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1.
Mol Neurobiol ; 57(3): 1502-1515, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31773410

ABSTRACT

Autism spectrum disorders (ASD) comprise a complex of neurodevelopmental disorders caused by a variety of genetic defects and characterized by alterations in social communication and repetitive behavior. Since the mechanisms leading to early neuronal degeneration remain elusive, we chose to examine the properties of NSCs isolated from an animal model of ASD in order to evaluate whether their neurogenic potential may recapitulate the early phases of neurogenesis in the brain of ASD patients. Mutations of the gene coding for the Shank3 protein play a key role in the impairment of brain development and synaptogenesis in ASD patients. Experiments here reported show that NSCs derived from the subventricular zone (SVZ) of adult Shank3Δ11-/- (Shank3-ko) mice retain self-renewal capacity in vitro, but differentiate earlier than wild-type (wt) cells, displaying an evident endosomal/lysosomal and ubiquitin aggregation in astroglial cells together with mitochondrial impairment and inflammasome activation, suggesting that glial degeneration likely contributes to neuronal damage in ASD. These in vitro observations obtained in our disease model are consistent with data in vivo obtained in ASD patients and suggest that Shank3 deficit could affect the late phases of neurogenesis and/or the survival of mature cells rather than NSC self-renewal. This evidence supports Shank3-ko NSCs as a reliable in vitro disease model and suggests the rescue of glial cells as a therapeutic strategy to prevent neuronal degeneration in ASD.


Subject(s)
Autism Spectrum Disorder/genetics , Cell Differentiation/physiology , Microfilament Proteins/genetics , Nerve Tissue Proteins/genetics , Neural Stem Cells/metabolism , Animals , Behavior, Animal/physiology , Disease Models, Animal , Mice , Neurogenesis/physiology , Neuroglia/metabolism , Neurons/metabolism
2.
Photochem Photobiol Sci ; 18(1): 155-165, 2019 Jan 01.
Article in English | MEDLINE | ID: mdl-30375617

ABSTRACT

We prepared water soluble, biocompatible fluorescent turn-on pH nanosensors and characterized their behavior as a function of changes in pH. The response relies on a halochromic reaction of a spirorhodamineamide derived from the bright and highly chemically and photo-stable rhodamine 6G, encapsulated in core/nanoporous shell silica nanoparticles. The fluorescent sensors displayed a fast response in the pH range of intracellular compartments. The encapsulation conferred solubility in aqueous environments and biocompatibility. We assessed the two main properties of the sensor, namely the useful pH range and the kinetics of the response, and compared them to those of the free probe. We found that such properties are strongly dependent on the functionalization and position in the silica matrix relative to the core/shell structure. Finally, we demonstrated the cellular uptake of the nanosensors, and their localization in lysosomes of living cells, by fluorescence confocal microscopy.

3.
Work ; 55(4): 747-756, 2016.
Article in English | MEDLINE | ID: mdl-28059827

ABSTRACT

BACKGROUND: Dairy milking is a demanding work task that has been associated with hand and wrist musculoskeletal disorders. Clinical approaches to identify the early effects of musculoskeletal disorders among dairy parlor workers' wrist have not been well defined. OBJECTIVES: The purpose of this pilot study was to develop a study protocol that would assist in the identification and quantification of hand and wrist disorders among dairy workers that perform tasks in the dairy parlor. Additionally, such a study protocol was needed to perform relatively rapid assessments of the wrist/hand on large samples of dairy workers. METHODS: Fourteen dairy parlor workers were assessed for i) upper limb symptoms and work history through questionnaire, ii) a physical examination of the upper limb and in particular wrists and iii) wrist ultrasonography. An additional 21 unexposed paired participants (the control group) also participated in the data collection. RESULTS: The study results identified two ultrasound acoustic windows characterized by the highest predictive value for alteration of the wrist's structure. Study results indicated an impairment of the distal median nerve in structure and mobility and impairment of the distal tendon of the muscle extensor carpi ulnaris that included dislocation and frank damage. CONCLUSIONS: This study identified at least two acoustic windows that should be assessed with ultrasound studies on larger groups and in prospective periodical health surveillance of dairy workers. The study confirmed the wrist was at risk for biomechanical stress among workers conducting milking tasks in the dairy parlors.


Subject(s)
Cumulative Trauma Disorders/diagnosis , Dairying/methods , Wrist Injuries/diagnosis , Adult , Agricultural Workers' Diseases/epidemiology , Agricultural Workers' Diseases/pathology , Cross-Sectional Studies , Cumulative Trauma Disorders/epidemiology , Humans , Italy/epidemiology , Male , Middle Aged , Pilot Projects , Ultrasonography/methods
4.
J Gastrointest Surg ; 20(2): 361-6, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26489744

ABSTRACT

BACKGROUND: Laparoscopic sleeve gastrectomy (LSG) is associated with serious complications, such as staple line (SL) leaks and bleeding. In order to prevent the occurrence of these complications, surgeons have advocated the need to strengthen the staple line. The aim of this randomized controlled study was to compare the efficacy of three different ways of strengthening of the SL in LSG in preventing surgical post-operative complications. METHODS: Between April 2012 and December 2014, 600 patients (pts) scheduled for LSG were prospectively randomized into groups without SL reinforcement (group A) or with SL reinforcement including fibrin glue coverage (group B), or oversewn SL with imbricating absorbable (Monocryl™; group C) or barbed (V lock®) running suture (group D). Primary endpoints were post-operative leaks, bleeding, and stenosis, while secondary outcomes consisted of the time to perform the staple line reinforcement (SLR) and total operative time. RESULTS: Mean SLR operative time was lower for group B (3.4 ± 1.3 min) compared with that for groups C (26.8 ± 8.5 min) and D (21.1 ± 8.4 min) (p < 0.0001). Mean total operative time was 100.7 ± 16.4 min (group A), 104.4 ± 22.1 min (group B), 126.2 ± 18.9 min (group C), and 124.6 ± 22.8 (group D) (p < 0.0001). Post-operative leaks, bleeding, and stenosis were recorded in 14 pts (2.3 %), 5 pts (0.8 %), and 7 pts (1.1 %), respectively, without statistical difference between the groups. CONCLUSION: Our study suggests that SLR during LSG, with an imbricating or non-imbricating running suture or with fibrin glue, is an unrewarding surgical act with the sole effect of prolonging the operative time.


Subject(s)
Fibrin Tissue Adhesive/therapeutic use , Gastrectomy , Laparoscopy , Obesity, Morbid/surgery , Surgical Stapling/methods , Tissue Adhesives/therapeutic use , Aged , Female , Humans , Male , Middle Aged , Operative Time , Prospective Studies , Sutures , Treatment Outcome
7.
Phys Chem Chem Phys ; 17(15): 10086-92, 2015 Apr 21.
Article in English | MEDLINE | ID: mdl-25788150

ABSTRACT

Sequential adsorption of PdCl4(2-) within weak polyelectrolyte layer-by-layer (LbL) self-assembled multilayer films with further electrochemical reduction to yield Pd(0) nanoparticles (Pd-NPs) has been demonstrated. The electrocatalytic hydrogenation (ECH) of model molecules such as acetophenone and benzophenone on Pd-NPs of different sizes (6 to 35 nm) and bulk Pd crystal surface in hydroalcoholic acid solution has been investigated. Distribution of reaction products (secondary alcohols and alkanes) and faradaic yield was systematically investigated. While the polyelectrolyte multilayers act as nanoreactors by confining PdCl4(2-) ions and preventing the formation of large crystals, their presence also alters the hydrogenation reaction and therefore heat treated surfaces showed only the effect of nanocrystal size on the reaction selectivity and faradaic yield.


Subject(s)
Nanoparticles/chemistry , Palladium/chemistry , Acetophenones/chemistry , Benzophenones/chemistry , Catalysis , Electrochemistry , Hydrogenation , Particle Size , Surface Properties
8.
Kathmandu Univ Med J (KUMJ) ; 12(46): 97-100, 2014.
Article in English | MEDLINE | ID: mdl-25552211

ABSTRACT

BACKGROUND: Endograft dislocation in thoracic aorta has not been widely studied. OBJECTIVES: The purpose of this study is to analyze the incidence and predisposing factor in a single centre experience after 117 procedures. METHOD: Between November 2000 and December 2011, all consecutive patients undergoing endovascular repair for descending thoracic or thoraco-abdominal aortic disease were identified. Follow-up imaging protocol included triple-phase CT-angiography at 1, 4, and 12 months, and annually thereafter. Migration was defined as proximal/ distal movements >10 mm relative to anatomical landmarks or any movement leading to symptoms or reintervention. RESULT: We identified 117 patients. Mean follow-up was 32 months (range, 1-144). Overall, five (4.3%) patients with thoracic EG dislocation were identified. Dislocation was classified as collapse/infolding in 3 cases and migration in 2. Mean delay of the dislocation was 12.7 months. Only one patient developed symptoms and required an additional endograft. In the group of dislocated endografts, mean age (53 ± 20 vs. 68 ± 15, P = .032) and the diameter of the aortic lesion were lower (4.1 cm ± 1.6 vs. 5.6 cm ± 1.8, P = .069), and the proximal landing zone at "zones 2 and 3" were more frequently used (5 vs. 65, P = 0.81). All but one patient with collapse/infolding are still alive and doing well at a mean follow-up of 80 months. CONCLUSION: Dislocation is an infrequent complication, but not so rare. Young age, small aortic diameter , and proximal sealing at the distal arch were the most important data associated with this complication.


Subject(s)
Aortic Aneurysm, Thoracic/surgery , Blood Vessel Prosthesis/adverse effects , Delayed Graft Function/etiology , Endovascular Procedures/methods , Adolescent , Adult , Aged , Aged, 80 and over , Delayed Graft Function/diagnosis , Female , Follow-Up Studies , Humans , Male , Middle Aged , Time Factors , Tomography, X-Ray Computed , Treatment Outcome , Young Adult
9.
Cell Death Dis ; 4: e906, 2013 Nov 07.
Article in English | MEDLINE | ID: mdl-24201805

ABSTRACT

Mucopolysaccharidosis type II (MPSII or Hunter Syndrome) is a lysosomal storage disorder caused by the deficit of iduronate 2-sulfatase (IDS) activity and characterized by progressive systemic and neurological impairment. As the early mechanisms leading to neuronal degeneration remain elusive, we chose to examine the properties of neural stem cells (NSCs) isolated from an animal model of the disease in order to evaluate whether their neurogenic potential could be used to recapitulate the early phases of neurogenesis in the brain of Hunter disease patients. Experiments here reported show that NSCs derived from the subventricular zone (SVZ) of early symptomatic IDS-knockout (IDS-ko) mouse retained self-renewal capacity in vitro, but differentiated earlier than wild-type (wt) cells, displaying an evident lysosomal aggregation in oligodendroglial and astroglial cells. Consistently, the SVZ of IDS-ko mice appeared similar to the wt SVZ, whereas the cortex and striatum presented a disorganized neuronal pattern together with a significant increase of glial apoptotic cells, suggesting that glial degeneration likely precedes neuronal demise. Interestingly, a very similar pattern was observed in the brain cortex of a Hunter patient. These observations both in vitro, in our model, and in vivo suggest that IDS deficit seems to affect the late phases of neurogenesis and/or the survival of mature cells rather than NSC self-renewal. In particular, platelet-derived growth factor receptor-α-positive (PDGFR-α+) glial progenitors appeared reduced in both the IDS-ko NSCs and in the IDS-ko mouse and human Hunter brains, compared with the respective healthy controls. Treatment of mutant NSCs with IDS or PDGF throughout differentiation was able to increase the number of PDGFR-α+ cells and to reduce that of apoptotic cells to levels comparable to wt. This evidence supports IDS-ko NSCs as a reliable in vitro model of the disease, and suggests the rescue of PDGFR-α+ glial cells as a therapeutic strategy to prevent neuronal degeneration.


Subject(s)
Mucopolysaccharidosis II/metabolism , Mucopolysaccharidosis II/pathology , Neural Stem Cells/metabolism , Neural Stem Cells/pathology , Neurodegenerative Diseases/pathology , Neuroglia/metabolism , Neuroglia/pathology , Animals , Apoptosis/genetics , Apoptosis/physiology , Brain/metabolism , Brain/pathology , Cell Differentiation/genetics , Cell Differentiation/physiology , Glycoproteins/deficiency , Glycoproteins/genetics , Glycoproteins/metabolism , Lysosomal Storage Diseases/metabolism , Lysosomal Storage Diseases/pathology , Mice , Mice, Knockout , Mucopolysaccharidosis II/genetics , Neurodegenerative Diseases/metabolism
10.
Curr Med Chem ; 20(20): 2589-600, 2013.
Article in English | MEDLINE | ID: mdl-23627934

ABSTRACT

Mesoporous silica materials (MSM) have been proposed as promising tools for cell specific drug delivery or fluorescent cell tracking. In cancer therapy there is an urgent need to develop a cancer cell specific drug carrier able to limit the non-specific uptake of the drug by normal cells thereby reducing serious side effects. Chemotherapy induced peripheral neurotoxicity (CIPN) is one of the most clinically relevant side effects linked to the use of several antineoplastic drugs. In this study we showed that the uptake of MSM (synthesized using a PEG surfactant-based interfacial synthesis procedure), functionalised with folic acid (MSM-FOL) after 1, 6 and 24 hours is very limited in neuronal-like cellular systems such as differentiated SH-SY5Y human neuroblastoma cells and rat embryonic dorsal root ganglia sensory neurons. By contrast, the nanoparticles are highly internalized in A549 and IGROV-1 cancer cells. The 6 hour-treatment of A549 and IGROV-1 cells with nanoparticles loaded with the antineoplastic drug cisplatin (CP) induced significant cytotoxicity with respect to CP alone. These results were observed treating IGROV-1 cells with 25 and 50 µg/ml nanoparticles doses (corresponding respectively to CP 6.25 and 12.5 µM) and treating A549 with 50 µg/ml.Our results demonstrated a selective uptake of functionalized MSM suggesting them as promising tools for targeted antineoplastic therapy. Further studies will be necessary in order to confirm if this approach may be useful in reducing neurotocity of anticancer drugs.


Subject(s)
Nanoparticles/chemistry , Silicon Dioxide/chemistry , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Cell Survival/drug effects , Cells, Cultured , Cisplatin/chemistry , Cisplatin/pharmacology , Drug Carriers/chemistry , Fluorescein-5-isothiocyanate/chemistry , Folate Receptor 1/genetics , Folate Receptor 1/metabolism , Ganglia, Spinal/cytology , Humans , Microscopy, Confocal , Nanoparticles/toxicity , Neurons/cytology , Neurons/drug effects , Neurons/metabolism , Porosity , Rats , Rats, Sprague-Dawley
11.
Neuroscience ; 172: 12-9, 2011 Jan 13.
Article in English | MEDLINE | ID: mdl-21044661

ABSTRACT

The positive effect of adult undifferentiated mesenchymal stem cells (MSCs) on neuronal survival has already been reported, although the mechanisms by which MSCs exert their effect are still a matter of debate. Here we have demonstrated that MSCs are able to prolong the survival of dorsal root ganglion (DRG) neurons mainly by inhibiting some proteolytic enzymes, and in particular the pathway of metalloproteinases (MMPs), a family of proteins that are involved in many neuronal processes, including survival. The inhibition of MMPs was both direct, by acting on MT-MMP1, and indirect, by acting on those proteins that regulate MMPs' activation, such as Timp-1 and Sparc. The importance of the MMPs' down-regulation for neuronal survival was also demonstrated by using N-isobutyl-N-(4-methoxyphenylsulfonyl)-glycyl hydroxamic acid (NNGH), a wide range inhibitor of metalloproteinases, which was able to increase the survival of DRG neurons in a significant manner. The down-regulation of MMPs, obtained both by MSC contact and by chemical inhibition, led to the inactivation of caspase 3, the executor of apoptotic death in DRG neurons cultured alone, while caspase 7 was found to be irrelevant for the apoptotic process. The capacity of MSCs to prevent apoptosis mainly by inactivating the metalloproteinase pathway is an important finding that sheds light on MSCs' mechanism of action, making undifferentiated MSCs a promising tool for the treatment of many different neurodegenerative pathologies.


Subject(s)
Ganglia, Spinal/enzymology , Mesenchymal Stem Cells/enzymology , Metalloproteases/antagonists & inhibitors , Protease Inhibitors/pharmacology , Sensory Receptor Cells/enzymology , Signal Transduction/physiology , Animals , Apoptosis Regulatory Proteins/physiology , Cell Communication/drug effects , Cell Communication/physiology , Cell Survival/drug effects , Cell Survival/physiology , Cells, Cultured , Coculture Techniques , Female , Ganglia, Spinal/cytology , Ganglia, Spinal/drug effects , Hydroxamic Acids/pharmacology , Mesenchymal Stem Cells/drug effects , Mesenchymal Stem Cells/metabolism , Metalloproteases/physiology , Neural Pathways/drug effects , Neural Pathways/enzymology , Neural Pathways/physiology , Rats , Rats, Sprague-Dawley , Sensory Receptor Cells/cytology , Sensory Receptor Cells/drug effects , Signal Transduction/drug effects , Sulfonamides/pharmacology
12.
J Surg Case Rep ; 2011(4): 3, 2011 Apr 01.
Article in English | MEDLINE | ID: mdl-24950574

ABSTRACT

A gallbladder incarcerated hernia associated with Mirizzi syndrome is a very rare entity and to our knowledge this is the first case ever described in literature. An 85-year-old man presented at the emergency department with a tender right upper quadrant mass. Computed Tomography (CT) revealed the presence of a gallbladder lithiasis with signs of acute cholecystitis, herniated through the abdominal wall with an associated Mirizzi syndrome. Laparoscopic cholecystectomy and repair of the abdominal wall defect were performed. The patient recovered very well and the postoperative period was uneventful.

13.
Exp Neurol ; 226(2): 301-9, 2010 Dec.
Article in English | MEDLINE | ID: mdl-20832406

ABSTRACT

Cisplatin, paclitaxel and bortezomib belong to some of the most effective families of chemotherapy drugs for solid and haematological cancers. Epothilones represent a new family of very promising antitubulin agents. The clinical use of all these drugs is limited by their severe peripheral neurotoxicity. Several in vivo rat models have reproduced the characteristics of the peripheral neurotoxicity of these drugs. However, since only a very limited number of cancer types can be studied in immunocompetent rats, these animal models do not represent an effective way to evaluate, at the same time, the antineoplastic activity and the neurotoxic effects of the anticancer compounds. In this study, we characterized the neurophysiological impairment induced by chronic chemotherapy treatment in BALB/c mice, a strain suitable for assessing the activity of anticancer treatments. At the end of a 4-week period of treatment with cisplatin, paclitaxel, epothilone-B or bortezomib, sensory and sensory/motor nerve conduction velocities (NCV) were determined in the caudal and digital nerves and dorsal root ganglia (DRG) and sciatic nerves were collected for histopathological analysis. The electrophysiological studies revealed that all the compounds caused a statistically significant reduction in the caudal NCV, while impairment of the digital NCV was less severe. This functional damage was confirmed by the histopathological observations evidencing axonal degeneration in the sciatic nerve induced by all the drugs associated with pathological changes in DRG induced only by cisplatin and bortezomib. These results confirm the possibility to use our models to combine the study of the antineoplastic activity of anticancer drugs and of their toxic effects on the peripheral nervous system in the BALB/c mouse strain.


Subject(s)
Antineoplastic Agents/adverse effects , Disease Models, Animal , Peripheral Nervous System Diseases/chemically induced , Peripheral Nervous System Diseases/pathology , Peripheral Nervous System Diseases/physiopathology , Analysis of Variance , Animals , Body Weight/drug effects , Boronic Acids , Bortezomib , Cisplatin , Dose-Response Relationship, Drug , Female , Ganglia, Spinal/drug effects , Ganglia, Spinal/pathology , Ganglia, Spinal/ultrastructure , Mice , Mice, Inbred BALB C , Microscopy, Electron, Transmission/methods , Nerve Fibers, Myelinated/drug effects , Nerve Fibers, Myelinated/pathology , Nerve Fibers, Myelinated/ultrastructure , Neural Conduction/drug effects , Paclitaxel , Peripheral Nervous System Diseases/mortality , Pyrazines , Sciatic Nerve/drug effects , Sciatic Nerve/pathology , Sciatic Nerve/physiopathology , Sciatic Nerve/ultrastructure
15.
Neurosci Lett ; 404(3): 262-5, 2006 Sep 01.
Article in English | MEDLINE | ID: mdl-16814469

ABSTRACT

Vesicular glutamate transporters (VGLUTs) are involved in storing glutamate for secretion at the level of glutamatergic axon terminals, and for this reason they have been extensively used as markers to identify glutamate-releasing cells. Platelets have been considered as a suitable model for studying glutamatergic dysfunction because they perform glutamate uptake and express both external transporters, and NMDA-like receptors. Here, we show that platelets express the pre-synaptic markers VGLUT1 and VGLUT2 and release glutamate following aggregation, implying a possible contributory role in the pathophysiology of stroke, migraine, and other excitotoxic disorders.


Subject(s)
Blood Platelets/metabolism , Glutamic Acid/metabolism , Platelet Aggregation , Vesicular Glutamate Transport Protein 1/biosynthesis , Vesicular Glutamate Transport Protein 2/biosynthesis , Adult , Female , Humans , In Vitro Techniques , Male
16.
J Biomed Mater Res A ; 68(2): 264-72, 2004 Feb 01.
Article in English | MEDLINE | ID: mdl-14704968

ABSTRACT

In elderly and osteoporotic patients an age-related loss of osteoinductivity could be the biological cause of implant failure regardless of the high quality of the implanted device. yttria stabilized tetragonal zirconia (YSTZ), either coated with the bioactive glass named RKKP bioglaze (RKKP) or uncoated, was implanted in the distal femurs of sham-operated and ovariectomized female rats. Animals were sacrificed at 30 and 60 days. Histomorphometry and microhardness tests were performed to assess osteointegration rate as well as bone quality around the implants. Significant decreases (p < 0.0005) in trabecular bone volume, BV/TV (41%), trabecular bone surface BS/TV (33%), trabecular thickness Tb.Th (20%), and trabecular number Tb.N (32%), together with a significant increase in trabecular separation Tb.Sp (184%), were found for the osteopenic rats compared with the sham-operated rats. At both experimental times the RKKP coating ensured a better osteointegration rate with higher AI values than the uncoated YSTZ, even when osteopenic rats were used (48% at 30 days and 12% at 60 days). No differences were observed at the bone-biomaterial interfaces for either material when comparing sham-operated with osteopenic rats. The present results demonstrate that the RKKP bioactive glass used as a coating ensures a high osteointegration rate even in osteoporotic bone, which is already visible from postoperative day 30 and is still apparent on day 60.


Subject(s)
Bone Diseases, Metabolic/therapy , Bone Regeneration/physiology , Bone Substitutes/metabolism , Bone and Bones/metabolism , Coated Materials, Biocompatible , Animals , Bone Diseases, Metabolic/surgery , Glass , Rats , Zirconium
17.
Biomaterials ; 23(18): 3833-41, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12164187

ABSTRACT

Osteointegration of yttria stabilised tetragonal zirconia (YSTZ), either coated with bioactive glass named RKKP bioglaze (RKKP) or uncoated, was evaluated in an animal model. RKKP-coated and uncoated (controls) YSTZ cylinders were implanted in the distal femoral epiphyses of 14 Sprague Dawley rats under general anaesthesia. At the experimental times of 30 and 60 days after sacrifice, histomorphometry and SEM microanalysis were performed on methylmethacrylate-embedded undecalcified sections to determine the osteointegration rate. At 30 days, a significantly higher affinity index was demonstrated in vivo by histomorphometric evaluation in RKKP-coated versus uncoated YSTZ implants p < 0.05); at 60 days, the coated implants behaved better than controls (affinity index of + 32%), but the difference observed lay within the statistical uncertainty. SEM analysis demonstrated better bone adhesion to the material in RKKP-coated YSTZ at both 30 and 60 days. These findings suggest that YSTZ coated with the bioactive glass named RKKP enhances osteointegration of ceramics.


Subject(s)
Biocompatible Materials , Coated Materials, Biocompatible , Femur/metabolism , Glass , Zirconium , Adsorption , Animals , Cell Line , Female , Femur/ultrastructure , Microscopy, Electron, Scanning , Prostheses and Implants , Rats , Rats, Sprague-Dawley , Scattering, Radiation , Time Factors , Tissue Adhesions , Yttrium/metabolism
18.
Eur J Echocardiogr ; 3(1): 13-23, 2002 Mar.
Article in English | MEDLINE | ID: mdl-12067529

ABSTRACT

BACKGROUND: Low flow velocity within the left atrial appendage, as assessed by transoesophageal echocardiography, is a predictor of thromboembolism and of a low success rate of cardioversion of atrial fibrillation. However, the semi-invasive nature does limit its serial application as a screening technique. METHODS AND RESULTS: We investigated the value of transthoracic second harmonic echocardiography and pulsed Doppler at baseline and after intravenous contrast injection to visualize the left atrial appendage and assess blood flow velocities within its cavity. We studied 51 consecutive patients undergoing transoesophageal echocardiography. After transoesophageal echocardiography, transthoracic second harmonic imaging was performed and the left atrial appendage was visualized in 46 patients. Interpretable pulsed Doppler tracings of left atrial appendage flow were obtained at baseline in 39 patients and in 45 patients during Levovist administration. The correlations between peak emptying velocity of left atrial appendage as measured by transoesophageal echocardiography and by transthoracic standard and contrast-enhanced Doppler were 0.81 and 0.91, respectively. The agreement between transoesophageal echocardiography and transthoracic contrast-enhanced pulsed Doppler echocardiography in classifying left atrial appendage flow velocity patterns was 93%. Left atrial appendage thrombus was detected by transthoracic second harmonic imaging in only one of the eight patients shown by transoesophageal echocardiography to have a thrombus. However, all but one of the patients with left atrial appendage thrombus and/or spontaneous echocardiographic contrast at transoesophageal echocardiography had <30cm/s left atrial appendage flow velocity by transthoracic Doppler. CONCLUSIONS: This study shows that left atrial appendage can be visualized by transthoracic second harmonic imaging and that the flow velocity within its cavity is reliably measured by pulsed Doppler in a substantial fraction of patients. Contrast enhancement improves the feasibility and the accuracy of transthoracic evaluation of left atrial appendage flow velocity. The practical value of these results in predicting thromboembolic risk and success of cardioversion of atrial fibrillation needs to be proved by prospective studies.


Subject(s)
Atrial Appendage/diagnostic imaging , Contrast Media , Echocardiography , Aged , Blood Flow Velocity , Echocardiography, Doppler, Pulsed , Echocardiography, Transesophageal , Female , Heart Diseases/diagnostic imaging , Humans , Male , Polysaccharides , Thrombosis/diagnostic imaging
19.
J Biomed Mater Res ; 61(2): 282-9, 2002 Aug.
Article in English | MEDLINE | ID: mdl-12007209

ABSTRACT

The biocompatibility and osseointegration of zirconia (ZrO(2)), either coated with RKKP bioglazeor uncoated, were evaluated in vitro and in vivo. The in vitro test was performed in human osteoblasts, whereas maximal sensitization was performed in 23 Dunkin Hurtley guinea pigs. RKKP bioglaze-coated and uncoated (controls) ZrO(2) cylinders were implanted in the distal femoral epiphyses of 14 Sprague-Dawley rats under general anesthesia, and animals were sacrificed at 30 and 60 days. Lactate dehydrogenase, alkaline phosphatase, and Thiazolyl Blue (MTT) were tested in vitro. A graded score was used for evaluating the results of the sensitization test. Histomorphometry and microhardness testing were performed to quantify the osseointegration rate, as well as bone quality around the implants. Neither in vitro cytotoxicity nor sensitization were observed. Histomorphometry demonstrated that at 30 days, the affinity index was significantly higher in coated implants than in uncoated ones (p < 0.05); at 60 days, the behavior of coated implants was better than that of uncoated ones, but differences were not significant. Significant increases in bone microhardness were found at 1000 microm from the interface area for both uncoated (p < 0.0005) and RKKP bioglaze-coated (p < 0.0005) ZrO(2), and also within 200 microm from the interface (p = 0.014) but only for coated ZrO(2.) These results suggest that RKKP bioglaze-coated ZrO(2) permits biocompatible devices with improved osseointegration properties to be manufactured.


Subject(s)
Coated Materials, Biocompatible/standards , Materials Testing , Osseointegration , Zirconium/standards , Animals , Bone Substitutes/standards , Cell Death/drug effects , Ceramics , Coated Materials, Biocompatible/pharmacology , Coated Materials, Biocompatible/toxicity , Female , Guinea Pigs , Humans , Immunization , Implants, Experimental/standards , Mechanics , Osteoblasts/drug effects , Rats , Survival Rate , Zirconium/pharmacology , Zirconium/toxicity
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