I. Arginine.

L-Arginine (Arg) is classified as an essential amino acid for birds, carnivores and young mammals and a conditionally essential amino acid for adults. It is converted by arginase to L-ornithine, a precursor of polyamines and urea, which is important in the urea cycle. Arg serves as a precursor for creatine, which plays an essential role in the energy metabolism of muscle, nerve and testis and accounts for Arg catabolism and for the synthesis of agmatine and proteins. Via its ability to increase growth hormone secretion it influences immune function. Depending on nutritional status and developmental stage, normal plasma Arg concentrations in humans and animals range from 95 to 250 micromol/l. Systemic or oral Arg administration has been shown to improve cardiovascular function and reduce myocardial ischemia in coronary artery disease patients. It reduces blood pressure and renal vascular resistance in essential hypertensive patients with normal or insufficient renal function. Although Arg plasma concentrations are not altered in hypercholesterolemic individuals, oral or intravenous Arg administration can reverse endothelial dysfunction in hypercholesterolemic patients and in cigarette smokers. The main importance of Arg is attributed to its role as a precursor for the synthesis of nitric oxide (NO), a free radical molecule that is synthesized in all mammalian cells from L-Arg by NO synthase (NOS). NO appears to be a major form of the endothelium-derived relaxing factor (EDRF). NO and EDRF share similar chemical and pharmacological properties and are derived from the oxidation of a terminal guanidine group of L-Arg. Various mechanisms have been implicated in the defect in vascular relaxation. These include, increased diffusional barrier for NO, L-Arg depletion, altered levels of reactive oxygen, inactivation of NO by superoxide anions (O2-). The independent reactions of O2-, NO and their reaction yielding peroxynitrite are critical in the initiation and maintenance of the atherosclerotic state and contribute to the defect in vasorelaxation. NO also plays a role as a neurotransmitter, mediator of immune response and as signaling molecule. The NO synthesized by iNOS in macrophages contributes to their cytotoxic activity against tumor cells, bacteria and protozoa. Our aim here is to review on some amino acids with high functional priority such as Arg and to define their effective activity in human health and pathologies.     

How I learned what I thought I already knew.

Recently, I experienced cancer from the other side: I have had the privilege of sharing the cancer experience with an intimate other. It was while I lived through this experience, this hand-in-hand, heart-to-heart and soul-by-soul walk with my husband that I really learned what I thought I already knew about how oncology nurses alleviate suffering, help heal and lessen the burden of the cancer illness. The purpose of this paper is to provide the oncology nurse with a portal into a lived experience of a person dying of cancer and to confirm what we do know, describe what we do not know and to lovingly challenge some of our assumptions so that we may become better students of our real teachers: our patients.     

I.V. fluid therapy. Part 2. I.V. fluid selection

I.v. fluid selection depends on the estimated fluid loss, the primary fluid compartment involved, the patient's underlying problem and the physiological and haemodynamic impact of the i.v. solution. Clinically, the most important problem is intravascular fluid volume deficit, which is associated with hypotension, inadequate tissue oxygenation and hypoperfusion of essential organs. Intravascular volume resuscitation is therefore of primary importance. Crystalloid solutions have the disadvantage of only small amounts remaining in the IVS whereas colloids are known as plasma volume expanders due to predominantly remaining in the IVS in the presence of an intact capillary endothelium. Managing i.v. fluid administration requires close observation of the patient's subtle responses that may indicate states of fluid depletion or overload. Understanding the physiological principles of the body's fluid distribution in relation to the clinical assessment of the patient's hydration status, together with knowledge of the selected i.v. solution's properties, will enable the nurse to provide quality nursing care and improve patient outcomes.