Effect of neurotensin on pancreatic function in man

The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs.     

Identification and probiotic properties of lactobacilli isolated from two different fermented beverages

Purpose

Scientific information regarding the microbial content and functional aspects of fermented beverages traditionally produced in certain parts of Europe are scarce. However, such products are believed to have some health benefits and might contain functional bacterial strains, such as probiotics. The aim of the study was to identify such lactic acid bacteria strains isolated from water kefir and, for the first time, from braga, a Romanian fermented beverage made of cereals.

Methods

Lactic acid bacteria (LAB) were identified to species level based on (GTG)₅-PCR fingerprinting and 16S rRNA gene sequencing. Selected strains were screened for their antibacterial activity and probiotic potential.

Results

Eight isolates belonging to seven Lactobacillus species were recovered from the two drinks. The identification of LAB involved in the fermentation of braga (Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus delbrueckii) is firstly reported here. Five of the Lactobacillus isolates showed antibacterial activity against pathogenic bacteria, including Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Salmonella enterica. Moreover, most of them showed a good resistance to pH 2.5 and some survived at high concentrations of bile salts (up to 2%). Two L. plantarum isolates were able to inhibit all the indicator strains, and showed the best viability (about 70%) after a sequential treatment simulating the passage through the gastrointestinal tract.

Conclusion

Based on the results, the most promising candidates for designing new probiotic products are: L. plantarum BR9 from braga and L. plantarum CR1 from water kefir.

     

Production kinetics of acidophilin 801, a bacteriocin produced by Lactobacillus acidophilus IBB 801

Lactobacillus acidophilus IBB 801 produces a small bacteriocin, designated acidophilin 801. Studying the relationship between growth and bacteriocin biosynthesis revealed primary metabolite kinetics of bacteriocin production with a peak activity at the end of the exponential growth phase followed by a decrease during the stationary phase. Both microbial growth and bacteriocin production was inhibited by lactic acid. Whereas volumetric bacteriocin production (activity units (AU) ml(-1)) was favoured under pH-controlled conditions, bacteriocin titres rapidly decreased because of strong adsorption of the bacteriocin molecules to the producing cells under less acidic conditions.     

Human gliosarcoma-associated ganglioside composition is complex and distinctive as evidenced by high-performance mass spectrometric determination and structural characterization

Gangliosides (GGs), involved in malignant alteration and tumor progression/invasiveness, are considered as tumor biomarkers or therapeutic targets. Here, we describe the first systematic GG composition characterization in human gliosarcoma versus normal brain tissue using our recently developed mass spectrometry (MS) methods, based on nano-electrospray (nano-ESI), Fourier-transform ion cyclotron resonance (FT-ICR), and chip nano-ESI quadrupole time-of-flight (QTOF), complemented by thin-layer chromatographic (TLC) analysis and quantification. Combined MS enabled detection and structural assignment of 73 distinct GG species: many more than reported so far for investigated gliomas. Apart from the 7.4-times lower total GG content, gliosarcoma contained all major brain-associated species, however, in very altered proportions, exhibiting a highly distinctive pattern: GD3 (48.9%)>GD1a/nLD1>GD2/GT3>GM3>GT1b>GM2>GM1a/GM1b/nLM1>LM1>GD1b>GQ1b. MS also revealed abundant O-Ac-GD3; its sequencing provided structural evidence to postulate a novel O-Ac-GD3 isomer O-acetylated at the inner Neu5Ac-residue, previously not structurally confirmed. The high sensitivity and mass accuracy permitted the assignment of unusual minor species: GM4, Hex-HexNAc-nLM1, Gal-GD1, Fuc-GT1, GalNAc-GT1, O-Ac-GM3, di- O-Ac-GD3O-Ac-GD3, and O-Ac-GT3, not previously reported as glioma-associated. The gliosarcoma-expressed GA2 might represent a marker distinguishing astrocytic from oligodendroglial tumors. This is, to our knowledge, so far the most complete GG composition characterization of certain glioma, which demonstrates that our MS-based approach could provide essential structural information relevant to glycosphingolipid role(s) in brain tumor biology, differential diagnosis/prognosis and novel treatment concepts.     

The amino acid tryptophan prevents the biosynthesis of dermatan sulfate

An important part of the biosynthesis of proteoglycans is the epimerization of glycosaminoglycan chains. As a consequence of the conversion of chondroitin sulfate (CS) to dermatan sulfate (DS), the glycosaminoglycans become more flexible and enable DS to perform more sophisticated signaling functions. In a recent study, we generated a chimera (S222A) composed of a truncated form of a DS (decorin) and CS (CSF-1) containing proteoglycan and analyzed the influence of the core protein on the extent of epimerization. C-terminal truncation constructs from S222A enabled us to identify an amino acid segment that lies within the CSF-1 part which prevents DS synthesis. Co-localization experiments using S222A-HA and DCN-Flag showed different intracellular localizations for the proteoglycans during biosynthesis. A data base search revealed a sequence motif (TNWVP) within the CSF-1 moiety that is found to be important in other proteoglycans. A single substitution of tryptophan-216 to leucine (W216L) in the chimera S222A increased the amount of l-IdoA to 12-16%. Co-localization with an ER-marker demonstrated that the biosynthesis of recombinant decorin is similar to the chimera S222A and S222A(W216L) in HEK293 cells. Co-staining of S222A-HA and S222A(W216L)-Flag showed different intracellular localizations for the proteoglycans. A more detailed analysis of the glycosaminoglycans reflects a similar total sulfate content for S222A and S222A(W216L). The 4/6 sulfation ratio was similar for decorin and S222A, but altered for S222A(W216L). However, the binding of fibroblasts growth factor-1 to CS/DS was only partially dependent on epimerization. These results are consistent with the model in which the core protein, via the amino acid tryptophan, is responsible for routing to subcellular compartments with or without sufficient access to chondroitin-glucuronate 5-epimerase.     

Peripartum Cardiomyopathy Presenting With Ventricular Tachycardia: A Rare Presentation

A 25-year-old previously asymptomatic pregnant woman at 36 weeks'' gestation was noticed to have repetitive monomorphic ventricular tachycardia. A dilated left ventricle with moderately reduced systolic function was found on echocardiographic examination. This is a very rare presentation of peripartum cardiomyopathy (PPCMP) presenting with repetitive monomorphic ventricular tachycardia.     

Early stage fetal neocortex exhibits a complex ganglioside profile as revealed by high resolution tandem mass spectrometry

In this study we report on the first mass spectrometric (MS) investigation of gangliosides and preliminary assessment of the expression and structure in normal fetal neocortex in early developmental stages: 14th (Neo14) and 16th (Neo16) gestational weeks. Ganglioside analysis was carried out using a hybrid quadrupole time-of-flight (QTOF) MS with direct sample infusion by nanoelectrospray ionization (nanoESI) in the negative ion mode. Under optimized conditions a large number of glycoforms i.e. 75 in Neo14 and 71 in Neo16 mixtures were identified. The ganglioside species were found characterized by a high diversity of the ceramide constitution, an elevated sialylation degree (up to pentasialylated gangliosides-GP1) and sugar cores modified by fucosylation (Fuc) and acetylation (O-Ac). Direct comparison between Neo14 and Neo16 revealed a prominent expression of monosialylated structures in the Neo16 as well as the presence of a larger number of polysialylated species in Neo14 which constitutes a clear marker of rapid development-dependant changes in the sialylation. Also the MS screening results highlighted that presumably O-acetylation process occurs faster than fucosylation. CID MS/MS under variable collision energy applied for the first time for structural analysis of a fucosylated pentasialylated species induced an efficient fragmentation with generation of ions supporting Fuc-GP1d isomer in early stage fetal brain neocortex.