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Biological Monitoring: Neurophysiological and Behavioral Assessments
Published in Donald J. Ecobichon, Occupational Hazards of Pesticide Exposure, 2020
Characteristic of many pesticides including the organophosphorus and carbamate ester insecticides, some herbicides and fungicides have common symptoms such as muscle fasciculations, tremors, generalized muscle weakness (especially with exercise), diminished tendon reflexes, flaccid or rigid muscle tone, and paralysis, all of these signs pointing toward a neuronal site of action or one at the neuromuscular junction of the skeletal muscles. With the anticholinesterase-type insecticides, a further complication is associated with the respiratory muscles (both diaphragmatic and intercostal), resulting in weakness, paralysis, and compromised respiratory function (Ecobichon and Joy 1994). The pyrethroid esters and some organochlorine insecticides specifically affect the sensory nervous system. Almost all pesticides, at high levels of exposure, appear to elicit toxicity in the central nervous system (Ecobichon and Joy 1994). This spectrum of adverse health effects suggests that monitoring various components of the central and peripheral nervous systems would prove advantageous to detecting and quantifying the toxicity. However, given the broad range of “normal” values, major concerns center on whether the developed assays detect changes substantial enough to permit their use as screening tests for the clinical effects of exposures in groups of exposed individuals (Richter et al. 1992).
Basic Chemical Hazards to Human Health and Safety — I
Published in Jack Daugherty, Assessment of Chemical Exposures, 2020
A given amount of a chemical elicits a specific type and intensity of response. One person does not respond one way to a dose, X, and another person respond in a different way to the same dose. A slight variation may be noted in the degree of response, but the response will be the same. Dose-response is fundamental to toxicology, and the basis for comparing the harmfulness of one COC to another. The dose-response relationship is a consistent mathematical and biologically plausible correlation between the number of individuals responding and a known dose, over some exposure period. Table 3.12 lists the units of dose typically encountered in literature. The period of time over which the dose is administered is significant, and must be assumed, if not known or otherwise specified.The health risk due to exposure to noncarcinogens can be evaluated by comparing average daily dose (ADD) of a chemical with its corresponding acceptable daily intake (ADI) which is published by EPA: ADD=C×E×I where E is the exposure duration in hours. Noncarcinogens can cause such effects as mutagenicity, teratogenicity, reproductive system toxicity, and systemic toxicity. The latter group of health effects includes such target organs as the skin, eyes, central nervous system, peripheral nervous system, sensory nervous system, motor nervous system, respiratory system, blood and lymphatic systems, digestive system, the kidneys, the liver, the endocrine system, as discussed above.
Integration of Chinese and Western medicine in fainting during acupuncture treatment
Published in Artde D.K.T. Lam, Stephen D. Prior, Siu-Tsen Shen, Sheng-Joue Young, Liang-Wen Ji, Smart Science, Design & Technology, 2019
On the other hand, according to the World Health Organization (WHO), fainting during acupuncture treatment is defined as “an adverse reaction to acupuncture; a feeling of faintness, dizziness, nausea and cold sweating during and/or after needling, also called needle sickness” (Zhang, 1985). From the perspective of Western medicine, FDAT is a condition of functional disorder caused by strong stimulation of the peripheral sensory nervous system and influences the function of central nervous system and cardiac vascular system after needling. By assessing the symptoms of shock and reviewing the research on paled face, weak pulsation with tachycardia and hypotension, Western medicine regards shock as a form of physiological condition that exhibits the symptom of a suppressed circulatory system and subsequently turns into a pathological process that indicates insufficient body tissue perfusion. It can be divided into four types, namely hematogenic, cardiogenic, neurogenic and vasogenic. The compensatory mechanism triggered by the incidence of shock is mainly presented as increased cardiac output of the left ventricle to maintain the stability of arterial blood pressure, and increased heart rate as well as contracted peripheral blood vessels. Concurrently, the sympathetic nervous system is activated by the secretion of epinephrine and nor-epinephrine. Even though such compensatory mechanism might be beneficial during the early stage, when the heart rate increases excessively, the efficiency of cardiac pumping will ultimately decrease, and the function of vascular constriction might also lead to aggravation of the shock syndrome, such that the benign compensatory baro-receptor reflex gradually deteriorates into the acute symptom of severe vaso-vagal reflex.
Recent advances in neuromorphic transistors for artificial perception applications
Published in Science and Technology of Advanced Materials, 2023
Inspired by the supermodal sensory fusion in sensory nervous system, Wan et al. [48] developed a bimodal artificial sensory neuron (BASE) based on ionic/electronic hybrid neuromorphic electronic devices to implement the visual-haptic fusion, as schematically shown in Figure 22(a). The BASE collects optical and pressure information from photodetector and pressure sensors, respectively. Then, the bimodal information can be transmitted through an ionic cable. At last, information is integrated and induces post-synaptic currents on a synaptic transistor. Figure 22(b) shows the responses of the bimodal artificial sensory neuron to external stimuli. In addition, based on bimodal information sensory cues, sensory neurons can be stimulated at multiple levels to successfully simulate motion control, manipulating skeletal myotubes and a robotic hand, as shown in Figure 22(c). More interestingly, by simulating the multi-transparency pattern recognition task, the enhanced recognition ability realized on the fusion of visual/haptic cues is confirmed, as shown in Figure 22(d). The results show that the highly integrated perceptual system constructed by simulating sensory fusion at the neuron-level has far-reaching significances for neurorobotics and artificial intelligence.
Mechanism of peripheral nerve modulation and recent applications
Published in International Journal of Optomechatronics, 2021
Heejae Shin, Minseok Kang, Sanghoon Lee
The PNS is divided into the autonomic nervous system (ANS) that handles involuntary movements (heart rate, breathing, digestion, etc.) and the somatic nervous system (SNS) that controls voluntary responses (muscle contraction, etc.). The autonomic nervous system is again divided into the sympathetic nervous system and the parasympathetic nervous system (and the enteric nervous system). Since the ANS regulates the functions of organs such as the small intestine, the large intestine, and the heart, it is being targeted for the treatment of various diseases by implanting bioelectronics into the relevant nerves (e.g., vagus nerve[2–4]). The SNS is classified into the sensory nervous system responsible for afferent signals and the motor nervous system responsible for efferent signals. In the case of the somatic nervous system, because it controls muscles for the movements of arms and legs, many researchers are targeting those nerves to improve the function of the bionic limbs,[5–7] as well as for therapeutic purposes such as muscle rehabilitation.[8,9]
Vibrotactile sensitivity testing for occupational and disease-induce peripheral neuropathies
Published in Journal of Toxicology and Environmental Health, Part B, 2021
The peripheral sensory system is used by humans and animals to investigate and identify objects in their environment. Changes or loss of peripheral sensory perception may indicate the presence of disease or injury to 1) cutaneous sensory receptors; 2) peripheral nerves that carry sensory information from the site of stimulation to the dorsal root ganglia and/or spinal cord; 3) spinal afferent pathways that carry sensory information to the brain; and/or 4) regions of the brain involved in sensory perception (Hendry, Hsiao, and Bushnell 1999). Tests examining sensory perception, including tests of thermal perception, touch, two-point tactile discrimination, manual dexterity, nerve conduction velocity, and perception of vibration, have been used to assess sensory loss in workers exposed to hand- or foot-transmitted vibrations (Cherniack et al. 2008, 1990; Cole et al. 1998; Poole, Mason, and Harding 2016; Seah and Griffin 2008) or workers exposed to various chemicals, such as pesticides (Dicka et al. 2001; Starks et al. 2012; Steenland et al. 1984) Other investigators also reported that sensitivity to vibrotactile stimuli is altered in the hands and feet as a result of aging (Brammer, Taylor, and Lundborg 1987; Peterson et al. 2020), and various diseases including diabetes (Ising, Dahlin, and Larsson 2018; Peterson et al. 2020) and stroke (Liu et al. 2002). In contrast, very low-amplitude vibration may be able to be used to improve sensory perception in subjects with balance problems and various movement disorders (Bao et al. 2019; Liu et al. 2002). This review summarizes how, and under which conditions, the vibrotactile perception threshold (VPT) test has been used to detect injury or dysfunction of the sensory nervous system (Brammer et al. 2010).