What skills do New Zealand clinicians have to provide first trimester abortion in primary care and are they willing?

OBJECTIVE

To determine the skills and intentions of health practitioners in New Zealand to provide first trimester abortion care.New Zealand achieved abortion law reform in 2020, changing how abortion could be delivered and experienced by pregnant people. However, little has changed in the way abortion care is provided.

STUDY DESIGN

This survey, which was deployed to a range of health practitioners via regulatory bodies and professional groups, used an online free text and tick box survey. Questions included demographics, scope of practice, abortion care experience, philosophical perspective on abortion, and skills transferable to abortion care. Data was analysed using descriptive statistics and deductive and inductive thematic analysis.

RESULTS

128 respondents included doctors, nurses, midwives, counsellors, and social workers from a range of practice settings, the majority from primary health (51%). Most respondents indicated competency or proficiency in clinical skills relevant to provision of early medical abortion. However, practitioners were more likely to indicate "I do not have this skill" or "support required" for: calculating gestational age by bimanual examination (42%), LARC (implant and IUC) insertion (36%), undertake a pregnancy related consultation using tikanga best practice guidelines (19%).Analysis of qualitative data showed three main themes; (1) support for abortion access and for abortion provision in primary care (2) levels of intention to provide abortion (3) critical components for an action plan for abortion in primary care.

CONCLUSION

Abortion care in the community has support from health practitioners. They identified needs including development of clinical skills, funding, and wider sector support.

O'Donnell-Luria-Rodan syndrome: description of a second multinational cohort and refinement of the phenotypic spectrum

BACKGROUND

O'Donnell-Luria-Rodan syndrome (ODLURO) is an autosomal-dominant neurodevelopmental disorder caused by pathogenic, mostly truncating variants in KMT2E. It was first described by O'Donnell-Luria et al in 2019 in a cohort of 38 patients. Clinical features encompass macrocephaly, mild intellectual disability (ID), autism spectrum disorder (ASD) susceptibility and seizure susceptibility.

METHODS

Affected individuals were ascertained at paediatric and genetic centres in various countries by diagnostic chromosome microarray or exome/genome sequencing. Patients were collected into a case cohort and were systematically phenotyped where possible.

RESULTS

We report 18 additional patients from 17 families with genetically confirmed ODLURO. We identified 15 different heterozygous likely pathogenic or pathogenic sequence variants (14 novel) and two partial microdeletions of KMT2E. We confirm and refine the phenotypic spectrum of the KMT2E-related neurodevelopmental disorder, especially concerning cognitive development, with rather mild ID and macrocephaly with subtle facial features in most patients. We observe a high prevalence of ASD in our cohort (41%), while seizures are present in only two patients. We extend the phenotypic spectrum by sleep disturbances.

CONCLUSION

Our study, bringing the total of known patients with ODLURO to more than 60 within 2 years of the first publication, suggests an unexpectedly high relative frequency of this syndrome worldwide. It seems likely that ODLURO, although just recently described, is among the more common single-gene aetiologies of neurodevelopmental delay and ASD. We present the second systematic case series of patients with ODLURO, further refining the mutational and phenotypic spectrum of this not-so-rare syndrome.

Infant mortality: the contribution of genetic disorders

OBJECTIVE

To determine the proportion of infant deaths occurring in the setting of a confirmed genetic disorder.

STUDY DESIGN

A retrospective analysis of the electronic medical records of infants born from 1 January, 2011 to 1 June, 2017, who died prior to 1 year of age.

RESULTS

Five hundred and seventy three deceased infants were identified. One hundred and seventeen were confirmed to have a molecular or cytogenetic diagnosis in a clinical diagnostic laboratory and an additional seven were diagnosed by research testing for a total of 124/573 (22%) diagnosed infants. A total of 67/124 (54%) had chromosomal disorders and 58/124 (47%) had single gene disorders (one infant had both). The proportion of diagnoses made by sequencing technologies, such as exome sequencing, increased over the years.

CONCLUSIONS

The prevalence of confirmed genetic disorders within our cohort of infant deaths is higher than that previously reported. Increased efforts are needed to further understand the mortality burden of genetic disorders in infancy.

Intravenous lidocaine infusion as a component of multimodal analgesia for colorectal surgery-measurement of plasma levels

Background

Growing evidence suggests that intravenous lidocaine as a component of multimodal analgesia improves recovery after major colorectal surgery. There is little published data regarding ideal dosing and target plasma concentration in this context, and we wanted to establish our dosing schedule was safe by measuring blood levels of lidocaine.

Methods

We measured the plasma lidocaine concentration of 32 patients at 30 min, 6 h and 12 h after starting intravenous lidocaine infusion for analgesia after major colorectal surgery. Patients received a bolus of 1.5 mg kg⁻¹ over 20 min at the time of induction of anaesthesia. This was followed by a continuous infusion of 2% w/v lidocaine at 3 ml hr⁻¹ (60 mg hr⁻¹) for patients weighing up to 70 kg and 6 ml hr⁻¹ (120 mg hr⁻¹) for patients weighing over 70 kg, using actual body weight.

Results

The overall mean plasma lidocaine concentration was 4.0 μg ml⁻¹ (range 0.6–12.3 μg ml⁻¹). In patients treated with the higher infusion dose, the mean concentration was 4.6 μg ml⁻¹ compared to 3.2 μg ml⁻¹ in those patients on the lower dose. Mean levels were higher at 6 h than 30 min and higher again at 12 h. There were no adverse events or reports of symptoms of local anaesthetic toxicity.

Conclusions

Whilst there were no signs or symptoms of lidocaine toxicity in our patients, there was a wide range of plasma concentrations including some over 10 μg ml⁻¹; a level above which symptoms of toxicity may be expected. We have changed our dosing protocol to using ideal rather than actual body weight based on these results.

Adverse obstetric history is not a risk factor for poor outcome after ventral rectopexy for obstructive defaecation syndrome

AIM

Ventral rectopexy (VR) has gained popularity in the management of obstructive defaecation syndrome (ODS) due to a symptomatic rectocele ± intussusception. Data on the efficacy and safety of VR are variable and there are few predictors of successful outcome. This study aimed to examine whether or not an adverse obstetric history influenced the functional outcome following VR for ODS.

METHOD

This was a retrospective study of a cohort of 76 consecutive patients who had undergone VR for ODS at a tertiary referral centre between 2012 and 2015. Patients were followed up by telephone questionnaire. The obstetric history and pre- and postoperative symptoms of ODS and faecal incontinence (FI) were obtained from telephone interviews.

RESULTS

In this cohort, symptoms of ODS were significantly improved by surgery, with 56% of patients showing a reduction of symptoms of 50% or more (P < 0.001). Subgroup analysis demonstrated that a lower body mass index (BMI; 24.4 vs 27.3 kg/m² ; P < 0.05) and shorter duration of symptoms (7 vs 10 years; P < 0.05) led to a better outcome. VR had no effect on FI. Obstetric factors such as foetal weight, instrumental delivery, episiotomy, perineal tear and total number of deliveries did not influence outcomes.

CONCLUSION

Patients with a less straightforward obstetric history can be reassured that this should not adversely influence the functional outcome after VR for ODS. Colorectal surgeons who offer this surgery should warn patients with an elevated BMI or with longstanding symptoms that the operation may be less successful than for those with a lower BMI or shorter duration of symptoms.

The people living with HIV stigma survey UK 2015: HIV-related sexual rejection and other experiences of stigma and discrimination among gay and heterosexual men

We aim to understand the difference in stigma and discrimination, in particular sexual rejection, experienced between gay and heterosexual men living with HIV in the UK. The People Living with HIV StigmaSurvey UK 2015 recruited a convenience sample of persons with HIV through over 120 cross sector community organisations and 46 HIV clinics to complete an online survey. 1162 men completed the survey, 969 (83%) gay men and 193 (17%) heterosexual men, 92% were on antiretroviral therapy. Compared to heterosexual men, gay men were significantly more likely to report worrying about workplace treatment in relation to their HIV (21% vs. 11%), worrying about HIV-related sexual rejection (42% vs 21%), avoiding sex because of their HIV status (37% vs. 23%), and experiencing HIV-related sexual rejection (27% vs. 9%) in the past 12 months. In a multivariate logistic regression controlling for other sociodemographic factors, being gay was a predictor of reporting HIV-related sexual rejection in the past 12 months (aOR 2.17, CI 1.16, 4.02). Both gay and heterosexual men living with HIV experienced stigma and discrimination in the past 12 months, and this was higher for gay men in terms of HIV-related sexual rejection. Due to the high proportion of men reporting sexual rejection, greater awareness and education of the low risk of transmission of HIV among people on effective treatment is needed to reduce stigma and sexual prejudice towards people living with HIV.

Intuitive eating is associated with glycaemic control in adolescents with type I diabetes mellitus

BACKGROUND

While there have been considerable advances in the medical management of type 1 diabetes mellitus (T1DM), for many, glycaemic control remains substandard. Nutrition and eating behaviour are important additional factors to consider with regards to T1DM management and outcomes. Intuitive eating is one such factor, and has not previously been investigated in T1DM. With this in mind, we undertook a study examining the relationship between intuitive eating and glycaemic control in adolescents with T1DM.

METHODS

A case-control study of adolescents with established T1DM, and age/sex matched controls was conducted. Demographic information, the Intuitive Eating Scale (IES), and HbA1c were collected. Statistical analysis was undertaken to explore associations between the IES and HbA1c as a marker of glycaemic control.

RESULTS

Data on 38 adolescents with T1DM, and 39 age/sex matched controls were obtained. Those with T1DM had significantly lower (by 0.5 SD) IES scores compared to controls (p = 0.009). Higher values of both total IES and the Eating for physical rather than emotional reasons subscale were associated with lower HbA1c: HbA1c 22% lower/whole unit increase in total IES mean score, HbA1c 11% lower/whole unit increase in Eating for physical rather than emotional reasons mean score, p = 0.017 and p = 0.009 respectively.

CONCLUSION

In adolescents with T1DM, there appears to be a strong association between intuitive eating, in particular the effect of emotion on eating, and glycaemic control. In addition, those with T1DM have lower scores for their intuitive eating behaviour compared to controls. Emotional eating could be a future target for screening and potentially intervening in those with T1DM, as part of a wider treatment package to improve glycaemic control. Continuing efforts are needed to fully understand the important dynamics of diabetes, adolescence, diet, emotion, and how these factors affect long term outcomes in those with T1DM.

Hydroxychloroquine-induced agranulocytosis in a patient with long-term rheumatoid arthritis

Agranulocytosis is a rare and little-known side effect of hydroxychloroquine use. This report describes the case of a 71-year-old woman with poorly controlled rheumatoid arthritis who developed agranulocytosis after several months of hydroxychloroquine therapy. She had been on several different disease-modifying antirheumatic drugs, including methotrexate and leflunomide, for her rheumatoid arthritis. Treatment became complicated following a diagnosis of leflunomide-induced pulmonary fibrosis that was discovered after an intensive care unit (ICU) admission for severe Pseudomonas pneumonia. All treatment was stopped apart from steroids and hydroxychloroquine. Because of persistent disabling symptoms, rituximab infusions were given, which improved the disease control. A second admission occurred after a routine blood test revealed agranulocytosis. Hydroxychloroquine was stopped, and after 24 h, she was discharged home. Blood counts returned to normal within 2 weeks of hydroxychloroquine cessation; hence, after the review of investigations, a diagnosis of hydroxychloroquine-induced agranulocytosis was made. This report considers current literature on hydroxychloroquine-induced agranulocytosis and explores the potential causes for this occurrence.

Low prevalence of significant carotid artery disease on ultrasound in patients proceeding to coronary artery bypass surgery

BACKGROUND

Cardiothoracic surgery is associated with an increased risk of perioperative stroke. Preoperative carotid ultrasonography can identify significant stenosis, but there is debate about the value of screening. The aims of this study were to (i) determine the prevalence of significant carotid artery disease in screened patients undergoing cardiothoracic surgery and (ii) correlate their ultrasonographic findings with perioperative strokes.

METHODS

Retrospective analysis of 166 patients (118 men, 48 women) who underwent a preoperative carotid ultrasound and coronary artery bypass graft surgery (CABG) from 2004 to 2007. Perioperative strokes were recorded and compared with ultrasonographic and clinical data. A separate cohort of 1423 patients (1064 men, 359 women) who underwent CABG over the same period was also evaluated.

RESULTS

Only 11 screened patients (6.6%) had significant (>70%) carotid artery disease and two of these underwent simultaneous carotid endarterectomy. There were five perioperative strokes in screened patients, four of which occurred in individuals with <50% disease. Compared with the non-screened cohort, ultrasound screened patients were older and more likely to have a prior stroke or transient ischaemic attack, hypertension, hypercholesterolaemia, peripheral vascular disease and/or renal impairment than non-screened patients. There was no significant difference in perioperative strokes compared with non-screened patients (3% vs 1.2% respectively, P= NS).

CONCLUSION

There is a low prevalence of significant carotid artery disease in ultrasound screened patients. The risk of perioperative strokes in screened patients is low and not significantly different from non-screened patients.

Occupational health advice in NICE guidelines

BACKGROUND

Sickness absence is a major concern for society costing > pound 13 billion annually. Seeking medical advice is highly recommended in managing sickness absence. The National Institute for Health and Clinical Excellence (NICE) provides guidance on treating ill-health and promoting public health. NICE has published >500 guidelines. There are three versions of each guideline including full (comprehensive version), NICE (summary of recommendations) and public version.

AIMS

To evaluate the availability of occupational health advice within relevant NICE guidelines.

METHODS

Guidelines were selected on the basis of the impact of the disease and its treatment on work ability. All selected guidelines were reviewed for occupational health advice. The findings were categorized in five main domains: impact of the disease on work, impact of work on the disease, rehabilitation, fitness to work and modifications.

RESULTS

Thirty-one published guidelines met the inclusion criteria. Advice on rehabilitation is most frequently referred to with 12 (39%) full, 8 (26%) NICE and 4 (13%) public information guidelines offering advice on this domain. Advice on return to work is the least frequent. The public versions of guidelines rarely offer advice on the studied domains. Occupational health organizations are enlisted as stakeholders in one guideline only. Two occupational health professionals have contributed to the development of two guidelines.

CONCLUSIONS

This study suggests that occupational health professionals and organizations should participate more actively in developing NICE guidelines to integrate work-related issues and occupational health advice into NICE guidelines.

Flat revertants of EJ human bladder carcinoma cells show two different mechanisms of reversion

To investigate the way in which ras proteins cause transformation, we have isolated revertants from human tumour cell lines which contain transforming ras genes. Two types of revertant have been isolated from the human fibrosarcoma cell line, HT1080. One class has normal and mutant alleles in a ratio of 2:1, compared to 1:1 in the parental cells, showing that reversion can be a dosage phenomenon. The other class has lost the transforming allele. All the HT1080 revertants isolated can be re-transformed by transforming ras proteins. To test whether reversion is due to a change in the relative amounts of normal and mutant proteins, or to a reduction in the absolute amount of the transforming protein, mixtures of the purified proteins were microinjected into 208F (Rat-1) cells, chosen because they are less sensitive to transformation by p21ras. Normal H-ras p21 was unable to suppress the transforming effects of the mutant ras protein when co-injected at up to ninefold excess. Revertants of EJ human bladder carcinoma cells were of two types: one was sensitive to re-transformation by oncogenically activated ras proteins, the other was not. The EJ revertants that are resistant to re-transformation fall into two classes, since hybrids of one revertant with the parental EJ cells are non-transformed, whereas hybrids of another revertant with the parental cells are transformed.

Impact of an interdisciplinary low vision service on the quality of life of low vision patients

AIM

To investigate the impact of an interdisciplinary low vision service on the vision related quality of life of service users.

METHODS

71 patients were interviewed 2 weeks before their appointment with the service and again 6 months later to assess any changes in their vision related quality of life. The majority of these patients had age related macular degeneration.

RESULTS

After contact with the service the majority of patients indicated a reduction in concern about most quality of life issues. They were significantly less anxious about deterioration of their vision, safety within the home, and coping with everyday life.

CONCLUSION

Improvements in many areas of their vision related quality of life indicate that this interdisciplinary low vision service has a positive impact on the lives of service users. However many patients were still unable to carry out their preferred everyday activities, and feelings of loneliness and isolation were unchanged. The identification of issues unrelieved by input from the service will be important in planning future service delivery.

Characterization of RFLP probe sequences for gene discovery and SSR development in Sorghum bicolor (L.) Moench

In this study, we collected and analyzed DNA sequence data for 789 previously mapped RFLP probes from Sorghum bicolor (L.) Moench. DNA sequences, comprising 894 non-redundant contigs and end sequences, were searched against three GenBank databases, nucleotide (nt), protein (nr) and EST (dbEST), using BLAST algorithms. Matching ESTs were also searched against nt and nr. Translated DNA sequences were then searched against the conserved domain database (CDD) to determine if functional domains/motifs were congruent with the proteins identified in previous searches. More than half (500/894 or 56%) of the query sequences had significant matches in at least one of the GenBank searches. Overall, proteins identified for 148 sequences (17%) were consistent among all searches, of which 66 sequences (7%) contained congruent coding domains. The RFLP probe sequences were also evaluated for the presence of simple sequence repeats (SSRs) and 60 SSRs were developed and assayed in an array of sorghum germplasm comprising inbreds, landraces and wild relatives. Overall, these SSR loci had lower levels of polymorphism ( D = 0.46, averaged over 51 polymorphic loci) compared with sorghum SSRs that were isolated by library hybridization screens ( D = 0.69, averaged over 38 polymorphic loci). This result was probably due to the relatively small proportion of di-nucleotide repeat-containing markers (42% of the total SSR loci) obtained from the DNA sequence data. These di-nucleotide markers also contained shorter repeat motifs than those isolated from genomic libraries. Based on BLAST results, 24 SSRs (40%) were located within, or near, previously annotated or hypothetical genes. We determined the location of 19 of these SSRs relative to putative coding regions. In general, SSRs located in coding regions were less polymorphic ( D = 0.07, averaged over three loci) than those from gene flanking regions, UTRs and introns ( D = 0.49, averaged over 16 loci). The sequence information and SSR loci generated through this study will be valuable for application to sorghum genetics and improvement, including gene discovery, marker-assisted selection, diversity and pedigree analyses, comparative mapping and evolutionary genetic studies.

Molecular dissection of complex traits in autopolyploids: mapping QTLs affecting sugar yield and related traits in sugarcane

Mapping quantitative trait loci (QTLs) for sugar yield and related traits will provide essential information for sugarcane improvement through marker-assisted selection. Two sugarcane segregating populations derived from interspecific crosses between Saccharum offinarum and Saccharum spontaneum with 264 and 239 individuals, respectively, were evaluated in three replications each for field performance from 1994 to 1996 at Weslaco, Texas. These two populations were analyzed for a total of 735 DNA marker loci to seek QTLs for sugar yield, pol, stalk weight, stalk number, fiber content and ash content. Among the 102 significant associations found between these six traits and DNA markers, 61 could be located on sugarcane linkage maps, while the other 41 were associated with unlinked DNA markers. Fifty of the 61 mapped QTLs were clustered in 12 genomic regions of seven sugarcane homologous groups. Many cases in which QTLs from different genotypes mapped to corresponding locations suggested that at least some of the QTLs on the same cluster might be different allelic forms of the same genes. With a few exceptions that explained part of the transgressive segregation observed for particular traits, the allele effects of most QTLs were consistent with the parental phenotype from which the allele was derived. Plants with a high sugar yield possessed a large number of positive QTLs for sugar yield components and a minimal number of negative QTLs. This indicates the potential effectiveness of marker-assisted selection for sugar yield in sugarcane.

Mapping QTLs for field resistance to the rice blast pathogen and evaluating their individual and combined utility in improved varieties

Lines from a Lemont x Teqing recombinant inbred population were evaluated for dilatory resistance to rice blast disease using: (1) the Standard Evaluation System (SES) for rating leaf blast, (2) the percentage diseased leaf area (%DLA), and (3) the area under a disease progress curve (AUDPC). RFLP mapping using 175 well-distributed loci revealed nine QTLs, one each on chromosomes 1, 2, 3, 4, 6, 7 and 9, with two loci on chromosome 12. All nine putative QTLs were associated with AUDPC, six with both a %DLA and a SES rating. Teqing contributed the resistance allele for all these loci except for the one located on chromosome 4. Individual QTLs accounted for 5-32% of the observed phenotypic variation, and combined QTL models accounted for 43-53%. Three QTLs were located near three of the four major resistance genes previously identified in this population. The resistances of both Lemont and Teqing were attributable to a combination of both major genes capable of inducing hypersensitive reactions and minor genes causing less-distinctive phenotypic differences. Interactions were noted between QTLs and major genes. Our findings are in support of the strategy of pyramiding major genes and QTLs in carefully selected combinations to develop improved varieties with resistance to the blast fungus that is both broad in spectrum and durable.

Appropriate subcellular localisation of prodrug-activating enzymes has important consequences for suicide gene therapy

Escherichia coli B nitroreductase (NR) has been expressed stably in MDA-MB-361 human breast adenocarcinoma cells either as the wild-type protein (wtNR), which is distributed evenly between the cytoplasmic and nuclear compartments, or targeted to the mitochondrion (mtNR). Whereas bacterial NR is active as a dimer, a proportion of wtNR is monomeric. In contrast, mtNR is mostly dimeric, suggesting that it adopts a more stable, native conformation. Despite this, when tested in gene-directed enzyme prodrug therapy cell cytotoxicity studies, cells expressing wtNR or mtNR had similar sensitivity to the prodrug CB1954 and mounted similar bystander killing effects. Furthermore, when short prodrug exposures were given, wtNR was more efficient at killing cells than mtNR. These data demonstrate that the site of enzyme expression and prodrug activation is an important variable that requires consideration in suicide gene therapy approaches.

Differentiation of separated mouse mammary luminal epithelial and myoepithelial cells cultured on EHS matrix analyzed by indirect immunofluorescence of cytoskeletal antigens

We have previously demonstrated that purified virgin mouse mammary luminal epithelial and myoepithelial cells promiscuously express cell type-specific cytokeratins when they are cloned in vitro. Changes in cytokeratin expression may be indicators of the loss or change of the differentiated identity of a cell. To investigate the factors that may be responsible for the maintenance of differentiated cellular identity, specifically cell-cell and cell-matrix interactions, we cloned flow-sorted mouse mammary epithelial cells on the extracellular matrix (ECM) derived from the Engelbreth-Holm-Swarm murine sarcoma (EHS matrix). Changes in cell differentiation on EHS, compared with culture on glass, were analyzed by comparing patterns of cytokeratin expression. The results indicate that ECM is responsible for maintenance of the differentiated identity of basal/myoepithelial cells and prevents the inappropriate expression of luminal antigens seen on glass or plastic. Luminal cell identity in the form of retention of luminal markers and absence of basal/myoepithelial antigens, on the contrary, appears to depend on homotypic cell-cell contacts and interactions. The results also show that luminal cells (or a subpopulation of them) can generate a cell layer that expresses only basal cytokeratin markers (and no luminal cytokeratin markers) and may form a pluripotent compartment. (J Histochem Cytochem 47:1513-1524, 1999)

Absence of Brca2 causes genome instability by chromosome breakage and loss associated with centrosome amplification

Women heterozygous for mutations in the breast-cancer susceptibility genes BRCA1 and BRCA2 have a highly elevated risk of developing breast cancer [1]. BRCA1 and BRCA2 encode large proteins with no sequence similarity to one another. Although involvement in DNA repair and transcription has been suggested, it is still not understood how loss of function of these genes leads to breast cancer [2]. Embryonic fibroblasts (MEFs) derived from mice homozygous for a hypomorphic mutation (Brca2(Tr2014)) within the 3' region of exon 11 in Brca2 [3], or a similar mutation (Brca2(Tr)) [4], proliferate poorly in culture and overexpress the tumour suppressor p53 and the cyclin-dependent kinase inhibitor p21(Waf1/Cip1). These MEFs have intact p53-dependent DNA damage G(1)-S [3] [4] and G(2)-M checkpoints [4], but are impaired in DNA double-strand break repair [3] and develop chromosome aberrations [4]. Here, we report that Brca2(Tr2014/Tr2014) MEFs frequently develop micronuclei. These abnormal DNA-containing bodies were formed through both loss of acentric chromosome fragments and by chromosome missegregation, which resulted in aneuploidy. Absence of Brca2 also led to centrosome amplification, which we found associated with the formation of micronuclei. These data suggest a potential mechanism whereby loss of BRCA2 may, within subclones, drive the loss of cell-cycle regulation genes, enabling proliferation and tumourigenesis.

Interaction of axin and Dvl-2 proteins regulates Dvl-2-stimulated TCF-dependent transcription

Axin promotes the phosphorylation of beta-catenin by GSK-3beta, leading to beta-catenin degradation. Wnt signals interfere with beta-catenin turnover, resulting in enhanced transcription of target genes through the increased formation of beta-catenin complexes containing TCF transcription factors. Little is known about how GSK-3beta-mediated beta-catenin turnover is regulated in response to Wnt signals. We have explored the relationship between Axin and Dvl-2, a member of the Dishevelled family of proteins that function upstream of GSK-3beta. Expression of Dvl-2 activated TCF-dependent transcription. This was blocked by co-expression of GSK-3beta or Axin. Expression of a 59 amino acid GSK-3beta-binding region from Axin strongly activated transcription in the absence of an upstream signal. Introduction of a point mutation into full-length Axin that prevented GSK-3beta binding also generated a transcriptional activator. When co-expressed, Axin and Dvl-2 co-localized within expressing cells. When Dvl-2 localization was altered using a C-terminal CAAX motif, Axin was also redistributed, suggesting a close association between the two proteins, a conclusion supported by co-immunoprecipitation data. Deletion analysis suggested that Dvl-association determinants within Axin were contained between residues 603 and 810. The association of Axin with Dvl-2 may be important in the transmission of Wnt signals from Dvl-2 to GSK-3beta.

Cardiac valvular papillary fibroelastoma: a report of 2 cases

Papillary fibroelastomas are rare cardiac valve tumors with potential for life-threatening complications such as stroke or sudden death. We report 2 cases of papillary fibroelastoma that were found by echocardiography. The 1st tumor arose from the mitral valve in a patient who presented after multiple transient neurologic events. The 2nd tumor arose from the aortic valve and was found incidentally during coronary artery bypass grafting. Both patients underwent successful surgical removal of the tumor.

Requirement of Ras-GTP-Raf complexes for activation of Raf-1 by protein kinase C

Receptor tyrosine kinase-mediated activation of the Raf-1 protein kinase is coupled to the small guanosine triphosphate (GTP)-binding protein Ras. By contrast, protein kinase C (PKC)-mediated activation of Raf-1 is thought to be Ras independent. Nevertheless, stimulation of PKC in COS cells led to activation of Ras and formation of Ras-Raf-1 complexes containing active Raf-1. Raf-1 mutations that prevent its association with Ras blocked activation of Raf-1 by PKC. However, the activation of Raf-1 by PKC was not blocked by dominant negative Ras, indicating that PKC activates Ras by a mechanism distinct from that initiated by activation of receptor tyrosine kinases.

Ras signalling is required for inactivation of the tumour suppressor pRb cell-cycle control protein

Ras proteins act as molecular switches, responding to signals by entering the active GTP-bound, rather than the inactive GDP-bound, state. The inhibition of normal Ras proteins by microinjection of neutralizing antibody or expression of dominant-negative mutants has shown that Ras signalling is required for growth factors to stimulate DNA synthesis [1] [2], but the link between Ras and the cell-cycle machinery is not clear. Regulation of the phosphorylation state of the retinoblastoma protein (pRb), the product of the tumour suppressor gene Rb, is a key event in the progression of cells from G1 phase into S phase. In growth-arrested or early G1 cells, pRb is hypophosphorylated and binds to transcription factors of the E2F family [3]. These pRb-E2F complexes act to suppress gene transcription required for entry into DNA synthesis either by preventing E2F from stimulating transcription or by actively repressing transcription [4]. During G1, cyclin-dependent kinases (CDKs) become activated and phosphorylate pRb at multiple sites, leading to the dissolution of pRb-E2F complexes and gene transcription [5]. Here, we have tested the hypothesis that Ras signalling is required for the inactivation of pRb. A neutralizing antibody directed against p21Ras was microinjected into cells derived from mutant mouse embryos that lack Rb or CDK inhibitors (CDKIs). Cells without pRb or the p16 CDKI were more resistant to the inhibitory effects of the anti-Ras antibody. DNA synthesis in some tumour cell lines was completely resistant to the anti-Ras injection, indicating that p21Ras is required for pRb inactivation but also has other functions in cell-cycle progression.

A member of the MAP kinase phosphatase gene family in mouse containing a complex trinucleotide repeat in the coding region

We have identified a novel mouse gene encoding a protein that shows high homology to the dual-specificity tyrosine/threonine phosphatase family of proteins. The gene encodes a 5 kb transcript which is expressed predominantly in brain and lung and contains a translated complex trinucleotide repeat within the coding region. Using interspecific mouse backcross analysis, the gene has been localised to distal mouse chromosome 7. In human, homologous sequences are located in the syntenic region on distal chromosome 11p as well as to chromosome 10q11.2 and 10q22. The presence of a CG-rich trinucleotide repeat in the coding region provides a target for mutation which might result in loss of function or altered properties of this phosphatase.

EGF triggers neuronal differentiation of PC12 cells that overexpress the EGF receptor

BACKGROUND

Mitogen-activated protein (MAP) kinase is the central component of a signal transduction pathway that is activated by growth factors interacting with receptors that have protein tyrosine kinase activity. The stimulation of PC12 phaeochromocytoma cells with nerve growth factor leads to the sustained activation and nuclear translocation of the p42 and p44 isoforms of MAP kinase and induces the differentiation of these chromaffin cells to a sympathetic-neuron-like phenotype. In contrast, stimulation with epidermal growth factor induces a transient activation of p42 and p44 MAP kinases without pronounced nuclear translocation and does not trigger cell differentiation. We have examined whether the differential activation of MAP kinases forms the basis of the differential response of the cells to the two factors.

RESULTS

By overexpressing either wild-type or mutant receptors for epidermal growth factor in PC12 cells, we found that p42 and p44 MAP kinase activity remains elevated for longer in cells that overexpress receptors than in untransfected cells. Epidermal growth factor promotes both a striking nuclear translocation of p42 MAP kinase and the differentiation of the overexpressing cells.

CONCLUSIONS

Our results strongly suggest that the distinct effects of nerve growth factor and epidermal growth factor on PC12 cell differentiation can be explained by differences in the extent and duration of activation of p42 and p44 MAP kinases in response to the two factors, without invoking a signal transduction pathway specific to nerve growth factor.

N-terminally myristoylated Ras proteins require palmitoylation or a polybasic domain for plasma membrane localization

Plasma membrane targeting of Ras requires CAAX motif modifications together with a second signal from an adjacent polybasic domain or nearby cysteine palmitoylation sites. N-terminal myristoylation is known to restore membrane binding to H-ras C186S (C-186 is changed to S), a mutant protein in which all CAAX processing is abolished. We show here that myristoylated H-ras C186S is a substrate for palmitoyltransferase, despite the absence of C-terminal farnesylation, and that palmitoylation is absolutely required for plasma membrane targeting of myristoylated H-ras. Similarly, the polybasic domain is required for specific plasma membrane targeting of myristoylated K-ras. In contrast, the combination of myristoylation plus farnesylation results in the mislocalization of Ras to numerous intracellular membranes. Ras that is only myristoylated does not bind with a high affinity to any membrane. The specific targeting of Ras to the plasma membrane is therefore critically dependent on signals that are contained in the hypervariable domain but can be supported by N-terminal myristoylation or C-terminal prenylation. Interestingly, oncogenic Ras G12V that is localized correctly to the plasma membrane leads to mitogen-activated protein kinase activation irrespective of the combination of targeting signals used for localization, whereas Ras G12V that is mislocalized to the cytosol or to other membranes activates mitogen-activated protein kinase only if the Ras protein is farnesylated.

Activation of MAP kinase kinase is necessary and sufficient for PC12 differentiation and for transformation of NIH 3T3 cells

The MAP kinase pathway is activated by a wide variety of external signals leading to cell proliferation or differentiation. However, it is not clear whether activation of this pathway is required for cellular responses or whether it is only one branch point in signal transduction. To investigate these questions, we generated constitutively activated and interfering mutants of MAP kinase kinase 1. The activated mutants stimulated PC12 cell neuronal differentiation and transformed NIH 3T3 cells. The interfering mutants inhibited growth factor-induced PC12 differentiation, growth factor stimulation of proliferation, and reverted v-src- and ras-transformed cells. These results therefore show that, depending on cellular context, activation of MAP kinase kinase is necessary and sufficient for cell differentiation or proliferation.

The effector domain of Rab6, plus a highly hydrophobic C terminus, is required for Golgi apparatus localization

C-terminal lipid modifications are essential for the interaction of Ras-related proteins with membranes. While all Ras proteins are farnesylated and some palmitoylated, the majority of other Ras-related proteins are geranylgeranylated. One such protein, Rab6, is associated with the Golgi apparatus and has a C-terminal CXC motif that is geranylgeranylated on both cysteines. We show here that farnesylation alone cannot substitute for geranylgeranylation in targeting Rab6 to the Golgi apparatus and that whereas Ras proteins that are farnesylated and palmitoylated are targeted to the plasma membrane, mutant Rab proteins that are both farnesylated and palmitoylated associate with the Golgi apparatus. Using chimeric Ras-Rab proteins, we find that there are sequences in the N-terminal 71 amino acids of Rab6 which are required for Golgi complex localization and show that these sequences comprise or include the effector domain. The C-terminal hypervariable domain is not essential for the Golgi complex targeting of Rab6 but is required to prevent prenylated and palmitoylated Rab6 from localizing to the plasma membrane. Functional analysis of these mutant Rab6 proteins in Saccharomyces cerevisiae shows that wild-type Rab6 and C-terminal mutant Rab6 proteins which localize to the Golgi apparatus in mammalian cells can complement the temperature-sensitive phenotype of ypt6 null mutants. Interestingly, therefore, the C-terminal hypervariable domain of Rab6 is not required for this protein to function in S. cerevisiae.

Specific association of activated MAP kinase kinase kinase (Raf) with the plasma membranes of ras-transformed retinal cells

Plasma membrane-enriched fractions were prepared from human embryonic retinal cells transformed with either adenovirus E1A and oncogenic ras DNA, or E1A and E1B DNA. Ras comprised 5-10% of the membrane protein from the E1A/ras transformed cells, whereas the membranes from E1A/E1B transformed cells did not overexpress Ras. The membranes from E1A/ras cells contained MAP kinase kinase kinase (MAPKKK) activity, even after washing in 0.5 M NaCl, whereas the membranes from E1A/E1B cells did not. Neither membrane fraction contained MAP kinase kinase or MAP kinase activity after washing with 0.5M NaCl. Immunoblotting experiments revealed about 10-fold more c-Raf in the membranes from E1A/ras cells than from E1A/E1B cells, and 50-60% of the MAPKKK activity in Triton X100-solubilised membranes from E1A/ras cells was immunoprecipitated with anti-Raf antibodies. A striking enrichment of c-Raf in the plasma membranes of E1A/ras cells was also demonstrated by immunocytochemistry, where it was co-localized with Ras. The MAPKKK activity in E1A/ras membranes was unaffected by incubation with protein phosphatases or by inclusion of protein phosphatase inhibitors during isolation, nor was it activated by GTP-Ras or inhibited by GDP-Ras. The results support the view that Ras and c-Raf interact with one another, but that neither c-Raf phosphorylation nor its interaction with GTP-Ras are alone sufficient for activation. The identification of MAPKKK activity in the membranes of ras-transformed cells may prove useful in elucidating the mechanism by which Raf is activated by Ras.

Management of enuresis in children

A postal survey was conducted to gather information on the enuresis service of Oxfordshire Health Authority Community Unit. This article discusses the size of the problem, treatment and knowledge and expertise. The findings are summarized in the form of a list of recommendations.

Motility of intracellular particles in rat fibroblasts is greatly enhanced by phorbol ester and by over-expression of normal p21N-ras

Particle motility in cultured rat fibroblasts was studied using video-enhanced differential interference contrast microscopy. The average velocity of large bright particles (apparent diameter about 0.5-0.7 micron) was measured in control cells and in cells treated with agents which affected targets related to signal transduction pathways. A Rat-2-derived fibroblast line transfected with a construct containing multiple copies of the N-ras proto-oncogene under the control of dexamethasone-sensitive promoter was used as a main experimental model. Dexamethasone treatment was shown to induce high levels of N-ras expression in these cells. This treatment greatly increased the average particle velocity. At the same time dexamethasone did not influence the particle motility in the non-transfected parent cells and in the cells transfected with a construct which did not contain N-ras. Phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C (PKC), also induced an approximate eightfold increase in the particle rate after several hours of incubation, while sphingosine, an inhibitor of PKC, prevented this activation. Sphingosine alone reduced the particle motility after a 20 min incubation. The particle movements were inhibited also by colcemid. These data show that the activation of N-ras and PKC produced dramatic activation of microtubule-dependent particle motility. A possible role of this activation in signal-induced alterations of cell morphology is discussed.

Sustained activation of the mitogen-activated protein (MAP) kinase cascade may be required for differentiation of PC12 cells. Comparison of the effects of nerve growth factor and epidermal growth factor

Stimulation of PC12 cells with nerve growth factor (NGF) increased mitogen-activated protein kinase kinase (MAPKK) activity > 20-fold after 5 min to a level that was largely sustained for at least 90 min. MAPKK activity was stimulated to a similar level by epidermal growth factor (EGF), but peaked at 2 min, declining thereafter and returning to basal levels after 60-90 min. Activation of MAPKK by either growth factor occurred prior to the activation of MAP kinase, consistent with MAPKK being the physiological activator of MAP kinase. The results demonstrate that the transient activation of MAPKK by EGF and its sustained activation by NGF underlies the transient and sustained activation of MAP kinase induced by EGF and NGF respectively. NGF or EGF induced the same two forms of MAPKK that were resolved on a Mono Q column. The Peak-1 MAPKK was activated initially and partially converted into the more acidic peak-2 MAPKK after prolonged growth-factor stimulation. The Peak-2 MAPKK was 20-fold more sensitive to inactivation by the catalytic subunit of protein phosphatase 2A. Stimulation with NGF caused a striking translocation of MAP kinase from the cytosol to the nucleus after 30 min, but not nuclear translocation of MAP kinase occurred after stimulation with EGF. The results suggest that sustained activation of the MAP kinase cascade may be required for MAP kinase to enter the nucleus, where it may initiate the gene transcription events required for neuronal differentiation of PC12 cells.