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Biomedical subjects

M Heiss

Publications and source records attributed to M Heiss.

9 recordsLinked to original sources
PubMed2006

A fast online hit verification method for the single ion hit system at GSI.

For a single ion hit facility built to irradiate specific targets inside biological cells, it is necessary to prove that the ions hit the selected targets reliably because the ion hits usually cannot be seen. That ability is traditionally tested either indirectly by aiming at pre-etched tracks in a nuclear track detector or directly by making the ion tracks inside cells visible using a stain coupled to special proteins produced in response to ion hits. However, both methods are time consuming and hits can be verified only after the experiment. This means that targeting errors in the experiment cannot be corrected during the experiment. Therefore, we have developed a fast online hit verification method that measures the targeting accuracy electronically with a spatial resolution of +/-1 microm before cell irradiation takes place.

Cell Culture Techniques↗
PubMed2005

[Ambulatory dermatologic surgery].

Outpatient surgery in dermatology is likely to become increasingly important in future, for a number of reasons. Current social legislation favors outpatient surgery, because hospitals must justify performing any procedure in the outpatient catalogue on an inpatient basis. The range of conditions being treated is also broadening, for example due to the growing popularity of aesthetic enhancement procedures. Epidemiological trends in skin cancer will also lead to considerable growth in demand for outpatient dermatological surgery. This article analyses current trends in ambulatory dermato-surgery, taking into account social, legislative, hygienic, legal and economic aspects. Measures to promote quality assurance are also described. The difficult cost situation facing outpatient surgery is creating a need for new forms of cooperation between primary care physicians and hospitals.

Ambulatory Care↗
PubMed2005

Influence of hospital volume on local recurrence and survival in a population sample of rectal cancer patients.

AIMS: To investigate the role of hospital volume and individual hospitals on long term outcomes (local recurrence and survival) of rectal cancer patients. METHODS: One thousand thirty-eight patients with rectal cancer were diagnosed between 1996 and 1998. From these, we analysed 884 patients with a resected invasive primary rectal cancer. Median follow-up was 5.7 years. The impact of hospital volume (<10, 10-30 and >30 rectal cancer patients annually) on local recurrence and survival was examined in a Cox model. Differences between the four largest clinics in the high volume group were also investigated. RESULTS: In the multivariate model predicting survival the following variables were significant: UICC stage, grade, age, local recurrence, and (neo-) adjuvant therapy treatment. In the multivariate model predicting local recurrence UICC stage, tumour localisation, and neoadjuvant therapy treatment were significant variables. Hospital volume was not a significant factor for survival or local recurrence. Within the high volume category one hospital showed significantly worse local recurrence rates than all other hospitals, but no survival difference could be seen between the four largest hospitals of the high volume group. CONCLUSIONS: This analysis of a rectal cancer population found that hospital volume did not determine survival or local recurrence. Detailed clinical data with long term follow-up from cancer registries are vital to demonstrate the quality of routine care.

Aged↗
PubMed2001

Prediction of gram-negative bacteremia in patients with cancer and febrile neutropenia by means of interleukin-8 levels in serum: targeting empirical monotherapy versus combination therapy.

In a prospective observational study of 133 neutropenic episodes, interleukin (IL)-8 serum levels > 2000 pg/mL at the onset of fever had a sensitivity of 53% and a specificity of 97% as a predictor of gram-negative bacteremia (GNB; positive predictive value, 73%; negative predictive value, 94%). The rates of early death differed significantly between patients with high and those with low IL-8 levels (3/11 vs. 1/122; P< .01). Serum IL-8 levels at the onset of fever define a low-risk subgroup of patients who can safely be treated with monotherapy.

Adolescent↗
PubMed2000

[Stenoses and occlusions of the supraaortic vessels--the interdisciplinary interventional treatment of patients with an increased surgical risk].

PURPOSE: The value of elective PTA in stenoses of the supraaortic vessels and especially of the carotid artery is still under discussion. Stenoses after surgical and/or radiation therapy and a high cardio-vascular risk for a surgical procedure, however, justify minimal-invasive techniques. MATERIAL AND METHODS: In 31 patients with 24 symptomatic and 7 asymptomatic stenoses of the supraaortic arteries (3 Acc, 19 Aci, 5 Ascl, 4 Tr.brc, 2 Aax) minimal-invasive angioplasty and stent-placement was performed. The rationale for the interventional procedure was an elevated medical or technical risk of the respective surgical procedure. All procedures were performed using a coaxial technique with a guiding catheter. An open vascular access was necessary in 7 cases due to an unfavorable anatomical situation. RESULTS: The technical success rate was 100%. Peri-interventionally, a TIA occurred in 2 patients (1 spontaneous relieve, 1 complete remission after rt-PA lysis therapy). During the mean follow-up period of 13 months 3 patients died due to non-cerebrovascular reasons. In 2 patients a moderate restenosis, in 1 a high-grade stenosis, and in 1 and complete occlusion occurred without symptoms. After one year of follow-up, all treated stenoses were patent with a restenosis rate of 10.7% without further neurological symptoms. CONCLUSION: Interventional angioplasty with stent-placement of the supraaortic arteries is a safe and effective alternative in patients are at high risk for classical surgical procedures.

Adult↗
PubMed2000

Dynamic contrast-enhanced MR angiography from the distal aorta to the ankle joint with a step-by-step technique.

OBJECTIVE: The aim of this study was to visualize the arteries from the distal aorta to the ankle joint and to determine the accuracy of MR angiography for detecting stenoses and occlusions. SUBJECTS AND METHODS: Twenty-four patients with peripheral arterial occlusive disease underwent digital subtraction angiography and were examined on a 1.5-T MR scanner. The transit time for contrast material was determined with a test bolus injection. A T1-weighted three-dimensional gradient-echo sequence with short TR and TE was used for a dynamic measurement at the level of the iliac arteries, the upper leg, and the lower leg arteries. For each level a single dose of gadolinium was injected into an antecubital vein with an MR power injector. Maximal-intensity-projection reconstructions were calculated after subtraction of the first measurement at each level. Two experienced MR radiologists who were unaware of the digital subtraction angiography results interactively evaluated both the MIP reconstructions and the single slices on a workstation, first independently and then in a consensus interpretation. RESULTS: With digital subtraction angiography, 80 hemodynamically significant stenoses and 39 occlusions were detected. For the stenoses and occlusions, a sensitivity of 100% was found for MR angiography. The specificity for the assessment of stenoses and occlusions was 98% and 94%, respectively, for the iliac arteries; 98% and 94%, respectively, for the upper leg arteries; and 94% and 95%, respectively, for the lower leg arteries. Most false-positive findings of occlusion were due to metal stents present in the iliac (n = 3) and upper leg (n = 4) arteries. CONCLUSION: The MR imaging technique that we used revealed the arteries from the distal aorta to the ankle and proved to be reliable at showing arterial stenoses and occlusions.

Aged↗
PubMed1999

Myelodysplastic syndrome with monosomy 7 after immunosuppressive therapy in Behçet's disease.

Only few cases of Behçet's and hematological malignancies have been reported until now. We recently observed a 39-year-old female patient with Behçet's disease developing a myelodysplastic syndrome (MDS) FAB subtype refractory anemia with excess of blasts in transformation [RAEB-t] with a monosomy 7 after being treated with cyclosporin A and chlorambucil for several years. This case is reported and the occurrence of hematological malignancies and Behçet's disease is reviewed.

Adult↗
PubMed1986

Simultaneous demonstration of two antigens on single T cells using antibodies with contrasting labels.

We describe a double labeling method for the discrimination of 2 antigens on single cells. It consists of a combination of 3H-immunoautoradiography and immunocytochemistry applied to cells previously fixed on poly-L-lysine (PLL)-coated multispot slides. The method has been applied to various mouse cells contemporaneously labeled with 2 different monoclonal antibodies. In order to distinguish the attached antibodies unambiguously, they were labeled with contrasting markers. One of the antibodies was marked with tritium blackening the photographic film that covers the slide. The other was detected with the peroxidase-anti-peroxidase (PAP) method forming a reddish precipitate. The contrast between the reddish reaction product of the PAP-labeled antibody and the black silver grains allows cells, specifically labeled with both antibodies, to be distinguished from cells labeled with only one or neither of the antibodies. Tritium-labeled antibodies were introduced because of their advantage over antibodies labeled with iodine in the closer localization of the silver grains to the bound antibody and their much longer halflife (60 days versus 12 years). In this study we applied a tritium-labeled anti-Thy-1.1 together with anti-Lyt-1 monoclonal antibody for studying the distribution of the corresponding antigens on lymphocytes in the mouse thymus and lymph node cells.

Animals↗