Heat balance of the human body: influence of variations of locally distributed parameters

Human body temperature control is characterized by a local dependence of system variables and parameters. Essential properties regarding inhomogeneity of the passive system have been investigated using mathematical methods. The general diffusion-equation has been solved using implicit finite difference methods with nonlinear boundary conditions. In order to allow comparison with experimental results, a simple ideal controller has been defined. On the basis of an inhomogeneous cylinder model with four concentric layers, influences of variations due to differences between tissues and individuals or measurements of parameters such as basal metabolism and conductivity have been studied. Stationary temperature profiles calculated for homogeneous and inhomogeneous conditions have been compared. Finally, the influence of blood flow has been discussed, as well as the stationary behaviour of profiles due to blood flow and blood flow control. The change of sign of curvature of temperature profile is possible only if blood flow mechanisms and the local distribution of metabolism are taken into account.     

Effect of fasting, branched-chain amino acids, and glucocorticoids on histone H1 extractability from rat skeletal muscle.

The effect of 72 h fasting, nutritional therapy of fasted rats, and acute and chronic glucocorticoid treatment on the yield of histone H1 from rat hind limb muscles was determined. Fasting significantly enhanced the extractability of muscle H1. The effect of treating starved rats with glucose alone, or with glucose supplemented with branched-chain amino acids (BCAA), or with two commercial preparations of mixtures of essential and non-essential amino acids was evaluated. Treatment of starved rats with glucose alone significantly decreased H1 extractability from muscles, but isocaloric treatment with glucose supplemented with BCAA or two commercial preparations of amino acid mixtures was more effective. Glucocorticoid treatment for 5 days enhanced the yield of H1 from muscles less than starvation. The enhanced H1 extractability from muscles noted in starved rats is similar to that reported in rats with insulinopenic diabetes and may reflect changes in nuclear fragility.     

Interaction between the extracellular matrix and lymphatics: Consequences for lymphangiogenesis and lymphatic function

The lymphatic system is important for body fluid balance as well as immunological surveillance. Due to the identification of new molecular markers during the last decade, there has been a recent dramatic increase in our knowledge on the molecular mechanisms involved in lymphatic vessel growth (lymphangiogenesis) and lymphatic function. Here we review data showing that although it is often overlooked, the extracellular matrix plays an important role in the generation of new lymphatic vessels as a response to physiological and pathological stimuli. Extracellular matrix-lymphatic interactions as well as biophysical characteristics of the stroma have consequences for tumor formation, growth and metastasis. During the recent years, anti-lymphangiogenesis has emerged as an additional therapeutic modality to the clinically applied anti-angiogenesis strategy. Oppositely, enhancement of lymphangiogenesis in situations of lymph accumulation is seen as a promising strategy to a set of conditions where few therapeutic avenues are available. Knowledge on the interaction between the extracellular matrix and the lymphatics may enhance our understanding of the underlying mechanisms and may ultimately lead to better therapies for conditions where reduced or increased lymphatic function is the therapeutic target.     

Transpeptidation in sequence analysis. Investigations concerning a native and a synthetic hexapeptide.

On sequencing a hemoglobin a peptic hexapeptide with the amino acid composition Asp2, Gly, Val, Lys2 was isolated. Cleavage of this peptide with Tos-Phe-CH2Cl-trypsin resulted in the fragments Asp-Lys, Gly-Asp, Val-Lys, Asp--Lys-Gly-Asp, Asp-Lys-Val-Lys and Val-Lys-Gly--Asp. From these data two possible but inconsistent sequences for the hexapeptide can be derived: Asp-Lys-Val-Lys-Gly-Asp and Val-Lys-Asp-Lys-Gly-Asp. Fragments obtained by other cleavage procedures, direct sequencing of the globin peptide-chain with a sequenator as well as X-ray data of this hemoglobin show, that only the sequence starting with Asp occurs in the intact protein. Therefore the peptide Asp-Lys-Gly-Asp must have been formed by transpeptidation during sequence work. In order to verify this, Asp-Lys-Val-Lys-Gly-Asp was synthesized by an unequivocal, conventional procedure. Tryptic digestion of this hexapeptide also resulted in ASP-Lys-Gly-Asp in addition to the expected fragments. Thus it has been shown for the first time, that sequencing conditions may alter the constitution of a peptide.     

Arachidonic acid metabolites and colchicine in Behçet's disease (BD)

Vasculitis is accepted to be the basis of Behçet's disease (BD) which is a multisystem disease, and the arachidonic acid(AA) metabolites acting as balancing mediators in the organism are accepted to be responsible for the vasculitis.In this study, we examined the prostaglandin E₂ (PGE₂) and leukotriene C₄ (LTC₄) levels of the patients with BD before and after colchicine therapy. We found a statistical decrease in the PGE₂ and LTC₄ levels after colchicine therapy compared to the previous levels, concluding that colchicine inhibits the inflammation and the polymorphonuclear leukocyte (PML) chemotaxis by inhibiting the cyclooxygenase and lipoxygenase patways.     

The rejuvenating influence of young plasma on aged intestine

This study aims to investigate the effects of plasma exchange on the biomolecular profiles and histology of ileum and colon tissues in young and aged Sprague–Dawley male rats. Fourier transform infrared (FTIR) spectroscopy, linear discriminant analysis and support vector machine (SVM) techniques were employed to analyse the lipid, protein, and nucleic acid indices in young and aged rats. Following the application of young plasma, aged rats demonstrated biomolecular profiles similar to those of their younger counterparts. Histopathological and immunohistochemical assessments showed that young plasma had a protective effect on the intestinal tissues of aged rats, increasing cell density and reducing inflammation. Additionally, the expression levels of key inflammatory mediators tumour necrosis factor-alpha and cyclooxygenase-2 significantly decreased after young plasma administration. These findings underscore the therapeutic potential of young plasma for mitigating age-related changes and inflammation in the intestinal tract. They highlight the critical role of plasma composition in the ageing process and suggest the need for further research to explore how different regions of the intestines respond to plasma exchange. Such understanding could facilitate the development of innovative therapies targeting the gastrointestinal system, enhancing overall health during ageing.