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Cardiovascular and Other Illnesses Caused by Diesel Fuel Exhaust Emissions
Published in Ozcan Konur, Petrodiesel Fuels, 2021
Mills et al. (2011) study the adverse in vivo vascular effects of DE inhalation in a paper with 99 citations. They focused on the role of combustion-derived nanoparticles in mediating the adverse cardiovascular effects of air pollution. They exposed 16 healthy volunteers to dilute DE, pure carbon nanoparticulate, filtered DE, or FA. Following each exposure, they measured forearm blood flow during intrabrachial bradykinin, acetylcholine, sodium nitroprusside, and verapamil infusions. They found that compared with FA, inhalation of DE increased systolic blood pressure and attenuated vasodilatation to bradykinin, acetylcholine, and sodium nitroprusside. Exposure to pure carbon nanoparticulate or filtered exhaust had no effect on endothelium-dependent or independent vasodilatation. To determine the direct vascular effects of nanoparticulates, they assessed isolated rat aortic rings (n = 6–9 per group) in vitro by wire myography and exposed to DE particulate, pure carbon nanoparticulates. Compared with vehicle, DE particulate (but not pure carbon nanoparticulate) attenuated both acetylcholine and sodium-nitroprusside-induced vasorelaxation. These effects were partially attributable to both soluble and insoluble components of the particulate. They conclude that combustion-derived nanoparticulate predominately mediate the adverse vascular effects of DE inhalation.
Special Types of Closed-Loop Drug Input Controllers
Published in Robert B. Northrop, Endogenous and Exogenous Regulation and Control of Physiological Systems, 2020
The design of closed-loop drug delivery systems presents a special challenge to the biomedical control engineer. The plant parameters often vary markedly in value between individuals, so that individual plant identification is often necessary to achieve accurate control of drug levels. Plant parameters are often nonstationary; the drug itself can alter the physiological states of organs that are involved in a drug’s breakdown and elimination. For example, cancer antimetabolites can poison liver cells and/or kidney cells, as well as kill tumor cells. The plants are nonlinear; drugs can be injected, but not uninjected. Excess drug is generally cleared from the body passively, by natural means. Also, the turn-on (step) response of a compartmental pharmacokinetic/physiological (CPK/P) system must show little specified overshoot (or undershoot). This is especially true with blood-pressure-lowering drugs like sodium nitroprusside. The mean arterial pressure must ramp down smoothly to the set point and not shoot past it at system turn-on. Otherwise the patient could faint or go into shock.
Multiple Model Adaptive Control
Published in Roderick Murray-Smith, Tor Arne Johansen, Multiple Model Approaches to Modelling and Control, 2020
Kevin D. Schott, B. Wayne Bequette
An area which has had many experimental applications of MMAC is drug infusion control. He et al. (1986) apply MMAC via simulation and animal experiments to the control of blood pressure in dogs by controlling the infusion rate of nitroprusside. Their model bank consists of eight transfer function models and the controller bank consists of eight PI controllers, each based on one of the models. The models all have the same dynamic characteristics with different gains. The model gains are selected so that the corresponding controller would satisfy phase margin requirements for each model interval. Martin et al. (1987) combine pole-placement, a Smith predictor and PI control into an MMAC framework for blood pressure control using nitroprusside. The control strategy is applied to a nonlinear simulation model. MMAC-PI is used by Yu et al. (1987) to control arterial oxygen by adjusting the inspired oxygen fraction in mechanically ventilated dogs.
Computational modeling of inhibitory signal transduction in urinary bladder PDGFRα+ cells
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2023
Amritanshu Gupta, Rohit Manchanda
In animal models, it has been demonstrated that nitric oxide (NO) induces dSMC relaxation, and the application of nitric oxide synthase (NOS) inhibitors reduced detrusor contractions (Mumtaz et al. 2000; Mamas et al. 2003). NO acts in target tissues via the nitric oxide-soluble guanyl cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) pathway. However, in isolated guinea pig bladder preparations, the application of the NO donor sodium nitroprusside did not raise cyclic guanosine monophosphate (cGMP) levels in the dSMCs suggesting the involvement of an indirect pathway for mediation of NO-induced relaxation (Gillespie and Drake 2004). This indirect pathway could be via NO action on PDGFRα+ cells, which express the nitric oxide sensitive soluble guanylyl cyclase (NO-sGC) and exhibit intense cGMP immunoreactivity (Blair et al. 2014).
Bio-inspired multifunctional zinc oxide nanoparticles by leaf extract of Andrographis serpilifolia and their enhanced antioxidant, antimicrobial, and antidiabetic activity—a 3-in-1 system
Published in Particulate Science and Technology, 2022
Venkata S. Kotakadi, Susmila Aparna Gaddam, Peddana Kotha, Rajesekhar Allagadda, Appa Rao Ch., Sai Gopal D. V. R.
Nitric oxide scavenging activity of A. serpyllifolia leaf extract and As-ZnONPs at different concentrations of 25, 50, 75, and 100 µg/ml was measured by a slightly modified method of (Mosmann 1983). Nitric oxide radicals (NO) were generated from sodium nitroprusside. 1 ml of sodium nitroprusside (10 mM) and 1.5 ml of phosphate buffer saline (0.2 M, pH 7.4) were added to different concentrations 25, 50, 75, and 100 µg/ml of A. serpyllifolia leaf extract and As-ZnONPs and incubated for 150 min at 25 °C and 1 ml of the reaction mixture was treated with 1 ml of Griess reagent (1% sulfanilamide, 2% H3PO4 and 0.1% naphthyl ethylene diamine dihydrochloride). The absorbance of the chromatophore was measured at 546 nm. Nitric oxide scavenging activity was calculated using the above equation (DPPH method).
Importance and use of pulse oximeter in COVID-19 pandemic: general factors affecting the sensitivity of pulse oximeter
Published in Indian Chemical Engineer, 2020
Kirtikumar C. Badgujar, Ashish B. Badgujar, Dipak V. Dhangar, Vivek C. Badgujar
Haemoglobin and methemoglobin have nearly similar absorption, whereas methemoglobin exists in blood at relatively lower concentration (∼ 1 % or < 1 %) which attributed insignificantly in pulse oximeter. However, some drugs like vasodialators or vasoconstrictors may change the concentration of methemoglobin which may give pseudo readings [42]. Drugs, such as nitroglycerine and sodium nitroprusside, act as vasodialators (decrease the blood pressure) showed metabolism of sodium nitroprusside drugs in RBCs which is attributed to give an abnormal value of oxygen saturation [30] (Table 1 entries 73–76). Nitroprusside drug reacts with the haemoglobin which generates methemoglobin and highly unstable radical nitroprusside which rapidly decomposes to release five cyanide ions to form cyanmethemoglobulin which produces pseudo reading [30]. The drug, which increases the bilirubin level, may have marginal influence on the pulse oximeter reading. Thus, in general, oxygen saturation value determined by the pulse oximeter is varied by hypothermia and hyperthermia induced by peripheral vasoconstriction and vasodilating drugs.