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Biomedical subjects

P R Blackett

Publications and source records attributed to P R Blackett.

At least 19 recordsLinked to original sources
PubMed2000

Body mass index (BMI) in Turner Syndrome before and during growth hormone (GH) therapy.

OBJECTIVE: To study whether body mass index (BMI) is different in girls with Turner syndrome (TS) compared to normal girls, and whether BMI in TS is affected by growth hormone (GH) treatment. DESIGN: A retrospective cross-sectional study. SUBJECTS: 2468 girls with TS enrolled in the National Cooperative Group Study (NCGS), a collaborative surveillance study for assessing GH-treated children. MEASUREMENTS: BMI and BMI standard deviation score (BMI SDS) at baseline and during GH treatment were computed from height and weight data. RESULTS: BMI in TS patients increases with age as expected. However, BMI SDS increased starting at about age 9 y. A similar pattern of increase in BMI SDS was observed after each year of GH treatment for up to 4 y, but GH treatment did not change the magnitude of increase. BMI and BMI SDS curves before and during GH treatment were essentially superimposable. CONCLUSION: These findings suggest that mechanisms specific for TS are responsible for the age-related increase in BMI SDS. This increase was unaffected by GH treatment.

Adolescent↗
PubMed1999

Effect of newborn screening for congenital adrenal hyperplasia.

OBJECTIVE: To compare the incidence of diagnosis and morbidity in newborns who were screened with newborns who were not screened for congenital adrenal hyperplasia (CAH). DESIGN: A retrospective cohort study. SETTING: Arkansas, Oklahoma, and Texas. PATIENTS: An unscreened population in Arkansas and Oklahoma (n = 400118) was compared with a screened population in Texas (n = 1613378) during a 5-year period. Simultaneous data were collected on the incidence of diagnosis and associated morbidity in patients with CAH. MAIN OUTCOME MEASURES: Diagnosis of CAH, age (in days) at diagnosis, and frequency and length of initial hospitalization. RESULTS: The incidence of diagnosis of classic CAH per 100000 newborns in the unscreened cohort (5.75) and in the screened cohort (6.26) was similar (relative risk, 0.92; 95% confidence interval, 0.58-1.44). The unscreened group had 0.73 fewer male newborns with salt-wasting CAH diagnosed per 100000 newborns (relative risk, 0.73; 95% confidence interval, 0.35-1.56). The median age at diagnosis was 26 days for male newborns with salt-wasting CAH in the unscreened cohort vs 12 days in the screened cohort (z = 2.49; P = .01). Male newborns with simple-virilizing CAH and newborns with nonclassic CAH were detected only in the screened cohort. CONCLUSIONS: There was not a statistically significant (P = .73) increase in the diagnosis of salt-wasting CAH in the screened cohort. Male newborns benefited as a result of significantly (P = .01) earlier diagnosis, reduced morbidity, and shorter lengths of hospitalization. Large collaborative studies or meta-analyses are needed to determine the life-saving benefits of screening.

17-alpha-Hydroxyprogesterone↗
PubMed1996

Lipoprotein changes in relation to body mass index in Native American adolescents.

In view of their known high incidence of noninsulin dependent diabetes (NIDDM), we sought to determine whether Native American (Plains Indian) children and adolescents show evidence of risk factors for both NIDDM and cardiovascular disease. Children and adolescents between the ages of 4 and 19 y were recruited, and field days were organized for data collection, which included height, weight [to compute body mass index (BMI)], waist and hip circumference, family histories, quantum of Native American ancestry, and blood sampling for fasting lipids, apolipoproteins, insulin, and glucose. BMI increased with age in boys and girls and tended to be higher than in Caucasian children. The difference was significant in 5-9-y-old (p < 0.05) and 10-14-y-old (p < 0.05) boys and 10-14-y-old girls (p < 0.001). Ten- to 14-y-old girls in the highest quartile for BMI had higher triglyceride levels (p < 0.05) and lower HDL cholesterol (p < 0.001) when compared with those in the lower quartiles. In contrast, 15-19 y olds in the highest quartile for BMI had higher cholesterol, LDL cholesterol, and apolipoprotein B (p < 0.001). The mean fasting insulin levels were not related to BMI. The data suggest that, within this Plains Indian population, obesity associated with elevated lipid levels tends to begin at an early age in Native American children. Insulin levels do not appear to be related to BMI, a putative index of adiposity, in this population of children known to be prone to NIDDM in adult life.

Adolescent↗
PubMed1995

FH Tulsa-1 and -2: two unique alleles for familial hypercholesterolemia presenting in an affected two-year-old African-American male.

A two-year-old African American boy presented with cutaneous xanthomata and extreme hypercholesterolemia. Subsequent studies revealed that the LDL-cholesterol was 1,001 mg/dl and apoB 507 mg/dl. LDL-receptor activity was almost undetectable, which is compatible with the finding of two newly described defective alleles on exon 4 of the LDL-receptor gene coding for part of the ligand-binding domain. One allele contained a 21 base-pair insertion from codon 200 to 207 whereas the other had a point mutation at codon 207. The rarity of genes for FH reported in individuals of African ancestry is discussed.

Alleles↗
PubMed1994

Lipids and apolipoproteins in growth hormone-deficient children during treatment.

The role of growth hormone (GH) in regulating the transport of plasma lipoproteins has not been clearly defined, but past studies suggest that GH may influence cholesterol levels. This protocol was designed to evaluate possible changes in lipid and apolipoprotein status in GH-deficient children and children with neurosecretory dysfunction (NS) before GH therapy and at intervals after GH therapy was started. Twenty children with classic GH deficiency were evaluated, and 28% were hyperlipidemic at the onset of the study. Seven children were evaluated in the NS group, and only one (14%) showed an elevated total cholesterol (TC) greater than 200 mg/dL. The mean TC for all the GH-deficient children was elevated above the normal range, but not for the NS group. The mean apolipoprotein (apo) C-III level and its heparin-precipitated fraction (HP) were also elevated in the GH-deficient group, but only the apo C-III HP was elevated in the NS group. A standard replacement dose of recombinant methionyl GH was used, and therapy had no significant effect on TC or triglyceride (TG) levels. Apo C-III HP, a marker of hypertriglyceridemia, increased after the start of therapy, but no other lipoprotein levels changed significantly in the GH-deficient group. No changes were seen with treatment in the NS group. The longitudinal design of this study allowed demonstration of the later changes in the apolipoproteins and the presence of a distinct subset of patients with both GH deficiency and hypercholesterolemia. This study supports the role of GH in modulating lipid metabolism.

Adolescent↗
PubMed1993

Hyperlipidemia in children.

Advances toward improving cardiovascular health of tomorrow's adults lie both in acknowledging that the pathogenesis of atherosclerosis begins in childhood and in considering the influence of environmental factors on genetic endowment of risk. Based on current understanding of lipoprotein transport processes, an array of genetic disorders with various degrees of atherogenicity can be classified according to the predominant lipoprotein density class, as represented by a standard lipid profile, and then further defined by assaying apolipoproteins and their receptors, lipoprotein transport enzymes, or the respective variant genes. Alternatively, a simple and potentially cost-effective representation of multifactorial influences on lipid transport is provided by an assessment of apolipoprotein particle composition using serial immunologic precipitation of apolipoproteins while on their intact plasma lipoproteins. A comprehensive intervention strategy can be based on identification of inherited risk and the effects of nongenetic factors, which include dietary excess, inactivity, disease states, and medications.

Adolescent↗
PubMed1990

Diabetic ketoacidosis at the Children's Hospital of Oklahoma: a review on presentation and management.

Examination of 394 cases of diabetic ketoacidosis presenting at the Children's Hospital of Oklahoma from 1975 to 1987 has indicated a higher frequency of very young patients with low insulin requirements and frequent presentation in the winter months. The severity of the preceding hyperglycemia varies widely as indicated by the range of glycosylated hemoglobin values at the time of diagnosis. In addition we have identified measures to prevent the main hazards occurring during therapy which are related to potassium replacement and correction of dehydration without causing cerebral edema. The general principles of management are reviewed and we have selected certain aspects for emphasis and discussion based on past experience.

Child↗
PubMed1989

Dominantly inherited childhood gigantism resembling Sotos' syndrome.

Excessive growth in infancy and onset of puberty at age four was observed in a boy with features resembling Sotos syndrome. Early development of secondary sexual characteristics and advanced osseous maturation were observed. The family history was significant; excessive weight gain tended to occur in female family members in association with rapid growth in infancy and childhood. A delayed insulin response to glucose was observed in both mother and sister, and diabetes developed during his mother's gestation. These observations suggest that undetermined factors associated with excessive growth may be inherited as a dominant trait with variable expression.

Child↗
PubMed1986

Plasma lipids and apolipoproteins in a 13-year-old boy with diabetic ketoacidosis and extreme hyperlipidemia.

A 13-year-old boy with untreated diabetes presented in severe ketoacidosis (DKA) for the first time with an initial triglyceride (TG) level of 14,461 mg/dl. Serial blood samples were drawn to determine the interrelationships of changes in lipids and apolipoproteins during treatment with insulin and intravenous fluids. The TG level declined to 122 mg/dl in 7 days concomitant with a lowering of apolipoproteins C-II, C-III, E, D, and F. Further observations suggested that the TG-rich lipoproteins underwent degradation associated with a decline in the levels of apolipoproteins associated with very low density lipoprotein (VLDL) in contrast to an increase in high density lipoprotein-cholesterol (HDL-C), ApoA-I and ApoA-II. ApoB and low density lipoprotein cholesterol (LDL-C) were increased transiently. Subsequent therapy with continuous subcutaneous insulin infusion (CSII) were effective in maintaining glucose homeostasis and normolipidemia for 6 months.

Adolescent↗
PubMed1985

Increased levels of HDL-cholesterol and apolipoprotein A-I after intensified insulin therapy for diabetes.

Sixteen subjects with insulin-dependent diabetes mellitus were studied to determine whether changes in plasma lipids and apolipoproteins follow intensified control using preprandial doses of regular insulin with an additional dose of NPH insulin before bedtime. The mean total dialy dose of insulin was increased from 1.03 +/- 0.09 to 1.17 +/- 0.44 units/kg throughout the six-month period. Levels of HDL-cholesterol and apolipoprotein A-I increased without significant changes in hemoglobin A1 (HbA1), triglyceride, or cholesterol. These findings suggest that increases in HDL-cholesterol and apolipoprotein A-I were a result of the intensified insulin delivery.

Adolescent↗
PubMed1984

Studies of lipids, lipoproteins, and apolipoproteins in Menkes' disease.

Three patients with Menkes' disease, an inherited disorder of copper transport, were studied to determine whether the copper deficiency was associated with a lipoprotein disorder. Hypocuprinemia was documented in all three cases. Two patients had severe copper and ceruloplasmin deficiencies, whereas the third patient had a less severe deficiency. Hypertriglyceridemia was observed in the first patient, and elevations in triglyceride, cholesterol, apolipoprotein B (ApoB), and apolipoprotein C-III (ApoC-III) occurred predominantly in the very low density lipoprotein fraction (VLDL). This patient had normal lipoprotein lipase activity but mild glucose intolerance. The second patient had a borderline high cholesterol level with normal plasma triglycerides and apolipoproteins, whereas the third patient appeared to have normal total cholesterol but slightly higher triglycerides with elevated plasma apolipoprotein E (ApoE). No striking differences were observed in the chemical composition of all lipoprotein subfractions between patients and controls except that the neutral lipid content of VLDL was higher in patients than in controls. The ApoB was initially normal in molecular weight but degraded faster than the controls during storage. The appearance of the major low density lipoprotein (LDL) fraction of the first two patients was opaque white, in contrast to clear yellow in the third patient and in the age- and diet-matched controls. This abnormal appearance of LDL in these patients was associated with low plasma levels of beta-carotene and ceruloplasmin. These findings suggest that decreased serum copper levels may be associated with lipid and lipoprotein abnormalities and may enhance lipid peroxidation of LDL accounting for the color change.(ABSTRACT TRUNCATED AT 250 WORDS)

Apolipoprotein C-III↗
PubMed1983

Desmopressin response of enuretic children. Effects of age and frequency of enuresis.

To characterize the children with enuresis likely to respond to desmopressin acetate, we performed a double-blind crossover study that included the use of a placebo. During the two weeks of desmopressin administration, six children (12%) had 13 or 14 dry nights, and 15 children (29%) had eight to 12 dry nights. Among the 17 children aged 9 years or older, with four to seven dry nights during the two-week baseline period, 12 children (71%) responded to desmopressin (eight to 14 dry nights). In contrast, none of the 15 children younger than 9 years of age with fewer than three dry nights before therapy responded. During the posttreatment period, only four of the 21 drug responders reported a persistent effect. Desmopressin may be effective in reducing the frequency of enuresis, especially in children older than 9 years of age without nightly enuresis.

Adolescent↗
PubMed1982

Growth hormone in the regulation of hyperlipidemia.

Plasma concentrations of triglyceride, cholesterol, and apolipoproteins A-I and B in young growth hormone deficient subjects were measured at intervals during the five weeks after initial hormone-replacement therapy. The mean concentrations of cholesterol, apolipoproteins A-I and B decreased significantly during that period: the decreases were progressive and in similar proportion to each other. Also, the amount by which apolipoprotein A-I concentration decreased was correlated with its plasmas concentration before treatment. The data suggests that growth hormone may play a role in the regulation of these three major plasma lipoprotein components and tend to suppress the development of hypercholesterolemia which has been observed in some adult growth hormone deficient subjects.

Adolescent↗
PubMed1981

Studies on serum apolipoproteins and lipids in amniotic fluid and neonatal urine.

Amniotic fluid and neonatal urine were examined for the presence of lipids and serum apolipoproteins. Human apolipoproteins A-I, A-II, and ApoD found principally in serum high density lipoproteins were identified in both neonatal urine and amniotic fluid. A lecithin/sphingomyelin ratio of greater than 5 associated with fetal lung maturity was accompanied by the disappearance of A-II from amniotic fluid. Dissimilarities of total fatty acid composition of amniotic fluid when compared to cord serum or neonatal urine indicate other tissue sources for fatty acids found in amniotic fluid. In addition, the presence of serum apolipoproteins and lipids in both amniotic fluid and neonatal urine suggests that a least a portion of these constituents could be derived from fetal urine.

Amniotic Fluid↗
PubMed1981

1-Deamino-8-D-arginine vasopressin and urine cyclic adenosine monophosphate excretion in diabetes insipidus.

The response to 1-deamino-8-D-arginine vasopressin (DDAVP), an intranasally administered analogue of vasopressin, was investigated in children and adults with central diabetes insipidus. To assess the action of DDAVP on the distal nephron, cyclic adenosine monophosphate (cAMP) excretion was assayed in urine collected 4 hr before and during four subsequent 4-hr periods after intranasal administration of 5 micrograms DDAVP. Maximal effects on urine volume and concentration were observed between 4 and 12 hr, coinciding with an elevated cAMP excretion in seven subjects. The pretreatment 4-hr cAMP excretion (micrograms/gm creatinine) correlated inversely with age (p less than 0.02) and surface area (p less than 0.001). Subsequent cAMP excretion after DDAVP increased inconsistently with no relationship to duration of antidiuresis, indicating that urinary cAMP is a poor index of antidiuretic hormone action on the distal nephron. We also confirmed that DDAVP intranasally induces antidiuresis in patients with diabetes insipidus over approximately 12 hr.

Adolescent↗
PubMed1980

A pituitary abscess simulating an intrasellar tumor.

A 16-year-old girl presented with amenorrhea, polyuria, and thirst for eight months and severe headaches for two weeks. An intrasellar mass protruding above the sella turcica was demonstrated by pneumoencephalography. When the tumor was approached surgically by a transsphenoidal route, it was found that the sella turcica contained encapsulated purulent material under pressure. Ampicillin and methicillin had been given preoperatively, and postoperatively she required hormonal replacement therapy for anterior and posterior pituitary hypofunction.

Adenoma↗