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Biomedical subjects

B Bonnotte

Publications and source records attributed to B Bonnotte.

At least 19 recordsLinked to original sources
PubMed2005

[Acute nonalcoholic nonbiliary pancreatitis. Difficulties in diagnosis and possibility of nicotine toxicity].

INTRODUCTION: The possibility of nicotine toxicity, although rare, should be considered in cases of acute edematous pancreatitis. CASE: A 30-year-old woman was hospitalized to identify the cause of an initial episode of acute edematous pancreatitis. The observation of native anti-DNA and antiphospholipid antibodies suggested lupus pancreatitis and/or an antiphospholipid syndrome, both subsequently ruled out. The final diagnosis was nicotine poisoning induced by the combination of a nicotine patch and tobacco smoking. CONCLUSION: Although a nicotine patch has never been reported in connection with an episode of acute pancreatitis before, this case suggests that such an event might be a rare complication of an overdose of nicotine.

Acute Disease↗
PubMed2004

[Pathogenic mechanisms of autoimmune diseases].

BACKGROUND: Auto-immune diseases are a fascinating but poorly understood group of diseases. MAJOR POINTS: In this review, we will consider genetic susceptibility to auto-immune diseases, initiation of autoreactivity and changes in pathologic processes. Recent physiopathological hypotheses are detailed with clinical examples. PERSPECTIVES: A better knowledge of the physiopathological mechanisms would allow the development of more efficacious treatments.

Animals↗
PubMed2002

[Elevation of serum lactate dehydrogenase. Diagnostic, prognostic and evolutive values].

OBJECTIVE: Determination of serum lactate dehydrogenase (LDH) levels is an usual practice. However, its place in the diagnosis process is not clear. We have collected serum LDH levels superior to 2-fold the normal rate and we tried to determine their diagnostics interest and, predictive and progressive values. METHODS: Retrospective study during 3 months in hospitalized adults. LDH levels were measured by spectrophotometry (Normal rate: 313-618 UI/L). RESULTS: 196 cases with LDH level elevations higher than 1236 UI/L were analyzed. The etiology of LDH level elevations were was benign in 60% of cases, malignant in 36% and, undetermined in 5%. There was no difference in between average values of LDH level average values of benign and malignant etiology (2708 vs 2842 UI/l). LDH rates and high LDH level elevations were not helpful for in the diagnosis process (a variety of 43 etiology was able to elevate increased LDH rates). In 45% cases, LDH level was 2 to 3-fold the normal rate; in 47.5% cases, 3 to 10-fold normal rate, and in 7.5% cases, superior to 10-fold normal rate. LDH elevations superior to 10-fold the normal rate were caused by benign etiology in 11 cases and malignant disease in 4 cases. A level superior to 10-fold the normal rate was not helpful in determining to determine the benign or malignant characteristics of the initial disease. However, LDH rate superior to 10 normal rate was a pejorative predictive criteria (hospitalization in intensive careunity in 73% of cases and mortality rate of 53%). During follow up of a neoplasia or malignant hemopathy follow up, several LDH measurements LDH level determinations were determined in for a small number of patients. LDH level normalizations is are attributable to efficientan effective treatment; LDH level elevations are associated with a therapeutic failure echappment. Evolution in LDH levels evolution was influenced by progression in neoplasia and malignant hemopathy evolution and also by various several treatments such as like blood transfusions, growth factors, radiotherapy and chemotherapy. CONCLUSION: LDH level elevation, however whatever its rate, don't seem to do not help in differentiating have interest to differentiate benign from malignant diseases. However, an elevation LDH elevation higher than 10-fold the normal rate is a pejorative predictive criteria, since because the mortality rate is superior toupper than 50%. During follow-up of in the neoplasia and malignant hemopathy follow up, so long as they are measured at distance from treatment, variations in LDH levels are a good marker of evolution, rate variations represent an evolutive marker conditionally the level determination would be realize remote several treatment.

Adolescent↗
PubMed2001

Identification of tumor-infiltrating macrophages as the killers of tumor cells after immunization in a rat model system.

Immunization can prevent tumor growth, but the effector cells directly responsible for tumor cell killing in immunized hosts remain undetermined. The present study compares tumor grafts that progress in naive syngeneic rats with the same grafts that completely regress in hosts preimmunized with an immunogenic cell variant. The progressive tumors contain only a few macrophages that remain at the periphery of the tumor without direct contact with the cancer cells. These macrophages do not kill tumor cells in vitro. In contrast, tumors grafted in immunized hosts and examined at the beginning of tumor regression show a dramatic infiltration with mature macrophages, many of them in direct contact with the cancer cells. These macrophages are strongly cytotoxic for the tumor cells in vitro. In contrast to macrophages, tumor-associated lymphocytes are not directly cytotoxic to the tumor cells, even when obtained from tumor-immune rats. However, CD4(+) and CD8(+) T cells prepared from the regressing tumors induce tumoricidal activity in splenic macrophages from normal or tumor-bearing rats and in macrophages that infiltrate progressive tumors. These results strongly suggest that the main tumoricidal effector cells in preimmunized rats are macrophages that have been activated by adjacent tumor-immune lymphocytes.

Animals↗
PubMed2001

Central nervous system disease in patients with macrophagic myofasciitis.

Macrophagic myofasciitis (MMF), a condition newly recognized in France, is manifested by diffuse myalgias and characterized by highly specific myopathological alterations which have recently been shown to represent an unusually persistent local reaction to intramuscular injections of aluminium-containing vaccines. Among 92 MMF patients recognized so far, eight of them, which included the seven patients reported here, had a symptomatic demyelinating CNS disorder. CNS manifestations included hemisensory or sensorimotor symptoms (four out of seven), bilateral pyramidal signs (six out of seven), cerebellar signs (four out of seven), visual loss (two out of seven), cognitive and behavioural disorders (one out of seven) and bladder dysfunction (one out of seven). Brain T(2)-weighted MRI showed single (two out of seven) or multiple (four out of seven) supratentorial white matter hyperintense signals and corpus callosum atrophy (one out of seven). Evoked potentials were abnormal in four out of six patients and CSF in four out of seven. According to Poser's criteria for multiple sclerosis, the diagnosis was clinically definite (five out of seven) or clinically probable multiple sclerosis (two out of seven). Six out of seven patients had diffuse myalgias. Deltoid muscle biopsy showed stereotypical accumulations of PAS (periodic acid-Schiff)-positive macrophages, sparse CD8+ T cells and minimal myofibre damage. Aluminium-containing vaccines had been administered 3-78 months (median = 33 months) before muscle biopsy (hepatitis B virus: four out of seven, tetanus toxoid: one out of seven, both hepatitis B virus and tetanus toxoid: two out of seven). The association between MMF and multiple sclerosis-like disorders may give new insights into the controversial issues surrounding vaccinations and demyelinating CNS disorders. Deltoid muscle biopsy searching for myopathological alterations of MMF should be performed in multiple sclerosis patients with diffuse myalgias.

Adult↗
PubMed2000

Flt3 ligand lessens the growth of tumors obtained after colon cancer cell injection in rats but does not restore tumor-suppressed dendritic cell function.

A defective function of the antigen-presenting cells may represent one of the ways used by cancer cells to escape the immune response. We have previously shown that human and rat colon carcinomas were infiltrated by dendritic cells that did not express the B7 co-stimulatory molecules required for inducing an efficient T-cell response. Flt3 ligand is a cloned hematopoietic growth factor that markedly augments the number of functional dendritic and NK cells in lymphoid and non-lymphoid tissues and exerts anti-tumor activity in various experimental models. We show here that repeated Flt3 ligand administration delays the s.c. growth of rat colon cancer cells in syngeneic animals without inducing tumor regression. In tumor-bearing animals, Flt3 ligand has a limited stimulatory effect on the antigen-presenting capacity of intra-tumoral and splenic dendritic cells, without restoring the high functional level of dendritic cells from tumor-free animals. Moreover, Flt3 ligand-mediated activation of NK cell cytotoxicity decreases when the tumor mass increases. Our results indicate that Flt3 ligand treatment of tumor-bearing animals does not sufficiently overcome tumor-induced immunosuppression to restore the inhibited functions of dendritic and NK cells and allow complete tumor regression.

Animals↗
PubMed2000

Cutting edge: the tumor counterattack hypothesis revisited: colon cancer cells do not induce T cell apoptosis via the Fas (CD95, APO-1) pathway.

The counterattack hypothesis, suggesting that cancer cells express Fas ligand (FasL) and are able to kill Fas-expressing tumor-infiltrating activated T cells, was supported by reports of the killing of Jurkat cells by FasL-expressing human colon cancer cell lines. Through the use of an improved cytotoxic assay in which soluble FasL and FasL-transfected KFL9 cells were used as positive controls, we show that none of seven human colon cancer cell lines induce apoptosis of two Fas-expressing target cell lines, Jurkat and L1210-Fas cells. Moreover, in coculture experiments, cancer cell monolayers do not inhibit the growth of Fas-expressing lymphoid cells. Although FasL mRNA and protein were detected in the extracts of the colon cancer cell lines, flow cytometry and confocal microscopy failed to detect the protein on the surface of tumor cells. These results suggest that the counterattack of tumor-infiltrating T lymphocytes by cancer cells may not account for immune tolerance toward tumor cells.

Animals↗
PubMed2000

Role of tumor cell apoptosis in tumor antigen migration to the draining lymph nodes.

Establishment of an immune response against cancer may depend on the capacity of dendritic cells to transfer tumor Ags into T cell-rich areas. To check this possibility, we used a colon cancer cell variant that yields tumors undergoing complete T cell-dependent rejection when injected into syngeneic rats. We previously demonstrated that immunogenicity of these tumors depended on the early apoptosis of a part of these tumor cells. In this paper we show that fluorescent tumor cell proteins are released from FITC-labeled tumor cells and undergo engulfment by tumor-infiltrating monocytes without a phenotype of mature dendritic cells or macrophages. Fluorescence-labeled mononuclear cells with a phenotype of MHC class II+ dendritic cells are also found in the T cell areas of the draining lymph nodes. Interestingly, no fluorescent cell can be found in lymph nodes after a s.c. injection of Bcl2-transfected apoptosis-resistant tumor cells that yielded progressive tumors. Proliferation of tumor-immune T lymphocytes was induced by dendritic cells isolated from the draining lymph nodes recovered after a s.c. injection of apoptosis-sensitive, but not apoptosis-resistant, tumor cells. These results show that tumor cell apoptosis releases proteins that are engulfed by inflammatory cells in the tumor, then transported to lymph node T cell areas where they can induce a specific immune response leading to tumor rejection.

Adenocarcinoma↗
PubMed1999

FAS(CD95) ligand expression by tumor cell variants can be unrelated to their capacity to induce tolerance or immune rejection.

According to the results of in vitro experiments, Fas(CD95) ligand expression by cancer cells might induce apoptosis of activated T cells and contribute to immune tolerance. However, Fas ligand expression had never been explored in vivo in tumor cell models yielding either immune response or tolerance. In the present study, we analyzed the expression and function of Fas ligand in 2 clones of tumor cells originating from the same rat colon carcinoma. REGb cells were immunogenic and yielded tumors that regressed in immunecompetent syngeneic hosts, whereas PROb cells induced active tolerance and yielded progressive tumors. Fas ligand was expressed on the plasma membrane of both REGb and PROb cells, and its cDNA sequencing showed no mutation. However, neither REGb nor PROb cells induced apoptosis of co-cultured Fas-sensitive target cells. Our results show that surface expression of Fas ligand by tumor cells does not always induce killing of adjoining Fas-sensitive cells and that tumor cells may induce a protective immune response or an active tolerance independently of Fas ligand expression.

Animals↗
PubMed1999

[Early signs of systemic disease in patients taking minocycline chlorhydrate].

BACKGROUND: Search for etiology in young subjects with joint disease must take into consideration causes other than reactional arthropathy or systemic disease. CASE REPORTS: Two young subjects consulted for joint pain involving various joints. Physical examination did not reveal any other abnormality. Serum tests were positive for antinuclear antibodies and/or showed moderately and persistently elevated transaminases. History taking revealed that these subjects had been taking minocyclin chlorhydrate for several months, or even years, for acne. Joint pain subsided with drug withdrawal and serum tests returned to normal. DISCUSSION: Long-term treatment with minocylin chlorhydrate should always be included in the search for an etiology in patients presenting joint pain.

Adolescent↗
PubMed1998

[Anticancer chemotherapy. Prevention of toxicity].

A MAJOR CHALLENGE: Prevention of short and long term toxicity of chemotherapy is an important challenge in oncology in order to maintain the dose/intensity of protocols and to increase patient comfort. AVAILABLE CHEMOPROTECTORS: Amifostine protects against the blood, kidney and nerve toxicity of cisplatin. Protection is less evident for carboplatin and should be further evaluated for alkylating agents, anthracyclines and taxans. Dexrazoxane protects against the cumulative cardiotoxicity of anthracyclines without reduction of antitumor efficacy. It must be used beyond a cumulative dose of 300 mg/m2 doxorubicin (or equivalent) in responsive patients. Its use in the curative treatment of lymphoma should be assessed by further clinical trials. Mesna must be widely used to prevent the urotoxicity of cyclophosphamide and ifosfamide. An oral preparation is now available for outpatients. Protection of the gonadic function could be achieved by LH-FH analogs in young women. PERSPECTIVES: Due to their high cost and the risk of diminishing the antitumor efficacy in curable diseases, a precise evaluation of present and future chemoprotectors is necessary before wider use.

Amifostine↗
PubMed1998

Heat shock protein 27 enhances the tumorigenicity of immunogenic rat colon carcinoma cell clones.

The REG and PRO cell clones were obtained from a colon adenocarcinoma induced in a BDIX rat by 1,2-dimethylhydrazine. When injected s.c. into syngeneic hosts, REG cells induce tumors that regress in less than 3 weeks, whereas PRO cells, like parental cells, induce progressive tumors. Here, we show that compared to PRO cells, REG cells are more sensitive to cell death induced by anticancer drugs. The small heat shock protein (HSP) 27 is not expressed or inducible in REG clones, whereas it is abundantly expressed and inducible by heat shock in PRO clones. The expression of HSP27 in REG cells increases their resistance to apoptosis in vitro and dramatically enhances their tumorigenicity when injected s.c. into syngeneic rats. HSP27 expression in REG cells both increases tumor size and delays tumor regression. This increased tumorigenicity is associated with a substantial decrease of in vivo tumor cell apoptosis. We conclude that HSP27 expression in malignant cells increases their tumorigenicity in syngeneic animals. In combination with the role of HSP27 in tumor cell resistance to cytotoxic agents, its contribution to tumorigenicity makes this protein a potential target for antitumoral therapy.

Adenocarcinoma↗