Biomedical subjects

Mark T Brown

Publications and source records attributed to Mark T Brown.

18 recordsLinked to original sources

PubMed2007

Draft genome sequence of the sexually transmitted pathogen Trichomonas vaginalis.

We describe the genome sequence of the protist Trichomonas vaginalis, a sexually transmitted human pathogen. Repeats and transposable elements comprise about two-thirds of the approximately 160-megabase genome, reflecting a recent massive expansion of genetic material. This expansion, in conjunction with the shaping of metabolic pathways that likely transpired through lateral gene transfer from bacteria, and amplification of specific gene families implicated in pathogenesis and phagocytosis of host proteins may exemplify adaptations of the parasite during its transition to a urogenital environment. The genome sequence predicts previously unknown functions for the hydrogenosome, which support a common evolutionary origin of this unusual organelle with mitochondria.

Animals↗

PubMed2006

Identification and biochemical characterization of serine hydroxymethyl transferase in the hydrogenosome of Trichomonas vaginalis.

Serine hydroxymethyl transferase (SHMT) is a pyridoxal phosphate (PLP)-dependent enzyme that catalyzes the reversible conversion of serine and tetrahydrofolate to glycine and methylenetetrahydrofolate. We have identified a single gene encoding SHMT in the genome of Trichomonas vaginalis, an amitochondriate, deep-branching unicellular protist. The protein possesses a putative N-terminal hydrogenosomal presequence and was shown to localize to hydrogensomes by immunofluorescence analysis, providing evidence of amino acid metabolism in this unusual organelle. In contrast to the tetrameric SHMT that exists in the mammalian host, we found that the T. vaginalis SHMT is a homodimer, as found in prokaryotes. All examined SHMT contain an 8-amino-acid conserved sequence, VTTTTHKT, containing the active-site lysyl residue (Lys 251 in TvSHMT) that forms an internal aldimine with PLP. We mutated this Lys residue to Arg and Gln and examined structural and catalytic properties of the wild-type and mutant enzymes in comparison to that reported for the mammalian protein. The oligomeric structure of the mutant K251R and K251Q TvSHMT was not affected, in contrast to that observed for comparable mutations in the mammalian enzyme. Likewise, contrary to that observed for mammalian SHMT, the catalytic activity of K251R TvSHMT was unaffected in the presence of PLP. The K251Q TvSHMT, however, was found to be inactive. These studies indicate that the active site of the parasite enzyme is distinct from its prokaryotic and eukaryotic counterparts and identify TvSHMT as a potential drug target.

Amino Acid Sequence↗

PubMed2006

Trichomonas vaginalis initiator binding protein (IBP39) and RNA polymerase II large subunit carboxy terminal domain interaction.

The core promoter that directs RNA polymerase to the start of transcription in the protist Trichomonas vaginalis is an initiator (Inr) element recognized by the Inr Binding Protein, IBP39. This nuclear protein is composed of two domains: a 14.5 kDa amino (N-terminal) and a 25 kDa carboxy terminal domain (C-domain). Here we describe the identification of an IBP39-interacting protein by screening a T. vaginalis expression library using a two-hybrid system with the IBP39 C-domain as bait. The CTD of the large subunit of RNAP II was found to specifically interact with the C-domain. The specificity and nature of the interaction between the CTD of RNAP II and the C-domain of IBP39 was validated by three independent biochemical methods: co-immunoprecipitation with epitope-tagged proteins, affinity chromatography and enzyme linked ligand sorbent (ELLSA) assays. Binding was shown to involve hydrophobic bonds and to have a disassociation constant (K(d)) of 690 nM (+/-55). These results confirm and extend our previous binding studies using a peptide composed of the last nine amino acids of RNAP II CTD [Schumacher MA, Lau AOT, Johnson PJ. Structural basis of core promoter recognition in a primitive eukaryote. Cell 2003;115:413-24] that predicted an interaction between the CTD and IBP39. These data further demonstrate that IBP39 minimally possesses two functional domains: a N-terminal DNA binding domain (that recognizes the Inr) [Liston DR, Johnson PJ. Analysis of a ubiquitous promoter element in a primitive eukaryote: early evolution of the initiator element. Mol Cell Biol 1999;19:2380-8] and a C-terminal protein binding domain that recognizes the RNAP II CTD, an interaction that may be critical for recruiting RNAP II for initiation of transcription.

Animals↗

PubMed2006

Microvascular reconstruction of cranial base defects: An evaluation of complication and survival rates to justify the use of this repair.

OBJECTIVES: To describe our experience, including selection criteria and complication rates, using microvascular free tissue transfer to repair large skull base defects and to determine if complication rate and posttreatment survival justify the use of this technique. DESIGN: Retrospective review of clinical cohort. SETTING: Tertiary care medical center. PATIENTS: A consecutive sample of patients undergoing ablative surgery with repair of cranial base defects with free tissue transfer from 1995 to 2004. All the patients' defects involved intracranial exposure. MAIN OUTCOME MEASURES: Rate of local and systemic complications, postoperative survival, and recurrence rate. RESULTS: The study population comprised 40 patients. Fifteen (38%) of the patients' defects were in the anterior cranial base, and 26 (65%) were in the middle cranial base. We used 5 types of free tissue flap, with a success rate of 95%. Our rate of perioperative mortality, meningitis, stroke, cerebrospinal fluid leak, epidural abscess, and osteomyelitis was 0%. We had 7 local complications and 4 systemic complications requiring increased length of hospital stay. Including microvascular problems, 12 patients had complications, for an overall complication rate of 30%. Follow-up ranged from 1 to 96 months, with a mean of 24 months. The tumor recurrence rate was 30%, and disease-specific survival was 81% at a mean 24-month follow-up. CONCLUSIONS: We did not experience any perioperative mortality or intracranial morbidity. Our low complication rate in combination with our tumor recurrence rate and rate of patient survival justify the use of free tissue transfer as an option in the closure of appropriate cranial base defects.

Adolescent↗

PubMed2006

Energy-based land use predictors of proximal factors and benthic diatom composition in Florida freshwater marshes.

The Landscape Development Intensity index (LDI), which is based on non-renewable energy use and integrates diverse land use activities, was compared to other measures of LU (e.g., %agriculture, %urban) to determine its ability for predicting benthic diatom composition in freshwater marshes of peninsular Florida. In this study, 70 small, isolated herbaceous marshes located along a human disturbance gradient (generally agricultural) throughout peninsular Florida were sampled for benthic diatoms and soil and water physical/chemical parameters (i.e., TP, TKN, pH, specific conductance, etc.). Landscape measures of percent agriculture, percent urban, percent natural, and LDI index values were calculated for a 100 m buffer around each site. The strongest relationships using Mantel's r statistic, which ranges from -1 to 1, were found between benthic diatom composition, the combined soil and water variables, and LDI scores (r=0.51, P<0.0001). Although similar, soil and water variables alone (r=0.45, P<0.0001) or with percent agriculture or percent natural were not as strongly correlated (both Mantel's r=0.46, P<0.0001). Little urban land use was found in the areas surrounding the study wetlands. Diatom data were clustered using flexible beta into 2 groups, and stepwise discriminant analysis identified specific conductance, followed by LDI score, soil pH, water total phosphorus, and ammonia, as cluster-separating variables. The LDI explained slightly more of the variation in species composition than either percent agriculture or percent natural, perhaps because the LDI can combine disparate land uses into a single quantitative value. However, the ecological significance of the difference between land use metrics and diatom composition is controvertible, and additional tests including more varied land uses appear warranted.

Diatoms↗

PubMed2006

A comparison of valdecoxib and naproxen in the treatment of rheumatoid arthritis symptoms.

OBJECTIVES: The primary aim of this work was to compare the efficacy of valdecoxib 10, 20, and 40 mg QD with that of placebo and naproxen 500 mg BID in patients with rheumatoid arthritis (RA). The overall safety and tolerability profiles of valdecoxib and naproxen were also compared. METHODS: A 12-week, multicenter, randomized, double-blind, parallel-group, placebo- and active-controlled study was performed in patients with adult-onset RA whose disease was in a flare state after discontinuing NSAIDs or other analgesics. Patients were randomly assigned to valdecoxib 10, 20, or 40 mg QD, naproxen 500 mg BID, or placebo. The primary efficacy measures were the American College of Rheumatology (ACR) 20% responder index (ACR-20), physicians' assessments of tender/painful joint count and swollen joint count, and patients' and physicians' global assessments of disease activity. Adverse events, clinical laboratory data, and vital signs were assessed by the investigator and compared between treatment groups to evaluate overall tolerability and safety. RESULTS: A total of 1093 patients were randomized to receive either valdecoxib 10 mg QD (n=226), valdecoxib 20 mg QD (n=219), valdecoxib 40 mg QD (n=209), naproxen 500 mg BID (n=219), or placebo (n=220). At all time points, the proportion of ACR-20 responders was significantly higher in the valdecoxib groups than the placebo group at weeks 2 (10 mg, P<0.001; 20 mg, P=0.008; 40 mg, P= 0.004), 6 (all, P<0.001), and 12 (10 mg, P=0.006; 20 mg, P=0.004; 40 mg, P<0.001). Similarly, at all time points, the proportion of ACR-20 responders was significantly higher in the naproxen 500-mg group than the placebo group (all time points, P<0.001). In addition, mean changes in the number of tender/painful joint counts were significantly greater in the valdecoxib groups than the placebo group at weeks 2 (all, P<0.001), 6 (10 mg, P=0.002; 20 and 40 mg, P<0.001), and 12 (10 mg, P=0.004; 20 mg, P= 0.012; 40 mg, P<0.001). Naproxen treatment was also associated with greater reductions in tender/painful joint count than placebo (all, P<0.001). Mean changes in swollen joint count decreased at all time points in all groups, with significantly greater changes in the valdecoxib and naproxen treatment groups than the placebo group (valdecoxib 20 and 40 mg: week 6, P= 0.014 and P=0.003, respectively; naproxen: week 2, P=0.014; week 6, P=0.015; week 12, P=0.030). Physicians' global assessments of disease activity scores were significantly lower in the valdecoxib (10 mg: weeks 2 and 6, P<0.001; week 12, P=0.001; 20 and 40 mg: all weeks, P<0.001) and naproxen (all time points, P<0.001) treatment groups than the placebo group. Adverse events were reported by 45.5% patients in the placebo group, 51.8% in the valdecoxib 10 mg QD group, 58.0% in the valdecoxib 20 mg QD group, 56.9% in the valdecoxib 40 mg QD group, and 62.6% in the naproxen 500 mg BID treatment group. CONCLUSIONS: Valdecoxib 10, 20, and 40 mg QD were efficacious for treating the signs and symptoms of RA in these patients. The efficacy of valdecoxib 20 and 40 mg QD was not significantly different from that of naproxen 500 mg BID. Valdecoxib was generally well tolerated in this study.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2006

Safety and efficacy of the cyclooxygenase-2 inhibitors parecoxib and valdecoxib after noncardiac surgery.

BACKGROUND: Valdecoxib and its intravenous prodrug parecoxib are reported to increase thromboembolic risk after coronary artery bypass grafting. The authors conducted a randomized trial to examine their safety and analgesic efficacy in patients recovering from major noncardiac surgical procedures. METHODS: The trial was randomized and double-blind, with 10 days of treatment and 30 days of follow-up. Patients (n = 1,062) received either parenteral parecoxib for 3 days and oral valdecoxib for the rest of the treatment period or placebo medications throughout. The frequency of predefined adjudicated postrandomization adverse events, including cardiovascular thromboembolism, renal dysfunction, gastroduodenal ulceration, and wound-healing complications, was assessed in each group. Secondary efficacy endpoints included patients' pain ratings, opioid analgesic consumption (recorded as morphine equivalents), and reports of opioid-related adverse effects. RESULTS: Predefined adjudicated adverse events had similar frequencies among patients who received parecoxib and valdecoxib (2.7%) and placebo patients (3.2%) (P = 0.58), including cardiovascular thromboembolic events (1.0% in each group; P = 1.0). Placebo patients consumed more morphine equivalents (66.2 +/- 92.4 mg) than did patients receiving parecoxib and valdecoxib (43.2 +/- 65.7 mg) (P < 0.001). Placebo patients had higher mean pain ratings on each of study days 2-10 (P < 0.01) and reported more opioid-related symptom distress on days 2-6 (P < 0.01). CONCLUSIONS: Parecoxib and valdecoxib are useful adjuncts to opioids for the treatment of postoperative pain in noncardiac surgical patients. Further study will be required to determine the safety profile of parecoxib and valdecoxib administered to patients with known atherosclerotic disease after noncardiac surgery.

Adult↗

PubMed2006

Proteins of the glycine decarboxylase complex in the hydrogenosome of Trichomonas vaginalis.

Trichomonas vaginalis is a unicellular eukaryote that lacks mitochondria and contains a specialized organelle, the hydrogenosome, involved in carbohydrate metabolism and iron-sulfur cluster assembly. We report the identification of two glycine cleavage H proteins and a dihydrolipoamide dehydrogenase (L protein) of the glycine decarboxylase complex in T. vaginalis with predicted N-terminal hydrogenosomal presequences. Immunofluorescence analyses reveal that both H and L proteins are localized in hydrogenosomes, providing the first evidence for amino acid metabolism in this organelle. All three proteins were expressed in Escherichia coli and purified to homogeneity. The experimental Km of L protein for the two H proteins were 2.6 microM and 3.7 microM, consistent with both H proteins serving as substrates of L protein. Analyses using purified hydrogenosomes showed that endogenous H proteins exist as monomers and endogenous L protein as a homodimer in their native states. Phylogenetic analyses of L proteins revealed that the T. vaginalis homologue shares a common ancestry with dihydrolipoamide dehydrogenases from the firmicute bacteria, indicating its acquisition via a horizontal gene transfer event independent of the origins of mitochondria and hydrogenosomes.

Amino Acid Sequence↗

PubMed2005

Complications of the COX-2 inhibitors parecoxib and valdecoxib after cardiac surgery.

BACKGROUND: Valdecoxib and its intravenous prodrug parecoxib are used to treat postoperative pain but may involve risk after coronary-artery bypass grafting (CABG). We conducted a randomized trial to assess the safety of these drugs after CABG. METHODS: In this randomized, double-blind study involving 10 days of treatment and 30 days of follow-up, 1671 patients were randomly assigned to receive intravenous parecoxib for at least 3 days, followed by oral valdecoxib through day 10; intravenous placebo followed by oral valdecoxib; or placebo for 10 days. All patients had access to standard opioid medications. The primary end point was the frequency of predefined adverse events, including cardiovascular events, renal failure or dysfunction, gastroduodenal ulceration, and wound-healing complications. RESULTS: As compared with the group given placebo alone, both the group given parecoxib and valdecoxib and the group given placebo and valdecoxib had a higher proportion of patients with at least one confirmed adverse event (7.4 percent in each of these two groups vs. 4.0 percent in the placebo group; risk ratio for each comparison, 1.9; 95 percent confidence interval, 1.1 to 3.2; P=0.02 for each comparison with the placebo group). In particular, cardiovascular events (including myocardial infarction, cardiac arrest, stroke, and pulmonary embolism) were more frequent among the patients given parecoxib and valdecoxib than among those given placebo (2.0 percent vs. 0.5 percent; risk ratio, 3.7; 95 percent confidence interval, 1.0 to 13.5; P=0.03). CONCLUSIONS: The use of parecoxib and valdecoxib after CABG was associated with an increased incidence of cardiovascular events, arousing serious concern about the use of these drugs in such circumstances.

Administration, Oral↗

PubMed2005

Landscape development intensity index.

The condition of landscapes and the ecological communities within them is strongly related to levels of human activity. Human-dominated land uses and especially the intensity of the uses can affect adjacent ecological communities through direct, secondary, and cumulative impacts. Using land use data and a development-intensity measure derived from energy use per unit area, an index of Landscape Development Intensity (LDI) can be calculated for watersheds of varying sizes to estimate the potential impacts from human-dominated activities that are experienced by ecological systems within those watersheds. The intended use of the LDI is as an index of the human disturbance gradient (the level of human induced impacts on the biological, chemical, and physical processes of surrounding lands or waters). The LDI can be used at the scale of river, stream, or lake watersheds or at the smaller scale of individual isolated wetland watersheds. Based on land uses and land cover, the LDI can be applied using available GIS land use/land cover data, aerial photographs, or field surveys. A description of data needs and methods for calculating an LDI index and several applications of the index as a land use based ranking scheme of the human disturbance gradient for watersheds are given.

Agriculture↗

PubMed2005

Valdecoxib for treatment of a single, acute, moderate to severe migraine headache.

OBJECTIVE: To evaluate the analgesic efficacy and safety of a single 20- or 40-mg dose of valdecoxib compared with placebo in treatment of a single, acute, moderate or severe migraine headache, with or without aura. BACKGROUND: Valdecoxib, an oral COX-2 specific inhibitor, is indicated for relief of the signs and symptoms of rheumatoid arthritis and osteoarthritis and treatment of primary dysmenorrhea. This study assessed the optimal dose of valdecoxib for treatment of a single, acute, moderate to severe migraine headache. METHODS: This was a double-blind, randomized, placebo- and active-controlled, multicenter, single-dose (primary end point) and multiple-dose (secondary end point), 56-day study of valdecoxib in the treatment of a single, acute, moderate or severe migraine headache, with or without aura. Migraine headaches were diagnosed according to International Headache Society (IHS) criteria. The primary efficacy end point was headache response (defined as reduction of headache pain intensity from moderate or severe to mild or none) at 2 hours postdose. Patients assessed their headache pain intensity and presence or absence of migraine-associated nausea, vomiting, phonophobia, and photophobia at intervals from 0 to 24 hours postdose. Sumatriptan 50 mg (encapsulated, in standard method, to maintain blinding) was included as a positive control for assay sensitivity. No statistical comparisons were performed between active treatment arms (valdecoxib 20 mg, valdecoxib 40 mg, and sumatriptan 50 mg). Adverse events and safety parameters were monitored throughout the study. RESULTS: In the intent-to-treat population of 570 patients (135 valdecoxib 20 mg, 151 valdecoxib 40 mg, 143 sumatriptan, and 141 placebo), no significant differences in baseline demographics among treatment groups were observed. The headache response rate with valdecoxib 40 mg and sumatriptan 50 mg was significantly greater than that with placebo at all time points from 2 to 24 hours postdose. With valdecoxib 20 mg, headache response rate was significantly greater than placebo from 2 to 4 hours. Significantly fewer patients treated with valdecoxib 40 mg, compared with placebo, experienced nausea, vomiting, and phonophobia at 2 hours postdose. CONCLUSIONS: A single 40-mg dose of valdecoxib is effective and well tolerated in treatment of migraine headache pain and associated symptoms.

Adolescent↗

PubMed2004

Interaction of actin and its 11-amino acid C-terminal peptide as cofactors with the adenovirus proteinase.

Actin bound to the adenovirus proteinase (AVP) with a lower equilibrium dissociation constant, 4.2 nM, than those exhibited by two viral, nuclear cofactors for AVP, the 11-amino acid peptide pVIc and the viral DNA. The k(cat)/K(m) ratio for substrate hydrolysis by AVP increased 150,000-fold in the presence of actin. The 11-amino acid residue peptide corresponding to the C-terminus of actin, which is highly homologous to pVIc, bound to AVP and stimulated its activity in the presence of DNA. As a cellular cofactor for AVP, AVP(actin) complexes may facilitate the cleavage of cytoskeletal proteins, preparing the infected cell for lysis and release of nascent virions.

Actins↗

PubMed2004

Ancient invasions: from endosymbionts to organelles.

The acquisitions of mitochondria and plastids were important events in the evolution of the eukaryotic cell, supplying it with compartmentalized bioenergetic and biosynthetic factories. Ancient invasions by eubacteria through symbiosis more than a billion years ago initiated these processes. Advances in geochemistry, molecular phylogeny, and cell biology have offered insight into complex molecular events that drove the evolution of endosymbionts into contemporary organelles. In losing their autonomy, endosymbionts lost the bulk of their genomes, necessitating the evolution of elaborate mechanisms for organelle biogenesis and metabolite exchange. In the process, symbionts acquired many host-derived properties, lost much of their eubacterial identity, and were transformed into extraordinarily diverse organelles that reveal complex histories that we are only beginning to decipher.

Alphaproteobacteria↗

PubMed2004

Effects of valdecoxib in the treatment of chronic low back pain: results of a randomized, placebo-controlled trial.

BACKGROUND: Valdecoxib, a cyclooxygenase (COX)-2 specific inhibitor, is indicated for relief of the signs and symptoms of rheumatoid arthritis, osteoarthritis, and primary dysmenorrhea. Therapeutic doses of COX-2 specific inhibitors are as effective as nonspecific nonsteroidal anti-inflammatory drugs in reducing inflammatory pain while sparing the gastrointestinal and platelet toxicity associated with nonspecific COX-1 inhibition. OBJECTIVE: The aim of this study was to assess the analgesic efficacy and tolerability of valdecoxib 40 mg/d compared with placebo in the treatment of chronic low back pain. METHODS: This 4-week, prospective, randomized, double-blind placebo-controlled, parallel-group study was conducted at 37 centers across the United States and 5 centers in Canada. Patients aged > or =18 years with chronic low back pain in flare were enrolled. Patients were randomized to receive valdecoxib 40-mg/d or placebo tablets, once daily for 4 weeks. Patients rated low back pain intensity on a visual analog scale and completed the Roland-Morris Disability Questionnaire and the modified Brief Pain Inventory-Short Form (mBPI-SF) at each visit. RESULTS: Two hundred ninety-three patients were enrolled. The valdecoxib group comprised 148 patients (81 women, 67 men; mean [SD] age, 48.6 [13.3] years; mean [SD] body weight, 86.6 [20.9] kg), and the placebo group included 145 patients (85 women, 60 men; mean [SD] age, 48.7 [12.6] years; mean [SD] body weight, 85.6 [19.9] kg). Of the enrolled patients, 249 completed the study: 134 patients (91%) who received valdecoxib and 115 patients (79%) who received placebo. No statistically significant differences in patient baseline characteristics were noted between treatment groups, except in response to 1 mBPI-SF question; patients in the valdecoxib group reported significantly greater interference in relations with other people due to pain than did those in the placebo group (P = 0.048). Changes from baseline in low back pain intensity were significantly greater in valdecoxib-treated patients at each assessment (all, P < 0.001 vs placebo). Pain scores on the mBPI-SF indicated significantly greater pain relief with valdecoxib at each assessment (all, P < or = 0.014 vs placebo). Improvements in mean Roland-Morris Disability Questionnaire score with valdecoxib were significantly greater than with placebo at each assessment (all, P < or = 0.003). Although the overall incidence of adverse events (AEs) was significantly higher among patients receiving valdecoxib than those receiving placebo (35.1% vs 24.1%, respectively; P = 0.042), no significant differences were found between groups for the incidence of any individual AE. Most AEs (89% [77/87 total events]) were mild or moderate in severity. CONCLUSIONS: In this study of patients with chronic low back pain, valdecoxib 40 mg/d provided rapid relief (within 1 week) and consistent relief (over 4 weeks). In addition, significant improvement in function and decreased disability were found with valdecoxib compared with placebo.

Adult↗

PubMed2004

The selective norepinephrine reuptake inhibitor antidepressant reboxetine: pharmacological and clinical profile.

Reboxetine is the first commercially available norepinephrine reuptake inhibitor developed specifically as a first line therapy for major depressive disorder. In vitro and in vivo pharmacological studies indicated that reboxetine methanesulphonate has high affinity and selectivity for the human norepinephrine transporter over the serotonin and dopamine transporters. Pharmacological specificity is further demonstrated by the absence of affinity for 45 transmitter receptors and CNS targets. Pharmacokinetic studies demonstrated that reboxetine is suitable for twice daily administration (8-10 mg/day) and that it exhibits minimal drug-drug interactions. The starting dose of reboxetine should be reduced in the elderly, in patients with renal or hepatic impairment, or in patients receiving potent CYP3A inhibitors. A total of 20 phase II/III clinical studies comprising placebo-controlled, active comparator-controlled and open-label uncontrolled studies in both short-term and long-term treatment of major depression have been conducted. In the treatment of major depression, reboxetine was superior to placebo in 5 of 12 short- or long-term placebo-controlled studies and was comparable in efficacy to active comparators in 3 out of 3 active-controlled studies. Unlike conventional tricyclic antidepressants (TCAs), reboxetine had only minimal sedative and cardiovascular liabilities, probably due to increased pharmacological specificity of reboxetine as compared with TCAs. Unlike serotonin reuptake inhibitors, this selective and specific norepinephrine reuptake inhibitor demonstrated a distinct side-effect profile with diminishing sexual dysfunction and GI side effects. The availability of this agent has afforded patients suffering from major depressive disorder a new class of agents to combat the debilitating consequence of this psychiatric disease. The demonstrated pharmacological specificity of this compound has provided the psychopharmacology community with a tool to elucidate the role of norepinephrine in brain functions. Testing this agent in different animal models has enabled the exploration of the role of modulation of norepinephrine tone in the therapy of CNS disorders beyond depression.

Adrenergic Uptake Inhibitors↗

PubMed2003

Lack of sexual dysfunction with the selective noradrenaline reuptake inhibitor reboxetine during treatment for major depressive disorder.

Sexual side-effects due to antidepressant treatment are an important consideration when selecting a treatment regimen and can influence patient compliance. Sexual function during treatment with the selective noradrenaline reuptake inhibitor reboxetine, the selective serotonin reuptake inhibitor (SSRI) fluoxetine and placebo has been assessed in a multicentre, randomized, 8-week, double-blind study of 450 patients diagnosed with major depressive disorder. Sexual function was measured by the Rush Sexual Inventory completed by male and female patients and administered at baseline, week 4 and week 8. The results indicate that reboxetine was similar to placebo and superior to fluoxetine in its effect on overall sexual function. There was a greater degree of sexual satisfaction in the reboxetine group compared to fluoxetine (P=0.02). The percentage of female patients able to achieve orgasm increased during the study period for women who received reboxetine and placebo, but decreased for those who received fluoxetine. These results suggest that reboxetine may be of particular benefit for patients at risk for sexual dysfunction with SSRIs.

Adolescent↗

PubMed2002

Actin can act as a cofactor for a viral proteinase in the cleavage of the cytoskeleton.

Cytoskeletal proteins are exploited by many viruses during infection. We report a novel finding that actin can act as a cofactor for the adenovirus proteinase (AVP) in the degradation of cytoskeletal proteins. Transfection studies in HeLa cells revealed AVP localized with cytokeratin 18, and this was followed by destruction of the cytokeratin network. For AVP to cleave cytokeratin 18, a cellular cofactor was shown to be required, consistent with AVP being synthesized as an inactive proteinase. Actin was considered a cellular cofactor for AVP, because the C terminus of actin is homologous to a viral cofactor for AVP. AVP was shown to bind to the C terminus of actin, and in doing so AVP exhibited full enzymatic activity. In vitro, actin was a cofactor in the cleavage of cytokeratin 18 by AVP. The proteinase alone could not cleave cytokeratin 18, but in the presence of actin, AVP cleaved cytokeratin 18. Indeed, actin itself was shown to be a cofactor and a substrate for its own destruction in that it was cleaved by AVP in vitro. Cleavage of cytoskeletal proteins weakens the structure of the cell, and therefore, actin as a cofactor may play a role in cell lysis and release of nascent virions.

Actins↗

PubMedDate not supplied

Analgesic efficacy of valdecoxib for acute postoperative pain after bunionectomy.

Two randomized, double-blind, placebo-controlled studies assessed the analgesic efficacy of valdecoxib in patients with moderate-to-severe pain after bunionectomy. Study 1 (N = 374) assessed the efficacy of two regimens of valdecoxib on the day after surgery (valdecoxib, 40 mg, with a 20-mg redose [n = 127]; valdecoxib, 40 mg, with a placebo redose [n = 122]; and placebo/placebo [n = 125]), and study 2 (N = 478) examined the efficacy of two different multiple-dose regimens on postoperative days 2 through 5 (valdecoxib, 20 mg, twice daily [n = 160]; valdecoxib, 20 mg, once daily [n = 159]; and placebo [n = 159]). Valdecoxib provided significant pain relief and reduced the use of opioid rescue medication. This efficacy was accompanied by improved global scores, decreased pain interference with function, and increased patient satisfaction.

Adolescent↗