Endoscopic off-pump aortic valve replacement: does the pericardial cuff improve the sutureless closure of left ventricular access?

OBJECTIVE: Off-pump trans left ventricular approach provides more precise deployment of stented aortic valve of any size with respect to the endovascular replacement. One of the key steps of this procedure is the ventricle repair after catheter withdrawing. We designed an animal study to compare the consistency of a sutureless repair of the left ventricle access using nitinol occluder with and without pericardial cuff on the ventricular side. METHODS: Material description: The Amplatz-nitinol occluder consists of two square heads squeezing ventricle wall in between them, sealing the defect. To improve its sealing property, a pericardial patch was sutured to the ventricular head of the occluder. Animal study setup: In adult pigs, a 30F sheath was inserted into the epigastric area through the cardiac apex, up to the left ventricle, simulating the approach for off-pump aortic valve replacement. The sheath was then removed and the ventricle closed with standard occluder in half of the animals, and cuffed occluder in the other half. Animals were followed-up for 3h, collecting haemodynamics data and pericardial bleeding. RESULTS: Device was successfully deployed in 12 animals in less than 1min. In the group where the standard occluder was used, bleeding during the deployment was 80+/-20ml and after the deployment was 800+/-20ml over 3h. In the group where the cuffed occluder was used, bleeding during the deployment was 85+/-20ml and after the deployment was 100+/-5ml over 3h. In the cuffed group, bleeding was significantly lower than the standard group, p-value being <0.001. CONCLUSIONS: The occluder is easy to use and the pericardial cuff dramatically increases its efficacy as demonstrated by a significant reduction of blood loss. The cuffed occluder opens the way for endoscopic, off-pump, transventricular aortic valve replacement.

Intrapericardial pacemaker in a 2-kilogram newborn.

A 2-kilogram child had a pacemaker implanted by a subxyphoid approach with the generator located under the rectus sheath. Days later, the battery eroded the abdominal wall and the peritoneum. The whole system was removed and a new one was implanted inside the pericardium on an emergent basis.

Low transformation growth factor-β1 production and collagen synthesis correlate with the lack of hepatic periportal fibrosis development in undernourished mice infected with Schistosoma mansoni

Undernourished mice infected (UI) submitted to low and long-lasting infections by Schistosoma mansoni are unable to develop the hepatic periportal fibrosis that is equivalent to Symmers’ fibrosis in humans. In this report, the effects of the host’s nutritional status on parasite (worm load, egg viability and maturation) and host (growth curves, biology, collagen synthesis and characteristics of the immunological response) were studied and these are considered as interdependent factors influencing the amount and distribution of fibrous tissue in hepatic periovular granulomas and portal spaces. The nutritional status of the host influenced the low body weight and low parasite burden detected in UI mice as well as the number, viability and maturation of released eggs. The reduced oviposition and increased number of degenerated or dead eggs were associated with low protein synthesis detected in deficient hosts, which likely induced the observed decrease in transformation growth factor (TGF)-β1 and liver collagen. Despite the reduced number of mature eggs in UI mice, the activation of TGF-β1 and hepatic stellate cells occurred regardless of the unviability of most miracidia, due to stimulation by fibrogenic proteins and eggshell glycoproteins. However, changes in the repair mechanisms influenced by the nutritional status in deficient animals may account for the decreased liver collagen detected in the present study.

Accidental cross-clamping of the superior vena cava: management and BIS evolution.

The case of a 38-year old man with recurrent adenocarcinoma of the right lung and infiltration of the thoracic wall, who underwent a right pneumonectomy with thoracic wall resection, is described. Dissection of the right pulmonary hilous was extremely difficult due to the previous operations. The superior vena cava (SVC) was accidentally ligated, resulting in profound hypotension and increased venous pressure in the internal jugular vein. Immediate blood aspiration through a 8.5-French introducer sheath lowered the venous congestion. After the SVC was cross-clamped, the Bispectral Index (BIS) acutely decreased to 0 and remained low during the resuscitation. Over the next 5 hours, BIS was directly affected by mean arterial pressure. Four days postoperatively, the patient was neurologically intact.

Superficial Acral Fibromyxoma involving the nail's apparatus. Case report and literature review.

Superficial Acral Fibromyxoma is a rare tumor of soft tissues. It is a relatively new entity described in 2001 by Fetsch et al. It probably represents a fibrohistiocytic tumor with less than 170 described cases. We bring a new case of SAF on the 5th toe of the right foot, in a 43-year-old woman. After surgical excision with safety margins which included the nail apparatus, it has not recurred (22 months of follow up). We carried out a review of the location of all SAF published up to the present day.

MDM2 and CDK4 immunohistochemistry is a valuable tool in the differential diagnosis of low-grade osteosarcomas and other primary fibro-osseous lesions of the bone.

Low-grade osteosarcoma is a rare malignancy that may be subdivided into two main subgroups on the basis of location in relation to the bone cortex, that is, parosteal osteosarcoma and low-grade central osteosarcoma. Their histological appearance is quite similar and characterized by spindle cell stroma with low-to-moderate cellularity and well-differentiated anastomosing bone trabeculae. Low-grade osteosarcomas have a simple genetic profile with supernumerary ring chromosomes comprising amplification of chromosome 12q13-15, including the cyclin-dependent kinase 4 (CDK4) and murine double-minute type 2 (MDM2) gene region. Low-grade osteosarcoma can be confused with fibrous and fibro-osseous lesions such as fibromatosis and fibrous dysplasia on radiological and histological findings. We investigated MDM2-CDK4 immunohistochemical expression in a series of 72 low-grade osteosarcomas and 107 fibrous or fibro-osseous lesions of the bone or paraosseous soft tissue. The MDM2-CDK4 amplification status of low-grade osteosarcoma was also evaluated by comparative genomic hybridization array in 18 cases, and the MDM2 amplification status was evaluated by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction in 31 cases of benign fibrous and fibro-osseous lesions. MDM2-CDK4 immunostaining and MDM2 amplification by fluorescence in situ hybridization or quantitative real-time polymerase chain reaction were investigated in a control group of 23 cases of primary high-grade bone sarcoma, including 20 conventional high-grade osteosarcomas, two pleomorphic spindle cell sarcomas/malignant fibrous histiocytomas and one leiomyosarcoma. The results showed that MDM2 and/or CDK4 immunoreactivity was present in 89% of low-grade osteosarcoma specimens. All benign fibrous and fibro-osseous lesions and the tumors of the control group were negative for MDM2 and CDK4. These results were consistent with the MDM2 and CDK4 amplification results. In conclusion, immunohistochemical expression of MDM2 and CDK4 is specific and provides sensitive markers for the diagnosis of low-grade osteosarcomas, helping to differentiate them from benign fibrous and fibro-osseous lesions, particularly in cases with atypical radio-clinical presentation and/or limited biopsy samples.

Swimming prevents vulnerable atherosclerotic plaque development in hypertensive 2-kidney, 1-clip mice by modulating angiotensin II type 1 receptor expression independently from hemodynamic changes.

Exercise is known to reduce cardiovascular risk. However, its role on atherosclerotic plaque stabilization is unknown. Apolipoprotein E(-/-) mice with vulnerable (2-kidney, 1-clip: angiotensin [Ang] II-dependent hypertension model) or stable atherosclerotic plaques (1-kidney, 1-clip: Ang II-independent hypertension model and normotensive shams) were used for experiments. Mice swam regularly for 5 weeks and were compared with sedentary controls. Exercised 2-kidney, 1-clip mice developed significantly more stable plaques (thinner fibrous cap, decreased media degeneration, layering, macrophage content, and increased smooth muscle cells) than sedentary controls. Exercise did not affect blood pressure. Conversely, swimming significantly reduced aortic Ang II type 1 receptor mRNA levels, whereas Ang II type 2 receptor expression remained unaffected. Sympathetic tone also significantly diminished in exercised 2-kidney, 1-clip mice compared with sedentary ones; renin and aldosterone levels tended to increase. Ang II type 1 downregulation was not accompanied by improved endothelial function, and no difference in balance among T-helper 1, T-helper 2, and T regulatory cells was observed between sedentary and exercised mice. These results show for the first time, in a mouse model of Ang II-mediated vulnerable plaques, that swimming prevents atherosclerosis progression and plaque vulnerability. This benefit is likely mediated by downregulating aortic Ang II type 1 receptor expression independent from any hemodynamic change. Ang II type 1 downregulation may protect the vessel wall from the Ang II proatherogenic effects. Moreover, data presented herein further emphasize the pivotal and blood pressure-independent role of Ang II in atherogenesis.

Inmunopatología de la esclerosis múltiple.

Multiple sclerosis is an inflammatory demyelinating disease affecting the central nervous system and considered one of the leading causes of disability in young adults. The precise cause of multiple sclerosis is unknown, although the current evidence points towards a combination of genetic and environmental factors leading to an autoimmune response that promotes neuronal degeneration. In this review, we will describe the association between the immune response and neurodegeneration in multiple sclerosis.

Deletion of Sirt3 does not affect atherosclerosis but accelerates weight gain and impairs rapid metabolic adaptation in LDL receptor knockout mice: implications for cardiovascular risk factor development.

Sirt3 is a mitochondrial NAD(+)-dependent deacetylase that governs mitochondrial metabolism and reactive oxygen species homeostasis. Sirt3 deficiency has been reported to accelerate the development of the metabolic syndrome. However, the role of Sirt3 in atherosclerosis remains enigmatic. We aimed to investigate whether Sirt3 deficiency affects atherosclerosis, plaque vulnerability, and metabolic homeostasis. Low-density lipoprotein receptor knockout (LDLR(-/-)) and LDLR/Sirt3 double-knockout (Sirt3(-/-)LDLR(-/-)) mice were fed a high-cholesterol diet (1.25 % w/w) for 12 weeks. Atherosclerosis was assessed en face in thoraco-abdominal aortae and in cross sections of aortic roots. Sirt3 deletion led to hepatic mitochondrial protein hyperacetylation. Unexpectedly, though plasma malondialdehyde levels were elevated in Sirt3-deficient mice, Sirt3 deletion affected neither plaque burden nor features of plaque vulnerability (i.e., fibrous cap thickness and necrotic core diameter). Likewise, plaque macrophage and T cell infiltration as well as endothelial activation remained unaltered. Electron microscopy of aortic walls revealed no difference in mitochondrial microarchitecture between both groups. Interestingly, loss of Sirt3 was associated with accelerated weight gain and an impaired capacity to cope with rapid changes in nutrient supply as assessed by indirect calorimetry. Serum lipid levels and glucose tolerance were unaffected by Sirt3 deletion in LDLR(-/-) mice. Sirt3 deficiency does not affect atherosclerosis in LDLR(-/-) mice. However, Sirt3 controls systemic levels of oxidative stress, limits expedited weight gain, and allows rapid metabolic adaptation. Thus, Sirt3 may contribute to postponing cardiovascular risk factor development.

Towards no-scar cardiac surgery - minimally invasive access through umbilicus for aortic valve replacement.

There is an ever-growing trend towards less-invasive procedures in all fields of medicine. We designed an animal study to prove the concept that trans-apical aortic valve replacement from an incision within the umbilicus through a single channel for instruments is feasible, which would be a major leap towards no-scar cardiac surgery. In three adult pigs, after creating a single 3-cm incision at a place where the human umbilicus would be, we introduced a 30F sheath through a tunnel created by an endoscopic vein-harvesting device up to the cardiac apex, through it and up to the left ventricle simulating the approach for trans-apical aortic valve replacement. We used a standard Amplatz nitinol occluder to seal the defect in ventricle wall later. The animals were followed up for 1h. Blood loss was minimal, and no tamponade occurred in any of the animals. In addition, we performed a test with water column static pressure to evaluate the impact of preclotting on the sealing properties of the occluders: 1 min flow-through was 2860+/-176 ml for the standard occluders and 348+/-56 ml for preclotted occluders (p<0.001).

Caracterització de la fibra Henequén per ser utilitzada com a reforç en materials compostos

La generació massiva de residus plàstics constitueix actualment un gravíssim problemamediambiental. Una de les estratègies desenvolupades per pal•liar-lo consisteix en el reciclatge delsresidus plàstics i la seva posterior utilització en diferents aplicacions en sectors com la construcció.La incorporació de reforços en el material reciclat millora les seves propietats mecàniques. Unpossible reforç són les fibres d'origen vegetal o biofibres, que, a més de millorar tècnicament elproducte, presenten avantatges econòmics i ambientals. Les biofibres són un bon competidor contrales fibres reforçants tradicionals com la fibra de vidre ja que presenten un baix cost, baixa densitat i,per tant, bones propietats específiques, menys equip de processament, alta suavitat,biodegradabilitat i són ecològicament sostenibles, ja que es produeixen a partir de recursos naturals.En aquest treball es fan servir fibres provinents de la pinya de Henequén. Aquestes fibres són unsubproducte del procés per a l’obtenció del licor de Henequén i es volen fer servir com a reforç enmaterials compostos.Ja s’han fet estudis sobre la fibra de Henequén que creix a Mèxic. Aquest projecte s’emmarca dinsuna col•laboració entre la Universitat de Girona i la Universitat Cubana de Holguin, per tal d’estudiarla fibra de Henequén que creix a Cuba

The cervico-thoracic outlet compression syndrome. Analysis of surgical treatment.

Surgical treatment of the thoracic outlet compression syndrome is being presently reconsidered. Until these last few years, there was the choice between two interventions only: scalenotomy, a simple operation entailing no complication, but with a 60% recurrence rate--or the resection of the first rib through an axillary approach, an efficacious intervention which caused, however, serious nervous complications in 14% of treated cases. The follow-up of 75 cases operated for a TOCS reveals to the authors that--all techniques taken into account--results are unsatisfactory in 33% of cases. These failures are due either to technical deficiencies, or to a complication arising in the course of the operation, or to an erroneous diagnosis. The authors resort to surgery only to treat serious vascular syndromes (absolute indication) or invalidating neurological compression syndromes, after failure of physical therapy (relative indication). They propose a cervical approach--the only one enabling a safe dissection of the brachial plexus--a partial scalenectomy, resection of all fibrous bands pressing on nervous trunks, or the resection of a cervical rib. Should the costo-clavicular space appear anatomically too narrow, the first rib, already partially freed by the cervical approach, will be resected through the axillary route.

Mean intrinsic tensile properties of stone groundwood fibers from softwood

Stone groundwood (SGW) is a fibrous matter commonly prepared in a high yield process, and mainly used for papermaking applications. In this work, the use of SGW fibers is explored as reinforcing element of polypropylene (PP) composites. Due to its chemical and superficial features, the use of coupling agents is needed for a good adhesion and stress transfer across the fiber-matrix interface. The intrinsic strength of the reinforcement is a key parameter to predict the mechanical properties of the composite and to perform an interface analysis. The main objective of the present work was the determination of the intrinsic tensile strength of stone groundwood fibers. Coupled and non-coupled PP composites from stone groundwood fibers were prepared. The influence of the surface morphology and the quality at interface on the final properties of the composite was analyzed and compared to that of fiberglass PP composites. The intrinsic tensile properties of stone groundwood fibers, as well as the fiber orientation factor and the interfacial shear strength of the current composites were determined

Renin inhibition by aliskiren prevents atherosclerosis progression: comparison with irbesartan, atenolol, and amlodipine.

Hypertension is associated with increased risk of cardiovascular diseases. Antihypertensive treatment, particularly blockade of the renin-angiotensin system, contributes to prevent atherosclerosis-mediated cardiovascular events. Direct comparison of different antihypertensive treatments on atherosclerosis and particularly plaque stabilization is sparse. ApoE(-/-) mice with vulnerable (2-kidney, 1-clip renovascular hypertension model) or stable (1-kidney, 1-clip renovascular hypertension model) atherosclerotic plaques were used. Mice were treated with aliskiren (renin inhibitor), irbesartan (angiotensin-receptor blocker), atenolol (beta-blocker), or amlodipine (calcium channel blocker). Atherosclerosis characteristics were assessed. Hemodynamic and hormonal parameters were measured. Aliskiren and irbesartan significantly prevented atherosclerosis progression in 2-kidney, 1-clip mice. Indeed, compared with untreated animals, plaques showed thinner fibrous cap (P&lt;0.05); smaller lipid core (P&lt;0.05); decreased media degeneration, layering, and macrophage content (P&lt;0.05); and increased smooth muscle cell content (P&lt;0.05). Interestingly, aliskiren significantly increased the smooth muscle cell compared with irbesartan. Despite similar blood pressure lowering, only partial plaque stabilization was attained by atenolol and amlodipine. Amlodipine increased plaque smooth muscle cell content (P&lt;0.05), whereas atenolol decreased plaque inflammation (P&lt;0.05). This divergent effect was also observed in 1-kidney, 1-clip mice. Normalizing blood pressure by irbesartan increased the plasma renin concentration (5932+/-1512 ng/mL per hour) more than normalizing it by aliskiren (16085+/-5628 ng/mL per hour). Specific renin-angiotensin system blockade prevents atherosclerosis progression. First, evidence is provided that direct renin inhibition mediates atherosclerotic plaque stabilization. In contrast, beta-blocker and calcium channel blocker treatment only partially stabilize plaques differently influencing atherogenesis. Angiotensin II decisively mediates plaque vulnerability. The plasma renin concentration measurement by an indirect method did not confirm the excessive increase of plasma renin concentration reported in the literature during aliskiren compared with irbesartan or amlodipine treatment.

Tensile strength characteristics of polypropylene composites reinforced with stone groundwood fibers from softwood

The behavior of stone groundwood / polypropylene injection-molded composites was evaluated with and without coupling agent. Stone groundwood (SGW) is a fibrous material commonly prepared in a high yield process and mainly used for papermaking applications. In this work, the use of SGW fibers was explored as a reinforcing element of polypropylene (PP) composites. The surface charge density of the composite components was evaluated, as well as the fiber’s length and diameter inside the composite material. Two mixing extrusion processes were evaluated, and the use of a kinetic mixer, instead of an internal mixer, resulted in longer mean fiber lengths of the reinforcing fibers. On the other hand, the accessibility of surface hydroxyl groups of stone groundwood fibers was improved by treating the fibers with 5% of sodium hydroxide, resulting in a noticeable increase of the tensile strength of the composites, for a similar percentage of coupling agent. A new parameter called Fiber Tensile Strength Factor is defined and used as a baseline for the comparison of the properties of the different composite materials. Finally the competitiveness of stone groundwood / polypropylene / polypropylene-co-maleic anhydride system, which compared favorably to sized glass-fiber / polypropylene GF/PP and glass-fiber / polypropylene / polypropylene-co-maleic anhydride composite formulations, was quantified by means of the fiber tensile strength factor