AKI) and patients with significantly increased concentrations of ferritin, D-dimer, INR and significantly milder increase concentration of fibrinogen. We found that fibrinogen and ferritin levels are independent risk factors for ICU admission. Cardiac abnormalities were found in 56.6% of total (30/53), with the following findings: decreased left ventricular function (32%), coronary abnormality (11.3%), pericardial effusion (17%), arrhythmia (32.1%) and mitral regurgitation (26.6%). Diarrhea and conjunctivitis at the initial presentation with significantly elevated CRP, Pro-BNP and blood pH concentrations were found to be a potential predisposing factor for decreased cardiac function while Pro-BNP and pH were independent risk factors for MIS-C. Regardless of the initial symptoms of MIS-C, the outcome was generally favorable. CONCLUSIONS: Clinical characteristics and baseline laboratory values ​​may help identify patients at increased risk for severe disease outcome, such as need for intensive care, presence of shock and decreased cardiac function. TRIAL REGISTRATION: Participation consent was not reqired and ethical considerations were unnecessary, since we did not perform any extra interventions, only the necessary and usual therapeutic and diagnostic methods were used.

Daily serum phosphate increase as early and reliable indicator of kidney injury in children with leukemia and lymphoma developing tumor lysis syndrome.

BACKGROUND: Tumor lysis syndrome (TLS) and its most serious complication, acute kidney injury (AKI) are one of the emergency conditions in onco-hematology. It is difficult to predict the degree of kidney involvement. Therefore, we studied children with leukemia and lymphoma treated in four Hungarian tertiary centers (inpatient university clinics) retrospectively (2006-2016) from a nephrological aspect. METHOD: Data of 31 pediatric patients were obtained from electronic- and paper-based medical records. Physical status, laboratory test results, treatments, and outcomes were assessed. Patients were analyzed according to both "traditional" TLS groupings, as laboratory TLS or clinical TLS, and nephrological aspect based on pRIFLE classification, as mild or severe AKI. RESULTS: Significant differences were found between the changes in parameters of phosphate homeostasis and urea levels in both classifications. Compared to age-specific normal phosphate ranges, before the development of TLS, hypophosphatemia was common (19/31 cases), while in the post-TLS period, hyperphosphatemia was observed (26/31 cases) most frequently. The rate of daily change in serum phosphate level was significant in the nephrological subgroups, but peaks of serum phosphate level show only a moderate increase. The calculated cut-off value of daily serum phosphate level increased before AKI was 0.32 mmol/L per ROC analysis for severe TLS-AKI. The 24-h urinalysis data of eight patients revealed transiently increased phosphate excretion only in those patients with TLS in whom serum phosphate was elevated in parallel. CONCLUSION: Daily serum phosphate level increase can serve as a prognostic factor for the severity of pediatric TLS, as well as predict the severity of kidney involvement. A higher resolution version of the Graphical abstract is available as Supplementary information.

New N-acyl- as well as N-phosphonoylmethyl- and N-phosphinoylmethyl-α-amino-benzylphosphonates by acylation and a tandem Kabachnik-Fields protocol.

Diethyl α-benzylamino- and α-amino-benzylphosphonates obtained by the Kabachnik-Fields reaction were useful intermediates in the synthesis of other derivatives. Acylation of α-aminophosphonates with acyl chlorides led to the corresponding N-acyl species existing under a dynamic equilibrium of two conformers. Judging from the broad NMR signals, the sterically most crowded N-benzoyl-N-benzyl derivative suffered a hindered rotation around the N-C axis to the acyl carbon atom at 26 °C. Low temperature NMR measurements at -10 °C showed the presence of two distinct rotamers that were characterized. The other acylated α-amino-benzylphosphonates prepared revealed a less hindered rotation. Single crystal X-ray diffraction of the NH-propionyl species showed a dimer, in which the two molecules were held together by rare intermolecular PO⋯HN bonds. On the other hand, substituted α-benzylamino-benzylphosphonates prepared by phospha-Mannich reactions were employed, as a new approach, in a second Kabachnik-Fields condensation by reaction with formaldehyde and dialkyl phosphites or secondary phosphine oxides to afford novel N-phosphonoylmethyl- and N-phosphinoylmethyl-α-amino-benzylphosphonates. The structure of the new products was confirmed by two-dimensional NMR spectroscopy. A symmetrical bis derivative was prepared in a diastereoselective manner. A related tris(phosphonoylmethyl)amine species was also synthesized.

Efficient Synthesis of Acylated, Dialkyl α-Hydroxy-Benzylphosphonates and Their Anticancer Activity.

An efficient method applying acyl chlorides as reagents was developed for the acylation of the hindered hydroxy group of dialkyl α-hydroxy-benzylphosphonates. The procedure did not require any catalyst. A few acylations were also performed with the SC-enantiomer of dimethyl α-hydroxy-benzylphosphonate, and the optical purity was retained. A part of the acyloxyphosphonates was tested against eight tumor cell lines of different tissue origin at c = 50 µM concentration. The compounds elicited moderate cytostatic effect against breast, skin, prostate, colon, and lung carcinomas; a melanoma cell line; and against Kaposi's sarcoma cell lines. Then, dose-dependent cytotoxicity was assayed, and benzoylation of the α-hydroxy group was identified as a moiety that increases anticancer cytotoxicity across all cell lines. Surprisingly, a few analogues were more toxic to multidrug resistant cancer cell lines, thus evading P-glycoprotein mediated drug extrusion.

Reduction in hypoxia-reoxygenation-induced myocardial mitochondrial damage with exogenous methane.

Albeit previous experiments suggest potential anti-inflammatory effect of exogenous methane (CH4 ) in various organs, the mechanism of its bioactivity is not entirely understood. We aimed to investigate the potential mitochondrial effects and the underlying mechanisms of CH4 in rat cardiomyocytes and mitochondria under simulated ischaemia/reperfusion (sI/R) conditions. Three-day-old cultured cardiomyocytes were treated with 2.2% CH4 -artificial air mixture during 2-hour-long reoxygenation following 4-hour-long anoxia (sI/R and sI/R + CH4 , n = 6-6), with normoxic groups serving as controls (SH and SH + CH4 ; n = 6-6). Mitochondrial functions were investigated with high-resolution respirometry, and mitochondrial membrane injury was detected by cytochrome c release and apoptotic characteristics by using TUNEL staining. CH4 admixture had no effect on complex II (CII)-linked respiration under normoxia but significantly decreased the complex I (CI)-linked oxygen consumption. Nevertheless, addition of CH4 in the sI/R + CH4 group significantly reduced the respiratory activity of CII in contrast to CI and the CH4 treatment diminished mitochondrial H2 O2 production. Substrate-induced changes to membrane potential were partially preserved by CH4 , and additionally, cytochrome c release and apoptosis of cardiomyocytes were reduced in the CH4 -treated group. In conclusion, the addition of CH4 decreases mitochondrial ROS generation via blockade of electron transport at CI and reduces anoxia-reoxygenation-induced mitochondrial dysfunction and cardiomyocyte injury in vitro.

Synthesis of α-Aminophosphonates and Related Derivatives; the Last Decade of the Kabachnik-Fields Reaction.

The Kabachnik-Fields reaction, comprising the condensation of an amine, oxo compound and a P-reagent (generally a >P(O)H species or trialkyl phosphite), still attracts interest due to the challenging synthetic procedures and the potential biological activity of the resulting α-aminophosphonic derivatives. Following the success of the first part (Molecules 2012, 17, 12821), here we summarize the synthetic developments in this field accumulated in the last decade. The procedures compiled include catalytic accomplishments as well as catalyst-free and/or solvent-free "greener" protocols. The products embrace α-aminophosphonates, α-aminophosphinates, and α-aminophosphine oxides along with different bis derivatives from the double phospha-Mannich approach. The newer developments of the aza-Pudovik reactions are also included.

Methane supplementation improves graft function in experimental heart transplantation.

BACKGROUND: Maintenance of cell viability during cold storage is a key issue in organ transplantation. Methane (CH4) bioactivity has recently been recognized in ischemia/reperfusion conditions; we therefore hypothesized that cold storage in CH4-enriched preservation solution can provide an increased defense against organ dysfunction during experimental heart transplantation (HTX). METHODS: The hearts of donor Lewis rats were stored for 60 minutes in cold histidine-tryptophan-ketoglutarate (Custodiol [CS]) or CH4-saturated CS solution (CS-CH4) (n = 12 each). Standard heterotopic HTX was performed, and 60 minutes later, the left ventricular (LV) pressure-volume relationships LV systolic pressure (LVSP), systolic pressure increment (dP/dtmax), diastolic pressure decrement, and coronary blood flow (CBF) were measured. Tissue samples were taken to detect proinflammatory parameters, structural damage (by light microscopy), endoplasmic reticulum (ER) stress, and apoptosis markers (CCAAT/enhancer binding protein [C/EBP] homologous protein, GRP78, glycogen synthase kinase-3ß, very low-density lipoprotein receptor, caspase 3 and 9, B-cell lymphoma 2, and bcl-2-like protein 4), whereas mitochondrial functional changes were analyzed by high-resolution respirometry. RESULTS: LVSP and dP/dtmax increased significantly at the largest pre-load volumes in CS-CH4 grafts as compared with the CS group (114.5 ± 16.6 mm Hg vs 82.8 ± 4.6 mm Hg and 3,133 ± 430 mm Hg/s vs 1,739 ± 169 mm Hg/s, respectively); the diastolic function and CBF (2.4 ± 0.4 ml/min/g vs 1.3 ± 0.3 ml/min/g) also improved. Mitochondrial oxidative phosphorylation capacity was more preserved (58.5 ± 9.4 pmol/s/ml vs 27.7 ± 6.6 pmol/s/ml), and cytochrome c release was reduced in CS-CH4 storage. Signs of HTX-caused myocardial damage, level of ER stress, and the transcription of proapoptotic proteins were significantly lower in CS-CH4 grafts. CONCLUSION: The addition of CH4 during 1 hour of cold storage improved early in vitro graft function and reduced mitochondrial dysfunction and activation of inflammation. Evidence shows that CH4 reduced ER stress-linked proapoptotic signaling.

Comparative reactivity analysis of small-molecule thiol surrogates.

Targeted covalent inhibitors represent an increasingly popular approach to modulate challenging drug targets. Since covalent and non-covalent interactions are both contributing to the affinity of these compounds, evaluation of their reactivity is a key-step to find feasible warheads. There are well-established HPLC- and NMR-based kinetic assays to tackle this task, however, they use a variety of cysteine-surrogates including cysteamine, cysteine or acetyl-cysteine and GSH. The diverse nature of the thiol sources often makes the results incomparable that prevents compiling a comprehensive knowledge base for the design of covalent inhibitors. To evaluate kinetic measurements from different sources we performed a comparative analysis of the different thiol surrogates against a designed set of electrophilic fragments equipped with a range of warheads. Our study included seven different thiol models and 13 warheads resulting in a reactivity matrix analysed thoroughly. We found that the reactivity profile might be significantly different for various thiol models. Comparing the different warheads, we concluded that - in addition to its human relevance - glutathione (GSH) provided the best estimate of reactivity with highest number of true positives identified.

Recycling of bowel content: the importance of the right timing.

INTRODUCTION: Extracorporeal stool transport (recycling of chyme discharged from the proximal stoma end to the distal end of a high jejunostomy or ileostomy) is thought to be beneficial in preventing malabsoprtion, sodium loss, cholestasis and atrophy of the distal intestine until restoration of the intestinal continuity becomes possible. However little is known about its adverse effects. Our aim was to investigate the microbiological safety of recycling. MATERIAL AND METHOD: Native samples were taken from the proximal stoma in 5 premature neonates who underwent an ileostomy or a jejunostomy due to necrotising enterocolitis, for qualitative culture. The first sample was drawn immediately after the change of the stoma bag, further samples were sent from the stoma bag at 30, 60, 90, 120, 150, and 180min later. The samples were inoculated by calibrated (10 µl) loops onto blood agar (5% sheep blood), eosin-methylene blue agar and anaerobic blood agar, respectively (Oxoid). The aerobic plates were incubated for 18-20 h at 5% CO2, whereas the anaerobic plates were incubated for 24-48 h in an anaerobic chamber (Concept 400). The bacterial strains were identified to species level by specific biochemical reactions, RapID-ANA II system (Oxoid) and ID32E, Rapid ID 32 Strep ATB automatic system cards (bioMérieux). RESULTS: The number of colony forming unit (CFU) of Gram-negative bacteria (mainly E. coli) exponentially increased after 30 min and reached 10(5)/ml after 120 min. Gram-positive strains (primarily E. faecalis) were detected after 60 min and CFU increased to 10(5)/ml after 120 min. The number of anaerobic (principally Bacteroides fragilis) CFU started to increase after 120 min. In two cases coagulase negative Staphylococcus strains were isolated the earliest in the chyme. The average of total CFU approached 10(5)/ml after 90 min and exceeded 10(5)/ml after 120 min. CONCLUSION: The chyme in the stoma bag is colonized by commensal facultative pathogenic enteral/colonic as well as skin flora species after 120 min. Recycling of stoma bag content may be dangerous after 90 min.

[Biochemical alterations in patients with Down syndrome]. / Biokémiai eltérések Down-szindromás betegekben.

UNLABELLED: Down syndrome is a chromosome abnormality with specific clinical symptoms and mental retardation caused by trisomy of chromosome 21. The basic genetic change cannot be cured, the control of the associated symptoms, however, may improve the patients' quality of life. AIMS: Authors studied the possible correlations between the Down-specific genes and the related biochemical changes. Expression of superoxide dismutase, cystathionine-beta-synthase and S100 protein was investigated. Further aim of the study was to determine the total serum antioxidant capacity (transferrin, ferritin, total protein, albumin and bilirubin) along with the extracellular antioxidants as well as concentrations of homocysteine, folic acid, and vitamin B 12 . To assess the vascular damage, the activity of NAG and S100B level was measured. METHODS: Standard laboratory methods were used to determine the antioxidant capacity (Stocks, 1974), homocysteine (HPLC), folic acid (capture, IMX-Abbott), vitamin B 12 (MEIA, IMX-Abbott), S100 B protein (chemiluminescence sandwich immunoassay) levels, and N-acetyl-beta-D-glucosaminidase (spectrophotometry). RESULTS: Plasma homocysteine value proved to be lower in 7 of the 30 and higher in 6 of the 30 patients studied than the reference range. Plasma homocysteine was found 95 +/- 21% of the reference value. Relative value of plasma folic acid - expressed in percent of the normal value - was 85 +/- 51%, and that of B 12 was 78 +/- 30%. Deficiency of folic acid was detected in 2 of the 30, decreased level of B 12 in 2 of the 30 patients enrolled. No difference was found in antioxidant activity values between Down syndrome patients and healthy controls, however, neither of them reached the adult reference range. S100 protein concentration of 4-8 times higher values (average value: 0.68 +/- 0.27 microg/l) than upper limit of the reference range was observed (> 1 year: > 0.15 microg/l). Mean value of serum N-acetyl-beta-D-glucosaminidase remained within the reference range (10-30 U/l). No statistically significant correlation between the antioxidant activity and N-acetyl-beta-D-glucosaminidase values could be observed. CONCLUSION: The lower homocysteine, folic acid and B 12 values may be considered as the consequence of an increased cystathionine-beta-synthase activity ("atheroma free model"). There was no significant alteration in antioxidant activity level. It can be supposed that the hydrogene peroxide produced due to increased expression of superoxide dismutase is metabolized by the induced glutathione-peroxidase and catalase keeping by this the balance of the antioxidant system. This hypothesis is supported by the normal N-acetyl-beta-D-glucosaminidase values not indicating any vascular damage. The high S100 values, however, reflect certain brain damage which shows a progress with the age. Based on these experiences, regular control of these parameters is recommended. Furthermore authors think that folic acid supplementation is indicated in order to improve the patients' learning capacity, inhibit the development of Alzheimer symptoms and improve the quality of life.