Batching of low-concentration anesthetics with evaporators used in apparatuses for inhalation anesthesia

The accuracy of the anesthetic vaporizers with modern vaporizing devices is complicated by necessity of providing small anesthetic vapor concentration for a wide range of gas flows, especially at small flows, and at use of a combination of inhalation anesthesia with intravenous one. Compliance with the requirements of the international standards concerning the accuracy of low-concentration anesthetic vapor batching also does not provide management of anesthesia depth at various stages of surgical operations. The problem is solved well by replacement traditional vaporizers with so-called barbotage ones equipped by adjustment of vapor concentration by modem electronic methods. It is even more promising to use direct injection of the liquid anesthetics into the respiratory contour of infusion pump. However, because individual sensitivity of patients to anesthetics is rather variable, these devices do not provide regulation of the depth of anesthesia. Therefore, stability rather than accuracy of batching of low-concentration anesthetics with evaporators used in apparatuses for inhalation anesthesia is of cardinal importance, Methods of objective instrumental evaluation of the depth of anesthesia require further research and implementation.     

Dynamics of corrected QT interval and heart rate in patients with early postinfarction angina

The subjects of the study were 135 patients with acute Q-wave and non-Q-wave myocardial infarction (MI) aged 36 to 78 years (mean 62.4 +/- 11.2 years). 59 patients (main group) developed early postinfarction angina (EPA). 76 patients (control group) had no stenocardia attacks within the entire period of hospital treatment. In the patients with EPA corrected QT interval dispersion was greater within the entire period of hospital treatment: 81.2 +/- 7.6 and 67.1 +/- 4.6 ms1/2 on the first day, 74.6 +/- 6.0 and 70.3 +/- 4.7 ms1/2 on the third day, 82.1 +/- 6.5 and 71.6 +/- 6.2 ms1/2 on the seventh day, 88.7 +/- 6.2 and 69.4 +/- 8.2 ms1/2 on the 28th day, respectively. Heart rate entropy decreased in both groups, but before discharge (mean 28th day) the patients with EPA demonstrated its significant reduction compared to the patients without EPA (3.89 +/- 0.16 and 4.13 +/- 0.09 bits, respectively, p < 0.05). Thus, recurrent myocardial ischemia in patients with MI, manifesting by EPA attacks, leads to the increase of QT interval dispersion and to heart rate rigidity which apparently mirrors greater probability of myocardial electric instability and increased risk of fatal arrhythmias in such patients.     

Method of recording contractions of isolated blood vessels with the aid of a photoresistor

An apparatus for recording the tone and contractions of isolated vessels of various animals is described. The principle of the method consists of recording changes in the volume of an isolated vessel filled with Ringer-Locke solution by means of a photoresistor.     

Optimal design of structured nanospheres for ultrasharp light-scattering resonances as molecular imaging multilabels

Optical molecular imaging could potentially enable noninvasive high-resolution characterization and diagnosis of living tissue. The capability to image multiple molecular targets simultaneously is particularly important. Currently this task cannot be achieved using conventional optical contrast agents, due to their broad spectral responses (approximately 80 to 200 nm). Developments in research on semiconductor nanocrystals (quantum dots) provide one possible solution. We describe a different concept of multilabel molecular imaging that utilizes resonant light-scattering spectroscopy of multilayered nanospheres to achieve tunable ultrasharp resonance peaks with widths as narrow as 10 nm. Our theoretical study demonstrates that dozens of molecular targets can potentially be imaged simultaneously using this approach.     

Multiple projection optical diffusion tomography with plane wave illumination

We describe a new data collection scheme for optical diffusion tomography in which plane wave illumination is combined with multiple projections in the slab imaging geometry. Multiple projection measurements are performed by rotating the slab around the sample. The advantage of the proposed method is that the measured data are more compatible with the dynamic range of most commonly used detectors. At the same time, multiple projections improve image quality by mutually interchanging the depth and transverse directions, and the scanned (detection) and integrated (illumination) surfaces. Inversion methods are derived for image reconstructions with extremely large data sets. Numerical simulations are performed for fixed and rotated slabs.     

Variability in apoptotic response to poliovirus infection

In several cell types, poliovirus activates the apoptotic program, implementation of which is suppressed by viral antiapoptotic functions. In such cells, productive infection leads to a necrotic cytopathic effect (CPE), while abortive reproduction, associated with inadequate viral antiapoptotic functions, results in apoptosis. Here, we describe two other types of cell response to poliovirus infection. Murine L20B cells expressing human poliovirus receptor responded to the infection by both CPE and apoptosis concurrently. Interruption of productive infection decreased rather than increased the proportion of apoptotic cells. Productive infection was accompanied by the early efflux of cytochrome c from the mitochondria in a proportion of cells and by activation of DEVD-specific caspases. Inactivation of caspase-9 resulted in a marked, but incomplete, prevention of the apoptotic response of these cells to viral infection. Thus, the poliovirus-triggered apoptotic program in L20B cells was not completely suppressed by the viral antiapoptotic functions. In contrast, human rhabdomyosarcoma RD cells did not develop appreciable apoptosis during productive or abortive infection, exhibiting inefficient efflux of cytochrome c from mitochondria and no marked activation of DEVD-specific caspases. The cells were also refractory to several nonviral apoptosis inducers. Nevertheless, typical caspase-dependent signs of apoptosis in a proportion of RD cells were observed after cessation of viral reproduction. Such "late" apoptosis was also observed in productively infected HeLa cells. In addition, a tiny proportion of all studied cells were TUNEL positive even in the presence of a caspase inhibitor. Degradation of DNA in such cells appeared to be a postmortem phenomenon. Biological relevance of variable host responses to viral infection is discussed.     

Spontaneous development of bilateral subdural hematomas in an infant with benign infantile hydrocephalus: color Doppler assessment of vessels traversing extra-axial spaces

We present an infant with macrocrania, who initially demonstrated prominent extra-axial fluid collections on sonography of the brain, compatible with benign infantile hydrocephalus (BIH). Because of increasing macrocrania, a follow-up sonogram of the brain was performed; it revealed progressive enlargement of the extra-axial spaces, which now had echogenic debris. Color Doppler US showed bridging veins traversing these extra-axial spaces, so it was initially thought that these spaces were subarachnoid in nature (positive cortical vein sign). However, an arachnoid membrane was identified superior to the cortex, and there was compression of true cortical vessels beneath this dural membrane. An MRI of the brain showed the extra-axial spaces to represent bilateral subdural hematomas. The pathogenesis of spontaneous development of the subdural hematomas, in the setting of BIH, is discussed. We also emphasize that visualizing traversing bridging veins through extra-axial spaces does not necessarily imply that these spaces are subarachnoid in origin.     

Regulation of synaptic plasticity in a schizophrenia model

The pathology of schizophrenia is characterized by increased hippocampal activity at baseline and during auditory hallucinations. Animal-model studies in which the flow of activity to the hippocampus is increased through decreased amygdalar GABAergic inhibition have shown alterations of hippocampal circuitry similar to schizophrenia, but the functional importance of this phenomenon remains unclear. We provide evidence of decreased hippocampal feed-forward and tonic GABA-mediated inhibition in this animal model, complementing increased hippocampal activity seen in neuroimaging and postmortem studies. We demonstrate that GABA dysfunction increases long-term potentiation through activation of the cholinergic system, offering a new mechanism for pharmacological strategies of this disorder.