Publications by authors named "Rademaker K"

Neurological and psychiatric disorders, including substance use disorders, share a range of symptoms, which could be the result of shared genetic background. Many genetic loci have been identified for these disorders using genome-wide association studies, but conclusive evidence about cell types wherein these loci are active is lacking. We aimed to uncover implicated brain cell types in neuropsychiatric traits and to assess consistency in results across RNA datasets and methods.

View Article and Find Full Text PDF

Hepatitis B virus (HBV) has been infecting humans for millennia and remains a global health problem, but its past diversity and dispersal routes are largely unknown. We generated HBV genomic data from 137 Eurasians and Native Americans dated between ~10,500 and ~400 years ago. We date the most recent common ancestor of all HBV lineages to between ~20,000 and 12,000 years ago, with the virus present in European and South American hunter-gatherers during the early Holocene.

View Article and Find Full Text PDF

Objective: Paroxysmal epileptiform abnormalities on electroencephalography (EEG) are the hallmark of epilepsies, but it is uncertain to what extent epilepsy and background EEG oscillations share neurobiological underpinnings. Here, we aimed to assess the genetic correlation between epilepsy and background EEG oscillations.

Methods: Confounding factors, including the heterogeneous etiology of epilepsies and medication effects, hamper studies on background brain activity in people with epilepsy.

View Article and Find Full Text PDF

Objectives: Cuncaicha, a rockshelter site in the southern Peruvian Andes, has yielded archaeological evidence for human occupation at high elevation (4,480 masl) during the Terminal Pleistocene (12,500-11,200 cal BP), Early Holocene (9,500-9,000 cal BP), and later periods. One of the excavated human burials (Feature 15-06), corresponding to a middle-aged female dated to ~8,500 cal BP, exhibits skeletal osteoarthritic lesions previously proposed to reflect habitual loading and specialized crafting labor. Three small tools found in association with this burial are hypothesized to be associated with precise manual dexterity.

View Article and Find Full Text PDF

There are many unanswered questions about the population history of the Central and South Central Andes, particularly regarding the impact of large-scale societies, such as the Moche, Wari, Tiwanaku, and Inca. We assembled genome-wide data on 89 individuals dating from ∼9,000-500 years ago (BP), with a particular focus on the period of the rise and fall of state societies. Today's genetic structure began to develop by 5,800 BP, followed by bi-directional gene flow between the North and South Highlands, and between the Highlands and Coast.

View Article and Find Full Text PDF

Importance: Dexamethasone initiated after the first week of life reduces the rate of death or bronchopulmonary dysplasia (BPD) but may cause long-term adverse effects in very preterm infants. Hydrocortisone is increasingly used as an alternative, but evidence supporting its efficacy and safety is lacking.

Objective: To assess the effect of hydrocortisone initiated between 7 and 14 days after birth on death or BPD in very preterm infants.

View Article and Find Full Text PDF

We report genome-wide ancient DNA from 49 individuals forming four parallel time transects in Belize, Brazil, the Central Andes, and the Southern Cone, each dating to at least ∼9,000 years ago. The common ancestral population radiated rapidly from just one of the two early branches that contributed to Native Americans today. We document two previously unappreciated streams of gene flow between North and South America.

View Article and Find Full Text PDF

Gonadotropin-releasing hormone (GnRH) is a 10-residue peptide hormone that induces secretion of luteinizing hormone (LH) and follicle-stimulating hormone into the blood from the pituitary gland. In males, LH acts on the testes to produce testosterone. The performance-enhancing potential of testosterone makes administration of exogenous GnRH a concern in sports doping control.

View Article and Find Full Text PDF

Background: Midazolam is used as an anticonvulsant in neonatology, including newborns with perinatal asphyxia treated with hypothermia. Hypothermia may affect the safety and effectiveness of midazolam in these patients.

Objectives: The objective was to evaluate the anticonvulsant effectiveness and hemodynamic safety of midazolam in hypothermic newborns and to provide dosing guidance.

View Article and Find Full Text PDF

Study of human adaptation to extreme environments is important for understanding our cultural and genetic capacity for survival. The Pucuncho Basin in the southern Peruvian Andes contains the highest-altitude Pleistocene archaeological sites yet identified in the world, about 900 meters above confidently dated contemporary sites. The Pucuncho workshop site [4355 meters above sea level (masl)] includes two fishtail projectile points, which date to about 12.

View Article and Find Full Text PDF

The Younger Dryas Stadial (YDS; ∼ 12,900-11,600 y ago) in the Northern Hemisphere is classically defined by abrupt cooling and renewed glaciation during the last glacial-interglacial transition. Although this event involved a global reorganization of atmospheric and oceanic circulation [Denton GH, Alley RB, Comer GC, Broecker WS (2005) Quat Sci Rev 24:1159-1182], the magnitude, seasonality, and geographical footprint of YDS cooling remain unresolved and pose a challenge to our understanding of abrupt climate change. Here, we present a deglacial chronology from Scotland, immediately downwind of the North Atlantic Ocean, indicating that the Scottish ice cap disintegrated during the first half of the YDS.

View Article and Find Full Text PDF

Aim: The aim of the study was to compare clinical and neuroimaging characteristics and neurodevelopmental outcome in preterm infants with a periventricular haemorrhagic infarction (PVHI) located in the temporal or frontal periventricular white matter.

Method: The study was a retrospective hospital-based study of preterm infants with a frontal PVHI (n=21; 11 males, 10 females; mean birthweight 1527g; mean gestational age 30.3wks) or temporal PVHI (n=13; five males, eight females; mean birthweight 1205g; mean gestational age 30.

View Article and Find Full Text PDF

Objective: To assess whether there was an adverse effect on brain growth after hydrocortisone (HC) treatment for bronchopulmonary dysplasia (BPD) in a large cohort of infants without dexamethasone exposure.

Study Design: Infants who received HC for BPD between 2005 and 2011 and underwent magnetic resonance imaging at term-equivalent age were included. Control infants born in Geneva (2005-2006) and Utrecht (2007-2011) were matched to the infants treated with HC according to segmentation method, sex, and gestational age.

View Article and Find Full Text PDF

Background/Objective. Hydrocortisone, administered to ventilated preterm neonates to facilitate extubation, has no adverse long-term effects, but short-term pulmonary effects have not been described previously. In the present study, we analyzed effects of hydrocortisone on ventilator settings and FiO(2) in ventilator-dependent preterm infants.

View Article and Find Full Text PDF

Background: Randomized controlled trials have shown that treatment of chronically ventilated preterm infants after the first week of life with dexamethasone reduces the incidence of the combined outcome death or bronchopulmonary dysplasia (BPD). However, there are concerns that dexamethasone may increase the risk of adverse neurodevelopmental outcome. Hydrocortisone has been suggested as an alternative therapy.

View Article and Find Full Text PDF

Unlabelled: Germinal matrix-intraventricular haemorrhage and subsequent post-haemorrhagic ventricular dilatation (PHVD) are frequently encountered complications in preterm neonates. As progressive dilatation of the lateral ventricles may be associated with elevated intracranial pressure, ultrasound measurements of ventricular size play a major role in the evaluation of neonates at risk of ventricular dilatation as well as in assessing the effect of intervention for PHVD. A systematic search was carried out in Medline and Embase to identify neonatal and foetal ultrasound studies on lateral ventricular size.

View Article and Find Full Text PDF

Despite modern perinatal intensive care techniques, chronic lung disease remains a problem in preterm-born infants. The most commonly and almost exclusively prescribed drug to treat this disorder is dexamethasone. Corticosteroids improve short-term respiratory function; however, many side-effects have been reported and the adverse long-term effects of dexamethasone on neurodevelopment are particularly alarming.

View Article and Find Full Text PDF

We present an experimental study on the drilling of metal targets with ultrashort laser pulses at high repetition rates (from 50 kHz up to 975 kHz) and high average powers (up to 68 Watts), using an ytterbium-doped fiber CPA system. The number of pulses to drill through steel and copper sheets with thicknesses up to 1 mm have been measured as a function of the repetition rate and the pulse energy. Two distinctive effects, influencing the drilling efficiency at high repetition rates, have been experimentally found and studied: particle shielding and heat accumulation.

View Article and Find Full Text PDF

Objective: To evaluate the neurodevelopmental outcome of preterm infants with a grade III or IV hemorrhage and to assess the effect of routine low-threshold therapy of post-hemorrhagic ventricular dilatation (PHVD) on neurodevelopmental outcome.

Study Design: Of the 214 preterm infants (< or = 34 weeks gestational age), 94 (44%) had a grade III intraventricular hemorrhage (IVH), and 120 (56%) had a grade IV hemorrhage. We evaluated the natural evolution of IVH, the need for intervention for PHVD, and neurodevelopmental outcome at 24 months corrected age.

View Article and Find Full Text PDF

Magnetic resonance imaging studies have contributed to recognize the patterns of cerebral injury related to neonatal encephalopathy (NE). We assessed whether a smaller corpus callosum (CC) explained the difference in motor performance between school-age children with NE and controls. Frontal, middle, and posterior areas of the CC were measured in 61 9-10-y-old children with NE and in 47 controls.

View Article and Find Full Text PDF

The benefits versus the risks of postnatal administration of steroids in preterm-born infants are still debatable. This review examines the literature on postnatal hydrocortisone treatment for chronic lung disease (CLD) in preterm-born infants with a particular focus on the effects of such treatment on long-term neurodevelopmental outcomes. Quantitative published evidence does not point to a clear advantage of treatment with hydrocortisone over dexamethasone with regard to the impact on long-term neurological outcomes.

View Article and Find Full Text PDF

We report on an ytterbium-doped fiber based chirped-pulse amplification system delivering 100 microJ pulse energy at a repetition rate of 900 kHz, corresponding to an average power of 90 W. The emitted pulses are as short as 500 fs. To the best of our knowledge, this is the highest average power ever reported for high-energy femtosecond solid-state laser systems.

View Article and Find Full Text PDF

We report on a Q-switched short-length fiber laser producing 100 W of average output power at 100 kHz repetition rate and pulse durations as short as 17 ns. Up to 2 mJ of energy and sub-10-ns pulse duration are extracted at lower repetition rates. This performance is obtained by employing a rod-type ytterbium-doped photonic crystal fiber with a 70 microm core as gain medium, allowing for very short pulse durations, high energy storage, and emission of a single-transverse-mode beam.

View Article and Find Full Text PDF

Objective: To investigate neurodevelopment at school age in preterm infants treated with hydrocortisone for bronchopulmonary dysplasia (BPD) in the neonatal period.

Study Design: Preterm infants (n = 226; gestational age < or = 32 weeks and/or body weight < or = 1500 grams) performed subtests of the Wechsler Intelligence Scale for Children-Revised, the Visual Motor Integration test, a 15-Word Memory Test and the Movement Assessment Battery for Children at school age. Conventional MRI of the brain was obtained.

View Article and Find Full Text PDF