A systems approach to understand microplastic occurrence and variability in Dutch riverine surface waters

Assessment methods on data quality and environmental variability are lacking for microplastics (MP). Here we assess occurrence and variability of MP number concentrations in two Dutch rivers. Strict QA/QC procedures were applied to identify MP using Fourier-transform infrared (FTIR) microscopy followed by state of the art automated image analysis. For a series of randomly selected, yet ever smaller subareas of filters, we assessed how accurately MP numbers and polymer types are represented during partial filter analysis. Levels of uncertainty were acceptable when analysing 50% of a filter during chemical mapping, and when identifying at least a subset of 50 individual particles with attenuated total reflection (ATR)-FTIR. Applying these guidelines, MP number concentrations between 67 and 11532 MP m^-3 were detected in Dutch riverine surface waters. Spatial differences caused MP number concentrations to vary by two orders of magnitude. Temporal differences were lower and induced a maximum variation of one order of magnitude. In total, 26 polymer types were identified, the most common were polyethylene (23%), polypropylene (19.7%) and ethylene propylene diene monomer rubber (18.3%). The highest diversity of polymer types was found for small MPs, whereas MP larger than 1 mm was scarce and almost exclusively made of polyethylene or polypropylene. Virtually all sampling locations revealed MP number concentrations that are considerably below known effect thresholds for anticipated adverse ecological effects.

No Association between Thrombin Generation and Intra-Plaque Haemorrhage in Symptomatic Carotid Atherosclerotic Plaques: The Plaque at RISK (PARISK) Study

Background Carotid atherosclerosis is an important cause of stroke. Intra-plaque haemorrhage (IPH) on magnetic resonance imaging (MRI) increases stroke risk. Development of IPH is only partly understood. Thrombin is an essential enzyme in haemostasis. Experimental animal studies have shown conflicting results on the relation between thrombin and plaque vulnerability. We hypothesize that decreased thrombin generation (TG) is associated with IPH and plaque vulnerability.

Objective This article investigates whether TG is associated with IPH and other features of plaque vulnerability in stroke patients.

Methods Recently symptomatic stroke patients underwent carotid MRI and blood sampling. MRI plaque features include plaque burden, presence of IPH, amount of lipid-rich necrotic core (LRNC), calcified tissue and fibrous tissue (% of total wall volume). TG was assessed in platelet-poor plasma and expressed as: peak height (PH) and endogenous thrombin potential (ETP). MR images could be analysed in 224 patients. Blood samples were available in 161 of 224 patients. Binary multivariate logistic and linear regression were used to investigate the association between TG and MRI plaque features.

Results IPH and LRNC were present in 65 (40%) and 102 (63%) of plaques. There were no significant associations between TG and IPH; PH odds ratio (OR) = 1, 95% confidence interval (CI): 0.76 to 1.45 and ETP OR = 1, 95% CI: 0.73 to 1.37. After correction for age, sex and hypercholesterolaemia, the association was weak but non-significant; PH: OR = 0.76, 95% CI: 0.52 to 1.10 and ETP: OR = 0.73, 95% CI: 0.53 to 1.37.

Conclusion Features of carotid plaque on MRI show no significant association with TG in stroke patients. Systemic TG does not seem to be an important factor in IPH development.

Surveillance can be the standard of care for stage I nonseminomatous testicular tumors and even high risk patients

PURPOSE

We investigate the results of a surveillance program for stage I nonseminomatous germ cell tumors to validate a surveillance policy, and furthermore improve it by analyzing diagnostic instruments and identifying prognostic factors for relapse.

MATERIALS AND METHODS

From 1982 to 1994, 90 patients with stage I nonseminomatous germ cell tumors entered a surveillance protocol after orchiectomy. Patients with relapse were treated with cisplatin based chemotherapy. A statistical analysis of possible prognostic factors for relapse was performed.

RESULTS

Relapse occurred in 23 (26%) patients. Disease specific survival was 98.9%, and 1 patient died of tumor. Most relapses were located in retroperitoneal lymph nodes only (78%). Tumor markers were the most important indicators of relapse. However, in 22% of patients with relapse abdominal x-ray of lymphangiographic contrast showed the first sign of relapse. Computerized tomography located all but 1 relapse. Vascular invasion (p = 0.0001), tumor size (p = 0.0341) and presence of immature teratoma (p = 0.0154) were significantly predictive of relapse with the multivariate analysis, percentage embryonal carcinoma only by univariate analysis (p = 0.032). The relapse rate was highest (52%) when vascular invasion was present.

CONCLUSIONS

With surveillance for stage I nonseminomatous germ cell tumors, excellent treatment results can be achieved that are comparable to primary retroperitoneal lymph node dissection. Tumor markers and computerized tomography are highly reliable for detecting relapse. Lymphangiography is still of staging value. Pathological factors may influence the choice of adjuvant treatment. However, relapse risks of 50% to 60% are maximally achieved with presently available prognostic factors, and so sparing morbidity of adjuvant treatment by a surveillance protocol remains a feasible option even in these patients.

A multi-center prospective phase II study of high-dose chemotherapy in germ-cell cancer patients relapsing from complete remission

PURPOSE

To prospectively determine the efficacy of repeated high-dose alkylating chemotherapy to salvage patients with germ-cell tumors who relapsed after adequate first-line chemotherapy.

PATIENTS AND METHODS

Patients with germ-cell cancers relapsing from a first, second or third complete remission induced by chemotherapy were offered to participate in a Dutch national prospective trial with broad entry criteria. The salvage treatment began with a conventional dose of ifosfamide (4 g/m2 on day 1) and etoposide (100 mg/m2 on days 1, 2 and 3) followed by daily s.c. administration of G-CSF (10 micrograms/kg) until peripheral blood progenitor cells had been harvested. Immediately after bone marrow recovery, an intermediate dose chemotherapy course of carboplatin (target AUC: 10 mg.ml-1 min on day 1) and etoposide (500 mg/m2 on days 1, 3 and 5) was given with G-CSF daily s.c. After bone marrow recovery, two subsequent courses of high-dose 'CTC' chemotherapy were given, each containing cyclophosphamide (6 g/m2), thiotepa (480 mg/m2) and carboplatin (target AUC: 20 mg.ml-1 min). The high-dose chemotherapy was administered as 30-60-minute infusions, divided over 4 days and the stem-cell transplants were given 48-72 hours after the last chemotherapy infusion. Whenever possible, residual masses were resected at the end of treatment.

RESULTS

Thirty-five patients were treated between January 1994 and October 1997. The toxicity of the treatment was manageable. Second CTC courses were administered in 25 patients and were associated with hemorrhagic cystitis and veno-occlusive disease in 3 and 4 patients, respectively. One patient who had recently undergone a partial hepatectomy, died of veno-occlusive disease. At the time of analysis, the median follow-up of the surviving patients was 37 months (range 12-56 months). The median progression-free survival for all patients was 44 months, and the median overall survival has not been reached. According to the internationally accepted criteria for predicting the outcome of salvage chemotherapy in germ-cell cancer (Beyer et al. J Clin Oncol 1996; 14: 2638-45), 30 patients had 'good risk' criteria. Of these, 29 received high-dose chemotherapy. Of this group, the salvage rate at two years was 65% (95% confidence interval: 49.5%-85.1%).

CONCLUSIONS

Over half of the germ-cell cancer patients relapsing from a chemotherapy-induced complete remission can be salvaged by a treatment strategy that incorporates high-dose chemotherapy, even when treatment is given in a multi-center setting. These data confirm the international prognostic model proposed by Beyer et al. in a prospectively studied, independent patient group and provide further evidence that high-dose therapy has a role in the salvage setting of patients with germ-cell cancer.