Immunoassay of insulin-like growth factor-binding protein-3 (IGFBP-3): new means to quantifying IGFBP-3 proteolysis

Posttranslational modifications, particularly proteolysis, may play a significant role in the regulation of insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) physiology, and thus, measurement of modified variants of IGFBP-3 and/or their combination ratios may have important research and diagnostic relevance. Based on evaluation of a panel of monoclonal and polyclonal IGFBP-3 antibodies, we constructed three new enzyme-linked immunosorbent assays (ELISAs) using a common capture and polyclonal (ELISA-3) or monoclonal (ELISA-1 and -2) detection antibodies and evaluated them in a two-step colorimetric procedure. Evaluation of ELISA-1-3 demonstrated detection limit, dynamic range, overall precision, and recovery of the added IGFBP-3 to be generally less than 0.04 microg/L, 2-100 microg/L, less than 10%, and 91-113%, respectively. IGF-I and -II, and IGFBP-1, -2, -4, -5, and -6 did not interfere. In normal adult sera (n = 26), seminal plasma (n = 14), pregnancy sera (n = 30), and amniotic fluid (n = 30), ELISA-1-3 detected significantly different IGFBP-3 levels (by up to 6-fold, on the average), whereas levels in seminal plasma determined by ELISA-1 were undetectable. Comparison of the values obtained vs. corresponding levels by an established method (Diagnostic Systems Laboratories, Inc., active IGFBP-3 ELISA) were similarly sample dependent and, on the average, varied by up to 19-fold. Only ELISA-3 compared well with the Diagnostic Systems Laboratories, Inc., IGFBP-3 ELISA when samples from normal adults were analyzed. The observed variability could not be totally explained by 50% lower reactivity of ELISA-1-3 for glycosylated IGFBP-3 vs. the nonglycosylated form, and changes in phosphorylation had no effect on immunoreactivity. Evaluation of IGFBP-3 after proteolysis by seminal plasma, plasmin, or thrombin suggested recognition of intact IGFBP-3 by ELISA-1, whereas ELISA-3 appeared to measure intact and proteolyzed IGFBP-3 (total IGFBP-3) with similar potency. In contrast, levels determined by ELISA-2 increased severalfold, indicating preferential recognition of IGFBP-3 fragments. We propose that immunoassay capable of differential determination of IGFBP-3 variants may help better define the physiological importance and potential clinical value of IGFBP-3 measurements.     

Enzymologic studies on patients with methylmalonic aciduria: basis for a clinical trial of deoxyadenosylcobalamin in a hydroxocobalamin-unresponsive patient.

Eleven patients with methylmalonic aciduria have been classified on the basis of detailed enzymology on cultured skin fibroblasts. Nine were classified as mutase deficiencies and were unresponsive to hydroxocobalamin in vivo or in vitro. One was classified as a Cbl A variant and was responsive to hydroxocobalamin therapy in vitro and in vivo. Patient 11 was classified as having deoxyadenosyltransferase deficiency (Cbl B). However, a clinical therapeutic trial of deoxyadenosylcobalamin resulted in no clinical or biochemical improvement. Further studies on the patient's cultured fibroblasts suggested that deoxyadenosylcobalamin fails to reach the mitochondria in an intact form. These studies show that detailed enzymologic classification is essential for the reliable evaluation of the response to therapeutic maneuvers; complementation studies alone may be inadequate to completely classify these patients. Therapy with deoxyadenosylcobalamin offers no advantages over the use of hydroxocobalamin in the treatment of patients with methylmalonic aciduria.     

Melanotic neuroectodermal tumor of infancy: Report of a case with ganglionic differentiation

Melanotic neuroectodermal tumor of infancy (MNTI) is a rare but well-documented lesion of neuroectodermal derivation. Maturation of the neural elements has been reported only occasionally. We report a case of MNTI of the maxilla showing maturation of neural elements to ganglionic cells. © Wiley-Liss, Inc.     

Autonomous aldosterone-secreting ovarian tumor

The case of a young woman with primary aldosteronism originating extraadrenally--ovarian tumor--is reported. Clinically she presented with uncontrolled hypertension. Biochemical and hormonal profiles showed features of aldosteronism. The primary was found in the left ovary. Following excision of the tumor, aldosteronism regressed completely. Microscopically, the tumor was of the lipid cell type. Nine months after surgery she is asymptomatic and well. Review of the literature uncovered three previous reports of aldosterone-secreting ovarian tumors.     

Response to oral β-carotene supplementation in patients with cystic fibrosis: a 16-month follow-up study

The aim of this study was to determine the efficacy of long-term oral β -carotene supplementation for correcting impaired β -carotene status in cystic fibrosis patients. Thirty-five patients (2.3-30.5 years of age) with coefficients of fat absorption of 46-96% (median 88%) received β -carotene 0.5 mg/kg daily and were followed over a 16-month treatment period. Baseline plasma β -carotene concentrations in patients (meanSD, 0.090.06 μ mol/1) were significantly lower than those of age-matched controls (0.860.56 μ mol/1) ( p < 0.0001). Concentrations increased rapidly and reached a plateau at or before 3 weeks that was maintained throughout the study period. Values obtained at 3 weeks (0.890.64 μ mol/1) were significantly higher ( p < 0.0001) than those at baseline and did not differ from controls. Plasma retinol and α -tocopherol concentrations increased during the observation period, but remained within normal ranges. Plasma retinyl palmitate, which was below the detection limit in all but one patient at baseline, did not increase. Thus oral β -carotene supplementation is effective and normalizes β -carotene status of cystic fibrosis patients without evidence of significant side effects. β -Carotene, cystic fibrosis, LDL-cholesterol, oral supplementation, retinol, α-tocopherol     

Amniotic fluid composition in abnormal pregnancies

The amniotic fluid composition of 74 pregnant women having abnormalities was compared with those of 70 normal pregnant women. Women having small for gestational age children showed a decrease of creatinine level and an increase of locithin to sphingomyelin (L/S) ratio. Anomic mothers had higher alkaline phosphatase. The calcium and creatinine were decreased and protein was increased in amniotic fluid of premature deliveries.     

Elevated Serum Alpha Fetoprotein and Normal Liquor Alpha Fetoprotein Values in Association with an Abdominal Pregnancy

Summary: A case report is described in which abdominal pregnancy was misdiagnosed by ultrasound scanning as a pregnancy within a horn of a bicornuate uterus. Two serum alpha fetoprotein (SAFP) results were greatly elevated and an amniocentesis was performed, the liquor alpha fetoprotein (LAFP) and karyotype were normal. Elective Caesarean section was performed at 38 weeks for a persistent transverse lie and an abdominal pregnancy was found. The outcome was excellent for both the mother and child.
This is the first reported case of amniocentesis and measurement of LAFP in an abdominal pregnancy and confirms abdominal pregnancy as a rare cause of an elevated SAFP.     

Screening for a raised rectal temperature in Africa

The main purpose of this study was to compare rectal and axillary temperature measurements in African children. Altogether 573 sick children were seen in an outpatient setting in rural West Africa. Rectal and axillary temperatures were measured and the parent or guardian was asked if they thought that the child had a raised body temperature. Normal ranges were defined from an age matched population of 203 healthy children. A raised axillary temperature predicted a raised rectal temperature with a sensitivity of 98% and a specificity of 88%. The parents' impression that their child had a fever was a less sensitive (89%) and less specific (59%) indicator of raised rectal temperature. A raised axillary temperature is a good screening test for a raised rectal temperature in African children.     

Fibromatosis of bone in children

Radiographs, computed tomograms, and radionuclide bone scans were obtained preoperatively in three children with fibromatosis involving the bones and soft tissues of the extremities. Two of the children had identical scar-like bone lesions of the proximal tibia, which, to the authors' knowledge, have not been reported before in this disease. The lesions recurred in two children.     

Emphysema in the renal allograft

Two diabetic patients in whom emphysematous pyelonephritis developed after renal transplantation are described. Clinical recognition of this unusual and serious infection is masked by the effects of immunosuppression. Abdominal radiographic, ultrasound, and computed tomography findings are discussed. The clinical presentation includes urinary tract infection, sepsis, and acute tubular malfunction of the allograft in insulin-dependent diabetics.