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1.
eNeuro ; 10(7)2023 07.
Article in English | MEDLINE | ID: mdl-37433683

ABSTRACT

About one-third of individuals living with epilepsy have treatment-resistant seizures. Alternative therapeutic strategies are thus urgently needed. One potential novel treatment target is miRNA-induced silencing, which is differentially regulated in epilepsy. Inhibitors (antagomirs) of specific microRNAs (miRNAs) have shown therapeutic promise in preclinical epilepsy studies; however, these studies were mainly conducted in male rodent models, and research into miRNA regulation in females and by female hormones in epilepsy is scarce. This is problematic because female sex and the menstrual cycle can affect the disease course of epilepsy and may, therefore, also alter the efficacy of potential miRNA-targeted treatments. Here, we used the proconvulsant miRNA miR-324-5p and its target, the potassium channel Kv4.2, as an example to test how miRNA-induced silencing and the efficacy of antagomirs in epilepsy are altered in female mice. We showed that Kv4.2 protein is reduced after seizures in female mice similar to male mice; however, in contrast to male mice, miRNA-induced silencing of Kv4.2 is unchanged, and miR-324-5p activity, as measured by the association with the RNA-induced silencing complex, is reduced in females after seizure. Moreover, an miR-324-5p antagomir does not consistently reduce seizure frequency or increase Kv4.2 in female mice. As a possible underlying mechanism, we found that miR-324-5p activity and the silencing of Kv4.2 in the brain were differentially correlated with plasma levels of 17ß-estradiol and progesterone. Our results suggest that hormonal fluctuations in sexually mature female mice influence miRNA-induced silencing and could alter the efficacy of potential future miRNA-based treatments for epilepsy in females.


Subject(s)
Epilepsy , MicroRNAs , Mice , Male , Female , Animals , MicroRNAs/genetics , Antagomirs/pharmacology , Progesterone/metabolism , Estradiol/metabolism , Hippocampus/metabolism , Disease Models, Animal , Seizures/chemically induced , Epilepsy/metabolism
2.
J Perinatol ; 36(7): 522-8, 2016 07.
Article in English | MEDLINE | ID: mdl-26938922

ABSTRACT

OBJECTIVE: Determine the relative influence of patient characteristics on Maternal-Fetal Medicine (MFM) physicians' willingness to intervene when managing 23-week preterm premature rupture of membranes. STUDY DESIGN: Surveyed 750 randomly sampled US members of the Society of Maternal-Fetal Medicine. Physicians rated their willingness to offer induction, order steroids and perform cesarean across eight vignettes; then completed a questionnaire querying expectations about neonatal outcomes and demographics. RESULTS: Three hundred and twenty-five (43%) MFMs responded. Patient characteristics only influenced ⩽11% of participants' willingness ratings. Overall, provider characteristics and institutional norms were associated with willingness to perform antenatal interventions, for example, practice region was associated with willingness to offer induction (P<0.001), order steroids (P=0.008) and perform cesarean for distress (P=0.011); while institutional cesarean cutoffs were associated with willingness to order steroids and perform cesarean for labor and distress (all P<0.001). CONCLUSION: Physician-level factors and institutional norms, more so than patient characteristics, may drive periviable care and outcomes.


Subject(s)
Attitude of Health Personnel , Fetal Membranes, Premature Rupture , Mothers , Physicians/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Adult , Aged , Female , Humans , Male , Malpractice/legislation & jurisprudence , Malpractice/statistics & numerical data , Middle Aged , Obstetrics , Regression Analysis , Religion , Societies, Medical , Surveys and Questionnaires , United States
3.
Malar J ; 15: 107, 2016 Feb 19.
Article in English | MEDLINE | ID: mdl-26895980

ABSTRACT

The fight against malaria is increasingly threatened by failures in vector control due to growing insecticide resistance. This review examines the recent primary research that addresses the putative relationship between agricultural insecticide use and trends in insecticide resistance. To do so, descriptive evidence offered by the new research was categorized, and additional factors that impact the relationship between agricultural insecticide use and observed insecticide resistance in malaria vectors were identified. In 23 of the 25 relevant recent publications from across Africa, higher resistance in mosquito populations was associated with agricultural insecticide use. This association appears to be affected by crop type, farm pest management strategy and urban development.


Subject(s)
Agriculture , Culicidae/drug effects , Insecticide Resistance/drug effects , Insecticides/pharmacology , Malaria/transmission , Agriculture/methods , Agriculture/statistics & numerical data , Animals , Humans , Malaria/prevention & control
4.
Trans R Soc Trop Med Hyg ; 110(2): 107-17, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26822603

ABSTRACT

BACKGROUND: Major gains have been made in reducing malaria transmission in many parts of the world, principally by scaling-up coverage with long-lasting insecticidal nets and indoor residual spraying. Historically, choice of vector control intervention has been largely guided by a parameter sensitivity analysis of George Macdonald's theory of vectorial capacity that suggested prioritizing methods that kill adult mosquitoes. While this advice has been highly successful for transmission suppression, there is a need to revisit these arguments as policymakers in certain areas consider which combinations of interventions are required to eliminate malaria. METHODS AND RESULTS: Using analytical solutions to updated equations for vectorial capacity we build on previous work to show that, while adult killing methods can be highly effective under many circumstances, other vector control methods are frequently required to fill effective coverage gaps. These can arise due to pre-existing or developing mosquito physiological and behavioral refractoriness but also due to additive changes in the relative importance of different vector species for transmission. Furthermore, the optimal combination of interventions will depend on the operational constraints and costs associated with reaching high coverage levels with each intervention. CONCLUSIONS: Reaching specific policy goals, such as elimination, in defined contexts requires increasingly non-generic advice from modelling. Our results emphasize the importance of measuring baseline epidemiology, intervention coverage, vector ecology and program operational constraints in predicting expected outcomes with different combinations of interventions.


Subject(s)
Anopheles/parasitology , Disease Eradication/methods , Insecticides , Malaria/prevention & control , Mosquito Control , Animals , Health Policy , Humans , Life Cycle Stages , Malaria/transmission , Mosquito Control/methods , Public Health Surveillance
5.
J Perinatol ; 35(8): 553-7, 2015 Aug.
Article in English | MEDLINE | ID: mdl-25927269

ABSTRACT

OBJECTIVE: To describe obstetricians' induction counseling practices for 22-week preterm premature rupture of membranes (PPROM) and identify provider characteristics associated with offering induction. METHODS: Surveyed 295 obstetricians on their likelihood (0-10) of offering induction for periviable PPROM across 10 vignettes. Twenty-two-week vignettes were analyzed, stratified by parental resuscitation preference. Bivariate analyses identified physician characteristics associated with reported likelihood ratings. RESULTS: Obstetricians (N=205) were not likely to offer induction. Median ratings by preference were as follows: resuscitation 1.0, uncertain 1.0 and comfort care 3.0. Only 41% of obstetricians were likely to offer induction to patients desiring comfort care. In addition, several provider-level factors, including practice region, parenting status and years in practice, were significantly associated with offering induction. CONCLUSIONS: Obstetricians do not readily offer induction when counseling patients with 22-week ruptured membranes, even when patients prefer palliation. This may place women at risk for infectious complications without accruing a neonatal benefit from prolonged latency.


Subject(s)
Fetal Membranes, Premature Rupture/therapy , Infant, Extremely Premature , Labor, Induced/classification , Physicians/statistics & numerical data , Premature Birth , Adult , Aged , Clinical Decision-Making , Female , Gestational Age , Humans , Infant, Newborn , Male , Middle Aged , Obstetrics , Pregnancy , Surveys and Questionnaires
6.
Int Health ; 7(2): 121-9, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25733562

ABSTRACT

BACKGROUND: Standard advice regarding vector control is to prefer interventions that reduce the lifespan of adult mosquitoes. The basis for this advice is a decades-old sensitivity analysis of 'vectorial capacity', a concept relevant for most malaria transmission models and based solely on adult mosquito population dynamics. Recent advances in micro-simulation models offer an opportunity to expand the theory of vectorial capacity to include both adult and juvenile mosquito stages in the model. METHODS: In this study we revisit arguments about transmission and its sensitivity to mosquito bionomic parameters using an elasticity analysis of developed formulations of vectorial capacity. RESULTS: We show that reducing adult survival has effects on both adult and juvenile population size, which are significant for transmission and not accounted for in traditional formulations of vectorial capacity. The elasticity of these effects is dependent on various mosquito population parameters, which we explore. Overall, control is most sensitive to methods that affect adult mosquito mortality rates, followed by blood feeding frequency, human blood feeding habit, and lastly, to adult mosquito population density. CONCLUSIONS: These results emphasise more strongly than ever the sensitivity of transmission to adult mosquito mortality, but also suggest the high potential of combinations of interventions including larval source management. This must be done with caution, however, as policy requires a more careful consideration of costs, operational difficulties and policy goals in relation to baseline transmission.


Subject(s)
Culicidae , Insect Vectors , Life Cycle Stages , Malaria/prevention & control , Mosquito Control , Population Dynamics , Adult , Animals , Anopheles , Ecology , Health Policy , Humans , Larva , Malaria/transmission , Models, Biological , Population Density
7.
Heart Rhythm ; 12(4): 699-705, 2015 Apr.
Article in English | MEDLINE | ID: mdl-25595923

ABSTRACT

BACKGROUND: Although often short-lived and self-limiting, postoperative atrial fibrillation (POAF) is a well-recognized postoperative complication of cardiac surgery and is associated with a 2-fold increase in cardiovascular mortality and morbidity. OBJECTIVE: Our aim was to determine whether intraoperative bilateral pulmonary vein radiofrequency ablation decreases the incidence of POAF in patients undergoing coronary artery bypass grafting (CABG). METHODS: A total of 175 patients undergoing CABG was prospectively randomized to undergo adjuvant bilateral radiofrequency pulmonary vein ablation in addition to CABG (group A; n = 89) or CABG alone (group B; n = 86). Intraoperative pulmonary vein isolation was confirmed by the inability to pace the heart via the pulmonary veins after ablation. All patients received postoperative ß-blocker. RESULTS: There was no difference in the incidence of POAF in the treatment group who underwent adjuvant pulmonary vein ablation (group A; 37.1%) compared with the control group who did not (group B; 36.1%) (P = .887). There were no differences in postoperative inotropic support, antiarrhythmic drug use, need for oral anticoagulation, and complication rates. The mean length of postoperative hospital stay was 8.2 ± 6.5 days in the ablation group and 6.7 ± 4.6 days in the control group (P < .001). CONCLUSION: Adjuvant pulmonary vein isolation does not decrease the incidence of POAF or its clinical impact but increases the mean length of stay in the hospital. The mechanism of POAF does not appear to depend on the pulmonary veins.


Subject(s)
Atrial Fibrillation , Catheter Ablation/methods , Coronary Artery Bypass/adverse effects , Postoperative Complications , Pulmonary Veins/surgery , Aged , Atrial Fibrillation/epidemiology , Atrial Fibrillation/etiology , Atrial Fibrillation/surgery , Canada , Coronary Artery Bypass/methods , Female , Humans , Incidence , Length of Stay , Male , Middle Aged , Outcome Assessment, Health Care , Postoperative Care/methods , Postoperative Care/statistics & numerical data , Postoperative Complications/epidemiology , Postoperative Complications/surgery
8.
J Perinatol ; 35(3): 161-6, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25254331

ABSTRACT

OBJECTIVE: To determine the relative influence of patients' resuscitation preferences on periviable delivery management. STUDY DESIGN: Surveyed 295 obstetrician-gynecologists about managing periviable preterm premature rupture of membranes. Across 10 vignettes, we systematically varied gestational age, occupation, method of conception and resuscitation preference. Physicians rated their likelihood (0 to 10) of proceeding with induction, steroids and cesarean. Data were analyzed via conjoint analysis. RESULT: Two hundred and five physician responses were included. Median ratings for management decisions were: induction 1.89; steroids 5.00; cesarean for labor 3.89; and cesarean for distress 4.11. Gestational age had the greatest influence on physician ratings across all decisions (importance values ranging from 72.6 to 86.6), followed by patient's resuscitation preference (range=9.3 to 21.4). CONCLUSION: Gestational age is weighted more heavily than patients' resuscitation preferences in obstetricians' decision making for periviable delivery management. Misalignment of antenatal management with parental resuscitation preferences may adversely affect periviable outcomes. Interventions are needed to facilitate more patient-centered decision making in periviable care.


Subject(s)
Decision Making , Fetal Viability , Resuscitation , Adult , Aged , Cesarean Section , Female , Gestational Age , Humans , Labor, Induced , Male , Middle Aged , Obstetrics , Patient Preference , Physicians
9.
J Perinatol ; 35(5): 338-43, 2015 May.
Article in English | MEDLINE | ID: mdl-25357097

ABSTRACT

OBJECTIVE: Test the association between provider characteristics and antenatal interventions offered for periviable delivery. STUDY DESIGN: Six hundred surveys mailed to members of the College's Collaborative Ambulatory Research Network. Items queried physicians' practices regarding administering steroids, recommending cesarean (for breech) and offering induction (for ruptured membranes) at 23 weeks. RESULT: Three hundred and ten (52%) obstetricians (OBs) responded. Respondents reported institutional cutoffs of 23 weeks for resuscitation (34%) and 24 weeks for cesarean (35%), whereas personal preferences for cesarean were ⩾25 weeks (44%). At 23 weeks, two-thirds ordered steroids, 43% recommended cesarean and 23% offered induction. In multivariable analyses, institutional cutoffs and providers' personal preferences predicted steroid administration (odds ratio, OR=4.37; 95% confidence interval, CI=1.73 to 11.00; OR=0.30, 95% CI=0.13 to 0.70); institutional cutoffs and the impression that cesarean decreases neurodevelopmental disability predicted recommending cesarean (OR=3.09, 95% CI=1.13 to 8.44; OR=6.41, 95% CI=2.06 to 19.91). For offering induction, practice location and religious service attendance approached, but did not meet, statistical significance (P=0.06 and P=0.05). CONCLUSION: OBs' willingness to intervene can impact periviable outcomes. These findings suggest that personal and institutional factors may influence obstetrical counseling and decision-making.


Subject(s)
Attitude of Health Personnel , Cesarean Section/statistics & numerical data , Labor, Induced/statistics & numerical data , Physicians/statistics & numerical data , Practice Patterns, Physicians' , Adult , Aged , Decision Making , Female , Fetal Viability , Humans , Male , Middle Aged , Multivariate Analysis , Obstetrics/methods , Surveys and Questionnaires
10.
J Perinatol ; 35(5): 344-8, 2015 May.
Article in English | MEDLINE | ID: mdl-25474555

ABSTRACT

OBJECTIVE: To compare the management options, risks and thematic content that obstetricians and neonatologists discuss in periviable counseling. STUDY DESIGN: Sixteen obstetricians and 15 neonatologists counseled simulated patients portraying a pregnant woman with ruptured membranes at 23 weeks of gestation. Transcripts from video-recorded encounters were qualitatively and quantitatively analyzed for informational content and decision-making themes. RESULT: Obstetricians more frequently discussed antibiotics (P=0.005), maternal risks (<0.001) and cesarean risks (<0.005). Neonatologists more frequently discussed neonatal complications (P=0.044), resuscitation (P=0.015) and palliative options (P=0.023). Obstetricians and neonatologists often deferred questions about steroid administration to the other specialty. Both specialties organized decision making around medical information, survival, quality of life, time and support. Neonatologists also introduced themes of values, comfort or suffering, and uncertainty. CONCLUSION: Obstetricians and neonatologists provided complementary counseling content to patients, yet neither specialty took ownership of steroid discussions. Joint counseling and/or family meetings may minimize observed redundancy and inconsistencies in counseling.


Subject(s)
Counseling , Neonatology , Obstetrics , Physicians/statistics & numerical data , Adult , Aged , Decision Making , Female , Fetal Viability , Gestational Age , Humans , Male , Middle Aged , Quality of Life , Video Recording
11.
J Natl Cancer Inst ; 107(1): 367, 2015 Jan.
Article in English | MEDLINE | ID: mdl-25505228

ABSTRACT

BACKGROUND: There is limited evidence on the association between dietary folate intake and the risk of breast cancer (BC) by hormone receptor expression in the tumors. We investigated the relationship between dietary folate and BC risk using data from the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: A total of 367993 women age 35 to 70 years were recruited in 10 European countries. During a median follow-up of 11.5 years, 11575 women with BC were identified. Dietary folate intake was estimated from country-specific dietary questionnaires. Cox proportional hazards regression models were used to quantify the association between dietary variables and BC risk. BC tumors were classified by receptor status. Subgroup analyses were performed by menopausal status and alcohol intake. Intake of other B vitamins was considered. All statistical tests were two-sided. RESULTS: A borderline inverse association was observed between dietary folate and BC risk (hazard ratio comparing top vs bottom quintile [HRQ5-Q1] = 0.92, 95% CI = 0.83 to 1.01, P trend = .037). In premenopausal women, we observed a statistically significant trend towards lower risk in estrogen receptor-negative BC (HRQ5-Q1 = 0.66, 95% CI = 0.45 to 0.96, P trend = .042) and progesterone receptor-negative BC (HRQ5-Q1 = 0.70, 95% CI = 0.51 to 0.97, P trend = .021). No associations were found in postmenopausal women. A 14% reduction in BC risk was observed when comparing the highest with the lowest dietary folate tertiles in women having a high (>12 alcoholic drinks/week) alcohol intake (HRT3-T1 = 0.86, 95% CI = 0.75 to 0.98, P interaction = .035). CONCLUSIONS: Higher dietary folate intake may be associated with a lower risk of sex hormone receptor-negative BC in premenopausal women.


Subject(s)
Breast Neoplasms/epidemiology , Breast Neoplasms/prevention & control , Folic Acid/administration & dosage , Vitamin B Complex/administration & dosage , Adult , Aged , Breast Neoplasms/chemistry , Europe/epidemiology , Female , Follow-Up Studies , Humans , Middle Aged , Odds Ratio , Premenopause , Prospective Studies , Receptors, Estrogen/analysis
12.
Clin Genet ; 88(6): 550-7, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25492405

ABSTRACT

Short-rib thoracic dystrophies (SRTDs) are congenital disorders due to defects in primary cilium function. SRTDs are recessively inherited with mutations identified in 14 genes to date (comprising 398 exons). Conventional mutation detection (usually by iterative Sanger sequencing) is inefficient and expensive, and often not undertaken. Whole exome massive parallel sequencing has been used to identify new genes for SRTD (WDR34, WDR60 and IFT172); however, the clinical utility of whole exome sequencing (WES) has not been established. WES was performed in 11 individuals with SRTDs. Compound heterozygous or homozygous mutations were identified in six confirmed SRTD genes in 10 individuals (IFT172, DYNC2H1, TTC21B, WDR60, WDR34 and NEK1), giving overall sensitivity of 90.9%. WES data from 993 unaffected individuals sequenced using similar technology showed two individuals with rare (minor allele frequency <0.005) compound heterozygous variants of unknown significance in SRTD genes (specificity >99%). Costs for consumables, laboratory processing and bioinformatic analysis were

Subject(s)
Abnormalities, Multiple/genetics , Exome/genetics , Genetic Predisposition to Disease/genetics , Mutation , Ribs/abnormalities , Sequence Analysis, DNA/methods , Thorax/pathology , Abnormalities, Multiple/diagnosis , Adaptor Proteins, Signal Transducing/genetics , Adult , Carrier Proteins/genetics , Cell Cycle Proteins/genetics , Child , Child, Preschool , Cytoplasmic Dyneins/genetics , Cytoskeletal Proteins , Genotype , Humans , Infant, Newborn , Microtubule-Associated Proteins/genetics , NIMA-Related Kinase 1 , Protein Serine-Threonine Kinases/genetics , Reproducibility of Results , Sensitivity and Specificity
13.
PLoS One ; 9(4): e94130, 2014.
Article in English | MEDLINE | ID: mdl-24714027

ABSTRACT

Forecasts of influenza activity in human populations could help guide key preparedness tasks. We conducted a scoping review to characterize these methodological approaches and identify research gaps. Adapting the PRISMA methodology for systematic reviews, we searched PubMed, CINAHL, Project Euclid, and Cochrane Database of Systematic Reviews for publications in English since January 1, 2000 using the terms "influenza AND (forecast* OR predict*)", excluding studies that did not validate forecasts against independent data or incorporate influenza-related surveillance data from the season or pandemic for which the forecasts were applied. We included 35 publications describing population-based (N = 27), medical facility-based (N = 4), and regional or global pandemic spread (N = 4) forecasts. They included areas of North America (N = 15), Europe (N = 14), and/or Asia-Pacific region (N = 4), or had global scope (N = 3). Forecasting models were statistical (N = 18) or epidemiological (N = 17). Five studies used data assimilation methods to update forecasts with new surveillance data. Models used virological (N = 14), syndromic (N = 13), meteorological (N = 6), internet search query (N = 4), and/or other surveillance data as inputs. Forecasting outcomes and validation metrics varied widely. Two studies compared distinct modeling approaches using common data, 2 assessed model calibration, and 1 systematically incorporated expert input. Of the 17 studies using epidemiological models, 8 included sensitivity analysis. This review suggests need for use of good practices in influenza forecasting (e.g., sensitivity analysis); direct comparisons of diverse approaches; assessment of model calibration; integration of subjective expert input; operational research in pilot, real-world applications; and improved mutual understanding among modelers and public health officials.


Subject(s)
Global Health , Influenza, Human/epidemiology , Models, Statistical , Disease Outbreaks , Forecasting , Humans
14.
Malar J ; 12: 206, 2013 Jun 15.
Article in English | MEDLINE | ID: mdl-23767770

ABSTRACT

BACKGROUND: Plasmodium infections trigger complex immune reactions from their hosts against several life stages of the parasite, including gametocytes. These immune responses are highly variable, depending on age, genetics, and exposure history of the host as well as species and strain of parasite. Although the effects of host antibodies that act against gamete stages in the mosquito (due to uptake in the blood meal) are well documented, the effects of host immunity upon within-host gametocytes are not as well understood. This report consists of a theoretical population biology-based analysis to determine constraints that host immunity impose upon gametocyte population growth. The details of the mathematical models used for the analysis were guided by published reports of clinical and animal studies, incorporated plausible modalities of immune reactions to parasites, and were tailored to the life cycl es of the two most widespread human malaria pathogens, Plasmodium falciparum and Plasmodium vivax. RESULTS: For the same ability to bind and clear a target, the model simulations suggest that an antibody attacking immature gametocytes would tend to lower the overall density of transmissible mature gametocytes more than an antibody attacking the mature forms directly. Transmission of P. falciparum would be especially vulnerable to complete blocking by antibodies to its immature forms since its gametocytes take much longer to reach maturity than those of P. vivax. On the other hand, antibodies attacking the mature gametocytes directly would reduce the time the mature forms can linger in the host. Simulation results also suggest that varying the standard deviation in the time necessary for individual asexual parasites to develop and produce schizonts can affect the efficiency of production of transmissible gametocytes. CONCLUSIONS: If mature gametocyte density determines the probability of transmission, both Plasmodium species, but especially P. falciparum, could bolster this probability through evasion or suppression of host immune responses against the immature gametocytes. However, if the long term lingering of mature gametocytes at low density in the host is also important to ensure transmission, then evasion or suppression of antibodies against the mature stages would bolster probability of transmission as well.


Subject(s)
Malaria, Falciparum/immunology , Malaria, Falciparum/transmission , Malaria, Vivax/immunology , Malaria, Vivax/transmission , Plasmodium falciparum/immunology , Plasmodium vivax/immunology , Adult , Animals , Disease Models, Animal , Host-Parasite Interactions , Humans , Models, Theoretical
15.
Can J Surg ; 56(1): 21-6, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23187039

ABSTRACT

BACKGROUND: Cardiac retransplantation remains the most viable option for patients with allograft heart failure; however, careful patient selection is paramount considering limited allograft resources. We analyzed clinical outcomes following retransplantation in an academic, tertiary care institution. METHODS: Between 1981 and 2011, 593 heart transplantations, including 22 retransplantations were performed at our institution. We analyzed the preoperative demographic characteristics, cause of allograft loss, short- and long-term surgical outcomes and cause of death among patients who had cardiac retransplantations. RESULTS: Twenty-two patients underwent retransplantation: 10 for graft vascular disease, 7 for acute rejection and 5 for primary graft failure. Mean age at retransplantation was 43 (standard deviation [SD] 15) years; 6 patients were women. Thirteen patients were critically ill preoperatively, requiring inotropes and/or mechanical support. The median interval between primary and retransplantation was 2.2 (range 0-16) years. Thirty-day mortality was 31.8%, and conditional (> 30 d) 1-, 5- and 10-year survival after retransplantation were 93%, 79% and 59%, respectively. A diagnosis of allograft vasculopathy (p = 0.008) and an interval between primary and retransplantation greater than 1 year (p = 0.016) had a significantly favourable impact on 30-day mortality. The median and mean survival after retransplantation were 3.3 and 5 (SD 6, range 0-18) years, respectively; graft vascular disease and multiorgan failure were the most common causes of death. CONCLUSION: Long-term outcomes for primary and retransplantation are similar if patients survive the 30-day postoperative period. Retransplantation within 1 year of the primary transplantation resulted in a high perioperative mortality and thus may be a contraindication to retransplantation.


Subject(s)
Graft Rejection/surgery , Heart Failure/mortality , Heart Failure/surgery , Heart Transplantation , Adult , Female , Graft Rejection/etiology , Heart Transplantation/mortality , Heart Transplantation/standards , Humans , Immunosuppressive Agents/administration & dosage , Kaplan-Meier Estimate , Male , Medical Records , Middle Aged , Ontario , Patient Selection , Perioperative Period , Reoperation/mortality , Reoperation/standards , Retrospective Studies , Risk Factors , Tertiary Healthcare , Time Factors , Transplantation, Homologous , Treatment Outcome
16.
Malar J ; 11: 396, 2012 Nov 28.
Article in English | MEDLINE | ID: mdl-23190739

ABSTRACT

BACKGROUND: Although 80% of malaria occurs in children under five years of age, infants under six months of age are known to have low rates of infection and disease. It is not clear why this youngest age group is protected; possible factors include maternal antibodies, unique nutrition (breast milk), and the presence of foetal haemoglobin (HbF). This work aims to gain insight into possible mechanisms of protection, and suggest pathways for focused empirical work, by modelling a range of possible effects of foetal haemoglobin and other red blood cell (RBC) developmental changes on parasite dynamics in infants. METHODS: A set of ordinary differential equations was created to investigate the leading hypotheses about the possible protective mechanisms of HbF-containing red blood cells, in particular whether HbF suppresses parasite population growth because parasite multiplication in individual RBCs is lower, slower or absent. The model also incorporated the intrinsic changes in blood volume and haematocrit that occur with age, and the possibility of parasite affinities for HbF-containing RBCs or reticulocytes. RESULTS: The model identified several sets of conditions in which the infant remained protected, or displayed a much slower growth of parasitaemia in the first few months of life, without any intervening immune response. The most protective of the hypothesized mechanisms would be the inhibition of schizont division in foetal RBCs so that fewer merozoites are produced. The model showed that a parasite preference for HbF-containing RBCs increases protective effects for the host, while a preference for reticulocytes has little effect. CONCLUSIONS: The results from this simple model of haematological changes in infants and their effects on Plasmodium falciparum infection dynamics emphasize the likely importance of HbF and RBC number as an explanatory factor in paediatric malaria, and suggest a framework for organizing related empirical research.


Subject(s)
Fetal Hemoglobin/metabolism , Malaria, Falciparum/blood , Malaria, Falciparum/parasitology , Age Factors , Blood Volume , Child, Preschool , Erythrocytes/metabolism , Erythrocytes/parasitology , Host-Parasite Interactions , Humans , Infant , Infant, Newborn , Models, Biological , Parasitemia/blood , Parasitemia/parasitology , Plasmodium falciparum/growth & development , Plasmodium falciparum/pathogenicity , Reticulocytes/metabolism , Reticulocytes/parasitology
17.
PLoS Pathog ; 8(4): e1002588, 2012.
Article in English | MEDLINE | ID: mdl-22496640

ABSTRACT

Ronald Ross and George Macdonald are credited with developing a mathematical model of mosquito-borne pathogen transmission. A systematic historical review suggests that several mathematicians and scientists contributed to development of the Ross-Macdonald model over a period of 70 years. Ross developed two different mathematical models, Macdonald a third, and various "Ross-Macdonald" mathematical models exist. Ross-Macdonald models are best defined by a consensus set of assumptions. The mathematical model is just one part of a theory for the dynamics and control of mosquito-transmitted pathogens that also includes epidemiological and entomological concepts and metrics for measuring transmission. All the basic elements of the theory had fallen into place by the end of the Global Malaria Eradication Programme (GMEP, 1955-1969) with the concept of vectorial capacity, methods for measuring key components of transmission by mosquitoes, and a quantitative theory of vector control. The Ross-Macdonald theory has since played a central role in development of research on mosquito-borne pathogen transmission and the development of strategies for mosquito-borne disease prevention.


Subject(s)
Communicable Disease Control , Culicidae , Disease Transmission, Infectious/prevention & control , Malaria/prevention & control , Malaria/transmission , Models, Biological , Animals , Disease Transmission, Infectious/history , History, 20th Century , Humans , Malaria/history
18.
Malar J ; 11: 64, 2012 Mar 06.
Article in English | MEDLINE | ID: mdl-22394452

ABSTRACT

WHO estimates that 80% of mortality due to malaria occurs among infants and young children. Though it has long been established that malaria disproportionately affects children under age five, our understanding of the underlying biological mechanisms for this distribution remains incomplete. Many studies use age as an indicator of exposure, but age may affect malaria burden independently of previous exposure. Not only does the severity of malaria infection change with age, but the clinical manifestation of disease does as well: younger children are more likely to suffer severe anaemia, while older children are more likely to develop cerebral malaria. Intensity of transmission and acquired immunity are important determinants of this age variation, but age differences remain consistent over varying transmission levels. Thus, age differences in clinical presentation may involve inherent age-related factors as well as still-undiscovered facets of acquired immunity, perhaps including the rates at which relevant aspects of immunity are acquired. The concept of "allometry" - the relative growth of a part in relation to that of an entire organism or to a standard - has not previously been applied in the context of malaria infection. However, because malaria affects a number of organs and cells, including the liver, red blood cells, white blood cells, and spleen, which may intrinsically develop at rates partly independent of each other and of a child's overall size, developmental allometry may influence the course and consequences of malaria infection. Here, scattered items of evidence have been collected from a variety of disciplines, aiming to suggest possible research paths for investigating exposure-independent age differences affecting clinical outcomes of malaria infection.


Subject(s)
Anemia/pathology , Biometry , Malaria, Cerebral/pathology , Malaria, Falciparum/pathology , Adaptive Immunity , Age Factors , Anemia/complications , Anemia/immunology , Anemia/parasitology , Antibodies, Protozoan/blood , Antibodies, Protozoan/immunology , Child , Child, Preschool , Erythrocytes/parasitology , Erythrocytes/pathology , Humans , Immunoglobulins/blood , Immunoglobulins/immunology , Infant , Leukocytes/parasitology , Leukocytes/pathology , Liver/parasitology , Liver/pathology , Malaria, Cerebral/complications , Malaria, Cerebral/immunology , Malaria, Cerebral/parasitology , Malaria, Falciparum/complications , Malaria, Falciparum/immunology , Malaria, Falciparum/parasitology , Plasmodium falciparum , Prognosis , Severity of Illness Index , Spleen/parasitology , Spleen/pathology
19.
PLoS One ; 6(12): e28347, 2011.
Article in English | MEDLINE | ID: mdl-22162764

ABSTRACT

Anopheles mosquitoes are important vectors of malaria and lymphatic filariasis (LF), which are major public health diseases in Nigeria. Malaria is caused by infection with a protozoan parasite of the genus Plasmodium and LF by the parasitic worm Wuchereria bancrofti. Updating our knowledge of the Anopheles species is vital in planning and implementing evidence based vector control programs. To present a comprehensive report on the spatial distribution and composition of these vectors, all published data available were collated into a database. Details recorded for each source were the locality, latitude/longitude, time/period of study, species, abundance, sampling/collection methods, morphological and molecular species identification methods, insecticide resistance status, including evidence of the kdr allele, and P. falciparum sporozoite rate and W. bancrofti microfilaria prevalence. This collation resulted in a total of 110 publications, encompassing 484,747 Anopheles mosquitoes in 632 spatially unique descriptions at 142 georeferenced locations being identified across Nigeria from 1900 to 2010. Overall, the highest number of vector species reported included An. gambiae complex (65.2%), An. funestus complex (17.3%), An. gambiae s.s. (6.5%). An. arabiensis (5.0%) and An. funestus s.s. (2.5%), with the molecular forms An. gambiae M and S identified at 120 locations. A variety of sampling/collection and species identification methods were used with an increase in molecular techniques in recent decades. Insecticide resistance to pyrethroids and organochlorines was found in the main Anopheles species across 45 locations. Presence of P. falciparum and W. bancrofti varied between species with the highest sporozoite rates found in An. gambiae s.s, An. funestus s.s. and An. moucheti, and the highest microfilaria prevalence in An. gambiae s.l., An. arabiensis, and An. gambiae s.s. This comprehensive geo-referenced database provides an essential baseline on Anopheles vectors and will be an important resource for malaria and LF vector control programmes in Nigeria.


Subject(s)
Anopheles/genetics , Anopheles/parasitology , Alleles , Animals , Data Collection , Databases, Factual , Drug Resistance , Geography , Insecticide Resistance/genetics , Insecticides/pharmacology , Nigeria , Plasmodium falciparum/metabolism , Public Health , Species Specificity , Sporozoites/metabolism , Time Factors , Wuchereria bancrofti/metabolism
20.
Neurology ; 76(17): 1514-9, 2011 Apr 26.
Article in English | MEDLINE | ID: mdl-21519002

ABSTRACT

OBJECTIVE: Two unrelated families were ascertained in which sisters had infantile onset of epilepsy and developmental delay. Mutations in the protocadherin 19 (PCDH19) gene cause epilepsy and mental retardation limited to females (EFMR). Despite both sister pairs having a PCDH19 mutation, neither parent in each family was a heterozygous carrier of the mutation. The possibility of parental mosaicism of PCDH19 mutations was investigated. METHODS: Genomic DNA from peripheral blood was obtained and sequenced for PCDH19 mutations. Parentage was confirmed by markers. RESULTS: Both sister pairs have a mutation in PCDH19. Sister pair 1 has a missense mutation, c.74T>C, L25P, while sequence analysis indicates both of their parents are negative for the mutation. Diagnostic restriction enzyme analysis detected low-level mosaicism of the mutation in their mother. Sister pair 2 are half-sisters who share a mother and each has the missense PCDH19 mutation c.1019 A>G, N340S. The sequence chromatograph of their mother shows reduced signal for the same mutation. These data indicate maternal somatic and gonadal mosaicism of the PCDH19 mutation in both sister pairs. Phenotyping is suggestive of, and PCDH19 mutation detection is diagnostic for, the disorder EFMR in the affected girls. CONCLUSIONS: We show that gonadal mosaicism of a PCDH19 mutation in a parent is an important molecular mechanism associated with the inheritance of EFMR. This should be considered when providing genetic counseling for couples who have one affected daughter as they may risk recurrence of affected daughters and having sons at risk of transmitting EFMR.


Subject(s)
Cadherins/genetics , Epilepsy/genetics , Family Health , Intellectual Disability/genetics , Parents , Polymorphism, Single Nucleotide/genetics , Adolescent , DNA Mutational Analysis , Epilepsy/complications , Female , Humans , Intellectual Disability/complications , Male , Mosaicism , Protocadherins , Recurrence , Young Adult
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