The asparagus genome sheds light on the origin and evolution of a young Y chromosome

Several models have been proposed to explain the emergence of sex chromosomes. Here, through comparative genomics and mutant analysis, Harkess et al. show that linked but separate genes on the Y chromosome are responsible for sex determination in Asparagus, supporting a two-gene model for sex chromosome evolution

Sunfish Amphiphiles: Conceptually New Carriers for DNA Delivery

A conceptually new class of cationic amphiphiles, Sunfish amphiphiles, designed for the delivery of genes into cells is introduced. Sunfish amphiphiles have two hydrophobic tails, connected at the 4- and the N-position to the cationic pyridinium headgroup. Two extreme morphologies visualised by backfolding and combining of both tails at one site (matching situation) or unfolding of the tails at distinct interaction sites at biological membranes will lead to considerable differences in morphological behaviour. The underlying rationale allows controlled release by using this morphological alteration of the Sunfish/helper-lipid/DNA complex (lipoplex). The often-excellent transfection efficiencies are probably related to these morphological changes. In addition, the Sunfish amphiphiles possess low toxicities, resulting in high cell survival after internalisation. The underlying rationale, design, synthesis and in vitro transfection potential are discussed in detail. Moreover, some physico-chemical characteristics of the Sunfish amphiphiles have been studied.

Lower versus Traditional Treatment Threshold for Neonatal Hypoglycemia

BACKGROUND Worldwide, many newborns who are preterm, small or large for gestational age, or born to mothers with diabetes are screened for hypoglycemia, with a goal of preventing brain injury. However, there is no consensus on a treatment threshold that is safe but also avoids overtreatment. METHODS In a multicenter, randomized, noninferiority trial involving 689 otherwise healthy newborns born at 35 weeks of gestation or later and identified as being at risk for hypoglycemia, we compared two threshold values for treatment of asymptomatic moderate hypoglycemia. We sought to determine whether a management strategy that used a lower threshold (treatment administered at a glucose concentration of <36 mg per deciliter [2.0 mmol per liter]) would be noninferior to a traditional threshold (treatment at a glucose concentration of <47 mg per deciliter [2.6 mmol per liter]) with respect to psychomotor development at 18 months, assessed with the Bayley Scales of Infant and Toddler Development, third edition, Dutch version (Bayley-III-NL; scores range from 50 to 150 [mean {±SD}, 100±15]), with higher scores indicating more advanced development and 7.5 points (one half the SD) representing a clinically important difference). The lower threshold would be considered noninferior if scores were less than 7.5 points lower than scores in the traditional-threshold group. RESULTS Bayley-III-NL scores were assessed in 287 of the 348 children (82.5%) in the lower-threshold group and in 295 of the 341 children (86.5%) in the traditional-threshold group. Cognitive and motor outcome scores were similar in the two groups (mean scores [±SE], 102.9±0.7 [cognitive] and 104.6±0.7 [motor] in the lower-threshold group and 102.2±0.7 [cognitive] and 104.9±0.7 [motor] in the traditional-threshold group). The prespecified inferiority limit was not crossed. The mean glucose concentration was 57±0.4 mg per deciliter (3.2±0.02 mmol per liter) in the lower-threshold group and 61±0.5 mg per deciliter (3.4±0.03 mmol per liter) in the traditional-threshold group. Fewer and less severe hypoglycemic episodes occurred in the traditional-threshold group, but that group had more invasive diagnostic and treatment interventions. Serious adverse events in the lower-threshold group included convulsions (during normoglycemia) in one newborn and one death. CONCLUSIONS In otherwise healthy newborns with asymptomatic moderate hypoglycemia, a lower glucose treatment threshold (36 mg per deciliter) was noninferior to a traditional threshold (47 mg per deciliter) with regard to psychomotor development at 18 months. (Funded by the Netherlands Organization for Health Research and Development; HypoEXIT Current Controlled Trials number, ISRCTN79705768. opens in new tab.

Amsterdam Acute Aneurysm Trial: Background, design, and methods

The objective of the Amsterdam Acute Aneurysm Trial is to study the combined outcome of conventional emergency surgery versus endovascular treatment for ruptured abdominal aortic aneurysms. The design used was a multicenter randomized clinical trial conducted in two university hospitals and one teaching hospital in the Amsterdam region. The study included all patients with a ruptured abdominal aneurysm who were eligible for endovascular and conventional surgery. The primary end points were combined mortality and severe morbidity. The secondary end points were quality of life and cost-effectiveness. The background, design, and methods of this trial are presented, and the ethical and legal issues of this type of research are discussed

Lower versus Traditional Treatment Threshold for Neonatal Hypoglycemia

BACKGROUND Worldwide, many newborns who are preterm, small or large for gestational age, or born to mothers with diabetes are screened for hypoglycemia, with a goal of preventing brain injury. However, there is no consensus on a treatment threshold that is safe but also avoids overtreatment. METHODS In a multicenter, randomized, noninferiority trial involving 689 otherwise healthy newborns born at 35 weeks of gestation or later and identified as being at risk for hypoglycemia, we compared two threshold values for treatment of asymptomatic moderate hypoglycemia. We sought to determine whether a management strategy that used a lower threshold (treatment administered at a glucose concentration of <36 mg per deciliter [2.0 mmol per liter]) would be noninferior to a traditional threshold (treatment at a glucose concentration of <47 mg per deciliter [2.6 mmol per liter]) with respect to psychomotor development at 18 months, assessed with the Bayley Scales of Infant and Toddler Development, third edition, Dutch version (Bayley-III-NL; scores range from 50 to 150 [mean {±SD}, 100±15]), with higher scores indicating more advanced development and 7.5 points (one half the SD) representing a clinically important difference). The lower threshold would be considered noninferior if scores were less than 7.5 points lower than scores in the traditional-threshold group. RESULTS Bayley-III-NL scores were assessed in 287 of the 348 children (82.5%) in the lower-threshold group and in 295 of the 341 children (86.5%) in the traditional-threshold group. Cognitive and motor outcome scores were similar in the two groups (mean scores [±SE], 102.9±0.7 [cognitive] and 104.6±0.7 [motor] in the lower-threshold group and 102.2±0.7 [cognitive] and 104.9±0.7 [motor] in the traditional-threshold group). The prespecified inferiority limit was not crossed. The mean glucose concentration was 57±0.4 mg per deciliter (3.2±0.02 mmol per liter) in the lower-threshold group and 61±0.5 mg per deciliter (3.4±0.03 mmol per liter) in the traditional-threshold group. Fewer and less severe hypoglycemic episodes occurred in the traditional-threshold group, but that group had more invasive diagnostic and treatment interventions. Serious adverse events in the lower-threshold group included convulsions (during normoglycemia) in one newborn and one death. CONCLUSIONS In otherwise healthy newborns with asymptomatic moderate hypoglycemia, a lower glucose treatment threshold (36 mg per deciliter) was noninferior to a traditional threshold (47 mg per deciliter) with regard to psychomotor development at 18 months. (Funded by the Netherlands Organization for Health Research and Development; HypoEXIT Current Controlled Trials number, ISRCTN79705768.)

The asparagus genome sheds light on the origin and evolution of a young Y chromosome

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution

The asparagus genome sheds light on the origin and evolution of a young Y chromosome

Sex chromosomes evolved from autosomes many times across the eukaryote phylogeny. Several models have been proposed to explain this transition, some involving male and female sterility mutations linked in a region of suppressed recombination between X and Y (or Z/W, U/V) chromosomes. Comparative and experimental analysis of a reference genome assembly for a double haploid YY male garden asparagus (Asparagus officinalis L.) individual implicates separate but linked genes as responsible for sex determination. Dioecy has evolved recently within Asparagus and sex chromosomes are cytogenetically identical with the Y, harboring a megabase segment that is missing from the X. We show that deletion of this entire region results in a male-to-female conversion, whereas loss of a single suppressor of female development drives male-to-hermaphrodite conversion. A single copy anther-specific gene with a male sterile Arabidopsis knockout phenotype is also in the Y-specific region, supporting a two-gene model for sex chromosome evolution