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Biomedical subjects

A Robert

Publications and source records attributed to A Robert.

At least 253 records · Page 14Linked to original sources
PubMed1990

[Semiology of HIV infection in children].

Human immunodeficiency virus infection is specific in children and related to their immune system. Recurrent bacterial and viral infections precede opportunistic infections. They are associated with non-specific manifestations (e.g. lymphadenopathy) and frequently reveal the HIV infection. Acute or chronic interstitial pneumonia is the main cause of morbidity and mortality (two-thirds of the cases); 34 to 90 p. 100 of children have neurological but also gastrointestinal and haematological involvement. All organs and systems can be directly or indirectly affected by the virus with immune and infectious consequences. The prognosis is very poor with an actuarial survival rate of 60 p. 100 at 5 years, so that strict clinical and laboratory monitoring is mandatory.

Adolescent↗
PubMed1990

Improvement in HPLC analysis of urinary trans,trans-muconic acid, a promising substitute for phenol in the assessment of benzene exposure.

Urinary trans,trans-muconic acid (t,t-MA), a minor metabolite of benzene, is a potential candidate for biological monitoring of benzene. A clean-up procedure using SPE extraction cartridges was applied to urinary samples in order to improve the reliability of t,t-MA determinations by HPLC-UV greatly and to carry out convenient analyses on a routine scale, particularly at low levels of t,t-MA concentrations. The detection limit of the method is low enough to measure urinary t,t-MA at a concentration of 0.05-0.1 mg/l. The recovery rates and relative standard deviations from spiked urines (1 mg/l to 20 mg/l) were about 90% and 5%, respectively. t,t-MA was found to be rapidly excreted by rats and humans. In rats the background range never exceeded 0.5 mg/l with a mean concentration around 0.3 mg/l. In 49 human blank urines, t,t-MA average and median-value were respectively around 0.2 and less than 0.1 mg/l with a range of less than 0.1 to 0.5 mg/l. Experimental exposure of rats for 1 h to 10.2 ppm of benzene induced urinary excretion of 13 mg/l of t,t-MA during a 6-h post-exposure period while occupational exposures to 2.6 ppm (mean exposure level during 5 d-8 h) and 7 ppm (4 h) of benzene resulted in urinary excretion of 2.1 (mean excretion level) and 6.5 mg/l respectively at the end of the exposure. In humans, t,t-MA has a similar half-time as phenol. Analysis of urinary t,t-MA seems to be a better indicator than phenol for the assessment of exposure to low levels of benzene. Ingestion of 200 mg of sorbic acid, the only other known precursor of t,t-MA, interfered minimally with the background excretion of t,t-MA.

Animals↗
PubMed1990

Additional prognostic value of exercise testing and thallium-201 scintigraphy in catheterized patients without previous myocardial infarction.

To determine whether exercise testing and thallium scintigraphy provide additional prognostic information in symptomatic patients undergoing catheterization, we studied 432 consecutive male patients without a previous myocardial infarction by means of an exercise test, thallium scintigraphy and catheterization. The follow-up period was 46 +/- 24 months (from 12 to 96). Events were defined as death (27 patients), nonfatal myocardial infarction (occurring in 27 patients) or late (greater than 60 days after test) surgery or dilatation (needed in 45 patients). The 5 year survival rate was 89% and the event-free rate was 72%. History, noninvasive and invasive variables were submitted to a stepwise Cox regression analysis. By multivariate analysis, the significant variables related to death were the number of diseased vessels and exercise workload; the selected variables for all cardiac events were the number of diseased vessels; the score at thallium exercise testing and exercise workload. Among the subgroups of 337 coronary patients, the predictive variables for death were exercise workload and the number of diseased vessels. For all cardiac events, the selected variables were the number of diseased vessels, the score of defects during thallium exercise and exercise workload. Thus, in patients without a previous myocardial infarction, noninvasive variables do provide prognostic information which is not available either from the history or from catheterization.

Cardiac Catheterization↗
PubMed1990

CSF drug levels for children with acute lymphoblastic leukemia treated by 5 g/m2 methotrexate. A study from the EORTC Children's Leukemia Cooperative Group.

A multicenter EORTC study was conducted in children with acute lymphocytic leukemia to determine whether 5 g/m2 of methotrexate (MTX) (24 h i.v. infusion, four cycles) is an appropriate dosage for obtaining CSF drug concentrations approaching the critical cytotoxic level of 10(-6) M. A total of 193 cycles were analyzed for 58 patients. At the end of the 24 h infusion, the mean MTX serum level was 65.27 +/- 33.11 microM; the mean CSF MTX level was 1.47 +/- 1.1 microM; no significant difference in CSF MTX levels was observed between patients with (n = 20) and those without i.v. Ara-C (n = 38). The mean CSF MTX/serum MTX ratio was 0.029 +/- 0.027. CSF drug concentrations greater than or equal to 10(-6) M were achieved in 81% of the courses. The highest level was 8.4 X 10(-6) M. Only 5% of patients failed to achieve this drug concentration in at least one cycle. No significant correlation was observed between blood and CSF MTX levels. Mean CSF MTX levels were comparable from one cycle to another.

Adolescent↗
PubMed1990

Detection of restenosis after successful coronary angioplasty: improved clinical decision making with use of a logistic model combining procedural and follow-up variables.

A prospective study of 111 patients who underwent repeat coronary angiography and exercise thallium-201 scintigraphy 6 +/- 2 months after complete revascularization by percutaneous transluminal coronary angioplasty was performed to assess whether clinical, procedure-related and postangioplasty exercise variables yield independent information for the prediction of angiographic restenosis after angioplasty. Complete revascularization was defined as successful angioplasty of one or more vessels that resulted in no residual coronary lesion with greater than 50% diameter stenosis. Restenosis was defined as a residual stenosis at the time of repeat angiography of greater than 50% of luminal diameter. Restenosis occurred in 40% of the patients. The 111 patients were randomly subdivided into a learning group (n = 84) and a testing group (n = 27). A logistic discriminant analysis was performed in the learning group and the logistic model was used to estimate a logistic probability of restenosis. This probability of restenosis was validated in the testing group. In the learning group of 84 patients univariate analysis of 39 factors revealed 8 factors related to restenosis: recurrence of angina (p less than 0.0001), postangioplasty abnormal finding on exercise thallium-201 scintigram (p less than 0.0001), exercise thallium-201 scintigram score (p less than 0.0001), difference between exercise and rest ST segment depression (p less than 0.001), postangioplasty exercise ST segment depression (p less than 0.001), absolute postangioplasty stenosis diameter (p less than 0.003), postangioplasty exercise work load (p less than 0.03) and postangioplasty exercise heart rate (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1990

Evidence for a modulatory role of protein kinase C on glycosaminoglycan biosynthesis during the spontaneous differentiation of Caco-2 cells.

The role of protein kinase C (PKC) in the regulation of glycosaminoglycan (GAG) sulfation was investigated during the spontaneous differentiation of Caco-2 cells. The total cellular activity of PKC as well as its subcellular distribution was examined from d 5 (non-differentiated cells) to d 15 (enterocytic differentiated cells): during this period, PKC was redistributed from the membrane to the cytosol, but the amount of PKC activity was not modified. This redistribution of PKC was concomitant with an increase in 35S-sulfate incorporation in GAG. 4-beta phorbol 12 beta-myristate, 13-alpha acetate (PMA) and 1-2 dioctanoyl-glycerol (DIC8), 2 PKC activators, decreased 35S-sulfate incorporation in GAG; by contrast, 4 alpha-phorbol 12,13 didecanoate (4 alpha-PDD), an inactive phorbol ester, proved to be ineffective. These results suggest that membrane-bound PKC which is the active form of the enzyme, may exert on GAG sulfation a modulatory role, which is gradually attenuated as Caco-2 cell differentiation progresses.

Biological Transport↗
PubMed1990

Area-at-risk determination by technetium-99m-hexakis-2-methoxyisobutyl isonitrile in experimental reperfused myocardial infarction.

In a canine model of reperfused myocardial infarction, we tested the hypothesis that after reperfusion, technetium-99m-hexakis-2-methoxyisobutyl isonitrile (Tc-MIBI) tomographic imaging still reflects occlusion blood flow when the tracer is injected before reperfusion. Nine anesthetized dogs underwent 2 hours of coronary occlusion followed by 3 hours of reperfusion ending by being killed. Reference coronary blood flow was determined by radioactive microspheres injected during occlusion and after reperfusion. Biopsies in normal and ischemic myocardium and single photon emission computed tomography were obtained during occlusion and after reperfusion. Circumferential profiles were applied to axial slices divided into 5-degree sectors. The sectors were divided into 3 groups selected on the occlusion acquisition (normal, mildly reduced, and severely reduced) and compared with the postreperfusion acquisition. Tissular Tc-MIBI kinetics was assessed both by Tc-MIBI time-activity curves of normal and ischemic tissue obtained by biopsy and by the relative gradient between normal, ischemic, and necrotic postmortem tissue samples. In biopsy samples, Tc-MIBI content remained unchanged during occlusion and after reperfusion in normal as well as in ischemic tissue (4,662 +/- 2,237 counts/min/mg vs. 4,599 +/- 1,577 counts/min/mg in normal tissue, NS; 941 +/- 903 counts/min/mg vs. 1,087 +/- 721 counts/min/mg in ischemic tissue, NS). In postmortem tissue samples, there was a good correlation between occlusion microsphere blood flow and Tc-MIBI activity (r = 0.91). In the necrotic samples, mean normalized Tc-MIBI activity (10 +/- 17%) was slightly higher than the normalized microsphere blood flow (3 +/- 3%, p less than 0.001) but markedly lower than the normalized microsphere reperfusion blood flow (63 +/- 31%, p less than 0.001). Comparing the single photon emission computed tomographic acquisitions before and after reperfusion, Tc-MIBI activity remained unchanged in normal as well as in mildly reduced or severely reduced segments. Thus, our data are consistent with the hypothesis that Tc-MIBI traces blood flow, does not redistribute significantly despite reperfusion, and can be used for imaging the area at risk.

Animals↗
PubMed1990

Cell surface alteration in Epstein-Barr virus-transformed cells from patients with extreme insulin resistance.

An abnormality was detected in the morphology of the cell surface of Epstein-Barr virus-transformed lymphocytes of patients with genetic forms of insulin resistance. In cells from two patients with leprechaunism and two patients with type A extreme insulin resistance, scanning electron microscopy demonstrated a decrease in the percentage of the cell surface occupied by microvilli in cells from the patients with leprechaunism and type A insulin resistance compared with control cells. When cells from a healthy control subject and one of the patients with leprechaunism (Lep/Ark-1) were incubated with 125I-labeled insulin, there was a decrease in the percentage of 125I-insulin associated with microvilli on the cell surface. Thus, the decreased localization of insulin receptors with the microvillous region of the cell surface was in proportion to the decrease in microvilli.

Autoradiography↗
PubMed1990

[Localized thoracic neuroblastoma: the role of surgery and therapeutic results. Apropos of 40 cases].

From 1982 to 1987, forty children with non-metastatic thoracic neuroblastoma were treated with a same therapeutic regimen. According to TNM staging, there were II CS I, 19 CS II and 10 CS III. All patients underwent surgery; thirty had primary surgical excision; in ten whose tumor were deemed uresectable, surgery was delayed until after a trial of chemotherapy. Operation was completed by several courses of chemotherapy in case of microscomic residual disease or lymph node involvement; radiotherapy was delivered in case of gross residual disease. Using this therapeutic approach. Event Free Survival is 92% with a median follow up of 40 months. Severe complications were rare and sequellae appear to be related to the disease i.e. neurologic consequence of cord compression.

Abdominal Neoplasms↗
PubMed1990

[Electrovectorcardiographic diagnosis of left ventricular hypertrophy in complete left bundle-branch block].

Diagnosis of left ventricular hypertrophy (LVH) in the presence of complete left bundle-branch block (CLBB) is difficult. The value of several electro-vectorcardiographic criteria were studied in a series of 71 patients with CLBB analyzed by echocardiography. Thirty nine of the patients (55%) had anatomical LVH defined as being a left ventricular weight (LVW) above 316 g. Twenty five of the 71 patients (35%) had dilated cardiomyopathy (dCMP). Of the hypervoltage indices, only the sum of RV6 + SV2 and the QRS spatial maximum vector (MAXQRSxyz) showed a significant difference between the group with LVH and the group without LVH. The duration of QRS and the average vector of spatial area (AQRSxyz) also differed significantly between the two groups and showed a good correlation with LVW. Of the various criteria for LVH, the best balance between sensitivity and specificity belonged to the criteria of duration of QRS greater than 150 msec and AQRSxyz greater than 140 mV.msec, with a merit ratio of 0.44 and a diagnostic accuracy of 72 per cent. In the dCMP subgroup, all the voltage and duration indices were significantly different between the two groups. The criterion AQRSxyz greater than 135 mV.msec obtained the best diagnostic score, with a sensitivity of 94 per cent, specificity of 100 per cent, and accuracy of 96 per cent. This parameter gave the best overall expression of the combination of hypervoltage and delay in ventricular depolarization produced both by hypertrophy/ventricular dilation and conduction disturbances.

Aged↗
PubMed1990

[Infectious complications of the treatment of acute lymphoblastic leukemia in children].

The authors report the infectious complications observed during the treatment of acute lymphoblastic leukemia in 70 children, followed by a same team, with the same protocole, for a period of 6 years (mean follow-up: 42.3 months). The complications were mainly bacterial during induction phase, mainly staphylococcic the microbiological follow-up and a rapid empiric antibiotic therapy allowed to control more than 80% of the febrile episodes. There was one death from fulminant pyocyanic infection.

Adolescent↗
PubMed1990

Methodology of ECG interpretation in the Louvain program.

The Louvain program performs the analysis and interpretation of the vectorcardiogram (VCG) to increase the clinical utility of ECG analysis. Among its original features, there are (1) a high-resolution vector-loop display for visual analysis, (2) quantitative analysis of the spatial VCG using age-sex stratified limits, (3) separate software for adult and pediatric series and (4) complementary deterministic and statistical methods of diagnostic classification. Using objective, ECG-independent evidence as a reference standard, the Louvain program has shown satisfactory levels of diagnostic accuracy in most basic categories. However, its usefulness is especially marked in "borderline" or "complex" situations, where the 12-lead ECG cannot provide a clear answer. It corresponds to the concept of "computer-assisted ECG interpretation" as opposed to "computer ECG analysis".

Adult↗
PubMed1990

[Prospective study of HIV infection in a group of 30 young hemophiliacs].

In order to investigate the progression to AIDS, we studied 39 patients with hemophilia ranging presently in age from 8 to 20 years, who had been positive for HIV antibodies for a mean of 36 months. Every 3 to 6 months a clinical and laboratory examination was performed. The number of patients with AIDS increased from 2 to 6 and 2 patients died from opportunistic infections. The percentage of patients with less than 500 T4 cells increased from 28% to 41%. Increase in serum IgA concentrations above 2.5 gl/l ranged from 23% to 38% of patients. Seven subjects were found to be positive for HIV antigen and 11 of 15 had a loss of p24 antibody. Patients' distribution into two groups according to the results of T4 cells count at the beginning of the study have shown a significant difference on the basis of clinical and biological progression. The present investigation confirms the progression in this population and the importance of some markers.

Acquired Immunodeficiency Syndrome↗
PubMed1990

[Correlation of the vectorcardiographic, echocardiographic parameters and hemodynamics in valvular aortic stenosis].

The objective of this work was to verify the correlation between haemodynamic (KT), echocardiographic (ECHO) and vectorcardiographic (VCG) parameters in valvular aortic stenosis (VAS). The VCG was analyzed by the Louvain programme and compared with reference ECHO and KT parameters--transvalvular peak-gradient (PG), mean gradient (MG) and valvular area (AREA)--in 54 consecutive patients with isolated VAS. Of the 84 correlations studied, only three proved to be significant for linear parameters and six for angular parameters. The best correlation was observed between the azimuthal angle of the spatial area vector of the QRS loop and MG-KT (r2 = 0.36, p less than 0.01). On the other hand, there was no significant correlation between the reference parameters and the amplitude of the QRS spatial maximum vector. The conclusion was drawn that there was no linear correlation between the VCG indicators of LVH and ECHO and KT indices of severity in an unselected VAS population. Each method carries its own limitations and each must be used as a complement to other methods.

Aged↗
PubMed1989

Changes in glycosaminoglycan sulfation and protein kinase C subcellular distribution during differentiation of the human colon tumor cell line Caco-2.

During the spontaneous differentiation (day 5 to day 15 of the culture) of Caco-2 cells, the sulfation of cell layer glycosaminoglycans increased, whereas protein kinase C activity was concomitantly redistributed from the membrane to the cytosol. The protein kinase C activators, 4 beta-phorbol 12 beta-myristate, 13 alpha-acetate and 1,2-dioctanoylglycerol inhibited glycosaminoglycan sulfation. By contrast, 4 alpha-phorbol 12, 13 didecanoate was ineffective. These results suggest that membrane-bound PKC may exert a modulatory effect on glycosaminoglycan sulfation, and this effect is gradually attenuated as Caco-2 cell differentiation progresses.

Cell Differentiation↗