Functional reserve capacity

Stress susceptibility Loss of functional reserve capacity... 

IUGR) with elevated risk levels of these diseases (Lau Rogers, 2005). The basis of the association is believed to be that alterations in nutrient availability (or other environmental stressors) lead to short-term adaptive measures in the fetus (involving altered homeostatic set-points) that later result in metabolic disorders when the stressor is relieved. The metabolic alterations, in turn, then gradually contribute to increased risk with ageing. It is important to note that functional developmental toxicity may be evident only after long latency periods and may be difficult to ascertain due to the functional reserve capacity of many organ systems. 

Age-associated physiologic changes may cause reductions in functional reserve capacity (i.e., the ability to respond to physiologic challenges or stresses) and the ability to preserve homeostasis, thus making an elder susceptible to decompensation in a stressful... 

Newer and potentially better hepatic function index continues to captivate researchers. A recent report indicates that hippurate ratio is a good measure of functional hepatocyte capacity [13]. The procedure monitors the conjugation of glycine to p-aminobenzoic acid by liver enzymes and may provide unique information on functional hepatic reserve. 

A variety of conditions may predispose certain segments of the population to carbon tetrachloride toxicity. Persons with alcoholic cirrhosis, or other liver diseases which have significantly diminished the functional reserve of the liver, have a reduced capacity to tolerate carbon tetrachloride-induced hepatotoxicity. The same is true for carbon tetrachloride-induced nephrotoxicity in people with significant renal dysfunction from other causes. Diabetics may be particularly susceptible to carbon... 

Yamada et al. suggested that benzoate-metabolizing capacity, especially as indicated by the mean transit time value of the serum benzoate, appears to be a better index than the indocyanine green clearance rate for determining hepatic functional reserve in chronic lever disease [40],... 

The threshold for toxic effects occurs at the point where the body s ability to detoxify a substance or repair toxic injury has been exceeded. For most organs there is a reserve capacity in such a way that the loss of some organ function does not decrease performance. For example, the development of cirrhosis in the liver may not result in a clinical effect until over 50% of the liver has been replaced by fibrous tissue. 

At first sight the cardiac effects might seem likely to be disadvantageous rather than advantageous, and indeed maximum exercise capacity is reduced. But the heart has substantial functional reserves so that use may be made of the desired properties in the diseases listed below, e.g. angina, without... 

This study showed that the filtration reserve capacity of the kidney is lost when elevated microproteinuria is present, but that there was no functional impairment at a renal Cd burden not yet causing microproteinuria. Implicitly, it validated the proposal of a CdU of 10 pg Cd/ g creatinine as biological exposure limit to prevent microproteinuria in male Cd workers. 

FIGURE 25-1. Lung volumes and capacities. ERV = expiratory reserve volume FRC = functional residual capacity IC = inspiratory capacity IRV = inspiratory reserve volume RV = residual volume TLC = total lung capacity VC = vital capacity Vj = tidal volume. 

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