The Reaction of Fenchone and Camphor Hydrazones with 5-Acyl-4-Pyrones as a Method for the Synthesis of New Polycarbonyl Conjugates: Tautomeric Equilibrium and Antiviral Activity.

Selective synthesis of polycarbonyl conjugates of (+)-fenchone and (+)-camphor was carried out (44-91 % yields) via the ring-opening transformation of 5-acyl-4-pyrones with hydrazones of the corresponding monoterpenoids. A strong influence of the hydrazone fragment on the observed tautomeric equilibrium of the tricarbonyl system was shown. Although the major tautomer of the conjugates is the acyclic polycarbonyl form, the camphor-based conjugates undergo new type of ring-chain tautomerism, diketoenaminone-dihydropyridone equilibrium, and predominantly exist in the cyclic dihydropyridone form in DMSO-d.

Saturation Mutagenesis and Molecular Modeling: The Impact of Methionine 182 Substitutions on the Stability of β-Lactamase TEM-1.

Serine β-lactamase TEM-1 is the first β-lactamase discovered and is still common in Gram-negative pathogens resistant to β-lactam antibiotics. It hydrolyzes penicillins and cephalosporins of early generations. Some of the emerging TEM-1 variants with one or several amino acid substitutions have even broader substrate specificity and resistance to known covalent inhibitors.

Ultrasound Diagnosis and Near-Infrared Spectroscopy in the Study of Encephalopathy in Neonates Born under Asphyxia: Narrative Review.

Brain injury resulting from adverse events during pregnancy and delivery is the leading cause of neonatal morbidity and disability. Surviving neonates often suffer long-term motor, sensory, and cognitive impairments. Birth asphyxia is among the most common causes of neonatal encephalopathy.

Mechanisms and physiological relevance of acid-base exchange in functional units of the kidney.

This review discusses the importance of homeostasis with a particular emphasis on the acid-base (AB) balance, a crucial aspect of pH regulation in living systems. Two primary organ systems correct deviations from the standard pH balance: the respiratory system gas exchange and the kidneys proton/bicarbonate secretion and reabsorption. Focusing on kidney functions, we describe the complexity of renal architecture and its challenges for experimental research.