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D Barbieri

Publications and source records attributed to D Barbieri.

At least 55 records · Page 3Linked to original sources
PubMed1994

Mitochondrial modifications during rat thymocyte apoptosis: a study at the single cell level.

Apoptosis is an active type of cell death, occurring under several physiological and pathological conditions. The role of cellular organelles such as mitochondria in this process is still an open question. We recently described a new method to measure mitochondrial membrane potential in intact cells using flow cytometry. Using this method we studied alterations of mitochondrial membrane potential in a classical model of apoptosis, i.e., dexamethasone-treated rat thymocytes. Moreover, apoptosis induced by heat shock was also studied in the same cells. Mitochondria are functionally intact during the early phases of apoptosis, when DNA fragmentation occurs, whereas early alteration in their potential and mass takes place after DNA damage. According to flow-cytometric analysis, the presence of a hypodiploid peak, an index of nuclear DNA loss, predates depolarization of mitochondrial membrane and decrease of mitochondrial mass. Loss of plasma membrane integrity, which indicates cell death and is revealed by the permeability to propidium iodide, eventually follows. All these phenomena are more evident in dexamethasone-treated cells than in heat-shocked cells. Thus, in these types of apoptosis the involvement of mitochondria is apparently not a primary event.

Animals↗
PubMed1994

Antiapoptotic effect of c-fes protooncogene during granulocytic differentiation.

The c-fes protooncogene is expressed at high levels in the terminal stages of granulocytic differentiation. Its product, p92c-fes, exhibits a tyrosine-kinase activity and is involved in the cellular response to GM-CSF, but its role is not yet clarified. To study this problem, the c-fes protooncogene expression has been inhibited in HL60 cells and in fresh leukemic blast cells of Acute Promyelocytic Leukemia (APL) induced to differentiate with All-Trans-Retinoic Acid (ATRA). Inhibition of c-fes function was obtained by treatment of the cells with a specific antisense oligomer complementary to the 5' region of the c-fes mRNA. It was observed that the cells, rather then differentiate to granulocytes, underwent premature cell death showing the morphological and molecular characteristics of apoptosis. Superimposable results are obtained on blast cells from APL. It is possible to conclude that the loss of cell viability that occurs during the in vitro differentiation of myeloid cells, after the complete inhibition of c-fes expression and treatment with ATRA, is due to activation of programmed cell death rather than an accelerated differentiation. Our data suggest that the c-fes product is essential for the survival of myeloid cells during differentiation.

Apoptosis↗
PubMed1993

Transcription factors DNA-binding activity in rat thymocytes undergoing apoptosis after heat-shock or dexamethasone treatment.

The onset of apoptosis is generally thought to require the induction of a novel genetic program. Accordingly, we studied the kinetic of DNA-binding activity of several transcription factors in rat thymocytes undergoing apoptosis induced by dexamethasone (DEX) or heat shock (HS) treatment. Here we report that: 1) early activation of AP-1 occurred in both models of apoptosis, even if the intensity of activation and AP-1 complex composition were different and much less evident in HS-treated thymocytes; 2) early NFkB DNA-binding activity was also observed in both types of apoptosis; 3) downregulation of other transcription factors, such as OCT-1 and CREB, with high constitutive activity, was recorded in both models of apoptosis. The fact that some TFs are up-regulated while others are down-regulated suggests that apoptosis is the result of a complex combination of positive and negative signals regulating gene expression.

Animals↗
PubMed1993

Inhibition of c-fes expression by an antisense oligomer causes apoptosis of HL60 cells induced to granulocytic differentiation.

The c-fes protooncogene is expressed at high levels in the terminal stages of granulocytic differentiation, but so far no definite function has been attributed to the product of this oncogene. To tackle this problem, the c-fes protooncogene expression has been inhibited in HL60 cells, and fresh leukemic promyelocytes of acute promyelocytic leukemia have been induced to differentiate with retinoic acid (RA) and dimethylsulfoxide (DMSO). Inhibition was obtained by incubating the cells with a specific c-fes antisense oligodeoxynucleotide. It was observed that the cells, rather than differentiating, underwent premature cell death showing the morphological and molecular characteristics of apoptosis. This process was inhibited by granulocyte and granulocyte/macrophage colony-stimulating factor, but not by interleukin 3 (IL-3), IL-6, or stem cell factor. Our present results demonstrate that the loss of cell viability that occurs during the in vitro differentiation of myeloid cells, after the complete inhibition of the c-fes gene product and treatment with RA-DMSO, is due to activation of programmed cell death. It is concluded that a possible role of the c-fes gene product is to exert an antiapoptotic effect during granulocytic differentiation.

Apoptosis↗
PubMed1992

Studies of the relationship between cell proliferation and cell death. II. Early gene expression during concanavalin A-induced proliferation or dexamethasone-induced apoptosis of rat thymocytes.

Several data in the literature suggest that an intriguing relationship exists between cell proliferation and cell death. Accordingly, we studied the early expression of different genes in the same cells, i.e. rat thymocytes, undergoing cell proliferation upon stimulation with Concanavalin A or cell death following dexamethasone treatment. We showed that an early accumulation of c-fos, c-jun and c-myc mRNA occurred in both phenomena but with different kinetics. It can be speculated that the early induction of nuclear oncogenes is necessary to allow the later induction of other genes probably regulated at the transcriptional level by the AP-1 complex and/or by Myc protein. The accumulation of the transcript for another gene, i.e. poly(ADP-ribose)polymerase, an enzyme responsible for posttranslational modifications of several nuclear proteins, could instead be related to chromatin modifications occurring in both processes.

Animals↗
PubMed1992

Inhibition of apoptosis by zinc: a reappraisal.

Apoptosis--or programmed cell death--is an active type of cell death, occurring in several pathophysiological conditions. One of the most important characteristics of apoptosis is that cell death is preceded by DNA fragmentation, consequent to the activation of nuclear calcium- and magnesium-dependent endonuclease(s). DNA fragmentation can be inhibited by zinc ions. By using several techniques, such as DNA agarose gel electrophoresis, cytofluorimetric analysis of DNA content and of cell cycle, 3H-thymidine incorporation and trypan blue dye exclusion test, we show that zinc, despite completely inhibiting DNA fragmentation and the consequent loss of nuclear DNA content, does not protect rat thymocytes from spontaneous or dexamethasone-induced death. Our data also suggest that DNA fragmentation, although characteristic, is not a critical event for thymocyte death of apoptotic type.

Animals↗
PubMed1992

Italian multicenter study on a single lead VDD pacing system using a narrow atrial dipole spacing.

Since November 1988, 514 patients with advanced atrioventricular (AV) block and normal sinoatrial function have received the single lead VDD pacing system Twinal 30 Lem/CCS in 30 Italian centers. At implantation, particular attention was paid to the correct positioning of the atrial dipole in the mid- to mid-high right atrium and to the atrial electrogram characteristics. The follow-up included a chest X ray, to be performed before discharge of the patient from the hospital, telemetric evaluations of the endoatrial potential, provocative tests for interferences by myopotentials, 24-hour ambulatory EGG recordings, and where possible, exercise stress tests. The mean follow-up duration was 15.2 months, ranging from 1 to 42 months. A very low percentage of chronic atrial fibrillation, loss of atrial sensing, and system replacement was reported, most of the patients (93.5%) being paced in VDD mode. All investigations indicated an excellent overall system performance, stable AV synchrony, and infrequent myopotential interference, and a low complication rate throughout the follow-up period.

Aged↗
PubMed1991

[Transient hyperglycemia in acute myocardial infarct: the short- and long-term risk factor for mortality].

To evaluate the prevalence and prognostic significance of hyperglycemia in acute myocardial infarction, we studied 700 patients (mean age 63.3 +/- 10.97) subsequently admitted to the UCIC of Tradate Hospital during the period January 1976 to December 1987. Patients were followed up for a median period of four years. On the basis of fasting blood glycaemia values in the first five days of hospitalization, excluding the admission day, patients were divided into groups: 401 patients (57.0%) with constantly normal glycaemia; 84 patients (12.0%) with glycaemia equal or superior to 120 mg/100 ml, and with subsequent normalization; and 215 patients (31.0%) with diabetes mellitus diagnosed before hospitalization and/or with persistent hyperglycaemia. The overall mortality was 284 (40.5%) and cardiovascular deaths were 90.8%. Within the first month of myocardial infarction 98 patients died. The mortality rate was 9.4% in normoglycaemic patients and 20.2% in transient hyperglycaemic patients, similar to the value observed in diabetic patients (20.0%). During the follow-up 186 patients died. Late mortality after the first month is higher in diabetic patients (40%) and patients with transient hyperglycaemia (37%) compared to normoglycaemic patients (25.3%). Multivariate analysis shows that independent predictive variables are: for mortality in the first month, Killip class only; and after the first month, Killip class, metabolic classification, sex and supraventricular arrhythmias. The present study shows that transient hyperglycaemia has a low prevalence in the first days of acute myocardial infarction. Transient hyperglycaemia could be attributed not only to increased sympathetic tone elicited by acute myocardial infarction, but is probably a pathologic condition with an adverse outcome to which multiple factors contribute.

Age Factors↗
PubMed1990

AV delay and exercise stress tests: behavior in normal subjects.

In normal subjects the atrioventricular (AV) conduction is accelerated during exertion. The relationship between heart rate and AV delay is usually described as "linear". Looking at the increasing importance given to an appropriate AV synchrony in permanent dual chamber and P synchronous pacing we present the results of an investigation performed to study the correlation between AV conduction time and heart rate under stress conditions, and disclose some new aspects of this matter, which will possibly be useful for a further improvement of pacemaker technology.

Adult↗
PubMed1990

A new single lead VDD pacing system.

In 24 patients with advanced heart block and normal sinus node function, a new single lead VDD pacing system was implanted. At implantation, the endoatrial, bipolar electrogram was recorded in all patients. The lead position was checked by means of chest X-ray. At discharge and after 1, 3, and 6 months, testing for myopotential inhibition, telemetric evaluation of the endoatrial potential, and Holter recordings were made. After discharge, 18 patients performed two cardiopulmonary exercise tests at two different rate-matched AV intervals. All investigations showed good AV synchrony and a lack of interferences by myopotentials. The maximum rate-matched AV interval provided a significantly improved exercise capacity, which was more evident in patients with signs of myocardial failure.

Aged↗
PubMed1989

A procedure to obtain long-lasting fluorescence in formaldehyde fixed tissues.

The authors made a study of the small intestine by immunofluorescence in 5% phosphate-buffered formaldehyde fixed tissues, using the Nairn (1976) technique associated with Evans blue (Fry and Wilkinson 1963). The ability of the sections to fluoresce has been maintained after a storage time of more than 4 years. Similar very good results were obtained when skin biopsies from pemphigus foliaceus patients were fixed in formaldehyde for two h and afterwards washed in 30% sucrose solution for 12 to 18 h.

Biopsy↗
PubMed1989

Morphometric quantification of plasma cells in the intestinal mucosa of children. A comparative study between two sampling procedures.

In an attempt to obtain a sampling procedure of known accuracy for plasma cell quantification, applicable for routine analysis, we counted IgA, IgM and IgG producing cells in the lamina propria of the small intestine of six children by the method II of Aherne (1976), using two sampling procedures. In the first, we determined the number of cells in each one of 200 successive microscopic fields without specifying their localization in the mucosa. Proper tests upon this data showed that in order to estimate the number of IgA producing cells per mm3 of lamina propria with a confidence of 95% that the mean of the sample would not differ by more than 5% from the mean of the population, it would be necessary to count 850-900 microscopic fields. With a confidence of 90% that the two means cited will not differ between them by more than 10%, the number of fields to be counted would lie in the range of 150 to 200. In the second procedure we arbitrarily divided the mucosa into upper, middle and lower segments, identifying and counting the number of cells in each segment. Consistent results for the number of IgA, IgM and IgG-containing cells were obtained by averaging the data of sufficient number of counts of 30 fields: 10 in the upper segment, 10 in the middle segment and 10 in the lower segment. Means obtained by stratified counts of IgA producing cells in 60 microscopic fields, 20 in each segment, differed, in 93% of the samples, by no more than 10% from the mean derived from the counts of 200 successive fields. Stratified sampling also enabled us to detect a segmental variation which had not thus far been quantified. In all cases, it was observed that the numerical concentration of IgA producing cells was greater in the lower region than in the middle zone, while for both IgM and IgG cells the larger numbers occurred in the middle and lower segments. The lowest concentration of IgA, IgM and IgG cells occurred at the top of the villi.

Child↗
PubMed1989

[The effect of age and sex on gallbladder motor dynamics. An echographic study].

Aging and female sex are major risk factors for cholesterol gallstones: in addition to hepatic secretion of lithogenic bile, decreased gallbladder contractility may play a role in such physiological conditions. This study was aimed at evaluating the effect of age and sex on gallbladder kinetics in healthy subjects. Gallbladder volume was measured on the US images of 157 fasting subjects using the sum-of-cylinders method. No significant difference was observed between males and females. On the contrary, age was shown to have a significant positive correlation with fasting gallbladder volume, particularly in males. In a second group of 63 healthy volunteers gallbladder volumes were evaluated both before and after a standard meal. The subjects were grouped according to age, and fasting gallbladder volume appeared to be significantly greater in the groups formed by older people. Gallbladder volumes were compared in younger groups (under 35), and gallbladder emptying resulted to be much more complete in males than in females. On the contrary, no significant difference was observed between males and females over 50--which suggests a possible role of sex- and age-related hormonal factors. The above changes in gallbladder function may facilitate bile stasis which might in turn contribute to the increased risk for cholesterol gallstones notoriously associated with advanced age and female sex.

Adolescent↗
PubMed1988

Failure of the stem in total hip replacement. A study of aetiology and mechanism of failure in 13 cases.

Thirteen failed stem of Total Hip Replacement were studied: 9 were Charnley THR from an homogeneous series, which gives an incidence of 2.4% of stem fractures with a follow-up of 9-16 years; 4 were Mueller THR. Fatigue fracture of the stem occurred by defective support of the proximal part of the femur, following resorption of the calcar. In all cases reactive tissue to foreign body particles, metal and polyethylene, was found where bone resorption occurred. In Mueller THR wear of the cup produced the large amount of polyethylene particles; in Charnley THR metal particles prevailed and corrosion of the stem is suggested to be the initiating factor.

Aged↗