Real-world experience supporting the role of oncologic resection and adjuvant chemotherapy in biliary tract cancers

Background

Complete resection followed by adjuvant chemotherapy is the gold standard for patients with localized cholangiocarcinoma (CC) or gallbladder cancer (GBC). However, this is not always feasible, and recurrence rates remain high.

Objectives

To understand the real-world proportions and reason for treatment failure in resected biliary tract cancers.

Design and methods

We performed a retrospective population-based review of patients with GBC or CC [intrahepatic (IHCC) or extrahepatic (EHCC)] resected between 2005 and 2019 using the BC Cancer provincial database. A chart review was conducted to characterize demographics, treatments received and outcomes.

Results

In total, 594 patients were identified of whom 416 (70%) had disease recurrence. Most GBCs (96%) were diagnosed incidentally, and repeat oncologic resection was performed in 45%. Adjuvant chemotherapy was received in 51% of patients diagnosed after 2017 (mostly capecitabine). Patient co-morbidities, disease progression and patient preference were the commonest reasons for not proceeding with adjuvant chemotherapy. One-third of patients did not complete all planned cycles. Median overall survival was significantly higher in those with complete (R0) versus incomplete (R1) resection [31.6 versus 18 months, hazard ratio (HR): 0.43, 95% confidence interval (CI): 0.35-0.53] and in those with versus without re-resection for GBC [29.4 versus 19 months, HR: 0.55, 95% CI: 0.41-0.73]. There was a trend towards improved survival with versus without adjuvant therapy (HR: 0.79, 95% CI: 0.61-1.02). Only 25% in the more contemporary cohort (2017-2019) had an R0 resection and completed adjuvant chemotherapy.

Conclusion

Complete resection, including reresection for incidentally diagnosed GBCs, and adjuvant chemotherapy were associated with improved outcomes in this retrospective cohort, yet many patients were not able to complete these treatments. Neoadjuvant strategies may improve treatment delivery and ultimately, outcomes.

Neuropsychological assessment in pediatric epilepsy surgery: A French procedure consensus

Neuropsychological assessment is a mandatory part of the pre- and post-operative evaluation in pediatric epilepsy surgery. The neuropsychology task force of the ILAE - French Chapter aims to define a neuropsychological procedure consensus based on literature review and adapted for French practice. They performed a systematic review of the literature published between 1950 and 2023 on cognitive evaluation of individuals undergoing presurgical work-up and post-surgery follow-up and focused on the pediatric population aged 6-16. They classified publications listed in the PubMed database according to their level of scientific evidence. The systematic literature review revealed no study with high statistical power and only four studies using neuropsychological scales in their French version. Afterwards, the experts defined a neuropsychological consensus strategy in pediatric epilepsy surgery according to the psychometric determinants of cognitive tests, specificity of epilepsy, surgery context, French culture and literature reports. A common French neuropsychological procedure dedicated to pediatric epilepsy surgery is now available. This procedure could serve as a guide for the pre- and post-surgical work-up in French centers with pediatric epilepsy surgery programs. The main goal is to anticipate the functional risks of surgery, to support the postoperative outcome beyond the seizure-related one, while taking into consideration the plasticity and vulnerability of the immature brain and allowing the possibility of collaborative studies.

The contribution of inflammatory astrocytes to BBB impairments in a brain-chip model of Parkinson's disease

Astrocyte dysfunction has previously been linked to multiple neurodegenerative disorders including Parkinson's disease (PD). Among their many roles, astrocytes are mediators of the brain immune response, and astrocyte reactivity is a pathological feature of PD. They are also involved in the formation and maintenance of the blood-brain barrier (BBB), but barrier integrity is compromised in people with PD. This study focuses on an unexplored area of PD pathogenesis by characterizing the interplay between astrocytes, inflammation and BBB integrity, and by combining patient-derived induced pluripotent stem cells with microfluidic technologies to generate a 3D human BBB chip. Here we report that astrocytes derived from female donors harboring the PD-related LRRK2 G2019S mutation are pro-inflammatory and fail to support the formation of a functional capillary in vitro. We show that inhibition of MEK1/2 signaling attenuates the inflammatory profile of mutant astrocytes and rescues BBB formation, providing insights into mechanisms regulating barrier integrity in PD. Lastly, we confirm that vascular changes are also observed in the human postmortem substantia nigra of both males and females with PD.

Circulating tumor DNA in early-stage colon cancer: ready for prime time or needing refinement?

Liquid biopsies are the detection of molecular information in fluids from patients with cancer. In colorectal cancer (CRC), the most promising liquid biopsy strategy is the use of circulating tumor DNA (ctDNA) from plasma. In early-stage CRC, the potential for ctDNA to impact care stems from the detection of minimal residual disease (MRD) to guide adjuvant therapy after curative intent treatment and in identifying recurrences during surveillance. As for any new diagnostic test, ctDNA assays must overcome pre-analytical and analytical challenges before clinical implementation. We will discuss important logistical and assay considerations that clinicians and patients should understand when assessing ctDNA assays. We will also delve into important concepts to aid in interpreting ctDNA results and potential incidental findings that may arise. Sequencing errors, germline variants, and clonal hematopoiesis of indeterminate potential (CHIP) must be addressed to properly interpret results. CHIP is also an important consideration that impacts patient prognosis through association with cardiovascular and hematologic diseases. With this background in place, we next review the best available evidence for the use of ctDNA in early-stage colon cancer. Observational cohorts have established MRD after surgery as a significant prognostic factor for recurrence in stage II and III colon cancer. It also has the ability to anticipate clinical recurrence before standard investigations when used in surveillance. The first and only interventional randomized trial to date evaluating ctDNA is DYNAMIC. The study demonstrated the noninferiority of a MRD detection-guided approach in selecting patients with stage II colon cancer for adjuvant treatment. Notwithstanding the important results, there are still important questions to be answered before ctDNA enters prime time in the clinic. However, future appears bright and ongoing trials will help clarify how to best use this technology in early-stage colon cancer.

Patients' perspectives and safety of COVID-19 vaccination among cancer patients: A prospective single-center study

e24043

Background: Concerns about safety and treatment interference are known barriers to COVID-19 vaccination in cancer patients. Data on safety and tolerability in this population remain scarce. One of the objectives of this study is to describe COVID-19 vaccination safety in cancer patients. Methods: Patients diagnosed with a malignancy requiring systemic treatment in the last 12 months and undergoing COVID-19 vaccination were prospectively enrolled in this single-center study. Validated questionnaires to assess vaccine-related adverse events (VRAEs) were collected; chart review identified baseline characteristics and treatments received. Descriptive statistics and logistic regressions were performed. Results: 253 questionnaires were collected from 171 patients, enrolled between May and September 2021. 130 patients were survey-eligible after the 1st dose (D1) and 185 after 2nd dose (D2). 91 questionnaires were collected after D1 (Questionnaire 1: Q1) and 162 after D2 (Questionnaire 2: Q2). Surveys couldn’t be collected due to interval > 1 month between D1 / enrollment, patients’ unavailability, withdrawal of study or death. Median age was 55 (24-87) and 62.8% were female. 58.5% had solid tumors, treated with chemotherapy (49%) or checkpoint inhibitors only (9.5%); 19.4% malignancies were treated with targeted therapies and 22.1% had hematological malignancies. Most frequent solid tumors were breast (31.3%), lung (15.9%) and gastro-intestinal (GI) (14.3%). Patients received 45.6% Pfizer/BioNTech, 52.8% Moderna and 1.6% Oxford/AstraZeneca. A combination of 2 different vaccines was administered to 11.9%. Interval between D1 and D2 was ≤30 days in 53.1%, 31-90 days in 42.6%, and 91-180 days in 4.3%. Among all patients, 84.1% developed VRAEs after a median of 2 days post-vaccine for a median of 4 days. 74.5% had local symptoms (Sx) (pain, sensitivity and/or redness at injection site and/or arm) and 65.8% had systemic Sx. Most frequent systemic Sx were fatigue, chills or myalgia (39.4%), GI (6.3%) and fever (2.9%). Most patients (90.7%) described their Sx as having no / minimal impact (Gr 1), 7.8% reported seeking medical consultation (Gr 2), and 1.5% lead to hospitalization (Gr 3) (1 cardiovascular event, 1 infection; causality with concurrent systemic treatment not excluded and 1 due to malignancy). Gr 2, but not Gr 3, VRAEs were more common after D2 (11.4% vs 2.5%, p = 0.03). 41.7% considered their Sx as a new health problem. On multivariate analysis, younger age and female sex were significantly associated with the development of any Sx (OR 1.08, p = 0.01; OR 2.92, p = 0.02, respectively) and local Sx (OR 1.04, p = 0.04; OR 2.19, p = 0.04), but not systemic Sx or new health problem. Conclusions: Patients experienced mostly minor and transient symptoms post-vaccination; few perceived these as a new health problem. COVID-19 vaccination is overall safe and well-tolerated among cancer patients.

Transplant-ineligible newly diagnosed multiple myeloma: Current and future approaches to clinical care: A Young International Society of Geriatric Oncology Review Paper

Multiple myeloma is the second most common hematological malignancy in the USA and Europe. Despite improvements in the 5-year and overall survival rates over the past decade, older adults (aged ≥65 years) with multiple myeloma continue to experience disproportionately worse outcomes than their younger counterparts. These differences in outcomes arise from the increased prevalence of vulnerabilities such as medical comorbidities and frailty seen with advancing age that can influence treatment-delivery and tolerance and impact survival. In general, geriatric assessments can help identify those patients more likely to benefit from enhanced toxicity risk-prediction and aid treatment decision-making. Despite the observed benefits of geriatric assessments and other screening frailty tools, provider and systems-level barriers continue to influence the overall perception of the feasibility of geriatric assessments in clinical practice settings. Clinical trials are underway evaluating the efficacy and safety of various multiple myeloma therapies in less fit/frail older adults, with a minority examining fitness-based/risk-adapted approaches. Thus, significant gaps exist in knowing which myeloma therapies are most appropriate for older and more vulnerable adults with multiple myeloma. The purpose of this Review is to discuss how geriatric assessments can be used to guide the management of transplant-ineligible patients; and to highlight frontline therapies for standard-risk and high-risk cytogenetic abnormalities [i.e., t(4;14), t(14;16), and del(17p)] associated with multiple myeloma. We also discuss the current shortcomings of the existing clinical approaches to care and highlight ongoing clinical trials evaluating newer fitness-based approaches to managing transplant-ineligible patients.

Chicken adaptive response to low energy diet: main role of the hypothalamic lipid metabolism revealed by a phenotypic and multi-tissue transcriptomic approach

Background

Production conditions of layer chicken can vary in terms of temperature or diet energy content compared to the controlled environment where pure-bred selection is undertaken. The aim of this study was to better understand the long-term effects of a 15%-energy depleted diet on egg-production, energy homeostasis and metabolism via a multi-tissue transcriptomic analysis. Study was designed to compare effects of the nutritional intervention in two layer chicken lines divergently selected for residual feed intake.

Results

Chicken adapted to the diet in terms of production by significantly increasing their feed intake and decreasing their body weight and body fat composition, while their egg production was unchanged. No significant interaction was observed between diet and line for the production traits. The low energy diet had no effect on adipose tissue and liver transcriptomes. By contrast, the nutritional challenge affected the blood transcriptome and, more severely, the hypothalamus transcriptome which displayed 2700 differentially expressed genes. In this tissue, the low-energy diet lead to an over-expression of genes related to endocannabinoid signaling (CN1R, NAPE-PLD) and to the complement system, a part of the immune system, both known to regulate feed intake. Both mechanisms are associated to genes related polyunsaturated fatty acids synthesis (FADS1, ELOVL5 and FADS2), like the arachidonic acid, a precursor of anandamide, a key endocannabinoid, and of prostaglandins, that mediate the regulatory effects of the complement system. A possible regulatory role of NR1H3 (alias LXRα) has been associated to these transcriptional changes. The low-energy diet further affected brain plasticity-related genes involved in the cholesterol synthesis and in the synaptic activity, revealing a link between nutrition and brain plasticity. It upregulated genes related to protein synthesis, mitochondrial oxidative phosphorylation and fatty acid oxidation in the hypothalamus, suggesting reorganization in nutrient utilization and biological synthesis in this brain area.

Conclusions

We observed a complex transcriptome modulation in the hypothalamus of chicken in response to low-energy diet suggesting numerous changes in synaptic plasticity, endocannabinoid regulation, neurotransmission, lipid metabolism, mitochondrial activity and protein synthesis. This global transcriptomic reprogramming could explain the adaptive behavioral response (i.e. increase of feed intake) of the animals to the low-energy content of the diet.

French neuropsychological procedure consensus in epilepsy surgery

INTRODUCTION

Neuropsychological assessment is an integral component of the surgical procedure in patients with epilepsy. As no French consensus for neuropsychological assessment was available, the main goal of this work was to define French neuropsychological procedure consensus in regard to literature review.

METHOD

A panel of expert in neuropsychology was created within the framework of the French League Against Epilepsy. A systematic search of publications from 1950 to 2017 listed in PubMed database was conducted leading to a classification of articles according to their level of scientific evidence. French neuropsychological procedure consensus was then carried out with an expert panel of expert.

RESULTS

Low scientific evidence of neuropsychological data was reported. A panel of expert proposed a comprehensive neuropsychological assessment procedure including the exploration of intellectual efficiency, long-term memory, short-term and working memory, attention, executive functions, processing speed and motor skills, language, visual processing, praxis, psychobehavioral, and social cognition.

DISCUSSION

A common procedure for assessing cognitive and psychobehavioral function is now available in patients with epilepsy undergoing surgical evaluation have been established, they may help to improve the quality of care and the patient experience. This work highlights the need of furthers investigations and the necessity to develop specific tools with normative data.

[Identification of proteins associated with transcription factors HOXA9 and E2A-PBX1 by tandem affinity purification]

Chimeric transcription factor E2A-PBX1 induces the development of acute lymphoblastic B-cell leukemia in children. Using a transgenic mouse model, we previously demonstrated that homeobox (HOX) gene HOXA9 genetically interact with E2A-PBX1 gene in the development of B-cell leukemia in mice. HOXA9 itself is a potent oncogene resulting in myeloid leukemia when overexpressed, which is strongly accelerated by its collaborator Meis1. HOX, PBX1 and MEIS1 proteins have been shown to form hetero dimeric or trimeric complexes in different combinations. Cooperative interaction between PBX1 and HOX proteins enhances their DNA binding specificity, essential for HOX dependent developmental programs. PBX1 is retained in E2A-PBX1, and thus the strong transcriptional activator properties of E2A-PBX1 may lead to aberrant activation of normally repressed targets of HOX-PBX complexes. However, although there is evidence that E2A-PBX1 could bind to HOX and MEIS1 proteins it is still unclear whether such complexes are actually required for leukemic transformation or whether E2A-PBX1 and HOXA9 are each part of larger protein complexes acting in independent complementing oncogenic pathways. In this study we aim to search for other HOXA9 and E2A-PBX1 interacting proteins. To identify novel proteins interacting with human E2A-PBX1 or HOXA9 we used tandem affinity purification (TAP) of protein complexes from 697 pre-B leukemic and HeLa cell lines transduced to express E2A-PBX1 or HOXA9, respectively, with covalently attached FLAG/HA peptides. The protein composition of each complex was determined using tandem mass-spectrometry. In the E2A-PBX1 containing complex we identified lymphoid transcription factor IKAROS, chromatin remodeling factors of SWI/SNF family while multiple subunits of translation initiation factor eIF3, E3 ubiquitin ligase UBR5 emerged from the HOXA9 complex as potential critical protein partners. This is the first time the protein partners of either E2A-PBX1 or HOXA9 oncoproteins were identified using an unbiased biochemical approach. The identification of translation initiation factors associated with HOXA9 might indicate a novel function for HOX proteins independent of their transcriptional activity.

A metabolomic study reveals novel plasma lyso-Gb3 analogs as Fabry disease biomarkers

Fabry disease is an X-linked, multisystemic lysosomal storage disorder due to alpha-galactosidase A deficiency. It is characterized by the accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb(3)), in biological fluids, vascular endothelium, heart, and kidneys. Treatment by enzyme replacement therapy has been shown to be beneficial in both males and females affected with the disease. In addition to Gb(3), increased concentrations of globotriaosylsphingosine (lyso-Gb(3)) have recently been reported in urine and plasma of Fabry patients. The overall objective of this metabolomic study was to identify and characterize new potential plasma biomarkers in treated and untreated males and females affected with Fabry disease which might better reflect disease severity and progression. We employed a time-of-flight mass spectrometry metabolomic approach using plasma samples of Fabry patients compared to age-matched controls. We found three new lyso-Gb(3) analogs in Fabry patients presenting m/z ratios at 802, 804, and 820. As previously detected by our group, we also found a m/z ratio of 784 corresponding to the lyso-Gb(3) molecule minus two hydrogen atoms. Using exact mass measurements and tandem mass spectrometry, we confirmed that these analogs result from modifications of the lyso-Gb(3) sphingosine moiety. We evaluated the relative plasma concentration by measuring area counts for each lyso-Gb(3) analog. None of these analogs was detected in the majority of healthy controls. The relative concentration of each analog was higher in males compared to female Fabry patients. We demonstrated that mass spectrometry combined to a metabolomic approach is a powerful tool to detect and identify new potential biomarkers.

Novel gb(3) isoforms detected in urine of fabry disease patients: a metabolomic study

Fabry disease is characterized by the accumulation of globotriaosylsphingosine (lyso-Gb(3)) and globotriaosylceramide (Gb(3)) in biological fluids and tissues. Metabolomic studies recently undertaken by our group, showed the presence of novel plasma and urine lyso-Gb(3)-related analogs in male and female Fabry patients. These analogs are distinguished by differences in structure of the sphingosine moiety. The principal aim of this study was to evaluate the possibility of detecting other Fabry disease biomarkers structurally related to Gb(3). A time-of-flight mass spectrometry metabolomic approach, focusing on mass-to-charge (m/z) ratios from 1000 to 1200 Da, was devised. This m/z window corresponds to the isoforms and potential analogs of Gb(3). Five different categories of Gb(3)- related isoforms/analogs were detected: Gb(3)-related isoforms with saturated fatty acids, methylated Gb(3)-related isoforms, Gb(3)-related isoforms/analogs with one double bond, Gb(3) analogs with hydrated sphingosine, and Gb(3)-related isoforms/analogs with two double bonds. A secondary objective was to elucidate the relationship between Gb(3) and lyso-Gb(3). The methylation observed on Gb(3)-related analogs was not detected on lyso-Gb(3). We speculate that the methylated Gb(3) may be an intermediate compound in the deacylation of Gb(3) to generate the lyso-Gb(3) molecule. We are in the process of devising a quantification methodology for these methylated Gb(3)-related analogs in Fabry patients to try to understand the underlying biochemical mechanisms involved in this complex disease.

The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29Arp

In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial-fungal cell contact.

[Psychosocial adjustment after epilepsy surgical treatment]

Epilepsy is a matter of interest to several medical specialities: neurology, neurosurgery, pathology, psychiatry, and other fields of knowledge such as psychology and sociology. Although a high prevalence of psychopathological disorders is often reported among epileptic patients who are candidates for neurosurgery, this cannot explain the problems that may be experienced by patients after surgery. Numerous related aspects such as neurological, psychological and sociological factors cause disturbances. This study suggests that systematic psychological and social management might help in the transition from chronic disability to wellness by means of improved adjustment potential.

Validation of a solvent-free sampler for the determination of low molecular weight aliphatic isocyanates under thermal degradation conditions

During the thermal degradation of 1,6-hexamethylenediiso- cyanate-based (HDI) car paint, the eight most abundant isocyanates generated are isocyanic acid, methyl isocyanate, ethyl isocyanate, propyl isocyanate, butyl isocyanate, pentyl isocyanate, hexyl isocyanate, and 1,6-hexamethylenediisocyanate. For the first time, a method using solvent-free samplers is proposed and validated for the simultaneous sampling of all these isocyanates. The sampling efficiency during thermal degradation of car paint can be affected by the formation of dust and aerosols and by the emission of many chemicals, such as isocyanic acid, anhydrides, amines, and alcohols that consume the reagent or interfere in the derivatization procedure. Sampling was performed using cassettes containing two 1-(2-methoxyphenyl)piperazine (MOPIP)-coated glass fiber filters (MFs) (approximately 4.9 mg per filter) and compared with bubblers containing 15 mL of MOPIP solution in toluene (1.0 mg/mL(-1)) and with bubblers backed with MFs. A DIN 53436 laboratory scale furnace was used to generate the isocyanates under thermal degradation conditions. For an aliphatic isocyanate concentration of approximately 42 microg(NCO) m(-3), no significant difference in sampling efficiency was observed between the three techniques studied, thus confirming the sampling efficiency of the MFs. The samples were analyzed using high-performance liquid chromatography coupled with electrospray/tandem mass spectrometry. Quantification was performed in daughter mode monitoring (MOPIP+H)(+) fragments. For concentrations between 0.013 microg(NCO) mL(-1) and 0.52 microg(NCO) mL(-1) for the monoisocyanates, and between 0.026 microg(NCO) mL(-1) and 1.04 microg(NCO) mL(-1) for the HDI, the correlation coefficients were in the 0.9974-0.9996 range (n = 18). Analytical reproducibility and precision were better than 95.4% and 94.9%, respectively, for all the isocyanates. The instrumental detection limits, defined as three times the standard deviation measured at the lowest point on the calibration curve were in the 1.8-3.0 ng(NCO) mL(-1) range (n = 8), which corresponds to about 0.37-0.60 microg(NCO) m(-3) for a 15-L air sample when the filters are desorbed in 3 mL.

Temperature-programmed pyrolysis hyphenated with metastable atom bombardment ionization mass spectrometry (TPPy/MAB-MS) for the identification of additives in polymers

Thermoanalytical techniques are currently used for the analysis of additives contained in polymers that cannot be easily dissolved, extracted, or hydrolyzed. With these techniques, the polymers are heated to liberate the additives trapped in the polymer matrix. If the polymer is heated slowly, up to its thermal degradation, the technique is called temperature-programmed pyrolysis (TPPy). For TPPy experiments, mass spectrometry is generally used as the detection method. The ionization sources commonly used in mass spectrometry, such as CI and EI, can cause fragmentation during the ionization process. Fragmentation decreases the sensitivity of the molecular ions and increases the risks of interferences with the compounds coming from the matrix. An energy-tunable ionization technique, called metastable atom bombardment (MAB), is proposed for TPPy/MS experiments. With this ionization source, the energy of ionization depends on the metastable gas used. With low-energy metastable gases such as Xe or N(2), fragmentation is reduced compared to CI, whereas with medium-energy metastable gases such as Ar or Kr, the fragmentation is similar to that observed with CI. TPPy/MAB-MS was performed on an unknown polyurethane-based car paint. The detection of molecular ions and characteristic fragments with MAB(N(2)) led to the identification of two light stabilizers: Bis(1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate (BPPS) and 2-(2H-benzotriazol-2-yl)-4,6- di-tert-pentylphenol (PTPP). Using MAB(Ar) to simulate CI, the molecular ion and one of the two characteristic fragments of BPPS were not detected, thus confirming the advantage of using MAB(N(2)) ionization for TPPy/MS experiments.

Host-based divergence in populations of the pea aphid: insights from nuclear markers and the prevalence of facultative symbionts

In North America, the pea aphid Acyrthosiphon pisum encompasses ecologically and genetically distinct host races that offer an ideal biological system for studies on sympatric speciation. In addition to its obligate symbiont Buchnera, pea aphids harbour several facultative and phylogenetically distant symbionts. We explored the relationships between host races of A. pisum and their symbiotic microbiota to gain insights into the historical process of ecological specialization and symbiotic acquisition in this aphid. We used allozyme and microsatellite markers to analyse the extent of genetic differentiation between populations of A. pisum on pea, alfalfa and clover in France. In parallel, we examined: (i) the distribution of four facultative symbionts; and (ii) the genetic variation in the Buchnera genome across host-associated populations of A. pisum. Our study clearly demonstrates that populations of A. pisum on pea, clover and alfalfa in France are genetically divergent, which indicates that they constitute distinct host races. We also found a very strong association between host races of A. pisum and their symbiotic microbiota. We stress the need for phylogeographic studies to shed light on the process of host-race formation and acquisition of facultative symbionts in A. pisum. We also question the effects of these symbionts on aphid host fitness, including their role in adaptation to a host plant.

A sex-linked locus controls wing polymorphism in males of the pea aphid, Acyrthosiphon pisum (Harris)

Discrete variation in wing morphology is a very common phenomenon in insects and has been used extensively in the past 50 years as a model to study the ecology and evolution of dispersal. Wing morph determination can be purely genetic, purely environmental, or some combination of the two. The precise genetic determinants of genetically based wing morph variation are unknown. Here we explore the genetic basis of wing polymorphism in the pea aphid, which can produce either winged or wingless males. We confirm that three types of pea aphid clones coexist in natural populations, those producing winged males only, those producing wingless males only, and those producing a mixture of both. A Mendelian genetic analysis reveals that male wing polymorphism in pea aphids is determined by a single locus, two alleles system. Using microsatellite loci of known location, we show that this locus is on the X chromosome. The existence of a simple genetic determinism for wing polymorphism in a system in which genetic investigation is possible may help investigations on the physiological and molecular mechanisms of genetically-based wing morph variation. This locus could also be used in the search for genes involved in the wing polyphenism described in parthenogenetic females and to investigate the interplay between polymorphisms and polyphenisms.

Bovine coronaviruses associated with enteric and respiratory diseases in Canadian dairy cattle display different reactivities to anti-HE monoclonal antibodies and distinct amino acid changes in their HE, S and ns4.9 protein

Bovine coronavirus isolates associated with recent outbreaks of respiratory disease in Ontario and Quebec dairy farms were compared to reference strains known to be responsible for neonatal calf diarrhea (NCD) or winter dysentery (WD) of adult cattle. In respect to their hemagglutinating properties and their higher RDE activities with rat erythrocytes, WDBCoV strains differed from NCDBCoV strains and respiratory bovine coronaviruses RBCoV strains. Serologically, three MAbs directed to the HE glycoprotein of the WDBCoV strain BCQ.2590 recognized two serogroups amongst NCDBCoV strains by hemagglutination inhibition, whereas only one of the MAbs failed to react toward three of the four RBCoV isolates tested. Sequencing analysis of the S (S1 portion), HE, ORF4 and ORF5 genes of BCoV isolates associated with different clinical syndromes indicated that neither insertions or deletions could explain their distinct tropism. For the HE glycoprotein, a total of 15 amino acids (aa) substitutions were identified by comparing field isolates to the prototype Mebus strain. Two specific proline substitutions were identified for virulent strains being located in the signal peptides (aa 5) and aa position 367; one specific aa change was revealed at position 66 for RBCoV field isolates. Analysis of the S1 portion of the S glycoprotein revealed a total of eight aa changes specific to enteropathogenic (EBCoV) strains and eight aa changes specific to RBCoV strains. For all BCoV isolates studied, the region located between the S and M genes (ORF4) apparently encodes for two non-structural (ns) proteins of 4.9 and 4.8 kDa. A specific non-sense mutation was identified for the nucleotide at position 88 of the putative 4.9 kDa protein gene of RBCoV isolates resulting in 29 rather that 43 aa residues. The ORF5, which encodes a 12.7 ns protein and the 9.5 kDa E protein, was highly conserved amongst the BCoV field isolates.

Decreased amounts of antibodies to 22 and 18 kDa antigens in the peritoneal fluid of patients with endometriosis. LE Group d'Investigation en Gynecologie

Accumulated evidence implicates immunological alterations in endometriosis. The purpose of this study was to look for variations in antibodies to distinct antigens in peritoneal fluid of women with and without endometriosis. Peritoneal fluid was aspirated from 17 women undergoing laparoscopy for tubal ligation and 37 patients complaining of symptoms of pain and /or infertility. Peritoneal fluid antibodies to a standard preparation of peritoneal fluid antigens were detected by Western blot analysis using peroxidase-labelled anti-human immunoglobulin G antibodies specific to the Fc region. Antibodies to distinct antigens were quantified by estimating the ratio of the relative optical density between samples and a standard amount of antibodies. Marked changes were found in the antibody detection to two antigens having apparent molecular weights of 22 and 18 kDa. The intensity of the antibody signal was significantly weaker in the peritoneal fluid from endometriosis patients (0.36 +/- 0.06 and 0.46 +/- 0.06) compared with that in women without endometriosis (0.62 +/- 0.08 and 0.75 +/- 0.06). It was also weaker in patients without endometriosis presenting with infertility (0.36 +/- 0.07 and 0.47 +/- 0.08), but only the 18 kDa antigen result was significant. After adjusting for infertility, the P values for the 18 and 22 kDa bands were 0.03 and 0.28 (not significant) respectively in the group of endometriosis patients. These changes were not related to the phase of the menstrual cycle. These data suggest an alteration in the immune response to two distinct antigens in the peritoneal fluid from women with endometriosis and infertility. Further evaluation of these two antigens and their antibodies would be of interest to help understand endometriosis and its associated infertility.

Effects of SR 49059, a non-peptide antagonist of vasopressin V1a receptors, on vasopressin-induced coronary vasoconstriction in conscious rabbits

The effect of SR 49059, a new potent non-peptide vasopressin (AVP) V1a receptor antagonist, was investigated on AVP-induced electrocardiogram modifications. A high intravenous dose of AVP (0.5 IU or 1.23 micrograms/animal) produced an important transient t-wave elevation (from 4.7 +/- 0.2 to 8.9 +/- 0.7 mm) and heart rate decrease (from 199 +/- 5 to 99 +/- 6 bpm) in conscious rabbits. The t-wave increase was a significant index of coronary vasoconstriction-induced cardiac ischemia. SR 49059 had potent protective effects in this model both by intravenous (0.125 to 0.5 mg/kg) and oral (2.5 to 10 mg/kg) routes. After a 30-min pre-treatment, SR 49059 showed dose-dependent protection on t-wave elevation and heart rate decrease with ED50's of 95 (95% CL:168-22) and 30 (95% CL:54-6) micrograms/kg i.v., respectively. Complete blockade occurred with doses of 2 mg/kg i.v. and upwards. By the oral route, SR 49059 was rapidly absorbed and a dose of 10 mg/kg displayed a protective effect lasting more than 6 hours on both electrocardiogram parameters. Moreover, SR 49059 exerted a high stereospecific inhibitory effect since its enantiomer was totally inactive at 0.5 mg/kg i.v., suggesting that protection occurred by interaction with vascular AVP V1a receptors. Thus, SR 49059 is the first specific non-peptide V1a antagonist with long-lasting oral activity on AVP-induced coronary vasoconstriction and bradycardia. With this original profile, SR 49059 could be a promising therapeutical antivasospastic agent for preventing AVP-induced cardiac damage.

Importance of the phenotypic state of vascular smooth muscle cells on the binding and the mitogenic activity of endothelin

Smooth muscle cells of the rabbit aorta, when grown in vitro, express distinguishable forms of phenotypes (contractile and synthetic). On contractile cells, ET-1 specifically bound to a single class of high affinity (KD = 128 pM) and high capacity (Bmax = 66,000 sites/cell) binding sites. But, whereas affinity of [125I]-ET-1 was not significantly affected by phenotypic modulation, synthetic cells displayed a 10-fold lower [125I]-ET-1 binding capacity than contractile smooth muscle cells. Similarly, the mitogenic effect of ET-1 on smooth muscle cells was considerably lower for synthetic than for contractile cells. The ET-1 receptor on primary cells was recognized by sarafotoxin S6b and the different ET-related peptides with an order of potency [ET-1 greater than S6b greater than ET-3 greater than Big ET-1 much greater than ET(16-21)] identical to that inducing smooth muscle cell growth. Therefore, these data indicate that the binding and the mitogenic effects of ET-1 on smooth muscle cells might be of different magnitudes depending on the phenotypic state of these cells.