Biomedical subjects

Harald Müller

Publications and source records attributed to Harald Müller.

5 recordsLinked to original sources

PubMed2004

Neuroprotection by hyperbaric oxygenation after experimental focal cerebral ischemia monitored by MRI.

BACKGROUND: Hyperbaric oxygenation (HBO) after focal cerebral ischemia reduces infarct size and improves outcome when applied early after stroke. Here, we evaluated effects of HBO on permanent focal cerebral ischemia and applied magnetic resonance imaging (MRI) monitoring to study lesion evolution. METHODS: Rats underwent permanent middle cerebral artery occlusion (MCAO). Two hours later, animals were treated with HBO (100% O(2)/2 atm; n=17) for 1 hour or treated with room air (n=17). Animals underwent serial MRI studies (DWI, PI, T2) beginning 90 minutes after MCAO. Neuroscore was assessed (5-point rating scale). Animals were euthanized and brains were 2,3,5-triphenyltetrazolium chloride (TTC)-stained for infarct volume calculation 120 hours after MCAO. Immunohistochemistry was performed with antibodies against c-FOS and 4-hydroxy-2-nonenal-modified proteins (HNE) to check for effects of oxidative stress caused by HBO treatment. RESULTS: HBO reduced infarct volume by 38% (P<0.001). As shown by MRI, neuroprotection began 5 hours after ischemia and remained effective for 5 days. The relative regional cerebral blood flow was not different between groups at 3.5 and 5 hours after occlusion. There was less neurological deficit in HBO-treated animals compared with controls (P<0.05). Lipid peroxidation of cerebral vessels after HBO treatment as measured by HNE staining and pattern of c-FOS induction were not significantly different between groups at 3.5 and 8 hours after ischemia. CONCLUSIONS: As monitored by MRI HBO treatment reversed ischemic lesion size between 3 and 5 hours after ischemia and achieved a long-lasting neuroprotective effect without significant oxidative damage.

Animals↗

PubMed2003

Differentiation of isomeric sulfur heterocycles by electron ionization mass spectrometry: 1,4-dithiins, 1,4-dithiafulvenes and their analogues tetrathianaphthalenes, tetrathiafulvalenes and tetrathiapentalenes.

The electron ionization mass spectra of the title compounds have been studied along with the product ion spectra of their metastable or collisionally activated molecular ions. The relative abundances of ions in the spectra allow unambiguous isomer differentiation. Isomerization of the molecular ions was observed in the metastable ion spectra of tetrathianaphthalenes and tetrathiafulvalenes. This isomerization reaction parallels the electrochemical or base-induced isomerization observed in solution. The studied tetrathiapentalene derivative does not rearrange to the corresponding tetrathiafulvalene or tetrathianaphthalene isomers.

Journal Article↗

PubMed2003

Fruit juice consumption modulates antioxidative status, immune status and DNA damage.

Polyphenolic compounds exert a variety of physiological effects in vitro including antioxidative, immunomodulatory and antigenotoxic effects. In a randomized crossover study in healthy men on a low-polyphenol diet, we determined the effects of 2 polyphenol-rich juices (330 ml/d) supplemented for 2 weeks on bioavailability of polyphenols, markers of antioxidative and immune status, and reduction of DNA damage. Juices provided 236 mg (A) and 226 mg (B) polyphenols with cyanidin glycosides (A) and epigallocatechin gallate (B) as major polyphenolic ingredients. There was no accumulation of plasma polyphenols after two weeks of juice supplementation. In contrast, plasma malondialdehyde decreased with time during juice interventions. Moreover, juice consumption also increased lymphocyte proliferative responsiveness, with no difference between the two juices. Interleukin-2 secretion by activated lymphocytes and the lytic activity of natural killer cells were significantly increased by both juices. Juice intervention had no effect on single DNA strand breaks, but significantly reduced oxidative DNA damage in lymphocytes. A time-delay was observed between the intake of fruit juice and the reduction of oxidative DNA damage and the increase in interleukin-2 secretion. We conclude that consumption of either juice enhanced antioxidant status, reduced oxidative DNA damage and stimulated immune cell functions. However, fruit juice consumption for 2 weeks did not result in elevated plasma polyphenols in subjects after overnight fasting. Further studies should focus on the time-delay between juice intake and changes in measured physiological functions, as well as on active polyphenolic metabolites mediating the observed effects.

Adult↗

PubMed1987

The McGill Pain Questionnaire--German version. A study on cancer pain.

The McGill Pain Questionnaire, widely used in English-speaking countries, has been translated into German. The objective in translating the questionnaire was to produce a translation of the words while keeping the expression of the pain quality and intensity. The results of our present study with a German-speaking cancer pain population, concerning the choice of words and pain rating values, are comparable with those of similar English-speaking patients. The superiority of this multidimensional verbal questionnaire in analysis of pain qualities over unidimensional pain intensity scales was proved. The therapeutic effect of peridural opiate analgesia was measured in 30 patients with intractable cancer pain after they had completed the questionnaire. After 5 days of therapy, there was an average of 70% relief of the total pain experience, with best results obtained in patients with bone pain in the lumbo-sacral region.

Adolescent↗

PubMedDate not supplied

Dynamic force microscopy imaging of native membranes.

We employed magnetic ACmode atomic force microscopy (MACmode AFM) as a novel dynamic force microscopy method to image surfaces of biological membranes in their native environments. The lateral resolution achieved under optimized imaging conditions was in the nanometer range, even when the sample was only weakly attached to the support. Purple membranes (PM) from Halobacterium salinarum were used as a test standard for topographical imaging. The hexagonal arrangement of the bacteriorhodopsin trimers on the cytoplasmic side of PM was resolved with 1.5nm lateral accuracy, a resolution similar to images obtained in contact and tapping-mode AFM. Human rhinovirus 2 (HRV2) particles were attached to mica surfaces via nonspecific interactions. The capsid structure and 2nm sized protein loops of HRV2 were routinely obtained without any displacement of the virus. Globular and filamentous structures on living and fixed endothelial cells were observed with a resolution of 5-20nm. These examples show that MACmode AFM is a favorable method in studying the topography of soft and weakly attached biological samples with high resolution under physiological conditions.

Capsid↗