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Background: Household contact investigation (HCI) is an effective and widely used approach to identify persons with tuberculosis (TB) disease and infection, globally. Despite widespread recommendations for the use of HCI, there remains poor understanding of the impact on and value of contact investigation for participants. Further, how HCI as a practice impacts psychosocial factors, including stigma and possible unintended disclosure of illness among persons with TB, their families, and communities, is largely unknown. Methods: This exploratory qualitative study nested within a randomized trial (ClinicalTrials.gov: NCT04520113, 17 August 2020) was conducted in South Africa to understand the impacts of HCI on index patients living with TB and their household contact persons in two rural districts in the Limpopo province (Vhembe and Capricorn) and Soshanguve, a peri-urban township in Gauteng province. People with TB and household members of people with TB were recruited to participate in in-depth interviews and focus group discussions using semi-structured guides. We explored individual, interpersonal, and community-level perceptions of potential impacts of household contact investigation to elucidate their perceptions of HCI. Thematic analysis identified key themes. Results: Twenty-four individual interviews and six focus group discussions (n=39 participants) were conducted. Participants viewed HCI as an effective approach to finding TB cases, helpful in educating households about TB symptoms and reducing barriers to health-related services. At the interpersonal level, HCI aided people with TB in safely disclosing their TB status to family members and facilitated family and social support for accountability. The introduction of HIV testing during HCI was reported by some participants as making household members slightly uncomfortable, decreasing interest in household members being tested for TB. HCI negatively impacted community-level TB and HIV-related stigma due to healthcare worker visibility at home. Conclusion: Our data suggests varying impacts of HCI on people with TB, their families and interpersonal relationships, and communities, highlighting the importance of considering approaches that address concerns about community stigma and HIV testing to enhance acceptance of HCI.
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BACKGROUND: Stroma AReactive Invasion Front Areas (SARIFA) is a novel prognostic histopathologic biomarker measured at the invasive front in haematoxylin & eosin (H&E) stained colon and gastric cancer resection specimens. The aim of the current study was to validate the prognostic relevance of SARIFA-status in colorectal cancer (CRC) patients and investigate its association with the luminal proportion of tumour (PoT). METHODS: We established the SARIFA-status in 164 CRC resection specimens. The relationship between SARIFA-status, clinicopathological characteristics, recurrence-free survival (RFS), cancer-specific survival (CSS), and PoT was investigated. RESULTS: SARIFA-status was positive in 22.6% of all CRCs. SARIFA-positivity was related to higher pT, pN, pTNM stage and high grade of differentiation. SARIFA-positivity was associated with shorter RFS independent of known prognostic factors analysing all CRCs (RFS: hazard ratio (HR) 2.6, p = 0.032, CSS: HR 2.4, p = 0.05) and shorter RFS and CSS analysing only rectal cancers. SARIFA-positivity, which was measured at the invasive front, was associated with PoT-low (p = 0.009), e.g., higher stroma content, and lower vessel density (p = 0.0059) measured at the luminal tumour surface. CONCLUSION: Here, we validated the relationship between SARIFA-status and prognosis in CRC patients and provided first evidence for a potential prognostic relevance in the subgroup of rectal cancer patients. Interestingly, CRCs with different SARIFA-status also showed histological differences measurable at the luminal tumour surface. Further studies to better understand the relationship between high luminal intratumoural stroma content and absence of a stroma reaction at the invasive front (SARIFA-positivity) are warranted and may inform future treatment decisions in CRC patients.
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AIM: The optimum surgical approach to splenic flexure cancers (SFCs) remains uncertain. The aim of this survey was to explore the opinions of an international surgical community on the management and outcomes of SFC. METHOD: A questionnaire was constructed comprising five sections (information about respondents; definition and prognosis of SFC; operative approach; approach in specific scenarios; outcomes) and circulated through an international dissemination committee and social media. RESULTS: The survey received 576 responses over 4 weeks across 50 countries. There was no consensus regarding the definition of the splenic flexure, whilst the proportion of respondents who did and did not think that patients with SFC had a worse outcome was equal. The overall preferred operative approach was left hemicolectomy [203 (35.2%)], followed by segmental resection [167 (29%)], extended right hemicolectomy [126 (21.9%)] and subtotal colectomy [7 (12%)]. The stated pedicles for ligation varied between resection types and also within the same resection. One hundred and sixty-six (28.8%) respondents thought a segmental resection was associated with the worst survival and 190 (33%) thought it was associated with the best quality of life. CONCLUSION: This survey confirms a lack of consensus across all aspects SFC treatment. The differing approaches described are likely to represent different beliefs around the variable anatomy of this region and the associated lymphatic drainage. Future studies are required to address such inconsistencies and identify the optimum surgical strategy, whilst also incorporating quality-of-life metrics and patient-reported outcomes. A one-size-fits-all approach is probably not appropriate with SFC, and a more bespoke approach is required.
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Colectomia , Colo Transverso , Neoplasias Colorretais , Humanos , Colectomia/métodos , Colo Transverso/cirurgia , Inquéritos e Questionários , Neoplasias Colorretais/cirurgia , Neoplasias Colorretais/patologia , Masculino , Feminino , Resultado do Tratamento , Pessoa de Meia-Idade , Prognóstico , IdosoRESUMO
Introduction: The bottlenose dolphin (Tursiops truncatus) is an intermittent breather, where the breath begins with an exhalation followed by inhalation and an extended inter-breath interval ranging from 10 to 40 s. Breathing has been shown to alter both the instantaneous heart rate (if H) and stroke volume (iSV) in the bottlenose dolphin, with a transitory ventilatory tachycardia following the breath, and an exponential decrease to a stable if H around 40 beats ⢠min-1 during the inter-breath period. As the total breath duration in the dolphin is around 1 s, it is not possible to assess the contribution of exhalation and inhalation to these changes in cardiac function during normal breathing. Methods: In the current study, we evaluated the if H response by separating expiration and inspiration of a breath, which allowed us to distinguish their respective contribution to the changes in if H. We studied 3 individual male bottlenose dolphins trained to hold their breath between the different respiratory phases (expiration and inhalation). Results: Our data show that inspiration causes an increase in if H, while expiration appears to result in a decrease in if H. Discussion: These data provide improved understanding of the cardiorespiratory coupling in dolphins, and show how both exhalation and inhalation alters if H.
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BACKGROUND: TB-related stigma hampers access to diagnosis and treatment, making it important to understand the demographic and clinical characteristics associated with perceived TB stigma. TB stigma has not been studied in household contacts before, yet they comprise an important population for epidemic control, with high risk of infection.METHOD: A cross-sectional study was conducted among people with TB and household contacts in South Africa using a 12-item perceived TB stigma scale (score range: 0-36). Demographic and clinical characteristic data were collected using a close-ended questionnaire. A linear mixed-effects regression model was used to explore perceived TB stigma levels and its associated characteristics.RESULTS: The sample included 143 people with TB and 135 household contacts. The mean perceived TB stigma score among people with TB was 22.1 (95% CI 21.1-23.1) and 22.2 (95% CI 21.1-23.3) among household contacts. Being in the same household explained 24.3% variability in stigma perception. Residence in the urban study site (Soshanguve) and a positive HIV diagnosis were associated with higher perceived TB stigma score.CONCLUSIONS: People with TB and household contacts have similarly high prevalence of perceived TB stigma. Positive HIV status and urban location were associated with higher prevalence of perceived TB stigma.
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Epidemias , Soropositividade para HIV , Tuberculose , Humanos , Estudos Transversais , Tuberculose/diagnóstico , Tuberculose/epidemiologia , Modelos LinearesRESUMO
AIMS: Osteoradionecrosis (ORN) is a serious toxicity of head and neck radiotherapy. It predominantly affects the mandible. Extra-mandibular ORN is rare. The aim of this study was to report the incidence and outcomes of extra-mandibular ORNs from a large institutional database. MATERIALS AND METHODS: In total, 2303 head and neck cancer patients were treated with radical or adjuvant radiotherapy. Of these, extra-mandibular ORN developed in 13 patients (0.5%). RESULTS: Maxillary ORNs (n = 8) were a consequence of the treatment of various primaries (oropharynx = 3, sinonasal = 2, maxilla = 2, parotid = 1). The median interval from the end of radiotherapy to the development of ORN was 7.5 months (range 3-42 months). The median radiotherapy dose in the centre of the ORN was 48.5 Gy (range 22-66.5 Gy). Four patients (50%) healed in 7, 14, 20 and 41 months. All temporal bone ORNs (n = 5) developed after treatment to the parotid gland (of a total of 115 patients who received radiotherapy for parotid gland malignancy). The median interval from the end of radiotherapy to the development of ORN was 41 months (range 20-68 months). The median total dose in the centre of the ORN was 63.5 Gy (range 60.2-65.3 Gy). ORN healed in only one patient after 32 months of treatment with repeated debridement and topical betamethasone cream. CONCLUSION: Extra-mandibular ORN is a rare late toxicity and this current study provides useful information on its incidence and outcome. The risk of temporal bone ORN should be considered in the treatment of parotid malignancies and patients should be counselled. More research is required to determine the optimal management of extra-mandibular ORN, particularly on the role of the PENTOCLO regimen.
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Neoplasias de Cabeça e Pescoço , Doenças Mandibulares , Osteorradionecrose , Humanos , Estudos Retrospectivos , Osteorradionecrose/epidemiologia , Osteorradionecrose/etiologia , Dosagem Radioterapêutica , Doenças Mandibulares/complicações , Doenças Mandibulares/epidemiologia , Neoplasias de Cabeça e Pescoço/radioterapia , MandíbulaRESUMO
BACKGROUND: Cystic fibrosis (CF) pulmonary exacerbation (PEx) treatment guidelines suggest that Pseudomonas aeruginosa (Pa) airway infection be treated with two antipseudomonal agents. METHODS: We retrospectively studied treatment responses for STOP2 PEx treatment trial (NCT02781610) participants with a history of Pa infection. Mean lung function and symptom changes from intravenous (IV) antimicrobial treatment start to Visit 2 (7 to 10 days later) were compared between those receiving one, two, and three+ antipseudomonal classes before Visit 2 by ANCOVA. Odds of PEx retreatment with IV antimicrobials within 30 days and future IV-treated PEx hazard were modeled by logistic and Cox proportional hazards regression, respectively. Sensitivity analyses limited to the most common one-, two-, and three-class regimens, to only IV/oral antipseudomonal treatments, and with more stringent Pa infection definitions were conducted. RESULTS: Among 751 participants, 50 (6.7%) were treated with one antipseudomonal class before Visit 2, while 552 (73.5%) and 149 (19.8%) were treated with two and with three+ classes, respectively. Females and participants with a negative Pa culture in the prior month were more likely to be treated with a single class. The most common single, double, and triple class regimens were beta-lactam (BL; n = 42), BL/aminoglycoside (AG; n = 459), and BL/AG/fluoroquinolone (FQ; n = 73). No lung function or symptom response, odds of retreatment, or future PEx hazard differences were observed by number of antipseudomonal classes administered in primary or sensitivity analyses. CONCLUSIONS: We were unable to identify additional benefit when multiple antipseudomonal classes are used to treat PEx in people with CF and Pa.
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Fibrose Cística , Infecções por Pseudomonas , Aminoglicosídeos , Antibacterianos , Fibrose Cística/complicações , Fibrose Cística/diagnóstico , Fibrose Cística/tratamento farmacológico , Feminino , Fluoroquinolonas , Humanos , Infecções por Pseudomonas/diagnóstico , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa , Estudos Retrospectivos , beta-LactamasRESUMO
BACKGROUND: Microsatellite instability (MSI)/mismatch repair deficiency (dMMR) is a key genetic feature which should be tested in every patient with colorectal cancer (CRC) according to medical guidelines. Artificial intelligence (AI) methods can detect MSI/dMMR directly in routine pathology slides, but the test performance has not been systematically investigated with predefined test thresholds. METHOD: We trained and validated AI-based MSI/dMMR detectors and evaluated predefined performance metrics using nine patient cohorts of 8343 patients across different countries and ethnicities. RESULTS: Classifiers achieved clinical-grade performance, yielding an area under the receiver operating curve (AUROC) of up to 0.96 without using any manual annotations. Subsequently, we show that the AI system can be applied as a rule-out test: by using cohort-specific thresholds, on average 52.73% of tumors in each surgical cohort [total number of MSI/dMMR = 1020, microsatellite stable (MSS)/ proficient mismatch repair (pMMR) = 7323 patients] could be identified as MSS/pMMR with a fixed sensitivity at 95%. In an additional cohort of N = 1530 (MSI/dMMR = 211, MSS/pMMR = 1319) endoscopy biopsy samples, the system achieved an AUROC of 0.89, and the cohort-specific threshold ruled out 44.12% of tumors with a fixed sensitivity at 95%. As a more robust alternative to cohort-specific thresholds, we showed that with a fixed threshold of 0.25 for all the cohorts, we can rule-out 25.51% in surgical specimens and 6.10% in biopsies. INTERPRETATION: When applied in a clinical setting, this means that the AI system can rule out MSI/dMMR in a quarter (with global thresholds) or half of all CRC patients (with local fine-tuning), thereby reducing cost and turnaround time for molecular profiling.
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Neoplasias Colorretais , Instabilidade de Microssatélites , Inteligência Artificial , Neoplasias Colorretais/diagnóstico , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Reparo de Erro de Pareamento de DNA/genética , Detecção Precoce de Câncer , HumanosRESUMO
BACKGROUND: In the STOP2 (Standardized Treatment of Pulmonary Exacerbations-2) study, intravenous (IV) antimicrobial treatment duration for adults with cystic fibrosis (CF) experiencing pulmonary exacerbations (PEx) was determined based on initial treatment response. The impact of home vs hospital care remains an important clinical question in CF. Our hypothesis was that STOP2 participants treated at home would have less improvement in lung function compared to those treated in the hospital. METHODS: Treating clinicians determined PEx treatment location, which was a stratification factor for STOP2 randomization. Lung function, weight, and symptom recovery were evaluated by treatment location. Propensity scores and inverse probability treatment weighting were used to test for differences in clinical response by treatment location. RESULTS: In all, 33% of STOP2 participants received IV antimicrobials in the hospital only, 46% both in the hospital and at home, and 21% at home only. Mean (95% CI) ppFEV1 improvement was significantly (p < 0.05) lower for those treated at home only, 5.0 (3.5, 6.5), compared with at home and in the hospital, 7.0 (5.9, 8.1), and in the hospital only, 8.0 (6.7, 9.4). Mean weight (p < 0.001) and symptom (p < 0.05) changes were significantly smaller for those treated at home only compared to those treated in the hospital only. CONCLUSIONS: Compared to PEx treatment at home only, treatment in the hospital was associated with greater mean lung function, respiratory symptom, and weight improvements. The limitations of home IV therapy should be addressed in order to optimize outcomes for adults with CF treated at home.
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Anti-Infecciosos , Fibrose Cística , Administração Intravenosa , Adulto , Antibacterianos , Anti-Infecciosos/uso terapêutico , Fibrose Cística/complicações , Fibrose Cística/diagnóstico , Fibrose Cística/tratamento farmacológico , Humanos , PulmãoRESUMO
BACKGROUND: C-reactive protein (CRP) has been proposed as a biomarker for pulmonary exacerbation (PEx) diagnosis and treatment response. CRP >75mg/L has been associated with increased risk of PEx treatment failure. We have analyzed CRP measures as biomarkers for clinical response during the STOP2 PEx study (NCT02781610). METHODS: CRP measures were collected at antimicrobial treatment start (V1), seven to 10 days later (V2), and two weeks after treatment end (V3). V1 log10CRP concentrations and log10CRP change from V1 to V3 correlations with clinical responses (changes in lung function and symptom score) were assessed by least squares regression. Odds of intravenous (IV) antimicrobial retreatment within 30 days and future PEx hazard associated with V1 and V3 CRP concentrations and V1 CRP >75 mg/L were studied by adjusted logistic regression and proportional hazards modeling, respectively. RESULTS: In all, 951 of 982 STOP2 subjects (92.7%) had CRP measures at V1. V1 log10CRP varied significantly by V1 lung function subgroup, symptom score quartile, and sex, but not by age subgroup. V1 log10CRP correlated moderately with log10CRP change at V3 (r2=0.255) but less so with lung function (r2=0.016) or symptom (r2=0.031) changes at V3. Higher V1 CRP was associated with greater response. CRP changes from V1 to V3 only weakly correlated with lung function (r2=0.061) and symptom (r2=0.066) changes. However, V3 log10CRP was associated with increased odds of retreatment (P = .0081) and future PEx hazard (P = .0114). DISCUSSION: Despite consistent trends, log10CRP change was highly variable with only limited utility as a biomarker of PEx treatment response.
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Anti-Infecciosos , Fibrose Cística , Antibacterianos , Anti-Infecciosos/uso terapêutico , Biomarcadores , Proteína C-Reativa , Humanos , PulmãoRESUMO
Mental health impacts of the COVID-19 pandemic for people living with HIV are poorly understood, especially in low-income settings. We conducted qualitative semi-structured in-depth interviews among people living with HIV (n = 16) and health workers (n = 10) in rural Rakai, southcentral Uganda. Data were analyzed thematically. We found mental stress during COVID-19 was compounded by worry about antiretroviral therapy (ART) access, distress over inadvertent disclosure of HIV status, fear that coronavirus infection would have more severe outcomes for immunocompromised individuals, and exacerbated poverty and economic stress. Mental health support for people living with HIV deserves greater attention during the COVID-19 pandemic and beyond.
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COVID-19 , Infecções por HIV , Infecções por HIV/tratamento farmacológico , Infecções por HIV/epidemiologia , Humanos , Saúde Mental , Pandemias , SARS-CoV-2 , Uganda/epidemiologiaRESUMO
The focus on lymph node metastases (LNM) as the most important prognostic marker in colorectal cancer (CRC) has been challenged by the finding that other types of locoregional spread, including tumor deposits (TDs), extramural venous invasion (EMVI), and perineural invasion (PNI), also have significant impact. However, there are concerns about interobserver variation when differentiating between these features. Therefore, this study analyzed interobserver agreement between pathologists when assessing routine tumor nodules based on TNM 8. Electronic slides of 50 tumor nodules that were not treated with neoadjuvant therapy were reviewed by 8 gastrointestinal pathologists. They were asked to classify each nodule as TD, LNM, EMVI, or PNI, and to list which histological discriminatory features were present. There was overall agreement of 73.5% (κ 0.38, 95%-CI 0.33-0.43) if a nodal versus non-nodal classification was used, and 52.2% (κ 0.27, 95%-CI 0.23-0.31) if EMVI and PNI were classified separately. The interobserver agreement varied significantly between discriminatory features from κ 0.64 (95%-CI 0.58-0.70) for roundness to κ 0.26 (95%-CI 0.12-0.41) for a lone arteriole sign, and the presence of discriminatory features did not always correlate with the final classification. Since extranodal pathways of spread are prognostically relevant, classification of tumor nodules is important. There is currently no evidence for the prognostic relevance of the origin of TD, and although some histopathological characteristics showed good interobserver agreement, these are often non-specific. To optimize interobserver agreement, we recommend a binary classification of nodal versus extranodal tumor nodules which is based on prognostic evidence and yields good overall agreement.
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Extensão Extranodal/patologia , Patologistas , Neoplasias Retais/patologia , Biópsia , Competência Clínica , Ensaios Clínicos como Assunto , Inglaterra , Humanos , Metástase Linfática , Estadiamento de Neoplasias , Variações Dependentes do Observador , Valor Preditivo dos Testes , Neoplasias Retais/classificação , Reprodutibilidade dos Testes , Estudos RetrospectivosRESUMO
BACKGROUND: Laparoscopic complete mesocolic excision (CME) of the right colon with central vascular ligation (CVL) is a technically demanding procedure. This study retrospectively evaluated the feasibility, safety and oncological outcomes of the procedure when performed using the da Vinci® robotic system. METHODS: A prospective case series was collected over 3 years for patients with right colonic cancers treated by standardized robotic CME with CVL using the superior mesenteric vessels first approach. The CME group was compared to a 2 : 1 propensity score-matched non-CME group who had conventional laparoscopic right colectomy with D2 nodal dissection. Primary outcomes were total lymph node harvest and length of specimen. Secondary outcomes were operative time, postoperative complications, and disease-free and overall survival. RESULTS: The study included 120 patients (40 in the CME group and 80 in the non-CME group). Lymph node yield was higher (29 versus 18, P = 0.006), the specimen length longer (322 versus 260 mm, P = 0.001) and median operative time was significantly longer (180 versus 130 min, P < 0.001) with robotic CME versus laparoscopy, respectively. Duration of hospital stay was longer with robotic CME, although not significantly (median 6 versus 5 days, P = 0.088). There were no significant differences in R0 resection rate, complications, readmission rates and local recurrence. A trend in survival benefit with robotic CME for disease-free (P = 0.0581) and overall survival (P = 0.0454) at 3 years was documented. CONCLUSION: Robotic CME with CVL is feasible and, although currently associated with a longer operation time, it provides good specimen quality, higher lymph node yield and acceptable morbidity, with a disease-free survival advantage.
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Colectomia/métodos , Neoplasias do Colo/cirurgia , Laparoscopia , Mesocolo/cirurgia , Procedimentos Cirúrgicos Robóticos , Adulto , Idoso , Idoso de 80 Anos ou mais , Neoplasias do Colo/mortalidade , Feminino , Humanos , Tempo de Internação/estatística & dados numéricos , Ligadura , Excisão de Linfonodo , Linfonodos/patologia , Masculino , Pessoa de Meia-Idade , Duração da Cirurgia , Complicações Pós-Operatórias , Pontuação de Propensão , Estudos Retrospectivos , Análise de SobrevidaRESUMO
INTRODUCTION: Symptom improvement was assessed as changes in the Chronic Respiratory Infection Symptom Score (CRISS) during intravenous antimicrobial exacerbation treatments among subjects from study NCT02109822. METHODS: Median daily CRISS reduction (i.e., improvement) and covariates associated with CRISS reduction by Day 14 were assessed by logistic regression. RESULTS: Among 173 subjects, median baseline CRISS was 49 [IQR 41, 56]; 93.6% had a CRISS reduction of ≥11 (minimal clinically important difference); median time to -11 reduction was 2 days [95% CI 2, 3]. The greatest median CRISS difference from baseline, on Day 17, was -26 [-29, -23]. Odds of -26 CRISS change by Day 14 were greater in subjects with higher baseline CRISS (P=.006) and younger ages (P=.041). CONCLUSIONS: CRISS response has good dynamic range and may be a useful efficacy endpoint for PEx interventional trials. The optimal use of CRISS change as an endpoint remains uncharacterized.
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Antibacterianos/uso terapêutico , Fibrose Cística/complicações , Progressão da Doença , Infecções Respiratórias/complicações , Infecções Respiratórias/tratamento farmacológico , Avaliação de Sintomas/métodos , Adolescente , Adulto , Doença Crônica , Ensaios Clínicos como Assunto , Humanos , Infecções Respiratórias/diagnóstico , Adulto JovemRESUMO
Endoluminal surgery for the treatment of colorectal neoplasia is typically carried out using electrocautery tools which imply limited precision and the risk of harm through collateral thermal damage to the adjacent healthy tissue. As a potential alternative, we present the successful colonic epithelial laser ablation by means of picosecond laser pulses. Laser ablation studies performed in ex-vivo colon tissue result in cavities with comparable thickness to early stage colorectal cancers. The corresponding histology sections exhibit only minimal collateral damage to the surrounding tissue and the depth of the ablation can be controlled precisely by means of the pulse energy. High-speed imaging has been used for the first time to visualize picosecond laser ablation of cancerous tissue in a clinically relevant model. This information was correlated with histopathology and optical surface profilometry revealing the dynamic nature of the laser tissue interaction and the need for temporal or spatial separation of pulses for optimum efficacy with regards to tissue removal. Overall, the application of picosecond laser pulses to ablate endoluminal bowel lesions demonstrates significantly improved precision and reduced thermal damage to the adjacent tissue in comparison to conventional procedures and hence will enable more precise surgical treatment of cancers.
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Neoplasias Colorretais/cirurgia , Terapia a Laser , Animais , Modelos Animais de Doenças , Camundongos , SuínosRESUMO
BACKGROUND: Avène Thermal Spring Water (TSW) exhibits therapeutic properties in the treatment of skin pathologies. Arising from a dolomitic aquifer system, its physico-chemical properties are well-established and its bacteriological quality regularly monitored. The microbiota of this aquifer have been characterized. OBJECTIVES: We aimed to describe the structure of the bacterial community inhabiting the deep aquifer and to examine its dynamics over time. METHODS: The Avène TSW was collected at the catchment point and filtered through 0.1 µm pore size filters. The sampling was carried out every 3 months to generate a 4-year time series. The DNA extracted from filters was analysed using high-throughput 16S rRNA gene amplicon sequencing, and the microorganisms and their contribution were characterized by the taxonomic assignment of sequence variants generated from each sample. RESULTS: Bacteria were distributed into 39 phyla. Nitrospirae and Proteobacteria were the most prevalent, accounting for 38% and 23% of the total community on average, respectively. A stable pattern was observed throughout the study. A few bacterial species were always detected, forming a core community of likely chemolithoautotrophic organisms which might use energy sources and nutrients produced from water-bedrock interactions. Most of the species were distantly related to organisms described to date. CONCLUSIONS: Avène TSW provided by the deep aquifer system harbours a unique microbial community, shaped by the physico-chemical characteristics of the deep environment. Its remarkable stability over time has revealed a high level of confinement of the water resource.
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Fontes Termais , Microbiota , Bactérias/genética , Humanos , RNA Ribossômico 16S/genética , ÁguaRESUMO
Microorganisms are an important component in shaping the evolution of hosts and as such, the study of bacterial communities with molecular techniques is shedding light on the complexity of symbioses between bacteria and vertebrates. Teleost fish are a heterogeneous group that live in a wide variety of habitats, and thus a good model group to investigate symbiotic interactions and their influence on host biology and ecology. Here we describe the microbiota of thirteen teleostean species sharing the same environment in the Mediterranean Sea and compare bacterial communities among different species and body sites (external mucus, skin, gills, and intestine). Our results show that Proteobacteria is the dominant phylum present in fish and water. However, the prevalence of other bacterial taxa differs between fish and the surrounding water. Significant differences in bacterial diversity are observed among fish species and body sites, with higher diversity found in the external mucus. No effect of sampling time nor species individual was found. The identification of indicator bacterial taxa further supports that each body site harbors its own characteristic bacterial community. These results improve current knowledge and understanding of symbiotic relationships among bacteria and their fish hosts in the wild since the majority of previous studies focused on captive individuals.