Linking Language to Action: Enhancing Preschoolers' Communicative Abilities Within Language Stimulation

PURPOSE

Children's vocabulary and syntactic skills vary upon school entry in depth and breadth, persistently influencing academic performance, including reading. Enhancing early communicative abilities through multisensory, playful, and conversational experiences is essential and will benefit children's school readiness. This study investigated whether a language-to-action link created during language stimulation, which combines multisensory input, play, and conversation using clay, improves preschoolers' communicative abilities in terms of vocabulary, syntactic, and pragmatic language abilities more than traditional toy-based language stimulation.

METHOD

Language skills were examined in a pre- to posttest design in which 43 typically developing participants, ages 3-5 years, were randomly assigned to clay-based (n = 24) or traditional play-based (n = 19) language stimulation for 8 weeks.

RESULTS

Receptive and expressive vocabulary knowledge for items introduced in the language stimulation program, mean length of utterance (MLU), and conversational initiations improved for participants in the clay condition, whereas significant language skill growth was not observed for participants in the traditional play-based stimulation condition with toys.

CONCLUSIONS

A language-to-action link is created when children engage with open-ended materials, such as clay, as they craft target objects hands on and step by step, affording additional opportunities for language input and output. Results preliminarily suggest that using open-ended materials may enhance children's communicative abilities in receptive and expressive vocabulary, syntax/MLU, and pragmatics (i.e., conversational initiations) more than prefabricated toy objects during language stimulation.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24093780.

Visual word recognition in bilinguals: Eye-tracking evidence that L2 proficiency impacts access of L1 phonotactics

A bilingual's language system is highly interactive. When hearing a second language (L2), bilinguals access native-language (L1) words that share sounds across languages. In the present study, we examine whether input modality and L2 proficiency moderate the extent to which bilinguals activate L1 phonotactic constraints (i.e., rules for combining speech sounds) during L2 processing. Eye-movements of English monolinguals and Spanish-English bilinguals were tracked as they searched for a target English word in a visual display. On critical trials, displays included a target that conflicted with the Spanish vowel-onset rule (e.g., sp a), as well as a competitor containing the potentially-activated 'e' onset (e.g., e gg). The rule violation was processed either in the visual modality (Experiment 1) or audio-visually (Experiment 2). In both experiments, bilinguals with lower L2 proficiency made more eye movements to competitors than fillers. Findings suggest that bilinguals who have lower L2 proficiency access L1 phonotactic constraints during L2 visual word processing with and without auditory input of the constraint-conflicting structure (e.g., spa). We conclude that the interactivity between a bilingual's two languages is not limited to words that share form across languages, but also extends to sub-lexical, rule-based structures.

Individual and Sociolinguistic Differences in Language Background Predict Stroop Performance

To examine how differences in language experience and sociolinguistic context impact cognitive control, 146 Spanish-English bilingual participants were tested on a non-linguistic Stroop arrows task. Dimensions of language experience included a continuum of L2 proficiency, exposure, age of L2 acquisition, and English receptive vocabulary, along with cognitive non-verbal reasoning. Sociolinguistic context varied with more exposure to Spanish for participants in Southern California (SoCal) than in the Midwest. The task involved perceptual stimulus-stimulus conflict within stimulus features (e.g., right-pointing arrow on the left side of a display). Reaction times to trials where arrow location and direction matched (congruent), mismatched (incongruent), or arrow location was centered (neutral) were used to calculate Stroop (incongruent-congruent), facilitation (neutral-congruent), and inhibition (incongruent-neutral) effects. When examining performance on a continuum of bilingual language experience, individual differences in linguistic background (i.e., L2 proficiency and exposure, receptive vocabulary) and cognitive abilities (i.e., non-verbal reasoning abilities) predicted more efficient performance on the Stroop task. Across sociolinguistic contexts, findings revealed better performance via smaller Stroop and facilitation effects in the Midwest than in SoCal, and no group difference on the inhibition effect. We conclude that research on the cognitive consequences of bilingualism must consider a continuum of language experiences and must be situated in broader naturalistic contexts that take into account the sociolinguistic environments of language use.

First-language influence on second language speech perception depends on task demands

While listening to non-native speech, second language users filter the auditory input through their native language. We examined how bilinguals perceived second language (L2 English) sound sequences that conflicted with native-language (L1 Spanish) constraints across three experiments with different task demands. We used the L1 Spanish phonotactic constraint (i.e., rule for combining speech sounds) that vowels must precede s+consonant clusters (e.g., Spanish: estricto, "strict"). This L1 Spanish constraint may influence Spanish-English bilinguals' processing of L2 English words such as strict because of a missing initial vowel, as in estrict. We found that the extent to which bilinguals were influenced by the L1 during L2 processing depended on task demands. When metalinguistic awareness demands were low, as in the AX word discrimination task (Experiment 1), cross-linguistic effects were not observed. When metalinguistic awareness demands were high, as in the vowel detection (Experiment 2) and lexical decision (Experiment 3) tasks, response times demonstrated that bilinguals were influenced by the L1 constraint when processing L2 words beginning with an s+consonant. We conclude that bilinguals are cross-linguistically influenced by L1 phonotactic constraints during L2 processing when metalinguistic demands are higher, suggesting that L2 input may be mapped onto L1 sub-lexical representations during perception. These results extend previous research on language co-activation and speech perception by providing a more fine-grained understanding of task demands and elucidating when and where cross-linguistic phonotactic access is present during bilingual comprehension.

Assessing Language Skills in Bilingual Children: Current Trends in Research and Practice

A continuously challenging issue in the field of speech–language pathology is accurately identifying and diagnosing a language disorder in school-aged (pre-kindergarten through 5th grade) bilingual children, as bilingual children are disproportionately under- and overidentified with a language disorder. The current review focuses on the assessment of bilingual children in pre-kindergarten through fifth grade, aimed to inform teachers, pediatricians, parents, and other relevant professionals of issues surrounding assessment of these dual-language learners. We examine the barriers to assessing bilingual children for language disorders, such as the lack of availability of bilingual tests, underinformative current best practice guidelines, lack of speech–language pathologist (SLP) training/knowledge of bilingualism, and use of interpreters. We discuss the necessary considerations when SLPs use norm-referenced tests with bilingual children, such as norming samples, accurate identification of a language disorder, reliability and validity, test administration, and potential solutions to using otherwise poorly suited norm-referenced tests. We also consider research on several alternative measures to norm-referenced assessments, including dynamic assessment, nonword repetition, language sampling, nonlinguistic cognition, and parent report. We conclude by synthesizing the information in this review to offer six principles of best practices for bilingual assessment.

Does having a voice disorder hurt credibility?

OBJECTIVE

The purpose of the study was to determine whether listeners were less likely to believe a statement that is produced in an atypical voice, as compared to a typical voice. It was hypothesized that an atypical voice, characterized by abnormal roughness, strain, and pitch, would elicit increased skepticism. This hypothesis was based on previous evidence that there are negative stereotypes against individuals who have a voice disorder, and that increased difficulty processing an utterance can lead to disbelief.

METHODS

In Experiment 1, 36 listeners rated obscure trivia statements (such as "the elephant is the only mammal that cannot jump" and "the first public library was opened in Vienna in 1745") as definitely false, probably false, probably true, or definitely true. The statements were produced by a speaker who used their typical voice and simulated an atypical voice (of severe deviance according to the CAPE-V), as well as two additional control speakers with typical voices. Experiment 2 was a replication of Experiment 1 with a new set of 36 listeners and a new set of speakers. In addition, Experiment 2 examined whether reduced credibility was due to negative stereotypes and/or processing difficulty, through questionnaire data and correlation analyses.

RESULTS

The results were largely consistent with the hypothesis that statements produced in an atypical voice would be perceived as less credible. In both experiments, the percentage of definitely false ratings was higher for the atypical voice than for the typical voice and control voices, with a large effect size in Experiment 1 and a medium effect size in Experiment 2. Further, Experiment 2 suggested that reduced credibility was due to negative stereotypes but not processing difficulty.

CONCLUSION

The current study reveals a social consequence of having a voice disorder, i.e., decreased perceived credibility, with implications for job-related success.

Literature-Based Strategies for Clinical Fellow Mentorship

In the field of communication sciences and disorders, some research and guidance exist on clinical fellowship supervision for the mentor; however, there is a dearth of literature on clinical fellowship supervision from the perspective of the clinical fellow. This article begins with why the clinical fellowship experience is necessary, and then discusses clinical fellow and mentor expectations and responsibilities, clinical fellow independence, mentor qualities, and issues related to the provision of feedback. The overall goal is to enhance clinical fellow mentors' knowledge base on the clinical fellowship experience through review of current literature on supervision and mentorship.

Magnetic actuation and feedback cooling of a cavity optomechanical torque sensor

Cavity optomechanics has demonstrated remarkable capabilities, such as measurement and control of mechanical motion at the quantum level. Yet many compelling applications of optomechanics—such as microwave-to-telecom wavelength conversion, quantum memories, materials studies, and sensing applications—require hybrid devices, where the optomechanical system is coupled to a separate, typically condensed matter, system. Here, we demonstrate such a hybrid optomechanical system, in which a mesoscopic ferromagnetic needle is integrated with an optomechanical torsional resonator. Using this system we quantitatively extract the magnetization of the needle, not known a priori, demonstrating the potential of this system for studies of nanomagnetism. Furthermore, we show that we can magnetically dampen its torsional mode from room-temperature to 11.6 K—improving its mechanical response time without sacrificing torque sensitivity. Future extensions will enable studies of high-frequency spin dynamics and broadband wavelength conversion via torque mixing.

Although optomechanics enables precision metrology, measurements beyond mechanical properties often require hybrid devices. Here, Kim et al. demonstrate that a ferromagnetic needle integrated with a torsional resonator can determine the magnetic properties and amplify or cool the resonator motion.

Cross-linguistic phonotactic competition and cognitive control in bilinguals

The current study examines the relation between cognitive control and linguistic competition resolution at the sublexical level in bilinguals. Twenty-one Spanish-English bilinguals and 23 English monolinguals completed a non-linguistic Stroop task (indexing inhibitory control) and a linguistic priming/lexical decision task (indexing Spanish phonotactic constraint competition during English comprehension). More efficient Stroop performance (i.e., a smaller Stroop effect) in bilinguals was associated with decreased competition from Spanish phonotactic constraints during English comprehension. This relation was observed when nonword targets overlapped in phonotactic constraints and phonological form with preceding cognate primes (e.g., prime: stable (Spanish: estable)/target: esteriors). Findings suggest a link between non-linguistic cognitive control and co-activation of linguistic structures at the sublexical level in bilinguals.

Mechanical Strain Delivers Anti-apoptotic and Proliferative Signals to Gingival Fibroblasts

Physical forces play a critical role in the survival and proliferation of many cell types, including fibroblasts. Gingival fibroblasts are exposed to mechanical stress during mastication, orthodontic tooth movement, and wound healing following periodontal surgery. The aim of this study was to examine the effect of mechanical strain on human gingival fibroblasts (hGF). Cells were subjected to short-term (up to 60 min) and long-term (up to 48 hrs) 20% average elongation at 0.1 Hz. We monitored survival signaling by evaluating the phosphorylation status and localization of Forkhead box (FoxO) family members, which are mediators of apoptosis. We also examined strain-induced proliferation by measuring the level of proliferating cell nuclear antigen (PCNA). We observed that cyclic strain caused the phosphorylation and retention in the cytoplasm of FoxO family members. Moreover, mechanical strain resulted in increased ERK kinase phosphorylation and PCNA expression. In conclusion, cyclic strain delivers anti-apoptotic and proliferative stimuli to hGF.

Phonotactic Constraints Are Activated across Languages in Bilinguals

During spoken language comprehension, auditory input activates a bilingual's two languages in parallel based on phonological representations that are shared across languages. However, it is unclear whether bilinguals access phonotactic constraints from the non-target language during target language processing. For example, in Spanish, words with s+ consonant onsets cannot exist, and phonotactic constraints call for epenthesis (addition of a vowel, e.g., stable/estable). Native Spanish speakers may produce English words such as estudy ("study") with epenthesis, suggesting that these bilinguals apply Spanish phonotactic constraints when speaking English. The present study is the first to examine whether bilinguals access Spanish phonotactic constraints during English comprehension. In an English cross-modal priming lexical decision task, Spanish-English bilinguals and English monolinguals heard English cognate and non-cognate primes containing s+ consonant onsets or controls without s+ onsets, followed by a lexical decision on visual targets with the /e/ phonotactic constraint or controls without /e/. Results revealed that bilinguals were faster to respond to /es/ non-word targets preceded by s+ cognate primes and /es/ and /e/ non-word targets preceded by s+ non-cognate primes, confirming that English primes containing s+ onsets activated Spanish phonotactic constraints. These findings are discussed within current accounts of parallel activation of two languages during bilingual spoken language comprehension, which may be expanded to include activation of phonotactic constraints from the irrelevant language.

Auditory word recognition across the lifespan: Links between linguistic and nonlinguistic inhibitory control in bilinguals and monolinguals

Recent research suggests that bilingual experience reconfigures linguistic and nonlinguistic cognitive processes. We examined the relationship between linguistic competition resolution and nonlinguistic cognitive control in younger and older adults who were either bilingual or monolingual. Participants heard words in English and identified the referent among four pictures while eye-movements were recorded. Target pictures (e.g., cab) appeared with a phonological competitor picture (e.g., cat) and two filler pictures. After each eye-tracking trial, priming probes assessed residual activation and inhibition of target and competitor words. When accounting for processing speed, results revealed that age-related changes in activation and inhibition are smaller in bilinguals than in monolinguals. Moreover, younger and older bilinguals, but not monolinguals, recruited similar inhibition mechanisms during word identification and during a nonlinguistic Stroop task. Results suggest that, during lexical access, bilinguals show more consistent competition resolution and recruitment of cognitive control across the lifespan than monolinguals.

Six principles of language development: implications for second language learners

The number of children growing up in dual language environments is increasing in the United States. Despite the apparent benefits of speaking two languages, children learning English as a second language (ESL) often face struggles, as they may experience poverty and impoverished language input at home. Early exposure to a rich language environment is crucial for ESL children's academic success. This article explores how six evidenced-based principles of language learning can be used to provide support for ESL children.

Optical racetrack resonator transduction of nanomechanical cantilevers

Optomechanical transduction has demonstrated its supremacy in probing nanomechanical displacements. In order to apply nano-optomechanical systems (NOMS) as force and mass sensors, knowledge about the transduction responsivity (i.e. the change in measured optical transmission with nanomechanical displacement) and its tradeoffs with system design is paramount. We compare the measured responsivities of NOMS devices with varying length, optomechanical coupling strength gom, and optical cavity properties. Cantilever beams 1.5 to 5 μm long are fabricated 70 to 160 nm from a racetrack resonator optical cavity and their thermomechanical (TM) noise signals are measured. We derive a generic expression for the transduction responsivity of the NOMS in terms of optical and mechanical system parameters such as finesse, optomechanical coupling constant, and interaction length. The form of the expression holds direct insight as to how these parameters affect the responsivity. With this expression, we obtain the optomechanical coupling constants using only measurements of the TM noise power spectra and optical cavity transmission slopes. All optical pump/probe operation is also demonstrated in our side-coupled cantilever-racetrack NOMS. Finally, to assess potential operation in a gas sensing environment, the TM noise signal of a device is measured at atmospheric pressure.

Zinc transporters in prostate cancer

Prostate cancer is a major health concern as it has the second highest incidence rate among cancers in men. Despite progress in tumor diagnostics and therapeutic approaches, prognosis for men with advanced disease remains poor. In this review we provide insight into the changes of the intermediary metabolism in normal prostate and prostate cancer. In contrast to normal cells, prostate cancer cells are reprogrammed for optimal energy-efficiency with a functional Krebs cycle and minimal apoptosis rates. A key element in this relationship is the uniquely high zinc level of normal prostate epithelial cells. Zinc is transported by the SLC30 and SLC39 families of zinc transporters. However, in prostate cancer the intracellular zinc content is remarkably reduced and expression levels of certain zinc transporters are altered. Here, we summarize the role of different zinc transporters in the development of prostate cancer.

Quantitative magneto-mechanical detection and control of the Barkhausen effect

Quantitative characterization of intrinsic and artificial defects in ferromagnetic structures is critical to future magnetic storage based on vortices or domain walls moving through nanostructured devices. Using torsional magnetometry, we observe finite size modifications to the Barkhausen effect in the limiting case of a single vortex core interacting with individual pointlike pinning sites in a magnetic thin film. The Barkhausen effect in this limit becomes a quantitative two-dimensional nanoscale probe of local energetics in the film. Tailoring the pinning potential using single-point focused ion beam implantation demonstrates control of the effect and points the way to integrated magneto-mechanical devices incorporating quantum pinning effects.

Abatement of mixing in shear-free elongationally unstable viscoelastic microflows

The addition of minute amounts of chemically inert polyacrylamide polymer to liquids results in large instabilities under steady electro-osmotic pumping through 2 : 1 constrictions, demonstrating that laminar flow conditions can be broken in electro-osmotic flow of viscoelastic material. By excluding shear and imposing symmetry we create a platform where only elongational viscoelastic instabilities, and diffusion, affect mixing. In contrast to earlier studies with significant shear that found up to orders of magnitude increase in mixing we find that inclusion of polymers excites large viscoelastic instabilities yet mixing is reduced relative to polymer-free liquids. The absolute decrease in mixing we find is consistent with the understanding that adding polymer increases viscosity while viscoelastic flows progress towards elastic turbulence, a type of mild (Batchelor) turbulence, and indicates that electro-osmotic pumped devices are an ideal platform for studying viscoelastic instabilities without supplementary factors.

The Rafts of the Medusa: cholesterol targeting in cancer therapy

In this issue of Oncogene, Mollinedo and co-workers present promising evidence that cholesterol-sensitive signaling pathways involving lipid rafts can be therapeutically targeted in multiple myeloma. Because the pathways considered in their study are used by other types of tumor cells, one implication of this report is that cholesterol-targeting approaches may be applicable to other malignancies.

Extensional instability in electro-osmotic microflows of polymer solutions

Fluid transport in microfluidic systems typically is laminar due to the low Reynolds number characteristic of the flow. The inclusion of suspended polymers imparts elasticity to fluids, allowing instabilities to be excited when substantial polymer stretching occurs. For high molecular weight polymer chains we find that flow velocities achievable by standard electro-osmotic pumping are sufficient to excite extensional instabilities in dilute polymer solutions. We observe a dependence in measured fluctuations on polymer concentration which plateaus at a threshold corresponding to the onset of significant molecular crowding in macromolecular solutions; plateauing occurs well below the overlap concentration. Our results show that electro-osmotic flows of complex fluids are disturbed from the steady regime, suggesting potential for enhanced mixing and requiring care in modeling the flow of complex liquids such as biopolymer suspensions.

Microwave frequency sensor for detection of biological cells in microfluidic channels

We present details of an apparatus for capacitive detection of biomaterials in microfluidic channels operating at microwave frequencies where dielectric effects due to interfacial polarization are minimal. A circuit model is presented, which can be used to adapt this detection system for use in other microfluidic applications and to identify ones where it would not be suitable. The detection system is based on a microwave coupled transmission line resonator integrated into an interferometer. At 1.5 GHz the system is capable of detecting changes in capacitance of 650 zF with a 50 Hz bandwidth. This system is well suited to the detection of biomaterials in a variety of suspending fluids, including phosphate-buffered saline. Applications involving both model particles (polystyrene microspheres) and living cells-baker's yeast (Saccharomyces cerevisiae) and Chinese hamster ovary cells-are presented.

Time-domain control of ultrahigh-frequency nanomechanical systems

Nanoelectromechanical systems could have applications in fields as diverse as ultrasensitive mass detection and mechanical computation, and can also be used to explore fundamental phenomena such as quantized heat conductance and quantum-limited displacement. Most nanomechanical studies to date have been performed in the frequency domain. However, applications in computation and information storage will require transient excitation and high-speed time-domain operation of nanomechanical systems. Here we show a time-resolved optical approach to the transduction of ultrahigh-frequency nanoelectromechanical systems, and demonstrate that coherent control of nanomechanical oscillation is possible through appropriate pulse programming. A series of cantilevers with resonant frequencies ranging from less than 10 MHz to over 1 GHz are characterized using the same pulse parameters.

Microfluidic electromanipulation with capacitive detection for the mechanical analysis of cells

The mechanical behavior of cells offers insight into many aspects of their properties. We propose an approach to the mechanical analysis of cells that uses a combination of electromanipulation for stimulus and capacitance for sensing. To demonstrate this approach, polystyrene spheres and yeast cells flowing in a 25 mumx100 mum microfluidic channel were detected by a perpendicular pair of gold thin film electrodes in the channel, spaced 25 mum apart. The presence of cells was detected by capacitance changes between the gold electrodes. The capacitance sensor was a resonant coaxial radio frequency cavity (2.3 GHz) coupled to the electrodes. The presence of yeast cells (Saccharomyces cerevisiae) and polystyrene spheres resulted in capacitance changes of approximately 10 and 100 attoFarad (aF), respectively, with an achieved capacitance resolution of less than 2 aF in a 30 Hz bandwidth. The resolution is better than previously reported in the literature, and the capacitance changes are in agreement with values estimated by finite element simulations. Yeast cells were trapped using dielectrophoretic forces by applying a 3 V signal at 1 MHz between the electrodes. After trapping, the cells were displaced using amplitude and frequency modulated voltages to produce modulated dielectrophoretic forces. Repetitive displacement and relaxation of these cells was observed using both capacitance and video microscopy.

Dynamics of an Ising chain under local excitation: a scanning tunneling microscopy study of Si(100) dimer rows at 5 K

An extension of the classical Ising model to a situation including a source of spin-flip excitations localized on the scale of individual spins is considered. The scenario is realized by scanning tunneling microscopy of the Si(100) surface at low temperatures. Remarkable details, corresponding to the passage of phasons through the tunnel junction, are detected by the STM within the short span between two atoms comprising an individual Si dimer.

Nonequilibrium domain pattern formation in mesoscopic magnetic thin film elements assisted by thermally excited spin fluctuations

The dynamic behavior in the evolving pattern of thermally assisted, nonequilibrium domains in magnetic thin-film elements undergoing ultrafast 180 degrees magnetization reversal was studied. Magnetization reversal enters a fully dynamic regime when the external field conditions are changed much faster than the sample is able to respond. The dynamic pathway develops a complexity not seen in quasistatic reversal but still retains a high level of order with well-developed dynamic domain patterns formed in response to subnanosecond transitions of the external applied magnetic field.

Angiogenic switch and vascular stability in human Leydig cell tumours

The high degree of vascularisation, accompanied by the low malignancy of human Leydig cell tumours, offers an interesting model to study the neovascularisation and structural stabilisation of the vascular wall. We report here that Leydig cell tumours are characterised by an increased level of vascular endothelial growth factor (VEGF) in testicular veins, the presence of VEGF mRNA and of its receptor, KDR, and an absence of detectable VEGF receptor Flt-1, in blood vessels of tumour marginal zones and of peri-tumour areas. This is in contrast to the capillaries within normal Leydig cell clusters which demonstrate both Flt-1 and KDR. Ultrastructural destabilisation of the vascular wall, evident as a lack of basement membrane and of peri-endothelial cells was also present in nearly 85% of blood vessels of the peri-tumour areas. In contrast, approximately 89% of the blood vessels of the tumour centre region demonstrated a stabilised vascular wall including basement membrane and peri-endothelial cells. Local application of VEGF(165) to the normal testicular tissue induced significant ultrastructural destabilisation in the capillary walls which only expressed KDR. These results suggest an autocrine role of VEGF on endothelial cells of tumour blood vessels in a region-specific manner and implicate that VEGF interactions with KDR, in the absence of Flt-1, may be involved in vascular destabilisation. In addition, the finding that most (79%) of Leydig tumour blood vessels are stabilised may account for the low malignant potential of these tumours.

Male partner screening before in vitro fertilization: preselecting patients who require intracytoplasmic sperm injection with the sperm penetration assay

OBJECTIVES

To determine the diagnostic accuracy of the sperm penetration assay (SPA) and standard semen parameters for subsequent fertilization in in vitro fertilization-embryo transfer (IVF-ET).

DESIGN

Prospective study.

SETTING

Andrology Laboratory, and university research laboratory.

PATIENTS

Two hundred sixteen couples undergoing male-partner screening before IVF-ET (265 cycles).

INTERVENTION(S)

Male-partner screening (semen analyses [SA] and SPA), standard IVF-ET procedures, follow-up of fertilization in IVF-ET.

MAIN OUTCOME MEASURE(S)

Diagnostic accuracy of SA and SPA for prediction of fertilization in IVF-ET.

RESULT(S)

The SPA predicted IVF fertilization with high negative (84%) and positive (98%) predictive rates, and correct prediction in 88% of cycles. In contrast, sperm concentration, motility, morphology, and complete SA showed poor diagnostic accuracy, with correct prediction of IVF fertilization in 64%, 65%, 45%, and 68% of cycles, respectively.

CONCLUSION(S)

Very low sperm concentration and/or motility were good predictors of poor IVF fertilization, however, low to normal semen parameters were not predictive of successful IVF fertilization. The SPA is a useful screening tool that predicts IVF fertilization with high diagnostic accuracy. The SPA may be useful to discriminate between those couples with a high probability of normal fertilization in IVF and those with a low probability of normal fertilization that may benefit from assisted fertilization by intracytoplasmic sperm injection (ICSI).

Advances in magnetic microscopy

A remarkable number of methods for direct, real-space imaging in magnetic microscopy have been demonstrated over the past decade and a half, and the pace of development shows no sign of slowing. Our understanding of magnetism increases as each striking new image of surface and thin-film magnetization is obtained. The continued development of high-performance magnetic information technologies also requires detailed study of the magnetostatics and dynamics of microscopic magnetic structures. Both fundamental curiosity and practical interest now drive us toward innovations in magnetic microscopy for nanometer-length scale and femtosecond temporal resolutions, which are beyond the limits of traditional imaging techniques. This survey is intended to provide an overview of the motivations, accomplishments, and future prospects for this discipline.

Moving muscle. Jeb signaling in Drosophila

A recent study identifies a novel nonautonomous signaling pathway that regulates cell migration and differentiation in early Drosophila mesodermal tissues.

Asymmetric Prospero localization is required to generate mixed neuronal/glial lineages in the Drosophila CNS

In many organisms, single neural stem cells can generate both neurons and glia. How are these different cell types produced from a common precursor? In Drosophila, glial cells missing (gcm) is necessary and sufficient to induce glial development in the CNS. gcm mRNA has been reported to be asymmetrically localized to daughter cells during precursor cell division, allowing the daughter cell to produce glia while precursor cell generates neurons. We show that (1) gcm mRNA is uniformly distributed during precursor cell divisions; (2) the Prospero transcription factor is asymmetrically localized into the glial-producing daughter cell; (3) Prospero is required to upregulate gcm expression and induce glial development; and (4) mislocalization of Prospero to the precursor cell leads to ectopic gcm expression and the production of extra glia. We propose a novel model for the separation of glia and neuron fates in mixed lineages in which the asymmetric localization of Prospero results in upregulation of gcm expression and initiation of glial development in only precursor daughter cells.

BAG-1 is a novel cytoplasmic binding partner of the membrane form of heparin-binding EGF-like growth factor: a unique role for proHB-EGF in cell survival regulation

Several cell functions related to growth and survival regulation have been attributed specifically to the membrane form of heparin-binding EGF-like growth factor (proHB-EGF), rather than to the diffusible, processed HB-EGF isoform. These findings suggest the existence of a functional binding partner specifically for the membrane form of the growth factor. In this study we have identified the prosurvival cochaperone, BAG-1, as a protein that interacts with the cytoplasmic tail domain of proHB-EGF. Interaction between BAG-1 and the 24-amino acid proHB-EGF cytoplasmic tail was initially identified in a yeast two-hybrid screen and was confirmed in mammalian cells. The proHB-EGF tail bound BAG-1 in an hsp70-independent manner and within a 97-amino acid segment that includes the ubiquitin homology domain in BAG-1 but does not include the hsp70 binding site. Effects of BAG-1 and proHB-EGF co-expression were demonstrated in cell adhesion and cell survival assays and in quantitative assays of regulated secretion of soluble HB-EGF. Because the BAG-1 binding site is not present on the mature, diffusible form of the growth factor, these findings suggest a new mechanism by which proHB-EGF, in isolation from the diffusible form, can mediate cell signaling events. In addition, because effects of BAG-1 on regulated secretion of soluble HB-EGF were also identified, this interaction has the potential to alter the signaling capabilities of both the membrane-anchored and the diffusible forms of the growth factor.

Partial ureteral obstruction dysregulates the renal renin-angiotensin system in the fetal sheep kidney

OBJECTIVES

To investigate whether partial ureteral obstruction (PUO) in the fetus induces dysregulation of the renin-angiotensin system (RAS) and of transforming growth factor-beta 1 (TGF-beta1) and tissue inhibitors of metalloproteinase (TIMP1) expression. Previous studies have indicated that renal and urinary tract development depend on an intact renal RAS. Fetal urinary obstruction is distinct from postnatal obstruction. It has been suggested in postnatal animal studies that dysregulation of the RAS, and subsequent increased expression of TGF-beta1 and TIMP1, leads to changes in extracellular matrix composition.

METHODS

Bilateral PUO was created in 4 fetal sheep. Seven animals (four obstructed and three controls) were killed at birth and their kidneys removed. Semiquantitative reverse transcriptase-polymerase chain reaction was used to quantify the levels of renin, angiotensinogen, angiotensin receptor type 1 (AT1 receptor), angiotensin receptor type 2 (AT2 receptor), TGF-beta1, and TIMP1. These messages were normalized to glyceraldehyde-3-phosphate dehydrogenase mRNA.

RESULTS

All obstructed animals had moderate to severe hydronephrosis with enlarged kidneys (mean weight 22.0 g versus 9.4 g for the control animals; P <0.05). The increase in the levels of renin, angiotensinogen, AT1 receptor, TGF-beta1, and TIMP1 mRNA was significant in the PUO group compared with the control group (P <0.05). AT2 receptor levels did not increase, but the AT1/AT2 mRNA ratio was significantly increased over normal (P <0.005). Also, a significant linear correlation was found between the increased renal weight and increased TGF-beta1 mRNA levels (P <0.005).

CONCLUSIONS

Our findings suggest that fetal PUO can cause upregulation of the renal RAS and increased expression of TGF-beta1 and TIMP1, which may alter the balance between the generation and degradation of the extracellular matrix. The coordinate increases in renin, angiotensinogen, and AT1 receptor mRNA levels in chronic fetal PUO may represent a maladaptive response that contributes to interstitial fibrosis and prolonged vasoconstriction. RAS components and growth factors, particularly TGF-beta1, may be considered relevant targets in the prevention and treatment of congenital obstructive nephropathy.

CaT1 expression correlates with tumor grade in prostate cancer

Ca(2+) signaling is important for growth and survival of prostatic carcinoma (PCa) cells. Here we report that the gene for CaT1, a channel protein highly selective for Ca(2+), is expressed at high levels in human PCa and in the LNCaP PCa cell line. CaT1 mRNA levels were elevated in PCa specimens in comparison to benign prostatic hyperplasia (BPH) specimens and positively correlated with Gleason grade in a PCa series. CaT1 mRNA was suppressed by androgen and was induced by a specific androgen receptor antagonist in LNCaP cells, suggesting that the gene is negatively regulated by androgen. These findings are the first to implicate a Ca(2+) channel in PCa progression and suggest that CaT1 may be a novel target for therapy.

Effects of rhythm regularization and rate control in improving left ventricular function in atrial fibrillation patients undergoing atrioventricular nodal ablation

OBJECTIVES

To assess the relative contributions of rate control and rhythm regularization to left ventricular function in atrial fibrillation (AF) patients undergoing atrioventricular nodal ablation. This was performed by assessing the effect of ventricular rhythm regularization on left ventricular function during AF, and the effect of varying heart rate on left ventricular function after ablation.

PATIENTS AND METHODS

Eleven patients with continuous AF and V/VI-R pacemakers undergoing therapeutic atrioventricular nodal ablation were studied. Preablation patients underwent two 30 min observation periods in a randomized, blinded fashion during which they were either in baseline AF (pacer set to default V/VI 50/min) or being paced using a rhythm stabilizing algorithm (RSA) designed to regularize rhythm without changing baseline ventricular rate. Six weeks after ablation, patients were again observed during the two following 30 min periods: pacing at a low clinically indicated rate (69+/-9 beats/min), and pacing at the rapid, mean preablation rate. During all observation periods, left ventricular function was measured continuously using a nuclear vest that provided validated measures of heart rate, ejection fraction, and normalized end-systolic volume (ESV) and end-diastolic (EDV) volume.

RESULTS

Before ablation, RSA successfully regularized rhythm, decreasing the coefficient of variation of interbeat intervals 20+/-5% to 10+/-4% (P<0.001). The heart rate with RSA (105+/-19 beats/min) was not significantly different from the baseline AF rate (102+/-21 beats/min). Increased rhythm regularity achieved by RSA significantly improved left ventricular function, decreasing ESV from 62+/-12 units to 57+/-11 units (P=0.03), and increasing the ejection fraction from 31+/-11% to 36+/-11% (P=0.03). After ablation, at the clinically indicated low pacing rate of 69+/-9 beats/min, a much greater improvement in ejection fraction was observed, increasing to 44+/-13% (P=0.005 compared with preablation). However, rapid regular pacing at the mean preablation rate of 110+/-18 beats/min eradicated this improvement, decreasing the ejection fraction to 31+/-8% (P=0.003), and increasing ESV from 53+/-13 units to 62+/-8 units (P=0.006).

CONCLUSIONS

Rhythm regularity achieved by a regularizing pacing algorithm can significantly, albeit modestly, improve left ventricular function in AF. However, more marked improvements in left ventricular function seen after ablation are primarily due to rate reduction alone.

Prognostic value of dipyridamole SPECT imaging in low-risk patients after myocardial infarction

BACKGROUND

The prognostic value of perfusion imaging was assessed in low-risk patients after myocardial infarction (MI) and compared with clinical and angiographic variables.

METHODS AND RESULTS

Rest thallium and dipyridamole technetium 99m sestamibi single photon emission computed tomography imaging was performed in 203 (91%) low-risk patients 3 to 21 days after MI who were enrolled in a trial of low-dose warfarin sodium and aspirin. Patients were considered low risk with planned nonintervention, on the basis of an uncomplicated course after MI, negative submaximal stress electrocardiography, and the absence of significant angiographic disease requiring revascularization. During a minimum follow-up of 12 months, 69 patients (34%) had clinical events: 1 cardiac death, 7 MIs, 26 admissions for unstable angina, 18 coronary bypass grafting, and 17 angioplasty. Univariate analysis identified the extent of significant angiographic stenoses (> or =70%) and the extent of scintigraphic defect as predictive of future events. On multivariate analysis, the presence of any scintigraphic reversibility had the strongest correlation with clinical events, with better predictive value than angiographic multivessel stenoses (P =.0006 vs P =.003).

CONCLUSIONS

In the low-risk population after MI, scintigraphic reversibility remains a strong predictor of cardiac events, with greater prognostic value than angiographic data. The extent of scintigraphic reversibility was directly correlated with clinical events. Therefore scintigraphic imaging remains clinically relevant for risk stratification in the current low-risk population after MI.

Ultrafast magnetization reversal dynamics investigated by time domain imaging

Spatiotemporal magnetization reversal dynamics in a Ni(80)Fe(20) microstructure is studied using ps time scale scanning Kerr microscopy. Time domain images reveal a striking change in the reversal associated with the reduction in switching time when a transverse bias field is applied. Magnetization oscillations subsequent to reversal are observed at two resonance frequencies, which sensitively depend on the bias field strength. The oscillation at f = 2 GHz is caused by the damped precession of M, while the lower frequency approximately 0.8 GHz mode is interpreted in terms of domain wall oscillation.

Heparin-binding epidermal growth factor-like growth factor is an autocrine mediator of human prostate stromal cell growth in vitro

PURPOSE

The physiological mechanisms by which soluble mediators of cell proliferation and survival alter expansion of the prostatic stroma in benign prostatic hyperplasia are poorly understood. We recently identified heparin-binding epidermal growth factor like growth factor (HB-EGF) as a product predominantly of the smooth muscle cell compartments of the adult human prostate. We assess the potential role of this growth factor as a stromal cell regulator.

MATERIALS AND METHODS

Primary cultures of desmin and alpha-actin positive human prostate stromal cells were shown to express several cell associated HB-EGF isoforms as well as the primary cognate HB-EGF receptor, ErbB1/HER1, suggesting the existence of an autocrine or juxtacrine regulatory loop. The related receptor tyrosine kinase, ErbB2/HER2, was also expressed as assessed by reverse transcriptase (RT) polymerase chain reaction (PCR). HB-EGF messenger RNA levels in human prostate stromal cells increased modestly (70%) in response to a repetitive mechanical stimulus, a lower response than has been reported for neonatal rat bladder smooth muscle cells, in which HB-EGF was originally identified as a mechanically responsive gene.

RESULTS

HB-EGF, epidermal growth factor and basic fibroblast growth factor stimulated human prostate stromal cell growth, while a specific antagonist of HB-EGF, [Glu52]-diphtheria toxin/CRM197, inhibited human prostate stromal growth in serum-free medium by a mechanism that did not involve increased apoptosis. A function blocking antibody against CD9/DRAP27/MRP-1, a cell surface binding partner of the membrane form of HB-EGF, also stimulated human prostate stromal cell proliferation.

CONCLUSIONS

HB-EGF is an endogenously produced human prostate stromal cell growth factor and, thus, may have a role as a physiologically relevant autocrine or juxtacrine mediator of stromal expansion in benign prostatic hyperplasia.

Cyclic stretch activates p38 SAPK2-, ErbB2-, and AT1-dependent signaling in bladder smooth muscle cells

Cyclic mechanical stretch of bladder smooth muscle cells (SMC) increases rates of DNA synthesis and stimulates transcription of the gene for heparin-binding epidermal growth factor-like growth factor (HB-EGF), an ErbB1/EGF receptor ligand that has been linked to hypertrophic bladder growth. In this study we sought to clarify the signaling pathways responsible for mechanotransduction of the stretch stimulus. HB-EGF mRNA levels, DNA synthesis, and AP-1/Ets DNA binding activities were induced by repetitive stretch of primary culture rat bladder SMC. Inhibitors of the p38 SAPK2 pathway, the angiotensin receptor type 1 (AT1), and the ErbB2 tyrosine kinase reduced each of these activities, while an inhibitor of the extracellular signal-regulated kinase mitogen-activated protein kinase (Erk-MAPK) pathway had no effect. Stretch rapidly activated stress-activated protein kinase 2 (p38 SAPK2) and Jun NH(2)-terminal kinase (JNK)/SAPK pathways but not the Erk-MAPK pathway and induced ErbB2 but not ErbB1 phosphorylation. Angiotensin II (ANG II) a bladder SMC mitogen previously linked to the stretch response, did not activate ErbB2, and ErbB2 activation occurred in response to stretch in the presence of an ANG receptor inhibitor, indicating that activation of the AT1-mediated pathway and the ErbB2-dependent pathway occurs by independent mechanisms. p38 SAPK2 and JNK/SAPK signaling also appeared to be independent of the ErbB2 and AT1 pathways. These findings indicate that stretch-stimulated DNA synthesis and gene expression in normal bladder SMC occur via multiple independent receptor systems (e.g., AT1 and ErbB2) and at least one MAPK pathway (p38 SAPK2). Further, we show that the Erk-MAPK pathway, which in most systems is linked to receptor-dependent cell growth responses, is not involved in progression to DNA synthesis or in the response of the HB-EGF gene to mechanical forces.

Heparin-binding EGF-like growth factor is up-regulated in the obstructed kidney in a cell- and region-specific manner and acts to inhibit apoptosis

The expression of certain growth factors in the epidermal growth factor (EGF) family is altered in response to renal injury. Recent studies have demonstrated that heparin binding EGF-like growth factor (HB-EGF) expression may be cytoprotective in response to apoptotic signals. The purpose of this study was to investigate the potential role of HB-EGF in the upper urinary tract following unilateral ureteral obstruction. We present evidence that: i) ureteral obstruction induced cell-specific but transient activation of HB-EGF gene expression; ii) HB-EGF expression in renal epithelial cells increased under conditions where mechanical deformation, such as that caused by hydronephrotic distension, induces apoptosis, but HB-EGF expression did not increase in renal pelvis smooth muscle cells under identical conditions; and iii) enforced expression of HB-EGF served to protect renal epithelial cells from stretch-induced apoptosis. These results suggest a potential mechanism by which the kidney protects itself from apoptosis triggered by urinary tract obstruction.

A nontoxic diphtheria toxin analogue inhibits neonatal bladder smooth muscle cell proliferation

PURPOSE

The response of the neonatal bladder to infravesical obstruction, such as posterior urethral valves or detrusor-sphincter dyssynergia, may result in structural and functional changes that persist well after obstruction is treated. A pharmacological means of inhibiting smooth muscle cell proliferation would likely serve to halt or reverse this deleterious process. Heparin binding (HB) epidermal growth factor (EGF) is a known smooth muscle cell mitogen, while its membrane bound precursor serves as the diphtheria toxin receptor. We report the effects of the nontoxic diphtheria toxin analogue cross reacting material (CRM) 197 on neonatal sheep bladder smooth muscle cell proliferation.

MATERIALS AND METHODS

Neonatal sheep smooth muscle cell cultures were obtained from whole bladder explants. Immunohistochemical staining was performed for desmin and alpha-smooth muscle actin. HB-EGF messenger RNA was detected by reverse transcriptase polymerase chain reaction using primers to the human sequence, while pro-HB-EGF peptide was confirmed using a diphtheria toxin sensitivity assay with incorporation of tritiated leucine. Cells grown in 96 well plates were exposed to 1, 10 and 100 microg./ml. CRM 197 for 5 days, after which relative cell number was determined using an 3-[4,5-dimethylthiazol-2-yl] -2,5-diphenyltetrazolium bromide; thiazolyl blue based assay read at a wavelength of 550 nm. Statistical analysis was performed using Student's t test.

RESULTS

Primary cell cultures stained positive for desmin and alpha-smooth muscle actin, confirming a smooth muscle origin. Reverse transcriptase polymerase chain reaction yielded a 453 bp product with 88% homology to human HB-EGF. Total protein synthesis significantly decreased when cells were incubated with diphtheria toxin, confirming the presence of membrane bound pro-HB-EGF. CRM 197 inhibited bladder smooth muscle cell growth in a dose dependent fashion at a concentration of 10 microg./ml., resulting in a 40% decrease in proliferation (p <0.0001).

CONCLUSION

CRM 197 inhibits bladder smooth muscle cell proliferation in a dose dependent, nontoxic fashion through its interaction with HB-EGF. These data suggest that molecular strategies designed to inhibit HB-EGF mediated cell growth may prove beneficial for the prevention and/or treatment of detrusor hypertrophy secondary to anatomical or functional bladder outlet obstruction.

Amphiregulin is coordinately expressed with heparin-binding epidermal growth factor-like growth factor in the interstitial smooth muscle of the human prostate

Peptide growth factors have been proposed as mediators of smooth muscle-epithelial cell interactions in the human prostate; however, the identity of these molecules has not been established. In this study, we compared expression levels of messenger RNAs (mRNAs) encoding the epidermal growth factor (EGF) receptor-related receptor tyrosine kinases (ErbB1 through 4), the six EGF receptor ligands, EGF, transforming growth factor (TGF)-alpha, amphiregulin (ARG), HB-EGF, betacellulin, and epiregulin, and the related molecule heregulin-alpha, in a series of 10 prostate tissue specimens. Only EGF showed a disease-specific association, with increased mRNA levels in four of five PCa specimens in comparison to matched normal tissue from the same subject. In contrast, ARG and HB-EGF mRNAs showed a coordinate pattern of expression in 7/10 specimens that was distinct from all other growth factor or receptor genes examined and from mRNAs for prostate specific antigen, the androgen receptor and GAPDH, a house-keeping enzyme. Analysis of an additional series of benign prostatic hyperplasia and prostate cancer specimens from 60 individuals confirmed that ARG and HB-EGF mRNA levels varied in a highly coordinate manner (r = 0.93; P < 0.0001) but showed no association with disease. ARG was immunolocalized largely to interstitial smooth muscle cells (SMC), previously identified as the site of synthesis of HB-EGF in the prostate, while the cognate ARG and HB-EGF receptor, ErbB1, was localized exclusively to ductal epithelial cells and carcinoma cells. Although ARG was a relatively poor mitogen for Balb/c3T3 cells in comparison to HB-EGF, it was similar in potency to HB-EGF in stimulating human prostate epithelial cell growth, suggesting that prostate epithelia may be a physiologic target for ARG in vivo. Expression of both ARG and HB-EGF mRNAs was induced in cultured prostate SMC by fibroblast growth factor-2, a human prostate SMC mitogen linked to prostate disease. These findings indicate that ARG and HB-EGF are likely to be key mediators of directional signaling between SMC and epithelial cells in the human prostate and appear to be coordinately regulated.

The effects of sustained hydrostatic pressure on select bladder smooth muscle cell functions

PURPOSE

Normal bladder development is believed to depend on the active work of the bladder for storing and expelling urine. When high urinary diversion is performed in infants and the bladder no longer undergoes normal filling, bladder development may be altered, ultimately resulting in bladder dysfunction. To help better understand this relationship of bladder function with growth at the cellular level we developed a novel laboratory method for applying hydrostatic pressure to cell cultures, and we characterized the response of neonatal bladder smooth muscle cells to physiological levels of sustained hydrostatic pressure.

MATERIALS AND METHODS

Neonatal ovine smooth muscle cells staining positive for desmin and alpha-smooth muscle actin were exposed to pressures of 0.3 (controls), 2, 4, 6 and 8.5 cm. water for 1, 3, 5 and 7 days. At the end of the experiments the cells were fixed, stained and counted. Mitogenic activity of the supernatant media from bladder smooth muscle cells exposed to 8.5 cm. water for 5 days (conditioned media) was tested before and after treatments of heating, freezing, passing through a heparin-sepharose affinity chromatography column or after the addition of suramin, a nonspecific growth factor inhibitor. Statistical analysis was performed using Student's t test with p <0.05 considered statistically significant.

RESULTS

Exposure of bladder smooth muscle cells to sustained hydrostatic pressures of 4, 6 and 8.5 cm. water resulted in increased cell proliferation. Differences became statistically significant (p <0.05) by day 5. Also, conditioned media contained mitogenic activity that was ablated by heating, freezing, passage through a heparin-sepharose affinity chromatography column or with the addition of suramin.

CONCLUSIONS

We have demonstrated a proliferative response of neonatal bladder smooth muscle after exposure to physiological levels of sustained hydrostatic pressure. This response is partially due to 1 or more transferable mitogenic factors. These data support the hypothesis that pressure associated with bladder filling is an important stimulus for detrusor development.

Heparin-binding EGF-like growth factor expression increases selectively in bladder smooth muscle in response to lower urinary tract obstruction

Heparin-binding epidermal growth factor-like growth factor (HB-EGF), an activating ligand for the epidermal growth factor receptor (ErbB1) tyrosine kinase and at least one isoform of the ErbB4 receptor tyrosine kinase, is synthesized by the smooth muscle of the human bladder wall. In this study we tested the hypothesis that HB-EGF plays a role in the bladder-wall thickening that occurs in response to obstructive syndromes affecting the lower urinary tract, possibly by acting as an autocrine smooth muscle cell (SMC) growth factor. HB-EGF was mitogenic for primary culture human bladder SMC, and cell growth in serum-containing medium was inhibited more than 70% by [Glu52]-diphtheria toxin/CRM197, a specific HB-EGF inhibitor, consistent with a physiologic role for HB-EGF as an autocrine bladder SMC mitogen. Human and mouse bladder SMC in vivo and cultured human bladder SMC expressed the primary HB-EGF receptor, ErbB1, but not mRNA for the secondary HB-EGF receptor, ErbB4, thereby identifying ErbB1 as the cognate HB-EGF receptor in the bladder wall. Reverse transcription-polymerase chain reaction analysis also demonstrated ErbB2 and ErbB3 expression in human bladder muscle tissue, suggesting the possibility of receptor cross-talk after ErbB1 activation. Urethral ligation in mice resulted in an increase in steady-state HB-EGF mRNA expression up to 24 hours in whole bladder tissue in comparison with ErbB1 and glyceraldehyde 3-phosphate dehydrogenase mRNA levels, which did not change in a demonstrable pattern. HB-EGF protein increased coordinately with HB-EGF mRNA levels. Dissection of bladder tissue into muscle and mucosal layers demonstrated that the increase in HB-EGF mRNA occurred predominantly in the muscle layer, with peak levels (13-fold higher than sham controls) occurring 12 hours after obstruction. These data support a physiologic role for HB-EGF as a mediator of hypertrophic bladder tissue growth.

The dare gene: steroid hormone production, olfactory behavior, and neural degeneration in Drosophila

Steroid hormones mediate a wide variety of developmental and physiological events in insects, yet little is known about the genetics of insect steroid hormone biosynthesis. Here we describe the Drosophila dare gene, which encodes adrenodoxin reductase (AR). In mammals, AR plays a key role in the synthesis of all steroid hormones. Null mutants of dare undergo developmental arrest during the second larval instar or at the second larval molt, and dare mutants of intermediate severity are delayed in pupariation. These defects are rescued to a high degree by feeding mutant larvae the insect steroid hormone 20-hydroxyecdysone. These data, together with the abundant expression of dare in the two principal steroid biosynthetic tissues, the ring gland and the ovary, argue strongly for a role of dare in steroid hormone production. dare is the first Drosophila gene shown to encode a defined component of the steroid hormone biosynthetic cascade and therefore provides a new tool for the analysis of steroid hormone function. We have explored its role in the adult nervous system and found two striking phenotypes not previously described in mutants affected in steroid hormone signaling. First, we show that mild reductions of dare expression cause abnormal behavioral responses to olfactory stimuli, indicating a requirement for dare in sensory behavior. Then we show that dare mutations of intermediate strength result in rapid, widespread degeneration of the adult nervous system.

Ecdysone response genes govern egg chamber development during mid-oogenesis in Drosophila

The steroid hormone ecdysone regulates larval development and metamorphosis in Drosophila melanogaster through a complex genetic hierarchy that begins with a small set of early response genes. Here, we present data indicating that the ecdysone response hierarchy also mediates egg chamber maturation during mid-oogenesis. E75, E74 and BR-C are expressed in a stage-specific manner while EcR expression is ubiquitous throughout oogenesis. Decreasing or increasing the ovarian ecdysone titer using a temperature-sensitive mutation or exogenous ecdysone results in corresponding changes in early gene expression. The stage 10 follicle cell expression of E75 in wild-type, K10 and EGF receptor (Egfr) mutant egg chambers reveals regulation of E75 by both the Egfr and ecdysone signaling pathways. Genetic analysis indicates a germline requirement for ecdysone-responsive gene expression. Germline clones of E75 mutations arrest and degenerate during mid-oogenesis and EcR germline clones exhibit a similar phenotype, demonstrating a functional requirement for ecdysone responsiveness during the vitellogenic phase of oogenesis. Finally, the expression of Drosophila Adrenodoxin Reductase increases during mid-oogenesis and clonal analysis confirms that this steroidogenic enzyme is required in the germline for egg chamber development. Together these data suggest that the temporal expression profile of E75, E74 and BR-C may be a functional reflection of ecdysone levels and that ecdysone provides temporal signals regulating the progression of oogenesis and proper specification of dorsal follicle cell fates.

Oxybutynin chloride inhibits proliferation and suppresses gene expression in bladder smooth muscle cells

PURPOSE

We test the hypothesis that oxybutynin chloride inhibits bladder smooth muscle cell proliferation.

MATERIALS AND METHODS

Cultured rat bladder smooth muscle cells were grown in Medium 199 supplemented with 10% fetal bovine serum in the presence of 0, 1, 10 and 100 microM. oxybutynin. Cell proliferation was assessed by counting cell numbers 48 and 96 hours after plating. To investigate the role of oxybutynin in bladder smooth muscle cell proliferation after mechanical stretch, cells were grown on silicone elastomer bottomed culture plates and subjected to cyclical stretch-relaxation for 48 hours in the presence of 10 microM. oxybutynin. Deoxyribonucleic acid synthesis was assessed by tritiated thymidine incorporation assay. To examine the effect of oxybutynin on stretch activated gene expression, bladder smooth muscle cells were subjected to stretch-relaxation for 2 hours with and without 10 microM. oxybutynin, and relative c-jun messenger (m) ribonucleic acid (RNA) levels were assessed by semiquantitative reverse transcriptase-polymerase chain reaction with normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.

RESULTS

The serum stimulated increase in bladder smooth muscle cell growth was inhibited by oxybutynin in a dose dependent manner. In bladder smooth muscle cells there was a 4.7-fold increase in deoxyribonucleic acid synthesis after mechanical stretch, which decreased by 40% (p <0.01) when cells were stretched in the presence of oxybutynin. Stretch stimulated significant increase in c-jun mNRA levels, which was significantly decreased by oxybutynin.

CONCLUSIONS

Oxybutynin chloride inhibits bladder smooth muscle cell proliferation induced by serum and mechanical stretch. A potential mechanism by which oxybutynin inhibits proliferation may be the down regulation of growth promoting genes, such as c-jun. We speculate that oxybutynin may be useful for preventing permanent hypertrophic bladder changes in addition to decreasing intravesical pressure.

Plasma levels of vascular endothelial growth factor are increased in patients with metastatic prostate cancer

OBJECTIVES

Vascular endothelial growth factor (VEGF) is a cytokine that plays an important role in tumor angiogenesis. VEGF is overexpressed in many human cancers, including prostate cancer, but circulating levels of VEGF in patients with prostate cancer have not been reported. In this study, we analyzed plasma concentrations of VEGF in a cohort of patients with prostate cancer and compared them with a normal population.

METHODS

Twenty-six healthy, cancer-free individuals and 80 patients with prostate cancer (54 patients with localized prostate cancer and 26 patients with metastatic prostate cancer [bone or lymph node positive]) were analyzed in this study. Blood was drawn in the same fashion from all individuals and deposited in tubes containing ethylenediaminetetraacetic acid as anticoagulant. Plasma was extracted and VEGF concentrations were determined using a quantitative sandwich enzyme immunoassay technique.

RESULTS

Median plasma VEGF was 28.5 pg/mL (interquartile range 19.3 to 57.0) in patients with metastases; 7.0 pg/mL (interquartile range 0 to 26.5) in patients with localized disease, and 0 pg/mL (interquartile range 0 to 24) in controls. These differences were statistically significant (P <0.001). When compared group by group, the metastatic group had significantly higher plasma VEGF than the localized disease group and the control group (P = 0.003 and P <0.001, respectively). There was a tendency for plasma VEGF to be higher in the localized disease group than in the control group, a trend that almost reached statistical significance (P = 0.038). Using a cutoff of 18 pg/mL, the sensitivity and specificity of the test in differentiating between patients with and without metastatic disease was 81% and 71%, respectively. The odds of metastatic disease were almost 10 times greater for patients with VEGF values greater than 18 pg/mL than for those with values less than 18 pg/mL. There was no correlation between age and plasma VEGF values or between plasma VEGF and serum prostate-specific antigen (PSA). However, patients with serum PSA greater than 20 ng/mL had significantly higher plasma VEGF values than patients with serum PSA less than 20 ng/mL (P <0.001). No direct relation was found between Gleason sum and plasma VEGF, although VEGF levels were higher in patients with Gleason sums of 8 to 10 than in patients with lower Gleason sums.

CONCLUSIONS

Our study indicates that patients with metastatic prostate cancer have higher plasma VEGF levels than patients with localized disease or healthy controls. A larger prospective study is needed to confirm the predictive utility of VEGF.

Oxybutynin chloride inhibits proliferation and suppresses gene expression in bladder smooth muscle cells

PURPOSE

We test the hypothesis that oxybutynin chloride inhibits bladder smooth muscle cell proliferation.

MATERIALS AND METHODS

Cultured rat bladder smooth muscle cells were grown in Medium 199 supplemented with 10% fetal bovine serum in the presence of 0, 1, 10 and 100 microM. oxybutynin. Cell proliferation was assessed by counting cell numbers 48 and 96 hours after plating. To investigate the role of oxybutynin in bladder smooth muscle cell proliferation after mechanical stretch, cells were grown on silicone elastomer bottomed culture plates and subjected to cyclical stretch-relaxation for 48 hours in the presence of 10 microM. oxybutynin. Deoxyribonucleic acid synthesis was assessed by tritiated thymidine incorporation assay. To examine the effect of oxybutynin on stretch activated gene expression, bladder smooth muscle cells were subjected to stretch-relaxation for 2 hours with and without 10 microM. oxybutynin, and relative c-jun messenger (m) ribonucleic acid (RNA) levels were assessed by semiquantitative reverse transcriptase-polymerase chain reaction with normalization to glyceraldehyde-3-phosphate dehydrogenase mRNA levels.

RESULTS

The serum stimulated increase in bladder smooth muscle cell growth was inhibited by oxybutynin in a dose dependent manner. In bladder smooth muscle cells there was a 4.7-fold increase in deoxyribonucleic acid synthesis after mechanical stretch, which decreased by 40% (p <0.01) when cells were stretched in the presence of oxybutynin. Stretch stimulated significant increase in c-jun mNRA levels, which was significantly decreased by oxybutynin.

CONCLUSIONS

Oxybutynin chloride inhibits bladder smooth muscle cell proliferation induced by serum and mechanical stretch. A potential mechanism by which oxybutynin inhibits proliferation may be the down regulation of growth promoting genes, such as c-jun. We speculate that oxybutynin may be useful for preventing permanent hypertrophic bladder changes in addition to decreasing intravesical pressure.

AP-1 mediates stretch-induced expression of HB-EGF in bladder smooth muscle cells

Mechanical induction of growth factor synthesis may mediate adaptive responses of smooth muscle cells (SMC) to increases in physical load. We previously demonstrated that cyclic mechanical stretch induces expression of the SMC, fibroblast, and epithelial cell mitogen heparin-binding epidermal growth factor-like growth factor (HB-EGF) in bladder SMC, an observation that suggests that this growth factor may be involved in compensatory bladder hypertrophy. In the present study we provide evidence that the activator protein-1 (AP-1) transcription factor plays a critical role in this mechanoinduction process. Rat bladder SMC were transiently transfected with a series of 5' deletion mutants of a promoter-reporter construct containing 1. 7 kb of the mouse HB-EGF promoter that was previously shown to be stretch responsive. The stretch-mediated increase in promoter activity was completely ablated with deletion of nucleotide positions -1301 to -881. Binding of AP-1, as evaluated by electrophoretic mobility shift assay, to a synthetic oligonucleotide containing an AP-1 binding site increased in response to stretch, and binding was inhibited by excess unlabeled DNA corresponding to nucleotides -993 to -973 from the HB-EGF promoter, a region that contains a previously recognized composite AP-1/Ets site. Stretch-induced promoter activity was significantly inhibited by site-directed mutagenesis of the AP-1 or Ets components of this site. Consistent with the promoter and gel-shift studies, curcumin, an inhibitor of AP-1 activation, suppressed the HB-EGF mRNA induction after stretch. Stretch also specifically increased mRNA levels for matrix metalloproteinase (MMP)-1, the promoter of which contains a functional AP-1 element, but not for MMP-2, the promoter of which does not contain an AP-1 element. The stretch response of the MMP-1 gene was also completely inhibited by curcumin. Collectively, these findings indicate that AP-1-mediated transcription plays an important role in the regulation of gene expression in bladder muscle in response to mechanical forces.