Bound malondialdehyde in foods: bioavailability of N,N'-di-(4-methyl-1,4-dihydropyridine-3,5-dicarbaldehyde)lysine

Reactions between lipid peroxidation products and proteins in foods have detrimental nutritional effects, most importantly, losses of essential amino acids. One of the major products of the reaction of malondialdehyde and alkanals with amino groups are 4-substituted 1,4-dihydropyridine-3,5-dicarbaldehyde derivatives. The product of the reaction of lysine with malondialdehyde and acetaldehyde, N,N'-di-(4-methyl-1,4-dihydropyridine-3,5-dicarbaldehyde)lysine (MDDL), has been synthesized and used for in vitro and in vivo bioavailability studies. Release of free lysine did not occur in incubations of MDDL with tissue homogenates. After oral administration of radioactively labeled MDDL, radioactivity was only recovered in feces. Radioactivity was not incorporated into hepatic microsomes after intraperitoneal administration, which would have indicated release of available lysine. These results show that MDDL is a form of unavailable lysine, because it is not metabolized to free lysine and cannot be absorbed from the gut. Thus, formation of this derivative in foods would result in loss of available lysine.     

Middle ear cholesteatoma in 11 dogs

Middle ear cholesteatoma is a rare condition in dogs with chronic otitis. Otorrhea, otodinia, and pain on temporomandibular joint palpation are the most common clinical signs. Neurological abnormalities are often detectable. Computed tomography reveals the presence of an expansive and invasive unvascularized lesion involving the tympanic cavity and the bulla, with little or no contrast enhancement after administration of contrast mediu. Video-otoscopy may detect pearly growth or white/yellowish scales in the middle ear cavity. Surgery is the only therapy but is associated with a high risk of recurrence.     

Determination of triterpenic acids in human serum by high-performance liquid chromatography: triterpenoid interaction with serum protein

Terpenic acids are under development as therapeutic agents in numerous treatments. In support of pharmacokinetic and toxicological evaluations, a robust assay based on high-performance liquid chromatography (HPLC) was developed for the analysis of the terpenoids in human serum. For a clear understanding of the differences in biological activity of these compounds, the interactions between oleanolic or betulinic acids and human serum protein have been studied by ultraviolet-visible (UV-vis) absorption under physiological conditions. A combination of liquid/liquid extraction, centrifugation, and consecutive HPLC resulted in simultaneous separation, identification, and quantification of the oleanolic, betulinic, and ursolic acids. The validity of the developed method was established by determining linearity, recovery, precision, accuracy, limit of detection, and quantification. Detection limits were in the range of 3.3-4.3 ng/mL, and linearity values ranged up to 1 μg/mL. The repeatability of the method was good. All compounds can be well-distinguished by order of elution during liquid chromatography. The pentacyclic triterpenoids have been identified by retention time comparison to pure standards and quantified by an internal standard. The results by UV-vis absorption spectra experiments (240-340 nm) indicate that protein structures have been perturbed in the presence of oleanolic and betulinic acids.     

Screening for heat tolerance in common bean (Phaseolus vulgaris L.) lines and cultivars using JIP-test

The changes in chlorophyll a fluorescence, caused by high temperature (HT), have been used to study heat-tolerance in nine common bean (Phaseolus vulgaris L.) accessions (3 cultivars and 6 lines) available in the gene banks of Maritsa Vegetable Crops Research Institute and Institute for Plant Genetic Resources. The plants were grown in controlled greenhouse conditions until the blossoming stage, treated with HT (45° C) for 2 h and returned for recovery for 4 h at 23° C. The obtained results allowed us to differentiate four groups, among the studied bean plants, by their response to HT. The first group, includes a single cultivar – ‘Secuntsa’. The accession was considered heat sensitive, because it showed a decrease of its total performance index (PI_total), calculated by JIP-test, during HT stress and did not recover to the initial values. The second group, comprised of lines RH13, BBSR17, BBSR28, and ‘Starozagorski cher’, expressed an increase in PI_total during heat stress, which however was followed by a decline in PI_total values during recovery after HT treatment. The third group – RRR46 displayed a decrease in various JIP-test parameters during HT treatment followed by full recovery after returning the plants to 23° C. The accessions from the fourth group RH26D, ‘Ranit’, similarly to the control heat tolerant line 83201007 did not show significant alteration in PI_total. We assumed that the accessions from the fourth group are heat-tolerant. The line RRR46 is also promising in terms of heat tolerance because of its flexible response to HT treatment. These genotypes will be used in our further breeding program.     

Subcutaneously implanted tissue chambers: a pathophysiological study

Tissue and fluid changes occurring within tissue chambers were characterised as a function of time after subcutaneous implantation in cattle. Cytological and chemical investigation revealed that the composition of fluid within chambers approached the theoretical composition of true interstitial fluid as time after implantation progressed. Erythrocyte and leucocyte numbers decreased sharply immediately after implantation and had reached stable numbers by 40 days after implantation. At this stage, chamber fluid samples had lower total protein and albumin concentrations, higher K+ and Cl- concentrations and lower pH than corresponding blood samples. Despite an ongoing low-grade chronic inflammatory reaction resulting in fibrous encapsulation of chambers, the vascularity of chamber tissue did not diminish with time after implantation. By 40 days after implantation, the cellular and chemical constituents had stabilised enough to allow use of the model to study drug distribution.