			Home About us Contact

Vacuole Formation (vacuole + formation)

Distribution by Scientific Domains

Medical Sciences	60%
Life Sciences	40%

Selected Abstracts

Megalencephalic leukoencephalopathy with subcortical cysts: an update and extended mutation analysis of MLC1,

HUMAN MUTATION, Issue 6 2006
P. K. Ilja Boor
Abstract Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is an autosomal recessive cerebral white matter disorder in children. This disease is histopathologically characterized by myelin splitting and intramyelinic vacuole formation. MLC is caused by mutations in the gene MLC1, which encodes a novel protein, MLC1. Since the first report, 50 mutations in this gene have been found. Mutations occur throughout the entire coding region and include all different types: 11 splice-site mutations; one nonsense mutation; 24 missense mutations; and 14 deletions and insertions. Until now, six polymorphisms within the coding sequence of MLC1 had been reported. In about 20% of the patients with a typical clinical and MRI picture, no mutations in the MLC1 gene are found. Several of the families, in which no mutations are found, also do not show linkage with the MLC1 locus, which suggests a second gene involved in MLC. The absence of mutations may also be the consequence of performing standard mutation analysis that can miss heterozygous deletions, mutations in the promoter, 3, and 5, untranslated regions (UTRs), and intron mutations, which may influence the amino acid composition of the end product. In this work we describe 13 novel mutations, including those found with extended mutation analysis on MLC patients. This study shows that extended mutation analysis is a valuable tool to identify at least some of the missing mutations. Therefore, we suggest extended mutation analysis for the MLC1 gene, if no mutations are found during standard analysis. Hum Mutat 27(6), 505,512, 2006. © 2006 Wiley-Liss, Inc. [source]

An Integrin and Rho GTPase-Dependent Pinocytic Vacuole Mechanism Controls Capillary Lumen Formation in Collagen and Fibrin Matrices

MICROCIRCULATION, Issue 1 2003
GEORGE E. DAVIS
ABSTRACT A major question that remains unanswered concerning endothelial cell (EC) morphogenesis is how lumens are formed in three-dimensional extracellular matrices (ECMs). Studies from many laboratories have revealed a critical role for an ECM-integrin-cytoskeletal signaling axis during EC morphogenesis. We have discovered a mechanism involving intracellular vacuole formation and coalescence that is required for lumen formation in several in vitro models of morphogenesis. In addition, a series of studies have observed vacuoles in vivo during angiogenic events. These vacuoles form through an integrin-dependent pinocytic mechanism in either collagen or fibrin matrices. In addition, we have shown that the Cdc42 and Rac1 guanosine triphosphatases (GTPases), which control actin and microtubule cytoskeletal networks, are required for vacuole and lumen formation. These GTPases are also known to regulate integrin signaling and are activated after integrin-matrix interactions. Furthermore, the expression of green fluorescent protein-Rac1 or -Cdc42 chimeric proteins in ECs results in the targeting of these fusion proteins to intracellular vacuole membranes during lumen formation. Thus, a matrix-integrin-cytoskeletal signaling axis involving both the Cdc42 and Rac1 GTPases regulates the process of EC lumen formation in three-dimensional collagen or fibrin matrices. [source]

Vibration Causes Acute Vascular Injury in a Two-Step Process: Vasoconstriction and Vacuole Disruption

THE ANATOMICAL RECORD : ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY, Issue 8 2008
Sandya R. Govindaraju
Abstract Hand,arm vibration syndrome is a vasospastic and neurodegenerative occupational disease. In the current study, the mechanism of vibration-induced vascular smooth muscle cell (SMC) injury was examined in a rat-tail vibration model. Tails of male Sprague Dawley rats were vibrated continuously for 4 hr at 60 Hz, 49 m/s2 with or without general anesthesia. Ventral tail arteries were aldehyde fixed and embedded in epoxy resin to enable morphological analysis. Vibration without anesthesia caused vasoconstriction and vacuoles in the SMC. Anesthetizing rats during vibration prevented vasoconstriction and vacuole formation. Exposing tail arteries in situ to 1 mM norepinephrine (NE) for 15 min induced the greatest vasoconstriction and vacuolation. NE induced vacuoles were twice as large as those formed during vibration. When vibrated 4 hr under anesthesia after pretreatment with NE for 15 min, the SMC lacked vacuoles and exhibited a longitudinal banding pattern of dark and light staining. The extracellular matrix was filled with particulates, which were confirmed by electron microscopy to be cellular debris. The present findings demonstrate that vibration-induced vasoconstriction (SMC contraction) requires functioning central nervous system reflexes, and the physical stress of vibration damages the contracted SMC by dislodging and fragmenting SMC vacuoles. Anat Rec, 291:999,1006, 2008. © 2008 Wiley-Liss, Inc. [source]

Six novel mutations of the ADAR1 gene in patients with dyschromatosis symmetrica hereditaria: Histological observation and comparison of genotypes and clinical phenotypes

THE JOURNAL OF DERMATOLOGY, Issue 7 2008
Taisuke KONDO
ABSTRACT Dyschromatosis symmetrica hereditaria (DSH), is a pigmentary genodermatosis of autosomal dominant inheritance. Since we clarified that the disease is caused by a mutation of the adenosine deaminase acting on the RNA 1 gene (ADAR1) in 2003, the molecular pathogenesis of a peculiar clinical feature of the disease has been expected to be clarified. We examined five familial cases and one sporadic case of Japanese families with DSH. The mutation analyses were done with single-strand conformation polymorphism/heteroduplex (SSCP/HD) analysis and direct sequencing of ADAR1. The DNA analysis of each patient revealed one missense mutation (p.F1091S), two nonsense mutations (p.C893X, p.S581X) and three frame-shift mutations (p.E498fsX517, p.F1091fsX1092, p.L855fsX856). Visual and electron microscopic findings showed abundant melanin pigment deposited all over the basal layer, and enlarged melanocytes with long dendrites located in the pigmented lesions with small or immature melanosomes scattered sparsely in the cytoplasm, but in the adjacent keratinocytes many small melanosomes were singly dispersed or aggregated. The hypopigmented areas showed little melanin deposition and reduced numbers of melanocytes in which much degenerative cytoplasmic vacuole formation could be observed by electron microscopy. Herein, we report six cases of DSH with six novel mutations. The variety of their clinical phenotypes even in the pedigree may suggest the presence of factors other than the ADAR1 gene influencing the extent of the clinical skin lesion. Microscopic findings suggest that the clinical appearance must have developed directly by melanocyte variations mainly induced by the ADAR1 gene mutations. [source]

Morphological and morphometric attributes of epididymal and testicular spermatozoa following surgical sperm retrieval for obstructive and nonobstructive azoospermia

ANDROLOGIA, Issue 6 2003
Dr. S. Wood
Summary. Whilst the morphological (shape) and morphometric (sperm head size) attributes of ejaculated spermatozoa have been well studied, the morphological and morphometric qualities of testicular and epididymal spermatozoa retrieved from males with obstructive and nonobstructive azoospermia is much less documented. We wished to examine the effect of aetiology of azoospermia and site of retrieval on the attributes of retrieved spermatozoa. This was a prospective observational study of 30 consecutive successful sperm retrievals, six for nonobstructive azoospermia and 24 for obstructive, of which five were retrieved from the epididymis and the remainder from the testis. The proportion of morphologically normal testicular spermatozoa in patients with obstructive and nonobstructive azoospermia was not significantly different (7% versus 7.6%, P = 0.97). Testicular spermatozoa from males with obstructive azoospermia showed an increase in frequency of sperm with small heads [47/180 (26%) versus 97/909 (11%), P = 0.036] as well as small acrosome and increasing vacuole formation over nonobstructive spermatozoa. Similarly, there was a significant increase in tail deformities and decreases in tail lengths in sperm from males with nonobstructive azoospermia. Epididymal spermatozoa showed significantly greater proportion of morphologically normal spermatozoa than testicular (20% versus 13%, P = 0.001) as well as a significant increase in acrosome vacuoles. Furthermore, morphometrically epididymal spermatozoa displayed with smaller head length, width and area than testicular spermatozoa. Testicular spermatozoa from obstructive azoospermia displayed significantly less tail defects (35% versus 57%, P = 0.003) as well as significantly longer tail lengths (30.6 ,m versus 10.7 ,m). These morphological and morphometric differences between epididymal and testicular and obstructive and nonobstructive spermatozoa may represent part of the natural maturation process. There were no associations between any morphological or morphometric abnormality with any significant parameter in subsequent use in ICSI. [source]