Grambank reveals the importance of genealogical constraints on linguistic diversity and highlights the impact of language loss

While global patterns of human genetic diversity are increasingly well characterized, the diversity of human languages remains less systematically described. Here, we outline the Grambank database. With over 400,000 data points and 2400 languages, Grambank is the largest comparative grammatical database available. The comprehensiveness of Grambank allows us to quantify the relative effects of genealogical inheritance and geographic proximity on the structural diversity of the world's languages, evaluate constraints on linguistic diversity, and identify the world's most unusual languages. An analysis of the consequences of language loss reveals that the reduction in diversity will be strikingly uneven across the major linguistic regions of the world. Without sustained efforts to document and revitalize endangered languages, our linguistic window into human history, cognition, and culture will be seriously fragmented.

Identifying barriers to care for complex airway disease and multidisciplinary solutions to optimize therapy in Canada

Background

Complex airway disease such as Chronic Rhinosinusitis with Asthma or Aspirin Exacerbated Respiratory Disease requires a multidisciplinary approach to management and treatment. Many centers in the USA have created collaborative multidisciplinary clinics to support the management of these patients; however, similar structures do not appear to exist in Canada.

Methods

This mixed methods study used a combination of structured interviews and a cross-sectional national survey. Interviewees included members of the Canadian Rhinology Working Group and survey participants were a combination of academic and community Rhinologists, Respirologists and Allergists. All participation was voluntary and selection criteria was based on their involvement in treating complex airway disease. Our objective was to identify the current state of diagnosis and treatment of complex airway patients in Canada between Rhinology, Respirology and Allergy and understand the barriers, challenges and propose solutions to establishing a multidisciplinary airway clinic in Canada.

Results

Four Rhinologists participated in qualitative interviews and a convenience sample of 42 specialists through our known network responded to our quantitative survey. From our survey, 54.8% believed multidisciplinary clinics were necessary in the management of complex airway disease, providing better outcomes and cost-savings (69%, 45.2%). Most specialties agreed that history, physical, pulmonary function and skin prick testing was important for diagnosis (92.9%, 92.9%, 88.1%). If clinicians were to participate in a multidisciplinary clinic, they would be willing to forego an average of 14.2% of their mean daily income for that clinic. The ideal clinic location was split between a neutral shared location vs. a Rhinology clinic space (38.1%, 45.2%).

Conclusions

Complex airway diseases are currently managed in subspecialty silos resulting in fragmented care. Our study highlights gaps in management, areas for improvement and support for establishing multidisciplinary complex airway disease clinics in Canada to better treat this population.

The importance of both CYP2C19 and CYP2B6 germline variations in cyclophosphamide pharmacokinetics and clinical outcomes

Cyclophosphamide is an alkylating agent used in the treatment of solid and haematological malignancies and as an immunosuppressive agent. As a prodrug, it is dependent on bioactivation to the active phosphoramide mustard metabolite to elicit its therapeutic effect. This focused review will highlight the evidence for the role of germline pharmacogenetic variation in both plasma pharmacokinetics and clinical outcomes. There is a substantial indication from 13 pharmacokinetic and 17 therapeutic outcome studies, in contexts as diverse as haematological malignancy, breast cancer, systemic lupus erythematosus and myeloablation, that pharmacogenetic variation in both CYP2C19 and CYP2B6 influence the bioactivation of cyclophosphamide. An additional role for pharmacogenetic variation in ALDH1A1 has also been reported. Future studies should comprehensively assess these 3 pharmacogenes and undertake appropriate statistical analysis of gene-gene interactions to confirm these findings and may allow personalised treatment regimens.

Myocardial perfusion/metabolism mismatch and ventricular arrhythmias in the chronic post infarction state

Aim: Ventricular arrhythmias have been shown to originate in the myocardial peri-infarct region due to irregular heterotopic conduction. Hypoperfused but viable myocardium is often localised in those areas and may be involved in the pathogenesis of arrhythmias. We tested the hypothesis that these myocardial perfusion/metabolism mismatches (MM) are significantly associated with ventricular arrhythmias in the chronic post infarction state. Patients, methods: 47 post infarction patients were included in the study. 33 suffered from ventricular arrhythmia whereas 14 did not. All patients underwent 99mTc tetrofosmin SPECT and 18F-FDG PET. A region-of-interest(ROI)-analysis was used to assess viable myocardium based on predefined MM-criteria. Univariate analyses as well as a logistic regression model for the multivariate analysis were carried out. Results: 94% of the arrhythmic patients displayed at least one MM-segment as compared to 64% of the non-arrhythmic patients. MMsegments and arrhythmia showed a statistically significant relation (p = 0.018). The logistic regression model predicted the occurrence or absence of arrhythmia in 85% of all cases. Multivariate analysis gave consistent results, after adjusting for symptomatic chronic heart failure (CHF), aneurysms and age. Conclusion: Our results support the hypothesis that hypoperfused but viable myocardium represents an arrhythmogenic substrate and is a relevant risk factor for developing ventricular arrhythmias following myocardial infarction. Therefore, the detection of MM-segments allows the identification of patients with a higher risk for future cardiac events.

Expression and significance of ERβ and TrkB in endometriosis

OBJECTIVES

To study the potential pathogenesis of endometriosis (EMs) in an area of estrogen receptors (ERs) and tyrosine kinase receptor type B (TrkB) expressions in tissues from patients with EMs.

STUDY DESIGN

The authors examined the expressions of ERα, ERβ, TrkB, brain-derived neurotrophic factor (BDNF), and SGPL1 in tissues with EMs, using real-time PCR, western blot, and immunohistochemistry.

RESULTS

ERα and SGPL1 were mainly expressed in eutopic endometrium than that in ectopic endometrium of patients with ovarian endometriosis (p < 0.05), while ERβ, BDNF, and TrkB were adverse, mainly detected in ectopic endometrium of the same patients with EMs (p < 0.01 and p < 0.05 ) by real-time PCR and western blot. ERβ, ERα, TrkB, and SGPL1 proteins were mainly expressed in eutopic endometrium of proliferative phase with EMs than that in eutopic endometrium of secretory phase (p < 0.05 ). TrkB, BDNF, and SGPL1 were not found in endometrium of proliferative or secretory phase in control group.

CONCLUSIONS

ERβ expressed in cytoplasm may mediate pathogenesis of EMs.

Imiquimod use in adolescents: off-label but effective

Genital warts are very common in the under-18 years old population, yet treatment with imiquimod is currently off-label. We looked at 50 cases of genital warts in patients aged under 18 years who had been treated with Imiquimod to see if this treatment was effective, and it was.

P4-11-19: Healthcare Resource Utilization among Breast Cancer Patients with Bone Metastases and Skeletal-Related Events: A Population-Based Cohort Study in Denmark (1997 - 2009)

Background

The healthcare resource utilization (HRU) of breast cancer patients who develop bone metastases and skeletal-related events (SREs) has not been well-characterized. Our objective was to describe the HRU associated with SREs in a large population-based cohort of Danish breast cancer patients with bone metastases and one or more SRE.

Methods: We identified women diagnosed with incident breast cancer from January 1, 1997 through December 31, 2006 using the Danish Cancer Registry. We followed this cohort of patients for development of subsequent bone metastases and SREs identified through the Danish National Registry of Patients through December 31, 2009. SREs were defined as pathologic fracture, spinal cord compression, and radiation or surgery to bone. Among patients with only one SRE, the HRU period, composed of all HRU occurring within a 90-day period after the SRE and within a two-week diagnostic period prior to the SRE, was assessed. For patients with multiple SREs (each one separated by less than 90 days), the HRU period, composed of all HRU occurring within a two-week diagnostic period prior to the first SRE up until 90 days after the last SRE, was described. Patients may have had multiple HRU periods if SREs were separated by more than 90 days. The HRU summarized included number of inpatient hospitalizations, length of hospitalization stay, outpatient physician visits, emergency room visits, and procedures.

Results: We identified 1,148 patients with bone metastases and SREs among 38,485 breast cancer patients. The mean age at breast cancer diagnosis for those who developed bone metastases and SREs was 59 years (SD, 13 years) and the majority (72%) of patients had multiple SREs during the first HRU period. Approximately 20% to 30% of patients with single and multiple SREs, respectively, died within the first HRU period. Overall, length of hospitalization was longest for patients with spinal cord compression followed by patients with pathologic fracture. In general, patients with multiple SREs had higher HRU compared to those with a single SRE in the first HRU period, particularly in length of hospitalization stay.

Conclusion: SREs secondary to bone metastases are serious events. In Denmark, high HRU was observed in all patients with SREs, but especially in those with multiple SREs, where increased lengths of hospitalization were observed.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-11-19.

Ministry of Health clinical practice guidelines: bipolar disorder

The Ministry of Health (MOH) has published clinical practice guidelines on Bipolar Disorder to provide doctors and patients in Singapore with evidence-based guidance on the management of bipolar disorders. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Bipolar Disorder, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website: http: //www.moh.gov.sg/content/moh_web/home/Publications/guidelines/clinical_practiceguidelines/2011/bipolar_disorder.html. The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.

Mortality following bone metastasis and skeletal-related events among men with prostate cancer: a population-based analysis of US Medicare beneficiaries, 1999-2006

Information on the impact of bone metastasis and skeletal-related events (SREs) on mortality among prostate cancer patients is limited. Using the linked Surveillance, Epidemiology and End Results (SEER)-Medicare database, we identified men aged 65 years or older diagnosed with prostate cancer between July 1 1999 and December 31 2005 and followed to determine deaths through December 31 2006. We classified subjects as having bone metastasis and SREs as indicated by Medicare claims. Using Cox regression, we estimated mortality hazards ratios (HR) among men with bone metastasis with or without SRE, compared with men without bone metastasis. Among 126,978 men with prostate cancer (median follow-up, 3.3 years), 9746 (7.7%) had bone metastasis at prostate cancer diagnosis (1.7%) or during follow-up (5.9%). SREs occurred in 4296 (44%) men with bone metastasis. HRs for risk of death were 6.6 (95% CI=6.4-6.9) and 10.2 (95% CI=9.8-10.7), respectively, for men with bone metastasis but no SRE and for men with bone metastasis plus SRE, compared with men without bone metastasis. Bone metastasis was associated with mortality among prostate cancer patients. This association appeared to be stronger for bone metastasis plus SRE than for bone metastasis without SRE.

Intratumor RNA interference of cell cycle genes slows down tumor progression

Small interfering RNAs (siRNAs) are emerging as promising therapeutic tools. However, the widespread clinical application of such molecules as modulators of gene expression is still dependent on several aspects that limit their bioavailability. One of the most promising strategies to overcome the barriers faced by gene silencing molecules involves the use of lipid-based nanoparticles (LNPs) and viral vectors, such as adenoviruses (Ads). The primary obstacle for translating gene silencing technology from an effective research tool into a feasible therapeutic strategy remains its efficient delivery to the targeted cell type in vivo. In this study, we tested the capability of LNPs and Ad to transduce and treat locally tumors in vivo. Efficient knockdown of a surrogate reporter (luciferase) and therapeutic target genes such as the kinesin spindle protein (KIF11) and polo-like kinase 1 were observed. Most importantly, this activity led to a cell cycle block as a consequence and slowed down tumor progression in tumor-bearing animals. Our data indicate that it is possible to achieve tumor transduction with si/short hairpin RNAs and further improve the delivery strategy that likely in the future will lead to the ideal non-viral particle for targeted cancer gene silencing.

Diabetes and genital warts: an unhappy coalition

Through clinical practice, it is often perceived that patients with diabetes are more likely to suffer from severe and recalcitrant warts. This study was set up to investigate if genital warts were more common in patients with diabetes and to determine if patients with diabetes and genital warts required more treatment than those without diabetes. Only female patients with diabetes and genital warts were investigated and were compared to the non-diabetic population. Results suggested that patients with diabetes had more extensive warts and recurrences. This study will hopefully further inform the debate surrounding preferential use of quadrivalent human papilloma virus (HPV) vaccine as opposed to bivalent HPV vaccine especially in the setting of a Diabetes Young Person's clinic.

Impact of an occupational health promotion program on subsequent illness and mortality experience

BACKGROUND

Integrating general health initiatives into established occupational health programs may be an effective way of contributing more broadly to employee health. Objective assessment of the success of such initiatives is needed, but is often difficult to carry out because of their voluntary nature.

METHODS

A cohort of 24,586 wage employees, 35+ years of age and with 15+ years of prior employment, was established to assess morbidity and mortality outcomes relative to participation in an ongoing health initiative instituted in 1983. Outcomes were evaluated for employees who attended the seminar program (attendees), those who had clearance examinations, but did not take part in the program (withdrawals), and non-participants.

RESULTS

At entry to follow-up, the prevalence of chronic illnesses including diabetes, obesity, and diseases of the circulatory system was lowest among non-participants and highest among withdrawals. During the follow-up period, the incidence of new disease conditions was similar between attendees and non-participants; however, overall mortality was significantly reduced among attendees after adjustment for explanatory factors including age, job grade, smoking history, alcohol intake, and body-mass-index (relative risk = 0.83; 95% confidence interval: 0.69-0.99) and was still marginally decreased when withdrawals were combined with attendees.

CONCLUSIONS

Although self-selection cannot be ruled out as a contributing factor to the reduction in mortality risk among attendees, our findings indicate that offering health promotion activities in the context of an existing occupational health program may benefit overall employee health.

The Incidence of Bone Metastases and Skeletal-Related Events in Breast Cancer Patients: A Population-Based Cohort Study in Denmark (1999 – 2007)

Background Breast cancer (BrCa) is the most commonly diagnosed cancer among women in the industrialized world. More than half of women presenting with metastatic BrCa develop bone metastases. Bone metastases increase the risk of skeletal-related events (SREs), defined as radiation to bone, pathologic fractures, spinal cord compression, bone surgery, or altered antineoplastic therapy to treat bone pain. Both bone metastases and SREs are associated with unfavorable prognosis and greatly affect quality of life. To date, the epidemiology of the subgroup of BrCa patients who develop bone metastases and/or SREs has not been well-characterized. Our objective was to estimate the one- and five-year incidence of bone metastases and SREs in a large population cohort of newly-diagnosed BrCa patients in Denmark (population ∼ 5.4 million inhabitants). Methods We identified women diagnosed with BrCa (International Classification of Diseases, 10th Revision (ICD-10) code C50.x.) from January 1, 1999 through December 31, 2007, with follow-up through April 2008. We retrieved this data from Denmark's National Registry of Patients (NRP), which includes records from all Danish hospitals. We also identified bone metastases (ICD-10 code C79.5) and recorded SREs. The Kaplan-Meier method was used to estimate time to bone metastases and time to first SRE. We also calculated 1- and 5-year incidence rates (IR) of bone metastases and first SRE in newly-diagnosed BrCa patients. Results We identified 35,941 BrCa patients from the NRP. The median age at diagnosis was 62 years (range, 18-104 years). A total of 1,494 (4%) patients developed bone metastases during follow-up, and of these, 712 developed an SRE. The distribution of SREs by type were 394 (55%) with radiation to the bone, 133 (19%) with pathological or osteoporotic fracture, 42 (6%) with bone surgery, and 143 (20%) with spinal cord compression. The 1-year IR of bone metastases was 13.7 [95% confidence interval (CI): 12.5-15.0] per 1000 person-years (P-Y). The 1-year IR of SREs among patients with bone metastases was 55 times that of the 1-year IR of bone metastases in BrCa patients at 759.2 (95% CI: 662.0-870.5) per 1000 P-Y. After five years of follow-up, the incidence curves plateaued at approximately 4% and 48% for bone metastases and SREs, respectively (Figures 1 and 2). Conclusions Among breast cancer patients with bone metastases, there was a strong tendency towards development of SREs within a year of bone metastases diagnosis; however, this phenomenon stabilized beyond 5 years of bone metastases diagnosis.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2051.

Data standards for minimum information collection for antibody therapy experiments

Research groups developing antibody therapies generate diverse data sets; the value of these sets would be compounded when shared or amalgamated. A complete amalgamation of diverse data sets requires data standards for information collection during experiments. We propose to define elements of the data standards in the form of common data elements (CDEs) in order to clarify each experiment's targets and data values. We have created a set of core information elements which we suggest should be collected from antibody therapy experiments. We propose these as a basis for community consultation with a view to defining a set of data standards which can be developed under the auspices of the Antibody Society.

Survival associated with bone metastases and skeletal-related events in breast cancer patients: A population-based cohort study in Denmark (1999 - 2007)

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Background: Breast cancer (BrCa) is the most commonly diagnosed cancer for women in the industrialized world. Among women who present with metastatic BrCa, more than half will develop bone metastases. Bone metastases increase the risk for skeletal-related events (SREs) defined as radiation to bone, pathologic fractures, spinal cord compression, surgery to bone, or change in antineoplastic therapy to treat bone pain. These complications are associated with an unfavorable prognosis and have a major impact on patients' quality of life. However, data on survival of BrCa patients who experience SREs are lacking. We evaluated survival among BrCa patients without bone metastases, with bone metastases, and with both bone metastases and SREs. Methods: Using Denmark's National Registry of Patients (NRP) database, we conducted a retrospective cohort study in the North and Mid- Jutland Region. Patients with a diagnosis of BrCa from January 1, 1999 through December 31, 2007 were identified using the International Classification of Diseases, 10th Revision (ICD-10) codes C50.x. SREs after BrCa diagnosis were identified using the ICD-10 code C79.5. Cox proportional-hazards regression was used to estimate the mortality rate ratio (MRR), adjusting for age and comorbidity, to compare survival among three subgroups of BrCa patients: no bone metastases, bone metastases, and bone metastases with SREs. Results: We identified 9,474 BrCa patients from the NRP. Of these, 621 (7%) developed bone metastases and 267 (3%) developed both bone metastases and SREs during the study period. The 5-year mortality rates among BrCa patients without bone metastases, with bone metastases, and with bone metastases and SREs were 50.7 per 1,000 person-years (PYs), 469 per 1,000 PYs, and 712 per 1,000 PYs, respectively. Compared to BrCa patients without bone metastases, the adjusted MRRs among BrCa patients with bone metastases and patients with bone metastases and SREs were 11.6 [95% confidence interval (CI): 10.9 - 13.6] and 18.1 (95% CI: 15.5 - 21.0), respectively. Conclusions: Our results suggest that bone metastases and SREs have a major impact on the overall mortality of BrCa patients in Denmark.

[Table: see text]

Prevalence of early-stage prostate and estrogen receptor positive (ER+) breast cancer patients receiving primary androgen deprivation therapy (ADT) and aromatase inhibitors (AIs) in the United States (U.S.)

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Background: AIs and ADT are used to prevent recurrence of breast and prostate cancers but have been shown to accelerate bone loss. We estimated the prevalence of early-stage ER+ breast and prostate cancer patients on hormone therapy in the U.S., as this is not well-described in the literature. Methods: Data from the Surveillance, Epidemiology, and End Results (SEER) Program, published literature, clinical practice, and a large claims database were used. We began with the American Cancer Society's estimated number of new breast and prostate cancer cases for the year 2008. We then assessed the number of patients with localized/regional disease and ER+ tumors and those receiving primary ADT (both chemical and surgical) or AI therapy by applying proportions from SEER, published literature, clinical practice, and the claims database. Using these incident case counts, we calculated the 5-year prevalence using appropriate cohort-specific survival rates to sum the number of new and surviving cases over a 5-year period. Results: The estimated 5-year prevalence of early-stage ER+ breast cancer for women aged ≥50 years in the U.S. was 607,411, of which 293,904 (48.4%) were on AI therapy based on the claims database. However, because this data source was limited to women aged <65 years, we also used estimates from clinical practice to capture AI use for women of all ages. Based on clinical practice, 402,637 (66.3%) to 460,156 (75.8%) of early-stage ER+ breast cancer patients were on AI therapy. For early-stage prostate cancer, the estimated 5-year prevalence for all ages was 1,024,238, of which 141,451 (13.8%) were on primary ADT. However, these figures may underestimate current usage of hormone therapies, as our data and the literature show increasing trends in ADT and AI use for early-stage disease. Conclusions: Based on a combination of population-based data and the published literature, approximately half of all early-stage ER+ breast cancer patients and a modest proportion of early-stage prostate cancer patients are on hormone therapy in the U.S.

[Table: see text]

Intra-arterial nimodipine for severe cerebral vasospasm after aneurysmal subarachnoid hemorrhage: influence on clinical course and cerebral perfusion

BACKGROUND AND PURPOSE

The efficacy of intra-arterial administration of nimodipine (IAN) in patients with severe vasospasm after aneurysmal subarachnoid hemorrhage (SAH) remains unproved. The goal of the present study was to investigate the clinical effect and cerebral perfusion after IAN in patients with severe vasospasm refractory to hemodynamic treatment.

MATERIALS AND METHODS

Twenty-six of 214 patients with aneurysmal SAH were included in the prospective study, approved by the local ethics committee. All patients met the criteria of medically refractory cerebral vasospasm. Effectiveness was monitored angiographically by digital subtraction angiography and by transcranial Doppler (TCD), perfusion CT (PCT), and neurologic examination during treatment course and follow-up.

RESULTS

No angiographic effect was observed in 8 patients. The pooled PCT values revealed a reduction of time to peak (P = .03) and mean transit time (P = .17) 1 day after intervention. This effect did not persist during the following days. The pooled TCD analysis demonstrated a transient increase in flow 1 day after intervention (P = .03). No trend was evident during the next 7 days after intervention. Additional infarction was experienced by 61.1% of patients.

CONCLUSIONS

IAN in a selective patient group resulted in a positive response with reduction of angiographic vasospasm and increase in cerebral perfusion as detected by PCT after 24 hours. Therefore, IAN appears more effective than intra-arterial papaverine. Nevertheless the efficacy of IAN is temporary. Therefore, the search for more effective treatment strategies to reduce critical vasospasm and to improve cerebral perfusion must be continued.

Zusammenhang zwischen Rückenschmerzen und kernspintomografischen LWS-Befunden bei Hochleistungsvoltigierern

INTRODUCTION

A connection between morphologic lesions of the spine and specific sport disciplines incorporating torsional and hyperextension forces has been found. Although vaulting incorporates a significant amount of figures known from gymnastics, little is known about the influence of this sport on the lower back. The aim of our study was to assess to what extent vaulters suffer from back pain and whether these symptoms correlate to findings in magnetic resonance imaging (MRI) of the lumbar spine.

METHODS

20 high level vaulters ( [see text] age 21.95 [15 - 36] years) were included in the study. Using a standardised questionnaire biometric data, training intensity, localisation as well as intensity of back pain (VAS) was assessed. 12 of these vaulters agreed to an MRI scan of their lumbar spine. Scans were evaluated for morphologic changes using a semiquantative score and the results were correlated to clinical symptoms.

RESULTS

17 / 20 (85 %) reported of back pain of which 15 (75 %) had daily pain, the remaining 2 only occasionally. The average pain intensity on the visual analogue scale (VAS) was reported to be 3.76 +/- 0.53. The MRI scans revealed only slight degenerative changes of the lumbar spine. Statistical analysis of the data (Spearman's rank test) could not show a significant correlation between clinical symptoms and morphologic MRI-changes.

CONCLUSION

Vaulters, compared to riders of other disciplines, seem to suffer from recurrent back pain to a greater extent. Despite the fact that the lumbar spine is confronted with repetitive torsional and hyperextension forces, vaulters do not show undue early degenerative changes or marked lesions of the lumbar spine. Recurrent back pain in the vaulter is most likely due to functional problems. It seems unlikely that is based on manifest morphologic changes of the lower back.

Myocardial perfusion/metabolism mismatch and ventricular arrhythmias in the chronic post infarction state

AIM

Ventricular arrhythmias have been shown to originate in the myocardial peri-infarct region due to irregular heterotopic conduction. Hypoperfused but viable myocardium is often localised in those areas and may be involved in the pathogenesis of arrhythmias. We tested the hypothesis that these myocardial perfusion/metabolism mismatches (MM) are significantly associated with ventricular arrhythmias in the chronic post infarction state.

PATIENTS, METHODS

47 post infarction patients were included in the study. 33 suffered from ventricular arrhythmia whereas 14 did not. All patients underwent (99m)Tc tetrofosmin SPECT and (18)F-FDG PET. A region-of-interest(ROI)-analysis was used to assess viable myocardium based on predefined MM-criteria. Univariate analyses as well as a logistic regression model for the multivariate analysis were carried out.

RESULTS

94% of the arrhythmic patients displayed at least one MM-segment as compared to 64% of the non-arrhythmic patients. MM-segments and arrhythmia showed a statistically significant relation (p = 0.018). The logistic regression model predicted the occurrence or absence of arrhythmia in 85% of all cases. Multivariate analysis gave consistent results, after adjusting for symptomatic chronic heart failure (CHF), aneurysms and age.

CONCLUSION

Our results support the hypothesis that hypoperfused but viable myocardium represents an arrhythmogenic substrate and is a relevant risk factor for developing ventricular arrhythmias following myocardial infarction. Therefore, the detection of MM-segments allows the identification of patients with a higher risk for future cardiac events.

Occurrence of a sibling species complex within neotropical lymnaeids, snail intermediate hosts of fascioliasis

The delimitation of cryptic species within the genus Lymnaea, which are the main vectors of fascioliasis, remains a topic of controversy. An analysis of genetic variability based on 12 enzyme loci revealed different fixed alleles at 9 loci between two sympatric samples of Lymnaea viatrix at the type locality in Lima, Peru. The absence of heterozygotes within this locality indicates the presence of isolated populations or cryptic species within L. viatrix. Significant genetic differences were also found between these two L. viatrix samples from Lima and other populations of L. viatrix in South America and in addition to species such as L. truncatula, L. cubensis and L. columella. Moreover, the lack of variability within each Lymnaea samples studied indicates the existence of a high selfing rate in each species.

Evolutionary relationships and biogeography of Biomphalaria (Gastropoda: Planorbidae) with implications regarding its role as host of the human bloodfluke, Schistosoma mansoni

The wide geographic distribution of Schistosoma mansoni, a digenetic trematode and parasite of humans, is determined by the occurrence of its intermediate hosts, freshwater snails of the genus Biomphalaria (Preston 1910). We present phylogenetic analyses of 23 species of Biomphalaria, 16 Neotropical and seven African, including the most important schistosome hosts, using partial mitochondrial ribosomal 16S and complete nuclear ribosomal ITS1 and ITS2 nucleotide sequences. A dramatically better resolution was obtained by combining the data sets as opposed to analyzing each separately, indicating that there is additive congruent signal in each data set. Neotropical species are basal, and all African species are derived, suggesting an American origin for the genus. We confirm that a proto-Biomphalaria glabrata gave rise to all African species through a trans-Atlantic colonization of Africa. In addition, genetic distances among African species are smaller compared with those among Neotropical species, indicating a more recent origin. There are two species-rich clades, one African with B. glabrata as its base, and the other Neotropical. Within the African clade, a wide-ranging tropical savannah species, B. pfeifferi, and a Nilotic species complex, have both colonized Rift Valley lakes and produced endemic lacustrine forms. Within the Neotropical clade, two newly acquired natural hosts for S. mansoni (B. straminea and B. tenagophila) are not the closest relatives of each other, suggesting two separate acquisition events. Basal to these two species-rich clades are several Neotropical lineages with large genetic distances between them, indicating multiple lineages within the genus. Interesting patterns occur regarding schistosome susceptibility: (1) the most susceptible hosts belong to a single clade, comprising B. glabrata and the African species, (2) several susceptible Neotropical species are sister groups to apparently refractory species, and (3) some basal lineages are susceptible. These patterns suggest the existence of both inherent susceptibility and resistance, but also underscore the ability of S. mansoni to adapt to and acquire previously unsusceptible species as hosts. Biomphalaria schrammi appears to be distantly related to other Biomphalaria as well as to Helisoma, and may represent a separate or intermediate lineage.

The combined effect of isolation and Fasciola hepatica infection on the life history traits of Fossaria cubensis

Life history traits of Fossaria cubensis were compared between isolated and paired snails after infection with three miracidia of Fasciola hepatica. Four experimental groups were tested: isolated-unexposed, paired-unexposed, isolated-infected, and paired-infected. A repeated-measures ANOVA showed statistically significant interactions among isolation, infection, and age effects for shell size, number of egg masses per snail, number of eggs per snail, and number of viable eggs per snail. Isolated-unexposed snails exhibited the higher values of these variables and those of survival and finite and intrinsic rates of natural increase. Infection stimulated shell growth during the prepatent period, but differences were present only in paired snails since isolation causes a similar effect. Reproduction, in terms of the number of egg masses per snail and the number of eggs per mass per snail, decreases in the presence of parasitic infection, whereas isolation stimulates it. These effects were observed from early stages of infection.

The effect of isolation on the life-history traits of Pseudosuccinea columella (Pulmonata: Lymnaeidae)

A population of Pseudosuccinea columella was raised under laboratory conditions and its life tables were determined in isolated and paired snails. Isolated snails were significantly larger in shell size than paired snails from five weeks of age onward. Also, statistically significant differences were found for the number of eggs per mass per individual from week 5 to 9, isolated snails exhibiting the highest values. The intrinsic and finite rates of increase were greater in isolated than in paired snails. Either an inhibition of the reproductive output between individuals or the advantage of selfing may be the cause of the differences in this species, acting as a possible mechanism that increase the fitness of isolated snails.

Life-history traits of Fossaria cubensis (Gastropoda: Lymnaeidae) under experimental exposure to Fasciola hepatica (Trematoda: Digenea)

The effect of exposing the lymnaeid snail Fossaria cubensis to the trematode Fasciola hepatica on the snail population's life-history traits was studied under laboratory conditions. Exposed individuals showed a lower survival rate than control snails, although from week 7 onward a slower decrease of this parameter in relation to the control group was observed. There were higher values of fecundity rate for the controls compared to the exposed group except during weeks 9, 10, 11 and 12, which was the time that followed the period when almost all of the infected snails died. Both the intrinsic and finite rates of natural increase were significantly higher for the control group, but exposed snails still attained a lower mean generation time. Age-specific trade-offs were found, mainly for the weekly increase in size versus the number of eggs per mass, the weekly increase in size versus the number of viable eggs per mass, the number of masses versus the hatching probability and the number of eggs versus the hatching probability. All these negative associations were significant for juveniles of both control and exposed snails and not for adults; however, exposed young individuals exhibited much higher values of the correlation coefficient than control animals.

Genetic evidence of two species in the Biomphalaria havanensis complex (Gastropoda. Planorbidae) from Cuba

In Cuba, several species of freshwater gastropods belonging to the genus Biomphalaria have been described according to morphological characters. However, the taxonomy of this group remains unclear and a number of synonyms are often cited in the literature. This is the case for B. havanensis whose taxonomical status is not well established. Multilocus enzyme electrophoresis at 18 loci was carried out on adult snails of B. havanensis from the type locality in Havana and from several other sites harbouring a morphologically slightly different form, referred to here as Biomphalaria sp. Another local distinct species B. helophila was used as an outgroup. Allelic distribution showed the presence of nine and 12 diagnostic loci between B. havanensis and Biomphalaria sp. and B. helophila, respectively. We detected eight fixed alleles between Biomphalaria sp. and B. helophila. The genetic divergence estimated by absolute genetic distances strongly supports the assumption that Biomphalaria sp. is quite different from the sympatric B. havanensis, morphologically the closest species.