PK/TK Analysis of Continuous Zero-Order Exposure to Xenobiotics (Intravenous Infusion)
Mehdi Boroujerdi in Pharmacokinetics and Toxicokinetics, 2015
The zero-order input in this chapter refers to the administration of solution with known concentration of a compound into the systemic circulation via intravenous administration over a period of time. Thus, the input is not instantaneous, as was discussed in Chapter 10, and the constant rate of input is considered zero-order kinetics. The specialized infusions through routes of administration such as epidural or intrathecal are not a part of this discussion. Intravenous infusion is used commonly to treat illnesses that require long-term exposure and duration of action, or when the administration of bolus dose can be hazardous to the human subject or experimental animals. Often the long-term exposure to organic solvents that can absorb through inhalation and enter the systemic circulation without impediment can also be considered zero-order input. An intravenous infusion requires that the compound remains stable and soluble in the solution, and tolerable by the subject. The vehicles are usually solutions containing water of highest purity and sterility with dextrose, saline or other specialized additives and/or medications.
The Heart as a Pump
Uri Dinnar in Cardiovascular Fluid Dynamics, 2019
This chapter discusses the heart, and especially the left ventricle, by considering its pumping activity. The heart, composed of two atria and two ventricles, is a combination of two synchronized pulsatile pumps in series. The performance of the heart can be measured and characterized by the use of various mechanisms that contribute to its function. In an attempt to find suitable parameters for left ventricular performance, cardiologists have moved from values that relate only to blood pressure in the systemic circulation to values that combine blood pressure in the ventricle and in the systemic circulation with volumes of blood pumped by the heart. The hydrodynamic parameters include both flow conditions, in both ventricles and the aorta, and flow characteristics, mainly velocity. When the mechanical descriptors used are force, velocity, and length, the underlying assumption is a unidimensional performance of the cardiac muscle.
Lymphatic Transport After Parenteral Drug Administration
William N. Charman, Valentino J. Stella in Lymphatic Transport of Drugs, 2019
This chapter aims to review the different aspects of lymphatic drug delivery which have employed macromolecular carrier systems after local parenteral administration. The primary emphasis is on the work carried out at Kyoto University although other literature examples. In order to effectively study the lymphatic transport of drugs after parenteral administration, it is necessary to choose an appropriate experimental system. Generally, the lymphatic transport of a drug is evaluated by measuring the time-dependent concentration changes in lymph after administration. Drug concentration profiles in the lymph nodes can also be used for the evaluation of lymphatic transport after parenteral administration. Lymphatic transport of drugs is often observed after intravenous administration since drugs administered directly into the systemic circulation may transfer to the lymphatic system after distribution to peripheral tissues. Lymphatic transfer after intravenous injection is much less efficient than direct lymphatic transport after administration as a topical injection.
The spectrum study of blood pressure during the disturbance of organic vascular beds
Published in Journal of the Chinese Institute of Engineers, 1989
Shuenn Young, Wei Wang, Luke Chang, Te Kuo
Like electrical circuit components, the vascular beds in organs present impedance to waves in systemic circulation. In this study, the authors design an animal experiment to study the effect of the impedance to the pressure waves. We view the systemic circulation as an electrical circuit network, and interpret the vascular beds in organs as lumped components in the electrical circuit. Nature's designing of the systemic circulation minimizes the pressure wave reflection, and maximizes blood distribution. This is very similar to the concept adopted by electrical engineers in designing electrical circuits.
Evidence of Cellular Supplies to the Endolymphatic Sac from the Systemic Circulation
Published in Acta Oto-Laryngologica, 1995
Hiroshi Iwai, Koichi Tomoda, Muneo Inaba, Nobuo Kubo, Satoshi Tsujikawa, Susumu Ikehara, Toshio Yamashita
Donor T lymphocytes injected into the host systemic circulation were observed to infiltrate into the host endolymphatic sac in mice. These findings suggest that the endolymphatic sac, a major immune organ in the inner ear, is supplied with immunocompetent cells from the systemic circulation. This concept is consistent with clinical reports that inner ear disorders accompany certain systemic autoimmune diseases. Bone marrow transplantation to replace autoreactive immunocompetent cells with normal cells should be considered as a potential therapy for inner ear autoimmune diseases and an alternative to conventional treatments.
In Vivo Microscopy of the Liver after Injection of Lipiodol into the Hepatic Artery and Portal Vein in the Rat
Published in Acta Radiologica, 1989
Zuxing Kan, K. Ivancev, I. Hägerstrand, V. P. Chuang, A. Lunderquist
The route, distribution and clearance of intraarterially administered Lipiodol in the liver has been the subject of much speculation. The hepatic microcirculation was therefore studied by in vivo microscopy after injection of Lipiodol into the hepatic artery and the portal vein in rats. After intraarterial injection, Lipiodol rapidly entered the portal branches through arterio-portal communications. Lipiodol also passed through the sinusoids from the portal into the hepatic veins and then into the systemic circulation. Sinusoidal congestion occurred when the oil droplets filled the liver microcirculation and resolved as the oil was cleared. It is of clinical significance to note the passage of the oil into the systemic circulation after arterial injection.
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