The American journal of medicine
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Angiotensin-converting enzyme (ACE) inhibitors have been designed to reduce the generation of angiotensin II, i.e., to block the renin-angiotensin system. Interestingly, there exists a considerable dissociation between the time course of ACE inhibition and that of blockade of the renin-angiotensin system. Due to the greatly improved methodology used to estimate the degree of ACE inhibition in vitro and in vivo, it has become evident that the compensatory increase in renin levels in response to ACE inhibition is the key factor determining the degree and duration of blockade of the renin-angiotensin system resulting from ACE inhibition. A better understanding of these relationships would seem to be useful in determining duration of action and particularly the optimal dose of any ACE inhibitor.
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A variety of pulmonary complications related to the use of freebase cocaine have been reported in the medical literature. Pulmonary barotrauma, hypersensitivity pneumonitis, pulmonary hemorrhage, obliterative bronchiolitis, asthma, and pulmonary edema have all recently been described. The number of reports are few, reflecting either the low incidence of these complications or the lack of recognition of these phenomena as cocaine-related illnesses. ⋯ Whether cardiogenic or non-cardiogenic factors play a role in the development of pulmonary edema in freebase smokers has not yet been determined. Likewise, the roles of either cocaine, tobacco, or adulterants in producing the observed abnormalities of lung function remain controversial. Further reporting of freebase-related pulmonary complications, as well as the development of appropriate animal models, is needed.
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Case Reports
The anemia of chronic disease: spectrum of associated diseases in a series of unselected hospitalized patients.
Previous studies of the anemia of chronic disease (ACD) have generally begun with patients afflicted with one of the classical underlying diseases such as rheumatoid arthritis. The clinical spectrum of ACD has not been thoroughly examined. We hypothesized that many patients have an anemia with the characteristics of ACD but do not have one of the infectious, inflammatory, or neoplastic disorders usually associated with ACD. We therefore evaluated a series of consecutive, unselected, anemic patients admitted to a county hospital. ⋯ When ACD was defined by the abnormalities of iron distribution, which are its most consistent and widely accepted characteristics, the spectrum of associated diseases was much broader than the traditional categories of infectious, inflammatory, and neoplastic disorders, and the overlap with non-ACD was large. Until the etiologic and pathogenetic mechanisms of ACD are better understood, a flexible and inclusive view of this disorder seems appropriate.
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Oxygen consumption (VO2) is independent of oxygen delivery (DO2) above a critical level of DO2. VO2 may become dependent on DO2 when oxygen demand exceeds oxygen supply. We studied DO2 VO2, and exercise capacity in 12 stable, ambulatory patients with chronic obstructive pulmonary disease (COPD) receiving ambient air and 26% oxygen to ascertain whether VO2 is dependent on DO2 in this patient sample. ⋯ These data demonstrate that DO2 may fail to increase in some patients with COPD and resting or exertional hypoxemia when supplemental oxygen is administered because of a reduction in cardiac output; that patients who fail to increase their DO2 are less likely to increase exercise capacity; and that some stable, ambulatory patients with COPD who do not qualify for supplemental oxygen at rest by current standards may have inadequate DO2 to meet physiologic needs.