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Biomedical subjects

J Boyer

Publications and source records attributed to J Boyer.

At least 127 records · Page 7Linked to original sources
PubMed1993

[Place of endorectal ultrasonography in the evaluation of staging of cancer of the rectum: before or after preoperative radiotherapy?].

Of 62 patients with rectal carcinoma, who were examined by endorectal ultrasound (EER) before operation, 15 were examined after preoperative external radiation therapy. The results were compared to histological and surgical findings according to the TNM classification. When preoperative radiation therapy was not applied, the diagnostic value of EER was excellent, as well as for the detection of perirectal fat spread as for lymph node involvement. The diagnostic accuracy was respectively 87.2% (CI: 74-95) and 78.0% (CI: 62-90). After irradiation, the diagnostic value was much lower. The diagnostic accuracy was 60% (CI:33-84) and 40% (CI:18-68) for perirectal fat spread and nodal involvement, respectively. This loss of information was due to a decrease in specificity. Radiation treatment was responsible for the occurrence of hypoechoic nodal images and peritumoral hypoechoic areas resulting in an overestimation of the extent of involvement. After irradiation of a rectal malignant tumor, the classical EER signs are no longer adequate to predict locoregional involvement. Endosonographic semiology must be modified to describe the tumor response to non surgical treatment.

Adult↗
PubMed1992

Internal radiation therapy for hepatocellular carcinoma. Results of a French multicenter phase II trial of transarterial injection of iodine 131-labeled Lipiodol.

Preliminary Phase I trials have shown iodine 131 (131I)-Lipiodol (ethiodized oil; Laboratoires Guerbet, Aulnaysous-Bois, France) to be well tolerated and most likely effective in the treatment of hepatocellular carcinoma (HCC). In this multicenter Phase II trial, the authors tested the feasibility and reproducibility of this treatment in other medical institutions and evaluated its efficacy in 50 patients with unresectable Stage I or II HCC, by the classification of Okuda et al. The authors studied 47 men and 3 women (63.9 +/- 7.1 years old) with Stage I (n = 18) or II (n = 32) HCC, by the classification of Okuda et al., which was verified by histologic findings (n = 25), cytologic findings (n = 11), or association of a tumor with alpha-fetoprotein serum values greater than 500 micrograms/l (n = 14). This multicenter trial (1) confirmed that the 131I-Lipiodol treatment is well tolerated; (2) showed that there is a high reproducibility of results with respect to other institutions and an objective tumor response in 40% of the cases; and (3) indicated the necessity of performing a randomized controlled study.

Adult↗
PubMed1992

The sequence of a 9.3 kb segment located on the left arm of the yeast chromosome XI reveals five open reading frames including the CCE1 gene and putative products related to MYO2 and to the ribosomal protein L10.

We report here the sequence of a 9.3 kb DNA segment of chromosome XI of Saccharomyces cerevisiae, located between the MAK11 locus and the centromere. This sequence contains four long open reading frames (ORFs), YKL160, YKL162, YKL164, YKL165 and part of another ORF, YKL166, covering altogether 90% of the entire sequence. One of these ORFs, YKL164, corresponds to CCE1. Translation products of two other ORFs, YKL160 and YKL165, exhibit homology with previously known S. cerevisiae proteins: the ribosomal protein L10, and the MYO2 gene product, respectively.

Amino Acid Sequence↗
PubMed1992

Immunological characteristics of the putative CD4-binding site of the HIV-1 envelope protein.

As an extension of previous studies demonstrating the immunosuppressive properties of gp120, we have analyzed the immunological characteristics of gp120 peptides, derived principally from its putative CD4-binding site. Our studies indicate that peptides derived from this region do not stimulate proliferation of lymphocytes from HIV-seropositive donors with relatively normal numbers of CD4+ lymphocytes. No significant proliferation was observed in response to various concentrations of peptide, even in the presence of interleukin-2 (IL-2). Significant proliferation of these lymphocytes was observed in response to two recall antigens, cytomegalovirus (CMV) and tetanus toxoid (TT), and these responses were augmented by IL-2. Peripheral blood mononuclear cells from HIV-seronegative donors were cultured in the presence of TT and CMV and the peptides derived from gp120. Proliferation in the presence of these recall antigens was inhibited by these peptides in a dose-dependent manner. These studies demonstrate that at high concentrations, peptides from the putative CD4-binding site can inhibit proliferation of lymphocytes from normal donors in response to a recall antigen. The apparent immunosuppressive properties of this region highlight the pathogenic role played by HIV-1 envelope protein interactions with host cells.

Amino Acid Sequence↗
PubMed1992

Vertical transmission of human immunodeficiency virus (HIV) infection. Reactivity of maternal sera with glycoprotein 120 and 41 peptides from HIV type 1.

The observation that approximately 70% of HIV-infected pregnant women do not transmit infection vertically suggests that antibody therapy may be effective in the prevention of transmission of HIV infection from mother to child. Currently, there is an incomplete understanding of the processes involved in vertical transmission of HIV infection. The elucidation of the serological basis of maternal immunity as it relates to protection from vertical transmission is the goal of this study. We have screened 20 maternal sera from HIV+ individuals of known vertical transmission status for reactivity with 31 peptides spanning the entire envelope glycoprotein of HIV-1. Of interest was reactivity to regions outside of the V3 loop of gp120. The findings have been examined in relationship to transmission status, as well as to in vitro anti-HIV-1 biological activity. Our results indicate that lack of vertical transmission is correlated with high viral neutralization activity, but not with antisyncytial activity nor with binding to the V3 peptides examined in this study. Also, the transmission group bound to fewer gp41 peptides when compared with the nontransmission group, suggesting that immune responses to gp41 may be important in preventing transmission. These findings may provide insights into the design of passive immunotherapies.

Adult↗
PubMed1992

[Interstitial fibrosing pneumopathy and dermatomyositis. Pulmonary histology and prognosis].

The authors describe a case of interstitial lung disease associated with dermatomyositis. Alveolar-interstitial shadowing on the initial chest X-ray, lymphocytosis on the broncho-alveolar lavage fluid, absence of anti-JO1 antibodies and presence of intra-alveolar buds on the open lung biopsy were observed. Our patient died of acute respiratory failure, 34 months after symptoms onset. Intra-alveolar buds found at an early stage of dermatomyositis interstitial lung disease, were associated with minimal interstitial cellularity, markedly interstitial fibrosis, poor prognosis and poor response to steroid therapy. In contrary, bronchiolitis obliterans organizing pneumonia noted at an early stage of interstitial lung disease associated with both dermatomyositis and polymyositis, seems to have better prognosis and response to corticosteroid, especially if associated with polymyositis.

Bronchoalveolar Lavage Fluid↗
PubMed1992

[Predictive factors of response to chemotherapy in epidermoid cancer of the esophagus. Study apropos of 60 patients and evaluation of a response score].

The aim of this study was to select predictive factors for response to chemotherapy in esophageal squamous cell carcinoma. Sixty patients, aged between 39 and 77 years (mean 61.5) received two initial chemotherapy sessions of 5 FU (1 mg/m2/24 h) and cisplatinum (20 mg/m2/24 h) during four days. Sixteen clinical, endoscopic, biological, and histological factors were collected. The response to chemotherapy was evaluated one month after completion of the second session by means of endoscopic and computed tomographic data. Thirty-two percent (CI: 20-44 percent) of patients had an objective response to chemotherapy (according to WHO criteria). Univariate analysis showed two predictive factors: obstructing pattern of tumor (P less than 0.01) and albuminemia less than 35 g/l (P less than 0.01). A response score was calculated with a stepwise regression model. The score correctly predicted a satisfactory response to chemotherapy with a sensitivity and specificity of 84.2 and 73 percent, respectively. Overall survival of these patients was statistically higher (P less than 0.001) compared with patients without any response. A satisfactory response to chemotherapy in patients with esophageal squamous cell carcinoma can be expected according to certain pretreatment factors.

Aged↗
PubMed1992

[Analysis of cellular DNA content by flow cytometry in epidermoid carcinoma of the esophagus].

Flow cytometric DNA analysis was performed in 35 patients with squamous cell carcinoma of the esophagus. The aim of this study was a) to establish a tumoral DNA pattern, b) to determine an objective parameter correlating with tumoral response to chemotherapy (5 FU-cisplatin). DNA analysis was performed in perendoscopic ranged tumoral biopsy specimens to determine the DNA ploidy (DNA index) and S phase fraction. Tumor diameter and length were evaluated by computed tomography (CT) before and after chemotherapy in 24 patients. The relative variation of this product determined a CT index. Before chemotherapy, 82 percent (76/93) of the specimens were available for assessment; 72 percent (26/36) of the tumors were aneuploid. In these tumors, the DNA index ranged from 1.23 to 2.80. Five tumors had two distinct and simultaneous aneuploid populations. CT index values were not significantly different according to the ploidy (diploid, aneuploid), the S phase fraction (low, high), the DNA content modification after chemotherapy (absent, present). In this study, DNA analysis did not allow to select patients with higher response to chemotherapy. The inter- and intratumoral phenotypic heterogeneity may be one of the responsible factors.

Adult↗
PubMed1991

Effect of ethanol intake on lipoprotein lipase activity in rat heart.

We examined the effects of the in vivo administration of ethanol on lipolytic activities assayed in rat post-heparin heart effluents, that hydrolyse tri-, di- and monoacylglycerol. Properties of triacylglycerol lipase (TAGL) are typical of lipoprotein lipase (LPL) whereas diacylglycerol (DAGL) and monoacylglycerol (MAGL) lipase activities hydrolyse sequentially the products of LPL action. After 15 days of ethanol intake, TAGL, DAGL and MAGL activities in post-heparin heart effluents were decreased respectively by 25, 38 and 22%; after 30 days, the decreases amounted to 81, 79 and 71%. After 30 days, but not after 15 days, ethanol increased the levels of triacylglycerol in plasma. Ethanol intake concomitantly decreased TAGL and DAGL activities in post-heparin effluents and in heart tissue extracts, whereas MAGL activity was decreased only in the latter extracts. We conclude that ethanol intake causes a marked impairment in heart LPL and in two closely-related heparin-releasable activities, seemingly by altering the production of a catalytically active enzyme. A distinct heparin-unreleasable MAGL appears to exist in heart, that could be ethanol-insensitive. Overall, the results suggest that a LPL-related alteration in fatty acid supply could contribute to the toxicity of ethanol in heart.

Alcohol Drinking↗