A new palladium nanoparticle catalyst on mesoporous silica prepared from a molecular cluster precursor

A promising approach to the controlled synthesis of supported nanoparticles involves the use of molecular carbonyl clusters as precursors. Molecular metal clusters consist of a defined number of structurally ordered atoms, and active monodisperse metal particles are formed after dispersing the molecules and removing the ligands. An octanuclear palladium cluster precursor with easily displaceable ligands was used to generate palladium nanoparticles on mesoporous MCM-41. The molecular cluster precursor, [Pd8(CO)8(PMe3)7], was directly adsorbed from solution onto MCM-41, followed by gentle thermolysis which yielded small metal nanoparticles. Compared to MCM-41-based catalysts prepared from palladium salts by conventional methods, this cluster-derived palladium catalyst has shown an efficient activity for liquid-phase hydrogenation of alkenes.

Determinants of the quality of life (QoL) in patients with an implantable cardioverter/defibrillator (ICD)

OBJECTIVES

In high-risk cardiac patients the treatment of life-threatening arrhythmias with an implantable cardioverter/defibrillator (ICD) extends survival. Other important outcome criteria are treatment side effects especially the quality of life (QoL). Knowledge of the variables that influence QoL is important for therapy decisions in ICD patients.

METHODS

Ninety-three ICD patients evaluated their QoL by the SF-36 after 1-6 years of ICD implantation. The QoL was studied in relation to cardiac function (severity of heart failure, ejection fraction), treatment course (number of shocks), coping styles and psychiatric syndromes.

RESULTS

About 30% of the somatic QoL (physical role function, pain) is determined by the patients' somatization tendency, i.e. the extent to which they suffer from non-specific symptoms (sweating, weakness in the legs, nausea). The severity of heart failure had little influence on the physical QoL. The emotional QoL is primarily determined by phobic anxiety of ICD patients.

CONCLUSIONS

Psychiatric symptoms are the most important factors to determine the QoL in ICD patients. Behavioural treatment procedures of phobic anxieties and somatization could improve QoL in ICD patients.

Atypisches koronares Isch�miesyndrom mit ballonartiger passagerer Akinesie des linksventrikul�ren Apex (?apical ballooning?) ohne Nachweis einer signifikanten koronaren Makroangiopathie

We report on three patients with acute myocardial ischemia syndrome, without significant coronary artery disease, who were admitted within one year in our hospital and presenting an atypical balloon-like, reversible left ventricular apical wall motion abnormality. The reported cases showed the following similarities: 1) elderly women (age >65 years), 2) triggered by physical or emotional stress, 3) dynamic reversible ST-T segment abnormalities and 4) positive troponin I. During a one year follow-up, all patients remained asymptomatic. As compared to the usual forms of the acute coronary ischemia syndrome, this syndrome showed a unique balloon-like left ventricular (LV) wall motion abnormality at the apex, which did not correlate with the coronary supply of a major coronary vessel. The etiology and pathophysiological basis of this coronary syndrome, which has previously been described in Japan, is still not well understood.

Analysis of Mice Tumor Models Using Dynamic MRI Data and a Dedicated Software Platform*

PURPOSE

To implement a software platform (DynaVision) dedicated to analyze data from functional imaging of tumors with different mathematical approaches, and to test the software platform in pancreatic carcinoma xenografts in mice with severe combined immunodeficiency disease (SCID).

MATERIALS AND METHODS

A software program was developed for extraction and visualization of tissue perfusion parameters from dynamic contrast-enhanced images. This includes regional parameter calculation from enhancement curves, parametric images (e. g., blood flow), animation, 3D visualization, two-compartment modeling, a mode for comparing different datasets (e. g., therapy monitoring), and motion correction. We analyzed xenograft tumors from two pancreatic carcinoma cell lines (BxPC3 and ASPC1) implanted in 14 SCID mice after injection of Gd-DTPA into the tail vein. These data were correlated with histopathological findings.

RESULTS

Image analysis was completed in approximately 15 minutes per data set. The possibility of drawing and editing ROIs within the whole data set makes it easy to obtain quantitative data from the intensity-time curves. In one animal, motion artifacts reduced the image quality to a greater extent but data analysis was still possible after motion correction. Dynamic MRI of mice tumor models revealed a highly heterogeneous distribution of the contrast-enhancement curves and derived parameters, which correlated with differences in histopathology. ASPC1 tumors showed a more hypervascular type of curves with faster and higher signal enhancement rate (wash-in) and a faster signal decrease (wash-out). BXPC3 tumors showed a more hypovascular type with slower wash-in and wash-out. This correlated with the biological properties of the tumors.

CONCLUSION

With the described software, it was possible to analyze tissue perfusion parameters in small xenograft tumor models in mice. Our data correlated with histopathological data, and the qualitative and quantitative perfusion parameters could distinguish two tumor entities with different growth characteristics.

Cardiac rehabilitation in patients with implantable defibrillators

OBJECTIVE

We examined patients with implantable cardioverter defibrillators (ICD) in order to demonstrate their safe participation in a standard rehabilitation program.

DESIGN

Prospective cohort study of a consecutive series of patients after ICD implantation. Setting Inpatient rehabilitation center.

PATIENTS AND METHODS

A total of 118 patients (73.7% male, mean age 60+/-11 years) took part for 23 +/- 4 days in a standard inpatient rehabilitation program including physical activity, psychological care, heart function seminars, and resuscitation exercises with family members. The following noninvasive tests were performed: symptomlimited exercise testing, two-dimensional echocardiography, Holter monitoring, telemetric ICD interrogation, optional fluoroscopy or X-ray examination of the thorax, and (in some patients) defibrillation threshold testing.

RESULTS

Out of 118 patients 101 patients (85.6%) participated in regular ergometer training during which the initial workload of 23 +/- 11 Watts could be increased to 45 +/- 18 Watts. An individual conditioning program was assigned to 15% (n = 17) patients, thereby enabling the inclusion of all patients in the rehabilitation process. Under these conditions 12 patients (10%) experienced ICD malfunctions requiring therapy. As a consequence of all cardiac function tests, ICD reprogramming was necessary in 26 patients (22.1%).

CONCLUSION

Following ICD implantation, patients may participate in a standard rehabilitation program without serious complications and with a significant increase in physical capacity. However, ICD malfunction occurs in approximately 10% of patients. Additional tests performed by skilled medical staff and appropriate technical equipment allows the ICD program to be optimized.

18-j�hrige Patientin mit antiepileptischer Therapie und Kammerflimmern

An 18-year old female taking anti-epileptic medication was found unconscious in her bed early in the morning. After documented ventricular fibrillation and successful resuscitation, the patient was admitted to our emergency care unit. According to ECG criteria a long-QT syndrome of the subtype 2 was suspected. A few days later, however, the patient died because of hypoxic brain death. From previous hospital reports it turned out that the patient had repeatedly experienced syncopes in the past, which were interpreted as epileptic seizures. Her 17-year old sister and the female twin of her mother had both recently died from sudden cardiac death of unknown cause. An ECG screening in the family revealed six members with LQTS. A genetic analysis revealed in all of them a previously not described rearrangement mutation (888 delG insAA) in the LQT2 gene ( HERG) that was predicted to cause a protein truncation (360X) in the amino acid chain of the I(Kr)-channel subunit. This casuistic contribution exemplifies some classical aspects of LQTS (typical adrenergic trigger mechanism, classical false diagnosis "epilepsy") and demonstrates the possibility of a genotypic classification guided by phenotypic ECG characteristics. It represents an unusual case of a LQTS with a high degree of malignancy, which requires aggressive therapeutic interventions for the family survivors.

[Differentiation between vital heart muscle tissue and infarct scar using magnetocardiography]

Magnetocardiography provides touchless information about myocardial excitation propagation and repolarization. This evolving diagnostic technique has been used so far to risk-stratify patients in terms of sudden cardiac death and to detect myocardial ischemia. We evaluated its potential to assess myocardial viability in patients with coronary artery disease. Magnetocardiography was performed using a shielded prototype 49-channel LTS SQUID system. A specific algorithm was developed to calculate automatically a set of magnetocardiographic parameters. Regional myocardial viability was determined using 18F-labeled fluoro-2-deoxyglucose positron emission tomography. We found that magnetocardiography may contribute essentially to discriminate between viable myocardium and infarct scar.

Potential of gold-bound microtubules as a new ultrasound contrast agent

Contrast agents based on gas-filled microspheres share the problem of time limited opacification due to low stability of microbubbles. The aim of this study was to test if gold-bound microtubules provide backscattering that allows microtubules to be potentially useful as an ultrasound (US) contrast agent. Gold colloids were immobilized on protein microtubule walls. Latex balloons were filled with gold-bound microtubules or conventional left heart contrast agent and were ultrasonographically imaged in fundamental and harmonic modes. Feasibility of anti-beta-tubulin antibody conjugation to gold-bound microtubules was confirmed using immune fluorescence analysis. Gold particles were successfully bound to microtubules. Contrast intensities in latex balloons filled with gold-bound microtubules (141 +/- 35) were comparable to those with Levovist (180 +/- 35) and did not decrease significantly during continuous US imaging for 20 min (135 +/- 34 vs. Levovist 5.0 +/- 2.0). Anti-beta-tubulin antibodies were successfully conjugated to gold-bound microtubules. Gold-bound microtubules provide a persistent contrast effect, suggesting their use as an ultrasonic contrast agent with the feasibility of antibody conjugation.

[Optimized logistics in the prehospital management of acute stroke]

OBJECTIVE

Current management of acute stroke is characterised by an aggressive approach including specific therapy i. e. reperfusion therapy. However currently stroke patients often arrive too late in hospitals offering adequate treatment. Therefore optimized logistics play a predominant role in modern stroke management.

AIMS OF THE STUDY

1. Does teaching of EMS staff and the public result in reduced prehospital latencies 2. Will EMS personnel be able to effectively screen patients potentially suitable for thrombolysis?

METHODS

During a six week-period all EMS patients presenting with possible signs of an acute stroke were prospectively registered (period 1). Data of interest were age, mode of primary contact, prehospital latencies, mode of transportation, destination and final diagnosis. Next an algorithm was established allowing EMS personnel to transfer patients with an assumed stroke to the best suitable hospital. Teaching comprised clinical signs, indication of CT scanning, pathophysiology, specific therapeutic options (thrombolysis), and criteria to identify patients suitable for thrombolysis. In a second step the public was continuously taught about stroke symptoms and the necessity to instantly seek EMS assistance. After 12 months data were compared to baseline (period 2).

RESULTS

(period 2 vs. Period 1): Rate of patients transferred to a stroke center: 60 % vs. 54 %; rate of those transported to hospitals not offering CT scans: 17 % vs. 26 % (p < 0.05). Percentage of patients primarily contacting the EMS system: 33 % vs. 24 %. Median interval between onset of symptoms and emergency call: 54 vs. 263 minutes Median interval between the emergency call and arrival at the emergency department: 44 vs. 58 minutes (p < 0.01). Rate of patients admitted with a diagnosis other than stroke: 18 % vs. 25 % (n. s.). Median interval between onset of symptoms and hospital admission: 140 vs. 368 minutes (p < 0.001). Median age: 69 vs. 75 years (p < 0.01).

CONCLUSION

This study demonstrates the efficacy of educational efforts in reducing latencies and in screening patients potentially suitable for thrombolysis. Future efforts will comprise more intense education of a high risk subpopulation.

Transcranial ultrasound-improved thrombolysis: diagnostic vs. therapeutic ultrasound

Success of stroke treatment with rt-PA depends on rapid vessel recanalization. Enzymatic thrombolysis may be enhanced by additional transcranial application of ultrasound (US). We investigated this novel technique using a 185-kHz probe and compared it to standard diagnostic US. In vitro studies were performed in a continuous pressure tubing system. Clots were placed in a postmortem skull and treated with rt-PA together with or without transtemporal 185-kHz US insonation (2W/cm(2)) and in comparison to 1-MHz diagnostic US (0.5 W/cm(2)). Recanalization time was significantly (p < 0.01) shorter in the 185-kHz (14.1 min) and 1-MHz (17.1 min) US rt-PA treatment group compared to rt-PA treatment alone (29.3 min.). Flow rate was significantly higher (p < 0.025) and increased faster in the combined treatment group with rt-PA + 185-kHz US compared to rt-PA + 1-MHz US. We investigated the blood-brain barrier in rats after 90-min exposure time of the brain with 185-kHz US, but no damage was observed. Results suggest efficacy and safety of the 185-kHz transducer, which is superior to diagnostic US. Such a novel US probe may be able to optimize thrombolytic stroke treatment.

A diffusion-weighted MRI study of acute ischemic distal arm paresis

OBJECTIVE

To study the site of the ischemic lesion, the underlying cause, and the prognosis of acute stroke with distal arm paresis.

METHOD

The authors investigated 14 consecutive patients with acute distal arm paresis with a diagnostic stroke protocol and early MRI, including T2-weighted images, diffusion-weighted images (DWI), and perfusion-weighted images (PWI). Acute DWI lesions were shown on coregistered T2-weighted images for analysis of the exact anatomic lesion location.

RESULTS

Patients showed a uniform (7/14), radial (3/14), or ulnar (4/14) distribution of hand paresis. In all cases, DWI identified small lesions located in the motor cortex. Topographic lesion analysis, which was correlated with the clinical deficit, showed lesions centered in the hand knob area (2/14), involving the lateral (6/14), medial (4/14), or both (2/14) borders of the hand knob. PWI (calculated time-to-peak maps) did not show a mismatch between the DWI lesion and the PWI lesion. In six patients, DWI and PWI lesions were identical in size and location; no definite perfusion deficit was seen in eight patients. In agreement with PWI, no patient showed clinical worsening, and six patients recovered completely within a week. Further investigations showed a potential source of embolus in 11 cases.

CONCLUSIONS

Acute ischemic distal arm paresis is usually caused by a small cortical lesion in the motor hand cortex attributable to distal Rolandic artery obstruction without additional tissue at risk. These findings confirm the observed benign clinical course and its apparent main cause (artery-to-artery or cardiac embolism).

Is there a link between infant botulism and sudden infant death? Bacteriological results obtained in central Germany

Despite the fact that botulism was described in Germany for the first time by Kerner in 1820, the disease is almost forgotten in this country. Only about 10-20 cases of classical botulism (intoxication) are recorded every year, including 1-2 cases of clinical infant botulism. As we assumed a high incidence of botulism to be connected with cases of sudden infant death (SID), we undertook the research work presented here. From every case of unexpected infant death up to 12 months of age, standardised specimens (blood, liver and intestine) were taken at autopsy. They were tested for the presence of botulinum neurotoxin (BoNT) and/or bacterial forms of Clostridium botulinum with subsequent BoNT neutralisation tests by the international standard mouse bioassay. Age, sex, pathological findings and season were recorded. Over a 5-year period, 75 samples including 57 SID cases were tested. Free toxin was found in nine and bacterial forms were detected in six samples. Toxin neutralisation revealed the definite presence of BoNT/BoNT producing bacteria (mainly type E), whereas another 11 toxin tests were inconclusive. According to international literature, these 15 cases are to be interpreted as infant botulism.

CONCLUSION

the results show a remarkable incidence of infant botulism without any known previous medical history, partly hidden as sudden infant death. We propose to systematically search for botulism in connection with sudden infant death.

Polymorphisms in the apolipoprotein E (APOE) gene in gerontopsychiatric patients

Two recently described polymorphisms in the promoter region of the apolipoprotein E (APOE), the -491A/T and Th1/E47csT/G polymorphism, have been suggested to be associated with an increased risk for Alzheimer's disease (AD) independent from the APOE epsilon 4 carrier status. We studied the association between the APOE epsilon 4 polymorphism and the -491A/T and Th1E47csT/G polymorphisms in a sample of 118 healthy, non-demented controls and 239 consecutively recruited gerontopsychiatric patients diagnosed as: Alzheimer's disease (N = 89), age mild cognitive impairment (N = 32), memory complainers without any cognitive deficit (N = 54) and depression/other psychiatric disorders (N = 64), to test whether the investigated polymorphisms have a high enough selectivity and specificity to distinguish between the different gerontopsychiatric disorders or to differentiate AD genetically from other forms of dementia, respectively. Also a possible association with the APOE epsilon 4 polymorphism was examined. We found a statistically significant association between the APOE epsilon 4 allele and Alzheimer's disease (p = 0.0001) and age associated memory impairment (p = 0.006). Our study failed to show an association between the promoter polymorphisms -491A/T and Th1E47csT/G in the APOE gene and gerontopsychiatric disorders either alone or in relationship to the APOE epsilon 4 polymorphism. However, if we combine our results with three previous published positive reports there seems to be an association between the -491A/T polymorphism and AD, though its size is less than found in the original publication.

[Reversible phenytoin-induced extrapontine myelinolysis]

Antiepileptic drug (AED)-induced side effects still may hinder antiepileptic therapy. We describe a 38-year-old woman with complex focal seizures. Due to normal neuroradiological findings and the lack of evident pathogenetic factors, we diagnosed cryptogenic epilepsy. In response to cognitive side effects, the initial therapy with phenobarbital was replaced by phenytoin treatment only. Subsequent MRI investigation showed a hyperintense lesion in the corpus callosum without gadolinium enhancement. Responding to an increase in seizure frequency (SF), phenytoin was replaced first by lamotrigin monotherapy and then by additional valproate treatment. An MRI follow-up investigation did not show the previously described lesion of the corpus callosum, thus suggesting phenytoin-induced extrapontine myelinolysis. In the literature, vigabatrin-induced demyelinization of the corpus callosum has also been described. In patients treated with the AEDs phenytoin or vigabatrin who demonstrate increased SF, such a side effect should be taken into account and MRI investigation performed.

The identification of microorganisms by fluorescence in situ hybridisation

Fluorescence in situ hybridisation (FISH) with rRNA-targeted oligonucleotide probes facilitates the rapid and specific identification of individual microbial cells in their natural environments. Over the past year there have been a number of methodological developments in this area and new applications of FISH in microbial ecology and biotechnology have been reported.

Potential use of therapeutic ultrasound in ischemic stroke treatment

Systemic treatment with rtPA approved for a 3-hour window is the only established causal therapy for acute stroke in the United States and Canada. Thrombolytic therapy with rtPA demonstrated a small, although significantly reduced morbidity, in a limited number of highly selected patients. As recently shown, intraarterial application is favorable and opens the window of treatment up to 6 hours. The combination of ultrasound with thrombolytic agents may further enhance the potential benefit by means of enzymatic-mediated thrombolysis, which has been demonstrated in different in vitro and in vivo experiments for an accelerated recanalization of occluded peripheral and coronary vessels. Whereas no or only small attenuation of ultrasound can be expected through skin and chest, intensity will be significantly attenuated if penetration of the skull is required. The transcranial penetration of ultrasound increases when the frequency is decreased to 20 kHz and may be transmitted through the skull transtemporally with tolerable attenuation up to 200 kHz. This results in efficacy in vitro with low intensities of 0.5-2.0 W/cm(2) systemic treatment with rtPA approved for a 3-hour window in the nonfocused ultrasound field. Application of ultrasound insonation increased rtPA-mediated thrombolysis up to 20% in a static model; meanwhile, it enhanced the recanalization rate from 30%-90% in a flow model. In vitro results suggest that 1 MHz ultrasound with 0.5 W/cm(2), established for diagnostic purposes, may already enhance rtPA- mediated thrombolysis. Before therapeutic ultrasound can be tested clinically in acute stroke, safety of transcranial exposure of the brain has to be confirmed. To date, animal experiments suggested no harm to the blood brain barrier or systemic heating with 2 W/cm(2). This combined treatment is one perspective in optimizing therapy in acute stroke within the acute phase and may be applied easily with few limitations.