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OBJECTIVE: Cardiovascular disease (CVD) and cerebrovascular disease are the leading cause of death around the world all the time. A novel marker described as the stress hyperglycemia ratio (SHR) can reflect the acute hyperglycemic status and is associated with poor outcomes in patients with acute illness, such as stroke and myocardial infarction (MI). Our previous study has shown that SHR was strongly related to the clinical outcomes of stroke patients. Nevertheless, the association between SHR and clinical outcomes in patients with CVD is still unclear and controversial. Consequently, in the current study, we analyzed the association of SHR and clinical outcomes in CVD patients by systematic review and meta-analysis. MATERIALS AND METHODS: We searched the electronic databases to identify SHR studies of patients who met the eligibility criteria for CVD. We performed our study complying with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We utilized a ten terms tool to assess the potential bias of included studies. Major adverse cardiovascular and cerebrovascular events (MACCEs), all-cause death, left ventricular ejection fraction (LVEF), and other exciting outcome data were extracted for statistical analysis. Moreover, we used the DerSimonian and Laird random-effects model to perform the meta-analysis and conducted subgroup analyses to identify factors associated with substantial heterogeneity. RESULTS: The study cohort included nine studies comprising 32,292 patients with CVD. Our meta-analysis found that MACCEs in the high SHR group were 1.68 folds compared with that in the low SHR group [odds ratio (OR) 1.68, 95% confidence interval (CI) 1.41-2.00, p < 0.00001]. Besides, all-cause death in the high SHR group was 1.52 folds compared with that in the low SHR group (OR 1.52, 95% CI 1.15-2.01, p < 0.00001). Higher SHR meant the lower LVEF (mean difference [MD] -2.03, 95% CI [-3.28-0.79], p = 0.001). The risk of cardiogenic shock and stroke were 2.47 and 1.53 folds in the high SHR group, respectively, compared with the low SHR group. Yet, no statistically significant difference was observed for revascularization (OR 0.88, 95% CI 0.77-1.01, p = 0.08), recurrent MI (OR 1.27, 95% CI 0.69-2.33, p = 0.44), and left ventricular end-diastolic diameter (LVEDD) (MD 0.61, 95% CI [-1.65, 2.87], p = 0.60) between the two groups. Subgroup analyses identified that different study design was associated with heterogeneity about MACCEs and LVEF. Besides, studies from different countries were associated with heterogeneity about all-cause death. CONCLUSIONS: Higher SHR significantly increases the occurrence of MACCEs and all-cause death and decreases LVEF. Moreover, Higher SHR means a higher risk of cardiogenic shock and stroke. Nevertheless, SHR had no relationship with revascularization, recurrent MI, and LVEDD. As a novel and non-invasive marker, SHR should be paid more attention to in clinical practice. Future investigation should focus on the diagnostic value of SHR in CVD and the early control of stress hyperglycemia. Although no randomized, double-blind studies have been conducted, the available massive sample studies reflect the actual situation in the clinic and assist clinical decision-making.
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Doenças Cardiovasculares , Acidente Vascular Cerebral , Humanos , Volume Sistólico , Choque Cardiogênico , Função Ventricular Esquerda , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
Polyphenols can trigger immunity that activates intracellular anti-inflammatory signaling and prevents external infections. In this study, we report the fabrication of chitosan-based hydrogels with epigallocatechin gallate (EGCG) using enzyme-mediated one-pot synthesis. The tyrosinase-mediated oxidative reaction of the phenolic rings of EGCG with the primary amines on chitosan results in stable EGCG-chitosan hydrogels. The EGCG concentrations contributed to the cross-linking density and physical properties of EGCG-chitosan hydrogels. Furthermore, EGCG-chitosan hydrogels maintained intrinsic properties such as antibacterial and antioxidant effects. When endotoxin-activated RAW 264.7 macrophage cells were cultured with EGCG-chitosan hydrogels, the hydrogels reduced the inflammatory response of the RAW 264.7 cells. Furthermore, subcutaneous implantation of EGCG-chitosan hydrogels reduced endogenous macrophage and monocyte activation. When the EGCG-chitosan hydrogels were applied to a full-skin defect wound, they facilitated skin regeneration. Our study demonstrates that the one-pot synthesized EGCG-chitosan hydrogels can be applied in broad tissue regeneration applications that require immune modulation.
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Objective: To explore the efficacy and safety of polyethylene glycal recombinant human granulocyte colony-stimulating factor (PEG-rhG-CSF) in preventing chemotherapy-induced neutropenia in patiens with breast cancer. Methods: There were two parts in the present phase â £ clinical study. One was a randomized, controlled clinical study. Patients in this study received PEG-rhG-CSF or rhG-CSF in the first cycle and followed with both PEG-rhG-CSF in the rest of 3 cycles. The other one was a single arm study. Patients who developed â ¢/â £ grade neutropenia in the screening cycle received PEG-rhG-CSF in the rest of 3 cycles chemotherapy. Results: In the first cycle of randomized, controlled study, the incidence of â £ grade neutropenia are 31.48% and 35.58% respectively in PEG-rhG-CSF and rhG-CSF group, with no statistically significant differences (P=0.527 6). The duration of â £ grade neutropenia respectively are 2.22±1.58 and 3.00±1.59 days, with a statistically significant difference (P=0.016 6). In the single arm study, the incidence of â £ grade neutropenia was 57.76% in screening cycle. And the incidence decreased to 16.35%, 10%, and 8.57% in the followed 3 cycle after the use of PEG-rhG-CSF. The incidence of adverse effects was 5.06%, and the major adverse effect was bone pain which with an incidence of 2.8%. Conclusion: The fixed 6mg dose of PEG-rhG-CSF can effectively prevent neutropenia in patients with breast cancer in multicycle chemotherapy and it has a low incidence of adverse events and mild adverse reaction.
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Neutropenia/induzido quimicamente , Neoplasias da Mama , Fator Estimulador de Colônias de Granulócitos , Humanos , Neoplasias Pulmonares , Polietileno , Proteínas RecombinantesRESUMO
In2O3 thin films were prepared on c-plane sapphire substrates using laser molecular beam epitaxy technique. The X-ray diffraction (XRD) patterns revealed that the In2O3 thin films were highly oriented along the (111) direction. The intensity of (222) diffraction peaks mainly depend on growth temperature, and the crystallite sizes mainly depend on oxygen pressure. The carrier concentrations exhibit a decrease with increasing growth temperature and oxygen pressure, meantime, the resistivity increase. The red shift of In2O3 thin films respect to that of bulk In2O3 can be explained by defect energy levels formation, the blue shift of In2O3 thin films depends on carrier concentration, can be explained by Burstein-Moss band-filling effect.
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A compact advanced extreme-ultraviolet (EUV) spectrometer operating in the EUV wavelength range of a few nanometers to measure spatially resolved line emissions from tungsten (W) was developed for studying W transport in fusion plasmas. This system consists of two perpendicularly crossed slits-an entrance aperture and a space-resolved slit-inside a chamber operating as a pinhole, which enables the system to obtain a spatial distribution of line emissions. Moreover, a so-called v-shaped slit was devised to manage the aperture size for measuring the spatial resolution of the system caused by the finite width of the pinhole. A back-illuminated charge-coupled device was used as a detector with 2048 × 512 active pixels, each with dimensions of 13.5 × 13.5 µm2. After the alignment and installation on Korea superconducting tokamak advanced research, the preliminary results were obtained during the 2016 campaign. Several well-known carbon atomic lines in the 2-7 nm range originating from intrinsic carbon impurities were observed and used for wavelength calibration. Further, the time behavior of their spatial distributions is presented.
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The ITER vacuum ultra-violet (VUV) core survey spectrometer has been designed as a 5-channel spectral system so that the high spectral resolving power of 200-500 could be achieved in the wavelength range of 2.4-160 nm. To verify the design of the ITER VUV core survey spectrometer, a two-channel prototype spectrometer was developed. As a subsequent step of the prototype test, the prototype VUV spectrometer has been operated at KSTAR since the 2012 experimental campaign. From impurity injection experiments in the years 2015 and 2016, strong emission lines, such as Kr xxv 15.8 nm, Kr xxvi 17.9 nm, Ne vii 46.5 nm, Ne vi 40.2 nm, and an array of largely unresolved tungsten lines (14-32 nm) could be measured successfully, showing the typical photon number of 1013-1015 photons/cm2 s.
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Volume-produced negative ion source still requires enhancement of current density with lower input RF (radio-frequency) power in lower operating pressure for various applications. To confirm recent observation of efficient negative ion production with a short cylindrical chamber with smaller effective plasma size, the RF-driven transformer-coupled plasma H(-) ion source at Seoul National University is modified by adopting a newly designed quartz RF window to reduce the chamber length. Experiments with the reduced chamber length show a few times enhancement of H(-) ion beam current compared to that extracted from the previous chamber design, which is consistent with the measured H(-) ion population. Nevertheless, decrease in H(-) ion beam current observed in low pressure regime below â¼5 mTorr owing to insufficient filtering of high energy electrons in the extraction region needs to be resolved to address the usefulness of electron temperature control by the change of geometrical configuration of the discharge chamber. A new discharge chamber with conically converging configuration has been developed, in which the chamber diameter decreases as approaching to the extraction region away from the planar RF antenna such that stronger filter magnetic field can be utilized to prohibit high energy electrons from transporting to the extraction region. First experimental results for the H(-) ion beam extraction with this configuration show that higher magnetic filter field makes peak negative beam currents happen in lower operating pressure. However, overall decrease in H(-) ion beam current due to the change of chamber geometry still requires further study of geometrical effect on particle transport and optimization of magnetic field in this novel configuration.
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CdSe0.75S0.25 semiconductor nanocrystals were synthesized by chemical colloidal route. The crystal structure, morphology and optical properties of synthesized CdSe0.75S0.25 nanocrystals were characterized by XRD, TEM and UV-Vis absorption spectroscopy respectively. The crystal structure of CdSe0.75S0.25 is face-centered Cubic sphalerite phase. The average size is about 7 nm in diameter. A gold tip-to-tip structure electrode with the gap size -20 microm was fabricated using conventional optical lithography technique followed by film deposition and standard lift-off process. An optoelectronics device was fabricated based on CdSe0.75S0.25 by assembling nanocrystals into electrodes by using dielectrophoresis (DEP) process. The electrical transport properties and opto-electrical transport properties of the fabricated device were measured at temperature range from 5 K to 305 K. The results show that the resistance of CdSe0.75S0.25 NCs increases with the temperature decreases, indicating a typical semiconductor behavior. An obvious photoconductive behavior was observed, demonstrated potential application in nano-optoelectronics devices. After data analyzing, the conductivity shows the 0.5 exponent of Efros-Shklovskii variable-range-hopping (ES-VRH) model.
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Although the prophylaxis in controlling sterility within the operating room environment has been greatly improved, implant-associated infection is still one of the most serious complications in implant surgeries due to the existence of immune depression in the peri-implant area. The antibacterial ability of materials themselves logically becomes an important factor in preventing implant-associated infections. With the understanding of the pathogenesis of implant-associated infections, many approaches have been developed through providing an anti-adhesive surface, delivering antibacterial agents to disrupt cell-cell communication and preventing bacteria aggregation or biofilm formation, or killing bacteria directly (lysing the cell membrane). In this article, we review the current strategies in improving the antibacterial ability of materials to prevent implant infection and further present promising tactics in materials design and applications.
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Antibacterianos/uso terapêutico , Infecções Bacterianas/prevenção & controle , Materiais Biocompatíveis/uso terapêutico , Controle de Infecções , Desenho de Prótese , Infecções Relacionadas à Prótese/prevenção & controle , Antibacterianos/química , Infecções Bacterianas/microbiologia , Materiais Biocompatíveis/química , Quitosana/uso terapêutico , Preparações de Ação Retardada , Humanos , Infecções Relacionadas à Prótese/microbiologia , Propriedades de SuperfícieRESUMO
In recent years, a variety of new technologies have been proposed that allow rapid qualitative and quantitative microbiological analyses. In this paper we discuss the urgent needs for reliable and rapid microbiological analytical techniques in different applicative fields involving the research, production and medical application of implant materials, and the potential benefits derived from the use of new methods for rapid bacterial quantification. Current compendial methods are easy to perform and have gained confidence over their long period of use, but the supplemental use of new technologies could represent real breakthroughs whenever sensitive and rapid responses are urgently required and not met by the tests currently in use. Overall, the new microbiological methods require critical evaluation depending on their specific type of application and they may still not be thought of as totally substitutive, but they certainly exhibit considerable potential for different areas of biomaterials, as well as for advanced therapy medicinal and tissue engineering treatments.
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Materiais Biocompatíveis/química , Teste de Materiais , Técnicas Microbiológicas , Técnicas de Diagnóstico Molecular , Próteses e Implantes/microbiologia , Desenho de Prótese , Infecções Relacionadas à Prótese/microbiologia , Materiais Biocompatíveis/uso terapêutico , Humanos , Infecções Relacionadas à Prótese/diagnóstico , Infecções Relacionadas à Prótese/prevenção & controle , Reprodutibilidade dos Testes , Propriedades de Superfície , Engenharia TecidualRESUMO
Several species belonging to Staphylococcus genus (non Sau/ non Sep species) exhibit increasing abilities as opportunistic pathogens in colonisation of periprosthesis tissues. Here we report on antibiotic resistance of 193 strains, belonging to non Sau/ non Sep species, consecutively collected from orthopedic implant infections in a period of about 40 months. The 193 strains (representing 17% of all staphylococci isolated) were analysed for their antibiotic resistance to 16 different drugs. Five species turned out more prevalent, ranging from 1 to 5%: S. hominis (4.2%), S. haemolyticus (3.7%), S. capitis (2.7%), S. warneri (2.6%), and S. cohnii (1.6%). Among these, the prevalence of antibiotic resistance to penicillins was similar, ranging from 51% to 66%. Conversely, significant differences were observed for all the remaining antibiotics. For S. haemolyticus the resistances to oxacillin and imipenem, the four aminoglycosides and erythromycin were at least twice that of the other three species which were compared. S. warneri was on the contrary the species with the lowest occurrence of resistant strains. Ten species appeared only rarely at the infection sites: S. lugdunensis, S. caprae, S. equorum, S. intermedius, S. xylosus, S. simulans, S. saprophyticus, S. pasteuri, S. sciuri, and S. schleiferi. The behaviours of these species, often resistant to penicillins, were individually analysed. Differences in both the frequencies and the panels of antibiotic resistances observed among the non Sau/ non Sep species: i) suggest that horizontal spreading of resistance factors, if acting, was not sufficient per se to level their bio-diversities; ii) highlight and confirm the worrisome appearance within the Staphylococcus genus of emerging ""new pathogens"", not homogeneous for their virulence and antibiotic resistance prevalence, which deserve to be recognised and treated individually.
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Ortopedia , Prevalência , Próteses e Implantes/microbiologia , Infecções Estafilocócicas/epidemiologia , Staphylococcus/efeitos dos fármacos , Humanos , Especificidade da Espécie , Staphylococcus/classificação , Staphylococcus/genética , Staphylococcus/isolamento & purificaçãoRESUMO
There are numerous reports in the literature using animal models of osteomyelitis for investigating pathogenesis, diagnosis, and treatment of bone infections. Rabbits, rats, and dogs are commonly used animals, and, less frequently, chickens, guinea pigs, miniature pigs, goats, and sheep. Commonly used bones for creating local osteomyelitis include tibia, femur, and radius, and, less frequently, mandible and spine. When designing a specific model, one should consider which animal and which bone will be used, which route for inoculation (either local injection or systemically through vascular injection), which bacterial species and how many bacteria should be applied, if and what sclerosing agent, foreign body or implant should be employed, and if local trauma is needed. Basic methods of evaluation include clinical observation, radiography, microbiology, and histology.
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Modelos Animais de Doenças , Osteomielite/patologia , Animais , Osteomielite/microbiologiaRESUMO
Several species belonging to Staphylococcus genus, other than Staphylococcus aureus and Staphylococcus epidermidis (non Sau/ non Sep species), exhibit increasing abilities as opportunistic pathogens in the colonisation of periprosthetic tissues. Consequently, the availability of means for accurate identification is crucial to assess the pathogenic characteristics and to clarify clinical relevance of the individual species. Here, 146 clinical staphylococcal isolates belonging to non Sau/ non Sep species from prosthesis-associated orthopedic infections were analyzed by conventional enzymatic galleries and by automated ribotyping. Twelve different species were recognised: S. capitis, S. caprae, S. cohnii, S. equorum, S. haemolyticus, S. hominis, S. lugdunensis, S. pasteuri, S. sciuri, S. simulans, S. warneri, S. xylosus. Ribotype identifications were compared with the phenotypes obtained by the Api 20 Staph system and/or ID 32 Staph system. ID 32 Staph profiles were more consistent with ribotyping results than Api Staph profiles. Across the different staphylococcal species investigated, correct identifications with Api Staph were 45%, while with ID 32 Staph they were 59%. It has, however, to be mentioned that ID 32 Staph was mostly applied to discriminate unmatched ribotyping and Api Staph identifications, thus to a subpopulation of strains with ""atypical"" metabolic profile. Automated ribotyping provided a correct identification for 91% of the isolates. These results confirm automated ribotyping as a convenient rapid technique, still subject to improvements, which will accurately and rapidly recognise the newly emerging staphylococcal pathogens in implant-related orthopedic infections.
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Automação , Equipamentos Ortopédicos/microbiologia , Ribotipagem , Infecções Estafilocócicas/microbiologia , Staphylococcus/isolamento & purificação , Humanos , Especificidade da Espécie , Infecções Estafilocócicas/diagnóstico , Staphylococcus/classificação , Staphylococcus/genéticaRESUMO
Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant.
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Materiais Biocompatíveis/química , Dióxido de Carbono/farmacologia , Próteses e Implantes , Esterilização , Titânio/química , Ligas/química , Animais , Materiais Biocompatíveis/análise , Teste de Materiais , Modelos Animais , Ratos , Ratos Sprague-Dawley , Esterilização/métodos , Propriedades de Superfície , Titânio/análiseRESUMO
In spite of the recent achievements derived from modern protocols of prophylaxis, orthopedic surgical infections still remain unacceptably frequent, especially in light of the often devastating outcomes of septic complications. The spectrum and the prevalence of the bacteria most frequently involved in orthopedic infections are here explored, with particular reference to those infections associated to implant biomaterials, which were grouped based on device typology. During a 30 months period (from September 2000 to April 2003), 1027 microbial strains were consecutively isolated from 699 patients undergoing revision surgery at the Rizzoli Orthopedic Institute. 775 (75.5%) of all these microorganisms were identified as belonging to the Staphylococcus genus, 82 (8%) to the Enterobacteriaceae family, 75 (7.3%) to the Pseudomonas genus, 54 (5.3%) to the Enterococcus genus and 20 (1.9%) to the Streptococcus genus. While confirming the importance of staphylococci as the most diffuse cause of infection, our data indicate an unexpectedly high prevalence of S. epidermidis on infected hip and knee arthroprostheses, respectively of 42% and 44%. The spectrum of bacteria infecting either internal or external fracture fixation devices appears to differ from that of hip and knee arthroprostheses and more closely resembles that of infections non-associated to medical devices, being characterized by a relatively higher prevalence of Staphylococcus aureus (over 40%) and Pseudomonas aeruginosa. Enterobacteriaceae and members of the Streptococcus and Corynebacterium genera are frequently associated with implants in which surgical incisions were made near the perineum, determining a completely altered spectrum.
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Infecções Bacterianas/epidemiologia , Procedimentos Ortopédicos/efeitos adversos , Infecções Relacionadas à Prótese/microbiologia , Bactérias Gram-Negativas/isolamento & purificação , Bactérias Gram-Positivas/isolamento & purificação , Humanos , Itália/epidemiologia , Infecções Relacionadas à Prótese/epidemiologiaRESUMO
Implant infection is an aggressive, often irreducible post-surgical infection. It remains the primary cause of implant failure. Bacterial contamination during surgery and subsequent adhesion onto biomaterial surface of opportunistic microorganisms, such as staphylococcal species, exopolysaccharidic slimes or specific adhesins, initiates the implant infection. Pathogenesis of periprosthestic infection is the focus of studies aimed at developing infection resistant materials.
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Materiais Revestidos Biocompatíveis/uso terapêutico , Infecções Relacionadas à Prótese/microbiologia , Infecções Relacionadas à Prótese/prevenção & controle , Doença Aguda , Adesinas Bacterianas/metabolismo , Biofilmes , Doença Crônica , Materiais Revestidos Biocompatíveis/química , Farmacorresistência Bacteriana , Humanos , Infecções Relacionadas à Prótese/fisiopatologia , Fatores de RiscoRESUMO
This article concisely reviews the effects of sterilization on the mechanical properties and surface chemistries of implantable biomaterials. This article also summarizes the biological effects of the sterilization-related changes in the implant. Because there are so many different types of implant materials currently in use (including metals, polymers, and diverse biological materials), the response of tissue to these different materials varies dramatically. This review further discusses the effects of sterilization on in vivo and in vitro tissue response specifically to implantable metals and polyethylene, with the possibility of future biocompatibility testing of the implants sterilized with supercritical phase carbon dioxide sterilization.
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Materiais Biocompatíveis/química , Próteses e Implantes , Infecções Relacionadas à Prótese/prevenção & controle , Esterilização/métodos , Humanos , Falha de Prótese , Propriedades de SuperfícieRESUMO
In the last decade the rising phenomenon of resistance to most common antibiotic drugs among staphylococcal clinical isolates has been a reason for serious concern and alarm. The present study investigated the prevalence of antibiotic resistance within a large microbial collection including 530 clinical strains of S. aureus and 408 strains of S. epidermidis to a panel of 16 different drugs. All strains were isolated from orthopedic infections, either associated or non-associated with implant materials. Interestingly, our data show that the profile of the prevalence of antibiotic resistance within the two species of pathogens is extremely similar for the vast majority of the drugs screened. The only statistically significant variations in prevalence concerned, in order of relevance, the following 5 out of 16 antibiotics: sulfamethoxazole (in combination with trimethoprim), erythromycin, and, to a lesser extent, oxacillin, imipenem, and clindamycin. In the case of Staphylococcus aureus, the isolates associated to implant materials were found more frequently resistant to all 4 aminoglycosides screened as well as to ciprofloxacin.
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Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla , Procedimentos Ortopédicos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacos , Humanos , Infecções Relacionadas à Prótese/microbiologia , Infecção da Ferida Cirúrgica/microbiologiaRESUMO
OBJECTIVE: To provide a review of the current information on the etiology, clinical presentation, management, and outcome of pilomatrixoma of the head and neck in children. DESIGN: Retrospective review. SETTING: A tertiary care pediatric center. PATIENTS: Fifty-one pediatric patients with a diagnosis of pilomatrixoma of the head and neck. INTERVENTION: All patients underwent excision of pilomatrixoma from January 1997 to March 1999. A total of 55 tumors were studied. RESULTS: A preponderance of girls (n = 36; 71%) presented with this condition. The average age at diagnosis was 5.7 years, and the average size of the lesion was 1 cm. The skin of the cheek and the periorbital area were the most commonly involved sites. Only 27 lesions (49%) had a correct preoperative diagnosis. Two (4%) of 55 tumors recurred after complete surgical excision. MAIN OUTCOME MEASURES: The age and sex of the patient, preoperative diagnosis, time elapsed before diagnosis, site and size of the tumor, length of follow-up, presence of multiple or previous pilomatrixomas, and recurrence. CONCLUSIONS: Preoperative diagnosis may be improved with increased awareness of pilomatrixoma, a common, benign skin tumor in children. Clinical findings will aid in an accurate diagnosis. Recurrence after complete local excision is rare.
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Doenças do Cabelo , Pilomatrixoma , Dermatopatias , Adolescente , Criança , Pré-Escolar , Feminino , Doenças do Cabelo/diagnóstico , Doenças do Cabelo/patologia , Doenças do Cabelo/cirurgia , Neoplasias de Cabeça e Pescoço/diagnóstico , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Lactente , Masculino , Pilomatrixoma/diagnóstico , Pilomatrixoma/patologia , Pilomatrixoma/cirurgia , Estudos Retrospectivos , Dermatopatias/diagnóstico , Dermatopatias/patologia , Dermatopatias/cirurgiaRESUMO
Chondrocyte tissue engineering continues to be a challenging problem. When chondrocytes are duplicated in vitro, it is imperative to obtain an adequate number of cells of optimal phenotype. A temperature-sensitive polymer gel, a copolymer of poly(N-isopropylacrylamide) and acrylic acid (PNiPAAm-co-Aac), has the ability of gelling at 37 degrees C (the lower critical solution temperature, LCST) or above and liquefying below that temperature (Vernon and Gutowska, Macromol. Symp. 1996;109:155-167). The hypothesis of this study was that chondrocytes could (1) duplicate in the copolymer gel; (2) regain their chondrocyte phenotype; and (3) be easily recovered from the gel by simply lowering the temperature below 37 degrees C. Chondrocytes from adult rabbit scapular cartilage were harvested and cultured in a monolayer culture until confluency (approximately 2 weeks). Next, the cells were harvested and seeded into the copolymer gel and cultured for 2-4 weeks. The phenotype of the cultured cells was then characterized. Two groups of control cultures, monolayer and agarose gel, were used to compare their ability to maintain chondrocyte phenotype. The results showed that chondrocytes isolated from rabbit scapula can re-express chondrocyte phenotype in agarose culture and polymer gel culture but not in monolayer culture. Also, cultured chondrocytes can be easily recovered from polymer gel culture by simply lowering the temperature. This new in vitro method of chondrocyte culture is recommended for chondrocyte propagation and regaining chondrocyte phenotype before cell seeding or transplantation.