Comparative assessment of seller’s staining test (SST) and direct fluorescent antibody test for rapid and accurate laboratory diagnosis of rabies.

Background: Rabies causes 55, 000 annual human deaths globally and about 10,000 people are exposed annually in Nigeria. Diagnosis of animal rabies in most African countries has been by direct microscopic examination. In Nigeria, the Seller’s stain test (SST) was employed until 2009. Before then, both SST and dFAT were used concurrently until the dFAT became the only standard method. Objective: This study was designed to assess the sensitivity and specificity of the SST in relation to the ‘gold standard’ dFAT in diagnosis of rabies in Nigeria. Methods: A total of 88 animal specimens submitted to the Rabies National Reference Laboratory, Nigeria were routinely tested for rabies by SST and dFAT. Results: Overall, 65.9% of the specimens were positive for rabies by SST, while 81.8% were positive by dFAT. The sensitivity of SST in relation to the gold standard dFAT was 81.0% (95% CIs; 69.7% - 88.6%), while the specificity was 100% (95% CIs; 76% - 100%). Conclusion: The relatively low sensitivity of the SST observed in this study calls for its replacement with the dFAT for accurate diagnosis of rabies and timely decisions on administration of PEP to prevent untimely deaths of exposed humans.

Comparison of two laboratory-developed PCR methods for the diagnosis of Pulmonary Tuberculosis in Brazilian patients with and without HIV infection

Abstract Background Direct smear examination with Ziehl-Neelsen (ZN) staining for the diagnosis of pulmonary tuberculosis (PTB) is cheap and easy to use, but its low sensitivity is a major drawback, particularly in HIV seropositive patients. As such, new tools for laboratory diagnosis are urgently needed to improve the case detection rate, especially in regions with a high prevalence of TB and HIV. Objective To evaluate the performance of two in house PCR (Polymerase Chain Reaction): PCR dot-blot methodology (PCR dot-blot) and PCR agarose gel electrophoresis (PCR-AG) for the diagnosis of Pulmonary Tuberculosis (PTB) in HIV seropositive and HIV seronegative patients. Methods A prospective study was conducted (from May 2003 to May 2004) in a TB/HIV reference hospital. Sputum specimens from 277 PTB suspects were tested by Acid Fast Bacilli (AFB) smear, Culture and in house PCR assays (PCR dot-blot and PCR-AG) and their performances evaluated. Positive cultures combined with the definition of clinical pulmonary TB were employed as the gold standard. Results The overall prevalence of PTB was 46% (128/277); in HIV+, prevalence was 54.0% (40/74). The sensitivity and specificity of PCR dot-blot were 74% (CI 95%; 66.1%-81.2%) and 85% (CI 95%; 78.8%-90.3%); and of PCR-AG were 43% (CI 95%; 34.5%-51.6%) and 76% (CI 95%; 69.2%-82.8%), respectively. For HIV seropositive and HIV seronegative samples, sensitivities of PCR dot-blot (72% vs 75%; p = 0.46) and PCR-AG (42% vs 43%; p = 0.54) were similar. Among HIV seronegative patients and PTB suspects, ROC analysis presented the following values for the AFB smear (0.837), Culture (0.926), PCR dot-blot (0.801) and PCR-AG (0.599). In HIV seropositive patients, these area values were (0.713), (0.900), (0.789) and (0.595), respectively. Conclusion Results of this study demonstrate that the in house PCR dot blot may be an improvement for ruling out PTB diagnosis in PTB suspects assisted at hospitals with a high prevalence of TB/HIV.

A boarding school outbreak of pertussis in adolescents : value of laboratory diagnostic methods

Culture for Bordetella pertussis (B. pertussis) is the traditional gold standard for laboratory diagnosis of pertussis but is insensitive, especially later in the course of illness and in vaccinated persons. Interpretation of serology is limited by the lack of an appropriate reference standard. An outbreak of pertussis in a crowded boarding-school dormitory allowed evaluation of laboratory correlates of infection. Questionnaires, serum samples and throat swabs were collected from members of the exposed group. Serum samples from unexposed controls of a similar age group were used for comparison. B. pertussis PCR was performed on throat swabs, and sera were tested for IgA antibodies against whole-cell (WC) B. pertussis antigen and IgG antibodies to pertussis toxin (PT). The Centers for Disease Control and Prevention definition for pertussis was used to define clinical cases. We evaluated the use of a previously published cut-off for PT IgG of 125 EIA units (EU)/ml. Completed questionnaires were obtained from 115 students, of whom 85 (74%) reported coughing symptoms, including 32 (28%) who met the clinical case definition for pertussis. B. pertussis was detected by PCR in 17 (15%) and WC IgA in 22 (19%) students; neither correlated with symptoms, but dormitory of residence strongly predicted PCR status. The mean PT IgG geometric mean concentration, in this situation of high pertussis exposure, correlated with severity of symptoms and was significantly higher in both symptomatic and asymptomatic children exposed during the outbreak (P<0·001) than in control children. A cut-off for PT IgG of 125 EU/ml was too high in an outbreak situation to be sensitive enough to identify pertussis cases. A case of pertussis in a crowded boarding-school dormitory resulted rapidly in an outbreak. Serology and PCR were useful in identifying the outbreak and commencing disease control measures. The use of serology has mostly been evaluated in community serosurveys, where it is not possible to determine if immunity reflects vaccination, asymptomatic disease or symptomatic disease. This outbreak gave us the opportunity to evaluate the value of serology and PCR in the presence of confirmed exposure to pertussis.

PP65 antigenemia in the diagnosis of cytomegalovirus infection in AIDS patients

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Assessment of clinical scoring systems for the diagnosis of Williams-Beuren syndrome

Williams-Beuren syndrome (WBS) is a genetic disorder characterized by physical and intellectual developmental delay, associated with congenital heart disease and facial dysmorphism. WBS is caused by a microdeletion on chromosome 7 (7q11.23), which encompasses the elastin (ELN) gene and about 27 other genes. The gold standard for WBS laboratory diagnosis is FISH (fluorescence in situ hybridization), which is very costly. As a possible alternative, we investigated the accuracy of three clinical diagnostic scoring systems in 250 patients with WBS diagnosed by FISH. We concluded that all three systems could be used for the clinical diagnosis of WBS, but they all gave a low percentage of false-positive (6.0-9.2%) and false-negative (0.8-4.0%) results. Therefore, their use should be associated with FISH testing. © FUNPEC-RP.

Human toxocariasis: diagnosis, worldwide seroprevalences and clinical expression of the systemic and ocular forms.

Although human toxocariasis ranks among the most common zoonotic infections worldwide, it remains relatively unknown to the public. The causal agents are the nematode parasites Toxocara canis and T. cati, whose definitive hosts are dogs and cats, respectively. When embryonated eggs are accidentally ingested by humans, larvae hatch in the small intestine, penetrate the intestinal wall and migrate, via the bloodstream, to the liver, lungs, muscles, eye and central nervous system. Although most human infections are asymptomatic, two well-defined clinical syndromes are classically recognised: visceral larva migrans (a systemic disease caused by larval migration through major organs) and ocular larva migrans (a disease limited to the eyes and optic nerves). Two less-severe syndromes have recently been described, one mainly in children (covert toxocariasis) and the other mainly in adults (common toxocariasis). Here, the current laboratory diagnosis, epidemiology and main clinical features of both the systemic and ocular forms of human toxocariasis are reviewed. New developments in serological diagnosis are described, the available seroprevalence data are analysed, and the results of relevant clinical studies that have been published over the last decade are explored, to provide an updated overview of this neglected but highly prevalent human infection.

Diagnosis of central venous catheter related infection in adult patients

Intravascular catheters are one of the main causes of bacteraemia and septicaemia in hospitalised patients and continue to be associated with a significant morbidity and mortality. Two main types of infections occur, they can be either localised at the catheter insertion site of systemic with a septicaemia. The clinical parameters related to these infections are presented. The laboratory diagnosis of these infections is also extensively reviewed and recommendations are made as to the most appropriate diagnostic method to be used. © 2005 The British Infection Society. Published by Elsevier Ltd. All rights reserved.

Produção de porfirinas por corynebacterium diphtheriae

A produção de porfirinas por Corynebacterium diphtheriae é um objeto de estudo antigo, porém pouco explorado em Química e Ciências Médicas. O presente trabalho teve como objetivos comparar a influência de diferentes meios de cultura na produção de porfirinas por Corynebacterium diphtheriae, determinar a influencia da concentração do ferro na produção de porfirina, comparar quantitativamente a produção de porfirinas por diferentes amostras de bacilo diftérico e caracterizar químicamente os tipos de porfirinas produzidas. As técnicas utilizadas para isso foram a espectroscopia de absorção UV-visível e de fluorescência. O meio de cultura descrito por Mueller (1939), para a produção de toxina, se mostrou mais eficiente que o meio B de king, utilizado no diagnóstico laboratorial da difteria. A concentração de ferro no cultivo de Corynebacterium diphtheriae influencia a produção de porfirina. Altas concentrações de ferro inibem a produção de porfirina. A concentração de ferro onde a produção de porfirinas é máxima é de 0,20g/mL. Dentre as 11 amostras de bacilo diftérico estudadas, a amostra HC03, fermentadora de sacarose e toxinogênica, isolada de um caso de endocardite, foi a maior produtora de porfirina. A amostra ATCC de Corynebacterium ulcerans, não fermentadora de sacarose e toxinogênica, foi a amostra que produziu menos porfirina. Todas as 11 amostras apresentaram o mesmo perfil de espectro de fluorescência, sugerindo que a porfirina produzida seja a mesma nas amostras pesquisadas. As análises feitas para a caracterização do tipo de porfirina produzida levam a crer que esta seja uma coproporfirina. Os espectros de absorção e fluorescência não permitem porém determinar o(s) isômero(s) presente(s).

Estudo das características fenotípicas e genotípicas de amostras de Corynebacterium pseudotuberculosis

Uma vez que C. pseudotuberculosis é o agente etiológico de processos infecciosos em animais caprinos e ovinos e que também pode ser isolado de processos infecciosos em seres humanos as investigações direcionadas para a espécie em questão são necessárias, visto que a escassez de dados epidemiológicos e de conhecimento relativo ao comportamento do microrganismo em hospedeiros animais e humanos em nosso país dificulta o diagnóstico laboratorial da espécie, à semelhança do observado com outra espécie de transmissão zoonótica, o C. ulcerans. Uma preocupação adicional é o fato da espécie em questão também ser capaz de albergar bacteriófagos codificadores da toxina diftérica, representando uma ameaça à circulação dos bacteriófagos. Assim, o presente estudo tem como objetivo geral analisar as características fenotípicas e genotípicas de amostras de C. pseudotuberculosis. Neste sentido, foram propostos os seguintes objetivos: Avaliar as características bioquímicas das amostras através de testes bioquímicos convencionais; avaliar as características bioquímicas das amostras utilizando o sistema semi-automatizado API Coryne; diferenciar amostras de C. pseudotuberculosis de C. ulcerans utilizando a técnica de PCR multiplex; pesquisar a presença de gene tox. Os resultados demonstraram que amostras de C. diphtheriae, C. ulcerans e C. pseudotuberculosis podem ser caracterizadas por métodos bioquímicos convencionais e por taxonomia numérica (API Coryne System). C. ulcerans e C. pseudotuberculosis, com potencial de circulação zoonótica, da mesma forma que C. diphtheriae são capazes de albergar o gene da toxina diftérica. A reação m-PCR foi capaz de discernir as amostras de C. diphtheriae, C. ulcerans e C. pseudotuberculosis e ainda definir o potencial das amostras em produzir a toxina diftérica. Os dados enfatizam a necessidade da técnica multiplex PCR para o diagnostico e para o controle de espécies associadas a quadros de difteria em populações humana.

Rapid detection of porcine circovirus type 2 by loop-mediated isothermal amplification

A method of loop-mediated isothermal amplification (LAMP) was employed to develop a rapid and simple detection system for porcine circovirus type 2 (PCV2). The amplification could be finished in 60 min under isothermal condition at 64 degrees C by employing a set of four primers targeting the cap gene of PCV2. The LAMP assay showed higher sensitivity than the conventional PCR, with a detection limit of five copies per tube of purified PCV2 genomic DNA. No cross-reactivity was observed from the samples of other related viruses including porcine circovirus type 1 (PCV1), porcine parvovirus (PPV), porcine pseudorabies virus (PRV) and porcine reproductive and respiratory syndrome virus (PRRSV). The detection rate of PCV2 LAMP for 86 clinical samples was 96.5% and appeared greater than that of the PCR method. The LAMP assay reported can provide a rapid yet simple test of PCV2 suitable for laboratory diagnosis and pen-side detection due to ease of operation and the requirement of only a regular water bath or heat block for the reaction. (c) 2008 Elsevier B.V. All rights reserved.

Carga viral de seis tipos de Virus del Papiloma Humano de alto riesgo y su asociacion con lesiones cervicales

Introducción: La infección por un tipo de Virus del Papiloma Humano de alto riesgo (VPH-AR), es el factor principal en el desarrollo de Cáncer de Cérvix (CC). La carga viral puede modular esta asociación, por lo que resulta importante su cuantificación y el establecimiento de su relación con lesiones precursoras de CC. Metodología: 60 mujeres con lesiones escamosas intraepiteliales (LEI) y 120 mujeres sin LEI, confirmadas por colposcopia, fueron incluidas en el estudio. Se determinó la carga viral de 6 tipos de VPH-AR, mediante PCR en tiempo real. Se estimaron OR crudos y ajustados para evaluar la asociación entre la carga viral de cada tipo y las lesiones cervicales. Resultados: 93.22% de mujeres con LEI y 91.23% de mujeres negativas, fueron positivas para al menos un tipo de VPH. VPH-18 y VPH-16 fueron los tipos más prevalentes, junto con VPH-31 en mujeres sin LEI. No se encontraron diferencias estadísticamente significativas de las cargas virales entre éstos dos grupos, aunque se observó un mayor carga viral en lesiones para algunos tipos virales. Una mayor frecuencia de lesiones se asoció a infecciones con carga baja de VPH-16 (ORa: 3.53; IC95%: 1.16 – 10.74), en comparación a mujeres con carga alta de VPH-16, (ORa: 2.63; IC95%: 1.09 – 6.36). En infecciones por VPH-31, la presencia de carga viral alta, se asoció con una menor frecuencia de lesiones (ORa: 0.34; IC95%: 0.15 – 0.78). Conclusiones: La prevalencia tipo-específica de VPH se corresponde con las reportadas a nivel mundial. La asociación entre la carga viral del VPH y la frecuencia de LEI es tipo específica y podría depender de la duración de la infección, altas cargas relacionadas con infecciones transitorias, y bajas cargas con persistentes. Este trabajo contribuye al entendimiento del efecto de la carga viral en la historia natural del CC; sin embargo, estudios prospectivos son necesarios para confirmar estos resultados.

Content validity of visual analog scales to assess symptom severity of acute angioedema attacks in adults with hereditary angioedema : an interview study

Background: Hereditary angioedema (HAE) is a rare, debilitating, potentially life-threatening condition characterized by recurrent acute attacks of edema of the skin, face/upper airway, and gastrointestinal and urogenital tracts. During a laryngeal attack, people with HAE may be at risk of suffocation, while other attacks are often associated with intense pain, disfigurement, disability, and/or vomiting. The intensity of some symptoms is known only to the person experiencing them. Thus, interview studies are needed to explore such experience and patient-reported outcome measures (PROMs) are required for systematic assessment of symptoms in the clinical setting and in clinical trials of treatments for acute HAE attacks.

Objective: The aim of this interview study was to assess the content validity and suitability of four visual analog scale (VAS) instruments for use in clinical studies. The VAS instruments were designed to assess symptoms at abdominal, oro-facial-pharyngeal-laryngeal, peripheral, and urogenital attack locations. This is the first known study to report qualitative data about the patient's experience of the rare disorder, HAE.

Methods: Semi-structured exploratory and cognitive debriefing interviews were conducted with 27 adults with a confirmed clinical/laboratory diagnosis of HAE (baseline plasma level of functional plasma protein C1 esterase inhibitor [C1INH] <50% of normal without evidence for acquired angioedema). There were 17 participants from the US and 10 from Italy, with mean age 42.5 (SD 14.5) years, range 18–72 years, mean HAE duration 21.3 (SD 14.1) years, range 1–45 years, 67% female, and 44% VAS-naïve. Experience of acute angioedema attacks was first explored, noting spontaneous mentions by participants of HAE symptomatology. Cognitive debriefing of the VAS instruments was undertaken to assess the suitability, comprehensibility, and relevance of the VAS items. Asymptomatic participants completed the VAS instruments relevant to their angioedema experience, reporting as if they were experiencing an acute angioedema attack at the time. Interviews were conducted in the clinic setting in the US and Italy over an 8-month period.

Results: Participants mentioned spontaneously almost all aspects of acute angioedema attacks covered by the four VAS instruments, thus providing strong support for inclusion of nearly all VAS items, with no important symptoms missing. Predominant symptoms found to be associated with acute angioedema attacks were edema and pain, and there was evidence of varying degrees of disruption to everyday activities supporting the inclusion of an overall severity item reflecting the disabling effects of HAE symptoms. VAS item wording was understood by participants.

Conclusion: This interview study explored and reported the patient experience of HAE attacks. It demonstrated the content validity of the four anatomical location HAE VAS instruments and their suitability for use in clinical trials of recombinant human C1INH (rhC1INH) treatment for ascertaining trial participants' assessments of the severity of acute angioedema symptoms.

Aspectos epidemiológicos da paratuberculose bovina no Rio Grande do Sul

Descrevem-se os achados clínicos e patológicos da paratuberculose em uma criação intensiva de bovinos de leite no municí pio de Capela de Santana, RS. Os sinais clínicos foram observados em oito de um total de 345 bovinos, consistindo em diarréia crônica refratária aos tratamentos, emagrecimento progressivo e queda na produção de leite. As principais lesões macroscópicas, observadas nos oito animais necropsiados, incluíam intestino delgado com acentuado espessamento da parede e superfície mucosa de aspecto reticulado, semelhante às circunvoluções cerebrais, lesão essa perceptível, através da serosa. A luz intestinal estava preenchida com conteúdo fluido e de aspecto leitoso. Os vasos linfáticos do mesentério mostravam-se mais evidentes sendo que alguns tinham aspecto varicoso. Os linfonodos mesentéricos estavam aumentados de volume e, ao corte, fluía grande quantidade de líquido leitoso. Focos de mineralização foram observados na íntima das artérias, nas válvulas cardíacas e na serosa do rúmen. As principais lesões macroscópicas incluíam enterite, linfadenite e linfangite granulomatosa caracterizada por infiltrado inflamatório com macrófagos, células gigantes de Langhans que continham grande quantidade de bacilos álcool-ácido-resistentes. As lesões vasculares consistiam em degeneração e mineralização das túnicas í ntimas e média das artérias de grande calibre associada a proliferação de colágeno. Havia calcificação da serosa do rúmen atrofia hepatocelular difusa e hepatite granulomatosa multifocal. O M. avium subsp. paratuberculosis (Map) foi isolado em amostras de intestino e linfonodos de 8 vacas Holandesas (3,5%) com doença de Johne, dentre 229 amostras cultivadas provenientes de um rebanho leiteiro. Amostras inoculadas em HEYM com micobactina produziram colônias identificadas como Map, segundo as caracterí sticas fenotí picas próprias como: crescimento lento, coloração álcool-ácido-resistente (A.A.R.) e dependência a micobactina. O laboratório de Referência da OIE confirmou a amostra isolada. O M. avium subsp. paratuberculosis (Map) foi isolado em amostras de intestino e linfonodos de 8 vacas Holandesas (3,5%) com doença de Johne, dentre 229 amostras cultivadas provenientes de um rebanho leiteiro Amostras inoculadas em HEYM com micobactina produziram colônias identificadas como Map, segundo as caracterí sticas fenotí picas próprias como: crescimento lento, coloração álcool-ácido-resistente (A.A.R.) e dependência a micobactina. O laboratório de Referência da OIE confirmou a amostra isolada. Não houve isolamento do agente em 221 amostras intestinais quando processadas, após 2 anos de sua colheita. O teste de IDGA aplicado como “screening”, detectou 26 vacas (11,4%) positivas, dentre 228 animais testados e sacrificados em matadouro. O teste de ELISA adsorvido, utilizando o antí geno PPA-3 detectou 125 (39,8%) amostras positivas. O ELISA não adsorvido detectou mais 32 (10,1%) reagentes positivos, dentre os 314 bovinos testados. A prevalência da infecção causada pelo Map em 36 rebanhos leiteiros procedentes de 25 municí pios do Rio Grande do Sul foi estimada em 44,6% das 1316 amostras testadas. A infecção foi identificada em 35 (97,2%) dos 36 rebanhos testados e presentes em todos os municí pios incluí dos. A ocorrência da doença de Johne foi enfatizada, tanto a forma clí nica quanto a infecção subclí nica no Rio Grande do Sul, sugerindo a adoção de medidas de controle sejam aplicadas na proteção dos rebanhos leiteiros nacionais.

Prevalência da infecção por Chlamydia Trachomatis em mulheres atendidas no Programa de rastreamento do câncer de colo do útero

Genital infection with Chlamydia trachomatis is now recognized as one of the most prevalent sexually transmitted infections (STDs). Despite major advances in laboratory diagnosis techniques, primarily the character of asymptomatic chlamydial infection in both men and in women constitutes the basis for the formation of reservoirs that perpetuate transmission and acquisition of this and other STDs. The asymptomatic in women favors the rise of infection to the upper genital tract, causing injuries that can result in infertility. An examination of population screening for early detection and treatment of asymptomatic infections is the key step in combating this major public health problem. The present study aimed to evaluate the prevalence of infection by C. trachomatis in sexually active women attended the screening program for cervical cancer of the uterus in health facilities in municipalities in different regions of the State of Rio Grande do Norte, and identify factors that may contribute to the spread of this pathogen and its relationship with the lesions of the uterine cervix. It is a cross-sectional study aimed at detecting the presence of genital tract infection by C. trachomatis either in isolated form or in association with human papilloma virus (HPV) infection in asymptomatic women. Were included in this study, a total sample of 1,134 women aged 13-76, mean 34.4 years, from March 2008 to September 2012. Specimens containing exfoliated cells of the epithelium of the uterine cervix were analyzed by examining Pap cytology for the detection of possible injuries, and the polymerase chain reaction (PCR) for detection of plasmid DNA from C. trachomatis and HPV. Infection with C. trachomatis was detected with overall prevalence rate of 8.1% in the isolated form and 2.8% in co-infection with HPV. The infection was detected in 7.4% of women with normal cytology 11.5% of those with atypical cells of undetermined significance (ASC-US) and 16.7% of those with low-grade squamous intraepithelial lesion (LSIL). We observed an association between C. trachomatis and incidence of low-grade squamous intraepithelial lesion (LSIL). The genital tract infection by C. trachomatis alone was associated with education level, ethnicity and parity, revealing that women with higher education, those of non-white ethnicity and those who had three or more pregnancies were more likely to acquire infection. Levels very close to statistical significance were observed for chronological age, age at first sexual intercourse and first pregnancy. There was no association with marital status, number of sexual partners. Co-infection with C. trachomatis and HPV was detected in 2.3% of women with normal cytology, who had 5.1% in ASC-US and 10.4% in those with LSIL. No association was found between infection C. trachomatis and increased risk of HPV infection, but women with simultaneous infection by both pathogens showed greater risk for LSIL. Co-infection was more prevalent among single women, who had in the first sexual intercourse under 18 years and those who had two or more sexual partners over a lifetime

Abordagem de pacientes com úlcera da perna de etiologia venosa

Úlceras venosas são comuns na população adulta, causando significante impacto social e econômico devido a sua natureza recorrente e ao longo tempo decorrido entre sua abertura e cicatrização. Quando não manejadas adequadamente, as úlceras venosas têm altas taxas de falha de cicatrização e recorrência. Apesar da elevada prevalência e da importância da úlcera venosa, ela é freqüentemente negligenciada e abordada de maneira inadequada. Esta revisão discute abordagem diagnóstica e terapêutica das úlceras venosas. O diagnóstico clínico baseia-se em história e exame físico, com ênfase nos sinais e sintomas associados e palpação dos pulsos dos membros inferiores. A ultra-sonografia Doppler deve ser utilizada para determinar o índice pressórico entre o tornozelo e o braço, e exames não invasivos, como o duplex scan, devem ser realizados para avaliar o sistema venoso superficial, profundo e perfurante. Para abordagem terapêutica são fundamentais os diagnósticos clínico e laboratorial corretos, além do diagnóstico e tratamento adequados das complicações das úlceras crônicas. Os esforços devem ser direcionados para a cicatrização da úlcera e, posteriormente, para evitar as recidivas. O grande avanço no conhecimento da fisiopatogenia das úlceras venosas tem permitido o desenvolvimento de novas modalidades de tratamento clínico e cirúrgico.