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1.
A simple modification of nuclear staining after acid hydrolysis has been made which provides easy identification of quail nuclear markings in a chick-quail chimera. This method also improves the histologic detail normally seen with hematoxylin and eosin when compared to the more commonly used Feulgen reaction. Embryonic tissues can be fixed in Zenker's or Helly's solution and the sections obtained are hydrolyzed in acid (3.5 N HCl at 37 C for 40-50 min). After acid hydrolysis the sections are stained with hematoxylin and eosin rather than Schiff reagent and fast green. The interphase nuclei of chick cells show homogeneous or mottled purplish blue staining, while quail nuclei contain a dark blue spot. This staining corresponds to the reddish purple staining of the quail's heterochromatin seen adjacent to the nucleolus in the standard Feulgen stain. This new technique facilitates identification of quail cell types in the chick host and provides superior histology of the chick tissues by demonstrating cytoplasmic detail. 相似文献
2.
C E Bueso-Ramos R M Donahoe J K Nicholson J J Madden A Falek 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(5):1414-1420
Incubation of human T lymphocytes with saturating concentrations of combinations of certain anti-CD2 and -CD4 mAb results in reciprocal down-regulation of the cell surface density expression of the respective CD molecules. Such reciprocal down-regulation occurs at 0 degrees C in the presence of sodium azide and appears selective for CD2 and CD4 molecules because mAb identifying various other CD T cell surface molecules (anti-Leu2a, -OK-CLL, -W6/32, -beta 2-microglobulin, -4B4) do not modulate CD2 or CD4 R density, and because anti-CD2 mAb (anti-OKT11 and -D66 clone-1) do not alter CD8 R density (anti-OKT8, -Leu2a) and vice versa. Down-regulation of CD2 by mAb specific to CD4 is epitope-specific but does not vary on the basis of the antibody isotype used. The anti-CD4 mAb, Leu3a, was the strongest CD2 down-regulator examined followed by OKT4F. mAb specific to other CD4 epitopes (B, C, D, and E) caused only slight down-regulation of CD2 expression whereas anti-OKT4 and -OKT4A mAb had no significant regulatory effect. Also, mAb specific to the 9.6 (anti-OKT11) and D66 (anti-D66 clone 1) epitopes of the CD2 molecule down-regulated CD4 density detectable with Leu3a, OKT4, and OKT4A anti-CD4 mAb. Down-regulation of CD2 by anti-CD4 mAb also occurred with the transformed T cell line, KE-37, which demonstrates that such effects can occur without mononuclear phagocytic accessory cells. From these data it can be concluded that important T cell immunoregulatory signals may be transmitted intramembranally between CD2 and CD4 glycoproteins. 相似文献
3.
James Epstein Edward J. Desjardins Peter L. Hudson Patricia K. Donahoe 《In vitro cellular & developmental biology. Plant》1989,25(2):213-216
Summary Stainless steel mesh supported the high density growth of anchorage dependent CHO fibroblasts without the use of a special
culture system. CHO cells, designated B-9, containing an amplified genomic construct of the human gene for Mullerian Inhibiting
Substance (MIS), grew to a high confluent density on stainless steel meshwork while producing substantial amounts of human
recombinant MIS over a long period of time. The mesh could be easily coated with various extracellular matrix proteins, such
as Laminin, Fibronectin, Collagen or Matrigel, which permitted the testing of the effects of surface modifications on cell
yield and recombinant protein production. Since the amount of medium per surface area required for optimal cell growth is
lower than for some large volume cell culture methods, media costs can be reduced using mesh. In addition, no special cell
culture equipment or complex manipulations are required. Thus, the use of meshwork for anchorage-dependent cells can increase
the efficiency of growth and decrease the cost of recombinant protein production.
This work is supported by NIH grant CA 17393 and American Cancer Society grant PDT 221A to P. K. D. and NIH grant EY 06535
to J. E.
Editor's Statement This approach to large scale, high density cultivation of cells, one of several which are based on increasing
surface area of the cultures, allows the production of large amounts of recombinant product within a research laboratory with
modest bulk culture capability. 相似文献
4.
Population genetics and phylogenetics of DNA sequence variation at multiple loci within the Drosophila melanogaster species complex 总被引:14,自引:1,他引:13
Two regions of the genome, a 1-kbp portion of the zeste locus and a 1.1-
kbp portion of the yolk protein 2 locus, were sequenced in six individuals
from each of four species: Drosophila melanogaster, D. simulans, D.
mauritiana, and D. sechellia. The species and strains were the same as
those of a previous study of a 1.9-kbp region of the period locus. No
evidence was found for recent balancing or directional selection or for the
accumulation of selected differences between species. Yolk protein 2 has a
high level of amino acid replacement variation and a low level of
synonymous variation, while zeste has the opposite pattern. This contrast
is consistent with information on gene function and patterns of codon bias.
Polymorphism levels are consistent with a ranking of effective population
sizes, from low to high, in the following order: D. sechellia, D.
melanogaster, D.mauritiana, and D. simulans. The apparent species
relationships are very similar to those suggested by the period locus
study. In particular, D. simulans appears to be a large population that is
still segregating variation that arose before the separation of D.
mauritiana and D. sechellia. It is estimated that the separation of
ancestral D. melanogaster from the other species occurred 2.5-3.4 Mya. The
separations of D. sechellia and D. mauritiana from ancestral D. simulans
appear to have occurred 0.58- 0.86 Mya, with D. mauritiana having diverged
from ancestral D. simulans 0.1 Myr more recently than D. sechellia.
相似文献
5.
6.
A 25% weight loss was induced in adult Fisher 344 rats by nutritional deprivation. Subsequently, normal feeding was resumed. Refed animals were divided into three groups and received recombinant human growth hormone (rhGH) injections during 5 wk of refeeding, saline injections during 5 wk of refeeding, or 9 wk of refeeding without injections. The effects of nutritional deprivation and the various refeeding protocols on the cross-sectional areas (CSA) of each of the four types of myofibers [typed immunohistochemically with antibodies against four myosin heavy chain (MHC) isoforms known to be present in the rat diaphragm] were determined. Malnutrition decreased the CSA of myofibers containing MHC2X, MHC2B, and MHC2A (i.e., fast myofibers), with the greatest effect on muscle mass being due to the atrophy of fibers containing MHC2X. Fibers containing MHC beta/slow failed to undergo malnutrition-induced atrophy. Whereas refeeding for 5 wk in the absence of rhGH allowed the recovery of CSA of fibers containing MHC2A, fibers containing MHC2B and MHC2X remained smaller than fibers of similar type in control animals. In contrast, 5 wk of refeeding supplemented with rhGH returned all fiber CSAs to control values. Even when refeeding alone was extended to 9 wk to allow for weight stabilization, the CSA of the fibers containing MHC2B and MHC2X remained smaller than similar fibers in control muscle. Serum insulin-like growth factor, a marker of malnutrition (R. Reeves and J. Elders, J. Nutr. 109: 613-620, 1979), was significantly decreased after nutritional deprivation and returned to normal after 5 wk of refeeding and GH supplementation. 相似文献
7.
8.
9.
Ethan L. Sanford Kwong W. Choy Patricia K. Donahoe Adam A. Tracy Regis Hila Maria Loscertales Mauro Longoni 《PloS one》2016,11(2)
Congenital diaphragmatic hernia is associated with pulmonary hypoplasia and respiratory distress, which result in high mortality and morbidity. Although several transgenic mouse models of lung hypoplasia exist, the role of miRNAs in this phenotype is incompletely characterized. In this study, we assessed microRNA expression levels during the pseudoglandular to canalicular phase transition of normal human fetal lung development. At this critical time, when the distal respiratory portion of the airways begins to form, microarray analysis showed that the most significantly differentially expressed miRNA was miR-449a. Prediction algorithms determined that N-myc is a target of miR-449a and identified the likely miR-449a:N-myc binding sites, confirmed by luciferase assays and targeted mutagenesis. Functional ex vivo knock-down in organ cultures of murine embryonic lungs, as well as in ovo overexpression in avian embryonic lungs, suggested a role for miR-449a in distal epithelial proliferation. Finally, miR-449a expression was found to be abnormal in rare pulmonary specimens of human fetuses with Congenital Diaphragmatic Hernia in the pseudoglandular or canalicular phase. This study confirms the conserved role of miR-449a for proper pulmonary organogenesis, supporting the delicate balance between expansion of progenitor cells and their terminal differentiation, and proposes the potential involvement of this miRNA in human pulmonary hypoplasia. 相似文献
10.
C García-Vielma MI Dávila-Rodríguez F Hernández-Garza RM Cerda-Flores 《Biotechnic & histochemistry》2016,91(2):102-107
We performed a hospital-based, unmatched case-control study to investigate the association between progressive stages of cervical neoplasia and digital analysis of cell proliferation by silver stained nucleolus organizer region associated proteins (AgNORs). We measured cell proliferation levels in the cervical epithelial cells of 10 women with low grade squamous intraepithelial lesions (LG-SIL), eight with high grade squamous intraepithelial lesions (HG-SIL), 11 with cervical cancer (CC) and eight with no cervical lesions (controls) using the AgNORs technique. Cell proliferation was measured by digital image analysis (DIA). DIA revealed increased total areas of AgNORs in HG-SIL and CC compared to LG-SIL and control patients. AgNORs with a kidney or cluster shape exhibited greater areas than those with a spherical or long shape. We propose a cut-off of 118 pixels to differentiate benign (control and LG-SIL) from malignant (HG-SIL and CC) lesions. DIA of AgNORs is a simple and inexpensive method for studying proliferation. The increased total area of AgNORs in malignant lesions provides information regarding cell behavior and may be related to cervical carcinogenesis; however, further validation studies are required to establish its usefulness in cytological analysis. 相似文献