False aneurysm after transplant nephrectomy. Report of two cases.
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Adolescent↗
Biomedical subjects
J Ferreira
Publications and source records attributed to J Ferreira.
The biogenesis of the coiled body during early mouse development.
The coiled body is an ubiquitous nuclear organelle that contains essential components of the pre-mRNA splicing machinery as well as the nucleolar protein fibrillarin. Here we have studied the biogenesis of the coiled body in early mouse embryos. The results show that coiled bodies form and concentrate splicing snRNPs as early as in the maternal and paternal pronuclei of 1-cell embryos. This argues that the coiled body is likely to play a basic role in the nucleus of mammalian cells. In order to correlate the appearance of coiled bodies with the onset of transcriptional activity, embryos were incubated with brominated UTP and the incorporated nucleotide was visualized by fluorescence microscopy. In agreement with previous studies, transcriptional activity was first observed during the 2-cell stage. Thus, coiled bodies form before activation of embryonic gene expression. The appearance of coiled bodies in 1-cell embryos was preceded by the formation of morphologically distinct structures that also contain coilin and which we therefore refer to as pre-coiled bodies. At the electron microscopic level pre-coiled bodies have a compact fibrillar structure, whereas coiled bodies resemble a tangle of coiled threads. Although both pre-coiled bodies and coiled bodies contain the nucleolar protein fibrillarin, the assembly of coiled bodies is separated both in time and in space from ribosome synthesis. Our results suggest that the embryonic 'nucleolus-like body' is a structural scaffold that nucleates independently the formation of the coiled body and the assembly of the machinery responsible for ribosome biosynthesis.
Animals↗
[The evolution of the arterial pressure during a stress test in patients with hypertrophic myocardiopathy].
OBJECTIVES: To study the exercise blood pressure response in patients with hypertrophic cardiomyopathy (HC) and its relationship with sudden death. DESIGN: Retrospective study. POPULATION: We studied 51 patients (P) with HC: 18 women and 33 men. Their average age was 45 +/- 14 years, with a mean follow-up of 55 +/- 37 months. METHODS: Every patient had been subjected to a treadmill stress-test, a 24-hour Holter monitoring and an echocardiographic examination. Particular emphasis was given to blood pressure increments (BPI) during stress-test, the existence of premature ventricular contractions with a frequency of 10 or more per hour (PVC > or = 10), the occurrence of couplets (C) and/or non-sustained ventricular tachycardia (NSVT) on a 24-hour Holter. Finally, the finding of systolic anterior motion (SAM) of the mitral valve, in the routine echocardiogram, was valued. RESULTS: Four patterns of BPI were identified: "1": normal evolution (27 P); "2": plateau type increment (16 P); "3": fall in blood pressure during exercise (6 P); "4": abnormal BPI during recovery (2 P). Two groups were considered: group N-normal BPI, group A-patients with abnormal blood pressure responses. There were no significant differences among therapeutic agents, between the two groups, when the stress-test was performed. SAM was found in 21 P. Only 8 P registered ventricular arrhythmias, half of them with NSVT. No statistical relations were found between BPI and P age, the presence of SAM, PVC > or = 10, C, or NSVT. We found 78% of P in group N in NYHA class I. In contrast, in group A only 46% were in class I (p = 0.04). Only one death, of non cardiac cause, occurred (group A). CONCLUSIONS: There is a large number of patients with HC and abnormal BPI. This is, seemingly, not influenced either by a dynamic left ventricular gradient or by ventricular ectopic beat occurrence. However, a relation appears to exist between the abnormal response and functional class, not explained by the usual (noninvasive) clinical tests.
Adult↗
[Response of the left ventricular ejection fraction,assessed by by radionuclide angiography, to inotropic stimulation: its relationship with the reversibility of perfusion defects in thallium-201 scintigraphy with overload-reinjection protocol].
BACKGROUND: Reversibility of perfusion defects and left ventricular (LV) ejection fraction (LVEF) response to low-dose catecholamines may reflect complementary aspects of myocardial viability, in patients with CAD and LV dysfunction in whom revascularization is considered. OBJECTIVE: To evaluate the relationship between LVEF response to inotropic stimulation with adrenaline (delta LVEF) and myocardial perfusion. DESIGN AND SETTING: Prospective study in a cardiology department with referral for revascularization and transplantation. PATIENTS: 45 patients (pt) with compromised LVEF (< 45%) after myocardial infarction (MI). METHODS: Radionuclide ventriculography at baseline and during graded adrenaline infusion until 12 micrograms/min: an empirical cut-off value of delta LVEF of 8% was used to define groups with (CR+) or without (CR-) contractile reserve. Stress-reinjection 201TI SPECT: perfusion was classified with a weighted score based on visual analysis of extent and intensity of thallium uptake in five major myocardial segments, with results expressed as percent of myocardium classified as normal (%N), with fixed defects (%F), and with reversibility (%R). MAIN RESULTS: Groups CR+ (23 pt) and CR- (22 pt) had similar baseline LVEF (29.6 +/- 7.4 and 26.4 +/- 8.1), while delta LVEF was respectively 13.6 +/- 4.6 and 2.9 +/- 3.3. When compared to the other group, CR+ patients had, in average, 1.0 segment more with definite reversibility and 1.6 segments less with fixed defects; in terms of percentage of myocardium, CR+ patients had more extensive reversible areas (%R: 15.3 +/- 11.7 vs 4.7 +/- 5.0, p < 0.001), smaller irreversible areas (%F: 30.7 +/- 14.5 vs 45.6 +/- 16.1, p = 0.02) and similar extent of normal areas (54.0 +/- 14.6 vs 49.7 +/- 16.4). Patients with more extensive fixed defects had worse delta LVEF in response to adrenaline (p < 0.002, r = -0.45). Greater %R was positively correlated with delta LVEF (p < 0.02, r = 0.35). In all patients, delta LVEF with adrenaline was superior or equal to (%R/2)-10. No patient with %R > or = 15 had delta LVEF < 8%. However, ten patients had delta LVEF > or = 8% despite lesser degrees of %R. CONCLUSION: Our data suggest a clear association between myocardial inotropic reserve and the extent of potentially viable myocardium (as evaluated by stress-reinjection thallium SPECT), in patients with left ventricular dysfunction after myocardial infarction. Further assessment is needed to clarify the relative role of radionuclide ventriculography with inotropic stimulation in viability evaluation, notably with inclusion of regional wall motion information and with reassessment of patients after revascularization, when performed.
Adult↗
[Effectiveness and safety of coronary vasodilation with adenosine triphosphate with thallium-201 for the diagnosis of coronary disease].
OBJECTIVE: To evaluate the accuracy and safety of pharmacologic stress testing with adenosine triphosphate (ATP) associated with thallium-201 scintigraphy for detection of coronary artery disease. PATIENTS: We studied 44 patients, 35 male and 9 female with a mean age of 59 + 9 years. Previous myocardial infarction was present in 15 patients. Thirty-two patients underwent coronariography that revealed coronary artery disease in 28 patients. METHODS: ATP (Stryadine) was infused at a rate of 140 micrograms/kg/min for 6 minutes and 2 mCi of thallium-201 was injected at the third minute. Stress and redistribution SPECT acquisitions were performed respectively 5-10 minutes and 4-6 hours after ATP infusion. RESULTS: The incidence of side effects was 77% and chest pain was the most frequent (45%). Dyspnea occurred in 2 patients and only one patient presented transient first degree AV block. No serious or severe side effect occurred. In patients without myocardial infarction 14 of 16 patients with significant coronary artery disease had reversible perfusion defects demonstrated by ATP thallium-201 scintigraphy (sensitivity 88%) and all of 4 patients without significant coronary artery disease had normal myocardial perfusion (specificity 100%). The overall accuracy for detecting the presence of coronary artery disease was 90%. The test demonstrated an overall accuracy of 88% for detecting left anterior descending artery disease, 91% for circumflex artery disease and 80% for right coronary artery disease. CONCLUSIONS: Pharmacologic stress with ATP associated with thallium-201 scintigraphy, is a safe and high accurate alternative to dipyridamole and adenosine for the diagnosis of coronary artery disease.
Adenosine Triphosphate↗
Inhibition of tumoral cell respiration and growth by nordihydroguaiaretic acid.
The effects of nordihydroguaiaretic acid (NDGA), best known as an inhibitor of lipoxygenase activities, on the culture growth, oxygen consumption, ATP level, viability, and redox state of some electron carriers of intact TA3 and 786A ascites tumor cells have been studied. NDGA inhibited the respiration rate of these two tumor cell lines by preventing electron flow through the respiratory chain. Consequently, ATP levels, cell viability and culture growth rates were decreased. NDGA did not noticeably inhibit electron flow through both cytochrome oxidase and ubiquinone-cytochrome b-c1 complex. Also, the presence of NDGA changed to redox state of NAD(P)+ to a more reduced level, and the redox states of ubiquinone, cytochrome b and cytochromes c + c1 changed to a more oxidized level. These observations suggest that the electron transport in the tumor mitochondria was inhibited by NDGA at the NADH-dehydrogenase-ubiquinone level (energy-conserving site 1). As a consequence, mitochondrial ATP synthesis would be interrupted. This event could be related to the cytotoxic effect of NDGA.
Adenosine Triphosphate↗
Adenovirus replication and transcription sites are spatially separated in the nucleus of infected cells.
We have visualized the intranuclear topography of adenovirus replication and transcription in infected HeLa cells. The results show that viral DNA replication occurs in multiple foci that are highly organized in the nucleoplasm. Pulse-chase experiments indicate that newly synthesized viral double-stranded DNA molecules are displaced from the replication foci and spread throughout the nucleoplasm, while the single-stranded DNA replication intermediates accumulate in adjacent sites. Double-labelling experiments and confocal microscopy show that replication occurs in foci localized at the periphery of the sites where single-stranded DNA accumulates. The simultaneous visualization of viral replication and transcription reveals that the sites of transcription are predominantly separated from the sites of replication. Transcription is detected adjacent to the replication foci and extends around the sites of single-stranded DNA accumulation. These data indicate that newly synthesized double-stranded DNA molecules are displaced from the replication foci and spread in the surrounding nucleoplasm, where they are used as templates for transcription. Splicing snRNPs are shown to co-localize with the sites of transcription and to be excluded from the sites of replication. This provides evidence that splicing of viral RNAs occurs co-transcriptionally and that the sites of viral DNA replication are spatially distinct from the sites of RNA transcription and processing.
Adenoviruses, Human↗
Enhanced protein blotting from PhastGel media to membranes by irradiation of low-intensity ultrasound.
A novel approach to protein blotting based on application of ultrasound is proposed. Three minutes of ultrasound exposure (1 MHz, 2.5 W/cm2) was sufficient for a very clear transfer of proteins from a polyacrylamide gel (PhastGel) to nitrocellulose or nylon 66 Biotrans membranes. The proteins evaluated were prestained sodium dodecyl sulfate-polyacrylamide gel electrophoresis standards (18,500-106,000 Da) and 14C-labeled Rainbow protein molecular weight markers (14,300-200,000 Da). In control experiments, which were performed following similar procedures without turning the ultrasonic generator on, no protein blotting could be seen. For comparable blotting results, 30 min for electroelution or 240 min for elution by convection blotting was required.
Electrophoresis, Polyacrylamide Gel↗
[Superiority of the reinjection method compared with the redistribution of thallium-201 in the evaluation of reversibility after myocardial infarction].
OBJECTIVE: To assess the relative capacity of thallium-201 reinjection (RI) and redistribution (RD) for detection of reversibility in patients after myocardial infarction. DESIGN: We prospectively studied patients referred to myocardial scintigraphy for viability evaluation with stress, redistribution and reinjection images. METHODS: Patients were studied with thallium-201 SPECT using three imaging acquisitions--stress, redistribution three to four hours later and reinjection 30-60 minutes after a second injection of thallium under nitroglycerin effect. Thallium uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments and a score obtained. Reversibility was classified as "definite" if the increase in thallium uptake was > or = 2 in a myocardial segment and as "possible" if the increase was one. PATIENTS: We studied 44 patients with previous myocardial infarction. RESULTS: The perfusion score after stress was 37.3 +/- 6.0, improving to 39.8 +/- 6.7 after redistribution and to 43.6 +/- 7.6 after reinjection (p < 0.02 between RD and RI). RD identified reversibility in 38% and RI in 63% (p < 0.001) of the 232 segments with perfusion defects. RI showed reversibility in 39% (definite in 25% and possible in 14%) of the 137 fixed perfusion defects in RD. For the detection of reversibility RI was superior to RD in all sub-groups analyzed. We found a relationship the degree of collateral circulation in the infarct related artery and the amount of reversibility in the infarcted area. CONCLUSIONS: These data suggest a clear superiority of reinjection over redistribution in thallium-201 scintigraphy for the detection of reversibility of perfusion defects after myocardial infarction, and must probably be considered as a routine procedure for myocardial viability assessment.
Adult↗
Assembly of snRNP-containing coiled bodies is regulated in interphase and mitosis--evidence that the coiled body is a kinetic nuclear structure.
Coiled bodies (CBs) are nuclear organelles in which splicing snRNPs concentrate. While CBs are sometimes observed in association with the nucleolar periphery, they are shown not to contain 5S or 28S rRNA or the U3 snoRNA. This argues against CBs playing a role in rRNA maturation or transport as previously suggested. We present evidence here that CBs are kinetic structures and demonstrate that the formation of snRNP-containing CBs is regulated in interphase and mitosis. The coiled body antigen, p80 coilin, was present in all cell types studied, even when CBs were not prominent. Striking changes in the formation of CBs could be induced by changes in cellular growth temperature without a concomitant change in the intracellular p80 coilin level. During mitosis, CBs disassemble, coinciding with a mitotic-specific phosphorylation of p80 coilin. Coilin is shown to be a phosphoprotein that is phosphorylated on at least two additional sites during mitosis. CBs reform in daughter nuclei after a lag period during which they are not detected. CBs are thus, dynamic nuclear organelles and we propose that cycling interactions of splicing snRNPs with CBs may be important for their participation in the processing or transport of pre-mRNA in mammalian cells.
Animals↗
Nuclear organization of splicing snRNPs during differentiation of murine erythroleukemia cells in vitro.
Murine erythroleukemia (MEL) cells are erythroid progenitors that can be induced to undergo terminal erythroid differentiation in culture. We have used MEL cells here as a model system to study the nuclear organization of splicing snRNPs during the physiological changes in gene expression which accompany differentiation. In uninduced MEL cells, snRNPs are widely distributed throughout the nucleoplasm and show an elevated concentration in coiled bodies. Within the first two days after induction of terminal erythroid differentiation, the pattern of gene expression changes, erythroid-specific transcription is activated and transcription of many other genes is repressed. During this early stage splicing snRNPs remain widely distributed through the nucleoplasm and continue to associate with coiled bodies. At later stages of differentiation (four to six days), when total transcription levels have greatly decreased, splicing snRNPs are redistributed. By six days postinduction snRNPs were concentrated in large clusters of interchromatin granules and no longer associated with coiled bodies. At the end-point of erythroid differentiation, just before enucleation, we observe a dramatic segregation of splicing snRNPs from the condensed chromatin. Analysis by EM shows that the snRNPs are packaged into a membrane-associated structure at the nuclear periphery which we term the "SCIM" domain (i.e., SnRNP Clusters Inside a Membrane).
Animals↗
[Reversibility in perfusion scintigraphy after myocardial infarct: a comparison between the protocol of single-day rest-stress with 99mTc sestamibi and reinjection with thallium-201].
OBJECTIVE: To compare thallium-201 stress-reinjection SPECT (TL) and single-day rest-stress 99mTc-sestamibi SPECT (MIBI) for detection of reversibility of perfusion defects after Q-wave myocardial infarction. DESIGN: Prospective study with the two scintigraphic methods. PATIENTS: We studied 31 patients with previous Q-wave myocardial infarction referred for assessment of myocardial viability. METHODS: Patients were studied with thallium-201 stress-reinjection SPECT and single-day rest-stress 99mTc-sestamibi SPECT. Tracer uptake was classified in a 0 to 4 intensity scale in each of 13 myocardial segments. RESULTS: Segmental comparison indicated that the identification of perfusion defects was similar by the two methods. Some reversibility was present in 51% of TL perfusion defects and in 26% of MIBI perfusion defects (p < 0.001). Twenty-seven percent of fixed perfusion defects in MIBI showed some reversibility by TL, but only 8% of the fixed perfusion defects by TL were reversible by MIBI (p < 0.001). In infarct-related perfusion defects, TL showed reversibility in 46% and MIBI in 22% (p < 0.001). TL detected reversibility in 84% of patients and MIBI in 48% (p = 0.007). CONCLUSIONS: Although the two methods were similar for perfusion defects identification, the present study suggests that thallium-201 reinjection is superior to single-day rest-stress 99mTc-sestamibi for the detection of reversibility. Clinical relevance of these differences, as a marker of viability, requires further evaluation of these patients after successful revascularization.
Adult↗
Extracorporeal enzymatic removal of low density lipoproteins in rabbits: efficacy and safety.
An extracorporeal circuit incorporating a plasma separator reactor (PSR) was designed to modify low density lipoproteins (LDL). The PSR was tested in vivo with hypercholesterolemic New Zealand White rabbits. The bioreactor enzymatically converts LDL to a form that can be removed by the body at an enhanced rate. The physiological response of hypercholesterolemic New Zealand White rabbits to 90 minute extracorporeal treatments was monitored. The total plasma cholesterol concentration in the treated rabbits fell sharply (up to 40% decrease) during and following the treatment. Results of safety tests indicate no significant enzyme leaching from the device, no disruption or damage to erythrocytes, no increase in white blood cell count and no liver damage as indicated by five enzyme assays. All safety measurements suggest that the treatment is safe.
Animals↗
The oxygen dependence of the mitochondrial respiration rate in ascites tumor cells.
The effect of the oxygen concentration on the rate of oxygen consumption by 786 and TA3 ascites tumor cell lines has been determined under steady-flow conditions with a membraneless fast-responding O2 electrode and using ascorbate and N,N,N',N'-tetramethyl-p-phenylenediamine as electron donors. The reaction was initiated by rapid injection of O2 into anaerobically incubated test system. The time-dependence of the intact cell respiration showed three distinct phases; an early very fast but short duration phase, a subsequent slow phase that prevailed for most of the reaction period and a third phase which preceded the reestablishment of anaerobiosis. Kinetic analysis of the reaction indicated a linkage between the catalytic efficiency and the transmembrane electrochemical potential. The rates of O2 uptake, obtained in the presence of both protonophores and ionophores, were monotonic and pseudo-first order over 90% of the course of O2 consumption. Extrapolation of the observed rates to zero time, at which zero delta mu H+ and thus constant flow prevails, was used to calculate the oxygen concentration for the half-maximal respiratory rate, which was found to be in the range 1.55-2.10 microM O2. No noticeable variation in the value of this kinetic parameter was found between the two cell lines used. Possible reasons for discrepancies in published reports on the oxygen dependence of the cytochrome c oxidase activity in various mitochondrial and reconstituted systems are discussed.
Animals↗
Effect of butylated hydroxyanisole on electron transport in rat liver mitochondria.
The effects of butylated hydroxyanisole (BHA), a commonly used food antioxidant, on oxygen consumption, ATPase activity, and the redox state of some electron carriers of rat liver mitochondria have been studied. It was observed that BHA slightly stimulated state 4 respiration but strongly inhibited ADP- and uncoupler-stimulated respiration on NAD(+)- and FAD-linked substrates. ATPase activity and vectorial H+ ejection were affected only slightly by BHA, suggesting that BHA predominantly inhibits mitochondrial electron flow. Experiments to determine its site of action showed that BHA did not noticeably affect electron flow through cytochrome oxidase; in contrast, NADH:duroquinone reductase activity and electron flow through ubiquinone-cytochrome b-cytochrome c complex were inhibited strongly because the oxidation of duroquinol was affected markedly. The BHA block of electron transport was bypassed by both N,N,N',N'-tetramethyl-p-phenylenediamine and 2,6-dichlorophenolindophenol. Also, the presence of BHA changed the redox state of cytochrome b and c1 to a more oxidized level. These observations suggest that electron transport is inhibited by BHA at the NADH-ubiquinone and at the ubiquinone-cytochrome b levels. From Hill plots, it is clear that more than one binding site is involved in complete inhibition; in addition, available evidence suggests that there may be two sites at the substrate side of ubiquinone and another two sites at the oxygen side of ubiquinone. Consequently, mitochondrial ATP synthesis would be interrupted. This event could be related to the toxicity of BHA.
Adenosine Triphosphatases↗
[Implanted venous access system in oncology. Review of 296 cases].
The authors present their experience of the use of a totally implanted vascular access system, at the Institut Jules Bordet. Between 1983 and 1988, 296 catheters were implanted in 289 patients. The average venous access period using this system was 232 days. The complication rate was only 0.36/1000 days of venous access. The totally implanted vascular system can provide a comfortable and reliable method of venous access in patients requiring prolonged intravenous chemotherapy.
Adolescent↗
t-butyl-4-hydroxyanisole as an inhibitor of tumor cell respiration.
The effect of t-butyl-4-hydroxyanisole (BHA), a widely used food antioxidant additive, on the culture growth, oxygen consumption, and redox state of some electron carriers of intact TA3 and 786A ascites tumor cells has been studied. BHA inhibited culture growth and respiration of these two tumor cell lines, by inhibiting the electron flow through the respiratory chain. Experiments to determine its site of action showed that BHA did not inhibit noticeably the electron flow through cytochrome oxidase, due to the ability of N,N,N',N'-tetramethyl-p-phenylenediamine to bypass the BHA inhibition of the respiration. Electron flow through the ubiquinone-cytochrome b-c1 complex also was unaffected by BHA; in fact, BHA failed to inhibit the oxidation of duroquinol. Spectrophotometric experiments are in accordance with studies carried out using synthetic electron donors. The redox state of NAD(P)+, determined in steady-state conditions, changed to a more reduced level, and the redox states of ubiquinone, cytochrome b, cytochromes c + c1 and cytochromes a + a3 changed to a more oxidized level. These observations suggest that the electron transport in the tumor mitochondria was inhibited by BHA at the NADH-dehydrogenase-ubiquinone level (energy-conserving site 1). These findings could explain, in part, the cytotoxic effect of BHA.
Animals↗
Local excision as conservative treatment for small rectal cancer.
Twenty patients with small rectal cancer, characterized by a well differentiated tumour localized within 10 cm of the anal margin, and by penetration limited to the submucosa or to the muscular layer, were treated by local excision. Four of them, who presented with a deep tumour invasion in the rectal wall, also received adjuvant radiation therapy. Our experience proves the reliability of the selection criteria for patients who may benefit from this procedure. They all stand a fair chance of cure and the quality of their lives will improve because local tumour excision avoids anal sphincter resection. Two patients had local recurrences and had to undergo further curative local excision. The two who died from their tumours and who had distant metastases were unsuitable for both local resection and other therapeutic procedure. Finally, there was no postoperative morbidity.
Adult↗