Coordination chemistry of nitrile-functionalized mixed thia-aza macrocycles [9]aneN2S and [9]aneNS2 towards silver(I)

The aim of this study is to determine how far the length and number of the pendant arms in nitrile-functionalized derivatives of small mixed-donor macrocycles influence the structure of silver(I) com­plexes, both in the presence and absence of exogenous ligands.

The coordination chemistry towards silver(I) of the small-ring macrocycles [9]aneN₂S (1-thia-4,7-di­aza­cyclo­nona­ne) and [9]aneNS₂ (1,4-di­thia-7-aza­cyclo­nona­ne) incorporating nitrile-functionalized pendant arms is considered both in the presence and the absence of exogenous bridging ligands. The aim is to understand the influence of the number and length of the pendant arms on the nuclearity and dimensionality of the resulting com­plexes. The X-ray crystal structures of the com­plexes bis­[4,7-bis­(cyano­meth­yl)-1-thia-4,7-di­aza­cyclo­non­ane-κ³N,N′,S]silver(I) tetra­fluorido­borate, [Ag(C₁₀H₁₆N₄S)₂]BF₄ or [Ag(L¹)₂]BF₄, [4,7-bis­(2-cyano­eth­yl)-1-thia-4,7-di­aza­cyclo­nonane-κ³N,N′,S](thio­cyanato-κS)silver(I), [Ag(C₁₂H₂₀N₄S)(NCS)] or [Ag(L²)(SCN)], and μ-thio­cyanato-κ²S:S-bis­{[7-(2-cyano­eth­yl)-1,4-di­thia-7-aza­cyclo­nonane-κ³N,S,S′]silver(I)} tetra­fluor­ido­borate, [Ag₂(C₉H₁₆N₂S₂)₂(SCN)]BF₄ or [Ag₂(L³)₂(μ-SCN)]BF₄, are discus­sed in relation to analogous com­pounds in the literature.

Post-synthetic modulation of the charge distribution in a metal-organic framework for optimal binding of carbon dioxide and sulfur dioxide

Modulation of pore environment is an effective strategy to optimize guest binding in porous materials. We report the post-synthetic modification of the charge distribution in a charged metal-organic framework, MFM-305-CH₃, [Al(OH)(L)]Cl, [(H₂L)Cl = 3,5-dicarboxy-1-methylpyridinium chloride] and its effect on guest binding. MFM-305-CH₃ shows a distribution of cationic (methylpyridinium) and anionic (chloride) centers and can be modified to release free pyridyl N-centres by thermal demethylation of the 1-methylpyridinium moiety to give the neutral isostructural MFM-305. This leads simultaneously to enhanced adsorption capacities and selectivities (two parameters that often change in opposite directions) for CO₂ and SO₂ in MFM-305. The host-guest binding has been comprehensively investigated by in situ synchrotron X-ray and neutron powder diffraction, inelastic neutron scattering, synchrotron infrared and ²H NMR spectroscopy and theoretical modelling to reveal the binding domains of CO₂ and SO₂ in these materials. CO₂ and SO₂ binding in MFM-305-CH₃ is shown to occur via hydrogen bonding to the methyl and aromatic-CH groups, with a long range interaction to chloride for CO₂. In MFM-305 the hydroxyl, pyridyl and aromatic C-H groups bind CO₂ and SO₂ more effectively via hydrogen bonds and dipole interactions. Post-synthetic modification via dealkylation of the as-synthesised metal-organic framework is a powerful route to the synthesis of materials incorporating active polar groups that cannot be prepared directly.

Induction chemotherapy in primary resectable head and neck tumors - a prospective randomized trial

Although induction chemotherapy prior to local therapy produces encouraging initial response rates in head and neck cancer, randomized studies have failed to demonstrate an advantage in survival. All randomized studies included only patients with far advanced stage III and IV disease which appears to be the main reason for the low rate of complete responses (max. 18%) in these trials. According to statistical considerations nearly 50% complete responders are necessary before improved survival benefit can be expected. Until now, such complete response rates are only achieved with induction chemotherapy in resectable T2-T3, N0-N2 disease. Therefore, we started a prospective randomized trial including only patients with these stages of disease. Patients were stratified by primary tumor site and neck node status and were randomized to receive either induction chemotherapy with three cycles of carboplatin/5-FU prior to surgery and radiotherapy (arm A, 49 patients) or standard treatment with surgery and radiotherapy (arm B, 47 patients). Patients were stratified by primary tumor site and neck disease. After a follow-up of 12-48 months overall survival was 72% in arm A and 53% in arm B (n.s.). Considering only the patients with cancer of the oral cavity and the tonsil overall survival was 88% in arm A and 44% in arm B (p<0.05). As of today, the number of patients with carcinomas of the hypopharynx and base of tongue is too small for a statistically significant statement, but preliminary data indicate a better overall and disease-free survival without chemotherapy in these patients. Therefore, we recommend controlled trials with induction chemotherapy in patients with primary resectable carcinomas of the oral cavity and the tonsil, stages T2-T3 and N0-N2, prior to surgery but not in patients with cancer of the hypopharynx and base of the tongue.

A hybrid approach for quantification of aortic valve stenosis using cardiac magnetic resonance imaging and echocardiography:

We replaced Doppler-derived stroke volume in the continuity equation (method A) by either right heart catheterization-derived stroke volume (method B) or cardiovascular magnetic resonance-derived stroke volume (method C) to calculate aortic valve area in 20 consecutive patients with moderate or severe aortic stenosis. Comparison of both hybrid methods (methods B and C) by Bland-Altman analysis showed a mean difference near zero, a spread within two standard deviations and very similar limits of agreement. More importantly, all patients were classified into the same category of severity by both methods.

Relative bioavailability and plasma paracetamol profiles of Panadol suppositories in children

OBJECTIVE

To determine the relative bioavailability and plasma paracetamol concentration profiles following administration of a proprietary formulation of paracetamol suppositories to postoperative children.

METHODOLOGY AND RESULTS

Study A-eight children undergoing minor surgery had blood samples collected following the rectal administration of either a 250 mg or 500 mg paracetamol suppository on one day and an equivalent oral dose on the following day. A mean dose of 13 mg/kg gave a mean Cmax (Tmax) of 7.7 mg/L (1.6 h) and 4.9 mg/L (2.0 h) following oral and rectal administration, respectively. The mean relative rectal bioavailability was 78% (95% confidence interval of 55-101%). Study B-20 children undergoing tonsillectomy and/or adenoidectomy were randomly assigned to receive a postoperative dose of 500 mg of paracetamol either as 2 x 250 mg liquid filled or 1 x 500 mg hard wax Panadol suppository. A mean dose of 25 mg/kg produced mean maximum plasma paracetamol concentrations of 13.2 mg/L and 14.5 mg/L at 2.1 and 1.9 h for the hard and liquid filled suppository, respectively. The absorption rate constants and areas under the curves suggested no difference in the rate or extent of absorption between the two formulations.

CONCLUSION

Absorption of paracetamol following rectal administration of Panadol suppositories to postoperative children is slower and reduced as compared to oral therapy. The hard wax and liquid filled products have similar absorption characteristics. The usually quoted antipyretic therapeutic range for paracetamol is 10-20 mg/L, although 5 mg/L may be effective. A single rectal dose of 25 mg/kg will obtain this lower concentration within 1 h of administration and maintain it for up to 6 h. When given in an appropriate dose for analgesia, maximum plasma paracetamol concentrations would be available in the immediate postoperative period if the rectal dose was given 2 h before the planned end of the procedure.

Development of a regional cohort of very-low-birthweight children at six years: cognitive abilities are associated with neurological disability and social background

The authors studied the intelligence, memory, visuomotor skills and la nguage of 298 six-year-old children with very low birthweight (VLBW) (less that 1500g). Of 591 VLBW childern born July 1983 to June 1986 within 50km of the centre of Hamburg, Germany, 330 were traceable at age six years and 298 of these were seen by a neuropaediatrician and a psychologist; the other 19 were too severely disabled for psychological assessment with the standardized tests used. The mean memory performance of VLBW children at age six years was below the standard mean in all diagnostic and socio-economic subgroups. As expected, visuomotor development was clearly influenced by neurological but not socio-economic status. Intelligence and language skills were much more closely related to socio-economic background that to neurological morbidity. However, VLBW children with hyperactivity, clumsiness or cerebral palsy differed significantly in intelligence and visuomotor performance from those without neurological symptoms.

Botulinum toxin in the therapy of gustatory sweating

Three patients suffering from gustatory sweating following trauma to the preauricular region from a bullet wound or parotid gland surgery were treated by intracutaneous injection of botulinum toxin A. Within 2 weeks, gustatory sweating in the area injected completely ceased in all patients with no side-effects. The efficacy of treatment was confirmed by repeated Minor's iodine starch tests. So far, sweating has not recurred during a follow-up period of up to 8 months. Botulinum toxin appears to be a promising new drug for the treatment of this autonomic disorder.

Arthroscopically assisted arthrodesis of the ankle joint

In 26 patients we performed an arthroscopically assisted arthrodesis of the ankle. The patients' ages ranged from 31 to 69 years. The male:female ratio. Sixteen patients had posttraumatic degenerative joint disease, three patients suffered from a previous infection, four patients had rheumatoid arthritis, and three patients had an osteochondritis dissecans in their past history. The time taken for surgery ranged from 65 to 135 min. Compared with open procedures we documented less postoperative swelling and minor use of analgesics. Time of follow-up was a minimum of 6 months and a maximum of 75 months. In 22 patients we found solid fusion at the time of followup. Fusion was accomplished by 2 months postoperatively in four patients, by 3 months in nine patients, by 4 months in another six patients, and by 6 months in 3 patients. Three patients did not evidence any bony fusion, but they were free of pain. In one patient an open revision was necessary. According to our experience, we recommend arthroscopically assisted arthrodesis of the ankle in patients with degenerative joint disease without rotational or varus/valgus malalignment, severe bone defects or neuropathic disease.

Clinical symptoms caused by intra-articular fibrous plicae after knee replacement. Arthroscopic diagnosis and therapy

In 29 patients with persistent complaints after knee replacement we found intra-articular fibrous tissue in different areas of the joint. In 26 patients diagnostic arthroscopy was followed by arthroscopic resection of the tissue. The fibrous tissue was differentiated into five types. Type 1 represented a transverse fibrous band located at the superior margin of the femoral component of the prosthesis. A type 2 plica was a lateral plica extending from the superolateral border of the patella to the infrapatellar fat pad. The type 3 fibrous band reached from the inferior pole of the patella to the intercondylar area. The type 4 nodulus was located at the superior border of the patella, and the type 5 plica was a meniscoid-like tissue between the femoral and the tibial component. Arthroscopic resection resolved the symptoms in 25 of the patients. Different factors seem to contribute to the development of intra-articular plicae after knee alloarthroplasty.