Biomedical subjects

G Mori

Publications and source records attributed to G Mori.

At least 19 recordsLinked to original sources

PubMed2006

Use of biomarkers to investigate toxicological effects of produced water treated with conventional and innovative methods.

The aim of this study was to develop and apply a multi-biomarker system to assess the toxicological effects of produced water (PW) from a Mediterranean off-shore oil platform. The selected bioindicator organism, mosquitofish (Gambusia affinis), was exposed in the laboratory to high concentrations of different PW: PW before treatment (BT), after conventional treatment (ACT) and after innovative treatment with zeolites in a prototype system (AIT). A set of biomarkers (benzo(alpha)pyrene monooxygenase, ethoxyresorufin-o-deethylase, vitellogenin, porphyrins, PAH bile metabolites, esterases, catalase, micronuclei) and PAH concentrations were measured in the experimental organism. The methodology proved to be appropriate and biomarker responses (CYP 1A1, PAH bile metabolites, micronuclei, esterases, porphyrins) affected by BT were less affected by ACT. PW treated with zeolites (AIT) had the lowest toxicological impact. The results obtained applying this multi-biomarker approach suggest that the system using zeolites is effective for treating produced water.

Acetylcholinesterase↗

PubMed2005

L-carnitine and isovaleryl L-carnitine fumarate positively affect human osteoblast proliferation and differentiation in vitro.

Age-related bone loss is characterized by decreased osteoblast activity, possibly related to the reduction of energy production. Carnitine promotes energy availability and its concentration declines with age; Therefore, two Carnitine derivatives, L-carnitine fumarate (LC) and isovaleryl L-carnitine fumarate (Iso-V-LC), have been tested on several parameters of human osteoblasts in vitro. Both compounds significantly increased osteoblast activity, but the new compound Iso-V-LC was more efficient than LC at lower concentrations. They both significantly enhanced cell proliferation, [3H]-proline incorporation and the expression of collagen type I (COLLI), and the bone sialoproteins (BSPs) and osteopontin (OPN). The percentage of alkaline phosphatase (ALP)-positive cells and the secretion of osteocalcin were not modified by LC and Iso-V-LC. Both molecules increased the formation of mineralized nodules, but Iso-V-LC reached the maximum effect at a concentration 10-fold lower than that of LC. Furthermore, we showed that insulin-like growth factor (IGF)-I and IGF-II mRNA levels were not modified by the treatment. However, the two compounds induced an increase of insulin-like growth factor binding protein (IGFBP)-3 and a decrease of IGFBP-5 in both osteoblast lysates and the extracellular matrix (ECM). In conclusion these data suggest that carnitine and, in particular, its new derivative, Iso-V-LC supplementation in the elderly may stimulate osteoblast activity and decrease age-related bone loss.

Alkaline Phosphatase↗

PubMed2005

T cells support osteoclastogenesis in an in vitro model derived from human periodontitis patients.

BACKGROUND: Periodontitis is characterized by alveolar bone destruction; however, the mechanisms responsible for bone damage are poorly understood. It has been reported that T cells are implicated in the pathogenesis of periodontitis. It has been also demonstrated that activated T lymphocytes secrete receptor activator of nuclear factor-kappa B ligand (RANKL) and can support the differentiation of monocytes into resorbing osteoclasts (OCs). Therefore, the purpose of this study was to examine the OC formation in periodontitis patients (PP) and the role of T cells in osteoclastogenesis. METHODS: To study OC formation, we used an in vitro model consisting of unstimulated and unfractionated peripheral blood mononuclear cells (PBMCs) from PP and controls. In parallel, T-cell-depleted PBMCs from the same patients were also established. The expression of RANKL and tumor necrosis factor-alpha (TNF-alpha) was analyzed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot in fresh T cells isolated from PP and controls. Functional antibodies, anti-RANKL and anti-TNF-alpha, were utilized to study osteoclastogenesis in PBMC cultures from PP. RESULTS: We showed that, in unfractionated PBMCs from PP, the OCs spontaneously developed in a T-cell-dependent way. The addition of macrophage colony stimulating factor (MCSF) and RANKL was necessary to promote the osteoclastogenesis in T-cell-depleted PBMC cultures from PP and in unfractionated PBMCs from periodontally healthy controls. Moreover, freshly isolated T cells from PBMCs of PP overexpressed RANKL and TNF-alpha. Finally, functional anti-RANKL and anti-TNF-alpha antibodies significantly inhibited osteoclastogenesis. CONCLUSION: Our data suggest that T cells support spontaneous osteoclastogenesis in PP via RANKL and TNF-alpha overexpression.

Adult↗

PubMed2004

Interactions of different types of localized corrosion in surgical implants.

Surgical implants often show different types of localized corrosion such as corrosion fatigue cracking, pitting and crevice corrosion on the same part. Interactions of these different corrosion phenomena were investigated. This was done by cyclic loading of electropolished tensile specimens at different constant and changing potentials. Material investigated was a surgical implant steel X2CrNiMo18-15-3 which was immersed in physiological NaCl solution. Pitting and repassivation potentials were determined. Samples with and without artificial cracks as well as masked specimens were tested. Incubation period for first damage, density and size of pits by coulometric and volumetric method were determined. The fracture surfaces were then investigated by SEM. Results show that not in all cases pitting corrosion was the cause for corrosion fatigue cracking. Also pitting is favoured by crack formation. Density of pits increases by a factor of 5 without any change to pitting potential. There are primary pits formed prior to crack initiation and secondary pits formed after crack initiation. At samples without crack there is almost no difference between the optically measured value of total pit volume and the coulometrically determined value. At samples with cracks coulometric volume of pits is much larger than optical one. This proves that there is a significant amount of crevice corrosion in the crack. The corrosion current density in the crack increases by two orders of magnitude when comparing it to electropolished surface of the sample. Results of laboratory experiments are confirmed by failure of a real implant.

Corrosion↗

PubMed2002

Rat hindlimb unloading by tail suspension reduces osteoblast differentiation, induces IL-6 secretion, and increases bone resorption in ex vivo cultures.

In this research we utilized tail-suspended rats as an in vivo model for bone loss studies in order to investigate the effects of the tail suspension on the structure of the suspended bones and in ex vivo cultures the activities of trabecular osteoblasts, marrow-derived osteogenic cells, and osteoclasts obtained from treated animals, compared with untreated controls. After a 5-day hind limb unloading, trabecular thinning was already evidenced in the tibial primary spongiosa. In the secondary spongiosa, the bone formation activity was reduced whereas osteoclastic parameters were not yet altered. Bone marrow-derived osteogenic cells and differentiated osteoblasts from enzymatic digestion of posterior limb trabecular bone were prepared from 5 day tail-suspended rats and from normally loaded rats as controls. Cell morphology, alkaline phosphatase (ALPH) activity, production of mineral matrix, osteocalcin, and IL-6 secretion were evaluated in both cell populations. Tail suspension reduced the osteogenic potential of stromal marrow cells and of already differentiated osteoblasts. In fact, ALP positive colonies were significantly reduced in number and were smaller in size compared with controls and bone nodules formed in permissive conditions were also significantly fewer and smaller, whereas in cultures of cells from control conditions, large mineralizing nodules were formed. Osteocalcin secretion was not affected by unloading. Finally, IL-6 concentration was increased in marrow-derived cells from treated rats compared with controls. Primary cultures of osteoclasts were obtained from the nonadherent fraction of the bone marrow of the same animals. The number of TRAP positive cells in culture from tail-suspended rats was significantly increased, as well as bone resorption activity, measured as resorbed surfaces of a suitable synthetic hydroxyapatite, compared with controls. These data clearly suggest that skeletal unloading not only reduces the osteogenic potential of osteoblastic cells but induces an increased osteoclastogenesis and osteoclast activity in ex vivo cultures. They also indicate for the first time that a possible mediator responsible for the increased osteoclastogenesis could be represented by the IL-6 whose secretion by bone marrow cells was significantly enhanced by unloading.

Alkaline Phosphatase↗

PubMed2001

Calixarene--poly(dithiophene)-based chemically modified electrodes.

The stepwise synthesis of cone and partial cone 1,3-bridged n-propoxy-calix[4]crown ethers ("monomers" 2 and 3) with an electropolymerizable 2,2'-dithiophene-3-yl-hexylene functionality at the lower rim, is described. The potential of 2 and 3 as sensing agents for alkali metal ions was investigated by 1H NMR titration experiments with NaSCN and KSCN. The results obtained have confirmed that the presence of the heterocyclic subunit does not affect the well-known size-selectivity observed with calix[4]crowns. Monomers 2 and 3 were electropolymerized (Pt as a working electrode, CH2Cl2/CH3CN, Bu4NPF6) to produce the title chemically modified electrodes (CMEs). After coating with a PVC membrane containing a lipophylic cation exchanger, CMEs based on calix[4]-crown-5 2b (cone) and 3b (partial cone) were tested for the potentiometric recognition of alkali metal ions in aqueous solution. In agreement with NMR titration studies, a satisfactory potentiometric response in terms of K+/Na+ selectivity was obtained only with CME 2b (pK(K/Na) 1.51). The amperometric responses of PVC-uncoated CMEs were studied by cyclic voltammetry (CV) experiments in CH3CN solution. High Na- selectivity was found with the CME based on partial cone calix[4]crown-4 3a, and frequency response analysis (FRA) measurements support this finding.

Journal Article↗

PubMed2001

Morphological analysis of knee synovial membrane biopsies from a randomized controlled clinical study comparing the effects of sodium hyaluronate (Hyalgan) and methylprednisolone acetate (Depomedrol) in osteoarthritis.

OBJECTIVE: The study was part of a randomized open-label clinical trial designed to evaluate the effects of intra-articular injections of hyaluronan (Hyalgan) (HY) in osteoarthritis (OA) of the human knee. Data were compared with those obtained after treatment with methylprednisolone acetate (Depomedrol) (MP). METHODS: Synovial membranes from patients with OA of the knee, primary or secondary to a traumatic event and classified according to the American College of Rheumatology criteria, were examined by arthroscopy and by light and electron microscopy before and 6 months after local injection of HY (2 ml of 500-730 000 MW hyaluronan, 10 mg/ml in saline, one injection per week for 5 weeks) or MP (1 ml of methylprednisolone acetate, 40 mg/ml, one injection per week for 3 weeks). RESULTS: Arthroscopy revealed a significant decrease in inflammatory score after both treatments. Histology showed that HY treatment was effective (P< or =0.05) in reducing the number and aggregation of lining synoviocytes, as well as the number and calibre of the vessels. MP treatment significantly reduced the number of mast cells in primary OA. Both treatments tended to decrease the number of hypertrophic and to increase the number of fibroblast-like lining cells, to decrease the numbers of macrophages, lymphocytes, mast cells and adipocytes, and to decrease oedema, especially in primary OA, and to increase the number of fibroblasts and the amount of collagen. These phenomena were evident throughout the thickness of the synovial tissue. CONCLUSION: At least in the medium term, both HY and MP modified a number of structural variables of the synovial membrane of the osteoarthritic human knee towards the appearance of that of normal synovium. The effect was more evident in primary OA than in OA secondary to a traumatic event. This is the first evidence that local hyaluronan injections modify the structural organization of the human knee synovium in OA.

Adjuvants, Immunologic↗

PubMed2001

Development of latent fingerprints on metallic surfaces using electropolymerization processes.

We propose a new process for developing latent fingerprints on metal items, applicable to unfired weapons made of Ergal in particular. The method is based on the presence of fatty acids that are contained in fingerprints and act as an insulator on the surface where fingerprints are to be developed. The process of polymerization occurs on the metal portions left untouched by finger contact. Hence, the developing process results as a negative pattern of the original fingerprint. The reaction consists in the electropolymerization of pyrrole and substituted porphyrins, i.e., tetra (o-aminophenyl) porphyrine: radical-cations are generated on superficial nucleation sites by oxidation of monomer, close to the electrode surface; subsequently, the radical species react with the neutral monomer, which begins to diffuse to the electrode. We have also studied the polymer's morphology by means of SEM and AFM, in order to find a correlation between the reagent to be used and the quality of the enhancement process. These are only preliminary results; however, they show that the suggested method is a new way to increase the rate of success in developing latent fingerprints on metal surfaces. In this regard, it may be considered complementary to other conventional procedures, due to the low costs of the instruments and reagents, and the rapidity and simplicity of the treatment.

Dermatoglyphics↗

PubMed2000

Expression of Fas antigen and apoptosis caused by 5,10,15, 20-tetra(4-methoxyphenyl)porphyrin (TMP) on carcinoma cells: implication for photodynamic therapy.

The photodynamic effects of 5,10,15, 20-tetra(4-methoxyphenyl)porphyrin (TMP) on a Hep-2 cell line were investigated. TMP toxicity in the dark and in relation to illumination with visible light was examined. Hep-2 cells were treated with different TMP concentrations (1, 5 and 10 microM). The uptake of TMP by Hep-2 cells increased with TMP concentration and an increase of the initial uptake rate was observed with increasing TMP concentrations. However, after 24 h of incubation, a similar value of intracellular TMP concentration was reached at all three concentrations of TMP added. Cell toxicity induced by TMP was analyzed in the dark at different concentrations of the photosensitizer and at several incubation periods. The cell mortality obtained after exposure of the cell cultures to visible light was exclusively due to the photosensitization effect of TMP produced by light irradiation. Staining with the hematoxylin-eosin method demonstrated that treatment with TMP, followed by exposure to visible light, notably increased the apoptotic figures. Fas antigen was only expressed in these conditions. The results contribute to the understanding of the photodynamic therapy (PDT) mechanism produced by TMP on Hep-2 carcinoma cell line.

Apoptosis↗

PubMed2000

Breast cancer cell line MDA-231 stimulates osteoclastogenesis and bone resorption in human osteoclasts.

Breast cancers commonly cause osteolytic metastases in bone, a process that is dependent upon osteoclast-mediated bone resorption, but the mechanism responsible for tumor-mediated osteoclast activation has not yet been clarified. In the present study we utilized a well-known human breast cancer cell line (MDA-231) in order to assess its capability to influence osteoclastogenesis in human bone marrow cultures and bone resorption in fully differentiated osteoclasts. We demonstrated that conditioned medium (CM) harvested from MDA-231 increased the formation of multinucleated TRAP-positive cells in bone marrow cultures. Bone resorption activity of fully differentiated human osteoclasts and of osteoclast-like cell lines, from giant cell tumors of bone (GCT), was highly increased by the presence of MDA-231 CM. Moreover, while MDA-231 by themselves did not produce IL-6 tumor cell, CM increased the secretion of IL-6 by primary human osteoclasts and GCT cell lines compared to untreated controls. These data suggest that MDA-231 produce osteoclastic activating factor(s) that increase both osteoclast formation in bone marrow culture and bone resorption activity by mature cells. Moreover, breast cancer cells stimulate IL-6 secretion by osteoclasts that is one of the factors known to supports osteoclastogenesis.

Acid Phosphatase↗

PubMed2000

Effects of alpha-difluoromethylornithine on the cyclin A expression in Hep-2 cells.

DFMO is an irreversible inhibitor of ornithine decarboxilase (ODC), the key enzyme in mammalian polyamine biosynthesis. The goal of this study was to determine the effects of DFMO on the expression of cyclin A at different stages of the cell cycle of Hep-2 cells. The cell cycle analysis, done by measuring the incorporation of thymidine in the cell DNA, revealed that DFMO produced a lower and constant level of that incorporation; this effect is probably due to the incapacity of the cells to culminate the phase S of the cell cycle. The expression of cyclin A increased in the phases S and G2 in control cells, almost disappearing in phase M. However, in DFMO treated cultures, the expression of cyclin A was increased in M and this effect remained still after 48 h treatment. We conclude that polyamines could exert an effect on the cyclin destruction mechanism, and the depletion caused by DFMO would alter this mechanism.

Cyclin A↗

PubMed2000

Effects of alpha-difluoromethylornithine on the Fas expression and apoptosis in Hep-2 cells.

DFMO is an irreversible inhibitor of ornithine decarboxilase (ODC), the key enzyme in mammalian polyamine biosynthesis, and has been shown to induce apoptosis. In this paper, the relation between the effects of DFMO on the polyamine content, apoptotic index and Fas expression in HEP-2 cells was determined. Fas is a type I membrane protein with a molecular mass of 45 kDa, which mediates apoptosis. The results suggest that the treatment with the polyamine inhibitor DFMO induced the expression of the surface antigen Fas, which could be responsible for trigger apoptosis in these cells.

Apoptosis↗

PubMed1999

Hyaluronic acid by atomic force microscopy.

Hyaluronic acid (HA) of different molecular weights has been examined by atomic force microscopy (AFM) in air. This technique allows 3-D surface images of soft samples without any pretreatment, such as shadowing or staining. In the present study we examined the supermolecular organization of HA chains when deposited on mica and graphite, to better understand the interchain and intrachain interactions of HA molecules in solution. The concentration of the solution deposited varied from 0.001 to 1 mg/ml. On both substrates, and independent of the concentration, high-molecular-mass HA formed networks in which molecules ran parallel for hundreds of nanometers, giving rise to flat sheets and tubular structures that separate and rejoin into similar neighboring aggregates. Accurate measurements of the thickness of the thinnest sheets were consistent with a monolayer of HA molecules, 0.3 nm thick, strongly indicating lateral aggregation forces between chains as well as rather strong hydrophilic interactions between mica and HA. The results agree with an existing model of HA tertiary structure in solution in which the network is stabilized by both hydrophilic and hydrophobic interactions. Our images support this model and indicate that hydrophobic interactions between chains may exert a pivotal role in aqueous solution.

Aluminum Silicates↗

PubMed1999

Terminal end of the human odontoblast process: a study using SEM and confocal microscopy.

Towards the middle of the eighteenth century, Tomes described the presence of membranous structures of cellular origin inside the dentinal tubules. Subsequent studies have been controversial regarding the terminal end of the odontoblasts. According to Fusayama, this cellular process reaches even the dentinal-enamel junction; others, such as Brännström, believed that this cellular process is present only in the inner third of the dentin. The aim of the present study was to determine the exact area up to which the terminal ends of the odontoblasts extend. With the aid of advanced confocal laser scanning microscopy (CLSM) cylindrical structures were demonstrated inside the tubules even in the absence of odontoblasts. This would confirm that the structures previously described as cellular processes can be identified with the lamina limitans of the peritubular dentin. High resolution field-emission scanning electron microscopy (FE-SEM) provided further evidence that tubular structures are only seen in the inner third of the dentin, towards the pulp.

Adult↗

PubMed1999

[Polishing of composite resins. Instrumental notes].

BACKGROUND: The polishing is the last procedure in the application of composite fillings. The surface morphology and the marginal seal, that are indispensable for integration of composite fillings with dental tissue and oral environment, are tightly dependent on polishing procedure. METHODS: The authors tried out experimental therapeutic procedure in order to examine the surface of any composite resin polymerizated under matrix on a slide before and after polishing made by abrasive disease and finally after application of a new resin layer on a polished composite surface. These composite surfaces was examined with AFM and SEM. RESULTS: The images prove that in the polished specimens there is a restoration of composite morphology surface because of the partial removal of organic part during the polishing. The polymerization of a new resin layer on polished surface make this one more regular and even as a substitute for partial removal of organic part during the polishing. CONCLUSIONS: The experimental procedure prove that the ideal composite surface is that polymerizated under matrix because every treatment on this surface affect the composite filling's quality.

Composite Resins↗

PubMed1999

Esthetic and functional reproduction of occlusal morphology with composite resins.

The increasing use of composite resin restorations in posterior sectors produces some difficulties in the exact reproduction of occlusal morphology. In this article we present a new operative method that allows a quick and precise reproduction of occlusal morphology with minimal carious destruction of the occlusal enamel of posterior dental elements in the case of initial carious lesions. This method is indicated for class I and II carious lesions and is based on a preoperative record of the occlusal morphology made with a transparent silicone mold. This mold is placed on the tooth after the application of the last layer of composite resin, which is then polymerized through the silicone. Illustrated as a clinical case, the method is particularly rapid, easy to perform, and contributes to the improved quality and subsequent success of composite restorations in posterior sectors.

Adult↗

PubMed1999

Apoptosis is regulated by polyamines in the cell cycle of Chinese hamster ovary cells.

This paper deals with the relationship between the polyamine metabolism and apoptosis in the different phases of the cell cycle in a Chinese hamster ovary (CHO) cell line. Synchronously growing cells were obtained by the addition of 1.2 mM hydroxyurea and the progression through the cell cycle was monitored by determining the incorporation of 3H-thymidine in the DNA. Ornithine decarboxylase (ODC) activity showed a peak in S phase, while intracellular putrescine and spermine contents increased constantly, reaching to a maximum level at G2 phase; spermidine content doubled during G2 and increased four times during M, compared to G1. The increment in the endogenous polyamine content was associated to a diminished uptake from the medium. The apoptotic index was higher in G2 phase, coinciding with the maximum level observed in putrescine content. The results support the idea that intracellular putrescine level is closely related to apoptosis.

Animals↗

PubMed1998

Alendronate reduces adhesion of human osteoclast-like cells to bone and bone protein-coated surfaces.

Bisphosphonates (BPs) are potent inhibitors of bone resorption and are therapeutically effective in disease of increased bone turnover, but their mechanism(s) of action remain to be elucidated. Using as experimental model human osteoclast-like cell lines derived from giant cell tumors of bone, extensively characterized for their osteoclast features, we investigated the adhesive properties of osteoclasts on bone slices and on different proteins of the extracellular matrix in the presence of BPs. Adhesion assays using bone slices pretreated with ALN, at the established active concentration, showed that, although the morphology of osteoclasts plated onto pretreated bone slices was not modified, the number of adherent cells was reduced by the treatment of about 50% vs. controls. The effect of ALN on the adhesion of osteoclast-like cells onto specific extracellular matrix proteins, such as bone sialoprotein-derived peptide, containing the RGD sequence, conjugated to BSA (BSP-BSA) and fibronectin (FN), was also tested. In the case of FN the treatment with ALN of protein-coated wells did not modify the percentage of cell adhesion compared with the control, whereas onto BSP-BSA the presence of ALN significantly reduced adhesion of about 40-45%, suggesting that the inhibitory effect of ALN on cell adhesion could probably be due to the interference with receptors specifically recognizing bone matrix proteins as alphaVbeta3 integrins. Furthermore, ALN induced Ca-mediated intracellular signals in osteoclasts, triggering a 2-fold increase in intracellular calcium concentration.

Alendronate↗