3D-gradient coil structures for MRI designed using fuzzy membership functions

The design of high-performance gradient coils is essential for modern magnetic resonance imaging (MRI) applications. This work presents a new and alternative design methodology that explores three-dimensional (3D) solution space by combining fuzzy membership functions to model and re-shape the coil structure, given the magnetic field, electrical and mechanical constraints. The method was applied to design a short, unshielded asymmetric gradient coil for breast imaging. The resulting dome-shape coil has superior gradient performance compared to a standard fingerprint coil. New quadrupolar gradient coil designs for breast imaging are also obtained with the proposed method.

The age at diagnosis of type 1 diabetes continues to decrease in Belgian boys but not in girls: a 15-year survey

BACKGROUND

The age at clinical onset of type 1 diabetes is decreasing. Preliminary Belgian data suggested that this anticipation occurred preferentially in boys. We investigated whether this gender-specific anticipation could be confirmed over a 15-year observation period.

METHODS

In Antwerp, we studied incidence trends between 1989 and 2003 in 746 type 1 diabetic patients under age 40. For 2928 antibody-positive patients diagnosed nationwide during the same period, age at diagnosis was analysed according to gender and calendar year.

RESULTS

In Antwerp, the incidence of type 1 diabetes under age 15 increased significantly with time from 10.9/100 000/year in 1989-1993 to 15.8/100 000/year in 1999-2003 (p = 0.008). The rising incidence in children was largely restricted to boys under age 10 where the incidence more than doubled during the 15-year period (6.8/100 000/year in 1989-1993 vs 17.2/100 000/year in 1999-2003; p < 0.001). Such an increase was not found in girls under age 10 (p = 0.54). This selective trend toward younger age at diagnosis in boys was confirmed in the larger group of Belgian patients where the median age at diagnosis decreased in boys-but not in girls-from 20 years in 1989-1993 to 15 years in 1999-2003 (p < 0.001).

CONCLUSIONS

Over a 15-year observation period, a selective anticipation of clinical onset of type 1 diabetes was found in boys but not in girls. This suggests that an environmental factor may preferentially accelerate the sub-clinical disease process in young boys.

Mechanotransduction in lymphatic endothelial cells

Initial lymphatic vessel endothelial cells are connected to the surrounding elastic fibers by fibrillin anchoring filaments that have been hypothesized to favor interstitial fluid drainage in edema pulling apart interendothelial junctions. We hypothesized a biochemical mechanism involving mechanotransduction. This study was designed to verify whether a relation exists between focal adhesion molecules and anchoring filaments and whether they may transduce extracellular forces to the nucleus. We first performed an immunohistochemical study on human skin cryostat sections to evaluate whether fibrillin and alphav-beta3 integrins, FAK and fibrillin, or alphav-beta3 integrins and FAK co-localize in lymphatic endothelium. We observed that integrins and FAK co-localize and that fibrillin filament attachment sites to endothelial cells merge with these molecules. These data may suggest that fibrillin anchoring filaments are connected to endothelial cells through focal adhesions. Mechanotransduction was investigated applying static stretching to bovine thoracic duct segments and lymphatic endothelial cells cultured on elastic membranes and immunohistochemically evaluating the expression of ERK1/2. Under stretching conditions, ERK1/2 labels the nucleus. Western blotting on cultured cells confirmed the presence of ERK1/2 in stretched cells. Based on our data we speculate that anchoring filaments may trigger a focal adhesion-mediated cascade of mechanotransduction toward the nucleus for genetic modulation and thus contribute to endothelial adaptation to interstitial requirements.

Video-assisted laryngoscopy: a useful adjunct in endotracheal intubation

The difficult airway is the single most important cause of anaesthesia-related morbidity and mortality and most catastrophes are due to unexpected difficulty, which are more likely in emergencies. We report a difficult airway scenario in a patient with a high energetic trauma and used several techniques for the "can't intubate, can't ventilate scenario". Eventually, successful intubation was obtained with the video-assisted laryngoscope.

Altered distribution and levels of cathepsinD and cystatins in amyotrophic lateral sclerosis transgenic mice: Possible roles in motor neuron survival

In amyotrophic lateral sclerosis (ALS) there is a selective degeneration of motor neurons leading to muscle paralysis and death. The mechanism underlying cell demise in ALS is not fully understood, but involves the activation of different proteolytic enzymes, including the caspase family of cysteine proteases. We have here studied whether other proteases, such as the cathepsins, residing in lysosomes, and the cathepsin inhibitors, cystatinB and -C are changed in ALS. The expression and protein levels of the cathepsinB, -L and -D all increased in the spinal cord in ALS mice, carrying the mutant copper/zinc superoxide dismutase (SOD1) gene. At the cellular level, cathepsinB and -L were present in ventral motor neurons in controls, but in the ALS mice cathepsinB was also expressed by glial fibrillary acidic protein (GFAP) positive astrocytes. The distribution of the aspartic protease, cathepsinD also changed in ALS with a loss of the lysosomal staining in motor neurons. Inhibition of caspases by means of X-chromosome-linked inhibitor of apoptosis protein (XIAP) overexpression did not inhibit cleavage of cathepsinD in ALS mice, suggesting a caspase-independent pathway. Expression of cystatinB and -C increased slightly in the ALS spinal cords. Immunostaining showed that in ALS, cystatinC was present in motor neurons and in GFAP positive astrocytes. CystatinB that is a neuroprotective factor decreased in motor neurons in ALS but was expressed by activated microglial cells. The observed changes in the levels and distributions of cathepsinD and cystatinB and-C indicate a role of these proteins in the degeneration of motor neurons in ALS.

Biological and prognostic role of acid cysteine proteinase inhibitor (ACPI, cystatin A) in non-small-cell lung cancer

BACKGROUND

Acid cysteine protease inhibitor (ACPI) is an intracellular protein, often linked to neoplastic changes in epithelium and thought to have an inhibitory role in malignant transformation.

AIM

To analyse the expression and prognostic role of ACPI in non-small-cell lung cancer (NSCLC).

METHOD

Histological samples from 199 patients with resected NSCLC were stained immunohistochemically for the expression of ACPI in normal and preneoplastic bronchial epithelium, and in various types of lung carcinomas.

RESULTS

A normal bronchial epithelium showed positive staining for ACPI in the basal cells, whereas the upper two-thirds of the dysplastic epithelium was ACPI positive. High staining for ACPI was found in 74% (91/123) of squamous-cell carcinomas, whereas 16% (8/49) of adenocarcinomas and 30% of (8/27) large-cell carcinomas showed the high expression of ACPI (p<0.001). Among squamous-cell carcinomas, low expression of ACPI was correlated with poor tumour differentiation (p=0.032). In the whole tissue, reduced expression of ACPI was associated with tumour recurrence (p=0.024). In overall survival (OS) and disease-free survival (DFS) analyses, the histological type of the tumour (both p<0.001) and stage of the tumour (p=0.001, p=0.013, respectively) were related to patient outcome. Low expression of ACPI in tumour cells was associated with poor OS and DFS (p<0.041, p=0.004, respectively). In multivariate analysis, ACPI did not retain its prognostic value, whereas the traditional factors were the most important prognostic factors.

CONCLUSIONS

ACPI expression is linked with the malignant transformation of the bronchial epithelium and predicts a risk of tumour recurrence as well as poor rate of survival for the patients. However, ACPI does not have any independent prognostic value in NSCLC.

Novel amphiphiles with preorganized functionalities-formation of Langmuir-films and efficiency in mineral flotation

Based on the principle of supramolecular preorganization, three different types of new oligofunctional surfactants have been designed and prepared differing in both the degree of conformational flexibility and the hydrophilic-lipophilic balance of their structures due to the chosen building blocks including rather rigid and shape-persistent backbones or a dendritic subunit. Surface-active properties of the oligofunctional surfactants involving critical micellization concentration, surface tension at cmc, effectiveness of surface tension reduction, and the efficiency of adsorption were determined by use of the surface tension isotherms, respectively. In particular the amino-acid-based amphiphiles show remarkable surface-active properties with the adsorption at the air/water interface and also the aggregation to micelles starting at very low concentration. By analysis of the surface pressure-surface area isotherms interesting information on the packing behavior and orientation of the amphiphilic molecules in relation to the molecular structure could be obtained. Moreover, limiting area and collapse pressure of the Langmuir-films were determined. Morphological observation of the dynamic process of monolayer compression at the air/water interface was carried out by Brewster angle microscopy illustrating several phase states visualized as snap shots. Furthermore, the effectiveness of the new surfactants acting as collecting agents in the process of flotation using the model mineral fluorite was studied. A surprisingly high recovery of the mineral was obtained for the surfactants with constricted flexibility. The flotation plots clearly manifest that bundling of surfactant subunits by tethering to an aromatic core or by dendritic branching is profitable, indicating that effects of preorganization of the oligofunctional surfactant molecules are important.

Hyaluronan and sulphated hyaluronan micropatterns: effect of chemical and topographic cues on lymphatic endothelial cell alignment and proliferation

While tissue engineered blood vessels have entered surgical practice, the construction of artificial lymphatic vessels has never been attempted due to the small dimensions and fragility of lymphatic vessels. A possible alternative would be to obtain a new growth of interrupted lymphatic vessels. We have previously reported that lymphatic endothelial cells align when cultured on striped micropatterns of hyaluronan (Hyal) and aminosilanized glass. We here report a comparative study in which lymphatic endothelial cells have been plated on micropatterns with stripes of different width and height obtained by the photoimmobilization of Hyal and its sulphated derivative (HyalS) on aminosilanized glass to verify whether their response correlated with surface-chemistry andlor topography. On Hyal micropatterns, cells adhered to aminosilanized glass, avoiding Hyal stripes and molding their shape in accordance to the micropattern topography. Stress fibers, integrins and focal adhesion kinase organized accordingly. HyalS micropatterns with the same topography were unable to guide cell response, cells randomly adhered to HyalS and glass stripes, and polarization was attained only by increasing stripe height. These data indicate that surface chemistry is the main cue responsible for lymphatic endothelial cell guidance. When surface chemistry of stripes promotes cell adhesion as well as that of the substrate, topographical parameters become prevalent. Micropatterns with defined chemical and topographical properties may contribute to the design of new platforms for controlled cell growth in tissue engineering of lymphatic vessels.