Beckwith–Wiedemann Syndrome
Dongyou Liu in Handbook of Tumor Syndromes, 2020
Guidelines have recommended checking serum AFP every 2–3 months until up to 4 years of age [75]. Nevertheless, the downsides of AFP measurement include problematic interpretation in childhood, debated effectiveness, and frequent blood draws potentially resulting in poor adherence to screening. Typically, elevated AFP is observed during the neonatal period, and the level declines continuously until reaching its plateau after age 8 months. Abnormal postnatal elevation in AFP is associated with various tumors, including hepatic tumors and germ cell tumors [97]. In BWS, the AFP concentration is greater and declines significantly more slowly than in healthy children; thus, a normal curve designed specifically for children with BWS should be employed to interpret AFP levels [97]. The level should be repeated within 1 month after an initial elevation; its subsequent lowering level is reassuring, but an increasing level necessitates a search for tumors (either hepatoblastoma or germ cell tumors) with imaging studies. Referral to a pediatric oncologist may be indicated. Studies have shown that abdominal ultrasound may not be sufficient to detect early hepatoblastoma, and that measurement of AFP resulted in lower staging at diagnosis and consequently a greater survival rate [90,98]. Other less invasive methods such as AFP measurement on dried blood spot are being investigated [99].
Genetics and Genetic Testing in Hypertrophic Cardiomyopathy
Srilakshmi M. Adhyapak, V. Rao Parachuri in Hypertrophic Cardiomyopathy, 2020
Genetic testing for HCM in India has become more accessible in the last decade. The costs associated with a genetic panel or a clinical exome have consistently fallen over the years and genetic testing in these patients has now become a practical mode of investigation. The sample of choice for genetic testing is peripheral blood, although other sources of DNA such as buccal swab, dried blood spot, and saliva are viable options.
HIV and Its Complications and Needlestick Injuries
Miriam Orcutt, Clare Shortall, Sarah Walpole, Aula Abbara, Sylvia Garry, Rita Issa, Alimuddin Zumla, Ibrahim Abubakar in Handbook of Refugee Health, 2021
Dried blood spot monitoring for viral load has been used in some humanitarian settings but relies on availability of testing facilities and transport. Point-of-care CD4 count tests can be used alongside clinical status to monitor treatment failure. If neither viral load nor CD4 count testing is available, use indirect methods – that is, self-report, pill count and clinical assessment.
Capillary microsampling in mice: effective way to move from sparse sampling to serial sampling in pharmacokinetics profiling
Published in Xenobiotica, 2020
Amol A. Raje, Vallabh Mahajan, Vishal V. Pathade, Kaushal Joshi, Ashutosh Gavali, Ashwani Gaur, Vishwottam Kandikere
In recent past, significant advances were made in bioanalytical techniques and associated instrumentation to improve the sensitivity of liquid chromatography tandem mass spectrometry (LC-MS/MS) for quantification of lower concentrations with small volume size (Xu et al., 2007). In addition, various bleeding techniques were adopted for enabling collection of multiple PK time points from individual mouse to generate a complete PK profile (Patel et al., 2016). These techniques involved micro-sampling of plasma (Barfield & Wheller, 2011; Bowen et al., 2013; Jonsson et al., 2012b) or blood (usually defined as collection of blood volume less than 50 µL) as dried blood spot (DBS) (Beaudette & Bateman, 2004; Dainty et al., 2012; Dillen et al., 2014; Jonsson et al., 2012a; Kurawattimath et al., 2012; Watanabe et al., 2015; Wickremsinhe et al., 2011). Many research groups have tried serial blood sampling from mice (Bateman et al., 2001; Kurawattimath et al., 2012; Long et al., 2002; Patel et al., 2016; Peng et al., 2009; Rahavendran et al., 2012). Blood samples could be collected from sites like saphenous vein (Hem et al., 1998; Peng et al., 2009), sublingual (Heimann et al., 2009), submandibular/facial vein (Golde et al., 2005), tail vein (Bateman et al., 2001; Kurawattimath et al., 2012; Watanabe et al., 2015) and retro-orbital sinus.
Modern approaches for the phenotyping of cytochrome P450 enzymes in children
Published in Expert Review of Clinical Pharmacology, 2020
Collecting bio-fluids, especially blood and urine, from infants can be a difficult task. Less invasive and more convenient sampling methods exist and may be used in this particular population for CYP450 phenotyping. For instance, saliva has been successfully used in a study performed by El-Yazigi et al. to measure caffeine clearance in order to phenotype CYP1A2 activity in children [10]. In adulthood, the utilization of saliva to phenotype CYP2D6 and CYP3A has also been demonstrated using dextromethorphan and midazolam, respectively [11,12]. However, it requires relatively high doses of probe drugs or a very sensitive analytical method and, to our knowledge, has not yet been tested in pediatrics. The use of dried blood spot (DBS) is also an alternative to conventional blood collection as it requires smaller amounts of blood. DBS is performed by pricking the tip of a finger or even the heel in newborns in order to draw a drop of capillary blood on blotting paper. It may remain however painful in some individuals, particularly in children [5].
Multidrug-resistant tuberculosis in children and adolescents: current strategies for prevention and treatment
Published in Expert Review of Respiratory Medicine, 2021
James A Seddon, Sarah Johnson, Megan Palmer, Marieke M van der Zalm, Elisa Lopez-Varela, Jennifer Hughes, H Simon Schaaf
Efficacy trials for TB medications are rarely done in children, as the anti-mycobacterial effect of a drug in children is assumed to be the same as in adults [46]. Exclusion of children from early TB drug development trials, due to theoretical safety concerns and the desire to ‘protect’ vulnerable patients, has led to restricted access to new drugs in this population and has denied children the associated survival benefit observed in adults. Evaluation of the pharmacokinetics of new drugs is vital in children, to determine the appropriate dose to give by age and weight, and to evaluate for any drug-drug interactions (DDIs). To date, few studies have evaluated the pharmacokinetics of TB drugs in children, and even fewer have evaluated second-line drugs. While challenges exist to conduct these studies, the use of dried blood spot specimen collection, together with sparse sampling and pharmacometric modeling could allow more extensive pharmacokinetic research, even in low-resource settings [47]. Several studies have recently been initiated to determine optimal dosing of novel agents and repurposed drugs, as well as drug-susceptible TB and MDR-TB prevention interventions, specifically for children and adolescents [46].
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