China
Africa
Explore chapters and articles related to this topic
Extensions of the Three PDE Chemotaxis Model
Published in William E. Schiesser, Chemotaxis Modeling of Autoimmune Inflammation, 2023
t is the current value of t in eqs. (6.3-1–6.6-3). u is the 63-vector of ODE/PDE dependent variables for nc=1, 126 for nc=2. parm is an argument to pass parameters to pde1b (unused, but required in the argument list). The arguments must be listed in the order stated to properly interface with lsodes called in the main program of Listing 6.3. The derivative vector of the LHS of eqs. (6.3-1–6.3-6), (6.5-1–6.5-6) is calculated and returned to lsodes as explained subsequently. The programming added for nc=2 is identified with (if(nc==2)).
Genetic Counseling in Assisted Reproductive Technology
Published in Carlos Simón, Carmen Rubio, Handbook of Genetic Diagnostic Technologies in Reproductive Medicine, 2022
Although carriers of a balanced chromosomal rearrangement are generally healthy, the rearrangement can cause difficulties conceiving or carrying a child to term. The most common balanced structural rearrangements are translocations, in which segments from two chromosomes dissociate and then rejoin to the reciprocal chromosome, and inversions, where a segment of a single chromosome disassociates but then rejoins in the opposite orientation. Robertsonian translocations are unique types of translocations that involve the acrocentric chromosomes 13, 14, 15, 21, and 22. The chromosomes fuse at the centromere, resulting in a reduction in the total number of chromosomes and the benign loss of the redundant stalks and satellites at the p arm of both chromosomes. A balanced chromosomal rearrangement can lead to difficulty conceiving, spontaneous miscarriage, or the birth of a child with multiple congenital anomalies, depending on the degree of the imbalance. Although balanced in the carrier, structural rearrangements may be unbalanced in the gametes, resulting in developmental abnormalities. In some individuals, the structural rearrangement can impair meiosis and block gametogenesis, especially male spermatogenesis. The disruption of spermatogenesis is variable, even among male relatives carrying the same chromosomal rearrangement. Approximately 1/500 individuals in the general population carry a balanced reciprocal translocation, and approximately 1/1000 individuals carry a balanced Robertsonian translocation. This frequency is likely to be higher in the infertile population.
Congenital Central Hypoventilation Syndrome
Published in Dongyou Liu, Handbook of Tumor Syndromes, 2020
PARM are in-frame triplet duplications involving the second polyalanine repeat in PHOX2B exon 3 that codes for 20 alanines, resulting in expansion of 4–13 additional alanine repeats. PARM occur in 90% of CCHS cases, produce a variable clinical profile, and their sizes correlate to disease severity. While individuals who have 20 alanines or fewer are unaffected, those individuals heterozygous for 24–26 GCN repeats (genotypes 20/24–26) may have a mild phenotype only (e.g., gastroesophageal reflux, constipation, cardiac arrhythmias, ocular, and endocrinological disorders) manifesting during illness or exposure to respiratory depressants, and those heterozygous for 26 to 33 GCN repeats (genotypes 20/26–33) are fully affected and often require continuous ventilatory support.
Advances in the molecular biology and pathogenesis of congenital central hypoventilation syndrome—implications for new therapeutic targets
Published in Expert Opinion on Orphan Drugs, 2018
Simona Di Lascio, Roberta Benfante, Silvia Cardani, Diego Fornasari
Wild-type PHOX2B forms homodimers in vitro and dimerization is probably required for transcriptional activation. An important fraction of the mutants with short alanine expansions retains this ability to form homodimers, but this is progressively lost by increasingly long expansions and NPARM mutants that probably form oligomers rather than dimers [62,68,70]. PARM mutants interact weakly with normal protein, and so it is unlikely that the observed dominant-negative effects are the result of direct interactions between wild-type and mutant proteins [62]; they are more probably due to aberrant interactions with other proteins such as transcriptional co-activators or co-repressors [73,74]. It is interesting to note that PHOX2B protein and its paralogue PHOX2A form heterodimers in vitro and in cell models [56,62,75] and, although PHOX2B mutants retain a partial ability to form heterodimers with PHOX2A, they do not interfere with the localization [68] and transcriptional activity of PHOX2A which, surprisingly, can synergize with PHOX2B mutants [62].
Philippine Academy of Rehabilitation Medicine emergency basic relief and medical aid mission project (November 2013–February 2014): the role of physiatrists in Super Typhoon Haiyan
Published in Disability and Rehabilitation, 2018
Filipinas Ganchoon, Rommel Bugho, Liezel Calina, Rochelle Dy, James Gosney
PARM CARES evolved administratively and operationally over the course of the three-month project. Designation as an official PARM advocacy activity facilitated mission personnel recruitment, media coverage, and fundraising. An initial operational priority was establishment of mission safety and security protocols to ensure team and mission well-being. Development and use of a base needs analysis form listing medical conditions and preexisting disabilities as part of the pre-mission assessment facilitated judicious procurement of medical supplies and medications. Implementation of PARM CARES mission clinic intake forms streamlined patient evaluation and post-clinic follow-up; inclusion of a patient consent entry on these forms provided for patient consent to evaluation and treatment. Post-mission debriefings evaluated security, medical supply and medication status, personnel performance, and other aspects of each mission. Essential administrative support provided by PARM-National Headquarters during the November 2013–February 2014 project included mission reporting, documentation, and financial management.
Congenital central hypoventilation syndrome: diagnosis and management
Published in Expert Review of Respiratory Medicine, 2018
Melissa A. Maloney, Sheila S. Kun, Thomas G. Keens, Iris A. Perez
The normal PHOX2B gene contains a repeat sequence of 20 alanines in exon 3. The majority of CCHS patients possess in-frame nucleotide duplications, which leads to expansion of the repeat sequence. Polyalanine repeat tracts are generally stable and unlike the polyglutamine repeats in certain neurodegenerative disorders do not expand when passed from one generation to the next [13,14]. In patients with CCHS, these polyalanine repeat expansion mutations (PARMs) contain 24–33 alanines [15]. Over 90% of CCHS cases are due to a PARM in the PHOX2B gene. The remaining patients possess a non-polyalanine repeat expansion mutation (NPARM) due to missense, nonsense, or frameshift mutations within the PHOX2B gene [16]. Whole and partial PHOX2B gene deletions have been described in individuals with clinical features suggestive of CCHS and may represent another form of disease-causing mutations, but further research is needed to estimate genotype prevalence and understand disease correlations [17]. Widespread implementation of PHOX2B mutation testing has led to the emergence of associations between specific PHOX2B genotypes and CCHS disease features. In general, longer PARM and NPARM genotypes give rise to a more severe CCHS phenotype and individuals with NPARMs tend to exhibit features of syndromic CCHS, with Hirchsprung disease and development of neural crest cell tumors [16,18–20]. A more in-depth review of genotype–phenotype correlations will be discussed later in this review.