Strain and size combined effects on the GaN band structure: VEELS and DFT study

A nanoscale study of combined strain/size effects has been performed using monochromated valence electron energy-loss spectroscopy and density functional theory (DFT) calculations to locally explore the valence and conduction bands of a strained 2 nm GaN quantum well inserted between two fully relaxed AlN thick layers. Two main electronic transitions from the valence to the conduction band were experimentally detected and interpreted. The first transition was shown to be a collective oscillation (or plasmon), which was significantly blue-shifted in energy mainly due to the widening of the valence-band top-part. The second, however, had a single-particle character, that is: Ga-3d → Ga-4p, and was weakly affected by strain and size. In addition, our DFT calculations showed that strain and size can be adjusted separately to tune the GaN band-gap energy.

Tele-healthcare for diabetes management: A low cost automatic approach

In this paper, a telemedicine system for managing diabetic patients with better care is presented. The system is an end to end solution which relies on the integration of front end (patient unit) and backend web server. A key feature of the system developed is the very low cost automated approach. The front-end of the system is capable of reading glucose measurements from any glucose meter and sending them automatically via existing networks to the back-end server. The back-end is designed and developed using n-tier web client architecture based on model-view-controller design pattern using open source technology, a cost effective solution. The back-end helps the health-care provider with data analysis; data visualization and decision support, and allows them to send feedback and therapeutic advice to patients from anywhere using a browser enabled device. This system will be evaluated during the trials which will be conducted in collaboration with a local hospital in phased manner.

[Anesthesia for minimally invasive cardiac procedure]

The objectives are to present the different minimally invasive cardiac surgery techniques to repair the mitral valve, TAVI and MitraClip, as well as the implications for the anaesthetist. Evaluate retrospectively the anaesthesist methods, change in monitoring and how the patients are selected. The mitral valve repair by minithoracotomy and video-surgery requires selective left intubation and monitoring by TEE. The TAVI methods seem to be working best under local anaesthesia and sedation for haemodynamic and neurologic monitoring. The MitraClip surgery requires an extensive monitoring during and after surgery. In conclusion, the care of patients that are candidates for a TAVI requires the same level of expertise as anaesthesiology in cardiac surgery. The number of procedures performed under sedation will increase. These patients require multidisciplinary care (surgeons, cardiologists, sonographers and anaesthesiologists) due to comorbidities, and the possible haemodynamic, neurologic and vascular complications. These patients have an Euroscore greater than 20% and a STS score greater than 10%. In our experience, 80% of the cases are done femorally, 17% of the cases are done through the subsclavian artery (Corevalve(®)). 80% of the patients have surgery with a local anaesthesia and sedation. 20% of the patients get surgery with general anaesthesia. For the Edwards-Sapien(®) valve, when the femoral approach is impossible, the patient can get surgery with general anaesthesia using the transapical access.

Lactoferrin is synthesized by mouse brain tissue and its expression is enhanced after MPTP treatment

The presence of iron in brain tissue in increased concentrations in Parkinson's disease cases, where it might be responsible for oxidative stress, and the parallel observation that the iron transporter lactoferrin (Lf) was present in increased amounts in surviving neurons, led us to study the synthesis of Lf in a mouse model of Parkinson's disease. In this context, the origin and expression of brain Lf in normal, aged and MPTP (1-methyl-4-phenyl-1, 2,3,6-tetrahydropyridine)-treated mice were investigated. Lf immunostaining was observed mainly on microvessels in the cerebral cortex of the adult mice and to a greater extent in older mice. Lf immunoreactivity was also present in the hippocampus only in the aged mouse brains, associated with structures which seemed to be pyramidal neurons and fibers. After RT-PCR (polymerase chain reaction), Lf transcripts were found in mouse brain tissue whatever the age of the animals studied but the level of their expression was very low. No up-regulation of Lf was detectable during aging. Lf distribution and expression in the MPTP-induced Parkinsonian mouse model were also investigated. A marked depletion of dopamine (DA) occurred in the high dose MPTP-treated mice. The level of Lf expression was found to be markedly increased in the same animals and this up-regulation occurred on the first day after MPTP administration. When the brain was stressed by the neurotoxin MPTP, Lf expression increased in line with antioxidant enzymes such as catalase and gamma-glutamylcysteine synthetase, which may permit the protection of brain tissue from oxidative damage induced by the drug.

Lactoferrin is synthesized by mouse brain tissue and its expression is enhanced after MPTP treatment

The biological role and origin of human lactoferrin (Lf) within the brain in normal and disease processes are as yet uncharted. In this context the origin and expression of brain Lf in normal and MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine)-treated mice were investigated using immunohisto chemistry, PCR amplification and in situ hybridization. Lf immunostaining was observed both on sections of mouse lactating mammary gland, which was used as a positive control, and brains from young, adult and aged mice. Lf immunoreactivity was present in the pituitary gland, the hippocampus and the cortex of mouse brains and to a greater extent in older mice. After reverse transcription, Lf transcripts were also found in these brain sections. Lf distribution and expression in the MPTP-induced parkinsonian mouse model were next investigated. A marked depletion of dopamine and its metabolites: dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5-hydroxy indole acetic acid (5-HIAA) occurs in the high dose MPTP-treated mice. The level of Lf expression was found to be greatly increased in the same animals but Lf immunoreactivity detected in the same brain region was not found increased in the affected areas.

Changes in Helicobacter pylori ultrastructure and antigens during conversion from the bacillary to the coccoid form

In vitro, Helicobacter pylori converts from a bacillary to a full coccoid form via an intermediate U-shaped form. Organisms with a full coccoid form keep a double membrane system, a polar membrane, and invagination structures. Western blots (immunoblots) of sera from colonized patients show that some high-molecular-mass antigenic fractions are expressed only in coccoids. Conversely, fractions of 30 and 94 kDa were more intensively detected in the bacillary forms. These results suggest that (i) coccoid conversion is not a degenerative transformation and (ii) antigens specific to the coccoid forms are expressed in vivo.

Hyperthermia complicating tricyclic antidepressant overdose

We observed a 51-year-old woman who was admitted for severe amitriptyline overdose. Besides major cardiovascular complications, the patient developed severe hyperpyrexia with a central body temperature of more than 43 degrees C for 5 h. The patient died on day 3 from cardiocirculatory collapse and arrhythmias. Hyperthermia was unresponsive to cooling with ice water, gastric lavage, muscle relaxation, and dantrolene and bromocriptine administration. The possible mechanisms of refractory hyperthermia are discussed.

Structural determination of two N-linked glycans isolated from recombinant human lactoferrin expressed in BHK cells

A full-length cDNA coding for human lactoferrin was isolated from a mammary gland library and the recombinant protein was expressed in BHK cells as described by Stowell K. M. et al. [1991, Biochem. J. 276, 349-355]. Two N-linked glycans from purified recombinant lactoferrin were released by hydrazinolysis and analyzed by 400-MHz 1H-NMR spectroscopy. The identified structures corresponded to N-acetyllactosaminic biantennary glycans and were alpha-2,3-disialylated forms (80%) or alpha-2,3-monosialylated (20%) forms. Moreover, 70% of total glycans were alpha-1,6-fucosylated at the GlcNAc residue linked to asparagine. In regard to its glycan moiety, the recombinant glycoprotein is close to native lactoferrins from milk or leucocytes but shows specific structural features which should be taken into account prior to in vivo and in vitro biological studies.

Rat mammary-gland transferrin: nucleotide sequence, phylogenetic analysis and glycan structure

The complete cDNA for rat mammary-gland transferrin (Tf) has been sequenced and also the native protein isolated from milk in order to analyse the structure of the main glycan variants present. A lactating-rat mammary-gland cDNA library in lambda gt10 was screened with a partial cDNA copy of rat liver Tf and subsequently rescreened with 5' fragments of the longest clones. This produced a 2275 bp insert coding for an open reading frame of 695 amino acid residues. This includes a 19-amino acid signal sequence and the mature protein containing 676 amino acids and one N-glycosylation site in the C-terminal domain at residue 490. Phylogenetic analysis was carried out using 14 translated Tf nucleotide sequences, and the derived evolutionary tree shows that at least three gene duplication events have occurred during Tf evolution, one of which generated the N- and C-terminal domains and occurred before separation of arthropods and chordates. The two halves of human melanotransferrin are more similar to each other than to any other sequence, which contrasts with the pattern shown by the remaining sequences. Native rat milk Tf is separated into four bands on native PAGE that differ only in their sialic acid content: one biantennary glycan is present containing either no sialic acid residues or up to three. The complete structures of the two major variants were determined by methylation, m.s. and 400 MHz 1H-n.m.r. spectroscopy. They contain either one or two neuraminic acid residues (alpha 2-->6)-linked to galactose in conventional biantennary N-acetyl-lactosamine-type glycans. Most contain fucose (alpha 1-->6)-linked to the terminal non-reducing N-acetylglucosamine.

Expression of the lactotransferrin receptor during the differentiation process of the megakaryocyte Dami cell line

In order to determine whether the human lactotransferrin receptor recently described on platelets was also present on hematopoietic precursors, we investigated its presence and characteristics on the megakaryocytic Dami cell line. The reversible binding of human 5-(([2-(carbo(hydrazino)methyl]thio)acetyl)aminofluorescein-labele d lactotransferrin showed that such a receptor was only present on the subpopulation of the largest cells. The increase in numbers of large cells during culture was paralleled by a concurrent increase in lactotransferrin receptor positive cells. Scatchard analysis of the binding of [125I]-labeled lactotransferrin showed that a single affinity class of binding site was present (Kd = 446 +/- 40 nM) and that there were 52 +/- 3 x 10(5) sites per cell. The mouse monoclonal antibody DP5B3G10, specific for the human lactotransferrin receptor, allowed its characterization as a 105 kDa protein on Western blots. The same monoclonal antibody was used to separate the small and large cell subpopulations of Dami cells by panning. Separate culture of the small cells showed that the receptor appeared prior to and independent from endomitosis. In contrast, GPIb was expressed only by large megakaryocytes. The use of conditioned medium from cultures of whole Dami cell populations indicated that a soluble factor is involved in differentiation, but not in the appearance of the lactotransferrin receptor.

Molecular cloning and sequence analysis of bovine lactotransferrin

The screening of a bovine submaxillary gland cDNA library yielded 25 clones coding for bovine lactotransferrin. The nucleotide sequence of the longest insert contained a protein-coding region of 2115 nucleotides and a 3' non-coding region of 194 nucleotides followed by a poly(A) tract of about 55 nucleotides. The predicted peptide sequence included a 16-amino-acid signal sequence upstream of the first amino acid of the native protein. The identity of the clone was confirmed by matching the amino acid sequence predicted from the cDNA with the N-terminal and tryptic peptide sequences derived from purified bovine milk lactotransferrin, and also by similarity with human and murine lactotransferrins. The cDNA described corresponds to a 705-amino-acid-long preprotein that lacks the start methionine. The sequence of the secreted protein is 689 amino acids long and contains five potential glycosylation sites. Bovine lactotransferrin is 69% and 64% identical to human and murine lactotransferrins, respectively.