Southern Illinois University School of Medicine

About: Southern Illinois University School of Medicine is a education organization based out in Springfield, Illinois, United States. It is known for research contribution in the topics: Population & Cancer. The organization has 3747 authors who have published 5977 publications receiving 209115 citations. The organization is also known as: SIU School of Medicine.

Life extension in the dwarf mouse.

Abstract: Ames dwarf mice and Snell dwarf mice lack growth hormone (GH), prolactin (PRL), and thyroid-stimulating hormone (TSH), live much longer than their normal siblings, and exhibit many symptoms of delayed aging. “Laron dwarf mice,” produced by targeted disruption of the GH receptor⧸GH-binding protein gene (GHR-KO mice), are GH resistant and also live much longer than normal animals from the same line. Isolated GH deficiency in “little” mice is similarly associated with increased life span, provided that obesity is prevented by reducing fat content in the diet. Long-lived dwarf mice share many phenotypic characteristics with genetically normal (wild-type) animals subjected to prolonged caloric restriction (CR) but are not CR mimetics. We propose that mechanisms linking GH deficiency and GH resistance with delayed aging include reduced hepatic synthesis of insulin-like growth factor 1 (IGF-1), reduced secretion of insulin, increased hepatic sensitivity to insulin actions, reduced plasma glucose, reduced generation of reactive oxygen species, improved antioxidant defenses, increased resistance to oxidative stress, and reduced oxidative damage. The possible role of hypothyroidism, reduced body temperature, reduced adult body size, delayed puberty, and reduced fecundity in producing the long-lived phenotype of dwarf mice remains to be evaluated. An important role of IGF-1 and insulin in the control of mammalian longevity is consistent with the well-documented actions of homologous signaling pathways in invertebrates.

Gap detection deficits in rats with tinnitus: A potential novel screening tool.

Abstract: The study describes a novel method for tinnitus screening in rats by use of gap detection reflex procedures. The authors hypothesized that if a background acoustic signal was qualitatively similar to the rat's tinnitus, poorer detection of a silent gap in the background would be expected. Rats with prior evidence of tinnitus at 10 kHz (n = 14) exhibited significantly worse gap detection than controls (n = 13) when the gap was embedded in a background similar to their tinnitus. No differences between tinnitus and control rats were found with 16 kHz or broadband noise backgrounds, which helped to rule out explanations related to hearing loss or general performance deficits. The results suggest that gap detection reflex procedures might be effective for rapid tinnitus screening in rats.

Morphologic Analysis of the Microcirculation During Reperfusion of Ischemic Skeletal Muscle and the Effect of Hyperbaric Oxygen

Abstract: The morphologic events in the microcirculation that lead to reperfusion injury of ischemic skeletal muscle remain incompletely understood. The purpose of this experiment was to evaluate leukocyte endothelial adherence characteristics and dynamic changes in microvessel caliber during reperfusion of an in vivo skeletal muscle ischemia preparation. In addition, the effect of hyperbaric oxygen treatment on these microcirculatory changes also was studied. An intravital microscopy preparation of a transilluminated gracilis muscle in 27 rats was used to observe a total of 101 arterioles and 63 venules (13 to 73 microns diameter). Baseline hemodynamics were videotaped for 30 minutes following muscle isolation. The animals were divided into six groups: (1) sham, no ischemia, (2) 4 hours of global ischemia only, (3) no ischemia plus hyperbaric oxygen (one 2.5 ATA/1 hour of treatment with 100% oxygen), (4) 4 hours of ischemia plus hyperbaric oxygen during ischemia, (5) 4 hours of ischemia plus hyperbaric oxygen immediately on reperfusion, and (6) 4 hours of ischemia plus hyperbaric oxygen 1 hour after reperfusion. Changes in arteriolar and venular diameters at specific times during 3 hours of reperfusion were recorded, and the number of adherent and slow-rolling leukocytes in 100-microns venular segments were counted and compared with baseline measurements. The proximity of arterioles to venules was classified as adjacent ( 15 microns). No significant changes in leukocyte endothelial adherence or arteriolar diameter were noted in group 1 sham or group 3 nonischemic hyperbaric oxygen-treated rats when compared with baseline measurements. A significant increase in adherent leukocytes was observed in group 2 ischemic venules (+14.9 +/- 2.5) within 5 minutes of reperfusion, which was maintained for 3 hours. Reperfusion measurements of arteriolar diameter in group 2 ischemic muscle preparations demonstrated an initial vasodilation that was followed at 1 hour by a progressive and severe vasoconstriction (-46.9 +/- 11.3 percent at 3 hours) in arterioles adjacent to venules that was not seen in distant arterioles. The increase in adherent leukocytes seen in group 2 ischemic venules was significantly reduced by hyperbaric oxygen treatment given during ischemia (group 4) or up to 1 hour during reperfusion (groups 5 and 6). In addition, the progressive ischemic arteriolar vasoconstriction was inhibited in all groups (4, 5, and 6) treated with hyperbaric oxygen.(ABSTRACT TRUNCATED AT 400 WORDS)

Treatment of patients with essential tremor

Abstract: Essential tremor is a common movement disorder. Tremor severity and handicap vary widely, but most patients with essential tremor do not receive a diagnosis and hence are never treated. Furthermore, many patients abandon treatment because of side-effects or poor efficacy. A newly developed algorithm, based on the logarithmic relation between tremor amplitude and clinical tremor ratings, can be used to compare the magnitude of effect of available treatments. Drugs with established efficacy (propranolol and primidone) produce a mean tremor reduction of about 50%. Deep brain stimulation (DBS) in the thalamic nucleus ventrointermedius or neighbouring subthalamic structures reduces tremor by about 90%. However, no controlled trials of DBS have been done, and the best target is still uncertain. Better drugs are needed, and controlled trials are required to determine the safety and efficacy of DBS in the nucleus ventrointermedius and neighbouring subthalamic structures.

Cyclooxygenases, prostanoids, and tumor progression.

Abstract: In response to various growth factors, hormones or cytokines, arachidonic acid can be mobilized from phospholipids pools and converted to bioactive eicosanoids through cyclooxygenase (COX), lipoxygenase (LOX) or P-450 epoxygenase pathway. The COX pathway generates five major prostanoids (prostaglandin D(2), prostaglandin E(2), prostaglandin F(2)alpha, prostaglandin I(2) and thromboxane A(2)) that play important roles in diverse biological processes. Studies suggest that different prostanoids and their own synthase can play distinct roles in tumor progression and cancer metastasis. COX-2 and PGE(2) synthase have been most well documented in the regulation of various aspects of tumor progression and metastasis. PGE(2), for example, can stimulate angiogenesis or other signaling pathways by binding to its receptors termed EPs. Therefore, targeting downstream prostanoids may provide a new avenue to impede tumor progression. In this review, aberrant expression and functions of several prostanoid synthetic enzymes in cancer will be discussed. The possible regulation of tumor progression by prostaglandins and their receptors will also be discussed.