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Nanobiosensors
Published in Vinod Kumar Khanna, Nanosensors, 2021
Deriving the advantage of specific recognition between antibody (Ab) and antigen (Ag), through Ab–Ag interaction, that forms the basis for immune response to infectious disease-causing agents, immunoassays are widely applied in clinical practice. AuNPs have been used in these assays because of their large surface area and biocompatibility. They provide higher loading density and greater retention of immunoactivity. House dust mites cause heavy atopic diseases, such as asthma and dermatitis. Among allergens (examples of antigenic proteins) from Dermatophagoides farinae, Der f2 shows the highest positive rate for atopic patients. Huang et al. (2006) assembled recombinant dust mite allergen Der f2 molecules on a AuNP-modified GP carbon electrode and used electrochemical impedance spectroscopy (EIS) to monitor the interaction between the allergen and murine monoclonal antibody (MAb). To make an EIS measurement, a small-amplitude signal, usually a voltage between 5 and 50 mV, is applied to a specimen over a range of frequencies in the range 10−3–105 Hz. The EIS instrument records the real (resistance) and imaginary (capacitance) components of the impedance response of the system.
Indoor Issues and Health Implications (and Ventilation Requirements)
Published in Rodger Edwards, Handbook of Domestic Ventilation, 2006
The house dust mite has long been established as a significant source of allergens. Voorhorst10 demonstrated that D. pteronyssinus derives its nutrition from human skin scales. These scales are steadily shed from the skins of human beings, and are, therefore, a major constituent of house dust. It is not the house dust mite itself that poses the risk to human health, but rather a substance found in its droppings. The Group I allergen widely referred to as Derp I has been shown by Taylor11 to act as a trigger of symptoms within those suffering from asthma. Figure 2.3 gives recommended maximum exposure concentrations for exposure to Derp I and house dust mites as recommended by the World Health Organisation (WHO). The lower concentrations must not be exceeded in order that sensitisation of subjects and the development of asthma itself are avoided. If the upper concentrations given are exceeded, then it would be expected that an acute asthma attack would be triggered in most patients who were already allergically sensitised to Derp I.
Allergens of Arthropods and Birds
Published in Harriet A. Burge, Bioaerosols, 2020
The phylum Arthropoda includes several species of organisms that are important in causing diseases via the indoor air. Of the nine classes of extant forms in the Arthropod phylum, the Hexapoda (or Insecta) and the Arachnids contain species that are known to produce proteins potentially allergenic to humans. Several species of the Arachnida class (the house dust mites) are primarily indoor organisms that require a controlled climate for growth and development and depend on mammalian hy-products for food. In most homes these organisms coexist with human inhabitants and are unnoticed. Members of the Hexapoda are generally outdoor organisms, some of which can be household pests.
Has a singular focus of building regulations created unhealthy homes?
Published in Architectural Science Review, 2020
Shruti Nath, Mark Dewsbury, Jeroen Douwes
In Tasmania, extensive studies have been conducted in the past deriving relations between house dampness, mould and concentrations of house dust mite allergens (Couper, Ponsonby, and Dwyer 1998; Ponsonby et al. 2000). In 1995, the average relative humidity in Tasmania during the summer was 66% and the winter value was 76% respectively (Couper, Ponsonby, and Dwyer 1998). Conducive environments for Der p 1 mite growth are ≈25°C and 75% relative humidity (Couper, Ponsonby, and Dwyer 1998). Der p 1 levels are associated with increased humidity and presence of moulds (Ponsonby et al. 2000). Home dampness is a major cause for increased allergen level in homes (Couper, Ponsonby, and Dwyer 1998). The house dust mite allergens are an important contributing factor in asthma and other allergies (Couper, Ponsonby, and Dwyer 1998; Dharmage et al. 1999; Garrett, Hooper, and Hooper 1998). Viitanen and Ojanen (2007), affirmed the risk of mould growth when the internal temperature is between 0°C and 50°C and the relative humidity is above 75%.
Prevalence of house dust mite allergens in low-income homes with evaporative coolers in a semiarid climate
Published in Archives of Environmental & Occupational Health, 2018
James D. Johnston, Taylor P. Barney, Justin H. Crandall, Marinn A. Brown, Tarah R. Westover, Sterling M. Paulson, Madeleine S. Smith, K. Scott Weber
House dust mite allergens are among the most clinically significant antigen exposures affecting humans, with medical outcomes including the development and exacerbation of asthma, allergic rhinitis, and atopic dermatitis.1–5 House dust mites acquire water primarily by absorbing it from humid air.6,7 The critical equilibrium humidity for dust mites to maintain water balance ranges from 55.0% to 75.0% RH at 15.0°C–35.0°C.6,8 Thus, mites are typically absent in arid and semiarid climates unless moisture is added to indoor air.
How clean is your house? A study of house dust mites, allergens and other contents of dust samples collected from households
Published in International Journal of Environmental Health Research, 2018
Lucy S. Casley, Tom Godec, James G. Logan, James C. Pearce, Hugh M. P. Smith, Sophie A. Stewart, Sarah Y. Dewhirst
The contents of household dust is highly variable and a range of constituents have been reported throughout the home, including dander, food matter, arthropods, hairs, chemicals, heavy metals, bacteria, fungi and mold (Zahradnik E. and Raulf M. 2014; Barberan et al. 2015; Amaro et al. 2016). Household dust is considered to be an important reservoir of indoor allergens, including those from cats, dogs and mites (Warner et al. 1990; Colloff et al. 1992; Zahradnik and Raulf 2014). Cat and dog allergens are not only present in the dander and hair from cats and dogs, but are also ubiquitous in the environments where these animals are present, even where you might not expect to find them, such as human hair (Siebers et al. 1998; Karlsson and Renstrom 2005; Liccardi et al. 2005; Krop et al. 2007). One of the most prevalent and clinically important source of indoor allergens comes from the scales and faecal pellets of various mite species (Erwin et al. 2005; Platts-Mills 2007; Zahradnik and Raulf 2014; Sanchez-Borges et al. 2017). Dermatophagoides pteronyssinus is an abundant house dust mite species found in houses in temperate regions (Arlian and Morgan 2003; Zock et al. 2006). This species releases high titres of the allergen Der p 1 into the environment, with particularly high levels where you find their main food source (human skin and fungi) (Zock et al. 2006).The optimal conditions for house dust mites are warm, moist locations and house dust mites have been observed in various locations within the car and home, such as children’s car seats, mattresses, pillows, carpets, sofas and soft toys (Binotti et al. 2005; Sun et al. 2014; Clarke et al. 2015b). The presence of other species of dust mites (Acari: Pyroglyphidae), storage mites (Acari: Acaridae, Glycyphagidae, Chortoglyphidae, Aeroglyphidae) and predatory mites (Acari: Cheyletidae) have also been reported in household dust, whereas D. pteronyssinus almost exclusively inhabits household dust (Arlian and Platts-Mills 2001; Arlian and Morgan 2003).