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The HERV-W family of human endogenous retroviruses represents a group of numerous sequences that show close similarity in genetic composition. It has been documented that some members of HERV-W-derived expression products are supposed to play significant role in humans' pathology, such as multiple sclerosis or schizophrenia. Other members of the family are necessary to orchestrate physiological processes (eg, ERVWE1 coding syncytin-1 that is engaged in syncytiotrophoblast formation). Therefore, an assay that would allow the recognition of particular form of HERV-W members is highly desirable. A peptide nucleic acid (PNA)-mediated technique for the discrimination between multiple sclerosis-associated retrovirus and ERVWE1 sequence has been developed. The assay uses a PNA probe that, being fully complementary to the ERVWE1 but not to multiple sclerosis-associated retrovirus (MSRV) template, shows high selective potential. Single-stranded DNA binding protein facilitates the PNA-mediated, sequence-specific formation of strand invasion complex and, consequently, local DNA unwinding. The target DNA may be then excluded from further analysis in any downstream process such as single-stranded DNA-specific exonuclease action. Finally, the reaction conditions have been optimized, and several PNA probes that are targeted toward distinct loci along whole HERV-W env sequences have been evaluated. We believe that PNA/single-stranded DNA binding protein-based application has the potential to selectively discriminate particular HERV-W molecules as they are at least suspected to play pathogenic role in a broad range of medical conditions, from psycho-neurologic disorders (multiple sclerosis and schizophrenia) and cancers (breast cancer) to that of an auto-immunologic background (psoriasis and lupus erythematosus). [ABSTRACT FROM AUTHOR]

The sequence-dependent, acid- or base-catalysed aspartimide formation is one of the most serious side reactions in solid-phase synthesis of peptides containing aspartic acid. In the present work, we investigated the susceptibility of 4-{ N-[1-(4,4-dimethyl-2,6-dioxocyclohexylidene)-3-methylbutyl]amino}benzyl (Dmab), an aspartic acid β-carboxy side-chain protecting group, for aspartimide formation. As a model, 15-amino acid-residue galanin fragment analogue containing the Asp-Ala motif was used during Fmoc-based solid-phase synthesis. Our study showed a strong tendency of Dmab-protected peptide to form aspartimide with unusual high efficiency. Furthermore, to investigate the susceptibility of Asp-Ala motif for aspartimide formation during the synthesis using Asp(ODmab), a 5-amino acid-residue galanin fragment LGPDA, different types of resin linkers, variety of Fmoc-deprotection conditions and coupling methods were applied. Copyright © 2007 European Peptide Society and John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Aspartimide (Asi) formation is one of the most serious side reactions that can occur both during solid phase synthesis and storage of peptides containing aspartic acid. Although numerous studies on the mechanism of Asi formation conducted so far, the problem still remains unresolved and relatively little is known about the impact of this side reaction on biological properties of such modified peptides. In the present work we characterized the effect of Asi formation on biological properties of galanin(1-15) analogue modified in position 14 with aspartic acid, investigating its action on rat isolated gastric smooth muscles and glucose-induced insulin secretion from rat isolated islets of Langerhans. Our results show that this side process may adversely affect biological properties of such modified peptides. As we expected, modification of GAL(1-15)NH(2) structure changed the interaction of GAL(1-15)NH(2) with its receptors and consequently yielded peptide which, in studies on insulin secretion, showed insulinotropic- and antagonistic activities as compared to Asi-free analogue.

Unlabelled: The bronchial obturation reversibility test is the corner stone in asthma diagnosis. Patients with signs and symptoms suggestive of asthma but normal spirometry need additional tests like non-specific bronchoprovocations. Exercise-induced bronchi spasm is a feature of asthma and is the basis for exercise-test bronchi provocation in asthma diagnosis. The aim of this study was the comparison of clinical utility of obturation reversibility test and exercise provocation test in asthma diagnosis in patients with normal spirometry values., Methods and Material: The study was comprised of 77 subjects: 47 suspected to have asthma on history and 30 healthy volunteers. The inclusion criterion was: normal spirometry values. The obturation reversibility test was carried out in the study group. All participants had exercise test based on bicycle ergometer. The burden was adjusted so that the heart rate was at the submaximal level throughout the whole procedure. Spirometry values and peak expiratory flow (mini-Wright meter) were measured right after completion of the test and 5, 10, 15 and 20 minutes after completion of the test. The exercise test was considered positive when FEV1 declined by 15% or PEF declined by 20% in comparison to the initial value, respectively., Results: The obturation reversibility test was positive in 15 (31.9%) and negative in 32 (68.1%) patients from the study group. In the study group exercise test was positive according to FEV1 decline in 35 (74.5%) subjects, and only in 18 (38.3%) if PEF decline was a criterion. In the control group just 1 (3.3%) test turned out positive by FEV1 change and 3 (10%) were positive if PEF decline was measured. On the basis of positive exercise test and patient history the diagnosis of bronchial asthma was established in 35 (74.4%) patients. Among them--24 had sporadic asthma, 8 mild chronic asthma and 3 moderate chronic asthma., Conclusions: 1. Exercise test is a valuable diagnostic tool in patients with history suggestive of asthma and normal spirometry results and negative obturation reversibility test. 2. The parameter for the exercise test that best separate asthma and control group was FEV1.

Porcine galanin (pGAL), its 15-amino-acid-residue fragment and five new analogues modified in positions 4, 6 or 14 were tested for their effects on glucose-induced insulin secretion from isolated rat pancreatic islets of Langerhans. In vitro insulin secretion was studied during static incubation. All peptides were tested at two concentrations: 100 nM and 1 microM. The insulin level in the presence of 10 mM of glucose was a reference for all experiments. Our studies have shown that porcine galanin and its fragment GAL(1-15)NH2 at all concentrations tested inhibit glucose-induced insulin secretion. However, the modifications of the amino acid sequence of galanin caused changes in the interaction of GAL with its receptors, consequently yielding peptides that showed reverse activity as compared to pGAL or GAL(1-15)NH2. Finally, we have found three analogues: [Cit14]GAL(1-15)NH2, [Hse6]GAL(1-15)NH2 and [Cle4]GAL(1-15)NH2, which were able to stimulate glucose-induced insulin secretion and also antagonized inhibitory effect of pGAL. Other two galanin analogues: [D-Leu4]GAL(1-15)NH2 and [des-Leu4]GAL(1-15)NH2 showed a rather weak agonistic activity. Our observations suggest that positions: 4, 6 and 14 in the amino acid sequence of galanin may play an important role in the high-affinity binding of GAL to its receptors and biological action in perfused rat pancreas.