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  • 1
    Electronic Resource
    Electronic Resource
    Developmental Pattern for Phosphatidylserine Decarboxylase in Rat Brain (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 46 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: In adult rats, a significant portion of brain ethanolamine glycerophospholipids are synthesized by a pathway involving phosphatidylserine decarboxylase, a mitochondrial enzyme. We have now examined whether this enzyme plays a particularly prominent role during development. Activities for both phosphatidylserine decarboxylase and succinate dehydrogenase (another mitochondrial enzyme) were determined in brain homogenates from rats 5 days of age to adulthood. Succinate dehydrogenase activity, expressed on a per unit brain protein basis, increased markedly during development. This pattern has been reported previously and is as expected from the postnatal increase in oxidative metabolism. In contrast, phosphatidylserine decarboxylase activity decreased 40% from 5 to 30 days of age. The apparent Km for brain phosphatidylserine decarboxylase was 85 μM in both young (8- and 20-day-old) and adult animals. Parallel studies in vivo were carried out to determine the contribution of the phosphatidylserine decarboxylase pathway, relative to pathways utilizing ethanolamine directly, to the synthesis of brain ethanolamine glycerophospholipids. Animals were injected intracranially with a mixture of L-[G-3H]serine and [2-14C]ethanolamine and incorporation into the base moieties of the phospholipids determined. The 3H/14C ratio of ethanolamine glycerophospholipids decreased about 50% during development. Our studies in vitro and in vivo both suggest that phosphatidylserine decarboxylase plays a significant role in the synthesis of brain ethanolamine glycerophospholipids at all ages, although it is relatively more prominent early in development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb00638.x
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  • 2
    Electronic Resource
    Electronic Resource
    Lipid Metabolism During Early Stages of Wallerian Degeneration in the Rat Sciatic Nerve (1989)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 52 (1989), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract We examined changes in biosynthetic capacity of sciatic nerve during the early stages of Wallerian degeneration, utilizing a model that permits exclusion of nonresident cells from degenerating nerve. Sciatic nerve segments were placed in either 5-μm pore (allowing infiltration of nonresident cells) or 0.22-μm pore (excluding nonresident cells) Millipore diffusion chambers and then implanted in the peritoneal cavity of the same 32-34-day-old rat. At times up to 7 days post-surgery, nerve segments from the chambers, as well as control segments from the contralateral sciatic nerve, were removed and their capacity to incorporate radioactive precursors into lipids and proteins assayed in vitro. In nerve segments from both the 0.22- and 5-μm pore chambers, incorporation of [14C]acetate into total lipids was decreased relative to control by 50% at 12 h postsurgery and by 85% at day 3. This decreased incorporation of [14C]acetate reflects primarily decreased de novo synthesis of cholesterol and of fatty acyl residues incorporated into glycerolipids and sphingolipids. There was a preferentially decreased synthesis of cerebrosides and cholesterol (components enriched in myelin) relative to other lipids, while cholesterol esters and free fatty acids (products of membrane degradation) accounted for a greater proportion of the greatly reduced levels of total lipid label. In contrast to [14C]acetate, incorporation of [3H]glycerol into lipids was increased up to fourfold, relative to control, 1 day after nerve transection. This increased incorporation of [3H]glycerol does not reflect de novo synthesis of lipids (which is decreased), but rather removal of toxic fatty acyl residues derived from degradation of myelin lipids; these toxic compounds must be removed by resynthesis into nonmyelin glycerolipids and cholesterol esters. The inhibition of de novo synthesis of myelin lipids in Schwann cells during the early stages of Wallerian degeneration occurs independently of hematogenously-derived cells. We suggest that Wallerian degeneration rapidly results in some breakdown of myelin, and that the increased free fatty acid levels resulting from degradation of myelin lipids inhibit the de novo synthesis of new myelin lipid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1989.tb01851.x
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  • 3
    Electronic Resource
    Electronic Resource
    Circumferential Distribution of Ganglion Cells in the Transition Zone of Children with Hirschsprung Disease (2000)
    Springer
    Pediatric and developmental pathology 3 (2000), S. 216-222 
    Details
    ISSN: 1615-5742
    Keywords: Key words: aganglionosis, ganglion cells, Hirschsprung disease, transition zone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We prospectively studied the circumferential distribution of ganglion cells in the transition zone from a study population of 21 patients with Hirschsprung disease (HD) undergoing a pull-through procedure over a 26-month period. Twelve cases were satisfactory for examination, in that the transition zone was contained within a single surgical specimen and specimen distortion was minimal. Ganglion cells in the submucosa were counted in all 12 cases. In seven of the cases, the transition zone was proximal to the rectal sleeve and myenteric plexus ganglion cells were also counted. We found an uneven circumferential distribution of ganglion cells in both myenteric plexus and submucosa of the transition zone, resulting in a “leading edge” of ganglion cells extending into aganglionic distal bowel. The maximum length of this leading edge was 2.4 cm and 2.1 cm in the myenteric plexus and submucosa, respectively. Ganglion cells at the tip of the leading edge were present in clusters of up to six ganglion cells, in marked contrast to an absence of ganglion cells for most of the remainder of the circumference. Closely spaced myenteric plexus ganglia were seen at the tip of the leading edge in some cases. The leading edge was more frequently observed along the antimesenteric side, but this was not statistically significant. Our findings have relevance in the interpretation of intraoperative biopsies at the time of pull-through surgery and subsequent biopsies of neorectum in patients with surgically corrected HD.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100249910028
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  • 4
    Electronic Resource
    Electronic Resource
    Bannayan-Riley-Ruvalcaba Syndrome: Spectrum of Intestinal Pathology Including Juvenile Polyps (2000)
    Springer
    Pediatric and developmental pathology 3 (2000), S. 155-161 
    Details
    ISSN: 1615-5742
    Keywords: Key words: Bannayan-Riley-Ruvalcaba syndrome, juvenile polyposis, ectopic ganglion cells, atypical polyps
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: ABSTRACT Bannayan-Riley-Ruvalcaba syndrome (BRRS) is a disorder that includes juvenile polyposis as part of its pathologic spectrum, and it recently has been shown to share phenotypic and genotypic features with Cowden's disease. In existing literature, descriptions of intestinal pathology in patients with BRRS are relatively sparse and occasionally erroneous. We describe the intestinal pathology in multiple specimens from three children with BRRS. Examination of gastrointestinal biopsies from these children revealed predominantly colonic and rectal polyps with the histology of juvenile polyps. Additionally, two cases with clusters of ectopic ganglion cells within the lamina propria, one in a colonic polyp and one in a duodenal biopsy, and an atypical polyp were observed. Bannayan-Riley-Ruvalcaba syndrome should be included in the list of differential diagnostic considerations when a child or young adult presents with a juvenile polyp, particularly if unusual histologic features such as atypical polyps or ectopic ganglion cells are encountered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100249910016
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