POCSENSE: POCS-based reconstruction for sensitivity encoded magnetic resonance imaging

A novel method for iterative reconstruction of images from undersampled MRI data acquired by multiple receiver coil systems is presented. Based on Projection onto Convex Sets (POCS) formalism, the method for SENSitivity Encoded data reconstruction (POCSENSE) can be readily modified to include various linear and nonlinear reconstruction constraints. Such constraints may be beneficial for reconstructing highly and overcritically undersampled data sets to improve image quality. POCSENSE is conceptually simple and numerically efficient and can reconstruct images from data sampled on arbitrary k-space trajectories. The applicability of POCSENSE for image reconstruction with nonlinear constraining was demonstrated using a wide range of simulated and real MRI data.

Requirement for SAPK-JNK signaling in the induction of apoptosis by ribosomal stress in REH lymphoid leukemia cells

The present studies examined performance of SAPK cascades and apoptotic commitment following ribosomal trauma in REH lymphoid leukemia cells. Ribostatic insults included disruption of ribosomal activity by mechanistically dissimilar agents such as blasticidin-S (BCS) (which binds 28S-rRNA to block peptidyl bond formation), kasugamycin (KSM) (which binds 18S-rRNA to prevent translational initiation), and cycloheximide (CHX) (which blocks A-site to P-site translocation of peptidyl-tRNA). Exposure of REH cells to BCS elicited DNA degradation and apoptotic cytolysis. BCS stimulated JNK1/JNK2 and p38, and their shared targets c-Jun and ATF2. Inhibition of JNK1/JNK2 (but not of p38) antagonized blasticidin-induced apoptosis, whereas targeting alternative ribosomal sites with KSM or CHX limited translation, but failed to activate the SAPK cascade or initiate apoptosis. Our findings indicate that interference with 28S-rRNA by BCS initiates apoptosis in REH cells through recruitment of SAPK-JNK signaling. Disparities between the lethal actions of BCS, KSM, and CHX appear to reflect established differences in the subribosomal targets of these agents. We propose that the SAPK cascade comprises an essential mechanism for the transduction of specific lethal stress signals emanating from active ribosomes, and that interference with the 28S-rRNA, rather than the peptidyl transfer center of the large subunit, is critical to apoptotic commitment.

Influence of milk production potential on forage dry matter intake by multiparous and primiparous Brangus females

Brangus cows (n = 29) were used in three experiments to evaluate the effects of parity (multiparous vs. primiparous) and potential genetic merit for milk production (high vs. low) on forage intake during late gestation, early lactation, and late lactation. Cows were selected for milk production based on their sire's EPD for milk production (MEPD). Cows had ad libitum access to (130% of previous 2-d average intake) low-quality hay (5.3% CP and 76% NDF), and cottonseed meal was supplemented to ensure adequate degradable intake protein. All females were adapted to diets for at least 7 d, and individual intake data were collected for 9 d. During the lactation trials, actual milk production was determined using a portable milking machine following a 12-h separation from calves. During late gestation, multiparous cows consumed 24% more (P = 0.01) forage DM (kg/d) than primiparous cows; however, parity class did not influence forage intake when intake was expressed relative to BW. Furthermore, MEPD did not influence forage intake during late gestation. During early lactation, multiparous cows produced 66% more (P < 0.001) milk than primiparous cows, and high MEPD tended (P = 0.10) to produce more milk than low MEPD. Multiparous cows consumed 19% more (P < 0.0001) forage DM than did primiparous cows when expressed on an absolute basis, but not when expressed on a BW basis. High-MEPD cows consumed 8% more (P < 0.05) forage DM than did low-MEPD cows. During late lactation, multiparous cows produced 84% more milk than primiparous cows, although MEPD did not influence (P = 0.40) milk yield. In addition, multiparous cows consumed 17% more (P < 0.01) forage DM per day than primiparous cows, but when intake was expressed relative to BW, neither parity nor MEPD influenced forage DMI during late lactation. Milk yield and BW explained significant proportions of the variation in forage DMI during early and late lactation. Each kilogram increase in milk yield was associated with a 0.33- and 0.37-kg increase in forage DMI for early and late lactation, respectively. Results suggest that multiand primiparous cows consume similar amounts of low-quality forage DM, expressed per unit of BW, during late gestation and lactation. Selecting beef cows for increased genetic merit for milk production increases forage DMI during early lactation.

Vagus nerve stimulation (VNS) for treatment-resistant depression: efficacy, side effects, and predictors of outcome

This open pilot study of vagus nerve stimulation (VNS) in 60 patients with treatment-resistant major depressive episodes (MDEs) aimed to: 1) define the response rate; 2) determine the profile of side effects; and, most importantly; 3) establish predictors of clinical outcome. Participants were outpatients with nonatypical, nonpsychotic, major depressive or bipolar disorder who had not responded to at least two medication trials from different antidepressant classes in the current MDE. While on stable medication regimens, the patients completed a baseline period followed by device implantation. A 2-week, single blind, recovery period (no stimulation) was followed by 10 weeks of VNS. Of 59 completers (one patient improved during the recovery period), the response rate was 30.5% for the primary HRSD(28) measure, 34.0% for the Montgomery-Asberg Depression Rating Scale (MADRAS), and 37.3% for the Clinical Global Impression-Improvement Score (CGI-I of 1 or 2). The most common side effect was voice alteration or hoarseness, 55.0% (33/60), which was generally mild and related to output current intensity. History of treatment resistance was predictive of VNS outcome. Patients who had never received ECT (lifetime) were 3.9 times more likely to respond. Of the 13 patients who had not responded to more than seven adequate antidepressant trials in the current MDE, none responded, compared to 39.1% of the remaining 46 patients (p =.0057). Thus, VNS appears to be most effective in patients with low to moderate, but not extreme, antidepressant resistance. Evidence concerning VNS' long-term therapeutic benefits and tolerability will be critical in determining its role in treatment-resistant depression.

Colloid mobilization in the field using citrate to remediate chromium

We investigated the feasibility of cleaning aquifer sediments, long contaminated with chromium (Cr) from a metal plating facility, by detaching colloid-sized sorbents from the immobile aquifer solids and then pumping those colloids to the surface for treatment. In laboratory experiments using aquifer solids from the site, several solutions (water at various pHs, phosphate, oxalate, ascorbate, citrate) were examined for their ability to disperse colloids and Cr. Based on these tests, a 5 mM citrate solution at pH 7 was selected. Subsequently, such a citrate solution was used in the field in two single-well injection-withdrawal experiments. Large quantities of colloids were released immediately after injection. The colloidal particles mobilized by citrate in the field had more than 20 times higher Cr concentrations than did the average aquifer sediments, implying success in mobilizing Cr-associated phases. Further, laboratory and field tests showed that anion exchange of citrate for chromate caused some additional release of Cr from these aquifer solids.

Effects of nitrogen fertilization and harvest date on yield, digestibility, fiber, and protein fractions of tropical grasses

To evaluate the response of three tropical forage species to varying rates of nitrogen (N) fertilization [0, 39, 78, 118, 157 kg of N/(ha x cutting)] and five summer harvests, forage DM mass and nutritive value were evaluated in a randomized complete block design with a split-split plot arrangement of treatments. Plots (n = 60) were established in 1996, and five harvests were conducted every 28 d from June through September in 1997 and 1998, with fertilizer applications occuring after each harvest. Fertilization with 78 kg of N/(ha x cutting) increased forage mass in these grasses by 129% (P < 0.01) compared with no N fertilization. Additional N did not result in further increases of forage mass. Bermudagrass (Cynodon dactylon) produced more forage DM [P < 0.01; 1,536 +/- 43 kg/(ha x cutting)] than stargrass [Cynodon nlemfuensis; 1,403 +/- 43 kg/(ha x cutting)] or bahiagrass [Paspalum notatum; 1,297 +/- 43 kg/(ha x cutting)]. Peak forage mass for all species occurred in late June and July. In vitro organic matter digestibility (IVOMD) of stargrass increased (P < 0.01) linearly with fertilization. A quadratic response to N fertilization (P < 0.01) was noted in IVOMD of bermudagrass, whereas bahiagrass was not affected. Bermudagrass was more (P < 0.01) digestible (57.5 +/- 0.4) than stargrass (54.6 +/- 0.4) and bahiagrass (51.9 +/- 0.4%). As fertilization level increased, NDF decreased linearly (P < 0.01) in all three forages. Total N concentration increased (P < 0.01) linearly as N fertilization increased in all forages. Total N concentration was highest (P < 0.01) in stargrass (2.4%, DM basis) compared with bermudagrass (2.2%) and bahiagrass (2.0%). Total N concentration was depressed in all forages for late June and July harvests (P < 0.01). Fertilization increased (P < 0.05) the concentration (% of DM) of all protein fractions. In July and August, nonprotein N was reduced 11.8% (P < 0.01), whereas ADIN increased in July (P < 0.01). Bahiagrass had less N in cell contents than did bermudagrass and stargrass but had a greater concentration of N associated with the cell wall. Managerial factors, including rates of N fertilization and harvest dates, can have profound effects on the nutritional value of forage. An increased understanding of these effects is imperative to improve supplementation programs for ruminants.

Attentional processes in autism

Attentional processes in individuals with high-functioning autism were compared with a matched control group. Participants for the study were 103 children and adults with autism and 103 control subjects. Measures administered corresponded to Mirsky et al.'s (1991) factor analysis of tests of attention. Diminished performance was noted on measures that loaded on the Focus-Execute and Shift factors, but not on the Sustain and Encode factors. For tests in which psychomotor speed was used as the score, and the difference between groups was significant, covariance analyses were performed, using tests of basic motor functions as covariates. This procedure led to attenuation to the point of nonsignificant differences in the case of some of the attention tests. Thus, this comprehensive analysis of attention in individuals with high-functioning autism only found differences on measures in which the task placed demands on cognitive flexibility or psychomotor speed. Thus, purported attention deficits in autism may actually be primary deficits in complex decision making or psychomotor abilities.

An efficient synthesis of 3-hetero-13,14-dihydro prostaglandin F1alpha analogues

[structure: see text]. A new class of 3-hetero-13,14-dihydro prostaglandin F(1)(alpha) analogues was synthesized from a common intermediate. The latter was constructed via a two-step, three-component process. The lower chain, containing the 15-(phenoxymethyl) group, was synthesized in enantiopure form using Jacobsen's (salen)Co-catalyzed kinetic resolution of a terminal epoxide with phenol.

Generation and characterization of a PhoP homologue mutant of Neisseria meningitidis

Two-component regulatory systems are important regulators of virulence genes in a number of bacteria. Genes encoding a two-component regulator system, with homology to the phoP/phoQ system in salmonella, were identified in the meningococcal genome. Allele replacement was used to generate a meningococcal knock-out mutant of the regulator component of this system, and its phenotype was examined. The mutant displayed many differences in protein profiles compared with wild type, consistent with it being a gene-regulatory mutation. Many of the growth characteristics of the mutant were similar to those of phoP mutants of salmonella: it was unable to grow at low concentrations of magnesium and was sensitive to defensins and other environmental stresses. Magnesium-regulated differences in protein expression were abrogated in the mutant, indicating that the meningococcal PhoP/PhoQ system may, as in salmonella, respond to changes in environmental magnesium levels. These results are consistent with the PhoP homologue playing a similar role in the meningococcus to PhoP in salmonella and suggest that it may similarly be involved in the regulation of virulence genes in response to environmental stimuli in the meningococcus. In support of this conclusion, we found the mutant grew was unable to grow in mouse serum and was attenuated in its ability to traverse through a layer of human epithelial cells. Identification of those genes regulated by the meningococcal PhoP may provide a route towards the identification of virulence genes in the meningococcus.

Advances in radiotherapy for carcinoma of the head and neck

Increasingly, progress in the radiotherapy of carcinomas of the head and neck is being driven by principles of radiobiology. This article discusses some of the major advances in head and neck radiotherapy, including altered fractionation, concomitant chemotherapy, and intensity-modulated radiotherapy, in the context of radiobiologic rationale, potential impact on tumor control, and normal tissue complications.

Efficacy of methylphenidate among children with autism and symptoms of attention-deficit hyperactivity disorder

Thirteen children (ages 5.6 to 11.2 years) with autism and symptoms of attention-deficit hyperactivity disorder (ADHD) participated in a double-blind, placebo-controlled crossover study of methylphenidate (0.3 and 0.6 mg/kg per dose). Eight subjects responded positively, based upon a minimum 50% decrease on the Conners Hyperactivity Index. Ratings of stereotypy and inappropriate speech, which are often associated with autistic core features, also decreased. However, no changes were found on the Child Autism Rating Scale, a global assessment of autistic symptomotology. Significant adverse side effects occurred in some children including social withdrawal and irritability, especially at the 0.6 mg/kg dose. Results suggest that methylphenidate can be efficacious for children with autism and ADHD symptoms. However, this group of children seems to be particularly susceptible to adverse side effects.

Poliovirus induces an early impairment of mitochondrial function by inhibiting succinate dehydrogenase activity

Poliovirus infection of COS-1 and T47D cells caused a rapid decrease in total cell respiration, and this was attributed to an inhibition of mitochondrial respiration. The stimulation of mitochondrial respiration by pyruvate plus malate or succinate was impaired in saponin-permeabilised cells. However, this inhibition could be overcome by the addition of N,N,N',N'-tetramethyl-1, 4-phenylenediamine and ascorbate. The activity of succinate dehydrogenase was impaired in parallel with the inhibition of mitochondrial respiration during poliovirus infection. This shows that mitochondrial function is profoundly altered during poliovirus infection and that this occurs primarily through inhibition of electron flow at complex II of the mitochondrial respiratory chain.

Synthesis of unnatural amino acids via Suzuki cross-coupling of enantiopure vinyloxazolidine derivatives

[formula: see text] (R and S)-alpha-Amino alcohols and alpha-amino acids, including 4-methoxyhomophenylalanine, with a variety of unnatural side chains have been synthesized via palladium-catalyzed cross-coupling Suzuki reactions. The key building blocks 1 and 2, synthesized from the common achiral precursor 2-butene-1,4-diol, were made enantiopure utilizing a Pseudomonas cepacia lipase-catalyzed kinetic resolution. The optimal conditions for the Suzuki cross-coupling and the subsequent oxidations of the resultant alpha-amino alcohols are described.

Long-bone fractures in llamas: six cases (1993-1998)

OBJECTIVE

To determine clinical and radiographic findings, treatment, and outcome for llamas with long-bone fractures.

DESIGN

Retrospective study.

ANIMALS

6 llamas.

PROCEDURE

Medical records of llamas admitted between 1993 and 1998 because of long-bone fractures were reviewed. Data collected included age, sex, type of fracture, method of fracture repair, and postoperative complications. The Fisher exact test was used to compare age and sex of the llamas with long-bone fractures with those of the hospital population of llamas. All owners were contacted by telephone to determine perceived postoperative problems and whether the llamas were able to perform as expected.

RESULTS

Mean age was 160.8 days (range, 23 to 365 days). There was 1 male and 5 females. Fractures were more likely to occur in young llamas (< or = 1 year old) than in adults. Five of the fractures were attributed to traumatic episodes. Long bones affected included the tibia (n = 2), radius (2), femur (1), and humerus (1). Internal fixation with lag screws, plating, or both was performed on fractures of all llamas except 1; that llama was treated by use of confinement to a stall. None of the llamas had intraoperative complications, but postoperative complications were reported in 2 llamas. All fractures healed eventually, and clients were pleased with outcomes.

CONCLUSIONS AND CLINICAL RELEVANCE

Long-bone fractures in llamas are uncommon. Several types of long bone fractures can be successfully repaired by use of internal fixation, resulting in few complications and minimal convalescent time.

Inhibition of settlement and metamorphosis of the ascidian Herdmania curvata by non-geniculate coralline algae

The surfaces of non-geniculate coralline algae (NCA) are known to induce the settlement and metamorphosis of disparate marine taxa. In this study we investigate the responsiveness of larvae of Herdmania curvata (Ascidiacea: Stolidobranchia) to three species of NCA (Neogoniolithon brassica-florida, Hydrolithon onkodes, and Lithothamnium prolifer) that cohabit the slope and crest of Heron Reef, Great Barrier Reef. H. curvata larvae were first exposed to these NCA at or within 2 h of hatching, which is 1 to 2 h prior to attaining competence, and then cultured continuously with the NCA for 12 to 14 h. Rates of settlement and metamorphosis of H. curvata cultured in laboratory chambers in the presence of the different NCA were significantly lower than spontaneous rates in seawater. The limited settlement in treatments containing NCA were confined entirely to the chamber periphery, and settlement never occurred on the surface of the NCA. The inhibitory effect was dose-dependent and was stronger in N. brassica-florida and H. onkodes than in L. prolifer. Larvae that did not settle in treatments with NCA had rounded anterior trunks and, in extreme cases, kinked tails with rounded and dissociated tail muscle cells. In some individuals, we observed the anterior chemosensory papillae being sloughed off the larval body. Morphological analysis of trunk ectodermal and mesenchymal nuclei of larvae cultured in the presence of the NCA revealed that general necrotic cell death was occurring. Importantly, H. curvata larvae that were exposed to NCA could not subsequently be induced to metamorphose in KCl-elevated seawater, whereas larvae not exposed to NCA metamorphosed at high rates in KCl-elevated seawater.

Induction of apoptosis in U937 human leukemia cells by suberoylanilide hydroxamic acid (SAHA) proceeds through pathways that are regulated by Bcl-2/Bcl-XL, c-Jun, and p21CIP1, but independent of p53

Determinants of differentiation and apoptosis in myelomonocytic leukemia cells (U937) exposed to the novel hybrid polar compound SAHA (suberoylanilide hydroxamic acid) have been examined. In contrast to hexamethylenbisacetamide (HMBA), SAHA-related maturation was limited and accompanied by marked cytoxicity. SAHA-mediated apoptosis occurred within the G0G1 and S phase populations, and was associated with decreased mitochondrial membrane potential, caspase-3 activation, PARP degradation, hypophosphorylation/cleavage of pRB, and down-regulation of c-Myc, c-Myb, and B-Myb. Enforced expression of Bcl-2 or Bcl-XL inhibited SAHA-induced apoptosis, but only modestly potentiated differentiation. While SAHA induced the cyclin-dependent kinase inhibitor p21CIP1, antisense ablation of this CDKI increased, rather than decreased, SAHA-related lethality. In contrast, conditional expression of wild-type p53 failed to modify SAHA actions, but markedly potentiated HMBA-induced apoptosis. Finally, SAHA modestly increased expression/activation of the stress-activated protein kinase (SAPK/JNK); moreover, SAHA-related lethality was partially attenuated by a dominant-negative c-Jun mutant protein (TAM67). SAHA did not stimulate mitogen-activated protein kinase (MAPK), nor was lethality diminished by the specific MEK/MAPK inhibitor PD98059. These findings indicate that SAHA potently induces apoptosis in human leukemia cells via a pathway that is p53-independent but at least partially regulated by Bcl-2/Bcl-XL, p21CIP1, and the c-Jun/AP-1 signaling cascade.

Evidence that the apoptotic actions of etoposide are independent of c-Jun/activating protein-1-mediated transregulation

We recently demonstrated that physiological induction of apoptosis by cytotoxic sphingolipid messengers proceeds via activating protein-1 (AP1)-dependent and AP1-independent mechanisms in U937 human monoblastic leukemia cells. Here we examine involvement of the stress-activated protein kinase (SAPK) cascade and AP1 in the initiation of apoptosis in U937 cells by podophyllotoxin-derived inhibitors of topoisomerase II. Induction of apoptotic cell death and DNA damage by treatment of U937 cells with etoposide (100 microM) was associated with phosphorylation and activation of the c-Jun NH(2)-terminal kinase (JNK1) SAPK enzymes p46 and p54-JNK2 and transient increases in expression of the transcription factor c-Jun, a primary JNK substrate. These responses were accompanied by a modest, but sustained, recruitment of the mitogen-activated protein kinases p42-extracellular signal receptor-activated kinase (ERK)1 and p44-extracellular signal receptor-activated kinase 2. The capacity of etoposide to promote double-stranded DNA degradation and cell death was unaffected by manipulations that interfere with SAPK signaling outflow through c-Jun/AP1, including: 1) pharmacological inhibition of AP1 activity by diferuloylmethane and 2) molecular ablation of normal c-Jun function by the Jun dominant-negative mutant TAM-67. Cytotoxicity of the structurally related compound teniposide was similarly unaffected. In parallel trials, the lethal actions of ceramide (but not of sphingosine) were markedly diminished by pretreatment with diferuloylmethane or expression of TAM-67, confirming the effectiveness of these interventions in suppression of SAPK/AP1-dependent apoptosis. The involvement of AP1 in the proapoptotic actions of other inhibitors of topoisomerase II activity was also evaluated. Induction of cell death by the anthracyclines daunorubicin, daunorubicin, and idarubicin was found to be insensitive to pretreatment with diferuloylmethane or expression of TAM-67. Collectively, the present data indicate that induction of apoptosis by etoposide and related inhibitors of topoisomerase II is mediated through a cell death pathway that does not require SAPK-dependent recruitment of AP1. These findings additionally suggest that activation of the SAPK represents a consequence, rather than an underlying cause, of etoposide-induced apoptosis in myeloid leukemia cells.

Exercise programs for fitness and health for geriatrics

"As a consequence of diminished exercise tolerance, a large and increasing number of elderly people will be living below, at, or just above 'thresholds' of physical ability, needing only minor intercurrent illness to render them completely dependent" (Astrand, 1992, p. 1231S). The NP can play a crucial role in educating motivating, and encouraging geriatric clients to continue or initiate a fitness program. The exercise program that is prescribed by NPs for their patients "depends on their needs, goals, physical and health status, personal preference, and available time, equipment, and facilities" (Pollack et al., 1994, p. 588). Fitness is a goal for all geriatric patients, that they might remain healthy and physically fit longer, and therefore continue to lead active, fulfilling lives.

Effect of nitrogen and phosphorus addition on phenanthrene biodegradation in four soils

Phenanthrene mineralization rates were found to vary widely among four soils; differences in soil nutrient levels was one hypothesis to explain this variation. To test this hypothesis, phenanthrene mineralization rates were measured in these soils with, and without, added nitrogen and phosphorus. Mineralization rates either remained unchanged or were depressed by the addition of nitrogen and phosphorus. Phenanthrene degradation rates remained unchanged in the soil which had the highest indigenous levels of nitrogen and phosphorus and which showed the largest increase in phosphorus levels after nutrients were added. The soils in which degradation rates were depressed had lower initial phosphorus concentrations and showed much smaller or no measurable increase in phosphorus levels after nutrients were added to the soils. To understand the response of phenanthrene degradation rates to added nitrogen and phosphorus, it may be necessary to consider the bioavailability of added nutrients and nutrient induced changes in microbial metabolism and ecology.

A novel hydroxamic acid compound, BMD188, demonstrates anti-prostate cancer effects by inducing apoptosis. II: In vivo efficacy and pharmacokinetic studies

BACKGROUND

In the preceding paper, we demonstrated that, BMD188 [cis-1-hydroxy-4-(1-naphthyl)-6-octylpiperidine-2-one], a newly synthesized cyclic hydroxamic acid compound, induces potent apoptotic death of prostate cancer cells in vitro. In this project, we studied the in vivo pharmacokinetic behavior and anti-tumor efficacy of this novel compound.

MATERIALS AND METHODS

A bioavailability/elimination study was first performed using radiolabeled BMD188 administered to rats through intraperitoneal (i.p.), intravenous (i.v). or oral (p.o.) routes. Based on these pharmacokinetic data as well as pilot experiments on in vivo toxicity, two sets of efficacy studies, with i.p. administered BMD188, were performed in SCID mice or athymic nude mice which had been orthotopically transplanted with Du145 human prostate cancer cells. Tumor growth rate was measured and the final tumor weights and sizes determined. Subsequently, histopathological data were obtained and tumor tissue sections were used for apoptosis (i.e., TUNEL) staining.

RESULTS

The pharmacokinetic studies revealed low (approximately 8%) absorption through the p.o. route and high (approximately 70%) absorption through the i.p. route. The average plasma half life (T1/2) of BMD188 was approximately 50 h. Post-absorption, plasma elimination of radioactivity was similar to that in animals given [3H]-188 intravenously. The in vivo efficacy results indicate that i.p. administered BMD188 significantly inhibited the primary growth and local invasion of Du145 prostate cancer cells orthotopically implanted into SCID or athymic nude mice. The tumor-inhibitory effect of BMD188 was due to apoptosis induction in vivo, as revealed by histological analysis as well as TUNEL staining of the tumor tissue sections.

CONCLUSION

Collectively, the preceding in vitro and the current in vivo studies suggest that BMD188 and its analogs may find clinical applications in the treatment of prostate cancer patients by inducing apoptotic death of prostate cancer cells.

The world wide web: exploring a new advertising environment

The World Wide Web currently boasts millions of users in the United States alone and is likely to continue to expand both as a marketplace and as an advertising environment. Three experiments explored advertising in the Web environment, in particular memory for ads as they appear in everyday use across the Web. Experiments 1 and 2 examined the effect of advertising repetition on the retention of familiar and less familiar brand names, respectively. Experiment 1 demonstrated that repetition of a banner ad within multiple web pages can improve recall of familiar brand names, and Experiment 2 demonstrated that repetition can improve recognition of less familiar brand names. Experiment 3 directly compared the retention of familiar and less familiar brand names that were promoted by static and dynamic ads and demonstrated that the use of dynamic advertising can increase brand name recall, though only for familiar brand names. This study also demonstrated that, in the Web environment, much as in other advertising environments, familiar brand names possess a mnemonic advantage not possessed by less familiar brand names. Finally, data regarding Web usage gathered from all experiments confirm reports that Web usage among males tends to exceed that among females.

Adaptive local regularization methods for the inverse ECG problem

One of the fundamental problems in theoretical electrocardiography can be characterized by an inverse problem. We present new methods for achieving better estimates of heart surface potential distributions in terms of torso potentials through an inverse procedure. First, we outline an automatic adaptive refinement algorithm that minimizes the spatial discretization error in the transfer matrix, increasing the accuracy of the inverse solution. Second, we introduce a new local regularization procedure, which works by partitioning the global transfer matrix into sub-matrices, allowing for varying amounts of smoothing. Each submatrix represents a region within the underlying geometric model in which regularization can be specifically 'tuned' using an a priori scheme based on the L-curve method. This local regularization method can provide a substantial increase in accuracy compared to global regularization schemes. Within this context of local regularization, we show that a generalized version of the singular value decomposition (GSVD) can further improve the accuracy of ECG inverse solutions compared to standard SVD and Tikhonov approaches. We conclude with specific examples of these techniques using geometric models of the human thorax derived from MRI data.

Effects of adenosine 5'-triphosphate, uridine 5'-triphosphate, adenosine 5'-tetraphosphate and diadenosine polyphosphates in guinea-pig taenia caeci and rat colon muscularis mucosae

The functional effects of adenosine 5'-triphosphate (ATP), uridine 5'-triphosphate (UTP), adenosine 5'-tetraphosphate (AP4) and the diadenosine polyphosphates P1,P3-diadenosine triphosphate (Ap3A), P1,P4-diadenosine tetraphosphate (Ap4A) and P1,P5-diadenosine pentaphosphate (Ap5A) were studied in two isolated smooth muscle preparations thought to contain P2Y (P2Y1) receptors, the guinea-pig taenia caeci (which relaxes to ATP) and the rat colon muscularis mucosae (which contracts to ATP). In addition, the breakdown of these compounds by the rat colon muscularis mucosae was investigated by high pressure liquid chromatography. In the guinea-pig taenia caeci all the purine nucleotides caused relaxation with a potency order of Ap3A=Ap4A> ATP>AP4=Ap5A, and these relaxations were antagonised by suramin with apparent pA2 values in the region of 5, consistent with activation of a P2Y1 receptor. In the rat colon muscularis mucosae the nucleotides caused contraction with a potency order of Ap3A = Ap4A>ATP=AP4 =Ap5A >UTP. However, while suramin (100 microM) inhibited responses to ATP and UTP at all concentrations of agonist, it only inhibited contractions induced by the higher concentrations of AP4, Ap3A and Ap4A and had little effect on contractions induced by Ap5A. A higher concentration of suramin (1 mM) enhanced contractions induced by ATP but greatly inhibited those induced by UTP and had no effect on responses to the other agonists. The A1 adenosine receptor antagonist 1,3-dipropyl-8-cyclopentylxanthine (DPCPX; 10 nM) had no effect on responses to ATP or UTP but inhibited responses to Ap3A, Ap4A, Ap5A and AP4. A combination of suramin (1 mM) and DPCPX (10 nM) almost abolished responses to all the agonists. ATP and UTP were rapidly degraded by the rat colon muscularis mucosae while AP4, Ap3A, Ap4A and Ap5A were degraded more slowly, and the major product detected after breakdown of the purine nucleotides was inosine rather than adenosine. The breakdown of all the nucleotides was inhibited by suramin (1 mM), although this inhibition did not achieve statistical significance in the case of ATP. These results show that while the diadenosine polyphosphates appear to act as P2 agonists in the taenia caeci, in the rat colon muscularis mucosae their major action is via adenosine A1 receptors rather than via P2 receptors. In addition, although they are more stable than ATP or UTP, their action in this tissue is clearly affected by their degradation which complicates the effects of suramin.

New cyclooxygenase-2/5-lipoxygenase inhibitors. 2. 7-tert-butyl-2,3-dihydro-3,3-dimethylbenzofuran derivatives as gastrointestinal safe antiinflammatory and analgesic agents: variations of the dihydrobenzofuran ring

A series of 5-keto-substituted 7-tert-buty1-2,3-dihydro-3,3- dimethylbenzofurans (DHDMBFs) were found to be nonsteroidal antiinflammatory and analgesic agents. These compounds are inhibitors of 5-lipoxygenase (5-LOX) and cyclooxygenase (COX) with selectivity for the COX-2 isoform. A series of analogues were prepared to investigate the scope of this lead. Five ketone side chains from active DHDMBFs were used to investigate the effects of changes in the DHDMBF "core": the size and identity of the heterocycle and the substituent requirements of the heterocycle and phenyl ring. Biological testing showed that a variety of structural changes can be accommodated, but no structure was clearly superior to the DHDMBF structure.

Radiotherapeutic management of bulky cervical lymphadenopathy in squamous cell carcinoma of the head and neck: is postradiotherapy neck dissection necessary?

Although traditional recommendations for the management of bulky cervical lymphadenopathy (AJCC categories N2-3) with definitive radiotherapy call for postradiotherapy neck dissection regardless of treatment response, recent data suggests that this policy can be modified on the basis of tumor regression rate. In a series of 130 patients with stage III-IV squamous cell carcinoma of the head and neck managed with a concomitant boost-accelerated hyperfractionated radiotherapy schedule, 81 cases had cervical lymphadenopathy at the time of referral. Patients were analyzed with respect to regional control outcomes for those having complete and incomplete clinical responses during the initial 3-month follow-up interval. The general management policy has been close observation of patients demonstrating complete clinical responses to radiation rather than postradiotherapy neck dissection. Failure patterns were examined in the 58 patients classified as complete responders. Failure occurred in the primary site in 16 (28%) of these patients, while isolated neck failure occurred in only 3 (5%). Neck recurrence rates for patients with maximum lymph node size < or = 3 cm vs. > 3 cm were not statistically different at 3-year follow-up (94% vs. 86%). Among the 23 incomplete clinical responders, 18 had incomplete neck responses. Five of these patients underwent salvage neck dissection; 4 remain clinically free of recurrence. The remaining 13 patients who either refused or were not eligible for salvage surgery ultimately succumbed with persistent loco-regional disease. The policy of observation after complete response to the radiotherapy schedule employed here was associated with a very low incidence of isolated neck failures and was safe and appropriate in patients who can be followed reliably. The prognosis for patients who failed to respond in the neck was poor except for those who underwent salvage surgery.