Bigger, better, faster: molecular shuttles with sterically non-hindering biisoquinoline chelates

In the past, a variety of mechanically interlocked systems such as catenanes and rotaxaneswere constructed on the basis of Cu(I) coordination chemistry and endocyclic 1,10-phenanthroline ligands. This review reports on the coordination chemistry of a new family of endocyclic bidentate chelators that are sterically non-hindering, namely 8,80-diaryl-substituted 3,30-biisoquinolines. These ligands allow the construction of new multi-component assemblies that are inaccessible with the previously investigated 1,10-phenanthrolines. On the one hand, the sterically non-hindering nature of the new endocyclic chelators makes three component entanglements around octahedral metal centres such as iron(II), cobalt(II) and ruthenium(II) readily possible. On the other hand, it permits the construction of copper-based molecular shuttles that exhibit shuttling kinetics that excels over those of previously investigated analogous systems with 1,10-phenanthrolines. Thus, within this class of molecular machines, a bigger chelator leads to faster molecular movement, i.e. to a better performance of the molecular machine

Control of nanospaces with molecular devices

Cavitands and capsules define nanolitre spaces for recognition, isolation and reactions of small molecules. These systems are usually self-assembled and factors such as solvent size, stoichiometry and packing factors determine what goes into the spaces. Here, we examine two switching devices to control what and when guests get in and out of these hosts: bipyridylmetal chelation and azobenzene photoisomerisation. The effects are reversible by treatment with conventional chelating agents and brief heating, respectively. Accordingly, it is possible to trigger reactions that take place within a cylindrical capsule by light, even though the reaction process is not photochemical by nature. Likewise, the presence of metals can regulate reactions without acting as direct catalysts

Autonomic neuropathy and transcutaneous oxymetry in diabetic lower extremities

Transcutaneous oxygen tension is a useful method with which to assess the functional status of skin blood flow. The reduced values observed in diabetic patients have been interpreted as a consequence of peripheral vascular disease. However, diabetic patients show lower transcutaneous oxygen tension values than control subjects with equivalent degrees of peripheral vascular disease, suggesting that additional factors are involved. Since the autonomic nervous system influences peripheral circulation, we studied the relationship between autonomic neuropathy and foot transcutaneous oxymetry in non-insulin-dependent diabetic (NIDDM) patients without peripheral vascular disease. The following age-matched patients were selected and evaluated: control subjects, C, (n = 20), NIDDM patients without autonomic neuropathy, D, (n = 16) and with autonomic neuropathy, DN, (n = 20). All diabetic patients showed lower transcutaneous oxygen tension values than control subjects, while no differences were observed between the diabetic patients with and without autonomic neuropathy. In addition the saturation index that increases in the presence of autonomic neuropathy does not correlate with foot TcPO2. In conclusion autonomic neuropathy does not influence foot TcPO2 and therefore it is unlikely that it contributes to development of foot lesions during induction of foot skin ischaemia

Autonomic neuropathy influences great toe blood pressure

OBJECTIVE - To assess the influence of autonomic neuropathy on toe blood press RESEARCH DESIGN AND METHODS - The age-matched study subjects included 20 non-insulin-dependent diabetes mellitus (NIDDM) patients with autonomic neuropathy (DN) and 10 NIDDM patients without autonomic neuropathy (D), assessed by standard cardiovascular tests and galvanic skin response, and 8 control subjects (C). None of the subjects had peripheral vascular disease (PVD) (ankle/brachial index 0.9-1.1. RESULTS - The TBP and toe/brachial index (TBI) were significantly lower in DN than in C and D (P < 0.01). The saturation index (SI), the ratio between foot venous and arterial partial pressure of oxygen (PO2), was significantly higher in DN than in C and D (P < 0.05). An inverse relationship was found between TBI and SI (r = 0.554, P = 0.001). CONCLUSIONS - The autonomic nervous system directly influences peripheral circulation. In diabetic patients without PVD, a failure of sympathetic fibers caused by autonomic neuropathy could lead to a reduction of TBP. Therefore, TBP cannot be used as an ischemic index in diabetic patients

Autonomic neuropathy and transcutaneous oximetry in diabetic lower extremities.

The oxygen delivery to the diabetic foot may be investigated with transcutaneous oximetry and by the measurement of venous blood oxygen level drawn from the foot dorsal vein

Autonomic Neuropathy Influences Great Toe Blood Pressure.

autonomic neuropathy influences great toe blood pressure without influencing the oxygen peripheral level

Manufactured shoes in the prevention of diabetic foot ulcers

OBJECTIVE - To evaluate the efficacy of manufactured shoes specially designed for diabetic patients (Podiabetes by Buratto Italy) to prevent relapses of foot ulcerations. RESEARCH DESIGN AND METHODS - A prospective multicenter randomized follow-up study of patients with previous foot ulcerations was conducted. Patients were alternatively assigned to wear either their own shoes (control group, C; n = 36) or therapeutic shoes (Podiabetes group, P; n = 33). The number of ulcer relapses was recorded during 1-year follow-up. RESULTS - Both C and P groups had similar risk factors for foot ulceration (i.e., previous foot ulceration, mean vibratory perception threshold &gt;25 mV). After 1 year the foot ulcer relapses were significantly lower in P than in C (27.7 vs. 58.3%, P = 0.009; odds ratio 0.26 [0.2-1.54]). In a multiple regression analysis, the use of therapeutic shoes was negatively associated with foot ulcer relapses (coefficient of variation = -0.315; 95% confidence interval = -0.54 to -0.08; P = 0.009). CONCLUSIONS - The use of specially designed shoes is effective in preventing relapses in diabetic patients with previous ulceration