Search results for "Ultrastructure"
showing 4 items of 224 documents
Ultrastructural causes of rupture of hand tendons in patients with rheumatoid arthritis. A transmission and scanning electron microscopic study.
1993
To identify the cause of rupture of hand tendons in patients with rheumatoid arthritis, we studied the underlying ultrastructural changes of the collagenous fibril systems. Samples of the flexor digitorum superficialis (n = 12) and the extensor digitorum communis (n = 20) were taken during tenosynovectomy. Tendons dissected at necropsy (n = 30) served as controls. Specimens were analysed by transmission and scanning electron microscopy. Interfibrillar dysplastic fibrils, "Luse bodies", and intracellular collagen were found in rheumatoid tissues. The diameters of collagen fibrils were significantly reduced compared with the control group (p0.01). The duration of the disease usually correlate…
Ultrastructure of Dural Lesions Produced in Lumbar Punctures
2014
During lumbar puncture, the insertion of a single-use, short-beveled spinal needle produces a “tent-like” effect. The dura-arachnoid lesions produced by this Quincke type of needles show a “crescent moon” shape resembling the letter “U” or “V” (similar to the lid of a can), with clean-cut edges. As the needle tip advances, the cut fragment is folded inwards, while all dural and arachnoid layers are entirely severed and the edges of the lesion are displaced inwardly. As soon as the spinal needle is withdrawn, the edges of the lesion tend to retract, owing to the viscoelastic properties of the affected dura mater.
Age-Related Changes in Astrocytic and Ependymal Cells of the Subventricular Zone
2014
Neurogenesis persists in the adult subventricular zone (SVZ) of the mammalian brain. During aging, the SVZ neurogenic capacity undergoes a progressive decline, which is attributed to a decrease in the population of neural stem cells (NSCs). However, the behavior of the NSCs that remain in the aged brain is not fully understood. Here we performed a comparative ultrastructural study of the SVZ niche of 2-month-old and 24-month-old male C57BL/6 mice, focusing on the NSC population. Using thymidine-labeling, we showed that residual NSCs in the aged SVZ divide less frequently than those in young mice. We also provided evidence that ependymal cells are not newly generated during senescence, as ot…
Ultrastructure of posterior sternal glands of Macrotermes annandalei (Silvestri): new members of the sexual glandular set found in termites (Insecta)
2004
0362-2525 (Print) Comparative Study Journal Article; In female alates of Macrotermes annandalei, two types of abdominal glands are involved in the secretion of sex pheromone. Tergal glands are found at the anterior margin of tergites 6-10 and posterior sternal glands (PSGs) are located at the anterior margin of sternites 6-7. The cytological features of both types of glands are quite similar. The fine structural organization of PSGs is studied more precisely and described for the first time. The glandular cuticle is pitted with narrow apertures corresponding to the openings of numerous subcuticular pouches. Several Class 3 glandular units open in each pouch. One canal cell and one secretory…