Bilateral axillary web syndrome in a patient with primary lymphoedema of upper limbs and non-Hodgkin lymphoma

Primary lymphoedema, axillary web syndrome (AWS) and yellow nail syndrome may be related. Mr B is a 66-year-old gentleman with genital lymphoedema and lymphoedema of all four extremities. In 2023, he was diagnosed with non-Hodgkin lymphoma and also underwent cardiac surgery. In November 2023, he completed an inpatient rehabilitation at the Földi clinic in Germany, where he received intensive treatment for his lymphoedema and was also diagnosed with bilateral AWS. The presence of AWS in a patient with primary lymphoedema and no history of axillary surgery is unique. Although AWS typically presents after axillary surgery, this case highlights that it can also occur in patients without lymph node surgery. While the precise cause of this presentation of AWS is not known, it may be connected to yellow nail syndrome or potentially the recent chemotherapy treatment. This article will describe the clinical case, highlighting the need for further research on AWS present in primary lymphoedema.

Seasonal Variation in Upper Limb Size, Volume, Fluid Distribution, and Lymphedema Diagnosis, Following Breast Cancer Treatment

Background: Breast cancer-related lymphedema (BCRL) is a common complication of breast cancer treatment. Anecdotal and qualitative research suggests that heat and hot weather cause an exacerbation of BCRL; however, there is little quantitative evidence to support this. The aim of this article is to investigate the relationship between seasonal climate variation and limb size, volume, fluid distribution, and diagnosis in women following breast cancer treatment. Methods and Results: Women older than the age of 35 years who had undergone treatment for breast cancer were invited to participate. Twenty-five women aged between 38 and 82 years were recruited. Seventy-two percent received surgery, radiation therapy, and chemotherapy as part of their breast cancer treatment. Participants completed anthropometric, circumferential, and bioimpedance measures and a survey on three occasions: November (spring), February (summer), and June (winter). Diagnostic criteria of >2 cm and >200 mL difference between the affected and unaffected arm, and a positive bioimpedance ratio of >1.139 for a dominant arm and >1.066 for nondominant arm was applied across the three measurement occasions. No significant correlation between seasonal variation in climate and upper limb size, volume, or fluid distribution were found in women diagnosed with or at risk of developing BCRL. Lymphedema diagnosis depends on the season and diagnostic measurement tool utilized. Conclusion: There was no statistically significant variation in limb size, volume, or fluid distribution in this population across spring, summer, and winter, although there were linked trends in these values. The diagnosis of lymphedema, however, varied between individual participants throughout the year. This has important implications for the implementation/commencement of treatment and management. Further research with a larger population in different climates is required to explore the status of women with respect to BCRL. The use of common clinical diagnostic criteria did not result in consistent diagnostic classification of BCRL for the women involved in this study.

Co‐creation of a student‐implemented allied health service in a First Nations remote community of East Arnhem Land, Australia

OBJECTIVES

To co-create a culturally responsive student-implemented allied health service in a First Nations remote community and to determine the feasibility and acceptability of the service.

DESIGN

Co-creation involved a pragmatic iterative process, based on participatory action research approaches. Feasibility and acceptability were determined using a mixed-method pre/postdesign.

SETTING

The service was in Nhulunbuy, Yirrkala and surrounding remote First Nations communities of East Arnhem Land, Northern Territory, Australia.

PARTICIPANTS

Co-creation of the service was facilitated by the Northern Australia Research Network, guided by Indigenous Allied Health Australia leadership, with East Arnhem local community organisations and community members. Co-creation of the day-to-day service model involved local cultural consultants, service users and their families, staff of community organisations, students, supervisors, placement coordinators and a site administrator.

FINDINGS

A reciprocal learning service model was co-created in which culturally responsive practice was embedded. The service was feasible and acceptable: it was delivered as intended; resources were adequate; the service management system was workable; and the service was acceptable. Health outcome measures, however, were not appropriate to demonstrate impact, particularly through the lens of the people of East Arnhem. Recommendations for the service included: continuing the reciprocal learning service model in the long term; expanding to include all age groups; and connecting with visiting and community-based services.

CONCLUSION

The co-created service was feasible and acceptable. To demonstrate the impact of the service, measures of health service impact that are important to First Nations people living in remote communities of northern Australia are required.

Marŋgithirri guŋga'yunarawu ga guŋga'yunyarawu marŋgithinyarawu Learning to connect and connecting to learn: Preparing the rural and remote allied health workforce through a co-created student-implemented service in East Arnhem, Australia

OBJECTIVES

To explore the process of learning for allied health students providing a student-implemented service for older Yolŋu in remote East Arnhem, Northern Territory, Australia.

DESIGN

An exploratory qualitative study following an 8-week student-implemented service.

SETTING

Nhulunbuy and Yirrkala and surrounding remote Aboriginal communities of the East Arnhem Region of the Northern Territory.

PARTICIPANTS

Data were collected from: 4 students who implemented the service; 4 professional supervisors, 3 placement coordinators, a Yolŋu cultural consultant and a care manager from a local community organisation, all of whom supported implementation of the service; and 7 older Yolŋu and their families who were recipients of the service.

INTERVENTIONS

A student-implemented service for older Yolŋu delivered by allied health students from James Cook University. Clinical, cultural and pastoral supervision and support was provided by Flinders University, James Cook University, Indigenous Allied Health Australia and 2 Yolŋu cultural consultants and 2 local community organisations.

MAIN OUTCOME MEASURES

Semi-structured interviews with those who implemented, supported and received the service. Data were analysed thematically using an inductive approach.

RESULTS

'Learning to connect and connecting to learn' described how allied health students were learning to provide a service for older Yolŋu. Four interrelated processes connected their learning: 'preparing and supporting', 'bonding and responding', 'growing and enriching' and 'working and weaving'.

CONCLUSION

The co-created student-implemented service provided a unique learning opportunity for allied health students on how to provide a culturally safe service in a remote Aboriginal community in northern Australia.

Workplace locations of allied health and nursing graduates who undertook a placement in the Northern Territory of Australia from 2016 to 2019: An observational cohort study

OBJECTIVE

The aim of the study is to determine the current work locations of allied health professionals and nurses who undertook a student placement in the Northern Territory of Australia from 2016-2019.

DESIGN

An observational cohort study was conducted in October 2020, with students emailed a link to an on-line survey, plus two reminders.

SETTING

Primary health care in the Northern Territory of Australia.

PARTICIPANTS

All allied health and nursing students who undertook a student learning placement in the Northern Territory from 2016-2019 (n = 1936).

MAIN OUTCOME MEASURES

Practicing nurses and allied health professionals were asked about their work history and locations (coded using the Modified Monash Model of remoteness and population size).

RESULTS

The response rate was 14.2% (275/1936 students). Most respondents reported that their placement positively influenced them to consider working: in a rural or remote location (76%), in the Northern Territory (81%), and with marginalised or under-served populations (74%). Of the respondents, 224 had graduated and 203 were currently working in their health profession. A total of 31.4% of respondents reported that they had worked in a remote or rural location after graduation.

CONCLUSIONS

The student placement had a positive effect on the likelihood of students working in a rural or remote location. A focus on recruiting students with a remote upbringing/background and offering longer placements would likely be successful in helping build the health professional workforce in remote locations.

Characteristics of nursing and allied health student placements in the Northern Territory over time (2017-2019) and placement satisfaction

OBJECTIVE

Assess nursing and allied health student satisfaction with their remote Northern Territory integrated learning placement and consideration of future rural/remote work Describe the characteristics of these students Examine changes in student characteristics over time.

DESIGN

A cross-sectional survey of students and a review of student placement data.

SETTING

Northern Territory, Australia.

PARTICIPANTS

Former students having a work integrated learning placement of more than 1 week in the Northern Territory from 2017 to 2019.

MAIN OUTCOME MEASURE(S)

Agreement with the statements 'This placement has encouraged me to consider living and working in a rural or remote location after I graduate' and 'Overall, I was satisfied with my placement.' The administrative record review examined student numbers, and placement length over time.

RESULTS

A total of 341 students responded to the online survey. Overall satisfaction with the placement was very high (93%), and 84% agreed/strongly agreed that the placement had encouraged them to consider working in a rural or remote setting. High-quality clinical supervision and educational resources were associated with overall placement satisfaction. Overall placement satisfaction, prior interest in working remotely and satisfaction with educational resources were associated with consideration of working remotely. The number of students having a placement increased by 29% in 2017 to 2019. The number of placement weeks also increased (35%).

CONCLUSIONS

The number/placement time of nursing and allied health students has increased in the NT. Satisfaction with remote work integrated learning placements is an the important pathway to growing a local health professional workforce in remote and rural settings.

Health Professional Student Placements and Workforce Location Outcomes: Protocol of an Observational Cohort Study

Background

The successful recruitment and retention of health professionals to rural and remote areas of Australia is a health policy priority. Nursing or allied health professional students’ learning placements in the Northern Territory (NT) of Australia, most of which is considered remote, may influence rural or remote work location decisions.

Objective

The aim of this study is to determine where allied health professionals and nurses who have had a student placement in the NT of Australia end up practicing.

Methods

This research is an observational cohort study, with data collection occurring at baseline and then repeated annually over 10 years (ie, 2017-2018 to 2029). The baseline data collection includes a demographic profile of allied health and nursing students and their evaluations of their NT placements using a nationally consistent questionnaire (ie, the Student Satisfaction Survey). The Work Location Survey, which will be administered annually, will track work location and the influences on work location decisions.

Results

This study will generate unique data on the remote and rural work locations of nursing and allied health professional students who had a placement in the NT of Australia. It will be able to determine what are the most important characteristics of those who take up remote and rural employment, even if outside of the NT, and to identify barriers to remote employment.

Conclusions

This study will add knowledge to the literature regarding rates of allied health and nursing professionals working in remote or rural settings following remote or rural learning placements. The results will be of interest to government and remote health workforce planners.

Trial Registration

Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12620000797976; https://www.anzctr.org.au/ACTRN12620000797976.aspx

International Registered Report Identifier (IRRID)

PRR1-10.2196/21832

First-year predictors of health-related quality of life changes in short-statured children treated with human growth hormone

PURPOSE

Little attention has been directed towards examining the impact of predictors on change in health-related quality of life (HRQOL) within the course of growth hormone (GH) treatment in pediatric short stature. We aimed to assess changes in HRQOL and its sociodemographic, clinical and psychosocial predictors in children and adolescents diagnosed with growth hormone deficiency (GHD), and born short for gestational age (SGA) before and 12-month after start of GH treatment from the parents' perspective. Results were compared with an untreated group with idiopathic short stature (ISS). In this prospective multicenter study, 152 parents of children/adolescents (aged 4-18 years) provided data on their children's HRQOL at baseline and at 12-month follow-up.

METHOD

Repeated-measures multivariate analyses of covariance were performed to examine parent-reported HRQOL changes from baseline to 1-year after treatment and hierarchical linear regressions to identify the predictors of HRQOL changes.

RESULTS

Results showed that parents of children that were treated with GH report an increase in their children's HRQOL after 1 year. Changes in HRQOL were mostly explained by psychosocial predictors followed by sociodemographic and clinical variables. Specifically, the diagnosis SGA significantly predicted a greater increase in parent-reported HRQOL. Furthermore, a lower caregiving burden significantly predicted a decrease in parent-reported HRQOL.

CONCLUSION

In conclusion, a substantial percentage of explained variance in HRQOL relates to psychosocial and sociodemographic predictors. However, there appears to be other important factors that are predictors of HRQOL, which need to be determined in large, population-based samples.

Comparative characterization of two galectins excreted-secreted from intestine-dwelling parasitic versus free-living females of the soil-transmitted nematode Strongyloides

Helminths are complex pathogens that ensure their long-term survival by influencing the immune responses of their host. Excretory/secretory products (ESP) can exert immunoregulatory effects which foster parasite survival. Galectins represent a widespread group of β-galactoside-binding proteins which are involved in a multitude of biological processes operative in parasite-host interaction. We had earlier identified seven galectins in Strongyloides ratti, four of them detected in the ESP of distinct developmental stages of the parasite. In the present report, we focused on the characterization of two of them, Sr-galectin-1 (Sr-Gal-1) and Sr-galectin-3 (Sr-Gal-3). While Sr-Gal-3 expression was strongest in parasitic females, Sr-Gal-1 was predominantly expressed in free-living females. Both proteins were cloned and recombinantly expressed in an E. coli expression system. Their glycan-binding activity was verified by haemagglutination and glycan array analysis. Furthermore, primary immunological activities of the Sr-galectins were initially investigated by the application of an in vitro mucosal 3D-culture model, comprising of mucosa-associated epithelial and dendritic cells. The Sr-galectins stimulated preferentially the release of the type 2 cytokines thymic stromal lymphopoietin and IL-22, a first indication for immunoregulatory activity. In addition, the Sr-galectins dose-dependently fostered cell migration. Our results confirm the importance of these carbohydrate-binding proteins in host-parasite-interaction by indicating possible interaction with the host mucosa-associated cells.

The effect of 5-HTTLPR and a serotonergic multi-marker score on amygdala, prefrontal and anterior cingulate cortex reactivity and habituation in a large, healthy fMRI cohort

Major depressive disorder (MDD) is characterized by low mood for at least two weeks. Impaired emotion regulation has been suggested to be the consequence of dysfunctional serotonergic regulation of limbic and prefrontal regions, especially the amygdala, the anterior cingulate cortex (ACC) and the prefrontal cortex (PFC). The impact of genetic variation on brain function can be investigated with intermediate phenotypes. A suggested intermediate phenotype of MDD is emotion recognition: The 5-HTTLPR polymorphism of SLC6A4 as well as other serotonergic genes have been associated with amygdala and prefrontal function during emotion recognition. Previously, it has been suggested that habituation is a more reliable index of emotion recognition than functional activation. We examined the relationship of genes involved in serotonergic signaling with amygdala as well as prefrontal functional activation and habituation during an emotion recognition task in 171 healthy subjects. While effects of 5-HTTLPR and of a serotonergic multi-marker score (5-HTTLPR, TPH1(rs1800532), TPH2(rs4570625), HTR1A(rs6295) and HTR2A(rs6311)) on amygdala activation did not withstand correction for multiple regions of interest, we observed a strong correlation of the multi-marker score and habituation in the amygdala, DLPFC, and ACC. We replicated a well-studied intermediate phenotype for association with 5-HTTLPR and provided additional evidence for polygenic involvement. Furthermore, we showed that task habituation may be influenced by genetic variation in serotonergic signaling, particularly by a serotonergic multi-marker score. We provided preliminary evidence that PFC activation is an important intermediate phenotype of MDD. Future studies are needed to corroborate the results in larger samples.

Development and pilot-testing of a condition-specific instrument to assess the quality-of-life in children and adolescents born with esophageal atresia

The survival rate of children with esophageal atresia has today reached 95%. However, children are at risk of chronic morbidity related to esophageal and respiratory dysfunction, and associated anomalies. This study describes the pilot testing of a condition-specific health-related quality-of-life instrument for children with esophageal atresia in Sweden and Germany, using a patient-derived development approach consistent with international guidelines. Following a literature review, standardized focus groups were conducted with 30 Swedish families of children with esophageal atresia aged 2-17 years. The results were used for item generation of two age-specific pilot questionnaire versions. These were then translated from Swedish into German with considerations of linguistic and semantical perspectives. The 30-item pilot questionnaire for children aged 2-7 years was completed by 34 families (parent report), and the 50-item pilot questionnaire for children aged 8-17 years was completed by 52 families (51 child report, 52 parent report), with an overall response rate of 96% in the total sample. Based on predefined psychometric criteria, poorly performing items were removed, resulting in an 18-item version with three domains (Eating, Physical health and treatment, Social isolation and stress,) for children aged 2-7 years and a 26-item version with four domains (Eating, Social relationships, Body perception, and Health and well-being) for children aged 8-17 years. Both versions demonstrated good internal consistency reliability and acceptable convergent and known-groups validity for the total scores. The study identified specific health-related quality-of-life domains for pediatric patients with esophageal atresia, highlighting issues that are important for follow-up care. After field testing in a larger patient sample, this instrument can be used to enhance the evaluation of pediatric surgical care.

Epistatic interaction of genetic depression risk variants in the human subgenual cingulate cortex during memory encoding

Recent genome-wide association studies have pointed to single-nucleotide polymorphisms (SNPs) in genes encoding the neuronal calcium channel CaV1.2 (CACNA1C; rs1006737) and the presynaptic active zone protein Piccolo (PCLO; rs2522833) as risk factors for affective disorders, particularly major depression. Previous neuroimaging studies of depression-related endophenotypes have highlighted the role of the subgenual cingulate cortex (CG25) in negative mood and depressive psychopathology. Here, we aimed to assess how recently associated PCLO and CACNA1C depression risk alleles jointly affect memory-related CG25 activity as an intermediate phenotype in clinically healthy humans. To investigate the combined effects of rs1006737 and rs2522833 on the CG25 response, we conducted three functional magnetic resonance imaging studies of episodic memory formation in three independent cohorts (N=79, 300, 113). An epistatic interaction of PCLO and CACNA1C risk alleles in CG25 during memory encoding was observed in all groups, with carriers of no risk allele and of both risk alleles showing higher CG25 activation during encoding when compared with carriers of only one risk allele. Moreover, PCLO risk allele carriers showed lower memory performance and reduced encoding-related hippocampal activation. In summary, our results point to region-specific epistatic effects of PCLO and CACNA1C risk variants in CG25, potentially related to episodic memory. Our data further suggest that genetic risk factors on the SNP level do not necessarily have additive effects but may show complex interactions. Such epistatic interactions might contribute to the 'missing heritability' of complex phenotypes.

Mouse model of desmin-related cardiomyopathy

BACKGROUND

The consequence of upregulation of desmin in the heart is unknown. Mutations in desmin have been linked to desmin-related myopathy (DRM), which is characterized by abnormal intrasarcoplasmic accumulation of desmin, but direct causative evidence that a desmin mutation leads to aberrant intrasarcoplasmic desmin accumulation, aggregation, and cardiomyopathy is lacking.

METHODS AND RESULTS

Multiple transgenic mouse lines that expressed either murine wild-type desmin or a 7-amino acid deletion (R173 through E179) desmin (D7-des) mutation linked to DRM were made. The distribution of desmin protein was unchanged, and no overt phenotype was detected in the wild-type desmin transgenic mice. In contrast, the D7-des mouse heart showed aberrant intrasarcoplasmic and electron-dense granular filamentous aggregates that were desmin-positive and characteristic of human DRM. The desmin filament network was significantly disrupted, and myofibril alignment was visibly compromised. Although systolic function at the whole-organ level was substantially conserved in the young adult animals, the ability of the heart to respond to beta-agonist stimulation, as measured in the intact animal, was significantly blunted.

CONCLUSIONS

Upregulation of desmin protein at moderate levels is not detrimental. However, the D7-des mutation is dominant negative, and expression of the mutant protein leads to the appearance of aggregates that are characteristic of and diagnostic for human desmin-related cardiomyopathy.

Musical backgrounds, listening habits, and aesthetic enjoyment of adult cochlear implant recipients

This paper describes the listening habits and musical enjoyment of postlingually deafened adults who use cochlear implants. Sixty-five implant recipients (35 females, 30 males) participated in a survey containing questions about musical background, prior involvement in music, and audiologic success with the implant in various listening circumstances. Responses were correlated with measures of cognition and speech recognition. Sixty-seven implant recipients completed daily diaries (7 consecutive days) in which they reported hours spent in specific music activities. Results indicate a wide range of success with music. In general, people enjoy music less postimplantation than prior to hearing loss. Musical enjoyment is influenced by the listening environment (e.g., a quiet room) and features of the music.

Conserved arginine-516 of Penicillium amagasakiense glucose oxidase is essential for the efficient binding of beta-D-glucose

The effects of mutation of key conserved active-site residues (Tyr-73, Phe-418, Trp-430, Arg-516, Asn-518, His-520 and His-563) of glucose oxidase from Penicillium amagasakiense on substrate binding were investigated. Kinetic studies on the oxidation of beta-D-glucose combined with molecular modelling showed the side chain of Arg-516, which forms two hydrogen bonds with the 3-OH group of beta-D-glucose, to be absolutely essential for the efficient binding of beta-D-glucose. The R516K variant, whose side chain forms only one hydrogen bond with the 3-OH group of beta-D-glucose, exhibits an 80-fold higher apparent K(m) (513 mM) but a V(max) only 70% lower (280 units/mg) than the wild type. The complete elimination of a hydrogen-bond interaction between residue 516 and the 3-OH group of beta-D-glucose through the substitution R516Q effected a 120-fold increase in the apparent K(m) for glucose (to 733 mM) and a decrease in the V(max) to 1/30 (33 units/mg). None of the other substitutions, with the exception of variant F418A, affected the apparent K(m) more than 6-fold. In contrast, the removal of aromatic or bulky residues at positions 73, 418 or 430 resulted in decreases in the maximum rates of glucose oxidation to less than 1/90. Variants of the potentially catalytically active His-520 and His-563 were completely, or almost completely, inactive. Thus, of the residues forming the active site of glucose oxidase, Arg-516 is the most critical amino acid for the efficient binding of beta-D-glucose by the enzyme, whereas aromatic residues at positions 73, 418 and 430 are important for the correct orientation and maximal velocity of glucose oxidation.

Distant downstream sequence determinants can control N-tail translocation during protein insertion into the endoplasmic reticulum membrane

We have studied the membrane insertion of ProW, an Escherichia coli inner membrane protein with seven transmembrane segments and a large periplasmic N-terminal tail, into endoplasmic reticulum (ER)-derived dog pancreas microsomes. Strikingly, significant levels of N-tail translocation is seen only when a minimum of four of the transmembrane segments are present; for constructs with fewer transmembrane segments, the N-tail remains mostly nontranslocated and the majority of the molecules adopt an "inverted" topology where normally nontranslocated parts are translocated and vice versa. N-tail translocation can also be promoted by shortening of the N-tail and by the addition of positively charged residues immediately downstream of the first trasnmembrane segment. We conclude that as many as four consecutive transmembrane segments may be collectively involved in determining membrane protein topology in the ER and that the effects of downstream sequence determinants may vary depending on the size and charge of the N-tail. We also provide evidence to suggest that the ProW N-tail is translocated across the ER membrane in a C-to-N-terminal direction.

1.8 and 1.9 A resolution structures of the Penicillium amagasakiense and Aspergillus niger glucose oxidases as a basis for modelling substrate complexes

Glucose oxidase is a flavin-dependent enzyme which catalyses the oxidation of beta-D-glucose by molecular oxygen to delta-gluconolactone and hydrogen peroxide. The structure of the enzyme from Aspergillus niger, previously refined at 2.3 A resolution, has been refined at 1.9 A resolution to an R value of 19.0%, and the structure of the enzyme from Penicillium amagasakiense, which has 65% sequence identity, has been determined by molecular replacement and refined at 1.8 A resolution to an R value of 16.4%. The structures of the partially deglycosylated enzymes have an r.m.s. deviation of 0.7 A for main-chain atoms and show four N-glycosylation sites, with an extended carbohydrate moiety at Asn89. Substrate complexes of the enzyme from A. niger were modelled by force-field methods. The resulting model is consistent with results from site-directed mutagenesis experiments and shows the beta-D-glucose molecule in the active site of glucose oxidase, stabilized by 12 hydrogen bonds and by hydrophobic contacts to three neighbouring aromatic residues and to flavin adenine dinucleotide. Other hexoses, such as alpha-D-glucose, mannose and galactose, which are poor substrates for the enzyme, and 2-deoxy-D-glucose, form either fewer bonds or unfavourable contacts with neighbouring amino acids. Simulation of the complex between the reduced enzyme and the product, delta-gluconolactone, has provided an explanation for the lack of product inhibition by the lactone.

Transgenic over-expression of a motor protein at high levels results in severe cardiac pathology

Transgenesis has become a useful tool in effecting a complete or partial remodeling of the cardiac contractile apparatus. Although gene dosage effects were initially a concern, recent data showed that the heart is able to accommodate varying levels of transgenic over-expression without detectable ill effects. The present study was designed to test the limits of the transgenic paradigm in terms of the production of a cardiac phenotype due simply to the over-expression of a contractile protein. To this end, eight lines of mice which express an isoform of the essential myosin light chain 1 that is normally found in the adult ventricle (ELC1v) were generated. Overt phenotype was correlated both with the level of expression/protein replacement and copy number of the transgene. Two of the lines showed essentially complete replacement of the atrial isoform (ELC1a) with ELC1v. However, the phenotypes of the two lines differed dramatically. The line with the lower copy number (37 copies), and moderate over-expression (16 fold) showed no overt pathology while a line with very high copy number (94 copies) and extremely high levels of over-expression (27-50 fold) developed a significant atrial hypertrophy, dilation and cardiomyopathy. These data indicate that very high expression levels of a contractile protein can cause a cardiac pathology that is unrelated to its degree of replacement in the sarcomere and the unique role(s) it may assume in motor protein function.

The molecular basis for therapeutic concepts utilizing CD14

The CD14 molecule is a key receptor on myeloid lineage cells involved in the recognition of lipopolysaccharide (LPS) and Gram-negative bacteria. The application of its soluble form, sCD14, has been shown to protect mice from lethality in LPS-induced shock. Therefore the protein or its derivatives may be considered as a possible therapeutic alternative for the treatment of patients suffering from Gram-negative septic shock. In this study we performed an alanine scan of amino acids 1 to 152 of human CD14. Twenty-three substitution mutants were generated and stably transfected into CHO-cells. In each mutant five amino acids were substituted by alanine. We analyzed (a) whether mutant proteins expressed on the surface of transfectants were recognized by a panel of anti-CD14 monoclonal antibodies (mAb's), (b) the ability of mCD14-mutants to bind LPS and E. coli in a serum- or LBP-dependent manner, and (c) the capacity of soluble mutants to mediate the LPS-induced IL 6 release of U 373 astrocytoma cells. Twenty-one CD14-mutants were expressed on the surface of transfectants and 18 were present as soluble forms in the culture supernatants. We demonstrated that only CD14(39-41,43-44)A completely lacked the ability to bind LPS and E. coli. In addition, a combined mutant CD14(9-13/57,59,61-63)A had very limited capacity to interact with LPS indicating that the LPS-binding site of human CD14 is a conformational epitope. Analysis of LPS-induced activation of CD14-negative U 373 cells revealed that the regions 9-13 and 91-101 are most important for sCD14-mediated signalling.

Structural and kinetic properties of nonglycosylated recombinant Penicillium amagasakiense glucose oxidase expressed in Escherichia coli

The gene coding for Penicillium amagasakiense glucose oxidase (GOX; beta-D-glucose; oxygen 1-oxidoreductase [EC 1.1.3.4]) has been cloned by PCR amplification with genomic DNA as template with oligonucleotide probes derived from amino acid sequences of N- and C-terminal peptide fragments of the enzyme. Recombinant Escherichia coli expression plasmids have been constructed from the heat-induced pCYTEXP1 expression vector containing the mature GOX coding sequence. When transformed into E. coli TG2, the plasmid directed the synthesis of 0.25 mg of protein in insoluble inclusion bodies per ml of E. coli culture containing more than 60% inactive GOX. Enzyme activity was reconstituted by treatment with 8 M urea and 30 mM dithiothreitol and subsequent 100-fold dilution to a final protein concentration of 0.05 to 0.1 mg ml-1 in a buffer containing reduced glutathione-oxidized glutathione, flavin adenine dinucleotide, and glycerol. Reactivation followed first-order kinetics and was optimal at 10 degrees C. The reactivated recombinant GOX was purified to homogeneity by mild acidification and anion-exchange chromatography. Up to 12 mg of active GOX could be purified from a 1-liter E. coli culture. Circular dichroism demonstrated similar conformations for recombinant and native P. amagasakiense GOXs. The purified enzyme has a specific activity of 968 U mg-1 and exhibits kinetics of glucose oxidation similar to those of, but lower pH and thermal stabilities than, native GOX from P. amagasakiense. In contrast to the native enzyme, recombinant GOX is nonglycosylated and contains a single isoform of pI 4.5. This is the first reported expression of a fully active, nonglycosylated form of a eukaryotic, glycosylated GOX in E. coli.

Different efficacy of soluble CD14 treatment in high- and low-dose LPS models

BACKGROUND

About 50% of septic shock cases are attributed to Gram-negative bacteria or their cell wall compound lipopolysaccharide (LPS, endotoxin). An attractive therapeutic strategy could target the binding of LPS to its cellular receptors. In vitro the soluble form of the endotoxin receptor CD14 (sCD14) competitively prevents binding of LPS to membrane-bound CD14 and inhibits LPS-stimulated macrophage responses.

METHODS

We tested the in vivo endotoxin-neutralizing capacity of human recombinant sCD14 using a mouse model of shock induced by 8 micrograms g-1 of LPS from Salmonella abortus equi.

RESULTS

In this model, treatment with sCD14 reduced mortality if administered before or simultaneously with LPS. However, application of sCD14 had no effect on the secretion of early proinflammatory cytokines and did not protect the animals against the development of apparent shock symptoms and liver injury. sCD14 also failed to prevent LPS-inducible (7.5 ng g-1) liver injury in galactosamine-sensitized mice.

CONCLUSION

In line with these findings, sCD14 did not block LPS-induced activation of Kupffer cells in vitro, which might explain why the compound only partially protected in vivo.

Timbral recognition and appraisal by adult cochlear implant users and normal-hearing adults

The purpose of this study was to examine the appraisal and recognition of timbre (four different musical instruments) by recipients of Clarion cochlear implants (CIS strategy, 75- or 150-microsec pulse widths) and to compare their performance with that of normal-hearing listeners. Twenty-eight Clarion cochlear implant users and 41 normal-hearing listeners were asked to give a subjective assessment of the pleasantness of each instrument using a visual analog scale with anchors of "like very much" to "dislike very much," and to match each sound with a picture of the instrument they believed had produced it. No significant differences were found between the two different pulse widths for either appreciation or recognition; thus, data from the two pulse widths following 12 months of Clarion implant use were collapsed for further analyses. Significant differences in appraisal were found between normal-hearing listeners and implant recipients for two of the four instruments sampled. Normal-hearing adults were able to recognize all of the instruments with significantly greater accuracy than implant recipients. Performance on timbre perception tasks was correlated with speech perception and cognitive tasks.