Is posterior compartment prolapse associated with anal incontinence?

OBJECTIVE

It has been claimed that manifestations of posterior compartment prolapse, such as rectocele, enterocele and intussusception, are associated with anal incontinence (AI), but this has not been studied while controlling for anal sphincter trauma. We aimed to investigate this association in women with intact anal sphincter presenting with pelvic floor dysfunction.

METHODS

This retrospective study analyzed 1133 women with intact anal sphincter presenting to a tertiary urogynecological center for pelvic floor dysfunction between 2014 and 2016. All women underwent a standardized interview, including assessment of symptoms of AI, clinical examination and three-/four-dimensional transperineal ultrasound. Descent of the rectal ampulla, true rectocele, enterocele, intussusception and anal sphincter trauma were diagnosed offline.

RESULTS

Mean age was 54.1 (range, 17.6-89.7) years and mean body mass index was 29.4 (range, 14.7-67.8) kg/m2 . AI was reported by 149 (13%) patients, with a median St Mark's anal incontinence score of 12 (interquartile range, 1-23). Significant posterior compartment prolapse was seen in 693 (61%) women on clinical examination. Overall, 638 (56%) women had posterior compartment prolapse on imaging: 527 (47%) had a true rectocele, 89 (7.9%) had an enterocele and 26 (2.3%) had an intussusception. Women with ultrasound-diagnosed enterocele had a significantly higher rate of AI (23.6% vs 12.3%; odds ratio (OR), 2.21 (95% CI, 1.31-3.72); P = 0.002), but when adjusted for potential confounders, this association was no longer significant (OR, 1.56 (95% CI, 0.82-2.77); P = 0.134).

CONCLUSION

In women without anal sphincter trauma, posterior compartment prolapse, whether diagnosed clinically or by imaging, was not shown to be associated with AI. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

To blunt or not to blunt: Still an outlawed practice in peripheral nerve blocks?

Probably the first published account of regional nerve blocks was by Gaston Labat in 1922. Since the earlier experimentation, regional anesthesia has seen many ups and downs. The concept of field anesthesia popularized by the military anesthesiologists to be used in the battlefields, was quickly picked up by their colleagues working in the civil hospitals. The real breakthrough was brought about the invention of block needles to be used specifically for the peripheral nerve blocks, and proved to be safer than ordinary hypodermic syringe needles. The block needles, however, come at a higher price and the availability remains a constant problem, especially in the remote places of the low-income countries. The next revolution came with the advent of nerve stimulator and the ultrasound in the block techniques. Both of these developments really revolutionized the art of regional anesthesia. The authors describe a technique of use of blunted stylets of the ordinary intravenous cannulas. The technique can be used if resources are scarce, and with proper sterilization. Key words: Cannula stylets; Blunting; Peripheral nerve blocks; Ultrasound-guided; COVID-19 Citation: Munasinghe BM, Subramaniam N. To blunt or not to blunt: Still an outlawed practice in peripheral nerve blocks? Anaesth. pain intensive care 2022;26(3):391-393. DOI: 10.35975/apic.v26i3.1913 Received: March 30, 2022; Reviewed: April 22, 2022; Accepted: May 05, 2022

Location of obstetric anal sphincter injury scars on translabial tomographic ultrasound

OBJECTIVE

Obstetric anal sphincter injury (OASI) is a common preventable cause of anal incontinence. Both diagnosis and primary repair of OASI are often suboptimal, partly owing to the absence of effective clinical audit. The aim of this study was to evaluate the location of scars or defects of the external anal sphincter (EAS), diagnosed by translabial ultrasound (TLUS), following primary OASI repair.

METHODS

This was a retrospective analysis of 309 women who were seen at a tertiary obstetric unit after primary repair of OASI between June 2012 and May 2019. All women underwent a standardized interview, including St Mark's incontinence score, followed by clinical examination and TLUS assessment within 2-9 months after OASI repair. Postprocessing of TLUS volume datasets was performed by an investigator who was blinded to all other information. Tomographic ultrasound imaging was used to evaluate the presence of a scar or defect in the proximal and distal parts of the EAS. Women were classified into four groups according to the imaging findings: (1) no visible defect or distortion (likely false positive); (2) only proximal OASI; (3) only distal OASI; and (4) both proximal and distal OASI.

RESULTS

Of the 309 women seen during the study period, 34 were excluded because they were referred for reasons other than recent (< 1 year) OASI, 16 owing to missing data and four owing to poor image quality, leaving 255 patients for analysis. Women were seen on average 0.25 ± 0.1 years after the index birth, and their mean age at delivery was 29.1 ± 4.6 years. Anal incontinence was reported by 97 (38.0%) women. A scar or defect was seen only in the proximal part of the EAS in 64 (25.1%) women and only in the distal part in 19 (7.5%) (P < 0.001). In 165 (64.7%) women, the damage affected both the proximal and distal EAS.

CONCLUSIONS

EAS scars after primary OASI repair commonly affect the entire length of the EAS; however, partial tears seem to be more likely to occur proximally. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Modelling the impact of lockdown-easing measures on cumulative COVID-19 cases and deaths in England

OBJECTIVES

To assess the potential impacts of successive lockdown-easing measures in England, at a point in the COVID-19 pandemic when community transmission levels were relatively high.

DESIGN

We developed a Bayesian model to infer incident cases and reproduction number (R) in England, from incident death data. We then used this to forecast excess cases and deaths in multiple plausible scenarios in which R increases at one or more time points.

SETTING

England.

PARTICIPANTS

Publicly available national incident death data for COVID-19 were examined.

PRIMARY OUTCOME

Excess cumulative cases and deaths forecast at 90 days, in simulated scenarios of plausible increases in R after successive easing of lockdown in England, compared with a baseline scenario where R remained constant.

RESULTS

Our model inferred an R of 0.75 on 13 May when England first started easing lockdown. In the most conservative scenario modelled where R increased to 0.80 as lockdown was eased further on 1 June and then remained constant, the model predicted an excess 257 (95% CI 108 to 492) deaths and 26 447 (95% CI 11 105 to 50 549) cumulative cases over 90 days. In the scenario with maximal increases in R (but staying ≤1), the model predicts 3174 (95% CI 1334 to 6060) excess cumulative deaths and 421 310 (95% CI 177 012 to 804 811) cases. Observed data from the forecasting period aligned most closely to the scenario in which R increased to 0.85 on 1 June, and 0.9 on 4 July.

CONCLUSIONS

When levels of transmission are high, even small changes in R with easing of lockdown can have significant impacts on expected cases and deaths, even if R remains ≤1. This will have a major impact on population health, tracing systems and healthcare services in England. Following an elimination strategy rather than one of maintenance of R ≤1 would substantially mitigate the impact of the COVID-19 epidemic within England.

Does exclusion of subcutaneous external anal sphincter on exoanal imaging matter?

OBJECTIVE

There is some speculation that an intact distal anal sphincter complex is of decisive importance for continence, although the external anal sphincter (EAS) is considered to be a single functional and anatomical entity. On tomographic translabial ultrasound (TLUS), the caudal slice at the level of the subcutaneous EAS is currently omitted from the diagnostic algorithm due to the prevalence of artifact at that level. The aim of this study was to determine the predictive value of assessment of the subcutaneous EAS on tomographic TLUS for anal incontinence (AI).

METHODS

This was a retrospective study of 463 women seen at our urogynecological service in 2015. All underwent a standardized questionnaire, including determination of St Mark's incontinence score (SMIS), clinical examination and three-/four-dimensional TLUS. On tomographic TLUS, EAS defect angles in slices one to seven were measured on maximum pelvic floor muscle contraction. A slice was defined as positive for a defect if the defect angle was ≥ 30°. The association between significant subcutaneous EAS trauma (i.e. defect angle of ≥ 30° in slice seven) and symptoms of AI, symptom bother score and SMIS was assessed. The performances of the standard six-slice model and the seven-slice model, including the subcutaneous EAS, in the prediction of AI were compared.

RESULTS

While there was a highly significant association between all measures of AI and significant EAS trauma in slice seven, addition of the seventh slice to the existing six-slice model did not improve the predictive value for AI.

CONCLUSION

As inclusion of the subcutaneous slice of the EAS on tomographic TLUS does not seem to improve the predictive value for AI, the current methodology for assessment of EAS trauma on tomographic TLUS can remain unchanged. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Cannabis-Associated Psychotic-like Experiences Are Mediated by Developmental Changes in the Parahippocampal Gyrus

OBJECTIVE

Cannabis consumption during adolescence has been reported as a risk factor for psychotic-like experiences (PLEs) and schizophrenia. However, brain developmental processes associated with cannabis-related PLEs are still poorly described.

METHOD

A total of 706 adolescents from the general population who were recruited by the IMAGEN consortium had structural magnetic resonance imaging scans at both 14 and 19 years of age. We used deformation-based morphometry to map voxelwise brain changes between the two time points, using the pairwise algorithm in SPM12b. We used an a priori region-of-interest approach focusing on the hippocampus/parahippocampus to perform voxelwise linear regressions. Lifetime cannabis consumption was assessed using the European School Survey Project on Alcohol and other Drugs (ESPAD), and PLEs were assessed with the Comprehensive Assessment Psychotic-like experiences (CAPE) tool. We first tested whether hippocampus/parahippocampus development was associated with PLEs. Then we formulated and tested an a priori simple mediation model in which uncus development mediates the association between lifetime cannabis consumption and PLEs.

RESULTS

We found that PLEs were associated with reduced expansion within a specific region of the right hippocampus/parahippocampus formation, the uncus (p = .002 at the cluster level, p = .018 at the peak level). The partial simple mediation model revealed a significant total effect from lifetime cannabis consumption to PLEs (b = 0.069, 95% CI = 0.04-0.1, p =2 × 10^-16), as well as a small yet significant, indirect effect of right uncus development (0.004; 95% CI = 0.0004-0.01, p = .026).

CONCLUSION

We show here that the uncus development is involved in the cerebral basis of PLEs in a population-based sample of healthy adolescents.

What is a significant defect of the anal sphincter on translabial ultrasound?

OBJECTIVE

The anal sphincter is commonly evaluated with endoanal ultrasound. Recently, translabial ultrasound imaging has been proposed for sphincter imaging, with moderate to good correlation between the methods. An endosonographic defect is defined as one with a radial extension of > 30° in at least two-thirds of the length of the anal sphincter. This is equivalent to defining significant anal sphincter trauma on translabial tomographic ultrasound imaging (TUI) as a defect in at least four of six slices, a definition which has been validated. This study was designed to validate a residual defect angle of > 30° for the definition of significant anal sphincter trauma on translabial ultrasound.

METHODS

This was a retrospective study involving 399 women attending a tertiary urogynecology unit in 2014. All underwent a standardized interview, including determination of St Mark's fecal incontinence score (SMIS), clinical examination and 3D/4D translabial ultrasound examination with the woman at rest and on pelvic floor muscle contraction (PFMC). External (EAS) and internal (IAS) anal sphincter defect angles were measured in individual TUI slices and associations with anal incontinence symptoms, bother score and SMIS were analyzed.

RESULTS

There were weak but significant correlations of anal incontinence symptoms, bother score and SMIS with EAS and IAS defect angle, measured on images acquired with the woman at rest and on PFMC. The predictive value of single-slice defect angle on TUI was low, and areas under the receiver-operating-characteristics curves were too low to determine a distinct cut-off value for defect angle.

CONCLUSIONS

Anal sphincter residual defects on single translabial TUI slices are weakly associated with measures of anal incontinence. Single-slice defect angle is too poor a predictor to allow validation of the 30° defect angle cut-off used in endoanal ultrasound. Larger studies in populations with a higher prevalence of anal incontinence are needed before we can disregard anal sphincter defects smaller than 30° on translabial ultrasound. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Neural Correlates of Failed Inhibitory Control as an Early Marker of Disordered Eating in Adolescents

BACKGROUND

Binge eating and other forms of disordered eating behavior (DEB) are associated with failed inhibitory control. This study investigated the neural correlates of failed inhibitory control as a potential biomarker for DEB.

METHODS

The study used prospective longitudinal data from the European IMAGEN study adolescent cohort. Participants completed baseline assessments (questionnaires and a brain scan [functional magnetic resonance imaging]) at 14 years of age and a follow-up assessment (questionnaires) at 16 years of age. Self-reported binge eating and/or purging were used to indicate presence of DEB. Neural correlates of failed inhibition were assessed using the stop signal task. Participants were categorized as healthy control subjects (reported no DEB at both time points), maintainers (reported DEB at both time points), recoverers (reported DEB at baseline only), and developers (reported DEB at follow-up only). Forty-three individuals per group with complete scanning data were matched on gender, age, puberty, and intelligence (N = 172).

RESULTS

At baseline, despite similar task performance, incorrectly responding to stop signals (failed inhibitory control) was associated with greater recruitment of the medial prefrontal cortex and anterior cingulate cortex in the developers compared with healthy control subjects and recoverers.

CONCLUSIONS

Greater recruitment of the medial prefrontal and anterior cingulate regions during failed inhibition accords with abnormal evaluation of errors contributing to DEB development. As this precedes symptom onset and is evident despite normal task performance, neural responses during failed inhibition may be a useful biomarker of vulnerability for DEB. This study highlights the potential value of prospective neuroimaging studies for identifying markers of illness before the emergence of behavior changes.

How repeatable is assessment of external anal sphincter trauma by exoanal 4D ultrasound?

OBJECTIVE

Three-/four-dimensional translabial ultrasound (TLUS) is gaining popularity for the assessment of anal sphincter trauma, although repeatability data are lacking. This study aimed to determine the repeatability of tomographic ultrasound imaging (TUI) on TLUS for the diagnosis of external anal sphincter (EAS) trauma and compare the performance of a novice with that of an experienced investigator.

METHODS

This was a retrospective study of archived ultrasound datasets of patients who presented with symptoms of pelvic floor dysfunction and were examined twice between 2012 and 2016 at an average interval of 260 (range, 1-1100) days. All volumes were obtained using a GE Medical Systems Voluson 730 Expert or E8 ultrasound system. Post-processing of volumes was performed independently by two investigators, one with over 1 year's experience and another with no prior experience in using TUI, who were blinded to clinical data, each other's results and the results obtained at the first timepoint. Significant trauma on EAS was diagnosed if four of the six TUI slices showed a defect of ≥ 30°. Intra- and interobserver agreement were determined using Cohen's kappa (κ) and intraclass correlation coefficients.

RESULTS

During the study period, 105 women underwent two TLUS assessments of the anal sphincter. Of these, 103 patients with ultrasound volumes available for both timepoints were included in the analysis. The novice investigator demonstrated average repeatability for assessment of significant EAS trauma and single-slice defect (κ, 0.30 and 0.22, respectively) despite relatively high agreement between measurements obtained at the two timepoints (84.5% and 79.3%, respectively). The experienced investigator demonstrated good to very good repeatability for significant EAS trauma and single-slice defect (κ, 0.91 and 0.78, respectively) between the two assessments, which equates to 98.1% and 94.7% agreement, respectively.

CONCLUSION

The repeatability of TLUS measurements for diagnosis of EAS trauma seems to be very good when imaging is undertaken with state-of-the-art equipment and the analysis is performed by an experienced observer; however, the performance of a novice investigator is much poorer. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Impact of postoperative radiotherapy on survival and loco-regional control in node-negative oral cavity tumours classified as T3 using the AJCC Cancer Staging Manual eighth edition

According to the eighth edition of the AJCC Cancer Staging Manual (AJCC8), a depth of invasion (DOI) >10mm is classified as pT3, representing a locally advanced tumour requiring postoperative radiotherapy (PORT). When node-negative, however, evidence regarding whether PORT improves loco-regional control or survival is unclear. To clarify this, two cohorts of patients were studied: (1) patients classified as pT3N0 by the seventh edition of the AJCC manual (AJCC7), with DOI >10mm and a tumour diameter >4cm (17 patients who received PORT), and (2) patients classified as pT1N0 and pT2N0 by AJCC7, with DOI >10mm and a tumour diameter <4cm (55 patients who did not receive PORT). Loco-regional control and survival were analysed. PORT was found not to impact overall survival or disease-free survival. It was also found not to impact local, regional, or distant recurrence. Although the two subsets of patients considered here (DOI >10mm with tumour diameter below or above 4cm) were previously distinct, they are both considered pT3 in AJCC8. Data from this study indicate that the routine administration of PORT to patients with a DOI >10mm may not be warranted in the absence of other risk features such as nodal disease or close margins.

Studying food reward and motivation in humans

A key challenge in studying reward processing in humans is to go beyond subjective self-report measures and quantify different aspects of reward such as hedonics, motivation, and goal value in more objective ways. This is particularly relevant for the understanding of overeating and obesity as well as their potential treatments. In this paper are described a set of measures of food-related motivation using handgrip force as a motivational measure. These methods can be used to examine changes in food related motivation with metabolic (satiety) and pharmacological manipulations and can be used to evaluate interventions targeted at overeating and obesity. However to understand food-related decision making in the complex food environment it is essential to be able to ascertain the reward goal values that guide the decisions and behavioral choices that people make. These values are hidden but it is possible to ascertain them more objectively using metrics such as the willingness to pay and a method for this is described. Both these sets of methods provide quantitative measures of motivation and goal value that can be compared within and between individuals.

Neural and behavioral effects of a novel mu opioid receptor antagonist in binge-eating obese people

BACKGROUND

Binge eating is associated with obesity and has been conceptualized as "food addiction." However, this view has received only inconsistent support in humans, and limited evidence relates key neurocircuitry to the disorder. Moreover, relatively few studies have used pharmacologic functional magnetic resonance imaging to probe the underlying basis of altered eating behaviors.

METHODS

In a double-blind, placebo-controlled, parallel group study, we explored the effects of a potent mu-opioid receptor antagonist, GSK1521498, in obese individuals with moderate binge eating. Subjects were tested during a baseline placebo run-in period and retested after 28-days of drug (n = 21) or placebo (n = 21) treatment. Using functional magnetic resonance imaging and behavioral measures, we determined the drug's effects on brain responses to food images and, separately, on motivation to expend energy to view comparable images.

RESULTS

Compared with placebo, GSK1521498 was associated with a significant reduction in pallidum/putamen responses to pictures of high-calorie food and a reduction in motivation to view images of high-calorie food. Intriguingly, although motivational responding was reduced, subjective liking for the same images actually increased following drug treatment.

CONCLUSIONS

Stimulus-specific putamen/pallidal responses in obese people with binge eating are sensitive to altered mu-opioid function. This neuromodulation was accompanied by reductions in motivational responding, as measured by grip force, although subjective liking responses to the same stimuli actually increased. As well as providing evidence for a link between the opioid system and food-related behavior in binge-eating obese individuals, these results support a dissociation across measures of motivation and liking associated with food-related stimuli in these individuals.

Attribution of intentional causation influences the perception of observed movements: behavioral evidence and neural correlates

Recent research on human agency suggests that intentional causation is associated with a subjective compression in the temporal interval between actions and their effects. That is, intentional movements and their causal effects are perceived as closer together in time than equivalent unintentional movements and their causal effects. This so-called intentional binding effect is consistently found for one’s own self-generated actions. It has also been suggested that intentional binding occurs when observing intentional movements of others. However, this evidence is undermined by limitations of the paradigm used. In the current study we aimed to overcome these limitations using a more rigorous design in combination with functional Magnetic Resonance Imaging (fMRI) to explore the neural underpinnings of intentional binding of observed movements. In particular, we aimed to identify brain areas sensitive to the interaction between intentionality and causality attributed to the observed action. Our behavioral results confirmed the occurrence of intentional binding for observed movements using this more rigorous paradigm. Our fMRI results highlighted a collection of brain regions whose activity was sensitive to the interaction between intentionality and causation. Intriguingly, these brain regions have previously been implicated in the sense of agency over one’s own movements. We discuss the implications of these results for intentional binding specifically, and the sense of agency more generally.

Food images engage subliminal motivation to seek food

Human eating behaviour is motivated and shaped by a complex interaction of internal drives such as hunger, external influences such as environmental cues and the sensory properties of food itself. Thus, as is demonstrated by the example of sensory-specific satiety (SSS), hunger may be reduced but particular foods (for example, desserts) retain their attraction and their ability to prompt consumption. In considering consumption, and overconsumption, it is therefore important to understand the interaction between internal and external drives to eat. Using grip force as a measure of motivation, we examined this interaction using an SSS manipulation. Critically, we sought to determine whether food stimuli would exert their influence even when they were subliminally presented (and thus not accessible to consciousness), and whether this unconscious influence would be flexibly updated in response to changes in food reward value with satiety. Demonstrating that the SSS effect remains when external stimuli are not consciously perceived, our data highlight the importance of even the most subtle, fleeting and even subliminal external events in shaping our motivation towards food.

CamBAfx: Workflow Design, Implementation and Application for Neuroimaging

CamBAfx is a workflow application designed for both researchers who use workflows to process data (consumers) and those who design them (designers). It provides a front-end (user interface) optimized for data processing designed in a way familiar to consumers. The back-end uses a pipeline model to represent workflows since this is a common and useful metaphor used by designers and is easy to manipulate compared to other representations like programming scripts. As an Eclipse Rich Client Platform application, CamBAfx's pipelines and functions can be bundled with the software or downloaded post-installation. The user interface contains all the workflow facilities expected by consumers. Using the Eclipse Extension Mechanism designers are encouraged to customize CamBAfx for their own pipelines. CamBAfx wraps a workflow facility around neuroinformatics software without modification. CamBAfx's design, licensing and Eclipse Branding Mechanism allow it to be used as the user interface for other software, facilitating exchange of innovative computational tools between originating labs.

Development of a broadband picosecond infrared spectrometer and its incorporation into an existing ultrafast time-resolved resonance Raman, UV/visible, and fluorescence spectroscopic apparatus

We have constructed a broadband ultrafast time-resolved infrared (TRIR) spectrometer and incorporated it into our existing time-resolved spectroscopy apparatus, thus creating a single instrument capable of performing the complementary techniques of femto-/picosecond time-resolved resonance Raman (TR3), fluorescence, and UV/visible/infrared transient absorption spectroscopy. The TRIR spectrometer employs broadband (150 fs, approximately 150 cm(-1) FWHM) mid-infrared probe and reference pulses (generated by difference frequency mixing of near-infrared pulses in type I AgGaS2), which are dispersed over two 64-element linear infrared array detectors (HgCdTe). These are coupled via custom-built data acquisition electronics to a personal computer for data processing. This data acquisition system performs signal handling on a shot-by-shot basis at the 1 kHz repetition rate of the pulsed laser system. The combination of real-time signal processing and the ability to normalize each probe and reference pulse has enabled us to achieve a high sensitivity on the order of deltaOD approximately 10(-4) - 10(-5) with 1 min of acquisition time. We present preliminary picosecond TRIR studies using this spectrometer and also demonstrate how a combination of TRIR and TR3 spectroscopy can provide key information for the full elucidation of a photochemical process.

Ski-interacting protein interacts with Smad proteins to augment transforming growth factor-beta-dependent transcription

Transforming growth factor-beta (TGF-beta) signaling requires the action of Smad proteins in association with other DNA-binding factors and coactivator and corepressor proteins to modulate target gene transcription. Smad2 and Smad3 both associate with the c-Ski and Sno oncoproteins to repress transcription of Smad target genes via recruitment of a nuclear corepressor complex. Ski-interacting protein (SKIP), a nuclear hormone receptor coactivator, was examined as a possible modulator of transcriptional regulation of the TGF-beta-responsive promoter from the plasminogen activator inhibitor gene-1. SKIP augmented TGF-beta-dependent transactivation in contrast to Ski/Sno-dependent repression of this reporter. SKIP interacted with Smad2 and Smad3 proteins in vivo in yeast and in mammalian cells through a region of SKIP between amino acids 201-333. In vitro, deletion of the Mad homology domain 2 (MH2) domain of Smad3 abrogated SKIP binding, like Ski/Sno, but the MH2 domain of Smad3 alone was not sufficient for protein-protein interaction. Overexpression of SKIP partially overcame Ski/Sno-dependent repression, whereas Ski/Sno overexpression attenuated SKIP augmentation of TGF-beta-dependent transcription. Our results suggest a potential mechanism for transcriptional control of TGF-beta signaling that involves the opposing and competitive actions of SKIP and Smad MH2-interacting factors, such as Ski and/or Sno. Thus, SKIP appears to modulate both TGF-beta and nuclear hormone receptor signaling pathways.

Cross-talk between 1,25-dihydroxyvitamin D3 and transforming growth factor-beta signaling requires binding of VDR and Smad3 proteins to their cognate DNA recognition elements

1,25-Dihydroxyvitamin D(3) (vitamin D) and transforming growth factor-beta (TGF-beta) regulate diverse biological processes including cell proliferation and differentiation through modulation of the expression of target genes. Members of the Smad family of proteins function as effectors of TGF-beta signaling pathways whereas the vitamin D receptor (VDR) confers vitamin D signaling. We investigated the molecular mechanisms by which TGF-beta and vitamin D signaling pathways interact in the regulation of the human osteocalcin promoter. Synergistic activation of the osteocalcin gene promoter by TGF-beta and vitamin D was observed in transient transfection experiments. However, in contrast to a previous report by Yanagisawa, J., Yanagi, Y., Masuhiro, Y., Suzawa, M., Watanabe, M., Kashiwagi, K., Toriyabe, T., Kawabata, M., Miyazono, K., and Kato, S. (1999) Science, 283, 1317-1321, synergistic activation was not detectable when the osteocalcin vitamin D response element (VDRE) alone was linked to a heterologous promoter. Inclusion of the Smad binding elements (SBEs) with the VDRE in the heterologous promoter restored synergistic activation. Furthermore, this synergy was dependent on the spacing between VDRE and SBEs. The Smad3-Smad4 heterodimer was found to bind in gel shift assay to two distinct DNA segments of the osteocalcin promoter: -1030 to -989 (SBE3) and -418 to -349 (SBE1). Deletion of SBE1, which is proximal to the VDRE, but not the distal SBE3 in this promoter reporter abolished TGF-beta responsiveness and eliminated synergistic co-activation with vitamin D. Thus the molecular mechanism, whereby Smad3 and VDR mediate cross-talk between the TGF-beta and vitamin D signaling pathways, requires both a VDRE and a SBE located in close proximity to the target promoter.

Receptor interacting protein RIP140 inhibits both positive and negative gene regulation by glucocorticoids

Recent development in the field of gene regulation by nuclear receptors (NRs) have identified a role for cofactors in transcriptional control. While some of the NR-associated proteins serve as coactivators, the effect of the receptor interacting protein 140 (RIP140) on NR transcriptional responses is complex. In this report we have studied the effect of RIP140 on gene regulation by the glucocorticoid receptor (GR). We demonstrate that RIP140 antagonized all GR-mediated responses tested, which included activation through classical GRE, the synergistic effects of glucocorticoids on AP-1 and Pbx1/HOXB1 responsive elements, as well as gene repression through a negative GRE and cross-talk with NF-kappaB (RelA). This involved the ligand-binding domain of the GR and did not occur when the GR was bound to the antagonist RU486. The strong repressive effect of RIP140 was restricted to glucocorticoid-mediated responses in as much as it slightly increased signaling through the RelA and the Pit-1/Pbx proteins and only slightly repressed signaling through the Pbx1/HOXB1 and AP-1 proteins, excluding general squelching as a mechanism. Instead, this suggests that RIP140 acts as a direct inhibitor of GR function. In line with a direct effect of RIP140 on the GR, we demonstrate a GR-RIP140 interaction in vitro by a glutathione S-transferase-pull down assay. Furthermore, the repressive effect of RIP140 could partially be overcome by overexpression of the coactivator TIF2, which involved a competition between TIF2 and RIP140 for binding to the GR.

Glucocorticoids repress transcription from a negative glucocorticoid response element recognized by two homeodomain-containing proteins, Pbx and Oct-1

Several studies have established that the prolactin (PRL) gene is expressed not only in lactotrophs and somatotrophs of the anterior pituitary but, albeit to a lesser extent, in non-pituitary cells like human thymocytes, decidualized endometrium, mammary glands during lactation, and some human non-pituitary cell lines. Despite the requirement in the pituitary for the pituitary-specific transcription factor Pit-1/GHF-1 for PRL expression, the expression in non-pituitary cells occurs in the absence of Pit-1/GHF-1 and can be repressed by glucocorticoids. This prompted us to investigate the transcription factors in non-pituitary cells which are involved in controlling expression and glucocorticoid repression of a previously characterized negative glucocorticoid response element from the bovine prolactin gene (PRL3 nGRE). Here we have demonstrated that non-pituitary cells (COS-7 and mouse hepatoma Hepa1c1c7 cells) conferred increased expression via the PRL3 nGRE mainly because of the binding of the ubiquitously expressed POU-homeodomain-containing octamer transcription factor-1 (Oct-1) to an AT-rich sequence present in the PRL3 sequence. However, full transcriptional activity required the binding of a second ubiquitously expressed homeodomain-containing protein, Pbx, previously shown to bind cooperatively with several homeotic selector proteins. The Pbx binding site in the PRL3 nGRE, located just upstream of the Oct-1 binding site, showed a strong sequence similarity with known Pbx binding sites and bound Pbx with an affinity similar to that of other established Pbx target sequences. Interestingly, both Oct-1 and Pbx binding to the PRL3 nGRE were found to be required for glucocorticoid repression. Addition of in vitro translated glucocorticoid receptor DNA binding domain to the nuclear extract prevented Oct-1 and Pbx from binding to the PRL element. The involvement of the homeobox protein Pbx in glucocorticoid repression via an nGRE identifies a new role for this protein.

Studies on the mechanism of glucocorticoid-mediated repression from a negative glucocorticoid response element from the bovine prolactin gene

Several models for repression of transcription by glucocorticoid hormone, some of which involve so-called negative glucocorticoid response elements (nGRE), have been suggested. In the cases where nGREs are required, the glucocorticoid receptor (GR) is thought to bind to the nGRE and interfere with transcriptional activation by positively acting transactivating factors. We have studied an nGRE from the bovine prolactin gene promoter (PRL3), which increases basal expression from a heterologous promoter in rat pituitary cells (GH3) and is repressed by glucocorticoids. Two proteins in addition to the GR were identified in pituitary cells to bind specifically to the PRL3 nGRE, one of which was the pituitary-specific transcription factor Pit-1/GHF-1. A mutation in the PRL3 nGRE, which destroyed Pit-1/GHF-1 binding, totally abolished the increased basal expression as well as glucocorticoid repression in transfected GH3 cells. A mutation in the binding site for the second protein, termed XTF, partially impaired basal activity but totally abrogated glucocorticoid repression. The same mutation had no effect on GR binding to the PRL3 nGRE. Mixing experiments with whole-cell extracts containing overexpressed GR from COS cells decreased the binding of both Pit-1/GHF-1 and XTF to the PRL3 element. However, Pit-1/GHF-1 displacement from the PRL3 element by the GR required XTF binding. Furthermore, GR binding to the PRL3 nGRE was required for glucocorticoid repression to occur, because a mutation of the GR binding site abolished the glucocorticoid effect. Moreover, the PRL3 nGRE was found to contain only half a palindromic GRE, allowing only one GR moiety to contact the DNA. These data demonstrate that the PRL3 nGRE is composite in nature and that the ability of the GR to repress transactivation by displacement requires an intermediary factor, XTF.

Vacuum delivery at The Maternity Hospital Kuala Lumpur: a comparison of metal and silicone cups

OBJECTIVE

To compare the advantages and disadvantages of the New Bird metal cups and silicone cups in terms of maternal and foetal outcome. To study the adverse effects and factors associated with failed vacuum deliveries.

DESIGN

A prospective randomised study of all vacuum deliveries from 1 December 1991 to 31 April 1992. The Hanshin electrical vacuum pump was used.

SETTING

A large obstetric unit-The Maternity Hospital Kuala Lumpur (MHKL).

SUBJECTS

Seventy-two consecutive patients where vacuum deliveries were indicated. Forty had metal and 32 had silicone cups. Another 7 vacuum deliveries using the manual vacuum pump were excluded.

MAIN OUTCOME MEASURES

Success rate of vaginal delivery, birth canal injuries, post-partum haemorrhage, duration of hospital stay, Apgar score, foetal injuries (scalp-ecchymosis, haematomas) neonatal jaundice, the rate of special care nursery (SCN) admission and neonatal mortality rate.

RESULTS

Failure to deliver with silicone cups alone was 21.9% compared to 10% for metal cups alone. Material morbidities and serious foetal scalp injuries were almost the same in both cups. However, minor foetal scalp injuries were significantly lower with silicone cups. Maternal height and baby's weight had no independent predictive values for successful vacuum delivery. When the foetal head was palpable per abdomen, the failure rate was 54.5% compared to 8.2% when it was not. Failed vacuum deliveries were associated with increased maternal and foetal morbidities.

CONCLUSION

Silicone cups and metal cups can be equally dangerous to the baby. Although our sample size was small, we recommend that vacuum delivery be avoided if the foetal head is palpable per abdomen.

cDNA cloning and characterization of rat salivary glycoproteins. Novel members of the proline-rich-protein multigene families

The cDNAs for two glycoproteins, the 158-kDa submandibular glycoprotein (SGP158) and the 200-kDa parotid glycoprotein (PGP200), have been cloned from rat submandibular and parotid glands, respectively. Both cDNAs encode for identical proteins with repeating peptides -Asp-Gln-Gly-(Asn)-Gln-Thr-Gln-Pro-Arg-Pro-Pro-His-Pro-. A full-length cDNA encoding SGP158 was obtained using the strategy of anchor-PCR, and a full-length cDNA of PGP200 was prepared using RNA-PCR. Sequence analysis of the cDNAs revealed that SGP158 and PGP200 are identical proteins with 23 repeating peptides. Twenty-one peptides contain potential N-glycosylation sites and these two glycoproteins differ only in their glycosylation patterns. Southern-blot analysis showed that a single-copy gene encodes both mRNAs. PGP200 is constitutively expressed, but the synthesis of SGP158 is totally dependent upon treatment of animals with the beta-agonist isoproterenol. The first 106-nucleotide sequence of cDNAs for PGP200 and SGP158, which corresponds to the 5'-untranslated region and sequence encoding the signal peptide, is highly conserved when compared with proline-rich protein and glutamine-rich protein gene sequences. Based on the nucleotide sequences of exon I, a phylogenetic tree was constructed for 35 members of these multigene families. The tree fits with the generally recognized phylogeny of mammalian orders. We propose that exon I sequences of the proline-rich protein and glutamine-rich protein multigene families are relatively new and are possibly generated through exon shuffling during evolution.

A steroid hormone response unit in the late leader of the noncoding control region of the human polyomavirus BK confers enhanced host cell permissivity

The effect of steroid hormones on multiplication of the human polyomavirus BK (BKV) was studied. Physiological concentrations of the synthetic glucocorticoid dexamethasone, progesterone R5020, or estrogen 17 beta-estradiol enhanced the permissivity of the host cell for BKV, resulting in an up to 11-fold (dexamethasone), 5-fold (progesterone), or 3-fold (17 beta-estradiol) higher virus yield. The increase in virus yield in dexamethasone-stimulated cells correlated with enhanced steady-state levels of viral transcripts. The late leader sequence of the BKV control region contains a hormone response unit composed of a nonconsensus glucocorticoid and/or progesterone response element (GRE/PRE) and a fully consensus estrogen response element (ERE). DNA-protein binding studies showed that the glucocorticoid receptor and the progesterone receptor bound to this BKV GRE/PRE-like sequence, while the estrogen receptor could bind to the BKV ERE motif. By transient transfection assays, we were able to show that these sequences can mediate steroid hormone-induced gene expression. However, no cooperative transactivation effect between the BKV GRE/PRE-like motif and BKV ERE motif was observed. This BKV hormone response unit may play an important role in vivo by enhancing a productive BKV infection, and perhaps also by reactivating a latent infection, during physiological or pathological conditions accompanied by increased steroid hormone levels.

Frozen section diagnosis in ophthalmic pathology

Frozen section diagnosis is extensively used in various branches of pathology, but its application in ophthalmic pathology was recognised only in the 1970s. We studied 10 sections of ocular and adenexal lesions by frozen section diagnosis, which included orbital lesions (4 cases), lid lesions (3 cases), and intraocular tissue (1 case). The time taken for processing ranged between 10 to 15 minutes. Diagnoses based on frozen section evaluation included lymphoma, mesenchymal chondrosarcoma, solar keratosis, compound naevus, silicone oil globules in cataractous lens, neurofibromatosis, pseudotumour, retinoblastoma, and chronic blepharitis. Although further histopathologic examination correlated well with the frozen section (100%) observations, the diagnosis was deferred in the case of naevus and reactive lymphoid hyperplasia. Our study shows that frozen section diagnosis in ophthalmic surgery is quite reliable and is particularly useful in ocular adenexal lesions.

The c-fos cAMP-response element: regulation of gene expression by a beta 2-adrenergic agonist, serum and DNA methylation

The transcription control region of the proto-oncogene c-fos contains multiple cis-acting elements to which specific trans-acting factors bind. One such well-studied binding motif in the c-fos promoter is the major cyclic AMP response element (CRE) TGACGT located at -62/-57. In this study we investigated the role of this element in gene regulation by beta 2-adrenergic/adenylate cyclase signalling and DNA methylation. By transient gene expression assays we were able to show that the c-fos regulatory sequences spanning nucleotides -361 to +13 could mediate gene expression by the beta 2-adrenergic agonist isoproterenol and the phosphodiesterase inhibitor theophylline. For isoproterenol however, a stimulating effect was observed in serum-starved cells, while an inhibitory effect was measured in cells supplemented with serum. The gene regulation by the cAMP elevating agents could be due, at least partially, to the major CRE since this isolated motif mediated gene expression by these drugs. Distinct protein-DNA complexes were obtained with nuclear extracts prepared from cells exposed to isoproterenol or/and theophylline under different serum conditions. We further show that DNA methylation of this CRE may also be involved in gene regulation as methylation of the CRE motif strongly reduced the binding of nuclear proteins.

Cognitive style as a factor in accounting students' perceptions of career-choice factors

Since prior studies of individuals' perceptions of career-choice factors have not considered the effect of cognitive styles of subjects, this study, using 68 accounting students, investigated the mediating effects of the field dependent-independent cognitive dimension on perceptions of the importance of career-choice factors. The results, in general, show that cognitive style affected individuals' perceptions of career-choice factors, suggesting that future studies of individuals' perceptions should take into account individual cognitive differences.