Circulatory mechanisms of shock and their mediators

Traditional concepts of shock therapy have been based on conventional monitoring. However, the availability of invasive monitoring systems has provided the means to describe the patterns of oxygen transport in various acute life-threatening illnesses. Surgical trauma provides a useful model for investigation of other shock syndromes, because measurements may be made in the preoperative control period, during the hemodynamic crisis intraoperatively, and sequentially throughout the postoperative period for survivors and nonsurvivors. This provides a time-related pattern of physiologic events that may form the basis for the physiologic evaluation of mechanisms operative in survivors and nonsurvivors. Physiologic alterations which are compensatory may be identified from the survivor pattern and differentiated from decompensations associated with the lethal course. The DO2 pattern reflects circulatory functional changes which may limit body metabolism as reflected by VO2. The body compensates for tissue hypoxia and increased metabolic needs by increased flow and DO2 in sepsis and trauma, and by increased oxygen extraction in hemorrhagic and cardiogenic shock where flow is limited. The interactions of survivors' hemodynamic and oxygen transport patterns define compensatory responses which primarily are increased cardiac output, DO2, and VO2. Inadequate compensations and decompensations of shock are clearly manifest by the nonsurvivor pattern. Therapeutic goals may be defined by the values of the survivor patterns; reduced mortality and morbidity result when these goals are vigorously applied prospectively (17-19).     

成都市新都区餐饮具消毒效果监测

为了解餐饮具消毒现状,采用纸片检验法对新都区饮食单位餐饮具消毒效果进行了监测。结果,抽检餐饮单位297户,餐饮具样本1914份,总合格率为73.51％;抽检全部合格的单位占43.43％,全部不合格的单位占8.08％。结果显示,新都区餐饮业消毒效果和卫生状况整体水平较低,其中以中餐业和中等规模餐饮店卫生状况最差。因此,必须加强管理,加大监督监测力度,全面落实消毒和卫生管理制度,改进餐饮业卫生质量。     

Hemiplegic migraine during pregnancy: unusual magnetic resonance appearance with SPECT scan correlation

OBJECTIVE: This article discusses the pathophysiology and implications for treatment of hemiplegic migraine within a case study presentation. BACKGROUND: We evaluated a 31-year-old white woman for hemiplegia in her 36th week of pregnancy. She initially presented with severe headache, dysarthria, lethargy, and left-sided numbness and weakness. Hemiplegic migraine remains a diagnosis made by exclusion; neurologic examination of these patients is localizing, but nonspecific. DESIGN: Magnetic resonance imaging and single photon emission computed tomography scanning were performed on this patient during an exacerbation of headache associated with dense hemiplegia. RESULTS: Magnetic resonance imaging showed a superficial cerebral hemispheric signal abnormality with enhancement. Single photon emission computed tomography scanning confirmed hyperperfusion of that hemisphere. CONCLUSIONS: We believe the imaging evidence in our patient suggests that hemiplegia was caused and sustained by hyperperfusion. This case lends supportive evidence to a primarily vasodilatory mechanism and hyperperfusion as an etiology of the paralysis in such headaches and perhaps migraine with aura.     

Evaluation of a real-time fluorescent PCR assay for rapid detection of Group B Streptococci in neonatal blood

Streptococcus agalactiae (Group B Streptococcus: GBS) is the major causative agent of neonatal sepsis. Neonates at risk for GBS infections are empirically administered broad-spectrum antibiotics for at least 48 h pending blood culture results. A rapid assay to expedite detection of GBS would facilitate initiation of specific antibiotic therapy. Conversely, expeditious proof of absence of infection will avoid unnecessary antibiotic use. Using the LightCycler, we evaluated a hybridization probe polymerase chain reaction (PCR) assay to detect GBS-specific cfb gene target DNA sequence in blood specimens. Both sensitivity and specificity of the real-time PCR assay was 100%. The assay demonstrated 100% specificity when tested against 26 non-GBS bacteria. This method is capable of detecting as few as approximately 100 copies or 10 pg of GBS genomic DNA. This real-time PCR method is rapid, sensitive, and specific for the detection of GBS in neonatal blood samples and holds great promise in its utility in the diagnostic laboratory.     

Comparison of measurements of cardiac output by bioimpedance and thermodilution in severely ill surgical patients

In order to evaluate a new thoracic electrical bioimpedance (TEB) system for measurement of stroke volume based on the Sramek-Bernstein equation, 391 paired values of cardiac output were measured simultaneously with the standard thermodilution method. These values were obtained from 16 patients selected for having the most severe illness during a 6-month period; the intent was to evaluate the bioimpedance method in the worst possible situations. The correlation coefficient (r) was 0.83, slope was 0.87, intercept was 1.53, and the mean difference between the two methods was 16.2 +/- 11.8 (SD)% in the total series. In 285 paired samples where satisfactory conditions were met, r was 0.90, slope was 0.98, intercept was 0.34, and the mean difference was 11.8 +/- 8.9%. The data indicate satisfactory correlations between these two methods. When the TEB waveform is satisfactory, the agreement between TEB and thermodilution is as good as the agreement between serial thermodilution methods. Difficulties may arise with dysrhythmias, tachycardia (heart rate greater than 150 beat/min), metal in the chest or chest wall, sepsis, hypertension, and extremely oily skin. Mechanical ventilation did not appear to be a problem.     

Striatonigral control of movement velocity in mice

The basal ganglia have long been implicated in action initiation. Using three‐dimensional motion capture, we quantified the effects of optogenetic stimulation of the striatonigral (direct) pathway on movement kinematics. We generated transgenic mice with channelrhodopsin‐2 expression in striatal neurons that express the D1‐like dopamine receptor. With optic fibres placed in the sensorimotor striatum, an area known to contain movement velocity‐related single units, photo‐stimulation reliably produced movements that could be precisely quantified with our motion capture programme. A single light pulse was sufficient to elicit movements with short latencies (<30 ms). Increasing stimulation frequency increased movement speed, with a highly linear relationship. These findings support the hypothesis that the sensorimotor striatum is part of a velocity controller that controls rate of change in body configurations.     

Transcutaneous O2 and CO2 monitoring of high risk surgical patients during the perioperative period

The usefulness of noninvasive transcutaneous oxygen (PtcO2) and carbon dioxide (PtcCO2) sensors as well as invasive monitoring of flow and oxygen transport were evaluated in the perioperative period of a small series of high risk surgical patients. We used the pattern of physiological events preceding intraoperative death as the criteria for evaluation of the relative usefulness of these variables. Cardiac output (CO), oxygen delivery (DO2), and O2 consumption (VO2) provided the earliest warning of impending circulatory deterioration and were most useful during critical nonlethal circulatory episodes; these were closely paralleled by the PtcO2 index (PtcO2/PaO2); the PtcCO2 was less sensitive. Heart rate (HR) and mean arterial pressure (MAP) were highly variable with frequent changes unrelated to change in flow and O2 transport.     

Acetyl glyceryl ether phosphorylcholine-stimulated human platelets cause pulmonary hypertension and edema in isolated rabbit lungs. Role of thromboxane A2.

Macrophages, neutrophils, and platelets may play a role in acute edematous lung injury, such as that seen in the adult respiratory distress syndrome (ARDS), but their potential actions and interactions are unclear. Because stimulated human macrophages and neutrophils can release acetyl glyceryl ether phosphorylcholine (AGEPC), a potent platelet activator, we hypothesized that in ARDS, leukocyte release of AGEPC might stimulate platelets to release thromboxane A2 (TXA2), which then produces pulmonary hypertension and lung edema. In support of this premise, we found that pulmonary hypertension and edema occurred in isolated rabbit lungs perfused with human platelets and AGEPC, but not with platelets or AGEPC alone. Infusion of a vasodilator (nitroglycerin) to maintain base-line pulmonary artery pressures in lungs perfused with platelets and AGEPC prevented the development of lung edema suggesting that platelet and AGEPC-induced edema was hydrostatic in nature. Additional experiments suggested that the increased pressure was a result of TXA2 release from platelets stimulated by AGEPC. Specifically, preincubation of platelets with imidazole, a thromboxane synthetase blocker, prior to infusion with AGEPC significantly diminished pulmonary hypertension and prevented lung edema. Furthermore, pretreating lung preparations with 13-azaprostanoic acid, a TXA2 antagonist, before infusion of AGEPC and untreated platelets also reduced the pulmonary hypertension and blocked the lung edema. The role of TXA2 was further suggested when perfusates from lungs infused with platelets and AGEPC developed high levels of TXA2, whereas perfusates from controls did not. These results suggest that platelet aggregation induced by AGEPC may contribute to ARDS by releasing TXA2, which raises microvascular pressure and increases edema formation, especially when an underlying permeability defect is present.