Vital organs

Ra.dia.tlon Shielding. Like lead, bismuth absorbs radiation. Therefore, bismuth ahoys are widely used in the medical industry during radiation therapy. The ahoy is molded to the shape of various organs that are to be shielded. Then the molds are placed between the radiation source and the patient to protect the patient s vital organs from radiation exposure. 

The toxic symptoms from inhalation of nickel carbonyl are beUeved to be caused by both nickel metal and carbon monoxide. In many acute cases the symptoms ate headache, di22iQess, nausea, vomiting, fever, and difficulty in breathing. If exposure is continued, unconsciousness follows with subsequent damage to vital organs and death. Iron pentacarbonyl produces symptoms similar to nickel carbonyl but is considered less toxic than nickel carbonyl. 

An electric current, rather than voltage, through a human body may cause shock and can damage vital organs of the body as follows ... 

Late Toxicity - Where there is evidence that a chemical can cause cancer, mutagenic effects, teratogenic effects, or delayed injury to vital organs such as the liver or kidney, a qualitative description of the chemical is given. The term implies long-term or chronic effects due to exposure to the chemical. 

Mean arterial pressure and cardiac output, an expression of the amount of blood that the heart pumps each minute, are the key Indicators of the normal functioning of the cardiovascular system. Mean arterial pressure is strictly controlled, but by changing the cardiac output, a person can adapt, e.g., to increased oxygen requirement due to increased workload. Blood flow in vital organs may vary for many reasons, but is usually due to decreased cardiac output. However, there can be very dramatic changes in blood pressure, e.g., blood pressure plummets during an anaphylactic allergic reaction. Also cytotoxic chemicals, such as heavy metals, may decrease the blood pressure. 

Polonium is extremely toxic at all concentrations and is never beneficial. Severe radiation damage of vital organs follows ingestion of even the minutest concentrations and, for the most commonly used isotope, °Po, the maximum permissible body burden is 0.03/zCi, i.e. 1100 Bq (=1100s ), equivalent to 7 x 10 g of the element. Concentrations of airborne Po compounds must be kept below 4 x 10" " mgm . ... 

Occurs when the volume of extracellular fluid is significantly diminished. Examples include hemorrhage, fluid loss caused by burns, diarrhea, vomiting, or excess diuresis Occurs when the heart is unable to deliver an adequate cardiac output to maintain perfusion to the vital organs. Examples include as the result of an acute myocardial infarction, ventricular arrhythmias, congestive heart failure (CHF), or severe cardiomyopathy. 

When a cardiotonic drug is administered, die positive inotropic action increases the force of die contraction, resulting in an increased cardiac output. When cardiac output is increased, the blood supply to die kidneys and otiier vital organs is increased. Water, electrolytes, and waste products are removed in adequate amounts, and tiie symptoms of inadequate heart action or HF are relieved, hi most instances, the heart rate also decreases. This occurs because vital organs are now receiving an adequate blood supply because of the increased force of myocardial contraction. 

Monitor for adequate perfusion of vital organs through assessment of mental status, creatinine clearance, liver function tests, and a stable HR between 50 and 100 beats per minute. Additionally, adequate skin and muscle blood perfusion and normal pH is desirable. 

Such clots—also known as emboli—present a serious hazard by their potential for blocking circulation of blood to vital organs. The considerable research devoted to agents that will lyse the fibrin in clots has led to the development of the clinically useful agent, uj-okinase. This drug is a fibrinolytic proteinaceous enzyme isolated from human urine. The difficulty involved in isolation of significant amounts and the antigenicity of urokinase and a related... 

In terms of pharmacokinetics, many host factors, such as the route of administration, the metabolism, the catabolism and clearance will considerably determine the anti neoplastic success of a drug. One major difficulty with the clinical effectiveness of chemotherapy of neoplastic diseases is the requirement that it kill malignant tumor cells at doses that allow cells in the patient s vital organs to survive so that the recovery can occur. In other words, it is to obtain a reasonably safe therapeutic index favoring introduction into clinical practice. 

Loss of plasma volume leads to a decrease in MAP. Baroreceptors located in the aortic and carotid sinuses detect this fall in MAP and elicit reflex responses that include an increase in the overall activity of the sympathetic nervous system. Sympathetic stimulation of the heart and blood vessels leads to an increase in cardiac output (CO) and increased total peripheral resistance (TPR). These adjustments, which increase MAP, are responsible for the short-term regulation of blood pressure. Although increases in CO and TPR are effective in temporary maintenance of MAP and blood flow to the vital organs, these activities cannot persist indefinitely. Ultimately, plasma volume must be returned to normal (see Table 19.1). 

Acid-base balance involves chemical and physiological processes responsible for the maintenance of the pH of body fluids at levels that allow optimal function of the whole individual. The ability for the body to regulate pH is critically important in maintaining the operation of many cellular enzymes and the function of vital organs, such as the brain and the heart [143],... 

Chandra, J. and G. Durairaj. 1992. Toxicity of toxaphene on histopathology of vital organs in guinea pig, Cavia porcellus. Jour. Environ. Biol. 13 315-322. 

The goal of CPR is the return of spontaneous circulation (ROSC) with effective ventilation and perfusion as quickly as possible to minimize hypoxic damage to vital organs. 

Regardless of the etiology, fall in blood pressure (BP) is compensated by an increase in sympathetic outflow, activation of the renin-angiotensin system, and other humoral factors that stimulate peripheral vasoconstriction. Compensatory vasoconstriction redistributes blood away from the skin, skeletal muscles, kidneys, and GI tract toward vital organs (e.g., heart, brain) in an attempt to maintain oxygenation, nutrition, and organ function. 

Locally applied agents (e.g., dermal or ocular) where systemic exposure or distribution to the vital organs is low ... 

Photosynthesis - process of converting electromagnetic energy of the sun rays into the energy of chemical bonds of vital organic substances. .. [1]. 

To a large extent we will have to rely for our information about these vital organs on data pertaining to blood, secretions, and tissues which can be obtained from well individuals without too great inconvenience. Data with respect to animals, if available, would be pertinent but, because of lack of interest in the potential importance of the study of individual differences, there is little material which is directly applicable to our questions. Incidentally, the use of highly inbred strains of animals in laboratory research has resulted in partially wiping out some of the differences which would be most interesting from the standpoint of our study. 

Safety pharmacology studies have been subdivided into "core battery," "follow-up," and "supplemental" studies.25 The "core battery" studies are aimed to investigate the effects of NCEs on the cardiovascular, respiratory, and central nervous systems that are considered as vital organ systems based on the fact that acute failure of these systems would pose an immediate hazard to human life. In some instances, based on scientific rational, the "core battery" may or may not be supplemented.25 Additionally, ADRs may be either (1) suspected based on the pharmacological class, or the chemical class, or (2) identified... 

Table 13.10 illustrates examples of functional endpoints that have been successfully incorporated into toxicology studies. The examples cover primarily, but are not limited to, the vital organ systems (i.e., cardiovascular, respiratory, and central nervous systems). The repeat-dose toxicology studies offer an ideal opportunity to compare the pharmacological... 

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