When Is a Bispectral Index of 60 Too Low?: Rational Processed Electroencephalographic Targets Are Dependent on the Sedative-Opioid Ratio

Background: Opioids are commonly used in conjunction with sedative drugs to provide anesthesia. Previous studies have shown that opioids reduce the clinical requirements of sedatives needed to provide adequate anesthesia. Processed electroencephalographic parameters, such as the Bispectral Index (BIS; Aspect Medical Systems, Newton, MA) and Auditory Evoked Potential Index (AAI; Alaris Medical Systems, San Diego, CA), can be used intraoperatively to assess the depth of sedation. The aim of this study was to characterize how the addition of opioids sufficient to change the clinical level of sedation influenced the BIS and AAI.

Methods: Twenty-four adult volunteers received a target-controlled infusion of remifentanil (0-15 ng/ml) and inhaled sevoflurane (0-6 vol%) at various target concentration pairs. After reaching pseudo-steady state drug levels, the modified Observer's Assessment of Alertness/Sedation score, BIS, and AAI were measured at each target concentration pair. Response surface pharmacodynamic interaction models were built using the pooled data for each pharmacodynamic endpoint.

Results: Response surface models adequately characterized all pharmacodynamic endpoints. Despite the fact that sevoflurane-remifentanil interactions were strongly synergistic for clinical sedation, BIS and AAI were minimally affected by the addition of remifentanil to sevoflurane anesthetics.     

3He MRI in mouse models of asthma.

In the study of asthma, a vital role is played by mouse models, because knockout or transgenic methods can be used to alter disease pathways and identify therapeutic targets that affect lung function. Assessment of lung function in rodents by available methods is insensitive because these techniques lack regional specificity. A more sensitive method for evaluating lung function in human asthma patients uses hyperpolarized (HP) (3)He MRI before and after bronchoconstriction induced by methacholine (MCh). We now report the ability to perform such (3)He imaging of MCh response in mice, where voxels must be approximately 3000 times smaller than in humans and (3)He diffusion becomes an impediment to resolving the airways. We show three-dimensional (3D) images that reveal airway structure down to the fifth branching and visualize ventilation at a resolution of 125 x 125 x 1000 microm(3). Images of ovalbumin (OVA)-sensitized mice acquired after MCh show both airway closure and ventilation loss. To also observe the MCh response in naive mice, we developed a non-slice-selective 2D protocol with 187 x 187 microm(2) resolution that was fast enough to record the MCh response and recovery with 12-s temporal resolution. The extension of (3)He MRI to mouse models should make it a valuable translational tool in asthma research.     

Beta-endorphin plasma levels and their dependence on gender during an enteral glucose load in lean subjects as well as in obese patients before and after weight reduction

It is speculated that endogenous opioid peptides are involved in glucose metabolism and that their homeostasis might be disturbed in obesity. Despite a different response of the pancreatic beta-cells after beta-endorphin and naloxone injections between obese patients and normal weight controls, there is little knowledge concerning the direct influence of a glucose load on beta-endorphin plasma levels, especially with respect to various nutrition states. During exploration of this topic we gained further insight on the difference of basal beta-endorphin plasma levels between normal and overweight persons. We compared beta-endorphin plasma levels during an oral glucose load in 60 obese, non-diabetic patients and in 20 normal weight controls. We also studied 40 of the obese patients after a weight reduction of 2.1 kg/m2. The following results were obtained: (1) Normal weight females have significantly lower (P less than 0.05) basal beta-endorphin levels compared to the male controls. This difference in gender is abolished in obesity where female and male patients do not differ in basal beta-endorphin plasma levels. Therefore, the difference between normal and overweight persons in beta-endorphin plasma levels was restricted to the subgroup of females. We suppose that former neglect of this difference in gender explains most of the so far reported discrepant results. (2) During the oral glucose tolerance test the beta-endorphin plasma values remained constant in the obese group. Despite improved insulin sensitivity after weight reduction there was still no change of beta-endorphin plasma levels both during the OGTT and when compared to the values before weight reduction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Antiarrhythmic active amidinohydrazones of substituted benzophenones. 4. The photoisomerization of (Z)- and (E)-2-amino-5-chlorobenzophenone amidinohydrazones and the corresponding (E)-N-phenylamidinohydrazone]

The title compounds undergo a photoisomerization by irradiation. If the E-isomers are irradiated by light of a wavelength of an absorption maximum typical for them, they can be converted quantitatively to the corresponding Z-isomers. In case that the synthesis of analogs of the title compounds give only one configurational isomer, sometimes the missing one can be obtained by photoisomerization.     

Ductus aneurysm as a rare cause of inspiratory stridor in the newborn infant

A paralysis of the left vocal cord was seen by laryngoscopy in a 3-days-old boy with inspiratory stridor. A ductus aneurysm was established by angiocardiography, which was believed to be the cause of the vocal cord paralysis. Within 8 days after the angiocardiography the aneurysm became smaller and the stridor disappeared. Twelfth months later the control-angiocardiography showed the total obliteration of the ductal aneurysm.     

Development of a new dynamic method for quantitative evaluation of in vitro hemocompatibility of biomedical materials.

In this study a new dynamic method is introduced allowing the estimation of blood cell adhesion on flat test surfaces by measuring the cell loss in the bulk phase of surface contacting test blood under defined rheological conditions. This was achieved by constructing a novel test chamber permitting the contact of small amounts of blood with a large geometrical test surface. The construction consists of a spiral-shaped flow channel of 0.3 cm width, 0.02 cm height and 78 cm length covered with the biomaterials to be tested from both sides. Laminarity of blood flow in the conduit was confirmed theoretically by the calculation of an equivalent to the Reynolds number for curved systems the so-called Dean number. Furthermore, flow laminarity was proved experimentally finding that the flow rate of blood with different hematocrit values was proportional to the hydrostatic pressure applied. The applicability of the novel 'spiral method' for the estimation of hemocompatibility was demonstrated by evaluation of platelet adhesion onto different polymers in comparison to siliconized and fibrinogen coated glass as reference surfaces. Additionally, it was possible under distinct conditions to determine the adhesion of leucocytes and the detachment of platelet aggregates. Therefore, it was concluded that the spiral method can be used for the assessment of the hemocompatibility of flat biomedical polymers. As main advantages of the new method can be considered the high time efficiency and accuracy without labelling or optical detection of adherent cells.     

Comparative studies of the activity of disaccharidases in the mucosa of the small intestines in dystrophic, formerly hypotrophic-born young children and of patients with flat mucosa of various etiology

The disaccharidase activities of the mucous membrane of the small intestine were determined in formerly hypotrophic children who showing a dystrophy with a morphological normal mucosa (n = 36), patients with a flat mucosa caused by enteral protein intolerances of different genesis (n = 27), patients with a morphologically and functionally normal mucosa (n = 51). In about half of the former small-for-date children were shown activities lower than the simple standard deviation of the normal value, for lactase n = 17, for sucrase n = 14, for maltase n = 12. Some children showed pathologically reduced activities even below the double standard deviation for the normal value: lactase n = 8, sucrase n = 5, maltase n = 3.