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Biomedical subjects

G Rossignol

Publications and source records attributed to G Rossignol.

At least 37 records · Page 2Linked to original sources
PubMed1989

Metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone by hamster respiratory tissues cultured with ellagic acid.

Previous studies have shown that the nicotine-derived N-nitrosamine-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) induces tracheal papillomas and lung carcinomas in Syrian golden hamsters. In this study, we showed that hamster tracheal and lung explants metabolize NNK by alpha-carbon hydroxylation, pyridine N-oxidation and carbonyl reduction. alpha-Methylene hydroxylation and methyl hydroxylation yield methylating and pyridyloxobutylating intermediates, respectively. Levels of binding of the pyridyloxobutyl moiety to explant proteins was 200 times lower than the total amount of metabolites formed by alpha-carbon hydroxylation and released in the culture medium. Viable and heat-treated lung explants were cultured with [CH3-3H]NNK or [5-3H]NNK. In viable explants, the rate of binding of the methyl group was 2-fold higher than the rate of binding of the pyridyloxobutyl moiety of NNK. Heat treatment reduced 54-fold the binding of [CH3-3H] NNK but only 5-fold the binding [5-3H]NNK. Tracheal explants were cultured with [5-3H]NNK (5.6 microM) and ellagic acid (EA, 10 microM), a naturally-occurring plant phenol. EA did not inhibit any of the three metabolic pathways nor the binding of the pyridyloxobutyl moiety to explant proteins. Lung explants were cultured with NNK (3.7 microM) and with or without EA (100 microM). EA inhibits alpha-carbon hydroxylation by 19% and the overall metabolism of NNK by 6%. Formation of 7-methylguanine and O6-methylguanine was observed in lung explants and the levels of both adducts were reduced by EA (100 microM). These results suggest that high concentrations of EA modulate the metabolism of NNK and that NNK does not necessarily require enzymatic activation to bind to protein.

Alkylation↗
PubMed1989

In vitro and in vivo modulation of the bioactivation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone in hamster lung tissues.

The metabolism of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) by hamster lung explants was studied. The three major metabolic pathways were alpha-C-hydroxylation (activation), pyridine N-oxidation (deactivation) and carbonyl reduction. alpha-C-Hydroxylation and pyridine N-oxidation were linear with time (0.5-5 h) and number of explants per dish (3-10). Addition of [2-(diethylamino)ethyl 2,2-diphenylpentenoate] hydrochloride (SKF-525A) to the culture medium reduced alpha-C-hydroxylation and pyridine N-oxidation. alpha-C-Hydroxylation was enhanced by treatment of the hamsters with the two cytochrome P-450 inducers, phenobarbital and 3-methylcholanthrene. These results suggest that cytochrome P-450 monooxygenases are involved in the activation of NNK by alpha-C-hydroxylation. Three groups of hamsters were fed a control diet or diet supplemented with 2% 2(3)-tert-butyl 4-hydroxyanisole (2(3)-BHA) or given a 0.002% solution of (S)-nicotine to drink for two weeks. Lung explants were then cultured with NNK in vitro. Treatment with 2(3)-BHA and (S)-nicotine induced the alpha-C-hydroxylation pathways. Pyridine N-oxidation was increased by (S)-nicotine treatment. These results indicate that dietary factors and tobacco smoke components can modulate the metabolism of NNK.

Animals↗
PubMed1989

Transplacental genotoxicity of a tobacco-specific N-nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, in Syrian golden hamster.

NNK is abundant in cigarette smoke and is a potent respiratory carcinogen in adult Syrian golden hamsters. Micronucleus (MN) induction in fetal liver and maternal bone marrow polychromatic erythrocytes (PCEs) were assayed after i.p. injection of NNK to 14-day pregnant hamsters. The frequency of MN induction observed in fetal PCEs reached a maximum 18 h after treatment. The relationship dose NNK (0-200 mg/kg) to MN frequency was significant (P less than 0.005). In contrast no significant MN induction was observed in adult bone-marrow PCEs (P greater than 0.1). Extraction of fetal liver and amniotic fluid and HPLC separation of NNK metabolites revealed that NNK and its metabolite NNA1 could cross the placental barrier and be activated to protein-binding intermediates. These results suggest that NNK could be a transplancental carcinogen in Syrian golden hamsters.

Animals↗
PubMed1989

In vitro morphological changes induced by 4-(methylnitrosamino)-1-(3-pyridyl)-1-(butanone) in fetal hamster respiratory tract tissue.

Previous studies conducted in our laboratories have shown that the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is metabolized by fetal hamster respiratory tissues to form DNA-alkylating and clastogenic intermediates. This study was conducted to explore if morphological changes compatible with such events could be detected. Explants of fetal hamster tracheas and lungs were exposed in vitro to various concentrations of NNK and investigated by light and electron microscopy. The explants demonstrated dose dependent preneoplastic lesions in the trachea, while the lung explants exhibited morphological changes compatible with disturbed production and/or release of surfactant.

Animals↗
PubMed1989

[External radiotherapy after radical prostatectomy for cancer of the prostate, stage C or DI. Preliminary study].

Between february 1985 and february 1988, 45 patients upstaged to stages C or D 1 cancer after radical prostatectomy, were treated by adjuvant radiotherapy with a view to control the risk of local recurrence and distant metastases. Radical prostatectomy has a low morbidity (less than 10%) whereas the radiotherapy morbidity rate is important (40% with 10% severe complications). With an average 33.4 months follow-up, we observe cancer dissemination in 37.7% of the cases and local recurrence in 13.3% of the cases. The prognosis seems to be worse, on one hand when the urethral margins are invaded and/or when the seminal vesicles are macroscopically invaded (C3) and on the other hand when the pelvic nodes are macroscopically invaded. Radiotherapy avoids locals recurrence in some cases but does not permit a general control of the disease. This observation leads us to recommend an early postoperative hormonotherapy in patients upstaged to stage C3 or with positive nodes.

Aged↗
PubMed1987

[Pharmacologic study of nicergoline in the pathology of the cervico-prostatic sphincter].

An urodynamic survey and an E.M.G. of the striated sphincters were performed in 20 patients presenting with prostatism, before and after infusion of either nicergoline or placebo, under double-blind conditions. Statistical analysis was performed and demonstrated a significant decrease in the tone of the bladder neck, the prostate, the striated sphincter and the bladder; impoverished electromyographic activity of the striated sphincters; increased maximal and mean urine flow and decreased post-voiding residue. The authors stress the efficacy of nicergoline in cervico-prostato-sphincteric syndromes.

Clinical Trials as Topic↗
PubMed1987

[Uretero-ileal anastomosis using the modified Leduc-Camey technic. Surgical technic].

A modified Leduc-Camey technic for uretero-ileal anastomosis was used in 96 patients over a period of one year, complications related to this type of anastomosis, and requiring recovery surgery, being noted in 2 cases. When compared with more than 300 anastomoses performed using the original Leduc-Camey technic, this modified procedure using absorbable sutures appeared to be simple, effective and very rapid. It is a valid method for Camey type reconstruction bladders and also for Bricker type or Kock's pouch type continent diversion operations.

Adult↗
PubMed1986

[Pheochromocytoma with multiple localizations manifested by a hemorrhagic bladder tumor].

Pheochromocytoma is an endocrine tumor derived from neuroectodermal tissue. Pheochromocytomas usually arises in the adrenal glands but may develop in other organs. We report a case of pheochromocytoma of the bladder with hematuria as the presenting symptom. This tumor was removed by partial cystectomy. Following this procedure, biologic disorders persisted (catecholamines, vandylmandelic acid and metanephrines) leading to the diagnosis of an adrenal pheochromocytoma. The patient recovered after removal of the adrenal tumor. Discussion, review of the literature and bibliography.

Adrenal Gland Neoplasms↗
PubMed1986

[Total prostatectomy with preservation of erection. Surgical technic].

The authors describe their technique to preserve the erector nerves during a radical retropubic prostatectomy. In the first part, the different phases of the operation are described. The 2nd part consists of discussion based on the author's experiences (20 cases of nerve preservation in a series of 115 radical prostatectomies). The authors stress the insufficient oncological follow-up and the risk of an incorrect indication due to understaging of the cancer in pre-operative period.

Humans↗
PubMed1986

[Radical prostatectomy in cancer of the prostate. Our experience apropos of 55 cases with 3-year follow-up].

The authors report their experience of retropubic radical prostatectomy for prostatic cancer. They have performed 55 prostatectomies over a period of 3 years. Their indications are essentially stage B (35 cases) and stage C1 (20 cases). The post-operative morbidity was low and no cases of incontinence were observed. Post-operative impotence generally occurs when the cavernous nerves are interrupted. However, erection was preserved in two cases when Walsh's technique was used.

Adenocarcinoma↗
PubMed1985

[Evaluation of erection disorder].

A multidisciplinary approach to screening for a disorder of erection has been applied over the last 7 years and involves dynamic and particularly physiologic explorations. When an organic etiology cannot be excluded during the first consultation and after a clinical examination, the basic paraclinical investigation used is the measurement of nocturnal erections (NPT). Although NPT remains the key-examination, it may be necessary to request vascular exploration, mainly study of the Döppler effect, a neurologic examination to include peripheral and autonomic nervous systems and endocrine tests.

Body Temperature↗
PubMed1985

[Hydraulic penile prostheses in the surgery of impotence. Our experience in 20 cases with a 2-year follow-up].

The authors report their experience of the implantation of inflatable penile prostheses in the surgical management of impotence. They have implanted twenty prostheses with a followup of two years to three months. The overall results are very satisfactory in terms of the quality of the sexual life of the couple (85%). On the other hand, the postoperative morbidity rate is high, with 40% of complications including 20% requiring reoperation.

Adult↗
PubMed1981

Successful autotransplantation of an intra-abdominal testis by microsurgery.

An intra-abdominal testis in a 12-year-old child was successfully transplanted to the scrotum by a microvascular technique. The result after 12 months is promising. Problems of ischaemia in testicular autotransplantation and technical problems in testes with a short spermatic pedicle are emphasized.

Abdomen↗
PubMed1981

[Personal experience of sleep plethysmography in the differential diagnosis of erection disturbances (author's transl)].

The authors feel that penile erection during sleep represents the first stage in the investigation of erection problems. The aim is to distinguish between psychogenic impotence the organic impotence. The authors simultaneously perform plethysmography and an electroencephalogram during sleep. Sixty five patients have been investigated in this way. In 44 cases the occurrence of nocturnal penile erection led to the conclusion of a psychogenic origin whilst in 21 cases the results of plethysmography were pathological. Amongst these 21 patients, undergoing vascular investigations, 12 underwent revascularisation of the corpora cavernosa and 12 the insertion of an erection prosthesis. It may be noted that revascularization using the epigastric artery gave widely disparate results: 2 good results amongst 9 patients, with one failure and six inadequate erections. The authors emphasise the fact that there is little alteration in sleep in cases of organic impotence and that phases of paradoxal sleep recur periodically without any great variation in the plethysmographic curve. By contrast, in functional impotence, sleep is invariably disturbed. A whole series of factors are involved in the assessment of the results: total duration of sleep, duration of paradoxal sleep, ratio of paradoxal sleep to total sleep, total erection time, total time in maximum erection and the ratio of erection time to paradoxal sleep. Analysis of sleep is thus a fundamental factor in the proper interpretation of the results of plethysmography in an importance sufferer.

Diagnosis, Differential↗
PubMed1980

Vascular microsurgery in the ex situ kidney. An experimental study.

Work in vascular microsurgery is presented. We previously studied the vascular network and the pyelocaliceal system in the dog by means of moulding. Vascular microsurgery was practised on small animals. Operative protocol on the kidney was performed ex situ in 15 dogs. Our results with arteriographic and pathological control are presented.

Animals↗