PubMed Health⌕ Search

Biomedical subjects

M Marchisio

Publications and source records attributed to M Marchisio.

At least 37 records · Page 2Linked to original sources
PubMed1997

Changes of nuclear PI-PLC gamma1 during rat liver regeneration.

We have previously demonstrated that rat liver nuclei contain PI-PLC beta1 and gamma1 in the inner nuclear matrix and lamina associated with specific phosphodiesterase activity (Bertagnolo et al., 1995, Cell Signall. 7, 669-678). Since compensatory hepatic growth is an informative and well characterized model for natural cell proliferation, the presence of specific PI-PLC isoforms and their activity as well as PIP2 recovery were studied at various regenerating times, ranging from 3 to 22 h after partial hepatectomy. Three PI-PLC isoforms (beta1, gamma1, delta1) were examined in control and regenerating liver cells by using specific antibodies. By means of in situ immunocytochemistry and confocal microscopy, PI-PLC beta1 was found mainly in the nucleoplasm and this pattern was not modified after hepatectomy. On the contrary, the nuclear gamma1 isoform showed a marked decrease at 3 and 16 h after hepatectomy, but a clear increase at 22 h covering with bright intensity the whole nucleus. The PI-PLC delta1 isoform, which is exclusively cytoplasmic, was not altered during rat liver regeneration. By western blotting analysis on whole cell homogenates, none of the PI-PLC isozymes under study showed proliferation-linked modification. However, analyses of isolated nuclei identified changes in the nucleus associated PI-PLC gamma1 that paralleled the in situ observation whereas the beta1 isoform was unmodified at all the times examined. Nuclear phosphodiesterase activity on PIP2 was lower at 3 and 16 h, in comparison with sham operated rats, increased at 6 h and reached the highest value after 22 h. Consistently, the recovery of PIP2, obtained in conditions that optimise PIP-kinase activity, showed a marked decrease at 3 h and an increase up to 16 h of liver regeneration, followed by a further decrease at 22 h. These data are consistent with a close relationship between cell proliferation and the nuclear inositide cycle, depending, in rat liver, predominantly on the modulation of the gamma1 isoform of PI-PLC.

Animals↗
PubMed1996

Changes of nuclear protein kinase C activity and isotype composition in PC12 cell proliferation and differentiation.

To establish whether protein kinase C was involved in the nuclear events underlying cell differentiation and proliferation, rat pheochromocytoma PC12 cells, serum-starved for 24 h, were treated with either differentiating doses of nerve growth factor or high serum concentrations, which represented a powerful mitogenic stimulus. Western blot analysis with isoform-specific antibodies, performed on whole cell homogenates, cytoplasms, and purified nuclei, showed that PKC isotypes alpha, beta I, beta II, delta, epsilon, eta, and zeta were expressed in PC12 cells and that all of them, except for beta I, were found at the nuclear level, variably modulated depending on the cell treatment. Compared to serum-stimulated cells, in which an early (1 day) and marked rise of protein kinase C activity was followed by a plateau, nerve growth factor-treated cells showed a progressive increase of protein kinase C activity coincident with the onset and maintenance of the differentiated phenotype. Western blot analysis of nuclei isolated from fully differentiated cells demonstrated an increase of protein kinase C alpha, paralleled by enhanced phosphotransferase activity along with the nerve growth factor treatment, and complete loss of the delta isotype. In contrast, in nuclei of proliferating PC12 cells, after an early but modest increase at 1 day of mitogenic stimulation, protein kinase C activity reached a plateau. Isotype-specific analysis indicated a concomitant increase of protein kinase C beta II, delta, and zeta and the appearance of protein kinase C epsilon and eta at the nuclear level. Considering the relative intensity of the cytoplasmic and nuclear immunoreactive bands under the three conditions examined, clear-cut translocation to the nucleus occurred for PKC epsilon and eta in serum-stimulated cells. Additional nuclear accumulation of PKC by translocation from the cytoplasm was prominently induced for the zeta isoform after mitogenic stimulation and for PKC alpha during prolonged NGF treatment. Our data suggest that nuclear translocation and selective activation of distinct protein kinase C isoforms play a relevant role in the control of proliferation and differentiation of the same cell type and that nuclear protein kinase C is crucial to the induction and persistence of the differentiated neuronal phenotype of PC12 cells.

Amino Acid Sequence↗
PubMed1996

Hypertensive urgencies and emergencies. Prevalence and clinical presentation.

The prevalence and clinical picture of hypertensive urgencies and emergencies in an emergency department are poorly known. The aim of the present study was to evaluate the prevalence of hypertensive crises (urgencies and emergencies) in an emergency department during 12 months of observation and the frequency of end-organ damage with related clinical pictures during the first 24 hours after presentation. Hypertensive crises (76% urgencies, 24% emergencies) represented more than one fourth of all medical urgencies-emergencies. The most frequent signs of presentation were headache (22%), epistaxis (17%), faintness, and psychomotor agitation (10%) in hypertensive urgencies and chest pain (27%), dyspnea (22%), and neurological deficit (21%) in hypertensive emergencies. Types of end-organ damage associated with hypertensive emergencies included cerebral infarction (24%), acute pulmonary edema (23%), and hypertensive encephalopathy (16%) as well as cerebral hemorrhage, which accounted for only 4.5%. Age (67 +/- 16 versus 60 +/- 14 years [mean +/- SD], P < .001) and diastolic blood pressure (130 +/- 15 versus 126 +/- 10 mm Hg, P < .002) were higher in hypertensive emergencies than urgencies. Hypertension that was unknown at presentation was present in 8% of hypertensive emergencies and 28% of hypertensive urgencies. In conclusion hypertensive urgencies and emergencies are common events in the emergency department and differ in their clinical patterns of presentation. Cerebral infarction and acute pulmonary edema are the most frequent types of end-organ damage in hypertensive emergencies.

Age Factors↗
PubMed1995

An autocrine loop of HIV type-1 Tat protein responsible for the improved survival/proliferation capacity of permanently Tat-transfected cells and required for optimal HIV-1 LTR transactivating activity.

Human immunodeficiency virus type 1 (HIV-1) transactivating Tat protein is pivotal to virus replication. Tat's potential effects on HIV-1 pathogenesis, however, go well beyond its role in the virus's life cycle. Current data indicate that biologically active Tat is released from HIV-1-infected cells and readily endocytosed and targeted to the nucleus of nearby, or perhaps distant, cells, where it may exert a series of pleiotropic effects. This paracrine action has been extensively investigated, and depending on the amounts of exogenously added Tat, its effects may extend from the suppression of immunocompetent cells to transactivation of heterologous genes to the promotion of growth of Kaposi's sarcoma spindle cells. We have already observed that various cell lines, either permanently transfected with an expressive HIV-1 tat gene construct or cultured in the presence of exogenously added Tat protein, are protected from programmed cell death after serum withdrawal or other apoptotic stimuli. The present article shows that various types (lymphoblastoid, epithelial, neuronal) of permanently tat-transfected cell lines actively release fully bioactive Tat protein. The addition of anti-Tat antibody to the culture medium completely abolishes their increased survival/proliferation capacity in serum-free culture. In these conditions, therefore, the enhanced survival/proliferation potential of permanently tat-transfected cells seems entirely dependent on a Tat-protein autocrine loop. The finding that anti-Tat antibody, added to culture medium, exerts a negative influence on the expression of a Tat-responsive HIV-1 long terminal repeat chloramphenicol-acetyltransferase construct, transiently transfected into permanently tat-transfected cells, suggests that the Tat autocrine loop may also be required for optimal HIV-1 long terminal repeat transactivation.

Animals↗
PubMed1994

The use of lacidipine in the management of hypertensive crises: a comparative study with nifedipine.

This study estimated the efficacy of sublingual nifedipine 10 mg vs. sublingual lacidipine 4 mg in the management of hypertensive crises. We studied 40 patients with diastolic blood pressure > or = 120 mm Hg, who were divided into two groups of 20. Blood pressure and heart rate were assessed in the recumbent position before treatment and after 30, 120, and 240 min. Comparison of the effectiveness of these drugs was analyzed by Student's t test. Both drugs tested revealed a statistically significant hypotensive effect on diastolic and systolic blood pressure, and few side effects. Compared with lacidipine, nifedipine had a greater hypotensive effect on diastolic and systolic blood pressure in the first 30 min and on the diastolic blood pressure after the first 120 min. However, the hypotensive effect of lacidipine is statistically significant. After 4 h, both drugs showed a similar efficacy without significant statistical variations. We concluded that in the management of hypertensive crises the use of each of these drugs can have a particular range: nifedipine can be used when a pronounced and rapid blood pressure decrement is necessary, whereas lacidipine can be used when a more gradual effect is preferable.

Administration, Sublingual↗
PubMed1994

In vitro growth of human fetal CD34+ cells in the presence of various combinations of recombinant cytokines under serum-free culture conditions.

CD34+ cells were purified from midtrimester human fetal blood and adult bone marrow samples and seeded in serum-free fibrin-clot cultures in order to evaluate the number and the responsiveness to recombinant cytokines of pluripotent (CFU-GEMM), erythroid (BFU-E), megakaryocyte (BFU-meg and CFU-meg) and granulocyte/macrophage (CFU-GM) haemopoietic progenitor cells. The number of the different haemopoietic progenitors/1 x 10(3) CD34+ cells, except CFU-meg, was significantly higher in fetal blood than in adult bone marrow in cultures stimulated by any combination of cytokines including interleukin-3 (IL-3), granulocyte/macrophage colony stimulating factor (GM-CSF) or stem cell factor (SCF) plus erythropoietin (Epo). Nevertheless, whereas adult BFU-E showed a maximal growth in the presence of Epo plus IL-3 or Epo plus SCF, fetal BFU-E showed an optimal growth in the presence of Epo alone, the sensitivity of fetal BFU-E to suboptimal concentrations of Epo being approximately 10-15-fold higher than that of adult BFU-E. Addition of optimal concentrations of IL-3, GM-CSF or SCF, alone or in various combinations, to Epo-containing cultures induced a significant increase in both the number and size of fetal CFU-GEMM, and CFU-GM, and a parallel decrease of fetal BFU-E. Finally, SCF potently synergized with IL-3 in increasing the growth of both classes of fetal megakaryocyte progenitors, BFU-meg and CFU-meg.

Adult↗
PubMed1994

All-trans retinoic acid and induction of apoptosis in acute promyelocytic leukemia cells.

All-trans retinoic acid (ATRA) represents a highly effective treatment for acute promyelocytic leukemia (M3-ANLL). This compound induces the leukemic promyelocytes to differentiate into morphologically and phenotypically mature myeloid cells. The mechanism of action of ATRA is far from fully understood. It has recently been reported that, along with its differentiation activity, ATRA causes apoptosis in the acute promyelocytic leukemia cell line HL-60. In this study we attempted to test whether ATRA is also able to induce apoptosis in fresh leukemic cells from M3-ANLL patients. Our results indicated that although morphological differentiation was detectable in 9/9 M3-ANLL samples after in vitro exposure to ATRA 10(-6) M, the percentage of apoptotic cells in the treated samples did not significantly differ from that obtained in controls (13.1% vs 9.4% respectively, after 8 days exposure). These data suggest that apoptosis does not seem to be the key mechanism by which ATRA exerts its action in M3-ANLL, at least at the blast cell level.

Apoptosis↗
PubMed1993

Immunocytochemical analysis of phosphatidylinositol-specific phospholipase C in PC12 cells: predominance of the delta isoform during neural differentiation.

The rat pheochromocytoma PC12 cell line, which differentiates into sympathetic neurons under nerve growth factor (NGF) treatment, contains at least three phosphoinositidase C (PIC) isozymes, PIC beta, PIC gamma, PIC delta. These isozymes have been previously shown to display a different subcellular localization. To determine whether or not NGF induces changes in the presence and/or distribution of PIC isozymes during PC12 neural differentiation, studies were carried out by means of in situ immunocytochemistry. After NGF administration the proliferative activity was progressively reduced to very low levels, as measured by bromodeoxy Uridine incorporation, and a neuron-like morphology was displayed by almost all cells. In unstimulated PC12 cells, PIC beta was detected in the nucleus whereas PIC delta was only cytoplasmic; PIC gamma was found in both cell compartments. In cells treated with NGF for 3 days, neural processes extended to twice the diameter of the cell body; the gamma isoform was concentrated near the nucleus, while the immunoreactivity of the beta form remained constant and the delta form was increased. After 10 days of treatment with NGF, PIC beta was hardly detectable and PIC gamma immunostaining was considerably decreased. On the contrary, PIC delta progressively increased and, after 14 days of NGF exposure, fully differentiated cells displayed an intense labelling of cell body and neurites. In the same cells, PIC beta and PIC gamma were almost negative. These results suggest that NGF dependent neural differentiation is related to the selective down regulation of PIC beta and gamma and the increase of PIC delta isozyme associated with the decrease of cell proliferation.

Animals↗
PubMed1993

Influence of the human immunodeficiency virus type 1 Tat protein on the proliferation and differentiation of PC12 rat pheochromocytoma cells.

Rat pheochromocytoma PC12 cells were permanently transfected with a plasmid vector, containing the tat gene of human immunodeficiency virus type 1 (HIV-1). Various clones were obtained showing the production of different levels of bioactive Tat protein (Tat) after transient cotransfection with an HIV-1 long terminal repeat-chloramphenicol acetyltransferase reporter plasmid. Under conditions of serum starvation, tat-positive PC12 clones expressing high levels of Tat showed a significantly (P < 0.05) higher proliferation rate with respect to both mock-transfected PC12 cells and tat-positive PC12 cells expressing lower levels of Tat. Moreover, all tat-positive PC12 cell clones showed a partial morphological differentiation into sympathetic-like neurons, when seeded in low density (5 x 10(3) cells/cm2) cultures. On the other hand, mock-transfected PC12 cells showed the round shaped morphology typical of untreated PC12 cells and displayed signs of neuronal differentiation only after treatment with 100 ng/ml of nerve growth factor. The addition of 5 micrograms/ml of anti-Tat monoclonal antibody to the culture medium of tat-positive PC12 cell clones almost completely blocked their increased proliferation rate (P < 0.05), but did not affect neuronal differentiation. A significant (P < 0.05) increase in cell proliferation was consistently observed in PC12 cells supplemented with low concentrations of Tat (5 to 25 ng/ml), whereas neuronal differentiation was hardly affected by exogenous Tat. Our data strongly suggest that Tat exerts a complex influence on the proliferation and differentiation of PC12 cells, and this might help in increasing understanding of the pathogenesis of the frequent neurological disorders observed in AIDS patients.

Animals↗
PubMed1992

Discrete subcellular localization of phosphoinositidase C beta, gamma and delta in PC12 rat pheochromocytoma cells.

Phosphoinositidase C activity was revealed in nuclei isolated from PC12 rat pheochromocytoma cells incubated with tritiated phosphatidylinositol, phosphatidylinositol 4-phosphate and phosphatidylinositol 4,5-bisphosphate. Phosphoinositide breakdown was found to be optimal at neutral pH and Ca++ concentrations ranging from endogenous levels to millimolar values. To characterize the enzymes involved, three monoclonal antibodies directed against the beta, gamma and delta phosphoinositidase C isoforms were employed. A combination of Western blot immunochemical analysis on cytoplasmic and nuclear fractions and of in situ immunocytochemistry on intact cells and isolated nuclei indicated that phosphoinositidase C gamma, though predominantly cytoplasmic, was present in both cell compartments. On the contrary, phosphoinositidase C beta was exclusively localized in the nucleus, whereas phosphoinositidase C delta was restricted to the cytoplasm. These data suggest that inositol lipid breakdown is controlled by different phosphoinositidase C isozymes in the various cell compartments, and support the notion that a separate phosphoinositide signalling system is located in the nucleus.

Animals↗
PubMed1984

A fetal glycolipid expressed on adenocarcinomas of the colon.

Reactivity of neuraminidase-treated colorectal carcinoma cells with antibodies that detect the X-carbohydrate structure was greater than the reactivity of untreated cells. The same results were obtained with glycolipid extracts of meconium, a colorectal carcinoma cell line, three freshly excised human adenocarcinomas, and normal bronchial mucosa. The glycolipid was either not expressed or expressed in smaller quantities on the corresponding normal colon tissue. Further study showed that the major sialo-X glycolipid has six sugars including a single sialic acid which blocks X-antigenicity. These glycolipids were further analyzed by ion-exchange high-pressure liquid chromatography and thin-layer chromatography. These monosialo-X glycolipid antigens might serve as potential tumor markers.

Adenocarcinoma↗
PubMed1980

Radioimmunoassay of trypsin-like substance in human serum.

A radioimmunological method for circulating trypsin-like substances was set up, using cathodic trypsin (isolated from human pancreas) as immunogen, reference standard and material to label, and bovine serum to stabilize the system. The assay scheme included a bound-free separation by polyethylene-glycol precipitation after a 1-h incubation at room temperature. Some relevant points emerged from the validation experiments: a) the assay proved simple and reliable, meeting both requirements of a prompt clinical response and of a high sensitivity level (1.5 ng/ml or less); b) evidence was added to the view that cathodic trypsinogen is the immunoassayable species present in the blood stream; c) the parallelism of the radioimmunological responses of cathodic trypsin and trypsinogen demonstrated that a self-consistent analytical information may be derived using either references; d) the absence of detectable amounts of trypsin-like substances in sera from totally-pancreatectomized patients (3 cases) indirectly confirmed the organ-specificity of the measurement; e) a "normal" level of 27 +/- 8 ng trypsin equivalent/ml (X +/- SD, n = 82) resulted: some much higher literature data, all related to a single radioimmunoassay system (RIA-Gnost trypsin kit, Hoechst, FRG), are seemingly explained by the different purity observed for the reference materials.

Humans↗
PubMed1979

[Direct skin tests in the prevention of allergic reactions in surgical patients (500 cases)].

The methodology used to diagnose drug allergy in 500 surgical patients is described. After an introduction in which the choice of this method is justified, the used methods are shown in detail with the tested active pharmacological principles (it is a group of drugs for pre, intra and post-surgery use). The tested patients have been clinically watched during all their stay in hospital. The results achieved are shown, as well as the good mutual relation between anamnesis and clinical progress with the answers obtained from the tests. The detailed analysis of skin-reactions showed that positive answers against penicillin (in more than 37% of the tested cases) clearly prevailed over other drugs (petidinum about 12%; propanididum about 10%) etc. Skin-test positivity against prometazinum (6%) is stressed as being quite considerable, considering its prevalent anthistaminic pharmacological effect. The work ends showing how this method, if correctly used, can give good results which can be compared with the results achieved by other more sophisticated methodologies. The kind of test is recommended to be adopted by other hospitals to reduce the incidence of immunological pathogenesis diseases which is more and more frequent.

Drug Hypersensitivity↗
PubMed1979

Creatine kinase forms in human skeletal and cardiac muscle.

The creatine kinase (CK) activity in human skeletal and cardiac muscle submitted to QAE-Sephadex chromatography was found to distribute into three peaks (m and h I, II, III fractions). Characterization according to electrophoretic behaviour, approximate molecular weight, thermal stability and immunological properties unambiguously demonstrated the coincidence of fractions I and III with reference MM-CK and MB-CK isoenzymes, while both cardiac and muscular forms II proved to escape any assignment within the dimeric (M, B) model. A higher molecular weight than for reference CK and the absence of interaction with BB-antiserum resulted for both forms II, which on the contrary were found to diverge as for reactivity to MM-antiserum and stability characteristics. Quantitation of the CK forms, attempted on a limited number of samples, confirmed the expected relative levels of MM-CK and BB-CK and gave evidence for the presence of hII- or mII-CK amounting up to 30% of the total activity in cardiac and skeletal muscle, respectively. The results of the study both confirm a complexity greater than supposed for the CK system and point to the inadequacy of several of the commonly used analytical approaches to derive correct information.

Chromatography, Ion Exchange↗