RESUMO
The effect of race on breast cancer outcome is confounded by tumor and treatment heterogeneity. We examined a cohort of women with stage II-III breast cancer treated uniformly with neoadjuvant chemotherapy to identify factors associated with racial differences in chemotherapeutic response and long-term survival. Using a prospective database, we identified women with stage II-III breast cancer treated with neoadjuvant chemotherapy from 1998 to 2011. Race was categorized as African-American (AA) or non-AA. Preplanned subtype analyses were stratified by hormone receptor (HR) and HER2. Pathologic response to chemotherapy (pCR), time to recurrence (TTR), and overall survival (OS) were assessed using logistic regression, Kaplan-Meier method, and Cox proportional hazards regression analyses. Of 349 women identified, 102 (29 %) were AA, who were younger (p = 0.03), more obese (p < 0.001), and less likely to have HR+/HER2- tumors (p = 0.01). No significant differences in pCR rate by race were found. At median follow-up of 6.5 years, AA had worse TTR (hazard ratio 1.51, 95 % CI 1.02-2.24), which was attenuated in multivariable modeling, and there was no significant difference in OS. When stratified by HR, worse outcomes were limited to HR+AA (TTR hazard ratio 1.85, 95 % CI 1.09-3.14; OS hazard ratio 2.42 95 % CI 1.37-4.28), which remained significant in multivariable analysis including pCR rate and BMI. With long-term follow-up, racial disparity in outcome was limited to HR+ breast cancer, with no apparent contribution of chemotherapy sensitivity. This suggests that disparity root causes may be driven by HR+ factors such as unmeasured molecular differences, endocrine therapy sensitivity, or adherence.
Assuntos
Antineoplásicos/uso terapêutico , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/etnologia , Terapia Neoadjuvante/métodos , Adulto , Negro ou Afro-Americano/estatística & dados numéricos , Idoso , Neoplasias da Mama/mortalidade , Neoplasias da Mama/patologia , Feminino , Humanos , Pessoa de Meia-Idade , Estudos Prospectivos , Receptor ErbB-2/análise , Receptores de Estrogênio/análise , Receptores de Progesterona/análise , Análise de Sobrevida , Resultado do TratamentoRESUMO
BACKGROUND: The impact of different approaches to fluid management during intraoperative volume resuscitation in patients undergoing major elective surgery is poorly defined. We compared volume effectiveness of crystalloid and colloid substitution aimed to maintain the cardiac index (CI) between 2.6 and 3.8 l/min/m(2) as measured by transesophageal Doppler (TED). METHODS: A total of 115 urological patients were enrolled in the prospective randomized trial and then randomized into 2 groups, one with volume therapy based on crystalloids (n = 57) and the other with colloids (n = 58). A TED probe was inserted and then hemodynamic optimization (therapy with Ringer's solution or hydroxyethyl starch 6 % 130/0.4 and administration of vasoactive drugs) was started according to TED variables to maintain the CI between 2.6 and 3.8 l/min/m(2). RESULTS: We observed high incidence of CI < 2.6 l/min/m(2) after induction of anesthesia (75 %) in both groups. There were no significant differences in demographic characteristics, ASA classification, length of surgery, estimated blood loss and the CI during surgery. To maintain the CI within the requested interval, significantly different amounts of crystalloids were needed as compared to colloid (median: 5000 ml vs 1500 ml). In the CRY group, more patients were treated by vasodilatators (40.4 vs 20.7 %). CONCLUSIONS: The study confirmed that crystalloids and colloids are effective in correcting flow-related perfusion abnormalities. The significant difference between volumes of crystalloids and colloids proved their different characteristics such as unequal distribution between compartments. The expansion of therapeutic algorithm by using vasoactive drugs allows us to avoid adverse events resulting from fluid overload (Tab. 1, Fig. 5, Ref. 35).
Assuntos
Hidratação/métodos , Hipovolemia/complicações , Hipovolemia/terapia , Cuidados Intraoperatórios/métodos , Doenças Urológicas/cirurgia , Procedimentos Cirúrgicos Urológicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Coloides/uso terapêutico , Soluções Cristaloides , Procedimentos Cirúrgicos Eletivos , Feminino , Hemodinâmica , Humanos , Soluções Isotônicas/uso terapêutico , Masculino , Pessoa de Meia-Idade , Assistência Centrada no Paciente/métodos , Estudos Prospectivos , Doenças Urológicas/complicações , Vasodilatadores/uso terapêuticoRESUMO
INTRODUCTION: Severe sepsis is still associated with significant morbidity and mortality, which is however different, as well as its management, depending on the region. What is the situation in the Czech Republic and what is the character of patients with severe sepsis is currently not known. The aim of the project is to describe the processes of care, outcome and characteristics of patients with severe sepsis admitted to the intensive care department of the Czech Republic. METHODS: This is a multicentre and observational project with retrospective enrollment of patients who meet the criteria for severe sepsis before or within 24 hours after admission to selected intensive care units (ICUâEPOSS). RESULTS: 394 patients were analyzed. Median age at admission was 66 (56-â76) years, males predominated (58.9%) and the median APACHE II score on admission was 25 (19-â32). Patients were predominantly medical (56.9%) and most were secondary admitted from other ICU (53.6%). Meeting the criteria of severe sepsis was most frequently within the period (± 4 hours) of admission the EPOSSâICU (77.6%). Median total fluid intake during the first 24 hours was 6,680 (4,840-â9,450) ml. Most patients required mechanical ventilation (58.4%). Compliance with the resuscitation bundle of severe sepsis in our group was very good and was associated with lower mortality of patients. Most frequently, the EPOSSâICU length of stay (LOS) was 7 (3-â15) days and median hospital LOS was 13 (8-â28) days. Hospital mortality in our cohort was 35.8%. CONCLUSION: Introducing the project, which in its first stage obtained valuable and internationally comparable data about patients with severe sepsis admitted to the involved ICU in the Czech Republic.
Assuntos
Infecção Hospitalar/terapia , Unidades de Terapia Intensiva , Sepse/terapia , Adulto , Idoso , Infecção Hospitalar/diagnóstico , Infecção Hospitalar/mortalidade , República Tcheca , Feminino , Fidelidade a Diretrizes , Mortalidade Hospitalar , Humanos , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Projetos Piloto , Respiração Artificial , Ressuscitação , Estudos Retrospectivos , Sepse/diagnóstico , Sepse/mortalidadeRESUMO
After failure of temozolomide, there is no established standard salvage chemotherapy for patients with recurrent glioblastoma (GBM). Two phase II trials combining ifosfamide, carboplatin and etoposide chemotherapy (ICE) showed favorable results. We therefore applied the ICE protocol to 13 patients (10 GBM, 3 anaplastic astrocytomas). Partial or complete remissions were not observed. None of the 13 patients survived progression-free for 6 months. Our retrospective analysis suggests that the ICE regimen is not effective in patients with recurrent high-grade glioma if applied at second or third relapse.
Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Astrocitoma/tratamento farmacológico , Neoplasias Encefálicas/tratamento farmacológico , Glioma/tratamento farmacológico , Adulto , Idoso , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Astrocitoma/secundário , Neoplasias Encefálicas/patologia , Carboplatina/administração & dosagem , Dacarbazina/análogos & derivados , Dacarbazina/uso terapêutico , Esquema de Medicação , Etoposídeo/administração & dosagem , Feminino , Glioma/secundário , Humanos , Ifosfamida/administração & dosagem , Masculino , Pessoa de Meia-Idade , Recidiva , Estudos Retrospectivos , Temozolomida , Falha de TratamentoRESUMO
During the pandemy caused by novel influenza A virus (subgroup H1N1), a significant number of patients became critically ill from respiratory failure. In the most severe cases of primary pneumonia, patients develop refractory hypoxemic acute respiratory distress syndrome (ARDS) with typical computed tomographic findings of multi-lobar alveolar opacities and extremely reduced pulmonary airspace. To reduce the risk of injurious ventilation and promote survival, some authors recommend the use of extracorporeal membrane oxygenation (ECMO). Unfortunately, ECMO is expensive, associated with serious complications, and available at very few centers. Other therapeutic options are clearly needed. Here we report three patients with severe influenza pneumonia who recovered following treatment with porcine surfactant (Tab. 1, Fig. 3, Ref. 6). Full Text in free PDF www.bmj.sk.
Assuntos
Vírus da Influenza A Subtipo H1N1 , Influenza Humana/complicações , Surfactantes Pulmonares/uso terapêutico , Síndrome do Desconforto Respiratório/tratamento farmacológico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Radiografia , Síndrome do Desconforto Respiratório/diagnóstico por imagem , Síndrome do Desconforto Respiratório/fisiopatologia , Síndrome do Desconforto Respiratório/virologiaRESUMO
Ventilator-associated pneumonia (VAP) is defined as pneumonia occurring in a patient after intubation with an endotracheal tube or tracheostomy tube lasting for 48 hours or more. It is also one of the most common and fatal infections of patients in ICUs. The diagnostic process in VAP is still underestimated and precise criteria for diagnosis are inconsistent. Delayed diagnosis and subsequent delay in starting appropriate therapy are associated with worse outcomes in patients with VAP. Appropriate dose, adequate route of administration and reasonable length of antibiotic therapy together with de-escalation are the fundamental principles of therapy. Supportive care is also an integral part of the treatment. Implementing preventive procedures according to the local ICU standards is needed for reducing the incidence of VAP effectively.
Assuntos
Pneumonia Associada à Ventilação Mecânica , Humanos , Pneumonia Associada à Ventilação Mecânica/diagnóstico , Pneumonia Associada à Ventilação Mecânica/tratamento farmacológico , Pneumonia Associada à Ventilação Mecânica/prevenção & controleRESUMO
Pulse dye densitometry (PDD) enables the evaluation of hemodynamic state as well as liver function. A repeated examination, even after a short pause (or under stress condition), enables to follow safely the dynamics of liver pathology. From presented parameters we have evaluated as reliable the C5-clearance, an expression of equilibrium state in the two compartment liver system. Furthermore, T-index expresses ratio of C5 value to cardiac output, it is a sensitive indicator of the blood pole, i.e. sinusoidal uptake, which is in very good correlation with staging of hepatopathies. The isolated h constant in correlation to T-index is valuable For functional grading. The Japanese automatic analyzer of indocyanine green (ICG) dilution and elimination curves, after incorporation of a two compartment mathematical model, becomes more useful for complex hepatological diagnostics. Non-invasive PDD is becoming of uppermost importance to clinical interest, yielding comparable results as other complicated and invasive examinations and may be, therefore, repeated in short time intervals for different indications with minimal stress of examined patient.
Assuntos
Densitometria/métodos , Fígado Gorduroso/diagnóstico , Fígado Gorduroso/metabolismo , Testes de Função Hepática/métodos , Modelos Biológicos , Adulto , Idoso , Compartimentos de Líquidos Corporais , Débito Cardíaco , Corantes/farmacocinética , Densitometria/normas , Feminino , Humanos , Verde de Indocianina/farmacocinética , Testes de Função Hepática/normas , Masculino , Pessoa de Meia-Idade , Dinâmica não Linear , Análise de Regressão , Reprodutibilidade dos Testes , Adulto JovemRESUMO
Excessive forms of the response of organism to infection play an important role in the pathogenesis of severe sepsis. They may consist of either local pro-inflammatory response with a massive release of cytokines into the systemic circulation, or may be presented as an excessive systemic anti-inflammatory response. In the first case, the result is a systemic pro-inflammatory state, characterised by natural stages of the inflammatory response, in which dysfunction of macrocirculation is followed by microcirculation derangement and mitochondrial alteration at the end. These mechanisms are responsible for the development of remote organs failure. The result in the second case is a deactivation of local immunocompetent cells, which results in the risk of uncontrollable growth of microorganisms, especially in organs with an impaired antimicrobial barrier. This may explain the clinically observed recurrence of septic episodes, when a resolution of infection at one site is later replaced with an outbreak of sepsis from another site. A number of therapeutic interventions aimed on the management of causes and consequences of systemic pro-inflammatory state was clinically tested (e.g. antibiotics, goal directed hemodynamic support and inhibitors of coagulation) with surprisingly different effectiveness. The cause of this difference may lie, apart from the frequently discussed inhomogeneity of the studied patient population, also in an incorrect timing of the therapeutic interventions, which does not respect natural stages of the inflammatory response (Fig. 1, Ref. 40).
Assuntos
Sepse/fisiopatologia , Humanos , Sepse/terapia , Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Síndrome de Resposta Inflamatória Sistêmica/terapiaRESUMO
Despite multidisciplinary local and systemic therapeutic approaches, the prognosis for most patients with brain metastases is still dismal. The role of adaptive and innate anti-tumor response including the Human Leukocyte Antigen (HLA) machinery of antigen presentation is still unclear. We present data on the HLA class II-chaperone molecule CD74 in brain metastases and its impact on the HLA peptidome complexity.We analyzed CD74 and HLA class II expression on tumor cells in a subset of 236 human brain metastases, primary tumors and peripheral metastases of different entities in association with clinical data including overall survival. Additionally, we assessed whole DNA methylome profiles including CD74 promoter methylation and differential methylation in 21 brain metastases. We analyzed the effects of a siRNA mediated CD74 knockdown on HLA-expression and HLA peptidome composition in a brain metastatic melanoma cell line.We observed that CD74 expression on tumor cells is a strong positive prognostic marker in brain metastasis patients and positively associated with tumor-infiltrating T-lymphocytes (TILs). Whole DNA methylome analysis suggested that CD74 tumor cell expression might be regulated epigenetically via CD74 promoter methylation. CD74high and TILhigh tumors displayed a differential DNA methylation pattern with highest enrichment scores for antigen processing and presentation. Furthermore, CD74 knockdown in vitro lead to a reduction of HLA class II peptidome complexity, while HLA class I peptidome remained unaffected.In summary, our results demonstrate that a functional HLA class II processing machinery in brain metastatic tumor cells, reflected by a high expression of CD74 and a complex tumor cell HLA peptidome, seems to be crucial for better patient prognosis.
Assuntos
Antígenos CD/metabolismo , Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/secundário , Genes MHC da Classe II , Sialiltransferases/metabolismo , Antígenos CD/genética , Biomarcadores Tumorais/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Neoplasias Encefálicas/mortalidade , Linhagem Celular Tumoral , Estudos de Coortes , Metilação de DNA , Técnicas de Silenciamento de Genes , Humanos , Estimativa de Kaplan-Meier , Melanoma/metabolismo , Melanoma/patologia , Prognóstico , Regiões Promotoras Genéticas , Sialiltransferases/genética , Linfócitos T/metabolismo , Linfócitos T/patologiaRESUMO
AIM: Overview of recent knowledge about risks and benefits of blood transfusion. TYPE OF STUDY: Review article. SETTING: Department of Anaesthesiology and Intensive Care, University Hospital, Ostrava. METHODS: Summary of previously published data. CONCLUSION: Transfusion of blood and blood products remains controversial in clinical practice. Neither indication and timing nor benefit of this procedure is clearly determined. Previously often reported complications as blood-group incompatibility and infection are less frequent now, and new transfusion's side effects as TRIM (transfusion-related immunomodulation) and TRALI (transfusion-related lung injury) are reported with growing evidence. This risk (often underestimated in the past) is discussed in the article, and compared with blood transfusion benefits. Either restrictive or more open approach to blood transfusion are supported as well as criticised by different groups of clinicians and "good clinical practice" definition remains open for the future.
Assuntos
Transfusão de Sangue , Tolerância Imunológica , Pneumopatias/etiologia , Humanos , Reação TransfusionalRESUMO
BACKGROUND: The importance of normal development of hemispheric dominance and its significance for the development of an individual is sufficiently known. The internationally not well known procedure according to Zlab (1) represents one of the most suitable examinations for right-handedness and laterality testing. METHODS AND RESULTS: In our study we used one of the most popular questionnaires for phenotype testing of handedness- Edinburgh's Inventory (2). According to this questionnaire we have examined 65 children 10 years of age (+/- one year), and classified them into 3 groups: a) pure right-handed (n = 51), b) pure left-handed (n = 5) (all have fulfilled +90-100% resp. -90-100% of answers on corresponding ten questions) and c) a group of mixed laterality--ambidextrous (n = 9). The questionnaire we have accomplished by means of objective testing of hair whorl direction presupposed clockwise in right-handed and counter clockwise in lefthanded. Some of other tests we used turn to be more reliable than lid opening and using a broom (upper hand) by "dominant" hand used in Edinburg's Handedness Inventory. We have examined also hand, elbow, knee and leg joints excursibiliy (enlarged passivity and/or diminished muscle tonus) to define cerebellar dominance: right cerebellar hemisphere in right-handed and left cerebellar hemisphere in left-handed. In the group of pure right-handers we found clockwise hair whorl in 23 of 25 boys. In girls (probably due tu various hair combing) we found clockwise hair whorl only in 12 of 26 children. CONCLUSIONS: Examination of the hair whorl direction seems to be enrichment for a quick clinical phenotype and genotype laterality testing.
Assuntos
Dominância Cerebral/genética , Lateralidade Funcional/genética , Cabelo/crescimento & desenvolvimento , Criança , Feminino , Humanos , MasculinoRESUMO
Severe sepsis is at present serious medical and social problem. In contrast to many other diseases its incidence shows an upward tendency and so does mortality due to sepsis. From the point of view of pathogenesis the cause of this complaint is a disturbed response to infection. The basis of this disruption is either a huge local inflammation that goes hand in hand with the penetration of proinflammatory cytokines into systemic circulation or an excessive proinflammatory systemic response. In the first instance the consequence is a systemic proinflammatory response accompanied by a disruption of macrocirculation, later also of microcirculation and finally mitochondrial failure. These mechanisms are responsible for the gradual failure of distant organs. In the second instance the consequence is a deactivation of systemic and local immunocompetent cells accompanied by the risk of uncontrolled proliferation of microorganisms. Affected are organs with a disturbed antimicrobial barrier, especially the lungs du ring mechanical ventilation, the bloodstream or the urinary system during catheterization. A large group of selectively acting preparations has been clinically tested in the management of this disorder, but only very few of these preparations were efficacious. We may postulate that the great diversity of the investigated population of patients was responsible for this lack of success.
Assuntos
Síndrome de Resposta Inflamatória Sistêmica/fisiopatologia , Trato Gastrointestinal/fisiopatologia , Humanos , Inflamação , Mediadores da Inflamação/metabolismo , Síndrome de Resposta Inflamatória Sistêmica/imunologia , Sistema Vasomotor/fisiopatologiaRESUMO
New multiparametric analysis and method of their evaluation were derived. The bolus dye injection is used for evaluation of ICG (indicyaningreen) and BSP (bromsulphophtalein) kinetics. This arrangement is a form of spectrophotometric measurement of BSP in plasma and/or pulse dye densitometry of ICG. Clearance values enable to differentiate liver diseases and to add their clinical staging. Pathophysiology of dye kinetics is discussed from two points of view i.e. sinusoidal and canalicular membrane transfer.
Assuntos
Hepatopatias/diagnóstico , Testes de Função Hepática/métodos , Corantes , Humanos , Indicadores e Reagentes , Verde de Indocianina , SulfobromoftaleínaRESUMO
Review article deals with traffic accidents in our country and the problems of their causes. In comparison with economically developed countries traffic accidents prevalence raised since 1990 till 1995 and with small decline in 2004 it remains on a high level of 140 deaths in traffic accidents for I million of inhabitants, which makes the Czech Republic one of the worst among the compared countries. In agreement with present views, the main course of accidents is the human error. Attention is given to traffic accidents prevalence of young men versus young women, and to the evaluation of psycho-physiologic functions in elderly drivers. Personal qualities are among the most important in the neglecting of traffic rules, in the aggressivity, non-tolerance and disrespect to the freedom of others. Besides the building of the more perfect infrastructure, it is necessary to improve the register of accident recidivist drivers and for accidents and repeated accidents to promote compulsory psycho-neurological examination. Similarly to preventive check outs for alcohol, it s necessary to introduce similar measures to cope with growing effects of drugs.
Assuntos
Acidentes de Trânsito/psicologia , Acidentes de Trânsito/estatística & dados numéricos , República Tcheca/epidemiologia , Feminino , Humanos , Masculino , Doenças do Sistema Nervoso , Personalidade , Transtornos Relacionados ao Uso de SubstânciasRESUMO
The efficacy of intravenous infusion of dextran 70 or subcutaneous administration of low-dose heparin in preventing postoperative thromboembolic complications has been investigated in a prospective randomized trial. During part 1 of the study, 232 patients over the age of 40 years who were undergoing major gynecologic surgery underwent a complete test protocol. The 125I fibrinogen uptake test (FUT) was used for the diagnosis of deep vein thrombosis (DVT) in 117 patients in the dextran and 115 patients in the heparin group. Heparin was significantly more effective than dextran for reducing DVT (P less than .001). During part 2 of the study no FUT was done but the incidence of clinical and fatal pulmonary embolism (PE) and the number of complications were studied. Of 444 patients (parts 1 and 2) 1 fatal and 2 nonfatal pulmonary emboli were diagnosed. All the emboli occurred in the dextran group. The benefit: hazard ratio appeared to favor heparin for the prophylaxis of DVT.
Assuntos
Dextranos/administração & dosagem , Heparina/administração & dosagem , Complicações Pós-Operatórias/prevenção & controle , Tromboembolia/prevenção & controle , Adulto , Ensaios Clínicos como Assunto , Dextranos/efeitos adversos , Dextranos/uso terapêutico , Feminino , Heparina/efeitos adversos , Heparina/uso terapêutico , Humanos , Infusões Parenterais , Injeções Subcutâneas , Pessoa de Meia-Idade , Complicações Pós-Operatórias/epidemiologia , Embolia Pulmonar/epidemiologia , Embolia Pulmonar/prevenção & controle , Risco , Tromboflebite/epidemiologia , Tromboflebite/prevenção & controleRESUMO
Six Norway spruce stands (Picea abies L.) in southern Sweden and six in the northeastern Czech Republic, 12 stands in total, were selected for short-term investigations during the summer and autumn of 1991. In each of the plots, an assessment of foliar damage and dendrometric measurement of the trees was made. Soil and leaf samples were collected and analyzed for their chemical composition. After statistical evaluation of the most important correlations, it was concluded that the main cause of tree damage in both countries was through the acidification of the soils. In both countries, but especially in the Czech Republic, heavy metal accumulation in the humus layer was observed. The main results of the study were the discovery of the similarity of damage processes in the two countries, despite the differences in their geographic location and ambient air pollution levels
RESUMO
OBJECTIVES: Bee products have been studied extensively for their healing properties and have become part of cosmetic preparations and folk medicine. The major objective of this study was to examine the presence of antimicrobials in various bee products. DESIGN: Propolis, honeycomb lids, pollen, honeycombs, and honey were screened for antimicrobial compounds. Viridans streptococci were used as indicator strains. Ethanol extracts were applied onto paper disks, dried, and put on the surface of nutrient agar plates with the overlay containing viridans streptococci. The plates were then incubated and evaluated the next day for the presence of inhibition zones. The size of the inhibition zone represented a quantitative measure of antimicrobial activity in a sample. Thin-layer chromatography was used for separation of compounds in the samples and biodetection-an overlay with indicator strain-identified the antimicrobial compounds by formation of inhibition zones. RESULTS: Ethanol extracts of propolis and honeycomb lids, as well as honey containing honeycomb lids contained a mixture of antimicrobial compounds in various amounts. Thin-layer chromatography experiments with two different solvent systems differing in polarity suggested that major antimicrobials present in the samples prepared from honeycomb lids, honeycombs, pollen, and propolis have similar properties. These active compounds were not extremely hydrophobic. CONCLUSIONS: Extracts from the tested samples of bee products exhibited antimicrobial properties at various levels depending on the sample and bacterial species used for testing. Using chromatographic techniques, we demonstrated similar properties of the active compounds in various active samples. In conclusion, our results suggest that honey containing honeycomb lids may be a beneficial food supplement because of the presence of antibacterial compounds.
Assuntos
Antibacterianos/farmacologia , Mel , Própole/farmacologia , Streptococcus/efeitos dos fármacos , Animais , Cromatografia em Camada Fina , Testes de Sensibilidade MicrobianaRESUMO
Many dental and periodontal diseases are largely a question of bacterial etiology. Dental caries develop due to an increase of strongly acidogenic and aciduric gram-positive bacteria while common forms of periodontal disease are linked to anaerobic gram-negative bacteria in subgingival plaque. Many plants and plant-derived antimicrobial components are used in folklore therapeutics for the treatment of periodontal disorders and for the purposes of oral hygiene. Some have been evaluated for possible use in modern medicine, while thousands of other potentially useful/plants have not been tested. In this study, we evaluated the feasibility of screening for antibacterials isolated from plants with activity against three representatives of oral streptococci. We developed and tested the following methodologies: (1) Extraction of antibacterial components from plants; (2) Assays for antibacterial activity; (3) Chromatographic methods for initial analysis of compounds of interest. The screening process for plant antimicrobials consisted of extraction of plant material and assay of antibacterial activity using a spotting test with the selected oral streptococci as indicator strains. In addition, we developed chromatographic procedures that allow characterization and optimization of initial isolation steps. Depending on the indicator microorganisms used, the screening assay can target additional pathogens including other streptococci (group A and B, and pneumococci) and periodontal pathogens such as Porphyromonas. Also, we noted that the activity of some extracts varied against different oral bacteria. Our conclusion, supported by extensive data, was that the screening for antimicrobials from plants is a feasible approach to the identification of natural compounds with antimicrobial properties against dental pathogens.
Assuntos
Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Streptococcus mutans/efeitos dos fármacos , Streptococcus sanguis/efeitos dos fármacos , Streptococcus sobrinus/efeitos dos fármacos , Cromatografia em Camada Fina , Estudos de Viabilidade , Humanos , Testes de Sensibilidade MicrobianaRESUMO
An active control system based on the acoustic energy density is investigated. The system is targeted for use in three-dimensional enclosures, such as aircraft cabins and rooms. The acoustic energy density control method senses both the potential and kinetic energy densities, while the most popular control systems of the past have relied on the potential energy density alone. Energy density fields are more uniform than squared pressure fields, and therefore, energy density measurements are less sensitive to sensor location. Experimental results are compared to computer-generated results for control systems based on energy density and squared pressure for a rectangular enclosure measuring 1.5 x 2.4 x 1.9 m. Broadband and narrowband frequency pressure fields in the room are controlled experimentally. Pressure-field and mode-amplitude data are presented for the narrowband experiments, while spectra and pressure-field data are presented for the broadband experiment. It is found that the energy density control system has superior performance to the squared pressure control system since the energy density measurement is more capable of observing the modes of a pressure field. Up to 14.4 and 3.8 dB of cancellation are achieved for the energy density control method for the narrowband and broadband experiments presented, respectively.
RESUMO
The investigation of an active control system based on acoustic energy density has led to the analysis and development of an inexpensive three-axes energy density sensor. The energy density sensor comprises six electret microphones mounted on the surface of a 0.025-m (1 in.) radius sphere. The bias errors for the potential, kinetic, and total energy density as well as the magnitude of intensity of a spherical sensor are compared to a sensor comprising six microphones suspended in space. Analytical, computer-modeled, and experimental data are presented for both sensor configurations in the case of traveling and standing wave fields, for an arbitrary incidence angle. It is shown that the energy density measurement is the most nearly accurate measurement of the four for the conditions presented. Experimentally, it is found that the spherical energy density sensor is within +/- 1.75 dB compared to reference measurements in the 110-400 Hz frequency range in a reverberant enclosure. The diffraction effects from the hard sphere enable the sensor to be made more compact by a factor of 3 compared to the sensor with suspended microphones.