Silymarin and silybin are widely used for their hepatoprotective properties. Our previous studies confirm positive effect of silymarin on lipoprotein profile and lipid homeostasis. Advanced drug forms may improve the bioavailability of these compounds. In this study, we investigate the effects of silybin in different drug forms (standardized silybin, micronized silybin, and silybin in form of phytosomes) on dyslipidemia and glucose metabolism in hereditary hypertriglyceridemic (HHTg) rats. Male HHTg rats were divided into four groups of seven animals and were fed by experimental diets. Silybin significantly decreased serum level of triglycerides in groups of rats fed by standardized silybin and silybin in form of phytosomes compared to control group. Results show that silybin did not affect the total cholesterol level, but significantly increased the levels of HDL cholesterol in all groups of animals. Silybin in a standardized form had the highest hypotriglyceridemic effect. On the other hand, the micronized form has caused the highest increase of protective HDL and most significantly decreased glucose and insulin levels. Our results suggest that silybin is probably responsible for some positive properties of silymarin. Subsequent dose-dependent studies of silybin action may reveal the intensity of its positive effects on lipid and glucose parameters., M. Poruba, Z. Matušková, L. Kazdová, O. Oliyarnyk, H. Malínská, I. Tozzi di Angelo, R. Večeřa., and Obsahuje bibliografii
Biological systems are able to switch their neural systems into inhibitory states and it is therefore important to build mathematical models that can explain such phenomena. If we interpret such inhibitory modes as `positive' or `negative' steady states of neural networks, then we will need to find the corresponding fixed points. This paper shows positive fixed point theorems for a particular class of cellular neural networks whose neuron units are placed at the vertices of a regular polygon. The derivation is based on elementary analysis. However, it is hoped that our easy fixed point theorems have potential applications in exploring stationary states of similar biological network models.
In this paper, we employ some new techniques to study the existence of positive periodic solution of $n$-species neutral delay system
\[ N^{\prime }_i(t)=N_i(t)\biggl [a_i(t)-\sum _{j=1}^n\beta _{ij}(t)N_j(t)- \sum _{j=1}^nb_{ij}(t)N_j(t-\tau _{ij}(t))-\sum _{j=1}^nc_{ij}(t) N^{\prime }_j(t-\tau _{ij}(t))\biggr ]. \] As a corollary, we answer an open problem proposed by Y. Kuang.
This paper deals with the existence of positive ω-periodic solutions for the neutral functional differential equation with multiple delays (u(t) − cu(t − δ))′ + a(t)u(t) = f(t, u(t − τ1), . . . , u(t − τn)). The essential inequality conditions on the existence of positive periodic solutions are obtained. These inequality conditions concern with the relations of c and the coefficient function a(t), and the nonlinearity f(t, x1, . . . , xn). Our discussion is based on the perturbation method of positive operator and fixed point index theory in cones.
Introduction: Routine surveillance of colorectal cancer includes serial measurements of CEA levels. Although not routinely indicated Ca 19-9 is also a tool for recurrence. When any of these serum markers is elevated during follow up, this could represent a recurrence. The management of elevated tumor marker levels include clinical exams, endoscopy and conventional imaging–ultrasound, CT, MRI. Objective: To evaluate the positive predictive value of CEA and Ca19-9 as tumor markers for recurrent colorectal cancer in cases where conventional imaging and endoscopic studies fail to localize disease. Materials and methods: A total of 75 patients with elevated CEA and/or Ca19-9 serum levels and negative endoscopic exam as well as negative abdominal CT and Chest X-ray were included in the study. CEA levels were tested in 50 patients. Ca 19-9 was tested in 65 patients. 34 of the patients had both markers tested. All patients underwent whole body 18F-FDG PET/CT. Patients with negative of equivocal PET scan were further followed up (10 to 24 months). Results: Based on the reference standard – the results from PET/CT, if positive and the results from follow-up in cases of negative or equivocal scans, the positive predictive value of Ca 19-9 was 84% and that of CEA -83%. There was no significant difference in the PPV of Ca19-9 and CEA. Conclusion: Elevated CEA and Ca 19-9 levels in patients under active surveillance after operation for colorectal cancer have high positive predictive value for recurrence, even in cases where conventional work-up – endoscopy and CT don’t localize disease., Yana Bocheva, Pavel Bochev, and Literatura
The positive solution is studied for a (k, n - k) conjugate boundary value problem. The nonlinear term is allowed to be singular with respect to both the time and space variables. By applying the approximation theorem for completely continuous operators and the Guo-Krasnosel’skii fixed point theorem of cone expansion-compression type, an existence theorem for a positive solution is established.
Consider a class of elliptic equation of the form −∆u − λ ⁄ |x| 2 u = u 2 ∗−1 + µu −q in Ω \ {0} with homogeneous Dirichlet boundary conditions, where 0 ∈ Ω ⊂ RN (N ≥ 3), 0 < q < 1, 0 < λ < (N − 2)2 /4 and 2∗ = 2N/(N − 2). We use variational methods to prove that for suitable µ, the problem has at least two positive weak solutions.
We study a third order singular boundary value problem with multi-point boundary conditions. Sufficient conditions are obtained for the existence of positive solutions of the problem. Recent results in the literature are significantly extended and improved. Our analysis is mainly based on a nonlinear alternative of Leray-Schauder.
In the paper the differential inequality ∆pu + B(x, u) ≤ 0, where ∆pu = div(||∇u|| p−2∇u), p > 1, B(x, u) ∈ C(Rn × R, R) is studied. Sufficient conditions on the function B(x, u) are established, which guarantee nonexistence of an eventually positive solution. The generalized Riccati transformation is the main tool.
We study the existence of positive solutions for the p-Laplace Emden-Fowler equation. Let H and G be closed subgroups of the orthogonal group O(N) such that H G ⊂ O(N). We denote the orbit of G through x ∈ R N by G(x), i.e., G(x) := {gx: g ∈ G}. We prove that if H(x) G(x) for all x ∈ Ω and the first eigenvalue of the p-Laplacian is large enough, then no H invariant least energy solution is G invariant. Here an H invariant least energy solution means a solution which achieves the minimum of the Rayleigh quotient among all H invariant functions. Therefore there exists an H invariant G non-invariant positive solution.