Gluconic acid aqueous solution: A bio-based catalytic medium for organic synthesis

Gluconic acid is non-toxic, non-volatile, non-corrosive, and easily biodegradable chemical, which can be produced from biomass using several methods: oxidation by molecular oxygen using heterogeneous catalysis, enzymatic oxidation, and microbial fermentation. Being highly soluble in water, gluconic acid can form concentrated aqueous solutions, and its 50% aqueous solution has found application as a catalytic medium for organic synthesis. For some reactions, gluconic acid aqueous solutions (GAAS) outperform conventional and green solvents when used as media for organic synthesis. GAAS was found to be particularly efficient in the Knoevenagel condensation, the Michael addition, and multicomponent reactions based on them. These and other chemical transformations utilizing GAAS as a medium are discussed in this review. We also compare the effectiveness of GAAS as a new green catalytic medium and the performance of other solvents and catalysts.     

Estrogen-like neuroprotection of isopsoralen against spinal cord injury through estrogen receptor ERα

Metabolic Brain Disease - Isopsoralen is a type of furocoumarin that exhibits estrogen-like activities. The aim of this study was to determine the estrogen-like neuroprotection of isopsoralen in an...     

Hepatoprotective effect of chitosan-caffeic acid conjugate against ethanol-treated mice

The chitosan-caffeic acid (CCA) conjugate shows a hepatoprotective effect against oxidative stress-induced hepatic damage in cultured hepatocytes. The objective of this study is the verification of the hepatoprotective effect of the CCA in vivo against ethanol-induced liver injury in mice. The administration of ethanol resulted in the increase of the serum-aminotransferase activities (AST and ALT), triglycerides, total cholesterol, and lipid peroxidation. The CCA co-administration, however, significantly (p < 0.05) ameliorated these serum biomarkers. The antioxidant-enzyme activities in the liver tissue, including those of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx), were significantly decreased by a chronic ethanol administration, whereas the hepatic lipid-peroxidation level was increased. Moreover, the chronic ethanol administration elevated the gene expression of pro-inflammatory cytokines such as tumor-necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the liver tissue. The CCA co-administration, however, significantly (p < 0.05) increased the activities of the SOD, CAT, and GPx and caused the down-regulation of the TNF-α- and IL-6-gene expressions in the liver tissue. An histopathologic evaluation also supported the hepatoprotective effect of the CCA against ethanol-induced hepatotoxicity in the mice.     

Polymyositis associated with hypothyroidism or hyperthyroidism: two cases and review of the literature

Studies confirming a possible relationship of polymyositis within thyroid dysfunction, either hypothyroidism or hyperthyroidism, are hardly available. To define the association, identify clinical, laboratory, electromyographic, and pathologic features in polymyositis (PM) patients with hypothyroidism or hyperthyroidism, we conducted a MEDLINE and Chinese biomedicine database search to identify relevant literature published in the past 25 years. Seventeen cases were included. All patients were female (10 hypothyroidism patients, seven hyperthyroidism patients). The mean (SD) age of PM, hypothyroidism, and hyperthyroidism at diagnosis was 54.8 (16.7), 55.5 (16.5), and 32.7 years (10.2), respectively. PM diagnosis can precede or parallel hypothyroidism while PM may occur following the diagnosis of hyperthyroidism. The most common comorbidities were malignant tumors in these disorders, including thymoma, colon cancer, and thyroid cancer. Muscle weakness was described in 100% of patients. Other common manifestations included muscles’ atrophy and pain, deep tendon reflexes, polyarthralgia, and dysphagia. Most patients had markedly elevated creatine kinase and the presence of anti-Sjogren’s syndrome A (SSA) antibodies was also found in two cases. Malignancy associated with PM may more frequently occur in hypothyroidism than in hyperthyroidism. The abnormalities on electromyography and biopsy did not differ from those findings of PM. Therapy consisting of corticosteroids, thyroid hormone, or anti-thyroid drugs was administrated; however, poor prognosis seemed to be associated with malignant tumors as well as older age and the presence of anti-SSA antibodies. It is reasonable to suggest that those patients should be routinely evaluated for thyroid function, especially in older female and patients suffering from cancers.     

Differential toxicity of Mn2+ and Mn3+ to rat liver tissues: Oxidative damage,membrane fluidity and histopathological changes

Toxicity due to overexposure to manganese (Mn) is becoming increasingly prevalent. Mn-induced neurodegenerative toxicity has been demonstrated, but little is known concerning the adverse effects of the element on the liver. Under physiological conditions, manganese primarily exists as divalent manganese (Mn²⁺) and trivalent manganese (Mn³⁺). The present study was designed to evaluate and compare the effects of Mn²⁺ and Mn³⁺ on oxidative hepatic damage, membrane fluidity and histopathological changes in rats. Rats exposed to Mn²⁺ or Mn³⁺ (2.0 mg Mn/kg body weight) showed significant inhibition of superoxide dismutase (SOD) and glutathione peroxidase (GPx) activity, as well as decreased levels of glutathione (GSH) and increased levels of malondialdehyde (MDA) in liver tissues. We also showed a significant inhibition of SOD activity and increased MDA levels in hepatocyte nuclei. We also observed reduced Na⁺,K⁺-ATPase activity, increased MDA levels and decreased plasma membrane fluidity, which was accompanied by an increase of fluorescence anisotropy (r) values, in hepatic plasma membranes. In addition, Mn²⁺ and Mn³⁺ both caused histopathological changes, such as mononuclear cell infiltration, congestion, enlargement of the veins and sinusoids, hepatocellular damage, necrotic changes, mitochondrial hyperplasia, swelling and vacuolization, as determined by light and electron microscopy. Taken together, these data suggest that both Mn²⁺ and Mn³⁺ inhibit the normal physiological functioning of the liver. Under the experimental conditions used, the adverse effects of Mn²⁺ were more severe than those of Mn³⁺.     

CEST MRI of sepsis‐induced acute kidney injury

Sepsis‐induced acute kidney injury (SAKI) is a major complication of kidney disease associated with increased mortality and faster progression. Therefore, the development of imaging biomarkers to detect septic AKI is of great clinical interest. In this study, we aimed to characterize the endogenous chemical exchange saturation transfer (CEST) MRI contrast in the lipopolysaccharide (LPS)‐induced SAKI mouse model and to investigate the use of CEST MRI for detecting such injury. We used a SAKI mouse model that was generated by i.p. injection of 10 mg/kg LPS. The resulting kidney injury was confirmed by the elevation of serum creatinine and histology. MRI assessments were performed 24 h after LPS injection, including CEST MRI at different B₁ strengths (1, 1.8 and 3 μT), T₁ mapping, T₂ mapping and conventional magnetization transfer contrast (MTC) MRI. The CEST MRI results were analyzed using Z‐spectra, in which the normalized water signal saturation (S_sat/S₀) is measured as a function of saturation frequency. Substantial decreases in CEST contrast were observed at both 3.5 and ? 3.5 ppm frequency offset from water at all B₁ powers, with the most significant difference obtained at a B₁ of 1.8 μT. The average S_sat/S₀ differences between injured and normal kidneys were 0.07 (0.55 ± 0.04 versus 0.62 ± 0.04, P = 0.0028) and 0.07 (0.50 ± 0.04 versus 0.57 ± 0.03, P = 0.0008) for 3.5 and ? 3.5 ppm, respectively. In contrast, the T₁ and T₂ relaxation times and MTC contrast in the injured kidneys did not show a significant change compared with the normal control. Our results showed that CEST MRI is more sensitive to the pathological changes in injured kidneys than the changes in T₁, T₂ and MTC effect, indicating its potential clinical utility for molecular imaging of renal diseases.