Krzysztof Piotr Michalak

Key Roles of Glutamine Pathways in Reprogramming the Cancer Metabolism

Glutamine (GLN) is commonly known as an important metabolite used for the growth of cancer cells but the effects of its intake in cancer patients are still not clear. However, GLN is the main substrate for DNA and fatty acid synthesis. On the other hand, it reduces the oxidative stress by glutathione synthesis stimulation, stops the process of cancer cachexia, and nourishes the immunological system and the intestine epithelium, as well. The current paper deals with possible positive effects of GLN supplementation and conditions that should be fulfilled to obtain these effects. The analysis of GLN metabolism suggests that the separation of GLN and carbohydrates in the diet can minimize simultaneous supply of ATP (from glucose) and NADPH2 (from glutamine) to cancer cells. It should support to a larger extent the organism to fight against the cancer rather than the cancer cells. GLN cannot be considered the effective source of ATP for cancers with the impaired oxidative phosphorylation and pyruvate dehydrogenase inhibition. GLN intake restores decreased levels of glutathione in the case of chemotherapy and radiotherapy; thus, it facilitates regeneration processes of the intestine epithelium and immunological system.

Impaired body balance control in adults with strabismus

Previous studies revealed that people with binocular vision disorders have poor postural stability. However, most of the research was performed only on children and under binocular viewing condition, that could negatively affect the results. The aim of the current study was to investigate the influence of extra-ocular proprioceptive signals on postural stability in young adults with binocular vision disorders. Moreover, additional mental task was introduced to detect any postural compensation which could possibly hide the real influence of afferent extra-ocular signals. 21 Subjects, aged 18-45 yrs, with horizontal strabismus, were qualified to binocular vision disorders (BVD) group. 41 subjects, aged 19-45 yrs, with no strabismus formed the normal binocular vision (NBV) group. Posturography data were collected in 2 separate parts: (1) quiet standing (Single-Task), and (2) performance of a mental task while standing (Dual-Task). Each part consisted of three 60-s viewing conditions, with: (1) dominant/fellow eye (DE), (2) non-dominant/strabismic eye (NDE), and with (3) both eyes closed (EC). Subjects were looking at X located at the distance of 150 cm. Generally, BVD group showed elevated body balance during quiet stance compared to NBV group. Interestingly, better stabilization in BVD group occurred under NDE viewing. Surprisingly, additional mental task improved the postural stability in BVD group almost to the level of NBV group. These findings emphasize the role of the eye-muscle signals in postural control and suggest that suitable vision therapy can be the appropriate way to improve body balance/motor functions in people with binocular vision disorders.

How to estimate the correlation dimension of high-dimensional signals?

The paper presents improvements to the Takens-Ellner (TE) algorithm estimating the correlation dimension (d) of high-dimensional signals. The signal being the sum of 4 Lorenz signals and possessing the correlation dimension d approximately equal to 8 was analyzed. The conversion of TE to the classic Grassberger-Proccacia (GP) algorithm is presented that shows the advantage of TE over the GP algorithm. The maximal d estimated for the given number of points in phase space is significantly higher for the TE algorithm than for the GP algorithm. The formula for the precision of individual d estimation is presented. The paper shows, how to estimate the distance corresponding to the end of the Linear Scaling Region in the correlation integral function, even before starting the procedure of d estimation. It makes it possible to reject the majority of longer distances from the analysis reducing the computation time considerably.

Treatment of the Fluoroquinolone-Associated Disability: The Pathobiochemical Implications

Long-term fluoroquinolone-associated disability (FQAD) after fluoroquinolone (FQ) antibiotic therapy appears in recent years as a significant medical and social problem, because patients suffer for many years after prescribed antimicrobial FQ treatment from tiredness, concentration problems, neuropathies, tendinopathies, and other symptoms. The knowledge about the molecular activity of FQs in the cells remains unclear in many details. The effective treatment of this chronic state remains difficult and not effective. The current paper reviews the pathobiochemical properties of FQs, hints the directions for further research, and reviews the research concerning the proposed treatment of patients. Based on the analysis of literature, the main directions of possible effective treatment of FQAD are proposed: (a) reduction of the oxidative stress, (b) restoring reduced mitochondrion potential ΔΨm, (c) supplementation of uni- and bivalent cations that are chelated by FQs and probably ineffectively transported to the cell (caution must be paid to Fe and Cu because they may generate Fenton reaction), (d) stimulating the mitochondrial proliferation, (e) removing FQs permanently accumulated in the cells (if this phenomenon takes place), and (f) regulating the disturbed gene expression and enzyme activity.

The Filtering of the Posturographic Signals Shows the Age Related Features

Objective. Lower frequencies of slow oscillations of the posturographic signals can be removed using high-pass filtering. This procedure releases postural reflexes possessing higher frequencies and lower amplitude range. Mutual dependence between the x and y components of posturographic signals was analyzed using principal component analysis (PCA). The posturographic signals of old patients with idiopathic gait disturbance were compared with the control group of similar age and with younger patients. There was also the analysis of the influence of the eyes state (open versus closed) and the head position (normal or bent back). The statistically significant differences in the mutual dependence between x and y components between the groups of patients were analyzed using MANOVA. The significant differences were observed mainly in the range of filter frequencies f = 0.1–1.5 Hz and f = 2.2–5.5 Hz with a maximum effect at approximately 4-5 Hz. A detailed post-hoc analysis is also presented. The differences in the higher frequency range suggest the main disturbance to be connected with the spinal reflexes. Visual and vestibular support appear insufficient for postural stability control in the idiopathic gait disturbance group. The results suggest that idiopathic gait disturbance is the final stage of the aging process of postural system.

Estimating correlation dimension of high-dimensional signals - quick algorithm

The paper describes the improvements and corrections to the method of estimation of correlation dimension of d for high-dimensional signals (HDS). The following problems are described: (a) presentation of the quick version of the algorithm that reduces computation time, (b) improvement of the precision of the elementary Takens-Ellner formula estimating d, (c) the problem of strongly non-gaussian signals and its possible normalisation. Appendix discusses the use of author’s Matlab function estimating d which is available for public use.