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10 result(s) for "Somers, Pamela"
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Impact of Detergent-Based Decellularization Methods on Porcine Tissues for Heart Valve Engineering
To date an optimal decellularization protocol of heart valve leaflets (HVL) and pericardia (PER) with an adequate preservation of the extracellular matrix (ECM) is still lacking. This study compares a 4 day Triton X-100-based protocol with faster SDC-based protocols for the decellularization of cardiac tissues. Decellularized and non-treated HVL and PER were processed for histological, biochemical and mechanical analysis to determine the effect of these agents on the structure, ECM components, and biomechanical properties. Tissues treated with SDC-based protocols still showed nuclear material, whereas tissues treated with Triton X-100 1% + ENZ ± TRYP were completely cell free. For both decellularized tissues, an almost complete washout of glycosaminoglycans, a reduction of soluble collagen and an alteration of the surface ultrastructure was observed. Interestingly, only the elastic fibers of pericardial tissue were affected and this tissue had a decreased maximum load. This study showed that both detergents had a similar impact on the ECM. However, Triton X-100 1% +DNase/RNase (ENZ) ± Trypsin (TRYP) is the only protocol that generated completely cell free bioscaffolds. Also, our study clearly demonstrated that the decellularization agents have more impact on pericardial tissues than on heart valve leaflets. Thus, for the purpose of tissue engineering of heart valves, it is advisable to use valvular rather than pericardial matrices.
Influence of intracoronary attenuation on coronary plaque measurements using multislice computed tomography: observations in an ex vivo model of coronary computed tomography angiography
Assessment of attenuation (measured in Hounsfield units, HU) of human coronary plaques was performed using multislice computed tomography (MSCT) in an ex vivo model. In three ex vivo specimens of left coronary arteries in oil, MSCT was performed after intracoronary injection of four solutions of contrast material (400 mgI/ml iomeprol). The four solutions were diluted as follows: 1/infinity, 1/200, 1/80, and 1/20. All scans were performed with the following parameters: slices/collimation 16/0.75 mm, rotation time 375 ms. Each specimen was scored for the presence of atherosclerotic plaques. In each plaque the attenuation was measured in four regions of interest for lumen, plaque (non-calcified thickening of the vessel wall), calcium, and surrounding (oil surrounding the vessel). The results were compared with a one-way analysis of variance test and were correlated with Pearson's test. There were no significant differences in the attenuation of calcium and oil in the four solutions. The mean attenuation in the four solutions for lumen (35+/-10, 91+/-7, 246+/-18, 511+/-89 HU) and plaque (22+/-22, 50+/-26, 107+/-36, 152+/-67 HU) was significantly different between each decreasing dilution (p<0.001). The mean attenuation of lumen and plaque of coronary plaques showed high correlation, while the values were significantly different (r=0.73; p<0.001). Intracoronary attenuation modifies significantly the attenuation of plaques assessed with MSCT.
Influence of convolution filtering on coronary plaque attenuation values: observations in an ex vivo model of multislice computed tomography coronary angiography
Attenuation variability (measured in Hounsfield Units, HU) of human coronary plaques using multislice computed tomography (MSCT) was evaluated in an ex vivo model with increasing convolution kernels. MSCT was performed in seven ex vivo left coronary arteries sunk into oil followingthe instillation of saline (1/infinity) and a 1/50 solution of contrast material (400 mgI/ml iomeprol). Scan parameters were: slices/collimation, 16/0.75 mm; rotation time, 375 ms. Four convolution kernels were used: b30f-smooth, b36f-medium smooth, b46f-medium and b60f-sharp. An experienced radiologist scored for the presence of plaques and measured the attenuation in lumen, calcified and noncalcified plaques and the surrounding oil. The results were compared by the ANOVA test and correlated with Pearson's test. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. The mean attenuation values were significantly different between the four filters (p < 0.0001) in each structure with both solutions. After clustering for the filter, all of the noncalcified plaque values (20.8 +/- 39.1, 14.2 +/- 35.8, 14.0 +/- 32.0, 3.2 +/- 32.4 HU with saline; 74.7 +/- 66.6, 68.2 +/- 63.3, 66.3 +/- 66.5, 48.5 +/- 60.0 HU in contrast solution) were significantly different, with the exception of the pair b36f-b46f, for which a moderate-high correlation was generally found. Improved SNRs and CNRs were achieved by b30f and b46f. The use of different convolution filters significantly modifief the attenuation values, while sharper filtering increased the calcified plaque attenuation and reduced the noncalcified plaque attenuation.
Gamma Radiation Alters the Ultrastructure in Tissue-Engineered Heart Valve Scaffolds
Objectives: Xenogenic extracellular heart valve matrices have been suggested as scaffolds for tissue engineering. However, these matrices are immunogenic and stimulate an intense cell-mediated immune response and calcification. Mitigating the immunogenicity was attempted by different doses of gamma irradiation. Methods: Mechanical properties of gamma-irradiated porcine matrices and control matrices (nonirradiated) were examined by tensile strength testing. Irradiated matrices (1, 10, 50, and 100 gray [Gy]) and control matrices were implanted subcutaneously in Wistar rats ( n  = 20). After 24 h, 1, 2, 3, and 4 weeks the explants were examined by light microscopy and transmission electron microscopy. Calcium (Ca) content was determined using inductively coupled plasma–mass spectrometry. Antibody reaction against porcine tissue in the rat serum was determined. Results: Tensile strength increased in irradiated matrices at the expense of elasticity. Ten gray–irradiated leaflets showed minimal lymphocytic inflammatory infiltration with preservation of ultrastructure. Ca levels after 2 weeks were as follows: control (0 Gy), 388 ± 264 μg/mg; 1 Gy, 240 ± 95 μg/mg; 10 Gy, 188 ± 54 μg/mg; 50 Gy, 289 ± 94 μg/mg; 100 Gy, 651 ± 57 μg/mg. All implants still elicit an antibody immunoglobulin G reaction. Conclusions: Exposure to 10 Gy gamma irradiation reduces lymphocytic inflammatory infiltrates and Ca levels in acellular porcine matrices with preservation of structural integrity. This could prolong the durability of these matrices.
Smooth Muscle Cell Hypertrophy in Varicose Veins Is Associated with Expression of Estrogen Receptor-
Varicose veins are characterized by dilated and thickened vein walls. This study examined whether the changes that occur in varicose veins are associated with smooth muscle cell (SMC) hypertrophy, cellular proliferation or apoptosis. Moreover, the association between SMC hypertrophy and the expression of the estrogen receptor-² (ER²) was investigated. Varicose veins were obtained from male patients during vascular stripping surgery (n = 11) and nonvaricose veins during coronary bypass surgery, also from male subjects (n = 12). The cellular volume of the SMC in both the longitudinal and circular layer of the vessel wall was measured using stereological methods. Apoptosis was detected using the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling) technique. SMC proliferation and ER² expression were investigated by immunohistochemistry. Neither in the longitudinal nor in the circular layer of the varicose vein wall were signs of apoptosis or proliferation present. However, the mean cellular volume of the SMC in the circular layer of the varicose veins was strongly increased (5,291 ± 363 ¼m3) as compared to non-varicose veins (2,812 ± 212 ¼m3, p < 0.001). Moreover, ER² expression in the circular layer of varicose veins (63 ± 4%) significantly differed from nonvaricose veins (39 ± 4%; p = 0.001). Interestingly, the SMC volume correlated with ER² expression (r = 0.71, p < 0.001). These data show that cell death or proliferation of SMC do not, or only rarely, occur in varicose veins. However, remodeling of varicose veins can mainly be attributed to increased volumes of the SMC of the circular layer and this increase correlates with ER² expression. Copyright © 2005 S. Karger AG, Basel
Smooth Muscle Cell Hypertrophy in Varicose Veins Is Associated with Expression of Estrogen Receptor-β
Varicose veins are characterized by dilated and thickened vein walls. This study examined whether the changes that occur in varicose veins are associated with smooth muscle cell (SMC) hypertrophy, cellular proliferation or apoptosis. Moreover, the association between SMC hypertrophy and the expression of the estrogen receptor-β (ERβ) was investigated. Varicose veins were obtained from male patients during vascular stripping surgery (n = 11) and nonvaricose veins during coronary bypass surgery, also from male subjects (n = 12). The cellular volume of the SMC in both the longitudinal and circular layer of the vessel wall was measured using stereological methods. Apoptosis was detected using the TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling) technique. SMC proliferation and ERβ expression were investigated by immunohistochemistry. Neither in the longitudinal nor in the circular layer of the varicose vein wall were signs of apoptosis or proliferation present. However, the mean cellular volume of the SMC in the circular layer of the varicose veins was strongly increased (5,291 ± 363 µm 3 ) as compared to non-varicose veins (2,812 ± 212 µm 3 , p < 0.001). Moreover, ERβ expression in the circular layer of varicose veins (63 ± 4%) significantly differed from nonvaricose veins (39 ± 4%; p = 0.001). Interestingly, the SMC volume correlated with ERβ expression (r = 0.71, p < 0.001). These data show that cell death or proliferation of SMC do not, or only rarely, occur in varicose veins. However, remodeling of varicose veins can mainly be attributed to increased volumes of the SMC of the circular layer and this increase correlates with ERβ expression.
MINI REVIEWS
Under Barry Kyle's direction, this is one of the most visually hypnotic Shakespearean productions I've ever seen. Dramatically things are less exciting. Jay Goede and Marin Hinkle are attractive and ardent as the doomed lovers, although there are times when they just shovel emotion on top of the words. Jean Stapleton is charming and funny as Juliet's nurse and Ted van Griethuysen makes a full-blooded character out of Juliet's father, but in general the cast is hit-and-miss. - L.R.
Diagnosis and management of glycogen storage disease type I: a practice guideline of the American College of Medical Genetics and Genomics
Disclaimer: This guideline is designed primarily as an educational resource for clinicians to help them provide quality medical services. Adherence to this guideline is completely voluntary and does not necessarily ensure a successful medical outcome. This guideline should not be considered inclusive of all proper procedures and tests or exclusive of other procedures and tests that are reasonably directed toward obtaining the same results. In determining the propriety of any specific procedure or test, the clinician should apply his or her own professional judgment to the specific clinical circumstances presented by the individual patient or specimen. Clinicians are encouraged to document the reasons for the use of a particular procedure or test, whether or not it is in conformance with this guideline. Clinicians also are advised to take notice of the date this guideline was adopted and to consider other medical and scientific information that becomes available after that date. It also would be prudent to consider whether intellectual property interests may restrict the performance of certain tests and other procedures. Purpose: Glycogen storage disease type I (GSD I) is a rare disease of variable clinical severity that primarily affects the liver and kidney. It is caused by deficient activity of the glucose 6-phosphatase enzyme (GSD Ia) or a deficiency in the microsomal transport proteins for glucose 6-phosphate (GSD Ib), resulting in excessive accumulation of glycogen and fat in the liver, kidney, and intestinal mucosa. Patients with GSD I have a wide spectrum of clinical manifestations, including hepatomegaly, hypoglycemia, lactic acidemia, hyperlipidemia, hyperuricemia, and growth retardation. Individuals with GSD type Ia typically have symptoms related to hypoglycemia in infancy when the interval between feedings is extended to 3–4 hours. Other manifestations of the disease vary in age of onset, rate of disease progression, and severity. In addition, patients with type Ib have neutropenia, impaired neutrophil function, and inflammatory bowel disease. This guideline for the management of GSD I was developed as an educational resource for health-care providers to facilitate prompt, accurate diagnosis and appropriate management of patients. Methods: A national group of experts in various aspects of GSD I met to review the evidence base from the scientific literature and provided their expert opinions. Consensus was developed in each area of diagnosis, treatment, and management. Results: This management guideline specifically addresses evaluation and diagnosis across multiple organ systems (hepatic, kidney, gastrointestinal/nutrition, hematologic, cardiovascular, reproductive) involved in GSD I. Conditions to consider in the differential diagnosis stemming from presenting features and diagnostic algorithms are discussed. Aspects of diagnostic evaluation and nutritional and medical management, including care coordination, genetic counseling, hepatic and renal transplantation, and prenatal diagnosis, are also addressed. Conclusion: A guideline that facilitates accurate diagnosis and optimal management of patients with GSD I was developed. This guideline helps health-care providers recognize patients with all forms of GSD I, expedite diagnosis, and minimize adverse sequelae from delayed diagnosis and inappropriate management. It also helps to identify gaps in scientific knowledge that exist today and suggests future studies. Genet Med 16 11.
THE FLORA OF PENIKESE ISLAND, MASSACHUSETTS: THE FIFTH SURVEY (1998—1999), WITH EMPHASIS ON THE WOODY VEGETATION
Five vascular plant surveys have been made between 1873 and 1999 on Penikese, one of the Elizabeth Islands (Massachusetts). The five surveys have noted a total of 326 species, the most recent survey, 218 species. Almost half of the species noted are alien on all five survey lists. Four rare (state-listed) native species were found in 1998—1999. The most significant change in the island's vegetation over 125 years is the great increase in woody vines and shrubs following cessation of the farming that stripped the island of its presettlement forest. Fifteen woody species, some of them recent introductions, are thought to be increasing. Two of the island's ponds—Tubs and South—are brackish, supratidal pools without vascular plants. Four ponds—North, Leper, Tern, and Typha—are fresh, shallow, and usually dry up annually, at which time their bottoms support a dense, diverse flora. Salt marsh species and numbers are fewer than formerly. There is evidence that the island as plant habitat is drier than in the past, perhaps as a result of the increase in woody vegetation. For instance, ferns, once common on Penikese, are now almost wholly absent. Certain species common on nearby islands are missing; for instance, no blueberries or other ericads are found on Penikese. In the absence of further disturbance, it is possible that Penikese will again become forested with red cedar (Juniperus virginiana) as a presettlement account of 1602 describes it, but island-wide burns are suggested for destroying invasive woody plants and encouraging native grasses. Such burns might also restore former tern-nesting sites to usefulness.
RE-ELECT ROLAND
Cast your vote in Somers for Selectman Phil Roland on Nov. 2. He has served in this position for 10 years and has proved himself to be highly competent and dedicated. We need his experience in handling the problems unique to Somers with his honest, common-sense approach.