Choices, challenges, and constraints: a pragmatic examination of the limits of mental age matching in empirical research.

The work of Ed Zigler spans decades of research all singularly dedicated to using science to improve the lives of children facing different challenges. The focus of this article is on one of Zigler's numerous lines of work: advocating for the practice of mental age (MA) matching in empirical research, wherein groups of individuals are matched on the basis of developmental level, rather than chronological age. While MA matching practices represented a paradigm shift that provided the seeds from which the developmental approach to developmental disability sprouted, it is not without its own limits. Here, we examine and test the underlying assumption of linearity inherent in MA matching using three commonly used IQ measures. Results provide practical constraints of using MA matching, a solution which we hope refines future clinical and empirical practices, furthering Zigler's legacy of continued commitment to compassionate, meaningful, and rigorous science in the service of children.

[Microbeads and nanobeads in microscopy: a tool for spatial, spectral and dynamic settings. Application to molecular co-localization]. / Microbilles et nanobilles en microscopie: outil de réglage spatial, spectral et dynamique. Application à la colocalisation moléculaire.

This article illustrates a methodology which can be used on cellular and tissular specimens prepared with fluorochromes and analyzed by laser scanning confocal microscopy. Fluorescent beads are used to simulate the fluorochromes and they determine their detectability inside the preparations. They can also be used to verify that the microscopes are set properly so that the resulting images can be analyzed and are reliable to evaluate possible co- localizations. Methods of factor analysis are applied to optical section series obtained on the microscope to characterize the fluorochromes that are used to stain different locations of the specimen. Photophysical properties (emission spectra, decay rates) of the fluorochromes are used to obtain the differentiation. Section series are obtained either by spectral selection via a sequence of filters or by successive scans of the same specimen. Concerning the three- dimensional analysis, differentiation of series that are obtained by z displacement leads to the restoration of focal planes and improves the legibility of specimens. These planes which are not at the same depth when the excitation sources are not aligned can the be superimposed to achieve the co-localization.

[Microbeads, nanobeads and cytometry: applications to the analysis and purification of cells and biomolecules]. / Microbilles, nanobilles et cytométrie: applications à l'analyse et à la purification cellulaire et moléculaire.

Nano and microspheres are important tools in cytometry. They have been used in first to optimize fluorescent signals detected by flow cytometry and to evaluate phagocytosis. Some antigens were also detected by using nanospheres covalently coupled to antibodies. Specifically dedicated microspheres are now widely used for antigenic quantitation by flow cytometry, and magnetic nano and micropheres are very usefull for cellular and molecular purifications. To date, analytical methods based on the use of microspheres are developed to detect proteins, nucleic acids, and ions. To this end, antibodies, oligonucleotides, or chelating agents are bound to microspheres characterized by different fluorescences. The applications of these multiplexed microspheres assays allow to identify and quantify simultaneously some macromolecules and ions, but they also permit to analyze enzymatic activities and to perform polymorphism analyses. With microspheres used as reactive support, molecular analyses are therefore possible by flow cytometry. Nano and microspheres are also usefull tools for calibration in confocal microscopy as well as for micromanipulations of biomolecules and of living cells. Inovative methods based on the use of nano and microspheres are expected in the fields of biology, medicine, food industry, and environmental sciences.

Analysis of the distribution of MRI contrast agents in the livers of small animals by means of complementary microscopies.

BACKGROUND: Magnetic resonance imaging (MRI) contrast agents contain magnetic molecules such as iron (Fe) or gadolinium (Gd) that are injected in vivo into rats or mice to study their distribution inside the liver. Fluorescent europium (Eu) can be used as a model of Gd to obtain comparable information of this distribution of corresponding contrast agents. In a similar approach, Fe can be attached to Texas Red and used as a model of ferumoxides and be detected by fluorescence. METHODS: To combine and compare the advantages of different microscopic imaging modes, characterization studies were carried out by means of a confocal laser scanning microscope (CLSM), a secondary ion mass spectrometric (SIMS) microscope, and an electron energy loss spectrometric (EELS) microscope. In the case of CLSM, the locations of fluorescent signals inside preparations were determined by factor analysis of biomedical image sequences (FAMIS) and selection of image sequences at emission. RESULTS: By CLSM and FAMIS, we distinguished chelated Eu and Texas Red attached to Fe. By SIMS microscopy, we distinguished Eu and Gd of chlorides and chelates and Fe of a ferumoxide. By EELS microscopy, we distinguished Eu and Gd of chlorides. CONCLUSIONS: Analysis of compounds inside correlative specimens by means of CLSM, SIMS, and EELS microscopes provided complementary results.

Recall of diet during a past pregnancy.

The authors conducted a study of women's ability to recall diet during a past pregnancy. For a prospective study, women completed self-administered food frequency questionnaires (FFQs) before and during pregnancy (1989-1992). These women, mostly White and well-educated, were contacted 3-7 years later (1996-1997) for a retrospective dietary assessment performed by either telephone interview (n = 154) or self-administered FFQ (n = 115). Energy-adjusted Pearson correlations ranged from 0.10 to 0.49 for the telephone interview group and from 0.02 to 0.67 for the self-administered questionnaire group. When participants' intakes were ranked, quintile agreement (within one quintile) between original diet and recalled diet ranged from 60% to 69% in the telephone interview group and from 69% to 79% in the self-administered questionnaire group. Correlations and percentages of agreement were higher among women who used the same questionnaire for both dietary assessments than among those who used different questionnaires. These results suggest that diet during pregnancy is recalled with similar accuracy as or perhaps slightly lower accuracy than adult diet generally. This may reflect, in part, the influence of current (nonpregnancy) diet on recall of past (pregnancy) diet. While the results of this study may not be generalizable to those obtained from other populations, to the authors' knowledge it is the first study of recall of diet during pregnancy.

Pulmonary adenocarcinoma simulating malignant mesothelioma.

Adenocarcinoma of the lung with pleural involvement frequently resembles pleural epithelioid mesothelioma clinically as well as macro- and microscopically. Special stains, immunohistochemical studies, and electron microscopic studies are needed to differentiate these 2 tumors. We report a case of pleural involvement by adenocarcinoma, mimicking in the hematoxylin-eosin stain an epithelioid mesothelioma, correctly identified only after immunohistochemical and electron microscopic examinations.

Liver pathology in children with AIDS: a comparison between the South American and North American population.

Liver tissue from autopsies of twenty-nine cases of children with AIDS were collected from three major South America (S.4) pediatric hospitals. The hepatopathologic findings were classified in the same fashion as in a series of sixty-one children with AIDS from North America (NA): inflammation, non-specific, lymphoproliferative disorders, and giant cell transformation. By comparing both groups. we noted that the SA children were Younger at time of death consistent with a more rapid progression of the disease. Opportunistic infections varied with a higher prevalence of Cytomegalovirus (CMV) infection in SA children. The histopathologic features of CMV in the liter of SA children were associated with a conspicuous inflammation absent in the NA group. Finally, different non-specific hepatic changes were found in SA children, including one case of peliosis hepatis.

SIMS evidence that carbimazole enhances spatial heterogeneity of thyroid iodine storage and targeting in a woman with Graves' disease.

Antithyroid drugs (ATD) are known to reduce 131I efficacy in thyrotoxicosis, though the underlying mechanism remains misunderstood. To study the impact of long term administration of carbimazole on both iodine stores (127I, secondary ion mass spectrometry microscopy) and targeting (125I, radioautography) at the intraglandular level in a woman who underwent surgery for Graves' disease. 125I distribution was dramatically heterogenous and large areas of the sample appeared poorly or no stained at all. This may correspond to flat follicles, hypofunctioning or ATD blocked ones and to the various histological changes related to the thyroiditis. SIMS counting showed huge variations of the interfollicular iodine stores (0 to 1.18 microg/mg) and lower mean values than those observed in nodular goiters. SIMS imaging depicted iodine free areas and others with preserved thyroglobulin synthesis, as assessed via 32S- mapping, but low to undetectable 127I, suggesting focal organification defects. Since ATD reduce iodine storage and uptake capabilities and enhance the iodine heterogeneity of interfollicular targeting, a related enhancement of the spatial 131I dose distribution is unavoidable. ATD may reduce 131I efficacy by variably reducing the number of follicles which can be actually or significantly targeted, e.g. irradiated (antirecruitement effect).

Origin of cardiac mucosa: ontogenic consideration.

The origin and histology of the cardiac mucosa remains controversial. The classical concept that the cardiac mucosa is of gastric origin has been challenged by those who advocate that the cardiac mucosa results from a metaplastic esophageal process. Some regard cardiac mucosa as consisting solely of pure mucous glands, whereas others accept the presence of isolated parietal cells within the mucous gland (mixed glands). In this study, we have clarified the presence and site of origin of the cardiac mucosa and its histological composition. To do so we studied the microscopic characteristics of the gastric side of the squamous-columnar junction (SCJ) of 77 autopsied fetuses of different gestational ages (prenatal group) and of infants, young children, and adolescents (postnatal group). We evaluated the presence or absence of a transitional zone, defined as the area between the squamous esophageal and oxyntic mucosa, the glandular composition of the transitional zone (i.e., pure mucous and mixed glands), and the presence or absence of inflammation. Our study revealed that a transitional zone with the microscopic characteristics of cardiac mucosa was universally present at the SCJ. The microscopic characteristics of this zone varied with age. Both pure mucous and mixed glands were observed. We conclude that the cardiac mucosa is partially if not entirely the result of normal embryonic gastric development. Both mucous and mixed glands constitute normal components of the cardiac mucosa.

Confocal image characterization of human papillomavirus DNA sequences revealed with Eu in HeLa cell nuclei stained with Hoechst 33342.

OBJECTIVE: To visualize and localize specific viral DNA sequences revealed with Eu by fluorescence in situ hybridization, confocal laser scanning microscopy (CLSM) and factor analysis of biomedical image sequences (FAMIS). STUDY DESIGN: Human papillomavirus DNA (HPV-DNA) was identified in HeLa cells with biotinylated DNA probes recognizing HPV-DNA types 16/18. DNA-DNA hybrids were revealed by a three-step immunohistochemical amplification procedure involving an antibiotin mouse monoclonal antibody, a biotinylated goat antimouse polyclonal antibody and streptavidin-Eu. Cell nuclei were counterstained with Hoechst 33342. Image sequences were obtained using a CLSM that made possible ultraviolet excitation. The location of fluorescent signals inside cellular preparations was determined by FAMIS and selection of filters at emission. Image sequences were summarized into a reduced number of images, or factor images, and curves, or factors. Factors estimate spectral or temporal patterns and depth emission profiles. Factor images correspond to spatial distributions of the different factors. RESULTS: We distinguished between Eu corresponding to HPV-DNA hybridization signals and nuclear staining by taking into account differences in their spectral and temporal patterns and (using their decay rates). CONCLUSION: FAMIS, together with CLSM and Eu, made possible the detection and characterization of viral papillomavirus DNA sequences in HeLa cells.

Confocal analysis of phosphatidylserine externalization with the use of biotinylated annexin V revealed with streptavidin-FITC, -europium, -phycoerythrin or -Texas Red in oxysterol-treated apoptotic cells.

OBJECTIVE: To analyze externalization of phosphatidylserine via annexin V on apoptotic cells by laser scanning confocal microscopy and factor analysis of biomedical image sequences (FAMIS). STUDY DESIGN: Streptavidin-fluorescein isothiocyanate (FITC), -europium (Eu), -phycoerythrin (PE) and -Texas Red (TR) were chosen to reveal the binding of biotinylated annexin V on apoptotic U937 human leukemic cells and ECV-304 human endothelial cells induced under treatment with 7-ketocholesterol or 7 beta-hydroxycholesterol. Excitation of each fluorochrome was obtained by selection of specific lines (351 + 364 nm, 488 nm) of the argon laser of a confocal microscope. Temporal and spectral series were performed to characterize each fluorochrome. FAMIS was applied to these series to estimate images corresponding to stains. RESULTS: Each fluorochrome was clearly distinguished, and images showed localization of phosphatidylserine, which was improved by image analysis. CONCLUSION: On apoptotic cells it is possible to analyze differences in the improved visualization of phosphatidylserine in series processed by FAMIS with the use of biotinylated annexin V revealed with streptavidin-FITC, -Eu, -PE or -TR.

The maturation of dendritic cells results in postintegration inhibition of HIV-1 replication.

Maturation of dendritic cells (DC) is known to result in decreased capacity to produce HIV due to postentry block of its replicative cycle. In this study, we compared the early phases of this cycle in immature DC (iDC) and mature DC (mDC) generated from monocytes cultured with GM-CSF and IL-4, trimeric CD40 ligand (DC(CD40LT)), or monocyte-conditioned medium (DC(MCM)) being added or not from day 5. Culture day 8 cells exposed to X4 HIV-1(LAI) or R5 HIV-1(Ba-L) were analyzed by semiquantitative R-U5 PCR, which detects total HIV DNA. CXC chemokine receptor 4(low) (CXCR4(low)) CCR5(+) iDC harbored similar viral DNA amounts when exposed to either strain. HIV-1(LAI) entered more efficiently into DC(CD40LT) or DC(MCM) with up-regulated CXCR4. CCR5(low) DC(CD40LT) still allowed entry of HIV-1(Ba-L), whereas CCR5(-) DC(MCM) displayed reduced permissivity to this virus. Comparing amounts of late (long terminal repeat (LTR)-gag PCR) and total (R-U5 PCR) viral DNA products showed that HIV-1(Ba-L) reverse transcription was more efficient than that of HIV-1(LAI), but was not affected by DC maturation. Southern blot detection of linear, circular, and integrated HIV DNA showed that maturation affected neither HIV-1 nuclear import nor integration. When assessing virus transcription by exposing iDC to pNL4-3.GFP or pNL4-3.Luc viruses pseudotyped with the G protein of vesicular stomatitis virus (VSV-G), followed by culture with or without CD40LT or MCM, GFP and luciferase activities decreased by 60-75% in mDC vs iDC. Thus, reduced HIV replication in mDC is primarily due to a postintegration block occurring mainly at the transcriptional level. We could not relate this block to altered expression and nuclear localization of NF-kappa B proteins and SP1 and SP3 transcription factors.

[Recessive type of Freeman-Sheldon syndrome - report of two affected siblings] / Forma recessiva da síndrome de Freeman-Sheldon - relato de dois irmãos afetados.

OBJECTIVE: To share knowledge and information about the peculiarities of the Freeman-Sheldon syndrome, especially concerning the high risk of recurrence of its recessive type in siblings, and to stress the importance of genetic counseling for families after the birth of an affected child. DESCRIPTION: The authors describe and comment two pediatric cases of the Freeman-Sheldon syndrome in siblings born to healthy parents. These two cases present significant peculiarities that contradict the findings of the medical literature, obtained through bibliographic research about the subject. The cases described here corroborate the existence of a recessive type of the Freeman-Sheldon syndrome. In spite of the fact that some authors suggest a high frequency of severe neurological impairment in this type of syndrome, the two cases we analyzed did not show any apparent manifestation of such sequelae. COMMENTS: The Freeman-Sheldon syndrome is heterogeneous not only in its clinical presentation but also in its genetic transmission. It is very important to be informed about the existence of more than one form of hereditary transmission of this syndrome, since genetic counseling should take into consideration all possibilities. In these cases, the use of empiric risks of recurrence would be justified.

Characterization of dendritic cell differentiation pathways from cord blood CD34(+)CD7(+)CD45RA(+) hematopoietic progenitor cells.

To better characterize human dendritic cells (DCs) that originate from lymphoid progenitors, the authors examined the DC differentiation pathways from a novel CD7(+)CD45RA(+) progenitor population found among cord blood CD34(+) cells. Unlike CD7(-)CD45RA(+) and CD7(+)CD45RA(-) progenitors, this population displayed high natural killer (NK) cell differentiation capacity when cultured with stem cell factor (SCF), interleukin (IL)-2, IL-7, and IL-15, attesting to its lymphoid potential. In cultures with SCF, Flt3 ligand (FL), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor (TNF)-alpha (standard condition), CD7(+)CD45RA(+) progenitors expanded less (37- vs 155-fold) but yielded 2-fold higher CD1a(+) DC percentages than CD7(-)CD45RA(+) or CD7(+)CD45RA(-) progenitors. As reported for CD34(+)CD1a(-) thymocytes, cloning experiments demonstrated that CD7(+)CD45RA(+) cells comprised bipotent NK/DC progenitors. DCs differentiated from CD7(-)CD45RA(+) and CD7(+)CD45RA(+) progenitors differed as to E-cadherin CD123, CD116, and CD127 expression, but none of these was really discriminant. Only CD7(+)CD45RA(+) or thymic progenitors differentiated into Lag(+)S100(+) Langerhans cells in the absence of exogenous transforming growth factor (TGF)-beta 1. Analysis of the DC differentiation pathways showed that CD7(+)CD45RA(+) progenitors generated CD1a(+)CD14(-) precursors that were macrophage-colony stimulating factor (M-CSF) resistant and CD1a(-)CD14(+) precursors that readily differentiated into DCs under the standard condition. Accordingly, CD7(+)CD45RA(+) progenitor-derived mature DCs produced 2- to 4-fold more IL-6, IL-12, and TNF-alpha on CD40 ligation and elicited 3- to 6-fold higher allogeneic T-lymphocyte reactivity than CD7(-)CD45RA(+) progenitor-derived DCs. Altogether, these findings provide evidence that the DCs that differentiate from cord blood CD34(+)CD7(+)CD45RA(+) progenitors represent an original population for their developmental pathways and function. (Blood. 2000;96:3748-3756)

Emergence of a new Vibrio parahaemolyticus serotype in raw oysters: A prevention quandary.

CONTEXT: In May and June 1998, reported Vibrio parahaemolyticus infections increased sharply in Texas. OBJECTIVE: To determine factors that contributed to the increase in V parahaemolyticus infections. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional survey of persons reporting gastroenteritis after eating seafood in Texas; survey of environmental conditions in Galveston Bay. MAIN OUTCOME MEASURES: Traceback of oysters, water quality measures in harvest areas, presence of V parahaemolyticus in stool cultures; comparison of median values for environmental conditions before and during the outbreak compared with during the previous 5 years. RESULTS: Between May 31 and July 10, 1998, 416 persons in 13 states reported having gastroenteritis after eating oysters harvested from Galveston Bay. All 28 available stool specimens from affected persons yielded V parahaemolyticus serotype O3:K6 isolates. Oyster beds met current bacteriologic standards during harvest and fecal coliform counts in water samples were within acceptable limits. Median water temperature and salinity during May and June 1998 were 30.0 degrees C and 29.6 parts per thousand (ppt) compared with 28.9 degrees C and 15.6 ppt for the previous 5 years (P<.001). CONCLUSIONS: This is the first reported outbreak of V parahaemolyticus serotype O3:K6 infection in the United States. The emergence of a virulent serotype and elevated seawater temperatures and salinity levels may have contributed to this large multistate outbreak of V parahaemolyticus. Bacteriologic monitoring at harvest sites did not prevent this outbreak, suggesting that current policy and regulations regarding the safety of raw oysters require reevaluation. Consumers and physicians should understand that raw or undercooked oysters can cause illness even if harvested from monitored beds. In patients who develop acute gastroenteritis within 4 days of consuming raw or undercooked oysters, a stool specimen should be tested for Vibrio species using specific media. JAMA. 2000;284:1541-1545.

Role of cationic amino acids in the Na+/dicarboxylate co-transporter NaDC-1.

The role of cationic amino acids in the Na(+)/dicarboxylate co-transporter NaDC-1 was investigated by site-directed mutagenesis and subsequent expression of mutant transporters in Xenopus oocytes. Of the ten residues chosen for mutagenesis, eight (Lys-34, Lys-107, Arg-108, Lys-333, Lys-390, Arg-368, Lys-414 and Arg-541) were found to be non-essential for function or targeting. Only two conserved residues, Lys-84 (at the cytoplasmic end of helix 3) and Arg-349 (at the extracellular end of helix 7), were found to be important for transport. Both mutant transporters were expressed at the plasma membrane. The mutation of Lys-84 to Ala resulted in an increased K(m) for succinate of 1.8 mM, compared with 0.3 mM in the wild-type NaDC-1. The R349A mutant had Na(+) and citrate kinetics that were similar to those of the wild type. However, succinate handling in the R349A mutant was altered, with evidence of inhibition at high succinate concentrations. In conclusion, charge neutralization of Lys-84 and Arg-349 in NaDC-1 affects succinate handling, suggesting that these residues might have roles in substrate binding.

Inflammatory polyps after necrotizing enterocolitis.

Necrotizing enterocolitis (NEC) is the most common gastrointestinal emergency in the neonatal period. NEC causes ulceration of the intestinal mucosa and may lead to perforation or a stricture. To the best of the authors' knowledge intestinal inflammatory polyps after NEC have not been described previously. The authors report on a 17-week-old boy with pseudopolyps at the site of a colonic stricture after NEC.

Prevalence and pathogenesis of pancreatic acinar tissue at the gastroesophageal junction in children and young adults.

BACKGROUND: Pancreatic acinar tissue (PAT) at the gastroesophageal junction (GEJ) has been reported in 3% of adults with Barrett esophagus (BE) and in 24% of healthy subjects. The pathogenesis of this ectopic tissue is controversial. Both an acquired metaplastic process in the setting of BE and a congenital abnormality have been suggested in adults. OBJECTIVE: To clarify the origin of PAT at the GEJ. METHODS: We reviewed material obtained from the GEJ in 69 children and young adults. Each specimen was evaluated by 3 levels stained with hematoxylin-eosin for the presence of PAT, BE, esophagitis, and gastritis. Selected cases were also examined with immunohistochemical stains for lipase, trypsin, and amylase. RESULTS: In 16% of the study population, PAT was present at the GEJ and was not associated with BE. The prevalence of esophagitis and/or gastritis did not vary significantly between patients with and without PAT. CONCLUSIONS: Our data suggest that PAT at the GEJ develops independently of inflammation and is, therefore, likely to be congenital.