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Sarcopenia is a systemic skeletal muscle disease characterized by a decline in skeletal muscle mass and function. Originally defined as an age‐associated condition, sarcopenia presently also encompasses muscular atrophy due to various pathological factors, such as intensive care unit‐acquired weakness, inactivity, and malnutrition. The exact pathogenesis of sarcopenia is still unknown; herein, we review the pathological roles of the neuromuscular junction and mitochondria in this condition. Sarcopenia is caused by complex and interdependent pathophysiological mechanisms, including aging, neuromuscular junction impairment, mitochondrial dysfunction, insulin resistance, lipotoxicity, endocrine factors, oxidative stress, and inflammation. Among these, neuromuscular junction instability and mitochondrial dysfunction are particularly significant. Dysfunction in neuromuscular junction can lead to muscle weakness or paralysis. Mitochondria, which are plentiful in neurons and muscle fibers, play an important role in neuromuscular junction transmission. Therefore, impairments in both mitochondria and neuromuscular junction may be one of the key pathophysiological mechanisms leading to sarcopenia. Moreover, this article explores the structural and functional alterations in the neuromuscular junction and mitochondria in sarcopenia, suggesting that a deeper understanding of these changes could provide valuable insights for the prevention or treatment of sarcopenia. [ABSTRACT FROM AUTHOR]

A sensitive flow injection (FI) chemiluminescence (CL) method was developed for the determination of trace amounts of progesterone. This method was based on the luminescent properties of the tris(1,10-phenanthroline) ruthenium(II) - potassium permanganate (KMnO4) - progesterone in acidic medium sensitized by Na2SO3. With the peak height as a quantitative parameter applying optimum conditions, the relative CL intensity was linear with progesterone concentration in the range of 1.0 × 10−10 ∼ 6.0 × 10−9 g·ml−1 and 6.0 × 10−9 ∼ 4.0 × 10−8 g·ml−1 with a detection limit of 7.1 × 10−11 g·ml−1. The relative standard deviation (RSD) was 2.79% for 1.0 × 10−8 g·ml−1 progesterone ( n = 11). The proposed method held low detection limit and was successfully applied to determination of progesterone in pharmaceutical preparations. The possible CL reaction mechanism was also discussed. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Chemiluminescence (CL) detection for the determination of estrogen benzoate, using the reaction of tris(1,10-phenanthroline)ruthenium(II)-Na2SO3-permanganate, is described. This method is based on the CL reaction of estrogen benzoate (EB) with acidic potassium permanganate and tris(1,10-phenanthroline)ruthenium(II). The CL intensity is greatly enhanced when Na2SO3 is added. After optimization of the different experimental parameters, a calibration graph for estrogen benzoate is linear in the range 0.05-10 µg/mL. The 3 s limit of detection is 0.024 µg/mL and the relative standard deviation was 1.3% for 1.0 µg/mL estrogen benzoate ( n = 11). This proposed method was successfully applied to commercial injection samples and emulsion cosmetics. The mechanism of CL reaction was also studied. Copyright © 2011 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Nucleic acid can greatly enhance the fluorescence intensity of quercetin in HMTA-HCl (pH 5.5) buffer. The enhanced intensity is in proportion to the concentration of nucleic acids in the range 5.0 × 10−9 to 1.0 × 10−6 g/mL for fsDNA, 5.0 × 10−9 to 7.0 × 10−7 g/mL for ctDNA and 5.0 × 10−9 to 1.0 × 10−6 g/mL for yRNA, and their detection limits (S/N = 3) are 3.5 × 10−9, 7.8 × 10−10 and 2.6 × 10−9 g/mL, respectively. In comparison with most reported fluorescent probes for the determination of nucleic acids, the proposed probe has higher sensitivity and lower toxicity. The interaction investigation indicates that quercetin binds with double-strand DNA in groove binding mode, resulting in fluorescence enhancement of this system. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

It was found that the fluorescence of Tb3+-epinephrine (E) complex can be enhanced by both bovine serum albumin (BSA) and sodium dodecylsulfate (SDS), and stabilized by ascorbic acid (AA). It is considered that the fluorescence enhancement of the Tb3+-E-BSA-AA-SDS system originates not only from the hydrophobic microenvironment provided by BSA-SDS, but also from the energy transfer from BSA to Tb3+ in this system. Therefore, a new fluorescence method for the determination of protein concentrations as low as 1.3 × 10−9 g mL−1 BSA is established using Tb3+-epinephrine complex as probe. The method has been applied for the determination of BSA and human serum albumin in actual samples, and the results obtained are satisfactory. Compared with other fluorescence methods, this method is simpler and more sensitive for the determination of protein. The mechanism of the fluorescence enhancement of the system is studied in detail. Copyright © 2009 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this paper, a sensitive resonance light scattering (RLS) method for the determination of protein is reported. In the Tris-HCl (pH 7.50) buffer, protein enhanced the RLS intensity of the Y3+-2-thenoyltrifluoroacetone (TTA)-sodium dodecyl sulphate (SLS) system. The enhanced RLS intensities were in proportion to the concentrations of proteins in the range 8.0 × 10−9-1.0 × 10−5 g/mL for BSA, 1.0 × 10-8-1.0 × 10−5 g/mL for HSA and 1.0 × 10-8-1.0 × 10−6 g/mL for EA, and their detection limits were 5.0, 5.4 and 6.7 ng/mL, respectively. Actual samples were satisfactorily determined. The interaction mechanism was also studied. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Experiments indicated that nucleic acids can quench the fluorescence of the Eu3+-2-thenoyltrifluoroacetone (TTA)-1,10-phenanthroline (Phen) system. Based on this, a sensitive method for the determination of nucleic acids was proposed. The experiments indicated that under the optimum conditions, the quenched fluorescence intensity was in proportion to the concentration of nucleic acids in the range 1.0 × 10−11-1.0 × 10−6 g/mL for yeast RNA (yRNA), 5.0 × 10−11-5.0 × 10−7 g/mL for fish sperm (fsDNA) and 1.0 × 10−10-1.5 × 10−6 g/mL for calf thymus DNA (ctDNA). Their detection limits were 3.0 × 10−12, 4.0 × 10−12 and 5.0 × 10−11 g/mL, respectively. Therefore, the proposed method is one of the most sensitive methods available. The interaction between nucleic acids and Eu3+-TTA-Phen is also discussed. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The fluorescence of acridine orange (AO) is greatly quenched by the anionic surfactant sodium dodecyl benzene sulphonate (SDBS), but when protein is added into the AO-SDBS system, the fluorescence intensity of the latter is enhanced again. Based on this, a new fluorimetric method of determination of protein was developed. Under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of protein, such as bovine serum albumin (BSA), human serum albumin (HSA) and egg albumin (EA), over a wide range with detection limits at the 10−9 g/mL level. This method has been satisfactorily used for the determination of protein in samples. We compared results using 280 nm and 490 nm excitation wavelengths and the mechanism of the assay. Copyright © 2006 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Resonance light scattering (RLS) of Congo red (CR) was greatly enhanced by BSA (HSA) in the presence of Triton X-100 (TX-100). In sodium citrate-HCl buffer (pH 2.7-3.0), the enhanced intensity of resonance light scattering at 360 nm was in proportion to the concentration. The linear relationship was obtained between the resonance light scattering intensity and proteins in the range 5.0 × 10−8-8.0 × 10−6 g/mL and 1.0 × 10−9-6.0 × 10−6 g/mL for BSA and HSA, respectively. Their detection limits were 1.4 × 10−8 g/mL and 2.8 × 10−10 g/mL (S:N = 3), respectively. Synthetic and actual samples were analysed satisfactorily. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The fluorescence intensity of the morin-Al3+ complex was greatly enhanced by proteins in the presence of sodium dodecyl benzene sulphonate (SDBS). Based on this, a new fluorimetric method for the determination of protein was developed. Under optimum conditions, the enhanced intensity of fluorescence was in proportion to the concentration of proteins in the range 1.0 × 10−8-1.3 × 10−5 g/mL for bovine serum albumin (BSA), 4.0 × 10−8-1.2 × 10−5 g/mL for egg albumin (EA) and 5.0 × 10−8-1.2 × 10−5 g/mL for human serum albumin (HSA). Their detection limits (S:N = 3) were 5.0 × 10−9, 1.8 × 10−8 and 1.6 × 10−8 g/mL, respectively. The interaction mechanism was also studied. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

A novel and stable fluorimetric method was established for the determination of nucleic acids. The proposed method is based on the reduction by nucleic acids of Ce(IV) to fluorescent Ce(III). The fluorescence intensity can be greatly increased by sodium triphosphate. The enhanced fluorescence intensity is proportional to the concentration of nucleic acids in the range 4.2 × 10−8-4.2 × 10−6 g[sol ]mL for fish sperm DNA and 5.0 × 10−8-6.5 × 10−6 g[sol ]mL for yeast RNA, and the detection limits (S[sol ]N _ 3) are 13.5 ng[sol ]mL and 45 ng[sol ]mL, respectively. The reaction mechanism of the hydrolytic scission of nucleic acids by Ce(IV) is discussed. Copyright © 2005 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Chlorotetracycline (CTC) can react with europium ions Eu3+, and the complex emits the intrinsic fluorescence of Eu3+. The intensity is greatly enhanced by proteins and this forms the basis of a new fluorimetric method for determination of protein. Further research indicates that under optimum conditions, the enhanced intensity of fluorescence is in proportion to the concentration of proteins, in the range 2.0 × 10−7-1.0 × 10−5 g/mL for bovine serum albumin (BSA) (linear equation, If = 34.35933 + 11.54467 × 106C)( r = 0.99895) and 8.0 × 10−7-1.0 × 10−5 g/mL for human serum albumin (HSA) (linear equation, If = 76.58881 + 5.3569 × 106C) ( r = 0.99283). Detection limits (S/N = 3) were 8.9 × 10−9 g/mL for BSA and 3.3 × 10−8 g/mL for HSA. In an assay for BSA in calf serum, this method gave a value close to that determined by the UV spectrophotometric method. Copyright © 2004 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]