A pseudoisochromosome 18q and an isodicentric chromosome 18*

Floore, Cynthia; Robertson, A. S.; Samuel, Iris; Williamson, N.; McLeod, David; Hoganson, George; Hoo, J. J.

doi:10.1111/j.1399-0004.1989.tb02971.x

Cited by 9 publications

(6 citation statements)

References 6 publications

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“…This specimen is exceedingly rare, as a review of the literature indicates very few cases of chromosomal defects at Ch18 due to translocations or the described specific pseudo‐isodicentric chromosome 18 defect (Floore et al. ; Gravholt et al. ), and rarer still are cases involving both T18 and the presentation of cyclopia with HPE (Lang et al.…”

Section: Resultsmentioning

confidence: 99%

The human brain and face: mechanisms of cranial, neurological and facial development revealed through malformations of holoprosencephaly, cyclopia and aberrations in chromosome 18

et al. 2015

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The study of inborn genetic errors can lend insight into mechanisms of normal human development and congenital malformations. Here, we present the first detailed comparison of cranial and neuro pathology in two exceedingly rare human individuals with cyclopia and alobar holoprosencephaly (HPE) in the presence and absence of aberrant chromosome 18 (aCh18). The aCh18 fetus contained one normal Ch18 and one with a pseudo-isodicentric duplication of chromosome 18q and partial deletion of 18p from 18p11.31 where the HPE gene, TGIF, resides, to the p terminus. In addition to synophthalmia, the aCh18 cyclopic malformations included a failure of induction of most of the telencephalon – closely approximating anencephaly, unchecked development of brain stem structures, near absence of the sphenoid bone and a malformed neurocranium and viscerocranium that constitute the median face. Although there was complete erasure of the olfactory and superior nasal structures, rudiments of nasal structures derived from the maxillary bone were evident, but with absent pharyngeal structures. The second non-aCh18 cyclopic fetus was initially classified as a true Cyclops, as it appeared to have a proboscis and one median eye with a single iris, but further analysis revealed two eye globes as expected for synophthalmic cyclopia. Furthermore, the proboscis was associated with the medial ethmoid ridge, consistent with an incomplete induction of these nasal structures, even as the nasal septum and paranasal sinuses were apparently developed. An important conclusion of this study is that it is the brain that predicts the overall configuration of the face, due to its influence on the development of surrounding skeletal structures. The present data using a combination of macroscopic, computed tomography (CT) and magnetic resonance imaging (MRI) techniques provide an unparalleled analysis on the extent of the effects of median defects, and insight into normal development and patterning of the brain, face and their skeletal support.

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Section: Resultsmentioning

confidence: 99%

The human brain and face: mechanisms of cranial, neurological and facial development revealed through malformations of holoprosencephaly, cyclopia and aberrations in chromosome 18

et al. 2015

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“…In contrast to cases with a breakpoint in 18p, only few cases of an isopseudodicentric chromosome 18 with partial deletion of 18q have been published, and all these cases were mosaic. The clinical features are variable, depending on the respective breakpoints and the degree of mosaicism [Floore et al, 1989; Bryke et al, 1990; Fujiwara et al, 1992; Ausems et al, 1994].…”

Section: Introductionmentioning

confidence: 99%

Local application of tacrolimus in distal colitis: Feasible and safe

Dieren¹,

Bodegraven²,

Kuipers³

et al. 2009

Inflammatory Bowel Diseases

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“…Cytogenetically monocentric isochromosomes 18q are more common than dicentric. To our knowledge only 14 cases of cytogenetically dicentric isochromosomes 18 have been published [Laurent et al, 1978; Madan et al, 1981; Ward et al, 1981; Fioretti et al, 1982; Wulfsberg et al, 1984; Floore et al, 1989; Bryke et al, 1990; Fujiwara et al, 1992; Meguid and Habibian, 1992; Ausems et al, 1994; Brandt et al, 1994; Levy‐Mozziconacci et al, 1996; Gravholt et al, 1997]. In our cases 1 and 2, FISH analysis verified that they were monocentric as found by the cytogenetic analysis, and DNA analysis did not discover any short arm material in case 1.…”

Section: Discussionmentioning

confidence: 99%

“…The phenotype is in the majority of cases described as very similar to trisomy 18 or Edward's syndrome. Isochromosome 18q appears in the classical form with one centromere and two q arms and have been described in about 20 cases [Van Dyke, 1988 for review of cases before 1988; Chen et al, 1998 for review of cases after 1988], as double isochromosomes together with i(18p) described in four cases [Muller et al, 1972; Larson et al, 1978; Romain et al, 1992; van den Berg et al, 1999], and as a pseudodicentric chromosome with two centromeres separated by p arm material [Laurent et al, 1978; Madan et al, 1981; Ward et al, 1981; Fioretti et al, 1982; Wulfsberg et al, 1984; Meguid and Habibian, 1992; Brandt et al, 1994; Levy‐Mozziconacci et al, 1996; Gravholt et al, 1997] or q arm material [Floore et al, 1989; Bryke et al, 1990; Fujiwara et al, 1992; Ausems et al, 1994]. Isochromosomes are mirror duplications as they are composed of genetically identical arms.…”

Section: Introductionmentioning

confidence: 99%

Aramid‐short‐fiber reinforced rubber as a tire tread composite

Razzaghi‐Kashani

2009

J of Applied Polymer Sci

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in Wiley InterScience (www.interscience.wiley.com).ABSTRACT: Mechanical and dynamic-mechanical properties of a typical tire tread compound reinforced with one part aramid short fibers were investigated in order to predict the effects of fibers on tire tread performances such as rolling resistance and traction. Rubber processing, including mixing and extrusion, was performed in an industrial scale. Fiber orientation as a result of extrusion was evaluated quantitatively and qualitatively using mechanical anisotropy in swelling and scanning electron microscopy, respectively. Unidirectional tensile tests revealed higher modulus, but slightly lower strength and elongation at break for the composites stretched in the longitudinal (orientation) and transverse directions than those for the isotropic reference compound with no fiber. Dynamic mechanical thermal analysis showed that relative values of loss factor for the longitudinal and transverse composites and the reference compound depended on the state of polymer as glassy or rubbery. Therefore, a high loss factor at lower temperatures and a low loss factor at higher temperatures predicted a balanced improvement of tire traction and rolling resistance as a result of fiber addition. Heat build-up and abrasion experiments showed that addition of fiber did not deteriorate other performances of tire tread. Also, the fibers had negligible effects on processing and vulcanization characteristics of the composite.

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A pseudoisochromosome 18q and an isodicentric chromosome 18*

Cited by 9 publications

References 6 publications

The human brain and face: mechanisms of cranial, neurological and facial development revealed through malformations of holoprosencephaly, cyclopia and aberrations in chromosome 18

The human brain and face: mechanisms of cranial, neurological and facial development revealed through malformations of holoprosencephaly, cyclopia and aberrations in chromosome 18

Local application of tacrolimus in distal colitis: Feasible and safe

Aramid‐short‐fiber reinforced rubber as a tire tread composite

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