Vascular integrins: pleiotropic adhesion and signaling molecules in vascular homeostasis and angiogenesis

New blood vessel formation, a process referred to as angiogenesis, is essential for embryonic development and for many physiological and pathological processes during postnatal life, including cancer progression. Endothelial cell adhesion molecules of the integrin family have emerged as critical mediators and regulators of angiogenesis and vascular homeostasis. Integrins provide the physical interaction with the extracellular matrix necessary for cell adhesion, migration and positioning, and induction of signaling events essential for cell survival, proliferation and differentiation. Antagonists of integrin alpha V beta 3 suppress angiogenesis in many experimental models and are currently tested in clinical trials for their therapeutic efficacy against angiogenesis-dependent diseases, including cancer. Furthermore, interfering with signaling pathways downstream of integrins results in suppression of angiogenesis and may have relevant therapeutic implications. In this article we review the role of integrins in endothelial cell function and angiogenesis. In the light of recent advances in the field, we will discuss their relevance as a therapeutic target to suppress tumor angiogenesis.

Influence of hyperbranched multi-methacrylates for dental neat resins on proliferation of human gingival fibroblasts

We have previously shown that hyperbranched multi-methacrylate (H-MMA)-modified dental resins have VLC activities, lower polymerization shrinkage, and improved mechanical properties, compared to the 2,2-bis[4-(2-hydroxy-3-methacryloyolxypropoxy)phenyl]propane/triethyleneglycol dimethacrylate (BisGMA/TEGDMA) neat resin. The results are due to the unique molecular structure and high molecular weight of H-MMA intermediates. The purpose of this study was to evaluate the biocompatibility of H-MMA-modified dental neat resins. The cell proliferation of three human gingival fibroblast strains on either H-MMA, BisGMA/TEGDMA, or a polystyrene disk was examined. Following 10 days of cell proliferation, there was no statistical difference in cell number between H-MMA-modified and unmodified resin disks. H-MMA-modified resins had less free monomer leaching than the unmodified resin but showed similar properties in water sorption and contact angle values. All these results suggest that the biocompatibility of H-MMA-modified dental neat resins is as good as that of commercially used BisGMA/TEGDMA resin and H-MMA has potential applications in dental composites.

Immediate placement of anatomically shaped dental implants

Immediate placement of dental implants into tooth extraction sites is an effective treatment option. When immediate placement procedures are performed with a round implant, a void is often evident between the implant and the orifice of the socket. Previous treatment focused on the use of membranes or special closure techniques to induce bone growth into the void. Anatomically shaped dental implants provide a predictable alternative to previous filling techniques since the anatomical implants decrease or completely fill the void at the socket opening. This article describes a surgical technique developed for the immediate placement of these implants in extraction sites.

Immune reconstitution after autologous peripheral blood progenitor cell transplantation: effect of interleukin-15 on T-cell survival and effector functions

OBJECTIVE

The aim of this study was to evaluate the occurrence of T-cell spontaneous apoptosis (A(spont)) and its modulation in vitro by the interleukin-2 receptor (IL-2R) gamma-chain (gammac)-signaling cytokine IL-15 in patients transplanted with autologous peripheral blood progenitor cells (PBPC) for hematologic malignancies.

MATERIALS AND METHODS

Patients were examined on days 30-60, 60-90, and 90-120 after PBPC infusion. Dissipation of mitochondrial transmembrane potential, a hallmark of T-cell apoptosis, has been detected using the fluorescent probe 3,3'-dihexyloxacarbocyanine iodide, after short-term T-cell culture in the absence or presence of exogenous cytokines. Expression of Bcl-2 family members has been studied by flow cytometry and reverse transcriptase polymerase chain reaction. T-cell proliferative responses to recall antigens have been estimated in autologous mixed leukocyte cultures.

RESULTS

A(spont) was seen in 45% +/- 6% of CD4(+) and 55% +/- 6% of CD8(+) T cells cultured in the absence of cytokines. Of interest, IL-15 and, to a lesser extent, its structural cousin IL-2 counteracted T-cell A(spont) by inhibiting the processing of caspase-3 and up-regulating Bcl-2 mRNA and protein levels. Cell division tracking confirmed that IL-15 did not rescue T cells from A(spont) by promoting proliferation but rather acted as a genuine survival factor. Addition of a gammac-blocking antibody to cytokine-conditioned cultures abrogated both apoptosis inhibition and Bcl-2 induction by IL-15, suggesting involvement of the IL-2Rgammac signal transduction pathway. Whereas cytokine-unprimed posttransplant T cells mounted inadequate responses to recall antigens, T cells conditioned with IL-15 expanded vigorously, indicating restoration of antigen-specific proliferation.

CONCLUSIONS

T cells recovering after autologous PBPC transplantation are highly susceptible to spontaneous apoptosis in vitro. This phenomenon can be counteracted by the gammac-signaling cytokine IL-15. These findings suggest that IL-15 might be a promising immunomodulating agent to improve postgrafting T-cell function.

Experimental gingivitis in women using oral contraceptives

Oral contraceptives (OC) have historically been considered a risk factor for gingival diseases. We set out to investigate this premise further, given that, over recent years, hormone concentrations in OC have been substantially reduced. Using a prospective, split-mouth, experimental gingivitis model, pre-menopausal women either taking (n 14) or not taking (n = 16) OC refrained from all oral hygiene practices in one maxillary (test) quadrant while continuing to perform normal oral hygiene activities in the contralateral (control) quadrant. Mean increases in plaque index (PI), gingival index (GI), and gingival crevicular fluid (GCF) volume from days 0 to 21 were significant in test quadrants (P < 0.05) but did not differ regardless of whether subjects received OC (P > 0.05). PI, GI, and GCF volume did not vary in control quadrants over the course of the study (P > 0.05). Analysis of these data suggests that current OC formulations do not affect the inflammatory response of the gingiva to dental plaque.

EGF-R signaling through Fyn kinase disrupts the function of integrin alpha6beta4 at hemidesmosomes: role in epithelial cell migration and carcinoma invasion

We have examined the mechanism and functional significance of hemidesmosome disassembly during normal epithelial cell migration and squamous carcinoma invasion. Our findings indicate that a fraction of EGF receptor (EGF-R) combines with the hemidesmosomal integrin alpha6beta4 in both normal and neoplastic keratinocytes. Activation of the EGF-R causes tyrosine phosphorylation of the beta4 cytoplasmic domain and disruption of hemidesmosomes. The Src family kinase inhibitors PP1 and PP2 prevent tyrosine phosphorylation of beta4 and disassembly of hemidesmosomes without interfering with the activation of EGF-R. Coimmunoprecipitation experiments indicate that Fyn and, to a lesser extent, Yes combine with alpha6beta4. By contrast, Src and Lck do not associate with alpha6beta4 to a significant extent. A dominant negative form of Fyn, but not Src, prevents tyrosine phosphorylation of beta4 and disassembly of hemidesmosomes. These observations suggest that the EGF-R causes disassembly of hemidesmosomes by activating Fyn, which in turn phosphorylates the beta4 cytoplasmic domain. Neoplastic cells expressing dominant negative Fyn display increased hemidesmosomes and migrate poorly in vitro in response to EGF. Furthermore, dominant negative Fyn decreases the ability of squamous carcinoma cells to invade through Matrigel in vitro and to form lung metastases following intravenous injection in nude mice. These results suggest that disruption of hemidesmosomes mediated by Fyn is a prerequisite for normal keratinocyte migration and squamous carcinoma invasion.

Tyrosine phosphorylation of the beta 4 integrin cytoplasmic domain mediates Shc signaling to extracellular signal-regulated kinase and antagonizes formation of hemidesmosomes

Ligation of the alpha(6)beta(4) integrin induces tyrosine phosphorylation of the beta(4) cytoplasmic domain, followed by recruitment of the adaptor protein Shc and activation of mitogen-activated protein kinase cascades. We have used Far Western analysis and phosphopeptide competition assays to map the sites in the cytoplasmic domain of beta(4) that are required for interaction with Shc. Our results indicate that, upon phosphorylation, Tyr(1440), or secondarily Tyr(1422), interacts with the SH2 domain of Shc, whereas Tyr(1526), or secondarily Tyr(1642), interacts with its phosphotyrosine binding (PTB) domain. An inactivating mutation in the PTB domain of Shc, but not one in its SH2 domain, suppresses the activation of Shc by alpha(6)beta(4). In addition, mutation of beta(4) Tyr(1526), which binds to the PTB domain of Shc, but not of Tyr(1422) and Tyr(1440), which interact with its SH2 domain, abolishes the activation of ERK by alpha(6)beta(4). Phenylalanine substitution of the beta(4) tyrosines able to interact with the SH2 or PTB domain of Shc does not affect incorporation of alpha(6)beta(4) in the hemidesmosomes of 804G cells. Exposure to the tyrosine phosphatase inhibitor orthovanadate increases tyrosine phosphorylation of beta4 and disrupts the hemidesmosomes of 804G cells expressing recombinant wild type beta(4). This treatment, however, exerts a decreasing degree of inhibition on the hemidesmosomes of cells expressing versions of beta(4) containing phenylalanine substitutions at Tyr(1422) and Tyr(1440), at Tyr(1526) and Tyr(1642), or at all four tyrosine phosphorylation sites. These results suggest that beta(4) Tyr(1526) interacts in a phosphorylation-dependent manner with the PTB domain of Shc. This event is required for subsequent tyrosine phosphorylation of Shc and signaling to ERK but not formation of hemidesmosomes.

Assessment of the contaminant concentration variability among Lake Geneva Arctic char using stable isotopic composition (delta15N and delta13C)

Measurements of organochlorine [polychlorinated biphenyls (PCBs) and dichloro-diphenyl-dichloroethylene (DDE)] and Hg concentrations and nitrogen and carbon stable isotopic compositions (delta15N and delta13C) were performed on 63 Arctic char (Salvelinus alpinus) from Lake Geneva. Fish exhibited a high interindividual variablity in pollutant concentrations. Since the accumulation of such persistent contaminants is obtained from food, the co-occurrence of dietary differentiation leading to the contaminant interindividual variability was suspected. delta15N and delta13C were used for assessing trophic position and food source differences among Arctic char. The low ranges of delta15N and delta13C could not explain the interindividual variability in pollutant concentrations. The lack of relation between delta15N and contaminant concentration did not suggest a trophic level biomagnification of PCB, DDE, and Hg. Lake Geneva spatial variability in pollutants may be an important factor of variability within the Arctic char population. The bioaccumulation pattern occurring for Hg was not apparent for PCB and DDE. Organochlorines are hydrophobic contaminants, and their bioaccumulation pattern may be masked by seasonal variations in fish lipid content.

Acoustic energy affects human gingival fibroblast proliferation but leaves protein production unchanged

BACKGROUND, AIMS

Sonic toothbrushes are well-established in oral home care for plaque removal; however, the effects of low frequency acoustic (sonic) energy released from sonic toothbrushes to the cells of the periodontium have not been investigated. The purpose of this study was to evaluate the effects of sonic energy on human gingival fibroblast proliferation and protein production in cell culture.

METHODS

Direct and indirect transfer calibration studies found the fundamental frequency of the Sonicare sonic toothbrush to be 261 hertz (Hz) with amplitudes ranging from 70 to 104 decibels (dB) in the human periodontium. Using an in vitro delivery system, which coupled a signal-wave generator with a bone transducer to mimic the energy delivered by the Sonicare toothbrush, the effects of signal, amplitude and duration were evaluated longitudinally using a gingival fibroblast cell culture model. 8 strains of fibroblasts isolated from healthy human gingiva were seeded at 30,000 cells/35 mm culture dish in minimum essential medium supplemented with 10% fetal bovine serum. To ascertain the relationship of the amplitude and the duration of sonic stimulation to cellular proliferation, gingival fibroblasts were subjected 2x daily to 261 Hz sound at various amplitudes (67-97 dB) for 0, 15, 30, 60, and 120 s on days 1, 3, 5, 7, and 10.

RESULTS

It was found that either 30 or 120 s of sound exposure for 10 days of treatment had significant effects on cell proliferation in comparison to control cultures. Specifically, at day 10, 87 dB at 261 Hz for 30 s 2x daily resulted in a 25.5% increase in cell number (p<0.001), whereas 87 dB at 261 Hz for 120 s twice daily caused a 30.9% decrease in cell number (p<0.001) when compared to control cultures. When cells are stimulated under optimum acoustic conditions for 10 days, there was no difference between the treatment and control groups for collagen (p=0.897) or noncollagen (p=0.697) protein production.

CONCLUSIONS

Sonic energy has been shown to both increase and decrease cellular proliferation depending on exposure time; however, during optimum sound-induced conditions for cellular proliferation, sonic energy had no effect on fibroblast protein production. These data suggest that sonic energy can affect the behavior of cells in culture. Further research into the mechanisms of these changes will provide important information for manipulating cellular behavior.

Gender-specific differences in temporomandibular retrodiscal tissues of the goat

Healthy, adult, male and female goat temporomandibular retrodiscal tissues were characterized to determine if biochemical differences existed between the genders. RNA concentrations were not different between male and female retrodiscal tissues; however, the DNA concentration in female retrodiscal tissues was 82% greater than in male retrodiscal tissues. Collagen concentrations were significantly greater in male retrodiscal tissues, and this was reflected in significant gender differences of type I and III collagen concentrations. More specifically, male temporomandibular retrodiscal tissues contained 70% more type I collagen and 119% more type III collagen when compared to female retrodiscal tissues. These differences in collagens and DNA reflect a gender difference in temporomandibular retrodiscal tissue composition that underlies divergent biomechanical and neurophysiological properties.

Color-Doppler sonography in ophthalmology

BACKGROUND

With the present study we considered ocular blood flow by the use of color Doppler ultrasound. We compared the most clinically important arteries of both eyes. We valued the central retinal artery, the posterior long ciliary arteries, the posterior brief ciliary arteries and the central retinal vein.

METHODS

We submitted to an ecd examination of the ophthalmic arteries 50 patients, of whom 30 were healthy, 4 presented a pallor of the optic disk, 6 were affected by chronic simple glaucoma and 10 were affected by arterial hypertension.

RESULTS

This study has allowed us to define the normal and pathologic anatomic findings at the ecd tracing therefore qualitative and quantitative standards of this examination, repeatable and comparable.

CONCLUSIONS

Currently the different techniques used to study ocular blood flow, do not allow its exact detection, but only a morphological evaluation of the eye artero-venous system. Acquisition of morphological and velocimetric data, at the same time, allows a more exact evaluation of the pathology. Therefore the ecd is a simple rapid and non-invasive approach, useful in the acquisition of important data concerning diagnostic confirmation, prognosis, and above all pharmacological follow-up of many pathologies such as diabetes, glaucoma and arterial hypertension. The diagnosed vascular alterations are correlated to the degree retinopathy and to the effectiveness of the pharmacological treatment.

[Lipids from fossil plants and their relation to modern plants. Example s of Cenomanian flora from Anjou and Bohemia]

Comparative analyses of lipids from fossil plants and from their extant counterparts were undertaken in order to test the taxonomic significance of lipids in palaeobotany. The comparison between lipids from a fossil Ginkgoaceae, Eretmophyllum andegavense, and its extant counterpart, Ginkgo biloba, revealed the presence of original molecules, dimethoxyalkylcoumarins, in lipids from both plants. Such compounds confirm, on chemical grounds the relationship between these extant and fossil Ginkgoaceaes. Moreover, differences in n-alkane distribution between E. andegavense and E. obtusum which are very similar morphologically, confirm that these fossil plants do not belong to the same species. Furthermore, comparative analyses of a fossil Cheirolepidiaceae, Frenelopsis alata, and its extant counterpart, the Cupressaceae Tetraclinis articulata, revealed some similarities between these two species although they do not belong to the same family. Otherwise, comparative analyses of fungi-infected and uninfected samples of F. alata demonstrated that these micro-organisms can significantly affect the chemical composition of fossil plant lipids. In conclusion, even if chemical analyses alone are not sufficient to determine the genus or species of a given fossil plant, they can precise the taxonomy of some specimens that have been previously studied by palaeobotanists.

Dental plaque-induced gingival diseases

Gingival diseases are a diverse family of complex and distinct pathological entities found within the gingiva that are the result of a variety of etiologies. There are several clinical characteristics common to all gingival diseases and these features include clinical signs of inflammation, signs and symptoms that are confined to the gingiva, reversibility of the disease by removing the etiology, the presence of bacterial laden plaque to initiate and/or exacerbate the severity of the disease and a possible role as a precursor for attachment loss around teeth. Defining and classifying gingival diseases has not been an easy task. The tools and methods to identify gingival diseases have varied depending on the criteria used by epidemiologists, researchers, or the practicing clinician. The classification of gingival disease in this review relied upon experimental and/or epidemiological human studies that accurately and reliably assessed an underlying functional derangement that was localized to the gingiva and was reported in a peer-reviewed journal. The classification of gingival diseases that depends on dental plaque to initiate the disease process(es) has been categorized into two groups. The two categories of plaque-induced gingival diseases are those affected by local factors and those that are affected by local factors and modified by specific systemic factors found in the host. In this review, the clinical characteristics of gingival disease associated with plaque, endogenous hormone fluctuations, drugs, systemic diseases, and malnutrition were investigated.

Trauma modifies strength and composition of retrodiscal tissues of the goat temporomandibular joint

OBJECTIVES

Temporomandibular pain is often accompanied by pathologic changes to joint retrodiscal tissues. The substantial representation of females in this condition has encouraged hypotheses which link genetic or hormonally induced abnormalities in tissue composition (type III collagen, type I collagen, type III/type I ratio) to the development of temporomandibular disorders. As this condition is often associated with a history of orofacial trauma, we investigated the functional impact of retrodiscal trauma on the composition and biomechanics of retrodiscal tissues.

DESIGN AND METHODS

Retrodiscal tissue of female goats received trauma or sham trauma. Following a healing period of 30 days, the tissues were pulled to failure on an extensometer.

OUTCOME MEASURES

Assessments were made of tissue biomechanical properties (failure force, elastic stiffness, strain distribution). Tissue fragments were assayed for collagens I and III.

RESULTS

Thirty days after surgical section of retrodiscal tissues, the tissue had reformed, but the composition and biomechanics were substantially changed. Healed tissue manifested less than half the strength of normal tissue (P = 0.02). In addition, the development of tissue strain shifted from a relatively even distribution to a confined region near the retrodiscal-discal attachment zone. It appeared that a large increase in the expression of type III collagen (179.6%; P = 0.038) and the ratio of type III/type I collagen (180.9%; P = 0.011) accounted for these functional changes.

CONCLUSIONS

We suggest that shifts in collagen expression following injury create shifts in strain development which focus tissue stresses near the interface of the disc and retrodiscal tissue, and that this shift dramatically weakens the tissue and increases the probability of re-injury, inflammation and pain.

Combination of biomolecular and stable isotope techniques to determine the origin of organic matter used by bacterial communities: application to sediment

Natural isotopic composition is a good tool to trace organic matter in ecosystems. Recent studies used a combination of molecular and stable isotope techniques to determine the origin of the organic carbon used by bacteria in the water column. In our study, we show that this procedure can be used for analysis of sediment bacterial communities with few modifications. In the water column, bacterial recovery is done before DNA extraction. In the sediment, we tested qualitatively and quantitatively a direct and indirect extraction of DNA. The direct extraction was the most efficient. It recovered between 3.1 and 15.8 microg DNA g(-1) dry sediment and the contamination of field samples by eucaryotic DNA was less than 13%. In this preliminary study of the salt marsh ecosystem, the delta(13)C values of DNA (-26 to - 24%) recovered from the sediment were close to the delta(13)C values of halophytic plants (-26.4 and - 25.3%) showing a relationship between plants and microorganisms. Thus, this procedure can be used to trace the flow of carbon through the sediment microbial biomass and to understand the variation of bacterial activity according to the inputs of allocthonous and autochtonous organic matter.

Measurement of clinical attachment levels using a constant-force periodontal probe modified to detect the cemento-enamel junction

The handpiece of a Florida sleeve probe was modified to create a flange with the capability to detect the cemento-enamel junction (CEJ). This new instrument (the Pressure-controlled, Automated, Standardised Handpiece or Florida PASHA probe) was used to determine whether (a) the CEJ could be reproducibly detected in dried, human skulls and (b) clinical attachment levels could be reliably measured in human subjects. When using the Florida PASHA probe to detect the CEJ at 157 different sites in four dried, human skulls, there were no statistically significant (p > or = 0.15) differences in mean CEJ detection measurements for any of the three participating examiners; either when the CEJ was visualised or obscured. The mean differences between first and second replicates ranged from 0.00 to 0.08 mm. Intraclass correlation coefficients (ICCs) of repeated measures in both conditions ranged from 0.70 to 0.83 for tactile CEJ detection (CEJ obscured), and from 0.95 to 0.96 for visual detection (CEJ visible). In human studies, the Florida PASHA probe was used by two examiners to determine clinical attachment levels (CAL) at 660 sites in 5 human subjects undergoing supportive periodontal therapy. Intra-examiner agreement of replicate measurements recorded by the probe, as measured by calculating ICCs, ranged from 0.79 to 0.85 for the 2 examiners, respectively. A statistically significant inter-examiner difference in mean CAL measurements when using the Florida PASHA probe was found (p<0.001). Notwithstanding this difference, inter-examiner agreement was good, with an ICC of 0.83. These data suggest that the Florida PASHA probe can reproducibly detect the CEJ and is proposed as a tool for measuring CAL in humans.

Kidney vasculogenesis and angiogenesis: role of vascular endothelial growth factor

Vascular Endothelial Growth Factor (VEGF) plays a crucial role in the establishment of the vascular tree pattern. New vessels can be formed by two different ways; in the development of kidney both vasculogenesis and angiogenesis participate to microvessel assembly. VEGF and its receptor (VEGF-R) are co-expressed during kidney organogenesis and stimulate renal blood vessels development, induce and maintain the fenestrated phenotype in endothelium and regulate vascular permeability. VEGF and many other growth factors participate to the development of embryonic glomerular microvasculature. We believe that therapeutical use of VEGF or anti-VEGF antibodies may be performed in the treatment of many disorders.

Primary antiphospholipid syndrome and cerebral atrophy: a rare association?

Neurologic complications are common in patients with antiphospholipid syndrome. In this article, we report the case of a young woman with neurologic disorders, a history of hypertension and transient ischemic attacks, and cerebral atrophy associated with primary antiphospholipid syndrome (PAPS). Magnetic resonance imaging of the brain showed multiple ischemic lesions and remarkable atrophy of frontal and parietal lobes. Cerebral atrophy in patients with PAPS can be considered as a feature of this disease. The case is discussed on the basis of relevant past literature. Although there are few reports on neuroradiologic findings in patients with PAPS, cerebral atrophy has been described. Because PAPS is more frequently recognized today than in the past, this condition should be included in the differential diagnosis of cerebral atrophy, particularly in young patients.

BIS-GMA--based resins in dentistry: are they safe?

BACKGROUND

The authors critically surveyed research dealing with the release of resin components from dental composites and the potential of these agents to mimic or disrupt estrogenic cell responses.

TYPES OF STUDIES REVIEWED

The studies reviewed included those on synthetic methods used to make bisphenol A glycidyl methacrylate, or BIS-GMA, and the biological effects of this resin in cell culture and animals. The estrogenic effect of bisphenol A was targeted because bisphenol A is present as an impurity in some resins (BIS-GMA) and as a degradation product from other resins (bisphenol A dimethacrylate, or BIS-DMA).

RESULTS

The outcomes of this review revealed that short-term administration of BIS-GMA and/or bisphenol A in animals or cell cultures can induce changes in estrogen-sensitive organs or cells. However, considering the dosages and routes of administration and the modest response of estrogen-sensitive target organs, the authors conclude that the short-term risk of estrogenic effects from treatments using bisphenol A-based resins is insignificant. Long-term effects need to be investigated further.

CLINICAL IMPLICATIONS

Commonly used dental resins should not be of concern to the general public; however, pharmacological evaluation of dental materials is needed to ensure biologically safe and therapeutically effective substances.

The in vivo effects of bisGMA on murine uterine weight, nucleic acids and collagen

The aim of this investigation was to evaluate the ability of commercial bisGMA to stimulate growth in an estrogen-sensitive target tissue. Adult, female, Swiss-Webster mice were ovariectomized and received either oil, estradiol (100 microg/kg), or one of two bisGMA doses (25 microg/kg or 100 microg/kg). Starting on the day of surgery, the hormone, drug or oil was injected subcutaneously 3 times a week. After 3 wk of treatment, the animals were sacrificed, the uteri removed, weighed and stored at -80 degrees C for biochemical analysis. The uteri from ovariectomized mice receiving high dose (100 microg/kg) bisGMA or estradiol showed a significant increase in normalized wet weight that was 29% and 786%, respectively, greater than the ovariectomized control uterine normalized weights. In the low bisGMA dose (25 microg/kg) group, normalized uterine wet weights were not statistically significant from ovariectomized controls. Biochemical analyses of uterine tissues revealed that estradiol resulted in maintaining DNA content, RNA content, RNA/DNA ratios and collagen content significantly above the ovariectomized control. Neither the low nor high doses of bisGMA stimulated RNA content, DNA content or RNA/DNA ratios above ovariectomized controls. However, the high dose (100 microg/kg) of bisGMA caused a significant increase above ovariectomized controls in uterine collagen content.

A requirement for caveolin-1 and associated kinase Fyn in integrin signaling and anchorage-dependent cell growth

Caveolin-1 functions as a membrane adaptor to link the integrin alpha subunit to the tyrosine kinase Fyn. Upon integrin ligation, Fyn is activated and binds, via its SH3 domain, to Shc. Shc is subsequently phosphorylated at tyrosine 317 and recruits Grb2. This sequence of events is necessary to couple integrins to the Ras-ERK pathway and promote cell cycle progression. These findings reveal an unexpected function of caveolin-1 and Fyn in integrin signaling and anchorage-dependent cell growth.