Is the peacock's train an honest signal of genetic quality at the major histocompatibility complex?

Peacocks are a classic example of sexual selection, where females preferentially mate with males who have longer, more elaborate trains. One of the central hypotheses of sexual selection theory is that large or elaborate male 'ornaments' may signal high genetic quality (good genes). Good genes are thought to be those associated with disease resistance and as diversity at the major histocompatibility complex (MHC) has been shown to equate to superior immune responses, we test whether the peacock's train reveals genetic diversity at the MHC. We demonstrate via a captive breeding experiment that train length of adult males reflects genetic diversity at the MHC while controlling for genome-wide diversity and that peahens lay more, and larger, eggs for males with a more diverse MHC, but not for males with longer trains. Our results suggest that females are assessing and responding to male quality in terms of MHC diversity, but this assessment does not appear to be via train length, despite the fact that train length reflects MHC diversity.

[Summary of the practice guideline 'allergic and non-allergic rhinitis' (first revision) from the Dutch College of General Practitioners]. / Samenvatting van de standaard 'Allergische en niet-allergische rhinitis' (eerste herziening) van het Nederlands Huisartsen Genootschap.

The practice guideline 'Allergic and non-allergic rhinitis' of the Dutch College ofGeneral Practitioners has been revised based on developments that have occurred in recent years. The most important modifications are: Impermeable covers for beddings are advised only for patients with serious complaints despite the use of medication and other mite-avoidance measures, and patients with allergic rhinitis with asthma. The indication for the use ofa corticosteroid nasal spray is broadened. There is more evidence for the efficacy ofa nasal spray with antihistamines. The indication for cromoglycate has been restricted. Two major unsolved points of discussion concerned the effectiveness of sublingual immunotherapy and the link between asthma and allergic rhinitis.

[Lengthening of the QT-interval in a newborn treated with cisapride]. / Verlenging van de QTc-tijd bij een pasgeborene tijdens gebruik van cisapride.

In a 7-week-old female infant a prolonged QTc interval, up to 485 ms, was measured and attributed to the use of the prokinetic agent cisapride. The girl was born at 32 1/7 weeks of gestational age, started to use cisapride (0.8 mg/kg/day) at the age of 7 weeks because of gastro-oesophageal reflux. After cessation of cisapride therapy, the QTc interval returned to normal. A normal QTc interval had also been observed before the use of cisapride. Because of the risk of QTc prolongation and possibly cardiac arrhythmias during the use of cisapride by newborn infants, electrocardiography should be performed before and during cisapride therapy; they should also be checked for possible risk factors like electrolyte disturbances and congenital QTc prolongation. Prudence is called for in case of patients with pre-existing disorders which could result in QT prolongation like electrolyte disturbances, congenital QT prolongation, and the concomitant use of medication associated with QT prolongation.

[Reversible tooth discoloration during oral use of antibiotics]. / Reversibele tandverkleuring tijdens oraal gebruik van antibiotica.

From January 1991 until June 1995. 25 cases were reported to the Netherlands Pharmacovigilance Foundation LAREB of yellow to brown tooth discoloration following the oral use of medication; 21 cases (84%) involved antibiotics, of which 14 were amoxicillin. 17/21 patients were children, with ages ranging from 1 to 10 years. All children used liquid formulations (suspension or solutabs). Discoloration was reversible in all cases, but had a protracted course in some. Presumably a pigment precipitated on (and not in) the teeth, but the nature of the pigment was uncertain.

Risk of venous thrombosis in patients with chronic kidney disease: identification of high-risk groups.

BACKGROUND: Although an association between venous thrombosis and chronic kidney disease has recently been established, it is unknown which patients with chronic kidney disease are most likely to benefit from thromboprophylaxis. OBJECTIVE: The aim of this study was to assess the association between venous thrombosis and chronic kidney disease in combination with arterial thrombosis, malignancy, surgery and thrombophilia to identify high-risk groups as a basis for personalized prevention. METHODS: This study included 2473 consecutive patients with first venous thrombosis and 2936 controls from a case-control study (the MEGA study). RESULTS: Moderately decreased kidney function (eGFR 30-60 mL min(-1) ) was associated with a 2.5-fold (95% CI, 1.9-3.4) increased risk and severely decreased kidney function (eGFR < 30 mL min(-1) ) was associated with a 5.5-fold (95% CI 1.8-16.7) increased risk of venous thrombosis, compared with those with normal kidney function (eGFR > 90 mL min(-1) ). The risk of venous thrombosis was additionally increased for moderately and severely reduced kidney function in combination with arterial thrombosis (odds ratio, 4.9; 95% CI, 2.2-10.9), malignancy (5.8; 95% CI, 2.8-12.1), surgery (14.0; 95%, CI 5.0-39.4), immobilization (17.1; 95% CI, 6.8-43.0) or thrombophilia (odds ratios, 4.3-9.5), with particularly high risks when three or more risk factors were present (odds ratio, 56.3; 95% CI, 7.6-419.3). CONCLUSION: Decreased kidney function is associated with an increased risk of venous thrombosis. The risk increased substantially in the presence of one or more other risk factors for thrombosis.

Risk of venous thrombosis in patients with major illnesses: results from the MEGA study.

BACKGROUND: The risk of venous thrombosis associated with major illnesses is not well known, and neither is the risk associated with the combined effect of immobilization and thrombophilia. The aim of this study was to assess the effect on the development of venous thrombosis of several major illnesses in combination with immobilization, body mass index, and thrombophilia, to identify high-risk groups that may provide a basis for personalized prevention. METHODS: This study included 4311 consecutive patients with a first episode of venous thrombosis, and 5768 controls from a case-control study (MEGA study). We calculated odds ratios (ORs) for venous thrombosis for patients with a self-reported history of major illnesses. RESULTS: Venous thrombosis risk was increased for all investigated major illnesses: liver disease, OR 1.7 (95% confidence interval [CI]1.0-2.9); kidney disease, OR 3.7 (95% CI 2.3-5.9); rheumatoid arthritis, OR 1.5 (95% CI 1.2-1.9); multiple sclerosis, OR 2.4 (95% CI 1.3-4.3); heart failure, OR 1.7 (95% CI 1.2-2.3); hemorrhagic stroke, OR 4.9 (95% CI 2.4-9.9); arterial thrombosis, OR 1.5 (95% CI 1.2-1.8); and the presence of any of the above major illnesses, OR 1.7 (95% CI 1.5-1.9). Combinations of major illnesses with immobilization and increased factor VIII (OR 79.9; 95% CI 33.2-192.2), increased FIX (OR 35.3; 95% CI 14.2-87.8), increased von Willebrand factor (OR 88.0; 95% CI 33.9-228.3), FV Leiden (OR 84.2; 95% CI 19.5-363.6), and blood group non-O (OR 53.1; 95% CI 30.9-91.4) were associated with increased venous thrombosis risks. CONCLUSIONS: All of the major illnesses reported here were associated with an increased risk of venous thrombosis. These risks were most pronounced at the time of immobilization or in the presence of thrombophilia.

Mortality due to pulmonary embolism, myocardial infarction, and stroke among incident dialysis patients.

BACKGROUND: It is has been suggested that dialysis patients have lower mortality rates for pulmonary embolism than the general population, because of platelet dysfunction and bleeding tendency. However, there is limited information whether dialysis is indeed associated with a decreased mortality risk from pulmonary embolism. OBJECTIVE: The aim of our study was to evaluate whether mortality rate ratios for pulmonary embolism were lower than for myocardial infarction and stroke in dialysis patients compared with the general population. METHODS: Cardiovascular causes of death for 130,439 incident dialysis patients registered in the ERA-EDTA Registry were compared with the cardiovascular causes of death for the European general population. RESULTS: The age- and sex-standardized mortality rate (SMR) from pulmonary embolism was 12.2 (95% CI 10.2-14.6) times higher in dialysis patients than in the general population. The SMRs in dialysis patients compared with the general population were 11.0 (95% CI 10.6-11.4) for myocardial infarction, 8.4 (95% CI 8.0-8.8) for stroke, and 8.3 (95% CI 8.0-8.5) for other cardiovascular diseases. In dialysis patients, primary kidney disease due to diabetes was associated with an increased mortality risk due to pulmonary embolism (HR 1.9; 95% CI 1.0-3.8), myocardial infarction (HR 4.1; 95% CI 3.4-4.9), stroke (HR 3.5; 95% CI 2.8-4.4), and other cardiovascular causes of death (HR 3.4; 95% CI 2.9-3.9) compared with patients with polycystic kidney disease. CONCLUSIONS: Dialysis patients were found to have an unexpected highly increased mortality rate for pulmonary embolism and increased mortality rates for myocardial infarction and stroke.

Chronic kidney disease stages 1-3 increase the risk of venous thrombosis.

BACKGROUND: End-stage renal disease has been associated with venous thrombosis (VT). However, the risk of VT in the early stages of chronic kidney disease (CKD) has not yet been investigated. The aim of this study was to investigate whether CKD patients with stage 1-3 disease are at increased risk of VT. METHODS: Eight thousand four hundred and ninety-five subjects were included in a prospective cohort study, in which renal function and albuminuria were assessed, starting in 1997-1998, and were followed for the occurrence of VT until 1 June 2007. CKD patients were staged according to the Kidney Disease Outcomes Quality Initiative guidelines, on the basis of 24-h urine albumin excretion and estimated glomerular filtration rates. Objectively verified symptomatic VT was considered to be the endpoint. RESULTS: Of the 8495 subjects, 243 had CKD stage 1, 856 CKD stage 2, and 491 CKD stage 3. During a median follow-up period of 9.2 years, 128 individuals developed VT. The hazard ratios (HRs) for CKD stages 1, 2 and 3 were, respectively, 2.2 [95% confidence interval (CI) 0.9-5.1], 1.9 (95% CI 1.1-3.1) and 1.6 (95% CI 0.9-2.8) relative to those without CKD after adjustment for age, sex, body mass index, hypertension, diabetes, malignancy, and high-sensitivity C-reactive protein. Subjects with CKD stage 3 and albuminuria (≥ 30 mg d(-1)) had an adjusted HR of 3.0, and subjects with CKD stage 3 without albuminuria had an adjusted HR of 1.0. CONCLUSIONS: CKD stages 1 and 2, and CKD stage 3 in the presence of albuminuria, are risk factors for VT. The risk of VT is more related to albuminuria than to impaired glomerular filtration rate.

PERMANENT GENETIC RESOURCES: Polymorphic microsatellite loci and interspecific cross-amplification in the parasitoid wasps Megastigmus stigmatizans and Megastigmus dorsalis.

We isolated and characterized 19 polymorphic microsatellite loci in the congeneric parasitoid wasps Megastigmus stigmatizans and Megastigmus dorsalis associated with cynipid oak galls. Loci isolated from species-specific libraries showed extensive cross-amplification, resulting in a total of 15 polymorphic loci for M. stigmatizans and 13 for M. dorsalis.

Elevated plasma levels of clozapine after concomitant use of fluvoxamine.

Selective serotonin reuptake inhibitors can be added to clozapine therapy in order to treat remaining negative symptoms and obsessive compulsive symptoms. The present case report describes a 44-year-old man exhibiting extremely elevated plasma levels of clozapine after the addition of fluvoxamine, up to 4160 mcg/l. The elevated plasma levels of clozapine, which were discovered 6 months after the SSRI was added, is likely to be caused by a drug-drug interaction. Clozapine is a substrate of CYP 1A2 and is predominantly metabolised in the liver. Of the SSRIs, fluvoxamine is one of the most potent inhibitors of the isoenzyme CYP 1A2. This case serves to emphasise the need for continuous attention to drug-drug interactions, especially when they might be easily overlooked due to the lack of clear symptoms.

The role of tetraploids in the sexual-asexual cycle in dandelions (Taraxacum).

Apomictic plants often produce pollen that can function in crosses with related sexuals. Moreover, facultative apomicts can produce some sexual offspring. In dandelions, Taraxacum, a sexual-asexual cycle between diploid sexuals and triploid apomicts, has been described, based on experimental crosses and population genetic studies. Little is known about the actual hybridization processes in nature. We therefore studied the sexual-asexual cycle in a mixed dandelion population in the Netherlands. In this population, the frequencies of sexual diploids and triploids were 0.31 and 0.68, respectively. In addition, less than 1% tetraploids were detected. Diploids were strict sexuals, triploids were obligate apomicts, but tetraploids were most often only partly apomictic, lacking certain elements of apomixis. Tetraploid seed fertility in the field was significantly lower than that of apomictic triploids. Field-pollinated sexual diploids produced on average less than 2% polyploid offspring, implying that the effect of hybridization in the 2x-3x cycle in Taraxacum will be low. Until now, 2x-3x crosses were assumed to be the main pathway of new formation of triploid apomicts in the sexual-asexual cycle in Taraxacum. However, tetraploid pollen donors produced 28 times more triploid offspring in experimental crosses with diploid sexuals than triploid pollen donors. Rare tetraploids may therefore act as an important bridge in the formation of new triploid apomicts.