The ubiquitin-specific protease USP2a prevents endocytosis-mediated EGFR degradation.

Ubiquitination of epidermal growth factor receptor (EGFR) is required for downregulation of the receptor by endocytosis. Impairment of this pathway results in constitutively active EGFR, which is associated with carcinogenesis, particularly in lung cancer. We previously demonstrated that the deubiquitinating enzyme ubiquitin-specific protease 2a (USP2a) has oncogenic properties. Here, we show a new role for USP2a as a regulator of EGFR endocytosis. USP2a localizes to early endosomes and associates with EGFR, stabilizing the receptor, which retains active downstream signaling. HeLa cells transiently expressing catalytically active, but not mutant (MUT), USP2a show increased plasma membrane-localized EGFR, as well as decreased internalized and ubiquitinated EGFR. Conversely, USP2a silencing reverses this phenotype. Importantly, USP2a prevents the degradation of MUT in addition to wild-type EGFR. Finally, we observed that USP2a and EGFR proteins are coordinately overexpressed in non-small cell lung cancers. Taken together, our data indicate that USP2a antagonizes EGFR endocytosis and thus amplifies signaling activity from the receptor. Our findings suggest that regulation of deubiquitination could be exploited therapeutically in cancers overexpressing EGFR.

Transient contrast encephalopathy after carotid artery stenting.

PURPOSE: To report an unusual case of transient contrast encephalopathy arising after carotid artery stenting. CASE REPORT: An 82-year-old right-handed man with a recent history of transient ischemic events was admitted to the hospital for evaluation of carotid artery disease. During cerebral angiography, which identified a 90% right internal carotid artery stenosis, the patient received 25 mL of an ionic, low-osmolar contrast agent (ioxaglate) in each carotid artery. The following day he underwent successful carotid stenting, during which 180 mL of ioxaglate were used. He developed rapidly worsening confusion and left hemiparesis on the table. Noncontrast computed tomography showed marked cortical enhancement and edema of the right cerebral hemisphere in the distribution of the right anterior and middle cerebral arteries. The patient improved rapidly and by day 2 was completely recovered; magnetic resonance imaging documented no cortical edema and normal sulci. One month after the procedure, he was well, with patent carotid arteries. CONCLUSIONS: Transient neurotoxicity after carotid interventions must be differentiated from massive cerebral infarction and hyperperfusion syndrome, but the prognosis is excellent. However, subsequent contrast studies in a patient with this complication should be undertaken with extreme caution.

Effect of inhibition of MAO and COMT on intrarenal dopamine and serotonin and on renal function.

The purpose of the present investigation was to study the effects of inhibition of monoamine oxidase (MAO) and/or catechol-O-methyltransferase (COMT), enzymes involved in the degradation of dopamine (DA) and serotonin (5-HT), on intrarenal DA and 5-HT, as reflected in the renal interstitial fluid (RIF) microdialysate and urine, and on renal function. Inhibition of MAO selectively increased RIF 5-HT from 3.16 +/- 0.38 to 8.03 +/- 1.83 pg/min (n = 7, P < 0.05), concomitant with decreases in mean arterial blood pressure and glomerular filtration rate (2.09 +/- 0. 18 to 1.57 +/- 0.22 ml/min, n = 7, P < 0.05). Inhibition of COMT significantly increased RIF DA (3.47 +/- 0.70 to 8.68 +/- 1.96 pg/min, n = 9, P < 0.05), urinary DA (2.00 +/- 0.16 to 2.76 +/- 0.26 ng/min, n = 9, P < 0.05), and absolute excretion of sodium (6.42 +/- 2.00 to 9.82 +/- 1.62 micromol/min, n = 10, P < 0.05). Combined inhibition of MAO and COMT significantly increased RIF DA, urinary DA, and urinary 5-HT, which was accompanied with increases in urine flow rate, and absolute (3.03 +/- 0.59 to 8.40 +/- 1.61 micromol/min, n = 9, P < 0.01) and fractional excretion of sodium. We conclude that inhibition of MAO selectively increases RIF 5-HT. COMT appears to be more important than MAO in the metabolism of intrarenal DA. Physiological increases in intrarenal DA/5-HT induced by inhibition of their degrading enzymes are accompanied with significant alterations of renal function.

Glucose-derived 3'-(carboxymethyl)-3'-deoxyribonucleosides and 2', 3'-lactones as synthetic precursors for amide-linked oligonucleotide analogues.

Treatment of a 1,2-O-isopropylidene-3-ketopentofuranose derivative (obtained from D-glucose) with [(ethoxycarbonyl)methylene]triphenylphosphorane and catalytic hydrogenation of the resulting alkene gave stereodefined access to 3-(carboxymethyl)-3-deoxy-D-ribofuranose derivatives. Esters of 5-O-acetyl- or 5-azido-5-deoxy-3-(carboxymethyl)-D-ribofuranose were coupled with nucleobases to give branched-chain nucleoside derivatives. Ester saponification and protecting group manipulation provided 2'-O-(tert-butyldimethylsilyl) ethers of 5'-azido-5'-deoxy- or 5'-O-(dimethoxytrityl) derivatives of 3'-(carboxymethyl)-3'-deoxyribonucleosides that are effective precursors for synthesis of amide-linked oligoribonucleosides.

Object memory effects on figure assignment: conscious object recognition is not necessary or sufficient.

In three experiments we investigated whether conscious object recognition is necessary or sufficient for effects of object memories on figure assignment. In experiment 1, we examined a brain-damaged participant, AD, whose conscious object recognition is severely impaired. AD's responses about figure assignment do reveal effects from memories of object structure, indicating that conscious object recognition is not necessary for these effects, and identifying the figure-ground test employed here as a new implicit test of access to memories of object structure. In experiments 2 and 3, we tested a second brain-damaged participant, WG, for whom conscious object recognition was relatively spared. Nevertheless, effects from memories of object structure on figure assignment were not evident in WG's responses about figure assignment in experiment 2, indicating that conscious object recognition is not sufficient for effects of object memories on figure assignment. WG's performance sheds light on AD's performance, and has implications for the theoretical understanding of object memory effects on figure assignment.

Synthesis of amide-linked [(3')CH2CO-NH(5')] nucleoside analogues of small oligonucleotides.

We report syntheses of new amide-linked (di-penta)nucleoside analogues of antisense oligonucleotide components. Solution-phase coupling of 3'-(carboxymethyl)-3'-deoxy- and 5'-amino-5'-deoxynucleoside derivatives provides amide dimers. Activated [3'-(carboxymethyl)-3'-deoxy] units with a 5'-azido-5'-deoxy function provide "masked" 5'-amino-5'-deoxy residues for chain extension, and a 5'-O-DMT-protected unit provides the 5'-terminus for attachment to a phosphodiester linkage.

Opioid inhibition of formalin-induced changes in plasma extravasation and local blood flow in rats.

Hindpaw injection of dilute formalin produces brief (Phase 1) and persistent (Phase 2) nociceptive responses in the rat. We recently showed that systemically-administered remifentanil during Phase 1 interacted with peripheral opioid receptors to delay the onset and termination of Phase 2 (Taylor et al., 1997b). To test the hypothesis that opioid inhibition of proinflammatory events during Phase 1 contributed to this delay, we evaluated the effects of remifentanil on the time course of formalin-induced inflammation. We found that formalin increased paw thickness (edema), plasma extravasation and local blood flow within minutes of its injection, i.e. during Phase 1. Each of these responses was blocked during remifentanil administration (30 microg/kg i.v. bolus, followed 90 s later with a 15 microg/kg/min infusion for 13.5 min), indicating that opioids inhibit Phase 1 inflammation. Opioid blockade of the blood flow response could be reversed with a peripherally-acting opioid antagonist, naloxone methiodide, indicating that remifentanil acted upon peripheral opioid receptors. Although the administration of remifentanil during Phase 1 did not reduce the magnitude of inflammatory responses during Phase 2, it did delay the onset and termination of edema during Phase 2. As this corresponds to the effects of remifentanil on nociceptive responses during Phase 2, we suggest that opioid analgesics act upon peripheral sites to inhibit inflammation during Phase 1, leading to a delay in the temporal profile of inflammatory (and likely nociceptive) responses during Phase 2.

Multiplicative effects of intention on the perception of bistable apparent motion.

When viewing ambiguous displays, observers can, via intentional efforts, affect which perceptual interpretation they perceive. Specifically, observers can increase the probability of seeing the desired percept. Little is known, however, about how intentional efforts interact with sensory inputs in exerting their effects on perception. In two experiments, the current study explored the possibility that intentional efforts might operate by multiplicatively enhancing the stimulus-based activation of the desired perceptual representation. Such a possibility is suggested by recent neurophysiological research on attention. In support of this idea, when we presented bistable apparent motion displays under stimulus conditions differentially favoring one motion percept over the other, observers' intentional efforts to see a particular motion were generally more effective under conditions in which stimulus factors favored the intended motion percept.

Prospective, randomized trial of template-assisted versus undirected written recording of physician records in the emergency department.

STUDY OBJECTIVE: To determine whether use of the T-System (Emergency Services Consultants, Irving, TX) template-generated medical documentation system (1) decreases physician evaluation time in the emergency department, (2) increases gross billing under the 1997 Health Care Financing Administration guidelines by minimizing downcoding caused by inadequate documentation, and (3) increases physician satisfaction with the documentation process, compared with the undirected written narrative format. METHODS: A prospective, randomized, unblinded, controlled, convenience trial of documentation with the T-System of ED templates versus undirected written documentation was conducted in the ED of a county-owned, university-affiliated hospital. All patients seen between the hours of 7 AM and 10 PM during a 16-day period were included. The intervention was varying the method of documentation of the emergency physician. Adequacy of randomization to the 2 documentation groups was assessed by comparing ED triage classification, patient disposition, level of training of the evaluating physician, and whether ED consultation with other services occurred. Outcome measurements included emergency physician total evaluation and treatment time, professional bill, and satisfaction, as evaluated by a questionnaire completed after the study period. The 2 documentation groups were compared by an intention-to-treat analysis and by Student's t test and the median test as appropriate. RESULTS: A total of 1,228 patient encounters were included. Emergency physician total evaluation and treatment time with template-directed documentation was 4.6 minutes less than with undirected recording, a difference that was not significant (95% confidence interval [CI], -9.2 to 18.3). Gross billing was $29. 60 more per patient (95% CI, $22.20 to $37.00) with the T-System, as assessed by our hospital coders. This difference was caused by a mean.50 (95% CI,.39 to.60) higher level of evaluation and management coding. Physicians preferred the T-System (P <.0005). CONCLUSION: Use of template-assisted documentation in the ED was associated with higher gross billing and physician satisfaction but no significant decrease in emergency physician total evaluation time.