Mitochondrial gene in the nuclear genome induces reproductive barrier in rice

Hybrid incompatibility in F₁ hybrids or later generations is often observed as sterility or inviability. This incompatibility acts as postzygotic reproductive isolation, which results in the irreversible divergence of species. Here, we show that the reciprocal loss of duplicated genes encoding mitochondrial ribosomal protein L27 causes hybrid pollen sterility in F₁ hybrids of the cultivated rice Oryza sativa and its wild relative O. glumaepatula. Functional analysis revealed that this gene is essential for the later stage of pollen development, and distribution analysis suggests that the gene duplication occurred before the divergence of the AA genome species. On the basis of these results, we discuss the possible contribution of the “founder effect” in establishing this reproductive barrier.     

Incidental use of ecstasy: no evidence for harmful effects on cognitive brain function in a prospective fMRI study

RATIONALE: Heavy ecstasy use in humans has been associated with cognitive impairments and changes in cognitive brain function supposedly due to damage to the serotonin system. There is concern that even a single dose of 3,4-methylenedioxymethamphetamine may be neurotoxic, but very little is known about the consequences of a low dose of ecstasy for cognitive brain function. OBJECTIVES: The objective of the study was to assess the effects of a low dose of ecstasy on human cognitive brain function using functional magnetic resonance imaging (fMRI). MATERIALS AND METHOD: We prospectively studied, as part of the NeXT (Netherlands XTC toxicity) study, sustained effects of a low dose of ecstasy on brain function in 25 subjects before and after their first episode of ecstasy use (mean 2.0 +/- 1.4 ecstasy pills, on average 11.1 +/- 12.9 weeks since last ecstasy use), compared to 24 persistent ecstasy-naive controls, also measured twice and matched with the novice users on age, gender, IQ, and cannabis use. Cognitive brain function was measured in the domains of working memory, selective attention, and associative memory using fMRI. RESULTS: No significant effects were found of a low dose of ecstasy on working memory, selective attention, or associative memory neither at the behavioral level nor at the neurophysiological level. CONCLUSIONS: This study yielded no firm evidence for sustained effects of a low dose of ecstasy on human cognitive brain function. The present findings are relevant for the development of prevention and harm reduction strategies. Furthermore, the study is relevant to the discussion concerning potential therapeutic use of ecstasy.     

Assessment of cognitive brain function in ecstasy users and contributions of other drugs of abuse: results from an FMRI study.

Heavy ecstasy use has been associated with neurocognitive deficits in various behavioral and brain imaging studies. However, this association is not conclusive owing to the unavoidable confounding factor of polysubstance use. The present study, as part of the Netherlands XTC Toxicity study, investigated specific effects of ecstasy on working memory, attention, and associative memory, using functional magnetic resonance imaging (fMRI). A large sample (n=71) was carefully composed based on variation in the amount and type of drugs that were used. The sample included 33 heavy ecstasy users (mean 322 pills lifetime). Neurocognitive brain function in three domains: working memory, attention, and associative memory, was assessed with performance measures and fMRI. Independent effects of the use of ecstasy, amphetamine, cocaine, cannabis, alcohol, tobacco, and of gender and IQ were assessed and separated by means of multiple regression analyses. Use of ecstasy had no effect on working memory and attention, but drug use was associated with reduced associative memory performance. Multiple regression analysis showed that associative memory performance was affected by amphetamine much more than by ecstasy. Both drugs affected associative memory-related brain activity, but the effects were consistently in opposite directions, suggesting that different mechanisms are at play. This could be related to the different neurotransmitter systems these drugs predominantly act upon, that is, serotonin (ecstasy) vs dopamine (amphetamine) systems.     

Molecular identification of Ascaris lumbricoides and Ascaris suum recovered from humans and pigs in Thailand,Lao PDR,and Myanmar

Parasitology Research - Ascaris lumbricoides is the largest roundworm known from the human intestine while Ascaris suum is an internal parasite of pigs. Ascariasis, caused by Ascaris lumbricoides,...     

Anti-U and haemolytic disease of the fetus and newborn

The red cell alloantibody, anti-U, is uncommon but is a recognised cause of haemolytic disease of the fetus and newborn. We describe six pregnancies complicated by the presence of maternal anti-U, and review nine other well-documented cases. In these 15 cases severe haemolytic disease occurred only with titres of ≥ 1/512, and titres as high as 1/4000 were not necessarily associated with significant haemolysis. We recommend that an anti-U titre of ≥ 1/128 or more at ≥ 17 weeks of gestation is an indication for assessment of haemolysis in the fetus. Amniocentesis is the preferred initial investigation.     

Comparison of combinations of parenteral artemisinin derivatives plus oral mefloquine with intravenous quinine plus oral tetracycline for treating cerebral malaria.

A total of 141 cases of strictly defined cerebral malaria were studied in a controlled trial of three regimens: (1) intramuscular artemether plus oral mefloquine, (2) intravenous artesunate plus oral mefloquine, and (3) intravenous quinine (with or without an initial loading dose) plus oral tetracycline. The overall mortalities in each group were 14%, 8.3% and 34.3% respectively. The average parasite clearance time was 27.30 +/- 19.62 hours in regimen 1, 41.84 +/- 17.55 hours in regimen 2, and 47.30 +/- 21.95 hours in regimen 3. No recrudescence was observed in regimens 1 and 2, but 12.1% recrudesced in the third.