Mitochondrial diseases and aging.
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Aging↗
Biomedical subjects
S Papa
Publications and source records attributed to S Papa.
Synthesis and biological activity of a series of isoindolone derivatives related to cytochalasins.
A series of hydrogenated isoindolone derivatives structurally related to cytochalasin B has been synthesized and their ability to induce binucleation in the human lymphocytes were tested. All compounds were found able to inhibit cell cytokinesis at different extent in the range (3.12-25 mumol/l) respect to the negative control; however the highest percentage of binucleated cells is induced by Cyt B.
Cell Nucleus↗
Quantitation of hemopoietic cell antigens in flow cytometry.
Using appropriate standards immune flow cytometry permits quantitative analysis of the expression levels of cellular antigens. This information can be gained on an absolute basis and reported in terms of numbers of molecules per cell. This offers clues for reaching time-to-time and lab-to-lab comparability of immuno-fluorescence data. After briefly reminding the characteristics of available standards this paper provides an overview of the main relevant candidate molecules for flow cytometric quantitation on hemopoietic cells and reviews the major fields of application in immuno-hematology.
Animals↗
Immunophenotype definition of the stem/progenitor cell compartment. Implications for the identification of blast cells in acute leukemia.
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Acute Disease↗
Moving towards the definition of new clusters of designation at the 6th International Workshop on Human Leukocyte Differentiation Antigens. A brief description of the recently clustered molecules.
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Antigens, CD↗
Oxidative phosphorylation and F(O)F(1) ATP synthase activity of human hepatocellular carcinoma.
A study of mitochondrial oxidative phosphorylation in biopsies from human hepatocellular carcinoma is presented. Tumour mitochondria as compared to control liver mitochondria, besides a reduced activity of complex IV (cytochrome c oxidase) of the respiratory chain, show a decreased phosphorylative capacity. This appears to be mainly related to a defective F o F(1) ATP synthase complex. Use of an antibody against the F(1) portion of the complex demonstrate a definite decrease for the beta subunit of F(1) in tumour mitochondria.
Adenosine Triphosphatases↗
Characterization of proteins phosphorylated by the cAMP-dependent protein kinase of bovine heart mitochondria.
Characterization of two mitochondrial proteins of M(r) 42 and 18 kDa, respectively, phosphorylated by the cAMP-dependent protein kinase of bovine heart mitochondria (mtPKA), is presented. A 42 kDa protein is found to be loosely associated to complexes I, III and IV of the respiratory chain and complex V (ATP synthase) in the inner mitochondrial membrane. An 18 kDa protein is associated to complex I in the inner membrane and in a purified preparation of this complex where it can be phosphorylated by the isolated catalytic subunit of PKA.
Adenosine Triphosphatases↗
Functional analysis of subunits III and IV of Bacillus subtilis aa3-600 quinol oxidase by in vitro mutagenesis and gene replacement.
Using the high efficiency of homologous gene recombination in Bacillus subtilis, a strategy for mutational analysis of the proton pumping aa3-600 quinol oxidase of this organism has been developed. The qox operon with the qoxA, qoxB, qoxC and qoxD genes, coding for the four subunits of this oxidase, was deleted and then replaced with mutated copies in which qoxC (subunit III) or qoxD (subunit IV) genes were deleted. The complete deletion of the qox operon caused disappearance of heme aa3-600 and a slight depression of the overall respiratory activity, compensated by alternative oxidase with no proton pumping activity. Deletion of qoxC probably resulted in a defective assembly of the aa3-600 quinol oxidase. The strain with deletion of qoxD gene expressed normal content of heme aa3-600 but exhibited a reduced respiratory activity and a significantly depressed proton pumping activity. These results show that subunit IV is critical for the activity of the proton pumping aa3-600 quinol oxidase.
Bacillus subtilis↗
Correlation between rat liver regeneration and mitochondrial energy metabolism.
The time course of changes in mitochondrial energy metabolism during liver regeneration, following partial hepatectomy, is analyzed. For 24 h after surgical operation, a lag phase in the time course of the growth of liver is observed. In this period mitochondria showed a decrease of: (1) the respiratory control index; (2) the rate of oxidative phosphorylation; (3) the amount of immunodetected beta-F1 and F01-PVP subunits of F0F1-ATP synthase. No decrease, but instead a small increase in the content of mRNA for beta-F1 was observed in this phase. After this lag phase the growth of liver started, the content of mRNA for beta F1, as well as the level of immunodetected mitochondrial beta-F1 and F01-PVP subunits, increased and oxidative phosphorylation recovered. Analysis of the relative beta F1 protein/mRNA ratio indicates a decrease of beta F1 translational efficiency which remained low up to 72 h after partial hepatectomy and reached the same ratio of control at 96 h. It is concluded that the regenerating capability of rat liver is correlated with the efficiency of oxidative phosphorylation.
Animals↗
Transfection of mitochondria: strategy towards a gene therapy of mitochondrial DNA diseases.
Successes in classical gene therapies have been achieved by placing a corrected copy of a defective nuclear gene in cells. A similar gene replacement approach for a mutant mitochondrial genome is invariably linked to the use of a yet unavailable mitochondrial transfection vector. Here we show that DNA coupled covalently to a short mitochondrial leader peptide (chimera) can enter mitochondria via the protein import pathway, opening a new way for gene-, antisense-RNA- or antisense-DNA-delivery in molecular therapies. The import behavior of the purified chimera, composed of the amino-terminal leader peptide of the rat ornithine transcarbamylase (OTC) and a double stranded DNA molecule (17 bp or 322 bp), was tested by incubating with coupled and 'energized' rat liver mitochondria in the presence of reticulocyte lysate. The chimera was translocated with a high efficiency into the matrix of mitochondria utilizing the protein import pathway, independent from the size of its passenger DNA.
Amino Acid Sequence↗
Proton/electron stoichiometry of mitochondrial bc1 complex. Influence of pH and transmembrane delta pH.
The effect of pH and transmembrane delta pH on the efficiency of the proton pump of the mitochondrial bc1 complex both in situ and in the reconstituted state was studied. In both cases the H+/e- ratio for vectorial proton translocation by the bc1 complex respiring at the steady state, under conditions in which the transmembrane pH difference (delta pH) represents the only component of the proton motive force (delta p), was significantly lower than that measured under level flow conditions. The latter amounts, at neutral pH, to 1 (2 including the scalar H+ release). In the reconstituted system steady-state delta pH was modulated by changing the intravesicular buffer as well as the intra/extra-liposomal pH. Under these conditions the H+/e- ratio varied inversely with the delta pH. The data presented show that delta pH exerts a critical control on the proton pump of the bc1 complex. Increasing the external pH above neutrality caused a decrease of the level flow H+/e- ratio. This effect is explained in terms of proton/electron linkage in b cytochromes.
Animals↗
[The role of the radiological hemithorax examination in closed trauma of the chest].
January, 1992, to September, 1994, a hundred and seventy-eight blunt chest trauma patients were examined with plain chest films and detailed rib studies. The patients were subdivided into three groups according to: a) the presence/absence of rib fractures correlated with clinical data; b) the depiction of rib fractures and/or thoracic complications; c) treatment customization in the presence/absence of rib fractures. In our series of patients the clinical data and the presence of rib fractures were poorly correlated. The detection rates of minor and major complications were also investigated on plain chest films and detailed rib studies. Plain chest films most frequently depicted the complications requiring conservative or surgical management and gave the indication for further imaging investigations. The detailed rib studies of the involved hemithorax yielded no further information useful to therapy except in few cases: and should therefore be limited to the cases exhibiting complications on chest films, which may benefit from surgical fixation. The accurate study of rib fractures is paramount in the cases where legal action may be undertaken.
Humans↗
All-trans-retinoic acid induces simultaneously granulocytic differentiation and expression of inflammatory cytokines in HL-60 cells.
All trans-retinoic acid (ATRA) can induce granulocytic differentiation both in vitro and in vivo, and its activity is mediated by the retinoic acid receptor-alpha (RAR-alpha). In the present study, we evaluated the ability of this inducer in HL-60 cells, to stimulate simultaneously granulocytic differentiation and the expression of the cytokines interleukin-1 alpha (IL-1 alpha), IL-1 beta, IL-3, IL-6, tumor necrosis factor-alpha (TNF-alpha), and stem cell factor (SCF). The level of expression of these cytokines in ATRA-treated HL-60 cells was compared with that observed in normal and lipopolysaccharide (LPS)-treated peripheral granulocytes. The results indicate that the expression of these cytokines is enhanced during differentiation so that the pattern observed in ATRA-treated HL-60 cells is close to that of LPS-stimulated normal granulocytes. In addition, tetra phorbol acetate (TPA)-treated HL-60 cells express several of the above listed cytokines. It is concluded that ATRA not only induces granulocytic differentiation of HL-60 cells, but also activation of these terminally differentiated cells. The activating cytokine expression in these cells appears related to the progress of the differentiation program induced by ATRA since normal granulocytes do not respond to this inducer by activation of the expression of these genes. Furthermore, the cytokine activation is a specific effect of ATRA, since DMSO does not have any stimulatory effect.
Base Sequence↗
[Incidence of dilatation of residual cystic duct in liver transplantation. Our experience with 152 cases].
In our series of patients, we studied the incidence of residual cystic duct mucocele, which is still considered a rare complication in orthotopic liver transplantation (OLT). 152 OLTs were performed in 138 patients in the II Surgery Dept. of Bologna University, May 1986 to June 1994; a termino-terminal choledocho-choledochal anastomosis was performed in 145 of them. A choledocho-jejunal anastomosis was performed in other 7 patients. In 3 patients we observed an anechoic ovoidal structure localized just before the portal vein, near the main bile duct (MBD). Then, we monitored the evolution of this finding by ultrasonography (US), Doppler US, CT and CT-cholangiography. Integrated imaging, clinical and surgical data, led to the diagnosis of non-obstructive mucocele of residual cystic duct in OLT. To date, this complication has not led, on our series, to the necessity of new surgical procedures for cholestasis by MBD compression, which is in disagreement with literature data. In our series, the incidence of residual cystic duct mucocele is 2%, which is a higher value than those reported in the literature, suggesting that this condition be investigated carefully as a non-rare complication in OLT.
Adult↗
Role of nuclear-encoded subunits of mitochondrial cytochrome c oxidase in proton pumping revealed by limited enzymatic proteolysis.
The role of supernumerary subunits of bovine heart cytochrome c oxidase has been investigated by examining the effect on the enzymatic activity of limited proteolysis by chymotrypsin, thermolysin, and trypsin. All three proteases, when added to the soluble oxidase, digested subunits III, VIa, and VIb and caused inhibition of electron flow in the oxidase. In addition, trypsin and thermolysin also digested subunit IV. Trypsin cleaved off an N-terminal segment of seven residues; thermolysin cleaved only the first four residues at the N-terminus of subunit IV. Digestion of the soluble oxidase by trypsin but not by thermolysin caused decoupling of redox-linked proton pumping in the oxidase. It is concluded that the sequence V5-V6-K7 of the hydrophilic N-terminus of subunit IV, which protrudes out of the matrix side of the mitochondrial membrane, mediates the access of protons into the transmembrane proton translocating pathway in the oxidase.
Amino Acid Sequence↗
cAMP-dependent protein phosphorylation in mitochondria of bovine heart.
A study is presented of the cAMP-dependent phosphorylation in bovine heart mitochondria of three proteins of 42, 16 and 6.5 kDa associated to the inner membrane. These proteins are also phosphorylated by the cytosolic cAMP-dependent protein kinase and by the purified catalytic subunit of this enzyme. In the cytosol, proteins of 16 and 6.5 kDa are phosphorylated by the cAMP-dependent kinase. It is possible that cytosolic and mitochondrial cAMP-dependent kinases phosphorylate the same proteins in the two compartments.
Animals↗
Cross-reconstitution studies with polypeptides of Escherichia coli and bovine heart mitochondrial F0F1 ATP synthase.
To characterize the role of supernumerary subunits of the mammalian F0F1 ATP synthase, cross-reconstitution of mitochondrial and bacterial F0F1 complexes has been carried out. Escherichia coli F1 (EcF1) can be reconstituted with F1-stripped everted membranes of E. coli (UPEc) and of bovine heart mitochondria (USMP). Bovine heart mitochondrial F1 (BHF1) can also be reconstituted with both membranes. Both EcF1 and BHF1, when reconstituted with UPEc, exhibited oligomycin-insensitive ATP-hydrolase activity. Subunits of the mammalian F0, in particular F0I-PVP protein, F6 and oligomycin-sensitivity-conferring protein (OSCP) conferred oligomycin sensitivity to the catalytic activity of EcF1 or BHF1 reconstituted with UPEc. Reaction of N,N'-dicyclohexylcarbodiimide and development of inhibition of passive H+ conduction was, in UPEc, considerably slower and exhibited a lower apparent affinity than in USMP. The ATP hydrolase activity of UPEc+EcF1 or UPEc+BHF1 was, also, less sensitive to inhibition by N,N'-dicyclohexylcarbodiimide than USMP+EcF1 or USMP+BHF1. Addition of mitochondrial F0I-PVP to UPEc enhanced the sensitivity of H+ conduction to oligomycin. F0I-PVP and OSCP added to UPEc, promoted inhibition by N,N'-dicyclohexylcarbodiimide of passive H+ conduction and increased its binding affinity to subunit c of E. coli F0. The presence of F0I-PVP and OSCP also promoted inhibition by N,N'-dicyclohexylcarbodiimide of the ATP-hydrolase activity of EcF1 or BHF1 reconstituted with UPEc.
Adenosine Triphosphate↗
Decline with age of the respiratory chain activity in human skeletal muscle.
Mitochondrial respiratory systems have been screened in 63 orthopaedic patients of age ranging between 17 and 91 years. The results show a statistically significant definite decrease with ageing of mitochondrial respiratory activity with pyruvate plus malate, succinate and ascorbate plus TMPD. This pattern is associated with an equally significant decrease with age of the enzymatic activity of complex I, II and IV. No significant decrease with age is, on the contrary, observed in the mitochondrial content of cytochromes a+a3, and c+c1. Preliminary Western blot analysis indicates an altered polypeptide pattern in cytochrome c oxidase. This study provides evidence for a decline with age of mitochondrial respiratory activity in human skeletal muscle, affecting complex I, II and IV.
Adolescent↗