摘要:

A peculiar human cell line (GI-ME-N) derived from the metastatic bone marrow of a 2-yr-old patient with stage IV neuroblastoma (NB) was extensively characterized. Cell-type-specific markers, tumorigenicity in nude mice, morphology, cytogenetics, and amplification/expression of the N-myc gene were evaluated. All metaphases presented the typical 1p deletion. Surface markers specific for NB cells, vimentin, and neurofilament proteins were all clearly detectable with immunofluorescence and/or western blot procedures. Moreover, it was found that GI-ME-N cells did not express N-myc oncogene or HLA class 1 antigens, and were not classified as peripheral neuroectodermal tumor cells. However, extremely short latency and survival times, comparable to peripheral neuroectodermal tumor cells, were observed in nude mice grafted with GI-ME-N. In addition, no correlations were. observed in tumorigenicity of N-myc amplified (IMR32)versusunamplified (SK-N-SH GI-ME-N) human NB cell lines in nude mice. We conclude that N-myc amplification/ expression do not correlate with the aggressiveness of human NB in athymic animals, which is not always explained by the peripheral neuroectodermal tumor cell nature of the malignant cells, either.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The ability of peripheral blood mononuclear cells (PBMC) from newborn infants, gestational age 24- 42 wk, to produce interferon-a (IFN-α) on the first day after birth was studied in vitro. Human amnion cells (WISH) coated with herpes simplex virus type I and fixed by glutaraldehyde were used as IFN-α inducers. Individual IFN-α producing cells (IPC) among PBMC were determined by an immunoplaque assay. The frequency of IPC was low in all premature (≤36 wk) infants (median 0.3 IPC/104PBMC, range 0.0-2.6), and significantly higher (median 2.0 IPC/104PBMC, range 0.0-16.4) in term infants (>37 wk). The frequencies were lower in both groups of infants than in adults (7.3 IPC/104PBMC, range 2.0- 23.7). When a conditioned medium from cultures of herpes simplex virus type I-stimulated PBMC from adults was added to the IFN induction cultures, the frequencies of IPC increased in PBMC from both preterm and term infants, and in the latter group did not differ significantly from adult levels. The median production of IFN-α per IPC was 1.1 U (range 0.0-2.8) in premature infants, 1.0 U (range 0.0-8.8) in term infants and 3.2 U (range 1.5-8.0) were decreased, a decline of IPC frequencies occurred. This decline was more marked and started at higher PBMC concentrations in infants than in adults, and was prevented by addition of conditioned medium from herpes simplex virus type I-stimulated cultures of PBMC from adults. The results suggest that PBMC of preterm infants on the first day after birth are deficient both with respect to the proportion of actual IPC and to accessory mechanisms necessary for a normal IFN-αresponse. In contrast, IPC frequencies in term infants approach levels of adults, but accessory functions may still be deficient.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We describe a new method to measure human serum antibody against streptococcal erythrogenic toxins that uses inhibition of lymphocyte mitogenicity of the toxins as the indicator. Sera from 53% of 53 Kawasaki disease patients contained specific inhibitory activity against A toxin, whereas only 15% had serum inhibitory activity against B toxin. The specific anti-A toxin serum inhibitor was found in 10% of 118 age-matched control patients suffering from various infections and allergic diseases (p=0.001, compared to Kawasaki disease patients). Serum inhibitory activity was detected in a small number of patients withβ-hemolytic streptococcal infection (3/19) and in none of the age-matched healthy children (0/17). However, four of seven cord blood sera samples and five of 13 sera samples from healthy neonates contained the inhibitor, a result suggesting passive transfer from mothers. Most of the antimitogen-positive sera were also positive by ELISA of IgG antibody against A toxin, and IgG fractions of the positive sera remained positive in both assays. Thus, it is possible that the specific serum inhibitor detected by the antimitogen assay represents anti-A toxin antibody. The role of toxin-producing bacteria in the pathogenesis of Kawasaki disease remains to be investigated.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

To understand the relevance of subnormal serum concentrations of IgG2, we measured IgG2 in serum of 575 healthy children and identified 11 with concentrations > 2 SD less than the mean for age. The levels of IgG2 present were similar to those found in symptomatic children with IgG2 subclass deficiency associated with antibody deficiency. The 11 children ranged in age from 1 to 14 y (mean=5.7). Detailed clinical information was available on 10 of the 11 children and each was matched for age with two controls. The median number of visits/y to the doctor for infectious illnesses was identical for the two groups (1.0). Nine of the children with subnormal IgG2 were followed for 1 to 5 y (mean=2.3). All nine children had normal serum concentrations of IgA, IgGl, IgG3, and IgG4 but seven had persistently subnormal or low-normal serum IgG2 concentrations. One of these seven children also had a subnormal serum concentration of IgG, and one had subnormal IgM. Antibody responses to Haemophilus b polysaccharide vaccine were normal in five of six who were immunized. In vitro secretion of Ig by mitogen-stimulated peripheral blood mononuclear cells was measured in six of seven children with persistently subnormal or low-normal IgG2; five showed decreased secretion of IgG2, and two of the five also had subnormal secretion of IgGl and IgG3. An important implication of this study is that the subnormal concentrations of serum IgG2 found in infectionprone children are not a sufficient explanation for their increased susceptibility to infection. The healthy children with low serum concentrations of IgG2 differ from symptomatic children with subnormal IgG2 in that the former have otherwise normal serum Ig concentrations and have normal antibody responses to Hib PS vaccine.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

We evaluated the appropriateness of an animal model for the bronze baby syndrome. Ligation of the common bile duct in adult Wistar rats induces an accumulation of porphyrins and copper in the liver and a 20% conversion of protoporphyrin IX into Cu(II)-protoporphyrin IX. Upon irradiation of these animals with superblue lamps, the plasma content of Cu(II)-protoporphyrin increases by about 30%. Cholestasis also increases the recovery of porphyrins in the urine, although light treatment of ligated rats further increases urinary porphyrin excretion. The spectroscopic changes induced by irradiation of sera of ligated rats are consistent with the formation of products that have the typical spectrum found in bronze baby syndrome patients, i.e. a reduced absorbance in the visible region and an increased absorption in near-UV and red spectral regions. The products responsible for the brown discoloration found in bronze baby syndrome seem to result from phototransformation of copper-porphyrins subsequent to an electron transfer between photoexcited bilirubin and the copper ion.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Infants with extrahepatic biliary atresia (EHBA) commonly develop rickets in infancy, whereas long-term survivors with EHBA commonly develop osteopenia with increasing age. We evaluated baseline vitamin D (D2and D3), 25-OH vitamin D2and D3, 1,25(OH)2vitamin D, bone mineral content, and vitamin D2and 25- OH vitamin D3absorption in six infants and children (age 4-22 mo) with EHBA whose portoenterostomy failed to produce bile flow (group 1) and five infants and children (age 10/12 to 8-4/12 y) with EHBA whose portoenterostomy repair led to good postoperative bile flow (group 2). Baseline serum vitamin D2and D3were undetectable in all subjects in group 1 despite supplements of 2500-5000 IU/ day, whereas all group 2 subjects given supplements (doses 400-5000 IU/d) had measurable levels. Baseline serum 25-OH vitamin D was less than 15 ng/mL in five of six (three with rickets) in group 1, whereas only one in group 2 had concentrations less than 15 ng/mL. A significantly blunted rise of vitamin D2above baseline and reduced area under the absorption curve after 1000 IU/kg vitamin D2were found in group 1 patients compared to group 2 (both p<0.01), and five pediatric controls (both/*<0.01). The peak change and area under the absorption curve for serum 25-OH vitamin D3from baseline after 10µg/kg 25-OH vitamin D3 were significantly reduced for group 1 (both at least p<0.05) and group 2 compared to controls (both p<0.05). Malabsorption of supplemental doses of vitamin D compromises their efficacy to prevent rickets in infants with EHBA with poor bile flow after portoenterostomy. Despite severe malabsorption of vitamin D, we suggest that oral 25-OH vitamin D may be absorbed sufficiently to prevent rickets.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Longitudinal changes in selenium (Se) and protein concentrations and glutathione peroxidase (GSHPx) activity of milk collected from healthy mothers of term (n=12), preterm (n=10), and very preterm (n=12) infants were assessed. All infants were size appropriate for gestational age. Milk samples representative of colostrum (d 3), transitional (d 7), and mature milk (d 21 and 42) were assayed. The content of Se in the colostrum secreted by mothers of preterm infants was significantly greater than the Se content of milk secreted by the same mothers at d 21 and 42 of lactation. Mothers of term and very preterm infants, however, produced colostrum with significantly higher levels of Se than milk produced at d 7 (p<0.05), d 21 (p<0.01), or d 42 (p<0.001). Significant differences between the protein concentrations measured in early lactation and in late lactation were evident in all maternal groups. Protein content did not differ significantly among groups at anytime during lactation. An age-related difference was detected in milk GSH-Px activities of mature milk (d 21). Mature milk produced by mothers of very preterm infants on d 21 of lactation contained significantly greater enzyme activity (p<0.05) than milk produced by mothers of term infants at the same stage of lactation. Activity of GSH-Px in milk from mothers of very preterm and preterm infants paralleled previously noted changes in long-chain polyunsaturated fatty acid content in human milk with the progression of lactation. Although the function of GSH-Px in milk is unknown, results from this study suggest a possible role in the protection of milk lipids from oxidative damage.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The feasibility of using isotopic techniques to study Mg absorption and metabolism was explored in three full-term human infants.25Mg (98.8 atom %) was administered orally as an in vivo tracer. Fractional25Mg absorption, isotope retention, endogenous fecal Mg losses, and apparent Mg exchangeable pool size were then determined under three conditions of isotope administration:/) 20 mg25Mg, with single feeding; 2) 20 mg25Mg, distributed over a 24-h period; and 3) 60 mg25Mg, over a 24-h period. Mg isotope ratios were determined by inductively coupled plasma mass spectrometry. Fractional absorption was increased in all three infants after distributed versus bolus administration at the 20 mg dose; mean (±SD) fractional absorption was 64.0 ± 3.9 versus 54.3 ± 5.9%, respectively. 25Mg retention was also more in all three infants after distributed administration (55.8 ± 3.0 versus 44.3 ± 1.3% of dose). At the 60-mg25Mg dose, compared to 20 mg, fractional absorption was reduced but absolute isotope absorption more than doubled in all infants; urine isotope losses represented a similar fraction of the absorbed dose, thus,25Mg retention also more than doubled. Compared to the results of the isotope studies, net Mg absorption and balance were uninfluenced by total Mg intake. Isotope retention with distributed isotope administration resulted in measurable isotopic enrichment of plasma and erythrocytes at 72 h (i.e. plasma isotope enrichment was 6.3-10.2 and 19.2-23.5% for the 20- and 60-mg dose, respectively). With these doses, apparent Mg exchangeable pool size ranged from 5.5 to 7.6 mmol/kg body wt; these values showed a decrease with age both within and between infants. Our results indicate that Mg stable isotope studies may offer sufficient accuracy and reproducibility to permit meaningful investigations of Mg bioavailability and developmental changes in Mg metabolism in human infants.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

The metabolism of proteoglycans in normal growth plate and the changes in growth plate morphology induced by diabetes and malnutrition were studied in rats. The proteoglycans had a significantly faster turnover (half-life measured with [35S]sulfate labeling: 25-30 h) than the cells in the growth plate. Morphometric studies showed significant reductions of cell number, zone height, and [3H] thymidine incorporation in growth plates from rats with untreated streptozotocin-induced diabetes compared to normal rats. Similar, although less pronounced alterations were observed in malnourished, nondiabetic rats. Disaggregation and degradation of proteoglycans are probably necessary prerequisites for calcification. Our data indicate that the proteoglycans are in a dynamic state of rapid biosynthesis and degradation throughout the growth plate with a shift in the balance at the calcification front toward less synthesis and more degradation.

ISSN:0031-3998    

出版商:OVID    

年代:1990

数据来源: OVID