NO and HNO donors,nitrones, and nitroxides: Past,present, and future

The biological effects attributed to nitric oxide (^?NO) and nitroxyl (HNO) have been extensively studied, propelling their array of putative clinical applications beyond cardiovascular disorders toward other age‐related diseases, like cancer and neurodegenerative diseases. In this context, the unique properties and reactivity of the N‐O bond enabled the development of several classes of compounds with potential clinical interest, among which ^?NO and HNO donors, nitrones, and nitroxides are of particular importance. Although primarily studied for their application as cardioprotective agents and/or molecular probes for radical detection, continuous efforts have unveiled a wide range of pharmacological activities and, ultimately, therapeutic applications. These efforts are of particular significance for diseases in which oxidative stress plays a key pathogenic role, as shown by a growing volume of in vitro and in vivo preclinical data. Although in its early stages, these efforts may provide valuable guidelines for the development of new and effective N‐O‐based drugs for age‐related disorders. In this report, we review recent advances in the chemistry of NO and HNO donors, nitrones, and nitroxides and discuss its pharmacological significance and potential therapeutic application.     

Lipid messenger, diacylglycerol, and its regulator, diacylglycerol kinase, in cells, organs, and animals: history and perspective

Diacylglycerol kinase (DGK) metabolizes diacylglycerol (DG), a glycerolipid containing two acyl chains, to convert phosphatidic acid. DG is produced through phosphoinositide turnover within the membrane and is well known to act as a second messenger that modulates the activity of protein kinase C in the cellular signal transduction. Recent studies have revealed that DG also activates several proteins, including Ras guanine-nucleotide releasing protein and ion channels such as transient receptor potential proteins. Therefore, DGK is thought to participate in a number of signaling cascades by modulating levels of DG. Previous studies have disclosed that DGK is composed of a family of the isozymes, which differ in the structure, enzymological property, gene expression and localization, subcellular localization, and binding molecules. The present review focuses on the stories of phosphoinositide turnover and DG, including historical views, structural features, metabolism, and relevant cellular phenomena, together with the characteristics of DGK isozymes and the pathophysiological findings on animal studies using knockout mice and models for human diseases. Now it is being revealed that the structural and functional diversity and heterogeneity of and around DGK support the proper arrangement of the complex signal transduction machinery.     

Heat, cold, noise, and vibration

Exposure to a cold environment induces a number of physiological alterations, the most serious being hypothermia. This state can occur in all individuals, but the very young and the elderly are more susceptible. Environmental and industrially generated high ambient temperature can place further stress on aged individuals and workers, resulting in a complex symptom picture. Morbidity and death may result from such exposures. Causative factors have been identified. Noise exposure induces hearing losses above those secondary to the aging process. Psychophysiological effects during noise exposure are considered to result from the sympathetic activity secondary to a general stress reaction. Vibration from the use of power tools results in Raynaud's phenomenon. However, modification of power tools has reduced the symptoms associated with vibration exposure. Termination of exposure to vibration appears eventually to reduce symptoms related to white-finger spasms. Interaction between these stressors has not been clarified because of the complex effects of each. The need for additional information about the response to these stressors is evident.     

Thoughts,images, worry,and anxiety

Recent models suggest that worry is primarily a verbal-linguistic process that enables images to be avoided and reduces somatic activation. Five-hundred and two subjects completed a questionnaire that assessed variables related to generalized anxiety disorder (GAD) criteria and also asked subjects to indicate the percentage of thoughts and images while worrying. Subjects were divided into excessive worriers (worry excessively about two or more topics more days than not for at least the last 6 months) and ordinary worriers (those who did not meet the previous criteria). As predicted, worry was reported as being composed predominantly of thoughts rather than images, and excessive worriers reported a significantly higher percentage of thoughts compared to ordinary worriers. The number of somatic symptoms was positively correlated with the percentage of images. This relationship was stronger among excessive worriers than ordinary worriers, specifically for autonomic hyperactivity symptoms. Further, in the excessive worry group only there was a significant negative correlation between the number of autonomic hyperactivity symptoms and the percentage of thoughts.This research was partially supported by grants from les Fonds de Recherche en Santé de Québec and the Medical Research Council of Canada. The study was completed while the first author was supported by the Medical Research Council of Canada.The authors gratefully acknowledge the assistance of France Blais for recruiting subjects, administering questionnaires, and entering data.     

Platelets,thrombosis, coagulation,and atherosclerosis

When I first got the invitation to join a medical delegation going to Moldova, I thought for a moment that our destination was the fictional country in the old Marx Brothers movie Duck Soup. On further checking, it turns out that entertaining place was called Freedonia. I now know that Moldova is indeed a real country, bordered on the west by Romania and on the other three sides by the Ukraine. It is a proud country, rich with traditions, and its people are warm, giving, eager to learn ways to improve their healthcare system, and deeply appreciative of our attempts to help them in the task.     

Tetracyclines, chloramphenicol, erythromycin, and clindamycin

The tetracyclines are effective in the treatment of Chlamydia, Mycoplasma pneumoniae, and rickettsial infections and may also be used for gonococcal infections in patients unable to tolerate penicillins. These drugs may cause gastrointestinal irritation, photo-toxic dermatitis, diarrhea, vestibular damage, and hepatotoxicity in pregnant women. Chloramphenicol is used primarily for anaerobic infections, Haemophilus influenzae meningitis, and typhoid fever. The most important toxic effect of chloramphenicol is bone marrow suppression, which can be dose related or idiosyncratic. Erythromycin is the drug of choice for the treatment of infections caused by M. pneumoniae, Legionella species, group A beta-hemolytic streptococci, and Streptococcus pneumoniae. The frequency of serious untoward effects associated with the use of erythromycin is low; epigastric distress may occur. Clindamycin is active against Bacteroides fragilis and other anaerobic microorganisms. Pseudomembranous enterocolitis has developed in as many as 10% of patients taking this drug. The use of clindamycin should be discontinued promptly if diarrhea occurs.