Differences in aerodynamic characteristics of new and dysfunctional Provox®2 voice prostheses in vivo

Tracheoesophageal voice prostheses need to be replaced due to increased airflow resistance or retrograde leakage of fluid into the trachea as a consequence of biofilm formation. Previous in vitro studies show a change of aerodynamic features of biofilm covered voice prostheses after removal of the prostheses out of the patient. To assess these changes in an in situ situation, aerodynamic characteristics were measured within 45 patients at the beginning and at the end of the wearing process of the Provox 2 voice prosthesis. As a consequence, the influence of biofilm formation on aerodynamic characteristics can be evaluated. In the majority of cases, leakage through the prosthesis was the reason for replacement. No differences were found in the total flow, volume range and intratracheal pressure (ITP) of the voice prostheses measured. The airflow resistance of biofilm covered prostheses was significantly reduced compared to new clean prostheses. However, no correlation was found between the extent of biofilm and the different aerodynamic features measured. Biofilm formation on the Provox 2 is responsible for both reduction in airflow resistance and leakage through the prosthesis by deterioration of the silicone rubber material.     

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)     

2-(3-Halogen-4-hydroxyphenyl)-1,4-napthoquinone derivatives from 2-(3,5-di-tert-butyl-4-hydroxyphenyl)-analogs, potent 5-lipoxygenase inhibitors. 27. 1,4-Naphthoquinones]

A new simple and fast method for the synthesis of halogenated hydroxyphenyl naphthoquinones as potential 5-lipoxygenase (LOX) inhibitors is presented. While the aryl naphthoquinone 1, a potent 5-LOX inhibitor, with AlCl3 is debutylated to 2a and 2b, the oxidized cyclohexadienylidene derivative 3 reacts comparably by concomitant halogenation to 4a and with AlBr3 to 4b, respectively. As products of a side reaction of 6 with TiCl4 and BBr3 the tetracyclic benzo[b]naphthol[2,1-d]furan derivatives 8a and 8b are isolated. Selected compounds are investigated for 5-lipoxygenase inhibiting and antioxidative properties. There is a clear-cut correlation of both qualities in those compounds with a 3-OH function and with two, one or without any tert-butyl group at the phenyl moiety. In contrast the quinone 6 (3-Cl) and the dibenzofuran 8a are powerful 5-LOX inhibitors with only low antioxidative activity.     

Rapid tolerance and locomotor sensitization in ethanol-naïve adolescent rhesus macaques

Background: Acute and chronic tolerance, as well as locomotor sensitization, have been linked to ethanol intake. This study examined the change in response between 2 acutely administered doses of ethanol in adolescent rhesus macaques, with the objective of investigating rapid tolerance and locomotor sensitization to the behavioral effects of ethanol, and whether these phenomena are related to voluntary ethanol consumption in nonhuman primates. Methods: Rhesus macaques (n = 109, 42 males, 67 females) were administered 2 sequential intravenous doses of ethanol (2.2 g/kg for males, 2.0 g/kg for females) separated by a period of 5 to 30 days. Following each injection, subjects underwent a 30‐minute behavior assessment. Behavioral data were summarized using factor analysis, and compared between the 2 doses using repeated measures ANOVA. The relationship between behavioral response measures and the number of days between doses was analyzed using regression analyses. Following the second ethanol dose, subjects were given free access to an aspartame‐sweetened 8.4% ethanol solution for 1 hour a day for 4 weeks. Percent change in behavioral response measures from dose 1 to dose 2 was analyzed for associations with ethanol consumption using multiple regression analyses. Results: Factor analysis yielded 3 factors: ataxia, stimulation, and jumping. From dose 1 to dose 2 there was a significant decrease in ataxia and a significant increase in stimulation. Peak blood ethanol concentration did not differ between doses. There were no significant associations between the number of days between doses and the magnitude of change in response for any of the behavioral measures. Percent change in stimulation from dose 1 to dose 2 was positively associated with subsequent oral ethanol consumption only in females tested in a social setting. Conclusions: Adolescent rhesus macaques develop rapid tolerance to the motor‐impairing effects of alcohol, while at the same time developing locomotor sensitization. These changes in response are not necessarily short lived, and may persist for some time following the first ethanol dose. Clear and consistent associations between rapid tolerance and locomotor sensitization and ethanol intake levels have yet to be demonstrated, however.     

Presurgical selection of the ideal aneurysm clip by the use of a three-dimensional planning system

Aneurysm occlusion rate after clipping is higher than after endovascular treatment. However, a certain percentage of incompletely clipped aneurysms remains. Presurgical selection of the proper aneurysm clips could potentially reduce the rate of incomplete clippings caused by inadequate clip geometry. The aim of the present study was to assess whether preoperative 3D image-based simulation allows for preoperative selection of a proper aneurysm clip for complete occlusion in individual cases. Patients harboring ruptured or unruptured cerebral aneurysms prior to surgical clipping were analyzed. CT angiography images were transferred to a 3D surgical-planning station (Dextroscope®) with imported models of 58 aneurysm clips. Intracranial vessels and aneurysms were segmented and the virtual aneurysm clips were placed at the aneurysm neck. Operating surgeons had information about the selected aneurysm clip, and patients underwent clipping. Intraoperative clip selection was documented and aneurysm occlusion rate was assessed by postoperative digital subtraction angiography. Nineteen patients were available for final analysis. In all patients, the most proximal clip at the aneurysm neck was the preselected clip. All aneurysms except one were fully occluded, as assessed by catheter angiography. One aneurysm had a small neck remnant that did not require secondary surgery and was occluded 15 months after surgery. 3D image-based preselection of a proper aneurysm clip can be translated to the operating room and avoids intraoperative clip selection. The associated occlusion rate of aneurysms is high.