摘要:

AbstractAngiotensin I-converting enzyme (ACE) is a peptidyldipeptide hydrolase that is located mainly on the luminal surface of vascular endothelial cells but also in cells derived from the monocyte-macrophage system. Physiologically, ACE is a key enzyme in the renin-angiotensin system, converting angiotensin I into the potent vasopressor angiotensin II and also inactivating the vasodilator bradykinin.Increased serum ACE activity (SACE) has been reported in pathologies involving a stimulation of the monocytic cell line, primarily granulomatous diseases. Sarcoidosis is the most frequent and the better studied of these diseases; high SACE is not only a well-established marker for the diagnosis but is also a useful tool for following its course and evaluating the effect of therapy. SACE can also be increased in nonsarcoidotic pulmonary granulomatous diseases such as silicosis and asbestosis, in extrathoracic granulomatous pathologies such as Gauchers disease and leprosis, and, to a lesser extent, in nongranulomatous disorders such as hyperthyroidism or cholestasis. On the other hand, monitoring sarcoidosis obviates the measurement of ACE activity in other biological fluids, e.g., broncho-alveolar and cerebrospinal fluids, in the search of a locoregional dissemination or dissimulation of the disease.Decreased SACE has been reported in vascular pathologies involving an endothelial abnormality, e.g., deep vein thrombosis, and in endothelium dysfunctions related to the toxicity of chemo- and radiotherapy used in cancers, leukemias, and hematopoietic or organ transplantations. SACE is also of interest for monitoring arterial hypertension treated with specific synthetic ACE inhibitors.These various reasons for determining ACE activity have led to the development of numerous methods. The most widely used is the spectrophotometric assay using hippuryl-histidyl-leucine as substrate. Fluorimetric and radiochemical assays using both classic and novel substrates have been proposed, but they are time consuming, require special apparatus, and are not suited to automation. Kinetic spectrophotometry of furylacryloyl-phenylalanyl-glycyl-glycine hydrolysis is now used extensively because it is easy to automatize. Efforts are now required to standardize one or more of these assays. Indeed,“normal”plasma values differ not only according to the substrate, but also to the method of determination and to sex and age.

ISSN:1040-8363    

DOI:10.3109/10408369109106868

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractEntamoeba histolytica, the premier intestinal protozoan, has traversed time in its relentless quest for survival in its dichotomous role of parasite and pathogen. Enigmatic in its transition from human intestinal commensal to invader of human tissue, diverse in its pathogenicity for the human host, and intricate in its bacterial interrelationship in the bowel,E. histolytica, has become the focal point of intensive investigation in its basic biology underscoring human pathogenicity. This review will focus on facets of cell biology, pathophysiology, clinical, therapeutic, and epidemiologic, correlates, along with diagnostic modalities and future research trends.

ISSN:1040-8363    

DOI:10.3109/10408369109106869

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractLeukocyte-poor blood components (LPBC) have now become part of the armamentarium of available transfusable blood components. Indications for the use of LPBC vary in accordance with the underlying clinical condition, as well as the intended objectives of the transfusion therapy.Technological advances have made it possible to prepare LPBC using rather simple procedures. However, any manipulation of blood components and the additional use of filters, washing, rinsing solutions, etc. inevitably result in additional costs to the patient, the health-care institution, or third-party payers. Requests for LPBC involve the preparation of RBC or platelets, leuko-depleted by at least one log. Transfusion of LPBC must be done in a logical fashion that meets the needs of the patient. Currently, LPBC is indicated for patients with a history of nonhemolytic febrile transfusion reactions to delay alloimmunization to HLA antigens and avoidance of cytomegalovirus (CMV) infection.

ISSN:1040-8363    

DOI:10.3109/10408369109106870

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractBilirubin fractions are measured by (1) the direct diazo reaction, (2) high-performance liquid chromatography (HPLC), (3) direct spectrophotometry, and (4) enzymatic methods. HPLC, which effects separation and quantitation of the four bilirubin fractions, is the method of choice, but impractical for routine use. A special application of direct spectrophotometry allows the measurement of unconjugated bilirubin and the sum of bilirubin conjugates. This approach, which provides essentially the same information as HPLC, unfortunately is available only in one clinical analyzer. The direct diazo reaction measures bilirubin conjugates plusδ-bilirubin, albeit not very accurately. Direct diazo methods that measure unconjugated bilirubin as direct could obscure the clinical diagnosis. At acid pH, enzymatic methods measure all direct reacting bilirubins, while at pH 10 only conjugated bilirubins are measured. Because the measurement of conjugated bilirubins is clearly more helpful than that of direct bilirubin in the differential diagnosis of jaundice, direct diazo methods should be replaced by methods specific for bilirubin conjugates.

ISSN:1040-8363    

DOI:10.3109/10408369109106871

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractBilirubin fractions are measured by (1) the direct diazo reaction, (2) high-performance liquid chromatography (HPLC), (3) direct spectrophotometry, and (4) enzymatic methods. HPLC, which effects separation and quantitation of the four bilirubin fractions, is the method of choice, but impractical for routine use. A special application of direct spectrophotometry allows the measurement of unconjugated bilirubin and the sum of bilirubin conjugates. This approach, which provides essentially the same information as HPLC, unfortunately is available only in one clinical analyzer. The direct diazo reaction measures bilirubin conjugates plusδ-bilirubin, albeit not very accurately. Direct diazo methods that measure unconjugated bilirubin as direct could obscure the clinical diagnosis. At acid pH, enzymatic methods measure all direct reacting bilirubins, while at pH 10 only conjugated bilirubins are measured. Because the measurement of conjugated bilirubins is clearly more helpful than that of direct bilirubin in the differential diagnosis of jaundice, direct diazo methods should be replaced by methods specific for bilirubin conjugates.

ISSN:1040-8363    

DOI:10.3109/10408369109106872

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor

摘要:

AbstractThe American public has become aware that viral infections can be transmitted by blood transfusions; however, less attention has been paid to nonviral agents that are similarly transmitted. Although donors are tested routinely for serologic evidence ofTreponema palliduminfection (syphilis), there are no other bacterial infections for which donors are routinely tested, and no testing is done routinely to detect parasitic infections. Although current preventive strategies appear effective in preventing the transmission of nonviral agents by transfusion, changing population demographics, increased travel and immigration, and increased occurrence of certain asymptomatic bacterial infections in blood donors may require new policies to maintain the safety of the U.S. blood supply. This review focuses on the parasitic and bacterial infections that might pose a risk to transfusion recipients in the U.S.

ISSN:1040-8363    

DOI:10.3109/10408369109106873

出版商:Taylor&Francis    

年代:1991

数据来源: Taylor