Coherent bremsstrahlung in the alpha + p system at 50 MeV/nucleon

Photons originating from coherent bremsstrahlung have been measured over a large dynamic range for the reaction of 200 MeV alpha particles with protons. At low photon energies the bremsstrahlung spectrum exhibits the classical behavior with an approximate 1/E(gamma) shape. At higher photon energies there is a pronounced contribution from capture into the unbound ground state and first excited state of 5Li. These results allow one, for the first time, to test theoretical models for a consistent description of bremsstrahlung and radiative capture in a complex system. Calculations predict both features qualitatively but fail to account for their relative importance.

[Dialysis-associated amyloid osteopathy--the radiological aspects]. / Dialyseassoziierte Amyloidosteopathie--radiologische Aspekte.

Amongst the complications of dialysis, amyloid osteopathy is getting increasingly significant. It is due to deposition of beta 2-microglobulin. To determine the incidence and time of development of this complication, the skeletal radiographs of 185 patients undergoing dialysis, some for up to ten years, were analysed retrospectively. In about 10% of patients, the presence of beta 2-microglobulin osteopathy may be expected. The radiological features, sites of predilection and differential diagnosis of amyloid osteopathy and of other skeletal changes due to dialysis are discussed.

[Intestinal contrasting in abdominal computed tomography]. / Zur Frage der Darmkontrastierung in der abdominellen Computertomographie.

In 56 patients undergoing abdominal CT the gastrointestinal tract was defined by negative contrast instead of the conventional positive contrast from an iodine containing contrast medium. The contrast material was a 2 1/2% mannitol solution and was used for filling the rectum. Filling of the gastrointestinal tract was of similar quality to that obtained with positive contrast media. The number of artifacts due to high contrast boundaries was slightly greater with the negative contrast than it would have been with positive contrast. Differentiation of the gastrointestinal tract from other abdominal organs was equally good for both methods. The negative contrast method was poor in diagnosing cystic tumours but proved much better than positive contrast for evaluating the wall of the gastrointestinal tract.

[Diagnosis of pleural effusions and atelectases: sonography and radiology compared]. / Diagnostik von Pleuraergüssen und Atelektasen: Sonographie und Radiologie im Vergleich.

In a prospective study it was shown that chest ultrasonography is superior to conventional x-ray diagnosis of recumbent patients in diagnosing pleural effusion and lung atelectasis. In 110 supine radiographs we found a sensitivity of 47% and a specificity of 71% for right pleural effusions and a sensitivity of 55% and a specificity of 93% for left pleural effusions in comparison to 110 sonographic examinations. The results of supine radiographs in detection of atelectasis were less efficient: sensitivity for the right side: 7%; sensitivity for the left side: 13.5%. Hence, the knowledge of chest ultrasonographic diagnosis can improve the interpretation of supine radiographs.

Neutral-pion photoproduction off protons in the energy range 0.3 GeV

Single pi(0) photoproduction has been studied with the CB-ELSA experiment at Bonn using tagged photon energies between 0.3 and 3.0 GeV. The experimental setup covers a very large solid angle of approximately 98% of 4pi. Differential cross sections dsigma/dOmega have been measured. Complicated structures in the angular distributions indicate a variety of different resonances being produced in the s channel intermediate state gammap-->N(*)(Delta(*))-->ppi(0). A combined analysis including the data presented in this letter along with other data sets reveals contributions from known resonances and evidence for a new resonance N(2070)D15.

Photoproduction of eta mesons off protons for 0.75 GeV

Total and differential cross sections for the reaction p(gamma,eta)p have been measured for photon energies in the range from 750 MeV to 3 GeV. The low-energy data are dominated by the S11 wave which has two poles in the energy region below 2 GeV. Eleven nucleon resonances are observed in their decay into peta. At medium energies we find evidence for a new resonance N(2070)D15 with (M,Gamma)=(2068+/-22, 295+/-40) MeV. At gamma energies above 1.5 GeV, a strong peak in the forward direction develops, signaling the exchange of vector mesons in the t channel.

[The variable course of pulmonary histiocytosis X]. / Variabler Verlauf der pulmonalen Histiozytosis X.

The authors report on the course seen in 7 cases of pulmonary histiocytosis X. In Group I (3 patients) immunosuppressive therapy was initiated on account of severe general symptoms and reduced pulmonary function. Remission was induced in 2 cases, whereas relapses occurred intermittently in one patient. In Group II without general symptoms and largely normal pulmonary function the course was only monitored. Progression did not occur with any of the patients. Pulmonary histiocytosis X should be treated with corticosteroid monotherapy in case of progressive deterioration of pulmonary function and/or if there are severe general symptoms. Chance findings in patients who are otherwise free from complaints should merely result in a closely meshed control checkup before taking any action.

[Pulmonary infiltrations with eosinophilia (pulmonary eosinophilia)]. / Pulmonale Infiltratbildungen mit Eosinophilie ("pulmonale Eosinophilie").

The pulmonary eosinophilias are characterised by radiographic lung shadows with either a peripheral blood eosinophilia of more than 450/microliter or histologic abnormalities consisting of both interstitial and intraalveolar accumulations of eosinophils and macrophages. We describe the clinical features, radiographic changes, results of bronchoscopy and follow-up studies of three women with chronic eosinophilic pneumonia of unknown aetiology. In all patients the illness resolved rapidly after treatment with corticosteroids, however one patient experienced a second episode after treatment withdrawal. We demonstrate the wide differential diagnosis of the syndrome of pulmonary eosinophilia.

[Lung function in chronic persistent pulmonary embolism]. / Lungenfunktion bei chronisch persistierender Lungenembolie.

Chronic thromboembolic pulmonary hypertension is characterized by widespread obstruction of the pulmonary arteries with organized thrombus. Typically, the afflicted patients present with complaints of progressive dyspnea and exercise intolerance. The typical functional picture of the 22 patients in this series revealed normal lung volumes. Only about 10% of the subjects had mild restrictive defects. The universal findings were mild to moderate hypoxemia, chronic respiratory alkalosis, high pulmonary vascular resistance and low cardiac output. Pathophysiological mechanisms responsible for dyspnea in chronic thromboembolic pulmonary hypertension are discussed.

[Rheumatologic and radiologic symptoms of dialysis-associated beta 2-microglobulin amyloidosis: long-term retrospective study of 175 chronic hemodialysis patients]. / Rheumatologische und radiologische Symptome der Dialyse-assoziierten beta 2-Mikroglobulin-Amyloidose: Retrospektive Langzeitstudie an 175 chronischen Hämodialysepatienten.

beta 2-microglobulin amyloidosis is a major complication in chronic hemodialysis patients. Destructive arthropathy, spondylarthropathy, and carpal tunnel syndrome are clinical manifestations of beta 2M amyloid depositions within the joints, intervertebral discs, and tendon sheets. We have investigated the prevalence of beta 2M amyloidosis associated radiological joint lesions in a population of 175 patients on chronic hemodialysis. In 32 of 175 patients the diagnosis of amyloidosis arthropathy and spondylarthropathy was made by radiomorphological criteria. These 32 patients were asked about rheumatic symptoms (localisation and character of pain, synovitis, carpal tunnel syndrome, influence of dialysis membrane on pain) and examined clinically. Bilateral pain of the shoulders or wrists was complained by most of the patients. 24 of the 32 patients had signs of secondary hyperparathyroidism besides beta 2M-amyloidosis. 29 patients had a carpal tunnel syndrome, 23 of whom had to be operated. beta 2M-amyloid was histochemically demonstrated in all of these 23 cases. Renal transplantation led to immediate pain relief in 3 out of 3 patients, a change of the dialysis membrane (high-flux membrane) improved chronic pain in the majority of patients.

[Rheumatologic and radiologic symptoms of secondary hyperparathyroidism: retrospective long-term study of 175 chronic hemodialysis patients]. / Rheumatologische und radiologische Symptome des sekundären Hyperparathyreoidismus: Retrospektive Langzeitstudie an 175 chronischen Hämodialysepatienten.

Despite recent improvements of hemodialysis (HD) techniques, symptoms due to secondary hyperparathyroidism (HPT) contribute to longtime complications of HD patients. The aim of the present retrospective study was to determine the incidence and localization of radiological joint and bone lesions in 175 patients on chronic HD. In 108 patients the diagnosis of HPT was made by radiologic criteria. 56% had radiomorphologic lesions of the hands, 45% of the acromio-clavicular (AC) joint, 31% of the shoulder, and 27% of the pelvis. No sex difference was found for prevalence of HPT in these patients, nor was one found for any of the underlying renal diseases. There was a negative correlation between elevated serum parathyroid hormone and serum aluminum concentrations. In 111 patients the history of bone and joint pain was evaluated. 54% of these patients suffered from bone pain, arthralgia, and morning stiffness. Radiological lesions of AC-joint correlated with shoulder pain in 38%. Our data show that even in the predialytic phase of renal insufficiency x-rays of the shoulder are helpful in early diagnosis of HPT. Skeletal manifestations specific for one of the underlying renal diseases do not exist. Elevated PTH levels are a good indicator of HPT in these patients, whereas low levels of PTH do not exclude radiological manifestations. In contrast to beta 2-microglobulin amyloidosis, pain does not occur during rest and is not worsened during HD. Treatment with non-steroidal antiinflammatory drugs led to pain relief in the majority of patients. Pain history in patients on chronic HD provides important information concerning the differential diagnosis of HPT/beta 2-microglobulin amyloidosis.

Exclusive measurement of coherent proton-deuteron bremsstrahlung.

For the first time a high-precision proton-deuteron bremsstrahlung experiment has been performed in which all the different exit channels have been distinguished separately. High-precision cross sections and analyzing powers in one of the outgoing channels, namely, the coherent bremsstrahlung with a proton and a deuteron in the final state, are presented at 190 MeV incoming proton beam energy and are compared to calculations based on the low-energy theorem. The results of the calculations vary considerably calling for a fully microscopic calculation. However, using a recipe including the initial- and final-state interactions, the predictions come close to the data.

Exclusive measurement of quasifree proton-neutron bremsstrahlung.

Data on proton-neutron bremsstrahlung have been obtained from a measurement of the quasifree breakup channel in proton-deuteron bremsstrahlung. This high-precision measurement, with an incident proton energy of 190 MeV, is fully exclusive; i.e., the protons, the neutron, and the photon have been detected. The quasifree differential cross sections obtained are compared with microscopic calculations and calculations based on soft-photon models. There are sizable differences between the models and also between the models and the data obtained for this simple process.

Direct observation of a rho decay of the D13(1520) baryon resonance.

The reaction gammap-->pi(+)pi(0)n has been measured at MAMI for photon energies up to 820 MeV. Invariant mass spectra of the particles in the final state (pi(+)n), (pi(0)n), (pi(+)pi(0)) have been determined for several bins of incident photon energy. Differences in pi(+)pi(0) and simultaneously measured pi(0)pi(0) invariant mass distributions are assigned to a rho branch of the D13(1520) nucleon resonance.

The reaction gammap-->pi0gamma'p and the magnetic dipole moment of the Delta+ 1232 resonance.

The reaction gammap-->pi(0)gamma'p has been measured with the TAPS calorimeter at the Mainz Microtron accelerator facility MAMI for energies between sqrt[s]=1221-1331 MeV. The cross section's differential in angle and energy have been determined for the photon gamma' in three bins of the excitation energy. This reaction channel provides access to the magnetic dipole moment of the Delta(+)(1232) resonance and, for the first time, a value of mu(Delta(+))=[2.7(+1.0)(-1.3)(stat)+/-1.5(syst)+/-3(theor)]mu(N) has been extracted.

In-medium modifications of the pipi interaction in photon-induced reactions.

Differential cross sections of the reactions (gamma,pi(0)pi(0)) and (gamma,pi(0)pi(+/-)) have been measured for several nuclei (1H,12C, and (nat)Pb) at an incident-photon energy of E(gamma)=400-460 MeV at the tagged-photon facility at MAMI-B using the TAPS spectrometer. A significant nuclear-mass dependence of the pipi invariant-mass distribution is found in the pi(0)pi(0) channel. This dependence is not observed in the pi(0)pi(+/-) channel and is consistent with an in-medium modification of the pipi interaction in the I=J=0 channel. The data are compared to pi-induced measurements and to calculations within a chiral-unitary approach.