Attitudes of women with gestational diabetes toward diet and exercise: a qualitative study

OBJECTIVE

Gestational diabetes (GDM) refers to glucose intolerance of varying severity first occurring in pregnancy. Following a diagnosis of GDM, exercise and dietary modification has a positive effect on improving glycemic control. Lifestyle changes affected in pregnancies affected by GDM have beneficial effects on long-term health if continued following birth. In addition, the psychological impact of a diagnosis of GDM should not be overlooked. Reports of maternal stress, anxiety, and fear are commonly reported issues in the literature. Support, both socially and from health care professionals, is also linked with higher rates of success in GDM management. Research to date had focused on women's reaction to a diagnosis of GDM, their mood and quality of life following a diagnosis, and their knowledge or opinions on the management of GDM. This qualitative study explored the attitudes of women with GDM toward these lifestyle changes, specifically diet and exercise. Women were also asked to identify advice that would be useful for other women newly diagnosed with GDM.

METHODS

With ethical approval a qualitative study was conducted using semi-structured interviews which were examined using Thematic Analysis. Patients were invited to participate and gave written consent after a discussion with a study researcher. The question plan for semi-structured interviews was designed with the advice of patient advocates. Recurrent themes were developed until the saturation of data.

RESULTS

Thirty-two women took part in the study. Time, convenience, and lack of educational awareness were common barriers to healthy eating and physical activity plans. Enablers for change included meal planning and organization. Women regarded their diets pre-diagnosis as healthy, with small "tweaks" (such as portion control) required to comply with recommendations. Another significant facilitator to change was support from the woman's partner. This also set a benchmark for plans of diet maintenance within the family structure after pregnancy. Unlike dietary changes, a consistent theme was that exercise was considered a "chore" in managing GDM and was unlikely to be continued in the long term. Practical advice offered by participants for other women with GDM included organization, realistic approaches, and lack of self-blame.

CONCLUSION

Women reported that changes in diet would be more achievable in the long term than changes in exercise patterns. Partners and the clinical team were significant sources of support. Women's views are crucial to providing clinicians with a comprehensive and holistic understanding of disease management. Involving women in self-care decisions and empowering women to manage their own health are key contributors to long-term behavior change as well as service provision and policy implementation.

Listeria Meningitis, one of your five a day? A case report of Listeria Monocytogenes Meningitis in a fit and well 62-year-old woman

Listeria Monocytogenes is transmitted via ingestion of contaminated food products and can cause invasive disease in susceptible hosts. Risk factors include immunocompromise; pregnancy; being elderly; and new-born. Listeriosis is uncommon but can occur in immunocompetent individuals and has a high mortality rate. We report a case of a 62-year-old female with no obvious risk factors who presented with atypical meningism. The patient was subsequently diagnosed with listeria meningitis and made a good recovery. The patient was a gardener regularly handling soil and ingested vegetables from her allotment patch; this case is reported to highlight less common risk factors and atypical ways in which listeria may present to the acute medical take.

A Qualitative Evaluation of a Simulation Training Initiative for Registrars Working in Acute Medicine

INTRODUCTION

We evaluated a simulation-based training day for medical registrars to define the hidden curriculum of the training.

METHODS

We interviewed participants to explore their reflections about the day, what they had learned and how it had influenced their practice. Interviews were conducted iteratively and analysed in accordance with content thematic analysis.

RESULTS

We established four themes: sharing (collaborative learning), sensing (comparing one's practice against peers'), transforming (development or change in practice based on learning from the day), and endorsing (appreciating authenticity in the simulation and psychological safety in debriefing).

CONCLUSION

This evaluation furthered our understanding of the self-reported learning outcomes of our participants. We encourage other institutions to perform similar evaluations to build a collaborative understanding of simulationbased education for medical registrars.

Developing priorities for quality improvement in acute medicine using a modified Delphi method A consensus process hosted by the Society for Acute Medicine Quality Improvement Committee (SAM-QI)

INTRODUCTION

The SAM Quality Improvement Committee (SAM-QI), set up in 2016, has worked over the last year to determine the priority Acute Medicine QI topics. They have also discussed and put forward proposals to improve QI training for Acute Medicine professionals.

METHODS

A modified Delphi process was completed over four rounds to determine priority QI topics. Online meetings were also used to develop proposals for QI training.

RESULTS

Same Day Emergency Care (SDEC) was chosen as the priority topic for QI work within Acute Medicine.

CONCLUSION

The SAM-QI group settled on SDEC being the priority topic for Acute Medicine QI development. Throughout the Delphi process SAM-QI has also developed proposals for QI training that will help Acute Medicine professionals deliver coordinated meaningful improvements in care.

AeDES: a next-generation monitoring and forecasting system for environmental suitability of Aedes-borne disease transmission

Aedes-borne diseases, such as dengue and chikungunya, are responsible for more than 50 million infections worldwide every year, with an overall increase of 30-fold in the last 50 years, mainly due to city population growth, more frequent travels and ecological changes. In the United States of America, the vast majority of Aedes-borne infections are imported from endemic regions by travelers, who can become new sources of mosquito infection upon their return home if the exposed population is susceptible to the disease, and if suitable environmental conditions for the mosquitoes and the virus are present. Since the susceptibility of the human population can be determined via periodic monitoring campaigns, the environmental suitability for the presence of mosquitoes and viruses becomes one of the most important pieces of information for decision makers in the health sector. We present a next-generation monitoring and forecasting system for [Formula: see text]-borne diseases' environmental suitability (AeDES) of transmission in the conterminous United States and transboundary regions, using calibrated ento-epidemiological models, climate models and temperature observations. After analyzing the seasonal predictive skill of AeDES, we briefly consider the recent Zika epidemic, and the compound effects of the current Central American dengue outbreak happening during the SARS-CoV-2 pandemic, to illustrate how a combination of tailored deterministic and probabilistic forecasts can inform key prevention and control strategies .

Prediction of Atypical Ductal Hyperplasia Upgrades Through a Machine Learning Approach to Reduce Unnecessary Surgical Excisions

PURPOSE

Surgical excision is currently recommended for all occurrences of atypical ductal hyperplasia (ADH) found on core needle biopsies for malignancy diagnoses and treatment of lesions. The excision of all ADH lesions may lead to overtreatment, which results in invasive surgeries for benign lesions in many women. A machine learning method to predict ADH upgrade may help clinicians and patients decide whether combined active surveillance and hormonal therapy is a reasonable alternative to surgical excision.

METHODS

The following six machine learning models were developed to predict ADH upgrade from core needle biopsy: gradient-boosting trees, random forest, radial support vector machine (SVM), weighted K-nearest neighbors (KNN), logistic elastic net, and logistic regression. The study cohort consisted of 128 lesions from 124 women at a tertiary academic care center in New Hampshire who had ADH on core needle biopsy and who underwent an associated surgical excision from 2011 to 2017.

RESULTS

The best-performing models were gradient-boosting trees (area under the curve [AUC], 68%; accuracy, 78%) and random forest (AUC, 67%; accuracy, 77%). The top five most important features that determined ADH upgrade were age at biopsy, lesion size, number of biopsies, needle gauge, and personal and family history of breast cancer. Using the random forest model, 98% of all malignancies would have been diagnosed through surgical biopsies, whereas 16% of unnecessary surgeries on benign lesions could have been avoided (ie, 87% sensitivity at 45% specificity).

CONCLUSION

These results add to the growing body of support for machine learning models as useful aids for clinicians and patients in decisions about the clinical management of ADH.

Opioid analgesia and the somatosensory memory of neonatal surgical injury in the adult rat

Background

Nociceptive input during early development can produce somatosensory memory that influences future pain response. Hind-paw incision during the 1st postnatal week in the rat enhances re-incision hyperalgesia in adulthood. We now evaluate its modulation by neonatal analgesia.

Methods

Neonatal rats [Postnatal Day 3 (P3)] received saline, intrathecal morphine 0.1 mg kg−1 (IT), subcutaneous morphine 1 mg kg⁻¹ (SC), or sciatic levobupivacaine block (LA) before and after plantar hind-paw incision (three×2 hourly injections). Six weeks later, behavioural thresholds and electromyography (EMG) measures of re-incision hyperalgesia were compared with an age-matched adult-only incision (IN) group. Morphine effects on spontaneous (conditioned place preference) and evoked (EMG sensitivity) pain after adult incision were compared with prior neonatal incision and saline or morphine groups. The acute neonatal effects of incision and analgesia on behavioural hyperalgesia at P3 were also evaluated.

Results

Adult re-incision hyperalgesia was not prevented by neonatal peri-incision morphine (saline, IT, and SC groups > IN; P<0.05–0.01). Neonatal sciatic block, but not morphine, prevented the enhanced re-incision reflex sensitivity in adulthood (LA < saline and morphine groups, P<0.01; LA vs IN, not significant). Morphine efficacy in adulthood was altered after morphine alone in the neonatal period, but not when administered with neonatal incision. Morphine prevented the acute incision-induced hyperalgesia in neonatal rats, but only sciatic block had a preventive analgesic effect at 24 h.

Conclusions

Long-term effects after neonatal injury highlight the need for preventive strategies. Despite effective analgesia at the time of neonatal incision, morphine as a sole analgesic did not alter the somatosensory memory of early-life surgical injury.

In situ changes of tropical crustose coralline algae along carbon dioxide gradients

Crustose coralline algae (CCA) fulfill important ecosystem functions in coral reefs, including reef framework stabilization and induction of larval settlement. To investigate in situ the effects of high carbon dioxide on CCA communities, we deployed settlement tiles at three tropical volcanic CO₂ seeps in Papua New Guinea along gradients spanning from 8.1 to 7.4 pH. After 5 and 13 months deployment, there was a steep transition from CCA presence to absence around pH 7.8 (660 μatm pCO₂): 98% of tiles had CCA at pH > 7.8, whereas only 20% of tiles had CCA at pH ≤ 7.8. As pH declined from 8.0 to 7.8, the least and most sensitive CCA species lost 43% and 85% of cover, respectively. Communities on upward facing surfaces exposed to high light and high grazing pressure showed less steep losses than those on shaded surfaces with low grazing. Direct CO₂ effects on early life stages were the main mechanisms determining CCA cover, rather than competitive interactions with other benthic groups. Importantly, declines were steepest at near-ambient pH, suggesting that CCA may have already declined in abundance due to the recent seawater pH decline of 0.1 units, and that future severe losses are likely with increasing ocean acidification.

Cross-talk between toll-like receptor 4 (TLR4) and proteinase-activated receptor 2 (PAR(2) ) is involved in vascular function

BACKGROUND AND PURPOSE

Proteinase-activated receptors (PARs) and toll-like receptors (TLRs) are involved in innate immune responses. The aim of this study was to evaluate the possible cross-talk between PAR(2) and TLR4 in vessels in physiological condition and how it varies following stimulation of TLR4 by using in vivo and ex vivo models.

EXPERIMENTAL APPROACH

Thoracic aortas were harvested from both naïve and endotoxaemic rats for in vitro studies. Arterial blood pressure was monitored in anaesthetized rats in vivo. LPS was used as a TLR4 agonist while PAR(2) activating peptide (AP) was used as a PAR(2) agonist. Aortas harvested from TLR4(-/-) mice were also used to characterize the PAR(2) response.

KEY RESULTS

PAR(2) , but not TLR4, expression was enhanced in aortas of endotoxaemic rats. PAR(2) AP-induced vasorelaxation was increased in aortic rings of LPS-treated rats. TLR4 inhibitors, curcumine and resveratrol, reduced PAR(2) AP-induced vasorelaxation and PAR(2) AP-induced hypotension in both naïve and endotoxaemic rats. Finally, in aortic rings from TLR4(-/-) mice, the expression of PAR(2) was reduced and the PAR(2) AP-induced vasodilatation impaired compared with those from wild-type mice and both resveratrol and curcumine were ineffective.

CONCLUSIONS AND IMPLICATIONS

Cross-talk between PAR(2) and TLR4 contributes to vascular homeostasis.

Alveolar duct expansion greatly enhances aerosol deposition: a three-dimensional computational fluid dynamics study

Obtaining in vivo data of particle transport in the human lung is often difficult, if not impossible. Computational fluid dynamics (CFD) can provide detailed information on aerosol transport in realistic airway geometries. This paper provides a review of the key CFD studies of aerosol transport in the acinar region of the human lung. It also describes the first ever three-dimensional model of a single fully alveolated duct with moving boundaries allowing for the cyclic expansion and contraction that occurs during breathing. Studies of intra-acinar aerosol transport performed in models with stationary walls (SWs) showed that flow patterns were influenced by the geometric characteristics of the alveolar aperture, the presence of the alveolar septa contributed to the penetration of the particles into the lung periphery and there were large inhomogeneities in deposition patterns within the acinar structure. Recent studies have now used acinar models with moving walls. In these cases, particles penetrate the alveolar cavities not only as a result of sedimentation and diffusion but also as a result of convective transport, resulting in a much higher deposition prediction than that in SW models. Thus, models that fail to incorporate alveolar wall motions probably underestimate aerosol deposition in the acinar region of the lung.

Pharmacology of airways and vessels in lung slices in situ: role of endogenous dilator hormones

Small airway and vessels play a critical role in chronic airway and pulmonary vascular diseases, but their pharmacology has not been well characterised. We have studied airway and vascular responses in rat lung slices and separately in vitro using myography. In lung slices, under basal conditions, acetylcholine contracted airways, but had no vascular effect. The thromboxane mimetic, U46619 contracted both vessels and airways. In the presence of U46619, acetylcholine dilated vessels, but further contracted airways, an effect that was blocked by the nitric oxide synthase inhibitor L-NG-nitro-L-arginine or apamin plus charybdotoxin, which inhibit endothelial-derived hyperpolarising factor. Airway responses in lung slices were unaffected by L-NGnitro-L-arginine methyl ester, indomethacin or apamin plus charybdotoxin. By contrast, apamin plus charybdotoxin contracted bronchi studied in isolation. Our observations are the first to identify mechanisms of endothelium dependent dilations in precision cut lung slices and the potential for transverse hormonal communication between airways and vessels.

Dissociation of telomerase activity and telomere length maintenance in primitive human hematopoietic cells

Primitive human hematopoietic cells have low endogenous telomerase activity, yet telomeres are not maintained. In contrast, ectopic telomerase expression in fibroblasts and other cells leads to telomere length maintenance or elongation. It is unclear whether this disparity can be attributed to telomerase level or stems from fundamentally different telomere biology. Here, we show that telomerase overexpression does not prevent proliferation-associated telomere shortening in human hematopoietic cells, pointing to the existence of cell type-specific differences in telomere dynamics. Furthermore, we observed eventual stabilization of telomere length without detectable changes in telomerase activity during establishment of two leukemic cell lines from normal cord blood cells, indicating that additional cooperating events are required for telomere maintenance in immortalized human hematopoietic cells.

Direct evidence for cooperating genetic events in the leukemic transformation of normal human hematopoietic cells

Although genetic abnormalities associated with hematological malignancies are readily identified, the natural history of human leukemia cannot be observed because initiating and subsequent transforming events occur before clinical presentation. Furthermore, it has not been possible to study leukemogenesis in vitro as normal human cells do not spontaneously transform. Thus, the nature and sequence of genetic changes required to convert human hematopoietic cells into leukemia cells have never been directly examined. We have developed a system where the first step in the leukemogenic process is an engineered disruption of differentiation and self-renewal due to expression of the TLS-ERG oncogene, followed in some cases by overexpression of hTERT. In two of 13 experiments, transduced cells underwent step-wise transformation and immortalization through spontaneous acquisition of additional changes. The acquired karyotypic abnormalities and alterations including upregulation of Bmi-1 and telomerase all occur in acute myeloid leukemia (AML), establishing the relevance of this system. One resultant cell line studied in depth exhibits cellular properties characteristic of AML, notably a hierarchical organization initiated by leukemic stem cells that differentiate abnormally. These findings provide direct evidence for multiple cooperating events in human leukemogenesis, and provide a foundation for studying the genetic changes that occur during leukemic initiation and progression.

Functional multimerization of the human telomerase reverse transcriptase

The telomerase enzyme exists as a large complex (approximately 1,000 kDa) in mammals and at minimum is composed of the telomerase RNA and the catalytic subunit telomerase reverse transcriptase (TERT). In Saccharomyces cerevisiae, telomerase appears to function as an interdependent dimer or multimer in vivo (J. Prescott and E. H. Blackburn, Genes Dev. 11:2790-2800, 1997). However, the requirements for multimerization are not known, and it remained unclear whether telomerase exists as a multimer in other organisms. We show here that human TERT (hTERT) forms a functional multimer in a rabbit reticulocyte lysate reconstitution assay and in human cell extracts. Two separate, catalytically inactive TERT proteins can complement each other in trans to reconstitute catalytic activity. This complementation requires the amino terminus of one hTERT and the reverse transcriptase and C-terminal domains of the second hTERT. The telomerase RNA must associate with only the latter hTERT for reconstitution of telomerase activity to occur. Multimerization of telomerase also facilitates the recognition and elongation of substrates in vitro and in vivo. These data suggest that the catalytic core of human telomerase may exist as a functionally cooperative dimer or multimer in vivo.

The Telomerase/vault-associated protein TEP1 is required for vault RNA stability and its association with the vault particle

Vaults and telomerase are ribonucleoprotein (RNP) particles that share a common protein subunit, TEP1. Although its role in either complex has not yet been defined, TEP1 has been shown to interact with the mouse telomerase RNA and with several of the human vault RNAs in a yeast three-hybrid assay. An mTep1(-/-) mouse was previously generated which resulted in no apparent change in telomere length or telomerase activity in six generations of mTep1-deficient mice. Here we show that the levels of the telomerase RNA and its association with the telomerase RNP are also unaffected in mTep1(-/-) mice. Although vaults purified from the livers of mTep1(-/-) mice appear structurally intact by both negative stain and cryoelectron microscopy, three-dimensional reconstruction of the mTep1(-/-) vault revealed less density in the cap than previously observed for the intact rat vault. Furthermore, the absence of TEP1 completely disrupted the stable association of the vault RNA with the purified vault particle and also resulted in a decrease in the levels and stability of the vault RNA. Therefore, we have uncovered a novel role for TEP1 in vivo as an integral vault protein important for the stabilization and recruitment of the vault RNA to the vault particle.

The telomerase reverse transcriptase is limiting and necessary for telomerase function in vivo

Mammalian telomerase is essential for the maintenance of telomere length [1-5]. Its catalytic core comprises a reverse transcriptase component (TERT) and an RNA component. While the biochemical role of mammalian TERT is well established [6-11], it is unknown whether it is sufficient for telomere-length maintenance, chromosome stability or other cellular processes. Cells from mice in which the mTert gene had been disrupted showed progressive loss of telomere DNA, a phenotype similar to cells in which the gene encoding the telomerase RNA component (mTR) has been disrupted [1,12]. On prolonged growth, mTert-deficient embryonic stem (ES) cells exhibited genomic instability, aneuploidy and telomeric fusions. ES cells heterozygous for the mTert disruption also showed telomere attrition, a phenotype that differs from heterozygous mTR cells [12]. Thus, telomere maintenance in mammals is carried out by a single, limiting TERT.

Telomerase-associated protein TEP1 is not essential for telomerase activity or telomere length maintenance in vivo

TEP1 is a mammalian telomerase-associated protein with similarity to the Tetrahymena telomerase protein p80. Like p80, TEP1 is associated with telomerase activity and the telomerase reverse transcriptase, and it specifically interacts with the telomerase RNA. To determine the role of mTep1 in telomerase function in vivo, we generated mouse embryonic stem (ES) cells and mice lacking mTep1. The mTep1-deficient (mTep1(-/-)) mice were viable and were bred for seven successive generations with no obvious phenotypic abnormalities. All murine tissues from mTep1(-/-) mice possessed a level of telomerase activity comparable to that in wild-type mice. In addition, analysis of several tissues that normally lack telomerase activity revealed no reactivation of telomerase activity in mTep1(-/-) mice. Telomere length, even in later generations of mTep1(-/-) mice, was equivalent to that in wild-type animals. ES cells deficient in mTep1 also showed no detectable alteration in telomerase activity or telomere length with increased passage in culture. Thus, mTep1 appears to be completely dispensable for telomerase function in vivo. Recently, TEP1 has been identified within a second ribonucleoprotein (RNP) complex, the vault particle. TEP1 can also specifically bind to a small RNA, vRNA, which is associated with the vault particle and is unrelated in sequence to mammalian telomerase RNA. These results reveal that TEP1 is an RNA binding protein that is not restricted to the telomerase complex and that TEP1 plays a redundant role in the assembly or localization of the telomerase RNP in vivo.

Polymerization defects within human telomerase are distinct from telomerase RNA and TEP1 binding

The minimal, active core of human telomerase is postulated to contain two components, the telomerase RNA hTER and the telomerase reverse transcriptase hTERT. The reconstitution of human telomerase activity in vitro has facilitated the identification of sequences within the telomerase RNA and the RT motifs of hTERT that are essential for telomerase activity. However, the precise role of residues outside the RT domain of hTERT is unknown. Here we have delineated several regions within hTERT that are important for telomerase catalysis, primer use, and interaction with the telomerase RNA and the telomerase-associated protein TEP1. In particular, certain deletions of the amino and carboxy terminus of hTERT that retained an interaction with telomerase RNA and TEP1 were nonetheless completely inactive in vitro and in vivo. Furthermore, hTERT truncations lacking the amino terminus that were competent to bind the telomerase RNA were severely compromised for the ability to elongate telomeric and nontelomeric primers. These results suggest that the interaction of telomerase RNA with hTERT can be functionally uncoupled from polymerization, and that there are regions outside the RT domain of hTERT that are critical for telomerase activity and primer use. These results establish that the human telomerase RT possesses unique polymerization determinants that distinguish it from other RTs.

Antibody responses to Yersinia pestis F1-antigen expressed in Salmonella typhimurium aroA from in vivo-inducible promoters

Attenuated mutants of Salmonella typhimurium are being evaluated as delivery systems for a variety of heterologous vaccine antigens. Gene promoters which are induced in vivo can direct the stable expression of genes encoding these antigens. We have investigated the utility of the phoP, ompC, pagC and lacZ gene promoters for expression of the Y. pestis F1-antigen in S. typhimurium SL3261 (aroA). After i.g. (intragastric) dosing the highest level of spleen colonisation was found with recombinant Salmonella expressing F1-antigen from the phoP gene promoter, and this recombinant was most effective in inducing serum and mucosal antibody responses. The use of the pagC gene promoter to direct expression of F1-antigen resulted in the induction of serum and mucosal antibody responses even though the recombinant Salmonella were unable to colonise spleen tissues suggesting that colonisation of these tissues is not essential for the induction of antibody responses.

Telomeres, telomerase, and cancer: life on the edge of genomic stability

The presence of telomerase activity in most human tumors, but not in many normal somatic tissues, has raised considerable interest in telomerase as a possible anticancer therapy. Recent advances in the cloning and characterization of mammalian telomerase components have paved the way for a more detailed understanding of the role of telomerase and telomere length maintenance in cell proliferation. Here, we summarize the most recent biochemical and genetic evidence suggesting that telomere length maintenance by telomerase is critical to the proliferative ability of some immortalized mammalian cells in culture and in vivo.

Vaults and telomerase share a common subunit, TEP1

Vaults are large cytoplasmic ribonucleoprotein complexes of undetermined function. Mammalian vaults have two high molecular mass proteins of 193 and 240 kDa. We have identified a partial cDNA encoding the 240-kDa vault protein and determined it is identical to the mammalian telomerase-associated component, TEP1. TEP1 is the mammalian homolog of the Tetrahymena p80 telomerase protein and has been shown to interact specifically with mammalian telomerase RNA and the catalytic protein subunit hTERT. We show that while TEP1 is a component of the vault particle, vaults have no detectable telomerase activity. Using a yeast three-hybrid assay we demonstrate that several of the human vRNAs interact in a sequence-specific manner with TEP1. The presence of 16 WD40 repeats in the carboxyl terminus of the TEP1 protein is a convenient number for this protein to serve a structural or organizing role in the vault, a particle with eight-fold symmetry. The sharing of the TEP1 protein between vaults and telomerase suggests that TEP1 may play a common role in some aspect of ribonucleoprotein structure, function, or assembly.

Telomere shortening and apoptosis in telomerase-inhibited human tumor cells

Despite a strong correlation between telomerase activity and malignancy, the outcome of telomerase inhibition in human tumor cells has not been examined. Here, we have addressed the role of telomerase activity in the proliferation of human tumor and immortal cells by inhibiting TERT function. Inducible dominant-negative mutants of hTERT dramatically reduced the level of endogenous telomerase activity in tumor cell lines. Clones with short telomeres continued to divide, then exhibited an increase in abnormal mitoses followed by massive apoptosis leading to the loss of the entire population. This cell death was telomere-length dependent, as cells with long telomeres were viable but exhibited telomere shortening at a rate similar to that of mortal cells. It appears that telomerase inhibition in cells with short telomeres lead to chromosomal damage, which in turn trigger apoptotic cell death. These results provide the first direct evidence that telomerase is required for the maintenance of human tumor and immortal cell viability, and suggest that tumors with short telomeres may be effectively and rapidly killed following telomerase inhibition.

Ultrasonographic and clinical predictors of intussusception

OBJECTIVE

The objective of this study was to determine the positive and negative clinical predictors of intussusception and the correlation of ultrasonography and air enema in establishing this diagnosis.

STUDY DESIGN

This was a prospective descriptive cohort study.

SETTING

This study was performed in a tertiary care pediatric emergency department.

PARTICIPANTS

Eighty-eight of 245 candidates were assessed for clinical predictors of intussusception. All 245 cases were examined for correlation between ultrasonography and air enema.

INTERVENTIONS

A questionnaire, ultrasonography, and air enema were used.

RESULTS

Thirty-five of the 88 patients assessed for clinical predictors were positive for intussusception. Significant positive predictors were right upper quadrant abdominal mass (positive predictive value [PPV] 94%), gross blood in stool (PPV 80%), blood on rectal examination (PPV 78%), the triad of intermittent abdominal pain, vomiting, and right upper quadrant abdominal mass (PPV 93%, p = 0.0001), and the triad with occult or gross blood per rectum (PPV 100%, p = not significant). Significant negative predictors were a combination of > or = 3 of 10 clinically significant negative features (negative predictive value 77%, p = 0.035). Of the total 245 cases, intussusception (as confirmed by doughnut, target, or pseudokidney sign) was ruled out by ultrasonography in 97.4%. Alternate ultrasound findings comprised 27% of negative cases.

CONCLUSIONS

Excellent positive predictors of intussusception were identified prospectively. Although no reliable negative predictors were found, patients at low risk may be screened by ultrasonography.

Refined genetic mapping of the darier locus to a <1-cM region of chromosome 12q24.1, and construction of a complete, high-resolution P1 artificial chromosome/bacterial artificial chromosome contig of the critical region

Darier disease (DD) (MIM 124200) is an autosomal dominant skin disorder characterized by loss of adhesion between epidermal cells and by abnormal keratinization. We present linkage analysis showing, in four families, key recombination events that refine the location of the DD locus on chromosome 12q23-24.1 to a region of <1 cM. We have constructed a YAC/P1 artificial chromosome (PAC)/bacterial artificial chromosome (BAC)-based physical map that encompasses this refined DD region. The map consists of 35 YAC, 69 PAC, 16 BAC, and 2 cosmid clones that were ordered by mapping 54 anonymous sequence-tagged sites. The critical region is estimated to be 2.4 Mb in size, with an average marker resolution of 37.5 kb. The refinement of the critical interval excludes the ALDH2, RPL6, PTPN11, and OAS genes, as well as seven expressed sequence tags (ESTs) previously mapped in the DD region. The three known genes (ATP2A2, PPP1CC, and SCA2) and the 10 ESTs mapped within the critical region are not obvious candidates for the DD gene. Therefore, this detailed integrated physical, genetic, and partial transcript map provides an important resource for the isolation of the DD gene and, possibly, other disease genes.

Reconstitution of human telomerase activity in vitro

Telomerase is a ribonucleoprotein enzyme complex that adds single-stranded telomere DNA to chromosome ends [1]. The RNA component of telomerase contains the template for telomeric DNA addition and is essential for activity [1,2]. Telomerase proteins have been identified in ciliates, yeast and mammals [3-12]. In Saccharomyces cerevisiae, the Est2 protein is homologous to the 123 kDa reverse transcriptase subunit of Euplotes telomerase, and is essential for telomerase activity [8]. In humans, telomerase activity is associated with the telomerase RNA hTR [13], the telomerase RNA-binding protein TP1/TLP1 [5,12] and the TP2 protein encoded by the human EST2 homolog [12] (also known as TRT1, hEST2 or TCS1 [9-11]). The minimal complex sufficient for activity is, however, unknown. We have reconstituted human telomerase activity in reticulocyte lysates and find that only exogenous hTR and TP2 are required for telomerase activity in vitro. Recognition of telomerase RNA by TP2 was species specific, and nucleotides 10-159 of hTR were sufficient for telomerase activity. Telomerase activity immunoprecipitated from the reticulocyte lysate contained hTR and recombinant TP2. Substitution of conserved amino acid residues in the reverse transcriptase domain of TP2 completely abolished telomerase activity. We suggest that TP2 and hTR might represent the minimal catalytic core of human telomerase.

Human telomerase contains evolutionarily conserved catalytic and structural subunits

We have cloned and characterized a human gene encoding TP2 (telomerase-associated protein 2), a protein with similarity to reverse transcriptases and the catalytic telomerase subunits from Saccharomyces cerevisiae and Euplotes aediculatus. Indirect immunofluorescence revealed that TP2 was localized to the nucleus. Using antibodies to endogenous and epitope-tagged TP2, we found that TP2 was associated specifically with human telomerase activity and the recently identified telomerase-associated protein TP1. Mutation of conserved residues within the reverse transcriptase domain of TP2 severely reduced associated telomerase activity. These results suggest that telomerase is an evolutionarily conserved multisubunit complex composed of both structural and catalytic subunits.

Reciprocal inhibitory paracrine pathways link histamine and somatostatin secretion in the fundus of the stomach

The present study was designed to examine the functional linkage between histamine and somatostatin secretion in the fundus of the stomach. In segments of rat fundic mucosa, superfusion with thioperamide (H3 antagonist) increased somatostatin and decreased histamine secretion; superfusion with (R)(-)-alpha-methylhistamine (H3 agonist) had the opposite effect, decreasing somatostatin and increasing histamine secretion. The pattern implied that endogenous histamine, acting via H3 receptors, exerts an inhibitory paracrine influence on somatostatin secretion. Superfusion with somatostatin antibody (1:250) increased histamine secretion, implying that endogenous somatostatin, in turn, exerts an inhibitory paracrine influence on histamine secretion. Somatostatin antibody also abolished the decrease in histamine secretion induced by thioperamide and the increase in histamine secretion induced by (R)(-)-alpha-methylhistamine, implying that changes in histamine secretion induced by activation of H3 receptors reflect changes in somatostatin secretion. Superfusion with the muscarinic agonist methacholine alone and in the presence of either H3 agonist or H3 antagonist confirmed the existence of reciprocal inhibitory pathways linking somatostatin and histamine. We conclude that fundic histamine and somatostatin secretion are linked via reciprocal inhibitory paracrine pathways that serve to amplify the regulatory influence of somatostatin.

Complications of Fleet enema administration and suggested guidelines for use in the pediatric emergency department

INTRODUCTION

Hypertonic sodium phosphate enema solutions are commonly used for the treatment of acute constipation in the pediatric emergency department. The potential for severe metabolic derangement and death in children with gastrointestinal and/or renal abnormalities and these reported as normal has been documented in the literature.

OBJECTIVE

To develop guidelines for the safe and effective use of hypertonic sodium phosphate enema solutions such as Fleet enema, in the pediatric emergency department setting.

RESOURCES

A comprehensive review of the literature was conducted using the MEDLINE database for the time period 1966 to September 1995. Resources used within our institution, the Hospital for Sick Children, Toronto, Ontario, included Staff of the Emergency and General Surgery Departments.

SUMMARY

The guidelines provided will promote safe use of hypertonic sodium phosphate enema solutions for the treatment of acute constipation in children presenting to the emergency department.

A mammalian telomerase-associated protein

The telomerase ribonucleoprotein catalyzes the addition of new telomeres onto chromosome ends. A gene encoding a mammalian telomerase homolog called TP1 (telomerase-associated protein 1) was identified and cloned. TP1 exhibited extensive amino acid similarity to the Tetrahymena telomerase protein p80 and was shown to interact specifically with mammalian telomerase RNA. Antiserum to TP1 immunoprecipitated telomerase activity from cell extracts, suggesting that TP1 is associated with telomerase in vivo. The identification of TP1 suggests that telomerase-associated proteins are conserved from ciliates to humans.

Somatostatin receptor subtype 2 mediates inhibition of gastrin and histamine secretion from human, dog, and rat antrum

BACKGROUND & AIMS

In gastric antrum, somatostatin exerts a tonic inhibitory influence on gastrin and histamine secretion. Five different subtypes of somatostatin receptors, designated sst1-5, have been identified. sst2, sst3, and sst5 subtypes have been localized to the stomach by molecular biological techniques. The aim of this study was to identify the sst subtype regulating gastrin and histamine secretion in human, dog, and rat stomach.

METHODS

Mucosal segments from human, dog, and rat antrum were superfused with various concentrations of somatostatin 14 and somatostatin analogues selective for sst2, sst3, and sst5. Gastrin and histamine were measured by radioimmunoassay.

RESULTS

Somatostatin 14 and the sst2 agonist EC 5-20 inhibited gastrin and histamine secretion from all three species in a concentration-dependent manner, whereas the sst3 and sst5 agonists had no significant effect. Neutralization of endogenous somatostatin with the somatostatin antibody increased gastrin and histamine secretion. The increases were not affected by the gastrin antagonist but were abolished by the sst2 agonist, implying that the inhibitory influence of ambient somatostatin is exerted directly on the histamine cell rather than indirectly via changes in gastrin secretion.

CONCLUSIONS

Somatostatin inhibits gastrin and histamine secretion in human, dog, and rat antrum by activating sst2 receptors on gastrin and histamine cells.

Dual inhibitory pathways link antral somatostatin and histamine secretion in human, dog, and rat stomach

BACKGROUND & AIMS

The secretion and function of antral histamine are not known. The aims of this study were to characterize the mechanisms of histamine release from the gastric antrum of humans, dogs, and rats and to determine whether histamine can influence the secretion of somatostatin and gastrin.

METHODS

Somatostatin, gastrin, and histamine secretion from superfused antral segments was measured using radioimmunoassay.

RESULTS

Superfusion with thioperamide (H3 antagonist) increased somatostatin and decreased gastrin and histamine secretion in all three species; superfusion with (r)-alpha-methylhistamine (H3 agonist) had the opposite effect. The pattern implied that endogenous histamine, acting via H3 receptors, exerts an inhibitory paracrine influence on somatostatin secretion, which in turn regulates gastrin secretion. Superfusion with somatostatin antibody increased histamine secretion; the increase was not affected by the gastrin antagonist L-365,260, implying that it was not mediated by the concurrent increase in gastrin but by suppression of an inhibitory pathway linking somatostatin and histamine. Superfusion with methacholine alone and in the presence of either the H3 agonist or antagonist confirmed the existence of reciprocal inhibitory pathways linking somatostatin and histamine.

CONCLUSIONS

Antral histamine in humans, dogs, and rats is linked to antral somatostatin via reciprocal inhibitory paracrine pathways that serve to amplify the regulatory influence of somatostatin.

Complete nucleotide sequence of the herpesvirus simiae glycoprotein G gene and its expression as an immunogenic fusion protein in bacteria

The nucleotide sequence of a 2384 bp portion within the unique short (Us) region of the herpesvirus simiae (simian herpes B virus; SHBV) genome is presented. A partial and a complete open reading frame (ORF) were found within this nucleotide sequence. The partial ORF encodes the C terminus (147 amino acids) of a protein kinase which is highly conserved in the herpes simplex virus type 1 (HSV-1) and type 2 (HSV-2) and simian agent 8 (SA8) Us regions. The complete ORF is located 3' to the partial ORF within the 2384 bp sequence and encodes a 593 amino acid glycoprotein which appears to be closely related to the SA8 glycoprotein G (gG), but shares little amino acid similarity with gG of HSV-1 and -2. However, the complete ORF shares certain features conserved among most alphaherpesvirus gGs, notably three highly conserved cysteine residues and an adjacent N-glycosylation site. Therefore, it was concluded that this complete ORF encodes the SHBV gG. The 358 amino acid C-terminal portion of SHBV gG was expressed in Escherichia coli as a fusion protein and this was detected by immunoblotting with sera from cynomolgus monkeys which were either experimentally or naturally infected with SHBV. The purified fusion protein was inoculated into rabbits to raise an antiserum which recognized a number of apparently SHBV gG-specific protein bands in extracts from SHBV-infected simian cells.

Determination of radiation energy emitted by light activation units

Since the introduction in the 1970s of single paste composite materials, there has been a rapid increase in the range of both materials and activation light units. This investigation is being undertaken as part of a larger study where the characteristics of both composite materials, light activation units and composite material/light activation unit combinations, are being evaluated. This section of the study was undertaken to determine the characteristics of four light activation units. The equipment was developed to measure radiation energy over a wide range of illumination. This range can be from the relatively low intensity of radiation transmitted through restorative materials to the intensities of direct radiation from light activation units. The four light units tested had various radiation outputs between 225,000 lx and 75,000 lx. All the units, apart from one, showed a decrease in light output with successive applications. The units emitted radiation outside the optimum range of 440-500 nm, which may produce damaging radiation and glare. Although the extreme intensities varied threefold the effect on depth of cure of one-material varied by only 16%.

Gel shift and UV cross-linking analysis of Tetrahymena telomerase

Telomerase is an unusual ribonucleoprotein that synthesizes new telomeres onto chromosome ends. The enzyme has been most extensively characterized in ciliates, where the RNA component has been cloned from several species, and its elongation properties have been characterized in detail. To understand the substrate specificity and protein composition of telomerase, we have used gel shift and UV cross-linking to characterize the enzyme from the ciliate Tetrahymena thermophila. In a mobility shift assay, a complex was identified that contained telomerase RNA, co-purified with telomerase activity, and was sensitive to nuclease treatment. The mobility shift complexes specifically formed using several different single-stranded, telomeric sequences but not non-telomeric primers. These results suggest that the specificity of telomerase for G-rich primer sequences occurs at least in part at the level of primer binding. UV cross-linking analysis identified a 100-kDa cross-linked protein that may be a telomerase component.

Differences in the hypothalamic-pituitary-adrenal axis of black and white men

We previously found that, following intravenous administration of ovine corticotropin-releasing hormone (CRH), the plasma ACTH concentrations of Black women were approximately twice as high as those of White women; however, there were no corresponding differences in cortisol response. To determine whether this difference in ACTH secretion is also present in men, we studied the hypothalamic-pituitary-adrenal axis of 10 Black and 10 White weight-, age-, and education-matched men. Waist-to-hip ratio, 24-hour urine free cortisol excretion, and ACTH and cortisol responses to 1 microgram/kg ovine CRH were determined. There were no racial differences in waist-to-hip ratio, 24-hour urine free cortisol excretion, baseline free or total plasma cortisol and ACTH concentrations, or plasma cortisol response to CRH. However, CRH-stimulated plasma ACTH concentrations, measured in an extraction polyclonal radioimmunoassay, were significantly greater in Blacks than in Whites at all time points between 30 and 180 min after administration of CRH (area under curve (AUC) 1,796 +/- 245 pmol/l.min in Blacks vs. 1,278 +/- 121 pmol/l.min in Whites, p < 0.001). Neither cortisol nor ACTH AUCs were significantly correlated with Body Mass Index in Black or White men. We conclude that there are differences in the HPA axis of Black and White men similar to those found previously in women. The physiology underlying these differences remains to be understood.

Special programs for special groups

Special groups of persons with mental illness require individually tailored programs.

Procainamide-induced psychosis

The occurrence of procainamide-induced psychosis has not been mentioned previously in the nursing literature and is rarely reported in the medical literature. With the increasing use of procainamide in patients with both atrial and ventricular dysrhythmias, it is quite possible that nurses may encounter the phenomenon more frequently. It is also possible that it has been mistaken previously for ICU or psychologically-induced psychosis. Nurses routinely monitoring patients for physiologic effects of procainamide should also be alert for psychological effects as well. The onset of acute psychological sequelae such as procainamide-induced psychosis further complicates care of physiologically compromised patients. Rapid identification and intervention is important. It is especially important to listen to patient and family cues.

Procainamide-induced psychosis

The occurrence of procainamide-induced psychosis has not been mentioned previously in the nursing literature and is rarely reported in the medical literature. With the increasing use of procainamide in patients with both atrial and ventricular dysrhythmias, it is quite possible that nurses may encounter the phenomenon more frequently. It is also possible that it has been mistaken previously for ICU or psychologically-induced psychosis. Nurses routinely monitoring patients for physiologic effects of procainamide should also be alert for psychological effects as well. The onset of acute psychological sequelae such as procainamide-induced psychosis further complicates care of physiologically compromised patients. Rapid identification and intervention is important. It is especially important to listen to patient and family cues.