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Biomedical subjects

C Chassagne

Publications and source records attributed to C Chassagne.

At least 19 recordsLinked to original sources
PubMed2005

Electrically induced anisotropy in a colloidal dispersion of nanospheres as measured by electric birefringence.

Electrically induced birefringence experiments were performed on dispersions consisting of sulfate latex nanospheres of two different sizes and charges dispersed in an electrolyte solution, at various ionic strengths. The induced birefringence was found to have an important contribution increasing as a quadratic power law of the volume fraction of the spheres. This shows that interparticle interactions play a role in the observed birefringence. The data were analyzed, using a theory from Hafkenscheid and Vlieger [Physica 75 (1974) 57], in terms of the changes of the interparticle separations in the directions parallel and perpendicular to the applied electric field.

Journal Article↗
PubMed2004

Primary cardiac Burkitt lymphoma in a child.

Primary cardiac lymphoma (PCL) is a rare and usually fatal malignancy, seldom reported in children. This report describes the case of a 10-year-old boy who presented with multiple intracardiac masses which, when biopsied, proved to be small non-cleaved cell (Burkitt's) lymphoma. The first two cycles of chemotherapy according to the LMB 96 protocol were given under close cardiological supervision, with good response. The treatment was then continued with full-dose chemotherapy, without any cardiological complication. The patient who was treated by chemotherapy alone remains in complete remission 36 months after the end of treatment and can presently be considered as cured, without late cardiac effect.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2002

The interpretation of dielectric spectroscopy measurements on silica and hematite sols.

Experimental data on the dielectric response of silica and hematite sols from the literature are interpreted using an analytical theory developed previously (Chassagne, C., Bedeaux, D., and Koper, G. J. M., J. Phys. Chem B105, 11,743 (2001), and Physica A, to be published). The theory is found to correctly predict both the relaxation frequency and the dielectric permittivity enhancement at low frequencies with only one free parameter. This parameter can be the zeta potential or the Stern layer conductance, in the case that the zeta potential is fixed to agree with the electrophoretic mobility measurements.

Journal Article↗
PubMed2002

A multicenter study of treatment of primary CNS lymphoma.

OBJECTIVE: To characterize the therapeutic variables correlated to outcome in 370 patients with primary CNS lymphoma. METHODS: Planned treatment was radiotherapy (RT) in 98 patients, chemotherapy (CHT) in 32, RT followed by CHT in 36, and CHT followed by RT in 197 patients. High-dose methotrexate (HD-MTX; 1 to 8 g/m2) was used in 169 patients and intrathecal CHT in 109. RESULTS: One hundred sixteen patients are alive (median follow-up 24 months), with a 2-year overall survival of 37%. Patients treated with CHT followed by RT had improved survival with respect to patients treated with RT alone. Patients receiving HD-MTX-based primary CHT survived longer than those treated with other drugs. HD-MTX associated with other cytostatics, in particular HD-cytarabine, produced better results than HD-MTX alone. No correlation between MTX dose and survival was found. In patients receiving HD-MTX, consolidation RT or intrathecal CHT did not improve survival. Age, performance status, lactate dehydrogenase serum level, CSF protein level, site of disease, and use of HD-MTX were all predictors of survival. CONCLUSIONS: Combination CHT-RT is superior to RT alone. Patients treated with primary CHT containing HD-MTX exhibited improved survival. In these patients, the addition of HD-cytarabine was associated with a better survival, whereas intrathecal CHT was not correlated to outcome. RT may be unnecessary in patients achieving complete remission after receiving HD-MTX-based primary CHT.

Adolescent↗
PubMed2002

Relevance of intraocular involvement in the management of primary central nervous system lymphomas.

BACKGROUND: Reported data regarding intraocular lymphoma (IOL) management are anecdotal. Cases of IOL included in an international multicentre series of 378 immunocompetent patients with primary central nervous system lymphomas (PCNSLs) were reviewed. PATIENTS AND METHODS: Staging included slit-lamp examination in 170 patients: IOL was diagnosed in 22 cases (13%). A concomitant brain lesion was detected in 21 cases. Planned treatment was chemotherapy followed by radiotherapy in 13 cases, chemotherapy alone in three and radiotherapy, followed by or not by chemotherapy in five; one patient was not treated. Chemotherapy included high-dose methotrexate in 12 cases. Ten patients received intrathecal chemotherapy. Radiotherapy consisted of whole brain irradiation, followed by or not by a tumour bed boost; ocular irradiation was planned in 15 cases. Irradiation in one patient without brain lesions was limited to the orbits only (50 Gy). RESULTS: IOL was positively correlated to systemic symptoms and meningeal disease. Fifteen patients (71%) achieved an objective response; 16 patients experienced a failure (2-year failure-free survival 34+/-10%). Failures involved the eyes in eight cases, with a 2-year time to ocular relapse of 59+/-11%. Ocular failure was less common in patients treated with chemotherapy plus ocular irradiation and was associated with a significantly shorter survival. Seven patients are alive [median follow-up 53 months, 2-year overall survival (OS): 39+/-11%] , five of whom were treated with ocular irradiation. The patient with isolated IOL is alive and disease-free at 14 months. OS of the entire series was similar to that of PCNSL patients with negative slit-lamp examination. CONCLUSIONS: IOL is usually associated with concomitant brain disease and shows a survival similar to that of the rest of PCNSLs. Chemotherapy combined with ocular irradiation resulted in better control of ocular disease, which seems to be associated with survival. In view of the potential role of ocular irradiation, the use of chemotherapy alone in phase II trials should be critically reconsidered in PCNSL patients with ocular disease.

Adolescent↗
PubMed2001

Non-Hodgkin's lymphoma of the testis: a retrospective study of 84 patients treated in the French anticancer centres.

Primary non-Hodgkin's lymphoma of the testicle is rare. We analysed cases treated in French anticancer centres from 1969 to 1995. All cases were reviewed and classified according to the R.E.A.L. Classification. Eighty-four cases were included in this study. The median age was 67 years (17-85). Disease was classified as stages I in 42 cases, stages II in 19 and stages III-IV in 23. Diffuse large B-cell lymphoma was diagnosed in 75% of cases. Treatment included orchidectomy and radiotherapy and/or chemotherapy. A complete response was obtained in 72.6% of the patient population and in 100%, 68% and 33% of stage I, II and III-IV disease respectively. Recurrence occurred in 32 cases and the most frequent site was the central nervous system: six of these patients presented stage I disease. Median overall survival was 32 months for the entire population, 52 months for stage I, 32 months for stage II, and 12 months for stage III-IV cases (P < 0.0001). Among patients presenting stage I disease, no difference was found between those treated with combined surgery and chemotherapy or surgery followed or not followed by radiotherapy. This study confirms that non-Hodgkin's lymphoma of the testicle carries a poor prognosis. Systemic adjuvant chemotherapy should be discussed because of the high recurrence rate. Inclusion of these cases in large co-operative prospective studies is recommended.

Adolescent↗
PubMed2000

Effect of pressure overload on angiotensin receptor expression in the rat heart during early postnatal life.

The development of cardiac hypertrophy during neonatal life and in adults implies different processes. The angiotensin II (Ang II) system is involved in the development of cardiac hypertrophy in adults, but its role in neonates remains unclear. The aim of this study was to estimate the influence of increased hemodynamic load on the developmental pattern of the AT1/AT2 receptor expression in the heart. Two-day-old rats submitted to abdominal aortic constriction (AC) or sham operation were sacrificed 2 h, and 1, 3, and 8 days after surgery. Ang II was evaluated in sera and immunohistology was performed to define the cardiac hypertrophy process. The Ang II receptor subtypes 1 and 2 were quantified at the receptor and mRNA levels by(125)I-Ang II binding and RT-PCR, respectively. Ang II content in sera increased transiently 2 h after surgery in the AC group. In sham-operated, AT1 and AT2 decreased throughout the period studied at both mRNA and receptor levels. However, the AT1 mRNA level decrease was more pronounced than that of AT2 (by 57% and 27%, respectively). AC not only prevented the postnatal decrease in AT mRNA level but resulted in an increase in AT1 mRNA 8 days after surgery (P<0.05). Besides in the AC groups, AT2 mRNA levels but not those of AT1 mRNA were linearly correlated with the left ventricular mass. At the receptor level, a significant transient (1 day after surgery) increase in both AT1 and AT2 was observed. In conclusion, our data demonstrated that imposition of pressure overload soon after birth altered the pattern of AT receptor expression.

Animals↗
PubMed2000

Lymphatic mapping and sentinel node biopsy of operable breast cancer.

The aim of this study was to evaluate the reliability and accuracy of sentinel node biopsy for invasive breast cancer and the predictability of axillary node status. Between January 1996 and June 1997 a total of 73 patients underwent patent blue dye lymphatic mapping and sentinel node biopsy followed by standard (level I and II) axillary node dissection (one bilateral procedure). The sentinel node was identified in 82.4% (61/74) of the cases and was predictive of axillary status in 96.7% (59/61). The false-negative rate of the procedure was 8.0% (2/25). The sentinel node was involved in 37.7% (23/61) and was the only one invaded in 30.4% (7/23). The sensitivity of the procedure was 92% (CI95% 74-99%) and its specificity 100%. It is currently considered to be an attractive new procedure undergoing evaluation in prospective controlled trials. This study confirmed the reliability and reproducibility of intraoperative lymphatic mapping and sentinel node biopsy. This is the first step toward a new era of minimally invasive axillary surgery for breast cancer.

Adult↗
PubMed2000

Expression of laminin alpha2 chain during normal and pathological growth of myocardium in rat and human.

OBJECTIVES: Fibrosis is a classical feature of cardiac hypertrophy. To date changes within the basal lamina during normal and pathological cardiac growth have been poorly investigated. The goal of the present study was to determine if the expression of the muscle specific subunit of merosin (laminin alpha2 chain) together with that of fibronectin (FN) is modified in the diseased human heart. Laminin alpha2 chain expression was also investigated during physiological and pathological cardiac growth in the rat. METHODS: In ten normal human hearts and ten hearts with idiopathic dilated cardiomyopathy (IDCM), the laminin-alpha2 and FN mRNA levels were quantified by slot-blot using total RNA and the protein distribution was analysed using an immunofluorescence approach. In Wistar rats, laminin alpha2 and FN mRNA expression was analyzed using RNase protection assay (RPA) and slot-blot assays. RESULTS: The amount of laminin alpha2 mRNA did not vary in normal and pathological human hearts whereas it was significantly decreased in renovascular hypertensive rats (-20%) P<0.05 versus normal tissue). The amount of fibronectin mRNA increased in IDMC patients (x2, P<0.05 versus normal tissue), but was unchanged in hypertensive rats. A negative correlation was found between the cardiac laminin-alpha2 level and the age of the patients whatever the cardiac status. During postnatal development in the rat, a similar decrease in cardiac laminin-alpha2 level was observed between 3 and 30 weeks of age. Finally, the immunofluorescent approach failed to detect any alteration in laminin alpha2 distribution within the human myocardium. CONCLUSION: These data indicate that an imbalance between myocyte hypertrophy and the level of laminin-alpha2 might contribute to alterations in sarcolemmal properties, which occur during the development of cardiac hypertrophy and its transition to cardiac failure.

Analysis of Variance↗
PubMed2000

The extracellular matrix and the cytoskeleton in heart hypertrophy and failure.

Cell characteristics and phenotype depend on the nature of the extracellular matrix, the type and organization of integrins and cytoskeleton. The interactions between these components are poorly known at the myocyte level and during cardiac remodeling associated with cardiac hypertrophy and heart failure. We analyze here the nature and organization of extracellular matrix (ECM) proteins, cytoskeleton and integrins and their regulation by growth factors, such as angiotensin II, in normal myocyte growth and in pathological growth (hypertrophy) of the myocardium and heart failure.

Animals↗
PubMed2000

Modulation of angiotensin II receptor expression during development and regression of hypoxic pulmonary hypertension.

Lung vessel muscularization during hypoxic pulmonary hypertension is associated with local renin-angiotensin system activation. The expression of angiotensin II (Ang II) AT1 and AT2 receptors in this setting is not well known and has never been investigated during normoxia recovery. We determined both chronic hypoxia and normoxia recovery patterns of AT1 and AT2 expression and distal muscularization in the same lungs using in situ binding, reverse transcriptase/polymerase chain reaction, and histology. We also used an isolated perfused lung system to evaluate the vasotonic effects of AT1 and AT2 during chronic exposure to hypoxia with and without subsequent normoxia recovery. Hypoxia produced right ventricular hypertrophy of about 100% after 3 wk, which reversed with normoxia recovery. Hypoxia for 2 wk was associated with simultaneous increases (P<0.05) in AT1 and AT2 binding (16-fold and 18-fold, respectively) and in muscularized vessels in alveolar ducts (2. 8-fold) and walls (3.7-fold). An increase in AT2 messenger RNA (mRNA) (P<0.05) was also observed, whereas AT1 mRNA remained unchanged. After 3 wk of hypoxia, muscularization was at its peak, whereas all receptors and transcripts showed decreases (P<0.05 versus hypoxia 2 wk for AT1 mRNA), which became significant after 1 wk of normoxia recovery (P<0.05 versus hypoxia 2 wk). Significant reversal of muscularization (P<0.01) was found only after 3 wk of normoxia recovery in alveolar wall vessels. Finally, the AT1 antagonist losartan completely inhibited the vasopressor effect of Ang II in hypoxic and normoxia-restored lungs, whereas the AT2 agonist CGP42112A had no effect. Our data indicate that in lungs, chronic hypoxia-induced distal muscularization is associated with early and transient increases in AT2 and AT1 receptors probably owing to hypoxia- dependent transcriptional and post-transcriptional regulatory mechanisms, respectively. They also indicate that the vasotonic response to Ang II is mainly due to the AT1 subtype.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1998

[Identification of axillary sentinel node by lymphotropic dye in breast cancer. Feasibility study apropos of 128 cases].

AIM OF THE STUDY: The goal of this study was to evaluate the technical feasibility of sentinel node biopsy in breast cancer and its predictivity of axillary node status. PATIENTS AND METHODS: Between January 1996 and June 1997, 128 patients with invasive breast carcinomas, referred to the Cancer Center of Strasbourg and Lyon (France), underwent lymphatic mapping (Patent Blue dye) and sentinel node biopsy followed by axillary clearance (Berg's level I to II). RESULTS: Sentinel node was identified in 76.5% of cases and was predictive of axillary status in 94.9% of cases. The false negative rate of the procedure was 5.1%. Sentinel lymph node was involved in 43.9% of cases and it was the only one involved in 30.2% of cases. The sensitivity of the procedure was 94% (CI: 95% = [88%-98%]) and its specificity 100%. CONCLUSION: Actually considered as new attractive procedure under ongoing evaluation in prospective controlled trials, this study confirms the feasibility and reproductibility of lymphatic mapping and sentinel node biopsy, first stage before entering a new era of minimally invasive axillary surgery in breast cancer.

Adult↗
PubMed1993

The molecular biology of heart failure.

In the mammalian heart, the development of cardiac hypertrophy is a common feature that normally precedes all forms of heart failure. This adaptive process involves molecular changes in the myocardium, including the altered expression of several genes encoding proteins for contraction and relaxation. The expression of myosin heavy chain (MHC) and sarcomeric alpha-actin messenger ribonucleic acid (mRNA) changes qualitatively during cardiac hypertrophy; however, their accumulations are not coordinated. Skeletal alpha-actin transcripts accumulate throughout the ventricles and earlier than beta-MHC transcripts, which accumulate primarily around large coronary vessels. Skeletal alpha-actin transcripts also "hyperaccumulate" relative to cardiac alpha-actin mRNA, whose expression does not change. Expression of MHC isomRNA shows an inverse relation; as beta-MHC accumulates, alpha-MHC decreases in abundance. From nuclear run-on assays, we present evidence that the accumulation of these gene products is at least under partial transcriptional control with developmental growth, suggesting that those changes that occur with hypertrophy and heart failure may be primarily transcriptionally regulated. The expression of the mRNA for the calcium-adenosine triphosphate (Ca(2+)-ATPase) of the sarcoplasmic reticulum changes quantitatively with cardiac hypertrophy without the reexpression of a different isoform. The relative mRNA and protein concentrations for this protein diminish with both cardiac hypertrophy and heart failure, a change that may partially explain the delayed relaxation rates seen in hypertrophied and failing hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1993

Antithetical accumulation of myosin heavy chain but not alpha-actin mRNA isoforms during early stages of pressure-overload-induced rat cardiac hypertrophy.

Myocardial response to a hemodynamic overload involves changes in the expression of isogenes encoding myosin heavy chain (MHC) and actin: beta-MHC/alpha-MHC and skeletal/cardiac alpha-actin mRNA isoform ratios are increased. It is not known whether these changes are due to increased accumulations of the two neosynthesized transcripts, beta-MHC and skeletal alpha-actin, or whether the mRNA isoforms normally present, alpha-MHC and cardiac alpha-actin, are concomitantly decreased. To answer these questions, using dot-blot hybridizations, primer extension, and exonuclease VII mapping assays, we have analyzed the content of sarcomeric MHC and actin mRNAs in the poly(A+) RNA in left ventricles of 23-24-day-old rats 18 and 24 hours after a pressure overload induced by stenosis of the thoracic aorta. The results showed a 1.9-fold increase in poly(A+) RNA after the stenosis. Skeletal/cardiac alpha-actin mRNA isoforms were already increased fivefold (from 0.19 to 0.99) at 18 hours, and this was exclusively due to a 5.5-fold increase in skeletal alpha-actin mRNA. At 24 hours, this ratio was increased ninefold (from 0.14 to 1.22), and this was due to a 4.3-fold increase in the level of skeletal alpha-actin mRNAs (p < 0.001) and a 1.9-fold decrease of cardiac alpha-actin mRNA (p < 0.001), restoring the same proportion of sarcomeric actin mRNA in sham-operated and operated rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Actins↗
PubMed1993

[Left ventricular hypertrophy: molecular aspects].

The expression of genes changes during left ventricular hypertrophy. These changes are known as mechanogenic transduction. With respect to the two main contractile proteins, myosin and actin, this is due to a differential expression of their respective multigenic families. Changes of isoform are uncoordinated in time and space. It is important to recognise that the genes themselves are normal and that it is their regulation which is disturbed. Recent data shows that, under normal conditions, the regulation occurs at the transcription stage. A fuller understanding of these mechanisms is necessary if we are to comprehend the pathogenesis of cardiac hypertrophy and failure.

Actins↗
PubMed1992

[Molecular bases of cardiac aging].

The total volume occupied by myocytes in the heart decreases with age, and this is accompanied by a loss of myocytes, by hypertrophy and, to a lesser extent, by hyperplasia of the remaining myocytes. There are differences between ventricles: the right ventricular myocytes have a greater capacity for replication than those of the left ventricle. The expression of genes coding for the 2 principal contractile proteins (myosin and actin) is modified, and there are strong resemblances between the phenotype of the aged heart and that of an adult heart with haemodynamic overload.

Actins↗