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Biomedical subjects

C Haller

Publications and source records attributed to C Haller.

At least 19 recordsLinked to original sources
PubMed2006

[New treatments in vascular diseases].

In superficial venous insufficiency, surgery remains the treatment of choice. Endovenous therapies are a minimal invasive alternative, whose long-term results are not demonstrated yet. In the treatment of abdominal aortic aneurysm, endovascular repair (EVAR) and laparoscopic approach are comparatively studied with open repair, to define their precise indications. In occlusive arterial disease, endovascular treatment offers inferior results in term of durability and patency, however with a decrease in morbidity and mortality.

Humans↗
PubMed2006

[Quality of life after superficial femoral vein harvest for infra-inguinal reconstructions].

BACKGROUND: The superficial femoral vein (SFV) is a well-established alternative conduit for infra-inguinal reconstructivenous hypertension after SFV harvest may however result in significant morbidity. This study reports the efficiency of SFV as conduit for infra-inguinal reconstructions and characterize the anatomic and physiologic changes in harvest limbs and their relationship to the development of venous complications. METHODS: From May 1999 through November 2003, 23 SFV were harvested from 21 patients undergoing infra-inguinal reconstructions. Bypasses were controlled by regular duplex-ultrasound. The venous morbidity was assessed by measurements of leg circumferences, strain-gauge plethysmography and quality of life, investigated by the VEINES-QOL scale. RESULTS: At a mean follow-up of 10.4 months (range 1-56), primary, secondary patency and limb salvage rates of infra-inguinal bypasses using SFV are 71.4%, 76.2% and 85.7% respectively. No patient had major venous claudication. Oedema was significantly present in nine patients. Strain-gauge plethysmography showed outflow obstruction in all patients. The VEINES-QOL assessment showed no limitation in social and domestic activity, moderate complain about leg heaviness despite presence of oedema. CONCLUSION: The SFV harvest is a reliable conduit for infra-inguinal reconstructions and results in moderate venous morbidity in terms of functional consequences and quality of life.

Aged↗
PubMed2006

Hypoalbuminemia in renal failure: pathogenesis and therapeutic considerations.

Hypoalbuminemia is common in patients with end-stage renal disease (ESRD). It is caused by a combination of a reduced synthesis and an increased degradation of albumin. The altered albumin homeostasis in ESRD patients is caused by a systemic inflammatory state which correlates closely with mortality. Hypoalbuminemia is a strong predictor of an adverse prognosis, but it is not a pathogenic factor in itself. In critically ill patients in intensive care units, the intravenous administration of human serum albumin generally does not improve prognosis. In contrast, in hypoalbuminemic dialysis patients with volume overload and a reduced effective arterial volume the administration of albumin is based on the pathophysiological concept of increasing intravascular oncotic pressure to transfer extravascular fluid into the intravascular compartment for ultrafiltration in order to mobilize edema fluid.

Albumins↗
PubMed2006

[Management of critical limb ischemia].

Critical limb ischemia (CLI) is the leading cause of major leg amputation. Diabetes, smoking and end stage renal disease are the main risk factors for CLI. Despite their reduced survival rate, most CLI patients should be treated by surgical or endovascular arterial reconstruction, since amputation rate with conservative treatment alone is as high as 95% at 1 year in surviving patients with tissue loss, and can be reduced to 25% with successful reconstruction. When arterial reconstruction is impossible or fails, spinal cord stimulation also allows to avoid major amputation in up to 75% of precisely selected patients. Timely management and multidisciplinary approach are advised to reduce the risk of major amputation.

Humans↗
PubMed2006

Contrast-induced nephrotoxicity: clinical landscape.

Over 80 million doses of iodinated intravascular contrast media (CM) were administered in the most recent tabulations of 2003, corresponding to approximately 8 million liters, making it one of the highest volume medical drugs used compared to any other pharmaceutical. The evolution of CM has focused on minimizing adverse events by eliminating ionicity, increasing hydrophilicity, lowering osmolality and increasing the number of iodine atoms per molecule. Contrast media are classified into three general categories based on their osmolality relative to blood: high osmolar (5 times or greater than blood), low osmolar (2-3 times blood) and iso-osmolar (the same as blood). All imaging modalities that employ CM, especially computerized tomography (CT), have shown rapid growth. In the last two decades, the use of CT scanning has increased by 800%. From 1979 to 2002, the number of cardiac catheterization procedures in the USA increased by 390% and in Europe from 1992 to 1999 by 112%. There is a general consensus that renal insufficiency and diabetes are major risk factors for contrast-induced nephropathy (CIN), particularly when co-existing. The US Renal Data System documents a 'relentless' increase in kidney failure, projecting a 90% increase by 2010. Diabetes affects 194 million people worldwide and the number is anticipated to increase by 75% by 2025. The unavoidable conclusion is that patient exposure and prevalence of risk factors for CIN will continue to increase.

Contrast Media↗
PubMed2006

Clinical results of autologous infrainguinal revascularization using grafts originating distal to the femoral bifurcation in patients with mild inflow disease.

AIM: Chronic critical limb ischemia (CLI) often requires venous bypass grafting to distal arterial segments. However, graft patency is influenced by the length and quality of the graft and occasionally patients may have limited suitable veins. We investigated short distal bypass grafting from the superficial femoral or popliteal artery to the infrapopliteal, ankle or foot arteries, despite angiographic alterations of inflow vessels, providing that invasive pressure measurement at the site of the planned proximal anastomosis revealed an inflow-brachial pressure difference of <or=10 mmHg. METHODS: Four hundred and twenty-three consecutive infrainguinal bypass grafts were performed for CLI between June, 1999 and November, 2002 at our institution. All patients underwent preoperative clinical examination, arteriography and assessment of the veins by duplex ultrasound. The study group are patients in whom the proximal and distal anastomoses of the bypass are below the femoral bifurcation and the popliteal artery, respectively. Invasive arterial pressure measurements were recorded at the level of the planned proximal anastomosis which was performed at that level if the difference of the inflow-brachial pressure was <or=10 mmHg, irrespective of angiographic alterations of the inflow vessels proximal to the planned anastomosis. All patients had a clinical follow-up included a duplex examination of their graft, at 1 week, 3, 9 and 12 months and, thereafter, annually. No patient was lost to follow-up. RESULTS: Sixty-seven patients underwent 71 short distal bypass grafts in 71 limbs with reversed saphenous vein grafts in 52, in situ saphenous veins in 11, reversed cephalic vein in 1 and composite veins in 7, respectively. Surgical or endovascular interventions to improve inflow were required in 4 limbs (5.6%). The mean follow-up time was 22.5 months and the two-year survival was 92.5%. Primary and secondary patency rates at 2 years were 73% and 93%, respectively, and the limb salvage rate was 98.5%. CONCLUSION: In appropriately selected patients, short distal venous bypass grafts can be performed with satisfactory patency and limb salvage rates even in the presence of morphologic alterations of the inflow vessels providing that these are not hemodynamically significant, or can be corrected intraoperatively.

Aged↗
PubMed2004

Effect of extracellular hypertonicity and alkalosis on endothelial-derived EA.hy 926 cells in vitro.

Endothelial and local metabolic mechanisms contribute in concert to the regulation of blood flow. In vivo extracellular alkalosis induces a vasoconstriction, hyperosmolarity a vasodilatation. The interaction between local metabolic and endothelial mechanisms is poorly understood. Therefore we investigated in endothelial-derived EA.hy926 cells the secretion of endothelial modulators of vascular tone under hypertonic stress with and without alkalosis: hyperosmolality was generated by either the addition of NaHCO subset 3 (25, 50, 100 mM, pH up to > 8) or mannitol (50, 100, 200 mM) to the cell culture media. The cells were studied using automated cell counting, measurement of the activity of the lactate dehydrogenase (LDH) and a bromo-deoxyuridine (BrdU) cell proliferation assay. Endothelin and cGMP, a surrogate marker for nitric oxide (NO), were measured with specific ELISAs. EA.hy 926 cells formed stable monolayers in vitro. The secretion of endothelin, but not of cGMP was inversely correlated with the osmolality of the incubation media: the endothelin concentration in the supernatants decreased in both mannitol- and NaHCO subset 3 -treated cells in a concentration-dependent manner (152.4 +/- 6.2 pg/ml (control) to 24.4 +/- 2.4 pg/ml (200 mM mannitol), res. to 18.2 +/- 2.7 pg/ml (100 mM NaHCO subset 3). Neither hypertonic bicarbonate nor mannitol solutions decreased the monolayer cell density or cell viability during the 6 hour incubation period. In conclusion, EA.hy926 cells are quite resistant against a 6-hour hypertonic/alkaline stress. Hypertonicity decreases the secretion of endothelin and has no effect on cGMP. At each level of hypertonicity the endothelin concentration was similar in the NaHCO subset 3 and mannitol media arguing against a direct role of endothelin in alkalosis-induced vasoconstriction in vivo. The decreased secretion of endothelin during hypertonicity could contribute to the hyperosmolal vasodilation seen in vivo.

Alkalosis↗
PubMed2004

Acute sialadenitis after percutaneous coronary intervention.

A 63 year old woman developed a swelling of the submandibular glands following PTCA. An ENT specialist made the presumptive diagnosis of viral sialadenitis. The submandibular swelling subsided completely within 48 hours. Sialadenitis is a rare side effect of ionic and nonionic radiocontrast agents. The pathogenic mechanism is not known. The swelling is self-limited with an excellent prognosis without specific therapy.

Angioplasty, Balloon, Coronary↗
PubMed2004

Vacuum-assisted conservative treatment for the management and salvage of exposed prosthetic hemodialysis access.

Recurrent puncture of dialysis grafts can cause erosion and ulcer formation in the skin over the prosthetic material. Contamination of the wound can lead to infection of the graft, and the necessity to remove it. We describe four cases where agressive treatment with debridement, intravenous antibiotics and negative pressure therapy allowed prosthesis salvage without discontinuation of hemodialysis.

Aged↗
PubMed2004

[Lung volume reduction surgery for emphysema: a unilateral or bilateral approach?].

INTRODUCTION: Lung Volume reduction surgery (LVRS) is a recognized therapeutic option for patients presenting with severe and disabling pulmonary emphysema. Case selection is based upon clinical, morphological and functional criteria. STATE OF THE ART: LVRS has shown promising results, with improvements in exercise capacity, pulmonary function and quality of life, in selected patients with severe and disabling emphysema. A variety of surgical techniques have been described. The procedure may be unilateral or bilateral, through a sternotomy or by a video-assisted thoracoscopic (VATS) technique. The controversial aspects of the surgical technique will be analysed and discussed in the following review. PERSPECTIVES: A bilateral approach clearly offers a better functional improvement when compared to a unilateral procedure, however, the postoperative functional decline appears greater and more rapid after a bilateral procedure. A unilateral approach, with often less postoperative morbidity, allows the option to perform a future contra-lateral procedure in the event of further clinical or functional deterioration. CONCLUSIONS: In selected cases LVRS is an effective treatment for severe pulmonary emphysema. Different surgical techniques have been described. Nowadays VATS is considered to be the technique of choice, with the option to carry out a future unilateral or bilateral procedure.

Humans↗
PubMed2003

Mitral valve endocarditis: an uncommon cause of myocardial infarction.

A 39 year old woman presented with acute anterior myocardial infarction. At coronary angiography the distal left anterior descending coronary artery (LAD)was occluded despite otherwise normal coronary arteries. The LAD was successfully recanalized using PTCA. Subsequently, a transesophageal echocardiogram revealed vegetations and a significant incompetence of the mitral valve. Blood cultures identified out enterococcus faecalis. Despite intra-venous antibiotic treatment guided by sensitivity testing, the patient ultimately required elective mitral valve replacement. During a prior outpatient diagnostic work-up of fever/malaise, the diagnosis of infective endocarditis was not made.This case conveys two main messages: 1) because the history and physical sings of bacterial endocarditis can be subtle or non-specific, the first step to diagnose infective endocarditis is to include it in the differential diagnosis. 2) Percutaneous coronary intervention is an effective treatment of septic embolic occlusion of a major coronary artery.

Adult↗
PubMed2003

[Intestinal barotrauma after diving--mechanical ileus in incarceration of the last loop of the small intestine between a mobile cecum and sigmoid].

A few hours after a self-contained underwater breathing apparatus (SCUBA) dive at 30 meters depth, a 49 years-old man complained of diffuse abdominal pain with nausea and vomitus. A laparotomy was performed 36 hours after a conservative treatment because of persistent mechanical small bowel obstruction. The last ileal loop was strangulated between a mobile ceacum and a long sigmoid loop. The man never had previous abdominal surgery. In absence of intestinal necrosis, a caecopexy was done and there was no post-operative complications. The gas distension during the ascension following the Boyle-Mariotte law and its distribution induced in this man with a special anatomy a mechanical small bowel obstruction. The treatment of mobile caecum and the literature of abdominal barotrauma is reviewed.

Barotrauma↗
PubMed2001

Thymus medulla consisting of epithelial islets each derived from a single progenitor.

The thymus is organized into medullary and cortical zones that support distinct stages of T-cell development. The formation of medulla and cortex compartments is thought to occur through invagination of an endodermal epithelial sheet into an ectodermal one at the third pharyngeal pouch and cleft, respectively. Epithelial stem/progenitor cells have been proposed to be involved in thymus development, but evidence for their existence has been elusive. We have constructed chimaeric mice by injecting embryonic stem (ES) cells into blastocysts using ES cells and blastocysts differing in their major histocompatibility complex (MHC) type. Here we show that the MHC class-II-positive medullary epithelium in these chimaeras is composed of cell clusters, most of which derive from either embryonic stem cell or blastocyst, but not mixed, origin. Thus, the medulla comprises individual epithelial 'islets' each arising from a single progenitor. One thymic lobe has about 300 medullary areas that originate from as few as 900 progenitors. Islet formation can be recapitulated after implantation of 'reaggregated fetal thymic organs' into mice, which shows that medullary 'stem' cells retain their potential until at least day 16.5 in fetal development. Thus, medulla-cortex compartmentalization is established by formation of medullary islets from single progenitors.

Animals↗
PubMed2001

Differential effects of radiocontrast agents on human umbilical vein endothelial cells: cytotoxicity and modulators of thrombogenicity.

UNLABELLED: The endothelium plays a central role in the regulation of blood flow and coagulation. The impact of radiocontrast agents on endothelial cells is therefore potentially clinically important, particularly in percutaneous interventions for acute coronary thrombosis. The effects of radiocontrast agents on endothelial cell viability and determinants of thrombogenicity were studied in human umbilical vein endothelial cells (HUVECs) in vitro. Intercellular tight junctions were assessed using immunofluorescence microscopy and measurement of the transmonolayer electrical resistance (TMR). The concentrations of endothelin-1 (E), von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1) and thrombomodulin (T) were measured in the cell culture media. The ionic, high osmolal radiocontrast agent diatrizoate induced concentration-dependent cell death and an opening of tight junctions with the attendant abolition of the TMR. The concentration of E decreased, vWF increased in the cell culture media, the concentration of PAI-1 and T was not significantly changed by diatrizoate. Radiocontrast agents with reduced osmolality (ioxaglate: ionic; iopamidol: non-ionic) induced an increase in PAI-1 and vWF, but E and T were not significantly changed. CONCLUSIONS: Radiocontrast agents have differential effects on endothelial cells in vitro including the secretion of modulators of thrombogenesis. The effects are most pronounced in the markedly hyperosmolal compound diatrizoate suggesting a contributory role of hypertonicity. Ioxaglate and iopamidol both increased the prothrombotic factors vWF and PAI-1 to the same degree indicating a similar risk of thrombogenicity between low-osmolal ionic and non-ionic radiocontrast agents in this in vitro model.

Blood Coagulation↗
PubMed2001

Essential requirement for c-kit and common gamma chain in thymocyte development cannot be overruled by enforced expression of Bcl-2.

The thymus in mice lacking both the receptor tyrosine kinase c-kit and the common cytokine receptor gamma chain (gamma(c)) is alymphoid because these receptors provide essential signals at the earliest stages of thymocyte development. The signals transduced by these receptors potentially regulate proliferation, survival, or differentiation, but the contribution of each receptor to distinct intracellular signaling cascades is only poorly defined. Here, we have examined whether enforced expression of Bcl-2 can rescue thymocyte development in c-kit and gamma(c) single or double mutant mice. A bcl-2 transgene (E(mu)-bcl-2-25; expressed in the T cell lineage) was introduced into (a) c-kit and gamma(c) wild-type (c-kit+gamma(c)+bcl+), (b) c-kit-deficient (c-kit(-)gamma(c)+bcl+), (c) gamma(c)-deficient (c-kit+gamma(c)-bcl+), or (d) c-kit and gamma(c) double-deficient mice (c-kit-gamma(c)-bcl+). The bcl-2 transgene was functionally active in wild-type and c-kit or gamma(c) single mutants, as it promoted survival of ex vivo isolated thymocytes, including pro-T cells. In vivo, however, transgenic Bcl-2 did not release T cell precursors from their phenotypic block and failed to increase progenitor or total thymocyte cellularity in c-kit or gamma(c) single or double mutants. These data argue strongly against a role for Bcl-2 as a key mediator in signaling pathways linked to cytokine and growth factor receptors driving early thymocyte development.

Animals↗
PubMed2001

A perspective on inflammatory bowel disease in the child and adolescent at the turn of the millennium.

The literature of the past year has produced significant advances relevant to the diagnosis and treatment of children and adolescents with inflammatory bowel disease. This review focuses on new observations regarding the epidemiology, genetics, etiology, diagnosis, and treatment of both Crohn's disease and ulcerative colitis in children. Particular attention is paid to the expanded indications for the use of immunomodulatory therapy, and to the early published data regarding the safety and efficacy of treatment with infliximab.

Adolescent↗
PubMed2000

Influence of intercellular junctions on endothelin secretion of human umbilical vein endothelial cells in vitro.

The endothelium plays a pivotal role in the rheological regulation of blood flow by the secretion of vasoactive factors. The interaction between shear forces and the endothelium is determined by the mechanical properties of the endothelial cell layer which are associated with intercellular junctions. Cell-cell contacts could therefore modulate the secretion of vasocative factors in response to rheological stimuli. We investigated the relationship between intercellular junctions and the secretion of the vasoconstrictor peptide endothelin and the coagulation co-factor von Willebrand factor (vWF). Human umbilical vein endothelial cells (HUVECs) were used as in vitro endothelial model system. Intercellular junctions were reversibly disrupted by calcium chelation or hypertonic stress; alternatively, the formation of intercellular junctions was inhibited by culturing the cells in suspension or by plating them in the presence of an inhibitory anti-VE-cadherin antibody. The opening of intercellular junctions was verified by assessing transmonolayer electrical resistance (TMR) and immunofluorescence morphology. The concentration of endothelin and vWF was measured in the cell culture supernatants using specific ELISAs. The secretion of endothelin was inhibited by EGTA (5 mM) and stimulated by incubation with tumor necrosis factor alpha (TNFalpha, 40 ng/ml). Treatment with hypertonic medium (glycerol, 1,200 mosmol/l) for 10 minutes opened intercellular junctions and markedly reduced the secretion of endothelin. HUVECs in suspension culture did not secrete endothelin and failed to respond to TNFalpha, but readily resumed these functions upon forming a new monolayer on plastic. The reconstitution of intercellular junctions after suspension culture could be inhibited using a specific anti-VE-cadherin antibody. This antibody, but not a non-specific anti-human-IgG antibody reduced endothelin secretion. The secretion of von Willebrand Factor was less dependent on intercellular junctions. The opening of intercellular junctions did not induce cell death, since the cells continued to exclude trypan blue. The results of this study suggest a novel and potentially pathophysiologically/clinically relevant correlation between intercellular junctions and the secretion of endothelin in endothelial cells.

Cadherins↗