In vivo spectroscopy: a novel approach for simultaneously estimating nitric oxide and hemodynamic parameters in the rat brain

Nitric oxide (NO) is a versatile molecule involved in a wide range of biological processes. Under physiological conditions, NO reacts with oxyhemoglobin (OxyHb) to form methemoglobin (MetHb) at a very high rate. Microdialysis studies have used hemoglobin solutions as a trapping method to quantify NO in vivo. The methodology described here uses the microcapillary network with endogenous OxyHb instead of microdialysis probe with exogenous OxyHb for monitoring MetHb as an indirect index of NO levels by in vivo spectroscopy using optical fibers. This new method has been validated in rat cerebral cortex by the infusion of NO or well-known drug-induced changes in NO concentration (NMDA agonists and a NO-synthase inhibitor) and by comparing results with simultaneous voltammetric recordings. Results indicate that this spectroscopy technique is able to record large increases in MetHb levels and to detect reductions of its basal levels. In addition, data show that similar changes and kinetics can be observed with both techniques. Thus, intravascular MetHb can be used as an indirect index of NO levels. It is proposed that in vivo spectroscopy may be a useful tool to gain insight into the roles of NO in hemodynamic parameters and in other physiological processes such as the regulation of the mitochondrial respiratory chain.     

Cost-effectiveness of the treatment of heart failure with ramipril: a Spanish analysis of the AIRE study

AIMS: To estimate the cost-effectiveness of adding ramipril to conventional treatment in patients with heart failure after myocardial infarction from the perspective of the Spanish National Health System. METHODS AND RESULTS: A retrospective analysis of the AIRE study was made, using previously published data from the clinical trial combined with local Spanish resource and cost data. A typical rehospitalisation for a heart failure episode would last an average of 11.6 days with an average cost of 350.80 per day. The incremental cost of ramipril per life-year gained in the baseline case was 1550.10 after 3.8 years of follow-up. Sensitivity analysis showed that the basic conclusions were robust in spite of extreme variations in the values of the key parameters of the model. CONCLUSION: The use of ramipril in addition to conventional treatment in heart failure patients after myocardial infarction is cost-effective both according to currently accepted international standards of what constitutes a cost-effective intervention and also indirectly by comparing the results with similar pharmaceutical products financed under the Spanish National Health System.     

Abnormal stimulus-response intensity functions in posttraumatic stress disorder: an electrophysiological investigation

OBJECTIVE: The purpose of this study was to explore the relationship between combat-related posttraumatic stress disorder (PTSD) and specific augmentation versus reduction patterns for the N100 and P200 components of auditory event-related potentials evoked by tones of increasing intensity. METHOD: Event-related potentials of subjects with PTSD (N=36), subjects with no psychopathology (N=20), subjects with major depression but no PTSD (N=10), and subjects with a history of chronic alcohol abuse but no PTSD (N=8) were recorded. Brain responses were evoked by a 2000-Hz tone presented in intensity blocks of 65, 72.5, 80, 87.5, and 95 dB (SPL). RESULTS: Evoked data from five PTSD subjects were of poor quality and excluded from further analyses. For all but one subject with no psychopathology and for all subjects with a history of alcohol abuse or major depression (but no PTSD), the Cz amplitude of the P200 response component showed augmentation as a nearly linear function of tone intensity. As a group, subjects with PTSD showed no such increase in P200 response magnitude. Examination of the data from individual subjects with PTSD showed that 42% exhibited augmentation patterns similar to those seen for subjects in the comparison groups. However, 58% showed evidence of P200 reduction, with the response to the loudest tone being smaller than responses to tones of intermediate intensity. CONCLUSIONS: The data suggest that there is a significant subgroup of patients with combat-related PTSD who enter into a state of protective inhibition at relatively low stimulus intensities. It is hypothesized that this is an appropriate adaptive mechanism for these subjects rather than an indication of a core neurobiological abnormality.     

Strongly enhanced field-dependent single-molecule electroluminescence

Individual, strongly electroluminescent Ag(n) molecules (n = 2 approximately 8 atoms) have been electrically written within otherwise nonemissive silver oxide films. Exhibiting characteristic single-molecule behavior, these individual room-temperature molecules exhibit extreme electroluminescence enhancements (>10(4) vs. bulk and dc excitation on a per molecule basis) when excited with specific ac frequencies. Occurring through field extraction of electrons with subsequent reinjection and radiative recombination, single-molecule electroluminescence is enhanced by a general mechanism that avoids slow bulk material response. Thus, while we detail strong electroluminescence from single, highly fluorescent Ag(n) molecules, this mechanism also yields strong ac-excited electroluminescence from similarly prepared, but otherwise nonemissive, individual Cu nanoclusters.     

Long-term outcome of congenital intestinal pseudoobstruction

We evaluated 85 children with congenital chronic intestinal pseudoobstruction (CIP) over the past 10 years. Twelve (14%) were born prematurely. One had a family history of CIP. Six had systemic diseases. Thirty-five (41%) had urinary bladder involvement. Manometric features were consistent with myopathy in 32, neuropathy in 48, and mixed disease in 5. Of 48 patients with neuropathy, 6 had urinary bladder involvement (12.5%) (P < 0.0001 vs myopathy), and 10 had malrotation (21%) (P = NS vs myopathy). Upon referral, 53 (62%) were dependent on partial or total parenteral nutrition (PN). At the time of chart review (median 25 months after evaluation), 22 patients had died, 14 of whom were on total PN, 13 of them died because of PN-related complications and 1 died of sepsis. Three others died of sepsis while on partial PN (P = 0.007 vs mortality in patients fed enterally) and five died after small bowel transplantation. In conclusion, in children with congenital CIP, the risk for prematurity is increased twofold, the majority of cases are sporadic, abnormal bladder function is more common in myopathic CIP, and complications related to parenteral nutrition are the main cause of death in children with CIP.