Nature of the observed ν(NO) band shift and splitting during the 3D to 2D structural change in transition metal nitroprussides

The electronic structure and related optical properties of the nitroprusside ion, [Fe(CN)₅NO]^2-, are dominated by the nitrosyl (NO⁺) group. The light-induced 2b₂(xy) → 7e(π*NO) (Fe → NO) and related appearance of meta-stable isomers for the NO group supports many of the functional properties of metal nitroprussides. In recent studies on the preparation of 2D transition metal nitroprussides from their 3D analogs, we have observed that such a structural change is concomitant with a decrease for the ν(NO) frequency and certain band splitting (unfolding). The 3D to 2D structural modification leads to an increase in the electron density at the iron atom. This results in an enhancement for the π*-back donation, which increases the electron population at the π*_2px and π*_2py orbitals. These last orbitals are doubly degenerated, and the increase for the π*-back bonding induces the removal of that degeneration via the Jahn-Teller effect. This intuitive mechanism explains the mentioned band unfolding related to the structural change. Such explanation was herein supported by a model based on the normal modes for the FeNO fragment derived from the small oscillation formalism around the equilibrium positions for the involved atoms. This model shows that there is a very close relationship between the deformation of the nitrosyl group (NO⁺) and the splitting of the IR bands. That is, the less linear the nitrosyl group, the greater the shift and splitting of the mentioned IR band. An excellent coincidence between the frequency values calculated using the model and the experimental ones was observed. The largest difference between the theoretically calculated ν(NO) frequencies and the experimental ones was only 6 cm^-1 and 5 cm^-1 in representative samples of 2D and 3D transition metal nitroprussides, respectively. The understanding of such an effect could be relevant for the functional properties of these 2D coordination polymers.

Thermally induced spin crossover in Fe(PyrDer)2[Fe(CN)5NO] with PyrDer = 4-substituted pyridine derivatives

From the intercalation of 4-substituted pyridine derivatives in 2D ferrous nitroprusside, a series of hybrid inorganic–organic solids with thermally induced spin crossover results.

The anti-CD6 antibody itolizumab provides clinical benefit without lymphopenia in rheumatoid arthritis patients: results from a 6-month, open-label Phase I clinical trial

Itolizumab is a humanized anti-CD6 monoclonal antibody (mAb) that has previously shown encouraging results, in terms of safety and positive clinical effects, in a 6-week monotherapy clinical trial conducted in rheumatoid arthritis (RA) patients. The current Phase I study evaluated the safety and clinical response for a longer treatment of 12 itolizumab intravenous doses in subjects with active RA despite previous disease-modifying anti-rheumatic drug (DMARD) therapy. Twenty-one subjects were enrolled into four dosage groups (0·1, 0·2, 0·4 and 0·8 mg/kg). Efficacy end-points including American College of Rheumatology (ACR)20, ACR50 and ACR70 response rates and disease activity score in 28 joints (DAS28) were monitored at baseline and at specific time-points during a 10-week follow-up period. Itolizumab was well tolerated up to the highest tested dose. No related serious adverse events were reported and most adverse events were mild. Remarkably, itolizumab treatment did not produce lymphopenia and, therefore, was not associated with infections. All patients achieved a clinical response (ACR20) at least once during the study. Eleven subjects (55%) achieved at least a 20% improvement in ACR just 1 week after the first itolizumab administration. The clinical response was observed from the beginning of the treatment and was sustained during 24 weeks. The efficacy profile of this 12-week treatment was similar to that of the previous study (6-week treatment). These results reinforce the safety profile of itolizumab and provide further evidence on the clinical benefit from the use of this anti-CD6 mAb in RA patients.

QEEG prognostic value in acute stroke

The objective of our study is to determine the predictive value of QEEG in patients suffering from an acute ischemic cerebral stroke. Twenty-eight patients were studied within the first 72 hours of clinical evolution of middle cerebral artery territory ischemic stroke. Thirty-seven QEEG recordings were obtained: 13 in the first 24 hours after cerebral stroke onset, 9 between 24-48 hours and 15 between 48-72 hours. Absolute Energies (AE) were the QEEG selected variables for statistical analysis: first, AE Z values were calculated using the Cuban QEEG norms, then the maximum and minimum AE Z values were selected within each frequency band and total power. The medians of the five neighboring Z values were also chosen. Regression models were estimated using the RANKIN scores as dependent variables and the selected QEEG variables as independent, then outcome predictions at hospital discharge and 3 months later were calculated. Percentages of concordance and errors between the estimated and real outcome scores were obtained. Alpha and theta AE were the best predictor for short-term outcome and delta AE for long-term outcome. We conclude that QEEG performed within the first 72 hours of ischemic stroke might be a powerful tool predicting short- and long-term outcome.

Predicting outcome in acute stroke: a comparison between QEEG and the Canadian Neurological Scale

OBJECTIVE

To determine and compare the predictive value of quantitative EEG (QEEG) and the Canadian Neurological Scale (CaNS), in patients with an acute cerebral stroke.

METHODOLOGY

Twenty-eight patients were studied with the diagnosis of acute ischemic middle cerebral artery stroke, within the first 72 hours of clinical evolution. Thirty-seven EEGs and clinical evaluations were collected: 13 during the first 24 hours after stroke onset, 9 between 24-48 hours and 15 between 48-72 hours. The QEEG studied variables were: the Z values (maximum, minimum and the Z medians from the 5 nearest points to each one) of absolute energies (AE) from the 4 classic frequencies bands. The clinical scale showed a smaller percent of correct prognosis than QEEG variables.

CONCLUSIONS

QEEG was demonstrated to be a powerful tool to predict the degree of residual functional disabilities after an acute ischemic stroke and showed a higher prognostic value than CaNS when they are performed within the first 72 hours of brain infarct.