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Biomedical subjects

P Besson

Publications and source records attributed to P Besson.

At least 19 recordsLinked to original sources
PubMed2003

[Value of MRI in symptomatic patients treated with tamoxifen].

PURPOSE: To assess the MR imaging (MRI) findings in symptomatic tamoxifen treated-women with abnormal transvaginal sonography. PATIENTS AND METHODS: From january 1997 to june 2000, 32 consecutive symptomatic tamoxifen treated-women with abnormal transvaginal sonography were prospectively studied by MRI. T1-weighted, T2-weighted, post-contrast T1-weighted and dynamic gradient-echo T1-weighted sequences were used. All patients underwent uterine sampling within one month of MRI. RESULTS: Endometrial thickness at sonography ranged from 5 to 48 mm (mean thickness 19 mm), and on T2-weighted imaging ranged from 3 to 50 mm (mean=25 mm). Three MRI patterns were found. Pattern 1 (13 patients) was defined as homogeneous high signal intensity of the endometrium on T2W images, and signal void in the lumen on gadolinium-enhanced images. Pattern 2 (8 patients) was defined as heterogeneous endometrial signal on T2W images, and latticelike enhancement traversing the endometrial canal on gadolinium-enhanced images. Pattern 3 (11 patients) was defined as heterogeneous signal on T2W images with masses or nodules which were better seen on dynamic gadolinium-enhanced images. In pattern 1 we found 13 atrophic endometrium, in addition there were 4 polypoid glandulo-cystic proliferation (PGCP), and 1 adenomyosis. In pattern 2 we found 3 PGCP, 4 atrophy and 1 polyp without hyperplasia. The 2 carcinomas and the polyps with hyperplasia were found in pattern 3 (11 patients). CONCLUSION: In our experience MRI allows differentiation of lesions which may require surgery from other lesions in which noninvasive follow-up is possible.

Aged↗
PubMed2000

[Predictive value of preoperative abdominopelvic CT for optimal cytoreduction surgery in ovarian carcinoma].

Some patients underwent laparoscopy without optimal debulking surgery as initial treatment for advanced ovarian carcinoma. The amount of residual tumor following primary surgery was an important prognosis factor. Neoadjuvant chemotherapy is a new therapeutic approach. Secondary, optimal surgery could be done in better conditions. The purpose was to access the ability of preoperative abdominopelvic CT to predict success of debulking surgery for ovarian carcinoma: less than 1 cm of residual tumor size after initial surgery. We reviewed 39 patients (2 stages Ic, 1 stage IIc, 22 stages III and 14 stages IV) operated on for ovarian carcinoma between January 1992 and December 1997. Surgical criteria of inability to perform optimal surgical cytoreduction were compared with abdominopelvic CT done the month before. CT scans were prospectively assessed by radiologist A and retrospectively (3 months to 6 years delay) rewiewed separately by radiologists A and B without surgical data. Nineteen patients underwent optimal debulking surgery: 13 no residual tumor and 6 with residual lesions under 1 cm. The interreader (0.73) and intrareader (0.9) agreement, worked out by Kappa coefficient, was juged good to very good. The sensitivity of CT was 91% with a specificity of 95%. These results allowed us to determine wich CT criteria were accurate and reproducible to be a helpfull for therapeutic choice and to avoid laparotomy without optimal surgery.

Aged↗
PubMed2000

[Predictive value of abdominopelvic scan for optimal surgery of ovarian carcinoma].

BACKGROUND: Some patients undergo laparoscopy without optimal debulking surgery as initial treatment for advanced ovarian carcinoma. The amount of residual tumor following primary surgery is an important prognosis factor. Neoadjuvant chemotherapy is a new therapeutic approach. Secondary, optimal surgery could be done in better conditions. PURPOSE: To access the ability of preoperative abdominopelvic CT to predict success of debulking surgery for ovarian carcinoma: less than 1cm of residual tumor size after initial surgery. MATERIALS AND METHODS: We reviewed 39 patients (two stage Ic, 1 stage IIc, 22 stage III and 14 stage IV) operated on for ovarian carcinoma between January 1992 and December 1997. Surgical criteria of inability to perform optimal surgical cytoreduction were compared with abdominopelvic CT done the month before. CT scans were prospectively assessed by radiologist A and retrospectively (3 months to 6 years delay) reviewed separately by radiologists A and B without surgical data. RESULTS: Nineteen patients underwent optimal debulking surgery: 13 no residual tumor and 6 with residual lesions under 1cm. The interreader (0.73) and intrareader (0.9) agreement, worked out by Kappa coefficient, was judged good to very good. The sensitivity of CT was 91% with a specificity of 95%. CONCLUSION: These results allowed us to determine which CT criteria were accurate and reproducible to be a helpful for therapeutic choice and to avoid laparotomy without optimal surgery.

Adenocarcinoma↗
PubMed1999

[Computed tomography-guided transthoracic biopsy after negative fiber-optic endoscopy; apropos of 134 patients].

PURPOSE: To evaluate the diagnostic accuracy of transthoracic needle biopsy (TNB) in patients being treated for cancer in order to compare results from small and large pulmonary nodules and to study the efficiency of pathology versus cytology analysis. PATIENTS AND METHODS: 141 consecutive CT-guided TNBs were performed in 134 patients. Cancer had been diagnosed in all cases. From the CT images, nodules were classified as small (< or = 15 mm) (n = 63; 47%) or large (> 15 mm) (n = 71; 53%). RESULTS: There were 16 benign and 118 malignant lesions (92 metastasis, 18 primary, 8 unspecified). There was no statistically significant difference for sensitivity and for prevalence of pneumothorax between small or large nodules. For the 107 true-positive and 16 true-negative results, the cytology examination was positive alone in 41 cases (33.3%), the pathology examination in 24 cases (19.5%) and both in 58 cases (47.2%). CONCLUSION: The diagnostic efficiency of CT-guided transthoracic needle biopsy is as good for small pulmonary nodules (> or = 15 mm) as for larger lesions. This technique is particularly useful in the diagnosis of secondary lesions and does not increase the risk of complications, even in case of small nodules. Ordering both pathology and cytology examinations improves the efficacy of TNB.

Adolescent↗
PubMed1999

Multi-parameter observation of environmental asbestos pollution at the Institut de Physique du Globe de Paris (Jussieu Campus, France).

An original multi-parameter system has been used to study the nature of dust in the ambient air, particularly the total fibers and asbestos fibers, in eight areas of the Institut de Physique de Globe de Paris (France). These analyses provide a detailed case study of environmental pollution by asbestos fibers at low levels. The levels of total fibers with a length greater than 3 microns, measured with a real time fiber analyser monitor (FAM), give a baseline of 2.5 fibers per l., throughout the duration of sampling. The same levels, calculated during periods of effective presence of staff, are smaller than 10 fb per l. During these periods, the instantaneous value can show high peaks, reaching a maximum of 60 fb per l., but more often of about 5 to 10 fb per l. A direct cause and effect relationship exists between fiber concentrations and the presence of people, and indirectly with the variation of the other environmental parameters (temperature, humidity, air velocity). The baseline concentration of asbestos fibers, determined by analytical transmission electron microscopy (ATEM), is about 10(-1) fb per l., with a mean value during the presence of people always less than 1.5 fb per l. The low levels of asbestos fibers do not allow us to establish a precise correlation between the concentration of total fibers and the asbestos concentration, but a rough estimate suggests that asbestos could represent 10-20% of the airborne fibers monitored with the FAM. The statistical study of fiber sizes shows that 70 and 55% of analyzed chrysotile and amosite fibers respectively are smaller than 5 microns. These numbers are 40 and 35% for fibers smaller than 3 microns, which are undetected by the FAM. Amosite, which characterizes most of the asbestos-containing materials (ACM) in the analyzed areas, is detected in the ambient air in quantities ten times less important than chrysotile. The low asbestos levels and the difference between the nature of building asbestos and airborne fibers, show that the mean measured asbestos contents in the ambient air represent the geochemical background of chrysotile asbestos fibers in the Parisian air.

Air Pollution↗
PubMed1998

Long-term supplementation of culture medium with essential fatty acids alters alpha-linolenic acid uptake in Caco-2 clone TC7.

We investigated the influence of four different culture media: 20% fetal bovine serum (FBS), 5% FBS, 5% FBS supplemented with 10 mg x L(-1) linoleic acid (18:2(n-6)) or alpha-linolenic acid (18:3(n-3)) on alpha-linolenic acid apical uptake in clone TC7 of human intestinal Caco-2 cell line. Neither cellular viability nor cell monolayer integrity and permeability were altered by the four culture conditions. Our results show that the different culture media led to changes in alpha-linolenic acid maximal rate of uptake (Vmax) but did not alter the apparent transport constant (Km). Reducing FBS concentration from 20% to 5% increased significantly the rate of alpha-linolenic acid uptake, which was further increased by supplementation of the medium with 18:2(n-6) or 18:3(n-3). Supplementation with essential fatty acids led to a marked enrichment of brush-border membrane phospholipids in polyunsaturated fatty acids of the corresponding series and decreased significantly the levels of monounsaturated fatty acids. Saturated fatty acids, unsaturation index, and cholesterol/fatty acid ratios were unchanged. No clear relation could be established between the changes in membrane lipid composition and the alterations of alpha-linolenic acid uptake. These results indicate a weak influence of membrane lipid composition in the modulation of the uptake. Therefore, the increase of uptake following long-term supplementation of TC7 cells with essential fatty acids could be attributed to an increase of the expression of membrane protein(s) involved in the apical uptake of long-chain fatty acids. This remains to be established.

Animals↗
PubMed1998

Regulation of Na+/H+ exchanger gene expression: mitogenic stimulation increases NHE1 promoter activity.

We examined factors important in regulation of expression of the Na+/H+ exchanger gene in NIH/3T3 cells. A stable fibroblast cell line was generated that contained a 1.1-kb proximal fragment of the mouse NHE1 promoter. The addition of serum to serum-starved cells resulted in an increase in activity of the NHE1 promoter. The mitogenic agonists insulin, thrombin, and epidermal growth factor also increased transcription from the NHE1 promoter. Phorbol esters also increased NHE1 promoter-directed transcription, whereas the serine/threonine protein kinase inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine inhibited this stimulation. The protein kinase inhibitors GF-109203X, PD-98059, and genistein all stimulated promoter activity. Promoter deletion analysis and gel mobility shift assays showed that a region between 0.9 and 1.1 kb from the start site was involved in mediating the effect of mitogenic stimulation. The results show that a variety of mitogenic factors can activate the NHE1 promoter during cell growth and proliferation.

3T3 Cells↗
PubMed1998

[Comparative study of tumor evaluation with computerized tomography and surgery in ovarian cancer].

PURPOSE: To evaluate the results of an abdomino-pelvic scan in cancers of the ovary in comparison with surgery. MATERIAL AND METHODS: We reviewed the observations concerning patients operated on for malignant tumors of the ovary between January 1992 and April 1995 in our anti-cancer center. We selected 32 patients who had had both a complete surgical abdominal exploration (laparotomy or laparoscopy) and an abdominal pelvic scan in the preceding months. We divided the abdomen into 33 areas and compared the scan of each with the surgical findings. Two cancer radiologists, including one gynecology specialist, studied the imaging separately. Neither knew the results of the surgical observations. RESULTS: Imaging findings varied with localization tumor size and presence or not of ascites radiologists. For certain localization, detection of lesions was difficult for both readers (pancreas, spleen, stomach), for others, recognition improved with experience (bowel, diaphragm, colon). CONCLUSION: The clinician must be aware of the variability of ovarian cancer assessment by CT scan, particularly if imaging alone is being used to guide treatment.

Abdominal Neoplasms↗
PubMed1997

Mechanisms and kinetics of alpha-linolenic acid uptake in Caco-2 clone TC7.

The uptake kinetics of alpha-linolenic acid (18:3(n - 3)), an essential fatty acid, were investigated in the human intestinal cell line Caco-2. Four clones (PD10, PF11, PD7 and TC7) from the heterogeneous parental Caco-2 cells population were used. After a screening step using isolated cells, the TC7 clone was selected for the study of alpha-linolenic acid uptake. [1-(14)C]linolenic acid dissolved in 10 mM taurocholate was presented to the microvillus plasma membrane (apical side) of TC7 differentiated cells, grown on a semi-permeable polycarbonate membrane. The results show that the initial rate of uptake is not a linear function of the 18:3(n- 3) monomer concentration in the incubation medium. In the monomer concentration range studied (0.2 to 36 microM) apical uptake was saturable and followed Michaelis-Menten kinetics (V(max) = 15.4 +/- 0.6 nmol/mg protein per min, K(m) = 14.3 +/- 1.3 microM). In addition, it was temperature- and energy-dependent but was apparently unaffected by the sodium gradient and intracellular metabolic fate of 18:3(n - 3). Excess of unlabeled saturated or unsaturated long chain fatty acids (C16 to C22) led to a 27-68% reduction of [1-(14)C]linolenic acid uptake. Likewise basolateral uptake was saturable (V(max) = 4.9 +/- 0.7 nmol/mg protein per min, K(m) = 8.7 +/- 2.9 microM). These facts argue in favour of the existence in these human intestinal cells of a carrier-mediated transport system for alpha-linolenic acid and probably other long chain fatty acids as well.

Adenocarcinoma↗
PubMed1997

Supplementation of MCF-7 cells with essential fatty acids induces the activation of protein kinase C in response to IGF-1.

The effects of changing the composition of membrane lipids on protein kinase C (PKC) activation were studied in MCF-7 human breast cancer cells. The supply of linoleate or alpha-linolenate to MCF-7 cells altered cell membranes fatty acid composition but did not affect PKC activity. When the cells were additionally exposed to IGF-1, the same fatty acids caused a dramatic increase in membrane-bound PKC activity. We also found that the mitogenic response induced by IGF-1 was not enhanced in those conditions when PKC becomes activated by linoleate and alpha-linolenate. These data show that these fatty acids elicit a distinct route for the transmission of IGF-1 signal by inducing the PKC pathway. They suggest that linoleate and alpha-linolenate could control the biological response of MCF-7 cells to IGF-1.

Breast Neoplasms↗
PubMed1996

Inhibition of Na+/H+ exchanger activity by an alkyl-lysophospholipid analogue in a human breast cancer cell line.

The mechanisms by which ET-18-OCH3 (1-O-octadecyl-2-O-methyl-sn-glycero-3 -phosphocholine) and other analogues of alkyl-lysophospholipids exert their antineoplastic effects are not yet fully elucidated. Possible interference with mechanisms involving intracellular pH (pHi) regulation was examined by measuring the effect of ET-18-OCH3 on the activity of the Na+/H+ exchanger in the breast cancer-derived cell line MCF-7. When ET-18-OCH3 was added to culture medium at 10 muM (determined as a noncytotoxic but cytostatic concentration), it led to an intracellular acidification (0.15 pH unit). It also decreased the rate of pHi recovery by Na+/H+ exchange following artificial acidification. Kinetic parameters of the exchange indicated that this was due to a decrease in the affinity of the exchanger for both transported ions, rather than to a decrease in the number of exchanger proteins in the membrane (same maximal efflux rate for treated and untreated cells). These results suggest that Na+/H+ exchanger inhibition and subsequent cytoplasmic acidification participate in the mode of action of ET-18-OCH3, and could be used for modulation of tumor-cell chemosensitivity or their subsequent commitment into programmed cell death.

Antineoplastic Agents↗
PubMed1994

Na(+)-H+ antiporter activity in relation to membrane fatty acid composition and cell proliferation.

Na(+)-H+ exchange activity was studied in a human breast cancer cell line. At steady state, the intracellular pH (pHi) of the cells was 7.23 +/- 0.01, and intracellular buffering capacity (beta i) was 44 +/- 4 mM/pH unit. pHi was controlled by a Na(+)-H+ antiporter that was reversible, electroneutral, inhibited by 5-(N-methyl-N-isobutyl)amiloride, and dependent on extracellular Na+. The exchanger function depended on internal H+ concentration, according to an allosteric activation mechanism obeying the model of Hill. The exchanger was inactive at pHi > or = 7.22, and its maximal activity was reached at pHi < 6.60. The exchanger was stimulated by osmotic shrinking but was unaffected by growth factors (epidermal growth factor, insulin-like growth factor I) or by serum. When cells were grown in a medium supplemented with linoleic or alpha-linolenic acids, large quantities of the additional fatty acid accumulated in membranes, saturated fatty acids increased, and monounsaturated fatty acids decreased. These changes reduced cell proliferation but had no effect on the steady-state value of pHi, on beta i, or on the kinetic parameters of the Na(+)-H+ exchanger. Therefore, in this system, cell proliferation is not directly related to the activation of the Na(+)-H+ exchanger.

Acids↗
PubMed1989

Presence of PAF-acether in human breast carcinoma: relation to axillary lymph node metastasis.

PAF-acether (PAF; formerly platelet-activating factor), a potent lipid mediator of inflammation, is involved in multiple cellular functions. To evaluate the role of PAF in human cancer, we obtained specimens from patients with localized breast carcinoma and assayed them for PAF. PAF was found in almost all carcinoma, although it was not detected in most of the matched, nontumor breast tissue samples. Intratumor PAF level was elevated when axillary lymph node involvement was low. Greater axillary extension (two or more positive lymph nodes) was associated with a decreased intratumor PAF level. These findings, along with the independence of other prognostic factors, indicate that PAF is a tumor marker of axillary lymph node involvement.

Axilla↗
PubMed1989

[Clinically localized cancers of the breast. Therapeutic consequences of the evaluation of extension].

The therapeutic modifications induced by pretreatment evaluation were studied in a consecutive series of 852 asymptomatic women with newly diagnosed primary breast cancer attending our center between 1980 and 1984. Staging tests included chest X-rays in 851 patients, bone X-rays in 831, alkaline phosphatase in 826, hepatic enzymes in 818, liver echography in 750 and bone scintigraphy in 504. The intended local treatment was changed for a systemic one in 8 patients due to suspicious abnormalities. The follow-up confirmed evidence of metastases in 6 out of 8 patients (bone: 4; liver: 1; lung: 1). Mastectomy, initially avoided in these 6 patients, was subsequently performed in 2 of them owing to slow progression of distant metastases. On the basis of the current study, pretreatment staging in asymptomatic primary breast cancer cannot be recommended due to the low prevalence of detectable metastases.

Adult↗
PubMed1989

[Transvaginal echography in gynecologic oncology].

Conventional transabdominal sonography is being challenged by the use of a transvaginal probe, because this technique reveals details and images of the female reproductive tract not previously visualized. Our experience of about 3,000 patients, the including 700 patients with gynecologic cancer, indicates that the TV approach will replace conventional transabdominal sonography as the initial study for female pelvic lesions.

Female↗