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Marginal Portion (marginal + portion)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Ectopic dermal ridge configurations on the interdigital webbings and postaxial marginal portion of the hindlimb in Hammertoe mutant mice (Hm),

JOURNAL OF MORPHOLOGY, Issue 10 2008
Sumiko Kimura
Abstract The effects of the hereditary malformation of Hammertoe mutant mice (gene symbol Hm) on the digital pads and dermal ridge configurations on their hindlimbs were examined. In the wild-type (+/+) mice with normally separated digits, dermal ridges developed only on the pads. Heterozygous (Hm/+) and homozygous (Hm/Hm) mutant mice, however, had a broad big toe, fused interdigital soft tissues, reduced claws, an extra rudimentary postaxial digit and camptodactyly. The dermal ridges appeared not only on the pads, affected in their number and configurations, but also on the ventral surface of the interdigital webbings and postaxial marginal area exhibiting an extra rudimentary digit and webbing. These aberrant configurations may be related to the abnormal occurrence of programmed cell death (PCD) in the interdigital zones and the postaxial marginal portion in Hm/+ and Hm/Hm mice. That is, the diminished cell death may fail to decrease the cell density in the interdigital zones and postaxial marginal portion and result in the webbing and an extra rudimentary digit and webbing, respectively. Simultaneously, it could also interrupt the migration of surviving cells of these areas toward the neighboring digits and the distal area of the sole and produce the ectopic dermal ridges on the way to the as yet unformed (presumptive) digital and plantar volar pads. The present findings suggest that normal interdigital and pre/postaxial PCD contributes not only to the separation of digits, the initial formation of individual digits of different sizes, and the inhibition of the extra digit but also to the development of the presumptive digital and plantar pads, including dermal ridges. J. Morphol., 2008. © 2008 Wiley-Liss, Inc. [source]

Multinucleated astrocytes in old demyelinated plaques in a patient with multiple sclerosis

NEUROPATHOLOGY, Issue 3 2004
Makoto Nishie
A 51-year-old woman with MS of 26 years duration is reported. The patient's MS history began at the age of 25 years with an initial relapsing-remitting course, followed by slow progression without distinct relapses. She became bed-ridden at the age of 40 years. A post-mortem examination revealed numerous demyelinated plaques that exhibited fibrillary gliosis with Rosenthal fibers, but without lymphocytic cuffing or foamy macrophages. Activated microglia were found mainly in the marginal portion of the plaques. These plaques were consistent with so-called ,slowly expanding plaques'. Interestingly, multinucleated astrocytes were observed within the plaques, being more numerous in the area where microglial infiltration had occurred. These findings suggest that mild persistent inflammatory processes are present even in old plaques and that certain inflammatory stimuli cause multinucleation of astrocytes. This might explain the gradual deterioration without definite relapses observed in the late stage of MS. [source]

Levator palpebrae superioris muscle in human fetuses: Anatomical findings and their clinical relevance

CLINICAL ANATOMY, Issue 7 2005
J. Plock
Abstract Accessory medial muscular bellies of the levator palpebrae superioris muscle and broad lateral insertion of its aponeurosis into tissue near the lacrimal gland have been reported as rare variations in adults. The anatomy of this muscle was studied in orbits of ten human fetuses between the 5th and 10th months of gestation. In each of the dissected orbits, the levator palpebrae superioris muscle had a broad lateral insertion into the capsule of the lacrimal gland or the periorbita, in this period of development. In addition, medial accessory muscles of the levator or singular muscle fibers within fibrous bands that inserted near the trochlear region and the medial portion of the upper eyelid were present in 70% of the fetuses, either unilaterally or bilaterally. These findings demonstrate new unreported aspects of levator palpebrae superioris development and morphology. Our findings suggest that an initial broad anterior primary anlage of the muscle is followed by secondary atrophy of lesser used marginal portions of this muscle, which are replaced by delicate connective tissue. These findings might force new considerations about diagnostic and therapeutic approaches to congenital mobility disorders of the levator palpebrae superioris muscle, such as blepharoptosis or eyelid retraction. The clinical relevance of our results are discussed along with a review of the embryogenesis of extraocular muscles and soft tissue of the orbit. Clin. Anat. 18:473,480, 2005. © 2005 Wiley-Liss, Inc. [source]