PubMed · 6827640
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J Vela, J Harris, J K Wright, R A Hardin, R B Terry, R Aquino. 1983. Self-mutilation.. https://doi.org/10.1097/00005373-198302000-00020
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Neurons and glia are produced in stereotyped patterns after neuroblast cell division during development of the Drosophila central nervous system. The first cell division of thoracic neuroblast 6-4 (NB6-4T) is asymmetric, giving rise to a glial precursor cell and a neuronal precursor cell. In contrast, abdominal NB6-4 (NB6-4A) divides symmetrically to produce two glial cells. To understand the relationship between cell division and glia-neuron cell fate determination, we examined and compared the effects of known cell division mutations on the NB6-4T and NB6-4A lineages. Based on observation of expression of glial fate determination and early glial differentiation genes, the onset of glial differentiation occurred in NB6-4A but not in NB6-4T when both cell cycle progression and cytokinesis were genetically arrested. On the other hand, glial differentiation started in both lineages when cytokinesis was blocked with intact cell cycle progression. These results showed that NB6-4T, but not NB6-4A, requires cell cycle progression for acquisition of glial fate, suggesting that distinct mechanisms trigger glial differentiation in the different lineages.
INTRODUCTION: In previous studies we described mechanisms by which acute elevation of the intraabdominal pressure (IAP) induces intracranial hypertension (ICHTN). Here we sought to define the role of ICHTN in mediating systemic hypertension (HTN) during CO(2) pneumoperitoneum (PNP). METHODS: Six large animals (swine) were hyperventilated to buffer hypercarbia. Intracranial pressure (ICP) was monitored with a Camino intraparenchymal ICP monitoring system. A Foley catheter was introduced intracranially via a separate burr hole. At phase 1, changes in ICP, central venous pressure (CVP), and mean arterial pressure (MAP) were recorded during periods of CO(2) PNP at IAP levels of 15, 20, 25, and 30 mm Hg. At phase 2, ICHTN was produced directly by inflating the intracranial balloon to the same ICP levels that had been measured in phase 1 for each degree of IAP. CVP and MAP were recorded. Repeated measures analysis of variance was applied. RESULTS: At phase 1, the mean DeltaCVP, DeltaICP, and DeltaMAP increased relative to the degree of IAP (P = 0.0001, 0.0004, and 0.024, respectively). At phase 2, the increments in DeltaMAP were significant (P = 0.024) and in the same direction and amplitude as at phase 1. CONCLUSIONS: In this study, increasing the IAP with CO(2) PNP with a consequent increase of ICP and direct manipulation of the ICP produced a comparable systemic HTN. We believe that this further supports our hypothesis: Elevated IAP produces an immediate increase in the CVP, which impairs venous drainage from the central nervous system (CNS), increases the ICP, and initiates a CNS-mediated response and systemic HTN.
A 4-year-old Holstein cow from a farm where 2 cows had recently died suddenly was referred for evaluation of acute severe colic. Right flank laparotomy revealed a large mesenteric hematoma. Within 14 layer chromatographic analyses of the moldy hay and blood from the necropsied cow and the hospitalized cow were positive for dicumarol. A diagnosis of sweet vernal poisoning was confirmed on the basis of clinical and toxicologic findings. The cow was treated with supportive therapy, blood transfusions, and vitamin K1 and recovered without complications. Because sweet vernal grass is becoming common in certain areas and the use of round bales is commonplace, practitioners should be aware of the potential for this toxicosis.