Search PubMed⌕ Search

Biomedical subjects

M Marotta

Publications and source records attributed to M Marotta.

At least 19 recordsLinked to original sources
PubMed2001

Adenovirus-mediated wt-p16 reintroduction induces cell cycle arrest or apoptosis in pancreatic cancer.

Pancreatic cancer has long carried poor prognosis. The development of new therapeutic approaches is particularly urgent. Inactivation of the tumor-suppressor gene p16(INK4a/CDKN2), a specific inhibitor of the cyclin-dependent kinases CDK4 and CDK6, is the most common genetic alteration in human pancreatic cancer, making it an ideal target for gene replacement. Here we transfected tumor cells using a recombinant adenovirus containing the wt-p16 cDNA (Ad5RSV-p16). The overexpression of p16 decreased cell proliferation in all four human pancreatic tumor cell lines (NP-9, NP-18, NP-29, and NP-31). However, G1 arrest and senescence were observed in only three. In contrast, the fourth (NP-18) showed a significant increase in apoptosis. This differential behavior may be related to the differences found in the expression level of E2F-1. Experiments on subcutaneous pancreatic xenografts demonstrated the effectiveness of p16 in the inhibition of pancreatic tumor growth in vivo. Taken together, our results indicate that approaches involving p16 replacement are promising in pancreatic cancer treatment.

Adenocarcinoma↗
PubMed2001

DAG accumulation from saturated fatty acids desensitizes insulin stimulation of glucose uptake in muscle cells.

The increased availability of saturated lipids has been correlated with development of insulin resistance, although the basis for this impairment is not defined. This work examined the interaction of saturated and unsaturated fatty acids (FA) with insulin stimulation of glucose uptake and its relation to the FA incorporation into different lipid pools in cultured human muscle. It is shown that basal or insulin-stimulated 2-deoxyglucose uptake was unaltered in cells preincubated with oleate, whereas basal glucose uptake was increased and insulin response was impaired in palmitate- and stearate-loaded cells. Analysis of the incorporation of FA into different lipid pools showed that palmitate, stearate, and oleate were similarly incorporated into phospholipids (PL) and did not modify the FA profile. In contrast, differences were observed in the total incorporation of FA into triacylglycerides (TAG): unsaturated FA were readily diverted toward TAG, whereas saturated FA could accumulate as diacylglycerol (DAG). Treatment with palmitate increased the activity of membrane-associated protein kinase C, whereas oleate had no effect. Mixture of palmitate with oleate diverted the saturated FA toward TAG and abolished its effect on glucose uptake. In conclusion, our data indicate that saturated FA-promoted changes in basal glucose uptake and insulin response were not correlated to a modification of the FA profile in PL or TAG accumulation. In contrast, these changes were related to saturated FA being accumulated as DAG and activating protein kinase C. Therefore, our results suggest that accumulation of DAG may be a molecular link between an increased availability of saturated FA and the induction of insulin resistance.

Acetates↗
PubMed2000

Changes in myocardial cytoskeletal intermediate filaments and myocyte contractile dysfunction in dilated cardiomyopathy: an in vivo study in humans.

AIM: To investigate in vivo the intermediate cytoskeletal filaments desmin and vimentin in myocardial tissues from patients with dilated cardiomyopathy, and to determine whether alterations in these proteins are associated with impaired contractility. METHODS: Endomyocardial biopsies were performed in 12 patients with dilated cardiomyopathy and in 12 controls (six women with breast cancer before anthracycline chemotherapy and six male donors for heart transplantation). Biopsy specimens were analysed by light microscopy and immunochemistry (desmin, vimentin). Myocyte contractile protein function was evaluated by the actin-myosin in vitro motility assay. Left ventricular ejection fraction was assessed by echocardiography and radionuclide ventriculography. RESULTS: Patients with dilated cardiomyopathy had a greater cardiomyocyte diameter than controls (p < 0.01). The increase in cell size was associated with a reduction in contractile function, as assessed by actin-myosin motility (r = -0.643; p < 0.01). Quantitative immunochemistry showed increased desmin and vimentin contents (p < 0.01), and the desmin distribution was disturbed in cardiomyopathy. There was a linear relation between desmin distribution and actin-myosin sliding in vitro (r = 0.853; p < 0.01) and an inverse correlation between desmin content and ejection fraction (r = -0.773; p < 0.02). Negative correlations were also found between myocardial vimentin content and the actin-myosin sliding rate (r = -0.74; p < 0.02) and left ventricular ejection fraction (r = -0.68; p < 0.01). CONCLUSIONS: Compared with normal individuals, the myocardial tissue of patients with dilated cardiomyopathy shows alterations of cytoskeletal intermediate filament distribution and content associated with reduced myocyte contraction.

Actins↗
PubMed1998

The quality control and stability testing of homeopathic preparations.

Homeopathic medicines are known and have been used traditionally in Europe for many centuries. The preparation of the medicines is based on the medicines is based on the experiments of individual homeopathists instead of industry scale. Moreover, limited literature is available and the analytical methods used for the analysis of homeopathic raw materials are not by means of high tech analyses. In order to achieve high quality homeopathic products, our laboratory has developed, as well as, improved the analytical techniques for the homeopathic raw materials using TLC, HPLC and titration methods. Examples being: a) TLC method for Ambra grisea (1) b) HPLC method for Harpagophytum procumbens O = D1 (2) c) Titration method for Ostrea edulis D1 (3) The stability test of homeopathic products is based on its chemical, physical and microbiological stability. Results of these assays will be presented.

Chromatography, High Pressure Liquid↗
PubMed1997

A family of centromeric satellite DNAs from the European brown frog Rana graeca italica.

Digestion of Rana graeca italica DNA with Asp 718I produces highly repetitive fragments of 281 and 385 bp that were cloned and sequenced. The shorter fragment corresponds to the unit repeat (RgiS1b) of a satellite DNA. The longer fragment was found to be part of a 494-bp repeat of another satellite DNA (RgiS1a) that was cloned intact as an EcoRV fragment. RgiS1b is 97% homologous to RgiS1a, from which it seems to be derived by a single deletion. Among all species tested, only the related brown frog Rana dalmatina contained homologous repetitive DNA. The overall number of RgiS1a and RgiS1b repeats per R. graeca italica haploid genome was estimated to be 2.7 x 10(5). RgiS1a and RgiS1b repeats are organized in separate arrays, but repetitive units formed by various combinations of the two repeats were also observed on Southern blots. The amount of these extra repeats varies greatly among animals from the same population, representing a rare case of individual variability in the satellite DNA organization. FISH with probes specific for both satellites, or for RgiS1a only, labeled the centromeric and pericentromeric heterochromatin of all chromosomes. This indicated that RgiS1a and RgiS1b are interspersed within the same heterochromatic regions of the chromosomes.

Animals↗
PubMed1994

Amino acid composition of two peptides purified from mitochondrial calf liver DNA.

In this research the amino acidic composition of a peptide fraction from mitochondrial DNA has been determined, using HPLC and the fingerprinting technique. This peptide fraction has been shown to be composed of two sub-fractions with different reactivity to ninhydrin, and thus supplied with several N-substitute groups. The composition of the first fraction is Gln, Glu, Pro, Leu. The second fraction composition is Pro, Glu or Gln, Asp or Asn, Ser.

Amino Acid Sequence↗
PubMed1993

Effect of a peptide fraction extracted from mitochondrial DNA on rat liver cell viability.

The authors verified the effect of a peptidic fraction from mitochondrial DNA on liver cell cultures. Primary cultures treated with the mitochondrial peptidic fraction (final concentration 0.025 O.D./ml) showed a higher viability after 48 hours with respect to cultures without mitochondrial peptidic fraction (p < 0.05). The results indicate a probable action of the mitochondrial peptidic fraction on liver cell viability.

Animals↗
PubMed1993

Thermal analysis of rat bone tissue.

The paper describes thermoanalytical data obtained from rat limb bones by TG, DTG and DSC. Analyses were performed on bone samples from femurs, tibiae and humeri, either crude and extracted with acetone and/or sodium dodecylsulphate. The DSC curves show an endothermic reaction at 85 degrees C and a sharp exothermic peak at 337 degrees C, followed by an exothermic profile between 350 degrees-650 degrees C. Mean weight changes are: 34.28% total weight loss (25 degrees-800 degrees C); 7.33% water loss (25 degrees-200 degrees C); 26.21% organic loss (200 degrees-800 degrees C). Thermal analysis on diaphyseal and epiphyseal bone samples evidences an organic content of 24.54% for diaphyseal compact bone tissue and of 30.62% for epiphyseal trabecular bone tissue (p < .005). The values obtained from different bones and by different treatment of samples are compared.

Animals↗
PubMed1992

Perceptions of emergency care by the elderly: results of multicenter focus group interviews.

STUDY OBJECTIVE: To determine the elderly's perception of emergency care and to identify specific problems and solutions. DESIGN: Focus group interviews. SETTING AND TYPE OF PARTICIPANTS: Community senior citizen centers in Boston; Los Angeles; Pittsburgh; Youngstown, Ohio; and Norwalk, Connecticut. Senior citizens who had had emergency care in the past year participated. MEASUREMENT AND RESULTS: Participants were satisfied with their overall medical care. Long waits were a hardship for patients and their families. The elderly are not familiar with the process of emergency care. They were frightened by their injury or illness. Their anxiety was not allayed until they were informed of the nature of their illness and what their treatment and disposition was to be. The emergency department environment frequently made them uncomfortable. There was considerable confusion caused by the billing process. CONCLUSIONS: The elderly would benefit from prior or concurrent education regarding emergency care. Staff should be more sensitive to the anxiety felt by the elderly, should explain the reasons for delays in care, and what to expect. Patients should be informed of the nature and seriousness of their illness as soon as possible. Family and friends may be encouraged to stay with patients. The billing process needs to be clarified and simplified.

Aged↗
PubMed1992

Effect of thyroid hormones and their analogues on the mitochondrial calcium transport activity.

In this paper the authors studied the effects of thyroid hormones and their structural analogues on the mitochondrial calcium transport activities. The thyroid hormones, 3,5,3' L-triiodothyronine (LT3) and 3,5,3'5' L-tetraiodothyronine (LT4) at physiological intracellular concentrations between 7.2 and 9 nM, decouple total Ca++ transport, as well as inhibit the passive transport of Ca++, either due to oxidation of pyruvate, malate or succinate or after inhibition with rotenone. The optical isomers 3,5,3' D-triiodothyronine (DT3) and 3,5,3',5' D-tetraiodothyronine (DT4) are less effective at all the used concentrations. Furthermore the structural analogues 3,3',5' L-triiodothyronine (LrT3), 3,5-dicloro, 3',5' L-diiodothyronine (LDiClT2) and 3,5 L-diiodothyronine (LT2) furnished even less effects on the same activities. The effect of the thyroid hormones and of their structural analogues has revealed that the mitochondrial calcium transport may be influenced both by a stereospecific interaction between hormones and protein ligands and by a lipophilic chaotropic action on the mitochondrial membranes lipids. In this context it is interesting to consider that both thyroid hormones and Ca++ transport activity are interacting with the energetic metabolism by means of phosphorylation and substrate oxidation mechanism.

Animals↗
PubMed1992

The extracellular matrix in slow-growing tumors of the central nervous system.

This report describes and illustrates the results of the histopathological and histochemical investigation on five slow-growing tumors of the central nervous system: four meningiomas and an ependymoma of the spinal cord. We have studied, by means of polarizing microscopy, sections stained with picro-sirius red F3BA that enhance the birefringence of collagen and reticulum fibres. The heterogeneous behaviour of the distribution of the collagen let us conclude that the fibrillar component of the extracellular matrix have a scarce importance for the speed of growth of these tumours.

Cell Division↗
PubMed1985

Sensitive spectrophotometric method for the quantitative estimation of collagen.

A method to estimate collagen concentration is described. It is based on the ability of the dye Sirius Red F3BA to quantitatively precipitate collagen in acetic acid solution. Collagen content is determined by evaluating spectrophotometrically the absorbance decrease of a Sirius Red/acetic acid solution. The assay can be used in the range from 1 to 50 micrograms protein. The method is specific, sensitive, simple, and rapid.

Acetates↗
PubMed1985

Glycosaminoglycans in human breast cancer: morphological and biochemical study.

The authors evaluate the distribution and the content of glycosaminoglycans (GAG) in neoplastic tissue from mastectomy specimens of 15 patients treated for an infiltrating ductal carcinoma NOS, in comparison to normal tissue of the opposite quadrant. Neoplastic tissues contain a marked amount (5 mg/g dry defatted tissue) of GAG, in comparison to normal ones (2.2 mg/g dry defatted weight). In stellate carcinomas GAG are localized near the interface with the host tissue and are constituted mainly of chondroitin sulfates and hyaluronate. These data are confirmed by electrophoretic analysis.

Alcian Blue↗
PubMed1985

Collagen in human breast cancer: morphological and biochemical study.

The authors studied the distribution and the composition of collagen in neoplastic tissue from mastectomy specimens of 15 patients treated for an infiltrating ductal carcinoma NOS, in comparison to normal tissue of the opposite quadrant. The study was performed by light microscopy, microspectrophotometry, and electrophoretic methods. The results demonstrate a characteristic stromal organization of breast cancer in relation to collagen type I content.

Breast↗
PubMed1985

Sacrococcygeal chordoma: histochemical findings.

Two cases of chordoma of the sacrococcygeal region have been histochemically evaluated. In both cases an irregularly shaped stellate cell, containing large amounts of glycogen, is the prevailing cell type. Neoplastic cells interact with an extracellular matrix consisting of a collagenous framework and a heterogeneous family of glycosaminoglycans with a prevalence of chondroitin sulfate chains and, to a smaller extent, of hyaluronate molecules. We emphasize the value of these data in order to differentiate this tumor from other sacrococcygeal neoplastic lesions.

Adult↗
PubMed1984

[Ultrastructure of human cerebral neoplasms in vitro: glioma].

The authors describe the in vitro structural features of cellular populations derived from human gliomas. They report the structure of each population, and hypothesize on the correlation among these different cell populations. The findings of this study show some of the individual glioma cell lines to have characteristic structures.

Brain Neoplasms↗