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T Schmitt

Publications and source records attributed to T Schmitt.

At least 19 recordsLinked to original sources
PubMed2006

Resonant inelastic x-ray scattering at the oxygen K resonance of NiO: nonlocal charge transfer and double-singlet excitations.

We report high-resolution polarization-dependent resonant inelastic x-ray scattering (RIXS) at the O K resonance of NiO showing a rich excitation spectrum. We perform multisite Ni6O19 cluster model calculations, revealing that solid state effects are substantial. We identify a nonlocal charge transfer excitation at 4-5 eV and double-singlet creation at 1.75 eV, both exhibiting significant scattering geometry dependence. Apart from an intense band of local charge transfer excitations (above 5 eV) also dd excitations at 1 eV are observed. Finally, we point out that O K RIXS of correlated metal oxides allows a quantitative and consistent determination of the charge transfer energy delta and the Hund coupling energy J(H).

Journal Article↗
PubMed2006

Disjunct distributions during glacial and interglacial periods in mountain butterflies: Erebia epiphron as an example.

Over several decades, the distribution patterns and evolution of alpine disjunct species has become an increasingly discussed subject. Large scale genetic analysis has allowed the resolution of the past range changes and intraspecific evolution of many species, in Europe especially of Mediterranean origin. However, the phylogeographic structures of species with arctic-alpine disjunct distribution patterns are relatively poorly studied. The existing phylogeographic analysis (mostly of alpine plant species) supports disjunct distributions during glacial as well as post-glacial periods for a number of species. However, several questions still remain unresolved and we therefore analysed the Mountain Ringlet Erebia epiphron as a model for such alpine disjunct species. We found strong differentiation into five different lineages supporting five differentiation centres: (i) the eastern Pyrenees, (ii) the mountain ranges between the central Pyrenees and south-western Alps, (iii, iv) two areas along the southern Alps margin and (v) the northern Alps margin. We propose that these patterns evolved due to the humidity requirements of this species, which did not allow survival in the dry glacial steppes, but along the margins of the wetter glaciated high mountain ranges.

Animals↗
PubMed2005

Calcium tartrate crystals in the midgut of the grape leafhopper.

Calcium tartrate crystals were observed in the midgut of grape leafhoppers. This unique compound was found for the first time in insects. The size of the crystals varied strongly between and within individuals with a mean length of 153 +/- 87 microm and a mean width of 71 +/- 46 microm. In addition, the number of crystals per individual showed a broad variation and ranged from 1 to 150 crystals/individual. The occurrence of calcium tartrate crystals as well as the number of crystals per individual followed the same seasonal pattern as seasonal vine leaf concentrations of tartaric acid found in a previous study, indicating that calcium tartrate is formed to neutralize the tartaric acid in the gut system. It further implies that the grape leafhopper, rather than being a pure phloem sucker, employs a mixed feeding strategy to satisfy its demands for calcium uptake.

Animals↗
PubMed2005

A chemical level in the coevolutionary arms race between an ant social parasite and its hosts.

Here we investigate the coevolutionary interactions between the slavemaking ant Protomognathus americanus and its Temnothorax hosts on a chemical level. We show that, although this social parasite is principally well-adapted to its hosts' cuticular hydrocarbon profile, there are pronounced differences in the fine-tuning of this adaptation. Between populations, chemical adaptation varies with host community composition, as the parasite faces a trade-off when confronted with more than one host species. In addition to adaptation of its own chemical signature, the slavemaker causes a reciprocal adjustment in its slaves' cuticular profile, the degree of which depends on the slave species. On the host side, successful parasite defence requires efficient enemy recognition, and in behavioural aggression trials, host colonies could indeed discriminate between invading slaves, which commonly accompany slavemakers on raids, and free-living conspecifics. Furthermore, hosts shifted their acceptance threshold over the seasons, presumably to reduce the costs of defence.

Adaptation, Physiological↗
PubMed2004

The genetic pattern of population threat and loss: a case study of butterflies.

Recent decreases in biodiversity in Europe are commonly thought to be due to land use and climate change. However, the genetic diversity of populations is also seen as one essential factor for their fitness. Genetic diversity in species across the continent of Europe has been recognized as being in part a consequence of ice age isolation in southern refugia and postglacial colonization northwards, and these phylogeographical patterns may themselves affect the adaptability of populations. Recent work on butterfly species with different refugia, colonization paths and genetic structures allows this idea to be examined. The 'chalk-hill blue' pattern is one of decreasing genetic diversity from south to north, whereas the 'woodland ringlet' pattern shows greater genetic diversity in eastern than in western lineages. Comparison of population demographic trends in species with these biogeographical patterns reveals higher rates of decrease with lower genetic diversity. This indicates reduced adaptability due to genetic impoverishment as a result of glacial and postglacial range changes. Analysis of phylogeographical pattern may be a useful guide to interpreting demographic trends and in conservation planning.

Animals↗
PubMed2004

Transabdominal ultrasonography in achalasia.

BACKGROUND: The aim of this study was to investigate whether transabdominal ultrasonography can differentiate between achalasia and neoplasms involving the oesophagogastric junction. METHODS: Ultrasonography was performed in 28 patients with achalasia, 28 sex- and age-matched controls and 13 patients with neoplasms. All studies were done with a 3.5 MHz real time curved array scanner and using an electronic caliper to measure oesophageal wall thickness and the maximum oesophageal diameter. Specificity and sensitivity in making a diagnosis of achalasia and tumours were determined by having unmarked images interpreted by a blinded observer. RESULTS: Patients with achalasia were identified by recognition of a dilated oesophagus without the presence of a neoplastic lesion (maximum oesophageal diameter (median)=achalasia: 20.0 (14; 25)mm; controls 10.1 (9; 11) mm; P < 0.001). Oesophageal wall thickness was similar in the two groups (achalasia: 3.2 (2.5; 3.4) mm; controls: 2.9 (2.5; 3.4)). In patients with neoplasms, a hypoechoic lesion was identified at the level of the gastric cardia. The sensitivity of making a tumour diagnosis was 100% and the specificity 82%. CONCLUSION: Transabdominal ultrasonography is a useful, non-invasive diagnostic aid in differentiating patients with primary achalasia from those with neoplastic lesions at the gastric cardia.

Abdomen↗
PubMed2003

Reduced risk for pancreatitis after endoscopic microtransducer manometry of the sphincter of Oddi: a randomized comparison with the perfusion manometry technique.

BACKGROUND AND STUDY AIMS: Endoscopic microtransducer manometry of the sphincter of Oddi has been shown to be a reliable alternative to perfusion manometry for evaluating sphincter of Oddi motor function. It avoids volume loading of the biliopancreatic system, and may therefore be associated with a lower risk of inducing postmanometry pancreatitis.[nl] PATIENTS AND METHODS: During a 2-year period, microtransducer manometry of the sphincter of Oddi was carried out in 215 patients (median age 42 years; 155 women; biliary study in 152 cases, additional pancreatic evaluation in 63 cases). Sphincter of Oddi manometry was conducted as the sole procedure in all patients. The frequency of pancreatitis was assessed prospectively and graded according to established guidelines. A total of 130 consecutive patients (median age 37 years, 92 women; 30 with biliary type II, 58 with type III, 34 with pancreatic type I, and eight with type II) were then randomly assigned to undergo microtransducer or perfusion manometry of the sphincter of Oddi in a standardized fashion. RESULTS: During the initial 2-year period, nine cases of pancreatitis (a pancreatitis frequency of 4.2 %) were observed after microtransducer manometry, and most were of mild degree (six mild, two moderate, and one severe). No deaths occurred, and no surgical procedures were required. In the randomized part of the study, the demographic and clinical characteristics of the patients in both groups, as well as the technical aspects of the procedures performed, were well matched. The frequency of pancreatitis after microtransducer manometry was 3.1 %, compared with 13.8 % after perfusion manometry ( P < 0.05). Pancreatitis occurred in two patients after microtransducer manometry, and was mild in both cases. After perfusion manometry, mild pancreatitis occurred in six patients and moderate pancreatitis in three. CONCLUSION: Endoscopic microtransducer manometry of the sphincter of Oddi is associated with a lower risk for postmanometry pancreatitis than standard perfusion manometry.

Adult↗
PubMed2003

Response to a phase II study of concomitant-to-sequential use of etoposide and radiation therapy in newly diagnosed malignant gliomas.

We evaluated the antitumor efficacy of and patient tolerance to a phase II study of concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas. Fifty-two supratentorial malignant glioma patients were enrolled in this phase II study between May 1995 and May 1998. Standard cranial irradiation and six courses of etoposide (100 mg/m2 - xdays 1-3) were administered. The first course of etoposide was given on days 1 to 3 of radiotherapy and was resumed in the week following the end of radiotherapy. Treatment was consolidated by further courses of etoposide every 4 weeks. Fifty-one patients were assessable for toxicity, response, and survival. A complete surgical resection was only noted for 17 patients. Six patients had a confirmed complete response, and eight patients displayed a partial response. Six patients progressed within the first 3 months of starting treatment. The rate of objective response for assessable patients with residual tumor was 41.1%. Hematologic toxicity was mild; grade 3 or 4 neutropenia was noted in five patients, without sepsis. The overall median survival time (MST) was 12.5 months, and the mean survival of this population was 14.9 months. These results suggest a certain efficacy of this regimen testing a concomitant-to-sequential use of etoposide and radiotherapy for newly diagnosed malignant gliomas, and that continued evaluation of this combination is warranted, especially because this treatment is also well tolerated.

Adult↗
PubMed2003

[Diagnosis of Lawsonia intracellularis using the polymerase chain reaction (PCR) in pigs with and without diarrhea and other animal species].

Lawsonia (L.) intracellularis, an obligately intracellular bacterium, causes proliferative enteropathy (PE) in swine and, occasionally, in other animals. To determine the spread of the agent among German pig herds pooled fecal samples of five animals each of clinically normal Hessian pig herds collected between november 1998 and february 1999 as well as feces (n = 1684) from individual animals representing 648 herds, sent to our laboratory by veterinarians from all parts of Germany, were tested for L. intracellularis using the polymerase chain reaction (PCR). In addition, fecal samples from diarrhoic foals (n = 46), dogs (n = 57), cats (n = 50), calves (n = 37), hedge hogs (n = 9), seals (n = 8) and one giraffe were also studied. DNA was extracted from feces using high concentrations of chaotropic salt and diatomaceous earth. For PCR, primers flanking a 279 bp fragment of L. intracellularis DNA were used (JONES, G. F., WARD, G. E., MURTAUGH, M. P., LINN, G. (1993), J. Clin. Microbiol. 31, 2611-2615). Amplificates were separated by agarose gel electrophoresis and visualized under UV-light. L. intracellularis was found in 26 (12.8%) samples from 21 (30.0%) of the Hessian pig herds without symptoms of diarrhoea. In feces of pigs with diarrhoea (n = 1684) the agent was present in 431 (25.6%) samples originating from 224 (34.6%) herds. Of the other animal species studied, L. intracellularis was detected in feces of 4 (7.0%) dogs, 2 (5.4%) calves, 3 (33.3%) hedge hogs and in the sample of the giraffe. The remaining species were all tested negative.

Animals↗
PubMed2002

Postglacial colonisation of western Central Europe by Polyommatus coridon (Poda 1761) (Lepidoptera: Lycaenidae): evidence from population genetics.

The genetic population structure of Polyommatus coridon (Poda 1761) over large regions of France, Italy and Germany was studied by allozyme electrophoresis. The genetic diversity within populations was high for all parameters analysed (number of alleles 2.72; observed and expected heterozygosity 19.6% and 20.3%, respectively; percentage of polymorphic loci: total: 76.4% and, with polymorphism if the frequency of the commonest allele is below 95%: 53.1%), whereas genetic differentiation between populations was comparatively low (FST = 0.021 +/- 0.002). The mean number of alleles declined significantly from southern to northern populations (r = -0.53, P = 0.0005). Similar effects were found also for other parameters of genetic diversity. This is interpreted as a loss of genetic diversity during postglacial expansion. However, samples from France and Italy had similar patterns of genetic diversity indicating no significant loss in this region. Populations from southern Germany were genetically uniform, well differentiated from French populations and showed a significant loss of genetic diversity. Probably, this is due to a bottleneck during passing through the Burgundian Gap, which is a migration corridor from north-eastern France to southern Germany. In contrast to southern German populations, western German populations were not well differentiated from French populations. Nevertheless, they were genetically impoverished, probably as a result from local bottlenecks and post-expansion phenomena.

Alleles↗
PubMed2002

Postglacial distribution area expansion of Polyommatus coridon (Lepidoptera: Lycaenidae) from its Ponto-Mediterranean glacial refugium.

The genetic population structure of Polyommatus coridon (Poda, 1761) (Chalk-hill blue) was studied by means of allozyme electrophoresis in north-eastern Germany, the Czech Republic, Slovakia and Hungary. All analysed parameters showed high genetic diversity within populations (number of alleles: 2.61; observed and expected heterozygosity: 18.6% and 19.7%, respectively; percentage of polymorphic loci: total: 73.6%, on 95% level: 56.1%), whereas genetic differentiation between populations was comparatively low (F(ST) = 0.028 +/- 0.005 s.d.). Hierarchical variance analysis revealed significant structuring among five regional population clusters. A significant isolation-by-distance structure exists (r = 0.39; P < 0.05). The mean number of alleles per locus declined significantly from south to north and showed a strong correlation with the geographical latitude (r = -0.88, P < 0.0001). We suggest that this reflects the loss of alleles during the postglacial colonisation of eastern Central Europe from an ice-age refugium in the Balkans. A possible scenario for the postglacial expansion process in eastern Central Europe is discussed using these data: coming from the north-western part of the Balkans, P. coridon may have reached the western tip of Hungary, and consecutively colonised eastern Central Europe using two alternative expansion routes.

Animals↗
PubMed2002

Does scant hematochezia necessitate the performance of total colonoscopy?

BACKGROUND AND STUDY AIMS: Controversy exists as to whether all patients with lower intestinal bleeding need to undergo total colonoscopy. This study compares the prevalence of colonic neoplasms in patients reporting scant hematochezia with the prevalence in controls. PATIENTS AND METHODS: Structured interviews were carried out with 4265 consecutive patients referred for colonoscopy. Of these, 468 patients had scant hematochezia, 299 had occult rectal bleeding and 57 reported dark rectal bleeding. Patients with scant hematochezia were matched for age and sex with those having no risk factors for colorectal neoplasms. For all groups, we determined the prevalence of adenomas and cancers below and above 50 cm. RESULTS: Colonic neoplasms were found in 18 % of patients with scant hematochezia and in 7.5 % of controls. However, most of these tumors were located within the reach of a sigmoidoscope. Compared with controls, patients with scant hematochezia had no increased risk for proximal neoplasms (odds ratio [OR] = 1.2), while this risk was significantly increased in patients with occult rectal bleeding (OR = 3.1) and patients who had observed maroon-colored blood in their stool (OR = 4.8). CONCLUSIONS: Flexible sigmoidoscopy appears to be a sufficient work-up for young patients who have observed trace amounts of bright red blood on the surface of their stool.

Adenoma↗
PubMed2001

Cyclandelate in the prophylaxis of migraine: a placebo-controlled study.

The prophylactic action of cyclandelate was investigated in a multicentre, randomized, placebo-controlled, parallel group study. A 4-week baseline period was followed by a 4-week placebo phase and a 16-week treatment period with either 1600 mg cyclandelate or placebo. Patients (n = 251) with two to six migraine attacks/month were randomized. Neither the primary study endpoint (reduction of migraine days from baseline to the last 28 days) nor most of the secondary endpoints (reduction in the number of migraine attacks, severity or duration of attacks, frequency of autonomic disturbances, medication for treatment of attacks) showed a difference between cyclandelate and placebo. Cyclandelate, however, was superior to placebo in a global impression of efficacy rated by the patients and the treating physicians. Both treatments were well tolerated. In conclusion, cyclandelate was not superior to placebo in the prophylaxis of migraine with regard to parameters usually used in migraine prophylaxis trials.

Adolescent↗
PubMed2001

Topical application of nitrates onto the papilla of Vater: manometric and clinical results.

BACKGROUND AND STUDY AIMS: Systemic administration of nitrates inhibits motility of the sphincter of Oddi (SO) but is hampered by a decrease of the arterial blood pressure. We evaluate whether topical application of glyceril trinitrate (GTN) onto the papilla can facilitate cannulation of the common bile duct during routine endoscopic retrograde cholangiopancreatography (ERCP) and compare the effect of topical GTN with that of isosorbide dinitrate (ISDN) on SO motility. PATIENTS AND METHODS: A total of 80 patients undergoing routine ERCP for suspected biliary obstruction received topical application of either saline (n = 40) or 10 mg of GTN (n = 40) onto the papilla of Vater in a randomized, double-blind fashion. Thereafter, selective bile-duct cannulation was attempted with a 0.035" hydrophilic guide wire. In another trial, 16 biliary type III patients underwent endoscopic SO-manometry and received in a randomized fashion either 10 mg of GTN (n = 8) or 10 mg of ISDN (n = 8) which was infused topically onto the papilla via the manometric catheter. Thereafter, the manometric recording was continued for a further 5 minutes. RESULTS: A spontaneous opening of the papilla with concurrent transpapillary bile flow was observed in 24/40 patients after topical GTN, and in only 8/40 patients after topical saline (P < 0.01). However, neither the number of cannulation attempts nor the time until successful cannulation differed significantly between the groups. In addition, the pre-cut rate was nearly identical in the two groups. Topical GTN showed no significant influence on the mean arterial blood pressure. The SO-baseline pressure was significantly lowered by topical GTN (28.2+/-12.9 mm Hg before ISDN vs. 22.5+/-13.7 mmHg after P<0.01). The phasic SO motility was also strongly inhibited by both drugs. However, the effect of GTN completely wanes after 3 minutes, whereas ISDN inhibited SO motility for > 5 minutes in all patients. CONCLUSIONS: Both topically administered GTN and ISDN evoked a profound inhibition of SO motility, but the effect of ISDN was longer lasting than that of GTN. However, locally administered GTN did not facilitate selective bile-duct access during routine ERCP.

Administration, Topical↗
PubMed2001

Transmural drainage of cystic peripancreatic lesions with a new large-channel echo endoscope.

BACKGROUND AND STUDY AIMS: The availability of a new large-channel echo endoscope led us to develop a new needle-stent device for endoscopic puncture and drainage of pancreatogenic cystic lesions. The purpose of this study was to examine whether endoscopic ultrasound (EUS)-guided one-step 10-F puncture and drainage with the new equipment could be feasible and successful. The use of the technique and the short-term outcome in our first four patients are described and discussed. PATIENTS AND METHODS: Cystic lesions were drained using the new technique in four patients. All the patients had symptomatic peripancreatic lesions, one with intrahepatic and one with intrasplenic extension. Punctures were carried out using a new echo endoscope with a 3.7 mm working channel and an Albarran lever. The 10-F transmural stents were placed over a 1 mm stainless steel needle and a 6-F Teflon catheter using a special assembly designed for controlled one-step placement and stent release. RESULTS: Puncture and drainage were technically successful in two patients. In one patient, the 10-F component failed to pass the cystic wall. Drainage was successful in the same session using a 7-F one-step device. In one patient, no stent was placed, but the 1 mm needle was used for diagnostic tissue sampling during the procedure because of the suspicious cyst morphology. Surgical resection revealed a ganglioneuroma. CONCLUSIONS: The new echo endoscope allows endoscopic interventions for peripancreatic cystic lesions under excellent endoscopic and EUS control. The Albarran lever was reliable and helpful for optimal direction of the needle. The new echo endoscope combined with special needle-stent devices was effective and safe for diagnosis and therapy in the first four cystic lesions. Cystic tumors must always be considered as a differential diagnosis in patients with apparently pancreatitis-induced cystic lesions.

Adult↗
PubMed2001

Analgesic and antiinflammatory effects of two novel kappa-opioid peptides.

BACKGROUND: This study investigates two new kappa-agonist tetrapeptides, FE 200665 and FE 200666, with high peripheral selectivity as a result of poor central nervous system penetration. METHODS: Four days after administration of Freund adjuvant into the hind paw of male Wistar rats, antinociceptive effects of intraplantar and subcutaneous injection of FE 200665 and FE 200666 were measured by paw pressure algesiometry and compared with the kappa-agonist U-69,593. Peripheral and kappa-receptor selectivity was assessed by the antagonists naloxone methiodide (NLXM) and nor-binaltorphimine, respectively. Antiinflammatory effects were evaluated by paw volume plethysmometry and histologic score. RESULTS: Similar to intraplantar U-69,593, intraplantar FE 200665 (3-100 microg) and FE 200666 (1-30 microg) resulted in significant and dose-related increases of paw pressure thresholds. Higher doses of FE 200665 (0.2-20 mg) and FE 200666 (0.06-6 mg) were required by subcutaneous route to produce similar antinociceptive responses, supporting a peripheral site of action. nor-Binaltorphimine dose-dependently antagonized this effect, implying kappa-opioid selectivity. Analgesic effects of subcutaneous FE 200665 and FE 200666 were abolished by intraplantar nor-binaltorphimine, and both subcutaneous and intraplantar effects were dose-dependently antagonized by subcutaneous NLXM, further demonstrating a peripheral site of action. One to 6 days after Freund adjuvant inoculation, single and repeated intraplantar injections of FE 200665, FE 200666, and U-69,593 significantly reduced paw volume and histologic scores. Both changes were reversed by intraplantar nor-binaltorphimine and subcutaneous NLXM. CONCLUSION: FE 200665 is a peripherally selective kappa-agonist with potent analgesic and antiinflammatory properties that may lead to improved analgesic-antiinflammatory therapy compared with centrally acting opioids or standard nonsteroidal antiinflammatory drugs.

Analgesics, Opioid↗
PubMed2001

Comparative sequence analysis reveals extensive microcolinearity in the lateral suppressor regions of the tomato, Arabidopsis, and Capsella genomes.

A 57-kb region of tomato chromosome 7 harboring five different genes was compared with the sequence of the Arabidopsis genome to search for microsynteny between the genomes of these two species. For all five genes, homologous sequences could be identified in a 30-kb region located on Arabidopsis chromosome 1. Only two inversion events distinguish the arrangement of the five genes in tomato from that in Arabidopsis. Inversions were not detected when the arrangement of the five Arabidopsis genes was compared with the arrangement in the orthologous region of Capsella, a plant closely related to Arabidopsis. These results provide evidence for microcolinearity between closely and distantly related dicotyledonous species. The degree of microcolinearity found can be exploited to localize orthologous genes in Arabidopsis and tomato in an unambiguous way.

Brassicaceae↗