Treatment sequences and drug costs from diagnosis to death in multiple myeloma

Novel therapies for multiple myeloma (MM) have improved patient survival, but their high costs strain healthcare budgets. End-of-life phases of treatment are generally the most expensive, however, these high costs may be less justifiable in the context of a less pronounced clinical benefit. To manage drug expenses effectively, detailed information on end-of-life drug administration and costs are crucial. In this retrospective study, we analysed treatment sequences and drug costs from 96 MM patients in the Netherlands who died between January 2017 and July 2019. Patients received up to 16 lines of therapy (median overall survival: 56.5 months), with average lifetime costs of €209 871 (€3111/month; range: €3942-€776 185) for anti-MM drugs. About 85% of patients received anti-MM treatment in the last 3 months before death, incurring costs of €20 761 (range: €70-€50 122; 10% of total). Half of the patients received anti-MM treatment in the last 14 days, mainly fully oral regimens (66%). End-of-life treatment costs are substantial despite limited survival benefits. The use of expensive treatment options is expected to increase costs further. These data serve as a reference point for future cost studies, and further research is needed to identify factors predicting the efficacy and clinical benefit of continuing end-of-life therapy.

<i>Corrigendum to</i>: Molecular relationships of the red-bellied dasyure (<i>Phascolosorex doriae</i>) &#x2013; a rare marsupial from western New Guinea

The mitochondrial genome of the rare endemic New Guinean dasyurid <italic>Phascolosorex doriae</italic> (<xref ref-type="bibr" rid="R11">Thomas 1886</xref>) has been used to clarify relationships within &#x2018;phascolosoricinae&#x2019;. The mitochondrial genome has the typical gene arrangement seen in other marsupials. Molecular analyses using complete mitogenomes of other dasyurids resolve the red-bellied dasyure as sister to the narrow-striped dasyure <italic>Phascolosorex dorsalis</italic> and show that these two species diverged in the early Pliocene. The invasion of emergent New Guinean rainforest habitats (in the late Miocene) by the common ancestor of <italic>Ph. doriae</italic>, <italic>Ph. dorsalis</italic> and <italic>Neophascogale lorentzii</italic> represents one of three separate such invasions by dasyurid lineages.

Molecular relationships of the red-bellied dasyure (Phascolosorex doriae) – a rare marsupial from western New Guinea

The mitochondrial genome of the rare endemic New Guinean dasyurid Phascolosorex doriae (Thomas 1886) has been used to clarify relationships within ‘phascolosoricinae’. The mitochondrial genome has the typical gene arrangement seen in other marsupials. Molecular analyses using complete mitogenomes of other dasyurids resolve the red-bellied dasyure as sister to the narrow-striped dasyure Phascolosorex dorsalis and show that these two species diverged in the early Pliocene. The invasion of emergent New Guinean rainforest habitats (in the late Miocene) by the common ancestor of Ph. doriae, Ph. dorsalis and Neophascogale lorentzii represents one of three separate such invasions by dasyurid lineages.

Reasons for not reaching or using web-based self-management applications, and the use and evaluation of Oncokompas among cancer survivors, in the context of a randomised controlled trial

INTRODUCTION

The web-based self-management application Oncokompas was developed to support cancer survivors to monitor health-related quality of life and symptoms (Measure) and to provide tailored information (Learn) and supportive care options (Act). In a previously reported randomised controlled trial (RCT), 68% of 655 recruited survivors were eligible, and of those 45% participated in the RCT. Among participants of the RCT that were randomised to the intervention group, 52% used Oncokompas as intended. The aim of this study was to explore reasons for not participating in the RCT, and reasons for not using Oncokompas among non-users, and the use and evaluation of Oncokompas among users.

METHODS

Reasons for not participating were assessed with a study-specific questionnaire among 243 survivors who declined participation. Usage was investigated among 320 participants randomised to the intervention group of the RCT via system data and a study-specific questionnaire that was assessed during the 1 week follow-up (T1) assessment.

RESULTS

Main reasons for not participating were not interested in participation in scientific research (40%) and not interested in scientific research and Oncokompas (28%). Main reasons for not being interested in Oncokompas were wanting to leave the period of being ill behind (29%), no symptom burden (23%), or lacking internet skills (18%). Out of the 320 participants in the intervention group 167 (52%) used Oncokompas as intended. Among 72 non-users, main reasons for not using Oncokompas were no symptom burden (32%) or lack of time (26%). Among 248 survivors that activated their account, satisfaction and user-friendliness were rated with a 7 (scale 0-10). Within 3 (IQR 1-4) sessions, users selected 32 (IQR 6-37) topics. Main reasons for not using healthcare options in Act were that the information in Learn was already sufficient (44%) or no supportive care needs (32%).

DISCUSSION

Main reasons for not reaching or using Oncokompas were no symptom burden, no supportive care needs, or lack of time. Users selected many cancer-generic and tumour-specific topics to address, indicating added value of the wide range of available topics.

The eHealth self-management application 'Oncokompas' that supports cancer survivors to improve health-related quality of life and reduce symptoms: which groups benefit most?

BACKGROUND

Oncokompas is a web-based self-management application that supports cancer survivors to monitor their health-related quality of life (HRQOL) and symptoms, and to obtain personalised feedback and tailored options for supportive care. In a large randomised controlled trial among survivors of head and neck cancer, colorectal cancer, and breast cancer and (non-)Hodgkin lymphoma, Oncokompas proved to improve HRQOL, and to reduce several tumour-specific symptoms. Effect sizes were however small, and no effect was observed on the primary outcome patient activation. Therefore, this study aims to explore which subgroups of cancer survivors may especially benefit from Oncokompas.

MATERIALS AND METHODS

Cancer survivors (n = 625) were randomly assigned to the intervention group (access to Oncokompas, n = 320) or control group (6 months waiting list, n = 305). Outcome measures were HRQOL, tumour-specific symptoms, and patient activation. Potential moderators included socio-demographic (sex, age, marital status, education, employment), clinical (tumour type, stage, time since diagnosis, treatment modality, comorbidities), and personal factors (self-efficacy, personal control, health literacy, Internet use), and patient activation, mental adjustment to cancer, HRQOL, symptoms, and need for supportive care, measured at baseline. Linear mixed models were performed to investigate potential moderators.

RESULTS

The intervention effect on HRQOL was the largest among cancer survivors with low to moderate self-efficacy, and among those with high personal control and those with high health literacy scores. Cancer survivors with higher baseline symptom scores benefitted more on head and neck (pain in the mouth, social eating, swallowing, coughing, trismus), and colorectal cancer (weight) specific symptoms.

DISCUSSION

Oncokompas seems most effective in reducing symptoms in head and neck cancer and colorectal cancer survivors who report a higher burden of tumour-specific symptoms. Oncokompas seems most effective in improving HRQOL in cancer survivors with lower self-efficacy, and in cancer survivors with higher personal control, and higher health literacy.

Cost-utility of an eHealth application 'Oncokompas' that supports cancer survivors in self-management: results of a randomised controlled trial

Purpose

The eHealth self-management application ‘Oncokompas’ was developed to support cancer survivors in monitoring health-related quality of life (HRQOL) and symptoms, and obtaining personalized feedback and options for supportive care. The aim of this study was to assess the cost-utility of Oncokompas compared with care as usual (CAU) among cancer survivors.

Methods

Survivors were randomly allocated to the intervention or control group. Direct (non-)medical, indirect non-medical costs, and HRQOL were measured at 3- and 6-month follow-up, using iMTA Medical Consumption and Productivity Costs and the EuroQol-5D questionnaires. Mean cumulative costs and quality-adjusted life-years (QALYs) were compared between both groups.

Results

In total, 625 survivors were randomized into intervention (n = 320) or control group (n = 305). Base case analysis showed that incremental costs from a societal perspective were − €163 (95% CI, − 665 to 326), and incremental QALYs were 0.0017 (95% CI, − 0.0121 to 0.0155) in the intervention group compared with those in the control group. The probability that, compared with CAU, Oncokompas is more effective was 60%, less costly 73%, and both more effective and less costly 47%. Sensitivity analyses showed that incremental costs vary between − €40 and €69, and incremental QALYs vary between − 0.0023 and − 0.0057.

Conclusion

Oncokompas is likely to be equally effective on utilities, and not more expensive than CAU, and will therefore contribute to sustainable cancer survivorship care in a (cost-)effective manner.

Implications for Cancer Survivors

Oncokompas seems to improve HRQOL and reduces the burden of several tumour-specific symptoms, while costs from a societal perspective are similar to CAU.

Electronic supplementary material

The online version of this article (10.1007/s11764-020-00912-9) contains supplementary material, which is available to authorized users.

Species relationships in the dasyurid marsupial genus Pseudantechinus (Marsupialia : Dasyuridae): a re-examination of the taxonomic status of Pseudantechinus roryi

The status of Pseudantechinus roryi relative to its congeners has been determined from DNA sequences obtained from both nuclear and mitochondrial gene loci. Although all other recognised species of Pseudantechinus form reciprocally monophyletic lineages in phylogenetic analyses, individuals identified in museum collections as Ps. roryi (including type specimens) were indistinguishable from those identified as Ps. macdonnellensis. Ps. roryi is thus considered to be a synonym of Ps. macdonnellensis. Neighbour-joining network analyses failed to reveal any clear biogeographic differences between populations of Ps. macdonnellensis other than some evidence of isolation by distance.

Quality specifications in postgraduate medical e-learning: an integrative literature review leading to a postgraduate medical e-learning model

BACKGROUND

E-learning is driving major shifts in medical education. Prioritizing learning theories and quality models improves the success of e-learning programs. Although many e-learning quality standards are available, few are focused on postgraduate medical education.

METHODS

We conducted an integrative review of the current postgraduate medical e-learning literature to identify quality specifications. The literature was thematically organized into a working model.

RESULTS

Unique quality specifications (n = 72) were consolidated and re-organized into a six-domain model that we called the Postgraduate Medical E-learning Model (Postgraduate ME Model). This model was partially based on the ISO-19796 standard, and drew on cognitive load multimedia principles. The domains of the model are preparation, software design and system specifications, communication, content, assessment, and maintenance.

CONCLUSION

This review clarified the current state of postgraduate medical e-learning standards and specifications. It also synthesized these specifications into a single working model. To validate our findings, the next-steps include testing the Postgraduate ME Model in controlled e-learning settings.

Comment on a research note reporting new populations of the northern quoll in Western Australia

The recent report by Turpin and Bamford (2015) notes a range extension for northern quolls in the Pilbara Bioregion of Western Australia. Mitochondrial DNA sequences derived from five scats show that the new individuals nest within a clade containing all other Pilbara animals. Northern quolls from the Pilbara Bioregion are genetically distinct from congeners from the Kimberley Bioregion. We note that there is no evidence for maternal gene flow between these two regions.

Urinary neutrophil gelatinase-associated lipocalin to hepcidin ratio as a biomarker of acute kidney injury in intensive care unit patients

BACKGROUND

Labile iron is important in the pathogenesis of acute kidney injury (AKI). Neutrophil gelatinase-associated lipocalin (NGAL) and hepcidin control iron metabolism and are upregulated during renal stress. However, higher levels of urinary NGAL are associated with AKI severity whereas higher urinary hepcidin levels are associated with absence of AKI. We aimed to investigate the value of combining both biomarkers to estimate the severity and progression of AKI in intensive care unit (ICU) patients.

METHODS

Urinary NGAL and hepcidin were quantified within 48 hours of ICU admission in patients with the systemic inflammatory response syndrome and early kidney dysfunction (oliguria for ≥ 2 hours and/or a 25 µmol/L creatinine rise from baseline). Diagnostic and prognostic characteristics were assessed by logistic regression and receiver operating characteristics (ROC) analysis.

RESULTS

Of 102 patients, 26 had mild AKI and 28 patients had severe AKI on admission. Sepsis (21%), cardiac surgery (17%) and liver failure (9%) were primary admission diagnoses. NGAL increased (P=0.03) whereas hepcidin decreased (P=0.01) with increasing AKI severity. The value of NGAL/hepcidin ratio to detect severe AKI was higher than when NGAL and hepcidin were used individually and persisted after adjusting for potential confounders (adjusted OR 2.40, 95% CI 1.20-4.78). The ROC areas for predicting worsening AKI were 0.50, 0.52 and 0.48 for NGAL, 1/hepcidin and the NGAL/hepcidin ratio.

CONCLUSION

The NGAL/hepcidin ratio is more strongly associated with severe AKI than the single biomarkers alone. NGAL and hepcidin, alone or combined as a ratio, were unable to predict progressive AKI in this selected ICU cohort.

Influenza vaccination coverage in patients treated with chemotherapy: current clinical practice

BACKGROUND

Influenza virus vaccination is recommended for patients treated with chemotherapy. Little is known about vaccination coverage in these patients.

METHODS

Vaccination coverage in the Netherlands was analysed by questionnaires completed by general practitioners, within a catchment area of 1.3 million people, in the period 2010-2011.

RESULTS

Of 433 eligible adult patients treated with chemotherapy for breast or colorectal cancer, 144 patients gave permission for us to approach their general practitioner with a questionnaire. General practitioners were asked about vaccination coverage, awareness of recommendations and their opinion about the responsibility for vaccination. We received 114 (79%) completed questionnaires. Sixty-seven out of 114 patients (59%) were vaccinated against influenza. Forty-four (66%) of these patients also had an indication for vaccination based on age (age ≥60 years). According to 48% of the general practitioners, the responsibility for vaccination belongs to the competence of the treating medical oncologist.

CONCLUSION

Influenza vaccination coverage is limited to 59% of patients treated with chemotherapy. Guidelines for responsibility (general practitioner or medical oncologist) may increase the vaccination rate of cancer patients.

Unresectable pancreatic tumour? The issue is tissue

The majority of tumours in the pancreas are adenocarcinomas for which therapeutic options are limited and which are associated with an unsatisfactory prognosis. However, alternative diagnoses may result in other therapeutic approaches with often a more favourable outcome. Hence, it is crucial to obtain a histological diagnosis before a definitive therapeutic plan can be devised. In this manuscript, a small series of pancreatic tumours other than adenocarcinoma are described.

Past and present distribution of Dasycercus: toward a better understanding of the identity of specimens in cave deposits and the conservation status of the currently recognised species D. blythi and D. cristicauda (Marsupialia : Dasyuridae)

Maps of the distribution of the two currently recognised species of Dasycercus, D. blythi and D. cristicauda have been prepared following correct identification based on tail morphology of specimens in the modern collections of all Australian museums. Localities in which the remains of Dasycercus have been found in cave deposits have also been mapped and an attempt made to determine the specific identity of some of these specimens. Following examination of larger samples of each species, differences in the premolar dentition were found to no longer be diagnostic. Most cave specimens could not be assigned to species on the basis of some dental measurements. DNA sequences could provide a means for establishing the identity of the cave specimens. Correct identification of specimens, together with knowledge of the search effort underlying the known distribution and persistence of the species in localities over their ranges, is essential for assessment of their conservation status.

Increased serum hepcidin levels in patients with porphyria cutanea tarda

BACKGROUND

Increased iron stores- are common in porphyria cutanea tarda (PCT) patients, but the pathophysiological pathways remain unknown. Down-regulation of hepcidin, a peptide which regulates systemic iron homeostasis, has been demonstrated in different conditions associated with PCT, such as haemochromatosis, chronic hepatitis C (CHC) and excessive alcohol intake. However, serum hepcidin levels have not yet been studied in PCT patients.

OBJECTIVE

To measure the serum hepcidin levels in patients with PCT, CHC and control patients, and to assess the association of hepcidin with serum markers of inflammation, iron overload and oxidative stress.

METHODS

Hepcidin levels were measured by a competitive enzyme-linked immunosorbent assay in serum samples of patients presenting PCT (n = 30), CHC (n = 31) and healthy volunteers (n = 52).

RESULTS

The mean of serum hepcidin levels was significantly higher in the PCT group (129.6 ng/mL) in comparison with the mean values in the CHC (41.3 ng/mL) and control (70.8 ng/mL) groups. The serum concentration of ferritin and interleukin-6 (IL-6) was also significantly higher in the PCT group, and correlated strongly with the hepcidin levels. The PCT patients with hepatitis C virus (HCV) infection showed significantly higher hepcidin levels than the group of CHC patients without porphyria.

CONCLUSION

Serum hepcidin levels are increased in patients with PCT suggesting that the mechanisms regulating iron homeostasis in PCT differ from those involved in other related disorders, such as haemochromatosis, HCV infection or alcohol abuse.

Molecular relationships of species of Pseudantechinus, Parantechinus and Dasykaluta (Marsupialia: Dasyuridae)

The eight currently recognized species of false antechinuses are members of the dasyurid marsupial genera Pseudantechinus, Parantechinus and Dasykaluta. Previous morphological and molecular studies have confidently placed these species in the tribe Dasyurini, but their affinities within that clade are poorly understood. We report phylogenetic analyses of cytochrome b, 12S rRNA, 16S rRNA, IRBP, �-fibrinogen intron 7 and e-globin intron 1 DNA sequences from one or more exemplars of each species of false antechinus and selected outgroups. The three genera of false antechinuses do not form a monophyletic group, but more specific relationships among them remain unresolved. Branching order within Pseudantechinus is reasonably clear: Ps. bilarni is sister to the other species, among which Ps. woolleyae, Ps. ningbing and Ps. mimulus form successive branches above the root. Our results support the current generic affiliation of Ps. bilarni, in agreement with previous morphological and allozyme studies, though this support is not strong. Our data fail to demonstrate reciprocal monophyly of Ps. macdonnellensis and Ps. roryi haplotypes, suggesting instead that populations within this group have a complex phylogeographic structure that will only be elucidated with more detailed field sampling.

Characterization of two whey protein genes in the Australian dasyurid marsupial, the stripe-faced dunnart (Sminthopsis macroura)

We report the first isolation and sequencing of genomic BAC clones containing the marsupial milk protein genes Whey Acidic Protein (WAP) and Early Lactation Protein (ELP). The stripe-faced dunnart WAPgene sequence contained five exons, the middle three of which code for the WAPmotifs and four disulphide core domains which characterize WAP. The dunnart ELPgene sequence contained three exons encoding a protein with a Kunitz motif common to serine protease inhibitors. Fluorescence in situ hybridization located the WAPgene to chromosome 1p in the stripe-faced dunnart, and the ELPgene to 2q. Northern blot analysis of lactating mammary tissue of the closely related fat-tailed dunnart has shown asynchronous expression of these milk protein genes. ELPwas expressed at only the earlier phase of lactation and WAPonly at the later phase of lactation, in contrast to beta-lactoglobulin (BLG) and alpha-lactalbumin (ALA) genes, which were expressed in both phases of lactation. This asynchronous expression during the lactation cycle in the fat-tailed dunnart is similar to other marsupials and it probably represents a pattern that is ancestral to Australian marsupials.

Phase I and pharmacokinetic study of the novel chemoprotector BNP7787 in combination with cisplatin and attempt to eliminate the hydration schedule

BNP7787 (disodium 2,2′-dithio-bis-ethane sulphonate; Tavocept™) is a novel agent developed to protect against cisplatin (cis-diammine-dichloroplatinum(II))-associated chronic toxicities. In this study, we determined the recommended dose of BNP7787 when preceding a fixed dose of cisplatin, the pharmacokinetics (PKs) and the possible reduction of saline hydration. Patients with advanced solid tumours received BNP7787 in escalating doses of 4.1–41 g m⁻² as a 15-min intravenous (i.v.) infusion followed by cisplatin 75 mg m⁻² as a 60-min i.v. infusion together with pre- and postcisplatin saline hydration in a volume of 2200 ml; cycles were repeated every 3 weeks. PK was carried out using BNP7787, cisplatin and the combination. Twenty-five patients were enrolled in stage I of the study to determine the recommended dose of BNP7787. No dose-limiting toxicity was reached. The highest dose level of 41 g m⁻² resulted in a low incidence of grade 2 toxicities, being nausea and vomiting, dry mouth or bad taste and i.v. injection site discomfort. Doses of BNP7787 ⩾18.4 g m⁻² did not show a drug interaction between BNP7787 and cisplatin. In stage II of the study, patients received a fixed dose of BNP7787 of 18.4 g m⁻² preceding cisplatin and were entered in prespecified reduced saline hydration steps. A total of 21 patients in cohorts of six to nine patients received reduced saline hydration of 1600 ml (step A), 1000 ml (step B) and 500 ml (step C). In step C, two out of six evaluable patients experienced grade 1 nephrotoxicity. Cisplatin acute toxicities in all 46 patients were as expected. Only five patients complained of paresthesias grade 1 and six developed slight audiometric changes. Partial tumour response was observed in four patients and stable disease in 15 patients. In conclusion, BNP7787 was tolerated well up to doses of 41 g m⁻². The recommended dose of 18.4 g m⁻² enabled safe reduction of the saline hydration schedule for cisplatin to 1000 ml. Further studies will assess whether BNP7787 offers protection against platinum-related late side effects.

Sequencing and mapping hemoglobin gene clusters in the Australian model dasyurid marsupial Sminthopsis macroura

Comparing globin genes and their flanking sequences across many species has allowed globin gene evolution to be reconstructed in great detail. Marsupial globin sequences have proved to be of exceptional significance. A previous finding of a beta(beta)-like omega(omega) gene in the alpha(alpha) cluster in the tammar wallaby suggested that the alpha and beta cluster evolved via genome duplication and loss rather than tandem duplication. To confirm and extend this important finding we isolated and sequenced BACs containing the alpha and beta loci from the distantly related Australian marsupial Sminthopsis macroura. We report that the alpha gene lies in the same BAC as the beta-like omega gene, implying that the alpha-omega juxtaposition is likely to be conserved in all marsupials. The LUC7L gene was found 3' of the S. macroura alpha locus, a gene order shared with humans but not mouse, chicken or fugu. Sequencing a BAC contig that contained the S. macroura beta globin and epsilon globin loci showed that the globin cluster is flanked by olfactory genes, demonstrating a gene arrangement conserved for over 180 MY. Analysis of the region 5' to the S. macroura epsilon (epsilon) globin gene revealed a region similar to the eutherian LCR, containing sequences and potential transcription factor binding sites with homology to eutherian hypersensitive sites 1 to 5. FISH mapping of BACs containing S. macroura alpha and beta globin genes located the beta globin cluster on chromosome 3q and the alpha locus close to the centromere on 1q, resolving contradictory map locations obtained by previous radioactive in situ hybridization.

Molecular phylogenetic relationships of two extinct potoroid marsupials, Potorous platyops and Caloprymnus campestris (Potoroinae: Marsupialia)

Complete 12S rRNA and partial cytochrome b (cytb) gene sequences have been obtained from museum samples of two recently extinct potoroids-Potorous platyops and Caloprymnus campestris. Phylogenetic analyses based on these mitochondrial DNA sequences suggest that the broad-faced potoroo (P. platyops) was a close relative of the recently discovered Potorous longipes and the recently re-discovered Potorous gilberti. Although the extinct desert rat-kangaroo (C. campestris) was clearly resolved as a member of the subfamily Potoroinae, its precise relationships vis a vis other living potoroines are unclear. We confirmed that the rufous rat-kangaroo (Aepyprymnus rufescens) is sister to all living Bettongia species, but the molecular data provide no support for a sister relationship between A. rufescens and C. campestris as suggested by on the basis of four shared morphological characters. Molecular dating analyses suggest that the initial radiation of potoroinae seems to have occurred soon after its origin in the early Miocene. Within Potoroinae, C. campestris diverged from other taxa approximately 16 million years ago. P. platyops diverged from P. longipes+P. gilberti approximately 14-15 million years ago.

Chromosomal painting detects non-random chromosome arrangement in dasyurid marsupial sperm

Chromosome arrangements have been studied in metaphase and interphase somatic cells and in sperm of many animal species, but there are conflicting data and it is still not clear whether chromosomes are arranged randomly or non-randomly. We used chromosome painting to reveal the positions of chromosomes in marsupial sperm. Marsupials are ideally suited for these studies because they have only a few large chromosomes. Here, we show that chromosomes occupy fixed positions in the immature and mature sperm of Sminthopsis crassicaudata. We suggest that the non-random arrangement of chromosomes in marsupial sperm may be important in establishing chromosome arrangement and patterns of gene activity within the developing embryo.

Beta-amyloid activates the mitogen-activated protein kinase cascade via hippocampal alpha7 nicotinic acetylcholine receptors: In vitro and in vivo mechanisms related to Alzheimer's disease

Alzheimer's Disease (AD) is the most common of the senile dementias, the prevalence of which is increasing rapidly, with a projected 14 million affected worldwide by 2025. The signal transduction mechanisms that underlie the learning and memory derangements in AD are poorly understood. beta-Amyloid (Abeta) peptides are elevated in brain tissue of AD patients and are the principal component of amyloid plaques, a major criterion for postmortem diagnosis of the disease. Using acute and organotypic hippocampal slice preparations, we demonstrate that Abeta peptide 1-42 (Abeta42) couples to the mitogen-activated protein kinase (MAPK) cascade via alpha7 nicotinic acetylcholine receptors (nAChRs). In vivo elevation of Abeta, such as that exhibited in an animal model for AD, leads to the upregulation of alpha7 nAChR protein. alpha7 nAChR upregulation occurs concomitantly with the downregulation of the 42 kDa isoform of extracellular signal-regulated kinase (ERK2) MAPK in hippocampi of aged animals. The phosphorylation state of a transcriptional mediator of long-term potentiation and a downstream target of the ERK MAPK cascade, the cAMP-regulatory element binding (CREB) protein, were affected also. These findings support the model that derangement of hippocampus signal transduction cascades in AD arises as a consequence of increased Abeta burden and chronic activation of the ERK MAPK cascade in an alpha7 nAChR-dependent manner that eventually leads to the downregulation of ERK2 MAPK and decreased phosphorylation of CREB protein.

Enhancement of nigral graft survival in rat brain with the systemic administration of synthetic fibronectin peptide V

A major obstacle in neural transplantation is a severe loss of neurons in grafts soon after implantation. In the present study, we have investigated whether the systemic administration of synthetic fibronectin peptide V can increase the survival of neural grafts. Synthetic fibronectin peptide V is derived from the 33,000 mol. wt carboxyl-terminal heparin-binding domain of fibronectin. Previous studies have shown that these polypeptides possess anti-inflammatory properties. However, it is currently unknown whether this peptide has anti-apoptotic properties. Dissociated neural grafts were prepared from the ventral mesencephalon of pregnant Sprague-Dawley rats and were stereotaxically injected as a cell suspension into the striatum of adult Sprague-Dawley rats. A group of recipient rats received i.v. injections of peptide V (5mg/kg, dissolved in saline) at 24 and 4h prior to transplantation, at the time of transplantation, and 24, 48 and 72h post-transplantation. Saline-treated rats served as controls. The rats were killed at two, four and 42 days post-grafting and the brain tissue was immunologically processed for tyrosine-hydroxylase, major histocompatibility complex class I and class II antigens, complement receptor type 3 and leukocyte common antigen immunocytochemistry, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay. We found a significant increase (approximately twofold) in the number of dopamine neurons in the grafts for the peptide-treated group at four and 42 days compared with the controls. In contrast, there was no significant difference in the patterns of inflammation using different immunocytochemical markers in the two different groups. The levels of expression for these markers, however, were reduced over time. Interestingly, the number of apoptotic cells in the graft areas was significantly smaller in the peptide-treated group than in the control group two days after grafting. The results demonstrate that the systemic administration of synthetic fibronectin peptide V can dramatically increase the survival of nigral grafts in the brain and substantially reduce the number of apoptotic cells in the graft site, suggesting that this peptide may exert a beneficial effect on survival of nigral grafts through an anti-apoptotic mechanism.

Survival of intrastriatal xenografts of ventral mesencephalic dopamine neurons from MHC-deficient mice to adult rats

Previous studies of neural xenografts have used immunosuppressive agents to prevent graft rejection. In the present study we have examined the survival of mouse dopamine neurons lacking either MHC class I or MHC class II molecules transplanted into rat brains and the host immune and inflammatory responses against the xenografts. Survival of neural grafts was immunocytochemically determined at 4 days, 2 weeks, and 6 weeks after transplantation by counting tyrosine hydroxylase (TH)-positive cells in the graft areas. In addition, the host immune and inflammatory responses against neural xenografts were evaluated by semiquantitatively rating MHC class I and class II antigen expression, accumulation of macrophages and activated microglia, and infiltration of CD4- and CD8-positive T-lymphocytes. For the negative controls, the mean number of TH-positive cells in rats that received wild-type mouse tissue progressively decreased at various time periods following transplantation. In contrast, intrastriatal grafting of either MHC class I or MHC class II antigen-depleted neural xenografts resulted in a prolonged survival and were comparable to cyclosporin A-treated rats that had received wild-type mouse tissue. These results indicate that genetically modified donor tissue lacking MHC molecules can be used to prevent neural xenograft rejection.

Molecular relationships of the Australian bandicoot genera Isoodon and Perameles (Marsupialia: Peramelina)

12S rRNA sequences resolve the two Australian bandicoot genera Perameles and Isoodon as monophyletic clades which diverged from one another in the middle Miocene. Perameles bougainville, the most divergent species of this genus, appears to have split from the P. gunnii + P. nasuta lineage in the late Miocene, whilst subsequent speciation events occurred in the latter half of the Pliocene. Within Isoodon, although there was a clear recognition of an I. macrourus group of taxa, little support could be found for the continued recognition of the Tasmanian I. obesulus and the Barrow Island form of I. auratus as separate subspecies. Major radiations within Isoodon appear to have occurred in the last 3 million years as Australia became more arid.

Chromosome painting in marsupials: genome conservation in the kangaroo family

In order to deduce the ancestral genome arrangement in the karyotypically diverse marsupial family Macropodidae, and to assess chromosome change in this family, chromosome-specific paints from the tammar wallaby (2n = 16) were hybridized to metaphase spreads from the two species proposed to represent the 2n = 22 ancestral karyotype, as well as species with derived 2n = 20 and 2n = 14 karyotypes. Identical patterns were observed in the two 2n = 22 species, from which the rearrangements to form the three derived karyotypes may be easily deduced to be 1, 3 and 4 different fusions, respectively. The identical Thylogale and Dorcopsis genomes may both be used to represent the pleisiomorphic macropodid chromosome complement. Variation in the X chromosome was also investigated by hybridizing an X-Y shared tammar wallaby 12-kb repeat element to chromosomes from the other four macropodid species, finding that it hybridized only to the most closely related species, and therefore is of recent origin.

Systematic relationships within the dasyurid marsupial tribe Sminthopsini--a multigene approach

We report analyses of complete DNA sequences of the mitochondrial cytochrome b (1146 bp), 12S rRNA (974 bp), partial control region (371 bp) loci, and the nuclear protamine P1 (616 bp) gene from all but one species (Sminthopsis butleri) of the dasyurid marsupial tribe Sminthopsini, as well as several outgroups. Parsimony analyses of combined nuclear and mitochondrial data suggest that Antechinomys is sister to a clade consisting of Sminthopsis and Ningaui. Parsimony, maximum-likelihood, and mixed-model distance analyses consistently resolve several species groups within Sminthopsis. The Macroura group includes S. macroura, S. virginiae, S. douglasi, and S. bindi; S. butleri is also included here on the basis of partial 12S rRNA sequences. S. crassicaudata is resolved as sister to the Macroura clade. The Murina group includes S. murina, S. leucopus, S. gilberti, S. dolichura, and S. archeri. S. griseoventer and S. aitkeni are resolved as a clade, and there is moderate support for a group consisting of the genetically divergent species S. psammophila, S. hirtipes, S. youngsoni, and S. ooldea (possibly along with S. longicaudata and S. granulipes). Compositions of species groups are partially congruent with clades previously proposed on the basis of morphological data. Radiations within Sminthopsini appear to be coincident with major environmental changes since the mid-Miocene.

The origin of the Australasian marsupial fauna and the phylogenetic affinities of the enigmatic monito del monte and marsupial mole

Alternative hypotheses in higher-level marsupial systematics have different implications for marsupial origins, character evolution, and biogeography. Resolving the position of the South American monito del monte (Order Microbiotheria) is of particular importance in that alternate hypotheses posit sister-group relationships between microbiotheres and taxa with disparate temporal and geographic distributions: pediomyids; didelphids; dasyuromorphians; diprotodontians; all other australidelphians; and all other marsupials. Among Australasian marsupials, the placement of bandicoots is critical; competing views associate bandicoots with particular Australasian taxa (diprotodontians, dasyuromorphians) or outside of a clade that includes all other Australasian forms and microbiotheres. Affinities of the marsupial mole are also unclear. The mole is placed in its own order (Notoryctemorphia) and sister-group relationships have been postulated between it and each of the other Australasian orders. We investigated relationships among marsupial orders by using a data set that included mitochondrial and nuclear genes. Phylogenetic analyses provide support for the association of microbiotheres with Australasian marsupials and an association of the marsupial mole with dasyuromorphs. Statistical tests reject the association of diprotodontians and bandicoots together as well as the monophyly of Australasian marsupials. The origin of the paraphyletic Australasian marsupial fauna may be accounted for by (i) multiple entries of australidelphians into Australia or (ii) bidirectional dispersal of australidelphians between Antarctica and Australia.

Conflict among individual mitochondrial proteins in resolving the phylogeny of eutherian orders

The phylogenetic relationship among primates, ferungulates (artiodactyls + cetaceans + perissodactyls + carnivores), and rodents was examined using proteins encoded by the H strand of mtDNA, with marsupials and monotremes as the outgroup. Trees estimated from individual proteins were compared in detail with the tree estimated from all 12 proteins (either concatenated or summing up log-likelihood scores for each gene). Although the overall evidence strongly suggests ((primates, ferungulates), rodents), the ND1 data clearly support another tree, ((primates, rodents), ferungulates). To clarify whether this contradiction is due to (1) a stochastic (sampling) error; (2) minor model-based errors (e.g., ignoring site rate variability), or (3) convergent and parallel evolution (specifically between either primates and rodents or ferungulates and the outgroup), the ND1 genes from many additional species of primates, rodents, other eutherian orders, and the outgroup (marsupials + monotremes) were sequenced. The phylogenetic analyses were extensive and aimed to eliminate the following artifacts as possible causes of the aberrant result: base composition biases, unequal site substitution rates, or the cumulative effects of both. Neither more sophisticated evolutionary analyses nor the addition of species changed the previous conclusion. That is, the statistical support for grouping rodents and primates to the exclusion of all other taxa fluctuates upward or downward in quite a tight range centered near 95% confidence. These results and a site-by-site examination of the sequences clearly suggest that convergent or parallel evolution has occurred in ND1 between primates and rodents and/or between ferungulates and the outgroup. While the primate/rodent grouping is strange, ND1 also throws some interesting light on the relationships of some eutherian orders, marsupials, and montremes. In these parts of the tree, ND1 shows no apparent tendency for unexplained convergences.

The phylogenetic position of the musky rat-kangaroo and the evolution of bipedal hopping in kangaroos (Macropodidae: Diprotodontia)

Kangaroos and their relatives (family Macropodidae) are divided into the subfamilies Macropodinae (kangaroos, wallabies, pademelons) and Potoroinae (rat-kangaroos, potoroos, bettongs). The musky rat-kangaroo, Hypsiprymnodon moschatus, is traditionally allied with other potoroines, based primarily on the basis of osteological characters and aspects of the female reproductive system. Unlike other macropodids, however, which are capable of bipedal hopping, Hypsiprymnodon is a quadrupedal bounder and lacks several derived features of the pes and tarsus that are presumably adaptations for bipedal hopping. Other derived features, such as a complex stomach, loss of P2 with the eruption of P3, and reduction of litter size to one, are also lacking in Hypsiprymnodon but occur in all other macropodids. Thus, available evidence suggests that Hypsiprymnodon either is part of a monophyletic Potoroinae or is a sister taxon to other living macropodids. To test these hypotheses, we sequenced 1,170 bp base pairs of the mitochondrial genome for 16 macropodids. Maximum parsimony, minimum evolution, maximum likelihood, and quartet puzzling all support the hypothesis that macropodines and potoroines are united to the exclusion of Hypsiprymnodon. This hypothesis implies that characters such as bipedal hopping evolved only once in macropodid evolution. Aside from Hypsiprymnodon, the remaining macropodids separate into the traditional Macropodinae and Potoroinae. Macropodines further separate into two clades: one containing the New Guinean forest wallabies Dorcopsis and Dorcopsulus, and one consisting of the genera Macropus, Setonix, Thylogale, Onychogalea, Wallabia, Dendrolagus, Peradorcas, and Lagorchestes. Among potoroines, there is moderate support for the association of Bettongia and Aepyprymnus to the exclusion of Potorous. Divergence times were estimated by using 12S ribosomal RNA transversions. At the base of the macropodid radiation, Hypsiprymnodon diverged from other macropodids approximately 45 million years ago. This estimate is comparable to divergence estimates among families of Australasian possums based on single-copy DNA hybridization and 12S rRNA transversions. Macropodines and potoroines, in turn, diverged approximately 30 million years ago. Among macropodines, Dorcopsis and Dorcopsulus separated from other taxa approximately 10 million years ago.

A multigene assessment of phylogenetic relationships within the dasyurid marsupial subfamily Sminthopsinae

We report sequences of the mitochondrial cytochrome b (1146 bp) and 12S rRNA (961 bp) genes, as well as the nuclear protamine P1 (608 bp) gene, from 13 species representing all four genera of the dasyurid marsupial subfamily Sminthopsinae. Mitochondrial sequences are partitioned into five categories (three codon positions in cytochrome b, and stems and loops in 12S rRNA) with distinct substitution rates, transition biases, and base compositions. We extract estimates of these biases from the sequences and employ them to calculate two overall distances based on the DNAML model. Phylogenetic analyses using distance and parsimony methods yield trees with different topologies for mtDNA and protamine. These trees are compatible with respect to highly resolved nodes, but incompatible with respect to length differences in a parsimony framework. The tree from combined-data analysis is dominated by the larger data set (mtDNA). The balance of evidence favors a basal separation of Planigale from other sminthopsines. Within Planigale, Pl. maculata is sister to the remaining species. Although the precise intergeneric affinities of Antechinomys are unresolved, A. laniger does not appear to be part of the genus Sminthopsis as suggested by morphological data. The 12S rRNA resolves Ningaui ridei and N. yvonnae as sister species.

DNA phylogeny of the marsupial wolf resolved

The phylogenetic position of the recently extinct marsupial 'wolf', or thylacine (Thylacinus cynocephalus), has been a source of contention in mammalian systematics for nearly a century. Thylacines were endemic to Australasia, but possessed striking anatomical similarities to Oligo-Miocene borhyaenid marsupials of South America. At issue has been whether these features are indicative of common ancestry or convergent adaptation to carnivory. Recent morphological studies have supported both conclusions. Although current marsupial classifications group thylacines with Australian dasyuromorphians, this putative clade is characterized by mostly primitive morphological features. Attempts to determine thylacine affinities with ancient protein and DNA analyses have supported, but not resolved, a dasyuromorphian placement. We report 1546 bp of mitochondrial DNA sequence (from cytochrome b and 12S rRNA genes) and 841 bp of nuclear protamine gene sequence from the thylacine and representatives of all or most other marsupial orders. Phylogenetic analysis of these sequences shows unambiguously that thylacines are members of Dasyuromorphia, and suggests a late Oligocene or very early Miocene divergence of familial lineages.