Nutritional rickets still afflict children in north Texas.

Nutritional rickets is uncommon in North America, particularly in regions where sunlight is plentiful. Recent epidemics in North America occurred in dark-skinned toddlers with poor nutrition who had insufficient exposure to sunlight and whose parents were members of ethnic, social, and socioeconomic groups with predisposing practices. Nine children (8 toddlers and 1 infant) were referred to the Bone Metabolic Clinic at Texas Scottish Rite Hospital for suspected rickets between October 1997 and October 1998.

Recombinant interleukin-6 in the treatment of congenital thrombocytopenia associated with absent radii.

Purpose: The role interleukin-6 (IL-6) in the treatment of congenital thrombocytopenias is unknown. The purpose of this case report is to describe the efficacy of IL-6 in a child with thrombocytopenia with absent radii (TAR) syndrome.

Methods: A 23-month-old girl with TAR syndrome was treated with recombinant IL-6 (Sigosix; Serono Laboratories, Norwell, MA) at a dose of 7 micrograms/kg subcutaneously daily.

Maturation of rabbit proximal straight tubule chloride/base exchange.

The present in vitro microperfusion study compared the mechanism and rates of NaCl transport in neonatal and adult rabbit proximal straight tubules. In proximal straight tubules perfused with a late proximal tubular fluid and bathed in a serumlike albumin solution, the rate of volume absorption (JV) was 0.54 +/- 0.

Ontogeny of cyclooxygenase-1 and cyclooxygenase-2 gene expression in ovine lung.

Prostacyclin is a key mediator of pulmonary vascular and parenchymal function during late fetal and early postnatal life, and its synthesis in whole lung increases during that period. The rate-limiting enzyme in prostacyclin synthesis in the developing lung is cyclooxygenase (COX). We investigated the ontogeny and cellular localization of COX-1 (constitutive) and COX-2 (inducible) gene expression in lungs from late-gestation fetal lambs, 1-wk-old newborn lambs (NB1), and 1- to 4-mo-old newborn lambs (NB2).

Regulation of proximal tubule transport by angiotensin II.

Angiotensin II maintains extracellular volume homeostasis, in part, by regulating proximal tubule transport. Physiological doses of angiotensin II stimulate volume and solute transport in the proximal tubule independent of changes in the glomerular filtration rate. Stimulation of bicarbonate transport primarily occurs via increasing activity of the sodium/hydrogen exchanger and the sodium/bicarbonate cotransporter.

Actinomycotic splenic abscesses presenting with arthritis.

An 18-month-old Caucasian female began with a high fever. She developed swelling in one finger and one toe. Abdominal ultrasound revealed multiple abscesses in her spleen.

Early discharge of low-risk febrile neutropenic children and adolescents with cancer.

During the past decade, a relatively lower-risk patient population of febrile neutropenic children with cancer (over one-half of all these patients) has been identified. These patients can be safely discharged from the hospital before their absolute neutrophil count (ANC) exceeds 500/mm3. To evaluate the practice of early discharge of these patients, 580 consecutive episodes of chemotherapy-induced febrile neutropenia in 253 children and adolescents with cancer between June 1992 and May 1995 were reviewed.

Acute splenic complications in children with sickle cell-hemoglobin C disease.

Objective: To determine the frequency and severity of acute splenic complications in children and adolescents with sickle cell (SC) hemoglobin C disease.

Methods: The medical records of 271 patients with SC disease seen at our center were reviewed to evaluate the incidence and severity of acute complications involving the spleen.

Results: Sixteen (6%) children had acute splenic complications.

Cystic fibrosis presenting with hypokalemia and metabolic alkalosis in a previously healthy adolescent.

Cystic fibrosis (CF) is an exocrine disease affecting multiple organ systems. Patients with CF usually present with respiratory or gastrointestinal abnormalities. This study presents a case of a previously healthy 17-yr-old man who was diagnosed with CF after presenting with metabolic alkalosis and hypokalemia.

Effect of glucocorticoids on neonatal rabbit renal cortical sodium-inorganic phosphate messenger RNA and protein abundance.

Administration of glucocorticoids to neonates increases proximal tubule volume absorption by increasing glucose, bicarbonate, and amino acid transport. We have recently demonstrated that glucocorticoids may contribute to the maturational decrease in phosphate transport. This study examines the maturation of NaPi-6 [the regulated proximal tubule sodium-inorganic phosphate (Na-Pi) transporter] mRNA and protein abundance and the mechanism for the decrease in phosphate transport by glucocorticoids.

Calcium homeostasis and control of contractility in the developing heart.

The Ca2+ concentration within the myocyte is an important determinant of myocardial contractility. Substantial changes in the cellular processes responsible for transport of Ca2+ ions across the sarcolemmal and sarcoplasmic reticulum membranes occur during maturation of the heart. In this article, the mechanisms underlying these changes and their impact on myocardial performance are discussed in detail.

Protein losses in children on continuous cycler peritoneal dialysis.

Peritoneal dialysis can result in significant protein losses through the dialysate effluent. Although protein loss in chronic ambulatory peritoneal dialysis has been examined, it has not been extensively studied in patients on continuous cycler peritoneal dialysis. Such losses can contribute to protein calorie malnutrition, especially in infants and children, many of whom are on continuous cycler peritoneal dialysis.

Low-dose recombinant human granulocyte colony-stimulating factor therapy in children with symptomatic chronic idiopathic neutropenia.

Objectives: To prospectively define the lowest possible doses of recombinant human granulocyte colony-stimulating factor (rhG-CSF) that would benefit selected children with chronic idiopathic neutropenia whose disease was severe enough to interfere appreciably with quality of life.

Study Design: The efficacy of low-dose rhG-CSF therapy was investigated in six children with symptomatic chronic idiopathic neutropenia. All patients received rhG-CSF, 5 micrograms/kg subcutaneously, as a single daily dose until an absolute neutrophil count (ANC) above 1.

Noninvasive capnometry in a pediatric population with respiratory emergencies.

Objective: This study was designed to investigate the reliability, safety, and efficacy of measuring end tidal CO2 (ETCO2) in nonintubated pediatric patients presenting to an emergency department (ED) with respiratory emergencies.

Design/setting/patients: Eighty-five children were enrolled in a clinical, prospective, observational study at a university-affiliated children's hospital. Children age four weeks to 15.

Endogenous production of angiotensin II modulates rat proximal tubule transport.

There is evidence that angiotensin II is synthesized by the proximal tubule and secreted into the tubular lumen. This study examined the functional significance of endogenously produced angiotensin II on proximal tubule transport in male Sprague-Dawley rats. Addition of 10(-11), 10(-8), and 10(-6) M angiotensin II to the lumen of proximal convoluted tubules perfused in vivo had no effect on the rate of fluid reabsorption.

Maturation of rabbit proximal convoluted tubule chloride permeability.

Chloride transport in the rabbit proximal convoluted tubule (PCT) has components of active, transcellular, and passive, paracellular transport. The preferential reabsorption of bicarbonate and organic solutes by the early proximal tubule leaves the luminal fluid with a higher chloride concentration than that in the peritubular capillaries. Previous studies have suggested that solute permeability of the paracellular pathway may be higher in the neonatal PCT and that the neonatal proximal tubule reabsorbs solutes by passive mechanisms to a greater extent than the adult segment.

Quantitative relationship between brain temperature and energy utilization rate measured in vivo using 31P and 1H magnetic resonance spectroscopy.

In neonatal and adult animals, modest reduction in brain temperature (2-3 degrees C) during ischemia and hypoxia-ischemia provides partial or complete neuroprotection. One potential mechanism for this effect is a decrease in brain energy utilization rate with consequent preservation of brain ATP, as occurs with profound hypothermia. To determine the extent to which modest hypothermia is associated with a decrease in brain energy utilization rate, in vivo 31P and 1H magnetic resonance spectroscopy (MRS) was used to measure the rate of change in brain concentration of phosphocreatine, nucleoside triphosphate, and lactate after complete ischemia induced by cardiac arrest in 11 piglets (8-16 d).

Resolution of hepatitis B virus-related membranoproliferative glomerulonephritis after orthotopic liver transplantation.

The most well-described renal disease associated with hepatitis B virus (HBV) infection is membranous glomerulonephritis; membranoproliferative glomerulonephritis is described much less frequently. The course of HBV-associated renal disease after liver transplantation has not been described to date. We present a 15-year-old girl with HBV-associated membranoproliferative glomerulonephritis and end-stage liver disease, in whom, after cadaver liver transplantation, clinical and histological resolution of renal disease was observed.

Bacteremia in children with sickle hemoglobin C disease and sickle beta(+)-thalassemia: is prophylactic penicillin necessary?

Objective: To characterize the incidence of bacteremia and its potential for progression to septicemia in children with sickle hemoglobin C disease and sickle beta(+)-thalassemia to assess the need for penicillin prophylaxis.

Study Design: Retrospective chart review of the frequency and natural history of bloodstream infection in such patients not receiving prophylactic penicillin therapy and followed up in a single institution.

Results: During more than 842 patient-years of observation in 242 patients with sickle hemoglobin C disease, 15 episodes of bacteremia occurred in nine patients.

Stimulation of proximal convoluted tubule phosphate transport by epidermal growth factor: signal transduction.

The present study investigated the signal-transduction pathway responsible for the epidermal growth factor (EGF) stimulation of phosphate transport (JPhos) in the rabbit proximal convoluted tubule (PCT). Genistein, 10(-4) M, bath and lumen, an inhibitor of EGF receptor tyrosine kinase activity, blocked the EGF effect on JPhos, consistent with a role for tyrosine kinase in the signal-transduction pathway. Both staurosporine (5 x 10(-8) M) and calphostin C (10(-8) M), inhibitors of protein kinase C, blocked the EGF stimulation of JPhos, indicating that protein kinase C is involved in EGF signaling.

Randomized comparison of atenolol and fludrocortisone acetate in the treatment of pediatric neurally mediated syncope.

Overall, these results indicate that oral treatment of neurally mediated syncope is safe and efficacious. Further randomized trials in children will be required to determine the significance of a placebo effect, as well as potential differences in results related to the mechanism of syncope.

Effect of phosphorus supply on mineral balance at high calcium intakes in very low birth weight infants.

To evaluate the effect of varying phosphorus intake with constant high calcium intake (430 micrograms/kJ, or 180 mg/100 kcal), we randomly assigned 35 appropriate-for-gestational-age healthy male infants (birth weight, 715-1510 g) on day 21 postnatally to either standard-phosphorus (215 micrograms/kJ, or 90 mg/100 kcal), moderate-phosphorus (254 micrograms/kJ, or 106 mg/100 kcal), or high-phosphorus intake (287 micrograms/kJ, or 120 mg/100 kcal). Three-day mineral balances were determined after 7 d of the study diets. Weight and head circumference gain and intake of energy and vitamin D were not different for all groups.

Neonatal ischemic neuroprotection by modest hypothermia is associated with attenuated brain acidosis.

Background And Purpose: A 2.9 degrees C reduction in the intraischemic rectal temperature of neonatal piglets is associated with less brain damage compared with animals with normothermic rectal temperatures. This investigation studied one potential mechanism for this observation: better maintenance of energy stores and less brain acidosis secondary to reduced metabolic activity associated with modest hypothermia.

Identification of a point mutation in the folate receptor gene that confers a dominant negative phenotype.

UM-SCC-38 cells, a squamous cell carcinoma cell line of the head and neck, express limited amounts of folate receptor alpha antigen which is not capable of binding either folic acid or 5-methyltetrahydrofolic acid. Three distinct mutations in the open reading frame of the folate receptor were identified. We now show that the three mutants are nonfunctional with respect to folic acid binding because the protein products do not bind folate.