Calculation of internal dose from ingested soil-derived uranium in humans: Application of a new method.

The aim of the present study was to determine the internal dose in humans after the ingestion of soil highly contaminated with uranium. Therefore, an in vitro solubility assay was performed to estimate the bioaccessibility of uranium for two types of soil. Based on the results, the corresponding bioavailabilities were assessed by using a recently published method. Finally, these bioavailability data were used together with the biokinetic model of uranium to assess the internal doses for a hypothetical but realistic scenario characterized by a daily ingestion of 10 mg of soil over 1 year. The investigated soil samples were from two former uranium mining sites of Germany with (238)U concentrations of about 460 and 550 mg/kg. For these soils, the bioavailabilities of (238)U were quantified as 0.18 and 0.28 % (geometric mean) with 2.5th percentiles of 0.02 and 0.03 % and 97.5th percentiles of 1.48 and 2.34 %, respectively. The corresponding calculated annual committed effective doses for the assumed scenario were 0.4 and 0.6 µSv (GM) with 2.5th percentiles of 0.2 and 0.3 µSv and 97.5th percentiles of 1.6 and 3.0 µSv, respectively. These annual committed effective doses are similar to those from natural uranium intake by food and drinking water, which is estimated to be 0.5 µSv. Based on the present experimental data and the selected ingestion scenario, the investigated soils-although highly contaminated with uranium-are not expected to pose any major health risk to humans related to radiation.

[Percutaneous endoscopic gastrostomy in patients with ENT tumors]. / PEG-Anlage bei Patienten mit HNO-Tumoren.

Oral food intake in patients with obstructing pharyngeal and esophageal carcinomas is commonly insufficient because of tumor-induced dysphagia which gives rise to cachexia unless treated. While entailing an unfavorable prognosis, malnutrition is often a therapy-limiting factor. Tube feeding with liquid formula diets currently offers the most efficient and least-risky approach to long-term use and is best adopted even at a pretreatment stage irrespective of the tumor therapy intended. A feeding tube placed by a percutaneous endoscopically controlled gastrostomy (PEG) increasingly offers an alternative to a nasogastric tube. After using diaphanoscopy, the stomach is punctured from outside under local anesthesia and a feeding tube inserted by means of a retrograde thread or a direct puncture method. A modification of the direct puncture method has been preferred at the Magdeburg University E.N.T. Department. The tube is held in place by thermally activated helical winding of a gastric tube end (using a memory-retaining helix). During the 1991-1996 period 415 patients with obstructing carcinomas of the upper digestive tract were treated with a feeding tube. No fatal complications were observed. Severe complications (peritonitis) occurred in three patients. In 160 patients with PEG the following parameters were recorded: weight-to-size index, body mass index, degree of dysphagia, nutrition status, lymphocyte count, total serum protein and patients' compliance to PEG. The enteral nutrition therapy used was indicated in all of the patients treated with advanced carcinomas of the head and neck. In 81% of the patients the compliance to PEG was positive. Findings demonstrated that long-term intestinal nutrition via PEG was a safe and effective form of treatment. Inserting the tube by the direct puncture method was advantageous for patients with carcinomas in the upper digestive tract as only few mechanical alterations take place along tumorous tissues following PEG while contamination with bacteria and neoplastic cells from the tumor region into the abdomen are precluded.

[Basic principles of enteral nutrition, tube techniques, percutaneous endoscopic gastrostomy]. / Grundlagen der enteralen Ernährung, Sondentechniken, PEG.

Cachexia of malignancy is a heterogenous and dynamic phenomenon. Thirty to fifty percent of all oncologic patients suffer from malnutrition. Patients with ENT carcinomas, from the clinical view-point, are clearly high-risk patients. Essentially, malnutrition in ENT carcinoma patients is attributable to reduced or even insufficient energy supply and intake of nutrients as a result of pain experienced in swallowing and constrictions of the upper swallowing tract. Malnutrition has turned out to be a factor entailing an unfavourable prognosis and, frequently, limiting a therapy. In a survey conducted by the Endoscopy Working Group of the German Society for Otorhinolaryngology, Head and Throat Surgery, 70% of the university ENT hospitals confirmed that their patients experienced a clinically relevant weight loss in the range from 3 to 10 kg during oncologic causal treatment. Tube feeding with liquid formula diets is the most efficient, least-risk approach to long term use, and should already be adopted prior to therapy irrespective of scheduled oncologic causal therapy. The feeding tube placed by percutaneous endoscopically controlled gastrostomy is increasingly becoming an alternative to a nasogastric tube. Two basic PEG techniques have been employed: 1. the transoral pull technique and 2. direct puncture. In direct puncture, as distinct from the pull technique, iatrogenic dispersal of tumour cells from the primary location of the tumour with subsequent implantation in the gastric or abdominal wall is definitely ruled out. In the ENT Clinic of Magdeburg University, we decided to adopt direct puncture and, since 1991, this technique has been used in interdisciplinary co-operation with the Magdeburg University Clinic of Gastroenterology and successfully employed in 660 patients with advanced carcinomas of the upper swallowing tract. Severe PEG-induced abdominal complications were extremely rare, observed in as little as 0.5% of the cases. For enteral feeding through PEG which maintained or even improved the nutritional status, good compliance was noted in 83% of the patients. Prior to PEG and oncologic causal therapy, 36% of the patients showed malnutrition (BMI < 20 kg/m2). At the stage of anamnesis half of the patients indicated that, for the past six months prior to diagnosis of the tumour, they had experienced a weight loss of more than 10% of the calculated ideal body weight. Prior to therapy, 97% of the patients complained of dysphagia-induced reduced or impaired food intake. The various PEG tube techniques, along with their pros and cons, as well as nutritional aspects in oncology are presented for the Magdeburg patients and discussed.