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Biomedical subjects

Daniel E Hale

Publications and source records attributed to Daniel E Hale.

11 recordsLinked to original sources

The changing spectrum of diabetes in Mexican American youth.

Type 2 diabetes (T2DM) is now a pediatric disease. As in adults, it disproportionately affects ethnic and racial minorities, including Hispanics. The preponderance of Hispanics in south Texas are of Mexican American (MA) heritage. Over the past 16 years, we have accumulated a large cohort of children with diabetes. We have noted distinct differences in numerous parameters between MA children with T2DM and those with type 1 diabetes (T1DM). In order to explore these observations, we have reviewed the records of all children diagnosed with diabetes (n = 669) during the 9 years between January, 1990 and December, 1998 and seen by our pediatric diabetes group. In this cohort were 329 MA, 287 non-Hispanic whites (EA) and 53 African Americans. Compared to EA children with T1DM, MA children were more likely to have a parent with diabetes, to be hospitalized at the time of diagnosis and to lack health insurance. The differences between MA children with T1DM and T2DM were significant: specifically, children with T2DM were more likely to be female and pubertal with a body mass index >25 kg/m(2) and have acanthosis nigricans. Slightly more than 2/3 of the MA children with T2DM had at least one parent already diagnosed with T2DM. Less than 1/3 of the children with T2DM required hospitalization at the time of diagnosis and only a 1/4 have private health insurance. Over this 9-year interval, the apparent incidence of diabetes almost tripled in south Texas with the great majority of that increase due to the increasing numbers of children with T2DM.

Child↗

Growth hormone benefits children with 18q deletions.

Most individuals with constitutional deletions of chromosome 18q have developmental delays, dysmyelination of the brain, and growth failure due to growth hormone deficiency. We monitored the effects of growth hormone treatment by evaluating 23 individuals for changes in growth, nonverbal intelligence quotient (nIQ), and quantitative brain MRI changes. Over an average of 37 months, the treated group of 13 children had an average nIQ increase of 17 points, an increase in height standard deviation score of 1.7, and significant change in T1 relaxation times in the caudate and frontal white matter. Cognitive changes of this magnitude are clinically significant and are anticipated to have an effect on the long-term outcomes for the treated individuals.

Abnormalities, Multiple↗

The spectrum of thyroid abnormalities in individuals with 18q deletions.

Chromosome 18q deletions (18q-) are survivable autosomal deletions, having an estimated incidence of one in 40,000 live births. Our long-term goals were to 1) comprehensively define the endocrine phenotype, 2) determine the natural history, and 3) identify key genes leading to particular phenotypes. This report specifically emphasizes the thyroid phenotype. Medical record review and comprehensive clinical assessment(s) were performed on 120 individuals with 18q- at the Chromosome 18 Clinical Research Center, the largest group of individuals with 18q- ever assembled. Affected subjects ranged in age from 6 wk to 32 yr at initial assessment. Due to case reports of thyroid dysfunction in 18q deletions and the well-established association between hypothyroidism and aneusomies, we undertook thyroid testing in all individuals and completed TRH studies on 50 of them. Our studies demonstrated that 12% had hypothyroidism, and the results were consistent with primary thyroidal dysfunction. Furthermore, two individuals progressed from normal to abnormal over the course of 2 yr. Based on these studies, it appears that, as is the case in other aneusomies, annual thyroid testing, using TSH as a primary screening tool, is indicated. The mechanism of the hypothyroidism is not yet known, and the genetic basis has not been delineated.

Adult↗

Mapping structural differences of the corpus callosum in individuals with 18q deletions using targetless regional spatial normalization.

Individuals with a constitutional chromosome abnormality consisting of a deletion of a portion of the long arm of chromosome 18 (18q-) have a high incidence ( approximately 95%) of dysmyelination. Neuroradiologic findings in affected children report a smaller corpus callosum, but this finding has not been quantified. This is in part due to the large intersubject variability of the corpus callosum size and shape and the small number of subjects with 18q-, which leads to low statistical power for comparison with typically developing children. An analysis method called targetless spatial normalization (TSN) was used to improve the sensitivity of statistical testing. TSN converges all images in a group into what is referred as group common space. The group common space conserves common shape, size, and orientation while reducing intragroup variability. TSN in conjunction with a Witelson vertical partitioning scheme was used to assess differences in corpus callosum size between 12 children with 18q- and 12 age-matched normal controls. Significant global and regional differences in corpus callosum size were seen. The 18q- group showed an overall smaller (25%) corpus callosum (P < 10(-7)), even after correction for differences in brain size. Regionally, the posterior portions of corpus callosum (posterior midbody, isthmus, and splenium), which contain heavily myelinated fibers, were found to be 25% smaller in the population with 18q-.

Agenesis of Corpus Callosum↗

Cognitive ability predicts degree of genetic abnormality in participants with 18q deletions.

One of the most common chromosomal deletions is a loss of genetic material from the long arm of chromosome 18. Most individuals with this condition exhibit mental retardation (68%), yet previous attempts to link cognitive status to deletion size have not shown an association, possibly because cases with additional genetic abnormalities were included. We studied 46 participants ranging from 3 to 35 years of age who had a pure genetic abnormality by excluding those with mosaicism or complex genetic rearrangements. Our patients had terminal deletions ranging from a proximal breakpoint at 18q21.1 (greater genetic abnormality, larger deletion size) to a more distal breakpoint at 18q23 characterized with molecular genetic techniques. Cognitive ability, assessed with the age-appropriate measure (Bayley, 1993 , Differential Ability Scale, Wechsler Scales), ranged from IQ = 49 to 113, with a predominance of mild and moderate mental retardation. Using multivariate regression, deletion size breakpoint rank order was predicted by cognitive ability, age, and adaptive behavior (Vineland Adaptive Behavior Scales), accounting for 36% of the variance in deletion size. However, lower cognitive ability (beta = .34, p = .032) and younger age (beta = .296, p = .024) predicted a larger deletion size, but adaptive behavior (beta = .225, p = .15) did not. An additional multivariate regression showed that cognitive ability and age together accounted for 33% of the variance in deletion size, whereas univariate regression showed that cognitive ability accounted for 26% of the variance and age accounted for 11% of the variance. These findings suggest that degree of cognitive impairment is associated with genetic abnormality when a large sample of individuals with "pure" deletions of genetic material from chromosome 18 is examined.

Adaptation, Psychological↗

Myelination in children with partial deletions of chromosome 18q.

BACKGROUND AND PURPOSE: We compared myelin levels in white matter (WM) in typically developing children with those of children with partial deletions of chromosome 18q (18q-). METHODS: Conventional spin-echo MR imaging at 1.9T was used to acquire T1-, T2-, and proton density-weighted images of the brain. From these images, a three-pool model was used to estimate the fraction of water in myelin, myelinated axon, and mixed water compartments (or pools) in six WM regions. A model curve was fit to the pool fractions to model the trend of myelin development by age in each region. Water-pool fractions in children with 18q- aged 5 months to 13 years were compared with those of age-matched, typically developing children. RESULTS: In children with 18q-, the model predicted later onset of myelination (P <.02), lower myelination rates (P <.001), and smaller equilibrium myelin pool fractions (P <.001). Significant differences were seen between the two groups for all three water pool fractions (P <.001). The mixed pool fraction was larger in children with 18q-. Although the myelin pool fraction was significantly smaller, the myelinated axon pool fraction was only slightly smaller, leading to a significantly smaller estimate of myelin per myelinated axon in children with 18q- (P <.001). CONCLUSION: Myelination modeling in 18q- children indicated delayed onset, a lower rate of myelination, and equilibrium myelin levels less than 50% those of age-matched, typically developing children.

Axons↗

Impact of the Bienestar school-based diabetes mellitus prevention program on fasting capillary glucose levels: a randomized controlled trial.

OBJECTIVE: To evaluate the impact of a school-based diabetes mellitus prevention program on low-income fourth-grade Mexican American children. DESIGN: A randomized controlled trial with 13 intervention and 14 control schools. SETTING: Elementary schools in inner-city neighborhoods in San Antonio, Tex. PARTICIPANTS: Eighty percent of participants were Mexican American and 94% were from economically disadvantaged households. Baseline and follow-up measures were collected from 1419 (713 intervention and 706 control) and 1221 (619 intervention and 602 control) fourth-grade children, respectively. INTERVENTION: The Bienestar Health Program consists of a health class and physical education curriculum, a family program, a school cafeteria program, and an after-school health club. The objectives are to decrease dietary saturated fat intake, increase dietary fiber intake, and increase physical activity. MAIN OUTCOME MEASURES: The primary end point was fasting capillary glucose level, and the secondary end points were percentage of body fat, physical fitness level, dietary fiber intake, and dietary saturated fat intake. Fasting capillary glucose level, bioelectric impedance, modified Harvard step test, three 24-hour dietary recalls, weight, and height were collected at baseline and 8 months later. RESULTS: Children in the intervention arm attended an average of 32 Bienestar sessions. Mean fasting capillary glucose levels decreased in intervention schools and increased in control schools after adjusting for covariates (-2.24 mg/dL [0.12 mmol/L]; 95% confidence interval, -6.53 to 2.05 [-0.36 to 0.11 mmol/L]; P =.03). Fitness scores (P =.04) and dietary fiber intake (P =.009) significantly increased in intervention children and decreased in control children. Percentage of body fat (P =.56) and dietary saturated fat intake (P =.52) did not differ significantly between intervention and control children. CONCLUSION: This intervention showed some positive results, but additional research is needed to examine long-term benefits, translation, and cost-effectiveness.

Biomarkers↗

Type 2 diabetes and diabetes risk factors in children and adolescents.

Long considered a disease of older adults, type 2 diabetes mellitus (DM) is now affecting children. While the prevalence and incidence of type 2 DM are not yet established in children, the number of affected individuals continues to climb. At the same time, obesity, the primary risk factor for type 2 DM, has become epidemic, affecting all ethnic and demographic groups across the United States. The lifestyle trends contributing to both of these phenomena include changes in dietary patterns and habits, declining levels of physical activity, and increasing sedentary behaviors. In response to these problems, the medical profession must become proactive with its patients and in the community.

Adolescent↗

Insulins and oral hypoglycemic medications.

The management of childhood diabetes is rapidly evolving, reflecting both the recognition of new types of diabetes in pediatrics and the availability of new insulins. Over the past two decades there have been increasing numbers of children affected by type 2 diabetes, maturity onset diabetes of youth (MODY), and medical diabetes secondary to medication usage (e.g. prednisone) or disease process (e.g., cystic fibrosis). These forms of diabetes require familiarity with medications other than insulin and an understanding of appropriate treatment strategies. Simultaneously, after years of little change, there has been the relatively rapid introduction of new insulins (e.g., lispro, aspart, glargine) and more sophisticated means of insulin delivery (e.g., pumps, pens, inhalers). Taken as a whole, these trends present a challenge to the pediatric diabetes specialist. In this article, the medications that are now frequently used in diabetes treatment are reviewed, including the indications for use, the usual dose, dose adjustment strategies, common side effects and anticipated outcomes. The diabetes literature on the new insulins and diabetes medications is reviewed, with an emphasis on the limited pediatric data. The goal is to familiarize the practicing pediatric diabetes specialist with these medications and their usage.

Administration, Oral↗

Molecular characterization of a patient with central nervous system dysmyelination and cryptic unbalanced translocation between chromosomes 4q and 18q.

We report on a 12-year-old boy who presented with delayed development and CNS dysmyelination. Genetic studies showed a normal 46,XY karyotype by routine cytogenetic analysis, and 46,XY.ish del(18)(q23)(D18Z1+, MBP-) by FISH using a locus-specific probe for the MBP gene (18q23). Though the patient appeared to have normal chromosome 18s by repeated high resolution banding analysis, his clinical features were suggestive of a deletion of 18q. These included hearing loss secondary to stenosis of the external auditory canals, abnormal facial features, and foot deformities. FISH studies with genomic probes from 18q22.3 to 18qter confirmed a cryptic deletion which encompassed the MBP gene. In an attempt to further characterize the deletion, whole genome screening was conducted using array based comparative genomic hybridization (array CGH) analysis. The array CGH data not only confirmed a cryptic deletion in the 18q22.3 to 18qter region of approximately 7 Mb, it also showed a previously undetected 3.7 Mb gain of 4q material. FISH studies demonstrated that the gained 4q material was translocated distal to the 18qter deletion breakpoint. The 18q deletion contains, in addition to MBP, other known genes including CYB5, ZNF236, GALR1, and NFATC1, while the gained 4q material includes the genes FACL1 and 2, KLKB1, F11 and MTNR1A. The use of these combined methodologies has resulted in the first reported case in which array CGH has been used to characterize a congenital chromosomal abnormality, highlighting the need for innovative molecular cytogenetic techniques in the diagnosis of patients with idiopathic neurological abnormalities.

Central Nervous System↗