Automated detection, 3D segmentation and analysis of high resolution spine MR images using statistical shape models

Recent advances in high resolution magnetic resonance (MR) imaging of the spine provide a basis for the automated assessment of intervertebral disc (IVD) and vertebral body (VB) anatomy. High resolution three-dimensional (3D) morphological information contained in these images may be useful for early detection and monitoring of common spine disorders, such as disc degeneration. This work proposes an automated approach to extract the 3D segmentations of lumbar and thoracic IVDs and VBs from MR images using statistical shape analysis and registration of grey level intensity profiles. The algorithm was validated on a dataset of volumetric scans of the thoracolumbar spine of asymptomatic volunteers obtained on a 3T scanner using the relatively new 3D T2-weighted SPACE pulse sequence. Manual segmentations and expert radiological findings of early signs of disc degeneration were used in the validation. There was good agreement between manual and automated segmentation of the IVD and VB volumes with the mean Dice scores of 0.89 ± 0.04 and 0.91 ± 0.02 and mean absolute surface distances of 0.55 ± 0.18 mm and 0.67 ± 0.17 mm respectively. The method compares favourably to existing 3D MR segmentation techniques for VBs. This is the first time IVDs have been automatically segmented from 3D volumetric scans and shape parameters obtained were used in preliminary analyses to accurately classify (100% sensitivity, 98.3% specificity) disc abnormalities associated with early degenerative changes.

Understanding the role parents play in tennis success: a national survey of junior tennis coaches

OBJECTIVES

To assess coaches' perceptions about the role of parents and their positive and negative behaviours in junior tennis.

METHODS

A national survey of 132 United States junior tennis coaches was completed. The extent and seriousness/impact of parent-child interaction problems and positive behaviours were rated.

RESULTS

Parents were perceived as very important for junior tennis success. Most parents (59%) that these coaches had worked with were seen as having a positive influence on their player's development. However, the respondents also felt that 36% of parents negatively influenced their child's development. Positive parental behaviours included providing logistical, financial, and social-emotional support, as well as tennis opportunities and unconditional love. Negative parent behaviours included overemphasising winning, holding unrealistic expectations, and criticising their child.

CONCLUSIONS

Findings are discussed relative to current sport parenting and athletic talent development research and theorising. The need to educate parents is emphasised.

Analysis of electrotonic coupling in patterned neuronal networks

Microcontact printing of laminin is known as an efficient approach for guiding neuronal cell migration and neurite outgrowth on artificial surfaces. In the present study, ultrathin (approximately 250 microm) brain stem slices of Sprague-Dawley rats (E15-E18) were cultured on laminin-patterned substrates, such that neuronal cells migrating out of the slices formed grid-shaped neuronal networks along the geometry defined by the pattern. The interconnections between neighbouring pairs of neurons within these artificial networks were assessed electrophysiologically by double patch-clamp recordings and optically by microinjection of fluorescent dyes. Both functional and electrotonic synapses were detected. Based on the recorded data and simulations in PSpice, an electrical model for electrotonically coupled cells was derived. In this model the neuritic pathway is described as a cylindric cable, and gap junctions are represented by an ohmic resistor. Applying this model in the data analysis, the average inner radius of neurites could be determined to be approximately 0.1 microm. In addition, evidence was found for a correlation between the path-width of the applied pattern and the diameter of neurites growing along these paths.

Electrophysiological recordings of patterned rat brain stem slice neurons

Dissociated neuronal cultures on substrates patterned with extracellular matrix (ECM) proteins have yielded much information in the past. However, although the culture of brain slices has many advantages over dissociated neuronal cultures, its feasibility on patterned substrates has not been demonstrated to date. In the present study, neuronal outgrowth from brain stem slices onto homogeneous control substrates, and onto laminin structures of grid- and line-shape was achieved. Cultures were evaluated by means of phase contrast microscopy, antibody staining, and patch-clamp measurements. Only patterns with line sizes of more than 4 microm yielded satisfactory neuronal outgrowth. The size of the nodes in the pattern influenced the nodal compliance of the spreading cells and the amount of unstructured overgrowth. Best grid patterns were 4 microm lines and 10 microm nodes, best line patterns were 4 microm lines and 20 microm nodes. On patterned substrates, average sodium and potassium currents were reduced by approximately 50% compared to controls, whereas area-normalized ion-currents were in the same order of magnitude. This indicates that as a consequence of the pattern-enforced geometrical confinement, neurons tend to have a smaller surface. In addition, neurons on patterned substrates were rapidly covered with glial overgrowth. This was shown by antibody staining.

Aligned microcontact printing of biomolecules on microelectronic device surfaces

Microcontact printing (muCP) of extracellular matrix proteins is a fascinating approach to control cell positioning and outgrowth, which is essential in the development of applications ranging from cellular biosensors to tissue engineering. Microelectronic devices can be used to detect the activity from a large number of recording sites over the long term. However, signals from cells can only be recorded at small sensitive spots. In this paper, we present an innovative setup to perform aligned muCP of extracellular matrix proteins on microelectronic devices in order to guide the growth of electrogenic cells specifically to these sensitive spots. Our system is based on the combination of a fine-placer with redesigned micro stamps having a rigid glass cylinder as backbone for attachment in the alignment tool. Alignment is performed moving the device with an optical table under microscopic control of the superimposed images from stamp and device surface. After successful alignment, the stamp is brought into contact with the device surface by means of a high-precision lever. With our setup, we were able to pattern up to 40 devices per hour. A lateral alignment accuracy of < 2microm has been achieved. Aligned neuronal growth on patterned devices was demonstrated with dissociated hippocampal neurons.

Spot compliant neuronal networks by structure optimized micro-contact printing

Neuronal cell growth in vitro can be controlled with micropatterned structures of extracellular matrix proteins such as laminin. This technique is a powerful tool for studying neuronal cell function in order to increase experimental reproducibility and to specifically design innovative experimental setups. In this paper the correlation between the structural dimensions of the ECM pattern and the shape of the resulting cellular network is analyzed. The aim of the present study was to position neuronal cell bodies as precisely as possible and to induce directed cell differentiation. PCC7-MzN cells were cultured on laminin patterns. The line width, node size and gap size in-between cell adhesion sites was varied systematically. Micrographs of the samples were taken and statistically analyzed using Student's t-test and linear correlation methods. Precise cell positioning has successfully been performed and evidence for controlled neuronal polarization has been found. With a structure geometry of 4 microm line width, 20 microm node size and 10 microm gap size a nodal compliance of 86% (+/- 10%) has been achieved.

Modulation of the growth and guidance of rat brain stem neurons using patterned extracellular matrix proteins

Dissociated neuronal cultures on substrates patterned with extracellular matrix (ECM) proteins have yielded much information regarding the physiological characteristics of neuronal cells behaviour in vitro. However, neuronal patterning using long term embryonic brain slice cultures has not been comprehensively demonstrated to-date. Structuring was performed by micro contact printing of laminin. The slice cultures were evaluated by means of phase contrast microscopy at 3-22 days in culture. We were able to consistently achieve outgrowth of neurons, neurites and filopodia from brain stem slices cultured on ECM proteins structures of grid- and line-shapes. We believe that brain slice cultures on patterned substrates is a favourable approach to study functional synapses in vitro under defined conditions. The use of appropriate structures and the subsequent cell patterning may help to gain further understanding of axonal, dendritic and synaptic signal transductions and processes.

Quantification of regional intrapulmonary oxygen partial pressure evolution during apnea by (3)He MRI

We present a new method to determine in vivo the temporal evolution of intrapulmonary oxygen concentrations by functional lung imaging with hyperpolarized (3)Helium ((3)He-->). Single-breath, single-bolus visualization of (3)He--> administered to the airspaces is used to analyze nuclear spin relaxation caused by the local oxygen partial pressure p(O(2))(t). We model the dynamics of hyperpolarization in the lung by rate equations. Based hereupon, a double acquisition technique is presented to separate depolarization by RF pulses and oxygen induced relaxation. It permits the determination of p(O(2)) with a high accuracy of up to 3% with simultaneous flip angle calibration using no additional input parameters. The time course of p(O(2)) during short periods of breathholding is found to be linear in a pig as well as in a human volunteer. We also measured the wall relaxation time in the lung and deduced a lower limit of 4.3 min.

The immunomodulatory effect on BM 12.531 (azimexon) on normal or tumored mice: in vitro and in vivo studies

The effect of BM 12.531 (BM) treatment on normal or tumored mice was studied under both in vitro and in vivo experimental conditions. It was found that BM treatment of mice that received 500 R of whole body irradiation caused a highly significant (P < 0.001) increase in the prolongation of the mean survival time. BM was found to significantly increase (P < 0.01) the delayed-type hypersensitivity reaction of normal mice. BM treatment was found to moderately increase both in vivo and in vitro activated macrophages. However, BM was found to be extremely effective in significantly increasing the mean survival times of lung carcinoma-bearing or leukemic mice.