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1.
Ann Oncol ; 31(1): 61-71, 2020 01.
Article in English | MEDLINE | ID: mdl-31912797

ABSTRACT

In patients with operable early breast cancer, neoadjuvant systemic treatment (NST) is a standard approach. Indications have expanded from downstaging of locally advanced breast cancer to facilitate breast conservation, to in vivo drug-sensitivity testing. The pattern of response to NST is used to tailor systemic and locoregional treatment, that is, to escalate treatment in nonresponders and de-escalate treatment in responders. Here we discuss four questions that guide our current thinking about 'response-adjusted' surgery of the breast after NST. (i) What critical diagnostic outcome measures should be used when analyzing diagnostic tools to identify patients with pathologic complete response (pCR) after NST? (ii) How can we assess response with the least morbidity and best accuracy possible? (iii) What oncological consequences may ensue if we rely on a nonsurgical-generated diagnosis of, for example, minimally invasive biopsy proven pCR, knowing that we may miss minimal residual disease in some cases? (iv) How should we design clinical trials on de-escalation of surgical treatment after NST?


Subject(s)
Breast Neoplasms , Antineoplastic Combined Chemotherapy Protocols , Breast , Breast Neoplasms/drug therapy , Breast Neoplasms/surgery , Humans , Mastectomy , Neoadjuvant Therapy , Neoplasm, Residual , Treatment Outcome
2.
Br J Surg ; 105(5): 535-543, 2018 04.
Article in English | MEDLINE | ID: mdl-29465744

ABSTRACT

BACKGROUND: Patients with triple-negative breast cancer (TNBC) and a pathological complete response (pCR) after neoadjuvant chemotherapy may be suitable for non-surgical management. The goal of this study was to identify baseline clinicopathological variables that are associated with residual disease, and to evaluate the effect of neoadjuvant chemotherapy on both the invasive and ductal carcinoma in situ (DCIS) components in TNBC. METHODS: Patients with TNBC treated with neoadjuvant chemotherapy followed by surgical resection were identified. Patients with a pCR were compared with those who had residual disease in the breast and/or lymph nodes. Clinicopathological variables were analysed to determine their association with residual disease. RESULTS: Of the 328 patients, 36·9 per cent had no residual disease and 9·1 per cent had residual DCIS only. Patients with residual disease were more likely to have malignant microcalcifications (P = 0·023) and DCIS on the initial core needle biopsy (CNB) (P = 0·030). Variables independently associated with residual disease included: DCIS on CNB (odds ratio (OR) 2·46; P = 0·022), T2 disease (OR 2·40; P = 0·029), N1 status (OR 2·03; P = 0·030) and low Ki-67 (OR 2·41; P = 0·083). Imaging after neoadjuvant chemotherapy had an accuracy of 71·7 (95 per cent c.i. 66·3 to 76·6) per cent and a negative predictive value of 76·9 (60·7 to 88·9) per cent for identifying residual disease in the breast and lymph nodes. Neoadjuvant chemotherapy did not eradicate the DCIS component in 55 per cent of patients. CONCLUSION: The presence of microcalcifications on imaging and DCIS on initial CNB are associated with residual disease after neoadjuvant chemotherapy in TNBC. These variables can aid in identifying patients with TNBC suitable for inclusion in trials evaluating non-surgical management after neoadjuvant chemotherapy.


Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Ductal, Breast/drug therapy , Conservative Treatment/methods , Neoplasm Staging , Triple Negative Breast Neoplasms/drug therapy , Adult , Aged , Carcinoma, Ductal, Breast/pathology , Chemotherapy, Adjuvant , Female , Follow-Up Studies , Humans , Middle Aged , Neoadjuvant Therapy , Prospective Studies , Treatment Outcome , Triple Negative Breast Neoplasms/pathology
3.
Unfallchirurg ; 120(8): 675-682, 2017 Aug.
Article in German | MEDLINE | ID: mdl-27357352

ABSTRACT

BACKGROUND: The application of cervical collars is a standard procedure in emergency care of trauma patients. It is often observed that the application of cervical collars is performed incorrectly, which may lead to reduced immobilization of the cervical spine. OBJECTIVES: The objective of this study was to analyze the practical skills of professional emergency care providers concerning the application of cervical collars. MATERIALS AND METHODS: Emergency care professionals (n = 104) were asked to apply a cervical collar to a training doll. Each performance step was assessed separately. Furthermore, personal and occupational data of all study participants were collected using a questionnaire. RESULTS: The study participants included professional rescue personnel and emergency physicians. The average occupational experience of all study participants in out-of-hospital emergency care was 11.1 ± 8.9 years. Most participants had already received training on trauma care (61 %) and felt "very confident" in handling a cervical collar (84 %). The application of the cervical collar was performed correctly in 11 % of the performances. The most common error was incorrect size adjustment of the cervical collar (66 %). No association was found between the correct application of the cervical collar and possible parameters of influence, such as working experience in emergency care or participation in trauma courses. CONCLUSIONS: Despite pronounced subjective confidence regarding the application of cervical collars, this study shows that there are general deficits in the practical skills of applying cervical collars. Therefore, a critical assessment of the current training contents on the subject of trauma care must be demanded.


Subject(s)
Cervical Vertebrae/injuries , Emergency Medical Services/methods , Fracture Fixation/methods , Immobilization/methods , Spinal Fractures/therapy , Adolescent , Adult , Clinical Competence , Female , Fracture Fixation/instrumentation , Humans , Immobilization/instrumentation , Inservice Training , Male , Middle Aged , Models, Anatomic , Young Adult
4.
Ann Surg Oncol ; 23(3): 789-95, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26467456

ABSTRACT

BACKGROUND: This study evaluated breast imaging procedures for predicting pathologic complete response (pCR = ypT0) after neoadjuvant chemotherapy (NACT) for breast cancer to challenge surgery as a diagnostic procedure after NACT. METHODS: This retrospective, exploratory, monocenter study included 150 invasive breast cancers treated by NACT. The patients received magnetic resonance imaging (MRI), mammography (MGR), and ultrasound (US). The results were classified in three response subgroups according to response evaluation criteria in solid tumors. To incorporate specific features of MRI and MGR, an additional category [clinical near complete response (near-cCR)] was defined. Residual cancer in imaging and pathology was defined as a positive result. Negative predictive values (NPVs), false-negative rates (FNRs), and false-positive rates (FPRs) of all imaging procedures were analyzed for the whole cohort and for triple-negative (TN), HER2-positive (HER2+), and HER2-negative/hormone-receptor-positive (HER2-/HR+) cancers, respectively. RESULTS: In 46 cases (31%), pCR (ypT0) was achieved. Clinical complete response (cCR) and near-cCR showed nearly the same NPVs and FNRs. The NPV was highest with 61% for near-cCR in MRI and lowest with 44% for near-cCR in MGR for the whole cohort. The FNRs ranged from 4 to 25% according to different imaging methods. The MRI performance seemed to be superior, especially in TN cancers (NPV 94%; FNR 5%). The lowest FPR was 10 % in MRI, and the highest FPR was 44% in US. CONCLUSION: Neither MRI nor MGR or US can diagnose a pCR (ypT0) with sufficient accuracy to replace pathologic diagnosis of the surgical excision specimen.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Diagnostic Imaging/methods , Multimodal Imaging , Neoadjuvant Therapy , Triple Negative Breast Neoplasms/diagnosis , Triple Negative Breast Neoplasms/drug therapy , Biomarkers, Tumor/metabolism , Chemotherapy, Adjuvant , Female , Follow-Up Studies , Humans , Immunoenzyme Techniques , Middle Aged , Neoplasm Grading , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , Receptor, ErbB-2/metabolism , Receptors, Estrogen/metabolism , Receptors, Progesterone/metabolism , Retrospective Studies , Triple Negative Breast Neoplasms/metabolism
5.
Eur J Neurol ; 22(10): 1355-62, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25557113

ABSTRACT

BACKGROUND AND PURPOSE: Cerebral microbleeds (CMBs) are associated with an increased risk of intracerebral hemorrhage. The impact of oral anticoagulation (OAC) on CMBs is not well characterized. Our aim was to assess the prevalence of CMBs in stroke and transient ischaemic attack (TIA) patients with atrial fibrillation (AF) and to analyze the implications of previous treatment with OAC. METHODS: In this retrospective analysis on data from a prospectively recruiting stroke registry, patients with ischaemic stroke or TIA with brain magnetic resonance imaging including susceptibility weighted imaging were consecutively enrolled during a 3-year period. For each patient cardiovascular risk factors, AF history and recent diagnosis of AF, present use of OAC and antiplatelets, the National Institute of Health Stroke Scale and the premorbid modified Rankin Scale score were recorded. Two independent raters identified CMBs according to consensus criteria. CMB location was classified as lobar, deep or in the posterior fossa. RESULTS: In all, 785 patients (mean age 63.9 ± 14.2 years) were included. At least one CMB was detected in 186 (23.7%) patients. CMBs were significantly more frequent in patients with AF (30.5% vs. 22.4%). Patients with previous OAC treatment were more likely to have CMBs (36.7% vs. 22.8%, P = 0.03) and abundant CMBs (n > 10) were more frequent in anticoagulated patients even after adjustment for age. However, age was the only independent factor predicting CMBs (P = 0.001). CONCLUSIONS: Cerebral microbleeds are common in elderly AF patients with acute ischaemic stroke. Previous OAC is associated with a higher number of CMBs predominantly in the lobar location. Establishing a causal relationship requires prospective longitudinal investigation.


Subject(s)
Anticoagulants/adverse effects , Atrial Fibrillation , Cerebral Hemorrhage/etiology , Ischemic Attack, Transient/drug therapy , Registries , Stroke/drug therapy , Aged , Aged, 80 and over , Atrial Fibrillation/epidemiology , Cerebral Hemorrhage/epidemiology , Comorbidity , Female , Humans , Ischemic Attack, Transient/epidemiology , Male , Middle Aged , Prevalence , Prospective Studies , Retrospective Studies , Stroke/epidemiology
6.
Eur J Neurol ; 22(1): 64-9, e4-5, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25091540

ABSTRACT

BACKGROUND AND PURPOSE: Chronic kidney disease (CKD) is associated with a higher risk of stroke and atrial fibrillation (AF). There are limited data on the comorbidity of renal dysfunction and AF in stroke patients. Our aim was to determine the frequency of kidney dysfunction in ischaemic stroke patients with and without AF. METHODS: In a prospectively collected, single center cohort of acute ischaemic stroke and transient ischaemic attack (TIA) patients, glomerular filtration rate (eGFR) was estimated using the Modification of Diet in Renal Disease equation on admission. Renal function was graded into five categories (cat.): cat. 1, eGRF ≥90 ml/min/1.73 m(2); cat. 2, 60-89; cat. 3, 30-59; cat. 4, 15-29; cat. 5, <15. The diagnosis of AF was based on medical history, a 12-lead electrocardiogram (ECG) and 24-h Holter or continuous ECG monitoring. RESULTS: In total, 2274 patients (1727 stroke, 547 TIA; median age 71.0) were included. Median eGFR was 78.6 ml/min/1.73 m(2) (interquartile range 61/95); 21.1% were in cat. 3, 2.1% in cat. 4, 0.7% in cat. 5. In all, 535 patients (23.5%) suffered from AF; 28.0% of these were in cat. 3, 2.6% and 0.8% in cat. 4 and cat. 5, respectively. In multivariable analysis, age [odds ratio (OR) 1.1], diabetes (OR 1.8), heart failure (OR 1.7) and AF (OR 1.4) were independently associated with kidney dysfunction (eGFR < 60). CONCLUSIONS: Renal dysfunction is far more common in stroke patients than in the general population and more common in AF-related stroke. These findings may have implications for the choice of anticoagulants.


Subject(s)
Atrial Fibrillation/epidemiology , Brain Ischemia/epidemiology , Kidney Diseases/epidemiology , Registries , Stroke/epidemiology , Aged , Aged, 80 and over , Atrial Fibrillation/diagnosis , Cohort Studies , Comorbidity , Electrocardiography , Female , Germany/epidemiology , Glomerular Filtration Rate , Humans , Ischemic Attack, Transient/epidemiology , Kidney Diseases/classification , Kidney Diseases/diagnosis , Male , Middle Aged , Prevalence
7.
Eur J Neurol ; 21(11): 1387-93, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25040216

ABSTRACT

BACKGROUND AND PURPOSE: Cognitive deficits are common following stroke. Cognitive function in the acute stroke setting is a predictive factor for mid-term outcome. The Montreal Cognitive Assessment (MoCA) is a screening tool for cognitive impairment. The feasibility of MoCA in the acute phase of stroke was evaluated and factors predictive of cognitive impairment were determined. METHODS: In this prospective, single-centre, explorative and observational study consecutive patients with ischaemic (IS) or haemorrhagic (ICH) stroke were enrolled between March 2011 and September 2012. The routine work-up for each patient encompassed assessment of cardiovascular risk factors, the National Institutes of Health Stroke Scale (NIHSS) and the pre-morbid modified Rankin Scale (mRS) score. Cognitive performance was measured using the German version of the MoCA within the first days of admission. A MoCA score of <26 was considered to indicate cognitive impairment. RESULTS: Between March 2011 and September 2012 a total of 842 patients with IS (89.0%) and ICH (11.0%) were enrolled in our study. MoCA was feasible in 678/842 patients (80.5%). Factors independently associated with non-feasibility were stroke severity (NIHSS), pre-morbid functional status (mRS), age and lower educational level. Mean MoCA was 21.4 (SD 5.7). A total of 498/678 (73.5%) patients appeared cognitively impaired (<26/30). Independent predictive factors for a lower MoCA score were age, educational level, stroke severity (NIHSS) and pre-morbid functional status (mRS). CONCLUSIONS: In the acute phase of stroke, MoCA is feasible in about 80% of eligible patients. At this stage, MoCA identifies a cognitive impairment in 75% of patients.


Subject(s)
Cognition Disorders/diagnosis , Neuropsychological Tests/standards , Psychometrics/instrumentation , Stroke/diagnosis , Aged , Aged, 80 and over , Cardiovascular Diseases/complications , Cognition Disorders/etiology , Feasibility Studies , Female , Humans , Male , Middle Aged , Prospective Studies , Stroke/complications
8.
J Evol Biol ; 27(4): 796-800, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24779056

ABSTRACT

Parasites with exclusive vertical transmission from host parent to offspring are an evolutionary puzzle. With parasite fitness entirely linked to host reproduction, any fitness cost for infected hosts risks their selective elimination. Environmental conditions likely influence parasite impact and thereby the success of purely vertical transmission strategies. We tested for temperature-dependent virulence of Caedibacter taeniospiralis, a vertically transmitted bacterial symbiont of the protozoan Paramecium tetraurelia. We compared growth of infected and cured host populations at five temperatures (16­32 °C). Infection reduced host density at all temperatures, with a peak of −30% at 28 °C. These patterns were largely consistent across five infected Paramecium strains. Similar to Wolbachia symbionts, C. taeniospiralis may compensate fitness costs by conferring to the host a 'killer trait', targeting uninfected competitors. Considerable loss of infection at 32 °C suggests that killer efficacy is not universal and that limited heat tolerance restricts the conditions for persistence of C. taeniospiralis.


Subject(s)
Gammaproteobacteria/pathogenicity , Genetic Fitness , Paramecium tetraurelia/microbiology , Symbiosis , Temperature
9.
Pol J Vet Sci ; 17(4): 733-5, 2014.
Article in English | MEDLINE | ID: mdl-25638991

ABSTRACT

A Cyprinid herpesvirus 3 infection of carp induces a disease which causes substantial losses in carp culture. Here we present the use of a possible strategy for the management of the virus infection RNA interference based on small interfering RNAs. As a result of in vitro studies, we found that a mixture of short interfering RNAs specific for viral DNA enzyme synthesis and capsid proteins of the CyHV-3 can be a potential inhibitor of virus replication in fibroblastic cells. This gives the basis for the development of a combinatorial RNA interference strategy to treat CyHV-3 infections.


Subject(s)
Capsid Proteins/metabolism , Fibroblasts/virology , Herpesviridae/physiology , RNA Interference/physiology , RNA, Small Interfering/genetics , Animals , Capsid Proteins/genetics , Cell Death , Cell Line , Fibroblasts/physiology , Fishes , Gene Expression Regulation, Viral , Herpesviridae/genetics , Virus Replication
10.
Stat Med ; 32(21): 3595-608, 2013 Sep 20.
Article in English | MEDLINE | ID: mdl-23553898

ABSTRACT

Composite endpoints combine several events of interest within a single variable. These are often time-to-first-event data, which are analyzed via survival analysis techniques. To demonstrate the significance of an overall clinical benefit, it is sufficient to assess the test problem formulated for the composite. However, the effect observed for the composite does not necessarily reflect the effects for the components. Therefore, it would be desirable that the sample size for clinical trials using composite endpoints provides enough power not only to detect a clinically relevant superiority for the composite but also to address the components in an adequate way. The single components of a composite endpoint assessed as time-to-first-event define competing risks. We consider multiple test problems based on the cause-specific hazards of competing events to address the problem of analyzing both a composite endpoint and its components. Thereby, we use sequentially rejective test procedures to reduce the power loss to a minimum. We show how to calculate the sample size for the given multiple test problem by using a simply applicable simulation tool in SAS. Our ideas are illustrated by two clinical study examples.


Subject(s)
Clinical Trials as Topic/methods , Endpoint Determination/methods , Research Design , Survival Analysis , Angiotensin II Type 1 Receptor Blockers/therapeutic use , Atherosclerosis/drug therapy , Computer Simulation , Diabetes Mellitus, Type 2/drug therapy , Diabetic Nephropathies/drug therapy , Humans , Losartan/therapeutic use , Sample Size , Thrombin/antagonists & inhibitors
11.
Breast ; 21(3): 303-8, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22310244

ABSTRACT

INTRODUCTION: Evaluation of oncological outcome and prognostic factors of patients with primary breast cancer treated at a certified academic breast unit. PATIENTS AND METHODS: We prospectively collected data of 3338 patients, diagnosed with primary breast cancer between 01.01.2003 and 31.12.2010 and treated at the Breast Unit Heidelberg, Germany, in order to analyze outcome in clinical practice. We evaluated local control rate (LCR), disease-free survival (DFS), distant disease-free survival (DDFS), observed overall survival (OS) and age-adjusted relative overall survival (ROS). In addition, the impact of known prognostic factors on these outcome variables was examined in univariate and multivariate analyses. RESULTS: Of all patients, 368 (11.0%) had carcinoma in situ (CIS) and 197 (5.9%) had bilateral cancers. For the 2970 patients with invasive cancer, of which 49 patients (1.7%) had metastastic disease at time of diagnosis, DFS, LCR, DDFS, OS and ROS at 5 years were 79.8%, 84.7%, 81.2%, 86.3%, and 89.8%, respectively. In multivariate analysis age, pT category, nodal status, hormone receptor status and grading were identified as independent prognostic factors for OS. CONCLUSION: Compared with recent population-based reports from Germany, more favourable patient characteristics and nominally higher survival was found among this large cohort of patients with primary breast cancer treated at a single certified breast unit.


Subject(s)
Academic Medical Centers/statistics & numerical data , Breast Neoplasms/epidemiology , Breast Neoplasms/therapy , Carcinoma/epidemiology , Carcinoma/therapy , Women's Health , Adult , Age Factors , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Breast Neoplasms/pathology , Carcinoma/pathology , Chemotherapy, Adjuvant , Combined Modality Therapy , Disease-Free Survival , Female , Germany , Humans , Middle Aged , Prognosis , Prospective Studies , Radiotherapy, Adjuvant , Survival Rate , Treatment Outcome , Young Adult
12.
Ann Oncol ; 23(1): 98-104, 2012 Jan.
Article in English | MEDLINE | ID: mdl-21460377

ABSTRACT

BACKGROUND: Breast magnetic resonance imaging (MRI) has been introduced in the preoperative management of invasive lobular breast cancer (ILC). We analysed if MRI leads to adequate changes in surgical management. PATIENTS AND METHODS: We carried out a single-centre retrospective confirmatory analysis of 92 patients with ILC and a preoperative breast MRI. By applying a blinded tumour board method, we analysed if surgical procedures were altered due to breast MRI. In case of alteration, we analysed whether the change was adequate according to the postoperative pathology findings. We considered an adequate rate of change>5% to be a clinically relevant benefit. RESULTS: A change in surgical therapy due to the MRI findings occurred in 23 of 92 patients (25%). According to the postoperative pathology findings, this change was adequate for 20 of these patients (22%; 95% confidence interval [CI] 14%-31%, P<0.0001). An overtreatment occurred for three patients (3%; 95% CI 0%-6%) who underwent a mastectomy following the results of breast MRI. Patients with larger tumours did likely benefit more from preoperative breast MRI. CONCLUSIONS: Patients with ILC might benefit from a preoperative breast MRI. Possible harm from overtreatment should be minimised by diligent use of preoperative histological clarification.


Subject(s)
Breast Neoplasms/pathology , Breast Neoplasms/surgery , Carcinoma, Lobular/pathology , Carcinoma, Lobular/surgery , Magnetic Resonance Imaging , Female , Humans , Mastectomy , Neoplasm Staging , Preoperative Care/methods , Retrospective Studies
13.
Eur J Surg Oncol ; 37(2): 116-21, 2011 Feb.
Article in English | MEDLINE | ID: mdl-21130597

ABSTRACT

PURPOSE: We analyzed changes in aesthetic and functional outcome over time after breast conserving therapy. Our special interest resides in the question of whether these aspects gain or loose their influence on quality of life (QoL) with temporal progress. PATIENTS AND METHODS: This prospective single centre cohort study included 138 patients, treated with breast conserving surgery and consecutive radiotherapy. Patients completed two questionnaires one week and one year after surgery: the BCTOS (Breast Cancer Treatment Outcome Scale) to measure Functional, Aesthetic, and Breast Sensitivity Status and the EORTC (European Organisation for Research and Treatment of Cancer) C30-BR23 to assess QoL. We applied correlation and multiple regression analysis as statistical methods. RESULTS: Aesthetic and Functional Status did not change significantly over one year, whereas Breast Sensitivity Status and several QoL subscales showed significant improvement (p < 0.0001). Correlations between BCTOS scales and EORTC subscales remain similar over time. Functional and Aesthetic Status kept a strong impact on global health (Spearman's Rho = -0.28 to -0.45 depending on time of assessment). Increasing age and poorer Functional Status shortly after surgery are predictors of a decline in global health over one year (p < 0.001). CONCLUSION: Functional and aesthetic outcome after breast conserving surgery maintain their impact on QoL over a one year follow-up period and are valuable predictors of QoL.


Subject(s)
Breast Neoplasms/surgery , Mastectomy, Segmental/psychology , Quality of Life , Adult , Aged , Female , Humans , Middle Aged , Prospective Studies , Time Factors
14.
Mol Ecol ; 15(4): 1153-64, 2006 Apr.
Article in English | MEDLINE | ID: mdl-16599974

ABSTRACT

Genes of the major histocompatibility complex (MHC) have been studied for several decades because of their pronounced allelic polymorphism. Structural allelic polymorphism is, however, not the only source of variability subjected to natural selection. Genetic variation may also exist in gene expression patterns. Here, we show that in a natural population of three-spined sticklebacks (Gasterosteus aculeatus) the expression of MHC class IIB genes was positively correlated with parasite load, which indicates increased immune activation of the MHC when infections are frequent. To experimentally study MHC expression, we used laboratory-bred sticklebacks that were exposed to three naturally occurring species of parasite. We found strong differences in MHC class IIB expression patterns among fish families, which were consistent over two generations, thus demonstrating a genetic component. The average number of MHC class IIB sequence variants within families was negatively correlated to the MHC expression level suggesting compensatory up-regulation in fish with a low (i.e. suboptimal) MHC sequence variability. The observed differences among families and the negative correlation with individual sequence diversity imply that MHC expression is evolutionary relevant for the onset and control of the immune response in natural populations.


Subject(s)
Fish Proteins/genetics , Genes, MHC Class II , Polymorphism, Genetic , Smegmamorpha/genetics , Alleles , Analysis of Variance , Biological Evolution , Fish Proteins/metabolism , Genotype , Host-Parasite Interactions/genetics , Models, Biological , Selection, Genetic , Smegmamorpha/parasitology , Tissue Distribution
15.
J Evol Biol ; 18(4): 1069-75, 2005 Jul.
Article in English | MEDLINE | ID: mdl-16033580

ABSTRACT

How complex life cycles of parasites are maintained is still a fascinating and unresolved topic. Complex life cycles using three host species, free-living stages, asexual and sexual reproduction are widespread in parasitic helminths. For such life cycles, we propose here that maintaining a second intermediate host in the life cycle can be advantageous for the individual parasite to increase the intermixture of different clones and therefore decrease the risk of matings between genetically identical individuals in the definitive host. Using microsatellite markers, we show that clone mixing occurs from the first to the second intermediate host in natural populations of the eye-fluke Diplostomum pseudospathaceum. Most individuals released by the first intermediate host belonged to one clone. In contrast, the second intermediate host was infected with a diverse array of mostly unique parasite genotypes. The proposed advantage of increased parasite clone intermixture may be a novel selection pressure favouring the maintenance of complex life cycles.


Subject(s)
Genetic Variation , Genetics, Population , Life Cycle Stages/physiology , Smegmamorpha/parasitology , Snails/parasitology , Trematoda/growth & development , Animals , Fresh Water , Genotype , Germany , Microsatellite Repeats/genetics , Population Dynamics , Reproduction/physiology , Selection, Genetic
16.
Development ; 128(16): 3081-94, 2001 Aug.
Article in English | MEDLINE | ID: mdl-11688558

ABSTRACT

We describe a new zebrafish mutation, neckless, and present evidence that it inactivates retinaldehyde dehydrogenase type 2, an enzyme involved in retinoic acid biosynthesis. neckless embryos are characterised by a truncation of the anteroposterior axis anterior to the somites, defects in midline mesendodermal tissues and absence of pectoral fins. At a similar anteroposterior level within the nervous system, expression of the retinoic acid receptor a and hoxb4 genes is delayed and significantly reduced. Consistent with a primary defect in retinoic acid signalling, some of these defects in neckless mutants can be rescued by application of exogenous retinoic acid. We use mosaic analysis to show that the reduction in hoxb4 expression in the nervous system is a non-cell autonomous effect, reflecting a requirement for retinoic acid signalling from adjacent paraxial mesoderm. Together, our results demonstrate a conserved role for retinaldehyde dehydrogenase type 2 in patterning the posterior cranial mesoderm of the vertebrate embryo and provide definitive evidence for an involvement of endogenous retinoic acid in signalling between the paraxial mesoderm and neural tube.


Subject(s)
Aldehyde Oxidoreductases/genetics , Mesoderm/metabolism , Mutation , Rhombencephalon/metabolism , Aldehyde Oxidoreductases/metabolism , Amino Acid Sequence , Animals , Cloning, Molecular , Ectoderm/metabolism , Genetic Linkage , Homeodomain Proteins/metabolism , In Situ Hybridization , In Situ Nick-End Labeling , Models, Biological , Models, Genetic , Molecular Sequence Data , Neural Crest/embryology , Notochord/embryology , Phenotype , RNA, Messenger/metabolism , Receptors, Retinoic Acid/metabolism , Retinal Dehydrogenase , Retinoic Acid Receptor alpha , Rhombencephalon/embryology , Sequence Homology, Amino Acid , Signal Transduction , Transcription Factors/metabolism , Tretinoin/metabolism , Tretinoin/pharmacology , Zebrafish , Zebrafish Proteins/agonists
17.
Genes Dev ; 15(11): 1427-34, 2001 Jun 01.
Article in English | MEDLINE | ID: mdl-11390362

ABSTRACT

Zebrafish embryos homozygous for the masterblind (mbl) mutation exhibit a striking phenotype in which the eyes and telencephalon are reduced or absent and diencephalic fates expand to the front of the brain. Here we show that mbl(-/-) embryos carry an amino-acid change at a conserved site in the Wnt pathway scaffolding protein, Axin1. The amino-acid substitution present in the mbl allele abolishes the binding of Axin to Gsk3 and affects Tcf-dependent transcription. Therefore, Gsk3 activity may be decreased in mbl(-/-) embryos and in support of this possibility, overexpression of either wild-type Axin1 or Gsk3beta can restore eye and telencephalic fates to mbl(-/-) embryos. Our data reveal a crucial role for Axin1-dependent inhibition of the Wnt pathway in the early regional subdivision of the anterior neural plate into telencephalic, diencephalic, and eye-forming territories.


Subject(s)
Body Patterning/genetics , Calcium-Calmodulin-Dependent Protein Kinases/genetics , Diencephalon/embryology , Eye/embryology , Proteins/genetics , Repressor Proteins , Telencephalon/embryology , Zebrafish Proteins , Animals , Axin Protein , Body Patterning/physiology , Calcium-Calmodulin-Dependent Protein Kinases/metabolism , Conserved Sequence , Diencephalon/growth & development , Diencephalon/metabolism , Embryo, Nonmammalian , Eye/metabolism , Glycogen Synthase Kinase 3 , In Situ Hybridization , Mutation , Precipitin Tests , Protein Binding , Protein Structure, Tertiary , Proteins/metabolism , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/physiology , Signal Transduction , Telencephalon/growth & development , Telencephalon/metabolism , Wnt Proteins , Zebrafish
18.
Development ; 128(6): 849-58, 2001 Mar.
Article in English | MEDLINE | ID: mdl-11222140

ABSTRACT

Ventral specification of mesoderm and ectoderm depends on signaling by members of the bone morphogenetic protein (Bmp) family. Bmp signals are transmitted by a complex of type I and type II serine/threonine kinase transmembrane receptors. Here, we show that Alk8, a novel member of the Alk1 subgroup of type I receptors, is disrupted in zebrafish lost-a-fin (laf) mutants. Two alk8/laf null alleles are described. In laf(tm110), a conserved extracellular cysteine residue is replaced by an arginine, while in laf(m100), Alk8 is prematurely terminated directly after the transmembrane domain. The zygotic effect of both mutations leads to dorsalization of intermediate strength. A much stronger dorsalization, similar to that of bmp2b/swirl and bmp7/snailhouse mutants, however, is obtained by inhibiting both maternally and zygotically supplied alk8 gene products with morpholino antisense oligonucleotides. The phenotype of laf mutants and alk8 morphants can be rescued by injected mRNA encoding Alk8 or the Bmp-regulated transcription factor Smad5, but not by mRNA encoding Bmp2b or Bmp7. Conversely, injected mRNA encoding a constitutively active version of Alk8 can rescue the strong dorsalization of bmp2b/swirl and bmp7/snailhouse mutants, whereas smad5/somitabun mutant embryos do not respond. Altogether, the data suggest that Alk8 acts as a Bmp2b/7 receptor upstream of Smad5.


Subject(s)
Body Patterning/physiology , Bone Morphogenetic Proteins/physiology , Embryo, Nonmammalian/physiology , Protein Serine-Threonine Kinases/physiology , Signal Transduction/physiology , Transforming Growth Factor beta , Zebrafish Proteins , Zebrafish/embryology , Activin Receptors , Animals , Bone Morphogenetic Protein 2 , Bone Morphogenetic Protein 7 , Cloning, Molecular , Crosses, Genetic , Genetic Linkage , Genotype , Mutagenesis , Phenotype , Phylogeny , Protein Serine-Threonine Kinases/genetics , Receptors, Transforming Growth Factor beta/genetics , Receptors, Transforming Growth Factor beta/physiology , Reverse Transcriptase Polymerase Chain Reaction , Transcription, Genetic , Zebrafish/genetics
19.
J Immunol ; 165(12): 6984-93, 2000 Dec 15.
Article in English | MEDLINE | ID: mdl-11120825

ABSTRACT

In the HLA, H2, and other mammalian MHC:, the class I and II loci are separated by the so-called class III region comprised of approximately 60 genes that are functionally and evolutionarily unrelated to the class I/II genes. To explore the origin of this island of unrelated loci in the middle of the MHC: 19 homologues of HLA class III genes, we identified 19 homologues of HLA class III genes as well as 21 additional non-class I/II HLA homologues in the zebrafish and mapped them by testing a panel of 94 zebrafish-hamster radiation hybrid cell lines. Six of the HLA class III and eight of the flanking homologues were found to be linked to the zebrafish class I (but not class II) loci in linkage group 19. The remaining homologous loci were found to be scattered over 14 zebrafish linkage groups. The linkage group 19 contains at least 25 genes (not counting the class I loci) that are also syntenic on human chromosome 6. This gene assembly presumably represents the pre-MHC: that existed before the class I/II genes arose. The pre-MHC: may not have contained the complement and other class III genes involved in immune response.


Subject(s)
Conserved Sequence , HLA Antigens/genetics , Major Histocompatibility Complex/genetics , Major Histocompatibility Complex/immunology , Radiation Hybrid Mapping/methods , Zebrafish/genetics , Zebrafish/immunology , Animals , Chromosome Mapping , Computational Biology/methods , Genetic Linkage/immunology , Humans , Phylogeny , Sequence Homology, Nucleic Acid
20.
Headache ; 40(8): 638-46, 2000 Sep.
Article in English | MEDLINE | ID: mdl-10971660

ABSTRACT

Vascular headaches, including migraine, cluster, and migrainous transformation to chronic daily headaches, are disabling. During and shortly after headache intervals, difficulties are reported in concentration, comprehension, and communication, not accounted for by nausea, photophobia, or sonophobia. These interfere with interpersonal relations and performance at work with economic loss. The hypothesis tested and reported here is that cognitive impairments comprise an important part of vascular headache diatheses. One hundred ninety-six otherwise normative subjects suffering from migraine or cluster, but not tension-type, headaches (136 women, 63 men; mean age, 46 years) participated in an outpatient prospective trial. One hundred thirty-three patients had migraine without aura, 39 migraine with aura, 11 periodic cluster (by IHS criteria), and 13 had migrainous transformation into chronic daily headaches. Neuropsychological testing was compared with and without headaches, by combined Mini-Mental Status Examination (MMSE), Cognitive Capacity Screening Examination (CCSE), and Hamilton Depression Rating Scale (HDRS). During headache intervals, significant decline was measured in both CCSE and MMSE scores (P <. 001) without HDRS change in all types of vascular headache and independent of headache severity, which often improved, or associated physical symptoms. Cognitive decline was promptly relieved by serotonin agonists and sleep. Disorders of cerebral serotoninergic projection systems appear to cause these reversible cognitive impairments.


Subject(s)
Cluster Headache/psychology , Cognition Disorders/etiology , Migraine Disorders/psychology , Adult , Aged , Female , Humans , Male , Mental Status Schedule , Middle Aged , Neuropsychological Tests
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