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Biosensors for Disease Diagnosis
Published in Ayodeji Olalekan Salau, Shruti Jain, Meenakshi Sood, Computational Intelligence and Data Sciences, 2022
Ramneet Kaur, Dibita Mandal, Juveria Ansari, Prachi R. Londhe, Vedika Potdar, Vishakkha Dash
Immunosensors are biological sensors in which there is an interaction between antibodies and antigens. Upon contact of the host with an antigen, lymphocyte B produces the antibody. Following the apoptosis of effector lymphocytes and memory B cells, the antigens are eliminated. Enzymatic biosensors use bio-recognition, the catalytic property of enzymes or molecules with high chemical specificity and efficient selectivity for the target substrate. The DNA biosensors or genosensor discriminate between organisms and detect various diseases and human pathogens through specific nucleic acid sequences. Whole cells act as recognition elements. Surface antigens present on the cell envelopes serve as targets for bio-recognition [14]. The platform for the detection of SARS-CoV-2 is based on three important aspects, which include the targets which are viral RNA, proteins or human immunoglobulins; the identification methods which are based on aptamers, antibodies, nucleic acid probes or receptors; and the amplification of signals and transduction systems based on electrical signals, surface plasmon resonance and fluorescent signals [15].
Ultrastructural Immunocytochemistry
Published in Joan Gil, Models of Lung Disease, 2020
Samuel S. Spicer, Bradley A. Schulte
As one of its major goals, the cytochemical approach seeks advantage over conventional biochemical analysis in demonstrating the precise location of a specific tissue component. Histochemical methods suffered in the past in comparison to those of biochemistry in their limited chemical specificity. However, histochemistry’s aim of localizing specific entities has been realized with im-munocytochemistry. In fact, with monoclonal antibodies immunocytochemistry advances a step farther, by differentiating segments (epitopes) of the peptide backbone or saccharide side chains within a protein or glycoprotein antigen. Im-munostaining thus demonstrates in situ differences in expression of the same gene in different species, as evidenced by immunostaining of human but not rodent kidney with monoclonal antibody to human Tamm Horsefall protein (unpublished observation).
Gastrointestinal Tract as a Major Route of Pharmaceutical Administration
Published in Shayne C. Gad, Toxicology of the Gastrointestinal Tract, 2018
This type of transport shows low chemical specificity and does not involve a carrier or the expenditure of energy. The process involves the absorption of a substance across a concentration gradient from a membrane compartment of high concentration to a compartment of low concentration. Diffusion only occurs when there is a concentration gradient of a substance separated by a membrane. The physics of diffusion follows Fick’s first law of diffusion which describes the passive movement down a concentration gradient to equilibrate the substance in both compartments. Given enough time, the flow of substance will eventually result in homogeneity within the matrix, causing the net flow of substances to cease. Fick postulated that the flux of material across a given plane is proportional to the concentration gradient across the plane (Guenneau and Puvirajesinghe, 2013; Zhou et al., 2015). Mathematically this movement is described by the following equation:
Mass spectrometry imaging: How will it affect clinical research in the future?
Published in Expert Review of Proteomics, 2018
Marialaura Dilillo, Bram Heijs, Liam A. McDonnell
Recent years have witnessed rapid developments in methodology and technology that have increased the number of molecular classes amenable to MSI, currently MSI can be used to measure metabolites [9,10], lipids [11], glycolipids [12], drugs (and their metabolites) [13], glycans [14], peptides [15], and proteins [16], including semi-targeted analysis of extra-cellular matrix proteins [17].increased the spatial resolution for improved cellular specificity [18,19].increased the mass resolution for improved chemical specificity [20,21].Data-dependent MS/MS-based workflows also now enable in-situ identification of molecules of interest [22].increased the accessibility of powerful bioinformatics tools for automated molecular annotation and histological interpretation of the data [23].
Simultaneous targeting therapy for lung metastasis and breast tumor by blocking the NF-κB signaling pathway using Celastrol-loaded micelles
Published in Drug Delivery, 2018
Yue Zhao, Yanan Tan, Tingting Meng, Xuan Liu, Yun Zhu, Yun Hong, Xiqin Yang, Hong Yuan, Xuan Huang, Fuqiang Hu
Most deaths from breast tumor are due to metastatic disease (O'Flanagan et al., 2017) and the five-year survival rate for advanced or metastasized breast tumor is only 26%. For many patients, metastasis has already occurred when tumor is detected (Klein, 2009; Ullah et al., 2017). If only treatment is given for primary tumor, metastasis may not be controlled, which may eventually result in treatment failure. Tumor cells invade over the barrier of degraded extra cellular matrix (ECM) via secreting matrix metalloproteinases (MMPs), which allows tumor cells to move forward (Valastyan & Weinberg, 2011; Zhu et al., 2012). Consequently tumor cells enter the bloodstream and a few lodge in distant organs such as the lungs (Woodhouse et al., 1997; Bonotto et al., 2014). Metastases acts as a biobarriers due to their smaller size, higher dispersion to organs, and lower vascularization than primary tumors, which make them less accessible to molecular drug (Nacev et al., 2011). However, metastatic lesions can upregulate specific cell-surface molecules and secreted factors that differ from the rest of its host organ (Ahmed & Douek, 2013). If the appropriate chemical specificity is selected, targeted micelles could provide a unique opportunity for therapeutic compounds to metastases and primary tumor.
Strong ions and charge-balance
Published in Scandinavian Journal of Clinical and Laboratory Investigation, 2023
Before considering in a broader sense the attractive aspects of separating in the modeling between weak and strong ions, it is reasonable to consider some differences between the charge-balance model as we have developed it [15] and the physicochemical approach of Stewart [7]. The obvious similarity between these approaches is that both build directly on the formal statement of charge balance as it can be derived from basic physical chemistry. Now, the physicochemical approach provides simplifications of weak acids in order to facilitate the clinical utility whereas our model attempts to approach chemical specificity as much as possible. It is certainly true that no biological fluid can ever be completely described, but the charge-balance model allows for estimating the consequences of explicit misspecifications and thereby makes it possible to calibrate the results. Hence, in the series of clinical data from Pittsburgh [12] we could calculate how much charge on weak ions or strong ions was unaccounted for. Also, the common reproach [35] that the constituents of SID may be indistinct since, as an example, lactate may be strong or weak depending on where pH is compared to pKa of 3.86, is easily dismissed since if in doubt we make no error by modeling as a weak acid. The major issue, however, concerns the dichotomization of Stewart [8] between independent and dependent variables. Importantly this concept is not required for the derivation of the model and assumes the position of a completely external, additional attribute. In contrast, for our general charge-balance model, all we have is the expression of charge-balance since it embodies all we know and, interestingly, all we need to know to understand the system. Whether for instance, SID or [H+] is a dependent or independent value is not determined by some underlying ontological essence but entirely by the question asked to the model. As an example, in the rabbit CCD proton secretion secondarily causes Cl- secretion to balance charge [36], so here proton concentration is the independent variable and SID the dependent variable. Also, when deriving the pH-dependent buffer capacity according to Van Slyke [16], SID is expressed as a function of the weak ions and then differentiated [15]. On the other hand, in many clinical or experimental situations, the additivity of strong ions is employed to derive the results, treating SID components as independent variables. True, this requires specification of an explicit compartmental model, but this will be the case for any coherent model that could eventually be proposed. We have seen some consequences of ignoring SID and thereby sabotaging electroneutrality, so even though charge-balance modeling may be laborious it is probably the way to go if we want to understand acid-base.