PAX genes and human neural tube defects: an amino acid substitution in PAX1 in a patient with spina bifida

From studies in the mouse and from the clinical and molecular analysis of patients with type 1 Waardenburg syndrome, particular members of the PAX gene family are suspected factors in the aetiology of human neural tube defects (NTD). To investigate the role of PAX1, PAX3, PAX7, and PAX9, allelic association studies were performed in 79 sporadic and 38 familial NTD patients from the Dutch population. Sequence variation was studied by SSC analysis of the paired domain regions of the PAX1, PAX7, and PAX9 genes and of the complete PAX3 gene. In one patient with spina bifida, a mutation in the PAX1 gene was detected changing the conserved amino acid Gln to His at position 42 in the paired domain of the protein. The mutation was inherited through the maternal line from the unaffected grandmother and was not detected in 300 controls. In the PAX3 gene, variation was detected at several sites including a Thr/Lys amino acid substitution in exon 6. All alleles were present among patients and controls in about the same frequencies. However, an increased frequency of the rare allele of a silent polymorphism in exon 2 was found in NTD patients, but no significant association was observed (p = 0.06). No sequence variation was observed in the paired domain of the PAX7 and PAX9 genes. Our findings so far do not support a major role of the PAX genes examined in the aetiology of NTD. However, the detection of a mutation in PAX1 suggests that, in principle, this gene can act as a risk factor for human NTD.     

Fibromuscular dysplasia associated with intracranial giant aneurysm: report of a case

Although the correlation between fibromuscular dysplasia (FMD) and intracranial aneurysm is well established, the combination of FMD with a giant aneurysm is rare. This paper reports a patient with extracranial FMD associated with a giant intracavernous aneurysm compromising the trigeminal and abducens nerve. A review of the literature uncovered only four documented cases of FMD with concurrent giant intracranial aneurysms. The present case adds further weight to the argument for including FMD in the differential diagnosis list when confronted with a patient with a giant intracranial aneurysm. Absence of adequate collaterals in this patient eliminated ligation as a treatment strategy for the aneurysm.     

Two-step hybrid virtual array ray (VAR) technique for focusing through the rib cage

A new methodology for focusing ultrasonic beams noninvasively in the presence of the rib cage is investigated. This investigation is motivated by the need to employ high intensity focused ultrasound (HIFU) using phased array applicators for the treatment of liver tumors partially shadowed by the rib obstacles. This approach enables us to efficiently perform the ultrasound computational analysis and pattern synthesis in the interior region of the rib cage. The proposed technique consists of two main steps. First, a virtual array is introduced along the intercostal spacings between the solid ribs to generate the prespecified intensity levels at a set of control points within the target region. The second step involves the design of the actual feed array that induces the virtual sources between the intercostal spacings. This design optimization is carried out via the pseudo-inverse technique (minimum norm least squares solution) and by enforcing a constrained preconditioned pseudo-inverse method. The proposed procedure calculates the required primary sources (feed array) while maintaining minimal power deposition over the solid obstacles.     

CERAMICS AS CANDIDATE STRUCTURAL MATERIALS FOR CRYOGENIC APPLICATIONS

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Homogeneous Styrene Butadiene/Acrylonitrile Butadiene Rubber Blends

The graft copolymerization of acrylonitrile (AN) onto butadiene rubber (BR) was carried out in toluene at 80°C, using dibenzoyl-peroxide (BPO) as initiator. The synthesized poly acrylonitrile-grafted-butadiene rubber (AN-g-BR) was characterized by N% elemental analysis and Fourier-transform infrared (FT-IR) spectroscopy. Styrene butadiene rubber/acrylonitrile butadiene rubber (SBR/NBR) blends were prepared with different blend ratios in presence and absence of AN-g-BR, where the homogeneity of such blends were examined with intrinsic viscosity (η) measurements, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). The scanning electron micrographs illustrate disappearance of the macro-scale phase separation of SBR/NBR rubber blend as a result of the incorporation of AN-g-BR into that blend. Viscosity measurements confirm homogeneity of that blend. Differential Scanning Calorimetry traces exhibit shifts in glass transition temperatures (T _g's) of SBR and NBR in their blend, indicating some degree of homogeneity. Physico-mechanical properties of the rubber blend vulcanizates with different blend ratios, in presence and absence of AN-g-BR, were investigated before and after accelerated thermal aging. The SBR/NBR (25/75) homogeneous blend possessed the best physico-mechanical properties after thermal aging, together with the best swelling behavior in motor oil. The physico-mechanical properties of SBR/NBR (25/75) filled blend with different types of inorganic fillers during thermal aging were studied.     

p53 codon 72 polymorphism in Taiwanese lung cancer patients: association with lung cancer susceptibility and prognosis

Previous studies have indicated that milrinone, a specific type III phosphodiesterase inhibitor, may be able to induce chloride secretion in cystic fibrosis (CF) tissues. We have now assessed the effect of this agent in vivo on the nasal epithelium of CF mutant mice and also in the nose and lungs of human subjects with CF. Wild-type mice showed a small hyperpolarization of the nasal potential difference (PD) in response to milrinone (100 microM, 1.6 +/- 0.6 mV, n = 8, P < 0.05). In contrast, CF mice carrying either the most common human mutation of the gene for the CF transmembrane regulator (CFTR), DeltaF508 (protein mislocalized), or the G551D mutation (protein normally localized) failed to demonstrate this response. Milrinone perfused alone had no significant effect on the baseline nasal PD of human subjects without CF (14.7 +/- 4.0 mV preperfusion; 15.3 +/- 4.6 mV postperfusion), but significantly (P < 0.05) augmented the hyperpolarization induced by a subsequently perfused low-chloride solution (with milrinone, 36.8 +/- 3.0 mV, n = 6; without milrinone, 18.1 +/- 2.2 mV, n = 19). In contrast, in human subjects with CF (n = 6), milrinone alone significantly (P < 0. 05) altered the nasal baseline PD (52.2 +/- 3.3 mV preperfusion; 57. 4 +/- 4.2 mV, postperfusion) but not the subsequent responses to the low-chloride solution (with milrinone, 1.1 +/- 2.2 mV, n = 4; without milrinone, 0.6 +/- 0.5 mV, n = 28) or to isoproterenol (100 microM). In a separate study in subjects (n = 6) with the DeltaF508 mutation, nasal coadministration of milrinone with isoproterenol produced no effect in the presence of amiloride and a low-chloride solution (-0.8 +/- 0.5 mV). This was also the case in the nasal epithelium of CF subjects (n = 4) carrying at least one G551D allele (-0.3 +/- 0.8 mV). Similarly, milrinone did not hyperpolarize the PD of either the tracheal (n = 6) or segmental (n = 6) airways of CF subjects (DeltaF508) when applied topically in vivo in the presence of amiloride, isoproterenol, or adenosine triphosphate (all 100 microM) in a low-chloride solution. These data do not support the use of milrinone to induce chloride secretion in CF airways in vivo.