Potential of the learning vector quantizer in the cell classification of endometrial lesions in postmenopausal women

OBJECTIVE: To investigate the potential of artificial neural networks for cell identification in endometrial lesions from postmenopausal women. STUDY DESIGN: The study was performed on cytologic material obtained by the Gynoscann endometrial cell samplerfrom 12 cases of atrophic endometrium, 48 cases of hyperplasia without cytologic atypia (18 cases of simple hyperplasia and 30 cases of complex hyperplasia), 12 cases of hyperplasia with cytologic atypia (complex atypical hyperplasia) and 48 cases of adenocarcinoma (30 cases of well-differentiated, 12 cases of moderately differentiated and 6 cases of poorly differentiated carcinoma). From each case approximately 100 cells were examined using a custom image analysis system. A learning vector quantizer (LVQ) identified the collected data. RESULTS: Investigation of cells from Endometrial Alterations with LVQ proved that according to the nuclear characteristics, as expressed by morphometric and textural measures, the endometrial cells from postmenopausal women may be identified as belonging to one of thefollowing three groups: atrophy, hyperplasia without cytologic atypia (simple and complex hyperplasia) and malignant neoplastic lesions (atypical complex and adenocarcinoma). CONCLUSION: The role of nuclear morphologic features in the cytologic diagnosis of endometrial alterations was confirmed. The overlap in thefeature space observed indicates that cell characteristics do not form strictly separate clusters. Thatfact explains the difficulty that morphologists have with the reproducible identification of cells from endometrial lesions in postmenopausal women. Application of LVQ offers a good classification at the cell level and promises to be a powerful toolfor classification on the individual patient level andfor the clarification of the natural history of endometrial pathology.     

Interaction between human MCM7 and Rad17 proteins is required for replication checkpoint signaling

Human Rad17 (hRad17) is centrally involved in the activation of cell-cycle checkpoints by genotoxic agents or replication stress. Here we identify hMCM7, a core component of the DNA replication apparatus, as a novel hRad17-interacting protein. In HeLa cells, depletion of either hRad17 or hMCM7 with small-interfering RNA suppressed ultraviolet (UV) light- or aphidicolin-induced hChk1 phosphorylation, and abolished UV-induced S-phase checkpoint activation. Similar results were obtained after transfection of these cells with a fusion protein containing the hMCM7-binding region of hRad17. The hMCM7-depleted cells were also defective for the formation of ATR-containing nuclear foci after UV irradiation, suggesting that hMCM7 is required for stable recruitment of ATR to damaged DNA. These results demonstrate that hMCM7 plays a direct role in the transmission of DNA damage signals from active replication forks to the S-phase checkpoint machinery in human cells.     

Characterization of transgenic mice with targeted disruption of the catalytic domain of the double-stranded RNA-dependent protein kinase, PKR

The interferon-inducible, double-stranded RNA-dependent protein kinase PKR has been implicated in anti-viral, anti-tumor, and apoptotic responses. Others have attempted to examine the requirement of PKR in these roles by targeted disruption at the amino terminal-encoding region of the Pkr gene. By using a strategy that aims at disruption of the catalytic domain of PKR, we have generated mice that are genetically ablated for functional PKR. Similar to the other mouse model of Pkr disruption, we have observed no consequences of loss of PKR on tumor suppression. Anti-viral response to influenza and vaccinia also appeared to be normal in mice and in cells lacking PKR. Cytokine signaling in the type I interferon pathway is normal but may be compromised in the erythropoietin pathway in erythroid bone marrow precursors. Contrary to the amino-terminal targeted Pkr mouse, tumor necrosis factor alpha-induced apoptosis and the anti-viral apoptosis response to influenza is not impaired in catalytic domain-targeted Pkr-null cells. The observation of intact eukaryotic initiation factor-2alpha phosphorylation in these Pkr-null cells provides proof of rescue by another eukaryotic initiation factor-2alpha kinase(s).     

Herbarium specimens demonstrate earlier flowering times in response to warming in Boston

Museum specimens collected in the past may be a valuable source of information on the response of species to climate change. This idea was tested by comparing the flowering times during the year 2003 of 229 living plants growing at the Arnold Arboretum in Boston, Massachusetts, USA, with 372 records of flowering times from 1885 to 2002 using herbarium specimens of the same individual plants. During this period, Boston experienced a 1.5°C increase in mean annual temperature. Flowering times became progressively earlier; plants flowered 8 d earlier from 1980 to 2002 than they did from 1900 to 1920. Most of this shift toward earlier flowering times is explained by the influence of temperature, especially temperatures in the months of February, March, April, and May, on flowering time. Plants with a long flowering duration appear to be as useful for detecting responses to changing temperatures as plants with a short flowering duration. Additional studies using herbarium specimens to detect responses to climate change could examine specimens from specific, intensively collected localities, such as mountain peaks, islands, and unique habitats.     

The acroplaxome is the docking site of Golgi-derived myosin Va/Rab27a/b- containing proacrosomal vesicles in wild-type and Hrb mutant mouse spermatids

Acrosome biogenesis involves the transport and fusion of Golgi-derived proacrosomal vesicles along the acroplaxome, an F-actin/keratin 5-containing cytoskeletal plate anchored to the spermatid nucleus. A significant issue is whether the acroplaxome develops in acrosomeless mutant mice. Male mice with a Hrb null mutation are infertile and both spermatids and sperm are round-headed and lack an acrosome. Hrb, a protein that contains several NPF motifs (Asn-Pro-Phe) and interacts with proteins with Eps15 homology domains, is regarded as critical for the docking and/or fusion of Golgi-derived proacrosomal vesicles. Here we report that the lack of an acrosome in Hrb mutant spermatids does not prevent the development of the acroplaxome. Yet the acroplaxome in the mutant contains F-actin but is deficient in keratin 5. We also show that the actin-based motor protein myosin Va and its receptor, Rab27a/b, known to be involved in vesicle transport, are present in the Golgi and Golgi-derived proacrosomal vesicles in wild-type and Hrb mutant mouse spermatids. In the Hrb mutant, myosin-Va-bound proacrosome vesicles tether to the acroplaxome, where they flatten and form a flat sac, designated pseudoacrosome. As spermiogenesis advances, round-shaped spermatid nuclei of the mutant display several nuclear protrusions, designated nucleopodes. Nucleopodes are consistently found at the acroplaxome- pseudoacrosome site. Our findings support the interpretation that the acroplaxome provides a focal point for myosin-Va/ Rab27a/b-driven proacrosomal vesicles to accumulate, coalesce, and form an acrosome in wild-type spermatids and a pseudoacrosome in Hrb mutant spermatids. We suggest that nucleopodes develop at a site where a keratin 5-deficient acroplaxome may not withstand tension forces operating during spermatid nuclear shaping.     

Endothelin-1 induces expression of matrix-associated genes in lung fibroblasts through MEK/ERK

The endothelins are a family of endothelium-derived peptides that possess a variety of biological activities, including potent vasoconstriction. Endothelin-1 (ET-1) is up-regulated during tissue repair and pulmonary fibrosis. Here, we use genome-wide expression array analysis to show that the addition of ET-1 (100 nm, 4 h) to normal lung fibroblasts directly induces expression of matrix and matrix-associated genes, including the profibrotic protein CCN2 (connective tissue growth factor, or CTGF). ET-1 induces the MEK/ERK MAP kinase pathway in fibroblasts. Blockade of the MEK/ERK kinase pathway with U0126 abrogates the ability of ET-1 to induce expression of matrix and matrix-associated mRNAs and the CCN2 protein. The CCN2 promoter possesses an ET-1 response element, which maps to the previously identified basal control element-1 (BCE-1) site. Our results suggest that ET-1 induces a program of matrix synthesis in lung fibroblasts and that ET-1 may play a key role in connective tissue deposition during wound repair and in pulmonary fibrosis.     

Interaction between altered insulin and lipid metabolism in CEACAM1-inactive transgenic mice

Inactivation of CEACAM1 in L-SACC1 mice by a dominant-negative transgene in liver impairs insulin clearance and increases serum free fatty acid (FFA) levels, resulting in insulin resistance. The contribution of elevated FFAs in the pathogenesis of insulin resistance is herein investigated. Treatment of L-SACC1 female mice with carnitine restored plasma FFA content. Concomitantly, it normalized insulin levels without directly regulating receptor-mediated insulin internalization and prevented glucose tolerance in these mice. Similarly, treatment with nicotinic acid, a lipolysis inhibitor, restored insulin-stimulated receptor uptake in L-SACC1 mice. Taken together, these data suggest that chronic elevation in plasma FFAs levels contributes to the regulation of insulin metabolism and action in L-SACC1 mice.