Warren B. Karp

Visceral adipose tissue and cardiovascular risk factors in obese children

OBJECTIVE In adults visceral adipose tissue (VAT) has been shown to be more highly correlated with cardiovascular (CV) risk factors than are other measures of adiposity such as subcutaneous abdominal adipose tissue (SAAT), percent body fat (%BF), or total body fat mass (TFM). We examined the relations between these measures of fatness and CV risk factors in obese children. STUDY DESIGN Subjects were 64 obese (27% to 61% BF) children (24 black girls, 19 white girls, 11 black boys, 10 white boys) aged 7 to 11 years. VAT and SAAT were measured with magnetic resonance imaging. TFM and %BF were determined with dual x-ray absorptiometry. Hierarchical stepwise multiple regression analyses were used to determine the proportions of variance in CV risk factors explained by the demographic and adiposity measures. RESULTS VAT but not SAAT, %BF, or TFM explained a significant proportion of the variance (r2 range = 0.10 to 0.21) in several lipid/lipoprotein risk factors including triacylglycerols, high-density lipoprotein cholesterol, the ratio of total cholesterol to high-density lipoprotein cholesterol, and low-density lipoprotein particle size. CONCLUSION Many of the deleterious relations between VAT and lipid/lipoprotein risk factors seen in adults were already present in this sample of obese children.

Use of telemedicine for children with special health care needs

Objective. In 1995, the Childrens Medical Services (CMS) of the State of Georgia contracted with the Department of Pediatrics of the Medical College of Georgia (MCG) and the MCG Telemedicine Center to develop telemedicine programs to provide subspecialty care for children with special health care needs. This article presents project statistics and results of client evaluation of services, as well as physician faculty attitudes toward telemedicine. Design. A demonstration project using telemedicine between a tertiary center and a rural clinic serving children with special health care needs was established. Data were collected and analyzed for December 12, 1995 to May 31, 1997, during which 333 CMS telemedicine consultations were performed. Results. Most CMS telemedicine consultations (35%) involved pediatric allergy/immunology. Other subspecialties included pulmonology (29%), neurology (19%), and genetics (16%). Overall, patients were satisfied with the services received. Initially, physician faculty members were generally positive but conservative in their attitudes toward using telemedicine for delivering clinical consultation. After a years exposure and/or experience with telemedicine, 28% were more positive, 66% were the same, and only 4% were more negative about telemedicine. The more physicians used telemedicine, the more positive they were about it (r = .30). Conclusions. In terms of family attitudes and individual care, telemedicine is an acceptable means of delivering specific pediatric subspecialty consultation services to children with special health care needs, living in rural areas distant to tertiary centers. Telemedicine is more likely to be successful as part of an integrated health services delivery than when it is the sole mode used for delivery of care.

Correlation of human placental enzymatic activity with trace metal concentration in placentas from three geographical locations

Abstract Fifty-eight placentas from three cities were assayed for the activities of carnitine palmityltransferase, steroid sulfatase, benzpyrene hydroxylase, (NAD + ) isocitric dehydrogenase, and (NADP + ) glucose-6-phosphate dehydrogenase. Trace metal analyses were also performed. There were significant differences in enzymatic activities between cities which correlate with the trace metal levels.

Tryptophan metabolism in acrodermatitis enteropathica

Tryptophan-loading tests were performed on two normal subjects before and after diiodohydroxyquin treatment and on three acrodermatitis enteropathica patients being treated with diiodohydroxyquin. Patients who received a loading dose of tryptophan had higher urinary levels of kynurenine, kynurenic acid, and acetylkynurenine in comparison with normal subjects; 3-hydroxykynurenine and N-methylnicotinamide values were lower in patients than in control subjects. A possible explanation for these results would be a decreased activity of kynurenine hydroxylase in the patients.

The Effect of Hydrocortisone, Thyroxine, and Phenobarbital on Diamine Oxidase Activity in Newborn Rat Intestine

ABSTRACT: There is a reported association between administration of prenatal glucocorticoids and a decreased incidence of necrotizing enterocolitis in human infants. In rats, the degree of ischemic bowel disease correlates negatively with intestinal diamine oxidase (E.C. 1.4.3.6) activity. Since the administration of hydrocortisone, thyroxine, or phenobarbital to newborn rat pups affects the development of intestinal enzymes, we were interested in knowing whether hydrocortisone, thyroxine, or phenobarbital specifically affect intestinal diamine oxidase activity. We injected rat pups with hydrocortisone sodium succinate, 1- thyroxine pentahydrate, sodium salt, sodium phenobarbital, or the control solution on days 4, 6, 8, or 10 of life (phenobarbital, days 3, 5, 7, or 9). Pups were injected 3 days consecutively (phenobarbital, 4 days), and all were sacrificed on days 7, 9, 11, and 13. Intestinal diamine oxidase and intestinal invertase (E.C. 3.2.1.26) activities were measured. Invertase was used as a control enzyme because it is known to be induced by glucocorticoid hormones. We found that the hydrocortisone-injected pups had 10-fold higher specific activity of invertase than the saline-injected animals. Diamine oxidase activity was significantly higher in the group receiving hydrocortisone and sacrificed on days 7, 9, and 11. Enzyme activity in both the hydrocortisone-injected and saline-injected groups was equal on day 13, as was enzyme activity on all days in the thyroxine-injected and sodium hydroxide-injected groups, and the phenobarbital-injected and the saline-injected groups. Our results suggest that diamine oxidase activity may be induced by hydrocortisone, but is not affected by thyroxine or phenobarbital.

Comparison of the binding characteristics of serum albumins from various animal species.

In order to develop an animal model to study the bilirubin displacing effect of various drugs, we compared the bilirubin binding ability of human, pig, dog, rabbit, hamster, rat, guinea pig, and cat albumin. These albumins were used also to study the binding of monoacetyldiaminodiphenyl sulfone (MADDS). Using human, rat, guinea pig, and rabbit albumin, we studied the effect of sulfisoxazole, ceftriaxone, and tin protoporphyrin on bilirubin binding. Our results demonstrate that each animal albumin has different binding characteristics for the various chemicals tested. This variable must be considered before using an animal as a model for studying factors influencing bilirubin deposition in the brain.

Comparison of the bilirubin concentration and the bilirubin/albumin ratio with the bilirubin-binding ability in neonatal serum☆☆☆★

The bilirubin-binding ability of neonatal serum was measured and compared with the serum bilirubin concentration and the serum bilirubin/albumin ratio. The bilirubin/albumin ratio correlated no better with the bilirubin-binding ability than the bilirubin concentration alone.

Drugs Affecting Bilirubin Uptake by Human Erythrocyte Ghosts

Drugs known to affect the red blood cell membrane and used clinically in neonates were tested for their ability to cause increased 14C-bilirubin uptake by erythrocyte ghosts. The additional uptake of bilirubin by ghosts in the presence of penicillin G, phenobarbital, furosemide and theophylline may be explained by the effect of these drugs on free bilirubin levels as measured with a horseradish peroxidase assay. In contrast, the effect of chlorpromazine in causing increased bilirubin uptake by ghosts could not be totally explained by either ghost lysis or increased free bilirubin levels, as measured by light scattering, and was due to a direct effect of chlorpromazine on the ghost membrane. Our results demonstrate that drugs may act through different mechanisms in causing increased bilirubin uptake by erythrocytes.

Human Placental Amino Acid Oxidation

Uniformly labeled L -alanine, L -aspartic acid, L -glutamic acid, and glycine were incubated with placental ‘mitochondria’ from normal pregnancies

Albumin Binding of Bumetanide

Bumetanide binding to human serum albumin was studied using ultrafiltration. The first stoichiometric binding constant for bumetanide is 6.4 X 10(4) M-1. Bumetanide competes with bilirubin for human serum albumin binding, having a KDispl (displacement constant) of 6.2 X 10(3) M-1 measured by the peroxidase method. This displacement effect is also observed using pooled umbilical cord serum and pooled adult serum employing a dialysis rate method. Bumetanide competes to a lesser degree with diazepam binding to human serum albumin. No competition with diazepam occurs using umbilical cord or adult serum. Pharmacologic concentrations of bumetanide would not significantly affect bilirubin-albumin binding and should not increase the risk of bilirubin encephalopathy in newborn infants.