Developmental aspects of children's behavior and safety while cycling

OBJECTIVE: To examine children's competence while cycling, as demonstrated in mistakes in performance and failure to comply with safety rules. METHODS: Children in three age groups (8, 10, and 12 years) participated in a realistic yet simulated traffic environment. RESULTS: The boys' cycling speed increased steadily with age, while that of the girls increased from 8 to 10 but decreased at age 12. Most children had adequate motor control by age 10, and the youngest compensated for their less developed skills by cycling slowly and braking early at junctions. Serious mistakes, often related to the children's age and gender, consisted of the children failing to stop at signals or stopping too late, especially at short stopping range. CONCLUSIONS: There are considerable individual differences in children's cycling competence that are related to biological factors, such as age and gender, and psychological factors, such as rule compliance and choice of cycling speed.     

Metameriest?rungen und ihre Konsequenzen im S?ugetierexperiment

Zusammenfassung Störungen der Segmentierung werden bei der Hausmaus durch die Erbfaktoren Crooked tail und Rib fusions wie auch durch weitere Gene hervorgerufen. Eine Phänokopie der Mutation Rib fusions durch Sulfonylharnstoff (Rastinon) wird beschrieben. Als Ursache der beobachteten Wirbel-Rippenmißildungen ist eine Störung der Zellaggregation zu betrachten, die sich durch alle Entwicklungsphasen bis zur knöchernen Fehlbildung auswirkt.Die empfindliche Phase ist die Heraussonderung der Ursegmente aus dem undifferenzierten Mesoblasten. Ihre Beeinflussung, speziell durch hypoglykämische Agentien, wird nach Ort und Zeit analysiert und die Entwicklung der entstehenden Mißbildung untersucht.Es wird die Hypothese aufgestellt, daß in dieser Phase ein erhöhter Energiebedarf besteht, der durch eine Störung der Oxydationsprozesse blockiert werden kann.Ausgeführt mit Hilfe der Stiftung für wissenschaftliche Forschung an der Universität Zürich.     

Antibody-bearing liposomes as multicolor immunofluorescence markers for flow cytometry and imaging

Loposomes covalently coupled to monoclonal antibodies retain the specificity of the antibody and bind only to cells bearing the appropriate determinant. As opposed to directly labeled antibodies which generally have fluorochrome to protein ratio of between 2–5, the entrapped space inside liposome can contain several hundred to several thousand molecules of fluorochromes in a space chemically isolated from the outside environment, thus providing the potential for an amplified fluorescence signal. We have prepared small unilamellar liposomes containing the soluble fluorochromes carboxyfluorescein (CF), which fluoresces in the green and sulforhodamine (SR), which fluoresces in the red, and covalently coupled a series of monoclonal antibodies using a heterobifunctional reagent. We were able to detect, on an Epics 753 flow cytometer equipped with an argon ion and a dye laser and by fluorescence microscopy, both single and double labeled mouse spleen lymphocyte subsets, fibroblast L cells and Raji cells. Complete color separation was obtained with CF-labeled cells being detected only by the green photomultiplier and SR-labeled cells by the red photomultiplier. Cells labeled with both were detected by both photomultipliers. Liposomes bearing anti-Ia antibodies bound only to B lymphocytes whereas those with anti-H-2K antibody bound both to T and B lymphocytes. In another system, single and dual color immunofluorescence made possible the simultaneous detection of HLA and H-2K molecules on transfected murine fibroblast L cells. The signal-to-noise ratio was more favorable for the liposome-labeled reagents than reagents labeled with fluorescein isothiocyanate. Cells labeled with antibody-bearing liposomes could be fixed with paraformaldehyde or glutaraldehyde without adversely affecting the original staining patterns. Apart from the two fluorochromes described above, other markers of choice could be encapsulated without any adverse effect on the antibody-liposome coupling procedure or on the specificity of the conjugated antibody. Since the fluorochrome is not directly coupled to the protein, there is no requirement for protein conjugation sites in order for it be usefully encapsulated inside liposomes. Therefore, this system provides new opportunities to exploit different, as yet untapped fluorochromes for use in flow cytometry and imaging.     

Über die Erkennung von Keimzentrumszellen im Lymphknotenausstrich

Zusammenfassung Im Lymphknotenausstrich kommen basophile Zellen vor, die weitgehend spezifisch für die Keimzentren der Sekundärknötchen sind und als Germinoblasten bezeichnet werden. Sie sind bei follikulärer lymphatischer Hyperplasie und bei M. Brill-Symmerserheblich vermehrt. Ihre Morphologie wird im einzelnen beschrieben und durch Abbildungen belegt. Eine Unterscheidung von den basophilen Stammzellen, den großen lymphatischen Reticulumzellen der Literatur, ist möglich und nötig, da diese Zellen in Sekundärknötchen und Pulpa gleichermaßen vorkommen.     

Composite Large-Cell Neuroendocrine Carcinoma and Surface Epithelial-Stromal Neoplasm of the Ovary

The clinicopathologic features of two cases of composite large-cell neuroendocrine carcinoma and surface epithelial-stromal neoplasm of the ovary are reported and those of eight previously published cases reviewed. The patients ranged in age from 22 to 77 years (mean, 56 years). The surface epithelial-stromal neoplasm was an endometrioid adenocarcinoma in one case, a mucinous cystadenoma in one case, and a mucinous adenocarcinoma in eight cases. The large-cell neuroendocrine carcinoma in these tumors may represent dedifferentiation of the neuroendocrine cells present in the surface epithelial-stromal tumor. This composite tumor type is highly aggressive. Of eight patients with follow-up information, all had died of disseminated tumor; six within 10 months, and two in 19 months and 3 years, respectively, after diagnosis. Only the neuroendocrine carcinoma component was found in the metastatic sites. Int J Surg Pathol 8(2):169-174, 2000     

c-Fos-dependent induction of the small ras-related GTPase Rab11a in skin carcinogenesis

Malignant transformation of mouse skin by tumor promoters and chemical carcinogens, such as the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), is a multistage process leading to the formation of squamous cell carcinomas. It has been shown that mice lacking the AP-1 family member c-Fos exhibit an impaired transition from benign to malignant skin tumors. Here, we demonstrate enhanced expression of the small Ras-related GTPase Rab11a after short-term TPA treatment of mouse back skin. Expression of Rab11a in vivo and in vitro critically depended on c-Fos, because TPA application to the back skin of c-Fos-deficient mice and to mouse embryonic fibroblasts did not induce Rab11a mRNA or protein expression. Moreover, dexamethasone, which is a potent inhibitor of AP-1-mediated transactivation that exhibits anti-inflammatory and anti-tumor promoting activities, inhibited TPA-induced expression of Rab11a. Within the Rab11a gene promoter, we identified a functional AP-1 binding element that exhibited elevated c-Fos binding activity after TPA treatment of keratinocytes. Enhanced expression was not restricted to chemically induced mouse skin tumors but was also found in tumor specimens derived from patients with epithelial skin tumors. These data identify Rab11a as a novel, tumor-associated c-Fos/AP-1 target and may point to an as yet unrecognized function of Rab11a in the development of skin cancer.     

Increased venous proinflammatory gene expression and intimal hyperplasia in an aorto-caval fistula model in the rat

We hypothesized that the venous limb of an arteriovenous (AV) fistula would evince up-regulation of genes relevant to vascular remodeling along with neointimal hyperplasia and relevant histological changes. Using the aorto-caval model of an AV fistula model in the rat, we demonstrate marked up-regulation in such proinflammatory genes as monocyte chemoattractant protein-1, plasminogen activator inhibitor-1, and endothelin-1, 2 weeks after the creation of the fistula. Neointimal hyperplasia occurred in variable degrees by 5 weeks after establishing the fistula, and by 16 weeks, such neointimal hyperplasia was progressive and pronounced; at this time point, abundant extracellular matrix was also observed. Smooth muscle cells were present in the hyperplastic neointima as evidenced by staining for alpha-smooth muscle actin; ultrastructurally, smooth muscle cells with a synthetic as well as a contractile phenotype were readily observed. Accumulation of extracellular matrix in the model at 16 weeks was accompanied by increased expression of transforming growth factor-beta1 mRNA, the latter finding contrasting with the suppression of transforming growth factor-beta1 mRNA observed in this model at 2 weeks. In summary, we describe marked up-regulation in proinflammatory genes and progressive neointimal formation in the venous vasculature in an AV fistula model in the rat. We suggest that such alteration in gene expression and histological injury, in conjunction with the relative simplicity of this model, offer a new approach in the study of such timely biological and clinically relevant phenomena as differential gene expression in response to hemodynamic forces, processes involved in vascular remodeling, mechanisms of injury in venous bypass grafts, and mechanisms of dysfunction of AV fistulae used in hemodialysis.     

Detection of Campylobacter spp. in chicken fecal samples by real-time PCR

A real-time PCR assay for detecting thermophilic Campylobacter spp. directly in chicken feces has been developed. DNA was isolated from fecal material by using magnetic beads followed by PCR with a prealiquoted PCR mixture, which had been stored at -18 degrees C. Campylobacter could be detected in less than 4 h, with a detection limit of 100 to 150 CFU/ml, in a fecal suspension. A bacterial internal control was added before DNA extraction to control both DNA isolation and the presence of PCR inhibitors in the samples. The assay was performed on 111 swab samples from a Danish surveillance program and compared to conventional culturing using selective enrichment. There was no statistically significant difference in performance between real-time PCR and culture by selective enrichment, and the diagnostic specificity was 0.96 with an agreement of 0.92. Therefore, the assay should be useful for screening poultry flocks for the presence of Campylobacter.