Anabolic potential and regulation of the skeletal muscle satellite cell populations

PURPOSE OF REVIEW: Satellite cells are required for muscle regeneration to occur properly. An understanding of the mechanisms that increase their number is important for potential therapeutic use in a variety of muscle disorders. RECENT FINDINGS: This article reviews the state of knowledge regarding mechanisms and factors involved in regulating the satellite cell population. An overview of the soluble factors intrinsic to the regulation of the activation, proliferation and differentiation of satellite cells is presented. We also highlight our current knowledge of satellite cell specification that provides a potential basis for increasing satellite cell numbers by manipulating different cell types. Finally, summarizing our current knowledge of satellite cell self-renewal offers insight for possible avenues to increase the supply of satellite cells. SUMMARY: Multiple approaches for increasing the number and activity of satellite cells will lead to treatments for muscular diseases. For example, in muscular dystrophy the exhaustion of satellite cells is the principal cause of death.     

Estimation of the dynamic carotid flow in patients with normal radionuclide cerebral perfusion

Summary Radioisotope angioscintigraphy following intravenous injection bolus of ^99mTc-pertechnetate was performed in 49 patients with cerebrovascular disturbances. The region of interest placement on the sequential analog images of both middle cerebral and internal carotid arteries and time-activity curves were displayed on the video monitor. In 35 cases of this group we have noticed symmetrical cerebral perfusion and a significant difference between right and left internal carotid flow, and in 33 cases of which dynamic studies were made stenosis or occlusion of the extracranial part of the carotid internal artery was revealed by the X-ray angiography.     

A priori dietary omega-3 lipid supplementation results in local pancreatic macrophage and pulmonary inflammatory response attenuation in a model of experimental acute edematous pancreatitis (AEP)

BACKGROUND: Acute pancreatitis is often complicated by multiorgan dysfunction, which is postulated to occur in part by macrophage infiltration into the pancreas. Eicosapentaenoic acid (EPA), an omega-3 fatty acid, is the principal biologic component of fish oil and has clinically and experimentally been demonstrated to be anti-inflammatory. We hypothesized that dietary EPA supplementation before the induction of pancreatitis would attenuate both M-mediated local pancreatic and systemic pulmonary inflammatory response in an in vivo model of acute edematous pancreatitis (AEP). METHODS: Male Sprague-Dawley (SD) rats were pretreated 2 times per day with oral gavage with EPA (omega-3 fatty acid; 5 mg/kg/dose) or omega-6 fatty acid control (5 mg/kg/dose) or saline (equal volume) for 2 weeks. AEP was induced in omega-3, omega-6, and saline pretreated rats by 5 hourly subcutaneous (SC) injections of cerulein. Pancreas, lung, and serum were harvested 3 hours after the last cerulein injection. Severity of pancreatitis was confirmed by serum amylase and by histopathologic score. Pancreatic macrophage infiltration was assessed by confocal fluorescent microscopy, and pulmonary leukocyte respiratory burst (LRB) analysis was performed on mononuclear cells obtained from bronchioalveolar lavage (BAL). RESULTS: All animals demonstrated acute pancreatitis through hyperamylasemia and histopathologic examination. Confocal analysis demonstrated significantly lower macrophage infiltration, and BAL analysis by flow cytometry demonstrated significantly lower (p < .05) LRB in the omega-3-treated group compared with the omega-6 and the saline pancreatitis group. CONCLUSIONS: Attenuation of both pancreatic MPhi inflammatory response and pulmonary leukocyte respiratory burst in AEP by EPA supports further investigation into the potential role for EPA dietary supplementation in the progression of pancreatitis-associated sequelae.     

Extrinsic neural contribution to ileal peptide YY (PYY) release.

Peptide YY (PYY) release into the ileal lumen is stimulated by cholecystokinin (CCK) and glucose ingestion. Previous data have implicated vagal activity in the mediation of PYY release into both the systemic circulation and the ileal lumen. The present study was designed to evaluate extrinsic neural involvement in CCK and glucose-stimulated circulating and ileal intraluminal PYY release. Distal ileal Thiry-Vella loops (TVL) of 25 cm were created in seven mongrel dogs. On separate days fasted dogs were given continuous infusions of CCK at 500 ng/kg/hr during the first hour of the study or an oral glucose (1.5 g/kg) tolerance test (OGTT) was performed. Peripheral blood samples and ileal effusates were collected before tests and following either CCK or glucose stimulation for 120 min at 20-min intervals. Ileal PYY recoveries were measured by the instillation and collection of 20 cc of normal saline from the TVL for each 20-min period. The dogs were again tested after surgical denervation of the TVL. OGTT resulted in a significant rise of PYY recovery from the TVL (P less than 0.05), while not affecting circulating PYY. Intravenous CCK resulted in significant increases in both plasma and ileal PYY concentrations (P less than 0.05). Denervation of the TVL decreased PYY recovery from the TVL after both CCK and OGTT, whereas this procedure did not affect circulating PYY levels or basal luminal levels. These data demonstrate the inhibition of CCK- and glucose-stimulated ileal PYY recovery from denervated ileal loops. The extrinsic neural pathways are involved in the mediation of glucose- and CCK-stimulated mechanisms for ileal PYY release.     

Pseudomyxoma peritonei originating from urachus—case report and review of the literature

Pseudomyxoma peritonei (pmp) is a rare clinical condition defined as extensive intraperitoneal spread of mucus associated with a variety of mucinous tumours of varying biologic behavior. Although appendix or ovaries have usually been implicated as the primary site, cases have been reported in association with neoplastic lesions of other sites. Pseudomyxoma peritonei originating from urachal remnants is a unique entity, reported only 18 times in the English literature thus far. Considering the rarity of the lesion, we report the case of a 50-year-old man surgically treated for pmp associated with a low-grade mucinous urachal neoplasm. Unique aspects of case are the low histologic aggressiveness of the causative lesion (reported only twice worldwide) and the early stage of the disease, with a relatively small amount of intraperitoneal free mucin. Review of the literature about pmp in general and a collation of previously reported cases of pmp originating from the urachus are presented and discussed.     

Catalyzing stem cell research

In 2001, the Stem Cell Network was the first of its kind, a bold initiative to forge and nurture pan-Canadian collaborations involving researchers, engineers, clinicians and private and public sector partners. Canada's broad and deep pool of stem cell talent proved to be a fertile ground for such an initiative, giving rise to a strong, thriving network that, 7 years later, can list innovative cell expansion and screening technologies, early-phase clinical trials for stroke, pulmonary hypertension, muscular dystrophy and cornea replacement, and leading discourse on ethical, legal and social issues among its accomplishments. As it moves into its second and final phase of funding, the Stem Cell Network continues to push boundaries and has set its sights on overcoming the obstacles that impede the transfer of research findings to clinical applications, commercial products and public policy.