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Biomedical subjects

M Zimmermann

Publications and source records attributed to M Zimmermann.

At least 37 records · Page 2Linked to original sources
PubMed2004

New limits on the drift of fundamental constants from laboratory measurements.

We have remeasured the absolute 1S-2S transition frequency nu(H) in atomic hydrogen. A comparison with the result of the previous measurement performed in 1999 sets a limit of (-29+/-57) Hz for the drift of nu(H) with respect to the ground state hyperfine splitting nu(Cs) in 133Cs. Combining this result with the recently published optical transition frequency in 199Hg+ against nu(Cs) and a microwave 87Rb and 133Cs clock comparison, we deduce separate limits on alpha/alpha=(-0.9+/-2.9) x 10(-15) yr(-1) and the fractional time variation of the ratio of Rb and Cs nuclear magnetic moments mu(Rb)/mu(Cs) equal to (-0.5+/-1.7) x 10(-15) yr(-1). The latter provides information on the temporal behavior of the constant of strong interaction.

Journal Article↗
PubMed2004

Robot-assisted navigated endoscopic ventriculostomy: implementation of a new technology and first clinical results.

BACKGROUND: Important landmarks in the evolution of advanced neurosurgical techniques during the past decades include microneurosurgery, neuro-endoscopy and its minimally invasive nature, as well as neuronavigation and advanced intra-operative imaging. With conventional neuroendoscopic techniques, e.g. free-hand endoscopy or the use of mechanical or pneumatic holding devices, a definitive and controlled movement of the endoscope within the brain does depend on the experience and manual skill of the individual neurosurgeon. Therefore, the development of robotic systems to assist surgeons in performing complex neurosurgical procedures is a growing field of interest. METHOD: With the precision robot "Evolution 1" (U.R.S. Universal Robot Systems, Schwerin, Germany) a new neurosurgical tool has just become available for the precise steering of instruments within the cranium. After preclinical anatomical as well as precision studies the system was used for robot-assisted navigated endoscopic third ventriculostomies in six patients with hydrocephalus related to aqueductal stenosis. FINDINGS: All robot-assisted navigated endoscopic procedures were successfully completed. The time for the registration procedure and setup of the robot decreased from 60 min. for the first procedure down to 30 min. The time for the surgical part of the neuro-endoscopic procedure itself ranged from 17 to 35 min. During all procedures no system-related complications occurred. INTERPRETATION: The use of robotic technology for neuro-endoscopic third ventriculostomies is a major step towards the controlled movement of the neuro-endoscope within the cranium. The start up procedure and calibration of the robot is still time consuming, but the real operation time is comparable to free hand neuro-endoscopy. The steering of the endoscope is facilitated and the precision of the endoscopic movements is noteworthy.

Adolescent↗
PubMed2004

Clivus lymphoma.

Lymphoma as primary infiltration of the skull base, especially the clivus, is unusual and rare. However, increasing incidence of atypical lymphoma manifestations have been reported. As cranial base surgery becomes more common, it is important to be aware of lymphoma as a possible differential diagnosis of clivus lesions. This case presents a primary malignant lymphoma of the clivus, histologically confirmed after intra-operative MRI-guided transnasal-transsphenoidal biopsy.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Severe delayed diffuse cerebral vasospasm and cerebral infarctions following spinal subdural hemorrhage.

BACKGROUND: We report a rare case of severe delayed cerebral vasospasm with cerebral infarctions after spinal subdural hemorrhage. CASE REPORT: A 56-year-old woman presented with an acute onset of paraplegia. MR-imaging revealed an extensive intraspinal hemorrhage reaching from T1 to L1. The hematoma was evacuated via a T8-laminectomy. At the 7th postoperative day the patient developed visual disturbances. MR-scanning revealed extensive infarctions and cerebral angiography showed severe diffuse vasospasms. INTERPRETATION: This case demonstrates that cerebral vasospasm may be caused by a spinal subdural hemorrhage, supporting the hypothesis that cerebral vasospasm may be triggered by factors from a remote site and that a direct contact of blood clots with the vessel is not mandatory.

Cerebral Infarction↗
PubMed2004

Platelet APP, ADAM 10 and BACE alterations in the early stages of Alzheimer disease.

Amyloid precursor protein (APP), ADAM 10, and beta-site-APP cleaving enzyme (BACE) alterations were evaluated in platelets of 31 patients with Alzheimer disease (AD) and 15 age-matched controls. A significant modification of these proteins and enzymes involved in the amyloid cascade was detected from the earliest clinically detectable disease stage. This observation suggests that AD is associated with an early metabolic derangement toward amyloidogenic pathways and supports the potential value of APP and secretase measurements for early diagnosis of AD.

ADAM Proteins↗
PubMed2004

[Chronic pain. Epidemiology and management in Germany].

At least 5 million patients with chronic and severely debilitating pain exist among the adult population in Germany, i.e. 8% of this population. Various biological and psychosocial risk factors contribute to the continuing chronicity of pain, resulting in enormous direct and indirect costs totalling an estimated 38 billion euro annually. The introduction of a medical specialty for pain treatment in 1998 has not appreciably affected the quality of outpatient pain management. In contrast, more recent approaches of multimodal treatment, including medical, psychological and behavioral components, have shown a significant and lasting effect in patients with a high incidence of workplace incapacitation and sick leave. In particular, the GRIP pilot project (Göttingen Intensive Back Project) has resulted in an increased rate (to 200%) of return to the workplace and in a decrease in health system expenses to 50% of the pretreatment level.

Back Pain↗
PubMed2004

[Neuronal mechanisms of chronic pain].

Until recently the paradigms of pain research were predominantly related to acute pain in humans and animals. Some 20 years ago the focus of basic and clinical research was shifted towards the mechanisms of chronic pain. Usually the nociceptors of our joints respond only to overload and lesions and thus serve protective functions. However, in case of a lasting pain condition mechanisms emerge in the nervous system that result in an increasing sensitivity of the neuronal pain system-these are the initial steps toward the process of pain chronicity. Inflammatory mediators including cytokines result in a dramatic enhancement of peripheral nervous system sensitivity. The ensuing plastic changes in the central neurotransmitter systems result in long term potentiation of synaptic transmission and may include adaptations in neuronal gene transcription. Interactions between the nervous and immune systems as well as learning processes may further wind up pain sensitivity. The tendency of perpetuation inherent to these processes contribute to pain chronicity-can this be halted by preventive treatment strategies?

Animals↗
PubMed2004

[The use of regional anesthesia in orthopedics].

Regional anesthesia has its place in the perioperative pain management of orthopedic patients. A reduction in postoperative mortality and morbidity with regional anesthesia is acknowledged for subsets of patient populations. Single shot and continuous applications are techniques for providing regional analgesia. Continuous infusion of local anesthetics with catheter techniques provides for uninterrupted postoperative analgesia. The combination of regional and general anesthesia reduces the consumption of systemic anesthetics. The side effects of opioid therapy are thereby reduced. The inhibition of intraoperative stress reaction, especially with epidural anesthesia, helps to prevent or lower unwanted metabolic changes. Patient contentment with analgesic quality differs with the technique with which the regional anesthesia is applied (PDA, PCEA, IVRA, peripheral block, i.a. injection), and the medication (LA, opioid) used.

Anesthesia, Conduction↗
PubMed2004

Modern diagnostics in chronic myeloproliferative diseases (CMPDs).

According to the new WHO classification a group of chronic myeloproliferative diseases (CMPDs) were defined: chronic myeloid leukemia (CML), chronic neutrophilic leukemia (CNL), chronic eosinophilic leukemia and hypereosinophilic syndrome (CEL/HES), polycythemia vera (PV), chronic idiopathic myelofibrosis (with extramedullary hematopoiesis, CIMF), essential thrombocythemia (ET), and so called CMPD/unclassifiable. As clinical features and laboratory findings differ widely between these diseases several diagnostic approaches are mandatory at diagnosis for classification and are needed also for follow up studies, especially for the measurement of minimal residual disease (MRD). We here outline the laboratory set up at diagnosis and during follow up in CMPDs with specific focus on the respective therapeutical consequences. Only by using a comprehensive diagnostic panel including cytomorphology, cytogenetics, and molecular genetic methods establishing the correct diagnosis, optimizing treatment as well as evaluating treatment response is possible in CMPDs today.

Blood Cell Count↗
PubMed2004

Iodine supplementation of pregnant women in Europe: a review and recommendations.

OBJECTIVE: Nearly two-thirds of the population of Western and Central Europe live in countries that are iodine deficient. Damage to reproductive function and to the development of the fetus and newborn is the most important consequence of iodine deficiency. The objective of this review was to examine the iodine status of pregnant women in Europe and the potential need for iodine supplementation. DESIGN: A MEDLINE/PubMed search and compilation of all published studies since 1990 of iodine nutrition and iodine supplementation of pregnant women in Europe, as well as an Internet-based search and review on availability and legislation of iodine supplements in the European Union. RESULTS: Although the data suggest most women in Europe are iodine deficient during pregnancy, less than 50% receive supplementation with iodine. Mild-to-moderate iodine deficiency during pregnancy adversely affects thyroid function of the mother and newborn and mental development of the offspring and these adverse effects can be prevented or minimized by supplementation. There are no published data on the effect of iodine supplementation on long-term maternal and child outcomes. The iodine content of prenatal supplements in Europe varies widely; many commonly used products contain no iodine. The European Union is developing legislation to establish permissible levels for iodine in food supplements. CONCLUSIONS: In most European countries, pregnant women and women planning a pregnancy should receive an iodine-containing supplement ( approximately 150 microg/day). Kelp and seaweed-based products, because of unacceptable variability in their iodine content, should be avoided. Prenatal supplement manufacturers should be encouraged to include adequate iodine in their products. Professional organizations should influence evolving EU legislation to ensure optimal doses for iodine in prenatal vitamin-mineral supplements. SPONSORSHIP: International Council for Control of Iodine Deficiency Disorders.

Adult↗
PubMed2004

Experimental approaches to evaluate endothelin-A receptor antagonists.

A large body of evidence suggests a substantial role of the endothelin (ET) system in the pathophysiology of a variety of disease states, mainly of the cardiovascular system. Recently bosentan, an ET receptor antagonist, has received approval by the Food and Drug Administration (FDA) for use in pulmonary artery hypertension. The ET system may also be involved in cerebrovascular disorders such as stroke and, most notably, development of cerebral vasospasm following subarachnoid hemorrhage. The pathophysiological mechanisms contributing to the development of a cerebral vasospasm after subarachnoid hemorrhage may be taken as a paradigm to explore mechanisms leading to secondary ischemic brain damages in a variety of insults such as stroke and trauma. The present review provides the evidence to evaluate ET receptor antagonists for potential prophylactic and therapeutic use in patients suffering from subarachnoid hemorrhage. The rationale to develop selective ETA receptor antagonists is given with respect to basic and applied studies. This may be useful to better define the desired profile of action of a given compound, and it may also help to design appropriate preclinical and clinical trials, most desirably in close cooperation with pharmaceutical companies and neurosurgical departments.

Animals↗
PubMed2003

Development of a bisphenol A-adsorbing yeast by surface display of the Kluyveromyces yellow enzyme on Pichia pastoris.

A novel surface-engineered strain of yeast Pichia pastoris was constructed that displays at its surface Kluyveromyces lactis Yellow Enzyme (KYE) fused to the C-terminal half of Saccharomyces cerevisiae alpha-agglutinin. The expression of the fusion protein was controlled by the AOX1-promoter. The new strain showed an increased sorption of the xenoestrogen Bisphenol A (BPA). It was shown that sorption of BPA depended on the presence of methanol in the growth medium and on the pH of the binding assays. The binding kinetics were typical for binding at a surface. The present results demonstrate that the alpha-agglutinin surface display system can be used in the yeast P. pastoris.

Adsorption↗
PubMed2003

Primary mediastinal large B-cell lymphoma with sclerosis in pediatric and adolescent patients: treatment and results from three therapeutic studies of the Berlin-Frankfurt-Münster Group.

PURPOSE: Primary mediastinal large B-cell lymphoma with sclerosis (PMLBL) is a rare entity of non-Hodgkin's lymphoma (NHL) arising from thymic mature B cells. Optimal treatment strategies remain to be established, especially in pediatric patients. PATIENTS AND METHODS: This study analyzes clinical characteristics and treatment outcome of 30 pediatric patients with PMLBL, diagnosed in multicenter therapy NHL-Berlin-Frankfurt-Münster Group (BFM) trials. Treatment was stratified by stage and serum lactate dehydrogenase (LDH) and consisted of four to six 5-day courses of chemotherapy using steroids, oxazaphosphorine alkylating agents, methotrexate, cytarabine, etoposide, and doxorubicin. Radiation was not part of the protocol. RESULTS: From April 1986 to August 1999, 1,650 patients with newly diagnosed NHL were enrolled in the NHL-BFM trials; 30 patients (1.8%) had PMLBL. Median age was 14.3 years (range, 1.4 to 16.7 years); 15 patients were male and 15 patients were female. With a median observation time of 5 years (range, 1 to 12 years), probability of event-free survival (pEFS) at 5 years was 0.70 (SE, 0.08). Two patients erroneously diagnosed as T-cell NHL received non-B-cell therapy and died from progress of disease. Events in 28 patients receiving B-cell therapy included early progress during therapy (n = 1) and relapse (n = 6). Residual mediastinal masses were present in 23 patients after two courses of therapy and in 15 patients after the end of therapy. LDH > or = 500 U/L was associated with increased risk of failure in multivariate analysis. CONCLUSION: PMLBL mainly is found in adolescents. Dose-intense chemotherapy including high-dose methotrexate yields a pEFS at 5 years of 0.70 (SE, 0.08). LDH is of prognostic value in pediatric patients with PMLBL.

Adolescent↗
PubMed2003

Glucose oxidation by Gluconobacter oxydans: characterization in shaking-flasks, scale-up and optimization of the pH profile.

In this study, the advantage of a novel measuring device for the online determination of oxygen and carbon dioxide transfer rates in shaking-flasks is reported for glucose oxidation by Gluconobacter oxydans. In this fermentation process, this device was used for the characterization of the oxidation pattern of different strains. G. oxydans NCIMB 8084 forms 2,5-diketogluconate from d-glucose in a multi-stage process via three different membrane-bound dehydrogenases. This strain was chosen for a scale-up of the process from shaking-flasks to a 2-l stirred vessel. An enhancement of 2,5-diketogluconate production was realized by controlling the pH at different levels during the fermentation.

Biotechnology↗