DypB peroxidase for aflatoxin removal: New insights into the toxin degradation process

Aflatoxin B1 (AFB1) is one of the most potent carcinogens and a widespread food and feed contaminant. As for other toxins, many efforts are devoted to find efficient and environmentally-friendly methods to degrade AFB1, such as enzymatic treatments, thus improving the safety of food and feed products. In this regard, the dye decolorizing peroxidase of type B (DypB) can efficiently degrade AFB1. The molecular mechanism, which is required to drive protein optimization in view of the usage of DypB as a mycotoxin reduction agent in large scale application, is unknown. Here, we focused on the role of four DypB residues in the degradation of AFB1 by alanine-scanning (residues 156, 215, 239 and 246), which were identified from biochemical assays to be kinetically relevant for the degradation. As a result of DypB degradation, AFB1 is converted into four products. Interestingly, the relative abundancy of these products depends on the replaced residues. Molecular dynamics simulations were used to investigate the role of these residues in the binding step between protein and manganese, a metal ion which is expected to be involved in the degradation process. We found that the size of the haem pocket as well as conformational changes in the protein structure could play a role in determining the kinetics of AFB1 removal and, consequently, guide the process towards specific degradation products.

[The role of electromagnetic navigation bronchoscopy in the diagnosis of peripheral pulmonary lesions]

INTRODUCTION

Electromagnetic navigation bronchoscopy (ENB) is a recent, minimally invasive procedure utilized to guide endoscopic diagnostic tools to peripheral pulmonary nodules. The place of this technology among other diagnostic procedures remains uncertain.

METHOD

We analyzed our 30 first months of ENB used in the diagnosis of 106 lesions in 101 patients, from June 2016 to December 2018. Follow-up and final diagnosis was completed for 95 lesions (90%).

RESULTS

ENB was performed for 3.5% of all patients referred for abnormal findings on pulmonary imaging, and represented 19% of second line procedures for peripheral pulmonary lesions. Procedures were performed under general anesthesia, with a mean duration of 35min. The sensitivity of ENB was 64% (95%CI: 52-74%) for lesions with a mean diameter of 21mm, with an improvement over time (sensitivity 69% in the last 18 months). The presence of a bronchus within the lesion (bronchus sign) was associated with an increased sensitivity of 74%. Pneumothorax occurred in 5 patients (5%) of which 4 required drainage. There was no hemoptysis, and no death related to the procedure.

CONCLUSION

ENB is a minimally invasive procedure reaching acceptable sensitivity in the most difficult patients. ENB can be recommended for the diagnosis of peripheral pulmonary nodules when no other procedure is successful or possible. Its use as a first choice procedure is, for the moment, limited by the cost, but must be weighed against that of non-diagnostic procedures, and the cost of complications of trans-thoracic lung biopsies.

[Endobronchial ultrasonography (EBUS) for the internist]

Endobronchial ultrasonography (EBUS) is a recent mini-invasive technique allowing transbronchial needle aspiration (TBNA) of mediastinal lymph nodes as well as peribronchial lesions. EBUS was initially developed for lung cancer mediastinal staging. Over the years, indications for EBUS have been progressively extended to the scope of inflammatory disorders, mediastinal lymphomas, and infectious diseases. Particularly in immunosuppressed patients, including HIV-infected patients, EBUS allows the diagnosis of several diseases that involve the mediastinum, avoiding invasive surgical explorations such as mediastinoscopy or thoracoscopy. This review aims at discussing the technical aspects, and specifies indications, results, and limits of EBUS for the internist.

[Spontaneous regression of epithelial thymic tumours]

INTRODUCTION

Spontaneous regression of an epithelial thymic tumour has been reported but seems extremely rare. Its mechanism is unknown.

CASE REPORT

We report two cases of epithelial thymic tumour, either histologically proven or highly suspected on imaging, that regressed spontaneously (partially in one patient and totally in the other).

CONCLUSION

Spontaneous regression of an epithelial thymic tumour is very rare but this possibility could lead to clinical and radiological monitoring rather than surgery in selected patients.

Fully endoscopic major pulmonary resection for stage I bronchial carcinoma: initial results

INTRODUCTION

Several case-series studies of major pulmonary resection (MPR) by video-assisted thoracic surgery (VATS) for non-small-cell lung cancer (NSCLC) have been published, but fully endoscopic MPR is still very rarely performed. Our objective here was to report the outcomes in 71 patients recently managed using fully endoscopic MPR for NSCLC.

METHODS

From 2007 to 2009, 635 patients with NSCLC underwent MPR (pneumonectomy, lobectomy or segmentectomy). Among them, 71 (11%) had features strongly suggesting clinical stage I NSCLC and were managed by fully endoscopic MPR, with no utility incision. Lobectomy was performed in 63 patients and segmentectomy in eight patients. Conversion to thoracotomy was required in two (2.8%) patients, because of a fused fissure in one and tight pleural adhesions in the other. Radical lymphadenectomy was performed in all patients.

RESULTS

Of the 69 patients managed endoscopically, none died and none experienced intraoperative complications. Mean operating time was 226±38 minutes (range, 137-307 minutes) and mean intraoperative blood loss was 111±93mL (range, 0-450mL). The final histological examination showed stage I NSCLC in 52 patients, NSCLC with node involvement in nine patients (pN1 in 6 and pN2 in 3) and other types of malignancies in eight patients. Mean number of nodes removed was 21±8 after right-sided lymphadenectomy and 23±8 after left-sided lymphadenectomy and the mean number of dissected node sites was 3 (range, 2-5). The postoperative morbidity rate was 23%. Mean postoperative hospital stay length was 6.9±2 days (range, 3-12).

CONCLUSION

Fully endoscopic MPR is safe and meets the criteria for oncological surgery.

The NER proteins are differentially expressed in ever smokers and in never smokers with lung adenocarcinoma

BACKGROUND

The expression levels of excision repair cross-complementation group 1 (ERCC1), replication protein A (RPA) and xeroderma pigmentosum group F (XPF) nucleotide excision repair proteins may be important in the response to platin-based therapy in lung cancer patients. It is not known whether ERCC1, RPA and XPF expression levels differ between ever smokers (ES) and never smokers (NS).

PATIENTS AND METHODS

ERCC1, RPA and XPF expression levels were immunohistochemically evaluated in 125 patients with resected lung adenocarcinoma (AC) and carefully reviewed smoking status.

RESULTS

ERCC1 was correlated with XPF (P = 0.001), but not with RPA (P = 0.11). In the univariate analysis, ERCC1 and XPF levels were higher in NS compared with ES (P = 0.004 and P = 0.003, respectively). In the multivariate analysis, the smoking status was predictive of the ERCC1 level [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.03-6.2] after adjustment for variables linked to the smoking status, including age and the presence of bronchioloalveolar (BAC) features. The smoking status was also predictive of both RPA (OR 6.7, 95% CI 1.5-33.3) and XPF levels (OR 12.5, 95% CI 2.9-50) after adjusting for age, sex and BAC features.

CONCLUSION

In patients with resected lung AC, ERCC1, RPA and XPF expression levels are higher in NS compared with ES.

Thoracoscopic palliative treatment of malignant pleural effusions

BACKGROUND

The aim of this study was to analyze the results of pleurodesis for malignant pleural effusion performed by surgeons.

PATIENTS AND METHODS

A series of 273 patients with malignant pleural effusion underwent thoracoscopy with the aim of performing a palliative pleurodesis. There were 94 males (34.4%) and 175 females (64.1%), ranging in age from 15 to 94 years (mean age: 60.6 years). The effusion was on the right side in 136 patients (49.8%), on the left side in 110 (40.3%), and bilateral in 27 (9.9%). Thoracoscopy was performed under general anaesthesia in all patients. Pleural biopsy was performed in two thirds of the patients (70.7%). Pleurodesis was produced by instillation of 5g of sterile asbestos-free talc; the chest tube was left in place a minimum of 3 days. It was removed when fluid drainage was less than 200 ml/24 h. Patients were usually discharged the day after chest tube removal.

RESULTS

There was no intraoperative mortality. Two patients (0.7%) had intraoperative complications; 17 (6.2%) underwent a bilateral pleurodesis, and 10 (3.7%) had a pericardiopleural window. In 32 patients (11.7%) no pleurodesis was done, either because the lung did not properly re-expand (5.2%), or because of suspected infection, e.g., false membranes (1.9%), or because of multiple adhesions (4.6%). Finally, only 241 patients (88.3%) had a talc poudrage at the time of thoracoscopy. Duration of postoperative pleural drainage ranged between 1 and 11 days (mean: 3.64 days). The postoperative hospital stay ranged from 2 to 21 days (mean: 7.1 days). Pleural empyema occurred in 4 patients (1.5%) and was lethal in one patient. The mean follow-up period was 8.39 (7.2 months, and 172 patients had regular follow up. In this group, there were 24 recurrences (14%), 12 of which were treated by repeat pleurodesis. The results were very good in 133 patients (77.3%), acceptable in 35 patients (20.3%), and there was a failure in 4 patients (2.4%).

CONCLUSIONS

Results of surgical thoracoscopy for malignant pleural effusion are good, with low morbidity. However, in debilitated patients, bedside talc slurry may be preferable.

Results of thoracoscopic pleural abrasion for primary spontaneous pneumothorax

BACKGROUND

Several video-assisted techniques have been used to treat primary spontaneous pneumothorax (PSP). The aim of this study was to evaluate the results of thoracoscopic pleural abrasion for PSP.

METHODS

From 1991 to 2003, 185 consecutive patients, 143 male and 42 female, aged 15 to 60 years (average 31.6) underwent thoracoscopic pleural abrasion for PSP. The indications for surgery were as follows: a first episode with persistent air leak in 33 patients (17.9%), a recurrent ipsilateral pneumothorax in 122 patients (65.9%), a previous contralateral pneumothorax in 23 patients (12.4%), and recurrence after surgical treatment in seven patients (3.8%). Bullae were resected in 163 patients (88.1%). Mechanical pleural abrasion was performed in all cases.

RESULTS

There were no deaths. Intraoperative hemorrhage occurred in three patients. It was controlled via thoracotomy in one patient and via thoracoscopy in two patients. The postoperative complication rate was 8.1% (15/185). Complications included prolonged air leak in eight patients (4.3%), pleural effusion in two (1.1%), extrapleural hematoma in one (0.5%), chest wall infection in one (0.5%), atelectasis in one (0.5%), and hemorrhage in two (1.1%). Postoperative hospital stay ranged between 2 and 17 days (mean, 5). Mean duration of drainage was 3.8 days (range; 1-16). Postoperatively, 111 patients were contacted, with a mean follow-up of 36.5 months. Four of them had a recurrence (3.6%) that did not require reoperation.

CONCLUSION

Thoracoscopic pleural abrasion associated with bullae resection is a safe and efficient treatment for PSP. Results remain stable in the long term.

[Acute respiratory failure due to Gemcitabine-induced pulmonary toxicity]

Gemcitabine is a therapeutic agent that has been recently employed in the treatment of various cancers. Pulmonary toxicity has rarely been described. We report a case of a patient treated with Gemcitabine who developed acute respiratory symptoms related to a hypersensitivity pneumonia. Despite a severe clinical and radiological presentation, the outcome was favorable with corticosteroid treatment. In the event of respiratory symptoms in patients receiving Gemcitabine further investigations (chest X-ray, thorax CT-scan, bronchoalveolar lavage) are indicated. In view of the severity of pulmonary toxicity that can be caused by Gemcitabine, re-introduction of treatment is not recommended. We compare our case with other published cases of Gemcitabine-induced pulmonary toxicity.

Early complications of thoracic endoscopic sympathectomy: a prospective study of 940 procedures

BACKGROUND

Thoracic endoscopic sympathectomy (TES) has become the surgical technique of choice for treating intractable palmar hyperhidrosis and is usually considered as a simple and safe procedure. To evaluate the complication rate of TES, we conducted a prospective study of peri- and postoperative complications.

METHODS

From 1995 to 1999, 467 consecutive patients were operated on for upper limb hyperhidrosis. There were 164 men and 303 women, ranging in age from 15 to 59 years (mean 31 years). In all but 5 cases, the procedure was bilateral. Eleven patients underwent a reoperation for failure; thus the total number of sympathectomies was 940. The procedure was performed in two stages in 182 patients and in one stage in 267 patients. All patients were seen 1 month after the operation.

RESULTS

There was no mortality. The mean postoperative hospital stay was 2.3 days in the group of patients who were operated on in two stages and 1.1 day in patients who were operated on in one stage. There were three major complications: one tear of the right subclavian artery and two chylothoraces. There were 25 cases (5.3%) of bleeding (300 to 600 mL) during dissection of the sympathetic trunk due to injury to an intercostal vein; in all cases it was controlled thoracoscopically. There were 12 pneumothoraces (1.3%) after removal of chest tubes. All of these were unilateral. Four required chest drainage for a period of less than 24 hours. One patient had a mild pleural effusion. Four patients had a unilateral partial Horner Syndrome (0.4%) that disappeared within 3 months in 2 patients. The other 2 patients were lost to follow-up. One patient complained of rhinitis.

CONCLUSIONS

Although morbidity was low, significant complications of TES occurred. Patients should be clearly warned that TES is not as minor a procedure as usually asserted. Complications as well as adverse effects should be considered when discussing this surgical indication.

[Mediastioscopic management of pleuropericardial cysts]

We report two cases of paratracheal cystic tumors where no preoperative diagnosis could be established. Mediastinoscopy provided the diagnosis of pleuropericardial cyst. The mediastinoscopic approach allowed partial removal in one case and complete removal in the other.

Combination raltitrexed (Tomudex(R))-oxaliplatin: a step forward in the struggle against mesothelioma? The Institut Gustave Roussy experience with chemotherapy and chemo-immunotherapy in mesothelioma

The aim of this study was to review the experience of the Institut Gustave Roussy in 163 patients with malignant mesothelioma over a 9-year period. Data from seven consecutive prospective trials, four of chemo-immunotherapy and three of chemotherapy were reviewed. The rationale, methods and results of these trials are summarised and discussed. 98 patients were included in four phase II trials of chemo-immunotherapy whose common denominator was a combination of cisplatin and alpha-interferon. The response rate ranged from 15% to 40%. High-dose weekly cisplatin combined with alpha-interferon yielded the highest response rate but the toxicity of this regimen was considered unacceptable. Neither higher doses of alpha-interferon or the addition of mitomycin C or interleukin-2 to the regimen were able to enhance the activity of this combination. 18 patients were included in a paclitaxel-cisplatin phase II trial. The response rate was only 6% (95% confidence interval (CI): 0-24) and toxicity was also significant. This regimen was, therefore, considered ineffective. Of 17 patients with mesothelioma included in a phase I trial that combined raltitrexed and oxaliplatin, 6 (35%) obtained a partial response. Responses were seen even in cisplatin-refractory mesothelioma. Preliminary results of a subsequent ongoing phase II trial using raltitrexed (3 mg/m(2)) and oxaliplatin (130 mg/m(2)) have confirmed this promising activity with a 30% (9/30) response rate (95% CI: 15-49). The tolerance of this outpatient regimen is acceptable (no significant haematological toxicity and no alopecia) and compares favourably with that of our previous regimens. The final results concerning response and survival are required to confirm the efficacy of this combination. The preliminary results of two studies suggest promising activity with the combination of raltitrexed-oxaliplatin in malignant mesothelioma. The efficacy/toxicity ratio of this combination compares favourably with that of our previous chemotherapy and chemo-immunotherapy regimens.

[Primary biphasic synovial sarcoma of the pleura]

A 36-year-old man presented with a pleural tumor. The first pathologic analysis diagnosed biphasic pleural malignant mesothelioma. However, the atypical clinical course, the early development of lung metastases and a new reading of histologic documents led to the diagnosis of primary pleural synovial sarcoma. The literature review is limited, as only nine other cases have been reported to date. Chest pain is the only constant clinical feature. Misleading interpretation of histologic material is frequent (6 of 10 cases). Only a complete immuno-histochemical study confronted with the clinical course can lead to the correct diagnosis. Because the efficacy of chemotherapy and/or radiotherapy is poor, surgery remains the basis of treatment, whenever possible. Evolution is mainly intra-thoracic, with multiple local recurrences and lung metastases. Prognostic is poor, a survival rate is similar to that of primary pulmonary sarcomas.

Curative irradiation of limited endobronchial carcinomas with high-dose rate brachytherapy. Results of a pilot study

OBJECTIVES OF THE STUDY

Pilot study to assess high-dose rate (HDR) brachytherapy as sole treatment for limited endobronchial non-small cell lung carcinomas.

INCLUSION CRITERIA

Proximal non-small cell lung cancer in a not previously irradiated area, with a maximal diameter of 1 cm, no visible tumor on CT scan, lack of other treatment options in patients with severe, chronic respiratory failure, surgery, or external radiotherapy for a previous lung cancer.

TREATMENT PROTOCOL

Treatment was based on an escalating dose protocol. Patients received three to five fractions of 7 Gy prescribed at 10 mm from the center of the applicator, once a week.

RESULTS

Nineteen patients were included in this trial. The first two patients received three fractions of 7 Gy, the four next patients received four fractions, and the 13 remaining patients were treated with five fractions of 7 Gy. Two months after the end of the procedure, tumors in 15 of 18 evaluable patients (83%) were locally controlled with negative results of biopsies. At 1 year, local control was still obtained in 12 of 16 evaluable patients (75%). With a mean follow-up of 28-months, 1-year and 2-year actuarial survival rates were 78% and 58%, respectively, with a 28-month median survival. One patient with local control died from hemoptysis 12 months after treatment. Two patients suffered from severe necrosis of the bronchial wall; one of them died from hemoptysis.

CONCLUSIONS

HDR brachytherapy is an effective treatment for small endobronchial tumors. Late toxicity on the bronchial wall is still too high and was attributed mainly to contact between the catheter and the bronchial mucosa. Exclusive HDR brachytherapy should be restricted to carefully selected patients for whom there is no alternative curative treatment. New bronchial applicators and a lower dose per fraction may reduce the incidence and attenuate the severity of late complications.

[Condylomata acuminata of the external genitalia and dysplasia of the uterine cervix]

Condylomata acuminata of the external genitalia and dysplasias of the uterine cervix The prevalence of cervical abnormalities indicative of papillomavirus infection and/or dysplasia was evaluated in a group of women previously treated for vulvar condylomata acuminata. The results obtained seem to demonstrate that the women affected by vulvar condylomata acuminata are particularly exposed to the risk of acquiring slight or moderate grade dysplasias. However, the lack of severe dysplasias in our patients tends to suggest that cervical dysplasias associated to vulvar condylomata acuminata are characterized by a poor inclination towards neoplastic evolution.