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Biomedical subjects

M Ammann

Publications and source records attributed to M Ammann.

At least 19 recordsLinked to original sources
PubMed2005

Finnish workshop on the restoration of contaminated residential areas after a nuclear accident: strategy generation and impact assessment.

Scenario-focused workshops on the restoration of contaminated residential areas are planned in a number of European countries within the EVATECH project of the EU's Fifth Framework Programme. The intention is to identify factors driving decision-making, explore the kinds of strategies that might be appropriate, develop methods for stakeholder involvement, and reveal information needs. The scenario of the Finnish workshop is presented. A policy generation scheme is proposed that yields a manageable but feature-rich set of strategies that is not constraint by lack of feasibility, justification, or public acceptability. The scheme rests on the premise that the affected area is divided into zones according to the level of contamination and that clean-up actions are applied in any combination and in combination with relocation.

Cesium Radioisotopes↗
PubMed2005

Photoenhanced uptake of gaseous NO2 on solid organic compounds: a photochemical source of HONO?

In several recent field campaigns the existence of a strong daytime source of nitrous acid was demonstrated. The mechanism of this source remains unclear. Accordingly, in the present laboratory study, the effect of light (in the range 300-500 nm) on the uptake kinetics of NO2 on various surfaces taken as proxies for organic surfaces encountered in the troposphere (as organic aerosol but also ground surfaces) was investigated. In this collaborative study, the uptake kinetics and product formation rate were measured by different flow tube reactors in combination with a sensitive HONO instrument. Uptake on light absorbing aromatic compounds was significantly enhanced when irradiated with light of 300-420 nm, and HONO was formed with high yield when the gas was humidified. Especially organic substrates containing a combination of electron donors, such as phenols, and of compounds yielding excited triplet states, such as aromatic ketones, showed a high reactivity towards NO2. Based on the results reported a mechanism is suggested, in which photosensitised electron transfer is occurring. The results show that HONO can be efficiently formed during the day in the atmosphere at much longer wavelengths compared to the recently proposed nitrate photolysis.

Aerosols↗
PubMed2001

Heterogeneous reaction of NO2 on diesel soot particles.

Soot particles were collected from a diesel engine using a procedure that realistically mimics exhaust gas conditions in tailpipes and during dilution at room temperature. After being sampled, the particles were exposed to NO2 concentrations and relative humidity in ranges relevant for the troposphere using 13N as tracer. Gas-phase nitrous acid(HONO) and irreversibly bound (i.e., chemisorbed) species were the main reaction products with initial yields of 80-90% and about 10%, respectively. Neither NO nor HNO3 were detectable. The HONO formation increased with increasing engine load (i.e., with a decreasing air to fuel ratio, lambda). The reaction rates of HONO and chemisorbed NO2 increased with increasing NO2 concentration and did not depend on relative humidity. At the beginning of reaction, the uptake coefficient averaged over 3 min ranged from 5 x 10(-6) to 10(-5) for NO2 concentrations between 2 and 40 ppb. The HONO formation rates decreased with time, indicating consumption of reactive surface species, while the chemisorption rates remained almost constant. The total HONO formation potential of the particles was estimated to about 1.3 x 10(17) molecules/mg of diesel soot or to about 4.7 mg/kg of diesel fuel, indicating that the reaction between NO2 and diesel soot particles does not provide a significant secondary HONO source in the atmosphere. A Langmuir-Hinshelwood type reaction mechanism was proposed that adequately describes the observed results and also allows discussing important general features of reactions on soot.

Environmental Monitoring↗
PubMed2000

[Advanced breast biopsy instrumentation (ABBI). Histopathologic evaluation of a new investigation method].

The ABBI (advanced breast biopsy instrumentation) system has only recently been available for diagnostic excisional biopsy of small, non-palpable lesions of the breast. Between 1.1.1998 and 31.3.1999 this method was utilized in 40 patients with suspicious microcalcifications (n = 25), newly developed densities (n = 11) and a combination of microcalcifications and densities (n = 4). In 12 cases malignancy was diagnosed, in 11 cases a subsequent resection was performed. In every case sufficient tissue for diagnosis was obtained, in not a single case the diagnosis had to be revised in case of subsequent resection. Orientation within the specimen is accurate, the resection margins can be judged unequivocally. Any necessary special examinations can be performed on the resected tissue. In our experience, ABBI is a valuable and elegant tool for diagnosing small suspicious lesions of the breast.

Biopsy↗
PubMed1995

[Diagnosis of malignant uterine tumors by transvaginal ultrasound].

Two hundred and three non-pregnant women who underwent diagnostic dilatation and curettage or hysterectomy were included in a prospective study designed to assess the accuracy of transvaginal sonography in conforming or excluding the presence of uterine cancer. All preoperative sonographic findings were compared with the final histological diagnosis. The predictive value of sonographic evidence of malignancy was 71.1% (32/45), the predictive value of benign disease was 95.6% (151/158). Sensitivity was 82.1% (32/39) and specificity 92.1% (151/164). Although sensitivity and specificity increased as compared to an earlier study using transabdominal ultrasound, we recommend dilatation and curettage in women with postmenopausal bleeding.

Adult↗
PubMed1994

[Clinical experiences with PACS: digital radiology].

We present our experience during the first 21 months of using hospital-wide network technology and digital archiving in connection with digital radiology in the Radiology Department at the SMZO/Danube hospital in Vienna. This means digital generation, archiving and distribution of radiographs as well as monitor reporting embedded in HIS and RIS. The clinical use of PACS demands full integration of all subsystems and modalities in a digital way, as was first realized at the Danube Hospital. With this approach, a reduction in radiation dose, improved communication and thus a reduction in the length of hospital stay and health care cost are attained.

Austria↗
PubMed1993

Determination of ionic species formed during growth of Escherichia coli by capillary isotachophoresis.

The ionic species that are formed during the microbial growth of Escherichia coli were determined by capillary isotachophoresis as a function of the time of cultivation. This formation was indicated by the change in a sum parameter, the impedance of the nutrient broth, measured by a special electrode system. Based on the determination of the individual ions formed under the given conditions (identified as acetate, lactate, alpha-ketoglutarate, fumarate, ammonium and probably a simple amine), the change in conductivity was calculated and compared with that obtained by the impedance measurement of the bulk medium. From the results it can be concluded that the change in the sum parameter as a function of time is originated by the ions determined.

Electric Impedance↗
PubMed1993

[Ultrasound diagnosis of cervical lymph node tuberculosis].

Lymph node tuberculosis is the most frequent tuberculous manifestation in the otorhinolaryngological area. In 13 patients with histologically verified tuberculous lymphadenitis cervical sonographic examinations revealed characteristic findings. The sonographic features typical for this disease were multiple, enlarged, conglomerating roundish and oval lymph nodes. These lymph nodes were hypoechoic, exhibited dorsal sound amplification and had sharp margins. With caseation, however, there were blurred borders. In cold abscesses an inhomogeneous texture with inhomogeneous shadows was found. Differential diagnosis included non-specific abscess-forming lymphadenitis, lymph node metastases and malignant lymphoma. A tentative diagnosis of cervical lymph node tuberculosis may be made due to the polymorphous sonographic pattern if history and clinical findings are taken into account. A proper histological and microbiological work-up is still essential for confirmation of the sonographic diagnosis.

Adult↗
PubMed1993

[The sonographic diagnosis of recurrences after parathyroid autotransplantation. The preliminary results of a prospective study].

Reactive renal hyperparathyroidism is a complication of chronic renal failure. The treatment of choice is resection of all four parathyroid glands and autotransplantation of a piece of parathyroid into the muscles of the fore-arm. In a prospective study, the transplant site was examined postoperatively in 35 patients by sonography on at least one occasion. In 3 patients (8.6%) enlargement of the autotransplant was observed and in 2 patients this was associated with clinical and biochemical changes; these were also confirmed histologically. The sonographic appearances of satisfactory and abnormal transplants are described. The value of the method remains to be determined.

Adult↗
PubMed1992

[Is the cryopreservation of sperm of young tumor patients reasonable?].

Operation, retroperitoneal lymphadenectomy, irradiation and chemotherapy may reduce the fertility potential of young male patients suffering from a malignant tumour. Prediction of the reversibility is difficult. Cryopreservation is a possibility to maintain the fertility of such patients. Unfortunately, the quality of the sperm is often reduced beforehand. The sperm motility is noticeably reduced by the freezing process. But the sperm preservation may help to reduce the psychological stress of the patients, thus improving their quality of life. Therefore, we recommend the use of the method liberally, although only few patients will make use of their sperm later. There has been no known teratogenicity to date. We report on our own experience with cryopreservation in 39 patients.

Adult↗
PubMed1992

[Induction of labor with a new intracervically administered prostaglandin E2 gel. Report of initial experience].

We report on our experience with the induction of labour using 0.5 mg of prostaglandin E2 gel (Cerviprost, Organon) intracervically. Out of 43 cases, 27 were primiparae. Indication for induction was: 10 post-term pregnancies, 9 PROM's > 24h, 12 foetal and 11 maternal indications. Mean Bishop score before induction was 3.1 and 9 hours later or at the beginning of regular contractions 6.7. In 9 of the 43 cases induction was unsuccessful. There were 23 spontaneous vaginal deliveries, 6 forceps and 5 Caesarean sections. Uterine hyperstimulation was found in 6 cases, 5 of which occurred during the first 16 inductions, and only one was seen during the following 27. A possible reason may be unrecognised extra-amniotic application of the gel. Intracervical prostaglandin seems to be an appropriate method not only for cervical ripening but also for induction of labour in cases with a low Bishop score. Although side effects are rare, sufficient monitoring and control of mother and foetus are mandatory.

Administration, Intravaginal↗
PubMed1992

[Quality control of laser imagers].

Multiformat imagers based on laser systems are used for documentation in an increasing number of investigations. The specific problems of quality control are explained and the persistence of film processing in these imager systems of different configuration with (Machine 1: 3M-Laser-Imager-Plus M952 with connected 3M Film-Processor, 3M-Film IRB, X-Rax Chemical Mixer 3M-XPM, 3M-Developer and Fixer) or without (Machine 2: 3M-Laser-Imager-Plus M952 with separate DuPont-Cronex Film-processor, Kodak IR-Film, Kodak Automixer, Kodak-Developer and Fixer) connected film processing unit are investigated. In our checking based on DIN 6868 and ONORM S 5240 we found persistence of film processing in the equipment with directly adapted film processing unit according to DIN and ONORM. The checking of film persistence as demanded by DIN 6868 in these equipment could therefore be performed in longer periods. Systems with conventional darkroom processing comparatively show plain increased fluctuation, and hence the demanded daily control is essential to guarantee appropriate reaction and constant quality of documentation.

Diagnostic Imaging↗
PubMed1991

Urethral isolation of Chlamydia trachomatis in women with urinary incontinence.

The overall prevalence of Chlamydia trachomatis (CT) infection in 168 patients with urinary incontinence was 7.7%. However, in patients with urethral instability CT was found significantly more often than in those with stable urethra (P less than 0.001). Clinical and urodynamic improvement followed the treatment with doxycycline in 8 out of 9 patients with urethral instability. According to our results urethral infection with CT may play an important role in the etiology of urge incontinence and urethral instability.

Adult↗
PubMed1991

Purification and partial characterization of a novel lectin from elder (Sambucus nigra L.) fruit.

A previously unknown haemagglutinin, named Sambucus nigra agglutinin-III (SNA-III), has been purified from the fruit of the elder (Sambucus nigra). Whereas elder bark agglutinin I (SNA-I) is highly specific for terminal alpha 2,6-linked sialic acid residues, SNA-III displays a high affinity for oligosaccharides containing exposed N-acetylgalactosamine and galactose residues. Different N-terminal sequences and the amino acid composition distinguish the fruit lectin from elder bark agglutinin II (SNA-II), which shows a similar carbohydrate specificity. The 40-fold higher affinity of SNA-III for asialofetuin than for human asialo-alpha 1-acid glycoprotein and human asialotransferrin respectively suggests a preference for O-linked glycans. SNA-III occurs mainly as a monomeric glycoprotein, but tends to form di- and oligo-meric aggregates. This aggregation seems to mediate the multivalent interaction, leading to agglutination. SDS/PAGE revealed two major polypeptides with apparent molecular masses of 32 and 33 kDa respectively. This heterogeneity is probably a result of proteolysis in the C-terminal region. Binding to concanavalin A and susceptibility to peptide: N-glycosidase F indicated the presence of N-glycosidically linked oligosaccharides.

Amino Acid Sequence↗
PubMed1991

[Differential diagnosis of cystic ovarian tumors by determination of estradiol in cystic aspirate].

Since ultrasound is routinely used in gynecologic practice, cystic ovarian tumours are detected and, as a result, more unnecessary operations are performed. The aim of our study was, to determine the value of measurement of intracystic oestradiol (E2) in the differential diagnosis of simple cystic ovarian tumours. 30 patients, who underwent a laparotomy for cystic ovarian tumour, had prior measurements of E2 content of the cystic fluid. In 7 functional cysts, E2 was higher than 3,700 pmol/l and in the 23 neoplastic cysts, E2 level was lower than 1,200 pmol/l. Our results and the review of the literature suggest, that E2 content of the intracystic fluid may help to differ between functional and neoplastic cystic ovarian tumours.

Adult↗
PubMed1991

[Sudeck's syndrome of the hip in pregnancy. A case report and review of the literature].

A case algodystrophy of the hip during pregnancy is reported and the literature is reviewed. Mostly symptoms manifest in the last trimenon and sometimes in the postpartum period. Typically only the left hip is involved. The symptomatology shows usually three periods: During a first phase there is a sudden onset of symptoms, while in the second phase symptoms remain stable and after birth the pain disappears in a short time. For diagnosis the clinical signs, radiology, radionuclide scans and MRI are helpful. Therapeutically physiokinesitheraphy and analgesics are recommended.

Diagnosis, Differential↗