The relationship between the laboratory diagnosis of Lyme neuroborreliosis and climate factors in Kalmar County Sweden - an overview between 2008 and 2019

The purpose of this study was to describe the epidemiology of Lyme neuroborreliosis (LNB) in Kalmar County, in southern Sweden, between 2008 and 2019, and to analyse the relationship between the LNB incidence and climate factors. Data containing cerebrospinal fluid (CSF) cell counts and borrelia CSF/serum antibody index results was received from the departments of clinical chemistry and microbiology at Kalmar County hospital. For this study, we defined LNB as a case with a positive borrelia antibody CSF/serum index and CSF leukocytes > 5 × 10⁶/L. Climate data including mean temperature, humidity and precipitation covering Kalmar County was collected from the Swedish Meteorological and Hydrological Institute. A total of 5051 paired serum-CSF samples from 4835 patients were investigated of which 251 laboratory LNB cases were found. The average annual LNB incidence in Kalmar County 2008–2019 was 8.8 cases per 100,000 inhabitants. Positive relationships were observed between mean temperature and LNB incidence (p < 0.001) as well as precipitation and LNB incidence (p = 0.003), both with a one calendar month delay. The results suggest an association between climate factors such as mean temperature and precipitation and LNB incidence, presumably through increased/decreased human-tick interactions. This calls for increased awareness of LNB in both the short perspective after periods of warmth and heavy precipitation as well as in a longer perspective in relation to possible climate change. Further studies with larger study groups, covering other geographical areas and over longer periods of time are needed to confirm these findings.

Developmental SHP2 dysfunction underlies cardiac hypertrophy in Noonan syndrome with multiple lentigines

Hypertrophic cardiomyopathy is a common cause of mortality in congenital heart disease (CHD). Many gene abnormalities are associated with cardiac hypertrophy, but their function in cardiac development is not well understood. Loss-of-function mutations in PTPN11, which encodes the protein tyrosine phosphatase (PTP) SHP2, are implicated in CHD and cause Noonan syndrome with multiple lentigines (NSML), a condition that often presents with cardiac hypertrophic defects. Here, we found that NSML-associated hypertrophy stems from aberrant signaling mechanisms originating in developing endocardium. Trabeculation and valvular hyperplasia were diminished in hearts of embryonic mice expressing a human NSML-associated variant of SHP2, and these defects were recapitulated in mice expressing NSML-associated SHP2 specifically in endothelial, but not myocardial or neural crest, cells. In contrast, mice with myocardial- but not endothelial-specific NSML SHP2 expression developed ventricular septal defects, suggesting that NSML-associated mutations have both cell-autonomous and nonautonomous functions in cardiac development. However, only endothelial-specific expression of NSML-associated SHP2 induced adult-onset cardiac hypertrophy. Further, embryos expressing the NSML-associated SHP2 mutation exhibited aberrant AKT activity and decreased downstream forkhead box P1 (FOXP1)/FGF and NOTCH1/EPHB2 signaling, indicating that SHP2 is required for regulating reciprocal crosstalk between developing endocardium and myocardium. Together, our data provide functional and disease-based evidence that aberrant SHP2 signaling during cardiac development leads to CHD and adult-onset heart hypertrophy.

RhoA signaling in cardiomyocytes protects against stress-induced heart failure but facilitates cardiac fibrosis

The Ras-related guanosine triphosphatase RhoA mediates pathological cardiac hypertrophy, but also promotes cell survival and is cardioprotective after ischemia/reperfusion injury. To understand how RhoA mediates these opposing roles in the myocardium, we generated mice with a cardiomyocyte-specific deletion of RhoA. Under normal conditions, the hearts from these mice showed functional, structural, and growth parameters similar to control mice. Additionally, the hearts of the cardiomyocyte-specific, RhoA-deficient mice subjected to transverse aortic constriction (TAC)-a procedure that induces pressure overload and, if prolonged, heart failure-exhibited a similar amount of hypertrophy as those of the wild-type mice subjected to TAC. Thus, neither normal cardiac homeostasis nor the initiation of compensatory hypertrophy required RhoA in cardiomyocytes. However, in response to chronic TAC, hearts from mice with cardiomyocyte-specific deletion of RhoA showed greater dilation, with thinner ventricular walls and larger chamber dimensions, and more impaired contractile function than those from control mice subjected to chronic TAC. These effects were associated with aberrant calcium signaling, as well as decreased activity of extracellular signal-regulated kinases 1 and 2 (ERK1/2) and AKT. In addition, hearts from mice with cardiomyocyte-specific RhoA deficiency also showed less fibrosis in response to chronic TAC, with decreased transcriptional activation of genes involved in fibrosis, including myocardin response transcription factor (MRTF) and serum response factor (SRF), suggesting that the fibrotic response to stress in the heart depends on cardiomyocyte-specific RhoA signaling. Our data indicated that RhoA regulates multiple pathways in cardiomyocytes, mediating both cardioprotective (hypertrophy without dilation) and cardio-deleterious effects (fibrosis).

Abstract 200: Cardiomyocyte-specific Deletion Of Rhoa Accelerates Heart Failure But Prevents Cardiac Fibrosis In Response To Pressure-overload

Heart failure is a progressive disease characterized by loss of cardiac contractility, interstitial fibrosis, and chamber remodeling. Though several signaling pathways have been identified, the precise mechanisms involved in regulating pathological cardiac responses remain unclear. The Ras-related small G protein RhoA is an identified mediator of in vivo pathological hypertrophy. However, it also promotes cell survival and is cardioprotective after ischemia/repurfusion injury. Therefore, to determine the molecular mechanisms that underlie these opposing roles for RhoA in the myocardium, we generated mice with cardiomyocyte-specific deletion of RhoA (RhoAfl/fl-αMHC-Cre). As compared to wildtype mice, hearts from RhoAfl/fl-αMHC-Cre mice showed similar functional, structural, and growth parameters, both at baseline and in response to acute transverse aortic constriction (TAC) (2wks), suggesting RhoA plays no major role in either homeostatic or acute stress-induced cardiac conditions. However, after exposure to chronic TAC for 8wks, hearts from RhoAfl/fl-αMHC-Cre mice developed an accelerated dilation, with significant loss of contractile function. Mechanistically, cardiomyocyte-specific loss of RhoA reduced ERK1/2 activation and perturbed agonist-evoked calcium cycling, through aberrant IP3 and DAG signaling, indicating that RhoA mediates its cardioprotective effects through regulation of these pathways. Despite this, and surprisingly, hearts from RhoAfl/fl-αMHC mice also showed significantly decreased TAC-induced cardiac fibrosis, with a demonstrated decrease in transcriptional activation of genes involved in the fibrotic response, including the serum response factor (SRF), as well as the secreted factor BMP7. Taken together, our data reveal an interesting, yet highly complex signaling and regulatory mechanism for RhoA, whereby RhoA signaling is both cardioprotective against development of heart failure in response to chronic stress, but also cardio-deleterious through its capacity to activate pro-fibrotic genes.

Abstract 196: Adult-onset Cardiac Hypertrophy In LEOPARD Syndrome Is Caused By Both Cell Autonomous And Non-autonomous Effects That Occur During Development

Loss of function mutations in PTPN11 , the gene encoding the protein tyrosine phosphatase SHP2, cause LEOPARD Syndrome (LS), an autosomal dominant disorder with multiple cardiac defects, including hypertrophy. However, the mechanisms by which the LS mutants cause cardiac disease and regulate development remain unclear. Here, we utilized our inducible LS mouse model to determine whether LS mutations affect onset of cardiac hypertrophy via aberrant regulation of developmental processes. We examined hearts from wildtype (WT) or ubiquitously-expressing heterozygous LS (LS/+) and homozygous LS (LS/LS) embryos. As compared to WT, both LS/+ and LS/LS developing hearts showed diminished trabeculation, valvular hyperplasia and ventricular septal defects. In addition, LS/LS embryos had dextraposition of the aorta, leading to embryonic lethality. Gene expression analysis revealed that LS mutant hearts had decreased Foxp1/Fgf and Notch1/EphB2 signaling, suggesting perturbation of the reciprocal cross-talk between the developing endocardium and myocardium

To assess this directly and to determine the in-vivo effects of lineage-specific LS expression during development, we generated, endothelial (Tie2)-, myocardial (Nkx2.5)- and neural crest (Wnt1)- specific LS/+ expressing mice. Surprisingly, the majority of LS cardiac defects, including the adult-onset cardiac hypertrophy, were recapitulated by expression of endocardial-specific LS alone, suggesting a functional necessity for the endocardium in hypertrophy of the heart. Moreover, though myocardial-specific expression of LS showed only minor developmental effects, these mice still recapitulated the adult-onset cardiac hypertrophy. Interestingly, no cardiac abnormalities were observed in the neural crest-specific expressing LS mice. Taken together, our data indicate that the LS mutations affect both cell autonomous and non-autonomous pathways necessary for the reciprocal cross-talk between endocardium and myocardium, and, importantly, that the adult-onset hypertrophy in LS is caused by aberrant signaling effects that occur during cardiac development.

Cardiomyocyte ATP release through pannexin 1 aids in early fibroblast activation

Fibrosis following myocardial infarction is associated with increases in arrhythmias and sudden cardiac death. Initial steps in the development of fibrosis are not clear; however, it is likely that cardiac fibroblasts play an important role. In immune cells, ATP release from pannexin 1 (Panx1) channels acts as a paracrine signal initiating activation of innate immunity. ATP has been shown in noncardiac systems to initiate fibroblast activation. Therefore, we propose that ATP release through Panx1 channels and subsequent fibroblast activation in the heart drives the development of fibrosis in the heart following myocardial infarction. We identified for the first time that Panx1 is localized within sarcolemmal membranes of canine cardiac myocytes where it directly interacts with the postsynaptic density 95/Drosophila disk large/zonula occludens-1-containing scaffolding protein synapse-associated protein 97 via its carboxyl terminal domain (amino acids 300-357). Induced ischemia rapidly increased glycosylation of Panx1, resulting in increased trafficking to the plasma membrane as well as increased interaction with synapse-associated protein 97. Cellular stress enhanced ATP release from myocyte Panx1 channels, which, in turn, causes fibroblast transformation to the activated myofibroblast phenotype via activation of the MAPK and p53 pathways, both of which are involved in the development of cardiac fibrosis. ATP release through Panx1 channels in cardiac myocytes during ischemia may be an early paracrine event leading to profibrotic responses to ischemic cardiac injury.

Abstract P288: ATP Signaling Stimulates Fibroblast Activation: The Role of Pannexin1 Channels in Fibrosis

BACKGROUND-We have shown that Pannexin1 (Panx1), a novel ATP channel, is found in ventricular cardiac myocytes and upregulated on myocyte sarcolemmal membranes during acute ischemia. We hypothesize that the channel is part of a protein complex that plays a role in downstream cell signaling post myocardial infarction (MI).

METHODS-Using a canine model of MI, where the left anterior descending coronary artery is occluded (CO) we examined epicardial tissue from hearts subjected to 0–3 hrs of CO. Immunoprecipitation (IP) with subsequent silver stain studies revealed novel binding partners for Panx1. Co-immunoprecipitation studies (Co-IP) were performed to confirm Panx1 binding partners. In vitro dye uptake studies and ATP assays were used to determine the function of Panx1 channels under hypoxic conditions.

RESULTS-IP followed by silver staining revealed multiple potential binding partners for Panx1 in the heart. Following 3 hrs CO some interactions increased while others decreased. Co-immunoprecipitation identified one of these partners for Panx1 as the MAGUK scaffolding protein SAP97, an interaction that is significantly increased following 3 hr CO (n=3, p<0.05). Immunostaining showed that CO increased trafficking and stabilization of Panx1 channels at the cell membranes. In vitro dye uptake studies show that cells increase dye uptake following hypoxia, an event that is blocked by the Panx1 channel blocker, Probenecid. Hypoxia also causes increased ATP release likely due to opening of Panx1 channels. ATP release activated fibroblasts and stimulated early fibrosis signaling.

CONCLUSIONS-Our data show the presence of a Panx1 protein complex in cardiac myocytes that is scaffolded at the cell membranes by SAP97. Under cellular stress Panx1 channels release ATP to induce early fibrotic events. We We conclude that Panx1 plays a key functional role in ATP signaling and formation of fibrosis in the post-MI heart.

Rapamycin reverses hypertrophic cardiomyopathy in a mouse model of LEOPARD syndrome-associated PTPN11 mutation

LEOPARD syndrome (LS) is an autosomal dominant "RASopathy" that manifests with congenital heart disease. Nearly all cases of LS are caused by catalytically inactivating mutations in the protein tyrosine phosphatase (PTP), non-receptor type 11 (PTPN11) gene that encodes the SH2 domain-containing PTP-2 (SHP2). RASopathies typically affect components of the RAS/MAPK pathway, yet it remains unclear how PTPN11 mutations alter cellular signaling to produce LS phenotypes. We therefore generated knockin mice harboring the Ptpn11 mutation Y279C, one of the most common LS alleles. Ptpn11(Y279C/+) (LS/+) mice recapitulated the human disorder, with short stature, craniofacial dysmorphia, and morphologic, histologic, echocardiographic, and molecular evidence of hypertrophic cardiomyopathy (HCM). Heart and/or cardiomyocyte lysates from LS/+ mice showed enhanced binding of Shp2 to Irs1, decreased Shp2 catalytic activity, and abrogated agonist-evoked Erk/Mapk signaling. LS/+ mice also exhibited increased basal and agonist-induced Akt and mTor activity. The cardiac defects in LS/+ mice were completely reversed by treatment with rapamycin, an inhibitor of mTOR. Our results demonstrate that LS mutations have dominant-negative effects in vivo, identify enhanced mTOR activity as critical for causing LS-associated HCM, and suggest that TOR inhibitors be considered for treatment of HCM in LS patients.

Attitudes of a group of primary school teachers towards the educational inclusion of hearing-impaired learners in regular classrooms

Research has clearly demonstrated a link between the attitudes of regular education teachers and the success of inclusion of learners with special educational needs. Therefore, the present study aimed to investigate the attitudes of a group of junior primary school teachers from the Gauteng area towards the inclusion of hearing-impaired children into regular classes. A survey research design was employed which utilized a questionnaire as the research tool. Analysis of results indicated that the teachers surveyed were relatively positive in their attitudes towards inclusion. Greater exposure to disability in terms of training and experience was related to more positive attitudes. Similarly, more positive attitudes were related to greater perceived competence in teaching hearing-impaired pupils. All of the teachers surveyed felt that speech-language pathologists and audiologists (SLPs & As) should be involved in facilitating inclusion of hearing-impaired children. Many of the respondents expressed concern regarding their lack of training, knowledge and skills. The findings from the research project highlight the need for an adequate training and support system for teachers prior to the implementation of an inclusive educational policy, and the potential role of SLPs & As in this regard.

The Drosophila Medea gene is required downstream of dpp and encodes a functional homolog of human Smad4

The Transforming Growth Factor-beta superfamily member decapentaplegic (dpp) acts as an extracellular morphogen to pattern the embryonic ectoderm of the Drosophila embryo. To identify components of the dpp signaling pathway, we screened for mutations that act as dominant maternal enhancers of a weak allele of the dpp target gene zerknLllt. In this screen, we recovered new alleles of the Mothers against dpp (Mad) and Medea genes. Phenotypic analysis of the new Medea mutations indicates that Medea, like Mad, is required for both embryonic and imaginal disc patterning. Genetic analysis suggests that Medea may have two independently mutable functions in patterning the embryonic ectoderm. Complete elimination of maternal and zygotic Medea activity in the early embryo results in a ventralized phenotype identical to that of null dpp mutants, indicating that Medea is required for all dpp-dependent signaling in embryonic dorsal-ventral patterning. Injection of mRNAs encoding DPP or a constitutively activated form of the DPP receptor, Thick veins, into embryos lacking all Medea activity failed to induce formation of any dorsal cell fates, demonstrating that Medea acts downstream of the thick veins receptor. We cloned Medea and found that it encodes a protein with striking sequence similarity to human SMAD4. Moreover, injection of human SMAD4 mRNA into embryos lacking all Medea activity conferred phenotypic rescue of the dorsal-ventral pattern, demonstrating conservation of function between the two gene products.

fusca3: A Heterochronic Mutation Affecting Late Embryo Development in Arabidopsis

Molecular studies of late embryogenesis and seed development have emphasized differential gene expression as a means of identifying discrete stages of embryogenesis. Little has been done to identify factors that regulate the length of a given developmental stage or the degree of overlap between adjacent developmental programs. We designed a genetic screen to identify mutations that disrupt late embryo development in Arabidopsis without loss of hormonal responses. One such mutation, fusca3 (fus3), alters late embryo functions, such as the establishment of dormancy and desiccation tolerance, and reduces storage protein levels. fus3 cotyledons bear trichomes, and their ultrastructure is similar to that of leaf primordia. Immature fus3 embryos enter germinative development, and the shoot apical meristems develop leaf primordia before seed desiccation begins. The cotyledons resemble leaf primordia, yet retain some cotyledon characteristics; thus, cotyledon- and leaf-specific functions are expressed simultaneously. Together, these observations are consistent with a heterochronic interpretation of the fus3 mutation.

fusca3: A Heterochronic Mutation Affecting Late Embryo Development in Arabidopsis

Molecular studies of late embryogenesis and seed development have emphasized differential gene expression as a means of identifying discrete stages of embryogenesis. Little has been done to identify factors that regulate the length of a given developmental stage or the degree of overlap between adjacent developmental programs. We designed a genetic screen to identify mutations that disrupt late embryo development in Arabidopsis without loss of hormonal responses. One such mutation, fusca3 (fus3), alters late embryo functions, such as the establishment of dormancy and desiccation tolerance, and reduces storage protein levels. fus3 cotyledons bear trichomes, and their ultrastructure is similar to that of leaf primordia. Immature fus3 embryos enter germinative development, and the shoot apical meristems develop leaf primordia before seed desiccation begins. The cotyledons resemble leaf primordia, yet retain some cotyledon characteristics; thus, cotyledon- and leaf-specific functions are expressed simultaneously. Together, these observations are consistent with a heterochronic interpretation of the fus3 mutation.

Isolation of an internal deletion mutant of the Arabidopsis thaliana ABI3 gene

An Arabidopsis thaliana mutant that produces green seeds that are highly insensitive to exogenous ABA, non-dormant and severely desiccation intolerant was isolated from a population of fast neutron-irradiated seeds. Molecular and genetic analysis of this mutant shows that these phenotypes are caused by an internal deletion of approximately one third of the ABI3 gene. Therefore abi3 mutants with the above phenotypes are representative of null alleles at this locus.

Trypanosoma brucei: characterization of protein kinases that are capable of autophosphorylation in vitro

Autophosphorylation by protein kinases has been implicated as an important control mechanism in signal transduction and growth regulatory pathways in mammalian cells. We have set out to investigate whether any such autophosphorylating protein kinase activities can be found in Trypanosoma brucei. In order to do this, we have developed a system for characterizing such protein kinase activities using an in vitro assay. This assay was carried out by fractionation of trypanosome lysates using isoelectric focusing gel electrophoresis followed by incubation of the gel in gamma 32P-labelled nucleotide triphosphate and subsequent autoradiography. We have identified two classes of autophosphorylating protein kinase activities. In the first class all were dependent on ATP as the phosphate donor substrate and were all found to have a molecular size of 60 kDa. Differences in the activity of these protein kinases were observed between the bloodstream and procyclic life-cycle stages. Furthermore, the addition of mammalian epidermal growth factor to bloodstream stage lysates stimulated an additional activity. The second class of autophosphorylating protein kinases utilized GTP as the phosphate donor and were all found to be 90 kDa in size. Stage-specific differences were also observed in the activity of these protein kinases.

Characterisation of protein kinase C like activities in Trypanosoma brucei

Protein kinase activities in bloodstream and procyclic forms of Trypanosoma brucei have been partially purified and characterised. Cytosolic extracts were separated on DEAE-cellulose and assayed for the ability to phosphorylate histone in the presence of Ca2+ and diacylglycerol. Five peaks of activity were identified in bloodstream T. brucei and only three in procyclic lysates. One of the kinases present in bloodstream T. brucei shares may characteristics with mammalian protein kinase C. Further characterisation of the kinases using an in situ assay after separating proteins by isoelectric focussing confirmed that the kinases present in bloodstream and procyclic stages differed in properties and either bloodstream kinases are more stable or greater in number than procyclic kinases. A protein present in bloodstream T. brucei was shown by Western blot analysis to contain an epitope recognized by a monoclonal antibody raised against mammalian protein kinase C. We thus conclude that the protein kinases are differentially regulated between the two stages of the parasite and that the bloodstream stage has a protein kinase C homologue. The implications of these findings in relation to a cellular signalling pathway in trypanosomes is discussed.

Wheelchair use by ambulatory nursing home residents

In a survey of wheelchair use in two nursing homes, the authors found a substantial number of cognitively intact nursing home residents who walked, but who also used a wheelchair. Using chart review and interviews with the residents, it was found that multiple physical factors, including pain, strength, endurance, vision and balance, and multiple social and environmental factors, including the fear of falling, were related to the resident's decision to use a wheelchair as an alternative means of mobility. A physical examination focused on aspects of mobility was completed on each resident and was intended to characterize the physical limitations in groups studied. In the nursing home environment, use of the wheelchair is viewed by the residents as a self-initiated choice which the residents believed significantly enhanced their sense of well-being. Finally, there was minimal recognition of mobility as a problem on the part of the medical and nursing staff. The study raises a number of important issues concerning walking versus wheelchair use in the nursing home.

Variation in arbovirus infection rates in species of birds sampled in a serological survey during an encephalitis epidemic in the Murray Valley of South-eastern Australia, February 1974

There was extensive and exuberant breeding of waterbirds before and during an epidemic of arboviral encephalitis in the Murray Valley of south eastern Australia in 1974. As estimated by haemagglutination inhibition tests on 432 bird sera collected between 4th and 13th February, 1974, infection with Murray Valley encephalitis virus, Kunjin virus and possibly other flaviviruses was concentrated in species of the Order Ciconiiformes (55% positive) and Pelecaniformes (41%), compared with only 5% in Anseriformes. Although Sindbis virus infections were also highest in these 2 Orders (56% and 46%, respectively), the incidence of antibodies was spread more uniformly through other Orders than with the flaviviruses: e.g. Anseriformes, 33%, Podicipitiformes, 27%. As viruses were recovered virtually only from Culex annulirostris mosquitoes, the different patterns of infection seem unrelated to host preference by mosquito species or behavioural response to mosquito attack, and suggest a specific relationship between MVE/KUN and Ciconiiformes and Pelecaniformes. The highest infection rate was 22/25 in mature rufous night herons (formerly nankeen night herons) Nycticorax calendonicus, and here tolerance to mosquito attack was probably a contributing factor. Assays of sera from 13 horses indicated high infection rates both alphaviruses and flaviviruses.

The Occurence of the Dusky Field-rat, Rattus sordidus (Rodentia : Muridae), in New South Wales

Description and measurements are given of two young female R. sordidus trapped near Evans Head, N.S.W., in 1968 and 1970.

Macquarie Island: the introduction of the European rabbit flea Spilopsyllus cuniculi (Dale) as a possible vector for myxomatosis

The European rabbit flea Spilopsyllus cuniculi (Dale) was first released on Macquarie Island in December 1968. The flea has survived and bred on the island and about 30% of the rabbits sampled from the original release area in January 1972 were flea-infested.