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At least 685 records · Page 38Linked to original sources
PubMed2002

Differential expression of retinoic acid-synthesizing (RALDH) enzymes during fetal development and organ differentiation in the mouse.

Three retinaldehyde dehydrogenases (RALDH1, RALDH2 and RALDH3), which catalyze the oxidation of retinaldehyde into retinoic acid, have been shown to be differentially expressed during early embryogenesis. Here, we report their differential expression patterns throughout later mouse organogenesis. Raldh1 is prominently expressed in developing lung (notably in bronchial and tracheal epithelia), and shows stage-specific expression in stomach and intestine epithelial and mesenchymal layers. Raldh3 expression is specific to the differentiating intestinal lamina propria. Raldh2 is expressed throughout the kidney nephrogenic zone, whereas Raldh1 and Raldh3 are mostly expressed in collecting duct epithelia. Raldh3 expression is more restricted than that of Raldh1 in the urogenital tract and sex gland epithelia, whereas Raldh2 expression is mesenchymal. Raldh1 is coexpressed with Raldh2 in the early heart epicardium, and is later specifically expressed in developing heart valves. All three genes exhibit distinct expression patterns in respiratory and olfactory epithelia and/or mesenchymes, and in developing teeth. Only Raldh1 expression is seen after birth in specific brain structures. These data indicate a requirement for regulated RA synthesis in various differentiating organs.

Abdomen↗
PubMed1999

Differential localization of two histidine kinases controlling bacterial cell differentiation.

The bacterium C. crescentus coordinates cellular differentiation and cell cycle progression via a network of signal transduction proteins. Here, we demonstrate that the antagonistic DivJ and PleC histidine kinases that regulate polar differentiation are differentially localized as a function of the cell cycle. The DivJ kinase localizes to the stalked pole in response to a signal at the G1-to-S transition, while the PleC kinase is localized to the flagellar pole in swarmer and predivisional cells but is dispersed throughout the cell in the stalked cell. PleC, which is required for DivJ localization, may provide the cue at the G1-to-S transition that directs the polar positioning of DivJ. The dynamic positioning of signal transduction proteins may contribute to the regulation of polar differentiation at specific times during the bacterial cell cycle.

Bacterial Proteins↗
PubMed1996

Differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts.

Scirrhous gastric cancer cells proliferate rapidly with fibrosis, when the cancer cells invade into the submucosa of the stomach. To investigate the mechanisms responsible for the rapid proliferation, the growth interaction between gastric cancer cells and fibroblasts was examined. Human gastric cancer cell lines established from scirrhous carcinoma or well-differentiated adenocarcinoma were used. Human fibroblast cell lines were obtained from various organs. The growth interaction between gastric cancer cells and fibroblasts was examined by calculating the number of cancer cells or by measuring [3H]thymidine incorporation of cancer cells. Gastric fibroblasts specifically stimulated the growth of scirrhous gastric cancer cells, but not that of well-differentiated adenocarcinoma cells. The growth factor(s) produced from gastric fibroblasts were then partially purified and characterised. The growth-promoting factor(s) had apparent molecular weights of 10000 dalton and was sensitive both to heat and proteinase treatment. No inhibition for the factor(s) was achieved with defined anti-growth factor antibodies. In this study, differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts were shown. Rapid proliferation of scirrhous gastric carcinoma should be partly controlled by orthotopic fibroblasts. The growth factor(s) from gastric fibroblasts, which was distinct from various defined growth factors such as epidermal growth factor (EGF), basic fibroblast growth factor (b-FGF), transforming growth factor-alpha (TGF-alpha), keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF), insulin-like growth factor I (IGF-I), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF) and transforming growth factor beta 1 (TGF-beta 1) may play an important role in the progression of scirrhous gastric cancer cells.

Adenocarcinoma, Scirrhous↗
PubMed2006

Item and scale differential functioning of the Mini-Mental State Exam assessed using the Differential Item and Test Functioning (DFIT) Framework.

OBJECTIVES: To illustrate the application of the Differential Item and Test Functioning (DFIT) method using English and Spanish versions of the Mini-Mental State Examination (MMSE). SUBJECTS: Study participants were 65 years of age or older and lived in North Manhattan, New York. Of the 1578 study participants who were administered the MMSE 665 completed it in Spanish. MEASURES: : The MMSE contains 20 items that measure the degree of cognitive impairment in the areas of orientation, attention and calculation, registration, recall and language, as well as the ability to follow verbal and written commands. RESEARCH DESIGN: After assessing the dimensionality of the MMSE scale, item response theory person and item parameters were estimated separately for the English and Spanish sample using Samejima's 2-parameter graded response model. Then the DFIT framework was used to assess differential item functioning (DIF) and differential test functioning (DTF). RESULTS: Nine items were found to show DIF; these were items that ask the respondent to name the correct season, day of the month, city, state, and 2 nearby streets, recall 3 objects, repeat the phrase no ifs, no ands, no buts, follow the command, "close your eyes," and the command, "take the paper in your right hand, fold the paper in half with both hands, and put the paper down in your lap." At the scale level, however, the MMSE did not show differential functioning. CONCLUSIONS: Respondents to the English and Spanish versions of the MMSE are comparable on the basis of scale scores. However, assessments based on individual MMSE items may be misleading.

Aged↗
PubMed1994

Immunohistochemical detection of p53 in differentiated, poorly differentiated and undifferentiated carcinomas of the thyroid.

In an attempt to find whether or not p53 immunoreactivity in the thyroid gland is restricted to undifferentiated carcinomas and to evaluate the putative prognostic usefulness of its detection, we investigated p53 immunoreactivity in a series of 14 benign thyroid lesions and 65 thyroid carcinomas (12 papillary; six minimally invasive follicular; four widely invasive follicular; 31 poorly differentiated and 12 undifferentiated tumours). Unequivocal nuclear immunostaining for p53 was observed in two widely invasive follicular carcinoma (20.0%), five poorly differentiated carcinomas (16.1%) and in 10 undifferentiated carcinomas (83.3%). The percentage of immunoreactive cells was much smaller in the former groups than in undifferentiated carcinomas. Despite a trend to a more aggressive behaviour of the p53 immunoreactive cases no significant differences in the outcome of patients with positive and negative tumours was found when the comparison was made within each category of carcinomas. We conclude that p53 immunoreactivity can be detected both in undifferentiated carcinomas and in some differentiated and poorly differentiated thyroid carcinomas. Larger series of cases are necessary to evaluate the prognostic usefulness of this finding.

Adenocarcinoma, Follicular↗
PubMed2006

The chabot emotional differentiation scale: a theoretically and psychometrically sound instrument for measuring Bowen's intrapsychic aspect of differentiation.

Bowen's theory (1978) of differentiation is the personality variable most critical to mature development and the attainment of psychological health. The study of psychological differentiation has been confounded by confusion regarding the constructs being studied and the measurement tools used to assess them. The purpose of this review is to introduce and demonstrate the utility and importance of the Chabot Emotional Differentiation Scale (CED; Chabot, 1993), a self-report instrument specifically designed to measure Bowen's intrapsychic aspect of differentiation, or an individual's ability to distinguish between emotional and intellectual functioning and utilize intellect in emotionally charged situations. Psychometric support for the CED, validation and cross-cultural studies to date, and implications for theory, research, and practice are presented.

Expressed Emotion↗
PubMed2004

Mycobacterium bovis BCG cell wall-specific differentially expressed genes identified by differential display and cDNA subtraction in human macrophages.

We have analyzed the gene expression profile of monocytes in response to a highly purified cell wall fraction of Mycobacterium bovis BCG, a clinically approved adjuvant known as BCG cell wall skeleton (BCG-CWS). It is composed of mycolic acid, arabinogalactan, and peptidoglycan and confers Toll-like receptor 2 (TLR2)- and TLR4-dependent signaling that induces monocytes to differentiate into antigen-presenting cells (APCs). Here we report differential gene expression analysis with BCG-CWS-stimulated versus nonstimulated monocytes. BCG-CWS exerted massive induction of genes regulated by TLR signaling. Marked gene regulatory characteristics in BCG-CWS-stimulated cells compared to lipopolysaccharide (LPS)-stimulated cells follow. (i) Spliced mRNAs encoding soluble forms of TREM-1 and TREM-2 (recently discovered inflammatory-signal-amplifying receptors) were regulated by BCG-CWS, resulting in their differential expression. (ii) The genes for zinc-iron transporter protein (ZIP)-like family proteins HKE-1 and LIV-1 were induced exclusively by BCG-CWS. (iii) Interleukin-23 (IL-23), rather than IL-12p70, was induced by BCG-CWS, while interferon-inducible genes were induced only by LPS. By Northern and reverse transcription-PCR analyses, we confirmed the differential expression of more than 30 BCG-CWS regulatory genes, and their expression was compared with that of LPS and other known TLR ligands. A battery of genes responded rapidly and for a short time to LPS but for a long time to BCG-CWS. Structural analysis of the identified novel or hypothetical proteins revealed that some are potential candidates as signaling mediators or transcriptional regulators. Hence, BCG-CWS may profoundly modulate APC responses in a way distinct from that of LPS, leading to possible advantages for its adjuvant-active therapeutic potential.

Adjuvants, Immunologic↗
PubMed2001

Development of a method for mRNA differential display in filamentous fungi: comparison of mRNA differential display reverse transcription polymerase chain reaction and cDNA amplified fragment length polymorphism in Leptosphaeria maculans.

We modified a technique, cDNA-AFLP, for identifying differentially expressed genes in plants to work in the filamentous fungus Leptosphaeria maculans (Desmaz.) Ces. & De Not. The cDNA fragments generated by our method ranged in size from approximately 100 to 400 bps. On average, twice as many cDNA fragments were amplified per primer set with cDNA amplified fragment length polymorphism in comparison with mRNA differential display reverse transcription polymerase chain reaction. The DNA fragments of interest were excised from gels and analyzed by single-stranded conformation polymorphism to eliminate nondifferentially expressed cDNA contamination. The method was used to examine gene expression differences between cultures grown in the presence or absence of an analog of the Brassica phytoalexin brassinin. Eleven of the fourteen fragments examined were determined by reverse Northern blot to be differentially expressed. In examining gene expression differences between young cultures not producing sirodesmins and older cultures that were producing these phytotoxins, we found 17 of 25 fragments were differentially expressed. Northern blots with these fragments confirmed the results.

Ascomycota↗
PubMed2006

Karyotype differentiation in Chromaphyosemion killifishes (Cyprinodontiformes, Nothobranchiidae). II: cytogenetic and mitochondrial DNA analyses demonstrate karyotype differentiation and its evolutionary direction in C. riggenbachi.

African killifishes of the genus Chromaphyosemion show a high degree of phenotypic and karyotypic diversity. The latter is especially pronounced in C. riggenbachi, a morphologically defined species restricted to a small distribution area in Cameroon. This study presents a detailed reconstruction of karyotype differentiation within C. riggenbachi using conventional Giemsa staining and sequential chromosome banding as well as a phylogenetic analysis based on part of the mitochondrial (mt) cytochrome b gene from eleven populations. The cytogenetic analysis revealed differences in chromosome morphology, banding patterns and/or diploid chromosome number (2n) among all populations examined. Diploid number ranged from 2n = 20 to 2n = 36 and varied mainly among populations, while C-banding patterns and NOR phenotypes showed fixed differences among populations as well as some variability within populations. The mtDNA analysis disclosed five clearly differentiated haplotype groups. Mapping the karyotype data onto the mtDNA dendrogram revealed a decrease in 2n from the most basal to the most derived groups, thus demonstrating a reduction of 2n during their evolutionary history. Our results indicate that karyotype differentiation involved Robertsonian fusions as well as non-Robertsonian processes. Causes of the high karyotypic variability may include an elevated chromosomal mutation rate as well as certain features of the ecology and mating system that could facilitate the fixation of chromosomal rearrangements. The pattern of karyotype and haplotype differentiation and the results of previous crossing experiments suggest incipient speciation in C. riggenbachi.

Africa↗
PubMed2004

Determination of cell capacitance using the exact empirical solution of partial differential Y/partial differential Cm and its phase angle.

Measures of membrane capacitance offer insight into a variety of cellular processes. Unfortunately, popular methodologies rely on model simplifications that sensitize them to interference from inevitable changes in resistive components of the traditional cell-clamp model. Here I report on a novel method to measure membrane capacitance that disposes of the usual simplifications and assumptions, yet is immune to such interference and works on the millisecond timescale. It is based on the exact empirical determination of the elusive partial derivative, partial differential Y/partial differential C(m), which heretofore had been approximated. Furthermore, I illustrate how this method extends to the vesicle fusion problem by permitting the determination of partial differential Y(v)/partial differential C(v), thereby providing estimates of fusion pore conductance and vesicle capacitance. Finally, I provide simulation examples and physiological examples of how the method can be used to study processes that are routinely interrogated by measures of membrane capacitance.

Algorithms↗
PubMedDate not supplied

High-resolution CT characteristics of poorly differentiated adenocarcinoma of the peripheral lung: comparison with well differentiated adenocarcinoma.

OBJECTIVE: The purpose of this study was to elucidate the characteristic high-resolution CT (HRCT) findings of poorly differentiated adenocarcinoma (PDA) in comparison with those of well differentiated adenocarcinoma (WDA). MATERIALS AND METHODS: We investigated the HRCT features of surgically resected PDAs (n=21) and WDAs (n=31). We analyzed the margin, CT attenuation, and internal architecture of the tumor and findings in the surrounding lung field, comparing them with the corresponding pathologic findings. RESULTS: Smoothness of the greater part (full-1/2 round) of the tumor and solid appearance were more prevalent in PDAs than WDAs (81% vs. 32%, 100% vs. 35%) [p<0.01]. Air-bronchogram was prevalent in WDAs (58%), but was never seen in PDAs [p<0.01]. Ground-glass opacity in PDAs pathologically corresponded to inflammation and edema in the alveolar space. CONCLUSIONS: Smoothness of the tumor margin and solid appearance without air-bronchogram were more commonly found in PDA than in WDA. HRCT may predict the histological differentiation of adenocarcinoma in selected cases in which differentiation is inconclusive by sputum cytology and transbronchial or CT-guided biopsy.

Adenocarcinoma↗
PubMed1999

Differential gene expression in retina of myopic chicken eyes using mRNA differential display.

PURPOSE: To study differentially expressed genes in retina of experimental myopic chicken. METHODS: Experimental myopia in chicken was induced by form-deprivation. The mRNA in chicken retina was analyzed by using differential display. RESULTS: Experimental myopia was successfully induced in chicken through form-deprivation. Differentially expressed gene fragments were detected in retina of chicken with myopic development and recovery as compared with normal controls. CONCLUSION: The differential display of mRNA may be a useful way in cloning myopic-related genes.

Animals↗
PubMed2005

Demonstration of differential gene expression between sensitive and resistant ovarian tumor cells by fluorescence differential display-PCR analysis.

Chemotherapy plays a major role in cancer management; however, acquired drug resistance remains a significant problem for ovarian cancer treatment. Chemoresistance is regulated by the coordinated expression of a set of genes. Thus, the identification of genes specifically modulated in the process provides an important step toward the discovery of underlying molecular mechanisms in drug resistance events. We recently developed five drug-resistant human ovarian carcinoma cell lines, including two cisplatin (cis) resistant cell lines, two carboplatin (car) resistant cell lines and one taxol (tax) resistant cell line. In this study, we investigated differential gene expression between these resistant cell lines and their parental cell lines by the fluorescence differential display-polymerase chain reaction (FDD-PCR) technique. We first screened and identified differentially expressed genes in the resistant ovarian cancer cell lines, and we then sequenced and analyzed these genes by bioinformatics software. A total of 33 fragments were displayed in the two resistant cell lines (S-cis and S-car) derived from the sensitive SKOV-3 cell line, and 36 fragments were displayed in the three resistant cell lines (A-cis, A-car and A-tax) derived from the sensitive A2780 cell line. After purification, cloning, sequencing, and homology analysis on the NCBI BLAST GenBank, 12 gene fragments were identified from the resistant S-cis and S-car cells, and 23 gene fragments were identified from the resistant A-cis, A-car and A-tax cells. Although a homolog search of the NIH GenBank revealed that most of the gene fragments were not significantly associated with the known drug resistance-related genes, our study conclusively demonstrates that FDD-PCR is a useful tool for analyzing the differential gene expression between resistant and sensitive tumor cells and for identifying novel chemoresistance-associated genes and potential biological markers or genetic markers of drug resistance.

Base Sequence↗
PubMed1988

Terminally differentiated neonatal rat myocardial cells proliferate and maintain specific differentiated functions following expression of SV40 large T antigen.

Early in neonatal development, differentiated myocardial cells lose their ability to proliferate, and further enlargement of the heart occurs through hypertrophy of existing cardiac muscle cells. To study the process of myocardial growth and hypertrophy we have recently utilized a neonatal rat myocardial cell model (Lee, H. R., Henderson, S. A., Reynolds, R., Dunnmon, P., Yuan, D., and Chien, K. R. (1988) J. Biol. Chem. 263, 7352-7538). The present study was designed to determine if the expression of SV40 large T antigen would be capable of restoring the proliferative capacity of terminally differentiated neonatal rat myocardial cells. Utilizing a replication-defective recombinant human adenovirus which contains an SV40 early T antigen insert, maximal expression of T antigen was achieved at 24-48 h postinfection, with over 85-90% of the cells displaying positive T antigen staining. Furthermore, the expression of the T antigen-induced proliferation of the myocardial cells without the loss of expression of certain differentiated properties, including myosin light chain expression and assembly into organized myofibrils, spontaneous contractile activity, and a chronotropic response to adrenergic agonists. These results demonstrate the utility of recombinant human adenoviruses to achieve high efficiency transient expression of foreign genes in differentiated myocardial cells and suggest that the expression of T antigen may provide a suitable model to study the biochemical events which are required to maintain the proliferative capacity of myocardial cells.

Animals↗
PubMed1996

Identification by differential display of annexin-VI, a gene differentially expressed during melanoma progression.

To identify genes involved in the melanocyte to malignant melanoma conversion, we have applied differential display to the comparison of syngeneic murine B16F10 (metastatic melanoma) and Melan-a-immortalized melanocyte cell lines. Approximately 7000 bands were analyzed, revealing approximately 80 to be differentially displayed. Reverse Northern blotting and subsequent Northern blotting confirmed the reproducible differential expression of four transcripts. Three B16F10-specific bands encode novel genes or partially sequenced cDNAs of unknown function. One Melan-a-specific band was found to be identical to the 3' end region of the mouse Annexin VI mRNA and shown to have a reduced message expression in B16F10 relative to Melan-a. Differential expression was confirmed at the protein level with Western blotting using a rabbit polyclonal antiserum. Immunohistochemistry of human melanoma specimens with this antiserum revealed a decrease or loss of Annexin VI expression as melanomas progressed from a benign to a more malignant phenotype. Our results provide further evidence for a potential role of Annexin VI in tumor suppression.

Animals↗
PubMed1997

Differential expression of mitochondrial NADH dehydrogenase in ethanol-treated rat brain: revealed by differential display.

The technique of polymerase chain reaction (PCR) differential display was used to detect alterations in gene expression after chronic alcohol administration. Male Wistar rats were treated with ethanol vapor for 14 days. The cDNA generated from mRNA isolated from the hippocampi of ethanol-treated and control animals was compared by PCR differential display. A differentially expressed cDNA fragment was used to screen mRNA samples by Northern analysis. The level of a mRNA was significantly elevated (x 2.5) in the hippocampus, but not the cortex of alcohol-treated rats up to 48 hr after withdrawal. Sequence analysis of the cDNA fragment revealed an almost perfect homology to rat mitochondrial NADH dehydrogenase subunit 4 mRNA. The selective induction of this mRNA in alcohol-treated rat brain areas suggests altered metabolic processes and possible dysfunction of the mitochondria. The technique of PCR differential display may prove useful in further analysis of gene expression during alcohol dependence and withdrawal.

Alcoholism↗
PubMed1994

Sexual differentiation in the CNS of the moth, Manduca sexta. I. Sex and segment-specificity in production, differentiation, and survival of the imaginal midline neurons.

We analyzed the development of several sets of postembryonic sex-specific motoneurons in Manduca sexta which belong to a group of homologous lineages of neurons called the imaginal midline neurons (IMNs). Adult female oviduct motoneurons and male sperm duct motoneurons are IMNs that show similar anatomical features and differentiate during metamorphosis, despite appearing in different segments: A7 for oviduct neurons, A9 for sperm duct neurons. These cells are born at the same time and, initially, similar sets are found in A7 and A9 ganglia of larvae of both sexes. The dimorphic adult pattern is generated by sex-specific production and cell death. A7 IMNs differentiate in both sexes through early pupal stages, whereupon they disappear in the male and become the oviduct motoneurons in the female. A9 IMNs are overproduced in the male, and subsequent cell death reduces male cell number and eliminates the small complement of female cells; the surviving male cells develop into the sperm duct motoneurons. Similar IMN arrays are generated in nongenital ganglia, but show non-sex-specific fates. This suggests that both the sex of these cells and their segment of residence play major roles in their subsequent differentiation.

Animals↗
PubMed1994

Differential distribution of the alpha 6 subunit of integrins in the development and sexual differentiation of the mouse testis.

The distribution of the alpha 6 subunit of integrins in the development and sexual differentiation of mouse testis was analyzed by light and electron microscopy during the embryonic, fetal and early postnatal periods. At the pregonadal phase only the epithelial cells of the mesonephric duct and of the distal mesonephric tubules showed a reaction to alpha 6, whereas the surface epithelium and the mesenchyme of the mesonephros were negative or contained only a rudimentary amount of the alpha 6 subunit. With the formation of the gonadal ridge and the testicular blastema, the gonadal cells became positive for the alpha 6 subunit. This expression remained in embryonic cord cells and in the vascular endothelial cells, whereas the differentiating cells of the surface epithelium, tunica albuginea, the Leydig cells, and the interstitial mesenchymal cells were negative. With the fetal and postnatal differentiation, the expression of the alpha 6 subunit gradually diminished in the cord cells, and by the prepubertal phase, alpha 6 was found only at adhesion sites between some Sertoli cells. Similar changes were seen in the mesonephric duct and tubules, and in the rete cords. The presence of alpha 6 in regions undergoing developmental cell aggregation processes and their disappearance during tissue maturation, suggest that alpha 6 plays a specific but transient role in gonadal cell adhesion necessary for the histogenetic organization of the testis. In addition to its role in developing and organizing cells, alpha 6 integrin was also a prominent component in degenerating cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗