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1.
Pediatr Neurol ; 151: 90-95, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38141554

ABSTRACT

BACKGROUND: Changes in residency recruitment have significantly altered how programs and applicants evaluate each other including virtual interviews, discontinuation of the United States Medical Licensing Exam Step 2 Clinical Skills exam, and transition of United States Medical Licensing Exam Step 1 to pass-fail scoring. To improve program-applicant fit, the Electronic Residency Application Service introduced supplemental application features including geographic preference, program signaling, and the opportunity to highlight impactful and meaningful experiences. We sought to evaluate child neurology (CN) and neurodevelopmental disabilities (NDD) program director's (PD) opinions regarding these changes. METHODS: A 10-question anonymous survey was sent to CN (n=75) and NDD (n=8) PDs. The questions centered on PDs' opinions regarding components of the supplemental application, having a standard application review period and in-person recruitment activities. Answer choices to the questions were all close-ended. Respondents could select questions to complete. RESULTS: Thirty-eight CN residency PDs (49%) and 4 NDD residency PDs (50%) responded to the survey. Among CN PDs, there was strong support for use of the supplemental application questions and for the use of 3 program signals per applicant. Most PDs supported a standardized application review period prior to programs sending interview offers; however, there was no consensus on the appropriate length of time. Nearly half agreed with virtual-only interviews, and 62% agreed with the option of in-person second-look visits. CONCLUSIONS: CN PDs generally support many of the recent or proposed changes to residency recruitment. The impact of these changes on recruitment will be a topic of future investigation.


Subject(s)
Internship and Residency , Neurology , Humans , Consensus , Personnel Selection , Surveys and Questionnaires , United States
2.
Pediatrics ; 152(2)2023 08 01.
Article in English | MEDLINE | ID: mdl-37465909

ABSTRACT

Guanidinoacetate methyltransferase (GAMT) deficiency is an autosomal recessive disorder of creatine biosynthesis due to pathogenic variants in the GAMT gene that lead to cerebral creatine deficiency and neurotoxic levels of guanidinoacetate. Untreated, GAMT deficiency is associated with hypotonia, significant intellectual disability, limited speech development, recurrent seizures, behavior problems, and involuntary movements. The birth prevalence of GAMT deficiency is likely between 0.5 and 2 per million live births. On the basis of small case series and sibling data, presymptomatic treatment with oral supplements of creatine, ornithine, and sodium benzoate, and a protein-restricted diet to reduce arginine intake, appear to substantially improve health and developmental outcomes. Without newborn screening, diagnosis typically happens after the development of significant impairment, when treatment has limited utility. GAMT deficiency newborn screening can be incorporated into the tandem-mass spectrometry screening that is already routinely used for newborn screening, with about 1 per 100 000 newborns screening positive. After a positive screen, diagnosis is established by finding an elevated guanidinoacetate concentration and low creatine concentration in the blood. Although GAMT deficiency is significantly more rare than other conditions included in newborn screening, the feasibility of screening, the low number of positive results, the relative ease of diagnosis, and the expected benefit of presymptomatic dietary therapy led to a recommendation from the Advisory Committee on Heritable Disorders in Newborns and Children to the Secretary of Health and Human Services that GAMT deficiency be added to the Recommended Uniform Screening Panel. This recommendation was accepted in January 2023.


Subject(s)
Language Development Disorders , Movement Disorders , Child , Humans , Infant, Newborn , Guanidinoacetate N-Methyltransferase/genetics , Creatine , Neonatal Screening/methods , Language Development Disorders/diagnosis , Movement Disorders/diagnosis , Movement Disorders/genetics , Movement Disorders/therapy
3.
Genet Med ; 25(2): 100330, 2023 02.
Article in English | MEDLINE | ID: mdl-36445366

ABSTRACT

Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is an X-linked condition caused by pathogenic variants in the iduronate-2-sulfatase gene. The resulting reduced activity of the enzyme iduronate-2-sulfatase leads to accumulation of glycosaminoglycans that can progressively affect multiple organ systems and impair neurologic development. In 2006, the US Food and Drug Administration approved idursulfase for intravenous enzyme replacement therapy for MPS II. After the data suggesting that early treatment is beneficial became available, 2 states, Illinois and Missouri, implemented MPS II newborn screening. Following a recommendation of the Advisory Committee on Heritable Disorders in Newborns and Children in February 2022, in August 2022, the US Secretary of Health and Human Services added MPS II to the Recommended Uniform Screening Panel, a list of conditions recommended for newborn screening. MPS II was added to the Recommended Uniform Screening Panel after a systematic evidence review reported the accuracy of screening, the benefit of presymptomatic treatment compared with usual case detection, and the feasibility of implementing MPS II newborn screening. This manuscript summarizes the findings of the evidence review that informed the Advisory Committee's decision.


Subject(s)
Iduronate Sulfatase , Mucopolysaccharidosis II , Child , Humans , Infant, Newborn , United States , Mucopolysaccharidosis II/diagnosis , Mucopolysaccharidosis II/genetics , Neonatal Screening , Iduronic Acid , Iduronate Sulfatase/therapeutic use , Glycosaminoglycans , Enzyme Replacement Therapy/methods
4.
Semin Pediatr Neurol ; 42: 100977, 2022 07.
Article in English | MEDLINE | ID: mdl-35868726

ABSTRACT

The severe acute respiratory syndrome coronavirus 2 pandemic has markedly, and likely permanently, changed health care. This includes changing the obstetric and perinatal care of mothers and infants, and by extension, the care of their families. Infection during pregnancy is associated with an increased risk for severe coronavirus disease 2019 illness and related complications that can significantly impact maternal health and the health of the neonate. Viral transmission from mother to fetus is possible, but rare during pregnancy, and current health care policies focusing on maternal masking, and hand washing allows infected mothers to safely care for neonates (including nursing or feeding with expressed breast milk). The newly developed vaccines have been shown to be safe and effective for pregnant and breast-feeding mothers, with measurable antibody levels in cord blood and breast milk potentially providing a level of passive immunity to neonates. While studies looking at short-term outcomes for neonates have been reassuring, it is critical that we continue to work to understand and improve the care of pregnant woman and newborns with coronavirus disease 2019 to optimize long term outcomes. Although the knowledge base continues to evolve, the available evidence influencing the care of pregnant women and their infants is summarized in this focused review.


Subject(s)
COVID-19 , Pregnancy Complications, Infectious , Female , Humans , Infant , Infant, Newborn , Infectious Disease Transmission, Vertical/prevention & control , Mothers , Pandemics , Pregnancy , Pregnancy Complications, Infectious/epidemiology , Pregnancy Complications, Infectious/prevention & control
5.
Semin Pediatr Neurol ; 42: 100978, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35868727
6.
Semin Pediatr Neurol ; 42: 100957, 2022 07.
Article in English | MEDLINE | ID: mdl-35868732

ABSTRACT

Fetal and neonatal neurology is increasingly recognized as a subspecialty within child neurology and fellowship training programs are emerging. Most child neurologists have not received formal training in the interpretation of fetal data and the practice of fetal neurology consultation. However, they can be valuable members of the fetal care team and bring important perspective to the diagnosis of fetal neurologic conditions. With a systematic approach and a planned format for counseling, child neurologists without formal training in fetal consultations can apply their postnatal neurology expertise to the prenatal neurology patient. In this article we offer a brief practical guide to assist child neurologists in their approach to and practice of fetal neurology consultation.


Subject(s)
Fetal Diseases , Nervous System Diseases , Neurology , Female , Humans , Infant, Newborn , Neurologists , Referral and Consultation
7.
Blood Adv ; 6(9): 2947-2956, 2022 05 10.
Article in English | MEDLINE | ID: mdl-35042231

ABSTRACT

Infantile Krabbe disease (IKD) can be treated with hematopoietic cell transplantation (HCT) if done during the first weeks of life before symptoms develop. To facilitate this, newborn screening (NBS) has been instituted in 8 US states. An application to add IKD to the recommended NBS panel is currently under review. In this report, the outcomes of newborns with IKD diagnosed through NBS and treated with HCT are presented. The unique challenges associated with NBS for this disease are discussed, including opportunities for earlier diagnosis and streamlining treatment referrals. This is a retrospective review of six infants with IKD detected by NBS who were referred for HCT. The timing from diagnosis to HCT was examined, and both HCT and neurodevelopmental outcomes are described. Neurologic testing before HCT revealed evidence of active IKD in all infants. All underwent HCT between 24 and 40 days of age, were successfully engrafted, and are alive 30 to 58 months later (median, 47.5 months). All are gaining developmental milestones albeit at a slower pace than unaffected age-matched peers. Gross motor function is most notably affected. NBS for these patients enabled early access to HCT, the only currently available treatment of infants with IKD. All children are alive and have derived developmental and neurologic benefits from timely HCT. Long-term follow up is ongoing. Optimization of HCT and further development of emerging therapies, all of which must be delivered early in life, are expected to further improve outcomes of infants with IKD.


Subject(s)
Hematopoietic Stem Cell Transplantation , Leukodystrophy, Globoid Cell , Child , Child, Preschool , Humans , Infant , Infant, Newborn , Leukodystrophy, Globoid Cell/diagnosis , Leukodystrophy, Globoid Cell/therapy , Longitudinal Studies , Neonatal Screening
8.
Pediatr Neurol ; 126: 3-8, 2022 01.
Article in English | MEDLINE | ID: mdl-34688202

ABSTRACT

BACKGROUND: The COVID-19 pandemic presented many challenges for graduate medical education, including the need to quickly implement virtual residency interviews. We investigated how different programs approached these challenges to determine best practices. METHODS: Surveys to solicit perspectives of program directors, program coordinators, and chief residents regarding virtual interviews were designed through an iterative process by two child neurology residency program directors. Surveys were distributed by email in May 2021. Results were summarized using descriptive statistics. RESULTS: Responses were received from 35 program directors and 34 program coordinators from 76 programs contacted. Compared with the 2019-2020 recruitment season, in 2020-2021, 14 of 35 programs received >10% more applications and most programs interviewed ≥12 applicants per position. Interview days were typically five to six hours long and were often coordinated with pediatrics interviews. Most programs (13/15) utilized virtual social events with residents, but these often did not allow residents to provide quality feedback about applicants. Program directors could adequately assess most applicant qualities but felt that virtual interviews limited their ability to assess applicants' interpersonal communication skills and to showcase special features of their programs. Most respondents felt that a combination of virtual and in-person interviewing should be utilized in the future. CONCLUSIONS: Residency program directors perceived some negative impacts of virtual interviewing on their recruitment efforts but in general felt that virtual interviews adequately replaced in-person interviews for assessing applicants. Most programs felt that virtual interviewing should be utilized in the future.


Subject(s)
Education, Medical, Graduate , Internship and Residency , Interviews as Topic , Neurology/education , Pediatrics/education , Videoconferencing , Attitude of Health Personnel , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/transmission , Communicable Disease Control , Humans , School Admission Criteria , Surveys and Questionnaires
9.
Mol Genet Metab ; 134(1-2): 53-59, 2021.
Article in English | MEDLINE | ID: mdl-33832819

ABSTRACT

OBJECTIVE: To provide updated evidence and consensus-based recommendations for the classification of individuals who screen positive for Krabbe Disease (KD) and recommendations for long-term follow-up for those who are at risk for late onset Krabbe Disease (LOKD). METHODS: KD experts (KD NBS Council) met between July 2017 and June 2020 to develop consensus-based classification and follow-up recommendations. The resulting newly proposed recommendations were assessed in a historical cohort of 47 newborns from New York State who were originally classified at moderate or high risk for LOKD. RESULTS: Infants identified by newborn screening with possible KD should enter one of three clinical follow-up pathways (Early infantile KD, at-risk for LOKD, or unaffected), based on galactocerebrosidase (GALC) activity, psychosine concentration, and GALC genotype. Patients considered at-risk for LOKD based on low GALC activity and an intermediate psychosine concentration are further split into a high-risk or low-risk follow-up pathway based on genotype. Review of the historical New York State cohort found that the updated follow-up recommendations would reduce follow up testing by 88%. CONCLUSION: The KD NBS Council has presented updated consensus recommendations for efficient and effective classification and follow-up of NBS positive patients with a focus on long-term follow-up of those at-risk for LOKD.


Subject(s)
Consensus , Genotype , Leukodystrophy, Globoid Cell/classification , Leukodystrophy, Globoid Cell/genetics , Neonatal Screening/methods , Practice Guidelines as Topic , Dried Blood Spot Testing , Follow-Up Studies , Humans , Infant , Infant, Newborn , Late Onset Disorders/diagnosis , Late Onset Disorders/etiology , Late Onset Disorders/genetics , Leukodystrophy, Globoid Cell/diagnosis , Risk Factors
10.
Semin Pediatr Neurol ; 37: 100876, 2021 04.
Article in English | MEDLINE | ID: mdl-33892849

ABSTRACT

Leukodystrophies and genetic leukoencephalopathies comprise a growing group of inherited white matter disorders. Diagnostic rates have improved with increased utilization of next generation sequencing. As treatment options continue to advance for leukodystrophies, so will candidacy for inclusion in the United States' newborn Recommended Universal Screening Panel as was achieved for X-linked adrenoleukodystrophy. Stem cell therapies have become standard of care for selected leukodystrophies. However, transplantation-related risks remain high and outcomes are not fully satisfactory. Transduction of autologous hematopoietic stem cells with lentiviral vectors, referred to as ex vivo gene therapy, circumvents some, but not all, of the risks of traditional transplantation and has recently been demonstrated to be safe and efficective in clinical studies of X-linked adrenoleukodystrophy and metachromatic leukodystrophy. Gene therapy, through direct infusion of adeno-associated virus vectors, has emerged as a safer alternative for many monogenetic pediatric neurological disorders. Numerous preclinical studies have shown safety and efficacy of adeno-associated virus gene therapy in leukodystrophies allowing expanded access treatment for Canavan disease prior to initiation of a clinical trial. For inherited white matter disorders resulting from overexpression of a protein, such as Pelizaeus-Merzbacher disease, emerging RNA therapies have shown success in preclinical studies and promise for rapid translation to the clinic. Lastly, small molecule and protein therapies remain a long-term treatment option for a number of leukodystrophies, including intrathecal enzyme replacement therapy for metachromatic leukodystrophy. Herein we review recent advances in diagnosis and treatment of inherited white matter disorders.


Subject(s)
Demyelinating Diseases , Leukodystrophy, Metachromatic , Leukoencephalopathies , Neurodegenerative Diseases , Child , Genetic Therapy , Humans , Leukodystrophy, Metachromatic/diagnosis , Leukodystrophy, Metachromatic/genetics , Leukodystrophy, Metachromatic/therapy , Leukoencephalopathies/therapy
11.
Genet Med ; 22(6): 1108-1118, 2020 06.
Article in English | MEDLINE | ID: mdl-32089546

ABSTRACT

PURPOSE: Newborn screening (NBS) for Krabbe disease (KD) is performed by measurement of galactocerebrosidase (GALC) activity as the primary test. This revealed that GALC activity has poor specificity for KD. Psychosine (PSY) was proposed as a disease marker useful to reduce the false positive rate for NBS and for disease monitoring. We report a highly sensitive PSY assay that allows identification of KD patients with minimal PSY elevations. METHODS: PSY was extracted from dried blood spots or erythrocytes with methanol containing d5-PSY as internal standard, and measured by liquid chromatography-tandem mass spectrometry. RESULTS: Analysis of PSY in samples from controls (N = 209), GALC pseudodeficiency carriers (N = 55), GALC pathogenic variant carriers (N = 27), patients with infantile KD (N = 26), and patients with late-onset KD (N = 11) allowed for the development of an effective laboratory screening and diagnostic algorithm. Additional longitudinal measurements were used to track therapeutic efficacy of hematopoietic stem cell transplantion (HSCT). CONCLUSION: This study supports PSY quantitation as a critical component of NBS for KD. It helps to differentiate infantile from later onset KD variants, as well as from GALC variant and pseudodeficiency carriers. Additionally, this study provides further data that PSY measurement can be useful to monitor KD progression before and after treatment.


Subject(s)
Leukodystrophy, Globoid Cell , Psychosine , Dried Blood Spot Testing , Galactosylceramidase/genetics , Humans , Infant, Newborn , Leukodystrophy, Globoid Cell/diagnosis , Leukodystrophy, Globoid Cell/genetics , Neonatal Screening
12.
Curr Treat Options Neurol ; 21(2): 8, 2019 Feb 18.
Article in English | MEDLINE | ID: mdl-30773607

ABSTRACT

PURPOSE OF REVIEW: The purpose of this review is to report recent advances in treatment of neonatal seizures, with a specific focus on new literature since a 2013 systematic review performed by this author (Slaughter) and others. There is a paucity of data with regard to well-defined status epilepticus (SE) in neonates, so treatment of recurrent seizures was also included in this inquiry. We aimed to summarize the efficacy and safety profiles of current therapeutic options as well as describe trends in medication selection in the neonatal intensive care unit (NICU) setting. RECENT FINDINGS: Phenobarbital remains first-line therapy in practice, though there is increasing evidence of its neurotoxicity and long-term sequelae. Bumetanide failed an open-label trial for efficacy, demonstrated an increased risk for hearing loss, and has since fallen out of favor for use in this population. New agents, such as levetiracetam and topiramate, still have very limited data but appear to be as efficacious as older medications, with more favorable side effect profiles. There are limited high-level evidence-based data to guide treatment of neonatal seizures. Emerging research focusing on drug mechanisms and safety profiles may provide additional information to guide decisions; however, further research is needed.

13.
Semin Pediatr Neurol ; 26: 92-93, 2018 07.
Article in English | MEDLINE | ID: mdl-29961531

ABSTRACT

Vague complaints of ear pain can bring frustration in the neurology office as the differential is broad and often nonneurologic. Herein, we present a case of red ear syndrome, a treatable migraine variant that can cause significant distress and lead to delayed treatment if not considered as a diagnostic possibility.


Subject(s)
Ear/pathology , Migraine Disorders/diagnosis , Migraine Disorders/pathology , Pain/diagnosis , Pain/pathology , Child , Diagnosis, Differential , Ear/physiopathology , Humans , Male , Migraine Disorders/drug therapy , Migraine Disorders/physiopathology , Pain/drug therapy , Pain/physiopathology
14.
Curr Neurol Neurosci Rep ; 18(8): 48, 2018 06 16.
Article in English | MEDLINE | ID: mdl-29907917

ABSTRACT

PURPOSE OF REVIEW: Preterm birth is the leading cause of death worldwide in children < 5 years of age; however, technology and advances in medical knowledge are increasing the survival of children born even at the fringes of viability. With increased survival comes increased risk of long-term neurologic impairments. This paper aims to review recent findings related to changes in brain development associated with prematurity and its impact on neurodevelopmental disabilities. RECENT FINDINGS: Advanced imaging techniques, longitudinal follow-up of individuals born extremely preterm into adulthood and improved understanding of risk factors associated with neurologic impairment contribute to recent discoveries. Sensory impairments are often associated with later cognitive and social impairments and therefore represent targets for therapy. All aspects of neurologic development can be affected by preterm delivery. Future research is needed to further elucidate targets for prenatal and postnatal interventions for neuroprotection and to improve outcomes of prematurity.


Subject(s)
Developmental Disabilities/diagnostic imaging , Nervous System Diseases/diagnostic imaging , Premature Birth/diagnostic imaging , Adult , Animals , Child , Child, Preschool , Developmental Disabilities/physiopathology , Developmental Disabilities/psychology , Female , Gestational Age , Humans , Infant, Newborn , Nervous System Diseases/physiopathology , Nervous System Diseases/psychology , Pregnancy , Premature Birth/physiopathology , Premature Birth/psychology , Risk Factors
15.
Pediatr Neurol ; 64: 6-7, 2016 11.
Article in English | MEDLINE | ID: mdl-27663489
16.
Epilepsia ; 56(10): 1505-14, 2015 Oct.
Article in English | MEDLINE | ID: mdl-26345167

ABSTRACT

The steps from patient evaluation to genetic diagnosis remain complicated. We discuss some of the genetic testing methods available along with their general advantages and disadvantages. We briefly review common pediatric epilepsy syndromes with strong genetic association and provide a potentially useful algorithm for genetic testing in drug-resistant epilepsy. We performed an extensive literature review of available information as it pertains to genetic testing and genetics in pediatric epilepsy. If a genetic disorder is suspected as the cause of epilepsy, based on drug resistance, family history, or clinical phenotype, timely diagnosis may reduce overall cost, limit the diagnostic odyssey that can bring much anxiety to families, improve prognostic accuracy, and lead to targeted therapy. Interpretation of complicated results should be performed only in collaboration with geneticists and genetic counselors, unless the ordering neurologist has a strong background in and understanding of genetics. Genetic testing can play an important role in the care provided to patients with epilepsy.


Subject(s)
Epilepsy/diagnosis , Epilepsy/genetics , Genetic Testing/methods , Pediatrics , Child , Epilepsy/classification , Humans , Methylene Blue
18.
Epilepsy Behav ; 37: 241-8, 2014 Aug.
Article in English | MEDLINE | ID: mdl-25108116

ABSTRACT

RATIONALE: The utility of genetic testing in pediatric drug-resistant epilepsy (PDRE), its yield in "real life" clinical practice, and the practical implications of such testing are yet to be determined. GOAL: To start to address the above gaps in our knowledge as they apply to a patient population seen in a tertiary care center. METHODS: We retrospectively reviewed our experience with the use of clinically available genetic tests in the diagnosis and management of PDRE in one clinic over one year. Genetic testing included, depending on clinical judgment, one or more of the following: karyotype, chromosomal microarray, single gene sequencing, gene sequencing panels, and/or whole exome sequencing (WES). RESULTS: We were more likely to perform genetic testing in patients with developmental delay, epileptic encephalopathy, and generalized epilepsy. In our unique population, the yield of specific genetic diagnosis was relatively high: karyotype 14.3%, microarray 16.7%, targeted single gene sequencing 15.4%, gene panels 46.2%, and WES 16.7%. Overall yield of diagnosis from at least one of the above tests was 34.5%. Disease-causing mutations that were not clinically suspected based on the patients' phenotypes and representing novel phenotypes were found in 6.9% (2/29), with an additional 17.2% (5/29) demonstrating pharmacologic variants. Three patients were incidentally found to be carriers of recessive neurologic diseases (10.3%). Variants of unknown significance (VUSs) were identified in 34.5% (10/29). CONCLUSIONS: We conclude that genetic testing had at least some utility in our patient population of PDRE, that future similar larger studies in various populations are warranted, and that clinics offering such tests must be prepared to address the complicated questions raised by the results of such testing.


Subject(s)
Anticonvulsants/therapeutic use , Epilepsy/drug therapy , Genetic Testing/methods , Child , Child, Preschool , Developmental Disabilities/etiology , Developmental Disabilities/genetics , Epilepsy/genetics , Epilepsy, Generalized/genetics , Female , Humans , Pediatrics , Phenotype , Pilot Projects , Retrospective Studies
19.
Pediatr Neurol ; 50(1): 101-3, 2014 Jan.
Article in English | MEDLINE | ID: mdl-24287234

ABSTRACT

BACKGROUND: Refractory status epilepticus carries a high risk of morbidity and mortality for children. Traditional treatment of status epilepticus consists of multiple anticonvulsant drugs and, if needed, induction of a medical coma. The ketogenic diet has been used for intractable epilepsy for many years. The purpose of this article is to report a case series of five patients with refractory status epilepticus successfully managed with the ketogenic diet. METHODS: A summary of pediatric patients with refractory status epilepticus treated with diet was performed. CONCLUSIONS: Ketogenic diet therapy should be considered as a treatment option in pediatric patients with refractory status epilepticus.


Subject(s)
Diet, Ketogenic/methods , Status Epilepticus/diet therapy , Child , Child, Preschool , Humans , Infant , Male
20.
Am J Physiol Regul Integr Comp Physiol ; 295(3): R942-53, 2008 Sep.
Article in English | MEDLINE | ID: mdl-18635452

ABSTRACT

The catecholamine norepinephrine is required for fetal survival, but its essential function is unknown. When catecholamine-deficient [tyrosine hydroxylase (Th) null] mouse fetuses die at embryonic day (E)13.5-14.5, they resemble wild-type (wt) fetuses exposed to hypoxia. They exhibit bradycardia (28% reduction in heart rate), thin ventricular myocardium (20% reduction in tissue), epicardial detachment, and death with vascular congestion, hemorrhage, and edema. At E12.5, before the appearance of morphological deficits, catecholamine-deficient fetuses are preferentially killed by experimentally induced hypoxia and have lower tissue Po(2) levels than wt siblings. By microarray analysis (http://www.ncbi.nlm.nih.gov/geo; accession no. GSE10341), hypoxia-inducible factor-1 target genes are induced to a greater extent in null fetuses than in wt siblings, supporting the notion that mutants experience lower oxygen tension or have an enhanced response to hypoxia. Hypoxia induces a 13-fold increase in plasma norepinephrine levels, which would be expected to increase heart rate, thereby improving oxygen delivery in wt mice. Surprisingly, increasing maternal oxygen (inspired O(2) 33 or 63%) prevents the effects of catecholamine deficiency, restoring heart rate, myocardial tissue, and survival of Th null fetuses to wt levels. We suggest that norepinephrine mediates fetal survival by maintaining oxygen homeostasis.


Subject(s)
Hypoxia/therapy , Norepinephrine/blood , Oxygen Inhalation Therapy , Oxygen/pharmacology , Tyrosine 3-Monooxygenase/genetics , Animals , Bradycardia/mortality , Bradycardia/therapy , Disease Models, Animal , Female , Fetal Death/prevention & control , Gene Expression Regulation, Developmental , Heart Rate , Hypoxia/mortality , Hypoxia-Inducible Factor 1/genetics , Hypoxia-Inducible Factor 1/metabolism , Male , Mice , Mice, Inbred Strains , Mice, Mutant Strains , Norepinephrine/deficiency , Pregnancy , Survival Rate , Tyrosine 3-Monooxygenase/metabolism
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