A Novel Matrix-Array-Based MR-Conditional Ultrasound System for Local Hyperthermia of Small Animals.

OBJECTIVE: The goal of this work was to develop a novel modular focused ultrasound hyperthermia (FUS-HT) system for preclinical applications with the following characteristics: MR-compatible, compact probe for integration into a PET/MR small animal scanner, 3D-beam steering capabilities, high resolution focusing for generation of spatially confined FUS-HT effects. METHODS: For 3D-beam steering capabilities, a matrix array approach with 11 × 11 elements was chosen. For reaching the required level of integration, the array was mounted with a conductive backing directly on the interconnection PCB. The array is driven by a modified version of our 128 channel ultrasound research platform DiPhAS. The system was characterized using sound field measurements and validated using tissue-mimicking phantoms. Preliminary MR-compatibility tests were performed using a 7T Bruker MRI scanner. RESULTS: Four 11 × 11 arrays between 0.5 and 2 MHz were developed and characterized with respect to sound field properties and HT generation. Focus sizes between 1 and 4 mm were reached depending on depth and frequency. We showed heating by 4 °C within 60 s in phantoms. The integration concept allows a probe thickness of less than 12 mm. CONCLUSION: We demonstrated FUS-HT capabilities of our modular system based on matrix arrays and a 128 channel electronics system within a 3D-steering range of up to ±30°. The suitability for integration into a small animal MR could be demonstrated in basic MR-compatibility tests. SIGNIFICANCE: The developed system presents a new generation of FUS-HT for preclinical and translational work providing safe, reversible, localized, and controlled HT.

Living phosphatic stromatolites in a low-phosphorus environment: Implications for the use of phosphorus as a proxy for phosphate levels in paleo-systems.

In the geological record, fossil phosphatic stromatolites date back to the Great Oxidation Event in the Paleoproterozoic, but living phosphatic stromatolites have not been described previously. Here, we report on cyanobacterial stromatolites in a supratidal freshwater environment at Cape Recife, South African southern coast, precipitating Ca carbonate alternating with episodes of Ca phosphate deposition. In their structure and composition, the living stromatolites from Cape Recife closely resemble their fossilized analogues, showing phosphatic zonation, microbial casts, tunnel structures and phosphatic crusts of biogenic origin. The microbial communities appear to be also similar to those proposed to have formed fossil phosphatic stromatolites. Phosphatic domains in the material from Cape Recife are spatially and texturally associated with carbonate precipitates, but form distinct entities separated by sharp boundaries. Electron Probe Micro-Analysis shows that Ca/P ratios and the overall chemical compositions of phosphatic precipitates are in the range of octacalcium phosphate, amorphous tricalcium phosphate and apatite. The coincidence in time of the emergence of phosphatic stromatolites in the fossil record with a major episode of atmospheric oxidation led to the assumption that at times of increased oxygen release the underlying increased biological production may have been linked to elevated phosphorus availability. The stromatolites at Cape Recife, however, form in an environment where ambient phosphorus concentrations do not exceed 0.28 µM, one to two orders of magnitude below the previously predicted minimum threshold of >5 µM for biogenic phosphate precipitation in paleo-systems. Accordingly, we contest the previously proposed suitability of phosphatic stromatolites as a proxy for high ambient phosphate concentrations in supratidal to shallow ocean settings in earth history.

[Pulmonary nocardiosis with trimethoprime/sulphamethoxazole-resistant Nocardia paucivorans in a patient with no signs of immunosuppression]. / Pulmonale Nokardiose mit Trimethoprim/Sulfamethoxazol resistenter Nocardia paucivorans bei einem Patienten ohne Hinweise auf Immunsuppression.

This is so far the first published case report of a Nocardia paucivorans infection in an immunocompetent patient. A 54-year-old farmer was hospitalised with a history of coughing and fever for a period of five months. There was no indicator of either primary of secondary immunodeficiency in the prior medical history. A chest X-ray showed pneumonic infiltrates in the right middle und lower lobes, which progressed despite of antibiotic therapy with macrolides. A transbronchial biopsy revealed unspecific granulomatous inflammation of soft tissues. N. paucivorans - grew in cultures of sputum, bronchoalveolar lavage, and transbronchial biopsy. Oral antibiotic therapy was started with trimethoprime-sulphamethoxazole (TMP/SMX) and amoxicillin plus clavulanic acid. Susceptibility testing revealed high level resistance to TMP/SMX, which was consequently replaced by ciprofloxacin. Six months later, infiltrates had completely resolved and the patient did not report any residual clinical symptoms. The present case showed once again that nocardiosis is not limited to patients with immunodeficiencies. However, conservative combination therapy with oral antibiotics seems to be sufficiently effective for nocardiosis in the immunocompetent patient. For cases of suspected nocardiosis, a step-wise, risk-based diagnostic and therapeutic procedure is proposed.

Changes in plasma norepinephrine concentration and thrombocyte alpha 2-adrenoceptor density during long-term antihypertensive therapy with nitrendipine and captopril.

Antihypertensive drugs influence the sympathetic nervous system in different ways that may cause adverse or beneficial effects. We treated 48 hypertensive patients with either nitrendipine (10-20 mg twice daily, b.i.d.) or captopril (25-50 mg b.i.d.) for 16 weeks to evaluate changes in plasma catecholamines, platelet alpha 2- and lymphocyte beta 2-adrenoceptors. Blood pressure (BP) decreased from 153/95 to 135/87 mm Hg with captopril and from 155/99 to 137/89 mm Hg with nitrendipine. Treatment with nitrendipine significantly stimulated plasma norepinephrine (NE) from 327 +/- 37 to 446 +/- 50 pg/ml, and treatment with captopril resulted in a significant reduction in platelet alpha 2-adrenoceptor density from 265 +/- 39 to 171 +/- 26 fmol/mg protein. Despite having equal BP-lowering properties, captopril and nitrendipine have different effects on the sympathetic nervous system. Stimulation of plasma NE during long-term treatment with nitrendipine may contribute to possible adverse effects, whereas reduction in alpha 2-adrenoceptors induced by captopril may contribute to the vasodilating effect of angiotensin-converting enzyme (ACE) inhibition.

Effect of short-term antihypertensive therapy on left ventricular wall tension. A double-blind comparison of isradipine and nifedipine.

The comparative efficacy of the calcium antagonists isradipine and nifedipine in reducing left ventricular peak systolic wall tension was assessed in 25 patients with essential hypertension (20 men, 5 women; mean age: 49 years). After 2 weeks of treatment with either isradipine (2.5 mg twice daily) or slow-release nifedipine (20 mg twice daily), blood pressure was similarly reduced in both groups of patients whereas the thickness of the interventricular septum and left ventricular free wall did not change. Echocardiographic end-diastolic volume of the left ventricle showed no change whereas end-systolic volume significantly decreased with isradipine, but not with nifedipine retard. This led to a significant reduction in peak systolic wall tension in the isradipine group, but not in the nifedipine group. In conclusion, antihypertensive treatment with isradipine produces a reduction in peak systolic wall tension which is not seen with nifedipine, probably because of its negative inotropic effect.

[Psychological consulting of children awaiting leg amputation (author's transl)]. / Psychologische Vorbereitung auf körperverändernde Operationen im Kindesalter. Vorbereitung zweier Geschwister auf ihre Unterschenkelamputation

A 2.3 year old boy and a 3.7 year old girl, brother and sister, burnt their feet and calves during a bath tub accident. Both had to undergo amputation of their feet and lower thirds of their calves. For this, both needed psychological help. The body was less anxious and ready for confrontation with reality. The girl had to be guided through her denial and rejection of reality towards acceptance of the situation. Only then was she able to express fear and accept help. This practical playtherapeutical intervention could only take place on the basis of absolute trust. Time, empathy, adaptation to the children's state, age and personality and repetetive, active playing of the situation and the anxiety provoking future were necessary. Thus panic provoking anxiety could be diminished to realistic fear.