357 research outputs found
Cyclic AMP metabolism and adenylate cyclase concentration in patients with advanced hepatic cirrhosis
Glucagon was tested for its effect on plasma adenosine 3âČ,5âČ-cyclic monophosphate (cyclic AMP), insulin, and glucose in healthy subjects and in patients with advanced cirrhosis of the liver. In the normal subjects, intravenous infusion of glucagon caused a significant increase in plasma cyclic AMP, glucose, and insulin. In advanced cirrhotics, plasma cyclic AMP, glucose, and insulin did not increase. Adenylate cyclase concentration was measured in liver tissue from end stage cirrhotic patients and from brain-dead organ donors whose cardiovascular function was maintained in a stable state. Basal and total adenylate cyclase concentration were not different in the two groups. Adenylate cyclase from the livers of advanced cirrhotics was, however, significantly less responsive to glucagon stimulation than was that from donor livers. Hepatocytes in advanced cirrhosis have abnormal metabolic behavior characterized by abnormal adenylate cyclase-cyclic AMP response to hormonal stimulation. © 1978
Trends of Earlier and Later Responses of C-peptide to Oral Glucose Challenges With Progression to Type 1 Diabetes in Diabetes Prevention TrialâType 1 Participants
ACTH-Bestimmungen im Plasma aus dem Bulbus cranialis venae jugularis
Der Anstieg der Corticosteroninkretion in das Nebennierenvenenblut frisch hypophysektomierter Ratten diente zur Bestimmung von ACTH-Spiegeln in 1 ml nativen, menschlichen Plasma. Normale ACTH-Plasmaspiegel sind sowohl bei Punktion der Vena cubitalis als auch des Bulbus cranialis venae jugularis durch diese Methode nicht oder nur ungenau zu erfassen. Bei Patienten mit pathologisch erhöhten ACTH-Spiegeln in der Vena cubitalis sind die ACTH-Spiegel im Bulbus cranialis venae jugularis signifikant höher. Es lieĂ sich eine Beziehung zwischen ACTH-Spiegel in der Peripherie (Vena cubitalis), Differenz der ACTH-Spiegel zwischen Bulbus cranialis venae jugularis und Vena cubitalis und biologischer Halbwertszeit von endogenem ACTH aufstellen. Nach den Ergebnissen der Bestimmung von ACTH-Spiegeln bei Nebennierengesunden lĂ€Ăt sich folgern, daĂ die biologische Halbwertszeit von endogenem ACTH gröĂer als 4 min sein muĂ. Bei Patienten mit erhöhten ACTH-Spiegeln lieĂ sich die biologische Halbwertszeit von endogenem ACTH gröĂenordnungsmĂ€Ăig mit ca. 40 min berechnen. Bei diesen Patienten betrug die mittlere tĂ€gliche ACTH-Inkretion ca. 100 E.ACTH-contents of 1 ml specimens of human plasma were assayed by measurement of increases of corticosterone output in the adrenal vein of acutely hypophysectomized rats. This procedure is not sensitive enough to measure normal ACTH-levels acurately, neither when blood was drawn from the bulbus cranialis venae jugularis, nor from the vena cubitalis. In patients having pathologically elevated ACTH-levels, the ACTH-content of plasma is significantly higher in the bulbus cranialis venae jugularis than in peripheral venous blood. An equation is presented formulating the relation of peripheral ACTH-levels, differences of ACTH-levels between bulbus cranialis venae jugularis and vena cubitalis, and of the biological halflife of endogenous ACTH. On the basis of the results of the determinations of socalled normal ACTH-levels it can be concluded, that the biological halflife of endogenous ACTH is longer than 4 min. From the data of patients with elevated ACTH-levels a halflife of approximately 40 min and a mean ACTH-secretion of approx. 100 units per day could be calculated
Disposable sensors in diagnostics, food and environmental monitoring
Disposable sensors are lowâcost and easyâtoâuse sensing devices intended for shortâterm or rapid singleâpoint measurements. The growing demand for fast, accessible, and reliable information in a vastly connected world makes disposable sensors increasingly important. The areas of application for such devices are numerous, ranging from pharmaceutical, agricultural, environmental, forensic, and food sciences to wearables and clinical diagnostics, especially in resourceâlimited settings. The capabilities of disposable sensors can extend beyond measuring traditional physical quantities (for example, temperature or pressure); they can provide critical chemical and biological information (chemoâ and biosensors) that can be digitized and made available to users and centralized/decentralized facilities for data storage, remotely. These features could pave the way for new classes of lowâcost systems for health, food, and environmental monitoring that can democratize sensing across the globe. Here, a brief insight into the materials and basics of sensors (methods of transduction, molecular recognition, and amplification) is provided followed by a comprehensive and critical overview of the disposable sensors currently used for medical diagnostics, food, and environmental analysis. Finally, views on how the field of disposable sensing devices will continue its evolution are discussed, including the future trends, challenges, and opportunities
Tolbutamide stimulation and inhibition of insulin release: Studies of the underlying ionic mechanisms in isolated rat islets
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