[Bone scintigraphy in evaluation of bone vascularisation at wrist and hand]. / La scintigraphie osseuse dans l'évaluation de la vascularisation osseuse au niveau de la main et du poignet.

Diphosphonate bone scintigraphy is used since the 1970s for studying bone pathology; it is increasingly common because of increased physical activity of the population. The disphosphonate uptake in bone requires the preservation of bone vascularity and reflects osteoblastic activity; it allows studying the viability of bone. Using data from the literature and our experience, we tried to take stock of its main uses in routine emphasizing the study of vascular and describe its use in fractures of the scaphoid and in the study of vascularised bone transfers. If the value of scintigraphy is well known, the use made by means of pinhole collimator and the market entry of new and more sensitive detectors with better resolution could allow the side of the imaging anatomy of improving the study of the vascularisation of small bone transfers which are increasingly used, particularly at wrist and hand.

Synthesis of Nepsilon-protected-L-lysine and gamma-benzyl-L-glutamate N-carboxyanhydrides (NCA) by carbamoylation and nitrosation.

This paper reports on an original process to synthesize N-carboxyanhydrides, which consists of nitrosating N-carbamoylamino acids with a NO/O(2) gas mixture in acetonitrile. The synthesis of several N-carbamoylamino acids of L-lysine was described using potassium cyanate in water. The latter were then nitrosated to yield the corresponding NCA with more or less efficiency. Indeed, the NCA carrying an acid-sensitive protecting group led to a partial deprotection to give the L-lysine NCA salt. The NCA of N(epsilon)-trifluoroacetyl-L-lysine, N(epsilon)-benzyloxycarbonyl-L-lysine and gamma-benzyl-L-glutamate were successfully synthesized with satisfactory yields. Their polymerizability was compared to that of the N(epsilon)-trifluoroacetyl-L-lysine NCA initiated by n-hexylamine in N,N-dimethylformamide. It also showed that this new process of NCA synthesis could be applied to the synthesis of polypeptides and more generally to the protein chemistry.

N-carbamoyl amino acid solid-gas nitrosation by NO/NOx: A new route to oligopeptides via alpha-amino acid N-carboxyanhydride. Prebiotic implications.

Alpha-N-Carbamoyl amino acid (CAA), whose conditions of formation in a prebiotic hydrosphere have been described previously (Taillades et al. 1998), could have been an important intermediate in prebiotic peptide synthesis through reaction with atmospheric NOx. Nitrosation of solid CAA (glycine or valine derivative) by a 4/1 NO/O2 gaseous mixture (1 atm) yields N-carboxyanhydride (NCA) quantitatively in less than 1 h at room temperature. The crude solid NCA undergoes quantitative oligomerization (from trimer to nonamer under the conditions we used) when treated with a (bi)carbonate aqueous buffer at pH 9. We therefore suggest that part of the prebiotic amino acid activation/polymerization process may have taken place in a dry phase ("drying-lagoon" scenario).

Semi-automatic segmentation of gated blood pool emission tomographic images by watersheds:application to the determination of right and left ejection fractions.

Tomographic multi-gated blood pool scintigraphy (TMUGA) is a widely available method which permits simultaneous assessment of right and left ventricular ejection fractions. However, the widespread clinical use of this technique is impeded by the lack of segmentation methods dedicated to an automatic analysis of ventricular activities. In this study we evaluated how a watershed algorithm succeeds in providing semi-automatic segmentation of ventricular activities in order to measure right and left ejection fractions by TMUGA. The left ejection fractions of 30 patients were evaluated both with TMUGA and with planar multi-gated blood pool scintigraphy (PMUGA). Likewise, the right ejection fractions of 25 patients were evaluated with first-pass scintigraphy (FP) and with TMUGA. The watershed algorithm was applied to the reconstructed slices in order to group together the voxels whose activity came from one specific cardiac cavity. First, the results of the watershed algorithm were compared with manual drawing around left and right ventricles. Left ejection fractions evaluated by TMUGA with the watershed procedure were not significantly different (p=0. 30) from manual outlines whereas a small but significant difference was found for right ejection fractions (p=0.004). Then right and left ejection fractions evaluated by TMUGA (with the semi-automatic segmentation procedure) were compared with the results obtained by FP or PMUGA. Left ventricular ejection fractions evaluated by TMUGA showed an excellent correlation with those evaluated by PMUGA (r=0. 93; SEE=5.93%; slope=0.99; intercept = 4.17%). The measurements of these ejection fractions were significantly higher with TMUGA than with PMUGA (P<0.01). The interoperator variability for the measurement of left ejection fractions by TMUGA was 4.6%. Right ventricular ejection fractions evaluated by TMUGA showed a good correlation with those evaluated by FP (r = 0.81; SEE = 6.68%; slope = 1.00; intercept = 0.85%) and were not significantly different (P = 0.42). The interoperator variability with TMUGA was 6.7% for the right ventricle. Thus, the watershed algorithm proposed is an efficient segmentation tool for the semi-automatic analysis of right and left ventricular ejection fractions by TMUGA. Further studies are necessary to check whether this procedure can be used to evaluate ventricular volumes and cardiac outflow.

Dopaminergic influence on cardiovascular responses to exercise stress in hypertensive subjects.

Ten hypertensive subjects were studied at the Vargas Medical School in Caracas, Venezuela. They were submitted to submaximal treadmill exercises according to Bruce's protocol under treatment with dopaminergic drugs (metoclopramide, bromocriptine). Before and during submaximal exercises, metoclopramide caused a hypotensive effect accompanied by an increased heart rate, which was blocked by the administration of bromocriptine. We conclude that a probable dopaminergic modulatory influence takes place during exercise.

Efectividad terapéutica y tolerancia de una nueva formulación de nifedipina para ser administrada una vez al día, en forma de micropartículas / Therapeutic effectiveness and toleration of a formulation new of nifefipine to be administrate one turn day in form of microparticles

Se evaluó la efectividad y tolerancia de una nueva formulación de Nifedipina en forma de micropartículas de administración una vez al día en 23 pacientes con hipertensión arterial sistémica leve y moderada. En los resultados se apreció un descenso significativo de ambas presiones. El descenso en la presión sistólica fue de 15 por ciento (P<0.001) y en la diastólica de 17 por ciento (P<0.001) sin incrementos en la frecuencia cardíaca. El 83 por ciento de los pacientes normalizaron sus cifras de presión arterial y en 95 por ciento del total de los pacientes tratados se logró un importante descenso de las mismas. El producto fue bien tolerado, un sólo paciente presentó efectos secundarios leves atribuídos al medicamento en estudio

Severity of asthma is related to endotoxin in house dust.

In sensitized subjects, exposure to the mite allergen appears to be only one of several factors leading to asthma. We hypothesized that in association with allergen exposure, endotoxin, a proinflammatory agent present in house dust (HD), influences the severity of asthma. Using a cross-sectional study design, we investigated a group of 69 consecutive dust mite (HDM)-sensitized subjects defined as having rhinitis (n = 20) or asthma (n = 49); the latter were evaluated functionally and clinically by three different scores and by their need for daily medication. Concentrations of Dermatophagoides pteronyssinus p I allergen (Der p I) (by two-site monoclonal antibody enzyme-linked immunosorbent assay [ELISA]), guanine (by high-pressure liquid chromatography [HPLC]), and endotoxin (by modified Limulus. amebocyte lysate assay) were measured in HD collected in duplicate from the mattresses and floors in each subject's home. The concentrations of Der p I and of guanine in HD collected from mattresses were significantly higher in asthmatic subjects than in those with rhinitis (p < 0.05 and < 0.04, respectively). In subjects (n = 37) exposed to a high level of HDM allergen (i.e., Der p I > or = 10 micrograms/g HD and/or guanine > or = 0.10 mg/100 mg HD), the severity of asthma was unrelated to mite allergen concentration in HD. On the contrary, the severity of asthma was related to concomitant exposure to endotoxin in HD, since the concentration of HD endotoxin was significantly and inversely correlated with FEV1 (p < 0.05), FEV1/FVC (p < 0.02), daily need for oral (p < 0.01) and inhaled (p < 0.01) corticosteroids, daily need for beta 2 agonists (p < 0.001) and xanthines (p < 0.01), and clinical scores such as the modified Aas score (p < 0.01). In HDM-sensitized subjects exposed to a high level of allergen, the concentration of endotoxin measured in HD is an important determinant of asthma severity.

Mechanism of action of maternal serum on the interleukin2 receptor expression.

Neoplastic Jurkat cells were submitted to a PHA stimulation test after a preincubation in maternal or nulliparous serum (10% dilution). The Il2R expression was significantly downregulated among maternal serum treated cells. Retroplacental serum was significantly more inhibitive than peripheral maternal serum (P less than 0.01). The maternal IgG fractions and mostly the retroplacental IgG fraction proved to contain a factor mainly responsible for the Il2R expression inhibitive property. The molecular mechanism of this phenomenon was further studied. It was shown that H7 (acting as a protein kinase inhibitor) could not influence the Il2R modulation. E.G.T.A., a calcium chelator, was not able to interfere with the inhibitive influence of maternal serum. It was suggested that the maternal serum mediated inhibition of the IL2R expression is not influenced by the hydrolysis of membrane bound phosphatidyl inositol. In contrast, pertussis toxin markedly enhanced, in a dose dependent way, the suppressive influence of maternal serum as compared to nulliparous serum. At low concentrations, pertussis toxin lost its stimulating property and retained its ability to ADP ribosylate the alpha subunit of G proteins inducing a release of adenylcyclase mediating cAMP synthesis. This mechanism has been further studied by the addition of dbc AMP or dbc GMP to Jurkat cells preparations stimulated by PHA. dbc AMP, in a dose-related way, induced a downregulation of the IL2R expression of stimulated neoplastic cells preincubated in nulliparous or maternal serum. dbc GMP did not influence the IL2R expression in the same experimental conditions. The maternal serum mediated cells showed the most pronounced IL2R inhibition. Finally, it was shown that the cAMP synthesis by PHA stimulated Jurkat cells was upregulated in a dose dependent way, after a previous cellular incubation in progressive concentrations of maternal serum. In contrast, among nulliparous serum pretreated cells, cAMP synthesis remained significantly lower, after a lectin stimulation, as compared to the cAMP production derived from retroplacental serum treated and stimulated cells. Taken together, these experiments suggest that the maternal serum dependent suppression of the IL2R expression is related to a protein G stimulation followed by an enhanced cAMP synthesis.

Modulation of B cell stimulation by maternal serum.

Anti-IgM stimulation of B cells is decreased in the presence of maternal serum as compared to control media. This inhibiting influence of maternal serum is observed during the priming of the B cells. The progression of B cells into cellular proliferation was not influenced by maternal serum. At the level of the immunoglobulin secretion, the influence of maternal serum was also shown. A significant down regulation of the IgM, no change of the IgG production, and an enhanced secretion of IgA and IgE was demonstrated in the presence of maternal serum as compared to control media. It has been suggested that the maternal IgG fraction contains a molecule partly responsible for these changes. Furthermore, the CD23 antigen is increased when B cells are stimulated in the presence of a pool of maternal IgG. All the findings concerning maternal IgG were more pronounced when retroplacental IgG was used instead of peripheral maternal IgG. This observation suggests that the factor responsible for the B cell changes is released at the fetomaternal interface.

pH monitoring for 24 hours of gastroesophageal reflux and gastric function after intrathoracic gastroplasty after esophagectomy.

Gastroesophageal reflux is the main complaint after intrathoracic gastroplasty for carcinoma of the esophagus. Eighteen patients who underwent intrathoracic gastroplasty were studied by 24 hour pH monitoring. Two groups of patients were separately evaluated according to the surgical procedure performed--group 1, nine patients with tubulized stomach and gastroesophageal anastomosis at the apex of the thorax, and group 2, nine patients without tubulized stomach and with low gastroesophageal anastomosis. Gastroesophageal reflux and gastric function were analyzed. Gastroesophageal reflux was clinically present in 36 per cent of patients. During the 24 hour pH monitoring period, the percentage of time that the esophageal electrode showed a pH value of less than 4 was shorter for group 1 than for group 2 (13.3 +/- 11.3 versus 32.7 +/- 21.7), indicating less gastroesophageal reflux. Gastric secretion was also studied with 24 hour pH monitoring. Gastric secretion was reduced after gastroplasty, compared with a control group. Gastric secretion was identical between groups 1 and 2. Tubulization did not impair gastric secretion. Findings from this study show that good functional results can be achieved after intrathoracic gastroplasty if the anastomosis is performed on the neck or at the apex of the thorax. This technique can reduce gastroesophageal reflux without an antireflux procedure.

The interleukin-2 receptor on cord blood and nulliparous mononuclear cells is downregulated by maternal and cord blood serum.

The concentration of interleukin-2 receptor (IL-2R) on maternal, cord blood and unrelated nulliparous mononuclear cells has been studied after a previous phytohaemagglutinin (PHA) stimulation. Furthermore, the inhibitive action of maternal and cord blood serum on the IL-2R expression of stimulated nulliparous and cord blood lymphocytes has been shown. A downregulation of the [3H]-thymidine uptake by these PHA treated cells previously incubated in maternal and cord blood serum has been observed. Retroplacental serum was the most inhibitive experimental medium. The IL-2R modulation property of maternal serum has been studied during the pregnancy. Appearing quite early (in the sixth week), the maternal serum dependent inhibitive factor vanished, 2 to 3 weeks after delivery. After a study of the different serum components, it is suggested that the IL-2R downregulating molecule is included in the maternal immunoglobulin (IgG) fraction. Further experiments suggest that the addition of recombinant IL-2 during the action of low doses of maternal IgG allows a partial re-expression of the IL-2R. However, at physiological concentrations of IgG, the IL-2R downregulation becomes irreversible.

Modulation of class II histocompatibility antigen expression by maternal serum.

Human maternal serum has been shown to down-regulate the expression of MHC class II antigen in three distinct circumstances. Cord blood mononuclear cells, incubated in the mother's own serum, showed significant modulation of class II antigen expression. This was also the case for unrelated donor lymphocytes, incubated in pooled maternal serum. One neoplastic line (Daudi) was further shown to down-regulate class II antigen expression. In this last case, the down-regulating effect persisted over a 10-day period during which maternal serum was renewed regularly. Retroplacental serum was more MHC class II-inhibiting than peripheral serum. This down-regulating effect does not apply to maternal lymphocytes. The inhibitory effect is thought to be due to a factor, yet to be defined, included in the maternal IgG fraction. Regular assays made throughout pregnancy showed that the class II inhibiting component appears early (5th week), reaches its peak value at the 12th week, and disappears 2 or 3 weeks after delivery.

Modulation of the interleukin 2 receptor by maternal and cord blood serum.

In this report, the potential inhibitive action, of maternal serum (retroplacental and peripheral), and cord blood serum on the expression of the Il2r has been studied. Calf and male serum were used as a control. In order to have an optimal Il2r expression, a previous PHA cellular stimulation was performed. The maternal serum's Il2r inhibitive property was measured during and after the pregnant period. The presence of Il2r on maternal lymphocytes, cord blood cells, and unrelated donor mononuclear cells has been investigated (after a PHA stimulation assay). The downregulated Il2r expression of neoplastic cell line (Hut78 cell line) under the influence of maternal serum has been observed. The examination of the inhibitive action due to maternal serum has suggested that a factor included in the IgG fraction is mainly responsible for the downregulating property concerning the Il2r expression. A possible mechanism for the action of this factor has been studied. Further experiments suggest that the addition of recombinant Il2 during the action of low doses of maternal IgG allows a partial reexpression of the Il2 receptor. However, at physiological concentrations of IgG, the Interleukin 2 receptor downregulation becomes irreversible.

Functional modifications of the CD4+ and the CD8+ subset due to maternal serum.

Numerous experiments have been performed to try to explain the successful gestation of the semiallogeneic mammalian fetus in the immuno-competent mother. A popular hypothesis is that localized intra uterine suppression mediates the immune response and contributes directly to the survival of the fetus. Suppressive factors synthesized at the fetomaternal interface may be transported by the bloodstream and be found in the retroplacental and peripheral blood circulation. In this report we aim to study these modulating factors by exposing a proteinaceous antigen (Candidine or human mono nuclear cells) to unrelated human lymphocytes in the presence of a pool of maternal serum, retroplacental (MAT SR) or peripheral (MAT SP), or to a pool of male or calf serum (MALS or CS). A significant downregulation of the candidine mediated lymphocytic stimulation was observed in the case of the maternal serum. In order to further characterize this inhibition, a quantitative evaluation of the expression of the CD4 and CD8 positive subpopulations was performed. A selective inhibition of the CD4 positive subset was observed. In the PHA stimulation assay in the presence of maternal serum there was an inhibition of the thymidine uptake of unrelated lymphocytes. When studying the different subsets which were stimulated in the presence of maternal serum and control media it was shown that the CD4 positive subpopulation remained unchanged while there was a slight inhibition of the CD8 positive subset in the first case (maternal serum treated). The same CD4 positive inhibitive property of maternal serum was observed when a neoplastic cell line (HUT cells) was used as target for candidine in a stimulation test. This CD4 inhibited expression remained constant as long as the maternal serum was renewed. Maternal lymphocytes however remained resistant to the inhibitive action of maternal serum and did not show any change in their CD4 and CD8 positive subpopulation. By investigating the different blood components, it was shown that the suppressive factor was included in the IgG fraction and synthesized at the placental level. Appearing quite early during the gestation (at the 5-6th week), this factor was vanishing 2 weeks after the delivery.

Estimation of hepatic volume by SPECT during liver regeneration: an experimental study in an animal model.

To calculate hepatic volume in the dog by single photon emission computerized tomography (SPECT), we determined the limits of the organ by choosing an isocontour on each section. This choice entailed prior calculation of an overestimated pseudovolume. The accuracy of the measurement in the animal then approached that of measurements in vitro. We used the method to monitor hepatic regeneration in the dog after 65% hepatectomy and detected oedema and postoperative trauma, and over a longer timespan, stagnation of regeneration and a secondary drop in hepatic volume.

Single photon emission computerized tomography (SPECT) for monitoring regeneration of the human liver after partial hepatectomy for secondary tumours.

In 18 patients, the liver volume during regeneration after partial hepatectomy for secondary tumours was estimated by single photon emission computerized tomography (SPECT). Hepatic weight index (HWI) was subsequently calculated to follow evolution of the regeneration as a function of postoperative complications over a 30-day period. In patients with postoperative complications the HWI curves initially rose progressively and either reached a plateau or declined thereafter. The same pattern of HWI evolution was observed in patients with tumour recurrence, which was diagnosed later. On the other hand, in patients without postoperative complications the HWI curves rose continuously. These findings showed that a regenerative response was not the same in patients with or without postoperative complications; whereas in patients with tumour recurrence it could additionally provide prognostic information.

[Esophageal scintigraphy and pH measurement in asthmatic adults suspected of having gastroesophageal reflux]. / Scintigraphie et pHmétrie oesophagienne chez des adultes asthmatiques suspects de reflux gastro-oesophagien.

Fifty-five adults with asthma were explored by gastroesophageal scintigraphy (GES) and pH monitoring (3 postprandial hours, 12 nocturnal hours). For their asthma, all patients received theophylline twice a day. Associated digestive symptomatology led to investigations for gastroesophageal reflux (GER). Twelve hours pH monitoring, the reference method, was validated in 13 normal volunteers. During 12 hr pH monitoring, 4 criteria were studied: number of GER, percentage of time at pH 4, number of GER longer than 5 min and longest GER. Acid reflux occurred in 69 p. 100 of cases. Three hours postprandial pH monitoring and GES showed a GER in 40 and 47.5 p. 100 of cases (p greater than 0.05). GES revealed pulmonary aspiration in almost a quarter of asthmatic adults. Detection of a 30 p. cent increment of nocturnal GER by long pH monitoring could explain that results may differ with various techniques. Pulmonary aspiration was more frequent after longer and deeper GER. The mean duration of GER was more than 9 min but it was not significantly different from GER without pulmonary aspiration. GES may be helpful after 12 h pH monitoring because it can prove pulmonary aspiration. Its association with long and intense GER at 12 h pH monitoring suggests definitive surgical treatment of GER in asthmatic patients.

Variación de uratos sericos en pacientes con infartos miocárdico durante la fase aguda / Urates serum changes in patients with myocardiol infarction during acute phose

Estudiamos un grupo de 32 pacientes, de los cuales 25 eran varones y 7 fueron hembras, con un rango de edad entre 39 y 85 años. A quienes se les diagnosticó infarto miocárdico agudo (IMA) según criterios clínicos electrocardiográficos y enzimáticos. Les fueron practicadas determinaciones de uratos séricos en las primeras 24 horas, 48 horas, 72 horas y posteriormente a las 6 semanas. Encontramos una clara tendencia a na elevación de los uratos séricos durante la fase aguda y descenso posterior de los mismos. Esta tendencia fue comparable en el grupo que cursó con valores de uratos séricos dentro del rango de lo normal. Una asociación con uremia encontramos en el grupo de pacientes que cursaron con valores de uratos séricos elevados. Mayor morbilidad y mortalidad en el grupo de pacientes que cursó con valores de uratos séricos elevados en las primeras 24 horas, al compararlos con el grupo de pacientes normouricémicos en el mismo momento. Concluimos: Los uratos se elevan y descienden durante el IM; La hiperuricemia sin uremia es inusual en infarto. El ácido úrico fue signo de mal pronóstico cuando se asoció en las primeras 24 horas del IM. Sugerimos que el ácido úrico tiene importancia pronóstica en IMA

In vitro influence of thymopentin on proliferative responses and phytohemagglutinin-induced interleukin 2 production in normal human lymphocyte cultures.

Peripheral human blood lymphocytes from healthy blood donors were investigated in vitro to observe the influence of different doses of thymopentin on nonstimulated proliferation, candidin-stimulated proliferation, and phytohemagglutinin (PHA)-induced interleukin 2 (IL2) production. Concentrations of thymopentin ranging from 0.01 to 10,000 ng/ml were used. The proliferation response in non-stimulated cultures was significantly higher in the presence of 0.01, 1, 10, 1,000, and 10,000 ng/ml of thymopentin. There was no significant increase with 0.1 or 100 ng/ml of thymopentin. Thus, three separate peaks were present in these unstimulated cultures: at a concentration of 0.01 ng/ml; between 1 and 10 ng/ml, and between 1,000 and 10,000 ng/ml. These peaks possibly represent three different subpopulations with different sensitivities to different concentrations of thymopentin. Candidin-induced proliferation was significantly higher only at concentrations of 1 and 10 ng/ml of thymopentin, corresponding to the second peak in the unstimulated culture. No other thymopentin concentrations induced significant increase in the candidin-stimulated cultures. No IL2 production was observed in the unstimulated cultures, even in the presence of thymopentin. On the contrary, preincubation with different concentrations of thymopentin influenced PHA-induced IL2 production. A significant increase in the IL2 level was observed in the supernatant of the cultures if 1,000 ng/ml of thymopentin was used in the preculture period. This concentration corresponds to the third peak in the unstimulated cultures. No significant changes were observed with other concentrations of thymopentin. As the measured value of IL2 is a result of a balance between IL2 production and utilization, the above-mentioned findings need further investigation.(ABSTRACT TRUNCATED AT 250 WORDS)