Pyopericardium secondary to achalasia-associated squamous cell carcinoma of the oesophagus

Patients with achalasia of the oesophagus are known to be at increased risk of oesophageal squamous cell carcinoma. To our knowledge, this is the first report of an achalasia-associated oesophageal squamous cell carcinoma presenting with acute sepsis secondary to pyopericardium.

Developing and assessing the utility of a You-Tube based clinical genetics video channel for families affected by inherited tumours

We have designed and implemented the first worldwide You Tube channel with 22 videos covering common questions asked in familial cancer susceptibility clinics. We discuss the use of the videos including demographics of registered You Tube users, and what lessons have been learnt about how the general public uses medical information online. The most popular video on inheritance patterns has been watched on average 84 times per month. The mostly highly viewed videos include inheritance patterns, breast cancer screening and hereditary non-polyposis colorectal cancer. Registered viewers were more commonly male and the average age of the registered user was 45-54 years; similar to that seen in Genetics Clinics suggesting that age may not be a major barrier to access to this type of information for patients. The videos have been viewed in more than 140 countries confirming that there is clearly an audience for this type of information. Patient feedback questionnaires indicate that these videos provide a useful aide memoir for the clinic appointment, and most people would recommend them to others. In summary, You Tube videos are easy and cost effective to make. They have the ability to disseminate genetics education to a worldwide audience and may be a useful adjunct to clinical appointments.

Podoplanin mediates ECM degradation by squamous carcinoma cells through control of invadopodia stability

Invadopodia are actin-rich cell membrane projections used by invasive cells to penetrate the basement membrane. Control of invadopodia stability is critical for efficient degradation of the extracellular matrix (ECM); however, the underlying molecular mechanisms remain poorly understood. Here, we uncover a new role for podoplanin, a transmembrane glycoprotein closely associated with malignant progression of squamous cell carcinomas (SCCs), in the regulation of invadopodia-mediated matrix degradation. Podoplanin downregulation in SCC cells impairs invadopodia stability, thereby reducing the efficiency of ECM degradation. We report podoplanin as a novel component of invadopodia-associated adhesion rings, where it clusters prior to matrix degradation. Early podoplanin recruitment to invadopodia is dependent on lipid rafts, whereas ezrin/moesin proteins mediate podoplanin ring assembly. Finally, we demonstrate that podoplanin regulates invadopodia maturation by acting upstream of the ROCK-LIMK-Cofilin pathway through the control of RhoC GTPase activity. Thus, podoplanin has a key role in the regulation of invadopodia function in SCC cells, controlling the initial steps of cancer cell invasion.

PAK4 kinase activity and somatic mutation promote carcinoma cell motility and influence inhibitor sensitivity

Hepatocyte growth factor (HGF) and its receptor (c-Met) are associated with cancer cell motility and invasiveness. p21-activated kinase 4 (PAK4), a potential therapeutic target, is recruited to and activated by c-Met. In response, PAK4 phosphorylates LIM kinase 1 (LIMK1) in an HGF-dependent manner in metastatic prostate carcinoma cells. PAK4 overexpression is known to induce increased cell migration speed but the requirement for kinase activity has not been established. We have used a panel of PAK4 truncations and mutations in a combination of over-expression and RNAi rescue experiments to determine the requirement for PAK4 kinase activity during carcinoma cell motility downstream of HGF. We find that neither the kinase domain alone nor a PAK4 mutant unable to bind Cdc42 is able to fully rescue cell motility in a PAK4-deficient background. Nevertheless, we find that PAK4 kinase activity and associated LIMK1 activity are essential for carcinoma cell motility, highlighting PAK4 as a potential anti-metastatic therapeutic target. We also show here that overexpression of PAK4 harboring a somatic mutation, E329K, increased the HGF-driven motility of metastatic prostate carcinoma cells. E329 lies within the G-loop region of the kinase. Our data suggest E329K mutation leads to a modest increase in kinase activity conferring resistance to competitive ATP inhibitors in addition to promoting cell migration. The existence of such a mutation may have implications for the development of PAK4-specific competitive ATP inhibitors should PAK4 be further explored for clinical inhibition.

Increased use of laparoscopy in acute right iliac fossa pain - is it good for patients?

AIM

The use of laparoscopy, with or without appendicectomy, is becoming more common in the management of acute right iliac fossa (RIF) pain, but little is known of the 'unintended' consequences of this change. This study aimed to evaluate the impact of increased use of laparoscopy on the number and type of patients treated surgically and on the rate of negative appendicectomy.

METHOD

A prospective audit was carried out of admissions to a teaching hospital over two, 3-month periods during 2007 and 2008. The management, investigations and outcome of patients presenting with RIF pain were studied.

RESULTS

Admissions were stable over the two time-periods. There was a significant increase in the number of laparoscopic operations performed, from 22.5% (14/62) in 2007 to 85.7% (72/84) in 2008 (P < 0.0001), and the percentage of patients undergoing surgery rose from 55.4% (n = 62) in 2007 to 71.2% (n = 84) in 2008 (P < 0.01). In 2008, female patients were more likely to have surgery, an increase from 37.1% to 66.2% (P < 0.001), and were more likely to have a laparoscopic procedure, an increase from 50% to 98% (P < 0.0001). The rate of histologically confirmed appendicitis did not increase significantly (50/122 vs 57/118; P = 0.25), but the number of patients with a normal appendix either left in situ because it was macroscopically normal or found to be histologically normal following excision, increased significantly, from 9.01% in 2007 to 21.2% in 2008 (P < 0.01). The diagnostic value of pelvic ultrasound decreased from 75.6% of examinations in 2007 to 54.5% in 2008 (P = 0.039).

CONCLUSION

An increase in laparoscopic procedures has resulted in more operations in women, an associated higher negative appendicectomy rate and decreased usefulness of pelvic ultrasound. Increased use of laparoscopy needs to be balanced against the diagnostic benefits of 'negative' laparoscopy.

Microbial iron reduction by enrichment cultures isolated from estuarine sediments

Microbial Fe reduction in acetate- and succinate-containing enrichment cultures initiated with an estuarine sediment inoculum was studied. Fe reduction was unaffected when SO(4) reduction was inhibited by MoO(4), indicating that both processes could occur independently. Bacterially produced sulfide precipitated as FeS but was not completely responsible for Fe reduction. The separation of oxidized Fe particles from bacteria by dialysis tubing demonstrated that direct bacterial contact was necessary for Fe reduction. Fe reduction in cultures amended with NO(3) was delayed until NO(3) and NO(2) were removed. However, bacterial attachment to oxidized Fe particles in NO(3)-amended cultures occurred early during growth in a manner similar to NO(3)-free cultures. During late stages of growth, bacteria not attached to Fe particles became pale and swollen, while attached cells remained bright blue when examined by 4',6-diamidine-2-phenylindole epifluo-rescence microscopy. The presence of added oxidized Mn had no effect on Fe reduction. The results suggested that enzymatic Fe reduction was responsible for reducing Fe in these cultures even in the presence of sulfide and that cells incapable of Fe reduction became unhealthy when Fe(III) was the only available electron acceptor.

Quantifying cell-matrix adhesion dynamics in living cells using interference reflection microscopy

Focal adhesions and podosomes are integrin-mediated cell-substratum contacts that can be visualized using interference reflection microscopy (IRM). Here, we have developed automated image-processing procedures to quantify adhesion turnover from IRM images of live cells. Using time sequences of images, we produce adhesion maps that reveal the spatial changes of adhesions and contain additional information on the time sequence of these changes. Such maps were used to characterize focal adhesion dynamics in mouse embryo fibroblasts lacking one or both alleles of the vinculin gene. Loss of vinculin expression resulted in increased assembly, disassembly and/or in increased translocation of focal adhesions, suggesting that vinculin is important for stabilizing focal adhesions. This method is also useful for studying the rapid dynamics of podosomes as observed in primary mouse dendritic cells.

Mechanism of Phosphodiesterase 5 inhibitor relief of prostatitis symptoms

BACKGROUND

Chronic prostatitis is a common urological complaint without clearly defined causation or definitive treatment.

HYPOTHESIS

Phosphodiesterase 5 (PDE5) Inhibitor mediated relaxation of prostatic duct smooth muscle increases washout of prostatic reflux products reducing prostatic inflammation and consequent prostatitis symptoms. RATIONALE OF HYPOTHESIS: The presence of both Nitric Oxide Synthase and Phosphodiesterase 5 in human prostatic tissue and the effect of nitric oxide donors and PDE5 inhibitors in vitro indicate PDE5 inhibitors relax prostatic smooth muscle. Significant retrograde urinary flux into prostatic ducts has been described and suggested as the mechanism of chronic prostatitis. We postulate PDE5 inhibitors alter prostatic reflux hence prostatitis symptoms.

CONCLUSION

PDE5 inhibitors may represent a simple, effective treatment for chronic prostatitis.

Effect of wearing personal protective clothing and self-contained breathing apparatus on heart rate, temperature and oxygen consumption during stepping exercise and live fire training exercises

Fire fighter breathing apparatus instructors (BAIs) must possess the ability to respond to both the extrinsic stress of a high temperature environment and the intrinsic stress from wearing personal protective equipment (PPE) and self-contained breathing apparatus (SCBA), repeatedly and regularly, whilst training recruits in live fire training exercises (LFTEs). There are few previous investigations on BAIs in hot environments such as LFTEs, since the main research focus has been on regular fire fighters undertaking exercises in temperate or fire conditions at a moderate to high exercise intensity. In this study, the intrinsic cardiovascular stress effects of wearing PPE + SCBA were first investigated using a step test whilst wearing gym kit (control), weighted gym kit (a rucksack weighted to the equivalent of PPE + SCBA) and full PPE + SCBA (weight plus the effects of protective clothing). The extrinsic effects of the very hot environment were investigated in BIAs in LFTEs compared to mock fire training exercises (MFTEs), where the fire was not ignited. There was an increase in heart rate due to the modest workload imposed on the BAIs through carrying out the MFTEs (25.0 (18.7)%) compared to resting. However, when exposed to fire during the LFTEs, heat storage appears to be significant as the heart rate increased by up to 39.8 (+/-20.1)% over that of the mock LFTEs at temperate conditions. Thus, being able to dissipate heat from the PPE is particularly important in reducing the cardiovascular responses for BAIs during LFTEs.

Pharmacological rescue of noise induced hearing loss using N-acetylcysteine and acetyl-L-carnitine

Despite the use of hearing protection devices (HPDs) and engineering changes designed to improve workspaces, noise-induced hearing loss continues to be one of the most common and expensive disabilities in the US military. Many service members suffer acoustic trauma due to improper use of HPDs, sound levels exceeding the protective capacity of the HPDs, or by unexpected, injurious exposures. In these cases, there is no definitive treatment for the hearing loss. This study investigated the use of the pharmacological agents N-acetylcysteine and acetyl-L-carnitine after acoustic trauma to treat cochlear injury. N-Acetylcysteine is an antioxidant and acetyl-L-carnitine a compound that maintains mitochondrial bio-energy and integrity. N-Acetylcysteine and acetyl-L-carnitine, respectively, significantly reduced permanent threshold shifts and hair cell loss compared to saline-treated animals when given 1 and 4 h post-noise exposure. It may be possible to obtain a greater therapeutic effect using these agents in combination or at higher doses or for a longer period of time to address the secondary oxidative events occurring 7-10 days after acute noise exposure.

The effects of a high carbohydrate diet on cortisol and salivary immunoglobulin A (s-IgA) during a period of increase exercise workload amongst Olympic and Ironman triathletes

The present study observed the effects of a 6-day high carbohydrate (H-CHO) diet on salivary cortisol and IgA during a period of increased exercise workload. Thirty-two competitively trained male triathletes were randomly allocated into a self-selected (SS), or an H-CHO (12 g CHO kgbm (-1) . day (-1)) dietary group. In addition to their training regimes, all subjects performed a 1-hour running exercise bout at 70 % V.O (2max) . d (-1), for six days. Saliva samples were taken pre, immediately post, and morning post-exercise bout on days 1, 4, and 6. The concentrations of s-IgA and cortisol were determined by ELISA assays. There was a significant (p < 0.001) interaction between Group x Time for cortisol, with a marked increase in concentrations occurring in the SS dietary group pre to post exercise, and pre to morning post-exercise (p < 0.01). Conversely, a significant (p = 0.009) Group x Time interaction reflected higher post exercise s-IgA concentrations (p < 0.005) than pre exercise in the H-CHO diet group. Blood glucose concentration decreased pre to post exercise in the SS diet group (p < 0.01), whilst remaining stable in the H-CHO group. It is concluded that the consumption of a high CHO diet throughout a 6-day period of overtraining had a favourable effect on markers of immune activity and thereby reduced the susceptibility of these endurance athletes to upper respiratory tract infection URTI.

Rho family GTPases are activated during HGF-stimulated prostate cancer-cell scattering

An important process in embryogenesis and cancer-cell metastasis is the conversion of epithelial cells to a migratory phenotype, a phenomenon known as epithelial-mesenchymal transition (E-MT). To achieve E-MT, cells dissociate from neighbouring cells and adopt a migratory morphology. This transition requires remodelling of their cell shape and substratum adhesions; activities that require extensive reorganisation of the actin cytoskeleton. Hepatocyte growth factor (HGF)-induced scattering of Madin Darby canine kidney (MDCK) cells is a routinely used model of E-MT, in which actin cytoskeletal rearrangement is known to be dependent on Rho family GTPases. We have developed a novel model of HGF-induced E-MT using the human prostate cancer cell line, DU145. This model overcomes the limitation of using a canine cell line and facilitates the study of E-MT in human cancer. We demonstrate for the first time the scattering response of individual DU145 cells to HGF in real time and have characterised changes in actin cytoskeletal organisation and cell adhesions as these cells respond to HGF. HGF-induced scattering of DU145 cells is dependent on the activity of Rho family GTPases, and using this model, we are able to demonstrate for the first time that endogenous Cdc42 is activated downstream of HGF. Furthermore we have also shown that the response of DU145 cells to HGF is dependent on a phosphatidylinositide 3-kinase pathway.

A reconstructive algorithm for plastic surgery following extensive chest wall resection

Chest wall reconstruction following extensive resection is greatly facilitated by the use of vascularised flaps and prosthetic material. Plastic surgeons are often asked to assist with coverage of large chest wall defects. However, in addition to soft tissue coverage, we need to address other important issues such as the status of the pleural cavity, and the requirement for skeletal support. The purpose of this report is to analyse our experience, provide a reconstructive algorithm following the ablative procedure and review the literature. Two hundred chest wall resections were performed from 1975 to 2000. Defect location was divided into anterior (n = 73) lateral (n = 36) anterior-lateral (n = 36) posterior-lateral (n = 19) posterior (n = 22) and forequarter (n = 14) Average number of ribs resected was four. One hundred and fifty-eight patients (79%) required chest wall reconstruction with either prosthetic material and/or flap closure. Mesh closure was required in 85 cases (43%), being highest for lateral defects (61%), and lowest for anterior defects (31%). Vascularised flaps were needed in 112 patients (56%), more common in anterior defects (79%), and less common for the posterior-lateral defects (26%). Inpatient complication rate was 27% (43/158) following reconstruction, with a mortality of 6% (10/158). Chest wall reconstruction is common following extensive resection. This includes management of the pleural cavity, skeletal support and soft tissue coverage. A better understanding of the respiratory mechanics and local thoracoabdominal anatomy is crucial for managing these complex defects. The need for skeletal support was more prevalent in lateral and posterior-lateral defects. Flap reconstruction was required more often to cover large anterior defects, with regional flaps predominating.

Opioid peptides and dipeptidyl peptidase in autism

It has been hypothesized that autism results from an 'opioid peptide excess'. The aims of this study were to (1) confirm the presence of opioid peptides in the urine of children with autism and (2) determine whether dipeptidyl peptidase IV (DPPIV/CD26) is defective in children with autism. Opioid peptides were not detected in either the urine of children with autism (10 children; nine males, one female; age range 2 years 6 months to 10 years 1 month) or their siblings (10 children; seven males, three females; age range 2 years 3 months to 12 years 7 months) using liquid chromatography-ultraviolet-mass spectrometric analysis (LC-UV-MS). Plasma from 11 normally developing adults (25 years 5 months to 55 years 5 months) was also tested. The amount and activity of DPPIV in the plasma were quantified by an ELISA and DPPIV enzyme assay respectively; DPPIV was not found to be defective. The percentage of mononuclear cells expressing DPPIV (as CD26) was determined by flow cytometry. Children with autism had a significantly lower percentage of cells expressing CD3 and CD26, suggesting that they had lower T-cell numbers than their siblings. In conclusion, this study failed to replicate the findings of others and questions the validity of the opioid peptide excess theory for the cause of autism.

The muscle-specific marker desmin is expressed in a proportion of human dermal fibroblasts after their exposure to galectin-1

We have previously shown that galectin-1 is a factor capable of converting mouse dermal fibroblasts to the myogenic lineage [Cell Transplant 2000;9:519]. Here, we report that human dermal fibroblasts are also capable of expressing the myogenic marker, desmin, when grown in muscle-cell-conditioned media. Furthermore, the human foetal skin cells also express this marker when grown in the presence of galectin-1. These results highlight the importance of galectin-1 in the conversion of both human and murine skin cells to a myogenic lineage. Thus galectin-1 could be an important tool for use in autologous cell therapies for the treatment of human muscular dystrophies.

Coordination of cell polarization and migration by the Rho family GTPases requires Src tyrosine kinase activity

BACKGROUND

The ability of a cell to polarize and move is governed by remodeling of the cellular adhesion/cytoskeletal network that is in turn controlled by the Rho family of small GTPases. However, it is not known what signals lie downstream of Rac1 and Cdc42 during peripheral actin and adhesion remodeling that is required for directional migration.

RESULTS

We show here that individual members of the Rho family, RhoA, Rac1, and Cdc42, direct the specific intracellular targeting of c-Src tyrosine kinase to focal adhesions, lamellipodia, or filopodia, respectively, and that the adaptor function of c-Src (the combined SH3/SH2 domains coupled to green fluorescent protein) is sufficient for targeting. Furthermore, Src's catalytic activity is absolutely required at these peripheral cell-matrix attachment sites for remodeling that converts RhoA-dependent focal adhesions into smaller focal complexes along Rac1-induced lamellipodia (or Cdc42-induced filopodia). Consequently, cells in which kinase-deficient c-Src occupies peripheral adhesion sites exhibit impaired polarization toward migratory stimuli and reduced motility. Furthermore, phosphorylation of FAK, an Src adhesion substrate, is suppressed under these conditions.

CONCLUSIONS

Our findings demonstrate that individual Rho GTPases specify Src's exact peripheral localization and that Rac1- and Cdc42-induced adhesion remodeling and directed cell migration require Src activity at peripheral adhesion sites.

Configuration of human dendritic cell cytoskeleton by Rho GTPases, the WAS protein, and differentiation

The cellular mechanisms that configure the cytoskeleton during migration of dendritic cells (DCs) are poorly understood. Immature DCs assemble specialized adhesion structures known as podosomes at their leading edge; these are associated with the localized recruitment of the Wiskott-Aldrich Syndrome protein (WASp) and the actin organizing actin-related protein 2/3 complex. In immature DCs lacking WASp, podosomes are absent, residual dysmorphic lamellipodia and filopodia are nonpolarized, and migration is severely compromised. Microinjection studies indicate that podosome assembly and polarization require concerted action of Cdc42, Rac, and Rho, thereby providing a link between sequential protrusive and adhesive activity. Formation of podosomes is restricted to cells with an immature phenotype, indicating a specific role for these structures during the early migratory phase. (Blood. 2001;98:1142-1149)

Thoracic reconstruction with the omentum: indications, complications, and results

This study provides a retrospective analysis of 60 patients who underwent thoracic reconstruction with the omentum. Patients were identified by searching several databases to determine demographics, indications for surgery, operative technique, and postoperative course, including donor and recipient site morbidity. From January 1975 to May 2000, the authors harvested and transferred the omentum successfully (57 pedicled, 3 free) in 60 patients (mean age, 60 years; age range, 21-86 years) for sternal wound infections (N = 34), chest wall resections (N = 17), pectus deformities (N = 2), intrathoracic defects (N = 4), and breast reconstruction (N = 3). The omentum was used as a primary flap in 39 patients and as a salvage flap in 21 patients. Average operative time was 3.9 hours and average hospital stay was 34.3 days. Partial flap loss occurred in 7 patients, with no total flap failures. Morbidity included six abdominal wound infections and seven epigastric hernias. Mortality was 11.7%. The omentum can be harvested safely and used reliably to reconstruct varying thoracic wounds and defects. Specific indications from this series include osteoradionecrosis, chest wall tumors, massive sternal wounds, and refractory mediastinitis. Hultman CS, Culbertson JH, Jones GE, et al. Thoracic reconstruction with the omentum: indications, complications, and results.

The Wiskott-Aldrich syndrome: disordered actin dynamics in haematopoietic cells

The Wiskott-Aldrich syndrome protein (WASp) is a member of a unique family whose members share similar domain structures and are responsible for the transduction of signals from the cell membrane to the actin cytoskeleton. For WASp, the interactions with Rho family GTPases and the cytoskeletal organising complex Arp2/3 are critical to these functions, which when disturbed translate into abnormalities of haematopoietic cell signaling, polarisation, migration and phagocytosis. This review discusses the evidence for regulation of highly dynamic cytoskeletal structures by WASp and the consequences of disturbed function on some of these processes.

Cellular signaling in macrophage migration and chemotaxis

Whereas most cells in adult tissues are fixed in place by cell junctions, leukocytes are motile and able to migrate actively through the walls of blood vessels into surrounding tissues. The actin cytoskeleton of these cells plays a central role in locomotion, phagocytosis, and the regulation of cell shape that are crucial elements of neutrophil and monocyte/macrophage function. This review will concentrate on how macrophages in particular control the actin cytoskeleton to generate cell movement and the shape changes required for chemotaxis. It has recently become evident that a complex of seven proteins known as the Arp2/3 complex regulates the assembly of new actin filament networks at the leading front of moving cells. Proteins of the Wiskott-Aldrich Syndrome Protein (WASP) family bind directly to the Arp2/3 complex and stimulate its ability to promote the nucleation of new actin filaments. Upstream of the WASP family proteins, receptor tyrosine kinases, G-protein-coupled receptors, phosphoinositide-3-OH kinase (PI 3-kinase), and the Rho family of GTPases receive and transduce the signals that lead to actin nucleation through WASP-Arp2/3 action. Although many gaps remain in our understanding, we are now in a position to consider completing signaling pathways that are initiated from outside the cell to the actin rearrangements that drive cell motility and chemotaxis.

1-[2-[(Heteroaryloxy)heteroaryl]carbamoyl]indolines: novel and selective 5-HT2C receptor inverse agonists with potential as antidepressant/anxiolytic agents

Bisaryl ethers have been identified with excellent 5-HT2C affinity and selectivity over both 5-HT2A and 5-HT2B receptors. Compounds such as 11, 27 and 38 have potent oral activity in a centrally mediated pharmacodynamic model of 5-HT2C function and their potential as novel non-sedating anxiolytic and antidepressants is under investigation.

1-[2-[(Heteroarylmethoxy)aryl]carbamoyl]indolines are selective and orally active 5-HT2C receptor inverse agonists

Bisarylmethoxyethers have been identified with nanomolar 5-HT2C affinity and selectivity over both 5-HT2A and 5-HT2B receptors. Compounds such as 1, 2, 8, 12, 14 and 18 have potent oral activity in a centrally mediated pharmacodynamic model of 5-HT2C function and their therapeutic potential is currently under further investigation.

A factor implicated in the myogenic conversion of nonmuscle cells derived from the mouse dermis

Using the mdx mouse model for human Duchenne muscular dystrophy we have shown that a cell population residing in the dermis of C57B1/10ScSn mouse skin is capable of converting to a myogenic lineage when implanted into the mdx muscle environment. It was important to determine the characteristics of the converting cell. A previous in vitro study indicated that 10% of cells underwent conversion but only when the cells were grown in medium previously harvested from a myogenic culture. In the present study we cloned cells derived from the dermis to identify the converting cells. Clones grown in normal growth medium showed no conversion, but when grown in medium conditioned by muscle cells around 40% conversion was achieved in several individual clones. We investigated whether the protein beta-galactoside binding protein (betaGBP), which is secreted by myoblasts and acts as a cell growth regulator of fibroblasts. could be a candidate factor responsible for conversion. Medium harvested from COS-1 cells infected with a construct containing betaGBP has been used for this investigation. Growth of dermal fibroblasts in medium enriched with this factor showed a high rate of conversion to cells expressing muscle-specific factors.

Biarylcarbamoylindolines are novel and selective 5-HT(2C) receptor inverse agonists: identification of 5-methyl-1-[[2-[(2-methyl-3-pyridyl)oxy]- 5-pyridyl]carbamoyl]-6-trifluoromethylindoline (SB-243213) as a potential antidepressant/anxiolytic agent

The evolution, synthesis, and biological activity of a novel series of 5-HT(2C) receptor inverse agonists are reported. Biarylcarbamoylindolines have been identified with excellent 5-HT(2C) affinity and selectivity over 5-HT(2A) receptors. In addition, (pyridyloxypyridyl)carbamoylindolines have been discovered with additional selectivity over the closely related 5-HT(2B) receptor. Compounds from this series are inverse agonists at the human cloned 5-HT(2C) receptor, completely abolishing basal activity in a functional assay. The new series have reduced P450 inhibitory liability compared to a previously described series of 1-(3-pyridylcarbamoyl)indolines (Bromidge et al. J. Med. Chem. 1998, 41, 1598) from which they evolved. Compounds from this series showed excellent oral activity in a rat mCPP hypolocomotion model and in animal models of anxiety. On the basis of their favorable biological profile, 32 (SB-228357) and 40 (SB-243213) have been selected for further evaluation to determine their therapeutic potential for the treatment of CNS disorders such as depression and anxiety.

Frequency-dependent effects of glutamate antagonists on the vestibulo-ocular reflex of the cat

In the central nervous system, sensory and motor signals at different frequencies are transmitted most effectively by neural elements that have different dynamic characteristics. Dynamic differences may be due, in part, to the dynamics of neurotransmitter receptors. For example, N-methyl-D-aspartate (NMDA) receptors are thought to be a component of the "neural integrator" of the vestibulo-ocular reflex (VOR), which generates a signal proportional to eye position. We measured the effects of blockade of NMDA and AMPA/kainate receptors on the gain and phase of the VOR at frequencies between 0.1 and 8 Hz in alert cats. The competitive NMDA antagonist, APV, and the non-competitive antagonists, MK-801 and ketamine, all caused a pronounced reduction in VOR gain. Gain was more strongly attenuated at low frequencies (0.1-1 Hz) than at higher frequencies (2-8 Hz). The phase lead of the eye with respect to the head was increased up to 30 degrees. In contrast, the reduction in gain associated with drowsiness or surgical anesthesia was not frequency-dependent. Blockade of AMPA/kainate receptors by the competitive antagonists, CNQX and NBQX, reduced the gain of the VOR at all frequencies tested. We evaluated our results using a control systems model. Our data are consistent with participation of NMDA receptors in neural integration, but suggest that NMDA receptors also participate in transmission by other components of the VOR pathway, and that neural integration also employs other receptors. One possibility is that between 0.1 and 10 Hz, higher-frequency signals are transmitted primarily by AMPA/kainate receptors, and lower frequencies by NMDA receptors. This arrangement would provide a biological substrate for selective motor learning within a small frequency range.

Model studies on a synthetically facile series of N-substituted phenyl-N'-pyridin-3-yl ureas leading to 1-(3-pyridylcarbamoyl) indolines that are potent and selective 5-HT(2C/2B) receptor antagonists

A model series of 5-HT2C antagonists have been prepared by rapid parallel synthesis. These N-substituted phenyl-N'-pyridin-3-yl ureas were found to have a range of 5-HT2C receptor affinities and selectivities over the closely related 5-HT2A receptor. Extrapolation of simple SAR, derived from this set of compounds, to the more active but synthetically more complex 1-(3-pyridylcarbamoyl)indoline series allowed us to target optimal substitution patterns and identify potent and selective 5-HT(2C/2B) antagonists.

Effects of the presentation of false heart-rate feedback on the performance of two common heartbeat-detection tasks

Research has indicated that performance on heartbeat counting tasks may be influenced by beliefs about heart rate. Sixty male subjects were administered the Schandry heartbeat counting task after viewing fast, slow, or no heart rate feedback. Subjects were also administered the Whitehead signal-detection type task. Results indicated that subjects who received fast or no heartbeat feedback performed better on the Schandry task than subjects who received slow feedback. Feedback presentation did not affect performance on the Whitehead task. These results suggest that the Schandry task is influenced by external variables (expectations, beliefs) beyond pure awareness of "discrete" visceral sensations and, thus, may not be as powerful a method for determining awareness of individual heartbeats as some other paradigms.

Rho family proteins and cell migration

The GTP-binding proteins Rho, Rac and Cdc42 are known to regulate actin organization: Rho induces the assembly of contractile actin-based filaments such as stress fibres, Rac regulates the formation of lamellipodia and membrane ruffles, while Cdc42 is required for filopodium extension. All three proteins can also regulate the assembly of integrin-containing focal adhesion complexes. Cell migration involves co-ordinated and dynamic changes in the actin cytoskeleton and cell adhesion, and we have therefore investigated the roles of Rho family proteins in migration, using two model cell systems. First, in the macrophage cell line Bac1, Rho and Rac were found to be required for colony-stimulating factor-1 (CSF-1)-induced cell migration. In contrast, inhibition of Cdc42 does not prevent macrophages migrating in response to CSF-1, but does prevent recognition of a CSF-1 concentration gradient, so that cells now migrate randomly rather than up the gradient. This implies that Cdc42, and probably filopodia, are required for gradient sensing and cell polarization. Secondly, in the Madin-Darby canine kidney (MDCK) epithelial cell line, Rho and Rac are also essential for migration induced by hepatocyte growth factor/scatter factor. Rac is required for lamellipodium formation and is apparently activated via Ras. Interestingly, however, Rac does not induce lamellipodium formation in unstimulated MDCK cells, indicating that Rac signals differently in epithelial cells compared with fibroblasts or macrophages. Our results point to central roles for Rho, Rac and Cdc42 in co-ordinating cell migration.

The dynamics of the vestibulo-ocular reflex after peripheral vestibular damage. I. Frequency-dependent asymmetry

Accurate performance by the vestibulo-ocular reflex (VOR) is necessary to stabilize visual fixation during head movements. VOR performance is severely affected by peripheral vestibular damage; after one horizontal semicircular canal is plugged, the horizontal VOR is asymmetric and its amplitude is reduced. The VOR recovers partially. We investigated the limits of recovery by measuring the VOR's response to ipsilesional and contralesional rotation after unilateral peripheral damage in cats. We found that the VOR's response to rotation at high frequencies remained asymmetric after recovery was complete. When the stimulus was a pulse of head velocity comprising a dynamic overshoot followed by a plateau, gain was partially restored and symmetry completely restored within 30 days after the plug, but only for the plateau response. The overshoot in eye velocity remained asymmetric. The asymmetry was independent of stimulus velocity throughout the known linear velocity range of primary vestibular afferents. Sinusoidal rotation at 0.05-8 Hz revealed that, within this range, the persistent asymmetry was significant only at frequencies above 2 Hz. Asymmetry was independent of the peak head acceleration over the range of 50-500 degrees/s2. When both horizontal canals were plugged, a small residual VOR was observed, suggesting residual signal transduction by plugged semicircular canals. However, transduction by plugged canals could not explain the enhancement of the VOR gain, at high frequencies, for rotation away from the plugged side compared with rotation toward the plug. Also, the high-frequency asymmetry was present after recovery from a unilateral labyrinthectomy. These results suggest that high-frequency asymmetry after unilateral damage is not due to residual function in the plugged canal. The findings are discussed in the context of a bilateral model of the VOR that includes central filtering.

Multiple signal transduction pathways regulate TNF-induced actin reorganization in macrophages: inhibition of Cdc42-mediated filopodium formation by TNF

TNF is known to regulate macrophage (Mphi) migration, but the signaling pathways mediating this response have not been established. Here we report that stimulation of the 55-kDa TNF receptor (TNFR-1) induced an overall decrease in filamentous actin (F-actin), inhibited CSF-1- and Cdc42-dependent filopodium formation, and stimulated macropinocytosis. Using a panel of TNFR-1 mutants, the regions of the receptor required for each of these responses were mapped. The decrease in F-actin required both the death domain and the membrane proximal part of the receptor, whereas inhibition of filopodium formation and increased pinocytosis were only dependent upon a functional death domain. When the TNF-induced decrease in F-actin was inhibited using either receptor mutants or the compound D609, TNF-stimulated actin reorganization at the cell cortex became apparent. This activity was dependent upon the FAN-binding region of TNFR-1. We conclude that different domains of TNFR-1 mediate distinct changes in the Mphi cytoskeleton, and that the ability of TNF to inhibit Mphi chemotaxis may be due to decreased filopodium formation downstream of Cdc42.

The Rho GTPases in macrophage motility and chemotaxis

The GTP-binding proteins, Rho, Rac and Cdc42 are known to regulate actin organisation. Rho induces the assembly of contractile actin-based microfilaments such as stress fibres, Rac regulates the formation of membrane ruffles and lamellipodia, and Cdc42 activation is necessary for the formation of filopodia. In addition, all three proteins can also regulate the assembly of integrin-containing focal adhesion complexes. The orchestration of these distinct cytoskeletal changes is thought to form the basis of the coordination of cell motility and we have investigated the roles of Rho family proteins in migration using a model system. We have found that in the macrophage cell line Bac1, the cytokine CSF-1 rapidly induces actin reorganisation: it stimulates the formation of filopodia, lamellipodia and membrane ruffles, as well as the appearance of fine actin cables within the cell. We have shown that Cdc42, Rac and Rho regulate the CSF-1 induced formation of these distinct actin filament-based structures. Using a cell tracking procedure we found that both Rho and Rac were required for CSF-1 stimulated cell translocation. In contrast, inhibition of Cdc42 does not prevent macrophages migrating in response to CSF-1, but does prevent recognition of a CSF-1 concentration gradient, so that cells now migrate randomly rather than up the gradient of this chemotactic cytokine. This implies that Cdc42, and thus probably filopodia, are required for gradient sensing and cell polarisation in macrophages.

Intrinsic dendritic cell abnormalities in Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is an X-linked disorder characterized by immune deficiency, eczema, and microthrombocytopenia. Biochemical evidence indicates that the Wiskott-Aldrich syndrome protein (WASp) is involved in regulating the actin cytoskeleton. Here we report that WAS dendritic cells (DC) have an immunophenotype very similar to normal DC. However, as a consequence of an intrinsically abnormal cytoarchitecture, they are unable to polarize normally and have severely reduced translocational motility in vitro. These findings indicate that WASp is an essential effector for Cdc-42-mediated polarization of primary hematopoietic cells, and suggest that a significant component of the clinical phenotype of WAS could arise from peripheral DC dysmotility and aberrant immune cell trafficking in vivo. Intrinsic dysfunction of the DC population may also have an important role in the pathogenesis of other primary immunodeficiency syndromes, while induced changes in DC cytoskeletal signaling pathways may contribute to the initiation of acquired immunological and inflammatory disorders.

Retinoic acid as a chemotactic molecule in neuronal development

We describe the results of experiments on dissociated cultures of embryonic chick neural tissue which were designed to investigate further the role of all-trans-retinoic acid (tRA) on neurite outgrowth and, by inference, on the developing nervous system in vivo. We show that tRA increases both the number of neurites and the length of neurites extending from these chick neural tube cells at nM concentrations. Secondly, using the newly designed Dunn chamber in which stable gradients of compounds can be generated, we show that neurites respond to a gradient of tRA by growing up the gradient. These observations indicate a role for RA in vivo, not only in the initial outgrowth of neurites, but also in their guidance to the appropriate targets.

RhoE regulates actin cytoskeleton organization and cell migration

The actin cytoskeleton is regulated by Rho family proteins: in fibroblasts, Rho mediates the formation of actin stress fibers, whereas Rac regulates lamellipodium formation and Cdc42 controls filopodium formation. We have cloned the mouse RhoE gene, whose product is a member of the Rho family that shares (except in one amino acid) the conserved effector domain of RhoA, RhoB, and RhoC. RhoE is able to bind GTP but does not detectably bind GDP and has low intrinsic GTPase activity compared with Rac. The role of RhoE in regulating actin organization was investigated by microinjection in Bac1.2F5 macrophages and MDCK cells. In macrophages, RhoE induced actin reorganization, leading to the formation of extensions resembling filopodia and pseudopodia. In MDCK cells, RhoE induced the complete disappearance of stress fibers, together with cell spreading. However, RhoE did not detectably affect the actin bundles that run parallel to the outer membranes of cells at the periphery of colonies, which are known to be dependent on RhoA. In addition, RhoE induced an increase in the speed of migration of hepatocyte growth factor/scatter factor-stimulated MDCK cells, in contrast to the previously reported inhibition produced by activated RhoA. The subcellular localization of RhoE at the lateral membranes of MDCK cells suggests a role in cell-cell adhesion, as has been shown for RhoA. These results suggest that RhoE may act to inhibit signalling downstream of RhoA, altering some RhoA-regulated responses, such as stress fiber formation, but not affecting others, such as peripheral actin bundle formation.

A role for Cdc42 in macrophage chemotaxis

Three members of the Rho family, Cdc42, Rac, and Rho are known to regulate the organization of actin-based cytoskeletal structures. In Bac1.2F5 macrophages, we have shown that Rho regulates cell contraction, whereas Rac and Cdc42 regulate the formation of lamellipodia and filopodia, respectively. We have now tested the roles of Cdc42, Rac, and Rho in colony stimulating factor-1 (CSF-1)-induced macrophage migration and chemotaxis using the Dunn chemotaxis chamber. Microinjection of constitutively activated RhoA, Rac1, or Cdc42 inhibited cell migration, presumably because the cells were unable to polarize significantly in response to CSF-1. Both Rho and Rac were required for CSF-1-induced migration, since migration speed was reduced to background levels in cells injected with C3 transferase, an inhibitor of Rho, or with the dominant-negative Rac mutant, N17Rac1. In contrast, cells injected with the dominant-negative Cdc42 mutant, N17Cdc42, were able to migrate but did not polarize in the direction of the gradient, and chemotaxis towards CSF-1 was abolished. We conclude that Rho and Rac are required for the process of cell migration, whereas Cdc42 is required for cells to respond to a gradient of CSF-1 but is not essential for cell locomotion.

Chemotaxis of macrophages is abolished in the Wiskott-Aldrich syndrome

Wiskott-Aldrich syndrome (WAS) is a rare disease characterized by microthrombocytopenia, eczema and immune deficiency. In this study a direct-viewing chemotaxis chamber was used to analyse chemotactic responses of WAS neutrophils and macrophages in stable linear concentration gradients. In five patients with classic WAS, chemotaxis of macrophages but not of neutrophils was found to be abolished, whereas the speed of random motility of both cell types was found to be indistinguishable from control cells. This supports the existence of an essential functional link, previously suggested by biochemical studies, between Cdc42, WAS protein (WASp) and the actin cytoskeleton in primary human macrophages. Moreover, these data suggest that Cdc42-WASp-mediated filopodial extension is a requirement for chemotaxis but not for chemokinesis in these cells. Abnormal directional cell motility of macrophages and related antigen-presenting cells may play a significant part in the immune deficiency and eczema of WAS.

Novel and selective 5-HT2C/2B receptor antagonists as potential anxiolytic agents: synthesis, quantitative structure-activity relationships, and molecular modeling of substituted 1-(3-pyridylcarbamoyl)indolines

The synthesis, biological activity, and molecular modeling of a novel series of substituted 1-(3-pyridylcarbamoyl)indolines are reported. These compounds are isosteres of the previously published indole urea 1 (SB-206553) and illustrate the use of aromatic disubstitution as a replacement for fused five-membered rings in the context of 5-HT2C/2B receptor antagonists. By targeting a region of space previously identified as sterically allowed at the 5-HT2C receptor but disallowed at the 5-HT2A receptor, we have identified a number of compounds which are the most potent and selective 5-HT2C/2B receptor antagonists yet reported. 46 (SB-221284) was selected on the basis of its overall biological profile for further evaluation as a novel, potential nonsedating anxiolytic agent. A CoMFA analysis of these compounds produced a model with good predictive value and in addition good qualitative agreement with both our 5-HT2C receptor model and our proposed binding mode for this class of ligands within that model.

Molecular cloning and characterization of the genes coding for the highly immunogenic cluster of 90-kilodalton envelope proteins from the Chlamydia psittaci subtype that causes abortion in sheep

Proteins present in the outer membrane of chlamydiae that are involved in mucosal epithelial cell infection must clearly be identified and characterized if we are to understand and modify the pathogenic mechanisms utilized by these organisms. We have identified and isolated a family of four genes encoding putative outer membrane proteins (POMPs), a group of proteins of approximately 90 kDa present in the outer membrane of the subtype of Chlamydia psittaci that causes ovine enzootic abortion (strain S26/3). These proteins, although minor components, are major immunogens, as shown by the immunoblotting of chlamydial outer membrane complexes with postabortion sheep sera, and are therefore potential diagnostic and/or protective antigen candidates. Immunoblotting of the expressed amino- and carboxy-terminal halves of one of the POMPs with postabortion sheep sera showed that the major humoral immune response appeared to be directed solely against the amino-terminal half. This result, in combination with the positive immunofluorescence staining of S26/3-infected cells using POMP-specific (specific to the amino-terminal half of the proteins) monoclonal antibodies, suggests the probable surface localization of the POMPs and, more specifically, the surface exposure of the amino-terminal half of these proteins. The four pomp genes are highly homologous, sharing 82 to 100% similarity with each other (two of the genes are identical). Genes with strong and weak homologies were also detected in C. psittaci avian and feline pneumonitis strains, respectively. No pomp homologs were found in strains of C. trachomatis and C. pneumoniae, but this does not preclude their existence. The absence of homology with various subtypes of C. pecorum, which complicate the diagnosis of the ovine abortion subtype, indicates the possible suitability of the these 90-kDa proteins as serodiagnostic antigens.

Serological diagnosis of chlamydial abortion in sheep and goats: comparison of the complement fixation test and an enzyme-linked immunosorbent assay employing solubilised proteins as antigen

A new ELISA for antibodies against chlamydial abortion of ewes which uses detergent solubilised proteins (dsp) of Chlamydia psittaci as antigen (Anderson, I.E., Herring, A.J., Jones, G.E., Low, J.C., Greig, A., 1995. Development and evaluation of an indirect ELISA to detect antibodies to abortion strains of Chlamydia psittaci in sheep sera. Vet. Microbiol., 43, pp. 1-12] was compared with the complement fixation test (CFT) in screening 1000 ovine and caprine sera obtained from selected flocks/herds ('flocks') and submitted to a veterinary diagnostic laboratory. Fifteen of the 17 'flocks' had a history of abortion while the remaining two did not and were classified as 'negative flocks'. Infection with Chlamydia was confirmed during the study period in five 'flocks' using direct immunofluorescence and the modified Ziehl Neelsen stain on pathological material. The dspELISA and CFT identified 37 and 45 positive sera on 158 samples tested from these 'flocks'. Chlamydia antibodies were not detected in one of the two negative flocks, in two other flocks where the cause of abortion was undetermined and in three flocks in which the causes of abortion were diagnosed as Listeriosis and/or Salmonellosis. One of the 'negative flocks' yielded two positive reactors by CFT and five by dspELISA, suggesting infection with a cross-reactive subtype of C. pecorum. Of the five 'flocks' in which a definitive diagnosis from pathological material was not possible, four were positive by both serological tests, suggesting that the abortions were due to Chlamydia. The fifth flock, though negative by dspELISA and marginally positive in two samples by CFT, had experienced confirmed chlamydial abortions in previous lambing seasons, but culling and tetracycline treatment have prevented further abortions in the study period. Overall, the proportions of samples positive by CFT and dspELISA were similar (9.1% and 8.8%). These studies confirmed the value of the dspELISA as a screening test for chlamydial abortion. Furthermore, the dspELISA compared to the CFT is easier to perform, does not require reagent titration at each testing and uses automated assessment of results.

Comparison of five tests for the detection of antibodies against chlamydial (enzootic) abortion of ewes

Five tests for antibodies against chlamydial (enzootic) abortion of ewes were compared using 255 sera from experimentally (group 1) or naturally (group 2) infected animals, flocks free of the disease (group 3) and individual animals testing positively by the complement fixation test but from flocks with no evidence of chlamydial abortion (group 4). Sera from five specific pathogen-free lambs vaccinated with two different subtypes of Chlamydia pecorum were also included (group 5). All tests used some form of processed culture of C psitiaci as antigen. Specificities, established with group 3 and 4 sera, ranged between 96 per cent (ELISA using lipopolysaccharide antigen) and 59 per cent (Immunocomb). Reactions with group 5 sera suggested that the cause of false positive results in the field might be cross-reactive antibodies against the arthritogenic subtype of C pecorum. Sensitivities, established with groups 1 and 2 sera, ranged between 81 per cent (Immunocomb) and 51 per cent (ELISA using solubilised protein antigen). The minimum sample sizes required to be 95 per cent certain of detecting at least five seropositives in two infected flocks (combined data) were 15 to 48, dependent on the test applied. The Western blot test, applied to a proportion of samples, yielded no false positives with group 3 sera but 31.7 per cent with group 4 sera. Thus, none of the tests in this comparison emerged as sufficiently satisfactory in all respects, suggesting that further improvements in chlamydial serology must come through the use of non-native antigens or in the form of a competitive ELISA.

Rho, Rac and Cdc42 regulate actin organization and cell adhesion in macrophages

Rho family proteins are known to regulate actin organization in fibroblasts, but their functions in cells of haematopoietic origin have not been studied in detail. Bac1.2F5 cells are a colony-stimulating factor-1 (CSF-1)-dependent murine macrophage cell line; CSF-1 stimulates their proliferation and motility, and acts as a chemoattractant. CSF-1 rapidly induced actin reorganization in Bac1 cells: it stimulated the formation of filopodia, lamellipodia and membrane ruffles at the plasma membrane, as well as the appearance of fine actin cables within the cell interior. Microinjection of constitutively activated (V12)Rac1 stimulated lamellipodium formation and membrane ruffling. The dominant inhibitory Rac mutant, N17Rac1, inhibited CSF-1-induced lamellipodium formation, and also induced cell rounding. V12Cdc42 induced the formation of long filopodia, while the dominant inhibitory mutant N17Cdc42 prevented CSF-1-induced formation of filopodia but not lamellipodia. V14RhoA stimulated actin cable assembly and cell contraction, while the Rho inhibitor, C3 transferase, induced the loss of actin cables. Bac1 cells had cell-to-substratum adhesion sites containing beta1 integrin, pp125FAK, paxillin, vinculin, and tyrosine phosphorylated proteins. These ‘focal complexes’ were present in growing and CSF-1-starved cells, but were disassembled in cells injected with N17Cdc42 or N17Rac1. Interestingly, beta1 integrin did not disperse until long after focal phosphotyrosine and vinculin staining had disappeared. We conclude that in Bac1 macrophages Cdc42, Rac and Rho regulate the formation of distinct actin filament-based structures, and that Cdc42 and Rac are also required for the assembly of adhesion sites to the extracellular matrix.

Diagnosis of ovine enzootic abortion, using a competitive ELISA based on monoclonal antibodies against variable segments 1 and 2 of the major outer membrane protein of Chlamydia psittaci serotype 1

OBJECTIVE

To develop and evaluate a competitive ELISA (cELISA) specific for detection of antibodies to abortion strains of Chlamydia psittaci and C pecorum that is based on monoclonal antibodies against the 2 segments. PROCEDURA: Monoclonal antibodies were screened for binding to ELISA plates coated with elementary bodies, and were selected on the basis of positive competition with experimentally produced sera against C psittaci and lack of competition with anti-C pecorum sera. The cELISA was evaluated with field sera, and the results were compared with those obtained by complement-fixation testing and by an ELISA containing solubilized outer membrane complexes (A-ELISA).

RESULTS

The cELISA detected 9 of 10 C psittaci-infected flocks (57/125 sera, 45.6%), and in 6 of 10 flocks (27.3% of the sera), it specified correctly the infecting chlamydial species. Regarding test sensitivity, the complement-fixation test detected 6 of 10 test-positive (19.2% of the sera) flocks, whereas 7 of 10 test-positive (48.8% of the sera) flocks were detected by use of the A-ELISA. The specificity of the test was satisfactory (100%), compared with the A-ELISA (72.2%).

CONCLUSIONS

The new cELISA is a sensitive and specific assay for antibodies against C psittaci abortion strains. It is rapid and easy to perform and does not require serum dilutions. The new cELISA is, therefore, suitable as a routine test for chlamydial diagnosis and seroepidemiologic studies.

Normative data for the personal report of confidence as a speaker

Normative data for the Personal Report of Confidence as a Speaker (PRCS; Paul, 1966), a measure of public-speaking anxiety, were collected by administering the PRCS to 1109 college students. PRCS scores were examined in relation to gender, race, age, and grade-point average. No significant between-group differences were found. The findings indicate that levels of public-speaking anxiety are generally constant across gender, race, and age. Normative data for all scores across Caucasian and African-American subjects are presented.