Regional anesthesia techniques for pain control in the intensive care unit

The judicious use of regional anesthesia in the intensive care unit should improve patient comfort. Techniques covered include intercostal nerve blocks, interpleural blocks, paravertebral blocks, brachial plexus blocks, and femoral nerve blocks. Rational patient selection for each technique mentioned is also discussed.     

Astrocytic glutamate uptake and prion protein expression

Factors influencing glutamate uptake by astrocytes may indirectly influence neuronal survival. Elevated extracellular glutamate may be excitotoxic or may exacerbate neurodegeneration in various neurological diseases. By using a cell culture model, we have investigated the influence of astrocytic prion protein (PrPc) expression on glutamate uptake. Type 1 astrocytes expressing PrPc have a higher rate of Na+-dependent glutamate uptake than PrPc-deficient type 1 astrocytes. This difference is exacerbated when serum free media is used to culture the astrocytes. Further analysis suggested that a decrease in substrate affinity is responsible for the sensitivity of PrP-deficient astrocytic glutamate uptake to culture conditions. PrPc has been shown to bind copper. Greater sensitivity of cells to copper concentrations may be responsible for the decreased substrate affinity observed. PrPc-deficient cerebellar cells are more sensitive to glutamate toxicity in the presence of copper. These results show that glutamate uptake from astrocytes is dependent on PrPc expression which in turn may be related to copper metabolism.     

Regulatory factors associated with synthesis of the osmolyte glycine betaine in the halophilic methanoarchaeon Methanohalophilus portucalensis

The halophilic methanoarchaeon Methanohalophilus portucalensis can synthesize de novo and accumulate beta-glutamine, Nepsilon-acetyl-beta-lysine, and glycine betaine (betaine) as compatible solutes (osmolytes) when grown at elevated salt concentrations. Both in vivo and in vitro betaine formation assays in this study confirmed previous nuclear magnetic resonance 13C-labelling studies showing that the de novo synthesis of betaine proceeded from glycine, sarcosine, and dimethylglycine to form betaine through threefold methylation. Exogenous sarcosine (1 mM) effectively suppressed the intracellular accumulation of betaine, and a higher level of sarcosine accumulation was accompanied by a lower level of betaine synthesis. Exogenous dimethylglycine has an effect similar to that of betaine addition, which increased the intracellular pool of betaine and suppressed the levels of Nepsilon-acetyl-beta-lysine and beta-glutamine. Both in vivo and in vitro betaine formation assays with glycine as the substrate showed only sarcosine and betaine, but no dimethylglycine. Dimethylglycine was detected only when it was added as a substrate in in vitro assays. A high level of potassium (400 mM and above) was necessary for betaine formation in vitro. Interestingly, no methylamines were detected without the addition of KCl. Also, high levels of NaCl and LiCl (800 mM) favored sarcosine accumulation, while a lower level (400 mM) favored betaine synthesis. The above observations indicate that a high sarcosine level suppressed multiple methylation while dimethylglycine was rapidly converted to betaine. Also, high levels of potassium led to greater amounts of betaine, while lower levels of potassium led to greater amounts of sarcosine. This finding suggests that the intracellular levels of both sarcosine and potassium are associated with the regulation of betaine synthesis in M. portucalensis.     

Experiences with mixed integer linear programming based approacheson short-term hydro scheduling

This paper describes experiences with mixed integer linear programming (MILP) based approaches on the short-term hydro scheduling (STHS) function. The STHS is used to determine the optimal or near-optimal schedules for the dispatchable hydro units in a hydro-dominant system for a user-definable study period at each time step while respecting all system and hydraulic constraints. The problem can be modeled in detail for a hydro system that contains both conventional and pumped-storage units. Discrete and dynamic constraints such as unit startup/shutdown and minimum-up/minimum-down time limits are also included in the model for hydro unit commitment (HUC). The STHS problem is solved with a state-of-the-art package which includes an algebraic modeling language and a MILP solver. The usefulness of the proposed solution algorithm is illustrated by testing the problem with actual hydraulic system data. Numerical experiences show that the solution technique is computationally efficient, simple, and suitable for decision support of short-term hydro operations planning. In addition, the proposed approaches can be easily extended for scheduling applications in a deregulated environment     

Reproductive performance of dairy heifers after estrus synchronization and fixed-time artificial insemination.

The reproductive performance of heifers after estrus synchronization and fixed-time AI was compared with nonsynchronized heifers in 25 spring-calving herds. Within herds, heifers were divided into a synchronized (n = 1123) or a control (n = 1125) group. Heifers in the synchronized group were treated with a combination of progesterone, estradiol benzoate, and PGF2 alpha and were inseminated between 50 and 54 h after progesterone treatment. Returns to first service were resynchronized with progesterone treatment between 16 and 21 d after the fixed-time AI. The conception rate of synchronized heifers to the fixed-time AI (53.2%) and to AI after resynchronization (53.1%) was lower than that of control heifers (63.7%). However, pregnancy rate in the first 24 d was higher for the synchronized group (72.4%) than for the control group (67.8%). More control heifers (5.7%) than synchronized heifers (4.0%) failed to conceive. The interval from start of breeding to calving was earlier for synchronized (296.2 d) than for control (299.5 d) heifers. Jersey heifers had lower reproductive performance than did Friesian heifers. Synchronized heifers gave birth to more female calves (53.8%) than did control heifers (45.7%). It is concluded that the above program can be used successfully to synchronize dairy heifers for fixed-time AI.     

Limited humoral immunity in hepatitis C virus infection

BACKGROUND & AIMS: The extremely high rate of chronicity to hepatitis C virus (HVC) infection suggests an inefficient immune response. The humoral immune response to HCV was evaluated in 60 patients with chronic HCV infection and in 12 patients acutely infected with HCV. METHODS: A number of recombinant HCV antigens including the core, envelope 2 (E2), nonstructural (NS) 3, NS4, and NS5 proteins, and NS4a and E2-HVR-1 peptides were used in enzyme-linked immunoassays. RESULTS: Immunoglobulin (Ig) G antibody responses to these viral antigens, except for the HCV core, were highly restricted to the IgG1 isotype. The prevalence of antibodies of the IgG1 isotype specific for the HCV core, E2, E2-HVR1, NS3 (helicase domain), NS4, and NS5 antigens was 97%, 98%, 28%, 88%, 33%, and 68%, respectively. Antibodies of the IgG3 isotype specific for E2, E2-HVR-1, NS3, NS4, and NS5 were detected in a minority of serum samples. The IgG2 and IgG4 isotypes were rarely if ever detected. Furthermore, antibody responses to HCV viral antigens were of relatively low titer and, with the exception of anti-HCV core, were delayed in appearance until the chronic phase of infection. CONCLUSIONS: The IgG1 restriction, low titer, and delayed appearance of antibody responses elicited during HCV infection suggest that the immunogenicity of HCV proteins is limited in the context of natural infection. Inasmuch as recombinant HCV viral antigens perform as relatively normal immunogens in small animals, we suggest that the defective humoral immune responses during HCV infection may be attributable to an "immune avoidance" strategy.     

The effect of extended‐hours hemodialysis on outcomes: A systematic review and meta‐analysis

Extended‐hours hemodialysis is associated with improvements in quality of life (QoL) and mortality, but it may accelerate the loss of residual kidney function (RKF) and increase vascular access complications. Multiple established databases were systematically searched; randomized and non‐randomized studies were pooled separately. QoL outcomes were assessed using standardized mean difference (SMD), vascular access adverse events and mortality were assessed with relative risk ratios (RR). Four hundred seventy‐six patients from six trials were eligible. Data from randomized controlled trials (RCTs) could only be synthesized for vascular access adverse events and mortality, which demonstrated no significant change in vascular access adverse events (RR 1.25, 95% CI 0.88 to 1.77) or mortality (RR 2.29, 95% CI 0.60 to 8.71). Pooled data from non‐randomized trials demonstrated no significant difference in QoL (SF‐36 Physical Component Summary SMD 0.61, 95% CI ?0.10 to 1.31, SF‐36 Mental Component Summary SMD ?0.04, 95% CI ?0.61 to 0.54). RKF was assessed in one report which demonstrated a potential reduction over 12 months with extended‐hours hemodialysis. The majority of trials had high risk of bias. Extended‐hours hemodialysis was not associated with improved QoL or mortality, or increased vascular access events. Adequately powered RCTs are needed to fully assess extended‐hours hemodialysis.     

Application of physiologic models to predict the influence of changes in body composition and blood flows on the pharmacokinetics of fentanyl and alfentanil in patients

This chapter reviews the importance of information management in a therapeutic community, how to select the data collected by the interview and features of the software and its fitting in an operative context. New sections are projected to help staff who diagnose treatment candidates and treat patients. Use of statistical analysis as an instrument for management of therapeutic communities is based on the experience of "Centro Solidarietà di Modena". Some examples are included on the population of "Centro Solidarietà di Modena". Artificial neural networks have a viable role for treatment (primary, secondary and tertiary).     

In vivo imaging of brain nicotinic acetylcholine receptors with 5-[123I]iodo-A-85380 using single photon emission computed tomography

The distribution and kinetics of 5-[123I]iodo-A-85380, a novel ligand for brain nicotinic acetylcholine receptors (nAChRs), were evaluated in the Rhesus monkey using single photon emission computed tomography (SPECT). Peak levels of radioactivity were measured in brain at 90 min after injection of the tracer. Accumulation of radioactivity was highest in the thalamus, intermediate in the frontal cortex and basal ganglia, and lowest in the cerebellum. The ratio of specific to nonspecific binding (V3") in the thalamus, estimated from the (thalamic-cerebellar)/cerebellar radioactivity ratio, reached a value of 6 at 4 h post-injection. Specific binding was reduced by subcutaneous injection of 1 mg/kg cytisine at 2.25 h after injection of radiotracer. At 2.5 h after cytisine administration, radioactivity in the thalamus was reduced by 84%, in the frontal cortex, by 76%, and in the basal ganglia, by 57% of the level measured at the time of cytisine administration, demonstrating that the binding was reversible. On the basis of these findings, together with other data indicating high affinity, receptor subtype selectivity, low nonspecific binding and lack of toxicity in animals, 5-[123I]iodo-A-85380 appears to be a promising ligand for SPECT imaging of nAChRs in the human brain.     

Identification and control of induction motor stator currents usingfast on-line random training of a neural network

Artificial neural networks (ANNs), which have no off-line pretraining, can be trained continually on-line to identify an inverter-fed induction motor and control its stator currents. Due to the small time constants of the motor circuits, the time to complete one training cycle has to be extremely small. This paper proposes and evaluates a new form of the random weight change (RWC) algorithm, which is based on the method of random search for the error surface gradient. Simulation results show that the new form of the RWC, termed continually online trained RWC (COT-RWC), yields performance very much the same as conventional backpropagation with on-line training. Unlike backpropagation, however, the COT-RWC method can be implemented in mixed digital/analog hardware and still have a sufficiently small training cycle time. The paper also proposes a VLSI implementation which completes one training cycle in as little as 8 μs. Such a fast ANN can identify and control the motor currents within a few milliseconds and, thus, provide self-tuning of the drive while the ANN has no prior information whatsoever of the connected inverter and motor