Search PubMed⌕ Search

Biomedical subjects

M Marini

Publications and source records attributed to M Marini.

At least 181 records · Page 10Linked to original sources
PubMed1987

[Macroamylasemia or pancreatitis? A diagnostic problem].

Macroamylasemia is a condition characterized by a serum amylase activity increase due to complex macromolecules whose large size prevents its urinary excretion. It cannot be consistently correlated with any particular disease state, and should be regarded as a benign chemical derangement. The major clinical importance of macroamylasemia is the confusion of this condition with other causes of hyperamylasemia and its prevalence in the population, comprised between 1 and 2%. Macroamylasemia should be considered in any patient with elevated levels of serum amylase activity whose serum lipase and urine amylase levels are normal, in the face of unimpaired renal function. Confirmation rests on the demonstration of a macromolecular amylase component in the serum by means of chromatography, ultracentrifugation and electrophoresis. In this report, we, describe a patient with chronic liver disease caused by alcohol, occasional abdominal pain and persistent hyperamylasemia, though to be due to pancreatitis, but subsequently shown to be due to a macroamylase.

Amylases↗
PubMed1987

Effect of vanadate of PHA-induced proliferation of human lymphocytes from young and old subjects.

The effect of sodium orthovanadate on mitogen-induced proliferation of lymphocytes from young and old human subjects is reported. We found that vanadate is not mitogenic per se; it has an inhibitory effect during the first 3 days of culture, when both differentiation and proliferation take place; it enhances DNA synthesis, acting as a co-mitogen, in the following days of culture, when proliferation prevails. In spite of the fact that lymphocytes from the two groups differ in their responsiveness to PHA and in the activity of (Na+,K+)ATPase, no difference was found as for the effects of vanadate.

Adolescent↗
PubMed1987

Isoelectric focusing on cellulose acetate membrane: a separation procedure for alkaline phosphatase isoenzymes.

An isoelectric focusing technique for the separation of alkaline phosphatase isoenzymes on cellulose acetate membrane is described. Optimal conditions for isoelectric focusing were established by changing ampholine concentration and focusing conditions. Bone, liver, intestinal, and placental isoenzymes can be resolved into various sub-bands in a pH range of 4.1 to 5.2. These sub-bands were correlated with the findings of electrophoretic isoenzyme separation. The whole procedure proves very simple to perform and comparatively time saving (4 h). This procedure may help clarify the problems of ALP isoenzyme differentiation when electrophoretic patterns are unresolved.

Adolescent↗
PubMed1987

Human T-lymphocyte-derived megakaryocyte colony-stimulating activity.

Conditioned medium from a T-lymphoblastic cell line (Mo) contains a number of well-characterized hemopoietins. In this paper we demonstrate that Mo cells also release a factor(s) able to stimulate the growth and the differentiation of megakaryocytic progenitors into large-size pure megakaryocytic colonies in plasma clot cultures. Comparison with other sources of human-active hemopoietins shows that Mo-conditioned medium performs better than others, especially for the megakaryocytic lineage. The factor(s) shows strong similarities with human Meg-CSF obtained from a thrombocytopenic patient's plasma, and is distinguishable from the other hemopoietins present in the medium.

Bone Marrow Cells↗
PubMed1986

D-ribose inhibits DNA repair synthesis in human lymphocytes.

D-ribose is cytotoxic for quiescent human lymphocytes and severely inhibits their PHA-induced proliferation at concentrations (25-50 mM) at which other simple sugars are ineffective. In order to explain these effects, DNA repair synthesis was evaluated in PHA-stimulated human lymphocytes treated with hydroxyurea and irradiated. D-ribose, in contrast to other reducing sugars, did not induce repair synthesis and therefore did not apparently damage DNA in a direct way, although it markedly inhibited gamma ray-induced repair. Taking into account that lymphocytes must rejoin physiologically-formed DNA strand breaks in order to enter the cell cycle, we suggest that D-ribose exerts its cytotoxic activity by interfering with metabolic pathways critical for the repair of DNA breaks.

Arabinose↗
PubMed1985

An automated differential thermal and potentiometric titration apparatus for binding studies.

A differential pH-thermal titration apparatus is described which can detect pH differences with a sensitivity of +/- 0.0001 pH units and a thermal sensitivity of +/- 0.00002 degree C at a time constant of 0.1 s. With a reaction which yields 1 kcal mol-1, the current system can detect concentrations as low as 4 X 10(-6) M or, in a 2 ml volume, a total amount of 40 nmol. With a time constant of 0.1 s, the sensitivity is 20 +/- 4 micro degrees C. The experimental protocol is specified by a microprocessor and three modes of operation are possible: titration at constant rate of reagent addition, titration at variable rates of addition so that the contents of both cells are at either constant pH or at a constant temperature and variable rate when a rate of change is specified. Experimental data are collected in files, corrected for heat loss, initial baseline drift, and changes in volume. The final corrected data from the standardized run of 0.01338 M HCl in 0.2 M KCl at 25 degrees C calibrate the pH scale and yield the calorimetric conversion constants and pKw which are calculated and stored for subsequent corrections for the titration of an unknown acid or the measurement of binding constants and heats.

Calorimetry↗
PubMed1985

Inhibition of cell proliferation by D-ribose and deoxy-D-ribose.

D-Ribose and deoxy-D-ribose inhibited DNA, RNA, and protein synthesis in a wide variety of cells (dividing and nondividing, normal and neoplastic, freely floating and substrate adhering, human and murine) at concentrations at which other monosaccharides have little or no effect. Inhibition was irreversible and proportional to the sugar concentration and time of contact. However, the first effects were seen only after 24 hr of incubation and progressed slowly to cell death. Whether the two sugars share the same mechanisms of action is not known. In any case, they deeply disturb metabolic processes in both dividing and nondividing cells.

Animals↗
PubMed1984

Megakaryocytopoiesis in bone marrow-derived stromal-hemopoietic cells co-cultures: action of Tamm-Horsfall glycoprotein.

Murine bone marrow cells are cultured in agar in the presence of marrow-derived fibroblasts and pokeweed-stimulated spleen conditioned medium. Granulo-monocytic colonies and a few megakaryocytic and mixed colonies are induced. The addition of Tamm-Horsfall glycoprotein - a human glycoprotein produced in the kidneys - increases the number of colonies and stimulates megakaryocytopoiesis. The glycoprotein does not have colony-stimulating activity nor does it induce megakaryocytopoiesis in monolayer cultures. Its major glycopeptide retains the ability to increase the number of colonies, but not to induce megakaryocytopoiesis. Cell-cell interactions occurring in the hemopoietic microenvironment and the effect of glucides are discussed.

Acetylcholinesterase↗
PubMed1984

Ultrastructural features of supramedullary neurons in Crenilabrus quinquemaculatus.

The ultrastructural study of the supramedullary neurons in Crenilabrus quinquemaculatus shows that these cells are engaged in intense synthetic activity as is testified by the nuclear morphology, the plentiful rough endoplasmic reticulum and polysomes, and finally the remarkably developed Golgi complexes, many of them active. Moreover the cytoplasm of the supramedullary neurons shows numerous membrane-bounded bodies (1,800-4,000 A) containing electron dense material, more or less finely granular. Research is presently being carried out to establish the meaning of these electron dense bodies.

Animals↗
PubMed1983

Tumor-specific tRNA modifications in mouse plasmacytomas and other tumors.

RPC-5 chromatography has been used to analyze the aa-tRNA populations found in normal organs and in various tumors in experimental animals. The most extensively studied animal systems have been mineral-oil-induced mouse plasmacytomas and carcinogen-induced rat hepatomas. Certain aa-tRNA species appear to be tumor-specific, e.g., rat hepatoma phenylalanyl-tRNA1 and plasmacytoma asparaginyl-tRNAs2-4. In addition, one of the tumor-specific peaks of asparaginyl-tRNA can be found in normal livers of animals bearing plasmacytomas at a distant site. Many other significant quantitative and qualitative differences among histologically similar plasmacytomas and between normal tissues and plasmacytomas were observed in the chromatographic patterns of isoaccepting aa-tRNAs for 11 of 20 amino acids. Some of the qualitative differences in chromatographic patterns could be correlated with the tumorous nature of the tissue using computer analysis. The program utilized cluster analysis to compare the RPC-5 patterns of aa-tRNAs from 11 plasmacytomas and two normal tissues for each of the 20 amino acids. The variations in these chromatographic profiles are though to be caused by varying degrees of incomplete synthesis of some of the normally modified nucleosides in tRNAs.

Amino Acid Sequence↗
PubMed1982

TdT-positive and TdT-negative human leukemic cells: specific density and morphology.

Peripheral blood cells from 9 E- and 6 D+ SIg- ALL patients and from 11 CML patients in TdT+ blastic crisis were subjected to discontinuous albumin gradient separation according to Dicke's method, and TdT assayed in the six fractions recovered therefrom. The major results were: (i) in E- ALL and in CML-BC, TdT+ cells could be recovered either within a narrow range of specific densities or were spread over most of the gradient, which might suggest differences in cell maturation among the patients; (ii) in some instances, most leukemic blasts were found in TdT-negative or faintly positive fractions; (iii) in most, but not all, E- All and BC, the majority of TdT+ cells was found in low density fractions; (iv) all E+ ALL had high density TdT+ cells. Cell Fractions of most patients were also examined at the electron microscope, and correlations between morphology and marker characterization were tentatively drawn.

Cell Separation↗
PubMed1982

Effect of pollution on some freshwater species. I. histochemical and biochemical features of lead pollution on some organs of Viviparus viviparus L. (Mollusca Gastropoda).

Experimental lead pollution was studied in some organs (foot, mantle and digestive gland) of Viviparus viviparus L. The amount of lead contained after 48h, 96 h and one week of pollution were established using an atomic absorption spectrophotometer. On the basis of physicochemical determination, it turns out that lead is mainly concentrated in the mantle. The biochemical tests (cholesterol, sulpholipids and phospholipids) were aimed at evaluating the lipids involved in the membranes. The histochemical research was carried out chiefly to evaluate the modifications of polysaccharides and proteins. Some hydrolytic enzymes (Na+ and K+ dependent ATPase) and some ooreductive enzymes (NADH+ and NADPH+ dependent diaphorases, D-lactate dehydrogenase, succinate dehydrogenase and glucose-6-P-dehydrogenase) were also tested. The digestive gland is the most severely damaged organ as proved by histomorphological and biochemical analyses.

Animals↗