Effect of vitamin A deficiency on the incorporation of C-14-leucine into tissue proteins of rats

Early response assessment after CyberKnife stereotactic radiosurgery for symptomatic vertebral hemangioma by quantitative parameters from dynamic contrast-enhanced MRI

PURPOSE

The present study aimed to explore the value of DCE-MRI to evaluate the early efficacy of CyberKnife stereotactic radiosurgery in patients with symptomatic vertebral hemangioma (SVH).

METHODS

A retrospective analysis of patients with spinal SVH who underwent CyberKnife stereotactic radiosurgery from January 2017 to August 2019 was performed. All patients underwent DCE-MRI before treatment and three months after treatment. The parameters included volume transfer constant (K^trans), transfer rate constant (K_ep), and extravascular extracellular space volume fraction (V_e).

RESULTS

A total of 11 patients (11 lesions) were included. After treatment, six patients (54.5%) had a partial response, five patients (45.4%) had stable disease, and three patients (27.3%) presented with reossification. K^trans and K_ep decreased significantly in the third month after treatment (p = 0.003 and p = 0.026, respectively). ΔK^trans was -46.23% (range, -87.37 to -23.78%), and ΔK_ep was -36.18% (range, -85.62 to 94.40%). The change in V_e was not statistically significant (p = 0.213), and ΔV_e was -28.01% (range, -58.24 to 54.76%).

CONCLUSION

DCE-MRI parameters K^trans and K_ep change significantly after CyberKnife stereotactic radiosurgery for SVH. Thus, DCE-MRI may be of value in determining the early efficacy of CyberKnife stereotactic radiosurgery.

The Roles of Vitamin A in the Regulation of Carbohydrate, Lipid, and Protein Metabolism

Currently, two-thirds of American adults are overweight or obese. This high prevalence of overweight/obesity negatively affects the health of the population, as obese individuals tend to develop several chronic diseases, such as type 2 diabetes and cardiovascular diseases. Due to obesity's impact on health, medical costs, and longevity, the rise in the number of obese people has become a public health concern. Both genetic and environmental/dietary factors play a role in the development of metabolic diseases. Intuitively, it seems to be obvious to link over-nutrition to the development of obesity and other metabolic diseases. However, the underlying mechanisms are still unclear. Dietary nutrients not only provide energy derived from macronutrients, but also factors such as micronutrients with regulatory roles. How micronutrients, such as vitamin A (VA; retinol), regulate macronutrient homeostasis is still an ongoing research topic. As an essential micronutrient, VA plays a key role in the general health of an individual. This review summarizes recent research progress regarding VA's role in carbohydrate, lipid, and protein metabolism. Due to the large amount of information regarding VA functions, this review focusses on metabolism in metabolic active organs and tissues. Additionally, some perspectives for future studies will be provided.

Native fluorescence from juvenile stages of common food storage insects

Insect infestation of stored foods has significant economic and health consequences; the development of novel methods of detection thus presents considerable opportunities. The fluorescence from nine species of storage insects (beetles and moths) was studied; the juvenile stages of all nine species exhibited fluorescence under long-wave (365 nm) UV light; none of the adult insects emit fluorescence, so the fluorophore(s) might be a compound(s) associated with the unsclerotized cuticle. The spectra of larval stages of Ephestia kuehniella, Oryzaephilus surinamensis, Corcyra cepahlonica, Tribolium castaneum, and Tribolium confusum exhibited excitation maxima in the range from 345 to 350 nm and emission maxima in the range from 421 to 427 nm, suggesting that fluorescence arises from a common chromophore; similarities in fluorescence properties implicate one of the many pteridine ring-containing compounds (pterins) commonly found in insects. Larvae and even eggs were readily imaged on foods using fluorescence under 365-nm excitation. Fluorescence thus appears to be ubiquitous in immature food storage insects, and fluorescence detection may be useful as a general method to detect insects in foods and agricultural commodities during storage or processing.

Studies on the mode of action of diphtheria toxin. V. Protein metabolism in a guinea pig model simulating chronic diphtheritic toxemia

An experimental model of "chronic" diphtheria intoxication in the guinea pig was developed. Adult guinea pigs, subjected to a regimen of multiple sublethal doses of purified diphtheria toxin (total of 1.4 minimum lethal doses divided equally in four daily doses), developed a toxemia which terminated in death between 6 and 8 days. During an advanced stage of illness, de novo protein synthesis was assessed by in vivo incorporation of tritiated leucine into tissue proteins. With the exception of pancreas and skeletal muscle, protein synthesis in healthy, control and toxin-treated guinea pigs was comparable. The absence of notable impairment of protein synthesis in this experimental situation is discussed in terms of the mode of action of the diphtheria toxin and the pathophysiology of the disease.