Aortic valve replacement after previous coronary artery bypass grafting

BACKGROUND: As the population ages, an increasing number of patients with previous coronary artery bypass grafting (CABG) will require subsequent aortic valve replacement (AVR). This study examined outcome of AVR after previous CABG and reviewed possible indications for valve replacement at the time of initial myocardial revascularization. METHODS: Between March 1975 and December 1994, 145 patients had AVR after previous CABG. Sixty-three patients (43%) had their initial CABG elsewhere. Reoperation for AVR was the second cardiac procedure in 137 patients and the third in 8. Redo CABG with AVR was done in 66 (46%). There were 118 men and 27 women. The mean age at CABG was 64 +/- 7.9 years; for AVR this was 71 +/- 7.6 years. RESULTS: In 2 young patients accelerated calcific aortic stenosis occurred in the setting of renal failure. Significant aortic stenosis did not appear to be addressed at initial CABG in 3 patients. Transaortic valvular gradient, as measured by cardiac catheterization, increased by 10.4 +/- 7.0 mm Hg/y. Twenty-four patients (16.6%) died. The mortality for AVR alone or for AVR + redo-CABG was 15 of 125 patients (12%). For patients having more complicated procedures, the mortality was 9 of 20 (45%). Nine patients (6.2%) suffered a postoperative cerebrovascular accident. Low preoperative ejection fraction measured by echocardiography, sternal reentry problems, complexity of operation, and prolonged cross-clamp and bypass times were significant factors associated with mortality. Age at AVR, interval between operations, the extent of underlying native coronary artery disease, the state of the previously placed bypass conduits, and methods of myocardial preservation were not significant predictors of operative mortality. On multivariate analysis there was only one significant value: prolonged cross-clamp time. CONCLUSIONS: Aortic valve replacement after previous CABG is associated with a mortality that is higher than that seen after repeat CABG or repeat AVR. It seems prudent, therefore, to use liberal criteria for AVR in those patients who require coronary revascularization and who, at the same time, have mild or moderate aortic valve disease.     

Posterior capsulorhexis with optic capture in pediatric cataract and intraocular lens surgery

To study brain regions involved in familiarity discrimination, rats were shown sets of novel and familiar objects. On each trial two objects were shown simultaneously to a rat so that one eye saw a novel object while the other saw a familiar object. Thus novel and familiar objects were seen with the same conditions of alertness and eye movements. Activated neurones were revealed by staining for products of the immediate early gene c-fos. Familiar stimuli activated significantly fewer neurones than novel stimuli in perirhinal cortex and area TE of temporal cortex, and the ventral lateral geniculate nucleus of the thalamus, but not in the hippocampus or other areas sampled. These findings are discussed in relation to recognition memory.     

Effect of commercial dilating agents on laser flare-cell measurements

OBJECTIVE: To compare the effect of tropicamide alone and tropicamide-phenylephrine on anterior chamber flare and cell measurements obtained with a laser flare-cell meter. DESIGN: Prospective study. SETTING: Gimbel Eye Centre, Calgary. SUBJECTS: Twenty white subjects (10 with blue irides and 10 with brown irides) aged 24 to 45 (mean 30.2) years without any known systemic or ocular disease. INTERVENTIONS: Laser flare-cell measurements were obtained 30 minutes after pupillary dilation with 1% tropicamide in one eye and a combination drop of 0.8% tropicamide and 5% phenylephrine in the other eye. The average of five readings was taken for each eye. OUTCOME MEASURES: Flare and cell measurements. RESULTS: There was no statistically significant difference in flare photon count or cell count between the eyes dilated with tropicamide and those dilated with tropicamide-phenylephrine. In addition, iris colour was not found to have a significant effect on flare and cell measurements. CONCLUSIONS: Our results suggest that pupillary dilation for laser flare-cell measurements can be done with either mydriatic agent in healthy white subjects of any eye colour without significant effects on the measurements. Further study is needed to determine whether the same is true in older subjects.     

A practice-based randomised controlled trial of the efficacy of an electric and a manual toothbrush on gingival health in patients with fixed orthodontic appliances

Twenty-three specimens from immediately anteroinferior to the mental foramen were obtained from male and female, dentate and edentate, human mandibles. Planoparallel 80 microm thick sections were prepared from the mandibular specimens and computerized quantitative microradiography undertaken, which allowed the production of mineralization frequency distribution curves and mean mineralization. No differences in mean mineralization with age, sex, presence or absence of dentition were found, but mineralization distribution curves indicated differences between males and females. Within the age range and small sample size examined (40-90 years) there were no age-related differences. There was a lower level of mineralization distribution in the edentulous than the dentate mandible.     

Serine protease of hepatitis C virus expressed in insect cells as the NS3/4A complex

Hepatitis C virus (HCV) protease NS3 and its protein activator NS4A participate in the processing of the viral polyprotein into its constituent nonstructural proteins. The NS3/4A complex is thus an attractive target for antiviral therapy against HCV. We expressed the full-length NS3 and NS4A in insect cells as a soluble fusion protein with an N-terminal polyhistidine tag and purified the two proteins to homogeneity. Cleavage at the junction between HisNS3 and NS4A occurs during expression, producing a noncovalent complex between HisNS3 and NS4A with a subnanomolar dissociation constant. We purified the HisNS3/4A complex by detergent extraction of cell lysate and by metal chelate chromatography. We removed the His tag by thrombin cleavage and then further purified the complex by gel filtration. The purified NS3/4A complex is active in a protease assay using a synthetic peptide substrate derived from the NS5A-NS5B junction, with kcat/K(m) of 3700 (+/- 600) M-1 s-1, an order of magnitude above those previously reported for NS3 expressed by other strategies. This high protease activity implies that the full-length sequences of NS3 and NS4A are required for optimal activity of the NS3 protease domain. We examined the dependence of the NS3/4A protease activity on buffer conditions, temperature, and the presence of detergents. We find that, under most conditions, NS3 protease activity is dependent on the aggregation state of the NS3/4A complex. The monodisperse, soluble form of the NS3/4A complex is associated with the highest protease activity.     

2-aminotetralin-derived substituted benzamides with mixed dopamine D2, D3, and serotonin 5-HT1A receptor binding properties: a novel class of potential atypical antipsychotic agents

A new chemical class of potential atypical antipsychotic agents, based on the pharmacological concept of mixed dopamine D2 receptor antagonism and serotonin 5-HT1A receptor agonism, was designed by combining the structural features of the 2-(N,N-di-n-propylamino)tetralins (DPATs) and the 2-pyrrolidinylmethyl-derived substituted benzamides in a structural hybrid. Thus, a series of 35 differently substituted 2-aminotetralin-derived substituted benzamides was synthesized and the compounds were evaluated for their ability to compete for [3H]-raclopride binding to cloned human dopamine D2A and D3 receptors, and for [3H]-8-OH-DPAT binding to rat serotonin 5-HT1A receptors in vitro. The lead compound of the series, 5-methoxy-2-[N-(2-benzamidoethyl)-N-n-propylamino]tetralin (12a), displayed high affinities for the dopamine D2A receptor (Ki = 3.2 nM), the dopamine D3 receptor (Ki = 0.58 nM) as well as the serotonin 5-HT1A receptor (Ki = 0.82 nM). The structure-affinity relationships of the series suggest that the 2-aminotetralin moieties of the compounds occupy the same binding sites as the DPATs in all three receptor subtypes. The benzamidoethyl side chain enhances the affinities of the compounds for all three receptor subtypes, presumably by occupying an accessory binding site. For the dopamine D2 and D3 receptors, this accessory binding site may be identical to the binding site of the 2-pyrrolidinylmethyl-derived substituted benzamides.     

Neurobehavioral effects from exposure to dental amalgam Hg(o): new distinctions between recent exposure and Hg body burden

Potential toxicity from exposure to mercury vapor (Hg(o)) from dental amalgam fillings is the subject of current public health debate in many countries. We evaluated potential central nervous system (CNS) toxicity associated with handling Hg-containing amalgam materials among dental personnel with very low levels of Hg(o) exposure (i.e., urinary Hg <4 microg/l), applying a neurobehavioral test battery to evaluate CNS functions in relation to both recent exposure and Hg body burden. New distinctions between subtle preclinical effects on symptoms, mood, motor function, and cognition were found associated with Hg body burden as compared with those associated with recent exposure. The pattern of results, comparable to findings previously reported among subjects with urinary Hg >50 microg/l, presents convincing new evidence of adverse behavioral effects associated with low Hg(o) exposures within the range of that received by the general population.