Is Post Cardiopulmonary Bypass Dysfunction a Special Form of Stunning?

Abstract It has been suggested that cardioplegic arrest during cardiopulmonary bypass (CPB) produces global myocardial ischemia with a risk of myocardial stunning. It has also been postulated that anesthetic technique may affect the course of post-CPB myocardial stunning via exaggerated myocardial depression. However, we have previously found that global ventricular and regional myocardial responses to halothane do not differ in post-CPB and pre-CPB dogs. Our examination of the effects of CPB on the beta-adrenergic function revealed that beta-adrenergic receptor function is only slightly decreased immediately following (i.e., 1 min) and 30 minutes post-CPB. A dose-response relationship was established for dobutamine, with decreased responsiveness noted at both times. Since other data show normal inotropic stimulation of stunned myocardium, decreases in dobutamine responsiveness cannot be explained by beta-receptor desensitization. Overall, these data indicate that CPB does not result in myocardial stunning. The differences between these data and others showing myocardial stunning following CPB may be due to several factors, such as anesthetic regimen, lack of coronary blood flow abnormalities, and a reduction in sarcoplasmic reticular damage due to the hypothermic conditions used.     

Echo-guided percutaneous puncture: a safe and valuable therapeutic tool for amebic liver abscess

To clarify the therapeutic role of echo-guided percutaneous puncture (EPP) in management of amebic liver abscess, 20 patients (24 abscesses) received metronidazole plus EPP. Fluid was aspirated through Chiba needles under real-time sonographic guidance so as to reduce cavity size to less than 3 cm. Not more than two EPPs were necessary in the majority of cases and no complication followed the procedure. This scheme resulted in a shortening of time of both hospitalization (less than or equal to 20 days) and liver lesion healing as assessed by ultrasound (less than or equal to 4 months). It is concluded that EPP is a valuable and safe therapeutic tool for hepatic amebic abscess.     

Optic nerve pseudomeningioma secondary to localized amyloidosis

A 55-year-old woman presented with a mass of the optic nerve sheath suggestive of a meningioma. On excision, this proved to be amyloid. No systemic involvement could be found. Although amyloid may arise as a solitary lesion of the orbit or extraocular muscle, this "pseudomeningiomatous" pattern has not been previously noted. A magnetic resonance scan was helpful because the amyloid imaged at a density similar to vitreous and cerebral white matter, unlike meningiomas, which appear more like bone. The diagnosis of localized amyloidosis, however, still remains dependent on histopathology and cannot be made on a clinical basis.     

Effect of medication in Parkinson's disease: a wavelet analysis of EMG signals

The improvements in the motor ability in patients with Parkinson's disease due to antiparkinsonian medication is well-known and widely documented. Recent results, based both on kinematic parameters and standard electromyographic (EMG) signal analysis, clearly indicated that the medication reduced, as expected, the clinical signs of Parkinson's disease, but did not restore agonist burst duration modulation with distance in elbow flexion movements. The main aim of the present work is to shed more light on this medication effect using a wavelet analysis approach on multiple EMG signals recorded both on shoulder and elbow muscles in ballistic or rapid movements. The wavelet cross-correlation information allows us to evidence some important quantitative features of the EMG signals due to medication.     

In vitro and in vivo modulation of MDR1/P-glycoprotein in HIV-infected patients administered highly active antiretroviral therapy and liposomal doxorubicin

P-glycoprotein (P-gp) transports a wide range of structurally unrelated drugs, such as HIV protease inhibitors (PIs) and cytotoxic compounds such as anthracyclines. Because modification of P-gp phenotype and function is an important underlying mechanism of drug interactions, the current study was conducted in order to evaluate whether highly active antiretroviral therapy (HAART), HIV plasma viral load (VL), or cancer chemotherapy may induce in vivo changes of P-gp phenotype in peripheral blood mononuclear cells (PBMCs) from HIV-infected treatment-naive and -experienced subjects at different stages of HIV infection and/or disease, including patients with HIV-associated Kaposi sarcoma (KS). Our results show that neither HAART nor HIV VL, nor the stage of HIV infection and/or disease, significantly alter P-gp expression on PBMCs. In particular, surface P-gp expression is expressed at low levels by T-cell subsets, B cells, and NK cells, whereas almost all monocytes are double positive and these results are not modified by HIV PI-containing regimens. By contrast, a significant phenotype modification is detected in PBMCs from AIDS/KS patients after challenge with the liposomal formulation of the anthracycline doxorubicin (L-DOX) with the higher expression reached 24 hours after the end of the drug infusion. In addition, accumulation of L-DOX is unaffected by P-gp-mediated drug efflux as documented by in vitro experiments, in sharp contrast to the kinetic of free DOX, based on HIV PI blockade experiments. Finally, P-gp expression was found in KS spindle cells from HIV-infected treatment-naive AIDS/KS patients. We conclude that P-gp phenotype in PBMCs and specific subsets is not altered by HAART and/or HIV, whereas a significant increase is induced by specific anticancer drugs such as L-DOX. Moreover, HIV PIs possess an inhibitory effect on P-gp function that may improve DOX sensitivity in KS spindle cells.     

Stimulation of NaCl reabsorption by antidiuretic hormone in the cortical thick ascending limb of Henle's loop of the mouse

The effect of antidiuretic hormone (ADH) on transepithelial Na⁺, Cl^–, Ca²⁺ and Mg²⁺ net fluxes (J_Na, J_Cl, J_Mg, J_Ca) was investigated in isolated perfused cortical thick ascending limb segments (cTAL) of the mouse nephron, using the microperfusion technique and the electron microprobe analysis to determine the ionic composition of the collected tubular fluid. Simultaneously, the transepithelial potential difference (PD_te) and the transepithelial resistance (R_te) were recorded. Prior to the flux measurements cTAL segments were perfused for one hour. During this equilibration period PD_te decreased significantly from +19.9±1.6 to +14.9±1.l mV and R_te increased from 30.6±3.5 cm² to 38.8±2.4 cm² (n=7), reflecting a decline in NaCl transport. After ADH was added to the bath solution at 10^–10 mol.l^–1, PD_te increased from +14.4±1.1 to +18.0±1.5 mV, accompanied by a rise in J_Na and J_Cl from 205±11 to 273±19 and from 216±12 to 283±21 pmol.min^–1.mm^–1 (n=7), respectively. J_Ca and J_Mg also increased from 0.81±0.07 to 1.50±0.12 and from 0.43±0.11 to 0.76±0.08 pmol.min^–1.mm^–1 (n=7), respectively. All these effects were fully reversible after withdrawal of the hormone. In conclusion our data indicate that ADH stimulates divalent cation transport and NaCl transport in the cortical thick ascending limb of Henle's loop of the mouse.