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M Hartmann

Publications and source records attributed to M Hartmann.

At least 37 records · Page 2Linked to original sources
PubMed2005

Measurement of the analyzing power in p-->d-->(p p)n with a fast forward 1S0 proton pair.

A measurement of the analyzing power A(y) of the p-->d--> (p p) + n reaction was carried out at the ANKE spectrometer at COSY at beam energies of 0.5 and 0.8 GeV by detection of a fast forward proton pair of small excitation energy E(pp) < 3 MeV. The S-wave dominance in the fast diproton is experimentally demonstrated in this reaction. While at T(p) = 0.8 GeV the measured analyzing power almost vanishes, it rises to nearly unity at T(p) = 0.5 GeV for neutrons emitted at theta(c.m.)(n) = 167 degrees. The results are compared with a model taking into account one-nucleon exchange, single scattering, and Delta(1232) excitation in the intermediate state. The model describes fairly well the unpolarized cross section obtained earlier and the analyzing power at 0.8 GeV; it fails to reproduce A(y) at 0.5 GeV.

Journal Article↗
PubMed2005

Electron spin resonance studies of Cu(I)-NO complexes formed over copper-exchanged three- and unidimensional zeolites.

Cu(I)-NO complexes, one of the essential intermediates in the NO decomposition reaction, were formed over copper exchanged and autoreduced Cu-ZSM-5, Cu-MCM-58, Cu-ZSM-12, and Cu-L zeolites, and studied by electron spin resonance spectroscopy at X-, Q-, and W-band frequencies. The spin Hamiltonian parameters of the NO adsorption complexes formed over pretreated materials firmly confirm the formation of Cu(I)-NO moieties. Two different Cu(I)-NO species A and B that are formed on account of different numbers of framework oxygen atoms coordinating to the Cu(I) cation are observed for Cu-ZSM-5, Cu-MCM-58, and Cu-ZSM-12 zeolites, while formation of a single Cu(I)-NO species B is observed in Cu-L zeolite. On the basis of the isotropic copper hyperfine couplings and the different channel topologies of the studied zeolite frameworks, we assign species A and B to Cu(I)-NO complexes formed at M5(7)-type and I2-type Cu(I) cation sites with either three or two oxygen co-ligands, respectively, supporting the results of previous quantum chemical studies on the Cu-ZSM-5 reference system. Whereas accessible five- or six-membered rings are clearly a prerequisite for M5(7)-type Cu(I) adsorption sites, the formation of I2-type sites in the unidimensional Cu-MCM-48, Cu-ZSM-12, and Cu-L zeolites suggests that not just channel intersection but also other structural motifs with exposed AlO4 tetrahedra can constitute such I2-type sites provided that sufficiently large channels can freely accommodate the Cu(I)-NO species.

Journal Article↗
PubMed2005

[Rashes in HIV-infected patients undergoing therapy with nevirapine or efavirenz].

Efavirenz and nevirapine are frequently used drugs in antiretroviral therapy. Rashes are common side effects of these drugs. In this study, we examined the characteristics of efavirenz- and nevirapine-associated rashes. This prospective nonrandomized multicenter study included 662 HIV-infected patients (efavirenz: 325, nevirapine: 337) to determine incidence, duration, cross-reactivity, and outcome upon reexposure. Of the treated patients, 4.5% (n=30) developed rashes (nevirapine: 2.4% and efavirenz: 6.4%). In four patients treatment was not interrupted. Three patients were re-exposed to the initial drug without any side effects. Therapy with nevirapine or efavirenz does not have to be interrupted if rashes exhibit no blistering, mucosal manifestations, or systemic signs.

Alkynes↗
PubMed2005

[Magnetic resonance spectroscopy of brain tumours].

Magnetic resonance spectroscopy facilitates non-invasive determination of metabolic changes in vivo. The main metabolites are the neuronal marker N-acetylaspartate (NAA), cholines reflecting membrane turnover, creatine, lactate, and mobile lipids. Primary brain tumours exhibit reduced NAA and increased choline resonances compared to normal brain, and these abnormalities increase with higher malignancy. Increasing choline resonances on follow-up studies correlate with tumour progression, whereas the reduction of initially increased choline resonances indicates a transition from viable tumour to necrotic tissue. Metastases as non-neuroectodermal tumours lack NAA, but demonstrate elevated choline, lactate and lipid resonances. Lymphomas are characterised by massively increased lipid resonances with markedly elevated choline. Prominent alanine resonances are often observed in meningioma. Cystic/necrotic lesions demonstrate elevated lactate regardless of their aetiology. The characteristic finding of prominent resonances from acetate, succinate, and alanine, of leucine, isoleucine and valine in untreated bacterial abscesses allows the differentiation of bacterial abscesses from cystic/necrotic brain tumours.

Biomarkers, Tumor↗
PubMed2005

Differences in reporting of acute rejections between American and European publications of large immunosuppressive trials impair comparability of study results.

This study examined the use of different definitions for acute rejection in recent large multicenter trials performed in America and Europe in order to assess whether systematic differences exist between both scientific cultures. We systematically selected recent publications on multicenter randomized controlled trials, investigating immunosuppressive regimens in de novo kidney transplant recipients. Publications included were classified according to the type of acute rejection reported: group 1 reported no or only one type of rejection rate (biopsy-proven or treated); group 2 reported information on both treated and biopsy-proven rates. Other potential factors (journal's impact-factor, study size) were compared within the subgroups. To determine the rates of treated but not biopsy-proven acute rejections, additional analyses were performed within subgroup 2. The reviewed publications were 24/44 (54.5%) European (E) and 20/44 (45.5%) American (A) origin. Eighteen of 44 publications reported no or only one type of rejection rate (group 1); 26 publications reported treated as well as biopsy-proven rates (group 2). Significantly more European publications reported both treated and biopsy-proven rates (E: 18/24 [75.0%] vs A: 8/20 [40.0%]; P = .019). Group 1 American papers were published in higher-ranked journals than European ones. The rate of blindly treated rejections did not differ significantly (A: 6.13% [range 0% to 12.8%] vs E: 8.43% [range 0% to 16.9%]) and the proportion of blindly treated rejections was slightly lower in American studies (A: 18.5% vs E: 26.5%). Our systematic review showed large discrepancies with a trend to report biopsy-proven rejection rates only in recent years.

Acute Disease↗
PubMed2005

[Pseudonormalization of diffusion weighted images: magnetic resonance imaging in an animal model (C6-glioma)].

PURPOSE: Previous studies on intracranial tumors indicate that a high apparent diffusion coefficient (ADC) is due to low cellularity and that lower values indicate a dense, highly cellular tumor. Diffusion is affected by three major factors: cell density, existence and distribution of vasogenic edema, and hypoxic tissue. Therefore, we studied the characteristics of diffusion-weighted magnetic resonance imaging (DWI) in a rat brain C6 glioma during tumor progression. MATERIALS AND METHODS: In male Wistar rats, C6 gliomas were implanted in the caudoputamen. At day 9, 11, 13 and 15 after tumor inoculation, conventional DWI was performed on a 2.35 Tesla small bore MRI unit (Biospec 24/40, BRUKER Medizintechnik, Ettlingen, Germany). RESULTS: On conventional T2-weighted and contrast-enhanced T1-weighted images, all tumors could well be delineated from the surrounding brain tissue and showed significant progression. On DWI, the tumors were isointense or slightly hypointense compared to the surrounding brain. On the ADC maps, the tumors could be well visualized due to increasing ADC values from day 9 to 15. The mean ADC of brain tumor tissue was 0.76 +/- 0.4 x 10 ( - 3) mm (2)/s at day 9 and 0.91 +/- 0.03 x 10 ( - 3) mm (2)/s at day 15. The mean ADC of the normal contralateral caudoputamen was 0.59 +/- 0.007 x 10 ( - 3)mm (2)/s. CONCLUSION: T2 prolongation and increased water diffusion can be balanced on DWI in C6 gliomas, resulting in isointensity on DWI (T2 shine-through washout phenomenon). ADC maps are indispensable for the correct interpretation of tumor tissue diffusion behavior.

Animals↗
PubMed2005

Mycophenolate mofetil and skin diseases.

Mycophenolate mofetil (MMF) is an immunosuppressive drug the efficiency of which has been established in renal transplantation. Recent studies suggest that it may also be effective in the treatment of variant skin diseases especially if the skin lesions are triggered by lymphocytes. Studies have shown efficacy in autoimmune bullous dermatoses, atopic dermatitis and psoriasis. However, there are no placebo-controlled trials that support the use of MMF as first line therapy in these skin diseases.

Dermatitis, Atopic↗
PubMed2004

Residual tumor resection after high-dose chemotherapy in patients with relapsed or refractory germ cell cancer.

PURPOSE: To assess the role of residual tumor resection performed after high-dose chemotherapy (HDCT) in patients with relapsed or refractory germ cell tumors (GCT). PATIENTS AND METHODS: Between July 1987 and October 1999, postchemotherapy resections of residual tumors were performed in 57 patients who had been treated with HDCT for relapsed or refractory GCT and who had achieved a partial remission to this treatment. RESULTS: Complete resections of residual masses were achieved in 52 (91%) of 57 patients who were rendered disease free; in five (9%) of 57 patients, the resections were incomplete. Resection of a single site was performed in 39 (68%) of 57 patients, and the remaining 18 (32%) of 57 patients required interventions at two or more residual tumor sites. Necrosis was found in 22 (38%) of 57 patients, mature teratoma with or without necrosis was found in nine (16%) of 57 patients, and viable cancer with or without additional necrosis or mature teratoma was found in 26 (46%) of 57 patients. Viable cancer consisted either of residual germ cell or undifferentiated cancer in 22 (85%) of 26 patients, with additional non-GCT histologies in the remaining four patients. Patients with viable cancer had a significantly inferior outcome after surgery compared with patients with necrosis and/or mature teratoma even if all cancer was completely resected. Pulmonary lesions with a diameter of more than 2 cm were the only predictive variable for viable cancer in univariate analysis. CONCLUSION: Resections of all residual tumors should be attempted in patients with relapsed or refractory GCT and partial remissions after HDCT.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Does acute occlusion of the carotid T invariably have a poor outcome?

OBJECTIVE: To evaluate the prognosis of patients with acute occlusion of the carotid T. METHODS: The authors studied 42 consecutive patients with acute carotid T occlusion, age 66 (59 to 74) years (median [interquartile range]). T occlusion was diagnosed with transcranial Doppler sonography (TCD; n = 11) and MR (n = 28) or CT (n = 3) angiography. Final infarction size was evaluated on follow-up CT 3 to 7 days after symptom onset and recanalization by follow-up TCD 24 to 36 hours after symptom onset. RESULTS: NIH Stroke Scale (NIHSS) score on admission was 18 (16 to 20). Final infarct size was one-third or less of the middle cerebral artery (MCA) territory in 11, greater than one-third but less than or equal to two-thirds of the MCA territory in 10, and greater than two-thirds of the MCA territory in 21 patients. Modified Rankin Scale (mRS) score 6 months after stroke onset was 2 in 7 (17%), 3 in 2 (5%), 4 in 13 (31%), 5 in 7 (17%), and 6 in 13 (31%) patients. Complete or partial MCA recanalization within 24 hours after symptom onset was observed in 12 of 18 patients treated with thrombolysis and 4 of the remaining 24 patients (p = 0.001) and was associated with better clinical outcome (mRS 2, recanalization 6/7 [86%]; mRS 3 to 5, recanalization 8/22 [36%]; mRS 6, recanalization 2/13 [15%]; p = 0.01). Recanalization and NIHSS score on admission were independent predictors of outcome. CONCLUSIONS: Acute carotid T occlusion does not necessarily carry a poor prognosis. IV thrombolysis frequently results in recanalization, which is related to a better clinical outcome and smaller final infarction size.

Acute Disease↗
PubMed2004

Small vessel stents for intracranial angioplasty: in vitro evaluation of in-stent stenoses using CT angiography.

Our aim was to determine whether CT angiography is suitable for the evaluation of in-stent restenoses in small vessel stents for intracranial angioplasty. Therefore, we simulated stenoses with degrees of 25, 50, 75 and 90% in a total of 12 stents with different designs (MEDTRONIC AVE; ABBOT BioDivYsio, GUIDANT Neurolink, TERUMO Tsunami, COOK V-Flex Plus) and sizes (3.0 mm, 4.0 mm). For each stenosis, the apparent stenotic degree (ASD) was measured by CT angiography. Subjective (viewing at the CT images) and objective (acquisition of a density profile) evaluations were made after the stents were filled with a solution of 0.9% NaCl and with a diluted contrast medium. It was not possible to visualize the patent lumen in any of the stenotic stent segments by viewing at the CT images. After objective evaluation, the degree of the stenoses was generally overestimated. In the group with the 3.0-mm stents, ASD ranged from 73.6 to 100% in 25% degree stenoses. With the exception of one stent, stenoses with a degree of more than 25% appeared as vessel obstruction (ASD = 100%) in the 3.0-mm group. In the 4.0-mm group, the mean ASD was 60% for 25% degree stenoses, 76% for 50% degree stenoses, 91% for 75% degree stenoses and 96% for 95% degree stenoses. The minimum diameter of stents for differentiation between in-stent restenosis and vessel occlusion using CT angiography is 4.0 mm. In CT angiography, the degrees of in-stent stenoses are generally overestimated. The evaluation of in-stent restenoses only seems to be possible when CT angiographic images before and after contrast application are evaluated objectively by density profiles.

Angioplasty, Balloon↗
PubMed2004

[Syphilis--diagnosis, treatment and characteristics in HIV-infected patients].

Venereal syphilis is a chronic cyclic infectious disease that, if untreated, runs a decades-long course. The responsible pathogen is Treponema pallidum. Clinically, a differentiation is made into early (primary) syphilis (up to 1 year following infection, syphilis I), during which disease manifestations are localized, secondary syphilis (syphilis II) with generalized manifestations, and late, or tertiary syphilis (syphilis III). Clinical manifestations that have been observed in HIV patients are syphilis maligna and neurosyphilis. Treatment of choice continues to be penicillin. Instead of only a single injection of penicillin, HIV infected patients with early syphilis should be given three injections, with an interval of 1 week between them, to prevent the development of neurosyphilis.

AIDS-Related Opportunistic Infections↗
PubMed2004

Characterization of necrotic meningioma using diffusion MRI, perfusion MRI, and MR spectroscopy: case report and review of the literature.

Necrotic meningiomas are relatively rare, accounting for 1.3-3.9% of primary intracranial tumours and for 10-15% of meningiomas, but are of special clinical importance as they may resemble metastases or malignant gliomas. We report the magnetic resonance findings of diffusion-weighted imaging, perfusion-weighted imaging, and spectroscopy in a patient with a necrotic meningioma, in whom clinical symptoms and signs suggested a central nervous system infection.

Adult↗
PubMed2004

[Superficial siderosis of the CNS. 2 cases and a review of the literature].

Superficial siderosis of the CNS is a rare disease. The superficial deposition of haemosiderin in the cerebrum, cerebellum and spinal cord is due to chronic and recurrent subarachnoidal haemorrhage (SAH). Known sources of bleeding are vascular CNS-tumours, CSF-cavity lesions, vascular malformations, nerve root lesions and neurosurgical interventions. Detection of the source of bleeding is successful in only about 50% of cases. The clinical syndrome is characterized by sensorineural deafness, cerebellar ataxia and pyramidal signs. CSF-investigation might be indicative for SAH, while ferritin and ionic iron can be elevated in the CSF. CT is unspecific and insensitive but MR imaging of the brain and spinal cord is very sensitive and specific. The elimination of the source of bleeding alone might prevent the progression of the disease, therefore, an early and extensive search for this source is highly recommended.

Central Nervous System Diseases↗
PubMed2004

[Symptomatic dissection of the internal carotid artery. A rare manifestation of autosome dominant polycystic kidney disease?].

Autosomal dominant polycystic kidney disease (ADPKD) is a frequent, genetically heterogenous disease with renal and extrarenal manifestations. Intracranial aneurysms are found in about 10% of cases. Other vascular manifestations of ADPKD have been described only in small case series. We report a 44-year-old ADPKD patient who developed acute large middle cerebral artery infarction secondary to subpetrous dissection of the internal carotid artery. Six months after the stroke, pseudoaneurysm was demonstrated on magnetic resonance angiography at the site of a previous dissection. Based on this case report, we review the spectrum of neurovascular manifestations and stroke associated with ADPKD and summarize current concepts of the pathogenesis of this disease. Finally, special aspects of the diagnostic evaluation and therapeutic management in patients with ADPKD and cervicocephalic dissection are discussed.

Aneurysm, False↗
PubMed2004

Fatal subarachnoid hemorrhage after carotid stenting.

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome with intracerebral hemorrhage (ICH) following carotid angioplasty and stent placement (CAS) of the internal carotid artery (ICA) is well known. We report the occurrence of fatal subarachnoid hemorrhage in a patient undergoing CAS. CASE REPORT: A 77-year-old woman experiencing a left-hemispheric transient ischemic attack underwent CAS for a 95% stenosis of the left ICA. CAS was performed without acute complications. At 5 hours the patient suddenly deteriorated. Her level of consciousness changed and she developed neck stiffness. CT of the brain revealed diffuse SAH with acute hydrocephalus. CONCLUSIONS: Like ICH, SAH may develop as a severe complication after CAS. There are no reliable clinical symptoms preceding this fatal complication. However, several factors such as long-standing severe carotid stenosis with contralateral occlusion and increasing blood pressure after CAS accompanied by the extensive use of antithrombotic agents may predispose to this fatal complication.

Aged↗
PubMed2004

[Tumor simulating lesions on cranial MR imaging].

Statistically tumors are the most likely cause of space-occupying intracranial lesions. However, many non-neoplastic diseases also manifest as mass lesions and may be indistinguishable from tumors. The most common of these are inflammatory and dysplastic lesions, which intraaxially imitate mostly glioma, lymphoma, and metastases and extraaxially meningeoma and neurinoma. Aside from a willingness on the part of the diagnostic radiologist to question the most obvious diagnosis, on clinical history and findings are prerequisites for a sound radiological differential diagnosis. The aim of this article is to provide a practical overview of the differential diagnosis of intracranial mass lesions with emphasis on non-neoplastic abnormalities.

Adult↗
PubMed2004

[Effect of enteral naloxone on the incidence of gastritis and esophagitis in mechanically ventilated patients].

BACKGROUND: Gastrtis and esophagitis are frequent and severe complications in intensive care patients, mainly caused by increased duodenogastral reflux. Opioids, commonly used in intensive care, are known to impair gastrointestinal (GI) motility which increases retrograd flow of gastric content. In a previous study, we showed that enteral administered naloxone reduces gastric reflux by selectively blocking GI opioid receptors. Therefore, in a subpopulation of these patients we studied the effect of enteral naloxone on the incidence of mucosal injury in opioid-treated, mechanically ventilated patients. METHODS: After IRB approval, mechanically ventilated, fentanyl-treated patients without gastrointestinal surgery or diseases were assigned to receive 8 mg naloxone or placebo four times daily via a gastric tube. Additional inclusion criteria were opioid treatment for at least three days and endoscopy of the upper GI tract. Frequency of gastritis and esophagitis was quantified according to the Savary-Miller Score, and further parameter of GI motility (frequency of propulsive medication, amount of enteral feeding) were measured. RESULTS: In four of seventeen patients of the naloxone group (24 %) and 14 of 22 patients of the placebo group (64 %; p = 0.02), esophageal or gastral mucosal injuries were detected. In the naloxone group, gastral reflux as well as need for propulsive medication were significantly lower. Volume of enteral feeding showed an increasing trend in the second half of the study. CONCLUSION: Reduction of esophagogastral mucosal injury and reduced need for procinetic medication suggests an improvement of GI motility by enteral naloxone in fentanyl-treated, mechanically ventilated patients.

Adult↗