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Antarctic Marine Biodiversity: Adaptations, Environments and Responses to Change
Published in S. J. Hawkins, A. J. Evans, A. C. Dale, L. B. Firth, I. P. Smith, Oceanography and Marine Biology, 2018
All organisms grow. Growth of cells is mainly via, and ultimately dependent on, the synthesis of proteins both for structural and functional purposes and the retention of those proteins post synthesis. The total protein content of an organism is known as its protein pool, and this pool is dynamic with newly synthesised proteins adding to the pool, and degradation removing them. Changes in the total protein content of an organism is called protein growth. The combination of synthesis, degradation and growth is called protein metabolism (Fraser & Rogers 2007). Studies of protein metabolism and its components at low temperature have only been conducted for the last 20 years.
Effects of mercury graded doses on redox status, metallothionein levels and genotoxicity in the intestine of sea cucumber Holothuria forskali
Published in Chemistry and Ecology, 2019
Imen Rabeh, Khaoula Telahigue, Safa Bejaoui, Tarek Hajji, Lassaad Chouba, M’hamed EL Cafsi, Nejla Soudani
Furthermore, the increased generation of free radicals can also lead to protein modifications, giving rise to carbonyl group formation into side chains and/or reduction of sulphydryl groups in susceptible amino acids [44]. The occurrence of protein oxidative stress in the Hg-treated H.forskali intestine was confirmed by enhanced AOPP and PCO levels which reflected an excess of free radical generation and protein oxidative damages with a Hg graded dose. In this concern, Neto et al. [45] observed a significant increase in protein oxidation in hepatocytes of freshwater fish (Hoplias malabaricus) exposed to acute mercury doses. The Increase in PCO level indicates that protein metabolism is disrupted, resulting in accumulation of damaged molecules [46]. Moreover, proteins can be modified by direct attack of free radicals giving rise to carbonyl group formation into side chains and/to sulfhydryl groups reduction in amino acids [47].
Sustained transdermal delivery of human growth hormone from niosomal gel: in vitro and in vivo studies
Published in Journal of Biomaterials Science, Polymer Edition, 2022
Liming Wang, Lulu Wei, Wenbin Long, Quan Zhang, Yanhong Zou
Human growth hormone (hGH) produced in the pituitary gland regulates protein metabolism and stimulates growth [1]. It is widely used in the treatment of children’s growth disorder, turner syndrome, Prader-Willi syndrome, chronic renal insufficiency, etc [2, 3]. However, the current therapy need frequent subcutaneous injections due to short half-life, which leads to poor patient compliance [4]. The logistical issues with multiple subcutaneous injections (costly regime) and its associated pain lead to medication withdrawal and consequently failure in treatment [5]. Thus, there is considerable interest to overcome the issues associated with injections by seeking a non-invasive alternate route [6].
Cardiopulmonary parameters and organ blood flows for workers expressed in terms of VO2 for use in physiologically based toxicokinetic modeling
Published in Journal of Toxicology and Environmental Health, Part A, 2022
Pierre Brochu, Jessie Ménard, Sami Haddad
In the worst case scenario the accuracy of the oxygen uptake factors used for the conversion of E values (in kcal/min) into VO2 data (in L of O2/min) might vary −2 to – 1% (Brochu, Brodeur, and Krishnan 2011). Indirect calorimetry is the most accurate method (Bursztein 1989; Ferrannini 1988; Turell and Alexander 1964; Weir 1949) for determining E values in subjects at rest, a well as during physical activities based upon monitoring of gas exchange (i.e. VCO2 and VO2 in L/min) and nitrogen excretion from measurements in urine. The accuracy of indirect calorimetry measurements of E values varied from 0.6 to 0.7% by comparison with those measured by steady state direct calorimetry in a sealed chamber (or calorimeter) when urinary nitrogen excretions are considered in order to take into account the metabolism of proteins (Turell and Alexander 1964). The error ranges from +1 to +2%, when the correction for protein metabolism is not done. The doubly labeled water method (DLW) is based upon indirect calorimetry measurements and disappearance rates of oral doses of urinary water isotopes (2H2O and H218O) when combined for determination of total daily energy expenditures. The latter systematically encompasses voluntary and involuntary energy expended in unrestrained subjects each min of the day, 24-hr/day, on a daily basis during 7 to 21 days. In the worst-case scenario, simultaneous extreme mean errors for oxygen uptake factors (−2 to −1%), basal (+1 to +2%) and total daily energy expenditures (–1 to +3.3%) only affect E, VO2, Q, VE, VA values by −2.8 to +4% related to the aggregate daytime activities (Brochu, Brodeur, and Krishnan 2011).