A randomised controlled study comparing conventional and magnetic guidewires in a two-dimensional branching tortuous phantom simulating angulated coronary vessels.

OBJECTIVES: To directly compare the magnetic navigation system (MNS) guidewires with conventional guidewires in branching tortuous phantoms with operators of varying MNS and percutaneous coronary intervention experience. BACKGROUND: Vessel tortuosity, angulation, and side branches remain limiting factors in coronary interventions. The MNS addresses these limitations by precisely directing the tip of a magnetised guidewire in vivo aided by two permanent adjustable external magnets. METHODS: Crossing and fluoroscopy times of six operators were evaluated in five tortuous Perspex(R) phantom vessels in three consecutive attempts. Standard guidewire (SG) usage was unrestricted. Two 2nd generation magnetic guidewires (MG) were used. Failure was noted if the cross was unsuccessful within 5 min. RESULTS: The magnetic navigation was vastly superior to SG techniques with increasingly tortuous phantoms. It dramatically decreased both the crossing and fluoroscopy times with maximal reduction from 201.7 +/- 111 to 36.4 +/- 13 sec, P < 0.001 and 204.7 +/- 24 to 47.2 +/- 19 sec, P < 0.001, respectively. The MNS had a 98.8% procedural success rate compared to 68% with SG techniques. Moreover it considerably limited the amount of wire usage from 5.5 to 1.3. Operators with prior MG experience performed significantly better than those without, except in the simplest phantom where the difference was nonsignificant (33.8 +/- 13 sec vs. 41.7 +/- 17 sec, P = 0.2). CONCLUSION: MNS significantly reduces both the crossing and fluoroscopy times in tortuous coronary phantom models achieving excellent success rates with dramatic reductions in guidewire usage. Operators with prior MNS experience had an advantage over the inexperienced.     

The Maillard reaction in demineralized dentin in vitro

The Maillard reaction between carbohydrate and protein has been proposed as a cause of the browning of carious lesions. The aim of the present investigation was to determine the occurrence of this reaction in bovine dentin collagen in vitro and to establish the effect of the reaction on the proteolytic degradation of bovine dentin collagen in vitro. Slices of demineralized bovine dentin were incubated with 0.2 M glucose or buffer for 10 weeks at 37°C. The formation of initial (furosine) and advanced (pentosidine) products of the Maillard reaction in dentin exposed to glucose was confirmed by HPLC. After reduction with NaBH₄ to prevent intermediate Maillard products from further reaction, slices were either degraded with collagenase for fluorescence measurement or incubated with trypsin or pepsin to assess enzymatic degradation. Fluorescence characteristic for the Maillard reaction increased in glucose-exposed slices. Degradation of collagen by pepsin, but not by trypsin, was greatly depressed following glucose pretreatment. This may indicate an altered sensitivity to proteolytic degradation; the Maillard reaction thus has a potential role in caries arrestment.     

B cell antigen receptor cross-linking induces tyrosine phosphorylation and membrane translocation of a multimeric Shc complex that is augmented by CD19 co-ligation

The SH2 domain-containing transforming Shc protein has been implicated in mitogenic signaling via several surface receptors through p21^ras. Following tyrosine phosphorylation by either receptor or non-receptor tyrosine kinases, Shc may interact with the adaptor protein Grb2, which is linked to Sos1, a guanine nucleotide exchange factor for human ras. Ligation of the antigen receptor complex on B cells (BCR) is known to activate various intracellular signaling pathways, which may accumulate in mitogenic responses. With respect to the initial steps, the activation of BCR-associated non-receptor tyrosine kinases appears to be indispensible. In this report we show that Shc proteins become tyrosine phosphorylated after BCR ligation on both transformed and normal human B cells. This is accompanied by the association of Shc with Grb2 proteins and a yet unidentified 145-kDa tyrosine phosphorylated protein. Subcellular fractionation revealed that this activation-induced multimeric Shc complex rapidly translocates towards the plasma membrane. Co-ligation of the BCR with the CD19 molecule results in a marked increase of these events, whereas CD19 cross-linking alone does not induce Shc tyrosine phosphorylation or translocation. Thus, in B cells the Shc complex may represent a molecular junction between the BCR and the mitogenic p21^ras cascade.     

Identification and susceptibility testing of Enterobacteriaceae and Pseudomonas aeruginosa by direct inoculation from positive BACTEC blood culture bottles into Vitek 2

Inoculation of an automated system for rapid identification (ID) and antimicrobial susceptibility testing (AST) directly from positive blood culture bottles will reduce the turnaround time of laboratory diagnosis of septicemic patients, which benefits clinical outcome and decreases patient costs. Direct test results, however, must always be confirmed by testing a pure overnight culture, which is the "gold standard." We studied the accuracy of direct testing versus repeat testing in order to investigate the possibility of refraining from repeat testing. We also assessed the clinical risk of reporting results based on direct testing only. We inoculated Vitek 2 (bioMérieux) directly from 410 positive BACTEC 9240 (BD) blood culture bottles containing gram-negative rods and studied the ID and AST results. In a comparison of direct inoculation with the standard method, a total of 344 isolates of Enterobacteriaceae and Pseudomonas aeruginosa were tested, and 93.0% were correctly identified. Of the 39 (10.2%) samples that contained bacilli not identifiable by Vitek 2, only 1 gave a conclusive, correct result. The overall MIC agreement among 312 isolates was 99.2%, with 0.8% very major and 0.02% major error rates. Of only three (polymicrobial) samples, the direct susceptibility pattern would be reported to the clinician as too sensitive. Vitek 2 results obtained from direct inoculation of blood culture bottles containing gram-negative bacilli are safe enough for immediate reporting, provided that ID and AST are consistent. Repeat testing is not necessary, unless Gram stain or overnight subculture results raise doubt about the purity of the culture.     

The CR2/CD19 complex on human B cells contains the src-family kinase Lyn

The complement receptor 2 (CR2 or CD21) can be found in non-covalentassociation with the Blymphocyte specific CD19 complex at thesurface of mature human B cells. Upon ligation of the B cellantigen receptor complex (BCR), members of the CR2-CD19 complexmay associate with membrane immunoglobulin (mlg). Moreover,CD19 and CD21 ligands, either murine mAb, C3d fragments or Epstein—Barrvirus, are known to have profound effects on B cell activation.We here show that CD19 is tightly linked to the non-receptorsrc kinase Lyn and that the CD19 glycoprotein itself servesas a substrate for a yet undefined serine/threonine kinase presentwithin the complex. In the process of antigen recognition, mlgand the CR2-CD19 complex may bind different sites of a complement-opsonizedantigenic particle. We hypothesize that in this process, approximationto the BCR allows CD19-associated Lyn kinase to phosphorylatepotential substrates within the antigen—receptor complex,thereby effecting its coupling to the intracellular compartment.     

Social support and the persistence of complaints in chronic fatigue syndrome

BACKGROUND: Several studies suggested that the surroundings of chronic fatigue syndrome (CFS) patients are of importance in the persistence of complaints. Contrary to what was expected, participation in support groups has not led to clinical improvement. The purpose of the present study was to describe social support in CFS patients as compared with other fatigued and non-fatigued groups. Further, changes in social support and the influence of social support on the course of CFS over a period of more than 1 year were studied in patients with and without treatment. METHODS: Baseline data were assessed in 270 CFS patients, 150 disease-free breast cancer patients, 151 fatigued employees on sick-leave and 108 healthy subjects using the Social Support List and Significant Others Scale. CFS patients were followed in cognitive behaviour therapy (CBT), guided support groups and natural course at 8 and 14 months. RESULTS: CFS patients and fatigued employees reported more negative interactions and insufficiency of supporting interactions than cancer patients and healthy controls. No differences in frequency of supporting interactions were found. Negative interactions decreased significantly after treatment with CBT, but did not change in support groups or natural course. In the natural course, higher fatigue severity at 8 months was predicted by more negative interactions at baseline. CONCLUSIONS: In CFS patients and fatigued employees, social support is worse than in disease-free cancer patients and healthy controls. Lack of social support was identified as a new factor in the model of perpetuating factors of fatigue severity and functional impairment in CFS.     

Biofeedback treatment is ineffective in neurogenic fecal incontinence

PURPOSE: This study was undertaken to assess biofeedback treatment (active sphincter exercises under direct electromyography vision) in neurogenic fecal incontinence. METHODS: Twelve patients with neurogenic fecal incontinence have been studied prospectively. External sphincter contractions were exercised under direct electromyographic vision twice per day for 30 minutes during 12 weeks. Manometry was done at the beginning and after 12 weeks of training to evaluate objectively changes in sphincter functions. RESULTS: No patient experienced any improvement in fecal control. Mean resting pressure increased from 7 to 9 kPa and mean squeeze pressure from 3.9 to 4.9 kPA, which was of no statistical significance (P =0.20 and P =0.46, respectively). CONCLUSIONS: External sphincter contraction exercises under direct electromyographic vision are not effective in neurogenic fecal incontinence. Degree of continence does not improve, and external sphincter function is not increased significantly.     

Connectome spectrum electromagnetic tomography: A method to reconstruct electrical brain source networks at high-spatial resolution

Connectome spectrum electromagnetic tomography (CSET) combines diffusion MRI-derived structural connectivity data with well-established graph signal processing tools to solve the M/EEG inverse problem. Using simulated EEG signals from fMRI responses, and two EEG datasets on visual-evoked potentials, we provide evidence supporting that (i) CSET captures realistic neurophysiological patterns with better accuracy than state-of-the-art methods, (ii) CSET can reconstruct brain responses more accurately and with more robustness to intrinsic noise in the EEG signal. These results demonstrate that CSET offers high spatio-temporal accuracy, enabling neuroscientists to extend their research beyond the current limitations of low sampling frequency in functional MRI and the poor spatial resolution of M/EEG.     

New insights into the base catalyzed depolymerization of technical lignins: a systematic comparison

A first systematic approach on the base catalyzed depolymerization (BCD) of five technical lignins derived from various botanical origins (herbaceous, hardwood and softwood) and covering the main three industrial pulping methods (soda, kraft and organosolv) is reported. This study provides a first of its kind in-depth quantification and structural characterization of two main BCD fractions namely lignin oil and lignin residue, describing the influence of the BCD process conditions. Depolymerization is evaluated in terms of lignin conversion, lignin oil yield, phenolic monomer selectivity and the production of lignin residue and char. Lignin oils were extensively characterized by size exclusion chromatography (SEC), GC-MS, GC-FID, ¹³C-NMR, HSQC NMR and elemental analysis. GC × GC-FID was used to identify and quantify distinct groups of monomeric compounds (methoxy phenols, phenols, dihydroxy-benzenes) in the lignin oil. The lignin oil yields (w/w) ranged from 20–31% with total monomer contents ranging from 48 to 57% w/w. SEC analysis indicated the presence of dimers/oligomers in the lignin oil, which through HSQC NMR analysis were confirmed to contain new, non-native interunit linkages. ¹³C NMR analyses of the lignin oils suggest the presence of diaryl type linkages (i.e. aryl–aryl, aryl C–O) evidencing deconstruction and recombination of lignin fragments during BCD. Irrespective of the lignin source, a residue, often regarded as ‘unreacted’ residual lignin was the main product of BCD (43 to 70% w/w). Our study highlights that this residue has different structural properties and should not be considered as unreacted lignin, but rather as an alkali soluble condensed aromatic material. HSQC, DEPT-135, ¹³C, and ³¹P NMR and SEC analyses confirm that the BCD residues are indeed more condensed, with increased phenolic hydroxyl content and lower molecular weights compared to all feed lignins. Subsequent BCD of solid residual fractions produced only low oil yields (6–9% w/w) with lower phenolic monomer yields (4% w/w) compared to original lignin, confirming the significantly more recalcitrant structure. Our study improves the overall understanding of the BCD process, highlights important feedstock-dependent outcomes and ultimately contributes to the complete valorization of BCD-derived lignin streams.

Towards a lignin BCD biorefinery! Overall understanding of the BCD process, feedstock-dependent fractionation results, complete valorization of BCD-derived lignin streams.