Search PubMed⌕ Search

Biomedical subjects

P Colonna

Publications and source records attributed to P Colonna.

At least 55 records · Page 3Linked to original sources
PubMed1996

Analysis of microvascular integrity, contractile reserve, and myocardial viability after acute myocardial infarction by dobutamine echocardiography and myocardial contrast echocardiography.

The purpose of this study was to evaluate, in postinfarction dysfunctioning myocardium, the relative potential of myocardial contrast and low-dose dobutamine echocardiography in detecting myocardial viability, and the relation between microvascular integrity, contractile reserve, and functional recovery at follow-up. Twenty-four patients with recent myocardial infarction were studied before hospital discharge with low-dose dobutamine and myocardial contrast echocardiography. In the dysfunctioning infarct area, wall motion score index was calculated at baseline, during low-dose dobutamine, and at 3-month follow-up. Revascularization of the infarct-related artery was performed if clinically indicated. Eighteen patients (group A) had myocardial enhancement of the dysfunctioning infarct area at myocardial contrast echocardiography of >50%, whereas the remaining patients (group B) had an increase of < or = 50%. Wall motion score index was similar at baseline in groups A and B (2.6 +/- 0.4 and 2.8 +/- 0.2; p = NS), but it improved during low-dose dobutamine and at follow-up only in group A (1.9 +/- 0.9 and 1.9 +/- 0.7, respectively; p <0.001 vs baseline). In group B, wall motion score index was 2.7 +/- 0.4 with low-dose dobutamine and 2.8 +/- 0.2 at follow-up (p = NS vs rest). In identifying viable myocardial segments, myocardial contrast echo had 100% sensitivity and 46% specificity, whereas low-dose dobutamine echo had 71% sensitivity and 88% specificity. Thus, microvascular integrity after acute myocardial infarction is a fundamental prerequisite for ensuring myocardial contractile reserve and regional functional recovery. Myocardial contrast and low-dose dobutamine echocardiography have different, but complementary, diagnostic characteristics in detecting myocardial viability.

Aged↗
PubMed1996

Molecular weight distribution of amylose fractions obtained by aqueous leaching of corn starch.

Ultracentrifugation was used to clarify seven amylose fractions obtained by aqueous leaching of corn starch by 5 degrees C steps over a temperature range of 65-95 degrees C. Each fraction was characterized by its hydrodynamic radius R-(H), as determined by dynamic light scattering--and by the macromolecular features (M-(W), the weight-average molecular weight; R-(G), the z-average gyration radius, MWD, the molecular weight distribution) determined by size-exclusion chromatography coupled on line with multi-angle laser light scattering using 0.1 M KOH as solvent. This procedure provided new insights into the leaching process. In particular, a key temperature (85 degrees C) was noted, after which amylose M-(W) increased markedly from 8 x 10(4) - 1.4 x 10(5) to 3 x 10(5) - 3.5 x 10(5) g.mol(-1). Molecular weight dependences of macromolecular sizes were consistent with the behaviour of an expanded chain in good solvent with in particular a hydrodynamic coefficient v within the 0.6-0.7 range for the R(G) approximately M(v) relation. Finally, a method was developed to fit corresponding experimental molecular weight distributions with mathematical distributions of two populations. This enable us to determine that the molecular weight distribution for each leached amylose fraction was at least bimodal and to calculate the corresponding M(W) to each component.

Amylose↗
PubMed1996

Mediastinal tumor size and response to chemotherapy are the only prognostic factors in supradiaphragmatic Hodgkin's disease treated by ABVD plus radiotherapy: ten-year results of the Paris-Ouest-France 81/12 trial, including 262 patients.

PURPOSE: To identify prognostic factors in 262 patients with supradiaphragmatic Hodgkin's disease (HD), clinical stages (CS) I and II, prospectively treated between 1981 and 1988 according to the Paris-Ouest-France (POF) 81/12 protocol by three 1-month cycles of doxorubicin, bleomycin, vinblastine, and dacarbazine plus methylprednisone (ABVD-MP) followed by subtotal nodal irradiation (RT). PATIENTS AND METHODS: The size of mediastinal tumor (MT) was measured in all patients: 66 did not have MT (NoMT); 105 had a small-size MT (SSMT), ie, mediastinal mass ratio (MMR) less than 0.33; 58 had a medium-size MT (MSMT), ie, MMR > or = 0.33 and less than 0.45; and 33 had a bulky MT (BuMT), ie, MMR > or = 0.45. All patients received three cycles (CS IA, one cycle only) of ABVD-MP; patients in partial remission (PR) or complete remission (CR) after chemotherapy (CT) received supradiaphragmatic RT (involved fields, 40 Gy; adjacent fields, 30 Gy) plus lumboaortic and splenic RT (30 Gy); patients not in CR or PR after CT received salvage CT. RESULTS: Two hundred seventeen patients (82.8%) entered CR after CT and 258 (98.5%) after RT. Ten-year freedom-from-progression (FFP) and survival rateswere 88.6% and 89.4%, respectively. According to univariate analysis, MT size and post-CT status were the only factors to influence both FFP and survival. For patients with NoMT or SSMT, those with MSMT, and those with BuMT, FFP rates were 94.1%, 87.0%, and 63.0% (P < .001), respectively, while corresponding survival rates were 92.6%, 87.2%, and 78.2% (P < .05). FFP rates were significantly different between the patients who achieved CR and those who did not achieve CR after CT: 94.6% versus 65.3% (P < .001); corresponding survival rates were 89.9% and 73.7% (P < .01). Multivariate analysis confirmed that MT size and post-CT status were the only two prognostic factors for FFP; for survival, the same two characteristics, as well as age (< 40 v > or = 40 years), significantly affected prognosis. We were thus able to identify three groups. The 33 patients (12.6%) with a BuMT had 10-year FFP and survival rates of 63.0% and 78.2%, respectively. Of 229 patients without BuMT, the 195 who attained CR after CT had an optimal prognosis (FFP, 96.6%; survival, 93.6%), while those who failed to achieve CR after CT had an intermediate prognosis (FFP, 68.8%; survival, 77.6%). CONCLUSION: These results demonstrate the independent impact on HD prognosis of tumor burden and post-CT status.

Adolescent↗
PubMed1995

Inclusion/exclusion of fatty acids in amylose complexes as a function of the fatty acid chain length.

Structural models are proposed for amylose-fatty acid complexes depending on the respective chain lengths of their constituents. The three studied fatty acids induce the Vh amylose crystalline type. However, in contrast to lauric and palmitic acids, caprylic acid is not present in crystals. On the basis of the relative amounts of amylose and fatty acid determined in complexes and previous results of molecular modelling, inclusion of lauric and palmitic acids inside the amylose helices is proposed; the acyl chains are included in crystalline areas and the carboxylic groups in amorphous areas. The absence of caprylic acid in crystals could be due to the solubility of this compound in the crystallization medium.

Amylose↗
PubMed1995

Comparison of Epstein-Barr virus markers in Reed-Sternberg cells in adult Hodgkin's disease tissues from an industrialized and a developing country.

The link between Hodgkin's disease (HD) and Epstein-Barr virus (EBV) is well documented in childhood and here the same hypothesis has been examined in adults, by comparing cases from an industrialized and a developing country. In this study the prevalence of EBV markers in nodal lesions of adult HD were compared in 21 patients from France (Fr) and 25 from Algeria (Al), all clinically staged during 1990-1992. Median age was 29 years. Histologic subtypes included lymphocytic predominance (LP) Fr 1; nodular sclerosis (NS) Fr 16, Al 16; mixed cellularity (MC) Fr 4, Al 9. EBV markers examined included expression of latent membrane protein (LMP) in Reed-Sternberg and Hodgkin cells (RSC) by immunochemistry; EBV-DNA and -RNA in situ hybridization (ISH); EBV-DNA by polymerase chain reaction (PCR). Results showed that RSC were LMP-positive in 4 (2 NS, 2 MC) French and 7 (3 NS, 4 MC) Algerian. All LMP+ cases were also positive for EBV DNA-RNA ISH. ISH was positive in RSC of 33% of the French and 72% of Algerian patients (p < 0.02). The positivity was more frequent in MC (77%) than in other histologic types (45%). The EBV genome was detected by PCR on DNA extracted from frozen samples in 84% of Fr and 95% of Al patients (100% of MC and 86% of other histologic types). Conclusion. The discrepancy between PCR and ISH results may be due to the lesser sensitivity of the ISH technique, or, alternatively, to the presence of EBV in the lymphoid cells surrounding RSC.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Human immunodeficiency virus associated Hodgkin's disease: report of 45 cases from the French Registry of HIV-Associated Tumors.

Clinical and pathological characteristics as well as outcome of 45 Hodgkin's disease (HD) cases collected by the French registry of HIV-associated tumors between January 1987 and December 1989 (all clinically staged according to the Ann Arbor system) were analyzed and compared with those of a cohort of 407 patients with clinical stages (CS) IA to IVB enrolled between September 1981 and August 1988 in a multicentric clinical trial. The route of HIV infection, initial CD4 cell count at the time of HD diagnosis and CDC class of HIV infection were studied as well as the progression to AIDS onset were recorded. HIV-HD is characterized by a predominance of advanced CS (75%), B symptoms (80%) and mixed cellularity histology (49%), as well as by early bone marrow involvement (24%); a specific feature is the rare occurrence of mediastinal involvement (13% in HIV-HD versus 71% in primary HD). With standard therapies, 79% of the patients achieved a complete remission, but hematological and infectious complications were very frequent. The proportion of intravenous drug abusers (IVDA) in HIV-HD (38%) is higher than in French HIV-infected population as a whole (20.8%). Median CD4 cell count was 306/microliters at the time of HD diagnosis, while only 5 cases (11%) were preceded by an AIDS manifestation; progression to AIDS rate was 94% at 2 years. Overall 2-year survival was 41%, with 71% for patients with an initial CD4 cell count over 300/microliters and 0% for those with CD4 cell count lower than 300/microliters (p < 0.01); opportunistic infections were the most frequent cause of death. HIV-HD seems to occur preferentially in.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1995

[Association of Epstein-Barr virus and Hodgkin's disease: comparison between Algerian and French patients].

The prevalence of Epstein-Barr virus (EBV) markers in nodal lesions from Algerian (Al) patients (n = 47) was compared to French (Fr) patients (n = 21) with Hodgkin's disease. Initial characteristics were: males Fr 57%, Al 53%; median age Fr 29, Al 26; histologic subtypes: lymphocytic predominance (LP) Fr 1, Al 2; nodular sclerosis (NS) Fr 16, Al 19; mixed cellularity (MC) Fr 4, Al 12; lymphocytic depletion (LD) Al 2. The latent membrane protein (LMP) was expressed in Reed-Sternberg cells (RSC) in 16 Al (4 NS, 12 MC) and 4 Fr (2 NS, 2 MC) cases. All LMP-positive cases were also positive by DNA or RNA in situ hybridization (ISH). ISH was positive in RSC of 29% of Fr and 66% of Al patients (p < 0.02); the positivity was more frequent in MC (80%) than in other histologic types (39%). EBV genome was detected by PCR on DNA extracted from frozen samples in 84% of Fr and 95% of Al patients (100% of MC and 86% of other histologic types). The discrepancy between PCR and ISH results can be due to a lesser sensitivity of the latter technique, or, alternatively, to the presence of EBV in lymphoid cells surrounding RSC. ISH positivity was more frequent in young Al adults than in Fr ones. This more pronounced HD-EBV link in patients from a developing country compared with an industrialized one can result from the age at primary EBV infection, which occurs earlier in Algeria than in France.

Adolescent↗
PubMed1995

Digestion of raw banana starch in the small intestine of healthy humans: structural features of resistant starch.

The digestion of freeze-dried green banana flour in the upper gut was studied by an intubation technique in six healthy subjects over a 14 h period. Of alpha-glucans ingested, 83.7% reached the terminal ileum but were almost totally fermented in the colon. Structural study of the resistant fraction showed that a small part of the alpha-glucans which escaped digestion in the small intestine was composed of oligosaccharides from starch hydrolysis, whereas the rest was insoluble starch in granule form with physical characteristics similar to those of raw banana starch. Passage through the small intestine altered granule structure by increasing susceptibility to further alpha-amylase hydrolysis. Compared with resistant starch values in vivo, those obtained with the in vitro methods tested were inadequate to estimate the whole fraction of starch reaching the terminal ileum.

Adult↗
PubMed1994

Comparative study of the acute effects of resistant starch and dietary fibers on metabolic indexes in men.

The effect of ingestion of the same amount (30 g) of a resistant starch (lintner) and cellulose on energy expenditure (EE), colonic fermentation (breath-hydrogen test), and blood glucose, insulin, and free fatty acid (FFA) concentrations were compared in seven healthy volunteers in a first experiment. In a second experiment the same indexes were measured in six healthy volunteers after the ingestion of diets composed of 50 g glucose alone or mixed with 30 g lintner, or cellulose, or pectin. In the first experiment no differences between lintner and cellulose were observed on the measured indexes. The notable difference was the increased apparent colonic fermentation with lintner after 6 h. In experiment 2, although insulin response was significantly lower in the pectin-added diet, the results obtained with the four different diets were not significantly different. The metabolic characteristics of lintner were closer to cellulose than to pectin. In conclusion, the acute effect of the ingestion of a resistant starch (lintner) on the measured metabolic indexes is similar to that of a known insoluble fiber--cellulose.

Adult↗
PubMed1994

[Assessment of viable myocardium after infarction with transesophageal echocardiography and myocardial echocontrastography].

Left ventricular recovery of dysfunctioning but viable myocardium can occur only in tissue in which both myocardial contractile reserve and microvascular integrity are preserved. Recent studies have demonstrated that both inotropic stimulating echo tests and myocardial contrast echocardiography can be used to assess myocardial viability in post-myocardial infarction patients. Therefore we performed a transesophageal and myocardial contrast echocardiographic evaluation of post-myocardial infarction patients to assess: the respective accuracy of post-extrasystolic potentiation and low-dose dobutamine (5 and 10 mcg) during transesophageal echocardiography in eliciting contractile reserve, and the potential of myocardial contrast echocardiography in predicting later functional recovery. Results of our studies showed comparable effects of low-dose dobutamine (5 mcg) and post-extrasystolic potentiation in increasing myocardial thickening while low-dose dobutamine (10 mcg) had a greater potential in eliciting residual contractility. Lastly, myocardial contrast echocardiography provided a clear spectrum of intramyocardial perfusion patterns in dysfunctioning areas but did not accurately correlate with later functional recovery as better predicted by low-dose dobutamine in the same segments. In conclusion, these methods represent the preferred choice of studying the perfusion-contraction match in viable myocardium thus playing an important role in prognostic and therapeutic strategies in myocardial infarction patients.

Echocardiography↗
PubMed1994

Detection of the expression of the Epstein-Barr virus latent gene product in Hodgkin's lymph nodes by immunostaining. Comparison between paraffin sections and imprints.

The latent membrane protein (LMP) of Epstein-Barr virus can be detected by an immunostaining method in about 50% of Hodgkin's disease lymph node tumour cells on frozen sections. The same method had been successfully employed on paraffin-embedded (PE) sections. We used this immunostaining method on imprints (IP) and PE sections of 26 Hodgkin's lymph nodes. Overall, there were 11 LMP-positive cases; immunostaining was stronger in IP than in PE samples; in nine cases both IP and PE samples were LMP-positive; in two, imprints were LMP-positive when PE sections were LMP-negative.

Adolescent↗
PubMed1993

Morphological and structural features of amylose spherocrystals of A-type.

Amylose spherocrystals of A-type were grown by mixing ethanol with hot aqueous solutions of short chain amylose followed by slow cooling to 4 degrees C. The spherocrystals which had a diameter of the order of 10 microns were observed by scanning electron microscopy and analysed by X-ray diffraction. They were also cross-sectional for transmission electron microscopy and electron diffraction investigation. These techniques showed that each spherocrystal consisted of an assembly of thin elongated single crystal-like domains of A-type amylose radiating from the centre of the spherocrystal. In each of these domains, the chain axis of amylose was found to be aligned with the long axis of the domain, in agreement with the overall positive optical birefringence observed for the spherocrystals. The spherocrystals which were rather fragile broke easily along the boundaries of the crystalline domains. This could explain the susceptibility of these structures to alpha-amylase digestion.

Amylose↗