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In JoVE (1)
Other Publications (4)
Articles by Nita Sahani in JoVE
JoVE General
In vivo Micro-circulation Measurement in Skeletal Muscle by Intra-vital Microscopy
1Department of Anesthesiology and Critical Care, Shriners Hospital for Children, Massachusetts General Hospital, and Harvard Medical School, 2Department of Geriatric Medicine, Graduate School of Medicine, The University of Tokyo
A new versatile method for observation of microcirculation is presented. It is considered suitable for long-term observation, and for combination with pharmacophysiological or molecular biological interventions.
Other articles by Nita Sahani on PubMed
Adipocyte Apoptosis After Burn Injury is Associated with Altered Fat Metabolism
Burn injury often is associated with the abnormal lipid metabolism, including hyperlipidemia, desensitization to lipolytic responses to catecholamines, and reduction in the size of the white adipose tissue. Understanding the biological mechanisms for the decrease in fat mass despite desensitization to catecholamines is important both for the study of lipid metabolism and for the study of its relationship to concomitant insulin resistance. Using epididymal adipose tissue from adult male Sprague-Dawley rats after burn injury (n = 102) or sham-burn injury (n = 102), we tested the hypothesis that a whole-body burn injury causes apoptosis in that tissue. At 1, 3, and 7 days after 40% to 50% body burn injury to the rat, epidydimal adipose tissue was harvested and studied for apoptotic changes and lipolytic properties. For apoptosis, paraformaldehyde-fixed tissue sections were analyzed by in situ TdT-mediated dUTP-X nick-end labeling (TUNEL) staining, and tissue homogenates were also analyzed for DNA fragmentation by enzyme-linked immunoassay and ligation-mediated polymerase chain reaction ladder assay. Isolated adipocytes were stimulated with isoprotenerol, and glycerol production was measured as a reflector of effectiveness of lipolysis. Epididymal adipose tissue showed increased apoptosis manifested by the positive TUNEL staining and increased DNA fragmentation by enzyme-linked immunoassay at day 3 and 7 after burn injury. The DNA fragmentation was confirmed further by the ligation-mediated polymerase chain reaction ladder assay. This elevated DNA fragmentation persisted in the burned animals from day 3 until day 7 after burn injury, the end of observation period. Increase in apoptosis was correlated with decrease in DNA content and tissue weight in the epidydimis. At the functional level, a significant decrease in isoproterenol-induced lipolytic activity (glycerol production) was observed to almost 50% of control level at day 3 and 7 but was not decreased at day 1. Apoptosis of adipocytes may play a role in the altered lipid metabolism, including hyperlipidemia observed in burned subjects.
Long-term Effects of Botulinum Toxin on Neuromuscular Function
Recent reports indicate increased incidence of Clostridium botulinum infections, particularly among drug abusers and tissue allograft recipients. Botulinum toxin also has potential application in biochemical warfare. The neurotoxin-induced paralysis often requires mechanical ventilation with and without muscle relaxants. The authors investigated the long-term effects of botulinum toxin on muscle function, expression of nicotinic acetylcholine receptors (nAChRs), and their interaction with muscle relaxant, atracurium.
Mitochondria, Endoplasmic Reticulum, and Alternative Pathways of Cell Death in Critical Illness
Dying cells are distinguished by their biochemical and morphologic traits and categorized into three subtypes: apoptosis, oncosis (necrosis), and cell death with autophagy. Each of these types of cell death plays critical roles in tissue morphogenesis during normal development and in the pathogenesis of human diseases. Given that tissue homeostasis is controlled by the intricate balance between degeneration and regeneration, it is essential to understand the mechanisms of different forms of cell death to establish and improve therapeutic interventions for prevention and rescue of these cell death-related disorders. Critical illness, including sepsis, trauma, and burn injury, is often complicated by multiple organ dysfunction syndrome and is accompanied by increased cell death in parenchymal and nonparenchymal tissues. Accumulating evidence suggests that augmented cell death plays an important role in the organ failure in critical illness. We discuss possible therapeutic approaches for prevention of cell death, particularly apoptotic cell death.
Primary Role of Functional Ischemia, Quantitative Evidence for the Two-hit Mechanism, and Phosphodiesterase-5 Inhibitor Therapy in Mouse Muscular Dystrophy
Duchenne Muscular Dystrophy (DMD) is characterized by increased muscle damage and an abnormal blood flow after muscle contraction: the state of functional ischemia. Until now, however, the cause-effect relationship between the pathogenesis of DMD and functional ischemia was unclear. We examined (i) whether functional ischemia is necessary to cause contraction-induced myofiber damage and (ii) whether functional ischemia alone is sufficient to induce the damage.
