Effect of lidocaine and pyromecaine on the size of an experimental myocardial infarct

The experiments on rats with a 3-day myocardial infarction caused by the left coronary artery ligation have shown that multiple lidocaine and pyromecaine injections according to a given scheme decrease the size of the necrosis area. Drug effects were not related to their action on the blood supply of the ischemic area.     

Reasons for disorders of fatty acid oxidation in isolated heart mitochondria during ischemia

The influence of malate and cytochrome c on fatty acid oxidation under control and ischemic conditions was investigated. In the medium without malate, cytochrome did not make fatty acid oxidation decreased during ischemia return to normal. Oxidation in the media containing malate and cytochrome did not differ from control only when it was measured after preliminary oxidation of endogenous substrates. The ratio of palmitoyl-CoA and palmitoyl carnitine to the respiration rates at state 3 was unchanged at 60 min ischemia. Apparently, no changes in carnitine acyltransferase playing a role in oxidation of palmitoyl-CoA took place. Thus, the decrease of fatty acid oxidation at early periods of ischemia is largely caused by a reduction in the content of cytochrome c and intermediates of Krebs cycle in the mitochondria.     

Habitat preference in the critically endangered yellow‐tailed woolly monkey (Lagothrix flavicauda) at La Esperanza,Peru

Habitat loss is one of the main threats to wildlife. Therefore, knowledge of habitat use and preference is essential for the design of conservation strategies and identification of priority sites for the protection of endangered species. The yellow‐tailed woolly monkey (Lagothrix flavicauda Humboldt, 1812), categorized as Critically Endangered on the IUCN Red List, is endemic to montane forests in northern Peru where its habitat is greatly threatened. We assessed how habitat use and preference in L. flavicauda are linked to forest structure and composition. The study took place near La Esperanza, in the Amazonas region, Peru. Our objective was to identify characteristics of habitat most utilized by L. flavicauda to provide information that will be useful for the selection of priority sites for conservation measures. Using presence records collected from May 2013 to February 2014 for one group of L. flavicauda, we classified the study site into three different use zones: low‐use, medium‐use, and high‐use. We assessed forest structure and composition for all use zones using 0.1 ha Gentry vegetation transects. Results show high levels of variation in plant species composition across the three use zones. Plants used as food resources had considerably greater density, dominance, and ecological importance in high‐use zones. High‐use zones presented similar structure to medium‐ and low‐use zones; thus it remains difficult to assess the influence of forest structure on habitat preference. We recommend focusing conservation efforts on areas with a similar floristic composition to the high‐use zones recorded in this study and suggest utilizing key alimentation species for reforestation efforts.     

Purification and various properties of asialoglycoprotein receptors from the mouse liver

The receptor for asialoglycoproteins was isolated from murine liver and was purified by means of biospecific chromatography on sepharose-Asialo-orosomucoid. The obtained receptor with an absorption maximum at 277 nm binds to the nonreducing terminal galactosyl residues of glycoproteins similar to the receptors from liver of other mammalians. The interaction between this receptor and desialylated glycoproteins requires the presence of calcium. The dependence of specific binding on the concentration of [125I]acialo-orosomucoid used as a ligand gives a saturating curve. The dissociation constant for the receptor-ligand complex is 0.4 X 10(-9) M. Similar to asialo-orosomucoid, the receptor binds the p-aminophenyl-beta-D-galactopyranoside derivatives of bovine serum albumin, ovalbumin and acid alpha-glucosidase synthesized by us earlier. Possible use of the asialoglycoprotein receptor as a highly specific carrier transporting the modified acid alpha-glucosidase to hepatocyte lysosomes is discussed.     

The role of pH* and buffer capacity in the recovery of function of smooth muscle cooled to −13 °C in unfrozen media

It has often been suggested that pH changes may be implicated in the injury sustained by biological systems during cooling. This particular mechanism of cryoinjury, however, has received little attention undoubtedly because of the difficulties encountered in making accurate pH measurements at low temperatures.New pH* scales established for some mixtures of dimethyl sulfoxide and water at low temperatures are used in this study to assess the effect of pH* and buffering ability upon the integrity of mammalian smooth muscle stored at −13 °C in a variety of unfrozen solutions containing 30% (w/v) Me₂SO. Smooth muscle, as a component of every organ, is a good model tissue intermediate between cells and organs. Furthermore, its overall function is conveniently tested by measuring isometric contractile responses to the drug histamine. In this way the function of strips of guinea pig taenia coli were examined at 37 °C before and after storage at −13 °C in potassiumrich media containing a variety of zwitterionic buffers. Functional recovery depends markedly on the pH* with a welldefined optimum at the surprisingly high pH*₋₁₃ of 9.2. In medium containing TES buffer, which has a maximum buffer capacity at pH*₋₁₃= 8.6, the cooled muscles recover 50% of their control contractility but in medium containing the buffer Tricine, which has a maximum capacity at the optimum pH* for recovery, the contractile response upon rewarming improves to 70%.These data are the first to quantify the effect of pH in cryopreservation on a sound theoretical basis and some of the possible underlying mechanisms are discussed.     

Relationship between postabsorptive respiratory exchange ratio and plasma free fatty acid concentrations

The relationship between overnight postabsorptive (fasting) respiratory exchange ratio (RER) and plasma FFA concentrations was addressed using data from three separate protocols, each of which involved careful control of the antecedent diet. Protocol 1 examined the relationship between fasting RER and the previous daytime RER. In Protocol 2 fasting, RER and plasma palmitate concentrations were measured in 29 women and 31 men (body mass index <30 kg·m⁻²). Protocol 3 analyzed data from Nielsen et al. (Nielsen, S., Z. K. Guo, J. B. Albu, S. Klein, P. C. O''Brien, M. D. Jensen. 2003. Energy expenditure, sex and endogenous fuel availability in humans. J. Clin. Invest. 111: 981-988.) to understand how fasting RER and palmitate concentrations relate within individuals during four consecutive measurements. The results were as follows: 1) Fasting RER was correlated (r = 0.74, P < 0.001) with the previous day''s average RER, and less so with RER variability. 2) Fasting RER was correlated (r = −0.39, P = 0.007) with fasting plasma palmitate concentrations. 3) The pattern of the RER/palmitate relationship was similar within individuals and between individuals; a negative slope was observed significantly more often than a positive slope (χ² test; P < 0.001). Our findings suggest that, despite a fixed food quotient, the slight departures from energy equilibrium in a controlled General Clinical Research Center environment can effect plasma FFA concentrations. We suggest that including indirect calorimetry as part of FFA metabolism studies may aid in data interpretation.     

Quantifying Biomass Changes of Single CD8+ T Cells during Antigen Specific Cytotoxicity

Existing approaches that quantify cytotoxic T cell responses rely on bulk or surrogate measurements which impede the direct identification of single activated T cells of interest. Single cell microscopy or flow cytometry methodologies typically rely on fluorescent labeling, which limits applicability to primary cells such as human derived T lymphocytes. Here, we introduce a quantitative method to track single T lymphocyte mediated cytotoxic events within a mixed population of cells using live cell interferometry (LCI), a label-free microscopy technique that maintains cell viability. LCI quantifies the mass distribution within individual cells by measuring the phase shift caused by the interaction of light with intracellular biomass. Using LCI, we imaged cytotoxic T cells killing cognate target cells. In addition to a characteristic target cell mass decrease of 20–60% over 1–4 h following attack by a T cell, there was a significant 4-fold increase in T cell mass accumulation rate at the start of the cytotoxic event and a 2–3 fold increase in T cell mass relative to the mass of unresponsive T cells. Direct, label-free measurement of CD8+ T and target cell mass changes provides a kinetic, quantitative assessment of T cell activation and a relatively rapid approach to identify specific, activated patient-derived T cells for applications in cancer immunotherapy.