The Effect of Zein, Leucine, and Glutamic Acid on the Urinary Excretion of Kynurenine, 3-Hydroxykynurenine, and 3-Hydroxyanthranilic Acid in the Rat

(From the Introduction): The quest for the cause of pellagra which started in the early eighteenth century is surrounded with many fascinating theories. According to Harris (1)*, the many early theories advanced for the causation of pellagra may be classified into four groups: toxins, infections, food deficiencies of quantity and quality, and vitamin deficiencies. Maize consumption was associated with pellagra as early as 1735 by Casal but its relationship to the disease was not exactly understood at that time. The first unreserved claim that pellagra results solely from the use of corn in the diet was made by Franzoni in 1807. Pellagra was defined as a food poisoning generally due to the use of spoiled corn, having the characteristics of endemicity in the countries where spoiled corn is consumed as food, and seasons in which the corn crop is most seriously damaged (2). Goldberger et al. (3) in 1916 made the observation that the diet of pellagrous patients was unbalanced, being low in protein. Later work in 1924 showed that zein, the major protein in corn, was low in tryptophan. When it was finally established that pellagra was caused by a deficiency of niacin and its precursor tryptophan, a possible explanation offered for the association between diets high in corn and pellagra was the low tryptophan content in zein. In 1945 Krehl et al. (4) made the observation that the addition of tryptophan-deficient proteins, such as gelatin and zein, to low-protein niacin-free diets resulted in the retardation of growth and the development of niacin-deficiency symptoms in rats. These symptoms were alleviated by the addition of tryptophan or niacin to the diets. The inhibition of growth which resulted from the inclusion of corn in the ration used by Krehl and his associates and the apparent dual role of niacin and tryptophan in counteracting this growth depression have resulted in considerable study on the mechanism of these relationships. In a study by Goldsmith et al. (5) human subjects fed corn diets developed clinical signs of a niacin deficiency within 50 days, whereas subjects fed a wheat diet containing the same amounts of niacin and tryptophan as the corn diet did not show any niacin deficiency symptoms until they had been on the diet for 80 days or more. These studies suggested that some component of corn interferes with the utilization of tryptophan and/or niacin. It was theorized that the development of niacin-deficiency symptoms resulting from ingestion of corn diets might be due to an amino acid imbalance. The ability of the rat to convert tryptophan to niacin has made it difficult to resolve the question of whether the substances causing such imbalances affect tryptophan utilization, or niacin utilization or the pathway in the conversion of niacin from tryptophan. In 1964 Coulter (6) studied the utilization of tryptophan for pyridine nucleotide synthesis in rats fed low-protein niacin-free diets containing either corn, zein, mixtures of the indispensable amino acids as found in zein with and without leucine, or a mixture of the dispensable amino acids as found in zein. The pyridine nucleotides are the metabolically-active form of niacin in the body. She found that zein, leucine, and one or more of the dispensable amino acids of zein interfered with the ability of the rat to synthesize pyridine nucleotides from tryptophan. In 1965 Ellis (7) studied the effect of the stepwise addition of the dispensable amino acids of zein on the utilization of L-tryptophan for pyridine nucleotide synthesis in rats fed low-protein niacin-free diets. Her findings indicated that glutamic acid and possibly tyrosine inhibited the utilization of tryptophan. The occurrence of certain intermediate products of tryptophan metabolism in the urine of mammals has provided important clues toward unraveling the metabolic pathway for the conversion of tryptophan to niacin. From the cumulative evidence obtained in studies with different organisms it appears that the initial steps in the major pathway of tryptophan metabolism are: tryptophan→ formylkynurenine → kynurenine → 3-hydroxykynurenine→ 3-hydroxyanthranilic acid (8). Recent studies have shown that 3-hydroxyanthranilic acid is further metabolized to niacin ribonucleotide (9). Many of the metabolites along the tryptophan-niacin pathway have been detected in urine of rats and humans. Estimation of the quantities of these metabolites in the urine under various experimental conditions has been helpful in assessing the metabolic use of tryptophan and in diagnosing certain diseases. In view of these considerations, this study was designed to determine the effect of zein, leucine, and glutamic acid on the urinary excretion of kynurenine, 3-hydroxykynurenine, and 3-hydroxyanthranilic acid in the rat. An interference in any of the steps in the pathway of tryptophan metabolism (indicated above) would be expected to cause an increase in the urinary excretion of the specific metabolite formed in the preceding step. For example, an interference in the conversion of 3-hydroxykynurenine to 3-hydroxyanthranilic acid would be expected to cause an increase in the urinary excretion of 3-hydroxykynurenine

Quantum cosmological perfect fluid model and its classical analogue

The quantization of gravity coupled to a perfect fluid model leads to a Schr\"odinger-like equation, where the matter variable plays the role of time. The wave function can be determined, in the flat case, for an arbitrary barotropic equation of state $p = \alpha\rho$; solutions can also be found for the radiative non-flat case. The wave packets are constructed, from which the expectation value for the scale factor is determined. The quantum scenarios reveal a bouncing Universe, free from singularity. We show that such quantum cosmological perfect fluid models admit a universal classical analogue, represented by the addition, to the ordinary classical model, of a repulsive stiff matter fluid. The meaning of the existence of this universal classical analogue is discussed. The quantum cosmological perfect fluid model is, for a flat spatial section, formally equivalent to a free particle in ordinary quantum mechanics, for any value of $\alpha$, while the radiative non-flat case is equivalent to the harmonic oscillator. The repulsive fluid needed to reproduce the quantum results is the same in both cases.Comment: Latex file, 13 page

Comments on "There is no axiomatic system for the quantum theory"

In a recent paper, Nagata [1] claims to derive inconsistencies from quantum mechanics. In this paper, we show that the inconsistencies do not come from quantum mechanics, but from extra assumptions about the reality of observables

Quantum gravity correction, evolution of scalar field and inflation

We take the first nontrivial coefficient of the Schwinger-DeWitt expansion as a leading correction to the action of the second-derivative metric-dilaton gravity. To fix the ambiguities related with an arbitrary choice of the gauge fixing condition and the parametrization for the quantum field, one has to use the classical equations of motion. As a result, the only corrections are the ones to the potential of the scalar field. It turns out that the parameters of the initial classical action may be chosen in such a way that the potential satisfies most of the conditions for successful inflation.Comment: 11 pages, 3 figure

Gla-rich protein is involved in the cross-talk between calcification and inflammation in osteoarthritis

Osteoarthritis (OA) is a whole-joint disease characterized by articular cartilage loss, tissue inflammation, abnormal bone formation and extracellular matrix (ECM) mineralization. Disease-modifying treatments are not yet available and a better understanding of osteoarthritis pathophysiology should lead to the discovery of more effective treatments. Gla-rich protein (GRP) has been proposed to act as a mineralization inhibitor and was recently shown to be associated with OA in vivo. Here, we further investigated the association of GRP with OA mineralization-inflammation processes. Using a synoviocyte and chondrocyte OA cell system, we showed that GRP expression was up-regulated following cell differentiation throughout ECM calcification, and that inflammatory stimulation with IL-1 beta results in an increased expression of COX2 and MMP13 and up-regulation of GRP. Importantly, while treatment of articular cells with gamma-carboxylated GRP inhibited ECM calcification, treatment with either GRP or GRP-coated basic calcium phosphate (BCP) crystals resulted in the down-regulation of inflammatory cytokines and mediators of inflammation, independently of its gamma-carboxylation status. Our results strengthen the calcification inhibitory function of GRP and strongly suggest GRP as a novel anti-inflammatory agent, with potential beneficial effects on the main processes responsible for osteoarthritis progression. In conclusion, GRP is a strong candidate target to develop new therapeutic approaches

Can biological quantum networks solve NP-hard problems?

There is a widespread view that the human brain is so complex that it cannot be efficiently simulated by universal Turing machines. During the last decades the question has therefore been raised whether we need to consider quantum effects to explain the imagined cognitive power of a conscious mind. This paper presents a personal view of several fields of philosophy and computational neurobiology in an attempt to suggest a realistic picture of how the brain might work as a basis for perception, consciousness and cognition. The purpose is to be able to identify and evaluate instances where quantum effects might play a significant role in cognitive processes. Not surprisingly, the conclusion is that quantum-enhanced cognition and intelligence are very unlikely to be found in biological brains. Quantum effects may certainly influence the functionality of various components and signalling pathways at the molecular level in the brain network, like ion ports, synapses, sensors, and enzymes. This might evidently influence the functionality of some nodes and perhaps even the overall intelligence of the brain network, but hardly give it any dramatically enhanced functionality. So, the conclusion is that biological quantum networks can only approximately solve small instances of NP-hard problems. On the other hand, artificial intelligence and machine learning implemented in complex dynamical systems based on genuine quantum networks can certainly be expected to show enhanced performance and quantum advantage compared with classical networks. Nevertheless, even quantum networks can only be expected to efficiently solve NP-hard problems approximately. In the end it is a question of precision - Nature is approximate.Comment: 38 page

Troubles with quantum anistropic cosmological models: Loss of unitarity

The anisotropic Bianchi I cosmological model coupled with perfect fluid is quantized in the minisuperspace. The perfect fluid is described by using the Schutz formalism which allows to attribute dynamical degrees of freedom to matter. A Schr\"odinger-type equation is obtained where the matter variables play the role of time. However, the signature of the kinetic term is hyperbolic. This Schr\"odinger-like equation is solved and a wave packet is constructed. The norm of the resulting wave function comes out to be time dependent, indicating the loss of unitarity in this model. The loss of unitarity is due to the fact that the effective Hamiltonian is hermitian but not self-adjoint. The expectation value and the bohmian trajectories are evaluated leading to different cosmological scenarios, what is a consequence of the absence of a unitary quantum structure. The consistency of this quantum model is discussed as well as the generality of the absence of unitarity in anisotropic quantum models.Comment: Latex file, 18 pages. To appear in General Relativity and Gravitatio

MELISSA: System Description and Spectral Features of Pre- and Post-Midnight F-Region Echoes

Most of the low‐latitude ionospheric radar observations in South America come from the Jicamarca Radio Observatory, located in the western longitude sector (∼75°W). The deployment of the 30 MHz FAPESP‐Clemson‐INPE (FCI) coherent backscatter radar in the magnetic equatorial site of São Luis, Brazil, in 2001 allowed observations to be made in the eastern sector (∼45°W). However, despite being operational for several years (2001–2012), FCI only made observations during daytime and pre‐midnight hours, with a few exceptions. Here, we describe an upgraded system that replaced the FCI radar and present results of full‐night F‐region observations. This radar is referred to as Measurements of Equatorial and Low‐latitude Ionospheric irregularities over São Luís, South America (MELISSA), and made observations between March 2014 and December 2018. We present results of our analyses of pre‐ and post‐midnight F‐region echoes with focus on the spectral features of post‐midnight echoes and how they compare to spectra of echoes observed in the post‐sunset sector. The radar observations indicate that post‐midnight F‐region irregularities were generated locally and were not a result of “fossil” structures generated much earlier in time (in other longitude sectors) and that drifted into the radar field‐of‐view. This also includes cases where the echoes are weak and that would be associated with decaying equatorial spread F (ESF) structures. Collocated digisonde observations show modest but noticeable F‐region apparent uplifts prior to post‐midnight ESF events. We associate the equatorial uplifts with disturbed dynamo effects and with destabilizing F‐region conditions leading to ESF development

Gla Rich Protein (GRP) is associated to osteoarthritis being highly accumulated in the joint tissues and synovial fluid

info:eu-repo/semantics/publishedVersio