Maximum compaction of ionic organic explosives: bis(hydroxylammonium) 5,5'-dinitromethyl-3,3'-bis(1,2,4-oxadiazolate) and its derivatives.

Within this contribution on bis(oxadiazoles) we report on bis-hydroxylammonium 5,5'-dinitro-methyl-3,3'-bis(1,2,4-oxadiazolate), which (to the best of our knowledge) shows the highest density (2.00 g cm(-3) at 92 K, 1.95 g cm(-3) at RT) ever reported for an ionic CHNO explosive. Also the corresponding bis(ammonium) salt shows an outstanding density of 1.95 g cm(-3) (173 K). The reaction of the 3,3'-bis(1,2,4-oxadiazolyl)-5,5'-bis(2,2'-dinitro)-diacetic acid diethyl ester with different nitrogen-rich bases, such as ammonia, hydrazine, hydroxylamine, and triaminoguanidine causes decarboxylation followed by the formation of the corresponding salts (cation/anion stoichiometry 2:1). The reactions are performed at ambient temperature in H2O/MeOH mixtures and furnish qualitatively pure products showing characteristics of typical secondary explosives. The obtained compounds were characterized by multinuclear NMR spectroscopy, IR and Raman spectroscopy, as well as mass spectrometry. Single-crystal X-ray diffraction studies were performed and the structures of all compounds were determined at low temperatures. The thermal stability was measured by differential scanning calorimetry (DSC). The sensitivities were explored by using the BAM drophammer and friction test. The heats of formation were calculated by the atomization method based on CBS-4M enthalpies. With these values and the X-ray densities, several detonation parameters such as the detonation pressure, velocity, energy, and temperature were computed using the EXPLO5 code.

Crystal structure analysis of [Ca(O3SC18H37)2(DMSO)2], a lamellar coordination polymer and its relevance for model studies in biomineralization.

Single crystals of a one-dimensional Ca coordination polymer of the surfactant octadecyl sulfonate (C(18)H(37)SO(3)(-)) have been grown from hot DMSO solution. The X-ray structure analysis of the compound [Ca(O(3)SC(18)H(37))(2)(DMSO)(2)] (1) shows a lamellar interdigitated arrangement of hydrophobic tails of the amphiphilic ligands. Each Ca ion is coordinated by four different sulfonate groups, and its nearly octahedral coordination environment is completed by two dimethyl sulfoxide (DMSO) ligands. The octadecyl sulfonate ligand coordinates to Ca ions in a micro(2)-bridging mode, which contrasts to information from literature suggesting a micro(3)-bridging coordination mode. Since the growth of highly oriented calcite single crystals underneath Langmuir monolayers of this particular surfactant is often regarded as textbook example of a heteroepitaxy ("template") mechanism in biomineralization, we present a critical discussion of the crystal structure of the title compound in this context.

Severe superior vena cava syndrome after transvenous pacemaker implantation.

Superior vena cava syndrome is a rare complication after pacemaker implantation. The present report outlines how underestimation of clinically relevant symptoms of superior vena cava syndrome early after pacemaker implantation may result in severe complication with the need for major surgical intervention. Superior vena cava syndrome should be diagnosed early because immediate thrombolytic therapy is effective in the majority of patients and avoids the requirement for interventional or surgical efforts.

Giant aortic aneurysm 18 years after repair of double-outlet right ventricle with pulmonary stenosis.

Substantial long-term morbidity after a successful operation in complex congenital heart defects is a matter of concern. We present a patient with a giant ascending aortic aneurysm 18 years after repair of a double-outlet right ventricle with pulmonary stenosis. Our report emphasizes the need for ongoing follow-up into adulthood.

Absent long-term benefit of patch versus linear reconstruction in left ventricular aneurysm surgery.

BACKGROUND: Endoventricular patch reconstruction of the left ventricle is considered the gold standard in surgery for left ventricular aneurysms, because of improved preservation of ventricular geometry. However, the superiority over conventional linear closure has not been demonstrated, as assessed by the long-term outcome. METHODS: Two hundred patients (66%) underwent linear closure (group L) and 105 patients (34%) had endoventricular patch reconstruction (group D) using the Dor technique. Linear closure has been performed since 1974 and from 1985 on the Dor technique has been applied as an alternative procedure. Both patient groups differed regarding age, sex distribution, site of infarction, and indication for surgery. Prior to the operation, 71% of the patients were in New York Heart Association (NYHA) class III or IV and mean ejection fraction was 34% +/- 12%. Follow-up extends up to 25 years, with a cumulative total of 2,605 patient years. RESULTS: Early mortality was 6.5% in group L vs 5.7% in group D (not significant [NS]). Actuarial survival after 10 years was 56 +/- 3.2%, with no difference between groups. Freedom from reoperation after 10 years was 95.6% in group L vs 95.2% in group D (NS). Preoperative risk factors for late mortality were age, left ventricular enddiastolic volume index and concomitant mitral valve surgery. The type of procedure and the date of operation had no influence on mortality. To date, 63% of the survivors are in NYHA class I and II. CONCLUSIONS: In regard to long-term survival, rate of reoperation, and postoperative NYHA functional class, no benefit could be demonstrated when linear closure was compared with ventricular patch reconstruction for LV aneurysm repair. Hence, the technique of ventricular reconstruction may not be as important as previously thought, and at least for small aneurysms the simple and time sparing technique of linear closure may still be considered.

Long-term treatment of myasthenia gravis with immunoadsorption.

Acute treatment of myasthenic crisis with immunoadsorption (IA) or plasma exchange is well established. The efficiency of chronic apheresis therapy in myasthenia gravis (MG), however, and its efficacy in reducing concomitant potentially harmful immunosuppressive therapy, is unknown. We treated 13 patients with therapy-resistant MG or severe steroid or azathioprine therapy-related side effects, or both, with long-term IA [median, 38 (range: 16-59) months]. IA was performed every second day until partial remission was achieved (modified Osserman score <2). Subsequently, oral immunosuppressive therapy was reduced and the frequency of IA adapted to the clinical symptoms. After initiation of IA the mean (SEM) Osserman score decreased from 3.23 +/- 0.12 to 1.23 +/- 0.08 within 1 month (P < 0.01). Mean azathioprine dose was reduced concomitantly from 89 +/- 9.4 mg/day to 56 +/- 11 mg/day (P < 0.05), and mean prednisolone dose from 41 +/- 7.6 mg/day to 22 +/- 8.5 mg/day (P < 0.05). After 36 months the number of IA-sessions/month had been reduced from 4.81 +/- 0.24 to 2.64 +/- 0.4 (P < 0.05), the mean azathioprine dose to 25 +/- 17 mg/day and the mean prednisolone dose to 9 +/- 3.6 mg/day. Six out of thirteen patients were weaned from IA after a median of 33 (range, 16-50) months and a decrease of the Osserman score to 0.33 +/- 0.33. In these patients MG remained stable during a follow-up period of 28 (range, 16-38) months. We conclude that long-term IA enables the reduction of oral immunosuppressants in patients with contraindications or resistance to steroid and azathioprine therapy. Furthermore, almost 50% of the patients can be weaned from IA with then substantial lower need of further immunosuppressive therapy.

Neurotrophische Ulzerationen im Trigeminusbereich / Neurotrophic ulcerations in the trigeminal region

A patient with trigeminal trophic syndrome is presented. Neurotrophic ulcerations developed one year after injection of alcohol into the gasserian ganglion. The importance of the trigeminal trophic syndrome in the differential diagnosis to malignant skin lesions, lupus vulgaris and syphilis is discussed.