Bioactive dahlein peptides from the skin secretions of the Australian aquatic frog Litoria dahlii: sequence determination by electrospray mass spectrometry.

Eleven dahlein peptides are present in the skin secretion of the Australian aquatic frog Litoria dahlii. All peptides have been sequenced using a combination of electrospray mass spectrometry (ES-MS) and Lys-C digestion/MS, with each sequence confirmed by automated Edman sequencing. The 13-residue dahlein 1 peptides (e.g. dahlein 1.1 GLFDIIKNIVSTL-NH(2)) exhibit weak wide-spectrum antimicrobial activity but no significant activity in the anticancer testing program of the National Cancer Institute (Washington). There are no potent antimicrobial peptides present in the glandular secretion, but the dahleins 5 strongly inhibit the formation of NO by neuronal nitric oxide synthase (e.g. dahlein 5.1 GLLGSIGNAIGAFIANKLKP-OH).

The antibiotic and anticancer active aurein peptides from the Australian Bell Frogs Litoria aurea and Litoria raniformis the solution structure of aurein 1.2.

Seventeen aurein peptides are present in the secretion from the granular dorsal glands of the Green and Golden Bell Frog Litoria aurea, and 16 from the corresponding secretion of the related Southern Bell Frog L. raniformis. Ten of these peptides are common to both species. Thirteen of the aurein peptides show wide-spectrum antibiotic and anticancer activity. These peptides are named in three groups (aureins 1-3) according to their sequences. Amongst the more active peptides are aurein 1.2 (GLFDIIKKIAESF-NH2), aurein 2.2 (GLFDIVKKVVGALGSL-NH2) and aurein 3.1 (GLFDIVKKIAGHIAGSI-NH2). Both L. aurea and L. raniformis have endoproteases that deactivate the major membrane-active aurein peptides by removing residues from both the N- and C-termini of the peptides. The most abundant degradation products have two residues missing from the N-terminal end of the peptide. The solution structure of the basic peptide, aurein 1.2, has been determined by NMR spectroscopy to be an amphipathic alpha-helix with well-defined hydrophilic and hydrophobic regions. Certain of the aurein peptides (e.g. aureins 1.2 and 3.1) show anticancer activity in the NCI test regime, with LC50 values in the 10-5-10-4 M range. The aurein 1 peptides have only 13 amino-acid residues: these are the smallest antibiotic and anticancer active peptides yet reported from an anuran. The longer aurein 4 and 5 peptides, e.g. aurein 4.1 (GLIQTIKEKLKELAGGLVTGIQS-OH) and aurein 5. 1 (GLLDIVTGLLGNLIVDVLKPKTPAS-OH) show neither antibacterial nor anticancer activity.

Analysis of radon-associated squamous cell carcinomas of the lung for a p53 gene hotspot mutation.

Squamous cell lung carcinomas (SCC) from former employees of the Wismut uranium mining company (Saxony, Germany) were obtained from the Stollberg Archive in order to screen for p53 tumour suppressor gene codon 249 arg-->met hotspot mutations, a putative molecular bio-dosimeter of alpha-particle (radon) exposure (Taylor et al (1994) Lancet 343: 86-87; McDonald et al (1995) Cancer Epidemiol Biomarkers Prevent 4: 791-793). Of the 29 archived samples of SCC meeting quality criteria for DNA analysis by polymerase chain reaction (PCR) and Haelll restriction enzyme digestion, two tumours were found that harboured this mutation. DNA sequencing confirmed the presence of a G to T base substitution within the Haelll site spanning codons 249 and 250 of the p53 gene that results in replacement of arginine (wild-type) by methionine at residue 249. When these data are combined with those from our previous study of tumours from the Stollberg Archive in which 50 lung tumours were examined, (including nine SCCs), we conclude that the G-->T (arg-->met) codon 249 mutation prevalence in the Wismut miner cohort is not sharply elevated in lung cancers in general (two mutations/79 tumours), or specifically in SCCs of the lung (two mutations/38 SCC) when compared to data from lung cancer patients with no reported occupational exposure to radon gas.

Ras gene mutations in vinyl chloride-induced liver tumours are carcinogen-specific but vary with cell type and species.

Previous studies have shown that a high proportion (5/6) of human liver angiosarcomas (ASL) associated with exposure to vinyl chloride (VC) contains a GC-->AT mutation at the Ki-ras codon 13. This mutation, however, has not been found in 5 ASL or 2 hepatocellular carcinomas (HCC) induced in rats by VC. These 2 HCC did contain a mutation at codon 61 of the Ha-ras gene. In order to extend this study and further explore the mechanisms of tumour induction, an additional 6 ASL and 6 HCC induced in rats by VC were analysed for ras gene point mutations, as well as 10 rat and 10 murine ASL induced by vinyl fluoride (VF), and 5 ASL, 6 Kupffer cell sarcomas, 4 HCC and 2 cholangiocellular carcinomas induced by Thorotrast in rats. Tumour DNA was analysed by PCR-SSCP and direct sequencing. None of the rodent ASL contained a mutation at codon 13 of the Ki-ras gene showing that the ras gene mutational pattern is species-specific. The CAA-->CTA mutation, previously found at codon 61 of the Ha-ras gene in rat HCC, was observed in 5 further VC-induced HCC but was not detected in the Thorotrast-induced HCC, suggesting carcinogen-specificity. This mutation was also absent in VC-induced ASL, which supports the cell-specificity of the ras mutational pattern in chemically induced tumours. No predominant mutation was detected in VF- and Thorotrast-induced tumours. Thus, a given mutation in a tumour may be carcinogen-specific but also depend on the species and the cell type.

German uranium miner study--historical background and available histopathological material.

Mining activities in the former German Democratic Republic were documented as early as 1168 in the ore mountains (Erzgebirge) of Saxony. Silver, bismuth, cobalt, nickel and tungsten were mined from then up to the end of the 19th century. After the Second World War, the Soviet Occupation Authorities reopened the old silver mines in Saxony to mine uranium for the Soviet nuclear industry. About 400, 000 workers produced a total of 220,000 tons of uranium during the years 1946 to 1990. After the reunification of Germany, the archive of the Institute of Pathology of the mining area was opened for research. It contains protocols of 28,975 autopsy cases and about 400,000 slides collected from 1957 to 1992, about 66,000 tissue blocks, and 238 whole lungs. From the autopsy cases, 17,466 could be identified as workers of the uranium mining company. The remainder of the cases were in the population of the mining area. A comparison of the frequencies of malignancies of male workers older than 15 years with those of the population of the mining area for the years 1957 to 1989 demonstrates a significantly higher percentage of lung cancer among the uranium miners. There was no significant difference for other solid cancers and leukemias.

German uranium miner study--pathological and molecular genetic findings. German Uranium Miner Study, Research Group Pathology.

Uranium miners of the former Wismut company in Germany form the largest cohort of workers exposed to (222)Rn and dust in the world. The German Uranium Miner Study, Research Group Pathology, is evaluating the central pathology archive of the Wismut company. The main tasks of our study are pathological-anatomical and molecular genetic investigations of 28,975 autopsy cases and the evaluation of mining pollutants in the lungs by neutron activation analysis. As part of an observer agreement study, lung tumors are classified according to the WHO/IASLC classification and nontumorigenic lung disorders are registered. Lung tumors were analyzed for the presence of a proposed radon-specific mutation in the TP53 gene (formerly known as p53). Interim results are: (a) In the years 1957 to 1965, a high rate (69%) of small cell carcinomas was found which had declined to 34% by 1990. (b) The percentage of the deceased who suffered from silicosis is not higher in the group of lung tumors than in other tumor groups or the nontumor group. (c) The hypothesis of a radon-characteristic hotspot mutation in the TP53 tumor suppressor gene is not supported by our investigations. (d) Neutron activation analysis demonstrates that uranium, arsenic, chromium, cobalt and antimony can be found in tissue samples from the miners even when they had stopped working more than 20 years before death.

The german thorotrast study: recent results and assessment of risks.

The German Thorotrast study comprises 2,326 patients and 1,890 controls. Forty-eight Thorotrast patients and 239 controls are still alive and are invited for a follow-up examination every 2 years. In the deceased patients, the following neoplastic diseases with excess rates were registered (Thorotrast/controls): liver cancer (454/3); cancer of the bile ducts, including gallbladder (42/7); myeloid leukemia (40/7); myelodysplastic syndrome (30/4); plasmacytoma (10/2); non-Hodgkin's lymphoma (15/5); bone sarcoma (4/1); malignant peritoneal or pleural mesothelioma (9/0). Dose calculations are based on results of whole-body counting, X-ray films, and data obtained from the hospital records on the volume of Thorotrast injected. For liver cancer, the cumulative risk estimate was calculated to be 40 per 10(4) person Sv (radiation weighting factor = 20). These figures are close to the results of the Danish study and are comparable to the results of the Life Span Study of A-bomb survivors after 40 years at risk with 18 to 48 liver cancers per 10(4) person Sv. For hematopoietic malignancies, the cumulative risk was calculated to be about 7 per 10(4) person Sv (radiation weighting factor = 20). This risk estimate is lower by a factor of 10 compared to the results of the Life Span Study.

Host defence peptides from the skin glands of the Australian blue mountains tree-frog Litoria citropa. Solution structure of the antibacterial peptide citropin 1.1.

Nineteen citropin peptides are present in the secretion from the granular dorsal glands of the Blue Mountains tree-frog Litoria citropa; 15 of these peptides are also present in the secretion from the submental gland. Two major peptides, citropin 1.1 (GLFDVIKKVASVIGGL-NH2), citropin 1.2 (GLFDIIKKVASVVGGL-NH2) and a minor peptide, citropin 1.3 (GLFDIIKKVASVIGGL-NH2) are wide-spectrum antibacterial peptides. The amphibian has an endoprotease which deactivates these membrane-active peptides by removing residues from the N-terminal end: loss of three residues gives the most abundant degradation products. The solution structure of the basic peptide citropin 1.1 has been determined by NMR spectroscopy [in a solvent mixture of trifluoroethanol/water (1 : 1)] to be an amphipathic alpha-helix with well-defined hydrophobic and hydrophilic regions. The additional four peptides produced by the dorsal glands are structurally related to the antibacterial citropin 1 peptides but contain three more residues at their C-terminus [e.g. citropin 1.1.3 (GLFDVIKKVASVIGLASP-OH)]. These peptides show minimal antibacterial activity; their role in the amphibian skin is not known.

p53 gene mutation analysis in tumors of patients exposed to alpha-particles.

The p53 gene was examined for point mutations in archived, alpha-radiation-associated lung and liver cancers. Lung tumors of 50 uranium miners in Germany were screened by restriction fragment length analysis for the putative hotspot mutation at codon 249 (Arg-->Met) previously detected in a significant fraction of miners from the Colorado Plateau, USA. This mutation has been proposed as a marker of radon exposure. None of the tumors we examined harbored the hotspot mutation. Five of the 50 tumors, however, did indeed harbor exon 7 mutations, as determined by subsequent mutation analysis of exon 7. These mutations were dispersed among various codons and may be attributable to heavy tobacco smoking in this cohort. In support of this interpretation, we found no mutations in exons 5-8 of the p53 gene in 13 iatrogenic liver cancers induced by injection of Thorotrast, an alpha-emitting radiocontrast agent. We propose that if the p53 tumor suppressor gene is a target for the carcinogenic action of alpha-particle radiation, loss of suppressor function may occur preferentially by mechanisms such as intrachromosomal deletions, rather than by base substitution mutations.

Preneoplastic foci of altered hepatocytes induced in rats by irradiation with alpha-particles of Thorotrast and neutrons.

Prestages of hepatocellular neoplasms induced in rats by continuous internal alpha-radiation of Thorotrast or by fractionated external radiation with neutrons were studied by cytomorphological, cytochemical and morphometric methods. Irradiation with both Thorotrast and neutrons resulted in a significant increase in the number and volume fraction of foci of altered hepatocytes (FAH), the occurrence of which at 14 months correlated well with the previously reported increased incidence of hepatocellular neoplasms appearing after long lag periods. The morphological and biochemical phenotypes of radiation-induced FAH were similar to those of preneoplastic lesions described earlier in hepatocarcinogenesis elicited by chemicals or viruses.

[Mucinous cystadenomas and cystadenocarcinomas of the pancreas--the pancreaticoscopy as a new device for endoscopic and histological diagnosis]. / Muzinöse Zystadenome und Zystadenokarzinome des Pankreas--die Pankreatikoskopie als neues Instrument der endoskopischen und feingeweblichen Diagnosesicherung.

Recent advances in diagnostic imaging procedures offer the opportunity for detection of rare cystic neoplasms of the pancreas. Cystadenomas of the pancreas have been reported to represent 10% of cystic pancreatic lesions. Serous microcystic cystadenoma, megacystic mucinous and duct-ectatic mucinous cystadenoma were distinguished. While the serous cystadenoma is benign, in general the megacystic and the duct-ectatic mucinous cystadenoma have a significant malignant potential. With pancreatoscopy, a rather new endoscopic technique, five cases of mucinous megacystic cystadenoma were diagnosed preoperatively by macroscopic and microscopic means. In one case, development of malignant neoplasm was diagnosed, one patient did not undergo surgery because of her age. Three patients were operated (total pancreatectomy in one case, duodeno-hemipancreatectomy in two cases) and are without any further signs of recurrence and free of symptoms in a one year to four year clinical follow-up.

[Barrett esophagus with severe epithelial dysplasia--always surgery? A case report]. / Barrett-Osophagus mit schwerer Epitheldysplasie--immer Operation?--Eine Kasuistik.

A 57 year-old patient presented with a Barrett's epithelium over the length of 18 cm. We found the typical functional changes of acid reflux and hypomotility in the distal esophagus. There was a history of chemotherapy for seminoma 30 years ago. Because of the repeated finding of severe dysplasia surgery was proposed. The patient died in the postoperative period with the signs and symptoms of pulmonary embolism. There was no invasive tumor found in the resected part of the esophagus. Main aspects of the etiology and histological characterism of Barrett's esophagus and the indication for surgery in cases with severe dysplasia are discussed.

The effects of Thorotrast and quartz on the induction of lung tumors in rats.

In a long-term animal study, the combined and separate effects of Thorotrast (colloidal 232ThO2) and silica dust on the induction of lung tumors were investigated. Female Wistar rats were exposed for 29 d to aerosol concentrations of quartz of either 6 mg m-3, 30 mg m-3, or 0 mg m-3 (6 h d-1, 5 d wk-1). After inhalation, one-half of all exposed animals received a single intravenous injection of enriched Thorotrast (600 microL, 2960 Bq 228 Th mL-1). In all quartz-exposed groups the incidence of benign and malignant lung tumors turned out to be more than 40%. The additional Thorotrast treatment (lifelong exhalation of 220Rn) led to a marked shortening of latency times (first lung tumor was found 1 y after treatment) and to a higher total incidence in the animals exposed to 30 mg m-3 quartz (57 of 87 animals with lung tumors = 65.5%). In the group treated only with Thorotrast, three of 87 animals developed lung tumors. Statistical methods that correct for intercurrent mortality showed a significant increase of the lung tumor risk with respect to Thorotrast treatment, even for the low quartz groups with nearly similar incidences of lung tumors (in the group with ThO2, 39 out of 87 = 44.8%; in the group without ThO2, 37 out of 82 = 45.1%). The tumors were found predominantly in the peripheral regions of the lung and were preceded by proliferation and hyperplasia of the alveolar and bronchiolar epithelium. The results demonstrate a pronounced interactive effect of quartz and Thorotrast on carcinogenesis of the lung. The underlying possible mechanisms are discussed.

The combined and separate action of neutron radiation and zirconium dioxide on the liver of rats.

To simulate the chronic alpha radiation of Thorotrast, the liver of female Wistar rats was exposed to fractionated neutron irradiation at 14-d intervals (0.2 Gy per fraction) over 2 y to a total dose of 10.0 Gy. Prior to the start of irradiation, one-half of the animals received 120 microL of non-radioactive Zirconotrast (ZrO2), which is comparable to Thorotrast with regard to all other physical and chemical properties. One year after beginning irradiation, the first liver tumor was detected. At the end of the life-span study, the incidence of irradiated animals with liver tumors was about 40%. In the animals treated additionally with ZrO2, the incidence, time of onset, and overall number of liver tumors was nearly equal, indicating that the fractionated neutron irradiation was the exclusive cause of tumor development. The lifelong-deposited ZrO2 colloid had no stimulating effect. Compared to earlier animal studies dealing with Thorotrast, the same histological types of benign and malignant liver tumors were found.

[Ménétrier's disease--a rare cause of a protein deficiency syndrome]. / Morbus Ménétrier--seltene Ursache eines Eiweissmangelsyndroms.

Hypoproteinaemia (total proteins 5.2 g/dl) and hypoalbuminaemia (2.7 g/dl) were demonstrated in a 44-year-old woman with leg oedema during the previous four months and 10-kg weight gain during the previous year. A protein-losing enteropathy was diagnosed, all other causes having been excluded. Gastroscopy revealed giant hypertrophic gastritis. A biopsy showed foveolar hyperplasia with some inflammatory infiltrates, typical of Ménétrier's disease. Endosonography excluded any additional infiltrative process of the bowel wall. Long-term treatment with ranitidine, 150 g twice daily, achieved normalization of total protein and albumin concentrations. But the macroscopic changes in the gastric wall were still recognizable on repeat gastroscopy. As there is a danger of malignant degeneration gastroscopy and, if indicated, endosonography should be repeated annually.

[The significance of papillary biopsy in obstruction of Vater's papilla]. / Die Bedeutung der Papillenbiopsie bei Abflussstörungen aus der Papilla Vateri.

Biopsies of the papilla of Vater were taken in 53 patients after a papillotomy had been carried out during a previous ERC. The macroscopic finding of a papillary stenosis of unknown dignity required an exact histological diagnosis. In 35 patients (66%) a duodenitis/papillitis was found on the histological specimens, in 6 patients (11%) a villous adenoma, and in 7 patients an adenocarcinoma (13%). A metastasis of a melanoma, a schwannoma, and a coagulum were diagnosed once. The papillotomy preceding the biopsy was the only necessary therapy in 46 patients, and endoprosthesis was inserted in 5 patients. In 2 patients the tumor was excised by snare, in 4 patients a surgical resection was carried out. The incidence of malignancy in papillary stenosis emphasizes the significance of a biopsy for histological confirmation of the diagnosis if endoscopically a papillary stenosis is detected.

[Polyposis of the stomach caused by multiple xanthomas]. / Polypose des Magens durch multiple Xanthome.

Case report on a rare gastric polyposis. Endoscopically the lesions appear as multiple, yellowish, partly villous polypoid changes histologically representing as foam cells und showing deposits of lipids on characteristic stains. Etiopathogenesis are these lesions and their differential diagnosis are discussed.

[Malignant melanoma of the nailbed under a skin graft]. / Malignes Melanom des Nagelbetts unter einem Hauttransplantat.

The authors report on a case of subungual malignant melanoma, which developed beneath a split-skin graft. The patient had an accident which caused a pathologic growth of the nail. Eleven years later the patient removed the nail, because it became moist, and a surgeon grafted the nail-bed with a split-thickness skin. Six years later we saw a 2 X 2 cm tumor under the skin graft and histologic examination showed a nodular malignant melanoma. Diagnostic and therapeutic guidelines for subungual and acral melanomas are discussed.