PubMed · 13374362
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1956-12-22. DAME EDITH BROWN.. https://pubmed.ncbi.nlm.nih.gov/13374362/
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UNLABELLED: Met-enkephalin is a pentapeptide belonging to the opioid system and like other opioid peptides is involved in phenomena associated with modulated pain perception, regulation of memory and emotional conditions, food and liquid consumption, regulation of immunological system and it has an impact upon digestive system motility, gastric and pancreatic secretion, metabolism of carbohydrates. Met-enkephalin concentration changes in liver tissue and plasma during liver disorders. It has been revealed that Met-enkephalin takes part in the etiopathogenesis of ascites and pruritus. Primary biliary cirrhosis (PBC) is a chronic inflammatory liver disease, its course involves the destruction of small and medium-sized bile ducts as a result of the process of granulation tissue growth developing in such diseases as fibrosis, liver cirrhosis development, and liver insufficiency. During the ending period of the PBC, clinical and biochemical symptoms of decompensation of liver cirrhosis occur. The objective of the study and paper was to make a comparison between the Met-enkephalin concentration rates in plasma and its content in liver tissue with the progress stage of PBC, which was assessed using clinical symptoms. The study was carried out in 40 female patients with PBC. PBC has been found by means of biochemical, serological investigations as well as histopathological liver bioptate estimation. The patietns with different causes of liver disorders have been excluded. Met-enkephalin concentration in plasma and content in liver tissue have been indicated in each patient. The control group consisted of 30 female patients treated in the Department of Gastroenterology with normal activity of indicative and cholestatic enzymes, and without any organic disorders. In the control group, the Met-enkephalin concentration rates in plasma were determined. Statistically significant difference has been indicated in Met-enkephalin plasma concentration between two patients groups: 23 patients with pruritus and 17 patients without it where (p = 0.0476). Statistically significant difference in Met-enkephalin concentration level in plasma and liver tissue in the group of 19 patients with liver failure symptoms (stadium IV and V according to Schaffner and Popper classification) and in the group of 21 patients without those symptoms (stadium I and II according to Schaffner and Popper classification) has been stated. For Met-enkephalin plasma concentration p = 0.002 and for Met-enkephalin liver tissue concentration p = 0.0214. CONCLUSIONS: 1. The Met-enkephalin concentration rates in serum of patients with the PBC is higher than in the control group; 2. In PBC patients' pruritus appears together with the increase of Met-enkephalin plasma concentration. 3. In PBC patients, when liver failure symptoms appear Met-enkephalin concentration increases in plasma, and it decreases in the liver tissue.
We introduce a novel heuristic global optimization method, energy landscape paving (ELP), which combines core ideas from energy surface deformation and tabu search. In appropriate limits, ELP reduces to existing techniques. The approach is very general and flexible and is illustrated here on two protein folding problems. For these examples, the technique gives faster convergence to the global minimum than previous approaches.
PURPOSE: A surface sensitive mass spectrometric technique: Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) was introduced to study the solid state instability of a methionine containing peptide caused by the oxidation of the methionine residue. METHODS: The oxidation of a neuropeptide Methinonine-Enkephalin (ME) in air and under UV acceleration was studied by ToF-SIMS. RESULTS: The apparent oxidation rate is defined by the peak ratio of oxidized molecular ion over unoxidized molecular ion. ME is oxidized at a faster rate to its sulfoxide derivative in the UV accelerated oxidation environment than in lab air. The calibration curve for evaluating the ionization probability ratio of the oxidized deprotonated molecular ion divided by the unoxidized deprotonated molecular ion was obtained. This could be used to extract the real oxidation rate of ME in the solid state. CONCLUSIONS: The preliminary results showed that ToF-SIMS with simple sample handling, fast data acquisition, together with excellent surface sensitivity and detection limit could be an applicable and convenient tool to study peptide reactions in the solid state such as oxidation and deamidation process.