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Biomedical subjects

George A Burghen

Publications and source records attributed to George A Burghen.

6 recordsLinked to original sources
PubMed2005

ACTH deficiency in childhood cancer survivors.

BACKGROUND: Adrenocorticotropin deficiency (ACTHD) can be clinically subtle, but life-threatening if not recognized. We assessed the prevalence of ACTHD in survivors of childhood cancer according to tumor diagnosis/therapy. PROCEDURE: Chart review of endocrine/oncology history was performed in 310 childhood cancer survivors. Patients were referred to endocrine clinic because of slow growth, fatigue, or abnormal pubertal timing. Evaluation of growth hormone (GH), thyrotropin (TSH), ACTH, luteinizing hormone (LH), and follicle-stimulating hormone (FSH) was performed. Low response to metyrapone and/or low dose ACTH test defined ACTHD. RESULTS: ACTHD was identified in 56 (18%), [44 of 182 (24%) central nervous system (CNS) tumors, 3 of 18 (17%) non-CNS cranial tumors, 9 of 97 (9%) hematologic malignancies]. Of the 56 with ACTHD, 53 (95%) had received cranial irradiation (mean 45.5 Gy, range 14-70 Gy); three had not: one each with craniopharyngioma, hypothalamic astrocytoma, and brain stem glioma. All but one also had GH deficiency and/or central hypothyroidism. CONCLUSIONS: Childhood cancer survivors with greatest risk for ACTHD had craniopharyngioma, other suprasellar tumor, or medulloblastoma or > or =24 Gy cranial irradiation. We recommend annual testing for ACTHD for 10-15 years and continued lifelong surveillance after CNS tumor or cranial irradiation, in patients with other hypothalamic-pituitary deficiencies or symptoms of ACTHD.

Adrenocorticotropic Hormone↗
PubMed2005

Single- and multiple-dose pharmacokinetics of pioglitazone in adolescents with type 2 diabetes.

This study assessed the single- and multiple-dose pharmacokinetics of 3 doses (15 mg, 30 mg, and 45 mg) of pioglitazone in 36 adolescents with type 2 diabetes. Blood samples were obtained over a 48-hour interval after the first dose (day 1) and over a 72-hour interval after the last dose (day 15) of pioglitazone and were assayed for pioglitazone and active metabolites (M-III and M-IV). Pioglitazone systemic exposure increased dose dependently but was less than dose proportional during multiple dosing. The median peak pioglitazone concentration occurred at 2 hours. The mean half-life was 8 to 9 hours for pioglitazone and 24 to 32 hours for M-III and M-IV, with similar values at each dose level. During multiple dosing, accumulation for pioglitazone was negligible, but it reached 2.5- to 3.0-fold for M-III and M-IV. The sustained total serum concentration of active compounds during multiple dosing provides the basis for once-daily dose administration of pioglitazone in adolescents.

Adolescent↗
PubMed2004

Hypothalamic dysfunction after chemotherapy.

Cranial irradiation with or without chemotherapy can cause hypothalamic-pituitary dysfunction. Chemotherapy without cranial irradiation has not been thought to cause such deficiency. In order to determine whether chemotherapy without cranial irradiation can lead to hormonal deficiency, we reviewed the medical records of 362 childhood cancer patients who underwent full hypothalamic-pituitary evaluation because of altered growth and development after oncological therapy (1987-2002). Of these, 31 received chemotherapy but no cranial or total body irradiation and had no CNS tumor: 18 had hematological malignancy and 13 had a solid tumor of the torso or extremity. Duration of follow-up was 13.0 +/- 4.1 years (mean +/- SD). Growth hormone deficiency (GHD) was identified in 15 (48%), central hypothyroidism (TSH-D) in 16 (52%), and pubertal abnormalities in 10 (32%). Pubertal abnormalities included precocious puberty in two (6%), gonadal failure in five of 27 who were old enough to assess puberty (19%), and gonadotropin deficiency in three of 27 (11%). GHD and TSH-D were co-existent in eight patients (26%). Overall, 81% (n = 25) had GHD, TSH-D, precocious puberty, and/or gonadotropin deficiency. None had ACTH or ADH deficiency or primary hypothyroidism. Of note, this was not a study of prevalence, but rather an evaluation of clinically referred patients. In conclusion, hypothalamic dysfunction may occur in survivors of non-CNS tumors who receive chemotherapy but do not receive cranial irradiation. We recommend at least annual observation of growth rate and pubertal development of all children treated for pediatric malignancies, with evaluation for GHD, TSH-D, pubertal abnormalities, and other hypothalamic dysfunction in all poorly-growing cancer survivors, even those not treated with cranial irradiation.

Adolescent↗
PubMed2003

Risk factors for the development of obesity in children surviving brain tumors.

Hypothalamic obesity, a syndrome of intractable weight gain due to hypothalamic damage, is an uncommon but devastating complication for children surviving brain tumors. We undertook a retrospective evaluation of the body mass index (BMI) curves for the St. Jude Children's Research Hospital brain tumor population diagnosed between 1965 and 1995 after completion of therapy to determine risk factors for the development of obesity. Inclusion criteria were: diagnosis less than 14 yr of age, no spinal cord involvement, ambulatory, no supraphysiologic hydrocortisone therapy (>12 mg/m(2) x d), treatment and follow-up at St. Jude Children's Research Hospital, and disease-free survival greater than 5 yr (n = 148). Risk factors examined were age at diagnosis, tumor location, histology, extent of surgery, hydrocephalus requiring ventriculoperitoneal shunting, initial high-dose glucocorticoids, cranial radiation therapy, radiation dosimetry to the hypothalamus, intrathecal chemotherapy, and presence of endocrinopathy. Analyses were performed both between groups within a risk factor and against BMI changes for age in normal children older than 5.5 yr (the age of adiposity rebound). Risk factors were: age at diagnosis (P = 0.04), radiation dosimetry to the hypothalamus (51-72 Gy, P = 0.002 even after hypothalamic and thalamic tumor exclusion), and presence of any endocrinopathy (P = 0.03). In addition, risk factors when compared with BMI slope for the general American pediatric population included: tumor location (hypothalamic, P = 0.001), tumor histology (craniopharyngioma, P = 0.009; pilocytic astrocytoma, P = 0.043; medulloblastoma, P = 0.039); and extent of surgery (biopsy, P = 0.03; subtotal resection, P = 0.018). These results verify hypothalamic damage, either due to tumor, surgery, or radiation, as the primary cause of obesity in survivors of childhood brain tumors. In particular, hypothalamic radiation doses of more than 51 Gy are permissive. These results reiterate the importance of the hypothalamus in energy balance, provide risk assessment criteria for preventative measures before the development of obesity in at-risk patients, and suggest therapeutic strategies to reduce the future development of obesity.

Astrocytoma↗
PubMed2002

Preirradiation endocrinopathies in pediatric brain tumor patients determined by dynamic tests of endocrine function.

PURPOSE: To prospectively evaluate pediatric patients with localized primary brain tumors for evidence of endocrinopathy before radiotherapy (RT). METHODS AND MATERIALS: Seventy-five pediatric patients were evaluated with the arginine tolerance test and L-dopa test for growth hormone secretory capacity and activity; thyroid-stimulating hormone surge and thyrotropin-releasing hormone stimulation test for the hypothalamic-thyroid axis; the 1-microg adrenocorticotropin hormone (ACTH) and metyrapone test for ACTH reserve; and, depending on age, a gonadotropin-releasing hormone stimulation test to determine gonadotropin response. The study included 38 male and 37 female patients, age 1-21 years with ependymoma (n = 35), World Health Organization (WHO) Grade I-II astrocytoma (n = 18), WHO Grade III-IV astrocytoma (n = 10), craniopharyngioma (n = 7), optic pathway tumor (n = 4), and germinoma (n = 1). Seven patients receiving dexamethasone at the time of the evaluation were excluded from the final analysis. RESULTS: Of 68 assessable patient, 45 (66%) had evidence of endocrinopathy before RT, including 15 of 32 patients (47%) with posterior fossa tumors. Of the 45 patients, 38% had growth hormone deficiency, 43% had thyroid-stimulating hormone secretion abnormality, 22% had an abnormality in ACTH reserve, and 13% had an abnormality in age-dependent gonadotropin secretion. CONCLUSION: The incidence of pre-RT endocrinopathy in pediatric brain tumor patients is high, including patients with tumors not adjacent to the hypothalamic-pituitary unit. These data suggest an overestimation in the incidence of radiation-induced endocrinopathy. Baseline endocrine function should be determined for brain tumor patients before therapy. The potential for radiation-induced endocrinopathy alone cannot be used as an argument for alternatives to RT for most patients. Pre-RT endocrinopathy may be an early indicator of central nervous system damage that will influence the functional outcome unrelated to RT.

Adolescent↗