Search

Cellular senescence is emerging as a key mechanism of age-related vascular endothelial dysfunction, but evidence in healthy humans is lacking. Moreover, the influence of lifestyle factors such as habitual exercise on endothelial cell (EC) senescence is unknown. We tested the hypothesis that EC senescence increases with sedentary, but not physically active, aging and is associated with vascular endothelial dysfunction. Protein expression (quantitative immunofluorescence) of p53, a transcription factor related to increased cellular senescence, and the cyclin-dependent kinase inhibitors p21 and p16 were 116%, 119%, and 128% greater (all P < 0.05), respectively, in ECs obtained from antecubital veins of older sedentary (60 ± 1 yr, n = 12) versus young sedentary (22 ± 1 yr, n = 9) adults. These age-related differences were not present (all P > 0.05) in venous ECs from older exercising adults (57 ± 1 yr, n = 13). Furthermore, venous EC protein levels of p53 ( r = −0.49, P = 0.003), p21 ( r = −0.38, P = 0.03), and p16 ( r = −0.58, P = 0.002) were inversely associated with vascular endothelial function (brachial artery flow-mediated dilation). Similarly, protein expression of p53 and p21 was 26% and 23% higher (both P < 0.05), respectively, in ECs sampled from brachial arteries of healthy older sedentary (63 ± 1 yr, n = 18) versus young sedentary (25 ± 1 yr, n = 9) adults; age-related changes in arterial EC p53 and p21 expression were not observed ( P > 0.05) in older habitually exercising adults (59 ± 1 yr, n = 14). These data indicate that EC senescence is associated with sedentary aging and is linked to endothelial dysfunction. Moreover, these data suggest that prevention of EC senescence may be one mechanism by which aerobic exercise protects against endothelial dysfunction with age. NEW & NOTEWORTHY Our study provides novel evidence in humans of increased endothelial cell senescence with sedentary aging, which is associated with impaired vascular endothelial function. Furthermore, our data suggest an absence of age-related increases in endothelial cell senescence in older exercising adults, which is linked with preserved vascular endothelial function. Listen to this article's corresponding podcast at http://ajpheart.podbean.com/e/aging-exercise-and-endothelial-cell-senescence/ .

Background and aims Limited data are available regarding fully covered metal stents in the management of malignant distal biliary strictures. The aim of this study was to evaluate the safety of a fully covered self-expanding metal stent (FCSEMS) with flared ends, in treating malignant biliary strictures. We report our long-term retrospective analysis from 6 centers. Methods A total of 260 patients (142 males, median age 68 y) underwent endoscopic retrograde cholangiopancreatography with placement of FCSEMS (WallFlex; Boston Scientific, Natick, MA) for the palliation of obstructive jaundice in the setting of pancreatic adenocarcinoma (169), metastatic disease (36), cholangiocarcinoma (23), ampullary cancer (19), or other (13). Patients were evaluated clinically in follow-up and biochemical tests of liver function were obtained. Data were recorded for the following variables: patient survival, duration of stent patency, the need for subsequent biliary intervention, and complications. Results A total of 266 FCSEMS were placed in 260 patients. There was a median survival of 100 days (range, 7 to 531 d). There was a mean follow-up of 134±118 days (range, 4 to 519 d). Biliary decompression was successful in 252 patients (97%). At the end of the study period, 121 were alive with a patent stent, 65 patients died with a patent stent, 40 patients were successfully bridged to surgery, 8 patients had their patent stent removed and had no need for further stenting, and 18 patients were lost to follow-up. Five patients who had a successfully placed FCSEMS were considered a failure due to the following reason: migration (2), cholangitis (1), stent occlusion (1), and removal for management of proximal biliary obstruction (1). Two additional patients experienced migration that did not require FCSEMS removal or replacement. Stent replacement was required in 10 patients, of whom 6 had a second FCSEMS placed. The remaining 4 were in the failure group and underwent replacement with either uncovered stents or plastic stents. Other complications, managed conservatively, included pain (2), postendoscopic retrograde cholangiopancreatography pancreatitis (4), fever (1), retroperitoneal perforation (1), and postsphincterotomy bleeding (1). The mean patency duration was 328 days (SE 19.04). The patency percentage was 83% at 3 months, 63% at 6 months, and 48.5% at 12 months. Conclusions In the management of malignant distal biliary strictures, the fully covered WallFlex stent has acceptable patency and complication rates. Further long-term prospective data are required to confirm this observation.

Uncertainty as to the functional role of the D(3) dopamine receptor, due primarily to a paucity of selective agonists or antagonists, is being addressed in mice with targeted gene deletion ("knockout") thereof. This study describes, for the first time, the phenotype of congenic D(3)-null mice. Initially, 129/Sv x C57BL/6 D(3)-null mice were backcrossed 14 times onto C57BL/6; they were then assessed using an ethologically based approach which resolves all topographies of behaviour within the mouse repertoire. The ethogram of D(3)-null mice, on comparison with wildtypes, was characterised by no alteration in any topography of behaviour over an initial period of exploration; subsequent assessment over several hours revealed only increased rearing among females due to delayed habituation. Low doses of the selective D(2)-like agonist RU 24213 (0.016-0.25 mg/kg) inhibited topographies of exploratory behaviour; this effect was diminished in D(3)-null mice only when investigated following prolonged habituation, and then only for certain topographies of behaviour, primarily sniffing and rearing. High doses of RU 24213 (0.1-12.5 mg/kg) induced stereotyped sniffing and "ponderous" locomotion, while the selective D(1)-like agonist SKF 83959 (0.016-2.0 mg/kg) promoted characteristic grooming syntax; these effects did not differ materially between the genotypes. When examined topographically on an essentially congenic C57BL/6 background (0.005% 129/Sv), the resultant phenotype indicated essential conservation of the mouse ethogram, high-dose D(2)-like stimulatory effects, and D(1)-like stimulatory effects in the absence of D(3) receptors. A role for D(3) receptors in inhibitory processes appeared topographically circumscribed and only when baseline levels of behaviour were low.

A novel system was used to assess the role of D 1 -like dopamine receptors in distinct topographies of orofacial movements in mice with congenic D 1A receptor knockout. Under spontaneous conditions, vertical jaw movements in wildtypes declined with time at a rate that was reduced in D 1A mutants, while horizontal jaw movements emerged progressively in wildtypes but not in D 1A mutants; tongue protrusions were absent in D 1A mutants, while incisor chattering was initially reduced in D 1A mutants but rose subsequently to reach the level of wildtypes. D 1A receptors exert a topographically specific role in regulating individual spontaneous orofacial movements, and these involve interactions with psychomotor processes which ‘sculpt’ behavioural change over time. The anomalous D 1 -like agonist SK&F 83959, which fails to stimulate, and indeed inhibits the stimulation of adenylyl cyclase induced by dopamine, readily stimulated vertical jaw movements, tongue protrusions and incisor chattering, and these response topographies were absent in D 1A mutants. These results suggest that D 1A receptors may exert some form of permissive role over orofacial topographies initiated via a novel, putative D 1 -like site not linked to adenylyl cyclase, or that some D 1A receptors might be coupled to a transduction system other than adenylyl cyclase.

A novel procedure for the assessment of orofacial movement topographies in mice was used to study, for the first time, the individual and interactive involvement of dopamine D 1 -like vs. D 2 -like receptors in their regulation. The dopamine D 1 -like receptor agonists A 68930 ([1 R ,3 S ]-1-aminomethyl-5,6-dihydroxy-3-phenyl-isochroman) and SK&F 83959 (3-methyl-6-chloro-7,8-dihydroxy-1-[3-methyl-phenyl]-2,3,4,5-tetrahydro-1 H -3-benzazepine) each induced vertical jaw movements with tongue protrusions and incisor chattering. The dopamine D 1 -like receptor antagonists SCH 23390 ([ R ]-3-methyl-7-chloro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1 H -3-benzazepine) and BW 737C ([ S ]-6-chloro-1-[2,5-dimethoxy-4-propylbenzyl]-7-hydroxy-2-methyl-1,2,3,4-tetrahydroisoquinoline) antagonised these responses, while the dopamine D 2 -like receptor antagonist YM 09151-2 ( cis - N -[1-benzyl-2-methyl-pyrrolidin-3-yl]-5-chloro-2-methoxy-4-methylaminobenzamide) attenuated those to SK&F 83959 and released horizontal jaw movements. These findings suggest some role for a dopamine D 1 -like receptor that is coupled to a transduction system other than/additional to adenylyl cyclase, and for dopamine D 1 -like:D 2 -like receptor interactions, in the regulation of individual orofacial movement topographies in the mouse. This methodology will allow the use of knockout mice to clarify the roles of individual dopamine receptor subtypes in their regulation.

Background: Covered self-expanding metal stents are being used more frequently in benign biliary strictures (BBS). We report the results of a multicenter study with fully covered self-expanding metal stent (FCSEMS) placement for the management of BBS. Aim: To prospectively evaluate the efficacy and safety of FCSEMS in the management of BBS. Patients and Methods: Patients with BBS from 6 tertiary care centers who received FCSEMS with flared ends between April 2009 and October 2010 were included in this retrospective study. Patients and Methods: Efficacy was measured after removal of FCSEMS by evaluating stricture resolution on the basis of symptom resolution, imaging, laboratory studies, and/or choledochoscopy at removal. Safety profile was evaluated by assessing postprocedural complications. Results: A total of 133 patients (78, 58.6% males) with a mean age of 59.2±14.8 years with BBS received stents. Of the 133 stents placed, 97 (72.9%) were removed after a mean stent duration of 95.5±48.7 days. Stricture resolution after FCSEMS removal was as follows: postsurgical, 11/12 (91.6%); gallstone-related disease, 16/19 (84.2%); chronic pancreatitis, 26/31 (80.7%); other etiology, 4/5 (80.0%); and anastomotic strictures, 19/31(61.2%). Ninety-four patients were included in the logistic regression analyses. Patients who had indwelling stents for >90 days were 4.3 times more likely to have resolved strictures [odds ratio, 4.3 (95% confidence interval, 1.24-15.09)] and patients with nonmigrated stents were 5.4 times more likely to have resolved strictures [odds ratio, 5.4 (95% confidence interval, 1.001-29.29)]. Conclusions: FCSEMS for BBS had an acceptable rate of stricture resolution for postsurgical strictures, gallstone-related strictures, and those due to chronic pancreatitis. Predictors for stricture resolution include longer indwell time and absence of migration. Further study is warranted to assess long-term efficacy in a prospective manner with longer than 3-month time of stent indwelling time.

Using a novel system, the role of D2-like dopamine receptors in distinct topographies of orofacial movement was assessed in mutant mice with congenic D2 vs. D3 receptor knockout, and compared with findings in D1A mutants. Under spontaneous conditions, D2 mutants evidenced increased vertical jaw movements and unaltered horizontal jaw movements, with reductions in tongue protrusions and incisor chattering; in D3 mutants, only incisor chattering was reduced. Given previous evidence that D1A mutants show reduced horizontal but not vertical jaw movements, this indicates that apparent oppositional D1-like:D2-like interactions in the regulation of composited jaw movements may in fact reflect the independent actions of D2 receptors to inhibit vertical jaw movements and of D1A receptors to facilitate horizontal jaw movements. Effects of the D2-like agonist RU 24213 to exert greater reduction in horizontal than in vertical jaw movements were not altered prominently in either D2 or D3 mutants. The D1-like agonists A 68930 and SK&F 83959 induced vertical jaw movements, tongue protrusions, and incisor chattering; induction of tongue protrusions by A 68930 was reduced in D2 mutants. D2 receptors exert topographically specific regulation of orofacial movements in a manner distinct from their D1A counterparts, while D3 receptors exert only minor regulation of such movements. Fil: Tomiyama, Katsunori. Royal College of Surgeons in Ireland; Irlanda. Nihon University School of Dentistry; Japón Fil: Mcnamara, Fergal N.. Royal College of Surgeons in Ireland; Irlanda Fil: Clifford, Jeremiah J.. Royal College of Surgeons in Ireland; Irlanda Fil: Kinsella, Anthony. Dublin Institute of Technology; Irlanda Fil: Drago, John. Monash Medical Centre; Australia Fil: Fuchs, Sara. Weizmann Institute of Science; Israel Fil: Grandy, David K.. Oregon Health Sciences University; Estados Unidos Fil: Low, Malcolm J.. Oregon Health Sciences University; Estados Unidos Fil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina Fil: Tighe, Orna. Royal College of Surgeons in Ireland; Irlanda Fil: Croke, David T.. Royal College of Surgeons in Ireland; Irlanda Fil: Koshikawa, Noriaki. Nihon University School of Dentistry; Japón Fil: Waddington, John L.. Royal College of Surgeons in Ireland; Irlanda

Congenic (10 backcrosses into C57BL/6J) mutants with targeted gene deletion of DARPP-32, a neuronal phosphoprotein regarded as an essential mediator of the biological effects of dopamine (DA), were assessed phenotypically using an ethologically based approach that resolves all topographies of behavior in the mouse repertoire. Over initial exploration, female, but not male, DARPP-32 mutants evidenced increased locomotion and decreased grooming, while a decrease in rearing seated was evident in mutants of both genders; continuing assessment over several hours did not reveal additional phenotypic effects. Following challenge with the nonselective DA receptor agonist apomorphine, low doses were associated with reduced levels of sniffing, grooming, total rearing, and rearing seated in DARPP-32 mutants relative to wildtypes; this would suggest some role for DARPP-32 in mediating the biological effects of presynaptic D(2)-like autoreceptor or inhibitory postsynaptic D(2)-like receptor activation. Following challenge with higher doses, while stereotyped sniffing and locomotion with chewing was largely unaltered, the additional murine response of Straub tail was essentially abolished in DARPP-32 mutants, indicating some specific involvement of DARPP-32 in mediating this topography of behavior; additionally, there were overall reductions in levels of sniffing, total rearing, rearing seated, and grooming in DARPP-32 mutants that were unrelated to the dose of apomorphine administered, indicating broader topographical effects following the stress of the injection procedure relative to more naturalistic conditions. The developmental absence of DARPP-32 following targeted gene deletion appears to be associated with compensatory processes that maintain certain topographies of spontaneous and agonist-induced DAergic function, while other topographies remain impaired.

Extracts of tissue showed that prostatic carcinomas contain less leucine aminopeptidase activity than benign prostatic hyperplasia. This is true when activity is expressed as specific activity (P = 0.0033), specific activity/% epithelium (P = 0.0007), activity/wet weight of tissue (P = 0.0028), or activity/wet weight of tissue/% epithelium (P = 0.0005). Almost all histochemically demonstrable activity is located in the epithelium. Enzymatic activities in extracts and in histochemical preparations showed similar differences between carcinoma and benign prostatic hyperplasia and were related (R = -0.38, P = 0.0400) to Gleason's grades. The transurethrally resected prostate cancers studied contained no well-differentiated tumors and a high proportion of poorly differentiated tumors. Histochemical activity is absent in most prostatic carcinomas and decreased in others. This observation is particularly interesting in view of the growing knowledge of tumor suppressor genes.

Obtaining venous access continues to be one of the most difficult problems faced by a physician caring for the pediatric patient in cardiac arrest. Our study examined the use of the intraosseous route (through the bone) to obtain venous access for sodium bicarbonate administration in a cardiac arrest model. Ventricular fibrillation was induced in 23 domestic swine. Cardiopulmonary resuscitation was performed for five minutes and sodium bicarbonate (1 mEq/kg) was administered through a peripheral IV line (n = 6), a central IV line (n = 5), or intraosseously (n = 6). Controls (n = 6) did not receive bicarbonate. Blood pH was sampled every two minutes for 30 minutes from the right ventricle, left ventricle, and femoral artery. An analysis of variance revealed that the central and intraosseous routes were significantly different (P less than .05) from the peripheral group, and that all three groups were significantly different (P less than .05) from the control. Pathology studies revealed only minor damage to bone when sodium bicarbonate was administered intraosseously. These data demonstrate that the intraosseous route is a rapid and effective alternative for venous access in a cardiac arrest model.