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Biomedical subjects

D B Allen

Publications and source records attributed to D B Allen.

At least 19 recordsLinked to original sources
PubMed2002

Safety of fluticasone propionate cream 0.05% for the treatment of severe and extensive atopic dermatitis in children as young as 3 months.

BACKGROUND: Topical corticosteroids are useful for the treatment of pediatric dermatoses. However, concerns regarding possible systemic and topical toxicities have limited the use of moderate-potency corticosteroids in children. OBJECTIVE: Our purpose was to characterize the safety of fluticasone propionate cream in children. METHODS: Children between 3 months and 5 years 11 months (n = 32) and 3 up to 6 years of age (n = 19) with moderate to severe atopic dermatitis (> or =35% body surface area; mean body surface area treated, 64%) were treated with fluticasone propionate cream, 0.05% twice daily for 3 to 4 weeks. Serum cortisol response, fluticasone levels, skin changes, and adverse events were analyzed. RESULTS: Mean cortisol levels were similar at baseline (13.76 +/- 6.94 microg/dL prestimulation and 30.53 +/- 7.23 microg/dL poststimulation) and at end of treatment (12.32 +/- 6.92 microg/dL prestimulation and 28.84 +/- 7.16 microg/dL poststimulation). Only 2 of 43 children had end-treatment poststimulation values less than 18.0 microg/dL. No significant adverse cutaneous effects were noted. CONCLUSION: Fluticasone propionate cream 0.05% appears to be safe for the treatment of severe eczema for up to 4 weeks in children 3 months of age and older.

Administration, Topical↗
PubMed2001

Prader-Willi syndrome: how does growth hormone affect body composition and physical function?

Children with Prader-Willi syndrome (PWS) display diminished growth, reduced muscle mass (lean body mass), and increased adipose tissue-body composition abnormalities resembling those seen in growth hormone (GH) deficiency. Diminished GH responses to various provocative agents, low insulin-like growth factor-I levels, and the presence of other hypothalamic dysfunction support the presence of true GH deficiency (GHD) in many children with PWS. GH treatment in these children decreases body fat, and increases linear growth, muscle mass, fat utilization and energy expenditure. Strength and agility are also improved. These improvements are most dramatic during the first year of GH therapy, and prolonged treatment still does not 'normalize' these parameters. The metabolic effects, including changes in physical strength and agility, may be the most important features for this particular pediatric population. These observations support a contribution of GHD to disabilities of children with PWS, and a clinically significant benefit of GH treatment.

Body Composition↗
PubMed2000

Risk of persistent growth impairment after alternate-day prednisone treatment in children with cystic fibrosis.

BACKGROUND: It is uncertain whether the growth impairment that occurs in children during long-term treatment with glucocorticoids persists after the medication is discontinued and ultimately affects adult height. METHODS: We evaluated growth six to seven years after alternate-day treatment with prednisone had been discontinued in 224 children 6 to 14 years of age with cystic fibrosis who had participated in a multicenter trial of this therapy from 1986 through 1991. Of the children, 151 had been randomly assigned to receive prednisone (either 1 or 2 mg per kilogram of body weight) and 73 to receive placebo. We obtained data on growth up to 1997 from the Cystic Fibrosis Foundation Patient Registry and standardized the data to sex- and age-specific norms from the National Center for Health Statistics. We used z scores to compare growth patterns among treatment groups. RESULTS: In 1997, 68 percent of the patients were 18 years of age or older. The z scores for height declined during prednisone therapy; catch-up growth began two years after treatment with prednisone was discontinued. Among the boys, the z scores for height in those treated with prednisone remained lower than the scores for those who received placebo (P=0.02). The mean heights for boys 18 years of age or older were 4 cm less in the prednisone groups than in the placebo group, an equivalent of 13 percentile points (P=0.03). Among the girls, differences in height between those who were treated with prednisone and those who received placebo were no longer present two to three years after prednisone therapy was discontinued. CONCLUSIONS: Among children with cystic fibrosis who have received alternate-day treatment with prednisone, boys, but not girls, have persistent growth impairment after treatment is discontinued.

Adolescent↗
PubMed2000

Do intranasal corticosteroids affect childhood growth?

Topical intranasal corticosteroids (INS) are the most effective treatment for allergic rhinitis and are being increasingly prescribed to children. Due to the potent inhibition of childhood growth seen with oral corticosteroids, it is important to examine whether INS could have similar effects. The evidence available suggests that some INS, such as beclomethasone dipropionate (BDP), may slow growth when used regularly for prolonged periods. However, newer INS such as fluticasone propionate (FP) and mometasone furoate, which have substantially reduced bioavailability via gastrointestinal absorption, are unlikely to do so. Well-designed prospective studies are needed to distinguish those INS with reduced or absent effects on growth. In practice, choosing an INS which optimises the ratio of therapeutic effect to systemic bioavailability will probably reduce the risk of growth suppression to a negligible level.

Androstadienes↗
PubMed2000

Systemic effects of intranasal steroids: an endocrinologist's perspective.

Intranasal steroids (INSs) are established as first-line treatment for allergic rhinitis. Extensive use of INSs with few reported adverse events supports the safety of these medications. Nevertheless, the prescription of more potent INSs for consistent and more prolonged use to younger and older patients, often in combination with inhaled corticosteroids, justifies the careful examination of their potential adverse systemic effects. Systemic bioavailability of INSs, by way of nasal and intestinal absorption, can be substantial; but current INSs vary significantly in their degree of first-pass hepatic inactivation and clearance from the body of the swallowed drug. For safety studies of INSs, distinguishing detectable physiologic perturbations from important adverse events is aided by an understanding of normal endocrine physiology and the methods used to test these systems. A review of available information indicates that (1) sensitive tests can measure the effects of INSs on biologic feedback systems, but they do not accurately predict clinically relevant adverse effects; (2) the primary factors that influence the relationship between therapeutic and adverse systemic effects of INSs are dosing frequency and efficiency of hepatic inactivation of swallowed drug; (3) INS treatment in recommended doses does not cause clinically significant hypothalamic-pituitary-adrenal axis suppression; (4) growth suppression can occur with twice-daily administration of certain INSs but does not appear to occur with once-daily dosing or with agents with more complete first-pass hepatic inactivation; (5) harmful effects of INSs on bone metabolism have not yet been adequately studied but would not be expected with the use of an INS dose and dosing frequency that do not suppress basal hypothalamic-pituitary-adrenal axis function or growth; and (6) these conclusions apply to INS treatment alone and in recommended doses-the risk of adverse effects in individual patients who are treated with INSs is increased by excessive dosing or concomitant inhaled corticosteroid or other topical corticosteroid therapy.

Administration, Intranasal↗
PubMed2000

Sustained benefit after 2 years of growth hormone on body composition, fat utilization, physical strength and agility, and growth in Prader-Willi syndrome.

BACKGROUND: Obesity and hypotonia in children with Prader-Willi syndrome (PWS) are accompanied by abnormal body composition resembling a growth hormone (GH)-deficient state. Hypothalamic dysfunction in PWS includes decreased GH secretion, suggesting a possible therapeutic role for GH treatment. Although recent studies have demonstrated short-term benefits of treatment with GH, a critical question is whether beneficial changes persist or wane with prolonged therapy. OBJECTIVES AND METHODS: Effects of 24 months of GH treatment (1 mg/m(2)/d) on growth, body composition, strength and agility, pulmonary function, resting energy expenditure, and fat utilization were assessed in 35 children with PWS. Percent body fat, lean muscle mass, and bone mineral density were measured by dual-energy x-ray absorptiometry. Indirect calorimetry was used to determine resting energy expenditure and to calculate the respiratory quotient. RESULTS: Compared with baseline evaluations, increased height velocity (SD score -1.1 +/- 2.5 to 2.2 +/- 2.3; P <. 001), reduced percent body fat (46.4% +/- 8.4% to 40.3% +/- 10.0%, P <.001), and improved respiratory muscle function and physical strength and agility (sit-ups, weight-lifts, running speed, and broad jump; P <.01) were observed after 24 months of GH treatment. A decline in respiratory quotient (0.81 +/- 0.07 to 0.75 +/- 0.06; P <. 01) and a trend toward increased resting energy expenditure were also observed. Changes in response to GH occurred predominantly during the initial 12 months of GH therapy. CONCLUSIONS: Children with PWS had sustained increases in lean body mass, decreases in percent body fat, improvements in physical strength and agility, and increased fat oxidation after 24 months of GH therapy. However, between 12 and 24 months, the growth rate slowed. Consequently, encouraging initial results require even more prolonged study to draw conclusions regarding the long-term value of GH therapy in changing body composition in children with PWS.

Adipose Tissue↗
PubMed2000

Effects of growth hormone on body composition and bone metabolism.

Physiologic effects of growth hormone (GH) extend beyond the stimulation of linear growth during childhood and adolescence. These effects include building and sustaining lean body mass, facilitating the utilization of fat mass for energy needs, and maintaining bone mineral density. These nongrowth effects of GH appear to be important throughout life. Children and adults with severe GHD demonstrate marked reductions in lean body mass, increases in percent body fat, and subnormal bone mineral density. Replacement of GH attenuates these abnormalities, though it remains unknown whether it does so completely. Children with body composition abnormalities resembling the GHD state (e.g., Prader-Willi syndrome) also appear to respond favorably to administration of GH treatment, and demonstrate concomitant improvements in strength and agility. Long-term body composition benefits of GH supplementation in these and other non-GHD individuals remain unproven.

Adolescent↗
PubMed2000

Effects of growth hormone on adipose tissue.

Physiological effects of growth hormone (GH) extend beyond the stimulation of linear growth. These include important metabolic effects upon adipose tissue. GH affects both proliferation and differentiation of preadipocytes, although this varies between clonal cell lines and preadipocyte cultures. Both preadipocytes and mature adipocytes possess specific GH receptors. GH may mediate its actions via these receptors, but some effects are indirectly mediated through the GH-mediated secretion of insulin-like growth factor-I (IGF-I) within adipose tissue. GH promotes lipolysis via inhibition of lipoprotein lipase, which hydrolyzes triglycerides in the circulation to make them available for triglyceride accumulation in adipose tissue. GH also stimulates hormone sensitive lipase (HSL), the rate-limiting step for release of stored triglyceride in adipocytes (lipolysis). As GH becomes utilized for various "non-growth" concerns (see Figure 1), awareness of the metabolic effects on adipocytes is important to understand the clinical effects seen with GH therapy.

Adipose Tissue↗
PubMed2000

Growth hormone use in pediatric growth hormone deficiency and other pediatric growth disorders.

The diagnosis and management of growth disorders in children, particularly disorders that respond to therapy with growth hormone (GH), raise challenging clinical and economic issues. Several such issues are presented in the following article in which Dr. Ron Rosenfeld examines the evaluation and diagnosis of the child with short stature; Dr. David B. Allen discusses the anabolic and metabolic indications for GH treatment in children; Dr. Margaret H. MacGillivray reviews GH dosing, height outcomes, and follow up; and Dr. Craig Alter presents the payer's perspective on the diagnosis and treatment of pediatric GH deficiency. In addressing the use of GH in other pediatric populations, Dr. Paul Saenger focuses on Turner syndrome, Dr. Henry Anhalt on chronic renal insufficiency of childhood, and Dr. Ray Hintz on idiopathic short stature. Dr. Harvey P. Katz presents one managed care organization's policy and implementation plan that is used to guide decisions regarding coverage for GH treatment.

Body Height↗
PubMed1999

Growth hormone improves body composition, fat utilization, physical strength and agility, and growth in Prader-Willi syndrome: A controlled study.

BACKGROUND: Obesity and hypotonia in children with Prader-Willi syndrome (PWS) are accompanied by abnormal body composition and diminished energy expenditure resembling a growth hormone deficient state. Hypothalamic dysfunction in PWS often includes decreased growth hormone (GH) secretion, suggesting a possible therapeutic role for exogenous GH treatment. OBJECTIVES AND METHODS: After 6 months of observation to determine baseline growth rate, and with the use of a 12-month randomized controlled study design, the effects of GH treatment (1 mg/m2/d) on growth, body composition, strength and agility, pulmonary function, resting energy expenditure (REE), and fat utilization were assessed in 54 children with PWS (n = 35 treatment and n = 19 control). Percent body fat and bone mineral density were measured by dual x-ray absorptiometry. Indirect calorimetry was used to determine REE and to calculate respiratory quotients. RESULTS: Stimulated levels of GH in response to clonidine testing were low in all patients (peak, 2.0 ng/mL). After 12 months, GH-treated subjects showed significantly increased height velocity Z scores (mean, 1.0 1.7 to 4.6 2.9; P <.001), decreased percent body fat (mean, 46.3% 8.4% to 38.3% 10.7%; P <.001), and improved respiratory muscle function, physical strength, and agility (sit-ups, weight-lifts, running speed, and coordination). A significant decline in respiratory quotients occurred during GH therapy (0.81 to 0.77, P <.001), but total REE did not change. CONCLUSIONS: GH treatment of children with PWS accelerated growth, decreased percent body fat, and increased fat oxidation but did not significantly increase total REE. Improvements in respiratory muscle strength, physical strength, and agility also occurred, suggesting that GH treatment may have value in reducing some physical disabilities experienced by children with PWS.

Adipose Tissue↗
PubMed1999

Assessment of SNRPN expression as a molecular tool in the diagnosis of Prader-Willi syndrome.

BACKGROUND: Prader-Willi syndrome (PWS) is associated with lesions of the paternal chromosome 15q11- 13. Recently, loss of expression of a paternally expressed gene in this region, SNRPN, has been proposed as a molecular hallmark of PWS. The goal of this study was to determine the diagnostic accuracy of SNRPN expression in a well-characterized cohort of PWS patients. METHODS: SNRPN expression was analyzed by reverse transcription coupled to polymerase chain reaction (RT-PCR). RNA was isolated from peripheral blood leukocytes and subjected to multiplex RT-PCR in which expression of SNRPN and a constituitively expressed internal control gene were analyzed. The amplified products were electrophoresed in agarose gels and visualized by ethidium bromide staining. RESULTS: Multiplex RT-PCR was applied to RNAs isolated from 30 normal control subjects and 30 well- characterized PWS patients. All control patients expressed the SNRPN and internal control genes. In contrast, all 30 PWS patients demonstrated loss of SNRPN expression, with integrity of RNA being demonstrated by the presence of internal control gene expression. CONCLUSIONS: Loss of SNRPN expression appears to be a consistent finding in PWS. Expression analysis of SNRPN offers a novel approach for the diagnostic evaluation of PWS that is robust and can be performed in a single day.

Adolescent↗
PubMed1999

Limitations of short-term studies in predicting long-term adverse effects of inhaled corticosteroids.

This paper examines the value of short-term studies in predicting long-term, clinically relevant adverse effects of inhaled corticosteroids (ICS) in children with asthma. Increasing use of ICS in younger and less severely affected children with asthma justifies concern about long-term adverse effects. For each system potentially affected by ICS, short-term and sensitive studies have limited value in predicting clinically relevant effects, even when correlations are highly statistically significant. This is due to inherent limitations of the short-term tests utilized and normal physiologic variations in systems being studied. Specific limitations include: 1) poor distinction between systemic presence of ICS and adverse systemic effects (e.g., integrated plasma cortisol) 2) lack of data validating the connection between test results and the end point in question (bone markers to predict growth and fracture risk) 3) sensitivity confounded by normal physiologic variation (knemometry to predict long-term growth). Consequently, predicting clinically relevant long-term effects from short-term studies detecting physiologic perturbations remains a challenge. Positive predictive value is improved by well-designed intermediate-term (>12 months) studies utilizing dynamic hypothalamic-pituitary-adrenal (HPA) axis testing, dual x-ray absorptiometry (DXA) scanning, or precise stadiometry. Ultimately, however, long-term studies are required to assess long-term risks, and the reliability of short-term assessments in predicting them.

Administration, Inhalation↗
PubMed1999

Physical effects of growth hormone treatment in children with Prader-Willi syndrome.

A randomized, controlled study of 54 children (age, 4-16 years) with Prader-Willi syndrome was conducted to assess the potential beneficial effects of growth hormone (GH) treatment. After observation for 6 months, the children were randomized to receive GH at a dose of 3 IU/m2/day (1 mg/m2/day) (n = 35) or no intervention (n = 19). The effects of GH treatment on linear growth, body composition, muscle strength, pulmonary function and resting energy expenditure were assessed. The levels of GH secreted in response to clonidine stimulation were universally low, and mean (+/- SD) insulin-like growth factor I SDS was -1.2 +/- 0.8 pretreatment. In children treated for 1 year, mean height velocity SDS significantly increased from -1.0 +/- 2.5 to 4.6 +/- 2.9 (p < 0.0001), mean percentage body fat decreased from 46.3 +/- 8.4% to 38.4 +/- 10.7% (p < 0.001), mean lean body mass increased from 20.5 +/- 6.3 kg to 25.6 +/- 4.3 kg (p < 0.01) and respiratory muscle function and physical strength improved. Mean respiratory quotients significantly decreased from 0.81 to 0.77 (p < 0.001); however, resting energy expenditure did not change. Therefore, GH therapy appears to reduce some of the physical disabilities experienced by children with Prader-Willi syndrome.

Adolescent↗
PubMed1999

Persistent infantile hypothyroidism attributable to thyroxine-binding globulin deficiency.

An infant diagnosed with thyroid-binding globulin (TBG) deficiency after newborn screening demonstrated persistent elevation of thyroid-stimulating hormone (TSH) and abnormally low free thyroxine (fT4) levels. Treatment with thyroxine (T4) normalized fT4 and TSH levels during the first 5 years of life, but withdrawal of T4 supplementation at that time was associated with return of hyperthyrotropinemic hypothyroidism. To our knowledge, this patient is the first reported case of TBG deficiency-associated hypothyroidism. In rare instances, TBG deficiency may lead to hypothyroidism requiring hormone supplementation.

Humans↗
PubMed1999

Issues in the transition from childhood to adult growth hormone therapy.

The consequences of severe growth hormone deficiency (GHD) in adults and the beneficial effects of GH replacement therapy are clear. However, the majority of children who have a diagnosis of GHD and who are treated with GH do not have permanent GHD and will not require treatment during adulthood. Several issues must be considered in selecting candidates for adult GH treatment and transitioning their care from pediatrics to adult medicine. Counseling about possible lifelong treatment should focus on children with panhypopituitarism and those with severe isolated GHD that is associated with central nervous system abnormalities. When to terminate growth-promoting GH therapy should be guided by balancing the high cost of late-adolescent treatment with the attainment of reasonable statural goals. Retesting for GH secretion is appropriate for all candidates for adult GH therapy; the GH axis can be tested within weeks after the cessation of treatment, but confirming an emerging adult GHD state with body composition, blood lipid, and quality-of-life assessments may require 1 year or more of observation. Selecting patients for lifelong adult GH replacement therapy will present diagnostic, therapeutic, and ethical problems similar to those in treating childhood GHD. The experience and expertise of pediatric endocrinologists in diagnosing and treating GHD should be offered and used in identifying and transitioning appropriate patients to adult GH therapy.

Adult↗